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++;
1957 group_leader->group_generation++;
1959 perf_event__header_size(group_leader);
1961 for_each_sibling_event(pos, group_leader)
1962 perf_event__header_size(pos);
1966 * Remove an event from the lists for its context.
1967 * Must be called with ctx->mutex and ctx->lock held.
1970 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1972 WARN_ON_ONCE(event->ctx != ctx);
1973 lockdep_assert_held(&ctx->lock);
1976 * We can have double detach due to exit/hot-unplug + close.
1978 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1981 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1984 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
1986 if (event->attr.inherit_stat)
1989 list_del_rcu(&event->event_entry);
1991 if (event->group_leader == event)
1992 del_event_from_groups(event, ctx);
1995 * If event was in error state, then keep it
1996 * that way, otherwise bogus counts will be
1997 * returned on read(). The only way to get out
1998 * of error state is by explicit re-enabling
2001 if (event->state > PERF_EVENT_STATE_OFF) {
2002 perf_cgroup_event_disable(event, ctx);
2003 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2007 event->pmu_ctx->nr_events--;
2011 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2013 if (!has_aux(aux_event))
2016 if (!event->pmu->aux_output_match)
2019 return event->pmu->aux_output_match(aux_event);
2022 static void put_event(struct perf_event *event);
2023 static void event_sched_out(struct perf_event *event,
2024 struct perf_event_context *ctx);
2026 static void perf_put_aux_event(struct perf_event *event)
2028 struct perf_event_context *ctx = event->ctx;
2029 struct perf_event *iter;
2032 * If event uses aux_event tear down the link
2034 if (event->aux_event) {
2035 iter = event->aux_event;
2036 event->aux_event = NULL;
2042 * If the event is an aux_event, tear down all links to
2043 * it from other events.
2045 for_each_sibling_event(iter, event->group_leader) {
2046 if (iter->aux_event != event)
2049 iter->aux_event = NULL;
2053 * If it's ACTIVE, schedule it out and put it into ERROR
2054 * state so that we don't try to schedule it again. Note
2055 * that perf_event_enable() will clear the ERROR status.
2057 event_sched_out(iter, ctx);
2058 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2062 static bool perf_need_aux_event(struct perf_event *event)
2064 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2067 static int perf_get_aux_event(struct perf_event *event,
2068 struct perf_event *group_leader)
2071 * Our group leader must be an aux event if we want to be
2072 * an aux_output. This way, the aux event will precede its
2073 * aux_output events in the group, and therefore will always
2080 * aux_output and aux_sample_size are mutually exclusive.
2082 if (event->attr.aux_output && event->attr.aux_sample_size)
2085 if (event->attr.aux_output &&
2086 !perf_aux_output_match(event, group_leader))
2089 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2092 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2096 * Link aux_outputs to their aux event; this is undone in
2097 * perf_group_detach() by perf_put_aux_event(). When the
2098 * group in torn down, the aux_output events loose their
2099 * link to the aux_event and can't schedule any more.
2101 event->aux_event = group_leader;
2106 static inline struct list_head *get_event_list(struct perf_event *event)
2108 return event->attr.pinned ? &event->pmu_ctx->pinned_active :
2109 &event->pmu_ctx->flexible_active;
2113 * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2114 * cannot exist on their own, schedule them out and move them into the ERROR
2115 * state. Also see _perf_event_enable(), it will not be able to recover
2118 static inline void perf_remove_sibling_event(struct perf_event *event)
2120 event_sched_out(event, event->ctx);
2121 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2124 static void perf_group_detach(struct perf_event *event)
2126 struct perf_event *leader = event->group_leader;
2127 struct perf_event *sibling, *tmp;
2128 struct perf_event_context *ctx = event->ctx;
2130 lockdep_assert_held(&ctx->lock);
2133 * We can have double detach due to exit/hot-unplug + close.
2135 if (!(event->attach_state & PERF_ATTACH_GROUP))
2138 event->attach_state &= ~PERF_ATTACH_GROUP;
2140 perf_put_aux_event(event);
2143 * If this is a sibling, remove it from its group.
2145 if (leader != event) {
2146 list_del_init(&event->sibling_list);
2147 event->group_leader->nr_siblings--;
2148 event->group_leader->group_generation++;
2153 * If this was a group event with sibling events then
2154 * upgrade the siblings to singleton events by adding them
2155 * to whatever list we are on.
2157 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2159 if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2160 perf_remove_sibling_event(sibling);
2162 sibling->group_leader = sibling;
2163 list_del_init(&sibling->sibling_list);
2165 /* Inherit group flags from the previous leader */
2166 sibling->group_caps = event->group_caps;
2168 if (sibling->attach_state & PERF_ATTACH_CONTEXT) {
2169 add_event_to_groups(sibling, event->ctx);
2171 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2172 list_add_tail(&sibling->active_list, get_event_list(sibling));
2175 WARN_ON_ONCE(sibling->ctx != event->ctx);
2179 for_each_sibling_event(tmp, leader)
2180 perf_event__header_size(tmp);
2182 perf_event__header_size(leader);
2185 static void sync_child_event(struct perf_event *child_event);
2187 static void perf_child_detach(struct perf_event *event)
2189 struct perf_event *parent_event = event->parent;
2191 if (!(event->attach_state & PERF_ATTACH_CHILD))
2194 event->attach_state &= ~PERF_ATTACH_CHILD;
2196 if (WARN_ON_ONCE(!parent_event))
2199 lockdep_assert_held(&parent_event->child_mutex);
2201 sync_child_event(event);
2202 list_del_init(&event->child_list);
2205 static bool is_orphaned_event(struct perf_event *event)
2207 return event->state == PERF_EVENT_STATE_DEAD;
2211 event_filter_match(struct perf_event *event)
2213 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2214 perf_cgroup_match(event);
2218 event_sched_out(struct perf_event *event, struct perf_event_context *ctx)
2220 struct perf_event_pmu_context *epc = event->pmu_ctx;
2221 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2222 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2224 // XXX cpc serialization, probably per-cpu IRQ disabled
2226 WARN_ON_ONCE(event->ctx != ctx);
2227 lockdep_assert_held(&ctx->lock);
2229 if (event->state != PERF_EVENT_STATE_ACTIVE)
2233 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2234 * we can schedule events _OUT_ individually through things like
2235 * __perf_remove_from_context().
2237 list_del_init(&event->active_list);
2239 perf_pmu_disable(event->pmu);
2241 event->pmu->del(event, 0);
2244 if (event->pending_disable) {
2245 event->pending_disable = 0;
2246 perf_cgroup_event_disable(event, ctx);
2247 state = PERF_EVENT_STATE_OFF;
2250 if (event->pending_sigtrap) {
2253 event->pending_sigtrap = 0;
2254 if (state != PERF_EVENT_STATE_OFF &&
2255 !event->pending_work) {
2256 event->pending_work = 1;
2258 WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount));
2259 task_work_add(current, &event->pending_task, TWA_RESUME);
2262 local_dec(&event->ctx->nr_pending);
2265 perf_event_set_state(event, state);
2267 if (!is_software_event(event))
2268 cpc->active_oncpu--;
2269 if (event->attr.freq && event->attr.sample_freq)
2271 if (event->attr.exclusive || !cpc->active_oncpu)
2274 perf_pmu_enable(event->pmu);
2278 group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx)
2280 struct perf_event *event;
2282 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2285 perf_assert_pmu_disabled(group_event->pmu_ctx->pmu);
2287 event_sched_out(group_event, ctx);
2290 * Schedule out siblings (if any):
2292 for_each_sibling_event(event, group_event)
2293 event_sched_out(event, ctx);
2296 #define DETACH_GROUP 0x01UL
2297 #define DETACH_CHILD 0x02UL
2298 #define DETACH_DEAD 0x04UL
2301 * Cross CPU call to remove a performance event
2303 * We disable the event on the hardware level first. After that we
2304 * remove it from the context list.
2307 __perf_remove_from_context(struct perf_event *event,
2308 struct perf_cpu_context *cpuctx,
2309 struct perf_event_context *ctx,
2312 struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
2313 unsigned long flags = (unsigned long)info;
2315 if (ctx->is_active & EVENT_TIME) {
2316 update_context_time(ctx);
2317 update_cgrp_time_from_cpuctx(cpuctx, false);
2321 * Ensure event_sched_out() switches to OFF, at the very least
2322 * this avoids raising perf_pending_task() at this time.
2324 if (flags & DETACH_DEAD)
2325 event->pending_disable = 1;
2326 event_sched_out(event, ctx);
2327 if (flags & DETACH_GROUP)
2328 perf_group_detach(event);
2329 if (flags & DETACH_CHILD)
2330 perf_child_detach(event);
2331 list_del_event(event, ctx);
2332 if (flags & DETACH_DEAD)
2333 event->state = PERF_EVENT_STATE_DEAD;
2335 if (!pmu_ctx->nr_events) {
2336 pmu_ctx->rotate_necessary = 0;
2338 if (ctx->task && ctx->is_active) {
2339 struct perf_cpu_pmu_context *cpc;
2341 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
2342 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
2343 cpc->task_epc = NULL;
2347 if (!ctx->nr_events && ctx->is_active) {
2348 if (ctx == &cpuctx->ctx)
2349 update_cgrp_time_from_cpuctx(cpuctx, true);
2353 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2354 cpuctx->task_ctx = NULL;
2360 * Remove the event from a task's (or a CPU's) list of events.
2362 * If event->ctx is a cloned context, callers must make sure that
2363 * every task struct that event->ctx->task could possibly point to
2364 * remains valid. This is OK when called from perf_release since
2365 * that only calls us on the top-level context, which can't be a clone.
2366 * When called from perf_event_exit_task, it's OK because the
2367 * context has been detached from its task.
2369 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2371 struct perf_event_context *ctx = event->ctx;
2373 lockdep_assert_held(&ctx->mutex);
2376 * Because of perf_event_exit_task(), perf_remove_from_context() ought
2377 * to work in the face of TASK_TOMBSTONE, unlike every other
2378 * event_function_call() user.
2380 raw_spin_lock_irq(&ctx->lock);
2381 if (!ctx->is_active) {
2382 __perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context),
2383 ctx, (void *)flags);
2384 raw_spin_unlock_irq(&ctx->lock);
2387 raw_spin_unlock_irq(&ctx->lock);
2389 event_function_call(event, __perf_remove_from_context, (void *)flags);
2393 * Cross CPU call to disable a performance event
2395 static void __perf_event_disable(struct perf_event *event,
2396 struct perf_cpu_context *cpuctx,
2397 struct perf_event_context *ctx,
2400 if (event->state < PERF_EVENT_STATE_INACTIVE)
2403 if (ctx->is_active & EVENT_TIME) {
2404 update_context_time(ctx);
2405 update_cgrp_time_from_event(event);
2408 perf_pmu_disable(event->pmu_ctx->pmu);
2410 if (event == event->group_leader)
2411 group_sched_out(event, ctx);
2413 event_sched_out(event, ctx);
2415 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2416 perf_cgroup_event_disable(event, ctx);
2418 perf_pmu_enable(event->pmu_ctx->pmu);
2424 * If event->ctx is a cloned context, callers must make sure that
2425 * every task struct that event->ctx->task could possibly point to
2426 * remains valid. This condition is satisfied when called through
2427 * perf_event_for_each_child or perf_event_for_each because they
2428 * hold the top-level event's child_mutex, so any descendant that
2429 * goes to exit will block in perf_event_exit_event().
2431 * When called from perf_pending_irq it's OK because event->ctx
2432 * is the current context on this CPU and preemption is disabled,
2433 * hence we can't get into perf_event_task_sched_out for this context.
2435 static void _perf_event_disable(struct perf_event *event)
2437 struct perf_event_context *ctx = event->ctx;
2439 raw_spin_lock_irq(&ctx->lock);
2440 if (event->state <= PERF_EVENT_STATE_OFF) {
2441 raw_spin_unlock_irq(&ctx->lock);
2444 raw_spin_unlock_irq(&ctx->lock);
2446 event_function_call(event, __perf_event_disable, NULL);
2449 void perf_event_disable_local(struct perf_event *event)
2451 event_function_local(event, __perf_event_disable, NULL);
2455 * Strictly speaking kernel users cannot create groups and therefore this
2456 * interface does not need the perf_event_ctx_lock() magic.
2458 void perf_event_disable(struct perf_event *event)
2460 struct perf_event_context *ctx;
2462 ctx = perf_event_ctx_lock(event);
2463 _perf_event_disable(event);
2464 perf_event_ctx_unlock(event, ctx);
2466 EXPORT_SYMBOL_GPL(perf_event_disable);
2468 void perf_event_disable_inatomic(struct perf_event *event)
2470 event->pending_disable = 1;
2471 irq_work_queue(&event->pending_irq);
2474 #define MAX_INTERRUPTS (~0ULL)
2476 static void perf_log_throttle(struct perf_event *event, int enable);
2477 static void perf_log_itrace_start(struct perf_event *event);
2480 event_sched_in(struct perf_event *event, struct perf_event_context *ctx)
2482 struct perf_event_pmu_context *epc = event->pmu_ctx;
2483 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2486 WARN_ON_ONCE(event->ctx != ctx);
2488 lockdep_assert_held(&ctx->lock);
2490 if (event->state <= PERF_EVENT_STATE_OFF)
2493 WRITE_ONCE(event->oncpu, smp_processor_id());
2495 * Order event::oncpu write to happen before the ACTIVE state is
2496 * visible. This allows perf_event_{stop,read}() to observe the correct
2497 * ->oncpu if it sees ACTIVE.
2500 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2503 * Unthrottle events, since we scheduled we might have missed several
2504 * ticks already, also for a heavily scheduling task there is little
2505 * guarantee it'll get a tick in a timely manner.
2507 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2508 perf_log_throttle(event, 1);
2509 event->hw.interrupts = 0;
2512 perf_pmu_disable(event->pmu);
2514 perf_log_itrace_start(event);
2516 if (event->pmu->add(event, PERF_EF_START)) {
2517 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2523 if (!is_software_event(event))
2524 cpc->active_oncpu++;
2525 if (event->attr.freq && event->attr.sample_freq)
2528 if (event->attr.exclusive)
2532 perf_pmu_enable(event->pmu);
2538 group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx)
2540 struct perf_event *event, *partial_group = NULL;
2541 struct pmu *pmu = group_event->pmu_ctx->pmu;
2543 if (group_event->state == PERF_EVENT_STATE_OFF)
2546 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2548 if (event_sched_in(group_event, ctx))
2552 * Schedule in siblings as one group (if any):
2554 for_each_sibling_event(event, group_event) {
2555 if (event_sched_in(event, ctx)) {
2556 partial_group = event;
2561 if (!pmu->commit_txn(pmu))
2566 * Groups can be scheduled in as one unit only, so undo any
2567 * partial group before returning:
2568 * The events up to the failed event are scheduled out normally.
2570 for_each_sibling_event(event, group_event) {
2571 if (event == partial_group)
2574 event_sched_out(event, ctx);
2576 event_sched_out(group_event, ctx);
2579 pmu->cancel_txn(pmu);
2584 * Work out whether we can put this event group on the CPU now.
2586 static int group_can_go_on(struct perf_event *event, int can_add_hw)
2588 struct perf_event_pmu_context *epc = event->pmu_ctx;
2589 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context);
2592 * Groups consisting entirely of software events can always go on.
2594 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2597 * If an exclusive group is already on, no other hardware
2603 * If this group is exclusive and there are already
2604 * events on the CPU, it can't go on.
2606 if (event->attr.exclusive && !list_empty(get_event_list(event)))
2609 * Otherwise, try to add it if all previous groups were able
2615 static void add_event_to_ctx(struct perf_event *event,
2616 struct perf_event_context *ctx)
2618 list_add_event(event, ctx);
2619 perf_group_attach(event);
2622 static void task_ctx_sched_out(struct perf_event_context *ctx,
2623 enum event_type_t event_type)
2625 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2627 if (!cpuctx->task_ctx)
2630 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2633 ctx_sched_out(ctx, event_type);
2636 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2637 struct perf_event_context *ctx)
2639 ctx_sched_in(&cpuctx->ctx, EVENT_PINNED);
2641 ctx_sched_in(ctx, EVENT_PINNED);
2642 ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE);
2644 ctx_sched_in(ctx, EVENT_FLEXIBLE);
2648 * We want to maintain the following priority of scheduling:
2649 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2650 * - task pinned (EVENT_PINNED)
2651 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2652 * - task flexible (EVENT_FLEXIBLE).
2654 * In order to avoid unscheduling and scheduling back in everything every
2655 * time an event is added, only do it for the groups of equal priority and
2658 * This can be called after a batch operation on task events, in which case
2659 * event_type is a bit mask of the types of events involved. For CPU events,
2660 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2663 * XXX: ctx_resched() reschedule entire perf_event_context while adding new
2664 * event to the context or enabling existing event in the context. We can
2665 * probably optimize it by rescheduling only affected pmu_ctx.
2667 static void ctx_resched(struct perf_cpu_context *cpuctx,
2668 struct perf_event_context *task_ctx,
2669 enum event_type_t event_type)
2671 bool cpu_event = !!(event_type & EVENT_CPU);
2674 * If pinned groups are involved, flexible groups also need to be
2677 if (event_type & EVENT_PINNED)
2678 event_type |= EVENT_FLEXIBLE;
2680 event_type &= EVENT_ALL;
2682 perf_ctx_disable(&cpuctx->ctx);
2684 perf_ctx_disable(task_ctx);
2685 task_ctx_sched_out(task_ctx, event_type);
2689 * Decide which cpu ctx groups to schedule out based on the types
2690 * of events that caused rescheduling:
2691 * - EVENT_CPU: schedule out corresponding groups;
2692 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2693 * - otherwise, do nothing more.
2696 ctx_sched_out(&cpuctx->ctx, event_type);
2697 else if (event_type & EVENT_PINNED)
2698 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
2700 perf_event_sched_in(cpuctx, task_ctx);
2702 perf_ctx_enable(&cpuctx->ctx);
2704 perf_ctx_enable(task_ctx);
2707 void perf_pmu_resched(struct pmu *pmu)
2709 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2710 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2712 perf_ctx_lock(cpuctx, task_ctx);
2713 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2714 perf_ctx_unlock(cpuctx, task_ctx);
2718 * Cross CPU call to install and enable a performance event
2720 * Very similar to remote_function() + event_function() but cannot assume that
2721 * things like ctx->is_active and cpuctx->task_ctx are set.
2723 static int __perf_install_in_context(void *info)
2725 struct perf_event *event = info;
2726 struct perf_event_context *ctx = event->ctx;
2727 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
2728 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2729 bool reprogram = true;
2732 raw_spin_lock(&cpuctx->ctx.lock);
2734 raw_spin_lock(&ctx->lock);
2737 reprogram = (ctx->task == current);
2740 * If the task is running, it must be running on this CPU,
2741 * otherwise we cannot reprogram things.
2743 * If its not running, we don't care, ctx->lock will
2744 * serialize against it becoming runnable.
2746 if (task_curr(ctx->task) && !reprogram) {
2751 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2752 } else if (task_ctx) {
2753 raw_spin_lock(&task_ctx->lock);
2756 #ifdef CONFIG_CGROUP_PERF
2757 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2759 * If the current cgroup doesn't match the event's
2760 * cgroup, we should not try to schedule it.
2762 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2763 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2764 event->cgrp->css.cgroup);
2769 ctx_sched_out(ctx, EVENT_TIME);
2770 add_event_to_ctx(event, ctx);
2771 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2773 add_event_to_ctx(event, ctx);
2777 perf_ctx_unlock(cpuctx, task_ctx);
2782 static bool exclusive_event_installable(struct perf_event *event,
2783 struct perf_event_context *ctx);
2786 * Attach a performance event to a context.
2788 * Very similar to event_function_call, see comment there.
2791 perf_install_in_context(struct perf_event_context *ctx,
2792 struct perf_event *event,
2795 struct task_struct *task = READ_ONCE(ctx->task);
2797 lockdep_assert_held(&ctx->mutex);
2799 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2801 if (event->cpu != -1)
2802 WARN_ON_ONCE(event->cpu != cpu);
2805 * Ensures that if we can observe event->ctx, both the event and ctx
2806 * will be 'complete'. See perf_iterate_sb_cpu().
2808 smp_store_release(&event->ctx, ctx);
2811 * perf_event_attr::disabled events will not run and can be initialized
2812 * without IPI. Except when this is the first event for the context, in
2813 * that case we need the magic of the IPI to set ctx->is_active.
2815 * The IOC_ENABLE that is sure to follow the creation of a disabled
2816 * event will issue the IPI and reprogram the hardware.
2818 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF &&
2819 ctx->nr_events && !is_cgroup_event(event)) {
2820 raw_spin_lock_irq(&ctx->lock);
2821 if (ctx->task == TASK_TOMBSTONE) {
2822 raw_spin_unlock_irq(&ctx->lock);
2825 add_event_to_ctx(event, ctx);
2826 raw_spin_unlock_irq(&ctx->lock);
2831 cpu_function_call(cpu, __perf_install_in_context, event);
2836 * Should not happen, we validate the ctx is still alive before calling.
2838 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2842 * Installing events is tricky because we cannot rely on ctx->is_active
2843 * to be set in case this is the nr_events 0 -> 1 transition.
2845 * Instead we use task_curr(), which tells us if the task is running.
2846 * However, since we use task_curr() outside of rq::lock, we can race
2847 * against the actual state. This means the result can be wrong.
2849 * If we get a false positive, we retry, this is harmless.
2851 * If we get a false negative, things are complicated. If we are after
2852 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2853 * value must be correct. If we're before, it doesn't matter since
2854 * perf_event_context_sched_in() will program the counter.
2856 * However, this hinges on the remote context switch having observed
2857 * our task->perf_event_ctxp[] store, such that it will in fact take
2858 * ctx::lock in perf_event_context_sched_in().
2860 * We do this by task_function_call(), if the IPI fails to hit the task
2861 * we know any future context switch of task must see the
2862 * perf_event_ctpx[] store.
2866 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2867 * task_cpu() load, such that if the IPI then does not find the task
2868 * running, a future context switch of that task must observe the
2873 if (!task_function_call(task, __perf_install_in_context, event))
2876 raw_spin_lock_irq(&ctx->lock);
2878 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2880 * Cannot happen because we already checked above (which also
2881 * cannot happen), and we hold ctx->mutex, which serializes us
2882 * against perf_event_exit_task_context().
2884 raw_spin_unlock_irq(&ctx->lock);
2888 * If the task is not running, ctx->lock will avoid it becoming so,
2889 * thus we can safely install the event.
2891 if (task_curr(task)) {
2892 raw_spin_unlock_irq(&ctx->lock);
2895 add_event_to_ctx(event, ctx);
2896 raw_spin_unlock_irq(&ctx->lock);
2900 * Cross CPU call to enable a performance event
2902 static void __perf_event_enable(struct perf_event *event,
2903 struct perf_cpu_context *cpuctx,
2904 struct perf_event_context *ctx,
2907 struct perf_event *leader = event->group_leader;
2908 struct perf_event_context *task_ctx;
2910 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2911 event->state <= PERF_EVENT_STATE_ERROR)
2915 ctx_sched_out(ctx, EVENT_TIME);
2917 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2918 perf_cgroup_event_enable(event, ctx);
2920 if (!ctx->is_active)
2923 if (!event_filter_match(event)) {
2924 ctx_sched_in(ctx, EVENT_TIME);
2929 * If the event is in a group and isn't the group leader,
2930 * then don't put it on unless the group is on.
2932 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2933 ctx_sched_in(ctx, EVENT_TIME);
2937 task_ctx = cpuctx->task_ctx;
2939 WARN_ON_ONCE(task_ctx != ctx);
2941 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2947 * If event->ctx is a cloned context, callers must make sure that
2948 * every task struct that event->ctx->task could possibly point to
2949 * remains valid. This condition is satisfied when called through
2950 * perf_event_for_each_child or perf_event_for_each as described
2951 * for perf_event_disable.
2953 static void _perf_event_enable(struct perf_event *event)
2955 struct perf_event_context *ctx = event->ctx;
2957 raw_spin_lock_irq(&ctx->lock);
2958 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2959 event->state < PERF_EVENT_STATE_ERROR) {
2961 raw_spin_unlock_irq(&ctx->lock);
2966 * If the event is in error state, clear that first.
2968 * That way, if we see the event in error state below, we know that it
2969 * has gone back into error state, as distinct from the task having
2970 * been scheduled away before the cross-call arrived.
2972 if (event->state == PERF_EVENT_STATE_ERROR) {
2974 * Detached SIBLING events cannot leave ERROR state.
2976 if (event->event_caps & PERF_EV_CAP_SIBLING &&
2977 event->group_leader == event)
2980 event->state = PERF_EVENT_STATE_OFF;
2982 raw_spin_unlock_irq(&ctx->lock);
2984 event_function_call(event, __perf_event_enable, NULL);
2988 * See perf_event_disable();
2990 void perf_event_enable(struct perf_event *event)
2992 struct perf_event_context *ctx;
2994 ctx = perf_event_ctx_lock(event);
2995 _perf_event_enable(event);
2996 perf_event_ctx_unlock(event, ctx);
2998 EXPORT_SYMBOL_GPL(perf_event_enable);
3000 struct stop_event_data {
3001 struct perf_event *event;
3002 unsigned int restart;
3005 static int __perf_event_stop(void *info)
3007 struct stop_event_data *sd = info;
3008 struct perf_event *event = sd->event;
3010 /* if it's already INACTIVE, do nothing */
3011 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3014 /* matches smp_wmb() in event_sched_in() */
3018 * There is a window with interrupts enabled before we get here,
3019 * so we need to check again lest we try to stop another CPU's event.
3021 if (READ_ONCE(event->oncpu) != smp_processor_id())
3024 event->pmu->stop(event, PERF_EF_UPDATE);
3027 * May race with the actual stop (through perf_pmu_output_stop()),
3028 * but it is only used for events with AUX ring buffer, and such
3029 * events will refuse to restart because of rb::aux_mmap_count==0,
3030 * see comments in perf_aux_output_begin().
3032 * Since this is happening on an event-local CPU, no trace is lost
3036 event->pmu->start(event, 0);
3041 static int perf_event_stop(struct perf_event *event, int restart)
3043 struct stop_event_data sd = {
3050 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3053 /* matches smp_wmb() in event_sched_in() */
3057 * We only want to restart ACTIVE events, so if the event goes
3058 * inactive here (event->oncpu==-1), there's nothing more to do;
3059 * fall through with ret==-ENXIO.
3061 ret = cpu_function_call(READ_ONCE(event->oncpu),
3062 __perf_event_stop, &sd);
3063 } while (ret == -EAGAIN);
3069 * In order to contain the amount of racy and tricky in the address filter
3070 * configuration management, it is a two part process:
3072 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3073 * we update the addresses of corresponding vmas in
3074 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3075 * (p2) when an event is scheduled in (pmu::add), it calls
3076 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3077 * if the generation has changed since the previous call.
3079 * If (p1) happens while the event is active, we restart it to force (p2).
3081 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3082 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3084 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3085 * registered mapping, called for every new mmap(), with mm::mmap_lock down
3087 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3090 void perf_event_addr_filters_sync(struct perf_event *event)
3092 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3094 if (!has_addr_filter(event))
3097 raw_spin_lock(&ifh->lock);
3098 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3099 event->pmu->addr_filters_sync(event);
3100 event->hw.addr_filters_gen = event->addr_filters_gen;
3102 raw_spin_unlock(&ifh->lock);
3104 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3106 static int _perf_event_refresh(struct perf_event *event, int refresh)
3109 * not supported on inherited events
3111 if (event->attr.inherit || !is_sampling_event(event))
3114 atomic_add(refresh, &event->event_limit);
3115 _perf_event_enable(event);
3121 * See perf_event_disable()
3123 int perf_event_refresh(struct perf_event *event, int refresh)
3125 struct perf_event_context *ctx;
3128 ctx = perf_event_ctx_lock(event);
3129 ret = _perf_event_refresh(event, refresh);
3130 perf_event_ctx_unlock(event, ctx);
3134 EXPORT_SYMBOL_GPL(perf_event_refresh);
3136 static int perf_event_modify_breakpoint(struct perf_event *bp,
3137 struct perf_event_attr *attr)
3141 _perf_event_disable(bp);
3143 err = modify_user_hw_breakpoint_check(bp, attr, true);
3145 if (!bp->attr.disabled)
3146 _perf_event_enable(bp);
3152 * Copy event-type-independent attributes that may be modified.
3154 static void perf_event_modify_copy_attr(struct perf_event_attr *to,
3155 const struct perf_event_attr *from)
3157 to->sig_data = from->sig_data;
3160 static int perf_event_modify_attr(struct perf_event *event,
3161 struct perf_event_attr *attr)
3163 int (*func)(struct perf_event *, struct perf_event_attr *);
3164 struct perf_event *child;
3167 if (event->attr.type != attr->type)
3170 switch (event->attr.type) {
3171 case PERF_TYPE_BREAKPOINT:
3172 func = perf_event_modify_breakpoint;
3175 /* Place holder for future additions. */
3179 WARN_ON_ONCE(event->ctx->parent_ctx);
3181 mutex_lock(&event->child_mutex);
3183 * Event-type-independent attributes must be copied before event-type
3184 * modification, which will validate that final attributes match the
3185 * source attributes after all relevant attributes have been copied.
3187 perf_event_modify_copy_attr(&event->attr, attr);
3188 err = func(event, attr);
3191 list_for_each_entry(child, &event->child_list, child_list) {
3192 perf_event_modify_copy_attr(&child->attr, attr);
3193 err = func(child, attr);
3198 mutex_unlock(&event->child_mutex);
3202 static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx,
3203 enum event_type_t event_type)
3205 struct perf_event_context *ctx = pmu_ctx->ctx;
3206 struct perf_event *event, *tmp;
3207 struct pmu *pmu = pmu_ctx->pmu;
3209 if (ctx->task && !ctx->is_active) {
3210 struct perf_cpu_pmu_context *cpc;
3212 cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3213 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3214 cpc->task_epc = NULL;
3220 perf_pmu_disable(pmu);
3221 if (event_type & EVENT_PINNED) {
3222 list_for_each_entry_safe(event, tmp,
3223 &pmu_ctx->pinned_active,
3225 group_sched_out(event, ctx);
3228 if (event_type & EVENT_FLEXIBLE) {
3229 list_for_each_entry_safe(event, tmp,
3230 &pmu_ctx->flexible_active,
3232 group_sched_out(event, ctx);
3234 * Since we cleared EVENT_FLEXIBLE, also clear
3235 * rotate_necessary, is will be reset by
3236 * ctx_flexible_sched_in() when needed.
3238 pmu_ctx->rotate_necessary = 0;
3240 perf_pmu_enable(pmu);
3244 ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type)
3246 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3247 struct perf_event_pmu_context *pmu_ctx;
3248 int is_active = ctx->is_active;
3250 lockdep_assert_held(&ctx->lock);
3252 if (likely(!ctx->nr_events)) {
3254 * See __perf_remove_from_context().
3256 WARN_ON_ONCE(ctx->is_active);
3258 WARN_ON_ONCE(cpuctx->task_ctx);
3263 * Always update time if it was set; not only when it changes.
3264 * Otherwise we can 'forget' to update time for any but the last
3265 * context we sched out. For example:
3267 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3268 * ctx_sched_out(.event_type = EVENT_PINNED)
3270 * would only update time for the pinned events.
3272 if (is_active & EVENT_TIME) {
3273 /* update (and stop) ctx time */
3274 update_context_time(ctx);
3275 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx);
3277 * CPU-release for the below ->is_active store,
3278 * see __load_acquire() in perf_event_time_now()
3283 ctx->is_active &= ~event_type;
3284 if (!(ctx->is_active & EVENT_ALL))
3288 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3289 if (!ctx->is_active)
3290 cpuctx->task_ctx = NULL;
3293 is_active ^= ctx->is_active; /* changed bits */
3295 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry)
3296 __pmu_ctx_sched_out(pmu_ctx, is_active);
3300 * Test whether two contexts are equivalent, i.e. whether they have both been
3301 * cloned from the same version of the same context.
3303 * Equivalence is measured using a generation number in the context that is
3304 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3305 * and list_del_event().
3307 static int context_equiv(struct perf_event_context *ctx1,
3308 struct perf_event_context *ctx2)
3310 lockdep_assert_held(&ctx1->lock);
3311 lockdep_assert_held(&ctx2->lock);
3313 /* Pinning disables the swap optimization */
3314 if (ctx1->pin_count || ctx2->pin_count)
3317 /* If ctx1 is the parent of ctx2 */
3318 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3321 /* If ctx2 is the parent of ctx1 */
3322 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3326 * If ctx1 and ctx2 have the same parent; we flatten the parent
3327 * hierarchy, see perf_event_init_context().
3329 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3330 ctx1->parent_gen == ctx2->parent_gen)
3337 static void __perf_event_sync_stat(struct perf_event *event,
3338 struct perf_event *next_event)
3342 if (!event->attr.inherit_stat)
3346 * Update the event value, we cannot use perf_event_read()
3347 * because we're in the middle of a context switch and have IRQs
3348 * disabled, which upsets smp_call_function_single(), however
3349 * we know the event must be on the current CPU, therefore we
3350 * don't need to use it.
