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++;
1703 perf_event__header_size(group_leader);
1705 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1706 perf_event__header_size(pos);
1710 * Remove a event from the lists for its context.
1711 * Must be called with ctx->mutex and ctx->lock held.
1714 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1716 WARN_ON_ONCE(event->ctx != ctx);
1717 lockdep_assert_held(&ctx->lock);
1720 * We can have double detach due to exit/hot-unplug + close.
1722 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1725 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1727 list_update_cgroup_event(event, ctx, false);
1730 if (event->attr.inherit_stat)
1733 list_del_rcu(&event->event_entry);
1735 if (event->group_leader == event)
1736 list_del_init(&event->group_entry);
1738 update_group_times(event);
1741 * If event was in error state, then keep it
1742 * that way, otherwise bogus counts will be
1743 * returned on read(). The only way to get out
1744 * of error state is by explicit re-enabling
1747 if (event->state > PERF_EVENT_STATE_OFF)
1748 event->state = PERF_EVENT_STATE_OFF;
1753 static void perf_group_detach(struct perf_event *event)
1755 struct perf_event *sibling, *tmp;
1756 struct list_head *list = NULL;
1758 lockdep_assert_held(&event->ctx->lock);
1761 * We can have double detach due to exit/hot-unplug + close.
1763 if (!(event->attach_state & PERF_ATTACH_GROUP))
1766 event->attach_state &= ~PERF_ATTACH_GROUP;
1769 * If this is a sibling, remove it from its group.
1771 if (event->group_leader != event) {
1772 list_del_init(&event->group_entry);
1773 event->group_leader->nr_siblings--;
1777 if (!list_empty(&event->group_entry))
1778 list = &event->group_entry;
1781 * If this was a group event with sibling events then
1782 * upgrade the siblings to singleton events by adding them
1783 * to whatever list we are on.
1785 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1787 list_move_tail(&sibling->group_entry, list);
1788 sibling->group_leader = sibling;
1790 /* Inherit group flags from the previous leader */
1791 sibling->group_caps = event->group_caps;
1793 WARN_ON_ONCE(sibling->ctx != event->ctx);
1797 perf_event__header_size(event->group_leader);
1799 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1800 perf_event__header_size(tmp);
1803 static bool is_orphaned_event(struct perf_event *event)
1805 return event->state == PERF_EVENT_STATE_DEAD;
1808 static inline int __pmu_filter_match(struct perf_event *event)
1810 struct pmu *pmu = event->pmu;
1811 return pmu->filter_match ? pmu->filter_match(event) : 1;
1815 * Check whether we should attempt to schedule an event group based on
1816 * PMU-specific filtering. An event group can consist of HW and SW events,
1817 * potentially with a SW leader, so we must check all the filters, to
1818 * determine whether a group is schedulable:
1820 static inline int pmu_filter_match(struct perf_event *event)
1822 struct perf_event *child;
1824 if (!__pmu_filter_match(event))
1827 list_for_each_entry(child, &event->sibling_list, group_entry) {
1828 if (!__pmu_filter_match(child))
1836 event_filter_match(struct perf_event *event)
1838 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1839 perf_cgroup_match(event) && pmu_filter_match(event);
1843 event_sched_out(struct perf_event *event,
1844 struct perf_cpu_context *cpuctx,
1845 struct perf_event_context *ctx)
1847 u64 tstamp = perf_event_time(event);
1850 WARN_ON_ONCE(event->ctx != ctx);
1851 lockdep_assert_held(&ctx->lock);
1854 * An event which could not be activated because of
1855 * filter mismatch still needs to have its timings
1856 * maintained, otherwise bogus information is return
1857 * via read() for time_enabled, time_running:
1859 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1860 !event_filter_match(event)) {
1861 delta = tstamp - event->tstamp_stopped;
1862 event->tstamp_running += delta;
1863 event->tstamp_stopped = tstamp;
1866 if (event->state != PERF_EVENT_STATE_ACTIVE)
1869 perf_pmu_disable(event->pmu);
1871 event->tstamp_stopped = tstamp;
1872 event->pmu->del(event, 0);
1874 event->state = PERF_EVENT_STATE_INACTIVE;
1875 if (event->pending_disable) {
1876 event->pending_disable = 0;
1877 event->state = PERF_EVENT_STATE_OFF;
1880 if (!is_software_event(event))
1881 cpuctx->active_oncpu--;
1882 if (!--ctx->nr_active)
1883 perf_event_ctx_deactivate(ctx);
1884 if (event->attr.freq && event->attr.sample_freq)
1886 if (event->attr.exclusive || !cpuctx->active_oncpu)
1887 cpuctx->exclusive = 0;
1889 perf_pmu_enable(event->pmu);
1893 group_sched_out(struct perf_event *group_event,
1894 struct perf_cpu_context *cpuctx,
1895 struct perf_event_context *ctx)
1897 struct perf_event *event;
1898 int state = group_event->state;
1900 perf_pmu_disable(ctx->pmu);
1902 event_sched_out(group_event, cpuctx, ctx);
1905 * Schedule out siblings (if any):
1907 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1908 event_sched_out(event, cpuctx, ctx);
1910 perf_pmu_enable(ctx->pmu);
1912 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1913 cpuctx->exclusive = 0;
1916 #define DETACH_GROUP 0x01UL
1919 * Cross CPU call to remove a performance event
1921 * We disable the event on the hardware level first. After that we
1922 * remove it from the context list.
1925 __perf_remove_from_context(struct perf_event *event,
1926 struct perf_cpu_context *cpuctx,
1927 struct perf_event_context *ctx,
1930 unsigned long flags = (unsigned long)info;
1932 event_sched_out(event, cpuctx, ctx);
1933 if (flags & DETACH_GROUP)
1934 perf_group_detach(event);
1935 list_del_event(event, ctx);
1937 if (!ctx->nr_events && ctx->is_active) {
1940 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1941 cpuctx->task_ctx = NULL;
1947 * Remove the event from a task's (or a CPU's) list of events.
1949 * If event->ctx is a cloned context, callers must make sure that
1950 * every task struct that event->ctx->task could possibly point to
1951 * remains valid. This is OK when called from perf_release since
1952 * that only calls us on the top-level context, which can't be a clone.
1953 * When called from perf_event_exit_task, it's OK because the
1954 * context has been detached from its task.
1956 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1958 struct perf_event_context *ctx = event->ctx;
1960 lockdep_assert_held(&ctx->mutex);
1962 event_function_call(event, __perf_remove_from_context, (void *)flags);
1965 * The above event_function_call() can NO-OP when it hits
1966 * TASK_TOMBSTONE. In that case we must already have been detached
1967 * from the context (by perf_event_exit_event()) but the grouping
1968 * might still be in-tact.
1970 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1971 if ((flags & DETACH_GROUP) &&
1972 (event->attach_state & PERF_ATTACH_GROUP)) {
1974 * Since in that case we cannot possibly be scheduled, simply
1977 raw_spin_lock_irq(&ctx->lock);
1978 perf_group_detach(event);
1979 raw_spin_unlock_irq(&ctx->lock);
1984 * Cross CPU call to disable a performance event
1986 static void __perf_event_disable(struct perf_event *event,
1987 struct perf_cpu_context *cpuctx,
1988 struct perf_event_context *ctx,
1991 if (event->state < PERF_EVENT_STATE_INACTIVE)
1994 update_context_time(ctx);
1995 update_cgrp_time_from_event(event);
1996 update_group_times(event);
1997 if (event == event->group_leader)
1998 group_sched_out(event, cpuctx, ctx);
2000 event_sched_out(event, cpuctx, ctx);
2001 event->state = PERF_EVENT_STATE_OFF;
2007 * If event->ctx is a cloned context, callers must make sure that
2008 * every task struct that event->ctx->task could possibly point to
2009 * remains valid. This condition is satisifed when called through
2010 * perf_event_for_each_child or perf_event_for_each because they
2011 * hold the top-level event's child_mutex, so any descendant that
2012 * goes to exit will block in perf_event_exit_event().
2014 * When called from perf_pending_event it's OK because event->ctx
2015 * is the current context on this CPU and preemption is disabled,
2016 * hence we can't get into perf_event_task_sched_out for this context.
2018 static void _perf_event_disable(struct perf_event *event)
2020 struct perf_event_context *ctx = event->ctx;
2022 raw_spin_lock_irq(&ctx->lock);
2023 if (event->state <= PERF_EVENT_STATE_OFF) {
2024 raw_spin_unlock_irq(&ctx->lock);
2027 raw_spin_unlock_irq(&ctx->lock);
2029 event_function_call(event, __perf_event_disable, NULL);
2032 void perf_event_disable_local(struct perf_event *event)
2034 event_function_local(event, __perf_event_disable, NULL);
2038 * Strictly speaking kernel users cannot create groups and therefore this
2039 * interface does not need the perf_event_ctx_lock() magic.
2041 void perf_event_disable(struct perf_event *event)
2043 struct perf_event_context *ctx;
2045 ctx = perf_event_ctx_lock(event);
2046 _perf_event_disable(event);
2047 perf_event_ctx_unlock(event, ctx);
2049 EXPORT_SYMBOL_GPL(perf_event_disable);
2051 void perf_event_disable_inatomic(struct perf_event *event)
2053 event->pending_disable = 1;
2054 irq_work_queue(&event->pending);
2057 static void perf_set_shadow_time(struct perf_event *event,
2058 struct perf_event_context *ctx,
2062 * use the correct time source for the time snapshot
2064 * We could get by without this by leveraging the
2065 * fact that to get to this function, the caller
2066 * has most likely already called update_context_time()
2067 * and update_cgrp_time_xx() and thus both timestamp
2068 * are identical (or very close). Given that tstamp is,
2069 * already adjusted for cgroup, we could say that:
2070 * tstamp - ctx->timestamp
2072 * tstamp - cgrp->timestamp.
2074 * Then, in perf_output_read(), the calculation would
2075 * work with no changes because:
2076 * - event is guaranteed scheduled in
2077 * - no scheduled out in between
2078 * - thus the timestamp would be the same
2080 * But this is a bit hairy.
2082 * So instead, we have an explicit cgroup call to remain
2083 * within the time time source all along. We believe it
2084 * is cleaner and simpler to understand.
2086 if (is_cgroup_event(event))
2087 perf_cgroup_set_shadow_time(event, tstamp);
2089 event->shadow_ctx_time = tstamp - ctx->timestamp;
2092 #define MAX_INTERRUPTS (~0ULL)
2094 static void perf_log_throttle(struct perf_event *event, int enable);
2095 static void perf_log_itrace_start(struct perf_event *event);
2098 event_sched_in(struct perf_event *event,
2099 struct perf_cpu_context *cpuctx,
2100 struct perf_event_context *ctx)
2102 u64 tstamp = perf_event_time(event);
2105 lockdep_assert_held(&ctx->lock);
2107 if (event->state <= PERF_EVENT_STATE_OFF)
2110 WRITE_ONCE(event->oncpu, smp_processor_id());
2112 * Order event::oncpu write to happen before the ACTIVE state
2116 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2119 * Unthrottle events, since we scheduled we might have missed several
2120 * ticks already, also for a heavily scheduling task there is little
2121 * guarantee it'll get a tick in a timely manner.
2123 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2124 perf_log_throttle(event, 1);
2125 event->hw.interrupts = 0;
2129 * The new state must be visible before we turn it on in the hardware:
2133 perf_pmu_disable(event->pmu);
2135 perf_set_shadow_time(event, ctx, tstamp);
2137 perf_log_itrace_start(event);
2139 if (event->pmu->add(event, PERF_EF_START)) {
2140 event->state = PERF_EVENT_STATE_INACTIVE;
2146 event->tstamp_running += tstamp - event->tstamp_stopped;
2148 if (!is_software_event(event))
2149 cpuctx->active_oncpu++;
2150 if (!ctx->nr_active++)
2151 perf_event_ctx_activate(ctx);
2152 if (event->attr.freq && event->attr.sample_freq)
2155 if (event->attr.exclusive)
2156 cpuctx->exclusive = 1;
2159 perf_pmu_enable(event->pmu);
2165 group_sched_in(struct perf_event *group_event,
2166 struct perf_cpu_context *cpuctx,
2167 struct perf_event_context *ctx)
2169 struct perf_event *event, *partial_group = NULL;
2170 struct pmu *pmu = ctx->pmu;
2171 u64 now = ctx->time;
2172 bool simulate = false;
2174 if (group_event->state == PERF_EVENT_STATE_OFF)
2177 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2179 if (event_sched_in(group_event, cpuctx, ctx)) {
2180 pmu->cancel_txn(pmu);
2181 perf_mux_hrtimer_restart(cpuctx);
2186 * Schedule in siblings as one group (if any):
2188 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2189 if (event_sched_in(event, cpuctx, ctx)) {
2190 partial_group = event;
2195 if (!pmu->commit_txn(pmu))
2200 * Groups can be scheduled in as one unit only, so undo any
2201 * partial group before returning:
2202 * The events up to the failed event are scheduled out normally,
2203 * tstamp_stopped will be updated.
2205 * The failed events and the remaining siblings need to have
2206 * their timings updated as if they had gone thru event_sched_in()
2207 * and event_sched_out(). This is required to get consistent timings
2208 * across the group. This also takes care of the case where the group
2209 * could never be scheduled by ensuring tstamp_stopped is set to mark
2210 * the time the event was actually stopped, such that time delta
2211 * calculation in update_event_times() is correct.
2213 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2214 if (event == partial_group)
2218 event->tstamp_running += now - event->tstamp_stopped;
2219 event->tstamp_stopped = now;
2221 event_sched_out(event, cpuctx, ctx);
2224 event_sched_out(group_event, cpuctx, ctx);
2226 pmu->cancel_txn(pmu);
2228 perf_mux_hrtimer_restart(cpuctx);
2234 * Work out whether we can put this event group on the CPU now.
2236 static int group_can_go_on(struct perf_event *event,
2237 struct perf_cpu_context *cpuctx,
2241 * Groups consisting entirely of software events can always go on.
2243 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2246 * If an exclusive group is already on, no other hardware
2249 if (cpuctx->exclusive)
2252 * If this group is exclusive and there are already
2253 * events on the CPU, it can't go on.
2255 if (event->attr.exclusive && cpuctx->active_oncpu)
2258 * Otherwise, try to add it if all previous groups were able
2265 * Complement to update_event_times(). This computes the tstamp_* values to
2266 * continue 'enabled' state from @now, and effectively discards the time
2267 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2268 * just switched (context) time base).
2270 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2271 * cannot have been scheduled in yet. And going into INACTIVE state means
2272 * '@event->tstamp_stopped = @now'.
2274 * Thus given the rules of update_event_times():
2276 * total_time_enabled = tstamp_stopped - tstamp_enabled
2277 * total_time_running = tstamp_stopped - tstamp_running
2279 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2282 static void __perf_event_enable_time(struct perf_event *event, u64 now)
2284 WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE);
2286 event->tstamp_stopped = now;
2287 event->tstamp_enabled = now - event->total_time_enabled;
2288 event->tstamp_running = now - event->total_time_running;
2291 static void add_event_to_ctx(struct perf_event *event,
2292 struct perf_event_context *ctx)
2294 u64 tstamp = perf_event_time(event);
2296 list_add_event(event, ctx);
2297 perf_group_attach(event);
2299 * We can be called with event->state == STATE_OFF when we create with
2300 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2302 if (event->state == PERF_EVENT_STATE_INACTIVE)
2303 __perf_event_enable_time(event, tstamp);
2306 static void ctx_sched_out(struct perf_event_context *ctx,
2307 struct perf_cpu_context *cpuctx,
2308 enum event_type_t event_type);
2310 ctx_sched_in(struct perf_event_context *ctx,
2311 struct perf_cpu_context *cpuctx,
2312 enum event_type_t event_type,
2313 struct task_struct *task);
2315 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2316 struct perf_event_context *ctx,
2317 enum event_type_t event_type)
2319 if (!cpuctx->task_ctx)
2322 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2325 ctx_sched_out(ctx, cpuctx, event_type);
2328 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2329 struct perf_event_context *ctx,
2330 struct task_struct *task)
2332 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2334 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2335 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2337 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2341 * We want to maintain the following priority of scheduling:
2342 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2343 * - task pinned (EVENT_PINNED)
2344 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2345 * - task flexible (EVENT_FLEXIBLE).
2347 * In order to avoid unscheduling and scheduling back in everything every
2348 * time an event is added, only do it for the groups of equal priority and
2351 * This can be called after a batch operation on task events, in which case
2352 * event_type is a bit mask of the types of events involved. For CPU events,
2353 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2355 static void ctx_resched(struct perf_cpu_context *cpuctx,
2356 struct perf_event_context *task_ctx,
2357 enum event_type_t event_type)
2359 enum event_type_t ctx_event_type;
2360 bool cpu_event = !!(event_type & EVENT_CPU);
2363 * If pinned groups are involved, flexible groups also need to be
2366 if (event_type & EVENT_PINNED)
2367 event_type |= EVENT_FLEXIBLE;
2369 ctx_event_type = event_type & EVENT_ALL;
2371 perf_pmu_disable(cpuctx->ctx.pmu);
2373 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2376 * Decide which cpu ctx groups to schedule out based on the types
2377 * of events that caused rescheduling:
2378 * - EVENT_CPU: schedule out corresponding groups;
2379 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2380 * - otherwise, do nothing more.
2383 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2384 else if (ctx_event_type & EVENT_PINNED)
2385 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2387 perf_event_sched_in(cpuctx, task_ctx, current);
2388 perf_pmu_enable(cpuctx->ctx.pmu);
2392 * Cross CPU call to install and enable a performance event
2394 * Very similar to remote_function() + event_function() but cannot assume that
2395 * things like ctx->is_active and cpuctx->task_ctx are set.
2397 static int __perf_install_in_context(void *info)
2399 struct perf_event *event = info;
2400 struct perf_event_context *ctx = event->ctx;
2401 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2402 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2403 bool reprogram = true;
2406 raw_spin_lock(&cpuctx->ctx.lock);
2408 raw_spin_lock(&ctx->lock);
2411 reprogram = (ctx->task == current);
2414 * If the task is running, it must be running on this CPU,
2415 * otherwise we cannot reprogram things.
2417 * If its not running, we don't care, ctx->lock will
2418 * serialize against it becoming runnable.
2420 if (task_curr(ctx->task) && !reprogram) {
2425 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2426 } else if (task_ctx) {
2427 raw_spin_lock(&task_ctx->lock);
2430 #ifdef CONFIG_CGROUP_PERF
2431 if (is_cgroup_event(event)) {
2433 * If the current cgroup doesn't match the event's
2434 * cgroup, we should not try to schedule it.
2436 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2437 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2438 event->cgrp->css.cgroup);
2443 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2444 add_event_to_ctx(event, ctx);
2445 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2447 add_event_to_ctx(event, ctx);
2451 perf_ctx_unlock(cpuctx, task_ctx);
2457 * Attach a performance event to a context.
2459 * Very similar to event_function_call, see comment there.
2462 perf_install_in_context(struct perf_event_context *ctx,
2463 struct perf_event *event,
2466 struct task_struct *task = READ_ONCE(ctx->task);
2468 lockdep_assert_held(&ctx->mutex);
2470 if (event->cpu != -1)
2474 * Ensures that if we can observe event->ctx, both the event and ctx
2475 * will be 'complete'. See perf_iterate_sb_cpu().
2477 smp_store_release(&event->ctx, ctx);
2480 cpu_function_call(cpu, __perf_install_in_context, event);
2485 * Should not happen, we validate the ctx is still alive before calling.
2487 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2491 * Installing events is tricky because we cannot rely on ctx->is_active
2492 * to be set in case this is the nr_events 0 -> 1 transition.
2494 * Instead we use task_curr(), which tells us if the task is running.
2495 * However, since we use task_curr() outside of rq::lock, we can race
2496 * against the actual state. This means the result can be wrong.
2498 * If we get a false positive, we retry, this is harmless.
2500 * If we get a false negative, things are complicated. If we are after
2501 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2502 * value must be correct. If we're before, it doesn't matter since
2503 * perf_event_context_sched_in() will program the counter.
2505 * However, this hinges on the remote context switch having observed
2506 * our task->perf_event_ctxp[] store, such that it will in fact take
2507 * ctx::lock in perf_event_context_sched_in().
2509 * We do this by task_function_call(), if the IPI fails to hit the task
2510 * we know any future context switch of task must see the
2511 * perf_event_ctpx[] store.
2515 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2516 * task_cpu() load, such that if the IPI then does not find the task
2517 * running, a future context switch of that task must observe the
2522 if (!task_function_call(task, __perf_install_in_context, event))
2525 raw_spin_lock_irq(&ctx->lock);
2527 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2529 * Cannot happen because we already checked above (which also
2530 * cannot happen), and we hold ctx->mutex, which serializes us
2531 * against perf_event_exit_task_context().
2533 raw_spin_unlock_irq(&ctx->lock);
2537 * If the task is not running, ctx->lock will avoid it becoming so,
2538 * thus we can safely install the event.
2540 if (task_curr(task)) {
2541 raw_spin_unlock_irq(&ctx->lock);
2544 add_event_to_ctx(event, ctx);
2545 raw_spin_unlock_irq(&ctx->lock);
2549 * Put a event into inactive state and update time fields.
2550 * Enabling the leader of a group effectively enables all
2551 * the group members that aren't explicitly disabled, so we
2552 * have to update their ->tstamp_enabled also.
2553 * Note: this works for group members as well as group leaders
2554 * since the non-leader members' sibling_lists will be empty.
2556 static void __perf_event_mark_enabled(struct perf_event *event)
2558 struct perf_event *sub;
2559 u64 tstamp = perf_event_time(event);
2561 event->state = PERF_EVENT_STATE_INACTIVE;
2562 __perf_event_enable_time(event, tstamp);
2563 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2564 /* XXX should not be > INACTIVE if event isn't */
2565 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2566 __perf_event_enable_time(sub, tstamp);
2571 * Cross CPU call to enable a performance event
2573 static void __perf_event_enable(struct perf_event *event,
2574 struct perf_cpu_context *cpuctx,
2575 struct perf_event_context *ctx,
2578 struct perf_event *leader = event->group_leader;
2579 struct perf_event_context *task_ctx;
2581 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2582 event->state <= PERF_EVENT_STATE_ERROR)
2586 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2588 __perf_event_mark_enabled(event);
2590 if (!ctx->is_active)
2593 if (!event_filter_match(event)) {
2594 if (is_cgroup_event(event))
2595 perf_cgroup_defer_enabled(event);
2596 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2601 * If the event is in a group and isn't the group leader,
2602 * then don't put it on unless the group is on.
2604 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2605 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2609 task_ctx = cpuctx->task_ctx;
2611 WARN_ON_ONCE(task_ctx != ctx);
2613 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2619 * If event->ctx is a cloned context, callers must make sure that
2620 * every task struct that event->ctx->task could possibly point to
2621 * remains valid. This condition is satisfied when called through
2622 * perf_event_for_each_child or perf_event_for_each as described
2623 * for perf_event_disable.
2625 static void _perf_event_enable(struct perf_event *event)
2627 struct perf_event_context *ctx = event->ctx;
2629 raw_spin_lock_irq(&ctx->lock);
2630 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2631 event->state < PERF_EVENT_STATE_ERROR) {
2632 raw_spin_unlock_irq(&ctx->lock);
2637 * If the event is in error state, clear that first.
2639 * That way, if we see the event in error state below, we know that it
2640 * has gone back into error state, as distinct from the task having
2641 * been scheduled away before the cross-call arrived.
2643 if (event->state == PERF_EVENT_STATE_ERROR)
2644 event->state = PERF_EVENT_STATE_OFF;
2645 raw_spin_unlock_irq(&ctx->lock);
2647 event_function_call(event, __perf_event_enable, NULL);
2651 * See perf_event_disable();
2653 void perf_event_enable(struct perf_event *event)
2655 struct perf_event_context *ctx;
2657 ctx = perf_event_ctx_lock(event);
2658 _perf_event_enable(event);
2659 perf_event_ctx_unlock(event, ctx);
2661 EXPORT_SYMBOL_GPL(perf_event_enable);
2663 struct stop_event_data {
2664 struct perf_event *event;
2665 unsigned int restart;
2668 static int __perf_event_stop(void *info)
2670 struct stop_event_data *sd = info;
2671 struct perf_event *event = sd->event;
2673 /* if it's already INACTIVE, do nothing */
2674 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2677 /* matches smp_wmb() in event_sched_in() */
2681 * There is a window with interrupts enabled before we get here,
2682 * so we need to check again lest we try to stop another CPU's event.
2684 if (READ_ONCE(event->oncpu) != smp_processor_id())
2687 event->pmu->stop(event, PERF_EF_UPDATE);
2690 * May race with the actual stop (through perf_pmu_output_stop()),
2691 * but it is only used for events with AUX ring buffer, and such
2692 * events will refuse to restart because of rb::aux_mmap_count==0,
2693 * see comments in perf_aux_output_begin().
2695 * Since this is happening on a event-local CPU, no trace is lost
2699 event->pmu->start(event, 0);
2704 static int perf_event_stop(struct perf_event *event, int restart)
2706 struct stop_event_data sd = {
2713 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2716 /* matches smp_wmb() in event_sched_in() */
2720 * We only want to restart ACTIVE events, so if the event goes
2721 * inactive here (event->oncpu==-1), there's nothing more to do;
2722 * fall through with ret==-ENXIO.
2724 ret = cpu_function_call(READ_ONCE(event->oncpu),
2725 __perf_event_stop, &sd);
2726 } while (ret == -EAGAIN);
2732 * In order to contain the amount of racy and tricky in the address filter
2733 * configuration management, it is a two part process:
2735 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2736 * we update the addresses of corresponding vmas in
2737 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2738 * (p2) when an event is scheduled in (pmu::add), it calls
2739 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2740 * if the generation has changed since the previous call.
2742 * If (p1) happens while the event is active, we restart it to force (p2).
