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 static struct workqueue_struct *perf_wq;
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
74 tfc->ret = tfc->func(tfc->info);
78 * task_function_call - call a function on the cpu on which a task runs
79 * @p: the task to evaluate
80 * @func: the function to be called
81 * @info: the function call argument
83 * Calls the function @func when the task is currently running. This might
84 * be on the current CPU, which just calls the function directly
86 * returns: @func return value, or
87 * -ESRCH - when the process isn't running
88 * -EAGAIN - when the process moved away
91 task_function_call(struct task_struct *p, remote_function_f func, void *info)
93 struct remote_function_call data = {
97 .ret = -ESRCH, /* No such (running) process */
101 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
107 * cpu_function_call - call a function on the cpu
108 * @func: the function to be called
109 * @info: the function call argument
111 * Calls the function @func on the remote cpu.
113 * returns: @func return value or -ENXIO when the cpu is offline
115 static int cpu_function_call(int cpu, remote_function_f func, void *info)
117 struct remote_function_call data = {
121 .ret = -ENXIO, /* No such CPU */
124 smp_call_function_single(cpu, remote_function, &data, 1);
129 static inline struct perf_cpu_context *
130 __get_cpu_context(struct perf_event_context *ctx)
132 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
135 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
136 struct perf_event_context *ctx)
138 raw_spin_lock(&cpuctx->ctx.lock);
140 raw_spin_lock(&ctx->lock);
143 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
144 struct perf_event_context *ctx)
147 raw_spin_unlock(&ctx->lock);
148 raw_spin_unlock(&cpuctx->ctx.lock);
151 #define TASK_TOMBSTONE ((void *)-1L)
153 static bool is_kernel_event(struct perf_event *event)
155 return event->owner == TASK_TOMBSTONE;
159 * On task ctx scheduling...
161 * When !ctx->nr_events a task context will not be scheduled. This means
162 * we can disable the scheduler hooks (for performance) without leaving
163 * pending task ctx state.
165 * This however results in two special cases:
167 * - removing the last event from a task ctx; this is relatively straight
168 * forward and is done in __perf_remove_from_context.
170 * - adding the first event to a task ctx; this is tricky because we cannot
171 * rely on ctx->is_active and therefore cannot use event_function_call().
172 * See perf_install_in_context().
174 * This is because we need a ctx->lock serialized variable (ctx->is_active)
175 * to reliably determine if a particular task/context is scheduled in. The
176 * task_curr() use in task_function_call() is racy in that a remote context
177 * switch is not a single atomic operation.
179 * As is, the situation is 'safe' because we set rq->curr before we do the
180 * actual context switch. This means that task_curr() will fail early, but
181 * we'll continue spinning on ctx->is_active until we've passed
182 * perf_event_task_sched_out().
184 * Without this ctx->lock serialized variable we could have race where we find
185 * the task (and hence the context) would not be active while in fact they are.
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
191 struct perf_event_context *, void *);
193 struct event_function_struct {
194 struct perf_event *event;
199 static int event_function(void *info)
201 struct event_function_struct *efs = info;
202 struct perf_event *event = efs->event;
203 struct perf_event_context *ctx = event->ctx;
204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
205 struct perf_event_context *task_ctx = cpuctx->task_ctx;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx, task_ctx);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx->task != current) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx->is_active);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx != ctx);
235 WARN_ON_ONCE(&cpuctx->ctx != ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
240 perf_ctx_unlock(cpuctx, task_ctx);
245 static void event_function_local(struct perf_event *event, event_f func, void *data)
247 struct event_function_struct efs = {
253 int ret = event_function(&efs);
257 static void event_function_call(struct perf_event *event, event_f func, void *data)
259 struct perf_event_context *ctx = event->ctx;
260 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
261 struct event_function_struct efs = {
267 if (!event->parent) {
269 * If this is a !child event, we must hold ctx::mutex to
270 * stabilize the the event->ctx relation. See
271 * perf_event_ctx_lock().
273 lockdep_assert_held(&ctx->mutex);
277 cpu_function_call(event->cpu, event_function, &efs);
282 if (task == TASK_TOMBSTONE)
285 if (!task_function_call(task, event_function, &efs))
288 raw_spin_lock_irq(&ctx->lock);
290 * Reload the task pointer, it might have been changed by
291 * a concurrent perf_event_context_sched_out().
294 if (task != TASK_TOMBSTONE) {
295 if (ctx->is_active) {
296 raw_spin_unlock_irq(&ctx->lock);
299 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
304 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
305 PERF_FLAG_FD_OUTPUT |\
306 PERF_FLAG_PID_CGROUP |\
307 PERF_FLAG_FD_CLOEXEC)
310 * branch priv levels that need permission checks
312 #define PERF_SAMPLE_BRANCH_PERM_PLM \
313 (PERF_SAMPLE_BRANCH_KERNEL |\
314 PERF_SAMPLE_BRANCH_HV)
317 EVENT_FLEXIBLE = 0x1,
319 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
323 * perf_sched_events : >0 events exist
324 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
326 struct static_key_deferred perf_sched_events __read_mostly;
327 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
328 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
330 static atomic_t nr_mmap_events __read_mostly;
331 static atomic_t nr_comm_events __read_mostly;
332 static atomic_t nr_task_events __read_mostly;
333 static atomic_t nr_freq_events __read_mostly;
334 static atomic_t nr_switch_events __read_mostly;
336 static LIST_HEAD(pmus);
337 static DEFINE_MUTEX(pmus_lock);
338 static struct srcu_struct pmus_srcu;
341 * perf event paranoia level:
342 * -1 - not paranoid at all
343 * 0 - disallow raw tracepoint access for unpriv
344 * 1 - disallow cpu events for unpriv
345 * 2 - disallow kernel profiling for unpriv
347 int sysctl_perf_event_paranoid __read_mostly = 1;
349 /* Minimum for 512 kiB + 1 user control page */
350 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
353 * max perf event sample rate
355 #define DEFAULT_MAX_SAMPLE_RATE 100000
356 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
357 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
359 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
361 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
362 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
364 static int perf_sample_allowed_ns __read_mostly =
365 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
367 static void update_perf_cpu_limits(void)
369 u64 tmp = perf_sample_period_ns;
371 tmp *= sysctl_perf_cpu_time_max_percent;
373 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
376 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
378 int perf_proc_update_handler(struct ctl_table *table, int write,
379 void __user *buffer, size_t *lenp,
382 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
387 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
388 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
389 update_perf_cpu_limits();
394 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
396 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
397 void __user *buffer, size_t *lenp,
400 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
405 update_perf_cpu_limits();
411 * perf samples are done in some very critical code paths (NMIs).
412 * If they take too much CPU time, the system can lock up and not
413 * get any real work done. This will drop the sample rate when
414 * we detect that events are taking too long.
416 #define NR_ACCUMULATED_SAMPLES 128
417 static DEFINE_PER_CPU(u64, running_sample_length);
419 static void perf_duration_warn(struct irq_work *w)
421 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
422 u64 avg_local_sample_len;
423 u64 local_samples_len;
425 local_samples_len = __this_cpu_read(running_sample_length);
426 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
428 printk_ratelimited(KERN_WARNING
429 "perf interrupt took too long (%lld > %lld), lowering "
430 "kernel.perf_event_max_sample_rate to %d\n",
431 avg_local_sample_len, allowed_ns >> 1,
432 sysctl_perf_event_sample_rate);
435 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
437 void perf_sample_event_took(u64 sample_len_ns)
439 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
440 u64 avg_local_sample_len;
441 u64 local_samples_len;
446 /* decay the counter by 1 average sample */
447 local_samples_len = __this_cpu_read(running_sample_length);
448 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
449 local_samples_len += sample_len_ns;
450 __this_cpu_write(running_sample_length, local_samples_len);
453 * note: this will be biased artifically low until we have
454 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
455 * from having to maintain a count.
457 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
459 if (avg_local_sample_len <= allowed_ns)
462 if (max_samples_per_tick <= 1)
465 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
466 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
467 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
469 update_perf_cpu_limits();
471 if (!irq_work_queue(&perf_duration_work)) {
472 early_printk("perf interrupt took too long (%lld > %lld), lowering "
473 "kernel.perf_event_max_sample_rate to %d\n",
474 avg_local_sample_len, allowed_ns >> 1,
475 sysctl_perf_event_sample_rate);
479 static atomic64_t perf_event_id;
481 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
482 enum event_type_t event_type);
484 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
485 enum event_type_t event_type,
486 struct task_struct *task);
488 static void update_context_time(struct perf_event_context *ctx);
489 static u64 perf_event_time(struct perf_event *event);
491 void __weak perf_event_print_debug(void) { }
493 extern __weak const char *perf_pmu_name(void)
498 static inline u64 perf_clock(void)
500 return local_clock();
503 static inline u64 perf_event_clock(struct perf_event *event)
505 return event->clock();
508 #ifdef CONFIG_CGROUP_PERF
511 perf_cgroup_match(struct perf_event *event)
513 struct perf_event_context *ctx = event->ctx;
514 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
516 /* @event doesn't care about cgroup */
520 /* wants specific cgroup scope but @cpuctx isn't associated with any */
525 * Cgroup scoping is recursive. An event enabled for a cgroup is
526 * also enabled for all its descendant cgroups. If @cpuctx's
527 * cgroup is a descendant of @event's (the test covers identity
528 * case), it's a match.
530 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
531 event->cgrp->css.cgroup);
534 static inline void perf_detach_cgroup(struct perf_event *event)
536 css_put(&event->cgrp->css);
540 static inline int is_cgroup_event(struct perf_event *event)
542 return event->cgrp != NULL;
545 static inline u64 perf_cgroup_event_time(struct perf_event *event)
547 struct perf_cgroup_info *t;
549 t = per_cpu_ptr(event->cgrp->info, event->cpu);
553 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
555 struct perf_cgroup_info *info;
560 info = this_cpu_ptr(cgrp->info);
562 info->time += now - info->timestamp;
563 info->timestamp = now;
566 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
568 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
570 __update_cgrp_time(cgrp_out);
573 static inline void update_cgrp_time_from_event(struct perf_event *event)
575 struct perf_cgroup *cgrp;
578 * ensure we access cgroup data only when needed and
579 * when we know the cgroup is pinned (css_get)
581 if (!is_cgroup_event(event))
584 cgrp = perf_cgroup_from_task(current, event->ctx);
586 * Do not update time when cgroup is not active
588 if (cgrp == event->cgrp)
589 __update_cgrp_time(event->cgrp);
593 perf_cgroup_set_timestamp(struct task_struct *task,
594 struct perf_event_context *ctx)
596 struct perf_cgroup *cgrp;
597 struct perf_cgroup_info *info;
600 * ctx->lock held by caller
601 * ensure we do not access cgroup data
602 * unless we have the cgroup pinned (css_get)
604 if (!task || !ctx->nr_cgroups)
607 cgrp = perf_cgroup_from_task(task, ctx);
608 info = this_cpu_ptr(cgrp->info);
609 info->timestamp = ctx->timestamp;
612 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
613 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
616 * reschedule events based on the cgroup constraint of task.
618 * mode SWOUT : schedule out everything
619 * mode SWIN : schedule in based on cgroup for next
621 static void perf_cgroup_switch(struct task_struct *task, int mode)
623 struct perf_cpu_context *cpuctx;
628 * disable interrupts to avoid geting nr_cgroup
629 * changes via __perf_event_disable(). Also
632 local_irq_save(flags);
635 * we reschedule only in the presence of cgroup
636 * constrained events.
639 list_for_each_entry_rcu(pmu, &pmus, entry) {
640 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
641 if (cpuctx->unique_pmu != pmu)
642 continue; /* ensure we process each cpuctx once */
645 * perf_cgroup_events says at least one
646 * context on this CPU has cgroup events.
648 * ctx->nr_cgroups reports the number of cgroup
649 * events for a context.
651 if (cpuctx->ctx.nr_cgroups > 0) {
652 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
653 perf_pmu_disable(cpuctx->ctx.pmu);
655 if (mode & PERF_CGROUP_SWOUT) {
656 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
658 * must not be done before ctxswout due
659 * to event_filter_match() in event_sched_out()
664 if (mode & PERF_CGROUP_SWIN) {
665 WARN_ON_ONCE(cpuctx->cgrp);
667 * set cgrp before ctxsw in to allow
668 * event_filter_match() to not have to pass
670 * we pass the cpuctx->ctx to perf_cgroup_from_task()
671 * because cgorup events are only per-cpu
673 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
674 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
676 perf_pmu_enable(cpuctx->ctx.pmu);
677 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
681 local_irq_restore(flags);
684 static inline void perf_cgroup_sched_out(struct task_struct *task,
685 struct task_struct *next)
687 struct perf_cgroup *cgrp1;
688 struct perf_cgroup *cgrp2 = NULL;
692 * we come here when we know perf_cgroup_events > 0
693 * we do not need to pass the ctx here because we know
694 * we are holding the rcu lock
696 cgrp1 = perf_cgroup_from_task(task, NULL);
697 cgrp2 = perf_cgroup_from_task(next, NULL);
700 * only schedule out current cgroup events if we know
701 * that we are switching to a different cgroup. Otherwise,
702 * do no touch the cgroup events.
705 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
710 static inline void perf_cgroup_sched_in(struct task_struct *prev,
711 struct task_struct *task)
713 struct perf_cgroup *cgrp1;
714 struct perf_cgroup *cgrp2 = NULL;
718 * we come here when we know perf_cgroup_events > 0
719 * we do not need to pass the ctx here because we know
720 * we are holding the rcu lock
722 cgrp1 = perf_cgroup_from_task(task, NULL);
723 cgrp2 = perf_cgroup_from_task(prev, NULL);
726 * only need to schedule in cgroup events if we are changing
727 * cgroup during ctxsw. Cgroup events were not scheduled
728 * out of ctxsw out if that was not the case.
731 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
736 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
737 struct perf_event_attr *attr,
738 struct perf_event *group_leader)
740 struct perf_cgroup *cgrp;
741 struct cgroup_subsys_state *css;
742 struct fd f = fdget(fd);
748 css = css_tryget_online_from_dir(f.file->f_path.dentry,
749 &perf_event_cgrp_subsys);
755 cgrp = container_of(css, struct perf_cgroup, css);
759 * all events in a group must monitor
760 * the same cgroup because a task belongs
761 * to only one perf cgroup at a time
763 if (group_leader && group_leader->cgrp != cgrp) {
764 perf_detach_cgroup(event);
773 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
775 struct perf_cgroup_info *t;
776 t = per_cpu_ptr(event->cgrp->info, event->cpu);
777 event->shadow_ctx_time = now - t->timestamp;
781 perf_cgroup_defer_enabled(struct perf_event *event)
784 * when the current task's perf cgroup does not match
785 * the event's, we need to remember to call the
786 * perf_mark_enable() function the first time a task with
787 * a matching perf cgroup is scheduled in.
789 if (is_cgroup_event(event) && !perf_cgroup_match(event))
790 event->cgrp_defer_enabled = 1;
794 perf_cgroup_mark_enabled(struct perf_event *event,
795 struct perf_event_context *ctx)
797 struct perf_event *sub;
798 u64 tstamp = perf_event_time(event);
800 if (!event->cgrp_defer_enabled)
803 event->cgrp_defer_enabled = 0;
805 event->tstamp_enabled = tstamp - event->total_time_enabled;
806 list_for_each_entry(sub, &event->sibling_list, group_entry) {
807 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
808 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
809 sub->cgrp_defer_enabled = 0;
813 #else /* !CONFIG_CGROUP_PERF */
816 perf_cgroup_match(struct perf_event *event)
821 static inline void perf_detach_cgroup(struct perf_event *event)
824 static inline int is_cgroup_event(struct perf_event *event)
829 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
834 static inline void update_cgrp_time_from_event(struct perf_event *event)
838 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
842 static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
847 static inline void perf_cgroup_sched_in(struct task_struct *prev,
848 struct task_struct *task)
852 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
853 struct perf_event_attr *attr,
854 struct perf_event *group_leader)
860 perf_cgroup_set_timestamp(struct task_struct *task,
861 struct perf_event_context *ctx)
866 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
871 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
875 static inline u64 perf_cgroup_event_time(struct perf_event *event)
881 perf_cgroup_defer_enabled(struct perf_event *event)
886 perf_cgroup_mark_enabled(struct perf_event *event,
887 struct perf_event_context *ctx)
893 * set default to be dependent on timer tick just
896 #define PERF_CPU_HRTIMER (1000 / HZ)
898 * function must be called with interrupts disbled
900 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
902 struct perf_cpu_context *cpuctx;
905 WARN_ON(!irqs_disabled());
907 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
908 rotations = perf_rotate_context(cpuctx);
910 raw_spin_lock(&cpuctx->hrtimer_lock);
912 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
914 cpuctx->hrtimer_active = 0;
915 raw_spin_unlock(&cpuctx->hrtimer_lock);
917 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
920 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
922 struct hrtimer *timer = &cpuctx->hrtimer;
923 struct pmu *pmu = cpuctx->ctx.pmu;
926 /* no multiplexing needed for SW PMU */
927 if (pmu->task_ctx_nr == perf_sw_context)
931 * check default is sane, if not set then force to
932 * default interval (1/tick)
934 interval = pmu->hrtimer_interval_ms;
936 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
938 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
940 raw_spin_lock_init(&cpuctx->hrtimer_lock);
941 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
942 timer->function = perf_mux_hrtimer_handler;
945 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
947 struct hrtimer *timer = &cpuctx->hrtimer;
948 struct pmu *pmu = cpuctx->ctx.pmu;
952 if (pmu->task_ctx_nr == perf_sw_context)
955 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
956 if (!cpuctx->hrtimer_active) {
957 cpuctx->hrtimer_active = 1;
958 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
959 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
961 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
966 void perf_pmu_disable(struct pmu *pmu)
968 int *count = this_cpu_ptr(pmu->pmu_disable_count);
970 pmu->pmu_disable(pmu);
973 void perf_pmu_enable(struct pmu *pmu)
975 int *count = this_cpu_ptr(pmu->pmu_disable_count);
977 pmu->pmu_enable(pmu);
980 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
983 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
984 * perf_event_task_tick() are fully serialized because they're strictly cpu
985 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
986 * disabled, while perf_event_task_tick is called from IRQ context.
988 static void perf_event_ctx_activate(struct perf_event_context *ctx)
990 struct list_head *head = this_cpu_ptr(&active_ctx_list);
992 WARN_ON(!irqs_disabled());
994 WARN_ON(!list_empty(&ctx->active_ctx_list));
996 list_add(&ctx->active_ctx_list, head);
999 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1001 WARN_ON(!irqs_disabled());
1003 WARN_ON(list_empty(&ctx->active_ctx_list));
1005 list_del_init(&ctx->active_ctx_list);
1008 static void get_ctx(struct perf_event_context *ctx)
1010 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1013 static void free_ctx(struct rcu_head *head)
1015 struct perf_event_context *ctx;
1017 ctx = container_of(head, struct perf_event_context, rcu_head);
1018 kfree(ctx->task_ctx_data);
1022 static void put_ctx(struct perf_event_context *ctx)
1024 if (atomic_dec_and_test(&ctx->refcount)) {
1025 if (ctx->parent_ctx)
1026 put_ctx(ctx->parent_ctx);
1027 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1028 put_task_struct(ctx->task);
1029 call_rcu(&ctx->rcu_head, free_ctx);
1034 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1035 * perf_pmu_migrate_context() we need some magic.
1037 * Those places that change perf_event::ctx will hold both
1038 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1040 * Lock ordering is by mutex address. There are two other sites where
1041 * perf_event_context::mutex nests and those are:
1043 * - perf_event_exit_task_context() [ child , 0 ]
1044 * __perf_event_exit_task()
1045 * sync_child_event()
1046 * put_event() [ parent, 1 ]
1048 * - perf_event_init_context() [ parent, 0 ]
1049 * inherit_task_group()
1052 * perf_event_alloc()
1054 * perf_try_init_event() [ child , 1 ]
1056 * While it appears there is an obvious deadlock here -- the parent and child
1057 * nesting levels are inverted between the two. This is in fact safe because
1058 * life-time rules separate them. That is an exiting task cannot fork, and a
1059 * spawning task cannot (yet) exit.
1061 * But remember that that these are parent<->child context relations, and
1062 * migration does not affect children, therefore these two orderings should not
1065 * The change in perf_event::ctx does not affect children (as claimed above)
1066 * because the sys_perf_event_open() case will install a new event and break
1067 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1068 * concerned with cpuctx and that doesn't have children.
1070 * The places that change perf_event::ctx will issue:
1072 * perf_remove_from_context();
1073 * synchronize_rcu();
1074 * perf_install_in_context();
1076 * to affect the change. The remove_from_context() + synchronize_rcu() should
1077 * quiesce the event, after which we can install it in the new location. This
1078 * means that only external vectors (perf_fops, prctl) can perturb the event
1079 * while in transit. Therefore all such accessors should also acquire
1080 * perf_event_context::mutex to serialize against this.
1082 * However; because event->ctx can change while we're waiting to acquire
1083 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1087 * task_struct::perf_event_mutex
1088 * perf_event_context::mutex
1089 * perf_event::child_mutex;
1090 * perf_event_context::lock
1091 * perf_event::mmap_mutex
1094 static struct perf_event_context *
1095 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1097 struct perf_event_context *ctx;
1101 ctx = ACCESS_ONCE(event->ctx);
1102 if (!atomic_inc_not_zero(&ctx->refcount)) {
1108 mutex_lock_nested(&ctx->mutex, nesting);
1109 if (event->ctx != ctx) {
1110 mutex_unlock(&ctx->mutex);
1118 static inline struct perf_event_context *
1119 perf_event_ctx_lock(struct perf_event *event)
1121 return perf_event_ctx_lock_nested(event, 0);
1124 static void perf_event_ctx_unlock(struct perf_event *event,
1125 struct perf_event_context *ctx)
1127 mutex_unlock(&ctx->mutex);
1132 * This must be done under the ctx->lock, such as to serialize against
1133 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1134 * calling scheduler related locks and ctx->lock nests inside those.
1136 static __must_check struct perf_event_context *
1137 unclone_ctx(struct perf_event_context *ctx)
1139 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1141 lockdep_assert_held(&ctx->lock);
1144 ctx->parent_ctx = NULL;
1150 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1153 * only top level events have the pid namespace they were created in
1156 event = event->parent;
1158 return task_tgid_nr_ns(p, event->ns);
1161 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1164 * only top level events have the pid namespace they were created in
1167 event = event->parent;
1169 return task_pid_nr_ns(p, event->ns);
1173 * If we inherit events we want to return the parent event id
1176 static u64 primary_event_id(struct perf_event *event)
1181 id = event->parent->id;
1187 * Get the perf_event_context for a task and lock it.
1189 * This has to cope with with the fact that until it is locked,
1190 * the context could get moved to another task.
1192 static struct perf_event_context *
1193 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1195 struct perf_event_context *ctx;
1199 * One of the few rules of preemptible RCU is that one cannot do
1200 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1201 * part of the read side critical section was irqs-enabled -- see
1202 * rcu_read_unlock_special().
1204 * Since ctx->lock nests under rq->lock we must ensure the entire read
1205 * side critical section has interrupts disabled.
1207 local_irq_save(*flags);
1209 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1212 * If this context is a clone of another, it might
1213 * get swapped for another underneath us by
1214 * perf_event_task_sched_out, though the
1215 * rcu_read_lock() protects us from any context
1216 * getting freed. Lock the context and check if it
1217 * got swapped before we could get the lock, and retry
1218 * if so. If we locked the right context, then it
1219 * can't get swapped on us any more.
1221 raw_spin_lock(&ctx->lock);
1222 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1223 raw_spin_unlock(&ctx->lock);
1225 local_irq_restore(*flags);
1229 if (ctx->task == TASK_TOMBSTONE ||
1230 !atomic_inc_not_zero(&ctx->refcount)) {
1231 raw_spin_unlock(&ctx->lock);
1234 WARN_ON_ONCE(ctx->task != task);
1239 local_irq_restore(*flags);
1244 * Get the context for a task and increment its pin_count so it
1245 * can't get swapped to another task. This also increments its
1246 * reference count so that the context can't get freed.
1248 static struct perf_event_context *
1249 perf_pin_task_context(struct task_struct *task, int ctxn)
1251 struct perf_event_context *ctx;
1252 unsigned long flags;
1254 ctx = perf_lock_task_context(task, ctxn, &flags);
1257 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1262 static void perf_unpin_context(struct perf_event_context *ctx)
1264 unsigned long flags;
1266 raw_spin_lock_irqsave(&ctx->lock, flags);
1268 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1272 * Update the record of the current time in a context.
