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>
50 #include <asm/irq_regs.h>
52 typedef int (*remote_function_f)(void *);
54 struct remote_function_call {
55 struct task_struct *p;
56 remote_function_f func;
61 static void remote_function(void *data)
63 struct remote_function_call *tfc = data;
64 struct task_struct *p = tfc->p;
68 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
72 tfc->ret = tfc->func(tfc->info);
76 * task_function_call - call a function on the cpu on which a task runs
77 * @p: the task to evaluate
78 * @func: the function to be called
79 * @info: the function call argument
81 * Calls the function @func when the task is currently running. This might
82 * be on the current CPU, which just calls the function directly
84 * returns: @func return value, or
85 * -ESRCH - when the process isn't running
86 * -EAGAIN - when the process moved away
89 task_function_call(struct task_struct *p, remote_function_f func, void *info)
91 struct remote_function_call data = {
95 .ret = -ESRCH, /* No such (running) process */
99 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
105 * cpu_function_call - call a function on the cpu
106 * @func: the function to be called
107 * @info: the function call argument
109 * Calls the function @func on the remote cpu.
111 * returns: @func return value or -ENXIO when the cpu is offline
113 static int cpu_function_call(int cpu, remote_function_f func, void *info)
115 struct remote_function_call data = {
119 .ret = -ENXIO, /* No such CPU */
122 smp_call_function_single(cpu, remote_function, &data, 1);
127 static inline struct perf_cpu_context *
128 __get_cpu_context(struct perf_event_context *ctx)
130 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
133 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
134 struct perf_event_context *ctx)
136 raw_spin_lock(&cpuctx->ctx.lock);
138 raw_spin_lock(&ctx->lock);
141 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
142 struct perf_event_context *ctx)
145 raw_spin_unlock(&ctx->lock);
146 raw_spin_unlock(&cpuctx->ctx.lock);
149 #define TASK_TOMBSTONE ((void *)-1L)
151 static bool is_kernel_event(struct perf_event *event)
153 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
157 * On task ctx scheduling...
159 * When !ctx->nr_events a task context will not be scheduled. This means
160 * we can disable the scheduler hooks (for performance) without leaving
161 * pending task ctx state.
163 * This however results in two special cases:
165 * - removing the last event from a task ctx; this is relatively straight
166 * forward and is done in __perf_remove_from_context.
168 * - adding the first event to a task ctx; this is tricky because we cannot
169 * rely on ctx->is_active and therefore cannot use event_function_call().
170 * See perf_install_in_context().
172 * This is because we need a ctx->lock serialized variable (ctx->is_active)
173 * to reliably determine if a particular task/context is scheduled in. The
174 * task_curr() use in task_function_call() is racy in that a remote context
175 * switch is not a single atomic operation.
177 * As is, the situation is 'safe' because we set rq->curr before we do the
178 * actual context switch. This means that task_curr() will fail early, but
179 * we'll continue spinning on ctx->is_active until we've passed
180 * perf_event_task_sched_out().
182 * Without this ctx->lock serialized variable we could have race where we find
183 * the task (and hence the context) would not be active while in fact they are.
185 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
188 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
189 struct perf_event_context *, void *);
191 struct event_function_struct {
192 struct perf_event *event;
197 static int event_function(void *info)
199 struct event_function_struct *efs = info;
200 struct perf_event *event = efs->event;
201 struct perf_event_context *ctx = event->ctx;
202 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
203 struct perf_event_context *task_ctx = cpuctx->task_ctx;
206 WARN_ON_ONCE(!irqs_disabled());
208 perf_ctx_lock(cpuctx, task_ctx);
210 * Since we do the IPI call without holding ctx->lock things can have
211 * changed, double check we hit the task we set out to hit.
214 if (ctx->task != current) {
220 * We only use event_function_call() on established contexts,
221 * and event_function() is only ever called when active (or
222 * rather, we'll have bailed in task_function_call() or the
223 * above ctx->task != current test), therefore we must have
224 * ctx->is_active here.
226 WARN_ON_ONCE(!ctx->is_active);
228 * And since we have ctx->is_active, cpuctx->task_ctx must
231 WARN_ON_ONCE(task_ctx != ctx);
233 WARN_ON_ONCE(&cpuctx->ctx != ctx);
236 efs->func(event, cpuctx, ctx, efs->data);
238 perf_ctx_unlock(cpuctx, task_ctx);
243 static void event_function_local(struct perf_event *event, event_f func, void *data)
245 struct event_function_struct efs = {
251 int ret = event_function(&efs);
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);
280 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 if (ctx->is_active) {
294 raw_spin_unlock_irq(&ctx->lock);
297 func(event, NULL, ctx, data);
299 raw_spin_unlock_irq(&ctx->lock);
302 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
303 PERF_FLAG_FD_OUTPUT |\
304 PERF_FLAG_PID_CGROUP |\
305 PERF_FLAG_FD_CLOEXEC)
308 * branch priv levels that need permission checks
310 #define PERF_SAMPLE_BRANCH_PERM_PLM \
311 (PERF_SAMPLE_BRANCH_KERNEL |\
312 PERF_SAMPLE_BRANCH_HV)
315 EVENT_FLEXIBLE = 0x1,
317 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
321 * perf_sched_events : >0 events exist
322 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
324 struct static_key_deferred perf_sched_events __read_mostly;
325 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
326 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
328 static atomic_t nr_mmap_events __read_mostly;
329 static atomic_t nr_comm_events __read_mostly;
330 static atomic_t nr_task_events __read_mostly;
331 static atomic_t nr_freq_events __read_mostly;
332 static atomic_t nr_switch_events __read_mostly;
334 static LIST_HEAD(pmus);
335 static DEFINE_MUTEX(pmus_lock);
336 static struct srcu_struct pmus_srcu;
339 * perf event paranoia level:
340 * -1 - not paranoid at all
341 * 0 - disallow raw tracepoint access for unpriv
342 * 1 - disallow cpu events for unpriv
343 * 2 - disallow kernel profiling for unpriv
345 int sysctl_perf_event_paranoid __read_mostly = 1;
347 /* Minimum for 512 kiB + 1 user control page */
348 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
351 * max perf event sample rate
353 #define DEFAULT_MAX_SAMPLE_RATE 100000
354 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
355 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
357 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
359 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
360 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
362 static int perf_sample_allowed_ns __read_mostly =
363 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
365 static void update_perf_cpu_limits(void)
367 u64 tmp = perf_sample_period_ns;
369 tmp *= sysctl_perf_cpu_time_max_percent;
371 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
374 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
376 int perf_proc_update_handler(struct ctl_table *table, int write,
377 void __user *buffer, size_t *lenp,
380 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
385 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
386 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
387 update_perf_cpu_limits();
392 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
394 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
395 void __user *buffer, size_t *lenp,
398 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
403 update_perf_cpu_limits();
409 * perf samples are done in some very critical code paths (NMIs).
410 * If they take too much CPU time, the system can lock up and not
411 * get any real work done. This will drop the sample rate when
412 * we detect that events are taking too long.
414 #define NR_ACCUMULATED_SAMPLES 128
415 static DEFINE_PER_CPU(u64, running_sample_length);
417 static void perf_duration_warn(struct irq_work *w)
419 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
420 u64 avg_local_sample_len;
421 u64 local_samples_len;
423 local_samples_len = __this_cpu_read(running_sample_length);
424 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
426 printk_ratelimited(KERN_WARNING
427 "perf interrupt took too long (%lld > %lld), lowering "
428 "kernel.perf_event_max_sample_rate to %d\n",
429 avg_local_sample_len, allowed_ns >> 1,
430 sysctl_perf_event_sample_rate);
433 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
435 void perf_sample_event_took(u64 sample_len_ns)
437 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
438 u64 avg_local_sample_len;
439 u64 local_samples_len;
444 /* decay the counter by 1 average sample */
445 local_samples_len = __this_cpu_read(running_sample_length);
446 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
447 local_samples_len += sample_len_ns;
448 __this_cpu_write(running_sample_length, local_samples_len);
451 * note: this will be biased artifically low until we have
452 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
453 * from having to maintain a count.
455 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
457 if (avg_local_sample_len <= allowed_ns)
460 if (max_samples_per_tick <= 1)
463 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
464 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
465 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
467 update_perf_cpu_limits();
469 if (!irq_work_queue(&perf_duration_work)) {
470 early_printk("perf interrupt took too long (%lld > %lld), lowering "
471 "kernel.perf_event_max_sample_rate to %d\n",
472 avg_local_sample_len, allowed_ns >> 1,
473 sysctl_perf_event_sample_rate);
477 static atomic64_t perf_event_id;
479 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
480 enum event_type_t event_type);
482 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
483 enum event_type_t event_type,
484 struct task_struct *task);
486 static void update_context_time(struct perf_event_context *ctx);
487 static u64 perf_event_time(struct perf_event *event);
489 void __weak perf_event_print_debug(void) { }
491 extern __weak const char *perf_pmu_name(void)
496 static inline u64 perf_clock(void)
498 return local_clock();
501 static inline u64 perf_event_clock(struct perf_event *event)
503 return event->clock();
506 #ifdef CONFIG_CGROUP_PERF
509 perf_cgroup_match(struct perf_event *event)
511 struct perf_event_context *ctx = event->ctx;
512 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
514 /* @event doesn't care about cgroup */
518 /* wants specific cgroup scope but @cpuctx isn't associated with any */
523 * Cgroup scoping is recursive. An event enabled for a cgroup is
524 * also enabled for all its descendant cgroups. If @cpuctx's
525 * cgroup is a descendant of @event's (the test covers identity
526 * case), it's a match.
528 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
529 event->cgrp->css.cgroup);
532 static inline void perf_detach_cgroup(struct perf_event *event)
534 css_put(&event->cgrp->css);
538 static inline int is_cgroup_event(struct perf_event *event)
540 return event->cgrp != NULL;
543 static inline u64 perf_cgroup_event_time(struct perf_event *event)
545 struct perf_cgroup_info *t;
547 t = per_cpu_ptr(event->cgrp->info, event->cpu);
551 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
553 struct perf_cgroup_info *info;
558 info = this_cpu_ptr(cgrp->info);
560 info->time += now - info->timestamp;
561 info->timestamp = now;
564 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
566 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
568 __update_cgrp_time(cgrp_out);
571 static inline void update_cgrp_time_from_event(struct perf_event *event)
573 struct perf_cgroup *cgrp;
576 * ensure we access cgroup data only when needed and
577 * when we know the cgroup is pinned (css_get)
579 if (!is_cgroup_event(event))
582 cgrp = perf_cgroup_from_task(current, event->ctx);
584 * Do not update time when cgroup is not active
586 if (cgrp == event->cgrp)
587 __update_cgrp_time(event->cgrp);
591 perf_cgroup_set_timestamp(struct task_struct *task,
592 struct perf_event_context *ctx)
594 struct perf_cgroup *cgrp;
595 struct perf_cgroup_info *info;
598 * ctx->lock held by caller
599 * ensure we do not access cgroup data
600 * unless we have the cgroup pinned (css_get)
602 if (!task || !ctx->nr_cgroups)
605 cgrp = perf_cgroup_from_task(task, ctx);
606 info = this_cpu_ptr(cgrp->info);
607 info->timestamp = ctx->timestamp;
610 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
611 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
614 * reschedule events based on the cgroup constraint of task.
616 * mode SWOUT : schedule out everything
617 * mode SWIN : schedule in based on cgroup for next
619 static void perf_cgroup_switch(struct task_struct *task, int mode)
621 struct perf_cpu_context *cpuctx;
626 * disable interrupts to avoid geting nr_cgroup
627 * changes via __perf_event_disable(). Also
630 local_irq_save(flags);
633 * we reschedule only in the presence of cgroup
634 * constrained events.
637 list_for_each_entry_rcu(pmu, &pmus, entry) {
638 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
639 if (cpuctx->unique_pmu != pmu)
640 continue; /* ensure we process each cpuctx once */
643 * perf_cgroup_events says at least one
644 * context on this CPU has cgroup events.
646 * ctx->nr_cgroups reports the number of cgroup
647 * events for a context.
649 if (cpuctx->ctx.nr_cgroups > 0) {
650 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
651 perf_pmu_disable(cpuctx->ctx.pmu);
653 if (mode & PERF_CGROUP_SWOUT) {
654 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
656 * must not be done before ctxswout due
657 * to event_filter_match() in event_sched_out()
662 if (mode & PERF_CGROUP_SWIN) {
663 WARN_ON_ONCE(cpuctx->cgrp);
665 * set cgrp before ctxsw in to allow
666 * event_filter_match() to not have to pass
668 * we pass the cpuctx->ctx to perf_cgroup_from_task()
669 * because cgorup events are only per-cpu
671 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
672 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
674 perf_pmu_enable(cpuctx->ctx.pmu);
675 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
679 local_irq_restore(flags);
682 static inline void perf_cgroup_sched_out(struct task_struct *task,
683 struct task_struct *next)
685 struct perf_cgroup *cgrp1;
686 struct perf_cgroup *cgrp2 = NULL;
690 * we come here when we know perf_cgroup_events > 0
691 * we do not need to pass the ctx here because we know
692 * we are holding the rcu lock
694 cgrp1 = perf_cgroup_from_task(task, NULL);
695 cgrp2 = perf_cgroup_from_task(next, NULL);
698 * only schedule out current cgroup events if we know
699 * that we are switching to a different cgroup. Otherwise,
700 * do no touch the cgroup events.
703 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
708 static inline void perf_cgroup_sched_in(struct task_struct *prev,
709 struct task_struct *task)
711 struct perf_cgroup *cgrp1;
712 struct perf_cgroup *cgrp2 = NULL;
716 * we come here when we know perf_cgroup_events > 0
717 * we do not need to pass the ctx here because we know
718 * we are holding the rcu lock
720 cgrp1 = perf_cgroup_from_task(task, NULL);
721 cgrp2 = perf_cgroup_from_task(prev, NULL);
724 * only need to schedule in cgroup events if we are changing
725 * cgroup during ctxsw. Cgroup events were not scheduled
726 * out of ctxsw out if that was not the case.
729 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
734 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
735 struct perf_event_attr *attr,
736 struct perf_event *group_leader)
738 struct perf_cgroup *cgrp;
739 struct cgroup_subsys_state *css;
740 struct fd f = fdget(fd);
746 css = css_tryget_online_from_dir(f.file->f_path.dentry,
747 &perf_event_cgrp_subsys);
753 cgrp = container_of(css, struct perf_cgroup, css);
757 * all events in a group must monitor
758 * the same cgroup because a task belongs
759 * to only one perf cgroup at a time
761 if (group_leader && group_leader->cgrp != cgrp) {
762 perf_detach_cgroup(event);
771 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
773 struct perf_cgroup_info *t;
774 t = per_cpu_ptr(event->cgrp->info, event->cpu);
775 event->shadow_ctx_time = now - t->timestamp;
779 perf_cgroup_defer_enabled(struct perf_event *event)
782 * when the current task's perf cgroup does not match
783 * the event's, we need to remember to call the
784 * perf_mark_enable() function the first time a task with
785 * a matching perf cgroup is scheduled in.
787 if (is_cgroup_event(event) && !perf_cgroup_match(event))
788 event->cgrp_defer_enabled = 1;
792 perf_cgroup_mark_enabled(struct perf_event *event,
793 struct perf_event_context *ctx)
795 struct perf_event *sub;
796 u64 tstamp = perf_event_time(event);
798 if (!event->cgrp_defer_enabled)
801 event->cgrp_defer_enabled = 0;
803 event->tstamp_enabled = tstamp - event->total_time_enabled;
804 list_for_each_entry(sub, &event->sibling_list, group_entry) {
805 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
806 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
807 sub->cgrp_defer_enabled = 0;
811 #else /* !CONFIG_CGROUP_PERF */
814 perf_cgroup_match(struct perf_event *event)
819 static inline void perf_detach_cgroup(struct perf_event *event)
822 static inline int is_cgroup_event(struct perf_event *event)
827 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
832 static inline void update_cgrp_time_from_event(struct perf_event *event)
836 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
840 static inline void perf_cgroup_sched_out(struct task_struct *task,
841 struct task_struct *next)
845 static inline void perf_cgroup_sched_in(struct task_struct *prev,
846 struct task_struct *task)
850 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
851 struct perf_event_attr *attr,
852 struct perf_event *group_leader)
858 perf_cgroup_set_timestamp(struct task_struct *task,
859 struct perf_event_context *ctx)
864 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
869 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
873 static inline u64 perf_cgroup_event_time(struct perf_event *event)
879 perf_cgroup_defer_enabled(struct perf_event *event)
884 perf_cgroup_mark_enabled(struct perf_event *event,
885 struct perf_event_context *ctx)
891 * set default to be dependent on timer tick just
894 #define PERF_CPU_HRTIMER (1000 / HZ)
896 * function must be called with interrupts disbled
898 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
900 struct perf_cpu_context *cpuctx;
903 WARN_ON(!irqs_disabled());
905 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
906 rotations = perf_rotate_context(cpuctx);
908 raw_spin_lock(&cpuctx->hrtimer_lock);
910 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
912 cpuctx->hrtimer_active = 0;
913 raw_spin_unlock(&cpuctx->hrtimer_lock);
915 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
918 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
920 struct hrtimer *timer = &cpuctx->hrtimer;
921 struct pmu *pmu = cpuctx->ctx.pmu;
924 /* no multiplexing needed for SW PMU */
925 if (pmu->task_ctx_nr == perf_sw_context)
929 * check default is sane, if not set then force to
930 * default interval (1/tick)
932 interval = pmu->hrtimer_interval_ms;
934 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
936 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
938 raw_spin_lock_init(&cpuctx->hrtimer_lock);
939 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
940 timer->function = perf_mux_hrtimer_handler;
943 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
945 struct hrtimer *timer = &cpuctx->hrtimer;
946 struct pmu *pmu = cpuctx->ctx.pmu;
950 if (pmu->task_ctx_nr == perf_sw_context)
953 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
954 if (!cpuctx->hrtimer_active) {
955 cpuctx->hrtimer_active = 1;
956 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
957 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
959 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
964 void perf_pmu_disable(struct pmu *pmu)
966 int *count = this_cpu_ptr(pmu->pmu_disable_count);
968 pmu->pmu_disable(pmu);
971 void perf_pmu_enable(struct pmu *pmu)
973 int *count = this_cpu_ptr(pmu->pmu_disable_count);
975 pmu->pmu_enable(pmu);
978 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
981 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
982 * perf_event_task_tick() are fully serialized because they're strictly cpu
983 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
984 * disabled, while perf_event_task_tick is called from IRQ context.
986 static void perf_event_ctx_activate(struct perf_event_context *ctx)
988 struct list_head *head = this_cpu_ptr(&active_ctx_list);
990 WARN_ON(!irqs_disabled());
992 WARN_ON(!list_empty(&ctx->active_ctx_list));
994 list_add(&ctx->active_ctx_list, head);
997 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
999 WARN_ON(!irqs_disabled());
1001 WARN_ON(list_empty(&ctx->active_ctx_list));
1003 list_del_init(&ctx->active_ctx_list);
1006 static void get_ctx(struct perf_event_context *ctx)
1008 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1011 static void free_ctx(struct rcu_head *head)
1013 struct perf_event_context *ctx;
1015 ctx = container_of(head, struct perf_event_context, rcu_head);
1016 kfree(ctx->task_ctx_data);
1020 static void put_ctx(struct perf_event_context *ctx)
1022 if (atomic_dec_and_test(&ctx->refcount)) {
1023 if (ctx->parent_ctx)
1024 put_ctx(ctx->parent_ctx);
1025 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1026 put_task_struct(ctx->task);
1027 call_rcu(&ctx->rcu_head, free_ctx);
1032 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1033 * perf_pmu_migrate_context() we need some magic.
1035 * Those places that change perf_event::ctx will hold both
1036 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1038 * Lock ordering is by mutex address. There are two other sites where
1039 * perf_event_context::mutex nests and those are:
1041 * - perf_event_exit_task_context() [ child , 0 ]
1042 * perf_event_exit_event()
1043 * put_event() [ parent, 1 ]
1045 * - perf_event_init_context() [ parent, 0 ]
1046 * inherit_task_group()
1049 * perf_event_alloc()
1051 * perf_try_init_event() [ child , 1 ]
1053 * While it appears there is an obvious deadlock here -- the parent and child
1054 * nesting levels are inverted between the two. This is in fact safe because
1055 * life-time rules separate them. That is an exiting task cannot fork, and a
1056 * spawning task cannot (yet) exit.
1058 * But remember that that these are parent<->child context relations, and
1059 * migration does not affect children, therefore these two orderings should not
1062 * The change in perf_event::ctx does not affect children (as claimed above)
1063 * because the sys_perf_event_open() case will install a new event and break
1064 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1065 * concerned with cpuctx and that doesn't have children.
1067 * The places that change perf_event::ctx will issue:
1069 * perf_remove_from_context();
1070 * synchronize_rcu();
1071 * perf_install_in_context();
1073 * to affect the change. The remove_from_context() + synchronize_rcu() should
1074 * quiesce the event, after which we can install it in the new location. This
1075 * means that only external vectors (perf_fops, prctl) can perturb the event
1076 * while in transit. Therefore all such accessors should also acquire
1077 * perf_event_context::mutex to serialize against this.
1079 * However; because event->ctx can change while we're waiting to acquire
1080 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1084 * task_struct::perf_event_mutex
1085 * perf_event_context::mutex
1086 * perf_event::child_mutex;
1087 * perf_event_context::lock
1088 * perf_event::mmap_mutex
1091 static struct perf_event_context *
1092 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1094 struct perf_event_context *ctx;
1098 ctx = ACCESS_ONCE(event->ctx);
1099 if (!atomic_inc_not_zero(&ctx->refcount)) {
1105 mutex_lock_nested(&ctx->mutex, nesting);
1106 if (event->ctx != ctx) {
1107 mutex_unlock(&ctx->mutex);
1115 static inline struct perf_event_context *
1116 perf_event_ctx_lock(struct perf_event *event)
1118 return perf_event_ctx_lock_nested(event, 0);
1121 static void perf_event_ctx_unlock(struct perf_event *event,
1122 struct perf_event_context *ctx)
1124 mutex_unlock(&ctx->mutex);
1129 * This must be done under the ctx->lock, such as to serialize against
1130 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1131 * calling scheduler related locks and ctx->lock nests inside those.
1133 static __must_check struct perf_event_context *
1134 unclone_ctx(struct perf_event_context *ctx)
1136 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1138 lockdep_assert_held(&ctx->lock);
1141 ctx->parent_ctx = NULL;
1147 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1150 * only top level events have the pid namespace they were created in
1153 event = event->parent;
1155 return task_tgid_nr_ns(p, event->ns);
1158 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1161 * only top level events have the pid namespace they were created in
1164 event = event->parent;
1166 return task_pid_nr_ns(p, event->ns);
1170 * If we inherit events we want to return the parent event id
1173 static u64 primary_event_id(struct perf_event *event)
1178 id = event->parent->id;
1184 * Get the perf_event_context for a task and lock it.
1186 * This has to cope with with the fact that until it is locked,
1187 * the context could get moved to another task.
1189 static struct perf_event_context *
1190 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1192 struct perf_event_context *ctx;
1196 * One of the few rules of preemptible RCU is that one cannot do
1197 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1198 * part of the read side critical section was irqs-enabled -- see
1199 * rcu_read_unlock_special().
1201 * Since ctx->lock nests under rq->lock we must ensure the entire read
1202 * side critical section has interrupts disabled.
1204 local_irq_save(*flags);
1206 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1209 * If this context is a clone of another, it might
1210 * get swapped for another underneath us by
1211 * perf_event_task_sched_out, though the
1212 * rcu_read_lock() protects us from any context
1213 * getting freed. Lock the context and check if it
1214 * got swapped before we could get the lock, and retry
1215 * if so. If we locked the right context, then it
1216 * can't get swapped on us any more.
1218 raw_spin_lock(&ctx->lock);
1219 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1220 raw_spin_unlock(&ctx->lock);
1222 local_irq_restore(*flags);
1226 if (ctx->task == TASK_TOMBSTONE ||
1227 !atomic_inc_not_zero(&ctx->refcount)) {
1228 raw_spin_unlock(&ctx->lock);
1231 WARN_ON_ONCE(ctx->task != task);
1236 local_irq_restore(*flags);
1241 * Get the context for a task and increment its pin_count so it
1242 * can't get swapped to another task. This also increments its
1243 * reference count so that the context can't get freed.
1245 static struct perf_event_context *
1246 perf_pin_task_context(struct task_struct *task, int ctxn)
1248 struct perf_event_context *ctx;
1249 unsigned long flags;
1251 ctx = perf_lock_task_context(task, ctxn, &flags);
1254 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1259 static void perf_unpin_context(struct perf_event_context *ctx)
1261 unsigned long flags;
1263 raw_spin_lock_irqsave(&ctx->lock, flags);
1265 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1269 * Update the record of the current time in a context.