3352 if (event->state == PERF_EVENT_STATE_ACTIVE)
3353 event->pmu->read(event);
3355 perf_event_update_time(event);
3358 * In order to keep per-task stats reliable we need to flip the event
3359 * values when we flip the contexts.
3361 value = local64_read(&next_event->count);
3362 value = local64_xchg(&event->count, value);
3363 local64_set(&next_event->count, value);
3365 swap(event->total_time_enabled, next_event->total_time_enabled);
3366 swap(event->total_time_running, next_event->total_time_running);
3369 * Since we swizzled the values, update the user visible data too.
3371 perf_event_update_userpage(event);
3372 perf_event_update_userpage(next_event);
3375 static void perf_event_sync_stat(struct perf_event_context *ctx,
3376 struct perf_event_context *next_ctx)
3378 struct perf_event *event, *next_event;
3383 update_context_time(ctx);
3385 event = list_first_entry(&ctx->event_list,
3386 struct perf_event, event_entry);
3388 next_event = list_first_entry(&next_ctx->event_list,
3389 struct perf_event, event_entry);
3391 while (&event->event_entry != &ctx->event_list &&
3392 &next_event->event_entry != &next_ctx->event_list) {
3394 __perf_event_sync_stat(event, next_event);
3396 event = list_next_entry(event, event_entry);
3397 next_event = list_next_entry(next_event, event_entry);
3401 #define double_list_for_each_entry(pos1, pos2, head1, head2, member) \
3402 for (pos1 = list_first_entry(head1, typeof(*pos1), member), \
3403 pos2 = list_first_entry(head2, typeof(*pos2), member); \
3404 !list_entry_is_head(pos1, head1, member) && \
3405 !list_entry_is_head(pos2, head2, member); \
3406 pos1 = list_next_entry(pos1, member), \
3407 pos2 = list_next_entry(pos2, member))
3409 static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx,
3410 struct perf_event_context *next_ctx)
3412 struct perf_event_pmu_context *prev_epc, *next_epc;
3414 if (!prev_ctx->nr_task_data)
3417 double_list_for_each_entry(prev_epc, next_epc,
3418 &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list,
3421 if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu))
3425 * PMU specific parts of task perf context can require
3426 * additional synchronization. As an example of such
3427 * synchronization see implementation details of Intel
3428 * LBR call stack data profiling;
3430 if (prev_epc->pmu->swap_task_ctx)
3431 prev_epc->pmu->swap_task_ctx(prev_epc, next_epc);
3433 swap(prev_epc->task_ctx_data, next_epc->task_ctx_data);
3437 static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in)
3439 struct perf_event_pmu_context *pmu_ctx;
3440 struct perf_cpu_pmu_context *cpc;
3442 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3443 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3445 if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task)
3446 pmu_ctx->pmu->sched_task(pmu_ctx, sched_in);
3451 perf_event_context_sched_out(struct task_struct *task, struct task_struct *next)
3453 struct perf_event_context *ctx = task->perf_event_ctxp;
3454 struct perf_event_context *next_ctx;
3455 struct perf_event_context *parent, *next_parent;
3462 next_ctx = rcu_dereference(next->perf_event_ctxp);
3466 parent = rcu_dereference(ctx->parent_ctx);
3467 next_parent = rcu_dereference(next_ctx->parent_ctx);
3469 /* If neither context have a parent context; they cannot be clones. */
3470 if (!parent && !next_parent)
3473 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3475 * Looks like the two contexts are clones, so we might be
3476 * able to optimize the context switch. We lock both
3477 * contexts and check that they are clones under the
3478 * lock (including re-checking that neither has been
3479 * uncloned in the meantime). It doesn't matter which
3480 * order we take the locks because no other cpu could
3481 * be trying to lock both of these tasks.
3483 raw_spin_lock(&ctx->lock);
3484 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3485 if (context_equiv(ctx, next_ctx)) {
3487 perf_ctx_disable(ctx);
3489 /* PMIs are disabled; ctx->nr_pending is stable. */
3490 if (local_read(&ctx->nr_pending) ||
3491 local_read(&next_ctx->nr_pending)) {
3493 * Must not swap out ctx when there's pending
3494 * events that rely on the ctx->task relation.
3496 raw_spin_unlock(&next_ctx->lock);
3501 WRITE_ONCE(ctx->task, next);
3502 WRITE_ONCE(next_ctx->task, task);
3504 perf_ctx_sched_task_cb(ctx, false);
3505 perf_event_swap_task_ctx_data(ctx, next_ctx);
3507 perf_ctx_enable(ctx);
3510 * RCU_INIT_POINTER here is safe because we've not
3511 * modified the ctx and the above modification of
3512 * ctx->task and ctx->task_ctx_data are immaterial
3513 * since those values are always verified under
3514 * ctx->lock which we're now holding.
3516 RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx);
3517 RCU_INIT_POINTER(next->perf_event_ctxp, ctx);
3521 perf_event_sync_stat(ctx, next_ctx);
3523 raw_spin_unlock(&next_ctx->lock);
3524 raw_spin_unlock(&ctx->lock);
3530 raw_spin_lock(&ctx->lock);
3531 perf_ctx_disable(ctx);
3534 perf_ctx_sched_task_cb(ctx, false);
3535 task_ctx_sched_out(ctx, EVENT_ALL);
3537 perf_ctx_enable(ctx);
3538 raw_spin_unlock(&ctx->lock);
3542 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3543 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
3545 void perf_sched_cb_dec(struct pmu *pmu)
3547 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3549 this_cpu_dec(perf_sched_cb_usages);
3552 if (!--cpc->sched_cb_usage)
3553 list_del(&cpc->sched_cb_entry);
3557 void perf_sched_cb_inc(struct pmu *pmu)
3559 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context);
3561 if (!cpc->sched_cb_usage++)
3562 list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3565 this_cpu_inc(perf_sched_cb_usages);
3569 * This function provides the context switch callback to the lower code
3570 * layer. It is invoked ONLY when the context switch callback is enabled.
3572 * This callback is relevant even to per-cpu events; for example multi event
3573 * PEBS requires this to provide PID/TID information. This requires we flush
3574 * all queued PEBS records before we context switch to a new task.
3576 static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in)
3578 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3583 /* software PMUs will not have sched_task */
3584 if (WARN_ON_ONCE(!pmu->sched_task))
3587 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3588 perf_pmu_disable(pmu);
3590 pmu->sched_task(cpc->task_epc, sched_in);
3592 perf_pmu_enable(pmu);
3593 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3596 static void perf_pmu_sched_task(struct task_struct *prev,
3597 struct task_struct *next,
3600 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3601 struct perf_cpu_pmu_context *cpc;
3603 /* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */
3604 if (prev == next || cpuctx->task_ctx)
3607 list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry)
3608 __perf_pmu_sched_task(cpc, sched_in);
3611 static void perf_event_switch(struct task_struct *task,
3612 struct task_struct *next_prev, bool sched_in);
3615 * Called from scheduler to remove the events of the current task,
3616 * with interrupts disabled.
3618 * We stop each event and update the event value in event->count.
3620 * This does not protect us against NMI, but disable()
3621 * sets the disabled bit in the control field of event _before_
3622 * accessing the event control register. If a NMI hits, then it will
3623 * not restart the event.
3625 void __perf_event_task_sched_out(struct task_struct *task,
3626 struct task_struct *next)
3628 if (__this_cpu_read(perf_sched_cb_usages))
3629 perf_pmu_sched_task(task, next, false);
3631 if (atomic_read(&nr_switch_events))
3632 perf_event_switch(task, next, false);
3634 perf_event_context_sched_out(task, next);
3637 * if cgroup events exist on this CPU, then we need
3638 * to check if we have to switch out PMU state.
3639 * cgroup event are system-wide mode only
3641 perf_cgroup_switch(next);
3644 static bool perf_less_group_idx(const void *l, const void *r)
3646 const struct perf_event *le = *(const struct perf_event **)l;
3647 const struct perf_event *re = *(const struct perf_event **)r;
3649 return le->group_index < re->group_index;
3652 static void swap_ptr(void *l, void *r)
3654 void **lp = l, **rp = r;
3659 static const struct min_heap_callbacks perf_min_heap = {
3660 .elem_size = sizeof(struct perf_event *),
3661 .less = perf_less_group_idx,
3665 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3667 struct perf_event **itrs = heap->data;
3670 itrs[heap->nr] = event;
3675 static void __link_epc(struct perf_event_pmu_context *pmu_ctx)
3677 struct perf_cpu_pmu_context *cpc;
3679 if (!pmu_ctx->ctx->task)
3682 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
3683 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
3684 cpc->task_epc = pmu_ctx;
3687 static noinline int visit_groups_merge(struct perf_event_context *ctx,
3688 struct perf_event_groups *groups, int cpu,
3690 int (*func)(struct perf_event *, void *),
3693 #ifdef CONFIG_CGROUP_PERF
3694 struct cgroup_subsys_state *css = NULL;
3696 struct perf_cpu_context *cpuctx = NULL;
3697 /* Space for per CPU and/or any CPU event iterators. */
3698 struct perf_event *itrs[2];
3699 struct min_heap event_heap;
3700 struct perf_event **evt;
3703 if (pmu->filter && pmu->filter(pmu, cpu))
3707 cpuctx = this_cpu_ptr(&perf_cpu_context);
3708 event_heap = (struct min_heap){
3709 .data = cpuctx->heap,
3711 .size = cpuctx->heap_size,
3714 lockdep_assert_held(&cpuctx->ctx.lock);
3716 #ifdef CONFIG_CGROUP_PERF
3718 css = &cpuctx->cgrp->css;
3721 event_heap = (struct min_heap){
3724 .size = ARRAY_SIZE(itrs),
3726 /* Events not within a CPU context may be on any CPU. */
3727 __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL));
3729 evt = event_heap.data;
3731 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL));
3733 #ifdef CONFIG_CGROUP_PERF
3734 for (; css; css = css->parent)
3735 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup));
3738 if (event_heap.nr) {
3739 __link_epc((*evt)->pmu_ctx);
3740 perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu);
3743 min_heapify_all(&event_heap, &perf_min_heap);
3745 while (event_heap.nr) {
3746 ret = func(*evt, data);
3750 *evt = perf_event_groups_next(*evt, pmu);
3752 min_heapify(&event_heap, 0, &perf_min_heap);
3754 min_heap_pop(&event_heap, &perf_min_heap);
3761 * Because the userpage is strictly per-event (there is no concept of context,
3762 * so there cannot be a context indirection), every userpage must be updated
3763 * when context time starts :-(
3765 * IOW, we must not miss EVENT_TIME edges.
3767 static inline bool event_update_userpage(struct perf_event *event)
3769 if (likely(!atomic_read(&event->mmap_count)))
3772 perf_event_update_time(event);
3773 perf_event_update_userpage(event);
3778 static inline void group_update_userpage(struct perf_event *group_event)
3780 struct perf_event *event;
3782 if (!event_update_userpage(group_event))
3785 for_each_sibling_event(event, group_event)
3786 event_update_userpage(event);
3789 static int merge_sched_in(struct perf_event *event, void *data)
3791 struct perf_event_context *ctx = event->ctx;
3792 int *can_add_hw = data;
3794 if (event->state <= PERF_EVENT_STATE_OFF)
3797 if (!event_filter_match(event))
3800 if (group_can_go_on(event, *can_add_hw)) {
3801 if (!group_sched_in(event, ctx))
3802 list_add_tail(&event->active_list, get_event_list(event));
3805 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3807 if (event->attr.pinned) {
3808 perf_cgroup_event_disable(event, ctx);
3809 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3811 struct perf_cpu_pmu_context *cpc;
3813 event->pmu_ctx->rotate_necessary = 1;
3814 cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context);
3815 perf_mux_hrtimer_restart(cpc);
3816 group_update_userpage(event);
3823 static void ctx_pinned_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3825 struct perf_event_pmu_context *pmu_ctx;
3829 visit_groups_merge(ctx, &ctx->pinned_groups,
3830 smp_processor_id(), pmu,
3831 merge_sched_in, &can_add_hw);
3833 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3835 visit_groups_merge(ctx, &ctx->pinned_groups,
3836 smp_processor_id(), pmu_ctx->pmu,
3837 merge_sched_in, &can_add_hw);
3842 static void ctx_flexible_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3844 struct perf_event_pmu_context *pmu_ctx;
3848 visit_groups_merge(ctx, &ctx->flexible_groups,
3849 smp_processor_id(), pmu,
3850 merge_sched_in, &can_add_hw);
3852 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) {
3854 visit_groups_merge(ctx, &ctx->flexible_groups,
3855 smp_processor_id(), pmu_ctx->pmu,
3856 merge_sched_in, &can_add_hw);
3861 static void __pmu_ctx_sched_in(struct perf_event_context *ctx, struct pmu *pmu)
3863 ctx_flexible_sched_in(ctx, pmu);
3867 ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type)
3869 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3870 int is_active = ctx->is_active;
3872 lockdep_assert_held(&ctx->lock);
3874 if (likely(!ctx->nr_events))
3877 if (!(is_active & EVENT_TIME)) {
3878 /* start ctx time */
3879 __update_context_time(ctx, false);
3880 perf_cgroup_set_timestamp(cpuctx);
3882 * CPU-release for the below ->is_active store,
3883 * see __load_acquire() in perf_event_time_now()
3888 ctx->is_active |= (event_type | EVENT_TIME);
3891 cpuctx->task_ctx = ctx;
3893 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3896 is_active ^= ctx->is_active; /* changed bits */
3899 * First go through the list and put on any pinned groups
3900 * in order to give them the best chance of going on.
3902 if (is_active & EVENT_PINNED)
3903 ctx_pinned_sched_in(ctx, NULL);
3905 /* Then walk through the lower prio flexible groups */
3906 if (is_active & EVENT_FLEXIBLE)
3907 ctx_flexible_sched_in(ctx, NULL);
3910 static void perf_event_context_sched_in(struct task_struct *task)
3912 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
3913 struct perf_event_context *ctx;
3916 ctx = rcu_dereference(task->perf_event_ctxp);
3920 if (cpuctx->task_ctx == ctx) {
3921 perf_ctx_lock(cpuctx, ctx);
3922 perf_ctx_disable(ctx);
3924 perf_ctx_sched_task_cb(ctx, true);
3926 perf_ctx_enable(ctx);
3927 perf_ctx_unlock(cpuctx, ctx);
3931 perf_ctx_lock(cpuctx, ctx);
3933 * We must check ctx->nr_events while holding ctx->lock, such
3934 * that we serialize against perf_install_in_context().
3936 if (!ctx->nr_events)
3939 perf_ctx_disable(ctx);
3941 * We want to keep the following priority order:
3942 * cpu pinned (that don't need to move), task pinned,
3943 * cpu flexible, task flexible.
3945 * However, if task's ctx is not carrying any pinned
3946 * events, no need to flip the cpuctx's events around.
3948 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) {
3949 perf_ctx_disable(&cpuctx->ctx);
3950 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE);
3953 perf_event_sched_in(cpuctx, ctx);
3955 perf_ctx_sched_task_cb(cpuctx->task_ctx, true);
3957 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3958 perf_ctx_enable(&cpuctx->ctx);
3960 perf_ctx_enable(ctx);
3963 perf_ctx_unlock(cpuctx, ctx);
3969 * Called from scheduler to add the events of the current task
3970 * with interrupts disabled.
3972 * We restore the event value and then enable it.
3974 * This does not protect us against NMI, but enable()
3975 * sets the enabled bit in the control field of event _before_
3976 * accessing the event control register. If a NMI hits, then it will
3977 * keep the event running.
3979 void __perf_event_task_sched_in(struct task_struct *prev,
3980 struct task_struct *task)
3982 perf_event_context_sched_in(task);
3984 if (atomic_read(&nr_switch_events))
3985 perf_event_switch(task, prev, true);
3987 if (__this_cpu_read(perf_sched_cb_usages))
3988 perf_pmu_sched_task(prev, task, true);
3991 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3993 u64 frequency = event->attr.sample_freq;
3994 u64 sec = NSEC_PER_SEC;
3995 u64 divisor, dividend;
3997 int count_fls, nsec_fls, frequency_fls, sec_fls;
3999 count_fls = fls64(count);
4000 nsec_fls = fls64(nsec);
4001 frequency_fls = fls64(frequency);
4005 * We got @count in @nsec, with a target of sample_freq HZ
4006 * the target period becomes:
4009 * period = -------------------
4010 * @nsec * sample_freq
4015 * Reduce accuracy by one bit such that @a and @b converge
4016 * to a similar magnitude.
4018 #define REDUCE_FLS(a, b) \
4020 if (a##_fls > b##_fls) { \
4030 * Reduce accuracy until either term fits in a u64, then proceed with
4031 * the other, so that finally we can do a u64/u64 division.
4033 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
4034 REDUCE_FLS(nsec, frequency);
4035 REDUCE_FLS(sec, count);
4038 if (count_fls + sec_fls > 64) {
4039 divisor = nsec * frequency;
4041 while (count_fls + sec_fls > 64) {
4042 REDUCE_FLS(count, sec);
4046 dividend = count * sec;
4048 dividend = count * sec;
4050 while (nsec_fls + frequency_fls > 64) {
4051 REDUCE_FLS(nsec, frequency);
4055 divisor = nsec * frequency;
4061 return div64_u64(dividend, divisor);
4064 static DEFINE_PER_CPU(int, perf_throttled_count);
4065 static DEFINE_PER_CPU(u64, perf_throttled_seq);
4067 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
4069 struct hw_perf_event *hwc = &event->hw;
4070 s64 period, sample_period;
4073 period = perf_calculate_period(event, nsec, count);
4075 delta = (s64)(period - hwc->sample_period);
4076 delta = (delta + 7) / 8; /* low pass filter */
4078 sample_period = hwc->sample_period + delta;
4083 hwc->sample_period = sample_period;
4085 if (local64_read(&hwc->period_left) > 8*sample_period) {
4087 event->pmu->stop(event, PERF_EF_UPDATE);
4089 local64_set(&hwc->period_left, 0);
4092 event->pmu->start(event, PERF_EF_RELOAD);
4097 * combine freq adjustment with unthrottling to avoid two passes over the
4098 * events. At the same time, make sure, having freq events does not change
4099 * the rate of unthrottling as that would introduce bias.
4102 perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle)
4104 struct perf_event *event;
4105 struct hw_perf_event *hwc;
4106 u64 now, period = TICK_NSEC;
4110 * only need to iterate over all events iff:
4111 * - context have events in frequency mode (needs freq adjust)
4112 * - there are events to unthrottle on this cpu
4114 if (!(ctx->nr_freq || unthrottle))
4117 raw_spin_lock(&ctx->lock);
4119 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4120 if (event->state != PERF_EVENT_STATE_ACTIVE)
4123 // XXX use visit thingy to avoid the -1,cpu match
4124 if (!event_filter_match(event))
4127 perf_pmu_disable(event->pmu);
4131 if (hwc->interrupts == MAX_INTERRUPTS) {
4132 hwc->interrupts = 0;
4133 perf_log_throttle(event, 1);
4134 event->pmu->start(event, 0);
4137 if (!event->attr.freq || !event->attr.sample_freq)
4141 * stop the event and update event->count
4143 event->pmu->stop(event, PERF_EF_UPDATE);
4145 now = local64_read(&event->count);
4146 delta = now - hwc->freq_count_stamp;
4147 hwc->freq_count_stamp = now;
4151 * reload only if value has changed
4152 * we have stopped the event so tell that
4153 * to perf_adjust_period() to avoid stopping it
4157 perf_adjust_period(event, period, delta, false);
4159 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4161 perf_pmu_enable(event->pmu);
4164 raw_spin_unlock(&ctx->lock);
4168 * Move @event to the tail of the @ctx's elegible events.
4170 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4173 * Rotate the first entry last of non-pinned groups. Rotation might be
4174 * disabled by the inheritance code.
4176 if (ctx->rotate_disable)
4179 perf_event_groups_delete(&ctx->flexible_groups, event);
4180 perf_event_groups_insert(&ctx->flexible_groups, event);
4183 /* pick an event from the flexible_groups to rotate */
4184 static inline struct perf_event *
4185 ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx)
4187 struct perf_event *event;
4188 struct rb_node *node;
4189 struct rb_root *tree;
4190 struct __group_key key = {
4191 .pmu = pmu_ctx->pmu,
4194 /* pick the first active flexible event */
4195 event = list_first_entry_or_null(&pmu_ctx->flexible_active,
4196 struct perf_event, active_list);
4200 /* if no active flexible event, pick the first event */
4201 tree = &pmu_ctx->ctx->flexible_groups.tree;
4203 if (!pmu_ctx->ctx->task) {
4204 key.cpu = smp_processor_id();
4206 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4208 event = __node_2_pe(node);
4213 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4215 event = __node_2_pe(node);
4219 key.cpu = smp_processor_id();
4220 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup);
4222 event = __node_2_pe(node);
4226 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4227 * finds there are unschedulable events, it will set it again.
4229 pmu_ctx->rotate_necessary = 0;
4234 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc)
4236 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4237 struct perf_event_pmu_context *cpu_epc, *task_epc = NULL;
4238 struct perf_event *cpu_event = NULL, *task_event = NULL;
4239 int cpu_rotate, task_rotate;
4243 * Since we run this from IRQ context, nobody can install new
4244 * events, thus the event count values are stable.
4247 cpu_epc = &cpc->epc;
4249 task_epc = cpc->task_epc;
4251 cpu_rotate = cpu_epc->rotate_necessary;
4252 task_rotate = task_epc ? task_epc->rotate_necessary : 0;
4254 if (!(cpu_rotate || task_rotate))
4257 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4258 perf_pmu_disable(pmu);
4261 task_event = ctx_event_to_rotate(task_epc);
4263 cpu_event = ctx_event_to_rotate(cpu_epc);
4266 * As per the order given at ctx_resched() first 'pop' task flexible
4267 * and then, if needed CPU flexible.
4269 if (task_event || (task_epc && cpu_event)) {
4270 update_context_time(task_epc->ctx);
4271 __pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE);
4275 update_context_time(&cpuctx->ctx);
4276 __pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE);
4277 rotate_ctx(&cpuctx->ctx, cpu_event);
4278 __pmu_ctx_sched_in(&cpuctx->ctx, pmu);
4282 rotate_ctx(task_epc->ctx, task_event);
4284 if (task_event || (task_epc && cpu_event))
4285 __pmu_ctx_sched_in(task_epc->ctx, pmu);
4287 perf_pmu_enable(pmu);
4288 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4293 void perf_event_task_tick(void)
4295 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4296 struct perf_event_context *ctx;
4299 lockdep_assert_irqs_disabled();
4301 __this_cpu_inc(perf_throttled_seq);
4302 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4303 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4305 perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled);
4308 ctx = rcu_dereference(current->perf_event_ctxp);
4310 perf_adjust_freq_unthr_context(ctx, !!throttled);
4314 static int event_enable_on_exec(struct perf_event *event,
4315 struct perf_event_context *ctx)
4317 if (!event->attr.enable_on_exec)
4320 event->attr.enable_on_exec = 0;
4321 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4324 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4330 * Enable all of a task's events that have been marked enable-on-exec.
4331 * This expects task == current.
4333 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
4335 struct perf_event_context *clone_ctx = NULL;
4336 enum event_type_t event_type = 0;
4337 struct perf_cpu_context *cpuctx;
4338 struct perf_event *event;
4339 unsigned long flags;
4342 local_irq_save(flags);
4343 if (WARN_ON_ONCE(current->perf_event_ctxp != ctx))
4346 if (!ctx->nr_events)
4349 cpuctx = this_cpu_ptr(&perf_cpu_context);
4350 perf_ctx_lock(cpuctx, ctx);
4351 ctx_sched_out(ctx, EVENT_TIME);
4353 list_for_each_entry(event, &ctx->event_list, event_entry) {
4354 enabled |= event_enable_on_exec(event, ctx);
4355 event_type |= get_event_type(event);
4359 * Unclone and reschedule this context if we enabled any event.
4362 clone_ctx = unclone_ctx(ctx);
4363 ctx_resched(cpuctx, ctx, event_type);
4365 ctx_sched_in(ctx, EVENT_TIME);
4367 perf_ctx_unlock(cpuctx, ctx);
4370 local_irq_restore(flags);
4376 static void perf_remove_from_owner(struct perf_event *event);
4377 static void perf_event_exit_event(struct perf_event *event,
4378 struct perf_event_context *ctx);
4381 * Removes all events from the current task that have been marked
4382 * remove-on-exec, and feeds their values back to parent events.
4384 static void perf_event_remove_on_exec(struct perf_event_context *ctx)
4386 struct perf_event_context *clone_ctx = NULL;
4387 struct perf_event *event, *next;
4388 unsigned long flags;
4389 bool modified = false;
4391 mutex_lock(&ctx->mutex);
4393 if (WARN_ON_ONCE(ctx->task != current))
4396 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) {
4397 if (!event->attr.remove_on_exec)
4400 if (!is_kernel_event(event))
4401 perf_remove_from_owner(event);
4405 perf_event_exit_event(event, ctx);
4408 raw_spin_lock_irqsave(&ctx->lock, flags);
4410 clone_ctx = unclone_ctx(ctx);
4411 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4414 mutex_unlock(&ctx->mutex);
4420 struct perf_read_data {
4421 struct perf_event *event;
4426 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4428 u16 local_pkg, event_pkg;
4430 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4431 int local_cpu = smp_processor_id();
4433 event_pkg = topology_physical_package_id(event_cpu);
4434 local_pkg = topology_physical_package_id(local_cpu);
4436 if (event_pkg == local_pkg)
4444 * Cross CPU call to read the hardware event
4446 static void __perf_event_read(void *info)
4448 struct perf_read_data *data = info;
4449 struct perf_event *sub, *event = data->event;
4450 struct perf_event_context *ctx = event->ctx;
4451 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
4452 struct pmu *pmu = event->pmu;
4455 * If this is a task context, we need to check whether it is
4456 * the current task context of this cpu. If not it has been
4457 * scheduled out before the smp call arrived. In that case
4458 * event->count would have been updated to a recent sample
4459 * when the event was scheduled out.
4461 if (ctx->task && cpuctx->task_ctx != ctx)
4464 raw_spin_lock(&ctx->lock);
4465 if (ctx->is_active & EVENT_TIME) {
4466 update_context_time(ctx);
4467 update_cgrp_time_from_event(event);
4470 perf_event_update_time(event);
4472 perf_event_update_sibling_time(event);
4474 if (event->state != PERF_EVENT_STATE_ACTIVE)
4483 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4487 for_each_sibling_event(sub, event) {
4488 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4490 * Use sibling's PMU rather than @event's since
4491 * sibling could be on different (eg: software) PMU.
4493 sub->pmu->read(sub);
4497 data->ret = pmu->commit_txn(pmu);
4500 raw_spin_unlock(&ctx->lock);
4503 static inline u64 perf_event_count(struct perf_event *event)
4505 return local64_read(&event->count) + atomic64_read(&event->child_count);
4508 static void calc_timer_values(struct perf_event *event,
4515 *now = perf_clock();
4516 ctx_time = perf_event_time_now(event, *now);
4517 __perf_update_times(event, ctx_time, enabled, running);
4521 * NMI-safe method to read a local event, that is an event that
4523 * - either for the current task, or for this CPU
4524 * - does not have inherit set, for inherited task events
4525 * will not be local and we cannot read them atomically
4526 * - must not have a pmu::count method
4528 int perf_event_read_local(struct perf_event *event, u64 *value,
4529 u64 *enabled, u64 *running)
4531 unsigned long flags;
4535 * Disabling interrupts avoids all counter scheduling (context
4536 * switches, timer based rotation and IPIs).
4538 local_irq_save(flags);
4541 * It must not be an event with inherit set, we cannot read
4542 * all child counters from atomic context.
4544 if (event->attr.inherit) {
4549 /* If this is a per-task event, it must be for current */
4550 if ((event->attach_state & PERF_ATTACH_TASK) &&
4551 event->hw.target != current) {
4556 /* If this is a per-CPU event, it must be for this CPU */
4557 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4558 event->cpu != smp_processor_id()) {
4563 /* If this is a pinned event it must be running on this CPU */
4564 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4570 * If the event is currently on this CPU, its either a per-task event,
4571 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4574 if (event->oncpu == smp_processor_id())
4575 event->pmu->read(event);
4577 *value = local64_read(&event->count);
4578 if (enabled || running) {
4579 u64 __enabled, __running, __now;
4581 calc_timer_values(event, &__now, &__enabled, &__running);
4583 *enabled = __enabled;
4585 *running = __running;
4588 local_irq_restore(flags);
4593 static int perf_event_read(struct perf_event *event, bool group)
4595 enum perf_event_state state = READ_ONCE(event->state);
4596 int event_cpu, ret = 0;
4599 * If event is enabled and currently active on a CPU, update the
4600 * value in the event structure:
4603 if (state == PERF_EVENT_STATE_ACTIVE) {
4604 struct perf_read_data data;
4607 * Orders the ->state and ->oncpu loads such that if we see
4608 * ACTIVE we must also see the right ->oncpu.
4610 * Matches the smp_wmb() from event_sched_in().
4614 event_cpu = READ_ONCE(event->oncpu);
4615 if ((unsigned)event_cpu >= nr_cpu_ids)
4618 data = (struct perf_read_data){
4625 event_cpu = __perf_event_read_cpu(event, event_cpu);
4628 * Purposely ignore the smp_call_function_single() return
4631 * If event_cpu isn't a valid CPU it means the event got
4632 * scheduled out and that will have updated the event count.
4634 * Therefore, either way, we'll have an up-to-date event count
4637 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4641 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4642 struct perf_event_context *ctx = event->ctx;
4643 unsigned long flags;
4645 raw_spin_lock_irqsave(&ctx->lock, flags);
4646 state = event->state;
4647 if (state != PERF_EVENT_STATE_INACTIVE) {
4648 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4653 * May read while context is not active (e.g., thread is
4654 * blocked), in that case we cannot update context time
4656 if (ctx->is_active & EVENT_TIME) {
4657 update_context_time(ctx);
4658 update_cgrp_time_from_event(event);
4661 perf_event_update_time(event);
4663 perf_event_update_sibling_time(event);
4664 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4671 * Initialize the perf_event context in a task_struct:
4673 static void __perf_event_init_context(struct perf_event_context *ctx)
4675 raw_spin_lock_init(&ctx->lock);
4676 mutex_init(&ctx->mutex);
4677 INIT_LIST_HEAD(&ctx->pmu_ctx_list);
4678 perf_event_groups_init(&ctx->pinned_groups);
4679 perf_event_groups_init(&ctx->flexible_groups);
4680 INIT_LIST_HEAD(&ctx->event_list);
4681 refcount_set(&ctx->refcount, 1);
4685 __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu)
4688 INIT_LIST_HEAD(&epc->pmu_ctx_entry);
4689 INIT_LIST_HEAD(&epc->pinned_active);
4690 INIT_LIST_HEAD(&epc->flexible_active);
4691 atomic_set(&epc->refcount, 1);
4694 static struct perf_event_context *
4695 alloc_perf_context(struct task_struct *task)
4697 struct perf_event_context *ctx;
4699 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4703 __perf_event_init_context(ctx);
4705 ctx->task = get_task_struct(task);
4710 static struct task_struct *
4711 find_lively_task_by_vpid(pid_t vpid)
4713 struct task_struct *task;
4719 task = find_task_by_vpid(vpid);
4721 get_task_struct(task);
4725 return ERR_PTR(-ESRCH);
4731 * Returns a matching context with refcount and pincount.
4733 static struct perf_event_context *
4734 find_get_context(struct task_struct *task, struct perf_event *event)
4736 struct perf_event_context *ctx, *clone_ctx = NULL;
4737 struct perf_cpu_context *cpuctx;
4738 unsigned long flags;
4742 /* Must be root to operate on a CPU event: */
4743 err = perf_allow_cpu(&event->attr);
4745 return ERR_PTR(err);
4747 cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
4750 raw_spin_lock_irqsave(&ctx->lock, flags);
4752 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4759 ctx = perf_lock_task_context(task, &flags);
4761 clone_ctx = unclone_ctx(ctx);
4764 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4769 ctx = alloc_perf_context(task);
4775 mutex_lock(&task->perf_event_mutex);
4777 * If it has already passed perf_event_exit_task().
4778 * we must see PF_EXITING, it takes this mutex too.