1274 static void update_context_time(struct perf_event_context *ctx)
1276 u64 now = perf_clock();
1278 ctx->time += now - ctx->timestamp;
1279 ctx->timestamp = now;
1282 static u64 perf_event_time(struct perf_event *event)
1284 struct perf_event_context *ctx = event->ctx;
1286 if (is_cgroup_event(event))
1287 return perf_cgroup_event_time(event);
1289 return ctx ? ctx->time : 0;
1293 * Update the total_time_enabled and total_time_running fields for a event.
1294 * The caller of this function needs to hold the ctx->lock.
1296 static void update_event_times(struct perf_event *event)
1298 struct perf_event_context *ctx = event->ctx;
1301 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1302 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1305 * in cgroup mode, time_enabled represents
1306 * the time the event was enabled AND active
1307 * tasks were in the monitored cgroup. This is
1308 * independent of the activity of the context as
1309 * there may be a mix of cgroup and non-cgroup events.
1311 * That is why we treat cgroup events differently
1314 if (is_cgroup_event(event))
1315 run_end = perf_cgroup_event_time(event);
1316 else if (ctx->is_active)
1317 run_end = ctx->time;
1319 run_end = event->tstamp_stopped;
1321 event->total_time_enabled = run_end - event->tstamp_enabled;
1323 if (event->state == PERF_EVENT_STATE_INACTIVE)
1324 run_end = event->tstamp_stopped;
1326 run_end = perf_event_time(event);
1328 event->total_time_running = run_end - event->tstamp_running;
1333 * Update total_time_enabled and total_time_running for all events in a group.
1335 static void update_group_times(struct perf_event *leader)
1337 struct perf_event *event;
1339 update_event_times(leader);
1340 list_for_each_entry(event, &leader->sibling_list, group_entry)
1341 update_event_times(event);
1344 static struct list_head *
1345 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1347 if (event->attr.pinned)
1348 return &ctx->pinned_groups;
1350 return &ctx->flexible_groups;
1354 * Add a event from the lists for its context.
1355 * Must be called with ctx->mutex and ctx->lock held.
1358 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1360 lockdep_assert_held(&ctx->lock);
1362 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1363 event->attach_state |= PERF_ATTACH_CONTEXT;
1366 * If we're a stand alone event or group leader, we go to the context
1367 * list, group events are kept attached to the group so that
1368 * perf_group_detach can, at all times, locate all siblings.
1370 if (event->group_leader == event) {
1371 struct list_head *list;
1373 if (is_software_event(event))
1374 event->group_flags |= PERF_GROUP_SOFTWARE;
1376 list = ctx_group_list(event, ctx);
1377 list_add_tail(&event->group_entry, list);
1380 if (is_cgroup_event(event))
1383 list_add_rcu(&event->event_entry, &ctx->event_list);
1385 if (event->attr.inherit_stat)
1392 * Initialize event state based on the perf_event_attr::disabled.
1394 static inline void perf_event__state_init(struct perf_event *event)
1396 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1397 PERF_EVENT_STATE_INACTIVE;
1400 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1402 int entry = sizeof(u64); /* value */
1406 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1407 size += sizeof(u64);
1409 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1410 size += sizeof(u64);
1412 if (event->attr.read_format & PERF_FORMAT_ID)
1413 entry += sizeof(u64);
1415 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1417 size += sizeof(u64);
1421 event->read_size = size;
1424 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1426 struct perf_sample_data *data;
1429 if (sample_type & PERF_SAMPLE_IP)
1430 size += sizeof(data->ip);
1432 if (sample_type & PERF_SAMPLE_ADDR)
1433 size += sizeof(data->addr);
1435 if (sample_type & PERF_SAMPLE_PERIOD)
1436 size += sizeof(data->period);
1438 if (sample_type & PERF_SAMPLE_WEIGHT)
1439 size += sizeof(data->weight);
1441 if (sample_type & PERF_SAMPLE_READ)
1442 size += event->read_size;
1444 if (sample_type & PERF_SAMPLE_DATA_SRC)
1445 size += sizeof(data->data_src.val);
1447 if (sample_type & PERF_SAMPLE_TRANSACTION)
1448 size += sizeof(data->txn);
1450 event->header_size = size;
1454 * Called at perf_event creation and when events are attached/detached from a
1457 static void perf_event__header_size(struct perf_event *event)
1459 __perf_event_read_size(event,
1460 event->group_leader->nr_siblings);
1461 __perf_event_header_size(event, event->attr.sample_type);
1464 static void perf_event__id_header_size(struct perf_event *event)
1466 struct perf_sample_data *data;
1467 u64 sample_type = event->attr.sample_type;
1470 if (sample_type & PERF_SAMPLE_TID)
1471 size += sizeof(data->tid_entry);
1473 if (sample_type & PERF_SAMPLE_TIME)
1474 size += sizeof(data->time);
1476 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1477 size += sizeof(data->id);
1479 if (sample_type & PERF_SAMPLE_ID)
1480 size += sizeof(data->id);
1482 if (sample_type & PERF_SAMPLE_STREAM_ID)
1483 size += sizeof(data->stream_id);
1485 if (sample_type & PERF_SAMPLE_CPU)
1486 size += sizeof(data->cpu_entry);
1488 event->id_header_size = size;
1491 static bool perf_event_validate_size(struct perf_event *event)
1494 * The values computed here will be over-written when we actually
1497 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1498 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1499 perf_event__id_header_size(event);
1502 * Sum the lot; should not exceed the 64k limit we have on records.
1503 * Conservative limit to allow for callchains and other variable fields.
1505 if (event->read_size + event->header_size +
1506 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1512 static void perf_group_attach(struct perf_event *event)
1514 struct perf_event *group_leader = event->group_leader, *pos;
1517 * We can have double attach due to group movement in perf_event_open.
1519 if (event->attach_state & PERF_ATTACH_GROUP)
1522 event->attach_state |= PERF_ATTACH_GROUP;
1524 if (group_leader == event)
1527 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1529 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1530 !is_software_event(event))
1531 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1533 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1534 group_leader->nr_siblings++;
1536 perf_event__header_size(group_leader);
1538 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1539 perf_event__header_size(pos);
1543 * Remove a event from the lists for its context.
1544 * Must be called with ctx->mutex and ctx->lock held.
1547 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1549 struct perf_cpu_context *cpuctx;
1551 WARN_ON_ONCE(event->ctx != ctx);
1552 lockdep_assert_held(&ctx->lock);
1555 * We can have double detach due to exit/hot-unplug + close.
1557 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1560 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1562 if (is_cgroup_event(event)) {
1565 * Because cgroup events are always per-cpu events, this will
1566 * always be called from the right CPU.
1568 cpuctx = __get_cpu_context(ctx);
1570 * If there are no more cgroup events then clear cgrp to avoid
1571 * stale pointer in update_cgrp_time_from_cpuctx().
1573 if (!ctx->nr_cgroups)
1574 cpuctx->cgrp = NULL;
1578 if (event->attr.inherit_stat)
1581 list_del_rcu(&event->event_entry);
1583 if (event->group_leader == event)
1584 list_del_init(&event->group_entry);
1586 update_group_times(event);
1589 * If event was in error state, then keep it
1590 * that way, otherwise bogus counts will be
1591 * returned on read(). The only way to get out
1592 * of error state is by explicit re-enabling
1595 if (event->state > PERF_EVENT_STATE_OFF)
1596 event->state = PERF_EVENT_STATE_OFF;
1601 static void perf_group_detach(struct perf_event *event)
1603 struct perf_event *sibling, *tmp;
1604 struct list_head *list = NULL;
1607 * We can have double detach due to exit/hot-unplug + close.
1609 if (!(event->attach_state & PERF_ATTACH_GROUP))
1612 event->attach_state &= ~PERF_ATTACH_GROUP;
1615 * If this is a sibling, remove it from its group.
1617 if (event->group_leader != event) {
1618 list_del_init(&event->group_entry);
1619 event->group_leader->nr_siblings--;
1623 if (!list_empty(&event->group_entry))
1624 list = &event->group_entry;
1627 * If this was a group event with sibling events then
1628 * upgrade the siblings to singleton events by adding them
1629 * to whatever list we are on.
1631 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1633 list_move_tail(&sibling->group_entry, list);
1634 sibling->group_leader = sibling;
1636 /* Inherit group flags from the previous leader */
1637 sibling->group_flags = event->group_flags;
1639 WARN_ON_ONCE(sibling->ctx != event->ctx);
1643 perf_event__header_size(event->group_leader);
1645 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1646 perf_event__header_size(tmp);
1650 * User event without the task.
1652 static bool is_orphaned_event(struct perf_event *event)
1654 return event && !is_kernel_event(event) && !event->owner;
1658 * Event has a parent but parent's task finished and it's
1659 * alive only because of children holding refference.
1661 static bool is_orphaned_child(struct perf_event *event)
1663 return is_orphaned_event(event->parent);
1666 static void orphans_remove_work(struct work_struct *work);
1668 static void schedule_orphans_remove(struct perf_event_context *ctx)
1670 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1673 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1675 ctx->orphans_remove_sched = true;
1679 static int __init perf_workqueue_init(void)
1681 perf_wq = create_singlethread_workqueue("perf");
1682 WARN(!perf_wq, "failed to create perf workqueue\n");
1683 return perf_wq ? 0 : -1;
1686 core_initcall(perf_workqueue_init);
1688 static inline int pmu_filter_match(struct perf_event *event)
1690 struct pmu *pmu = event->pmu;
1691 return pmu->filter_match ? pmu->filter_match(event) : 1;
1695 event_filter_match(struct perf_event *event)
1697 return (event->cpu == -1 || event->cpu == smp_processor_id())
1698 && perf_cgroup_match(event) && pmu_filter_match(event);
1702 event_sched_out(struct perf_event *event,
1703 struct perf_cpu_context *cpuctx,
1704 struct perf_event_context *ctx)
1706 u64 tstamp = perf_event_time(event);
1709 WARN_ON_ONCE(event->ctx != ctx);
1710 lockdep_assert_held(&ctx->lock);
1713 * An event which could not be activated because of
1714 * filter mismatch still needs to have its timings
1715 * maintained, otherwise bogus information is return
1716 * via read() for time_enabled, time_running:
1718 if (event->state == PERF_EVENT_STATE_INACTIVE
1719 && !event_filter_match(event)) {
1720 delta = tstamp - event->tstamp_stopped;
1721 event->tstamp_running += delta;
1722 event->tstamp_stopped = tstamp;
1725 if (event->state != PERF_EVENT_STATE_ACTIVE)
1728 perf_pmu_disable(event->pmu);
1730 event->state = PERF_EVENT_STATE_INACTIVE;
1731 if (event->pending_disable) {
1732 event->pending_disable = 0;
1733 event->state = PERF_EVENT_STATE_OFF;
1735 event->tstamp_stopped = tstamp;
1736 event->pmu->del(event, 0);
1739 if (!is_software_event(event))
1740 cpuctx->active_oncpu--;
1741 if (!--ctx->nr_active)
1742 perf_event_ctx_deactivate(ctx);
1743 if (event->attr.freq && event->attr.sample_freq)
1745 if (event->attr.exclusive || !cpuctx->active_oncpu)
1746 cpuctx->exclusive = 0;
1748 if (is_orphaned_child(event))
1749 schedule_orphans_remove(ctx);
1751 perf_pmu_enable(event->pmu);
1755 group_sched_out(struct perf_event *group_event,
1756 struct perf_cpu_context *cpuctx,
1757 struct perf_event_context *ctx)
1759 struct perf_event *event;
1760 int state = group_event->state;
1762 event_sched_out(group_event, cpuctx, ctx);
1765 * Schedule out siblings (if any):
1767 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1768 event_sched_out(event, cpuctx, ctx);
1770 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1771 cpuctx->exclusive = 0;
1775 * Cross CPU call to remove a performance event
1777 * We disable the event on the hardware level first. After that we
1778 * remove it from the context list.
1781 __perf_remove_from_context(struct perf_event *event,
1782 struct perf_cpu_context *cpuctx,
1783 struct perf_event_context *ctx,
1786 bool detach_group = (unsigned long)info;
1788 event_sched_out(event, cpuctx, ctx);
1790 perf_group_detach(event);
1791 list_del_event(event, ctx);
1793 if (!ctx->nr_events && ctx->is_active) {
1796 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1797 cpuctx->task_ctx = NULL;
1803 * Remove the event from a task's (or a CPU's) list of events.
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 is OK when called from perf_release since
1808 * that only calls us on the top-level context, which can't be a clone.
1809 * When called from perf_event_exit_task, it's OK because the
1810 * context has been detached from its task.
1812 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1814 lockdep_assert_held(&event->ctx->mutex);
1816 event_function_call(event, __perf_remove_from_context,
1817 (void *)(unsigned long)detach_group);
1821 * Cross CPU call to disable a performance event
1823 static void __perf_event_disable(struct perf_event *event,
1824 struct perf_cpu_context *cpuctx,
1825 struct perf_event_context *ctx,
1828 if (event->state < PERF_EVENT_STATE_INACTIVE)
1831 update_context_time(ctx);
1832 update_cgrp_time_from_event(event);
1833 update_group_times(event);
1834 if (event == event->group_leader)
1835 group_sched_out(event, cpuctx, ctx);
1837 event_sched_out(event, cpuctx, ctx);
1838 event->state = PERF_EVENT_STATE_OFF;
1844 * If event->ctx is a cloned context, callers must make sure that
1845 * every task struct that event->ctx->task could possibly point to
1846 * remains valid. This condition is satisifed when called through
1847 * perf_event_for_each_child or perf_event_for_each because they
1848 * hold the top-level event's child_mutex, so any descendant that
1849 * goes to exit will block in sync_child_event.
1850 * When called from perf_pending_event it's OK because event->ctx
1851 * is the current context on this CPU and preemption is disabled,
1852 * hence we can't get into perf_event_task_sched_out for this context.
1854 static void _perf_event_disable(struct perf_event *event)
1856 struct perf_event_context *ctx = event->ctx;
1858 raw_spin_lock_irq(&ctx->lock);
1859 if (event->state <= PERF_EVENT_STATE_OFF) {
1860 raw_spin_unlock_irq(&ctx->lock);
1863 raw_spin_unlock_irq(&ctx->lock);
1865 event_function_call(event, __perf_event_disable, NULL);
1868 void perf_event_disable_local(struct perf_event *event)
1870 event_function_local(event, __perf_event_disable, NULL);
1874 * Strictly speaking kernel users cannot create groups and therefore this
1875 * interface does not need the perf_event_ctx_lock() magic.
1877 void perf_event_disable(struct perf_event *event)
1879 struct perf_event_context *ctx;
1881 ctx = perf_event_ctx_lock(event);
1882 _perf_event_disable(event);
1883 perf_event_ctx_unlock(event, ctx);
1885 EXPORT_SYMBOL_GPL(perf_event_disable);
1887 static void perf_set_shadow_time(struct perf_event *event,
1888 struct perf_event_context *ctx,
1892 * use the correct time source for the time snapshot
1894 * We could get by without this by leveraging the
1895 * fact that to get to this function, the caller
1896 * has most likely already called update_context_time()
1897 * and update_cgrp_time_xx() and thus both timestamp
1898 * are identical (or very close). Given that tstamp is,
1899 * already adjusted for cgroup, we could say that:
1900 * tstamp - ctx->timestamp
1902 * tstamp - cgrp->timestamp.
1904 * Then, in perf_output_read(), the calculation would
1905 * work with no changes because:
1906 * - event is guaranteed scheduled in
1907 * - no scheduled out in between
1908 * - thus the timestamp would be the same
1910 * But this is a bit hairy.
1912 * So instead, we have an explicit cgroup call to remain
1913 * within the time time source all along. We believe it
1914 * is cleaner and simpler to understand.
1916 if (is_cgroup_event(event))
1917 perf_cgroup_set_shadow_time(event, tstamp);
1919 event->shadow_ctx_time = tstamp - ctx->timestamp;
1922 #define MAX_INTERRUPTS (~0ULL)
1924 static void perf_log_throttle(struct perf_event *event, int enable);
1925 static void perf_log_itrace_start(struct perf_event *event);
1928 event_sched_in(struct perf_event *event,
1929 struct perf_cpu_context *cpuctx,
1930 struct perf_event_context *ctx)
1932 u64 tstamp = perf_event_time(event);
1935 lockdep_assert_held(&ctx->lock);
1937 if (event->state <= PERF_EVENT_STATE_OFF)
1940 event->state = PERF_EVENT_STATE_ACTIVE;
1941 event->oncpu = smp_processor_id();
1944 * Unthrottle events, since we scheduled we might have missed several
1945 * ticks already, also for a heavily scheduling task there is little
1946 * guarantee it'll get a tick in a timely manner.
1948 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1949 perf_log_throttle(event, 1);
1950 event->hw.interrupts = 0;
1954 * The new state must be visible before we turn it on in the hardware:
1958 perf_pmu_disable(event->pmu);
1960 perf_set_shadow_time(event, ctx, tstamp);
1962 perf_log_itrace_start(event);
1964 if (event->pmu->add(event, PERF_EF_START)) {
1965 event->state = PERF_EVENT_STATE_INACTIVE;
1971 event->tstamp_running += tstamp - event->tstamp_stopped;
1973 if (!is_software_event(event))
1974 cpuctx->active_oncpu++;
1975 if (!ctx->nr_active++)
1976 perf_event_ctx_activate(ctx);
1977 if (event->attr.freq && event->attr.sample_freq)
1980 if (event->attr.exclusive)
1981 cpuctx->exclusive = 1;
1983 if (is_orphaned_child(event))
1984 schedule_orphans_remove(ctx);
1987 perf_pmu_enable(event->pmu);
1993 group_sched_in(struct perf_event *group_event,
1994 struct perf_cpu_context *cpuctx,
1995 struct perf_event_context *ctx)
1997 struct perf_event *event, *partial_group = NULL;
1998 struct pmu *pmu = ctx->pmu;
1999 u64 now = ctx->time;
2000 bool simulate = false;
2002 if (group_event->state == PERF_EVENT_STATE_OFF)
2005 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2007 if (event_sched_in(group_event, cpuctx, ctx)) {
2008 pmu->cancel_txn(pmu);
2009 perf_mux_hrtimer_restart(cpuctx);
2014 * Schedule in siblings as one group (if any):
2016 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2017 if (event_sched_in(event, cpuctx, ctx)) {
2018 partial_group = event;
2023 if (!pmu->commit_txn(pmu))
2028 * Groups can be scheduled in as one unit only, so undo any
2029 * partial group before returning:
2030 * The events up to the failed event are scheduled out normally,
2031 * tstamp_stopped will be updated.
2033 * The failed events and the remaining siblings need to have
2034 * their timings updated as if they had gone thru event_sched_in()
2035 * and event_sched_out(). This is required to get consistent timings
2036 * across the group. This also takes care of the case where the group
2037 * could never be scheduled by ensuring tstamp_stopped is set to mark
2038 * the time the event was actually stopped, such that time delta
2039 * calculation in update_event_times() is correct.
2041 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2042 if (event == partial_group)
2046 event->tstamp_running += now - event->tstamp_stopped;
2047 event->tstamp_stopped = now;
2049 event_sched_out(event, cpuctx, ctx);
2052 event_sched_out(group_event, cpuctx, ctx);
2054 pmu->cancel_txn(pmu);
2056 perf_mux_hrtimer_restart(cpuctx);
2062 * Work out whether we can put this event group on the CPU now.
2064 static int group_can_go_on(struct perf_event *event,
2065 struct perf_cpu_context *cpuctx,
2069 * Groups consisting entirely of software events can always go on.
2071 if (event->group_flags & PERF_GROUP_SOFTWARE)
2074 * If an exclusive group is already on, no other hardware
2077 if (cpuctx->exclusive)
2080 * If this group is exclusive and there are already
2081 * events on the CPU, it can't go on.
2083 if (event->attr.exclusive && cpuctx->active_oncpu)
2086 * Otherwise, try to add it if all previous groups were able
2092 static void add_event_to_ctx(struct perf_event *event,
2093 struct perf_event_context *ctx)
2095 u64 tstamp = perf_event_time(event);
2097 list_add_event(event, ctx);
2098 perf_group_attach(event);
2099 event->tstamp_enabled = tstamp;
2100 event->tstamp_running = tstamp;
2101 event->tstamp_stopped = tstamp;
2104 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2105 struct perf_event_context *ctx);
2107 ctx_sched_in(struct perf_event_context *ctx,
2108 struct perf_cpu_context *cpuctx,
2109 enum event_type_t event_type,
2110 struct task_struct *task);
2112 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2113 struct perf_event_context *ctx,
2114 struct task_struct *task)
2116 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2118 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2119 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2121 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2124 static void ctx_resched(struct perf_cpu_context *cpuctx,
2125 struct perf_event_context *task_ctx)
2127 perf_pmu_disable(cpuctx->ctx.pmu);
2129 task_ctx_sched_out(cpuctx, task_ctx);
2130 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2131 perf_event_sched_in(cpuctx, task_ctx, current);
2132 perf_pmu_enable(cpuctx->ctx.pmu);
2136 * Cross CPU call to install and enable a performance event
2138 * Must be called with ctx->mutex held
2140 static int __perf_install_in_context(void *info)
2142 struct perf_event_context *ctx = info;
2143 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2144 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2146 raw_spin_lock(&cpuctx->ctx.lock);
2148 raw_spin_lock(&ctx->lock);
2150 * If we hit the 'wrong' task, we've since scheduled and
2151 * everything should be sorted, nothing to do!
2154 if (ctx->task != current)
2158 * If task_ctx is set, it had better be to us.
2160 WARN_ON_ONCE(cpuctx->task_ctx != ctx && cpuctx->task_ctx);
2161 } else if (task_ctx) {
2162 raw_spin_lock(&task_ctx->lock);
2165 ctx_resched(cpuctx, task_ctx);
2167 perf_ctx_unlock(cpuctx, task_ctx);
2173 * Attach a performance event to a context
2176 perf_install_in_context(struct perf_event_context *ctx,
2177 struct perf_event *event,
2180 struct task_struct *task = NULL;
2182 lockdep_assert_held(&ctx->mutex);
2185 if (event->cpu != -1)
2189 * Installing events is tricky because we cannot rely on ctx->is_active
2190 * to be set in case this is the nr_events 0 -> 1 transition.
2192 * So what we do is we add the event to the list here, which will allow
2193 * a future context switch to DTRT and then send a racy IPI. If the IPI
2194 * fails to hit the right task, this means a context switch must have
2195 * happened and that will have taken care of business.
2197 raw_spin_lock_irq(&ctx->lock);
2200 * Worse, we cannot even rely on the ctx actually existing anymore. If
2201 * between find_get_context() and perf_install_in_context() the task
2202 * went through perf_event_exit_task() its dead and we should not be
2203 * adding new events.
2205 if (task == TASK_TOMBSTONE) {
2206 raw_spin_unlock_irq(&ctx->lock);
2209 update_context_time(ctx);
2211 * Update cgrp time only if current cgrp matches event->cgrp.
2212 * Must be done before calling add_event_to_ctx().
2214 update_cgrp_time_from_event(event);
2215 add_event_to_ctx(event, ctx);
2216 raw_spin_unlock_irq(&ctx->lock);
2219 task_function_call(task, __perf_install_in_context, ctx);
2221 cpu_function_call(cpu, __perf_install_in_context, ctx);
2225 * Put a event into inactive state and update time fields.
2226 * Enabling the leader of a group effectively enables all
2227 * the group members that aren't explicitly disabled, so we
2228 * have to update their ->tstamp_enabled also.
2229 * Note: this works for group members as well as group leaders
2230 * since the non-leader members' sibling_lists will be empty.
2232 static void __perf_event_mark_enabled(struct perf_event *event)
2234 struct perf_event *sub;
2235 u64 tstamp = perf_event_time(event);
2237 event->state = PERF_EVENT_STATE_INACTIVE;
2238 event->tstamp_enabled = tstamp - event->total_time_enabled;
2239 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2240 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2241 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2246 * Cross CPU call to enable a performance event
2248 static void __perf_event_enable(struct perf_event *event,
2249 struct perf_cpu_context *cpuctx,
2250 struct perf_event_context *ctx,
2253 struct perf_event *leader = event->group_leader;
2254 struct perf_event_context *task_ctx;
2256 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2257 event->state <= PERF_EVENT_STATE_ERROR)
2260 update_context_time(ctx);
2261 __perf_event_mark_enabled(event);
2263 if (!ctx->is_active)
2266 if (!event_filter_match(event)) {
2267 if (is_cgroup_event(event)) {
2268 perf_cgroup_set_timestamp(current, ctx); // XXX ?
2269 perf_cgroup_defer_enabled(event);
2275 * If the event is in a group and isn't the group leader,
2276 * then don't put it on unless the group is on.
2278 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2281 task_ctx = cpuctx->task_ctx;
2283 WARN_ON_ONCE(task_ctx != ctx);
2285 ctx_resched(cpuctx, task_ctx);
2291 * If event->ctx is a cloned context, callers must make sure that
2292 * every task struct that event->ctx->task could possibly point to
2293 * remains valid. This condition is satisfied when called through
2294 * perf_event_for_each_child or perf_event_for_each as described
2295 * for perf_event_disable.
