1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
54 #include <linux/highmem.h>
55 #include <linux/pgtable.h>
56 #include <linux/buildid.h>
57 #include <linux/task_work.h>
61 #include <asm/irq_regs.h>
63 typedef int (*remote_function_f)(void *);
65 struct remote_function_call {
66 struct task_struct *p;
67 remote_function_f func;
72 static void remote_function(void *data)
74 struct remote_function_call *tfc = data;
75 struct task_struct *p = tfc->p;
79 if (task_cpu(p) != smp_processor_id())
83 * Now that we're on right CPU with IRQs disabled, we can test
84 * if we hit the right task without races.
87 tfc->ret = -ESRCH; /* No such (running) process */
92 tfc->ret = tfc->func(tfc->info);
96 * task_function_call - call a function on the cpu on which a task runs
97 * @p: the task to evaluate
98 * @func: the function to be called
99 * @info: the function call argument
101 * Calls the function @func when the task is currently running. This might
102 * be on the current CPU, which just calls the function directly. This will
103 * retry due to any failures in smp_call_function_single(), such as if the
104 * task_cpu() goes offline concurrently.
106 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
109 task_function_call(struct task_struct *p, remote_function_f func, void *info)
111 struct remote_function_call data = {
120 ret = smp_call_function_single(task_cpu(p), remote_function,
135 * cpu_function_call - call a function on the cpu
136 * @cpu: target cpu to queue this function
137 * @func: the function to be called
138 * @info: the function call argument
140 * Calls the function @func on the remote cpu.
142 * returns: @func return value or -ENXIO when the cpu is offline
144 static int cpu_function_call(int cpu, remote_function_f func, void *info)
146 struct remote_function_call data = {
150 .ret = -ENXIO, /* No such CPU */
153 smp_call_function_single(cpu, remote_function, &data, 1);
158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
159 struct perf_event_context *ctx)
161 raw_spin_lock(&cpuctx->ctx.lock);
163 raw_spin_lock(&ctx->lock);
166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
167 struct perf_event_context *ctx)
170 raw_spin_unlock(&ctx->lock);
171 raw_spin_unlock(&cpuctx->ctx.lock);
174 #define TASK_TOMBSTONE ((void *)-1L)
176 static bool is_kernel_event(struct perf_event *event)
178 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
181 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context);
183 struct perf_event_context *perf_cpu_task_ctx(void)
185 lockdep_assert_irqs_disabled();
186 return this_cpu_ptr(&perf_cpu_context)->task_ctx;
190 * On task ctx scheduling...
192 * When !ctx->nr_events a task context will not be scheduled. This means
193 * we can disable the scheduler hooks (for performance) without leaving
194 * pending task ctx state.
196 * This however results in two special cases:
198 * - removing the last event from a task ctx; this is relatively straight
199 * forward and is done in __perf_remove_from_context.
201 * - adding the first event to a task ctx; this is tricky because we cannot
202 * rely on ctx->is_active and therefore cannot use event_function_call().
203 * See perf_install_in_context().
205 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
208 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
209 struct perf_event_context *, void *);
211 struct event_function_struct {
212 struct perf_event *event;
217 static int event_function(void *info)
219 struct event_function_struct *efs = info;
220 struct perf_event *event = efs->event;
221 struct perf_event_context *ctx = event->ctx;
222 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
223 struct perf_event_context *task_ctx = cpuctx->task_ctx;
226 lockdep_assert_irqs_disabled();
228 perf_ctx_lock(cpuctx, task_ctx);
230 * Since we do the IPI call without holding ctx->lock things can have
231 * changed, double check we hit the task we set out to hit.
234 if (ctx->task != current) {
240 * We only use event_function_call() on established contexts,
241 * and event_function() is only ever called when active (or
242 * rather, we'll have bailed in task_function_call() or the
243 * above ctx->task != current test), therefore we must have
244 * ctx->is_active here.
246 WARN_ON_ONCE(!ctx->is_active);
248 * And since we have ctx->is_active, cpuctx->task_ctx must
251 WARN_ON_ONCE(task_ctx != ctx);
253 WARN_ON_ONCE(&cpuctx->ctx != ctx);
256 efs->func(event, cpuctx, ctx, efs->data);
258 perf_ctx_unlock(cpuctx, task_ctx);
263 static void event_function_call(struct perf_event *event, event_f func, void *data)
265 struct perf_event_context *ctx = event->ctx;
266 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
267 struct event_function_struct efs = {
273 if (!event->parent) {
275 * If this is a !child event, we must hold ctx::mutex to
276 * stabilize the event->ctx relation. See
277 * perf_event_ctx_lock().
279 lockdep_assert_held(&ctx->mutex);
283 cpu_function_call(event->cpu, event_function, &efs);
287 if (task == TASK_TOMBSTONE)
291 if (!task_function_call(task, event_function, &efs))
294 raw_spin_lock_irq(&ctx->lock);
296 * Reload the task pointer, it might have been changed by
297 * a concurrent perf_event_context_sched_out().
300 if (task == TASK_TOMBSTONE) {
301 raw_spin_unlock_irq(&ctx->lock);
304 if (ctx->is_active) {
305 raw_spin_unlock_irq(&ctx->lock);
308 func(event, NULL, ctx, data);
309 raw_spin_unlock_irq(&ctx->lock);
313 * Similar to event_function_call() + event_function(), but hard assumes IRQs
314 * are already disabled and we're on the right CPU.
316 static void event_function_local(struct perf_event *event, event_f func, void *data)
318 struct perf_event_context *ctx = event->ctx;
319 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
320 struct task_struct *task = READ_ONCE(ctx->task);
321 struct perf_event_context *task_ctx = NULL;
323 lockdep_assert_irqs_disabled();
326 if (task == TASK_TOMBSTONE)
332 perf_ctx_lock(cpuctx, task_ctx);
335 if (task == TASK_TOMBSTONE)
340 * We must be either inactive or active and the right task,
341 * otherwise we're screwed, since we cannot IPI to somewhere
344 if (ctx->is_active) {
345 if (WARN_ON_ONCE(task != current))
348 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
352 WARN_ON_ONCE(&cpuctx->ctx != ctx);
355 func(event, cpuctx, ctx, data);
357 perf_ctx_unlock(cpuctx, task_ctx);
360 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
361 PERF_FLAG_FD_OUTPUT |\
362 PERF_FLAG_PID_CGROUP |\
363 PERF_FLAG_FD_CLOEXEC)
366 * branch priv levels that need permission checks
368 #define PERF_SAMPLE_BRANCH_PERM_PLM \
369 (PERF_SAMPLE_BRANCH_KERNEL |\
370 PERF_SAMPLE_BRANCH_HV)
373 EVENT_FLEXIBLE = 0x1,
376 /* see ctx_resched() for details */
379 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
383 * perf_sched_events : >0 events exist
386 static void perf_sched_delayed(struct work_struct *work);
387 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
388 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
389 static DEFINE_MUTEX(perf_sched_mutex);
390 static atomic_t perf_sched_count;
392 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
394 static atomic_t nr_mmap_events __read_mostly;
395 static atomic_t nr_comm_events __read_mostly;
396 static atomic_t nr_namespaces_events __read_mostly;
397 static atomic_t nr_task_events __read_mostly;
398 static atomic_t nr_freq_events __read_mostly;
399 static atomic_t nr_switch_events __read_mostly;
400 static atomic_t nr_ksymbol_events __read_mostly;
401 static atomic_t nr_bpf_events __read_mostly;
402 static atomic_t nr_cgroup_events __read_mostly;
403 static atomic_t nr_text_poke_events __read_mostly;
404 static atomic_t nr_build_id_events __read_mostly;
406 static LIST_HEAD(pmus);
407 static DEFINE_MUTEX(pmus_lock);
408 static struct srcu_struct pmus_srcu;
409 static cpumask_var_t perf_online_mask;
410 static struct kmem_cache *perf_event_cache;
413 * perf event paranoia level:
414 * -1 - not paranoid at all
415 * 0 - disallow raw tracepoint access for unpriv
416 * 1 - disallow cpu events for unpriv
417 * 2 - disallow kernel profiling for unpriv
419 int sysctl_perf_event_paranoid __read_mostly = 2;
421 /* Minimum for 512 kiB + 1 user control page */
422 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
425 * max perf event sample rate
427 #define DEFAULT_MAX_SAMPLE_RATE 100000
428 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
429 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
431 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
433 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
434 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
436 static int perf_sample_allowed_ns __read_mostly =
437 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
439 static void update_perf_cpu_limits(void)
441 u64 tmp = perf_sample_period_ns;
443 tmp *= sysctl_perf_cpu_time_max_percent;
444 tmp = div_u64(tmp, 100);
448 WRITE_ONCE(perf_sample_allowed_ns, tmp);
451 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc);
453 int perf_event_max_sample_rate_handler(struct ctl_table *table, int write,
454 void *buffer, size_t *lenp, loff_t *ppos)
457 int perf_cpu = sysctl_perf_cpu_time_max_percent;
459 * If throttling is disabled don't allow the write:
461 if (write && (perf_cpu == 100 || perf_cpu == 0))
464 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
468 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
469 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
470 update_perf_cpu_limits();
475 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
477 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
478 void *buffer, size_t *lenp, loff_t *ppos)
480 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
485 if (sysctl_perf_cpu_time_max_percent == 100 ||
486 sysctl_perf_cpu_time_max_percent == 0) {
488 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
489 WRITE_ONCE(perf_sample_allowed_ns, 0);
491 update_perf_cpu_limits();
498 * perf samples are done in some very critical code paths (NMIs).
499 * If they take too much CPU time, the system can lock up and not
500 * get any real work done. This will drop the sample rate when
501 * we detect that events are taking too long.
503 #define NR_ACCUMULATED_SAMPLES 128
504 static DEFINE_PER_CPU(u64, running_sample_length);
506 static u64 __report_avg;
507 static u64 __report_allowed;
509 static void perf_duration_warn(struct irq_work *w)
511 printk_ratelimited(KERN_INFO
512 "perf: interrupt took too long (%lld > %lld), lowering "
513 "kernel.perf_event_max_sample_rate to %d\n",
514 __report_avg, __report_allowed,
515 sysctl_perf_event_sample_rate);
518 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
520 void perf_sample_event_took(u64 sample_len_ns)
522 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
530 /* Decay the counter by 1 average sample. */
531 running_len = __this_cpu_read(running_sample_length);
532 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
533 running_len += sample_len_ns;
534 __this_cpu_write(running_sample_length, running_len);
537 * Note: this will be biased artifically low until we have
538 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
539 * from having to maintain a count.
541 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
542 if (avg_len <= max_len)
545 __report_avg = avg_len;
546 __report_allowed = max_len;
549 * Compute a throttle threshold 25% below the current duration.
551 avg_len += avg_len / 4;
552 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
558 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
559 WRITE_ONCE(max_samples_per_tick, max);
561 sysctl_perf_event_sample_rate = max * HZ;
562 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
564 if (!irq_work_queue(&perf_duration_work)) {
565 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
566 "kernel.perf_event_max_sample_rate to %d\n",
567 __report_avg, __report_allowed,
568 sysctl_perf_event_sample_rate);
572 static atomic64_t perf_event_id;
574 static void update_context_time(struct perf_event_context *ctx);
575 static u64 perf_event_time(struct perf_event *event);
577 void __weak perf_event_print_debug(void) { }
579 static inline u64 perf_clock(void)
581 return local_clock();
584 static inline u64 perf_event_clock(struct perf_event *event)
586 return event->clock();
590 * State based event timekeeping...
592 * The basic idea is to use event->state to determine which (if any) time
593 * fields to increment with the current delta. This means we only need to
594 * update timestamps when we change state or when they are explicitly requested
597 * Event groups make things a little more complicated, but not terribly so. The
598 * rules for a group are that if the group leader is OFF the entire group is
599 * OFF, irrespecive of what the group member states are. This results in
600 * __perf_effective_state().
602 * A futher ramification is that when a group leader flips between OFF and
603 * !OFF, we need to update all group member times.
606 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
607 * need to make sure the relevant context time is updated before we try and
608 * update our timestamps.
611 static __always_inline enum perf_event_state
612 __perf_effective_state(struct perf_event *event)
614 struct perf_event *leader = event->group_leader;
616 if (leader->state <= PERF_EVENT_STATE_OFF)
617 return leader->state;
622 static __always_inline void
623 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
625 enum perf_event_state state = __perf_effective_state(event);
626 u64 delta = now - event->tstamp;
628 *enabled = event->total_time_enabled;
629 if (state >= PERF_EVENT_STATE_INACTIVE)
632 *running = event->total_time_running;
633 if (state >= PERF_EVENT_STATE_ACTIVE)
637 static void perf_event_update_time(struct perf_event *event)
639 u64 now = perf_event_time(event);
641 __perf_update_times(event, now, &event->total_time_enabled,
642 &event->total_time_running);
646 static void perf_event_update_sibling_time(struct perf_event *leader)
648 struct perf_event *sibling;
650 for_each_sibling_event(sibling, leader)
651 perf_event_update_time(sibling);
655 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
657 if (event->state == state)
660 perf_event_update_time(event);
662 * If a group leader gets enabled/disabled all its siblings
665 if ((event->state < 0) ^ (state < 0))
666 perf_event_update_sibling_time(event);
668 WRITE_ONCE(event->state, state);
672 * UP store-release, load-acquire
675 #define __store_release(ptr, val) \
678 WRITE_ONCE(*(ptr), (val)); \
681 #define __load_acquire(ptr) \
683 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \
688 static void perf_ctx_disable(struct perf_event_context *ctx, bool cgroup)
690 struct perf_event_pmu_context *pmu_ctx;
692 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
693 if (cgroup && !pmu_ctx->nr_cgroups)
695 perf_pmu_disable(pmu_ctx->pmu);
699 static void perf_ctx_enable(struct perf_event_context *ctx, bool cgroup)
701 struct perf_event_pmu_context *pmu_ctx;
703 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
704 if (cgroup && !pmu_ctx->nr_cgroups)
706 perf_pmu_enable(pmu_ctx->pmu);
710 static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type);
711 static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type);
713 #ifdef CONFIG_CGROUP_PERF
716 perf_cgroup_match(struct perf_event *event)
718 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
720 /* @event doesn't care about cgroup */
724 /* wants specific cgroup scope but @cpuctx isn't associated with any */
729 * Cgroup scoping is recursive. An event enabled for a cgroup is
730 * also enabled for all its descendant cgroups. If @cpuctx's
731 * cgroup is a descendant of @event's (the test covers identity
732 * case), it's a match.
734 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
735 event->cgrp->css.cgroup);
738 static inline void perf_detach_cgroup(struct perf_event *event)
740 css_put(&event->cgrp->css);
744 static inline int is_cgroup_event(struct perf_event *event)
746 return event->cgrp != NULL;
749 static inline u64 perf_cgroup_event_time(struct perf_event *event)
751 struct perf_cgroup_info *t;
753 t = per_cpu_ptr(event->cgrp->info, event->cpu);
757 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
759 struct perf_cgroup_info *t;
761 t = per_cpu_ptr(event->cgrp->info, event->cpu);
762 if (!__load_acquire(&t->active))
764 now += READ_ONCE(t->timeoffset);
768 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
771 info->time += now - info->timestamp;
772 info->timestamp = now;
774 * see update_context_time()
776 WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
779 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
781 struct perf_cgroup *cgrp = cpuctx->cgrp;
782 struct cgroup_subsys_state *css;
783 struct perf_cgroup_info *info;
786 u64 now = perf_clock();
788 for (css = &cgrp->css; css; css = css->parent) {
789 cgrp = container_of(css, struct perf_cgroup, css);
790 info = this_cpu_ptr(cgrp->info);
792 __update_cgrp_time(info, now, true);
794 __store_release(&info->active, 0);
799 static inline void update_cgrp_time_from_event(struct perf_event *event)
801 struct perf_cgroup_info *info;
804 * ensure we access cgroup data only when needed and
805 * when we know the cgroup is pinned (css_get)
807 if (!is_cgroup_event(event))
810 info = this_cpu_ptr(event->cgrp->info);
812 * Do not update time when cgroup is not active
815 __update_cgrp_time(info, perf_clock(), true);
819 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
821 struct perf_event_context *ctx = &cpuctx->ctx;
822 struct perf_cgroup *cgrp = cpuctx->cgrp;
823 struct perf_cgroup_info *info;
824 struct cgroup_subsys_state *css;
827 * ctx->lock held by caller
828 * ensure we do not access cgroup data
829 * unless we have the cgroup pinned (css_get)
834 WARN_ON_ONCE(!ctx->nr_cgroups);
836 for (css = &cgrp->css; css; css = css->parent) {
837 cgrp = container_of(css, struct perf_cgroup, css);
838 info = this_cpu_ptr(cgrp->info);
839 __update_cgrp_time(info, ctx->timestamp, false);
840 __store_release(&info->active, 1);
845 * reschedule events based on the cgroup constraint of task.
847 static void perf_cgroup_switch(struct task_struct *task)
849 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
850 struct perf_cgroup *cgrp;
853 * cpuctx->cgrp is set when the first cgroup event enabled,
854 * and is cleared when the last cgroup event disabled.
856 if (READ_ONCE(cpuctx->cgrp) == NULL)
859 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
861 cgrp = perf_cgroup_from_task(task, NULL);
862 if (READ_ONCE(cpuctx->cgrp) == cgrp)
865 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
866 perf_ctx_disable(&cpuctx->ctx, true);
868 ctx_sched_out(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP);
870 * must not be done before ctxswout due
871 * to update_cgrp_time_from_cpuctx() in
876 * set cgrp before ctxsw in to allow
877 * perf_cgroup_set_timestamp() in ctx_sched_in()
878 * to not have to pass task around
880 ctx_sched_in(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP);
882 perf_ctx_enable(&cpuctx->ctx, true);
883 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
886 static int perf_cgroup_ensure_storage(struct perf_event *event,
887 struct cgroup_subsys_state *css)
889 struct perf_cpu_context *cpuctx;
890 struct perf_event **storage;
891 int cpu, heap_size, ret = 0;
894 * Allow storage to have sufficent space for an iterator for each
895 * possibly nested cgroup plus an iterator for events with no cgroup.
897 for (heap_size = 1; css; css = css->parent)
900 for_each_possible_cpu(cpu) {
901 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
902 if (heap_size <= cpuctx->heap_size)
905 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
906 GFP_KERNEL, cpu_to_node(cpu));
912 raw_spin_lock_irq(&cpuctx->ctx.lock);
913 if (cpuctx->heap_size < heap_size) {
914 swap(cpuctx->heap, storage);
915 if (storage == cpuctx->heap_default)
917 cpuctx->heap_size = heap_size;
919 raw_spin_unlock_irq(&cpuctx->ctx.lock);
927 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
928 struct perf_event_attr *attr,
929 struct perf_event *group_leader)
931 struct perf_cgroup *cgrp;
932 struct cgroup_subsys_state *css;
933 struct fd f = fdget(fd);
939 css = css_tryget_online_from_dir(f.file->f_path.dentry,
940 &perf_event_cgrp_subsys);
946 ret = perf_cgroup_ensure_storage(event, css);
950 cgrp = container_of(css, struct perf_cgroup, css);
954 * all events in a group must monitor
955 * the same cgroup because a task belongs
956 * to only one perf cgroup at a time
958 if (group_leader && group_leader->cgrp != cgrp) {
959 perf_detach_cgroup(event);
968 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
970 struct perf_cpu_context *cpuctx;
972 if (!is_cgroup_event(event))
975 event->pmu_ctx->nr_cgroups++;
978 * Because cgroup events are always per-cpu events,
979 * @ctx == &cpuctx->ctx.
981 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
983 if (ctx->nr_cgroups++)
986 cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
990 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
992 struct perf_cpu_context *cpuctx;
994 if (!is_cgroup_event(event))
997 event->pmu_ctx->nr_cgroups--;
1000 * Because cgroup events are always per-cpu events,
1001 * @ctx == &cpuctx->ctx.
1003 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1005 if (--ctx->nr_cgroups)
1008 cpuctx->cgrp = NULL;
1011 #else /* !CONFIG_CGROUP_PERF */
1014 perf_cgroup_match(struct perf_event *event)
1019 static inline void perf_detach_cgroup(struct perf_event *event)
1022 static inline int is_cgroup_event(struct perf_event *event)
1027 static inline void update_cgrp_time_from_event(struct perf_event *event)
1031 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1036 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1037 struct perf_event_attr *attr,
1038 struct perf_event *group_leader)
1044 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
1048 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1053 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1059 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1064 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1068 static void perf_cgroup_switch(struct task_struct *task)
1074 * set default to be dependent on timer tick just
1075 * like original code
1077 #define PERF_CPU_HRTIMER (1000 / HZ)
1079 * function must be called with interrupts disabled
1081 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1083 struct perf_cpu_pmu_context *cpc;
1086 lockdep_assert_irqs_disabled();
1088 cpc = container_of(hr, struct perf_cpu_pmu_context, hrtimer);
1089 rotations = perf_rotate_context(cpc);
1091 raw_spin_lock(&cpc->hrtimer_lock);
1093 hrtimer_forward_now(hr, cpc->hrtimer_interval);
1095 cpc->hrtimer_active = 0;
1096 raw_spin_unlock(&cpc->hrtimer_lock);
1098 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1101 static void __perf_mux_hrtimer_init(struct perf_cpu_pmu_context *cpc, int cpu)
1103 struct hrtimer *timer = &cpc->hrtimer;
1104 struct pmu *pmu = cpc->epc.pmu;
1108 * check default is sane, if not set then force to
1109 * default interval (1/tick)
1111 interval = pmu->hrtimer_interval_ms;
1113 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1115 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1117 raw_spin_lock_init(&cpc->hrtimer_lock);
1118 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1119 timer->function = perf_mux_hrtimer_handler;
1122 static int perf_mux_hrtimer_restart(struct perf_cpu_pmu_context *cpc)
1124 struct hrtimer *timer = &cpc->hrtimer;
1125 unsigned long flags;
1127 raw_spin_lock_irqsave(&cpc->hrtimer_lock, flags);
1128 if (!cpc->hrtimer_active) {
1129 cpc->hrtimer_active = 1;
1130 hrtimer_forward_now(timer, cpc->hrtimer_interval);
1131 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1133 raw_spin_unlock_irqrestore(&cpc->hrtimer_lock, flags);
1138 static int perf_mux_hrtimer_restart_ipi(void *arg)
1140 return perf_mux_hrtimer_restart(arg);
1143 void perf_pmu_disable(struct pmu *pmu)
1145 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1147 pmu->pmu_disable(pmu);
1150 void perf_pmu_enable(struct pmu *pmu)
1152 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1154 pmu->pmu_enable(pmu);
1157 static void perf_assert_pmu_disabled(struct pmu *pmu)
1159 WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0);
1162 static void get_ctx(struct perf_event_context *ctx)
1164 refcount_inc(&ctx->refcount);
1167 static void *alloc_task_ctx_data(struct pmu *pmu)
1169 if (pmu->task_ctx_cache)
1170 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1175 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1177 if (pmu->task_ctx_cache && task_ctx_data)
1178 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1181 static void free_ctx(struct rcu_head *head)
1183 struct perf_event_context *ctx;
1185 ctx = container_of(head, struct perf_event_context, rcu_head);
1189 static void put_ctx(struct perf_event_context *ctx)
1191 if (refcount_dec_and_test(&ctx->refcount)) {
1192 if (ctx->parent_ctx)
1193 put_ctx(ctx->parent_ctx);
1194 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1195 put_task_struct(ctx->task);
1196 call_rcu(&ctx->rcu_head, free_ctx);
1201 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1202 * perf_pmu_migrate_context() we need some magic.
1204 * Those places that change perf_event::ctx will hold both
1205 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1207 * Lock ordering is by mutex address. There are two other sites where
1208 * perf_event_context::mutex nests and those are:
1210 * - perf_event_exit_task_context() [ child , 0 ]
1211 * perf_event_exit_event()
1212 * put_event() [ parent, 1 ]
1214 * - perf_event_init_context() [ parent, 0 ]
1215 * inherit_task_group()
1218 * perf_event_alloc()
1220 * perf_try_init_event() [ child , 1 ]
1222 * While it appears there is an obvious deadlock here -- the parent and child
1223 * nesting levels are inverted between the two. This is in fact safe because
1224 * life-time rules separate them. That is an exiting task cannot fork, and a
1225 * spawning task cannot (yet) exit.
1227 * But remember that these are parent<->child context relations, and
1228 * migration does not affect children, therefore these two orderings should not
1231 * The change in perf_event::ctx does not affect children (as claimed above)
1232 * because the sys_perf_event_open() case will install a new event and break
1233 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1234 * concerned with cpuctx and that doesn't have children.
1236 * The places that change perf_event::ctx will issue:
1238 * perf_remove_from_context();
1239 * synchronize_rcu();
1240 * perf_install_in_context();
1242 * to affect the change. The remove_from_context() + synchronize_rcu() should
1243 * quiesce the event, after which we can install it in the new location. This
1244 * means that only external vectors (perf_fops, prctl) can perturb the event
1245 * while in transit. Therefore all such accessors should also acquire
1246 * perf_event_context::mutex to serialize against this.
1248 * However; because event->ctx can change while we're waiting to acquire
1249 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1254 * task_struct::perf_event_mutex
1255 * perf_event_context::mutex
1256 * perf_event::child_mutex;
1257 * perf_event_context::lock
1258 * perf_event::mmap_mutex
1260 * perf_addr_filters_head::lock
1264 * cpuctx->mutex / perf_event_context::mutex
1266 static struct perf_event_context *
1267 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1269 struct perf_event_context *ctx;
1273 ctx = READ_ONCE(event->ctx);
1274 if (!refcount_inc_not_zero(&ctx->refcount)) {
1280 mutex_lock_nested(&ctx->mutex, nesting);
1281 if (event->ctx != ctx) {
1282 mutex_unlock(&ctx->mutex);
1290 static inline struct perf_event_context *
1291 perf_event_ctx_lock(struct perf_event *event)
1293 return perf_event_ctx_lock_nested(event, 0);
1296 static void perf_event_ctx_unlock(struct perf_event *event,
1297 struct perf_event_context *ctx)
1299 mutex_unlock(&ctx->mutex);
1304 * This must be done under the ctx->lock, such as to serialize against
1305 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1306 * calling scheduler related locks and ctx->lock nests inside those.
1308 static __must_check struct perf_event_context *
1309 unclone_ctx(struct perf_event_context *ctx)
1311 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1313 lockdep_assert_held(&ctx->lock);
1316 ctx->parent_ctx = NULL;
1322 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1327 * only top level events have the pid namespace they were created in
1330 event = event->parent;
1332 nr = __task_pid_nr_ns(p, type, event->ns);
1333 /* avoid -1 if it is idle thread or runs in another ns */
1334 if (!nr && !pid_alive(p))
1339 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1341 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1344 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1346 return perf_event_pid_type(event, p, PIDTYPE_PID);
1350 * If we inherit events we want to return the parent event id
1353 static u64 primary_event_id(struct perf_event *event)
1358 id = event->parent->id;
1364 * Get the perf_event_context for a task and lock it.
1366 * This has to cope with the fact that until it is locked,
1367 * the context could get moved to another task.
1369 static struct perf_event_context *
1370 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
1372 struct perf_event_context *ctx;
1376 * One of the few rules of preemptible RCU is that one cannot do
1377 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1378 * part of the read side critical section was irqs-enabled -- see
1379 * rcu_read_unlock_special().
1381 * Since ctx->lock nests under rq->lock we must ensure the entire read
1382 * side critical section has interrupts disabled.
1384 local_irq_save(*flags);
1386 ctx = rcu_dereference(task->perf_event_ctxp);
1389 * If this context is a clone of another, it might
1390 * get swapped for another underneath us by
1391 * perf_event_task_sched_out, though the
1392 * rcu_read_lock() protects us from any context
1393 * getting freed. Lock the context and check if it
1394 * got swapped before we could get the lock, and retry
1395 * if so. If we locked the right context, then it
1396 * can't get swapped on us any more.
1398 raw_spin_lock(&ctx->lock);
1399 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
1400 raw_spin_unlock(&ctx->lock);
1402 local_irq_restore(*flags);
1406 if (ctx->task == TASK_TOMBSTONE ||
1407 !refcount_inc_not_zero(&ctx->refcount)) {
1408 raw_spin_unlock(&ctx->lock);
1411 WARN_ON_ONCE(ctx->task != task);
1416 local_irq_restore(*flags);
1421 * Get the context for a task and increment its pin_count so it
1422 * can't get swapped to another task. This also increments its
1423 * reference count so that the context can't get freed.
1425 static struct perf_event_context *
1426 perf_pin_task_context(struct task_struct *task)
1428 struct perf_event_context *ctx;
1429 unsigned long flags;
1431 ctx = perf_lock_task_context(task, &flags);
1434 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1439 static void perf_unpin_context(struct perf_event_context *ctx)
1441 unsigned long flags;
1443 raw_spin_lock_irqsave(&ctx->lock, flags);
1445 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1449 * Update the record of the current time in a context.
1451 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1453 u64 now = perf_clock();
1455 lockdep_assert_held(&ctx->lock);
1458 ctx->time += now - ctx->timestamp;
1459 ctx->timestamp = now;
1462 * The above: time' = time + (now - timestamp), can be re-arranged
1463 * into: time` = now + (time - timestamp), which gives a single value
1464 * offset to compute future time without locks on.
1466 * See perf_event_time_now(), which can be used from NMI context where
1467 * it's (obviously) not possible to acquire ctx->lock in order to read
1468 * both the above values in a consistent manner.
1470 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1473 static void update_context_time(struct perf_event_context *ctx)
1475 __update_context_time(ctx, true);
1478 static u64 perf_event_time(struct perf_event *event)
1480 struct perf_event_context *ctx = event->ctx;
1485 if (is_cgroup_event(event))
1486 return perf_cgroup_event_time(event);
1491 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1493 struct perf_event_context *ctx = event->ctx;
1498 if (is_cgroup_event(event))
1499 return perf_cgroup_event_time_now(event, now);
1501 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1504 now += READ_ONCE(ctx->timeoffset);
1508 static enum event_type_t get_event_type(struct perf_event *event)
1510 struct perf_event_context *ctx = event->ctx;
1511 enum event_type_t event_type;
1513 lockdep_assert_held(&ctx->lock);
1516 * It's 'group type', really, because if our group leader is
1517 * pinned, so are we.
1519 if (event->group_leader != event)
1520 event = event->group_leader;
1522 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1524 event_type |= EVENT_CPU;
1530 * Helper function to initialize event group nodes.
1532 static void init_event_group(struct perf_event *event)
1534 RB_CLEAR_NODE(&event->group_node);
1535 event->group_index = 0;
1539 * Extract pinned or flexible groups from the context
1540 * based on event attrs bits.
1542 static struct perf_event_groups *
1543 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1545 if (event->attr.pinned)
1546 return &ctx->pinned_groups;
1548 return &ctx->flexible_groups;
1552 * Helper function to initializes perf_event_group trees.
1554 static void perf_event_groups_init(struct perf_event_groups *groups)
1556 groups->tree = RB_ROOT;
1560 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1562 struct cgroup *cgroup = NULL;
1564 #ifdef CONFIG_CGROUP_PERF
1566 cgroup = event->cgrp->css.cgroup;
1573 * Compare function for event groups;
1575 * Implements complex key that first sorts by CPU and then by virtual index
1576 * which provides ordering when rotating groups for the same CPU.
1578 static __always_inline int
1579 perf_event_groups_cmp(const int left_cpu, const struct pmu *left_pmu,
1580 const struct cgroup *left_cgroup, const u64 left_group_index,
1581 const struct perf_event *right)
1583 if (left_cpu < right->cpu)
1585 if (left_cpu > right->cpu)
1589 if (left_pmu < right->pmu_ctx->pmu)
1591 if (left_pmu > right->pmu_ctx->pmu)
1595 #ifdef CONFIG_CGROUP_PERF
1597 const struct cgroup *right_cgroup = event_cgroup(right);
1599 if (left_cgroup != right_cgroup) {
1602 * Left has no cgroup but right does, no
1603 * cgroups come first.
1607 if (!right_cgroup) {
1609 * Right has no cgroup but left does, no
1610 * cgroups come first.
1614 /* Two dissimilar cgroups, order by id. */
1615 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1623 if (left_group_index < right->group_index)
1625 if (left_group_index > right->group_index)
1631 #define __node_2_pe(node) \
1632 rb_entry((node), struct perf_event, group_node)
1634 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1636 struct perf_event *e = __node_2_pe(a);
1637 return perf_event_groups_cmp(e->cpu, e->pmu_ctx->pmu, event_cgroup(e),
1638 e->group_index, __node_2_pe(b)) < 0;
1641 struct __group_key {
1644 struct cgroup *cgroup;
1647 static inline int __group_cmp(const void *key, const struct rb_node *node)
1649 const struct __group_key *a = key;
1650 const struct perf_event *b = __node_2_pe(node);
1652 /* partial/subtree match: @cpu, @pmu, @cgroup; ignore: @group_index */
1653 return perf_event_groups_cmp(a->cpu, a->pmu, a->cgroup, b->group_index, b);
1657 __group_cmp_ignore_cgroup(const void *key, const struct rb_node *node)
1659 const struct __group_key *a = key;
1660 const struct perf_event *b = __node_2_pe(node);
1662 /* partial/subtree match: @cpu, @pmu, ignore: @cgroup, @group_index */
1663 return perf_event_groups_cmp(a->cpu, a->pmu, event_cgroup(b),
1668 * Insert @event into @groups' tree; using
1669 * {@event->cpu, @event->pmu_ctx->pmu, event_cgroup(@event), ++@groups->index}
1670 * as key. This places it last inside the {cpu,pmu,cgroup} subtree.
1673 perf_event_groups_insert(struct perf_event_groups *groups,
1674 struct perf_event *event)
1676 event->group_index = ++groups->index;
1678 rb_add(&event->group_node, &groups->tree, __group_less);
1682 * Helper function to insert event into the pinned or flexible groups.
1685 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1687 struct perf_event_groups *groups;
1689 groups = get_event_groups(event, ctx);
1690 perf_event_groups_insert(groups, event);
1694 * Delete a group from a tree.
1697 perf_event_groups_delete(struct perf_event_groups *groups,
1698 struct perf_event *event)
1700 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1701 RB_EMPTY_ROOT(&groups->tree));
1703 rb_erase(&event->group_node, &groups->tree);
1704 init_event_group(event);
1708 * Helper function to delete event from its groups.
1711 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1713 struct perf_event_groups *groups;
1715 groups = get_event_groups(event, ctx);
1716 perf_event_groups_delete(groups, event);
1720 * Get the leftmost event in the {cpu,pmu,cgroup} subtree.
1722 static struct perf_event *
1723 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1724 struct pmu *pmu, struct cgroup *cgrp)
1726 struct __group_key key = {
1731 struct rb_node *node;
1733 node = rb_find_first(&key, &groups->tree, __group_cmp);
1735 return __node_2_pe(node);
1740 static struct perf_event *
1741 perf_event_groups_next(struct perf_event *event, struct pmu *pmu)
1743 struct __group_key key = {
1746 .cgroup = event_cgroup(event),
1748 struct rb_node *next;
1750 next = rb_next_match(&key, &event->group_node, __group_cmp);
1752 return __node_2_pe(next);
1757 #define perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) \
1758 for (event = perf_event_groups_first(groups, cpu, pmu, NULL); \
1759 event; event = perf_event_groups_next(event, pmu))
1762 * Iterate through the whole groups tree.
1764 #define perf_event_groups_for_each(event, groups) \
1765 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1766 typeof(*event), group_node); event; \
1767 event = rb_entry_safe(rb_next(&event->group_node), \
1768 typeof(*event), group_node))
1771 * Add an event from the lists for its context.
1772 * Must be called with ctx->mutex and ctx->lock held.
1775 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1777 lockdep_assert_held(&ctx->lock);
1779 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1780 event->attach_state |= PERF_ATTACH_CONTEXT;
1782 event->tstamp = perf_event_time(event);
1785 * If we're a stand alone event or group leader, we go to the context
1786 * list, group events are kept attached to the group so that
1787 * perf_group_detach can, at all times, locate all siblings.
1789 if (event->group_leader == event) {
1790 event->group_caps = event->event_caps;
1791 add_event_to_groups(event, ctx);
1794 list_add_rcu(&event->event_entry, &ctx->event_list);
1796 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1798 if (event->attr.inherit_stat)
1801 if (event->state > PERF_EVENT_STATE_OFF)
1802 perf_cgroup_event_enable(event, ctx);
1805 event->pmu_ctx->nr_events++;
1809 * Initialize event state based on the perf_event_attr::disabled.
1811 static inline void perf_event__state_init(struct perf_event *event)
1813 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1814 PERF_EVENT_STATE_INACTIVE;
1817 static int __perf_event_read_size(u64 read_format, int nr_siblings)
1819 int entry = sizeof(u64); /* value */
1823 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1824 size += sizeof(u64);
1826 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1827 size += sizeof(u64);
1829 if (read_format & PERF_FORMAT_ID)
1830 entry += sizeof(u64);
1832 if (read_format & PERF_FORMAT_LOST)
1833 entry += sizeof(u64);
1835 if (read_format & PERF_FORMAT_GROUP) {
1837 size += sizeof(u64);
1841 * Since perf_event_validate_size() limits this to 16k and inhibits
1842 * adding more siblings, this will never overflow.