4780 if (task->flags & PF_EXITING)
4782 else if (task->perf_event_ctxp)
4787 rcu_assign_pointer(task->perf_event_ctxp, ctx);
4789 mutex_unlock(&task->perf_event_mutex);
4791 if (unlikely(err)) {
4803 return ERR_PTR(err);
4806 static struct perf_event_pmu_context *
4807 find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx,
4808 struct perf_event *event)
4810 struct perf_event_pmu_context *new = NULL, *epc;
4811 void *task_ctx_data = NULL;
4814 struct perf_cpu_pmu_context *cpc;
4816 cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu);
4818 raw_spin_lock_irq(&ctx->lock);
4820 atomic_set(&epc->refcount, 1);
4822 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4825 WARN_ON_ONCE(epc->ctx != ctx);
4826 atomic_inc(&epc->refcount);
4828 raw_spin_unlock_irq(&ctx->lock);
4832 new = kzalloc(sizeof(*epc), GFP_KERNEL);
4834 return ERR_PTR(-ENOMEM);
4836 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4837 task_ctx_data = alloc_task_ctx_data(pmu);
4838 if (!task_ctx_data) {
4840 return ERR_PTR(-ENOMEM);
4844 __perf_init_event_pmu_context(new, pmu);
4849 * lockdep_assert_held(&ctx->mutex);
4851 * can't because perf_event_init_task() doesn't actually hold the
4855 raw_spin_lock_irq(&ctx->lock);
4856 list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) {
4857 if (epc->pmu == pmu) {
4858 WARN_ON_ONCE(epc->ctx != ctx);
4859 atomic_inc(&epc->refcount);
4867 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list);
4871 if (task_ctx_data && !epc->task_ctx_data) {
4872 epc->task_ctx_data = task_ctx_data;
4873 task_ctx_data = NULL;
4874 ctx->nr_task_data++;
4876 raw_spin_unlock_irq(&ctx->lock);
4878 free_task_ctx_data(pmu, task_ctx_data);
4884 static void get_pmu_ctx(struct perf_event_pmu_context *epc)
4886 WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount));
4889 static void free_epc_rcu(struct rcu_head *head)
4891 struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head);
4893 kfree(epc->task_ctx_data);
4897 static void put_pmu_ctx(struct perf_event_pmu_context *epc)
4899 struct perf_event_context *ctx = epc->ctx;
4900 unsigned long flags;
4905 * lockdep_assert_held(&ctx->mutex);
4907 * can't because of the call-site in _free_event()/put_event()
4908 * which isn't always called under ctx->mutex.
4910 if (!atomic_dec_and_raw_lock_irqsave(&epc->refcount, &ctx->lock, flags))
4913 WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry));
4915 list_del_init(&epc->pmu_ctx_entry);
4918 WARN_ON_ONCE(!list_empty(&epc->pinned_active));
4919 WARN_ON_ONCE(!list_empty(&epc->flexible_active));
4921 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4926 call_rcu(&epc->rcu_head, free_epc_rcu);
4929 static void perf_event_free_filter(struct perf_event *event);
4931 static void free_event_rcu(struct rcu_head *head)
4933 struct perf_event *event = container_of(head, typeof(*event), rcu_head);
4936 put_pid_ns(event->ns);
4937 perf_event_free_filter(event);
4938 kmem_cache_free(perf_event_cache, event);
4941 static void ring_buffer_attach(struct perf_event *event,
4942 struct perf_buffer *rb);
4944 static void detach_sb_event(struct perf_event *event)
4946 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4948 raw_spin_lock(&pel->lock);
4949 list_del_rcu(&event->sb_list);
4950 raw_spin_unlock(&pel->lock);
4953 static bool is_sb_event(struct perf_event *event)
4955 struct perf_event_attr *attr = &event->attr;
4960 if (event->attach_state & PERF_ATTACH_TASK)
4963 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4964 attr->comm || attr->comm_exec ||
4965 attr->task || attr->ksymbol ||
4966 attr->context_switch || attr->text_poke ||
4972 static void unaccount_pmu_sb_event(struct perf_event *event)
4974 if (is_sb_event(event))
4975 detach_sb_event(event);
4978 #ifdef CONFIG_NO_HZ_FULL
4979 static DEFINE_SPINLOCK(nr_freq_lock);
4982 static void unaccount_freq_event_nohz(void)
4984 #ifdef CONFIG_NO_HZ_FULL
4985 spin_lock(&nr_freq_lock);
4986 if (atomic_dec_and_test(&nr_freq_events))
4987 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4988 spin_unlock(&nr_freq_lock);
4992 static void unaccount_freq_event(void)
4994 if (tick_nohz_full_enabled())
4995 unaccount_freq_event_nohz();
4997 atomic_dec(&nr_freq_events);
5000 static void unaccount_event(struct perf_event *event)
5007 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
5009 if (event->attr.mmap || event->attr.mmap_data)
5010 atomic_dec(&nr_mmap_events);
5011 if (event->attr.build_id)
5012 atomic_dec(&nr_build_id_events);
5013 if (event->attr.comm)
5014 atomic_dec(&nr_comm_events);
5015 if (event->attr.namespaces)
5016 atomic_dec(&nr_namespaces_events);
5017 if (event->attr.cgroup)
5018 atomic_dec(&nr_cgroup_events);
5019 if (event->attr.task)
5020 atomic_dec(&nr_task_events);
5021 if (event->attr.freq)
5022 unaccount_freq_event();
5023 if (event->attr.context_switch) {
5025 atomic_dec(&nr_switch_events);
5027 if (is_cgroup_event(event))
5029 if (has_branch_stack(event))
5031 if (event->attr.ksymbol)
5032 atomic_dec(&nr_ksymbol_events);
5033 if (event->attr.bpf_event)
5034 atomic_dec(&nr_bpf_events);
5035 if (event->attr.text_poke)
5036 atomic_dec(&nr_text_poke_events);
5039 if (!atomic_add_unless(&perf_sched_count, -1, 1))
5040 schedule_delayed_work(&perf_sched_work, HZ);
5043 unaccount_pmu_sb_event(event);
5046 static void perf_sched_delayed(struct work_struct *work)
5048 mutex_lock(&perf_sched_mutex);
5049 if (atomic_dec_and_test(&perf_sched_count))
5050 static_branch_disable(&perf_sched_events);
5051 mutex_unlock(&perf_sched_mutex);
5055 * The following implement mutual exclusion of events on "exclusive" pmus
5056 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
5057 * at a time, so we disallow creating events that might conflict, namely:
5059 * 1) cpu-wide events in the presence of per-task events,
5060 * 2) per-task events in the presence of cpu-wide events,
5061 * 3) two matching events on the same perf_event_context.
5063 * The former two cases are handled in the allocation path (perf_event_alloc(),
5064 * _free_event()), the latter -- before the first perf_install_in_context().
5066 static int exclusive_event_init(struct perf_event *event)
5068 struct pmu *pmu = event->pmu;
5070 if (!is_exclusive_pmu(pmu))
5074 * Prevent co-existence of per-task and cpu-wide events on the
5075 * same exclusive pmu.
5077 * Negative pmu::exclusive_cnt means there are cpu-wide
5078 * events on this "exclusive" pmu, positive means there are
5081 * Since this is called in perf_event_alloc() path, event::ctx
5082 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
5083 * to mean "per-task event", because unlike other attach states it
5084 * never gets cleared.
5086 if (event->attach_state & PERF_ATTACH_TASK) {
5087 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
5090 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
5097 static void exclusive_event_destroy(struct perf_event *event)
5099 struct pmu *pmu = event->pmu;
5101 if (!is_exclusive_pmu(pmu))
5104 /* see comment in exclusive_event_init() */
5105 if (event->attach_state & PERF_ATTACH_TASK)
5106 atomic_dec(&pmu->exclusive_cnt);
5108 atomic_inc(&pmu->exclusive_cnt);
5111 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
5113 if ((e1->pmu == e2->pmu) &&
5114 (e1->cpu == e2->cpu ||
5121 static bool exclusive_event_installable(struct perf_event *event,
5122 struct perf_event_context *ctx)
5124 struct perf_event *iter_event;
5125 struct pmu *pmu = event->pmu;
5127 lockdep_assert_held(&ctx->mutex);
5129 if (!is_exclusive_pmu(pmu))
5132 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
5133 if (exclusive_event_match(iter_event, event))
5140 static void perf_addr_filters_splice(struct perf_event *event,
5141 struct list_head *head);
5143 static void _free_event(struct perf_event *event)
5145 irq_work_sync(&event->pending_irq);
5147 unaccount_event(event);
5149 security_perf_event_free(event);
5153 * Can happen when we close an event with re-directed output.
5155 * Since we have a 0 refcount, perf_mmap_close() will skip
5156 * over us; possibly making our ring_buffer_put() the last.
5158 mutex_lock(&event->mmap_mutex);
5159 ring_buffer_attach(event, NULL);
5160 mutex_unlock(&event->mmap_mutex);
5163 if (is_cgroup_event(event))
5164 perf_detach_cgroup(event);
5166 if (!event->parent) {
5167 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
5168 put_callchain_buffers();
5171 perf_event_free_bpf_prog(event);
5172 perf_addr_filters_splice(event, NULL);
5173 kfree(event->addr_filter_ranges);
5176 event->destroy(event);
5179 * Must be after ->destroy(), due to uprobe_perf_close() using
5182 if (event->hw.target)
5183 put_task_struct(event->hw.target);
5186 put_pmu_ctx(event->pmu_ctx);
5189 * perf_event_free_task() relies on put_ctx() being 'last', in particular
5190 * all task references must be cleaned up.
5193 put_ctx(event->ctx);
5195 exclusive_event_destroy(event);
5196 module_put(event->pmu->module);
5198 call_rcu(&event->rcu_head, free_event_rcu);
5202 * Used to free events which have a known refcount of 1, such as in error paths
5203 * where the event isn't exposed yet and inherited events.
5205 static void free_event(struct perf_event *event)
5207 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
5208 "unexpected event refcount: %ld; ptr=%p\n",
5209 atomic_long_read(&event->refcount), event)) {
5210 /* leak to avoid use-after-free */
5218 * Remove user event from the owner task.
5220 static void perf_remove_from_owner(struct perf_event *event)
5222 struct task_struct *owner;
5226 * Matches the smp_store_release() in perf_event_exit_task(). If we
5227 * observe !owner it means the list deletion is complete and we can
5228 * indeed free this event, otherwise we need to serialize on
5229 * owner->perf_event_mutex.
5231 owner = READ_ONCE(event->owner);
5234 * Since delayed_put_task_struct() also drops the last
5235 * task reference we can safely take a new reference
5236 * while holding the rcu_read_lock().
5238 get_task_struct(owner);
5244 * If we're here through perf_event_exit_task() we're already
5245 * holding ctx->mutex which would be an inversion wrt. the
5246 * normal lock order.
5248 * However we can safely take this lock because its the child
5251 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
5254 * We have to re-check the event->owner field, if it is cleared
5255 * we raced with perf_event_exit_task(), acquiring the mutex
5256 * ensured they're done, and we can proceed with freeing the
5260 list_del_init(&event->owner_entry);
5261 smp_store_release(&event->owner, NULL);
5263 mutex_unlock(&owner->perf_event_mutex);
5264 put_task_struct(owner);
5268 static void put_event(struct perf_event *event)
5270 if (!atomic_long_dec_and_test(&event->refcount))
5277 * Kill an event dead; while event:refcount will preserve the event
5278 * object, it will not preserve its functionality. Once the last 'user'
5279 * gives up the object, we'll destroy the thing.
5281 int perf_event_release_kernel(struct perf_event *event)
5283 struct perf_event_context *ctx = event->ctx;
5284 struct perf_event *child, *tmp;
5285 LIST_HEAD(free_list);
5288 * If we got here through err_alloc: free_event(event); we will not
5289 * have attached to a context yet.
5292 WARN_ON_ONCE(event->attach_state &
5293 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
5297 if (!is_kernel_event(event))
5298 perf_remove_from_owner(event);
5300 ctx = perf_event_ctx_lock(event);
5301 WARN_ON_ONCE(ctx->parent_ctx);
5304 * Mark this event as STATE_DEAD, there is no external reference to it
5307 * Anybody acquiring event->child_mutex after the below loop _must_
5308 * also see this, most importantly inherit_event() which will avoid
5309 * placing more children on the list.
5311 * Thus this guarantees that we will in fact observe and kill _ALL_
5314 perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD);
5316 perf_event_ctx_unlock(event, ctx);
5319 mutex_lock(&event->child_mutex);
5320 list_for_each_entry(child, &event->child_list, child_list) {
5323 * Cannot change, child events are not migrated, see the
5324 * comment with perf_event_ctx_lock_nested().
5326 ctx = READ_ONCE(child->ctx);
5328 * Since child_mutex nests inside ctx::mutex, we must jump
5329 * through hoops. We start by grabbing a reference on the ctx.
5331 * Since the event cannot get freed while we hold the
5332 * child_mutex, the context must also exist and have a !0
5338 * Now that we have a ctx ref, we can drop child_mutex, and
5339 * acquire ctx::mutex without fear of it going away. Then we
5340 * can re-acquire child_mutex.
5342 mutex_unlock(&event->child_mutex);
5343 mutex_lock(&ctx->mutex);
5344 mutex_lock(&event->child_mutex);
5347 * Now that we hold ctx::mutex and child_mutex, revalidate our
5348 * state, if child is still the first entry, it didn't get freed
5349 * and we can continue doing so.
5351 tmp = list_first_entry_or_null(&event->child_list,
5352 struct perf_event, child_list);
5354 perf_remove_from_context(child, DETACH_GROUP);
5355 list_move(&child->child_list, &free_list);
5357 * This matches the refcount bump in inherit_event();
5358 * this can't be the last reference.
5363 mutex_unlock(&event->child_mutex);
5364 mutex_unlock(&ctx->mutex);
5368 mutex_unlock(&event->child_mutex);
5370 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5371 void *var = &child->ctx->refcount;
5373 list_del(&child->child_list);
5377 * Wake any perf_event_free_task() waiting for this event to be
5380 smp_mb(); /* pairs with wait_var_event() */
5385 put_event(event); /* Must be the 'last' reference */
5388 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5391 * Called when the last reference to the file is gone.
5393 static int perf_release(struct inode *inode, struct file *file)
5395 perf_event_release_kernel(file->private_data);
5399 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5401 struct perf_event *child;
5407 mutex_lock(&event->child_mutex);
5409 (void)perf_event_read(event, false);
5410 total += perf_event_count(event);
5412 *enabled += event->total_time_enabled +
5413 atomic64_read(&event->child_total_time_enabled);
5414 *running += event->total_time_running +
5415 atomic64_read(&event->child_total_time_running);
5417 list_for_each_entry(child, &event->child_list, child_list) {
5418 (void)perf_event_read(child, false);
5419 total += perf_event_count(child);
5420 *enabled += child->total_time_enabled;
5421 *running += child->total_time_running;
5423 mutex_unlock(&event->child_mutex);
5428 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5430 struct perf_event_context *ctx;
5433 ctx = perf_event_ctx_lock(event);
5434 count = __perf_event_read_value(event, enabled, running);
5435 perf_event_ctx_unlock(event, ctx);
5439 EXPORT_SYMBOL_GPL(perf_event_read_value);
5441 static int __perf_read_group_add(struct perf_event *leader,
5442 u64 read_format, u64 *values)
5444 struct perf_event_context *ctx = leader->ctx;
5445 struct perf_event *sub, *parent;
5446 unsigned long flags;
5447 int n = 1; /* skip @nr */
5450 ret = perf_event_read(leader, true);
5454 raw_spin_lock_irqsave(&ctx->lock, flags);
5456 * Verify the grouping between the parent and child (inherited)
5457 * events is still in tact.
5460 * - leader->ctx->lock pins leader->sibling_list
5461 * - parent->child_mutex pins parent->child_list
5462 * - parent->ctx->mutex pins parent->sibling_list
5464 * Because parent->ctx != leader->ctx (and child_list nests inside
5465 * ctx->mutex), group destruction is not atomic between children, also
5466 * see perf_event_release_kernel(). Additionally, parent can grow the
5469 * Therefore it is possible to have parent and child groups in a
5470 * different configuration and summing over such a beast makes no sense
5475 parent = leader->parent;
5477 (parent->group_generation != leader->group_generation ||
5478 parent->nr_siblings != leader->nr_siblings)) {
5484 * Since we co-schedule groups, {enabled,running} times of siblings
5485 * will be identical to those of the leader, so we only publish one
5488 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5489 values[n++] += leader->total_time_enabled +
5490 atomic64_read(&leader->child_total_time_enabled);
5493 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5494 values[n++] += leader->total_time_running +
5495 atomic64_read(&leader->child_total_time_running);
5499 * Write {count,id} tuples for every sibling.
5501 values[n++] += perf_event_count(leader);
5502 if (read_format & PERF_FORMAT_ID)
5503 values[n++] = primary_event_id(leader);
5504 if (read_format & PERF_FORMAT_LOST)
5505 values[n++] = atomic64_read(&leader->lost_samples);
5507 for_each_sibling_event(sub, leader) {
5508 values[n++] += perf_event_count(sub);
5509 if (read_format & PERF_FORMAT_ID)
5510 values[n++] = primary_event_id(sub);
5511 if (read_format & PERF_FORMAT_LOST)
5512 values[n++] = atomic64_read(&sub->lost_samples);
5516 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5520 static int perf_read_group(struct perf_event *event,
5521 u64 read_format, char __user *buf)
5523 struct perf_event *leader = event->group_leader, *child;
5524 struct perf_event_context *ctx = leader->ctx;
5528 lockdep_assert_held(&ctx->mutex);
5530 values = kzalloc(event->read_size, GFP_KERNEL);
5534 values[0] = 1 + leader->nr_siblings;
5536 mutex_lock(&leader->child_mutex);
5538 ret = __perf_read_group_add(leader, read_format, values);
5542 list_for_each_entry(child, &leader->child_list, child_list) {
5543 ret = __perf_read_group_add(child, read_format, values);
5548 mutex_unlock(&leader->child_mutex);
5550 ret = event->read_size;
5551 if (copy_to_user(buf, values, event->read_size))
5556 mutex_unlock(&leader->child_mutex);
5562 static int perf_read_one(struct perf_event *event,
5563 u64 read_format, char __user *buf)
5565 u64 enabled, running;
5569 values[n++] = __perf_event_read_value(event, &enabled, &running);
5570 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5571 values[n++] = enabled;
5572 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5573 values[n++] = running;
5574 if (read_format & PERF_FORMAT_ID)
5575 values[n++] = primary_event_id(event);
5576 if (read_format & PERF_FORMAT_LOST)
5577 values[n++] = atomic64_read(&event->lost_samples);
5579 if (copy_to_user(buf, values, n * sizeof(u64)))
5582 return n * sizeof(u64);
5585 static bool is_event_hup(struct perf_event *event)
5589 if (event->state > PERF_EVENT_STATE_EXIT)
5592 mutex_lock(&event->child_mutex);
5593 no_children = list_empty(&event->child_list);
5594 mutex_unlock(&event->child_mutex);
5599 * Read the performance event - simple non blocking version for now
5602 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5604 u64 read_format = event->attr.read_format;
5608 * Return end-of-file for a read on an event that is in
5609 * error state (i.e. because it was pinned but it couldn't be
5610 * scheduled on to the CPU at some point).
5612 if (event->state == PERF_EVENT_STATE_ERROR)
5615 if (count < event->read_size)
5618 WARN_ON_ONCE(event->ctx->parent_ctx);
5619 if (read_format & PERF_FORMAT_GROUP)
5620 ret = perf_read_group(event, read_format, buf);
5622 ret = perf_read_one(event, read_format, buf);
5628 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5630 struct perf_event *event = file->private_data;
5631 struct perf_event_context *ctx;
5634 ret = security_perf_event_read(event);
5638 ctx = perf_event_ctx_lock(event);
5639 ret = __perf_read(event, buf, count);
5640 perf_event_ctx_unlock(event, ctx);
5645 static __poll_t perf_poll(struct file *file, poll_table *wait)
5647 struct perf_event *event = file->private_data;
5648 struct perf_buffer *rb;
5649 __poll_t events = EPOLLHUP;
5651 poll_wait(file, &event->waitq, wait);
5653 if (is_event_hup(event))
5657 * Pin the event->rb by taking event->mmap_mutex; otherwise
5658 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5660 mutex_lock(&event->mmap_mutex);
5663 events = atomic_xchg(&rb->poll, 0);
5664 mutex_unlock(&event->mmap_mutex);
5668 static void _perf_event_reset(struct perf_event *event)
5670 (void)perf_event_read(event, false);
5671 local64_set(&event->count, 0);
5672 perf_event_update_userpage(event);
5675 /* Assume it's not an event with inherit set. */
5676 u64 perf_event_pause(struct perf_event *event, bool reset)
5678 struct perf_event_context *ctx;
5681 ctx = perf_event_ctx_lock(event);
5682 WARN_ON_ONCE(event->attr.inherit);
5683 _perf_event_disable(event);
5684 count = local64_read(&event->count);
5686 local64_set(&event->count, 0);
5687 perf_event_ctx_unlock(event, ctx);
5691 EXPORT_SYMBOL_GPL(perf_event_pause);
5694 * Holding the top-level event's child_mutex means that any
5695 * descendant process that has inherited this event will block
5696 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5697 * task existence requirements of perf_event_enable/disable.
5699 static void perf_event_for_each_child(struct perf_event *event,
5700 void (*func)(struct perf_event *))
5702 struct perf_event *child;
5704 WARN_ON_ONCE(event->ctx->parent_ctx);
5706 mutex_lock(&event->child_mutex);
5708 list_for_each_entry(child, &event->child_list, child_list)
5710 mutex_unlock(&event->child_mutex);
5713 static void perf_event_for_each(struct perf_event *event,
5714 void (*func)(struct perf_event *))
5716 struct perf_event_context *ctx = event->ctx;
5717 struct perf_event *sibling;
5719 lockdep_assert_held(&ctx->mutex);
5721 event = event->group_leader;
5723 perf_event_for_each_child(event, func);
5724 for_each_sibling_event(sibling, event)
5725 perf_event_for_each_child(sibling, func);
5728 static void __perf_event_period(struct perf_event *event,
5729 struct perf_cpu_context *cpuctx,
5730 struct perf_event_context *ctx,
5733 u64 value = *((u64 *)info);
5736 if (event->attr.freq) {
5737 event->attr.sample_freq = value;
5739 event->attr.sample_period = value;
5740 event->hw.sample_period = value;
5743 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5745 perf_pmu_disable(event->pmu);
5747 * We could be throttled; unthrottle now to avoid the tick
5748 * trying to unthrottle while we already re-started the event.
5750 if (event->hw.interrupts == MAX_INTERRUPTS) {
5751 event->hw.interrupts = 0;
5752 perf_log_throttle(event, 1);
5754 event->pmu->stop(event, PERF_EF_UPDATE);
5757 local64_set(&event->hw.period_left, 0);
5760 event->pmu->start(event, PERF_EF_RELOAD);
5761 perf_pmu_enable(event->pmu);
5765 static int perf_event_check_period(struct perf_event *event, u64 value)
5767 return event->pmu->check_period(event, value);
5770 static int _perf_event_period(struct perf_event *event, u64 value)
5772 if (!is_sampling_event(event))
5778 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5781 if (perf_event_check_period(event, value))
5784 if (!event->attr.freq && (value & (1ULL << 63)))
5787 event_function_call(event, __perf_event_period, &value);
5792 int perf_event_period(struct perf_event *event, u64 value)
5794 struct perf_event_context *ctx;
5797 ctx = perf_event_ctx_lock(event);
5798 ret = _perf_event_period(event, value);
5799 perf_event_ctx_unlock(event, ctx);
5803 EXPORT_SYMBOL_GPL(perf_event_period);
5805 static const struct file_operations perf_fops;
5807 static inline int perf_fget_light(int fd, struct fd *p)
5809 struct fd f = fdget(fd);
5813 if (f.file->f_op != &perf_fops) {
5821 static int perf_event_set_output(struct perf_event *event,
5822 struct perf_event *output_event);
5823 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5824 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5825 struct perf_event_attr *attr);
5827 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5829 void (*func)(struct perf_event *);
5833 case PERF_EVENT_IOC_ENABLE:
5834 func = _perf_event_enable;
5836 case PERF_EVENT_IOC_DISABLE:
5837 func = _perf_event_disable;
5839 case PERF_EVENT_IOC_RESET:
5840 func = _perf_event_reset;
5843 case PERF_EVENT_IOC_REFRESH:
5844 return _perf_event_refresh(event, arg);
5846 case PERF_EVENT_IOC_PERIOD:
5850 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5853 return _perf_event_period(event, value);
5855 case PERF_EVENT_IOC_ID:
5857 u64 id = primary_event_id(event);
5859 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5864 case PERF_EVENT_IOC_SET_OUTPUT:
5868 struct perf_event *output_event;
5870 ret = perf_fget_light(arg, &output);
5873 output_event = output.file->private_data;
5874 ret = perf_event_set_output(event, output_event);
5877 ret = perf_event_set_output(event, NULL);
5882 case PERF_EVENT_IOC_SET_FILTER:
5883 return perf_event_set_filter(event, (void __user *)arg);
5885 case PERF_EVENT_IOC_SET_BPF:
5887 struct bpf_prog *prog;
5890 prog = bpf_prog_get(arg);
5892 return PTR_ERR(prog);
5894 err = perf_event_set_bpf_prog(event, prog, 0);
5903 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5904 struct perf_buffer *rb;
5907 rb = rcu_dereference(event->rb);
5908 if (!rb || !rb->nr_pages) {
5912 rb_toggle_paused(rb, !!arg);
5917 case PERF_EVENT_IOC_QUERY_BPF:
5918 return perf_event_query_prog_array(event, (void __user *)arg);
5920 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5921 struct perf_event_attr new_attr;
5922 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5928 return perf_event_modify_attr(event, &new_attr);
5934 if (flags & PERF_IOC_FLAG_GROUP)
5935 perf_event_for_each(event, func);
5937 perf_event_for_each_child(event, func);
5942 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5944 struct perf_event *event = file->private_data;
5945 struct perf_event_context *ctx;
5948 /* Treat ioctl like writes as it is likely a mutating operation. */
5949 ret = security_perf_event_write(event);
5953 ctx = perf_event_ctx_lock(event);
5954 ret = _perf_ioctl(event, cmd, arg);
5955 perf_event_ctx_unlock(event, ctx);
5960 #ifdef CONFIG_COMPAT
5961 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5964 switch (_IOC_NR(cmd)) {
5965 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5966 case _IOC_NR(PERF_EVENT_IOC_ID):
5967 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5968 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5969 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5970 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5971 cmd &= ~IOCSIZE_MASK;
5972 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5976 return perf_ioctl(file, cmd, arg);
5979 # define perf_compat_ioctl NULL
5982 int perf_event_task_enable(void)
5984 struct perf_event_context *ctx;
5985 struct perf_event *event;
5987 mutex_lock(¤t->perf_event_mutex);
5988 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5989 ctx = perf_event_ctx_lock(event);
5990 perf_event_for_each_child(event, _perf_event_enable);
5991 perf_event_ctx_unlock(event, ctx);
5993 mutex_unlock(¤t->perf_event_mutex);
5998 int perf_event_task_disable(void)
6000 struct perf_event_context *ctx;
6001 struct perf_event *event;
6003 mutex_lock(¤t->perf_event_mutex);
6004 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
6005 ctx = perf_event_ctx_lock(event);
6006 perf_event_for_each_child(event, _perf_event_disable);
6007 perf_event_ctx_unlock(event, ctx);
6009 mutex_unlock(¤t->perf_event_mutex);
6014 static int perf_event_index(struct perf_event *event)
6016 if (event->hw.state & PERF_HES_STOPPED)
6019 if (event->state != PERF_EVENT_STATE_ACTIVE)
6022 return event->pmu->event_idx(event);
6025 static void perf_event_init_userpage(struct perf_event *event)
6027 struct perf_event_mmap_page *userpg;
6028 struct perf_buffer *rb;
6031 rb = rcu_dereference(event->rb);
6035 userpg = rb->user_page;
6037 /* Allow new userspace to detect that bit 0 is deprecated */
6038 userpg->cap_bit0_is_deprecated = 1;
6039 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
6040 userpg->data_offset = PAGE_SIZE;
6041 userpg->data_size = perf_data_size(rb);
6047 void __weak arch_perf_update_userpage(
6048 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
6053 * Callers need to ensure there can be no nesting of this function, otherwise
6054 * the seqlock logic goes bad. We can not serialize this because the arch
6055 * code calls this from NMI context.
6057 void perf_event_update_userpage(struct perf_event *event)
6059 struct perf_event_mmap_page *userpg;
6060 struct perf_buffer *rb;
6061 u64 enabled, running, now;
6064 rb = rcu_dereference(event->rb);
6069 * compute total_time_enabled, total_time_running
6070 * based on snapshot values taken when the event
6071 * was last scheduled in.
6073 * we cannot simply called update_context_time()
6074 * because of locking issue as we can be called in
6077 calc_timer_values(event, &now, &enabled, &running);
6079 userpg = rb->user_page;
6081 * Disable preemption to guarantee consistent time stamps are stored to
6087 userpg->index = perf_event_index(event);
6088 userpg->offset = perf_event_count(event);
6090 userpg->offset -= local64_read(&event->hw.prev_count);
6092 userpg->time_enabled = enabled +
6093 atomic64_read(&event->child_total_time_enabled);
6095 userpg->time_running = running +
6096 atomic64_read(&event->child_total_time_running);
6098 arch_perf_update_userpage(event, userpg, now);
6106 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
6108 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
6110 struct perf_event *event = vmf->vma->vm_file->private_data;
6111 struct perf_buffer *rb;
6112 vm_fault_t ret = VM_FAULT_SIGBUS;
6114 if (vmf->flags & FAULT_FLAG_MKWRITE) {
6115 if (vmf->pgoff == 0)
6121 rb = rcu_dereference(event->rb);
6125 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
6128 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
6132 get_page(vmf->page);
6133 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
6134 vmf->page->index = vmf->pgoff;
6143 static void ring_buffer_attach(struct perf_event *event,
6144 struct perf_buffer *rb)
6146 struct perf_buffer *old_rb = NULL;
6147 unsigned long flags;
6149 WARN_ON_ONCE(event->parent);
6153 * Should be impossible, we set this when removing
6154 * event->rb_entry and wait/clear when adding event->rb_entry.
6156 WARN_ON_ONCE(event->rcu_pending);
6159 spin_lock_irqsave(&old_rb->event_lock, flags);
6160 list_del_rcu(&event->rb_entry);
6161 spin_unlock_irqrestore(&old_rb->event_lock, flags);
6163 event->rcu_batches = get_state_synchronize_rcu();
6164 event->rcu_pending = 1;
6168 if (event->rcu_pending) {
6169 cond_synchronize_rcu(event->rcu_batches);
6170 event->rcu_pending = 0;
6173 spin_lock_irqsave(&rb->event_lock, flags);
6174 list_add_rcu(&event->rb_entry, &rb->event_list);
6175 spin_unlock_irqrestore(&rb->event_lock, flags);
6179 * Avoid racing with perf_mmap_close(AUX): stop the event
6180 * before swizzling the event::rb pointer; if it's getting
6181 * unmapped, its aux_mmap_count will be 0 and it won't
6182 * restart. See the comment in __perf_pmu_output_stop().
6184 * Data will inevitably be lost when set_output is done in
6185 * mid-air, but then again, whoever does it like this is
6186 * not in for the data anyway.
6189 perf_event_stop(event, 0);
6191 rcu_assign_pointer(event->rb, rb);
6194 ring_buffer_put(old_rb);
6196 * Since we detached before setting the new rb, so that we
6197 * could attach the new rb, we could have missed a wakeup.
6200 wake_up_all(&event->waitq);
6204 static void ring_buffer_wakeup(struct perf_event *event)
6206 struct perf_buffer *rb;
6209 event = event->parent;
6212 rb = rcu_dereference(event->rb);
6214 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
6215 wake_up_all(&event->waitq);
6220 struct perf_buffer *ring_buffer_get(struct perf_event *event)
6222 struct perf_buffer *rb;
6225 event = event->parent;
6228 rb = rcu_dereference(event->rb);
6230 if (!refcount_inc_not_zero(&rb->refcount))
6238 void ring_buffer_put(struct perf_buffer *rb)
6240 if (!refcount_dec_and_test(&rb->refcount))
6243 WARN_ON_ONCE(!list_empty(&rb->event_list));
6245 call_rcu(&rb->rcu_head, rb_free_rcu);
6248 static void perf_mmap_open(struct vm_area_struct *vma)
6250 struct perf_event *event = vma->vm_file->private_data;
6252 atomic_inc(&event->mmap_count);
6253 atomic_inc(&event->rb->mmap_count);
6256 atomic_inc(&event->rb->aux_mmap_count);
6258 if (event->pmu->event_mapped)
6259 event->pmu->event_mapped(event, vma->vm_mm);
6262 static void perf_pmu_output_stop(struct perf_event *event);
6265 * A buffer can be mmap()ed multiple times; either directly through the same
6266 * event, or through other events by use of perf_event_set_output().
6268 * In order to undo the VM accounting done by perf_mmap() we need to destroy
6269 * the buffer here, where we still have a VM context. This means we need
6270 * to detach all events redirecting to us.
6272 static void perf_mmap_close(struct vm_area_struct *vma)
6274 struct perf_event *event = vma->vm_file->private_data;
6275 struct perf_buffer *rb = ring_buffer_get(event);
6276 struct user_struct *mmap_user = rb->mmap_user;
6277 int mmap_locked = rb->mmap_locked;
6278 unsigned long size = perf_data_size(rb);
6279 bool detach_rest = false;
6281 if (event->pmu->event_unmapped)
6282 event->pmu->event_unmapped(event, vma->vm_mm);
6285 * rb->aux_mmap_count will always drop before rb->mmap_count and
6286 * event->mmap_count, so it is ok to use event->mmap_mutex to
6287 * serialize with perf_mmap here.