2297 static void _perf_event_enable(struct perf_event *event)
2299 struct perf_event_context *ctx = event->ctx;
2301 raw_spin_lock_irq(&ctx->lock);
2302 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2303 event->state < PERF_EVENT_STATE_ERROR) {
2304 raw_spin_unlock_irq(&ctx->lock);
2309 * If the event is in error state, clear that first.
2311 * That way, if we see the event in error state below, we know that it
2312 * has gone back into error state, as distinct from the task having
2313 * been scheduled away before the cross-call arrived.
2315 if (event->state == PERF_EVENT_STATE_ERROR)
2316 event->state = PERF_EVENT_STATE_OFF;
2317 raw_spin_unlock_irq(&ctx->lock);
2319 event_function_call(event, __perf_event_enable, NULL);
2323 * See perf_event_disable();
2325 void perf_event_enable(struct perf_event *event)
2327 struct perf_event_context *ctx;
2329 ctx = perf_event_ctx_lock(event);
2330 _perf_event_enable(event);
2331 perf_event_ctx_unlock(event, ctx);
2333 EXPORT_SYMBOL_GPL(perf_event_enable);
2335 static int _perf_event_refresh(struct perf_event *event, int refresh)
2338 * not supported on inherited events
2340 if (event->attr.inherit || !is_sampling_event(event))
2343 atomic_add(refresh, &event->event_limit);
2344 _perf_event_enable(event);
2350 * See perf_event_disable()
2352 int perf_event_refresh(struct perf_event *event, int refresh)
2354 struct perf_event_context *ctx;
2357 ctx = perf_event_ctx_lock(event);
2358 ret = _perf_event_refresh(event, refresh);
2359 perf_event_ctx_unlock(event, ctx);
2363 EXPORT_SYMBOL_GPL(perf_event_refresh);
2365 static void ctx_sched_out(struct perf_event_context *ctx,
2366 struct perf_cpu_context *cpuctx,
2367 enum event_type_t event_type)
2369 int is_active = ctx->is_active;
2370 struct perf_event *event;
2372 lockdep_assert_held(&ctx->lock);
2374 if (likely(!ctx->nr_events)) {
2376 * See __perf_remove_from_context().
2378 WARN_ON_ONCE(ctx->is_active);
2380 WARN_ON_ONCE(cpuctx->task_ctx);
2384 ctx->is_active &= ~event_type;
2386 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2387 if (!ctx->is_active)
2388 cpuctx->task_ctx = NULL;
2391 update_context_time(ctx);
2392 update_cgrp_time_from_cpuctx(cpuctx);
2393 if (!ctx->nr_active)
2396 perf_pmu_disable(ctx->pmu);
2397 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2398 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2399 group_sched_out(event, cpuctx, ctx);
2402 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2403 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2404 group_sched_out(event, cpuctx, ctx);
2406 perf_pmu_enable(ctx->pmu);
2410 * Test whether two contexts are equivalent, i.e. whether they have both been
2411 * cloned from the same version of the same context.
2413 * Equivalence is measured using a generation number in the context that is
2414 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2415 * and list_del_event().
2417 static int context_equiv(struct perf_event_context *ctx1,
2418 struct perf_event_context *ctx2)
2420 lockdep_assert_held(&ctx1->lock);
2421 lockdep_assert_held(&ctx2->lock);
2423 /* Pinning disables the swap optimization */
2424 if (ctx1->pin_count || ctx2->pin_count)
2427 /* If ctx1 is the parent of ctx2 */
2428 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2431 /* If ctx2 is the parent of ctx1 */
2432 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2436 * If ctx1 and ctx2 have the same parent; we flatten the parent
2437 * hierarchy, see perf_event_init_context().
2439 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2440 ctx1->parent_gen == ctx2->parent_gen)
2447 static void __perf_event_sync_stat(struct perf_event *event,
2448 struct perf_event *next_event)
2452 if (!event->attr.inherit_stat)
2456 * Update the event value, we cannot use perf_event_read()
2457 * because we're in the middle of a context switch and have IRQs
2458 * disabled, which upsets smp_call_function_single(), however
2459 * we know the event must be on the current CPU, therefore we
2460 * don't need to use it.
2462 switch (event->state) {
2463 case PERF_EVENT_STATE_ACTIVE:
2464 event->pmu->read(event);
2467 case PERF_EVENT_STATE_INACTIVE:
2468 update_event_times(event);
2476 * In order to keep per-task stats reliable we need to flip the event
2477 * values when we flip the contexts.
2479 value = local64_read(&next_event->count);
2480 value = local64_xchg(&event->count, value);
2481 local64_set(&next_event->count, value);
2483 swap(event->total_time_enabled, next_event->total_time_enabled);
2484 swap(event->total_time_running, next_event->total_time_running);
2487 * Since we swizzled the values, update the user visible data too.
2489 perf_event_update_userpage(event);
2490 perf_event_update_userpage(next_event);
2493 static void perf_event_sync_stat(struct perf_event_context *ctx,
2494 struct perf_event_context *next_ctx)
2496 struct perf_event *event, *next_event;
2501 update_context_time(ctx);
2503 event = list_first_entry(&ctx->event_list,
2504 struct perf_event, event_entry);
2506 next_event = list_first_entry(&next_ctx->event_list,
2507 struct perf_event, event_entry);
2509 while (&event->event_entry != &ctx->event_list &&
2510 &next_event->event_entry != &next_ctx->event_list) {
2512 __perf_event_sync_stat(event, next_event);
2514 event = list_next_entry(event, event_entry);
2515 next_event = list_next_entry(next_event, event_entry);
2519 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2520 struct task_struct *next)
2522 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2523 struct perf_event_context *next_ctx;
2524 struct perf_event_context *parent, *next_parent;
2525 struct perf_cpu_context *cpuctx;
2531 cpuctx = __get_cpu_context(ctx);
2532 if (!cpuctx->task_ctx)
2536 next_ctx = next->perf_event_ctxp[ctxn];
2540 parent = rcu_dereference(ctx->parent_ctx);
2541 next_parent = rcu_dereference(next_ctx->parent_ctx);
2543 /* If neither context have a parent context; they cannot be clones. */
2544 if (!parent && !next_parent)
2547 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2549 * Looks like the two contexts are clones, so we might be
2550 * able to optimize the context switch. We lock both
2551 * contexts and check that they are clones under the
2552 * lock (including re-checking that neither has been
2553 * uncloned in the meantime). It doesn't matter which
2554 * order we take the locks because no other cpu could
2555 * be trying to lock both of these tasks.
2557 raw_spin_lock(&ctx->lock);
2558 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2559 if (context_equiv(ctx, next_ctx)) {
2560 WRITE_ONCE(ctx->task, next);
2561 WRITE_ONCE(next_ctx->task, task);
2563 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2566 * RCU_INIT_POINTER here is safe because we've not
2567 * modified the ctx and the above modification of
2568 * ctx->task and ctx->task_ctx_data are immaterial
2569 * since those values are always verified under
2570 * ctx->lock which we're now holding.
2572 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2573 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2577 perf_event_sync_stat(ctx, next_ctx);
2579 raw_spin_unlock(&next_ctx->lock);
2580 raw_spin_unlock(&ctx->lock);
2586 raw_spin_lock(&ctx->lock);
2587 task_ctx_sched_out(cpuctx, ctx);
2588 raw_spin_unlock(&ctx->lock);
2592 void perf_sched_cb_dec(struct pmu *pmu)
2594 this_cpu_dec(perf_sched_cb_usages);
2597 void perf_sched_cb_inc(struct pmu *pmu)
2599 this_cpu_inc(perf_sched_cb_usages);
2603 * This function provides the context switch callback to the lower code
2604 * layer. It is invoked ONLY when the context switch callback is enabled.
2606 static void perf_pmu_sched_task(struct task_struct *prev,
2607 struct task_struct *next,
2610 struct perf_cpu_context *cpuctx;
2612 unsigned long flags;
2617 local_irq_save(flags);
2621 list_for_each_entry_rcu(pmu, &pmus, entry) {
2622 if (pmu->sched_task) {
2623 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2625 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2627 perf_pmu_disable(pmu);
2629 pmu->sched_task(cpuctx->task_ctx, sched_in);
2631 perf_pmu_enable(pmu);
2633 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2639 local_irq_restore(flags);
2642 static void perf_event_switch(struct task_struct *task,
2643 struct task_struct *next_prev, bool sched_in);
2645 #define for_each_task_context_nr(ctxn) \
2646 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2649 * Called from scheduler to remove the events of the current task,
2650 * with interrupts disabled.
2652 * We stop each event and update the event value in event->count.
2654 * This does not protect us against NMI, but disable()
2655 * sets the disabled bit in the control field of event _before_
2656 * accessing the event control register. If a NMI hits, then it will
2657 * not restart the event.
2659 void __perf_event_task_sched_out(struct task_struct *task,
2660 struct task_struct *next)
2664 if (__this_cpu_read(perf_sched_cb_usages))
2665 perf_pmu_sched_task(task, next, false);
2667 if (atomic_read(&nr_switch_events))
2668 perf_event_switch(task, next, false);
2670 for_each_task_context_nr(ctxn)
2671 perf_event_context_sched_out(task, ctxn, next);
2674 * if cgroup events exist on this CPU, then we need
2675 * to check if we have to switch out PMU state.
2676 * cgroup event are system-wide mode only
2678 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2679 perf_cgroup_sched_out(task, next);
2682 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2683 struct perf_event_context *ctx)
2685 if (!cpuctx->task_ctx)
2688 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2691 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2695 * Called with IRQs disabled
2697 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2698 enum event_type_t event_type)
2700 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2704 ctx_pinned_sched_in(struct perf_event_context *ctx,
2705 struct perf_cpu_context *cpuctx)
2707 struct perf_event *event;
2709 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2710 if (event->state <= PERF_EVENT_STATE_OFF)
2712 if (!event_filter_match(event))
2715 /* may need to reset tstamp_enabled */
2716 if (is_cgroup_event(event))
2717 perf_cgroup_mark_enabled(event, ctx);
2719 if (group_can_go_on(event, cpuctx, 1))
2720 group_sched_in(event, cpuctx, ctx);
2723 * If this pinned group hasn't been scheduled,
2724 * put it in error state.
2726 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2727 update_group_times(event);
2728 event->state = PERF_EVENT_STATE_ERROR;
2734 ctx_flexible_sched_in(struct perf_event_context *ctx,
2735 struct perf_cpu_context *cpuctx)
2737 struct perf_event *event;
2740 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2741 /* Ignore events in OFF or ERROR state */
2742 if (event->state <= PERF_EVENT_STATE_OFF)
2745 * Listen to the 'cpu' scheduling filter constraint
2748 if (!event_filter_match(event))
2751 /* may need to reset tstamp_enabled */
2752 if (is_cgroup_event(event))
2753 perf_cgroup_mark_enabled(event, ctx);
2755 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2756 if (group_sched_in(event, cpuctx, ctx))
2763 ctx_sched_in(struct perf_event_context *ctx,
2764 struct perf_cpu_context *cpuctx,
2765 enum event_type_t event_type,
2766 struct task_struct *task)
2768 int is_active = ctx->is_active;
2771 lockdep_assert_held(&ctx->lock);
2773 if (likely(!ctx->nr_events))
2776 ctx->is_active |= event_type;
2779 cpuctx->task_ctx = ctx;
2781 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2785 ctx->timestamp = now;
2786 perf_cgroup_set_timestamp(task, ctx);
2788 * First go through the list and put on any pinned groups
2789 * in order to give them the best chance of going on.
2791 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2792 ctx_pinned_sched_in(ctx, cpuctx);
2794 /* Then walk through the lower prio flexible groups */
2795 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2796 ctx_flexible_sched_in(ctx, cpuctx);
2799 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2800 enum event_type_t event_type,
2801 struct task_struct *task)
2803 struct perf_event_context *ctx = &cpuctx->ctx;
2805 ctx_sched_in(ctx, cpuctx, event_type, task);
2808 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2809 struct task_struct *task)
2811 struct perf_cpu_context *cpuctx;
2813 cpuctx = __get_cpu_context(ctx);
2814 if (cpuctx->task_ctx == ctx)
2817 perf_ctx_lock(cpuctx, ctx);
2818 perf_pmu_disable(ctx->pmu);
2820 * We want to keep the following priority order:
2821 * cpu pinned (that don't need to move), task pinned,
2822 * cpu flexible, task flexible.
2824 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2825 perf_event_sched_in(cpuctx, ctx, task);
2826 perf_pmu_enable(ctx->pmu);
2827 perf_ctx_unlock(cpuctx, ctx);
2831 * Called from scheduler to add the events of the current task
2832 * with interrupts disabled.
2834 * We restore the event value and then enable it.
2836 * This does not protect us against NMI, but enable()
2837 * sets the enabled bit in the control field of event _before_
2838 * accessing the event control register. If a NMI hits, then it will
2839 * keep the event running.
2841 void __perf_event_task_sched_in(struct task_struct *prev,
2842 struct task_struct *task)
2844 struct perf_event_context *ctx;
2848 * If cgroup events exist on this CPU, then we need to check if we have
2849 * to switch in PMU state; cgroup event are system-wide mode only.
2851 * Since cgroup events are CPU events, we must schedule these in before
2852 * we schedule in the task events.
2854 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2855 perf_cgroup_sched_in(prev, task);
2857 for_each_task_context_nr(ctxn) {
2858 ctx = task->perf_event_ctxp[ctxn];
2862 perf_event_context_sched_in(ctx, task);
2865 if (atomic_read(&nr_switch_events))
2866 perf_event_switch(task, prev, true);
2868 if (__this_cpu_read(perf_sched_cb_usages))
2869 perf_pmu_sched_task(prev, task, true);
2872 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2874 u64 frequency = event->attr.sample_freq;
2875 u64 sec = NSEC_PER_SEC;
2876 u64 divisor, dividend;
2878 int count_fls, nsec_fls, frequency_fls, sec_fls;
2880 count_fls = fls64(count);
2881 nsec_fls = fls64(nsec);
2882 frequency_fls = fls64(frequency);
2886 * We got @count in @nsec, with a target of sample_freq HZ
2887 * the target period becomes:
2890 * period = -------------------
2891 * @nsec * sample_freq
2896 * Reduce accuracy by one bit such that @a and @b converge
2897 * to a similar magnitude.
2899 #define REDUCE_FLS(a, b) \
2901 if (a##_fls > b##_fls) { \
2911 * Reduce accuracy until either term fits in a u64, then proceed with
2912 * the other, so that finally we can do a u64/u64 division.
2914 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2915 REDUCE_FLS(nsec, frequency);
2916 REDUCE_FLS(sec, count);
2919 if (count_fls + sec_fls > 64) {
2920 divisor = nsec * frequency;
2922 while (count_fls + sec_fls > 64) {
2923 REDUCE_FLS(count, sec);
2927 dividend = count * sec;
2929 dividend = count * sec;
2931 while (nsec_fls + frequency_fls > 64) {
2932 REDUCE_FLS(nsec, frequency);
2936 divisor = nsec * frequency;
2942 return div64_u64(dividend, divisor);
2945 static DEFINE_PER_CPU(int, perf_throttled_count);
2946 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2948 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2950 struct hw_perf_event *hwc = &event->hw;
2951 s64 period, sample_period;
2954 period = perf_calculate_period(event, nsec, count);
2956 delta = (s64)(period - hwc->sample_period);
2957 delta = (delta + 7) / 8; /* low pass filter */
2959 sample_period = hwc->sample_period + delta;
2964 hwc->sample_period = sample_period;
2966 if (local64_read(&hwc->period_left) > 8*sample_period) {
2968 event->pmu->stop(event, PERF_EF_UPDATE);
2970 local64_set(&hwc->period_left, 0);
2973 event->pmu->start(event, PERF_EF_RELOAD);
2978 * combine freq adjustment with unthrottling to avoid two passes over the
2979 * events. At the same time, make sure, having freq events does not change
2980 * the rate of unthrottling as that would introduce bias.
2982 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2985 struct perf_event *event;
2986 struct hw_perf_event *hwc;
2987 u64 now, period = TICK_NSEC;
2991 * only need to iterate over all events iff:
2992 * - context have events in frequency mode (needs freq adjust)
2993 * - there are events to unthrottle on this cpu
2995 if (!(ctx->nr_freq || needs_unthr))
2998 raw_spin_lock(&ctx->lock);
2999 perf_pmu_disable(ctx->pmu);
3001 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3002 if (event->state != PERF_EVENT_STATE_ACTIVE)
3005 if (!event_filter_match(event))
3008 perf_pmu_disable(event->pmu);
3012 if (hwc->interrupts == MAX_INTERRUPTS) {
3013 hwc->interrupts = 0;
3014 perf_log_throttle(event, 1);
3015 event->pmu->start(event, 0);
3018 if (!event->attr.freq || !event->attr.sample_freq)
3022 * stop the event and update event->count
3024 event->pmu->stop(event, PERF_EF_UPDATE);
3026 now = local64_read(&event->count);
3027 delta = now - hwc->freq_count_stamp;
3028 hwc->freq_count_stamp = now;
3032 * reload only if value has changed
3033 * we have stopped the event so tell that
3034 * to perf_adjust_period() to avoid stopping it
3038 perf_adjust_period(event, period, delta, false);
3040 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3042 perf_pmu_enable(event->pmu);
3045 perf_pmu_enable(ctx->pmu);
3046 raw_spin_unlock(&ctx->lock);
3050 * Round-robin a context's events:
3052 static void rotate_ctx(struct perf_event_context *ctx)
3055 * Rotate the first entry last of non-pinned groups. Rotation might be
3056 * disabled by the inheritance code.
3058 if (!ctx->rotate_disable)
3059 list_rotate_left(&ctx->flexible_groups);
3062 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3064 struct perf_event_context *ctx = NULL;
3067 if (cpuctx->ctx.nr_events) {
3068 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3072 ctx = cpuctx->task_ctx;
3073 if (ctx && ctx->nr_events) {
3074 if (ctx->nr_events != ctx->nr_active)
3081 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3082 perf_pmu_disable(cpuctx->ctx.pmu);
3084 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3086 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3088 rotate_ctx(&cpuctx->ctx);
3092 perf_event_sched_in(cpuctx, ctx, current);
3094 perf_pmu_enable(cpuctx->ctx.pmu);
3095 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3101 #ifdef CONFIG_NO_HZ_FULL
3102 bool perf_event_can_stop_tick(void)
3104 if (atomic_read(&nr_freq_events) ||
3105 __this_cpu_read(perf_throttled_count))
3112 void perf_event_task_tick(void)
3114 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3115 struct perf_event_context *ctx, *tmp;
3118 WARN_ON(!irqs_disabled());
3120 __this_cpu_inc(perf_throttled_seq);
3121 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3123 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3124 perf_adjust_freq_unthr_context(ctx, throttled);
3127 static int event_enable_on_exec(struct perf_event *event,
3128 struct perf_event_context *ctx)
3130 if (!event->attr.enable_on_exec)
3133 event->attr.enable_on_exec = 0;
3134 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3137 __perf_event_mark_enabled(event);
3143 * Enable all of a task's events that have been marked enable-on-exec.
3144 * This expects task == current.
3146 static void perf_event_enable_on_exec(int ctxn)
3148 struct perf_event_context *ctx, *clone_ctx = NULL;
3149 struct perf_cpu_context *cpuctx;
3150 struct perf_event *event;
3151 unsigned long flags;
3154 local_irq_save(flags);
3155 ctx = current->perf_event_ctxp[ctxn];
3156 if (!ctx || !ctx->nr_events)
3159 cpuctx = __get_cpu_context(ctx);
3160 perf_ctx_lock(cpuctx, ctx);
3161 list_for_each_entry(event, &ctx->event_list, event_entry)
3162 enabled |= event_enable_on_exec(event, ctx);
3165 * Unclone and reschedule this context if we enabled any event.
3168 clone_ctx = unclone_ctx(ctx);
3169 ctx_resched(cpuctx, ctx);
3171 perf_ctx_unlock(cpuctx, ctx);
3174 local_irq_restore(flags);
3180 void perf_event_exec(void)
3185 for_each_task_context_nr(ctxn)
3186 perf_event_enable_on_exec(ctxn);
3190 struct perf_read_data {
3191 struct perf_event *event;
3197 * Cross CPU call to read the hardware event
3199 static void __perf_event_read(void *info)
3201 struct perf_read_data *data = info;
3202 struct perf_event *sub, *event = data->event;
3203 struct perf_event_context *ctx = event->ctx;
3204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3205 struct pmu *pmu = event->pmu;
3208 * If this is a task context, we need to check whether it is
3209 * the current task context of this cpu. If not it has been
3210 * scheduled out before the smp call arrived. In that case
3211 * event->count would have been updated to a recent sample
3212 * when the event was scheduled out.
3214 if (ctx->task && cpuctx->task_ctx != ctx)
3217 raw_spin_lock(&ctx->lock);
3218 if (ctx->is_active) {
3219 update_context_time(ctx);
3220 update_cgrp_time_from_event(event);
3223 update_event_times(event);
3224 if (event->state != PERF_EVENT_STATE_ACTIVE)
3233 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3237 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3238 update_event_times(sub);
3239 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3241 * Use sibling's PMU rather than @event's since
3242 * sibling could be on different (eg: software) PMU.
3244 sub->pmu->read(sub);
3248 data->ret = pmu->commit_txn(pmu);
3251 raw_spin_unlock(&ctx->lock);
3254 static inline u64 perf_event_count(struct perf_event *event)
3256 if (event->pmu->count)
3257 return event->pmu->count(event);
3259 return __perf_event_count(event);
3263 * NMI-safe method to read a local event, that is an event that
3265 * - either for the current task, or for this CPU
3266 * - does not have inherit set, for inherited task events
3267 * will not be local and we cannot read them atomically
3268 * - must not have a pmu::count method
3270 u64 perf_event_read_local(struct perf_event *event)
3272 unsigned long flags;
3276 * Disabling interrupts avoids all counter scheduling (context
3277 * switches, timer based rotation and IPIs).
3279 local_irq_save(flags);
3281 /* If this is a per-task event, it must be for current */
3282 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3283 event->hw.target != current);
3285 /* If this is a per-CPU event, it must be for this CPU */
3286 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3287 event->cpu != smp_processor_id());
3290 * It must not be an event with inherit set, we cannot read
3291 * all child counters from atomic context.
3293 WARN_ON_ONCE(event->attr.inherit);
3296 * It must not have a pmu::count method, those are not
3299 WARN_ON_ONCE(event->pmu->count);
3302 * If the event is currently on this CPU, its either a per-task event,
3303 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3306 if (event->oncpu == smp_processor_id())
3307 event->pmu->read(event);
3309 val = local64_read(&event->count);
3310 local_irq_restore(flags);
3315 static int perf_event_read(struct perf_event *event, bool group)
3320 * If event is enabled and currently active on a CPU, update the
3321 * value in the event structure:
3323 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3324 struct perf_read_data data = {
3329 smp_call_function_single(event->oncpu,
3330 __perf_event_read, &data, 1);
3332 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3333 struct perf_event_context *ctx = event->ctx;
3334 unsigned long flags;
3336 raw_spin_lock_irqsave(&ctx->lock, flags);
3338 * may read while context is not active
3339 * (e.g., thread is blocked), in that case
3340 * we cannot update context time
3342 if (ctx->is_active) {
3343 update_context_time(ctx);
3344 update_cgrp_time_from_event(event);
3347 update_group_times(event);
3349 update_event_times(event);
3350 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3357 * Initialize the perf_event context in a task_struct:
3359 static void __perf_event_init_context(struct perf_event_context *ctx)
3361 raw_spin_lock_init(&ctx->lock);
3362 mutex_init(&ctx->mutex);
3363 INIT_LIST_HEAD(&ctx->active_ctx_list);
3364 INIT_LIST_HEAD(&ctx->pinned_groups);
3365 INIT_LIST_HEAD(&ctx->flexible_groups);
3366 INIT_LIST_HEAD(&ctx->event_list);
3367 atomic_set(&ctx->refcount, 1);
3368 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3371 static struct perf_event_context *
3372 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3374 struct perf_event_context *ctx;
3376 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3380 __perf_event_init_context(ctx);
3383 get_task_struct(task);
3390 static struct task_struct *
3391 find_lively_task_by_vpid(pid_t vpid)
3393 struct task_struct *task;
3400 task = find_task_by_vpid(vpid);
3402 get_task_struct(task);
3406 return ERR_PTR(-ESRCH);
3408 /* Reuse ptrace permission checks for now. */
3410 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3415 put_task_struct(task);
3416 return ERR_PTR(err);
3421 * Returns a matching context with refcount and pincount.