1844 return size + nr * entry;
1847 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1849 struct perf_sample_data *data;
1852 if (sample_type & PERF_SAMPLE_IP)
1853 size += sizeof(data->ip);
1855 if (sample_type & PERF_SAMPLE_ADDR)
1856 size += sizeof(data->addr);
1858 if (sample_type & PERF_SAMPLE_PERIOD)
1859 size += sizeof(data->period);
1861 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1862 size += sizeof(data->weight.full);
1864 if (sample_type & PERF_SAMPLE_READ)
1865 size += event->read_size;
1867 if (sample_type & PERF_SAMPLE_DATA_SRC)
1868 size += sizeof(data->data_src.val);
1870 if (sample_type & PERF_SAMPLE_TRANSACTION)
1871 size += sizeof(data->txn);
1873 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1874 size += sizeof(data->phys_addr);
1876 if (sample_type & PERF_SAMPLE_CGROUP)
1877 size += sizeof(data->cgroup);
1879 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1880 size += sizeof(data->data_page_size);
1882 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1883 size += sizeof(data->code_page_size);
1885 event->header_size = size;
1889 * Called at perf_event creation and when events are attached/detached from a
1892 static void perf_event__header_size(struct perf_event *event)
1895 __perf_event_read_size(event->attr.read_format,
1896 event->group_leader->nr_siblings);
1897 __perf_event_header_size(event, event->attr.sample_type);
1900 static void perf_event__id_header_size(struct perf_event *event)
1902 struct perf_sample_data *data;
1903 u64 sample_type = event->attr.sample_type;
1906 if (sample_type & PERF_SAMPLE_TID)
1907 size += sizeof(data->tid_entry);
1909 if (sample_type & PERF_SAMPLE_TIME)
1910 size += sizeof(data->time);
1912 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1913 size += sizeof(data->id);
1915 if (sample_type & PERF_SAMPLE_ID)
1916 size += sizeof(data->id);
1918 if (sample_type & PERF_SAMPLE_STREAM_ID)
1919 size += sizeof(data->stream_id);
1921 if (sample_type & PERF_SAMPLE_CPU)
1922 size += sizeof(data->cpu_entry);
1924 event->id_header_size = size;
1928 * Check that adding an event to the group does not result in anybody
1929 * overflowing the 64k event limit imposed by the output buffer.
1931 * Specifically, check that the read_size for the event does not exceed 16k,
1932 * read_size being the one term that grows with groups size. Since read_size
1933 * depends on per-event read_format, also (re)check the existing events.
1935 * This leaves 48k for the constant size fields and things like callchains,
1936 * branch stacks and register sets.
1938 static bool perf_event_validate_size(struct perf_event *event)
1940 struct perf_event *sibling, *group_leader = event->group_leader;
1942 if (__perf_event_read_size(event->attr.read_format,
1943 group_leader->nr_siblings + 1) > 16*1024)
1946 if (__perf_event_read_size(group_leader->attr.read_format,
1947 group_leader->nr_siblings + 1) > 16*1024)
1951 * When creating a new group leader, group_leader->ctx is initialized
1952 * after the size has been validated, but we cannot safely use
1953 * for_each_sibling_event() until group_leader->ctx is set. A new group
1954 * leader cannot have any siblings yet, so we can safely skip checking
1955 * the non-existent siblings.
1957 if (event == group_leader)
1960 for_each_sibling_event(sibling, group_leader) {
1961 if (__perf_event_read_size(sibling->attr.read_format,
1962 group_leader->nr_siblings + 1) > 16*1024)
1969 static void perf_group_attach(struct perf_event *event)
1971 struct perf_event *group_leader = event->group_leader, *pos;
1973 lockdep_assert_held(&event->ctx->lock);
1976 * We can have double attach due to group movement (move_group) in
1977 * perf_event_open().
1979 if (event->attach_state & PERF_ATTACH_GROUP)
1982 event->attach_state |= PERF_ATTACH_GROUP;
1984 if (group_leader == event)
1987 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1989 group_leader->group_caps &= event->event_caps;
1991 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1992 group_leader->nr_siblings++;
1993 group_leader->group_generation++;
1995 perf_event__header_size(group_leader);
1997 for_each_sibling_event(pos, group_leader)
1998 perf_event__header_size(pos);
2002 * Remove an event from the lists for its context.
2003 * Must be called with ctx->mutex and ctx->lock held.
2006 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
2008 WARN_ON_ONCE(event->ctx != ctx);
2009 lockdep_assert_held(&ctx->lock);
2012 * We can have double detach due to exit/hot-unplug + close.
2014 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
2017 event->attach_state &= ~PERF_ATTACH_CONTEXT;
2020 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
2022 if (event->attr.inherit_stat)
2025 list_del_rcu(&event->event_entry);
2027 if (event->group_leader == event)
2028 del_event_from_groups(event, ctx);
2031 * If event was in error state, then keep it
2032 * that way, otherwise bogus counts will be
2033 * returned on read(). The only way to get out
2034 * of error state is by explicit re-enabling
2037 if (event->state > PERF_EVENT_STATE_OFF) {
2038 perf_cgroup_event_disable(event, ctx);
2039 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2043 event->pmu_ctx->nr_events--;
2047 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2049 if (!has_aux(aux_event))
2052 if (!event->pmu->aux_output_match)
2055 return event->pmu->aux_output_match(aux_event);
2058 static void put_event(struct perf_event *event);
2059 static void event_sched_out(struct perf_event *event,
2060 struct perf_event_context *ctx);
2062 static void perf_put_aux_event(struct perf_event *event)
2064 struct perf_event_context *ctx = event->ctx;
2065 struct perf_event *iter;
2068 * If event uses aux_event tear down the link
2070 if (event->aux_event) {
2071 iter = event->aux_event;
2072 event->aux_event = NULL;
2078 * If the event is an aux_event, tear down all links to
2079 * it from other events.
2081 for_each_sibling_event(iter, event->group_leader) {
2082 if (iter->aux_event != event)
2085 iter->aux_event = NULL;
2089 * If it's ACTIVE, schedule it out and put it into ERROR
2090 * state so that we don't try to schedule it again. Note
2091 * that perf_event_enable() will clear the ERROR status.
2093 event_sched_out(iter, ctx);
2094 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2098 static bool perf_need_aux_event(struct perf_event *event)
2100 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2103 static int perf_get_aux_event(struct perf_event *event,
2104 struct perf_event *group_leader)
2107 * Our group leader must be an aux event if we want to be
2108 * an aux_output. This way, the aux event will precede its
2109 * aux_output events in the group, and therefore will always
2116 * aux_output and aux_sample_size are mutually exclusive.
2118 if (event->attr.aux_output && event->attr.aux_sample_size)
2121 if (event->attr.aux_output &&
2122 !perf_aux_output_match(event, group_leader))
2125 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2128 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2132 * Link aux_outputs to their aux event; this is undone in
2133 * perf_group_detach() by perf_put_aux_event(). When the
2134 * group in torn down, the aux_output events loose their
2135 * link to the aux_event and can't schedule any more.
2137 event->aux_event = group_leader;
2142 static inline struct list_head *get_event_list(struct perf_event *event)
2144 return event->attr.pinned ? &event->pmu_ctx->pinned_active :
2145 &event->pmu_ctx->flexible_active;
2149 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2150 * cannot exist on their own, schedule them out and move them into the ERROR
2151 * state. Also see _perf_event_enable(), it will not be able to recover
2154 static inline void perf_remove_sibling_event(struct perf_event *event)
2156 event_sched_out(event, event->ctx);
2157 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2160 static void perf_group_detach(struct perf_event *event)
2162 struct perf_event *leader = event->group_leader;
2163 struct perf_event *sibling, *tmp;
2164 struct perf_event_context *ctx = event->ctx;
2166 lockdep_assert_held(&ctx->lock);
2169 * We can have double detach due to exit/hot-unplug + close.
2171 if (!(event->attach_state & PERF_ATTACH_GROUP))
2174 event->attach_state &= ~PERF_ATTACH_GROUP;
2176 perf_put_aux_event(event);
2179 * If this is a sibling, remove it from its group.
2181 if (leader != event) {
2182 list_del_init(&event->sibling_list);
2183 event->group_leader->nr_siblings--;
2184 event->group_leader->group_generation++;
2189 * If this was a group event with sibling events then
2190 * upgrade the siblings to singleton events by adding them
2191 * to whatever list we are on.
2193 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2195 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2196 perf_remove_sibling_event(sibling);
2198 sibling->group_leader = sibling;
2199 list_del_init(&sibling->sibling_list);
2201 /* Inherit group flags from the previous leader */
2202 sibling->group_caps = event->group_caps;
2204 if (sibling->attach_state & PERF_ATTACH_CONTEXT) {
2205 add_event_to_groups(sibling, event->ctx);
2207 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2208 list_add_tail(&sibling->active_list, get_event_list(sibling));
2211 WARN_ON_ONCE(sibling->ctx != event->ctx);
2215 for_each_sibling_event(tmp, leader)
2216 perf_event__header_size(tmp);
2218 perf_event__header_size(leader);
2221 static void sync_child_event(struct perf_event *child_event);
2223 static void perf_child_detach(struct perf_event *event)
2225 struct perf_event *parent_event = event->parent;
2227 if (!(event->attach_state & PERF_ATTACH_CHILD))
2230 event->attach_state &= ~PERF_ATTACH_CHILD;
2232 if (WARN_ON_ONCE(!parent_event))
2235 lockdep_assert_held(&parent_event->child_mutex);
2237 sync_child_event(event);
2238 list_del_init(&event->child_list);
2241 static bool is_orphaned_event(struct perf_event *event)
2243 return event->state == PERF_EVENT_STATE_DEAD;
2247 event_filter_match(struct perf_event *event)
2249 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2250 perf_cgroup_match(event);
2254 event_sched_out(struct perf_event *event, struct perf_event_context *ctx)
2256 struct perf_event_pmu_context *epc = event->pmu_ctx;
2257 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2258 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2260 // XXX cpc serialization, probably per-cpu IRQ disabled
2262 WARN_ON_ONCE(event->ctx != ctx);
2263 lockdep_assert_held(&ctx->lock);
2265 if (event->state != PERF_EVENT_STATE_ACTIVE)
2269 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2270 * we can schedule events _OUT_ individually through things like
2271 * __perf_remove_from_context().
2273 list_del_init(&event->active_list);
2275 perf_pmu_disable(event->pmu);
2277 event->pmu->del(event, 0);
2280 if (event->pending_disable) {
2281 event->pending_disable = 0;
2282 perf_cgroup_event_disable(event, ctx);
2283 state = PERF_EVENT_STATE_OFF;
2286 if (event->pending_sigtrap) {
2289 event->pending_sigtrap = 0;
2290 if (state != PERF_EVENT_STATE_OFF &&
2291 !event->pending_work) {
2292 event->pending_work = 1;
2294 WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount));
2295 task_work_add(current, &event->pending_task, TWA_RESUME);
2298 local_dec(&event->ctx->nr_pending);
2301 perf_event_set_state(event, state);
2303 if (!is_software_event(event))
2304 cpc->active_oncpu--;
2305 if (event->attr.freq && event->attr.sample_freq)
2307 if (event->attr.exclusive || !cpc->active_oncpu)
2310 perf_pmu_enable(event->pmu);
2314 group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx)
2316 struct perf_event *event;
2318 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2321 perf_assert_pmu_disabled(group_event->pmu_ctx->pmu);
2323 event_sched_out(group_event, ctx);
2326 * Schedule out siblings (if any):
2328 for_each_sibling_event(event, group_event)
2329 event_sched_out(event, ctx);
2332 #define DETACH_GROUP 0x01UL
2333 #define DETACH_CHILD 0x02UL
2334 #define DETACH_DEAD 0x04UL
2337 * Cross CPU call to remove a performance event
2339 * We disable the event on the hardware level first. After that we
2340 * remove it from the context list.
2343 __perf_remove_from_context(struct perf_event *event,
2344 struct perf_cpu_context *cpuctx,
2345 struct perf_event_context *ctx,
2348 struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
2349 unsigned long flags = (unsigned long)info;
2351 if (ctx->is_active & EVENT_TIME) {
2352 update_context_time(ctx);
2353 update_cgrp_time_from_cpuctx(cpuctx, false);
2357 * Ensure event_sched_out() switches to OFF, at the very least
2358 * this avoids raising perf_pending_task() at this time.
2360 if (flags & DETACH_DEAD)
2361 event->pending_disable = 1;
2362 event_sched_out(event, ctx);
2363 if (flags & DETACH_GROUP)
2364 perf_group_detach(event);
2365 if (flags & DETACH_CHILD)
2366 perf_child_detach(event);
2367 list_del_event(event, ctx);
2368 if (flags & DETACH_DEAD)
2369 event->state = PERF_EVENT_STATE_DEAD;
2371 if (!pmu_ctx->nr_events) {
2372 pmu_ctx->rotate_necessary = 0;
2374 if (ctx->task && ctx->is_active) {
2375 struct perf_cpu_pmu_context *cpc;
2377 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
2378 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
2379 cpc->task_epc = NULL;
2383 if (!ctx->nr_events && ctx->is_active) {
2384 if (ctx == &cpuctx->ctx)
2385 update_cgrp_time_from_cpuctx(cpuctx, true);
2389 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2390 cpuctx->task_ctx = NULL;
2396 * Remove the event from a task's (or a CPU's) list of events.
2398 * If event->ctx is a cloned context, callers must make sure that
2399 * every task struct that event->ctx->task could possibly point to
2400 * remains valid. This is OK when called from perf_release since
2401 * that only calls us on the top-level context, which can't be a clone.
2402 * When called from perf_event_exit_task, it's OK because the
2403 * context has been detached from its task.
2405 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2407 struct perf_event_context *ctx = event->ctx;
2409 lockdep_assert_held(&ctx->mutex);
2412 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2413 * to work in the face of TASK_TOMBSTONE, unlike every other
2414 * event_function_call() user.
2416 raw_spin_lock_irq(&ctx->lock);
2417 if (!ctx->is_active) {
2418 __perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context),
2419 ctx, (void *)flags);
2420 raw_spin_unlock_irq(&ctx->lock);
2423 raw_spin_unlock_irq(&ctx->lock);
2425 event_function_call(event, __perf_remove_from_context, (void *)flags);
2429 * Cross CPU call to disable a performance event
2431 static void __perf_event_disable(struct perf_event *event,
2432 struct perf_cpu_context *cpuctx,
2433 struct perf_event_context *ctx,
2436 if (event->state < PERF_EVENT_STATE_INACTIVE)
2439 if (ctx->is_active & EVENT_TIME) {
2440 update_context_time(ctx);
2441 update_cgrp_time_from_event(event);
2444 perf_pmu_disable(event->pmu_ctx->pmu);
2446 if (event == event->group_leader)
2447 group_sched_out(event, ctx);
2449 event_sched_out(event, ctx);
2451 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2452 perf_cgroup_event_disable(event, ctx);
2454 perf_pmu_enable(event->pmu_ctx->pmu);
2460 * If event->ctx is a cloned context, callers must make sure that
2461 * every task struct that event->ctx->task could possibly point to
2462 * remains valid. This condition is satisfied when called through
2463 * perf_event_for_each_child or perf_event_for_each because they
2464 * hold the top-level event's child_mutex, so any descendant that
2465 * goes to exit will block in perf_event_exit_event().
2467 * When called from perf_pending_irq it's OK because event->ctx
2468 * is the current context on this CPU and preemption is disabled,
2469 * hence we can't get into perf_event_task_sched_out for this context.
2471 static void _perf_event_disable(struct perf_event *event)
2473 struct perf_event_context *ctx = event->ctx;
2475 raw_spin_lock_irq(&ctx->lock);
2476 if (event->state <= PERF_EVENT_STATE_OFF) {
2477 raw_spin_unlock_irq(&ctx->lock);
2480 raw_spin_unlock_irq(&ctx->lock);
2482 event_function_call(event, __perf_event_disable, NULL);
2485 void perf_event_disable_local(struct perf_event *event)
2487 event_function_local(event, __perf_event_disable, NULL);
2491 * Strictly speaking kernel users cannot create groups and therefore this
2492 * interface does not need the perf_event_ctx_lock() magic.
2494 void perf_event_disable(struct perf_event *event)
2496 struct perf_event_context *ctx;
2498 ctx = perf_event_ctx_lock(event);
2499 _perf_event_disable(event);
2500 perf_event_ctx_unlock(event, ctx);
2502 EXPORT_SYMBOL_GPL(perf_event_disable);
2504 void perf_event_disable_inatomic(struct perf_event *event)
2506 event->pending_disable = 1;
2507 irq_work_queue(&event->pending_irq);
2510 #define MAX_INTERRUPTS (~0ULL)
2512 static void perf_log_throttle(struct perf_event *event, int enable);
2513 static void perf_log_itrace_start(struct perf_event *event);
2516 event_sched_in(struct perf_event *event, struct perf_event_context *ctx)
2518 struct perf_event_pmu_context *epc = event->pmu_ctx;
2519 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2522 WARN_ON_ONCE(event->ctx != ctx);
2524 lockdep_assert_held(&ctx->lock);
2526 if (event->state <= PERF_EVENT_STATE_OFF)
2529 WRITE_ONCE(event->oncpu, smp_processor_id());
2531 * Order event::oncpu write to happen before the ACTIVE state is
2532 * visible. This allows perf_event_{stop,read}() to observe the correct
2533 * ->oncpu if it sees ACTIVE.
2536 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2539 * Unthrottle events, since we scheduled we might have missed several
2540 * ticks already, also for a heavily scheduling task there is little
2541 * guarantee it'll get a tick in a timely manner.
2543 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2544 perf_log_throttle(event, 1);
2545 event->hw.interrupts = 0;
2548 perf_pmu_disable(event->pmu);
2550 perf_log_itrace_start(event);
2552 if (event->pmu->add(event, PERF_EF_START)) {
2553 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2559 if (!is_software_event(event))
2560 cpc->active_oncpu++;
2561 if (event->attr.freq && event->attr.sample_freq)
2564 if (event->attr.exclusive)
2568 perf_pmu_enable(event->pmu);
2574 group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx)
2576 struct perf_event *event, *partial_group = NULL;
2577 struct pmu *pmu = group_event->pmu_ctx->pmu;
2579 if (group_event->state == PERF_EVENT_STATE_OFF)
2582 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2584 if (event_sched_in(group_event, ctx))
2588 * Schedule in siblings as one group (if any):
2590 for_each_sibling_event(event, group_event) {
2591 if (event_sched_in(event, ctx)) {
2592 partial_group = event;
2597 if (!pmu->commit_txn(pmu))
2602 * Groups can be scheduled in as one unit only, so undo any
2603 * partial group before returning:
2604 * The events up to the failed event are scheduled out normally.
2606 for_each_sibling_event(event, group_event) {
2607 if (event == partial_group)
2610 event_sched_out(event, ctx);
2612 event_sched_out(group_event, ctx);
2615 pmu->cancel_txn(pmu);
2620 * Work out whether we can put this event group on the CPU now.
2622 static int group_can_go_on(struct perf_event *event, int can_add_hw)
2624 struct perf_event_pmu_context *epc = event->pmu_ctx;
2625 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2628 * Groups consisting entirely of software events can always go on.
2630 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2633 * If an exclusive group is already on, no other hardware
2639 * If this group is exclusive and there are already
2640 * events on the CPU, it can't go on.
2642 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2645 * Otherwise, try to add it if all previous groups were able
2651 static void add_event_to_ctx(struct perf_event *event,
2652 struct perf_event_context *ctx)
2654 list_add_event(event, ctx);
2655 perf_group_attach(event);
2658 static void task_ctx_sched_out(struct perf_event_context *ctx,
2659 enum event_type_t event_type)
2661 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2663 if (!cpuctx->task_ctx)
2666 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2669 ctx_sched_out(ctx, event_type);
2672 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2673 struct perf_event_context *ctx)
2675 ctx_sched_in(&cpuctx->ctx, EVENT_PINNED);
2677 ctx_sched_in(ctx, EVENT_PINNED);
2678 ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE);
2680 ctx_sched_in(ctx, EVENT_FLEXIBLE);
2684 * We want to maintain the following priority of scheduling:
2685 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2686 * - task pinned (EVENT_PINNED)
2687 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2688 * - task flexible (EVENT_FLEXIBLE).
2690 * In order to avoid unscheduling and scheduling back in everything every
2691 * time an event is added, only do it for the groups of equal priority and
2694 * This can be called after a batch operation on task events, in which case
2695 * event_type is a bit mask of the types of events involved. For CPU events,
2696 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2699 * XXX: ctx_resched() reschedule entire perf_event_context while adding new
2700 * event to the context or enabling existing event in the context. We can
2701 * probably optimize it by rescheduling only affected pmu_ctx.
2703 static void ctx_resched(struct perf_cpu_context *cpuctx,
2704 struct perf_event_context *task_ctx,
2705 enum event_type_t event_type)
2707 bool cpu_event = !!(event_type & EVENT_CPU);
2710 * If pinned groups are involved, flexible groups also need to be
2713 if (event_type & EVENT_PINNED)
2714 event_type |= EVENT_FLEXIBLE;
2716 event_type &= EVENT_ALL;
2718 perf_ctx_disable(&cpuctx->ctx, false);
2720 perf_ctx_disable(task_ctx, false);
2721 task_ctx_sched_out(task_ctx, event_type);
2725 * Decide which cpu ctx groups to schedule out based on the types
2726 * of events that caused rescheduling:
2727 * - EVENT_CPU: schedule out corresponding groups;
2728 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2729 * - otherwise, do nothing more.
2732 ctx_sched_out(&cpuctx->ctx, event_type);
2733 else if (event_type & EVENT_PINNED)
2734 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
2736 perf_event_sched_in(cpuctx, task_ctx);
2738 perf_ctx_enable(&cpuctx->ctx, false);
2740 perf_ctx_enable(task_ctx, false);
2743 void perf_pmu_resched(struct pmu *pmu)
2745 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2746 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2748 perf_ctx_lock(cpuctx, task_ctx);
2749 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2750 perf_ctx_unlock(cpuctx, task_ctx);
2754 * Cross CPU call to install and enable a performance event
2756 * Very similar to remote_function() + event_function() but cannot assume that
2757 * things like ctx->is_active and cpuctx->task_ctx are set.
2759 static int __perf_install_in_context(void *info)
2761 struct perf_event *event = info;
2762 struct perf_event_context *ctx = event->ctx;
2763 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2764 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2765 bool reprogram = true;
2768 raw_spin_lock(&cpuctx->ctx.lock);
2770 raw_spin_lock(&ctx->lock);
2773 reprogram = (ctx->task == current);
2776 * If the task is running, it must be running on this CPU,
2777 * otherwise we cannot reprogram things.
2779 * If its not running, we don't care, ctx->lock will
2780 * serialize against it becoming runnable.
2782 if (task_curr(ctx->task) && !reprogram) {
2787 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2788 } else if (task_ctx) {
2789 raw_spin_lock(&task_ctx->lock);
2792 #ifdef CONFIG_CGROUP_PERF
2793 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2795 * If the current cgroup doesn't match the event's
2796 * cgroup, we should not try to schedule it.
2798 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2799 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2800 event->cgrp->css.cgroup);
2805 ctx_sched_out(ctx, EVENT_TIME);
2806 add_event_to_ctx(event, ctx);
2807 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2809 add_event_to_ctx(event, ctx);
2813 perf_ctx_unlock(cpuctx, task_ctx);
2818 static bool exclusive_event_installable(struct perf_event *event,
2819 struct perf_event_context *ctx);
2822 * Attach a performance event to a context.
2824 * Very similar to event_function_call, see comment there.
2827 perf_install_in_context(struct perf_event_context *ctx,
2828 struct perf_event *event,
2831 struct task_struct *task = READ_ONCE(ctx->task);
2833 lockdep_assert_held(&ctx->mutex);
2835 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2837 if (event->cpu != -1)
2838 WARN_ON_ONCE(event->cpu != cpu);
2841 * Ensures that if we can observe event->ctx, both the event and ctx
2842 * will be 'complete'. See perf_iterate_sb_cpu().
2844 smp_store_release(&event->ctx, ctx);
2847 * perf_event_attr::disabled events will not run and can be initialized
2848 * without IPI. Except when this is the first event for the context, in
2849 * that case we need the magic of the IPI to set ctx->is_active.
2851 * The IOC_ENABLE that is sure to follow the creation of a disabled
2852 * event will issue the IPI and reprogram the hardware.
2854 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2855 ctx->nr_events && !is_cgroup_event(event)) {
2856 raw_spin_lock_irq(&ctx->lock);
2857 if (ctx->task == TASK_TOMBSTONE) {
2858 raw_spin_unlock_irq(&ctx->lock);
2861 add_event_to_ctx(event, ctx);
2862 raw_spin_unlock_irq(&ctx->lock);
2867 cpu_function_call(cpu, __perf_install_in_context, event);
2872 * Should not happen, we validate the ctx is still alive before calling.
2874 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2878 * Installing events is tricky because we cannot rely on ctx->is_active
2879 * to be set in case this is the nr_events 0 -> 1 transition.
2881 * Instead we use task_curr(), which tells us if the task is running.
2882 * However, since we use task_curr() outside of rq::lock, we can race
2883 * against the actual state. This means the result can be wrong.
2885 * If we get a false positive, we retry, this is harmless.
2887 * If we get a false negative, things are complicated. If we are after
2888 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2889 * value must be correct. If we're before, it doesn't matter since
2890 * perf_event_context_sched_in() will program the counter.
2892 * However, this hinges on the remote context switch having observed
2893 * our task->perf_event_ctxp[] store, such that it will in fact take
2894 * ctx::lock in perf_event_context_sched_in().
2896 * We do this by task_function_call(), if the IPI fails to hit the task
2897 * we know any future context switch of task must see the
2898 * perf_event_ctpx[] store.
2902 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2903 * task_cpu() load, such that if the IPI then does not find the task
2904 * running, a future context switch of that task must observe the
2909 if (!task_function_call(task, __perf_install_in_context, event))
2912 raw_spin_lock_irq(&ctx->lock);
2914 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2916 * Cannot happen because we already checked above (which also
2917 * cannot happen), and we hold ctx->mutex, which serializes us
2918 * against perf_event_exit_task_context().
2920 raw_spin_unlock_irq(&ctx->lock);
2924 * If the task is not running, ctx->lock will avoid it becoming so,
2925 * thus we can safely install the event.
2927 if (task_curr(task)) {
2928 raw_spin_unlock_irq(&ctx->lock);
2931 add_event_to_ctx(event, ctx);
2932 raw_spin_unlock_irq(&ctx->lock);
2936 * Cross CPU call to enable a performance event
2938 static void __perf_event_enable(struct perf_event *event,
2939 struct perf_cpu_context *cpuctx,
2940 struct perf_event_context *ctx,
2943 struct perf_event *leader = event->group_leader;
2944 struct perf_event_context *task_ctx;
2946 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2947 event->state <= PERF_EVENT_STATE_ERROR)
2951 ctx_sched_out(ctx, EVENT_TIME);
2953 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2954 perf_cgroup_event_enable(event, ctx);
2956 if (!ctx->is_active)
2959 if (!event_filter_match(event)) {
2960 ctx_sched_in(ctx, EVENT_TIME);
2965 * If the event is in a group and isn't the group leader,
2966 * then don't put it on unless the group is on.
2968 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2969 ctx_sched_in(ctx, EVENT_TIME);
2973 task_ctx = cpuctx->task_ctx;
2975 WARN_ON_ONCE(task_ctx != ctx);
2977 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2983 * If event->ctx is a cloned context, callers must make sure that
2984 * every task struct that event->ctx->task could possibly point to
2985 * remains valid. This condition is satisfied when called through
2986 * perf_event_for_each_child or perf_event_for_each as described
2987 * for perf_event_disable.
2989 static void _perf_event_enable(struct perf_event *event)
2991 struct perf_event_context *ctx = event->ctx;
2993 raw_spin_lock_irq(&ctx->lock);
2994 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2995 event->state < PERF_EVENT_STATE_ERROR) {
2997 raw_spin_unlock_irq(&ctx->lock);
3002 * If the event is in error state, clear that first.
3004 * That way, if we see the event in error state below, we know that it
3005 * has gone back into error state, as distinct from the task having
3006 * been scheduled away before the cross-call arrived.
3008 if (event->state == PERF_EVENT_STATE_ERROR) {
3010 * Detached SIBLING events cannot leave ERROR state.
3012 if (event->event_caps & PERF_EV_CAP_SIBLING &&
3013 event->group_leader == event)
3016 event->state = PERF_EVENT_STATE_OFF;
3018 raw_spin_unlock_irq(&ctx->lock);
3020 event_function_call(event, __perf_event_enable, NULL);
3024 * See perf_event_disable();
3026 void perf_event_enable(struct perf_event *event)
3028 struct perf_event_context *ctx;
3030 ctx = perf_event_ctx_lock(event);
3031 _perf_event_enable(event);
3032 perf_event_ctx_unlock(event, ctx);
3034 EXPORT_SYMBOL_GPL(perf_event_enable);
3036 struct stop_event_data {
3037 struct perf_event *event;
3038 unsigned int restart;
3041 static int __perf_event_stop(void *info)
3043 struct stop_event_data *sd = info;
3044 struct perf_event *event = sd->event;
3046 /* if it's already INACTIVE, do nothing */
3047 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3050 /* matches smp_wmb() in event_sched_in() */
3054 * There is a window with interrupts enabled before we get here,
3055 * so we need to check again lest we try to stop another CPU's event.
3057 if (READ_ONCE(event->oncpu) != smp_processor_id())
3060 event->pmu->stop(event, PERF_EF_UPDATE);
3063 * May race with the actual stop (through perf_pmu_output_stop()),
3064 * but it is only used for events with AUX ring buffer, and such
3065 * events will refuse to restart because of rb::aux_mmap_count==0,
3066 * see comments in perf_aux_output_begin().
3068 * Since this is happening on an event-local CPU, no trace is lost
3072 event->pmu->start(event, 0);
3077 static int perf_event_stop(struct perf_event *event, int restart)
3079 struct stop_event_data sd = {
3086 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3089 /* matches smp_wmb() in event_sched_in() */
3093 * We only want to restart ACTIVE events, so if the event goes
3094 * inactive here (event->oncpu==-1), there's nothing more to do;
3095 * fall through with ret==-ENXIO.
3097 ret = cpu_function_call(READ_ONCE(event->oncpu),
3098 __perf_event_stop, &sd);
3099 } while (ret == -EAGAIN);
3105 * In order to contain the amount of racy and tricky in the address filter
3106 * configuration management, it is a two part process:
3108 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3109 * we update the addresses of corresponding vmas in
3110 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3111 * (p2) when an event is scheduled in (pmu::add), it calls
3112 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3113 * if the generation has changed since the previous call.
3115 * If (p1) happens while the event is active, we restart it to force (p2).
3117 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3118 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3120 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3121 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3123 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3126 void perf_event_addr_filters_sync(struct perf_event *event)
3128 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3130 if (!has_addr_filter(event))
3133 raw_spin_lock(&ifh->lock);
3134 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3135 event->pmu->addr_filters_sync(event);
3136 event->hw.addr_filters_gen = event->addr_filters_gen;
3138 raw_spin_unlock(&ifh->lock);
3140 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3142 static int _perf_event_refresh(struct perf_event *event, int refresh)
3145 * not supported on inherited events
3147 if (event->attr.inherit || !is_sampling_event(event))
3150 atomic_add(refresh, &event->event_limit);
3151 _perf_event_enable(event);
3157 * See perf_event_disable()
3159 int perf_event_refresh(struct perf_event *event, int refresh)
3161 struct perf_event_context *ctx;
3164 ctx = perf_event_ctx_lock(event);
3165 ret = _perf_event_refresh(event, refresh);
3166 perf_event_ctx_unlock(event, ctx);
3170 EXPORT_SYMBOL_GPL(perf_event_refresh);
3172 static int perf_event_modify_breakpoint(struct perf_event *bp,
3173 struct perf_event_attr *attr)
3177 _perf_event_disable(bp);
3179 err = modify_user_hw_breakpoint_check(bp, attr, true);
3181 if (!bp->attr.disabled)
3182 _perf_event_enable(bp);
3188 * Copy event-type-independent attributes that may be modified.
3190 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3191 const struct perf_event_attr *from)
3193 to->sig_data = from->sig_data;
3196 static int perf_event_modify_attr(struct perf_event *event,
3197 struct perf_event_attr *attr)
3199 int (*func)(struct perf_event *, struct perf_event_attr *);
3200 struct perf_event *child;
3203 if (event->attr.type != attr->type)
3206 switch (event->attr.type) {
3207 case PERF_TYPE_BREAKPOINT:
3208 func = perf_event_modify_breakpoint;
3211 /* Place holder for future additions. */
3215 WARN_ON_ONCE(event->ctx->parent_ctx);
3217 mutex_lock(&event->child_mutex);
3219 * Event-type-independent attributes must be copied before event-type
3220 * modification, which will validate that final attributes match the
3221 * source attributes after all relevant attributes have been copied.
3223 perf_event_modify_copy_attr(&event->attr, attr);
3224 err = func(event, attr);
3227 list_for_each_entry(child, &event->child_list, child_list) {
3228 perf_event_modify_copy_attr(&child->attr, attr);
3229 err = func(child, attr);
3234 mutex_unlock(&event->child_mutex);
3238 static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx,
3239 enum event_type_t event_type)
3241 struct perf_event_context *ctx = pmu_ctx->ctx;
3242 struct perf_event *event, *tmp;
3243 struct pmu *pmu = pmu_ctx->pmu;
3245 if (ctx->task && !ctx->is_active) {
3246 struct perf_cpu_pmu_context *cpc;
3248 cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3249 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3250 cpc->task_epc = NULL;
3256 perf_pmu_disable(pmu);
3257 if (event_type & EVENT_PINNED) {
3258 list_for_each_entry_safe(event, tmp,
3259 &pmu_ctx->pinned_active,
3261 group_sched_out(event, ctx);
3264 if (event_type & EVENT_FLEXIBLE) {
3265 list_for_each_entry_safe(event, tmp,
3266 &pmu_ctx->flexible_active,
3268 group_sched_out(event, ctx);
3270 * Since we cleared EVENT_FLEXIBLE, also clear
3271 * rotate_necessary, is will be reset by
3272 * ctx_flexible_sched_in() when needed.
3274 pmu_ctx->rotate_necessary = 0;
3276 perf_pmu_enable(pmu);
3280 ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type)
3282 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3283 struct perf_event_pmu_context *pmu_ctx;
3284 int is_active = ctx->is_active;
3285 bool cgroup = event_type & EVENT_CGROUP;
3287 event_type &= ~EVENT_CGROUP;
3289 lockdep_assert_held(&ctx->lock);
3291 if (likely(!ctx->nr_events)) {
3293 * See __perf_remove_from_context().
3295 WARN_ON_ONCE(ctx->is_active);
3297 WARN_ON_ONCE(cpuctx->task_ctx);
3302 * Always update time if it was set; not only when it changes.
3303 * Otherwise we can 'forget' to update time for any but the last
3304 * context we sched out. For example:
3306 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3307 * ctx_sched_out(.event_type = EVENT_PINNED)
3309 * would only update time for the pinned events.
3311 if (is_active & EVENT_TIME) {
3312 /* update (and stop) ctx time */
3313 update_context_time(ctx);
3314 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3316 * CPU-release for the below ->is_active store,
3317 * see __load_acquire() in perf_event_time_now()
3322 ctx->is_active &= ~event_type;
3323 if (!(ctx->is_active & EVENT_ALL))
3327 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3328 if (!ctx->is_active)
3329 cpuctx->task_ctx = NULL;
3332 is_active ^= ctx->is_active; /* changed bits */
3334 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3335 if (cgroup && !pmu_ctx->nr_cgroups)
3337 __pmu_ctx_sched_out(pmu_ctx, is_active);
3342 * Test whether two contexts are equivalent, i.e. whether they have both been
3343 * cloned from the same version of the same context.
3345 * Equivalence is measured using a generation number in the context that is
3346 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3347 * and list_del_event().
3349 static int context_equiv(struct perf_event_context *ctx1,
3350 struct perf_event_context *ctx2)
3352 lockdep_assert_held(&ctx1->lock);
3353 lockdep_assert_held(&ctx2->lock);
3355 /* Pinning disables the swap optimization */
3356 if (ctx1->pin_count || ctx2->pin_count)
3359 /* If ctx1 is the parent of ctx2 */
3360 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3363 /* If ctx2 is the parent of ctx1 */
3364 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3368 * If ctx1 and ctx2 have the same parent; we flatten the parent
3369 * hierarchy, see perf_event_init_context().
3371 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3372 ctx1->parent_gen == ctx2->parent_gen)
3379 static void __perf_event_sync_stat(struct perf_event *event,
3380 struct perf_event *next_event)
3384 if (!event->attr.inherit_stat)
3388 * Update the event value, we cannot use perf_event_read()
3389 * because we're in the middle of a context switch and have IRQs
3390 * disabled, which upsets smp_call_function_single(), however
3391 * we know the event must be on the current CPU, therefore we
3392 * don't need to use it.
3394 if (event->state == PERF_EVENT_STATE_ACTIVE)
3395 event->pmu->read(event);
3397 perf_event_update_time(event);
3400 * In order to keep per-task stats reliable we need to flip the event
3401 * values when we flip the contexts.
3403 value = local64_read(&next_event->count);
3404 value = local64_xchg(&event->count, value);
3405 local64_set(&next_event->count, value);
3407 swap(event->total_time_enabled, next_event->total_time_enabled);
3408 swap(event->total_time_running, next_event->total_time_running);
3411 * Since we swizzled the values, update the user visible data too.