6289 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
6290 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
6292 * Stop all AUX events that are writing to this buffer,
6293 * so that we can free its AUX pages and corresponding PMU
6294 * data. Note that after rb::aux_mmap_count dropped to zero,
6295 * they won't start any more (see perf_aux_output_begin()).
6297 perf_pmu_output_stop(event);
6299 /* now it's safe to free the pages */
6300 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
6301 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
6303 /* this has to be the last one */
6305 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
6307 mutex_unlock(&event->mmap_mutex);
6310 if (atomic_dec_and_test(&rb->mmap_count))
6313 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
6316 ring_buffer_attach(event, NULL);
6317 mutex_unlock(&event->mmap_mutex);
6319 /* If there's still other mmap()s of this buffer, we're done. */
6324 * No other mmap()s, detach from all other events that might redirect
6325 * into the now unreachable buffer. Somewhat complicated by the
6326 * fact that rb::event_lock otherwise nests inside mmap_mutex.
6330 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
6331 if (!atomic_long_inc_not_zero(&event->refcount)) {
6333 * This event is en-route to free_event() which will
6334 * detach it and remove it from the list.
6340 mutex_lock(&event->mmap_mutex);
6342 * Check we didn't race with perf_event_set_output() which can
6343 * swizzle the rb from under us while we were waiting to
6344 * acquire mmap_mutex.
6346 * If we find a different rb; ignore this event, a next
6347 * iteration will no longer find it on the list. We have to
6348 * still restart the iteration to make sure we're not now
6349 * iterating the wrong list.
6351 if (event->rb == rb)
6352 ring_buffer_attach(event, NULL);
6354 mutex_unlock(&event->mmap_mutex);
6358 * Restart the iteration; either we're on the wrong list or
6359 * destroyed its integrity by doing a deletion.
6366 * It could be there's still a few 0-ref events on the list; they'll
6367 * get cleaned up by free_event() -- they'll also still have their
6368 * ref on the rb and will free it whenever they are done with it.
6370 * Aside from that, this buffer is 'fully' detached and unmapped,
6371 * undo the VM accounting.
6374 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6375 &mmap_user->locked_vm);
6376 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6377 free_uid(mmap_user);
6380 ring_buffer_put(rb); /* could be last */
6383 static const struct vm_operations_struct perf_mmap_vmops = {
6384 .open = perf_mmap_open,
6385 .close = perf_mmap_close, /* non mergeable */
6386 .fault = perf_mmap_fault,
6387 .page_mkwrite = perf_mmap_fault,
6390 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6392 struct perf_event *event = file->private_data;
6393 unsigned long user_locked, user_lock_limit;
6394 struct user_struct *user = current_user();
6395 struct perf_buffer *rb = NULL;
6396 unsigned long locked, lock_limit;
6397 unsigned long vma_size;
6398 unsigned long nr_pages;
6399 long user_extra = 0, extra = 0;
6400 int ret = 0, flags = 0;
6403 * Don't allow mmap() of inherited per-task counters. This would
6404 * create a performance issue due to all children writing to the
6407 if (event->cpu == -1 && event->attr.inherit)
6410 if (!(vma->vm_flags & VM_SHARED))
6413 ret = security_perf_event_read(event);
6417 vma_size = vma->vm_end - vma->vm_start;
6419 if (vma->vm_pgoff == 0) {
6420 nr_pages = (vma_size / PAGE_SIZE) - 1;
6423 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6424 * mapped, all subsequent mappings should have the same size
6425 * and offset. Must be above the normal perf buffer.
6427 u64 aux_offset, aux_size;
6432 nr_pages = vma_size / PAGE_SIZE;
6434 mutex_lock(&event->mmap_mutex);
6441 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6442 aux_size = READ_ONCE(rb->user_page->aux_size);
6444 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6447 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6450 /* already mapped with a different offset */
6451 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6454 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6457 /* already mapped with a different size */
6458 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6461 if (!is_power_of_2(nr_pages))
6464 if (!atomic_inc_not_zero(&rb->mmap_count))
6467 if (rb_has_aux(rb)) {
6468 atomic_inc(&rb->aux_mmap_count);
6473 atomic_set(&rb->aux_mmap_count, 1);
6474 user_extra = nr_pages;
6480 * If we have rb pages ensure they're a power-of-two number, so we
6481 * can do bitmasks instead of modulo.
6483 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6486 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6489 WARN_ON_ONCE(event->ctx->parent_ctx);
6491 mutex_lock(&event->mmap_mutex);
6493 if (data_page_nr(event->rb) != nr_pages) {
6498 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6500 * Raced against perf_mmap_close(); remove the
6501 * event and try again.
6503 ring_buffer_attach(event, NULL);
6504 mutex_unlock(&event->mmap_mutex);
6511 user_extra = nr_pages + 1;
6514 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6517 * Increase the limit linearly with more CPUs:
6519 user_lock_limit *= num_online_cpus();
6521 user_locked = atomic_long_read(&user->locked_vm);
6524 * sysctl_perf_event_mlock may have changed, so that
6525 * user->locked_vm > user_lock_limit
6527 if (user_locked > user_lock_limit)
6528 user_locked = user_lock_limit;
6529 user_locked += user_extra;
6531 if (user_locked > user_lock_limit) {
6533 * charge locked_vm until it hits user_lock_limit;
6534 * charge the rest from pinned_vm
6536 extra = user_locked - user_lock_limit;
6537 user_extra -= extra;
6540 lock_limit = rlimit(RLIMIT_MEMLOCK);
6541 lock_limit >>= PAGE_SHIFT;
6542 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6544 if ((locked > lock_limit) && perf_is_paranoid() &&
6545 !capable(CAP_IPC_LOCK)) {
6550 WARN_ON(!rb && event->rb);
6552 if (vma->vm_flags & VM_WRITE)
6553 flags |= RING_BUFFER_WRITABLE;
6556 rb = rb_alloc(nr_pages,
6557 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6565 atomic_set(&rb->mmap_count, 1);
6566 rb->mmap_user = get_current_user();
6567 rb->mmap_locked = extra;
6569 ring_buffer_attach(event, rb);
6571 perf_event_update_time(event);
6572 perf_event_init_userpage(event);
6573 perf_event_update_userpage(event);
6575 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6576 event->attr.aux_watermark, flags);
6578 rb->aux_mmap_locked = extra;
6583 atomic_long_add(user_extra, &user->locked_vm);
6584 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6586 atomic_inc(&event->mmap_count);
6588 atomic_dec(&rb->mmap_count);
6591 mutex_unlock(&event->mmap_mutex);
6594 * Since pinned accounting is per vm we cannot allow fork() to copy our
6597 vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP);
6598 vma->vm_ops = &perf_mmap_vmops;
6600 if (event->pmu->event_mapped)
6601 event->pmu->event_mapped(event, vma->vm_mm);
6606 static int perf_fasync(int fd, struct file *filp, int on)
6608 struct inode *inode = file_inode(filp);
6609 struct perf_event *event = filp->private_data;
6613 retval = fasync_helper(fd, filp, on, &event->fasync);
6614 inode_unlock(inode);
6622 static const struct file_operations perf_fops = {
6623 .llseek = no_llseek,
6624 .release = perf_release,
6627 .unlocked_ioctl = perf_ioctl,
6628 .compat_ioctl = perf_compat_ioctl,
6630 .fasync = perf_fasync,
6636 * If there's data, ensure we set the poll() state and publish everything
6637 * to user-space before waking everybody up.
6640 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6642 /* only the parent has fasync state */
6644 event = event->parent;
6645 return &event->fasync;
6648 void perf_event_wakeup(struct perf_event *event)
6650 ring_buffer_wakeup(event);
6652 if (event->pending_kill) {
6653 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6654 event->pending_kill = 0;
6658 static void perf_sigtrap(struct perf_event *event)
6661 * We'd expect this to only occur if the irq_work is delayed and either
6662 * ctx->task or current has changed in the meantime. This can be the
6663 * case on architectures that do not implement arch_irq_work_raise().
6665 if (WARN_ON_ONCE(event->ctx->task != current))
6669 * Both perf_pending_task() and perf_pending_irq() can race with the
6672 if (current->flags & PF_EXITING)
6675 send_sig_perf((void __user *)event->pending_addr,
6676 event->orig_type, event->attr.sig_data);
6680 * Deliver the pending work in-event-context or follow the context.
6682 static void __perf_pending_irq(struct perf_event *event)
6684 int cpu = READ_ONCE(event->oncpu);
6687 * If the event isn't running; we done. event_sched_out() will have
6688 * taken care of things.
6694 * Yay, we hit home and are in the context of the event.
6696 if (cpu == smp_processor_id()) {
6697 if (event->pending_sigtrap) {
6698 event->pending_sigtrap = 0;
6699 perf_sigtrap(event);
6700 local_dec(&event->ctx->nr_pending);
6702 if (event->pending_disable) {
6703 event->pending_disable = 0;
6704 perf_event_disable_local(event);
6712 * perf_event_disable_inatomic()
6713 * @pending_disable = CPU-A;
6717 * @pending_disable = -1;
6720 * perf_event_disable_inatomic()
6721 * @pending_disable = CPU-B;
6722 * irq_work_queue(); // FAILS
6725 * perf_pending_irq()
6727 * But the event runs on CPU-B and wants disabling there.
6729 irq_work_queue_on(&event->pending_irq, cpu);
6732 static void perf_pending_irq(struct irq_work *entry)
6734 struct perf_event *event = container_of(entry, struct perf_event, pending_irq);
6738 * If we 'fail' here, that's OK, it means recursion is already disabled
6739 * and we won't recurse 'further'.
6741 rctx = perf_swevent_get_recursion_context();
6744 * The wakeup isn't bound to the context of the event -- it can happen
6745 * irrespective of where the event is.
6747 if (event->pending_wakeup) {
6748 event->pending_wakeup = 0;
6749 perf_event_wakeup(event);
6752 __perf_pending_irq(event);
6755 perf_swevent_put_recursion_context(rctx);
6758 static void perf_pending_task(struct callback_head *head)
6760 struct perf_event *event = container_of(head, struct perf_event, pending_task);
6764 * If we 'fail' here, that's OK, it means recursion is already disabled
6765 * and we won't recurse 'further'.
6767 preempt_disable_notrace();
6768 rctx = perf_swevent_get_recursion_context();
6770 if (event->pending_work) {
6771 event->pending_work = 0;
6772 perf_sigtrap(event);
6773 local_dec(&event->ctx->nr_pending);
6777 perf_swevent_put_recursion_context(rctx);
6778 preempt_enable_notrace();
6783 #ifdef CONFIG_GUEST_PERF_EVENTS
6784 struct perf_guest_info_callbacks __rcu *perf_guest_cbs;
6786 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state);
6787 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip);
6788 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr);
6790 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6792 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs)))
6795 rcu_assign_pointer(perf_guest_cbs, cbs);
6796 static_call_update(__perf_guest_state, cbs->state);
6797 static_call_update(__perf_guest_get_ip, cbs->get_ip);
6799 /* Implementing ->handle_intel_pt_intr is optional. */
6800 if (cbs->handle_intel_pt_intr)
6801 static_call_update(__perf_guest_handle_intel_pt_intr,
6802 cbs->handle_intel_pt_intr);
6804 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6806 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6808 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs))
6811 rcu_assign_pointer(perf_guest_cbs, NULL);
6812 static_call_update(__perf_guest_state, (void *)&__static_call_return0);
6813 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0);
6814 static_call_update(__perf_guest_handle_intel_pt_intr,
6815 (void *)&__static_call_return0);
6818 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6822 perf_output_sample_regs(struct perf_output_handle *handle,
6823 struct pt_regs *regs, u64 mask)
6826 DECLARE_BITMAP(_mask, 64);
6828 bitmap_from_u64(_mask, mask);
6829 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6832 val = perf_reg_value(regs, bit);
6833 perf_output_put(handle, val);
6837 static void perf_sample_regs_user(struct perf_regs *regs_user,
6838 struct pt_regs *regs)
6840 if (user_mode(regs)) {
6841 regs_user->abi = perf_reg_abi(current);
6842 regs_user->regs = regs;
6843 } else if (!(current->flags & PF_KTHREAD)) {
6844 perf_get_regs_user(regs_user, regs);
6846 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6847 regs_user->regs = NULL;
6851 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6852 struct pt_regs *regs)
6854 regs_intr->regs = regs;
6855 regs_intr->abi = perf_reg_abi(current);
6860 * Get remaining task size from user stack pointer.
6862 * It'd be better to take stack vma map and limit this more
6863 * precisely, but there's no way to get it safely under interrupt,
6864 * so using TASK_SIZE as limit.
6866 static u64 perf_ustack_task_size(struct pt_regs *regs)
6868 unsigned long addr = perf_user_stack_pointer(regs);
6870 if (!addr || addr >= TASK_SIZE)
6873 return TASK_SIZE - addr;
6877 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6878 struct pt_regs *regs)
6882 /* No regs, no stack pointer, no dump. */
6887 * Check if we fit in with the requested stack size into the:
6889 * If we don't, we limit the size to the TASK_SIZE.
6891 * - remaining sample size
6892 * If we don't, we customize the stack size to
6893 * fit in to the remaining sample size.
6896 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6897 stack_size = min(stack_size, (u16) task_size);
6899 /* Current header size plus static size and dynamic size. */
6900 header_size += 2 * sizeof(u64);
6902 /* Do we fit in with the current stack dump size? */
6903 if ((u16) (header_size + stack_size) < header_size) {
6905 * If we overflow the maximum size for the sample,
6906 * we customize the stack dump size to fit in.
6908 stack_size = USHRT_MAX - header_size - sizeof(u64);
6909 stack_size = round_up(stack_size, sizeof(u64));
6916 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6917 struct pt_regs *regs)
6919 /* Case of a kernel thread, nothing to dump */
6922 perf_output_put(handle, size);
6931 * - the size requested by user or the best one we can fit
6932 * in to the sample max size
6934 * - user stack dump data
6936 * - the actual dumped size
6940 perf_output_put(handle, dump_size);
6943 sp = perf_user_stack_pointer(regs);
6944 rem = __output_copy_user(handle, (void *) sp, dump_size);
6945 dyn_size = dump_size - rem;
6947 perf_output_skip(handle, rem);
6950 perf_output_put(handle, dyn_size);
6954 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6955 struct perf_sample_data *data,
6958 struct perf_event *sampler = event->aux_event;
6959 struct perf_buffer *rb;
6966 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6969 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6972 rb = ring_buffer_get(sampler);
6977 * If this is an NMI hit inside sampling code, don't take
6978 * the sample. See also perf_aux_sample_output().
6980 if (READ_ONCE(rb->aux_in_sampling)) {
6983 size = min_t(size_t, size, perf_aux_size(rb));
6984 data->aux_size = ALIGN(size, sizeof(u64));
6986 ring_buffer_put(rb);
6989 return data->aux_size;
6992 static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6993 struct perf_event *event,
6994 struct perf_output_handle *handle,
6997 unsigned long flags;
7001 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
7002 * paths. If we start calling them in NMI context, they may race with
7003 * the IRQ ones, that is, for example, re-starting an event that's just
7004 * been stopped, which is why we're using a separate callback that
7005 * doesn't change the event state.
7007 * IRQs need to be disabled to prevent IPIs from racing with us.
7009 local_irq_save(flags);
7011 * Guard against NMI hits inside the critical section;
7012 * see also perf_prepare_sample_aux().
7014 WRITE_ONCE(rb->aux_in_sampling, 1);
7017 ret = event->pmu->snapshot_aux(event, handle, size);
7020 WRITE_ONCE(rb->aux_in_sampling, 0);
7021 local_irq_restore(flags);
7026 static void perf_aux_sample_output(struct perf_event *event,
7027 struct perf_output_handle *handle,
7028 struct perf_sample_data *data)
7030 struct perf_event *sampler = event->aux_event;
7031 struct perf_buffer *rb;
7035 if (WARN_ON_ONCE(!sampler || !data->aux_size))
7038 rb = ring_buffer_get(sampler);
7042 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
7045 * An error here means that perf_output_copy() failed (returned a
7046 * non-zero surplus that it didn't copy), which in its current
7047 * enlightened implementation is not possible. If that changes, we'd
7050 if (WARN_ON_ONCE(size < 0))
7054 * The pad comes from ALIGN()ing data->aux_size up to u64 in
7055 * perf_prepare_sample_aux(), so should not be more than that.
7057 pad = data->aux_size - size;
7058 if (WARN_ON_ONCE(pad >= sizeof(u64)))
7063 perf_output_copy(handle, &zero, pad);
7067 ring_buffer_put(rb);
7071 * A set of common sample data types saved even for non-sample records
7072 * when event->attr.sample_id_all is set.
7074 #define PERF_SAMPLE_ID_ALL (PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \
7075 PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID | \
7076 PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER)
7078 static void __perf_event_header__init_id(struct perf_sample_data *data,
7079 struct perf_event *event,
7082 data->type = event->attr.sample_type;
7083 data->sample_flags |= data->type & PERF_SAMPLE_ID_ALL;
7085 if (sample_type & PERF_SAMPLE_TID) {
7086 /* namespace issues */
7087 data->tid_entry.pid = perf_event_pid(event, current);
7088 data->tid_entry.tid = perf_event_tid(event, current);
7091 if (sample_type & PERF_SAMPLE_TIME)
7092 data->time = perf_event_clock(event);
7094 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
7095 data->id = primary_event_id(event);
7097 if (sample_type & PERF_SAMPLE_STREAM_ID)
7098 data->stream_id = event->id;
7100 if (sample_type & PERF_SAMPLE_CPU) {
7101 data->cpu_entry.cpu = raw_smp_processor_id();
7102 data->cpu_entry.reserved = 0;
7106 void perf_event_header__init_id(struct perf_event_header *header,
7107 struct perf_sample_data *data,
7108 struct perf_event *event)
7110 if (event->attr.sample_id_all) {
7111 header->size += event->id_header_size;
7112 __perf_event_header__init_id(data, event, event->attr.sample_type);
7116 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
7117 struct perf_sample_data *data)
7119 u64 sample_type = data->type;
7121 if (sample_type & PERF_SAMPLE_TID)
7122 perf_output_put(handle, data->tid_entry);
7124 if (sample_type & PERF_SAMPLE_TIME)
7125 perf_output_put(handle, data->time);
7127 if (sample_type & PERF_SAMPLE_ID)
7128 perf_output_put(handle, data->id);
7130 if (sample_type & PERF_SAMPLE_STREAM_ID)
7131 perf_output_put(handle, data->stream_id);
7133 if (sample_type & PERF_SAMPLE_CPU)
7134 perf_output_put(handle, data->cpu_entry);
7136 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7137 perf_output_put(handle, data->id);
7140 void perf_event__output_id_sample(struct perf_event *event,
7141 struct perf_output_handle *handle,
7142 struct perf_sample_data *sample)
7144 if (event->attr.sample_id_all)
7145 __perf_event__output_id_sample(handle, sample);
7148 static void perf_output_read_one(struct perf_output_handle *handle,
7149 struct perf_event *event,
7150 u64 enabled, u64 running)
7152 u64 read_format = event->attr.read_format;
7156 values[n++] = perf_event_count(event);
7157 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
7158 values[n++] = enabled +
7159 atomic64_read(&event->child_total_time_enabled);
7161 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
7162 values[n++] = running +
7163 atomic64_read(&event->child_total_time_running);
7165 if (read_format & PERF_FORMAT_ID)
7166 values[n++] = primary_event_id(event);
7167 if (read_format & PERF_FORMAT_LOST)
7168 values[n++] = atomic64_read(&event->lost_samples);
7170 __output_copy(handle, values, n * sizeof(u64));
7173 static void perf_output_read_group(struct perf_output_handle *handle,
7174 struct perf_event *event,
7175 u64 enabled, u64 running)
7177 struct perf_event *leader = event->group_leader, *sub;
7178 u64 read_format = event->attr.read_format;
7179 unsigned long flags;
7184 * Disabling interrupts avoids all counter scheduling
7185 * (context switches, timer based rotation and IPIs).
7187 local_irq_save(flags);
7189 values[n++] = 1 + leader->nr_siblings;
7191 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
7192 values[n++] = enabled;
7194 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
7195 values[n++] = running;
7197 if ((leader != event) &&
7198 (leader->state == PERF_EVENT_STATE_ACTIVE))
7199 leader->pmu->read(leader);
7201 values[n++] = perf_event_count(leader);
7202 if (read_format & PERF_FORMAT_ID)
7203 values[n++] = primary_event_id(leader);
7204 if (read_format & PERF_FORMAT_LOST)
7205 values[n++] = atomic64_read(&leader->lost_samples);
7207 __output_copy(handle, values, n * sizeof(u64));
7209 for_each_sibling_event(sub, leader) {
7212 if ((sub != event) &&
7213 (sub->state == PERF_EVENT_STATE_ACTIVE))
7214 sub->pmu->read(sub);
7216 values[n++] = perf_event_count(sub);
7217 if (read_format & PERF_FORMAT_ID)
7218 values[n++] = primary_event_id(sub);
7219 if (read_format & PERF_FORMAT_LOST)
7220 values[n++] = atomic64_read(&sub->lost_samples);
7222 __output_copy(handle, values, n * sizeof(u64));
7225 local_irq_restore(flags);
7228 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
7229 PERF_FORMAT_TOTAL_TIME_RUNNING)
7232 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
7234 * The problem is that its both hard and excessively expensive to iterate the
7235 * child list, not to mention that its impossible to IPI the children running
7236 * on another CPU, from interrupt/NMI context.
7238 static void perf_output_read(struct perf_output_handle *handle,
7239 struct perf_event *event)
7241 u64 enabled = 0, running = 0, now;
7242 u64 read_format = event->attr.read_format;
7245 * compute total_time_enabled, total_time_running
7246 * based on snapshot values taken when the event
7247 * was last scheduled in.
7249 * we cannot simply called update_context_time()
7250 * because of locking issue as we are called in
7253 if (read_format & PERF_FORMAT_TOTAL_TIMES)
7254 calc_timer_values(event, &now, &enabled, &running);
7256 if (event->attr.read_format & PERF_FORMAT_GROUP)
7257 perf_output_read_group(handle, event, enabled, running);
7259 perf_output_read_one(handle, event, enabled, running);
7262 void perf_output_sample(struct perf_output_handle *handle,
7263 struct perf_event_header *header,
7264 struct perf_sample_data *data,
7265 struct perf_event *event)
7267 u64 sample_type = data->type;
7269 perf_output_put(handle, *header);
7271 if (sample_type & PERF_SAMPLE_IDENTIFIER)
7272 perf_output_put(handle, data->id);
7274 if (sample_type & PERF_SAMPLE_IP)
7275 perf_output_put(handle, data->ip);
7277 if (sample_type & PERF_SAMPLE_TID)
7278 perf_output_put(handle, data->tid_entry);
7280 if (sample_type & PERF_SAMPLE_TIME)
7281 perf_output_put(handle, data->time);
7283 if (sample_type & PERF_SAMPLE_ADDR)
7284 perf_output_put(handle, data->addr);
7286 if (sample_type & PERF_SAMPLE_ID)
7287 perf_output_put(handle, data->id);
7289 if (sample_type & PERF_SAMPLE_STREAM_ID)
7290 perf_output_put(handle, data->stream_id);
7292 if (sample_type & PERF_SAMPLE_CPU)
7293 perf_output_put(handle, data->cpu_entry);
7295 if (sample_type & PERF_SAMPLE_PERIOD)
7296 perf_output_put(handle, data->period);
7298 if (sample_type & PERF_SAMPLE_READ)
7299 perf_output_read(handle, event);
7301 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7304 size += data->callchain->nr;
7305 size *= sizeof(u64);
7306 __output_copy(handle, data->callchain, size);
7309 if (sample_type & PERF_SAMPLE_RAW) {
7310 struct perf_raw_record *raw = data->raw;
7313 struct perf_raw_frag *frag = &raw->frag;
7315 perf_output_put(handle, raw->size);
7318 __output_custom(handle, frag->copy,
7319 frag->data, frag->size);
7321 __output_copy(handle, frag->data,
7324 if (perf_raw_frag_last(frag))
7329 __output_skip(handle, NULL, frag->pad);
7335 .size = sizeof(u32),
7338 perf_output_put(handle, raw);
7342 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7343 if (data->br_stack) {
7346 size = data->br_stack->nr
7347 * sizeof(struct perf_branch_entry);
7349 perf_output_put(handle, data->br_stack->nr);
7350 if (branch_sample_hw_index(event))
7351 perf_output_put(handle, data->br_stack->hw_idx);
7352 perf_output_copy(handle, data->br_stack->entries, size);
7355 * we always store at least the value of nr
7358 perf_output_put(handle, nr);
7362 if (sample_type & PERF_SAMPLE_REGS_USER) {
7363 u64 abi = data->regs_user.abi;
7366 * If there are no regs to dump, notice it through
7367 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7369 perf_output_put(handle, abi);
7372 u64 mask = event->attr.sample_regs_user;
7373 perf_output_sample_regs(handle,
7374 data->regs_user.regs,
7379 if (sample_type & PERF_SAMPLE_STACK_USER) {
7380 perf_output_sample_ustack(handle,
7381 data->stack_user_size,
7382 data->regs_user.regs);
7385 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
7386 perf_output_put(handle, data->weight.full);
7388 if (sample_type & PERF_SAMPLE_DATA_SRC)
7389 perf_output_put(handle, data->data_src.val);
7391 if (sample_type & PERF_SAMPLE_TRANSACTION)
7392 perf_output_put(handle, data->txn);
7394 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7395 u64 abi = data->regs_intr.abi;
7397 * If there are no regs to dump, notice it through
7398 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
7400 perf_output_put(handle, abi);
7403 u64 mask = event->attr.sample_regs_intr;
7405 perf_output_sample_regs(handle,
7406 data->regs_intr.regs,
7411 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7412 perf_output_put(handle, data->phys_addr);
7414 if (sample_type & PERF_SAMPLE_CGROUP)
7415 perf_output_put(handle, data->cgroup);
7417 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7418 perf_output_put(handle, data->data_page_size);
7420 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7421 perf_output_put(handle, data->code_page_size);
7423 if (sample_type & PERF_SAMPLE_AUX) {
7424 perf_output_put(handle, data->aux_size);
7427 perf_aux_sample_output(event, handle, data);
7430 if (!event->attr.watermark) {
7431 int wakeup_events = event->attr.wakeup_events;
7433 if (wakeup_events) {
7434 struct perf_buffer *rb = handle->rb;
7435 int events = local_inc_return(&rb->events);
7437 if (events >= wakeup_events) {
7438 local_sub(wakeup_events, &rb->events);
7439 local_inc(&rb->wakeup);
7445 static u64 perf_virt_to_phys(u64 virt)
7452 if (virt >= TASK_SIZE) {
7453 /* If it's vmalloc()d memory, leave phys_addr as 0 */
7454 if (virt_addr_valid((void *)(uintptr_t)virt) &&
7455 !(virt >= VMALLOC_START && virt < VMALLOC_END))
7456 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7459 * Walking the pages tables for user address.
7460 * Interrupts are disabled, so it prevents any tear down
7461 * of the page tables.
7462 * Try IRQ-safe get_user_page_fast_only first.
7463 * If failed, leave phys_addr as 0.
7465 if (current->mm != NULL) {
7468 pagefault_disable();
7469 if (get_user_page_fast_only(virt, 0, &p)) {
7470 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7481 * Return the pagetable size of a given virtual address.
7483 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7487 #ifdef CONFIG_HAVE_FAST_GUP
7494 pgdp = pgd_offset(mm, addr);
7495 pgd = READ_ONCE(*pgdp);
7500 return pgd_leaf_size(pgd);
7502 p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7503 p4d = READ_ONCE(*p4dp);
7504 if (!p4d_present(p4d))
7508 return p4d_leaf_size(p4d);
7510 pudp = pud_offset_lockless(p4dp, p4d, addr);
7511 pud = READ_ONCE(*pudp);
7512 if (!pud_present(pud))
7516 return pud_leaf_size(pud);
7518 pmdp = pmd_offset_lockless(pudp, pud, addr);
7520 pmd = pmdp_get_lockless(pmdp);
7521 if (!pmd_present(pmd))
7525 return pmd_leaf_size(pmd);
7527 ptep = pte_offset_map(&pmd, addr);
7531 pte = ptep_get_lockless(ptep);
7532 if (pte_present(pte))
7533 size = pte_leaf_size(pte);
7535 #endif /* CONFIG_HAVE_FAST_GUP */
7540 static u64 perf_get_page_size(unsigned long addr)
7542 struct mm_struct *mm;
7543 unsigned long flags;
7550 * Software page-table walkers must disable IRQs,
7551 * which prevents any tear down of the page tables.
7553 local_irq_save(flags);
7558 * For kernel threads and the like, use init_mm so that
7559 * we can find kernel memory.
7564 size = perf_get_pgtable_size(mm, addr);
7566 local_irq_restore(flags);
7571 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7573 struct perf_callchain_entry *
7574 perf_callchain(struct perf_event *event, struct pt_regs *regs)
7576 bool kernel = !event->attr.exclude_callchain_kernel;
7577 bool user = !event->attr.exclude_callchain_user;
7578 /* Disallow cross-task user callchains. */
7579 bool crosstask = event->ctx->task && event->ctx->task != current;
7580 const u32 max_stack = event->attr.sample_max_stack;
7581 struct perf_callchain_entry *callchain;
7583 if (!kernel && !user)
7584 return &__empty_callchain;
7586 callchain = get_perf_callchain(regs, 0, kernel, user,
7587 max_stack, crosstask, true);
7588 return callchain ?: &__empty_callchain;
7591 static __always_inline u64 __cond_set(u64 flags, u64 s, u64 d)
7593 return d * !!(flags & s);
7596 void perf_prepare_sample(struct perf_sample_data *data,
7597 struct perf_event *event,
7598 struct pt_regs *regs)
7600 u64 sample_type = event->attr.sample_type;
7601 u64 filtered_sample_type;
7604 * Add the sample flags that are dependent to others. And clear the
7605 * sample flags that have already been done by the PMU driver.
7607 filtered_sample_type = sample_type;
7608 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_CODE_PAGE_SIZE,
7610 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_DATA_PAGE_SIZE |
7611 PERF_SAMPLE_PHYS_ADDR, PERF_SAMPLE_ADDR);
7612 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_STACK_USER,
7613 PERF_SAMPLE_REGS_USER);
7614 filtered_sample_type &= ~data->sample_flags;
7616 if (filtered_sample_type == 0) {
7617 /* Make sure it has the correct data->type for output */
7618 data->type = event->attr.sample_type;
7622 __perf_event_header__init_id(data, event, filtered_sample_type);
7624 if (filtered_sample_type & PERF_SAMPLE_IP) {
7625 data->ip = perf_instruction_pointer(regs);
7626 data->sample_flags |= PERF_SAMPLE_IP;
7629 if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
7630 perf_sample_save_callchain(data, event, regs);
7632 if (filtered_sample_type & PERF_SAMPLE_RAW) {
7634 data->dyn_size += sizeof(u64);
7635 data->sample_flags |= PERF_SAMPLE_RAW;
7638 if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) {
7639 data->br_stack = NULL;
7640 data->dyn_size += sizeof(u64);
7641 data->sample_flags |= PERF_SAMPLE_BRANCH_STACK;
7644 if (filtered_sample_type & PERF_SAMPLE_REGS_USER)
7645 perf_sample_regs_user(&data->regs_user, regs);
7648 * It cannot use the filtered_sample_type here as REGS_USER can be set
7649 * by STACK_USER (using __cond_set() above) and we don't want to update
7650 * the dyn_size if it's not requested by users.
7652 if ((sample_type & ~data->sample_flags) & PERF_SAMPLE_REGS_USER) {
7653 /* regs dump ABI info */
7654 int size = sizeof(u64);
7656 if (data->regs_user.regs) {
7657 u64 mask = event->attr.sample_regs_user;
7658 size += hweight64(mask) * sizeof(u64);
7661 data->dyn_size += size;
7662 data->sample_flags |= PERF_SAMPLE_REGS_USER;
7665 if (filtered_sample_type & PERF_SAMPLE_STACK_USER) {
7667 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7668 * processed as the last one or have additional check added
7669 * in case new sample type is added, because we could eat
7670 * up the rest of the sample size.
7672 u16 stack_size = event->attr.sample_stack_user;
7673 u16 header_size = perf_sample_data_size(data, event);
7674 u16 size = sizeof(u64);
7676 stack_size = perf_sample_ustack_size(stack_size, header_size,
7677 data->regs_user.regs);
7680 * If there is something to dump, add space for the dump
7681 * itself and for the field that tells the dynamic size,
7682 * which is how many have been actually dumped.