3423 static struct perf_event_context *
3424 find_get_context(struct pmu *pmu, struct task_struct *task,
3425 struct perf_event *event)
3427 struct perf_event_context *ctx, *clone_ctx = NULL;
3428 struct perf_cpu_context *cpuctx;
3429 void *task_ctx_data = NULL;
3430 unsigned long flags;
3432 int cpu = event->cpu;
3435 /* Must be root to operate on a CPU event: */
3436 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3437 return ERR_PTR(-EACCES);
3440 * We could be clever and allow to attach a event to an
3441 * offline CPU and activate it when the CPU comes up, but
3444 if (!cpu_online(cpu))
3445 return ERR_PTR(-ENODEV);
3447 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3456 ctxn = pmu->task_ctx_nr;
3460 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3461 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3462 if (!task_ctx_data) {
3469 ctx = perf_lock_task_context(task, ctxn, &flags);
3471 clone_ctx = unclone_ctx(ctx);
3474 if (task_ctx_data && !ctx->task_ctx_data) {
3475 ctx->task_ctx_data = task_ctx_data;
3476 task_ctx_data = NULL;
3478 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3483 ctx = alloc_perf_context(pmu, task);
3488 if (task_ctx_data) {
3489 ctx->task_ctx_data = task_ctx_data;
3490 task_ctx_data = NULL;
3494 mutex_lock(&task->perf_event_mutex);
3496 * If it has already passed perf_event_exit_task().
3497 * we must see PF_EXITING, it takes this mutex too.
3499 if (task->flags & PF_EXITING)
3501 else if (task->perf_event_ctxp[ctxn])
3506 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3508 mutex_unlock(&task->perf_event_mutex);
3510 if (unlikely(err)) {
3519 kfree(task_ctx_data);
3523 kfree(task_ctx_data);
3524 return ERR_PTR(err);
3527 static void perf_event_free_filter(struct perf_event *event);
3528 static void perf_event_free_bpf_prog(struct perf_event *event);
3530 static void free_event_rcu(struct rcu_head *head)
3532 struct perf_event *event;
3534 event = container_of(head, struct perf_event, rcu_head);
3536 put_pid_ns(event->ns);
3537 perf_event_free_filter(event);
3541 static void ring_buffer_attach(struct perf_event *event,
3542 struct ring_buffer *rb);
3544 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3549 if (is_cgroup_event(event))
3550 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3553 static void unaccount_event(struct perf_event *event)
3560 if (event->attach_state & PERF_ATTACH_TASK)
3562 if (event->attr.mmap || event->attr.mmap_data)
3563 atomic_dec(&nr_mmap_events);
3564 if (event->attr.comm)
3565 atomic_dec(&nr_comm_events);
3566 if (event->attr.task)
3567 atomic_dec(&nr_task_events);
3568 if (event->attr.freq)
3569 atomic_dec(&nr_freq_events);
3570 if (event->attr.context_switch) {
3572 atomic_dec(&nr_switch_events);
3574 if (is_cgroup_event(event))
3576 if (has_branch_stack(event))
3580 static_key_slow_dec_deferred(&perf_sched_events);
3582 unaccount_event_cpu(event, event->cpu);
3586 * The following implement mutual exclusion of events on "exclusive" pmus
3587 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3588 * at a time, so we disallow creating events that might conflict, namely:
3590 * 1) cpu-wide events in the presence of per-task events,
3591 * 2) per-task events in the presence of cpu-wide events,
3592 * 3) two matching events on the same context.
3594 * The former two cases are handled in the allocation path (perf_event_alloc(),
3595 * _free_event()), the latter -- before the first perf_install_in_context().
3597 static int exclusive_event_init(struct perf_event *event)
3599 struct pmu *pmu = event->pmu;
3601 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3605 * Prevent co-existence of per-task and cpu-wide events on the
3606 * same exclusive pmu.
3608 * Negative pmu::exclusive_cnt means there are cpu-wide
3609 * events on this "exclusive" pmu, positive means there are
3612 * Since this is called in perf_event_alloc() path, event::ctx
3613 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3614 * to mean "per-task event", because unlike other attach states it
3615 * never gets cleared.
3617 if (event->attach_state & PERF_ATTACH_TASK) {
3618 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3621 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3628 static void exclusive_event_destroy(struct perf_event *event)
3630 struct pmu *pmu = event->pmu;
3632 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3635 /* see comment in exclusive_event_init() */
3636 if (event->attach_state & PERF_ATTACH_TASK)
3637 atomic_dec(&pmu->exclusive_cnt);
3639 atomic_inc(&pmu->exclusive_cnt);
3642 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3644 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3645 (e1->cpu == e2->cpu ||
3652 /* Called under the same ctx::mutex as perf_install_in_context() */
3653 static bool exclusive_event_installable(struct perf_event *event,
3654 struct perf_event_context *ctx)
3656 struct perf_event *iter_event;
3657 struct pmu *pmu = event->pmu;
3659 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3662 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3663 if (exclusive_event_match(iter_event, event))
3670 static void _free_event(struct perf_event *event)
3672 irq_work_sync(&event->pending);
3674 unaccount_event(event);
3678 * Can happen when we close an event with re-directed output.
3680 * Since we have a 0 refcount, perf_mmap_close() will skip
3681 * over us; possibly making our ring_buffer_put() the last.
3683 mutex_lock(&event->mmap_mutex);
3684 ring_buffer_attach(event, NULL);
3685 mutex_unlock(&event->mmap_mutex);
3688 if (is_cgroup_event(event))
3689 perf_detach_cgroup(event);
3691 if (!event->parent) {
3692 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3693 put_callchain_buffers();
3696 perf_event_free_bpf_prog(event);
3699 event->destroy(event);
3702 put_ctx(event->ctx);
3705 exclusive_event_destroy(event);
3706 module_put(event->pmu->module);
3709 call_rcu(&event->rcu_head, free_event_rcu);
3713 * Used to free events which have a known refcount of 1, such as in error paths
3714 * where the event isn't exposed yet and inherited events.
3716 static void free_event(struct perf_event *event)
3718 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3719 "unexpected event refcount: %ld; ptr=%p\n",
3720 atomic_long_read(&event->refcount), event)) {
3721 /* leak to avoid use-after-free */
3729 * Remove user event from the owner task.
3731 static void perf_remove_from_owner(struct perf_event *event)
3733 struct task_struct *owner;
3736 owner = ACCESS_ONCE(event->owner);
3738 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3739 * !owner it means the list deletion is complete and we can indeed
3740 * free this event, otherwise we need to serialize on
3741 * owner->perf_event_mutex.
3743 smp_read_barrier_depends();
3746 * Since delayed_put_task_struct() also drops the last
3747 * task reference we can safely take a new reference
3748 * while holding the rcu_read_lock().
3750 get_task_struct(owner);
3756 * If we're here through perf_event_exit_task() we're already
3757 * holding ctx->mutex which would be an inversion wrt. the
3758 * normal lock order.
3760 * However we can safely take this lock because its the child
3763 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3766 * We have to re-check the event->owner field, if it is cleared
3767 * we raced with perf_event_exit_task(), acquiring the mutex
3768 * ensured they're done, and we can proceed with freeing the
3772 list_del_init(&event->owner_entry);
3773 mutex_unlock(&owner->perf_event_mutex);
3774 put_task_struct(owner);
3778 static void put_event(struct perf_event *event)
3780 struct perf_event_context *ctx;
3782 if (!atomic_long_dec_and_test(&event->refcount))
3785 if (!is_kernel_event(event))
3786 perf_remove_from_owner(event);
3789 * There are two ways this annotation is useful:
3791 * 1) there is a lock recursion from perf_event_exit_task
3792 * see the comment there.
3794 * 2) there is a lock-inversion with mmap_sem through
3795 * perf_read_group(), which takes faults while
3796 * holding ctx->mutex, however this is called after
3797 * the last filedesc died, so there is no possibility
3798 * to trigger the AB-BA case.
3800 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3801 WARN_ON_ONCE(ctx->parent_ctx);
3802 perf_remove_from_context(event, true);
3803 perf_event_ctx_unlock(event, ctx);
3808 int perf_event_release_kernel(struct perf_event *event)
3813 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3816 * Called when the last reference to the file is gone.
3818 static int perf_release(struct inode *inode, struct file *file)
3820 put_event(file->private_data);
3825 * Remove all orphanes events from the context.
3827 static void orphans_remove_work(struct work_struct *work)
3829 struct perf_event_context *ctx;
3830 struct perf_event *event, *tmp;
3832 ctx = container_of(work, struct perf_event_context,
3833 orphans_remove.work);
3835 mutex_lock(&ctx->mutex);
3836 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3837 struct perf_event *parent_event = event->parent;
3839 if (!is_orphaned_child(event))
3842 perf_remove_from_context(event, true);
3844 mutex_lock(&parent_event->child_mutex);
3845 list_del_init(&event->child_list);
3846 mutex_unlock(&parent_event->child_mutex);
3849 put_event(parent_event);
3852 raw_spin_lock_irq(&ctx->lock);
3853 ctx->orphans_remove_sched = false;
3854 raw_spin_unlock_irq(&ctx->lock);
3855 mutex_unlock(&ctx->mutex);
3860 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3862 struct perf_event *child;
3868 mutex_lock(&event->child_mutex);
3870 (void)perf_event_read(event, false);
3871 total += perf_event_count(event);
3873 *enabled += event->total_time_enabled +
3874 atomic64_read(&event->child_total_time_enabled);
3875 *running += event->total_time_running +
3876 atomic64_read(&event->child_total_time_running);
3878 list_for_each_entry(child, &event->child_list, child_list) {
3879 (void)perf_event_read(child, false);
3880 total += perf_event_count(child);
3881 *enabled += child->total_time_enabled;
3882 *running += child->total_time_running;
3884 mutex_unlock(&event->child_mutex);
3888 EXPORT_SYMBOL_GPL(perf_event_read_value);
3890 static int __perf_read_group_add(struct perf_event *leader,
3891 u64 read_format, u64 *values)
3893 struct perf_event *sub;
3894 int n = 1; /* skip @nr */
3897 ret = perf_event_read(leader, true);
3902 * Since we co-schedule groups, {enabled,running} times of siblings
3903 * will be identical to those of the leader, so we only publish one
3906 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3907 values[n++] += leader->total_time_enabled +
3908 atomic64_read(&leader->child_total_time_enabled);
3911 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3912 values[n++] += leader->total_time_running +
3913 atomic64_read(&leader->child_total_time_running);
3917 * Write {count,id} tuples for every sibling.
3919 values[n++] += perf_event_count(leader);
3920 if (read_format & PERF_FORMAT_ID)
3921 values[n++] = primary_event_id(leader);
3923 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3924 values[n++] += perf_event_count(sub);
3925 if (read_format & PERF_FORMAT_ID)
3926 values[n++] = primary_event_id(sub);
3932 static int perf_read_group(struct perf_event *event,
3933 u64 read_format, char __user *buf)
3935 struct perf_event *leader = event->group_leader, *child;
3936 struct perf_event_context *ctx = leader->ctx;
3940 lockdep_assert_held(&ctx->mutex);
3942 values = kzalloc(event->read_size, GFP_KERNEL);
3946 values[0] = 1 + leader->nr_siblings;
3949 * By locking the child_mutex of the leader we effectively
3950 * lock the child list of all siblings.. XXX explain how.
3952 mutex_lock(&leader->child_mutex);
3954 ret = __perf_read_group_add(leader, read_format, values);
3958 list_for_each_entry(child, &leader->child_list, child_list) {
3959 ret = __perf_read_group_add(child, read_format, values);
3964 mutex_unlock(&leader->child_mutex);
3966 ret = event->read_size;
3967 if (copy_to_user(buf, values, event->read_size))
3972 mutex_unlock(&leader->child_mutex);
3978 static int perf_read_one(struct perf_event *event,
3979 u64 read_format, char __user *buf)
3981 u64 enabled, running;
3985 values[n++] = perf_event_read_value(event, &enabled, &running);
3986 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3987 values[n++] = enabled;
3988 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3989 values[n++] = running;
3990 if (read_format & PERF_FORMAT_ID)
3991 values[n++] = primary_event_id(event);
3993 if (copy_to_user(buf, values, n * sizeof(u64)))
3996 return n * sizeof(u64);
3999 static bool is_event_hup(struct perf_event *event)
4003 if (event->state != PERF_EVENT_STATE_EXIT)
4006 mutex_lock(&event->child_mutex);
4007 no_children = list_empty(&event->child_list);
4008 mutex_unlock(&event->child_mutex);
4013 * Read the performance event - simple non blocking version for now
4016 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4018 u64 read_format = event->attr.read_format;
4022 * Return end-of-file for a read on a event that is in
4023 * error state (i.e. because it was pinned but it couldn't be
4024 * scheduled on to the CPU at some point).
4026 if (event->state == PERF_EVENT_STATE_ERROR)
4029 if (count < event->read_size)
4032 WARN_ON_ONCE(event->ctx->parent_ctx);
4033 if (read_format & PERF_FORMAT_GROUP)
4034 ret = perf_read_group(event, read_format, buf);
4036 ret = perf_read_one(event, read_format, buf);
4042 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4044 struct perf_event *event = file->private_data;
4045 struct perf_event_context *ctx;
4048 ctx = perf_event_ctx_lock(event);
4049 ret = __perf_read(event, buf, count);
4050 perf_event_ctx_unlock(event, ctx);
4055 static unsigned int perf_poll(struct file *file, poll_table *wait)
4057 struct perf_event *event = file->private_data;
4058 struct ring_buffer *rb;
4059 unsigned int events = POLLHUP;
4061 poll_wait(file, &event->waitq, wait);
4063 if (is_event_hup(event))
4067 * Pin the event->rb by taking event->mmap_mutex; otherwise
4068 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4070 mutex_lock(&event->mmap_mutex);
4073 events = atomic_xchg(&rb->poll, 0);
4074 mutex_unlock(&event->mmap_mutex);
4078 static void _perf_event_reset(struct perf_event *event)
4080 (void)perf_event_read(event, false);
4081 local64_set(&event->count, 0);
4082 perf_event_update_userpage(event);
4086 * Holding the top-level event's child_mutex means that any
4087 * descendant process that has inherited this event will block
4088 * in sync_child_event if it goes to exit, thus satisfying the
4089 * task existence requirements of perf_event_enable/disable.
4091 static void perf_event_for_each_child(struct perf_event *event,
4092 void (*func)(struct perf_event *))
4094 struct perf_event *child;
4096 WARN_ON_ONCE(event->ctx->parent_ctx);
4098 mutex_lock(&event->child_mutex);
4100 list_for_each_entry(child, &event->child_list, child_list)
4102 mutex_unlock(&event->child_mutex);
4105 static void perf_event_for_each(struct perf_event *event,
4106 void (*func)(struct perf_event *))
4108 struct perf_event_context *ctx = event->ctx;
4109 struct perf_event *sibling;
4111 lockdep_assert_held(&ctx->mutex);
4113 event = event->group_leader;
4115 perf_event_for_each_child(event, func);
4116 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4117 perf_event_for_each_child(sibling, func);
4120 static void __perf_event_period(struct perf_event *event,
4121 struct perf_cpu_context *cpuctx,
4122 struct perf_event_context *ctx,
4125 u64 value = *((u64 *)info);
4128 if (event->attr.freq) {
4129 event->attr.sample_freq = value;
4131 event->attr.sample_period = value;
4132 event->hw.sample_period = value;
4135 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4137 perf_pmu_disable(ctx->pmu);
4138 event->pmu->stop(event, PERF_EF_UPDATE);
4141 local64_set(&event->hw.period_left, 0);
4144 event->pmu->start(event, PERF_EF_RELOAD);
4145 perf_pmu_enable(ctx->pmu);
4149 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4153 if (!is_sampling_event(event))
4156 if (copy_from_user(&value, arg, sizeof(value)))
4162 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4165 event_function_call(event, __perf_event_period, &value);
4170 static const struct file_operations perf_fops;
4172 static inline int perf_fget_light(int fd, struct fd *p)
4174 struct fd f = fdget(fd);
4178 if (f.file->f_op != &perf_fops) {
4186 static int perf_event_set_output(struct perf_event *event,
4187 struct perf_event *output_event);
4188 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4189 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4191 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4193 void (*func)(struct perf_event *);
4197 case PERF_EVENT_IOC_ENABLE:
4198 func = _perf_event_enable;
4200 case PERF_EVENT_IOC_DISABLE:
4201 func = _perf_event_disable;
4203 case PERF_EVENT_IOC_RESET:
4204 func = _perf_event_reset;
4207 case PERF_EVENT_IOC_REFRESH:
4208 return _perf_event_refresh(event, arg);
4210 case PERF_EVENT_IOC_PERIOD:
4211 return perf_event_period(event, (u64 __user *)arg);
4213 case PERF_EVENT_IOC_ID:
4215 u64 id = primary_event_id(event);
4217 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4222 case PERF_EVENT_IOC_SET_OUTPUT:
4226 struct perf_event *output_event;
4228 ret = perf_fget_light(arg, &output);
4231 output_event = output.file->private_data;
4232 ret = perf_event_set_output(event, output_event);
4235 ret = perf_event_set_output(event, NULL);
4240 case PERF_EVENT_IOC_SET_FILTER:
4241 return perf_event_set_filter(event, (void __user *)arg);
4243 case PERF_EVENT_IOC_SET_BPF:
4244 return perf_event_set_bpf_prog(event, arg);
4250 if (flags & PERF_IOC_FLAG_GROUP)
4251 perf_event_for_each(event, func);
4253 perf_event_for_each_child(event, func);
4258 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4260 struct perf_event *event = file->private_data;
4261 struct perf_event_context *ctx;
4264 ctx = perf_event_ctx_lock(event);
4265 ret = _perf_ioctl(event, cmd, arg);
4266 perf_event_ctx_unlock(event, ctx);
4271 #ifdef CONFIG_COMPAT
4272 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4275 switch (_IOC_NR(cmd)) {
4276 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4277 case _IOC_NR(PERF_EVENT_IOC_ID):
4278 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4279 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4280 cmd &= ~IOCSIZE_MASK;
4281 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4285 return perf_ioctl(file, cmd, arg);
4288 # define perf_compat_ioctl NULL
4291 int perf_event_task_enable(void)
4293 struct perf_event_context *ctx;
4294 struct perf_event *event;
4296 mutex_lock(¤t->perf_event_mutex);
4297 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4298 ctx = perf_event_ctx_lock(event);
4299 perf_event_for_each_child(event, _perf_event_enable);
4300 perf_event_ctx_unlock(event, ctx);
4302 mutex_unlock(¤t->perf_event_mutex);
4307 int perf_event_task_disable(void)
4309 struct perf_event_context *ctx;
4310 struct perf_event *event;
4312 mutex_lock(¤t->perf_event_mutex);
4313 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4314 ctx = perf_event_ctx_lock(event);
4315 perf_event_for_each_child(event, _perf_event_disable);
4316 perf_event_ctx_unlock(event, ctx);
4318 mutex_unlock(¤t->perf_event_mutex);
4323 static int perf_event_index(struct perf_event *event)
4325 if (event->hw.state & PERF_HES_STOPPED)
4328 if (event->state != PERF_EVENT_STATE_ACTIVE)
4331 return event->pmu->event_idx(event);
4334 static void calc_timer_values(struct perf_event *event,
4341 *now = perf_clock();
4342 ctx_time = event->shadow_ctx_time + *now;
4343 *enabled = ctx_time - event->tstamp_enabled;
4344 *running = ctx_time - event->tstamp_running;
4347 static void perf_event_init_userpage(struct perf_event *event)
4349 struct perf_event_mmap_page *userpg;
4350 struct ring_buffer *rb;
4353 rb = rcu_dereference(event->rb);
4357 userpg = rb->user_page;
4359 /* Allow new userspace to detect that bit 0 is deprecated */
4360 userpg->cap_bit0_is_deprecated = 1;
4361 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4362 userpg->data_offset = PAGE_SIZE;
4363 userpg->data_size = perf_data_size(rb);
4369 void __weak arch_perf_update_userpage(
4370 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4375 * Callers need to ensure there can be no nesting of this function, otherwise
4376 * the seqlock logic goes bad. We can not serialize this because the arch
4377 * code calls this from NMI context.
4379 void perf_event_update_userpage(struct perf_event *event)
4381 struct perf_event_mmap_page *userpg;
4382 struct ring_buffer *rb;
4383 u64 enabled, running, now;
4386 rb = rcu_dereference(event->rb);
4391 * compute total_time_enabled, total_time_running
4392 * based on snapshot values taken when the event
4393 * was last scheduled in.
4395 * we cannot simply called update_context_time()
4396 * because of locking issue as we can be called in
4399 calc_timer_values(event, &now, &enabled, &running);
4401 userpg = rb->user_page;
4403 * Disable preemption so as to not let the corresponding user-space
4404 * spin too long if we get preempted.
4409 userpg->index = perf_event_index(event);
4410 userpg->offset = perf_event_count(event);
4412 userpg->offset -= local64_read(&event->hw.prev_count);
4414 userpg->time_enabled = enabled +
4415 atomic64_read(&event->child_total_time_enabled);
4417 userpg->time_running = running +
4418 atomic64_read(&event->child_total_time_running);
4420 arch_perf_update_userpage(event, userpg, now);
4429 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4431 struct perf_event *event = vma->vm_file->private_data;
4432 struct ring_buffer *rb;
4433 int ret = VM_FAULT_SIGBUS;
4435 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4436 if (vmf->pgoff == 0)
4442 rb = rcu_dereference(event->rb);
4446 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4449 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4453 get_page(vmf->page);
4454 vmf->page->mapping = vma->vm_file->f_mapping;
4455 vmf->page->index = vmf->pgoff;
4464 static void ring_buffer_attach(struct perf_event *event,
4465 struct ring_buffer *rb)
4467 struct ring_buffer *old_rb = NULL;
4468 unsigned long flags;
4472 * Should be impossible, we set this when removing
4473 * event->rb_entry and wait/clear when adding event->rb_entry.
4475 WARN_ON_ONCE(event->rcu_pending);
4478 spin_lock_irqsave(&old_rb->event_lock, flags);
4479 list_del_rcu(&event->rb_entry);
4480 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4482 event->rcu_batches = get_state_synchronize_rcu();
4483 event->rcu_pending = 1;
4487 if (event->rcu_pending) {
4488 cond_synchronize_rcu(event->rcu_batches);
4489 event->rcu_pending = 0;
4492 spin_lock_irqsave(&rb->event_lock, flags);
4493 list_add_rcu(&event->rb_entry, &rb->event_list);
4494 spin_unlock_irqrestore(&rb->event_lock, flags);
4497 rcu_assign_pointer(event->rb, rb);
4500 ring_buffer_put(old_rb);
4502 * Since we detached before setting the new rb, so that we
4503 * could attach the new rb, we could have missed a wakeup.
4506 wake_up_all(&event->waitq);
4510 static void ring_buffer_wakeup(struct perf_event *event)
4512 struct ring_buffer *rb;
4515 rb = rcu_dereference(event->rb);
4517 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4518 wake_up_all(&event->waitq);
4523 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4525 struct ring_buffer *rb;
4528 rb = rcu_dereference(event->rb);
4530 if (!atomic_inc_not_zero(&rb->refcount))
4538 void ring_buffer_put(struct ring_buffer *rb)
4540 if (!atomic_dec_and_test(&rb->refcount))
4543 WARN_ON_ONCE(!list_empty(&rb->event_list));
4545 call_rcu(&rb->rcu_head, rb_free_rcu);
4548 static void perf_mmap_open(struct vm_area_struct *vma)
4550 struct perf_event *event = vma->vm_file->private_data;
4552 atomic_inc(&event->mmap_count);
4553 atomic_inc(&event->rb->mmap_count);
4556 atomic_inc(&event->rb->aux_mmap_count);
4558 if (event->pmu->event_mapped)
4559 event->pmu->event_mapped(event);
4563 * A buffer can be mmap()ed multiple times; either directly through the same
4564 * event, or through other events by use of perf_event_set_output().
4566 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4567 * the buffer here, where we still have a VM context. This means we need
4568 * to detach all events redirecting to us.
4570 static void perf_mmap_close(struct vm_area_struct *vma)
4572 struct perf_event *event = vma->vm_file->private_data;
4574 struct ring_buffer *rb = ring_buffer_get(event);
4575 struct user_struct *mmap_user = rb->mmap_user;
4576 int mmap_locked = rb->mmap_locked;
4577 unsigned long size = perf_data_size(rb);
4579 if (event->pmu->event_unmapped)
4580 event->pmu->event_unmapped(event);
4583 * rb->aux_mmap_count will always drop before rb->mmap_count and
4584 * event->mmap_count, so it is ok to use event->mmap_mutex to
4585 * serialize with perf_mmap here.
