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 */
378 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
382 * perf_sched_events : >0 events exist
385 static void perf_sched_delayed(struct work_struct *work);
386 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
387 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
388 static DEFINE_MUTEX(perf_sched_mutex);
389 static atomic_t perf_sched_count;
391 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
393 static atomic_t nr_mmap_events __read_mostly;
394 static atomic_t nr_comm_events __read_mostly;
395 static atomic_t nr_namespaces_events __read_mostly;
396 static atomic_t nr_task_events __read_mostly;
397 static atomic_t nr_freq_events __read_mostly;
398 static atomic_t nr_switch_events __read_mostly;
399 static atomic_t nr_ksymbol_events __read_mostly;
400 static atomic_t nr_bpf_events __read_mostly;
401 static atomic_t nr_cgroup_events __read_mostly;
402 static atomic_t nr_text_poke_events __read_mostly;
403 static atomic_t nr_build_id_events __read_mostly;
405 static LIST_HEAD(pmus);
406 static DEFINE_MUTEX(pmus_lock);
407 static struct srcu_struct pmus_srcu;
408 static cpumask_var_t perf_online_mask;
409 static struct kmem_cache *perf_event_cache;
412 * perf event paranoia level:
413 * -1 - not paranoid at all
414 * 0 - disallow raw tracepoint access for unpriv
415 * 1 - disallow cpu events for unpriv
416 * 2 - disallow kernel profiling for unpriv
418 int sysctl_perf_event_paranoid __read_mostly = 2;
420 /* Minimum for 512 kiB + 1 user control page */
421 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
424 * max perf event sample rate
426 #define DEFAULT_MAX_SAMPLE_RATE 100000
427 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
428 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
430 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
432 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
433 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
435 static int perf_sample_allowed_ns __read_mostly =
436 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
438 static void update_perf_cpu_limits(void)
440 u64 tmp = perf_sample_period_ns;
442 tmp *= sysctl_perf_cpu_time_max_percent;
443 tmp = div_u64(tmp, 100);
447 WRITE_ONCE(perf_sample_allowed_ns, tmp);
450 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc);
452 int perf_proc_update_handler(struct ctl_table *table, int write,
453 void *buffer, size_t *lenp, loff_t *ppos)
456 int perf_cpu = sysctl_perf_cpu_time_max_percent;
458 * If throttling is disabled don't allow the write:
460 if (write && (perf_cpu == 100 || perf_cpu == 0))
463 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
467 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
468 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 update_perf_cpu_limits();
474 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
476 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
477 void *buffer, size_t *lenp, loff_t *ppos)
479 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
484 if (sysctl_perf_cpu_time_max_percent == 100 ||
485 sysctl_perf_cpu_time_max_percent == 0) {
487 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
488 WRITE_ONCE(perf_sample_allowed_ns, 0);
490 update_perf_cpu_limits();
497 * perf samples are done in some very critical code paths (NMIs).
498 * If they take too much CPU time, the system can lock up and not
499 * get any real work done. This will drop the sample rate when
500 * we detect that events are taking too long.
502 #define NR_ACCUMULATED_SAMPLES 128
503 static DEFINE_PER_CPU(u64, running_sample_length);
505 static u64 __report_avg;
506 static u64 __report_allowed;
508 static void perf_duration_warn(struct irq_work *w)
510 printk_ratelimited(KERN_INFO
511 "perf: interrupt took too long (%lld > %lld), lowering "
512 "kernel.perf_event_max_sample_rate to %d\n",
513 __report_avg, __report_allowed,
514 sysctl_perf_event_sample_rate);
517 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
519 void perf_sample_event_took(u64 sample_len_ns)
521 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
529 /* Decay the counter by 1 average sample. */
530 running_len = __this_cpu_read(running_sample_length);
531 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
532 running_len += sample_len_ns;
533 __this_cpu_write(running_sample_length, running_len);
536 * Note: this will be biased artifically low until we have
537 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
538 * from having to maintain a count.
540 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
541 if (avg_len <= max_len)
544 __report_avg = avg_len;
545 __report_allowed = max_len;
548 * Compute a throttle threshold 25% below the current duration.
550 avg_len += avg_len / 4;
551 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
557 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
558 WRITE_ONCE(max_samples_per_tick, max);
560 sysctl_perf_event_sample_rate = max * HZ;
561 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
563 if (!irq_work_queue(&perf_duration_work)) {
564 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
565 "kernel.perf_event_max_sample_rate to %d\n",
566 __report_avg, __report_allowed,
567 sysctl_perf_event_sample_rate);
571 static atomic64_t perf_event_id;
573 static void update_context_time(struct perf_event_context *ctx);
574 static u64 perf_event_time(struct perf_event *event);
576 void __weak perf_event_print_debug(void) { }
578 static inline u64 perf_clock(void)
580 return local_clock();
583 static inline u64 perf_event_clock(struct perf_event *event)
585 return event->clock();
589 * State based event timekeeping...
591 * The basic idea is to use event->state to determine which (if any) time
592 * fields to increment with the current delta. This means we only need to
593 * update timestamps when we change state or when they are explicitly requested
596 * Event groups make things a little more complicated, but not terribly so. The
597 * rules for a group are that if the group leader is OFF the entire group is
598 * OFF, irrespecive of what the group member states are. This results in
599 * __perf_effective_state().
601 * A futher ramification is that when a group leader flips between OFF and
602 * !OFF, we need to update all group member times.
605 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
606 * need to make sure the relevant context time is updated before we try and
607 * update our timestamps.
610 static __always_inline enum perf_event_state
611 __perf_effective_state(struct perf_event *event)
613 struct perf_event *leader = event->group_leader;
615 if (leader->state <= PERF_EVENT_STATE_OFF)
616 return leader->state;
621 static __always_inline void
622 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
624 enum perf_event_state state = __perf_effective_state(event);
625 u64 delta = now - event->tstamp;
627 *enabled = event->total_time_enabled;
628 if (state >= PERF_EVENT_STATE_INACTIVE)
631 *running = event->total_time_running;
632 if (state >= PERF_EVENT_STATE_ACTIVE)
636 static void perf_event_update_time(struct perf_event *event)
638 u64 now = perf_event_time(event);
640 __perf_update_times(event, now, &event->total_time_enabled,
641 &event->total_time_running);
645 static void perf_event_update_sibling_time(struct perf_event *leader)
647 struct perf_event *sibling;
649 for_each_sibling_event(sibling, leader)
650 perf_event_update_time(sibling);
654 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
656 if (event->state == state)
659 perf_event_update_time(event);
661 * If a group leader gets enabled/disabled all its siblings
664 if ((event->state < 0) ^ (state < 0))
665 perf_event_update_sibling_time(event);
667 WRITE_ONCE(event->state, state);
671 * UP store-release, load-acquire
674 #define __store_release(ptr, val) \
677 WRITE_ONCE(*(ptr), (val)); \
680 #define __load_acquire(ptr) \
682 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \
687 static void perf_ctx_disable(struct perf_event_context *ctx)
689 struct perf_event_pmu_context *pmu_ctx;
691 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
692 perf_pmu_disable(pmu_ctx->pmu);
695 static void perf_ctx_enable(struct perf_event_context *ctx)
697 struct perf_event_pmu_context *pmu_ctx;
699 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
700 perf_pmu_enable(pmu_ctx->pmu);
703 static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type);
704 static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type);
706 #ifdef CONFIG_CGROUP_PERF
709 perf_cgroup_match(struct perf_event *event)
711 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
713 /* @event doesn't care about cgroup */
717 /* wants specific cgroup scope but @cpuctx isn't associated with any */
722 * Cgroup scoping is recursive. An event enabled for a cgroup is
723 * also enabled for all its descendant cgroups. If @cpuctx's
724 * cgroup is a descendant of @event's (the test covers identity
725 * case), it's a match.
727 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
728 event->cgrp->css.cgroup);
731 static inline void perf_detach_cgroup(struct perf_event *event)
733 css_put(&event->cgrp->css);
737 static inline int is_cgroup_event(struct perf_event *event)
739 return event->cgrp != NULL;
742 static inline u64 perf_cgroup_event_time(struct perf_event *event)
744 struct perf_cgroup_info *t;
746 t = per_cpu_ptr(event->cgrp->info, event->cpu);
750 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
752 struct perf_cgroup_info *t;
754 t = per_cpu_ptr(event->cgrp->info, event->cpu);
755 if (!__load_acquire(&t->active))
757 now += READ_ONCE(t->timeoffset);
761 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv)
764 info->time += now - info->timestamp;
765 info->timestamp = now;
767 * see update_context_time()
769 WRITE_ONCE(info->timeoffset, info->time - info->timestamp);
772 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final)
774 struct perf_cgroup *cgrp = cpuctx->cgrp;
775 struct cgroup_subsys_state *css;
776 struct perf_cgroup_info *info;
779 u64 now = perf_clock();
781 for (css = &cgrp->css; css; css = css->parent) {
782 cgrp = container_of(css, struct perf_cgroup, css);
783 info = this_cpu_ptr(cgrp->info);
785 __update_cgrp_time(info, now, true);
787 __store_release(&info->active, 0);
792 static inline void update_cgrp_time_from_event(struct perf_event *event)
794 struct perf_cgroup_info *info;
797 * ensure we access cgroup data only when needed and
798 * when we know the cgroup is pinned (css_get)
800 if (!is_cgroup_event(event))
803 info = this_cpu_ptr(event->cgrp->info);
805 * Do not update time when cgroup is not active
808 __update_cgrp_time(info, perf_clock(), true);
812 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
814 struct perf_event_context *ctx = &cpuctx->ctx;
815 struct perf_cgroup *cgrp = cpuctx->cgrp;
816 struct perf_cgroup_info *info;
817 struct cgroup_subsys_state *css;
820 * ctx->lock held by caller
821 * ensure we do not access cgroup data
822 * unless we have the cgroup pinned (css_get)
827 WARN_ON_ONCE(!ctx->nr_cgroups);
829 for (css = &cgrp->css; css; css = css->parent) {
830 cgrp = container_of(css, struct perf_cgroup, css);
831 info = this_cpu_ptr(cgrp->info);
832 __update_cgrp_time(info, ctx->timestamp, false);
833 __store_release(&info->active, 1);
838 * reschedule events based on the cgroup constraint of task.
840 static void perf_cgroup_switch(struct task_struct *task)
842 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
843 struct perf_cgroup *cgrp;
846 * cpuctx->cgrp is set when the first cgroup event enabled,
847 * and is cleared when the last cgroup event disabled.
849 if (READ_ONCE(cpuctx->cgrp) == NULL)
852 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
854 cgrp = perf_cgroup_from_task(task, NULL);
855 if (READ_ONCE(cpuctx->cgrp) == cgrp)
858 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
859 perf_ctx_disable(&cpuctx->ctx);
861 ctx_sched_out(&cpuctx->ctx, EVENT_ALL);
863 * must not be done before ctxswout due
864 * to update_cgrp_time_from_cpuctx() in
869 * set cgrp before ctxsw in to allow
870 * perf_cgroup_set_timestamp() in ctx_sched_in()
871 * to not have to pass task around
873 ctx_sched_in(&cpuctx->ctx, EVENT_ALL);
875 perf_ctx_enable(&cpuctx->ctx);
876 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
879 static int perf_cgroup_ensure_storage(struct perf_event *event,
880 struct cgroup_subsys_state *css)
882 struct perf_cpu_context *cpuctx;
883 struct perf_event **storage;
884 int cpu, heap_size, ret = 0;
887 * Allow storage to have sufficent space for an iterator for each
888 * possibly nested cgroup plus an iterator for events with no cgroup.
890 for (heap_size = 1; css; css = css->parent)
893 for_each_possible_cpu(cpu) {
894 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
895 if (heap_size <= cpuctx->heap_size)
898 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
899 GFP_KERNEL, cpu_to_node(cpu));
905 raw_spin_lock_irq(&cpuctx->ctx.lock);
906 if (cpuctx->heap_size < heap_size) {
907 swap(cpuctx->heap, storage);
908 if (storage == cpuctx->heap_default)
910 cpuctx->heap_size = heap_size;
912 raw_spin_unlock_irq(&cpuctx->ctx.lock);
920 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
921 struct perf_event_attr *attr,
922 struct perf_event *group_leader)
924 struct perf_cgroup *cgrp;
925 struct cgroup_subsys_state *css;
926 struct fd f = fdget(fd);
932 css = css_tryget_online_from_dir(f.file->f_path.dentry,
933 &perf_event_cgrp_subsys);
939 ret = perf_cgroup_ensure_storage(event, css);
943 cgrp = container_of(css, struct perf_cgroup, css);
947 * all events in a group must monitor
948 * the same cgroup because a task belongs
949 * to only one perf cgroup at a time
951 if (group_leader && group_leader->cgrp != cgrp) {
952 perf_detach_cgroup(event);
961 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
963 struct perf_cpu_context *cpuctx;
965 if (!is_cgroup_event(event))
969 * Because cgroup events are always per-cpu events,
970 * @ctx == &cpuctx->ctx.
972 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
974 if (ctx->nr_cgroups++)
977 cpuctx->cgrp = perf_cgroup_from_task(current, ctx);
981 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
983 struct perf_cpu_context *cpuctx;
985 if (!is_cgroup_event(event))
989 * Because cgroup events are always per-cpu events,
990 * @ctx == &cpuctx->ctx.
992 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
994 if (--ctx->nr_cgroups)
1000 #else /* !CONFIG_CGROUP_PERF */
1003 perf_cgroup_match(struct perf_event *event)
1008 static inline void perf_detach_cgroup(struct perf_event *event)
1011 static inline int is_cgroup_event(struct perf_event *event)
1016 static inline void update_cgrp_time_from_event(struct perf_event *event)
1020 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx,
1025 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1026 struct perf_event_attr *attr,
1027 struct perf_event *group_leader)
1033 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx)
1037 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1042 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now)
1048 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1053 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1057 static void perf_cgroup_switch(struct task_struct *task)
1063 * set default to be dependent on timer tick just
1064 * like original code
1066 #define PERF_CPU_HRTIMER (1000 / HZ)
1068 * function must be called with interrupts disabled
1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1072 struct perf_cpu_pmu_context *cpc;
1075 lockdep_assert_irqs_disabled();
1077 cpc = container_of(hr, struct perf_cpu_pmu_context, hrtimer);
1078 rotations = perf_rotate_context(cpc);
1080 raw_spin_lock(&cpc->hrtimer_lock);
1082 hrtimer_forward_now(hr, cpc->hrtimer_interval);
1084 cpc->hrtimer_active = 0;
1085 raw_spin_unlock(&cpc->hrtimer_lock);
1087 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1090 static void __perf_mux_hrtimer_init(struct perf_cpu_pmu_context *cpc, int cpu)
1092 struct hrtimer *timer = &cpc->hrtimer;
1093 struct pmu *pmu = cpc->epc.pmu;
1097 * check default is sane, if not set then force to
1098 * default interval (1/tick)
1100 interval = pmu->hrtimer_interval_ms;
1102 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1104 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1106 raw_spin_lock_init(&cpc->hrtimer_lock);
1107 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1108 timer->function = perf_mux_hrtimer_handler;
1111 static int perf_mux_hrtimer_restart(struct perf_cpu_pmu_context *cpc)
1113 struct hrtimer *timer = &cpc->hrtimer;
1114 unsigned long flags;
1116 raw_spin_lock_irqsave(&cpc->hrtimer_lock, flags);
1117 if (!cpc->hrtimer_active) {
1118 cpc->hrtimer_active = 1;
1119 hrtimer_forward_now(timer, cpc->hrtimer_interval);
1120 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1122 raw_spin_unlock_irqrestore(&cpc->hrtimer_lock, flags);
1127 static int perf_mux_hrtimer_restart_ipi(void *arg)
1129 return perf_mux_hrtimer_restart(arg);
1132 void perf_pmu_disable(struct pmu *pmu)
1134 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1136 pmu->pmu_disable(pmu);
1139 void perf_pmu_enable(struct pmu *pmu)
1141 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1143 pmu->pmu_enable(pmu);
1146 static void perf_assert_pmu_disabled(struct pmu *pmu)
1148 WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0);
1151 static void get_ctx(struct perf_event_context *ctx)
1153 refcount_inc(&ctx->refcount);
1156 static void *alloc_task_ctx_data(struct pmu *pmu)
1158 if (pmu->task_ctx_cache)
1159 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1164 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1166 if (pmu->task_ctx_cache && task_ctx_data)
1167 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1170 static void free_ctx(struct rcu_head *head)
1172 struct perf_event_context *ctx;
1174 ctx = container_of(head, struct perf_event_context, rcu_head);
1178 static void put_ctx(struct perf_event_context *ctx)
1180 if (refcount_dec_and_test(&ctx->refcount)) {
1181 if (ctx->parent_ctx)
1182 put_ctx(ctx->parent_ctx);
1183 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1184 put_task_struct(ctx->task);
1185 call_rcu(&ctx->rcu_head, free_ctx);
1190 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1191 * perf_pmu_migrate_context() we need some magic.
1193 * Those places that change perf_event::ctx will hold both
1194 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1196 * Lock ordering is by mutex address. There are two other sites where
1197 * perf_event_context::mutex nests and those are:
1199 * - perf_event_exit_task_context() [ child , 0 ]
1200 * perf_event_exit_event()
1201 * put_event() [ parent, 1 ]
1203 * - perf_event_init_context() [ parent, 0 ]
1204 * inherit_task_group()
1207 * perf_event_alloc()
1209 * perf_try_init_event() [ child , 1 ]
1211 * While it appears there is an obvious deadlock here -- the parent and child
1212 * nesting levels are inverted between the two. This is in fact safe because
1213 * life-time rules separate them. That is an exiting task cannot fork, and a
1214 * spawning task cannot (yet) exit.
1216 * But remember that these are parent<->child context relations, and
1217 * migration does not affect children, therefore these two orderings should not
1220 * The change in perf_event::ctx does not affect children (as claimed above)
1221 * because the sys_perf_event_open() case will install a new event and break
1222 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1223 * concerned with cpuctx and that doesn't have children.
1225 * The places that change perf_event::ctx will issue:
1227 * perf_remove_from_context();
1228 * synchronize_rcu();
1229 * perf_install_in_context();
1231 * to affect the change. The remove_from_context() + synchronize_rcu() should
1232 * quiesce the event, after which we can install it in the new location. This
1233 * means that only external vectors (perf_fops, prctl) can perturb the event
1234 * while in transit. Therefore all such accessors should also acquire
1235 * perf_event_context::mutex to serialize against this.
1237 * However; because event->ctx can change while we're waiting to acquire
1238 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1243 * task_struct::perf_event_mutex
1244 * perf_event_context::mutex
1245 * perf_event::child_mutex;
1246 * perf_event_context::lock
1247 * perf_event::mmap_mutex
1249 * perf_addr_filters_head::lock
1253 * cpuctx->mutex / perf_event_context::mutex
1255 static struct perf_event_context *
1256 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1258 struct perf_event_context *ctx;
1262 ctx = READ_ONCE(event->ctx);
1263 if (!refcount_inc_not_zero(&ctx->refcount)) {
1269 mutex_lock_nested(&ctx->mutex, nesting);
1270 if (event->ctx != ctx) {
1271 mutex_unlock(&ctx->mutex);
1279 static inline struct perf_event_context *
1280 perf_event_ctx_lock(struct perf_event *event)
1282 return perf_event_ctx_lock_nested(event, 0);
1285 static void perf_event_ctx_unlock(struct perf_event *event,
1286 struct perf_event_context *ctx)
1288 mutex_unlock(&ctx->mutex);
1293 * This must be done under the ctx->lock, such as to serialize against
1294 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1295 * calling scheduler related locks and ctx->lock nests inside those.
1297 static __must_check struct perf_event_context *
1298 unclone_ctx(struct perf_event_context *ctx)
1300 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1302 lockdep_assert_held(&ctx->lock);
1305 ctx->parent_ctx = NULL;
1311 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1316 * only top level events have the pid namespace they were created in
1319 event = event->parent;
1321 nr = __task_pid_nr_ns(p, type, event->ns);
1322 /* avoid -1 if it is idle thread or runs in another ns */
1323 if (!nr && !pid_alive(p))
1328 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1330 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1333 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1335 return perf_event_pid_type(event, p, PIDTYPE_PID);
1339 * If we inherit events we want to return the parent event id
1342 static u64 primary_event_id(struct perf_event *event)
1347 id = event->parent->id;
1353 * Get the perf_event_context for a task and lock it.
1355 * This has to cope with the fact that until it is locked,
1356 * the context could get moved to another task.
1358 static struct perf_event_context *
1359 perf_lock_task_context(struct task_struct *task, unsigned long *flags)
1361 struct perf_event_context *ctx;
1365 * One of the few rules of preemptible RCU is that one cannot do
1366 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1367 * part of the read side critical section was irqs-enabled -- see
1368 * rcu_read_unlock_special().
1370 * Since ctx->lock nests under rq->lock we must ensure the entire read
1371 * side critical section has interrupts disabled.
1373 local_irq_save(*flags);
1375 ctx = rcu_dereference(task->perf_event_ctxp);
1378 * If this context is a clone of another, it might
1379 * get swapped for another underneath us by
1380 * perf_event_task_sched_out, though the
1381 * rcu_read_lock() protects us from any context
1382 * getting freed. Lock the context and check if it
1383 * got swapped before we could get the lock, and retry
1384 * if so. If we locked the right context, then it
1385 * can't get swapped on us any more.
1387 raw_spin_lock(&ctx->lock);
1388 if (ctx != rcu_dereference(task->perf_event_ctxp)) {
1389 raw_spin_unlock(&ctx->lock);
1391 local_irq_restore(*flags);
1395 if (ctx->task == TASK_TOMBSTONE ||
1396 !refcount_inc_not_zero(&ctx->refcount)) {
1397 raw_spin_unlock(&ctx->lock);
1400 WARN_ON_ONCE(ctx->task != task);
1405 local_irq_restore(*flags);
1410 * Get the context for a task and increment its pin_count so it
1411 * can't get swapped to another task. This also increments its
1412 * reference count so that the context can't get freed.
1414 static struct perf_event_context *
1415 perf_pin_task_context(struct task_struct *task)
1417 struct perf_event_context *ctx;
1418 unsigned long flags;
1420 ctx = perf_lock_task_context(task, &flags);
1423 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1428 static void perf_unpin_context(struct perf_event_context *ctx)
1430 unsigned long flags;
1432 raw_spin_lock_irqsave(&ctx->lock, flags);
1434 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1438 * Update the record of the current time in a context.
1440 static void __update_context_time(struct perf_event_context *ctx, bool adv)
1442 u64 now = perf_clock();
1444 lockdep_assert_held(&ctx->lock);
1447 ctx->time += now - ctx->timestamp;
1448 ctx->timestamp = now;
1451 * The above: time' = time + (now - timestamp), can be re-arranged
1452 * into: time` = now + (time - timestamp), which gives a single value
1453 * offset to compute future time without locks on.
1455 * See perf_event_time_now(), which can be used from NMI context where
1456 * it's (obviously) not possible to acquire ctx->lock in order to read
1457 * both the above values in a consistent manner.
1459 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp);
1462 static void update_context_time(struct perf_event_context *ctx)
1464 __update_context_time(ctx, true);
1467 static u64 perf_event_time(struct perf_event *event)
1469 struct perf_event_context *ctx = event->ctx;
1474 if (is_cgroup_event(event))
1475 return perf_cgroup_event_time(event);
1480 static u64 perf_event_time_now(struct perf_event *event, u64 now)
1482 struct perf_event_context *ctx = event->ctx;
1487 if (is_cgroup_event(event))
1488 return perf_cgroup_event_time_now(event, now);
1490 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME))
1493 now += READ_ONCE(ctx->timeoffset);
1497 static enum event_type_t get_event_type(struct perf_event *event)
1499 struct perf_event_context *ctx = event->ctx;
1500 enum event_type_t event_type;
1502 lockdep_assert_held(&ctx->lock);
1505 * It's 'group type', really, because if our group leader is
1506 * pinned, so are we.
1508 if (event->group_leader != event)
1509 event = event->group_leader;
1511 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1513 event_type |= EVENT_CPU;
1519 * Helper function to initialize event group nodes.
1521 static void init_event_group(struct perf_event *event)
1523 RB_CLEAR_NODE(&event->group_node);
1524 event->group_index = 0;
1528 * Extract pinned or flexible groups from the context
1529 * based on event attrs bits.
1531 static struct perf_event_groups *
1532 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1534 if (event->attr.pinned)
1535 return &ctx->pinned_groups;
1537 return &ctx->flexible_groups;
1541 * Helper function to initializes perf_event_group trees.
1543 static void perf_event_groups_init(struct perf_event_groups *groups)
1545 groups->tree = RB_ROOT;
1549 static inline struct cgroup *event_cgroup(const struct perf_event *event)
1551 struct cgroup *cgroup = NULL;
1553 #ifdef CONFIG_CGROUP_PERF
1555 cgroup = event->cgrp->css.cgroup;
1562 * Compare function for event groups;
1564 * Implements complex key that first sorts by CPU and then by virtual index
1565 * which provides ordering when rotating groups for the same CPU.
1567 static __always_inline int
1568 perf_event_groups_cmp(const int left_cpu, const struct pmu *left_pmu,
1569 const struct cgroup *left_cgroup, const u64 left_group_index,
1570 const struct perf_event *right)
1572 if (left_cpu < right->cpu)
1574 if (left_cpu > right->cpu)
1578 if (left_pmu < right->pmu_ctx->pmu)
1580 if (left_pmu > right->pmu_ctx->pmu)
1584 #ifdef CONFIG_CGROUP_PERF
1586 const struct cgroup *right_cgroup = event_cgroup(right);
1588 if (left_cgroup != right_cgroup) {
1591 * Left has no cgroup but right does, no
1592 * cgroups come first.
1596 if (!right_cgroup) {
1598 * Right has no cgroup but left does, no
1599 * cgroups come first.
1603 /* Two dissimilar cgroups, order by id. */
1604 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1612 if (left_group_index < right->group_index)
1614 if (left_group_index > right->group_index)
1620 #define __node_2_pe(node) \
1621 rb_entry((node), struct perf_event, group_node)
1623 static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1625 struct perf_event *e = __node_2_pe(a);
1626 return perf_event_groups_cmp(e->cpu, e->pmu_ctx->pmu, event_cgroup(e),
1627 e->group_index, __node_2_pe(b)) < 0;
1630 struct __group_key {
1633 struct cgroup *cgroup;
1636 static inline int __group_cmp(const void *key, const struct rb_node *node)
1638 const struct __group_key *a = key;
1639 const struct perf_event *b = __node_2_pe(node);
1641 /* partial/subtree match: @cpu, @pmu, @cgroup; ignore: @group_index */
1642 return perf_event_groups_cmp(a->cpu, a->pmu, a->cgroup, b->group_index, b);
1646 __group_cmp_ignore_cgroup(const void *key, const struct rb_node *node)
1648 const struct __group_key *a = key;
1649 const struct perf_event *b = __node_2_pe(node);
1651 /* partial/subtree match: @cpu, @pmu, ignore: @cgroup, @group_index */
1652 return perf_event_groups_cmp(a->cpu, a->pmu, event_cgroup(b),
1657 * Insert @event into @groups' tree; using
1658 * {@event->cpu, @event->pmu_ctx->pmu, event_cgroup(@event), ++@groups->index}
1659 * as key. This places it last inside the {cpu,pmu,cgroup} subtree.
1662 perf_event_groups_insert(struct perf_event_groups *groups,
1663 struct perf_event *event)
1665 event->group_index = ++groups->index;
1667 rb_add(&event->group_node, &groups->tree, __group_less);
1671 * Helper function to insert event into the pinned or flexible groups.
1674 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1676 struct perf_event_groups *groups;
1678 groups = get_event_groups(event, ctx);
1679 perf_event_groups_insert(groups, event);
1683 * Delete a group from a tree.
1686 perf_event_groups_delete(struct perf_event_groups *groups,
1687 struct perf_event *event)
1689 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1690 RB_EMPTY_ROOT(&groups->tree));
1692 rb_erase(&event->group_node, &groups->tree);
1693 init_event_group(event);
1697 * Helper function to delete event from its groups.
1700 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1702 struct perf_event_groups *groups;
1704 groups = get_event_groups(event, ctx);
1705 perf_event_groups_delete(groups, event);
1709 * Get the leftmost event in the {cpu,pmu,cgroup} subtree.
1711 static struct perf_event *
1712 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1713 struct pmu *pmu, struct cgroup *cgrp)
1715 struct __group_key key = {
1720 struct rb_node *node;
1722 node = rb_find_first(&key, &groups->tree, __group_cmp);
1724 return __node_2_pe(node);
1729 static struct perf_event *
1730 perf_event_groups_next(struct perf_event *event, struct pmu *pmu)
1732 struct __group_key key = {
1735 .cgroup = event_cgroup(event),
1737 struct rb_node *next;
1739 next = rb_next_match(&key, &event->group_node, __group_cmp);
1741 return __node_2_pe(next);
1746 #define perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) \
1747 for (event = perf_event_groups_first(groups, cpu, pmu, NULL); \
1748 event; event = perf_event_groups_next(event, pmu))
1751 * Iterate through the whole groups tree.
1753 #define perf_event_groups_for_each(event, groups) \
1754 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1755 typeof(*event), group_node); event; \
1756 event = rb_entry_safe(rb_next(&event->group_node), \
1757 typeof(*event), group_node))
1760 * Add an event from the lists for its context.
1761 * Must be called with ctx->mutex and ctx->lock held.
1764 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1766 lockdep_assert_held(&ctx->lock);
1768 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1769 event->attach_state |= PERF_ATTACH_CONTEXT;
1771 event->tstamp = perf_event_time(event);
1774 * If we're a stand alone event or group leader, we go to the context
1775 * list, group events are kept attached to the group so that
1776 * perf_group_detach can, at all times, locate all siblings.
1778 if (event->group_leader == event) {
1779 event->group_caps = event->event_caps;
1780 add_event_to_groups(event, ctx);
1783 list_add_rcu(&event->event_entry, &ctx->event_list);
1785 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1787 if (event->attr.inherit_stat)
1790 if (event->state > PERF_EVENT_STATE_OFF)
1791 perf_cgroup_event_enable(event, ctx);
1794 event->pmu_ctx->nr_events++;
1798 * Initialize event state based on the perf_event_attr::disabled.
1800 static inline void perf_event__state_init(struct perf_event *event)
1802 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1803 PERF_EVENT_STATE_INACTIVE;
1806 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1808 int entry = sizeof(u64); /* value */
1812 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1813 size += sizeof(u64);
1815 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1816 size += sizeof(u64);
1818 if (event->attr.read_format & PERF_FORMAT_ID)
1819 entry += sizeof(u64);
1821 if (event->attr.read_format & PERF_FORMAT_LOST)
1822 entry += sizeof(u64);
1824 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1826 size += sizeof(u64);
1830 event->read_size = size;
1833 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1835 struct perf_sample_data *data;
1838 if (sample_type & PERF_SAMPLE_IP)
1839 size += sizeof(data->ip);
1841 if (sample_type & PERF_SAMPLE_ADDR)
1842 size += sizeof(data->addr);
1844 if (sample_type & PERF_SAMPLE_PERIOD)
1845 size += sizeof(data->period);
1847 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1848 size += sizeof(data->weight.full);
1850 if (sample_type & PERF_SAMPLE_READ)
1851 size += event->read_size;
1853 if (sample_type & PERF_SAMPLE_DATA_SRC)
1854 size += sizeof(data->data_src.val);
1856 if (sample_type & PERF_SAMPLE_TRANSACTION)
1857 size += sizeof(data->txn);
1859 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1860 size += sizeof(data->phys_addr);
1862 if (sample_type & PERF_SAMPLE_CGROUP)
1863 size += sizeof(data->cgroup);
1865 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1866 size += sizeof(data->data_page_size);
1868 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1869 size += sizeof(data->code_page_size);
1871 event->header_size = size;
1875 * Called at perf_event creation and when events are attached/detached from a
1878 static void perf_event__header_size(struct perf_event *event)
1880 __perf_event_read_size(event,
1881 event->group_leader->nr_siblings);
1882 __perf_event_header_size(event, event->attr.sample_type);
1885 static void perf_event__id_header_size(struct perf_event *event)
1887 struct perf_sample_data *data;
1888 u64 sample_type = event->attr.sample_type;
1891 if (sample_type & PERF_SAMPLE_TID)
1892 size += sizeof(data->tid_entry);
1894 if (sample_type & PERF_SAMPLE_TIME)
1895 size += sizeof(data->time);
1897 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1898 size += sizeof(data->id);
1900 if (sample_type & PERF_SAMPLE_ID)
1901 size += sizeof(data->id);
1903 if (sample_type & PERF_SAMPLE_STREAM_ID)
1904 size += sizeof(data->stream_id);
1906 if (sample_type & PERF_SAMPLE_CPU)
1907 size += sizeof(data->cpu_entry);
1909 event->id_header_size = size;
1912 static bool perf_event_validate_size(struct perf_event *event)
1915 * The values computed here will be over-written when we actually
1918 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1919 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1920 perf_event__id_header_size(event);
1923 * Sum the lot; should not exceed the 64k limit we have on records.
1924 * Conservative limit to allow for callchains and other variable fields.
1926 if (event->read_size + event->header_size +
1927 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1933 static void perf_group_attach(struct perf_event *event)
1935 struct perf_event *group_leader = event->group_leader, *pos;
1937 lockdep_assert_held(&event->ctx->lock);
1940 * We can have double attach due to group movement (move_group) in
1941 * perf_event_open().
1943 if (event->attach_state & PERF_ATTACH_GROUP)
1946 event->attach_state |= PERF_ATTACH_GROUP;
1948 if (group_leader == event)
1951 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1953 group_leader->group_caps &= event->event_caps;
1955 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1956 group_leader->nr_siblings++;
1958 perf_event__header_size(group_leader);
1960 for_each_sibling_event(pos, group_leader)
1961 perf_event__header_size(pos);
1965 * Remove an event from the lists for its context.
1966 * Must be called with ctx->mutex and ctx->lock held.
1969 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1971 WARN_ON_ONCE(event->ctx != ctx);
1972 lockdep_assert_held(&ctx->lock);
1975 * We can have double detach due to exit/hot-unplug + close.
1977 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1980 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1983 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1985 if (event->attr.inherit_stat)
1988 list_del_rcu(&event->event_entry);
1990 if (event->group_leader == event)
1991 del_event_from_groups(event, ctx);
1994 * If event was in error state, then keep it
1995 * that way, otherwise bogus counts will be
1996 * returned on read(). The only way to get out
1997 * of error state is by explicit re-enabling
2000 if (event->state > PERF_EVENT_STATE_OFF) {
2001 perf_cgroup_event_disable(event, ctx);
2002 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2006 event->pmu_ctx->nr_events--;
2010 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2012 if (!has_aux(aux_event))
2015 if (!event->pmu->aux_output_match)
2018 return event->pmu->aux_output_match(aux_event);
2021 static void put_event(struct perf_event *event);
2022 static void event_sched_out(struct perf_event *event,
2023 struct perf_event_context *ctx);
2025 static void perf_put_aux_event(struct perf_event *event)
2027 struct perf_event_context *ctx = event->ctx;
2028 struct perf_event *iter;
2031 * If event uses aux_event tear down the link
2033 if (event->aux_event) {
2034 iter = event->aux_event;
2035 event->aux_event = NULL;
2041 * If the event is an aux_event, tear down all links to
2042 * it from other events.
2044 for_each_sibling_event(iter, event->group_leader) {
2045 if (iter->aux_event != event)
2048 iter->aux_event = NULL;
2052 * If it's ACTIVE, schedule it out and put it into ERROR
2053 * state so that we don't try to schedule it again. Note
2054 * that perf_event_enable() will clear the ERROR status.
2056 event_sched_out(iter, ctx);
2057 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2061 static bool perf_need_aux_event(struct perf_event *event)
2063 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2066 static int perf_get_aux_event(struct perf_event *event,
2067 struct perf_event *group_leader)
2070 * Our group leader must be an aux event if we want to be
2071 * an aux_output. This way, the aux event will precede its
2072 * aux_output events in the group, and therefore will always
2079 * aux_output and aux_sample_size are mutually exclusive.
2081 if (event->attr.aux_output && event->attr.aux_sample_size)
2084 if (event->attr.aux_output &&
2085 !perf_aux_output_match(event, group_leader))
2088 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2091 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2095 * Link aux_outputs to their aux event; this is undone in
2096 * perf_group_detach() by perf_put_aux_event(). When the
2097 * group in torn down, the aux_output events loose their
2098 * link to the aux_event and can't schedule any more.