3413 perf_event_update_userpage(event);
3414 perf_event_update_userpage(next_event);
3417 static void perf_event_sync_stat(struct perf_event_context *ctx,
3418 struct perf_event_context *next_ctx)
3420 struct perf_event *event, *next_event;
3425 update_context_time(ctx);
3427 event = list_first_entry(&ctx->event_list,
3428 struct perf_event, event_entry);
3430 next_event = list_first_entry(&next_ctx->event_list,
3431 struct perf_event, event_entry);
3433 while (&event->event_entry != &ctx->event_list &&
3434 &next_event->event_entry != &next_ctx->event_list) {
3436 __perf_event_sync_stat(event, next_event);
3438 event = list_next_entry(event, event_entry);
3439 next_event = list_next_entry(next_event, event_entry);
3443 #define double_list_for_each_entry(pos1, pos2, head1, head2, member) \
3444 for (pos1 = list_first_entry(head1, typeof(*pos1), member), \
3445 pos2 = list_first_entry(head2, typeof(*pos2), member); \
3446 !list_entry_is_head(pos1, head1, member) && \
3447 !list_entry_is_head(pos2, head2, member); \
3448 pos1 = list_next_entry(pos1, member), \
3449 pos2 = list_next_entry(pos2, member))
3451 static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx,
3452 struct perf_event_context *next_ctx)
3454 struct perf_event_pmu_context *prev_epc, *next_epc;
3456 if (!prev_ctx->nr_task_data)
3459 double_list_for_each_entry(prev_epc, next_epc,
3460 &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list,
3463 if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu))
3467 * PMU specific parts of task perf context can require
3468 * additional synchronization. As an example of such
3469 * synchronization see implementation details of Intel
3470 * LBR call stack data profiling;
3472 if (prev_epc->pmu->swap_task_ctx)
3473 prev_epc->pmu->swap_task_ctx(prev_epc, next_epc);
3475 swap(prev_epc->task_ctx_data, next_epc->task_ctx_data);
3479 static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in)
3481 struct perf_event_pmu_context *pmu_ctx;
3482 struct perf_cpu_pmu_context *cpc;
3484 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3485 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3487 if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task)
3488 pmu_ctx->pmu->sched_task(pmu_ctx, sched_in);
3493 perf_event_context_sched_out(struct task_struct *task, struct task_struct *next)
3495 struct perf_event_context *ctx = task->perf_event_ctxp;
3496 struct perf_event_context *next_ctx;
3497 struct perf_event_context *parent, *next_parent;
3504 next_ctx = rcu_dereference(next->perf_event_ctxp);
3508 parent = rcu_dereference(ctx->parent_ctx);
3509 next_parent = rcu_dereference(next_ctx->parent_ctx);
3511 /* If neither context have a parent context; they cannot be clones. */
3512 if (!parent && !next_parent)
3515 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3517 * Looks like the two contexts are clones, so we might be
3518 * able to optimize the context switch. We lock both
3519 * contexts and check that they are clones under the
3520 * lock (including re-checking that neither has been
3521 * uncloned in the meantime). It doesn't matter which
3522 * order we take the locks because no other cpu could
3523 * be trying to lock both of these tasks.
3525 raw_spin_lock(&ctx->lock);
3526 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3527 if (context_equiv(ctx, next_ctx)) {
3529 perf_ctx_disable(ctx, false);
3531 /* PMIs are disabled; ctx->nr_pending is stable. */
3532 if (local_read(&ctx->nr_pending) ||
3533 local_read(&next_ctx->nr_pending)) {
3535 * Must not swap out ctx when there's pending
3536 * events that rely on the ctx->task relation.
3538 raw_spin_unlock(&next_ctx->lock);
3543 WRITE_ONCE(ctx->task, next);
3544 WRITE_ONCE(next_ctx->task, task);
3546 perf_ctx_sched_task_cb(ctx, false);
3547 perf_event_swap_task_ctx_data(ctx, next_ctx);
3549 perf_ctx_enable(ctx, false);
3552 * RCU_INIT_POINTER here is safe because we've not
3553 * modified the ctx and the above modification of
3554 * ctx->task and ctx->task_ctx_data are immaterial
3555 * since those values are always verified under
3556 * ctx->lock which we're now holding.
3558 RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx);
3559 RCU_INIT_POINTER(next->perf_event_ctxp, ctx);
3563 perf_event_sync_stat(ctx, next_ctx);
3565 raw_spin_unlock(&next_ctx->lock);
3566 raw_spin_unlock(&ctx->lock);
3572 raw_spin_lock(&ctx->lock);
3573 perf_ctx_disable(ctx, false);
3576 perf_ctx_sched_task_cb(ctx, false);
3577 task_ctx_sched_out(ctx, EVENT_ALL);
3579 perf_ctx_enable(ctx, false);
3580 raw_spin_unlock(&ctx->lock);
3584 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3585 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
3587 void perf_sched_cb_dec(struct pmu *pmu)
3589 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3591 this_cpu_dec(perf_sched_cb_usages);
3594 if (!--cpc->sched_cb_usage)
3595 list_del(&cpc->sched_cb_entry);
3599 void perf_sched_cb_inc(struct pmu *pmu)
3601 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3603 if (!cpc->sched_cb_usage++)
3604 list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3607 this_cpu_inc(perf_sched_cb_usages);
3611 * This function provides the context switch callback to the lower code
3612 * layer. It is invoked ONLY when the context switch callback is enabled.
3614 * This callback is relevant even to per-cpu events; for example multi event
3615 * PEBS requires this to provide PID/TID information. This requires we flush
3616 * all queued PEBS records before we context switch to a new task.
3618 static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in)
3620 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3625 /* software PMUs will not have sched_task */
3626 if (WARN_ON_ONCE(!pmu->sched_task))
3629 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3630 perf_pmu_disable(pmu);
3632 pmu->sched_task(cpc->task_epc, sched_in);
3634 perf_pmu_enable(pmu);
3635 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3638 static void perf_pmu_sched_task(struct task_struct *prev,
3639 struct task_struct *next,
3642 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3643 struct perf_cpu_pmu_context *cpc;
3645 /* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */
3646 if (prev == next || cpuctx->task_ctx)
3649 list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry)
3650 __perf_pmu_sched_task(cpc, sched_in);
3653 static void perf_event_switch(struct task_struct *task,
3654 struct task_struct *next_prev, bool sched_in);
3657 * Called from scheduler to remove the events of the current task,
3658 * with interrupts disabled.
3660 * We stop each event and update the event value in event->count.
3662 * This does not protect us against NMI, but disable()
3663 * sets the disabled bit in the control field of event _before_
3664 * accessing the event control register. If a NMI hits, then it will
3665 * not restart the event.
3667 void __perf_event_task_sched_out(struct task_struct *task,
3668 struct task_struct *next)
3670 if (__this_cpu_read(perf_sched_cb_usages))
3671 perf_pmu_sched_task(task, next, false);
3673 if (atomic_read(&nr_switch_events))
3674 perf_event_switch(task, next, false);
3676 perf_event_context_sched_out(task, next);
3679 * if cgroup events exist on this CPU, then we need
3680 * to check if we have to switch out PMU state.
3681 * cgroup event are system-wide mode only
3683 perf_cgroup_switch(next);
3686 static bool perf_less_group_idx(const void *l, const void *r)
3688 const struct perf_event *le = *(const struct perf_event **)l;
3689 const struct perf_event *re = *(const struct perf_event **)r;
3691 return le->group_index < re->group_index;
3694 static void swap_ptr(void *l, void *r)
3696 void **lp = l, **rp = r;
3701 static const struct min_heap_callbacks perf_min_heap = {
3702 .elem_size = sizeof(struct perf_event *),
3703 .less = perf_less_group_idx,
3707 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3709 struct perf_event **itrs = heap->data;
3712 itrs[heap->nr] = event;
3717 static void __link_epc(struct perf_event_pmu_context *pmu_ctx)
3719 struct perf_cpu_pmu_context *cpc;
3721 if (!pmu_ctx->ctx->task)
3724 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3725 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3726 cpc->task_epc = pmu_ctx;
3729 static noinline int visit_groups_merge(struct perf_event_context *ctx,
3730 struct perf_event_groups *groups, int cpu,
3732 int (*func)(struct perf_event *, void *),
3735 #ifdef CONFIG_CGROUP_PERF
3736 struct cgroup_subsys_state *css = NULL;
3738 struct perf_cpu_context *cpuctx = NULL;
3739 /* Space for per CPU and/or any CPU event iterators. */
3740 struct perf_event *itrs[2];
3741 struct min_heap event_heap;
3742 struct perf_event **evt;
3745 if (pmu->filter && pmu->filter(pmu, cpu))
3749 cpuctx = this_cpu_ptr(&perf_cpu_context);
3750 event_heap = (struct min_heap){
3751 .data = cpuctx->heap,
3753 .size = cpuctx->heap_size,
3756 lockdep_assert_held(&cpuctx->ctx.lock);
3758 #ifdef CONFIG_CGROUP_PERF
3760 css = &cpuctx->cgrp->css;
3763 event_heap = (struct min_heap){
3766 .size = ARRAY_SIZE(itrs),
3768 /* Events not within a CPU context may be on any CPU. */
3769 __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL));
3771 evt = event_heap.data;
3773 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL));
3775 #ifdef CONFIG_CGROUP_PERF
3776 for (; css; css = css->parent)
3777 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup));
3780 if (event_heap.nr) {
3781 __link_epc((*evt)->pmu_ctx);
3782 perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu);
3785 min_heapify_all(&event_heap, &perf_min_heap);
3787 while (event_heap.nr) {
3788 ret = func(*evt, data);
3792 *evt = perf_event_groups_next(*evt, pmu);
3794 min_heapify(&event_heap, 0, &perf_min_heap);
3796 min_heap_pop(&event_heap, &perf_min_heap);
3803 * Because the userpage is strictly per-event (there is no concept of context,
3804 * so there cannot be a context indirection), every userpage must be updated
3805 * when context time starts :-(
3807 * IOW, we must not miss EVENT_TIME edges.
3809 static inline bool event_update_userpage(struct perf_event *event)
3811 if (likely(!atomic_read(&event->mmap_count)))
3814 perf_event_update_time(event);
3815 perf_event_update_userpage(event);
3820 static inline void group_update_userpage(struct perf_event *group_event)
3822 struct perf_event *event;
3824 if (!event_update_userpage(group_event))
3827 for_each_sibling_event(event, group_event)
3828 event_update_userpage(event);
3831 static int merge_sched_in(struct perf_event *event, void *data)
3833 struct perf_event_context *ctx = event->ctx;
3834 int *can_add_hw = data;
3836 if (event->state <= PERF_EVENT_STATE_OFF)
3839 if (!event_filter_match(event))
3842 if (group_can_go_on(event, *can_add_hw)) {
3843 if (!group_sched_in(event, ctx))
3844 list_add_tail(&event->active_list, get_event_list(event));
3847 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3849 if (event->attr.pinned) {
3850 perf_cgroup_event_disable(event, ctx);
3851 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3853 struct perf_cpu_pmu_context *cpc;
3855 event->pmu_ctx->rotate_necessary = 1;
3856 cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context);
3857 perf_mux_hrtimer_restart(cpc);
3858 group_update_userpage(event);
3865 static void pmu_groups_sched_in(struct perf_event_context *ctx,
3866 struct perf_event_groups *groups,
3870 visit_groups_merge(ctx, groups, smp_processor_id(), pmu,
3871 merge_sched_in, &can_add_hw);
3874 static void ctx_groups_sched_in(struct perf_event_context *ctx,
3875 struct perf_event_groups *groups,
3878 struct perf_event_pmu_context *pmu_ctx;
3880 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3881 if (cgroup && !pmu_ctx->nr_cgroups)
3883 pmu_groups_sched_in(ctx, groups, pmu_ctx->pmu);
3887 static void __pmu_ctx_sched_in(struct perf_event_context *ctx,
3890 pmu_groups_sched_in(ctx, &ctx->flexible_groups, pmu);
3894 ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type)
3896 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3897 int is_active = ctx->is_active;
3898 bool cgroup = event_type & EVENT_CGROUP;
3900 event_type &= ~EVENT_CGROUP;
3902 lockdep_assert_held(&ctx->lock);
3904 if (likely(!ctx->nr_events))
3907 if (!(is_active & EVENT_TIME)) {
3908 /* start ctx time */
3909 __update_context_time(ctx, false);
3910 perf_cgroup_set_timestamp(cpuctx);
3912 * CPU-release for the below ->is_active store,
3913 * see __load_acquire() in perf_event_time_now()
3918 ctx->is_active |= (event_type | EVENT_TIME);
3921 cpuctx->task_ctx = ctx;
3923 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3926 is_active ^= ctx->is_active; /* changed bits */
3929 * First go through the list and put on any pinned groups
3930 * in order to give them the best chance of going on.
3932 if (is_active & EVENT_PINNED)
3933 ctx_groups_sched_in(ctx, &ctx->pinned_groups, cgroup);
3935 /* Then walk through the lower prio flexible groups */
3936 if (is_active & EVENT_FLEXIBLE)
3937 ctx_groups_sched_in(ctx, &ctx->flexible_groups, cgroup);
3940 static void perf_event_context_sched_in(struct task_struct *task)
3942 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3943 struct perf_event_context *ctx;
3946 ctx = rcu_dereference(task->perf_event_ctxp);
3950 if (cpuctx->task_ctx == ctx) {
3951 perf_ctx_lock(cpuctx, ctx);
3952 perf_ctx_disable(ctx, false);
3954 perf_ctx_sched_task_cb(ctx, true);
3956 perf_ctx_enable(ctx, false);
3957 perf_ctx_unlock(cpuctx, ctx);
3961 perf_ctx_lock(cpuctx, ctx);
3963 * We must check ctx->nr_events while holding ctx->lock, such
3964 * that we serialize against perf_install_in_context().
3966 if (!ctx->nr_events)
3969 perf_ctx_disable(ctx, false);
3971 * We want to keep the following priority order:
3972 * cpu pinned (that don't need to move), task pinned,
3973 * cpu flexible, task flexible.
3975 * However, if task's ctx is not carrying any pinned
3976 * events, no need to flip the cpuctx's events around.
3978 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) {
3979 perf_ctx_disable(&cpuctx->ctx, false);
3980 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
3983 perf_event_sched_in(cpuctx, ctx);
3985 perf_ctx_sched_task_cb(cpuctx->task_ctx, true);
3987 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3988 perf_ctx_enable(&cpuctx->ctx, false);
3990 perf_ctx_enable(ctx, false);
3993 perf_ctx_unlock(cpuctx, ctx);
3999 * Called from scheduler to add the events of the current task
4000 * with interrupts disabled.
4002 * We restore the event value and then enable it.
4004 * This does not protect us against NMI, but enable()
4005 * sets the enabled bit in the control field of event _before_
4006 * accessing the event control register. If a NMI hits, then it will
4007 * keep the event running.
4009 void __perf_event_task_sched_in(struct task_struct *prev,
4010 struct task_struct *task)
4012 perf_event_context_sched_in(task);
4014 if (atomic_read(&nr_switch_events))
4015 perf_event_switch(task, prev, true);
4017 if (__this_cpu_read(perf_sched_cb_usages))
4018 perf_pmu_sched_task(prev, task, true);
4021 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
4023 u64 frequency = event->attr.sample_freq;
4024 u64 sec = NSEC_PER_SEC;
4025 u64 divisor, dividend;
4027 int count_fls, nsec_fls, frequency_fls, sec_fls;
4029 count_fls = fls64(count);
4030 nsec_fls = fls64(nsec);
4031 frequency_fls = fls64(frequency);
4035 * We got @count in @nsec, with a target of sample_freq HZ
4036 * the target period becomes:
4039 * period = -------------------
4040 * @nsec * sample_freq
4045 * Reduce accuracy by one bit such that @a and @b converge
4046 * to a similar magnitude.
4048 #define REDUCE_FLS(a, b) \
4050 if (a##_fls > b##_fls) { \
4060 * Reduce accuracy until either term fits in a u64, then proceed with
4061 * the other, so that finally we can do a u64/u64 division.
4063 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4064 REDUCE_FLS(nsec, frequency);
4065 REDUCE_FLS(sec, count);
4068 if (count_fls + sec_fls > 64) {
4069 divisor = nsec * frequency;
4071 while (count_fls + sec_fls > 64) {
4072 REDUCE_FLS(count, sec);
4076 dividend = count * sec;
4078 dividend = count * sec;
4080 while (nsec_fls + frequency_fls > 64) {
4081 REDUCE_FLS(nsec, frequency);
4085 divisor = nsec * frequency;
4091 return div64_u64(dividend, divisor);
4094 static DEFINE_PER_CPU(int, perf_throttled_count);
4095 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4097 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4099 struct hw_perf_event *hwc = &event->hw;
4100 s64 period, sample_period;
4103 period = perf_calculate_period(event, nsec, count);
4105 delta = (s64)(period - hwc->sample_period);
4106 delta = (delta + 7) / 8; /* low pass filter */
4108 sample_period = hwc->sample_period + delta;
4113 hwc->sample_period = sample_period;
4115 if (local64_read(&hwc->period_left) > 8*sample_period) {
4117 event->pmu->stop(event, PERF_EF_UPDATE);
4119 local64_set(&hwc->period_left, 0);
4122 event->pmu->start(event, PERF_EF_RELOAD);
4127 * combine freq adjustment with unthrottling to avoid two passes over the
4128 * events. At the same time, make sure, having freq events does not change
4129 * the rate of unthrottling as that would introduce bias.
4132 perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle)
4134 struct perf_event *event;
4135 struct hw_perf_event *hwc;
4136 u64 now, period = TICK_NSEC;
4140 * only need to iterate over all events iff:
4141 * - context have events in frequency mode (needs freq adjust)
4142 * - there are events to unthrottle on this cpu
4144 if (!(ctx->nr_freq || unthrottle))
4147 raw_spin_lock(&ctx->lock);
4149 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4150 if (event->state != PERF_EVENT_STATE_ACTIVE)
4153 // XXX use visit thingy to avoid the -1,cpu match
4154 if (!event_filter_match(event))
4157 perf_pmu_disable(event->pmu);
4161 if (hwc->interrupts == MAX_INTERRUPTS) {
4162 hwc->interrupts = 0;
4163 perf_log_throttle(event, 1);
4164 event->pmu->start(event, 0);
4167 if (!event->attr.freq || !event->attr.sample_freq)
4171 * stop the event and update event->count
4173 event->pmu->stop(event, PERF_EF_UPDATE);
4175 now = local64_read(&event->count);
4176 delta = now - hwc->freq_count_stamp;
4177 hwc->freq_count_stamp = now;
4181 * reload only if value has changed
4182 * we have stopped the event so tell that
4183 * to perf_adjust_period() to avoid stopping it
4187 perf_adjust_period(event, period, delta, false);
4189 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4191 perf_pmu_enable(event->pmu);
4194 raw_spin_unlock(&ctx->lock);
4198 * Move @event to the tail of the @ctx's elegible events.
4200 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4203 * Rotate the first entry last of non-pinned groups. Rotation might be
4204 * disabled by the inheritance code.
4206 if (ctx->rotate_disable)
4209 perf_event_groups_delete(&ctx->flexible_groups, event);
4210 perf_event_groups_insert(&ctx->flexible_groups, event);
4213 /* pick an event from the flexible_groups to rotate */
4214 static inline struct perf_event *
4215 ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx)
4217 struct perf_event *event;
4218 struct rb_node *node;
4219 struct rb_root *tree;
4220 struct __group_key key = {
4221 .pmu = pmu_ctx->pmu,
4224 /* pick the first active flexible event */
4225 event = list_first_entry_or_null(&pmu_ctx->flexible_active,
4226 struct perf_event, active_list);
4230 /* if no active flexible event, pick the first event */
4231 tree = &pmu_ctx->ctx->flexible_groups.tree;
4233 if (!pmu_ctx->ctx->task) {
4234 key.cpu = smp_processor_id();
4236 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4238 event = __node_2_pe(node);
4243 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4245 event = __node_2_pe(node);
4249 key.cpu = smp_processor_id();
4250 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4252 event = __node_2_pe(node);
4256 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4257 * finds there are unschedulable events, it will set it again.
4259 pmu_ctx->rotate_necessary = 0;
4264 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc)
4266 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4267 struct perf_event_pmu_context *cpu_epc, *task_epc = NULL;
4268 struct perf_event *cpu_event = NULL, *task_event = NULL;
4269 int cpu_rotate, task_rotate;
4273 * Since we run this from IRQ context, nobody can install new
4274 * events, thus the event count values are stable.
4277 cpu_epc = &cpc->epc;
4279 task_epc = cpc->task_epc;
4281 cpu_rotate = cpu_epc->rotate_necessary;
4282 task_rotate = task_epc ? task_epc->rotate_necessary : 0;
4284 if (!(cpu_rotate || task_rotate))
4287 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4288 perf_pmu_disable(pmu);
4291 task_event = ctx_event_to_rotate(task_epc);
4293 cpu_event = ctx_event_to_rotate(cpu_epc);
4296 * As per the order given at ctx_resched() first 'pop' task flexible
4297 * and then, if needed CPU flexible.
4299 if (task_event || (task_epc && cpu_event)) {
4300 update_context_time(task_epc->ctx);
4301 __pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE);
4305 update_context_time(&cpuctx->ctx);
4306 __pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE);
4307 rotate_ctx(&cpuctx->ctx, cpu_event);
4308 __pmu_ctx_sched_in(&cpuctx->ctx, pmu);
4312 rotate_ctx(task_epc->ctx, task_event);
4314 if (task_event || (task_epc && cpu_event))
4315 __pmu_ctx_sched_in(task_epc->ctx, pmu);
4317 perf_pmu_enable(pmu);
4318 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4323 void perf_event_task_tick(void)
4325 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4326 struct perf_event_context *ctx;
4329 lockdep_assert_irqs_disabled();
4331 __this_cpu_inc(perf_throttled_seq);
4332 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4333 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4335 perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled);
4338 ctx = rcu_dereference(current->perf_event_ctxp);
4340 perf_adjust_freq_unthr_context(ctx, !!throttled);
4344 static int event_enable_on_exec(struct perf_event *event,
4345 struct perf_event_context *ctx)
4347 if (!event->attr.enable_on_exec)
4350 event->attr.enable_on_exec = 0;
4351 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4354 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4360 * Enable all of a task's events that have been marked enable-on-exec.
4361 * This expects task == current.
4363 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
4365 struct perf_event_context *clone_ctx = NULL;
4366 enum event_type_t event_type = 0;
4367 struct perf_cpu_context *cpuctx;
4368 struct perf_event *event;
4369 unsigned long flags;
4372 local_irq_save(flags);
4373 if (WARN_ON_ONCE(current->perf_event_ctxp != ctx))
4376 if (!ctx->nr_events)
4379 cpuctx = this_cpu_ptr(&perf_cpu_context);
4380 perf_ctx_lock(cpuctx, ctx);
4381 ctx_sched_out(ctx, EVENT_TIME);
4383 list_for_each_entry(event, &ctx->event_list, event_entry) {
4384 enabled |= event_enable_on_exec(event, ctx);
4385 event_type |= get_event_type(event);
4389 * Unclone and reschedule this context if we enabled any event.
4392 clone_ctx = unclone_ctx(ctx);
4393 ctx_resched(cpuctx, ctx, event_type);
4395 ctx_sched_in(ctx, EVENT_TIME);
4397 perf_ctx_unlock(cpuctx, ctx);
4400 local_irq_restore(flags);
4406 static void perf_remove_from_owner(struct perf_event *event);
4407 static void perf_event_exit_event(struct perf_event *event,
4408 struct perf_event_context *ctx);
4411 * Removes all events from the current task that have been marked
4412 * remove-on-exec, and feeds their values back to parent events.
4414 static void perf_event_remove_on_exec(struct perf_event_context *ctx)
4416 struct perf_event_context *clone_ctx = NULL;
4417 struct perf_event *event, *next;
4418 unsigned long flags;
4419 bool modified = false;
4421 mutex_lock(&ctx->mutex);
4423 if (WARN_ON_ONCE(ctx->task != current))
4426 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4427 if (!event->attr.remove_on_exec)
4430 if (!is_kernel_event(event))
4431 perf_remove_from_owner(event);
4435 perf_event_exit_event(event, ctx);
4438 raw_spin_lock_irqsave(&ctx->lock, flags);
4440 clone_ctx = unclone_ctx(ctx);
4441 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4444 mutex_unlock(&ctx->mutex);
4450 struct perf_read_data {
4451 struct perf_event *event;
4456 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4458 u16 local_pkg, event_pkg;
4460 if ((unsigned)event_cpu >= nr_cpu_ids)
4463 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4464 int local_cpu = smp_processor_id();
4466 event_pkg = topology_physical_package_id(event_cpu);
4467 local_pkg = topology_physical_package_id(local_cpu);
4469 if (event_pkg == local_pkg)
4477 * Cross CPU call to read the hardware event
4479 static void __perf_event_read(void *info)
4481 struct perf_read_data *data = info;
4482 struct perf_event *sub, *event = data->event;
4483 struct perf_event_context *ctx = event->ctx;
4484 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4485 struct pmu *pmu = event->pmu;
4488 * If this is a task context, we need to check whether it is
4489 * the current task context of this cpu. If not it has been
4490 * scheduled out before the smp call arrived. In that case
4491 * event->count would have been updated to a recent sample
4492 * when the event was scheduled out.
4494 if (ctx->task && cpuctx->task_ctx != ctx)
4497 raw_spin_lock(&ctx->lock);
4498 if (ctx->is_active & EVENT_TIME) {
4499 update_context_time(ctx);
4500 update_cgrp_time_from_event(event);
4503 perf_event_update_time(event);
4505 perf_event_update_sibling_time(event);
4507 if (event->state != PERF_EVENT_STATE_ACTIVE)
4516 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4520 for_each_sibling_event(sub, event) {
4521 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4523 * Use sibling's PMU rather than @event's since
4524 * sibling could be on different (eg: software) PMU.
4526 sub->pmu->read(sub);
4530 data->ret = pmu->commit_txn(pmu);
4533 raw_spin_unlock(&ctx->lock);
4536 static inline u64 perf_event_count(struct perf_event *event)
4538 return local64_read(&event->count) + atomic64_read(&event->child_count);
4541 static void calc_timer_values(struct perf_event *event,
4548 *now = perf_clock();
4549 ctx_time = perf_event_time_now(event, *now);
4550 __perf_update_times(event, ctx_time, enabled, running);
4554 * NMI-safe method to read a local event, that is an event that
4556 * - either for the current task, or for this CPU
4557 * - does not have inherit set, for inherited task events
4558 * will not be local and we cannot read them atomically
4559 * - must not have a pmu::count method
4561 int perf_event_read_local(struct perf_event *event, u64 *value,
4562 u64 *enabled, u64 *running)
4564 unsigned long flags;
4570 * Disabling interrupts avoids all counter scheduling (context
4571 * switches, timer based rotation and IPIs).
4573 local_irq_save(flags);
4576 * It must not be an event with inherit set, we cannot read
4577 * all child counters from atomic context.
4579 if (event->attr.inherit) {
4584 /* If this is a per-task event, it must be for current */
4585 if ((event->attach_state & PERF_ATTACH_TASK) &&
4586 event->hw.target != current) {
4592 * Get the event CPU numbers, and adjust them to local if the event is
4593 * a per-package event that can be read locally
4595 event_oncpu = __perf_event_read_cpu(event, event->oncpu);
4596 event_cpu = __perf_event_read_cpu(event, event->cpu);
4598 /* If this is a per-CPU event, it must be for this CPU */
4599 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4600 event_cpu != smp_processor_id()) {
4605 /* If this is a pinned event it must be running on this CPU */
4606 if (event->attr.pinned && event_oncpu != smp_processor_id()) {
4612 * If the event is currently on this CPU, its either a per-task event,
4613 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4616 if (event_oncpu == smp_processor_id())
4617 event->pmu->read(event);
4619 *value = local64_read(&event->count);
4620 if (enabled || running) {
4621 u64 __enabled, __running, __now;
4623 calc_timer_values(event, &__now, &__enabled, &__running);
4625 *enabled = __enabled;
4627 *running = __running;
4630 local_irq_restore(flags);
4635 static int perf_event_read(struct perf_event *event, bool group)
4637 enum perf_event_state state = READ_ONCE(event->state);
4638 int event_cpu, ret = 0;
4641 * If event is enabled and currently active on a CPU, update the
4642 * value in the event structure:
4645 if (state == PERF_EVENT_STATE_ACTIVE) {
4646 struct perf_read_data data;
4649 * Orders the ->state and ->oncpu loads such that if we see
4650 * ACTIVE we must also see the right ->oncpu.
4652 * Matches the smp_wmb() from event_sched_in().
4656 event_cpu = READ_ONCE(event->oncpu);
4657 if ((unsigned)event_cpu >= nr_cpu_ids)
4660 data = (struct perf_read_data){
4667 event_cpu = __perf_event_read_cpu(event, event_cpu);
4670 * Purposely ignore the smp_call_function_single() return
4673 * If event_cpu isn't a valid CPU it means the event got
4674 * scheduled out and that will have updated the event count.
4676 * Therefore, either way, we'll have an up-to-date event count
4679 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4683 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4684 struct perf_event_context *ctx = event->ctx;
4685 unsigned long flags;
4687 raw_spin_lock_irqsave(&ctx->lock, flags);
4688 state = event->state;
4689 if (state != PERF_EVENT_STATE_INACTIVE) {
4690 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4695 * May read while context is not active (e.g., thread is
4696 * blocked), in that case we cannot update context time
4698 if (ctx->is_active & EVENT_TIME) {
4699 update_context_time(ctx);
4700 update_cgrp_time_from_event(event);
4703 perf_event_update_time(event);
4705 perf_event_update_sibling_time(event);
4706 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4713 * Initialize the perf_event context in a task_struct:
4715 static void __perf_event_init_context(struct perf_event_context *ctx)
4717 raw_spin_lock_init(&ctx->lock);
4718 mutex_init(&ctx->mutex);
4719 INIT_LIST_HEAD(&ctx->pmu_ctx_list);
4720 perf_event_groups_init(&ctx->pinned_groups);
4721 perf_event_groups_init(&ctx->flexible_groups);
4722 INIT_LIST_HEAD(&ctx->event_list);
4723 refcount_set(&ctx->refcount, 1);
4727 __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu)
4730 INIT_LIST_HEAD(&epc->pmu_ctx_entry);
4731 INIT_LIST_HEAD(&epc->pinned_active);
4732 INIT_LIST_HEAD(&epc->flexible_active);
4733 atomic_set(&epc->refcount, 1);
4736 static struct perf_event_context *
4737 alloc_perf_context(struct task_struct *task)
4739 struct perf_event_context *ctx;
4741 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4745 __perf_event_init_context(ctx);
4747 ctx->task = get_task_struct(task);
4752 static struct task_struct *
4753 find_lively_task_by_vpid(pid_t vpid)
4755 struct task_struct *task;
4761 task = find_task_by_vpid(vpid);
4763 get_task_struct(task);
4767 return ERR_PTR(-ESRCH);
4773 * Returns a matching context with refcount and pincount.
4775 static struct perf_event_context *
4776 find_get_context(struct task_struct *task, struct perf_event *event)
4778 struct perf_event_context *ctx, *clone_ctx = NULL;
4779 struct perf_cpu_context *cpuctx;
4780 unsigned long flags;
4784 /* Must be root to operate on a CPU event: */
4785 err = perf_allow_cpu(&event->attr);
4787 return ERR_PTR(err);
4789 cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
4792 raw_spin_lock_irqsave(&ctx->lock, flags);
4794 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4801 ctx = perf_lock_task_context(task, &flags);
4803 clone_ctx = unclone_ctx(ctx);
4806 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4811 ctx = alloc_perf_context(task);
4817 mutex_lock(&task->perf_event_mutex);
4819 * If it has already passed perf_event_exit_task().
4820 * we must see PF_EXITING, it takes this mutex too.
4822 if (task->flags & PF_EXITING)
4824 else if (task->perf_event_ctxp)
4829 rcu_assign_pointer(task->perf_event_ctxp, ctx);
4831 mutex_unlock(&task->perf_event_mutex);
4833 if (unlikely(err)) {
4845 return ERR_PTR(err);
4848 static struct perf_event_pmu_context *
4849 find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx,
4850 struct perf_event *event)
4852 struct perf_event_pmu_context *new = NULL, *epc;
4853 void *task_ctx_data = NULL;
4857 * perf_pmu_migrate_context() / __perf_pmu_install_event()
4858 * relies on the fact that find_get_pmu_context() cannot fail
4861 struct perf_cpu_pmu_context *cpc;
4863 cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu);
4865 raw_spin_lock_irq(&ctx->lock);
4867 atomic_set(&epc->refcount, 1);
4869 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4872 WARN_ON_ONCE(epc->ctx != ctx);
4873 atomic_inc(&epc->refcount);
4875 raw_spin_unlock_irq(&ctx->lock);
4879 new = kzalloc(sizeof(*epc), GFP_KERNEL);
4881 return ERR_PTR(-ENOMEM);
4883 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4884 task_ctx_data = alloc_task_ctx_data(pmu);
4885 if (!task_ctx_data) {
4887 return ERR_PTR(-ENOMEM);
4891 __perf_init_event_pmu_context(new, pmu);
4896 * lockdep_assert_held(&ctx->mutex);
4898 * can't because perf_event_init_task() doesn't actually hold the
4902 raw_spin_lock_irq(&ctx->lock);
4903 list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) {
4904 if (epc->pmu == pmu) {
4905 WARN_ON_ONCE(epc->ctx != ctx);
4906 atomic_inc(&epc->refcount);
4914 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4918 if (task_ctx_data && !epc->task_ctx_data) {
4919 epc->task_ctx_data = task_ctx_data;
4920 task_ctx_data = NULL;
4921 ctx->nr_task_data++;
4923 raw_spin_unlock_irq(&ctx->lock);
4925 free_task_ctx_data(pmu, task_ctx_data);
4931 static void get_pmu_ctx(struct perf_event_pmu_context *epc)
4933 WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount));
4936 static void free_epc_rcu(struct rcu_head *head)
4938 struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head);
4940 kfree(epc->task_ctx_data);
4944 static void put_pmu_ctx(struct perf_event_pmu_context *epc)
4946 struct perf_event_context *ctx = epc->ctx;
4947 unsigned long flags;
4952 * lockdep_assert_held(&ctx->mutex);
4954 * can't because of the call-site in _free_event()/put_event()
4955 * which isn't always called under ctx->mutex.
4957 if (!atomic_dec_and_raw_lock_irqsave(&epc->refcount, &ctx->lock, flags))
4960 WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry));
4962 list_del_init(&epc->pmu_ctx_entry);
4965 WARN_ON_ONCE(!list_empty(&epc->pinned_active));
4966 WARN_ON_ONCE(!list_empty(&epc->flexible_active));
4968 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4973 call_rcu(&epc->rcu_head, free_epc_rcu);
4976 static void perf_event_free_filter(struct perf_event *event);
4978 static void free_event_rcu(struct rcu_head *head)
4980 struct perf_event *event = container_of(head, typeof(*event), rcu_head);
4983 put_pid_ns(event->ns);
4984 perf_event_free_filter(event);
4985 kmem_cache_free(perf_event_cache, event);
4988 static void ring_buffer_attach(struct perf_event *event,
4989 struct perf_buffer *rb);
4991 static void detach_sb_event(struct perf_event *event)
4993 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4995 raw_spin_lock(&pel->lock);
4996 list_del_rcu(&event->sb_list);
4997 raw_spin_unlock(&pel->lock);
5000 static bool is_sb_event(struct perf_event *event)
5002 struct perf_event_attr *attr = &event->attr;
5007 if (event->attach_state & PERF_ATTACH_TASK)
5010 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
5011 attr->comm || attr->comm_exec ||
5012 attr->task || attr->ksymbol ||
5013 attr->context_switch || attr->text_poke ||
5019 static void unaccount_pmu_sb_event(struct perf_event *event)
5021 if (is_sb_event(event))
5022 detach_sb_event(event);
5025 #ifdef CONFIG_NO_HZ_FULL
5026 static DEFINE_SPINLOCK(nr_freq_lock);
5029 static void unaccount_freq_event_nohz(void)
5031 #ifdef CONFIG_NO_HZ_FULL
5032 spin_lock(&nr_freq_lock);
5033 if (atomic_dec_and_test(&nr_freq_events))
5034 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
5035 spin_unlock(&nr_freq_lock);
5039 static void unaccount_freq_event(void)
5041 if (tick_nohz_full_enabled())
5042 unaccount_freq_event_nohz();
5044 atomic_dec(&nr_freq_events);
5047 static void unaccount_event(struct perf_event *event)
5054 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
5056 if (event->attr.mmap || event->attr.mmap_data)
5057 atomic_dec(&nr_mmap_events);
5058 if (event->attr.build_id)
5059 atomic_dec(&nr_build_id_events);
5060 if (event->attr.comm)
5061 atomic_dec(&nr_comm_events);
5062 if (event->attr.namespaces)
5063 atomic_dec(&nr_namespaces_events);
5064 if (event->attr.cgroup)
5065 atomic_dec(&nr_cgroup_events);
5066 if (event->attr.task)
5067 atomic_dec(&nr_task_events);
5068 if (event->attr.freq)
5069 unaccount_freq_event();
5070 if (event->attr.context_switch) {
5072 atomic_dec(&nr_switch_events);
5074 if (is_cgroup_event(event))
5076 if (has_branch_stack(event))
5078 if (event->attr.ksymbol)
5079 atomic_dec(&nr_ksymbol_events);
5080 if (event->attr.bpf_event)
5081 atomic_dec(&nr_bpf_events);
5082 if (event->attr.text_poke)
5083 atomic_dec(&nr_text_poke_events);
5086 if (!atomic_add_unless(&perf_sched_count, -1, 1))
5087 schedule_delayed_work(&perf_sched_work, HZ);
5090 unaccount_pmu_sb_event(event);
5093 static void perf_sched_delayed(struct work_struct *work)
5095 mutex_lock(&perf_sched_mutex);
5096 if (atomic_dec_and_test(&perf_sched_count))
5097 static_branch_disable(&perf_sched_events);
5098 mutex_unlock(&perf_sched_mutex);
5102 * The following implement mutual exclusion of events on "exclusive" pmus
5103 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
5104 * at a time, so we disallow creating events that might conflict, namely:
5106 * 1) cpu-wide events in the presence of per-task events,
5107 * 2) per-task events in the presence of cpu-wide events,
5108 * 3) two matching events on the same perf_event_context.
5110 * The former two cases are handled in the allocation path (perf_event_alloc(),
5111 * _free_event()), the latter -- before the first perf_install_in_context().
5113 static int exclusive_event_init(struct perf_event *event)
5115 struct pmu *pmu = event->pmu;
5117 if (!is_exclusive_pmu(pmu))
5121 * Prevent co-existence of per-task and cpu-wide events on the
5122 * same exclusive pmu.