2744 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2745 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2747 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2748 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2750 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2753 void perf_event_addr_filters_sync(struct perf_event *event)
2755 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2757 if (!has_addr_filter(event))
2760 raw_spin_lock(&ifh->lock);
2761 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2762 event->pmu->addr_filters_sync(event);
2763 event->hw.addr_filters_gen = event->addr_filters_gen;
2765 raw_spin_unlock(&ifh->lock);
2767 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2769 static int _perf_event_refresh(struct perf_event *event, int refresh)
2772 * not supported on inherited events
2774 if (event->attr.inherit || !is_sampling_event(event))
2777 atomic_add(refresh, &event->event_limit);
2778 _perf_event_enable(event);
2784 * See perf_event_disable()
2786 int perf_event_refresh(struct perf_event *event, int refresh)
2788 struct perf_event_context *ctx;
2791 ctx = perf_event_ctx_lock(event);
2792 ret = _perf_event_refresh(event, refresh);
2793 perf_event_ctx_unlock(event, ctx);
2797 EXPORT_SYMBOL_GPL(perf_event_refresh);
2799 static void ctx_sched_out(struct perf_event_context *ctx,
2800 struct perf_cpu_context *cpuctx,
2801 enum event_type_t event_type)
2803 int is_active = ctx->is_active;
2804 struct perf_event *event;
2806 lockdep_assert_held(&ctx->lock);
2808 if (likely(!ctx->nr_events)) {
2810 * See __perf_remove_from_context().
2812 WARN_ON_ONCE(ctx->is_active);
2814 WARN_ON_ONCE(cpuctx->task_ctx);
2818 ctx->is_active &= ~event_type;
2819 if (!(ctx->is_active & EVENT_ALL))
2823 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2824 if (!ctx->is_active)
2825 cpuctx->task_ctx = NULL;
2829 * Always update time if it was set; not only when it changes.
2830 * Otherwise we can 'forget' to update time for any but the last
2831 * context we sched out. For example:
2833 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2834 * ctx_sched_out(.event_type = EVENT_PINNED)
2836 * would only update time for the pinned events.
2838 if (is_active & EVENT_TIME) {
2839 /* update (and stop) ctx time */
2840 update_context_time(ctx);
2841 update_cgrp_time_from_cpuctx(cpuctx);
2844 is_active ^= ctx->is_active; /* changed bits */
2846 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2849 perf_pmu_disable(ctx->pmu);
2850 if (is_active & EVENT_PINNED) {
2851 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2852 group_sched_out(event, cpuctx, ctx);
2855 if (is_active & EVENT_FLEXIBLE) {
2856 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2857 group_sched_out(event, cpuctx, ctx);
2859 perf_pmu_enable(ctx->pmu);
2863 * Test whether two contexts are equivalent, i.e. whether they have both been
2864 * cloned from the same version of the same context.
2866 * Equivalence is measured using a generation number in the context that is
2867 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2868 * and list_del_event().
2870 static int context_equiv(struct perf_event_context *ctx1,
2871 struct perf_event_context *ctx2)
2873 lockdep_assert_held(&ctx1->lock);
2874 lockdep_assert_held(&ctx2->lock);
2876 /* Pinning disables the swap optimization */
2877 if (ctx1->pin_count || ctx2->pin_count)
2880 /* If ctx1 is the parent of ctx2 */
2881 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2884 /* If ctx2 is the parent of ctx1 */
2885 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2889 * If ctx1 and ctx2 have the same parent; we flatten the parent
2890 * hierarchy, see perf_event_init_context().
2892 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2893 ctx1->parent_gen == ctx2->parent_gen)
2900 static void __perf_event_sync_stat(struct perf_event *event,
2901 struct perf_event *next_event)
2905 if (!event->attr.inherit_stat)
2909 * Update the event value, we cannot use perf_event_read()
2910 * because we're in the middle of a context switch and have IRQs
2911 * disabled, which upsets smp_call_function_single(), however
2912 * we know the event must be on the current CPU, therefore we
2913 * don't need to use it.
2915 switch (event->state) {
2916 case PERF_EVENT_STATE_ACTIVE:
2917 event->pmu->read(event);
2920 case PERF_EVENT_STATE_INACTIVE:
2921 update_event_times(event);
2929 * In order to keep per-task stats reliable we need to flip the event
2930 * values when we flip the contexts.
2932 value = local64_read(&next_event->count);
2933 value = local64_xchg(&event->count, value);
2934 local64_set(&next_event->count, value);
2936 swap(event->total_time_enabled, next_event->total_time_enabled);
2937 swap(event->total_time_running, next_event->total_time_running);
2940 * Since we swizzled the values, update the user visible data too.
2942 perf_event_update_userpage(event);
2943 perf_event_update_userpage(next_event);
2946 static void perf_event_sync_stat(struct perf_event_context *ctx,
2947 struct perf_event_context *next_ctx)
2949 struct perf_event *event, *next_event;
2954 update_context_time(ctx);
2956 event = list_first_entry(&ctx->event_list,
2957 struct perf_event, event_entry);
2959 next_event = list_first_entry(&next_ctx->event_list,
2960 struct perf_event, event_entry);
2962 while (&event->event_entry != &ctx->event_list &&
2963 &next_event->event_entry != &next_ctx->event_list) {
2965 __perf_event_sync_stat(event, next_event);
2967 event = list_next_entry(event, event_entry);
2968 next_event = list_next_entry(next_event, event_entry);
2972 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2973 struct task_struct *next)
2975 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2976 struct perf_event_context *next_ctx;
2977 struct perf_event_context *parent, *next_parent;
2978 struct perf_cpu_context *cpuctx;
2984 cpuctx = __get_cpu_context(ctx);
2985 if (!cpuctx->task_ctx)
2989 next_ctx = next->perf_event_ctxp[ctxn];
2993 parent = rcu_dereference(ctx->parent_ctx);
2994 next_parent = rcu_dereference(next_ctx->parent_ctx);
2996 /* If neither context have a parent context; they cannot be clones. */
2997 if (!parent && !next_parent)
3000 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3002 * Looks like the two contexts are clones, so we might be
3003 * able to optimize the context switch. We lock both
3004 * contexts and check that they are clones under the
3005 * lock (including re-checking that neither has been
3006 * uncloned in the meantime). It doesn't matter which
3007 * order we take the locks because no other cpu could
3008 * be trying to lock both of these tasks.
3010 raw_spin_lock(&ctx->lock);
3011 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3012 if (context_equiv(ctx, next_ctx)) {
3013 WRITE_ONCE(ctx->task, next);
3014 WRITE_ONCE(next_ctx->task, task);
3016 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3019 * RCU_INIT_POINTER here is safe because we've not
3020 * modified the ctx and the above modification of
3021 * ctx->task and ctx->task_ctx_data are immaterial
3022 * since those values are always verified under
3023 * ctx->lock which we're now holding.
3025 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3026 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3030 perf_event_sync_stat(ctx, next_ctx);
3032 raw_spin_unlock(&next_ctx->lock);
3033 raw_spin_unlock(&ctx->lock);
3039 raw_spin_lock(&ctx->lock);
3040 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3041 raw_spin_unlock(&ctx->lock);
3045 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3047 void perf_sched_cb_dec(struct pmu *pmu)
3049 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3051 this_cpu_dec(perf_sched_cb_usages);
3053 if (!--cpuctx->sched_cb_usage)
3054 list_del(&cpuctx->sched_cb_entry);
3058 void perf_sched_cb_inc(struct pmu *pmu)
3060 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3062 if (!cpuctx->sched_cb_usage++)
3063 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3065 this_cpu_inc(perf_sched_cb_usages);
3069 * This function provides the context switch callback to the lower code
3070 * layer. It is invoked ONLY when the context switch callback is enabled.
3072 * This callback is relevant even to per-cpu events; for example multi event
3073 * PEBS requires this to provide PID/TID information. This requires we flush
3074 * all queued PEBS records before we context switch to a new task.
3076 static void perf_pmu_sched_task(struct task_struct *prev,
3077 struct task_struct *next,
3080 struct perf_cpu_context *cpuctx;
3086 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3087 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3089 if (WARN_ON_ONCE(!pmu->sched_task))
3092 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3093 perf_pmu_disable(pmu);
3095 pmu->sched_task(cpuctx->task_ctx, sched_in);
3097 perf_pmu_enable(pmu);
3098 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3102 static void perf_event_switch(struct task_struct *task,
3103 struct task_struct *next_prev, bool sched_in);
3105 #define for_each_task_context_nr(ctxn) \
3106 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3109 * Called from scheduler to remove the events of the current task,
3110 * with interrupts disabled.
3112 * We stop each event and update the event value in event->count.
3114 * This does not protect us against NMI, but disable()
3115 * sets the disabled bit in the control field of event _before_
3116 * accessing the event control register. If a NMI hits, then it will
3117 * not restart the event.
3119 void __perf_event_task_sched_out(struct task_struct *task,
3120 struct task_struct *next)
3124 if (__this_cpu_read(perf_sched_cb_usages))
3125 perf_pmu_sched_task(task, next, false);
3127 if (atomic_read(&nr_switch_events))
3128 perf_event_switch(task, next, false);
3130 for_each_task_context_nr(ctxn)
3131 perf_event_context_sched_out(task, ctxn, next);
3134 * if cgroup events exist on this CPU, then we need
3135 * to check if we have to switch out PMU state.
3136 * cgroup event are system-wide mode only
3138 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3139 perf_cgroup_sched_out(task, next);
3143 * Called with IRQs disabled
3145 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3146 enum event_type_t event_type)
3148 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3152 ctx_pinned_sched_in(struct perf_event_context *ctx,
3153 struct perf_cpu_context *cpuctx)
3155 struct perf_event *event;
3157 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3158 if (event->state <= PERF_EVENT_STATE_OFF)
3160 if (!event_filter_match(event))
3163 /* may need to reset tstamp_enabled */
3164 if (is_cgroup_event(event))
3165 perf_cgroup_mark_enabled(event, ctx);
3167 if (group_can_go_on(event, cpuctx, 1))
3168 group_sched_in(event, cpuctx, ctx);
3171 * If this pinned group hasn't been scheduled,
3172 * put it in error state.
3174 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3175 update_group_times(event);
3176 event->state = PERF_EVENT_STATE_ERROR;
3182 ctx_flexible_sched_in(struct perf_event_context *ctx,
3183 struct perf_cpu_context *cpuctx)
3185 struct perf_event *event;
3188 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3189 /* Ignore events in OFF or ERROR state */
3190 if (event->state <= PERF_EVENT_STATE_OFF)
3193 * Listen to the 'cpu' scheduling filter constraint
3196 if (!event_filter_match(event))
3199 /* may need to reset tstamp_enabled */
3200 if (is_cgroup_event(event))
3201 perf_cgroup_mark_enabled(event, ctx);
3203 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3204 if (group_sched_in(event, cpuctx, ctx))
3211 ctx_sched_in(struct perf_event_context *ctx,
3212 struct perf_cpu_context *cpuctx,
3213 enum event_type_t event_type,
3214 struct task_struct *task)
3216 int is_active = ctx->is_active;
3219 lockdep_assert_held(&ctx->lock);
3221 if (likely(!ctx->nr_events))
3224 ctx->is_active |= (event_type | EVENT_TIME);
3227 cpuctx->task_ctx = ctx;
3229 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3232 is_active ^= ctx->is_active; /* changed bits */
3234 if (is_active & EVENT_TIME) {
3235 /* start ctx time */
3237 ctx->timestamp = now;
3238 perf_cgroup_set_timestamp(task, ctx);
3242 * First go through the list and put on any pinned groups
3243 * in order to give them the best chance of going on.
3245 if (is_active & EVENT_PINNED)
3246 ctx_pinned_sched_in(ctx, cpuctx);
3248 /* Then walk through the lower prio flexible groups */
3249 if (is_active & EVENT_FLEXIBLE)
3250 ctx_flexible_sched_in(ctx, cpuctx);
3253 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3254 enum event_type_t event_type,
3255 struct task_struct *task)
3257 struct perf_event_context *ctx = &cpuctx->ctx;
3259 ctx_sched_in(ctx, cpuctx, event_type, task);
3262 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3263 struct task_struct *task)
3265 struct perf_cpu_context *cpuctx;
3267 cpuctx = __get_cpu_context(ctx);
3268 if (cpuctx->task_ctx == ctx)
3271 perf_ctx_lock(cpuctx, ctx);
3273 * We must check ctx->nr_events while holding ctx->lock, such
3274 * that we serialize against perf_install_in_context().
3276 if (!ctx->nr_events)
3279 perf_pmu_disable(ctx->pmu);
3281 * We want to keep the following priority order:
3282 * cpu pinned (that don't need to move), task pinned,
3283 * cpu flexible, task flexible.
3285 * However, if task's ctx is not carrying any pinned
3286 * events, no need to flip the cpuctx's events around.
3288 if (!list_empty(&ctx->pinned_groups))
3289 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3290 perf_event_sched_in(cpuctx, ctx, task);
3291 perf_pmu_enable(ctx->pmu);
3294 perf_ctx_unlock(cpuctx, ctx);
3298 * Called from scheduler to add the events of the current task
3299 * with interrupts disabled.
3301 * We restore the event value and then enable it.
3303 * This does not protect us against NMI, but enable()
3304 * sets the enabled bit in the control field of event _before_
3305 * accessing the event control register. If a NMI hits, then it will
3306 * keep the event running.
3308 void __perf_event_task_sched_in(struct task_struct *prev,
3309 struct task_struct *task)
3311 struct perf_event_context *ctx;
3315 * If cgroup events exist on this CPU, then we need to check if we have
3316 * to switch in PMU state; cgroup event are system-wide mode only.
3318 * Since cgroup events are CPU events, we must schedule these in before
3319 * we schedule in the task events.
3321 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3322 perf_cgroup_sched_in(prev, task);
3324 for_each_task_context_nr(ctxn) {
3325 ctx = task->perf_event_ctxp[ctxn];
3329 perf_event_context_sched_in(ctx, task);
3332 if (atomic_read(&nr_switch_events))
3333 perf_event_switch(task, prev, true);
3335 if (__this_cpu_read(perf_sched_cb_usages))
3336 perf_pmu_sched_task(prev, task, true);
3339 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3341 u64 frequency = event->attr.sample_freq;
3342 u64 sec = NSEC_PER_SEC;
3343 u64 divisor, dividend;
3345 int count_fls, nsec_fls, frequency_fls, sec_fls;
3347 count_fls = fls64(count);
3348 nsec_fls = fls64(nsec);
3349 frequency_fls = fls64(frequency);
3353 * We got @count in @nsec, with a target of sample_freq HZ
3354 * the target period becomes:
3357 * period = -------------------
3358 * @nsec * sample_freq
3363 * Reduce accuracy by one bit such that @a and @b converge
3364 * to a similar magnitude.
3366 #define REDUCE_FLS(a, b) \
3368 if (a##_fls > b##_fls) { \
3378 * Reduce accuracy until either term fits in a u64, then proceed with
3379 * the other, so that finally we can do a u64/u64 division.
3381 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3382 REDUCE_FLS(nsec, frequency);
3383 REDUCE_FLS(sec, count);
3386 if (count_fls + sec_fls > 64) {
3387 divisor = nsec * frequency;
3389 while (count_fls + sec_fls > 64) {
3390 REDUCE_FLS(count, sec);
3394 dividend = count * sec;
3396 dividend = count * sec;
3398 while (nsec_fls + frequency_fls > 64) {
3399 REDUCE_FLS(nsec, frequency);
3403 divisor = nsec * frequency;
3409 return div64_u64(dividend, divisor);
3412 static DEFINE_PER_CPU(int, perf_throttled_count);
3413 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3415 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3417 struct hw_perf_event *hwc = &event->hw;
3418 s64 period, sample_period;
3421 period = perf_calculate_period(event, nsec, count);
3423 delta = (s64)(period - hwc->sample_period);
3424 delta = (delta + 7) / 8; /* low pass filter */
3426 sample_period = hwc->sample_period + delta;
3431 hwc->sample_period = sample_period;
3433 if (local64_read(&hwc->period_left) > 8*sample_period) {
3435 event->pmu->stop(event, PERF_EF_UPDATE);
3437 local64_set(&hwc->period_left, 0);
3440 event->pmu->start(event, PERF_EF_RELOAD);
3445 * combine freq adjustment with unthrottling to avoid two passes over the
3446 * events. At the same time, make sure, having freq events does not change
3447 * the rate of unthrottling as that would introduce bias.
3449 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3452 struct perf_event *event;
3453 struct hw_perf_event *hwc;
3454 u64 now, period = TICK_NSEC;
3458 * only need to iterate over all events iff:
3459 * - context have events in frequency mode (needs freq adjust)
3460 * - there are events to unthrottle on this cpu
3462 if (!(ctx->nr_freq || needs_unthr))
3465 raw_spin_lock(&ctx->lock);
3466 perf_pmu_disable(ctx->pmu);
3468 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3469 if (event->state != PERF_EVENT_STATE_ACTIVE)
3472 if (!event_filter_match(event))
3475 perf_pmu_disable(event->pmu);
3479 if (hwc->interrupts == MAX_INTERRUPTS) {
3480 hwc->interrupts = 0;
3481 perf_log_throttle(event, 1);
3482 event->pmu->start(event, 0);
3485 if (!event->attr.freq || !event->attr.sample_freq)
3489 * stop the event and update event->count
3491 event->pmu->stop(event, PERF_EF_UPDATE);
3493 now = local64_read(&event->count);
3494 delta = now - hwc->freq_count_stamp;
3495 hwc->freq_count_stamp = now;
3499 * reload only if value has changed
3500 * we have stopped the event so tell that
3501 * to perf_adjust_period() to avoid stopping it
3505 perf_adjust_period(event, period, delta, false);
3507 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3509 perf_pmu_enable(event->pmu);
3512 perf_pmu_enable(ctx->pmu);
3513 raw_spin_unlock(&ctx->lock);
3517 * Round-robin a context's events:
3519 static void rotate_ctx(struct perf_event_context *ctx)
3522 * Rotate the first entry last of non-pinned groups. Rotation might be
3523 * disabled by the inheritance code.
3525 if (!ctx->rotate_disable)
3526 list_rotate_left(&ctx->flexible_groups);
3529 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3531 struct perf_event_context *ctx = NULL;
3534 if (cpuctx->ctx.nr_events) {
3535 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3539 ctx = cpuctx->task_ctx;
3540 if (ctx && ctx->nr_events) {
3541 if (ctx->nr_events != ctx->nr_active)
3548 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3549 perf_pmu_disable(cpuctx->ctx.pmu);
3551 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3553 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3555 rotate_ctx(&cpuctx->ctx);
3559 perf_event_sched_in(cpuctx, ctx, current);
3561 perf_pmu_enable(cpuctx->ctx.pmu);
3562 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3568 void perf_event_task_tick(void)
3570 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3571 struct perf_event_context *ctx, *tmp;
3574 WARN_ON(!irqs_disabled());
3576 __this_cpu_inc(perf_throttled_seq);
3577 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3578 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3580 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3581 perf_adjust_freq_unthr_context(ctx, throttled);
3584 static int event_enable_on_exec(struct perf_event *event,
3585 struct perf_event_context *ctx)
3587 if (!event->attr.enable_on_exec)
3590 event->attr.enable_on_exec = 0;
3591 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3594 __perf_event_mark_enabled(event);
3600 * Enable all of a task's events that have been marked enable-on-exec.
3601 * This expects task == current.
3603 static void perf_event_enable_on_exec(int ctxn)
3605 struct perf_event_context *ctx, *clone_ctx = NULL;
3606 enum event_type_t event_type = 0;
3607 struct perf_cpu_context *cpuctx;
3608 struct perf_event *event;
3609 unsigned long flags;
3612 local_irq_save(flags);
3613 ctx = current->perf_event_ctxp[ctxn];
3614 if (!ctx || !ctx->nr_events)
3617 cpuctx = __get_cpu_context(ctx);
3618 perf_ctx_lock(cpuctx, ctx);
3619 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3620 list_for_each_entry(event, &ctx->event_list, event_entry) {
3621 enabled |= event_enable_on_exec(event, ctx);
3622 event_type |= get_event_type(event);
3626 * Unclone and reschedule this context if we enabled any event.
3629 clone_ctx = unclone_ctx(ctx);
3630 ctx_resched(cpuctx, ctx, event_type);
3632 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3634 perf_ctx_unlock(cpuctx, ctx);
3637 local_irq_restore(flags);
3643 struct perf_read_data {
3644 struct perf_event *event;
3649 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3651 u16 local_pkg, event_pkg;
3653 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3654 int local_cpu = smp_processor_id();
3656 event_pkg = topology_physical_package_id(event_cpu);
3657 local_pkg = topology_physical_package_id(local_cpu);
3659 if (event_pkg == local_pkg)
3667 * Cross CPU call to read the hardware event
3669 static void __perf_event_read(void *info)
3671 struct perf_read_data *data = info;
3672 struct perf_event *sub, *event = data->event;
3673 struct perf_event_context *ctx = event->ctx;
3674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3675 struct pmu *pmu = event->pmu;
3678 * If this is a task context, we need to check whether it is
3679 * the current task context of this cpu. If not it has been
3680 * scheduled out before the smp call arrived. In that case
3681 * event->count would have been updated to a recent sample
3682 * when the event was scheduled out.
3684 if (ctx->task && cpuctx->task_ctx != ctx)
3687 raw_spin_lock(&ctx->lock);
3688 if (ctx->is_active) {
3689 update_context_time(ctx);
3690 update_cgrp_time_from_event(event);
3693 update_event_times(event);
3694 if (event->state != PERF_EVENT_STATE_ACTIVE)
3703 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3707 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3708 update_event_times(sub);
3709 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3711 * Use sibling's PMU rather than @event's since
3712 * sibling could be on different (eg: software) PMU.
3714 sub->pmu->read(sub);
3718 data->ret = pmu->commit_txn(pmu);
3721 raw_spin_unlock(&ctx->lock);
3724 static inline u64 perf_event_count(struct perf_event *event)
3726 return local64_read(&event->count) + atomic64_read(&event->child_count);
3730 * NMI-safe method to read a local event, that is an event that
3732 * - either for the current task, or for this CPU
3733 * - does not have inherit set, for inherited task events
3734 * will not be local and we cannot read them atomically
3735 * - must not have a pmu::count method
3737 int perf_event_read_local(struct perf_event *event, u64 *value)
3739 unsigned long flags;
3743 * Disabling interrupts avoids all counter scheduling (context
3744 * switches, timer based rotation and IPIs).
3746 local_irq_save(flags);
3749 * It must not be an event with inherit set, we cannot read
3750 * all child counters from atomic context.
3752 if (event->attr.inherit) {
3757 /* If this is a per-task event, it must be for current */
3758 if ((event->attach_state & PERF_ATTACH_TASK) &&
3759 event->hw.target != current) {
3764 /* If this is a per-CPU event, it must be for this CPU */
3765 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3766 event->cpu != smp_processor_id()) {
3771 /* If this is a pinned event it must be running on this CPU */
3772 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3778 * If the event is currently on this CPU, its either a per-task event,
3779 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3782 if (event->oncpu == smp_processor_id())
3783 event->pmu->read(event);
3785 *value = local64_read(&event->count);
3787 local_irq_restore(flags);
3792 static int perf_event_read(struct perf_event *event, bool group)
3794 int event_cpu, ret = 0;
3797 * If event is enabled and currently active on a CPU, update the
3798 * value in the event structure:
3800 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3801 struct perf_read_data data = {
3807 event_cpu = READ_ONCE(event->oncpu);
3808 if ((unsigned)event_cpu >= nr_cpu_ids)
3812 event_cpu = __perf_event_read_cpu(event, event_cpu);
3815 * Purposely ignore the smp_call_function_single() return
3818 * If event_cpu isn't a valid CPU it means the event got
3819 * scheduled out and that will have updated the event count.
3821 * Therefore, either way, we'll have an up-to-date event count
3824 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3827 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3828 struct perf_event_context *ctx = event->ctx;
3829 unsigned long flags;
3831 raw_spin_lock_irqsave(&ctx->lock, flags);
3833 * may read while context is not active
3834 * (e.g., thread is blocked), in that case
3835 * we cannot update context time
3837 if (ctx->is_active) {
3838 update_context_time(ctx);
3839 update_cgrp_time_from_event(event);
3842 update_group_times(event);
3844 update_event_times(event);
3845 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3852 * Initialize the perf_event context in a task_struct:
3854 static void __perf_event_init_context(struct perf_event_context *ctx)
3856 raw_spin_lock_init(&ctx->lock);
3857 mutex_init(&ctx->mutex);
3858 INIT_LIST_HEAD(&ctx->active_ctx_list);
3859 INIT_LIST_HEAD(&ctx->pinned_groups);
3860 INIT_LIST_HEAD(&ctx->flexible_groups);
3861 INIT_LIST_HEAD(&ctx->event_list);
3862 atomic_set(&ctx->refcount, 1);
3865 static struct perf_event_context *
3866 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3868 struct perf_event_context *ctx;
3870 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3874 __perf_event_init_context(ctx);
3877 get_task_struct(task);
3884 static struct task_struct *
3885 find_lively_task_by_vpid(pid_t vpid)
3887 struct task_struct *task;
3893 task = find_task_by_vpid(vpid);
3895 get_task_struct(task);
3899 return ERR_PTR(-ESRCH);
3905 * Returns a matching context with refcount and pincount.
3907 static struct perf_event_context *
3908 find_get_context(struct pmu *pmu, struct task_struct *task,
3909 struct perf_event *event)
3911 struct perf_event_context *ctx, *clone_ctx = NULL;
3912 struct perf_cpu_context *cpuctx;
3913 void *task_ctx_data = NULL;
3914 unsigned long flags;
3916 int cpu = event->cpu;
3919 /* Must be root to operate on a CPU event: */
3920 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3921 return ERR_PTR(-EACCES);
3923 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3926 raw_spin_lock_irqsave(&ctx->lock, flags);
3928 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3934 ctxn = pmu->task_ctx_nr;
3938 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3939 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3940 if (!task_ctx_data) {
3947 ctx = perf_lock_task_context(task, ctxn, &flags);
3949 clone_ctx = unclone_ctx(ctx);
3952 if (task_ctx_data && !ctx->task_ctx_data) {
3953 ctx->task_ctx_data = task_ctx_data;
3954 task_ctx_data = NULL;
3956 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3961 ctx = alloc_perf_context(pmu, task);
3966 if (task_ctx_data) {
3967 ctx->task_ctx_data = task_ctx_data;
3968 task_ctx_data = NULL;
3972 mutex_lock(&task->perf_event_mutex);
3974 * If it has already passed perf_event_exit_task().