2100 event->aux_event = group_leader;
2105 static inline struct list_head *get_event_list(struct perf_event *event)
2107 return event->attr.pinned ? &event->pmu_ctx->pinned_active :
2108 &event->pmu_ctx->flexible_active;
2112 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2113 * cannot exist on their own, schedule them out and move them into the ERROR
2114 * state. Also see _perf_event_enable(), it will not be able to recover
2117 static inline void perf_remove_sibling_event(struct perf_event *event)
2119 event_sched_out(event, event->ctx);
2120 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2123 static void perf_group_detach(struct perf_event *event)
2125 struct perf_event *leader = event->group_leader;
2126 struct perf_event *sibling, *tmp;
2127 struct perf_event_context *ctx = event->ctx;
2129 lockdep_assert_held(&ctx->lock);
2132 * We can have double detach due to exit/hot-unplug + close.
2134 if (!(event->attach_state & PERF_ATTACH_GROUP))
2137 event->attach_state &= ~PERF_ATTACH_GROUP;
2139 perf_put_aux_event(event);
2142 * If this is a sibling, remove it from its group.
2144 if (leader != event) {
2145 list_del_init(&event->sibling_list);
2146 event->group_leader->nr_siblings--;
2151 * If this was a group event with sibling events then
2152 * upgrade the siblings to singleton events by adding them
2153 * to whatever list we are on.
2155 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2157 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2158 perf_remove_sibling_event(sibling);
2160 sibling->group_leader = sibling;
2161 list_del_init(&sibling->sibling_list);
2163 /* Inherit group flags from the previous leader */
2164 sibling->group_caps = event->group_caps;
2166 if (sibling->attach_state & PERF_ATTACH_CONTEXT) {
2167 add_event_to_groups(sibling, event->ctx);
2169 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2170 list_add_tail(&sibling->active_list, get_event_list(sibling));
2173 WARN_ON_ONCE(sibling->ctx != event->ctx);
2177 for_each_sibling_event(tmp, leader)
2178 perf_event__header_size(tmp);
2180 perf_event__header_size(leader);
2183 static void sync_child_event(struct perf_event *child_event);
2185 static void perf_child_detach(struct perf_event *event)
2187 struct perf_event *parent_event = event->parent;
2189 if (!(event->attach_state & PERF_ATTACH_CHILD))
2192 event->attach_state &= ~PERF_ATTACH_CHILD;
2194 if (WARN_ON_ONCE(!parent_event))
2197 lockdep_assert_held(&parent_event->child_mutex);
2199 sync_child_event(event);
2200 list_del_init(&event->child_list);
2203 static bool is_orphaned_event(struct perf_event *event)
2205 return event->state == PERF_EVENT_STATE_DEAD;
2209 event_filter_match(struct perf_event *event)
2211 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2212 perf_cgroup_match(event);
2216 event_sched_out(struct perf_event *event, struct perf_event_context *ctx)
2218 struct perf_event_pmu_context *epc = event->pmu_ctx;
2219 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2220 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2222 // XXX cpc serialization, probably per-cpu IRQ disabled
2224 WARN_ON_ONCE(event->ctx != ctx);
2225 lockdep_assert_held(&ctx->lock);
2227 if (event->state != PERF_EVENT_STATE_ACTIVE)
2231 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2232 * we can schedule events _OUT_ individually through things like
2233 * __perf_remove_from_context().
2235 list_del_init(&event->active_list);
2237 perf_pmu_disable(event->pmu);
2239 event->pmu->del(event, 0);
2242 if (event->pending_disable) {
2243 event->pending_disable = 0;
2244 perf_cgroup_event_disable(event, ctx);
2245 state = PERF_EVENT_STATE_OFF;
2248 if (event->pending_sigtrap) {
2251 event->pending_sigtrap = 0;
2252 if (state != PERF_EVENT_STATE_OFF &&
2253 !event->pending_work) {
2254 event->pending_work = 1;
2256 WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount));
2257 task_work_add(current, &event->pending_task, TWA_RESUME);
2260 local_dec(&event->ctx->nr_pending);
2263 perf_event_set_state(event, state);
2265 if (!is_software_event(event))
2266 cpc->active_oncpu--;
2267 if (event->attr.freq && event->attr.sample_freq)
2269 if (event->attr.exclusive || !cpc->active_oncpu)
2272 perf_pmu_enable(event->pmu);
2276 group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx)
2278 struct perf_event *event;
2280 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2283 perf_assert_pmu_disabled(group_event->pmu_ctx->pmu);
2285 event_sched_out(group_event, ctx);
2288 * Schedule out siblings (if any):
2290 for_each_sibling_event(event, group_event)
2291 event_sched_out(event, ctx);
2294 #define DETACH_GROUP 0x01UL
2295 #define DETACH_CHILD 0x02UL
2296 #define DETACH_DEAD 0x04UL
2299 * Cross CPU call to remove a performance event
2301 * We disable the event on the hardware level first. After that we
2302 * remove it from the context list.
2305 __perf_remove_from_context(struct perf_event *event,
2306 struct perf_cpu_context *cpuctx,
2307 struct perf_event_context *ctx,
2310 struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
2311 unsigned long flags = (unsigned long)info;
2313 if (ctx->is_active & EVENT_TIME) {
2314 update_context_time(ctx);
2315 update_cgrp_time_from_cpuctx(cpuctx, false);
2319 * Ensure event_sched_out() switches to OFF, at the very least
2320 * this avoids raising perf_pending_task() at this time.
2322 if (flags & DETACH_DEAD)
2323 event->pending_disable = 1;
2324 event_sched_out(event, ctx);
2325 if (flags & DETACH_GROUP)
2326 perf_group_detach(event);
2327 if (flags & DETACH_CHILD)
2328 perf_child_detach(event);
2329 list_del_event(event, ctx);
2330 if (flags & DETACH_DEAD)
2331 event->state = PERF_EVENT_STATE_DEAD;
2333 if (!pmu_ctx->nr_events) {
2334 pmu_ctx->rotate_necessary = 0;
2336 if (ctx->task && ctx->is_active) {
2337 struct perf_cpu_pmu_context *cpc;
2339 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
2340 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
2341 cpc->task_epc = NULL;
2345 if (!ctx->nr_events && ctx->is_active) {
2346 if (ctx == &cpuctx->ctx)
2347 update_cgrp_time_from_cpuctx(cpuctx, true);
2351 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2352 cpuctx->task_ctx = NULL;
2358 * Remove the event from a task's (or a CPU's) list of events.
2360 * If event->ctx is a cloned context, callers must make sure that
2361 * every task struct that event->ctx->task could possibly point to
2362 * remains valid. This is OK when called from perf_release since
2363 * that only calls us on the top-level context, which can't be a clone.
2364 * When called from perf_event_exit_task, it's OK because the
2365 * context has been detached from its task.
2367 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2369 struct perf_event_context *ctx = event->ctx;
2371 lockdep_assert_held(&ctx->mutex);
2374 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2375 * to work in the face of TASK_TOMBSTONE, unlike every other
2376 * event_function_call() user.
2378 raw_spin_lock_irq(&ctx->lock);
2379 if (!ctx->is_active) {
2380 __perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context),
2381 ctx, (void *)flags);
2382 raw_spin_unlock_irq(&ctx->lock);
2385 raw_spin_unlock_irq(&ctx->lock);
2387 event_function_call(event, __perf_remove_from_context, (void *)flags);
2391 * Cross CPU call to disable a performance event
2393 static void __perf_event_disable(struct perf_event *event,
2394 struct perf_cpu_context *cpuctx,
2395 struct perf_event_context *ctx,
2398 if (event->state < PERF_EVENT_STATE_INACTIVE)
2401 if (ctx->is_active & EVENT_TIME) {
2402 update_context_time(ctx);
2403 update_cgrp_time_from_event(event);
2406 perf_pmu_disable(event->pmu_ctx->pmu);
2408 if (event == event->group_leader)
2409 group_sched_out(event, ctx);
2411 event_sched_out(event, ctx);
2413 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2414 perf_cgroup_event_disable(event, ctx);
2416 perf_pmu_enable(event->pmu_ctx->pmu);
2422 * If event->ctx is a cloned context, callers must make sure that
2423 * every task struct that event->ctx->task could possibly point to
2424 * remains valid. This condition is satisfied when called through
2425 * perf_event_for_each_child or perf_event_for_each because they
2426 * hold the top-level event's child_mutex, so any descendant that
2427 * goes to exit will block in perf_event_exit_event().
2429 * When called from perf_pending_irq it's OK because event->ctx
2430 * is the current context on this CPU and preemption is disabled,
2431 * hence we can't get into perf_event_task_sched_out for this context.
2433 static void _perf_event_disable(struct perf_event *event)
2435 struct perf_event_context *ctx = event->ctx;
2437 raw_spin_lock_irq(&ctx->lock);
2438 if (event->state <= PERF_EVENT_STATE_OFF) {
2439 raw_spin_unlock_irq(&ctx->lock);
2442 raw_spin_unlock_irq(&ctx->lock);
2444 event_function_call(event, __perf_event_disable, NULL);
2447 void perf_event_disable_local(struct perf_event *event)
2449 event_function_local(event, __perf_event_disable, NULL);
2453 * Strictly speaking kernel users cannot create groups and therefore this
2454 * interface does not need the perf_event_ctx_lock() magic.
2456 void perf_event_disable(struct perf_event *event)
2458 struct perf_event_context *ctx;
2460 ctx = perf_event_ctx_lock(event);
2461 _perf_event_disable(event);
2462 perf_event_ctx_unlock(event, ctx);
2464 EXPORT_SYMBOL_GPL(perf_event_disable);
2466 void perf_event_disable_inatomic(struct perf_event *event)
2468 event->pending_disable = 1;
2469 irq_work_queue(&event->pending_irq);
2472 #define MAX_INTERRUPTS (~0ULL)
2474 static void perf_log_throttle(struct perf_event *event, int enable);
2475 static void perf_log_itrace_start(struct perf_event *event);
2478 event_sched_in(struct perf_event *event, struct perf_event_context *ctx)
2480 struct perf_event_pmu_context *epc = event->pmu_ctx;
2481 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2484 WARN_ON_ONCE(event->ctx != ctx);
2486 lockdep_assert_held(&ctx->lock);
2488 if (event->state <= PERF_EVENT_STATE_OFF)
2491 WRITE_ONCE(event->oncpu, smp_processor_id());
2493 * Order event::oncpu write to happen before the ACTIVE state is
2494 * visible. This allows perf_event_{stop,read}() to observe the correct
2495 * ->oncpu if it sees ACTIVE.
2498 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2501 * Unthrottle events, since we scheduled we might have missed several
2502 * ticks already, also for a heavily scheduling task there is little
2503 * guarantee it'll get a tick in a timely manner.
2505 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2506 perf_log_throttle(event, 1);
2507 event->hw.interrupts = 0;
2510 perf_pmu_disable(event->pmu);
2512 perf_log_itrace_start(event);
2514 if (event->pmu->add(event, PERF_EF_START)) {
2515 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2521 if (!is_software_event(event))
2522 cpc->active_oncpu++;
2523 if (event->attr.freq && event->attr.sample_freq)
2526 if (event->attr.exclusive)
2530 perf_pmu_enable(event->pmu);
2536 group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx)
2538 struct perf_event *event, *partial_group = NULL;
2539 struct pmu *pmu = group_event->pmu_ctx->pmu;
2541 if (group_event->state == PERF_EVENT_STATE_OFF)
2544 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2546 if (event_sched_in(group_event, ctx))
2550 * Schedule in siblings as one group (if any):
2552 for_each_sibling_event(event, group_event) {
2553 if (event_sched_in(event, ctx)) {
2554 partial_group = event;
2559 if (!pmu->commit_txn(pmu))
2564 * Groups can be scheduled in as one unit only, so undo any
2565 * partial group before returning:
2566 * The events up to the failed event are scheduled out normally.
2568 for_each_sibling_event(event, group_event) {
2569 if (event == partial_group)
2572 event_sched_out(event, ctx);
2574 event_sched_out(group_event, ctx);
2577 pmu->cancel_txn(pmu);
2582 * Work out whether we can put this event group on the CPU now.
2584 static int group_can_go_on(struct perf_event *event, int can_add_hw)
2586 struct perf_event_pmu_context *epc = event->pmu_ctx;
2587 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2590 * Groups consisting entirely of software events can always go on.
2592 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2595 * If an exclusive group is already on, no other hardware
2601 * If this group is exclusive and there are already
2602 * events on the CPU, it can't go on.
2604 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2607 * Otherwise, try to add it if all previous groups were able
2613 static void add_event_to_ctx(struct perf_event *event,
2614 struct perf_event_context *ctx)
2616 list_add_event(event, ctx);
2617 perf_group_attach(event);
2620 static void task_ctx_sched_out(struct perf_event_context *ctx,
2621 enum event_type_t event_type)
2623 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2625 if (!cpuctx->task_ctx)
2628 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2631 ctx_sched_out(ctx, event_type);
2634 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2635 struct perf_event_context *ctx)
2637 ctx_sched_in(&cpuctx->ctx, EVENT_PINNED);
2639 ctx_sched_in(ctx, EVENT_PINNED);
2640 ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE);
2642 ctx_sched_in(ctx, EVENT_FLEXIBLE);
2646 * We want to maintain the following priority of scheduling:
2647 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2648 * - task pinned (EVENT_PINNED)
2649 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2650 * - task flexible (EVENT_FLEXIBLE).
2652 * In order to avoid unscheduling and scheduling back in everything every
2653 * time an event is added, only do it for the groups of equal priority and
2656 * This can be called after a batch operation on task events, in which case
2657 * event_type is a bit mask of the types of events involved. For CPU events,
2658 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2661 * XXX: ctx_resched() reschedule entire perf_event_context while adding new
2662 * event to the context or enabling existing event in the context. We can
2663 * probably optimize it by rescheduling only affected pmu_ctx.
2665 static void ctx_resched(struct perf_cpu_context *cpuctx,
2666 struct perf_event_context *task_ctx,
2667 enum event_type_t event_type)
2669 bool cpu_event = !!(event_type & EVENT_CPU);
2672 * If pinned groups are involved, flexible groups also need to be
2675 if (event_type & EVENT_PINNED)
2676 event_type |= EVENT_FLEXIBLE;
2678 event_type &= EVENT_ALL;
2680 perf_ctx_disable(&cpuctx->ctx);
2682 perf_ctx_disable(task_ctx);
2683 task_ctx_sched_out(task_ctx, event_type);
2687 * Decide which cpu ctx groups to schedule out based on the types
2688 * of events that caused rescheduling:
2689 * - EVENT_CPU: schedule out corresponding groups;
2690 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2691 * - otherwise, do nothing more.
2694 ctx_sched_out(&cpuctx->ctx, event_type);
2695 else if (event_type & EVENT_PINNED)
2696 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
2698 perf_event_sched_in(cpuctx, task_ctx);
2700 perf_ctx_enable(&cpuctx->ctx);
2702 perf_ctx_enable(task_ctx);
2705 void perf_pmu_resched(struct pmu *pmu)
2707 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2708 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2710 perf_ctx_lock(cpuctx, task_ctx);
2711 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2712 perf_ctx_unlock(cpuctx, task_ctx);
2716 * Cross CPU call to install and enable a performance event
2718 * Very similar to remote_function() + event_function() but cannot assume that
2719 * things like ctx->is_active and cpuctx->task_ctx are set.
2721 static int __perf_install_in_context(void *info)
2723 struct perf_event *event = info;
2724 struct perf_event_context *ctx = event->ctx;
2725 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2726 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2727 bool reprogram = true;
2730 raw_spin_lock(&cpuctx->ctx.lock);
2732 raw_spin_lock(&ctx->lock);
2735 reprogram = (ctx->task == current);
2738 * If the task is running, it must be running on this CPU,
2739 * otherwise we cannot reprogram things.
2741 * If its not running, we don't care, ctx->lock will
2742 * serialize against it becoming runnable.
2744 if (task_curr(ctx->task) && !reprogram) {
2749 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2750 } else if (task_ctx) {
2751 raw_spin_lock(&task_ctx->lock);
2754 #ifdef CONFIG_CGROUP_PERF
2755 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2757 * If the current cgroup doesn't match the event's
2758 * cgroup, we should not try to schedule it.
2760 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2761 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2762 event->cgrp->css.cgroup);
2767 ctx_sched_out(ctx, EVENT_TIME);
2768 add_event_to_ctx(event, ctx);
2769 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2771 add_event_to_ctx(event, ctx);
2775 perf_ctx_unlock(cpuctx, task_ctx);
2780 static bool exclusive_event_installable(struct perf_event *event,
2781 struct perf_event_context *ctx);
2784 * Attach a performance event to a context.
2786 * Very similar to event_function_call, see comment there.
2789 perf_install_in_context(struct perf_event_context *ctx,
2790 struct perf_event *event,
2793 struct task_struct *task = READ_ONCE(ctx->task);
2795 lockdep_assert_held(&ctx->mutex);
2797 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2799 if (event->cpu != -1)
2800 WARN_ON_ONCE(event->cpu != cpu);
2803 * Ensures that if we can observe event->ctx, both the event and ctx
2804 * will be 'complete'. See perf_iterate_sb_cpu().
2806 smp_store_release(&event->ctx, ctx);
2809 * perf_event_attr::disabled events will not run and can be initialized
2810 * without IPI. Except when this is the first event for the context, in
2811 * that case we need the magic of the IPI to set ctx->is_active.
2813 * The IOC_ENABLE that is sure to follow the creation of a disabled
2814 * event will issue the IPI and reprogram the hardware.
2816 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2817 ctx->nr_events && !is_cgroup_event(event)) {
2818 raw_spin_lock_irq(&ctx->lock);
2819 if (ctx->task == TASK_TOMBSTONE) {
2820 raw_spin_unlock_irq(&ctx->lock);
2823 add_event_to_ctx(event, ctx);
2824 raw_spin_unlock_irq(&ctx->lock);
2829 cpu_function_call(cpu, __perf_install_in_context, event);
2834 * Should not happen, we validate the ctx is still alive before calling.
2836 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2840 * Installing events is tricky because we cannot rely on ctx->is_active
2841 * to be set in case this is the nr_events 0 -> 1 transition.
2843 * Instead we use task_curr(), which tells us if the task is running.
2844 * However, since we use task_curr() outside of rq::lock, we can race
2845 * against the actual state. This means the result can be wrong.
2847 * If we get a false positive, we retry, this is harmless.
2849 * If we get a false negative, things are complicated. If we are after
2850 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2851 * value must be correct. If we're before, it doesn't matter since
2852 * perf_event_context_sched_in() will program the counter.
2854 * However, this hinges on the remote context switch having observed
2855 * our task->perf_event_ctxp[] store, such that it will in fact take
2856 * ctx::lock in perf_event_context_sched_in().
2858 * We do this by task_function_call(), if the IPI fails to hit the task
2859 * we know any future context switch of task must see the
2860 * perf_event_ctpx[] store.
2864 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2865 * task_cpu() load, such that if the IPI then does not find the task
2866 * running, a future context switch of that task must observe the
2871 if (!task_function_call(task, __perf_install_in_context, event))
2874 raw_spin_lock_irq(&ctx->lock);
2876 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2878 * Cannot happen because we already checked above (which also
2879 * cannot happen), and we hold ctx->mutex, which serializes us
2880 * against perf_event_exit_task_context().
2882 raw_spin_unlock_irq(&ctx->lock);
2886 * If the task is not running, ctx->lock will avoid it becoming so,
2887 * thus we can safely install the event.
2889 if (task_curr(task)) {
2890 raw_spin_unlock_irq(&ctx->lock);
2893 add_event_to_ctx(event, ctx);
2894 raw_spin_unlock_irq(&ctx->lock);
2898 * Cross CPU call to enable a performance event
2900 static void __perf_event_enable(struct perf_event *event,
2901 struct perf_cpu_context *cpuctx,
2902 struct perf_event_context *ctx,
2905 struct perf_event *leader = event->group_leader;
2906 struct perf_event_context *task_ctx;
2908 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2909 event->state <= PERF_EVENT_STATE_ERROR)
2913 ctx_sched_out(ctx, EVENT_TIME);
2915 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2916 perf_cgroup_event_enable(event, ctx);
2918 if (!ctx->is_active)
2921 if (!event_filter_match(event)) {
2922 ctx_sched_in(ctx, EVENT_TIME);
2927 * If the event is in a group and isn't the group leader,
2928 * then don't put it on unless the group is on.
2930 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2931 ctx_sched_in(ctx, EVENT_TIME);
2935 task_ctx = cpuctx->task_ctx;
2937 WARN_ON_ONCE(task_ctx != ctx);
2939 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2945 * If event->ctx is a cloned context, callers must make sure that
2946 * every task struct that event->ctx->task could possibly point to
2947 * remains valid. This condition is satisfied when called through
2948 * perf_event_for_each_child or perf_event_for_each as described
2949 * for perf_event_disable.
2951 static void _perf_event_enable(struct perf_event *event)
2953 struct perf_event_context *ctx = event->ctx;
2955 raw_spin_lock_irq(&ctx->lock);
2956 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2957 event->state < PERF_EVENT_STATE_ERROR) {
2959 raw_spin_unlock_irq(&ctx->lock);
2964 * If the event is in error state, clear that first.
2966 * That way, if we see the event in error state below, we know that it
2967 * has gone back into error state, as distinct from the task having
2968 * been scheduled away before the cross-call arrived.
2970 if (event->state == PERF_EVENT_STATE_ERROR) {
2972 * Detached SIBLING events cannot leave ERROR state.
2974 if (event->event_caps & PERF_EV_CAP_SIBLING &&
2975 event->group_leader == event)
2978 event->state = PERF_EVENT_STATE_OFF;
2980 raw_spin_unlock_irq(&ctx->lock);
2982 event_function_call(event, __perf_event_enable, NULL);
2986 * See perf_event_disable();
2988 void perf_event_enable(struct perf_event *event)
2990 struct perf_event_context *ctx;
2992 ctx = perf_event_ctx_lock(event);
2993 _perf_event_enable(event);
2994 perf_event_ctx_unlock(event, ctx);
2996 EXPORT_SYMBOL_GPL(perf_event_enable);
2998 struct stop_event_data {
2999 struct perf_event *event;
3000 unsigned int restart;
3003 static int __perf_event_stop(void *info)
3005 struct stop_event_data *sd = info;
3006 struct perf_event *event = sd->event;
3008 /* if it's already INACTIVE, do nothing */
3009 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3012 /* matches smp_wmb() in event_sched_in() */
3016 * There is a window with interrupts enabled before we get here,
3017 * so we need to check again lest we try to stop another CPU's event.
3019 if (READ_ONCE(event->oncpu) != smp_processor_id())
3022 event->pmu->stop(event, PERF_EF_UPDATE);
3025 * May race with the actual stop (through perf_pmu_output_stop()),
3026 * but it is only used for events with AUX ring buffer, and such
3027 * events will refuse to restart because of rb::aux_mmap_count==0,
3028 * see comments in perf_aux_output_begin().
3030 * Since this is happening on an event-local CPU, no trace is lost
3034 event->pmu->start(event, 0);
3039 static int perf_event_stop(struct perf_event *event, int restart)
3041 struct stop_event_data sd = {
3048 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3051 /* matches smp_wmb() in event_sched_in() */
3055 * We only want to restart ACTIVE events, so if the event goes
3056 * inactive here (event->oncpu==-1), there's nothing more to do;
3057 * fall through with ret==-ENXIO.
3059 ret = cpu_function_call(READ_ONCE(event->oncpu),
3060 __perf_event_stop, &sd);
3061 } while (ret == -EAGAIN);
3067 * In order to contain the amount of racy and tricky in the address filter
3068 * configuration management, it is a two part process:
3070 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3071 * we update the addresses of corresponding vmas in
3072 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3073 * (p2) when an event is scheduled in (pmu::add), it calls
3074 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3075 * if the generation has changed since the previous call.
3077 * If (p1) happens while the event is active, we restart it to force (p2).
3079 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3080 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3082 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3083 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3085 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3088 void perf_event_addr_filters_sync(struct perf_event *event)
3090 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3092 if (!has_addr_filter(event))
3095 raw_spin_lock(&ifh->lock);
3096 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3097 event->pmu->addr_filters_sync(event);
3098 event->hw.addr_filters_gen = event->addr_filters_gen;
3100 raw_spin_unlock(&ifh->lock);
3102 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3104 static int _perf_event_refresh(struct perf_event *event, int refresh)
3107 * not supported on inherited events
3109 if (event->attr.inherit || !is_sampling_event(event))
3112 atomic_add(refresh, &event->event_limit);
3113 _perf_event_enable(event);
3119 * See perf_event_disable()
3121 int perf_event_refresh(struct perf_event *event, int refresh)
3123 struct perf_event_context *ctx;
3126 ctx = perf_event_ctx_lock(event);
3127 ret = _perf_event_refresh(event, refresh);
3128 perf_event_ctx_unlock(event, ctx);
3132 EXPORT_SYMBOL_GPL(perf_event_refresh);
3134 static int perf_event_modify_breakpoint(struct perf_event *bp,
3135 struct perf_event_attr *attr)
3139 _perf_event_disable(bp);
3141 err = modify_user_hw_breakpoint_check(bp, attr, true);
3143 if (!bp->attr.disabled)
3144 _perf_event_enable(bp);
3150 * Copy event-type-independent attributes that may be modified.
3152 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3153 const struct perf_event_attr *from)
3155 to->sig_data = from->sig_data;
3158 static int perf_event_modify_attr(struct perf_event *event,
3159 struct perf_event_attr *attr)
3161 int (*func)(struct perf_event *, struct perf_event_attr *);
3162 struct perf_event *child;
3165 if (event->attr.type != attr->type)
3168 switch (event->attr.type) {
3169 case PERF_TYPE_BREAKPOINT:
3170 func = perf_event_modify_breakpoint;
3173 /* Place holder for future additions. */
3177 WARN_ON_ONCE(event->ctx->parent_ctx);
3179 mutex_lock(&event->child_mutex);
3181 * Event-type-independent attributes must be copied before event-type
3182 * modification, which will validate that final attributes match the
3183 * source attributes after all relevant attributes have been copied.
3185 perf_event_modify_copy_attr(&event->attr, attr);
3186 err = func(event, attr);
3189 list_for_each_entry(child, &event->child_list, child_list) {
3190 perf_event_modify_copy_attr(&child->attr, attr);
3191 err = func(child, attr);
3196 mutex_unlock(&event->child_mutex);
3200 static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx,
3201 enum event_type_t event_type)
3203 struct perf_event_context *ctx = pmu_ctx->ctx;
3204 struct perf_event *event, *tmp;
3205 struct pmu *pmu = pmu_ctx->pmu;
3207 if (ctx->task && !ctx->is_active) {
3208 struct perf_cpu_pmu_context *cpc;
3210 cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3211 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3212 cpc->task_epc = NULL;
3218 perf_pmu_disable(pmu);
3219 if (event_type & EVENT_PINNED) {
3220 list_for_each_entry_safe(event, tmp,
3221 &pmu_ctx->pinned_active,
3223 group_sched_out(event, ctx);
3226 if (event_type & EVENT_FLEXIBLE) {
3227 list_for_each_entry_safe(event, tmp,
3228 &pmu_ctx->flexible_active,
3230 group_sched_out(event, ctx);
3232 * Since we cleared EVENT_FLEXIBLE, also clear
3233 * rotate_necessary, is will be reset by
3234 * ctx_flexible_sched_in() when needed.
3236 pmu_ctx->rotate_necessary = 0;
3238 perf_pmu_enable(pmu);
3242 ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type)
3244 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3245 struct perf_event_pmu_context *pmu_ctx;
3246 int is_active = ctx->is_active;
3248 lockdep_assert_held(&ctx->lock);
3250 if (likely(!ctx->nr_events)) {
3252 * See __perf_remove_from_context().
3254 WARN_ON_ONCE(ctx->is_active);
3256 WARN_ON_ONCE(cpuctx->task_ctx);
3261 * Always update time if it was set; not only when it changes.
3262 * Otherwise we can 'forget' to update time for any but the last
3263 * context we sched out. For example:
3265 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3266 * ctx_sched_out(.event_type = EVENT_PINNED)
3268 * would only update time for the pinned events.
3270 if (is_active & EVENT_TIME) {
3271 /* update (and stop) ctx time */
3272 update_context_time(ctx);
3273 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3275 * CPU-release for the below ->is_active store,
3276 * see __load_acquire() in perf_event_time_now()
3281 ctx->is_active &= ~event_type;
3282 if (!(ctx->is_active & EVENT_ALL))
3286 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3287 if (!ctx->is_active)
3288 cpuctx->task_ctx = NULL;
3291 is_active ^= ctx->is_active; /* changed bits */
3293 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
3294 __pmu_ctx_sched_out(pmu_ctx, is_active);
3298 * Test whether two contexts are equivalent, i.e. whether they have both been
3299 * cloned from the same version of the same context.
3301 * Equivalence is measured using a generation number in the context that is
3302 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3303 * and list_del_event().
3305 static int context_equiv(struct perf_event_context *ctx1,
3306 struct perf_event_context *ctx2)
3308 lockdep_assert_held(&ctx1->lock);
3309 lockdep_assert_held(&ctx2->lock);
3311 /* Pinning disables the swap optimization */
3312 if (ctx1->pin_count || ctx2->pin_count)
3315 /* If ctx1 is the parent of ctx2 */
3316 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3319 /* If ctx2 is the parent of ctx1 */
3320 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3324 * If ctx1 and ctx2 have the same parent; we flatten the parent
3325 * hierarchy, see perf_event_init_context().
3327 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3328 ctx1->parent_gen == ctx2->parent_gen)
3335 static void __perf_event_sync_stat(struct perf_event *event,
3336 struct perf_event *next_event)
3340 if (!event->attr.inherit_stat)
3344 * Update the event value, we cannot use perf_event_read()
3345 * because we're in the middle of a context switch and have IRQs
3346 * disabled, which upsets smp_call_function_single(), however
3347 * we know the event must be on the current CPU, therefore we
3348 * don't need to use it.
3350 if (event->state == PERF_EVENT_STATE_ACTIVE)
3351 event->pmu->read(event);
3353 perf_event_update_time(event);
3356 * In order to keep per-task stats reliable we need to flip the event
3357 * values when we flip the contexts.
3359 value = local64_read(&next_event->count);
3360 value = local64_xchg(&event->count, value);
3361 local64_set(&next_event->count, value);
3363 swap(event->total_time_enabled, next_event->total_time_enabled);
3364 swap(event->total_time_running, next_event->total_time_running);
3367 * Since we swizzled the values, update the user visible data too.
3369 perf_event_update_userpage(event);
3370 perf_event_update_userpage(next_event);
3373 static void perf_event_sync_stat(struct perf_event_context *ctx,
3374 struct perf_event_context *next_ctx)
3376 struct perf_event *event, *next_event;
3381 update_context_time(ctx);
3383 event = list_first_entry(&ctx->event_list,
3384 struct perf_event, event_entry);
3386 next_event = list_first_entry(&next_ctx->event_list,
3387 struct perf_event, event_entry);
3389 while (&event->event_entry != &ctx->event_list &&
3390 &next_event->event_entry != &next_ctx->event_list) {
3392 __perf_event_sync_stat(event, next_event);
3394 event = list_next_entry(event, event_entry);
3395 next_event = list_next_entry(next_event, event_entry);
3399 #define double_list_for_each_entry(pos1, pos2, head1, head2, member) \
3400 for (pos1 = list_first_entry(head1, typeof(*pos1), member), \
3401 pos2 = list_first_entry(head2, typeof(*pos2), member); \
3402 !list_entry_is_head(pos1, head1, member) && \
3403 !list_entry_is_head(pos2, head2, member); \
3404 pos1 = list_next_entry(pos1, member), \
3405 pos2 = list_next_entry(pos2, member))
3407 static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx,
3408 struct perf_event_context *next_ctx)
3410 struct perf_event_pmu_context *prev_epc, *next_epc;
3412 if (!prev_ctx->nr_task_data)
3415 double_list_for_each_entry(prev_epc, next_epc,
3416 &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list,
3419 if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu))
3423 * PMU specific parts of task perf context can require
3424 * additional synchronization. As an example of such
3425 * synchronization see implementation details of Intel
3426 * LBR call stack data profiling;
3428 if (prev_epc->pmu->swap_task_ctx)
3429 prev_epc->pmu->swap_task_ctx(prev_epc, next_epc);
3431 swap(prev_epc->task_ctx_data, next_epc->task_ctx_data);
3435 static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in)
3437 struct perf_event_pmu_context *pmu_ctx;
3438 struct perf_cpu_pmu_context *cpc;
3440 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3441 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3443 if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task)
3444 pmu_ctx->pmu->sched_task(pmu_ctx, sched_in);
3449 perf_event_context_sched_out(struct task_struct *task, struct task_struct *next)
3451 struct perf_event_context *ctx = task->perf_event_ctxp;
3452 struct perf_event_context *next_ctx;
3453 struct perf_event_context *parent, *next_parent;
3460 next_ctx = rcu_dereference(next->perf_event_ctxp);
3464 parent = rcu_dereference(ctx->parent_ctx);
3465 next_parent = rcu_dereference(next_ctx->parent_ctx);
3467 /* If neither context have a parent context; they cannot be clones. */
3468 if (!parent && !next_parent)
3471 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3473 * Looks like the two contexts are clones, so we might be
3474 * able to optimize the context switch. We lock both
3475 * contexts and check that they are clones under the
3476 * lock (including re-checking that neither has been
3477 * uncloned in the meantime). It doesn't matter which
3478 * order we take the locks because no other cpu could
3479 * be trying to lock both of these tasks.
3481 raw_spin_lock(&ctx->lock);
3482 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3483 if (context_equiv(ctx, next_ctx)) {
3485 perf_ctx_disable(ctx);
3487 /* PMIs are disabled; ctx->nr_pending is stable. */
3488 if (local_read(&ctx->nr_pending) ||
3489 local_read(&next_ctx->nr_pending)) {
3491 * Must not swap out ctx when there's pending
3492 * events that rely on the ctx->task relation.
3494 raw_spin_unlock(&next_ctx->lock);
3499 WRITE_ONCE(ctx->task, next);
3500 WRITE_ONCE(next_ctx->task, task);
3502 perf_ctx_sched_task_cb(ctx, false);
3503 perf_event_swap_task_ctx_data(ctx, next_ctx);
3505 perf_ctx_enable(ctx);
3508 * RCU_INIT_POINTER here is safe because we've not
3509 * modified the ctx and the above modification of
3510 * ctx->task and ctx->task_ctx_data are immaterial
3511 * since those values are always verified under
3512 * ctx->lock which we're now holding.
3514 RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx);
3515 RCU_INIT_POINTER(next->perf_event_ctxp, ctx);
3519 perf_event_sync_stat(ctx, next_ctx);
3521 raw_spin_unlock(&next_ctx->lock);
3522 raw_spin_unlock(&ctx->lock);
3528 raw_spin_lock(&ctx->lock);
3529 perf_ctx_disable(ctx);
3532 perf_ctx_sched_task_cb(ctx, false);
3533 task_ctx_sched_out(ctx, EVENT_ALL);
3535 perf_ctx_enable(ctx);
3536 raw_spin_unlock(&ctx->lock);
3540 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3541 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
3543 void perf_sched_cb_dec(struct pmu *pmu)
3545 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3547 this_cpu_dec(perf_sched_cb_usages);
3550 if (!--cpc->sched_cb_usage)
3551 list_del(&cpc->sched_cb_entry);
3555 void perf_sched_cb_inc(struct pmu *pmu)
3557 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3559 if (!cpc->sched_cb_usage++)
3560 list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3563 this_cpu_inc(perf_sched_cb_usages);
3567 * This function provides the context switch callback to the lower code
3568 * layer. It is invoked ONLY when the context switch callback is enabled.
3570 * This callback is relevant even to per-cpu events; for example multi event
3571 * PEBS requires this to provide PID/TID information. This requires we flush
3572 * all queued PEBS records before we context switch to a new task.
3574 static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in)
3576 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3581 /* software PMUs will not have sched_task */
3582 if (WARN_ON_ONCE(!pmu->sched_task))
3585 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3586 perf_pmu_disable(pmu);
3588 pmu->sched_task(cpc->task_epc, sched_in);
3590 perf_pmu_enable(pmu);
3591 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3594 static void perf_pmu_sched_task(struct task_struct *prev,
3595 struct task_struct *next,
3598 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3599 struct perf_cpu_pmu_context *cpc;
3601 /* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */
3602 if (prev == next || cpuctx->task_ctx)
3605 list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry)
3606 __perf_pmu_sched_task(cpc, sched_in);
3609 static void perf_event_switch(struct task_struct *task,
3610 struct task_struct *next_prev, bool sched_in);
3613 * Called from scheduler to remove the events of the current task,
3614 * with interrupts disabled.