5124 * Negative pmu::exclusive_cnt means there are cpu-wide
5125 * events on this "exclusive" pmu, positive means there are
5128 * Since this is called in perf_event_alloc() path, event::ctx
5129 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
5130 * to mean "per-task event", because unlike other attach states it
5131 * never gets cleared.
5133 if (event->attach_state & PERF_ATTACH_TASK) {
5134 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
5137 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
5144 static void exclusive_event_destroy(struct perf_event *event)
5146 struct pmu *pmu = event->pmu;
5148 if (!is_exclusive_pmu(pmu))
5151 /* see comment in exclusive_event_init() */
5152 if (event->attach_state & PERF_ATTACH_TASK)
5153 atomic_dec(&pmu->exclusive_cnt);
5155 atomic_inc(&pmu->exclusive_cnt);
5158 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
5160 if ((e1->pmu == e2->pmu) &&
5161 (e1->cpu == e2->cpu ||
5168 static bool exclusive_event_installable(struct perf_event *event,
5169 struct perf_event_context *ctx)
5171 struct perf_event *iter_event;
5172 struct pmu *pmu = event->pmu;
5174 lockdep_assert_held(&ctx->mutex);
5176 if (!is_exclusive_pmu(pmu))
5179 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5180 if (exclusive_event_match(iter_event, event))
5187 static void perf_addr_filters_splice(struct perf_event *event,
5188 struct list_head *head);
5190 static void _free_event(struct perf_event *event)
5192 irq_work_sync(&event->pending_irq);
5194 unaccount_event(event);
5196 security_perf_event_free(event);
5200 * Can happen when we close an event with re-directed output.
5202 * Since we have a 0 refcount, perf_mmap_close() will skip
5203 * over us; possibly making our ring_buffer_put() the last.
5205 mutex_lock(&event->mmap_mutex);
5206 ring_buffer_attach(event, NULL);
5207 mutex_unlock(&event->mmap_mutex);
5210 if (is_cgroup_event(event))
5211 perf_detach_cgroup(event);
5213 if (!event->parent) {
5214 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5215 put_callchain_buffers();
5218 perf_event_free_bpf_prog(event);
5219 perf_addr_filters_splice(event, NULL);
5220 kfree(event->addr_filter_ranges);
5223 event->destroy(event);
5226 * Must be after ->destroy(), due to uprobe_perf_close() using
5229 if (event->hw.target)
5230 put_task_struct(event->hw.target);
5233 put_pmu_ctx(event->pmu_ctx);
5236 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5237 * all task references must be cleaned up.
5240 put_ctx(event->ctx);
5242 exclusive_event_destroy(event);
5243 module_put(event->pmu->module);
5245 call_rcu(&event->rcu_head, free_event_rcu);
5249 * Used to free events which have a known refcount of 1, such as in error paths
5250 * where the event isn't exposed yet and inherited events.
5252 static void free_event(struct perf_event *event)
5254 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5255 "unexpected event refcount: %ld; ptr=%p\n",
5256 atomic_long_read(&event->refcount), event)) {
5257 /* leak to avoid use-after-free */
5265 * Remove user event from the owner task.
5267 static void perf_remove_from_owner(struct perf_event *event)
5269 struct task_struct *owner;
5273 * Matches the smp_store_release() in perf_event_exit_task(). If we
5274 * observe !owner it means the list deletion is complete and we can
5275 * indeed free this event, otherwise we need to serialize on
5276 * owner->perf_event_mutex.
5278 owner = READ_ONCE(event->owner);
5281 * Since delayed_put_task_struct() also drops the last
5282 * task reference we can safely take a new reference
5283 * while holding the rcu_read_lock().
5285 get_task_struct(owner);
5291 * If we're here through perf_event_exit_task() we're already
5292 * holding ctx->mutex which would be an inversion wrt. the
5293 * normal lock order.
5295 * However we can safely take this lock because its the child
5298 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5301 * We have to re-check the event->owner field, if it is cleared
5302 * we raced with perf_event_exit_task(), acquiring the mutex
5303 * ensured they're done, and we can proceed with freeing the
5307 list_del_init(&event->owner_entry);
5308 smp_store_release(&event->owner, NULL);
5310 mutex_unlock(&owner->perf_event_mutex);
5311 put_task_struct(owner);
5315 static void put_event(struct perf_event *event)
5317 if (!atomic_long_dec_and_test(&event->refcount))
5324 * Kill an event dead; while event:refcount will preserve the event
5325 * object, it will not preserve its functionality. Once the last 'user'
5326 * gives up the object, we'll destroy the thing.
5328 int perf_event_release_kernel(struct perf_event *event)
5330 struct perf_event_context *ctx = event->ctx;
5331 struct perf_event *child, *tmp;
5332 LIST_HEAD(free_list);
5335 * If we got here through err_alloc: free_event(event); we will not
5336 * have attached to a context yet.
5339 WARN_ON_ONCE(event->attach_state &
5340 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5344 if (!is_kernel_event(event))
5345 perf_remove_from_owner(event);
5347 ctx = perf_event_ctx_lock(event);
5348 WARN_ON_ONCE(ctx->parent_ctx);
5351 * Mark this event as STATE_DEAD, there is no external reference to it
5354 * Anybody acquiring event->child_mutex after the below loop _must_
5355 * also see this, most importantly inherit_event() which will avoid
5356 * placing more children on the list.
5358 * Thus this guarantees that we will in fact observe and kill _ALL_
5361 perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD);
5363 perf_event_ctx_unlock(event, ctx);
5366 mutex_lock(&event->child_mutex);
5367 list_for_each_entry(child, &event->child_list, child_list) {
5370 * Cannot change, child events are not migrated, see the
5371 * comment with perf_event_ctx_lock_nested().
5373 ctx = READ_ONCE(child->ctx);
5375 * Since child_mutex nests inside ctx::mutex, we must jump
5376 * through hoops. We start by grabbing a reference on the ctx.
5378 * Since the event cannot get freed while we hold the
5379 * child_mutex, the context must also exist and have a !0
5385 * Now that we have a ctx ref, we can drop child_mutex, and
5386 * acquire ctx::mutex without fear of it going away. Then we
5387 * can re-acquire child_mutex.
5389 mutex_unlock(&event->child_mutex);
5390 mutex_lock(&ctx->mutex);
5391 mutex_lock(&event->child_mutex);
5394 * Now that we hold ctx::mutex and child_mutex, revalidate our
5395 * state, if child is still the first entry, it didn't get freed
5396 * and we can continue doing so.
5398 tmp = list_first_entry_or_null(&event->child_list,
5399 struct perf_event, child_list);
5401 perf_remove_from_context(child, DETACH_GROUP);
5402 list_move(&child->child_list, &free_list);
5404 * This matches the refcount bump in inherit_event();
5405 * this can't be the last reference.
5410 mutex_unlock(&event->child_mutex);
5411 mutex_unlock(&ctx->mutex);
5415 mutex_unlock(&event->child_mutex);
5417 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5418 void *var = &child->ctx->refcount;
5420 list_del(&child->child_list);
5424 * Wake any perf_event_free_task() waiting for this event to be
5427 smp_mb(); /* pairs with wait_var_event() */
5432 put_event(event); /* Must be the 'last' reference */
5435 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5438 * Called when the last reference to the file is gone.
5440 static int perf_release(struct inode *inode, struct file *file)
5442 perf_event_release_kernel(file->private_data);
5446 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5448 struct perf_event *child;
5454 mutex_lock(&event->child_mutex);
5456 (void)perf_event_read(event, false);
5457 total += perf_event_count(event);
5459 *enabled += event->total_time_enabled +
5460 atomic64_read(&event->child_total_time_enabled);
5461 *running += event->total_time_running +
5462 atomic64_read(&event->child_total_time_running);
5464 list_for_each_entry(child, &event->child_list, child_list) {
5465 (void)perf_event_read(child, false);
5466 total += perf_event_count(child);
5467 *enabled += child->total_time_enabled;
5468 *running += child->total_time_running;
5470 mutex_unlock(&event->child_mutex);
5475 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5477 struct perf_event_context *ctx;
5480 ctx = perf_event_ctx_lock(event);
5481 count = __perf_event_read_value(event, enabled, running);
5482 perf_event_ctx_unlock(event, ctx);
5486 EXPORT_SYMBOL_GPL(perf_event_read_value);
5488 static int __perf_read_group_add(struct perf_event *leader,
5489 u64 read_format, u64 *values)
5491 struct perf_event_context *ctx = leader->ctx;
5492 struct perf_event *sub, *parent;
5493 unsigned long flags;
5494 int n = 1; /* skip @nr */
5497 ret = perf_event_read(leader, true);
5501 raw_spin_lock_irqsave(&ctx->lock, flags);
5503 * Verify the grouping between the parent and child (inherited)
5504 * events is still in tact.
5507 * - leader->ctx->lock pins leader->sibling_list
5508 * - parent->child_mutex pins parent->child_list
5509 * - parent->ctx->mutex pins parent->sibling_list
5511 * Because parent->ctx != leader->ctx (and child_list nests inside
5512 * ctx->mutex), group destruction is not atomic between children, also
5513 * see perf_event_release_kernel(). Additionally, parent can grow the
5516 * Therefore it is possible to have parent and child groups in a
5517 * different configuration and summing over such a beast makes no sense
5522 parent = leader->parent;
5524 (parent->group_generation != leader->group_generation ||
5525 parent->nr_siblings != leader->nr_siblings)) {
5531 * Since we co-schedule groups, {enabled,running} times of siblings
5532 * will be identical to those of the leader, so we only publish one
5535 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5536 values[n++] += leader->total_time_enabled +
5537 atomic64_read(&leader->child_total_time_enabled);
5540 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5541 values[n++] += leader->total_time_running +
5542 atomic64_read(&leader->child_total_time_running);
5546 * Write {count,id} tuples for every sibling.
5548 values[n++] += perf_event_count(leader);
5549 if (read_format & PERF_FORMAT_ID)
5550 values[n++] = primary_event_id(leader);
5551 if (read_format & PERF_FORMAT_LOST)
5552 values[n++] = atomic64_read(&leader->lost_samples);
5554 for_each_sibling_event(sub, leader) {
5555 values[n++] += perf_event_count(sub);
5556 if (read_format & PERF_FORMAT_ID)
5557 values[n++] = primary_event_id(sub);
5558 if (read_format & PERF_FORMAT_LOST)
5559 values[n++] = atomic64_read(&sub->lost_samples);
5563 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5567 static int perf_read_group(struct perf_event *event,
5568 u64 read_format, char __user *buf)
5570 struct perf_event *leader = event->group_leader, *child;
5571 struct perf_event_context *ctx = leader->ctx;
5575 lockdep_assert_held(&ctx->mutex);
5577 values = kzalloc(event->read_size, GFP_KERNEL);
5581 values[0] = 1 + leader->nr_siblings;
5583 mutex_lock(&leader->child_mutex);
5585 ret = __perf_read_group_add(leader, read_format, values);
5589 list_for_each_entry(child, &leader->child_list, child_list) {
5590 ret = __perf_read_group_add(child, read_format, values);
5595 mutex_unlock(&leader->child_mutex);
5597 ret = event->read_size;
5598 if (copy_to_user(buf, values, event->read_size))
5603 mutex_unlock(&leader->child_mutex);
5609 static int perf_read_one(struct perf_event *event,
5610 u64 read_format, char __user *buf)
5612 u64 enabled, running;
5616 values[n++] = __perf_event_read_value(event, &enabled, &running);
5617 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5618 values[n++] = enabled;
5619 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5620 values[n++] = running;
5621 if (read_format & PERF_FORMAT_ID)
5622 values[n++] = primary_event_id(event);
5623 if (read_format & PERF_FORMAT_LOST)
5624 values[n++] = atomic64_read(&event->lost_samples);
5626 if (copy_to_user(buf, values, n * sizeof(u64)))
5629 return n * sizeof(u64);
5632 static bool is_event_hup(struct perf_event *event)
5636 if (event->state > PERF_EVENT_STATE_EXIT)
5639 mutex_lock(&event->child_mutex);
5640 no_children = list_empty(&event->child_list);
5641 mutex_unlock(&event->child_mutex);
5646 * Read the performance event - simple non blocking version for now
5649 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5651 u64 read_format = event->attr.read_format;
5655 * Return end-of-file for a read on an event that is in
5656 * error state (i.e. because it was pinned but it couldn't be
5657 * scheduled on to the CPU at some point).
5659 if (event->state == PERF_EVENT_STATE_ERROR)
5662 if (count < event->read_size)
5665 WARN_ON_ONCE(event->ctx->parent_ctx);
5666 if (read_format & PERF_FORMAT_GROUP)
5667 ret = perf_read_group(event, read_format, buf);
5669 ret = perf_read_one(event, read_format, buf);
5675 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5677 struct perf_event *event = file->private_data;
5678 struct perf_event_context *ctx;
5681 ret = security_perf_event_read(event);
5685 ctx = perf_event_ctx_lock(event);
5686 ret = __perf_read(event, buf, count);
5687 perf_event_ctx_unlock(event, ctx);
5692 static __poll_t perf_poll(struct file *file, poll_table *wait)
5694 struct perf_event *event = file->private_data;
5695 struct perf_buffer *rb;
5696 __poll_t events = EPOLLHUP;
5698 poll_wait(file, &event->waitq, wait);
5700 if (is_event_hup(event))
5704 * Pin the event->rb by taking event->mmap_mutex; otherwise
5705 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5707 mutex_lock(&event->mmap_mutex);
5710 events = atomic_xchg(&rb->poll, 0);
5711 mutex_unlock(&event->mmap_mutex);
5715 static void _perf_event_reset(struct perf_event *event)
5717 (void)perf_event_read(event, false);
5718 local64_set(&event->count, 0);
5719 perf_event_update_userpage(event);
5722 /* Assume it's not an event with inherit set. */
5723 u64 perf_event_pause(struct perf_event *event, bool reset)
5725 struct perf_event_context *ctx;
5728 ctx = perf_event_ctx_lock(event);
5729 WARN_ON_ONCE(event->attr.inherit);
5730 _perf_event_disable(event);
5731 count = local64_read(&event->count);
5733 local64_set(&event->count, 0);
5734 perf_event_ctx_unlock(event, ctx);
5738 EXPORT_SYMBOL_GPL(perf_event_pause);
5741 * Holding the top-level event's child_mutex means that any
5742 * descendant process that has inherited this event will block
5743 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5744 * task existence requirements of perf_event_enable/disable.
5746 static void perf_event_for_each_child(struct perf_event *event,
5747 void (*func)(struct perf_event *))
5749 struct perf_event *child;
5751 WARN_ON_ONCE(event->ctx->parent_ctx);
5753 mutex_lock(&event->child_mutex);
5755 list_for_each_entry(child, &event->child_list, child_list)
5757 mutex_unlock(&event->child_mutex);
5760 static void perf_event_for_each(struct perf_event *event,
5761 void (*func)(struct perf_event *))
5763 struct perf_event_context *ctx = event->ctx;
5764 struct perf_event *sibling;
5766 lockdep_assert_held(&ctx->mutex);
5768 event = event->group_leader;
5770 perf_event_for_each_child(event, func);
5771 for_each_sibling_event(sibling, event)
5772 perf_event_for_each_child(sibling, func);
5775 static void __perf_event_period(struct perf_event *event,
5776 struct perf_cpu_context *cpuctx,
5777 struct perf_event_context *ctx,
5780 u64 value = *((u64 *)info);
5783 if (event->attr.freq) {
5784 event->attr.sample_freq = value;
5786 event->attr.sample_period = value;
5787 event->hw.sample_period = value;
5790 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5792 perf_pmu_disable(event->pmu);
5794 * We could be throttled; unthrottle now to avoid the tick
5795 * trying to unthrottle while we already re-started the event.
5797 if (event->hw.interrupts == MAX_INTERRUPTS) {
5798 event->hw.interrupts = 0;
5799 perf_log_throttle(event, 1);
5801 event->pmu->stop(event, PERF_EF_UPDATE);
5804 local64_set(&event->hw.period_left, 0);
5807 event->pmu->start(event, PERF_EF_RELOAD);
5808 perf_pmu_enable(event->pmu);
5812 static int perf_event_check_period(struct perf_event *event, u64 value)
5814 return event->pmu->check_period(event, value);
5817 static int _perf_event_period(struct perf_event *event, u64 value)
5819 if (!is_sampling_event(event))
5825 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5828 if (perf_event_check_period(event, value))
5831 if (!event->attr.freq && (value & (1ULL << 63)))
5834 event_function_call(event, __perf_event_period, &value);
5839 int perf_event_period(struct perf_event *event, u64 value)
5841 struct perf_event_context *ctx;
5844 ctx = perf_event_ctx_lock(event);
5845 ret = _perf_event_period(event, value);
5846 perf_event_ctx_unlock(event, ctx);
5850 EXPORT_SYMBOL_GPL(perf_event_period);
5852 static const struct file_operations perf_fops;
5854 static inline int perf_fget_light(int fd, struct fd *p)
5856 struct fd f = fdget(fd);
5860 if (f.file->f_op != &perf_fops) {
5868 static int perf_event_set_output(struct perf_event *event,
5869 struct perf_event *output_event);
5870 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5871 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5872 struct perf_event_attr *attr);
5874 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5876 void (*func)(struct perf_event *);
5880 case PERF_EVENT_IOC_ENABLE:
5881 func = _perf_event_enable;
5883 case PERF_EVENT_IOC_DISABLE:
5884 func = _perf_event_disable;
5886 case PERF_EVENT_IOC_RESET:
5887 func = _perf_event_reset;
5890 case PERF_EVENT_IOC_REFRESH:
5891 return _perf_event_refresh(event, arg);
5893 case PERF_EVENT_IOC_PERIOD:
5897 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5900 return _perf_event_period(event, value);
5902 case PERF_EVENT_IOC_ID:
5904 u64 id = primary_event_id(event);
5906 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5911 case PERF_EVENT_IOC_SET_OUTPUT:
5915 struct perf_event *output_event;
5917 ret = perf_fget_light(arg, &output);
5920 output_event = output.file->private_data;
5921 ret = perf_event_set_output(event, output_event);
5924 ret = perf_event_set_output(event, NULL);
5929 case PERF_EVENT_IOC_SET_FILTER:
5930 return perf_event_set_filter(event, (void __user *)arg);
5932 case PERF_EVENT_IOC_SET_BPF:
5934 struct bpf_prog *prog;
5937 prog = bpf_prog_get(arg);
5939 return PTR_ERR(prog);
5941 err = perf_event_set_bpf_prog(event, prog, 0);
5950 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5951 struct perf_buffer *rb;
5954 rb = rcu_dereference(event->rb);
5955 if (!rb || !rb->nr_pages) {
5959 rb_toggle_paused(rb, !!arg);
5964 case PERF_EVENT_IOC_QUERY_BPF:
5965 return perf_event_query_prog_array(event, (void __user *)arg);
5967 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5968 struct perf_event_attr new_attr;
5969 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5975 return perf_event_modify_attr(event, &new_attr);
5981 if (flags & PERF_IOC_FLAG_GROUP)
5982 perf_event_for_each(event, func);
5984 perf_event_for_each_child(event, func);
5989 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5991 struct perf_event *event = file->private_data;
5992 struct perf_event_context *ctx;
5995 /* Treat ioctl like writes as it is likely a mutating operation. */
5996 ret = security_perf_event_write(event);
6000 ctx = perf_event_ctx_lock(event);
6001 ret = _perf_ioctl(event, cmd, arg);
6002 perf_event_ctx_unlock(event, ctx);
6007 #ifdef CONFIG_COMPAT
6008 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
6011 switch (_IOC_NR(cmd)) {
6012 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
6013 case _IOC_NR(PERF_EVENT_IOC_ID):
6014 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
6015 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
6016 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
6017 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
6018 cmd &= ~IOCSIZE_MASK;
6019 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
6023 return perf_ioctl(file, cmd, arg);
6026 # define perf_compat_ioctl NULL
6029 int perf_event_task_enable(void)
6031 struct perf_event_context *ctx;
6032 struct perf_event *event;
6034 mutex_lock(¤t->perf_event_mutex);
6035 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
6036 ctx = perf_event_ctx_lock(event);
6037 perf_event_for_each_child(event, _perf_event_enable);
6038 perf_event_ctx_unlock(event, ctx);
6040 mutex_unlock(¤t->perf_event_mutex);
6045 int perf_event_task_disable(void)
6047 struct perf_event_context *ctx;
6048 struct perf_event *event;
6050 mutex_lock(¤t->perf_event_mutex);
6051 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
6052 ctx = perf_event_ctx_lock(event);
6053 perf_event_for_each_child(event, _perf_event_disable);
6054 perf_event_ctx_unlock(event, ctx);
6056 mutex_unlock(¤t->perf_event_mutex);
6061 static int perf_event_index(struct perf_event *event)
6063 if (event->hw.state & PERF_HES_STOPPED)
6066 if (event->state != PERF_EVENT_STATE_ACTIVE)
6069 return event->pmu->event_idx(event);
6072 static void perf_event_init_userpage(struct perf_event *event)
6074 struct perf_event_mmap_page *userpg;
6075 struct perf_buffer *rb;
6078 rb = rcu_dereference(event->rb);
6082 userpg = rb->user_page;
6084 /* Allow new userspace to detect that bit 0 is deprecated */
6085 userpg->cap_bit0_is_deprecated = 1;
6086 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
6087 userpg->data_offset = PAGE_SIZE;
6088 userpg->data_size = perf_data_size(rb);
6094 void __weak arch_perf_update_userpage(
6095 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
6100 * Callers need to ensure there can be no nesting of this function, otherwise
6101 * the seqlock logic goes bad. We can not serialize this because the arch
6102 * code calls this from NMI context.
6104 void perf_event_update_userpage(struct perf_event *event)
6106 struct perf_event_mmap_page *userpg;
6107 struct perf_buffer *rb;
6108 u64 enabled, running, now;
6111 rb = rcu_dereference(event->rb);
6116 * compute total_time_enabled, total_time_running
6117 * based on snapshot values taken when the event
6118 * was last scheduled in.
6120 * we cannot simply called update_context_time()
6121 * because of locking issue as we can be called in
6124 calc_timer_values(event, &now, &enabled, &running);
6126 userpg = rb->user_page;
6128 * Disable preemption to guarantee consistent time stamps are stored to
6134 userpg->index = perf_event_index(event);
6135 userpg->offset = perf_event_count(event);
6137 userpg->offset -= local64_read(&event->hw.prev_count);
6139 userpg->time_enabled = enabled +
6140 atomic64_read(&event->child_total_time_enabled);
6142 userpg->time_running = running +
6143 atomic64_read(&event->child_total_time_running);
6145 arch_perf_update_userpage(event, userpg, now);
6153 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
6155 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
6157 struct perf_event *event = vmf->vma->vm_file->private_data;
6158 struct perf_buffer *rb;
6159 vm_fault_t ret = VM_FAULT_SIGBUS;
6161 if (vmf->flags & FAULT_FLAG_MKWRITE) {
6162 if (vmf->pgoff == 0)
6168 rb = rcu_dereference(event->rb);
6172 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
6175 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
6179 get_page(vmf->page);
6180 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
6181 vmf->page->index = vmf->pgoff;
6190 static void ring_buffer_attach(struct perf_event *event,
6191 struct perf_buffer *rb)
6193 struct perf_buffer *old_rb = NULL;
6194 unsigned long flags;
6196 WARN_ON_ONCE(event->parent);
6200 * Should be impossible, we set this when removing
6201 * event->rb_entry and wait/clear when adding event->rb_entry.
6203 WARN_ON_ONCE(event->rcu_pending);
6206 spin_lock_irqsave(&old_rb->event_lock, flags);
6207 list_del_rcu(&event->rb_entry);
6208 spin_unlock_irqrestore(&old_rb->event_lock, flags);
6210 event->rcu_batches = get_state_synchronize_rcu();
6211 event->rcu_pending = 1;
6215 if (event->rcu_pending) {
6216 cond_synchronize_rcu(event->rcu_batches);
6217 event->rcu_pending = 0;
6220 spin_lock_irqsave(&rb->event_lock, flags);
6221 list_add_rcu(&event->rb_entry, &rb->event_list);
6222 spin_unlock_irqrestore(&rb->event_lock, flags);
6226 * Avoid racing with perf_mmap_close(AUX): stop the event
6227 * before swizzling the event::rb pointer; if it's getting
6228 * unmapped, its aux_mmap_count will be 0 and it won't
6229 * restart. See the comment in __perf_pmu_output_stop().
6231 * Data will inevitably be lost when set_output is done in
6232 * mid-air, but then again, whoever does it like this is
6233 * not in for the data anyway.
6236 perf_event_stop(event, 0);
6238 rcu_assign_pointer(event->rb, rb);
6241 ring_buffer_put(old_rb);
6243 * Since we detached before setting the new rb, so that we
6244 * could attach the new rb, we could have missed a wakeup.
6247 wake_up_all(&event->waitq);
6251 static void ring_buffer_wakeup(struct perf_event *event)
6253 struct perf_buffer *rb;
6256 event = event->parent;
6259 rb = rcu_dereference(event->rb);
6261 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6262 wake_up_all(&event->waitq);
6267 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6269 struct perf_buffer *rb;
6272 event = event->parent;
6275 rb = rcu_dereference(event->rb);
6277 if (!refcount_inc_not_zero(&rb->refcount))
6285 void ring_buffer_put(struct perf_buffer *rb)
6287 if (!refcount_dec_and_test(&rb->refcount))
6290 WARN_ON_ONCE(!list_empty(&rb->event_list));
6292 call_rcu(&rb->rcu_head, rb_free_rcu);
6295 static void perf_mmap_open(struct vm_area_struct *vma)
6297 struct perf_event *event = vma->vm_file->private_data;
6299 atomic_inc(&event->mmap_count);
6300 atomic_inc(&event->rb->mmap_count);
6303 atomic_inc(&event->rb->aux_mmap_count);
6305 if (event->pmu->event_mapped)
6306 event->pmu->event_mapped(event, vma->vm_mm);
6309 static void perf_pmu_output_stop(struct perf_event *event);
6312 * A buffer can be mmap()ed multiple times; either directly through the same
6313 * event, or through other events by use of perf_event_set_output().
6315 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6316 * the buffer here, where we still have a VM context. This means we need
6317 * to detach all events redirecting to us.
6319 static void perf_mmap_close(struct vm_area_struct *vma)
6321 struct perf_event *event = vma->vm_file->private_data;
6322 struct perf_buffer *rb = ring_buffer_get(event);
6323 struct user_struct *mmap_user = rb->mmap_user;
6324 int mmap_locked = rb->mmap_locked;
6325 unsigned long size = perf_data_size(rb);
6326 bool detach_rest = false;
6328 if (event->pmu->event_unmapped)
6329 event->pmu->event_unmapped(event, vma->vm_mm);
6332 * rb->aux_mmap_count will always drop before rb->mmap_count and
6333 * event->mmap_count, so it is ok to use event->mmap_mutex to
6334 * serialize with perf_mmap here.
6336 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6337 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6339 * Stop all AUX events that are writing to this buffer,
6340 * so that we can free its AUX pages and corresponding PMU
6341 * data. Note that after rb::aux_mmap_count dropped to zero,
6342 * they won't start any more (see perf_aux_output_begin()).
6344 perf_pmu_output_stop(event);
6346 /* now it's safe to free the pages */
6347 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6348 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6350 /* this has to be the last one */
6352 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6354 mutex_unlock(&event->mmap_mutex);
6357 if (atomic_dec_and_test(&rb->mmap_count))
6360 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6363 ring_buffer_attach(event, NULL);
6364 mutex_unlock(&event->mmap_mutex);
6366 /* If there's still other mmap()s of this buffer, we're done. */
6371 * No other mmap()s, detach from all other events that might redirect
6372 * into the now unreachable buffer. Somewhat complicated by the
6373 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6377 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6378 if (!atomic_long_inc_not_zero(&event->refcount)) {
6380 * This event is en-route to free_event() which will
6381 * detach it and remove it from the list.
6387 mutex_lock(&event->mmap_mutex);
6389 * Check we didn't race with perf_event_set_output() which can
6390 * swizzle the rb from under us while we were waiting to
6391 * acquire mmap_mutex.
6393 * If we find a different rb; ignore this event, a next
6394 * iteration will no longer find it on the list. We have to
6395 * still restart the iteration to make sure we're not now
6396 * iterating the wrong list.
6398 if (event->rb == rb)
6399 ring_buffer_attach(event, NULL);
6401 mutex_unlock(&event->mmap_mutex);
6405 * Restart the iteration; either we're on the wrong list or
6406 * destroyed its integrity by doing a deletion.
6413 * It could be there's still a few 0-ref events on the list; they'll
6414 * get cleaned up by free_event() -- they'll also still have their
6415 * ref on the rb and will free it whenever they are done with it.
6417 * Aside from that, this buffer is 'fully' detached and unmapped,
6418 * undo the VM accounting.
6421 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6422 &mmap_user->locked_vm);
6423 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6424 free_uid(mmap_user);
6427 ring_buffer_put(rb); /* could be last */
6430 static const struct vm_operations_struct perf_mmap_vmops = {
6431 .open = perf_mmap_open,
6432 .close = perf_mmap_close, /* non mergeable */
6433 .fault = perf_mmap_fault,
6434 .page_mkwrite = perf_mmap_fault,
6437 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6439 struct perf_event *event = file->private_data;
6440 unsigned long user_locked, user_lock_limit;
6441 struct user_struct *user = current_user();
6442 struct perf_buffer *rb = NULL;
6443 unsigned long locked, lock_limit;
6444 unsigned long vma_size;
6445 unsigned long nr_pages;
6446 long user_extra = 0, extra = 0;
6447 int ret = 0, flags = 0;
6450 * Don't allow mmap() of inherited per-task counters. This would
6451 * create a performance issue due to all children writing to the
6454 if (event->cpu == -1 && event->attr.inherit)
6457 if (!(vma->vm_flags & VM_SHARED))
6460 ret = security_perf_event_read(event);
6464 vma_size = vma->vm_end - vma->vm_start;
6466 if (vma->vm_pgoff == 0) {
6467 nr_pages = (vma_size / PAGE_SIZE) - 1;
6470 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6471 * mapped, all subsequent mappings should have the same size
6472 * and offset. Must be above the normal perf buffer.
6474 u64 aux_offset, aux_size;
6479 nr_pages = vma_size / PAGE_SIZE;
6481 mutex_lock(&event->mmap_mutex);
6488 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6489 aux_size = READ_ONCE(rb->user_page->aux_size);
6491 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6494 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6497 /* already mapped with a different offset */
6498 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6501 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6504 /* already mapped with a different size */
6505 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6508 if (!is_power_of_2(nr_pages))
6511 if (!atomic_inc_not_zero(&rb->mmap_count))
6514 if (rb_has_aux(rb)) {
6515 atomic_inc(&rb->aux_mmap_count);
6520 atomic_set(&rb->aux_mmap_count, 1);
6521 user_extra = nr_pages;
6527 * If we have rb pages ensure they're a power-of-two number, so we
6528 * can do bitmasks instead of modulo.
6530 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6533 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6536 WARN_ON_ONCE(event->ctx->parent_ctx);
6538 mutex_lock(&event->mmap_mutex);
6540 if (data_page_nr(event->rb) != nr_pages) {
6545 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6547 * Raced against perf_mmap_close(); remove the
6548 * event and try again.
6550 ring_buffer_attach(event, NULL);
6551 mutex_unlock(&event->mmap_mutex);
6558 user_extra = nr_pages + 1;
6561 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6564 * Increase the limit linearly with more CPUs:
6566 user_lock_limit *= num_online_cpus();
6568 user_locked = atomic_long_read(&user->locked_vm);
6571 * sysctl_perf_event_mlock may have changed, so that
6572 * user->locked_vm > user_lock_limit
6574 if (user_locked > user_lock_limit)
6575 user_locked = user_lock_limit;
6576 user_locked += user_extra;
6578 if (user_locked > user_lock_limit) {
6580 * charge locked_vm until it hits user_lock_limit;
6581 * charge the rest from pinned_vm
6583 extra = user_locked - user_lock_limit;
6584 user_extra -= extra;
6587 lock_limit = rlimit(RLIMIT_MEMLOCK);
6588 lock_limit >>= PAGE_SHIFT;
6589 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6591 if ((locked > lock_limit) && perf_is_paranoid() &&
6592 !capable(CAP_IPC_LOCK)) {
6597 WARN_ON(!rb && event->rb);
6599 if (vma->vm_flags & VM_WRITE)
6600 flags |= RING_BUFFER_WRITABLE;
6603 rb = rb_alloc(nr_pages,
6604 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6612 atomic_set(&rb->mmap_count, 1);
6613 rb->mmap_user = get_current_user();
6614 rb->mmap_locked = extra;
6616 ring_buffer_attach(event, rb);
6618 perf_event_update_time(event);
6619 perf_event_init_userpage(event);
6620 perf_event_update_userpage(event);
6622 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6623 event->attr.aux_watermark, flags);
6625 rb->aux_mmap_locked = extra;
6630 atomic_long_add(user_extra, &user->locked_vm);
6631 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6633 atomic_inc(&event->mmap_count);
6635 atomic_dec(&rb->mmap_count);
6638 mutex_unlock(&event->mmap_mutex);
6641 * Since pinned accounting is per vm we cannot allow fork() to copy our
6644 vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP);
6645 vma->vm_ops = &perf_mmap_vmops;
6647 if (event->pmu->event_mapped)
6648 event->pmu->event_mapped(event, vma->vm_mm);
6653 static int perf_fasync(int fd, struct file *filp, int on)
6655 struct inode *inode = file_inode(filp);
6656 struct perf_event *event = filp->private_data;
6660 retval = fasync_helper(fd, filp, on, &event->fasync);
6661 inode_unlock(inode);
6669 static const struct file_operations perf_fops = {
6670 .llseek = no_llseek,
6671 .release = perf_release,
6674 .unlocked_ioctl = perf_ioctl,
6675 .compat_ioctl = perf_compat_ioctl,
6677 .fasync = perf_fasync,
6683 * If there's data, ensure we set the poll() state and publish everything
6684 * to user-space before waking everybody up.
6687 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6689 /* only the parent has fasync state */
6691 event = event->parent;
6692 return &event->fasync;
6695 void perf_event_wakeup(struct perf_event *event)
6697 ring_buffer_wakeup(event);
6699 if (event->pending_kill) {
6700 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6701 event->pending_kill = 0;
6705 static void perf_sigtrap(struct perf_event *event)
6708 * We'd expect this to only occur if the irq_work is delayed and either
6709 * ctx->task or current has changed in the meantime. This can be the
6710 * case on architectures that do not implement arch_irq_work_raise().
6712 if (WARN_ON_ONCE(event->ctx->task != current))
6716 * Both perf_pending_task() and perf_pending_irq() can race with the
6719 if (current->flags & PF_EXITING)
6722 send_sig_perf((void __user *)event->pending_addr,
6723 event->orig_type, event->attr.sig_data);
6727 * Deliver the pending work in-event-context or follow the context.
6729 static void __perf_pending_irq(struct perf_event *event)
6731 int cpu = READ_ONCE(event->oncpu);
6734 * If the event isn't running; we done. event_sched_out() will have
6735 * taken care of things.
6741 * Yay, we hit home and are in the context of the event.
6743 if (cpu == smp_processor_id()) {
6744 if (event->pending_sigtrap) {
6745 event->pending_sigtrap = 0;
6746 perf_sigtrap(event);
6747 local_dec(&event->ctx->nr_pending);
6749 if (event->pending_disable) {
6750 event->pending_disable = 0;
6751 perf_event_disable_local(event);
6759 * perf_event_disable_inatomic()
6760 * @pending_disable = CPU-A;
6764 * @pending_disable = -1;
6767 * perf_event_disable_inatomic()
6768 * @pending_disable = CPU-B;
6769 * irq_work_queue(); // FAILS
6772 * perf_pending_irq()
6774 * But the event runs on CPU-B and wants disabling there.
6776 irq_work_queue_on(&event->pending_irq, cpu);
6779 static void perf_pending_irq(struct irq_work *entry)
6781 struct perf_event *event = container_of(entry, struct perf_event, pending_irq);
6785 * If we 'fail' here, that's OK, it means recursion is already disabled
6786 * and we won't recurse 'further'.
6788 rctx = perf_swevent_get_recursion_context();
6791 * The wakeup isn't bound to the context of the event -- it can happen
6792 * irrespective of where the event is.
6794 if (event->pending_wakeup) {
6795 event->pending_wakeup = 0;
6796 perf_event_wakeup(event);
6799 __perf_pending_irq(event);
6802 perf_swevent_put_recursion_context(rctx);
6805 static void perf_pending_task(struct callback_head *head)
6807 struct perf_event *event = container_of(head, struct perf_event, pending_task);
6811 * If we 'fail' here, that's OK, it means recursion is already disabled
6812 * and we won't recurse 'further'.
6814 preempt_disable_notrace();
6815 rctx = perf_swevent_get_recursion_context();
6817 if (event->pending_work) {
6818 event->pending_work = 0;
6819 perf_sigtrap(event);
6820 local_dec(&event->ctx->nr_pending);
6824 perf_swevent_put_recursion_context(rctx);
6825 preempt_enable_notrace();
6830 #ifdef CONFIG_GUEST_PERF_EVENTS
6831 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6833 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6834 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6835 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6837 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6839 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6842 rcu_assign_pointer(perf_guest_cbs, cbs);
6843 static_call_update(__perf_guest_state, cbs->state);
6844 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6846 /* Implementing ->handle_intel_pt_intr is optional. */
6847 if (cbs->handle_intel_pt_intr)
6848 static_call_update(__perf_guest_handle_intel_pt_intr,
6849 cbs->handle_intel_pt_intr);
6851 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6853 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6855 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6858 rcu_assign_pointer(perf_guest_cbs, NULL);
6859 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6860 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6861 static_call_update(__perf_guest_handle_intel_pt_intr,
6862 (void *)&__static_call_return0);
6865 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6869 perf_output_sample_regs(struct perf_output_handle *handle,
6870 struct pt_regs *regs, u64 mask)
6873 DECLARE_BITMAP(_mask, 64);
6875 bitmap_from_u64(_mask, mask);
6876 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6879 val = perf_reg_value(regs, bit);
6880 perf_output_put(handle, val);
6884 static void perf_sample_regs_user(struct perf_regs *regs_user,
6885 struct pt_regs *regs)
6887 if (user_mode(regs)) {
6888 regs_user->abi = perf_reg_abi(current);
6889 regs_user->regs = regs;
6890 } else if (!(current->flags & PF_KTHREAD)) {
6891 perf_get_regs_user(regs_user, regs);
6893 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6894 regs_user->regs = NULL;
6898 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6899 struct pt_regs *regs)
6901 regs_intr->regs = regs;
6902 regs_intr->abi = perf_reg_abi(current);
6907 * Get remaining task size from user stack pointer.