3975 * we must see PF_EXITING, it takes this mutex too.
3977 if (task->flags & PF_EXITING)
3979 else if (task->perf_event_ctxp[ctxn])
3984 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3986 mutex_unlock(&task->perf_event_mutex);
3988 if (unlikely(err)) {
3997 kfree(task_ctx_data);
4001 kfree(task_ctx_data);
4002 return ERR_PTR(err);
4005 static void perf_event_free_filter(struct perf_event *event);
4006 static void perf_event_free_bpf_prog(struct perf_event *event);
4008 static void free_event_rcu(struct rcu_head *head)
4010 struct perf_event *event;
4012 event = container_of(head, struct perf_event, rcu_head);
4014 put_pid_ns(event->ns);
4015 perf_event_free_filter(event);
4019 static void ring_buffer_attach(struct perf_event *event,
4020 struct ring_buffer *rb);
4022 static void detach_sb_event(struct perf_event *event)
4024 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4026 raw_spin_lock(&pel->lock);
4027 list_del_rcu(&event->sb_list);
4028 raw_spin_unlock(&pel->lock);
4031 static bool is_sb_event(struct perf_event *event)
4033 struct perf_event_attr *attr = &event->attr;
4038 if (event->attach_state & PERF_ATTACH_TASK)
4041 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4042 attr->comm || attr->comm_exec ||
4044 attr->context_switch)
4049 static void unaccount_pmu_sb_event(struct perf_event *event)
4051 if (is_sb_event(event))
4052 detach_sb_event(event);
4055 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4060 if (is_cgroup_event(event))
4061 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4064 #ifdef CONFIG_NO_HZ_FULL
4065 static DEFINE_SPINLOCK(nr_freq_lock);
4068 static void unaccount_freq_event_nohz(void)
4070 #ifdef CONFIG_NO_HZ_FULL
4071 spin_lock(&nr_freq_lock);
4072 if (atomic_dec_and_test(&nr_freq_events))
4073 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4074 spin_unlock(&nr_freq_lock);
4078 static void unaccount_freq_event(void)
4080 if (tick_nohz_full_enabled())
4081 unaccount_freq_event_nohz();
4083 atomic_dec(&nr_freq_events);
4086 static void unaccount_event(struct perf_event *event)
4093 if (event->attach_state & PERF_ATTACH_TASK)
4095 if (event->attr.mmap || event->attr.mmap_data)
4096 atomic_dec(&nr_mmap_events);
4097 if (event->attr.comm)
4098 atomic_dec(&nr_comm_events);
4099 if (event->attr.namespaces)
4100 atomic_dec(&nr_namespaces_events);
4101 if (event->attr.task)
4102 atomic_dec(&nr_task_events);
4103 if (event->attr.freq)
4104 unaccount_freq_event();
4105 if (event->attr.context_switch) {
4107 atomic_dec(&nr_switch_events);
4109 if (is_cgroup_event(event))
4111 if (has_branch_stack(event))
4115 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4116 schedule_delayed_work(&perf_sched_work, HZ);
4119 unaccount_event_cpu(event, event->cpu);
4121 unaccount_pmu_sb_event(event);
4124 static void perf_sched_delayed(struct work_struct *work)
4126 mutex_lock(&perf_sched_mutex);
4127 if (atomic_dec_and_test(&perf_sched_count))
4128 static_branch_disable(&perf_sched_events);
4129 mutex_unlock(&perf_sched_mutex);
4133 * The following implement mutual exclusion of events on "exclusive" pmus
4134 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4135 * at a time, so we disallow creating events that might conflict, namely:
4137 * 1) cpu-wide events in the presence of per-task events,
4138 * 2) per-task events in the presence of cpu-wide events,
4139 * 3) two matching events on the same context.
4141 * The former two cases are handled in the allocation path (perf_event_alloc(),
4142 * _free_event()), the latter -- before the first perf_install_in_context().
4144 static int exclusive_event_init(struct perf_event *event)
4146 struct pmu *pmu = event->pmu;
4148 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4152 * Prevent co-existence of per-task and cpu-wide events on the
4153 * same exclusive pmu.
4155 * Negative pmu::exclusive_cnt means there are cpu-wide
4156 * events on this "exclusive" pmu, positive means there are
4159 * Since this is called in perf_event_alloc() path, event::ctx
4160 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4161 * to mean "per-task event", because unlike other attach states it
4162 * never gets cleared.
4164 if (event->attach_state & PERF_ATTACH_TASK) {
4165 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4168 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4175 static void exclusive_event_destroy(struct perf_event *event)
4177 struct pmu *pmu = event->pmu;
4179 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4182 /* see comment in exclusive_event_init() */
4183 if (event->attach_state & PERF_ATTACH_TASK)
4184 atomic_dec(&pmu->exclusive_cnt);
4186 atomic_inc(&pmu->exclusive_cnt);
4189 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4191 if ((e1->pmu == e2->pmu) &&
4192 (e1->cpu == e2->cpu ||
4199 /* Called under the same ctx::mutex as perf_install_in_context() */
4200 static bool exclusive_event_installable(struct perf_event *event,
4201 struct perf_event_context *ctx)
4203 struct perf_event *iter_event;
4204 struct pmu *pmu = event->pmu;
4206 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4209 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4210 if (exclusive_event_match(iter_event, event))
4217 static void perf_addr_filters_splice(struct perf_event *event,
4218 struct list_head *head);
4220 static void _free_event(struct perf_event *event)
4222 irq_work_sync(&event->pending);
4224 unaccount_event(event);
4228 * Can happen when we close an event with re-directed output.
4230 * Since we have a 0 refcount, perf_mmap_close() will skip
4231 * over us; possibly making our ring_buffer_put() the last.
4233 mutex_lock(&event->mmap_mutex);
4234 ring_buffer_attach(event, NULL);
4235 mutex_unlock(&event->mmap_mutex);
4238 if (is_cgroup_event(event))
4239 perf_detach_cgroup(event);
4241 if (!event->parent) {
4242 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4243 put_callchain_buffers();
4246 perf_event_free_bpf_prog(event);
4247 perf_addr_filters_splice(event, NULL);
4248 kfree(event->addr_filters_offs);
4251 event->destroy(event);
4254 put_ctx(event->ctx);
4256 if (event->hw.target)
4257 put_task_struct(event->hw.target);
4259 exclusive_event_destroy(event);
4260 module_put(event->pmu->module);
4262 call_rcu(&event->rcu_head, free_event_rcu);
4266 * Used to free events which have a known refcount of 1, such as in error paths
4267 * where the event isn't exposed yet and inherited events.
4269 static void free_event(struct perf_event *event)
4271 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4272 "unexpected event refcount: %ld; ptr=%p\n",
4273 atomic_long_read(&event->refcount), event)) {
4274 /* leak to avoid use-after-free */
4282 * Remove user event from the owner task.
4284 static void perf_remove_from_owner(struct perf_event *event)
4286 struct task_struct *owner;
4290 * Matches the smp_store_release() in perf_event_exit_task(). If we
4291 * observe !owner it means the list deletion is complete and we can
4292 * indeed free this event, otherwise we need to serialize on
4293 * owner->perf_event_mutex.
4295 owner = READ_ONCE(event->owner);
4298 * Since delayed_put_task_struct() also drops the last
4299 * task reference we can safely take a new reference
4300 * while holding the rcu_read_lock().
4302 get_task_struct(owner);
4308 * If we're here through perf_event_exit_task() we're already
4309 * holding ctx->mutex which would be an inversion wrt. the
4310 * normal lock order.
4312 * However we can safely take this lock because its the child
4315 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4318 * We have to re-check the event->owner field, if it is cleared
4319 * we raced with perf_event_exit_task(), acquiring the mutex
4320 * ensured they're done, and we can proceed with freeing the
4324 list_del_init(&event->owner_entry);
4325 smp_store_release(&event->owner, NULL);
4327 mutex_unlock(&owner->perf_event_mutex);
4328 put_task_struct(owner);
4332 static void put_event(struct perf_event *event)
4334 if (!atomic_long_dec_and_test(&event->refcount))
4341 * Kill an event dead; while event:refcount will preserve the event
4342 * object, it will not preserve its functionality. Once the last 'user'
4343 * gives up the object, we'll destroy the thing.
4345 int perf_event_release_kernel(struct perf_event *event)
4347 struct perf_event_context *ctx = event->ctx;
4348 struct perf_event *child, *tmp;
4351 * If we got here through err_file: fput(event_file); we will not have
4352 * attached to a context yet.
4355 WARN_ON_ONCE(event->attach_state &
4356 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4360 if (!is_kernel_event(event))
4361 perf_remove_from_owner(event);
4363 ctx = perf_event_ctx_lock(event);
4364 WARN_ON_ONCE(ctx->parent_ctx);
4365 perf_remove_from_context(event, DETACH_GROUP);
4367 raw_spin_lock_irq(&ctx->lock);
4369 * Mark this event as STATE_DEAD, there is no external reference to it
4372 * Anybody acquiring event->child_mutex after the below loop _must_
4373 * also see this, most importantly inherit_event() which will avoid
4374 * placing more children on the list.
4376 * Thus this guarantees that we will in fact observe and kill _ALL_
4379 event->state = PERF_EVENT_STATE_DEAD;
4380 raw_spin_unlock_irq(&ctx->lock);
4382 perf_event_ctx_unlock(event, ctx);
4385 mutex_lock(&event->child_mutex);
4386 list_for_each_entry(child, &event->child_list, child_list) {
4389 * Cannot change, child events are not migrated, see the
4390 * comment with perf_event_ctx_lock_nested().
4392 ctx = READ_ONCE(child->ctx);
4394 * Since child_mutex nests inside ctx::mutex, we must jump
4395 * through hoops. We start by grabbing a reference on the ctx.
4397 * Since the event cannot get freed while we hold the
4398 * child_mutex, the context must also exist and have a !0
4404 * Now that we have a ctx ref, we can drop child_mutex, and
4405 * acquire ctx::mutex without fear of it going away. Then we
4406 * can re-acquire child_mutex.
4408 mutex_unlock(&event->child_mutex);
4409 mutex_lock(&ctx->mutex);
4410 mutex_lock(&event->child_mutex);
4413 * Now that we hold ctx::mutex and child_mutex, revalidate our
4414 * state, if child is still the first entry, it didn't get freed
4415 * and we can continue doing so.
4417 tmp = list_first_entry_or_null(&event->child_list,
4418 struct perf_event, child_list);
4420 perf_remove_from_context(child, DETACH_GROUP);
4421 list_del(&child->child_list);
4424 * This matches the refcount bump in inherit_event();
4425 * this can't be the last reference.
4430 mutex_unlock(&event->child_mutex);
4431 mutex_unlock(&ctx->mutex);
4435 mutex_unlock(&event->child_mutex);
4438 put_event(event); /* Must be the 'last' reference */
4441 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4444 * Called when the last reference to the file is gone.
4446 static int perf_release(struct inode *inode, struct file *file)
4448 perf_event_release_kernel(file->private_data);
4452 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4454 struct perf_event *child;
4460 mutex_lock(&event->child_mutex);
4462 (void)perf_event_read(event, false);
4463 total += perf_event_count(event);
4465 *enabled += event->total_time_enabled +
4466 atomic64_read(&event->child_total_time_enabled);
4467 *running += event->total_time_running +
4468 atomic64_read(&event->child_total_time_running);
4470 list_for_each_entry(child, &event->child_list, child_list) {
4471 (void)perf_event_read(child, false);
4472 total += perf_event_count(child);
4473 *enabled += child->total_time_enabled;
4474 *running += child->total_time_running;
4476 mutex_unlock(&event->child_mutex);
4480 EXPORT_SYMBOL_GPL(perf_event_read_value);
4482 static int __perf_read_group_add(struct perf_event *leader,
4483 u64 read_format, u64 *values)
4485 struct perf_event_context *ctx = leader->ctx;
4486 struct perf_event *sub;
4487 unsigned long flags;
4488 int n = 1; /* skip @nr */
4491 ret = perf_event_read(leader, true);
4495 raw_spin_lock_irqsave(&ctx->lock, flags);
4498 * Since we co-schedule groups, {enabled,running} times of siblings
4499 * will be identical to those of the leader, so we only publish one
4502 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4503 values[n++] += leader->total_time_enabled +
4504 atomic64_read(&leader->child_total_time_enabled);
4507 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4508 values[n++] += leader->total_time_running +
4509 atomic64_read(&leader->child_total_time_running);
4513 * Write {count,id} tuples for every sibling.
4515 values[n++] += perf_event_count(leader);
4516 if (read_format & PERF_FORMAT_ID)
4517 values[n++] = primary_event_id(leader);
4519 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4520 values[n++] += perf_event_count(sub);
4521 if (read_format & PERF_FORMAT_ID)
4522 values[n++] = primary_event_id(sub);
4525 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4529 static int perf_read_group(struct perf_event *event,
4530 u64 read_format, char __user *buf)
4532 struct perf_event *leader = event->group_leader, *child;
4533 struct perf_event_context *ctx = leader->ctx;
4537 lockdep_assert_held(&ctx->mutex);
4539 values = kzalloc(event->read_size, GFP_KERNEL);
4543 values[0] = 1 + leader->nr_siblings;
4546 * By locking the child_mutex of the leader we effectively
4547 * lock the child list of all siblings.. XXX explain how.
4549 mutex_lock(&leader->child_mutex);
4551 ret = __perf_read_group_add(leader, read_format, values);
4555 list_for_each_entry(child, &leader->child_list, child_list) {
4556 ret = __perf_read_group_add(child, read_format, values);
4561 mutex_unlock(&leader->child_mutex);
4563 ret = event->read_size;
4564 if (copy_to_user(buf, values, event->read_size))
4569 mutex_unlock(&leader->child_mutex);
4575 static int perf_read_one(struct perf_event *event,
4576 u64 read_format, char __user *buf)
4578 u64 enabled, running;
4582 values[n++] = perf_event_read_value(event, &enabled, &running);
4583 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4584 values[n++] = enabled;
4585 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4586 values[n++] = running;
4587 if (read_format & PERF_FORMAT_ID)
4588 values[n++] = primary_event_id(event);
4590 if (copy_to_user(buf, values, n * sizeof(u64)))
4593 return n * sizeof(u64);
4596 static bool is_event_hup(struct perf_event *event)
4600 if (event->state > PERF_EVENT_STATE_EXIT)
4603 mutex_lock(&event->child_mutex);
4604 no_children = list_empty(&event->child_list);
4605 mutex_unlock(&event->child_mutex);
4610 * Read the performance event - simple non blocking version for now
4613 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4615 u64 read_format = event->attr.read_format;
4619 * Return end-of-file for a read on a event that is in
4620 * error state (i.e. because it was pinned but it couldn't be
4621 * scheduled on to the CPU at some point).
4623 if (event->state == PERF_EVENT_STATE_ERROR)
4626 if (count < event->read_size)
4629 WARN_ON_ONCE(event->ctx->parent_ctx);
4630 if (read_format & PERF_FORMAT_GROUP)
4631 ret = perf_read_group(event, read_format, buf);
4633 ret = perf_read_one(event, read_format, buf);
4639 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4641 struct perf_event *event = file->private_data;
4642 struct perf_event_context *ctx;
4645 ctx = perf_event_ctx_lock(event);
4646 ret = __perf_read(event, buf, count);
4647 perf_event_ctx_unlock(event, ctx);
4652 static unsigned int perf_poll(struct file *file, poll_table *wait)
4654 struct perf_event *event = file->private_data;
4655 struct ring_buffer *rb;
4656 unsigned int events = POLLHUP;
4658 poll_wait(file, &event->waitq, wait);
4660 if (is_event_hup(event))
4664 * Pin the event->rb by taking event->mmap_mutex; otherwise
4665 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4667 mutex_lock(&event->mmap_mutex);
4670 events = atomic_xchg(&rb->poll, 0);
4671 mutex_unlock(&event->mmap_mutex);
4675 static void _perf_event_reset(struct perf_event *event)
4677 (void)perf_event_read(event, false);
4678 local64_set(&event->count, 0);
4679 perf_event_update_userpage(event);
4683 * Holding the top-level event's child_mutex means that any
4684 * descendant process that has inherited this event will block
4685 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4686 * task existence requirements of perf_event_enable/disable.
4688 static void perf_event_for_each_child(struct perf_event *event,
4689 void (*func)(struct perf_event *))
4691 struct perf_event *child;
4693 WARN_ON_ONCE(event->ctx->parent_ctx);
4695 mutex_lock(&event->child_mutex);
4697 list_for_each_entry(child, &event->child_list, child_list)
4699 mutex_unlock(&event->child_mutex);
4702 static void perf_event_for_each(struct perf_event *event,
4703 void (*func)(struct perf_event *))
4705 struct perf_event_context *ctx = event->ctx;
4706 struct perf_event *sibling;
4708 lockdep_assert_held(&ctx->mutex);
4710 event = event->group_leader;
4712 perf_event_for_each_child(event, func);
4713 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4714 perf_event_for_each_child(sibling, func);
4717 static void __perf_event_period(struct perf_event *event,
4718 struct perf_cpu_context *cpuctx,
4719 struct perf_event_context *ctx,
4722 u64 value = *((u64 *)info);
4725 if (event->attr.freq) {
4726 event->attr.sample_freq = value;
4728 event->attr.sample_period = value;
4729 event->hw.sample_period = value;
4732 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4734 perf_pmu_disable(ctx->pmu);
4736 * We could be throttled; unthrottle now to avoid the tick
4737 * trying to unthrottle while we already re-started the event.
4739 if (event->hw.interrupts == MAX_INTERRUPTS) {
4740 event->hw.interrupts = 0;
4741 perf_log_throttle(event, 1);
4743 event->pmu->stop(event, PERF_EF_UPDATE);
4746 local64_set(&event->hw.period_left, 0);
4749 event->pmu->start(event, PERF_EF_RELOAD);
4750 perf_pmu_enable(ctx->pmu);
4754 static int perf_event_check_period(struct perf_event *event, u64 value)
4756 return event->pmu->check_period(event, value);
4759 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4763 if (!is_sampling_event(event))
4766 if (copy_from_user(&value, arg, sizeof(value)))
4772 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4775 if (perf_event_check_period(event, value))
4778 if (!event->attr.freq && (value & (1ULL << 63)))
4781 event_function_call(event, __perf_event_period, &value);
4786 static const struct file_operations perf_fops;
4788 static inline int perf_fget_light(int fd, struct fd *p)
4790 struct fd f = fdget(fd);
4794 if (f.file->f_op != &perf_fops) {
4802 static int perf_event_set_output(struct perf_event *event,
4803 struct perf_event *output_event);
4804 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4805 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4807 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4809 void (*func)(struct perf_event *);
4813 case PERF_EVENT_IOC_ENABLE:
4814 func = _perf_event_enable;
4816 case PERF_EVENT_IOC_DISABLE:
4817 func = _perf_event_disable;
4819 case PERF_EVENT_IOC_RESET:
4820 func = _perf_event_reset;
4823 case PERF_EVENT_IOC_REFRESH:
4824 return _perf_event_refresh(event, arg);
4826 case PERF_EVENT_IOC_PERIOD:
4827 return perf_event_period(event, (u64 __user *)arg);
4829 case PERF_EVENT_IOC_ID:
4831 u64 id = primary_event_id(event);
4833 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4838 case PERF_EVENT_IOC_SET_OUTPUT:
4842 struct perf_event *output_event;
4844 ret = perf_fget_light(arg, &output);
4847 output_event = output.file->private_data;
4848 ret = perf_event_set_output(event, output_event);
4851 ret = perf_event_set_output(event, NULL);
4856 case PERF_EVENT_IOC_SET_FILTER:
4857 return perf_event_set_filter(event, (void __user *)arg);
4859 case PERF_EVENT_IOC_SET_BPF:
4860 return perf_event_set_bpf_prog(event, arg);
4862 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4863 struct ring_buffer *rb;
4866 rb = rcu_dereference(event->rb);
4867 if (!rb || !rb->nr_pages) {
4871 rb_toggle_paused(rb, !!arg);
4879 if (flags & PERF_IOC_FLAG_GROUP)
4880 perf_event_for_each(event, func);
4882 perf_event_for_each_child(event, func);
4887 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4889 struct perf_event *event = file->private_data;
4890 struct perf_event_context *ctx;
4893 ctx = perf_event_ctx_lock(event);
4894 ret = _perf_ioctl(event, cmd, arg);
4895 perf_event_ctx_unlock(event, ctx);
4900 #ifdef CONFIG_COMPAT
4901 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4904 switch (_IOC_NR(cmd)) {
4905 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4906 case _IOC_NR(PERF_EVENT_IOC_ID):
4907 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4908 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4909 cmd &= ~IOCSIZE_MASK;
4910 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4914 return perf_ioctl(file, cmd, arg);
4917 # define perf_compat_ioctl NULL
4920 int perf_event_task_enable(void)
4922 struct perf_event_context *ctx;
4923 struct perf_event *event;
4925 mutex_lock(¤t->perf_event_mutex);
4926 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4927 ctx = perf_event_ctx_lock(event);
4928 perf_event_for_each_child(event, _perf_event_enable);
4929 perf_event_ctx_unlock(event, ctx);
4931 mutex_unlock(¤t->perf_event_mutex);
4936 int perf_event_task_disable(void)
4938 struct perf_event_context *ctx;
4939 struct perf_event *event;
4941 mutex_lock(¤t->perf_event_mutex);
4942 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4943 ctx = perf_event_ctx_lock(event);
4944 perf_event_for_each_child(event, _perf_event_disable);
4945 perf_event_ctx_unlock(event, ctx);
4947 mutex_unlock(¤t->perf_event_mutex);
4952 static int perf_event_index(struct perf_event *event)
4954 if (event->hw.state & PERF_HES_STOPPED)
4957 if (event->state != PERF_EVENT_STATE_ACTIVE)
4960 return event->pmu->event_idx(event);
4963 static void calc_timer_values(struct perf_event *event,
4970 *now = perf_clock();
4971 ctx_time = event->shadow_ctx_time + *now;
4972 *enabled = ctx_time - event->tstamp_enabled;
4973 *running = ctx_time - event->tstamp_running;
4976 static void perf_event_init_userpage(struct perf_event *event)
4978 struct perf_event_mmap_page *userpg;
4979 struct ring_buffer *rb;
4982 rb = rcu_dereference(event->rb);
4986 userpg = rb->user_page;
4988 /* Allow new userspace to detect that bit 0 is deprecated */
4989 userpg->cap_bit0_is_deprecated = 1;
4990 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4991 userpg->data_offset = PAGE_SIZE;
4992 userpg->data_size = perf_data_size(rb);
4998 void __weak arch_perf_update_userpage(
4999 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5004 * Callers need to ensure there can be no nesting of this function, otherwise
5005 * the seqlock logic goes bad. We can not serialize this because the arch
5006 * code calls this from NMI context.
5008 void perf_event_update_userpage(struct perf_event *event)
5010 struct perf_event_mmap_page *userpg;
5011 struct ring_buffer *rb;
5012 u64 enabled, running, now;
5015 rb = rcu_dereference(event->rb);
5020 * compute total_time_enabled, total_time_running
5021 * based on snapshot values taken when the event
5022 * was last scheduled in.
5024 * we cannot simply called update_context_time()
5025 * because of locking issue as we can be called in
5028 calc_timer_values(event, &now, &enabled, &running);
5030 userpg = rb->user_page;
5032 * Disable preemption so as to not let the corresponding user-space
5033 * spin too long if we get preempted.
5038 userpg->index = perf_event_index(event);
5039 userpg->offset = perf_event_count(event);
5041 userpg->offset -= local64_read(&event->hw.prev_count);
5043 userpg->time_enabled = enabled +
5044 atomic64_read(&event->child_total_time_enabled);
5046 userpg->time_running = running +
5047 atomic64_read(&event->child_total_time_running);
5049 arch_perf_update_userpage(event, userpg, now);
5058 static int perf_mmap_fault(struct vm_fault *vmf)
5060 struct perf_event *event = vmf->vma->vm_file->private_data;
5061 struct ring_buffer *rb;
5062 int ret = VM_FAULT_SIGBUS;
5064 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5065 if (vmf->pgoff == 0)
5071 rb = rcu_dereference(event->rb);
5075 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5078 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5082 get_page(vmf->page);
5083 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5084 vmf->page->index = vmf->pgoff;
5093 static void ring_buffer_attach(struct perf_event *event,
5094 struct ring_buffer *rb)
5096 struct ring_buffer *old_rb = NULL;
5097 unsigned long flags;
5101 * Should be impossible, we set this when removing
5102 * event->rb_entry and wait/clear when adding event->rb_entry.
5104 WARN_ON_ONCE(event->rcu_pending);
5107 spin_lock_irqsave(&old_rb->event_lock, flags);
5108 list_del_rcu(&event->rb_entry);
5109 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5111 event->rcu_batches = get_state_synchronize_rcu();
5112 event->rcu_pending = 1;
5116 if (event->rcu_pending) {
5117 cond_synchronize_rcu(event->rcu_batches);
5118 event->rcu_pending = 0;
5121 spin_lock_irqsave(&rb->event_lock, flags);
5122 list_add_rcu(&event->rb_entry, &rb->event_list);
5123 spin_unlock_irqrestore(&rb->event_lock, flags);
5127 * Avoid racing with perf_mmap_close(AUX): stop the event
5128 * before swizzling the event::rb pointer; if it's getting
5129 * unmapped, its aux_mmap_count will be 0 and it won't
5130 * restart. See the comment in __perf_pmu_output_stop().