3616 * We stop each event and update the event value in event->count.
3618 * This does not protect us against NMI, but disable()
3619 * sets the disabled bit in the control field of event _before_
3620 * accessing the event control register. If a NMI hits, then it will
3621 * not restart the event.
3623 void __perf_event_task_sched_out(struct task_struct *task,
3624 struct task_struct *next)
3626 if (__this_cpu_read(perf_sched_cb_usages))
3627 perf_pmu_sched_task(task, next, false);
3629 if (atomic_read(&nr_switch_events))
3630 perf_event_switch(task, next, false);
3632 perf_event_context_sched_out(task, next);
3635 * if cgroup events exist on this CPU, then we need
3636 * to check if we have to switch out PMU state.
3637 * cgroup event are system-wide mode only
3639 perf_cgroup_switch(next);
3642 static bool perf_less_group_idx(const void *l, const void *r)
3644 const struct perf_event *le = *(const struct perf_event **)l;
3645 const struct perf_event *re = *(const struct perf_event **)r;
3647 return le->group_index < re->group_index;
3650 static void swap_ptr(void *l, void *r)
3652 void **lp = l, **rp = r;
3657 static const struct min_heap_callbacks perf_min_heap = {
3658 .elem_size = sizeof(struct perf_event *),
3659 .less = perf_less_group_idx,
3663 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3665 struct perf_event **itrs = heap->data;
3668 itrs[heap->nr] = event;
3673 static void __link_epc(struct perf_event_pmu_context *pmu_ctx)
3675 struct perf_cpu_pmu_context *cpc;
3677 if (!pmu_ctx->ctx->task)
3680 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3681 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3682 cpc->task_epc = pmu_ctx;
3685 static noinline int visit_groups_merge(struct perf_event_context *ctx,
3686 struct perf_event_groups *groups, int cpu,
3688 int (*func)(struct perf_event *, void *),
3691 #ifdef CONFIG_CGROUP_PERF
3692 struct cgroup_subsys_state *css = NULL;
3694 struct perf_cpu_context *cpuctx = NULL;
3695 /* Space for per CPU and/or any CPU event iterators. */
3696 struct perf_event *itrs[2];
3697 struct min_heap event_heap;
3698 struct perf_event **evt;
3701 if (pmu->filter && pmu->filter(pmu, cpu))
3705 cpuctx = this_cpu_ptr(&perf_cpu_context);
3706 event_heap = (struct min_heap){
3707 .data = cpuctx->heap,
3709 .size = cpuctx->heap_size,
3712 lockdep_assert_held(&cpuctx->ctx.lock);
3714 #ifdef CONFIG_CGROUP_PERF
3716 css = &cpuctx->cgrp->css;
3719 event_heap = (struct min_heap){
3722 .size = ARRAY_SIZE(itrs),
3724 /* Events not within a CPU context may be on any CPU. */
3725 __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL));
3727 evt = event_heap.data;
3729 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL));
3731 #ifdef CONFIG_CGROUP_PERF
3732 for (; css; css = css->parent)
3733 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup));
3736 if (event_heap.nr) {
3737 __link_epc((*evt)->pmu_ctx);
3738 perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu);
3741 min_heapify_all(&event_heap, &perf_min_heap);
3743 while (event_heap.nr) {
3744 ret = func(*evt, data);
3748 *evt = perf_event_groups_next(*evt, pmu);
3750 min_heapify(&event_heap, 0, &perf_min_heap);
3752 min_heap_pop(&event_heap, &perf_min_heap);
3759 * Because the userpage is strictly per-event (there is no concept of context,
3760 * so there cannot be a context indirection), every userpage must be updated
3761 * when context time starts :-(
3763 * IOW, we must not miss EVENT_TIME edges.
3765 static inline bool event_update_userpage(struct perf_event *event)
3767 if (likely(!atomic_read(&event->mmap_count)))
3770 perf_event_update_time(event);
3771 perf_event_update_userpage(event);
3776 static inline void group_update_userpage(struct perf_event *group_event)
3778 struct perf_event *event;
3780 if (!event_update_userpage(group_event))
3783 for_each_sibling_event(event, group_event)
3784 event_update_userpage(event);
3787 static int merge_sched_in(struct perf_event *event, void *data)
3789 struct perf_event_context *ctx = event->ctx;
3790 int *can_add_hw = data;
3792 if (event->state <= PERF_EVENT_STATE_OFF)
3795 if (!event_filter_match(event))
3798 if (group_can_go_on(event, *can_add_hw)) {
3799 if (!group_sched_in(event, ctx))
3800 list_add_tail(&event->active_list, get_event_list(event));
3803 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3805 if (event->attr.pinned) {
3806 perf_cgroup_event_disable(event, ctx);
3807 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3809 struct perf_cpu_pmu_context *cpc;
3811 event->pmu_ctx->rotate_necessary = 1;
3812 cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context);
3813 perf_mux_hrtimer_restart(cpc);
3814 group_update_userpage(event);
3821 static void ctx_pinned_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3823 struct perf_event_pmu_context *pmu_ctx;
3827 visit_groups_merge(ctx, &ctx->pinned_groups,
3828 smp_processor_id(), pmu,
3829 merge_sched_in, &can_add_hw);
3831 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3833 visit_groups_merge(ctx, &ctx->pinned_groups,
3834 smp_processor_id(), pmu_ctx->pmu,
3835 merge_sched_in, &can_add_hw);
3840 static void ctx_flexible_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3842 struct perf_event_pmu_context *pmu_ctx;
3846 visit_groups_merge(ctx, &ctx->flexible_groups,
3847 smp_processor_id(), pmu,
3848 merge_sched_in, &can_add_hw);
3850 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3852 visit_groups_merge(ctx, &ctx->flexible_groups,
3853 smp_processor_id(), pmu_ctx->pmu,
3854 merge_sched_in, &can_add_hw);
3859 static void __pmu_ctx_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3861 ctx_flexible_sched_in(ctx, pmu);
3865 ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type)
3867 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3868 int is_active = ctx->is_active;
3870 lockdep_assert_held(&ctx->lock);
3872 if (likely(!ctx->nr_events))
3875 if (!(is_active & EVENT_TIME)) {
3876 /* start ctx time */
3877 __update_context_time(ctx, false);
3878 perf_cgroup_set_timestamp(cpuctx);
3880 * CPU-release for the below ->is_active store,
3881 * see __load_acquire() in perf_event_time_now()
3886 ctx->is_active |= (event_type | EVENT_TIME);
3889 cpuctx->task_ctx = ctx;
3891 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3894 is_active ^= ctx->is_active; /* changed bits */
3897 * First go through the list and put on any pinned groups
3898 * in order to give them the best chance of going on.
3900 if (is_active & EVENT_PINNED)
3901 ctx_pinned_sched_in(ctx, NULL);
3903 /* Then walk through the lower prio flexible groups */
3904 if (is_active & EVENT_FLEXIBLE)
3905 ctx_flexible_sched_in(ctx, NULL);
3908 static void perf_event_context_sched_in(struct task_struct *task)
3910 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3911 struct perf_event_context *ctx;
3914 ctx = rcu_dereference(task->perf_event_ctxp);
3918 if (cpuctx->task_ctx == ctx) {
3919 perf_ctx_lock(cpuctx, ctx);
3920 perf_ctx_disable(ctx);
3922 perf_ctx_sched_task_cb(ctx, true);
3924 perf_ctx_enable(ctx);
3925 perf_ctx_unlock(cpuctx, ctx);
3929 perf_ctx_lock(cpuctx, ctx);
3931 * We must check ctx->nr_events while holding ctx->lock, such
3932 * that we serialize against perf_install_in_context().
3934 if (!ctx->nr_events)
3937 perf_ctx_disable(ctx);
3939 * We want to keep the following priority order:
3940 * cpu pinned (that don't need to move), task pinned,
3941 * cpu flexible, task flexible.
3943 * However, if task's ctx is not carrying any pinned
3944 * events, no need to flip the cpuctx's events around.
3946 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) {
3947 perf_ctx_disable(&cpuctx->ctx);
3948 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
3951 perf_event_sched_in(cpuctx, ctx);
3953 perf_ctx_sched_task_cb(cpuctx->task_ctx, true);
3955 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3956 perf_ctx_enable(&cpuctx->ctx);
3958 perf_ctx_enable(ctx);
3961 perf_ctx_unlock(cpuctx, ctx);
3967 * Called from scheduler to add the events of the current task
3968 * with interrupts disabled.
3970 * We restore the event value and then enable it.
3972 * This does not protect us against NMI, but enable()
3973 * sets the enabled bit in the control field of event _before_
3974 * accessing the event control register. If a NMI hits, then it will
3975 * keep the event running.
3977 void __perf_event_task_sched_in(struct task_struct *prev,
3978 struct task_struct *task)
3980 perf_event_context_sched_in(task);
3982 if (atomic_read(&nr_switch_events))
3983 perf_event_switch(task, prev, true);
3985 if (__this_cpu_read(perf_sched_cb_usages))
3986 perf_pmu_sched_task(prev, task, true);
3989 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3991 u64 frequency = event->attr.sample_freq;
3992 u64 sec = NSEC_PER_SEC;
3993 u64 divisor, dividend;
3995 int count_fls, nsec_fls, frequency_fls, sec_fls;
3997 count_fls = fls64(count);
3998 nsec_fls = fls64(nsec);
3999 frequency_fls = fls64(frequency);
4003 * We got @count in @nsec, with a target of sample_freq HZ
4004 * the target period becomes:
4007 * period = -------------------
4008 * @nsec * sample_freq
4013 * Reduce accuracy by one bit such that @a and @b converge
4014 * to a similar magnitude.
4016 #define REDUCE_FLS(a, b) \
4018 if (a##_fls > b##_fls) { \
4028 * Reduce accuracy until either term fits in a u64, then proceed with
4029 * the other, so that finally we can do a u64/u64 division.
4031 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4032 REDUCE_FLS(nsec, frequency);
4033 REDUCE_FLS(sec, count);
4036 if (count_fls + sec_fls > 64) {
4037 divisor = nsec * frequency;
4039 while (count_fls + sec_fls > 64) {
4040 REDUCE_FLS(count, sec);
4044 dividend = count * sec;
4046 dividend = count * sec;
4048 while (nsec_fls + frequency_fls > 64) {
4049 REDUCE_FLS(nsec, frequency);
4053 divisor = nsec * frequency;
4059 return div64_u64(dividend, divisor);
4062 static DEFINE_PER_CPU(int, perf_throttled_count);
4063 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4065 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4067 struct hw_perf_event *hwc = &event->hw;
4068 s64 period, sample_period;
4071 period = perf_calculate_period(event, nsec, count);
4073 delta = (s64)(period - hwc->sample_period);
4074 delta = (delta + 7) / 8; /* low pass filter */
4076 sample_period = hwc->sample_period + delta;
4081 hwc->sample_period = sample_period;
4083 if (local64_read(&hwc->period_left) > 8*sample_period) {
4085 event->pmu->stop(event, PERF_EF_UPDATE);
4087 local64_set(&hwc->period_left, 0);
4090 event->pmu->start(event, PERF_EF_RELOAD);
4095 * combine freq adjustment with unthrottling to avoid two passes over the
4096 * events. At the same time, make sure, having freq events does not change
4097 * the rate of unthrottling as that would introduce bias.
4100 perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle)
4102 struct perf_event *event;
4103 struct hw_perf_event *hwc;
4104 u64 now, period = TICK_NSEC;
4108 * only need to iterate over all events iff:
4109 * - context have events in frequency mode (needs freq adjust)
4110 * - there are events to unthrottle on this cpu
4112 if (!(ctx->nr_freq || unthrottle))
4115 raw_spin_lock(&ctx->lock);
4117 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4118 if (event->state != PERF_EVENT_STATE_ACTIVE)
4121 // XXX use visit thingy to avoid the -1,cpu match
4122 if (!event_filter_match(event))
4125 perf_pmu_disable(event->pmu);
4129 if (hwc->interrupts == MAX_INTERRUPTS) {
4130 hwc->interrupts = 0;
4131 perf_log_throttle(event, 1);
4132 event->pmu->start(event, 0);
4135 if (!event->attr.freq || !event->attr.sample_freq)
4139 * stop the event and update event->count
4141 event->pmu->stop(event, PERF_EF_UPDATE);
4143 now = local64_read(&event->count);
4144 delta = now - hwc->freq_count_stamp;
4145 hwc->freq_count_stamp = now;
4149 * reload only if value has changed
4150 * we have stopped the event so tell that
4151 * to perf_adjust_period() to avoid stopping it
4155 perf_adjust_period(event, period, delta, false);
4157 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4159 perf_pmu_enable(event->pmu);
4162 raw_spin_unlock(&ctx->lock);
4166 * Move @event to the tail of the @ctx's elegible events.
4168 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4171 * Rotate the first entry last of non-pinned groups. Rotation might be
4172 * disabled by the inheritance code.
4174 if (ctx->rotate_disable)
4177 perf_event_groups_delete(&ctx->flexible_groups, event);
4178 perf_event_groups_insert(&ctx->flexible_groups, event);
4181 /* pick an event from the flexible_groups to rotate */
4182 static inline struct perf_event *
4183 ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx)
4185 struct perf_event *event;
4186 struct rb_node *node;
4187 struct rb_root *tree;
4188 struct __group_key key = {
4189 .pmu = pmu_ctx->pmu,
4192 /* pick the first active flexible event */
4193 event = list_first_entry_or_null(&pmu_ctx->flexible_active,
4194 struct perf_event, active_list);
4198 /* if no active flexible event, pick the first event */
4199 tree = &pmu_ctx->ctx->flexible_groups.tree;
4201 if (!pmu_ctx->ctx->task) {
4202 key.cpu = smp_processor_id();
4204 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4206 event = __node_2_pe(node);
4211 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4213 event = __node_2_pe(node);
4217 key.cpu = smp_processor_id();
4218 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4220 event = __node_2_pe(node);
4224 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4225 * finds there are unschedulable events, it will set it again.
4227 pmu_ctx->rotate_necessary = 0;
4232 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc)
4234 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4235 struct perf_event_pmu_context *cpu_epc, *task_epc = NULL;
4236 struct perf_event *cpu_event = NULL, *task_event = NULL;
4237 int cpu_rotate, task_rotate;
4241 * Since we run this from IRQ context, nobody can install new
4242 * events, thus the event count values are stable.
4245 cpu_epc = &cpc->epc;
4247 task_epc = cpc->task_epc;
4249 cpu_rotate = cpu_epc->rotate_necessary;
4250 task_rotate = task_epc ? task_epc->rotate_necessary : 0;
4252 if (!(cpu_rotate || task_rotate))
4255 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4256 perf_pmu_disable(pmu);
4259 task_event = ctx_event_to_rotate(task_epc);
4261 cpu_event = ctx_event_to_rotate(cpu_epc);
4264 * As per the order given at ctx_resched() first 'pop' task flexible
4265 * and then, if needed CPU flexible.
4267 if (task_event || (task_epc && cpu_event)) {
4268 update_context_time(task_epc->ctx);
4269 __pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE);
4273 update_context_time(&cpuctx->ctx);
4274 __pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE);
4275 rotate_ctx(&cpuctx->ctx, cpu_event);
4276 __pmu_ctx_sched_in(&cpuctx->ctx, pmu);
4280 rotate_ctx(task_epc->ctx, task_event);
4282 if (task_event || (task_epc && cpu_event))
4283 __pmu_ctx_sched_in(task_epc->ctx, pmu);
4285 perf_pmu_enable(pmu);
4286 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4291 void perf_event_task_tick(void)
4293 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4294 struct perf_event_context *ctx;
4297 lockdep_assert_irqs_disabled();
4299 __this_cpu_inc(perf_throttled_seq);
4300 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4301 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4303 perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled);
4306 ctx = rcu_dereference(current->perf_event_ctxp);
4308 perf_adjust_freq_unthr_context(ctx, !!throttled);
4312 static int event_enable_on_exec(struct perf_event *event,
4313 struct perf_event_context *ctx)
4315 if (!event->attr.enable_on_exec)
4318 event->attr.enable_on_exec = 0;
4319 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4322 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4328 * Enable all of a task's events that have been marked enable-on-exec.
4329 * This expects task == current.
4331 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
4333 struct perf_event_context *clone_ctx = NULL;
4334 enum event_type_t event_type = 0;
4335 struct perf_cpu_context *cpuctx;
4336 struct perf_event *event;
4337 unsigned long flags;
4340 local_irq_save(flags);
4341 if (WARN_ON_ONCE(current->perf_event_ctxp != ctx))
4344 if (!ctx->nr_events)
4347 cpuctx = this_cpu_ptr(&perf_cpu_context);
4348 perf_ctx_lock(cpuctx, ctx);
4349 ctx_sched_out(ctx, EVENT_TIME);
4351 list_for_each_entry(event, &ctx->event_list, event_entry) {
4352 enabled |= event_enable_on_exec(event, ctx);
4353 event_type |= get_event_type(event);
4357 * Unclone and reschedule this context if we enabled any event.
4360 clone_ctx = unclone_ctx(ctx);
4361 ctx_resched(cpuctx, ctx, event_type);
4363 ctx_sched_in(ctx, EVENT_TIME);
4365 perf_ctx_unlock(cpuctx, ctx);
4368 local_irq_restore(flags);
4374 static void perf_remove_from_owner(struct perf_event *event);
4375 static void perf_event_exit_event(struct perf_event *event,
4376 struct perf_event_context *ctx);
4379 * Removes all events from the current task that have been marked
4380 * remove-on-exec, and feeds their values back to parent events.
4382 static void perf_event_remove_on_exec(struct perf_event_context *ctx)
4384 struct perf_event_context *clone_ctx = NULL;
4385 struct perf_event *event, *next;
4386 unsigned long flags;
4387 bool modified = false;
4389 mutex_lock(&ctx->mutex);
4391 if (WARN_ON_ONCE(ctx->task != current))
4394 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4395 if (!event->attr.remove_on_exec)
4398 if (!is_kernel_event(event))
4399 perf_remove_from_owner(event);
4403 perf_event_exit_event(event, ctx);
4406 raw_spin_lock_irqsave(&ctx->lock, flags);
4408 clone_ctx = unclone_ctx(ctx);
4409 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4412 mutex_unlock(&ctx->mutex);
4418 struct perf_read_data {
4419 struct perf_event *event;
4424 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4426 u16 local_pkg, event_pkg;
4428 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4429 int local_cpu = smp_processor_id();
4431 event_pkg = topology_physical_package_id(event_cpu);
4432 local_pkg = topology_physical_package_id(local_cpu);
4434 if (event_pkg == local_pkg)
4442 * Cross CPU call to read the hardware event
4444 static void __perf_event_read(void *info)
4446 struct perf_read_data *data = info;
4447 struct perf_event *sub, *event = data->event;
4448 struct perf_event_context *ctx = event->ctx;
4449 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4450 struct pmu *pmu = event->pmu;
4453 * If this is a task context, we need to check whether it is
4454 * the current task context of this cpu. If not it has been
4455 * scheduled out before the smp call arrived. In that case
4456 * event->count would have been updated to a recent sample
4457 * when the event was scheduled out.
4459 if (ctx->task && cpuctx->task_ctx != ctx)
4462 raw_spin_lock(&ctx->lock);
4463 if (ctx->is_active & EVENT_TIME) {
4464 update_context_time(ctx);
4465 update_cgrp_time_from_event(event);
4468 perf_event_update_time(event);
4470 perf_event_update_sibling_time(event);
4472 if (event->state != PERF_EVENT_STATE_ACTIVE)
4481 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4485 for_each_sibling_event(sub, event) {
4486 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4488 * Use sibling's PMU rather than @event's since
4489 * sibling could be on different (eg: software) PMU.
4491 sub->pmu->read(sub);
4495 data->ret = pmu->commit_txn(pmu);
4498 raw_spin_unlock(&ctx->lock);
4501 static inline u64 perf_event_count(struct perf_event *event)
4503 return local64_read(&event->count) + atomic64_read(&event->child_count);
4506 static void calc_timer_values(struct perf_event *event,
4513 *now = perf_clock();
4514 ctx_time = perf_event_time_now(event, *now);
4515 __perf_update_times(event, ctx_time, enabled, running);
4519 * NMI-safe method to read a local event, that is an event that
4521 * - either for the current task, or for this CPU
4522 * - does not have inherit set, for inherited task events
4523 * will not be local and we cannot read them atomically
4524 * - must not have a pmu::count method
4526 int perf_event_read_local(struct perf_event *event, u64 *value,
4527 u64 *enabled, u64 *running)
4529 unsigned long flags;
4533 * Disabling interrupts avoids all counter scheduling (context
4534 * switches, timer based rotation and IPIs).
4536 local_irq_save(flags);
4539 * It must not be an event with inherit set, we cannot read
4540 * all child counters from atomic context.
4542 if (event->attr.inherit) {
4547 /* If this is a per-task event, it must be for current */
4548 if ((event->attach_state & PERF_ATTACH_TASK) &&
4549 event->hw.target != current) {
4554 /* If this is a per-CPU event, it must be for this CPU */
4555 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4556 event->cpu != smp_processor_id()) {
4561 /* If this is a pinned event it must be running on this CPU */
4562 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4568 * If the event is currently on this CPU, its either a per-task event,
4569 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4572 if (event->oncpu == smp_processor_id())
4573 event->pmu->read(event);
4575 *value = local64_read(&event->count);
4576 if (enabled || running) {
4577 u64 __enabled, __running, __now;
4579 calc_timer_values(event, &__now, &__enabled, &__running);
4581 *enabled = __enabled;
4583 *running = __running;
4586 local_irq_restore(flags);
4591 static int perf_event_read(struct perf_event *event, bool group)
4593 enum perf_event_state state = READ_ONCE(event->state);
4594 int event_cpu, ret = 0;
4597 * If event is enabled and currently active on a CPU, update the
4598 * value in the event structure:
4601 if (state == PERF_EVENT_STATE_ACTIVE) {
4602 struct perf_read_data data;
4605 * Orders the ->state and ->oncpu loads such that if we see
4606 * ACTIVE we must also see the right ->oncpu.
4608 * Matches the smp_wmb() from event_sched_in().
4612 event_cpu = READ_ONCE(event->oncpu);
4613 if ((unsigned)event_cpu >= nr_cpu_ids)
4616 data = (struct perf_read_data){
4623 event_cpu = __perf_event_read_cpu(event, event_cpu);
4626 * Purposely ignore the smp_call_function_single() return
4629 * If event_cpu isn't a valid CPU it means the event got
4630 * scheduled out and that will have updated the event count.
4632 * Therefore, either way, we'll have an up-to-date event count
4635 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4639 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4640 struct perf_event_context *ctx = event->ctx;
4641 unsigned long flags;
4643 raw_spin_lock_irqsave(&ctx->lock, flags);
4644 state = event->state;
4645 if (state != PERF_EVENT_STATE_INACTIVE) {
4646 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4651 * May read while context is not active (e.g., thread is
4652 * blocked), in that case we cannot update context time
4654 if (ctx->is_active & EVENT_TIME) {
4655 update_context_time(ctx);
4656 update_cgrp_time_from_event(event);
4659 perf_event_update_time(event);
4661 perf_event_update_sibling_time(event);
4662 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4669 * Initialize the perf_event context in a task_struct:
4671 static void __perf_event_init_context(struct perf_event_context *ctx)
4673 raw_spin_lock_init(&ctx->lock);
4674 mutex_init(&ctx->mutex);
4675 INIT_LIST_HEAD(&ctx->pmu_ctx_list);
4676 perf_event_groups_init(&ctx->pinned_groups);
4677 perf_event_groups_init(&ctx->flexible_groups);
4678 INIT_LIST_HEAD(&ctx->event_list);
4679 refcount_set(&ctx->refcount, 1);
4683 __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu)
4686 INIT_LIST_HEAD(&epc->pmu_ctx_entry);
4687 INIT_LIST_HEAD(&epc->pinned_active);
4688 INIT_LIST_HEAD(&epc->flexible_active);
4689 atomic_set(&epc->refcount, 1);
4692 static struct perf_event_context *
4693 alloc_perf_context(struct task_struct *task)
4695 struct perf_event_context *ctx;
4697 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4701 __perf_event_init_context(ctx);
4703 ctx->task = get_task_struct(task);
4708 static struct task_struct *
4709 find_lively_task_by_vpid(pid_t vpid)
4711 struct task_struct *task;
4717 task = find_task_by_vpid(vpid);
4719 get_task_struct(task);
4723 return ERR_PTR(-ESRCH);
4729 * Returns a matching context with refcount and pincount.
4731 static struct perf_event_context *
4732 find_get_context(struct task_struct *task, struct perf_event *event)
4734 struct perf_event_context *ctx, *clone_ctx = NULL;
4735 struct perf_cpu_context *cpuctx;
4736 unsigned long flags;
4740 /* Must be root to operate on a CPU event: */
4741 err = perf_allow_cpu(&event->attr);
4743 return ERR_PTR(err);
4745 cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
4748 raw_spin_lock_irqsave(&ctx->lock, flags);
4750 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4757 ctx = perf_lock_task_context(task, &flags);
4759 clone_ctx = unclone_ctx(ctx);
4762 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4767 ctx = alloc_perf_context(task);
4773 mutex_lock(&task->perf_event_mutex);
4775 * If it has already passed perf_event_exit_task().
4776 * we must see PF_EXITING, it takes this mutex too.
4778 if (task->flags & PF_EXITING)
4780 else if (task->perf_event_ctxp)
4785 rcu_assign_pointer(task->perf_event_ctxp, ctx);
4787 mutex_unlock(&task->perf_event_mutex);
4789 if (unlikely(err)) {
4801 return ERR_PTR(err);
4804 static struct perf_event_pmu_context *
4805 find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx,
4806 struct perf_event *event)
4808 struct perf_event_pmu_context *new = NULL, *epc;
4809 void *task_ctx_data = NULL;
4812 struct perf_cpu_pmu_context *cpc;
4814 cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu);
4816 raw_spin_lock_irq(&ctx->lock);
4818 atomic_set(&epc->refcount, 1);
4820 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4823 WARN_ON_ONCE(epc->ctx != ctx);
4824 atomic_inc(&epc->refcount);
4826 raw_spin_unlock_irq(&ctx->lock);
4830 new = kzalloc(sizeof(*epc), GFP_KERNEL);
4832 return ERR_PTR(-ENOMEM);
4834 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4835 task_ctx_data = alloc_task_ctx_data(pmu);
4836 if (!task_ctx_data) {
4838 return ERR_PTR(-ENOMEM);
4842 __perf_init_event_pmu_context(new, pmu);
4847 * lockdep_assert_held(&ctx->mutex);
4849 * can't because perf_event_init_task() doesn't actually hold the
4853 raw_spin_lock_irq(&ctx->lock);
4854 list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) {
4855 if (epc->pmu == pmu) {
4856 WARN_ON_ONCE(epc->ctx != ctx);
4857 atomic_inc(&epc->refcount);
4865 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4869 if (task_ctx_data && !epc->task_ctx_data) {
4870 epc->task_ctx_data = task_ctx_data;
4871 task_ctx_data = NULL;
4872 ctx->nr_task_data++;
4874 raw_spin_unlock_irq(&ctx->lock);
4876 free_task_ctx_data(pmu, task_ctx_data);
4882 static void get_pmu_ctx(struct perf_event_pmu_context *epc)
4884 WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount));
4887 static void free_epc_rcu(struct rcu_head *head)
4889 struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head);
4891 kfree(epc->task_ctx_data);
4895 static void put_pmu_ctx(struct perf_event_pmu_context *epc)
4897 struct perf_event_context *ctx = epc->ctx;
4898 unsigned long flags;
4903 * lockdep_assert_held(&ctx->mutex);
4905 * can't because of the call-site in _free_event()/put_event()
4906 * which isn't always called under ctx->mutex.
4908 if (!atomic_dec_and_raw_lock_irqsave(&epc->refcount, &ctx->lock, flags))
4911 WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry));
4913 list_del_init(&epc->pmu_ctx_entry);
4916 WARN_ON_ONCE(!list_empty(&epc->pinned_active));
4917 WARN_ON_ONCE(!list_empty(&epc->flexible_active));
4919 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4924 call_rcu(&epc->rcu_head, free_epc_rcu);
4927 static void perf_event_free_filter(struct perf_event *event);
4929 static void free_event_rcu(struct rcu_head *head)
4931 struct perf_event *event = container_of(head, typeof(*event), rcu_head);
4934 put_pid_ns(event->ns);
4935 perf_event_free_filter(event);
4936 kmem_cache_free(perf_event_cache, event);
4939 static void ring_buffer_attach(struct perf_event *event,
4940 struct perf_buffer *rb);
4942 static void detach_sb_event(struct perf_event *event)
4944 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4946 raw_spin_lock(&pel->lock);
4947 list_del_rcu(&event->sb_list);
4948 raw_spin_unlock(&pel->lock);
4951 static bool is_sb_event(struct perf_event *event)
4953 struct perf_event_attr *attr = &event->attr;
4958 if (event->attach_state & PERF_ATTACH_TASK)
4961 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4962 attr->comm || attr->comm_exec ||
4963 attr->task || attr->ksymbol ||
4964 attr->context_switch || attr->text_poke ||
4970 static void unaccount_pmu_sb_event(struct perf_event *event)
4972 if (is_sb_event(event))
4973 detach_sb_event(event);
4976 #ifdef CONFIG_NO_HZ_FULL
4977 static DEFINE_SPINLOCK(nr_freq_lock);
4980 static void unaccount_freq_event_nohz(void)
4982 #ifdef CONFIG_NO_HZ_FULL
4983 spin_lock(&nr_freq_lock);
4984 if (atomic_dec_and_test(&nr_freq_events))
4985 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4986 spin_unlock(&nr_freq_lock);
4990 static void unaccount_freq_event(void)
4992 if (tick_nohz_full_enabled())
4993 unaccount_freq_event_nohz();
4995 atomic_dec(&nr_freq_events);
4998 static void unaccount_event(struct perf_event *event)
5005 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
5007 if (event->attr.mmap || event->attr.mmap_data)
5008 atomic_dec(&nr_mmap_events);
5009 if (event->attr.build_id)
5010 atomic_dec(&nr_build_id_events);
5011 if (event->attr.comm)
5012 atomic_dec(&nr_comm_events);
5013 if (event->attr.namespaces)
5014 atomic_dec(&nr_namespaces_events);
5015 if (event->attr.cgroup)
5016 atomic_dec(&nr_cgroup_events);
5017 if (event->attr.task)
5018 atomic_dec(&nr_task_events);
5019 if (event->attr.freq)
5020 unaccount_freq_event();
5021 if (event->attr.context_switch) {
5023 atomic_dec(&nr_switch_events);
5025 if (is_cgroup_event(event))
5027 if (has_branch_stack(event))
5029 if (event->attr.ksymbol)
5030 atomic_dec(&nr_ksymbol_events);
5031 if (event->attr.bpf_event)
5032 atomic_dec(&nr_bpf_events);
5033 if (event->attr.text_poke)
5034 atomic_dec(&nr_text_poke_events);
5037 if (!atomic_add_unless(&perf_sched_count, -1, 1))
5038 schedule_delayed_work(&perf_sched_work, HZ);
5041 unaccount_pmu_sb_event(event);
5044 static void perf_sched_delayed(struct work_struct *work)
5046 mutex_lock(&perf_sched_mutex);
5047 if (atomic_dec_and_test(&perf_sched_count))
5048 static_branch_disable(&perf_sched_events);
5049 mutex_unlock(&perf_sched_mutex);
5053 * The following implement mutual exclusion of events on "exclusive" pmus
5054 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
5055 * at a time, so we disallow creating events that might conflict, namely:
5057 * 1) cpu-wide events in the presence of per-task events,
5058 * 2) per-task events in the presence of cpu-wide events,
5059 * 3) two matching events on the same perf_event_context.
5061 * The former two cases are handled in the allocation path (perf_event_alloc(),
5062 * _free_event()), the latter -- before the first perf_install_in_context().
5064 static int exclusive_event_init(struct perf_event *event)
5066 struct pmu *pmu = event->pmu;
5068 if (!is_exclusive_pmu(pmu))
5072 * Prevent co-existence of per-task and cpu-wide events on the
5073 * same exclusive pmu.
5075 * Negative pmu::exclusive_cnt means there are cpu-wide
5076 * events on this "exclusive" pmu, positive means there are
5079 * Since this is called in perf_event_alloc() path, event::ctx
5080 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
5081 * to mean "per-task event", because unlike other attach states it
5082 * never gets cleared.
5084 if (event->attach_state & PERF_ATTACH_TASK) {
5085 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
5088 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
5095 static void exclusive_event_destroy(struct perf_event *event)
5097 struct pmu *pmu = event->pmu;
5099 if (!is_exclusive_pmu(pmu))
5102 /* see comment in exclusive_event_init() */
5103 if (event->attach_state & PERF_ATTACH_TASK)
5104 atomic_dec(&pmu->exclusive_cnt);
5106 atomic_inc(&pmu->exclusive_cnt);
5109 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
5111 if ((e1->pmu == e2->pmu) &&
5112 (e1->cpu == e2->cpu ||
5119 static bool exclusive_event_installable(struct perf_event *event,
5120 struct perf_event_context *ctx)
5122 struct perf_event *iter_event;
5123 struct pmu *pmu = event->pmu;
5125 lockdep_assert_held(&ctx->mutex);
5127 if (!is_exclusive_pmu(pmu))
5130 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5131 if (exclusive_event_match(iter_event, event))
5138 static void perf_addr_filters_splice(struct perf_event *event,
5139 struct list_head *head);
5141 static void _free_event(struct perf_event *event)
5143 irq_work_sync(&event->pending_irq);
5145 unaccount_event(event);
5147 security_perf_event_free(event);
5151 * Can happen when we close an event with re-directed output.
5153 * Since we have a 0 refcount, perf_mmap_close() will skip
5154 * over us; possibly making our ring_buffer_put() the last.
5156 mutex_lock(&event->mmap_mutex);
5157 ring_buffer_attach(event, NULL);
5158 mutex_unlock(&event->mmap_mutex);
5161 if (is_cgroup_event(event))
5162 perf_detach_cgroup(event);
5164 if (!event->parent) {
5165 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5166 put_callchain_buffers();
5169 perf_event_free_bpf_prog(event);
5170 perf_addr_filters_splice(event, NULL);
5171 kfree(event->addr_filter_ranges);
5174 event->destroy(event);
5177 * Must be after ->destroy(), due to uprobe_perf_close() using
5180 if (event->hw.target)
5181 put_task_struct(event->hw.target);
5184 put_pmu_ctx(event->pmu_ctx);
5187 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5188 * all task references must be cleaned up.
5191 put_ctx(event->ctx);
5193 exclusive_event_destroy(event);
5194 module_put(event->pmu->module);
5196 call_rcu(&event->rcu_head, free_event_rcu);
5200 * Used to free events which have a known refcount of 1, such as in error paths
5201 * where the event isn't exposed yet and inherited events.
5203 static void free_event(struct perf_event *event)
5205 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5206 "unexpected event refcount: %ld; ptr=%p\n",
5207 atomic_long_read(&event->refcount), event)) {
5208 /* leak to avoid use-after-free */
5216 * Remove user event from the owner task.
5218 static void perf_remove_from_owner(struct perf_event *event)
5220 struct task_struct *owner;
5224 * Matches the smp_store_release() in perf_event_exit_task(). If we
5225 * observe !owner it means the list deletion is complete and we can
5226 * indeed free this event, otherwise we need to serialize on
5227 * owner->perf_event_mutex.
5229 owner = READ_ONCE(event->owner);
5232 * Since delayed_put_task_struct() also drops the last
5233 * task reference we can safely take a new reference
5234 * while holding the rcu_read_lock().
5236 get_task_struct(owner);
5242 * If we're here through perf_event_exit_task() we're already
5243 * holding ctx->mutex which would be an inversion wrt. the
5244 * normal lock order.
5246 * However we can safely take this lock because its the child
5249 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5252 * We have to re-check the event->owner field, if it is cleared
5253 * we raced with perf_event_exit_task(), acquiring the mutex
5254 * ensured they're done, and we can proceed with freeing the
5258 list_del_init(&event->owner_entry);
5259 smp_store_release(&event->owner, NULL);
5261 mutex_unlock(&owner->perf_event_mutex);
5262 put_task_struct(owner);
5266 static void put_event(struct perf_event *event)
5268 if (!atomic_long_dec_and_test(&event->refcount))
5275 * Kill an event dead; while event:refcount will preserve the event
5276 * object, it will not preserve its functionality. Once the last 'user'
5277 * gives up the object, we'll destroy the thing.