6909 * It'd be better to take stack vma map and limit this more
6910 * precisely, but there's no way to get it safely under interrupt,
6911 * so using TASK_SIZE as limit.
6913 static u64 perf_ustack_task_size(struct pt_regs *regs)
6915 unsigned long addr = perf_user_stack_pointer(regs);
6917 if (!addr || addr >= TASK_SIZE)
6920 return TASK_SIZE - addr;
6924 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6925 struct pt_regs *regs)
6929 /* No regs, no stack pointer, no dump. */
6934 * Check if we fit in with the requested stack size into the:
6936 * If we don't, we limit the size to the TASK_SIZE.
6938 * - remaining sample size
6939 * If we don't, we customize the stack size to
6940 * fit in to the remaining sample size.
6943 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6944 stack_size = min(stack_size, (u16) task_size);
6946 /* Current header size plus static size and dynamic size. */
6947 header_size += 2 * sizeof(u64);
6949 /* Do we fit in with the current stack dump size? */
6950 if ((u16) (header_size + stack_size) < header_size) {
6952 * If we overflow the maximum size for the sample,
6953 * we customize the stack dump size to fit in.
6955 stack_size = USHRT_MAX - header_size - sizeof(u64);
6956 stack_size = round_up(stack_size, sizeof(u64));
6963 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6964 struct pt_regs *regs)
6966 /* Case of a kernel thread, nothing to dump */
6969 perf_output_put(handle, size);
6978 * - the size requested by user or the best one we can fit
6979 * in to the sample max size
6981 * - user stack dump data
6983 * - the actual dumped size
6987 perf_output_put(handle, dump_size);
6990 sp = perf_user_stack_pointer(regs);
6991 rem = __output_copy_user(handle, (void *) sp, dump_size);
6992 dyn_size = dump_size - rem;
6994 perf_output_skip(handle, rem);
6997 perf_output_put(handle, dyn_size);
7001 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
7002 struct perf_sample_data *data,
7005 struct perf_event *sampler = event->aux_event;
7006 struct perf_buffer *rb;
7013 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
7016 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
7019 rb = ring_buffer_get(sampler);
7024 * If this is an NMI hit inside sampling code, don't take
7025 * the sample. See also perf_aux_sample_output().
7027 if (READ_ONCE(rb->aux_in_sampling)) {
7030 size = min_t(size_t, size, perf_aux_size(rb));
7031 data->aux_size = ALIGN(size, sizeof(u64));
7033 ring_buffer_put(rb);
7036 return data->aux_size;
7039 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
7040 struct perf_event *event,
7041 struct perf_output_handle *handle,
7044 unsigned long flags;
7048 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
7049 * paths. If we start calling them in NMI context, they may race with
7050 * the IRQ ones, that is, for example, re-starting an event that's just
7051 * been stopped, which is why we're using a separate callback that
7052 * doesn't change the event state.
7054 * IRQs need to be disabled to prevent IPIs from racing with us.
7056 local_irq_save(flags);
7058 * Guard against NMI hits inside the critical section;
7059 * see also perf_prepare_sample_aux().
7061 WRITE_ONCE(rb->aux_in_sampling, 1);
7064 ret = event->pmu->snapshot_aux(event, handle, size);
7067 WRITE_ONCE(rb->aux_in_sampling, 0);
7068 local_irq_restore(flags);
7073 static void perf_aux_sample_output(struct perf_event *event,
7074 struct perf_output_handle *handle,
7075 struct perf_sample_data *data)
7077 struct perf_event *sampler = event->aux_event;
7078 struct perf_buffer *rb;
7082 if (WARN_ON_ONCE(!sampler || !data->aux_size))
7085 rb = ring_buffer_get(sampler);
7089 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
7092 * An error here means that perf_output_copy() failed (returned a
7093 * non-zero surplus that it didn't copy), which in its current
7094 * enlightened implementation is not possible. If that changes, we'd
7097 if (WARN_ON_ONCE(size < 0))
7101 * The pad comes from ALIGN()ing data->aux_size up to u64 in
7102 * perf_prepare_sample_aux(), so should not be more than that.
7104 pad = data->aux_size - size;
7105 if (WARN_ON_ONCE(pad >= sizeof(u64)))
7110 perf_output_copy(handle, &zero, pad);
7114 ring_buffer_put(rb);
7118 * A set of common sample data types saved even for non-sample records
7119 * when event->attr.sample_id_all is set.
7121 #define PERF_SAMPLE_ID_ALL (PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \
7122 PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID | \
7123 PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER)
7125 static void __perf_event_header__init_id(struct perf_sample_data *data,
7126 struct perf_event *event,
7129 data->type = event->attr.sample_type;
7130 data->sample_flags |= data->type & PERF_SAMPLE_ID_ALL;
7132 if (sample_type & PERF_SAMPLE_TID) {
7133 /* namespace issues */
7134 data->tid_entry.pid = perf_event_pid(event, current);
7135 data->tid_entry.tid = perf_event_tid(event, current);
7138 if (sample_type & PERF_SAMPLE_TIME)
7139 data->time = perf_event_clock(event);
7141 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
7142 data->id = primary_event_id(event);
7144 if (sample_type & PERF_SAMPLE_STREAM_ID)
7145 data->stream_id = event->id;
7147 if (sample_type & PERF_SAMPLE_CPU) {
7148 data->cpu_entry.cpu = raw_smp_processor_id();
7149 data->cpu_entry.reserved = 0;
7153 void perf_event_header__init_id(struct perf_event_header *header,
7154 struct perf_sample_data *data,
7155 struct perf_event *event)
7157 if (event->attr.sample_id_all) {
7158 header->size += event->id_header_size;
7159 __perf_event_header__init_id(data, event, event->attr.sample_type);
7163 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
7164 struct perf_sample_data *data)
7166 u64 sample_type = data->type;
7168 if (sample_type & PERF_SAMPLE_TID)
7169 perf_output_put(handle, data->tid_entry);
7171 if (sample_type & PERF_SAMPLE_TIME)
7172 perf_output_put(handle, data->time);
7174 if (sample_type & PERF_SAMPLE_ID)
7175 perf_output_put(handle, data->id);
7177 if (sample_type & PERF_SAMPLE_STREAM_ID)
7178 perf_output_put(handle, data->stream_id);
7180 if (sample_type & PERF_SAMPLE_CPU)
7181 perf_output_put(handle, data->cpu_entry);
7183 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7184 perf_output_put(handle, data->id);
7187 void perf_event__output_id_sample(struct perf_event *event,
7188 struct perf_output_handle *handle,
7189 struct perf_sample_data *sample)
7191 if (event->attr.sample_id_all)
7192 __perf_event__output_id_sample(handle, sample);
7195 static void perf_output_read_one(struct perf_output_handle *handle,
7196 struct perf_event *event,
7197 u64 enabled, u64 running)
7199 u64 read_format = event->attr.read_format;
7203 values[n++] = perf_event_count(event);
7204 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
7205 values[n++] = enabled +
7206 atomic64_read(&event->child_total_time_enabled);
7208 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
7209 values[n++] = running +
7210 atomic64_read(&event->child_total_time_running);
7212 if (read_format & PERF_FORMAT_ID)
7213 values[n++] = primary_event_id(event);
7214 if (read_format & PERF_FORMAT_LOST)
7215 values[n++] = atomic64_read(&event->lost_samples);
7217 __output_copy(handle, values, n * sizeof(u64));
7220 static void perf_output_read_group(struct perf_output_handle *handle,
7221 struct perf_event *event,
7222 u64 enabled, u64 running)
7224 struct perf_event *leader = event->group_leader, *sub;
7225 u64 read_format = event->attr.read_format;
7226 unsigned long flags;
7231 * Disabling interrupts avoids all counter scheduling
7232 * (context switches, timer based rotation and IPIs).
7234 local_irq_save(flags);
7236 values[n++] = 1 + leader->nr_siblings;
7238 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
7239 values[n++] = enabled;
7241 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
7242 values[n++] = running;
7244 if ((leader != event) &&
7245 (leader->state == PERF_EVENT_STATE_ACTIVE))
7246 leader->pmu->read(leader);
7248 values[n++] = perf_event_count(leader);
7249 if (read_format & PERF_FORMAT_ID)
7250 values[n++] = primary_event_id(leader);
7251 if (read_format & PERF_FORMAT_LOST)
7252 values[n++] = atomic64_read(&leader->lost_samples);
7254 __output_copy(handle, values, n * sizeof(u64));
7256 for_each_sibling_event(sub, leader) {
7259 if ((sub != event) &&
7260 (sub->state == PERF_EVENT_STATE_ACTIVE))
7261 sub->pmu->read(sub);
7263 values[n++] = perf_event_count(sub);
7264 if (read_format & PERF_FORMAT_ID)
7265 values[n++] = primary_event_id(sub);
7266 if (read_format & PERF_FORMAT_LOST)
7267 values[n++] = atomic64_read(&sub->lost_samples);
7269 __output_copy(handle, values, n * sizeof(u64));
7272 local_irq_restore(flags);
7275 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7276 PERF_FORMAT_TOTAL_TIME_RUNNING)
7279 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7281 * The problem is that its both hard and excessively expensive to iterate the
7282 * child list, not to mention that its impossible to IPI the children running
7283 * on another CPU, from interrupt/NMI context.
7285 static void perf_output_read(struct perf_output_handle *handle,
7286 struct perf_event *event)
7288 u64 enabled = 0, running = 0, now;
7289 u64 read_format = event->attr.read_format;
7292 * compute total_time_enabled, total_time_running
7293 * based on snapshot values taken when the event
7294 * was last scheduled in.
7296 * we cannot simply called update_context_time()
7297 * because of locking issue as we are called in
7300 if (read_format & PERF_FORMAT_TOTAL_TIMES)
7301 calc_timer_values(event, &now, &enabled, &running);
7303 if (event->attr.read_format & PERF_FORMAT_GROUP)
7304 perf_output_read_group(handle, event, enabled, running);
7306 perf_output_read_one(handle, event, enabled, running);
7309 void perf_output_sample(struct perf_output_handle *handle,
7310 struct perf_event_header *header,
7311 struct perf_sample_data *data,
7312 struct perf_event *event)
7314 u64 sample_type = data->type;
7316 perf_output_put(handle, *header);
7318 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7319 perf_output_put(handle, data->id);
7321 if (sample_type & PERF_SAMPLE_IP)
7322 perf_output_put(handle, data->ip);
7324 if (sample_type & PERF_SAMPLE_TID)
7325 perf_output_put(handle, data->tid_entry);
7327 if (sample_type & PERF_SAMPLE_TIME)
7328 perf_output_put(handle, data->time);
7330 if (sample_type & PERF_SAMPLE_ADDR)
7331 perf_output_put(handle, data->addr);
7333 if (sample_type & PERF_SAMPLE_ID)
7334 perf_output_put(handle, data->id);
7336 if (sample_type & PERF_SAMPLE_STREAM_ID)
7337 perf_output_put(handle, data->stream_id);
7339 if (sample_type & PERF_SAMPLE_CPU)
7340 perf_output_put(handle, data->cpu_entry);
7342 if (sample_type & PERF_SAMPLE_PERIOD)
7343 perf_output_put(handle, data->period);
7345 if (sample_type & PERF_SAMPLE_READ)
7346 perf_output_read(handle, event);
7348 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7351 size += data->callchain->nr;
7352 size *= sizeof(u64);
7353 __output_copy(handle, data->callchain, size);
7356 if (sample_type & PERF_SAMPLE_RAW) {
7357 struct perf_raw_record *raw = data->raw;
7360 struct perf_raw_frag *frag = &raw->frag;
7362 perf_output_put(handle, raw->size);
7365 __output_custom(handle, frag->copy,
7366 frag->data, frag->size);
7368 __output_copy(handle, frag->data,
7371 if (perf_raw_frag_last(frag))
7376 __output_skip(handle, NULL, frag->pad);
7382 .size = sizeof(u32),
7385 perf_output_put(handle, raw);
7389 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7390 if (data->br_stack) {
7393 size = data->br_stack->nr
7394 * sizeof(struct perf_branch_entry);
7396 perf_output_put(handle, data->br_stack->nr);
7397 if (branch_sample_hw_index(event))
7398 perf_output_put(handle, data->br_stack->hw_idx);
7399 perf_output_copy(handle, data->br_stack->entries, size);
7401 * Add the extension space which is appended
7402 * right after the struct perf_branch_stack.
7404 if (data->br_stack_cntr) {
7405 size = data->br_stack->nr * sizeof(u64);
7406 perf_output_copy(handle, data->br_stack_cntr, size);
7410 * we always store at least the value of nr
7413 perf_output_put(handle, nr);
7417 if (sample_type & PERF_SAMPLE_REGS_USER) {
7418 u64 abi = data->regs_user.abi;
7421 * If there are no regs to dump, notice it through
7422 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7424 perf_output_put(handle, abi);
7427 u64 mask = event->attr.sample_regs_user;
7428 perf_output_sample_regs(handle,
7429 data->regs_user.regs,
7434 if (sample_type & PERF_SAMPLE_STACK_USER) {
7435 perf_output_sample_ustack(handle,
7436 data->stack_user_size,
7437 data->regs_user.regs);
7440 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7441 perf_output_put(handle, data->weight.full);
7443 if (sample_type & PERF_SAMPLE_DATA_SRC)
7444 perf_output_put(handle, data->data_src.val);
7446 if (sample_type & PERF_SAMPLE_TRANSACTION)
7447 perf_output_put(handle, data->txn);
7449 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7450 u64 abi = data->regs_intr.abi;
7452 * If there are no regs to dump, notice it through
7453 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7455 perf_output_put(handle, abi);
7458 u64 mask = event->attr.sample_regs_intr;
7460 perf_output_sample_regs(handle,
7461 data->regs_intr.regs,
7466 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7467 perf_output_put(handle, data->phys_addr);
7469 if (sample_type & PERF_SAMPLE_CGROUP)
7470 perf_output_put(handle, data->cgroup);
7472 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7473 perf_output_put(handle, data->data_page_size);
7475 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7476 perf_output_put(handle, data->code_page_size);
7478 if (sample_type & PERF_SAMPLE_AUX) {
7479 perf_output_put(handle, data->aux_size);
7482 perf_aux_sample_output(event, handle, data);
7485 if (!event->attr.watermark) {
7486 int wakeup_events = event->attr.wakeup_events;
7488 if (wakeup_events) {
7489 struct perf_buffer *rb = handle->rb;
7490 int events = local_inc_return(&rb->events);
7492 if (events >= wakeup_events) {
7493 local_sub(wakeup_events, &rb->events);
7494 local_inc(&rb->wakeup);
7500 static u64 perf_virt_to_phys(u64 virt)
7507 if (virt >= TASK_SIZE) {
7508 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7509 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7510 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7511 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7514 * Walking the pages tables for user address.
7515 * Interrupts are disabled, so it prevents any tear down
7516 * of the page tables.
7517 * Try IRQ-safe get_user_page_fast_only first.
7518 * If failed, leave phys_addr as 0.
7520 if (current->mm != NULL) {
7523 pagefault_disable();
7524 if (get_user_page_fast_only(virt, 0, &p)) {
7525 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7536 * Return the pagetable size of a given virtual address.
7538 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7542 #ifdef CONFIG_HAVE_FAST_GUP
7549 pgdp = pgd_offset(mm, addr);
7550 pgd = READ_ONCE(*pgdp);
7555 return pgd_leaf_size(pgd);
7557 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7558 p4d = READ_ONCE(*p4dp);
7559 if (!p4d_present(p4d))
7563 return p4d_leaf_size(p4d);
7565 pudp = pud_offset_lockless(p4dp, p4d, addr);
7566 pud = READ_ONCE(*pudp);
7567 if (!pud_present(pud))
7571 return pud_leaf_size(pud);
7573 pmdp = pmd_offset_lockless(pudp, pud, addr);
7575 pmd = pmdp_get_lockless(pmdp);
7576 if (!pmd_present(pmd))
7580 return pmd_leaf_size(pmd);
7582 ptep = pte_offset_map(&pmd, addr);
7586 pte = ptep_get_lockless(ptep);
7587 if (pte_present(pte))
7588 size = pte_leaf_size(pte);
7590 #endif /* CONFIG_HAVE_FAST_GUP */
7595 static u64 perf_get_page_size(unsigned long addr)
7597 struct mm_struct *mm;
7598 unsigned long flags;
7605 * Software page-table walkers must disable IRQs,
7606 * which prevents any tear down of the page tables.
7608 local_irq_save(flags);
7613 * For kernel threads and the like, use init_mm so that
7614 * we can find kernel memory.
7619 size = perf_get_pgtable_size(mm, addr);
7621 local_irq_restore(flags);
7626 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7628 struct perf_callchain_entry *
7629 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7631 bool kernel = !event->attr.exclude_callchain_kernel;
7632 bool user = !event->attr.exclude_callchain_user;
7633 /* Disallow cross-task user callchains. */
7634 bool crosstask = event->ctx->task && event->ctx->task != current;
7635 const u32 max_stack = event->attr.sample_max_stack;
7636 struct perf_callchain_entry *callchain;
7638 if (!kernel && !user)
7639 return &__empty_callchain;
7641 callchain = get_perf_callchain(regs, 0, kernel, user,
7642 max_stack, crosstask, true);
7643 return callchain ?: &__empty_callchain;
7646 static __always_inline u64 __cond_set(u64 flags, u64 s, u64 d)
7648 return d * !!(flags & s);
7651 void perf_prepare_sample(struct perf_sample_data *data,
7652 struct perf_event *event,
7653 struct pt_regs *regs)
7655 u64 sample_type = event->attr.sample_type;
7656 u64 filtered_sample_type;
7659 * Add the sample flags that are dependent to others. And clear the
7660 * sample flags that have already been done by the PMU driver.
7662 filtered_sample_type = sample_type;
7663 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_CODE_PAGE_SIZE,
7665 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_DATA_PAGE_SIZE |
7666 PERF_SAMPLE_PHYS_ADDR, PERF_SAMPLE_ADDR);
7667 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_STACK_USER,
7668 PERF_SAMPLE_REGS_USER);
7669 filtered_sample_type &= ~data->sample_flags;
7671 if (filtered_sample_type == 0) {
7672 /* Make sure it has the correct data->type for output */
7673 data->type = event->attr.sample_type;
7677 __perf_event_header__init_id(data, event, filtered_sample_type);
7679 if (filtered_sample_type & PERF_SAMPLE_IP) {
7680 data->ip = perf_instruction_pointer(regs);
7681 data->sample_flags |= PERF_SAMPLE_IP;
7684 if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
7685 perf_sample_save_callchain(data, event, regs);
7687 if (filtered_sample_type & PERF_SAMPLE_RAW) {
7689 data->dyn_size += sizeof(u64);
7690 data->sample_flags |= PERF_SAMPLE_RAW;
7693 if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) {
7694 data->br_stack = NULL;
7695 data->dyn_size += sizeof(u64);
7696 data->sample_flags |= PERF_SAMPLE_BRANCH_STACK;
7699 if (filtered_sample_type & PERF_SAMPLE_REGS_USER)
7700 perf_sample_regs_user(&data->regs_user, regs);
7703 * It cannot use the filtered_sample_type here as REGS_USER can be set
7704 * by STACK_USER (using __cond_set() above) and we don't want to update
7705 * the dyn_size if it's not requested by users.
7707 if ((sample_type & ~data->sample_flags) & PERF_SAMPLE_REGS_USER) {
7708 /* regs dump ABI info */
7709 int size = sizeof(u64);
7711 if (data->regs_user.regs) {
7712 u64 mask = event->attr.sample_regs_user;
7713 size += hweight64(mask) * sizeof(u64);
7716 data->dyn_size += size;
7717 data->sample_flags |= PERF_SAMPLE_REGS_USER;
7720 if (filtered_sample_type & PERF_SAMPLE_STACK_USER) {
7722 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7723 * processed as the last one or have additional check added
7724 * in case new sample type is added, because we could eat
7725 * up the rest of the sample size.
7727 u16 stack_size = event->attr.sample_stack_user;
7728 u16 header_size = perf_sample_data_size(data, event);
7729 u16 size = sizeof(u64);
7731 stack_size = perf_sample_ustack_size(stack_size, header_size,
7732 data->regs_user.regs);
7735 * If there is something to dump, add space for the dump
7736 * itself and for the field that tells the dynamic size,
7737 * which is how many have been actually dumped.
7740 size += sizeof(u64) + stack_size;
7742 data->stack_user_size = stack_size;
7743 data->dyn_size += size;
7744 data->sample_flags |= PERF_SAMPLE_STACK_USER;
7747 if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) {
7748 data->weight.full = 0;
7749 data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE;
7752 if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) {
7753 data->data_src.val = PERF_MEM_NA;
7754 data->sample_flags |= PERF_SAMPLE_DATA_SRC;
7757 if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) {
7759 data->sample_flags |= PERF_SAMPLE_TRANSACTION;
7762 if (filtered_sample_type & PERF_SAMPLE_ADDR) {
7764 data->sample_flags |= PERF_SAMPLE_ADDR;
7767 if (filtered_sample_type & PERF_SAMPLE_REGS_INTR) {
7768 /* regs dump ABI info */
7769 int size = sizeof(u64);
7771 perf_sample_regs_intr(&data->regs_intr, regs);
7773 if (data->regs_intr.regs) {
7774 u64 mask = event->attr.sample_regs_intr;
7776 size += hweight64(mask) * sizeof(u64);
7779 data->dyn_size += size;
7780 data->sample_flags |= PERF_SAMPLE_REGS_INTR;
7783 if (filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) {
7784 data->phys_addr = perf_virt_to_phys(data->addr);
7785 data->sample_flags |= PERF_SAMPLE_PHYS_ADDR;
7788 #ifdef CONFIG_CGROUP_PERF
7789 if (filtered_sample_type & PERF_SAMPLE_CGROUP) {
7790 struct cgroup *cgrp;
7792 /* protected by RCU */
7793 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7794 data->cgroup = cgroup_id(cgrp);
7795 data->sample_flags |= PERF_SAMPLE_CGROUP;
7800 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7801 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7802 * but the value will not dump to the userspace.
7804 if (filtered_sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) {
7805 data->data_page_size = perf_get_page_size(data->addr);
7806 data->sample_flags |= PERF_SAMPLE_DATA_PAGE_SIZE;
7809 if (filtered_sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) {
7810 data->code_page_size = perf_get_page_size(data->ip);
7811 data->sample_flags |= PERF_SAMPLE_CODE_PAGE_SIZE;
7814 if (filtered_sample_type & PERF_SAMPLE_AUX) {
7816 u16 header_size = perf_sample_data_size(data, event);
7818 header_size += sizeof(u64); /* size */
7821 * Given the 16bit nature of header::size, an AUX sample can
7822 * easily overflow it, what with all the preceding sample bits.
7823 * Make sure this doesn't happen by using up to U16_MAX bytes
7824 * per sample in total (rounded down to 8 byte boundary).
7826 size = min_t(size_t, U16_MAX - header_size,
7827 event->attr.aux_sample_size);
7828 size = rounddown(size, 8);
7829 size = perf_prepare_sample_aux(event, data, size);
7831 WARN_ON_ONCE(size + header_size > U16_MAX);
7832 data->dyn_size += size + sizeof(u64); /* size above */
7833 data->sample_flags |= PERF_SAMPLE_AUX;
7837 void perf_prepare_header(struct perf_event_header *header,
7838 struct perf_sample_data *data,
7839 struct perf_event *event,
7840 struct pt_regs *regs)
7842 header->type = PERF_RECORD_SAMPLE;
7843 header->size = perf_sample_data_size(data, event);
7844 header->misc = perf_misc_flags(regs);
7847 * If you're adding more sample types here, you likely need to do
7848 * something about the overflowing header::size, like repurpose the
7849 * lowest 3 bits of size, which should be always zero at the moment.
7850 * This raises a more important question, do we really need 512k sized
7851 * samples and why, so good argumentation is in order for whatever you
7854 WARN_ON_ONCE(header->size & 7);
7857 static __always_inline int
7858 __perf_event_output(struct perf_event *event,
7859 struct perf_sample_data *data,
7860 struct pt_regs *regs,
7861 int (*output_begin)(struct perf_output_handle *,
7862 struct perf_sample_data *,
7863 struct perf_event *,
7866 struct perf_output_handle handle;
7867 struct perf_event_header header;
7870 /* protect the callchain buffers */
7873 perf_prepare_sample(data, event, regs);
7874 perf_prepare_header(&header, data, event, regs);
7876 err = output_begin(&handle, data, event, header.size);
7880 perf_output_sample(&handle, &header, data, event);
7882 perf_output_end(&handle);
7890 perf_event_output_forward(struct perf_event *event,
7891 struct perf_sample_data *data,
7892 struct pt_regs *regs)
7894 __perf_event_output(event, data, regs, perf_output_begin_forward);
7898 perf_event_output_backward(struct perf_event *event,
7899 struct perf_sample_data *data,
7900 struct pt_regs *regs)
7902 __perf_event_output(event, data, regs, perf_output_begin_backward);
7906 perf_event_output(struct perf_event *event,
7907 struct perf_sample_data *data,
7908 struct pt_regs *regs)
7910 return __perf_event_output(event, data, regs, perf_output_begin);
7917 struct perf_read_event {
7918 struct perf_event_header header;
7925 perf_event_read_event(struct perf_event *event,
7926 struct task_struct *task)
7928 struct perf_output_handle handle;
7929 struct perf_sample_data sample;
7930 struct perf_read_event read_event = {
7932 .type = PERF_RECORD_READ,
7934 .size = sizeof(read_event) + event->read_size,
7936 .pid = perf_event_pid(event, task),
7937 .tid = perf_event_tid(event, task),
7941 perf_event_header__init_id(&read_event.header, &sample, event);
7942 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7946 perf_output_put(&handle, read_event);
7947 perf_output_read(&handle, event);
7948 perf_event__output_id_sample(event, &handle, &sample);
7950 perf_output_end(&handle);
7953 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7956 perf_iterate_ctx(struct perf_event_context *ctx,
7957 perf_iterate_f output,
7958 void *data, bool all)
7960 struct perf_event *event;
7962 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7964 if (event->state < PERF_EVENT_STATE_INACTIVE)
7966 if (!event_filter_match(event))
7970 output(event, data);
7974 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7976 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7977 struct perf_event *event;
7979 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7981 * Skip events that are not fully formed yet; ensure that
7982 * if we observe event->ctx, both event and ctx will be
7983 * complete enough. See perf_install_in_context().
7985 if (!smp_load_acquire(&event->ctx))
7988 if (event->state < PERF_EVENT_STATE_INACTIVE)
7990 if (!event_filter_match(event))
7992 output(event, data);
7997 * Iterate all events that need to receive side-band events.
7999 * For new callers; ensure that account_pmu_sb_event() includes
8000 * your event, otherwise it might not get delivered.
8003 perf_iterate_sb(perf_iterate_f output, void *data,
8004 struct perf_event_context *task_ctx)
8006 struct perf_event_context *ctx;
8012 * If we have task_ctx != NULL we only notify the task context itself.
8013 * The task_ctx is set only for EXIT events before releasing task
8017 perf_iterate_ctx(task_ctx, output, data, false);
8021 perf_iterate_sb_cpu(output, data);
8023 ctx = rcu_dereference(current->perf_event_ctxp);
8025 perf_iterate_ctx(ctx, output, data, false);
8032 * Clear all file-based filters at exec, they'll have to be
8033 * re-instated when/if these objects are mmapped again.
8035 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
8037 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8038 struct perf_addr_filter *filter;
8039 unsigned int restart = 0, count = 0;
8040 unsigned long flags;
8042 if (!has_addr_filter(event))
8045 raw_spin_lock_irqsave(&ifh->lock, flags);
8046 list_for_each_entry(filter, &ifh->list, entry) {
8047 if (filter->path.dentry) {
8048 event->addr_filter_ranges[count].start = 0;
8049 event->addr_filter_ranges[count].size = 0;
8057 event->addr_filters_gen++;
8058 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8061 perf_event_stop(event, 1);
8064 void perf_event_exec(void)
8066 struct perf_event_context *ctx;
8068 ctx = perf_pin_task_context(current);
8072 perf_event_enable_on_exec(ctx);
8073 perf_event_remove_on_exec(ctx);
8074 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
8076 perf_unpin_context(ctx);
8080 struct remote_output {
8081 struct perf_buffer *rb;
8085 static void __perf_event_output_stop(struct perf_event *event, void *data)
8087 struct perf_event *parent = event->parent;
8088 struct remote_output *ro = data;
8089 struct perf_buffer *rb = ro->rb;
8090 struct stop_event_data sd = {
8094 if (!has_aux(event))
8101 * In case of inheritance, it will be the parent that links to the
8102 * ring-buffer, but it will be the child that's actually using it.
8104 * We are using event::rb to determine if the event should be stopped,
8105 * however this may race with ring_buffer_attach() (through set_output),
8106 * which will make us skip the event that actually needs to be stopped.
8107 * So ring_buffer_attach() has to stop an aux event before re-assigning
8110 if (rcu_dereference(parent->rb) == rb)
8111 ro->err = __perf_event_stop(&sd);
8114 static int __perf_pmu_output_stop(void *info)
8116 struct perf_event *event = info;
8117 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
8118 struct remote_output ro = {
8123 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
8124 if (cpuctx->task_ctx)
8125 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
8132 static void perf_pmu_output_stop(struct perf_event *event)
8134 struct perf_event *iter;
8139 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
8141 * For per-CPU events, we need to make sure that neither they
8142 * nor their children are running; for cpu==-1 events it's
8143 * sufficient to stop the event itself if it's active, since
8144 * it can't have children.
8148 cpu = READ_ONCE(iter->oncpu);
8153 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
8154 if (err == -EAGAIN) {
8163 * task tracking -- fork/exit
8165 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
8168 struct perf_task_event {
8169 struct task_struct *task;
8170 struct perf_event_context *task_ctx;
8173 struct perf_event_header header;
8183 static int perf_event_task_match(struct perf_event *event)
8185 return event->attr.comm || event->attr.mmap ||
8186 event->attr.mmap2 || event->attr.mmap_data ||
8190 static void perf_event_task_output(struct perf_event *event,
8193 struct perf_task_event *task_event = data;
8194 struct perf_output_handle handle;
8195 struct perf_sample_data sample;
8196 struct task_struct *task = task_event->task;
8197 int ret, size = task_event->event_id.header.size;
8199 if (!perf_event_task_match(event))
8202 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
8204 ret = perf_output_begin(&handle, &sample, event,
8205 task_event->event_id.header.size);
8209 task_event->event_id.pid = perf_event_pid(event, task);
8210 task_event->event_id.tid = perf_event_tid(event, task);
8212 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
8213 task_event->event_id.ppid = perf_event_pid(event,
8215 task_event->event_id.ptid = perf_event_pid(event,
8217 } else { /* PERF_RECORD_FORK */
8218 task_event->event_id.ppid = perf_event_pid(event, current);
8219 task_event->event_id.ptid = perf_event_tid(event, current);
8222 task_event->event_id.time = perf_event_clock(event);
8224 perf_output_put(&handle, task_event->event_id);
8226 perf_event__output_id_sample(event, &handle, &sample);
8228 perf_output_end(&handle);
8230 task_event->event_id.header.size = size;
8233 static void perf_event_task(struct task_struct *task,
8234 struct perf_event_context *task_ctx,
8237 struct perf_task_event task_event;
8239 if (!atomic_read(&nr_comm_events) &&
8240 !atomic_read(&nr_mmap_events) &&
8241 !atomic_read(&nr_task_events))
8244 task_event = (struct perf_task_event){
8246 .task_ctx = task_ctx,
8249 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
8251 .size = sizeof(task_event.event_id),
8261 perf_iterate_sb(perf_event_task_output,
8266 void perf_event_fork(struct task_struct *task)
8268 perf_event_task(task, NULL, 1);
8269 perf_event_namespaces(task);
8276 struct perf_comm_event {
8277 struct task_struct *task;
8282 struct perf_event_header header;
8289 static int perf_event_comm_match(struct perf_event *event)
8291 return event->attr.comm;
8294 static void perf_event_comm_output(struct perf_event *event,
8297 struct perf_comm_event *comm_event = data;
8298 struct perf_output_handle handle;
8299 struct perf_sample_data sample;
8300 int size = comm_event->event_id.header.size;
8303 if (!perf_event_comm_match(event))
8306 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
8307 ret = perf_output_begin(&handle, &sample, event,
8308 comm_event->event_id.header.size);
8313 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8314 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8316 perf_output_put(&handle, comm_event->event_id);
8317 __output_copy(&handle, comm_event->comm,
8318 comm_event->comm_size);
8320 perf_event__output_id_sample(event, &handle, &sample);
8322 perf_output_end(&handle);
8324 comm_event->event_id.header.size = size;
8327 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8329 char comm[TASK_COMM_LEN];
8332 memset(comm, 0, sizeof(comm));
8333 strscpy(comm, comm_event->task->comm, sizeof(comm));
8334 size = ALIGN(strlen(comm)+1, sizeof(u64));
8336 comm_event->comm = comm;
8337 comm_event->comm_size = size;
8339 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8341 perf_iterate_sb(perf_event_comm_output,
8346 void perf_event_comm(struct task_struct *task, bool exec)
8348 struct perf_comm_event comm_event;
8350 if (!atomic_read(&nr_comm_events))
8353 comm_event = (struct perf_comm_event){
8359 .type = PERF_RECORD_COMM,
8360 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8368 perf_event_comm_event(&comm_event);
8372 * namespaces tracking
8375 struct perf_namespaces_event {
8376 struct task_struct *task;
8379 struct perf_event_header header;
8384 struct perf_ns_link_info link_info[NR_NAMESPACES];
8388 static int perf_event_namespaces_match(struct perf_event *event)
8390 return event->attr.namespaces;
8393 static void perf_event_namespaces_output(struct perf_event *event,
8396 struct perf_namespaces_event *namespaces_event = data;
8397 struct perf_output_handle handle;
8398 struct perf_sample_data sample;
8399 u16 header_size = namespaces_event->event_id.header.size;
8402 if (!perf_event_namespaces_match(event))
8405 perf_event_header__init_id(&namespaces_event->event_id.header,
8407 ret = perf_output_begin(&handle, &sample, event,
8408 namespaces_event->event_id.header.size);
8412 namespaces_event->event_id.pid = perf_event_pid(event,
8413 namespaces_event->task);
8414 namespaces_event->event_id.tid = perf_event_tid(event,
8415 namespaces_event->task);
8417 perf_output_put(&handle, namespaces_event->event_id);
8419 perf_event__output_id_sample(event, &handle, &sample);
8421 perf_output_end(&handle);
8423 namespaces_event->event_id.header.size = header_size;
8426 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8427 struct task_struct *task,
8428 const struct proc_ns_operations *ns_ops)
8430 struct path ns_path;
8431 struct inode *ns_inode;
8434 error = ns_get_path(&ns_path, task, ns_ops);
8436 ns_inode = ns_path.dentry->d_inode;
8437 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8438 ns_link_info->ino = ns_inode->i_ino;
8443 void perf_event_namespaces(struct task_struct *task)
8445 struct perf_namespaces_event namespaces_event;
8446 struct perf_ns_link_info *ns_link_info;
8448 if (!atomic_read(&nr_namespaces_events))
8451 namespaces_event = (struct perf_namespaces_event){
8455 .type = PERF_RECORD_NAMESPACES,
8457 .size = sizeof(namespaces_event.event_id),
8461 .nr_namespaces = NR_NAMESPACES,
8462 /* .link_info[NR_NAMESPACES] */
8466 ns_link_info = namespaces_event.event_id.link_info;
8468 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8469 task, &mntns_operations);
8471 #ifdef CONFIG_USER_NS
8472 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8473 task, &userns_operations);
8475 #ifdef CONFIG_NET_NS
8476 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8477 task, &netns_operations);
8479 #ifdef CONFIG_UTS_NS
8480 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8481 task, &utsns_operations);
8483 #ifdef CONFIG_IPC_NS
8484 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8485 task, &ipcns_operations);
8487 #ifdef CONFIG_PID_NS
8488 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8489 task, &pidns_operations);
8491 #ifdef CONFIG_CGROUPS
8492 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8493 task, &cgroupns_operations);
8496 perf_iterate_sb(perf_event_namespaces_output,
8504 #ifdef CONFIG_CGROUP_PERF
8506 struct perf_cgroup_event {
8510 struct perf_event_header header;
8516 static int perf_event_cgroup_match(struct perf_event *event)
8518 return event->attr.cgroup;
8521 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8523 struct perf_cgroup_event *cgroup_event = data;
8524 struct perf_output_handle handle;
8525 struct perf_sample_data sample;
8526 u16 header_size = cgroup_event->event_id.header.size;
8529 if (!perf_event_cgroup_match(event))
8532 perf_event_header__init_id(&cgroup_event->event_id.header,
8534 ret = perf_output_begin(&handle, &sample, event,
8535 cgroup_event->event_id.header.size);
8539 perf_output_put(&handle, cgroup_event->event_id);
8540 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8542 perf_event__output_id_sample(event, &handle, &sample);
8544 perf_output_end(&handle);
8546 cgroup_event->event_id.header.size = header_size;
8549 static void perf_event_cgroup(struct cgroup *cgrp)
8551 struct perf_cgroup_event cgroup_event;
8552 char path_enomem[16] = "//enomem";
8556 if (!atomic_read(&nr_cgroup_events))
8559 cgroup_event = (struct perf_cgroup_event){
8562 .type = PERF_RECORD_CGROUP,
8564 .size = sizeof(cgroup_event.event_id),
8566 .id = cgroup_id(cgrp),
8570 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8571 if (pathname == NULL) {
8572 cgroup_event.path = path_enomem;
8574 /* just to be sure to have enough space for alignment */
8575 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8576 cgroup_event.path = pathname;
8580 * Since our buffer works in 8 byte units we need to align our string
8581 * size to a multiple of 8. However, we must guarantee the tail end is
8582 * zero'd out to avoid leaking random bits to userspace.