1271 static void update_context_time(struct perf_event_context *ctx)
1273 u64 now = perf_clock();
1275 ctx->time += now - ctx->timestamp;
1276 ctx->timestamp = now;
1279 static u64 perf_event_time(struct perf_event *event)
1281 struct perf_event_context *ctx = event->ctx;
1283 if (is_cgroup_event(event))
1284 return perf_cgroup_event_time(event);
1286 return ctx ? ctx->time : 0;
1290 * Update the total_time_enabled and total_time_running fields for a event.
1291 * The caller of this function needs to hold the ctx->lock.
1293 static void update_event_times(struct perf_event *event)
1295 struct perf_event_context *ctx = event->ctx;
1298 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1299 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1302 * in cgroup mode, time_enabled represents
1303 * the time the event was enabled AND active
1304 * tasks were in the monitored cgroup. This is
1305 * independent of the activity of the context as
1306 * there may be a mix of cgroup and non-cgroup events.
1308 * That is why we treat cgroup events differently
1311 if (is_cgroup_event(event))
1312 run_end = perf_cgroup_event_time(event);
1313 else if (ctx->is_active)
1314 run_end = ctx->time;
1316 run_end = event->tstamp_stopped;
1318 event->total_time_enabled = run_end - event->tstamp_enabled;
1320 if (event->state == PERF_EVENT_STATE_INACTIVE)
1321 run_end = event->tstamp_stopped;
1323 run_end = perf_event_time(event);
1325 event->total_time_running = run_end - event->tstamp_running;
1330 * Update total_time_enabled and total_time_running for all events in a group.
1332 static void update_group_times(struct perf_event *leader)
1334 struct perf_event *event;
1336 update_event_times(leader);
1337 list_for_each_entry(event, &leader->sibling_list, group_entry)
1338 update_event_times(event);
1341 static struct list_head *
1342 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1344 if (event->attr.pinned)
1345 return &ctx->pinned_groups;
1347 return &ctx->flexible_groups;
1351 * Add a event from the lists for its context.
1352 * Must be called with ctx->mutex and ctx->lock held.
1355 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1357 lockdep_assert_held(&ctx->lock);
1359 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1360 event->attach_state |= PERF_ATTACH_CONTEXT;
1363 * If we're a stand alone event or group leader, we go to the context
1364 * list, group events are kept attached to the group so that
1365 * perf_group_detach can, at all times, locate all siblings.
1367 if (event->group_leader == event) {
1368 struct list_head *list;
1370 if (is_software_event(event))
1371 event->group_flags |= PERF_GROUP_SOFTWARE;
1373 list = ctx_group_list(event, ctx);
1374 list_add_tail(&event->group_entry, list);
1377 if (is_cgroup_event(event))
1380 list_add_rcu(&event->event_entry, &ctx->event_list);
1382 if (event->attr.inherit_stat)
1389 * Initialize event state based on the perf_event_attr::disabled.
1391 static inline void perf_event__state_init(struct perf_event *event)
1393 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1394 PERF_EVENT_STATE_INACTIVE;
1397 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1399 int entry = sizeof(u64); /* value */
1403 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1404 size += sizeof(u64);
1406 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1407 size += sizeof(u64);
1409 if (event->attr.read_format & PERF_FORMAT_ID)
1410 entry += sizeof(u64);
1412 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1414 size += sizeof(u64);
1418 event->read_size = size;
1421 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1423 struct perf_sample_data *data;
1426 if (sample_type & PERF_SAMPLE_IP)
1427 size += sizeof(data->ip);
1429 if (sample_type & PERF_SAMPLE_ADDR)
1430 size += sizeof(data->addr);
1432 if (sample_type & PERF_SAMPLE_PERIOD)
1433 size += sizeof(data->period);
1435 if (sample_type & PERF_SAMPLE_WEIGHT)
1436 size += sizeof(data->weight);
1438 if (sample_type & PERF_SAMPLE_READ)
1439 size += event->read_size;
1441 if (sample_type & PERF_SAMPLE_DATA_SRC)
1442 size += sizeof(data->data_src.val);
1444 if (sample_type & PERF_SAMPLE_TRANSACTION)
1445 size += sizeof(data->txn);
1447 event->header_size = size;
1451 * Called at perf_event creation and when events are attached/detached from a
1454 static void perf_event__header_size(struct perf_event *event)
1456 __perf_event_read_size(event,
1457 event->group_leader->nr_siblings);
1458 __perf_event_header_size(event, event->attr.sample_type);
1461 static void perf_event__id_header_size(struct perf_event *event)
1463 struct perf_sample_data *data;
1464 u64 sample_type = event->attr.sample_type;
1467 if (sample_type & PERF_SAMPLE_TID)
1468 size += sizeof(data->tid_entry);
1470 if (sample_type & PERF_SAMPLE_TIME)
1471 size += sizeof(data->time);
1473 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1474 size += sizeof(data->id);
1476 if (sample_type & PERF_SAMPLE_ID)
1477 size += sizeof(data->id);
1479 if (sample_type & PERF_SAMPLE_STREAM_ID)
1480 size += sizeof(data->stream_id);
1482 if (sample_type & PERF_SAMPLE_CPU)
1483 size += sizeof(data->cpu_entry);
1485 event->id_header_size = size;
1488 static bool perf_event_validate_size(struct perf_event *event)
1491 * The values computed here will be over-written when we actually
1494 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1495 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1496 perf_event__id_header_size(event);
1499 * Sum the lot; should not exceed the 64k limit we have on records.
1500 * Conservative limit to allow for callchains and other variable fields.
1502 if (event->read_size + event->header_size +
1503 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1509 static void perf_group_attach(struct perf_event *event)
1511 struct perf_event *group_leader = event->group_leader, *pos;
1514 * We can have double attach due to group movement in perf_event_open.
1516 if (event->attach_state & PERF_ATTACH_GROUP)
1519 event->attach_state |= PERF_ATTACH_GROUP;
1521 if (group_leader == event)
1524 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1526 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1527 !is_software_event(event))
1528 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1530 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1531 group_leader->nr_siblings++;
1533 perf_event__header_size(group_leader);
1535 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1536 perf_event__header_size(pos);
1540 * Remove a event from the lists for its context.
1541 * Must be called with ctx->mutex and ctx->lock held.
1544 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1546 struct perf_cpu_context *cpuctx;
1548 WARN_ON_ONCE(event->ctx != ctx);
1549 lockdep_assert_held(&ctx->lock);
1552 * We can have double detach due to exit/hot-unplug + close.
1554 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1557 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1559 if (is_cgroup_event(event)) {
1562 * Because cgroup events are always per-cpu events, this will
1563 * always be called from the right CPU.
1565 cpuctx = __get_cpu_context(ctx);
1567 * If there are no more cgroup events then clear cgrp to avoid
1568 * stale pointer in update_cgrp_time_from_cpuctx().
1570 if (!ctx->nr_cgroups)
1571 cpuctx->cgrp = NULL;
1575 if (event->attr.inherit_stat)
1578 list_del_rcu(&event->event_entry);
1580 if (event->group_leader == event)
1581 list_del_init(&event->group_entry);
1583 update_group_times(event);
1586 * If event was in error state, then keep it
1587 * that way, otherwise bogus counts will be
1588 * returned on read(). The only way to get out
1589 * of error state is by explicit re-enabling
1592 if (event->state > PERF_EVENT_STATE_OFF)
1593 event->state = PERF_EVENT_STATE_OFF;
1598 static void perf_group_detach(struct perf_event *event)
1600 struct perf_event *sibling, *tmp;
1601 struct list_head *list = NULL;
1604 * We can have double detach due to exit/hot-unplug + close.
1606 if (!(event->attach_state & PERF_ATTACH_GROUP))
1609 event->attach_state &= ~PERF_ATTACH_GROUP;
1612 * If this is a sibling, remove it from its group.
1614 if (event->group_leader != event) {
1615 list_del_init(&event->group_entry);
1616 event->group_leader->nr_siblings--;
1620 if (!list_empty(&event->group_entry))
1621 list = &event->group_entry;
1624 * If this was a group event with sibling events then
1625 * upgrade the siblings to singleton events by adding them
1626 * to whatever list we are on.
1628 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1630 list_move_tail(&sibling->group_entry, list);
1631 sibling->group_leader = sibling;
1633 /* Inherit group flags from the previous leader */
1634 sibling->group_flags = event->group_flags;
1636 WARN_ON_ONCE(sibling->ctx != event->ctx);
1640 perf_event__header_size(event->group_leader);
1642 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1643 perf_event__header_size(tmp);
1646 static bool is_orphaned_event(struct perf_event *event)
1648 return event->state == PERF_EVENT_STATE_DEAD;
1651 static inline int pmu_filter_match(struct perf_event *event)
1653 struct pmu *pmu = event->pmu;
1654 return pmu->filter_match ? pmu->filter_match(event) : 1;
1658 event_filter_match(struct perf_event *event)
1660 return (event->cpu == -1 || event->cpu == smp_processor_id())
1661 && perf_cgroup_match(event) && pmu_filter_match(event);
1665 event_sched_out(struct perf_event *event,
1666 struct perf_cpu_context *cpuctx,
1667 struct perf_event_context *ctx)
1669 u64 tstamp = perf_event_time(event);
1672 WARN_ON_ONCE(event->ctx != ctx);
1673 lockdep_assert_held(&ctx->lock);
1676 * An event which could not be activated because of
1677 * filter mismatch still needs to have its timings
1678 * maintained, otherwise bogus information is return
1679 * via read() for time_enabled, time_running:
1681 if (event->state == PERF_EVENT_STATE_INACTIVE
1682 && !event_filter_match(event)) {
1683 delta = tstamp - event->tstamp_stopped;
1684 event->tstamp_running += delta;
1685 event->tstamp_stopped = tstamp;
1688 if (event->state != PERF_EVENT_STATE_ACTIVE)
1691 perf_pmu_disable(event->pmu);
1693 event->state = PERF_EVENT_STATE_INACTIVE;
1694 if (event->pending_disable) {
1695 event->pending_disable = 0;
1696 event->state = PERF_EVENT_STATE_OFF;
1698 event->tstamp_stopped = tstamp;
1699 event->pmu->del(event, 0);
1702 if (!is_software_event(event))
1703 cpuctx->active_oncpu--;
1704 if (!--ctx->nr_active)
1705 perf_event_ctx_deactivate(ctx);
1706 if (event->attr.freq && event->attr.sample_freq)
1708 if (event->attr.exclusive || !cpuctx->active_oncpu)
1709 cpuctx->exclusive = 0;
1711 perf_pmu_enable(event->pmu);
1715 group_sched_out(struct perf_event *group_event,
1716 struct perf_cpu_context *cpuctx,
1717 struct perf_event_context *ctx)
1719 struct perf_event *event;
1720 int state = group_event->state;
1722 event_sched_out(group_event, cpuctx, ctx);
1725 * Schedule out siblings (if any):
1727 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1728 event_sched_out(event, cpuctx, ctx);
1730 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1731 cpuctx->exclusive = 0;
1734 #define DETACH_GROUP 0x01UL
1737 * Cross CPU call to remove a performance event
1739 * We disable the event on the hardware level first. After that we
1740 * remove it from the context list.
1743 __perf_remove_from_context(struct perf_event *event,
1744 struct perf_cpu_context *cpuctx,
1745 struct perf_event_context *ctx,
1748 unsigned long flags = (unsigned long)info;
1750 event_sched_out(event, cpuctx, ctx);
1751 if (flags & DETACH_GROUP)
1752 perf_group_detach(event);
1753 list_del_event(event, ctx);
1755 if (!ctx->nr_events && ctx->is_active) {
1758 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1759 cpuctx->task_ctx = NULL;
1765 * Remove the event from a task's (or a CPU's) list of events.
1767 * If event->ctx is a cloned context, callers must make sure that
1768 * every task struct that event->ctx->task could possibly point to
1769 * remains valid. This is OK when called from perf_release since
1770 * that only calls us on the top-level context, which can't be a clone.
1771 * When called from perf_event_exit_task, it's OK because the
1772 * context has been detached from its task.
1774 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1776 lockdep_assert_held(&event->ctx->mutex);
1778 event_function_call(event, __perf_remove_from_context, (void *)flags);
1782 * Cross CPU call to disable a performance event
1784 static void __perf_event_disable(struct perf_event *event,
1785 struct perf_cpu_context *cpuctx,
1786 struct perf_event_context *ctx,
1789 if (event->state < PERF_EVENT_STATE_INACTIVE)
1792 update_context_time(ctx);
1793 update_cgrp_time_from_event(event);
1794 update_group_times(event);
1795 if (event == event->group_leader)
1796 group_sched_out(event, cpuctx, ctx);
1798 event_sched_out(event, cpuctx, ctx);
1799 event->state = PERF_EVENT_STATE_OFF;
1805 * If event->ctx is a cloned context, callers must make sure that
1806 * every task struct that event->ctx->task could possibly point to
1807 * remains valid. This condition is satisifed when called through
1808 * perf_event_for_each_child or perf_event_for_each because they
1809 * hold the top-level event's child_mutex, so any descendant that
1810 * goes to exit will block in perf_event_exit_event().
1812 * When called from perf_pending_event it's OK because event->ctx
1813 * is the current context on this CPU and preemption is disabled,
1814 * hence we can't get into perf_event_task_sched_out for this context.
1816 static void _perf_event_disable(struct perf_event *event)
1818 struct perf_event_context *ctx = event->ctx;
1820 raw_spin_lock_irq(&ctx->lock);
1821 if (event->state <= PERF_EVENT_STATE_OFF) {
1822 raw_spin_unlock_irq(&ctx->lock);
1825 raw_spin_unlock_irq(&ctx->lock);
1827 event_function_call(event, __perf_event_disable, NULL);
1830 void perf_event_disable_local(struct perf_event *event)
1832 event_function_local(event, __perf_event_disable, NULL);
1836 * Strictly speaking kernel users cannot create groups and therefore this
1837 * interface does not need the perf_event_ctx_lock() magic.
1839 void perf_event_disable(struct perf_event *event)
1841 struct perf_event_context *ctx;
1843 ctx = perf_event_ctx_lock(event);
1844 _perf_event_disable(event);
1845 perf_event_ctx_unlock(event, ctx);
1847 EXPORT_SYMBOL_GPL(perf_event_disable);
1849 static void perf_set_shadow_time(struct perf_event *event,
1850 struct perf_event_context *ctx,
1854 * use the correct time source for the time snapshot
1856 * We could get by without this by leveraging the
1857 * fact that to get to this function, the caller
1858 * has most likely already called update_context_time()
1859 * and update_cgrp_time_xx() and thus both timestamp
1860 * are identical (or very close). Given that tstamp is,
1861 * already adjusted for cgroup, we could say that:
1862 * tstamp - ctx->timestamp
1864 * tstamp - cgrp->timestamp.
1866 * Then, in perf_output_read(), the calculation would
1867 * work with no changes because:
1868 * - event is guaranteed scheduled in
1869 * - no scheduled out in between
1870 * - thus the timestamp would be the same
1872 * But this is a bit hairy.
1874 * So instead, we have an explicit cgroup call to remain
1875 * within the time time source all along. We believe it
1876 * is cleaner and simpler to understand.
1878 if (is_cgroup_event(event))
1879 perf_cgroup_set_shadow_time(event, tstamp);
1881 event->shadow_ctx_time = tstamp - ctx->timestamp;
1884 #define MAX_INTERRUPTS (~0ULL)
1886 static void perf_log_throttle(struct perf_event *event, int enable);
1887 static void perf_log_itrace_start(struct perf_event *event);
1890 event_sched_in(struct perf_event *event,
1891 struct perf_cpu_context *cpuctx,
1892 struct perf_event_context *ctx)
1894 u64 tstamp = perf_event_time(event);
1897 lockdep_assert_held(&ctx->lock);
1899 if (event->state <= PERF_EVENT_STATE_OFF)
1902 event->state = PERF_EVENT_STATE_ACTIVE;
1903 event->oncpu = smp_processor_id();
1906 * Unthrottle events, since we scheduled we might have missed several
1907 * ticks already, also for a heavily scheduling task there is little
1908 * guarantee it'll get a tick in a timely manner.
1910 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1911 perf_log_throttle(event, 1);
1912 event->hw.interrupts = 0;
1916 * The new state must be visible before we turn it on in the hardware:
1920 perf_pmu_disable(event->pmu);
1922 perf_set_shadow_time(event, ctx, tstamp);
1924 perf_log_itrace_start(event);
1926 if (event->pmu->add(event, PERF_EF_START)) {
1927 event->state = PERF_EVENT_STATE_INACTIVE;
1933 event->tstamp_running += tstamp - event->tstamp_stopped;
1935 if (!is_software_event(event))
1936 cpuctx->active_oncpu++;
1937 if (!ctx->nr_active++)
1938 perf_event_ctx_activate(ctx);
1939 if (event->attr.freq && event->attr.sample_freq)
1942 if (event->attr.exclusive)
1943 cpuctx->exclusive = 1;
1946 perf_pmu_enable(event->pmu);
1952 group_sched_in(struct perf_event *group_event,
1953 struct perf_cpu_context *cpuctx,
1954 struct perf_event_context *ctx)
1956 struct perf_event *event, *partial_group = NULL;
1957 struct pmu *pmu = ctx->pmu;
1958 u64 now = ctx->time;
1959 bool simulate = false;
1961 if (group_event->state == PERF_EVENT_STATE_OFF)
1964 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1966 if (event_sched_in(group_event, cpuctx, ctx)) {
1967 pmu->cancel_txn(pmu);
1968 perf_mux_hrtimer_restart(cpuctx);
1973 * Schedule in siblings as one group (if any):
1975 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1976 if (event_sched_in(event, cpuctx, ctx)) {
1977 partial_group = event;
1982 if (!pmu->commit_txn(pmu))
1987 * Groups can be scheduled in as one unit only, so undo any
1988 * partial group before returning:
1989 * The events up to the failed event are scheduled out normally,
1990 * tstamp_stopped will be updated.
1992 * The failed events and the remaining siblings need to have
1993 * their timings updated as if they had gone thru event_sched_in()
1994 * and event_sched_out(). This is required to get consistent timings
1995 * across the group. This also takes care of the case where the group
1996 * could never be scheduled by ensuring tstamp_stopped is set to mark
1997 * the time the event was actually stopped, such that time delta
1998 * calculation in update_event_times() is correct.
2000 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2001 if (event == partial_group)
2005 event->tstamp_running += now - event->tstamp_stopped;
2006 event->tstamp_stopped = now;
2008 event_sched_out(event, cpuctx, ctx);
2011 event_sched_out(group_event, cpuctx, ctx);
2013 pmu->cancel_txn(pmu);
2015 perf_mux_hrtimer_restart(cpuctx);
2021 * Work out whether we can put this event group on the CPU now.
2023 static int group_can_go_on(struct perf_event *event,
2024 struct perf_cpu_context *cpuctx,
2028 * Groups consisting entirely of software events can always go on.
2030 if (event->group_flags & PERF_GROUP_SOFTWARE)
2033 * If an exclusive group is already on, no other hardware
2036 if (cpuctx->exclusive)
2039 * If this group is exclusive and there are already
2040 * events on the CPU, it can't go on.
2042 if (event->attr.exclusive && cpuctx->active_oncpu)
2045 * Otherwise, try to add it if all previous groups were able
2051 static void add_event_to_ctx(struct perf_event *event,
2052 struct perf_event_context *ctx)
2054 u64 tstamp = perf_event_time(event);
2056 list_add_event(event, ctx);
2057 perf_group_attach(event);
2058 event->tstamp_enabled = tstamp;
2059 event->tstamp_running = tstamp;
2060 event->tstamp_stopped = tstamp;
2063 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2064 struct perf_event_context *ctx);
2066 ctx_sched_in(struct perf_event_context *ctx,
2067 struct perf_cpu_context *cpuctx,
2068 enum event_type_t event_type,
2069 struct task_struct *task);
2071 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2072 struct perf_event_context *ctx,
2073 struct task_struct *task)
2075 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2077 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2078 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2080 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2083 static void ctx_resched(struct perf_cpu_context *cpuctx,
2084 struct perf_event_context *task_ctx)
2086 perf_pmu_disable(cpuctx->ctx.pmu);
2088 task_ctx_sched_out(cpuctx, task_ctx);
2089 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2090 perf_event_sched_in(cpuctx, task_ctx, current);
2091 perf_pmu_enable(cpuctx->ctx.pmu);
2095 * Cross CPU call to install and enable a performance event
2097 * Must be called with ctx->mutex held
2099 static int __perf_install_in_context(void *info)
2101 struct perf_event_context *ctx = info;
2102 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2103 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2105 raw_spin_lock(&cpuctx->ctx.lock);
2107 raw_spin_lock(&ctx->lock);
2109 * If we hit the 'wrong' task, we've since scheduled and
2110 * everything should be sorted, nothing to do!
2113 if (ctx->task != current)
2117 * If task_ctx is set, it had better be to us.
2119 WARN_ON_ONCE(cpuctx->task_ctx != ctx && cpuctx->task_ctx);
2120 } else if (task_ctx) {
2121 raw_spin_lock(&task_ctx->lock);
2124 ctx_resched(cpuctx, task_ctx);
2126 perf_ctx_unlock(cpuctx, task_ctx);
2132 * Attach a performance event to a context
2135 perf_install_in_context(struct perf_event_context *ctx,
2136 struct perf_event *event,
2139 struct task_struct *task = NULL;
2141 lockdep_assert_held(&ctx->mutex);
2144 if (event->cpu != -1)
2148 * Installing events is tricky because we cannot rely on ctx->is_active
2149 * to be set in case this is the nr_events 0 -> 1 transition.
2151 * So what we do is we add the event to the list here, which will allow
2152 * a future context switch to DTRT and then send a racy IPI. If the IPI
2153 * fails to hit the right task, this means a context switch must have
2154 * happened and that will have taken care of business.
2156 raw_spin_lock_irq(&ctx->lock);
2160 * If between ctx = find_get_context() and mutex_lock(&ctx->mutex) the
2161 * ctx gets destroyed, we must not install an event into it.
2163 * This is normally tested for after we acquire the mutex, so this is
2166 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2167 raw_spin_unlock_irq(&ctx->lock);
2171 if (ctx->is_active) {
2172 update_context_time(ctx);
2173 update_cgrp_time_from_event(event);
2176 add_event_to_ctx(event, ctx);
2177 raw_spin_unlock_irq(&ctx->lock);
2180 task_function_call(task, __perf_install_in_context, ctx);
2182 cpu_function_call(cpu, __perf_install_in_context, ctx);
2186 * Put a event into inactive state and update time fields.
2187 * Enabling the leader of a group effectively enables all
2188 * the group members that aren't explicitly disabled, so we
2189 * have to update their ->tstamp_enabled also.
2190 * Note: this works for group members as well as group leaders
2191 * since the non-leader members' sibling_lists will be empty.
2193 static void __perf_event_mark_enabled(struct perf_event *event)
2195 struct perf_event *sub;
2196 u64 tstamp = perf_event_time(event);
2198 event->state = PERF_EVENT_STATE_INACTIVE;
2199 event->tstamp_enabled = tstamp - event->total_time_enabled;
2200 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2201 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2202 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2207 * Cross CPU call to enable a performance event
2209 static void __perf_event_enable(struct perf_event *event,
2210 struct perf_cpu_context *cpuctx,
2211 struct perf_event_context *ctx,
2214 struct perf_event *leader = event->group_leader;
2215 struct perf_event_context *task_ctx;
2217 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2218 event->state <= PERF_EVENT_STATE_ERROR)
2221 update_context_time(ctx);
2222 __perf_event_mark_enabled(event);
2224 if (!ctx->is_active)
2227 if (!event_filter_match(event)) {
2228 if (is_cgroup_event(event)) {
2229 perf_cgroup_set_timestamp(current, ctx); // XXX ?
2230 perf_cgroup_defer_enabled(event);
2236 * If the event is in a group and isn't the group leader,
2237 * then don't put it on unless the group is on.
2239 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2242 task_ctx = cpuctx->task_ctx;
2244 WARN_ON_ONCE(task_ctx != ctx);
2246 ctx_resched(cpuctx, task_ctx);
2252 * If event->ctx is a cloned context, callers must make sure that
2253 * every task struct that event->ctx->task could possibly point to
2254 * remains valid. This condition is satisfied when called through
2255 * perf_event_for_each_child or perf_event_for_each as described
2256 * for perf_event_disable.
2258 static void _perf_event_enable(struct perf_event *event)
2260 struct perf_event_context *ctx = event->ctx;
2262 raw_spin_lock_irq(&ctx->lock);
2263 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2264 event->state < PERF_EVENT_STATE_ERROR) {
2265 raw_spin_unlock_irq(&ctx->lock);
2270 * If the event is in error state, clear that first.
2272 * That way, if we see the event in error state below, we know that it
2273 * has gone back into error state, as distinct from the task having
2274 * been scheduled away before the cross-call arrived.