5132 * Data will inevitably be lost when set_output is done in
5133 * mid-air, but then again, whoever does it like this is
5134 * not in for the data anyway.
5137 perf_event_stop(event, 0);
5139 rcu_assign_pointer(event->rb, rb);
5142 ring_buffer_put(old_rb);
5144 * Since we detached before setting the new rb, so that we
5145 * could attach the new rb, we could have missed a wakeup.
5148 wake_up_all(&event->waitq);
5152 static void ring_buffer_wakeup(struct perf_event *event)
5154 struct ring_buffer *rb;
5157 rb = rcu_dereference(event->rb);
5159 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5160 wake_up_all(&event->waitq);
5165 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5167 struct ring_buffer *rb;
5170 rb = rcu_dereference(event->rb);
5172 if (!atomic_inc_not_zero(&rb->refcount))
5180 void ring_buffer_put(struct ring_buffer *rb)
5182 if (!atomic_dec_and_test(&rb->refcount))
5185 WARN_ON_ONCE(!list_empty(&rb->event_list));
5187 call_rcu(&rb->rcu_head, rb_free_rcu);
5190 static void perf_mmap_open(struct vm_area_struct *vma)
5192 struct perf_event *event = vma->vm_file->private_data;
5194 atomic_inc(&event->mmap_count);
5195 atomic_inc(&event->rb->mmap_count);
5198 atomic_inc(&event->rb->aux_mmap_count);
5200 if (event->pmu->event_mapped)
5201 event->pmu->event_mapped(event, vma->vm_mm);
5204 static void perf_pmu_output_stop(struct perf_event *event);
5207 * A buffer can be mmap()ed multiple times; either directly through the same
5208 * event, or through other events by use of perf_event_set_output().
5210 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5211 * the buffer here, where we still have a VM context. This means we need
5212 * to detach all events redirecting to us.
5214 static void perf_mmap_close(struct vm_area_struct *vma)
5216 struct perf_event *event = vma->vm_file->private_data;
5217 struct ring_buffer *rb = ring_buffer_get(event);
5218 struct user_struct *mmap_user = rb->mmap_user;
5219 int mmap_locked = rb->mmap_locked;
5220 unsigned long size = perf_data_size(rb);
5221 bool detach_rest = false;
5223 if (event->pmu->event_unmapped)
5224 event->pmu->event_unmapped(event, vma->vm_mm);
5227 * rb->aux_mmap_count will always drop before rb->mmap_count and
5228 * event->mmap_count, so it is ok to use event->mmap_mutex to
5229 * serialize with perf_mmap here.
5231 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5232 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5234 * Stop all AUX events that are writing to this buffer,
5235 * so that we can free its AUX pages and corresponding PMU
5236 * data. Note that after rb::aux_mmap_count dropped to zero,
5237 * they won't start any more (see perf_aux_output_begin()).
5239 perf_pmu_output_stop(event);
5241 /* now it's safe to free the pages */
5242 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5243 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5245 /* this has to be the last one */
5247 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5249 mutex_unlock(&event->mmap_mutex);
5252 if (atomic_dec_and_test(&rb->mmap_count))
5255 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5258 ring_buffer_attach(event, NULL);
5259 mutex_unlock(&event->mmap_mutex);
5261 /* If there's still other mmap()s of this buffer, we're done. */
5266 * No other mmap()s, detach from all other events that might redirect
5267 * into the now unreachable buffer. Somewhat complicated by the
5268 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5272 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5273 if (!atomic_long_inc_not_zero(&event->refcount)) {
5275 * This event is en-route to free_event() which will
5276 * detach it and remove it from the list.
5282 mutex_lock(&event->mmap_mutex);
5284 * Check we didn't race with perf_event_set_output() which can
5285 * swizzle the rb from under us while we were waiting to
5286 * acquire mmap_mutex.
5288 * If we find a different rb; ignore this event, a next
5289 * iteration will no longer find it on the list. We have to
5290 * still restart the iteration to make sure we're not now
5291 * iterating the wrong list.
5293 if (event->rb == rb)
5294 ring_buffer_attach(event, NULL);
5296 mutex_unlock(&event->mmap_mutex);
5300 * Restart the iteration; either we're on the wrong list or
5301 * destroyed its integrity by doing a deletion.
5308 * It could be there's still a few 0-ref events on the list; they'll
5309 * get cleaned up by free_event() -- they'll also still have their
5310 * ref on the rb and will free it whenever they are done with it.
5312 * Aside from that, this buffer is 'fully' detached and unmapped,
5313 * undo the VM accounting.
5316 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5317 vma->vm_mm->pinned_vm -= mmap_locked;
5318 free_uid(mmap_user);
5321 ring_buffer_put(rb); /* could be last */
5324 static const struct vm_operations_struct perf_mmap_vmops = {
5325 .open = perf_mmap_open,
5326 .close = perf_mmap_close, /* non mergable */
5327 .fault = perf_mmap_fault,
5328 .page_mkwrite = perf_mmap_fault,
5331 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5333 struct perf_event *event = file->private_data;
5334 unsigned long user_locked, user_lock_limit;
5335 struct user_struct *user = current_user();
5336 unsigned long locked, lock_limit;
5337 struct ring_buffer *rb = NULL;
5338 unsigned long vma_size;
5339 unsigned long nr_pages;
5340 long user_extra = 0, extra = 0;
5341 int ret = 0, flags = 0;
5344 * Don't allow mmap() of inherited per-task counters. This would
5345 * create a performance issue due to all children writing to the
5348 if (event->cpu == -1 && event->attr.inherit)
5351 if (!(vma->vm_flags & VM_SHARED))
5354 vma_size = vma->vm_end - vma->vm_start;
5356 if (vma->vm_pgoff == 0) {
5357 nr_pages = (vma_size / PAGE_SIZE) - 1;
5360 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5361 * mapped, all subsequent mappings should have the same size
5362 * and offset. Must be above the normal perf buffer.
5364 u64 aux_offset, aux_size;
5369 nr_pages = vma_size / PAGE_SIZE;
5371 mutex_lock(&event->mmap_mutex);
5378 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5379 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5381 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5384 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5387 /* already mapped with a different offset */
5388 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5391 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5394 /* already mapped with a different size */
5395 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5398 if (!is_power_of_2(nr_pages))
5401 if (!atomic_inc_not_zero(&rb->mmap_count))
5404 if (rb_has_aux(rb)) {
5405 atomic_inc(&rb->aux_mmap_count);
5410 atomic_set(&rb->aux_mmap_count, 1);
5411 user_extra = nr_pages;
5417 * If we have rb pages ensure they're a power-of-two number, so we
5418 * can do bitmasks instead of modulo.
5420 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5423 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5426 WARN_ON_ONCE(event->ctx->parent_ctx);
5428 mutex_lock(&event->mmap_mutex);
5430 if (event->rb->nr_pages != nr_pages) {
5435 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5437 * Raced against perf_mmap_close(); remove the
5438 * event and try again.
5440 ring_buffer_attach(event, NULL);
5441 mutex_unlock(&event->mmap_mutex);
5448 user_extra = nr_pages + 1;
5451 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5454 * Increase the limit linearly with more CPUs:
5456 user_lock_limit *= num_online_cpus();
5458 user_locked = atomic_long_read(&user->locked_vm);
5461 * sysctl_perf_event_mlock may have changed, so that
5462 * user->locked_vm > user_lock_limit
5464 if (user_locked > user_lock_limit)
5465 user_locked = user_lock_limit;
5466 user_locked += user_extra;
5468 if (user_locked > user_lock_limit)
5469 extra = user_locked - user_lock_limit;
5471 lock_limit = rlimit(RLIMIT_MEMLOCK);
5472 lock_limit >>= PAGE_SHIFT;
5473 locked = vma->vm_mm->pinned_vm + extra;
5475 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5476 !capable(CAP_IPC_LOCK)) {
5481 WARN_ON(!rb && event->rb);
5483 if (vma->vm_flags & VM_WRITE)
5484 flags |= RING_BUFFER_WRITABLE;
5487 rb = rb_alloc(nr_pages,
5488 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5496 atomic_set(&rb->mmap_count, 1);
5497 rb->mmap_user = get_current_user();
5498 rb->mmap_locked = extra;
5500 ring_buffer_attach(event, rb);
5502 perf_event_init_userpage(event);
5503 perf_event_update_userpage(event);
5505 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5506 event->attr.aux_watermark, flags);
5508 rb->aux_mmap_locked = extra;
5513 atomic_long_add(user_extra, &user->locked_vm);
5514 vma->vm_mm->pinned_vm += extra;
5516 atomic_inc(&event->mmap_count);
5518 atomic_dec(&rb->mmap_count);
5521 mutex_unlock(&event->mmap_mutex);
5524 * Since pinned accounting is per vm we cannot allow fork() to copy our
5527 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5528 vma->vm_ops = &perf_mmap_vmops;
5530 if (event->pmu->event_mapped)
5531 event->pmu->event_mapped(event, vma->vm_mm);
5536 static int perf_fasync(int fd, struct file *filp, int on)
5538 struct inode *inode = file_inode(filp);
5539 struct perf_event *event = filp->private_data;
5543 retval = fasync_helper(fd, filp, on, &event->fasync);
5544 inode_unlock(inode);
5552 static const struct file_operations perf_fops = {
5553 .llseek = no_llseek,
5554 .release = perf_release,
5557 .unlocked_ioctl = perf_ioctl,
5558 .compat_ioctl = perf_compat_ioctl,
5560 .fasync = perf_fasync,
5566 * If there's data, ensure we set the poll() state and publish everything
5567 * to user-space before waking everybody up.
5570 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5572 /* only the parent has fasync state */
5574 event = event->parent;
5575 return &event->fasync;
5578 void perf_event_wakeup(struct perf_event *event)
5580 ring_buffer_wakeup(event);
5582 if (event->pending_kill) {
5583 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5584 event->pending_kill = 0;
5588 static void perf_pending_event(struct irq_work *entry)
5590 struct perf_event *event = container_of(entry,
5591 struct perf_event, pending);
5594 rctx = perf_swevent_get_recursion_context();
5596 * If we 'fail' here, that's OK, it means recursion is already disabled
5597 * and we won't recurse 'further'.
5600 if (event->pending_disable) {
5601 event->pending_disable = 0;
5602 perf_event_disable_local(event);
5605 if (event->pending_wakeup) {
5606 event->pending_wakeup = 0;
5607 perf_event_wakeup(event);
5611 perf_swevent_put_recursion_context(rctx);
5615 * We assume there is only KVM supporting the callbacks.
5616 * Later on, we might change it to a list if there is
5617 * another virtualization implementation supporting the callbacks.
5619 struct perf_guest_info_callbacks *perf_guest_cbs;
5621 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5623 perf_guest_cbs = cbs;
5626 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5628 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5630 perf_guest_cbs = NULL;
5633 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5636 perf_output_sample_regs(struct perf_output_handle *handle,
5637 struct pt_regs *regs, u64 mask)
5640 DECLARE_BITMAP(_mask, 64);
5642 bitmap_from_u64(_mask, mask);
5643 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5646 val = perf_reg_value(regs, bit);
5647 perf_output_put(handle, val);
5651 static void perf_sample_regs_user(struct perf_regs *regs_user,
5652 struct pt_regs *regs,
5653 struct pt_regs *regs_user_copy)
5655 if (user_mode(regs)) {
5656 regs_user->abi = perf_reg_abi(current);
5657 regs_user->regs = regs;
5658 } else if (!(current->flags & PF_KTHREAD)) {
5659 perf_get_regs_user(regs_user, regs, regs_user_copy);
5661 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5662 regs_user->regs = NULL;
5666 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5667 struct pt_regs *regs)
5669 regs_intr->regs = regs;
5670 regs_intr->abi = perf_reg_abi(current);
5675 * Get remaining task size from user stack pointer.
5677 * It'd be better to take stack vma map and limit this more
5678 * precisly, but there's no way to get it safely under interrupt,
5679 * so using TASK_SIZE as limit.
5681 static u64 perf_ustack_task_size(struct pt_regs *regs)
5683 unsigned long addr = perf_user_stack_pointer(regs);
5685 if (!addr || addr >= TASK_SIZE)
5688 return TASK_SIZE - addr;
5692 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5693 struct pt_regs *regs)
5697 /* No regs, no stack pointer, no dump. */
5702 * Check if we fit in with the requested stack size into the:
5704 * If we don't, we limit the size to the TASK_SIZE.
5706 * - remaining sample size
5707 * If we don't, we customize the stack size to
5708 * fit in to the remaining sample size.
5711 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5712 stack_size = min(stack_size, (u16) task_size);
5714 /* Current header size plus static size and dynamic size. */
5715 header_size += 2 * sizeof(u64);
5717 /* Do we fit in with the current stack dump size? */
5718 if ((u16) (header_size + stack_size) < header_size) {
5720 * If we overflow the maximum size for the sample,
5721 * we customize the stack dump size to fit in.
5723 stack_size = USHRT_MAX - header_size - sizeof(u64);
5724 stack_size = round_up(stack_size, sizeof(u64));
5731 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5732 struct pt_regs *regs)
5734 /* Case of a kernel thread, nothing to dump */
5737 perf_output_put(handle, size);
5747 * - the size requested by user or the best one we can fit
5748 * in to the sample max size
5750 * - user stack dump data
5752 * - the actual dumped size
5756 perf_output_put(handle, dump_size);
5759 sp = perf_user_stack_pointer(regs);
5762 rem = __output_copy_user(handle, (void *) sp, dump_size);
5764 dyn_size = dump_size - rem;
5766 perf_output_skip(handle, rem);
5769 perf_output_put(handle, dyn_size);
5773 static void __perf_event_header__init_id(struct perf_event_header *header,
5774 struct perf_sample_data *data,
5775 struct perf_event *event,
5778 data->type = event->attr.sample_type;
5779 header->size += event->id_header_size;
5781 if (sample_type & PERF_SAMPLE_TID) {
5782 /* namespace issues */
5783 data->tid_entry.pid = perf_event_pid(event, current);
5784 data->tid_entry.tid = perf_event_tid(event, current);
5787 if (sample_type & PERF_SAMPLE_TIME)
5788 data->time = perf_event_clock(event);
5790 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5791 data->id = primary_event_id(event);
5793 if (sample_type & PERF_SAMPLE_STREAM_ID)
5794 data->stream_id = event->id;
5796 if (sample_type & PERF_SAMPLE_CPU) {
5797 data->cpu_entry.cpu = raw_smp_processor_id();
5798 data->cpu_entry.reserved = 0;
5802 void perf_event_header__init_id(struct perf_event_header *header,
5803 struct perf_sample_data *data,
5804 struct perf_event *event)
5806 if (event->attr.sample_id_all)
5807 __perf_event_header__init_id(header, data, event, event->attr.sample_type);
5810 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5811 struct perf_sample_data *data)
5813 u64 sample_type = data->type;
5815 if (sample_type & PERF_SAMPLE_TID)
5816 perf_output_put(handle, data->tid_entry);
5818 if (sample_type & PERF_SAMPLE_TIME)
5819 perf_output_put(handle, data->time);
5821 if (sample_type & PERF_SAMPLE_ID)
5822 perf_output_put(handle, data->id);
5824 if (sample_type & PERF_SAMPLE_STREAM_ID)
5825 perf_output_put(handle, data->stream_id);
5827 if (sample_type & PERF_SAMPLE_CPU)
5828 perf_output_put(handle, data->cpu_entry);
5830 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5831 perf_output_put(handle, data->id);
5834 void perf_event__output_id_sample(struct perf_event *event,
5835 struct perf_output_handle *handle,
5836 struct perf_sample_data *sample)
5838 if (event->attr.sample_id_all)
5839 __perf_event__output_id_sample(handle, sample);
5842 static void perf_output_read_one(struct perf_output_handle *handle,
5843 struct perf_event *event,
5844 u64 enabled, u64 running)
5846 u64 read_format = event->attr.read_format;
5850 values[n++] = perf_event_count(event);
5851 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5852 values[n++] = enabled +
5853 atomic64_read(&event->child_total_time_enabled);
5855 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5856 values[n++] = running +
5857 atomic64_read(&event->child_total_time_running);
5859 if (read_format & PERF_FORMAT_ID)
5860 values[n++] = primary_event_id(event);
5862 __output_copy(handle, values, n * sizeof(u64));
5865 static void perf_output_read_group(struct perf_output_handle *handle,
5866 struct perf_event *event,
5867 u64 enabled, u64 running)
5869 struct perf_event *leader = event->group_leader, *sub;
5870 u64 read_format = event->attr.read_format;
5874 values[n++] = 1 + leader->nr_siblings;
5876 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5877 values[n++] = enabled;
5879 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5880 values[n++] = running;
5882 if ((leader != event) &&
5883 (leader->state == PERF_EVENT_STATE_ACTIVE))
5884 leader->pmu->read(leader);
5886 values[n++] = perf_event_count(leader);
5887 if (read_format & PERF_FORMAT_ID)
5888 values[n++] = primary_event_id(leader);
5890 __output_copy(handle, values, n * sizeof(u64));
5892 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5895 if ((sub != event) &&
5896 (sub->state == PERF_EVENT_STATE_ACTIVE))
5897 sub->pmu->read(sub);
5899 values[n++] = perf_event_count(sub);
5900 if (read_format & PERF_FORMAT_ID)
5901 values[n++] = primary_event_id(sub);
5903 __output_copy(handle, values, n * sizeof(u64));
5907 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5908 PERF_FORMAT_TOTAL_TIME_RUNNING)
5911 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5913 * The problem is that its both hard and excessively expensive to iterate the
5914 * child list, not to mention that its impossible to IPI the children running
5915 * on another CPU, from interrupt/NMI context.
5917 static void perf_output_read(struct perf_output_handle *handle,
5918 struct perf_event *event)
5920 u64 enabled = 0, running = 0, now;
5921 u64 read_format = event->attr.read_format;
5924 * compute total_time_enabled, total_time_running
5925 * based on snapshot values taken when the event
5926 * was last scheduled in.
5928 * we cannot simply called update_context_time()
5929 * because of locking issue as we are called in
5932 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5933 calc_timer_values(event, &now, &enabled, &running);
5935 if (event->attr.read_format & PERF_FORMAT_GROUP)
5936 perf_output_read_group(handle, event, enabled, running);
5938 perf_output_read_one(handle, event, enabled, running);
5941 void perf_output_sample(struct perf_output_handle *handle,
5942 struct perf_event_header *header,
5943 struct perf_sample_data *data,
5944 struct perf_event *event)
5946 u64 sample_type = data->type;
5948 perf_output_put(handle, *header);
5950 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5951 perf_output_put(handle, data->id);
5953 if (sample_type & PERF_SAMPLE_IP)
5954 perf_output_put(handle, data->ip);
5956 if (sample_type & PERF_SAMPLE_TID)
5957 perf_output_put(handle, data->tid_entry);
5959 if (sample_type & PERF_SAMPLE_TIME)
5960 perf_output_put(handle, data->time);
5962 if (sample_type & PERF_SAMPLE_ADDR)
5963 perf_output_put(handle, data->addr);
5965 if (sample_type & PERF_SAMPLE_ID)
5966 perf_output_put(handle, data->id);
5968 if (sample_type & PERF_SAMPLE_STREAM_ID)
5969 perf_output_put(handle, data->stream_id);
5971 if (sample_type & PERF_SAMPLE_CPU)
5972 perf_output_put(handle, data->cpu_entry);
5974 if (sample_type & PERF_SAMPLE_PERIOD)
5975 perf_output_put(handle, data->period);
5977 if (sample_type & PERF_SAMPLE_READ)
5978 perf_output_read(handle, event);
5980 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5981 if (data->callchain) {
5984 if (data->callchain)
5985 size += data->callchain->nr;
5987 size *= sizeof(u64);
5989 __output_copy(handle, data->callchain, size);
5992 perf_output_put(handle, nr);
5996 if (sample_type & PERF_SAMPLE_RAW) {
5997 struct perf_raw_record *raw = data->raw;
6000 struct perf_raw_frag *frag = &raw->frag;
6002 perf_output_put(handle, raw->size);
6005 __output_custom(handle, frag->copy,
6006 frag->data, frag->size);
6008 __output_copy(handle, frag->data,
6011 if (perf_raw_frag_last(frag))
6016 __output_skip(handle, NULL, frag->pad);
6022 .size = sizeof(u32),
6025 perf_output_put(handle, raw);
6029 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6030 if (data->br_stack) {
6033 size = data->br_stack->nr
6034 * sizeof(struct perf_branch_entry);
6036 perf_output_put(handle, data->br_stack->nr);
6037 perf_output_copy(handle, data->br_stack->entries, size);
6040 * we always store at least the value of nr
6043 perf_output_put(handle, nr);
6047 if (sample_type & PERF_SAMPLE_REGS_USER) {
6048 u64 abi = data->regs_user.abi;
6051 * If there are no regs to dump, notice it through
6052 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6054 perf_output_put(handle, abi);
6057 u64 mask = event->attr.sample_regs_user;
6058 perf_output_sample_regs(handle,
6059 data->regs_user.regs,
6064 if (sample_type & PERF_SAMPLE_STACK_USER) {
6065 perf_output_sample_ustack(handle,
6066 data->stack_user_size,
6067 data->regs_user.regs);
6070 if (sample_type & PERF_SAMPLE_WEIGHT)
6071 perf_output_put(handle, data->weight);
6073 if (sample_type & PERF_SAMPLE_DATA_SRC)
6074 perf_output_put(handle, data->data_src.val);
6076 if (sample_type & PERF_SAMPLE_TRANSACTION)
6077 perf_output_put(handle, data->txn);
6079 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6080 u64 abi = data->regs_intr.abi;
6082 * If there are no regs to dump, notice it through
6083 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6085 perf_output_put(handle, abi);
6088 u64 mask = event->attr.sample_regs_intr;
6090 perf_output_sample_regs(handle,
6091 data->regs_intr.regs,
6096 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6097 perf_output_put(handle, data->phys_addr);
6099 if (!event->attr.watermark) {
6100 int wakeup_events = event->attr.wakeup_events;
6102 if (wakeup_events) {
6103 struct ring_buffer *rb = handle->rb;
6104 int events = local_inc_return(&rb->events);
6106 if (events >= wakeup_events) {
6107 local_sub(wakeup_events, &rb->events);
6108 local_inc(&rb->wakeup);
6114 static u64 perf_virt_to_phys(u64 virt)
6121 if (virt >= TASK_SIZE) {
6122 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6123 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6124 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6125 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6128 * Walking the pages tables for user address.
6129 * Interrupts are disabled, so it prevents any tear down
6130 * of the page tables.
6131 * Try IRQ-safe __get_user_pages_fast first.
6132 * If failed, leave phys_addr as 0.
6134 if (current->mm != NULL) {
6137 pagefault_disable();
6138 if (__get_user_pages_fast(virt, 1, 0, &p) == 1) {
6139 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6149 void perf_prepare_sample(struct perf_event_header *header,
6150 struct perf_sample_data *data,
6151 struct perf_event *event,
6152 struct pt_regs *regs)
6154 u64 sample_type = event->attr.sample_type;
6155 u64 filtered_sample_type;
6157 header->type = PERF_RECORD_SAMPLE;
6158 header->size = sizeof(*header) + event->header_size;
6161 header->misc |= perf_misc_flags(regs);
6164 * Clear the sample flags that have already been done by the
6167 filtered_sample_type = sample_type & ~data->sample_flags;
6168 __perf_event_header__init_id(header, data, event, filtered_sample_type);
6170 if (sample_type & PERF_SAMPLE_IP)
6171 data->ip = perf_instruction_pointer(regs);
6173 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6176 data->callchain = perf_callchain(event, regs);
6178 if (data->callchain)
6179 size += data->callchain->nr;
6181 header->size += size * sizeof(u64);
6184 if (sample_type & PERF_SAMPLE_RAW) {
6185 struct perf_raw_record *raw = data->raw;
6189 struct perf_raw_frag *frag = &raw->frag;
6194 if (perf_raw_frag_last(frag))
6199 size = round_up(sum + sizeof(u32), sizeof(u64));
6200 raw->size = size - sizeof(u32);
6201 frag->pad = raw->size - sum;
6206 header->size += size;
6209 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6210 int size = sizeof(u64); /* nr */
6211 if (data->br_stack) {
6212 size += data->br_stack->nr
6213 * sizeof(struct perf_branch_entry);
6215 header->size += size;
6218 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6219 perf_sample_regs_user(&data->regs_user, regs,
6220 &data->regs_user_copy);
6222 if (sample_type & PERF_SAMPLE_REGS_USER) {
6223 /* regs dump ABI info */
6224 int size = sizeof(u64);
6226 if (data->regs_user.regs) {
6227 u64 mask = event->attr.sample_regs_user;
6228 size += hweight64(mask) * sizeof(u64);
6231 header->size += size;
6234 if (sample_type & PERF_SAMPLE_STACK_USER) {
6236 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6237 * processed as the last one or have additional check added
6238 * in case new sample type is added, because we could eat
6239 * up the rest of the sample size.
6241 u16 stack_size = event->attr.sample_stack_user;
6242 u16 size = sizeof(u64);
6244 stack_size = perf_sample_ustack_size(stack_size, header->size,
6245 data->regs_user.regs);
6248 * If there is something to dump, add space for the dump
6249 * itself and for the field that tells the dynamic size,
6250 * which is how many have been actually dumped.
