2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.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>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly. This will
98 * retry due to any failures in smp_call_function_single(), such as if the
99 * task_cpu() goes offline concurrently.
101 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function,
130 * cpu_function_call - call a function on the cpu
131 * @func: the function to be called
132 * @info: the function call argument
134 * Calls the function @func on the remote cpu.
136 * returns: @func return value or -ENXIO when the cpu is offline
138 static int cpu_function_call(int cpu, remote_function_f func, void *info)
140 struct remote_function_call data = {
144 .ret = -ENXIO, /* No such CPU */
147 smp_call_function_single(cpu, remote_function, &data, 1);
152 static inline struct perf_cpu_context *
153 __get_cpu_context(struct perf_event_context *ctx)
155 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
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;
182 * On task ctx scheduling...
184 * When !ctx->nr_events a task context will not be scheduled. This means
185 * we can disable the scheduler hooks (for performance) without leaving
186 * pending task ctx state.
188 * This however results in two special cases:
190 * - removing the last event from a task ctx; this is relatively straight
191 * forward and is done in __perf_remove_from_context.
193 * - adding the first event to a task ctx; this is tricky because we cannot
194 * rely on ctx->is_active and therefore cannot use event_function_call().
195 * See perf_install_in_context().
197 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
200 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
201 struct perf_event_context *, void *);
203 struct event_function_struct {
204 struct perf_event *event;
209 static int event_function(void *info)
211 struct event_function_struct *efs = info;
212 struct perf_event *event = efs->event;
213 struct perf_event_context *ctx = event->ctx;
214 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
215 struct perf_event_context *task_ctx = cpuctx->task_ctx;
218 WARN_ON_ONCE(!irqs_disabled());
220 perf_ctx_lock(cpuctx, task_ctx);
222 * Since we do the IPI call without holding ctx->lock things can have
223 * changed, double check we hit the task we set out to hit.
226 if (ctx->task != current) {
232 * We only use event_function_call() on established contexts,
233 * and event_function() is only ever called when active (or
234 * rather, we'll have bailed in task_function_call() or the
235 * above ctx->task != current test), therefore we must have
236 * ctx->is_active here.
238 WARN_ON_ONCE(!ctx->is_active);
240 * And since we have ctx->is_active, cpuctx->task_ctx must
243 WARN_ON_ONCE(task_ctx != ctx);
245 WARN_ON_ONCE(&cpuctx->ctx != ctx);
248 efs->func(event, cpuctx, ctx, efs->data);
250 perf_ctx_unlock(cpuctx, task_ctx);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
279 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task == TASK_TOMBSTONE) {
293 raw_spin_unlock_irq(&ctx->lock);
296 if (ctx->is_active) {
297 raw_spin_unlock_irq(&ctx->lock);
300 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
305 * Similar to event_function_call() + event_function(), but hard assumes IRQs
306 * are already disabled and we're on the right CPU.
308 static void event_function_local(struct perf_event *event, event_f func, void *data)
310 struct perf_event_context *ctx = event->ctx;
311 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
312 struct task_struct *task = READ_ONCE(ctx->task);
313 struct perf_event_context *task_ctx = NULL;
315 WARN_ON_ONCE(!irqs_disabled());
318 if (task == TASK_TOMBSTONE)
324 perf_ctx_lock(cpuctx, task_ctx);
327 if (task == TASK_TOMBSTONE)
332 * We must be either inactive or active and the right task,
333 * otherwise we're screwed, since we cannot IPI to somewhere
336 if (ctx->is_active) {
337 if (WARN_ON_ONCE(task != current))
340 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
344 WARN_ON_ONCE(&cpuctx->ctx != ctx);
347 func(event, cpuctx, ctx, data);
349 perf_ctx_unlock(cpuctx, task_ctx);
352 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
353 PERF_FLAG_FD_OUTPUT |\
354 PERF_FLAG_PID_CGROUP |\
355 PERF_FLAG_FD_CLOEXEC)
358 * branch priv levels that need permission checks
360 #define PERF_SAMPLE_BRANCH_PERM_PLM \
361 (PERF_SAMPLE_BRANCH_KERNEL |\
362 PERF_SAMPLE_BRANCH_HV)
365 EVENT_FLEXIBLE = 0x1,
368 /* see ctx_resched() for details */
370 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
374 * perf_sched_events : >0 events exist
375 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
378 static void perf_sched_delayed(struct work_struct *work);
379 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
380 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
381 static DEFINE_MUTEX(perf_sched_mutex);
382 static atomic_t perf_sched_count;
384 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
385 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
386 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
388 static atomic_t nr_mmap_events __read_mostly;
389 static atomic_t nr_comm_events __read_mostly;
390 static atomic_t nr_namespaces_events __read_mostly;
391 static atomic_t nr_task_events __read_mostly;
392 static atomic_t nr_freq_events __read_mostly;
393 static atomic_t nr_switch_events __read_mostly;
395 static LIST_HEAD(pmus);
396 static DEFINE_MUTEX(pmus_lock);
397 static struct srcu_struct pmus_srcu;
398 static cpumask_var_t perf_online_mask;
401 * perf event paranoia level:
402 * -1 - not paranoid at all
403 * 0 - disallow raw tracepoint access for unpriv
404 * 1 - disallow cpu events for unpriv
405 * 2 - disallow kernel profiling for unpriv
407 int sysctl_perf_event_paranoid __read_mostly = 2;
409 /* Minimum for 512 kiB + 1 user control page */
410 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
413 * max perf event sample rate
415 #define DEFAULT_MAX_SAMPLE_RATE 100000
416 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
417 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
419 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
421 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
422 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
424 static int perf_sample_allowed_ns __read_mostly =
425 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
427 static void update_perf_cpu_limits(void)
429 u64 tmp = perf_sample_period_ns;
431 tmp *= sysctl_perf_cpu_time_max_percent;
432 tmp = div_u64(tmp, 100);
436 WRITE_ONCE(perf_sample_allowed_ns, tmp);
439 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
441 int perf_proc_update_handler(struct ctl_table *table, int write,
442 void __user *buffer, size_t *lenp,
446 int perf_cpu = sysctl_perf_cpu_time_max_percent;
448 * If throttling is disabled don't allow the write:
450 if (write && (perf_cpu == 100 || perf_cpu == 0))
453 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
457 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
458 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
459 update_perf_cpu_limits();
464 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
466 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
467 void __user *buffer, size_t *lenp,
470 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
475 if (sysctl_perf_cpu_time_max_percent == 100 ||
476 sysctl_perf_cpu_time_max_percent == 0) {
478 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
479 WRITE_ONCE(perf_sample_allowed_ns, 0);
481 update_perf_cpu_limits();
488 * perf samples are done in some very critical code paths (NMIs).
489 * If they take too much CPU time, the system can lock up and not
490 * get any real work done. This will drop the sample rate when
491 * we detect that events are taking too long.
493 #define NR_ACCUMULATED_SAMPLES 128
494 static DEFINE_PER_CPU(u64, running_sample_length);
496 static u64 __report_avg;
497 static u64 __report_allowed;
499 static void perf_duration_warn(struct irq_work *w)
501 printk_ratelimited(KERN_INFO
502 "perf: interrupt took too long (%lld > %lld), lowering "
503 "kernel.perf_event_max_sample_rate to %d\n",
504 __report_avg, __report_allowed,
505 sysctl_perf_event_sample_rate);
508 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
510 void perf_sample_event_took(u64 sample_len_ns)
512 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
520 /* Decay the counter by 1 average sample. */
521 running_len = __this_cpu_read(running_sample_length);
522 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
523 running_len += sample_len_ns;
524 __this_cpu_write(running_sample_length, running_len);
527 * Note: this will be biased artifically low until we have
528 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
529 * from having to maintain a count.
531 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
532 if (avg_len <= max_len)
535 __report_avg = avg_len;
536 __report_allowed = max_len;
539 * Compute a throttle threshold 25% below the current duration.
541 avg_len += avg_len / 4;
542 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
548 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
549 WRITE_ONCE(max_samples_per_tick, max);
551 sysctl_perf_event_sample_rate = max * HZ;
552 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
554 if (!irq_work_queue(&perf_duration_work)) {
555 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
556 "kernel.perf_event_max_sample_rate to %d\n",
557 __report_avg, __report_allowed,
558 sysctl_perf_event_sample_rate);
562 static atomic64_t perf_event_id;
564 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
565 enum event_type_t event_type);
567 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
568 enum event_type_t event_type,
569 struct task_struct *task);
571 static void update_context_time(struct perf_event_context *ctx);
572 static u64 perf_event_time(struct perf_event *event);
574 void __weak perf_event_print_debug(void) { }
576 extern __weak const char *perf_pmu_name(void)
581 static inline u64 perf_clock(void)
583 return local_clock();
586 static inline u64 perf_event_clock(struct perf_event *event)
588 return event->clock();
591 #ifdef CONFIG_CGROUP_PERF
594 perf_cgroup_match(struct perf_event *event)
596 struct perf_event_context *ctx = event->ctx;
597 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
599 /* @event doesn't care about cgroup */
603 /* wants specific cgroup scope but @cpuctx isn't associated with any */
608 * Cgroup scoping is recursive. An event enabled for a cgroup is
609 * also enabled for all its descendant cgroups. If @cpuctx's
610 * cgroup is a descendant of @event's (the test covers identity
611 * case), it's a match.
613 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
614 event->cgrp->css.cgroup);
617 static inline void perf_detach_cgroup(struct perf_event *event)
619 css_put(&event->cgrp->css);
623 static inline int is_cgroup_event(struct perf_event *event)
625 return event->cgrp != NULL;
628 static inline u64 perf_cgroup_event_time(struct perf_event *event)
630 struct perf_cgroup_info *t;
632 t = per_cpu_ptr(event->cgrp->info, event->cpu);
636 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
638 struct perf_cgroup_info *info;
643 info = this_cpu_ptr(cgrp->info);
645 info->time += now - info->timestamp;
646 info->timestamp = now;
649 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
651 struct perf_cgroup *cgrp = cpuctx->cgrp;
652 struct cgroup_subsys_state *css;
655 for (css = &cgrp->css; css; css = css->parent) {
656 cgrp = container_of(css, struct perf_cgroup, css);
657 __update_cgrp_time(cgrp);
662 static inline void update_cgrp_time_from_event(struct perf_event *event)
664 struct perf_cgroup *cgrp;
667 * ensure we access cgroup data only when needed and
668 * when we know the cgroup is pinned (css_get)
670 if (!is_cgroup_event(event))
673 cgrp = perf_cgroup_from_task(current, event->ctx);
675 * Do not update time when cgroup is not active
677 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
678 __update_cgrp_time(event->cgrp);
682 perf_cgroup_set_timestamp(struct task_struct *task,
683 struct perf_event_context *ctx)
685 struct perf_cgroup *cgrp;
686 struct perf_cgroup_info *info;
687 struct cgroup_subsys_state *css;
690 * ctx->lock held by caller
691 * ensure we do not access cgroup data
692 * unless we have the cgroup pinned (css_get)
694 if (!task || !ctx->nr_cgroups)
697 cgrp = perf_cgroup_from_task(task, ctx);
699 for (css = &cgrp->css; css; css = css->parent) {
700 cgrp = container_of(css, struct perf_cgroup, css);
701 info = this_cpu_ptr(cgrp->info);
702 info->timestamp = ctx->timestamp;
706 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
708 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
709 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
712 * reschedule events based on the cgroup constraint of task.
714 * mode SWOUT : schedule out everything
715 * mode SWIN : schedule in based on cgroup for next
717 static void perf_cgroup_switch(struct task_struct *task, int mode)
719 struct perf_cpu_context *cpuctx, *tmp;
720 struct list_head *list;
724 * Disable interrupts and preemption to avoid this CPU's
725 * cgrp_cpuctx_entry to change under us.
727 local_irq_save(flags);
729 list = this_cpu_ptr(&cgrp_cpuctx_list);
730 list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
731 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
733 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
734 perf_pmu_disable(cpuctx->ctx.pmu);
736 if (mode & PERF_CGROUP_SWOUT) {
737 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
739 * must not be done before ctxswout due
740 * to event_filter_match() in event_sched_out()
745 if (mode & PERF_CGROUP_SWIN) {
746 WARN_ON_ONCE(cpuctx->cgrp);
748 * set cgrp before ctxsw in to allow
749 * event_filter_match() to not have to pass
751 * we pass the cpuctx->ctx to perf_cgroup_from_task()
752 * because cgorup events are only per-cpu
754 cpuctx->cgrp = perf_cgroup_from_task(task,
756 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
758 perf_pmu_enable(cpuctx->ctx.pmu);
759 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
762 local_irq_restore(flags);
765 static inline void perf_cgroup_sched_out(struct task_struct *task,
766 struct task_struct *next)
768 struct perf_cgroup *cgrp1;
769 struct perf_cgroup *cgrp2 = NULL;
773 * we come here when we know perf_cgroup_events > 0
774 * we do not need to pass the ctx here because we know
775 * we are holding the rcu lock
777 cgrp1 = perf_cgroup_from_task(task, NULL);
778 cgrp2 = perf_cgroup_from_task(next, NULL);
781 * only schedule out current cgroup events if we know
782 * that we are switching to a different cgroup. Otherwise,
783 * do no touch the cgroup events.
786 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
791 static inline void perf_cgroup_sched_in(struct task_struct *prev,
792 struct task_struct *task)
794 struct perf_cgroup *cgrp1;
795 struct perf_cgroup *cgrp2 = NULL;
799 * we come here when we know perf_cgroup_events > 0
800 * we do not need to pass the ctx here because we know
801 * we are holding the rcu lock
803 cgrp1 = perf_cgroup_from_task(task, NULL);
804 cgrp2 = perf_cgroup_from_task(prev, NULL);
807 * only need to schedule in cgroup events if we are changing
808 * cgroup during ctxsw. Cgroup events were not scheduled
809 * out of ctxsw out if that was not the case.
812 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
817 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
818 struct perf_event_attr *attr,
819 struct perf_event *group_leader)
821 struct perf_cgroup *cgrp;
822 struct cgroup_subsys_state *css;
823 struct fd f = fdget(fd);
829 css = css_tryget_online_from_dir(f.file->f_path.dentry,
830 &perf_event_cgrp_subsys);
836 cgrp = container_of(css, struct perf_cgroup, css);
840 * all events in a group must monitor
841 * the same cgroup because a task belongs
842 * to only one perf cgroup at a time
844 if (group_leader && group_leader->cgrp != cgrp) {
845 perf_detach_cgroup(event);
854 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
856 struct perf_cgroup_info *t;
857 t = per_cpu_ptr(event->cgrp->info, event->cpu);
858 event->shadow_ctx_time = now - t->timestamp;
862 perf_cgroup_defer_enabled(struct perf_event *event)
865 * when the current task's perf cgroup does not match
866 * the event's, we need to remember to call the
867 * perf_mark_enable() function the first time a task with
868 * a matching perf cgroup is scheduled in.
870 if (is_cgroup_event(event) && !perf_cgroup_match(event))
871 event->cgrp_defer_enabled = 1;
875 perf_cgroup_mark_enabled(struct perf_event *event,
876 struct perf_event_context *ctx)
878 struct perf_event *sub;
879 u64 tstamp = perf_event_time(event);
881 if (!event->cgrp_defer_enabled)
884 event->cgrp_defer_enabled = 0;
886 event->tstamp_enabled = tstamp - event->total_time_enabled;
887 list_for_each_entry(sub, &event->sibling_list, group_entry) {
888 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
889 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
890 sub->cgrp_defer_enabled = 0;
896 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
897 * cleared when last cgroup event is removed.
900 list_update_cgroup_event(struct perf_event *event,
901 struct perf_event_context *ctx, bool add)
903 struct perf_cpu_context *cpuctx;
904 struct list_head *cpuctx_entry;
906 if (!is_cgroup_event(event))
910 * Because cgroup events are always per-cpu events,
911 * this will always be called from the right CPU.
913 cpuctx = __get_cpu_context(ctx);
916 * Since setting cpuctx->cgrp is conditional on the current @cgrp
917 * matching the event's cgroup, we must do this for every new event,
918 * because if the first would mismatch, the second would not try again
919 * and we would leave cpuctx->cgrp unset.
921 if (add && !cpuctx->cgrp) {
922 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
924 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
928 if (add && ctx->nr_cgroups++)
930 else if (!add && --ctx->nr_cgroups)
933 /* no cgroup running */
937 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
939 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
941 list_del(cpuctx_entry);
944 #else /* !CONFIG_CGROUP_PERF */
947 perf_cgroup_match(struct perf_event *event)
952 static inline void perf_detach_cgroup(struct perf_event *event)
955 static inline int is_cgroup_event(struct perf_event *event)
960 static inline void update_cgrp_time_from_event(struct perf_event *event)
964 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
968 static inline void perf_cgroup_sched_out(struct task_struct *task,
969 struct task_struct *next)
973 static inline void perf_cgroup_sched_in(struct task_struct *prev,
974 struct task_struct *task)
978 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
979 struct perf_event_attr *attr,
980 struct perf_event *group_leader)
986 perf_cgroup_set_timestamp(struct task_struct *task,
987 struct perf_event_context *ctx)
992 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
997 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1001 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1007 perf_cgroup_defer_enabled(struct perf_event *event)
1012 perf_cgroup_mark_enabled(struct perf_event *event,
1013 struct perf_event_context *ctx)
1018 list_update_cgroup_event(struct perf_event *event,
1019 struct perf_event_context *ctx, bool add)
1026 * set default to be dependent on timer tick just
1027 * like original code
1029 #define PERF_CPU_HRTIMER (1000 / HZ)
1031 * function must be called with interrupts disabled
1033 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1035 struct perf_cpu_context *cpuctx;
1038 WARN_ON(!irqs_disabled());
1040 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1041 rotations = perf_rotate_context(cpuctx);
1043 raw_spin_lock(&cpuctx->hrtimer_lock);
1045 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1047 cpuctx->hrtimer_active = 0;
1048 raw_spin_unlock(&cpuctx->hrtimer_lock);
1050 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1053 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1055 struct hrtimer *timer = &cpuctx->hrtimer;
1056 struct pmu *pmu = cpuctx->ctx.pmu;
1059 /* no multiplexing needed for SW PMU */
1060 if (pmu->task_ctx_nr == perf_sw_context)
1064 * check default is sane, if not set then force to
1065 * default interval (1/tick)
1067 interval = pmu->hrtimer_interval_ms;
1069 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1071 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1073 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1074 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1075 timer->function = perf_mux_hrtimer_handler;
1078 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1080 struct hrtimer *timer = &cpuctx->hrtimer;
1081 struct pmu *pmu = cpuctx->ctx.pmu;
1082 unsigned long flags;
1084 /* not for SW PMU */
1085 if (pmu->task_ctx_nr == perf_sw_context)
1088 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1089 if (!cpuctx->hrtimer_active) {
1090 cpuctx->hrtimer_active = 1;
1091 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1092 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1094 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1099 static int perf_mux_hrtimer_restart_ipi(void *arg)
1101 return perf_mux_hrtimer_restart(arg);
1104 void perf_pmu_disable(struct pmu *pmu)
1106 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1108 pmu->pmu_disable(pmu);
1111 void perf_pmu_enable(struct pmu *pmu)
1113 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1115 pmu->pmu_enable(pmu);
1118 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1121 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1122 * perf_event_task_tick() are fully serialized because they're strictly cpu
1123 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1124 * disabled, while perf_event_task_tick is called from IRQ context.
1126 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1128 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1130 WARN_ON(!irqs_disabled());
1132 WARN_ON(!list_empty(&ctx->active_ctx_list));
1134 list_add(&ctx->active_ctx_list, head);
1137 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1139 WARN_ON(!irqs_disabled());
1141 WARN_ON(list_empty(&ctx->active_ctx_list));
1143 list_del_init(&ctx->active_ctx_list);
1146 static void get_ctx(struct perf_event_context *ctx)
1148 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1151 static void free_ctx(struct rcu_head *head)
1153 struct perf_event_context *ctx;
1155 ctx = container_of(head, struct perf_event_context, rcu_head);
1156 kfree(ctx->task_ctx_data);
1160 static void put_ctx(struct perf_event_context *ctx)
1162 if (atomic_dec_and_test(&ctx->refcount)) {
1163 if (ctx->parent_ctx)
1164 put_ctx(ctx->parent_ctx);
1165 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1166 put_task_struct(ctx->task);
1167 call_rcu(&ctx->rcu_head, free_ctx);
1172 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1173 * perf_pmu_migrate_context() we need some magic.
1175 * Those places that change perf_event::ctx will hold both
1176 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1178 * Lock ordering is by mutex address. There are two other sites where
1179 * perf_event_context::mutex nests and those are:
1181 * - perf_event_exit_task_context() [ child , 0 ]
1182 * perf_event_exit_event()
1183 * put_event() [ parent, 1 ]
1185 * - perf_event_init_context() [ parent, 0 ]
1186 * inherit_task_group()
1189 * perf_event_alloc()
1191 * perf_try_init_event() [ child , 1 ]
1193 * While it appears there is an obvious deadlock here -- the parent and child
1194 * nesting levels are inverted between the two. This is in fact safe because
1195 * life-time rules separate them. That is an exiting task cannot fork, and a
1196 * spawning task cannot (yet) exit.
1198 * But remember that that these are parent<->child context relations, and
1199 * migration does not affect children, therefore these two orderings should not
1202 * The change in perf_event::ctx does not affect children (as claimed above)
1203 * because the sys_perf_event_open() case will install a new event and break
1204 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1205 * concerned with cpuctx and that doesn't have children.
1207 * The places that change perf_event::ctx will issue:
1209 * perf_remove_from_context();
1210 * synchronize_rcu();
1211 * perf_install_in_context();
1213 * to affect the change. The remove_from_context() + synchronize_rcu() should
1214 * quiesce the event, after which we can install it in the new location. This
1215 * means that only external vectors (perf_fops, prctl) can perturb the event
1216 * while in transit. Therefore all such accessors should also acquire
1217 * perf_event_context::mutex to serialize against this.
1219 * However; because event->ctx can change while we're waiting to acquire
1220 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1225 * task_struct::perf_event_mutex
1226 * perf_event_context::mutex
1227 * perf_event::child_mutex;
1228 * perf_event_context::lock
1229 * perf_event::mmap_mutex
1232 static struct perf_event_context *
1233 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1235 struct perf_event_context *ctx;
1239 ctx = ACCESS_ONCE(event->ctx);
1240 if (!atomic_inc_not_zero(&ctx->refcount)) {
1246 mutex_lock_nested(&ctx->mutex, nesting);
1247 if (event->ctx != ctx) {
1248 mutex_unlock(&ctx->mutex);
1256 static inline struct perf_event_context *
1257 perf_event_ctx_lock(struct perf_event *event)
1259 return perf_event_ctx_lock_nested(event, 0);
1262 static void perf_event_ctx_unlock(struct perf_event *event,
1263 struct perf_event_context *ctx)
1265 mutex_unlock(&ctx->mutex);
1270 * This must be done under the ctx->lock, such as to serialize against
1271 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1272 * calling scheduler related locks and ctx->lock nests inside those.
1274 static __must_check struct perf_event_context *
1275 unclone_ctx(struct perf_event_context *ctx)
1277 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1279 lockdep_assert_held(&ctx->lock);
1282 ctx->parent_ctx = NULL;
1288 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1293 * only top level events have the pid namespace they were created in
1296 event = event->parent;
1298 nr = __task_pid_nr_ns(p, type, event->ns);
1299 /* avoid -1 if it is idle thread or runs in another ns */
1300 if (!nr && !pid_alive(p))
1305 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1307 return perf_event_pid_type(event, p, __PIDTYPE_TGID);
1310 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1312 return perf_event_pid_type(event, p, PIDTYPE_PID);
1316 * If we inherit events we want to return the parent event id
1319 static u64 primary_event_id(struct perf_event *event)
1324 id = event->parent->id;
1330 * Get the perf_event_context for a task and lock it.
1332 * This has to cope with with the fact that until it is locked,
1333 * the context could get moved to another task.
1335 static struct perf_event_context *
1336 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1338 struct perf_event_context *ctx;
1342 * One of the few rules of preemptible RCU is that one cannot do
1343 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1344 * part of the read side critical section was irqs-enabled -- see
1345 * rcu_read_unlock_special().
1347 * Since ctx->lock nests under rq->lock we must ensure the entire read
1348 * side critical section has interrupts disabled.
1350 local_irq_save(*flags);
1352 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1355 * If this context is a clone of another, it might
1356 * get swapped for another underneath us by
1357 * perf_event_task_sched_out, though the
1358 * rcu_read_lock() protects us from any context
1359 * getting freed. Lock the context and check if it
1360 * got swapped before we could get the lock, and retry
1361 * if so. If we locked the right context, then it
1362 * can't get swapped on us any more.
1364 raw_spin_lock(&ctx->lock);
1365 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1366 raw_spin_unlock(&ctx->lock);
1368 local_irq_restore(*flags);
1372 if (ctx->task == TASK_TOMBSTONE ||
1373 !atomic_inc_not_zero(&ctx->refcount)) {
1374 raw_spin_unlock(&ctx->lock);
1377 WARN_ON_ONCE(ctx->task != task);
1382 local_irq_restore(*flags);
1387 * Get the context for a task and increment its pin_count so it
1388 * can't get swapped to another task. This also increments its
1389 * reference count so that the context can't get freed.
1391 static struct perf_event_context *
1392 perf_pin_task_context(struct task_struct *task, int ctxn)
1394 struct perf_event_context *ctx;
1395 unsigned long flags;
1397 ctx = perf_lock_task_context(task, ctxn, &flags);
1400 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1405 static void perf_unpin_context(struct perf_event_context *ctx)
1407 unsigned long flags;
1409 raw_spin_lock_irqsave(&ctx->lock, flags);
1411 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1415 * Update the record of the current time in a context.
1417 static void update_context_time(struct perf_event_context *ctx)
1419 u64 now = perf_clock();
1421 ctx->time += now - ctx->timestamp;
1422 ctx->timestamp = now;
1425 static u64 perf_event_time(struct perf_event *event)
1427 struct perf_event_context *ctx = event->ctx;
1429 if (is_cgroup_event(event))
1430 return perf_cgroup_event_time(event);
1432 return ctx ? ctx->time : 0;
1436 * Update the total_time_enabled and total_time_running fields for a event.
1438 static void update_event_times(struct perf_event *event)
1440 struct perf_event_context *ctx = event->ctx;
1443 lockdep_assert_held(&ctx->lock);
1445 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1446 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1450 * in cgroup mode, time_enabled represents
1451 * the time the event was enabled AND active
1452 * tasks were in the monitored cgroup. This is
1453 * independent of the activity of the context as
1454 * there may be a mix of cgroup and non-cgroup events.
1456 * That is why we treat cgroup events differently
1459 if (is_cgroup_event(event))
1460 run_end = perf_cgroup_event_time(event);
1461 else if (ctx->is_active)
1462 run_end = ctx->time;
1464 run_end = event->tstamp_stopped;
1466 event->total_time_enabled = run_end - event->tstamp_enabled;
1468 if (event->state == PERF_EVENT_STATE_INACTIVE)
1469 run_end = event->tstamp_stopped;
1471 run_end = perf_event_time(event);
1473 event->total_time_running = run_end - event->tstamp_running;
1478 * Update total_time_enabled and total_time_running for all events in a group.
1480 static void update_group_times(struct perf_event *leader)
1482 struct perf_event *event;
1484 update_event_times(leader);
1485 list_for_each_entry(event, &leader->sibling_list, group_entry)
1486 update_event_times(event);
1489 static enum event_type_t get_event_type(struct perf_event *event)
1491 struct perf_event_context *ctx = event->ctx;
1492 enum event_type_t event_type;
1494 lockdep_assert_held(&ctx->lock);
1497 * It's 'group type', really, because if our group leader is
1498 * pinned, so are we.
1500 if (event->group_leader != event)
1501 event = event->group_leader;
1503 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1505 event_type |= EVENT_CPU;
1510 static struct list_head *
1511 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1513 if (event->attr.pinned)
1514 return &ctx->pinned_groups;
1516 return &ctx->flexible_groups;
1520 * Add a event from the lists for its context.
1521 * Must be called with ctx->mutex and ctx->lock held.
1524 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1526 lockdep_assert_held(&ctx->lock);
1528 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1529 event->attach_state |= PERF_ATTACH_CONTEXT;
1532 * If we're a stand alone event or group leader, we go to the context
1533 * list, group events are kept attached to the group so that
1534 * perf_group_detach can, at all times, locate all siblings.
1536 if (event->group_leader == event) {
1537 struct list_head *list;
1539 event->group_caps = event->event_caps;
1541 list = ctx_group_list(event, ctx);
1542 list_add_tail(&event->group_entry, list);
1545 list_update_cgroup_event(event, ctx, true);
1547 list_add_rcu(&event->event_entry, &ctx->event_list);
1549 if (event->attr.inherit_stat)
1556 * Initialize event state based on the perf_event_attr::disabled.