2276 if (event->state == PERF_EVENT_STATE_ERROR)
2277 event->state = PERF_EVENT_STATE_OFF;
2278 raw_spin_unlock_irq(&ctx->lock);
2280 event_function_call(event, __perf_event_enable, NULL);
2284 * See perf_event_disable();
2286 void perf_event_enable(struct perf_event *event)
2288 struct perf_event_context *ctx;
2290 ctx = perf_event_ctx_lock(event);
2291 _perf_event_enable(event);
2292 perf_event_ctx_unlock(event, ctx);
2294 EXPORT_SYMBOL_GPL(perf_event_enable);
2296 static int _perf_event_refresh(struct perf_event *event, int refresh)
2299 * not supported on inherited events
2301 if (event->attr.inherit || !is_sampling_event(event))
2304 atomic_add(refresh, &event->event_limit);
2305 _perf_event_enable(event);
2311 * See perf_event_disable()
2313 int perf_event_refresh(struct perf_event *event, int refresh)
2315 struct perf_event_context *ctx;
2318 ctx = perf_event_ctx_lock(event);
2319 ret = _perf_event_refresh(event, refresh);
2320 perf_event_ctx_unlock(event, ctx);
2324 EXPORT_SYMBOL_GPL(perf_event_refresh);
2326 static void ctx_sched_out(struct perf_event_context *ctx,
2327 struct perf_cpu_context *cpuctx,
2328 enum event_type_t event_type)
2330 int is_active = ctx->is_active;
2331 struct perf_event *event;
2333 lockdep_assert_held(&ctx->lock);
2335 if (likely(!ctx->nr_events)) {
2337 * See __perf_remove_from_context().
2339 WARN_ON_ONCE(ctx->is_active);
2341 WARN_ON_ONCE(cpuctx->task_ctx);
2345 ctx->is_active &= ~event_type;
2347 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2348 if (!ctx->is_active)
2349 cpuctx->task_ctx = NULL;
2352 update_context_time(ctx);
2353 update_cgrp_time_from_cpuctx(cpuctx);
2354 if (!ctx->nr_active)
2357 perf_pmu_disable(ctx->pmu);
2358 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2359 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2360 group_sched_out(event, cpuctx, ctx);
2363 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2364 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2365 group_sched_out(event, cpuctx, ctx);
2367 perf_pmu_enable(ctx->pmu);
2371 * Test whether two contexts are equivalent, i.e. whether they have both been
2372 * cloned from the same version of the same context.
2374 * Equivalence is measured using a generation number in the context that is
2375 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2376 * and list_del_event().
2378 static int context_equiv(struct perf_event_context *ctx1,
2379 struct perf_event_context *ctx2)
2381 lockdep_assert_held(&ctx1->lock);
2382 lockdep_assert_held(&ctx2->lock);
2384 /* Pinning disables the swap optimization */
2385 if (ctx1->pin_count || ctx2->pin_count)
2388 /* If ctx1 is the parent of ctx2 */
2389 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2392 /* If ctx2 is the parent of ctx1 */
2393 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2397 * If ctx1 and ctx2 have the same parent; we flatten the parent
2398 * hierarchy, see perf_event_init_context().
2400 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2401 ctx1->parent_gen == ctx2->parent_gen)
2408 static void __perf_event_sync_stat(struct perf_event *event,
2409 struct perf_event *next_event)
2413 if (!event->attr.inherit_stat)
2417 * Update the event value, we cannot use perf_event_read()
2418 * because we're in the middle of a context switch and have IRQs
2419 * disabled, which upsets smp_call_function_single(), however
2420 * we know the event must be on the current CPU, therefore we
2421 * don't need to use it.
2423 switch (event->state) {
2424 case PERF_EVENT_STATE_ACTIVE:
2425 event->pmu->read(event);
2428 case PERF_EVENT_STATE_INACTIVE:
2429 update_event_times(event);
2437 * In order to keep per-task stats reliable we need to flip the event
2438 * values when we flip the contexts.
2440 value = local64_read(&next_event->count);
2441 value = local64_xchg(&event->count, value);
2442 local64_set(&next_event->count, value);
2444 swap(event->total_time_enabled, next_event->total_time_enabled);
2445 swap(event->total_time_running, next_event->total_time_running);
2448 * Since we swizzled the values, update the user visible data too.
2450 perf_event_update_userpage(event);
2451 perf_event_update_userpage(next_event);
2454 static void perf_event_sync_stat(struct perf_event_context *ctx,
2455 struct perf_event_context *next_ctx)
2457 struct perf_event *event, *next_event;
2462 update_context_time(ctx);
2464 event = list_first_entry(&ctx->event_list,
2465 struct perf_event, event_entry);
2467 next_event = list_first_entry(&next_ctx->event_list,
2468 struct perf_event, event_entry);
2470 while (&event->event_entry != &ctx->event_list &&
2471 &next_event->event_entry != &next_ctx->event_list) {
2473 __perf_event_sync_stat(event, next_event);
2475 event = list_next_entry(event, event_entry);
2476 next_event = list_next_entry(next_event, event_entry);
2480 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2481 struct task_struct *next)
2483 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2484 struct perf_event_context *next_ctx;
2485 struct perf_event_context *parent, *next_parent;
2486 struct perf_cpu_context *cpuctx;
2492 cpuctx = __get_cpu_context(ctx);
2493 if (!cpuctx->task_ctx)
2497 next_ctx = next->perf_event_ctxp[ctxn];
2501 parent = rcu_dereference(ctx->parent_ctx);
2502 next_parent = rcu_dereference(next_ctx->parent_ctx);
2504 /* If neither context have a parent context; they cannot be clones. */
2505 if (!parent && !next_parent)
2508 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2510 * Looks like the two contexts are clones, so we might be
2511 * able to optimize the context switch. We lock both
2512 * contexts and check that they are clones under the
2513 * lock (including re-checking that neither has been
2514 * uncloned in the meantime). It doesn't matter which
2515 * order we take the locks because no other cpu could
2516 * be trying to lock both of these tasks.
2518 raw_spin_lock(&ctx->lock);
2519 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2520 if (context_equiv(ctx, next_ctx)) {
2521 WRITE_ONCE(ctx->task, next);
2522 WRITE_ONCE(next_ctx->task, task);
2524 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2527 * RCU_INIT_POINTER here is safe because we've not
2528 * modified the ctx and the above modification of
2529 * ctx->task and ctx->task_ctx_data are immaterial
2530 * since those values are always verified under
2531 * ctx->lock which we're now holding.
2533 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2534 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2538 perf_event_sync_stat(ctx, next_ctx);
2540 raw_spin_unlock(&next_ctx->lock);
2541 raw_spin_unlock(&ctx->lock);
2547 raw_spin_lock(&ctx->lock);
2548 task_ctx_sched_out(cpuctx, ctx);
2549 raw_spin_unlock(&ctx->lock);
2553 void perf_sched_cb_dec(struct pmu *pmu)
2555 this_cpu_dec(perf_sched_cb_usages);
2558 void perf_sched_cb_inc(struct pmu *pmu)
2560 this_cpu_inc(perf_sched_cb_usages);
2564 * This function provides the context switch callback to the lower code
2565 * layer. It is invoked ONLY when the context switch callback is enabled.
2567 static void perf_pmu_sched_task(struct task_struct *prev,
2568 struct task_struct *next,
2571 struct perf_cpu_context *cpuctx;
2573 unsigned long flags;
2578 local_irq_save(flags);
2582 list_for_each_entry_rcu(pmu, &pmus, entry) {
2583 if (pmu->sched_task) {
2584 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2586 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2588 perf_pmu_disable(pmu);
2590 pmu->sched_task(cpuctx->task_ctx, sched_in);
2592 perf_pmu_enable(pmu);
2594 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2600 local_irq_restore(flags);
2603 static void perf_event_switch(struct task_struct *task,
2604 struct task_struct *next_prev, bool sched_in);
2606 #define for_each_task_context_nr(ctxn) \
2607 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2610 * Called from scheduler to remove the events of the current task,
2611 * with interrupts disabled.
2613 * We stop each event and update the event value in event->count.
2615 * This does not protect us against NMI, but disable()
2616 * sets the disabled bit in the control field of event _before_
2617 * accessing the event control register. If a NMI hits, then it will
2618 * not restart the event.
2620 void __perf_event_task_sched_out(struct task_struct *task,
2621 struct task_struct *next)
2625 if (__this_cpu_read(perf_sched_cb_usages))
2626 perf_pmu_sched_task(task, next, false);
2628 if (atomic_read(&nr_switch_events))
2629 perf_event_switch(task, next, false);
2631 for_each_task_context_nr(ctxn)
2632 perf_event_context_sched_out(task, ctxn, next);
2635 * if cgroup events exist on this CPU, then we need
2636 * to check if we have to switch out PMU state.
2637 * cgroup event are system-wide mode only
2639 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2640 perf_cgroup_sched_out(task, next);
2643 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2644 struct perf_event_context *ctx)
2646 if (!cpuctx->task_ctx)
2649 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2652 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2656 * Called with IRQs disabled
2658 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2659 enum event_type_t event_type)
2661 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2665 ctx_pinned_sched_in(struct perf_event_context *ctx,
2666 struct perf_cpu_context *cpuctx)
2668 struct perf_event *event;
2670 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2671 if (event->state <= PERF_EVENT_STATE_OFF)
2673 if (!event_filter_match(event))
2676 /* may need to reset tstamp_enabled */
2677 if (is_cgroup_event(event))
2678 perf_cgroup_mark_enabled(event, ctx);
2680 if (group_can_go_on(event, cpuctx, 1))
2681 group_sched_in(event, cpuctx, ctx);
2684 * If this pinned group hasn't been scheduled,
2685 * put it in error state.
2687 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2688 update_group_times(event);
2689 event->state = PERF_EVENT_STATE_ERROR;
2695 ctx_flexible_sched_in(struct perf_event_context *ctx,
2696 struct perf_cpu_context *cpuctx)
2698 struct perf_event *event;
2701 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2702 /* Ignore events in OFF or ERROR state */
2703 if (event->state <= PERF_EVENT_STATE_OFF)
2706 * Listen to the 'cpu' scheduling filter constraint
2709 if (!event_filter_match(event))
2712 /* may need to reset tstamp_enabled */
2713 if (is_cgroup_event(event))
2714 perf_cgroup_mark_enabled(event, ctx);
2716 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2717 if (group_sched_in(event, cpuctx, ctx))
2724 ctx_sched_in(struct perf_event_context *ctx,
2725 struct perf_cpu_context *cpuctx,
2726 enum event_type_t event_type,
2727 struct task_struct *task)
2729 int is_active = ctx->is_active;
2732 lockdep_assert_held(&ctx->lock);
2734 if (likely(!ctx->nr_events))
2737 ctx->is_active |= event_type;
2740 cpuctx->task_ctx = ctx;
2742 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2746 ctx->timestamp = now;
2747 perf_cgroup_set_timestamp(task, ctx);
2749 * First go through the list and put on any pinned groups
2750 * in order to give them the best chance of going on.
2752 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2753 ctx_pinned_sched_in(ctx, cpuctx);
2755 /* Then walk through the lower prio flexible groups */
2756 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2757 ctx_flexible_sched_in(ctx, cpuctx);
2760 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2761 enum event_type_t event_type,
2762 struct task_struct *task)
2764 struct perf_event_context *ctx = &cpuctx->ctx;
2766 ctx_sched_in(ctx, cpuctx, event_type, task);
2769 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2770 struct task_struct *task)
2772 struct perf_cpu_context *cpuctx;
2774 cpuctx = __get_cpu_context(ctx);
2775 if (cpuctx->task_ctx == ctx)
2778 perf_ctx_lock(cpuctx, ctx);
2779 perf_pmu_disable(ctx->pmu);
2781 * We want to keep the following priority order:
2782 * cpu pinned (that don't need to move), task pinned,
2783 * cpu flexible, task flexible.
2785 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2786 perf_event_sched_in(cpuctx, ctx, task);
2787 perf_pmu_enable(ctx->pmu);
2788 perf_ctx_unlock(cpuctx, ctx);
2792 * Called from scheduler to add the events of the current task
2793 * with interrupts disabled.
2795 * We restore the event value and then enable it.
2797 * This does not protect us against NMI, but enable()
2798 * sets the enabled bit in the control field of event _before_
2799 * accessing the event control register. If a NMI hits, then it will
2800 * keep the event running.
2802 void __perf_event_task_sched_in(struct task_struct *prev,
2803 struct task_struct *task)
2805 struct perf_event_context *ctx;
2809 * If cgroup events exist on this CPU, then we need to check if we have
2810 * to switch in PMU state; cgroup event are system-wide mode only.
2812 * Since cgroup events are CPU events, we must schedule these in before
2813 * we schedule in the task events.
2815 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2816 perf_cgroup_sched_in(prev, task);
2818 for_each_task_context_nr(ctxn) {
2819 ctx = task->perf_event_ctxp[ctxn];
2823 perf_event_context_sched_in(ctx, task);
2826 if (atomic_read(&nr_switch_events))
2827 perf_event_switch(task, prev, true);
2829 if (__this_cpu_read(perf_sched_cb_usages))
2830 perf_pmu_sched_task(prev, task, true);
2833 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2835 u64 frequency = event->attr.sample_freq;
2836 u64 sec = NSEC_PER_SEC;
2837 u64 divisor, dividend;
2839 int count_fls, nsec_fls, frequency_fls, sec_fls;
2841 count_fls = fls64(count);
2842 nsec_fls = fls64(nsec);
2843 frequency_fls = fls64(frequency);
2847 * We got @count in @nsec, with a target of sample_freq HZ
2848 * the target period becomes:
2851 * period = -------------------
2852 * @nsec * sample_freq
2857 * Reduce accuracy by one bit such that @a and @b converge
2858 * to a similar magnitude.
2860 #define REDUCE_FLS(a, b) \
2862 if (a##_fls > b##_fls) { \
2872 * Reduce accuracy until either term fits in a u64, then proceed with
2873 * the other, so that finally we can do a u64/u64 division.
2875 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2876 REDUCE_FLS(nsec, frequency);
2877 REDUCE_FLS(sec, count);
2880 if (count_fls + sec_fls > 64) {
2881 divisor = nsec * frequency;
2883 while (count_fls + sec_fls > 64) {
2884 REDUCE_FLS(count, sec);
2888 dividend = count * sec;
2890 dividend = count * sec;
2892 while (nsec_fls + frequency_fls > 64) {
2893 REDUCE_FLS(nsec, frequency);
2897 divisor = nsec * frequency;
2903 return div64_u64(dividend, divisor);
2906 static DEFINE_PER_CPU(int, perf_throttled_count);
2907 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2909 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2911 struct hw_perf_event *hwc = &event->hw;
2912 s64 period, sample_period;
2915 period = perf_calculate_period(event, nsec, count);
2917 delta = (s64)(period - hwc->sample_period);
2918 delta = (delta + 7) / 8; /* low pass filter */
2920 sample_period = hwc->sample_period + delta;
2925 hwc->sample_period = sample_period;
2927 if (local64_read(&hwc->period_left) > 8*sample_period) {
2929 event->pmu->stop(event, PERF_EF_UPDATE);
2931 local64_set(&hwc->period_left, 0);
2934 event->pmu->start(event, PERF_EF_RELOAD);
2939 * combine freq adjustment with unthrottling to avoid two passes over the
2940 * events. At the same time, make sure, having freq events does not change
2941 * the rate of unthrottling as that would introduce bias.
2943 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2946 struct perf_event *event;
2947 struct hw_perf_event *hwc;
2948 u64 now, period = TICK_NSEC;
2952 * only need to iterate over all events iff:
2953 * - context have events in frequency mode (needs freq adjust)
2954 * - there are events to unthrottle on this cpu
2956 if (!(ctx->nr_freq || needs_unthr))
2959 raw_spin_lock(&ctx->lock);
2960 perf_pmu_disable(ctx->pmu);
2962 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2963 if (event->state != PERF_EVENT_STATE_ACTIVE)
2966 if (!event_filter_match(event))
2969 perf_pmu_disable(event->pmu);
2973 if (hwc->interrupts == MAX_INTERRUPTS) {
2974 hwc->interrupts = 0;
2975 perf_log_throttle(event, 1);
2976 event->pmu->start(event, 0);
2979 if (!event->attr.freq || !event->attr.sample_freq)
2983 * stop the event and update event->count
2985 event->pmu->stop(event, PERF_EF_UPDATE);
2987 now = local64_read(&event->count);
2988 delta = now - hwc->freq_count_stamp;
2989 hwc->freq_count_stamp = now;
2993 * reload only if value has changed
2994 * we have stopped the event so tell that
2995 * to perf_adjust_period() to avoid stopping it
2999 perf_adjust_period(event, period, delta, false);
3001 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3003 perf_pmu_enable(event->pmu);
3006 perf_pmu_enable(ctx->pmu);
3007 raw_spin_unlock(&ctx->lock);
3011 * Round-robin a context's events:
3013 static void rotate_ctx(struct perf_event_context *ctx)
3016 * Rotate the first entry last of non-pinned groups. Rotation might be
3017 * disabled by the inheritance code.
3019 if (!ctx->rotate_disable)
3020 list_rotate_left(&ctx->flexible_groups);
3023 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3025 struct perf_event_context *ctx = NULL;
3028 if (cpuctx->ctx.nr_events) {
3029 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3033 ctx = cpuctx->task_ctx;
3034 if (ctx && ctx->nr_events) {
3035 if (ctx->nr_events != ctx->nr_active)
3042 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3043 perf_pmu_disable(cpuctx->ctx.pmu);
3045 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3047 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3049 rotate_ctx(&cpuctx->ctx);
3053 perf_event_sched_in(cpuctx, ctx, current);
3055 perf_pmu_enable(cpuctx->ctx.pmu);
3056 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3062 #ifdef CONFIG_NO_HZ_FULL
3063 bool perf_event_can_stop_tick(void)
3065 if (atomic_read(&nr_freq_events) ||
3066 __this_cpu_read(perf_throttled_count))
3073 void perf_event_task_tick(void)
3075 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3076 struct perf_event_context *ctx, *tmp;
3079 WARN_ON(!irqs_disabled());
3081 __this_cpu_inc(perf_throttled_seq);
3082 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3084 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3085 perf_adjust_freq_unthr_context(ctx, throttled);
3088 static int event_enable_on_exec(struct perf_event *event,
3089 struct perf_event_context *ctx)
3091 if (!event->attr.enable_on_exec)
3094 event->attr.enable_on_exec = 0;
3095 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3098 __perf_event_mark_enabled(event);
3104 * Enable all of a task's events that have been marked enable-on-exec.
3105 * This expects task == current.
3107 static void perf_event_enable_on_exec(int ctxn)
3109 struct perf_event_context *ctx, *clone_ctx = NULL;
3110 struct perf_cpu_context *cpuctx;
3111 struct perf_event *event;
3112 unsigned long flags;
3115 local_irq_save(flags);
3116 ctx = current->perf_event_ctxp[ctxn];
3117 if (!ctx || !ctx->nr_events)
3120 cpuctx = __get_cpu_context(ctx);
3121 perf_ctx_lock(cpuctx, ctx);
3122 list_for_each_entry(event, &ctx->event_list, event_entry)
3123 enabled |= event_enable_on_exec(event, ctx);
3126 * Unclone and reschedule this context if we enabled any event.
3129 clone_ctx = unclone_ctx(ctx);
3130 ctx_resched(cpuctx, ctx);
3132 perf_ctx_unlock(cpuctx, ctx);
3135 local_irq_restore(flags);
3141 void perf_event_exec(void)
3146 for_each_task_context_nr(ctxn)
3147 perf_event_enable_on_exec(ctxn);
3151 struct perf_read_data {
3152 struct perf_event *event;
3158 * Cross CPU call to read the hardware event
3160 static void __perf_event_read(void *info)
3162 struct perf_read_data *data = info;
3163 struct perf_event *sub, *event = data->event;
3164 struct perf_event_context *ctx = event->ctx;
3165 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3166 struct pmu *pmu = event->pmu;
3169 * If this is a task context, we need to check whether it is
3170 * the current task context of this cpu. If not it has been
3171 * scheduled out before the smp call arrived. In that case
3172 * event->count would have been updated to a recent sample
3173 * when the event was scheduled out.
3175 if (ctx->task && cpuctx->task_ctx != ctx)
3178 raw_spin_lock(&ctx->lock);
3179 if (ctx->is_active) {
3180 update_context_time(ctx);
3181 update_cgrp_time_from_event(event);
3184 update_event_times(event);
3185 if (event->state != PERF_EVENT_STATE_ACTIVE)
3194 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3198 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3199 update_event_times(sub);
3200 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3202 * Use sibling's PMU rather than @event's since
3203 * sibling could be on different (eg: software) PMU.
3205 sub->pmu->read(sub);
3209 data->ret = pmu->commit_txn(pmu);
3212 raw_spin_unlock(&ctx->lock);
3215 static inline u64 perf_event_count(struct perf_event *event)
3217 if (event->pmu->count)
3218 return event->pmu->count(event);
3220 return __perf_event_count(event);
3224 * NMI-safe method to read a local event, that is an event that
3226 * - either for the current task, or for this CPU
3227 * - does not have inherit set, for inherited task events
3228 * will not be local and we cannot read them atomically
3229 * - must not have a pmu::count method
3231 u64 perf_event_read_local(struct perf_event *event)
3233 unsigned long flags;
3237 * Disabling interrupts avoids all counter scheduling (context
3238 * switches, timer based rotation and IPIs).
3240 local_irq_save(flags);
3242 /* If this is a per-task event, it must be for current */
3243 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3244 event->hw.target != current);
3246 /* If this is a per-CPU event, it must be for this CPU */
3247 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3248 event->cpu != smp_processor_id());
3251 * It must not be an event with inherit set, we cannot read
3252 * all child counters from atomic context.
3254 WARN_ON_ONCE(event->attr.inherit);
3257 * It must not have a pmu::count method, those are not
3260 WARN_ON_ONCE(event->pmu->count);
3263 * If the event is currently on this CPU, its either a per-task event,
3264 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3267 if (event->oncpu == smp_processor_id())
3268 event->pmu->read(event);
3270 val = local64_read(&event->count);
3271 local_irq_restore(flags);
3276 static int perf_event_read(struct perf_event *event, bool group)
3281 * If event is enabled and currently active on a CPU, update the
3282 * value in the event structure:
3284 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3285 struct perf_read_data data = {
3290 smp_call_function_single(event->oncpu,
3291 __perf_event_read, &data, 1);
3293 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3294 struct perf_event_context *ctx = event->ctx;
3295 unsigned long flags;
3297 raw_spin_lock_irqsave(&ctx->lock, flags);
3299 * may read while context is not active
3300 * (e.g., thread is blocked), in that case
3301 * we cannot update context time
3303 if (ctx->is_active) {
3304 update_context_time(ctx);
3305 update_cgrp_time_from_event(event);
3308 update_group_times(event);
3310 update_event_times(event);
3311 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3318 * Initialize the perf_event context in a task_struct:
3320 static void __perf_event_init_context(struct perf_event_context *ctx)
3322 raw_spin_lock_init(&ctx->lock);
3323 mutex_init(&ctx->mutex);
3324 INIT_LIST_HEAD(&ctx->active_ctx_list);
3325 INIT_LIST_HEAD(&ctx->pinned_groups);
3326 INIT_LIST_HEAD(&ctx->flexible_groups);
3327 INIT_LIST_HEAD(&ctx->event_list);
3328 atomic_set(&ctx->refcount, 1);
3331 static struct perf_event_context *
3332 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3334 struct perf_event_context *ctx;
3336 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3340 __perf_event_init_context(ctx);
3343 get_task_struct(task);
3350 static struct task_struct *
3351 find_lively_task_by_vpid(pid_t vpid)
3353 struct task_struct *task;
3360 task = find_task_by_vpid(vpid);
3362 get_task_struct(task);
3366 return ERR_PTR(-ESRCH);
3368 /* Reuse ptrace permission checks for now. */
3370 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
3375 put_task_struct(task);
3376 return ERR_PTR(err);
3381 * Returns a matching context with refcount and pincount.
3383 static struct perf_event_context *
3384 find_get_context(struct pmu *pmu, struct task_struct *task,
3385 struct perf_event *event)
3387 struct perf_event_context *ctx, *clone_ctx = NULL;
3388 struct perf_cpu_context *cpuctx;
3389 void *task_ctx_data = NULL;
3390 unsigned long flags;
3392 int cpu = event->cpu;
3395 /* Must be root to operate on a CPU event: */
3396 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3397 return ERR_PTR(-EACCES);
3400 * We could be clever and allow to attach a event to an
3401 * offline CPU and activate it when the CPU comes up, but
3404 if (!cpu_online(cpu))
3405 return ERR_PTR(-ENODEV);
3407 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3416 ctxn = pmu->task_ctx_nr;
3420 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3421 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3422 if (!task_ctx_data) {
3429 ctx = perf_lock_task_context(task, ctxn, &flags);
3431 clone_ctx = unclone_ctx(ctx);
3434 if (task_ctx_data && !ctx->task_ctx_data) {
3435 ctx->task_ctx_data = task_ctx_data;
3436 task_ctx_data = NULL;
3438 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3443 ctx = alloc_perf_context(pmu, task);
3448 if (task_ctx_data) {
3449 ctx->task_ctx_data = task_ctx_data;
3450 task_ctx_data = NULL;
3454 mutex_lock(&task->perf_event_mutex);
3456 * If it has already passed perf_event_exit_task().