6253 size += sizeof(u64) + stack_size;
6255 data->stack_user_size = stack_size;
6256 header->size += size;
6259 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6260 /* regs dump ABI info */
6261 int size = sizeof(u64);
6263 perf_sample_regs_intr(&data->regs_intr, regs);
6265 if (data->regs_intr.regs) {
6266 u64 mask = event->attr.sample_regs_intr;
6268 size += hweight64(mask) * sizeof(u64);
6271 header->size += size;
6274 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6275 data->phys_addr = perf_virt_to_phys(data->addr);
6278 static void __always_inline
6279 __perf_event_output(struct perf_event *event,
6280 struct perf_sample_data *data,
6281 struct pt_regs *regs,
6282 int (*output_begin)(struct perf_output_handle *,
6283 struct perf_event *,
6286 struct perf_output_handle handle;
6287 struct perf_event_header header;
6289 /* protect the callchain buffers */
6292 perf_prepare_sample(&header, data, event, regs);
6294 if (output_begin(&handle, event, header.size))
6297 perf_output_sample(&handle, &header, data, event);
6299 perf_output_end(&handle);
6306 perf_event_output_forward(struct perf_event *event,
6307 struct perf_sample_data *data,
6308 struct pt_regs *regs)
6310 __perf_event_output(event, data, regs, perf_output_begin_forward);
6314 perf_event_output_backward(struct perf_event *event,
6315 struct perf_sample_data *data,
6316 struct pt_regs *regs)
6318 __perf_event_output(event, data, regs, perf_output_begin_backward);
6322 perf_event_output(struct perf_event *event,
6323 struct perf_sample_data *data,
6324 struct pt_regs *regs)
6326 __perf_event_output(event, data, regs, perf_output_begin);
6333 struct perf_read_event {
6334 struct perf_event_header header;
6341 perf_event_read_event(struct perf_event *event,
6342 struct task_struct *task)
6344 struct perf_output_handle handle;
6345 struct perf_sample_data sample;
6346 struct perf_read_event read_event = {
6348 .type = PERF_RECORD_READ,
6350 .size = sizeof(read_event) + event->read_size,
6352 .pid = perf_event_pid(event, task),
6353 .tid = perf_event_tid(event, task),
6357 perf_event_header__init_id(&read_event.header, &sample, event);
6358 ret = perf_output_begin(&handle, event, read_event.header.size);
6362 perf_output_put(&handle, read_event);
6363 perf_output_read(&handle, event);
6364 perf_event__output_id_sample(event, &handle, &sample);
6366 perf_output_end(&handle);
6369 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6372 perf_iterate_ctx(struct perf_event_context *ctx,
6373 perf_iterate_f output,
6374 void *data, bool all)
6376 struct perf_event *event;
6378 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6380 if (event->state < PERF_EVENT_STATE_INACTIVE)
6382 if (!event_filter_match(event))
6386 output(event, data);
6390 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6392 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6393 struct perf_event *event;
6395 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6397 * Skip events that are not fully formed yet; ensure that
6398 * if we observe event->ctx, both event and ctx will be
6399 * complete enough. See perf_install_in_context().
6401 if (!smp_load_acquire(&event->ctx))
6404 if (event->state < PERF_EVENT_STATE_INACTIVE)
6406 if (!event_filter_match(event))
6408 output(event, data);
6413 * Iterate all events that need to receive side-band events.
6415 * For new callers; ensure that account_pmu_sb_event() includes
6416 * your event, otherwise it might not get delivered.
6419 perf_iterate_sb(perf_iterate_f output, void *data,
6420 struct perf_event_context *task_ctx)
6422 struct perf_event_context *ctx;
6429 * If we have task_ctx != NULL we only notify the task context itself.
6430 * The task_ctx is set only for EXIT events before releasing task
6434 perf_iterate_ctx(task_ctx, output, data, false);
6438 perf_iterate_sb_cpu(output, data);
6440 for_each_task_context_nr(ctxn) {
6441 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6443 perf_iterate_ctx(ctx, output, data, false);
6451 * Clear all file-based filters at exec, they'll have to be
6452 * re-instated when/if these objects are mmapped again.
6454 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6456 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6457 struct perf_addr_filter *filter;
6458 unsigned int restart = 0, count = 0;
6459 unsigned long flags;
6461 if (!has_addr_filter(event))
6464 raw_spin_lock_irqsave(&ifh->lock, flags);
6465 list_for_each_entry(filter, &ifh->list, entry) {
6466 if (filter->path.dentry) {
6467 event->addr_filters_offs[count] = 0;
6475 event->addr_filters_gen++;
6476 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6479 perf_event_stop(event, 1);
6482 void perf_event_exec(void)
6484 struct perf_event_context *ctx;
6488 for_each_task_context_nr(ctxn) {
6489 ctx = current->perf_event_ctxp[ctxn];
6493 perf_event_enable_on_exec(ctxn);
6495 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6501 struct remote_output {
6502 struct ring_buffer *rb;
6506 static void __perf_event_output_stop(struct perf_event *event, void *data)
6508 struct perf_event *parent = event->parent;
6509 struct remote_output *ro = data;
6510 struct ring_buffer *rb = ro->rb;
6511 struct stop_event_data sd = {
6515 if (!has_aux(event))
6522 * In case of inheritance, it will be the parent that links to the
6523 * ring-buffer, but it will be the child that's actually using it.
6525 * We are using event::rb to determine if the event should be stopped,
6526 * however this may race with ring_buffer_attach() (through set_output),
6527 * which will make us skip the event that actually needs to be stopped.
6528 * So ring_buffer_attach() has to stop an aux event before re-assigning
6531 if (rcu_dereference(parent->rb) == rb)
6532 ro->err = __perf_event_stop(&sd);
6535 static int __perf_pmu_output_stop(void *info)
6537 struct perf_event *event = info;
6538 struct pmu *pmu = event->pmu;
6539 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6540 struct remote_output ro = {
6545 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6546 if (cpuctx->task_ctx)
6547 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6554 static void perf_pmu_output_stop(struct perf_event *event)
6556 struct perf_event *iter;
6561 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6563 * For per-CPU events, we need to make sure that neither they
6564 * nor their children are running; for cpu==-1 events it's
6565 * sufficient to stop the event itself if it's active, since
6566 * it can't have children.
6570 cpu = READ_ONCE(iter->oncpu);
6575 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6576 if (err == -EAGAIN) {
6585 * task tracking -- fork/exit
6587 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6590 struct perf_task_event {
6591 struct task_struct *task;
6592 struct perf_event_context *task_ctx;
6595 struct perf_event_header header;
6605 static int perf_event_task_match(struct perf_event *event)
6607 return event->attr.comm || event->attr.mmap ||
6608 event->attr.mmap2 || event->attr.mmap_data ||
6612 static void perf_event_task_output(struct perf_event *event,
6615 struct perf_task_event *task_event = data;
6616 struct perf_output_handle handle;
6617 struct perf_sample_data sample;
6618 struct task_struct *task = task_event->task;
6619 int ret, size = task_event->event_id.header.size;
6621 if (!perf_event_task_match(event))
6624 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6626 ret = perf_output_begin(&handle, event,
6627 task_event->event_id.header.size);
6631 task_event->event_id.pid = perf_event_pid(event, task);
6632 task_event->event_id.tid = perf_event_tid(event, task);
6634 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
6635 task_event->event_id.ppid = perf_event_pid(event,
6637 task_event->event_id.ptid = perf_event_pid(event,
6639 } else { /* PERF_RECORD_FORK */
6640 task_event->event_id.ppid = perf_event_pid(event, current);
6641 task_event->event_id.ptid = perf_event_tid(event, current);
6644 task_event->event_id.time = perf_event_clock(event);
6646 perf_output_put(&handle, task_event->event_id);
6648 perf_event__output_id_sample(event, &handle, &sample);
6650 perf_output_end(&handle);
6652 task_event->event_id.header.size = size;
6655 static void perf_event_task(struct task_struct *task,
6656 struct perf_event_context *task_ctx,
6659 struct perf_task_event task_event;
6661 if (!atomic_read(&nr_comm_events) &&
6662 !atomic_read(&nr_mmap_events) &&
6663 !atomic_read(&nr_task_events))
6666 task_event = (struct perf_task_event){
6668 .task_ctx = task_ctx,
6671 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6673 .size = sizeof(task_event.event_id),
6683 perf_iterate_sb(perf_event_task_output,
6688 void perf_event_fork(struct task_struct *task)
6690 perf_event_task(task, NULL, 1);
6691 perf_event_namespaces(task);
6698 struct perf_comm_event {
6699 struct task_struct *task;
6704 struct perf_event_header header;
6711 static int perf_event_comm_match(struct perf_event *event)
6713 return event->attr.comm;
6716 static void perf_event_comm_output(struct perf_event *event,
6719 struct perf_comm_event *comm_event = data;
6720 struct perf_output_handle handle;
6721 struct perf_sample_data sample;
6722 int size = comm_event->event_id.header.size;
6725 if (!perf_event_comm_match(event))
6728 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6729 ret = perf_output_begin(&handle, event,
6730 comm_event->event_id.header.size);
6735 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6736 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6738 perf_output_put(&handle, comm_event->event_id);
6739 __output_copy(&handle, comm_event->comm,
6740 comm_event->comm_size);
6742 perf_event__output_id_sample(event, &handle, &sample);
6744 perf_output_end(&handle);
6746 comm_event->event_id.header.size = size;
6749 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6751 char comm[TASK_COMM_LEN];
6754 memset(comm, 0, sizeof(comm));
6755 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6756 size = ALIGN(strlen(comm)+1, sizeof(u64));
6758 comm_event->comm = comm;
6759 comm_event->comm_size = size;
6761 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6763 perf_iterate_sb(perf_event_comm_output,
6768 void perf_event_comm(struct task_struct *task, bool exec)
6770 struct perf_comm_event comm_event;
6772 if (!atomic_read(&nr_comm_events))
6775 comm_event = (struct perf_comm_event){
6781 .type = PERF_RECORD_COMM,
6782 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6790 perf_event_comm_event(&comm_event);
6794 * namespaces tracking
6797 struct perf_namespaces_event {
6798 struct task_struct *task;
6801 struct perf_event_header header;
6806 struct perf_ns_link_info link_info[NR_NAMESPACES];
6810 static int perf_event_namespaces_match(struct perf_event *event)
6812 return event->attr.namespaces;
6815 static void perf_event_namespaces_output(struct perf_event *event,
6818 struct perf_namespaces_event *namespaces_event = data;
6819 struct perf_output_handle handle;
6820 struct perf_sample_data sample;
6821 u16 header_size = namespaces_event->event_id.header.size;
6824 if (!perf_event_namespaces_match(event))
6827 perf_event_header__init_id(&namespaces_event->event_id.header,
6829 ret = perf_output_begin(&handle, event,
6830 namespaces_event->event_id.header.size);
6834 namespaces_event->event_id.pid = perf_event_pid(event,
6835 namespaces_event->task);
6836 namespaces_event->event_id.tid = perf_event_tid(event,
6837 namespaces_event->task);
6839 perf_output_put(&handle, namespaces_event->event_id);
6841 perf_event__output_id_sample(event, &handle, &sample);
6843 perf_output_end(&handle);
6845 namespaces_event->event_id.header.size = header_size;
6848 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6849 struct task_struct *task,
6850 const struct proc_ns_operations *ns_ops)
6852 struct path ns_path;
6853 struct inode *ns_inode;
6856 error = ns_get_path(&ns_path, task, ns_ops);
6858 ns_inode = ns_path.dentry->d_inode;
6859 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6860 ns_link_info->ino = ns_inode->i_ino;
6865 void perf_event_namespaces(struct task_struct *task)
6867 struct perf_namespaces_event namespaces_event;
6868 struct perf_ns_link_info *ns_link_info;
6870 if (!atomic_read(&nr_namespaces_events))
6873 namespaces_event = (struct perf_namespaces_event){
6877 .type = PERF_RECORD_NAMESPACES,
6879 .size = sizeof(namespaces_event.event_id),
6883 .nr_namespaces = NR_NAMESPACES,
6884 /* .link_info[NR_NAMESPACES] */
6888 ns_link_info = namespaces_event.event_id.link_info;
6890 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6891 task, &mntns_operations);
6893 #ifdef CONFIG_USER_NS
6894 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6895 task, &userns_operations);
6897 #ifdef CONFIG_NET_NS
6898 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6899 task, &netns_operations);
6901 #ifdef CONFIG_UTS_NS
6902 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6903 task, &utsns_operations);
6905 #ifdef CONFIG_IPC_NS
6906 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6907 task, &ipcns_operations);
6909 #ifdef CONFIG_PID_NS
6910 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6911 task, &pidns_operations);
6913 #ifdef CONFIG_CGROUPS
6914 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6915 task, &cgroupns_operations);
6918 perf_iterate_sb(perf_event_namespaces_output,
6927 struct perf_mmap_event {
6928 struct vm_area_struct *vma;
6930 const char *file_name;
6938 struct perf_event_header header;
6948 static int perf_event_mmap_match(struct perf_event *event,
6951 struct perf_mmap_event *mmap_event = data;
6952 struct vm_area_struct *vma = mmap_event->vma;
6953 int executable = vma->vm_flags & VM_EXEC;
6955 return (!executable && event->attr.mmap_data) ||
6956 (executable && (event->attr.mmap || event->attr.mmap2));
6959 static void perf_event_mmap_output(struct perf_event *event,
6962 struct perf_mmap_event *mmap_event = data;
6963 struct perf_output_handle handle;
6964 struct perf_sample_data sample;
6965 int size = mmap_event->event_id.header.size;
6966 u32 type = mmap_event->event_id.header.type;
6969 if (!perf_event_mmap_match(event, data))
6972 if (event->attr.mmap2) {
6973 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6974 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6975 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6976 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6977 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6978 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6979 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6982 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6983 ret = perf_output_begin(&handle, event,
6984 mmap_event->event_id.header.size);
6988 mmap_event->event_id.pid = perf_event_pid(event, current);
6989 mmap_event->event_id.tid = perf_event_tid(event, current);
6991 perf_output_put(&handle, mmap_event->event_id);
6993 if (event->attr.mmap2) {
6994 perf_output_put(&handle, mmap_event->maj);
6995 perf_output_put(&handle, mmap_event->min);
6996 perf_output_put(&handle, mmap_event->ino);
6997 perf_output_put(&handle, mmap_event->ino_generation);
6998 perf_output_put(&handle, mmap_event->prot);
6999 perf_output_put(&handle, mmap_event->flags);
7002 __output_copy(&handle, mmap_event->file_name,
7003 mmap_event->file_size);
7005 perf_event__output_id_sample(event, &handle, &sample);
7007 perf_output_end(&handle);
7009 mmap_event->event_id.header.size = size;
7010 mmap_event->event_id.header.type = type;
7013 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7015 struct vm_area_struct *vma = mmap_event->vma;
7016 struct file *file = vma->vm_file;
7017 int maj = 0, min = 0;
7018 u64 ino = 0, gen = 0;
7019 u32 prot = 0, flags = 0;
7025 if (vma->vm_flags & VM_READ)
7027 if (vma->vm_flags & VM_WRITE)
7029 if (vma->vm_flags & VM_EXEC)
7032 if (vma->vm_flags & VM_MAYSHARE)
7035 flags = MAP_PRIVATE;
7037 if (vma->vm_flags & VM_DENYWRITE)
7038 flags |= MAP_DENYWRITE;
7039 if (vma->vm_flags & VM_MAYEXEC)
7040 flags |= MAP_EXECUTABLE;
7041 if (vma->vm_flags & VM_LOCKED)
7042 flags |= MAP_LOCKED;
7043 if (vma->vm_flags & VM_HUGETLB)
7044 flags |= MAP_HUGETLB;
7047 struct inode *inode;
7050 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7056 * d_path() works from the end of the rb backwards, so we
7057 * need to add enough zero bytes after the string to handle
7058 * the 64bit alignment we do later.
7060 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7065 inode = file_inode(vma->vm_file);
7066 dev = inode->i_sb->s_dev;
7068 gen = inode->i_generation;
7074 if (vma->vm_ops && vma->vm_ops->name) {
7075 name = (char *) vma->vm_ops->name(vma);
7080 name = (char *)arch_vma_name(vma);
7084 if (vma->vm_start <= vma->vm_mm->start_brk &&
7085 vma->vm_end >= vma->vm_mm->brk) {
7089 if (vma->vm_start <= vma->vm_mm->start_stack &&
7090 vma->vm_end >= vma->vm_mm->start_stack) {
7100 strlcpy(tmp, name, sizeof(tmp));
7104 * Since our buffer works in 8 byte units we need to align our string
7105 * size to a multiple of 8. However, we must guarantee the tail end is
7106 * zero'd out to avoid leaking random bits to userspace.
7108 size = strlen(name)+1;
7109 while (!IS_ALIGNED(size, sizeof(u64)))
7110 name[size++] = '\0';
7112 mmap_event->file_name = name;
7113 mmap_event->file_size = size;
7114 mmap_event->maj = maj;
7115 mmap_event->min = min;
7116 mmap_event->ino = ino;
7117 mmap_event->ino_generation = gen;
7118 mmap_event->prot = prot;
7119 mmap_event->flags = flags;
7121 if (!(vma->vm_flags & VM_EXEC))
7122 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7124 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7126 perf_iterate_sb(perf_event_mmap_output,
7134 * Check whether inode and address range match filter criteria.
7136 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7137 struct file *file, unsigned long offset,
7140 /* d_inode(NULL) won't be equal to any mapped user-space file */
7141 if (!filter->path.dentry)
7144 if (d_inode(filter->path.dentry) != file_inode(file))
7147 if (filter->offset > offset + size)
7150 if (filter->offset + filter->size < offset)
7156 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7158 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7159 struct vm_area_struct *vma = data;
7160 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7161 struct file *file = vma->vm_file;
7162 struct perf_addr_filter *filter;
7163 unsigned int restart = 0, count = 0;
7165 if (!has_addr_filter(event))
7171 raw_spin_lock_irqsave(&ifh->lock, flags);
7172 list_for_each_entry(filter, &ifh->list, entry) {
7173 if (perf_addr_filter_match(filter, file, off,
7174 vma->vm_end - vma->vm_start)) {
7175 event->addr_filters_offs[count] = vma->vm_start;
7183 event->addr_filters_gen++;
7184 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7187 perf_event_stop(event, 1);
7191 * Adjust all task's events' filters to the new vma
7193 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7195 struct perf_event_context *ctx;
7199 * Data tracing isn't supported yet and as such there is no need
7200 * to keep track of anything that isn't related to executable code:
7202 if (!(vma->vm_flags & VM_EXEC))
7206 for_each_task_context_nr(ctxn) {
7207 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7211 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7216 void perf_event_mmap(struct vm_area_struct *vma)
7218 struct perf_mmap_event mmap_event;
7220 if (!atomic_read(&nr_mmap_events))
7223 mmap_event = (struct perf_mmap_event){
7229 .type = PERF_RECORD_MMAP,
7230 .misc = PERF_RECORD_MISC_USER,
7235 .start = vma->vm_start,
7236 .len = vma->vm_end - vma->vm_start,
7237 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7239 /* .maj (attr_mmap2 only) */
7240 /* .min (attr_mmap2 only) */
7241 /* .ino (attr_mmap2 only) */
7242 /* .ino_generation (attr_mmap2 only) */
7243 /* .prot (attr_mmap2 only) */
7244 /* .flags (attr_mmap2 only) */
7247 perf_addr_filters_adjust(vma);
7248 perf_event_mmap_event(&mmap_event);
7251 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7252 unsigned long size, u64 flags)
7254 struct perf_output_handle handle;
7255 struct perf_sample_data sample;
7256 struct perf_aux_event {
7257 struct perf_event_header header;
7263 .type = PERF_RECORD_AUX,
7265 .size = sizeof(rec),
7273 perf_event_header__init_id(&rec.header, &sample, event);
7274 ret = perf_output_begin(&handle, event, rec.header.size);
7279 perf_output_put(&handle, rec);
7280 perf_event__output_id_sample(event, &handle, &sample);
7282 perf_output_end(&handle);
7286 * Lost/dropped samples logging
7288 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7290 struct perf_output_handle handle;
7291 struct perf_sample_data sample;
7295 struct perf_event_header header;
7297 } lost_samples_event = {
7299 .type = PERF_RECORD_LOST_SAMPLES,
7301 .size = sizeof(lost_samples_event),
7306 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7308 ret = perf_output_begin(&handle, event,
7309 lost_samples_event.header.size);
7313 perf_output_put(&handle, lost_samples_event);
7314 perf_event__output_id_sample(event, &handle, &sample);
7315 perf_output_end(&handle);
7319 * context_switch tracking
7322 struct perf_switch_event {
7323 struct task_struct *task;
7324 struct task_struct *next_prev;
7327 struct perf_event_header header;
7333 static int perf_event_switch_match(struct perf_event *event)
7335 return event->attr.context_switch;
7338 static void perf_event_switch_output(struct perf_event *event, void *data)
7340 struct perf_switch_event *se = data;
7341 struct perf_output_handle handle;
7342 struct perf_sample_data sample;
7345 if (!perf_event_switch_match(event))
7348 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7349 if (event->ctx->task) {
7350 se->event_id.header.type = PERF_RECORD_SWITCH;
7351 se->event_id.header.size = sizeof(se->event_id.header);
7353 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7354 se->event_id.header.size = sizeof(se->event_id);
7355 se->event_id.next_prev_pid =
7356 perf_event_pid(event, se->next_prev);
7357 se->event_id.next_prev_tid =
7358 perf_event_tid(event, se->next_prev);
7361 perf_event_header__init_id(&se->event_id.header, &sample, event);
7363 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7367 if (event->ctx->task)
7368 perf_output_put(&handle, se->event_id.header);
7370 perf_output_put(&handle, se->event_id);
7372 perf_event__output_id_sample(event, &handle, &sample);
7374 perf_output_end(&handle);
7377 static void perf_event_switch(struct task_struct *task,
7378 struct task_struct *next_prev, bool sched_in)
7380 struct perf_switch_event switch_event;
7382 /* N.B. caller checks nr_switch_events != 0 */
7384 switch_event = (struct perf_switch_event){
7386 .next_prev = next_prev,
7390 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7393 /* .next_prev_pid */
7394 /* .next_prev_tid */
7398 perf_iterate_sb(perf_event_switch_output,
7404 * IRQ throttle logging
7407 static void perf_log_throttle(struct perf_event *event, int enable)
7409 struct perf_output_handle handle;
7410 struct perf_sample_data sample;
7414 struct perf_event_header header;
7418 } throttle_event = {
7420 .type = PERF_RECORD_THROTTLE,
7422 .size = sizeof(throttle_event),
7424 .time = perf_event_clock(event),
7425 .id = primary_event_id(event),
7426 .stream_id = event->id,
7430 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7432 perf_event_header__init_id(&throttle_event.header, &sample, event);
7434 ret = perf_output_begin(&handle, event,
7435 throttle_event.header.size);
7439 perf_output_put(&handle, throttle_event);
7440 perf_event__output_id_sample(event, &handle, &sample);
7441 perf_output_end(&handle);
7444 void perf_event_itrace_started(struct perf_event *event)
7446 event->attach_state |= PERF_ATTACH_ITRACE;
7449 static void perf_log_itrace_start(struct perf_event *event)
7451 struct perf_output_handle handle;
7452 struct perf_sample_data sample;
7453 struct perf_aux_event {
7454 struct perf_event_header header;
7461 event = event->parent;
7463 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7464 event->attach_state & PERF_ATTACH_ITRACE)
7467 rec.header.type = PERF_RECORD_ITRACE_START;
7468 rec.header.misc = 0;
7469 rec.header.size = sizeof(rec);
7470 rec.pid = perf_event_pid(event, current);
7471 rec.tid = perf_event_tid(event, current);
7473 perf_event_header__init_id(&rec.header, &sample, event);
7474 ret = perf_output_begin(&handle, event, rec.header.size);
7479 perf_output_put(&handle, rec);
7480 perf_event__output_id_sample(event, &handle, &sample);
7482 perf_output_end(&handle);
7486 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7488 struct hw_perf_event *hwc = &event->hw;
7492 seq = __this_cpu_read(perf_throttled_seq);
7493 if (seq != hwc->interrupts_seq) {
7494 hwc->interrupts_seq = seq;
7495 hwc->interrupts = 1;
7498 if (unlikely(throttle &&
7499 hwc->interrupts > max_samples_per_tick)) {
7500 __this_cpu_inc(perf_throttled_count);
7501 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7502 hwc->interrupts = MAX_INTERRUPTS;
7503 perf_log_throttle(event, 0);
7508 if (event->attr.freq) {
7509 u64 now = perf_clock();
7510 s64 delta = now - hwc->freq_time_stamp;
7512 hwc->freq_time_stamp = now;
7514 if (delta > 0 && delta < 2*TICK_NSEC)
7515 perf_adjust_period(event, delta, hwc->last_period, true);
7521 int perf_event_account_interrupt(struct perf_event *event)
7523 return __perf_event_account_interrupt(event, 1);
7527 * Generic event overflow handling, sampling.
7530 static int __perf_event_overflow(struct perf_event *event,
7531 int throttle, struct perf_sample_data *data,
7532 struct pt_regs *regs)
7534 int events = atomic_read(&event->event_limit);
7538 * Non-sampling counters might still use the PMI to fold short
7539 * hardware counters, ignore those.
7541 if (unlikely(!is_sampling_event(event)))
7544 ret = __perf_event_account_interrupt(event, throttle);
7547 * XXX event_limit might not quite work as expected on inherited
7551 event->pending_kill = POLL_IN;
7552 if (events && atomic_dec_and_test(&event->event_limit)) {
7554 event->pending_kill = POLL_HUP;
7556 perf_event_disable_inatomic(event);
7559 READ_ONCE(event->overflow_handler)(event, data, regs);
7561 if (*perf_event_fasync(event) && event->pending_kill) {
7562 event->pending_wakeup = 1;
7563 irq_work_queue(&event->pending);
7569 int perf_event_overflow(struct perf_event *event,
7570 struct perf_sample_data *data,
7571 struct pt_regs *regs)
7573 return __perf_event_overflow(event, 1, data, regs);
7577 * Generic software event infrastructure
7580 struct swevent_htable {
7581 struct swevent_hlist *swevent_hlist;
7582 struct mutex hlist_mutex;
7585 /* Recursion avoidance in each contexts */
7586 int recursion[PERF_NR_CONTEXTS];
7589 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7592 * We directly increment event->count and keep a second value in
7593 * event->hw.period_left to count intervals. This period event
7594 * is kept in the range [-sample_period, 0] so that we can use the
7598 u64 perf_swevent_set_period(struct perf_event *event)
7600 struct hw_perf_event *hwc = &event->hw;
7601 u64 period = hwc->last_period;
7605 hwc->last_period = hwc->sample_period;
7608 old = val = local64_read(&hwc->period_left);
7612 nr = div64_u64(period + val, period);
7613 offset = nr * period;
7615 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7621 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7622 struct perf_sample_data *data,
7623 struct pt_regs *regs)
7625 struct hw_perf_event *hwc = &event->hw;
7629 overflow = perf_swevent_set_period(event);
7631 if (hwc->interrupts == MAX_INTERRUPTS)
7634 for (; overflow; overflow--) {
7635 if (__perf_event_overflow(event, throttle,
7638 * We inhibit the overflow from happening when
7639 * hwc->interrupts == MAX_INTERRUPTS.