1558 static inline void perf_event__state_init(struct perf_event *event)
1560 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1561 PERF_EVENT_STATE_INACTIVE;
1564 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1566 int entry = sizeof(u64); /* value */
1570 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1571 size += sizeof(u64);
1573 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1574 size += sizeof(u64);
1576 if (event->attr.read_format & PERF_FORMAT_ID)
1577 entry += sizeof(u64);
1579 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1581 size += sizeof(u64);
1585 event->read_size = size;
1588 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1590 struct perf_sample_data *data;
1593 if (sample_type & PERF_SAMPLE_IP)
1594 size += sizeof(data->ip);
1596 if (sample_type & PERF_SAMPLE_ADDR)
1597 size += sizeof(data->addr);
1599 if (sample_type & PERF_SAMPLE_PERIOD)
1600 size += sizeof(data->period);
1602 if (sample_type & PERF_SAMPLE_WEIGHT)
1603 size += sizeof(data->weight);
1605 if (sample_type & PERF_SAMPLE_READ)
1606 size += event->read_size;
1608 if (sample_type & PERF_SAMPLE_DATA_SRC)
1609 size += sizeof(data->data_src.val);
1611 if (sample_type & PERF_SAMPLE_TRANSACTION)
1612 size += sizeof(data->txn);
1614 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1615 size += sizeof(data->phys_addr);
1617 event->header_size = size;
1621 * Called at perf_event creation and when events are attached/detached from a
1624 static void perf_event__header_size(struct perf_event *event)
1626 __perf_event_read_size(event,
1627 event->group_leader->nr_siblings);
1628 __perf_event_header_size(event, event->attr.sample_type);
1631 static void perf_event__id_header_size(struct perf_event *event)
1633 struct perf_sample_data *data;
1634 u64 sample_type = event->attr.sample_type;
1637 if (sample_type & PERF_SAMPLE_TID)
1638 size += sizeof(data->tid_entry);
1640 if (sample_type & PERF_SAMPLE_TIME)
1641 size += sizeof(data->time);
1643 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1644 size += sizeof(data->id);
1646 if (sample_type & PERF_SAMPLE_ID)
1647 size += sizeof(data->id);
1649 if (sample_type & PERF_SAMPLE_STREAM_ID)
1650 size += sizeof(data->stream_id);
1652 if (sample_type & PERF_SAMPLE_CPU)
1653 size += sizeof(data->cpu_entry);
1655 event->id_header_size = size;
1658 static bool perf_event_validate_size(struct perf_event *event)
1661 * The values computed here will be over-written when we actually
1664 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1665 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1666 perf_event__id_header_size(event);
1669 * Sum the lot; should not exceed the 64k limit we have on records.
1670 * Conservative limit to allow for callchains and other variable fields.
1672 if (event->read_size + event->header_size +
1673 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1679 static void perf_group_attach(struct perf_event *event)
1681 struct perf_event *group_leader = event->group_leader, *pos;
1683 lockdep_assert_held(&event->ctx->lock);
1686 * We can have double attach due to group movement in perf_event_open.
1688 if (event->attach_state & PERF_ATTACH_GROUP)
1691 event->attach_state |= PERF_ATTACH_GROUP;
1693 if (group_leader == event)
1696 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1698 group_leader->group_caps &= event->event_caps;
1700 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1701 group_leader->nr_siblings++;
1702 group_leader->group_generation++;
1704 perf_event__header_size(group_leader);
1706 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1707 perf_event__header_size(pos);
1711 * Remove a event from the lists for its context.
1712 * Must be called with ctx->mutex and ctx->lock held.
1715 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1717 WARN_ON_ONCE(event->ctx != ctx);
1718 lockdep_assert_held(&ctx->lock);
1721 * We can have double detach due to exit/hot-unplug + close.
1723 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1726 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1728 list_update_cgroup_event(event, ctx, false);
1731 if (event->attr.inherit_stat)
1734 list_del_rcu(&event->event_entry);
1736 if (event->group_leader == event)
1737 list_del_init(&event->group_entry);
1739 update_group_times(event);
1742 * If event was in error state, then keep it
1743 * that way, otherwise bogus counts will be
1744 * returned on read(). The only way to get out
1745 * of error state is by explicit re-enabling
1748 if (event->state > PERF_EVENT_STATE_OFF)
1749 event->state = PERF_EVENT_STATE_OFF;
1754 static void perf_group_detach(struct perf_event *event)
1756 struct perf_event *sibling, *tmp;
1757 struct list_head *list = NULL;
1759 lockdep_assert_held(&event->ctx->lock);
1762 * We can have double detach due to exit/hot-unplug + close.
1764 if (!(event->attach_state & PERF_ATTACH_GROUP))
1767 event->attach_state &= ~PERF_ATTACH_GROUP;
1770 * If this is a sibling, remove it from its group.
1772 if (event->group_leader != event) {
1773 list_del_init(&event->group_entry);
1774 event->group_leader->nr_siblings--;
1775 event->group_leader->group_generation++;
1779 if (!list_empty(&event->group_entry))
1780 list = &event->group_entry;
1783 * If this was a group event with sibling events then
1784 * upgrade the siblings to singleton events by adding them
1785 * to whatever list we are on.
1787 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1789 list_move_tail(&sibling->group_entry, list);
1790 sibling->group_leader = sibling;
1792 /* Inherit group flags from the previous leader */
1793 sibling->group_caps = event->group_caps;
1795 WARN_ON_ONCE(sibling->ctx != event->ctx);
1799 perf_event__header_size(event->group_leader);
1801 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1802 perf_event__header_size(tmp);
1805 static bool is_orphaned_event(struct perf_event *event)
1807 return event->state == PERF_EVENT_STATE_DEAD;
1810 static inline int __pmu_filter_match(struct perf_event *event)
1812 struct pmu *pmu = event->pmu;
1813 return pmu->filter_match ? pmu->filter_match(event) : 1;
1817 * Check whether we should attempt to schedule an event group based on
1818 * PMU-specific filtering. An event group can consist of HW and SW events,
1819 * potentially with a SW leader, so we must check all the filters, to
1820 * determine whether a group is schedulable:
1822 static inline int pmu_filter_match(struct perf_event *event)
1824 struct perf_event *child;
1826 if (!__pmu_filter_match(event))
1829 list_for_each_entry(child, &event->sibling_list, group_entry) {
1830 if (!__pmu_filter_match(child))
1838 event_filter_match(struct perf_event *event)
1840 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1841 perf_cgroup_match(event) && pmu_filter_match(event);
1845 event_sched_out(struct perf_event *event,
1846 struct perf_cpu_context *cpuctx,
1847 struct perf_event_context *ctx)
1849 u64 tstamp = perf_event_time(event);
1852 WARN_ON_ONCE(event->ctx != ctx);
1853 lockdep_assert_held(&ctx->lock);
1856 * An event which could not be activated because of
1857 * filter mismatch still needs to have its timings
1858 * maintained, otherwise bogus information is return
1859 * via read() for time_enabled, time_running:
1861 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1862 !event_filter_match(event)) {
1863 delta = tstamp - event->tstamp_stopped;
1864 event->tstamp_running += delta;
1865 event->tstamp_stopped = tstamp;
1868 if (event->state != PERF_EVENT_STATE_ACTIVE)
1871 perf_pmu_disable(event->pmu);
1873 event->tstamp_stopped = tstamp;
1874 event->pmu->del(event, 0);
1876 event->state = PERF_EVENT_STATE_INACTIVE;
1877 if (event->pending_disable) {
1878 event->pending_disable = 0;
1879 event->state = PERF_EVENT_STATE_OFF;
1882 if (!is_software_event(event))
1883 cpuctx->active_oncpu--;
1884 if (!--ctx->nr_active)
1885 perf_event_ctx_deactivate(ctx);
1886 if (event->attr.freq && event->attr.sample_freq)
1888 if (event->attr.exclusive || !cpuctx->active_oncpu)
1889 cpuctx->exclusive = 0;
1891 perf_pmu_enable(event->pmu);
1895 group_sched_out(struct perf_event *group_event,
1896 struct perf_cpu_context *cpuctx,
1897 struct perf_event_context *ctx)
1899 struct perf_event *event;
1900 int state = group_event->state;
1902 perf_pmu_disable(ctx->pmu);
1904 event_sched_out(group_event, cpuctx, ctx);
1907 * Schedule out siblings (if any):
1909 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1910 event_sched_out(event, cpuctx, ctx);
1912 perf_pmu_enable(ctx->pmu);
1914 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1915 cpuctx->exclusive = 0;
1918 #define DETACH_GROUP 0x01UL
1921 * Cross CPU call to remove a performance event
1923 * We disable the event on the hardware level first. After that we
1924 * remove it from the context list.
1927 __perf_remove_from_context(struct perf_event *event,
1928 struct perf_cpu_context *cpuctx,
1929 struct perf_event_context *ctx,
1932 unsigned long flags = (unsigned long)info;
1934 event_sched_out(event, cpuctx, ctx);
1935 if (flags & DETACH_GROUP)
1936 perf_group_detach(event);
1937 list_del_event(event, ctx);
1939 if (!ctx->nr_events && ctx->is_active) {
1942 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1943 cpuctx->task_ctx = NULL;
1949 * Remove the event from a task's (or a CPU's) list of events.
1951 * If event->ctx is a cloned context, callers must make sure that
1952 * every task struct that event->ctx->task could possibly point to
1953 * remains valid. This is OK when called from perf_release since
1954 * that only calls us on the top-level context, which can't be a clone.
1955 * When called from perf_event_exit_task, it's OK because the
1956 * context has been detached from its task.
1958 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1960 struct perf_event_context *ctx = event->ctx;
1962 lockdep_assert_held(&ctx->mutex);
1964 event_function_call(event, __perf_remove_from_context, (void *)flags);
1967 * The above event_function_call() can NO-OP when it hits
1968 * TASK_TOMBSTONE. In that case we must already have been detached
1969 * from the context (by perf_event_exit_event()) but the grouping
1970 * might still be in-tact.
1972 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1973 if ((flags & DETACH_GROUP) &&
1974 (event->attach_state & PERF_ATTACH_GROUP)) {
1976 * Since in that case we cannot possibly be scheduled, simply
1979 raw_spin_lock_irq(&ctx->lock);
1980 perf_group_detach(event);
1981 raw_spin_unlock_irq(&ctx->lock);
1986 * Cross CPU call to disable a performance event
1988 static void __perf_event_disable(struct perf_event *event,
1989 struct perf_cpu_context *cpuctx,
1990 struct perf_event_context *ctx,
1993 if (event->state < PERF_EVENT_STATE_INACTIVE)
1996 update_context_time(ctx);
1997 update_cgrp_time_from_event(event);
1998 update_group_times(event);
1999 if (event == event->group_leader)
2000 group_sched_out(event, cpuctx, ctx);
2002 event_sched_out(event, cpuctx, ctx);
2003 event->state = PERF_EVENT_STATE_OFF;
2009 * If event->ctx is a cloned context, callers must make sure that
2010 * every task struct that event->ctx->task could possibly point to
2011 * remains valid. This condition is satisifed when called through
2012 * perf_event_for_each_child or perf_event_for_each because they
2013 * hold the top-level event's child_mutex, so any descendant that
2014 * goes to exit will block in perf_event_exit_event().
2016 * When called from perf_pending_event it's OK because event->ctx
2017 * is the current context on this CPU and preemption is disabled,
2018 * hence we can't get into perf_event_task_sched_out for this context.
2020 static void _perf_event_disable(struct perf_event *event)
2022 struct perf_event_context *ctx = event->ctx;
2024 raw_spin_lock_irq(&ctx->lock);
2025 if (event->state <= PERF_EVENT_STATE_OFF) {
2026 raw_spin_unlock_irq(&ctx->lock);
2029 raw_spin_unlock_irq(&ctx->lock);
2031 event_function_call(event, __perf_event_disable, NULL);
2034 void perf_event_disable_local(struct perf_event *event)
2036 event_function_local(event, __perf_event_disable, NULL);
2040 * Strictly speaking kernel users cannot create groups and therefore this
2041 * interface does not need the perf_event_ctx_lock() magic.
2043 void perf_event_disable(struct perf_event *event)
2045 struct perf_event_context *ctx;
2047 ctx = perf_event_ctx_lock(event);
2048 _perf_event_disable(event);
2049 perf_event_ctx_unlock(event, ctx);
2051 EXPORT_SYMBOL_GPL(perf_event_disable);
2053 void perf_event_disable_inatomic(struct perf_event *event)
2055 event->pending_disable = 1;
2056 irq_work_queue(&event->pending);
2059 static void perf_set_shadow_time(struct perf_event *event,
2060 struct perf_event_context *ctx,
2064 * use the correct time source for the time snapshot
2066 * We could get by without this by leveraging the
2067 * fact that to get to this function, the caller
2068 * has most likely already called update_context_time()
2069 * and update_cgrp_time_xx() and thus both timestamp
2070 * are identical (or very close). Given that tstamp is,
2071 * already adjusted for cgroup, we could say that:
2072 * tstamp - ctx->timestamp
2074 * tstamp - cgrp->timestamp.
2076 * Then, in perf_output_read(), the calculation would
2077 * work with no changes because:
2078 * - event is guaranteed scheduled in
2079 * - no scheduled out in between
2080 * - thus the timestamp would be the same
2082 * But this is a bit hairy.
2084 * So instead, we have an explicit cgroup call to remain
2085 * within the time time source all along. We believe it
2086 * is cleaner and simpler to understand.
2088 if (is_cgroup_event(event))
2089 perf_cgroup_set_shadow_time(event, tstamp);
2091 event->shadow_ctx_time = tstamp - ctx->timestamp;
2094 #define MAX_INTERRUPTS (~0ULL)
2096 static void perf_log_throttle(struct perf_event *event, int enable);
2097 static void perf_log_itrace_start(struct perf_event *event);
2100 event_sched_in(struct perf_event *event,
2101 struct perf_cpu_context *cpuctx,
2102 struct perf_event_context *ctx)
2104 u64 tstamp = perf_event_time(event);
2107 lockdep_assert_held(&ctx->lock);
2109 if (event->state <= PERF_EVENT_STATE_OFF)
2112 WRITE_ONCE(event->oncpu, smp_processor_id());
2114 * Order event::oncpu write to happen before the ACTIVE state
2118 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2121 * Unthrottle events, since we scheduled we might have missed several
2122 * ticks already, also for a heavily scheduling task there is little
2123 * guarantee it'll get a tick in a timely manner.
2125 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2126 perf_log_throttle(event, 1);
2127 event->hw.interrupts = 0;
2131 * The new state must be visible before we turn it on in the hardware:
2135 perf_pmu_disable(event->pmu);
2137 perf_set_shadow_time(event, ctx, tstamp);
2139 perf_log_itrace_start(event);
2141 if (event->pmu->add(event, PERF_EF_START)) {
2142 event->state = PERF_EVENT_STATE_INACTIVE;
2148 event->tstamp_running += tstamp - event->tstamp_stopped;
2150 if (!is_software_event(event))
2151 cpuctx->active_oncpu++;
2152 if (!ctx->nr_active++)
2153 perf_event_ctx_activate(ctx);
2154 if (event->attr.freq && event->attr.sample_freq)
2157 if (event->attr.exclusive)
2158 cpuctx->exclusive = 1;
2161 perf_pmu_enable(event->pmu);
2167 group_sched_in(struct perf_event *group_event,
2168 struct perf_cpu_context *cpuctx,
2169 struct perf_event_context *ctx)
2171 struct perf_event *event, *partial_group = NULL;
2172 struct pmu *pmu = ctx->pmu;
2173 u64 now = ctx->time;
2174 bool simulate = false;
2176 if (group_event->state == PERF_EVENT_STATE_OFF)
2179 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2181 if (event_sched_in(group_event, cpuctx, ctx)) {
2182 pmu->cancel_txn(pmu);
2183 perf_mux_hrtimer_restart(cpuctx);
2188 * Schedule in siblings as one group (if any):
2190 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2191 if (event_sched_in(event, cpuctx, ctx)) {
2192 partial_group = event;
2197 if (!pmu->commit_txn(pmu))
2202 * Groups can be scheduled in as one unit only, so undo any
2203 * partial group before returning:
2204 * The events up to the failed event are scheduled out normally,
2205 * tstamp_stopped will be updated.
2207 * The failed events and the remaining siblings need to have
2208 * their timings updated as if they had gone thru event_sched_in()
2209 * and event_sched_out(). This is required to get consistent timings
2210 * across the group. This also takes care of the case where the group
2211 * could never be scheduled by ensuring tstamp_stopped is set to mark
2212 * the time the event was actually stopped, such that time delta
2213 * calculation in update_event_times() is correct.
2215 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2216 if (event == partial_group)
2220 event->tstamp_running += now - event->tstamp_stopped;
2221 event->tstamp_stopped = now;
2223 event_sched_out(event, cpuctx, ctx);
2226 event_sched_out(group_event, cpuctx, ctx);
2228 pmu->cancel_txn(pmu);
2230 perf_mux_hrtimer_restart(cpuctx);
2236 * Work out whether we can put this event group on the CPU now.
2238 static int group_can_go_on(struct perf_event *event,
2239 struct perf_cpu_context *cpuctx,
2243 * Groups consisting entirely of software events can always go on.
2245 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2248 * If an exclusive group is already on, no other hardware
2251 if (cpuctx->exclusive)
2254 * If this group is exclusive and there are already
2255 * events on the CPU, it can't go on.
2257 if (event->attr.exclusive && cpuctx->active_oncpu)
2260 * Otherwise, try to add it if all previous groups were able
2267 * Complement to update_event_times(). This computes the tstamp_* values to
2268 * continue 'enabled' state from @now, and effectively discards the time
2269 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2270 * just switched (context) time base).
2272 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2273 * cannot have been scheduled in yet. And going into INACTIVE state means
2274 * '@event->tstamp_stopped = @now'.
2276 * Thus given the rules of update_event_times():
2278 * total_time_enabled = tstamp_stopped - tstamp_enabled
2279 * total_time_running = tstamp_stopped - tstamp_running
2281 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2284 static void __perf_event_enable_time(struct perf_event *event, u64 now)
2286 WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE);
2288 event->tstamp_stopped = now;
2289 event->tstamp_enabled = now - event->total_time_enabled;
2290 event->tstamp_running = now - event->total_time_running;
2293 static void add_event_to_ctx(struct perf_event *event,
2294 struct perf_event_context *ctx)
2296 u64 tstamp = perf_event_time(event);
2298 list_add_event(event, ctx);
2299 perf_group_attach(event);
2301 * We can be called with event->state == STATE_OFF when we create with
2302 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2304 if (event->state == PERF_EVENT_STATE_INACTIVE)
2305 __perf_event_enable_time(event, tstamp);
2308 static void ctx_sched_out(struct perf_event_context *ctx,
2309 struct perf_cpu_context *cpuctx,
2310 enum event_type_t event_type);
2312 ctx_sched_in(struct perf_event_context *ctx,
2313 struct perf_cpu_context *cpuctx,
2314 enum event_type_t event_type,
2315 struct task_struct *task);
2317 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2318 struct perf_event_context *ctx,
2319 enum event_type_t event_type)
2321 if (!cpuctx->task_ctx)
2324 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2327 ctx_sched_out(ctx, cpuctx, event_type);
2330 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2331 struct perf_event_context *ctx,
2332 struct task_struct *task)
2334 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2336 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2337 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2339 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2343 * We want to maintain the following priority of scheduling:
2344 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2345 * - task pinned (EVENT_PINNED)
2346 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2347 * - task flexible (EVENT_FLEXIBLE).
2349 * In order to avoid unscheduling and scheduling back in everything every
2350 * time an event is added, only do it for the groups of equal priority and
2353 * This can be called after a batch operation on task events, in which case
2354 * event_type is a bit mask of the types of events involved. For CPU events,
2355 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2357 static void ctx_resched(struct perf_cpu_context *cpuctx,
2358 struct perf_event_context *task_ctx,
2359 enum event_type_t event_type)
2361 enum event_type_t ctx_event_type;
2362 bool cpu_event = !!(event_type & EVENT_CPU);
2365 * If pinned groups are involved, flexible groups also need to be
2368 if (event_type & EVENT_PINNED)
2369 event_type |= EVENT_FLEXIBLE;
2371 ctx_event_type = event_type & EVENT_ALL;
2373 perf_pmu_disable(cpuctx->ctx.pmu);
2375 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2378 * Decide which cpu ctx groups to schedule out based on the types
2379 * of events that caused rescheduling:
2380 * - EVENT_CPU: schedule out corresponding groups;
2381 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2382 * - otherwise, do nothing more.
2385 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2386 else if (ctx_event_type & EVENT_PINNED)
2387 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2389 perf_event_sched_in(cpuctx, task_ctx, current);
2390 perf_pmu_enable(cpuctx->ctx.pmu);
2394 * Cross CPU call to install and enable a performance event
2396 * Very similar to remote_function() + event_function() but cannot assume that
2397 * things like ctx->is_active and cpuctx->task_ctx are set.
2399 static int __perf_install_in_context(void *info)
2401 struct perf_event *event = info;
2402 struct perf_event_context *ctx = event->ctx;
2403 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2404 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2405 bool reprogram = true;
2408 raw_spin_lock(&cpuctx->ctx.lock);
2410 raw_spin_lock(&ctx->lock);
2413 reprogram = (ctx->task == current);
2416 * If the task is running, it must be running on this CPU,
2417 * otherwise we cannot reprogram things.
2419 * If its not running, we don't care, ctx->lock will
2420 * serialize against it becoming runnable.
2422 if (task_curr(ctx->task) && !reprogram) {
2427 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2428 } else if (task_ctx) {
2429 raw_spin_lock(&task_ctx->lock);
2432 #ifdef CONFIG_CGROUP_PERF
2433 if (is_cgroup_event(event)) {
2435 * If the current cgroup doesn't match the event's
2436 * cgroup, we should not try to schedule it.
2438 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2439 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2440 event->cgrp->css.cgroup);
2445 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2446 add_event_to_ctx(event, ctx);
2447 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2449 add_event_to_ctx(event, ctx);
2453 perf_ctx_unlock(cpuctx, task_ctx);
2459 * Attach a performance event to a context.
2461 * Very similar to event_function_call, see comment there.
2464 perf_install_in_context(struct perf_event_context *ctx,
2465 struct perf_event *event,
2468 struct task_struct *task = READ_ONCE(ctx->task);
2470 lockdep_assert_held(&ctx->mutex);
2472 if (event->cpu != -1)
2476 * Ensures that if we can observe event->ctx, both the event and ctx
2477 * will be 'complete'. See perf_iterate_sb_cpu().
2479 smp_store_release(&event->ctx, ctx);
2482 cpu_function_call(cpu, __perf_install_in_context, event);
2487 * Should not happen, we validate the ctx is still alive before calling.
2489 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2493 * Installing events is tricky because we cannot rely on ctx->is_active
2494 * to be set in case this is the nr_events 0 -> 1 transition.
2496 * Instead we use task_curr(), which tells us if the task is running.
2497 * However, since we use task_curr() outside of rq::lock, we can race
2498 * against the actual state. This means the result can be wrong.
2500 * If we get a false positive, we retry, this is harmless.
2502 * If we get a false negative, things are complicated. If we are after
2503 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2504 * value must be correct. If we're before, it doesn't matter since
2505 * perf_event_context_sched_in() will program the counter.
2507 * However, this hinges on the remote context switch having observed
2508 * our task->perf_event_ctxp[] store, such that it will in fact take
2509 * ctx::lock in perf_event_context_sched_in().
2511 * We do this by task_function_call(), if the IPI fails to hit the task
2512 * we know any future context switch of task must see the
2513 * perf_event_ctpx[] store.
2517 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2518 * task_cpu() load, such that if the IPI then does not find the task
2519 * running, a future context switch of that task must observe the
2524 if (!task_function_call(task, __perf_install_in_context, event))
2527 raw_spin_lock_irq(&ctx->lock);
2529 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2531 * Cannot happen because we already checked above (which also
2532 * cannot happen), and we hold ctx->mutex, which serializes us
2533 * against perf_event_exit_task_context().
2535 raw_spin_unlock_irq(&ctx->lock);
2539 * If the task is not running, ctx->lock will avoid it becoming so,
2540 * thus we can safely install the event.
2542 if (task_curr(task)) {
2543 raw_spin_unlock_irq(&ctx->lock);
2546 add_event_to_ctx(event, ctx);
2547 raw_spin_unlock_irq(&ctx->lock);
2551 * Put a event into inactive state and update time fields.
2552 * Enabling the leader of a group effectively enables all
2553 * the group members that aren't explicitly disabled, so we
2554 * have to update their ->tstamp_enabled also.
2555 * Note: this works for group members as well as group leaders
2556 * since the non-leader members' sibling_lists will be empty.
2558 static void __perf_event_mark_enabled(struct perf_event *event)
2560 struct perf_event *sub;
2561 u64 tstamp = perf_event_time(event);
2563 event->state = PERF_EVENT_STATE_INACTIVE;
2564 __perf_event_enable_time(event, tstamp);
2565 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2566 /* XXX should not be > INACTIVE if event isn't */
2567 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2568 __perf_event_enable_time(sub, tstamp);
2573 * Cross CPU call to enable a performance event
2575 static void __perf_event_enable(struct perf_event *event,
2576 struct perf_cpu_context *cpuctx,
2577 struct perf_event_context *ctx,
2580 struct perf_event *leader = event->group_leader;
2581 struct perf_event_context *task_ctx;
2583 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2584 event->state <= PERF_EVENT_STATE_ERROR)
2588 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2590 __perf_event_mark_enabled(event);
2592 if (!ctx->is_active)
2595 if (!event_filter_match(event)) {
2596 if (is_cgroup_event(event))
2597 perf_cgroup_defer_enabled(event);
2598 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2603 * If the event is in a group and isn't the group leader,
2604 * then don't put it on unless the group is on.
2606 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2607 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2611 task_ctx = cpuctx->task_ctx;
2613 WARN_ON_ONCE(task_ctx != ctx);
2615 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2621 * If event->ctx is a cloned context, callers must make sure that
2622 * every task struct that event->ctx->task could possibly point to
2623 * remains valid. This condition is satisfied when called through
2624 * perf_event_for_each_child or perf_event_for_each as described
2625 * for perf_event_disable.
2627 static void _perf_event_enable(struct perf_event *event)
2629 struct perf_event_context *ctx = event->ctx;
2631 raw_spin_lock_irq(&ctx->lock);
2632 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2633 event->state < PERF_EVENT_STATE_ERROR) {
2634 raw_spin_unlock_irq(&ctx->lock);
2639 * If the event is in error state, clear that first.
2641 * That way, if we see the event in error state below, we know that it
2642 * has gone back into error state, as distinct from the task having
2643 * been scheduled away before the cross-call arrived.
2645 if (event->state == PERF_EVENT_STATE_ERROR)
2646 event->state = PERF_EVENT_STATE_OFF;
2647 raw_spin_unlock_irq(&ctx->lock);
2649 event_function_call(event, __perf_event_enable, NULL);
2653 * See perf_event_disable();
2655 void perf_event_enable(struct perf_event *event)
2657 struct perf_event_context *ctx;
2659 ctx = perf_event_ctx_lock(event);
2660 _perf_event_enable(event);
2661 perf_event_ctx_unlock(event, ctx);
2663 EXPORT_SYMBOL_GPL(perf_event_enable);
2665 struct stop_event_data {
2666 struct perf_event *event;
2667 unsigned int restart;
2670 static int __perf_event_stop(void *info)
2672 struct stop_event_data *sd = info;
2673 struct perf_event *event = sd->event;
2675 /* if it's already INACTIVE, do nothing */
2676 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2679 /* matches smp_wmb() in event_sched_in() */
2683 * There is a window with interrupts enabled before we get here,
2684 * so we need to check again lest we try to stop another CPU's event.
2686 if (READ_ONCE(event->oncpu) != smp_processor_id())
2689 event->pmu->stop(event, PERF_EF_UPDATE);
2692 * May race with the actual stop (through perf_pmu_output_stop()),
2693 * but it is only used for events with AUX ring buffer, and such
2694 * events will refuse to restart because of rb::aux_mmap_count==0,
2695 * see comments in perf_aux_output_begin().
2697 * Since this is happening on a event-local CPU, no trace is lost
2701 event->pmu->start(event, 0);
2706 static int perf_event_stop(struct perf_event *event, int restart)
2708 struct stop_event_data sd = {
2715 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2718 /* matches smp_wmb() in event_sched_in() */
2722 * We only want to restart ACTIVE events, so if the event goes
2723 * inactive here (event->oncpu==-1), there's nothing more to do;
2724 * fall through with ret==-ENXIO.
2726 ret = cpu_function_call(READ_ONCE(event->oncpu),
2727 __perf_event_stop, &sd);
2728 } while (ret == -EAGAIN);
2734 * In order to contain the amount of racy and tricky in the address filter
2735 * configuration management, it is a two part process:
2737 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2738 * we update the addresses of corresponding vmas in
2739 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2740 * (p2) when an event is scheduled in (pmu::add), it calls
2741 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2742 * if the generation has changed since the previous call.
2744 * If (p1) happens while the event is active, we restart it to force (p2).
2746 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2747 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2749 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2750 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2752 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2755 void perf_event_addr_filters_sync(struct perf_event *event)
2757 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2759 if (!has_addr_filter(event))
2762 raw_spin_lock(&ifh->lock);
2763 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2764 event->pmu->addr_filters_sync(event);
2765 event->hw.addr_filters_gen = event->addr_filters_gen;
2767 raw_spin_unlock(&ifh->lock);
2769 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2771 static int _perf_event_refresh(struct perf_event *event, int refresh)
2774 * not supported on inherited events
2776 if (event->attr.inherit || !is_sampling_event(event))
2779 atomic_add(refresh, &event->event_limit);
2780 _perf_event_enable(event);
2786 * See perf_event_disable()
2788 int perf_event_refresh(struct perf_event *event, int refresh)
2790 struct perf_event_context *ctx;
2793 ctx = perf_event_ctx_lock(event);
2794 ret = _perf_event_refresh(event, refresh);
2795 perf_event_ctx_unlock(event, ctx);
2799 EXPORT_SYMBOL_GPL(perf_event_refresh);
2801 static void ctx_sched_out(struct perf_event_context *ctx,
2802 struct perf_cpu_context *cpuctx,
2803 enum event_type_t event_type)
2805 int is_active = ctx->is_active;
2806 struct perf_event *event;
2808 lockdep_assert_held(&ctx->lock);
2810 if (likely(!ctx->nr_events)) {
2812 * See __perf_remove_from_context().
2814 WARN_ON_ONCE(ctx->is_active);
2816 WARN_ON_ONCE(cpuctx->task_ctx);
2820 ctx->is_active &= ~event_type;
2821 if (!(ctx->is_active & EVENT_ALL))
2825 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2826 if (!ctx->is_active)
2827 cpuctx->task_ctx = NULL;
2831 * Always update time if it was set; not only when it changes.
2832 * Otherwise we can 'forget' to update time for any but the last
2833 * context we sched out. For example:
2835 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2836 * ctx_sched_out(.event_type = EVENT_PINNED)
2838 * would only update time for the pinned events.