3457 * we must see PF_EXITING, it takes this mutex too.
3459 if (task->flags & PF_EXITING)
3461 else if (task->perf_event_ctxp[ctxn])
3466 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3468 mutex_unlock(&task->perf_event_mutex);
3470 if (unlikely(err)) {
3479 kfree(task_ctx_data);
3483 kfree(task_ctx_data);
3484 return ERR_PTR(err);
3487 static void perf_event_free_filter(struct perf_event *event);
3488 static void perf_event_free_bpf_prog(struct perf_event *event);
3490 static void free_event_rcu(struct rcu_head *head)
3492 struct perf_event *event;
3494 event = container_of(head, struct perf_event, rcu_head);
3496 put_pid_ns(event->ns);
3497 perf_event_free_filter(event);
3501 static void ring_buffer_attach(struct perf_event *event,
3502 struct ring_buffer *rb);
3504 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3509 if (is_cgroup_event(event))
3510 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3513 static void unaccount_event(struct perf_event *event)
3520 if (event->attach_state & PERF_ATTACH_TASK)
3522 if (event->attr.mmap || event->attr.mmap_data)
3523 atomic_dec(&nr_mmap_events);
3524 if (event->attr.comm)
3525 atomic_dec(&nr_comm_events);
3526 if (event->attr.task)
3527 atomic_dec(&nr_task_events);
3528 if (event->attr.freq)
3529 atomic_dec(&nr_freq_events);
3530 if (event->attr.context_switch) {
3532 atomic_dec(&nr_switch_events);
3534 if (is_cgroup_event(event))
3536 if (has_branch_stack(event))
3540 static_key_slow_dec_deferred(&perf_sched_events);
3542 unaccount_event_cpu(event, event->cpu);
3546 * The following implement mutual exclusion of events on "exclusive" pmus
3547 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3548 * at a time, so we disallow creating events that might conflict, namely:
3550 * 1) cpu-wide events in the presence of per-task events,
3551 * 2) per-task events in the presence of cpu-wide events,
3552 * 3) two matching events on the same context.
3554 * The former two cases are handled in the allocation path (perf_event_alloc(),
3555 * _free_event()), the latter -- before the first perf_install_in_context().
3557 static int exclusive_event_init(struct perf_event *event)
3559 struct pmu *pmu = event->pmu;
3561 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3565 * Prevent co-existence of per-task and cpu-wide events on the
3566 * same exclusive pmu.
3568 * Negative pmu::exclusive_cnt means there are cpu-wide
3569 * events on this "exclusive" pmu, positive means there are
3572 * Since this is called in perf_event_alloc() path, event::ctx
3573 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3574 * to mean "per-task event", because unlike other attach states it
3575 * never gets cleared.
3577 if (event->attach_state & PERF_ATTACH_TASK) {
3578 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3581 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3588 static void exclusive_event_destroy(struct perf_event *event)
3590 struct pmu *pmu = event->pmu;
3592 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3595 /* see comment in exclusive_event_init() */
3596 if (event->attach_state & PERF_ATTACH_TASK)
3597 atomic_dec(&pmu->exclusive_cnt);
3599 atomic_inc(&pmu->exclusive_cnt);
3602 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3604 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3605 (e1->cpu == e2->cpu ||
3612 /* Called under the same ctx::mutex as perf_install_in_context() */
3613 static bool exclusive_event_installable(struct perf_event *event,
3614 struct perf_event_context *ctx)
3616 struct perf_event *iter_event;
3617 struct pmu *pmu = event->pmu;
3619 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3622 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3623 if (exclusive_event_match(iter_event, event))
3630 static void _free_event(struct perf_event *event)
3632 irq_work_sync(&event->pending);
3634 unaccount_event(event);
3638 * Can happen when we close an event with re-directed output.
3640 * Since we have a 0 refcount, perf_mmap_close() will skip
3641 * over us; possibly making our ring_buffer_put() the last.
3643 mutex_lock(&event->mmap_mutex);
3644 ring_buffer_attach(event, NULL);
3645 mutex_unlock(&event->mmap_mutex);
3648 if (is_cgroup_event(event))
3649 perf_detach_cgroup(event);
3651 if (!event->parent) {
3652 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3653 put_callchain_buffers();
3656 perf_event_free_bpf_prog(event);
3659 event->destroy(event);
3662 put_ctx(event->ctx);
3665 exclusive_event_destroy(event);
3666 module_put(event->pmu->module);
3669 call_rcu(&event->rcu_head, free_event_rcu);
3673 * Used to free events which have a known refcount of 1, such as in error paths
3674 * where the event isn't exposed yet and inherited events.
3676 static void free_event(struct perf_event *event)
3678 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3679 "unexpected event refcount: %ld; ptr=%p\n",
3680 atomic_long_read(&event->refcount), event)) {
3681 /* leak to avoid use-after-free */
3689 * Remove user event from the owner task.
3691 static void perf_remove_from_owner(struct perf_event *event)
3693 struct task_struct *owner;
3697 * Matches the smp_store_release() in perf_event_exit_task(). If we
3698 * observe !owner it means the list deletion is complete and we can
3699 * indeed free this event, otherwise we need to serialize on
3700 * owner->perf_event_mutex.
3702 owner = lockless_dereference(event->owner);
3705 * Since delayed_put_task_struct() also drops the last
3706 * task reference we can safely take a new reference
3707 * while holding the rcu_read_lock().
3709 get_task_struct(owner);
3715 * If we're here through perf_event_exit_task() we're already
3716 * holding ctx->mutex which would be an inversion wrt. the
3717 * normal lock order.
3719 * However we can safely take this lock because its the child
3722 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3725 * We have to re-check the event->owner field, if it is cleared
3726 * we raced with perf_event_exit_task(), acquiring the mutex
3727 * ensured they're done, and we can proceed with freeing the
3731 list_del_init(&event->owner_entry);
3732 smp_store_release(&event->owner, NULL);
3734 mutex_unlock(&owner->perf_event_mutex);
3735 put_task_struct(owner);
3739 static void put_event(struct perf_event *event)
3741 if (!atomic_long_dec_and_test(&event->refcount))
3748 * Kill an event dead; while event:refcount will preserve the event
3749 * object, it will not preserve its functionality. Once the last 'user'
3750 * gives up the object, we'll destroy the thing.
3752 int perf_event_release_kernel(struct perf_event *event)
3754 struct perf_event_context *ctx = event->ctx;
3755 struct perf_event *child, *tmp;
3758 * If we got here through err_file: fput(event_file); we will not have
3759 * attached to a context yet.
3762 WARN_ON_ONCE(event->attach_state &
3763 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
3767 if (!is_kernel_event(event))
3768 perf_remove_from_owner(event);
3770 ctx = perf_event_ctx_lock(event);
3771 WARN_ON_ONCE(ctx->parent_ctx);
3772 perf_remove_from_context(event, DETACH_GROUP);
3774 raw_spin_lock_irq(&ctx->lock);
3776 * Mark this even as STATE_DEAD, there is no external reference to it
3779 * Anybody acquiring event->child_mutex after the below loop _must_
3780 * also see this, most importantly inherit_event() which will avoid
3781 * placing more children on the list.
3783 * Thus this guarantees that we will in fact observe and kill _ALL_
3786 event->state = PERF_EVENT_STATE_DEAD;
3787 raw_spin_unlock_irq(&ctx->lock);
3789 perf_event_ctx_unlock(event, ctx);
3792 mutex_lock(&event->child_mutex);
3793 list_for_each_entry(child, &event->child_list, child_list) {
3796 * Cannot change, child events are not migrated, see the
3797 * comment with perf_event_ctx_lock_nested().
3799 ctx = lockless_dereference(child->ctx);
3801 * Since child_mutex nests inside ctx::mutex, we must jump
3802 * through hoops. We start by grabbing a reference on the ctx.
3804 * Since the event cannot get freed while we hold the
3805 * child_mutex, the context must also exist and have a !0
3811 * Now that we have a ctx ref, we can drop child_mutex, and
3812 * acquire ctx::mutex without fear of it going away. Then we
3813 * can re-acquire child_mutex.
3815 mutex_unlock(&event->child_mutex);
3816 mutex_lock(&ctx->mutex);
3817 mutex_lock(&event->child_mutex);
3820 * Now that we hold ctx::mutex and child_mutex, revalidate our
3821 * state, if child is still the first entry, it didn't get freed
3822 * and we can continue doing so.
3824 tmp = list_first_entry_or_null(&event->child_list,
3825 struct perf_event, child_list);
3827 perf_remove_from_context(child, DETACH_GROUP);
3828 list_del(&child->child_list);
3831 * This matches the refcount bump in inherit_event();
3832 * this can't be the last reference.
3837 mutex_unlock(&event->child_mutex);
3838 mutex_unlock(&ctx->mutex);
3842 mutex_unlock(&event->child_mutex);
3845 put_event(event); /* Must be the 'last' reference */
3848 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3851 * Called when the last reference to the file is gone.
3853 static int perf_release(struct inode *inode, struct file *file)
3855 perf_event_release_kernel(file->private_data);
3859 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3861 struct perf_event *child;
3867 mutex_lock(&event->child_mutex);
3869 (void)perf_event_read(event, false);
3870 total += perf_event_count(event);
3872 *enabled += event->total_time_enabled +
3873 atomic64_read(&event->child_total_time_enabled);
3874 *running += event->total_time_running +
3875 atomic64_read(&event->child_total_time_running);
3877 list_for_each_entry(child, &event->child_list, child_list) {
3878 (void)perf_event_read(child, false);
3879 total += perf_event_count(child);
3880 *enabled += child->total_time_enabled;
3881 *running += child->total_time_running;
3883 mutex_unlock(&event->child_mutex);
3887 EXPORT_SYMBOL_GPL(perf_event_read_value);
3889 static int __perf_read_group_add(struct perf_event *leader,
3890 u64 read_format, u64 *values)
3892 struct perf_event *sub;
3893 int n = 1; /* skip @nr */
3896 ret = perf_event_read(leader, true);
3901 * Since we co-schedule groups, {enabled,running} times of siblings
3902 * will be identical to those of the leader, so we only publish one
3905 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3906 values[n++] += leader->total_time_enabled +
3907 atomic64_read(&leader->child_total_time_enabled);
3910 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3911 values[n++] += leader->total_time_running +
3912 atomic64_read(&leader->child_total_time_running);
3916 * Write {count,id} tuples for every sibling.
3918 values[n++] += perf_event_count(leader);
3919 if (read_format & PERF_FORMAT_ID)
3920 values[n++] = primary_event_id(leader);
3922 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3923 values[n++] += perf_event_count(sub);
3924 if (read_format & PERF_FORMAT_ID)
3925 values[n++] = primary_event_id(sub);
3931 static int perf_read_group(struct perf_event *event,
3932 u64 read_format, char __user *buf)
3934 struct perf_event *leader = event->group_leader, *child;
3935 struct perf_event_context *ctx = leader->ctx;
3939 lockdep_assert_held(&ctx->mutex);
3941 values = kzalloc(event->read_size, GFP_KERNEL);
3945 values[0] = 1 + leader->nr_siblings;
3948 * By locking the child_mutex of the leader we effectively
3949 * lock the child list of all siblings.. XXX explain how.
3951 mutex_lock(&leader->child_mutex);
3953 ret = __perf_read_group_add(leader, read_format, values);
3957 list_for_each_entry(child, &leader->child_list, child_list) {
3958 ret = __perf_read_group_add(child, read_format, values);
3963 mutex_unlock(&leader->child_mutex);
3965 ret = event->read_size;
3966 if (copy_to_user(buf, values, event->read_size))
3971 mutex_unlock(&leader->child_mutex);
3977 static int perf_read_one(struct perf_event *event,
3978 u64 read_format, char __user *buf)
3980 u64 enabled, running;
3984 values[n++] = perf_event_read_value(event, &enabled, &running);
3985 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3986 values[n++] = enabled;
3987 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3988 values[n++] = running;
3989 if (read_format & PERF_FORMAT_ID)
3990 values[n++] = primary_event_id(event);
3992 if (copy_to_user(buf, values, n * sizeof(u64)))
3995 return n * sizeof(u64);
3998 static bool is_event_hup(struct perf_event *event)
4002 if (event->state > PERF_EVENT_STATE_EXIT)
4005 mutex_lock(&event->child_mutex);
4006 no_children = list_empty(&event->child_list);
4007 mutex_unlock(&event->child_mutex);
4012 * Read the performance event - simple non blocking version for now
4015 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4017 u64 read_format = event->attr.read_format;
4021 * Return end-of-file for a read on a event that is in
4022 * error state (i.e. because it was pinned but it couldn't be
4023 * scheduled on to the CPU at some point).
4025 if (event->state == PERF_EVENT_STATE_ERROR)
4028 if (count < event->read_size)
4031 WARN_ON_ONCE(event->ctx->parent_ctx);
4032 if (read_format & PERF_FORMAT_GROUP)
4033 ret = perf_read_group(event, read_format, buf);
4035 ret = perf_read_one(event, read_format, buf);
4041 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4043 struct perf_event *event = file->private_data;
4044 struct perf_event_context *ctx;
4047 ctx = perf_event_ctx_lock(event);
4048 ret = __perf_read(event, buf, count);
4049 perf_event_ctx_unlock(event, ctx);
4054 static unsigned int perf_poll(struct file *file, poll_table *wait)
4056 struct perf_event *event = file->private_data;
4057 struct ring_buffer *rb;
4058 unsigned int events = POLLHUP;
4060 poll_wait(file, &event->waitq, wait);
4062 if (is_event_hup(event))
4066 * Pin the event->rb by taking event->mmap_mutex; otherwise
4067 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4069 mutex_lock(&event->mmap_mutex);
4072 events = atomic_xchg(&rb->poll, 0);
4073 mutex_unlock(&event->mmap_mutex);
4077 static void _perf_event_reset(struct perf_event *event)
4079 (void)perf_event_read(event, false);
4080 local64_set(&event->count, 0);
4081 perf_event_update_userpage(event);
4085 * Holding the top-level event's child_mutex means that any
4086 * descendant process that has inherited this event will block
4087 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4088 * task existence requirements of perf_event_enable/disable.
4090 static void perf_event_for_each_child(struct perf_event *event,
4091 void (*func)(struct perf_event *))
4093 struct perf_event *child;
4095 WARN_ON_ONCE(event->ctx->parent_ctx);
4097 mutex_lock(&event->child_mutex);
4099 list_for_each_entry(child, &event->child_list, child_list)
4101 mutex_unlock(&event->child_mutex);
4104 static void perf_event_for_each(struct perf_event *event,
4105 void (*func)(struct perf_event *))
4107 struct perf_event_context *ctx = event->ctx;
4108 struct perf_event *sibling;
4110 lockdep_assert_held(&ctx->mutex);
4112 event = event->group_leader;
4114 perf_event_for_each_child(event, func);
4115 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4116 perf_event_for_each_child(sibling, func);
4119 static void __perf_event_period(struct perf_event *event,
4120 struct perf_cpu_context *cpuctx,
4121 struct perf_event_context *ctx,
4124 u64 value = *((u64 *)info);
4127 if (event->attr.freq) {
4128 event->attr.sample_freq = value;
4130 event->attr.sample_period = value;
4131 event->hw.sample_period = value;
4134 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4136 perf_pmu_disable(ctx->pmu);
4137 event->pmu->stop(event, PERF_EF_UPDATE);
4140 local64_set(&event->hw.period_left, 0);
4143 event->pmu->start(event, PERF_EF_RELOAD);
4144 perf_pmu_enable(ctx->pmu);
4148 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4152 if (!is_sampling_event(event))
4155 if (copy_from_user(&value, arg, sizeof(value)))
4161 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4164 event_function_call(event, __perf_event_period, &value);
4169 static const struct file_operations perf_fops;
4171 static inline int perf_fget_light(int fd, struct fd *p)
4173 struct fd f = fdget(fd);
4177 if (f.file->f_op != &perf_fops) {
4185 static int perf_event_set_output(struct perf_event *event,
4186 struct perf_event *output_event);
4187 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4188 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4190 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4192 void (*func)(struct perf_event *);
4196 case PERF_EVENT_IOC_ENABLE:
4197 func = _perf_event_enable;
4199 case PERF_EVENT_IOC_DISABLE:
4200 func = _perf_event_disable;
4202 case PERF_EVENT_IOC_RESET:
4203 func = _perf_event_reset;
4206 case PERF_EVENT_IOC_REFRESH:
4207 return _perf_event_refresh(event, arg);
4209 case PERF_EVENT_IOC_PERIOD:
4210 return perf_event_period(event, (u64 __user *)arg);
4212 case PERF_EVENT_IOC_ID:
4214 u64 id = primary_event_id(event);
4216 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4221 case PERF_EVENT_IOC_SET_OUTPUT:
4225 struct perf_event *output_event;
4227 ret = perf_fget_light(arg, &output);
4230 output_event = output.file->private_data;
4231 ret = perf_event_set_output(event, output_event);
4234 ret = perf_event_set_output(event, NULL);
4239 case PERF_EVENT_IOC_SET_FILTER:
4240 return perf_event_set_filter(event, (void __user *)arg);
4242 case PERF_EVENT_IOC_SET_BPF:
4243 return perf_event_set_bpf_prog(event, arg);
4249 if (flags & PERF_IOC_FLAG_GROUP)
4250 perf_event_for_each(event, func);
4252 perf_event_for_each_child(event, func);
4257 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4259 struct perf_event *event = file->private_data;
4260 struct perf_event_context *ctx;
4263 ctx = perf_event_ctx_lock(event);
4264 ret = _perf_ioctl(event, cmd, arg);
4265 perf_event_ctx_unlock(event, ctx);
4270 #ifdef CONFIG_COMPAT
4271 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4274 switch (_IOC_NR(cmd)) {
4275 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4276 case _IOC_NR(PERF_EVENT_IOC_ID):
4277 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4278 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4279 cmd &= ~IOCSIZE_MASK;
4280 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4284 return perf_ioctl(file, cmd, arg);
4287 # define perf_compat_ioctl NULL
4290 int perf_event_task_enable(void)
4292 struct perf_event_context *ctx;
4293 struct perf_event *event;
4295 mutex_lock(¤t->perf_event_mutex);
4296 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4297 ctx = perf_event_ctx_lock(event);
4298 perf_event_for_each_child(event, _perf_event_enable);
4299 perf_event_ctx_unlock(event, ctx);
4301 mutex_unlock(¤t->perf_event_mutex);
4306 int perf_event_task_disable(void)
4308 struct perf_event_context *ctx;
4309 struct perf_event *event;
4311 mutex_lock(¤t->perf_event_mutex);
4312 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4313 ctx = perf_event_ctx_lock(event);
4314 perf_event_for_each_child(event, _perf_event_disable);
4315 perf_event_ctx_unlock(event, ctx);
4317 mutex_unlock(¤t->perf_event_mutex);
4322 static int perf_event_index(struct perf_event *event)
4324 if (event->hw.state & PERF_HES_STOPPED)
4327 if (event->state != PERF_EVENT_STATE_ACTIVE)
4330 return event->pmu->event_idx(event);
4333 static void calc_timer_values(struct perf_event *event,
4340 *now = perf_clock();
4341 ctx_time = event->shadow_ctx_time + *now;
4342 *enabled = ctx_time - event->tstamp_enabled;
4343 *running = ctx_time - event->tstamp_running;
4346 static void perf_event_init_userpage(struct perf_event *event)
4348 struct perf_event_mmap_page *userpg;
4349 struct ring_buffer *rb;
4352 rb = rcu_dereference(event->rb);
4356 userpg = rb->user_page;
4358 /* Allow new userspace to detect that bit 0 is deprecated */
4359 userpg->cap_bit0_is_deprecated = 1;
4360 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4361 userpg->data_offset = PAGE_SIZE;
4362 userpg->data_size = perf_data_size(rb);
4368 void __weak arch_perf_update_userpage(
4369 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4374 * Callers need to ensure there can be no nesting of this function, otherwise
4375 * the seqlock logic goes bad. We can not serialize this because the arch
4376 * code calls this from NMI context.
4378 void perf_event_update_userpage(struct perf_event *event)
4380 struct perf_event_mmap_page *userpg;
4381 struct ring_buffer *rb;
4382 u64 enabled, running, now;
4385 rb = rcu_dereference(event->rb);
4390 * compute total_time_enabled, total_time_running
4391 * based on snapshot values taken when the event
4392 * was last scheduled in.
4394 * we cannot simply called update_context_time()
4395 * because of locking issue as we can be called in
4398 calc_timer_values(event, &now, &enabled, &running);
4400 userpg = rb->user_page;
4402 * Disable preemption so as to not let the corresponding user-space
4403 * spin too long if we get preempted.
4408 userpg->index = perf_event_index(event);
4409 userpg->offset = perf_event_count(event);
4411 userpg->offset -= local64_read(&event->hw.prev_count);
4413 userpg->time_enabled = enabled +
4414 atomic64_read(&event->child_total_time_enabled);
4416 userpg->time_running = running +
4417 atomic64_read(&event->child_total_time_running);
4419 arch_perf_update_userpage(event, userpg, now);
4428 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4430 struct perf_event *event = vma->vm_file->private_data;
4431 struct ring_buffer *rb;
4432 int ret = VM_FAULT_SIGBUS;
4434 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4435 if (vmf->pgoff == 0)
4441 rb = rcu_dereference(event->rb);
4445 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4448 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4452 get_page(vmf->page);
4453 vmf->page->mapping = vma->vm_file->f_mapping;
4454 vmf->page->index = vmf->pgoff;
4463 static void ring_buffer_attach(struct perf_event *event,
4464 struct ring_buffer *rb)
4466 struct ring_buffer *old_rb = NULL;
4467 unsigned long flags;
4471 * Should be impossible, we set this when removing
4472 * event->rb_entry and wait/clear when adding event->rb_entry.
4474 WARN_ON_ONCE(event->rcu_pending);
4477 spin_lock_irqsave(&old_rb->event_lock, flags);
4478 list_del_rcu(&event->rb_entry);
4479 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4481 event->rcu_batches = get_state_synchronize_rcu();
4482 event->rcu_pending = 1;
4486 if (event->rcu_pending) {
4487 cond_synchronize_rcu(event->rcu_batches);
4488 event->rcu_pending = 0;
4491 spin_lock_irqsave(&rb->event_lock, flags);
4492 list_add_rcu(&event->rb_entry, &rb->event_list);
4493 spin_unlock_irqrestore(&rb->event_lock, flags);
4496 rcu_assign_pointer(event->rb, rb);
4499 ring_buffer_put(old_rb);
4501 * Since we detached before setting the new rb, so that we
4502 * could attach the new rb, we could have missed a wakeup.
4505 wake_up_all(&event->waitq);
4509 static void ring_buffer_wakeup(struct perf_event *event)
4511 struct ring_buffer *rb;
4514 rb = rcu_dereference(event->rb);
4516 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4517 wake_up_all(&event->waitq);
4522 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4524 struct ring_buffer *rb;
4527 rb = rcu_dereference(event->rb);
4529 if (!atomic_inc_not_zero(&rb->refcount))
4537 void ring_buffer_put(struct ring_buffer *rb)
4539 if (!atomic_dec_and_test(&rb->refcount))
4542 WARN_ON_ONCE(!list_empty(&rb->event_list));
4544 call_rcu(&rb->rcu_head, rb_free_rcu);
4547 static void perf_mmap_open(struct vm_area_struct *vma)
4549 struct perf_event *event = vma->vm_file->private_data;
4551 atomic_inc(&event->mmap_count);
4552 atomic_inc(&event->rb->mmap_count);
4555 atomic_inc(&event->rb->aux_mmap_count);
4557 if (event->pmu->event_mapped)
4558 event->pmu->event_mapped(event);
4562 * A buffer can be mmap()ed multiple times; either directly through the same
4563 * event, or through other events by use of perf_event_set_output().
4565 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4566 * the buffer here, where we still have a VM context. This means we need
4567 * to detach all events redirecting to us.
4569 static void perf_mmap_close(struct vm_area_struct *vma)
4571 struct perf_event *event = vma->vm_file->private_data;
4573 struct ring_buffer *rb = ring_buffer_get(event);
4574 struct user_struct *mmap_user = rb->mmap_user;
4575 int mmap_locked = rb->mmap_locked;
4576 unsigned long size = perf_data_size(rb);
4578 if (event->pmu->event_unmapped)
4579 event->pmu->event_unmapped(event);
4582 * rb->aux_mmap_count will always drop before rb->mmap_count and
4583 * event->mmap_count, so it is ok to use event->mmap_mutex to
4584 * serialize with perf_mmap here.