5279 int perf_event_release_kernel(struct perf_event *event)
5281 struct perf_event_context *ctx = event->ctx;
5282 struct perf_event *child, *tmp;
5283 LIST_HEAD(free_list);
5286 * If we got here through err_alloc: free_event(event); we will not
5287 * have attached to a context yet.
5290 WARN_ON_ONCE(event->attach_state &
5291 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5295 if (!is_kernel_event(event))
5296 perf_remove_from_owner(event);
5298 ctx = perf_event_ctx_lock(event);
5299 WARN_ON_ONCE(ctx->parent_ctx);
5302 * Mark this event as STATE_DEAD, there is no external reference to it
5305 * Anybody acquiring event->child_mutex after the below loop _must_
5306 * also see this, most importantly inherit_event() which will avoid
5307 * placing more children on the list.
5309 * Thus this guarantees that we will in fact observe and kill _ALL_
5312 perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD);
5314 perf_event_ctx_unlock(event, ctx);
5317 mutex_lock(&event->child_mutex);
5318 list_for_each_entry(child, &event->child_list, child_list) {
5321 * Cannot change, child events are not migrated, see the
5322 * comment with perf_event_ctx_lock_nested().
5324 ctx = READ_ONCE(child->ctx);
5326 * Since child_mutex nests inside ctx::mutex, we must jump
5327 * through hoops. We start by grabbing a reference on the ctx.
5329 * Since the event cannot get freed while we hold the
5330 * child_mutex, the context must also exist and have a !0
5336 * Now that we have a ctx ref, we can drop child_mutex, and
5337 * acquire ctx::mutex without fear of it going away. Then we
5338 * can re-acquire child_mutex.
5340 mutex_unlock(&event->child_mutex);
5341 mutex_lock(&ctx->mutex);
5342 mutex_lock(&event->child_mutex);
5345 * Now that we hold ctx::mutex and child_mutex, revalidate our
5346 * state, if child is still the first entry, it didn't get freed
5347 * and we can continue doing so.
5349 tmp = list_first_entry_or_null(&event->child_list,
5350 struct perf_event, child_list);
5352 perf_remove_from_context(child, DETACH_GROUP);
5353 list_move(&child->child_list, &free_list);
5355 * This matches the refcount bump in inherit_event();
5356 * this can't be the last reference.
5361 mutex_unlock(&event->child_mutex);
5362 mutex_unlock(&ctx->mutex);
5366 mutex_unlock(&event->child_mutex);
5368 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5369 void *var = &child->ctx->refcount;
5371 list_del(&child->child_list);
5375 * Wake any perf_event_free_task() waiting for this event to be
5378 smp_mb(); /* pairs with wait_var_event() */
5383 put_event(event); /* Must be the 'last' reference */
5386 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5389 * Called when the last reference to the file is gone.
5391 static int perf_release(struct inode *inode, struct file *file)
5393 perf_event_release_kernel(file->private_data);
5397 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5399 struct perf_event *child;
5405 mutex_lock(&event->child_mutex);
5407 (void)perf_event_read(event, false);
5408 total += perf_event_count(event);
5410 *enabled += event->total_time_enabled +
5411 atomic64_read(&event->child_total_time_enabled);
5412 *running += event->total_time_running +
5413 atomic64_read(&event->child_total_time_running);
5415 list_for_each_entry(child, &event->child_list, child_list) {
5416 (void)perf_event_read(child, false);
5417 total += perf_event_count(child);
5418 *enabled += child->total_time_enabled;
5419 *running += child->total_time_running;
5421 mutex_unlock(&event->child_mutex);
5426 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5428 struct perf_event_context *ctx;
5431 ctx = perf_event_ctx_lock(event);
5432 count = __perf_event_read_value(event, enabled, running);
5433 perf_event_ctx_unlock(event, ctx);
5437 EXPORT_SYMBOL_GPL(perf_event_read_value);
5439 static int __perf_read_group_add(struct perf_event *leader,
5440 u64 read_format, u64 *values)
5442 struct perf_event_context *ctx = leader->ctx;
5443 struct perf_event *sub;
5444 unsigned long flags;
5445 int n = 1; /* skip @nr */
5448 ret = perf_event_read(leader, true);
5452 raw_spin_lock_irqsave(&ctx->lock, flags);
5455 * Since we co-schedule groups, {enabled,running} times of siblings
5456 * will be identical to those of the leader, so we only publish one
5459 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5460 values[n++] += leader->total_time_enabled +
5461 atomic64_read(&leader->child_total_time_enabled);
5464 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5465 values[n++] += leader->total_time_running +
5466 atomic64_read(&leader->child_total_time_running);
5470 * Write {count,id} tuples for every sibling.
5472 values[n++] += perf_event_count(leader);
5473 if (read_format & PERF_FORMAT_ID)
5474 values[n++] = primary_event_id(leader);
5475 if (read_format & PERF_FORMAT_LOST)
5476 values[n++] = atomic64_read(&leader->lost_samples);
5478 for_each_sibling_event(sub, leader) {
5479 values[n++] += perf_event_count(sub);
5480 if (read_format & PERF_FORMAT_ID)
5481 values[n++] = primary_event_id(sub);
5482 if (read_format & PERF_FORMAT_LOST)
5483 values[n++] = atomic64_read(&sub->lost_samples);
5486 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5490 static int perf_read_group(struct perf_event *event,
5491 u64 read_format, char __user *buf)
5493 struct perf_event *leader = event->group_leader, *child;
5494 struct perf_event_context *ctx = leader->ctx;
5498 lockdep_assert_held(&ctx->mutex);
5500 values = kzalloc(event->read_size, GFP_KERNEL);
5504 values[0] = 1 + leader->nr_siblings;
5507 * By locking the child_mutex of the leader we effectively
5508 * lock the child list of all siblings.. XXX explain how.
5510 mutex_lock(&leader->child_mutex);
5512 ret = __perf_read_group_add(leader, read_format, values);
5516 list_for_each_entry(child, &leader->child_list, child_list) {
5517 ret = __perf_read_group_add(child, read_format, values);
5522 mutex_unlock(&leader->child_mutex);
5524 ret = event->read_size;
5525 if (copy_to_user(buf, values, event->read_size))
5530 mutex_unlock(&leader->child_mutex);
5536 static int perf_read_one(struct perf_event *event,
5537 u64 read_format, char __user *buf)
5539 u64 enabled, running;
5543 values[n++] = __perf_event_read_value(event, &enabled, &running);
5544 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5545 values[n++] = enabled;
5546 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5547 values[n++] = running;
5548 if (read_format & PERF_FORMAT_ID)
5549 values[n++] = primary_event_id(event);
5550 if (read_format & PERF_FORMAT_LOST)
5551 values[n++] = atomic64_read(&event->lost_samples);
5553 if (copy_to_user(buf, values, n * sizeof(u64)))
5556 return n * sizeof(u64);
5559 static bool is_event_hup(struct perf_event *event)
5563 if (event->state > PERF_EVENT_STATE_EXIT)
5566 mutex_lock(&event->child_mutex);
5567 no_children = list_empty(&event->child_list);
5568 mutex_unlock(&event->child_mutex);
5573 * Read the performance event - simple non blocking version for now
5576 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5578 u64 read_format = event->attr.read_format;
5582 * Return end-of-file for a read on an event that is in
5583 * error state (i.e. because it was pinned but it couldn't be
5584 * scheduled on to the CPU at some point).
5586 if (event->state == PERF_EVENT_STATE_ERROR)
5589 if (count < event->read_size)
5592 WARN_ON_ONCE(event->ctx->parent_ctx);
5593 if (read_format & PERF_FORMAT_GROUP)
5594 ret = perf_read_group(event, read_format, buf);
5596 ret = perf_read_one(event, read_format, buf);
5602 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5604 struct perf_event *event = file->private_data;
5605 struct perf_event_context *ctx;
5608 ret = security_perf_event_read(event);
5612 ctx = perf_event_ctx_lock(event);
5613 ret = __perf_read(event, buf, count);
5614 perf_event_ctx_unlock(event, ctx);
5619 static __poll_t perf_poll(struct file *file, poll_table *wait)
5621 struct perf_event *event = file->private_data;
5622 struct perf_buffer *rb;
5623 __poll_t events = EPOLLHUP;
5625 poll_wait(file, &event->waitq, wait);
5627 if (is_event_hup(event))
5631 * Pin the event->rb by taking event->mmap_mutex; otherwise
5632 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5634 mutex_lock(&event->mmap_mutex);
5637 events = atomic_xchg(&rb->poll, 0);
5638 mutex_unlock(&event->mmap_mutex);
5642 static void _perf_event_reset(struct perf_event *event)
5644 (void)perf_event_read(event, false);
5645 local64_set(&event->count, 0);
5646 perf_event_update_userpage(event);
5649 /* Assume it's not an event with inherit set. */
5650 u64 perf_event_pause(struct perf_event *event, bool reset)
5652 struct perf_event_context *ctx;
5655 ctx = perf_event_ctx_lock(event);
5656 WARN_ON_ONCE(event->attr.inherit);
5657 _perf_event_disable(event);
5658 count = local64_read(&event->count);
5660 local64_set(&event->count, 0);
5661 perf_event_ctx_unlock(event, ctx);
5665 EXPORT_SYMBOL_GPL(perf_event_pause);
5668 * Holding the top-level event's child_mutex means that any
5669 * descendant process that has inherited this event will block
5670 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5671 * task existence requirements of perf_event_enable/disable.
5673 static void perf_event_for_each_child(struct perf_event *event,
5674 void (*func)(struct perf_event *))
5676 struct perf_event *child;
5678 WARN_ON_ONCE(event->ctx->parent_ctx);
5680 mutex_lock(&event->child_mutex);
5682 list_for_each_entry(child, &event->child_list, child_list)
5684 mutex_unlock(&event->child_mutex);
5687 static void perf_event_for_each(struct perf_event *event,
5688 void (*func)(struct perf_event *))
5690 struct perf_event_context *ctx = event->ctx;
5691 struct perf_event *sibling;
5693 lockdep_assert_held(&ctx->mutex);
5695 event = event->group_leader;
5697 perf_event_for_each_child(event, func);
5698 for_each_sibling_event(sibling, event)
5699 perf_event_for_each_child(sibling, func);
5702 static void __perf_event_period(struct perf_event *event,
5703 struct perf_cpu_context *cpuctx,
5704 struct perf_event_context *ctx,
5707 u64 value = *((u64 *)info);
5710 if (event->attr.freq) {
5711 event->attr.sample_freq = value;
5713 event->attr.sample_period = value;
5714 event->hw.sample_period = value;
5717 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5719 perf_pmu_disable(event->pmu);
5721 * We could be throttled; unthrottle now to avoid the tick
5722 * trying to unthrottle while we already re-started the event.
5724 if (event->hw.interrupts == MAX_INTERRUPTS) {
5725 event->hw.interrupts = 0;
5726 perf_log_throttle(event, 1);
5728 event->pmu->stop(event, PERF_EF_UPDATE);
5731 local64_set(&event->hw.period_left, 0);
5734 event->pmu->start(event, PERF_EF_RELOAD);
5735 perf_pmu_enable(event->pmu);
5739 static int perf_event_check_period(struct perf_event *event, u64 value)
5741 return event->pmu->check_period(event, value);
5744 static int _perf_event_period(struct perf_event *event, u64 value)
5746 if (!is_sampling_event(event))
5752 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5755 if (perf_event_check_period(event, value))
5758 if (!event->attr.freq && (value & (1ULL << 63)))
5761 event_function_call(event, __perf_event_period, &value);
5766 int perf_event_period(struct perf_event *event, u64 value)
5768 struct perf_event_context *ctx;
5771 ctx = perf_event_ctx_lock(event);
5772 ret = _perf_event_period(event, value);
5773 perf_event_ctx_unlock(event, ctx);
5777 EXPORT_SYMBOL_GPL(perf_event_period);
5779 static const struct file_operations perf_fops;
5781 static inline int perf_fget_light(int fd, struct fd *p)
5783 struct fd f = fdget(fd);
5787 if (f.file->f_op != &perf_fops) {
5795 static int perf_event_set_output(struct perf_event *event,
5796 struct perf_event *output_event);
5797 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5798 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5799 struct perf_event_attr *attr);
5801 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5803 void (*func)(struct perf_event *);
5807 case PERF_EVENT_IOC_ENABLE:
5808 func = _perf_event_enable;
5810 case PERF_EVENT_IOC_DISABLE:
5811 func = _perf_event_disable;
5813 case PERF_EVENT_IOC_RESET:
5814 func = _perf_event_reset;
5817 case PERF_EVENT_IOC_REFRESH:
5818 return _perf_event_refresh(event, arg);
5820 case PERF_EVENT_IOC_PERIOD:
5824 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5827 return _perf_event_period(event, value);
5829 case PERF_EVENT_IOC_ID:
5831 u64 id = primary_event_id(event);
5833 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5838 case PERF_EVENT_IOC_SET_OUTPUT:
5842 struct perf_event *output_event;
5844 ret = perf_fget_light(arg, &output);
5847 output_event = output.file->private_data;
5848 ret = perf_event_set_output(event, output_event);
5851 ret = perf_event_set_output(event, NULL);
5856 case PERF_EVENT_IOC_SET_FILTER:
5857 return perf_event_set_filter(event, (void __user *)arg);
5859 case PERF_EVENT_IOC_SET_BPF:
5861 struct bpf_prog *prog;
5864 prog = bpf_prog_get(arg);
5866 return PTR_ERR(prog);
5868 err = perf_event_set_bpf_prog(event, prog, 0);
5877 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5878 struct perf_buffer *rb;
5881 rb = rcu_dereference(event->rb);
5882 if (!rb || !rb->nr_pages) {
5886 rb_toggle_paused(rb, !!arg);
5891 case PERF_EVENT_IOC_QUERY_BPF:
5892 return perf_event_query_prog_array(event, (void __user *)arg);
5894 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5895 struct perf_event_attr new_attr;
5896 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5902 return perf_event_modify_attr(event, &new_attr);
5908 if (flags & PERF_IOC_FLAG_GROUP)
5909 perf_event_for_each(event, func);
5911 perf_event_for_each_child(event, func);
5916 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5918 struct perf_event *event = file->private_data;
5919 struct perf_event_context *ctx;
5922 /* Treat ioctl like writes as it is likely a mutating operation. */
5923 ret = security_perf_event_write(event);
5927 ctx = perf_event_ctx_lock(event);
5928 ret = _perf_ioctl(event, cmd, arg);
5929 perf_event_ctx_unlock(event, ctx);
5934 #ifdef CONFIG_COMPAT
5935 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5938 switch (_IOC_NR(cmd)) {
5939 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5940 case _IOC_NR(PERF_EVENT_IOC_ID):
5941 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5942 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5943 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5944 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5945 cmd &= ~IOCSIZE_MASK;
5946 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5950 return perf_ioctl(file, cmd, arg);
5953 # define perf_compat_ioctl NULL
5956 int perf_event_task_enable(void)
5958 struct perf_event_context *ctx;
5959 struct perf_event *event;
5961 mutex_lock(¤t->perf_event_mutex);
5962 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5963 ctx = perf_event_ctx_lock(event);
5964 perf_event_for_each_child(event, _perf_event_enable);
5965 perf_event_ctx_unlock(event, ctx);
5967 mutex_unlock(¤t->perf_event_mutex);
5972 int perf_event_task_disable(void)
5974 struct perf_event_context *ctx;
5975 struct perf_event *event;
5977 mutex_lock(¤t->perf_event_mutex);
5978 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5979 ctx = perf_event_ctx_lock(event);
5980 perf_event_for_each_child(event, _perf_event_disable);
5981 perf_event_ctx_unlock(event, ctx);
5983 mutex_unlock(¤t->perf_event_mutex);
5988 static int perf_event_index(struct perf_event *event)
5990 if (event->hw.state & PERF_HES_STOPPED)
5993 if (event->state != PERF_EVENT_STATE_ACTIVE)
5996 return event->pmu->event_idx(event);
5999 static void perf_event_init_userpage(struct perf_event *event)
6001 struct perf_event_mmap_page *userpg;
6002 struct perf_buffer *rb;
6005 rb = rcu_dereference(event->rb);
6009 userpg = rb->user_page;
6011 /* Allow new userspace to detect that bit 0 is deprecated */
6012 userpg->cap_bit0_is_deprecated = 1;
6013 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
6014 userpg->data_offset = PAGE_SIZE;
6015 userpg->data_size = perf_data_size(rb);
6021 void __weak arch_perf_update_userpage(
6022 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
6027 * Callers need to ensure there can be no nesting of this function, otherwise
6028 * the seqlock logic goes bad. We can not serialize this because the arch
6029 * code calls this from NMI context.
6031 void perf_event_update_userpage(struct perf_event *event)
6033 struct perf_event_mmap_page *userpg;
6034 struct perf_buffer *rb;
6035 u64 enabled, running, now;
6038 rb = rcu_dereference(event->rb);
6043 * compute total_time_enabled, total_time_running
6044 * based on snapshot values taken when the event
6045 * was last scheduled in.
6047 * we cannot simply called update_context_time()
6048 * because of locking issue as we can be called in
6051 calc_timer_values(event, &now, &enabled, &running);
6053 userpg = rb->user_page;
6055 * Disable preemption to guarantee consistent time stamps are stored to
6061 userpg->index = perf_event_index(event);
6062 userpg->offset = perf_event_count(event);
6064 userpg->offset -= local64_read(&event->hw.prev_count);
6066 userpg->time_enabled = enabled +
6067 atomic64_read(&event->child_total_time_enabled);
6069 userpg->time_running = running +
6070 atomic64_read(&event->child_total_time_running);
6072 arch_perf_update_userpage(event, userpg, now);
6080 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
6082 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
6084 struct perf_event *event = vmf->vma->vm_file->private_data;
6085 struct perf_buffer *rb;
6086 vm_fault_t ret = VM_FAULT_SIGBUS;
6088 if (vmf->flags & FAULT_FLAG_MKWRITE) {
6089 if (vmf->pgoff == 0)
6095 rb = rcu_dereference(event->rb);
6099 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
6102 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
6106 get_page(vmf->page);
6107 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
6108 vmf->page->index = vmf->pgoff;
6117 static void ring_buffer_attach(struct perf_event *event,
6118 struct perf_buffer *rb)
6120 struct perf_buffer *old_rb = NULL;
6121 unsigned long flags;
6123 WARN_ON_ONCE(event->parent);
6127 * Should be impossible, we set this when removing
6128 * event->rb_entry and wait/clear when adding event->rb_entry.
6130 WARN_ON_ONCE(event->rcu_pending);
6133 spin_lock_irqsave(&old_rb->event_lock, flags);
6134 list_del_rcu(&event->rb_entry);
6135 spin_unlock_irqrestore(&old_rb->event_lock, flags);
6137 event->rcu_batches = get_state_synchronize_rcu();
6138 event->rcu_pending = 1;
6142 if (event->rcu_pending) {
6143 cond_synchronize_rcu(event->rcu_batches);
6144 event->rcu_pending = 0;
6147 spin_lock_irqsave(&rb->event_lock, flags);
6148 list_add_rcu(&event->rb_entry, &rb->event_list);
6149 spin_unlock_irqrestore(&rb->event_lock, flags);
6153 * Avoid racing with perf_mmap_close(AUX): stop the event
6154 * before swizzling the event::rb pointer; if it's getting
6155 * unmapped, its aux_mmap_count will be 0 and it won't
6156 * restart. See the comment in __perf_pmu_output_stop().
6158 * Data will inevitably be lost when set_output is done in
6159 * mid-air, but then again, whoever does it like this is
6160 * not in for the data anyway.
6163 perf_event_stop(event, 0);
6165 rcu_assign_pointer(event->rb, rb);
6168 ring_buffer_put(old_rb);
6170 * Since we detached before setting the new rb, so that we
6171 * could attach the new rb, we could have missed a wakeup.
6174 wake_up_all(&event->waitq);
6178 static void ring_buffer_wakeup(struct perf_event *event)
6180 struct perf_buffer *rb;
6183 event = event->parent;
6186 rb = rcu_dereference(event->rb);
6188 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6189 wake_up_all(&event->waitq);
6194 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6196 struct perf_buffer *rb;
6199 event = event->parent;
6202 rb = rcu_dereference(event->rb);
6204 if (!refcount_inc_not_zero(&rb->refcount))
6212 void ring_buffer_put(struct perf_buffer *rb)
6214 if (!refcount_dec_and_test(&rb->refcount))
6217 WARN_ON_ONCE(!list_empty(&rb->event_list));
6219 call_rcu(&rb->rcu_head, rb_free_rcu);
6222 static void perf_mmap_open(struct vm_area_struct *vma)
6224 struct perf_event *event = vma->vm_file->private_data;
6226 atomic_inc(&event->mmap_count);
6227 atomic_inc(&event->rb->mmap_count);
6230 atomic_inc(&event->rb->aux_mmap_count);
6232 if (event->pmu->event_mapped)
6233 event->pmu->event_mapped(event, vma->vm_mm);
6236 static void perf_pmu_output_stop(struct perf_event *event);
6239 * A buffer can be mmap()ed multiple times; either directly through the same
6240 * event, or through other events by use of perf_event_set_output().
6242 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6243 * the buffer here, where we still have a VM context. This means we need
6244 * to detach all events redirecting to us.
6246 static void perf_mmap_close(struct vm_area_struct *vma)
6248 struct perf_event *event = vma->vm_file->private_data;
6249 struct perf_buffer *rb = ring_buffer_get(event);
6250 struct user_struct *mmap_user = rb->mmap_user;
6251 int mmap_locked = rb->mmap_locked;
6252 unsigned long size = perf_data_size(rb);
6253 bool detach_rest = false;
6255 if (event->pmu->event_unmapped)
6256 event->pmu->event_unmapped(event, vma->vm_mm);
6259 * rb->aux_mmap_count will always drop before rb->mmap_count and
6260 * event->mmap_count, so it is ok to use event->mmap_mutex to
6261 * serialize with perf_mmap here.
6263 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6264 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6266 * Stop all AUX events that are writing to this buffer,
6267 * so that we can free its AUX pages and corresponding PMU
6268 * data. Note that after rb::aux_mmap_count dropped to zero,
6269 * they won't start any more (see perf_aux_output_begin()).
6271 perf_pmu_output_stop(event);
6273 /* now it's safe to free the pages */
6274 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6275 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6277 /* this has to be the last one */
6279 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6281 mutex_unlock(&event->mmap_mutex);
6284 if (atomic_dec_and_test(&rb->mmap_count))
6287 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6290 ring_buffer_attach(event, NULL);
6291 mutex_unlock(&event->mmap_mutex);
6293 /* If there's still other mmap()s of this buffer, we're done. */
6298 * No other mmap()s, detach from all other events that might redirect
6299 * into the now unreachable buffer. Somewhat complicated by the
6300 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6304 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6305 if (!atomic_long_inc_not_zero(&event->refcount)) {
6307 * This event is en-route to free_event() which will
6308 * detach it and remove it from the list.
6314 mutex_lock(&event->mmap_mutex);
6316 * Check we didn't race with perf_event_set_output() which can
6317 * swizzle the rb from under us while we were waiting to
6318 * acquire mmap_mutex.
6320 * If we find a different rb; ignore this event, a next
6321 * iteration will no longer find it on the list. We have to
6322 * still restart the iteration to make sure we're not now
6323 * iterating the wrong list.
6325 if (event->rb == rb)
6326 ring_buffer_attach(event, NULL);
6328 mutex_unlock(&event->mmap_mutex);
6332 * Restart the iteration; either we're on the wrong list or
6333 * destroyed its integrity by doing a deletion.
6340 * It could be there's still a few 0-ref events on the list; they'll
6341 * get cleaned up by free_event() -- they'll also still have their
6342 * ref on the rb and will free it whenever they are done with it.
6344 * Aside from that, this buffer is 'fully' detached and unmapped,
6345 * undo the VM accounting.
6348 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6349 &mmap_user->locked_vm);
6350 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6351 free_uid(mmap_user);
6354 ring_buffer_put(rb); /* could be last */
6357 static const struct vm_operations_struct perf_mmap_vmops = {
6358 .open = perf_mmap_open,
6359 .close = perf_mmap_close, /* non mergeable */
6360 .fault = perf_mmap_fault,
6361 .page_mkwrite = perf_mmap_fault,
6364 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6366 struct perf_event *event = file->private_data;
6367 unsigned long user_locked, user_lock_limit;
6368 struct user_struct *user = current_user();
6369 struct perf_buffer *rb = NULL;
6370 unsigned long locked, lock_limit;
6371 unsigned long vma_size;
6372 unsigned long nr_pages;
6373 long user_extra = 0, extra = 0;
6374 int ret = 0, flags = 0;
6377 * Don't allow mmap() of inherited per-task counters. This would
6378 * create a performance issue due to all children writing to the
6381 if (event->cpu == -1 && event->attr.inherit)
6384 if (!(vma->vm_flags & VM_SHARED))
6387 ret = security_perf_event_read(event);
6391 vma_size = vma->vm_end - vma->vm_start;
6393 if (vma->vm_pgoff == 0) {
6394 nr_pages = (vma_size / PAGE_SIZE) - 1;
6397 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6398 * mapped, all subsequent mappings should have the same size
6399 * and offset. Must be above the normal perf buffer.
6401 u64 aux_offset, aux_size;
6406 nr_pages = vma_size / PAGE_SIZE;
6408 mutex_lock(&event->mmap_mutex);
6415 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6416 aux_size = READ_ONCE(rb->user_page->aux_size);
6418 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6421 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6424 /* already mapped with a different offset */
6425 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6428 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6431 /* already mapped with a different size */
6432 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6435 if (!is_power_of_2(nr_pages))
6438 if (!atomic_inc_not_zero(&rb->mmap_count))
6441 if (rb_has_aux(rb)) {
6442 atomic_inc(&rb->aux_mmap_count);
6447 atomic_set(&rb->aux_mmap_count, 1);
6448 user_extra = nr_pages;
6454 * If we have rb pages ensure they're a power-of-two number, so we
6455 * can do bitmasks instead of modulo.
6457 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6460 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6463 WARN_ON_ONCE(event->ctx->parent_ctx);
6465 mutex_lock(&event->mmap_mutex);
6467 if (data_page_nr(event->rb) != nr_pages) {
6472 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6474 * Raced against perf_mmap_close(); remove the
6475 * event and try again.
6477 ring_buffer_attach(event, NULL);
6478 mutex_unlock(&event->mmap_mutex);
6485 user_extra = nr_pages + 1;
6488 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6491 * Increase the limit linearly with more CPUs:
6493 user_lock_limit *= num_online_cpus();
6495 user_locked = atomic_long_read(&user->locked_vm);
6498 * sysctl_perf_event_mlock may have changed, so that
6499 * user->locked_vm > user_lock_limit
6501 if (user_locked > user_lock_limit)
6502 user_locked = user_lock_limit;
6503 user_locked += user_extra;
6505 if (user_locked > user_lock_limit) {
6507 * charge locked_vm until it hits user_lock_limit;
6508 * charge the rest from pinned_vm
6510 extra = user_locked - user_lock_limit;
6511 user_extra -= extra;
6514 lock_limit = rlimit(RLIMIT_MEMLOCK);
6515 lock_limit >>= PAGE_SHIFT;
6516 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6518 if ((locked > lock_limit) && perf_is_paranoid() &&
6519 !capable(CAP_IPC_LOCK)) {
6524 WARN_ON(!rb && event->rb);
6526 if (vma->vm_flags & VM_WRITE)
6527 flags |= RING_BUFFER_WRITABLE;
6530 rb = rb_alloc(nr_pages,
6531 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6539 atomic_set(&rb->mmap_count, 1);
6540 rb->mmap_user = get_current_user();
6541 rb->mmap_locked = extra;
6543 ring_buffer_attach(event, rb);
6545 perf_event_update_time(event);
6546 perf_event_init_userpage(event);
6547 perf_event_update_userpage(event);
6549 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6550 event->attr.aux_watermark, flags);
6552 rb->aux_mmap_locked = extra;
6557 atomic_long_add(user_extra, &user->locked_vm);
6558 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6560 atomic_inc(&event->mmap_count);
6562 atomic_dec(&rb->mmap_count);
6565 mutex_unlock(&event->mmap_mutex);
6568 * Since pinned accounting is per vm we cannot allow fork() to copy our
6571 vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP);
6572 vma->vm_ops = &perf_mmap_vmops;
6574 if (event->pmu->event_mapped)
6575 event->pmu->event_mapped(event, vma->vm_mm);
6580 static int perf_fasync(int fd, struct file *filp, int on)
6582 struct inode *inode = file_inode(filp);
6583 struct perf_event *event = filp->private_data;
6587 retval = fasync_helper(fd, filp, on, &event->fasync);
6588 inode_unlock(inode);
6596 static const struct file_operations perf_fops = {
6597 .llseek = no_llseek,
6598 .release = perf_release,
6601 .unlocked_ioctl = perf_ioctl,
6602 .compat_ioctl = perf_compat_ioctl,
6604 .fasync = perf_fasync,
6610 * If there's data, ensure we set the poll() state and publish everything
6611 * to user-space before waking everybody up.
6614 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6616 /* only the parent has fasync state */
6618 event = event->parent;
6619 return &event->fasync;
6622 void perf_event_wakeup(struct perf_event *event)
6624 ring_buffer_wakeup(event);
6626 if (event->pending_kill) {
6627 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6628 event->pending_kill = 0;
6632 static void perf_sigtrap(struct perf_event *event)
6635 * We'd expect this to only occur if the irq_work is delayed and either
6636 * ctx->task or current has changed in the meantime. This can be the
6637 * case on architectures that do not implement arch_irq_work_raise().
6639 if (WARN_ON_ONCE(event->ctx->task != current))
6643 * Both perf_pending_task() and perf_pending_irq() can race with the
6646 if (current->flags & PF_EXITING)
6649 send_sig_perf((void __user *)event->pending_addr,
6650 event->orig_type, event->attr.sig_data);
6654 * Deliver the pending work in-event-context or follow the context.
6656 static void __perf_pending_irq(struct perf_event *event)
6658 int cpu = READ_ONCE(event->oncpu);
6661 * If the event isn't running; we done. event_sched_out() will have
6662 * taken care of things.
6668 * Yay, we hit home and are in the context of the event.
6670 if (cpu == smp_processor_id()) {
6671 if (event->pending_sigtrap) {
6672 event->pending_sigtrap = 0;
6673 perf_sigtrap(event);
6674 local_dec(&event->ctx->nr_pending);
6676 if (event->pending_disable) {
6677 event->pending_disable = 0;
6678 perf_event_disable_local(event);
6686 * perf_event_disable_inatomic()
6687 * @pending_disable = CPU-A;
6691 * @pending_disable = -1;
6694 * perf_event_disable_inatomic()
6695 * @pending_disable = CPU-B;
6696 * irq_work_queue(); // FAILS
6699 * perf_pending_irq()
6701 * But the event runs on CPU-B and wants disabling there.
6703 irq_work_queue_on(&event->pending_irq, cpu);
6706 static void perf_pending_irq(struct irq_work *entry)
6708 struct perf_event *event = container_of(entry, struct perf_event, pending_irq);
6712 * If we 'fail' here, that's OK, it means recursion is already disabled
6713 * and we won't recurse 'further'.
6715 rctx = perf_swevent_get_recursion_context();
6718 * The wakeup isn't bound to the context of the event -- it can happen
6719 * irrespective of where the event is.
6721 if (event->pending_wakeup) {
6722 event->pending_wakeup = 0;
6723 perf_event_wakeup(event);
6726 __perf_pending_irq(event);
6729 perf_swevent_put_recursion_context(rctx);
6732 static void perf_pending_task(struct callback_head *head)
6734 struct perf_event *event = container_of(head, struct perf_event, pending_task);
6738 * If we 'fail' here, that's OK, it means recursion is already disabled
6739 * and we won't recurse 'further'.
6741 preempt_disable_notrace();
6742 rctx = perf_swevent_get_recursion_context();
6744 if (event->pending_work) {
6745 event->pending_work = 0;
6746 perf_sigtrap(event);
6747 local_dec(&event->ctx->nr_pending);
6751 perf_swevent_put_recursion_context(rctx);
6752 preempt_enable_notrace();
6757 #ifdef CONFIG_GUEST_PERF_EVENTS
6758 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6760 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6761 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6762 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6764 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6766 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6769 rcu_assign_pointer(perf_guest_cbs, cbs);
6770 static_call_update(__perf_guest_state, cbs->state);
6771 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6773 /* Implementing ->handle_intel_pt_intr is optional. */
6774 if (cbs->handle_intel_pt_intr)
6775 static_call_update(__perf_guest_handle_intel_pt_intr,
6776 cbs->handle_intel_pt_intr);
6778 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6780 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6782 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6785 rcu_assign_pointer(perf_guest_cbs, NULL);
6786 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6787 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6788 static_call_update(__perf_guest_handle_intel_pt_intr,
6789 (void *)&__static_call_return0);
6792 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6796 perf_output_sample_regs(struct perf_output_handle *handle,
6797 struct pt_regs *regs, u64 mask)
6800 DECLARE_BITMAP(_mask, 64);
6802 bitmap_from_u64(_mask, mask);
6803 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6806 val = perf_reg_value(regs, bit);
6807 perf_output_put(handle, val);
6811 static void perf_sample_regs_user(struct perf_regs *regs_user,
6812 struct pt_regs *regs)
6814 if (user_mode(regs)) {
6815 regs_user->abi = perf_reg_abi(current);
6816 regs_user->regs = regs;
6817 } else if (!(current->flags & PF_KTHREAD)) {
6818 perf_get_regs_user(regs_user, regs);
6820 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6821 regs_user->regs = NULL;
6825 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6826 struct pt_regs *regs)
6828 regs_intr->regs = regs;
6829 regs_intr->abi = perf_reg_abi(current);
6834 * Get remaining task size from user stack pointer.
6836 * It'd be better to take stack vma map and limit this more
6837 * precisely, but there's no way to get it safely under interrupt,
6838 * so using TASK_SIZE as limit.
6840 static u64 perf_ustack_task_size(struct pt_regs *regs)
6842 unsigned long addr = perf_user_stack_pointer(regs);
6844 if (!addr || addr >= TASK_SIZE)
6847 return TASK_SIZE - addr;
6851 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6852 struct pt_regs *regs)
6856 /* No regs, no stack pointer, no dump. */
6861 * Check if we fit in with the requested stack size into the:
6863 * If we don't, we limit the size to the TASK_SIZE.
6865 * - remaining sample size
6866 * If we don't, we customize the stack size to
6867 * fit in to the remaining sample size.
6870 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6871 stack_size = min(stack_size, (u16) task_size);
6873 /* Current header size plus static size and dynamic size. */
6874 header_size += 2 * sizeof(u64);
6876 /* Do we fit in with the current stack dump size? */
6877 if ((u16) (header_size + stack_size) < header_size) {
6879 * If we overflow the maximum size for the sample,
6880 * we customize the stack dump size to fit in.
6882 stack_size = USHRT_MAX - header_size - sizeof(u64);
6883 stack_size = round_up(stack_size, sizeof(u64));
6890 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6891 struct pt_regs *regs)
6893 /* Case of a kernel thread, nothing to dump */
6896 perf_output_put(handle, size);
6905 * - the size requested by user or the best one we can fit
6906 * in to the sample max size
6908 * - user stack dump data
6910 * - the actual dumped size
6914 perf_output_put(handle, dump_size);
6917 sp = perf_user_stack_pointer(regs);
6918 rem = __output_copy_user(handle, (void *) sp, dump_size);
6919 dyn_size = dump_size - rem;
6921 perf_output_skip(handle, rem);
6924 perf_output_put(handle, dyn_size);
6928 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6929 struct perf_sample_data *data,
6932 struct perf_event *sampler = event->aux_event;
6933 struct perf_buffer *rb;
6940 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6943 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6946 rb = ring_buffer_get(sampler);
6951 * If this is an NMI hit inside sampling code, don't take
6952 * the sample. See also perf_aux_sample_output().
6954 if (READ_ONCE(rb->aux_in_sampling)) {
6957 size = min_t(size_t, size, perf_aux_size(rb));
6958 data->aux_size = ALIGN(size, sizeof(u64));
6960 ring_buffer_put(rb);
6963 return data->aux_size;
6966 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6967 struct perf_event *event,
6968 struct perf_output_handle *handle,
6971 unsigned long flags;
6975 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6976 * paths. If we start calling them in NMI context, they may race with
6977 * the IRQ ones, that is, for example, re-starting an event that's just
6978 * been stopped, which is why we're using a separate callback that
6979 * doesn't change the event state.
6981 * IRQs need to be disabled to prevent IPIs from racing with us.
6983 local_irq_save(flags);
6985 * Guard against NMI hits inside the critical section;
6986 * see also perf_prepare_sample_aux().