2840 if (is_active & EVENT_TIME) {
2841 /* update (and stop) ctx time */
2842 update_context_time(ctx);
2843 update_cgrp_time_from_cpuctx(cpuctx);
2846 is_active ^= ctx->is_active; /* changed bits */
2848 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2851 perf_pmu_disable(ctx->pmu);
2852 if (is_active & EVENT_PINNED) {
2853 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2854 group_sched_out(event, cpuctx, ctx);
2857 if (is_active & EVENT_FLEXIBLE) {
2858 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2859 group_sched_out(event, cpuctx, ctx);
2861 perf_pmu_enable(ctx->pmu);
2865 * Test whether two contexts are equivalent, i.e. whether they have both been
2866 * cloned from the same version of the same context.
2868 * Equivalence is measured using a generation number in the context that is
2869 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2870 * and list_del_event().
2872 static int context_equiv(struct perf_event_context *ctx1,
2873 struct perf_event_context *ctx2)
2875 lockdep_assert_held(&ctx1->lock);
2876 lockdep_assert_held(&ctx2->lock);
2878 /* Pinning disables the swap optimization */
2879 if (ctx1->pin_count || ctx2->pin_count)
2882 /* If ctx1 is the parent of ctx2 */
2883 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2886 /* If ctx2 is the parent of ctx1 */
2887 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2891 * If ctx1 and ctx2 have the same parent; we flatten the parent
2892 * hierarchy, see perf_event_init_context().
2894 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2895 ctx1->parent_gen == ctx2->parent_gen)
2902 static void __perf_event_sync_stat(struct perf_event *event,
2903 struct perf_event *next_event)
2907 if (!event->attr.inherit_stat)
2911 * Update the event value, we cannot use perf_event_read()
2912 * because we're in the middle of a context switch and have IRQs
2913 * disabled, which upsets smp_call_function_single(), however
2914 * we know the event must be on the current CPU, therefore we
2915 * don't need to use it.
2917 switch (event->state) {
2918 case PERF_EVENT_STATE_ACTIVE:
2919 event->pmu->read(event);
2922 case PERF_EVENT_STATE_INACTIVE:
2923 update_event_times(event);
2931 * In order to keep per-task stats reliable we need to flip the event
2932 * values when we flip the contexts.
2934 value = local64_read(&next_event->count);
2935 value = local64_xchg(&event->count, value);
2936 local64_set(&next_event->count, value);
2938 swap(event->total_time_enabled, next_event->total_time_enabled);
2939 swap(event->total_time_running, next_event->total_time_running);
2942 * Since we swizzled the values, update the user visible data too.
2944 perf_event_update_userpage(event);
2945 perf_event_update_userpage(next_event);
2948 static void perf_event_sync_stat(struct perf_event_context *ctx,
2949 struct perf_event_context *next_ctx)
2951 struct perf_event *event, *next_event;
2956 update_context_time(ctx);
2958 event = list_first_entry(&ctx->event_list,
2959 struct perf_event, event_entry);
2961 next_event = list_first_entry(&next_ctx->event_list,
2962 struct perf_event, event_entry);
2964 while (&event->event_entry != &ctx->event_list &&
2965 &next_event->event_entry != &next_ctx->event_list) {
2967 __perf_event_sync_stat(event, next_event);
2969 event = list_next_entry(event, event_entry);
2970 next_event = list_next_entry(next_event, event_entry);
2974 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2975 struct task_struct *next)
2977 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2978 struct perf_event_context *next_ctx;
2979 struct perf_event_context *parent, *next_parent;
2980 struct perf_cpu_context *cpuctx;
2986 cpuctx = __get_cpu_context(ctx);
2987 if (!cpuctx->task_ctx)
2991 next_ctx = next->perf_event_ctxp[ctxn];
2995 parent = rcu_dereference(ctx->parent_ctx);
2996 next_parent = rcu_dereference(next_ctx->parent_ctx);
2998 /* If neither context have a parent context; they cannot be clones. */
2999 if (!parent && !next_parent)
3002 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3004 * Looks like the two contexts are clones, so we might be
3005 * able to optimize the context switch. We lock both
3006 * contexts and check that they are clones under the
3007 * lock (including re-checking that neither has been
3008 * uncloned in the meantime). It doesn't matter which
3009 * order we take the locks because no other cpu could
3010 * be trying to lock both of these tasks.
3012 raw_spin_lock(&ctx->lock);
3013 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3014 if (context_equiv(ctx, next_ctx)) {
3015 WRITE_ONCE(ctx->task, next);
3016 WRITE_ONCE(next_ctx->task, task);
3018 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3021 * RCU_INIT_POINTER here is safe because we've not
3022 * modified the ctx and the above modification of
3023 * ctx->task and ctx->task_ctx_data are immaterial
3024 * since those values are always verified under
3025 * ctx->lock which we're now holding.
3027 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3028 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3032 perf_event_sync_stat(ctx, next_ctx);
3034 raw_spin_unlock(&next_ctx->lock);
3035 raw_spin_unlock(&ctx->lock);
3041 raw_spin_lock(&ctx->lock);
3042 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3043 raw_spin_unlock(&ctx->lock);
3047 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3049 void perf_sched_cb_dec(struct pmu *pmu)
3051 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3053 this_cpu_dec(perf_sched_cb_usages);
3055 if (!--cpuctx->sched_cb_usage)
3056 list_del(&cpuctx->sched_cb_entry);
3060 void perf_sched_cb_inc(struct pmu *pmu)
3062 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3064 if (!cpuctx->sched_cb_usage++)
3065 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3067 this_cpu_inc(perf_sched_cb_usages);
3071 * This function provides the context switch callback to the lower code
3072 * layer. It is invoked ONLY when the context switch callback is enabled.
3074 * This callback is relevant even to per-cpu events; for example multi event
3075 * PEBS requires this to provide PID/TID information. This requires we flush
3076 * all queued PEBS records before we context switch to a new task.
3078 static void perf_pmu_sched_task(struct task_struct *prev,
3079 struct task_struct *next,
3082 struct perf_cpu_context *cpuctx;
3088 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3089 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3091 if (WARN_ON_ONCE(!pmu->sched_task))
3094 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3095 perf_pmu_disable(pmu);
3097 pmu->sched_task(cpuctx->task_ctx, sched_in);
3099 perf_pmu_enable(pmu);
3100 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3104 static void perf_event_switch(struct task_struct *task,
3105 struct task_struct *next_prev, bool sched_in);
3107 #define for_each_task_context_nr(ctxn) \
3108 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3111 * Called from scheduler to remove the events of the current task,
3112 * with interrupts disabled.
3114 * We stop each event and update the event value in event->count.
3116 * This does not protect us against NMI, but disable()
3117 * sets the disabled bit in the control field of event _before_
3118 * accessing the event control register. If a NMI hits, then it will
3119 * not restart the event.
3121 void __perf_event_task_sched_out(struct task_struct *task,
3122 struct task_struct *next)
3126 if (__this_cpu_read(perf_sched_cb_usages))
3127 perf_pmu_sched_task(task, next, false);
3129 if (atomic_read(&nr_switch_events))
3130 perf_event_switch(task, next, false);
3132 for_each_task_context_nr(ctxn)
3133 perf_event_context_sched_out(task, ctxn, next);
3136 * if cgroup events exist on this CPU, then we need
3137 * to check if we have to switch out PMU state.
3138 * cgroup event are system-wide mode only
3140 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3141 perf_cgroup_sched_out(task, next);
3145 * Called with IRQs disabled
3147 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3148 enum event_type_t event_type)
3150 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3154 ctx_pinned_sched_in(struct perf_event_context *ctx,
3155 struct perf_cpu_context *cpuctx)
3157 struct perf_event *event;
3159 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3160 if (event->state <= PERF_EVENT_STATE_OFF)
3162 if (!event_filter_match(event))
3165 /* may need to reset tstamp_enabled */
3166 if (is_cgroup_event(event))
3167 perf_cgroup_mark_enabled(event, ctx);
3169 if (group_can_go_on(event, cpuctx, 1))
3170 group_sched_in(event, cpuctx, ctx);
3173 * If this pinned group hasn't been scheduled,
3174 * put it in error state.
3176 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3177 update_group_times(event);
3178 event->state = PERF_EVENT_STATE_ERROR;
3184 ctx_flexible_sched_in(struct perf_event_context *ctx,
3185 struct perf_cpu_context *cpuctx)
3187 struct perf_event *event;
3190 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3191 /* Ignore events in OFF or ERROR state */
3192 if (event->state <= PERF_EVENT_STATE_OFF)
3195 * Listen to the 'cpu' scheduling filter constraint
3198 if (!event_filter_match(event))
3201 /* may need to reset tstamp_enabled */
3202 if (is_cgroup_event(event))
3203 perf_cgroup_mark_enabled(event, ctx);
3205 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3206 if (group_sched_in(event, cpuctx, ctx))
3213 ctx_sched_in(struct perf_event_context *ctx,
3214 struct perf_cpu_context *cpuctx,
3215 enum event_type_t event_type,
3216 struct task_struct *task)
3218 int is_active = ctx->is_active;
3221 lockdep_assert_held(&ctx->lock);
3223 if (likely(!ctx->nr_events))
3226 ctx->is_active |= (event_type | EVENT_TIME);
3229 cpuctx->task_ctx = ctx;
3231 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3234 is_active ^= ctx->is_active; /* changed bits */
3236 if (is_active & EVENT_TIME) {
3237 /* start ctx time */
3239 ctx->timestamp = now;
3240 perf_cgroup_set_timestamp(task, ctx);
3244 * First go through the list and put on any pinned groups
3245 * in order to give them the best chance of going on.
3247 if (is_active & EVENT_PINNED)
3248 ctx_pinned_sched_in(ctx, cpuctx);
3250 /* Then walk through the lower prio flexible groups */
3251 if (is_active & EVENT_FLEXIBLE)
3252 ctx_flexible_sched_in(ctx, cpuctx);
3255 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3256 enum event_type_t event_type,
3257 struct task_struct *task)
3259 struct perf_event_context *ctx = &cpuctx->ctx;
3261 ctx_sched_in(ctx, cpuctx, event_type, task);
3264 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3265 struct task_struct *task)
3267 struct perf_cpu_context *cpuctx;
3269 cpuctx = __get_cpu_context(ctx);
3270 if (cpuctx->task_ctx == ctx)
3273 perf_ctx_lock(cpuctx, ctx);
3275 * We must check ctx->nr_events while holding ctx->lock, such
3276 * that we serialize against perf_install_in_context().
3278 if (!ctx->nr_events)
3281 perf_pmu_disable(ctx->pmu);
3283 * We want to keep the following priority order:
3284 * cpu pinned (that don't need to move), task pinned,
3285 * cpu flexible, task flexible.
3287 * However, if task's ctx is not carrying any pinned
3288 * events, no need to flip the cpuctx's events around.
3290 if (!list_empty(&ctx->pinned_groups))
3291 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3292 perf_event_sched_in(cpuctx, ctx, task);
3293 perf_pmu_enable(ctx->pmu);
3296 perf_ctx_unlock(cpuctx, ctx);
3300 * Called from scheduler to add the events of the current task
3301 * with interrupts disabled.
3303 * We restore the event value and then enable it.
3305 * This does not protect us against NMI, but enable()
3306 * sets the enabled bit in the control field of event _before_
3307 * accessing the event control register. If a NMI hits, then it will
3308 * keep the event running.
3310 void __perf_event_task_sched_in(struct task_struct *prev,
3311 struct task_struct *task)
3313 struct perf_event_context *ctx;
3317 * If cgroup events exist on this CPU, then we need to check if we have
3318 * to switch in PMU state; cgroup event are system-wide mode only.
3320 * Since cgroup events are CPU events, we must schedule these in before
3321 * we schedule in the task events.
3323 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3324 perf_cgroup_sched_in(prev, task);
3326 for_each_task_context_nr(ctxn) {
3327 ctx = task->perf_event_ctxp[ctxn];
3331 perf_event_context_sched_in(ctx, task);
3334 if (atomic_read(&nr_switch_events))
3335 perf_event_switch(task, prev, true);
3337 if (__this_cpu_read(perf_sched_cb_usages))
3338 perf_pmu_sched_task(prev, task, true);
3341 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3343 u64 frequency = event->attr.sample_freq;
3344 u64 sec = NSEC_PER_SEC;
3345 u64 divisor, dividend;
3347 int count_fls, nsec_fls, frequency_fls, sec_fls;
3349 count_fls = fls64(count);
3350 nsec_fls = fls64(nsec);
3351 frequency_fls = fls64(frequency);
3355 * We got @count in @nsec, with a target of sample_freq HZ
3356 * the target period becomes:
3359 * period = -------------------
3360 * @nsec * sample_freq
3365 * Reduce accuracy by one bit such that @a and @b converge
3366 * to a similar magnitude.
3368 #define REDUCE_FLS(a, b) \
3370 if (a##_fls > b##_fls) { \
3380 * Reduce accuracy until either term fits in a u64, then proceed with
3381 * the other, so that finally we can do a u64/u64 division.
3383 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3384 REDUCE_FLS(nsec, frequency);
3385 REDUCE_FLS(sec, count);
3388 if (count_fls + sec_fls > 64) {
3389 divisor = nsec * frequency;
3391 while (count_fls + sec_fls > 64) {
3392 REDUCE_FLS(count, sec);
3396 dividend = count * sec;
3398 dividend = count * sec;
3400 while (nsec_fls + frequency_fls > 64) {
3401 REDUCE_FLS(nsec, frequency);
3405 divisor = nsec * frequency;
3411 return div64_u64(dividend, divisor);
3414 static DEFINE_PER_CPU(int, perf_throttled_count);
3415 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3417 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3419 struct hw_perf_event *hwc = &event->hw;
3420 s64 period, sample_period;
3423 period = perf_calculate_period(event, nsec, count);
3425 delta = (s64)(period - hwc->sample_period);
3426 delta = (delta + 7) / 8; /* low pass filter */
3428 sample_period = hwc->sample_period + delta;
3433 hwc->sample_period = sample_period;
3435 if (local64_read(&hwc->period_left) > 8*sample_period) {
3437 event->pmu->stop(event, PERF_EF_UPDATE);
3439 local64_set(&hwc->period_left, 0);
3442 event->pmu->start(event, PERF_EF_RELOAD);
3447 * combine freq adjustment with unthrottling to avoid two passes over the
3448 * events. At the same time, make sure, having freq events does not change
3449 * the rate of unthrottling as that would introduce bias.
3451 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3454 struct perf_event *event;
3455 struct hw_perf_event *hwc;
3456 u64 now, period = TICK_NSEC;
3460 * only need to iterate over all events iff:
3461 * - context have events in frequency mode (needs freq adjust)
3462 * - there are events to unthrottle on this cpu
3464 if (!(ctx->nr_freq || needs_unthr))
3467 raw_spin_lock(&ctx->lock);
3468 perf_pmu_disable(ctx->pmu);
3470 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3471 if (event->state != PERF_EVENT_STATE_ACTIVE)
3474 if (!event_filter_match(event))
3477 perf_pmu_disable(event->pmu);
3481 if (hwc->interrupts == MAX_INTERRUPTS) {
3482 hwc->interrupts = 0;
3483 perf_log_throttle(event, 1);
3484 event->pmu->start(event, 0);
3487 if (!event->attr.freq || !event->attr.sample_freq)
3491 * stop the event and update event->count
3493 event->pmu->stop(event, PERF_EF_UPDATE);
3495 now = local64_read(&event->count);
3496 delta = now - hwc->freq_count_stamp;
3497 hwc->freq_count_stamp = now;
3501 * reload only if value has changed
3502 * we have stopped the event so tell that
3503 * to perf_adjust_period() to avoid stopping it
3507 perf_adjust_period(event, period, delta, false);
3509 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3511 perf_pmu_enable(event->pmu);
3514 perf_pmu_enable(ctx->pmu);
3515 raw_spin_unlock(&ctx->lock);
3519 * Round-robin a context's events:
3521 static void rotate_ctx(struct perf_event_context *ctx)
3524 * Rotate the first entry last of non-pinned groups. Rotation might be
3525 * disabled by the inheritance code.
3527 if (!ctx->rotate_disable)
3528 list_rotate_left(&ctx->flexible_groups);
3531 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3533 struct perf_event_context *ctx = NULL;
3536 if (cpuctx->ctx.nr_events) {
3537 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3541 ctx = cpuctx->task_ctx;
3542 if (ctx && ctx->nr_events) {
3543 if (ctx->nr_events != ctx->nr_active)
3550 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3551 perf_pmu_disable(cpuctx->ctx.pmu);
3553 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3555 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3557 rotate_ctx(&cpuctx->ctx);
3561 perf_event_sched_in(cpuctx, ctx, current);
3563 perf_pmu_enable(cpuctx->ctx.pmu);
3564 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3570 void perf_event_task_tick(void)
3572 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3573 struct perf_event_context *ctx, *tmp;
3576 WARN_ON(!irqs_disabled());
3578 __this_cpu_inc(perf_throttled_seq);
3579 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3580 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3582 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3583 perf_adjust_freq_unthr_context(ctx, throttled);
3586 static int event_enable_on_exec(struct perf_event *event,
3587 struct perf_event_context *ctx)
3589 if (!event->attr.enable_on_exec)
3592 event->attr.enable_on_exec = 0;
3593 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3596 __perf_event_mark_enabled(event);
3602 * Enable all of a task's events that have been marked enable-on-exec.
3603 * This expects task == current.
3605 static void perf_event_enable_on_exec(int ctxn)
3607 struct perf_event_context *ctx, *clone_ctx = NULL;
3608 enum event_type_t event_type = 0;
3609 struct perf_cpu_context *cpuctx;
3610 struct perf_event *event;
3611 unsigned long flags;
3614 local_irq_save(flags);
3615 ctx = current->perf_event_ctxp[ctxn];
3616 if (!ctx || !ctx->nr_events)
3619 cpuctx = __get_cpu_context(ctx);
3620 perf_ctx_lock(cpuctx, ctx);
3621 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3622 list_for_each_entry(event, &ctx->event_list, event_entry) {
3623 enabled |= event_enable_on_exec(event, ctx);
3624 event_type |= get_event_type(event);
3628 * Unclone and reschedule this context if we enabled any event.
3631 clone_ctx = unclone_ctx(ctx);
3632 ctx_resched(cpuctx, ctx, event_type);
3634 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3636 perf_ctx_unlock(cpuctx, ctx);
3639 local_irq_restore(flags);
3645 struct perf_read_data {
3646 struct perf_event *event;
3651 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3653 u16 local_pkg, event_pkg;
3655 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3656 int local_cpu = smp_processor_id();
3658 event_pkg = topology_physical_package_id(event_cpu);
3659 local_pkg = topology_physical_package_id(local_cpu);
3661 if (event_pkg == local_pkg)
3669 * Cross CPU call to read the hardware event
3671 static void __perf_event_read(void *info)
3673 struct perf_read_data *data = info;
3674 struct perf_event *sub, *event = data->event;
3675 struct perf_event_context *ctx = event->ctx;
3676 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3677 struct pmu *pmu = event->pmu;
3680 * If this is a task context, we need to check whether it is
3681 * the current task context of this cpu. If not it has been
3682 * scheduled out before the smp call arrived. In that case
3683 * event->count would have been updated to a recent sample
3684 * when the event was scheduled out.
3686 if (ctx->task && cpuctx->task_ctx != ctx)
3689 raw_spin_lock(&ctx->lock);
3690 if (ctx->is_active) {
3691 update_context_time(ctx);
3692 update_cgrp_time_from_event(event);
3695 update_event_times(event);
3696 if (event->state != PERF_EVENT_STATE_ACTIVE)
3705 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3709 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3710 update_event_times(sub);
3711 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3713 * Use sibling's PMU rather than @event's since
3714 * sibling could be on different (eg: software) PMU.
3716 sub->pmu->read(sub);
3720 data->ret = pmu->commit_txn(pmu);
3723 raw_spin_unlock(&ctx->lock);
3726 static inline u64 perf_event_count(struct perf_event *event)
3728 return local64_read(&event->count) + atomic64_read(&event->child_count);
3732 * NMI-safe method to read a local event, that is an event that
3734 * - either for the current task, or for this CPU
3735 * - does not have inherit set, for inherited task events
3736 * will not be local and we cannot read them atomically
3737 * - must not have a pmu::count method
3739 int perf_event_read_local(struct perf_event *event, u64 *value)
3741 unsigned long flags;
3745 * Disabling interrupts avoids all counter scheduling (context
3746 * switches, timer based rotation and IPIs).
3748 local_irq_save(flags);
3751 * It must not be an event with inherit set, we cannot read
3752 * all child counters from atomic context.
3754 if (event->attr.inherit) {
3759 /* If this is a per-task event, it must be for current */
3760 if ((event->attach_state & PERF_ATTACH_TASK) &&
3761 event->hw.target != current) {
3766 /* If this is a per-CPU event, it must be for this CPU */
3767 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3768 event->cpu != smp_processor_id()) {
3773 /* If this is a pinned event it must be running on this CPU */
3774 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3780 * If the event is currently on this CPU, its either a per-task event,
3781 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3784 if (event->oncpu == smp_processor_id())
3785 event->pmu->read(event);
3787 *value = local64_read(&event->count);
3789 local_irq_restore(flags);
3794 static int perf_event_read(struct perf_event *event, bool group)
3796 int event_cpu, ret = 0;
3799 * If event is enabled and currently active on a CPU, update the
3800 * value in the event structure:
3802 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3803 struct perf_read_data data = {
3809 event_cpu = READ_ONCE(event->oncpu);
3810 if ((unsigned)event_cpu >= nr_cpu_ids)
3814 event_cpu = __perf_event_read_cpu(event, event_cpu);
3817 * Purposely ignore the smp_call_function_single() return
3820 * If event_cpu isn't a valid CPU it means the event got
3821 * scheduled out and that will have updated the event count.
3823 * Therefore, either way, we'll have an up-to-date event count
3826 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3829 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3830 struct perf_event_context *ctx = event->ctx;
3831 unsigned long flags;
3833 raw_spin_lock_irqsave(&ctx->lock, flags);
3835 * may read while context is not active
3836 * (e.g., thread is blocked), in that case
3837 * we cannot update context time
3839 if (ctx->is_active) {
3840 update_context_time(ctx);
3841 update_cgrp_time_from_event(event);
3844 update_group_times(event);
3846 update_event_times(event);
3847 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3854 * Initialize the perf_event context in a task_struct:
3856 static void __perf_event_init_context(struct perf_event_context *ctx)
3858 raw_spin_lock_init(&ctx->lock);
3859 mutex_init(&ctx->mutex);
3860 INIT_LIST_HEAD(&ctx->active_ctx_list);
3861 INIT_LIST_HEAD(&ctx->pinned_groups);
3862 INIT_LIST_HEAD(&ctx->flexible_groups);
3863 INIT_LIST_HEAD(&ctx->event_list);
3864 atomic_set(&ctx->refcount, 1);
3867 static struct perf_event_context *
3868 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3870 struct perf_event_context *ctx;
3872 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3876 __perf_event_init_context(ctx);
3879 get_task_struct(task);
3886 static struct task_struct *
3887 find_lively_task_by_vpid(pid_t vpid)
3889 struct task_struct *task;
3895 task = find_task_by_vpid(vpid);
3897 get_task_struct(task);
3901 return ERR_PTR(-ESRCH);
3907 * Returns a matching context with refcount and pincount.
3909 static struct perf_event_context *
3910 find_get_context(struct pmu *pmu, struct task_struct *task,
3911 struct perf_event *event)
3913 struct perf_event_context *ctx, *clone_ctx = NULL;
3914 struct perf_cpu_context *cpuctx;
3915 void *task_ctx_data = NULL;
3916 unsigned long flags;
3918 int cpu = event->cpu;
3921 /* Must be root to operate on a CPU event: */
3922 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3923 return ERR_PTR(-EACCES);
3925 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3928 raw_spin_lock_irqsave(&ctx->lock, flags);
3930 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3936 ctxn = pmu->task_ctx_nr;
3940 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3941 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3942 if (!task_ctx_data) {
3949 ctx = perf_lock_task_context(task, ctxn, &flags);
3951 clone_ctx = unclone_ctx(ctx);
3954 if (task_ctx_data && !ctx->task_ctx_data) {
3955 ctx->task_ctx_data = task_ctx_data;
3956 task_ctx_data = NULL;
3958 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3963 ctx = alloc_perf_context(pmu, task);
3968 if (task_ctx_data) {
3969 ctx->task_ctx_data = task_ctx_data;
3970 task_ctx_data = NULL;
3974 mutex_lock(&task->perf_event_mutex);
3976 * If it has already passed perf_event_exit_task().
3977 * we must see PF_EXITING, it takes this mutex too.
3979 if (task->flags & PF_EXITING)
3981 else if (task->perf_event_ctxp[ctxn])
3986 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3988 mutex_unlock(&task->perf_event_mutex);
3990 if (unlikely(err)) {
3999 kfree(task_ctx_data);
4003 kfree(task_ctx_data);
4004 return ERR_PTR(err);
4007 static void perf_event_free_filter(struct perf_event *event);
4008 static void perf_event_free_bpf_prog(struct perf_event *event);
4010 static void free_event_rcu(struct rcu_head *head)
4012 struct perf_event *event;
4014 event = container_of(head, struct perf_event, rcu_head);
4016 put_pid_ns(event->ns);
4017 perf_event_free_filter(event);
4021 static void ring_buffer_attach(struct perf_event *event,
4022 struct ring_buffer *rb);
4024 static void detach_sb_event(struct perf_event *event)
4026 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4028 raw_spin_lock(&pel->lock);
4029 list_del_rcu(&event->sb_list);
4030 raw_spin_unlock(&pel->lock);
4033 static bool is_sb_event(struct perf_event *event)
4035 struct perf_event_attr *attr = &event->attr;
4040 if (event->attach_state & PERF_ATTACH_TASK)
4043 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4044 attr->comm || attr->comm_exec ||
4046 attr->context_switch)
4051 static void unaccount_pmu_sb_event(struct perf_event *event)
4053 if (is_sb_event(event))
4054 detach_sb_event(event);
4057 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4062 if (is_cgroup_event(event))
4063 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4066 #ifdef CONFIG_NO_HZ_FULL
4067 static DEFINE_SPINLOCK(nr_freq_lock);
4070 static void unaccount_freq_event_nohz(void)
4072 #ifdef CONFIG_NO_HZ_FULL
4073 spin_lock(&nr_freq_lock);
4074 if (atomic_dec_and_test(&nr_freq_events))
4075 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4076 spin_unlock(&nr_freq_lock);
4080 static void unaccount_freq_event(void)
4082 if (tick_nohz_full_enabled())
4083 unaccount_freq_event_nohz();
4085 atomic_dec(&nr_freq_events);
4088 static void unaccount_event(struct perf_event *event)
4095 if (event->attach_state & PERF_ATTACH_TASK)
4097 if (event->attr.mmap || event->attr.mmap_data)
4098 atomic_dec(&nr_mmap_events);
4099 if (event->attr.comm)
4100 atomic_dec(&nr_comm_events);
4101 if (event->attr.namespaces)
4102 atomic_dec(&nr_namespaces_events);
4103 if (event->attr.task)
4104 atomic_dec(&nr_task_events);
4105 if (event->attr.freq)
4106 unaccount_freq_event();
4107 if (event->attr.context_switch) {
4109 atomic_dec(&nr_switch_events);
4111 if (is_cgroup_event(event))
4113 if (has_branch_stack(event))
4117 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4118 schedule_delayed_work(&perf_sched_work, HZ);
4121 unaccount_event_cpu(event, event->cpu);
4123 unaccount_pmu_sb_event(event);
4126 static void perf_sched_delayed(struct work_struct *work)
4128 mutex_lock(&perf_sched_mutex);
4129 if (atomic_dec_and_test(&perf_sched_count))
4130 static_branch_disable(&perf_sched_events);
4131 mutex_unlock(&perf_sched_mutex);
4135 * The following implement mutual exclusion of events on "exclusive" pmus
4136 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4137 * at a time, so we disallow creating events that might conflict, namely:
4139 * 1) cpu-wide events in the presence of per-task events,
4140 * 2) per-task events in the presence of cpu-wide events,
4141 * 3) two matching events on the same context.
4143 * The former two cases are handled in the allocation path (perf_event_alloc(),
4144 * _free_event()), the latter -- before the first perf_install_in_context().
4146 static int exclusive_event_init(struct perf_event *event)
4148 struct pmu *pmu = event->pmu;
4150 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4154 * Prevent co-existence of per-task and cpu-wide events on the
4155 * same exclusive pmu.
4157 * Negative pmu::exclusive_cnt means there are cpu-wide
4158 * events on this "exclusive" pmu, positive means there are
4161 * Since this is called in perf_event_alloc() path, event::ctx
4162 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4163 * to mean "per-task event", because unlike other attach states it
4164 * never gets cleared.
4166 if (event->attach_state & PERF_ATTACH_TASK) {
4167 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4170 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4177 static void exclusive_event_destroy(struct perf_event *event)
4179 struct pmu *pmu = event->pmu;
4181 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4184 /* see comment in exclusive_event_init() */
4185 if (event->attach_state & PERF_ATTACH_TASK)
4186 atomic_dec(&pmu->exclusive_cnt);
4188 atomic_inc(&pmu->exclusive_cnt);
4191 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4193 if ((e1->pmu == e2->pmu) &&
4194 (e1->cpu == e2->cpu ||
4201 /* Called under the same ctx::mutex as perf_install_in_context() */
4202 static bool exclusive_event_installable(struct perf_event *event,
4203 struct perf_event_context *ctx)
4205 struct perf_event *iter_event;
4206 struct pmu *pmu = event->pmu;
4208 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4211 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4212 if (exclusive_event_match(iter_event, event))
4219 static void perf_addr_filters_splice(struct perf_event *event,
4220 struct list_head *head);
4222 static void _free_event(struct perf_event *event)
4224 irq_work_sync(&event->pending);
4226 unaccount_event(event);
4230 * Can happen when we close an event with re-directed output.