7685 size += sizeof(u64) + stack_size;
7687 data->stack_user_size = stack_size;
7688 data->dyn_size += size;
7689 data->sample_flags |= PERF_SAMPLE_STACK_USER;
7692 if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) {
7693 data->weight.full = 0;
7694 data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE;
7697 if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) {
7698 data->data_src.val = PERF_MEM_NA;
7699 data->sample_flags |= PERF_SAMPLE_DATA_SRC;
7702 if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) {
7704 data->sample_flags |= PERF_SAMPLE_TRANSACTION;
7707 if (filtered_sample_type & PERF_SAMPLE_ADDR) {
7709 data->sample_flags |= PERF_SAMPLE_ADDR;
7712 if (filtered_sample_type & PERF_SAMPLE_REGS_INTR) {
7713 /* regs dump ABI info */
7714 int size = sizeof(u64);
7716 perf_sample_regs_intr(&data->regs_intr, regs);
7718 if (data->regs_intr.regs) {
7719 u64 mask = event->attr.sample_regs_intr;
7721 size += hweight64(mask) * sizeof(u64);
7724 data->dyn_size += size;
7725 data->sample_flags |= PERF_SAMPLE_REGS_INTR;
7728 if (filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) {
7729 data->phys_addr = perf_virt_to_phys(data->addr);
7730 data->sample_flags |= PERF_SAMPLE_PHYS_ADDR;
7733 #ifdef CONFIG_CGROUP_PERF
7734 if (filtered_sample_type & PERF_SAMPLE_CGROUP) {
7735 struct cgroup *cgrp;
7737 /* protected by RCU */
7738 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7739 data->cgroup = cgroup_id(cgrp);
7740 data->sample_flags |= PERF_SAMPLE_CGROUP;
7745 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7746 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7747 * but the value will not dump to the userspace.
7749 if (filtered_sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) {
7750 data->data_page_size = perf_get_page_size(data->addr);
7751 data->sample_flags |= PERF_SAMPLE_DATA_PAGE_SIZE;
7754 if (filtered_sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) {
7755 data->code_page_size = perf_get_page_size(data->ip);
7756 data->sample_flags |= PERF_SAMPLE_CODE_PAGE_SIZE;
7759 if (filtered_sample_type & PERF_SAMPLE_AUX) {
7761 u16 header_size = perf_sample_data_size(data, event);
7763 header_size += sizeof(u64); /* size */
7766 * Given the 16bit nature of header::size, an AUX sample can
7767 * easily overflow it, what with all the preceding sample bits.
7768 * Make sure this doesn't happen by using up to U16_MAX bytes
7769 * per sample in total (rounded down to 8 byte boundary).
7771 size = min_t(size_t, U16_MAX - header_size,
7772 event->attr.aux_sample_size);
7773 size = rounddown(size, 8);
7774 size = perf_prepare_sample_aux(event, data, size);
7776 WARN_ON_ONCE(size + header_size > U16_MAX);
7777 data->dyn_size += size + sizeof(u64); /* size above */
7778 data->sample_flags |= PERF_SAMPLE_AUX;
7782 void perf_prepare_header(struct perf_event_header *header,
7783 struct perf_sample_data *data,
7784 struct perf_event *event,
7785 struct pt_regs *regs)
7787 header->type = PERF_RECORD_SAMPLE;
7788 header->size = perf_sample_data_size(data, event);
7789 header->misc = perf_misc_flags(regs);
7792 * If you're adding more sample types here, you likely need to do
7793 * something about the overflowing header::size, like repurpose the
7794 * lowest 3 bits of size, which should be always zero at the moment.
7795 * This raises a more important question, do we really need 512k sized
7796 * samples and why, so good argumentation is in order for whatever you
7799 WARN_ON_ONCE(header->size & 7);
7802 static __always_inline int
7803 __perf_event_output(struct perf_event *event,
7804 struct perf_sample_data *data,
7805 struct pt_regs *regs,
7806 int (*output_begin)(struct perf_output_handle *,
7807 struct perf_sample_data *,
7808 struct perf_event *,
7811 struct perf_output_handle handle;
7812 struct perf_event_header header;
7815 /* protect the callchain buffers */
7818 perf_prepare_sample(data, event, regs);
7819 perf_prepare_header(&header, data, event, regs);
7821 err = output_begin(&handle, data, event, header.size);
7825 perf_output_sample(&handle, &header, data, event);
7827 perf_output_end(&handle);
7835 perf_event_output_forward(struct perf_event *event,
7836 struct perf_sample_data *data,
7837 struct pt_regs *regs)
7839 __perf_event_output(event, data, regs, perf_output_begin_forward);
7843 perf_event_output_backward(struct perf_event *event,
7844 struct perf_sample_data *data,
7845 struct pt_regs *regs)
7847 __perf_event_output(event, data, regs, perf_output_begin_backward);
7851 perf_event_output(struct perf_event *event,
7852 struct perf_sample_data *data,
7853 struct pt_regs *regs)
7855 return __perf_event_output(event, data, regs, perf_output_begin);
7862 struct perf_read_event {
7863 struct perf_event_header header;
7870 perf_event_read_event(struct perf_event *event,
7871 struct task_struct *task)
7873 struct perf_output_handle handle;
7874 struct perf_sample_data sample;
7875 struct perf_read_event read_event = {
7877 .type = PERF_RECORD_READ,
7879 .size = sizeof(read_event) + event->read_size,
7881 .pid = perf_event_pid(event, task),
7882 .tid = perf_event_tid(event, task),
7886 perf_event_header__init_id(&read_event.header, &sample, event);
7887 ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7891 perf_output_put(&handle, read_event);
7892 perf_output_read(&handle, event);
7893 perf_event__output_id_sample(event, &handle, &sample);
7895 perf_output_end(&handle);
7898 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7901 perf_iterate_ctx(struct perf_event_context *ctx,
7902 perf_iterate_f output,
7903 void *data, bool all)
7905 struct perf_event *event;
7907 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7909 if (event->state < PERF_EVENT_STATE_INACTIVE)
7911 if (!event_filter_match(event))
7915 output(event, data);
7919 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7921 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7922 struct perf_event *event;
7924 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7926 * Skip events that are not fully formed yet; ensure that
7927 * if we observe event->ctx, both event and ctx will be
7928 * complete enough. See perf_install_in_context().
7930 if (!smp_load_acquire(&event->ctx))
7933 if (event->state < PERF_EVENT_STATE_INACTIVE)
7935 if (!event_filter_match(event))
7937 output(event, data);
7942 * Iterate all events that need to receive side-band events.
7944 * For new callers; ensure that account_pmu_sb_event() includes
7945 * your event, otherwise it might not get delivered.
7948 perf_iterate_sb(perf_iterate_f output, void *data,
7949 struct perf_event_context *task_ctx)
7951 struct perf_event_context *ctx;
7957 * If we have task_ctx != NULL we only notify the task context itself.
7958 * The task_ctx is set only for EXIT events before releasing task
7962 perf_iterate_ctx(task_ctx, output, data, false);
7966 perf_iterate_sb_cpu(output, data);
7968 ctx = rcu_dereference(current->perf_event_ctxp);
7970 perf_iterate_ctx(ctx, output, data, false);
7977 * Clear all file-based filters at exec, they'll have to be
7978 * re-instated when/if these objects are mmapped again.
7980 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7982 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7983 struct perf_addr_filter *filter;
7984 unsigned int restart = 0, count = 0;
7985 unsigned long flags;
7987 if (!has_addr_filter(event))
7990 raw_spin_lock_irqsave(&ifh->lock, flags);
7991 list_for_each_entry(filter, &ifh->list, entry) {
7992 if (filter->path.dentry) {
7993 event->addr_filter_ranges[count].start = 0;
7994 event->addr_filter_ranges[count].size = 0;
8002 event->addr_filters_gen++;
8003 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8006 perf_event_stop(event, 1);
8009 void perf_event_exec(void)
8011 struct perf_event_context *ctx;
8013 ctx = perf_pin_task_context(current);
8017 perf_event_enable_on_exec(ctx);
8018 perf_event_remove_on_exec(ctx);
8019 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true);
8021 perf_unpin_context(ctx);
8025 struct remote_output {
8026 struct perf_buffer *rb;
8030 static void __perf_event_output_stop(struct perf_event *event, void *data)
8032 struct perf_event *parent = event->parent;
8033 struct remote_output *ro = data;
8034 struct perf_buffer *rb = ro->rb;
8035 struct stop_event_data sd = {
8039 if (!has_aux(event))
8046 * In case of inheritance, it will be the parent that links to the
8047 * ring-buffer, but it will be the child that's actually using it.
8049 * We are using event::rb to determine if the event should be stopped,
8050 * however this may race with ring_buffer_attach() (through set_output),
8051 * which will make us skip the event that actually needs to be stopped.
8052 * So ring_buffer_attach() has to stop an aux event before re-assigning
8055 if (rcu_dereference(parent->rb) == rb)
8056 ro->err = __perf_event_stop(&sd);
8059 static int __perf_pmu_output_stop(void *info)
8061 struct perf_event *event = info;
8062 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
8063 struct remote_output ro = {
8068 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
8069 if (cpuctx->task_ctx)
8070 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
8077 static void perf_pmu_output_stop(struct perf_event *event)
8079 struct perf_event *iter;
8084 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
8086 * For per-CPU events, we need to make sure that neither they
8087 * nor their children are running; for cpu==-1 events it's
8088 * sufficient to stop the event itself if it's active, since
8089 * it can't have children.
8093 cpu = READ_ONCE(iter->oncpu);
8098 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
8099 if (err == -EAGAIN) {
8108 * task tracking -- fork/exit
8110 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
8113 struct perf_task_event {
8114 struct task_struct *task;
8115 struct perf_event_context *task_ctx;
8118 struct perf_event_header header;
8128 static int perf_event_task_match(struct perf_event *event)
8130 return event->attr.comm || event->attr.mmap ||
8131 event->attr.mmap2 || event->attr.mmap_data ||
8135 static void perf_event_task_output(struct perf_event *event,
8138 struct perf_task_event *task_event = data;
8139 struct perf_output_handle handle;
8140 struct perf_sample_data sample;
8141 struct task_struct *task = task_event->task;
8142 int ret, size = task_event->event_id.header.size;
8144 if (!perf_event_task_match(event))
8147 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
8149 ret = perf_output_begin(&handle, &sample, event,
8150 task_event->event_id.header.size);
8154 task_event->event_id.pid = perf_event_pid(event, task);
8155 task_event->event_id.tid = perf_event_tid(event, task);
8157 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
8158 task_event->event_id.ppid = perf_event_pid(event,
8160 task_event->event_id.ptid = perf_event_pid(event,
8162 } else { /* PERF_RECORD_FORK */
8163 task_event->event_id.ppid = perf_event_pid(event, current);
8164 task_event->event_id.ptid = perf_event_tid(event, current);
8167 task_event->event_id.time = perf_event_clock(event);
8169 perf_output_put(&handle, task_event->event_id);
8171 perf_event__output_id_sample(event, &handle, &sample);
8173 perf_output_end(&handle);
8175 task_event->event_id.header.size = size;
8178 static void perf_event_task(struct task_struct *task,
8179 struct perf_event_context *task_ctx,
8182 struct perf_task_event task_event;
8184 if (!atomic_read(&nr_comm_events) &&
8185 !atomic_read(&nr_mmap_events) &&
8186 !atomic_read(&nr_task_events))
8189 task_event = (struct perf_task_event){
8191 .task_ctx = task_ctx,
8194 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
8196 .size = sizeof(task_event.event_id),
8206 perf_iterate_sb(perf_event_task_output,
8211 void perf_event_fork(struct task_struct *task)
8213 perf_event_task(task, NULL, 1);
8214 perf_event_namespaces(task);
8221 struct perf_comm_event {
8222 struct task_struct *task;
8227 struct perf_event_header header;
8234 static int perf_event_comm_match(struct perf_event *event)
8236 return event->attr.comm;
8239 static void perf_event_comm_output(struct perf_event *event,
8242 struct perf_comm_event *comm_event = data;
8243 struct perf_output_handle handle;
8244 struct perf_sample_data sample;
8245 int size = comm_event->event_id.header.size;
8248 if (!perf_event_comm_match(event))
8251 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
8252 ret = perf_output_begin(&handle, &sample, event,
8253 comm_event->event_id.header.size);
8258 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
8259 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
8261 perf_output_put(&handle, comm_event->event_id);
8262 __output_copy(&handle, comm_event->comm,
8263 comm_event->comm_size);
8265 perf_event__output_id_sample(event, &handle, &sample);
8267 perf_output_end(&handle);
8269 comm_event->event_id.header.size = size;
8272 static void perf_event_comm_event(struct perf_comm_event *comm_event)
8274 char comm[TASK_COMM_LEN];
8277 memset(comm, 0, sizeof(comm));
8278 strscpy(comm, comm_event->task->comm, sizeof(comm));
8279 size = ALIGN(strlen(comm)+1, sizeof(u64));
8281 comm_event->comm = comm;
8282 comm_event->comm_size = size;
8284 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
8286 perf_iterate_sb(perf_event_comm_output,
8291 void perf_event_comm(struct task_struct *task, bool exec)
8293 struct perf_comm_event comm_event;
8295 if (!atomic_read(&nr_comm_events))
8298 comm_event = (struct perf_comm_event){
8304 .type = PERF_RECORD_COMM,
8305 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
8313 perf_event_comm_event(&comm_event);
8317 * namespaces tracking
8320 struct perf_namespaces_event {
8321 struct task_struct *task;
8324 struct perf_event_header header;
8329 struct perf_ns_link_info link_info[NR_NAMESPACES];
8333 static int perf_event_namespaces_match(struct perf_event *event)
8335 return event->attr.namespaces;
8338 static void perf_event_namespaces_output(struct perf_event *event,
8341 struct perf_namespaces_event *namespaces_event = data;
8342 struct perf_output_handle handle;
8343 struct perf_sample_data sample;
8344 u16 header_size = namespaces_event->event_id.header.size;
8347 if (!perf_event_namespaces_match(event))
8350 perf_event_header__init_id(&namespaces_event->event_id.header,
8352 ret = perf_output_begin(&handle, &sample, event,
8353 namespaces_event->event_id.header.size);
8357 namespaces_event->event_id.pid = perf_event_pid(event,
8358 namespaces_event->task);
8359 namespaces_event->event_id.tid = perf_event_tid(event,
8360 namespaces_event->task);
8362 perf_output_put(&handle, namespaces_event->event_id);
8364 perf_event__output_id_sample(event, &handle, &sample);
8366 perf_output_end(&handle);
8368 namespaces_event->event_id.header.size = header_size;
8371 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
8372 struct task_struct *task,
8373 const struct proc_ns_operations *ns_ops)
8375 struct path ns_path;
8376 struct inode *ns_inode;
8379 error = ns_get_path(&ns_path, task, ns_ops);
8381 ns_inode = ns_path.dentry->d_inode;
8382 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
8383 ns_link_info->ino = ns_inode->i_ino;
8388 void perf_event_namespaces(struct task_struct *task)
8390 struct perf_namespaces_event namespaces_event;
8391 struct perf_ns_link_info *ns_link_info;
8393 if (!atomic_read(&nr_namespaces_events))
8396 namespaces_event = (struct perf_namespaces_event){
8400 .type = PERF_RECORD_NAMESPACES,
8402 .size = sizeof(namespaces_event.event_id),
8406 .nr_namespaces = NR_NAMESPACES,
8407 /* .link_info[NR_NAMESPACES] */
8411 ns_link_info = namespaces_event.event_id.link_info;
8413 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
8414 task, &mntns_operations);
8416 #ifdef CONFIG_USER_NS
8417 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
8418 task, &userns_operations);
8420 #ifdef CONFIG_NET_NS
8421 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
8422 task, &netns_operations);
8424 #ifdef CONFIG_UTS_NS
8425 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
8426 task, &utsns_operations);
8428 #ifdef CONFIG_IPC_NS
8429 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
8430 task, &ipcns_operations);
8432 #ifdef CONFIG_PID_NS
8433 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
8434 task, &pidns_operations);
8436 #ifdef CONFIG_CGROUPS
8437 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
8438 task, &cgroupns_operations);
8441 perf_iterate_sb(perf_event_namespaces_output,
8449 #ifdef CONFIG_CGROUP_PERF
8451 struct perf_cgroup_event {
8455 struct perf_event_header header;
8461 static int perf_event_cgroup_match(struct perf_event *event)
8463 return event->attr.cgroup;
8466 static void perf_event_cgroup_output(struct perf_event *event, void *data)
8468 struct perf_cgroup_event *cgroup_event = data;
8469 struct perf_output_handle handle;
8470 struct perf_sample_data sample;
8471 u16 header_size = cgroup_event->event_id.header.size;
8474 if (!perf_event_cgroup_match(event))
8477 perf_event_header__init_id(&cgroup_event->event_id.header,
8479 ret = perf_output_begin(&handle, &sample, event,
8480 cgroup_event->event_id.header.size);
8484 perf_output_put(&handle, cgroup_event->event_id);
8485 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
8487 perf_event__output_id_sample(event, &handle, &sample);
8489 perf_output_end(&handle);
8491 cgroup_event->event_id.header.size = header_size;
8494 static void perf_event_cgroup(struct cgroup *cgrp)
8496 struct perf_cgroup_event cgroup_event;
8497 char path_enomem[16] = "//enomem";
8501 if (!atomic_read(&nr_cgroup_events))
8504 cgroup_event = (struct perf_cgroup_event){
8507 .type = PERF_RECORD_CGROUP,
8509 .size = sizeof(cgroup_event.event_id),
8511 .id = cgroup_id(cgrp),
8515 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8516 if (pathname == NULL) {
8517 cgroup_event.path = path_enomem;
8519 /* just to be sure to have enough space for alignment */
8520 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8521 cgroup_event.path = pathname;
8525 * Since our buffer works in 8 byte units we need to align our string
8526 * size to a multiple of 8. However, we must guarantee the tail end is
8527 * zero'd out to avoid leaking random bits to userspace.
8529 size = strlen(cgroup_event.path) + 1;
8530 while (!IS_ALIGNED(size, sizeof(u64)))
8531 cgroup_event.path[size++] = '\0';
8533 cgroup_event.event_id.header.size += size;
8534 cgroup_event.path_size = size;
8536 perf_iterate_sb(perf_event_cgroup_output,
8549 struct perf_mmap_event {
8550 struct vm_area_struct *vma;
8552 const char *file_name;
8558 u8 build_id[BUILD_ID_SIZE_MAX];
8562 struct perf_event_header header;
8572 static int perf_event_mmap_match(struct perf_event *event,
8575 struct perf_mmap_event *mmap_event = data;
8576 struct vm_area_struct *vma = mmap_event->vma;
8577 int executable = vma->vm_flags & VM_EXEC;
8579 return (!executable && event->attr.mmap_data) ||
8580 (executable && (event->attr.mmap || event->attr.mmap2));
8583 static void perf_event_mmap_output(struct perf_event *event,
8586 struct perf_mmap_event *mmap_event = data;
8587 struct perf_output_handle handle;
8588 struct perf_sample_data sample;
8589 int size = mmap_event->event_id.header.size;
8590 u32 type = mmap_event->event_id.header.type;
8594 if (!perf_event_mmap_match(event, data))
8597 if (event->attr.mmap2) {
8598 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8599 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8600 mmap_event->event_id.header.size += sizeof(mmap_event->min);
8601 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8602 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8603 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8604 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8607 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8608 ret = perf_output_begin(&handle, &sample, event,
8609 mmap_event->event_id.header.size);
8613 mmap_event->event_id.pid = perf_event_pid(event, current);
8614 mmap_event->event_id.tid = perf_event_tid(event, current);
8616 use_build_id = event->attr.build_id && mmap_event->build_id_size;
8618 if (event->attr.mmap2 && use_build_id)
8619 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8621 perf_output_put(&handle, mmap_event->event_id);
8623 if (event->attr.mmap2) {
8625 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8627 __output_copy(&handle, size, 4);
8628 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8630 perf_output_put(&handle, mmap_event->maj);
8631 perf_output_put(&handle, mmap_event->min);
8632 perf_output_put(&handle, mmap_event->ino);
8633 perf_output_put(&handle, mmap_event->ino_generation);
8635 perf_output_put(&handle, mmap_event->prot);
8636 perf_output_put(&handle, mmap_event->flags);
8639 __output_copy(&handle, mmap_event->file_name,
8640 mmap_event->file_size);
8642 perf_event__output_id_sample(event, &handle, &sample);
8644 perf_output_end(&handle);
8646 mmap_event->event_id.header.size = size;
8647 mmap_event->event_id.header.type = type;
8650 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8652 struct vm_area_struct *vma = mmap_event->vma;
8653 struct file *file = vma->vm_file;
8654 int maj = 0, min = 0;
8655 u64 ino = 0, gen = 0;
8656 u32 prot = 0, flags = 0;
8662 if (vma->vm_flags & VM_READ)
8664 if (vma->vm_flags & VM_WRITE)
8666 if (vma->vm_flags & VM_EXEC)
8669 if (vma->vm_flags & VM_MAYSHARE)
8672 flags = MAP_PRIVATE;
8674 if (vma->vm_flags & VM_LOCKED)
8675 flags |= MAP_LOCKED;
8676 if (is_vm_hugetlb_page(vma))
8677 flags |= MAP_HUGETLB;
8680 struct inode *inode;
8683 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8689 * d_path() works from the end of the rb backwards, so we
8690 * need to add enough zero bytes after the string to handle
8691 * the 64bit alignment we do later.
8693 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8698 inode = file_inode(vma->vm_file);
8699 dev = inode->i_sb->s_dev;
8701 gen = inode->i_generation;
8707 if (vma->vm_ops && vma->vm_ops->name)
8708 name = (char *) vma->vm_ops->name(vma);
8710 name = (char *)arch_vma_name(vma);
8712 if (vma_is_initial_heap(vma))
8714 else if (vma_is_initial_stack(vma))
8722 strscpy(tmp, name, sizeof(tmp));
8726 * Since our buffer works in 8 byte units we need to align our string
8727 * size to a multiple of 8. However, we must guarantee the tail end is
8728 * zero'd out to avoid leaking random bits to userspace.
8730 size = strlen(name)+1;
8731 while (!IS_ALIGNED(size, sizeof(u64)))
8732 name[size++] = '\0';
8734 mmap_event->file_name = name;
8735 mmap_event->file_size = size;
8736 mmap_event->maj = maj;
8737 mmap_event->min = min;
8738 mmap_event->ino = ino;
8739 mmap_event->ino_generation = gen;
8740 mmap_event->prot = prot;
8741 mmap_event->flags = flags;
8743 if (!(vma->vm_flags & VM_EXEC))
8744 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8746 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8748 if (atomic_read(&nr_build_id_events))
8749 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8751 perf_iterate_sb(perf_event_mmap_output,
8759 * Check whether inode and address range match filter criteria.
8761 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8762 struct file *file, unsigned long offset,
8765 /* d_inode(NULL) won't be equal to any mapped user-space file */
8766 if (!filter->path.dentry)
8769 if (d_inode(filter->path.dentry) != file_inode(file))
8772 if (filter->offset > offset + size)
8775 if (filter->offset + filter->size < offset)
8781 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8782 struct vm_area_struct *vma,
8783 struct perf_addr_filter_range *fr)
8785 unsigned long vma_size = vma->vm_end - vma->vm_start;
8786 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8787 struct file *file = vma->vm_file;
8789 if (!perf_addr_filter_match(filter, file, off, vma_size))
8792 if (filter->offset < off) {
8793 fr->start = vma->vm_start;
8794 fr->size = min(vma_size, filter->size - (off - filter->offset));
8796 fr->start = vma->vm_start + filter->offset - off;
8797 fr->size = min(vma->vm_end - fr->start, filter->size);
8803 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8805 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8806 struct vm_area_struct *vma = data;
8807 struct perf_addr_filter *filter;
8808 unsigned int restart = 0, count = 0;
8809 unsigned long flags;
8811 if (!has_addr_filter(event))
8817 raw_spin_lock_irqsave(&ifh->lock, flags);
8818 list_for_each_entry(filter, &ifh->list, entry) {
8819 if (perf_addr_filter_vma_adjust(filter, vma,
8820 &event->addr_filter_ranges[count]))
8827 event->addr_filters_gen++;
8828 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8831 perf_event_stop(event, 1);
8835 * Adjust all task's events' filters to the new vma
8837 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8839 struct perf_event_context *ctx;
8842 * Data tracing isn't supported yet and as such there is no need
8843 * to keep track of anything that isn't related to executable code:
8845 if (!(vma->vm_flags & VM_EXEC))
8849 ctx = rcu_dereference(current->perf_event_ctxp);
8851 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8855 void perf_event_mmap(struct vm_area_struct *vma)
8857 struct perf_mmap_event mmap_event;
8859 if (!atomic_read(&nr_mmap_events))
8862 mmap_event = (struct perf_mmap_event){
8868 .type = PERF_RECORD_MMAP,
8869 .misc = PERF_RECORD_MISC_USER,
8874 .start = vma->vm_start,
8875 .len = vma->vm_end - vma->vm_start,
8876 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8878 /* .maj (attr_mmap2 only) */
8879 /* .min (attr_mmap2 only) */
8880 /* .ino (attr_mmap2 only) */
8881 /* .ino_generation (attr_mmap2 only) */
8882 /* .prot (attr_mmap2 only) */
8883 /* .flags (attr_mmap2 only) */
8886 perf_addr_filters_adjust(vma);
8887 perf_event_mmap_event(&mmap_event);
8890 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8891 unsigned long size, u64 flags)
8893 struct perf_output_handle handle;
8894 struct perf_sample_data sample;
8895 struct perf_aux_event {
8896 struct perf_event_header header;
8902 .type = PERF_RECORD_AUX,
8904 .size = sizeof(rec),
8912 perf_event_header__init_id(&rec.header, &sample, event);
8913 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8918 perf_output_put(&handle, rec);
8919 perf_event__output_id_sample(event, &handle, &sample);
8921 perf_output_end(&handle);
8925 * Lost/dropped samples logging
8927 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8929 struct perf_output_handle handle;
8930 struct perf_sample_data sample;
8934 struct perf_event_header header;
8936 } lost_samples_event = {
8938 .type = PERF_RECORD_LOST_SAMPLES,
8940 .size = sizeof(lost_samples_event),
8945 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8947 ret = perf_output_begin(&handle, &sample, event,
8948 lost_samples_event.header.size);
8952 perf_output_put(&handle, lost_samples_event);
8953 perf_event__output_id_sample(event, &handle, &sample);
8954 perf_output_end(&handle);
8958 * context_switch tracking
8961 struct perf_switch_event {
8962 struct task_struct *task;
8963 struct task_struct *next_prev;
8966 struct perf_event_header header;
8972 static int perf_event_switch_match(struct perf_event *event)
8974 return event->attr.context_switch;
8977 static void perf_event_switch_output(struct perf_event *event, void *data)
8979 struct perf_switch_event *se = data;
8980 struct perf_output_handle handle;
8981 struct perf_sample_data sample;
8984 if (!perf_event_switch_match(event))
8987 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8988 if (event->ctx->task) {
8989 se->event_id.header.type = PERF_RECORD_SWITCH;
8990 se->event_id.header.size = sizeof(se->event_id.header);
8992 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8993 se->event_id.header.size = sizeof(se->event_id);
8994 se->event_id.next_prev_pid =
8995 perf_event_pid(event, se->next_prev);
8996 se->event_id.next_prev_tid =
8997 perf_event_tid(event, se->next_prev);
9000 perf_event_header__init_id(&se->event_id.header, &sample, event);
9002 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
9006 if (event->ctx->task)
9007 perf_output_put(&handle, se->event_id.header);
9009 perf_output_put(&handle, se->event_id);
9011 perf_event__output_id_sample(event, &handle, &sample);
9013 perf_output_end(&handle);
9016 static void perf_event_switch(struct task_struct *task,
9017 struct task_struct *next_prev, bool sched_in)
9019 struct perf_switch_event switch_event;
9021 /* N.B. caller checks nr_switch_events != 0 */
9023 switch_event = (struct perf_switch_event){
9025 .next_prev = next_prev,
9029 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
9032 /* .next_prev_pid */
9033 /* .next_prev_tid */
9037 if (!sched_in && task->on_rq) {
9038 switch_event.event_id.header.misc |=
9039 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
9042 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL);
9046 * IRQ throttle logging
9049 static void perf_log_throttle(struct perf_event *event, int enable)
9051 struct perf_output_handle handle;
9052 struct perf_sample_data sample;
9056 struct perf_event_header header;
9060 } throttle_event = {
9062 .type = PERF_RECORD_THROTTLE,
9064 .size = sizeof(throttle_event),
9066 .time = perf_event_clock(event),
9067 .id = primary_event_id(event),
9068 .stream_id = event->id,
9072 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
9074 perf_event_header__init_id(&throttle_event.header, &sample, event);
9076 ret = perf_output_begin(&handle, &sample, event,
9077 throttle_event.header.size);
9081 perf_output_put(&handle, throttle_event);
9082 perf_event__output_id_sample(event, &handle, &sample);
9083 perf_output_end(&handle);
9087 * ksymbol register/unregister tracking
9090 struct perf_ksymbol_event {
9094 struct perf_event_header header;
9102 static int perf_event_ksymbol_match(struct perf_event *event)
9104 return event->attr.ksymbol;
9107 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
9109 struct perf_ksymbol_event *ksymbol_event = data;
9110 struct perf_output_handle handle;
9111 struct perf_sample_data sample;
9114 if (!perf_event_ksymbol_match(event))
9117 perf_event_header__init_id(&ksymbol_event->event_id.header,
9119 ret = perf_output_begin(&handle, &sample, event,
9120 ksymbol_event->event_id.header.size);
9124 perf_output_put(&handle, ksymbol_event->event_id);
9125 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
9126 perf_event__output_id_sample(event, &handle, &sample);
9128 perf_output_end(&handle);
9131 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
9134 struct perf_ksymbol_event ksymbol_event;
9135 char name[KSYM_NAME_LEN];
9139 if (!atomic_read(&nr_ksymbol_events))
9142 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
9143 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
9146 strscpy(name, sym, KSYM_NAME_LEN);
9147 name_len = strlen(name) + 1;
9148 while (!IS_ALIGNED(name_len, sizeof(u64)))
9149 name[name_len++] = '\0';
9150 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
9153 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
9155 ksymbol_event = (struct perf_ksymbol_event){
9157 .name_len = name_len,
9160 .type = PERF_RECORD_KSYMBOL,
9161 .size = sizeof(ksymbol_event.event_id) +
9166 .ksym_type = ksym_type,
9171 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
9174 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
9178 * bpf program load/unload tracking
9181 struct perf_bpf_event {
9182 struct bpf_prog *prog;
9184 struct perf_event_header header;
9188 u8 tag[BPF_TAG_SIZE];
9192 static int perf_event_bpf_match(struct perf_event *event)
9194 return event->attr.bpf_event;
9197 static void perf_event_bpf_output(struct perf_event *event, void *data)
9199 struct perf_bpf_event *bpf_event = data;
9200 struct perf_output_handle handle;
9201 struct perf_sample_data sample;
9204 if (!perf_event_bpf_match(event))
9207 perf_event_header__init_id(&bpf_event->event_id.header,
9209 ret = perf_output_begin(&handle, &sample, event,
9210 bpf_event->event_id.header.size);
9214 perf_output_put(&handle, bpf_event->event_id);
9215 perf_event__output_id_sample(event, &handle, &sample);
9217 perf_output_end(&handle);
9220 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
9221 enum perf_bpf_event_type type)
9223 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
9226 if (prog->aux->func_cnt == 0) {
9227 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
9228 (u64)(unsigned long)prog->bpf_func,
9229 prog->jited_len, unregister,
9230 prog->aux->ksym.name);
9232 for (i = 0; i < prog->aux->func_cnt; i++) {
9233 struct bpf_prog *subprog = prog->aux->func[i];
9236 PERF_RECORD_KSYMBOL_TYPE_BPF,
9237 (u64)(unsigned long)subprog->bpf_func,
9238 subprog->jited_len, unregister,
9239 subprog->aux->ksym.name);
9244 void perf_event_bpf_event(struct bpf_prog *prog,
9245 enum perf_bpf_event_type type,
9248 struct perf_bpf_event bpf_event;
9250 if (type <= PERF_BPF_EVENT_UNKNOWN ||
9251 type >= PERF_BPF_EVENT_MAX)
9255 case PERF_BPF_EVENT_PROG_LOAD:
9256 case PERF_BPF_EVENT_PROG_UNLOAD:
9257 if (atomic_read(&nr_ksymbol_events))
9258 perf_event_bpf_emit_ksymbols(prog, type);
9264 if (!atomic_read(&nr_bpf_events))
9267 bpf_event = (struct perf_bpf_event){
9271 .type = PERF_RECORD_BPF_EVENT,
9272 .size = sizeof(bpf_event.event_id),
9276 .id = prog->aux->id,
9280 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
9282 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
9283 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
9286 struct perf_text_poke_event {
9287 const void *old_bytes;
9288 const void *new_bytes;
9294 struct perf_event_header header;
9300 static int perf_event_text_poke_match(struct perf_event *event)
9302 return event->attr.text_poke;
9305 static void perf_event_text_poke_output(struct perf_event *event, void *data)
9307 struct perf_text_poke_event *text_poke_event = data;
9308 struct perf_output_handle handle;
9309 struct perf_sample_data sample;
9313 if (!perf_event_text_poke_match(event))
9316 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
9318 ret = perf_output_begin(&handle, &sample, event,
9319 text_poke_event->event_id.header.size);
9323 perf_output_put(&handle, text_poke_event->event_id);
9324 perf_output_put(&handle, text_poke_event->old_len);
9325 perf_output_put(&handle, text_poke_event->new_len);
9327 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
9328 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
9330 if (text_poke_event->pad)
9331 __output_copy(&handle, &padding, text_poke_event->pad);
9333 perf_event__output_id_sample(event, &handle, &sample);
9335 perf_output_end(&handle);
9338 void perf_event_text_poke(const void *addr, const void *old_bytes,
9339 size_t old_len, const void *new_bytes, size_t new_len)
9341 struct perf_text_poke_event text_poke_event;
9344 if (!atomic_read(&nr_text_poke_events))
9347 tot = sizeof(text_poke_event.old_len) + old_len;
9348 tot += sizeof(text_poke_event.new_len) + new_len;
9349 pad = ALIGN(tot, sizeof(u64)) - tot;
9351 text_poke_event = (struct perf_text_poke_event){
9352 .old_bytes = old_bytes,
9353 .new_bytes = new_bytes,
9359 .type = PERF_RECORD_TEXT_POKE,
9360 .misc = PERF_RECORD_MISC_KERNEL,
9361 .size = sizeof(text_poke_event.event_id) + tot + pad,
9363 .addr = (unsigned long)addr,
9367 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
9370 void perf_event_itrace_started(struct perf_event *event)
9372 event->attach_state |= PERF_ATTACH_ITRACE;
9375 static void perf_log_itrace_start(struct perf_event *event)
9377 struct perf_output_handle handle;
9378 struct perf_sample_data sample;
9379 struct perf_aux_event {
9380 struct perf_event_header header;
9387 event = event->parent;
9389 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
9390 event->attach_state & PERF_ATTACH_ITRACE)
9393 rec.header.type = PERF_RECORD_ITRACE_START;
9394 rec.header.misc = 0;
9395 rec.header.size = sizeof(rec);
9396 rec.pid = perf_event_pid(event, current);
9397 rec.tid = perf_event_tid(event, current);
9399 perf_event_header__init_id(&rec.header, &sample, event);
9400 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9405 perf_output_put(&handle, rec);
9406 perf_event__output_id_sample(event, &handle, &sample);
9408 perf_output_end(&handle);
9411 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
9413 struct perf_output_handle handle;
9414 struct perf_sample_data sample;
9415 struct perf_aux_event {
9416 struct perf_event_header header;
9422 event = event->parent;
9424 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID;
9425 rec.header.misc = 0;
9426 rec.header.size = sizeof(rec);
9429 perf_event_header__init_id(&rec.header, &sample, event);
9430 ret = perf_output_begin(&handle, &sample, event, rec.header.size);
9435 perf_output_put(&handle, rec);
9436 perf_event__output_id_sample(event, &handle, &sample);
9438 perf_output_end(&handle);
9440 EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
9443 __perf_event_account_interrupt(struct perf_event *event, int throttle)
9445 struct hw_perf_event *hwc = &event->hw;
9449 seq = __this_cpu_read(perf_throttled_seq);
9450 if (seq != hwc->interrupts_seq) {
9451 hwc->interrupts_seq = seq;
9452 hwc->interrupts = 1;
9455 if (unlikely(throttle &&
9456 hwc->interrupts > max_samples_per_tick)) {
9457 __this_cpu_inc(perf_throttled_count);
9458 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
9459 hwc->interrupts = MAX_INTERRUPTS;
9460 perf_log_throttle(event, 0);
9465 if (event->attr.freq) {
9466 u64 now = perf_clock();
9467 s64 delta = now - hwc->freq_time_stamp;
9469 hwc->freq_time_stamp = now;
9471 if (delta > 0 && delta < 2*TICK_NSEC)
9472 perf_adjust_period(event, delta, hwc->last_period, true);
9478 int perf_event_account_interrupt(struct perf_event *event)
9480 return __perf_event_account_interrupt(event, 1);
9483 static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs)
9486 * Due to interrupt latency (AKA "skid"), we may enter the
9487 * kernel before taking an overflow, even if the PMU is only
9488 * counting user events.