6988 WRITE_ONCE(rb->aux_in_sampling, 1);
6991 ret = event->pmu->snapshot_aux(event, handle, size);
6994 WRITE_ONCE(rb->aux_in_sampling, 0);
6995 local_irq_restore(flags);
7000 static void perf_aux_sample_output(struct perf_event *event,
7001 struct perf_output_handle *handle,
7002 struct perf_sample_data *data)
7004 struct perf_event *sampler = event->aux_event;
7005 struct perf_buffer *rb;
7009 if (WARN_ON_ONCE(!sampler || !data->aux_size))
7012 rb = ring_buffer_get(sampler);
7016 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
7019 * An error here means that perf_output_copy() failed (returned a
7020 * non-zero surplus that it didn't copy), which in its current
7021 * enlightened implementation is not possible. If that changes, we'd
7024 if (WARN_ON_ONCE(size < 0))
7028 * The pad comes from ALIGN()ing data->aux_size up to u64 in
7029 * perf_prepare_sample_aux(), so should not be more than that.
7031 pad = data->aux_size - size;
7032 if (WARN_ON_ONCE(pad >= sizeof(u64)))
7037 perf_output_copy(handle, &zero, pad);
7041 ring_buffer_put(rb);
7045 * A set of common sample data types saved even for non-sample records
7046 * when event->attr.sample_id_all is set.
7048 #define PERF_SAMPLE_ID_ALL (PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \
7049 PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID | \
7050 PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER)
7052 static void __perf_event_header__init_id(struct perf_sample_data *data,
7053 struct perf_event *event,
7056 data->type = event->attr.sample_type;
7057 data->sample_flags |= data->type & PERF_SAMPLE_ID_ALL;
7059 if (sample_type & PERF_SAMPLE_TID) {
7060 /* namespace issues */
7061 data->tid_entry.pid = perf_event_pid(event, current);
7062 data->tid_entry.tid = perf_event_tid(event, current);
7065 if (sample_type & PERF_SAMPLE_TIME)
7066 data->time = perf_event_clock(event);
7068 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
7069 data->id = primary_event_id(event);
7071 if (sample_type & PERF_SAMPLE_STREAM_ID)
7072 data->stream_id = event->id;
7074 if (sample_type & PERF_SAMPLE_CPU) {
7075 data->cpu_entry.cpu = raw_smp_processor_id();
7076 data->cpu_entry.reserved = 0;
7080 void perf_event_header__init_id(struct perf_event_header *header,
7081 struct perf_sample_data *data,
7082 struct perf_event *event)
7084 if (event->attr.sample_id_all) {
7085 header->size += event->id_header_size;
7086 __perf_event_header__init_id(data, event, event->attr.sample_type);
7090 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
7091 struct perf_sample_data *data)
7093 u64 sample_type = data->type;
7095 if (sample_type & PERF_SAMPLE_TID)
7096 perf_output_put(handle, data->tid_entry);
7098 if (sample_type & PERF_SAMPLE_TIME)
7099 perf_output_put(handle, data->time);
7101 if (sample_type & PERF_SAMPLE_ID)
7102 perf_output_put(handle, data->id);
7104 if (sample_type & PERF_SAMPLE_STREAM_ID)
7105 perf_output_put(handle, data->stream_id);
7107 if (sample_type & PERF_SAMPLE_CPU)
7108 perf_output_put(handle, data->cpu_entry);
7110 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7111 perf_output_put(handle, data->id);
7114 void perf_event__output_id_sample(struct perf_event *event,
7115 struct perf_output_handle *handle,
7116 struct perf_sample_data *sample)
7118 if (event->attr.sample_id_all)
7119 __perf_event__output_id_sample(handle, sample);
7122 static void perf_output_read_one(struct perf_output_handle *handle,
7123 struct perf_event *event,
7124 u64 enabled, u64 running)
7126 u64 read_format = event->attr.read_format;
7130 values[n++] = perf_event_count(event);
7131 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
7132 values[n++] = enabled +
7133 atomic64_read(&event->child_total_time_enabled);
7135 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
7136 values[n++] = running +
7137 atomic64_read(&event->child_total_time_running);
7139 if (read_format & PERF_FORMAT_ID)
7140 values[n++] = primary_event_id(event);
7141 if (read_format & PERF_FORMAT_LOST)
7142 values[n++] = atomic64_read(&event->lost_samples);
7144 __output_copy(handle, values, n * sizeof(u64));
7147 static void perf_output_read_group(struct perf_output_handle *handle,
7148 struct perf_event *event,
7149 u64 enabled, u64 running)
7151 struct perf_event *leader = event->group_leader, *sub;
7152 u64 read_format = event->attr.read_format;
7153 unsigned long flags;
7158 * Disabling interrupts avoids all counter scheduling
7159 * (context switches, timer based rotation and IPIs).
7161 local_irq_save(flags);
7163 values[n++] = 1 + leader->nr_siblings;
7165 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
7166 values[n++] = enabled;
7168 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
7169 values[n++] = running;
7171 if ((leader != event) &&
7172 (leader->state == PERF_EVENT_STATE_ACTIVE))
7173 leader->pmu->read(leader);
7175 values[n++] = perf_event_count(leader);
7176 if (read_format & PERF_FORMAT_ID)
7177 values[n++] = primary_event_id(leader);
7178 if (read_format & PERF_FORMAT_LOST)
7179 values[n++] = atomic64_read(&leader->lost_samples);
7181 __output_copy(handle, values, n * sizeof(u64));
7183 for_each_sibling_event(sub, leader) {
7186 if ((sub != event) &&
7187 (sub->state == PERF_EVENT_STATE_ACTIVE))
7188 sub->pmu->read(sub);
7190 values[n++] = perf_event_count(sub);
7191 if (read_format & PERF_FORMAT_ID)
7192 values[n++] = primary_event_id(sub);
7193 if (read_format & PERF_FORMAT_LOST)
7194 values[n++] = atomic64_read(&sub->lost_samples);
7196 __output_copy(handle, values, n * sizeof(u64));
7199 local_irq_restore(flags);
7202 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7203 PERF_FORMAT_TOTAL_TIME_RUNNING)
7206 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7208 * The problem is that its both hard and excessively expensive to iterate the
7209 * child list, not to mention that its impossible to IPI the children running
7210 * on another CPU, from interrupt/NMI context.
7212 static void perf_output_read(struct perf_output_handle *handle,
7213 struct perf_event *event)
7215 u64 enabled = 0, running = 0, now;
7216 u64 read_format = event->attr.read_format;
7219 * compute total_time_enabled, total_time_running
7220 * based on snapshot values taken when the event
7221 * was last scheduled in.
7223 * we cannot simply called update_context_time()
7224 * because of locking issue as we are called in
7227 if (read_format & PERF_FORMAT_TOTAL_TIMES)
7228 calc_timer_values(event, &now, &enabled, &running);
7230 if (event->attr.read_format & PERF_FORMAT_GROUP)
7231 perf_output_read_group(handle, event, enabled, running);
7233 perf_output_read_one(handle, event, enabled, running);
7236 void perf_output_sample(struct perf_output_handle *handle,
7237 struct perf_event_header *header,
7238 struct perf_sample_data *data,
7239 struct perf_event *event)
7241 u64 sample_type = data->type;
7243 perf_output_put(handle, *header);
7245 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7246 perf_output_put(handle, data->id);
7248 if (sample_type & PERF_SAMPLE_IP)
7249 perf_output_put(handle, data->ip);
7251 if (sample_type & PERF_SAMPLE_TID)
7252 perf_output_put(handle, data->tid_entry);
7254 if (sample_type & PERF_SAMPLE_TIME)
7255 perf_output_put(handle, data->time);
7257 if (sample_type & PERF_SAMPLE_ADDR)
7258 perf_output_put(handle, data->addr);
7260 if (sample_type & PERF_SAMPLE_ID)
7261 perf_output_put(handle, data->id);
7263 if (sample_type & PERF_SAMPLE_STREAM_ID)
7264 perf_output_put(handle, data->stream_id);
7266 if (sample_type & PERF_SAMPLE_CPU)
7267 perf_output_put(handle, data->cpu_entry);
7269 if (sample_type & PERF_SAMPLE_PERIOD)
7270 perf_output_put(handle, data->period);
7272 if (sample_type & PERF_SAMPLE_READ)
7273 perf_output_read(handle, event);
7275 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7278 size += data->callchain->nr;
7279 size *= sizeof(u64);
7280 __output_copy(handle, data->callchain, size);
7283 if (sample_type & PERF_SAMPLE_RAW) {
7284 struct perf_raw_record *raw = data->raw;
7287 struct perf_raw_frag *frag = &raw->frag;
7289 perf_output_put(handle, raw->size);
7292 __output_custom(handle, frag->copy,
7293 frag->data, frag->size);
7295 __output_copy(handle, frag->data,
7298 if (perf_raw_frag_last(frag))
7303 __output_skip(handle, NULL, frag->pad);
7309 .size = sizeof(u32),
7312 perf_output_put(handle, raw);
7316 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7317 if (data->br_stack) {
7320 size = data->br_stack->nr
7321 * sizeof(struct perf_branch_entry);
7323 perf_output_put(handle, data->br_stack->nr);
7324 if (branch_sample_hw_index(event))
7325 perf_output_put(handle, data->br_stack->hw_idx);
7326 perf_output_copy(handle, data->br_stack->entries, size);
7329 * we always store at least the value of nr
7332 perf_output_put(handle, nr);
7336 if (sample_type & PERF_SAMPLE_REGS_USER) {
7337 u64 abi = data->regs_user.abi;
7340 * If there are no regs to dump, notice it through
7341 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7343 perf_output_put(handle, abi);
7346 u64 mask = event->attr.sample_regs_user;
7347 perf_output_sample_regs(handle,
7348 data->regs_user.regs,
7353 if (sample_type & PERF_SAMPLE_STACK_USER) {
7354 perf_output_sample_ustack(handle,
7355 data->stack_user_size,
7356 data->regs_user.regs);
7359 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7360 perf_output_put(handle, data->weight.full);
7362 if (sample_type & PERF_SAMPLE_DATA_SRC)
7363 perf_output_put(handle, data->data_src.val);
7365 if (sample_type & PERF_SAMPLE_TRANSACTION)
7366 perf_output_put(handle, data->txn);
7368 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7369 u64 abi = data->regs_intr.abi;
7371 * If there are no regs to dump, notice it through
7372 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7374 perf_output_put(handle, abi);
7377 u64 mask = event->attr.sample_regs_intr;
7379 perf_output_sample_regs(handle,
7380 data->regs_intr.regs,
7385 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7386 perf_output_put(handle, data->phys_addr);
7388 if (sample_type & PERF_SAMPLE_CGROUP)
7389 perf_output_put(handle, data->cgroup);
7391 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7392 perf_output_put(handle, data->data_page_size);
7394 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7395 perf_output_put(handle, data->code_page_size);
7397 if (sample_type & PERF_SAMPLE_AUX) {
7398 perf_output_put(handle, data->aux_size);
7401 perf_aux_sample_output(event, handle, data);
7404 if (!event->attr.watermark) {
7405 int wakeup_events = event->attr.wakeup_events;
7407 if (wakeup_events) {
7408 struct perf_buffer *rb = handle->rb;
7409 int events = local_inc_return(&rb->events);
7411 if (events >= wakeup_events) {
7412 local_sub(wakeup_events, &rb->events);
7413 local_inc(&rb->wakeup);
7419 static u64 perf_virt_to_phys(u64 virt)
7426 if (virt >= TASK_SIZE) {
7427 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7428 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7429 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7430 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7433 * Walking the pages tables for user address.
7434 * Interrupts are disabled, so it prevents any tear down
7435 * of the page tables.
7436 * Try IRQ-safe get_user_page_fast_only first.
7437 * If failed, leave phys_addr as 0.
7439 if (current->mm != NULL) {
7442 pagefault_disable();
7443 if (get_user_page_fast_only(virt, 0, &p)) {
7444 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7455 * Return the pagetable size of a given virtual address.
7457 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7461 #ifdef CONFIG_HAVE_FAST_GUP
7468 pgdp = pgd_offset(mm, addr);
7469 pgd = READ_ONCE(*pgdp);
7474 return pgd_leaf_size(pgd);
7476 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7477 p4d = READ_ONCE(*p4dp);
7478 if (!p4d_present(p4d))
7482 return p4d_leaf_size(p4d);
7484 pudp = pud_offset_lockless(p4dp, p4d, addr);
7485 pud = READ_ONCE(*pudp);
7486 if (!pud_present(pud))
7490 return pud_leaf_size(pud);
7492 pmdp = pmd_offset_lockless(pudp, pud, addr);
7494 pmd = pmdp_get_lockless(pmdp);
7495 if (!pmd_present(pmd))
7499 return pmd_leaf_size(pmd);
7501 ptep = pte_offset_map(&pmd, addr);
7505 pte = ptep_get_lockless(ptep);
7506 if (pte_present(pte))
7507 size = pte_leaf_size(pte);
7509 #endif /* CONFIG_HAVE_FAST_GUP */
7514 static u64 perf_get_page_size(unsigned long addr)
7516 struct mm_struct *mm;
7517 unsigned long flags;
7524 * Software page-table walkers must disable IRQs,
7525 * which prevents any tear down of the page tables.
7527 local_irq_save(flags);
7532 * For kernel threads and the like, use init_mm so that
7533 * we can find kernel memory.
7538 size = perf_get_pgtable_size(mm, addr);
7540 local_irq_restore(flags);
7545 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7547 struct perf_callchain_entry *
7548 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7550 bool kernel = !event->attr.exclude_callchain_kernel;
7551 bool user = !event->attr.exclude_callchain_user;
7552 /* Disallow cross-task user callchains. */
7553 bool crosstask = event->ctx->task && event->ctx->task != current;
7554 const u32 max_stack = event->attr.sample_max_stack;
7555 struct perf_callchain_entry *callchain;
7557 if (!kernel && !user)
7558 return &__empty_callchain;
7560 callchain = get_perf_callchain(regs, 0, kernel, user,
7561 max_stack, crosstask, true);
7562 return callchain ?: &__empty_callchain;
7565 static __always_inline u64 __cond_set(u64 flags, u64 s, u64 d)
7567 return d * !!(flags & s);
7570 void perf_prepare_sample(struct perf_sample_data *data,
7571 struct perf_event *event,
7572 struct pt_regs *regs)
7574 u64 sample_type = event->attr.sample_type;
7575 u64 filtered_sample_type;
7578 * Add the sample flags that are dependent to others. And clear the
7579 * sample flags that have already been done by the PMU driver.
7581 filtered_sample_type = sample_type;
7582 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_CODE_PAGE_SIZE,
7584 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_DATA_PAGE_SIZE |
7585 PERF_SAMPLE_PHYS_ADDR, PERF_SAMPLE_ADDR);
7586 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_STACK_USER,
7587 PERF_SAMPLE_REGS_USER);
7588 filtered_sample_type &= ~data->sample_flags;
7590 if (filtered_sample_type == 0) {
7591 /* Make sure it has the correct data->type for output */
7592 data->type = event->attr.sample_type;
7596 __perf_event_header__init_id(data, event, filtered_sample_type);
7598 if (filtered_sample_type & PERF_SAMPLE_IP) {
7599 data->ip = perf_instruction_pointer(regs);
7600 data->sample_flags |= PERF_SAMPLE_IP;
7603 if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
7604 perf_sample_save_callchain(data, event, regs);
7606 if (filtered_sample_type & PERF_SAMPLE_RAW) {
7608 data->dyn_size += sizeof(u64);
7609 data->sample_flags |= PERF_SAMPLE_RAW;
7612 if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) {
7613 data->br_stack = NULL;
7614 data->dyn_size += sizeof(u64);
7615 data->sample_flags |= PERF_SAMPLE_BRANCH_STACK;
7618 if (filtered_sample_type & PERF_SAMPLE_REGS_USER)
7619 perf_sample_regs_user(&data->regs_user, regs);
7622 * It cannot use the filtered_sample_type here as REGS_USER can be set
7623 * by STACK_USER (using __cond_set() above) and we don't want to update
7624 * the dyn_size if it's not requested by users.
7626 if ((sample_type & ~data->sample_flags) & PERF_SAMPLE_REGS_USER) {
7627 /* regs dump ABI info */
7628 int size = sizeof(u64);
7630 if (data->regs_user.regs) {
7631 u64 mask = event->attr.sample_regs_user;
7632 size += hweight64(mask) * sizeof(u64);
7635 data->dyn_size += size;
7636 data->sample_flags |= PERF_SAMPLE_REGS_USER;
7639 if (filtered_sample_type & PERF_SAMPLE_STACK_USER) {
7641 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7642 * processed as the last one or have additional check added
7643 * in case new sample type is added, because we could eat
7644 * up the rest of the sample size.
7646 u16 stack_size = event->attr.sample_stack_user;
7647 u16 header_size = perf_sample_data_size(data, event);
7648 u16 size = sizeof(u64);
7650 stack_size = perf_sample_ustack_size(stack_size, header_size,
7651 data->regs_user.regs);
7654 * If there is something to dump, add space for the dump
7655 * itself and for the field that tells the dynamic size,
7656 * which is how many have been actually dumped.
7659 size += sizeof(u64) + stack_size;
7661 data->stack_user_size = stack_size;
7662 data->dyn_size += size;
7663 data->sample_flags |= PERF_SAMPLE_STACK_USER;
7666 if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) {
7667 data->weight.full = 0;
7668 data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE;
7671 if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) {
7672 data->data_src.val = PERF_MEM_NA;
7673 data->sample_flags |= PERF_SAMPLE_DATA_SRC;
7676 if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) {
7678 data->sample_flags |= PERF_SAMPLE_TRANSACTION;
7681 if (filtered_sample_type & PERF_SAMPLE_ADDR) {
7683 data->sample_flags |= PERF_SAMPLE_ADDR;
7686 if (filtered_sample_type & PERF_SAMPLE_REGS_INTR) {
7687 /* regs dump ABI info */
7688 int size = sizeof(u64);
7690 perf_sample_regs_intr(&data->regs_intr, regs);
7692 if (data->regs_intr.regs) {
7693 u64 mask = event->attr.sample_regs_intr;
7695 size += hweight64(mask) * sizeof(u64);
7698 data->dyn_size += size;
7699 data->sample_flags |= PERF_SAMPLE_REGS_INTR;
7702 if (filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) {
7703 data->phys_addr = perf_virt_to_phys(data->addr);
7704 data->sample_flags |= PERF_SAMPLE_PHYS_ADDR;
7707 #ifdef CONFIG_CGROUP_PERF
7708 if (filtered_sample_type & PERF_SAMPLE_CGROUP) {
7709 struct cgroup *cgrp;
7711 /* protected by RCU */
7712 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7713 data->cgroup = cgroup_id(cgrp);
7714 data->sample_flags |= PERF_SAMPLE_CGROUP;
7719 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7720 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7721 * but the value will not dump to the userspace.
7723 if (filtered_sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) {
7724 data->data_page_size = perf_get_page_size(data->addr);
7725 data->sample_flags |= PERF_SAMPLE_DATA_PAGE_SIZE;
7728 if (filtered_sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) {
7729 data->code_page_size = perf_get_page_size(data->ip);
7730 data->sample_flags |= PERF_SAMPLE_CODE_PAGE_SIZE;
7733 if (filtered_sample_type & PERF_SAMPLE_AUX) {
7735 u16 header_size = perf_sample_data_size(data, event);
7737 header_size += sizeof(u64); /* size */
7740 * Given the 16bit nature of header::size, an AUX sample can
7741 * easily overflow it, what with all the preceding sample bits.
7742 * Make sure this doesn't happen by using up to U16_MAX bytes
7743 * per sample in total (rounded down to 8 byte boundary).
7745 size = min_t(size_t, U16_MAX - header_size,
7746 event->attr.aux_sample_size);
7747 size = rounddown(size, 8);
7748 size = perf_prepare_sample_aux(event, data, size);
7750 WARN_ON_ONCE(size + header_size > U16_MAX);
7751 data->dyn_size += size + sizeof(u64); /* size above */
7752 data->sample_flags |= PERF_SAMPLE_AUX;
7756 void perf_prepare_header(struct perf_event_header *header,
7757 struct perf_sample_data *data,
7758 struct perf_event *event,
7759 struct pt_regs *regs)
7761 header->type = PERF_RECORD_SAMPLE;
7762 header->size = perf_sample_data_size(data, event);
7763 header->misc = perf_misc_flags(regs);
7766 * If you're adding more sample types here, you likely need to do
7767 * something about the overflowing header::size, like repurpose the
7768 * lowest 3 bits of size, which should be always zero at the moment.
7769 * This raises a more important question, do we really need 512k sized
7770 * samples and why, so good argumentation is in order for whatever you
7773 WARN_ON_ONCE(header->size & 7);
7776 static __always_inline int
7777 __perf_event_output(struct perf_event *event,
7778 struct perf_sample_data *data,
7779 struct pt_regs *regs,
7780 int (*output_begin)(struct perf_output_handle *,
7781 struct perf_sample_data *,
7782 struct perf_event *,
7785 struct perf_output_handle handle;
7786 struct perf_event_header header;
7789 /* protect the callchain buffers */
7792 perf_prepare_sample(data, event, regs);
7793 perf_prepare_header(&header, data, event, regs);
7795 err = output_begin(&handle, data, event, header.size);
7799 perf_output_sample(&handle, &header, data, event);
7801 perf_output_end(&handle);
7809 perf_event_output_forward(struct perf_event *event,
7810 struct perf_sample_data *data,
7811 struct pt_regs *regs)
7813 __perf_event_output(event, data, regs, perf_output_begin_forward);
7817 perf_event_output_backward(struct perf_event *event,
7818 struct perf_sample_data *data,
7819 struct pt_regs *regs)
7821 __perf_event_output(event, data, regs, perf_output_begin_backward);
7825 perf_event_output(struct perf_event *event,
7826 struct perf_sample_data *data,
7827 struct pt_regs *regs)
7829 return __perf_event_output(event, data, regs, perf_output_begin);
7836 struct perf_read_event {
7837 struct perf_event_header header;
7844 perf_event_read_event(struct perf_event *event,
7845 struct task_struct *task)
7847 struct perf_output_handle handle;
7848 struct perf_sample_data sample;
7849 struct perf_read_event read_event = {
7851 .type = PERF_RECORD_READ,
7853 .size = sizeof(read_event) + event->read_size,
7855 .pid = perf_event_pid(event, task),
7856 .tid = perf_event_tid(event, task),
7860 perf_event_header__init_id(&read_event.header, &sample, event);
7861 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7865 perf_output_put(&handle, read_event);
7866 perf_output_read(&handle, event);
7867 perf_event__output_id_sample(event, &handle, &sample);
7869 perf_output_end(&handle);
7872 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7875 perf_iterate_ctx(struct perf_event_context *ctx,
7876 perf_iterate_f output,
7877 void *data, bool all)
7879 struct perf_event *event;
7881 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7883 if (event->state < PERF_EVENT_STATE_INACTIVE)
7885 if (!event_filter_match(event))
7889 output(event, data);
7893 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7895 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7896 struct perf_event *event;
7898 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7900 * Skip events that are not fully formed yet; ensure that
7901 * if we observe event->ctx, both event and ctx will be
7902 * complete enough. See perf_install_in_context().
7904 if (!smp_load_acquire(&event->ctx))
7907 if (event->state < PERF_EVENT_STATE_INACTIVE)
7909 if (!event_filter_match(event))
7911 output(event, data);
7916 * Iterate all events that need to receive side-band events.
7918 * For new callers; ensure that account_pmu_sb_event() includes
7919 * your event, otherwise it might not get delivered.
7922 perf_iterate_sb(perf_iterate_f output, void *data,
7923 struct perf_event_context *task_ctx)
7925 struct perf_event_context *ctx;
7931 * If we have task_ctx != NULL we only notify the task context itself.
7932 * The task_ctx is set only for EXIT events before releasing task
7936 perf_iterate_ctx(task_ctx, output, data, false);
7940 perf_iterate_sb_cpu(output, data);
7942 ctx = rcu_dereference(current->perf_event_ctxp);
7944 perf_iterate_ctx(ctx, output, data, false);
7951 * Clear all file-based filters at exec, they'll have to be
7952 * re-instated when/if these objects are mmapped again.
7954 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7956 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7957 struct perf_addr_filter *filter;
7958 unsigned int restart = 0, count = 0;
7959 unsigned long flags;
7961 if (!has_addr_filter(event))
7964 raw_spin_lock_irqsave(&ifh->lock, flags);
7965 list_for_each_entry(filter, &ifh->list, entry) {
7966 if (filter->path.dentry) {
7967 event->addr_filter_ranges[count].start = 0;
7968 event->addr_filter_ranges[count].size = 0;
7976 event->addr_filters_gen++;
7977 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7980 perf_event_stop(event, 1);
7983 void perf_event_exec(void)
7985 struct perf_event_context *ctx;
7987 ctx = perf_pin_task_context(current);
7991 perf_event_enable_on_exec(ctx);
7992 perf_event_remove_on_exec(ctx);
7993 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
7995 perf_unpin_context(ctx);
7999 struct remote_output {
8000 struct perf_buffer *rb;
8004 static void __perf_event_output_stop(struct perf_event *event, void *data)
8006 struct perf_event *parent = event->parent;
8007 struct remote_output *ro = data;
8008 struct perf_buffer *rb = ro->rb;
8009 struct stop_event_data sd = {
8013 if (!has_aux(event))
8020 * In case of inheritance, it will be the parent that links to the
8021 * ring-buffer, but it will be the child that's actually using it.
8023 * We are using event::rb to determine if the event should be stopped,
8024 * however this may race with ring_buffer_attach() (through set_output),
8025 * which will make us skip the event that actually needs to be stopped.
8026 * So ring_buffer_attach() has to stop an aux event before re-assigning
8029 if (rcu_dereference(parent->rb) == rb)
8030 ro->err = __perf_event_stop(&sd);
8033 static int __perf_pmu_output_stop(void *info)
8035 struct perf_event *event = info;
8036 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
8037 struct remote_output ro = {
8042 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
8043 if (cpuctx->task_ctx)
8044 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
8051 static void perf_pmu_output_stop(struct perf_event *event)
8053 struct perf_event *iter;
8058 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
8060 * For per-CPU events, we need to make sure that neither they
8061 * nor their children are running; for cpu==-1 events it's
8062 * sufficient to stop the event itself if it's active, since
8063 * it can't have children.
8067 cpu = READ_ONCE(iter->oncpu);
8072 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
8073 if (err == -EAGAIN) {
8082 * task tracking -- fork/exit
8084 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
8087 struct perf_task_event {
8088 struct task_struct *task;
8089 struct perf_event_context *task_ctx;
8092 struct perf_event_header header;
8102 static int perf_event_task_match(struct perf_event *event)
8104 return event->attr.comm || event->attr.mmap ||
8105 event->attr.mmap2 || event->attr.mmap_data ||
8109 static void perf_event_task_output(struct perf_event *event,
8112 struct perf_task_event *task_event = data;
8113 struct perf_output_handle handle;
8114 struct perf_sample_data sample;
8115 struct task_struct *task = task_event->task;
8116 int ret, size = task_event->event_id.header.size;
8118 if (!perf_event_task_match(event))
8121 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
8123 ret = perf_output_begin(&handle, &sample, event,
8124 task_event->event_id.header.size);
8128 task_event->event_id.pid = perf_event_pid(event, task);
8129 task_event->event_id.tid = perf_event_tid(event, task);
8131 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
8132 task_event->event_id.ppid = perf_event_pid(event,
8134 task_event->event_id.ptid = perf_event_pid(event,
8136 } else { /* PERF_RECORD_FORK */
8137 task_event->event_id.ppid = perf_event_pid(event, current);
8138 task_event->event_id.ptid = perf_event_tid(event, current);
8141 task_event->event_id.time = perf_event_clock(event);
8143 perf_output_put(&handle, task_event->event_id);
8145 perf_event__output_id_sample(event, &handle, &sample);
8147 perf_output_end(&handle);
8149 task_event->event_id.header.size = size;
8152 static void perf_event_task(struct task_struct *task,
8153 struct perf_event_context *task_ctx,
8156 struct perf_task_event task_event;
8158 if (!atomic_read(&nr_comm_events) &&
8159 !atomic_read(&nr_mmap_events) &&
8160 !atomic_read(&nr_task_events))
8163 task_event = (struct perf_task_event){
8165 .task_ctx = task_ctx,
8168 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
8170 .size = sizeof(task_event.event_id),
8180 perf_iterate_sb(perf_event_task_output,
8185 void perf_event_fork(struct task_struct *task)
8187 perf_event_task(task, NULL, 1);
8188 perf_event_namespaces(task);
8195 struct perf_comm_event {
8196 struct task_struct *task;
8201 struct perf_event_header header;
8208 static int perf_event_comm_match(struct perf_event *event)
8210 return event->attr.comm;
8213 static void perf_event_comm_output(struct perf_event *event,
8216 struct perf_comm_event *comm_event = data;
8217 struct perf_output_handle handle;
8218 struct perf_sample_data sample;
8219 int size = comm_event->event_id.header.size;
8222 if (!perf_event_comm_match(event))
8225 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
8226 ret = perf_output_begin(&handle, &sample, event,
8227 comm_event->event_id.header.size);
8232 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8233 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8235 perf_output_put(&handle, comm_event->event_id);
8236 __output_copy(&handle, comm_event->comm,
8237 comm_event->comm_size);
8239 perf_event__output_id_sample(event, &handle, &sample);
8241 perf_output_end(&handle);
8243 comm_event->event_id.header.size = size;
8246 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8248 char comm[TASK_COMM_LEN];
8251 memset(comm, 0, sizeof(comm));
8252 strscpy(comm, comm_event->task->comm, sizeof(comm));
8253 size = ALIGN(strlen(comm)+1, sizeof(u64));
8255 comm_event->comm = comm;
8256 comm_event->comm_size = size;
8258 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8260 perf_iterate_sb(perf_event_comm_output,
8265 void perf_event_comm(struct task_struct *task, bool exec)
8267 struct perf_comm_event comm_event;
8269 if (!atomic_read(&nr_comm_events))
8272 comm_event = (struct perf_comm_event){
8278 .type = PERF_RECORD_COMM,
8279 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8287 perf_event_comm_event(&comm_event);
8291 * namespaces tracking
8294 struct perf_namespaces_event {
8295 struct task_struct *task;
8298 struct perf_event_header header;
8303 struct perf_ns_link_info link_info[NR_NAMESPACES];
8307 static int perf_event_namespaces_match(struct perf_event *event)
8309 return event->attr.namespaces;
8312 static void perf_event_namespaces_output(struct perf_event *event,
8315 struct perf_namespaces_event *namespaces_event = data;
8316 struct perf_output_handle handle;
8317 struct perf_sample_data sample;
8318 u16 header_size = namespaces_event->event_id.header.size;
8321 if (!perf_event_namespaces_match(event))
8324 perf_event_header__init_id(&namespaces_event->event_id.header,
8326 ret = perf_output_begin(&handle, &sample, event,
8327 namespaces_event->event_id.header.size);
8331 namespaces_event->event_id.pid = perf_event_pid(event,
8332 namespaces_event->task);
8333 namespaces_event->event_id.tid = perf_event_tid(event,
8334 namespaces_event->task);
8336 perf_output_put(&handle, namespaces_event->event_id);
8338 perf_event__output_id_sample(event, &handle, &sample);
8340 perf_output_end(&handle);
8342 namespaces_event->event_id.header.size = header_size;
8345 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8346 struct task_struct *task,
8347 const struct proc_ns_operations *ns_ops)
8349 struct path ns_path;
8350 struct inode *ns_inode;
8353 error = ns_get_path(&ns_path, task, ns_ops);
8355 ns_inode = ns_path.dentry->d_inode;
8356 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8357 ns_link_info->ino = ns_inode->i_ino;
8362 void perf_event_namespaces(struct task_struct *task)
8364 struct perf_namespaces_event namespaces_event;
8365 struct perf_ns_link_info *ns_link_info;
8367 if (!atomic_read(&nr_namespaces_events))
8370 namespaces_event = (struct perf_namespaces_event){
8374 .type = PERF_RECORD_NAMESPACES,
8376 .size = sizeof(namespaces_event.event_id),
8380 .nr_namespaces = NR_NAMESPACES,
8381 /* .link_info[NR_NAMESPACES] */
8385 ns_link_info = namespaces_event.event_id.link_info;
8387 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8388 task, &mntns_operations);
8390 #ifdef CONFIG_USER_NS
8391 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8392 task, &userns_operations);
8394 #ifdef CONFIG_NET_NS
8395 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8396 task, &netns_operations);
8398 #ifdef CONFIG_UTS_NS
8399 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8400 task, &utsns_operations);
8402 #ifdef CONFIG_IPC_NS
8403 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8404 task, &ipcns_operations);
8406 #ifdef CONFIG_PID_NS
8407 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8408 task, &pidns_operations);
8410 #ifdef CONFIG_CGROUPS
8411 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8412 task, &cgroupns_operations);
8415 perf_iterate_sb(perf_event_namespaces_output,
8423 #ifdef CONFIG_CGROUP_PERF
8425 struct perf_cgroup_event {
8429 struct perf_event_header header;
8435 static int perf_event_cgroup_match(struct perf_event *event)
8437 return event->attr.cgroup;
8440 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8442 struct perf_cgroup_event *cgroup_event = data;
8443 struct perf_output_handle handle;
8444 struct perf_sample_data sample;
8445 u16 header_size = cgroup_event->event_id.header.size;
8448 if (!perf_event_cgroup_match(event))
8451 perf_event_header__init_id(&cgroup_event->event_id.header,
8453 ret = perf_output_begin(&handle, &sample, event,
8454 cgroup_event->event_id.header.size);
8458 perf_output_put(&handle, cgroup_event->event_id);
8459 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8461 perf_event__output_id_sample(event, &handle, &sample);
8463 perf_output_end(&handle);
8465 cgroup_event->event_id.header.size = header_size;
8468 static void perf_event_cgroup(struct cgroup *cgrp)
8470 struct perf_cgroup_event cgroup_event;
8471 char path_enomem[16] = "//enomem";
8475 if (!atomic_read(&nr_cgroup_events))
8478 cgroup_event = (struct perf_cgroup_event){
8481 .type = PERF_RECORD_CGROUP,
8483 .size = sizeof(cgroup_event.event_id),
8485 .id = cgroup_id(cgrp),
8489 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8490 if (pathname == NULL) {
8491 cgroup_event.path = path_enomem;
8493 /* just to be sure to have enough space for alignment */
8494 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8495 cgroup_event.path = pathname;
8499 * Since our buffer works in 8 byte units we need to align our string
8500 * size to a multiple of 8. However, we must guarantee the tail end is
8501 * zero'd out to avoid leaking random bits to userspace.
8503 size = strlen(cgroup_event.path) + 1;
8504 while (!IS_ALIGNED(size, sizeof(u64)))
8505 cgroup_event.path[size++] = '\0';
8507 cgroup_event.event_id.header.size += size;
8508 cgroup_event.path_size = size;
8510 perf_iterate_sb(perf_event_cgroup_output,
8523 struct perf_mmap_event {
8524 struct vm_area_struct *vma;
8526 const char *file_name;
8532 u8 build_id[BUILD_ID_SIZE_MAX];
8536 struct perf_event_header header;
8546 static int perf_event_mmap_match(struct perf_event *event,
8549 struct perf_mmap_event *mmap_event = data;
8550 struct vm_area_struct *vma = mmap_event->vma;
8551 int executable = vma->vm_flags & VM_EXEC;
8553 return (!executable && event->attr.mmap_data) ||
8554 (executable && (event->attr.mmap || event->attr.mmap2));
8557 static void perf_event_mmap_output(struct perf_event *event,
8560 struct perf_mmap_event *mmap_event = data;
8561 struct perf_output_handle handle;
8562 struct perf_sample_data sample;
8563 int size = mmap_event->event_id.header.size;
8564 u32 type = mmap_event->event_id.header.type;
8568 if (!perf_event_mmap_match(event, data))
8571 if (event->attr.mmap2) {
8572 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8573 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8574 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8575 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8576 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8577 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8578 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8581 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8582 ret = perf_output_begin(&handle, &sample, event,
8583 mmap_event->event_id.header.size);
8587 mmap_event->event_id.pid = perf_event_pid(event, current);
8588 mmap_event->event_id.tid = perf_event_tid(event, current);
8590 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8592 if (event->attr.mmap2 && use_build_id)
8593 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8595 perf_output_put(&handle, mmap_event->event_id);
8597 if (event->attr.mmap2) {
8599 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8601 __output_copy(&handle, size, 4);
8602 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8604 perf_output_put(&handle, mmap_event->maj);
8605 perf_output_put(&handle, mmap_event->min);
8606 perf_output_put(&handle, mmap_event->ino);
8607 perf_output_put(&handle, mmap_event->ino_generation);
8609 perf_output_put(&handle, mmap_event->prot);
8610 perf_output_put(&handle, mmap_event->flags);
8613 __output_copy(&handle, mmap_event->file_name,
8614 mmap_event->file_size);
8616 perf_event__output_id_sample(event, &handle, &sample);
8618 perf_output_end(&handle);
8620 mmap_event->event_id.header.size = size;
8621 mmap_event->event_id.header.type = type;
8624 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8626 struct vm_area_struct *vma = mmap_event->vma;
8627 struct file *file = vma->vm_file;
8628 int maj = 0, min = 0;
8629 u64 ino = 0, gen = 0;
8630 u32 prot = 0, flags = 0;
8636 if (vma->vm_flags & VM_READ)
8638 if (vma->vm_flags & VM_WRITE)
8640 if (vma->vm_flags & VM_EXEC)
8643 if (vma->vm_flags & VM_MAYSHARE)
8646 flags = MAP_PRIVATE;
8648 if (vma->vm_flags & VM_LOCKED)
8649 flags |= MAP_LOCKED;
8650 if (is_vm_hugetlb_page(vma))
8651 flags |= MAP_HUGETLB;
8654 struct inode *inode;
8657 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8663 * d_path() works from the end of the rb backwards, so we
8664 * need to add enough zero bytes after the string to handle
8665 * the 64bit alignment we do later.
