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)
2259 update_context_time(ctx);
2260 __perf_event_mark_enabled(event);
2262 if (!ctx->is_active)
2265 if (!event_filter_match(event)) {
2266 if (is_cgroup_event(event)) {
2267 perf_cgroup_set_timestamp(current, ctx); // XXX ?
2268 perf_cgroup_defer_enabled(event);
2274 * If the event is in a group and isn't the group leader,
2275 * then don't put it on unless the group is on.
2277 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2280 task_ctx = cpuctx->task_ctx;
2282 WARN_ON_ONCE(task_ctx != ctx);
2284 ctx_resched(cpuctx, task_ctx);
2290 * If event->ctx is a cloned context, callers must make sure that
2291 * every task struct that event->ctx->task could possibly point to
2292 * remains valid. This condition is satisfied when called through
2293 * perf_event_for_each_child or perf_event_for_each as described
2294 * for perf_event_disable.
2296 static void _perf_event_enable(struct perf_event *event)
2298 struct perf_event_context *ctx = event->ctx;
2300 raw_spin_lock_irq(&ctx->lock);
2301 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
2302 raw_spin_unlock_irq(&ctx->lock);
2307 * If the event is in error state, clear that first.
2309 * That way, if we see the event in error state below, we know that it
2310 * has gone back into error state, as distinct from the task having
2311 * been scheduled away before the cross-call arrived.
2313 if (event->state == PERF_EVENT_STATE_ERROR)
2314 event->state = PERF_EVENT_STATE_OFF;
2315 raw_spin_unlock_irq(&ctx->lock);
2317 event_function_call(event, __perf_event_enable, NULL);
2321 * See perf_event_disable();
2323 void perf_event_enable(struct perf_event *event)
2325 struct perf_event_context *ctx;
2327 ctx = perf_event_ctx_lock(event);
2328 _perf_event_enable(event);
2329 perf_event_ctx_unlock(event, ctx);
2331 EXPORT_SYMBOL_GPL(perf_event_enable);
2333 static int _perf_event_refresh(struct perf_event *event, int refresh)
2336 * not supported on inherited events
2338 if (event->attr.inherit || !is_sampling_event(event))
2341 atomic_add(refresh, &event->event_limit);
2342 _perf_event_enable(event);
2348 * See perf_event_disable()
2350 int perf_event_refresh(struct perf_event *event, int refresh)
2352 struct perf_event_context *ctx;
2355 ctx = perf_event_ctx_lock(event);
2356 ret = _perf_event_refresh(event, refresh);
2357 perf_event_ctx_unlock(event, ctx);
2361 EXPORT_SYMBOL_GPL(perf_event_refresh);
2363 static void ctx_sched_out(struct perf_event_context *ctx,
2364 struct perf_cpu_context *cpuctx,
2365 enum event_type_t event_type)
2367 int is_active = ctx->is_active;
2368 struct perf_event *event;
2370 lockdep_assert_held(&ctx->lock);
2372 if (likely(!ctx->nr_events)) {
2374 * See __perf_remove_from_context().
2376 WARN_ON_ONCE(ctx->is_active);
2378 WARN_ON_ONCE(cpuctx->task_ctx);
2382 ctx->is_active &= ~event_type;
2384 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2385 if (!ctx->is_active)
2386 cpuctx->task_ctx = NULL;
2389 update_context_time(ctx);
2390 update_cgrp_time_from_cpuctx(cpuctx);
2391 if (!ctx->nr_active)
2394 perf_pmu_disable(ctx->pmu);
2395 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2396 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2397 group_sched_out(event, cpuctx, ctx);
2400 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2401 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2402 group_sched_out(event, cpuctx, ctx);
2404 perf_pmu_enable(ctx->pmu);
2408 * Test whether two contexts are equivalent, i.e. whether they have both been
2409 * cloned from the same version of the same context.
2411 * Equivalence is measured using a generation number in the context that is
2412 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2413 * and list_del_event().
2415 static int context_equiv(struct perf_event_context *ctx1,
2416 struct perf_event_context *ctx2)
2418 lockdep_assert_held(&ctx1->lock);
2419 lockdep_assert_held(&ctx2->lock);
2421 /* Pinning disables the swap optimization */
2422 if (ctx1->pin_count || ctx2->pin_count)
2425 /* If ctx1 is the parent of ctx2 */
2426 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2429 /* If ctx2 is the parent of ctx1 */
2430 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2434 * If ctx1 and ctx2 have the same parent; we flatten the parent
2435 * hierarchy, see perf_event_init_context().