4232 * Since we have a 0 refcount, perf_mmap_close() will skip
4233 * over us; possibly making our ring_buffer_put() the last.
4235 mutex_lock(&event->mmap_mutex);
4236 ring_buffer_attach(event, NULL);
4237 mutex_unlock(&event->mmap_mutex);
4240 if (is_cgroup_event(event))
4241 perf_detach_cgroup(event);
4243 if (!event->parent) {
4244 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4245 put_callchain_buffers();
4248 perf_event_free_bpf_prog(event);
4249 perf_addr_filters_splice(event, NULL);
4250 kfree(event->addr_filters_offs);
4253 event->destroy(event);
4256 put_ctx(event->ctx);
4258 if (event->hw.target)
4259 put_task_struct(event->hw.target);
4261 exclusive_event_destroy(event);
4262 module_put(event->pmu->module);
4264 call_rcu(&event->rcu_head, free_event_rcu);
4268 * Used to free events which have a known refcount of 1, such as in error paths
4269 * where the event isn't exposed yet and inherited events.
4271 static void free_event(struct perf_event *event)
4273 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4274 "unexpected event refcount: %ld; ptr=%p\n",
4275 atomic_long_read(&event->refcount), event)) {
4276 /* leak to avoid use-after-free */
4284 * Remove user event from the owner task.
4286 static void perf_remove_from_owner(struct perf_event *event)
4288 struct task_struct *owner;
4292 * Matches the smp_store_release() in perf_event_exit_task(). If we
4293 * observe !owner it means the list deletion is complete and we can
4294 * indeed free this event, otherwise we need to serialize on
4295 * owner->perf_event_mutex.
4297 owner = READ_ONCE(event->owner);
4300 * Since delayed_put_task_struct() also drops the last
4301 * task reference we can safely take a new reference
4302 * while holding the rcu_read_lock().
4304 get_task_struct(owner);
4310 * If we're here through perf_event_exit_task() we're already
4311 * holding ctx->mutex which would be an inversion wrt. the
4312 * normal lock order.
4314 * However we can safely take this lock because its the child
4317 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4320 * We have to re-check the event->owner field, if it is cleared
4321 * we raced with perf_event_exit_task(), acquiring the mutex
4322 * ensured they're done, and we can proceed with freeing the
4326 list_del_init(&event->owner_entry);
4327 smp_store_release(&event->owner, NULL);
4329 mutex_unlock(&owner->perf_event_mutex);
4330 put_task_struct(owner);
4334 static void put_event(struct perf_event *event)
4336 if (!atomic_long_dec_and_test(&event->refcount))
4343 * Kill an event dead; while event:refcount will preserve the event
4344 * object, it will not preserve its functionality. Once the last 'user'
4345 * gives up the object, we'll destroy the thing.
4347 int perf_event_release_kernel(struct perf_event *event)
4349 struct perf_event_context *ctx = event->ctx;
4350 struct perf_event *child, *tmp;
4353 * If we got here through err_file: fput(event_file); we will not have
4354 * attached to a context yet.
4357 WARN_ON_ONCE(event->attach_state &
4358 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4362 if (!is_kernel_event(event))
4363 perf_remove_from_owner(event);
4365 ctx = perf_event_ctx_lock(event);
4366 WARN_ON_ONCE(ctx->parent_ctx);
4367 perf_remove_from_context(event, DETACH_GROUP);
4369 raw_spin_lock_irq(&ctx->lock);
4371 * Mark this event as STATE_DEAD, there is no external reference to it
4374 * Anybody acquiring event->child_mutex after the below loop _must_
4375 * also see this, most importantly inherit_event() which will avoid
4376 * placing more children on the list.
4378 * Thus this guarantees that we will in fact observe and kill _ALL_
4381 event->state = PERF_EVENT_STATE_DEAD;
4382 raw_spin_unlock_irq(&ctx->lock);
4384 perf_event_ctx_unlock(event, ctx);
4387 mutex_lock(&event->child_mutex);
4388 list_for_each_entry(child, &event->child_list, child_list) {
4391 * Cannot change, child events are not migrated, see the
4392 * comment with perf_event_ctx_lock_nested().
4394 ctx = READ_ONCE(child->ctx);
4396 * Since child_mutex nests inside ctx::mutex, we must jump
4397 * through hoops. We start by grabbing a reference on the ctx.
4399 * Since the event cannot get freed while we hold the
4400 * child_mutex, the context must also exist and have a !0
4406 * Now that we have a ctx ref, we can drop child_mutex, and
4407 * acquire ctx::mutex without fear of it going away. Then we
4408 * can re-acquire child_mutex.
4410 mutex_unlock(&event->child_mutex);
4411 mutex_lock(&ctx->mutex);
4412 mutex_lock(&event->child_mutex);
4415 * Now that we hold ctx::mutex and child_mutex, revalidate our
4416 * state, if child is still the first entry, it didn't get freed
4417 * and we can continue doing so.
4419 tmp = list_first_entry_or_null(&event->child_list,
4420 struct perf_event, child_list);
4422 perf_remove_from_context(child, DETACH_GROUP);
4423 list_del(&child->child_list);
4426 * This matches the refcount bump in inherit_event();
4427 * this can't be the last reference.
4432 mutex_unlock(&event->child_mutex);
4433 mutex_unlock(&ctx->mutex);
4437 mutex_unlock(&event->child_mutex);
4440 put_event(event); /* Must be the 'last' reference */
4443 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4446 * Called when the last reference to the file is gone.
4448 static int perf_release(struct inode *inode, struct file *file)
4450 perf_event_release_kernel(file->private_data);
4454 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4456 struct perf_event *child;
4462 mutex_lock(&event->child_mutex);
4464 (void)perf_event_read(event, false);
4465 total += perf_event_count(event);
4467 *enabled += event->total_time_enabled +
4468 atomic64_read(&event->child_total_time_enabled);
4469 *running += event->total_time_running +
4470 atomic64_read(&event->child_total_time_running);
4472 list_for_each_entry(child, &event->child_list, child_list) {
4473 (void)perf_event_read(child, false);
4474 total += perf_event_count(child);
4475 *enabled += child->total_time_enabled;
4476 *running += child->total_time_running;
4478 mutex_unlock(&event->child_mutex);
4482 EXPORT_SYMBOL_GPL(perf_event_read_value);
4484 static int __perf_read_group_add(struct perf_event *leader,
4485 u64 read_format, u64 *values)
4487 struct perf_event_context *ctx = leader->ctx;
4488 struct perf_event *sub, *parent;
4489 unsigned long flags;
4490 int n = 1; /* skip @nr */
4493 ret = perf_event_read(leader, true);
4497 raw_spin_lock_irqsave(&ctx->lock, flags);
4499 * Verify the grouping between the parent and child (inherited)
4500 * events is still in tact.
4503 * - leader->ctx->lock pins leader->sibling_list
4504 * - parent->child_mutex pins parent->child_list
4505 * - parent->ctx->mutex pins parent->sibling_list
4507 * Because parent->ctx != leader->ctx (and child_list nests inside
4508 * ctx->mutex), group destruction is not atomic between children, also
4509 * see perf_event_release_kernel(). Additionally, parent can grow the
4512 * Therefore it is possible to have parent and child groups in a
4513 * different configuration and summing over such a beast makes no sense
4518 parent = leader->parent;
4520 (parent->group_generation != leader->group_generation ||
4521 parent->nr_siblings != leader->nr_siblings)) {
4527 * Since we co-schedule groups, {enabled,running} times of siblings
4528 * will be identical to those of the leader, so we only publish one
4531 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4532 values[n++] += leader->total_time_enabled +
4533 atomic64_read(&leader->child_total_time_enabled);
4536 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4537 values[n++] += leader->total_time_running +
4538 atomic64_read(&leader->child_total_time_running);
4542 * Write {count,id} tuples for every sibling.
4544 values[n++] += perf_event_count(leader);
4545 if (read_format & PERF_FORMAT_ID)
4546 values[n++] = primary_event_id(leader);
4548 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4549 values[n++] += perf_event_count(sub);
4550 if (read_format & PERF_FORMAT_ID)
4551 values[n++] = primary_event_id(sub);
4555 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4559 static int perf_read_group(struct perf_event *event,
4560 u64 read_format, char __user *buf)
4562 struct perf_event *leader = event->group_leader, *child;
4563 struct perf_event_context *ctx = leader->ctx;
4567 lockdep_assert_held(&ctx->mutex);
4569 values = kzalloc(event->read_size, GFP_KERNEL);
4573 values[0] = 1 + leader->nr_siblings;
4575 mutex_lock(&leader->child_mutex);
4577 ret = __perf_read_group_add(leader, read_format, values);
4581 list_for_each_entry(child, &leader->child_list, child_list) {
4582 ret = __perf_read_group_add(child, read_format, values);
4587 mutex_unlock(&leader->child_mutex);
4589 ret = event->read_size;
4590 if (copy_to_user(buf, values, event->read_size))
4595 mutex_unlock(&leader->child_mutex);
4601 static int perf_read_one(struct perf_event *event,
4602 u64 read_format, char __user *buf)
4604 u64 enabled, running;
4608 values[n++] = perf_event_read_value(event, &enabled, &running);
4609 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4610 values[n++] = enabled;
4611 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4612 values[n++] = running;
4613 if (read_format & PERF_FORMAT_ID)
4614 values[n++] = primary_event_id(event);
4616 if (copy_to_user(buf, values, n * sizeof(u64)))
4619 return n * sizeof(u64);
4622 static bool is_event_hup(struct perf_event *event)
4626 if (event->state > PERF_EVENT_STATE_EXIT)
4629 mutex_lock(&event->child_mutex);
4630 no_children = list_empty(&event->child_list);
4631 mutex_unlock(&event->child_mutex);
4636 * Read the performance event - simple non blocking version for now
4639 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4641 u64 read_format = event->attr.read_format;
4645 * Return end-of-file for a read on a event that is in
4646 * error state (i.e. because it was pinned but it couldn't be
4647 * scheduled on to the CPU at some point).
4649 if (event->state == PERF_EVENT_STATE_ERROR)
4652 if (count < event->read_size)
4655 WARN_ON_ONCE(event->ctx->parent_ctx);
4656 if (read_format & PERF_FORMAT_GROUP)
4657 ret = perf_read_group(event, read_format, buf);
4659 ret = perf_read_one(event, read_format, buf);
4665 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4667 struct perf_event *event = file->private_data;
4668 struct perf_event_context *ctx;
4671 ctx = perf_event_ctx_lock(event);
4672 ret = __perf_read(event, buf, count);
4673 perf_event_ctx_unlock(event, ctx);
4678 static unsigned int perf_poll(struct file *file, poll_table *wait)
4680 struct perf_event *event = file->private_data;
4681 struct ring_buffer *rb;
4682 unsigned int events = POLLHUP;
4684 poll_wait(file, &event->waitq, wait);
4686 if (is_event_hup(event))
4690 * Pin the event->rb by taking event->mmap_mutex; otherwise
4691 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4693 mutex_lock(&event->mmap_mutex);
4696 events = atomic_xchg(&rb->poll, 0);
4697 mutex_unlock(&event->mmap_mutex);
4701 static void _perf_event_reset(struct perf_event *event)
4703 (void)perf_event_read(event, false);
4704 local64_set(&event->count, 0);
4705 perf_event_update_userpage(event);
4709 * Holding the top-level event's child_mutex means that any
4710 * descendant process that has inherited this event will block
4711 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4712 * task existence requirements of perf_event_enable/disable.
4714 static void perf_event_for_each_child(struct perf_event *event,
4715 void (*func)(struct perf_event *))
4717 struct perf_event *child;
4719 WARN_ON_ONCE(event->ctx->parent_ctx);
4721 mutex_lock(&event->child_mutex);
4723 list_for_each_entry(child, &event->child_list, child_list)
4725 mutex_unlock(&event->child_mutex);
4728 static void perf_event_for_each(struct perf_event *event,
4729 void (*func)(struct perf_event *))
4731 struct perf_event_context *ctx = event->ctx;
4732 struct perf_event *sibling;
4734 lockdep_assert_held(&ctx->mutex);
4736 event = event->group_leader;
4738 perf_event_for_each_child(event, func);
4739 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4740 perf_event_for_each_child(sibling, func);
4743 static void __perf_event_period(struct perf_event *event,
4744 struct perf_cpu_context *cpuctx,
4745 struct perf_event_context *ctx,
4748 u64 value = *((u64 *)info);
4751 if (event->attr.freq) {
4752 event->attr.sample_freq = value;
4754 event->attr.sample_period = value;
4755 event->hw.sample_period = value;
4758 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4760 perf_pmu_disable(ctx->pmu);
4762 * We could be throttled; unthrottle now to avoid the tick
4763 * trying to unthrottle while we already re-started the event.
4765 if (event->hw.interrupts == MAX_INTERRUPTS) {
4766 event->hw.interrupts = 0;
4767 perf_log_throttle(event, 1);
4769 event->pmu->stop(event, PERF_EF_UPDATE);
4772 local64_set(&event->hw.period_left, 0);
4775 event->pmu->start(event, PERF_EF_RELOAD);
4776 perf_pmu_enable(ctx->pmu);
4780 static int perf_event_check_period(struct perf_event *event, u64 value)
4782 return event->pmu->check_period(event, value);
4785 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4789 if (!is_sampling_event(event))
4792 if (copy_from_user(&value, arg, sizeof(value)))
4798 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4801 if (perf_event_check_period(event, value))
4804 if (!event->attr.freq && (value & (1ULL << 63)))
4807 event_function_call(event, __perf_event_period, &value);
4812 static const struct file_operations perf_fops;
4814 static inline int perf_fget_light(int fd, struct fd *p)
4816 struct fd f = fdget(fd);
4820 if (f.file->f_op != &perf_fops) {
4828 static int perf_event_set_output(struct perf_event *event,
4829 struct perf_event *output_event);
4830 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4831 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4833 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4835 void (*func)(struct perf_event *);
4839 case PERF_EVENT_IOC_ENABLE:
4840 func = _perf_event_enable;
4842 case PERF_EVENT_IOC_DISABLE:
4843 func = _perf_event_disable;
4845 case PERF_EVENT_IOC_RESET:
4846 func = _perf_event_reset;
4849 case PERF_EVENT_IOC_REFRESH:
4850 return _perf_event_refresh(event, arg);
4852 case PERF_EVENT_IOC_PERIOD:
4853 return perf_event_period(event, (u64 __user *)arg);
4855 case PERF_EVENT_IOC_ID:
4857 u64 id = primary_event_id(event);
4859 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4864 case PERF_EVENT_IOC_SET_OUTPUT:
4868 struct perf_event *output_event;
4870 ret = perf_fget_light(arg, &output);
4873 output_event = output.file->private_data;
4874 ret = perf_event_set_output(event, output_event);
4877 ret = perf_event_set_output(event, NULL);
4882 case PERF_EVENT_IOC_SET_FILTER:
4883 return perf_event_set_filter(event, (void __user *)arg);
4885 case PERF_EVENT_IOC_SET_BPF:
4886 return perf_event_set_bpf_prog(event, arg);
4888 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4889 struct ring_buffer *rb;
4892 rb = rcu_dereference(event->rb);
4893 if (!rb || !rb->nr_pages) {
4897 rb_toggle_paused(rb, !!arg);
4905 if (flags & PERF_IOC_FLAG_GROUP)
4906 perf_event_for_each(event, func);
4908 perf_event_for_each_child(event, func);
4913 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4915 struct perf_event *event = file->private_data;
4916 struct perf_event_context *ctx;
4919 ctx = perf_event_ctx_lock(event);
4920 ret = _perf_ioctl(event, cmd, arg);
4921 perf_event_ctx_unlock(event, ctx);
4926 #ifdef CONFIG_COMPAT
4927 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4930 switch (_IOC_NR(cmd)) {
4931 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4932 case _IOC_NR(PERF_EVENT_IOC_ID):
4933 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4934 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4935 cmd &= ~IOCSIZE_MASK;
4936 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4940 return perf_ioctl(file, cmd, arg);
4943 # define perf_compat_ioctl NULL
4946 int perf_event_task_enable(void)
4948 struct perf_event_context *ctx;
4949 struct perf_event *event;
4951 mutex_lock(¤t->perf_event_mutex);
4952 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4953 ctx = perf_event_ctx_lock(event);
4954 perf_event_for_each_child(event, _perf_event_enable);
4955 perf_event_ctx_unlock(event, ctx);
4957 mutex_unlock(¤t->perf_event_mutex);
4962 int perf_event_task_disable(void)
4964 struct perf_event_context *ctx;
4965 struct perf_event *event;
4967 mutex_lock(¤t->perf_event_mutex);
4968 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4969 ctx = perf_event_ctx_lock(event);
4970 perf_event_for_each_child(event, _perf_event_disable);
4971 perf_event_ctx_unlock(event, ctx);
4973 mutex_unlock(¤t->perf_event_mutex);
4978 static int perf_event_index(struct perf_event *event)
4980 if (event->hw.state & PERF_HES_STOPPED)
4983 if (event->state != PERF_EVENT_STATE_ACTIVE)
4986 return event->pmu->event_idx(event);
4989 static void calc_timer_values(struct perf_event *event,
4996 *now = perf_clock();
4997 ctx_time = event->shadow_ctx_time + *now;
4998 *enabled = ctx_time - event->tstamp_enabled;
4999 *running = ctx_time - event->tstamp_running;
5002 static void perf_event_init_userpage(struct perf_event *event)
5004 struct perf_event_mmap_page *userpg;
5005 struct ring_buffer *rb;
5008 rb = rcu_dereference(event->rb);
5012 userpg = rb->user_page;
5014 /* Allow new userspace to detect that bit 0 is deprecated */
5015 userpg->cap_bit0_is_deprecated = 1;
5016 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5017 userpg->data_offset = PAGE_SIZE;
5018 userpg->data_size = perf_data_size(rb);
5024 void __weak arch_perf_update_userpage(
5025 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5030 * Callers need to ensure there can be no nesting of this function, otherwise
5031 * the seqlock logic goes bad. We can not serialize this because the arch
5032 * code calls this from NMI context.
5034 void perf_event_update_userpage(struct perf_event *event)
5036 struct perf_event_mmap_page *userpg;
5037 struct ring_buffer *rb;
5038 u64 enabled, running, now;
5041 rb = rcu_dereference(event->rb);
5046 * compute total_time_enabled, total_time_running
5047 * based on snapshot values taken when the event
5048 * was last scheduled in.
5050 * we cannot simply called update_context_time()
5051 * because of locking issue as we can be called in
5054 calc_timer_values(event, &now, &enabled, &running);
5056 userpg = rb->user_page;
5058 * Disable preemption so as to not let the corresponding user-space
5059 * spin too long if we get preempted.
5064 userpg->index = perf_event_index(event);
5065 userpg->offset = perf_event_count(event);
5067 userpg->offset -= local64_read(&event->hw.prev_count);
5069 userpg->time_enabled = enabled +
5070 atomic64_read(&event->child_total_time_enabled);
5072 userpg->time_running = running +
5073 atomic64_read(&event->child_total_time_running);
5075 arch_perf_update_userpage(event, userpg, now);
5084 static int perf_mmap_fault(struct vm_fault *vmf)
5086 struct perf_event *event = vmf->vma->vm_file->private_data;
5087 struct ring_buffer *rb;
5088 int ret = VM_FAULT_SIGBUS;
5090 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5091 if (vmf->pgoff == 0)
5097 rb = rcu_dereference(event->rb);
5101 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5104 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5108 get_page(vmf->page);
5109 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5110 vmf->page->index = vmf->pgoff;
5119 static void ring_buffer_attach(struct perf_event *event,
5120 struct ring_buffer *rb)
5122 struct ring_buffer *old_rb = NULL;
5123 unsigned long flags;
5127 * Should be impossible, we set this when removing
5128 * event->rb_entry and wait/clear when adding event->rb_entry.
5130 WARN_ON_ONCE(event->rcu_pending);
5133 spin_lock_irqsave(&old_rb->event_lock, flags);
5134 list_del_rcu(&event->rb_entry);
5135 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5137 event->rcu_batches = get_state_synchronize_rcu();
5138 event->rcu_pending = 1;
5142 if (event->rcu_pending) {
5143 cond_synchronize_rcu(event->rcu_batches);
5144 event->rcu_pending = 0;
5147 spin_lock_irqsave(&rb->event_lock, flags);
5148 list_add_rcu(&event->rb_entry, &rb->event_list);
5149 spin_unlock_irqrestore(&rb->event_lock, flags);
5153 * Avoid racing with perf_mmap_close(AUX): stop the event
5154 * before swizzling the event::rb pointer; if it's getting
5155 * unmapped, its aux_mmap_count will be 0 and it won't
5156 * restart. See the comment in __perf_pmu_output_stop().
5158 * Data will inevitably be lost when set_output is done in
5159 * mid-air, but then again, whoever does it like this is
5160 * not in for the data anyway.
5163 perf_event_stop(event, 0);
5165 rcu_assign_pointer(event->rb, rb);
5168 ring_buffer_put(old_rb);
5170 * Since we detached before setting the new rb, so that we
5171 * could attach the new rb, we could have missed a wakeup.
5174 wake_up_all(&event->waitq);
5178 static void ring_buffer_wakeup(struct perf_event *event)
5180 struct ring_buffer *rb;
5183 rb = rcu_dereference(event->rb);
5185 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5186 wake_up_all(&event->waitq);
5191 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5193 struct ring_buffer *rb;
5196 rb = rcu_dereference(event->rb);
5198 if (!atomic_inc_not_zero(&rb->refcount))
5206 void ring_buffer_put(struct ring_buffer *rb)
5208 if (!atomic_dec_and_test(&rb->refcount))
5211 WARN_ON_ONCE(!list_empty(&rb->event_list));
5213 call_rcu(&rb->rcu_head, rb_free_rcu);
5216 static void perf_mmap_open(struct vm_area_struct *vma)
5218 struct perf_event *event = vma->vm_file->private_data;
5220 atomic_inc(&event->mmap_count);
5221 atomic_inc(&event->rb->mmap_count);
5224 atomic_inc(&event->rb->aux_mmap_count);
5226 if (event->pmu->event_mapped)
5227 event->pmu->event_mapped(event, vma->vm_mm);
5230 static void perf_pmu_output_stop(struct perf_event *event);
5233 * A buffer can be mmap()ed multiple times; either directly through the same
5234 * event, or through other events by use of perf_event_set_output().
5236 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5237 * the buffer here, where we still have a VM context. This means we need
5238 * to detach all events redirecting to us.
5240 static void perf_mmap_close(struct vm_area_struct *vma)
5242 struct perf_event *event = vma->vm_file->private_data;
5243 struct ring_buffer *rb = ring_buffer_get(event);
5244 struct user_struct *mmap_user = rb->mmap_user;
5245 int mmap_locked = rb->mmap_locked;
5246 unsigned long size = perf_data_size(rb);
5247 bool detach_rest = false;
5249 if (event->pmu->event_unmapped)
5250 event->pmu->event_unmapped(event, vma->vm_mm);
5253 * rb->aux_mmap_count will always drop before rb->mmap_count and
5254 * event->mmap_count, so it is ok to use event->mmap_mutex to
5255 * serialize with perf_mmap here.
5257 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5258 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5260 * Stop all AUX events that are writing to this buffer,
5261 * so that we can free its AUX pages and corresponding PMU
5262 * data. Note that after rb::aux_mmap_count dropped to zero,
5263 * they won't start any more (see perf_aux_output_begin()).
5265 perf_pmu_output_stop(event);
5267 /* now it's safe to free the pages */
5268 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5269 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5271 /* this has to be the last one */
5273 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5275 mutex_unlock(&event->mmap_mutex);
5278 if (atomic_dec_and_test(&rb->mmap_count))
5281 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5284 ring_buffer_attach(event, NULL);
5285 mutex_unlock(&event->mmap_mutex);
5287 /* If there's still other mmap()s of this buffer, we're done. */
5292 * No other mmap()s, detach from all other events that might redirect
5293 * into the now unreachable buffer. Somewhat complicated by the
5294 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5298 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5299 if (!atomic_long_inc_not_zero(&event->refcount)) {
5301 * This event is en-route to free_event() which will
5302 * detach it and remove it from the list.
5308 mutex_lock(&event->mmap_mutex);
5310 * Check we didn't race with perf_event_set_output() which can
5311 * swizzle the rb from under us while we were waiting to
5312 * acquire mmap_mutex.
5314 * If we find a different rb; ignore this event, a next
5315 * iteration will no longer find it on the list. We have to
5316 * still restart the iteration to make sure we're not now
5317 * iterating the wrong list.
5319 if (event->rb == rb)
5320 ring_buffer_attach(event, NULL);
5322 mutex_unlock(&event->mmap_mutex);
5326 * Restart the iteration; either we're on the wrong list or
5327 * destroyed its integrity by doing a deletion.
5334 * It could be there's still a few 0-ref events on the list; they'll
5335 * get cleaned up by free_event() -- they'll also still have their
5336 * ref on the rb and will free it whenever they are done with it.
5338 * Aside from that, this buffer is 'fully' detached and unmapped,
5339 * undo the VM accounting.
5342 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5343 vma->vm_mm->pinned_vm -= mmap_locked;
5344 free_uid(mmap_user);
5347 ring_buffer_put(rb); /* could be last */
5350 static const struct vm_operations_struct perf_mmap_vmops = {
5351 .open = perf_mmap_open,
5352 .close = perf_mmap_close, /* non mergable */
5353 .fault = perf_mmap_fault,
5354 .page_mkwrite = perf_mmap_fault,
5357 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5359 struct perf_event *event = file->private_data;
5360 unsigned long user_locked, user_lock_limit;
5361 struct user_struct *user = current_user();
5362 unsigned long locked, lock_limit;
5363 struct ring_buffer *rb = NULL;
5364 unsigned long vma_size;
5365 unsigned long nr_pages;
5366 long user_extra = 0, extra = 0;
5367 int ret = 0, flags = 0;
5370 * Don't allow mmap() of inherited per-task counters. This would
5371 * create a performance issue due to all children writing to the
5374 if (event->cpu == -1 && event->attr.inherit)
5377 if (!(vma->vm_flags & VM_SHARED))
5380 vma_size = vma->vm_end - vma->vm_start;
5382 if (vma->vm_pgoff == 0) {
5383 nr_pages = (vma_size / PAGE_SIZE) - 1;
5386 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5387 * mapped, all subsequent mappings should have the same size
5388 * and offset. Must be above the normal perf buffer.
5390 u64 aux_offset, aux_size;
5395 nr_pages = vma_size / PAGE_SIZE;
5397 mutex_lock(&event->mmap_mutex);
5404 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5405 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5407 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5410 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5413 /* already mapped with a different offset */
5414 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5417 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5420 /* already mapped with a different size */
5421 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5424 if (!is_power_of_2(nr_pages))
5427 if (!atomic_inc_not_zero(&rb->mmap_count))
5430 if (rb_has_aux(rb)) {
5431 atomic_inc(&rb->aux_mmap_count);
5436 atomic_set(&rb->aux_mmap_count, 1);
5437 user_extra = nr_pages;
5443 * If we have rb pages ensure they're a power-of-two number, so we
5444 * can do bitmasks instead of modulo.
5446 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5449 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5452 WARN_ON_ONCE(event->ctx->parent_ctx);
5454 mutex_lock(&event->mmap_mutex);
5456 if (event->rb->nr_pages != nr_pages) {
5461 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5463 * Raced against perf_mmap_close(); remove the
5464 * event and try again.
5466 ring_buffer_attach(event, NULL);
5467 mutex_unlock(&event->mmap_mutex);
5474 user_extra = nr_pages + 1;
5477 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5480 * Increase the limit linearly with more CPUs:
5482 user_lock_limit *= num_online_cpus();
5484 user_locked = atomic_long_read(&user->locked_vm);
5487 * sysctl_perf_event_mlock may have changed, so that
5488 * user->locked_vm > user_lock_limit
5490 if (user_locked > user_lock_limit)
5491 user_locked = user_lock_limit;
5492 user_locked += user_extra;
5494 if (user_locked > user_lock_limit)
5495 extra = user_locked - user_lock_limit;
5497 lock_limit = rlimit(RLIMIT_MEMLOCK);
5498 lock_limit >>= PAGE_SHIFT;
5499 locked = vma->vm_mm->pinned_vm + extra;
5501 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5502 !capable(CAP_IPC_LOCK)) {
5507 WARN_ON(!rb && event->rb);
5509 if (vma->vm_flags & VM_WRITE)
5510 flags |= RING_BUFFER_WRITABLE;
5513 rb = rb_alloc(nr_pages,
5514 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5522 atomic_set(&rb->mmap_count, 1);
5523 rb->mmap_user = get_current_user();
5524 rb->mmap_locked = extra;
5526 ring_buffer_attach(event, rb);
5528 perf_event_init_userpage(event);
5529 perf_event_update_userpage(event);
5531 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5532 event->attr.aux_watermark, flags);
5534 rb->aux_mmap_locked = extra;
5539 atomic_long_add(user_extra, &user->locked_vm);
5540 vma->vm_mm->pinned_vm += extra;
5542 atomic_inc(&event->mmap_count);
5544 atomic_dec(&rb->mmap_count);
5547 mutex_unlock(&event->mmap_mutex);
5550 * Since pinned accounting is per vm we cannot allow fork() to copy our
5553 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5554 vma->vm_ops = &perf_mmap_vmops;
5556 if (event->pmu->event_mapped)
5557 event->pmu->event_mapped(event, vma->vm_mm);
5562 static int perf_fasync(int fd, struct file *filp, int on)
5564 struct inode *inode = file_inode(filp);
5565 struct perf_event *event = filp->private_data;
5569 retval = fasync_helper(fd, filp, on, &event->fasync);
5570 inode_unlock(inode);
5578 static const struct file_operations perf_fops = {
5579 .llseek = no_llseek,
5580 .release = perf_release,
5583 .unlocked_ioctl = perf_ioctl,
5584 .compat_ioctl = perf_compat_ioctl,
5586 .fasync = perf_fasync,
5592 * If there's data, ensure we set the poll() state and publish everything
5593 * to user-space before waking everybody up.