8667 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8672 inode = file_inode(vma->vm_file);
8673 dev = inode->i_sb->s_dev;
8675 gen = inode->i_generation;
8681 if (vma->vm_ops && vma->vm_ops->name)
8682 name = (char *) vma->vm_ops->name(vma);
8684 name = (char *)arch_vma_name(vma);
8686 if (vma_is_initial_heap(vma))
8688 else if (vma_is_initial_stack(vma))
8696 strscpy(tmp, name, sizeof(tmp));
8700 * Since our buffer works in 8 byte units we need to align our string
8701 * size to a multiple of 8. However, we must guarantee the tail end is
8702 * zero'd out to avoid leaking random bits to userspace.
8704 size = strlen(name)+1;
8705 while (!IS_ALIGNED(size, sizeof(u64)))
8706 name[size++] = '\0';
8708 mmap_event->file_name = name;
8709 mmap_event->file_size = size;
8710 mmap_event->maj = maj;
8711 mmap_event->min = min;
8712 mmap_event->ino = ino;
8713 mmap_event->ino_generation = gen;
8714 mmap_event->prot = prot;
8715 mmap_event->flags = flags;
8717 if (!(vma->vm_flags & VM_EXEC))
8718 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8720 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8722 if (atomic_read(&nr_build_id_events))
8723 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8725 perf_iterate_sb(perf_event_mmap_output,
8733 * Check whether inode and address range match filter criteria.
8735 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8736 struct file *file, unsigned long offset,
8739 /* d_inode(NULL) won't be equal to any mapped user-space file */
8740 if (!filter->path.dentry)
8743 if (d_inode(filter->path.dentry) != file_inode(file))
8746 if (filter->offset > offset + size)
8749 if (filter->offset + filter->size < offset)
8755 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8756 struct vm_area_struct *vma,
8757 struct perf_addr_filter_range *fr)
8759 unsigned long vma_size = vma->vm_end - vma->vm_start;
8760 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8761 struct file *file = vma->vm_file;
8763 if (!perf_addr_filter_match(filter, file, off, vma_size))
8766 if (filter->offset < off) {
8767 fr->start = vma->vm_start;
8768 fr->size = min(vma_size, filter->size - (off - filter->offset));
8770 fr->start = vma->vm_start + filter->offset - off;
8771 fr->size = min(vma->vm_end - fr->start, filter->size);
8777 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8779 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8780 struct vm_area_struct *vma = data;
8781 struct perf_addr_filter *filter;
8782 unsigned int restart = 0, count = 0;
8783 unsigned long flags;
8785 if (!has_addr_filter(event))
8791 raw_spin_lock_irqsave(&ifh->lock, flags);
8792 list_for_each_entry(filter, &ifh->list, entry) {
8793 if (perf_addr_filter_vma_adjust(filter, vma,
8794 &event->addr_filter_ranges[count]))
8801 event->addr_filters_gen++;
8802 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8805 perf_event_stop(event, 1);
8809 * Adjust all task's events' filters to the new vma
8811 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8813 struct perf_event_context *ctx;
8816 * Data tracing isn't supported yet and as such there is no need
8817 * to keep track of anything that isn't related to executable code:
8819 if (!(vma->vm_flags & VM_EXEC))
8823 ctx = rcu_dereference(current->perf_event_ctxp);
8825 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8829 void perf_event_mmap(struct vm_area_struct *vma)
8831 struct perf_mmap_event mmap_event;
8833 if (!atomic_read(&nr_mmap_events))
8836 mmap_event = (struct perf_mmap_event){
8842 .type = PERF_RECORD_MMAP,
8843 .misc = PERF_RECORD_MISC_USER,
8848 .start = vma->vm_start,
8849 .len = vma->vm_end - vma->vm_start,
8850 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8852 /* .maj (attr_mmap2 only) */
8853 /* .min (attr_mmap2 only) */
8854 /* .ino (attr_mmap2 only) */
8855 /* .ino_generation (attr_mmap2 only) */
8856 /* .prot (attr_mmap2 only) */
8857 /* .flags (attr_mmap2 only) */
8860 perf_addr_filters_adjust(vma);
8861 perf_event_mmap_event(&mmap_event);
8864 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8865 unsigned long size, u64 flags)
8867 struct perf_output_handle handle;
8868 struct perf_sample_data sample;
8869 struct perf_aux_event {
8870 struct perf_event_header header;
8876 .type = PERF_RECORD_AUX,
8878 .size = sizeof(rec),
8886 perf_event_header__init_id(&rec.header, &sample, event);
8887 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8892 perf_output_put(&handle, rec);
8893 perf_event__output_id_sample(event, &handle, &sample);
8895 perf_output_end(&handle);
8899 * Lost/dropped samples logging
8901 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8903 struct perf_output_handle handle;
8904 struct perf_sample_data sample;
8908 struct perf_event_header header;
8910 } lost_samples_event = {
8912 .type = PERF_RECORD_LOST_SAMPLES,
8914 .size = sizeof(lost_samples_event),
8919 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8921 ret = perf_output_begin(&handle, &sample, event,
8922 lost_samples_event.header.size);
8926 perf_output_put(&handle, lost_samples_event);
8927 perf_event__output_id_sample(event, &handle, &sample);
8928 perf_output_end(&handle);
8932 * context_switch tracking
8935 struct perf_switch_event {
8936 struct task_struct *task;
8937 struct task_struct *next_prev;
8940 struct perf_event_header header;
8946 static int perf_event_switch_match(struct perf_event *event)
8948 return event->attr.context_switch;
8951 static void perf_event_switch_output(struct perf_event *event, void *data)
8953 struct perf_switch_event *se = data;
8954 struct perf_output_handle handle;
8955 struct perf_sample_data sample;
8958 if (!perf_event_switch_match(event))
8961 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8962 if (event->ctx->task) {
8963 se->event_id.header.type = PERF_RECORD_SWITCH;
8964 se->event_id.header.size = sizeof(se->event_id.header);
8966 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8967 se->event_id.header.size = sizeof(se->event_id);
8968 se->event_id.next_prev_pid =
8969 perf_event_pid(event, se->next_prev);
8970 se->event_id.next_prev_tid =
8971 perf_event_tid(event, se->next_prev);
8974 perf_event_header__init_id(&se->event_id.header, &sample, event);
8976 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8980 if (event->ctx->task)
8981 perf_output_put(&handle, se->event_id.header);
8983 perf_output_put(&handle, se->event_id);
8985 perf_event__output_id_sample(event, &handle, &sample);
8987 perf_output_end(&handle);
8990 static void perf_event_switch(struct task_struct *task,
8991 struct task_struct *next_prev, bool sched_in)
8993 struct perf_switch_event switch_event;
8995 /* N.B. caller checks nr_switch_events != 0 */
8997 switch_event = (struct perf_switch_event){
8999 .next_prev = next_prev,
9003 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
9006 /* .next_prev_pid */
9007 /* .next_prev_tid */
9011 if (!sched_in && task->on_rq) {
9012 switch_event.event_id.header.misc |=
9013 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
9016 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
9020 * IRQ throttle logging
9023 static void perf_log_throttle(struct perf_event *event, int enable)
9025 struct perf_output_handle handle;
9026 struct perf_sample_data sample;
9030 struct perf_event_header header;
9034 } throttle_event = {
9036 .type = PERF_RECORD_THROTTLE,
9038 .size = sizeof(throttle_event),
9040 .time = perf_event_clock(event),
9041 .id = primary_event_id(event),
9042 .stream_id = event->id,
9046 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
9048 perf_event_header__init_id(&throttle_event.header, &sample, event);
9050 ret = perf_output_begin(&handle, &sample, event,
9051 throttle_event.header.size);
9055 perf_output_put(&handle, throttle_event);
9056 perf_event__output_id_sample(event, &handle, &sample);
9057 perf_output_end(&handle);
9061 * ksymbol register/unregister tracking
9064 struct perf_ksymbol_event {
9068 struct perf_event_header header;
9076 static int perf_event_ksymbol_match(struct perf_event *event)
9078 return event->attr.ksymbol;
9081 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
9083 struct perf_ksymbol_event *ksymbol_event = data;
9084 struct perf_output_handle handle;
9085 struct perf_sample_data sample;
9088 if (!perf_event_ksymbol_match(event))
9091 perf_event_header__init_id(&ksymbol_event->event_id.header,
9093 ret = perf_output_begin(&handle, &sample, event,
9094 ksymbol_event->event_id.header.size);
9098 perf_output_put(&handle, ksymbol_event->event_id);
9099 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
9100 perf_event__output_id_sample(event, &handle, &sample);
9102 perf_output_end(&handle);
9105 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
9108 struct perf_ksymbol_event ksymbol_event;
9109 char name[KSYM_NAME_LEN];
9113 if (!atomic_read(&nr_ksymbol_events))
9116 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
9117 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
9120 strscpy(name, sym, KSYM_NAME_LEN);
9121 name_len = strlen(name) + 1;
9122 while (!IS_ALIGNED(name_len, sizeof(u64)))
9123 name[name_len++] = '\0';
9124 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
9127 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
9129 ksymbol_event = (struct perf_ksymbol_event){
9131 .name_len = name_len,
9134 .type = PERF_RECORD_KSYMBOL,
9135 .size = sizeof(ksymbol_event.event_id) +
9140 .ksym_type = ksym_type,
9145 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
9148 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
9152 * bpf program load/unload tracking
9155 struct perf_bpf_event {
9156 struct bpf_prog *prog;
9158 struct perf_event_header header;
9162 u8 tag[BPF_TAG_SIZE];
9166 static int perf_event_bpf_match(struct perf_event *event)
9168 return event->attr.bpf_event;
9171 static void perf_event_bpf_output(struct perf_event *event, void *data)
9173 struct perf_bpf_event *bpf_event = data;
9174 struct perf_output_handle handle;
9175 struct perf_sample_data sample;
9178 if (!perf_event_bpf_match(event))
9181 perf_event_header__init_id(&bpf_event->event_id.header,
9183 ret = perf_output_begin(&handle, &sample, event,
9184 bpf_event->event_id.header.size);
9188 perf_output_put(&handle, bpf_event->event_id);
9189 perf_event__output_id_sample(event, &handle, &sample);
9191 perf_output_end(&handle);
9194 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
9195 enum perf_bpf_event_type type)
9197 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
9200 if (prog->aux->func_cnt == 0) {
9201 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
9202 (u64)(unsigned long)prog->bpf_func,
9203 prog->jited_len, unregister,
9204 prog->aux->ksym.name);
9206 for (i = 0; i < prog->aux->func_cnt; i++) {
9207 struct bpf_prog *subprog = prog->aux->func[i];
9210 PERF_RECORD_KSYMBOL_TYPE_BPF,
9211 (u64)(unsigned long)subprog->bpf_func,
9212 subprog->jited_len, unregister,
9213 subprog->aux->ksym.name);
9218 void perf_event_bpf_event(struct bpf_prog *prog,
9219 enum perf_bpf_event_type type,
9222 struct perf_bpf_event bpf_event;
9224 if (type <= PERF_BPF_EVENT_UNKNOWN ||
9225 type >= PERF_BPF_EVENT_MAX)
9229 case PERF_BPF_EVENT_PROG_LOAD:
9230 case PERF_BPF_EVENT_PROG_UNLOAD:
9231 if (atomic_read(&nr_ksymbol_events))
9232 perf_event_bpf_emit_ksymbols(prog, type);
9238 if (!atomic_read(&nr_bpf_events))
9241 bpf_event = (struct perf_bpf_event){
9245 .type = PERF_RECORD_BPF_EVENT,
9246 .size = sizeof(bpf_event.event_id),
9250 .id = prog->aux->id,
9254 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9256 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9257 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9260 struct perf_text_poke_event {
9261 const void *old_bytes;
9262 const void *new_bytes;
9268 struct perf_event_header header;
9274 static int perf_event_text_poke_match(struct perf_event *event)
9276 return event->attr.text_poke;
9279 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9281 struct perf_text_poke_event *text_poke_event = data;
9282 struct perf_output_handle handle;
9283 struct perf_sample_data sample;
9287 if (!perf_event_text_poke_match(event))
9290 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9292 ret = perf_output_begin(&handle, &sample, event,
9293 text_poke_event->event_id.header.size);
9297 perf_output_put(&handle, text_poke_event->event_id);
9298 perf_output_put(&handle, text_poke_event->old_len);
9299 perf_output_put(&handle, text_poke_event->new_len);
9301 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9302 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9304 if (text_poke_event->pad)
9305 __output_copy(&handle, &padding, text_poke_event->pad);
9307 perf_event__output_id_sample(event, &handle, &sample);
9309 perf_output_end(&handle);
9312 void perf_event_text_poke(const void *addr, const void *old_bytes,
9313 size_t old_len, const void *new_bytes, size_t new_len)
9315 struct perf_text_poke_event text_poke_event;
9318 if (!atomic_read(&nr_text_poke_events))
9321 tot = sizeof(text_poke_event.old_len) + old_len;
9322 tot += sizeof(text_poke_event.new_len) + new_len;
9323 pad = ALIGN(tot, sizeof(u64)) - tot;
9325 text_poke_event = (struct perf_text_poke_event){
9326 .old_bytes = old_bytes,
9327 .new_bytes = new_bytes,
9333 .type = PERF_RECORD_TEXT_POKE,
9334 .misc = PERF_RECORD_MISC_KERNEL,
9335 .size = sizeof(text_poke_event.event_id) + tot + pad,
9337 .addr = (unsigned long)addr,
9341 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9344 void perf_event_itrace_started(struct perf_event *event)
9346 event->attach_state |= PERF_ATTACH_ITRACE;
9349 static void perf_log_itrace_start(struct perf_event *event)
9351 struct perf_output_handle handle;
9352 struct perf_sample_data sample;
9353 struct perf_aux_event {
9354 struct perf_event_header header;
9361 event = event->parent;
9363 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9364 event->attach_state & PERF_ATTACH_ITRACE)
9367 rec.header.type = PERF_RECORD_ITRACE_START;
9368 rec.header.misc = 0;
9369 rec.header.size = sizeof(rec);
9370 rec.pid = perf_event_pid(event, current);
9371 rec.tid = perf_event_tid(event, current);
9373 perf_event_header__init_id(&rec.header, &sample, event);
9374 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9379 perf_output_put(&handle, rec);
9380 perf_event__output_id_sample(event, &handle, &sample);
9382 perf_output_end(&handle);
9385 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9387 struct perf_output_handle handle;
9388 struct perf_sample_data sample;
9389 struct perf_aux_event {
9390 struct perf_event_header header;
9396 event = event->parent;
9398 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9399 rec.header.misc = 0;
9400 rec.header.size = sizeof(rec);
9403 perf_event_header__init_id(&rec.header, &sample, event);
9404 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9409 perf_output_put(&handle, rec);
9410 perf_event__output_id_sample(event, &handle, &sample);
9412 perf_output_end(&handle);
9414 EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
9417 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9419 struct hw_perf_event *hwc = &event->hw;
9423 seq = __this_cpu_read(perf_throttled_seq);
9424 if (seq != hwc->interrupts_seq) {
9425 hwc->interrupts_seq = seq;
9426 hwc->interrupts = 1;
9429 if (unlikely(throttle &&
9430 hwc->interrupts > max_samples_per_tick)) {
9431 __this_cpu_inc(perf_throttled_count);
9432 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9433 hwc->interrupts = MAX_INTERRUPTS;
9434 perf_log_throttle(event, 0);
9439 if (event->attr.freq) {
9440 u64 now = perf_clock();
9441 s64 delta = now - hwc->freq_time_stamp;
9443 hwc->freq_time_stamp = now;
9445 if (delta > 0 && delta < 2*TICK_NSEC)
9446 perf_adjust_period(event, delta, hwc->last_period, true);
9452 int perf_event_account_interrupt(struct perf_event *event)
9454 return __perf_event_account_interrupt(event, 1);
9457 static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
9460 * Due to interrupt latency (AKA "skid"), we may enter the
9461 * kernel before taking an overflow, even if the PMU is only
9462 * counting user events.
9464 if (event->attr.exclude_kernel && !user_mode(regs))
9471 * Generic event overflow handling, sampling.
9474 static int __perf_event_overflow(struct perf_event *event,
9475 int throttle, struct perf_sample_data *data,
9476 struct pt_regs *regs)
9478 int events = atomic_read(&event->event_limit);
9482 * Non-sampling counters might still use the PMI to fold short
9483 * hardware counters, ignore those.
9485 if (unlikely(!is_sampling_event(event)))
9488 ret = __perf_event_account_interrupt(event, throttle);
9491 * XXX event_limit might not quite work as expected on inherited
9495 event->pending_kill = POLL_IN;
9496 if (events && atomic_dec_and_test(&event->event_limit)) {
9498 event->pending_kill = POLL_HUP;
9499 perf_event_disable_inatomic(event);
9502 if (event->attr.sigtrap) {
9504 * The desired behaviour of sigtrap vs invalid samples is a bit
9505 * tricky; on the one hand, one should not loose the SIGTRAP if
9506 * it is the first event, on the other hand, we should also not
9507 * trigger the WARN or override the data address.
9509 bool valid_sample = sample_is_allowed(event, regs);
9510 unsigned int pending_id = 1;
9513 pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1;
9514 if (!event->pending_sigtrap) {
9515 event->pending_sigtrap = pending_id;
9516 local_inc(&event->ctx->nr_pending);
9517 } else if (event->attr.exclude_kernel && valid_sample) {
9519 * Should not be able to return to user space without
9520 * consuming pending_sigtrap; with exceptions:
9522 * 1. Where !exclude_kernel, events can overflow again
9523 * in the kernel without returning to user space.
9525 * 2. Events that can overflow again before the IRQ-
9526 * work without user space progress (e.g. hrtimer).
9527 * To approximate progress (with false negatives),
9528 * check 32-bit hash of the current IP.
9530 WARN_ON_ONCE(event->pending_sigtrap != pending_id);
9533 event->pending_addr = 0;
9534 if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
9535 event->pending_addr = data->addr;
9536 irq_work_queue(&event->pending_irq);
9539 READ_ONCE(event->overflow_handler)(event, data, regs);
9541 if (*perf_event_fasync(event) && event->pending_kill) {
9542 event->pending_wakeup = 1;
9543 irq_work_queue(&event->pending_irq);
9549 int perf_event_overflow(struct perf_event *event,
9550 struct perf_sample_data *data,
9551 struct pt_regs *regs)
9553 return __perf_event_overflow(event, 1, data, regs);
9557 * Generic software event infrastructure
9560 struct swevent_htable {
9561 struct swevent_hlist *swevent_hlist;
9562 struct mutex hlist_mutex;
9565 /* Recursion avoidance in each contexts */
9566 int recursion[PERF_NR_CONTEXTS];
9569 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9572 * We directly increment event->count and keep a second value in
9573 * event->hw.period_left to count intervals. This period event
9574 * is kept in the range [-sample_period, 0] so that we can use the
9578 u64 perf_swevent_set_period(struct perf_event *event)
9580 struct hw_perf_event *hwc = &event->hw;
9581 u64 period = hwc->last_period;
9585 hwc->last_period = hwc->sample_period;
9587 old = local64_read(&hwc->period_left);
9593 nr = div64_u64(period + val, period);
9594 offset = nr * period;
9596 } while (!local64_try_cmpxchg(&hwc->period_left, &old, val));
9601 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9602 struct perf_sample_data *data,
9603 struct pt_regs *regs)
9605 struct hw_perf_event *hwc = &event->hw;
9609 overflow = perf_swevent_set_period(event);
9611 if (hwc->interrupts == MAX_INTERRUPTS)
9614 for (; overflow; overflow--) {
9615 if (__perf_event_overflow(event, throttle,
9618 * We inhibit the overflow from happening when
9619 * hwc->interrupts == MAX_INTERRUPTS.
9627 static void perf_swevent_event(struct perf_event *event, u64 nr,
9628 struct perf_sample_data *data,
9629 struct pt_regs *regs)
9631 struct hw_perf_event *hwc = &event->hw;
9633 local64_add(nr, &event->count);
9638 if (!is_sampling_event(event))
9641 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9643 return perf_swevent_overflow(event, 1, data, regs);
9645 data->period = event->hw.last_period;
9647 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9648 return perf_swevent_overflow(event, 1, data, regs);
9650 if (local64_add_negative(nr, &hwc->period_left))
9653 perf_swevent_overflow(event, 0, data, regs);
9656 static int perf_exclude_event(struct perf_event *event,
9657 struct pt_regs *regs)
9659 if (event->hw.state & PERF_HES_STOPPED)
9663 if (event->attr.exclude_user && user_mode(regs))
9666 if (event->attr.exclude_kernel && !user_mode(regs))
9673 static int perf_swevent_match(struct perf_event *event,
9674 enum perf_type_id type,
9676 struct perf_sample_data *data,
9677 struct pt_regs *regs)
9679 if (event->attr.type != type)
9682 if (event->attr.config != event_id)
9685 if (perf_exclude_event(event, regs))
9691 static inline u64 swevent_hash(u64 type, u32 event_id)
9693 u64 val = event_id | (type << 32);
9695 return hash_64(val, SWEVENT_HLIST_BITS);
9698 static inline struct hlist_head *
9699 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9701 u64 hash = swevent_hash(type, event_id);
9703 return &hlist->heads[hash];
9706 /* For the read side: events when they trigger */
9707 static inline struct hlist_head *
9708 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9710 struct swevent_hlist *hlist;
9712 hlist = rcu_dereference(swhash->swevent_hlist);
9716 return __find_swevent_head(hlist, type, event_id);
9719 /* For the event head insertion and removal in the hlist */
9720 static inline struct hlist_head *
9721 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9723 struct swevent_hlist *hlist;
9724 u32 event_id = event->attr.config;
9725 u64 type = event->attr.type;
9728 * Event scheduling is always serialized against hlist allocation
9729 * and release. Which makes the protected version suitable here.
9730 * The context lock guarantees that.
9732 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9733 lockdep_is_held(&event->ctx->lock));
9737 return __find_swevent_head(hlist, type, event_id);
9740 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9742 struct perf_sample_data *data,
9743 struct pt_regs *regs)
9745 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9746 struct perf_event *event;
9747 struct hlist_head *head;
9750 head = find_swevent_head_rcu(swhash, type, event_id);
9754 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9755 if (perf_swevent_match(event, type, event_id, data, regs))
9756 perf_swevent_event(event, nr, data, regs);
9762 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9764 int perf_swevent_get_recursion_context(void)
9766 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9768 return get_recursion_context(swhash->recursion);
9770 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9772 void perf_swevent_put_recursion_context(int rctx)
9774 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9776 put_recursion_context(swhash->recursion, rctx);
9779 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9781 struct perf_sample_data data;
9783 if (WARN_ON_ONCE(!regs))
9786 perf_sample_data_init(&data, addr, 0);
9787 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9790 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9794 preempt_disable_notrace();
9795 rctx = perf_swevent_get_recursion_context();
9796 if (unlikely(rctx < 0))
9799 ___perf_sw_event(event_id, nr, regs, addr);
9801 perf_swevent_put_recursion_context(rctx);
9803 preempt_enable_notrace();
9806 static void perf_swevent_read(struct perf_event *event)
9810 static int perf_swevent_add(struct perf_event *event, int flags)
9812 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9813 struct hw_perf_event *hwc = &event->hw;
9814 struct hlist_head *head;
9816 if (is_sampling_event(event)) {
9817 hwc->last_period = hwc->sample_period;
9818 perf_swevent_set_period(event);
9821 hwc->state = !(flags & PERF_EF_START);
9823 head = find_swevent_head(swhash, event);
9824 if (WARN_ON_ONCE(!head))
9827 hlist_add_head_rcu(&event->hlist_entry, head);
9828 perf_event_update_userpage(event);
9833 static void perf_swevent_del(struct perf_event *event, int flags)
9835 hlist_del_rcu(&event->hlist_entry);
9838 static void perf_swevent_start(struct perf_event *event, int flags)
9840 event->hw.state = 0;
9843 static void perf_swevent_stop(struct perf_event *event, int flags)
9845 event->hw.state = PERF_HES_STOPPED;
9848 /* Deref the hlist from the update side */
9849 static inline struct swevent_hlist *
9850 swevent_hlist_deref(struct swevent_htable *swhash)
9852 return rcu_dereference_protected(swhash->swevent_hlist,
9853 lockdep_is_held(&swhash->hlist_mutex));
9856 static void swevent_hlist_release(struct swevent_htable *swhash)
9858 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9863 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9864 kfree_rcu(hlist, rcu_head);
9867 static void swevent_hlist_put_cpu(int cpu)
9869 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9871 mutex_lock(&swhash->hlist_mutex);
9873 if (!--swhash->hlist_refcount)
9874 swevent_hlist_release(swhash);
9876 mutex_unlock(&swhash->hlist_mutex);
9879 static void swevent_hlist_put(void)
9883 for_each_possible_cpu(cpu)
9884 swevent_hlist_put_cpu(cpu);
9887 static int swevent_hlist_get_cpu(int cpu)
9889 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9892 mutex_lock(&swhash->hlist_mutex);
9893 if (!swevent_hlist_deref(swhash) &&
9894 cpumask_test_cpu(cpu, perf_online_mask)) {
9895 struct swevent_hlist *hlist;
9897 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9902 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9904 swhash->hlist_refcount++;
9906 mutex_unlock(&swhash->hlist_mutex);
9911 static int swevent_hlist_get(void)
9913 int err, cpu, failed_cpu;
9915 mutex_lock(&pmus_lock);
9916 for_each_possible_cpu(cpu) {
9917 err = swevent_hlist_get_cpu(cpu);
9923 mutex_unlock(&pmus_lock);
9926 for_each_possible_cpu(cpu) {
9927 if (cpu == failed_cpu)
9929 swevent_hlist_put_cpu(cpu);
9931 mutex_unlock(&pmus_lock);
9935 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9937 static void sw_perf_event_destroy(struct perf_event *event)
9939 u64 event_id = event->attr.config;
9941 WARN_ON(event->parent);
9943 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9944 swevent_hlist_put();
9947 static struct pmu perf_cpu_clock; /* fwd declaration */
9948 static struct pmu perf_task_clock;
9950 static int perf_swevent_init(struct perf_event *event)
9952 u64 event_id = event->attr.config;
9954 if (event->attr.type != PERF_TYPE_SOFTWARE)
9958 * no branch sampling for software events
9960 if (has_branch_stack(event))
9964 case PERF_COUNT_SW_CPU_CLOCK:
9965 event->attr.type = perf_cpu_clock.type;
9967 case PERF_COUNT_SW_TASK_CLOCK:
9968 event->attr.type = perf_task_clock.type;
9975 if (event_id >= PERF_COUNT_SW_MAX)
9978 if (!event->parent) {
9981 err = swevent_hlist_get();
9985 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9986 event->destroy = sw_perf_event_destroy;
9992 static struct pmu perf_swevent = {
9993 .task_ctx_nr = perf_sw_context,
9995 .capabilities = PERF_PMU_CAP_NO_NMI,
9997 .event_init = perf_swevent_init,
9998 .add = perf_swevent_add,
9999 .del = perf_swevent_del,
10000 .start = perf_swevent_start,
10001 .stop = perf_swevent_stop,
10002 .read = perf_swevent_read,
10005 #ifdef CONFIG_EVENT_TRACING
10007 static void tp_perf_event_destroy(struct perf_event *event)
10009 perf_trace_destroy(event);
10012 static int perf_tp_event_init(struct perf_event *event)
10016 if (event->attr.type != PERF_TYPE_TRACEPOINT)
10020 * no branch sampling for tracepoint events
10022 if (has_branch_stack(event))
10023 return -EOPNOTSUPP;
10025 err = perf_trace_init(event);
10029 event->destroy = tp_perf_event_destroy;
10034 static struct pmu perf_tracepoint = {
10035 .task_ctx_nr = perf_sw_context,
10037 .event_init = perf_tp_event_init,
10038 .add = perf_trace_add,
10039 .del = perf_trace_del,
10040 .start = perf_swevent_start,
10041 .stop = perf_swevent_stop,
10042 .read = perf_swevent_read,
10045 static int perf_tp_filter_match(struct perf_event *event,
10046 struct perf_sample_data *data)
10048 void *record = data->raw->frag.data;
10050 /* only top level events have filters set */
10052 event = event->parent;
10054 if (likely(!event->filter) || filter_match_preds(event->filter, record))
10059 static int perf_tp_event_match(struct perf_event *event,
10060 struct perf_sample_data *data,
10061 struct pt_regs *regs)
10063 if (event->hw.state & PERF_HES_STOPPED)
10066 * If exclude_kernel, only trace user-space tracepoints (uprobes)
10068 if (event->attr.exclude_kernel && !user_mode(regs))
10071 if (!perf_tp_filter_match(event, data))
10077 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
10078 struct trace_event_call *call, u64 count,
10079 struct pt_regs *regs, struct hlist_head *head,
10080 struct task_struct *task)
10082 if (bpf_prog_array_valid(call)) {
10083 *(struct pt_regs **)raw_data = regs;
10084 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
10085 perf_swevent_put_recursion_context(rctx);
10089 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
10092 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
10094 static void __perf_tp_event_target_task(u64 count, void *record,
10095 struct pt_regs *regs,
10096 struct perf_sample_data *data,
10097 struct perf_event *event)
10099 struct trace_entry *entry = record;
10101 if (event->attr.config != entry->type)
10103 /* Cannot deliver synchronous signal to other task. */
10104 if (event->attr.sigtrap)
10106 if (perf_tp_event_match(event, data, regs))
10107 perf_swevent_event(event, count, data, regs);
10110 static void perf_tp_event_target_task(u64 count, void *record,
10111 struct pt_regs *regs,
10112 struct perf_sample_data *data,
10113 struct perf_event_context *ctx)
10115 unsigned int cpu = smp_processor_id();
10116 struct pmu *pmu = &perf_tracepoint;
10117 struct perf_event *event, *sibling;
10119 perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) {
10120 __perf_tp_event_target_task(count, record, regs, data, event);
10121 for_each_sibling_event(sibling, event)
10122 __perf_tp_event_target_task(count, record, regs, data, sibling);
10125 perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) {
10126 __perf_tp_event_target_task(count, record, regs, data, event);
10127 for_each_sibling_event(sibling, event)
10128 __perf_tp_event_target_task(count, record, regs, data, sibling);
10132 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
10133 struct pt_regs *regs, struct hlist_head *head, int rctx,
10134 struct task_struct *task)
10136 struct perf_sample_data data;
10137 struct perf_event *event;
10139 struct perf_raw_record raw = {
10141 .size = entry_size,
10146 perf_sample_data_init(&data, 0, 0);
10147 perf_sample_save_raw_data(&data, &raw);
10149 perf_trace_buf_update(record, event_type);
10151 hlist_for_each_entry_rcu(event, head, hlist_entry) {
10152 if (perf_tp_event_match(event, &data, regs)) {
10153 perf_swevent_event(event, count, &data, regs);
10156 * Here use the same on-stack perf_sample_data,
10157 * some members in data are event-specific and
10158 * need to be re-computed for different sweveents.
10159 * Re-initialize data->sample_flags safely to avoid
10160 * the problem that next event skips preparing data
10161 * because data->sample_flags is set.
10163 perf_sample_data_init(&data, 0, 0);
10164 perf_sample_save_raw_data(&data, &raw);
10169 * If we got specified a target task, also iterate its context and
10170 * deliver this event there too.
10172 if (task && task != current) {
10173 struct perf_event_context *ctx;
10176 ctx = rcu_dereference(task->perf_event_ctxp);
10180 raw_spin_lock(&ctx->lock);
10181 perf_tp_event_target_task(count, record, regs, &data, ctx);
10182 raw_spin_unlock(&ctx->lock);
10187 perf_swevent_put_recursion_context(rctx);
10189 EXPORT_SYMBOL_GPL(perf_tp_event);
10191 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
10193 * Flags in config, used by dynamic PMU kprobe and uprobe
10194 * The flags should match following PMU_FORMAT_ATTR().
10196 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
10197 * if not set, create kprobe/uprobe
10199 * The following values specify a reference counter (or semaphore in the
10200 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
10201 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
10203 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
10204 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
10206 enum perf_probe_config {
10207 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
10208 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
10209 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
10212 PMU_FORMAT_ATTR(retprobe, "config:0");
10215 #ifdef CONFIG_KPROBE_EVENTS
10216 static struct attribute *kprobe_attrs[] = {
10217 &format_attr_retprobe.attr,
10221 static struct attribute_group kprobe_format_group = {
10223 .attrs = kprobe_attrs,
10226 static const struct attribute_group *kprobe_attr_groups[] = {
10227 &kprobe_format_group,
10231 static int perf_kprobe_event_init(struct perf_event *event);
10232 static struct pmu perf_kprobe = {
10233 .task_ctx_nr = perf_sw_context,
10234 .event_init = perf_kprobe_event_init,
10235 .add = perf_trace_add,
10236 .del = perf_trace_del,
10237 .start = perf_swevent_start,
10238 .stop = perf_swevent_stop,
10239 .read = perf_swevent_read,
10240 .attr_groups = kprobe_attr_groups,
10243 static int perf_kprobe_event_init(struct perf_event *event)
10248 if (event->attr.type != perf_kprobe.type)
10251 if (!perfmon_capable())
10255 * no branch sampling for probe events
10257 if (has_branch_stack(event))
10258 return -EOPNOTSUPP;
10260 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10261 err = perf_kprobe_init(event, is_retprobe);
10265 event->destroy = perf_kprobe_destroy;
10269 #endif /* CONFIG_KPROBE_EVENTS */
10271 #ifdef CONFIG_UPROBE_EVENTS
10272 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
10274 static struct attribute *uprobe_attrs[] = {
10275 &format_attr_retprobe.attr,
10276 &format_attr_ref_ctr_offset.attr,
10280 static struct attribute_group uprobe_format_group = {
10282 .attrs = uprobe_attrs,
10285 static const struct attribute_group *uprobe_attr_groups[] = {
10286 &uprobe_format_group,
10290 static int perf_uprobe_event_init(struct perf_event *event);
10291 static struct pmu perf_uprobe = {
10292 .task_ctx_nr = perf_sw_context,
10293 .event_init = perf_uprobe_event_init,
10294 .add = perf_trace_add,
10295 .del = perf_trace_del,
10296 .start = perf_swevent_start,
10297 .stop = perf_swevent_stop,
10298 .read = perf_swevent_read,
10299 .attr_groups = uprobe_attr_groups,
10302 static int perf_uprobe_event_init(struct perf_event *event)
10305 unsigned long ref_ctr_offset;
10308 if (event->attr.type != perf_uprobe.type)
10311 if (!perfmon_capable())
10315 * no branch sampling for probe events
10317 if (has_branch_stack(event))
10318 return -EOPNOTSUPP;
10320 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10321 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10322 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10326 event->destroy = perf_uprobe_destroy;
10330 #endif /* CONFIG_UPROBE_EVENTS */
10332 static inline void perf_tp_register(void)
10334 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10335 #ifdef CONFIG_KPROBE_EVENTS
10336 perf_pmu_register(&perf_kprobe, "kprobe", -1);
10338 #ifdef CONFIG_UPROBE_EVENTS
10339 perf_pmu_register(&perf_uprobe, "uprobe", -1);
10343 static void perf_event_free_filter(struct perf_event *event)
10345 ftrace_profile_free_filter(event);
10348 #ifdef CONFIG_BPF_SYSCALL
10349 static void bpf_overflow_handler(struct perf_event *event,
10350 struct perf_sample_data *data,
10351 struct pt_regs *regs)
10353 struct bpf_perf_event_data_kern ctx = {
10357 struct bpf_prog *prog;
10360 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10361 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10364 prog = READ_ONCE(event->prog);
10366 perf_prepare_sample(data, event, regs);
10367 ret = bpf_prog_run(prog, &ctx);
10371 __this_cpu_dec(bpf_prog_active);
10375 event->orig_overflow_handler(event, data, regs);
10378 static int perf_event_set_bpf_handler(struct perf_event *event,
10379 struct bpf_prog *prog,
10382 if (event->overflow_handler_context)
10383 /* hw breakpoint or kernel counter */
10389 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10392 if (event->attr.precise_ip &&
10393 prog->call_get_stack &&
10394 (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
10395 event->attr.exclude_callchain_kernel ||
10396 event->attr.exclude_callchain_user)) {
10398 * On perf_event with precise_ip, calling bpf_get_stack()
10399 * may trigger unwinder warnings and occasional crashes.