4586 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4587 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4588 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4589 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4592 mutex_unlock(&event->mmap_mutex);
4595 atomic_dec(&rb->mmap_count);
4597 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4600 ring_buffer_attach(event, NULL);
4601 mutex_unlock(&event->mmap_mutex);
4603 /* If there's still other mmap()s of this buffer, we're done. */
4604 if (atomic_read(&rb->mmap_count))
4608 * No other mmap()s, detach from all other events that might redirect
4609 * into the now unreachable buffer. Somewhat complicated by the
4610 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4614 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4615 if (!atomic_long_inc_not_zero(&event->refcount)) {
4617 * This event is en-route to free_event() which will
4618 * detach it and remove it from the list.
4624 mutex_lock(&event->mmap_mutex);
4626 * Check we didn't race with perf_event_set_output() which can
4627 * swizzle the rb from under us while we were waiting to
4628 * acquire mmap_mutex.
4630 * If we find a different rb; ignore this event, a next
4631 * iteration will no longer find it on the list. We have to
4632 * still restart the iteration to make sure we're not now
4633 * iterating the wrong list.
4635 if (event->rb == rb)
4636 ring_buffer_attach(event, NULL);
4638 mutex_unlock(&event->mmap_mutex);
4642 * Restart the iteration; either we're on the wrong list or
4643 * destroyed its integrity by doing a deletion.
4650 * It could be there's still a few 0-ref events on the list; they'll
4651 * get cleaned up by free_event() -- they'll also still have their
4652 * ref on the rb and will free it whenever they are done with it.
4654 * Aside from that, this buffer is 'fully' detached and unmapped,
4655 * undo the VM accounting.
4658 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4659 vma->vm_mm->pinned_vm -= mmap_locked;
4660 free_uid(mmap_user);
4663 ring_buffer_put(rb); /* could be last */
4666 static const struct vm_operations_struct perf_mmap_vmops = {
4667 .open = perf_mmap_open,
4668 .close = perf_mmap_close, /* non mergable */
4669 .fault = perf_mmap_fault,
4670 .page_mkwrite = perf_mmap_fault,
4673 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4675 struct perf_event *event = file->private_data;
4676 unsigned long user_locked, user_lock_limit;
4677 struct user_struct *user = current_user();
4678 unsigned long locked, lock_limit;
4679 struct ring_buffer *rb = NULL;
4680 unsigned long vma_size;
4681 unsigned long nr_pages;
4682 long user_extra = 0, extra = 0;
4683 int ret = 0, flags = 0;
4686 * Don't allow mmap() of inherited per-task counters. This would
4687 * create a performance issue due to all children writing to the
4690 if (event->cpu == -1 && event->attr.inherit)
4693 if (!(vma->vm_flags & VM_SHARED))
4696 vma_size = vma->vm_end - vma->vm_start;
4698 if (vma->vm_pgoff == 0) {
4699 nr_pages = (vma_size / PAGE_SIZE) - 1;
4702 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4703 * mapped, all subsequent mappings should have the same size
4704 * and offset. Must be above the normal perf buffer.
4706 u64 aux_offset, aux_size;
4711 nr_pages = vma_size / PAGE_SIZE;
4713 mutex_lock(&event->mmap_mutex);
4720 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4721 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4723 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4726 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4729 /* already mapped with a different offset */
4730 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4733 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4736 /* already mapped with a different size */
4737 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4740 if (!is_power_of_2(nr_pages))
4743 if (!atomic_inc_not_zero(&rb->mmap_count))
4746 if (rb_has_aux(rb)) {
4747 atomic_inc(&rb->aux_mmap_count);
4752 atomic_set(&rb->aux_mmap_count, 1);
4753 user_extra = nr_pages;
4759 * If we have rb pages ensure they're a power-of-two number, so we
4760 * can do bitmasks instead of modulo.
4762 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4765 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4768 WARN_ON_ONCE(event->ctx->parent_ctx);
4770 mutex_lock(&event->mmap_mutex);
4772 if (event->rb->nr_pages != nr_pages) {
4777 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4779 * Raced against perf_mmap_close() through
4780 * perf_event_set_output(). Try again, hope for better
4783 mutex_unlock(&event->mmap_mutex);
4790 user_extra = nr_pages + 1;
4793 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4796 * Increase the limit linearly with more CPUs:
4798 user_lock_limit *= num_online_cpus();
4800 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4802 if (user_locked > user_lock_limit)
4803 extra = user_locked - user_lock_limit;
4805 lock_limit = rlimit(RLIMIT_MEMLOCK);
4806 lock_limit >>= PAGE_SHIFT;
4807 locked = vma->vm_mm->pinned_vm + extra;
4809 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4810 !capable(CAP_IPC_LOCK)) {
4815 WARN_ON(!rb && event->rb);
4817 if (vma->vm_flags & VM_WRITE)
4818 flags |= RING_BUFFER_WRITABLE;
4821 rb = rb_alloc(nr_pages,
4822 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4830 atomic_set(&rb->mmap_count, 1);
4831 rb->mmap_user = get_current_user();
4832 rb->mmap_locked = extra;
4834 ring_buffer_attach(event, rb);
4836 perf_event_init_userpage(event);
4837 perf_event_update_userpage(event);
4839 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4840 event->attr.aux_watermark, flags);
4842 rb->aux_mmap_locked = extra;
4847 atomic_long_add(user_extra, &user->locked_vm);
4848 vma->vm_mm->pinned_vm += extra;
4850 atomic_inc(&event->mmap_count);
4852 atomic_dec(&rb->mmap_count);
4855 mutex_unlock(&event->mmap_mutex);
4858 * Since pinned accounting is per vm we cannot allow fork() to copy our
4861 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4862 vma->vm_ops = &perf_mmap_vmops;
4864 if (event->pmu->event_mapped)
4865 event->pmu->event_mapped(event);
4870 static int perf_fasync(int fd, struct file *filp, int on)
4872 struct inode *inode = file_inode(filp);
4873 struct perf_event *event = filp->private_data;
4877 retval = fasync_helper(fd, filp, on, &event->fasync);
4878 inode_unlock(inode);
4886 static const struct file_operations perf_fops = {
4887 .llseek = no_llseek,
4888 .release = perf_release,
4891 .unlocked_ioctl = perf_ioctl,
4892 .compat_ioctl = perf_compat_ioctl,
4894 .fasync = perf_fasync,
4900 * If there's data, ensure we set the poll() state and publish everything
4901 * to user-space before waking everybody up.
4904 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4906 /* only the parent has fasync state */
4908 event = event->parent;
4909 return &event->fasync;
4912 void perf_event_wakeup(struct perf_event *event)
4914 ring_buffer_wakeup(event);
4916 if (event->pending_kill) {
4917 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4918 event->pending_kill = 0;
4922 static void perf_pending_event(struct irq_work *entry)
4924 struct perf_event *event = container_of(entry,
4925 struct perf_event, pending);
4928 rctx = perf_swevent_get_recursion_context();
4930 * If we 'fail' here, that's OK, it means recursion is already disabled
4931 * and we won't recurse 'further'.
4934 if (event->pending_disable) {
4935 event->pending_disable = 0;
4936 perf_event_disable_local(event);
4939 if (event->pending_wakeup) {
4940 event->pending_wakeup = 0;
4941 perf_event_wakeup(event);
4945 perf_swevent_put_recursion_context(rctx);
4949 * We assume there is only KVM supporting the callbacks.
4950 * Later on, we might change it to a list if there is
4951 * another virtualization implementation supporting the callbacks.
4953 struct perf_guest_info_callbacks *perf_guest_cbs;
4955 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4957 perf_guest_cbs = cbs;
4960 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4962 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4964 perf_guest_cbs = NULL;
4967 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4970 perf_output_sample_regs(struct perf_output_handle *handle,
4971 struct pt_regs *regs, u64 mask)
4975 for_each_set_bit(bit, (const unsigned long *) &mask,
4976 sizeof(mask) * BITS_PER_BYTE) {
4979 val = perf_reg_value(regs, bit);
4980 perf_output_put(handle, val);
4984 static void perf_sample_regs_user(struct perf_regs *regs_user,
4985 struct pt_regs *regs,
4986 struct pt_regs *regs_user_copy)
4988 if (user_mode(regs)) {
4989 regs_user->abi = perf_reg_abi(current);
4990 regs_user->regs = regs;
4991 } else if (current->mm) {
4992 perf_get_regs_user(regs_user, regs, regs_user_copy);
4994 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4995 regs_user->regs = NULL;
4999 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5000 struct pt_regs *regs)
5002 regs_intr->regs = regs;
5003 regs_intr->abi = perf_reg_abi(current);
5008 * Get remaining task size from user stack pointer.
5010 * It'd be better to take stack vma map and limit this more
5011 * precisly, but there's no way to get it safely under interrupt,
5012 * so using TASK_SIZE as limit.
5014 static u64 perf_ustack_task_size(struct pt_regs *regs)
5016 unsigned long addr = perf_user_stack_pointer(regs);
5018 if (!addr || addr >= TASK_SIZE)
5021 return TASK_SIZE - addr;
5025 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5026 struct pt_regs *regs)
5030 /* No regs, no stack pointer, no dump. */
5035 * Check if we fit in with the requested stack size into the:
5037 * If we don't, we limit the size to the TASK_SIZE.
5039 * - remaining sample size
5040 * If we don't, we customize the stack size to
5041 * fit in to the remaining sample size.
5044 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5045 stack_size = min(stack_size, (u16) task_size);
5047 /* Current header size plus static size and dynamic size. */
5048 header_size += 2 * sizeof(u64);
5050 /* Do we fit in with the current stack dump size? */
5051 if ((u16) (header_size + stack_size) < header_size) {
5053 * If we overflow the maximum size for the sample,
5054 * we customize the stack dump size to fit in.
5056 stack_size = USHRT_MAX - header_size - sizeof(u64);
5057 stack_size = round_up(stack_size, sizeof(u64));
5064 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5065 struct pt_regs *regs)
5067 /* Case of a kernel thread, nothing to dump */
5070 perf_output_put(handle, size);
5079 * - the size requested by user or the best one we can fit
5080 * in to the sample max size
5082 * - user stack dump data
5084 * - the actual dumped size
5088 perf_output_put(handle, dump_size);
5091 sp = perf_user_stack_pointer(regs);
5092 rem = __output_copy_user(handle, (void *) sp, dump_size);
5093 dyn_size = dump_size - rem;
5095 perf_output_skip(handle, rem);
5098 perf_output_put(handle, dyn_size);
5102 static void __perf_event_header__init_id(struct perf_event_header *header,
5103 struct perf_sample_data *data,
5104 struct perf_event *event)
5106 u64 sample_type = event->attr.sample_type;
5108 data->type = sample_type;
5109 header->size += event->id_header_size;
5111 if (sample_type & PERF_SAMPLE_TID) {
5112 /* namespace issues */
5113 data->tid_entry.pid = perf_event_pid(event, current);
5114 data->tid_entry.tid = perf_event_tid(event, current);
5117 if (sample_type & PERF_SAMPLE_TIME)
5118 data->time = perf_event_clock(event);
5120 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5121 data->id = primary_event_id(event);
5123 if (sample_type & PERF_SAMPLE_STREAM_ID)
5124 data->stream_id = event->id;
5126 if (sample_type & PERF_SAMPLE_CPU) {
5127 data->cpu_entry.cpu = raw_smp_processor_id();
5128 data->cpu_entry.reserved = 0;
5132 void perf_event_header__init_id(struct perf_event_header *header,
5133 struct perf_sample_data *data,
5134 struct perf_event *event)
5136 if (event->attr.sample_id_all)
5137 __perf_event_header__init_id(header, data, event);
5140 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5141 struct perf_sample_data *data)
5143 u64 sample_type = data->type;
5145 if (sample_type & PERF_SAMPLE_TID)
5146 perf_output_put(handle, data->tid_entry);
5148 if (sample_type & PERF_SAMPLE_TIME)
5149 perf_output_put(handle, data->time);
5151 if (sample_type & PERF_SAMPLE_ID)
5152 perf_output_put(handle, data->id);
5154 if (sample_type & PERF_SAMPLE_STREAM_ID)
5155 perf_output_put(handle, data->stream_id);
5157 if (sample_type & PERF_SAMPLE_CPU)
5158 perf_output_put(handle, data->cpu_entry);
5160 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5161 perf_output_put(handle, data->id);
5164 void perf_event__output_id_sample(struct perf_event *event,
5165 struct perf_output_handle *handle,
5166 struct perf_sample_data *sample)
5168 if (event->attr.sample_id_all)
5169 __perf_event__output_id_sample(handle, sample);
5172 static void perf_output_read_one(struct perf_output_handle *handle,
5173 struct perf_event *event,
5174 u64 enabled, u64 running)
5176 u64 read_format = event->attr.read_format;
5180 values[n++] = perf_event_count(event);
5181 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5182 values[n++] = enabled +
5183 atomic64_read(&event->child_total_time_enabled);
5185 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5186 values[n++] = running +
5187 atomic64_read(&event->child_total_time_running);
5189 if (read_format & PERF_FORMAT_ID)
5190 values[n++] = primary_event_id(event);
5192 __output_copy(handle, values, n * sizeof(u64));
5196 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5198 static void perf_output_read_group(struct perf_output_handle *handle,
5199 struct perf_event *event,
5200 u64 enabled, u64 running)
5202 struct perf_event *leader = event->group_leader, *sub;
5203 u64 read_format = event->attr.read_format;
5207 values[n++] = 1 + leader->nr_siblings;
5209 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5210 values[n++] = enabled;
5212 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5213 values[n++] = running;
5215 if (leader != event)
5216 leader->pmu->read(leader);
5218 values[n++] = perf_event_count(leader);
5219 if (read_format & PERF_FORMAT_ID)
5220 values[n++] = primary_event_id(leader);
5222 __output_copy(handle, values, n * sizeof(u64));
5224 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5227 if ((sub != event) &&
5228 (sub->state == PERF_EVENT_STATE_ACTIVE))
5229 sub->pmu->read(sub);
5231 values[n++] = perf_event_count(sub);
5232 if (read_format & PERF_FORMAT_ID)
5233 values[n++] = primary_event_id(sub);
5235 __output_copy(handle, values, n * sizeof(u64));
5239 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5240 PERF_FORMAT_TOTAL_TIME_RUNNING)
5242 static void perf_output_read(struct perf_output_handle *handle,
5243 struct perf_event *event)
5245 u64 enabled = 0, running = 0, now;
5246 u64 read_format = event->attr.read_format;
5249 * compute total_time_enabled, total_time_running
5250 * based on snapshot values taken when the event
5251 * was last scheduled in.
5253 * we cannot simply called update_context_time()
5254 * because of locking issue as we are called in
5257 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5258 calc_timer_values(event, &now, &enabled, &running);
5260 if (event->attr.read_format & PERF_FORMAT_GROUP)
5261 perf_output_read_group(handle, event, enabled, running);
5263 perf_output_read_one(handle, event, enabled, running);
5266 void perf_output_sample(struct perf_output_handle *handle,
5267 struct perf_event_header *header,
5268 struct perf_sample_data *data,
5269 struct perf_event *event)
5271 u64 sample_type = data->type;
5273 perf_output_put(handle, *header);
5275 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5276 perf_output_put(handle, data->id);
5278 if (sample_type & PERF_SAMPLE_IP)
5279 perf_output_put(handle, data->ip);
5281 if (sample_type & PERF_SAMPLE_TID)
5282 perf_output_put(handle, data->tid_entry);
5284 if (sample_type & PERF_SAMPLE_TIME)
5285 perf_output_put(handle, data->time);
5287 if (sample_type & PERF_SAMPLE_ADDR)
5288 perf_output_put(handle, data->addr);
5290 if (sample_type & PERF_SAMPLE_ID)
5291 perf_output_put(handle, data->id);
5293 if (sample_type & PERF_SAMPLE_STREAM_ID)
5294 perf_output_put(handle, data->stream_id);
5296 if (sample_type & PERF_SAMPLE_CPU)
5297 perf_output_put(handle, data->cpu_entry);
5299 if (sample_type & PERF_SAMPLE_PERIOD)
5300 perf_output_put(handle, data->period);
5302 if (sample_type & PERF_SAMPLE_READ)
5303 perf_output_read(handle, event);
5305 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5306 if (data->callchain) {
5309 if (data->callchain)
5310 size += data->callchain->nr;
5312 size *= sizeof(u64);
5314 __output_copy(handle, data->callchain, size);
5317 perf_output_put(handle, nr);
5321 if (sample_type & PERF_SAMPLE_RAW) {
5323 u32 raw_size = data->raw->size;
5324 u32 real_size = round_up(raw_size + sizeof(u32),
5325 sizeof(u64)) - sizeof(u32);
5328 perf_output_put(handle, real_size);
5329 __output_copy(handle, data->raw->data, raw_size);
5330 if (real_size - raw_size)
5331 __output_copy(handle, &zero, real_size - raw_size);
5337 .size = sizeof(u32),
5340 perf_output_put(handle, raw);
5344 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5345 if (data->br_stack) {
5348 size = data->br_stack->nr
5349 * sizeof(struct perf_branch_entry);
5351 perf_output_put(handle, data->br_stack->nr);
5352 perf_output_copy(handle, data->br_stack->entries, size);
5355 * we always store at least the value of nr
5358 perf_output_put(handle, nr);
5362 if (sample_type & PERF_SAMPLE_REGS_USER) {
5363 u64 abi = data->regs_user.abi;
5366 * If there are no regs to dump, notice it through
5367 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5369 perf_output_put(handle, abi);
5372 u64 mask = event->attr.sample_regs_user;
5373 perf_output_sample_regs(handle,
5374 data->regs_user.regs,
5379 if (sample_type & PERF_SAMPLE_STACK_USER) {
5380 perf_output_sample_ustack(handle,
5381 data->stack_user_size,
5382 data->regs_user.regs);
5385 if (sample_type & PERF_SAMPLE_WEIGHT)
5386 perf_output_put(handle, data->weight);
5388 if (sample_type & PERF_SAMPLE_DATA_SRC)
5389 perf_output_put(handle, data->data_src.val);
5391 if (sample_type & PERF_SAMPLE_TRANSACTION)
5392 perf_output_put(handle, data->txn);
5394 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5395 u64 abi = data->regs_intr.abi;
5397 * If there are no regs to dump, notice it through
5398 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5400 perf_output_put(handle, abi);
5403 u64 mask = event->attr.sample_regs_intr;
5405 perf_output_sample_regs(handle,
5406 data->regs_intr.regs,
5411 if (!event->attr.watermark) {
5412 int wakeup_events = event->attr.wakeup_events;
5414 if (wakeup_events) {
5415 struct ring_buffer *rb = handle->rb;
5416 int events = local_inc_return(&rb->events);
5418 if (events >= wakeup_events) {
5419 local_sub(wakeup_events, &rb->events);
5420 local_inc(&rb->wakeup);
5426 void perf_prepare_sample(struct perf_event_header *header,
5427 struct perf_sample_data *data,
5428 struct perf_event *event,
5429 struct pt_regs *regs)
5431 u64 sample_type = event->attr.sample_type;
5433 header->type = PERF_RECORD_SAMPLE;
5434 header->size = sizeof(*header) + event->header_size;
5437 header->misc |= perf_misc_flags(regs);
5439 __perf_event_header__init_id(header, data, event);
5441 if (sample_type & PERF_SAMPLE_IP)
5442 data->ip = perf_instruction_pointer(regs);
5444 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5447 data->callchain = perf_callchain(event, regs);
5449 if (data->callchain)
5450 size += data->callchain->nr;
5452 header->size += size * sizeof(u64);
5455 if (sample_type & PERF_SAMPLE_RAW) {
5456 int size = sizeof(u32);
5459 size += data->raw->size;
5461 size += sizeof(u32);
5463 header->size += round_up(size, sizeof(u64));
5466 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5467 int size = sizeof(u64); /* nr */
5468 if (data->br_stack) {
5469 size += data->br_stack->nr
5470 * sizeof(struct perf_branch_entry);
5472 header->size += size;
5475 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5476 perf_sample_regs_user(&data->regs_user, regs,
5477 &data->regs_user_copy);
5479 if (sample_type & PERF_SAMPLE_REGS_USER) {
5480 /* regs dump ABI info */
5481 int size = sizeof(u64);
5483 if (data->regs_user.regs) {
5484 u64 mask = event->attr.sample_regs_user;
5485 size += hweight64(mask) * sizeof(u64);
5488 header->size += size;
5491 if (sample_type & PERF_SAMPLE_STACK_USER) {
5493 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5494 * processed as the last one or have additional check added
5495 * in case new sample type is added, because we could eat
5496 * up the rest of the sample size.
5498 u16 stack_size = event->attr.sample_stack_user;
5499 u16 size = sizeof(u64);
5501 stack_size = perf_sample_ustack_size(stack_size, header->size,
5502 data->regs_user.regs);
5505 * If there is something to dump, add space for the dump
5506 * itself and for the field that tells the dynamic size,
5507 * which is how many have been actually dumped.