2437 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2438 ctx1->parent_gen == ctx2->parent_gen)
2445 static void __perf_event_sync_stat(struct perf_event *event,
2446 struct perf_event *next_event)
2450 if (!event->attr.inherit_stat)
2454 * Update the event value, we cannot use perf_event_read()
2455 * because we're in the middle of a context switch and have IRQs
2456 * disabled, which upsets smp_call_function_single(), however
2457 * we know the event must be on the current CPU, therefore we
2458 * don't need to use it.
2460 switch (event->state) {
2461 case PERF_EVENT_STATE_ACTIVE:
2462 event->pmu->read(event);
2465 case PERF_EVENT_STATE_INACTIVE:
2466 update_event_times(event);
2474 * In order to keep per-task stats reliable we need to flip the event
2475 * values when we flip the contexts.
2477 value = local64_read(&next_event->count);
2478 value = local64_xchg(&event->count, value);
2479 local64_set(&next_event->count, value);
2481 swap(event->total_time_enabled, next_event->total_time_enabled);
2482 swap(event->total_time_running, next_event->total_time_running);
2485 * Since we swizzled the values, update the user visible data too.
2487 perf_event_update_userpage(event);
2488 perf_event_update_userpage(next_event);
2491 static void perf_event_sync_stat(struct perf_event_context *ctx,
2492 struct perf_event_context *next_ctx)
2494 struct perf_event *event, *next_event;
2499 update_context_time(ctx);
2501 event = list_first_entry(&ctx->event_list,
2502 struct perf_event, event_entry);
2504 next_event = list_first_entry(&next_ctx->event_list,
2505 struct perf_event, event_entry);
2507 while (&event->event_entry != &ctx->event_list &&
2508 &next_event->event_entry != &next_ctx->event_list) {
2510 __perf_event_sync_stat(event, next_event);
2512 event = list_next_entry(event, event_entry);
2513 next_event = list_next_entry(next_event, event_entry);
2517 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2518 struct task_struct *next)
2520 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2521 struct perf_event_context *next_ctx;
2522 struct perf_event_context *parent, *next_parent;
2523 struct perf_cpu_context *cpuctx;
2529 cpuctx = __get_cpu_context(ctx);
2530 if (!cpuctx->task_ctx)
2534 next_ctx = next->perf_event_ctxp[ctxn];
2538 parent = rcu_dereference(ctx->parent_ctx);
2539 next_parent = rcu_dereference(next_ctx->parent_ctx);
2541 /* If neither context have a parent context; they cannot be clones. */
2542 if (!parent && !next_parent)
2545 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2547 * Looks like the two contexts are clones, so we might be
2548 * able to optimize the context switch. We lock both
2549 * contexts and check that they are clones under the
2550 * lock (including re-checking that neither has been
2551 * uncloned in the meantime). It doesn't matter which
2552 * order we take the locks because no other cpu could
2553 * be trying to lock both of these tasks.
2555 raw_spin_lock(&ctx->lock);
2556 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2557 if (context_equiv(ctx, next_ctx)) {
2558 WRITE_ONCE(ctx->task, next);
2559 WRITE_ONCE(next_ctx->task, task);
2561 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2564 * RCU_INIT_POINTER here is safe because we've not
2565 * modified the ctx and the above modification of
2566 * ctx->task and ctx->task_ctx_data are immaterial
2567 * since those values are always verified under
2568 * ctx->lock which we're now holding.
2570 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2571 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2575 perf_event_sync_stat(ctx, next_ctx);
2577 raw_spin_unlock(&next_ctx->lock);
2578 raw_spin_unlock(&ctx->lock);
2584 raw_spin_lock(&ctx->lock);
2585 task_ctx_sched_out(cpuctx, ctx);
2586 raw_spin_unlock(&ctx->lock);
2590 void perf_sched_cb_dec(struct pmu *pmu)
2592 this_cpu_dec(perf_sched_cb_usages);
2595 void perf_sched_cb_inc(struct pmu *pmu)
2597 this_cpu_inc(perf_sched_cb_usages);
2601 * This function provides the context switch callback to the lower code
2602 * layer. It is invoked ONLY when the context switch callback is enabled.