10400 * bpf_get_[stack|stackid] works around this issue by using
10401 * callchain attached to perf_sample_data. If the
10402 * perf_event does not full (kernel and user) callchain
10403 * attached to perf_sample_data, do not allow attaching BPF
10404 * program that calls bpf_get_[stack|stackid].
10409 event->prog = prog;
10410 event->bpf_cookie = bpf_cookie;
10411 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10412 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10416 static void perf_event_free_bpf_handler(struct perf_event *event)
10418 struct bpf_prog *prog = event->prog;
10423 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10424 event->prog = NULL;
10425 bpf_prog_put(prog);
10428 static int perf_event_set_bpf_handler(struct perf_event *event,
10429 struct bpf_prog *prog,
10432 return -EOPNOTSUPP;
10434 static void perf_event_free_bpf_handler(struct perf_event *event)
10440 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10441 * with perf_event_open()
10443 static inline bool perf_event_is_tracing(struct perf_event *event)
10445 if (event->pmu == &perf_tracepoint)
10447 #ifdef CONFIG_KPROBE_EVENTS
10448 if (event->pmu == &perf_kprobe)
10451 #ifdef CONFIG_UPROBE_EVENTS
10452 if (event->pmu == &perf_uprobe)
10458 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10461 bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp;
10463 if (!perf_event_is_tracing(event))
10464 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10466 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE;
10467 is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE;
10468 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10469 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10470 if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp)
10471 /* bpf programs can only be attached to u/kprobe or tracepoint */
10474 if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) ||
10475 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10476 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10479 if (prog->type == BPF_PROG_TYPE_KPROBE && prog->aux->sleepable && !is_uprobe)
10480 /* only uprobe programs are allowed to be sleepable */
10483 /* Kprobe override only works for kprobes, not uprobes. */
10484 if (prog->kprobe_override && !is_kprobe)
10487 if (is_tracepoint || is_syscall_tp) {
10488 int off = trace_event_get_offsets(event->tp_event);
10490 if (prog->aux->max_ctx_offset > off)
10494 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10497 void perf_event_free_bpf_prog(struct perf_event *event)
10499 if (!perf_event_is_tracing(event)) {
10500 perf_event_free_bpf_handler(event);
10503 perf_event_detach_bpf_prog(event);
10508 static inline void perf_tp_register(void)
10512 static void perf_event_free_filter(struct perf_event *event)
10516 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10522 void perf_event_free_bpf_prog(struct perf_event *event)
10525 #endif /* CONFIG_EVENT_TRACING */
10527 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10528 void perf_bp_event(struct perf_event *bp, void *data)
10530 struct perf_sample_data sample;
10531 struct pt_regs *regs = data;
10533 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10535 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10536 perf_swevent_event(bp, 1, &sample, regs);
10541 * Allocate a new address filter
10543 static struct perf_addr_filter *
10544 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10546 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10547 struct perf_addr_filter *filter;
10549 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10553 INIT_LIST_HEAD(&filter->entry);
10554 list_add_tail(&filter->entry, filters);
10559 static void free_filters_list(struct list_head *filters)
10561 struct perf_addr_filter *filter, *iter;
10563 list_for_each_entry_safe(filter, iter, filters, entry) {
10564 path_put(&filter->path);
10565 list_del(&filter->entry);
10571 * Free existing address filters and optionally install new ones
10573 static void perf_addr_filters_splice(struct perf_event *event,
10574 struct list_head *head)
10576 unsigned long flags;
10579 if (!has_addr_filter(event))
10582 /* don't bother with children, they don't have their own filters */
10586 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10588 list_splice_init(&event->addr_filters.list, &list);
10590 list_splice(head, &event->addr_filters.list);
10592 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10594 free_filters_list(&list);
10598 * Scan through mm's vmas and see if one of them matches the
10599 * @filter; if so, adjust filter's address range.
10600 * Called with mm::mmap_lock down for reading.
10602 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10603 struct mm_struct *mm,
10604 struct perf_addr_filter_range *fr)
10606 struct vm_area_struct *vma;
10607 VMA_ITERATOR(vmi, mm, 0);
10609 for_each_vma(vmi, vma) {
10613 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10619 * Update event's address range filters based on the
10620 * task's existing mappings, if any.
10622 static void perf_event_addr_filters_apply(struct perf_event *event)
10624 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10625 struct task_struct *task = READ_ONCE(event->ctx->task);
10626 struct perf_addr_filter *filter;
10627 struct mm_struct *mm = NULL;
10628 unsigned int count = 0;
10629 unsigned long flags;
10632 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10633 * will stop on the parent's child_mutex that our caller is also holding
10635 if (task == TASK_TOMBSTONE)
10638 if (ifh->nr_file_filters) {
10639 mm = get_task_mm(task);
10643 mmap_read_lock(mm);
10646 raw_spin_lock_irqsave(&ifh->lock, flags);
10647 list_for_each_entry(filter, &ifh->list, entry) {
10648 if (filter->path.dentry) {
10650 * Adjust base offset if the filter is associated to a
10651 * binary that needs to be mapped:
10653 event->addr_filter_ranges[count].start = 0;
10654 event->addr_filter_ranges[count].size = 0;
10656 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10658 event->addr_filter_ranges[count].start = filter->offset;
10659 event->addr_filter_ranges[count].size = filter->size;
10665 event->addr_filters_gen++;
10666 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10668 if (ifh->nr_file_filters) {
10669 mmap_read_unlock(mm);
10675 perf_event_stop(event, 1);
10679 * Address range filtering: limiting the data to certain
10680 * instruction address ranges. Filters are ioctl()ed to us from
10681 * userspace as ascii strings.
10683 * Filter string format:
10685 * ACTION RANGE_SPEC
10686 * where ACTION is one of the
10687 * * "filter": limit the trace to this region
10688 * * "start": start tracing from this address
10689 * * "stop": stop tracing at this address/region;
10691 * * for kernel addresses: <start address>[/<size>]
10692 * * for object files: <start address>[/<size>]@</path/to/object/file>
10694 * if <size> is not specified or is zero, the range is treated as a single
10695 * address; not valid for ACTION=="filter".
10709 IF_STATE_ACTION = 0,
10714 static const match_table_t if_tokens = {
10715 { IF_ACT_FILTER, "filter" },
10716 { IF_ACT_START, "start" },
10717 { IF_ACT_STOP, "stop" },
10718 { IF_SRC_FILE, "%u/%u@%s" },
10719 { IF_SRC_KERNEL, "%u/%u" },
10720 { IF_SRC_FILEADDR, "%u@%s" },
10721 { IF_SRC_KERNELADDR, "%u" },
10722 { IF_ACT_NONE, NULL },
10726 * Address filter string parser
10729 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10730 struct list_head *filters)
10732 struct perf_addr_filter *filter = NULL;
10733 char *start, *orig, *filename = NULL;
10734 substring_t args[MAX_OPT_ARGS];
10735 int state = IF_STATE_ACTION, token;
10736 unsigned int kernel = 0;
10739 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10743 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10744 static const enum perf_addr_filter_action_t actions[] = {
10745 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10746 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10747 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10754 /* filter definition begins */
10755 if (state == IF_STATE_ACTION) {
10756 filter = perf_addr_filter_new(event, filters);
10761 token = match_token(start, if_tokens, args);
10763 case IF_ACT_FILTER:
10766 if (state != IF_STATE_ACTION)
10769 filter->action = actions[token];
10770 state = IF_STATE_SOURCE;
10773 case IF_SRC_KERNELADDR:
10774 case IF_SRC_KERNEL:
10778 case IF_SRC_FILEADDR:
10780 if (state != IF_STATE_SOURCE)
10784 ret = kstrtoul(args[0].from, 0, &filter->offset);
10788 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10790 ret = kstrtoul(args[1].from, 0, &filter->size);
10795 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10796 int fpos = token == IF_SRC_FILE ? 2 : 1;
10799 filename = match_strdup(&args[fpos]);
10806 state = IF_STATE_END;
10814 * Filter definition is fully parsed, validate and install it.
10815 * Make sure that it doesn't contradict itself or the event's
10818 if (state == IF_STATE_END) {
10822 * ACTION "filter" must have a non-zero length region
10825 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10834 * For now, we only support file-based filters
10835 * in per-task events; doing so for CPU-wide
10836 * events requires additional context switching
10837 * trickery, since same object code will be
10838 * mapped at different virtual addresses in
10839 * different processes.
10842 if (!event->ctx->task)
10845 /* look up the path and grab its inode */
10846 ret = kern_path(filename, LOOKUP_FOLLOW,
10852 if (!filter->path.dentry ||
10853 !S_ISREG(d_inode(filter->path.dentry)
10857 event->addr_filters.nr_file_filters++;
10860 /* ready to consume more filters */
10863 state = IF_STATE_ACTION;
10869 if (state != IF_STATE_ACTION)
10879 free_filters_list(filters);
10886 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10888 LIST_HEAD(filters);
10892 * Since this is called in perf_ioctl() path, we're already holding
10895 lockdep_assert_held(&event->ctx->mutex);
10897 if (WARN_ON_ONCE(event->parent))
10900 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10902 goto fail_clear_files;
10904 ret = event->pmu->addr_filters_validate(&filters);
10906 goto fail_free_filters;
10908 /* remove existing filters, if any */
10909 perf_addr_filters_splice(event, &filters);
10911 /* install new filters */
10912 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10917 free_filters_list(&filters);
10920 event->addr_filters.nr_file_filters = 0;
10925 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10930 filter_str = strndup_user(arg, PAGE_SIZE);
10931 if (IS_ERR(filter_str))
10932 return PTR_ERR(filter_str);
10934 #ifdef CONFIG_EVENT_TRACING
10935 if (perf_event_is_tracing(event)) {
10936 struct perf_event_context *ctx = event->ctx;
10939 * Beware, here be dragons!!
10941 * the tracepoint muck will deadlock against ctx->mutex, but
10942 * the tracepoint stuff does not actually need it. So
10943 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10944 * already have a reference on ctx.
10946 * This can result in event getting moved to a different ctx,
10947 * but that does not affect the tracepoint state.
10949 mutex_unlock(&ctx->mutex);
10950 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10951 mutex_lock(&ctx->mutex);
10954 if (has_addr_filter(event))
10955 ret = perf_event_set_addr_filter(event, filter_str);
10962 * hrtimer based swevent callback
10965 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10967 enum hrtimer_restart ret = HRTIMER_RESTART;
10968 struct perf_sample_data data;
10969 struct pt_regs *regs;
10970 struct perf_event *event;
10973 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10975 if (event->state != PERF_EVENT_STATE_ACTIVE)
10976 return HRTIMER_NORESTART;
10978 event->pmu->read(event);
10980 perf_sample_data_init(&data, 0, event->hw.last_period);
10981 regs = get_irq_regs();
10983 if (regs && !perf_exclude_event(event, regs)) {
10984 if (!(event->attr.exclude_idle && is_idle_task(current)))
10985 if (__perf_event_overflow(event, 1, &data, regs))
10986 ret = HRTIMER_NORESTART;
10989 period = max_t(u64, 10000, event->hw.sample_period);
10990 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10995 static void perf_swevent_start_hrtimer(struct perf_event *event)
10997 struct hw_perf_event *hwc = &event->hw;
11000 if (!is_sampling_event(event))
11003 period = local64_read(&hwc->period_left);
11008 local64_set(&hwc->period_left, 0);
11010 period = max_t(u64, 10000, hwc->sample_period);
11012 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
11013 HRTIMER_MODE_REL_PINNED_HARD);
11016 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
11018 struct hw_perf_event *hwc = &event->hw;
11020 if (is_sampling_event(event)) {
11021 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
11022 local64_set(&hwc->period_left, ktime_to_ns(remaining));
11024 hrtimer_cancel(&hwc->hrtimer);
11028 static void perf_swevent_init_hrtimer(struct perf_event *event)
11030 struct hw_perf_event *hwc = &event->hw;
11032 if (!is_sampling_event(event))
11035 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
11036 hwc->hrtimer.function = perf_swevent_hrtimer;
11039 * Since hrtimers have a fixed rate, we can do a static freq->period
11040 * mapping and avoid the whole period adjust feedback stuff.
11042 if (event->attr.freq) {
11043 long freq = event->attr.sample_freq;
11045 event->attr.sample_period = NSEC_PER_SEC / freq;
11046 hwc->sample_period = event->attr.sample_period;
11047 local64_set(&hwc->period_left, hwc->sample_period);
11048 hwc->last_period = hwc->sample_period;
11049 event->attr.freq = 0;
11054 * Software event: cpu wall time clock
11057 static void cpu_clock_event_update(struct perf_event *event)
11062 now = local_clock();
11063 prev = local64_xchg(&event->hw.prev_count, now);
11064 local64_add(now - prev, &event->count);
11067 static void cpu_clock_event_start(struct perf_event *event, int flags)
11069 local64_set(&event->hw.prev_count, local_clock());
11070 perf_swevent_start_hrtimer(event);
11073 static void cpu_clock_event_stop(struct perf_event *event, int flags)
11075 perf_swevent_cancel_hrtimer(event);
11076 cpu_clock_event_update(event);
11079 static int cpu_clock_event_add(struct perf_event *event, int flags)
11081 if (flags & PERF_EF_START)
11082 cpu_clock_event_start(event, flags);
11083 perf_event_update_userpage(event);
11088 static void cpu_clock_event_del(struct perf_event *event, int flags)
11090 cpu_clock_event_stop(event, flags);
11093 static void cpu_clock_event_read(struct perf_event *event)
11095 cpu_clock_event_update(event);
11098 static int cpu_clock_event_init(struct perf_event *event)
11100 if (event->attr.type != perf_cpu_clock.type)
11103 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
11107 * no branch sampling for software events
11109 if (has_branch_stack(event))
11110 return -EOPNOTSUPP;
11112 perf_swevent_init_hrtimer(event);
11117 static struct pmu perf_cpu_clock = {
11118 .task_ctx_nr = perf_sw_context,
11120 .capabilities = PERF_PMU_CAP_NO_NMI,
11121 .dev = PMU_NULL_DEV,
11123 .event_init = cpu_clock_event_init,
11124 .add = cpu_clock_event_add,
11125 .del = cpu_clock_event_del,
11126 .start = cpu_clock_event_start,
11127 .stop = cpu_clock_event_stop,
11128 .read = cpu_clock_event_read,
11132 * Software event: task time clock
11135 static void task_clock_event_update(struct perf_event *event, u64 now)
11140 prev = local64_xchg(&event->hw.prev_count, now);
11141 delta = now - prev;
11142 local64_add(delta, &event->count);
11145 static void task_clock_event_start(struct perf_event *event, int flags)
11147 local64_set(&event->hw.prev_count, event->ctx->time);
11148 perf_swevent_start_hrtimer(event);
11151 static void task_clock_event_stop(struct perf_event *event, int flags)
11153 perf_swevent_cancel_hrtimer(event);
11154 task_clock_event_update(event, event->ctx->time);
11157 static int task_clock_event_add(struct perf_event *event, int flags)
11159 if (flags & PERF_EF_START)
11160 task_clock_event_start(event, flags);
11161 perf_event_update_userpage(event);
11166 static void task_clock_event_del(struct perf_event *event, int flags)
11168 task_clock_event_stop(event, PERF_EF_UPDATE);
11171 static void task_clock_event_read(struct perf_event *event)
11173 u64 now = perf_clock();
11174 u64 delta = now - event->ctx->timestamp;
11175 u64 time = event->ctx->time + delta;
11177 task_clock_event_update(event, time);
11180 static int task_clock_event_init(struct perf_event *event)
11182 if (event->attr.type != perf_task_clock.type)
11185 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
11189 * no branch sampling for software events
11191 if (has_branch_stack(event))
11192 return -EOPNOTSUPP;
11194 perf_swevent_init_hrtimer(event);
11199 static struct pmu perf_task_clock = {
11200 .task_ctx_nr = perf_sw_context,
11202 .capabilities = PERF_PMU_CAP_NO_NMI,
11203 .dev = PMU_NULL_DEV,
11205 .event_init = task_clock_event_init,
11206 .add = task_clock_event_add,
11207 .del = task_clock_event_del,
11208 .start = task_clock_event_start,
11209 .stop = task_clock_event_stop,
11210 .read = task_clock_event_read,
11213 static void perf_pmu_nop_void(struct pmu *pmu)
11217 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
11221 static int perf_pmu_nop_int(struct pmu *pmu)
11226 static int perf_event_nop_int(struct perf_event *event, u64 value)
11231 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
11233 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
11235 __this_cpu_write(nop_txn_flags, flags);
11237 if (flags & ~PERF_PMU_TXN_ADD)
11240 perf_pmu_disable(pmu);
11243 static int perf_pmu_commit_txn(struct pmu *pmu)
11245 unsigned int flags = __this_cpu_read(nop_txn_flags);
11247 __this_cpu_write(nop_txn_flags, 0);
11249 if (flags & ~PERF_PMU_TXN_ADD)
11252 perf_pmu_enable(pmu);
11256 static void perf_pmu_cancel_txn(struct pmu *pmu)
11258 unsigned int flags = __this_cpu_read(nop_txn_flags);
11260 __this_cpu_write(nop_txn_flags, 0);
11262 if (flags & ~PERF_PMU_TXN_ADD)
11265 perf_pmu_enable(pmu);
11268 static int perf_event_idx_default(struct perf_event *event)
11273 static void free_pmu_context(struct pmu *pmu)
11275 free_percpu(pmu->cpu_pmu_context);
11279 * Let userspace know that this PMU supports address range filtering:
11281 static ssize_t nr_addr_filters_show(struct device *dev,
11282 struct device_attribute *attr,
11285 struct pmu *pmu = dev_get_drvdata(dev);
11287 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
11289 DEVICE_ATTR_RO(nr_addr_filters);
11291 static struct idr pmu_idr;
11294 type_show(struct device *dev, struct device_attribute *attr, char *page)
11296 struct pmu *pmu = dev_get_drvdata(dev);
11298 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type);
11300 static DEVICE_ATTR_RO(type);
11303 perf_event_mux_interval_ms_show(struct device *dev,
11304 struct device_attribute *attr,
11307 struct pmu *pmu = dev_get_drvdata(dev);
11309 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms);
11312 static DEFINE_MUTEX(mux_interval_mutex);
11315 perf_event_mux_interval_ms_store(struct device *dev,
11316 struct device_attribute *attr,
11317 const char *buf, size_t count)
11319 struct pmu *pmu = dev_get_drvdata(dev);
11320 int timer, cpu, ret;
11322 ret = kstrtoint(buf, 0, &timer);
11329 /* same value, noting to do */
11330 if (timer == pmu->hrtimer_interval_ms)
11333 mutex_lock(&mux_interval_mutex);
11334 pmu->hrtimer_interval_ms = timer;
11336 /* update all cpuctx for this PMU */
11338 for_each_online_cpu(cpu) {
11339 struct perf_cpu_pmu_context *cpc;
11340 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11341 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11343 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc);
11345 cpus_read_unlock();
11346 mutex_unlock(&mux_interval_mutex);
11350 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11352 static struct attribute *pmu_dev_attrs[] = {
11353 &dev_attr_type.attr,
11354 &dev_attr_perf_event_mux_interval_ms.attr,
11357 ATTRIBUTE_GROUPS(pmu_dev);
11359 static int pmu_bus_running;
11360 static struct bus_type pmu_bus = {
11361 .name = "event_source",
11362 .dev_groups = pmu_dev_groups,
11365 static void pmu_dev_release(struct device *dev)
11370 static int pmu_dev_alloc(struct pmu *pmu)
11374 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11378 pmu->dev->groups = pmu->attr_groups;
11379 device_initialize(pmu->dev);
11381 dev_set_drvdata(pmu->dev, pmu);
11382 pmu->dev->bus = &pmu_bus;
11383 pmu->dev->parent = pmu->parent;
11384 pmu->dev->release = pmu_dev_release;
11386 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11390 ret = device_add(pmu->dev);
11394 /* For PMUs with address filters, throw in an extra attribute: */
11395 if (pmu->nr_addr_filters)
11396 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11401 if (pmu->attr_update)
11402 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11411 device_del(pmu->dev);
11414 put_device(pmu->dev);
11418 static struct lock_class_key cpuctx_mutex;
11419 static struct lock_class_key cpuctx_lock;
11421 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11423 int cpu, ret, max = PERF_TYPE_MAX;
11425 mutex_lock(&pmus_lock);
11427 pmu->pmu_disable_count = alloc_percpu(int);
11428 if (!pmu->pmu_disable_count)
11432 if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
11442 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11446 WARN_ON(type >= 0 && ret != type);
11451 if (pmu_bus_running && !pmu->dev) {
11452 ret = pmu_dev_alloc(pmu);
11458 pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
11459 if (!pmu->cpu_pmu_context)
11462 for_each_possible_cpu(cpu) {
11463 struct perf_cpu_pmu_context *cpc;
11465 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11466 __perf_init_event_pmu_context(&cpc->epc, pmu);
11467 __perf_mux_hrtimer_init(cpc, cpu);
11470 if (!pmu->start_txn) {
11471 if (pmu->pmu_enable) {
11473 * If we have pmu_enable/pmu_disable calls, install
11474 * transaction stubs that use that to try and batch
11475 * hardware accesses.
11477 pmu->start_txn = perf_pmu_start_txn;
11478 pmu->commit_txn = perf_pmu_commit_txn;
11479 pmu->cancel_txn = perf_pmu_cancel_txn;
11481 pmu->start_txn = perf_pmu_nop_txn;
11482 pmu->commit_txn = perf_pmu_nop_int;
11483 pmu->cancel_txn = perf_pmu_nop_void;
11487 if (!pmu->pmu_enable) {
11488 pmu->pmu_enable = perf_pmu_nop_void;
11489 pmu->pmu_disable = perf_pmu_nop_void;
11492 if (!pmu->check_period)
11493 pmu->check_period = perf_event_nop_int;
11495 if (!pmu->event_idx)
11496 pmu->event_idx = perf_event_idx_default;
11498 list_add_rcu(&pmu->entry, &pmus);
11499 atomic_set(&pmu->exclusive_cnt, 0);
11502 mutex_unlock(&pmus_lock);
11507 if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
11508 device_del(pmu->dev);
11509 put_device(pmu->dev);
11513 idr_remove(&pmu_idr, pmu->type);
11516 free_percpu(pmu->pmu_disable_count);
11519 EXPORT_SYMBOL_GPL(perf_pmu_register);
11521 void perf_pmu_unregister(struct pmu *pmu)
11523 mutex_lock(&pmus_lock);
11524 list_del_rcu(&pmu->entry);
11527 * We dereference the pmu list under both SRCU and regular RCU, so
11528 * synchronize against both of those.
11530 synchronize_srcu(&pmus_srcu);
11533 free_percpu(pmu->pmu_disable_count);
11534 idr_remove(&pmu_idr, pmu->type);
11535 if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
11536 if (pmu->nr_addr_filters)
11537 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11538 device_del(pmu->dev);
11539 put_device(pmu->dev);
11541 free_pmu_context(pmu);
11542 mutex_unlock(&pmus_lock);
11544 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11546 static inline bool has_extended_regs(struct perf_event *event)
11548 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11549 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11552 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11554 struct perf_event_context *ctx = NULL;
11557 if (!try_module_get(pmu->module))
11561 * A number of pmu->event_init() methods iterate the sibling_list to,
11562 * for example, validate if the group fits on the PMU. Therefore,
11563 * if this is a sibling event, acquire the ctx->mutex to protect
11564 * the sibling_list.
11566 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11568 * This ctx->mutex can nest when we're called through
11569 * inheritance. See the perf_event_ctx_lock_nested() comment.
11571 ctx = perf_event_ctx_lock_nested(event->group_leader,
11572 SINGLE_DEPTH_NESTING);
11577 ret = pmu->event_init(event);
11580 perf_event_ctx_unlock(event->group_leader, ctx);
11583 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11584 has_extended_regs(event))
11587 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11588 event_has_any_exclude_flag(event))
11591 if (ret && event->destroy)
11592 event->destroy(event);
11596 module_put(pmu->module);
11601 static struct pmu *perf_init_event(struct perf_event *event)
11603 bool extended_type = false;
11604 int idx, type, ret;
11607 idx = srcu_read_lock(&pmus_srcu);
11610 * Save original type before calling pmu->event_init() since certain
11611 * pmus overwrites event->attr.type to forward event to another pmu.
11613 event->orig_type = event->attr.type;
11615 /* Try parent's PMU first: */
11616 if (event->parent && event->parent->pmu) {
11617 pmu = event->parent->pmu;
11618 ret = perf_try_init_event(pmu, event);
11624 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11625 * are often aliases for PERF_TYPE_RAW.
11627 type = event->attr.type;
11628 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11629 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11631 type = PERF_TYPE_RAW;
11633 extended_type = true;
11634 event->attr.config &= PERF_HW_EVENT_MASK;
11640 pmu = idr_find(&pmu_idr, type);
11643 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11644 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11647 ret = perf_try_init_event(pmu, event);
11648 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11649 type = event->attr.type;
11654 pmu = ERR_PTR(ret);
11659 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11660 ret = perf_try_init_event(pmu, event);
11664 if (ret != -ENOENT) {
11665 pmu = ERR_PTR(ret);
11670 pmu = ERR_PTR(-ENOENT);
11672 srcu_read_unlock(&pmus_srcu, idx);
11677 static void attach_sb_event(struct perf_event *event)
11679 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11681 raw_spin_lock(&pel->lock);
11682 list_add_rcu(&event->sb_list, &pel->list);
11683 raw_spin_unlock(&pel->lock);
11687 * We keep a list of all !task (and therefore per-cpu) events
11688 * that need to receive side-band records.
11690 * This avoids having to scan all the various PMU per-cpu contexts
11691 * looking for them.
11693 static void account_pmu_sb_event(struct perf_event *event)
11695 if (is_sb_event(event))
11696 attach_sb_event(event);
11699 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11700 static void account_freq_event_nohz(void)
11702 #ifdef CONFIG_NO_HZ_FULL
11703 /* Lock so we don't race with concurrent unaccount */
11704 spin_lock(&nr_freq_lock);
11705 if (atomic_inc_return(&nr_freq_events) == 1)
11706 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11707 spin_unlock(&nr_freq_lock);
11711 static void account_freq_event(void)
11713 if (tick_nohz_full_enabled())
11714 account_freq_event_nohz();
11716 atomic_inc(&nr_freq_events);
11720 static void account_event(struct perf_event *event)
11727 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11729 if (event->attr.mmap || event->attr.mmap_data)
11730 atomic_inc(&nr_mmap_events);
11731 if (event->attr.build_id)
11732 atomic_inc(&nr_build_id_events);
11733 if (event->attr.comm)
11734 atomic_inc(&nr_comm_events);
11735 if (event->attr.namespaces)
11736 atomic_inc(&nr_namespaces_events);
11737 if (event->attr.cgroup)
11738 atomic_inc(&nr_cgroup_events);
11739 if (event->attr.task)
11740 atomic_inc(&nr_task_events);
11741 if (event->attr.freq)
11742 account_freq_event();
11743 if (event->attr.context_switch) {
11744 atomic_inc(&nr_switch_events);
11747 if (has_branch_stack(event))
11749 if (is_cgroup_event(event))
11751 if (event->attr.ksymbol)
11752 atomic_inc(&nr_ksymbol_events);
11753 if (event->attr.bpf_event)
11754 atomic_inc(&nr_bpf_events);
11755 if (event->attr.text_poke)
11756 atomic_inc(&nr_text_poke_events);
11760 * We need the mutex here because static_branch_enable()
11761 * must complete *before* the perf_sched_count increment
11764 if (atomic_inc_not_zero(&perf_sched_count))
11767 mutex_lock(&perf_sched_mutex);
11768 if (!atomic_read(&perf_sched_count)) {
11769 static_branch_enable(&perf_sched_events);
11771 * Guarantee that all CPUs observe they key change and
11772 * call the perf scheduling hooks before proceeding to
11773 * install events that need them.
11778 * Now that we have waited for the sync_sched(), allow further
11779 * increments to by-pass the mutex.
11781 atomic_inc(&perf_sched_count);
11782 mutex_unlock(&perf_sched_mutex);
11786 account_pmu_sb_event(event);
11790 * Allocate and initialize an event structure
11792 static struct perf_event *
11793 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11794 struct task_struct *task,
11795 struct perf_event *group_leader,
11796 struct perf_event *parent_event,
11797 perf_overflow_handler_t overflow_handler,
11798 void *context, int cgroup_fd)
11801 struct perf_event *event;
11802 struct hw_perf_event *hwc;
11803 long err = -EINVAL;
11806 if ((unsigned)cpu >= nr_cpu_ids) {
11807 if (!task || cpu != -1)
11808 return ERR_PTR(-EINVAL);
11810 if (attr->sigtrap && !task) {
11811 /* Requires a task: avoid signalling random tasks. */
11812 return ERR_PTR(-EINVAL);
11815 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11816 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11819 return ERR_PTR(-ENOMEM);
11822 * Single events are their own group leaders, with an
11823 * empty sibling list:
11826 group_leader = event;
11828 mutex_init(&event->child_mutex);
11829 INIT_LIST_HEAD(&event->child_list);
11831 INIT_LIST_HEAD(&event->event_entry);
11832 INIT_LIST_HEAD(&event->sibling_list);
11833 INIT_LIST_HEAD(&event->active_list);
11834 init_event_group(event);
11835 INIT_LIST_HEAD(&event->rb_entry);
11836 INIT_LIST_HEAD(&event->active_entry);
11837 INIT_LIST_HEAD(&event->addr_filters.list);
11838 INIT_HLIST_NODE(&event->hlist_entry);
11841 init_waitqueue_head(&event->waitq);
11842 init_irq_work(&event->pending_irq, perf_pending_irq);
11843 init_task_work(&event->pending_task, perf_pending_task);
11845 mutex_init(&event->mmap_mutex);
11846 raw_spin_lock_init(&event->addr_filters.lock);
11848 atomic_long_set(&event->refcount, 1);
11850 event->attr = *attr;
11851 event->group_leader = group_leader;
11855 event->parent = parent_event;
11857 event->ns = get_pid_ns(task_active_pid_ns(current));
11858 event->id = atomic64_inc_return(&perf_event_id);
11860 event->state = PERF_EVENT_STATE_INACTIVE;
11863 event->event_caps = parent_event->event_caps;
11866 event->attach_state = PERF_ATTACH_TASK;
11868 * XXX pmu::event_init needs to know what task to account to
11869 * and we cannot use the ctx information because we need the
11870 * pmu before we get a ctx.
11872 event->hw.target = get_task_struct(task);
11875 event->clock = &local_clock;
11877 event->clock = parent_event->clock;
11879 if (!overflow_handler && parent_event) {
11880 overflow_handler = parent_event->overflow_handler;
11881 context = parent_event->overflow_handler_context;
11882 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11883 if (overflow_handler == bpf_overflow_handler) {
11884 struct bpf_prog *prog = parent_event->prog;
11886 bpf_prog_inc(prog);
11887 event->prog = prog;
11888 event->orig_overflow_handler =
11889 parent_event->orig_overflow_handler;
11894 if (overflow_handler) {
11895 event->overflow_handler = overflow_handler;
11896 event->overflow_handler_context = context;
11897 } else if (is_write_backward(event)){
11898 event->overflow_handler = perf_event_output_backward;
11899 event->overflow_handler_context = NULL;
11901 event->overflow_handler = perf_event_output_forward;
11902 event->overflow_handler_context = NULL;
11905 perf_event__state_init(event);
11910 hwc->sample_period = attr->sample_period;
11911 if (attr->freq && attr->sample_freq)
11912 hwc->sample_period = 1;
11913 hwc->last_period = hwc->sample_period;
11915 local64_set(&hwc->period_left, hwc->sample_period);
11918 * We currently do not support PERF_SAMPLE_READ on inherited events.
11919 * See perf_output_read().
11921 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11924 if (!has_branch_stack(event))
11925 event->attr.branch_sample_type = 0;
11927 pmu = perf_init_event(event);
11929 err = PTR_ERR(pmu);
11934 * Disallow uncore-task events. Similarly, disallow uncore-cgroup
11935 * events (they don't make sense as the cgroup will be different
11936 * on other CPUs in the uncore mask).
11938 if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) {
11943 if (event->attr.aux_output &&
11944 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11949 if (cgroup_fd != -1) {
11950 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11955 err = exclusive_event_init(event);
11959 if (has_addr_filter(event)) {
11960 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11961 sizeof(struct perf_addr_filter_range),
11963 if (!event->addr_filter_ranges) {
11969 * Clone the parent's vma offsets: they are valid until exec()
11970 * even if the mm is not shared with the parent.
11972 if (event->parent) {
11973 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11975 raw_spin_lock_irq(&ifh->lock);
11976 memcpy(event->addr_filter_ranges,
11977 event->parent->addr_filter_ranges,
11978 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11979 raw_spin_unlock_irq(&ifh->lock);
11982 /* force hw sync on the address filters */
11983 event->addr_filters_gen = 1;
11986 if (!event->parent) {
11987 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11988 err = get_callchain_buffers(attr->sample_max_stack);
11990 goto err_addr_filters;
11994 err = security_perf_event_alloc(event);
11996 goto err_callchain_buffer;
11998 /* symmetric to unaccount_event() in _free_event() */
11999 account_event(event);
12003 err_callchain_buffer:
12004 if (!event->parent) {
12005 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
12006 put_callchain_buffers();
12009 kfree(event->addr_filter_ranges);
12012 exclusive_event_destroy(event);
12015 if (is_cgroup_event(event))
12016 perf_detach_cgroup(event);
12017 if (event->destroy)
12018 event->destroy(event);
12019 module_put(pmu->module);
12021 if (event->hw.target)
12022 put_task_struct(event->hw.target);
12023 call_rcu(&event->rcu_head, free_event_rcu);
12025 return ERR_PTR(err);
12028 static int perf_copy_attr(struct perf_event_attr __user *uattr,
12029 struct perf_event_attr *attr)
12034 /* Zero the full structure, so that a short copy will be nice. */
12035 memset(attr, 0, sizeof(*attr));
12037 ret = get_user(size, &uattr->size);
12041 /* ABI compatibility quirk: */
12043 size = PERF_ATTR_SIZE_VER0;
12044 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
12047 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
12056 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
12059 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
12062 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
12065 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
12066 u64 mask = attr->branch_sample_type;
12068 /* only using defined bits */
12069 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
12072 /* at least one branch bit must be set */
12073 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
12076 /* propagate priv level, when not set for branch */
12077 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
12079 /* exclude_kernel checked on syscall entry */
12080 if (!attr->exclude_kernel)
12081 mask |= PERF_SAMPLE_BRANCH_KERNEL;
12083 if (!attr->exclude_user)
12084 mask |= PERF_SAMPLE_BRANCH_USER;
12086 if (!attr->exclude_hv)
12087 mask |= PERF_SAMPLE_BRANCH_HV;
12089 * adjust user setting (for HW filter setup)
12091 attr->branch_sample_type = mask;
12093 /* privileged levels capture (kernel, hv): check permissions */
12094 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
12095 ret = perf_allow_kernel(attr);
12101 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
12102 ret = perf_reg_validate(attr->sample_regs_user);
12107 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
12108 if (!arch_perf_have_user_stack_dump())
12112 * We have __u32 type for the size, but so far
12113 * we can only use __u16 as maximum due to the
12114 * __u16 sample size limit.