7647 static void perf_swevent_event(struct perf_event *event, u64 nr,
7648 struct perf_sample_data *data,
7649 struct pt_regs *regs)
7651 struct hw_perf_event *hwc = &event->hw;
7653 local64_add(nr, &event->count);
7658 if (!is_sampling_event(event))
7661 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7663 return perf_swevent_overflow(event, 1, data, regs);
7665 data->period = event->hw.last_period;
7667 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7668 return perf_swevent_overflow(event, 1, data, regs);
7670 if (local64_add_negative(nr, &hwc->period_left))
7673 perf_swevent_overflow(event, 0, data, regs);
7676 static int perf_exclude_event(struct perf_event *event,
7677 struct pt_regs *regs)
7679 if (event->hw.state & PERF_HES_STOPPED)
7683 if (event->attr.exclude_user && user_mode(regs))
7686 if (event->attr.exclude_kernel && !user_mode(regs))
7693 static int perf_swevent_match(struct perf_event *event,
7694 enum perf_type_id type,
7696 struct perf_sample_data *data,
7697 struct pt_regs *regs)
7699 if (event->attr.type != type)
7702 if (event->attr.config != event_id)
7705 if (perf_exclude_event(event, regs))
7711 static inline u64 swevent_hash(u64 type, u32 event_id)
7713 u64 val = event_id | (type << 32);
7715 return hash_64(val, SWEVENT_HLIST_BITS);
7718 static inline struct hlist_head *
7719 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7721 u64 hash = swevent_hash(type, event_id);
7723 return &hlist->heads[hash];
7726 /* For the read side: events when they trigger */
7727 static inline struct hlist_head *
7728 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7730 struct swevent_hlist *hlist;
7732 hlist = rcu_dereference(swhash->swevent_hlist);
7736 return __find_swevent_head(hlist, type, event_id);
7739 /* For the event head insertion and removal in the hlist */
7740 static inline struct hlist_head *
7741 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7743 struct swevent_hlist *hlist;
7744 u32 event_id = event->attr.config;
7745 u64 type = event->attr.type;
7748 * Event scheduling is always serialized against hlist allocation
7749 * and release. Which makes the protected version suitable here.
7750 * The context lock guarantees that.
7752 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7753 lockdep_is_held(&event->ctx->lock));
7757 return __find_swevent_head(hlist, type, event_id);
7760 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7762 struct perf_sample_data *data,
7763 struct pt_regs *regs)
7765 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7766 struct perf_event *event;
7767 struct hlist_head *head;
7770 head = find_swevent_head_rcu(swhash, type, event_id);
7774 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7775 if (perf_swevent_match(event, type, event_id, data, regs))
7776 perf_swevent_event(event, nr, data, regs);
7782 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7784 int perf_swevent_get_recursion_context(void)
7786 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7788 return get_recursion_context(swhash->recursion);
7790 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7792 void perf_swevent_put_recursion_context(int rctx)
7794 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7796 put_recursion_context(swhash->recursion, rctx);
7799 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7801 struct perf_sample_data data;
7803 if (WARN_ON_ONCE(!regs))
7806 perf_sample_data_init(&data, addr, 0);
7807 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7810 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7814 preempt_disable_notrace();
7815 rctx = perf_swevent_get_recursion_context();
7816 if (unlikely(rctx < 0))
7819 ___perf_sw_event(event_id, nr, regs, addr);
7821 perf_swevent_put_recursion_context(rctx);
7823 preempt_enable_notrace();
7826 static void perf_swevent_read(struct perf_event *event)
7830 static int perf_swevent_add(struct perf_event *event, int flags)
7832 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7833 struct hw_perf_event *hwc = &event->hw;
7834 struct hlist_head *head;
7836 if (is_sampling_event(event)) {
7837 hwc->last_period = hwc->sample_period;
7838 perf_swevent_set_period(event);
7841 hwc->state = !(flags & PERF_EF_START);
7843 head = find_swevent_head(swhash, event);
7844 if (WARN_ON_ONCE(!head))
7847 hlist_add_head_rcu(&event->hlist_entry, head);
7848 perf_event_update_userpage(event);
7853 static void perf_swevent_del(struct perf_event *event, int flags)
7855 hlist_del_rcu(&event->hlist_entry);
7858 static void perf_swevent_start(struct perf_event *event, int flags)
7860 event->hw.state = 0;
7863 static void perf_swevent_stop(struct perf_event *event, int flags)
7865 event->hw.state = PERF_HES_STOPPED;
7868 /* Deref the hlist from the update side */
7869 static inline struct swevent_hlist *
7870 swevent_hlist_deref(struct swevent_htable *swhash)
7872 return rcu_dereference_protected(swhash->swevent_hlist,
7873 lockdep_is_held(&swhash->hlist_mutex));
7876 static void swevent_hlist_release(struct swevent_htable *swhash)
7878 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7883 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7884 kfree_rcu(hlist, rcu_head);
7887 static void swevent_hlist_put_cpu(int cpu)
7889 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7891 mutex_lock(&swhash->hlist_mutex);
7893 if (!--swhash->hlist_refcount)
7894 swevent_hlist_release(swhash);
7896 mutex_unlock(&swhash->hlist_mutex);
7899 static void swevent_hlist_put(void)
7903 for_each_possible_cpu(cpu)
7904 swevent_hlist_put_cpu(cpu);
7907 static int swevent_hlist_get_cpu(int cpu)
7909 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7912 mutex_lock(&swhash->hlist_mutex);
7913 if (!swevent_hlist_deref(swhash) &&
7914 cpumask_test_cpu(cpu, perf_online_mask)) {
7915 struct swevent_hlist *hlist;
7917 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7922 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7924 swhash->hlist_refcount++;
7926 mutex_unlock(&swhash->hlist_mutex);
7931 static int swevent_hlist_get(void)
7933 int err, cpu, failed_cpu;
7935 mutex_lock(&pmus_lock);
7936 for_each_possible_cpu(cpu) {
7937 err = swevent_hlist_get_cpu(cpu);
7943 mutex_unlock(&pmus_lock);
7946 for_each_possible_cpu(cpu) {
7947 if (cpu == failed_cpu)
7949 swevent_hlist_put_cpu(cpu);
7951 mutex_unlock(&pmus_lock);
7955 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7957 static void sw_perf_event_destroy(struct perf_event *event)
7959 u64 event_id = event->attr.config;
7961 WARN_ON(event->parent);
7963 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7964 swevent_hlist_put();
7967 static int perf_swevent_init(struct perf_event *event)
7969 u64 event_id = event->attr.config;
7971 if (event->attr.type != PERF_TYPE_SOFTWARE)
7975 * no branch sampling for software events
7977 if (has_branch_stack(event))
7981 case PERF_COUNT_SW_CPU_CLOCK:
7982 case PERF_COUNT_SW_TASK_CLOCK:
7989 if (event_id >= PERF_COUNT_SW_MAX)
7992 if (!event->parent) {
7995 err = swevent_hlist_get();
7999 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8000 event->destroy = sw_perf_event_destroy;
8006 static struct pmu perf_swevent = {
8007 .task_ctx_nr = perf_sw_context,
8009 .capabilities = PERF_PMU_CAP_NO_NMI,
8011 .event_init = perf_swevent_init,
8012 .add = perf_swevent_add,
8013 .del = perf_swevent_del,
8014 .start = perf_swevent_start,
8015 .stop = perf_swevent_stop,
8016 .read = perf_swevent_read,
8019 #ifdef CONFIG_EVENT_TRACING
8021 static int perf_tp_filter_match(struct perf_event *event,
8022 struct perf_sample_data *data)
8024 void *record = data->raw->frag.data;
8026 /* only top level events have filters set */
8028 event = event->parent;
8030 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8035 static int perf_tp_event_match(struct perf_event *event,
8036 struct perf_sample_data *data,
8037 struct pt_regs *regs)
8039 if (event->hw.state & PERF_HES_STOPPED)
8042 * All tracepoints are from kernel-space.
8044 if (event->attr.exclude_kernel)
8047 if (!perf_tp_filter_match(event, data))
8053 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8054 struct trace_event_call *call, u64 count,
8055 struct pt_regs *regs, struct hlist_head *head,
8056 struct task_struct *task)
8058 struct bpf_prog *prog = call->prog;
8061 *(struct pt_regs **)raw_data = regs;
8062 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
8063 perf_swevent_put_recursion_context(rctx);
8067 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8070 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8072 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8073 struct pt_regs *regs, struct hlist_head *head, int rctx,
8074 struct task_struct *task, struct perf_event *event)
8076 struct perf_sample_data data;
8078 struct perf_raw_record raw = {
8085 perf_sample_data_init(&data, 0, 0);
8088 perf_trace_buf_update(record, event_type);
8090 /* Use the given event instead of the hlist */
8092 if (perf_tp_event_match(event, &data, regs))
8093 perf_swevent_event(event, count, &data, regs);
8095 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8096 if (perf_tp_event_match(event, &data, regs))
8097 perf_swevent_event(event, count, &data, regs);
8102 * If we got specified a target task, also iterate its context and
8103 * deliver this event there too.
8105 if (task && task != current) {
8106 struct perf_event_context *ctx;
8107 struct trace_entry *entry = record;
8110 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8114 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8115 if (event->cpu != smp_processor_id())
8117 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8119 if (event->attr.config != entry->type)
8121 if (perf_tp_event_match(event, &data, regs))
8122 perf_swevent_event(event, count, &data, regs);
8128 perf_swevent_put_recursion_context(rctx);
8130 EXPORT_SYMBOL_GPL(perf_tp_event);
8132 static void tp_perf_event_destroy(struct perf_event *event)
8134 perf_trace_destroy(event);
8137 static int perf_tp_event_init(struct perf_event *event)
8141 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8145 * no branch sampling for tracepoint events
8147 if (has_branch_stack(event))
8150 err = perf_trace_init(event);
8154 event->destroy = tp_perf_event_destroy;
8159 static struct pmu perf_tracepoint = {
8160 .task_ctx_nr = perf_sw_context,
8162 .event_init = perf_tp_event_init,
8163 .add = perf_trace_add,
8164 .del = perf_trace_del,
8165 .start = perf_swevent_start,
8166 .stop = perf_swevent_stop,
8167 .read = perf_swevent_read,
8170 static inline void perf_tp_register(void)
8172 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8175 static void perf_event_free_filter(struct perf_event *event)
8177 ftrace_profile_free_filter(event);
8180 #ifdef CONFIG_BPF_SYSCALL
8181 static void bpf_overflow_handler(struct perf_event *event,
8182 struct perf_sample_data *data,
8183 struct pt_regs *regs)
8185 struct bpf_perf_event_data_kern ctx = {
8192 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8195 ret = BPF_PROG_RUN(event->prog, &ctx);
8198 __this_cpu_dec(bpf_prog_active);
8203 event->orig_overflow_handler(event, data, regs);
8206 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8208 struct bpf_prog *prog;
8210 if (event->overflow_handler_context)
8211 /* hw breakpoint or kernel counter */
8217 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8219 return PTR_ERR(prog);
8222 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8223 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8227 static void perf_event_free_bpf_handler(struct perf_event *event)
8229 struct bpf_prog *prog = event->prog;
8234 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8239 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8243 static void perf_event_free_bpf_handler(struct perf_event *event)
8248 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8250 bool is_kprobe, is_tracepoint, is_syscall_tp;
8251 struct bpf_prog *prog;
8253 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8254 return perf_event_set_bpf_handler(event, prog_fd);
8256 if (event->tp_event->prog)
8259 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8260 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8261 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8262 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8263 /* bpf programs can only be attached to u/kprobe or tracepoint */
8266 prog = bpf_prog_get(prog_fd);
8268 return PTR_ERR(prog);
8270 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8271 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8272 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8273 /* valid fd, but invalid bpf program type */
8278 if (is_tracepoint || is_syscall_tp) {
8279 int off = trace_event_get_offsets(event->tp_event);
8281 if (prog->aux->max_ctx_offset > off) {
8286 event->tp_event->prog = prog;
8287 event->tp_event->bpf_prog_owner = event;
8292 static void perf_event_free_bpf_prog(struct perf_event *event)
8294 struct bpf_prog *prog;
8296 perf_event_free_bpf_handler(event);
8298 if (!event->tp_event)
8301 prog = event->tp_event->prog;
8302 if (prog && event->tp_event->bpf_prog_owner == event) {
8303 event->tp_event->prog = NULL;
8310 static inline void perf_tp_register(void)
8314 static void perf_event_free_filter(struct perf_event *event)
8318 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8323 static void perf_event_free_bpf_prog(struct perf_event *event)
8326 #endif /* CONFIG_EVENT_TRACING */
8328 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8329 void perf_bp_event(struct perf_event *bp, void *data)
8331 struct perf_sample_data sample;
8332 struct pt_regs *regs = data;
8334 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8336 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8337 perf_swevent_event(bp, 1, &sample, regs);
8342 * Allocate a new address filter
8344 static struct perf_addr_filter *
8345 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8347 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8348 struct perf_addr_filter *filter;
8350 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8354 INIT_LIST_HEAD(&filter->entry);
8355 list_add_tail(&filter->entry, filters);
8360 static void free_filters_list(struct list_head *filters)
8362 struct perf_addr_filter *filter, *iter;
8364 list_for_each_entry_safe(filter, iter, filters, entry) {
8365 path_put(&filter->path);
8366 list_del(&filter->entry);
8372 * Free existing address filters and optionally install new ones
8374 static void perf_addr_filters_splice(struct perf_event *event,
8375 struct list_head *head)
8377 unsigned long flags;
8380 if (!has_addr_filter(event))
8383 /* don't bother with children, they don't have their own filters */
8387 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8389 list_splice_init(&event->addr_filters.list, &list);
8391 list_splice(head, &event->addr_filters.list);
8393 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8395 free_filters_list(&list);
8399 * Scan through mm's vmas and see if one of them matches the
8400 * @filter; if so, adjust filter's address range.
8401 * Called with mm::mmap_sem down for reading.
8403 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8404 struct mm_struct *mm)
8406 struct vm_area_struct *vma;
8408 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8409 struct file *file = vma->vm_file;
8410 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8411 unsigned long vma_size = vma->vm_end - vma->vm_start;
8416 if (!perf_addr_filter_match(filter, file, off, vma_size))
8419 return vma->vm_start;
8426 * Update event's address range filters based on the
8427 * task's existing mappings, if any.
8429 static void perf_event_addr_filters_apply(struct perf_event *event)
8431 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8432 struct task_struct *task = READ_ONCE(event->ctx->task);
8433 struct perf_addr_filter *filter;
8434 struct mm_struct *mm = NULL;
8435 unsigned int count = 0;
8436 unsigned long flags;
8439 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8440 * will stop on the parent's child_mutex that our caller is also holding
8442 if (task == TASK_TOMBSTONE)
8445 if (!ifh->nr_file_filters)
8448 mm = get_task_mm(task);
8452 down_read(&mm->mmap_sem);
8454 raw_spin_lock_irqsave(&ifh->lock, flags);
8455 list_for_each_entry(filter, &ifh->list, entry) {
8456 event->addr_filters_offs[count] = 0;
8459 * Adjust base offset if the filter is associated to a binary
8460 * that needs to be mapped:
8462 if (filter->path.dentry)
8463 event->addr_filters_offs[count] =
8464 perf_addr_filter_apply(filter, mm);
8469 event->addr_filters_gen++;
8470 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8472 up_read(&mm->mmap_sem);
8477 perf_event_stop(event, 1);
8481 * Address range filtering: limiting the data to certain
8482 * instruction address ranges. Filters are ioctl()ed to us from
8483 * userspace as ascii strings.
8485 * Filter string format:
8488 * where ACTION is one of the
8489 * * "filter": limit the trace to this region
8490 * * "start": start tracing from this address
8491 * * "stop": stop tracing at this address/region;
8493 * * for kernel addresses: <start address>[/<size>]
8494 * * for object files: <start address>[/<size>]@</path/to/object/file>
8496 * if <size> is not specified, the range is treated as a single address.
8510 IF_STATE_ACTION = 0,
8515 static const match_table_t if_tokens = {
8516 { IF_ACT_FILTER, "filter" },
8517 { IF_ACT_START, "start" },
8518 { IF_ACT_STOP, "stop" },
8519 { IF_SRC_FILE, "%u/%u@%s" },
8520 { IF_SRC_KERNEL, "%u/%u" },
8521 { IF_SRC_FILEADDR, "%u@%s" },
8522 { IF_SRC_KERNELADDR, "%u" },
8523 { IF_ACT_NONE, NULL },
8527 * Address filter string parser
8530 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8531 struct list_head *filters)
8533 struct perf_addr_filter *filter = NULL;
8534 char *start, *orig, *filename = NULL;
8535 substring_t args[MAX_OPT_ARGS];
8536 int state = IF_STATE_ACTION, token;
8537 unsigned int kernel = 0;
8540 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8544 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8550 /* filter definition begins */
8551 if (state == IF_STATE_ACTION) {
8552 filter = perf_addr_filter_new(event, filters);
8557 token = match_token(start, if_tokens, args);
8564 if (state != IF_STATE_ACTION)
8567 state = IF_STATE_SOURCE;
8570 case IF_SRC_KERNELADDR:
8574 case IF_SRC_FILEADDR:
8576 if (state != IF_STATE_SOURCE)
8579 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8583 ret = kstrtoul(args[0].from, 0, &filter->offset);
8587 if (filter->range) {
8589 ret = kstrtoul(args[1].from, 0, &filter->size);
8594 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8595 int fpos = filter->range ? 2 : 1;
8598 filename = match_strdup(&args[fpos]);
8605 state = IF_STATE_END;
8613 * Filter definition is fully parsed, validate and install it.
8614 * Make sure that it doesn't contradict itself or the event's
8617 if (state == IF_STATE_END) {
8619 if (kernel && event->attr.exclude_kernel)
8627 * For now, we only support file-based filters
8628 * in per-task events; doing so for CPU-wide
8629 * events requires additional context switching
8630 * trickery, since same object code will be
8631 * mapped at different virtual addresses in
8632 * different processes.
8635 if (!event->ctx->task)
8638 /* look up the path and grab its inode */
8639 ret = kern_path(filename, LOOKUP_FOLLOW,
8645 if (!filter->path.dentry ||
8646 !S_ISREG(d_inode(filter->path.dentry)
8650 event->addr_filters.nr_file_filters++;
8653 /* ready to consume more filters */
8656 state = IF_STATE_ACTION;
8662 if (state != IF_STATE_ACTION)
8672 free_filters_list(filters);
8679 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8685 * Since this is called in perf_ioctl() path, we're already holding
8688 lockdep_assert_held(&event->ctx->mutex);
8690 if (WARN_ON_ONCE(event->parent))
8693 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8695 goto fail_clear_files;
8697 ret = event->pmu->addr_filters_validate(&filters);
8699 goto fail_free_filters;
8701 /* remove existing filters, if any */
8702 perf_addr_filters_splice(event, &filters);
8704 /* install new filters */
8705 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8710 free_filters_list(&filters);
8713 event->addr_filters.nr_file_filters = 0;
8718 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8723 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8724 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8725 !has_addr_filter(event))
8728 filter_str = strndup_user(arg, PAGE_SIZE);
8729 if (IS_ERR(filter_str))
8730 return PTR_ERR(filter_str);
8732 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8733 event->attr.type == PERF_TYPE_TRACEPOINT)
8734 ret = ftrace_profile_set_filter(event, event->attr.config,
8736 else if (has_addr_filter(event))
8737 ret = perf_event_set_addr_filter(event, filter_str);
8744 * hrtimer based swevent callback
8747 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8749 enum hrtimer_restart ret = HRTIMER_RESTART;
8750 struct perf_sample_data data;
8751 struct pt_regs *regs;
8752 struct perf_event *event;
8755 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8757 if (event->state != PERF_EVENT_STATE_ACTIVE)
8758 return HRTIMER_NORESTART;
8760 event->pmu->read(event);
8762 perf_sample_data_init(&data, 0, event->hw.last_period);
8763 regs = get_irq_regs();
8765 if (regs && !perf_exclude_event(event, regs)) {
8766 if (!(event->attr.exclude_idle && is_idle_task(current)))
8767 if (__perf_event_overflow(event, 1, &data, regs))
8768 ret = HRTIMER_NORESTART;
8771 period = max_t(u64, 10000, event->hw.sample_period);
8772 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8777 static void perf_swevent_start_hrtimer(struct perf_event *event)
8779 struct hw_perf_event *hwc = &event->hw;
8782 if (!is_sampling_event(event))
8785 period = local64_read(&hwc->period_left);
8790 local64_set(&hwc->period_left, 0);
8792 period = max_t(u64, 10000, hwc->sample_period);
8794 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8795 HRTIMER_MODE_REL_PINNED);
8798 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8800 struct hw_perf_event *hwc = &event->hw;
8802 if (is_sampling_event(event)) {
8803 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8804 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8806 hrtimer_cancel(&hwc->hrtimer);
8810 static void perf_swevent_init_hrtimer(struct perf_event *event)
8812 struct hw_perf_event *hwc = &event->hw;
8814 if (!is_sampling_event(event))
8817 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8818 hwc->hrtimer.function = perf_swevent_hrtimer;
8821 * Since hrtimers have a fixed rate, we can do a static freq->period
8822 * mapping and avoid the whole period adjust feedback stuff.
8824 if (event->attr.freq) {
8825 long freq = event->attr.sample_freq;
8827 event->attr.sample_period = NSEC_PER_SEC / freq;
8828 hwc->sample_period = event->attr.sample_period;
8829 local64_set(&hwc->period_left, hwc->sample_period);
8830 hwc->last_period = hwc->sample_period;
8831 event->attr.freq = 0;
8836 * Software event: cpu wall time clock
8839 static void cpu_clock_event_update(struct perf_event *event)
8844 now = local_clock();
8845 prev = local64_xchg(&event->hw.prev_count, now);
8846 local64_add(now - prev, &event->count);
8849 static void cpu_clock_event_start(struct perf_event *event, int flags)
8851 local64_set(&event->hw.prev_count, local_clock());
8852 perf_swevent_start_hrtimer(event);
8855 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8857 perf_swevent_cancel_hrtimer(event);
8858 cpu_clock_event_update(event);
8861 static int cpu_clock_event_add(struct perf_event *event, int flags)
8863 if (flags & PERF_EF_START)
8864 cpu_clock_event_start(event, flags);
8865 perf_event_update_userpage(event);
8870 static void cpu_clock_event_del(struct perf_event *event, int flags)
8872 cpu_clock_event_stop(event, flags);
8875 static void cpu_clock_event_read(struct perf_event *event)
8877 cpu_clock_event_update(event);
8880 static int cpu_clock_event_init(struct perf_event *event)
8882 if (event->attr.type != PERF_TYPE_SOFTWARE)
8885 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8889 * no branch sampling for software events
8891 if (has_branch_stack(event))
8894 perf_swevent_init_hrtimer(event);
8899 static struct pmu perf_cpu_clock = {
8900 .task_ctx_nr = perf_sw_context,
8902 .capabilities = PERF_PMU_CAP_NO_NMI,
8904 .event_init = cpu_clock_event_init,
8905 .add = cpu_clock_event_add,
8906 .del = cpu_clock_event_del,
8907 .start = cpu_clock_event_start,
8908 .stop = cpu_clock_event_stop,
8909 .read = cpu_clock_event_read,
8913 * Software event: task time clock
8916 static void task_clock_event_update(struct perf_event *event, u64 now)
8921 prev = local64_xchg(&event->hw.prev_count, now);
8923 local64_add(delta, &event->count);
8926 static void task_clock_event_start(struct perf_event *event, int flags)
8928 local64_set(&event->hw.prev_count, event->ctx->time);
8929 perf_swevent_start_hrtimer(event);
8932 static void task_clock_event_stop(struct perf_event *event, int flags)
8934 perf_swevent_cancel_hrtimer(event);
8935 task_clock_event_update(event, event->ctx->time);
8938 static int task_clock_event_add(struct perf_event *event, int flags)
8940 if (flags & PERF_EF_START)
8941 task_clock_event_start(event, flags);
8942 perf_event_update_userpage(event);
8947 static void task_clock_event_del(struct perf_event *event, int flags)
8949 task_clock_event_stop(event, PERF_EF_UPDATE);
8952 static void task_clock_event_read(struct perf_event *event)
8954 u64 now = perf_clock();
8955 u64 delta = now - event->ctx->timestamp;
8956 u64 time = event->ctx->time + delta;
8958 task_clock_event_update(event, time);
8961 static int task_clock_event_init(struct perf_event *event)
8963 if (event->attr.type != PERF_TYPE_SOFTWARE)
8966 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8970 * no branch sampling for software events
8972 if (has_branch_stack(event))
8975 perf_swevent_init_hrtimer(event);
8980 static struct pmu perf_task_clock = {
8981 .task_ctx_nr = perf_sw_context,
8983 .capabilities = PERF_PMU_CAP_NO_NMI,
8985 .event_init = task_clock_event_init,
8986 .add = task_clock_event_add,
8987 .del = task_clock_event_del,
8988 .start = task_clock_event_start,
8989 .stop = task_clock_event_stop,
8990 .read = task_clock_event_read,
8993 static void perf_pmu_nop_void(struct pmu *pmu)
8997 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9001 static int perf_pmu_nop_int(struct pmu *pmu)
9006 static int perf_event_nop_int(struct perf_event *event, u64 value)
9011 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9013 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9015 __this_cpu_write(nop_txn_flags, flags);
9017 if (flags & ~PERF_PMU_TXN_ADD)
9020 perf_pmu_disable(pmu);
9023 static int perf_pmu_commit_txn(struct pmu *pmu)
9025 unsigned int flags = __this_cpu_read(nop_txn_flags);
9027 __this_cpu_write(nop_txn_flags, 0);
9029 if (flags & ~PERF_PMU_TXN_ADD)
9032 perf_pmu_enable(pmu);
9036 static void perf_pmu_cancel_txn(struct pmu *pmu)
9038 unsigned int flags = __this_cpu_read(nop_txn_flags);
9040 __this_cpu_write(nop_txn_flags, 0);
9042 if (flags & ~PERF_PMU_TXN_ADD)
9045 perf_pmu_enable(pmu);
9048 static int perf_event_idx_default(struct perf_event *event)
9054 * Ensures all contexts with the same task_ctx_nr have the same
9055 * pmu_cpu_context too.