4587 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4588 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4589 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4590 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4593 mutex_unlock(&event->mmap_mutex);
4596 atomic_dec(&rb->mmap_count);
4598 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4601 ring_buffer_attach(event, NULL);
4602 mutex_unlock(&event->mmap_mutex);
4604 /* If there's still other mmap()s of this buffer, we're done. */
4605 if (atomic_read(&rb->mmap_count))
4609 * No other mmap()s, detach from all other events that might redirect
4610 * into the now unreachable buffer. Somewhat complicated by the
4611 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4615 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4616 if (!atomic_long_inc_not_zero(&event->refcount)) {
4618 * This event is en-route to free_event() which will
4619 * detach it and remove it from the list.
4625 mutex_lock(&event->mmap_mutex);
4627 * Check we didn't race with perf_event_set_output() which can
4628 * swizzle the rb from under us while we were waiting to
4629 * acquire mmap_mutex.
4631 * If we find a different rb; ignore this event, a next
4632 * iteration will no longer find it on the list. We have to
4633 * still restart the iteration to make sure we're not now
4634 * iterating the wrong list.
4636 if (event->rb == rb)
4637 ring_buffer_attach(event, NULL);
4639 mutex_unlock(&event->mmap_mutex);
4643 * Restart the iteration; either we're on the wrong list or
4644 * destroyed its integrity by doing a deletion.
4651 * It could be there's still a few 0-ref events on the list; they'll
4652 * get cleaned up by free_event() -- they'll also still have their
4653 * ref on the rb and will free it whenever they are done with it.
4655 * Aside from that, this buffer is 'fully' detached and unmapped,
4656 * undo the VM accounting.
4659 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4660 vma->vm_mm->pinned_vm -= mmap_locked;
4661 free_uid(mmap_user);
4664 ring_buffer_put(rb); /* could be last */
4667 static const struct vm_operations_struct perf_mmap_vmops = {
4668 .open = perf_mmap_open,
4669 .close = perf_mmap_close, /* non mergable */
4670 .fault = perf_mmap_fault,
4671 .page_mkwrite = perf_mmap_fault,
4674 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4676 struct perf_event *event = file->private_data;
4677 unsigned long user_locked, user_lock_limit;
4678 struct user_struct *user = current_user();
4679 unsigned long locked, lock_limit;
4680 struct ring_buffer *rb = NULL;
4681 unsigned long vma_size;
4682 unsigned long nr_pages;
4683 long user_extra = 0, extra = 0;
4684 int ret = 0, flags = 0;
4687 * Don't allow mmap() of inherited per-task counters. This would
4688 * create a performance issue due to all children writing to the
4691 if (event->cpu == -1 && event->attr.inherit)
4694 if (!(vma->vm_flags & VM_SHARED))
4697 vma_size = vma->vm_end - vma->vm_start;
4699 if (vma->vm_pgoff == 0) {
4700 nr_pages = (vma_size / PAGE_SIZE) - 1;
4703 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4704 * mapped, all subsequent mappings should have the same size
4705 * and offset. Must be above the normal perf buffer.
4707 u64 aux_offset, aux_size;
4712 nr_pages = vma_size / PAGE_SIZE;
4714 mutex_lock(&event->mmap_mutex);
4721 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4722 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4724 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4727 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4730 /* already mapped with a different offset */
4731 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4734 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4737 /* already mapped with a different size */
4738 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4741 if (!is_power_of_2(nr_pages))
4744 if (!atomic_inc_not_zero(&rb->mmap_count))
4747 if (rb_has_aux(rb)) {
4748 atomic_inc(&rb->aux_mmap_count);
4753 atomic_set(&rb->aux_mmap_count, 1);
4754 user_extra = nr_pages;
4760 * If we have rb pages ensure they're a power-of-two number, so we
4761 * can do bitmasks instead of modulo.
4763 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4766 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4769 WARN_ON_ONCE(event->ctx->parent_ctx);
4771 mutex_lock(&event->mmap_mutex);
4773 if (event->rb->nr_pages != nr_pages) {
4778 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4780 * Raced against perf_mmap_close() through
4781 * perf_event_set_output(). Try again, hope for better
4784 mutex_unlock(&event->mmap_mutex);
4791 user_extra = nr_pages + 1;
4794 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4797 * Increase the limit linearly with more CPUs:
4799 user_lock_limit *= num_online_cpus();
4801 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4803 if (user_locked > user_lock_limit)
4804 extra = user_locked - user_lock_limit;
4806 lock_limit = rlimit(RLIMIT_MEMLOCK);
4807 lock_limit >>= PAGE_SHIFT;
4808 locked = vma->vm_mm->pinned_vm + extra;
4810 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4811 !capable(CAP_IPC_LOCK)) {
4816 WARN_ON(!rb && event->rb);
4818 if (vma->vm_flags & VM_WRITE)
4819 flags |= RING_BUFFER_WRITABLE;
4822 rb = rb_alloc(nr_pages,
4823 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4831 atomic_set(&rb->mmap_count, 1);
4832 rb->mmap_user = get_current_user();
4833 rb->mmap_locked = extra;
4835 ring_buffer_attach(event, rb);
4837 perf_event_init_userpage(event);
4838 perf_event_update_userpage(event);
4840 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4841 event->attr.aux_watermark, flags);
4843 rb->aux_mmap_locked = extra;
4848 atomic_long_add(user_extra, &user->locked_vm);
4849 vma->vm_mm->pinned_vm += extra;
4851 atomic_inc(&event->mmap_count);
4853 atomic_dec(&rb->mmap_count);
4856 mutex_unlock(&event->mmap_mutex);
4859 * Since pinned accounting is per vm we cannot allow fork() to copy our
4862 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4863 vma->vm_ops = &perf_mmap_vmops;
4865 if (event->pmu->event_mapped)
4866 event->pmu->event_mapped(event);
4871 static int perf_fasync(int fd, struct file *filp, int on)
4873 struct inode *inode = file_inode(filp);
4874 struct perf_event *event = filp->private_data;
4877 mutex_lock(&inode->i_mutex);
4878 retval = fasync_helper(fd, filp, on, &event->fasync);
4879 mutex_unlock(&inode->i_mutex);
4887 static const struct file_operations perf_fops = {
4888 .llseek = no_llseek,
4889 .release = perf_release,
4892 .unlocked_ioctl = perf_ioctl,
4893 .compat_ioctl = perf_compat_ioctl,
4895 .fasync = perf_fasync,
4901 * If there's data, ensure we set the poll() state and publish everything
4902 * to user-space before waking everybody up.
4905 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4907 /* only the parent has fasync state */
4909 event = event->parent;
4910 return &event->fasync;
4913 void perf_event_wakeup(struct perf_event *event)
4915 ring_buffer_wakeup(event);
4917 if (event->pending_kill) {
4918 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4919 event->pending_kill = 0;
4923 static void perf_pending_event(struct irq_work *entry)
4925 struct perf_event *event = container_of(entry,
4926 struct perf_event, pending);
4929 rctx = perf_swevent_get_recursion_context();
4931 * If we 'fail' here, that's OK, it means recursion is already disabled
4932 * and we won't recurse 'further'.
4935 if (event->pending_disable) {
4936 event->pending_disable = 0;
4937 perf_event_disable_local(event);
4940 if (event->pending_wakeup) {
4941 event->pending_wakeup = 0;
4942 perf_event_wakeup(event);
4946 perf_swevent_put_recursion_context(rctx);
4950 * We assume there is only KVM supporting the callbacks.
4951 * Later on, we might change it to a list if there is
4952 * another virtualization implementation supporting the callbacks.
4954 struct perf_guest_info_callbacks *perf_guest_cbs;
4956 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4958 perf_guest_cbs = cbs;
4961 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4963 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4965 perf_guest_cbs = NULL;
4968 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4971 perf_output_sample_regs(struct perf_output_handle *handle,
4972 struct pt_regs *regs, u64 mask)
4976 for_each_set_bit(bit, (const unsigned long *) &mask,
4977 sizeof(mask) * BITS_PER_BYTE) {
4980 val = perf_reg_value(regs, bit);
4981 perf_output_put(handle, val);
4985 static void perf_sample_regs_user(struct perf_regs *regs_user,
4986 struct pt_regs *regs,
4987 struct pt_regs *regs_user_copy)
4989 if (user_mode(regs)) {
4990 regs_user->abi = perf_reg_abi(current);
4991 regs_user->regs = regs;
4992 } else if (current->mm) {
4993 perf_get_regs_user(regs_user, regs, regs_user_copy);
4995 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4996 regs_user->regs = NULL;
5000 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5001 struct pt_regs *regs)
5003 regs_intr->regs = regs;
5004 regs_intr->abi = perf_reg_abi(current);
5009 * Get remaining task size from user stack pointer.
5011 * It'd be better to take stack vma map and limit this more
5012 * precisly, but there's no way to get it safely under interrupt,
5013 * so using TASK_SIZE as limit.
5015 static u64 perf_ustack_task_size(struct pt_regs *regs)
5017 unsigned long addr = perf_user_stack_pointer(regs);
5019 if (!addr || addr >= TASK_SIZE)
5022 return TASK_SIZE - addr;
5026 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5027 struct pt_regs *regs)
5031 /* No regs, no stack pointer, no dump. */
5036 * Check if we fit in with the requested stack size into the:
5038 * If we don't, we limit the size to the TASK_SIZE.
5040 * - remaining sample size
5041 * If we don't, we customize the stack size to
5042 * fit in to the remaining sample size.
5045 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5046 stack_size = min(stack_size, (u16) task_size);
5048 /* Current header size plus static size and dynamic size. */
5049 header_size += 2 * sizeof(u64);
5051 /* Do we fit in with the current stack dump size? */
5052 if ((u16) (header_size + stack_size) < header_size) {
5054 * If we overflow the maximum size for the sample,
5055 * we customize the stack dump size to fit in.
5057 stack_size = USHRT_MAX - header_size - sizeof(u64);
5058 stack_size = round_up(stack_size, sizeof(u64));
5065 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5066 struct pt_regs *regs)
5068 /* Case of a kernel thread, nothing to dump */
5071 perf_output_put(handle, size);
5080 * - the size requested by user or the best one we can fit
5081 * in to the sample max size
5083 * - user stack dump data
5085 * - the actual dumped size
5089 perf_output_put(handle, dump_size);
5092 sp = perf_user_stack_pointer(regs);
5093 rem = __output_copy_user(handle, (void *) sp, dump_size);
5094 dyn_size = dump_size - rem;
5096 perf_output_skip(handle, rem);
5099 perf_output_put(handle, dyn_size);
5103 static void __perf_event_header__init_id(struct perf_event_header *header,
5104 struct perf_sample_data *data,
5105 struct perf_event *event)
5107 u64 sample_type = event->attr.sample_type;
5109 data->type = sample_type;
5110 header->size += event->id_header_size;
5112 if (sample_type & PERF_SAMPLE_TID) {
5113 /* namespace issues */
5114 data->tid_entry.pid = perf_event_pid(event, current);
5115 data->tid_entry.tid = perf_event_tid(event, current);
5118 if (sample_type & PERF_SAMPLE_TIME)
5119 data->time = perf_event_clock(event);
5121 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5122 data->id = primary_event_id(event);
5124 if (sample_type & PERF_SAMPLE_STREAM_ID)
5125 data->stream_id = event->id;
5127 if (sample_type & PERF_SAMPLE_CPU) {
5128 data->cpu_entry.cpu = raw_smp_processor_id();
5129 data->cpu_entry.reserved = 0;
5133 void perf_event_header__init_id(struct perf_event_header *header,
5134 struct perf_sample_data *data,
5135 struct perf_event *event)
5137 if (event->attr.sample_id_all)
5138 __perf_event_header__init_id(header, data, event);
5141 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5142 struct perf_sample_data *data)
5144 u64 sample_type = data->type;
5146 if (sample_type & PERF_SAMPLE_TID)
5147 perf_output_put(handle, data->tid_entry);
5149 if (sample_type & PERF_SAMPLE_TIME)
5150 perf_output_put(handle, data->time);
5152 if (sample_type & PERF_SAMPLE_ID)
5153 perf_output_put(handle, data->id);
5155 if (sample_type & PERF_SAMPLE_STREAM_ID)
5156 perf_output_put(handle, data->stream_id);
5158 if (sample_type & PERF_SAMPLE_CPU)
5159 perf_output_put(handle, data->cpu_entry);
5161 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5162 perf_output_put(handle, data->id);
5165 void perf_event__output_id_sample(struct perf_event *event,
5166 struct perf_output_handle *handle,
5167 struct perf_sample_data *sample)
5169 if (event->attr.sample_id_all)
5170 __perf_event__output_id_sample(handle, sample);
5173 static void perf_output_read_one(struct perf_output_handle *handle,
5174 struct perf_event *event,
5175 u64 enabled, u64 running)
5177 u64 read_format = event->attr.read_format;
5181 values[n++] = perf_event_count(event);
5182 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5183 values[n++] = enabled +
5184 atomic64_read(&event->child_total_time_enabled);
5186 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5187 values[n++] = running +
5188 atomic64_read(&event->child_total_time_running);
5190 if (read_format & PERF_FORMAT_ID)
5191 values[n++] = primary_event_id(event);
5193 __output_copy(handle, values, n * sizeof(u64));
5197 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5199 static void perf_output_read_group(struct perf_output_handle *handle,
5200 struct perf_event *event,
5201 u64 enabled, u64 running)
5203 struct perf_event *leader = event->group_leader, *sub;
5204 u64 read_format = event->attr.read_format;
5208 values[n++] = 1 + leader->nr_siblings;
5210 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5211 values[n++] = enabled;
5213 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5214 values[n++] = running;
5216 if (leader != event)
5217 leader->pmu->read(leader);
5219 values[n++] = perf_event_count(leader);
5220 if (read_format & PERF_FORMAT_ID)
5221 values[n++] = primary_event_id(leader);
5223 __output_copy(handle, values, n * sizeof(u64));
5225 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5228 if ((sub != event) &&
5229 (sub->state == PERF_EVENT_STATE_ACTIVE))
5230 sub->pmu->read(sub);
5232 values[n++] = perf_event_count(sub);
5233 if (read_format & PERF_FORMAT_ID)
5234 values[n++] = primary_event_id(sub);
5236 __output_copy(handle, values, n * sizeof(u64));
5240 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5241 PERF_FORMAT_TOTAL_TIME_RUNNING)
5243 static void perf_output_read(struct perf_output_handle *handle,
5244 struct perf_event *event)
5246 u64 enabled = 0, running = 0, now;
5247 u64 read_format = event->attr.read_format;
5250 * compute total_time_enabled, total_time_running
5251 * based on snapshot values taken when the event
5252 * was last scheduled in.
5254 * we cannot simply called update_context_time()
5255 * because of locking issue as we are called in
5258 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5259 calc_timer_values(event, &now, &enabled, &running);
5261 if (event->attr.read_format & PERF_FORMAT_GROUP)
5262 perf_output_read_group(handle, event, enabled, running);
5264 perf_output_read_one(handle, event, enabled, running);
5267 void perf_output_sample(struct perf_output_handle *handle,
5268 struct perf_event_header *header,
5269 struct perf_sample_data *data,
5270 struct perf_event *event)
5272 u64 sample_type = data->type;
5274 perf_output_put(handle, *header);
5276 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5277 perf_output_put(handle, data->id);
5279 if (sample_type & PERF_SAMPLE_IP)
5280 perf_output_put(handle, data->ip);
5282 if (sample_type & PERF_SAMPLE_TID)
5283 perf_output_put(handle, data->tid_entry);
5285 if (sample_type & PERF_SAMPLE_TIME)
5286 perf_output_put(handle, data->time);
5288 if (sample_type & PERF_SAMPLE_ADDR)
5289 perf_output_put(handle, data->addr);
5291 if (sample_type & PERF_SAMPLE_ID)
5292 perf_output_put(handle, data->id);
5294 if (sample_type & PERF_SAMPLE_STREAM_ID)
5295 perf_output_put(handle, data->stream_id);
5297 if (sample_type & PERF_SAMPLE_CPU)
5298 perf_output_put(handle, data->cpu_entry);
5300 if (sample_type & PERF_SAMPLE_PERIOD)
5301 perf_output_put(handle, data->period);
5303 if (sample_type & PERF_SAMPLE_READ)
5304 perf_output_read(handle, event);
5306 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5307 if (data->callchain) {
5310 if (data->callchain)
5311 size += data->callchain->nr;
5313 size *= sizeof(u64);
5315 __output_copy(handle, data->callchain, size);
5318 perf_output_put(handle, nr);
5322 if (sample_type & PERF_SAMPLE_RAW) {
5324 u32 raw_size = data->raw->size;
5325 u32 real_size = round_up(raw_size + sizeof(u32),
5326 sizeof(u64)) - sizeof(u32);
5329 perf_output_put(handle, real_size);
5330 __output_copy(handle, data->raw->data, raw_size);
5331 if (real_size - raw_size)
5332 __output_copy(handle, &zero, real_size - raw_size);
5338 .size = sizeof(u32),
5341 perf_output_put(handle, raw);
5345 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5346 if (data->br_stack) {
5349 size = data->br_stack->nr
5350 * sizeof(struct perf_branch_entry);
5352 perf_output_put(handle, data->br_stack->nr);
5353 perf_output_copy(handle, data->br_stack->entries, size);
5356 * we always store at least the value of nr
5359 perf_output_put(handle, nr);
5363 if (sample_type & PERF_SAMPLE_REGS_USER) {
5364 u64 abi = data->regs_user.abi;
5367 * If there are no regs to dump, notice it through
5368 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5370 perf_output_put(handle, abi);
5373 u64 mask = event->attr.sample_regs_user;
5374 perf_output_sample_regs(handle,
5375 data->regs_user.regs,
5380 if (sample_type & PERF_SAMPLE_STACK_USER) {
5381 perf_output_sample_ustack(handle,
5382 data->stack_user_size,
5383 data->regs_user.regs);
5386 if (sample_type & PERF_SAMPLE_WEIGHT)
5387 perf_output_put(handle, data->weight);
5389 if (sample_type & PERF_SAMPLE_DATA_SRC)
5390 perf_output_put(handle, data->data_src.val);
5392 if (sample_type & PERF_SAMPLE_TRANSACTION)
5393 perf_output_put(handle, data->txn);
5395 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5396 u64 abi = data->regs_intr.abi;
5398 * If there are no regs to dump, notice it through
5399 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5401 perf_output_put(handle, abi);
5404 u64 mask = event->attr.sample_regs_intr;
5406 perf_output_sample_regs(handle,
5407 data->regs_intr.regs,
5412 if (!event->attr.watermark) {
5413 int wakeup_events = event->attr.wakeup_events;
5415 if (wakeup_events) {
5416 struct ring_buffer *rb = handle->rb;
5417 int events = local_inc_return(&rb->events);
5419 if (events >= wakeup_events) {
5420 local_sub(wakeup_events, &rb->events);
5421 local_inc(&rb->wakeup);
5427 void perf_prepare_sample(struct perf_event_header *header,
5428 struct perf_sample_data *data,
5429 struct perf_event *event,
5430 struct pt_regs *regs)
5432 u64 sample_type = event->attr.sample_type;
5434 header->type = PERF_RECORD_SAMPLE;
5435 header->size = sizeof(*header) + event->header_size;
5438 header->misc |= perf_misc_flags(regs);
5440 __perf_event_header__init_id(header, data, event);
5442 if (sample_type & PERF_SAMPLE_IP)
5443 data->ip = perf_instruction_pointer(regs);
5445 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5448 data->callchain = perf_callchain(event, regs);
5450 if (data->callchain)
5451 size += data->callchain->nr;
5453 header->size += size * sizeof(u64);
5456 if (sample_type & PERF_SAMPLE_RAW) {
5457 int size = sizeof(u32);
5460 size += data->raw->size;
5462 size += sizeof(u32);
5464 header->size += round_up(size, sizeof(u64));
5467 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5468 int size = sizeof(u64); /* nr */
5469 if (data->br_stack) {
5470 size += data->br_stack->nr
5471 * sizeof(struct perf_branch_entry);
5473 header->size += size;
5476 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5477 perf_sample_regs_user(&data->regs_user, regs,
5478 &data->regs_user_copy);
5480 if (sample_type & PERF_SAMPLE_REGS_USER) {
5481 /* regs dump ABI info */
5482 int size = sizeof(u64);
5484 if (data->regs_user.regs) {
5485 u64 mask = event->attr.sample_regs_user;
5486 size += hweight64(mask) * sizeof(u64);
5489 header->size += size;
5492 if (sample_type & PERF_SAMPLE_STACK_USER) {
5494 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5495 * processed as the last one or have additional check added
5496 * in case new sample type is added, because we could eat
5497 * up the rest of the sample size.
5499 u16 stack_size = event->attr.sample_stack_user;
5500 u16 size = sizeof(u64);
5502 stack_size = perf_sample_ustack_size(stack_size, header->size,
5503 data->regs_user.regs);
5506 * If there is something to dump, add space for the dump
5507 * itself and for the field that tells the dynamic size,
5508 * which is how many have been actually dumped.