8584 size = strlen(cgroup_event.path) + 1;
8585 while (!IS_ALIGNED(size, sizeof(u64)))
8586 cgroup_event.path[size++] = '\0';
8588 cgroup_event.event_id.header.size += size;
8589 cgroup_event.path_size = size;
8591 perf_iterate_sb(perf_event_cgroup_output,
8604 struct perf_mmap_event {
8605 struct vm_area_struct *vma;
8607 const char *file_name;
8613 u8 build_id[BUILD_ID_SIZE_MAX];
8617 struct perf_event_header header;
8627 static int perf_event_mmap_match(struct perf_event *event,
8630 struct perf_mmap_event *mmap_event = data;
8631 struct vm_area_struct *vma = mmap_event->vma;
8632 int executable = vma->vm_flags & VM_EXEC;
8634 return (!executable && event->attr.mmap_data) ||
8635 (executable && (event->attr.mmap || event->attr.mmap2));
8638 static void perf_event_mmap_output(struct perf_event *event,
8641 struct perf_mmap_event *mmap_event = data;
8642 struct perf_output_handle handle;
8643 struct perf_sample_data sample;
8644 int size = mmap_event->event_id.header.size;
8645 u32 type = mmap_event->event_id.header.type;
8649 if (!perf_event_mmap_match(event, data))
8652 if (event->attr.mmap2) {
8653 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8654 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8655 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8656 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8657 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8658 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8659 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8662 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8663 ret = perf_output_begin(&handle, &sample, event,
8664 mmap_event->event_id.header.size);
8668 mmap_event->event_id.pid = perf_event_pid(event, current);
8669 mmap_event->event_id.tid = perf_event_tid(event, current);
8671 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8673 if (event->attr.mmap2 && use_build_id)
8674 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8676 perf_output_put(&handle, mmap_event->event_id);
8678 if (event->attr.mmap2) {
8680 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8682 __output_copy(&handle, size, 4);
8683 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8685 perf_output_put(&handle, mmap_event->maj);
8686 perf_output_put(&handle, mmap_event->min);
8687 perf_output_put(&handle, mmap_event->ino);
8688 perf_output_put(&handle, mmap_event->ino_generation);
8690 perf_output_put(&handle, mmap_event->prot);
8691 perf_output_put(&handle, mmap_event->flags);
8694 __output_copy(&handle, mmap_event->file_name,
8695 mmap_event->file_size);
8697 perf_event__output_id_sample(event, &handle, &sample);
8699 perf_output_end(&handle);
8701 mmap_event->event_id.header.size = size;
8702 mmap_event->event_id.header.type = type;
8705 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8707 struct vm_area_struct *vma = mmap_event->vma;
8708 struct file *file = vma->vm_file;
8709 int maj = 0, min = 0;
8710 u64 ino = 0, gen = 0;
8711 u32 prot = 0, flags = 0;
8717 if (vma->vm_flags & VM_READ)
8719 if (vma->vm_flags & VM_WRITE)
8721 if (vma->vm_flags & VM_EXEC)
8724 if (vma->vm_flags & VM_MAYSHARE)
8727 flags = MAP_PRIVATE;
8729 if (vma->vm_flags & VM_LOCKED)
8730 flags |= MAP_LOCKED;
8731 if (is_vm_hugetlb_page(vma))
8732 flags |= MAP_HUGETLB;
8735 struct inode *inode;
8738 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8744 * d_path() works from the end of the rb backwards, so we
8745 * need to add enough zero bytes after the string to handle
8746 * the 64bit alignment we do later.
8748 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8753 inode = file_inode(vma->vm_file);
8754 dev = inode->i_sb->s_dev;
8756 gen = inode->i_generation;
8762 if (vma->vm_ops && vma->vm_ops->name)
8763 name = (char *) vma->vm_ops->name(vma);
8765 name = (char *)arch_vma_name(vma);
8767 if (vma_is_initial_heap(vma))
8769 else if (vma_is_initial_stack(vma))
8777 strscpy(tmp, name, sizeof(tmp));
8781 * Since our buffer works in 8 byte units we need to align our string
8782 * size to a multiple of 8. However, we must guarantee the tail end is
8783 * zero'd out to avoid leaking random bits to userspace.
8785 size = strlen(name)+1;
8786 while (!IS_ALIGNED(size, sizeof(u64)))
8787 name[size++] = '\0';
8789 mmap_event->file_name = name;
8790 mmap_event->file_size = size;
8791 mmap_event->maj = maj;
8792 mmap_event->min = min;
8793 mmap_event->ino = ino;
8794 mmap_event->ino_generation = gen;
8795 mmap_event->prot = prot;
8796 mmap_event->flags = flags;
8798 if (!(vma->vm_flags & VM_EXEC))
8799 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8801 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8803 if (atomic_read(&nr_build_id_events))
8804 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8806 perf_iterate_sb(perf_event_mmap_output,
8814 * Check whether inode and address range match filter criteria.
8816 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8817 struct file *file, unsigned long offset,
8820 /* d_inode(NULL) won't be equal to any mapped user-space file */
8821 if (!filter->path.dentry)
8824 if (d_inode(filter->path.dentry) != file_inode(file))
8827 if (filter->offset > offset + size)
8830 if (filter->offset + filter->size < offset)
8836 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8837 struct vm_area_struct *vma,
8838 struct perf_addr_filter_range *fr)
8840 unsigned long vma_size = vma->vm_end - vma->vm_start;
8841 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8842 struct file *file = vma->vm_file;
8844 if (!perf_addr_filter_match(filter, file, off, vma_size))
8847 if (filter->offset < off) {
8848 fr->start = vma->vm_start;
8849 fr->size = min(vma_size, filter->size - (off - filter->offset));
8851 fr->start = vma->vm_start + filter->offset - off;
8852 fr->size = min(vma->vm_end - fr->start, filter->size);
8858 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8860 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8861 struct vm_area_struct *vma = data;
8862 struct perf_addr_filter *filter;
8863 unsigned int restart = 0, count = 0;
8864 unsigned long flags;
8866 if (!has_addr_filter(event))
8872 raw_spin_lock_irqsave(&ifh->lock, flags);
8873 list_for_each_entry(filter, &ifh->list, entry) {
8874 if (perf_addr_filter_vma_adjust(filter, vma,
8875 &event->addr_filter_ranges[count]))
8882 event->addr_filters_gen++;
8883 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8886 perf_event_stop(event, 1);
8890 * Adjust all task's events' filters to the new vma
8892 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8894 struct perf_event_context *ctx;
8897 * Data tracing isn't supported yet and as such there is no need
8898 * to keep track of anything that isn't related to executable code:
8900 if (!(vma->vm_flags & VM_EXEC))
8904 ctx = rcu_dereference(current->perf_event_ctxp);
8906 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8910 void perf_event_mmap(struct vm_area_struct *vma)
8912 struct perf_mmap_event mmap_event;
8914 if (!atomic_read(&nr_mmap_events))
8917 mmap_event = (struct perf_mmap_event){
8923 .type = PERF_RECORD_MMAP,
8924 .misc = PERF_RECORD_MISC_USER,
8929 .start = vma->vm_start,
8930 .len = vma->vm_end - vma->vm_start,
8931 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8933 /* .maj (attr_mmap2 only) */
8934 /* .min (attr_mmap2 only) */
8935 /* .ino (attr_mmap2 only) */
8936 /* .ino_generation (attr_mmap2 only) */
8937 /* .prot (attr_mmap2 only) */
8938 /* .flags (attr_mmap2 only) */
8941 perf_addr_filters_adjust(vma);
8942 perf_event_mmap_event(&mmap_event);
8945 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8946 unsigned long size, u64 flags)
8948 struct perf_output_handle handle;
8949 struct perf_sample_data sample;
8950 struct perf_aux_event {
8951 struct perf_event_header header;
8957 .type = PERF_RECORD_AUX,
8959 .size = sizeof(rec),
8967 perf_event_header__init_id(&rec.header, &sample, event);
8968 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8973 perf_output_put(&handle, rec);
8974 perf_event__output_id_sample(event, &handle, &sample);
8976 perf_output_end(&handle);
8980 * Lost/dropped samples logging
8982 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8984 struct perf_output_handle handle;
8985 struct perf_sample_data sample;
8989 struct perf_event_header header;
8991 } lost_samples_event = {
8993 .type = PERF_RECORD_LOST_SAMPLES,
8995 .size = sizeof(lost_samples_event),
9000 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
9002 ret = perf_output_begin(&handle, &sample, event,
9003 lost_samples_event.header.size);
9007 perf_output_put(&handle, lost_samples_event);
9008 perf_event__output_id_sample(event, &handle, &sample);
9009 perf_output_end(&handle);
9013 * context_switch tracking
9016 struct perf_switch_event {
9017 struct task_struct *task;
9018 struct task_struct *next_prev;
9021 struct perf_event_header header;
9027 static int perf_event_switch_match(struct perf_event *event)
9029 return event->attr.context_switch;
9032 static void perf_event_switch_output(struct perf_event *event, void *data)
9034 struct perf_switch_event *se = data;
9035 struct perf_output_handle handle;
9036 struct perf_sample_data sample;
9039 if (!perf_event_switch_match(event))
9042 /* Only CPU-wide events are allowed to see next/prev pid/tid */
9043 if (event->ctx->task) {
9044 se->event_id.header.type = PERF_RECORD_SWITCH;
9045 se->event_id.header.size = sizeof(se->event_id.header);
9047 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
9048 se->event_id.header.size = sizeof(se->event_id);
9049 se->event_id.next_prev_pid =
9050 perf_event_pid(event, se->next_prev);
9051 se->event_id.next_prev_tid =
9052 perf_event_tid(event, se->next_prev);
9055 perf_event_header__init_id(&se->event_id.header, &sample, event);
9057 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
9061 if (event->ctx->task)
9062 perf_output_put(&handle, se->event_id.header);
9064 perf_output_put(&handle, se->event_id);
9066 perf_event__output_id_sample(event, &handle, &sample);
9068 perf_output_end(&handle);
9071 static void perf_event_switch(struct task_struct *task,
9072 struct task_struct *next_prev, bool sched_in)
9074 struct perf_switch_event switch_event;
9076 /* N.B. caller checks nr_switch_events != 0 */
9078 switch_event = (struct perf_switch_event){
9080 .next_prev = next_prev,
9084 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
9087 /* .next_prev_pid */
9088 /* .next_prev_tid */
9092 if (!sched_in && task->on_rq) {
9093 switch_event.event_id.header.misc |=
9094 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
9097 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
9101 * IRQ throttle logging
9104 static void perf_log_throttle(struct perf_event *event, int enable)
9106 struct perf_output_handle handle;
9107 struct perf_sample_data sample;
9111 struct perf_event_header header;
9115 } throttle_event = {
9117 .type = PERF_RECORD_THROTTLE,
9119 .size = sizeof(throttle_event),
9121 .time = perf_event_clock(event),
9122 .id = primary_event_id(event),
9123 .stream_id = event->id,
9127 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
9129 perf_event_header__init_id(&throttle_event.header, &sample, event);
9131 ret = perf_output_begin(&handle, &sample, event,
9132 throttle_event.header.size);
9136 perf_output_put(&handle, throttle_event);
9137 perf_event__output_id_sample(event, &handle, &sample);
9138 perf_output_end(&handle);
9142 * ksymbol register/unregister tracking
9145 struct perf_ksymbol_event {
9149 struct perf_event_header header;
9157 static int perf_event_ksymbol_match(struct perf_event *event)
9159 return event->attr.ksymbol;
9162 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
9164 struct perf_ksymbol_event *ksymbol_event = data;
9165 struct perf_output_handle handle;
9166 struct perf_sample_data sample;
9169 if (!perf_event_ksymbol_match(event))
9172 perf_event_header__init_id(&ksymbol_event->event_id.header,
9174 ret = perf_output_begin(&handle, &sample, event,
9175 ksymbol_event->event_id.header.size);
9179 perf_output_put(&handle, ksymbol_event->event_id);
9180 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
9181 perf_event__output_id_sample(event, &handle, &sample);
9183 perf_output_end(&handle);
9186 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
9189 struct perf_ksymbol_event ksymbol_event;
9190 char name[KSYM_NAME_LEN];
9194 if (!atomic_read(&nr_ksymbol_events))
9197 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
9198 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
9201 strscpy(name, sym, KSYM_NAME_LEN);
9202 name_len = strlen(name) + 1;
9203 while (!IS_ALIGNED(name_len, sizeof(u64)))
9204 name[name_len++] = '\0';
9205 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
9208 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
9210 ksymbol_event = (struct perf_ksymbol_event){
9212 .name_len = name_len,
9215 .type = PERF_RECORD_KSYMBOL,
9216 .size = sizeof(ksymbol_event.event_id) +
9221 .ksym_type = ksym_type,
9226 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
9229 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
9233 * bpf program load/unload tracking
9236 struct perf_bpf_event {
9237 struct bpf_prog *prog;
9239 struct perf_event_header header;
9243 u8 tag[BPF_TAG_SIZE];
9247 static int perf_event_bpf_match(struct perf_event *event)
9249 return event->attr.bpf_event;
9252 static void perf_event_bpf_output(struct perf_event *event, void *data)
9254 struct perf_bpf_event *bpf_event = data;
9255 struct perf_output_handle handle;
9256 struct perf_sample_data sample;
9259 if (!perf_event_bpf_match(event))
9262 perf_event_header__init_id(&bpf_event->event_id.header,
9264 ret = perf_output_begin(&handle, &sample, event,
9265 bpf_event->event_id.header.size);
9269 perf_output_put(&handle, bpf_event->event_id);
9270 perf_event__output_id_sample(event, &handle, &sample);
9272 perf_output_end(&handle);
9275 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
9276 enum perf_bpf_event_type type)
9278 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
9281 if (prog->aux->func_cnt == 0) {
9282 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
9283 (u64)(unsigned long)prog->bpf_func,
9284 prog->jited_len, unregister,
9285 prog->aux->ksym.name);
9287 for (i = 0; i < prog->aux->func_cnt; i++) {
9288 struct bpf_prog *subprog = prog->aux->func[i];
9291 PERF_RECORD_KSYMBOL_TYPE_BPF,
9292 (u64)(unsigned long)subprog->bpf_func,
9293 subprog->jited_len, unregister,
9294 subprog->aux->ksym.name);
9299 void perf_event_bpf_event(struct bpf_prog *prog,
9300 enum perf_bpf_event_type type,
9303 struct perf_bpf_event bpf_event;
9306 case PERF_BPF_EVENT_PROG_LOAD:
9307 case PERF_BPF_EVENT_PROG_UNLOAD:
9308 if (atomic_read(&nr_ksymbol_events))
9309 perf_event_bpf_emit_ksymbols(prog, type);
9315 if (!atomic_read(&nr_bpf_events))
9318 bpf_event = (struct perf_bpf_event){
9322 .type = PERF_RECORD_BPF_EVENT,
9323 .size = sizeof(bpf_event.event_id),
9327 .id = prog->aux->id,
9331 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9333 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9334 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9337 struct perf_text_poke_event {
9338 const void *old_bytes;
9339 const void *new_bytes;
9345 struct perf_event_header header;
9351 static int perf_event_text_poke_match(struct perf_event *event)
9353 return event->attr.text_poke;
9356 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9358 struct perf_text_poke_event *text_poke_event = data;
9359 struct perf_output_handle handle;
9360 struct perf_sample_data sample;
9364 if (!perf_event_text_poke_match(event))
9367 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9369 ret = perf_output_begin(&handle, &sample, event,
9370 text_poke_event->event_id.header.size);
9374 perf_output_put(&handle, text_poke_event->event_id);
9375 perf_output_put(&handle, text_poke_event->old_len);
9376 perf_output_put(&handle, text_poke_event->new_len);
9378 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9379 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9381 if (text_poke_event->pad)
9382 __output_copy(&handle, &padding, text_poke_event->pad);
9384 perf_event__output_id_sample(event, &handle, &sample);
9386 perf_output_end(&handle);
9389 void perf_event_text_poke(const void *addr, const void *old_bytes,
9390 size_t old_len, const void *new_bytes, size_t new_len)
9392 struct perf_text_poke_event text_poke_event;
9395 if (!atomic_read(&nr_text_poke_events))
9398 tot = sizeof(text_poke_event.old_len) + old_len;
9399 tot += sizeof(text_poke_event.new_len) + new_len;
9400 pad = ALIGN(tot, sizeof(u64)) - tot;
9402 text_poke_event = (struct perf_text_poke_event){
9403 .old_bytes = old_bytes,
9404 .new_bytes = new_bytes,
9410 .type = PERF_RECORD_TEXT_POKE,
9411 .misc = PERF_RECORD_MISC_KERNEL,
9412 .size = sizeof(text_poke_event.event_id) + tot + pad,
9414 .addr = (unsigned long)addr,
9418 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9421 void perf_event_itrace_started(struct perf_event *event)
9423 event->attach_state |= PERF_ATTACH_ITRACE;
9426 static void perf_log_itrace_start(struct perf_event *event)
9428 struct perf_output_handle handle;
9429 struct perf_sample_data sample;
9430 struct perf_aux_event {
9431 struct perf_event_header header;
9438 event = event->parent;
9440 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9441 event->attach_state & PERF_ATTACH_ITRACE)
9444 rec.header.type = PERF_RECORD_ITRACE_START;
9445 rec.header.misc = 0;
9446 rec.header.size = sizeof(rec);
9447 rec.pid = perf_event_pid(event, current);
9448 rec.tid = perf_event_tid(event, current);
9450 perf_event_header__init_id(&rec.header, &sample, event);
9451 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9456 perf_output_put(&handle, rec);
9457 perf_event__output_id_sample(event, &handle, &sample);
9459 perf_output_end(&handle);
9462 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9464 struct perf_output_handle handle;
9465 struct perf_sample_data sample;
9466 struct perf_aux_event {
9467 struct perf_event_header header;
9473 event = event->parent;
9475 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9476 rec.header.misc = 0;
9477 rec.header.size = sizeof(rec);
9480 perf_event_header__init_id(&rec.header, &sample, event);
9481 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9486 perf_output_put(&handle, rec);
9487 perf_event__output_id_sample(event, &handle, &sample);
9489 perf_output_end(&handle);
9491 EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
9494 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9496 struct hw_perf_event *hwc = &event->hw;
9500 seq = __this_cpu_read(perf_throttled_seq);
9501 if (seq != hwc->interrupts_seq) {
9502 hwc->interrupts_seq = seq;
9503 hwc->interrupts = 1;
9506 if (unlikely(throttle &&
9507 hwc->interrupts > max_samples_per_tick)) {
9508 __this_cpu_inc(perf_throttled_count);
9509 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9510 hwc->interrupts = MAX_INTERRUPTS;
9511 perf_log_throttle(event, 0);
9516 if (event->attr.freq) {
9517 u64 now = perf_clock();
9518 s64 delta = now - hwc->freq_time_stamp;
9520 hwc->freq_time_stamp = now;
9522 if (delta > 0 && delta < 2*TICK_NSEC)
9523 perf_adjust_period(event, delta, hwc->last_period, true);
9529 int perf_event_account_interrupt(struct perf_event *event)
9531 return __perf_event_account_interrupt(event, 1);
9534 static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
9537 * Due to interrupt latency (AKA "skid"), we may enter the
9538 * kernel before taking an overflow, even if the PMU is only
9539 * counting user events.
9541 if (event->attr.exclude_kernel && !user_mode(regs))
9548 * Generic event overflow handling, sampling.
9551 static int __perf_event_overflow(struct perf_event *event,
9552 int throttle, struct perf_sample_data *data,
9553 struct pt_regs *regs)
9555 int events = atomic_read(&event->event_limit);
9559 * Non-sampling counters might still use the PMI to fold short
9560 * hardware counters, ignore those.
9562 if (unlikely(!is_sampling_event(event)))
9565 ret = __perf_event_account_interrupt(event, throttle);
9568 * XXX event_limit might not quite work as expected on inherited
9572 event->pending_kill = POLL_IN;
9573 if (events && atomic_dec_and_test(&event->event_limit)) {
9575 event->pending_kill = POLL_HUP;
9576 perf_event_disable_inatomic(event);
9579 if (event->attr.sigtrap) {
9581 * The desired behaviour of sigtrap vs invalid samples is a bit
9582 * tricky; on the one hand, one should not loose the SIGTRAP if
9583 * it is the first event, on the other hand, we should also not
9584 * trigger the WARN or override the data address.
9586 bool valid_sample = sample_is_allowed(event, regs);
9587 unsigned int pending_id = 1;
9590 pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1;
9591 if (!event->pending_sigtrap) {
9592 event->pending_sigtrap = pending_id;
9593 local_inc(&event->ctx->nr_pending);
9594 } else if (event->attr.exclude_kernel && valid_sample) {
9596 * Should not be able to return to user space without
9597 * consuming pending_sigtrap; with exceptions:
9599 * 1. Where !exclude_kernel, events can overflow again
9600 * in the kernel without returning to user space.
9602 * 2. Events that can overflow again before the IRQ-
9603 * work without user space progress (e.g. hrtimer).
9604 * To approximate progress (with false negatives),
9605 * check 32-bit hash of the current IP.
9607 WARN_ON_ONCE(event->pending_sigtrap != pending_id);
9610 event->pending_addr = 0;
9611 if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
9612 event->pending_addr = data->addr;
9613 irq_work_queue(&event->pending_irq);
9616 READ_ONCE(event->overflow_handler)(event, data, regs);
9618 if (*perf_event_fasync(event) && event->pending_kill) {
9619 event->pending_wakeup = 1;
9620 irq_work_queue(&event->pending_irq);
9626 int perf_event_overflow(struct perf_event *event,
9627 struct perf_sample_data *data,
9628 struct pt_regs *regs)
9630 return __perf_event_overflow(event, 1, data, regs);
9634 * Generic software event infrastructure
9637 struct swevent_htable {
9638 struct swevent_hlist *swevent_hlist;
9639 struct mutex hlist_mutex;
9642 /* Recursion avoidance in each contexts */
9643 int recursion[PERF_NR_CONTEXTS];
9646 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9649 * We directly increment event->count and keep a second value in
9650 * event->hw.period_left to count intervals. This period event
9651 * is kept in the range [-sample_period, 0] so that we can use the
9655 u64 perf_swevent_set_period(struct perf_event *event)
9657 struct hw_perf_event *hwc = &event->hw;
9658 u64 period = hwc->last_period;
9662 hwc->last_period = hwc->sample_period;
9664 old = local64_read(&hwc->period_left);
9670 nr = div64_u64(period + val, period);
9671 offset = nr * period;
9673 } while (!local64_try_cmpxchg(&hwc->period_left, &old, val));
9678 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9679 struct perf_sample_data *data,
9680 struct pt_regs *regs)
9682 struct hw_perf_event *hwc = &event->hw;
9686 overflow = perf_swevent_set_period(event);
9688 if (hwc->interrupts == MAX_INTERRUPTS)
9691 for (; overflow; overflow--) {
9692 if (__perf_event_overflow(event, throttle,
9695 * We inhibit the overflow from happening when
9696 * hwc->interrupts == MAX_INTERRUPTS.
9704 static void perf_swevent_event(struct perf_event *event, u64 nr,
9705 struct perf_sample_data *data,
9706 struct pt_regs *regs)
9708 struct hw_perf_event *hwc = &event->hw;
9710 local64_add(nr, &event->count);
9715 if (!is_sampling_event(event))
9718 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9720 return perf_swevent_overflow(event, 1, data, regs);
9722 data->period = event->hw.last_period;
9724 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9725 return perf_swevent_overflow(event, 1, data, regs);
9727 if (local64_add_negative(nr, &hwc->period_left))
9730 perf_swevent_overflow(event, 0, data, regs);
9733 static int perf_exclude_event(struct perf_event *event,
9734 struct pt_regs *regs)
9736 if (event->hw.state & PERF_HES_STOPPED)
9740 if (event->attr.exclude_user && user_mode(regs))
9743 if (event->attr.exclude_kernel && !user_mode(regs))
9750 static int perf_swevent_match(struct perf_event *event,
9751 enum perf_type_id type,
9753 struct perf_sample_data *data,
9754 struct pt_regs *regs)
9756 if (event->attr.type != type)
9759 if (event->attr.config != event_id)
9762 if (perf_exclude_event(event, regs))
9768 static inline u64 swevent_hash(u64 type, u32 event_id)
9770 u64 val = event_id | (type << 32);
9772 return hash_64(val, SWEVENT_HLIST_BITS);
9775 static inline struct hlist_head *
9776 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9778 u64 hash = swevent_hash(type, event_id);
9780 return &hlist->heads[hash];
9783 /* For the read side: events when they trigger */
9784 static inline struct hlist_head *
9785 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9787 struct swevent_hlist *hlist;
9789 hlist = rcu_dereference(swhash->swevent_hlist);
9793 return __find_swevent_head(hlist, type, event_id);
9796 /* For the event head insertion and removal in the hlist */
9797 static inline struct hlist_head *
9798 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9800 struct swevent_hlist *hlist;
9801 u32 event_id = event->attr.config;
9802 u64 type = event->attr.type;
9805 * Event scheduling is always serialized against hlist allocation
9806 * and release. Which makes the protected version suitable here.
9807 * The context lock guarantees that.
9809 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9810 lockdep_is_held(&event->ctx->lock));
9814 return __find_swevent_head(hlist, type, event_id);
9817 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9819 struct perf_sample_data *data,
9820 struct pt_regs *regs)
9822 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9823 struct perf_event *event;
9824 struct hlist_head *head;
9827 head = find_swevent_head_rcu(swhash, type, event_id);
9831 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9832 if (perf_swevent_match(event, type, event_id, data, regs))
9833 perf_swevent_event(event, nr, data, regs);
9839 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9841 int perf_swevent_get_recursion_context(void)
9843 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9845 return get_recursion_context(swhash->recursion);
9847 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9849 void perf_swevent_put_recursion_context(int rctx)
9851 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9853 put_recursion_context(swhash->recursion, rctx);
9856 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9858 struct perf_sample_data data;
9860 if (WARN_ON_ONCE(!regs))
9863 perf_sample_data_init(&data, addr, 0);
9864 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9867 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9871 preempt_disable_notrace();
9872 rctx = perf_swevent_get_recursion_context();
9873 if (unlikely(rctx < 0))
9876 ___perf_sw_event(event_id, nr, regs, addr);
9878 perf_swevent_put_recursion_context(rctx);
9880 preempt_enable_notrace();
9883 static void perf_swevent_read(struct perf_event *event)
9887 static int perf_swevent_add(struct perf_event *event, int flags)
9889 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9890 struct hw_perf_event *hwc = &event->hw;
9891 struct hlist_head *head;
9893 if (is_sampling_event(event)) {
9894 hwc->last_period = hwc->sample_period;
9895 perf_swevent_set_period(event);
9898 hwc->state = !(flags & PERF_EF_START);
9900 head = find_swevent_head(swhash, event);
9901 if (WARN_ON_ONCE(!head))
9904 hlist_add_head_rcu(&event->hlist_entry, head);
9905 perf_event_update_userpage(event);
9910 static void perf_swevent_del(struct perf_event *event, int flags)
9912 hlist_del_rcu(&event->hlist_entry);
9915 static void perf_swevent_start(struct perf_event *event, int flags)
9917 event->hw.state = 0;
9920 static void perf_swevent_stop(struct perf_event *event, int flags)
9922 event->hw.state = PERF_HES_STOPPED;
9925 /* Deref the hlist from the update side */
9926 static inline struct swevent_hlist *
9927 swevent_hlist_deref(struct swevent_htable *swhash)
9929 return rcu_dereference_protected(swhash->swevent_hlist,
9930 lockdep_is_held(&swhash->hlist_mutex));
9933 static void swevent_hlist_release(struct swevent_htable *swhash)
9935 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9940 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9941 kfree_rcu(hlist, rcu_head);
9944 static void swevent_hlist_put_cpu(int cpu)
9946 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9948 mutex_lock(&swhash->hlist_mutex);
9950 if (!--swhash->hlist_refcount)
9951 swevent_hlist_release(swhash);
9953 mutex_unlock(&swhash->hlist_mutex);
9956 static void swevent_hlist_put(void)
9960 for_each_possible_cpu(cpu)
9961 swevent_hlist_put_cpu(cpu);
9964 static int swevent_hlist_get_cpu(int cpu)
9966 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9969 mutex_lock(&swhash->hlist_mutex);
9970 if (!swevent_hlist_deref(swhash) &&
9971 cpumask_test_cpu(cpu, perf_online_mask)) {
9972 struct swevent_hlist *hlist;
9974 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9979 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9981 swhash->hlist_refcount++;
9983 mutex_unlock(&swhash->hlist_mutex);
9988 static int swevent_hlist_get(void)
9990 int err, cpu, failed_cpu;
9992 mutex_lock(&pmus_lock);
9993 for_each_possible_cpu(cpu) {
9994 err = swevent_hlist_get_cpu(cpu);
10000 mutex_unlock(&pmus_lock);
10003 for_each_possible_cpu(cpu) {
10004 if (cpu == failed_cpu)
10006 swevent_hlist_put_cpu(cpu);
10008 mutex_unlock(&pmus_lock);
10012 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
10014 static void sw_perf_event_destroy(struct perf_event *event)
10016 u64 event_id = event->attr.config;
10018 WARN_ON(event->parent);
10020 static_key_slow_dec(&perf_swevent_enabled[event_id]);
10021 swevent_hlist_put();
10024 static struct pmu perf_cpu_clock; /* fwd declaration */
10025 static struct pmu perf_task_clock;
10027 static int perf_swevent_init(struct perf_event *event)
10029 u64 event_id = event->attr.config;
10031 if (event->attr.type != PERF_TYPE_SOFTWARE)
10035 * no branch sampling for software events
10037 if (has_branch_stack(event))
10038 return -EOPNOTSUPP;
10040 switch (event_id) {
10041 case PERF_COUNT_SW_CPU_CLOCK:
10042 event->attr.type = perf_cpu_clock.type;
10044 case PERF_COUNT_SW_TASK_CLOCK:
10045 event->attr.type = perf_task_clock.type;
10052 if (event_id >= PERF_COUNT_SW_MAX)
10055 if (!event->parent) {
10058 err = swevent_hlist_get();
10062 static_key_slow_inc(&perf_swevent_enabled[event_id]);
10063 event->destroy = sw_perf_event_destroy;
10069 static struct pmu perf_swevent = {
10070 .task_ctx_nr = perf_sw_context,
10072 .capabilities = PERF_PMU_CAP_NO_NMI,
10074 .event_init = perf_swevent_init,
10075 .add = perf_swevent_add,
10076 .del = perf_swevent_del,
10077 .start = perf_swevent_start,
10078 .stop = perf_swevent_stop,
10079 .read = perf_swevent_read,
10082 #ifdef CONFIG_EVENT_TRACING
10084 static void tp_perf_event_destroy(struct perf_event *event)
10086 perf_trace_destroy(event);
10089 static int perf_tp_event_init(struct perf_event *event)
10093 if (event->attr.type != PERF_TYPE_TRACEPOINT)
10097 * no branch sampling for tracepoint events
10099 if (has_branch_stack(event))
10100 return -EOPNOTSUPP;
10102 err = perf_trace_init(event);
10106 event->destroy = tp_perf_event_destroy;
10111 static struct pmu perf_tracepoint = {
10112 .task_ctx_nr = perf_sw_context,
10114 .event_init = perf_tp_event_init,
10115 .add = perf_trace_add,
10116 .del = perf_trace_del,
10117 .start = perf_swevent_start,
10118 .stop = perf_swevent_stop,
10119 .read = perf_swevent_read,
10122 static int perf_tp_filter_match(struct perf_event *event,
10123 struct perf_sample_data *data)
10125 void *record = data->raw->frag.data;
10127 /* only top level events have filters set */
10129 event = event->parent;
10131 if (likely(!event->filter) || filter_match_preds(event->filter, record))
10136 static int perf_tp_event_match(struct perf_event *event,
10137 struct perf_sample_data *data,
10138 struct pt_regs *regs)
10140 if (event->hw.state & PERF_HES_STOPPED)
10143 * If exclude_kernel, only trace user-space tracepoints (uprobes)
10145 if (event->attr.exclude_kernel && !user_mode(regs))
10148 if (!perf_tp_filter_match(event, data))
10154 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
10155 struct trace_event_call *call, u64 count,
10156 struct pt_regs *regs, struct hlist_head *head,
10157 struct task_struct *task)
10159 if (bpf_prog_array_valid(call)) {
10160 *(struct pt_regs **)raw_data = regs;
10161 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
10162 perf_swevent_put_recursion_context(rctx);
10166 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
10169 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
10171 static void __perf_tp_event_target_task(u64 count, void *record,
10172 struct pt_regs *regs,
10173 struct perf_sample_data *data,
10174 struct perf_event *event)
10176 struct trace_entry *entry = record;
10178 if (event->attr.config != entry->type)
10180 /* Cannot deliver synchronous signal to other task. */
10181 if (event->attr.sigtrap)
10183 if (perf_tp_event_match(event, data, regs))
10184 perf_swevent_event(event, count, data, regs);
10187 static void perf_tp_event_target_task(u64 count, void *record,
10188 struct pt_regs *regs,
10189 struct perf_sample_data *data,
10190 struct perf_event_context *ctx)
10192 unsigned int cpu = smp_processor_id();
10193 struct pmu *pmu = &perf_tracepoint;
10194 struct perf_event *event, *sibling;
10196 perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) {
10197 __perf_tp_event_target_task(count, record, regs, data, event);
10198 for_each_sibling_event(sibling, event)
10199 __perf_tp_event_target_task(count, record, regs, data, sibling);
10202 perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) {
10203 __perf_tp_event_target_task(count, record, regs, data, event);
10204 for_each_sibling_event(sibling, event)
10205 __perf_tp_event_target_task(count, record, regs, data, sibling);
10209 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
10210 struct pt_regs *regs, struct hlist_head *head, int rctx,
10211 struct task_struct *task)
10213 struct perf_sample_data data;
10214 struct perf_event *event;
10216 struct perf_raw_record raw = {
10218 .size = entry_size,
10223 perf_sample_data_init(&data, 0, 0);
10224 perf_sample_save_raw_data(&data, &raw);
10226 perf_trace_buf_update(record, event_type);
10228 hlist_for_each_entry_rcu(event, head, hlist_entry) {
10229 if (perf_tp_event_match(event, &data, regs)) {
10230 perf_swevent_event(event, count, &data, regs);
10233 * Here use the same on-stack perf_sample_data,
10234 * some members in data are event-specific and
10235 * need to be re-computed for different sweveents.
10236 * Re-initialize data->sample_flags safely to avoid
10237 * the problem that next event skips preparing data
10238 * because data->sample_flags is set.
10240 perf_sample_data_init(&data, 0, 0);
10241 perf_sample_save_raw_data(&data, &raw);
10246 * If we got specified a target task, also iterate its context and
10247 * deliver this event there too.
10249 if (task && task != current) {
10250 struct perf_event_context *ctx;
10253 ctx = rcu_dereference(task->perf_event_ctxp);
10257 raw_spin_lock(&ctx->lock);
10258 perf_tp_event_target_task(count, record, regs, &data, ctx);
10259 raw_spin_unlock(&ctx->lock);
10264 perf_swevent_put_recursion_context(rctx);
10266 EXPORT_SYMBOL_GPL(perf_tp_event);
10268 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
10270 * Flags in config, used by dynamic PMU kprobe and uprobe
10271 * The flags should match following PMU_FORMAT_ATTR().