9057 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9064 list_for_each_entry(pmu, &pmus, entry) {
9065 if (pmu->task_ctx_nr == ctxn)
9066 return pmu->pmu_cpu_context;
9072 static void free_pmu_context(struct pmu *pmu)
9075 * Static contexts such as perf_sw_context have a global lifetime
9076 * and may be shared between different PMUs. Avoid freeing them
9077 * when a single PMU is going away.
9079 if (pmu->task_ctx_nr > perf_invalid_context)
9082 free_percpu(pmu->pmu_cpu_context);
9086 * Let userspace know that this PMU supports address range filtering:
9088 static ssize_t nr_addr_filters_show(struct device *dev,
9089 struct device_attribute *attr,
9092 struct pmu *pmu = dev_get_drvdata(dev);
9094 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9096 DEVICE_ATTR_RO(nr_addr_filters);
9098 static struct idr pmu_idr;
9101 type_show(struct device *dev, struct device_attribute *attr, char *page)
9103 struct pmu *pmu = dev_get_drvdata(dev);
9105 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9107 static DEVICE_ATTR_RO(type);
9110 perf_event_mux_interval_ms_show(struct device *dev,
9111 struct device_attribute *attr,
9114 struct pmu *pmu = dev_get_drvdata(dev);
9116 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9119 static DEFINE_MUTEX(mux_interval_mutex);
9122 perf_event_mux_interval_ms_store(struct device *dev,
9123 struct device_attribute *attr,
9124 const char *buf, size_t count)
9126 struct pmu *pmu = dev_get_drvdata(dev);
9127 int timer, cpu, ret;
9129 ret = kstrtoint(buf, 0, &timer);
9136 /* same value, noting to do */
9137 if (timer == pmu->hrtimer_interval_ms)
9140 mutex_lock(&mux_interval_mutex);
9141 pmu->hrtimer_interval_ms = timer;
9143 /* update all cpuctx for this PMU */
9145 for_each_online_cpu(cpu) {
9146 struct perf_cpu_context *cpuctx;
9147 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9148 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9150 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpuctx);
9153 mutex_unlock(&mux_interval_mutex);
9157 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9159 static struct attribute *pmu_dev_attrs[] = {
9160 &dev_attr_type.attr,
9161 &dev_attr_perf_event_mux_interval_ms.attr,
9164 ATTRIBUTE_GROUPS(pmu_dev);
9166 static int pmu_bus_running;
9167 static struct bus_type pmu_bus = {
9168 .name = "event_source",
9169 .dev_groups = pmu_dev_groups,
9172 static void pmu_dev_release(struct device *dev)
9177 static int pmu_dev_alloc(struct pmu *pmu)
9181 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9185 pmu->dev->groups = pmu->attr_groups;
9186 device_initialize(pmu->dev);
9188 dev_set_drvdata(pmu->dev, pmu);
9189 pmu->dev->bus = &pmu_bus;
9190 pmu->dev->release = pmu_dev_release;
9192 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9196 ret = device_add(pmu->dev);
9200 /* For PMUs with address filters, throw in an extra attribute: */
9201 if (pmu->nr_addr_filters)
9202 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9211 device_del(pmu->dev);
9214 put_device(pmu->dev);
9218 static struct lock_class_key cpuctx_mutex;
9219 static struct lock_class_key cpuctx_lock;
9221 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9225 mutex_lock(&pmus_lock);
9227 pmu->pmu_disable_count = alloc_percpu(int);
9228 if (!pmu->pmu_disable_count)
9237 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9245 if (pmu_bus_running) {
9246 ret = pmu_dev_alloc(pmu);
9252 if (pmu->task_ctx_nr == perf_hw_context) {
9253 static int hw_context_taken = 0;
9256 * Other than systems with heterogeneous CPUs, it never makes
9257 * sense for two PMUs to share perf_hw_context. PMUs which are
9258 * uncore must use perf_invalid_context.
9260 if (WARN_ON_ONCE(hw_context_taken &&
9261 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9262 pmu->task_ctx_nr = perf_invalid_context;
9264 hw_context_taken = 1;
9267 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9268 if (pmu->pmu_cpu_context)
9269 goto got_cpu_context;
9272 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9273 if (!pmu->pmu_cpu_context)
9276 for_each_possible_cpu(cpu) {
9277 struct perf_cpu_context *cpuctx;
9279 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9280 __perf_event_init_context(&cpuctx->ctx);
9281 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9282 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9283 cpuctx->ctx.pmu = pmu;
9284 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9286 __perf_mux_hrtimer_init(cpuctx, cpu);
9290 if (!pmu->start_txn) {
9291 if (pmu->pmu_enable) {
9293 * If we have pmu_enable/pmu_disable calls, install
9294 * transaction stubs that use that to try and batch
9295 * hardware accesses.
9297 pmu->start_txn = perf_pmu_start_txn;
9298 pmu->commit_txn = perf_pmu_commit_txn;
9299 pmu->cancel_txn = perf_pmu_cancel_txn;
9301 pmu->start_txn = perf_pmu_nop_txn;
9302 pmu->commit_txn = perf_pmu_nop_int;
9303 pmu->cancel_txn = perf_pmu_nop_void;
9307 if (!pmu->pmu_enable) {
9308 pmu->pmu_enable = perf_pmu_nop_void;
9309 pmu->pmu_disable = perf_pmu_nop_void;
9312 if (!pmu->check_period)
9313 pmu->check_period = perf_event_nop_int;
9315 if (!pmu->event_idx)
9316 pmu->event_idx = perf_event_idx_default;
9318 list_add_rcu(&pmu->entry, &pmus);
9319 atomic_set(&pmu->exclusive_cnt, 0);
9322 mutex_unlock(&pmus_lock);
9327 device_del(pmu->dev);
9328 put_device(pmu->dev);
9331 if (pmu->type >= PERF_TYPE_MAX)
9332 idr_remove(&pmu_idr, pmu->type);
9335 free_percpu(pmu->pmu_disable_count);
9338 EXPORT_SYMBOL_GPL(perf_pmu_register);
9340 void perf_pmu_unregister(struct pmu *pmu)
9342 mutex_lock(&pmus_lock);
9343 list_del_rcu(&pmu->entry);
9346 * We dereference the pmu list under both SRCU and regular RCU, so
9347 * synchronize against both of those.
9349 synchronize_srcu(&pmus_srcu);
9352 free_percpu(pmu->pmu_disable_count);
9353 if (pmu->type >= PERF_TYPE_MAX)
9354 idr_remove(&pmu_idr, pmu->type);
9355 if (pmu_bus_running) {
9356 if (pmu->nr_addr_filters)
9357 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9358 device_del(pmu->dev);
9359 put_device(pmu->dev);
9361 free_pmu_context(pmu);
9362 mutex_unlock(&pmus_lock);
9364 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9366 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9368 struct perf_event_context *ctx = NULL;
9371 if (!try_module_get(pmu->module))
9374 if (event->group_leader != event) {
9376 * This ctx->mutex can nest when we're called through
9377 * inheritance. See the perf_event_ctx_lock_nested() comment.
9379 ctx = perf_event_ctx_lock_nested(event->group_leader,
9380 SINGLE_DEPTH_NESTING);
9385 ret = pmu->event_init(event);
9388 perf_event_ctx_unlock(event->group_leader, ctx);
9391 module_put(pmu->module);
9396 static struct pmu *perf_init_event(struct perf_event *event)
9402 idx = srcu_read_lock(&pmus_srcu);
9404 /* Try parent's PMU first: */
9405 if (event->parent && event->parent->pmu) {
9406 pmu = event->parent->pmu;
9407 ret = perf_try_init_event(pmu, event);
9413 pmu = idr_find(&pmu_idr, event->attr.type);
9416 ret = perf_try_init_event(pmu, event);
9422 list_for_each_entry_rcu(pmu, &pmus, entry) {
9423 ret = perf_try_init_event(pmu, event);
9427 if (ret != -ENOENT) {
9432 pmu = ERR_PTR(-ENOENT);
9434 srcu_read_unlock(&pmus_srcu, idx);
9439 static void attach_sb_event(struct perf_event *event)
9441 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9443 raw_spin_lock(&pel->lock);
9444 list_add_rcu(&event->sb_list, &pel->list);
9445 raw_spin_unlock(&pel->lock);
9449 * We keep a list of all !task (and therefore per-cpu) events
9450 * that need to receive side-band records.
9452 * This avoids having to scan all the various PMU per-cpu contexts
9455 static void account_pmu_sb_event(struct perf_event *event)
9457 if (is_sb_event(event))
9458 attach_sb_event(event);
9461 static void account_event_cpu(struct perf_event *event, int cpu)
9466 if (is_cgroup_event(event))
9467 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9470 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9471 static void account_freq_event_nohz(void)
9473 #ifdef CONFIG_NO_HZ_FULL
9474 /* Lock so we don't race with concurrent unaccount */
9475 spin_lock(&nr_freq_lock);
9476 if (atomic_inc_return(&nr_freq_events) == 1)
9477 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9478 spin_unlock(&nr_freq_lock);
9482 static void account_freq_event(void)
9484 if (tick_nohz_full_enabled())
9485 account_freq_event_nohz();
9487 atomic_inc(&nr_freq_events);
9491 static void account_event(struct perf_event *event)
9498 if (event->attach_state & PERF_ATTACH_TASK)
9500 if (event->attr.mmap || event->attr.mmap_data)
9501 atomic_inc(&nr_mmap_events);
9502 if (event->attr.comm)
9503 atomic_inc(&nr_comm_events);
9504 if (event->attr.namespaces)
9505 atomic_inc(&nr_namespaces_events);
9506 if (event->attr.task)
9507 atomic_inc(&nr_task_events);
9508 if (event->attr.freq)
9509 account_freq_event();
9510 if (event->attr.context_switch) {
9511 atomic_inc(&nr_switch_events);
9514 if (has_branch_stack(event))
9516 if (is_cgroup_event(event))
9520 if (atomic_inc_not_zero(&perf_sched_count))
9523 mutex_lock(&perf_sched_mutex);
9524 if (!atomic_read(&perf_sched_count)) {
9525 static_branch_enable(&perf_sched_events);
9527 * Guarantee that all CPUs observe they key change and
9528 * call the perf scheduling hooks before proceeding to
9529 * install events that need them.
9531 synchronize_sched();
9534 * Now that we have waited for the sync_sched(), allow further
9535 * increments to by-pass the mutex.
9537 atomic_inc(&perf_sched_count);
9538 mutex_unlock(&perf_sched_mutex);
9542 account_event_cpu(event, event->cpu);
9544 account_pmu_sb_event(event);
9548 * Allocate and initialize a event structure
9550 static struct perf_event *
9551 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9552 struct task_struct *task,
9553 struct perf_event *group_leader,
9554 struct perf_event *parent_event,
9555 perf_overflow_handler_t overflow_handler,
9556 void *context, int cgroup_fd)
9559 struct perf_event *event;
9560 struct hw_perf_event *hwc;
9563 if ((unsigned)cpu >= nr_cpu_ids) {
9564 if (!task || cpu != -1)
9565 return ERR_PTR(-EINVAL);
9568 event = kzalloc(sizeof(*event), GFP_KERNEL);
9570 return ERR_PTR(-ENOMEM);
9573 * Single events are their own group leaders, with an
9574 * empty sibling list:
9577 group_leader = event;
9579 mutex_init(&event->child_mutex);
9580 INIT_LIST_HEAD(&event->child_list);
9582 INIT_LIST_HEAD(&event->group_entry);
9583 INIT_LIST_HEAD(&event->event_entry);
9584 INIT_LIST_HEAD(&event->sibling_list);
9585 INIT_LIST_HEAD(&event->rb_entry);
9586 INIT_LIST_HEAD(&event->active_entry);
9587 INIT_LIST_HEAD(&event->addr_filters.list);
9588 INIT_HLIST_NODE(&event->hlist_entry);
9591 init_waitqueue_head(&event->waitq);
9592 init_irq_work(&event->pending, perf_pending_event);
9594 mutex_init(&event->mmap_mutex);
9595 raw_spin_lock_init(&event->addr_filters.lock);
9597 atomic_long_set(&event->refcount, 1);
9599 event->attr = *attr;
9600 event->group_leader = group_leader;
9604 event->parent = parent_event;
9606 event->ns = get_pid_ns(task_active_pid_ns(current));
9607 event->id = atomic64_inc_return(&perf_event_id);
9609 event->state = PERF_EVENT_STATE_INACTIVE;
9612 event->attach_state = PERF_ATTACH_TASK;
9614 * XXX pmu::event_init needs to know what task to account to
9615 * and we cannot use the ctx information because we need the
9616 * pmu before we get a ctx.
9618 get_task_struct(task);
9619 event->hw.target = task;
9622 event->clock = &local_clock;
9624 event->clock = parent_event->clock;
9626 if (!overflow_handler && parent_event) {
9627 overflow_handler = parent_event->overflow_handler;
9628 context = parent_event->overflow_handler_context;
9629 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9630 if (overflow_handler == bpf_overflow_handler) {
9631 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9634 err = PTR_ERR(prog);
9638 event->orig_overflow_handler =
9639 parent_event->orig_overflow_handler;
9644 if (overflow_handler) {
9645 event->overflow_handler = overflow_handler;
9646 event->overflow_handler_context = context;
9647 } else if (is_write_backward(event)){
9648 event->overflow_handler = perf_event_output_backward;
9649 event->overflow_handler_context = NULL;
9651 event->overflow_handler = perf_event_output_forward;
9652 event->overflow_handler_context = NULL;
9655 perf_event__state_init(event);
9660 hwc->sample_period = attr->sample_period;
9661 if (attr->freq && attr->sample_freq)
9662 hwc->sample_period = 1;
9663 hwc->last_period = hwc->sample_period;
9665 local64_set(&hwc->period_left, hwc->sample_period);
9668 * We currently do not support PERF_SAMPLE_READ on inherited events.
9669 * See perf_output_read().
9671 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9674 if (!has_branch_stack(event))
9675 event->attr.branch_sample_type = 0;
9677 if (cgroup_fd != -1) {
9678 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9683 pmu = perf_init_event(event);
9689 err = exclusive_event_init(event);
9693 if (has_addr_filter(event)) {
9694 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9695 sizeof(unsigned long),
9697 if (!event->addr_filters_offs) {
9702 /* force hw sync on the address filters */
9703 event->addr_filters_gen = 1;
9706 if (!event->parent) {
9707 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9708 err = get_callchain_buffers(attr->sample_max_stack);
9710 goto err_addr_filters;
9714 /* symmetric to unaccount_event() in _free_event() */
9715 account_event(event);
9720 kfree(event->addr_filters_offs);
9723 exclusive_event_destroy(event);
9727 event->destroy(event);
9728 module_put(pmu->module);
9730 if (is_cgroup_event(event))
9731 perf_detach_cgroup(event);
9733 put_pid_ns(event->ns);
9734 if (event->hw.target)
9735 put_task_struct(event->hw.target);
9738 return ERR_PTR(err);
9741 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9742 struct perf_event_attr *attr)
9747 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9751 * zero the full structure, so that a short copy will be nice.
9753 memset(attr, 0, sizeof(*attr));
9755 ret = get_user(size, &uattr->size);
9759 if (size > PAGE_SIZE) /* silly large */
9762 if (!size) /* abi compat */
9763 size = PERF_ATTR_SIZE_VER0;
9765 if (size < PERF_ATTR_SIZE_VER0)
9769 * If we're handed a bigger struct than we know of,
9770 * ensure all the unknown bits are 0 - i.e. new
9771 * user-space does not rely on any kernel feature
9772 * extensions we dont know about yet.
9774 if (size > sizeof(*attr)) {
9775 unsigned char __user *addr;
9776 unsigned char __user *end;
9779 addr = (void __user *)uattr + sizeof(*attr);
9780 end = (void __user *)uattr + size;
9782 for (; addr < end; addr++) {
9783 ret = get_user(val, addr);
9789 size = sizeof(*attr);
9792 ret = copy_from_user(attr, uattr, size);
9798 if (attr->__reserved_1)
9801 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9804 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9807 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9808 u64 mask = attr->branch_sample_type;
9810 /* only using defined bits */
9811 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9814 /* at least one branch bit must be set */
9815 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9818 /* propagate priv level, when not set for branch */
9819 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9821 /* exclude_kernel checked on syscall entry */
9822 if (!attr->exclude_kernel)
9823 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9825 if (!attr->exclude_user)
9826 mask |= PERF_SAMPLE_BRANCH_USER;
9828 if (!attr->exclude_hv)
9829 mask |= PERF_SAMPLE_BRANCH_HV;
9831 * adjust user setting (for HW filter setup)
9833 attr->branch_sample_type = mask;
9835 /* privileged levels capture (kernel, hv): check permissions */
9836 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9837 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9841 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9842 ret = perf_reg_validate(attr->sample_regs_user);
9847 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9848 if (!arch_perf_have_user_stack_dump())
9852 * We have __u32 type for the size, but so far
9853 * we can only use __u16 as maximum due to the
9854 * __u16 sample size limit.
9856 if (attr->sample_stack_user >= USHRT_MAX)
9858 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9862 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9863 ret = perf_reg_validate(attr->sample_regs_intr);
9868 put_user(sizeof(*attr), &uattr->size);
9873 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9879 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9883 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9885 struct ring_buffer *rb = NULL;
9888 if (!output_event) {
9889 mutex_lock(&event->mmap_mutex);
9893 /* don't allow circular references */
9894 if (event == output_event)
9898 * Don't allow cross-cpu buffers
9900 if (output_event->cpu != event->cpu)
9904 * If its not a per-cpu rb, it must be the same task.
9906 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
9910 * Mixing clocks in the same buffer is trouble you don't need.
9912 if (output_event->clock != event->clock)
9916 * Either writing ring buffer from beginning or from end.
9917 * Mixing is not allowed.
9919 if (is_write_backward(output_event) != is_write_backward(event))
9923 * If both events generate aux data, they must be on the same PMU
9925 if (has_aux(event) && has_aux(output_event) &&
9926 event->pmu != output_event->pmu)
9930 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
9931 * output_event is already on rb->event_list, and the list iteration
9932 * restarts after every removal, it is guaranteed this new event is
9933 * observed *OR* if output_event is already removed, it's guaranteed we
9934 * observe !rb->mmap_count.
9936 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
9938 /* Can't redirect output if we've got an active mmap() */
9939 if (atomic_read(&event->mmap_count))
9943 /* get the rb we want to redirect to */
9944 rb = ring_buffer_get(output_event);
9948 /* did we race against perf_mmap_close() */
9949 if (!atomic_read(&rb->mmap_count)) {
9950 ring_buffer_put(rb);
9955 ring_buffer_attach(event, rb);
9959 mutex_unlock(&event->mmap_mutex);
9961 mutex_unlock(&output_event->mmap_mutex);
9967 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9969 bool nmi_safe = false;
9972 case CLOCK_MONOTONIC:
9973 event->clock = &ktime_get_mono_fast_ns;
9977 case CLOCK_MONOTONIC_RAW:
9978 event->clock = &ktime_get_raw_fast_ns;
9982 case CLOCK_REALTIME:
9983 event->clock = &ktime_get_real_ns;
9986 case CLOCK_BOOTTIME:
9987 event->clock = &ktime_get_boot_ns;
9991 event->clock = &ktime_get_tai_ns;
9998 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10005 * Variation on perf_event_ctx_lock_nested(), except we take two context
10008 static struct perf_event_context *
10009 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10010 struct perf_event_context *ctx)
10012 struct perf_event_context *gctx;
10016 gctx = READ_ONCE(group_leader->ctx);
10017 if (!atomic_inc_not_zero(&gctx->refcount)) {
10023 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10025 if (group_leader->ctx != gctx) {
10026 mutex_unlock(&ctx->mutex);
10027 mutex_unlock(&gctx->mutex);
10036 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10038 * @attr_uptr: event_id type attributes for monitoring/sampling
10041 * @group_fd: group leader event fd
10043 SYSCALL_DEFINE5(perf_event_open,
10044 struct perf_event_attr __user *, attr_uptr,
10045 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10047 struct perf_event *group_leader = NULL, *output_event = NULL;
10048 struct perf_event *event, *sibling;
10049 struct perf_event_attr attr;
10050 struct perf_event_context *ctx, *gctx;
10051 struct file *event_file = NULL;
10052 struct fd group = {NULL, 0};
10053 struct task_struct *task = NULL;
10056 int move_group = 0;
10058 int f_flags = O_RDWR;
10059 int cgroup_fd = -1;
10061 /* for future expandability... */
10062 if (flags & ~PERF_FLAG_ALL)
10065 err = perf_copy_attr(attr_uptr, &attr);
10069 if (!attr.exclude_kernel) {
10070 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10074 if (attr.namespaces) {
10075 if (!capable(CAP_SYS_ADMIN))
10080 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10083 if (attr.sample_period & (1ULL << 63))
10087 /* Only privileged users can get physical addresses */
10088 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10089 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10092 if (!attr.sample_max_stack)
10093 attr.sample_max_stack = sysctl_perf_event_max_stack;
10096 * In cgroup mode, the pid argument is used to pass the fd
10097 * opened to the cgroup directory in cgroupfs. The cpu argument
10098 * designates the cpu on which to monitor threads from that
10101 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10104 if (flags & PERF_FLAG_FD_CLOEXEC)
10105 f_flags |= O_CLOEXEC;
10107 event_fd = get_unused_fd_flags(f_flags);
10111 if (group_fd != -1) {
10112 err = perf_fget_light(group_fd, &group);
10115 group_leader = group.file->private_data;
10116 if (flags & PERF_FLAG_FD_OUTPUT)
10117 output_event = group_leader;
10118 if (flags & PERF_FLAG_FD_NO_GROUP)
10119 group_leader = NULL;
10122 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10123 task = find_lively_task_by_vpid(pid);
10124 if (IS_ERR(task)) {
10125 err = PTR_ERR(task);
10130 if (task && group_leader &&
10131 group_leader->attr.inherit != attr.inherit) {
10137 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10142 * Reuse ptrace permission checks for now.
10144 * We must hold cred_guard_mutex across this and any potential
10145 * perf_install_in_context() call for this new event to
10146 * serialize against exec() altering our credentials (and the
10147 * perf_event_exit_task() that could imply).
10150 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10154 if (flags & PERF_FLAG_PID_CGROUP)
10157 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10158 NULL, NULL, cgroup_fd);
10159 if (IS_ERR(event)) {
10160 err = PTR_ERR(event);
10164 if (is_sampling_event(event)) {
10165 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10172 * Special case software events and allow them to be part of
10173 * any hardware group.
10177 if (attr.use_clockid) {
10178 err = perf_event_set_clock(event, attr.clockid);
10183 if (pmu->task_ctx_nr == perf_sw_context)
10184 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10186 if (group_leader &&
10187 (is_software_event(event) != is_software_event(group_leader))) {
10188 if (is_software_event(event)) {
10190 * If event and group_leader are not both a software
10191 * event, and event is, then group leader is not.
10193 * Allow the addition of software events to !software
10194 * groups, this is safe because software events never
10195 * fail to schedule.
10197 pmu = group_leader->pmu;
10198 } else if (is_software_event(group_leader) &&
10199 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10201 * In case the group is a pure software group, and we
10202 * try to add a hardware event, move the whole group to
10203 * the hardware context.
10210 * Get the target context (task or percpu):
10212 ctx = find_get_context(pmu, task, event);
10214 err = PTR_ERR(ctx);
10218 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10224 * Look up the group leader (we will attach this event to it):
10226 if (group_leader) {
10230 * Do not allow a recursive hierarchy (this new sibling
10231 * becoming part of another group-sibling):
10233 if (group_leader->group_leader != group_leader)
10236 /* All events in a group should have the same clock */
10237 if (group_leader->clock != event->clock)
10241 * Make sure we're both events for the same CPU;
10242 * grouping events for different CPUs is broken; since
10243 * you can never concurrently schedule them anyhow.
10245 if (group_leader->cpu != event->cpu)
10249 * Make sure we're both on the same task, or both
10252 if (group_leader->ctx->task != ctx->task)
10256 * Do not allow to attach to a group in a different task
10257 * or CPU context. If we're moving SW events, we'll fix
10258 * this up later, so allow that.
10260 * Racy, not holding group_leader->ctx->mutex, see comment with
10261 * perf_event_ctx_lock().
10263 if (!move_group && group_leader->ctx != ctx)
10267 * Only a group leader can be exclusive or pinned
10269 if (attr.exclusive || attr.pinned)
10273 if (output_event) {
10274 err = perf_event_set_output(event, output_event);
10279 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10281 if (IS_ERR(event_file)) {
10282 err = PTR_ERR(event_file);
10288 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10290 if (gctx->task == TASK_TOMBSTONE) {
10296 * Check if we raced against another sys_perf_event_open() call
10297 * moving the software group underneath us.