5511 size += sizeof(u64) + stack_size;
5513 data->stack_user_size = stack_size;
5514 header->size += size;
5517 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5518 /* regs dump ABI info */
5519 int size = sizeof(u64);
5521 perf_sample_regs_intr(&data->regs_intr, regs);
5523 if (data->regs_intr.regs) {
5524 u64 mask = event->attr.sample_regs_intr;
5526 size += hweight64(mask) * sizeof(u64);
5529 header->size += size;
5533 void perf_event_output(struct perf_event *event,
5534 struct perf_sample_data *data,
5535 struct pt_regs *regs)
5537 struct perf_output_handle handle;
5538 struct perf_event_header header;
5540 /* protect the callchain buffers */
5543 perf_prepare_sample(&header, data, event, regs);
5545 if (perf_output_begin(&handle, event, header.size))
5548 perf_output_sample(&handle, &header, data, event);
5550 perf_output_end(&handle);
5560 struct perf_read_event {
5561 struct perf_event_header header;
5568 perf_event_read_event(struct perf_event *event,
5569 struct task_struct *task)
5571 struct perf_output_handle handle;
5572 struct perf_sample_data sample;
5573 struct perf_read_event read_event = {
5575 .type = PERF_RECORD_READ,
5577 .size = sizeof(read_event) + event->read_size,
5579 .pid = perf_event_pid(event, task),
5580 .tid = perf_event_tid(event, task),
5584 perf_event_header__init_id(&read_event.header, &sample, event);
5585 ret = perf_output_begin(&handle, event, read_event.header.size);
5589 perf_output_put(&handle, read_event);
5590 perf_output_read(&handle, event);
5591 perf_event__output_id_sample(event, &handle, &sample);
5593 perf_output_end(&handle);
5596 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5599 perf_event_aux_ctx(struct perf_event_context *ctx,
5600 perf_event_aux_output_cb output,
5603 struct perf_event *event;
5605 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5606 if (event->state < PERF_EVENT_STATE_INACTIVE)
5608 if (!event_filter_match(event))
5610 output(event, data);
5615 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5616 struct perf_event_context *task_ctx)
5620 perf_event_aux_ctx(task_ctx, output, data);
5626 perf_event_aux(perf_event_aux_output_cb output, void *data,
5627 struct perf_event_context *task_ctx)
5629 struct perf_cpu_context *cpuctx;
5630 struct perf_event_context *ctx;
5635 * If we have task_ctx != NULL we only notify
5636 * the task context itself. The task_ctx is set
5637 * only for EXIT events before releasing task
5641 perf_event_aux_task_ctx(output, data, task_ctx);
5646 list_for_each_entry_rcu(pmu, &pmus, entry) {
5647 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5648 if (cpuctx->unique_pmu != pmu)
5650 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5651 ctxn = pmu->task_ctx_nr;
5654 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5656 perf_event_aux_ctx(ctx, output, data);
5658 put_cpu_ptr(pmu->pmu_cpu_context);
5664 * task tracking -- fork/exit
5666 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5669 struct perf_task_event {
5670 struct task_struct *task;
5671 struct perf_event_context *task_ctx;
5674 struct perf_event_header header;
5684 static int perf_event_task_match(struct perf_event *event)
5686 return event->attr.comm || event->attr.mmap ||
5687 event->attr.mmap2 || event->attr.mmap_data ||
5691 static void perf_event_task_output(struct perf_event *event,
5694 struct perf_task_event *task_event = data;
5695 struct perf_output_handle handle;
5696 struct perf_sample_data sample;
5697 struct task_struct *task = task_event->task;
5698 int ret, size = task_event->event_id.header.size;
5700 if (!perf_event_task_match(event))
5703 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5705 ret = perf_output_begin(&handle, event,
5706 task_event->event_id.header.size);
5710 task_event->event_id.pid = perf_event_pid(event, task);
5711 task_event->event_id.ppid = perf_event_pid(event, current);
5713 task_event->event_id.tid = perf_event_tid(event, task);
5714 task_event->event_id.ptid = perf_event_tid(event, current);
5716 task_event->event_id.time = perf_event_clock(event);
5718 perf_output_put(&handle, task_event->event_id);
5720 perf_event__output_id_sample(event, &handle, &sample);
5722 perf_output_end(&handle);
5724 task_event->event_id.header.size = size;
5727 static void perf_event_task(struct task_struct *task,
5728 struct perf_event_context *task_ctx,
5731 struct perf_task_event task_event;
5733 if (!atomic_read(&nr_comm_events) &&
5734 !atomic_read(&nr_mmap_events) &&
5735 !atomic_read(&nr_task_events))
5738 task_event = (struct perf_task_event){
5740 .task_ctx = task_ctx,
5743 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5745 .size = sizeof(task_event.event_id),
5755 perf_event_aux(perf_event_task_output,
5760 void perf_event_fork(struct task_struct *task)
5762 perf_event_task(task, NULL, 1);
5769 struct perf_comm_event {
5770 struct task_struct *task;
5775 struct perf_event_header header;
5782 static int perf_event_comm_match(struct perf_event *event)
5784 return event->attr.comm;
5787 static void perf_event_comm_output(struct perf_event *event,
5790 struct perf_comm_event *comm_event = data;
5791 struct perf_output_handle handle;
5792 struct perf_sample_data sample;
5793 int size = comm_event->event_id.header.size;
5796 if (!perf_event_comm_match(event))
5799 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5800 ret = perf_output_begin(&handle, event,
5801 comm_event->event_id.header.size);
5806 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5807 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5809 perf_output_put(&handle, comm_event->event_id);
5810 __output_copy(&handle, comm_event->comm,
5811 comm_event->comm_size);
5813 perf_event__output_id_sample(event, &handle, &sample);
5815 perf_output_end(&handle);
5817 comm_event->event_id.header.size = size;
5820 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5822 char comm[TASK_COMM_LEN];
5825 memset(comm, 0, sizeof(comm));
5826 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5827 size = ALIGN(strlen(comm)+1, sizeof(u64));
5829 comm_event->comm = comm;
5830 comm_event->comm_size = size;
5832 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5834 perf_event_aux(perf_event_comm_output,
5839 void perf_event_comm(struct task_struct *task, bool exec)
5841 struct perf_comm_event comm_event;
5843 if (!atomic_read(&nr_comm_events))
5846 comm_event = (struct perf_comm_event){
5852 .type = PERF_RECORD_COMM,
5853 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5861 perf_event_comm_event(&comm_event);
5868 struct perf_mmap_event {
5869 struct vm_area_struct *vma;
5871 const char *file_name;
5879 struct perf_event_header header;
5889 static int perf_event_mmap_match(struct perf_event *event,
5892 struct perf_mmap_event *mmap_event = data;
5893 struct vm_area_struct *vma = mmap_event->vma;
5894 int executable = vma->vm_flags & VM_EXEC;
5896 return (!executable && event->attr.mmap_data) ||
5897 (executable && (event->attr.mmap || event->attr.mmap2));
5900 static void perf_event_mmap_output(struct perf_event *event,
5903 struct perf_mmap_event *mmap_event = data;
5904 struct perf_output_handle handle;
5905 struct perf_sample_data sample;
5906 int size = mmap_event->event_id.header.size;
5909 if (!perf_event_mmap_match(event, data))
5912 if (event->attr.mmap2) {
5913 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5914 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5915 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5916 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5917 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5918 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5919 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5922 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5923 ret = perf_output_begin(&handle, event,
5924 mmap_event->event_id.header.size);
5928 mmap_event->event_id.pid = perf_event_pid(event, current);
5929 mmap_event->event_id.tid = perf_event_tid(event, current);
5931 perf_output_put(&handle, mmap_event->event_id);
5933 if (event->attr.mmap2) {
5934 perf_output_put(&handle, mmap_event->maj);
5935 perf_output_put(&handle, mmap_event->min);
5936 perf_output_put(&handle, mmap_event->ino);
5937 perf_output_put(&handle, mmap_event->ino_generation);
5938 perf_output_put(&handle, mmap_event->prot);
5939 perf_output_put(&handle, mmap_event->flags);
5942 __output_copy(&handle, mmap_event->file_name,
5943 mmap_event->file_size);
5945 perf_event__output_id_sample(event, &handle, &sample);
5947 perf_output_end(&handle);
5949 mmap_event->event_id.header.size = size;
5952 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5954 struct vm_area_struct *vma = mmap_event->vma;
5955 struct file *file = vma->vm_file;
5956 int maj = 0, min = 0;
5957 u64 ino = 0, gen = 0;
5958 u32 prot = 0, flags = 0;
5965 struct inode *inode;
5968 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5974 * d_path() works from the end of the rb backwards, so we
5975 * need to add enough zero bytes after the string to handle
5976 * the 64bit alignment we do later.
5978 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5983 inode = file_inode(vma->vm_file);
5984 dev = inode->i_sb->s_dev;
5986 gen = inode->i_generation;
5990 if (vma->vm_flags & VM_READ)
5992 if (vma->vm_flags & VM_WRITE)
5994 if (vma->vm_flags & VM_EXEC)
5997 if (vma->vm_flags & VM_MAYSHARE)
6000 flags = MAP_PRIVATE;
6002 if (vma->vm_flags & VM_DENYWRITE)
6003 flags |= MAP_DENYWRITE;
6004 if (vma->vm_flags & VM_MAYEXEC)
6005 flags |= MAP_EXECUTABLE;
6006 if (vma->vm_flags & VM_LOCKED)
6007 flags |= MAP_LOCKED;
6008 if (vma->vm_flags & VM_HUGETLB)
6009 flags |= MAP_HUGETLB;
6013 if (vma->vm_ops && vma->vm_ops->name) {
6014 name = (char *) vma->vm_ops->name(vma);
6019 name = (char *)arch_vma_name(vma);
6023 if (vma->vm_start <= vma->vm_mm->start_brk &&
6024 vma->vm_end >= vma->vm_mm->brk) {
6028 if (vma->vm_start <= vma->vm_mm->start_stack &&
6029 vma->vm_end >= vma->vm_mm->start_stack) {
6039 strlcpy(tmp, name, sizeof(tmp));
6043 * Since our buffer works in 8 byte units we need to align our string
6044 * size to a multiple of 8. However, we must guarantee the tail end is
6045 * zero'd out to avoid leaking random bits to userspace.
6047 size = strlen(name)+1;
6048 while (!IS_ALIGNED(size, sizeof(u64)))
6049 name[size++] = '\0';
6051 mmap_event->file_name = name;
6052 mmap_event->file_size = size;
6053 mmap_event->maj = maj;
6054 mmap_event->min = min;
6055 mmap_event->ino = ino;
6056 mmap_event->ino_generation = gen;
6057 mmap_event->prot = prot;
6058 mmap_event->flags = flags;
6060 if (!(vma->vm_flags & VM_EXEC))
6061 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6063 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6065 perf_event_aux(perf_event_mmap_output,
6072 void perf_event_mmap(struct vm_area_struct *vma)
6074 struct perf_mmap_event mmap_event;
6076 if (!atomic_read(&nr_mmap_events))
6079 mmap_event = (struct perf_mmap_event){
6085 .type = PERF_RECORD_MMAP,
6086 .misc = PERF_RECORD_MISC_USER,
6091 .start = vma->vm_start,
6092 .len = vma->vm_end - vma->vm_start,
6093 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6095 /* .maj (attr_mmap2 only) */
6096 /* .min (attr_mmap2 only) */
6097 /* .ino (attr_mmap2 only) */
6098 /* .ino_generation (attr_mmap2 only) */
6099 /* .prot (attr_mmap2 only) */
6100 /* .flags (attr_mmap2 only) */
6103 perf_event_mmap_event(&mmap_event);
6106 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6107 unsigned long size, u64 flags)
6109 struct perf_output_handle handle;
6110 struct perf_sample_data sample;
6111 struct perf_aux_event {
6112 struct perf_event_header header;
6118 .type = PERF_RECORD_AUX,
6120 .size = sizeof(rec),
6128 perf_event_header__init_id(&rec.header, &sample, event);
6129 ret = perf_output_begin(&handle, event, rec.header.size);
6134 perf_output_put(&handle, rec);
6135 perf_event__output_id_sample(event, &handle, &sample);
6137 perf_output_end(&handle);
6141 * Lost/dropped samples logging
6143 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6145 struct perf_output_handle handle;
6146 struct perf_sample_data sample;
6150 struct perf_event_header header;
6152 } lost_samples_event = {
6154 .type = PERF_RECORD_LOST_SAMPLES,
6156 .size = sizeof(lost_samples_event),
6161 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6163 ret = perf_output_begin(&handle, event,
6164 lost_samples_event.header.size);
6168 perf_output_put(&handle, lost_samples_event);
6169 perf_event__output_id_sample(event, &handle, &sample);
6170 perf_output_end(&handle);
6174 * context_switch tracking
6177 struct perf_switch_event {
6178 struct task_struct *task;
6179 struct task_struct *next_prev;
6182 struct perf_event_header header;
6188 static int perf_event_switch_match(struct perf_event *event)
6190 return event->attr.context_switch;
6193 static void perf_event_switch_output(struct perf_event *event, void *data)
6195 struct perf_switch_event *se = data;
6196 struct perf_output_handle handle;
6197 struct perf_sample_data sample;
6200 if (!perf_event_switch_match(event))
6203 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6204 if (event->ctx->task) {
6205 se->event_id.header.type = PERF_RECORD_SWITCH;
6206 se->event_id.header.size = sizeof(se->event_id.header);
6208 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6209 se->event_id.header.size = sizeof(se->event_id);
6210 se->event_id.next_prev_pid =
6211 perf_event_pid(event, se->next_prev);
6212 se->event_id.next_prev_tid =
6213 perf_event_tid(event, se->next_prev);
6216 perf_event_header__init_id(&se->event_id.header, &sample, event);
6218 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6222 if (event->ctx->task)
6223 perf_output_put(&handle, se->event_id.header);
6225 perf_output_put(&handle, se->event_id);
6227 perf_event__output_id_sample(event, &handle, &sample);
6229 perf_output_end(&handle);
6232 static void perf_event_switch(struct task_struct *task,
6233 struct task_struct *next_prev, bool sched_in)
6235 struct perf_switch_event switch_event;
6237 /* N.B. caller checks nr_switch_events != 0 */
6239 switch_event = (struct perf_switch_event){
6241 .next_prev = next_prev,
6245 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6248 /* .next_prev_pid */
6249 /* .next_prev_tid */
6253 perf_event_aux(perf_event_switch_output,
6259 * IRQ throttle logging
6262 static void perf_log_throttle(struct perf_event *event, int enable)
6264 struct perf_output_handle handle;
6265 struct perf_sample_data sample;
6269 struct perf_event_header header;
6273 } throttle_event = {
6275 .type = PERF_RECORD_THROTTLE,
6277 .size = sizeof(throttle_event),
6279 .time = perf_event_clock(event),
6280 .id = primary_event_id(event),
6281 .stream_id = event->id,
6285 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6287 perf_event_header__init_id(&throttle_event.header, &sample, event);
6289 ret = perf_output_begin(&handle, event,
6290 throttle_event.header.size);
6294 perf_output_put(&handle, throttle_event);
6295 perf_event__output_id_sample(event, &handle, &sample);
6296 perf_output_end(&handle);
6299 static void perf_log_itrace_start(struct perf_event *event)
6301 struct perf_output_handle handle;
6302 struct perf_sample_data sample;
6303 struct perf_aux_event {
6304 struct perf_event_header header;
6311 event = event->parent;
6313 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6314 event->hw.itrace_started)
6317 rec.header.type = PERF_RECORD_ITRACE_START;
6318 rec.header.misc = 0;
6319 rec.header.size = sizeof(rec);
6320 rec.pid = perf_event_pid(event, current);
6321 rec.tid = perf_event_tid(event, current);
6323 perf_event_header__init_id(&rec.header, &sample, event);
6324 ret = perf_output_begin(&handle, event, rec.header.size);
6329 perf_output_put(&handle, rec);
6330 perf_event__output_id_sample(event, &handle, &sample);
6332 perf_output_end(&handle);
6336 * Generic event overflow handling, sampling.
6339 static int __perf_event_overflow(struct perf_event *event,
6340 int throttle, struct perf_sample_data *data,
6341 struct pt_regs *regs)
6343 int events = atomic_read(&event->event_limit);
6344 struct hw_perf_event *hwc = &event->hw;
6349 * Non-sampling counters might still use the PMI to fold short
6350 * hardware counters, ignore those.
6352 if (unlikely(!is_sampling_event(event)))
6355 seq = __this_cpu_read(perf_throttled_seq);
6356 if (seq != hwc->interrupts_seq) {
6357 hwc->interrupts_seq = seq;
6358 hwc->interrupts = 1;
6361 if (unlikely(throttle
6362 && hwc->interrupts >= max_samples_per_tick)) {
6363 __this_cpu_inc(perf_throttled_count);
6364 hwc->interrupts = MAX_INTERRUPTS;
6365 perf_log_throttle(event, 0);
6366 tick_nohz_full_kick();
6371 if (event->attr.freq) {
6372 u64 now = perf_clock();
6373 s64 delta = now - hwc->freq_time_stamp;
6375 hwc->freq_time_stamp = now;
6377 if (delta > 0 && delta < 2*TICK_NSEC)
6378 perf_adjust_period(event, delta, hwc->last_period, true);
6382 * XXX event_limit might not quite work as expected on inherited
6386 event->pending_kill = POLL_IN;
6387 if (events && atomic_dec_and_test(&event->event_limit)) {
6389 event->pending_kill = POLL_HUP;
6390 event->pending_disable = 1;
6391 irq_work_queue(&event->pending);
6394 if (event->overflow_handler)
6395 event->overflow_handler(event, data, regs);
6397 perf_event_output(event, data, regs);
6399 if (*perf_event_fasync(event) && event->pending_kill) {
6400 event->pending_wakeup = 1;
6401 irq_work_queue(&event->pending);
6407 int perf_event_overflow(struct perf_event *event,
6408 struct perf_sample_data *data,
6409 struct pt_regs *regs)
6411 return __perf_event_overflow(event, 1, data, regs);
6415 * Generic software event infrastructure
6418 struct swevent_htable {
6419 struct swevent_hlist *swevent_hlist;
6420 struct mutex hlist_mutex;
6423 /* Recursion avoidance in each contexts */
6424 int recursion[PERF_NR_CONTEXTS];
6427 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6430 * We directly increment event->count and keep a second value in
6431 * event->hw.period_left to count intervals. This period event
6432 * is kept in the range [-sample_period, 0] so that we can use the
6436 u64 perf_swevent_set_period(struct perf_event *event)
6438 struct hw_perf_event *hwc = &event->hw;
6439 u64 period = hwc->last_period;
6443 hwc->last_period = hwc->sample_period;
6446 old = val = local64_read(&hwc->period_left);
6450 nr = div64_u64(period + val, period);
6451 offset = nr * period;
6453 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6459 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6460 struct perf_sample_data *data,
6461 struct pt_regs *regs)
6463 struct hw_perf_event *hwc = &event->hw;
6467 overflow = perf_swevent_set_period(event);
6469 if (hwc->interrupts == MAX_INTERRUPTS)
6472 for (; overflow; overflow--) {
6473 if (__perf_event_overflow(event, throttle,
6476 * We inhibit the overflow from happening when
6477 * hwc->interrupts == MAX_INTERRUPTS.
6485 static void perf_swevent_event(struct perf_event *event, u64 nr,
6486 struct perf_sample_data *data,
6487 struct pt_regs *regs)
6489 struct hw_perf_event *hwc = &event->hw;
6491 local64_add(nr, &event->count);
6496 if (!is_sampling_event(event))
6499 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6501 return perf_swevent_overflow(event, 1, data, regs);
6503 data->period = event->hw.last_period;
6505 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6506 return perf_swevent_overflow(event, 1, data, regs);
6508 if (local64_add_negative(nr, &hwc->period_left))
6511 perf_swevent_overflow(event, 0, data, regs);
6514 static int perf_exclude_event(struct perf_event *event,
6515 struct pt_regs *regs)
6517 if (event->hw.state & PERF_HES_STOPPED)
6521 if (event->attr.exclude_user && user_mode(regs))
6524 if (event->attr.exclude_kernel && !user_mode(regs))
6531 static int perf_swevent_match(struct perf_event *event,
6532 enum perf_type_id type,
6534 struct perf_sample_data *data,
6535 struct pt_regs *regs)
6537 if (event->attr.type != type)
6540 if (event->attr.config != event_id)
6543 if (perf_exclude_event(event, regs))
6549 static inline u64 swevent_hash(u64 type, u32 event_id)
6551 u64 val = event_id | (type << 32);
6553 return hash_64(val, SWEVENT_HLIST_BITS);
6556 static inline struct hlist_head *
6557 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6559 u64 hash = swevent_hash(type, event_id);
6561 return &hlist->heads[hash];
6564 /* For the read side: events when they trigger */
6565 static inline struct hlist_head *
6566 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6568 struct swevent_hlist *hlist;
6570 hlist = rcu_dereference(swhash->swevent_hlist);
6574 return __find_swevent_head(hlist, type, event_id);
6577 /* For the event head insertion and removal in the hlist */
6578 static inline struct hlist_head *
6579 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6581 struct swevent_hlist *hlist;
6582 u32 event_id = event->attr.config;
6583 u64 type = event->attr.type;
6586 * Event scheduling is always serialized against hlist allocation
6587 * and release. Which makes the protected version suitable here.
6588 * The context lock guarantees that.
6590 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6591 lockdep_is_held(&event->ctx->lock));
6595 return __find_swevent_head(hlist, type, event_id);
6598 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6600 struct perf_sample_data *data,
6601 struct pt_regs *regs)
6603 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6604 struct perf_event *event;
6605 struct hlist_head *head;
6608 head = find_swevent_head_rcu(swhash, type, event_id);
6612 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6613 if (perf_swevent_match(event, type, event_id, data, regs))
6614 perf_swevent_event(event, nr, data, regs);
6620 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6622 int perf_swevent_get_recursion_context(void)
6624 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6626 return get_recursion_context(swhash->recursion);
6628 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6630 inline void perf_swevent_put_recursion_context(int rctx)
6632 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6634 put_recursion_context(swhash->recursion, rctx);
6637 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6639 struct perf_sample_data data;
6641 if (WARN_ON_ONCE(!regs))
6644 perf_sample_data_init(&data, addr, 0);
6645 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6648 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6652 preempt_disable_notrace();
6653 rctx = perf_swevent_get_recursion_context();
6654 if (unlikely(rctx < 0))
6657 ___perf_sw_event(event_id, nr, regs, addr);
6659 perf_swevent_put_recursion_context(rctx);
6661 preempt_enable_notrace();
6664 static void perf_swevent_read(struct perf_event *event)
6668 static int perf_swevent_add(struct perf_event *event, int flags)
6670 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6671 struct hw_perf_event *hwc = &event->hw;
6672 struct hlist_head *head;
6674 if (is_sampling_event(event)) {
6675 hwc->last_period = hwc->sample_period;
6676 perf_swevent_set_period(event);
6679 hwc->state = !(flags & PERF_EF_START);
6681 head = find_swevent_head(swhash, event);
6682 if (WARN_ON_ONCE(!head))
6685 hlist_add_head_rcu(&event->hlist_entry, head);
6686 perf_event_update_userpage(event);
6691 static void perf_swevent_del(struct perf_event *event, int flags)
6693 hlist_del_rcu(&event->hlist_entry);
6696 static void perf_swevent_start(struct perf_event *event, int flags)
6698 event->hw.state = 0;
6701 static void perf_swevent_stop(struct perf_event *event, int flags)
6703 event->hw.state = PERF_HES_STOPPED;
6706 /* Deref the hlist from the update side */
6707 static inline struct swevent_hlist *
6708 swevent_hlist_deref(struct swevent_htable *swhash)
6710 return rcu_dereference_protected(swhash->swevent_hlist,
6711 lockdep_is_held(&swhash->hlist_mutex));
6714 static void swevent_hlist_release(struct swevent_htable *swhash)
6716 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6721 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6722 kfree_rcu(hlist, rcu_head);
6725 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6727 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6729 mutex_lock(&swhash->hlist_mutex);
6731 if (!--swhash->hlist_refcount)
6732 swevent_hlist_release(swhash);
6734 mutex_unlock(&swhash->hlist_mutex);
6737 static void swevent_hlist_put(struct perf_event *event)
6741 for_each_possible_cpu(cpu)
6742 swevent_hlist_put_cpu(event, cpu);
6745 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6747 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6750 mutex_lock(&swhash->hlist_mutex);
6751 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6752 struct swevent_hlist *hlist;
6754 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6759 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6761 swhash->hlist_refcount++;
6763 mutex_unlock(&swhash->hlist_mutex);
6768 static int swevent_hlist_get(struct perf_event *event)
6771 int cpu, failed_cpu;
6774 for_each_possible_cpu(cpu) {
6775 err = swevent_hlist_get_cpu(event, cpu);
6785 for_each_possible_cpu(cpu) {
6786 if (cpu == failed_cpu)
6788 swevent_hlist_put_cpu(event, cpu);
6795 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6797 static void sw_perf_event_destroy(struct perf_event *event)
6799 u64 event_id = event->attr.config;
6801 WARN_ON(event->parent);
6803 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6804 swevent_hlist_put(event);
6807 static int perf_swevent_init(struct perf_event *event)
6809 u64 event_id = event->attr.config;
6811 if (event->attr.type != PERF_TYPE_SOFTWARE)
6815 * no branch sampling for software events
6817 if (has_branch_stack(event))
6821 case PERF_COUNT_SW_CPU_CLOCK:
6822 case PERF_COUNT_SW_TASK_CLOCK:
6829 if (event_id >= PERF_COUNT_SW_MAX)
6832 if (!event->parent) {
6835 err = swevent_hlist_get(event);
6839 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6840 event->destroy = sw_perf_event_destroy;
6846 static struct pmu perf_swevent = {
6847 .task_ctx_nr = perf_sw_context,
6849 .capabilities = PERF_PMU_CAP_NO_NMI,
6851 .event_init = perf_swevent_init,
6852 .add = perf_swevent_add,
6853 .del = perf_swevent_del,
6854 .start = perf_swevent_start,
6855 .stop = perf_swevent_stop,
6856 .read = perf_swevent_read,
6859 #ifdef CONFIG_EVENT_TRACING
6861 static int perf_tp_filter_match(struct perf_event *event,
6862 struct perf_sample_data *data)
6864 void *record = data->raw->data;
6866 /* only top level events have filters set */
6868 event = event->parent;
6870 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6875 static int perf_tp_event_match(struct perf_event *event,
6876 struct perf_sample_data *data,
6877 struct pt_regs *regs)
6879 if (event->hw.state & PERF_HES_STOPPED)
6882 * All tracepoints are from kernel-space.
6884 if (event->attr.exclude_kernel)
6887 if (!perf_tp_filter_match(event, data))
6893 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6894 struct pt_regs *regs, struct hlist_head *head, int rctx,
6895 struct task_struct *task)
6897 struct perf_sample_data data;
6898 struct perf_event *event;
6900 struct perf_raw_record raw = {
6905 perf_sample_data_init(&data, addr, 0);
6908 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6909 if (perf_tp_event_match(event, &data, regs))
6910 perf_swevent_event(event, count, &data, regs);
6914 * If we got specified a target task, also iterate its context and
6915 * deliver this event there too.