10273 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
10274 * if not set, create kprobe/uprobe
10276 * The following values specify a reference counter (or semaphore in the
10277 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
10278 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
10280 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
10281 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
10283 enum perf_probe_config {
10284 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
10285 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
10286 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
10289 PMU_FORMAT_ATTR(retprobe, "config:0");
10292 #ifdef CONFIG_KPROBE_EVENTS
10293 static struct attribute *kprobe_attrs[] = {
10294 &format_attr_retprobe.attr,
10298 static struct attribute_group kprobe_format_group = {
10300 .attrs = kprobe_attrs,
10303 static const struct attribute_group *kprobe_attr_groups[] = {
10304 &kprobe_format_group,
10308 static int perf_kprobe_event_init(struct perf_event *event);
10309 static struct pmu perf_kprobe = {
10310 .task_ctx_nr = perf_sw_context,
10311 .event_init = perf_kprobe_event_init,
10312 .add = perf_trace_add,
10313 .del = perf_trace_del,
10314 .start = perf_swevent_start,
10315 .stop = perf_swevent_stop,
10316 .read = perf_swevent_read,
10317 .attr_groups = kprobe_attr_groups,
10320 static int perf_kprobe_event_init(struct perf_event *event)
10325 if (event->attr.type != perf_kprobe.type)
10328 if (!perfmon_capable())
10332 * no branch sampling for probe events
10334 if (has_branch_stack(event))
10335 return -EOPNOTSUPP;
10337 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10338 err = perf_kprobe_init(event, is_retprobe);
10342 event->destroy = perf_kprobe_destroy;
10346 #endif /* CONFIG_KPROBE_EVENTS */
10348 #ifdef CONFIG_UPROBE_EVENTS
10349 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
10351 static struct attribute *uprobe_attrs[] = {
10352 &format_attr_retprobe.attr,
10353 &format_attr_ref_ctr_offset.attr,
10357 static struct attribute_group uprobe_format_group = {
10359 .attrs = uprobe_attrs,
10362 static const struct attribute_group *uprobe_attr_groups[] = {
10363 &uprobe_format_group,
10367 static int perf_uprobe_event_init(struct perf_event *event);
10368 static struct pmu perf_uprobe = {
10369 .task_ctx_nr = perf_sw_context,
10370 .event_init = perf_uprobe_event_init,
10371 .add = perf_trace_add,
10372 .del = perf_trace_del,
10373 .start = perf_swevent_start,
10374 .stop = perf_swevent_stop,
10375 .read = perf_swevent_read,
10376 .attr_groups = uprobe_attr_groups,
10379 static int perf_uprobe_event_init(struct perf_event *event)
10382 unsigned long ref_ctr_offset;
10385 if (event->attr.type != perf_uprobe.type)
10388 if (!perfmon_capable())
10392 * no branch sampling for probe events
10394 if (has_branch_stack(event))
10395 return -EOPNOTSUPP;
10397 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10398 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10399 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10403 event->destroy = perf_uprobe_destroy;
10407 #endif /* CONFIG_UPROBE_EVENTS */
10409 static inline void perf_tp_register(void)
10411 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10412 #ifdef CONFIG_KPROBE_EVENTS
10413 perf_pmu_register(&perf_kprobe, "kprobe", -1);
10415 #ifdef CONFIG_UPROBE_EVENTS
10416 perf_pmu_register(&perf_uprobe, "uprobe", -1);
10420 static void perf_event_free_filter(struct perf_event *event)
10422 ftrace_profile_free_filter(event);
10425 #ifdef CONFIG_BPF_SYSCALL
10426 static void bpf_overflow_handler(struct perf_event *event,
10427 struct perf_sample_data *data,
10428 struct pt_regs *regs)
10430 struct bpf_perf_event_data_kern ctx = {
10434 struct bpf_prog *prog;
10437 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10438 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10441 prog = READ_ONCE(event->prog);
10443 perf_prepare_sample(data, event, regs);
10444 ret = bpf_prog_run(prog, &ctx);
10448 __this_cpu_dec(bpf_prog_active);
10452 event->orig_overflow_handler(event, data, regs);
10455 static int perf_event_set_bpf_handler(struct perf_event *event,
10456 struct bpf_prog *prog,
10459 if (event->overflow_handler_context)
10460 /* hw breakpoint or kernel counter */
10466 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10469 if (event->attr.precise_ip &&
10470 prog->call_get_stack &&
10471 (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
10472 event->attr.exclude_callchain_kernel ||
10473 event->attr.exclude_callchain_user)) {
10475 * On perf_event with precise_ip, calling bpf_get_stack()
10476 * may trigger unwinder warnings and occasional crashes.
10477 * bpf_get_[stack|stackid] works around this issue by using
10478 * callchain attached to perf_sample_data. If the
10479 * perf_event does not full (kernel and user) callchain
10480 * attached to perf_sample_data, do not allow attaching BPF
10481 * program that calls bpf_get_[stack|stackid].
10486 event->prog = prog;
10487 event->bpf_cookie = bpf_cookie;
10488 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10489 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10493 static void perf_event_free_bpf_handler(struct perf_event *event)
10495 struct bpf_prog *prog = event->prog;
10500 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10501 event->prog = NULL;
10502 bpf_prog_put(prog);
10505 static int perf_event_set_bpf_handler(struct perf_event *event,
10506 struct bpf_prog *prog,
10509 return -EOPNOTSUPP;
10511 static void perf_event_free_bpf_handler(struct perf_event *event)
10517 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10518 * with perf_event_open()
10520 static inline bool perf_event_is_tracing(struct perf_event *event)
10522 if (event->pmu == &perf_tracepoint)
10524 #ifdef CONFIG_KPROBE_EVENTS
10525 if (event->pmu == &perf_kprobe)
10528 #ifdef CONFIG_UPROBE_EVENTS
10529 if (event->pmu == &perf_uprobe)
10535 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10538 bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp;
10540 if (!perf_event_is_tracing(event))
10541 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10543 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE;
10544 is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE;
10545 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10546 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10547 if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp)
10548 /* bpf programs can only be attached to u/kprobe or tracepoint */
10551 if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) ||
10552 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10553 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10556 if (prog->type == BPF_PROG_TYPE_KPROBE && prog->sleepable && !is_uprobe)
10557 /* only uprobe programs are allowed to be sleepable */
10560 /* Kprobe override only works for kprobes, not uprobes. */
10561 if (prog->kprobe_override && !is_kprobe)
10564 if (is_tracepoint || is_syscall_tp) {
10565 int off = trace_event_get_offsets(event->tp_event);
10567 if (prog->aux->max_ctx_offset > off)
10571 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10574 void perf_event_free_bpf_prog(struct perf_event *event)
10576 if (!perf_event_is_tracing(event)) {
10577 perf_event_free_bpf_handler(event);
10580 perf_event_detach_bpf_prog(event);
10585 static inline void perf_tp_register(void)
10589 static void perf_event_free_filter(struct perf_event *event)
10593 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10599 void perf_event_free_bpf_prog(struct perf_event *event)
10602 #endif /* CONFIG_EVENT_TRACING */
10604 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10605 void perf_bp_event(struct perf_event *bp, void *data)
10607 struct perf_sample_data sample;
10608 struct pt_regs *regs = data;
10610 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10612 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10613 perf_swevent_event(bp, 1, &sample, regs);
10618 * Allocate a new address filter
10620 static struct perf_addr_filter *
10621 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10623 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10624 struct perf_addr_filter *filter;
10626 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10630 INIT_LIST_HEAD(&filter->entry);
10631 list_add_tail(&filter->entry, filters);
10636 static void free_filters_list(struct list_head *filters)
10638 struct perf_addr_filter *filter, *iter;
10640 list_for_each_entry_safe(filter, iter, filters, entry) {
10641 path_put(&filter->path);
10642 list_del(&filter->entry);
10648 * Free existing address filters and optionally install new ones
10650 static void perf_addr_filters_splice(struct perf_event *event,
10651 struct list_head *head)
10653 unsigned long flags;
10656 if (!has_addr_filter(event))
10659 /* don't bother with children, they don't have their own filters */
10663 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10665 list_splice_init(&event->addr_filters.list, &list);
10667 list_splice(head, &event->addr_filters.list);
10669 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10671 free_filters_list(&list);
10675 * Scan through mm's vmas and see if one of them matches the
10676 * @filter; if so, adjust filter's address range.
10677 * Called with mm::mmap_lock down for reading.
10679 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10680 struct mm_struct *mm,
10681 struct perf_addr_filter_range *fr)
10683 struct vm_area_struct *vma;
10684 VMA_ITERATOR(vmi, mm, 0);
10686 for_each_vma(vmi, vma) {
10690 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10696 * Update event's address range filters based on the
10697 * task's existing mappings, if any.
10699 static void perf_event_addr_filters_apply(struct perf_event *event)
10701 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10702 struct task_struct *task = READ_ONCE(event->ctx->task);
10703 struct perf_addr_filter *filter;
10704 struct mm_struct *mm = NULL;
10705 unsigned int count = 0;
10706 unsigned long flags;
10709 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10710 * will stop on the parent's child_mutex that our caller is also holding
10712 if (task == TASK_TOMBSTONE)
10715 if (ifh->nr_file_filters) {
10716 mm = get_task_mm(task);
10720 mmap_read_lock(mm);
10723 raw_spin_lock_irqsave(&ifh->lock, flags);
10724 list_for_each_entry(filter, &ifh->list, entry) {
10725 if (filter->path.dentry) {
10727 * Adjust base offset if the filter is associated to a
10728 * binary that needs to be mapped:
10730 event->addr_filter_ranges[count].start = 0;
10731 event->addr_filter_ranges[count].size = 0;
10733 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10735 event->addr_filter_ranges[count].start = filter->offset;
10736 event->addr_filter_ranges[count].size = filter->size;
10742 event->addr_filters_gen++;
10743 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10745 if (ifh->nr_file_filters) {
10746 mmap_read_unlock(mm);
10752 perf_event_stop(event, 1);
10756 * Address range filtering: limiting the data to certain
10757 * instruction address ranges. Filters are ioctl()ed to us from
10758 * userspace as ascii strings.
10760 * Filter string format:
10762 * ACTION RANGE_SPEC
10763 * where ACTION is one of the
10764 * * "filter": limit the trace to this region
10765 * * "start": start tracing from this address
10766 * * "stop": stop tracing at this address/region;
10768 * * for kernel addresses: <start address>[/<size>]
10769 * * for object files: <start address>[/<size>]@</path/to/object/file>
10771 * if <size> is not specified or is zero, the range is treated as a single
10772 * address; not valid for ACTION=="filter".
10786 IF_STATE_ACTION = 0,
10791 static const match_table_t if_tokens = {
10792 { IF_ACT_FILTER, "filter" },
10793 { IF_ACT_START, "start" },
10794 { IF_ACT_STOP, "stop" },
10795 { IF_SRC_FILE, "%u/%u@%s" },
10796 { IF_SRC_KERNEL, "%u/%u" },
10797 { IF_SRC_FILEADDR, "%u@%s" },
10798 { IF_SRC_KERNELADDR, "%u" },
10799 { IF_ACT_NONE, NULL },
10803 * Address filter string parser
10806 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10807 struct list_head *filters)
10809 struct perf_addr_filter *filter = NULL;
10810 char *start, *orig, *filename = NULL;
10811 substring_t args[MAX_OPT_ARGS];
10812 int state = IF_STATE_ACTION, token;
10813 unsigned int kernel = 0;
10816 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10820 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10821 static const enum perf_addr_filter_action_t actions[] = {
10822 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10823 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10824 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10831 /* filter definition begins */
10832 if (state == IF_STATE_ACTION) {
10833 filter = perf_addr_filter_new(event, filters);
10838 token = match_token(start, if_tokens, args);
10840 case IF_ACT_FILTER:
10843 if (state != IF_STATE_ACTION)
10846 filter->action = actions[token];
10847 state = IF_STATE_SOURCE;
10850 case IF_SRC_KERNELADDR:
10851 case IF_SRC_KERNEL:
10855 case IF_SRC_FILEADDR:
10857 if (state != IF_STATE_SOURCE)
10861 ret = kstrtoul(args[0].from, 0, &filter->offset);
10865 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10867 ret = kstrtoul(args[1].from, 0, &filter->size);
10872 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10873 int fpos = token == IF_SRC_FILE ? 2 : 1;
10876 filename = match_strdup(&args[fpos]);
10883 state = IF_STATE_END;
10891 * Filter definition is fully parsed, validate and install it.
10892 * Make sure that it doesn't contradict itself or the event's
10895 if (state == IF_STATE_END) {
10899 * ACTION "filter" must have a non-zero length region
10902 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10911 * For now, we only support file-based filters
10912 * in per-task events; doing so for CPU-wide
10913 * events requires additional context switching
10914 * trickery, since same object code will be
10915 * mapped at different virtual addresses in
10916 * different processes.
10919 if (!event->ctx->task)
10922 /* look up the path and grab its inode */
10923 ret = kern_path(filename, LOOKUP_FOLLOW,
10929 if (!filter->path.dentry ||
10930 !S_ISREG(d_inode(filter->path.dentry)
10934 event->addr_filters.nr_file_filters++;
10937 /* ready to consume more filters */
10940 state = IF_STATE_ACTION;
10946 if (state != IF_STATE_ACTION)
10956 free_filters_list(filters);
10963 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10965 LIST_HEAD(filters);
10969 * Since this is called in perf_ioctl() path, we're already holding
10972 lockdep_assert_held(&event->ctx->mutex);
10974 if (WARN_ON_ONCE(event->parent))
10977 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10979 goto fail_clear_files;
10981 ret = event->pmu->addr_filters_validate(&filters);
10983 goto fail_free_filters;
10985 /* remove existing filters, if any */
10986 perf_addr_filters_splice(event, &filters);
10988 /* install new filters */
10989 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10994 free_filters_list(&filters);
10997 event->addr_filters.nr_file_filters = 0;
11002 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
11007 filter_str = strndup_user(arg, PAGE_SIZE);
11008 if (IS_ERR(filter_str))
11009 return PTR_ERR(filter_str);
11011 #ifdef CONFIG_EVENT_TRACING
11012 if (perf_event_is_tracing(event)) {
11013 struct perf_event_context *ctx = event->ctx;
11016 * Beware, here be dragons!!
11018 * the tracepoint muck will deadlock against ctx->mutex, but
11019 * the tracepoint stuff does not actually need it. So
11020 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
11021 * already have a reference on ctx.
11023 * This can result in event getting moved to a different ctx,
11024 * but that does not affect the tracepoint state.
11026 mutex_unlock(&ctx->mutex);
11027 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
11028 mutex_lock(&ctx->mutex);
11031 if (has_addr_filter(event))
11032 ret = perf_event_set_addr_filter(event, filter_str);
11039 * hrtimer based swevent callback
11042 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
11044 enum hrtimer_restart ret = HRTIMER_RESTART;
11045 struct perf_sample_data data;
11046 struct pt_regs *regs;
11047 struct perf_event *event;
11050 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
11052 if (event->state != PERF_EVENT_STATE_ACTIVE)
11053 return HRTIMER_NORESTART;
11055 event->pmu->read(event);
11057 perf_sample_data_init(&data, 0, event->hw.last_period);
11058 regs = get_irq_regs();
11060 if (regs && !perf_exclude_event(event, regs)) {
11061 if (!(event->attr.exclude_idle && is_idle_task(current)))
11062 if (__perf_event_overflow(event, 1, &data, regs))
11063 ret = HRTIMER_NORESTART;
11066 period = max_t(u64, 10000, event->hw.sample_period);
11067 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
11072 static void perf_swevent_start_hrtimer(struct perf_event *event)
11074 struct hw_perf_event *hwc = &event->hw;
11077 if (!is_sampling_event(event))
11080 period = local64_read(&hwc->period_left);
11085 local64_set(&hwc->period_left, 0);
11087 period = max_t(u64, 10000, hwc->sample_period);
11089 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
11090 HRTIMER_MODE_REL_PINNED_HARD);
11093 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
11095 struct hw_perf_event *hwc = &event->hw;
11097 if (is_sampling_event(event)) {
11098 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
11099 local64_set(&hwc->period_left, ktime_to_ns(remaining));
11101 hrtimer_cancel(&hwc->hrtimer);
11105 static void perf_swevent_init_hrtimer(struct perf_event *event)
11107 struct hw_perf_event *hwc = &event->hw;
11109 if (!is_sampling_event(event))
11112 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
11113 hwc->hrtimer.function = perf_swevent_hrtimer;
11116 * Since hrtimers have a fixed rate, we can do a static freq->period
11117 * mapping and avoid the whole period adjust feedback stuff.
11119 if (event->attr.freq) {
11120 long freq = event->attr.sample_freq;
11122 event->attr.sample_period = NSEC_PER_SEC / freq;
11123 hwc->sample_period = event->attr.sample_period;
11124 local64_set(&hwc->period_left, hwc->sample_period);
11125 hwc->last_period = hwc->sample_period;
11126 event->attr.freq = 0;
11131 * Software event: cpu wall time clock
11134 static void cpu_clock_event_update(struct perf_event *event)
11139 now = local_clock();
11140 prev = local64_xchg(&event->hw.prev_count, now);
11141 local64_add(now - prev, &event->count);
11144 static void cpu_clock_event_start(struct perf_event *event, int flags)
11146 local64_set(&event->hw.prev_count, local_clock());
11147 perf_swevent_start_hrtimer(event);
11150 static void cpu_clock_event_stop(struct perf_event *event, int flags)
11152 perf_swevent_cancel_hrtimer(event);
11153 cpu_clock_event_update(event);
11156 static int cpu_clock_event_add(struct perf_event *event, int flags)
11158 if (flags & PERF_EF_START)
11159 cpu_clock_event_start(event, flags);
11160 perf_event_update_userpage(event);
11165 static void cpu_clock_event_del(struct perf_event *event, int flags)
11167 cpu_clock_event_stop(event, flags);
11170 static void cpu_clock_event_read(struct perf_event *event)
11172 cpu_clock_event_update(event);
11175 static int cpu_clock_event_init(struct perf_event *event)
11177 if (event->attr.type != perf_cpu_clock.type)
11180 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
11184 * no branch sampling for software events
11186 if (has_branch_stack(event))
11187 return -EOPNOTSUPP;
11189 perf_swevent_init_hrtimer(event);
11194 static struct pmu perf_cpu_clock = {
11195 .task_ctx_nr = perf_sw_context,
11197 .capabilities = PERF_PMU_CAP_NO_NMI,
11198 .dev = PMU_NULL_DEV,
11200 .event_init = cpu_clock_event_init,
11201 .add = cpu_clock_event_add,
11202 .del = cpu_clock_event_del,
11203 .start = cpu_clock_event_start,
11204 .stop = cpu_clock_event_stop,
11205 .read = cpu_clock_event_read,
11209 * Software event: task time clock
11212 static void task_clock_event_update(struct perf_event *event, u64 now)
11217 prev = local64_xchg(&event->hw.prev_count, now);
11218 delta = now - prev;
11219 local64_add(delta, &event->count);
11222 static void task_clock_event_start(struct perf_event *event, int flags)
11224 local64_set(&event->hw.prev_count, event->ctx->time);
11225 perf_swevent_start_hrtimer(event);
11228 static void task_clock_event_stop(struct perf_event *event, int flags)
11230 perf_swevent_cancel_hrtimer(event);
11231 task_clock_event_update(event, event->ctx->time);
11234 static int task_clock_event_add(struct perf_event *event, int flags)
11236 if (flags & PERF_EF_START)
11237 task_clock_event_start(event, flags);
11238 perf_event_update_userpage(event);
11243 static void task_clock_event_del(struct perf_event *event, int flags)
11245 task_clock_event_stop(event, PERF_EF_UPDATE);
11248 static void task_clock_event_read(struct perf_event *event)
11250 u64 now = perf_clock();
11251 u64 delta = now - event->ctx->timestamp;
11252 u64 time = event->ctx->time + delta;
11254 task_clock_event_update(event, time);
11257 static int task_clock_event_init(struct perf_event *event)
11259 if (event->attr.type != perf_task_clock.type)
11262 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
11266 * no branch sampling for software events
11268 if (has_branch_stack(event))
11269 return -EOPNOTSUPP;
11271 perf_swevent_init_hrtimer(event);
11276 static struct pmu perf_task_clock = {
11277 .task_ctx_nr = perf_sw_context,
11279 .capabilities = PERF_PMU_CAP_NO_NMI,
11280 .dev = PMU_NULL_DEV,
11282 .event_init = task_clock_event_init,
11283 .add = task_clock_event_add,
11284 .del = task_clock_event_del,
11285 .start = task_clock_event_start,
11286 .stop = task_clock_event_stop,
11287 .read = task_clock_event_read,
11290 static void perf_pmu_nop_void(struct pmu *pmu)
11294 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
11298 static int perf_pmu_nop_int(struct pmu *pmu)
11303 static int perf_event_nop_int(struct perf_event *event, u64 value)
11308 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
11310 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
11312 __this_cpu_write(nop_txn_flags, flags);
11314 if (flags & ~PERF_PMU_TXN_ADD)
11317 perf_pmu_disable(pmu);
11320 static int perf_pmu_commit_txn(struct pmu *pmu)
11322 unsigned int flags = __this_cpu_read(nop_txn_flags);
11324 __this_cpu_write(nop_txn_flags, 0);
11326 if (flags & ~PERF_PMU_TXN_ADD)
11329 perf_pmu_enable(pmu);
11333 static void perf_pmu_cancel_txn(struct pmu *pmu)
11335 unsigned int flags = __this_cpu_read(nop_txn_flags);
11337 __this_cpu_write(nop_txn_flags, 0);
11339 if (flags & ~PERF_PMU_TXN_ADD)
11342 perf_pmu_enable(pmu);
11345 static int perf_event_idx_default(struct perf_event *event)
11350 static void free_pmu_context(struct pmu *pmu)
11352 free_percpu(pmu->cpu_pmu_context);
11356 * Let userspace know that this PMU supports address range filtering:
11358 static ssize_t nr_addr_filters_show(struct device *dev,
11359 struct device_attribute *attr,
11362 struct pmu *pmu = dev_get_drvdata(dev);
11364 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
11366 DEVICE_ATTR_RO(nr_addr_filters);
11368 static struct idr pmu_idr;
11371 type_show(struct device *dev, struct device_attribute *attr, char *page)
11373 struct pmu *pmu = dev_get_drvdata(dev);
11375 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type);
11377 static DEVICE_ATTR_RO(type);
11380 perf_event_mux_interval_ms_show(struct device *dev,
11381 struct device_attribute *attr,
11384 struct pmu *pmu = dev_get_drvdata(dev);
11386 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms);
11389 static DEFINE_MUTEX(mux_interval_mutex);
11392 perf_event_mux_interval_ms_store(struct device *dev,
11393 struct device_attribute *attr,
11394 const char *buf, size_t count)
11396 struct pmu *pmu = dev_get_drvdata(dev);
11397 int timer, cpu, ret;
11399 ret = kstrtoint(buf, 0, &timer);
11406 /* same value, noting to do */
11407 if (timer == pmu->hrtimer_interval_ms)
11410 mutex_lock(&mux_interval_mutex);
11411 pmu->hrtimer_interval_ms = timer;
11413 /* update all cpuctx for this PMU */
11415 for_each_online_cpu(cpu) {
11416 struct perf_cpu_pmu_context *cpc;
11417 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11418 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11420 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc);
11422 cpus_read_unlock();
11423 mutex_unlock(&mux_interval_mutex);
11427 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11429 static struct attribute *pmu_dev_attrs[] = {
11430 &dev_attr_type.attr,
11431 &dev_attr_perf_event_mux_interval_ms.attr,
11432 &dev_attr_nr_addr_filters.attr,
11436 static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int n)
11438 struct device *dev = kobj_to_dev(kobj);
11439 struct pmu *pmu = dev_get_drvdata(dev);
11441 if (n == 2 && !pmu->nr_addr_filters)
11447 static struct attribute_group pmu_dev_attr_group = {
11448 .is_visible = pmu_dev_is_visible,
11449 .attrs = pmu_dev_attrs,
11452 static const struct attribute_group *pmu_dev_groups[] = {
11453 &pmu_dev_attr_group,
11457 static int pmu_bus_running;
11458 static struct bus_type pmu_bus = {
11459 .name = "event_source",
11460 .dev_groups = pmu_dev_groups,
11463 static void pmu_dev_release(struct device *dev)
11468 static int pmu_dev_alloc(struct pmu *pmu)
11472 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11476 pmu->dev->groups = pmu->attr_groups;
11477 device_initialize(pmu->dev);
11479 dev_set_drvdata(pmu->dev, pmu);
11480 pmu->dev->bus = &pmu_bus;
11481 pmu->dev->parent = pmu->parent;
11482 pmu->dev->release = pmu_dev_release;
11484 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11488 ret = device_add(pmu->dev);
11492 if (pmu->attr_update) {
11493 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11502 device_del(pmu->dev);
11505 put_device(pmu->dev);
11509 static struct lock_class_key cpuctx_mutex;
11510 static struct lock_class_key cpuctx_lock;
11512 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11514 int cpu, ret, max = PERF_TYPE_MAX;
11516 mutex_lock(&pmus_lock);
11518 pmu->pmu_disable_count = alloc_percpu(int);
11519 if (!pmu->pmu_disable_count)
11523 if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
11533 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11537 WARN_ON(type >= 0 && ret != type);
11542 if (pmu_bus_running && !pmu->dev) {
11543 ret = pmu_dev_alloc(pmu);
11549 pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
11550 if (!pmu->cpu_pmu_context)
11553 for_each_possible_cpu(cpu) {
11554 struct perf_cpu_pmu_context *cpc;
11556 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11557 __perf_init_event_pmu_context(&cpc->epc, pmu);
11558 __perf_mux_hrtimer_init(cpc, cpu);
11561 if (!pmu->start_txn) {
11562 if (pmu->pmu_enable) {
11564 * If we have pmu_enable/pmu_disable calls, install
11565 * transaction stubs that use that to try and batch
11566 * hardware accesses.
11568 pmu->start_txn = perf_pmu_start_txn;
11569 pmu->commit_txn = perf_pmu_commit_txn;
11570 pmu->cancel_txn = perf_pmu_cancel_txn;
11572 pmu->start_txn = perf_pmu_nop_txn;
11573 pmu->commit_txn = perf_pmu_nop_int;
11574 pmu->cancel_txn = perf_pmu_nop_void;
11578 if (!pmu->pmu_enable) {
11579 pmu->pmu_enable = perf_pmu_nop_void;
11580 pmu->pmu_disable = perf_pmu_nop_void;
11583 if (!pmu->check_period)
11584 pmu->check_period = perf_event_nop_int;
11586 if (!pmu->event_idx)
11587 pmu->event_idx = perf_event_idx_default;
11589 list_add_rcu(&pmu->entry, &pmus);
11590 atomic_set(&pmu->exclusive_cnt, 0);
11593 mutex_unlock(&pmus_lock);
11598 if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
11599 device_del(pmu->dev);
11600 put_device(pmu->dev);
11604 idr_remove(&pmu_idr, pmu->type);
11607 free_percpu(pmu->pmu_disable_count);
11610 EXPORT_SYMBOL_GPL(perf_pmu_register);
11612 void perf_pmu_unregister(struct pmu *pmu)
11614 mutex_lock(&pmus_lock);
11615 list_del_rcu(&pmu->entry);
11618 * We dereference the pmu list under both SRCU and regular RCU, so
11619 * synchronize against both of those.
11621 synchronize_srcu(&pmus_srcu);
11624 free_percpu(pmu->pmu_disable_count);
11625 idr_remove(&pmu_idr, pmu->type);
11626 if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
11627 if (pmu->nr_addr_filters)
11628 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11629 device_del(pmu->dev);
11630 put_device(pmu->dev);
11632 free_pmu_context(pmu);
11633 mutex_unlock(&pmus_lock);
11635 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11637 static inline bool has_extended_regs(struct perf_event *event)
11639 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11640 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11643 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11645 struct perf_event_context *ctx = NULL;
11648 if (!try_module_get(pmu->module))
11652 * A number of pmu->event_init() methods iterate the sibling_list to,
11653 * for example, validate if the group fits on the PMU. Therefore,
11654 * if this is a sibling event, acquire the ctx->mutex to protect
11655 * the sibling_list.
11657 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11659 * This ctx->mutex can nest when we're called through
11660 * inheritance. See the perf_event_ctx_lock_nested() comment.
11662 ctx = perf_event_ctx_lock_nested(event->group_leader,
11663 SINGLE_DEPTH_NESTING);
11668 ret = pmu->event_init(event);
11671 perf_event_ctx_unlock(event->group_leader, ctx);
11674 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11675 has_extended_regs(event))
11678 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11679 event_has_any_exclude_flag(event))
11682 if (ret && event->destroy)
11683 event->destroy(event);
11687 module_put(pmu->module);
11692 static struct pmu *perf_init_event(struct perf_event *event)
11694 bool extended_type = false;
11695 int idx, type, ret;
11698 idx = srcu_read_lock(&pmus_srcu);
11701 * Save original type before calling pmu->event_init() since certain
11702 * pmus overwrites event->attr.type to forward event to another pmu.
11704 event->orig_type = event->attr.type;
11706 /* Try parent's PMU first: */
11707 if (event->parent && event->parent->pmu) {
11708 pmu = event->parent->pmu;
11709 ret = perf_try_init_event(pmu, event);
11715 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11716 * are often aliases for PERF_TYPE_RAW.
11718 type = event->attr.type;
11719 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11720 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11722 type = PERF_TYPE_RAW;
11724 extended_type = true;
11725 event->attr.config &= PERF_HW_EVENT_MASK;
11731 pmu = idr_find(&pmu_idr, type);
11734 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11735 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11738 ret = perf_try_init_event(pmu, event);
11739 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11740 type = event->attr.type;
11745 pmu = ERR_PTR(ret);
11750 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11751 ret = perf_try_init_event(pmu, event);
11755 if (ret != -ENOENT) {
11756 pmu = ERR_PTR(ret);
11761 pmu = ERR_PTR(-ENOENT);
11763 srcu_read_unlock(&pmus_srcu, idx);
11768 static void attach_sb_event(struct perf_event *event)
11770 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11772 raw_spin_lock(&pel->lock);
11773 list_add_rcu(&event->sb_list, &pel->list);
11774 raw_spin_unlock(&pel->lock);
11778 * We keep a list of all !task (and therefore per-cpu) events
11779 * that need to receive side-band records.
11781 * This avoids having to scan all the various PMU per-cpu contexts
11782 * looking for them.
11784 static void account_pmu_sb_event(struct perf_event *event)
11786 if (is_sb_event(event))
11787 attach_sb_event(event);
11790 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11791 static void account_freq_event_nohz(void)
11793 #ifdef CONFIG_NO_HZ_FULL
11794 /* Lock so we don't race with concurrent unaccount */
11795 spin_lock(&nr_freq_lock);
11796 if (atomic_inc_return(&nr_freq_events) == 1)
11797 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11798 spin_unlock(&nr_freq_lock);
11802 static void account_freq_event(void)
11804 if (tick_nohz_full_enabled())
11805 account_freq_event_nohz();
11807 atomic_inc(&nr_freq_events);
11811 static void account_event(struct perf_event *event)
11818 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11820 if (event->attr.mmap || event->attr.mmap_data)
11821 atomic_inc(&nr_mmap_events);
11822 if (event->attr.build_id)
11823 atomic_inc(&nr_build_id_events);
11824 if (event->attr.comm)
11825 atomic_inc(&nr_comm_events);
11826 if (event->attr.namespaces)
11827 atomic_inc(&nr_namespaces_events);
11828 if (event->attr.cgroup)
11829 atomic_inc(&nr_cgroup_events);
11830 if (event->attr.task)
11831 atomic_inc(&nr_task_events);
11832 if (event->attr.freq)
11833 account_freq_event();
11834 if (event->attr.context_switch) {
11835 atomic_inc(&nr_switch_events);
11838 if (has_branch_stack(event))
11840 if (is_cgroup_event(event))
11842 if (event->attr.ksymbol)
11843 atomic_inc(&nr_ksymbol_events);
11844 if (event->attr.bpf_event)
11845 atomic_inc(&nr_bpf_events);
11846 if (event->attr.text_poke)
11847 atomic_inc(&nr_text_poke_events);
11851 * We need the mutex here because static_branch_enable()
11852 * must complete *before* the perf_sched_count increment
11855 if (atomic_inc_not_zero(&perf_sched_count))
11858 mutex_lock(&perf_sched_mutex);
11859 if (!atomic_read(&perf_sched_count)) {
11860 static_branch_enable(&perf_sched_events);
11862 * Guarantee that all CPUs observe they key change and
11863 * call the perf scheduling hooks before proceeding to
11864 * install events that need them.
11869 * Now that we have waited for the sync_sched(), allow further
11870 * increments to by-pass the mutex.
11872 atomic_inc(&perf_sched_count);
11873 mutex_unlock(&perf_sched_mutex);
11877 account_pmu_sb_event(event);
11881 * Allocate and initialize an event structure
11883 static struct perf_event *
11884 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11885 struct task_struct *task,
11886 struct perf_event *group_leader,
11887 struct perf_event *parent_event,
11888 perf_overflow_handler_t overflow_handler,
11889 void *context, int cgroup_fd)
11892 struct perf_event *event;
11893 struct hw_perf_event *hwc;
11894 long err = -EINVAL;
11897 if ((unsigned)cpu >= nr_cpu_ids) {
11898 if (!task || cpu != -1)
11899 return ERR_PTR(-EINVAL);
11901 if (attr->sigtrap && !task) {
11902 /* Requires a task: avoid signalling random tasks. */
11903 return ERR_PTR(-EINVAL);
11906 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11907 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11910 return ERR_PTR(-ENOMEM);
11913 * Single events are their own group leaders, with an
11914 * empty sibling list:
11917 group_leader = event;
11919 mutex_init(&event->child_mutex);
11920 INIT_LIST_HEAD(&event->child_list);
11922 INIT_LIST_HEAD(&event->event_entry);
11923 INIT_LIST_HEAD(&event->sibling_list);
11924 INIT_LIST_HEAD(&event->active_list);
11925 init_event_group(event);
11926 INIT_LIST_HEAD(&event->rb_entry);
11927 INIT_LIST_HEAD(&event->active_entry);
11928 INIT_LIST_HEAD(&event->addr_filters.list);
11929 INIT_HLIST_NODE(&event->hlist_entry);
11932 init_waitqueue_head(&event->waitq);
11933 init_irq_work(&event->pending_irq, perf_pending_irq);
11934 init_task_work(&event->pending_task, perf_pending_task);
11936 mutex_init(&event->mmap_mutex);
11937 raw_spin_lock_init(&event->addr_filters.lock);
11939 atomic_long_set(&event->refcount, 1);
11941 event->attr = *attr;
11942 event->group_leader = group_leader;
11946 event->parent = parent_event;
11948 event->ns = get_pid_ns(task_active_pid_ns(current));
11949 event->id = atomic64_inc_return(&perf_event_id);
11951 event->state = PERF_EVENT_STATE_INACTIVE;
11954 event->event_caps = parent_event->event_caps;
11957 event->attach_state = PERF_ATTACH_TASK;
11959 * XXX pmu::event_init needs to know what task to account to
11960 * and we cannot use the ctx information because we need the
11961 * pmu before we get a ctx.
11963 event->hw.target = get_task_struct(task);
11966 event->clock = &local_clock;
11968 event->clock = parent_event->clock;
11970 if (!overflow_handler && parent_event) {
11971 overflow_handler = parent_event->overflow_handler;
11972 context = parent_event->overflow_handler_context;
11973 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11974 if (overflow_handler == bpf_overflow_handler) {
11975 struct bpf_prog *prog = parent_event->prog;
11977 bpf_prog_inc(prog);
11978 event->prog = prog;
11979 event->orig_overflow_handler =
11980 parent_event->orig_overflow_handler;
11985 if (overflow_handler) {
11986 event->overflow_handler = overflow_handler;
11987 event->overflow_handler_context = context;
11988 } else if (is_write_backward(event)){
11989 event->overflow_handler = perf_event_output_backward;
11990 event->overflow_handler_context = NULL;
11992 event->overflow_handler = perf_event_output_forward;
11993 event->overflow_handler_context = NULL;
11996 perf_event__state_init(event);
12001 hwc->sample_period = attr->sample_period;
12002 if (attr->freq && attr->sample_freq)
12003 hwc->sample_period = 1;
12004 hwc->last_period = hwc->sample_period;
12006 local64_set(&hwc->period_left, hwc->sample_period);
12009 * We currently do not support PERF_SAMPLE_READ on inherited events.
12010 * See perf_output_read().
12012 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
12015 if (!has_branch_stack(event))
12016 event->attr.branch_sample_type = 0;
12018 pmu = perf_init_event(event);
12020 err = PTR_ERR(pmu);
12025 * Disallow uncore-task events. Similarly, disallow uncore-cgroup
12026 * events (they don't make sense as the cgroup will be different
12027 * on other CPUs in the uncore mask).
12029 if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) {
12034 if (event->attr.aux_output &&
12035 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
12040 if (cgroup_fd != -1) {
12041 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
12046 err = exclusive_event_init(event);
12050 if (has_addr_filter(event)) {
12051 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
12052 sizeof(struct perf_addr_filter_range),
12054 if (!event->addr_filter_ranges) {
12060 * Clone the parent's vma offsets: they are valid until exec()
12061 * even if the mm is not shared with the parent.
12063 if (event->parent) {
12064 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
12066 raw_spin_lock_irq(&ifh->lock);
12067 memcpy(event->addr_filter_ranges,
12068 event->parent->addr_filter_ranges,
12069 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
12070 raw_spin_unlock_irq(&ifh->lock);
12073 /* force hw sync on the address filters */
12074 event->addr_filters_gen = 1;
12077 if (!event->parent) {
12078 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
12079 err = get_callchain_buffers(attr->sample_max_stack);
12081 goto err_addr_filters;
12085 err = security_perf_event_alloc(event);
12087 goto err_callchain_buffer;
12089 /* symmetric to unaccount_event() in _free_event() */
12090 account_event(event);
12094 err_callchain_buffer:
12095 if (!event->parent) {
12096 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
12097 put_callchain_buffers();
12100 kfree(event->addr_filter_ranges);
12103 exclusive_event_destroy(event);
12106 if (is_cgroup_event(event))
12107 perf_detach_cgroup(event);
12108 if (event->destroy)
12109 event->destroy(event);
12110 module_put(pmu->module);
12112 if (event->hw.target)
12113 put_task_struct(event->hw.target);
12114 call_rcu(&event->rcu_head, free_event_rcu);
12116 return ERR_PTR(err);
12119 static int perf_copy_attr(struct perf_event_attr __user *uattr,
12120 struct perf_event_attr *attr)
12125 /* Zero the full structure, so that a short copy will be nice. */
12126 memset(attr, 0, sizeof(*attr));
12128 ret = get_user(size, &uattr->size);
12132 /* ABI compatibility quirk: */
12134 size = PERF_ATTR_SIZE_VER0;
12135 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
12138 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
12147 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
12150 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
12153 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
12156 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
12157 u64 mask = attr->branch_sample_type;
12159 /* only using defined bits */
12160 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
12163 /* at least one branch bit must be set */
12164 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
12167 /* propagate priv level, when not set for branch */
12168 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
12170 /* exclude_kernel checked on syscall entry */
12171 if (!attr->exclude_kernel)
12172 mask |= PERF_SAMPLE_BRANCH_KERNEL;
12174 if (!attr->exclude_user)
12175 mask |= PERF_SAMPLE_BRANCH_USER;
12177 if (!attr->exclude_hv)
12178 mask |= PERF_SAMPLE_BRANCH_HV;
12180 * adjust user setting (for HW filter setup)
12182 attr->branch_sample_type = mask;
12184 /* privileged levels capture (kernel, hv): check permissions */
12185 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
12186 ret = perf_allow_kernel(attr);
12192 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
12193 ret = perf_reg_validate(attr->sample_regs_user);
12198 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
12199 if (!arch_perf_have_user_stack_dump())
12203 * We have __u32 type for the size, but so far
12204 * we can only use __u16 as maximum due to the
12205 * __u16 sample size limit.