2604 static void perf_pmu_sched_task(struct task_struct *prev,
2605 struct task_struct *next,
2608 struct perf_cpu_context *cpuctx;
2610 unsigned long flags;
2615 local_irq_save(flags);
2619 list_for_each_entry_rcu(pmu, &pmus, entry) {
2620 if (pmu->sched_task) {
2621 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2623 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2625 perf_pmu_disable(pmu);
2627 pmu->sched_task(cpuctx->task_ctx, sched_in);
2629 perf_pmu_enable(pmu);
2631 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2637 local_irq_restore(flags);
2640 static void perf_event_switch(struct task_struct *task,
2641 struct task_struct *next_prev, bool sched_in);
2643 #define for_each_task_context_nr(ctxn) \
2644 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2647 * Called from scheduler to remove the events of the current task,
2648 * with interrupts disabled.
2650 * We stop each event and update the event value in event->count.
2652 * This does not protect us against NMI, but disable()
2653 * sets the disabled bit in the control field of event _before_
2654 * accessing the event control register. If a NMI hits, then it will
2655 * not restart the event.
2657 void __perf_event_task_sched_out(struct task_struct *task,
2658 struct task_struct *next)
2662 if (__this_cpu_read(perf_sched_cb_usages))
2663 perf_pmu_sched_task(task, next, false);
2665 if (atomic_read(&nr_switch_events))
2666 perf_event_switch(task, next, false);
2668 for_each_task_context_nr(ctxn)
2669 perf_event_context_sched_out(task, ctxn, next);
2672 * if cgroup events exist on this CPU, then we need
2673 * to check if we have to switch out PMU state.
2674 * cgroup event are system-wide mode only
2676 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2677 perf_cgroup_sched_out(task, next);
2680 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2681 struct perf_event_context *ctx)
2683 if (!cpuctx->task_ctx)
2686 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2689 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2693 * Called with IRQs disabled
2695 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2696 enum event_type_t event_type)
2698 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2702 ctx_pinned_sched_in(struct perf_event_context *ctx,
2703 struct perf_cpu_context *cpuctx)
2705 struct perf_event *event;
2707 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2708 if (event->state <= PERF_EVENT_STATE_OFF)
2710 if (!event_filter_match(event))
2713 /* may need to reset tstamp_enabled */
2714 if (is_cgroup_event(event))
2715 perf_cgroup_mark_enabled(event, ctx);
2717 if (group_can_go_on(event, cpuctx, 1))
2718 group_sched_in(event, cpuctx, ctx);
2721 * If this pinned group hasn't been scheduled,
2722 * put it in error state.
2724 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2725 update_group_times(event);
2726 event->state = PERF_EVENT_STATE_ERROR;
2732 ctx_flexible_sched_in(struct perf_event_context *ctx,
2733 struct perf_cpu_context *cpuctx)
2735 struct perf_event *event;
2738 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2739 /* Ignore events in OFF or ERROR state */
2740 if (event->state <= PERF_EVENT_STATE_OFF)
2743 * Listen to the 'cpu' scheduling filter constraint
2746 if (!event_filter_match(event))
2749 /* may need to reset tstamp_enabled */
2750 if (is_cgroup_event(event))
2751 perf_cgroup_mark_enabled(event, ctx);
2753 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2754 if (group_sched_in(event, cpuctx, ctx))
2761 ctx_sched_in(struct perf_event_context *ctx,
2762 struct perf_cpu_context *cpuctx,
2763 enum event_type_t event_type,
2764 struct task_struct *task)
2766 int is_active = ctx->is_active;
2769 lockdep_assert_held(&ctx->lock);
2771 if (likely(!ctx->nr_events))
2774 ctx->is_active |= event_type;
2777 cpuctx->task_ctx = ctx;
2779 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2783 ctx->timestamp = now;
2784 perf_cgroup_set_timestamp(task, ctx);
2786 * First go through the list and put on any pinned groups
2787 * in order to give them the best chance of going on.