9490 if (event->attr.exclude_kernel && !user_mode(regs))
9497 * Generic event overflow handling, sampling.
9500 static int __perf_event_overflow(struct perf_event *event,
9501 int throttle, struct perf_sample_data *data,
9502 struct pt_regs *regs)
9504 int events = atomic_read(&event->event_limit);
9508 * Non-sampling counters might still use the PMI to fold short
9509 * hardware counters, ignore those.
9511 if (unlikely(!is_sampling_event(event)))
9514 ret = __perf_event_account_interrupt(event, throttle);
9517 * XXX event_limit might not quite work as expected on inherited
9521 event->pending_kill = POLL_IN;
9522 if (events && atomic_dec_and_test(&event->event_limit)) {
9524 event->pending_kill = POLL_HUP;
9525 perf_event_disable_inatomic(event);
9528 if (event->attr.sigtrap) {
9530 * The desired behaviour of sigtrap vs invalid samples is a bit
9531 * tricky; on the one hand, one should not loose the SIGTRAP if
9532 * it is the first event, on the other hand, we should also not
9533 * trigger the WARN or override the data address.
9535 bool valid_sample = sample_is_allowed(event, regs);
9536 unsigned int pending_id = 1;
9539 pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1;
9540 if (!event->pending_sigtrap) {
9541 event->pending_sigtrap = pending_id;
9542 local_inc(&event->ctx->nr_pending);
9543 } else if (event->attr.exclude_kernel && valid_sample) {
9545 * Should not be able to return to user space without
9546 * consuming pending_sigtrap; with exceptions:
9548 * 1. Where !exclude_kernel, events can overflow again
9549 * in the kernel without returning to user space.
9551 * 2. Events that can overflow again before the IRQ-
9552 * work without user space progress (e.g. hrtimer).
9553 * To approximate progress (with false negatives),
9554 * check 32-bit hash of the current IP.
9556 WARN_ON_ONCE(event->pending_sigtrap != pending_id);
9559 event->pending_addr = 0;
9560 if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
9561 event->pending_addr = data->addr;
9562 irq_work_queue(&event->pending_irq);
9565 READ_ONCE(event->overflow_handler)(event, data, regs);
9567 if (*perf_event_fasync(event) && event->pending_kill) {
9568 event->pending_wakeup = 1;
9569 irq_work_queue(&event->pending_irq);
9575 int perf_event_overflow(struct perf_event *event,
9576 struct perf_sample_data *data,
9577 struct pt_regs *regs)
9579 return __perf_event_overflow(event, 1, data, regs);
9583 * Generic software event infrastructure
9586 struct swevent_htable {
9587 struct swevent_hlist *swevent_hlist;
9588 struct mutex hlist_mutex;
9591 /* Recursion avoidance in each contexts */
9592 int recursion[PERF_NR_CONTEXTS];
9595 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9598 * We directly increment event->count and keep a second value in
9599 * event->hw.period_left to count intervals. This period event
9600 * is kept in the range [-sample_period, 0] so that we can use the
9604 u64 perf_swevent_set_period(struct perf_event *event)
9606 struct hw_perf_event *hwc = &event->hw;
9607 u64 period = hwc->last_period;
9611 hwc->last_period = hwc->sample_period;
9613 old = local64_read(&hwc->period_left);
9619 nr = div64_u64(period + val, period);
9620 offset = nr * period;
9622 } while (!local64_try_cmpxchg(&hwc->period_left, &old, val));
9627 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9628 struct perf_sample_data *data,
9629 struct pt_regs *regs)
9631 struct hw_perf_event *hwc = &event->hw;
9635 overflow = perf_swevent_set_period(event);
9637 if (hwc->interrupts == MAX_INTERRUPTS)
9640 for (; overflow; overflow--) {
9641 if (__perf_event_overflow(event, throttle,
9644 * We inhibit the overflow from happening when
9645 * hwc->interrupts == MAX_INTERRUPTS.
9653 static void perf_swevent_event(struct perf_event *event, u64 nr,
9654 struct perf_sample_data *data,
9655 struct pt_regs *regs)
9657 struct hw_perf_event *hwc = &event->hw;
9659 local64_add(nr, &event->count);
9664 if (!is_sampling_event(event))
9667 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9669 return perf_swevent_overflow(event, 1, data, regs);
9671 data->period = event->hw.last_period;
9673 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9674 return perf_swevent_overflow(event, 1, data, regs);
9676 if (local64_add_negative(nr, &hwc->period_left))
9679 perf_swevent_overflow(event, 0, data, regs);
9682 static int perf_exclude_event(struct perf_event *event,
9683 struct pt_regs *regs)
9685 if (event->hw.state & PERF_HES_STOPPED)
9689 if (event->attr.exclude_user && user_mode(regs))
9692 if (event->attr.exclude_kernel && !user_mode(regs))
9699 static int perf_swevent_match(struct perf_event *event,
9700 enum perf_type_id type,
9702 struct perf_sample_data *data,
9703 struct pt_regs *regs)
9705 if (event->attr.type != type)
9708 if (event->attr.config != event_id)
9711 if (perf_exclude_event(event, regs))
9717 static inline u64 swevent_hash(u64 type, u32 event_id)
9719 u64 val = event_id | (type << 32);
9721 return hash_64(val, SWEVENT_HLIST_BITS);
9724 static inline struct hlist_head *
9725 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9727 u64 hash = swevent_hash(type, event_id);
9729 return &hlist->heads[hash];
9732 /* For the read side: events when they trigger */
9733 static inline struct hlist_head *
9734 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9736 struct swevent_hlist *hlist;
9738 hlist = rcu_dereference(swhash->swevent_hlist);
9742 return __find_swevent_head(hlist, type, event_id);
9745 /* For the event head insertion and removal in the hlist */
9746 static inline struct hlist_head *
9747 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9749 struct swevent_hlist *hlist;
9750 u32 event_id = event->attr.config;
9751 u64 type = event->attr.type;
9754 * Event scheduling is always serialized against hlist allocation
9755 * and release. Which makes the protected version suitable here.
9756 * The context lock guarantees that.
9758 hlist = rcu_dereference_protected(swhash->swevent_hlist,
9759 lockdep_is_held(&event->ctx->lock));
9763 return __find_swevent_head(hlist, type, event_id);
9766 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9768 struct perf_sample_data *data,
9769 struct pt_regs *regs)
9771 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9772 struct perf_event *event;
9773 struct hlist_head *head;
9776 head = find_swevent_head_rcu(swhash, type, event_id);
9780 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9781 if (perf_swevent_match(event, type, event_id, data, regs))
9782 perf_swevent_event(event, nr, data, regs);
9788 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9790 int perf_swevent_get_recursion_context(void)
9792 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9794 return get_recursion_context(swhash->recursion);
9796 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9798 void perf_swevent_put_recursion_context(int rctx)
9800 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9802 put_recursion_context(swhash->recursion, rctx);
9805 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9807 struct perf_sample_data data;
9809 if (WARN_ON_ONCE(!regs))
9812 perf_sample_data_init(&data, addr, 0);
9813 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9816 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9820 preempt_disable_notrace();
9821 rctx = perf_swevent_get_recursion_context();
9822 if (unlikely(rctx < 0))
9825 ___perf_sw_event(event_id, nr, regs, addr);
9827 perf_swevent_put_recursion_context(rctx);
9829 preempt_enable_notrace();
9832 static void perf_swevent_read(struct perf_event *event)
9836 static int perf_swevent_add(struct perf_event *event, int flags)
9838 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9839 struct hw_perf_event *hwc = &event->hw;
9840 struct hlist_head *head;
9842 if (is_sampling_event(event)) {
9843 hwc->last_period = hwc->sample_period;
9844 perf_swevent_set_period(event);
9847 hwc->state = !(flags & PERF_EF_START);
9849 head = find_swevent_head(swhash, event);
9850 if (WARN_ON_ONCE(!head))
9853 hlist_add_head_rcu(&event->hlist_entry, head);
9854 perf_event_update_userpage(event);
9859 static void perf_swevent_del(struct perf_event *event, int flags)
9861 hlist_del_rcu(&event->hlist_entry);
9864 static void perf_swevent_start(struct perf_event *event, int flags)
9866 event->hw.state = 0;
9869 static void perf_swevent_stop(struct perf_event *event, int flags)
9871 event->hw.state = PERF_HES_STOPPED;
9874 /* Deref the hlist from the update side */
9875 static inline struct swevent_hlist *
9876 swevent_hlist_deref(struct swevent_htable *swhash)
9878 return rcu_dereference_protected(swhash->swevent_hlist,
9879 lockdep_is_held(&swhash->hlist_mutex));
9882 static void swevent_hlist_release(struct swevent_htable *swhash)
9884 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9889 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9890 kfree_rcu(hlist, rcu_head);
9893 static void swevent_hlist_put_cpu(int cpu)
9895 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9897 mutex_lock(&swhash->hlist_mutex);
9899 if (!--swhash->hlist_refcount)
9900 swevent_hlist_release(swhash);
9902 mutex_unlock(&swhash->hlist_mutex);
9905 static void swevent_hlist_put(void)
9909 for_each_possible_cpu(cpu)
9910 swevent_hlist_put_cpu(cpu);
9913 static int swevent_hlist_get_cpu(int cpu)
9915 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9918 mutex_lock(&swhash->hlist_mutex);
9919 if (!swevent_hlist_deref(swhash) &&
9920 cpumask_test_cpu(cpu, perf_online_mask)) {
9921 struct swevent_hlist *hlist;
9923 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9928 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9930 swhash->hlist_refcount++;
9932 mutex_unlock(&swhash->hlist_mutex);
9937 static int swevent_hlist_get(void)
9939 int err, cpu, failed_cpu;
9941 mutex_lock(&pmus_lock);
9942 for_each_possible_cpu(cpu) {
9943 err = swevent_hlist_get_cpu(cpu);
9949 mutex_unlock(&pmus_lock);
9952 for_each_possible_cpu(cpu) {
9953 if (cpu == failed_cpu)
9955 swevent_hlist_put_cpu(cpu);
9957 mutex_unlock(&pmus_lock);
9961 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9963 static void sw_perf_event_destroy(struct perf_event *event)
9965 u64 event_id = event->attr.config;
9967 WARN_ON(event->parent);
9969 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9970 swevent_hlist_put();
9973 static struct pmu perf_cpu_clock; /* fwd declaration */
9974 static struct pmu perf_task_clock;
9976 static int perf_swevent_init(struct perf_event *event)
9978 u64 event_id = event->attr.config;
9980 if (event->attr.type != PERF_TYPE_SOFTWARE)
9984 * no branch sampling for software events
9986 if (has_branch_stack(event))
9990 case PERF_COUNT_SW_CPU_CLOCK:
9991 event->attr.type = perf_cpu_clock.type;
9993 case PERF_COUNT_SW_TASK_CLOCK:
9994 event->attr.type = perf_task_clock.type;
10001 if (event_id >= PERF_COUNT_SW_MAX)
10004 if (!event->parent) {
10007 err = swevent_hlist_get();
10011 static_key_slow_inc(&perf_swevent_enabled[event_id]);
10012 event->destroy = sw_perf_event_destroy;
10018 static struct pmu perf_swevent = {
10019 .task_ctx_nr = perf_sw_context,
10021 .capabilities = PERF_PMU_CAP_NO_NMI,
10023 .event_init = perf_swevent_init,
10024 .add = perf_swevent_add,
10025 .del = perf_swevent_del,
10026 .start = perf_swevent_start,
10027 .stop = perf_swevent_stop,
10028 .read = perf_swevent_read,
10031 #ifdef CONFIG_EVENT_TRACING
10033 static void tp_perf_event_destroy(struct perf_event *event)
10035 perf_trace_destroy(event);
10038 static int perf_tp_event_init(struct perf_event *event)
10042 if (event->attr.type != PERF_TYPE_TRACEPOINT)
10046 * no branch sampling for tracepoint events
10048 if (has_branch_stack(event))
10049 return -EOPNOTSUPP;
10051 err = perf_trace_init(event);
10055 event->destroy = tp_perf_event_destroy;
10060 static struct pmu perf_tracepoint = {
10061 .task_ctx_nr = perf_sw_context,
10063 .event_init = perf_tp_event_init,
10064 .add = perf_trace_add,
10065 .del = perf_trace_del,
10066 .start = perf_swevent_start,
10067 .stop = perf_swevent_stop,
10068 .read = perf_swevent_read,
10071 static int perf_tp_filter_match(struct perf_event *event,
10072 struct perf_sample_data *data)
10074 void *record = data->raw->frag.data;
10076 /* only top level events have filters set */
10078 event = event->parent;
10080 if (likely(!event->filter) || filter_match_preds(event->filter, record))
10085 static int perf_tp_event_match(struct perf_event *event,
10086 struct perf_sample_data *data,
10087 struct pt_regs *regs)
10089 if (event->hw.state & PERF_HES_STOPPED)
10092 * If exclude_kernel, only trace user-space tracepoints (uprobes)
10094 if (event->attr.exclude_kernel && !user_mode(regs))
10097 if (!perf_tp_filter_match(event, data))
10103 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
10104 struct trace_event_call *call, u64 count,
10105 struct pt_regs *regs, struct hlist_head *head,
10106 struct task_struct *task)
10108 if (bpf_prog_array_valid(call)) {
10109 *(struct pt_regs **)raw_data = regs;
10110 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
10111 perf_swevent_put_recursion_context(rctx);
10115 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
10118 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
10120 static void __perf_tp_event_target_task(u64 count, void *record,
10121 struct pt_regs *regs,
10122 struct perf_sample_data *data,
10123 struct perf_event *event)
10125 struct trace_entry *entry = record;
10127 if (event->attr.config != entry->type)
10129 /* Cannot deliver synchronous signal to other task. */
10130 if (event->attr.sigtrap)
10132 if (perf_tp_event_match(event, data, regs))
10133 perf_swevent_event(event, count, data, regs);
10136 static void perf_tp_event_target_task(u64 count, void *record,
10137 struct pt_regs *regs,
10138 struct perf_sample_data *data,
10139 struct perf_event_context *ctx)
10141 unsigned int cpu = smp_processor_id();
10142 struct pmu *pmu = &perf_tracepoint;
10143 struct perf_event *event, *sibling;
10145 perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) {
10146 __perf_tp_event_target_task(count, record, regs, data, event);
10147 for_each_sibling_event(sibling, event)
10148 __perf_tp_event_target_task(count, record, regs, data, sibling);
10151 perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) {
10152 __perf_tp_event_target_task(count, record, regs, data, event);
10153 for_each_sibling_event(sibling, event)
10154 __perf_tp_event_target_task(count, record, regs, data, sibling);
10158 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
10159 struct pt_regs *regs, struct hlist_head *head, int rctx,
10160 struct task_struct *task)
10162 struct perf_sample_data data;
10163 struct perf_event *event;
10165 struct perf_raw_record raw = {
10167 .size = entry_size,
10172 perf_sample_data_init(&data, 0, 0);
10173 perf_sample_save_raw_data(&data, &raw);
10175 perf_trace_buf_update(record, event_type);
10177 hlist_for_each_entry_rcu(event, head, hlist_entry) {
10178 if (perf_tp_event_match(event, &data, regs)) {
10179 perf_swevent_event(event, count, &data, regs);
10182 * Here use the same on-stack perf_sample_data,
10183 * some members in data are event-specific and
10184 * need to be re-computed for different sweveents.
10185 * Re-initialize data->sample_flags safely to avoid
10186 * the problem that next event skips preparing data
10187 * because data->sample_flags is set.
10189 perf_sample_data_init(&data, 0, 0);
10190 perf_sample_save_raw_data(&data, &raw);
10195 * If we got specified a target task, also iterate its context and
10196 * deliver this event there too.
10198 if (task && task != current) {
10199 struct perf_event_context *ctx;
10202 ctx = rcu_dereference(task->perf_event_ctxp);
10206 raw_spin_lock(&ctx->lock);
10207 perf_tp_event_target_task(count, record, regs, &data, ctx);
10208 raw_spin_unlock(&ctx->lock);
10213 perf_swevent_put_recursion_context(rctx);
10215 EXPORT_SYMBOL_GPL(perf_tp_event);
10217 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
10219 * Flags in config, used by dynamic PMU kprobe and uprobe
10220 * The flags should match following PMU_FORMAT_ATTR().
10222 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
10223 * if not set, create kprobe/uprobe
10225 * The following values specify a reference counter (or semaphore in the
10226 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
10227 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
10229 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
10230 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
10232 enum perf_probe_config {
10233 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
10234 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
10235 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
10238 PMU_FORMAT_ATTR(retprobe, "config:0");
10241 #ifdef CONFIG_KPROBE_EVENTS
10242 static struct attribute *kprobe_attrs[] = {
10243 &format_attr_retprobe.attr,
10247 static struct attribute_group kprobe_format_group = {
10249 .attrs = kprobe_attrs,
10252 static const struct attribute_group *kprobe_attr_groups[] = {
10253 &kprobe_format_group,
10257 static int perf_kprobe_event_init(struct perf_event *event);
10258 static struct pmu perf_kprobe = {
10259 .task_ctx_nr = perf_sw_context,
10260 .event_init = perf_kprobe_event_init,
10261 .add = perf_trace_add,
10262 .del = perf_trace_del,
10263 .start = perf_swevent_start,
10264 .stop = perf_swevent_stop,
10265 .read = perf_swevent_read,
10266 .attr_groups = kprobe_attr_groups,
10269 static int perf_kprobe_event_init(struct perf_event *event)
10274 if (event->attr.type != perf_kprobe.type)
10277 if (!perfmon_capable())
10281 * no branch sampling for probe events
10283 if (has_branch_stack(event))
10284 return -EOPNOTSUPP;
10286 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10287 err = perf_kprobe_init(event, is_retprobe);
10291 event->destroy = perf_kprobe_destroy;
10295 #endif /* CONFIG_KPROBE_EVENTS */
10297 #ifdef CONFIG_UPROBE_EVENTS
10298 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
10300 static struct attribute *uprobe_attrs[] = {
10301 &format_attr_retprobe.attr,
10302 &format_attr_ref_ctr_offset.attr,
10306 static struct attribute_group uprobe_format_group = {
10308 .attrs = uprobe_attrs,
10311 static const struct attribute_group *uprobe_attr_groups[] = {
10312 &uprobe_format_group,
10316 static int perf_uprobe_event_init(struct perf_event *event);
10317 static struct pmu perf_uprobe = {
10318 .task_ctx_nr = perf_sw_context,
10319 .event_init = perf_uprobe_event_init,
10320 .add = perf_trace_add,
10321 .del = perf_trace_del,
10322 .start = perf_swevent_start,
10323 .stop = perf_swevent_stop,
10324 .read = perf_swevent_read,
10325 .attr_groups = uprobe_attr_groups,
10328 static int perf_uprobe_event_init(struct perf_event *event)
10331 unsigned long ref_ctr_offset;
10334 if (event->attr.type != perf_uprobe.type)
10337 if (!perfmon_capable())
10341 * no branch sampling for probe events
10343 if (has_branch_stack(event))
10344 return -EOPNOTSUPP;
10346 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
10347 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
10348 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
10352 event->destroy = perf_uprobe_destroy;
10356 #endif /* CONFIG_UPROBE_EVENTS */
10358 static inline void perf_tp_register(void)
10360 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
10361 #ifdef CONFIG_KPROBE_EVENTS
10362 perf_pmu_register(&perf_kprobe, "kprobe", -1);
10364 #ifdef CONFIG_UPROBE_EVENTS
10365 perf_pmu_register(&perf_uprobe, "uprobe", -1);
10369 static void perf_event_free_filter(struct perf_event *event)
10371 ftrace_profile_free_filter(event);
10374 #ifdef CONFIG_BPF_SYSCALL
10375 static void bpf_overflow_handler(struct perf_event *event,
10376 struct perf_sample_data *data,
10377 struct pt_regs *regs)
10379 struct bpf_perf_event_data_kern ctx = {
10383 struct bpf_prog *prog;
10386 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
10387 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
10390 prog = READ_ONCE(event->prog);
10392 perf_prepare_sample(data, event, regs);
10393 ret = bpf_prog_run(prog, &ctx);
10397 __this_cpu_dec(bpf_prog_active);
10401 event->orig_overflow_handler(event, data, regs);
10404 static int perf_event_set_bpf_handler(struct perf_event *event,
10405 struct bpf_prog *prog,
10408 if (event->overflow_handler_context)
10409 /* hw breakpoint or kernel counter */
10415 if (prog->type != BPF_PROG_TYPE_PERF_EVENT)
10418 if (event->attr.precise_ip &&
10419 prog->call_get_stack &&
10420 (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
10421 event->attr.exclude_callchain_kernel ||
10422 event->attr.exclude_callchain_user)) {
10424 * On perf_event with precise_ip, calling bpf_get_stack()
10425 * may trigger unwinder warnings and occasional crashes.
10426 * bpf_get_[stack|stackid] works around this issue by using
10427 * callchain attached to perf_sample_data. If the
10428 * perf_event does not full (kernel and user) callchain
10429 * attached to perf_sample_data, do not allow attaching BPF
10430 * program that calls bpf_get_[stack|stackid].
10435 event->prog = prog;
10436 event->bpf_cookie = bpf_cookie;
10437 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
10438 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
10442 static void perf_event_free_bpf_handler(struct perf_event *event)
10444 struct bpf_prog *prog = event->prog;
10449 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
10450 event->prog = NULL;
10451 bpf_prog_put(prog);
10454 static int perf_event_set_bpf_handler(struct perf_event *event,
10455 struct bpf_prog *prog,
10458 return -EOPNOTSUPP;
10460 static void perf_event_free_bpf_handler(struct perf_event *event)
10466 * returns true if the event is a tracepoint, or a kprobe/upprobe created
10467 * with perf_event_open()
10469 static inline bool perf_event_is_tracing(struct perf_event *event)
10471 if (event->pmu == &perf_tracepoint)
10473 #ifdef CONFIG_KPROBE_EVENTS
10474 if (event->pmu == &perf_kprobe)
10477 #ifdef CONFIG_UPROBE_EVENTS
10478 if (event->pmu == &perf_uprobe)
10484 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10487 bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp;
10489 if (!perf_event_is_tracing(event))
10490 return perf_event_set_bpf_handler(event, prog, bpf_cookie);
10492 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE;
10493 is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE;
10494 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
10495 is_syscall_tp = is_syscall_trace_event(event->tp_event);
10496 if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp)
10497 /* bpf programs can only be attached to u/kprobe or tracepoint */
10500 if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) ||
10501 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
10502 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT))
10505 if (prog->type == BPF_PROG_TYPE_KPROBE && prog->aux->sleepable && !is_uprobe)
10506 /* only uprobe programs are allowed to be sleepable */
10509 /* Kprobe override only works for kprobes, not uprobes. */
10510 if (prog->kprobe_override && !is_kprobe)
10513 if (is_tracepoint || is_syscall_tp) {
10514 int off = trace_event_get_offsets(event->tp_event);
10516 if (prog->aux->max_ctx_offset > off)
10520 return perf_event_attach_bpf_prog(event, prog, bpf_cookie);
10523 void perf_event_free_bpf_prog(struct perf_event *event)
10525 if (!perf_event_is_tracing(event)) {
10526 perf_event_free_bpf_handler(event);
10529 perf_event_detach_bpf_prog(event);
10534 static inline void perf_tp_register(void)
10538 static void perf_event_free_filter(struct perf_event *event)
10542 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog,
10548 void perf_event_free_bpf_prog(struct perf_event *event)
10551 #endif /* CONFIG_EVENT_TRACING */
10553 #ifdef CONFIG_HAVE_HW_BREAKPOINT
10554 void perf_bp_event(struct perf_event *bp, void *data)
10556 struct perf_sample_data sample;
10557 struct pt_regs *regs = data;
10559 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
10561 if (!bp->hw.state && !perf_exclude_event(bp, regs))
10562 perf_swevent_event(bp, 1, &sample, regs);
10567 * Allocate a new address filter
10569 static struct perf_addr_filter *
10570 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
10572 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
10573 struct perf_addr_filter *filter;
10575 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
10579 INIT_LIST_HEAD(&filter->entry);
10580 list_add_tail(&filter->entry, filters);
10585 static void free_filters_list(struct list_head *filters)
10587 struct perf_addr_filter *filter, *iter;
10589 list_for_each_entry_safe(filter, iter, filters, entry) {
10590 path_put(&filter->path);
10591 list_del(&filter->entry);
10597 * Free existing address filters and optionally install new ones
10599 static void perf_addr_filters_splice(struct perf_event *event,
10600 struct list_head *head)
10602 unsigned long flags;
10605 if (!has_addr_filter(event))
10608 /* don't bother with children, they don't have their own filters */
10612 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10614 list_splice_init(&event->addr_filters.list, &list);
10616 list_splice(head, &event->addr_filters.list);
10618 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10620 free_filters_list(&list);
10624 * Scan through mm's vmas and see if one of them matches the
10625 * @filter; if so, adjust filter's address range.
10626 * Called with mm::mmap_lock down for reading.
10628 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10629 struct mm_struct *mm,
10630 struct perf_addr_filter_range *fr)
10632 struct vm_area_struct *vma;
10633 VMA_ITERATOR(vmi, mm, 0);
10635 for_each_vma(vmi, vma) {
10639 if (perf_addr_filter_vma_adjust(filter, vma, fr))
10645 * Update event's address range filters based on the
10646 * task's existing mappings, if any.
10648 static void perf_event_addr_filters_apply(struct perf_event *event)
10650 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10651 struct task_struct *task = READ_ONCE(event->ctx->task);
10652 struct perf_addr_filter *filter;
10653 struct mm_struct *mm = NULL;
10654 unsigned int count = 0;
10655 unsigned long flags;
10658 * We may observe TASK_TOMBSTONE, which means that the event tear-down
10659 * will stop on the parent's child_mutex that our caller is also holding
10661 if (task == TASK_TOMBSTONE)
10664 if (ifh->nr_file_filters) {
10665 mm = get_task_mm(task);
10669 mmap_read_lock(mm);
10672 raw_spin_lock_irqsave(&ifh->lock, flags);
10673 list_for_each_entry(filter, &ifh->list, entry) {
10674 if (filter->path.dentry) {
10676 * Adjust base offset if the filter is associated to a
10677 * binary that needs to be mapped:
10679 event->addr_filter_ranges[count].start = 0;
10680 event->addr_filter_ranges[count].size = 0;
10682 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10684 event->addr_filter_ranges[count].start = filter->offset;
10685 event->addr_filter_ranges[count].size = filter->size;
10691 event->addr_filters_gen++;
10692 raw_spin_unlock_irqrestore(&ifh->lock, flags);
10694 if (ifh->nr_file_filters) {
10695 mmap_read_unlock(mm);
10701 perf_event_stop(event, 1);
10705 * Address range filtering: limiting the data to certain
10706 * instruction address ranges. Filters are ioctl()ed to us from
10707 * userspace as ascii strings.
10709 * Filter string format:
10711 * ACTION RANGE_SPEC
10712 * where ACTION is one of the
10713 * * "filter": limit the trace to this region
10714 * * "start": start tracing from this address
10715 * * "stop": stop tracing at this address/region;
10717 * * for kernel addresses: <start address>[/<size>]
10718 * * for object files: <start address>[/<size>]@</path/to/object/file>
10720 * if <size> is not specified or is zero, the range is treated as a single
10721 * address; not valid for ACTION=="filter".
10735 IF_STATE_ACTION = 0,
10740 static const match_table_t if_tokens = {
10741 { IF_ACT_FILTER, "filter" },
10742 { IF_ACT_START, "start" },
10743 { IF_ACT_STOP, "stop" },
10744 { IF_SRC_FILE, "%u/%u@%s" },
10745 { IF_SRC_KERNEL, "%u/%u" },
10746 { IF_SRC_FILEADDR, "%u@%s" },
10747 { IF_SRC_KERNELADDR, "%u" },
10748 { IF_ACT_NONE, NULL },
10752 * Address filter string parser
10755 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10756 struct list_head *filters)
10758 struct perf_addr_filter *filter = NULL;
10759 char *start, *orig, *filename = NULL;
10760 substring_t args[MAX_OPT_ARGS];
10761 int state = IF_STATE_ACTION, token;
10762 unsigned int kernel = 0;
10765 orig = fstr = kstrdup(fstr, GFP_KERNEL);
10769 while ((start = strsep(&fstr, " ,\n")) != NULL) {
10770 static const enum perf_addr_filter_action_t actions[] = {
10771 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10772 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10773 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10780 /* filter definition begins */
10781 if (state == IF_STATE_ACTION) {
10782 filter = perf_addr_filter_new(event, filters);
10787 token = match_token(start, if_tokens, args);
10789 case IF_ACT_FILTER:
10792 if (state != IF_STATE_ACTION)
10795 filter->action = actions[token];
10796 state = IF_STATE_SOURCE;
10799 case IF_SRC_KERNELADDR:
10800 case IF_SRC_KERNEL:
10804 case IF_SRC_FILEADDR:
10806 if (state != IF_STATE_SOURCE)
10810 ret = kstrtoul(args[0].from, 0, &filter->offset);
10814 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10816 ret = kstrtoul(args[1].from, 0, &filter->size);
10821 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10822 int fpos = token == IF_SRC_FILE ? 2 : 1;
10825 filename = match_strdup(&args[fpos]);
10832 state = IF_STATE_END;
10840 * Filter definition is fully parsed, validate and install it.