5596 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5598 /* only the parent has fasync state */
5600 event = event->parent;
5601 return &event->fasync;
5604 void perf_event_wakeup(struct perf_event *event)
5606 ring_buffer_wakeup(event);
5608 if (event->pending_kill) {
5609 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5610 event->pending_kill = 0;
5614 static void perf_pending_event(struct irq_work *entry)
5616 struct perf_event *event = container_of(entry,
5617 struct perf_event, pending);
5620 rctx = perf_swevent_get_recursion_context();
5622 * If we 'fail' here, that's OK, it means recursion is already disabled
5623 * and we won't recurse 'further'.
5626 if (event->pending_disable) {
5627 event->pending_disable = 0;
5628 perf_event_disable_local(event);
5631 if (event->pending_wakeup) {
5632 event->pending_wakeup = 0;
5633 perf_event_wakeup(event);
5637 perf_swevent_put_recursion_context(rctx);
5641 * We assume there is only KVM supporting the callbacks.
5642 * Later on, we might change it to a list if there is
5643 * another virtualization implementation supporting the callbacks.
5645 struct perf_guest_info_callbacks *perf_guest_cbs;
5647 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5649 perf_guest_cbs = cbs;
5652 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5654 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5656 perf_guest_cbs = NULL;
5659 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5662 perf_output_sample_regs(struct perf_output_handle *handle,
5663 struct pt_regs *regs, u64 mask)
5666 DECLARE_BITMAP(_mask, 64);
5668 bitmap_from_u64(_mask, mask);
5669 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5672 val = perf_reg_value(regs, bit);
5673 perf_output_put(handle, val);
5677 static void perf_sample_regs_user(struct perf_regs *regs_user,
5678 struct pt_regs *regs,
5679 struct pt_regs *regs_user_copy)
5681 if (user_mode(regs)) {
5682 regs_user->abi = perf_reg_abi(current);
5683 regs_user->regs = regs;
5684 } else if (!(current->flags & PF_KTHREAD)) {
5685 perf_get_regs_user(regs_user, regs, regs_user_copy);
5687 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5688 regs_user->regs = NULL;
5692 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5693 struct pt_regs *regs)
5695 regs_intr->regs = regs;
5696 regs_intr->abi = perf_reg_abi(current);
5701 * Get remaining task size from user stack pointer.
5703 * It'd be better to take stack vma map and limit this more
5704 * precisly, but there's no way to get it safely under interrupt,
5705 * so using TASK_SIZE as limit.
5707 static u64 perf_ustack_task_size(struct pt_regs *regs)
5709 unsigned long addr = perf_user_stack_pointer(regs);
5711 if (!addr || addr >= TASK_SIZE)
5714 return TASK_SIZE - addr;
5718 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5719 struct pt_regs *regs)
5723 /* No regs, no stack pointer, no dump. */
5728 * Check if we fit in with the requested stack size into the:
5730 * If we don't, we limit the size to the TASK_SIZE.
5732 * - remaining sample size
5733 * If we don't, we customize the stack size to
5734 * fit in to the remaining sample size.
5737 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5738 stack_size = min(stack_size, (u16) task_size);
5740 /* Current header size plus static size and dynamic size. */
5741 header_size += 2 * sizeof(u64);
5743 /* Do we fit in with the current stack dump size? */
5744 if ((u16) (header_size + stack_size) < header_size) {
5746 * If we overflow the maximum size for the sample,
5747 * we customize the stack dump size to fit in.
5749 stack_size = USHRT_MAX - header_size - sizeof(u64);
5750 stack_size = round_up(stack_size, sizeof(u64));
5757 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5758 struct pt_regs *regs)
5760 /* Case of a kernel thread, nothing to dump */
5763 perf_output_put(handle, size);
5773 * - the size requested by user or the best one we can fit
5774 * in to the sample max size
5776 * - user stack dump data
5778 * - the actual dumped size
5782 perf_output_put(handle, dump_size);
5785 sp = perf_user_stack_pointer(regs);
5788 rem = __output_copy_user(handle, (void *) sp, dump_size);
5790 dyn_size = dump_size - rem;
5792 perf_output_skip(handle, rem);
5795 perf_output_put(handle, dyn_size);
5799 static void __perf_event_header__init_id(struct perf_event_header *header,
5800 struct perf_sample_data *data,
5801 struct perf_event *event,
5804 data->type = event->attr.sample_type;
5805 header->size += event->id_header_size;
5807 if (sample_type & PERF_SAMPLE_TID) {
5808 /* namespace issues */
5809 data->tid_entry.pid = perf_event_pid(event, current);
5810 data->tid_entry.tid = perf_event_tid(event, current);
5813 if (sample_type & PERF_SAMPLE_TIME)
5814 data->time = perf_event_clock(event);
5816 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5817 data->id = primary_event_id(event);
5819 if (sample_type & PERF_SAMPLE_STREAM_ID)
5820 data->stream_id = event->id;
5822 if (sample_type & PERF_SAMPLE_CPU) {
5823 data->cpu_entry.cpu = raw_smp_processor_id();
5824 data->cpu_entry.reserved = 0;
5828 void perf_event_header__init_id(struct perf_event_header *header,
5829 struct perf_sample_data *data,
5830 struct perf_event *event)
5832 if (event->attr.sample_id_all)
5833 __perf_event_header__init_id(header, data, event, event->attr.sample_type);
5836 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5837 struct perf_sample_data *data)
5839 u64 sample_type = data->type;
5841 if (sample_type & PERF_SAMPLE_TID)
5842 perf_output_put(handle, data->tid_entry);
5844 if (sample_type & PERF_SAMPLE_TIME)
5845 perf_output_put(handle, data->time);
5847 if (sample_type & PERF_SAMPLE_ID)
5848 perf_output_put(handle, data->id);
5850 if (sample_type & PERF_SAMPLE_STREAM_ID)
5851 perf_output_put(handle, data->stream_id);
5853 if (sample_type & PERF_SAMPLE_CPU)
5854 perf_output_put(handle, data->cpu_entry);
5856 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5857 perf_output_put(handle, data->id);
5860 void perf_event__output_id_sample(struct perf_event *event,
5861 struct perf_output_handle *handle,
5862 struct perf_sample_data *sample)
5864 if (event->attr.sample_id_all)
5865 __perf_event__output_id_sample(handle, sample);
5868 static void perf_output_read_one(struct perf_output_handle *handle,
5869 struct perf_event *event,
5870 u64 enabled, u64 running)
5872 u64 read_format = event->attr.read_format;
5876 values[n++] = perf_event_count(event);
5877 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5878 values[n++] = enabled +
5879 atomic64_read(&event->child_total_time_enabled);
5881 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5882 values[n++] = running +
5883 atomic64_read(&event->child_total_time_running);
5885 if (read_format & PERF_FORMAT_ID)
5886 values[n++] = primary_event_id(event);
5888 __output_copy(handle, values, n * sizeof(u64));
5891 static void perf_output_read_group(struct perf_output_handle *handle,
5892 struct perf_event *event,
5893 u64 enabled, u64 running)
5895 struct perf_event *leader = event->group_leader, *sub;
5896 u64 read_format = event->attr.read_format;
5900 values[n++] = 1 + leader->nr_siblings;
5902 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5903 values[n++] = enabled;
5905 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5906 values[n++] = running;
5908 if ((leader != event) &&
5909 (leader->state == PERF_EVENT_STATE_ACTIVE))
5910 leader->pmu->read(leader);
5912 values[n++] = perf_event_count(leader);
5913 if (read_format & PERF_FORMAT_ID)
5914 values[n++] = primary_event_id(leader);
5916 __output_copy(handle, values, n * sizeof(u64));
5918 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5921 if ((sub != event) &&
5922 (sub->state == PERF_EVENT_STATE_ACTIVE))
5923 sub->pmu->read(sub);
5925 values[n++] = perf_event_count(sub);
5926 if (read_format & PERF_FORMAT_ID)
5927 values[n++] = primary_event_id(sub);
5929 __output_copy(handle, values, n * sizeof(u64));
5933 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5934 PERF_FORMAT_TOTAL_TIME_RUNNING)
5937 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5939 * The problem is that its both hard and excessively expensive to iterate the
5940 * child list, not to mention that its impossible to IPI the children running
5941 * on another CPU, from interrupt/NMI context.
5943 static void perf_output_read(struct perf_output_handle *handle,
5944 struct perf_event *event)
5946 u64 enabled = 0, running = 0, now;
5947 u64 read_format = event->attr.read_format;
5950 * compute total_time_enabled, total_time_running
5951 * based on snapshot values taken when the event
5952 * was last scheduled in.
5954 * we cannot simply called update_context_time()
5955 * because of locking issue as we are called in
5958 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5959 calc_timer_values(event, &now, &enabled, &running);
5961 if (event->attr.read_format & PERF_FORMAT_GROUP)
5962 perf_output_read_group(handle, event, enabled, running);
5964 perf_output_read_one(handle, event, enabled, running);
5967 void perf_output_sample(struct perf_output_handle *handle,
5968 struct perf_event_header *header,
5969 struct perf_sample_data *data,
5970 struct perf_event *event)
5972 u64 sample_type = data->type;
5974 perf_output_put(handle, *header);
5976 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5977 perf_output_put(handle, data->id);
5979 if (sample_type & PERF_SAMPLE_IP)
5980 perf_output_put(handle, data->ip);
5982 if (sample_type & PERF_SAMPLE_TID)
5983 perf_output_put(handle, data->tid_entry);
5985 if (sample_type & PERF_SAMPLE_TIME)
5986 perf_output_put(handle, data->time);
5988 if (sample_type & PERF_SAMPLE_ADDR)
5989 perf_output_put(handle, data->addr);
5991 if (sample_type & PERF_SAMPLE_ID)
5992 perf_output_put(handle, data->id);
5994 if (sample_type & PERF_SAMPLE_STREAM_ID)
5995 perf_output_put(handle, data->stream_id);
5997 if (sample_type & PERF_SAMPLE_CPU)
5998 perf_output_put(handle, data->cpu_entry);
6000 if (sample_type & PERF_SAMPLE_PERIOD)
6001 perf_output_put(handle, data->period);
6003 if (sample_type & PERF_SAMPLE_READ)
6004 perf_output_read(handle, event);
6006 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6007 if (data->callchain) {
6010 if (data->callchain)
6011 size += data->callchain->nr;
6013 size *= sizeof(u64);
6015 __output_copy(handle, data->callchain, size);
6018 perf_output_put(handle, nr);
6022 if (sample_type & PERF_SAMPLE_RAW) {
6023 struct perf_raw_record *raw = data->raw;
6026 struct perf_raw_frag *frag = &raw->frag;
6028 perf_output_put(handle, raw->size);
6031 __output_custom(handle, frag->copy,
6032 frag->data, frag->size);
6034 __output_copy(handle, frag->data,
6037 if (perf_raw_frag_last(frag))
6042 __output_skip(handle, NULL, frag->pad);
6048 .size = sizeof(u32),
6051 perf_output_put(handle, raw);
6055 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6056 if (data->br_stack) {
6059 size = data->br_stack->nr
6060 * sizeof(struct perf_branch_entry);
6062 perf_output_put(handle, data->br_stack->nr);
6063 perf_output_copy(handle, data->br_stack->entries, size);
6066 * we always store at least the value of nr
6069 perf_output_put(handle, nr);
6073 if (sample_type & PERF_SAMPLE_REGS_USER) {
6074 u64 abi = data->regs_user.abi;
6077 * If there are no regs to dump, notice it through
6078 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6080 perf_output_put(handle, abi);
6083 u64 mask = event->attr.sample_regs_user;
6084 perf_output_sample_regs(handle,
6085 data->regs_user.regs,
6090 if (sample_type & PERF_SAMPLE_STACK_USER) {
6091 perf_output_sample_ustack(handle,
6092 data->stack_user_size,
6093 data->regs_user.regs);
6096 if (sample_type & PERF_SAMPLE_WEIGHT)
6097 perf_output_put(handle, data->weight);
6099 if (sample_type & PERF_SAMPLE_DATA_SRC)
6100 perf_output_put(handle, data->data_src.val);
6102 if (sample_type & PERF_SAMPLE_TRANSACTION)
6103 perf_output_put(handle, data->txn);
6105 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6106 u64 abi = data->regs_intr.abi;
6108 * If there are no regs to dump, notice it through
6109 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6111 perf_output_put(handle, abi);
6114 u64 mask = event->attr.sample_regs_intr;
6116 perf_output_sample_regs(handle,
6117 data->regs_intr.regs,
6122 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6123 perf_output_put(handle, data->phys_addr);
6125 if (!event->attr.watermark) {
6126 int wakeup_events = event->attr.wakeup_events;
6128 if (wakeup_events) {
6129 struct ring_buffer *rb = handle->rb;
6130 int events = local_inc_return(&rb->events);
6132 if (events >= wakeup_events) {
6133 local_sub(wakeup_events, &rb->events);
6134 local_inc(&rb->wakeup);
6140 static u64 perf_virt_to_phys(u64 virt)
6147 if (virt >= TASK_SIZE) {
6148 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6149 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6150 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6151 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6154 * Walking the pages tables for user address.
6155 * Interrupts are disabled, so it prevents any tear down
6156 * of the page tables.
6157 * Try IRQ-safe __get_user_pages_fast first.
6158 * If failed, leave phys_addr as 0.
6160 if (current->mm != NULL) {
6163 pagefault_disable();
6164 if (__get_user_pages_fast(virt, 1, 0, &p) == 1) {
6165 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6175 void perf_prepare_sample(struct perf_event_header *header,
6176 struct perf_sample_data *data,
6177 struct perf_event *event,
6178 struct pt_regs *regs)
6180 u64 sample_type = event->attr.sample_type;
6181 u64 filtered_sample_type;
6183 header->type = PERF_RECORD_SAMPLE;
6184 header->size = sizeof(*header) + event->header_size;
6187 header->misc |= perf_misc_flags(regs);
6190 * Clear the sample flags that have already been done by the
6193 filtered_sample_type = sample_type & ~data->sample_flags;
6194 __perf_event_header__init_id(header, data, event, filtered_sample_type);
6196 if (sample_type & PERF_SAMPLE_IP)
6197 data->ip = perf_instruction_pointer(regs);
6199 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6202 data->callchain = perf_callchain(event, regs);
6204 if (data->callchain)
6205 size += data->callchain->nr;
6207 header->size += size * sizeof(u64);
6210 if (sample_type & PERF_SAMPLE_RAW) {
6211 struct perf_raw_record *raw = data->raw;
6215 struct perf_raw_frag *frag = &raw->frag;
6220 if (perf_raw_frag_last(frag))
6225 size = round_up(sum + sizeof(u32), sizeof(u64));
6226 raw->size = size - sizeof(u32);
6227 frag->pad = raw->size - sum;
6232 header->size += size;
6235 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6236 int size = sizeof(u64); /* nr */
6237 if (data->br_stack) {
6238 size += data->br_stack->nr
6239 * sizeof(struct perf_branch_entry);
6241 header->size += size;
6244 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6245 perf_sample_regs_user(&data->regs_user, regs,
6246 &data->regs_user_copy);
6248 if (sample_type & PERF_SAMPLE_REGS_USER) {
6249 /* regs dump ABI info */
6250 int size = sizeof(u64);
6252 if (data->regs_user.regs) {
6253 u64 mask = event->attr.sample_regs_user;
6254 size += hweight64(mask) * sizeof(u64);
6257 header->size += size;
6260 if (sample_type & PERF_SAMPLE_STACK_USER) {
6262 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6263 * processed as the last one or have additional check added
6264 * in case new sample type is added, because we could eat
6265 * up the rest of the sample size.
6267 u16 stack_size = event->attr.sample_stack_user;
6268 u16 size = sizeof(u64);
6270 stack_size = perf_sample_ustack_size(stack_size, header->size,
6271 data->regs_user.regs);
6274 * If there is something to dump, add space for the dump
6275 * itself and for the field that tells the dynamic size,
6276 * which is how many have been actually dumped.
6279 size += sizeof(u64) + stack_size;
6281 data->stack_user_size = stack_size;
6282 header->size += size;
6285 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6286 /* regs dump ABI info */
6287 int size = sizeof(u64);
6289 perf_sample_regs_intr(&data->regs_intr, regs);
6291 if (data->regs_intr.regs) {
6292 u64 mask = event->attr.sample_regs_intr;
6294 size += hweight64(mask) * sizeof(u64);
6297 header->size += size;
6300 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6301 data->phys_addr = perf_virt_to_phys(data->addr);
6304 static void __always_inline
6305 __perf_event_output(struct perf_event *event,
6306 struct perf_sample_data *data,
6307 struct pt_regs *regs,
6308 int (*output_begin)(struct perf_output_handle *,
6309 struct perf_event *,
6312 struct perf_output_handle handle;
6313 struct perf_event_header header;
6315 /* protect the callchain buffers */
6318 perf_prepare_sample(&header, data, event, regs);
6320 if (output_begin(&handle, event, header.size))
6323 perf_output_sample(&handle, &header, data, event);
6325 perf_output_end(&handle);
6332 perf_event_output_forward(struct perf_event *event,
6333 struct perf_sample_data *data,
6334 struct pt_regs *regs)
6336 __perf_event_output(event, data, regs, perf_output_begin_forward);
6340 perf_event_output_backward(struct perf_event *event,
6341 struct perf_sample_data *data,
6342 struct pt_regs *regs)
6344 __perf_event_output(event, data, regs, perf_output_begin_backward);
6348 perf_event_output(struct perf_event *event,
6349 struct perf_sample_data *data,
6350 struct pt_regs *regs)
6352 __perf_event_output(event, data, regs, perf_output_begin);
6359 struct perf_read_event {
6360 struct perf_event_header header;
6367 perf_event_read_event(struct perf_event *event,
6368 struct task_struct *task)
6370 struct perf_output_handle handle;
6371 struct perf_sample_data sample;
6372 struct perf_read_event read_event = {
6374 .type = PERF_RECORD_READ,
6376 .size = sizeof(read_event) + event->read_size,
6378 .pid = perf_event_pid(event, task),
6379 .tid = perf_event_tid(event, task),
6383 perf_event_header__init_id(&read_event.header, &sample, event);
6384 ret = perf_output_begin(&handle, event, read_event.header.size);
6388 perf_output_put(&handle, read_event);
6389 perf_output_read(&handle, event);
6390 perf_event__output_id_sample(event, &handle, &sample);
6392 perf_output_end(&handle);
6395 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6398 perf_iterate_ctx(struct perf_event_context *ctx,
6399 perf_iterate_f output,
6400 void *data, bool all)
6402 struct perf_event *event;
6404 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6406 if (event->state < PERF_EVENT_STATE_INACTIVE)
6408 if (!event_filter_match(event))
6412 output(event, data);
6416 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6418 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6419 struct perf_event *event;
6421 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6423 * Skip events that are not fully formed yet; ensure that
6424 * if we observe event->ctx, both event and ctx will be
6425 * complete enough. See perf_install_in_context().
6427 if (!smp_load_acquire(&event->ctx))
6430 if (event->state < PERF_EVENT_STATE_INACTIVE)
6432 if (!event_filter_match(event))
6434 output(event, data);
6439 * Iterate all events that need to receive side-band events.
6441 * For new callers; ensure that account_pmu_sb_event() includes
6442 * your event, otherwise it might not get delivered.
6445 perf_iterate_sb(perf_iterate_f output, void *data,
6446 struct perf_event_context *task_ctx)
6448 struct perf_event_context *ctx;
6455 * If we have task_ctx != NULL we only notify the task context itself.
6456 * The task_ctx is set only for EXIT events before releasing task
6460 perf_iterate_ctx(task_ctx, output, data, false);
6464 perf_iterate_sb_cpu(output, data);
6466 for_each_task_context_nr(ctxn) {
6467 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6469 perf_iterate_ctx(ctx, output, data, false);
6477 * Clear all file-based filters at exec, they'll have to be
6478 * re-instated when/if these objects are mmapped again.
6480 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6482 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6483 struct perf_addr_filter *filter;
6484 unsigned int restart = 0, count = 0;
6485 unsigned long flags;
6487 if (!has_addr_filter(event))
6490 raw_spin_lock_irqsave(&ifh->lock, flags);
6491 list_for_each_entry(filter, &ifh->list, entry) {
6492 if (filter->path.dentry) {
6493 event->addr_filters_offs[count] = 0;
6501 event->addr_filters_gen++;
6502 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6505 perf_event_stop(event, 1);
6508 void perf_event_exec(void)
6510 struct perf_event_context *ctx;
6514 for_each_task_context_nr(ctxn) {
6515 ctx = current->perf_event_ctxp[ctxn];
6519 perf_event_enable_on_exec(ctxn);
6521 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6527 struct remote_output {
6528 struct ring_buffer *rb;
6532 static void __perf_event_output_stop(struct perf_event *event, void *data)
6534 struct perf_event *parent = event->parent;
6535 struct remote_output *ro = data;
6536 struct ring_buffer *rb = ro->rb;
6537 struct stop_event_data sd = {
6541 if (!has_aux(event))
6548 * In case of inheritance, it will be the parent that links to the
6549 * ring-buffer, but it will be the child that's actually using it.
6551 * We are using event::rb to determine if the event should be stopped,
6552 * however this may race with ring_buffer_attach() (through set_output),
6553 * which will make us skip the event that actually needs to be stopped.
6554 * So ring_buffer_attach() has to stop an aux event before re-assigning
6557 if (rcu_dereference(parent->rb) == rb)
6558 ro->err = __perf_event_stop(&sd);
6561 static int __perf_pmu_output_stop(void *info)
6563 struct perf_event *event = info;
6564 struct pmu *pmu = event->pmu;
6565 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6566 struct remote_output ro = {
6571 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6572 if (cpuctx->task_ctx)
6573 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6580 static void perf_pmu_output_stop(struct perf_event *event)
6582 struct perf_event *iter;
6587 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6589 * For per-CPU events, we need to make sure that neither they
6590 * nor their children are running; for cpu==-1 events it's
6591 * sufficient to stop the event itself if it's active, since
6592 * it can't have children.
6596 cpu = READ_ONCE(iter->oncpu);
6601 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6602 if (err == -EAGAIN) {
6611 * task tracking -- fork/exit
6613 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6616 struct perf_task_event {
6617 struct task_struct *task;
6618 struct perf_event_context *task_ctx;
6621 struct perf_event_header header;
6631 static int perf_event_task_match(struct perf_event *event)
6633 return event->attr.comm || event->attr.mmap ||
6634 event->attr.mmap2 || event->attr.mmap_data ||
6638 static void perf_event_task_output(struct perf_event *event,
6641 struct perf_task_event *task_event = data;
6642 struct perf_output_handle handle;
6643 struct perf_sample_data sample;
6644 struct task_struct *task = task_event->task;
6645 int ret, size = task_event->event_id.header.size;
6647 if (!perf_event_task_match(event))
6650 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6652 ret = perf_output_begin(&handle, event,
6653 task_event->event_id.header.size);
6657 task_event->event_id.pid = perf_event_pid(event, task);
6658 task_event->event_id.tid = perf_event_tid(event, task);
6660 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
6661 task_event->event_id.ppid = perf_event_pid(event,
6663 task_event->event_id.ptid = perf_event_pid(event,
6665 } else { /* PERF_RECORD_FORK */
6666 task_event->event_id.ppid = perf_event_pid(event, current);
6667 task_event->event_id.ptid = perf_event_tid(event, current);
6670 task_event->event_id.time = perf_event_clock(event);
6672 perf_output_put(&handle, task_event->event_id);
6674 perf_event__output_id_sample(event, &handle, &sample);
6676 perf_output_end(&handle);
6678 task_event->event_id.header.size = size;
6681 static void perf_event_task(struct task_struct *task,
6682 struct perf_event_context *task_ctx,
6685 struct perf_task_event task_event;
6687 if (!atomic_read(&nr_comm_events) &&
6688 !atomic_read(&nr_mmap_events) &&
6689 !atomic_read(&nr_task_events))
6692 task_event = (struct perf_task_event){
6694 .task_ctx = task_ctx,
6697 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6699 .size = sizeof(task_event.event_id),
6709 perf_iterate_sb(perf_event_task_output,
6714 void perf_event_fork(struct task_struct *task)
6716 perf_event_task(task, NULL, 1);
6717 perf_event_namespaces(task);
6724 struct perf_comm_event {
6725 struct task_struct *task;
6730 struct perf_event_header header;
6737 static int perf_event_comm_match(struct perf_event *event)
6739 return event->attr.comm;
6742 static void perf_event_comm_output(struct perf_event *event,
6745 struct perf_comm_event *comm_event = data;
6746 struct perf_output_handle handle;
6747 struct perf_sample_data sample;
6748 int size = comm_event->event_id.header.size;
6751 if (!perf_event_comm_match(event))
6754 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6755 ret = perf_output_begin(&handle, event,
6756 comm_event->event_id.header.size);
6761 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6762 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6764 perf_output_put(&handle, comm_event->event_id);
6765 __output_copy(&handle, comm_event->comm,
6766 comm_event->comm_size);
6768 perf_event__output_id_sample(event, &handle, &sample);
6770 perf_output_end(&handle);
6772 comm_event->event_id.header.size = size;
6775 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6777 char comm[TASK_COMM_LEN];
6780 memset(comm, 0, sizeof(comm));
6781 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6782 size = ALIGN(strlen(comm)+1, sizeof(u64));
6784 comm_event->comm = comm;
6785 comm_event->comm_size = size;
6787 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6789 perf_iterate_sb(perf_event_comm_output,
6794 void perf_event_comm(struct task_struct *task, bool exec)
6796 struct perf_comm_event comm_event;
6798 if (!atomic_read(&nr_comm_events))
6801 comm_event = (struct perf_comm_event){
6807 .type = PERF_RECORD_COMM,
6808 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6816 perf_event_comm_event(&comm_event);
6820 * namespaces tracking
6823 struct perf_namespaces_event {
6824 struct task_struct *task;
6827 struct perf_event_header header;
6832 struct perf_ns_link_info link_info[NR_NAMESPACES];
6836 static int perf_event_namespaces_match(struct perf_event *event)
6838 return event->attr.namespaces;
6841 static void perf_event_namespaces_output(struct perf_event *event,
6844 struct perf_namespaces_event *namespaces_event = data;
6845 struct perf_output_handle handle;
6846 struct perf_sample_data sample;
6847 u16 header_size = namespaces_event->event_id.header.size;
6850 if (!perf_event_namespaces_match(event))
6853 perf_event_header__init_id(&namespaces_event->event_id.header,
6855 ret = perf_output_begin(&handle, event,
6856 namespaces_event->event_id.header.size);
6860 namespaces_event->event_id.pid = perf_event_pid(event,
6861 namespaces_event->task);
6862 namespaces_event->event_id.tid = perf_event_tid(event,
6863 namespaces_event->task);
6865 perf_output_put(&handle, namespaces_event->event_id);
6867 perf_event__output_id_sample(event, &handle, &sample);
6869 perf_output_end(&handle);
6871 namespaces_event->event_id.header.size = header_size;
6874 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6875 struct task_struct *task,
6876 const struct proc_ns_operations *ns_ops)
6878 struct path ns_path;
6879 struct inode *ns_inode;
6882 error = ns_get_path(&ns_path, task, ns_ops);
6884 ns_inode = ns_path.dentry->d_inode;
6885 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6886 ns_link_info->ino = ns_inode->i_ino;
6891 void perf_event_namespaces(struct task_struct *task)
6893 struct perf_namespaces_event namespaces_event;
6894 struct perf_ns_link_info *ns_link_info;
6896 if (!atomic_read(&nr_namespaces_events))
6899 namespaces_event = (struct perf_namespaces_event){
6903 .type = PERF_RECORD_NAMESPACES,
6905 .size = sizeof(namespaces_event.event_id),
6909 .nr_namespaces = NR_NAMESPACES,
6910 /* .link_info[NR_NAMESPACES] */
6914 ns_link_info = namespaces_event.event_id.link_info;
6916 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6917 task, &mntns_operations);
6919 #ifdef CONFIG_USER_NS
6920 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6921 task, &userns_operations);
6923 #ifdef CONFIG_NET_NS
6924 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6925 task, &netns_operations);
6927 #ifdef CONFIG_UTS_NS
6928 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6929 task, &utsns_operations);
6931 #ifdef CONFIG_IPC_NS
6932 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6933 task, &ipcns_operations);
6935 #ifdef CONFIG_PID_NS
6936 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6937 task, &pidns_operations);
6939 #ifdef CONFIG_CGROUPS
6940 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6941 task, &cgroupns_operations);
6944 perf_iterate_sb(perf_event_namespaces_output,
6953 struct perf_mmap_event {
6954 struct vm_area_struct *vma;
6956 const char *file_name;
6964 struct perf_event_header header;
6974 static int perf_event_mmap_match(struct perf_event *event,
6977 struct perf_mmap_event *mmap_event = data;
6978 struct vm_area_struct *vma = mmap_event->vma;
6979 int executable = vma->vm_flags & VM_EXEC;
6981 return (!executable && event->attr.mmap_data) ||
6982 (executable && (event->attr.mmap || event->attr.mmap2));
6985 static void perf_event_mmap_output(struct perf_event *event,
6988 struct perf_mmap_event *mmap_event = data;
6989 struct perf_output_handle handle;
6990 struct perf_sample_data sample;
6991 int size = mmap_event->event_id.header.size;
6992 u32 type = mmap_event->event_id.header.type;
6995 if (!perf_event_mmap_match(event, data))
6998 if (event->attr.mmap2) {
6999 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7000 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7001 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7002 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7003 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7004 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7005 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7008 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7009 ret = perf_output_begin(&handle, event,
7010 mmap_event->event_id.header.size);
7014 mmap_event->event_id.pid = perf_event_pid(event, current);
7015 mmap_event->event_id.tid = perf_event_tid(event, current);
7017 perf_output_put(&handle, mmap_event->event_id);
7019 if (event->attr.mmap2) {
7020 perf_output_put(&handle, mmap_event->maj);
7021 perf_output_put(&handle, mmap_event->min);
7022 perf_output_put(&handle, mmap_event->ino);
7023 perf_output_put(&handle, mmap_event->ino_generation);
7024 perf_output_put(&handle, mmap_event->prot);
7025 perf_output_put(&handle, mmap_event->flags);
7028 __output_copy(&handle, mmap_event->file_name,
7029 mmap_event->file_size);
7031 perf_event__output_id_sample(event, &handle, &sample);
7033 perf_output_end(&handle);
7035 mmap_event->event_id.header.size = size;
7036 mmap_event->event_id.header.type = type;
7039 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7041 struct vm_area_struct *vma = mmap_event->vma;
7042 struct file *file = vma->vm_file;
7043 int maj = 0, min = 0;
7044 u64 ino = 0, gen = 0;
7045 u32 prot = 0, flags = 0;
7051 if (vma->vm_flags & VM_READ)
7053 if (vma->vm_flags & VM_WRITE)
7055 if (vma->vm_flags & VM_EXEC)
7058 if (vma->vm_flags & VM_MAYSHARE)
7061 flags = MAP_PRIVATE;
7063 if (vma->vm_flags & VM_DENYWRITE)
7064 flags |= MAP_DENYWRITE;
7065 if (vma->vm_flags & VM_MAYEXEC)
7066 flags |= MAP_EXECUTABLE;
7067 if (vma->vm_flags & VM_LOCKED)
7068 flags |= MAP_LOCKED;
7069 if (vma->vm_flags & VM_HUGETLB)
7070 flags |= MAP_HUGETLB;
7073 struct inode *inode;
7076 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7082 * d_path() works from the end of the rb backwards, so we
7083 * need to add enough zero bytes after the string to handle
7084 * the 64bit alignment we do later.