12207 if (attr->sample_stack_user >= USHRT_MAX)
12209 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
12213 if (!attr->sample_max_stack)
12214 attr->sample_max_stack = sysctl_perf_event_max_stack;
12216 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
12217 ret = perf_reg_validate(attr->sample_regs_intr);
12219 #ifndef CONFIG_CGROUP_PERF
12220 if (attr->sample_type & PERF_SAMPLE_CGROUP)
12223 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
12224 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
12227 if (!attr->inherit && attr->inherit_thread)
12230 if (attr->remove_on_exec && attr->enable_on_exec)
12233 if (attr->sigtrap && !attr->remove_on_exec)
12240 put_user(sizeof(*attr), &uattr->size);
12245 static void mutex_lock_double(struct mutex *a, struct mutex *b)
12251 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
12255 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
12257 struct perf_buffer *rb = NULL;
12260 if (!output_event) {
12261 mutex_lock(&event->mmap_mutex);
12265 /* don't allow circular references */
12266 if (event == output_event)
12270 * Don't allow cross-cpu buffers
12272 if (output_event->cpu != event->cpu)
12276 * If its not a per-cpu rb, it must be the same task.
12278 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
12282 * Mixing clocks in the same buffer is trouble you don't need.
12284 if (output_event->clock != event->clock)
12288 * Either writing ring buffer from beginning or from end.
12289 * Mixing is not allowed.
12291 if (is_write_backward(output_event) != is_write_backward(event))
12295 * If both events generate aux data, they must be on the same PMU
12297 if (has_aux(event) && has_aux(output_event) &&
12298 event->pmu != output_event->pmu)
12302 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
12303 * output_event is already on rb->event_list, and the list iteration
12304 * restarts after every removal, it is guaranteed this new event is
12305 * observed *OR* if output_event is already removed, it's guaranteed we
12306 * observe !rb->mmap_count.
12308 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
12310 /* Can't redirect output if we've got an active mmap() */
12311 if (atomic_read(&event->mmap_count))
12314 if (output_event) {
12315 /* get the rb we want to redirect to */
12316 rb = ring_buffer_get(output_event);
12320 /* did we race against perf_mmap_close() */
12321 if (!atomic_read(&rb->mmap_count)) {
12322 ring_buffer_put(rb);
12327 ring_buffer_attach(event, rb);
12331 mutex_unlock(&event->mmap_mutex);
12333 mutex_unlock(&output_event->mmap_mutex);
12339 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
12341 bool nmi_safe = false;
12344 case CLOCK_MONOTONIC:
12345 event->clock = &ktime_get_mono_fast_ns;
12349 case CLOCK_MONOTONIC_RAW:
12350 event->clock = &ktime_get_raw_fast_ns;
12354 case CLOCK_REALTIME:
12355 event->clock = &ktime_get_real_ns;
12358 case CLOCK_BOOTTIME:
12359 event->clock = &ktime_get_boottime_ns;
12363 event->clock = &ktime_get_clocktai_ns;
12370 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12377 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12379 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12380 bool is_capable = perfmon_capable();
12382 if (attr->sigtrap) {
12384 * perf_event_attr::sigtrap sends signals to the other task.
12385 * Require the current task to also have CAP_KILL.
12388 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12392 * If the required capabilities aren't available, checks for
12393 * ptrace permissions: upgrade to ATTACH, since sending signals
12394 * can effectively change the target task.
12396 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12400 * Preserve ptrace permission check for backwards compatibility. The
12401 * ptrace check also includes checks that the current task and other
12402 * task have matching uids, and is therefore not done here explicitly.
12404 return is_capable || ptrace_may_access(task, ptrace_mode);
12408 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12410 * @attr_uptr: event_id type attributes for monitoring/sampling
12413 * @group_fd: group leader event fd
12414 * @flags: perf event open flags
12416 SYSCALL_DEFINE5(perf_event_open,
12417 struct perf_event_attr __user *, attr_uptr,
12418 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12420 struct perf_event *group_leader = NULL, *output_event = NULL;
12421 struct perf_event_pmu_context *pmu_ctx;
12422 struct perf_event *event, *sibling;
12423 struct perf_event_attr attr;
12424 struct perf_event_context *ctx;
12425 struct file *event_file = NULL;
12426 struct fd group = {NULL, 0};
12427 struct task_struct *task = NULL;
12430 int move_group = 0;
12432 int f_flags = O_RDWR;
12433 int cgroup_fd = -1;
12435 /* for future expandability... */
12436 if (flags & ~PERF_FLAG_ALL)
12439 err = perf_copy_attr(attr_uptr, &attr);
12443 /* Do we allow access to perf_event_open(2) ? */
12444 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12448 if (!attr.exclude_kernel) {
12449 err = perf_allow_kernel(&attr);
12454 if (attr.namespaces) {
12455 if (!perfmon_capable())
12460 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12463 if (attr.sample_period & (1ULL << 63))
12467 /* Only privileged users can get physical addresses */
12468 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12469 err = perf_allow_kernel(&attr);
12474 /* REGS_INTR can leak data, lockdown must prevent this */
12475 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12476 err = security_locked_down(LOCKDOWN_PERF);
12482 * In cgroup mode, the pid argument is used to pass the fd
12483 * opened to the cgroup directory in cgroupfs. The cpu argument
12484 * designates the cpu on which to monitor threads from that
12487 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12490 if (flags & PERF_FLAG_FD_CLOEXEC)
12491 f_flags |= O_CLOEXEC;
12493 event_fd = get_unused_fd_flags(f_flags);
12497 if (group_fd != -1) {
12498 err = perf_fget_light(group_fd, &group);
12501 group_leader = group.file->private_data;
12502 if (flags & PERF_FLAG_FD_OUTPUT)
12503 output_event = group_leader;
12504 if (flags & PERF_FLAG_FD_NO_GROUP)
12505 group_leader = NULL;
12508 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12509 task = find_lively_task_by_vpid(pid);
12510 if (IS_ERR(task)) {
12511 err = PTR_ERR(task);
12516 if (task && group_leader &&
12517 group_leader->attr.inherit != attr.inherit) {
12522 if (flags & PERF_FLAG_PID_CGROUP)
12525 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12526 NULL, NULL, cgroup_fd);
12527 if (IS_ERR(event)) {
12528 err = PTR_ERR(event);
12532 if (is_sampling_event(event)) {
12533 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12540 * Special case software events and allow them to be part of
12541 * any hardware group.
12545 if (attr.use_clockid) {
12546 err = perf_event_set_clock(event, attr.clockid);
12551 if (pmu->task_ctx_nr == perf_sw_context)
12552 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12555 err = down_read_interruptible(&task->signal->exec_update_lock);
12560 * We must hold exec_update_lock across this and any potential
12561 * perf_install_in_context() call for this new event to
12562 * serialize against exec() altering our credentials (and the
12563 * perf_event_exit_task() that could imply).
12566 if (!perf_check_permission(&attr, task))
12571 * Get the target context (task or percpu):
12573 ctx = find_get_context(task, event);
12575 err = PTR_ERR(ctx);
12579 mutex_lock(&ctx->mutex);
12581 if (ctx->task == TASK_TOMBSTONE) {
12588 * Check if the @cpu we're creating an event for is online.
12590 * We use the perf_cpu_context::ctx::mutex to serialize against
12591 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12593 struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
12595 if (!cpuctx->online) {
12601 if (group_leader) {
12605 * Do not allow a recursive hierarchy (this new sibling
12606 * becoming part of another group-sibling):
12608 if (group_leader->group_leader != group_leader)
12611 /* All events in a group should have the same clock */
12612 if (group_leader->clock != event->clock)
12616 * Make sure we're both events for the same CPU;
12617 * grouping events for different CPUs is broken; since
12618 * you can never concurrently schedule them anyhow.
12620 if (group_leader->cpu != event->cpu)
12624 * Make sure we're both on the same context; either task or cpu.
12626 if (group_leader->ctx != ctx)
12630 * Only a group leader can be exclusive or pinned
12632 if (attr.exclusive || attr.pinned)
12635 if (is_software_event(event) &&
12636 !in_software_context(group_leader)) {
12638 * If the event is a sw event, but the group_leader
12639 * is on hw context.
12641 * Allow the addition of software events to hw
12642 * groups, this is safe because software events
12643 * never fail to schedule.
12645 * Note the comment that goes with struct
12646 * perf_event_pmu_context.
12648 pmu = group_leader->pmu_ctx->pmu;
12649 } else if (!is_software_event(event)) {
12650 if (is_software_event(group_leader) &&
12651 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12653 * In case the group is a pure software group, and we
12654 * try to add a hardware event, move the whole group to
12655 * the hardware context.
12660 /* Don't allow group of multiple hw events from different pmus */
12661 if (!in_software_context(group_leader) &&
12662 group_leader->pmu_ctx->pmu != pmu)
12668 * Now that we're certain of the pmu; find the pmu_ctx.
12670 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12671 if (IS_ERR(pmu_ctx)) {
12672 err = PTR_ERR(pmu_ctx);
12675 event->pmu_ctx = pmu_ctx;
12677 if (output_event) {
12678 err = perf_event_set_output(event, output_event);
12683 if (!perf_event_validate_size(event)) {
12688 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12694 * Must be under the same ctx::mutex as perf_install_in_context(),
12695 * because we need to serialize with concurrent event creation.
12697 if (!exclusive_event_installable(event, ctx)) {
12702 WARN_ON_ONCE(ctx->parent_ctx);
12704 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags);
12705 if (IS_ERR(event_file)) {
12706 err = PTR_ERR(event_file);
12712 * This is the point on no return; we cannot fail hereafter. This is
12713 * where we start modifying current state.
12717 perf_remove_from_context(group_leader, 0);
12718 put_pmu_ctx(group_leader->pmu_ctx);
12720 for_each_sibling_event(sibling, group_leader) {
12721 perf_remove_from_context(sibling, 0);
12722 put_pmu_ctx(sibling->pmu_ctx);
12726 * Install the group siblings before the group leader.
12728 * Because a group leader will try and install the entire group
12729 * (through the sibling list, which is still in-tact), we can
12730 * end up with siblings installed in the wrong context.
12732 * By installing siblings first we NO-OP because they're not
12733 * reachable through the group lists.
12735 for_each_sibling_event(sibling, group_leader) {
12736 sibling->pmu_ctx = pmu_ctx;
12737 get_pmu_ctx(pmu_ctx);
12738 perf_event__state_init(sibling);
12739 perf_install_in_context(ctx, sibling, sibling->cpu);
12743 * Removing from the context ends up with disabled
12744 * event. What we want here is event in the initial
12745 * startup state, ready to be add into new context.
12747 group_leader->pmu_ctx = pmu_ctx;
12748 get_pmu_ctx(pmu_ctx);
12749 perf_event__state_init(group_leader);
12750 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12754 * Precalculate sample_data sizes; do while holding ctx::mutex such
12755 * that we're serialized against further additions and before
12756 * perf_install_in_context() which is the point the event is active and
12757 * can use these values.
12759 perf_event__header_size(event);
12760 perf_event__id_header_size(event);
12762 event->owner = current;
12764 perf_install_in_context(ctx, event, event->cpu);
12765 perf_unpin_context(ctx);
12767 mutex_unlock(&ctx->mutex);
12770 up_read(&task->signal->exec_update_lock);
12771 put_task_struct(task);
12774 mutex_lock(¤t->perf_event_mutex);
12775 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12776 mutex_unlock(¤t->perf_event_mutex);
12779 * Drop the reference on the group_event after placing the
12780 * new event on the sibling_list. This ensures destruction
12781 * of the group leader will find the pointer to itself in
12782 * perf_group_detach().
12785 fd_install(event_fd, event_file);
12789 put_pmu_ctx(event->pmu_ctx);
12790 event->pmu_ctx = NULL; /* _free_event() */
12792 mutex_unlock(&ctx->mutex);
12793 perf_unpin_context(ctx);
12797 up_read(&task->signal->exec_update_lock);
12802 put_task_struct(task);
12806 put_unused_fd(event_fd);
12811 * perf_event_create_kernel_counter
12813 * @attr: attributes of the counter to create
12814 * @cpu: cpu in which the counter is bound
12815 * @task: task to profile (NULL for percpu)
12816 * @overflow_handler: callback to trigger when we hit the event
12817 * @context: context data could be used in overflow_handler callback
12819 struct perf_event *
12820 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12821 struct task_struct *task,
12822 perf_overflow_handler_t overflow_handler,
12825 struct perf_event_pmu_context *pmu_ctx;
12826 struct perf_event_context *ctx;
12827 struct perf_event *event;
12832 * Grouping is not supported for kernel events, neither is 'AUX',
12833 * make sure the caller's intentions are adjusted.
12835 if (attr->aux_output)
12836 return ERR_PTR(-EINVAL);
12838 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12839 overflow_handler, context, -1);
12840 if (IS_ERR(event)) {
12841 err = PTR_ERR(event);
12845 /* Mark owner so we could distinguish it from user events. */
12846 event->owner = TASK_TOMBSTONE;
12849 if (pmu->task_ctx_nr == perf_sw_context)
12850 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12853 * Get the target context (task or percpu):
12855 ctx = find_get_context(task, event);
12857 err = PTR_ERR(ctx);
12861 WARN_ON_ONCE(ctx->parent_ctx);
12862 mutex_lock(&ctx->mutex);
12863 if (ctx->task == TASK_TOMBSTONE) {
12868 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12869 if (IS_ERR(pmu_ctx)) {
12870 err = PTR_ERR(pmu_ctx);
12873 event->pmu_ctx = pmu_ctx;
12877 * Check if the @cpu we're creating an event for is online.
12879 * We use the perf_cpu_context::ctx::mutex to serialize against
12880 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12882 struct perf_cpu_context *cpuctx =
12883 container_of(ctx, struct perf_cpu_context, ctx);
12884 if (!cpuctx->online) {
12890 if (!exclusive_event_installable(event, ctx)) {
12895 perf_install_in_context(ctx, event, event->cpu);
12896 perf_unpin_context(ctx);
12897 mutex_unlock(&ctx->mutex);
12902 put_pmu_ctx(pmu_ctx);
12903 event->pmu_ctx = NULL; /* _free_event() */
12905 mutex_unlock(&ctx->mutex);
12906 perf_unpin_context(ctx);
12911 return ERR_PTR(err);
12913 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12915 static void __perf_pmu_remove(struct perf_event_context *ctx,
12916 int cpu, struct pmu *pmu,
12917 struct perf_event_groups *groups,
12918 struct list_head *events)
12920 struct perf_event *event, *sibling;
12922 perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
12923 perf_remove_from_context(event, 0);
12924 put_pmu_ctx(event->pmu_ctx);
12925 list_add(&event->migrate_entry, events);
12927 for_each_sibling_event(sibling, event) {
12928 perf_remove_from_context(sibling, 0);
12929 put_pmu_ctx(sibling->pmu_ctx);
12930 list_add(&sibling->migrate_entry, events);
12935 static void __perf_pmu_install_event(struct pmu *pmu,
12936 struct perf_event_context *ctx,
12937 int cpu, struct perf_event *event)
12939 struct perf_event_pmu_context *epc;
12940 struct perf_event_context *old_ctx = event->ctx;
12942 get_ctx(ctx); /* normally find_get_context() */
12945 epc = find_get_pmu_context(pmu, ctx, event);
12946 event->pmu_ctx = epc;
12948 if (event->state >= PERF_EVENT_STATE_OFF)
12949 event->state = PERF_EVENT_STATE_INACTIVE;
12950 perf_install_in_context(ctx, event, cpu);
12953 * Now that event->ctx is updated and visible, put the old ctx.
12958 static void __perf_pmu_install(struct perf_event_context *ctx,
12959 int cpu, struct pmu *pmu, struct list_head *events)
12961 struct perf_event *event, *tmp;
12964 * Re-instate events in 2 passes.
12966 * Skip over group leaders and only install siblings on this first
12967 * pass, siblings will not get enabled without a leader, however a
12968 * leader will enable its siblings, even if those are still on the old
12971 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12972 if (event->group_leader == event)
12975 list_del(&event->migrate_entry);
12976 __perf_pmu_install_event(pmu, ctx, cpu, event);
12980 * Once all the siblings are setup properly, install the group leaders
12983 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12984 list_del(&event->migrate_entry);
12985 __perf_pmu_install_event(pmu, ctx, cpu, event);
12989 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12991 struct perf_event_context *src_ctx, *dst_ctx;
12995 * Since per-cpu context is persistent, no need to grab an extra
12998 src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx;
12999 dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx;
13002 * See perf_event_ctx_lock() for comments on the details
13003 * of swizzling perf_event::ctx.
13005 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
13007 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events);
13008 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events);
13010 if (!list_empty(&events)) {
13012 * Wait for the events to quiesce before re-instating them.
13016 __perf_pmu_install(dst_ctx, dst_cpu, pmu, &events);
13019 mutex_unlock(&dst_ctx->mutex);
13020 mutex_unlock(&src_ctx->mutex);
13022 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
13024 static void sync_child_event(struct perf_event *child_event)
13026 struct perf_event *parent_event = child_event->parent;
13029 if (child_event->attr.inherit_stat) {
13030 struct task_struct *task = child_event->ctx->task;
13032 if (task && task != TASK_TOMBSTONE)
13033 perf_event_read_event(child_event, task);
13036 child_val = perf_event_count(child_event);
13039 * Add back the child's count to the parent's count:
13041 atomic64_add(child_val, &parent_event->child_count);
13042 atomic64_add(child_event->total_time_enabled,
13043 &parent_event->child_total_time_enabled);
13044 atomic64_add(child_event->total_time_running,
13045 &parent_event->child_total_time_running);
13049 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
13051 struct perf_event *parent_event = event->parent;
13052 unsigned long detach_flags = 0;
13054 if (parent_event) {
13056 * Do not destroy the 'original' grouping; because of the
13057 * context switch optimization the original events could've
13058 * ended up in a random child task.
13060 * If we were to destroy the original group, all group related
13061 * operations would cease to function properly after this
13062 * random child dies.
13064 * Do destroy all inherited groups, we don't care about those
13065 * and being thorough is better.
13067 detach_flags = DETACH_GROUP | DETACH_CHILD;
13068 mutex_lock(&parent_event->child_mutex);
13071 perf_remove_from_context(event, detach_flags);
13073 raw_spin_lock_irq(&ctx->lock);
13074 if (event->state > PERF_EVENT_STATE_EXIT)
13075 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
13076 raw_spin_unlock_irq(&ctx->lock);
13079 * Child events can be freed.
13081 if (parent_event) {
13082 mutex_unlock(&parent_event->child_mutex);
13084 * Kick perf_poll() for is_event_hup();
13086 perf_event_wakeup(parent_event);
13088 put_event(parent_event);
13093 * Parent events are governed by their filedesc, retain them.
13095 perf_event_wakeup(event);
13098 static void perf_event_exit_task_context(struct task_struct *child)
13100 struct perf_event_context *child_ctx, *clone_ctx = NULL;
13101 struct perf_event *child_event, *next;
13103 WARN_ON_ONCE(child != current);
13105 child_ctx = perf_pin_task_context(child);
13110 * In order to reduce the amount of tricky in ctx tear-down, we hold
13111 * ctx::mutex over the entire thing. This serializes against almost
13112 * everything that wants to access the ctx.
13114 * The exception is sys_perf_event_open() /
13115 * perf_event_create_kernel_count() which does find_get_context()
13116 * without ctx::mutex (it cannot because of the move_group double mutex
13117 * lock thing). See the comments in perf_install_in_context().
13119 mutex_lock(&child_ctx->mutex);
13122 * In a single ctx::lock section, de-schedule the events and detach the
13123 * context from the task such that we cannot ever get it scheduled back
13126 raw_spin_lock_irq(&child_ctx->lock);
13127 task_ctx_sched_out(child_ctx, EVENT_ALL);
13130 * Now that the context is inactive, destroy the task <-> ctx relation
13131 * and mark the context dead.
13133 RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
13134 put_ctx(child_ctx); /* cannot be last */
13135 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
13136 put_task_struct(current); /* cannot be last */
13138 clone_ctx = unclone_ctx(child_ctx);
13139 raw_spin_unlock_irq(&child_ctx->lock);
13142 put_ctx(clone_ctx);
13145 * Report the task dead after unscheduling the events so that we
13146 * won't get any samples after PERF_RECORD_EXIT. We can however still
13147 * get a few PERF_RECORD_READ events.
13149 perf_event_task(child, child_ctx, 0);
13151 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
13152 perf_event_exit_event(child_event, child_ctx);
13154 mutex_unlock(&child_ctx->mutex);
13156 put_ctx(child_ctx);
13160 * When a child task exits, feed back event values to parent events.
13162 * Can be called with exec_update_lock held when called from
13163 * setup_new_exec().
13165 void perf_event_exit_task(struct task_struct *child)
13167 struct perf_event *event, *tmp;
13169 mutex_lock(&child->perf_event_mutex);
13170 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
13172 list_del_init(&event->owner_entry);
13175 * Ensure the list deletion is visible before we clear
13176 * the owner, closes a race against perf_release() where
13177 * we need to serialize on the owner->perf_event_mutex.
13179 smp_store_release(&event->owner, NULL);
13181 mutex_unlock(&child->perf_event_mutex);
13183 perf_event_exit_task_context(child);
13186 * The perf_event_exit_task_context calls perf_event_task
13187 * with child's task_ctx, which generates EXIT events for
13188 * child contexts and sets child->perf_event_ctxp[] to NULL.
13189 * At this point we need to send EXIT events to cpu contexts.
13191 perf_event_task(child, NULL, 0);
13194 static void perf_free_event(struct perf_event *event,
13195 struct perf_event_context *ctx)
13197 struct perf_event *parent = event->parent;
13199 if (WARN_ON_ONCE(!parent))
13202 mutex_lock(&parent->child_mutex);
13203 list_del_init(&event->child_list);
13204 mutex_unlock(&parent->child_mutex);
13208 raw_spin_lock_irq(&ctx->lock);
13209 perf_group_detach(event);
13210 list_del_event(event, ctx);
13211 raw_spin_unlock_irq(&ctx->lock);
13216 * Free a context as created by inheritance by perf_event_init_task() below,
13217 * used by fork() in case of fail.
13219 * Even though the task has never lived, the context and events have been
13220 * exposed through the child_list, so we must take care tearing it all down.
13222 void perf_event_free_task(struct task_struct *task)
13224 struct perf_event_context *ctx;
13225 struct perf_event *event, *tmp;
13227 ctx = rcu_access_pointer(task->perf_event_ctxp);
13231 mutex_lock(&ctx->mutex);
13232 raw_spin_lock_irq(&ctx->lock);
13234 * Destroy the task <-> ctx relation and mark the context dead.
13236 * This is important because even though the task hasn't been
13237 * exposed yet the context has been (through child_list).
13239 RCU_INIT_POINTER(task->perf_event_ctxp, NULL);
13240 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
13241 put_task_struct(task); /* cannot be last */
13242 raw_spin_unlock_irq(&ctx->lock);
13245 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
13246 perf_free_event(event, ctx);
13248 mutex_unlock(&ctx->mutex);
13251 * perf_event_release_kernel() could've stolen some of our
13252 * child events and still have them on its free_list. In that
13253 * case we must wait for these events to have been freed (in
13254 * particular all their references to this task must've been
13257 * Without this copy_process() will unconditionally free this
13258 * task (irrespective of its reference count) and
13259 * _free_event()'s put_task_struct(event->hw.target) will be a
13262 * Wait for all events to drop their context reference.
13264 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
13265 put_ctx(ctx); /* must be last */
13268 void perf_event_delayed_put(struct task_struct *task)
13270 WARN_ON_ONCE(task->perf_event_ctxp);
13273 struct file *perf_event_get(unsigned int fd)
13275 struct file *file = fget(fd);
13277 return ERR_PTR(-EBADF);
13279 if (file->f_op != &perf_fops) {
13281 return ERR_PTR(-EBADF);
13287 const struct perf_event *perf_get_event(struct file *file)
13289 if (file->f_op != &perf_fops)
13290 return ERR_PTR(-EINVAL);
13292 return file->private_data;
13295 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
13298 return ERR_PTR(-EINVAL);
13300 return &event->attr;
13304 * Inherit an event from parent task to child task.
13307 * - valid pointer on success
13308 * - NULL for orphaned events
13309 * - IS_ERR() on error
13311 static struct perf_event *
13312 inherit_event(struct perf_event *parent_event,
13313 struct task_struct *parent,
13314 struct perf_event_context *parent_ctx,
13315 struct task_struct *child,
13316 struct perf_event *group_leader,
13317 struct perf_event_context *child_ctx)
13319 enum perf_event_state parent_state = parent_event->state;
13320 struct perf_event_pmu_context *pmu_ctx;
13321 struct perf_event *child_event;
13322 unsigned long flags;
13325 * Instead of creating recursive hierarchies of events,
13326 * we link inherited events back to the original parent,
13327 * which has a filp for sure, which we use as the reference
13330 if (parent_event->parent)
13331 parent_event = parent_event->parent;
13333 child_event = perf_event_alloc(&parent_event->attr,
13336 group_leader, parent_event,
13338 if (IS_ERR(child_event))
13339 return child_event;
13341 pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
13342 if (IS_ERR(pmu_ctx)) {
13343 free_event(child_event);
13344 return ERR_CAST(pmu_ctx);
13346 child_event->pmu_ctx = pmu_ctx;
13349 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13350 * must be under the same lock in order to serialize against
13351 * perf_event_release_kernel(), such that either we must observe
13352 * is_orphaned_event() or they will observe us on the child_list.
13354 mutex_lock(&parent_event->child_mutex);
13355 if (is_orphaned_event(parent_event) ||
13356 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13357 mutex_unlock(&parent_event->child_mutex);
13358 /* task_ctx_data is freed with child_ctx */
13359 free_event(child_event);
13363 get_ctx(child_ctx);
13366 * Make the child state follow the state of the parent event,
13367 * not its attr.disabled bit. We hold the parent's mutex,
13368 * so we won't race with perf_event_{en, dis}able_family.
13370 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13371 child_event->state = PERF_EVENT_STATE_INACTIVE;
13373 child_event->state = PERF_EVENT_STATE_OFF;
13375 if (parent_event->attr.freq) {
13376 u64 sample_period = parent_event->hw.sample_period;
13377 struct hw_perf_event *hwc = &child_event->hw;
13379 hwc->sample_period = sample_period;
13380 hwc->last_period = sample_period;
13382 local64_set(&hwc->period_left, sample_period);
13385 child_event->ctx = child_ctx;
13386 child_event->overflow_handler = parent_event->overflow_handler;
13387 child_event->overflow_handler_context
13388 = parent_event->overflow_handler_context;
13391 * Precalculate sample_data sizes
13393 perf_event__header_size(child_event);
13394 perf_event__id_header_size(child_event);
13397 * Link it up in the child's context:
13399 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13400 add_event_to_ctx(child_event, child_ctx);
13401 child_event->attach_state |= PERF_ATTACH_CHILD;
13402 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13405 * Link this into the parent event's child list
13407 list_add_tail(&child_event->child_list, &parent_event->child_list);
13408 mutex_unlock(&parent_event->child_mutex);
13410 return child_event;
13414 * Inherits an event group.
13416 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13417 * This matches with perf_event_release_kernel() removing all child events.
13423 static int inherit_group(struct perf_event *parent_event,
13424 struct task_struct *parent,
13425 struct perf_event_context *parent_ctx,
13426 struct task_struct *child,
13427 struct perf_event_context *child_ctx)
13429 struct perf_event *leader;
13430 struct perf_event *sub;
13431 struct perf_event *child_ctr;
13433 leader = inherit_event(parent_event, parent, parent_ctx,
13434 child, NULL, child_ctx);
13435 if (IS_ERR(leader))
13436 return PTR_ERR(leader);
13438 * @leader can be NULL here because of is_orphaned_event(). In this
13439 * case inherit_event() will create individual events, similar to what
13440 * perf_group_detach() would do anyway.
13442 for_each_sibling_event(sub, parent_event) {
13443 child_ctr = inherit_event(sub, parent, parent_ctx,
13444 child, leader, child_ctx);
13445 if (IS_ERR(child_ctr))
13446 return PTR_ERR(child_ctr);
13448 if (sub->aux_event == parent_event && child_ctr &&
13449 !perf_get_aux_event(child_ctr, leader))
13453 leader->group_generation = parent_event->group_generation;
13458 * Creates the child task context and tries to inherit the event-group.
13460 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13461 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13462 * consistent with perf_event_release_kernel() removing all child events.
13469 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13470 struct perf_event_context *parent_ctx,
13471 struct task_struct *child,
13472 u64 clone_flags, int *inherited_all)
13474 struct perf_event_context *child_ctx;
13477 if (!event->attr.inherit ||
13478 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13479 /* Do not inherit if sigtrap and signal handlers were cleared. */
13480 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13481 *inherited_all = 0;
13485 child_ctx = child->perf_event_ctxp;
13488 * This is executed from the parent task context, so
13489 * inherit events that have been marked for cloning.
13490 * First allocate and initialize a context for the
13493 child_ctx = alloc_perf_context(child);
13497 child->perf_event_ctxp = child_ctx;
13500 ret = inherit_group(event, parent, parent_ctx, child, child_ctx);
13502 *inherited_all = 0;
13508 * Initialize the perf_event context in task_struct
13510 static int perf_event_init_context(struct task_struct *child, u64 clone_flags)
13512 struct perf_event_context *child_ctx, *parent_ctx;
13513 struct perf_event_context *cloned_ctx;
13514 struct perf_event *event;
13515 struct task_struct *parent = current;
13516 int inherited_all = 1;
13517 unsigned long flags;
13520 if (likely(!parent->perf_event_ctxp))
13524 * If the parent's context is a clone, pin it so it won't get
13525 * swapped under us.
13527 parent_ctx = perf_pin_task_context(parent);
13532 * No need to check if parent_ctx != NULL here; since we saw
13533 * it non-NULL earlier, the only reason for it to become NULL
13534 * is if we exit, and since we're currently in the middle of
13535 * a fork we can't be exiting at the same time.
13539 * Lock the parent list. No need to lock the child - not PID
13540 * hashed yet and not running, so nobody can access it.
13542 mutex_lock(&parent_ctx->mutex);
13545 * We dont have to disable NMIs - we are only looking at
13546 * the list, not manipulating it:
13548 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13549 ret = inherit_task_group(event, parent, parent_ctx,
13550 child, clone_flags, &inherited_all);
13556 * We can't hold ctx->lock when iterating the ->flexible_group list due
13557 * to allocations, but we need to prevent rotation because
13558 * rotate_ctx() will change the list from interrupt context.
13560 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13561 parent_ctx->rotate_disable = 1;
13562 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13564 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13565 ret = inherit_task_group(event, parent, parent_ctx,
13566 child, clone_flags, &inherited_all);
13571 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13572 parent_ctx->rotate_disable = 0;
13574 child_ctx = child->perf_event_ctxp;
13576 if (child_ctx && inherited_all) {
13578 * Mark the child context as a clone of the parent
13579 * context, or of whatever the parent is a clone of.
13581 * Note that if the parent is a clone, the holding of
13582 * parent_ctx->lock avoids it from being uncloned.
13584 cloned_ctx = parent_ctx->parent_ctx;
13586 child_ctx->parent_ctx = cloned_ctx;
13587 child_ctx->parent_gen = parent_ctx->parent_gen;
13589 child_ctx->parent_ctx = parent_ctx;
13590 child_ctx->parent_gen = parent_ctx->generation;
13592 get_ctx(child_ctx->parent_ctx);
13595 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13597 mutex_unlock(&parent_ctx->mutex);
13599 perf_unpin_context(parent_ctx);
13600 put_ctx(parent_ctx);
13606 * Initialize the perf_event context in task_struct
13608 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13612 child->perf_event_ctxp = NULL;
13613 mutex_init(&child->perf_event_mutex);
13614 INIT_LIST_HEAD(&child->perf_event_list);
13616 ret = perf_event_init_context(child, clone_flags);
13618 perf_event_free_task(child);
13625 static void __init perf_event_init_all_cpus(void)
13627 struct swevent_htable *swhash;
13628 struct perf_cpu_context *cpuctx;
13631 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13633 for_each_possible_cpu(cpu) {
13634 swhash = &per_cpu(swevent_htable, cpu);
13635 mutex_init(&swhash->hlist_mutex);
13637 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13638 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13640 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13642 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13643 __perf_event_init_context(&cpuctx->ctx);
13644 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
13645 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
13646 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
13647 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
13648 cpuctx->heap = cpuctx->heap_default;
13652 static void perf_swevent_init_cpu(unsigned int cpu)
13654 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13656 mutex_lock(&swhash->hlist_mutex);
13657 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13658 struct swevent_hlist *hlist;
13660 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13662 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13664 mutex_unlock(&swhash->hlist_mutex);
13667 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13668 static void __perf_event_exit_context(void *__info)
13670 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
13671 struct perf_event_context *ctx = __info;
13672 struct perf_event *event;
13674 raw_spin_lock(&ctx->lock);
13675 ctx_sched_out(ctx, EVENT_TIME);
13676 list_for_each_entry(event, &ctx->event_list, event_entry)
13677 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13678 raw_spin_unlock(&ctx->lock);
13681 static void perf_event_exit_cpu_context(int cpu)
13683 struct perf_cpu_context *cpuctx;
13684 struct perf_event_context *ctx;
13686 // XXX simplify cpuctx->online
13687 mutex_lock(&pmus_lock);
13688 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13689 ctx = &cpuctx->ctx;
13691 mutex_lock(&ctx->mutex);
13692 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13693 cpuctx->online = 0;
13694 mutex_unlock(&ctx->mutex);
13695 cpumask_clear_cpu(cpu, perf_online_mask);
13696 mutex_unlock(&pmus_lock);
13700 static void perf_event_exit_cpu_context(int cpu) { }
13704 int perf_event_init_cpu(unsigned int cpu)
13706 struct perf_cpu_context *cpuctx;
13707 struct perf_event_context *ctx;
13709 perf_swevent_init_cpu(cpu);
13711 mutex_lock(&pmus_lock);
13712 cpumask_set_cpu(cpu, perf_online_mask);
13713 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13714 ctx = &cpuctx->ctx;
13716 mutex_lock(&ctx->mutex);
13717 cpuctx->online = 1;
13718 mutex_unlock(&ctx->mutex);
13719 mutex_unlock(&pmus_lock);
13724 int perf_event_exit_cpu(unsigned int cpu)
13726 perf_event_exit_cpu_context(cpu);
13731 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13735 for_each_online_cpu(cpu)
13736 perf_event_exit_cpu(cpu);
13742 * Run the perf reboot notifier at the very last possible moment so that
13743 * the generic watchdog code runs as long as possible.
13745 static struct notifier_block perf_reboot_notifier = {
13746 .notifier_call = perf_reboot,
13747 .priority = INT_MIN,
13750 void __init perf_event_init(void)
13754 idr_init(&pmu_idr);
13756 perf_event_init_all_cpus();
13757 init_srcu_struct(&pmus_srcu);
13758 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13759 perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1);
13760 perf_pmu_register(&perf_task_clock, "task_clock", -1);
13761 perf_tp_register();
13762 perf_event_init_cpu(smp_processor_id());
13763 register_reboot_notifier(&perf_reboot_notifier);
13765 ret = init_hw_breakpoint();
13766 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13768 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13771 * Build time assertion that we keep the data_head at the intended
13772 * location. IOW, validation we got the __reserved[] size right.
13774 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13778 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13781 struct perf_pmu_events_attr *pmu_attr =
13782 container_of(attr, struct perf_pmu_events_attr, attr);
13784 if (pmu_attr->event_str)
13785 return sprintf(page, "%s\n", pmu_attr->event_str);
13789 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13791 static int __init perf_event_sysfs_init(void)
13796 mutex_lock(&pmus_lock);
13798 ret = bus_register(&pmu_bus);
13802 list_for_each_entry(pmu, &pmus, entry) {
13806 ret = pmu_dev_alloc(pmu);
13807 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13809 pmu_bus_running = 1;
13813 mutex_unlock(&pmus_lock);
13817 device_initcall(perf_event_sysfs_init);
13819 #ifdef CONFIG_CGROUP_PERF
13820 static struct cgroup_subsys_state *
13821 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13823 struct perf_cgroup *jc;
13825 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13827 return ERR_PTR(-ENOMEM);
13829 jc->info = alloc_percpu(struct perf_cgroup_info);
13832 return ERR_PTR(-ENOMEM);
13838 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13840 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13842 free_percpu(jc->info);
13846 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13848 perf_event_cgroup(css->cgroup);
13852 static int __perf_cgroup_move(void *info)
13854 struct task_struct *task = info;
13857 perf_cgroup_switch(task);
13863 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13865 struct task_struct *task;
13866 struct cgroup_subsys_state *css;
13868 cgroup_taskset_for_each(task, css, tset)
13869 task_function_call(task, __perf_cgroup_move, task);
13872 struct cgroup_subsys perf_event_cgrp_subsys = {
13873 .css_alloc = perf_cgroup_css_alloc,
13874 .css_free = perf_cgroup_css_free,
13875 .css_online = perf_cgroup_css_online,
13876 .attach = perf_cgroup_attach,
13878 * Implicitly enable on dfl hierarchy so that perf events can
13879 * always be filtered by cgroup2 path as long as perf_event
13880 * controller is not mounted on a legacy hierarchy.
13882 .implicit_on_dfl = true,
13885 #endif /* CONFIG_CGROUP_PERF */
13887 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);