10299 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10301 * If someone moved the group out from under us, check
10302 * if this new event wound up on the same ctx, if so
10303 * its the regular !move_group case, otherwise fail.
10309 perf_event_ctx_unlock(group_leader, gctx);
10311 goto not_move_group;
10315 mutex_lock(&ctx->mutex);
10318 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
10319 * see the group_leader && !move_group test earlier.
10321 if (group_leader && group_leader->ctx != ctx) {
10328 if (ctx->task == TASK_TOMBSTONE) {
10333 if (!perf_event_validate_size(event)) {
10340 * Check if the @cpu we're creating an event for is online.
10342 * We use the perf_cpu_context::ctx::mutex to serialize against
10343 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10345 struct perf_cpu_context *cpuctx =
10346 container_of(ctx, struct perf_cpu_context, ctx);
10348 if (!cpuctx->online) {
10356 * Must be under the same ctx::mutex as perf_install_in_context(),
10357 * because we need to serialize with concurrent event creation.
10359 if (!exclusive_event_installable(event, ctx)) {
10360 /* exclusive and group stuff are assumed mutually exclusive */
10361 WARN_ON_ONCE(move_group);
10367 WARN_ON_ONCE(ctx->parent_ctx);
10370 * This is the point on no return; we cannot fail hereafter. This is
10371 * where we start modifying current state.
10376 * See perf_event_ctx_lock() for comments on the details
10377 * of swizzling perf_event::ctx.
10379 perf_remove_from_context(group_leader, 0);
10382 list_for_each_entry(sibling, &group_leader->sibling_list,
10384 perf_remove_from_context(sibling, 0);
10389 * Wait for everybody to stop referencing the events through
10390 * the old lists, before installing it on new lists.
10395 * Install the group siblings before the group leader.
10397 * Because a group leader will try and install the entire group
10398 * (through the sibling list, which is still in-tact), we can
10399 * end up with siblings installed in the wrong context.
10401 * By installing siblings first we NO-OP because they're not
10402 * reachable through the group lists.
10404 list_for_each_entry(sibling, &group_leader->sibling_list,
10406 perf_event__state_init(sibling);
10407 perf_install_in_context(ctx, sibling, sibling->cpu);
10412 * Removing from the context ends up with disabled
10413 * event. What we want here is event in the initial
10414 * startup state, ready to be add into new context.
10416 perf_event__state_init(group_leader);
10417 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10422 * Precalculate sample_data sizes; do while holding ctx::mutex such
10423 * that we're serialized against further additions and before
10424 * perf_install_in_context() which is the point the event is active and
10425 * can use these values.
10427 perf_event__header_size(event);
10428 perf_event__id_header_size(event);
10430 event->owner = current;
10432 perf_install_in_context(ctx, event, event->cpu);
10433 perf_unpin_context(ctx);
10436 perf_event_ctx_unlock(group_leader, gctx);
10437 mutex_unlock(&ctx->mutex);
10440 mutex_unlock(&task->signal->cred_guard_mutex);
10441 put_task_struct(task);
10444 mutex_lock(¤t->perf_event_mutex);
10445 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10446 mutex_unlock(¤t->perf_event_mutex);
10449 * Drop the reference on the group_event after placing the
10450 * new event on the sibling_list. This ensures destruction
10451 * of the group leader will find the pointer to itself in
10452 * perf_group_detach().
10455 fd_install(event_fd, event_file);
10460 perf_event_ctx_unlock(group_leader, gctx);
10461 mutex_unlock(&ctx->mutex);
10465 perf_unpin_context(ctx);
10469 * If event_file is set, the fput() above will have called ->release()
10470 * and that will take care of freeing the event.
10476 mutex_unlock(&task->signal->cred_guard_mutex);
10479 put_task_struct(task);
10483 put_unused_fd(event_fd);
10488 * perf_event_create_kernel_counter
10490 * @attr: attributes of the counter to create
10491 * @cpu: cpu in which the counter is bound
10492 * @task: task to profile (NULL for percpu)
10494 struct perf_event *
10495 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10496 struct task_struct *task,
10497 perf_overflow_handler_t overflow_handler,
10500 struct perf_event_context *ctx;
10501 struct perf_event *event;
10505 * Get the target context (task or percpu):
10508 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10509 overflow_handler, context, -1);
10510 if (IS_ERR(event)) {
10511 err = PTR_ERR(event);
10515 /* Mark owner so we could distinguish it from user events. */
10516 event->owner = TASK_TOMBSTONE;
10518 ctx = find_get_context(event->pmu, task, event);
10520 err = PTR_ERR(ctx);
10524 WARN_ON_ONCE(ctx->parent_ctx);
10525 mutex_lock(&ctx->mutex);
10526 if (ctx->task == TASK_TOMBSTONE) {
10533 * Check if the @cpu we're creating an event for is online.
10535 * We use the perf_cpu_context::ctx::mutex to serialize against
10536 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10538 struct perf_cpu_context *cpuctx =
10539 container_of(ctx, struct perf_cpu_context, ctx);
10540 if (!cpuctx->online) {
10546 if (!exclusive_event_installable(event, ctx)) {
10551 perf_install_in_context(ctx, event, event->cpu);
10552 perf_unpin_context(ctx);
10553 mutex_unlock(&ctx->mutex);
10558 mutex_unlock(&ctx->mutex);
10559 perf_unpin_context(ctx);
10564 return ERR_PTR(err);
10566 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10568 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10570 struct perf_event_context *src_ctx;
10571 struct perf_event_context *dst_ctx;
10572 struct perf_event *event, *tmp;
10575 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10576 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10579 * See perf_event_ctx_lock() for comments on the details
10580 * of swizzling perf_event::ctx.
10582 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10583 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10585 perf_remove_from_context(event, 0);
10586 unaccount_event_cpu(event, src_cpu);
10588 list_add(&event->migrate_entry, &events);
10592 * Wait for the events to quiesce before re-instating them.
10597 * Re-instate events in 2 passes.
10599 * Skip over group leaders and only install siblings on this first
10600 * pass, siblings will not get enabled without a leader, however a
10601 * leader will enable its siblings, even if those are still on the old
10604 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10605 if (event->group_leader == event)
10608 list_del(&event->migrate_entry);
10609 if (event->state >= PERF_EVENT_STATE_OFF)
10610 event->state = PERF_EVENT_STATE_INACTIVE;
10611 account_event_cpu(event, dst_cpu);
10612 perf_install_in_context(dst_ctx, event, dst_cpu);
10617 * Once all the siblings are setup properly, install the group leaders
10620 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10621 list_del(&event->migrate_entry);
10622 if (event->state >= PERF_EVENT_STATE_OFF)
10623 event->state = PERF_EVENT_STATE_INACTIVE;
10624 account_event_cpu(event, dst_cpu);
10625 perf_install_in_context(dst_ctx, event, dst_cpu);
10628 mutex_unlock(&dst_ctx->mutex);
10629 mutex_unlock(&src_ctx->mutex);
10631 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10633 static void sync_child_event(struct perf_event *child_event,
10634 struct task_struct *child)
10636 struct perf_event *parent_event = child_event->parent;
10639 if (child_event->attr.inherit_stat)
10640 perf_event_read_event(child_event, child);
10642 child_val = perf_event_count(child_event);
10645 * Add back the child's count to the parent's count:
10647 atomic64_add(child_val, &parent_event->child_count);
10648 atomic64_add(child_event->total_time_enabled,
10649 &parent_event->child_total_time_enabled);
10650 atomic64_add(child_event->total_time_running,
10651 &parent_event->child_total_time_running);
10655 perf_event_exit_event(struct perf_event *child_event,
10656 struct perf_event_context *child_ctx,
10657 struct task_struct *child)
10659 struct perf_event *parent_event = child_event->parent;
10662 * Do not destroy the 'original' grouping; because of the context
10663 * switch optimization the original events could've ended up in a
10664 * random child task.
10666 * If we were to destroy the original group, all group related
10667 * operations would cease to function properly after this random
10670 * Do destroy all inherited groups, we don't care about those
10671 * and being thorough is better.
10673 raw_spin_lock_irq(&child_ctx->lock);
10674 WARN_ON_ONCE(child_ctx->is_active);
10677 perf_group_detach(child_event);
10678 list_del_event(child_event, child_ctx);
10679 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10680 raw_spin_unlock_irq(&child_ctx->lock);
10683 * Parent events are governed by their filedesc, retain them.
10685 if (!parent_event) {
10686 perf_event_wakeup(child_event);
10690 * Child events can be cleaned up.
10693 sync_child_event(child_event, child);
10696 * Remove this event from the parent's list
10698 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10699 mutex_lock(&parent_event->child_mutex);
10700 list_del_init(&child_event->child_list);
10701 mutex_unlock(&parent_event->child_mutex);
10704 * Kick perf_poll() for is_event_hup().
10706 perf_event_wakeup(parent_event);
10707 free_event(child_event);
10708 put_event(parent_event);
10711 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10713 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10714 struct perf_event *child_event, *next;
10716 WARN_ON_ONCE(child != current);
10718 child_ctx = perf_pin_task_context(child, ctxn);
10723 * In order to reduce the amount of tricky in ctx tear-down, we hold
10724 * ctx::mutex over the entire thing. This serializes against almost
10725 * everything that wants to access the ctx.
10727 * The exception is sys_perf_event_open() /
10728 * perf_event_create_kernel_count() which does find_get_context()
10729 * without ctx::mutex (it cannot because of the move_group double mutex
10730 * lock thing). See the comments in perf_install_in_context().
10732 mutex_lock(&child_ctx->mutex);
10735 * In a single ctx::lock section, de-schedule the events and detach the
10736 * context from the task such that we cannot ever get it scheduled back
10739 raw_spin_lock_irq(&child_ctx->lock);
10740 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10743 * Now that the context is inactive, destroy the task <-> ctx relation
10744 * and mark the context dead.
10746 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10747 put_ctx(child_ctx); /* cannot be last */
10748 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10749 put_task_struct(current); /* cannot be last */
10751 clone_ctx = unclone_ctx(child_ctx);
10752 raw_spin_unlock_irq(&child_ctx->lock);
10755 put_ctx(clone_ctx);
10758 * Report the task dead after unscheduling the events so that we
10759 * won't get any samples after PERF_RECORD_EXIT. We can however still
10760 * get a few PERF_RECORD_READ events.
10762 perf_event_task(child, child_ctx, 0);
10764 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10765 perf_event_exit_event(child_event, child_ctx, child);
10767 mutex_unlock(&child_ctx->mutex);
10769 put_ctx(child_ctx);
10773 * When a child task exits, feed back event values to parent events.
10775 * Can be called with cred_guard_mutex held when called from
10776 * install_exec_creds().
10778 void perf_event_exit_task(struct task_struct *child)
10780 struct perf_event *event, *tmp;
10783 mutex_lock(&child->perf_event_mutex);
10784 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10786 list_del_init(&event->owner_entry);
10789 * Ensure the list deletion is visible before we clear
10790 * the owner, closes a race against perf_release() where
10791 * we need to serialize on the owner->perf_event_mutex.
10793 smp_store_release(&event->owner, NULL);
10795 mutex_unlock(&child->perf_event_mutex);
10797 for_each_task_context_nr(ctxn)
10798 perf_event_exit_task_context(child, ctxn);
10801 * The perf_event_exit_task_context calls perf_event_task
10802 * with child's task_ctx, which generates EXIT events for
10803 * child contexts and sets child->perf_event_ctxp[] to NULL.
10804 * At this point we need to send EXIT events to cpu contexts.
10806 perf_event_task(child, NULL, 0);
10809 static void perf_free_event(struct perf_event *event,
10810 struct perf_event_context *ctx)
10812 struct perf_event *parent = event->parent;
10814 if (WARN_ON_ONCE(!parent))
10817 mutex_lock(&parent->child_mutex);
10818 list_del_init(&event->child_list);
10819 mutex_unlock(&parent->child_mutex);
10823 raw_spin_lock_irq(&ctx->lock);
10824 perf_group_detach(event);
10825 list_del_event(event, ctx);
10826 raw_spin_unlock_irq(&ctx->lock);
10831 * Free an unexposed, unused context as created by inheritance by
10832 * perf_event_init_task below, used by fork() in case of fail.
10834 * Not all locks are strictly required, but take them anyway to be nice and
10835 * help out with the lockdep assertions.
10837 void perf_event_free_task(struct task_struct *task)
10839 struct perf_event_context *ctx;
10840 struct perf_event *event, *tmp;
10843 for_each_task_context_nr(ctxn) {
10844 ctx = task->perf_event_ctxp[ctxn];
10848 mutex_lock(&ctx->mutex);
10849 raw_spin_lock_irq(&ctx->lock);
10851 * Destroy the task <-> ctx relation and mark the context dead.
10853 * This is important because even though the task hasn't been
10854 * exposed yet the context has been (through child_list).
10856 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10857 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10858 put_task_struct(task); /* cannot be last */
10859 raw_spin_unlock_irq(&ctx->lock);
10861 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10862 perf_free_event(event, ctx);
10864 mutex_unlock(&ctx->mutex);
10869 void perf_event_delayed_put(struct task_struct *task)
10873 for_each_task_context_nr(ctxn)
10874 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10877 struct file *perf_event_get(unsigned int fd)
10881 file = fget_raw(fd);
10883 return ERR_PTR(-EBADF);
10885 if (file->f_op != &perf_fops) {
10887 return ERR_PTR(-EBADF);
10893 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10896 return ERR_PTR(-EINVAL);
10898 return &event->attr;
10902 * Inherit a event from parent task to child task.
10905 * - valid pointer on success
10906 * - NULL for orphaned events
10907 * - IS_ERR() on error
10909 static struct perf_event *
10910 inherit_event(struct perf_event *parent_event,
10911 struct task_struct *parent,
10912 struct perf_event_context *parent_ctx,
10913 struct task_struct *child,
10914 struct perf_event *group_leader,
10915 struct perf_event_context *child_ctx)
10917 enum perf_event_active_state parent_state = parent_event->state;
10918 struct perf_event *child_event;
10919 unsigned long flags;
10922 * Instead of creating recursive hierarchies of events,
10923 * we link inherited events back to the original parent,
10924 * which has a filp for sure, which we use as the reference
10927 if (parent_event->parent)
10928 parent_event = parent_event->parent;
10930 child_event = perf_event_alloc(&parent_event->attr,
10933 group_leader, parent_event,
10935 if (IS_ERR(child_event))
10936 return child_event;
10939 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10940 * must be under the same lock in order to serialize against
10941 * perf_event_release_kernel(), such that either we must observe
10942 * is_orphaned_event() or they will observe us on the child_list.
10944 mutex_lock(&parent_event->child_mutex);
10945 if (is_orphaned_event(parent_event) ||
10946 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10947 mutex_unlock(&parent_event->child_mutex);
10948 free_event(child_event);
10952 get_ctx(child_ctx);
10955 * Make the child state follow the state of the parent event,
10956 * not its attr.disabled bit. We hold the parent's mutex,
10957 * so we won't race with perf_event_{en, dis}able_family.
10959 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10960 child_event->state = PERF_EVENT_STATE_INACTIVE;
10962 child_event->state = PERF_EVENT_STATE_OFF;
10964 if (parent_event->attr.freq) {
10965 u64 sample_period = parent_event->hw.sample_period;
10966 struct hw_perf_event *hwc = &child_event->hw;
10968 hwc->sample_period = sample_period;
10969 hwc->last_period = sample_period;
10971 local64_set(&hwc->period_left, sample_period);
10974 child_event->ctx = child_ctx;
10975 child_event->overflow_handler = parent_event->overflow_handler;
10976 child_event->overflow_handler_context
10977 = parent_event->overflow_handler_context;
10980 * Precalculate sample_data sizes
10982 perf_event__header_size(child_event);
10983 perf_event__id_header_size(child_event);
10986 * Link it up in the child's context:
10988 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10989 add_event_to_ctx(child_event, child_ctx);
10990 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10993 * Link this into the parent event's child list
10995 list_add_tail(&child_event->child_list, &parent_event->child_list);
10996 mutex_unlock(&parent_event->child_mutex);
10998 return child_event;
11002 * Inherits an event group.
11004 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11005 * This matches with perf_event_release_kernel() removing all child events.
11011 static int inherit_group(struct perf_event *parent_event,
11012 struct task_struct *parent,
11013 struct perf_event_context *parent_ctx,
11014 struct task_struct *child,
11015 struct perf_event_context *child_ctx)
11017 struct perf_event *leader;
11018 struct perf_event *sub;
11019 struct perf_event *child_ctr;
11021 leader = inherit_event(parent_event, parent, parent_ctx,
11022 child, NULL, child_ctx);
11023 if (IS_ERR(leader))
11024 return PTR_ERR(leader);
11026 * @leader can be NULL here because of is_orphaned_event(). In this
11027 * case inherit_event() will create individual events, similar to what
11028 * perf_group_detach() would do anyway.
11030 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
11031 child_ctr = inherit_event(sub, parent, parent_ctx,
11032 child, leader, child_ctx);
11033 if (IS_ERR(child_ctr))
11034 return PTR_ERR(child_ctr);
11040 * Creates the child task context and tries to inherit the event-group.
11042 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11043 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11044 * consistent with perf_event_release_kernel() removing all child events.
11051 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11052 struct perf_event_context *parent_ctx,
11053 struct task_struct *child, int ctxn,
11054 int *inherited_all)
11057 struct perf_event_context *child_ctx;
11059 if (!event->attr.inherit) {
11060 *inherited_all = 0;
11064 child_ctx = child->perf_event_ctxp[ctxn];
11067 * This is executed from the parent task context, so
11068 * inherit events that have been marked for cloning.
11069 * First allocate and initialize a context for the
11072 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11076 child->perf_event_ctxp[ctxn] = child_ctx;
11079 ret = inherit_group(event, parent, parent_ctx,
11083 *inherited_all = 0;
11089 * Initialize the perf_event context in task_struct
11091 static int perf_event_init_context(struct task_struct *child, int ctxn)
11093 struct perf_event_context *child_ctx, *parent_ctx;
11094 struct perf_event_context *cloned_ctx;
11095 struct perf_event *event;
11096 struct task_struct *parent = current;
11097 int inherited_all = 1;
11098 unsigned long flags;
11101 if (likely(!parent->perf_event_ctxp[ctxn]))
11105 * If the parent's context is a clone, pin it so it won't get
11106 * swapped under us.
11108 parent_ctx = perf_pin_task_context(parent, ctxn);
11113 * No need to check if parent_ctx != NULL here; since we saw
11114 * it non-NULL earlier, the only reason for it to become NULL
11115 * is if we exit, and since we're currently in the middle of
11116 * a fork we can't be exiting at the same time.
11120 * Lock the parent list. No need to lock the child - not PID
11121 * hashed yet and not running, so nobody can access it.
11123 mutex_lock(&parent_ctx->mutex);
11126 * We dont have to disable NMIs - we are only looking at
11127 * the list, not manipulating it:
11129 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
11130 ret = inherit_task_group(event, parent, parent_ctx,
11131 child, ctxn, &inherited_all);
11137 * We can't hold ctx->lock when iterating the ->flexible_group list due
11138 * to allocations, but we need to prevent rotation because
11139 * rotate_ctx() will change the list from interrupt context.
11141 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11142 parent_ctx->rotate_disable = 1;
11143 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11145 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
11146 ret = inherit_task_group(event, parent, parent_ctx,
11147 child, ctxn, &inherited_all);
11152 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11153 parent_ctx->rotate_disable = 0;
11155 child_ctx = child->perf_event_ctxp[ctxn];
11157 if (child_ctx && inherited_all) {
11159 * Mark the child context as a clone of the parent
11160 * context, or of whatever the parent is a clone of.
11162 * Note that if the parent is a clone, the holding of
11163 * parent_ctx->lock avoids it from being uncloned.
11165 cloned_ctx = parent_ctx->parent_ctx;
11167 child_ctx->parent_ctx = cloned_ctx;
11168 child_ctx->parent_gen = parent_ctx->parent_gen;
11170 child_ctx->parent_ctx = parent_ctx;
11171 child_ctx->parent_gen = parent_ctx->generation;
11173 get_ctx(child_ctx->parent_ctx);
11176 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11178 mutex_unlock(&parent_ctx->mutex);
11180 perf_unpin_context(parent_ctx);
11181 put_ctx(parent_ctx);
11187 * Initialize the perf_event context in task_struct
11189 int perf_event_init_task(struct task_struct *child)
11193 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11194 mutex_init(&child->perf_event_mutex);
11195 INIT_LIST_HEAD(&child->perf_event_list);
11197 for_each_task_context_nr(ctxn) {
11198 ret = perf_event_init_context(child, ctxn);
11200 perf_event_free_task(child);
11208 static void __init perf_event_init_all_cpus(void)
11210 struct swevent_htable *swhash;
11213 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11215 for_each_possible_cpu(cpu) {
11216 swhash = &per_cpu(swevent_htable, cpu);
11217 mutex_init(&swhash->hlist_mutex);
11218 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11220 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11221 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11223 #ifdef CONFIG_CGROUP_PERF
11224 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11226 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11230 void perf_swevent_init_cpu(unsigned int cpu)
11232 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11234 mutex_lock(&swhash->hlist_mutex);
11235 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11236 struct swevent_hlist *hlist;
11238 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11240 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11242 mutex_unlock(&swhash->hlist_mutex);
11245 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11246 static void __perf_event_exit_context(void *__info)
11248 struct perf_event_context *ctx = __info;
11249 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11250 struct perf_event *event;
11252 raw_spin_lock(&ctx->lock);
11253 list_for_each_entry(event, &ctx->event_list, event_entry)
11254 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11255 raw_spin_unlock(&ctx->lock);
11258 static void perf_event_exit_cpu_context(int cpu)
11260 struct perf_cpu_context *cpuctx;
11261 struct perf_event_context *ctx;
11264 mutex_lock(&pmus_lock);
11265 list_for_each_entry(pmu, &pmus, entry) {
11266 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11267 ctx = &cpuctx->ctx;
11269 mutex_lock(&ctx->mutex);
11270 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11271 cpuctx->online = 0;
11272 mutex_unlock(&ctx->mutex);
11274 cpumask_clear_cpu(cpu, perf_online_mask);
11275 mutex_unlock(&pmus_lock);
11279 static void perf_event_exit_cpu_context(int cpu) { }
11283 int perf_event_init_cpu(unsigned int cpu)
11285 struct perf_cpu_context *cpuctx;
11286 struct perf_event_context *ctx;
11289 perf_swevent_init_cpu(cpu);
11291 mutex_lock(&pmus_lock);
11292 cpumask_set_cpu(cpu, perf_online_mask);
11293 list_for_each_entry(pmu, &pmus, entry) {
11294 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11295 ctx = &cpuctx->ctx;
11297 mutex_lock(&ctx->mutex);
11298 cpuctx->online = 1;
11299 mutex_unlock(&ctx->mutex);
11301 mutex_unlock(&pmus_lock);
11306 int perf_event_exit_cpu(unsigned int cpu)
11308 perf_event_exit_cpu_context(cpu);
11313 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11317 for_each_online_cpu(cpu)
11318 perf_event_exit_cpu(cpu);
11324 * Run the perf reboot notifier at the very last possible moment so that
11325 * the generic watchdog code runs as long as possible.
11327 static struct notifier_block perf_reboot_notifier = {
11328 .notifier_call = perf_reboot,
11329 .priority = INT_MIN,
11332 void __init perf_event_init(void)
11336 idr_init(&pmu_idr);
11338 perf_event_init_all_cpus();
11339 init_srcu_struct(&pmus_srcu);
11340 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11341 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11342 perf_pmu_register(&perf_task_clock, NULL, -1);
11343 perf_tp_register();
11344 perf_event_init_cpu(smp_processor_id());
11345 register_reboot_notifier(&perf_reboot_notifier);
11347 ret = init_hw_breakpoint();
11348 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11351 * Build time assertion that we keep the data_head at the intended
11352 * location. IOW, validation we got the __reserved[] size right.
11354 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11358 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11361 struct perf_pmu_events_attr *pmu_attr =
11362 container_of(attr, struct perf_pmu_events_attr, attr);
11364 if (pmu_attr->event_str)
11365 return sprintf(page, "%s\n", pmu_attr->event_str);
11369 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11371 static int __init perf_event_sysfs_init(void)
11376 mutex_lock(&pmus_lock);
11378 ret = bus_register(&pmu_bus);
11382 list_for_each_entry(pmu, &pmus, entry) {
11383 if (!pmu->name || pmu->type < 0)
11386 ret = pmu_dev_alloc(pmu);
11387 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11389 pmu_bus_running = 1;
11393 mutex_unlock(&pmus_lock);
11397 device_initcall(perf_event_sysfs_init);
11399 #ifdef CONFIG_CGROUP_PERF
11400 static struct cgroup_subsys_state *
11401 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11403 struct perf_cgroup *jc;
11405 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11407 return ERR_PTR(-ENOMEM);
11409 jc->info = alloc_percpu(struct perf_cgroup_info);
11412 return ERR_PTR(-ENOMEM);
11418 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11420 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11422 free_percpu(jc->info);
11426 static int __perf_cgroup_move(void *info)
11428 struct task_struct *task = info;
11430 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11435 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11437 struct task_struct *task;
11438 struct cgroup_subsys_state *css;
11440 cgroup_taskset_for_each(task, css, tset)
11441 task_function_call(task, __perf_cgroup_move, task);
11444 struct cgroup_subsys perf_event_cgrp_subsys = {
11445 .css_alloc = perf_cgroup_css_alloc,
11446 .css_free = perf_cgroup_css_free,
11447 .attach = perf_cgroup_attach,
11449 * Implicitly enable on dfl hierarchy so that perf events can
11450 * always be filtered by cgroup2 path as long as perf_event
11451 * controller is not mounted on a legacy hierarchy.
11453 .implicit_on_dfl = true,
11456 #endif /* CONFIG_CGROUP_PERF */