6917 if (task && task != current) {
6918 struct perf_event_context *ctx;
6919 struct trace_entry *entry = record;
6922 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6926 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6927 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6929 if (event->attr.config != entry->type)
6931 if (perf_tp_event_match(event, &data, regs))
6932 perf_swevent_event(event, count, &data, regs);
6938 perf_swevent_put_recursion_context(rctx);
6940 EXPORT_SYMBOL_GPL(perf_tp_event);
6942 static void tp_perf_event_destroy(struct perf_event *event)
6944 perf_trace_destroy(event);
6947 static int perf_tp_event_init(struct perf_event *event)
6951 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6955 * no branch sampling for tracepoint events
6957 if (has_branch_stack(event))
6960 err = perf_trace_init(event);
6964 event->destroy = tp_perf_event_destroy;
6969 static struct pmu perf_tracepoint = {
6970 .task_ctx_nr = perf_sw_context,
6972 .event_init = perf_tp_event_init,
6973 .add = perf_trace_add,
6974 .del = perf_trace_del,
6975 .start = perf_swevent_start,
6976 .stop = perf_swevent_stop,
6977 .read = perf_swevent_read,
6980 static inline void perf_tp_register(void)
6982 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6985 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6990 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6993 filter_str = strndup_user(arg, PAGE_SIZE);
6994 if (IS_ERR(filter_str))
6995 return PTR_ERR(filter_str);
6997 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7003 static void perf_event_free_filter(struct perf_event *event)
7005 ftrace_profile_free_filter(event);
7008 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7010 struct bpf_prog *prog;
7012 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7015 if (event->tp_event->prog)
7018 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7019 /* bpf programs can only be attached to u/kprobes */
7022 prog = bpf_prog_get(prog_fd);
7024 return PTR_ERR(prog);
7026 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7027 /* valid fd, but invalid bpf program type */
7032 event->tp_event->prog = prog;
7037 static void perf_event_free_bpf_prog(struct perf_event *event)
7039 struct bpf_prog *prog;
7041 if (!event->tp_event)
7044 prog = event->tp_event->prog;
7046 event->tp_event->prog = NULL;
7053 static inline void perf_tp_register(void)
7057 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7062 static void perf_event_free_filter(struct perf_event *event)
7066 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7071 static void perf_event_free_bpf_prog(struct perf_event *event)
7074 #endif /* CONFIG_EVENT_TRACING */
7076 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7077 void perf_bp_event(struct perf_event *bp, void *data)
7079 struct perf_sample_data sample;
7080 struct pt_regs *regs = data;
7082 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7084 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7085 perf_swevent_event(bp, 1, &sample, regs);
7090 * hrtimer based swevent callback
7093 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7095 enum hrtimer_restart ret = HRTIMER_RESTART;
7096 struct perf_sample_data data;
7097 struct pt_regs *regs;
7098 struct perf_event *event;
7101 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7103 if (event->state != PERF_EVENT_STATE_ACTIVE)
7104 return HRTIMER_NORESTART;
7106 event->pmu->read(event);
7108 perf_sample_data_init(&data, 0, event->hw.last_period);
7109 regs = get_irq_regs();
7111 if (regs && !perf_exclude_event(event, regs)) {
7112 if (!(event->attr.exclude_idle && is_idle_task(current)))
7113 if (__perf_event_overflow(event, 1, &data, regs))
7114 ret = HRTIMER_NORESTART;
7117 period = max_t(u64, 10000, event->hw.sample_period);
7118 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7123 static void perf_swevent_start_hrtimer(struct perf_event *event)
7125 struct hw_perf_event *hwc = &event->hw;
7128 if (!is_sampling_event(event))
7131 period = local64_read(&hwc->period_left);
7136 local64_set(&hwc->period_left, 0);
7138 period = max_t(u64, 10000, hwc->sample_period);
7140 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7141 HRTIMER_MODE_REL_PINNED);
7144 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7146 struct hw_perf_event *hwc = &event->hw;
7148 if (is_sampling_event(event)) {
7149 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7150 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7152 hrtimer_cancel(&hwc->hrtimer);
7156 static void perf_swevent_init_hrtimer(struct perf_event *event)
7158 struct hw_perf_event *hwc = &event->hw;
7160 if (!is_sampling_event(event))
7163 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7164 hwc->hrtimer.function = perf_swevent_hrtimer;
7167 * Since hrtimers have a fixed rate, we can do a static freq->period
7168 * mapping and avoid the whole period adjust feedback stuff.
7170 if (event->attr.freq) {
7171 long freq = event->attr.sample_freq;
7173 event->attr.sample_period = NSEC_PER_SEC / freq;
7174 hwc->sample_period = event->attr.sample_period;
7175 local64_set(&hwc->period_left, hwc->sample_period);
7176 hwc->last_period = hwc->sample_period;
7177 event->attr.freq = 0;
7182 * Software event: cpu wall time clock
7185 static void cpu_clock_event_update(struct perf_event *event)
7190 now = local_clock();
7191 prev = local64_xchg(&event->hw.prev_count, now);
7192 local64_add(now - prev, &event->count);
7195 static void cpu_clock_event_start(struct perf_event *event, int flags)
7197 local64_set(&event->hw.prev_count, local_clock());
7198 perf_swevent_start_hrtimer(event);
7201 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7203 perf_swevent_cancel_hrtimer(event);
7204 cpu_clock_event_update(event);
7207 static int cpu_clock_event_add(struct perf_event *event, int flags)
7209 if (flags & PERF_EF_START)
7210 cpu_clock_event_start(event, flags);
7211 perf_event_update_userpage(event);
7216 static void cpu_clock_event_del(struct perf_event *event, int flags)
7218 cpu_clock_event_stop(event, flags);
7221 static void cpu_clock_event_read(struct perf_event *event)
7223 cpu_clock_event_update(event);
7226 static int cpu_clock_event_init(struct perf_event *event)
7228 if (event->attr.type != PERF_TYPE_SOFTWARE)
7231 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7235 * no branch sampling for software events
7237 if (has_branch_stack(event))
7240 perf_swevent_init_hrtimer(event);
7245 static struct pmu perf_cpu_clock = {
7246 .task_ctx_nr = perf_sw_context,
7248 .capabilities = PERF_PMU_CAP_NO_NMI,
7250 .event_init = cpu_clock_event_init,
7251 .add = cpu_clock_event_add,
7252 .del = cpu_clock_event_del,
7253 .start = cpu_clock_event_start,
7254 .stop = cpu_clock_event_stop,
7255 .read = cpu_clock_event_read,
7259 * Software event: task time clock
7262 static void task_clock_event_update(struct perf_event *event, u64 now)
7267 prev = local64_xchg(&event->hw.prev_count, now);
7269 local64_add(delta, &event->count);
7272 static void task_clock_event_start(struct perf_event *event, int flags)
7274 local64_set(&event->hw.prev_count, event->ctx->time);
7275 perf_swevent_start_hrtimer(event);
7278 static void task_clock_event_stop(struct perf_event *event, int flags)
7280 perf_swevent_cancel_hrtimer(event);
7281 task_clock_event_update(event, event->ctx->time);
7284 static int task_clock_event_add(struct perf_event *event, int flags)
7286 if (flags & PERF_EF_START)
7287 task_clock_event_start(event, flags);
7288 perf_event_update_userpage(event);
7293 static void task_clock_event_del(struct perf_event *event, int flags)
7295 task_clock_event_stop(event, PERF_EF_UPDATE);
7298 static void task_clock_event_read(struct perf_event *event)
7300 u64 now = perf_clock();
7301 u64 delta = now - event->ctx->timestamp;
7302 u64 time = event->ctx->time + delta;
7304 task_clock_event_update(event, time);
7307 static int task_clock_event_init(struct perf_event *event)
7309 if (event->attr.type != PERF_TYPE_SOFTWARE)
7312 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7316 * no branch sampling for software events
7318 if (has_branch_stack(event))
7321 perf_swevent_init_hrtimer(event);
7326 static struct pmu perf_task_clock = {
7327 .task_ctx_nr = perf_sw_context,
7329 .capabilities = PERF_PMU_CAP_NO_NMI,
7331 .event_init = task_clock_event_init,
7332 .add = task_clock_event_add,
7333 .del = task_clock_event_del,
7334 .start = task_clock_event_start,
7335 .stop = task_clock_event_stop,
7336 .read = task_clock_event_read,
7339 static void perf_pmu_nop_void(struct pmu *pmu)
7343 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7347 static int perf_pmu_nop_int(struct pmu *pmu)
7352 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7354 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7356 __this_cpu_write(nop_txn_flags, flags);
7358 if (flags & ~PERF_PMU_TXN_ADD)
7361 perf_pmu_disable(pmu);
7364 static int perf_pmu_commit_txn(struct pmu *pmu)
7366 unsigned int flags = __this_cpu_read(nop_txn_flags);
7368 __this_cpu_write(nop_txn_flags, 0);
7370 if (flags & ~PERF_PMU_TXN_ADD)
7373 perf_pmu_enable(pmu);
7377 static void perf_pmu_cancel_txn(struct pmu *pmu)
7379 unsigned int flags = __this_cpu_read(nop_txn_flags);
7381 __this_cpu_write(nop_txn_flags, 0);
7383 if (flags & ~PERF_PMU_TXN_ADD)
7386 perf_pmu_enable(pmu);
7389 static int perf_event_idx_default(struct perf_event *event)
7395 * Ensures all contexts with the same task_ctx_nr have the same
7396 * pmu_cpu_context too.
7398 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7405 list_for_each_entry(pmu, &pmus, entry) {
7406 if (pmu->task_ctx_nr == ctxn)
7407 return pmu->pmu_cpu_context;
7413 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7417 for_each_possible_cpu(cpu) {
7418 struct perf_cpu_context *cpuctx;
7420 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7422 if (cpuctx->unique_pmu == old_pmu)
7423 cpuctx->unique_pmu = pmu;
7427 static void free_pmu_context(struct pmu *pmu)
7431 mutex_lock(&pmus_lock);
7433 * Like a real lame refcount.
7435 list_for_each_entry(i, &pmus, entry) {
7436 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7437 update_pmu_context(i, pmu);
7442 free_percpu(pmu->pmu_cpu_context);
7444 mutex_unlock(&pmus_lock);
7446 static struct idr pmu_idr;
7449 type_show(struct device *dev, struct device_attribute *attr, char *page)
7451 struct pmu *pmu = dev_get_drvdata(dev);
7453 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7455 static DEVICE_ATTR_RO(type);
7458 perf_event_mux_interval_ms_show(struct device *dev,
7459 struct device_attribute *attr,
7462 struct pmu *pmu = dev_get_drvdata(dev);
7464 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7467 static DEFINE_MUTEX(mux_interval_mutex);
7470 perf_event_mux_interval_ms_store(struct device *dev,
7471 struct device_attribute *attr,
7472 const char *buf, size_t count)
7474 struct pmu *pmu = dev_get_drvdata(dev);
7475 int timer, cpu, ret;
7477 ret = kstrtoint(buf, 0, &timer);
7484 /* same value, noting to do */
7485 if (timer == pmu->hrtimer_interval_ms)
7488 mutex_lock(&mux_interval_mutex);
7489 pmu->hrtimer_interval_ms = timer;
7491 /* update all cpuctx for this PMU */
7493 for_each_online_cpu(cpu) {
7494 struct perf_cpu_context *cpuctx;
7495 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7496 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7498 cpu_function_call(cpu,
7499 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7502 mutex_unlock(&mux_interval_mutex);
7506 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7508 static struct attribute *pmu_dev_attrs[] = {
7509 &dev_attr_type.attr,
7510 &dev_attr_perf_event_mux_interval_ms.attr,
7513 ATTRIBUTE_GROUPS(pmu_dev);
7515 static int pmu_bus_running;
7516 static struct bus_type pmu_bus = {
7517 .name = "event_source",
7518 .dev_groups = pmu_dev_groups,
7521 static void pmu_dev_release(struct device *dev)
7526 static int pmu_dev_alloc(struct pmu *pmu)
7530 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7534 pmu->dev->groups = pmu->attr_groups;
7535 device_initialize(pmu->dev);
7536 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7540 dev_set_drvdata(pmu->dev, pmu);
7541 pmu->dev->bus = &pmu_bus;
7542 pmu->dev->release = pmu_dev_release;
7543 ret = device_add(pmu->dev);
7551 put_device(pmu->dev);
7555 static struct lock_class_key cpuctx_mutex;
7556 static struct lock_class_key cpuctx_lock;
7558 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7562 mutex_lock(&pmus_lock);
7564 pmu->pmu_disable_count = alloc_percpu(int);
7565 if (!pmu->pmu_disable_count)
7574 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7582 if (pmu_bus_running) {
7583 ret = pmu_dev_alloc(pmu);
7589 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7590 if (pmu->pmu_cpu_context)
7591 goto got_cpu_context;
7594 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7595 if (!pmu->pmu_cpu_context)
7598 for_each_possible_cpu(cpu) {
7599 struct perf_cpu_context *cpuctx;
7601 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7602 __perf_event_init_context(&cpuctx->ctx);
7603 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7604 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7605 cpuctx->ctx.pmu = pmu;
7607 __perf_mux_hrtimer_init(cpuctx, cpu);
7609 cpuctx->unique_pmu = pmu;
7613 if (!pmu->start_txn) {
7614 if (pmu->pmu_enable) {
7616 * If we have pmu_enable/pmu_disable calls, install
7617 * transaction stubs that use that to try and batch
7618 * hardware accesses.
7620 pmu->start_txn = perf_pmu_start_txn;
7621 pmu->commit_txn = perf_pmu_commit_txn;
7622 pmu->cancel_txn = perf_pmu_cancel_txn;
7624 pmu->start_txn = perf_pmu_nop_txn;
7625 pmu->commit_txn = perf_pmu_nop_int;
7626 pmu->cancel_txn = perf_pmu_nop_void;
7630 if (!pmu->pmu_enable) {
7631 pmu->pmu_enable = perf_pmu_nop_void;
7632 pmu->pmu_disable = perf_pmu_nop_void;
7635 if (!pmu->event_idx)
7636 pmu->event_idx = perf_event_idx_default;
7638 list_add_rcu(&pmu->entry, &pmus);
7639 atomic_set(&pmu->exclusive_cnt, 0);
7642 mutex_unlock(&pmus_lock);
7647 device_del(pmu->dev);
7648 put_device(pmu->dev);
7651 if (pmu->type >= PERF_TYPE_MAX)
7652 idr_remove(&pmu_idr, pmu->type);
7655 free_percpu(pmu->pmu_disable_count);
7658 EXPORT_SYMBOL_GPL(perf_pmu_register);
7660 void perf_pmu_unregister(struct pmu *pmu)
7662 mutex_lock(&pmus_lock);
7663 list_del_rcu(&pmu->entry);
7664 mutex_unlock(&pmus_lock);
7667 * We dereference the pmu list under both SRCU and regular RCU, so
7668 * synchronize against both of those.
7670 synchronize_srcu(&pmus_srcu);
7673 free_percpu(pmu->pmu_disable_count);
7674 if (pmu->type >= PERF_TYPE_MAX)
7675 idr_remove(&pmu_idr, pmu->type);
7676 device_del(pmu->dev);
7677 put_device(pmu->dev);
7678 free_pmu_context(pmu);
7680 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7682 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7684 struct perf_event_context *ctx = NULL;
7687 if (!try_module_get(pmu->module))
7690 if (event->group_leader != event) {
7692 * This ctx->mutex can nest when we're called through
7693 * inheritance. See the perf_event_ctx_lock_nested() comment.
7695 ctx = perf_event_ctx_lock_nested(event->group_leader,
7696 SINGLE_DEPTH_NESTING);
7701 ret = pmu->event_init(event);
7704 perf_event_ctx_unlock(event->group_leader, ctx);
7707 module_put(pmu->module);
7712 static struct pmu *perf_init_event(struct perf_event *event)
7714 struct pmu *pmu = NULL;
7718 idx = srcu_read_lock(&pmus_srcu);
7721 pmu = idr_find(&pmu_idr, event->attr.type);
7724 ret = perf_try_init_event(pmu, event);
7730 list_for_each_entry_rcu(pmu, &pmus, entry) {
7731 ret = perf_try_init_event(pmu, event);
7735 if (ret != -ENOENT) {
7740 pmu = ERR_PTR(-ENOENT);
7742 srcu_read_unlock(&pmus_srcu, idx);
7747 static void account_event_cpu(struct perf_event *event, int cpu)
7752 if (is_cgroup_event(event))
7753 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7756 static void account_event(struct perf_event *event)
7763 if (event->attach_state & PERF_ATTACH_TASK)
7765 if (event->attr.mmap || event->attr.mmap_data)
7766 atomic_inc(&nr_mmap_events);
7767 if (event->attr.comm)
7768 atomic_inc(&nr_comm_events);
7769 if (event->attr.task)
7770 atomic_inc(&nr_task_events);
7771 if (event->attr.freq) {
7772 if (atomic_inc_return(&nr_freq_events) == 1)
7773 tick_nohz_full_kick_all();
7775 if (event->attr.context_switch) {
7776 atomic_inc(&nr_switch_events);
7779 if (has_branch_stack(event))
7781 if (is_cgroup_event(event))
7785 static_key_slow_inc(&perf_sched_events.key);
7787 account_event_cpu(event, event->cpu);
7791 * Allocate and initialize a event structure
7793 static struct perf_event *
7794 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7795 struct task_struct *task,
7796 struct perf_event *group_leader,
7797 struct perf_event *parent_event,
7798 perf_overflow_handler_t overflow_handler,
7799 void *context, int cgroup_fd)
7802 struct perf_event *event;
7803 struct hw_perf_event *hwc;
7806 if ((unsigned)cpu >= nr_cpu_ids) {
7807 if (!task || cpu != -1)
7808 return ERR_PTR(-EINVAL);
7811 event = kzalloc(sizeof(*event), GFP_KERNEL);
7813 return ERR_PTR(-ENOMEM);
7816 * Single events are their own group leaders, with an
7817 * empty sibling list:
7820 group_leader = event;
7822 mutex_init(&event->child_mutex);
7823 INIT_LIST_HEAD(&event->child_list);
7825 INIT_LIST_HEAD(&event->group_entry);
7826 INIT_LIST_HEAD(&event->event_entry);
7827 INIT_LIST_HEAD(&event->sibling_list);
7828 INIT_LIST_HEAD(&event->rb_entry);
7829 INIT_LIST_HEAD(&event->active_entry);
7830 INIT_HLIST_NODE(&event->hlist_entry);
7833 init_waitqueue_head(&event->waitq);
7834 init_irq_work(&event->pending, perf_pending_event);
7836 mutex_init(&event->mmap_mutex);
7838 atomic_long_set(&event->refcount, 1);
7840 event->attr = *attr;
7841 event->group_leader = group_leader;
7845 event->parent = parent_event;
7847 event->ns = get_pid_ns(task_active_pid_ns(current));
7848 event->id = atomic64_inc_return(&perf_event_id);
7850 event->state = PERF_EVENT_STATE_INACTIVE;
7853 event->attach_state = PERF_ATTACH_TASK;
7855 * XXX pmu::event_init needs to know what task to account to
7856 * and we cannot use the ctx information because we need the
7857 * pmu before we get a ctx.
7859 event->hw.target = task;
7862 event->clock = &local_clock;
7864 event->clock = parent_event->clock;
7866 if (!overflow_handler && parent_event) {
7867 overflow_handler = parent_event->overflow_handler;
7868 context = parent_event->overflow_handler_context;
7871 event->overflow_handler = overflow_handler;
7872 event->overflow_handler_context = context;
7874 perf_event__state_init(event);
7879 hwc->sample_period = attr->sample_period;
7880 if (attr->freq && attr->sample_freq)
7881 hwc->sample_period = 1;
7882 hwc->last_period = hwc->sample_period;
7884 local64_set(&hwc->period_left, hwc->sample_period);
7887 * we currently do not support PERF_FORMAT_GROUP on inherited events
7889 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7892 if (!has_branch_stack(event))
7893 event->attr.branch_sample_type = 0;
7895 if (cgroup_fd != -1) {
7896 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7901 pmu = perf_init_event(event);
7904 else if (IS_ERR(pmu)) {
7909 err = exclusive_event_init(event);
7913 if (!event->parent) {
7914 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7915 err = get_callchain_buffers();
7924 exclusive_event_destroy(event);
7928 event->destroy(event);
7929 module_put(pmu->module);
7931 if (is_cgroup_event(event))
7932 perf_detach_cgroup(event);
7934 put_pid_ns(event->ns);
7937 return ERR_PTR(err);
7940 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7941 struct perf_event_attr *attr)
7946 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7950 * zero the full structure, so that a short copy will be nice.
7952 memset(attr, 0, sizeof(*attr));
7954 ret = get_user(size, &uattr->size);
7958 if (size > PAGE_SIZE) /* silly large */
7961 if (!size) /* abi compat */
7962 size = PERF_ATTR_SIZE_VER0;
7964 if (size < PERF_ATTR_SIZE_VER0)
7968 * If we're handed a bigger struct than we know of,
7969 * ensure all the unknown bits are 0 - i.e. new
7970 * user-space does not rely on any kernel feature
7971 * extensions we dont know about yet.
7973 if (size > sizeof(*attr)) {
7974 unsigned char __user *addr;
7975 unsigned char __user *end;
7978 addr = (void __user *)uattr + sizeof(*attr);
7979 end = (void __user *)uattr + size;
7981 for (; addr < end; addr++) {
7982 ret = get_user(val, addr);
7988 size = sizeof(*attr);
7991 ret = copy_from_user(attr, uattr, size);
7995 if (attr->__reserved_1)
7998 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8001 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8004 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8005 u64 mask = attr->branch_sample_type;
8007 /* only using defined bits */
8008 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8011 /* at least one branch bit must be set */
8012 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8015 /* propagate priv level, when not set for branch */
8016 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8018 /* exclude_kernel checked on syscall entry */
8019 if (!attr->exclude_kernel)
8020 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8022 if (!attr->exclude_user)
8023 mask |= PERF_SAMPLE_BRANCH_USER;
8025 if (!attr->exclude_hv)
8026 mask |= PERF_SAMPLE_BRANCH_HV;
8028 * adjust user setting (for HW filter setup)
8030 attr->branch_sample_type = mask;
8032 /* privileged levels capture (kernel, hv): check permissions */
8033 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8034 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8038 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8039 ret = perf_reg_validate(attr->sample_regs_user);
8044 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8045 if (!arch_perf_have_user_stack_dump())
8049 * We have __u32 type for the size, but so far
8050 * we can only use __u16 as maximum due to the
8051 * __u16 sample size limit.
8053 if (attr->sample_stack_user >= USHRT_MAX)
8055 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8059 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8060 ret = perf_reg_validate(attr->sample_regs_intr);
8065 put_user(sizeof(*attr), &uattr->size);
8071 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8073 struct ring_buffer *rb = NULL;
8079 /* don't allow circular references */
8080 if (event == output_event)
8084 * Don't allow cross-cpu buffers
8086 if (output_event->cpu != event->cpu)
8090 * If its not a per-cpu rb, it must be the same task.
8092 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8096 * Mixing clocks in the same buffer is trouble you don't need.
8098 if (output_event->clock != event->clock)
8102 * If both events generate aux data, they must be on the same PMU
8104 if (has_aux(event) && has_aux(output_event) &&
8105 event->pmu != output_event->pmu)
8109 mutex_lock(&event->mmap_mutex);
8110 /* Can't redirect output if we've got an active mmap() */
8111 if (atomic_read(&event->mmap_count))
8115 /* get the rb we want to redirect to */
8116 rb = ring_buffer_get(output_event);
8121 ring_buffer_attach(event, rb);
8125 mutex_unlock(&event->mmap_mutex);
8131 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8137 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8140 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8142 bool nmi_safe = false;
8145 case CLOCK_MONOTONIC:
8146 event->clock = &ktime_get_mono_fast_ns;
8150 case CLOCK_MONOTONIC_RAW:
8151 event->clock = &ktime_get_raw_fast_ns;
8155 case CLOCK_REALTIME:
8156 event->clock = &ktime_get_real_ns;
8159 case CLOCK_BOOTTIME:
8160 event->clock = &ktime_get_boot_ns;
8164 event->clock = &ktime_get_tai_ns;
8171 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8178 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8180 * @attr_uptr: event_id type attributes for monitoring/sampling
8183 * @group_fd: group leader event fd
8185 SYSCALL_DEFINE5(perf_event_open,
8186 struct perf_event_attr __user *, attr_uptr,
8187 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8189 struct perf_event *group_leader = NULL, *output_event = NULL;
8190 struct perf_event *event, *sibling;
8191 struct perf_event_attr attr;
8192 struct perf_event_context *ctx, *uninitialized_var(gctx);
8193 struct file *event_file = NULL;
8194 struct fd group = {NULL, 0};
8195 struct task_struct *task = NULL;
8200 int f_flags = O_RDWR;
8203 /* for future expandability... */
8204 if (flags & ~PERF_FLAG_ALL)
8207 err = perf_copy_attr(attr_uptr, &attr);
8211 if (!attr.exclude_kernel) {
8212 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8217 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8220 if (attr.sample_period & (1ULL << 63))
8225 * In cgroup mode, the pid argument is used to pass the fd
8226 * opened to the cgroup directory in cgroupfs. The cpu argument
8227 * designates the cpu on which to monitor threads from that
8230 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8233 if (flags & PERF_FLAG_FD_CLOEXEC)
8234 f_flags |= O_CLOEXEC;
8236 event_fd = get_unused_fd_flags(f_flags);
8240 if (group_fd != -1) {
8241 err = perf_fget_light(group_fd, &group);
8244 group_leader = group.file->private_data;
8245 if (flags & PERF_FLAG_FD_OUTPUT)
8246 output_event = group_leader;
8247 if (flags & PERF_FLAG_FD_NO_GROUP)
8248 group_leader = NULL;
8251 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8252 task = find_lively_task_by_vpid(pid);
8254 err = PTR_ERR(task);
8259 if (task && group_leader &&
8260 group_leader->attr.inherit != attr.inherit) {
8267 if (flags & PERF_FLAG_PID_CGROUP)
8270 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8271 NULL, NULL, cgroup_fd);
8272 if (IS_ERR(event)) {
8273 err = PTR_ERR(event);
8277 if (is_sampling_event(event)) {
8278 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8284 account_event(event);
8287 * Special case software events and allow them to be part of
8288 * any hardware group.