10841 * Make sure that it doesn't contradict itself or the event's
10844 if (state == IF_STATE_END) {
10848 * ACTION "filter" must have a non-zero length region
10851 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10860 * For now, we only support file-based filters
10861 * in per-task events; doing so for CPU-wide
10862 * events requires additional context switching
10863 * trickery, since same object code will be
10864 * mapped at different virtual addresses in
10865 * different processes.
10868 if (!event->ctx->task)
10871 /* look up the path and grab its inode */
10872 ret = kern_path(filename, LOOKUP_FOLLOW,
10878 if (!filter->path.dentry ||
10879 !S_ISREG(d_inode(filter->path.dentry)
10883 event->addr_filters.nr_file_filters++;
10886 /* ready to consume more filters */
10889 state = IF_STATE_ACTION;
10895 if (state != IF_STATE_ACTION)
10905 free_filters_list(filters);
10912 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10914 LIST_HEAD(filters);
10918 * Since this is called in perf_ioctl() path, we're already holding
10921 lockdep_assert_held(&event->ctx->mutex);
10923 if (WARN_ON_ONCE(event->parent))
10926 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10928 goto fail_clear_files;
10930 ret = event->pmu->addr_filters_validate(&filters);
10932 goto fail_free_filters;
10934 /* remove existing filters, if any */
10935 perf_addr_filters_splice(event, &filters);
10937 /* install new filters */
10938 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10943 free_filters_list(&filters);
10946 event->addr_filters.nr_file_filters = 0;
10951 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10956 filter_str = strndup_user(arg, PAGE_SIZE);
10957 if (IS_ERR(filter_str))
10958 return PTR_ERR(filter_str);
10960 #ifdef CONFIG_EVENT_TRACING
10961 if (perf_event_is_tracing(event)) {
10962 struct perf_event_context *ctx = event->ctx;
10965 * Beware, here be dragons!!
10967 * the tracepoint muck will deadlock against ctx->mutex, but
10968 * the tracepoint stuff does not actually need it. So
10969 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10970 * already have a reference on ctx.
10972 * This can result in event getting moved to a different ctx,
10973 * but that does not affect the tracepoint state.
10975 mutex_unlock(&ctx->mutex);
10976 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10977 mutex_lock(&ctx->mutex);
10980 if (has_addr_filter(event))
10981 ret = perf_event_set_addr_filter(event, filter_str);
10988 * hrtimer based swevent callback
10991 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10993 enum hrtimer_restart ret = HRTIMER_RESTART;
10994 struct perf_sample_data data;
10995 struct pt_regs *regs;
10996 struct perf_event *event;
10999 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
11001 if (event->state != PERF_EVENT_STATE_ACTIVE)
11002 return HRTIMER_NORESTART;
11004 event->pmu->read(event);
11006 perf_sample_data_init(&data, 0, event->hw.last_period);
11007 regs = get_irq_regs();
11009 if (regs && !perf_exclude_event(event, regs)) {
11010 if (!(event->attr.exclude_idle && is_idle_task(current)))
11011 if (__perf_event_overflow(event, 1, &data, regs))
11012 ret = HRTIMER_NORESTART;
11015 period = max_t(u64, 10000, event->hw.sample_period);
11016 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
11021 static void perf_swevent_start_hrtimer(struct perf_event *event)
11023 struct hw_perf_event *hwc = &event->hw;
11026 if (!is_sampling_event(event))
11029 period = local64_read(&hwc->period_left);
11034 local64_set(&hwc->period_left, 0);
11036 period = max_t(u64, 10000, hwc->sample_period);
11038 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
11039 HRTIMER_MODE_REL_PINNED_HARD);
11042 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
11044 struct hw_perf_event *hwc = &event->hw;
11046 if (is_sampling_event(event)) {
11047 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
11048 local64_set(&hwc->period_left, ktime_to_ns(remaining));
11050 hrtimer_cancel(&hwc->hrtimer);
11054 static void perf_swevent_init_hrtimer(struct perf_event *event)
11056 struct hw_perf_event *hwc = &event->hw;
11058 if (!is_sampling_event(event))
11061 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
11062 hwc->hrtimer.function = perf_swevent_hrtimer;
11065 * Since hrtimers have a fixed rate, we can do a static freq->period
11066 * mapping and avoid the whole period adjust feedback stuff.
11068 if (event->attr.freq) {
11069 long freq = event->attr.sample_freq;
11071 event->attr.sample_period = NSEC_PER_SEC / freq;
11072 hwc->sample_period = event->attr.sample_period;
11073 local64_set(&hwc->period_left, hwc->sample_period);
11074 hwc->last_period = hwc->sample_period;
11075 event->attr.freq = 0;
11080 * Software event: cpu wall time clock
11083 static void cpu_clock_event_update(struct perf_event *event)
11088 now = local_clock();
11089 prev = local64_xchg(&event->hw.prev_count, now);
11090 local64_add(now - prev, &event->count);
11093 static void cpu_clock_event_start(struct perf_event *event, int flags)
11095 local64_set(&event->hw.prev_count, local_clock());
11096 perf_swevent_start_hrtimer(event);
11099 static void cpu_clock_event_stop(struct perf_event *event, int flags)
11101 perf_swevent_cancel_hrtimer(event);
11102 cpu_clock_event_update(event);
11105 static int cpu_clock_event_add(struct perf_event *event, int flags)
11107 if (flags & PERF_EF_START)
11108 cpu_clock_event_start(event, flags);
11109 perf_event_update_userpage(event);
11114 static void cpu_clock_event_del(struct perf_event *event, int flags)
11116 cpu_clock_event_stop(event, flags);
11119 static void cpu_clock_event_read(struct perf_event *event)
11121 cpu_clock_event_update(event);
11124 static int cpu_clock_event_init(struct perf_event *event)
11126 if (event->attr.type != perf_cpu_clock.type)
11129 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
11133 * no branch sampling for software events
11135 if (has_branch_stack(event))
11136 return -EOPNOTSUPP;
11138 perf_swevent_init_hrtimer(event);
11143 static struct pmu perf_cpu_clock = {
11144 .task_ctx_nr = perf_sw_context,
11146 .capabilities = PERF_PMU_CAP_NO_NMI,
11147 .dev = PMU_NULL_DEV,
11149 .event_init = cpu_clock_event_init,
11150 .add = cpu_clock_event_add,
11151 .del = cpu_clock_event_del,
11152 .start = cpu_clock_event_start,
11153 .stop = cpu_clock_event_stop,
11154 .read = cpu_clock_event_read,
11158 * Software event: task time clock
11161 static void task_clock_event_update(struct perf_event *event, u64 now)
11166 prev = local64_xchg(&event->hw.prev_count, now);
11167 delta = now - prev;
11168 local64_add(delta, &event->count);
11171 static void task_clock_event_start(struct perf_event *event, int flags)
11173 local64_set(&event->hw.prev_count, event->ctx->time);
11174 perf_swevent_start_hrtimer(event);
11177 static void task_clock_event_stop(struct perf_event *event, int flags)
11179 perf_swevent_cancel_hrtimer(event);
11180 task_clock_event_update(event, event->ctx->time);
11183 static int task_clock_event_add(struct perf_event *event, int flags)
11185 if (flags & PERF_EF_START)
11186 task_clock_event_start(event, flags);
11187 perf_event_update_userpage(event);
11192 static void task_clock_event_del(struct perf_event *event, int flags)
11194 task_clock_event_stop(event, PERF_EF_UPDATE);
11197 static void task_clock_event_read(struct perf_event *event)
11199 u64 now = perf_clock();
11200 u64 delta = now - event->ctx->timestamp;
11201 u64 time = event->ctx->time + delta;
11203 task_clock_event_update(event, time);
11206 static int task_clock_event_init(struct perf_event *event)
11208 if (event->attr.type != perf_task_clock.type)
11211 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
11215 * no branch sampling for software events
11217 if (has_branch_stack(event))
11218 return -EOPNOTSUPP;
11220 perf_swevent_init_hrtimer(event);
11225 static struct pmu perf_task_clock = {
11226 .task_ctx_nr = perf_sw_context,
11228 .capabilities = PERF_PMU_CAP_NO_NMI,
11229 .dev = PMU_NULL_DEV,
11231 .event_init = task_clock_event_init,
11232 .add = task_clock_event_add,
11233 .del = task_clock_event_del,
11234 .start = task_clock_event_start,
11235 .stop = task_clock_event_stop,
11236 .read = task_clock_event_read,
11239 static void perf_pmu_nop_void(struct pmu *pmu)
11243 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
11247 static int perf_pmu_nop_int(struct pmu *pmu)
11252 static int perf_event_nop_int(struct perf_event *event, u64 value)
11257 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
11259 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
11261 __this_cpu_write(nop_txn_flags, flags);
11263 if (flags & ~PERF_PMU_TXN_ADD)
11266 perf_pmu_disable(pmu);
11269 static int perf_pmu_commit_txn(struct pmu *pmu)
11271 unsigned int flags = __this_cpu_read(nop_txn_flags);
11273 __this_cpu_write(nop_txn_flags, 0);
11275 if (flags & ~PERF_PMU_TXN_ADD)
11278 perf_pmu_enable(pmu);
11282 static void perf_pmu_cancel_txn(struct pmu *pmu)
11284 unsigned int flags = __this_cpu_read(nop_txn_flags);
11286 __this_cpu_write(nop_txn_flags, 0);
11288 if (flags & ~PERF_PMU_TXN_ADD)
11291 perf_pmu_enable(pmu);
11294 static int perf_event_idx_default(struct perf_event *event)
11299 static void free_pmu_context(struct pmu *pmu)
11301 free_percpu(pmu->cpu_pmu_context);
11305 * Let userspace know that this PMU supports address range filtering:
11307 static ssize_t nr_addr_filters_show(struct device *dev,
11308 struct device_attribute *attr,
11311 struct pmu *pmu = dev_get_drvdata(dev);
11313 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
11315 DEVICE_ATTR_RO(nr_addr_filters);
11317 static struct idr pmu_idr;
11320 type_show(struct device *dev, struct device_attribute *attr, char *page)
11322 struct pmu *pmu = dev_get_drvdata(dev);
11324 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type);
11326 static DEVICE_ATTR_RO(type);
11329 perf_event_mux_interval_ms_show(struct device *dev,
11330 struct device_attribute *attr,
11333 struct pmu *pmu = dev_get_drvdata(dev);
11335 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms);
11338 static DEFINE_MUTEX(mux_interval_mutex);
11341 perf_event_mux_interval_ms_store(struct device *dev,
11342 struct device_attribute *attr,
11343 const char *buf, size_t count)
11345 struct pmu *pmu = dev_get_drvdata(dev);
11346 int timer, cpu, ret;
11348 ret = kstrtoint(buf, 0, &timer);
11355 /* same value, noting to do */
11356 if (timer == pmu->hrtimer_interval_ms)
11359 mutex_lock(&mux_interval_mutex);
11360 pmu->hrtimer_interval_ms = timer;
11362 /* update all cpuctx for this PMU */
11364 for_each_online_cpu(cpu) {
11365 struct perf_cpu_pmu_context *cpc;
11366 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11367 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
11369 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc);
11371 cpus_read_unlock();
11372 mutex_unlock(&mux_interval_mutex);
11376 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
11378 static struct attribute *pmu_dev_attrs[] = {
11379 &dev_attr_type.attr,
11380 &dev_attr_perf_event_mux_interval_ms.attr,
11383 ATTRIBUTE_GROUPS(pmu_dev);
11385 static int pmu_bus_running;
11386 static struct bus_type pmu_bus = {
11387 .name = "event_source",
11388 .dev_groups = pmu_dev_groups,
11391 static void pmu_dev_release(struct device *dev)
11396 static int pmu_dev_alloc(struct pmu *pmu)
11400 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
11404 pmu->dev->groups = pmu->attr_groups;
11405 device_initialize(pmu->dev);
11407 dev_set_drvdata(pmu->dev, pmu);
11408 pmu->dev->bus = &pmu_bus;
11409 pmu->dev->parent = pmu->parent;
11410 pmu->dev->release = pmu_dev_release;
11412 ret = dev_set_name(pmu->dev, "%s", pmu->name);
11416 ret = device_add(pmu->dev);
11420 /* For PMUs with address filters, throw in an extra attribute: */
11421 if (pmu->nr_addr_filters)
11422 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
11427 if (pmu->attr_update)
11428 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
11437 device_del(pmu->dev);
11440 put_device(pmu->dev);
11444 static struct lock_class_key cpuctx_mutex;
11445 static struct lock_class_key cpuctx_lock;
11447 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
11449 int cpu, ret, max = PERF_TYPE_MAX;
11451 mutex_lock(&pmus_lock);
11453 pmu->pmu_disable_count = alloc_percpu(int);
11454 if (!pmu->pmu_disable_count)
11458 if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) {
11468 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
11472 WARN_ON(type >= 0 && ret != type);
11477 if (pmu_bus_running && !pmu->dev) {
11478 ret = pmu_dev_alloc(pmu);
11484 pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context);
11485 if (!pmu->cpu_pmu_context)
11488 for_each_possible_cpu(cpu) {
11489 struct perf_cpu_pmu_context *cpc;
11491 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu);
11492 __perf_init_event_pmu_context(&cpc->epc, pmu);
11493 __perf_mux_hrtimer_init(cpc, cpu);
11496 if (!pmu->start_txn) {
11497 if (pmu->pmu_enable) {
11499 * If we have pmu_enable/pmu_disable calls, install
11500 * transaction stubs that use that to try and batch
11501 * hardware accesses.
11503 pmu->start_txn = perf_pmu_start_txn;
11504 pmu->commit_txn = perf_pmu_commit_txn;
11505 pmu->cancel_txn = perf_pmu_cancel_txn;
11507 pmu->start_txn = perf_pmu_nop_txn;
11508 pmu->commit_txn = perf_pmu_nop_int;
11509 pmu->cancel_txn = perf_pmu_nop_void;
11513 if (!pmu->pmu_enable) {
11514 pmu->pmu_enable = perf_pmu_nop_void;
11515 pmu->pmu_disable = perf_pmu_nop_void;
11518 if (!pmu->check_period)
11519 pmu->check_period = perf_event_nop_int;
11521 if (!pmu->event_idx)
11522 pmu->event_idx = perf_event_idx_default;
11524 list_add_rcu(&pmu->entry, &pmus);
11525 atomic_set(&pmu->exclusive_cnt, 0);
11528 mutex_unlock(&pmus_lock);
11533 if (pmu->dev && pmu->dev != PMU_NULL_DEV) {
11534 device_del(pmu->dev);
11535 put_device(pmu->dev);
11539 idr_remove(&pmu_idr, pmu->type);
11542 free_percpu(pmu->pmu_disable_count);
11545 EXPORT_SYMBOL_GPL(perf_pmu_register);
11547 void perf_pmu_unregister(struct pmu *pmu)
11549 mutex_lock(&pmus_lock);
11550 list_del_rcu(&pmu->entry);
11553 * We dereference the pmu list under both SRCU and regular RCU, so
11554 * synchronize against both of those.
11556 synchronize_srcu(&pmus_srcu);
11559 free_percpu(pmu->pmu_disable_count);
11560 idr_remove(&pmu_idr, pmu->type);
11561 if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
11562 if (pmu->nr_addr_filters)
11563 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11564 device_del(pmu->dev);
11565 put_device(pmu->dev);
11567 free_pmu_context(pmu);
11568 mutex_unlock(&pmus_lock);
11570 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11572 static inline bool has_extended_regs(struct perf_event *event)
11574 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11575 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11578 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11580 struct perf_event_context *ctx = NULL;
11583 if (!try_module_get(pmu->module))
11587 * A number of pmu->event_init() methods iterate the sibling_list to,
11588 * for example, validate if the group fits on the PMU. Therefore,
11589 * if this is a sibling event, acquire the ctx->mutex to protect
11590 * the sibling_list.
11592 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11594 * This ctx->mutex can nest when we're called through
11595 * inheritance. See the perf_event_ctx_lock_nested() comment.
11597 ctx = perf_event_ctx_lock_nested(event->group_leader,
11598 SINGLE_DEPTH_NESTING);
11603 ret = pmu->event_init(event);
11606 perf_event_ctx_unlock(event->group_leader, ctx);
11609 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11610 has_extended_regs(event))
11613 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11614 event_has_any_exclude_flag(event))
11617 if (ret && event->destroy)
11618 event->destroy(event);
11622 module_put(pmu->module);
11627 static struct pmu *perf_init_event(struct perf_event *event)
11629 bool extended_type = false;
11630 int idx, type, ret;
11633 idx = srcu_read_lock(&pmus_srcu);
11636 * Save original type before calling pmu->event_init() since certain
11637 * pmus overwrites event->attr.type to forward event to another pmu.
11639 event->orig_type = event->attr.type;
11641 /* Try parent's PMU first: */
11642 if (event->parent && event->parent->pmu) {
11643 pmu = event->parent->pmu;
11644 ret = perf_try_init_event(pmu, event);
11650 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11651 * are often aliases for PERF_TYPE_RAW.
11653 type = event->attr.type;
11654 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) {
11655 type = event->attr.config >> PERF_PMU_TYPE_SHIFT;
11657 type = PERF_TYPE_RAW;
11659 extended_type = true;
11660 event->attr.config &= PERF_HW_EVENT_MASK;
11666 pmu = idr_find(&pmu_idr, type);
11669 if (event->attr.type != type && type != PERF_TYPE_RAW &&
11670 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE))
11673 ret = perf_try_init_event(pmu, event);
11674 if (ret == -ENOENT && event->attr.type != type && !extended_type) {
11675 type = event->attr.type;
11680 pmu = ERR_PTR(ret);
11685 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11686 ret = perf_try_init_event(pmu, event);
11690 if (ret != -ENOENT) {
11691 pmu = ERR_PTR(ret);
11696 pmu = ERR_PTR(-ENOENT);
11698 srcu_read_unlock(&pmus_srcu, idx);
11703 static void attach_sb_event(struct perf_event *event)
11705 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11707 raw_spin_lock(&pel->lock);
11708 list_add_rcu(&event->sb_list, &pel->list);
11709 raw_spin_unlock(&pel->lock);
11713 * We keep a list of all !task (and therefore per-cpu) events
11714 * that need to receive side-band records.
11716 * This avoids having to scan all the various PMU per-cpu contexts
11717 * looking for them.
11719 static void account_pmu_sb_event(struct perf_event *event)
11721 if (is_sb_event(event))
11722 attach_sb_event(event);
11725 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11726 static void account_freq_event_nohz(void)
11728 #ifdef CONFIG_NO_HZ_FULL
11729 /* Lock so we don't race with concurrent unaccount */
11730 spin_lock(&nr_freq_lock);
11731 if (atomic_inc_return(&nr_freq_events) == 1)
11732 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11733 spin_unlock(&nr_freq_lock);
11737 static void account_freq_event(void)
11739 if (tick_nohz_full_enabled())
11740 account_freq_event_nohz();
11742 atomic_inc(&nr_freq_events);
11746 static void account_event(struct perf_event *event)
11753 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11755 if (event->attr.mmap || event->attr.mmap_data)
11756 atomic_inc(&nr_mmap_events);
11757 if (event->attr.build_id)
11758 atomic_inc(&nr_build_id_events);
11759 if (event->attr.comm)
11760 atomic_inc(&nr_comm_events);
11761 if (event->attr.namespaces)
11762 atomic_inc(&nr_namespaces_events);
11763 if (event->attr.cgroup)
11764 atomic_inc(&nr_cgroup_events);
11765 if (event->attr.task)
11766 atomic_inc(&nr_task_events);
11767 if (event->attr.freq)
11768 account_freq_event();
11769 if (event->attr.context_switch) {
11770 atomic_inc(&nr_switch_events);
11773 if (has_branch_stack(event))
11775 if (is_cgroup_event(event))
11777 if (event->attr.ksymbol)
11778 atomic_inc(&nr_ksymbol_events);
11779 if (event->attr.bpf_event)
11780 atomic_inc(&nr_bpf_events);
11781 if (event->attr.text_poke)
11782 atomic_inc(&nr_text_poke_events);
11786 * We need the mutex here because static_branch_enable()
11787 * must complete *before* the perf_sched_count increment
11790 if (atomic_inc_not_zero(&perf_sched_count))
11793 mutex_lock(&perf_sched_mutex);
11794 if (!atomic_read(&perf_sched_count)) {
11795 static_branch_enable(&perf_sched_events);
11797 * Guarantee that all CPUs observe they key change and
11798 * call the perf scheduling hooks before proceeding to
11799 * install events that need them.
11804 * Now that we have waited for the sync_sched(), allow further
11805 * increments to by-pass the mutex.
11807 atomic_inc(&perf_sched_count);
11808 mutex_unlock(&perf_sched_mutex);
11812 account_pmu_sb_event(event);
11816 * Allocate and initialize an event structure
11818 static struct perf_event *
11819 perf_event_alloc(struct perf_event_attr *attr, int cpu,
11820 struct task_struct *task,
11821 struct perf_event *group_leader,
11822 struct perf_event *parent_event,
11823 perf_overflow_handler_t overflow_handler,
11824 void *context, int cgroup_fd)
11827 struct perf_event *event;
11828 struct hw_perf_event *hwc;
11829 long err = -EINVAL;
11832 if ((unsigned)cpu >= nr_cpu_ids) {
11833 if (!task || cpu != -1)
11834 return ERR_PTR(-EINVAL);
11836 if (attr->sigtrap && !task) {
11837 /* Requires a task: avoid signalling random tasks. */
11838 return ERR_PTR(-EINVAL);
11841 node = (cpu >= 0) ? cpu_to_node(cpu) : -1;
11842 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO,
11845 return ERR_PTR(-ENOMEM);
11848 * Single events are their own group leaders, with an
11849 * empty sibling list:
11852 group_leader = event;
11854 mutex_init(&event->child_mutex);
11855 INIT_LIST_HEAD(&event->child_list);
11857 INIT_LIST_HEAD(&event->event_entry);
11858 INIT_LIST_HEAD(&event->sibling_list);
11859 INIT_LIST_HEAD(&event->active_list);
11860 init_event_group(event);
11861 INIT_LIST_HEAD(&event->rb_entry);
11862 INIT_LIST_HEAD(&event->active_entry);
11863 INIT_LIST_HEAD(&event->addr_filters.list);
11864 INIT_HLIST_NODE(&event->hlist_entry);
11867 init_waitqueue_head(&event->waitq);
11868 init_irq_work(&event->pending_irq, perf_pending_irq);
11869 init_task_work(&event->pending_task, perf_pending_task);
11871 mutex_init(&event->mmap_mutex);
11872 raw_spin_lock_init(&event->addr_filters.lock);
11874 atomic_long_set(&event->refcount, 1);
11876 event->attr = *attr;
11877 event->group_leader = group_leader;
11881 event->parent = parent_event;
11883 event->ns = get_pid_ns(task_active_pid_ns(current));
11884 event->id = atomic64_inc_return(&perf_event_id);
11886 event->state = PERF_EVENT_STATE_INACTIVE;
11889 event->event_caps = parent_event->event_caps;
11892 event->attach_state = PERF_ATTACH_TASK;
11894 * XXX pmu::event_init needs to know what task to account to
11895 * and we cannot use the ctx information because we need the
11896 * pmu before we get a ctx.
11898 event->hw.target = get_task_struct(task);
11901 event->clock = &local_clock;
11903 event->clock = parent_event->clock;
11905 if (!overflow_handler && parent_event) {
11906 overflow_handler = parent_event->overflow_handler;
11907 context = parent_event->overflow_handler_context;
11908 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11909 if (overflow_handler == bpf_overflow_handler) {
11910 struct bpf_prog *prog = parent_event->prog;
11912 bpf_prog_inc(prog);
11913 event->prog = prog;
11914 event->orig_overflow_handler =
11915 parent_event->orig_overflow_handler;
11920 if (overflow_handler) {
11921 event->overflow_handler = overflow_handler;
11922 event->overflow_handler_context = context;
11923 } else if (is_write_backward(event)){
11924 event->overflow_handler = perf_event_output_backward;
11925 event->overflow_handler_context = NULL;
11927 event->overflow_handler = perf_event_output_forward;
11928 event->overflow_handler_context = NULL;
11931 perf_event__state_init(event);
11936 hwc->sample_period = attr->sample_period;
11937 if (attr->freq && attr->sample_freq)
11938 hwc->sample_period = 1;
11939 hwc->last_period = hwc->sample_period;
11941 local64_set(&hwc->period_left, hwc->sample_period);
11944 * We currently do not support PERF_SAMPLE_READ on inherited events.
11945 * See perf_output_read().
11947 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11950 if (!has_branch_stack(event))
11951 event->attr.branch_sample_type = 0;
11953 pmu = perf_init_event(event);
11955 err = PTR_ERR(pmu);
11960 * Disallow uncore-task events. Similarly, disallow uncore-cgroup
11961 * events (they don't make sense as the cgroup will be different
11962 * on other CPUs in the uncore mask).
11964 if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) {
11969 if (event->attr.aux_output &&
11970 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11975 if (cgroup_fd != -1) {
11976 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11981 err = exclusive_event_init(event);
11985 if (has_addr_filter(event)) {
11986 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11987 sizeof(struct perf_addr_filter_range),
11989 if (!event->addr_filter_ranges) {
11995 * Clone the parent's vma offsets: they are valid until exec()
11996 * even if the mm is not shared with the parent.
11998 if (event->parent) {
11999 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
12001 raw_spin_lock_irq(&ifh->lock);
12002 memcpy(event->addr_filter_ranges,
12003 event->parent->addr_filter_ranges,
12004 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
12005 raw_spin_unlock_irq(&ifh->lock);
12008 /* force hw sync on the address filters */
12009 event->addr_filters_gen = 1;
12012 if (!event->parent) {
12013 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
12014 err = get_callchain_buffers(attr->sample_max_stack);
12016 goto err_addr_filters;
12020 err = security_perf_event_alloc(event);
12022 goto err_callchain_buffer;
12024 /* symmetric to unaccount_event() in _free_event() */
12025 account_event(event);
12029 err_callchain_buffer:
12030 if (!event->parent) {
12031 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
12032 put_callchain_buffers();
12035 kfree(event->addr_filter_ranges);
12038 exclusive_event_destroy(event);
12041 if (is_cgroup_event(event))
12042 perf_detach_cgroup(event);
12043 if (event->destroy)
12044 event->destroy(event);
12045 module_put(pmu->module);
12047 if (event->hw.target)
12048 put_task_struct(event->hw.target);
12049 call_rcu(&event->rcu_head, free_event_rcu);
12051 return ERR_PTR(err);
12054 static int perf_copy_attr(struct perf_event_attr __user *uattr,
12055 struct perf_event_attr *attr)
12060 /* Zero the full structure, so that a short copy will be nice. */
12061 memset(attr, 0, sizeof(*attr));
12063 ret = get_user(size, &uattr->size);
12067 /* ABI compatibility quirk: */
12069 size = PERF_ATTR_SIZE_VER0;
12070 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
12073 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
12082 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
12085 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
12088 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
12091 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
12092 u64 mask = attr->branch_sample_type;
12094 /* only using defined bits */
12095 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
12098 /* at least one branch bit must be set */
12099 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
12102 /* propagate priv level, when not set for branch */
12103 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
12105 /* exclude_kernel checked on syscall entry */
12106 if (!attr->exclude_kernel)
12107 mask |= PERF_SAMPLE_BRANCH_KERNEL;
12109 if (!attr->exclude_user)
12110 mask |= PERF_SAMPLE_BRANCH_USER;
12112 if (!attr->exclude_hv)
12113 mask |= PERF_SAMPLE_BRANCH_HV;
12115 * adjust user setting (for HW filter setup)
12117 attr->branch_sample_type = mask;
12119 /* privileged levels capture (kernel, hv): check permissions */
12120 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
12121 ret = perf_allow_kernel(attr);
12127 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
12128 ret = perf_reg_validate(attr->sample_regs_user);
12133 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
12134 if (!arch_perf_have_user_stack_dump())
12138 * We have __u32 type for the size, but so far
12139 * we can only use __u16 as maximum due to the
12140 * __u16 sample size limit.
12142 if (attr->sample_stack_user >= USHRT_MAX)
12144 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
12148 if (!attr->sample_max_stack)
12149 attr->sample_max_stack = sysctl_perf_event_max_stack;
12151 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
12152 ret = perf_reg_validate(attr->sample_regs_intr);
12154 #ifndef CONFIG_CGROUP_PERF
12155 if (attr->sample_type & PERF_SAMPLE_CGROUP)
12158 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
12159 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
12162 if (!attr->inherit && attr->inherit_thread)
12165 if (attr->remove_on_exec && attr->enable_on_exec)
12168 if (attr->sigtrap && !attr->remove_on_exec)
12175 put_user(sizeof(*attr), &uattr->size);
12180 static void mutex_lock_double(struct mutex *a, struct mutex *b)
12186 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
12190 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
12192 struct perf_buffer *rb = NULL;
12195 if (!output_event) {
12196 mutex_lock(&event->mmap_mutex);
12200 /* don't allow circular references */
12201 if (event == output_event)
12205 * Don't allow cross-cpu buffers
12207 if (output_event->cpu != event->cpu)
12211 * If its not a per-cpu rb, it must be the same task.
12213 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
12217 * Mixing clocks in the same buffer is trouble you don't need.
12219 if (output_event->clock != event->clock)
12223 * Either writing ring buffer from beginning or from end.
12224 * Mixing is not allowed.
12226 if (is_write_backward(output_event) != is_write_backward(event))
12230 * If both events generate aux data, they must be on the same PMU
12232 if (has_aux(event) && has_aux(output_event) &&
12233 event->pmu != output_event->pmu)
12237 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
12238 * output_event is already on rb->event_list, and the list iteration
12239 * restarts after every removal, it is guaranteed this new event is
12240 * observed *OR* if output_event is already removed, it's guaranteed we
12241 * observe !rb->mmap_count.
12243 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
12245 /* Can't redirect output if we've got an active mmap() */
12246 if (atomic_read(&event->mmap_count))
12249 if (output_event) {
12250 /* get the rb we want to redirect to */
12251 rb = ring_buffer_get(output_event);
12255 /* did we race against perf_mmap_close() */
12256 if (!atomic_read(&rb->mmap_count)) {
12257 ring_buffer_put(rb);
12262 ring_buffer_attach(event, rb);
12266 mutex_unlock(&event->mmap_mutex);
12268 mutex_unlock(&output_event->mmap_mutex);
12274 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
12276 bool nmi_safe = false;
12279 case CLOCK_MONOTONIC:
12280 event->clock = &ktime_get_mono_fast_ns;
12284 case CLOCK_MONOTONIC_RAW:
12285 event->clock = &ktime_get_raw_fast_ns;
12289 case CLOCK_REALTIME:
12290 event->clock = &ktime_get_real_ns;
12293 case CLOCK_BOOTTIME:
12294 event->clock = &ktime_get_boottime_ns;
12298 event->clock = &ktime_get_clocktai_ns;
12305 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
12312 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task)
12314 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS;
12315 bool is_capable = perfmon_capable();
12317 if (attr->sigtrap) {
12319 * perf_event_attr::sigtrap sends signals to the other task.
12320 * Require the current task to also have CAP_KILL.
12323 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL);
12327 * If the required capabilities aren't available, checks for
12328 * ptrace permissions: upgrade to ATTACH, since sending signals
12329 * can effectively change the target task.
12331 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS;
12335 * Preserve ptrace permission check for backwards compatibility. The
12336 * ptrace check also includes checks that the current task and other
12337 * task have matching uids, and is therefore not done here explicitly.
12339 return is_capable || ptrace_may_access(task, ptrace_mode);
12343 * sys_perf_event_open - open a performance event, associate it to a task/cpu
12345 * @attr_uptr: event_id type attributes for monitoring/sampling
12348 * @group_fd: group leader event fd
12349 * @flags: perf event open flags
12351 SYSCALL_DEFINE5(perf_event_open,
12352 struct perf_event_attr __user *, attr_uptr,
12353 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
12355 struct perf_event *group_leader = NULL, *output_event = NULL;
12356 struct perf_event_pmu_context *pmu_ctx;
12357 struct perf_event *event, *sibling;
12358 struct perf_event_attr attr;
12359 struct perf_event_context *ctx;
12360 struct file *event_file = NULL;
12361 struct fd group = {NULL, 0};
12362 struct task_struct *task = NULL;
12365 int move_group = 0;
12367 int f_flags = O_RDWR;
12368 int cgroup_fd = -1;
12370 /* for future expandability... */
12371 if (flags & ~PERF_FLAG_ALL)
12374 err = perf_copy_attr(attr_uptr, &attr);
12378 /* Do we allow access to perf_event_open(2) ? */
12379 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
12383 if (!attr.exclude_kernel) {
12384 err = perf_allow_kernel(&attr);
12389 if (attr.namespaces) {
12390 if (!perfmon_capable())
12395 if (attr.sample_freq > sysctl_perf_event_sample_rate)
12398 if (attr.sample_period & (1ULL << 63))
12402 /* Only privileged users can get physical addresses */
12403 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
12404 err = perf_allow_kernel(&attr);
12409 /* REGS_INTR can leak data, lockdown must prevent this */
12410 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) {
12411 err = security_locked_down(LOCKDOWN_PERF);
12417 * In cgroup mode, the pid argument is used to pass the fd
12418 * opened to the cgroup directory in cgroupfs. The cpu argument
12419 * designates the cpu on which to monitor threads from that
12422 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
12425 if (flags & PERF_FLAG_FD_CLOEXEC)
12426 f_flags |= O_CLOEXEC;
12428 event_fd = get_unused_fd_flags(f_flags);
12432 if (group_fd != -1) {
12433 err = perf_fget_light(group_fd, &group);
12436 group_leader = group.file->private_data;
12437 if (flags & PERF_FLAG_FD_OUTPUT)
12438 output_event = group_leader;
12439 if (flags & PERF_FLAG_FD_NO_GROUP)
12440 group_leader = NULL;
12443 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
12444 task = find_lively_task_by_vpid(pid);
12445 if (IS_ERR(task)) {
12446 err = PTR_ERR(task);
12451 if (task && group_leader &&
12452 group_leader->attr.inherit != attr.inherit) {
12457 if (flags & PERF_FLAG_PID_CGROUP)
12460 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
12461 NULL, NULL, cgroup_fd);
12462 if (IS_ERR(event)) {
12463 err = PTR_ERR(event);
12467 if (is_sampling_event(event)) {
12468 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
12475 * Special case software events and allow them to be part of
12476 * any hardware group.