7086 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7091 inode = file_inode(vma->vm_file);
7092 dev = inode->i_sb->s_dev;
7094 gen = inode->i_generation;
7100 if (vma->vm_ops && vma->vm_ops->name) {
7101 name = (char *) vma->vm_ops->name(vma);
7106 name = (char *)arch_vma_name(vma);
7110 if (vma->vm_start <= vma->vm_mm->start_brk &&
7111 vma->vm_end >= vma->vm_mm->brk) {
7115 if (vma->vm_start <= vma->vm_mm->start_stack &&
7116 vma->vm_end >= vma->vm_mm->start_stack) {
7126 strlcpy(tmp, name, sizeof(tmp));
7130 * Since our buffer works in 8 byte units we need to align our string
7131 * size to a multiple of 8. However, we must guarantee the tail end is
7132 * zero'd out to avoid leaking random bits to userspace.
7134 size = strlen(name)+1;
7135 while (!IS_ALIGNED(size, sizeof(u64)))
7136 name[size++] = '\0';
7138 mmap_event->file_name = name;
7139 mmap_event->file_size = size;
7140 mmap_event->maj = maj;
7141 mmap_event->min = min;
7142 mmap_event->ino = ino;
7143 mmap_event->ino_generation = gen;
7144 mmap_event->prot = prot;
7145 mmap_event->flags = flags;
7147 if (!(vma->vm_flags & VM_EXEC))
7148 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7150 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7152 perf_iterate_sb(perf_event_mmap_output,
7160 * Check whether inode and address range match filter criteria.
7162 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7163 struct file *file, unsigned long offset,
7166 /* d_inode(NULL) won't be equal to any mapped user-space file */
7167 if (!filter->path.dentry)
7170 if (d_inode(filter->path.dentry) != file_inode(file))
7173 if (filter->offset > offset + size)
7176 if (filter->offset + filter->size < offset)
7182 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7184 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7185 struct vm_area_struct *vma = data;
7186 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7187 struct file *file = vma->vm_file;
7188 struct perf_addr_filter *filter;
7189 unsigned int restart = 0, count = 0;
7191 if (!has_addr_filter(event))
7197 raw_spin_lock_irqsave(&ifh->lock, flags);
7198 list_for_each_entry(filter, &ifh->list, entry) {
7199 if (perf_addr_filter_match(filter, file, off,
7200 vma->vm_end - vma->vm_start)) {
7201 event->addr_filters_offs[count] = vma->vm_start;
7209 event->addr_filters_gen++;
7210 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7213 perf_event_stop(event, 1);
7217 * Adjust all task's events' filters to the new vma
7219 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7221 struct perf_event_context *ctx;
7225 * Data tracing isn't supported yet and as such there is no need
7226 * to keep track of anything that isn't related to executable code:
7228 if (!(vma->vm_flags & VM_EXEC))
7232 for_each_task_context_nr(ctxn) {
7233 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7237 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7242 void perf_event_mmap(struct vm_area_struct *vma)
7244 struct perf_mmap_event mmap_event;
7246 if (!atomic_read(&nr_mmap_events))
7249 mmap_event = (struct perf_mmap_event){
7255 .type = PERF_RECORD_MMAP,
7256 .misc = PERF_RECORD_MISC_USER,
7261 .start = vma->vm_start,
7262 .len = vma->vm_end - vma->vm_start,
7263 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7265 /* .maj (attr_mmap2 only) */
7266 /* .min (attr_mmap2 only) */
7267 /* .ino (attr_mmap2 only) */
7268 /* .ino_generation (attr_mmap2 only) */
7269 /* .prot (attr_mmap2 only) */
7270 /* .flags (attr_mmap2 only) */
7273 perf_addr_filters_adjust(vma);
7274 perf_event_mmap_event(&mmap_event);
7277 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7278 unsigned long size, u64 flags)
7280 struct perf_output_handle handle;
7281 struct perf_sample_data sample;
7282 struct perf_aux_event {
7283 struct perf_event_header header;
7289 .type = PERF_RECORD_AUX,
7291 .size = sizeof(rec),
7299 perf_event_header__init_id(&rec.header, &sample, event);
7300 ret = perf_output_begin(&handle, event, rec.header.size);
7305 perf_output_put(&handle, rec);
7306 perf_event__output_id_sample(event, &handle, &sample);
7308 perf_output_end(&handle);
7312 * Lost/dropped samples logging
7314 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7316 struct perf_output_handle handle;
7317 struct perf_sample_data sample;
7321 struct perf_event_header header;
7323 } lost_samples_event = {
7325 .type = PERF_RECORD_LOST_SAMPLES,
7327 .size = sizeof(lost_samples_event),
7332 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7334 ret = perf_output_begin(&handle, event,
7335 lost_samples_event.header.size);
7339 perf_output_put(&handle, lost_samples_event);
7340 perf_event__output_id_sample(event, &handle, &sample);
7341 perf_output_end(&handle);
7345 * context_switch tracking
7348 struct perf_switch_event {
7349 struct task_struct *task;
7350 struct task_struct *next_prev;
7353 struct perf_event_header header;
7359 static int perf_event_switch_match(struct perf_event *event)
7361 return event->attr.context_switch;
7364 static void perf_event_switch_output(struct perf_event *event, void *data)
7366 struct perf_switch_event *se = data;
7367 struct perf_output_handle handle;
7368 struct perf_sample_data sample;
7371 if (!perf_event_switch_match(event))
7374 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7375 if (event->ctx->task) {
7376 se->event_id.header.type = PERF_RECORD_SWITCH;
7377 se->event_id.header.size = sizeof(se->event_id.header);
7379 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7380 se->event_id.header.size = sizeof(se->event_id);
7381 se->event_id.next_prev_pid =
7382 perf_event_pid(event, se->next_prev);
7383 se->event_id.next_prev_tid =
7384 perf_event_tid(event, se->next_prev);
7387 perf_event_header__init_id(&se->event_id.header, &sample, event);
7389 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7393 if (event->ctx->task)
7394 perf_output_put(&handle, se->event_id.header);
7396 perf_output_put(&handle, se->event_id);
7398 perf_event__output_id_sample(event, &handle, &sample);
7400 perf_output_end(&handle);
7403 static void perf_event_switch(struct task_struct *task,
7404 struct task_struct *next_prev, bool sched_in)
7406 struct perf_switch_event switch_event;
7408 /* N.B. caller checks nr_switch_events != 0 */
7410 switch_event = (struct perf_switch_event){
7412 .next_prev = next_prev,
7416 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7419 /* .next_prev_pid */
7420 /* .next_prev_tid */
7424 perf_iterate_sb(perf_event_switch_output,
7430 * IRQ throttle logging
7433 static void perf_log_throttle(struct perf_event *event, int enable)
7435 struct perf_output_handle handle;
7436 struct perf_sample_data sample;
7440 struct perf_event_header header;
7444 } throttle_event = {
7446 .type = PERF_RECORD_THROTTLE,
7448 .size = sizeof(throttle_event),
7450 .time = perf_event_clock(event),
7451 .id = primary_event_id(event),
7452 .stream_id = event->id,
7456 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7458 perf_event_header__init_id(&throttle_event.header, &sample, event);
7460 ret = perf_output_begin(&handle, event,
7461 throttle_event.header.size);
7465 perf_output_put(&handle, throttle_event);
7466 perf_event__output_id_sample(event, &handle, &sample);
7467 perf_output_end(&handle);
7470 void perf_event_itrace_started(struct perf_event *event)
7472 event->attach_state |= PERF_ATTACH_ITRACE;
7475 static void perf_log_itrace_start(struct perf_event *event)
7477 struct perf_output_handle handle;
7478 struct perf_sample_data sample;
7479 struct perf_aux_event {
7480 struct perf_event_header header;
7487 event = event->parent;
7489 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7490 event->attach_state & PERF_ATTACH_ITRACE)
7493 rec.header.type = PERF_RECORD_ITRACE_START;
7494 rec.header.misc = 0;
7495 rec.header.size = sizeof(rec);
7496 rec.pid = perf_event_pid(event, current);
7497 rec.tid = perf_event_tid(event, current);
7499 perf_event_header__init_id(&rec.header, &sample, event);
7500 ret = perf_output_begin(&handle, event, rec.header.size);
7505 perf_output_put(&handle, rec);
7506 perf_event__output_id_sample(event, &handle, &sample);
7508 perf_output_end(&handle);
7512 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7514 struct hw_perf_event *hwc = &event->hw;
7518 seq = __this_cpu_read(perf_throttled_seq);
7519 if (seq != hwc->interrupts_seq) {
7520 hwc->interrupts_seq = seq;
7521 hwc->interrupts = 1;
7524 if (unlikely(throttle &&
7525 hwc->interrupts > max_samples_per_tick)) {
7526 __this_cpu_inc(perf_throttled_count);
7527 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7528 hwc->interrupts = MAX_INTERRUPTS;
7529 perf_log_throttle(event, 0);
7534 if (event->attr.freq) {
7535 u64 now = perf_clock();
7536 s64 delta = now - hwc->freq_time_stamp;
7538 hwc->freq_time_stamp = now;
7540 if (delta > 0 && delta < 2*TICK_NSEC)
7541 perf_adjust_period(event, delta, hwc->last_period, true);
7547 int perf_event_account_interrupt(struct perf_event *event)
7549 return __perf_event_account_interrupt(event, 1);
7553 * Generic event overflow handling, sampling.
7556 static int __perf_event_overflow(struct perf_event *event,
7557 int throttle, struct perf_sample_data *data,
7558 struct pt_regs *regs)
7560 int events = atomic_read(&event->event_limit);
7564 * Non-sampling counters might still use the PMI to fold short
7565 * hardware counters, ignore those.
7567 if (unlikely(!is_sampling_event(event)))
7570 ret = __perf_event_account_interrupt(event, throttle);
7573 * XXX event_limit might not quite work as expected on inherited
7577 event->pending_kill = POLL_IN;
7578 if (events && atomic_dec_and_test(&event->event_limit)) {
7580 event->pending_kill = POLL_HUP;
7582 perf_event_disable_inatomic(event);
7585 READ_ONCE(event->overflow_handler)(event, data, regs);
7587 if (*perf_event_fasync(event) && event->pending_kill) {
7588 event->pending_wakeup = 1;
7589 irq_work_queue(&event->pending);
7595 int perf_event_overflow(struct perf_event *event,
7596 struct perf_sample_data *data,
7597 struct pt_regs *regs)
7599 return __perf_event_overflow(event, 1, data, regs);
7603 * Generic software event infrastructure
7606 struct swevent_htable {
7607 struct swevent_hlist *swevent_hlist;
7608 struct mutex hlist_mutex;
7611 /* Recursion avoidance in each contexts */
7612 int recursion[PERF_NR_CONTEXTS];
7615 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7618 * We directly increment event->count and keep a second value in
7619 * event->hw.period_left to count intervals. This period event
7620 * is kept in the range [-sample_period, 0] so that we can use the
7624 u64 perf_swevent_set_period(struct perf_event *event)
7626 struct hw_perf_event *hwc = &event->hw;
7627 u64 period = hwc->last_period;
7631 hwc->last_period = hwc->sample_period;
7634 old = val = local64_read(&hwc->period_left);
7638 nr = div64_u64(period + val, period);
7639 offset = nr * period;
7641 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7647 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7648 struct perf_sample_data *data,
7649 struct pt_regs *regs)
7651 struct hw_perf_event *hwc = &event->hw;
7655 overflow = perf_swevent_set_period(event);
7657 if (hwc->interrupts == MAX_INTERRUPTS)
7660 for (; overflow; overflow--) {
7661 if (__perf_event_overflow(event, throttle,
7664 * We inhibit the overflow from happening when
7665 * hwc->interrupts == MAX_INTERRUPTS.
7673 static void perf_swevent_event(struct perf_event *event, u64 nr,
7674 struct perf_sample_data *data,
7675 struct pt_regs *regs)
7677 struct hw_perf_event *hwc = &event->hw;
7679 local64_add(nr, &event->count);
7684 if (!is_sampling_event(event))
7687 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7689 return perf_swevent_overflow(event, 1, data, regs);
7691 data->period = event->hw.last_period;
7693 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7694 return perf_swevent_overflow(event, 1, data, regs);
7696 if (local64_add_negative(nr, &hwc->period_left))
7699 perf_swevent_overflow(event, 0, data, regs);
7702 static int perf_exclude_event(struct perf_event *event,
7703 struct pt_regs *regs)
7705 if (event->hw.state & PERF_HES_STOPPED)
7709 if (event->attr.exclude_user && user_mode(regs))
7712 if (event->attr.exclude_kernel && !user_mode(regs))
7719 static int perf_swevent_match(struct perf_event *event,
7720 enum perf_type_id type,
7722 struct perf_sample_data *data,
7723 struct pt_regs *regs)
7725 if (event->attr.type != type)
7728 if (event->attr.config != event_id)
7731 if (perf_exclude_event(event, regs))
7737 static inline u64 swevent_hash(u64 type, u32 event_id)
7739 u64 val = event_id | (type << 32);
7741 return hash_64(val, SWEVENT_HLIST_BITS);
7744 static inline struct hlist_head *
7745 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7747 u64 hash = swevent_hash(type, event_id);
7749 return &hlist->heads[hash];
7752 /* For the read side: events when they trigger */
7753 static inline struct hlist_head *
7754 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7756 struct swevent_hlist *hlist;
7758 hlist = rcu_dereference(swhash->swevent_hlist);
7762 return __find_swevent_head(hlist, type, event_id);
7765 /* For the event head insertion and removal in the hlist */
7766 static inline struct hlist_head *
7767 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7769 struct swevent_hlist *hlist;
7770 u32 event_id = event->attr.config;
7771 u64 type = event->attr.type;
7774 * Event scheduling is always serialized against hlist allocation
7775 * and release. Which makes the protected version suitable here.
7776 * The context lock guarantees that.
7778 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7779 lockdep_is_held(&event->ctx->lock));
7783 return __find_swevent_head(hlist, type, event_id);
7786 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7788 struct perf_sample_data *data,
7789 struct pt_regs *regs)
7791 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7792 struct perf_event *event;
7793 struct hlist_head *head;
7796 head = find_swevent_head_rcu(swhash, type, event_id);
7800 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7801 if (perf_swevent_match(event, type, event_id, data, regs))
7802 perf_swevent_event(event, nr, data, regs);
7808 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7810 int perf_swevent_get_recursion_context(void)
7812 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7814 return get_recursion_context(swhash->recursion);
7816 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7818 void perf_swevent_put_recursion_context(int rctx)
7820 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7822 put_recursion_context(swhash->recursion, rctx);
7825 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7827 struct perf_sample_data data;
7829 if (WARN_ON_ONCE(!regs))
7832 perf_sample_data_init(&data, addr, 0);
7833 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7836 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7840 preempt_disable_notrace();
7841 rctx = perf_swevent_get_recursion_context();
7842 if (unlikely(rctx < 0))
7845 ___perf_sw_event(event_id, nr, regs, addr);
7847 perf_swevent_put_recursion_context(rctx);
7849 preempt_enable_notrace();
7852 static void perf_swevent_read(struct perf_event *event)
7856 static int perf_swevent_add(struct perf_event *event, int flags)
7858 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7859 struct hw_perf_event *hwc = &event->hw;
7860 struct hlist_head *head;
7862 if (is_sampling_event(event)) {
7863 hwc->last_period = hwc->sample_period;
7864 perf_swevent_set_period(event);
7867 hwc->state = !(flags & PERF_EF_START);
7869 head = find_swevent_head(swhash, event);
7870 if (WARN_ON_ONCE(!head))
7873 hlist_add_head_rcu(&event->hlist_entry, head);
7874 perf_event_update_userpage(event);
7879 static void perf_swevent_del(struct perf_event *event, int flags)
7881 hlist_del_rcu(&event->hlist_entry);
7884 static void perf_swevent_start(struct perf_event *event, int flags)
7886 event->hw.state = 0;
7889 static void perf_swevent_stop(struct perf_event *event, int flags)
7891 event->hw.state = PERF_HES_STOPPED;
7894 /* Deref the hlist from the update side */
7895 static inline struct swevent_hlist *
7896 swevent_hlist_deref(struct swevent_htable *swhash)
7898 return rcu_dereference_protected(swhash->swevent_hlist,
7899 lockdep_is_held(&swhash->hlist_mutex));
7902 static void swevent_hlist_release(struct swevent_htable *swhash)
7904 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7909 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7910 kfree_rcu(hlist, rcu_head);
7913 static void swevent_hlist_put_cpu(int cpu)
7915 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7917 mutex_lock(&swhash->hlist_mutex);
7919 if (!--swhash->hlist_refcount)
7920 swevent_hlist_release(swhash);
7922 mutex_unlock(&swhash->hlist_mutex);
7925 static void swevent_hlist_put(void)
7929 for_each_possible_cpu(cpu)
7930 swevent_hlist_put_cpu(cpu);
7933 static int swevent_hlist_get_cpu(int cpu)
7935 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7938 mutex_lock(&swhash->hlist_mutex);
7939 if (!swevent_hlist_deref(swhash) &&
7940 cpumask_test_cpu(cpu, perf_online_mask)) {
7941 struct swevent_hlist *hlist;
7943 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7948 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7950 swhash->hlist_refcount++;
7952 mutex_unlock(&swhash->hlist_mutex);
7957 static int swevent_hlist_get(void)
7959 int err, cpu, failed_cpu;
7961 mutex_lock(&pmus_lock);
7962 for_each_possible_cpu(cpu) {
7963 err = swevent_hlist_get_cpu(cpu);
7969 mutex_unlock(&pmus_lock);
7972 for_each_possible_cpu(cpu) {
7973 if (cpu == failed_cpu)
7975 swevent_hlist_put_cpu(cpu);
7977 mutex_unlock(&pmus_lock);
7981 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7983 static void sw_perf_event_destroy(struct perf_event *event)
7985 u64 event_id = event->attr.config;
7987 WARN_ON(event->parent);
7989 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7990 swevent_hlist_put();
7993 static int perf_swevent_init(struct perf_event *event)
7995 u64 event_id = event->attr.config;
7997 if (event->attr.type != PERF_TYPE_SOFTWARE)
8001 * no branch sampling for software events
8003 if (has_branch_stack(event))
8007 case PERF_COUNT_SW_CPU_CLOCK:
8008 case PERF_COUNT_SW_TASK_CLOCK:
8015 if (event_id >= PERF_COUNT_SW_MAX)
8018 if (!event->parent) {
8021 err = swevent_hlist_get();
8025 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8026 event->destroy = sw_perf_event_destroy;
8032 static struct pmu perf_swevent = {
8033 .task_ctx_nr = perf_sw_context,
8035 .capabilities = PERF_PMU_CAP_NO_NMI,
8037 .event_init = perf_swevent_init,
8038 .add = perf_swevent_add,
8039 .del = perf_swevent_del,
8040 .start = perf_swevent_start,
8041 .stop = perf_swevent_stop,
8042 .read = perf_swevent_read,
8045 #ifdef CONFIG_EVENT_TRACING
8047 static int perf_tp_filter_match(struct perf_event *event,
8048 struct perf_sample_data *data)
8050 void *record = data->raw->frag.data;
8052 /* only top level events have filters set */
8054 event = event->parent;
8056 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8061 static int perf_tp_event_match(struct perf_event *event,
8062 struct perf_sample_data *data,
8063 struct pt_regs *regs)
8065 if (event->hw.state & PERF_HES_STOPPED)
8068 * All tracepoints are from kernel-space.
8070 if (event->attr.exclude_kernel)
8073 if (!perf_tp_filter_match(event, data))
8079 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8080 struct trace_event_call *call, u64 count,
8081 struct pt_regs *regs, struct hlist_head *head,
8082 struct task_struct *task)
8084 struct bpf_prog *prog = call->prog;
8087 *(struct pt_regs **)raw_data = regs;
8088 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
8089 perf_swevent_put_recursion_context(rctx);
8093 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8096 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8098 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8099 struct pt_regs *regs, struct hlist_head *head, int rctx,
8100 struct task_struct *task, struct perf_event *event)
8102 struct perf_sample_data data;
8104 struct perf_raw_record raw = {
8111 perf_sample_data_init(&data, 0, 0);
8114 perf_trace_buf_update(record, event_type);
8116 /* Use the given event instead of the hlist */
8118 if (perf_tp_event_match(event, &data, regs))
8119 perf_swevent_event(event, count, &data, regs);
8121 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8122 if (perf_tp_event_match(event, &data, regs))
8123 perf_swevent_event(event, count, &data, regs);
8128 * If we got specified a target task, also iterate its context and
8129 * deliver this event there too.
8131 if (task && task != current) {
8132 struct perf_event_context *ctx;
8133 struct trace_entry *entry = record;
8136 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8140 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8141 if (event->cpu != smp_processor_id())
8143 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8145 if (event->attr.config != entry->type)
8147 if (perf_tp_event_match(event, &data, regs))
8148 perf_swevent_event(event, count, &data, regs);
8154 perf_swevent_put_recursion_context(rctx);
8156 EXPORT_SYMBOL_GPL(perf_tp_event);
8158 static void tp_perf_event_destroy(struct perf_event *event)
8160 perf_trace_destroy(event);
8163 static int perf_tp_event_init(struct perf_event *event)
8167 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8171 * no branch sampling for tracepoint events
8173 if (has_branch_stack(event))
8176 err = perf_trace_init(event);
8180 event->destroy = tp_perf_event_destroy;
8185 static struct pmu perf_tracepoint = {
8186 .task_ctx_nr = perf_sw_context,
8188 .event_init = perf_tp_event_init,
8189 .add = perf_trace_add,
8190 .del = perf_trace_del,
8191 .start = perf_swevent_start,
8192 .stop = perf_swevent_stop,
8193 .read = perf_swevent_read,
8196 static inline void perf_tp_register(void)
8198 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8201 static void perf_event_free_filter(struct perf_event *event)
8203 ftrace_profile_free_filter(event);
8206 #ifdef CONFIG_BPF_SYSCALL
8207 static void bpf_overflow_handler(struct perf_event *event,
8208 struct perf_sample_data *data,
8209 struct pt_regs *regs)
8211 struct bpf_perf_event_data_kern ctx = {
8218 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8221 ret = BPF_PROG_RUN(event->prog, &ctx);
8224 __this_cpu_dec(bpf_prog_active);
8229 event->orig_overflow_handler(event, data, regs);
8232 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8234 struct bpf_prog *prog;
8236 if (event->overflow_handler_context)
8237 /* hw breakpoint or kernel counter */
8243 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8245 return PTR_ERR(prog);
8248 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8249 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8253 static void perf_event_free_bpf_handler(struct perf_event *event)
8255 struct bpf_prog *prog = event->prog;
8260 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8265 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8269 static void perf_event_free_bpf_handler(struct perf_event *event)
8274 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8276 bool is_kprobe, is_tracepoint, is_syscall_tp;
8277 struct bpf_prog *prog;
8279 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8280 return perf_event_set_bpf_handler(event, prog_fd);
8282 if (event->tp_event->prog)
8285 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8286 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8287 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8288 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8289 /* bpf programs can only be attached to u/kprobe or tracepoint */
8292 prog = bpf_prog_get(prog_fd);
8294 return PTR_ERR(prog);
8296 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8297 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8298 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8299 /* valid fd, but invalid bpf program type */
8304 if (is_tracepoint || is_syscall_tp) {
8305 int off = trace_event_get_offsets(event->tp_event);
8307 if (prog->aux->max_ctx_offset > off) {
8312 event->tp_event->prog = prog;
8313 event->tp_event->bpf_prog_owner = event;
8318 static void perf_event_free_bpf_prog(struct perf_event *event)
8320 struct bpf_prog *prog;
8322 perf_event_free_bpf_handler(event);
8324 if (!event->tp_event)
8327 prog = event->tp_event->prog;
8328 if (prog && event->tp_event->bpf_prog_owner == event) {
8329 event->tp_event->prog = NULL;
8336 static inline void perf_tp_register(void)
8340 static void perf_event_free_filter(struct perf_event *event)
8344 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8349 static void perf_event_free_bpf_prog(struct perf_event *event)
8352 #endif /* CONFIG_EVENT_TRACING */
8354 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8355 void perf_bp_event(struct perf_event *bp, void *data)
8357 struct perf_sample_data sample;
8358 struct pt_regs *regs = data;
8360 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8362 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8363 perf_swevent_event(bp, 1, &sample, regs);
8368 * Allocate a new address filter
8370 static struct perf_addr_filter *
8371 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8373 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8374 struct perf_addr_filter *filter;
8376 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8380 INIT_LIST_HEAD(&filter->entry);
8381 list_add_tail(&filter->entry, filters);
8386 static void free_filters_list(struct list_head *filters)
8388 struct perf_addr_filter *filter, *iter;
8390 list_for_each_entry_safe(filter, iter, filters, entry) {
8391 path_put(&filter->path);
8392 list_del(&filter->entry);
8398 * Free existing address filters and optionally install new ones
8400 static void perf_addr_filters_splice(struct perf_event *event,
8401 struct list_head *head)
8403 unsigned long flags;
8406 if (!has_addr_filter(event))
8409 /* don't bother with children, they don't have their own filters */
8413 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8415 list_splice_init(&event->addr_filters.list, &list);
8417 list_splice(head, &event->addr_filters.list);
8419 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8421 free_filters_list(&list);
8425 * Scan through mm's vmas and see if one of them matches the
8426 * @filter; if so, adjust filter's address range.
8427 * Called with mm::mmap_sem down for reading.
8429 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8430 struct mm_struct *mm)
8432 struct vm_area_struct *vma;
8434 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8435 struct file *file = vma->vm_file;
8436 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8437 unsigned long vma_size = vma->vm_end - vma->vm_start;
8442 if (!perf_addr_filter_match(filter, file, off, vma_size))
8445 return vma->vm_start;
8452 * Update event's address range filters based on the
8453 * task's existing mappings, if any.
8455 static void perf_event_addr_filters_apply(struct perf_event *event)
8457 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8458 struct task_struct *task = READ_ONCE(event->ctx->task);
8459 struct perf_addr_filter *filter;
8460 struct mm_struct *mm = NULL;
8461 unsigned int count = 0;
8462 unsigned long flags;
8465 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8466 * will stop on the parent's child_mutex that our caller is also holding
8468 if (task == TASK_TOMBSTONE)
8471 if (!ifh->nr_file_filters)
8474 mm = get_task_mm(task);
8478 down_read(&mm->mmap_sem);
8480 raw_spin_lock_irqsave(&ifh->lock, flags);
8481 list_for_each_entry(filter, &ifh->list, entry) {
8482 event->addr_filters_offs[count] = 0;
8485 * Adjust base offset if the filter is associated to a binary
8486 * that needs to be mapped:
8488 if (filter->path.dentry)
8489 event->addr_filters_offs[count] =
8490 perf_addr_filter_apply(filter, mm);
8495 event->addr_filters_gen++;
8496 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8498 up_read(&mm->mmap_sem);
8503 perf_event_stop(event, 1);
8507 * Address range filtering: limiting the data to certain
8508 * instruction address ranges. Filters are ioctl()ed to us from
8509 * userspace as ascii strings.
8511 * Filter string format:
8514 * where ACTION is one of the
8515 * * "filter": limit the trace to this region
8516 * * "start": start tracing from this address
8517 * * "stop": stop tracing at this address/region;
8519 * * for kernel addresses: <start address>[/<size>]
8520 * * for object files: <start address>[/<size>]@</path/to/object/file>
8522 * if <size> is not specified, the range is treated as a single address.
8536 IF_STATE_ACTION = 0,
8541 static const match_table_t if_tokens = {
8542 { IF_ACT_FILTER, "filter" },
8543 { IF_ACT_START, "start" },
8544 { IF_ACT_STOP, "stop" },
8545 { IF_SRC_FILE, "%u/%u@%s" },
8546 { IF_SRC_KERNEL, "%u/%u" },
8547 { IF_SRC_FILEADDR, "%u@%s" },
8548 { IF_SRC_KERNELADDR, "%u" },
8549 { IF_ACT_NONE, NULL },
8553 * Address filter string parser
8556 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8557 struct list_head *filters)
8559 struct perf_addr_filter *filter = NULL;
8560 char *start, *orig, *filename = NULL;
8561 substring_t args[MAX_OPT_ARGS];
8562 int state = IF_STATE_ACTION, token;
8563 unsigned int kernel = 0;
8566 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8570 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8576 /* filter definition begins */
8577 if (state == IF_STATE_ACTION) {
8578 filter = perf_addr_filter_new(event, filters);
8583 token = match_token(start, if_tokens, args);
8590 if (state != IF_STATE_ACTION)
8593 state = IF_STATE_SOURCE;
8596 case IF_SRC_KERNELADDR:
8600 case IF_SRC_FILEADDR:
8602 if (state != IF_STATE_SOURCE)
8605 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8609 ret = kstrtoul(args[0].from, 0, &filter->offset);
8613 if (filter->range) {
8615 ret = kstrtoul(args[1].from, 0, &filter->size);
8620 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8621 int fpos = filter->range ? 2 : 1;
8624 filename = match_strdup(&args[fpos]);
8631 state = IF_STATE_END;
8639 * Filter definition is fully parsed, validate and install it.