12116 if (attr->sample_stack_user >= USHRT_MAX)
12118 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
12122 if (!attr->sample_max_stack)
12123 attr->sample_max_stack = sysctl_perf_event_max_stack;
12125 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
12126 ret = perf_reg_validate(attr->sample_regs_intr);
12128 #ifndef CONFIG_CGROUP_PERF
12129 if (attr->sample_type & PERF_SAMPLE_CGROUP)
12132 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
12133 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
12136 if (!attr->inherit && attr->inherit_thread)
12139 if (attr->remove_on_exec && attr->enable_on_exec)
12142 if (attr->sigtrap && !attr->remove_on_exec)
12149 put_user(sizeof(*attr), &uattr->size);
12154 static void mutex_lock_double(struct mutex *a, struct mutex *b)
12160 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
12164 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
12166 struct perf_buffer *rb = NULL;
12169 if (!output_event) {
12170 mutex_lock(&event->mmap_mutex);
12174 /* don't allow circular references */
12175 if (event == output_event)
12179 * Don't allow cross-cpu buffers
12181 if (output_event->cpu != event->cpu)
12185 * If its not a per-cpu rb, it must be the same task.
12187 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
12191 * Mixing clocks in the same buffer is trouble you don't need.
12193 if (output_event->clock != event->clock)
12197 * Either writing ring buffer from beginning or from end.
12198 * Mixing is not allowed.
12200 if (is_write_backward(output_event) != is_write_backward(event))
12204 * If both events generate aux data, they must be on the same PMU
12206 if (has_aux(event) && has_aux(output_event) &&
12207 event->pmu != output_event->pmu)
12211 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
12212 * output_event is already on rb->event_list, and the list iteration
12213 * restarts after every removal, it is guaranteed this new event is
12214 * observed *OR* if output_event is already removed, it's guaranteed we
12215 * observe !rb->mmap_count.
12217 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
12219 /* Can't redirect output if we've got an active mmap() */
12220 if (atomic_read(&event->mmap_count))
12223 if (output_event) {
12224 /* get the rb we want to redirect to */
12225 rb = ring_buffer_get(output_event);
12229 /* did we race against perf_mmap_close() */
12230 if (!atomic_read(&rb->mmap_count)) {
12231 ring_buffer_put(rb);
12236 ring_buffer_attach(event, rb);
12240 mutex_unlock(&event->mmap_mutex);
12242 mutex_unlock(&output_event->mmap_mutex);
12248 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
12250 bool nmi_safe = false;
12253 case CLOCK_MONOTONIC:
12254 event->clock = &ktime_get_mono_fast_ns;
12258 case CLOCK_MONOTONIC_RAW:
12259 event->clock = &ktime_get_raw_fast_ns;
12263 case CLOCK_REALTIME:
12264 event->clock = &ktime_get_real_ns;
12267 case CLOCK_BOOTTIME:
12268 event->clock = &ktime_get_boottime_ns;
12272 event->clock = &ktime_get_clocktai_ns;
12279 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12286 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12288 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12289 bool is_capable = perfmon_capable();
12291 if (attr->sigtrap) {
12293 * perf_event_attr::sigtrap sends signals to the other task.
12294 * Require the current task to also have CAP_KILL.
12297 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12301 * If the required capabilities aren't available, checks for
12302 * ptrace permissions: upgrade to ATTACH, since sending signals
12303 * can effectively change the target task.
12305 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12309 * Preserve ptrace permission check for backwards compatibility. The
12310 * ptrace check also includes checks that the current task and other
12311 * task have matching uids, and is therefore not done here explicitly.
12313 return is_capable || ptrace_may_access(task, ptrace_mode);
12317 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12319 * @attr_uptr: event_id type attributes for monitoring/sampling
12322 * @group_fd: group leader event fd
12323 * @flags: perf event open flags
12325 SYSCALL_DEFINE5(perf_event_open,
12326 struct perf_event_attr __user *, attr_uptr,
12327 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12329 struct perf_event *group_leader = NULL, *output_event = NULL;
12330 struct perf_event_pmu_context *pmu_ctx;
12331 struct perf_event *event, *sibling;
12332 struct perf_event_attr attr;
12333 struct perf_event_context *ctx;
12334 struct file *event_file = NULL;
12335 struct fd group = {NULL, 0};
12336 struct task_struct *task = NULL;
12339 int move_group = 0;
12341 int f_flags = O_RDWR;
12342 int cgroup_fd = -1;
12344 /* for future expandability... */
12345 if (flags & ~PERF_FLAG_ALL)
12348 err = perf_copy_attr(attr_uptr, &attr);
12352 /* Do we allow access to perf_event_open(2) ? */
12353 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12357 if (!attr.exclude_kernel) {
12358 err = perf_allow_kernel(&attr);
12363 if (attr.namespaces) {
12364 if (!perfmon_capable())
12369 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12372 if (attr.sample_period & (1ULL << 63))
12376 /* Only privileged users can get physical addresses */
12377 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12378 err = perf_allow_kernel(&attr);
12383 /* REGS_INTR can leak data, lockdown must prevent this */
12384 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12385 err = security_locked_down(LOCKDOWN_PERF);
12391 * In cgroup mode, the pid argument is used to pass the fd
12392 * opened to the cgroup directory in cgroupfs. The cpu argument
12393 * designates the cpu on which to monitor threads from that
12396 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12399 if (flags & PERF_FLAG_FD_CLOEXEC)
12400 f_flags |= O_CLOEXEC;
12402 event_fd = get_unused_fd_flags(f_flags);
12406 if (group_fd != -1) {
12407 err = perf_fget_light(group_fd, &group);
12410 group_leader = group.file->private_data;
12411 if (flags & PERF_FLAG_FD_OUTPUT)
12412 output_event = group_leader;
12413 if (flags & PERF_FLAG_FD_NO_GROUP)
12414 group_leader = NULL;
12417 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12418 task = find_lively_task_by_vpid(pid);
12419 if (IS_ERR(task)) {
12420 err = PTR_ERR(task);
12425 if (task && group_leader &&
12426 group_leader->attr.inherit != attr.inherit) {
12431 if (flags & PERF_FLAG_PID_CGROUP)
12434 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12435 NULL, NULL, cgroup_fd);
12436 if (IS_ERR(event)) {
12437 err = PTR_ERR(event);
12441 if (is_sampling_event(event)) {
12442 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12449 * Special case software events and allow them to be part of
12450 * any hardware group.
12454 if (attr.use_clockid) {
12455 err = perf_event_set_clock(event, attr.clockid);
12460 if (pmu->task_ctx_nr == perf_sw_context)
12461 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12464 err = down_read_interruptible(&task->signal->exec_update_lock);
12469 * We must hold exec_update_lock across this and any potential
12470 * perf_install_in_context() call for this new event to
12471 * serialize against exec() altering our credentials (and the
12472 * perf_event_exit_task() that could imply).
12475 if (!perf_check_permission(&attr, task))
12480 * Get the target context (task or percpu):
12482 ctx = find_get_context(task, event);
12484 err = PTR_ERR(ctx);
12488 mutex_lock(&ctx->mutex);
12490 if (ctx->task == TASK_TOMBSTONE) {
12497 * Check if the @cpu we're creating an event for is online.
12499 * We use the perf_cpu_context::ctx::mutex to serialize against
12500 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12502 struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
12504 if (!cpuctx->online) {
12510 if (group_leader) {
12514 * Do not allow a recursive hierarchy (this new sibling
12515 * becoming part of another group-sibling):
12517 if (group_leader->group_leader != group_leader)
12520 /* All events in a group should have the same clock */
12521 if (group_leader->clock != event->clock)
12525 * Make sure we're both events for the same CPU;
12526 * grouping events for different CPUs is broken; since
12527 * you can never concurrently schedule them anyhow.
12529 if (group_leader->cpu != event->cpu)
12533 * Make sure we're both on the same context; either task or cpu.
12535 if (group_leader->ctx != ctx)
12539 * Only a group leader can be exclusive or pinned
12541 if (attr.exclusive || attr.pinned)
12544 if (is_software_event(event) &&
12545 !in_software_context(group_leader)) {
12547 * If the event is a sw event, but the group_leader
12548 * is on hw context.
12550 * Allow the addition of software events to hw
12551 * groups, this is safe because software events
12552 * never fail to schedule.
12554 * Note the comment that goes with struct
12555 * perf_event_pmu_context.
12557 pmu = group_leader->pmu_ctx->pmu;
12558 } else if (!is_software_event(event)) {
12559 if (is_software_event(group_leader) &&
12560 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12562 * In case the group is a pure software group, and we
12563 * try to add a hardware event, move the whole group to
12564 * the hardware context.
12569 /* Don't allow group of multiple hw events from different pmus */
12570 if (!in_software_context(group_leader) &&
12571 group_leader->pmu_ctx->pmu != pmu)
12577 * Now that we're certain of the pmu; find the pmu_ctx.
12579 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12580 if (IS_ERR(pmu_ctx)) {
12581 err = PTR_ERR(pmu_ctx);
12584 event->pmu_ctx = pmu_ctx;
12586 if (output_event) {
12587 err = perf_event_set_output(event, output_event);
12592 if (!perf_event_validate_size(event)) {
12597 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12603 * Must be under the same ctx::mutex as perf_install_in_context(),
12604 * because we need to serialize with concurrent event creation.
12606 if (!exclusive_event_installable(event, ctx)) {
12611 WARN_ON_ONCE(ctx->parent_ctx);
12613 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags);
12614 if (IS_ERR(event_file)) {
12615 err = PTR_ERR(event_file);
12621 * This is the point on no return; we cannot fail hereafter. This is
12622 * where we start modifying current state.
12626 perf_remove_from_context(group_leader, 0);
12627 put_pmu_ctx(group_leader->pmu_ctx);
12629 for_each_sibling_event(sibling, group_leader) {
12630 perf_remove_from_context(sibling, 0);
12631 put_pmu_ctx(sibling->pmu_ctx);
12635 * Install the group siblings before the group leader.
12637 * Because a group leader will try and install the entire group
12638 * (through the sibling list, which is still in-tact), we can
12639 * end up with siblings installed in the wrong context.
12641 * By installing siblings first we NO-OP because they're not
12642 * reachable through the group lists.
12644 for_each_sibling_event(sibling, group_leader) {
12645 sibling->pmu_ctx = pmu_ctx;
12646 get_pmu_ctx(pmu_ctx);
12647 perf_event__state_init(sibling);
12648 perf_install_in_context(ctx, sibling, sibling->cpu);
12652 * Removing from the context ends up with disabled
12653 * event. What we want here is event in the initial
12654 * startup state, ready to be add into new context.
12656 group_leader->pmu_ctx = pmu_ctx;
12657 get_pmu_ctx(pmu_ctx);
12658 perf_event__state_init(group_leader);
12659 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12663 * Precalculate sample_data sizes; do while holding ctx::mutex such
12664 * that we're serialized against further additions and before
12665 * perf_install_in_context() which is the point the event is active and
12666 * can use these values.
12668 perf_event__header_size(event);
12669 perf_event__id_header_size(event);
12671 event->owner = current;
12673 perf_install_in_context(ctx, event, event->cpu);
12674 perf_unpin_context(ctx);
12676 mutex_unlock(&ctx->mutex);
12679 up_read(&task->signal->exec_update_lock);
12680 put_task_struct(task);
12683 mutex_lock(¤t->perf_event_mutex);
12684 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12685 mutex_unlock(¤t->perf_event_mutex);
12688 * Drop the reference on the group_event after placing the
12689 * new event on the sibling_list. This ensures destruction
12690 * of the group leader will find the pointer to itself in
12691 * perf_group_detach().
12694 fd_install(event_fd, event_file);
12698 put_pmu_ctx(event->pmu_ctx);
12699 event->pmu_ctx = NULL; /* _free_event() */
12701 mutex_unlock(&ctx->mutex);
12702 perf_unpin_context(ctx);
12706 up_read(&task->signal->exec_update_lock);
12711 put_task_struct(task);
12715 put_unused_fd(event_fd);
12720 * perf_event_create_kernel_counter
12722 * @attr: attributes of the counter to create
12723 * @cpu: cpu in which the counter is bound
12724 * @task: task to profile (NULL for percpu)
12725 * @overflow_handler: callback to trigger when we hit the event
12726 * @context: context data could be used in overflow_handler callback
12728 struct perf_event *
12729 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12730 struct task_struct *task,
12731 perf_overflow_handler_t overflow_handler,
12734 struct perf_event_pmu_context *pmu_ctx;
12735 struct perf_event_context *ctx;
12736 struct perf_event *event;
12741 * Grouping is not supported for kernel events, neither is 'AUX',
12742 * make sure the caller's intentions are adjusted.
12744 if (attr->aux_output)
12745 return ERR_PTR(-EINVAL);
12747 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12748 overflow_handler, context, -1);
12749 if (IS_ERR(event)) {
12750 err = PTR_ERR(event);
12754 /* Mark owner so we could distinguish it from user events. */
12755 event->owner = TASK_TOMBSTONE;
12758 if (pmu->task_ctx_nr == perf_sw_context)
12759 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12762 * Get the target context (task or percpu):
12764 ctx = find_get_context(task, event);
12766 err = PTR_ERR(ctx);
12770 WARN_ON_ONCE(ctx->parent_ctx);
12771 mutex_lock(&ctx->mutex);
12772 if (ctx->task == TASK_TOMBSTONE) {
12777 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12778 if (IS_ERR(pmu_ctx)) {
12779 err = PTR_ERR(pmu_ctx);
12782 event->pmu_ctx = pmu_ctx;
12786 * Check if the @cpu we're creating an event for is online.
12788 * We use the perf_cpu_context::ctx::mutex to serialize against
12789 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12791 struct perf_cpu_context *cpuctx =
12792 container_of(ctx, struct perf_cpu_context, ctx);
12793 if (!cpuctx->online) {
12799 if (!exclusive_event_installable(event, ctx)) {
12804 perf_install_in_context(ctx, event, event->cpu);
12805 perf_unpin_context(ctx);
12806 mutex_unlock(&ctx->mutex);
12811 put_pmu_ctx(pmu_ctx);
12812 event->pmu_ctx = NULL; /* _free_event() */
12814 mutex_unlock(&ctx->mutex);
12815 perf_unpin_context(ctx);
12820 return ERR_PTR(err);
12822 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12824 static void __perf_pmu_remove(struct perf_event_context *ctx,
12825 int cpu, struct pmu *pmu,
12826 struct perf_event_groups *groups,
12827 struct list_head *events)
12829 struct perf_event *event, *sibling;
12831 perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
12832 perf_remove_from_context(event, 0);
12833 put_pmu_ctx(event->pmu_ctx);
12834 list_add(&event->migrate_entry, events);
12836 for_each_sibling_event(sibling, event) {
12837 perf_remove_from_context(sibling, 0);
12838 put_pmu_ctx(sibling->pmu_ctx);
12839 list_add(&sibling->migrate_entry, events);
12844 static void __perf_pmu_install_event(struct pmu *pmu,
12845 struct perf_event_context *ctx,
12846 int cpu, struct perf_event *event)
12848 struct perf_event_pmu_context *epc;
12851 epc = find_get_pmu_context(pmu, ctx, event);
12852 event->pmu_ctx = epc;
12854 if (event->state >= PERF_EVENT_STATE_OFF)
12855 event->state = PERF_EVENT_STATE_INACTIVE;
12856 perf_install_in_context(ctx, event, cpu);
12859 static void __perf_pmu_install(struct perf_event_context *ctx,
12860 int cpu, struct pmu *pmu, struct list_head *events)
12862 struct perf_event *event, *tmp;
12865 * Re-instate events in 2 passes.
12867 * Skip over group leaders and only install siblings on this first
12868 * pass, siblings will not get enabled without a leader, however a
12869 * leader will enable its siblings, even if those are still on the old
12872 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12873 if (event->group_leader == event)
12876 list_del(&event->migrate_entry);
12877 __perf_pmu_install_event(pmu, ctx, cpu, event);
12881 * Once all the siblings are setup properly, install the group leaders
12884 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12885 list_del(&event->migrate_entry);
12886 __perf_pmu_install_event(pmu, ctx, cpu, event);
12890 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12892 struct perf_event_context *src_ctx, *dst_ctx;
12895 src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx;
12896 dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx;
12899 * See perf_event_ctx_lock() for comments on the details
12900 * of swizzling perf_event::ctx.
12902 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12904 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events);
12905 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events);
12907 if (!list_empty(&events)) {
12909 * Wait for the events to quiesce before re-instating them.
12913 __perf_pmu_install(dst_ctx, dst_cpu, pmu, &events);
12916 mutex_unlock(&dst_ctx->mutex);
12917 mutex_unlock(&src_ctx->mutex);
12919 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12921 static void sync_child_event(struct perf_event *child_event)
12923 struct perf_event *parent_event = child_event->parent;
12926 if (child_event->attr.inherit_stat) {
12927 struct task_struct *task = child_event->ctx->task;
12929 if (task && task != TASK_TOMBSTONE)
12930 perf_event_read_event(child_event, task);
12933 child_val = perf_event_count(child_event);
12936 * Add back the child's count to the parent's count:
12938 atomic64_add(child_val, &parent_event->child_count);
12939 atomic64_add(child_event->total_time_enabled,
12940 &parent_event->child_total_time_enabled);
12941 atomic64_add(child_event->total_time_running,
12942 &parent_event->child_total_time_running);
12946 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12948 struct perf_event *parent_event = event->parent;
12949 unsigned long detach_flags = 0;
12951 if (parent_event) {
12953 * Do not destroy the 'original' grouping; because of the
12954 * context switch optimization the original events could've
12955 * ended up in a random child task.
12957 * If we were to destroy the original group, all group related
12958 * operations would cease to function properly after this
12959 * random child dies.
12961 * Do destroy all inherited groups, we don't care about those
12962 * and being thorough is better.
12964 detach_flags = DETACH_GROUP | DETACH_CHILD;
12965 mutex_lock(&parent_event->child_mutex);
12968 perf_remove_from_context(event, detach_flags);
12970 raw_spin_lock_irq(&ctx->lock);
12971 if (event->state > PERF_EVENT_STATE_EXIT)
12972 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12973 raw_spin_unlock_irq(&ctx->lock);
12976 * Child events can be freed.
12978 if (parent_event) {
12979 mutex_unlock(&parent_event->child_mutex);
12981 * Kick perf_poll() for is_event_hup();
12983 perf_event_wakeup(parent_event);
12985 put_event(parent_event);
12990 * Parent events are governed by their filedesc, retain them.
12992 perf_event_wakeup(event);
12995 static void perf_event_exit_task_context(struct task_struct *child)
12997 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12998 struct perf_event *child_event, *next;
13000 WARN_ON_ONCE(child != current);
13002 child_ctx = perf_pin_task_context(child);
13007 * In order to reduce the amount of tricky in ctx tear-down, we hold
13008 * ctx::mutex over the entire thing. This serializes against almost
13009 * everything that wants to access the ctx.
13011 * The exception is sys_perf_event_open() /
13012 * perf_event_create_kernel_count() which does find_get_context()
13013 * without ctx::mutex (it cannot because of the move_group double mutex
13014 * lock thing). See the comments in perf_install_in_context().
13016 mutex_lock(&child_ctx->mutex);
13019 * In a single ctx::lock section, de-schedule the events and detach the
13020 * context from the task such that we cannot ever get it scheduled back
13023 raw_spin_lock_irq(&child_ctx->lock);
13024 task_ctx_sched_out(child_ctx, EVENT_ALL);
13027 * Now that the context is inactive, destroy the task <-> ctx relation
13028 * and mark the context dead.
13030 RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
13031 put_ctx(child_ctx); /* cannot be last */
13032 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
13033 put_task_struct(current); /* cannot be last */
13035 clone_ctx = unclone_ctx(child_ctx);
13036 raw_spin_unlock_irq(&child_ctx->lock);
13039 put_ctx(clone_ctx);
13042 * Report the task dead after unscheduling the events so that we
13043 * won't get any samples after PERF_RECORD_EXIT. We can however still
13044 * get a few PERF_RECORD_READ events.
13046 perf_event_task(child, child_ctx, 0);
13048 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
13049 perf_event_exit_event(child_event, child_ctx);
13051 mutex_unlock(&child_ctx->mutex);
13053 put_ctx(child_ctx);
13057 * When a child task exits, feed back event values to parent events.
13059 * Can be called with exec_update_lock held when called from
13060 * setup_new_exec().
13062 void perf_event_exit_task(struct task_struct *child)
13064 struct perf_event *event, *tmp;
13066 mutex_lock(&child->perf_event_mutex);
13067 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
13069 list_del_init(&event->owner_entry);
13072 * Ensure the list deletion is visible before we clear
13073 * the owner, closes a race against perf_release() where
13074 * we need to serialize on the owner->perf_event_mutex.
13076 smp_store_release(&event->owner, NULL);
13078 mutex_unlock(&child->perf_event_mutex);
13080 perf_event_exit_task_context(child);
13083 * The perf_event_exit_task_context calls perf_event_task
13084 * with child's task_ctx, which generates EXIT events for
13085 * child contexts and sets child->perf_event_ctxp[] to NULL.
13086 * At this point we need to send EXIT events to cpu contexts.
13088 perf_event_task(child, NULL, 0);
13091 static void perf_free_event(struct perf_event *event,
13092 struct perf_event_context *ctx)
13094 struct perf_event *parent = event->parent;
13096 if (WARN_ON_ONCE(!parent))
13099 mutex_lock(&parent->child_mutex);
13100 list_del_init(&event->child_list);
13101 mutex_unlock(&parent->child_mutex);
13105 raw_spin_lock_irq(&ctx->lock);
13106 perf_group_detach(event);
13107 list_del_event(event, ctx);
13108 raw_spin_unlock_irq(&ctx->lock);
13113 * Free a context as created by inheritance by perf_event_init_task() below,
13114 * used by fork() in case of fail.
13116 * Even though the task has never lived, the context and events have been
13117 * exposed through the child_list, so we must take care tearing it all down.
13119 void perf_event_free_task(struct task_struct *task)
13121 struct perf_event_context *ctx;
13122 struct perf_event *event, *tmp;
13124 ctx = rcu_access_pointer(task->perf_event_ctxp);
13128 mutex_lock(&ctx->mutex);
13129 raw_spin_lock_irq(&ctx->lock);
13131 * Destroy the task <-> ctx relation and mark the context dead.
13133 * This is important because even though the task hasn't been
13134 * exposed yet the context has been (through child_list).
13136 RCU_INIT_POINTER(task->perf_event_ctxp, NULL);
13137 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
13138 put_task_struct(task); /* cannot be last */
13139 raw_spin_unlock_irq(&ctx->lock);
13142 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
13143 perf_free_event(event, ctx);
13145 mutex_unlock(&ctx->mutex);
13148 * perf_event_release_kernel() could've stolen some of our
13149 * child events and still have them on its free_list. In that
13150 * case we must wait for these events to have been freed (in
13151 * particular all their references to this task must've been
13154 * Without this copy_process() will unconditionally free this
13155 * task (irrespective of its reference count) and
13156 * _free_event()'s put_task_struct(event->hw.target) will be a
13159 * Wait for all events to drop their context reference.
13161 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
13162 put_ctx(ctx); /* must be last */
13165 void perf_event_delayed_put(struct task_struct *task)
13167 WARN_ON_ONCE(task->perf_event_ctxp);
13170 struct file *perf_event_get(unsigned int fd)
13172 struct file *file = fget(fd);
13174 return ERR_PTR(-EBADF);
13176 if (file->f_op != &perf_fops) {
13178 return ERR_PTR(-EBADF);
13184 const struct perf_event *perf_get_event(struct file *file)
13186 if (file->f_op != &perf_fops)
13187 return ERR_PTR(-EINVAL);
13189 return file->private_data;
13192 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
13195 return ERR_PTR(-EINVAL);
13197 return &event->attr;
13201 * Inherit an event from parent task to child task.
13204 * - valid pointer on success
13205 * - NULL for orphaned events
13206 * - IS_ERR() on error
13208 static struct perf_event *
13209 inherit_event(struct perf_event *parent_event,
13210 struct task_struct *parent,
13211 struct perf_event_context *parent_ctx,
13212 struct task_struct *child,
13213 struct perf_event *group_leader,
13214 struct perf_event_context *child_ctx)
13216 enum perf_event_state parent_state = parent_event->state;
13217 struct perf_event_pmu_context *pmu_ctx;
13218 struct perf_event *child_event;
13219 unsigned long flags;
13222 * Instead of creating recursive hierarchies of events,
13223 * we link inherited events back to the original parent,
13224 * which has a filp for sure, which we use as the reference
13227 if (parent_event->parent)
13228 parent_event = parent_event->parent;
13230 child_event = perf_event_alloc(&parent_event->attr,
13233 group_leader, parent_event,
13235 if (IS_ERR(child_event))
13236 return child_event;
13238 pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
13239 if (IS_ERR(pmu_ctx)) {
13240 free_event(child_event);
13241 return ERR_CAST(pmu_ctx);
13243 child_event->pmu_ctx = pmu_ctx;
13246 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13247 * must be under the same lock in order to serialize against
13248 * perf_event_release_kernel(), such that either we must observe
13249 * is_orphaned_event() or they will observe us on the child_list.
13251 mutex_lock(&parent_event->child_mutex);
13252 if (is_orphaned_event(parent_event) ||
13253 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13254 mutex_unlock(&parent_event->child_mutex);
13255 /* task_ctx_data is freed with child_ctx */
13256 free_event(child_event);
13260 get_ctx(child_ctx);
13263 * Make the child state follow the state of the parent event,
13264 * not its attr.disabled bit. We hold the parent's mutex,
13265 * so we won't race with perf_event_{en, dis}able_family.
13267 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13268 child_event->state = PERF_EVENT_STATE_INACTIVE;
13270 child_event->state = PERF_EVENT_STATE_OFF;
13272 if (parent_event->attr.freq) {
13273 u64 sample_period = parent_event->hw.sample_period;
13274 struct hw_perf_event *hwc = &child_event->hw;
13276 hwc->sample_period = sample_period;
13277 hwc->last_period = sample_period;
13279 local64_set(&hwc->period_left, sample_period);
13282 child_event->ctx = child_ctx;
13283 child_event->overflow_handler = parent_event->overflow_handler;
13284 child_event->overflow_handler_context
13285 = parent_event->overflow_handler_context;
13288 * Precalculate sample_data sizes
13290 perf_event__header_size(child_event);
13291 perf_event__id_header_size(child_event);
13294 * Link it up in the child's context:
13296 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13297 add_event_to_ctx(child_event, child_ctx);
13298 child_event->attach_state |= PERF_ATTACH_CHILD;
13299 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13302 * Link this into the parent event's child list
13304 list_add_tail(&child_event->child_list, &parent_event->child_list);
13305 mutex_unlock(&parent_event->child_mutex);
13307 return child_event;
13311 * Inherits an event group.
13313 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13314 * This matches with perf_event_release_kernel() removing all child events.
13320 static int inherit_group(struct perf_event *parent_event,
13321 struct task_struct *parent,
13322 struct perf_event_context *parent_ctx,
13323 struct task_struct *child,
13324 struct perf_event_context *child_ctx)
13326 struct perf_event *leader;
13327 struct perf_event *sub;
13328 struct perf_event *child_ctr;
13330 leader = inherit_event(parent_event, parent, parent_ctx,
13331 child, NULL, child_ctx);
13332 if (IS_ERR(leader))
13333 return PTR_ERR(leader);
13335 * @leader can be NULL here because of is_orphaned_event(). In this
13336 * case inherit_event() will create individual events, similar to what
13337 * perf_group_detach() would do anyway.
13339 for_each_sibling_event(sub, parent_event) {
13340 child_ctr = inherit_event(sub, parent, parent_ctx,
13341 child, leader, child_ctx);
13342 if (IS_ERR(child_ctr))
13343 return PTR_ERR(child_ctr);
13345 if (sub->aux_event == parent_event && child_ctr &&
13346 !perf_get_aux_event(child_ctr, leader))
13353 * Creates the child task context and tries to inherit the event-group.
13355 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13356 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13357 * consistent with perf_event_release_kernel() removing all child events.
13364 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13365 struct perf_event_context *parent_ctx,
13366 struct task_struct *child,
13367 u64 clone_flags, int *inherited_all)
13369 struct perf_event_context *child_ctx;
13372 if (!event->attr.inherit ||
13373 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13374 /* Do not inherit if sigtrap and signal handlers were cleared. */
13375 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13376 *inherited_all = 0;
13380 child_ctx = child->perf_event_ctxp;
13383 * This is executed from the parent task context, so
13384 * inherit events that have been marked for cloning.
13385 * First allocate and initialize a context for the
13388 child_ctx = alloc_perf_context(child);
13392 child->perf_event_ctxp = child_ctx;
13395 ret = inherit_group(event, parent, parent_ctx, child, child_ctx);
13397 *inherited_all = 0;
13403 * Initialize the perf_event context in task_struct
13405 static int perf_event_init_context(struct task_struct *child, u64 clone_flags)
13407 struct perf_event_context *child_ctx, *parent_ctx;
13408 struct perf_event_context *cloned_ctx;
13409 struct perf_event *event;
13410 struct task_struct *parent = current;
13411 int inherited_all = 1;
13412 unsigned long flags;
13415 if (likely(!parent->perf_event_ctxp))
13419 * If the parent's context is a clone, pin it so it won't get
13420 * swapped under us.
13422 parent_ctx = perf_pin_task_context(parent);
13427 * No need to check if parent_ctx != NULL here; since we saw
13428 * it non-NULL earlier, the only reason for it to become NULL
13429 * is if we exit, and since we're currently in the middle of
13430 * a fork we can't be exiting at the same time.
13434 * Lock the parent list. No need to lock the child - not PID
13435 * hashed yet and not running, so nobody can access it.
13437 mutex_lock(&parent_ctx->mutex);
13440 * We dont have to disable NMIs - we are only looking at
13441 * the list, not manipulating it:
13443 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13444 ret = inherit_task_group(event, parent, parent_ctx,
13445 child, clone_flags, &inherited_all);
13451 * We can't hold ctx->lock when iterating the ->flexible_group list due
13452 * to allocations, but we need to prevent rotation because
13453 * rotate_ctx() will change the list from interrupt context.
13455 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13456 parent_ctx->rotate_disable = 1;
13457 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13459 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13460 ret = inherit_task_group(event, parent, parent_ctx,
13461 child, clone_flags, &inherited_all);
13466 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13467 parent_ctx->rotate_disable = 0;
13469 child_ctx = child->perf_event_ctxp;
13471 if (child_ctx && inherited_all) {
13473 * Mark the child context as a clone of the parent
13474 * context, or of whatever the parent is a clone of.
13476 * Note that if the parent is a clone, the holding of
13477 * parent_ctx->lock avoids it from being uncloned.
13479 cloned_ctx = parent_ctx->parent_ctx;
13481 child_ctx->parent_ctx = cloned_ctx;
13482 child_ctx->parent_gen = parent_ctx->parent_gen;
13484 child_ctx->parent_ctx = parent_ctx;
13485 child_ctx->parent_gen = parent_ctx->generation;
13487 get_ctx(child_ctx->parent_ctx);
13490 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13492 mutex_unlock(&parent_ctx->mutex);
13494 perf_unpin_context(parent_ctx);
13495 put_ctx(parent_ctx);
13501 * Initialize the perf_event context in task_struct
13503 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13507 child->perf_event_ctxp = NULL;
13508 mutex_init(&child->perf_event_mutex);
13509 INIT_LIST_HEAD(&child->perf_event_list);
13511 ret = perf_event_init_context(child, clone_flags);
13513 perf_event_free_task(child);
13520 static void __init perf_event_init_all_cpus(void)
13522 struct swevent_htable *swhash;
13523 struct perf_cpu_context *cpuctx;
13526 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13528 for_each_possible_cpu(cpu) {
13529 swhash = &per_cpu(swevent_htable, cpu);
13530 mutex_init(&swhash->hlist_mutex);
13532 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13533 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13535 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13537 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13538 __perf_event_init_context(&cpuctx->ctx);
13539 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
13540 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
13541 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
13542 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
13543 cpuctx->heap = cpuctx->heap_default;
13547 static void perf_swevent_init_cpu(unsigned int cpu)
13549 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13551 mutex_lock(&swhash->hlist_mutex);
13552 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13553 struct swevent_hlist *hlist;
13555 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13557 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13559 mutex_unlock(&swhash->hlist_mutex);
13562 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13563 static void __perf_event_exit_context(void *__info)
13565 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
13566 struct perf_event_context *ctx = __info;
13567 struct perf_event *event;
13569 raw_spin_lock(&ctx->lock);
13570 ctx_sched_out(ctx, EVENT_TIME);
13571 list_for_each_entry(event, &ctx->event_list, event_entry)
13572 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13573 raw_spin_unlock(&ctx->lock);
13576 static void perf_event_exit_cpu_context(int cpu)
13578 struct perf_cpu_context *cpuctx;
13579 struct perf_event_context *ctx;
13581 // XXX simplify cpuctx->online
13582 mutex_lock(&pmus_lock);
13583 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13584 ctx = &cpuctx->ctx;
13586 mutex_lock(&ctx->mutex);
13587 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13588 cpuctx->online = 0;
13589 mutex_unlock(&ctx->mutex);
13590 cpumask_clear_cpu(cpu, perf_online_mask);
13591 mutex_unlock(&pmus_lock);
13595 static void perf_event_exit_cpu_context(int cpu) { }
13599 int perf_event_init_cpu(unsigned int cpu)
13601 struct perf_cpu_context *cpuctx;
13602 struct perf_event_context *ctx;
13604 perf_swevent_init_cpu(cpu);
13606 mutex_lock(&pmus_lock);
13607 cpumask_set_cpu(cpu, perf_online_mask);
13608 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13609 ctx = &cpuctx->ctx;
13611 mutex_lock(&ctx->mutex);
13612 cpuctx->online = 1;
13613 mutex_unlock(&ctx->mutex);
13614 mutex_unlock(&pmus_lock);
13619 int perf_event_exit_cpu(unsigned int cpu)
13621 perf_event_exit_cpu_context(cpu);
13626 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13630 for_each_online_cpu(cpu)
13631 perf_event_exit_cpu(cpu);
13637 * Run the perf reboot notifier at the very last possible moment so that
13638 * the generic watchdog code runs as long as possible.
13640 static struct notifier_block perf_reboot_notifier = {
13641 .notifier_call = perf_reboot,
13642 .priority = INT_MIN,
13645 void __init perf_event_init(void)
13649 idr_init(&pmu_idr);
13651 perf_event_init_all_cpus();
13652 init_srcu_struct(&pmus_srcu);
13653 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13654 perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1);
13655 perf_pmu_register(&perf_task_clock, "task_clock", -1);
13656 perf_tp_register();
13657 perf_event_init_cpu(smp_processor_id());
13658 register_reboot_notifier(&perf_reboot_notifier);
13660 ret = init_hw_breakpoint();
13661 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13663 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13666 * Build time assertion that we keep the data_head at the intended
13667 * location. IOW, validation we got the __reserved[] size right.
13669 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13673 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13676 struct perf_pmu_events_attr *pmu_attr =
13677 container_of(attr, struct perf_pmu_events_attr, attr);
13679 if (pmu_attr->event_str)
13680 return sprintf(page, "%s\n", pmu_attr->event_str);
13684 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13686 static int __init perf_event_sysfs_init(void)
13691 mutex_lock(&pmus_lock);
13693 ret = bus_register(&pmu_bus);
13697 list_for_each_entry(pmu, &pmus, entry) {
13701 ret = pmu_dev_alloc(pmu);
13702 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13704 pmu_bus_running = 1;
13708 mutex_unlock(&pmus_lock);
13712 device_initcall(perf_event_sysfs_init);
13714 #ifdef CONFIG_CGROUP_PERF
13715 static struct cgroup_subsys_state *
13716 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13718 struct perf_cgroup *jc;
13720 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13722 return ERR_PTR(-ENOMEM);
13724 jc->info = alloc_percpu(struct perf_cgroup_info);
13727 return ERR_PTR(-ENOMEM);
13733 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13735 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13737 free_percpu(jc->info);
13741 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13743 perf_event_cgroup(css->cgroup);
13747 static int __perf_cgroup_move(void *info)
13749 struct task_struct *task = info;
13752 perf_cgroup_switch(task);
13758 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13760 struct task_struct *task;
13761 struct cgroup_subsys_state *css;
13763 cgroup_taskset_for_each(task, css, tset)
13764 task_function_call(task, __perf_cgroup_move, task);
13767 struct cgroup_subsys perf_event_cgrp_subsys = {
13768 .css_alloc = perf_cgroup_css_alloc,
13769 .css_free = perf_cgroup_css_free,
13770 .css_online = perf_cgroup_css_online,
13771 .attach = perf_cgroup_attach,
13773 * Implicitly enable on dfl hierarchy so that perf events can
13774 * always be filtered by cgroup2 path as long as perf_event
13775 * controller is not mounted on a legacy hierarchy.
13777 .implicit_on_dfl = true,
13780 #endif /* CONFIG_CGROUP_PERF */
13782 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);