12480 if (attr.use_clockid) {
12481 err = perf_event_set_clock(event, attr.clockid);
12486 if (pmu->task_ctx_nr == perf_sw_context)
12487 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12490 err = down_read_interruptible(&task->signal->exec_update_lock);
12495 * We must hold exec_update_lock across this and any potential
12496 * perf_install_in_context() call for this new event to
12497 * serialize against exec() altering our credentials (and the
12498 * perf_event_exit_task() that could imply).
12501 if (!perf_check_permission(&attr, task))
12506 * Get the target context (task or percpu):
12508 ctx = find_get_context(task, event);
12510 err = PTR_ERR(ctx);
12514 mutex_lock(&ctx->mutex);
12516 if (ctx->task == TASK_TOMBSTONE) {
12523 * Check if the @cpu we're creating an event for is online.
12525 * We use the perf_cpu_context::ctx::mutex to serialize against
12526 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12528 struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu);
12530 if (!cpuctx->online) {
12536 if (group_leader) {
12540 * Do not allow a recursive hierarchy (this new sibling
12541 * becoming part of another group-sibling):
12543 if (group_leader->group_leader != group_leader)
12546 /* All events in a group should have the same clock */
12547 if (group_leader->clock != event->clock)
12551 * Make sure we're both events for the same CPU;
12552 * grouping events for different CPUs is broken; since
12553 * you can never concurrently schedule them anyhow.
12555 if (group_leader->cpu != event->cpu)
12559 * Make sure we're both on the same context; either task or cpu.
12561 if (group_leader->ctx != ctx)
12565 * Only a group leader can be exclusive or pinned
12567 if (attr.exclusive || attr.pinned)
12570 if (is_software_event(event) &&
12571 !in_software_context(group_leader)) {
12573 * If the event is a sw event, but the group_leader
12574 * is on hw context.
12576 * Allow the addition of software events to hw
12577 * groups, this is safe because software events
12578 * never fail to schedule.
12580 * Note the comment that goes with struct
12581 * perf_event_pmu_context.
12583 pmu = group_leader->pmu_ctx->pmu;
12584 } else if (!is_software_event(event)) {
12585 if (is_software_event(group_leader) &&
12586 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12588 * In case the group is a pure software group, and we
12589 * try to add a hardware event, move the whole group to
12590 * the hardware context.
12595 /* Don't allow group of multiple hw events from different pmus */
12596 if (!in_software_context(group_leader) &&
12597 group_leader->pmu_ctx->pmu != pmu)
12603 * Now that we're certain of the pmu; find the pmu_ctx.
12605 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12606 if (IS_ERR(pmu_ctx)) {
12607 err = PTR_ERR(pmu_ctx);
12610 event->pmu_ctx = pmu_ctx;
12612 if (output_event) {
12613 err = perf_event_set_output(event, output_event);
12618 if (!perf_event_validate_size(event)) {
12623 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12629 * Must be under the same ctx::mutex as perf_install_in_context(),
12630 * because we need to serialize with concurrent event creation.
12632 if (!exclusive_event_installable(event, ctx)) {
12637 WARN_ON_ONCE(ctx->parent_ctx);
12639 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags);
12640 if (IS_ERR(event_file)) {
12641 err = PTR_ERR(event_file);
12647 * This is the point on no return; we cannot fail hereafter. This is
12648 * where we start modifying current state.
12652 perf_remove_from_context(group_leader, 0);
12653 put_pmu_ctx(group_leader->pmu_ctx);
12655 for_each_sibling_event(sibling, group_leader) {
12656 perf_remove_from_context(sibling, 0);
12657 put_pmu_ctx(sibling->pmu_ctx);
12661 * Install the group siblings before the group leader.
12663 * Because a group leader will try and install the entire group
12664 * (through the sibling list, which is still in-tact), we can
12665 * end up with siblings installed in the wrong context.
12667 * By installing siblings first we NO-OP because they're not
12668 * reachable through the group lists.
12670 for_each_sibling_event(sibling, group_leader) {
12671 sibling->pmu_ctx = pmu_ctx;
12672 get_pmu_ctx(pmu_ctx);
12673 perf_event__state_init(sibling);
12674 perf_install_in_context(ctx, sibling, sibling->cpu);
12678 * Removing from the context ends up with disabled
12679 * event. What we want here is event in the initial
12680 * startup state, ready to be add into new context.
12682 group_leader->pmu_ctx = pmu_ctx;
12683 get_pmu_ctx(pmu_ctx);
12684 perf_event__state_init(group_leader);
12685 perf_install_in_context(ctx, group_leader, group_leader->cpu);
12689 * Precalculate sample_data sizes; do while holding ctx::mutex such
12690 * that we're serialized against further additions and before
12691 * perf_install_in_context() which is the point the event is active and
12692 * can use these values.
12694 perf_event__header_size(event);
12695 perf_event__id_header_size(event);
12697 event->owner = current;
12699 perf_install_in_context(ctx, event, event->cpu);
12700 perf_unpin_context(ctx);
12702 mutex_unlock(&ctx->mutex);
12705 up_read(&task->signal->exec_update_lock);
12706 put_task_struct(task);
12709 mutex_lock(¤t->perf_event_mutex);
12710 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12711 mutex_unlock(¤t->perf_event_mutex);
12714 * Drop the reference on the group_event after placing the
12715 * new event on the sibling_list. This ensures destruction
12716 * of the group leader will find the pointer to itself in
12717 * perf_group_detach().
12720 fd_install(event_fd, event_file);
12724 put_pmu_ctx(event->pmu_ctx);
12725 event->pmu_ctx = NULL; /* _free_event() */
12727 mutex_unlock(&ctx->mutex);
12728 perf_unpin_context(ctx);
12732 up_read(&task->signal->exec_update_lock);
12737 put_task_struct(task);
12741 put_unused_fd(event_fd);
12746 * perf_event_create_kernel_counter
12748 * @attr: attributes of the counter to create
12749 * @cpu: cpu in which the counter is bound
12750 * @task: task to profile (NULL for percpu)
12751 * @overflow_handler: callback to trigger when we hit the event
12752 * @context: context data could be used in overflow_handler callback
12754 struct perf_event *
12755 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12756 struct task_struct *task,
12757 perf_overflow_handler_t overflow_handler,
12760 struct perf_event_pmu_context *pmu_ctx;
12761 struct perf_event_context *ctx;
12762 struct perf_event *event;
12767 * Grouping is not supported for kernel events, neither is 'AUX',
12768 * make sure the caller's intentions are adjusted.
12770 if (attr->aux_output)
12771 return ERR_PTR(-EINVAL);
12773 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12774 overflow_handler, context, -1);
12775 if (IS_ERR(event)) {
12776 err = PTR_ERR(event);
12780 /* Mark owner so we could distinguish it from user events. */
12781 event->owner = TASK_TOMBSTONE;
12784 if (pmu->task_ctx_nr == perf_sw_context)
12785 event->event_caps |= PERF_EV_CAP_SOFTWARE;
12788 * Get the target context (task or percpu):
12790 ctx = find_get_context(task, event);
12792 err = PTR_ERR(ctx);
12796 WARN_ON_ONCE(ctx->parent_ctx);
12797 mutex_lock(&ctx->mutex);
12798 if (ctx->task == TASK_TOMBSTONE) {
12803 pmu_ctx = find_get_pmu_context(pmu, ctx, event);
12804 if (IS_ERR(pmu_ctx)) {
12805 err = PTR_ERR(pmu_ctx);
12808 event->pmu_ctx = pmu_ctx;
12812 * Check if the @cpu we're creating an event for is online.
12814 * We use the perf_cpu_context::ctx::mutex to serialize against
12815 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12817 struct perf_cpu_context *cpuctx =
12818 container_of(ctx, struct perf_cpu_context, ctx);
12819 if (!cpuctx->online) {
12825 if (!exclusive_event_installable(event, ctx)) {
12830 perf_install_in_context(ctx, event, event->cpu);
12831 perf_unpin_context(ctx);
12832 mutex_unlock(&ctx->mutex);
12837 put_pmu_ctx(pmu_ctx);
12838 event->pmu_ctx = NULL; /* _free_event() */
12840 mutex_unlock(&ctx->mutex);
12841 perf_unpin_context(ctx);
12846 return ERR_PTR(err);
12848 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12850 static void __perf_pmu_remove(struct perf_event_context *ctx,
12851 int cpu, struct pmu *pmu,
12852 struct perf_event_groups *groups,
12853 struct list_head *events)
12855 struct perf_event *event, *sibling;
12857 perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
12858 perf_remove_from_context(event, 0);
12859 put_pmu_ctx(event->pmu_ctx);
12860 list_add(&event->migrate_entry, events);
12862 for_each_sibling_event(sibling, event) {
12863 perf_remove_from_context(sibling, 0);
12864 put_pmu_ctx(sibling->pmu_ctx);
12865 list_add(&sibling->migrate_entry, events);
12870 static void __perf_pmu_install_event(struct pmu *pmu,
12871 struct perf_event_context *ctx,
12872 int cpu, struct perf_event *event)
12874 struct perf_event_pmu_context *epc;
12877 epc = find_get_pmu_context(pmu, ctx, event);
12878 event->pmu_ctx = epc;
12880 if (event->state >= PERF_EVENT_STATE_OFF)
12881 event->state = PERF_EVENT_STATE_INACTIVE;
12882 perf_install_in_context(ctx, event, cpu);
12885 static void __perf_pmu_install(struct perf_event_context *ctx,
12886 int cpu, struct pmu *pmu, struct list_head *events)
12888 struct perf_event *event, *tmp;
12891 * Re-instate events in 2 passes.
12893 * Skip over group leaders and only install siblings on this first
12894 * pass, siblings will not get enabled without a leader, however a
12895 * leader will enable its siblings, even if those are still on the old
12898 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12899 if (event->group_leader == event)
12902 list_del(&event->migrate_entry);
12903 __perf_pmu_install_event(pmu, ctx, cpu, event);
12907 * Once all the siblings are setup properly, install the group leaders
12910 list_for_each_entry_safe(event, tmp, events, migrate_entry) {
12911 list_del(&event->migrate_entry);
12912 __perf_pmu_install_event(pmu, ctx, cpu, event);
12916 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12918 struct perf_event_context *src_ctx, *dst_ctx;
12921 src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx;
12922 dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx;
12925 * See perf_event_ctx_lock() for comments on the details
12926 * of swizzling perf_event::ctx.
12928 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12930 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events);
12931 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events);
12933 if (!list_empty(&events)) {
12935 * Wait for the events to quiesce before re-instating them.
12939 __perf_pmu_install(dst_ctx, dst_cpu, pmu, &events);
12942 mutex_unlock(&dst_ctx->mutex);
12943 mutex_unlock(&src_ctx->mutex);
12945 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12947 static void sync_child_event(struct perf_event *child_event)
12949 struct perf_event *parent_event = child_event->parent;
12952 if (child_event->attr.inherit_stat) {
12953 struct task_struct *task = child_event->ctx->task;
12955 if (task && task != TASK_TOMBSTONE)
12956 perf_event_read_event(child_event, task);
12959 child_val = perf_event_count(child_event);
12962 * Add back the child's count to the parent's count:
12964 atomic64_add(child_val, &parent_event->child_count);
12965 atomic64_add(child_event->total_time_enabled,
12966 &parent_event->child_total_time_enabled);
12967 atomic64_add(child_event->total_time_running,
12968 &parent_event->child_total_time_running);
12972 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx)
12974 struct perf_event *parent_event = event->parent;
12975 unsigned long detach_flags = 0;
12977 if (parent_event) {
12979 * Do not destroy the 'original' grouping; because of the
12980 * context switch optimization the original events could've
12981 * ended up in a random child task.
12983 * If we were to destroy the original group, all group related
12984 * operations would cease to function properly after this
12985 * random child dies.
12987 * Do destroy all inherited groups, we don't care about those
12988 * and being thorough is better.
12990 detach_flags = DETACH_GROUP | DETACH_CHILD;
12991 mutex_lock(&parent_event->child_mutex);
12994 perf_remove_from_context(event, detach_flags);
12996 raw_spin_lock_irq(&ctx->lock);
12997 if (event->state > PERF_EVENT_STATE_EXIT)
12998 perf_event_set_state(event, PERF_EVENT_STATE_EXIT);
12999 raw_spin_unlock_irq(&ctx->lock);
13002 * Child events can be freed.
13004 if (parent_event) {
13005 mutex_unlock(&parent_event->child_mutex);
13007 * Kick perf_poll() for is_event_hup();
13009 perf_event_wakeup(parent_event);
13011 put_event(parent_event);
13016 * Parent events are governed by their filedesc, retain them.
13018 perf_event_wakeup(event);
13021 static void perf_event_exit_task_context(struct task_struct *child)
13023 struct perf_event_context *child_ctx, *clone_ctx = NULL;
13024 struct perf_event *child_event, *next;
13026 WARN_ON_ONCE(child != current);
13028 child_ctx = perf_pin_task_context(child);
13033 * In order to reduce the amount of tricky in ctx tear-down, we hold
13034 * ctx::mutex over the entire thing. This serializes against almost
13035 * everything that wants to access the ctx.
13037 * The exception is sys_perf_event_open() /
13038 * perf_event_create_kernel_count() which does find_get_context()
13039 * without ctx::mutex (it cannot because of the move_group double mutex
13040 * lock thing). See the comments in perf_install_in_context().
13042 mutex_lock(&child_ctx->mutex);
13045 * In a single ctx::lock section, de-schedule the events and detach the
13046 * context from the task such that we cannot ever get it scheduled back
13049 raw_spin_lock_irq(&child_ctx->lock);
13050 task_ctx_sched_out(child_ctx, EVENT_ALL);
13053 * Now that the context is inactive, destroy the task <-> ctx relation
13054 * and mark the context dead.
13056 RCU_INIT_POINTER(child->perf_event_ctxp, NULL);
13057 put_ctx(child_ctx); /* cannot be last */
13058 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
13059 put_task_struct(current); /* cannot be last */
13061 clone_ctx = unclone_ctx(child_ctx);
13062 raw_spin_unlock_irq(&child_ctx->lock);
13065 put_ctx(clone_ctx);
13068 * Report the task dead after unscheduling the events so that we
13069 * won't get any samples after PERF_RECORD_EXIT. We can however still
13070 * get a few PERF_RECORD_READ events.
13072 perf_event_task(child, child_ctx, 0);
13074 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
13075 perf_event_exit_event(child_event, child_ctx);
13077 mutex_unlock(&child_ctx->mutex);
13079 put_ctx(child_ctx);
13083 * When a child task exits, feed back event values to parent events.
13085 * Can be called with exec_update_lock held when called from
13086 * setup_new_exec().
13088 void perf_event_exit_task(struct task_struct *child)
13090 struct perf_event *event, *tmp;
13092 mutex_lock(&child->perf_event_mutex);
13093 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
13095 list_del_init(&event->owner_entry);
13098 * Ensure the list deletion is visible before we clear
13099 * the owner, closes a race against perf_release() where
13100 * we need to serialize on the owner->perf_event_mutex.
13102 smp_store_release(&event->owner, NULL);
13104 mutex_unlock(&child->perf_event_mutex);
13106 perf_event_exit_task_context(child);
13109 * The perf_event_exit_task_context calls perf_event_task
13110 * with child's task_ctx, which generates EXIT events for
13111 * child contexts and sets child->perf_event_ctxp[] to NULL.
13112 * At this point we need to send EXIT events to cpu contexts.
13114 perf_event_task(child, NULL, 0);
13117 static void perf_free_event(struct perf_event *event,
13118 struct perf_event_context *ctx)
13120 struct perf_event *parent = event->parent;
13122 if (WARN_ON_ONCE(!parent))
13125 mutex_lock(&parent->child_mutex);
13126 list_del_init(&event->child_list);
13127 mutex_unlock(&parent->child_mutex);
13131 raw_spin_lock_irq(&ctx->lock);
13132 perf_group_detach(event);
13133 list_del_event(event, ctx);
13134 raw_spin_unlock_irq(&ctx->lock);
13139 * Free a context as created by inheritance by perf_event_init_task() below,
13140 * used by fork() in case of fail.
13142 * Even though the task has never lived, the context and events have been
13143 * exposed through the child_list, so we must take care tearing it all down.
13145 void perf_event_free_task(struct task_struct *task)
13147 struct perf_event_context *ctx;
13148 struct perf_event *event, *tmp;
13150 ctx = rcu_access_pointer(task->perf_event_ctxp);
13154 mutex_lock(&ctx->mutex);
13155 raw_spin_lock_irq(&ctx->lock);
13157 * Destroy the task <-> ctx relation and mark the context dead.
13159 * This is important because even though the task hasn't been
13160 * exposed yet the context has been (through child_list).
13162 RCU_INIT_POINTER(task->perf_event_ctxp, NULL);
13163 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
13164 put_task_struct(task); /* cannot be last */
13165 raw_spin_unlock_irq(&ctx->lock);
13168 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
13169 perf_free_event(event, ctx);
13171 mutex_unlock(&ctx->mutex);
13174 * perf_event_release_kernel() could've stolen some of our
13175 * child events and still have them on its free_list. In that
13176 * case we must wait for these events to have been freed (in
13177 * particular all their references to this task must've been
13180 * Without this copy_process() will unconditionally free this
13181 * task (irrespective of its reference count) and
13182 * _free_event()'s put_task_struct(event->hw.target) will be a
13185 * Wait for all events to drop their context reference.
13187 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
13188 put_ctx(ctx); /* must be last */
13191 void perf_event_delayed_put(struct task_struct *task)
13193 WARN_ON_ONCE(task->perf_event_ctxp);
13196 struct file *perf_event_get(unsigned int fd)
13198 struct file *file = fget(fd);
13200 return ERR_PTR(-EBADF);
13202 if (file->f_op != &perf_fops) {
13204 return ERR_PTR(-EBADF);
13210 const struct perf_event *perf_get_event(struct file *file)
13212 if (file->f_op != &perf_fops)
13213 return ERR_PTR(-EINVAL);
13215 return file->private_data;
13218 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
13221 return ERR_PTR(-EINVAL);
13223 return &event->attr;
13227 * Inherit an event from parent task to child task.
13230 * - valid pointer on success
13231 * - NULL for orphaned events
13232 * - IS_ERR() on error
13234 static struct perf_event *
13235 inherit_event(struct perf_event *parent_event,
13236 struct task_struct *parent,
13237 struct perf_event_context *parent_ctx,
13238 struct task_struct *child,
13239 struct perf_event *group_leader,
13240 struct perf_event_context *child_ctx)
13242 enum perf_event_state parent_state = parent_event->state;
13243 struct perf_event_pmu_context *pmu_ctx;
13244 struct perf_event *child_event;
13245 unsigned long flags;
13248 * Instead of creating recursive hierarchies of events,
13249 * we link inherited events back to the original parent,
13250 * which has a filp for sure, which we use as the reference
13253 if (parent_event->parent)
13254 parent_event = parent_event->parent;
13256 child_event = perf_event_alloc(&parent_event->attr,
13259 group_leader, parent_event,
13261 if (IS_ERR(child_event))
13262 return child_event;
13264 pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
13265 if (IS_ERR(pmu_ctx)) {
13266 free_event(child_event);
13267 return ERR_CAST(pmu_ctx);
13269 child_event->pmu_ctx = pmu_ctx;
13272 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
13273 * must be under the same lock in order to serialize against
13274 * perf_event_release_kernel(), such that either we must observe
13275 * is_orphaned_event() or they will observe us on the child_list.
13277 mutex_lock(&parent_event->child_mutex);
13278 if (is_orphaned_event(parent_event) ||
13279 !atomic_long_inc_not_zero(&parent_event->refcount)) {
13280 mutex_unlock(&parent_event->child_mutex);
13281 /* task_ctx_data is freed with child_ctx */
13282 free_event(child_event);
13286 get_ctx(child_ctx);
13289 * Make the child state follow the state of the parent event,
13290 * not its attr.disabled bit. We hold the parent's mutex,
13291 * so we won't race with perf_event_{en, dis}able_family.
13293 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
13294 child_event->state = PERF_EVENT_STATE_INACTIVE;
13296 child_event->state = PERF_EVENT_STATE_OFF;
13298 if (parent_event->attr.freq) {
13299 u64 sample_period = parent_event->hw.sample_period;
13300 struct hw_perf_event *hwc = &child_event->hw;
13302 hwc->sample_period = sample_period;
13303 hwc->last_period = sample_period;
13305 local64_set(&hwc->period_left, sample_period);
13308 child_event->ctx = child_ctx;
13309 child_event->overflow_handler = parent_event->overflow_handler;
13310 child_event->overflow_handler_context
13311 = parent_event->overflow_handler_context;
13314 * Precalculate sample_data sizes
13316 perf_event__header_size(child_event);
13317 perf_event__id_header_size(child_event);
13320 * Link it up in the child's context:
13322 raw_spin_lock_irqsave(&child_ctx->lock, flags);
13323 add_event_to_ctx(child_event, child_ctx);
13324 child_event->attach_state |= PERF_ATTACH_CHILD;
13325 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
13328 * Link this into the parent event's child list
13330 list_add_tail(&child_event->child_list, &parent_event->child_list);
13331 mutex_unlock(&parent_event->child_mutex);
13333 return child_event;
13337 * Inherits an event group.
13339 * This will quietly suppress orphaned events; !inherit_event() is not an error.
13340 * This matches with perf_event_release_kernel() removing all child events.
13346 static int inherit_group(struct perf_event *parent_event,
13347 struct task_struct *parent,
13348 struct perf_event_context *parent_ctx,
13349 struct task_struct *child,
13350 struct perf_event_context *child_ctx)
13352 struct perf_event *leader;
13353 struct perf_event *sub;
13354 struct perf_event *child_ctr;
13356 leader = inherit_event(parent_event, parent, parent_ctx,
13357 child, NULL, child_ctx);
13358 if (IS_ERR(leader))
13359 return PTR_ERR(leader);
13361 * @leader can be NULL here because of is_orphaned_event(). In this
13362 * case inherit_event() will create individual events, similar to what
13363 * perf_group_detach() would do anyway.
13365 for_each_sibling_event(sub, parent_event) {
13366 child_ctr = inherit_event(sub, parent, parent_ctx,
13367 child, leader, child_ctx);
13368 if (IS_ERR(child_ctr))
13369 return PTR_ERR(child_ctr);
13371 if (sub->aux_event == parent_event && child_ctr &&
13372 !perf_get_aux_event(child_ctr, leader))
13376 leader->group_generation = parent_event->group_generation;
13381 * Creates the child task context and tries to inherit the event-group.
13383 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
13384 * inherited_all set when we 'fail' to inherit an orphaned event; this is
13385 * consistent with perf_event_release_kernel() removing all child events.
13392 inherit_task_group(struct perf_event *event, struct task_struct *parent,
13393 struct perf_event_context *parent_ctx,
13394 struct task_struct *child,
13395 u64 clone_flags, int *inherited_all)
13397 struct perf_event_context *child_ctx;
13400 if (!event->attr.inherit ||
13401 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) ||
13402 /* Do not inherit if sigtrap and signal handlers were cleared. */
13403 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) {
13404 *inherited_all = 0;
13408 child_ctx = child->perf_event_ctxp;
13411 * This is executed from the parent task context, so
13412 * inherit events that have been marked for cloning.
13413 * First allocate and initialize a context for the
13416 child_ctx = alloc_perf_context(child);
13420 child->perf_event_ctxp = child_ctx;
13423 ret = inherit_group(event, parent, parent_ctx, child, child_ctx);
13425 *inherited_all = 0;
13431 * Initialize the perf_event context in task_struct
13433 static int perf_event_init_context(struct task_struct *child, u64 clone_flags)
13435 struct perf_event_context *child_ctx, *parent_ctx;
13436 struct perf_event_context *cloned_ctx;
13437 struct perf_event *event;
13438 struct task_struct *parent = current;
13439 int inherited_all = 1;
13440 unsigned long flags;
13443 if (likely(!parent->perf_event_ctxp))
13447 * If the parent's context is a clone, pin it so it won't get
13448 * swapped under us.
13450 parent_ctx = perf_pin_task_context(parent);
13455 * No need to check if parent_ctx != NULL here; since we saw
13456 * it non-NULL earlier, the only reason for it to become NULL
13457 * is if we exit, and since we're currently in the middle of
13458 * a fork we can't be exiting at the same time.
13462 * Lock the parent list. No need to lock the child - not PID
13463 * hashed yet and not running, so nobody can access it.
13465 mutex_lock(&parent_ctx->mutex);
13468 * We dont have to disable NMIs - we are only looking at
13469 * the list, not manipulating it:
13471 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
13472 ret = inherit_task_group(event, parent, parent_ctx,
13473 child, clone_flags, &inherited_all);
13479 * We can't hold ctx->lock when iterating the ->flexible_group list due
13480 * to allocations, but we need to prevent rotation because
13481 * rotate_ctx() will change the list from interrupt context.
13483 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13484 parent_ctx->rotate_disable = 1;
13485 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13487 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
13488 ret = inherit_task_group(event, parent, parent_ctx,
13489 child, clone_flags, &inherited_all);
13494 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
13495 parent_ctx->rotate_disable = 0;
13497 child_ctx = child->perf_event_ctxp;
13499 if (child_ctx && inherited_all) {
13501 * Mark the child context as a clone of the parent
13502 * context, or of whatever the parent is a clone of.
13504 * Note that if the parent is a clone, the holding of
13505 * parent_ctx->lock avoids it from being uncloned.
13507 cloned_ctx = parent_ctx->parent_ctx;
13509 child_ctx->parent_ctx = cloned_ctx;
13510 child_ctx->parent_gen = parent_ctx->parent_gen;
13512 child_ctx->parent_ctx = parent_ctx;
13513 child_ctx->parent_gen = parent_ctx->generation;
13515 get_ctx(child_ctx->parent_ctx);
13518 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
13520 mutex_unlock(&parent_ctx->mutex);
13522 perf_unpin_context(parent_ctx);
13523 put_ctx(parent_ctx);
13529 * Initialize the perf_event context in task_struct
13531 int perf_event_init_task(struct task_struct *child, u64 clone_flags)
13535 child->perf_event_ctxp = NULL;
13536 mutex_init(&child->perf_event_mutex);
13537 INIT_LIST_HEAD(&child->perf_event_list);
13539 ret = perf_event_init_context(child, clone_flags);
13541 perf_event_free_task(child);
13548 static void __init perf_event_init_all_cpus(void)
13550 struct swevent_htable *swhash;
13551 struct perf_cpu_context *cpuctx;
13554 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
13556 for_each_possible_cpu(cpu) {
13557 swhash = &per_cpu(swevent_htable, cpu);
13558 mutex_init(&swhash->hlist_mutex);
13560 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13561 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13563 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13565 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13566 __perf_event_init_context(&cpuctx->ctx);
13567 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
13568 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
13569 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
13570 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
13571 cpuctx->heap = cpuctx->heap_default;
13575 static void perf_swevent_init_cpu(unsigned int cpu)
13577 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13579 mutex_lock(&swhash->hlist_mutex);
13580 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13581 struct swevent_hlist *hlist;
13583 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13585 rcu_assign_pointer(swhash->swevent_hlist, hlist);
13587 mutex_unlock(&swhash->hlist_mutex);
13590 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13591 static void __perf_event_exit_context(void *__info)
13593 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
13594 struct perf_event_context *ctx = __info;
13595 struct perf_event *event;
13597 raw_spin_lock(&ctx->lock);
13598 ctx_sched_out(ctx, EVENT_TIME);
13599 list_for_each_entry(event, &ctx->event_list, event_entry)
13600 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13601 raw_spin_unlock(&ctx->lock);
13604 static void perf_event_exit_cpu_context(int cpu)
13606 struct perf_cpu_context *cpuctx;
13607 struct perf_event_context *ctx;
13609 // XXX simplify cpuctx->online
13610 mutex_lock(&pmus_lock);
13611 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13612 ctx = &cpuctx->ctx;
13614 mutex_lock(&ctx->mutex);
13615 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13616 cpuctx->online = 0;
13617 mutex_unlock(&ctx->mutex);
13618 cpumask_clear_cpu(cpu, perf_online_mask);
13619 mutex_unlock(&pmus_lock);
13623 static void perf_event_exit_cpu_context(int cpu) { }
13627 int perf_event_init_cpu(unsigned int cpu)
13629 struct perf_cpu_context *cpuctx;
13630 struct perf_event_context *ctx;
13632 perf_swevent_init_cpu(cpu);
13634 mutex_lock(&pmus_lock);
13635 cpumask_set_cpu(cpu, perf_online_mask);
13636 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu);
13637 ctx = &cpuctx->ctx;
13639 mutex_lock(&ctx->mutex);
13640 cpuctx->online = 1;
13641 mutex_unlock(&ctx->mutex);
13642 mutex_unlock(&pmus_lock);
13647 int perf_event_exit_cpu(unsigned int cpu)
13649 perf_event_exit_cpu_context(cpu);
13654 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13658 for_each_online_cpu(cpu)
13659 perf_event_exit_cpu(cpu);
13665 * Run the perf reboot notifier at the very last possible moment so that
13666 * the generic watchdog code runs as long as possible.
13668 static struct notifier_block perf_reboot_notifier = {
13669 .notifier_call = perf_reboot,
13670 .priority = INT_MIN,
13673 void __init perf_event_init(void)
13677 idr_init(&pmu_idr);
13679 perf_event_init_all_cpus();
13680 init_srcu_struct(&pmus_srcu);
13681 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13682 perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1);
13683 perf_pmu_register(&perf_task_clock, "task_clock", -1);
13684 perf_tp_register();
13685 perf_event_init_cpu(smp_processor_id());
13686 register_reboot_notifier(&perf_reboot_notifier);
13688 ret = init_hw_breakpoint();
13689 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13691 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC);
13694 * Build time assertion that we keep the data_head at the intended
13695 * location. IOW, validation we got the __reserved[] size right.
13697 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13701 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13704 struct perf_pmu_events_attr *pmu_attr =
13705 container_of(attr, struct perf_pmu_events_attr, attr);
13707 if (pmu_attr->event_str)
13708 return sprintf(page, "%s\n", pmu_attr->event_str);
13712 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13714 static int __init perf_event_sysfs_init(void)
13719 mutex_lock(&pmus_lock);
13721 ret = bus_register(&pmu_bus);
13725 list_for_each_entry(pmu, &pmus, entry) {
13729 ret = pmu_dev_alloc(pmu);
13730 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13732 pmu_bus_running = 1;
13736 mutex_unlock(&pmus_lock);
13740 device_initcall(perf_event_sysfs_init);
13742 #ifdef CONFIG_CGROUP_PERF
13743 static struct cgroup_subsys_state *
13744 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13746 struct perf_cgroup *jc;
13748 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13750 return ERR_PTR(-ENOMEM);
13752 jc->info = alloc_percpu(struct perf_cgroup_info);
13755 return ERR_PTR(-ENOMEM);
13761 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13763 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13765 free_percpu(jc->info);
13769 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13771 perf_event_cgroup(css->cgroup);
13775 static int __perf_cgroup_move(void *info)
13777 struct task_struct *task = info;
13780 perf_cgroup_switch(task);
13786 static void perf_cgroup_attach(struct cgroup_taskset *tset)
13788 struct task_struct *task;
13789 struct cgroup_subsys_state *css;
13791 cgroup_taskset_for_each(task, css, tset)
13792 task_function_call(task, __perf_cgroup_move, task);
13795 struct cgroup_subsys perf_event_cgrp_subsys = {
13796 .css_alloc = perf_cgroup_css_alloc,
13797 .css_free = perf_cgroup_css_free,
13798 .css_online = perf_cgroup_css_online,
13799 .attach = perf_cgroup_attach,
13801 * Implicitly enable on dfl hierarchy so that perf events can
13802 * always be filtered by cgroup2 path as long as perf_event
13803 * controller is not mounted on a legacy hierarchy.
13805 .implicit_on_dfl = true,
13808 #endif /* CONFIG_CGROUP_PERF */
13810 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);