8640 * Make sure that it doesn't contradict itself or the event's
8643 if (state == IF_STATE_END) {
8645 if (kernel && event->attr.exclude_kernel)
8653 * For now, we only support file-based filters
8654 * in per-task events; doing so for CPU-wide
8655 * events requires additional context switching
8656 * trickery, since same object code will be
8657 * mapped at different virtual addresses in
8658 * different processes.
8661 if (!event->ctx->task)
8664 /* look up the path and grab its inode */
8665 ret = kern_path(filename, LOOKUP_FOLLOW,
8671 if (!filter->path.dentry ||
8672 !S_ISREG(d_inode(filter->path.dentry)
8676 event->addr_filters.nr_file_filters++;
8679 /* ready to consume more filters */
8682 state = IF_STATE_ACTION;
8688 if (state != IF_STATE_ACTION)
8698 free_filters_list(filters);
8705 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8711 * Since this is called in perf_ioctl() path, we're already holding
8714 lockdep_assert_held(&event->ctx->mutex);
8716 if (WARN_ON_ONCE(event->parent))
8719 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8721 goto fail_clear_files;
8723 ret = event->pmu->addr_filters_validate(&filters);
8725 goto fail_free_filters;
8727 /* remove existing filters, if any */
8728 perf_addr_filters_splice(event, &filters);
8730 /* install new filters */
8731 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8736 free_filters_list(&filters);
8739 event->addr_filters.nr_file_filters = 0;
8744 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8749 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8750 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8751 !has_addr_filter(event))
8754 filter_str = strndup_user(arg, PAGE_SIZE);
8755 if (IS_ERR(filter_str))
8756 return PTR_ERR(filter_str);
8758 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8759 event->attr.type == PERF_TYPE_TRACEPOINT)
8760 ret = ftrace_profile_set_filter(event, event->attr.config,
8762 else if (has_addr_filter(event))
8763 ret = perf_event_set_addr_filter(event, filter_str);
8770 * hrtimer based swevent callback
8773 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8775 enum hrtimer_restart ret = HRTIMER_RESTART;
8776 struct perf_sample_data data;
8777 struct pt_regs *regs;
8778 struct perf_event *event;
8781 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8783 if (event->state != PERF_EVENT_STATE_ACTIVE)
8784 return HRTIMER_NORESTART;
8786 event->pmu->read(event);
8788 perf_sample_data_init(&data, 0, event->hw.last_period);
8789 regs = get_irq_regs();
8791 if (regs && !perf_exclude_event(event, regs)) {
8792 if (!(event->attr.exclude_idle && is_idle_task(current)))
8793 if (__perf_event_overflow(event, 1, &data, regs))
8794 ret = HRTIMER_NORESTART;
8797 period = max_t(u64, 10000, event->hw.sample_period);
8798 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8803 static void perf_swevent_start_hrtimer(struct perf_event *event)
8805 struct hw_perf_event *hwc = &event->hw;
8808 if (!is_sampling_event(event))
8811 period = local64_read(&hwc->period_left);
8816 local64_set(&hwc->period_left, 0);
8818 period = max_t(u64, 10000, hwc->sample_period);
8820 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8821 HRTIMER_MODE_REL_PINNED);
8824 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8826 struct hw_perf_event *hwc = &event->hw;
8828 if (is_sampling_event(event)) {
8829 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8830 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8832 hrtimer_cancel(&hwc->hrtimer);
8836 static void perf_swevent_init_hrtimer(struct perf_event *event)
8838 struct hw_perf_event *hwc = &event->hw;
8840 if (!is_sampling_event(event))
8843 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8844 hwc->hrtimer.function = perf_swevent_hrtimer;
8847 * Since hrtimers have a fixed rate, we can do a static freq->period
8848 * mapping and avoid the whole period adjust feedback stuff.
8850 if (event->attr.freq) {
8851 long freq = event->attr.sample_freq;
8853 event->attr.sample_period = NSEC_PER_SEC / freq;
8854 hwc->sample_period = event->attr.sample_period;
8855 local64_set(&hwc->period_left, hwc->sample_period);
8856 hwc->last_period = hwc->sample_period;
8857 event->attr.freq = 0;
8862 * Software event: cpu wall time clock
8865 static void cpu_clock_event_update(struct perf_event *event)
8870 now = local_clock();
8871 prev = local64_xchg(&event->hw.prev_count, now);
8872 local64_add(now - prev, &event->count);
8875 static void cpu_clock_event_start(struct perf_event *event, int flags)
8877 local64_set(&event->hw.prev_count, local_clock());
8878 perf_swevent_start_hrtimer(event);
8881 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8883 perf_swevent_cancel_hrtimer(event);
8884 cpu_clock_event_update(event);
8887 static int cpu_clock_event_add(struct perf_event *event, int flags)
8889 if (flags & PERF_EF_START)
8890 cpu_clock_event_start(event, flags);
8891 perf_event_update_userpage(event);
8896 static void cpu_clock_event_del(struct perf_event *event, int flags)
8898 cpu_clock_event_stop(event, flags);
8901 static void cpu_clock_event_read(struct perf_event *event)
8903 cpu_clock_event_update(event);
8906 static int cpu_clock_event_init(struct perf_event *event)
8908 if (event->attr.type != PERF_TYPE_SOFTWARE)
8911 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8915 * no branch sampling for software events
8917 if (has_branch_stack(event))
8920 perf_swevent_init_hrtimer(event);
8925 static struct pmu perf_cpu_clock = {
8926 .task_ctx_nr = perf_sw_context,
8928 .capabilities = PERF_PMU_CAP_NO_NMI,
8930 .event_init = cpu_clock_event_init,
8931 .add = cpu_clock_event_add,
8932 .del = cpu_clock_event_del,
8933 .start = cpu_clock_event_start,
8934 .stop = cpu_clock_event_stop,
8935 .read = cpu_clock_event_read,
8939 * Software event: task time clock
8942 static void task_clock_event_update(struct perf_event *event, u64 now)
8947 prev = local64_xchg(&event->hw.prev_count, now);
8949 local64_add(delta, &event->count);
8952 static void task_clock_event_start(struct perf_event *event, int flags)
8954 local64_set(&event->hw.prev_count, event->ctx->time);
8955 perf_swevent_start_hrtimer(event);
8958 static void task_clock_event_stop(struct perf_event *event, int flags)
8960 perf_swevent_cancel_hrtimer(event);
8961 task_clock_event_update(event, event->ctx->time);
8964 static int task_clock_event_add(struct perf_event *event, int flags)
8966 if (flags & PERF_EF_START)
8967 task_clock_event_start(event, flags);
8968 perf_event_update_userpage(event);
8973 static void task_clock_event_del(struct perf_event *event, int flags)
8975 task_clock_event_stop(event, PERF_EF_UPDATE);
8978 static void task_clock_event_read(struct perf_event *event)
8980 u64 now = perf_clock();
8981 u64 delta = now - event->ctx->timestamp;
8982 u64 time = event->ctx->time + delta;
8984 task_clock_event_update(event, time);
8987 static int task_clock_event_init(struct perf_event *event)
8989 if (event->attr.type != PERF_TYPE_SOFTWARE)
8992 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8996 * no branch sampling for software events
8998 if (has_branch_stack(event))
9001 perf_swevent_init_hrtimer(event);
9006 static struct pmu perf_task_clock = {
9007 .task_ctx_nr = perf_sw_context,
9009 .capabilities = PERF_PMU_CAP_NO_NMI,
9011 .event_init = task_clock_event_init,
9012 .add = task_clock_event_add,
9013 .del = task_clock_event_del,
9014 .start = task_clock_event_start,
9015 .stop = task_clock_event_stop,
9016 .read = task_clock_event_read,
9019 static void perf_pmu_nop_void(struct pmu *pmu)
9023 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9027 static int perf_pmu_nop_int(struct pmu *pmu)
9032 static int perf_event_nop_int(struct perf_event *event, u64 value)
9037 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9039 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9041 __this_cpu_write(nop_txn_flags, flags);
9043 if (flags & ~PERF_PMU_TXN_ADD)
9046 perf_pmu_disable(pmu);
9049 static int perf_pmu_commit_txn(struct pmu *pmu)
9051 unsigned int flags = __this_cpu_read(nop_txn_flags);
9053 __this_cpu_write(nop_txn_flags, 0);
9055 if (flags & ~PERF_PMU_TXN_ADD)
9058 perf_pmu_enable(pmu);
9062 static void perf_pmu_cancel_txn(struct pmu *pmu)
9064 unsigned int flags = __this_cpu_read(nop_txn_flags);
9066 __this_cpu_write(nop_txn_flags, 0);
9068 if (flags & ~PERF_PMU_TXN_ADD)
9071 perf_pmu_enable(pmu);
9074 static int perf_event_idx_default(struct perf_event *event)
9080 * Ensures all contexts with the same task_ctx_nr have the same
9081 * pmu_cpu_context too.
9083 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9090 list_for_each_entry(pmu, &pmus, entry) {
9091 if (pmu->task_ctx_nr == ctxn)
9092 return pmu->pmu_cpu_context;
9098 static void free_pmu_context(struct pmu *pmu)
9101 * Static contexts such as perf_sw_context have a global lifetime
9102 * and may be shared between different PMUs. Avoid freeing them
9103 * when a single PMU is going away.
9105 if (pmu->task_ctx_nr > perf_invalid_context)
9108 free_percpu(pmu->pmu_cpu_context);
9112 * Let userspace know that this PMU supports address range filtering:
9114 static ssize_t nr_addr_filters_show(struct device *dev,
9115 struct device_attribute *attr,
9118 struct pmu *pmu = dev_get_drvdata(dev);
9120 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9122 DEVICE_ATTR_RO(nr_addr_filters);
9124 static struct idr pmu_idr;
9127 type_show(struct device *dev, struct device_attribute *attr, char *page)
9129 struct pmu *pmu = dev_get_drvdata(dev);
9131 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9133 static DEVICE_ATTR_RO(type);
9136 perf_event_mux_interval_ms_show(struct device *dev,
9137 struct device_attribute *attr,
9140 struct pmu *pmu = dev_get_drvdata(dev);
9142 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9145 static DEFINE_MUTEX(mux_interval_mutex);
9148 perf_event_mux_interval_ms_store(struct device *dev,
9149 struct device_attribute *attr,
9150 const char *buf, size_t count)
9152 struct pmu *pmu = dev_get_drvdata(dev);
9153 int timer, cpu, ret;
9155 ret = kstrtoint(buf, 0, &timer);
9162 /* same value, noting to do */
9163 if (timer == pmu->hrtimer_interval_ms)
9166 mutex_lock(&mux_interval_mutex);
9167 pmu->hrtimer_interval_ms = timer;
9169 /* update all cpuctx for this PMU */
9171 for_each_online_cpu(cpu) {
9172 struct perf_cpu_context *cpuctx;
9173 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9174 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9176 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpuctx);
9179 mutex_unlock(&mux_interval_mutex);
9183 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9185 static struct attribute *pmu_dev_attrs[] = {
9186 &dev_attr_type.attr,
9187 &dev_attr_perf_event_mux_interval_ms.attr,
9190 ATTRIBUTE_GROUPS(pmu_dev);
9192 static int pmu_bus_running;
9193 static struct bus_type pmu_bus = {
9194 .name = "event_source",
9195 .dev_groups = pmu_dev_groups,
9198 static void pmu_dev_release(struct device *dev)
9203 static int pmu_dev_alloc(struct pmu *pmu)
9207 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9211 pmu->dev->groups = pmu->attr_groups;
9212 device_initialize(pmu->dev);
9214 dev_set_drvdata(pmu->dev, pmu);
9215 pmu->dev->bus = &pmu_bus;
9216 pmu->dev->release = pmu_dev_release;
9218 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9222 ret = device_add(pmu->dev);
9226 /* For PMUs with address filters, throw in an extra attribute: */
9227 if (pmu->nr_addr_filters)
9228 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9237 device_del(pmu->dev);
9240 put_device(pmu->dev);
9244 static struct lock_class_key cpuctx_mutex;
9245 static struct lock_class_key cpuctx_lock;
9247 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9251 mutex_lock(&pmus_lock);
9253 pmu->pmu_disable_count = alloc_percpu(int);
9254 if (!pmu->pmu_disable_count)
9263 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9271 if (pmu_bus_running) {
9272 ret = pmu_dev_alloc(pmu);
9278 if (pmu->task_ctx_nr == perf_hw_context) {
9279 static int hw_context_taken = 0;
9282 * Other than systems with heterogeneous CPUs, it never makes
9283 * sense for two PMUs to share perf_hw_context. PMUs which are
9284 * uncore must use perf_invalid_context.
9286 if (WARN_ON_ONCE(hw_context_taken &&
9287 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9288 pmu->task_ctx_nr = perf_invalid_context;
9290 hw_context_taken = 1;
9293 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9294 if (pmu->pmu_cpu_context)
9295 goto got_cpu_context;
9298 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9299 if (!pmu->pmu_cpu_context)
9302 for_each_possible_cpu(cpu) {
9303 struct perf_cpu_context *cpuctx;
9305 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9306 __perf_event_init_context(&cpuctx->ctx);
9307 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9308 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9309 cpuctx->ctx.pmu = pmu;
9310 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9312 __perf_mux_hrtimer_init(cpuctx, cpu);
9316 if (!pmu->start_txn) {
9317 if (pmu->pmu_enable) {
9319 * If we have pmu_enable/pmu_disable calls, install
9320 * transaction stubs that use that to try and batch
9321 * hardware accesses.
9323 pmu->start_txn = perf_pmu_start_txn;
9324 pmu->commit_txn = perf_pmu_commit_txn;
9325 pmu->cancel_txn = perf_pmu_cancel_txn;
9327 pmu->start_txn = perf_pmu_nop_txn;
9328 pmu->commit_txn = perf_pmu_nop_int;
9329 pmu->cancel_txn = perf_pmu_nop_void;
9333 if (!pmu->pmu_enable) {
9334 pmu->pmu_enable = perf_pmu_nop_void;
9335 pmu->pmu_disable = perf_pmu_nop_void;
9338 if (!pmu->check_period)
9339 pmu->check_period = perf_event_nop_int;
9341 if (!pmu->event_idx)
9342 pmu->event_idx = perf_event_idx_default;
9344 list_add_rcu(&pmu->entry, &pmus);
9345 atomic_set(&pmu->exclusive_cnt, 0);
9348 mutex_unlock(&pmus_lock);
9353 device_del(pmu->dev);
9354 put_device(pmu->dev);
9357 if (pmu->type >= PERF_TYPE_MAX)
9358 idr_remove(&pmu_idr, pmu->type);
9361 free_percpu(pmu->pmu_disable_count);
9364 EXPORT_SYMBOL_GPL(perf_pmu_register);
9366 void perf_pmu_unregister(struct pmu *pmu)
9368 mutex_lock(&pmus_lock);
9369 list_del_rcu(&pmu->entry);
9372 * We dereference the pmu list under both SRCU and regular RCU, so
9373 * synchronize against both of those.
9375 synchronize_srcu(&pmus_srcu);
9378 free_percpu(pmu->pmu_disable_count);
9379 if (pmu->type >= PERF_TYPE_MAX)
9380 idr_remove(&pmu_idr, pmu->type);
9381 if (pmu_bus_running) {
9382 if (pmu->nr_addr_filters)
9383 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9384 device_del(pmu->dev);
9385 put_device(pmu->dev);
9387 free_pmu_context(pmu);
9388 mutex_unlock(&pmus_lock);
9390 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9392 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9394 struct perf_event_context *ctx = NULL;
9397 if (!try_module_get(pmu->module))
9400 if (event->group_leader != event) {
9402 * This ctx->mutex can nest when we're called through
9403 * inheritance. See the perf_event_ctx_lock_nested() comment.
9405 ctx = perf_event_ctx_lock_nested(event->group_leader,
9406 SINGLE_DEPTH_NESTING);
9411 ret = pmu->event_init(event);
9414 perf_event_ctx_unlock(event->group_leader, ctx);
9417 module_put(pmu->module);
9422 static struct pmu *perf_init_event(struct perf_event *event)
9428 idx = srcu_read_lock(&pmus_srcu);
9430 /* Try parent's PMU first: */
9431 if (event->parent && event->parent->pmu) {
9432 pmu = event->parent->pmu;
9433 ret = perf_try_init_event(pmu, event);
9439 pmu = idr_find(&pmu_idr, event->attr.type);
9442 ret = perf_try_init_event(pmu, event);
9448 list_for_each_entry_rcu(pmu, &pmus, entry) {
9449 ret = perf_try_init_event(pmu, event);
9453 if (ret != -ENOENT) {
9458 pmu = ERR_PTR(-ENOENT);
9460 srcu_read_unlock(&pmus_srcu, idx);
9465 static void attach_sb_event(struct perf_event *event)
9467 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9469 raw_spin_lock(&pel->lock);
9470 list_add_rcu(&event->sb_list, &pel->list);
9471 raw_spin_unlock(&pel->lock);
9475 * We keep a list of all !task (and therefore per-cpu) events
9476 * that need to receive side-band records.
9478 * This avoids having to scan all the various PMU per-cpu contexts
9481 static void account_pmu_sb_event(struct perf_event *event)
9483 if (is_sb_event(event))
9484 attach_sb_event(event);
9487 static void account_event_cpu(struct perf_event *event, int cpu)
9492 if (is_cgroup_event(event))
9493 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9496 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9497 static void account_freq_event_nohz(void)
9499 #ifdef CONFIG_NO_HZ_FULL
9500 /* Lock so we don't race with concurrent unaccount */
9501 spin_lock(&nr_freq_lock);
9502 if (atomic_inc_return(&nr_freq_events) == 1)
9503 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9504 spin_unlock(&nr_freq_lock);
9508 static void account_freq_event(void)
9510 if (tick_nohz_full_enabled())
9511 account_freq_event_nohz();
9513 atomic_inc(&nr_freq_events);
9517 static void account_event(struct perf_event *event)
9524 if (event->attach_state & PERF_ATTACH_TASK)
9526 if (event->attr.mmap || event->attr.mmap_data)
9527 atomic_inc(&nr_mmap_events);
9528 if (event->attr.comm)
9529 atomic_inc(&nr_comm_events);
9530 if (event->attr.namespaces)
9531 atomic_inc(&nr_namespaces_events);
9532 if (event->attr.task)
9533 atomic_inc(&nr_task_events);
9534 if (event->attr.freq)
9535 account_freq_event();
9536 if (event->attr.context_switch) {
9537 atomic_inc(&nr_switch_events);
9540 if (has_branch_stack(event))
9542 if (is_cgroup_event(event))
9546 if (atomic_inc_not_zero(&perf_sched_count))
9549 mutex_lock(&perf_sched_mutex);
9550 if (!atomic_read(&perf_sched_count)) {
9551 static_branch_enable(&perf_sched_events);
9553 * Guarantee that all CPUs observe they key change and
9554 * call the perf scheduling hooks before proceeding to
9555 * install events that need them.
9557 synchronize_sched();
9560 * Now that we have waited for the sync_sched(), allow further
9561 * increments to by-pass the mutex.
9563 atomic_inc(&perf_sched_count);
9564 mutex_unlock(&perf_sched_mutex);
9568 account_event_cpu(event, event->cpu);
9570 account_pmu_sb_event(event);
9574 * Allocate and initialize a event structure
9576 static struct perf_event *
9577 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9578 struct task_struct *task,
9579 struct perf_event *group_leader,
9580 struct perf_event *parent_event,
9581 perf_overflow_handler_t overflow_handler,
9582 void *context, int cgroup_fd)
9585 struct perf_event *event;
9586 struct hw_perf_event *hwc;
9589 if ((unsigned)cpu >= nr_cpu_ids) {
9590 if (!task || cpu != -1)
9591 return ERR_PTR(-EINVAL);
9594 event = kzalloc(sizeof(*event), GFP_KERNEL);
9596 return ERR_PTR(-ENOMEM);
9599 * Single events are their own group leaders, with an
9600 * empty sibling list:
9603 group_leader = event;
9605 mutex_init(&event->child_mutex);
9606 INIT_LIST_HEAD(&event->child_list);
9608 INIT_LIST_HEAD(&event->group_entry);
9609 INIT_LIST_HEAD(&event->event_entry);
9610 INIT_LIST_HEAD(&event->sibling_list);
9611 INIT_LIST_HEAD(&event->rb_entry);
9612 INIT_LIST_HEAD(&event->active_entry);
9613 INIT_LIST_HEAD(&event->addr_filters.list);
9614 INIT_HLIST_NODE(&event->hlist_entry);
9617 init_waitqueue_head(&event->waitq);
9618 init_irq_work(&event->pending, perf_pending_event);
9620 mutex_init(&event->mmap_mutex);
9621 raw_spin_lock_init(&event->addr_filters.lock);
9623 atomic_long_set(&event->refcount, 1);
9625 event->attr = *attr;
9626 event->group_leader = group_leader;
9630 event->parent = parent_event;
9632 event->ns = get_pid_ns(task_active_pid_ns(current));
9633 event->id = atomic64_inc_return(&perf_event_id);
9635 event->state = PERF_EVENT_STATE_INACTIVE;
9638 event->attach_state = PERF_ATTACH_TASK;
9640 * XXX pmu::event_init needs to know what task to account to
9641 * and we cannot use the ctx information because we need the
9642 * pmu before we get a ctx.
9644 get_task_struct(task);
9645 event->hw.target = task;
9648 event->clock = &local_clock;
9650 event->clock = parent_event->clock;
9652 if (!overflow_handler && parent_event) {
9653 overflow_handler = parent_event->overflow_handler;
9654 context = parent_event->overflow_handler_context;
9655 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9656 if (overflow_handler == bpf_overflow_handler) {
9657 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9660 err = PTR_ERR(prog);
9664 event->orig_overflow_handler =
9665 parent_event->orig_overflow_handler;
9670 if (overflow_handler) {
9671 event->overflow_handler = overflow_handler;
9672 event->overflow_handler_context = context;
9673 } else if (is_write_backward(event)){
9674 event->overflow_handler = perf_event_output_backward;
9675 event->overflow_handler_context = NULL;
9677 event->overflow_handler = perf_event_output_forward;
9678 event->overflow_handler_context = NULL;
9681 perf_event__state_init(event);
9686 hwc->sample_period = attr->sample_period;
9687 if (attr->freq && attr->sample_freq)
9688 hwc->sample_period = 1;
9689 hwc->last_period = hwc->sample_period;
9691 local64_set(&hwc->period_left, hwc->sample_period);
9694 * We currently do not support PERF_SAMPLE_READ on inherited events.
9695 * See perf_output_read().
9697 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9700 if (!has_branch_stack(event))
9701 event->attr.branch_sample_type = 0;
9703 if (cgroup_fd != -1) {
9704 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9709 pmu = perf_init_event(event);
9715 err = exclusive_event_init(event);
9719 if (has_addr_filter(event)) {
9720 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9721 sizeof(unsigned long),
9723 if (!event->addr_filters_offs) {
9728 /* force hw sync on the address filters */
9729 event->addr_filters_gen = 1;
9732 if (!event->parent) {
9733 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9734 err = get_callchain_buffers(attr->sample_max_stack);
9736 goto err_addr_filters;
9740 /* symmetric to unaccount_event() in _free_event() */
9741 account_event(event);
9746 kfree(event->addr_filters_offs);
9749 exclusive_event_destroy(event);
9753 event->destroy(event);
9754 module_put(pmu->module);
9756 if (is_cgroup_event(event))
9757 perf_detach_cgroup(event);
9759 put_pid_ns(event->ns);
9760 if (event->hw.target)
9761 put_task_struct(event->hw.target);
9764 return ERR_PTR(err);
9767 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9768 struct perf_event_attr *attr)
9773 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9777 * zero the full structure, so that a short copy will be nice.
9779 memset(attr, 0, sizeof(*attr));
9781 ret = get_user(size, &uattr->size);
9785 if (size > PAGE_SIZE) /* silly large */
9788 if (!size) /* abi compat */
9789 size = PERF_ATTR_SIZE_VER0;
9791 if (size < PERF_ATTR_SIZE_VER0)
9795 * If we're handed a bigger struct than we know of,
9796 * ensure all the unknown bits are 0 - i.e. new
9797 * user-space does not rely on any kernel feature
9798 * extensions we dont know about yet.
9800 if (size > sizeof(*attr)) {
9801 unsigned char __user *addr;
9802 unsigned char __user *end;
9805 addr = (void __user *)uattr + sizeof(*attr);
9806 end = (void __user *)uattr + size;
9808 for (; addr < end; addr++) {
9809 ret = get_user(val, addr);
9815 size = sizeof(*attr);
9818 ret = copy_from_user(attr, uattr, size);
9824 if (attr->__reserved_1)
9827 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9830 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9833 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9834 u64 mask = attr->branch_sample_type;
9836 /* only using defined bits */
9837 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9840 /* at least one branch bit must be set */
9841 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9844 /* propagate priv level, when not set for branch */
9845 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9847 /* exclude_kernel checked on syscall entry */
9848 if (!attr->exclude_kernel)
9849 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9851 if (!attr->exclude_user)
9852 mask |= PERF_SAMPLE_BRANCH_USER;
9854 if (!attr->exclude_hv)
9855 mask |= PERF_SAMPLE_BRANCH_HV;
9857 * adjust user setting (for HW filter setup)
9859 attr->branch_sample_type = mask;
9861 /* privileged levels capture (kernel, hv): check permissions */
9862 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9863 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9867 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9868 ret = perf_reg_validate(attr->sample_regs_user);
9873 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9874 if (!arch_perf_have_user_stack_dump())
9878 * We have __u32 type for the size, but so far
9879 * we can only use __u16 as maximum due to the
9880 * __u16 sample size limit.
9882 if (attr->sample_stack_user >= USHRT_MAX)
9884 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9888 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9889 ret = perf_reg_validate(attr->sample_regs_intr);
9894 put_user(sizeof(*attr), &uattr->size);
9899 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9905 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9909 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9911 struct ring_buffer *rb = NULL;
9914 if (!output_event) {
9915 mutex_lock(&event->mmap_mutex);
9919 /* don't allow circular references */
9920 if (event == output_event)
9924 * Don't allow cross-cpu buffers
9926 if (output_event->cpu != event->cpu)
9930 * If its not a per-cpu rb, it must be the same task.
9932 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
9936 * Mixing clocks in the same buffer is trouble you don't need.
9938 if (output_event->clock != event->clock)
9942 * Either writing ring buffer from beginning or from end.
9943 * Mixing is not allowed.
9945 if (is_write_backward(output_event) != is_write_backward(event))
9949 * If both events generate aux data, they must be on the same PMU
9951 if (has_aux(event) && has_aux(output_event) &&
9952 event->pmu != output_event->pmu)
9956 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
9957 * output_event is already on rb->event_list, and the list iteration
9958 * restarts after every removal, it is guaranteed this new event is
9959 * observed *OR* if output_event is already removed, it's guaranteed we
9960 * observe !rb->mmap_count.
9962 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
9964 /* Can't redirect output if we've got an active mmap() */
9965 if (atomic_read(&event->mmap_count))
9969 /* get the rb we want to redirect to */
9970 rb = ring_buffer_get(output_event);
9974 /* did we race against perf_mmap_close() */
9975 if (!atomic_read(&rb->mmap_count)) {
9976 ring_buffer_put(rb);
9981 ring_buffer_attach(event, rb);
9985 mutex_unlock(&event->mmap_mutex);
9987 mutex_unlock(&output_event->mmap_mutex);
9993 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9995 bool nmi_safe = false;
9998 case CLOCK_MONOTONIC:
9999 event->clock = &ktime_get_mono_fast_ns;
10003 case CLOCK_MONOTONIC_RAW:
10004 event->clock = &ktime_get_raw_fast_ns;
10008 case CLOCK_REALTIME:
10009 event->clock = &ktime_get_real_ns;
10012 case CLOCK_BOOTTIME:
10013 event->clock = &ktime_get_boot_ns;
10017 event->clock = &ktime_get_tai_ns;
10024 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10031 * Variation on perf_event_ctx_lock_nested(), except we take two context
10034 static struct perf_event_context *
10035 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10036 struct perf_event_context *ctx)
10038 struct perf_event_context *gctx;
10042 gctx = READ_ONCE(group_leader->ctx);
10043 if (!atomic_inc_not_zero(&gctx->refcount)) {
10049 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10051 if (group_leader->ctx != gctx) {
10052 mutex_unlock(&ctx->mutex);
10053 mutex_unlock(&gctx->mutex);
10062 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10064 * @attr_uptr: event_id type attributes for monitoring/sampling
10067 * @group_fd: group leader event fd
10069 SYSCALL_DEFINE5(perf_event_open,
10070 struct perf_event_attr __user *, attr_uptr,
10071 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10073 struct perf_event *group_leader = NULL, *output_event = NULL;
10074 struct perf_event *event, *sibling;
10075 struct perf_event_attr attr;
10076 struct perf_event_context *ctx, *gctx;
10077 struct file *event_file = NULL;
10078 struct fd group = {NULL, 0};
10079 struct task_struct *task = NULL;
10082 int move_group = 0;
10084 int f_flags = O_RDWR;
10085 int cgroup_fd = -1;
10087 /* for future expandability... */
10088 if (flags & ~PERF_FLAG_ALL)
10091 err = perf_copy_attr(attr_uptr, &attr);
10095 if (!attr.exclude_kernel) {
10096 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10100 if (attr.namespaces) {
10101 if (!capable(CAP_SYS_ADMIN))
10106 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10109 if (attr.sample_period & (1ULL << 63))
10113 /* Only privileged users can get physical addresses */
10114 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10115 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10118 if (!attr.sample_max_stack)
10119 attr.sample_max_stack = sysctl_perf_event_max_stack;
10122 * In cgroup mode, the pid argument is used to pass the fd
10123 * opened to the cgroup directory in cgroupfs. The cpu argument
10124 * designates the cpu on which to monitor threads from that
10127 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10130 if (flags & PERF_FLAG_FD_CLOEXEC)
10131 f_flags |= O_CLOEXEC;
10133 event_fd = get_unused_fd_flags(f_flags);
10137 if (group_fd != -1) {
10138 err = perf_fget_light(group_fd, &group);
10141 group_leader = group.file->private_data;
10142 if (flags & PERF_FLAG_FD_OUTPUT)
10143 output_event = group_leader;
10144 if (flags & PERF_FLAG_FD_NO_GROUP)
10145 group_leader = NULL;
10148 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10149 task = find_lively_task_by_vpid(pid);
10150 if (IS_ERR(task)) {
10151 err = PTR_ERR(task);
10156 if (task && group_leader &&
10157 group_leader->attr.inherit != attr.inherit) {
10163 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10168 * Reuse ptrace permission checks for now.