5510 size += sizeof(u64) + stack_size;
5512 data->stack_user_size = stack_size;
5513 header->size += size;
5516 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5517 /* regs dump ABI info */
5518 int size = sizeof(u64);
5520 perf_sample_regs_intr(&data->regs_intr, regs);
5522 if (data->regs_intr.regs) {
5523 u64 mask = event->attr.sample_regs_intr;
5525 size += hweight64(mask) * sizeof(u64);
5528 header->size += size;
5532 void perf_event_output(struct perf_event *event,
5533 struct perf_sample_data *data,
5534 struct pt_regs *regs)
5536 struct perf_output_handle handle;
5537 struct perf_event_header header;
5539 /* protect the callchain buffers */
5542 perf_prepare_sample(&header, data, event, regs);
5544 if (perf_output_begin(&handle, event, header.size))
5547 perf_output_sample(&handle, &header, data, event);
5549 perf_output_end(&handle);
5559 struct perf_read_event {
5560 struct perf_event_header header;
5567 perf_event_read_event(struct perf_event *event,
5568 struct task_struct *task)
5570 struct perf_output_handle handle;
5571 struct perf_sample_data sample;
5572 struct perf_read_event read_event = {
5574 .type = PERF_RECORD_READ,
5576 .size = sizeof(read_event) + event->read_size,
5578 .pid = perf_event_pid(event, task),
5579 .tid = perf_event_tid(event, task),
5583 perf_event_header__init_id(&read_event.header, &sample, event);
5584 ret = perf_output_begin(&handle, event, read_event.header.size);
5588 perf_output_put(&handle, read_event);
5589 perf_output_read(&handle, event);
5590 perf_event__output_id_sample(event, &handle, &sample);
5592 perf_output_end(&handle);
5595 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5598 perf_event_aux_ctx(struct perf_event_context *ctx,
5599 perf_event_aux_output_cb output,
5602 struct perf_event *event;
5604 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5605 if (event->state < PERF_EVENT_STATE_INACTIVE)
5607 if (!event_filter_match(event))
5609 output(event, data);
5614 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5615 struct perf_event_context *task_ctx)
5619 perf_event_aux_ctx(task_ctx, output, data);
5625 perf_event_aux(perf_event_aux_output_cb output, void *data,
5626 struct perf_event_context *task_ctx)
5628 struct perf_cpu_context *cpuctx;
5629 struct perf_event_context *ctx;
5634 * If we have task_ctx != NULL we only notify
5635 * the task context itself. The task_ctx is set
5636 * only for EXIT events before releasing task
5640 perf_event_aux_task_ctx(output, data, task_ctx);
5645 list_for_each_entry_rcu(pmu, &pmus, entry) {
5646 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5647 if (cpuctx->unique_pmu != pmu)
5649 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5650 ctxn = pmu->task_ctx_nr;
5653 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5655 perf_event_aux_ctx(ctx, output, data);
5657 put_cpu_ptr(pmu->pmu_cpu_context);
5663 * task tracking -- fork/exit
5665 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5668 struct perf_task_event {
5669 struct task_struct *task;
5670 struct perf_event_context *task_ctx;
5673 struct perf_event_header header;
5683 static int perf_event_task_match(struct perf_event *event)
5685 return event->attr.comm || event->attr.mmap ||
5686 event->attr.mmap2 || event->attr.mmap_data ||
5690 static void perf_event_task_output(struct perf_event *event,
5693 struct perf_task_event *task_event = data;
5694 struct perf_output_handle handle;
5695 struct perf_sample_data sample;
5696 struct task_struct *task = task_event->task;
5697 int ret, size = task_event->event_id.header.size;
5699 if (!perf_event_task_match(event))
5702 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5704 ret = perf_output_begin(&handle, event,
5705 task_event->event_id.header.size);
5709 task_event->event_id.pid = perf_event_pid(event, task);
5710 task_event->event_id.ppid = perf_event_pid(event, current);
5712 task_event->event_id.tid = perf_event_tid(event, task);
5713 task_event->event_id.ptid = perf_event_tid(event, current);
5715 task_event->event_id.time = perf_event_clock(event);
5717 perf_output_put(&handle, task_event->event_id);
5719 perf_event__output_id_sample(event, &handle, &sample);
5721 perf_output_end(&handle);
5723 task_event->event_id.header.size = size;
5726 static void perf_event_task(struct task_struct *task,
5727 struct perf_event_context *task_ctx,
5730 struct perf_task_event task_event;
5732 if (!atomic_read(&nr_comm_events) &&
5733 !atomic_read(&nr_mmap_events) &&
5734 !atomic_read(&nr_task_events))
5737 task_event = (struct perf_task_event){
5739 .task_ctx = task_ctx,
5742 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5744 .size = sizeof(task_event.event_id),
5754 perf_event_aux(perf_event_task_output,
5759 void perf_event_fork(struct task_struct *task)
5761 perf_event_task(task, NULL, 1);
5768 struct perf_comm_event {
5769 struct task_struct *task;
5774 struct perf_event_header header;
5781 static int perf_event_comm_match(struct perf_event *event)
5783 return event->attr.comm;
5786 static void perf_event_comm_output(struct perf_event *event,
5789 struct perf_comm_event *comm_event = data;
5790 struct perf_output_handle handle;
5791 struct perf_sample_data sample;
5792 int size = comm_event->event_id.header.size;
5795 if (!perf_event_comm_match(event))
5798 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5799 ret = perf_output_begin(&handle, event,
5800 comm_event->event_id.header.size);
5805 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5806 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5808 perf_output_put(&handle, comm_event->event_id);
5809 __output_copy(&handle, comm_event->comm,
5810 comm_event->comm_size);
5812 perf_event__output_id_sample(event, &handle, &sample);
5814 perf_output_end(&handle);
5816 comm_event->event_id.header.size = size;
5819 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5821 char comm[TASK_COMM_LEN];
5824 memset(comm, 0, sizeof(comm));
5825 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5826 size = ALIGN(strlen(comm)+1, sizeof(u64));
5828 comm_event->comm = comm;
5829 comm_event->comm_size = size;
5831 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5833 perf_event_aux(perf_event_comm_output,
5838 void perf_event_comm(struct task_struct *task, bool exec)
5840 struct perf_comm_event comm_event;
5842 if (!atomic_read(&nr_comm_events))
5845 comm_event = (struct perf_comm_event){
5851 .type = PERF_RECORD_COMM,
5852 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5860 perf_event_comm_event(&comm_event);
5867 struct perf_mmap_event {
5868 struct vm_area_struct *vma;
5870 const char *file_name;
5878 struct perf_event_header header;
5888 static int perf_event_mmap_match(struct perf_event *event,
5891 struct perf_mmap_event *mmap_event = data;
5892 struct vm_area_struct *vma = mmap_event->vma;
5893 int executable = vma->vm_flags & VM_EXEC;
5895 return (!executable && event->attr.mmap_data) ||
5896 (executable && (event->attr.mmap || event->attr.mmap2));
5899 static void perf_event_mmap_output(struct perf_event *event,
5902 struct perf_mmap_event *mmap_event = data;
5903 struct perf_output_handle handle;
5904 struct perf_sample_data sample;
5905 int size = mmap_event->event_id.header.size;
5908 if (!perf_event_mmap_match(event, data))
5911 if (event->attr.mmap2) {
5912 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5913 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5914 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5915 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5916 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5917 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5918 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5921 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5922 ret = perf_output_begin(&handle, event,
5923 mmap_event->event_id.header.size);
5927 mmap_event->event_id.pid = perf_event_pid(event, current);
5928 mmap_event->event_id.tid = perf_event_tid(event, current);
5930 perf_output_put(&handle, mmap_event->event_id);
5932 if (event->attr.mmap2) {
5933 perf_output_put(&handle, mmap_event->maj);
5934 perf_output_put(&handle, mmap_event->min);
5935 perf_output_put(&handle, mmap_event->ino);
5936 perf_output_put(&handle, mmap_event->ino_generation);
5937 perf_output_put(&handle, mmap_event->prot);
5938 perf_output_put(&handle, mmap_event->flags);
5941 __output_copy(&handle, mmap_event->file_name,
5942 mmap_event->file_size);
5944 perf_event__output_id_sample(event, &handle, &sample);
5946 perf_output_end(&handle);
5948 mmap_event->event_id.header.size = size;
5951 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5953 struct vm_area_struct *vma = mmap_event->vma;
5954 struct file *file = vma->vm_file;
5955 int maj = 0, min = 0;
5956 u64 ino = 0, gen = 0;
5957 u32 prot = 0, flags = 0;
5964 struct inode *inode;
5967 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5973 * d_path() works from the end of the rb backwards, so we
5974 * need to add enough zero bytes after the string to handle
5975 * the 64bit alignment we do later.
5977 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5982 inode = file_inode(vma->vm_file);
5983 dev = inode->i_sb->s_dev;
5985 gen = inode->i_generation;
5989 if (vma->vm_flags & VM_READ)
5991 if (vma->vm_flags & VM_WRITE)
5993 if (vma->vm_flags & VM_EXEC)
5996 if (vma->vm_flags & VM_MAYSHARE)
5999 flags = MAP_PRIVATE;
6001 if (vma->vm_flags & VM_DENYWRITE)
6002 flags |= MAP_DENYWRITE;
6003 if (vma->vm_flags & VM_MAYEXEC)
6004 flags |= MAP_EXECUTABLE;
6005 if (vma->vm_flags & VM_LOCKED)
6006 flags |= MAP_LOCKED;
6007 if (vma->vm_flags & VM_HUGETLB)
6008 flags |= MAP_HUGETLB;
6012 if (vma->vm_ops && vma->vm_ops->name) {
6013 name = (char *) vma->vm_ops->name(vma);
6018 name = (char *)arch_vma_name(vma);
6022 if (vma->vm_start <= vma->vm_mm->start_brk &&
6023 vma->vm_end >= vma->vm_mm->brk) {
6027 if (vma->vm_start <= vma->vm_mm->start_stack &&
6028 vma->vm_end >= vma->vm_mm->start_stack) {
6038 strlcpy(tmp, name, sizeof(tmp));
6042 * Since our buffer works in 8 byte units we need to align our string
6043 * size to a multiple of 8. However, we must guarantee the tail end is
6044 * zero'd out to avoid leaking random bits to userspace.
6046 size = strlen(name)+1;
6047 while (!IS_ALIGNED(size, sizeof(u64)))
6048 name[size++] = '\0';
6050 mmap_event->file_name = name;
6051 mmap_event->file_size = size;
6052 mmap_event->maj = maj;
6053 mmap_event->min = min;
6054 mmap_event->ino = ino;
6055 mmap_event->ino_generation = gen;
6056 mmap_event->prot = prot;
6057 mmap_event->flags = flags;
6059 if (!(vma->vm_flags & VM_EXEC))
6060 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6062 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6064 perf_event_aux(perf_event_mmap_output,
6071 void perf_event_mmap(struct vm_area_struct *vma)
6073 struct perf_mmap_event mmap_event;
6075 if (!atomic_read(&nr_mmap_events))
6078 mmap_event = (struct perf_mmap_event){
6084 .type = PERF_RECORD_MMAP,
6085 .misc = PERF_RECORD_MISC_USER,
6090 .start = vma->vm_start,
6091 .len = vma->vm_end - vma->vm_start,
6092 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6094 /* .maj (attr_mmap2 only) */
6095 /* .min (attr_mmap2 only) */
6096 /* .ino (attr_mmap2 only) */
6097 /* .ino_generation (attr_mmap2 only) */
6098 /* .prot (attr_mmap2 only) */
6099 /* .flags (attr_mmap2 only) */
6102 perf_event_mmap_event(&mmap_event);
6105 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6106 unsigned long size, u64 flags)
6108 struct perf_output_handle handle;
6109 struct perf_sample_data sample;
6110 struct perf_aux_event {
6111 struct perf_event_header header;
6117 .type = PERF_RECORD_AUX,
6119 .size = sizeof(rec),
6127 perf_event_header__init_id(&rec.header, &sample, event);
6128 ret = perf_output_begin(&handle, event, rec.header.size);
6133 perf_output_put(&handle, rec);
6134 perf_event__output_id_sample(event, &handle, &sample);
6136 perf_output_end(&handle);
6140 * Lost/dropped samples logging
6142 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6144 struct perf_output_handle handle;
6145 struct perf_sample_data sample;
6149 struct perf_event_header header;
6151 } lost_samples_event = {
6153 .type = PERF_RECORD_LOST_SAMPLES,
6155 .size = sizeof(lost_samples_event),
6160 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6162 ret = perf_output_begin(&handle, event,
6163 lost_samples_event.header.size);
6167 perf_output_put(&handle, lost_samples_event);
6168 perf_event__output_id_sample(event, &handle, &sample);
6169 perf_output_end(&handle);
6173 * context_switch tracking
6176 struct perf_switch_event {
6177 struct task_struct *task;
6178 struct task_struct *next_prev;
6181 struct perf_event_header header;
6187 static int perf_event_switch_match(struct perf_event *event)
6189 return event->attr.context_switch;
6192 static void perf_event_switch_output(struct perf_event *event, void *data)
6194 struct perf_switch_event *se = data;
6195 struct perf_output_handle handle;
6196 struct perf_sample_data sample;
6199 if (!perf_event_switch_match(event))
6202 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6203 if (event->ctx->task) {
6204 se->event_id.header.type = PERF_RECORD_SWITCH;
6205 se->event_id.header.size = sizeof(se->event_id.header);
6207 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6208 se->event_id.header.size = sizeof(se->event_id);
6209 se->event_id.next_prev_pid =
6210 perf_event_pid(event, se->next_prev);
6211 se->event_id.next_prev_tid =
6212 perf_event_tid(event, se->next_prev);
6215 perf_event_header__init_id(&se->event_id.header, &sample, event);
6217 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6221 if (event->ctx->task)
6222 perf_output_put(&handle, se->event_id.header);
6224 perf_output_put(&handle, se->event_id);
6226 perf_event__output_id_sample(event, &handle, &sample);
6228 perf_output_end(&handle);
6231 static void perf_event_switch(struct task_struct *task,
6232 struct task_struct *next_prev, bool sched_in)
6234 struct perf_switch_event switch_event;
6236 /* N.B. caller checks nr_switch_events != 0 */
6238 switch_event = (struct perf_switch_event){
6240 .next_prev = next_prev,
6244 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6247 /* .next_prev_pid */
6248 /* .next_prev_tid */
6252 perf_event_aux(perf_event_switch_output,
6258 * IRQ throttle logging
6261 static void perf_log_throttle(struct perf_event *event, int enable)
6263 struct perf_output_handle handle;
6264 struct perf_sample_data sample;
6268 struct perf_event_header header;
6272 } throttle_event = {
6274 .type = PERF_RECORD_THROTTLE,
6276 .size = sizeof(throttle_event),
6278 .time = perf_event_clock(event),
6279 .id = primary_event_id(event),
6280 .stream_id = event->id,
6284 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6286 perf_event_header__init_id(&throttle_event.header, &sample, event);
6288 ret = perf_output_begin(&handle, event,
6289 throttle_event.header.size);
6293 perf_output_put(&handle, throttle_event);
6294 perf_event__output_id_sample(event, &handle, &sample);
6295 perf_output_end(&handle);
6298 static void perf_log_itrace_start(struct perf_event *event)
6300 struct perf_output_handle handle;
6301 struct perf_sample_data sample;
6302 struct perf_aux_event {
6303 struct perf_event_header header;
6310 event = event->parent;
6312 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6313 event->hw.itrace_started)
6316 rec.header.type = PERF_RECORD_ITRACE_START;
6317 rec.header.misc = 0;
6318 rec.header.size = sizeof(rec);
6319 rec.pid = perf_event_pid(event, current);
6320 rec.tid = perf_event_tid(event, current);
6322 perf_event_header__init_id(&rec.header, &sample, event);
6323 ret = perf_output_begin(&handle, event, rec.header.size);
6328 perf_output_put(&handle, rec);
6329 perf_event__output_id_sample(event, &handle, &sample);
6331 perf_output_end(&handle);
6335 * Generic event overflow handling, sampling.
6338 static int __perf_event_overflow(struct perf_event *event,
6339 int throttle, struct perf_sample_data *data,
6340 struct pt_regs *regs)
6342 int events = atomic_read(&event->event_limit);
6343 struct hw_perf_event *hwc = &event->hw;
6348 * Non-sampling counters might still use the PMI to fold short
6349 * hardware counters, ignore those.
6351 if (unlikely(!is_sampling_event(event)))
6354 seq = __this_cpu_read(perf_throttled_seq);
6355 if (seq != hwc->interrupts_seq) {
6356 hwc->interrupts_seq = seq;
6357 hwc->interrupts = 1;
6360 if (unlikely(throttle
6361 && hwc->interrupts >= max_samples_per_tick)) {
6362 __this_cpu_inc(perf_throttled_count);
6363 hwc->interrupts = MAX_INTERRUPTS;
6364 perf_log_throttle(event, 0);
6365 tick_nohz_full_kick();
6370 if (event->attr.freq) {
6371 u64 now = perf_clock();
6372 s64 delta = now - hwc->freq_time_stamp;
6374 hwc->freq_time_stamp = now;
6376 if (delta > 0 && delta < 2*TICK_NSEC)
6377 perf_adjust_period(event, delta, hwc->last_period, true);
6381 * XXX event_limit might not quite work as expected on inherited
6385 event->pending_kill = POLL_IN;
6386 if (events && atomic_dec_and_test(&event->event_limit)) {
6388 event->pending_kill = POLL_HUP;
6389 event->pending_disable = 1;
6390 irq_work_queue(&event->pending);
6393 if (event->overflow_handler)
6394 event->overflow_handler(event, data, regs);
6396 perf_event_output(event, data, regs);
6398 if (*perf_event_fasync(event) && event->pending_kill) {
6399 event->pending_wakeup = 1;
6400 irq_work_queue(&event->pending);
6406 int perf_event_overflow(struct perf_event *event,
6407 struct perf_sample_data *data,
6408 struct pt_regs *regs)
6410 return __perf_event_overflow(event, 1, data, regs);
6414 * Generic software event infrastructure
6417 struct swevent_htable {
6418 struct swevent_hlist *swevent_hlist;
6419 struct mutex hlist_mutex;
6422 /* Recursion avoidance in each contexts */
6423 int recursion[PERF_NR_CONTEXTS];
6426 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6429 * We directly increment event->count and keep a second value in
6430 * event->hw.period_left to count intervals. This period event
6431 * is kept in the range [-sample_period, 0] so that we can use the
6435 u64 perf_swevent_set_period(struct perf_event *event)
6437 struct hw_perf_event *hwc = &event->hw;
6438 u64 period = hwc->last_period;
6442 hwc->last_period = hwc->sample_period;
6445 old = val = local64_read(&hwc->period_left);
6449 nr = div64_u64(period + val, period);
6450 offset = nr * period;
6452 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6458 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6459 struct perf_sample_data *data,
6460 struct pt_regs *regs)
6462 struct hw_perf_event *hwc = &event->hw;
6466 overflow = perf_swevent_set_period(event);
6468 if (hwc->interrupts == MAX_INTERRUPTS)
6471 for (; overflow; overflow--) {
6472 if (__perf_event_overflow(event, throttle,
6475 * We inhibit the overflow from happening when
6476 * hwc->interrupts == MAX_INTERRUPTS.
6484 static void perf_swevent_event(struct perf_event *event, u64 nr,
6485 struct perf_sample_data *data,
6486 struct pt_regs *regs)
6488 struct hw_perf_event *hwc = &event->hw;
6490 local64_add(nr, &event->count);
6495 if (!is_sampling_event(event))
6498 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6500 return perf_swevent_overflow(event, 1, data, regs);
6502 data->period = event->hw.last_period;
6504 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6505 return perf_swevent_overflow(event, 1, data, regs);
6507 if (local64_add_negative(nr, &hwc->period_left))
6510 perf_swevent_overflow(event, 0, data, regs);
6513 static int perf_exclude_event(struct perf_event *event,
6514 struct pt_regs *regs)
6516 if (event->hw.state & PERF_HES_STOPPED)
6520 if (event->attr.exclude_user && user_mode(regs))
6523 if (event->attr.exclude_kernel && !user_mode(regs))
6530 static int perf_swevent_match(struct perf_event *event,
6531 enum perf_type_id type,
6533 struct perf_sample_data *data,
6534 struct pt_regs *regs)
6536 if (event->attr.type != type)
6539 if (event->attr.config != event_id)
6542 if (perf_exclude_event(event, regs))
6548 static inline u64 swevent_hash(u64 type, u32 event_id)
6550 u64 val = event_id | (type << 32);
6552 return hash_64(val, SWEVENT_HLIST_BITS);
6555 static inline struct hlist_head *
6556 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6558 u64 hash = swevent_hash(type, event_id);
6560 return &hlist->heads[hash];
6563 /* For the read side: events when they trigger */
6564 static inline struct hlist_head *
6565 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6567 struct swevent_hlist *hlist;
6569 hlist = rcu_dereference(swhash->swevent_hlist);
6573 return __find_swevent_head(hlist, type, event_id);
6576 /* For the event head insertion and removal in the hlist */
6577 static inline struct hlist_head *
6578 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6580 struct swevent_hlist *hlist;
6581 u32 event_id = event->attr.config;
6582 u64 type = event->attr.type;
6585 * Event scheduling is always serialized against hlist allocation
6586 * and release. Which makes the protected version suitable here.
6587 * The context lock guarantees that.
6589 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6590 lockdep_is_held(&event->ctx->lock));
6594 return __find_swevent_head(hlist, type, event_id);
6597 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6599 struct perf_sample_data *data,
6600 struct pt_regs *regs)
6602 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6603 struct perf_event *event;
6604 struct hlist_head *head;
6607 head = find_swevent_head_rcu(swhash, type, event_id);
6611 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6612 if (perf_swevent_match(event, type, event_id, data, regs))
6613 perf_swevent_event(event, nr, data, regs);
6619 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6621 int perf_swevent_get_recursion_context(void)
6623 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6625 return get_recursion_context(swhash->recursion);
6627 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6629 inline void perf_swevent_put_recursion_context(int rctx)
6631 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6633 put_recursion_context(swhash->recursion, rctx);
6636 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6638 struct perf_sample_data data;
6640 if (WARN_ON_ONCE(!regs))
6643 perf_sample_data_init(&data, addr, 0);
6644 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6647 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6651 preempt_disable_notrace();
6652 rctx = perf_swevent_get_recursion_context();
6653 if (unlikely(rctx < 0))
6656 ___perf_sw_event(event_id, nr, regs, addr);
6658 perf_swevent_put_recursion_context(rctx);
6660 preempt_enable_notrace();
6663 static void perf_swevent_read(struct perf_event *event)
6667 static int perf_swevent_add(struct perf_event *event, int flags)
6669 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6670 struct hw_perf_event *hwc = &event->hw;
6671 struct hlist_head *head;
6673 if (is_sampling_event(event)) {
6674 hwc->last_period = hwc->sample_period;
6675 perf_swevent_set_period(event);
6678 hwc->state = !(flags & PERF_EF_START);
6680 head = find_swevent_head(swhash, event);
6681 if (WARN_ON_ONCE(!head))
6684 hlist_add_head_rcu(&event->hlist_entry, head);
6685 perf_event_update_userpage(event);
6690 static void perf_swevent_del(struct perf_event *event, int flags)
6692 hlist_del_rcu(&event->hlist_entry);
6695 static void perf_swevent_start(struct perf_event *event, int flags)
6697 event->hw.state = 0;
6700 static void perf_swevent_stop(struct perf_event *event, int flags)
6702 event->hw.state = PERF_HES_STOPPED;
6705 /* Deref the hlist from the update side */
6706 static inline struct swevent_hlist *
6707 swevent_hlist_deref(struct swevent_htable *swhash)
6709 return rcu_dereference_protected(swhash->swevent_hlist,
6710 lockdep_is_held(&swhash->hlist_mutex));
6713 static void swevent_hlist_release(struct swevent_htable *swhash)
6715 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6720 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6721 kfree_rcu(hlist, rcu_head);
6724 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6726 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6728 mutex_lock(&swhash->hlist_mutex);
6730 if (!--swhash->hlist_refcount)
6731 swevent_hlist_release(swhash);
6733 mutex_unlock(&swhash->hlist_mutex);
6736 static void swevent_hlist_put(struct perf_event *event)
6740 for_each_possible_cpu(cpu)
6741 swevent_hlist_put_cpu(event, cpu);
6744 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6746 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6749 mutex_lock(&swhash->hlist_mutex);
6750 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6751 struct swevent_hlist *hlist;
6753 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6758 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6760 swhash->hlist_refcount++;
6762 mutex_unlock(&swhash->hlist_mutex);
6767 static int swevent_hlist_get(struct perf_event *event)
6770 int cpu, failed_cpu;
6773 for_each_possible_cpu(cpu) {
6774 err = swevent_hlist_get_cpu(event, cpu);
6784 for_each_possible_cpu(cpu) {
6785 if (cpu == failed_cpu)
6787 swevent_hlist_put_cpu(event, cpu);
6794 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6796 static void sw_perf_event_destroy(struct perf_event *event)
6798 u64 event_id = event->attr.config;
6800 WARN_ON(event->parent);
6802 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6803 swevent_hlist_put(event);
6806 static int perf_swevent_init(struct perf_event *event)
6808 u64 event_id = event->attr.config;
6810 if (event->attr.type != PERF_TYPE_SOFTWARE)
6814 * no branch sampling for software events
6816 if (has_branch_stack(event))
6820 case PERF_COUNT_SW_CPU_CLOCK:
6821 case PERF_COUNT_SW_TASK_CLOCK:
6828 if (event_id >= PERF_COUNT_SW_MAX)
6831 if (!event->parent) {
6834 err = swevent_hlist_get(event);
6838 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6839 event->destroy = sw_perf_event_destroy;
6845 static struct pmu perf_swevent = {
6846 .task_ctx_nr = perf_sw_context,
6848 .capabilities = PERF_PMU_CAP_NO_NMI,
6850 .event_init = perf_swevent_init,
6851 .add = perf_swevent_add,
6852 .del = perf_swevent_del,
6853 .start = perf_swevent_start,
6854 .stop = perf_swevent_stop,
6855 .read = perf_swevent_read,
6858 #ifdef CONFIG_EVENT_TRACING
6860 static int perf_tp_filter_match(struct perf_event *event,
6861 struct perf_sample_data *data)
6863 void *record = data->raw->data;
6865 /* only top level events have filters set */
6867 event = event->parent;
6869 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6874 static int perf_tp_event_match(struct perf_event *event,
6875 struct perf_sample_data *data,
6876 struct pt_regs *regs)
6878 if (event->hw.state & PERF_HES_STOPPED)
6881 * All tracepoints are from kernel-space.
6883 if (event->attr.exclude_kernel)
6886 if (!perf_tp_filter_match(event, data))
6892 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6893 struct pt_regs *regs, struct hlist_head *head, int rctx,
6894 struct task_struct *task)
6896 struct perf_sample_data data;
6897 struct perf_event *event;
6899 struct perf_raw_record raw = {
6904 perf_sample_data_init(&data, addr, 0);
6907 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6908 if (perf_tp_event_match(event, &data, regs))
6909 perf_swevent_event(event, count, &data, regs);
6913 * If we got specified a target task, also iterate its context and
6914 * deliver this event there too.