8292 if (attr.use_clockid) {
8293 err = perf_event_set_clock(event, attr.clockid);
8299 (is_software_event(event) != is_software_event(group_leader))) {
8300 if (is_software_event(event)) {
8302 * If event and group_leader are not both a software
8303 * event, and event is, then group leader is not.
8305 * Allow the addition of software events to !software
8306 * groups, this is safe because software events never
8309 pmu = group_leader->pmu;
8310 } else if (is_software_event(group_leader) &&
8311 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8313 * In case the group is a pure software group, and we
8314 * try to add a hardware event, move the whole group to
8315 * the hardware context.
8322 * Get the target context (task or percpu):
8324 ctx = find_get_context(pmu, task, event);
8330 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8336 put_task_struct(task);
8341 * Look up the group leader (we will attach this event to it):
8347 * Do not allow a recursive hierarchy (this new sibling
8348 * becoming part of another group-sibling):
8350 if (group_leader->group_leader != group_leader)
8353 /* All events in a group should have the same clock */
8354 if (group_leader->clock != event->clock)
8358 * Do not allow to attach to a group in a different
8359 * task or CPU context:
8363 * Make sure we're both on the same task, or both
8366 if (group_leader->ctx->task != ctx->task)
8370 * Make sure we're both events for the same CPU;
8371 * grouping events for different CPUs is broken; since
8372 * you can never concurrently schedule them anyhow.
8374 if (group_leader->cpu != event->cpu)
8377 if (group_leader->ctx != ctx)
8382 * Only a group leader can be exclusive or pinned
8384 if (attr.exclusive || attr.pinned)
8389 err = perf_event_set_output(event, output_event);
8394 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8396 if (IS_ERR(event_file)) {
8397 err = PTR_ERR(event_file);
8402 gctx = group_leader->ctx;
8403 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8405 mutex_lock(&ctx->mutex);
8408 if (!perf_event_validate_size(event)) {
8414 * Must be under the same ctx::mutex as perf_install_in_context(),
8415 * because we need to serialize with concurrent event creation.
8417 if (!exclusive_event_installable(event, ctx)) {
8418 /* exclusive and group stuff are assumed mutually exclusive */
8419 WARN_ON_ONCE(move_group);
8425 WARN_ON_ONCE(ctx->parent_ctx);
8429 * See perf_event_ctx_lock() for comments on the details
8430 * of swizzling perf_event::ctx.
8432 perf_remove_from_context(group_leader, false);
8434 list_for_each_entry(sibling, &group_leader->sibling_list,
8436 perf_remove_from_context(sibling, false);
8441 * Wait for everybody to stop referencing the events through
8442 * the old lists, before installing it on new lists.
8447 * Install the group siblings before the group leader.
8449 * Because a group leader will try and install the entire group
8450 * (through the sibling list, which is still in-tact), we can
8451 * end up with siblings installed in the wrong context.
8453 * By installing siblings first we NO-OP because they're not
8454 * reachable through the group lists.
8456 list_for_each_entry(sibling, &group_leader->sibling_list,
8458 perf_event__state_init(sibling);
8459 perf_install_in_context(ctx, sibling, sibling->cpu);
8464 * Removing from the context ends up with disabled
8465 * event. What we want here is event in the initial
8466 * startup state, ready to be add into new context.
8468 perf_event__state_init(group_leader);
8469 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8473 * Now that all events are installed in @ctx, nothing
8474 * references @gctx anymore, so drop the last reference we have
8481 * Precalculate sample_data sizes; do while holding ctx::mutex such
8482 * that we're serialized against further additions and before
8483 * perf_install_in_context() which is the point the event is active and
8484 * can use these values.
8486 perf_event__header_size(event);
8487 perf_event__id_header_size(event);
8489 event->owner = current;
8491 perf_install_in_context(ctx, event, event->cpu);
8492 perf_unpin_context(ctx);
8495 mutex_unlock(&gctx->mutex);
8496 mutex_unlock(&ctx->mutex);
8500 mutex_lock(¤t->perf_event_mutex);
8501 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8502 mutex_unlock(¤t->perf_event_mutex);
8505 * Drop the reference on the group_event after placing the
8506 * new event on the sibling_list. This ensures destruction
8507 * of the group leader will find the pointer to itself in
8508 * perf_group_detach().
8511 fd_install(event_fd, event_file);
8516 mutex_unlock(&gctx->mutex);
8517 mutex_unlock(&ctx->mutex);
8521 perf_unpin_context(ctx);
8529 put_task_struct(task);
8533 put_unused_fd(event_fd);
8538 * perf_event_create_kernel_counter
8540 * @attr: attributes of the counter to create
8541 * @cpu: cpu in which the counter is bound
8542 * @task: task to profile (NULL for percpu)
8545 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8546 struct task_struct *task,
8547 perf_overflow_handler_t overflow_handler,
8550 struct perf_event_context *ctx;
8551 struct perf_event *event;
8555 * Get the target context (task or percpu):
8558 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8559 overflow_handler, context, -1);
8560 if (IS_ERR(event)) {
8561 err = PTR_ERR(event);
8565 /* Mark owner so we could distinguish it from user events. */
8566 event->owner = TASK_TOMBSTONE;
8568 account_event(event);
8570 ctx = find_get_context(event->pmu, task, event);
8576 WARN_ON_ONCE(ctx->parent_ctx);
8577 mutex_lock(&ctx->mutex);
8578 if (!exclusive_event_installable(event, ctx)) {
8579 mutex_unlock(&ctx->mutex);
8580 perf_unpin_context(ctx);
8586 perf_install_in_context(ctx, event, cpu);
8587 perf_unpin_context(ctx);
8588 mutex_unlock(&ctx->mutex);
8595 return ERR_PTR(err);
8597 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8599 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8601 struct perf_event_context *src_ctx;
8602 struct perf_event_context *dst_ctx;
8603 struct perf_event *event, *tmp;
8606 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8607 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8610 * See perf_event_ctx_lock() for comments on the details
8611 * of swizzling perf_event::ctx.
8613 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8614 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8616 perf_remove_from_context(event, false);
8617 unaccount_event_cpu(event, src_cpu);
8619 list_add(&event->migrate_entry, &events);
8623 * Wait for the events to quiesce before re-instating them.
8628 * Re-instate events in 2 passes.
8630 * Skip over group leaders and only install siblings on this first
8631 * pass, siblings will not get enabled without a leader, however a
8632 * leader will enable its siblings, even if those are still on the old
8635 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8636 if (event->group_leader == event)
8639 list_del(&event->migrate_entry);
8640 if (event->state >= PERF_EVENT_STATE_OFF)
8641 event->state = PERF_EVENT_STATE_INACTIVE;
8642 account_event_cpu(event, dst_cpu);
8643 perf_install_in_context(dst_ctx, event, dst_cpu);
8648 * Once all the siblings are setup properly, install the group leaders
8651 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8652 list_del(&event->migrate_entry);
8653 if (event->state >= PERF_EVENT_STATE_OFF)
8654 event->state = PERF_EVENT_STATE_INACTIVE;
8655 account_event_cpu(event, dst_cpu);
8656 perf_install_in_context(dst_ctx, event, dst_cpu);
8659 mutex_unlock(&dst_ctx->mutex);
8660 mutex_unlock(&src_ctx->mutex);
8662 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8664 static void sync_child_event(struct perf_event *child_event,
8665 struct task_struct *child)
8667 struct perf_event *parent_event = child_event->parent;
8670 if (child_event->attr.inherit_stat)
8671 perf_event_read_event(child_event, child);
8673 child_val = perf_event_count(child_event);
8676 * Add back the child's count to the parent's count:
8678 atomic64_add(child_val, &parent_event->child_count);
8679 atomic64_add(child_event->total_time_enabled,
8680 &parent_event->child_total_time_enabled);
8681 atomic64_add(child_event->total_time_running,
8682 &parent_event->child_total_time_running);
8685 * Remove this event from the parent's list
8687 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8688 mutex_lock(&parent_event->child_mutex);
8689 list_del_init(&child_event->child_list);
8690 mutex_unlock(&parent_event->child_mutex);
8693 * Make sure user/parent get notified, that we just
8696 perf_event_wakeup(parent_event);
8699 * Release the parent event, if this was the last
8702 put_event(parent_event);
8706 __perf_event_exit_task(struct perf_event *child_event,
8707 struct perf_event_context *child_ctx,
8708 struct task_struct *child)
8711 * Do not destroy the 'original' grouping; because of the context
8712 * switch optimization the original events could've ended up in a
8713 * random child task.
8715 * If we were to destroy the original group, all group related
8716 * operations would cease to function properly after this random
8719 * Do destroy all inherited groups, we don't care about those
8720 * and being thorough is better.
8722 raw_spin_lock_irq(&child_ctx->lock);
8723 WARN_ON_ONCE(child_ctx->is_active);
8725 if (!!child_event->parent)
8726 perf_group_detach(child_event);
8727 list_del_event(child_event, child_ctx);
8728 raw_spin_unlock_irq(&child_ctx->lock);
8731 * It can happen that the parent exits first, and has events
8732 * that are still around due to the child reference. These
8733 * events need to be zapped.
8735 if (child_event->parent) {
8736 sync_child_event(child_event, child);
8737 free_event(child_event);
8739 child_event->state = PERF_EVENT_STATE_EXIT;
8740 perf_event_wakeup(child_event);
8744 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8746 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8747 struct perf_event *child_event, *next;
8749 WARN_ON_ONCE(child != current);
8751 child_ctx = perf_pin_task_context(child, ctxn);
8756 * In order to reduce the amount of tricky in ctx tear-down, we hold
8757 * ctx::mutex over the entire thing. This serializes against almost
8758 * everything that wants to access the ctx.
8760 * The exception is sys_perf_event_open() /
8761 * perf_event_create_kernel_count() which does find_get_context()
8762 * without ctx::mutex (it cannot because of the move_group double mutex
8763 * lock thing). See the comments in perf_install_in_context().
8765 * We can recurse on the same lock type through:
8767 * __perf_event_exit_task()
8768 * sync_child_event()
8770 * mutex_lock(&ctx->mutex)
8772 * But since its the parent context it won't be the same instance.
8774 mutex_lock(&child_ctx->mutex);
8777 * In a single ctx::lock section, de-schedule the events and detach the
8778 * context from the task such that we cannot ever get it scheduled back
8781 raw_spin_lock_irq(&child_ctx->lock);
8782 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8785 * Now that the context is inactive, destroy the task <-> ctx relation
8786 * and mark the context dead.
8788 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8789 put_ctx(child_ctx); /* cannot be last */
8790 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8791 put_task_struct(current); /* cannot be last */
8793 clone_ctx = unclone_ctx(child_ctx);
8794 raw_spin_unlock_irq(&child_ctx->lock);
8800 * Report the task dead after unscheduling the events so that we
8801 * won't get any samples after PERF_RECORD_EXIT. We can however still
8802 * get a few PERF_RECORD_READ events.
8804 perf_event_task(child, child_ctx, 0);
8806 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8807 __perf_event_exit_task(child_event, child_ctx, child);
8809 mutex_unlock(&child_ctx->mutex);
8815 * When a child task exits, feed back event values to parent events.
8817 void perf_event_exit_task(struct task_struct *child)
8819 struct perf_event *event, *tmp;
8822 mutex_lock(&child->perf_event_mutex);
8823 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8825 list_del_init(&event->owner_entry);
8828 * Ensure the list deletion is visible before we clear
8829 * the owner, closes a race against perf_release() where
8830 * we need to serialize on the owner->perf_event_mutex.
8833 event->owner = NULL;
8835 mutex_unlock(&child->perf_event_mutex);
8837 for_each_task_context_nr(ctxn)
8838 perf_event_exit_task_context(child, ctxn);
8841 * The perf_event_exit_task_context calls perf_event_task
8842 * with child's task_ctx, which generates EXIT events for
8843 * child contexts and sets child->perf_event_ctxp[] to NULL.
8844 * At this point we need to send EXIT events to cpu contexts.
8846 perf_event_task(child, NULL, 0);
8849 static void perf_free_event(struct perf_event *event,
8850 struct perf_event_context *ctx)
8852 struct perf_event *parent = event->parent;
8854 if (WARN_ON_ONCE(!parent))
8857 mutex_lock(&parent->child_mutex);
8858 list_del_init(&event->child_list);
8859 mutex_unlock(&parent->child_mutex);
8863 raw_spin_lock_irq(&ctx->lock);
8864 perf_group_detach(event);
8865 list_del_event(event, ctx);
8866 raw_spin_unlock_irq(&ctx->lock);
8871 * Free an unexposed, unused context as created by inheritance by
8872 * perf_event_init_task below, used by fork() in case of fail.
8874 * Not all locks are strictly required, but take them anyway to be nice and
8875 * help out with the lockdep assertions.
8877 void perf_event_free_task(struct task_struct *task)
8879 struct perf_event_context *ctx;
8880 struct perf_event *event, *tmp;
8883 for_each_task_context_nr(ctxn) {
8884 ctx = task->perf_event_ctxp[ctxn];
8888 mutex_lock(&ctx->mutex);
8890 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8892 perf_free_event(event, ctx);
8894 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8896 perf_free_event(event, ctx);
8898 if (!list_empty(&ctx->pinned_groups) ||
8899 !list_empty(&ctx->flexible_groups))
8902 mutex_unlock(&ctx->mutex);
8908 void perf_event_delayed_put(struct task_struct *task)
8912 for_each_task_context_nr(ctxn)
8913 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8916 struct file *perf_event_get(unsigned int fd)
8920 file = fget_raw(fd);
8922 return ERR_PTR(-EBADF);
8924 if (file->f_op != &perf_fops) {
8926 return ERR_PTR(-EBADF);
8932 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8935 return ERR_PTR(-EINVAL);
8937 return &event->attr;
8941 * inherit a event from parent task to child task:
8943 static struct perf_event *
8944 inherit_event(struct perf_event *parent_event,
8945 struct task_struct *parent,
8946 struct perf_event_context *parent_ctx,
8947 struct task_struct *child,
8948 struct perf_event *group_leader,
8949 struct perf_event_context *child_ctx)
8951 enum perf_event_active_state parent_state = parent_event->state;
8952 struct perf_event *child_event;
8953 unsigned long flags;
8956 * Instead of creating recursive hierarchies of events,
8957 * we link inherited events back to the original parent,
8958 * which has a filp for sure, which we use as the reference
8961 if (parent_event->parent)
8962 parent_event = parent_event->parent;
8964 child_event = perf_event_alloc(&parent_event->attr,
8967 group_leader, parent_event,
8969 if (IS_ERR(child_event))
8972 if (is_orphaned_event(parent_event) ||
8973 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8974 free_event(child_event);
8981 * Make the child state follow the state of the parent event,
8982 * not its attr.disabled bit. We hold the parent's mutex,
8983 * so we won't race with perf_event_{en, dis}able_family.
8985 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
8986 child_event->state = PERF_EVENT_STATE_INACTIVE;
8988 child_event->state = PERF_EVENT_STATE_OFF;
8990 if (parent_event->attr.freq) {
8991 u64 sample_period = parent_event->hw.sample_period;
8992 struct hw_perf_event *hwc = &child_event->hw;
8994 hwc->sample_period = sample_period;
8995 hwc->last_period = sample_period;
8997 local64_set(&hwc->period_left, sample_period);
9000 child_event->ctx = child_ctx;
9001 child_event->overflow_handler = parent_event->overflow_handler;
9002 child_event->overflow_handler_context
9003 = parent_event->overflow_handler_context;
9006 * Precalculate sample_data sizes
9008 perf_event__header_size(child_event);
9009 perf_event__id_header_size(child_event);
9012 * Link it up in the child's context:
9014 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9015 add_event_to_ctx(child_event, child_ctx);
9016 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9019 * Link this into the parent event's child list
9021 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9022 mutex_lock(&parent_event->child_mutex);
9023 list_add_tail(&child_event->child_list, &parent_event->child_list);
9024 mutex_unlock(&parent_event->child_mutex);
9029 static int inherit_group(struct perf_event *parent_event,
9030 struct task_struct *parent,
9031 struct perf_event_context *parent_ctx,
9032 struct task_struct *child,
9033 struct perf_event_context *child_ctx)
9035 struct perf_event *leader;
9036 struct perf_event *sub;
9037 struct perf_event *child_ctr;
9039 leader = inherit_event(parent_event, parent, parent_ctx,
9040 child, NULL, child_ctx);
9042 return PTR_ERR(leader);
9043 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9044 child_ctr = inherit_event(sub, parent, parent_ctx,
9045 child, leader, child_ctx);
9046 if (IS_ERR(child_ctr))
9047 return PTR_ERR(child_ctr);
9053 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9054 struct perf_event_context *parent_ctx,
9055 struct task_struct *child, int ctxn,
9059 struct perf_event_context *child_ctx;
9061 if (!event->attr.inherit) {
9066 child_ctx = child->perf_event_ctxp[ctxn];
9069 * This is executed from the parent task context, so
9070 * inherit events that have been marked for cloning.
9071 * First allocate and initialize a context for the
9075 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9079 child->perf_event_ctxp[ctxn] = child_ctx;
9082 ret = inherit_group(event, parent, parent_ctx,
9092 * Initialize the perf_event context in task_struct
9094 static int perf_event_init_context(struct task_struct *child, int ctxn)
9096 struct perf_event_context *child_ctx, *parent_ctx;
9097 struct perf_event_context *cloned_ctx;
9098 struct perf_event *event;
9099 struct task_struct *parent = current;
9100 int inherited_all = 1;
9101 unsigned long flags;
9104 if (likely(!parent->perf_event_ctxp[ctxn]))
9108 * If the parent's context is a clone, pin it so it won't get
9111 parent_ctx = perf_pin_task_context(parent, ctxn);
9116 * No need to check if parent_ctx != NULL here; since we saw
9117 * it non-NULL earlier, the only reason for it to become NULL
9118 * is if we exit, and since we're currently in the middle of
9119 * a fork we can't be exiting at the same time.
9123 * Lock the parent list. No need to lock the child - not PID
9124 * hashed yet and not running, so nobody can access it.
9126 mutex_lock(&parent_ctx->mutex);
9129 * We dont have to disable NMIs - we are only looking at
9130 * the list, not manipulating it:
9132 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9133 ret = inherit_task_group(event, parent, parent_ctx,
9134 child, ctxn, &inherited_all);
9140 * We can't hold ctx->lock when iterating the ->flexible_group list due
9141 * to allocations, but we need to prevent rotation because
9142 * rotate_ctx() will change the list from interrupt context.
9144 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9145 parent_ctx->rotate_disable = 1;
9146 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9148 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9149 ret = inherit_task_group(event, parent, parent_ctx,
9150 child, ctxn, &inherited_all);
9155 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9156 parent_ctx->rotate_disable = 0;
9158 child_ctx = child->perf_event_ctxp[ctxn];
9160 if (child_ctx && inherited_all) {
9162 * Mark the child context as a clone of the parent
9163 * context, or of whatever the parent is a clone of.
9165 * Note that if the parent is a clone, the holding of
9166 * parent_ctx->lock avoids it from being uncloned.
9168 cloned_ctx = parent_ctx->parent_ctx;
9170 child_ctx->parent_ctx = cloned_ctx;
9171 child_ctx->parent_gen = parent_ctx->parent_gen;
9173 child_ctx->parent_ctx = parent_ctx;
9174 child_ctx->parent_gen = parent_ctx->generation;
9176 get_ctx(child_ctx->parent_ctx);
9179 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9180 mutex_unlock(&parent_ctx->mutex);
9182 perf_unpin_context(parent_ctx);
9183 put_ctx(parent_ctx);
9189 * Initialize the perf_event context in task_struct
9191 int perf_event_init_task(struct task_struct *child)
9195 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9196 mutex_init(&child->perf_event_mutex);
9197 INIT_LIST_HEAD(&child->perf_event_list);
9199 for_each_task_context_nr(ctxn) {
9200 ret = perf_event_init_context(child, ctxn);
9202 perf_event_free_task(child);
9210 static void __init perf_event_init_all_cpus(void)
9212 struct swevent_htable *swhash;
9215 for_each_possible_cpu(cpu) {
9216 swhash = &per_cpu(swevent_htable, cpu);
9217 mutex_init(&swhash->hlist_mutex);
9218 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9222 static void perf_event_init_cpu(int cpu)
9224 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9226 mutex_lock(&swhash->hlist_mutex);
9227 if (swhash->hlist_refcount > 0) {
9228 struct swevent_hlist *hlist;
9230 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9232 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9234 mutex_unlock(&swhash->hlist_mutex);
9237 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9238 static void __perf_event_exit_context(void *__info)
9240 struct perf_event_context *ctx = __info;
9241 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9242 struct perf_event *event;
9244 raw_spin_lock(&ctx->lock);
9245 list_for_each_entry(event, &ctx->event_list, event_entry)
9246 __perf_remove_from_context(event, cpuctx, ctx, (void *)(unsigned long)true);
9247 raw_spin_unlock(&ctx->lock);
9250 static void perf_event_exit_cpu_context(int cpu)
9252 struct perf_event_context *ctx;
9256 idx = srcu_read_lock(&pmus_srcu);
9257 list_for_each_entry_rcu(pmu, &pmus, entry) {
9258 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9260 mutex_lock(&ctx->mutex);
9261 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9262 mutex_unlock(&ctx->mutex);
9264 srcu_read_unlock(&pmus_srcu, idx);
9267 static void perf_event_exit_cpu(int cpu)
9269 perf_event_exit_cpu_context(cpu);
9272 static inline void perf_event_exit_cpu(int cpu) { }
9276 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9280 for_each_online_cpu(cpu)
9281 perf_event_exit_cpu(cpu);
9287 * Run the perf reboot notifier at the very last possible moment so that
9288 * the generic watchdog code runs as long as possible.
9290 static struct notifier_block perf_reboot_notifier = {
9291 .notifier_call = perf_reboot,
9292 .priority = INT_MIN,
9296 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9298 unsigned int cpu = (long)hcpu;
9300 switch (action & ~CPU_TASKS_FROZEN) {
9302 case CPU_UP_PREPARE:
9303 case CPU_DOWN_FAILED:
9304 perf_event_init_cpu(cpu);
9307 case CPU_UP_CANCELED:
9308 case CPU_DOWN_PREPARE:
9309 perf_event_exit_cpu(cpu);
9318 void __init perf_event_init(void)
9324 perf_event_init_all_cpus();
9325 init_srcu_struct(&pmus_srcu);
9326 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9327 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9328 perf_pmu_register(&perf_task_clock, NULL, -1);
9330 perf_cpu_notifier(perf_cpu_notify);
9331 register_reboot_notifier(&perf_reboot_notifier);
9333 ret = init_hw_breakpoint();
9334 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9336 /* do not patch jump label more than once per second */
9337 jump_label_rate_limit(&perf_sched_events, HZ);
9340 * Build time assertion that we keep the data_head at the intended
9341 * location. IOW, validation we got the __reserved[] size right.
9343 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9347 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9350 struct perf_pmu_events_attr *pmu_attr =
9351 container_of(attr, struct perf_pmu_events_attr, attr);
9353 if (pmu_attr->event_str)
9354 return sprintf(page, "%s\n", pmu_attr->event_str);
9359 static int __init perf_event_sysfs_init(void)
9364 mutex_lock(&pmus_lock);
9366 ret = bus_register(&pmu_bus);
9370 list_for_each_entry(pmu, &pmus, entry) {
9371 if (!pmu->name || pmu->type < 0)
9374 ret = pmu_dev_alloc(pmu);
9375 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9377 pmu_bus_running = 1;
9381 mutex_unlock(&pmus_lock);
9385 device_initcall(perf_event_sysfs_init);
9387 #ifdef CONFIG_CGROUP_PERF
9388 static struct cgroup_subsys_state *
9389 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9391 struct perf_cgroup *jc;
9393 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9395 return ERR_PTR(-ENOMEM);
9397 jc->info = alloc_percpu(struct perf_cgroup_info);
9400 return ERR_PTR(-ENOMEM);
9406 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9408 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9410 free_percpu(jc->info);
9414 static int __perf_cgroup_move(void *info)
9416 struct task_struct *task = info;
9418 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9423 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9425 struct task_struct *task;
9426 struct cgroup_subsys_state *css;
9428 cgroup_taskset_for_each(task, css, tset)
9429 task_function_call(task, __perf_cgroup_move, task);
9432 struct cgroup_subsys perf_event_cgrp_subsys = {
9433 .css_alloc = perf_cgroup_css_alloc,
9434 .css_free = perf_cgroup_css_free,
9435 .attach = perf_cgroup_attach,
9437 #endif /* CONFIG_CGROUP_PERF */