10170 * We must hold cred_guard_mutex across this and any potential
10171 * perf_install_in_context() call for this new event to
10172 * serialize against exec() altering our credentials (and the
10173 * perf_event_exit_task() that could imply).
10176 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10180 if (flags & PERF_FLAG_PID_CGROUP)
10183 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10184 NULL, NULL, cgroup_fd);
10185 if (IS_ERR(event)) {
10186 err = PTR_ERR(event);
10190 if (is_sampling_event(event)) {
10191 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10198 * Special case software events and allow them to be part of
10199 * any hardware group.
10203 if (attr.use_clockid) {
10204 err = perf_event_set_clock(event, attr.clockid);
10209 if (pmu->task_ctx_nr == perf_sw_context)
10210 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10212 if (group_leader &&
10213 (is_software_event(event) != is_software_event(group_leader))) {
10214 if (is_software_event(event)) {
10216 * If event and group_leader are not both a software
10217 * event, and event is, then group leader is not.
10219 * Allow the addition of software events to !software
10220 * groups, this is safe because software events never
10221 * fail to schedule.
10223 pmu = group_leader->pmu;
10224 } else if (is_software_event(group_leader) &&
10225 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10227 * In case the group is a pure software group, and we
10228 * try to add a hardware event, move the whole group to
10229 * the hardware context.
10236 * Get the target context (task or percpu):
10238 ctx = find_get_context(pmu, task, event);
10240 err = PTR_ERR(ctx);
10244 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10250 * Look up the group leader (we will attach this event to it):
10252 if (group_leader) {
10256 * Do not allow a recursive hierarchy (this new sibling
10257 * becoming part of another group-sibling):
10259 if (group_leader->group_leader != group_leader)
10262 /* All events in a group should have the same clock */
10263 if (group_leader->clock != event->clock)
10267 * Make sure we're both events for the same CPU;
10268 * grouping events for different CPUs is broken; since
10269 * you can never concurrently schedule them anyhow.
10271 if (group_leader->cpu != event->cpu)
10275 * Make sure we're both on the same task, or both
10278 if (group_leader->ctx->task != ctx->task)
10282 * Do not allow to attach to a group in a different task
10283 * or CPU context. If we're moving SW events, we'll fix
10284 * this up later, so allow that.
10286 * Racy, not holding group_leader->ctx->mutex, see comment with
10287 * perf_event_ctx_lock().
10289 if (!move_group && group_leader->ctx != ctx)
10293 * Only a group leader can be exclusive or pinned
10295 if (attr.exclusive || attr.pinned)
10299 if (output_event) {
10300 err = perf_event_set_output(event, output_event);
10305 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10307 if (IS_ERR(event_file)) {
10308 err = PTR_ERR(event_file);
10314 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10316 if (gctx->task == TASK_TOMBSTONE) {
10322 * Check if we raced against another sys_perf_event_open() call
10323 * moving the software group underneath us.
10325 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10327 * If someone moved the group out from under us, check
10328 * if this new event wound up on the same ctx, if so
10329 * its the regular !move_group case, otherwise fail.
10335 perf_event_ctx_unlock(group_leader, gctx);
10337 goto not_move_group;
10341 mutex_lock(&ctx->mutex);
10344 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
10345 * see the group_leader && !move_group test earlier.
10347 if (group_leader && group_leader->ctx != ctx) {
10354 if (ctx->task == TASK_TOMBSTONE) {
10359 if (!perf_event_validate_size(event)) {
10366 * Check if the @cpu we're creating an event for is online.
10368 * We use the perf_cpu_context::ctx::mutex to serialize against
10369 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10371 struct perf_cpu_context *cpuctx =
10372 container_of(ctx, struct perf_cpu_context, ctx);
10374 if (!cpuctx->online) {
10382 * Must be under the same ctx::mutex as perf_install_in_context(),
10383 * because we need to serialize with concurrent event creation.
10385 if (!exclusive_event_installable(event, ctx)) {
10386 /* exclusive and group stuff are assumed mutually exclusive */
10387 WARN_ON_ONCE(move_group);
10393 WARN_ON_ONCE(ctx->parent_ctx);
10396 * This is the point on no return; we cannot fail hereafter. This is
10397 * where we start modifying current state.
10402 * See perf_event_ctx_lock() for comments on the details
10403 * of swizzling perf_event::ctx.
10405 perf_remove_from_context(group_leader, 0);
10408 list_for_each_entry(sibling, &group_leader->sibling_list,
10410 perf_remove_from_context(sibling, 0);
10415 * Wait for everybody to stop referencing the events through
10416 * the old lists, before installing it on new lists.
10421 * Install the group siblings before the group leader.
10423 * Because a group leader will try and install the entire group
10424 * (through the sibling list, which is still in-tact), we can
10425 * end up with siblings installed in the wrong context.
10427 * By installing siblings first we NO-OP because they're not
10428 * reachable through the group lists.
10430 list_for_each_entry(sibling, &group_leader->sibling_list,
10432 perf_event__state_init(sibling);
10433 perf_install_in_context(ctx, sibling, sibling->cpu);
10438 * Removing from the context ends up with disabled
10439 * event. What we want here is event in the initial
10440 * startup state, ready to be add into new context.
10442 perf_event__state_init(group_leader);
10443 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10448 * Precalculate sample_data sizes; do while holding ctx::mutex such
10449 * that we're serialized against further additions and before
10450 * perf_install_in_context() which is the point the event is active and
10451 * can use these values.
10453 perf_event__header_size(event);
10454 perf_event__id_header_size(event);
10456 event->owner = current;
10458 perf_install_in_context(ctx, event, event->cpu);
10459 perf_unpin_context(ctx);
10462 perf_event_ctx_unlock(group_leader, gctx);
10463 mutex_unlock(&ctx->mutex);
10466 mutex_unlock(&task->signal->cred_guard_mutex);
10467 put_task_struct(task);
10470 mutex_lock(¤t->perf_event_mutex);
10471 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10472 mutex_unlock(¤t->perf_event_mutex);
10475 * Drop the reference on the group_event after placing the
10476 * new event on the sibling_list. This ensures destruction
10477 * of the group leader will find the pointer to itself in
10478 * perf_group_detach().
10481 fd_install(event_fd, event_file);
10486 perf_event_ctx_unlock(group_leader, gctx);
10487 mutex_unlock(&ctx->mutex);
10491 perf_unpin_context(ctx);
10495 * If event_file is set, the fput() above will have called ->release()
10496 * and that will take care of freeing the event.
10502 mutex_unlock(&task->signal->cred_guard_mutex);
10505 put_task_struct(task);
10509 put_unused_fd(event_fd);
10514 * perf_event_create_kernel_counter
10516 * @attr: attributes of the counter to create
10517 * @cpu: cpu in which the counter is bound
10518 * @task: task to profile (NULL for percpu)
10520 struct perf_event *
10521 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10522 struct task_struct *task,
10523 perf_overflow_handler_t overflow_handler,
10526 struct perf_event_context *ctx;
10527 struct perf_event *event;
10531 * Get the target context (task or percpu):
10534 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10535 overflow_handler, context, -1);
10536 if (IS_ERR(event)) {
10537 err = PTR_ERR(event);
10541 /* Mark owner so we could distinguish it from user events. */
10542 event->owner = TASK_TOMBSTONE;
10544 ctx = find_get_context(event->pmu, task, event);
10546 err = PTR_ERR(ctx);
10550 WARN_ON_ONCE(ctx->parent_ctx);
10551 mutex_lock(&ctx->mutex);
10552 if (ctx->task == TASK_TOMBSTONE) {
10559 * Check if the @cpu we're creating an event for is online.
10561 * We use the perf_cpu_context::ctx::mutex to serialize against
10562 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10564 struct perf_cpu_context *cpuctx =
10565 container_of(ctx, struct perf_cpu_context, ctx);
10566 if (!cpuctx->online) {
10572 if (!exclusive_event_installable(event, ctx)) {
10577 perf_install_in_context(ctx, event, event->cpu);
10578 perf_unpin_context(ctx);
10579 mutex_unlock(&ctx->mutex);
10584 mutex_unlock(&ctx->mutex);
10585 perf_unpin_context(ctx);
10590 return ERR_PTR(err);
10592 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10594 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10596 struct perf_event_context *src_ctx;
10597 struct perf_event_context *dst_ctx;
10598 struct perf_event *event, *tmp;
10601 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10602 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10605 * See perf_event_ctx_lock() for comments on the details
10606 * of swizzling perf_event::ctx.
10608 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10609 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10611 perf_remove_from_context(event, 0);
10612 unaccount_event_cpu(event, src_cpu);
10614 list_add(&event->migrate_entry, &events);
10618 * Wait for the events to quiesce before re-instating them.
10623 * Re-instate events in 2 passes.
10625 * Skip over group leaders and only install siblings on this first
10626 * pass, siblings will not get enabled without a leader, however a
10627 * leader will enable its siblings, even if those are still on the old
10630 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10631 if (event->group_leader == event)
10634 list_del(&event->migrate_entry);
10635 if (event->state >= PERF_EVENT_STATE_OFF)
10636 event->state = PERF_EVENT_STATE_INACTIVE;
10637 account_event_cpu(event, dst_cpu);
10638 perf_install_in_context(dst_ctx, event, dst_cpu);
10643 * Once all the siblings are setup properly, install the group leaders
10646 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10647 list_del(&event->migrate_entry);
10648 if (event->state >= PERF_EVENT_STATE_OFF)
10649 event->state = PERF_EVENT_STATE_INACTIVE;
10650 account_event_cpu(event, dst_cpu);
10651 perf_install_in_context(dst_ctx, event, dst_cpu);
10654 mutex_unlock(&dst_ctx->mutex);
10655 mutex_unlock(&src_ctx->mutex);
10657 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10659 static void sync_child_event(struct perf_event *child_event,
10660 struct task_struct *child)
10662 struct perf_event *parent_event = child_event->parent;
10665 if (child_event->attr.inherit_stat)
10666 perf_event_read_event(child_event, child);
10668 child_val = perf_event_count(child_event);
10671 * Add back the child's count to the parent's count:
10673 atomic64_add(child_val, &parent_event->child_count);
10674 atomic64_add(child_event->total_time_enabled,
10675 &parent_event->child_total_time_enabled);
10676 atomic64_add(child_event->total_time_running,
10677 &parent_event->child_total_time_running);
10681 perf_event_exit_event(struct perf_event *child_event,
10682 struct perf_event_context *child_ctx,
10683 struct task_struct *child)
10685 struct perf_event *parent_event = child_event->parent;
10688 * Do not destroy the 'original' grouping; because of the context
10689 * switch optimization the original events could've ended up in a
10690 * random child task.
10692 * If we were to destroy the original group, all group related
10693 * operations would cease to function properly after this random
10696 * Do destroy all inherited groups, we don't care about those
10697 * and being thorough is better.
10699 raw_spin_lock_irq(&child_ctx->lock);
10700 WARN_ON_ONCE(child_ctx->is_active);
10703 perf_group_detach(child_event);
10704 list_del_event(child_event, child_ctx);
10705 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10706 raw_spin_unlock_irq(&child_ctx->lock);
10709 * Parent events are governed by their filedesc, retain them.
10711 if (!parent_event) {
10712 perf_event_wakeup(child_event);
10716 * Child events can be cleaned up.
10719 sync_child_event(child_event, child);
10722 * Remove this event from the parent's list
10724 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10725 mutex_lock(&parent_event->child_mutex);
10726 list_del_init(&child_event->child_list);
10727 mutex_unlock(&parent_event->child_mutex);
10730 * Kick perf_poll() for is_event_hup().
10732 perf_event_wakeup(parent_event);
10733 free_event(child_event);
10734 put_event(parent_event);
10737 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10739 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10740 struct perf_event *child_event, *next;
10742 WARN_ON_ONCE(child != current);
10744 child_ctx = perf_pin_task_context(child, ctxn);
10749 * In order to reduce the amount of tricky in ctx tear-down, we hold
10750 * ctx::mutex over the entire thing. This serializes against almost
10751 * everything that wants to access the ctx.
10753 * The exception is sys_perf_event_open() /
10754 * perf_event_create_kernel_count() which does find_get_context()
10755 * without ctx::mutex (it cannot because of the move_group double mutex
10756 * lock thing). See the comments in perf_install_in_context().
10758 mutex_lock(&child_ctx->mutex);
10761 * In a single ctx::lock section, de-schedule the events and detach the
10762 * context from the task such that we cannot ever get it scheduled back
10765 raw_spin_lock_irq(&child_ctx->lock);
10766 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10769 * Now that the context is inactive, destroy the task <-> ctx relation
10770 * and mark the context dead.
10772 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10773 put_ctx(child_ctx); /* cannot be last */
10774 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10775 put_task_struct(current); /* cannot be last */
10777 clone_ctx = unclone_ctx(child_ctx);
10778 raw_spin_unlock_irq(&child_ctx->lock);
10781 put_ctx(clone_ctx);
10784 * Report the task dead after unscheduling the events so that we
10785 * won't get any samples after PERF_RECORD_EXIT. We can however still
10786 * get a few PERF_RECORD_READ events.
10788 perf_event_task(child, child_ctx, 0);
10790 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10791 perf_event_exit_event(child_event, child_ctx, child);
10793 mutex_unlock(&child_ctx->mutex);
10795 put_ctx(child_ctx);
10799 * When a child task exits, feed back event values to parent events.
10801 * Can be called with cred_guard_mutex held when called from
10802 * install_exec_creds().
10804 void perf_event_exit_task(struct task_struct *child)
10806 struct perf_event *event, *tmp;
10809 mutex_lock(&child->perf_event_mutex);
10810 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10812 list_del_init(&event->owner_entry);
10815 * Ensure the list deletion is visible before we clear
10816 * the owner, closes a race against perf_release() where
10817 * we need to serialize on the owner->perf_event_mutex.
10819 smp_store_release(&event->owner, NULL);
10821 mutex_unlock(&child->perf_event_mutex);
10823 for_each_task_context_nr(ctxn)
10824 perf_event_exit_task_context(child, ctxn);
10827 * The perf_event_exit_task_context calls perf_event_task
10828 * with child's task_ctx, which generates EXIT events for
10829 * child contexts and sets child->perf_event_ctxp[] to NULL.
10830 * At this point we need to send EXIT events to cpu contexts.
10832 perf_event_task(child, NULL, 0);
10835 static void perf_free_event(struct perf_event *event,
10836 struct perf_event_context *ctx)
10838 struct perf_event *parent = event->parent;
10840 if (WARN_ON_ONCE(!parent))
10843 mutex_lock(&parent->child_mutex);
10844 list_del_init(&event->child_list);
10845 mutex_unlock(&parent->child_mutex);
10849 raw_spin_lock_irq(&ctx->lock);
10850 perf_group_detach(event);
10851 list_del_event(event, ctx);
10852 raw_spin_unlock_irq(&ctx->lock);
10857 * Free an unexposed, unused context as created by inheritance by
10858 * perf_event_init_task below, used by fork() in case of fail.
10860 * Not all locks are strictly required, but take them anyway to be nice and
10861 * help out with the lockdep assertions.
10863 void perf_event_free_task(struct task_struct *task)
10865 struct perf_event_context *ctx;
10866 struct perf_event *event, *tmp;
10869 for_each_task_context_nr(ctxn) {
10870 ctx = task->perf_event_ctxp[ctxn];
10874 mutex_lock(&ctx->mutex);
10875 raw_spin_lock_irq(&ctx->lock);
10877 * Destroy the task <-> ctx relation and mark the context dead.
10879 * This is important because even though the task hasn't been
10880 * exposed yet the context has been (through child_list).
10882 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10883 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10884 put_task_struct(task); /* cannot be last */
10885 raw_spin_unlock_irq(&ctx->lock);
10887 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10888 perf_free_event(event, ctx);
10890 mutex_unlock(&ctx->mutex);
10895 void perf_event_delayed_put(struct task_struct *task)
10899 for_each_task_context_nr(ctxn)
10900 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10903 struct file *perf_event_get(unsigned int fd)
10907 file = fget_raw(fd);
10909 return ERR_PTR(-EBADF);
10911 if (file->f_op != &perf_fops) {
10913 return ERR_PTR(-EBADF);
10919 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10922 return ERR_PTR(-EINVAL);
10924 return &event->attr;
10928 * Inherit a event from parent task to child task.
10931 * - valid pointer on success
10932 * - NULL for orphaned events
10933 * - IS_ERR() on error
10935 static struct perf_event *
10936 inherit_event(struct perf_event *parent_event,
10937 struct task_struct *parent,
10938 struct perf_event_context *parent_ctx,
10939 struct task_struct *child,
10940 struct perf_event *group_leader,
10941 struct perf_event_context *child_ctx)
10943 enum perf_event_active_state parent_state = parent_event->state;
10944 struct perf_event *child_event;
10945 unsigned long flags;
10948 * Instead of creating recursive hierarchies of events,
10949 * we link inherited events back to the original parent,
10950 * which has a filp for sure, which we use as the reference
10953 if (parent_event->parent)
10954 parent_event = parent_event->parent;
10956 child_event = perf_event_alloc(&parent_event->attr,
10959 group_leader, parent_event,
10961 if (IS_ERR(child_event))
10962 return child_event;
10965 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10966 * must be under the same lock in order to serialize against
10967 * perf_event_release_kernel(), such that either we must observe
10968 * is_orphaned_event() or they will observe us on the child_list.
10970 mutex_lock(&parent_event->child_mutex);
10971 if (is_orphaned_event(parent_event) ||
10972 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10973 mutex_unlock(&parent_event->child_mutex);
10974 free_event(child_event);
10978 get_ctx(child_ctx);
10981 * Make the child state follow the state of the parent event,
10982 * not its attr.disabled bit. We hold the parent's mutex,
10983 * so we won't race with perf_event_{en, dis}able_family.
10985 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10986 child_event->state = PERF_EVENT_STATE_INACTIVE;
10988 child_event->state = PERF_EVENT_STATE_OFF;
10990 if (parent_event->attr.freq) {
10991 u64 sample_period = parent_event->hw.sample_period;
10992 struct hw_perf_event *hwc = &child_event->hw;
10994 hwc->sample_period = sample_period;
10995 hwc->last_period = sample_period;
10997 local64_set(&hwc->period_left, sample_period);
11000 child_event->ctx = child_ctx;
11001 child_event->overflow_handler = parent_event->overflow_handler;
11002 child_event->overflow_handler_context
11003 = parent_event->overflow_handler_context;
11006 * Precalculate sample_data sizes
11008 perf_event__header_size(child_event);
11009 perf_event__id_header_size(child_event);
11012 * Link it up in the child's context:
11014 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11015 add_event_to_ctx(child_event, child_ctx);
11016 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11019 * Link this into the parent event's child list
11021 list_add_tail(&child_event->child_list, &parent_event->child_list);
11022 mutex_unlock(&parent_event->child_mutex);
11024 return child_event;
11028 * Inherits an event group.
11030 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11031 * This matches with perf_event_release_kernel() removing all child events.
11037 static int inherit_group(struct perf_event *parent_event,
11038 struct task_struct *parent,
11039 struct perf_event_context *parent_ctx,
11040 struct task_struct *child,
11041 struct perf_event_context *child_ctx)
11043 struct perf_event *leader;
11044 struct perf_event *sub;
11045 struct perf_event *child_ctr;
11047 leader = inherit_event(parent_event, parent, parent_ctx,
11048 child, NULL, child_ctx);
11049 if (IS_ERR(leader))
11050 return PTR_ERR(leader);
11052 * @leader can be NULL here because of is_orphaned_event(). In this
11053 * case inherit_event() will create individual events, similar to what
11054 * perf_group_detach() would do anyway.
11056 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
11057 child_ctr = inherit_event(sub, parent, parent_ctx,
11058 child, leader, child_ctx);
11059 if (IS_ERR(child_ctr))
11060 return PTR_ERR(child_ctr);
11062 leader->group_generation = parent_event->group_generation;
11067 * Creates the child task context and tries to inherit the event-group.
11069 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11070 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11071 * consistent with perf_event_release_kernel() removing all child events.
11078 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11079 struct perf_event_context *parent_ctx,
11080 struct task_struct *child, int ctxn,
11081 int *inherited_all)
11084 struct perf_event_context *child_ctx;
11086 if (!event->attr.inherit) {
11087 *inherited_all = 0;
11091 child_ctx = child->perf_event_ctxp[ctxn];
11094 * This is executed from the parent task context, so
11095 * inherit events that have been marked for cloning.
11096 * First allocate and initialize a context for the
11099 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11103 child->perf_event_ctxp[ctxn] = child_ctx;
11106 ret = inherit_group(event, parent, parent_ctx,
11110 *inherited_all = 0;
11116 * Initialize the perf_event context in task_struct
11118 static int perf_event_init_context(struct task_struct *child, int ctxn)
11120 struct perf_event_context *child_ctx, *parent_ctx;
11121 struct perf_event_context *cloned_ctx;
11122 struct perf_event *event;
11123 struct task_struct *parent = current;
11124 int inherited_all = 1;
11125 unsigned long flags;
11128 if (likely(!parent->perf_event_ctxp[ctxn]))
11132 * If the parent's context is a clone, pin it so it won't get
11133 * swapped under us.
11135 parent_ctx = perf_pin_task_context(parent, ctxn);
11140 * No need to check if parent_ctx != NULL here; since we saw
11141 * it non-NULL earlier, the only reason for it to become NULL
11142 * is if we exit, and since we're currently in the middle of
11143 * a fork we can't be exiting at the same time.
11147 * Lock the parent list. No need to lock the child - not PID
11148 * hashed yet and not running, so nobody can access it.
11150 mutex_lock(&parent_ctx->mutex);
11153 * We dont have to disable NMIs - we are only looking at
11154 * the list, not manipulating it:
11156 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
11157 ret = inherit_task_group(event, parent, parent_ctx,
11158 child, ctxn, &inherited_all);
11164 * We can't hold ctx->lock when iterating the ->flexible_group list due
11165 * to allocations, but we need to prevent rotation because
11166 * rotate_ctx() will change the list from interrupt context.
11168 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11169 parent_ctx->rotate_disable = 1;
11170 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11172 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
11173 ret = inherit_task_group(event, parent, parent_ctx,
11174 child, ctxn, &inherited_all);
11179 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11180 parent_ctx->rotate_disable = 0;
11182 child_ctx = child->perf_event_ctxp[ctxn];
11184 if (child_ctx && inherited_all) {
11186 * Mark the child context as a clone of the parent
11187 * context, or of whatever the parent is a clone of.
11189 * Note that if the parent is a clone, the holding of
11190 * parent_ctx->lock avoids it from being uncloned.
11192 cloned_ctx = parent_ctx->parent_ctx;
11194 child_ctx->parent_ctx = cloned_ctx;
11195 child_ctx->parent_gen = parent_ctx->parent_gen;
11197 child_ctx->parent_ctx = parent_ctx;
11198 child_ctx->parent_gen = parent_ctx->generation;
11200 get_ctx(child_ctx->parent_ctx);
11203 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11205 mutex_unlock(&parent_ctx->mutex);
11207 perf_unpin_context(parent_ctx);
11208 put_ctx(parent_ctx);
11214 * Initialize the perf_event context in task_struct
11216 int perf_event_init_task(struct task_struct *child)
11220 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11221 mutex_init(&child->perf_event_mutex);
11222 INIT_LIST_HEAD(&child->perf_event_list);
11224 for_each_task_context_nr(ctxn) {
11225 ret = perf_event_init_context(child, ctxn);
11227 perf_event_free_task(child);
11235 static void __init perf_event_init_all_cpus(void)
11237 struct swevent_htable *swhash;
11240 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11242 for_each_possible_cpu(cpu) {
11243 swhash = &per_cpu(swevent_htable, cpu);
11244 mutex_init(&swhash->hlist_mutex);
11245 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11247 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11248 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11250 #ifdef CONFIG_CGROUP_PERF
11251 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11253 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11257 void perf_swevent_init_cpu(unsigned int cpu)
11259 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11261 mutex_lock(&swhash->hlist_mutex);
11262 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11263 struct swevent_hlist *hlist;
11265 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11267 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11269 mutex_unlock(&swhash->hlist_mutex);
11272 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11273 static void __perf_event_exit_context(void *__info)
11275 struct perf_event_context *ctx = __info;
11276 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11277 struct perf_event *event;
11279 raw_spin_lock(&ctx->lock);
11280 list_for_each_entry(event, &ctx->event_list, event_entry)
11281 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11282 raw_spin_unlock(&ctx->lock);
11285 static void perf_event_exit_cpu_context(int cpu)
11287 struct perf_cpu_context *cpuctx;
11288 struct perf_event_context *ctx;
11291 mutex_lock(&pmus_lock);
11292 list_for_each_entry(pmu, &pmus, entry) {
11293 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11294 ctx = &cpuctx->ctx;
11296 mutex_lock(&ctx->mutex);
11297 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11298 cpuctx->online = 0;
11299 mutex_unlock(&ctx->mutex);
11301 cpumask_clear_cpu(cpu, perf_online_mask);
11302 mutex_unlock(&pmus_lock);
11306 static void perf_event_exit_cpu_context(int cpu) { }
11310 int perf_event_init_cpu(unsigned int cpu)
11312 struct perf_cpu_context *cpuctx;
11313 struct perf_event_context *ctx;
11316 perf_swevent_init_cpu(cpu);
11318 mutex_lock(&pmus_lock);
11319 cpumask_set_cpu(cpu, perf_online_mask);
11320 list_for_each_entry(pmu, &pmus, entry) {
11321 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11322 ctx = &cpuctx->ctx;
11324 mutex_lock(&ctx->mutex);
11325 cpuctx->online = 1;
11326 mutex_unlock(&ctx->mutex);
11328 mutex_unlock(&pmus_lock);
11333 int perf_event_exit_cpu(unsigned int cpu)
11335 perf_event_exit_cpu_context(cpu);
11340 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11344 for_each_online_cpu(cpu)
11345 perf_event_exit_cpu(cpu);
11351 * Run the perf reboot notifier at the very last possible moment so that
11352 * the generic watchdog code runs as long as possible.
11354 static struct notifier_block perf_reboot_notifier = {
11355 .notifier_call = perf_reboot,
11356 .priority = INT_MIN,
11359 void __init perf_event_init(void)
11363 idr_init(&pmu_idr);
11365 perf_event_init_all_cpus();
11366 init_srcu_struct(&pmus_srcu);
11367 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11368 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11369 perf_pmu_register(&perf_task_clock, NULL, -1);
11370 perf_tp_register();
11371 perf_event_init_cpu(smp_processor_id());
11372 register_reboot_notifier(&perf_reboot_notifier);
11374 ret = init_hw_breakpoint();
11375 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11378 * Build time assertion that we keep the data_head at the intended
11379 * location. IOW, validation we got the __reserved[] size right.
11381 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11385 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11388 struct perf_pmu_events_attr *pmu_attr =
11389 container_of(attr, struct perf_pmu_events_attr, attr);
11391 if (pmu_attr->event_str)
11392 return sprintf(page, "%s\n", pmu_attr->event_str);
11396 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11398 static int __init perf_event_sysfs_init(void)
11403 mutex_lock(&pmus_lock);
11405 ret = bus_register(&pmu_bus);
11409 list_for_each_entry(pmu, &pmus, entry) {
11410 if (!pmu->name || pmu->type < 0)
11413 ret = pmu_dev_alloc(pmu);
11414 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11416 pmu_bus_running = 1;
11420 mutex_unlock(&pmus_lock);
11424 device_initcall(perf_event_sysfs_init);
11426 #ifdef CONFIG_CGROUP_PERF
11427 static struct cgroup_subsys_state *
11428 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11430 struct perf_cgroup *jc;
11432 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11434 return ERR_PTR(-ENOMEM);
11436 jc->info = alloc_percpu(struct perf_cgroup_info);
11439 return ERR_PTR(-ENOMEM);
11445 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11447 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11449 free_percpu(jc->info);
11453 static int __perf_cgroup_move(void *info)
11455 struct task_struct *task = info;
11457 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11462 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11464 struct task_struct *task;
11465 struct cgroup_subsys_state *css;
11467 cgroup_taskset_for_each(task, css, tset)
11468 task_function_call(task, __perf_cgroup_move, task);
11471 struct cgroup_subsys perf_event_cgrp_subsys = {
11472 .css_alloc = perf_cgroup_css_alloc,
11473 .css_free = perf_cgroup_css_free,
11474 .attach = perf_cgroup_attach,
11476 * Implicitly enable on dfl hierarchy so that perf events can
11477 * always be filtered by cgroup2 path as long as perf_event
11478 * controller is not mounted on a legacy hierarchy.
11480 .implicit_on_dfl = true,
11483 #endif /* CONFIG_CGROUP_PERF */