6916 if (task && task != current) {
6917 struct perf_event_context *ctx;
6918 struct trace_entry *entry = record;
6921 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6925 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6926 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6928 if (event->attr.config != entry->type)
6930 if (perf_tp_event_match(event, &data, regs))
6931 perf_swevent_event(event, count, &data, regs);
6937 perf_swevent_put_recursion_context(rctx);
6939 EXPORT_SYMBOL_GPL(perf_tp_event);
6941 static void tp_perf_event_destroy(struct perf_event *event)
6943 perf_trace_destroy(event);
6946 static int perf_tp_event_init(struct perf_event *event)
6950 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6954 * no branch sampling for tracepoint events
6956 if (has_branch_stack(event))
6959 err = perf_trace_init(event);
6963 event->destroy = tp_perf_event_destroy;
6968 static struct pmu perf_tracepoint = {
6969 .task_ctx_nr = perf_sw_context,
6971 .event_init = perf_tp_event_init,
6972 .add = perf_trace_add,
6973 .del = perf_trace_del,
6974 .start = perf_swevent_start,
6975 .stop = perf_swevent_stop,
6976 .read = perf_swevent_read,
6979 static inline void perf_tp_register(void)
6981 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6984 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6989 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6992 filter_str = strndup_user(arg, PAGE_SIZE);
6993 if (IS_ERR(filter_str))
6994 return PTR_ERR(filter_str);
6996 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7002 static void perf_event_free_filter(struct perf_event *event)
7004 ftrace_profile_free_filter(event);
7007 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7009 struct bpf_prog *prog;
7011 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7014 if (event->tp_event->prog)
7017 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7018 /* bpf programs can only be attached to u/kprobes */
7021 prog = bpf_prog_get(prog_fd);
7023 return PTR_ERR(prog);
7025 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7026 /* valid fd, but invalid bpf program type */
7031 event->tp_event->prog = prog;
7036 static void perf_event_free_bpf_prog(struct perf_event *event)
7038 struct bpf_prog *prog;
7040 if (!event->tp_event)
7043 prog = event->tp_event->prog;
7045 event->tp_event->prog = NULL;
7052 static inline void perf_tp_register(void)
7056 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7061 static void perf_event_free_filter(struct perf_event *event)
7065 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7070 static void perf_event_free_bpf_prog(struct perf_event *event)
7073 #endif /* CONFIG_EVENT_TRACING */
7075 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7076 void perf_bp_event(struct perf_event *bp, void *data)
7078 struct perf_sample_data sample;
7079 struct pt_regs *regs = data;
7081 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7083 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7084 perf_swevent_event(bp, 1, &sample, regs);
7089 * hrtimer based swevent callback
7092 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7094 enum hrtimer_restart ret = HRTIMER_RESTART;
7095 struct perf_sample_data data;
7096 struct pt_regs *regs;
7097 struct perf_event *event;
7100 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7102 if (event->state != PERF_EVENT_STATE_ACTIVE)
7103 return HRTIMER_NORESTART;
7105 event->pmu->read(event);
7107 perf_sample_data_init(&data, 0, event->hw.last_period);
7108 regs = get_irq_regs();
7110 if (regs && !perf_exclude_event(event, regs)) {
7111 if (!(event->attr.exclude_idle && is_idle_task(current)))
7112 if (__perf_event_overflow(event, 1, &data, regs))
7113 ret = HRTIMER_NORESTART;
7116 period = max_t(u64, 10000, event->hw.sample_period);
7117 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7122 static void perf_swevent_start_hrtimer(struct perf_event *event)
7124 struct hw_perf_event *hwc = &event->hw;
7127 if (!is_sampling_event(event))
7130 period = local64_read(&hwc->period_left);
7135 local64_set(&hwc->period_left, 0);
7137 period = max_t(u64, 10000, hwc->sample_period);
7139 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7140 HRTIMER_MODE_REL_PINNED);
7143 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7145 struct hw_perf_event *hwc = &event->hw;
7147 if (is_sampling_event(event)) {
7148 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7149 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7151 hrtimer_cancel(&hwc->hrtimer);
7155 static void perf_swevent_init_hrtimer(struct perf_event *event)
7157 struct hw_perf_event *hwc = &event->hw;
7159 if (!is_sampling_event(event))
7162 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7163 hwc->hrtimer.function = perf_swevent_hrtimer;
7166 * Since hrtimers have a fixed rate, we can do a static freq->period
7167 * mapping and avoid the whole period adjust feedback stuff.
7169 if (event->attr.freq) {
7170 long freq = event->attr.sample_freq;
7172 event->attr.sample_period = NSEC_PER_SEC / freq;
7173 hwc->sample_period = event->attr.sample_period;
7174 local64_set(&hwc->period_left, hwc->sample_period);
7175 hwc->last_period = hwc->sample_period;
7176 event->attr.freq = 0;
7181 * Software event: cpu wall time clock
7184 static void cpu_clock_event_update(struct perf_event *event)
7189 now = local_clock();
7190 prev = local64_xchg(&event->hw.prev_count, now);
7191 local64_add(now - prev, &event->count);
7194 static void cpu_clock_event_start(struct perf_event *event, int flags)
7196 local64_set(&event->hw.prev_count, local_clock());
7197 perf_swevent_start_hrtimer(event);
7200 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7202 perf_swevent_cancel_hrtimer(event);
7203 cpu_clock_event_update(event);
7206 static int cpu_clock_event_add(struct perf_event *event, int flags)
7208 if (flags & PERF_EF_START)
7209 cpu_clock_event_start(event, flags);
7210 perf_event_update_userpage(event);
7215 static void cpu_clock_event_del(struct perf_event *event, int flags)
7217 cpu_clock_event_stop(event, flags);
7220 static void cpu_clock_event_read(struct perf_event *event)
7222 cpu_clock_event_update(event);
7225 static int cpu_clock_event_init(struct perf_event *event)
7227 if (event->attr.type != PERF_TYPE_SOFTWARE)
7230 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7234 * no branch sampling for software events
7236 if (has_branch_stack(event))
7239 perf_swevent_init_hrtimer(event);
7244 static struct pmu perf_cpu_clock = {
7245 .task_ctx_nr = perf_sw_context,
7247 .capabilities = PERF_PMU_CAP_NO_NMI,
7249 .event_init = cpu_clock_event_init,
7250 .add = cpu_clock_event_add,
7251 .del = cpu_clock_event_del,
7252 .start = cpu_clock_event_start,
7253 .stop = cpu_clock_event_stop,
7254 .read = cpu_clock_event_read,
7258 * Software event: task time clock
7261 static void task_clock_event_update(struct perf_event *event, u64 now)
7266 prev = local64_xchg(&event->hw.prev_count, now);
7268 local64_add(delta, &event->count);
7271 static void task_clock_event_start(struct perf_event *event, int flags)
7273 local64_set(&event->hw.prev_count, event->ctx->time);
7274 perf_swevent_start_hrtimer(event);
7277 static void task_clock_event_stop(struct perf_event *event, int flags)
7279 perf_swevent_cancel_hrtimer(event);
7280 task_clock_event_update(event, event->ctx->time);
7283 static int task_clock_event_add(struct perf_event *event, int flags)
7285 if (flags & PERF_EF_START)
7286 task_clock_event_start(event, flags);
7287 perf_event_update_userpage(event);
7292 static void task_clock_event_del(struct perf_event *event, int flags)
7294 task_clock_event_stop(event, PERF_EF_UPDATE);
7297 static void task_clock_event_read(struct perf_event *event)
7299 u64 now = perf_clock();
7300 u64 delta = now - event->ctx->timestamp;
7301 u64 time = event->ctx->time + delta;
7303 task_clock_event_update(event, time);
7306 static int task_clock_event_init(struct perf_event *event)
7308 if (event->attr.type != PERF_TYPE_SOFTWARE)
7311 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7315 * no branch sampling for software events
7317 if (has_branch_stack(event))
7320 perf_swevent_init_hrtimer(event);
7325 static struct pmu perf_task_clock = {
7326 .task_ctx_nr = perf_sw_context,
7328 .capabilities = PERF_PMU_CAP_NO_NMI,
7330 .event_init = task_clock_event_init,
7331 .add = task_clock_event_add,
7332 .del = task_clock_event_del,
7333 .start = task_clock_event_start,
7334 .stop = task_clock_event_stop,
7335 .read = task_clock_event_read,
7338 static void perf_pmu_nop_void(struct pmu *pmu)
7342 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7346 static int perf_pmu_nop_int(struct pmu *pmu)
7351 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7353 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7355 __this_cpu_write(nop_txn_flags, flags);
7357 if (flags & ~PERF_PMU_TXN_ADD)
7360 perf_pmu_disable(pmu);
7363 static int perf_pmu_commit_txn(struct pmu *pmu)
7365 unsigned int flags = __this_cpu_read(nop_txn_flags);
7367 __this_cpu_write(nop_txn_flags, 0);
7369 if (flags & ~PERF_PMU_TXN_ADD)
7372 perf_pmu_enable(pmu);
7376 static void perf_pmu_cancel_txn(struct pmu *pmu)
7378 unsigned int flags = __this_cpu_read(nop_txn_flags);
7380 __this_cpu_write(nop_txn_flags, 0);
7382 if (flags & ~PERF_PMU_TXN_ADD)
7385 perf_pmu_enable(pmu);
7388 static int perf_event_idx_default(struct perf_event *event)
7394 * Ensures all contexts with the same task_ctx_nr have the same
7395 * pmu_cpu_context too.
7397 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7404 list_for_each_entry(pmu, &pmus, entry) {
7405 if (pmu->task_ctx_nr == ctxn)
7406 return pmu->pmu_cpu_context;
7412 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7416 for_each_possible_cpu(cpu) {
7417 struct perf_cpu_context *cpuctx;
7419 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7421 if (cpuctx->unique_pmu == old_pmu)
7422 cpuctx->unique_pmu = pmu;
7426 static void free_pmu_context(struct pmu *pmu)
7430 mutex_lock(&pmus_lock);
7432 * Like a real lame refcount.
7434 list_for_each_entry(i, &pmus, entry) {
7435 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7436 update_pmu_context(i, pmu);
7441 free_percpu(pmu->pmu_cpu_context);
7443 mutex_unlock(&pmus_lock);
7445 static struct idr pmu_idr;
7448 type_show(struct device *dev, struct device_attribute *attr, char *page)
7450 struct pmu *pmu = dev_get_drvdata(dev);
7452 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7454 static DEVICE_ATTR_RO(type);
7457 perf_event_mux_interval_ms_show(struct device *dev,
7458 struct device_attribute *attr,
7461 struct pmu *pmu = dev_get_drvdata(dev);
7463 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7466 static DEFINE_MUTEX(mux_interval_mutex);
7469 perf_event_mux_interval_ms_store(struct device *dev,
7470 struct device_attribute *attr,
7471 const char *buf, size_t count)
7473 struct pmu *pmu = dev_get_drvdata(dev);
7474 int timer, cpu, ret;
7476 ret = kstrtoint(buf, 0, &timer);
7483 /* same value, noting to do */
7484 if (timer == pmu->hrtimer_interval_ms)
7487 mutex_lock(&mux_interval_mutex);
7488 pmu->hrtimer_interval_ms = timer;
7490 /* update all cpuctx for this PMU */
7492 for_each_online_cpu(cpu) {
7493 struct perf_cpu_context *cpuctx;
7494 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7495 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7497 cpu_function_call(cpu,
7498 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7501 mutex_unlock(&mux_interval_mutex);
7505 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7507 static struct attribute *pmu_dev_attrs[] = {
7508 &dev_attr_type.attr,
7509 &dev_attr_perf_event_mux_interval_ms.attr,
7512 ATTRIBUTE_GROUPS(pmu_dev);
7514 static int pmu_bus_running;
7515 static struct bus_type pmu_bus = {
7516 .name = "event_source",
7517 .dev_groups = pmu_dev_groups,
7520 static void pmu_dev_release(struct device *dev)
7525 static int pmu_dev_alloc(struct pmu *pmu)
7529 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7533 pmu->dev->groups = pmu->attr_groups;
7534 device_initialize(pmu->dev);
7535 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7539 dev_set_drvdata(pmu->dev, pmu);
7540 pmu->dev->bus = &pmu_bus;
7541 pmu->dev->release = pmu_dev_release;
7542 ret = device_add(pmu->dev);
7550 put_device(pmu->dev);
7554 static struct lock_class_key cpuctx_mutex;
7555 static struct lock_class_key cpuctx_lock;
7557 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7561 mutex_lock(&pmus_lock);
7563 pmu->pmu_disable_count = alloc_percpu(int);
7564 if (!pmu->pmu_disable_count)
7573 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7581 if (pmu_bus_running) {
7582 ret = pmu_dev_alloc(pmu);
7588 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7589 if (pmu->pmu_cpu_context)
7590 goto got_cpu_context;
7593 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7594 if (!pmu->pmu_cpu_context)
7597 for_each_possible_cpu(cpu) {
7598 struct perf_cpu_context *cpuctx;
7600 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7601 __perf_event_init_context(&cpuctx->ctx);
7602 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7603 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7604 cpuctx->ctx.pmu = pmu;
7606 __perf_mux_hrtimer_init(cpuctx, cpu);
7608 cpuctx->unique_pmu = pmu;
7612 if (!pmu->start_txn) {
7613 if (pmu->pmu_enable) {
7615 * If we have pmu_enable/pmu_disable calls, install
7616 * transaction stubs that use that to try and batch
7617 * hardware accesses.
7619 pmu->start_txn = perf_pmu_start_txn;
7620 pmu->commit_txn = perf_pmu_commit_txn;
7621 pmu->cancel_txn = perf_pmu_cancel_txn;
7623 pmu->start_txn = perf_pmu_nop_txn;
7624 pmu->commit_txn = perf_pmu_nop_int;
7625 pmu->cancel_txn = perf_pmu_nop_void;
7629 if (!pmu->pmu_enable) {
7630 pmu->pmu_enable = perf_pmu_nop_void;
7631 pmu->pmu_disable = perf_pmu_nop_void;
7634 if (!pmu->event_idx)
7635 pmu->event_idx = perf_event_idx_default;
7637 list_add_rcu(&pmu->entry, &pmus);
7638 atomic_set(&pmu->exclusive_cnt, 0);
7641 mutex_unlock(&pmus_lock);
7646 device_del(pmu->dev);
7647 put_device(pmu->dev);
7650 if (pmu->type >= PERF_TYPE_MAX)
7651 idr_remove(&pmu_idr, pmu->type);
7654 free_percpu(pmu->pmu_disable_count);
7657 EXPORT_SYMBOL_GPL(perf_pmu_register);
7659 void perf_pmu_unregister(struct pmu *pmu)
7661 mutex_lock(&pmus_lock);
7662 list_del_rcu(&pmu->entry);
7663 mutex_unlock(&pmus_lock);
7666 * We dereference the pmu list under both SRCU and regular RCU, so
7667 * synchronize against both of those.
7669 synchronize_srcu(&pmus_srcu);
7672 free_percpu(pmu->pmu_disable_count);
7673 if (pmu->type >= PERF_TYPE_MAX)
7674 idr_remove(&pmu_idr, pmu->type);
7675 device_del(pmu->dev);
7676 put_device(pmu->dev);
7677 free_pmu_context(pmu);
7679 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7681 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7683 struct perf_event_context *ctx = NULL;
7686 if (!try_module_get(pmu->module))
7689 if (event->group_leader != event) {
7691 * This ctx->mutex can nest when we're called through
7692 * inheritance. See the perf_event_ctx_lock_nested() comment.
7694 ctx = perf_event_ctx_lock_nested(event->group_leader,
7695 SINGLE_DEPTH_NESTING);
7700 ret = pmu->event_init(event);
7703 perf_event_ctx_unlock(event->group_leader, ctx);
7706 module_put(pmu->module);
7711 static struct pmu *perf_init_event(struct perf_event *event)
7713 struct pmu *pmu = NULL;
7717 idx = srcu_read_lock(&pmus_srcu);
7720 pmu = idr_find(&pmu_idr, event->attr.type);
7723 ret = perf_try_init_event(pmu, event);
7729 list_for_each_entry_rcu(pmu, &pmus, entry) {
7730 ret = perf_try_init_event(pmu, event);
7734 if (ret != -ENOENT) {
7739 pmu = ERR_PTR(-ENOENT);
7741 srcu_read_unlock(&pmus_srcu, idx);
7746 static void account_event_cpu(struct perf_event *event, int cpu)
7751 if (is_cgroup_event(event))
7752 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7755 static void account_event(struct perf_event *event)
7762 if (event->attach_state & PERF_ATTACH_TASK)
7764 if (event->attr.mmap || event->attr.mmap_data)
7765 atomic_inc(&nr_mmap_events);
7766 if (event->attr.comm)
7767 atomic_inc(&nr_comm_events);
7768 if (event->attr.task)
7769 atomic_inc(&nr_task_events);
7770 if (event->attr.freq) {
7771 if (atomic_inc_return(&nr_freq_events) == 1)
7772 tick_nohz_full_kick_all();
7774 if (event->attr.context_switch) {
7775 atomic_inc(&nr_switch_events);
7778 if (has_branch_stack(event))
7780 if (is_cgroup_event(event))
7784 static_key_slow_inc(&perf_sched_events.key);
7786 account_event_cpu(event, event->cpu);
7790 * Allocate and initialize a event structure
7792 static struct perf_event *
7793 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7794 struct task_struct *task,
7795 struct perf_event *group_leader,
7796 struct perf_event *parent_event,
7797 perf_overflow_handler_t overflow_handler,
7798 void *context, int cgroup_fd)
7801 struct perf_event *event;
7802 struct hw_perf_event *hwc;
7805 if ((unsigned)cpu >= nr_cpu_ids) {
7806 if (!task || cpu != -1)
7807 return ERR_PTR(-EINVAL);
7810 event = kzalloc(sizeof(*event), GFP_KERNEL);
7812 return ERR_PTR(-ENOMEM);
7815 * Single events are their own group leaders, with an
7816 * empty sibling list:
7819 group_leader = event;
7821 mutex_init(&event->child_mutex);
7822 INIT_LIST_HEAD(&event->child_list);
7824 INIT_LIST_HEAD(&event->group_entry);
7825 INIT_LIST_HEAD(&event->event_entry);
7826 INIT_LIST_HEAD(&event->sibling_list);
7827 INIT_LIST_HEAD(&event->rb_entry);
7828 INIT_LIST_HEAD(&event->active_entry);
7829 INIT_HLIST_NODE(&event->hlist_entry);
7832 init_waitqueue_head(&event->waitq);
7833 init_irq_work(&event->pending, perf_pending_event);
7835 mutex_init(&event->mmap_mutex);
7837 atomic_long_set(&event->refcount, 1);
7839 event->attr = *attr;
7840 event->group_leader = group_leader;
7844 event->parent = parent_event;
7846 event->ns = get_pid_ns(task_active_pid_ns(current));
7847 event->id = atomic64_inc_return(&perf_event_id);
7849 event->state = PERF_EVENT_STATE_INACTIVE;
7852 event->attach_state = PERF_ATTACH_TASK;
7854 * XXX pmu::event_init needs to know what task to account to
7855 * and we cannot use the ctx information because we need the
7856 * pmu before we get a ctx.
7858 event->hw.target = task;
7861 event->clock = &local_clock;
7863 event->clock = parent_event->clock;
7865 if (!overflow_handler && parent_event) {
7866 overflow_handler = parent_event->overflow_handler;
7867 context = parent_event->overflow_handler_context;
7870 event->overflow_handler = overflow_handler;
7871 event->overflow_handler_context = context;
7873 perf_event__state_init(event);
7878 hwc->sample_period = attr->sample_period;
7879 if (attr->freq && attr->sample_freq)
7880 hwc->sample_period = 1;
7881 hwc->last_period = hwc->sample_period;
7883 local64_set(&hwc->period_left, hwc->sample_period);
7886 * we currently do not support PERF_FORMAT_GROUP on inherited events
7888 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7891 if (!has_branch_stack(event))
7892 event->attr.branch_sample_type = 0;
7894 if (cgroup_fd != -1) {
7895 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7900 pmu = perf_init_event(event);
7903 else if (IS_ERR(pmu)) {
7908 err = exclusive_event_init(event);
7912 if (!event->parent) {
7913 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7914 err = get_callchain_buffers();
7923 exclusive_event_destroy(event);
7927 event->destroy(event);
7928 module_put(pmu->module);
7930 if (is_cgroup_event(event))
7931 perf_detach_cgroup(event);
7933 put_pid_ns(event->ns);
7936 return ERR_PTR(err);
7939 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7940 struct perf_event_attr *attr)
7945 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7949 * zero the full structure, so that a short copy will be nice.
7951 memset(attr, 0, sizeof(*attr));
7953 ret = get_user(size, &uattr->size);
7957 if (size > PAGE_SIZE) /* silly large */
7960 if (!size) /* abi compat */
7961 size = PERF_ATTR_SIZE_VER0;
7963 if (size < PERF_ATTR_SIZE_VER0)
7967 * If we're handed a bigger struct than we know of,
7968 * ensure all the unknown bits are 0 - i.e. new
7969 * user-space does not rely on any kernel feature
7970 * extensions we dont know about yet.
7972 if (size > sizeof(*attr)) {
7973 unsigned char __user *addr;
7974 unsigned char __user *end;
7977 addr = (void __user *)uattr + sizeof(*attr);
7978 end = (void __user *)uattr + size;
7980 for (; addr < end; addr++) {
7981 ret = get_user(val, addr);
7987 size = sizeof(*attr);
7990 ret = copy_from_user(attr, uattr, size);
7994 if (attr->__reserved_1)
7997 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8000 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8003 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8004 u64 mask = attr->branch_sample_type;
8006 /* only using defined bits */
8007 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8010 /* at least one branch bit must be set */
8011 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8014 /* propagate priv level, when not set for branch */
8015 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8017 /* exclude_kernel checked on syscall entry */
8018 if (!attr->exclude_kernel)
8019 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8021 if (!attr->exclude_user)
8022 mask |= PERF_SAMPLE_BRANCH_USER;
8024 if (!attr->exclude_hv)
8025 mask |= PERF_SAMPLE_BRANCH_HV;
8027 * adjust user setting (for HW filter setup)
8029 attr->branch_sample_type = mask;
8031 /* privileged levels capture (kernel, hv): check permissions */
8032 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8033 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8037 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8038 ret = perf_reg_validate(attr->sample_regs_user);
8043 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8044 if (!arch_perf_have_user_stack_dump())
8048 * We have __u32 type for the size, but so far
8049 * we can only use __u16 as maximum due to the
8050 * __u16 sample size limit.
8052 if (attr->sample_stack_user >= USHRT_MAX)
8054 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8058 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8059 ret = perf_reg_validate(attr->sample_regs_intr);
8064 put_user(sizeof(*attr), &uattr->size);
8070 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8072 struct ring_buffer *rb = NULL;
8078 /* don't allow circular references */
8079 if (event == output_event)
8083 * Don't allow cross-cpu buffers
8085 if (output_event->cpu != event->cpu)
8089 * If its not a per-cpu rb, it must be the same task.
8091 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8095 * Mixing clocks in the same buffer is trouble you don't need.
8097 if (output_event->clock != event->clock)
8101 * If both events generate aux data, they must be on the same PMU
8103 if (has_aux(event) && has_aux(output_event) &&
8104 event->pmu != output_event->pmu)
8108 mutex_lock(&event->mmap_mutex);
8109 /* Can't redirect output if we've got an active mmap() */
8110 if (atomic_read(&event->mmap_count))
8114 /* get the rb we want to redirect to */
8115 rb = ring_buffer_get(output_event);
8120 ring_buffer_attach(event, rb);
8124 mutex_unlock(&event->mmap_mutex);
8130 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8136 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8139 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8141 bool nmi_safe = false;
8144 case CLOCK_MONOTONIC:
8145 event->clock = &ktime_get_mono_fast_ns;
8149 case CLOCK_MONOTONIC_RAW:
8150 event->clock = &ktime_get_raw_fast_ns;
8154 case CLOCK_REALTIME:
8155 event->clock = &ktime_get_real_ns;
8158 case CLOCK_BOOTTIME:
8159 event->clock = &ktime_get_boot_ns;
8163 event->clock = &ktime_get_tai_ns;
8170 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8177 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8179 * @attr_uptr: event_id type attributes for monitoring/sampling
8182 * @group_fd: group leader event fd
8184 SYSCALL_DEFINE5(perf_event_open,
8185 struct perf_event_attr __user *, attr_uptr,
8186 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8188 struct perf_event *group_leader = NULL, *output_event = NULL;
8189 struct perf_event *event, *sibling;
8190 struct perf_event_attr attr;
8191 struct perf_event_context *ctx, *uninitialized_var(gctx);
8192 struct file *event_file = NULL;
8193 struct fd group = {NULL, 0};
8194 struct task_struct *task = NULL;
8199 int f_flags = O_RDWR;
8202 /* for future expandability... */
8203 if (flags & ~PERF_FLAG_ALL)
8206 err = perf_copy_attr(attr_uptr, &attr);
8210 if (!attr.exclude_kernel) {
8211 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8216 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8219 if (attr.sample_period & (1ULL << 63))
8224 * In cgroup mode, the pid argument is used to pass the fd
8225 * opened to the cgroup directory in cgroupfs. The cpu argument
8226 * designates the cpu on which to monitor threads from that
8229 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8232 if (flags & PERF_FLAG_FD_CLOEXEC)
8233 f_flags |= O_CLOEXEC;
8235 event_fd = get_unused_fd_flags(f_flags);
8239 if (group_fd != -1) {
8240 err = perf_fget_light(group_fd, &group);
8243 group_leader = group.file->private_data;
8244 if (flags & PERF_FLAG_FD_OUTPUT)
8245 output_event = group_leader;
8246 if (flags & PERF_FLAG_FD_NO_GROUP)
8247 group_leader = NULL;
8250 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8251 task = find_lively_task_by_vpid(pid);
8253 err = PTR_ERR(task);
8258 if (task && group_leader &&
8259 group_leader->attr.inherit != attr.inherit) {
8266 if (flags & PERF_FLAG_PID_CGROUP)
8269 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8270 NULL, NULL, cgroup_fd);
8271 if (IS_ERR(event)) {
8272 err = PTR_ERR(event);
8276 if (is_sampling_event(event)) {
8277 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8283 account_event(event);
8286 * Special case software events and allow them to be part of
8287 * any hardware group.
8291 if (attr.use_clockid) {
8292 err = perf_event_set_clock(event, attr.clockid);
8298 (is_software_event(event) != is_software_event(group_leader))) {
8299 if (is_software_event(event)) {
8301 * If event and group_leader are not both a software
8302 * event, and event is, then group leader is not.
8304 * Allow the addition of software events to !software
8305 * groups, this is safe because software events never
8308 pmu = group_leader->pmu;
8309 } else if (is_software_event(group_leader) &&
8310 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8312 * In case the group is a pure software group, and we
8313 * try to add a hardware event, move the whole group to
8314 * the hardware context.
8321 * Get the target context (task or percpu):
8323 ctx = find_get_context(pmu, task, event);
8329 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8335 put_task_struct(task);
8340 * Look up the group leader (we will attach this event to it):
8346 * Do not allow a recursive hierarchy (this new sibling
8347 * becoming part of another group-sibling):
8349 if (group_leader->group_leader != group_leader)
8352 /* All events in a group should have the same clock */
8353 if (group_leader->clock != event->clock)
8357 * Do not allow to attach to a group in a different
8358 * task or CPU context:
8362 * Make sure we're both on the same task, or both
8365 if (group_leader->ctx->task != ctx->task)
8369 * Make sure we're both events for the same CPU;
8370 * grouping events for different CPUs is broken; since
8371 * you can never concurrently schedule them anyhow.
8373 if (group_leader->cpu != event->cpu)
8376 if (group_leader->ctx != ctx)
8381 * Only a group leader can be exclusive or pinned
8383 if (attr.exclusive || attr.pinned)
8388 err = perf_event_set_output(event, output_event);
8393 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8395 if (IS_ERR(event_file)) {
8396 err = PTR_ERR(event_file);
8401 gctx = group_leader->ctx;
8402 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8403 if (gctx->task == TASK_TOMBSTONE) {
8408 mutex_lock(&ctx->mutex);
8411 if (ctx->task == TASK_TOMBSTONE) {
8416 if (!perf_event_validate_size(event)) {
8422 * Must be under the same ctx::mutex as perf_install_in_context(),
8423 * because we need to serialize with concurrent event creation.
8425 if (!exclusive_event_installable(event, ctx)) {
8426 /* exclusive and group stuff are assumed mutually exclusive */
8427 WARN_ON_ONCE(move_group);
8433 WARN_ON_ONCE(ctx->parent_ctx);
8437 * See perf_event_ctx_lock() for comments on the details
8438 * of swizzling perf_event::ctx.
8440 perf_remove_from_context(group_leader, 0);
8442 list_for_each_entry(sibling, &group_leader->sibling_list,
8444 perf_remove_from_context(sibling, 0);
8449 * Wait for everybody to stop referencing the events through
8450 * the old lists, before installing it on new lists.
8455 * Install the group siblings before the group leader.
8457 * Because a group leader will try and install the entire group
8458 * (through the sibling list, which is still in-tact), we can
8459 * end up with siblings installed in the wrong context.
8461 * By installing siblings first we NO-OP because they're not
8462 * reachable through the group lists.
8464 list_for_each_entry(sibling, &group_leader->sibling_list,
8466 perf_event__state_init(sibling);
8467 perf_install_in_context(ctx, sibling, sibling->cpu);
8472 * Removing from the context ends up with disabled
8473 * event. What we want here is event in the initial
8474 * startup state, ready to be add into new context.
8476 perf_event__state_init(group_leader);
8477 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8481 * Now that all events are installed in @ctx, nothing
8482 * references @gctx anymore, so drop the last reference we have
8489 * Precalculate sample_data sizes; do while holding ctx::mutex such
8490 * that we're serialized against further additions and before
8491 * perf_install_in_context() which is the point the event is active and
8492 * can use these values.
8494 perf_event__header_size(event);
8495 perf_event__id_header_size(event);
8497 event->owner = current;
8499 perf_install_in_context(ctx, event, event->cpu);
8500 perf_unpin_context(ctx);
8503 mutex_unlock(&gctx->mutex);
8504 mutex_unlock(&ctx->mutex);
8508 mutex_lock(¤t->perf_event_mutex);
8509 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8510 mutex_unlock(¤t->perf_event_mutex);
8513 * Drop the reference on the group_event after placing the
8514 * new event on the sibling_list. This ensures destruction
8515 * of the group leader will find the pointer to itself in
8516 * perf_group_detach().
8519 fd_install(event_fd, event_file);
8524 mutex_unlock(&gctx->mutex);
8525 mutex_unlock(&ctx->mutex);
8529 perf_unpin_context(ctx);
8533 * If event_file is set, the fput() above will have called ->release()
8534 * and that will take care of freeing the event.
8542 put_task_struct(task);
8546 put_unused_fd(event_fd);
8551 * perf_event_create_kernel_counter
8553 * @attr: attributes of the counter to create
8554 * @cpu: cpu in which the counter is bound
8555 * @task: task to profile (NULL for percpu)
8558 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8559 struct task_struct *task,
8560 perf_overflow_handler_t overflow_handler,
8563 struct perf_event_context *ctx;
8564 struct perf_event *event;
8568 * Get the target context (task or percpu):
8571 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8572 overflow_handler, context, -1);
8573 if (IS_ERR(event)) {
8574 err = PTR_ERR(event);
8578 /* Mark owner so we could distinguish it from user events. */
8579 event->owner = TASK_TOMBSTONE;
8581 account_event(event);
8583 ctx = find_get_context(event->pmu, task, event);
8589 WARN_ON_ONCE(ctx->parent_ctx);
8590 mutex_lock(&ctx->mutex);
8591 if (ctx->task == TASK_TOMBSTONE) {
8596 if (!exclusive_event_installable(event, ctx)) {
8601 perf_install_in_context(ctx, event, cpu);
8602 perf_unpin_context(ctx);
8603 mutex_unlock(&ctx->mutex);
8608 mutex_unlock(&ctx->mutex);
8609 perf_unpin_context(ctx);
8614 return ERR_PTR(err);
8616 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8618 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8620 struct perf_event_context *src_ctx;
8621 struct perf_event_context *dst_ctx;
8622 struct perf_event *event, *tmp;
8625 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8626 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8629 * See perf_event_ctx_lock() for comments on the details
8630 * of swizzling perf_event::ctx.
8632 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8633 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8635 perf_remove_from_context(event, 0);
8636 unaccount_event_cpu(event, src_cpu);
8638 list_add(&event->migrate_entry, &events);
8642 * Wait for the events to quiesce before re-instating them.
8647 * Re-instate events in 2 passes.
8649 * Skip over group leaders and only install siblings on this first
8650 * pass, siblings will not get enabled without a leader, however a
8651 * leader will enable its siblings, even if those are still on the old
8654 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8655 if (event->group_leader == event)
8658 list_del(&event->migrate_entry);
8659 if (event->state >= PERF_EVENT_STATE_OFF)
8660 event->state = PERF_EVENT_STATE_INACTIVE;
8661 account_event_cpu(event, dst_cpu);
8662 perf_install_in_context(dst_ctx, event, dst_cpu);
8667 * Once all the siblings are setup properly, install the group leaders
8670 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8671 list_del(&event->migrate_entry);
8672 if (event->state >= PERF_EVENT_STATE_OFF)
8673 event->state = PERF_EVENT_STATE_INACTIVE;
8674 account_event_cpu(event, dst_cpu);
8675 perf_install_in_context(dst_ctx, event, dst_cpu);
8678 mutex_unlock(&dst_ctx->mutex);
8679 mutex_unlock(&src_ctx->mutex);
8681 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8683 static void sync_child_event(struct perf_event *child_event,
8684 struct task_struct *child)
8686 struct perf_event *parent_event = child_event->parent;
8689 if (child_event->attr.inherit_stat)
8690 perf_event_read_event(child_event, child);
8692 child_val = perf_event_count(child_event);
8695 * Add back the child's count to the parent's count:
8697 atomic64_add(child_val, &parent_event->child_count);
8698 atomic64_add(child_event->total_time_enabled,
8699 &parent_event->child_total_time_enabled);
8700 atomic64_add(child_event->total_time_running,
8701 &parent_event->child_total_time_running);
8705 perf_event_exit_event(struct perf_event *child_event,
8706 struct perf_event_context *child_ctx,
8707 struct task_struct *child)
8709 struct perf_event *parent_event = child_event->parent;
8712 * Do not destroy the 'original' grouping; because of the context
8713 * switch optimization the original events could've ended up in a
8714 * random child task.
8716 * If we were to destroy the original group, all group related
8717 * operations would cease to function properly after this random
8720 * Do destroy all inherited groups, we don't care about those
8721 * and being thorough is better.
8723 raw_spin_lock_irq(&child_ctx->lock);
8724 WARN_ON_ONCE(child_ctx->is_active);
8727 perf_group_detach(child_event);
8728 list_del_event(child_event, child_ctx);
8729 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
8730 raw_spin_unlock_irq(&child_ctx->lock);
8733 * Parent events are governed by their filedesc, retain them.
8735 if (!parent_event) {
8736 perf_event_wakeup(child_event);
8740 * Child events can be cleaned up.
8743 sync_child_event(child_event, child);
8746 * Remove this event from the parent's list
8748 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8749 mutex_lock(&parent_event->child_mutex);
8750 list_del_init(&child_event->child_list);
8751 mutex_unlock(&parent_event->child_mutex);
8754 * Kick perf_poll() for is_event_hup().
8756 perf_event_wakeup(parent_event);
8757 free_event(child_event);
8758 put_event(parent_event);
8761 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8763 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8764 struct perf_event *child_event, *next;
8766 WARN_ON_ONCE(child != current);
8768 child_ctx = perf_pin_task_context(child, ctxn);
8773 * In order to reduce the amount of tricky in ctx tear-down, we hold
8774 * ctx::mutex over the entire thing. This serializes against almost
8775 * everything that wants to access the ctx.
8777 * The exception is sys_perf_event_open() /
8778 * perf_event_create_kernel_count() which does find_get_context()
8779 * without ctx::mutex (it cannot because of the move_group double mutex
8780 * lock thing). See the comments in perf_install_in_context().
8782 mutex_lock(&child_ctx->mutex);
8785 * In a single ctx::lock section, de-schedule the events and detach the
8786 * context from the task such that we cannot ever get it scheduled back
8789 raw_spin_lock_irq(&child_ctx->lock);
8790 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8793 * Now that the context is inactive, destroy the task <-> ctx relation
8794 * and mark the context dead.
8796 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8797 put_ctx(child_ctx); /* cannot be last */
8798 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8799 put_task_struct(current); /* cannot be last */
8801 clone_ctx = unclone_ctx(child_ctx);
8802 raw_spin_unlock_irq(&child_ctx->lock);
8808 * Report the task dead after unscheduling the events so that we
8809 * won't get any samples after PERF_RECORD_EXIT. We can however still
8810 * get a few PERF_RECORD_READ events.
8812 perf_event_task(child, child_ctx, 0);
8814 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8815 perf_event_exit_event(child_event, child_ctx, child);
8817 mutex_unlock(&child_ctx->mutex);
8823 * When a child task exits, feed back event values to parent events.
8825 void perf_event_exit_task(struct task_struct *child)
8827 struct perf_event *event, *tmp;
8830 mutex_lock(&child->perf_event_mutex);
8831 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8833 list_del_init(&event->owner_entry);
8836 * Ensure the list deletion is visible before we clear
8837 * the owner, closes a race against perf_release() where
8838 * we need to serialize on the owner->perf_event_mutex.
8840 smp_store_release(&event->owner, NULL);
8842 mutex_unlock(&child->perf_event_mutex);
8844 for_each_task_context_nr(ctxn)
8845 perf_event_exit_task_context(child, ctxn);
8848 * The perf_event_exit_task_context calls perf_event_task
8849 * with child's task_ctx, which generates EXIT events for
8850 * child contexts and sets child->perf_event_ctxp[] to NULL.
8851 * At this point we need to send EXIT events to cpu contexts.
8853 perf_event_task(child, NULL, 0);
8856 static void perf_free_event(struct perf_event *event,
8857 struct perf_event_context *ctx)
8859 struct perf_event *parent = event->parent;
8861 if (WARN_ON_ONCE(!parent))
8864 mutex_lock(&parent->child_mutex);
8865 list_del_init(&event->child_list);
8866 mutex_unlock(&parent->child_mutex);
8870 raw_spin_lock_irq(&ctx->lock);
8871 perf_group_detach(event);
8872 list_del_event(event, ctx);
8873 raw_spin_unlock_irq(&ctx->lock);
8878 * Free an unexposed, unused context as created by inheritance by
8879 * perf_event_init_task below, used by fork() in case of fail.
8881 * Not all locks are strictly required, but take them anyway to be nice and
8882 * help out with the lockdep assertions.
8884 void perf_event_free_task(struct task_struct *task)
8886 struct perf_event_context *ctx;
8887 struct perf_event *event, *tmp;
8890 for_each_task_context_nr(ctxn) {
8891 ctx = task->perf_event_ctxp[ctxn];
8895 mutex_lock(&ctx->mutex);
8897 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8899 perf_free_event(event, ctx);
8901 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8903 perf_free_event(event, ctx);
8905 if (!list_empty(&ctx->pinned_groups) ||
8906 !list_empty(&ctx->flexible_groups))
8909 mutex_unlock(&ctx->mutex);
8915 void perf_event_delayed_put(struct task_struct *task)
8919 for_each_task_context_nr(ctxn)
8920 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8923 struct file *perf_event_get(unsigned int fd)
8927 file = fget_raw(fd);
8929 return ERR_PTR(-EBADF);
8931 if (file->f_op != &perf_fops) {
8933 return ERR_PTR(-EBADF);
8939 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8942 return ERR_PTR(-EINVAL);
8944 return &event->attr;
8948 * inherit a event from parent task to child task:
8950 static struct perf_event *
8951 inherit_event(struct perf_event *parent_event,
8952 struct task_struct *parent,
8953 struct perf_event_context *parent_ctx,
8954 struct task_struct *child,
8955 struct perf_event *group_leader,
8956 struct perf_event_context *child_ctx)
8958 enum perf_event_active_state parent_state = parent_event->state;
8959 struct perf_event *child_event;
8960 unsigned long flags;
8963 * Instead of creating recursive hierarchies of events,
8964 * we link inherited events back to the original parent,
8965 * which has a filp for sure, which we use as the reference
8968 if (parent_event->parent)
8969 parent_event = parent_event->parent;
8971 child_event = perf_event_alloc(&parent_event->attr,
8974 group_leader, parent_event,
8976 if (IS_ERR(child_event))
8980 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
8981 * must be under the same lock in order to serialize against
8982 * perf_event_release_kernel(), such that either we must observe
8983 * is_orphaned_event() or they will observe us on the child_list.
8985 mutex_lock(&parent_event->child_mutex);
8986 if (is_orphaned_event(parent_event) ||
8987 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8988 mutex_unlock(&parent_event->child_mutex);
8989 free_event(child_event);
8996 * Make the child state follow the state of the parent event,
8997 * not its attr.disabled bit. We hold the parent's mutex,
8998 * so we won't race with perf_event_{en, dis}able_family.
9000 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9001 child_event->state = PERF_EVENT_STATE_INACTIVE;
9003 child_event->state = PERF_EVENT_STATE_OFF;
9005 if (parent_event->attr.freq) {
9006 u64 sample_period = parent_event->hw.sample_period;
9007 struct hw_perf_event *hwc = &child_event->hw;
9009 hwc->sample_period = sample_period;
9010 hwc->last_period = sample_period;
9012 local64_set(&hwc->period_left, sample_period);
9015 child_event->ctx = child_ctx;
9016 child_event->overflow_handler = parent_event->overflow_handler;
9017 child_event->overflow_handler_context
9018 = parent_event->overflow_handler_context;
9021 * Precalculate sample_data sizes
9023 perf_event__header_size(child_event);
9024 perf_event__id_header_size(child_event);
9027 * Link it up in the child's context:
9029 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9030 add_event_to_ctx(child_event, child_ctx);
9031 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9034 * Link this into the parent event's child list
9036 list_add_tail(&child_event->child_list, &parent_event->child_list);
9037 mutex_unlock(&parent_event->child_mutex);
9042 static int inherit_group(struct perf_event *parent_event,
9043 struct task_struct *parent,
9044 struct perf_event_context *parent_ctx,
9045 struct task_struct *child,
9046 struct perf_event_context *child_ctx)
9048 struct perf_event *leader;
9049 struct perf_event *sub;
9050 struct perf_event *child_ctr;
9052 leader = inherit_event(parent_event, parent, parent_ctx,
9053 child, NULL, child_ctx);
9055 return PTR_ERR(leader);
9056 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9057 child_ctr = inherit_event(sub, parent, parent_ctx,
9058 child, leader, child_ctx);
9059 if (IS_ERR(child_ctr))
9060 return PTR_ERR(child_ctr);
9066 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9067 struct perf_event_context *parent_ctx,
9068 struct task_struct *child, int ctxn,
9072 struct perf_event_context *child_ctx;
9074 if (!event->attr.inherit) {
9079 child_ctx = child->perf_event_ctxp[ctxn];
9082 * This is executed from the parent task context, so
9083 * inherit events that have been marked for cloning.
9084 * First allocate and initialize a context for the
9088 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9092 child->perf_event_ctxp[ctxn] = child_ctx;
9095 ret = inherit_group(event, parent, parent_ctx,
9105 * Initialize the perf_event context in task_struct
9107 static int perf_event_init_context(struct task_struct *child, int ctxn)
9109 struct perf_event_context *child_ctx, *parent_ctx;
9110 struct perf_event_context *cloned_ctx;
9111 struct perf_event *event;
9112 struct task_struct *parent = current;
9113 int inherited_all = 1;
9114 unsigned long flags;
9117 if (likely(!parent->perf_event_ctxp[ctxn]))
9121 * If the parent's context is a clone, pin it so it won't get
9124 parent_ctx = perf_pin_task_context(parent, ctxn);
9129 * No need to check if parent_ctx != NULL here; since we saw
9130 * it non-NULL earlier, the only reason for it to become NULL
9131 * is if we exit, and since we're currently in the middle of
9132 * a fork we can't be exiting at the same time.
9136 * Lock the parent list. No need to lock the child - not PID
9137 * hashed yet and not running, so nobody can access it.
9139 mutex_lock(&parent_ctx->mutex);
9142 * We dont have to disable NMIs - we are only looking at
9143 * the list, not manipulating it:
9145 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9146 ret = inherit_task_group(event, parent, parent_ctx,
9147 child, ctxn, &inherited_all);
9153 * We can't hold ctx->lock when iterating the ->flexible_group list due
9154 * to allocations, but we need to prevent rotation because
9155 * rotate_ctx() will change the list from interrupt context.
9157 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9158 parent_ctx->rotate_disable = 1;
9159 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9161 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9162 ret = inherit_task_group(event, parent, parent_ctx,
9163 child, ctxn, &inherited_all);
9168 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9169 parent_ctx->rotate_disable = 0;
9171 child_ctx = child->perf_event_ctxp[ctxn];
9173 if (child_ctx && inherited_all) {
9175 * Mark the child context as a clone of the parent
9176 * context, or of whatever the parent is a clone of.
9178 * Note that if the parent is a clone, the holding of
9179 * parent_ctx->lock avoids it from being uncloned.
9181 cloned_ctx = parent_ctx->parent_ctx;
9183 child_ctx->parent_ctx = cloned_ctx;
9184 child_ctx->parent_gen = parent_ctx->parent_gen;
9186 child_ctx->parent_ctx = parent_ctx;
9187 child_ctx->parent_gen = parent_ctx->generation;
9189 get_ctx(child_ctx->parent_ctx);
9192 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9193 mutex_unlock(&parent_ctx->mutex);
9195 perf_unpin_context(parent_ctx);
9196 put_ctx(parent_ctx);
9202 * Initialize the perf_event context in task_struct
9204 int perf_event_init_task(struct task_struct *child)
9208 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9209 mutex_init(&child->perf_event_mutex);
9210 INIT_LIST_HEAD(&child->perf_event_list);
9212 for_each_task_context_nr(ctxn) {
9213 ret = perf_event_init_context(child, ctxn);
9215 perf_event_free_task(child);
9223 static void __init perf_event_init_all_cpus(void)
9225 struct swevent_htable *swhash;
9228 for_each_possible_cpu(cpu) {
9229 swhash = &per_cpu(swevent_htable, cpu);
9230 mutex_init(&swhash->hlist_mutex);
9231 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9235 static void perf_event_init_cpu(int cpu)
9237 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9239 mutex_lock(&swhash->hlist_mutex);
9240 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
9241 struct swevent_hlist *hlist;
9243 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9245 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9247 mutex_unlock(&swhash->hlist_mutex);
9250 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9251 static void __perf_event_exit_context(void *__info)
9253 struct perf_event_context *ctx = __info;
9254 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9255 struct perf_event *event;
9257 raw_spin_lock(&ctx->lock);
9258 list_for_each_entry(event, &ctx->event_list, event_entry)
9259 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
9260 raw_spin_unlock(&ctx->lock);
9263 static void perf_event_exit_cpu_context(int cpu)
9265 struct perf_event_context *ctx;
9269 idx = srcu_read_lock(&pmus_srcu);
9270 list_for_each_entry_rcu(pmu, &pmus, entry) {
9271 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9273 mutex_lock(&ctx->mutex);
9274 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9275 mutex_unlock(&ctx->mutex);
9277 srcu_read_unlock(&pmus_srcu, idx);
9280 static void perf_event_exit_cpu(int cpu)
9282 perf_event_exit_cpu_context(cpu);
9285 static inline void perf_event_exit_cpu(int cpu) { }
9289 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9293 for_each_online_cpu(cpu)
9294 perf_event_exit_cpu(cpu);
9300 * Run the perf reboot notifier at the very last possible moment so that
9301 * the generic watchdog code runs as long as possible.
9303 static struct notifier_block perf_reboot_notifier = {
9304 .notifier_call = perf_reboot,
9305 .priority = INT_MIN,
9309 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9311 unsigned int cpu = (long)hcpu;
9313 switch (action & ~CPU_TASKS_FROZEN) {
9315 case CPU_UP_PREPARE:
9316 perf_event_init_cpu(cpu);
9319 case CPU_DOWN_PREPARE:
9320 perf_event_exit_cpu(cpu);
9329 void __init perf_event_init(void)
9335 perf_event_init_all_cpus();
9336 init_srcu_struct(&pmus_srcu);
9337 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9338 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9339 perf_pmu_register(&perf_task_clock, NULL, -1);
9341 perf_cpu_notifier(perf_cpu_notify);
9342 register_reboot_notifier(&perf_reboot_notifier);
9344 ret = init_hw_breakpoint();
9345 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9347 /* do not patch jump label more than once per second */
9348 jump_label_rate_limit(&perf_sched_events, HZ);
9351 * Build time assertion that we keep the data_head at the intended
9352 * location. IOW, validation we got the __reserved[] size right.
9354 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9358 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9361 struct perf_pmu_events_attr *pmu_attr =
9362 container_of(attr, struct perf_pmu_events_attr, attr);
9364 if (pmu_attr->event_str)
9365 return sprintf(page, "%s\n", pmu_attr->event_str);
9370 static int __init perf_event_sysfs_init(void)
9375 mutex_lock(&pmus_lock);
9377 ret = bus_register(&pmu_bus);
9381 list_for_each_entry(pmu, &pmus, entry) {
9382 if (!pmu->name || pmu->type < 0)
9385 ret = pmu_dev_alloc(pmu);
9386 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9388 pmu_bus_running = 1;
9392 mutex_unlock(&pmus_lock);
9396 device_initcall(perf_event_sysfs_init);
9398 #ifdef CONFIG_CGROUP_PERF
9399 static struct cgroup_subsys_state *
9400 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9402 struct perf_cgroup *jc;
9404 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9406 return ERR_PTR(-ENOMEM);
9408 jc->info = alloc_percpu(struct perf_cgroup_info);
9411 return ERR_PTR(-ENOMEM);
9417 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9419 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9421 free_percpu(jc->info);
9425 static int __perf_cgroup_move(void *info)
9427 struct task_struct *task = info;
9429 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9434 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9436 struct task_struct *task;
9437 struct cgroup_subsys_state *css;
9439 cgroup_taskset_for_each(task, css, tset)
9440 task_function_call(task, __perf_cgroup_move, task);
9443 struct cgroup_subsys perf_event_cgrp_subsys = {
9444 .css_alloc = perf_cgroup_css_alloc,
9445 .css_free = perf_cgroup_css_free,
9446 .attach = perf_cgroup_attach,
9448 #endif /* CONFIG_CGROUP_PERF */