2789 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2790 ctx_pinned_sched_in(ctx, cpuctx);
2792 /* Then walk through the lower prio flexible groups */
2793 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2794 ctx_flexible_sched_in(ctx, cpuctx);
2797 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2798 enum event_type_t event_type,
2799 struct task_struct *task)
2801 struct perf_event_context *ctx = &cpuctx->ctx;
2803 ctx_sched_in(ctx, cpuctx, event_type, task);
2806 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2807 struct task_struct *task)
2809 struct perf_cpu_context *cpuctx;
2811 cpuctx = __get_cpu_context(ctx);
2812 if (cpuctx->task_ctx == ctx)
2815 perf_ctx_lock(cpuctx, ctx);
2816 perf_pmu_disable(ctx->pmu);
2818 * We want to keep the following priority order:
2819 * cpu pinned (that don't need to move), task pinned,
2820 * cpu flexible, task flexible.
2822 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2823 perf_event_sched_in(cpuctx, ctx, task);
2824 perf_pmu_enable(ctx->pmu);
2825 perf_ctx_unlock(cpuctx, ctx);
2829 * Called from scheduler to add the events of the current task
2830 * with interrupts disabled.
2832 * We restore the event value and then enable it.
2834 * This does not protect us against NMI, but enable()
2835 * sets the enabled bit in the control field of event _before_
2836 * accessing the event control register. If a NMI hits, then it will
2837 * keep the event running.
2839 void __perf_event_task_sched_in(struct task_struct *prev,
2840 struct task_struct *task)
2842 struct perf_event_context *ctx;
2846 * If cgroup events exist on this CPU, then we need to check if we have
2847 * to switch in PMU state; cgroup event are system-wide mode only.
2849 * Since cgroup events are CPU events, we must schedule these in before
2850 * we schedule in the task events.
2852 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2853 perf_cgroup_sched_in(prev, task);
2855 for_each_task_context_nr(ctxn) {
2856 ctx = task->perf_event_ctxp[ctxn];
2860 perf_event_context_sched_in(ctx, task);
2863 if (atomic_read(&nr_switch_events))
2864 perf_event_switch(task, prev, true);
2866 if (__this_cpu_read(perf_sched_cb_usages))
2867 perf_pmu_sched_task(prev, task, true);
2870 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2872 u64 frequency = event->attr.sample_freq;
2873 u64 sec = NSEC_PER_SEC;
2874 u64 divisor, dividend;
2876 int count_fls, nsec_fls, frequency_fls, sec_fls;
2878 count_fls = fls64(count);
2879 nsec_fls = fls64(nsec);
2880 frequency_fls = fls64(frequency);
2884 * We got @count in @nsec, with a target of sample_freq HZ
2885 * the target period becomes:
2888 * period = -------------------
2889 * @nsec * sample_freq
2894 * Reduce accuracy by one bit such that @a and @b converge
2895 * to a similar magnitude.
2897 #define REDUCE_FLS(a, b) \
2899 if (a##_fls > b##_fls) { \
2909 * Reduce accuracy until either term fits in a u64, then proceed with
2910 * the other, so that finally we can do a u64/u64 division.
2912 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2913 REDUCE_FLS(nsec, frequency);
2914 REDUCE_FLS(sec, count);
2917 if (count_fls + sec_fls > 64) {
2918 divisor = nsec * frequency;
2920 while (count_fls + sec_fls > 64) {
2921 REDUCE_FLS(count, sec);
2925 dividend = count * sec;
2927 dividend = count * sec;
2929 while (nsec_fls + frequency_fls > 64) {
2930 REDUCE_FLS(nsec, frequency);
2934 divisor = nsec * frequency;
2940 return div64_u64(dividend, divisor);
2943 static DEFINE_PER_CPU(int, perf_throttled_count);
2944 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2946 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2948 struct hw_perf_event *hwc = &event->hw;
2949 s64 period, sample_period;
2952 period = perf_calculate_period(event, nsec, count);
2954 delta = (s64)(period - hwc->sample_period);
2955 delta = (delta + 7) / 8; /* low pass filter */
2957 sample_period = hwc->sample_period + delta;
2962 hwc->sample_period = sample_period;
2964 if (local64_read(&hwc->period_left) > 8*sample_period) {
2966 event->pmu->stop(event, PERF_EF_UPDATE);
2968 local64_set(&hwc->period_left, 0);
2971 event->pmu->start(event, PERF_EF_RELOAD);
2976 * combine freq adjustment with unthrottling to avoid two passes over the
2977 * events. At the same time, make sure, having freq events does not change
2978 * the rate of unthrottling as that would introduce bias.
2980 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2983 struct perf_event *event;
2984 struct hw_perf_event *hwc;
2985 u64 now, period = TICK_NSEC;
2989 * only need to iterate over all events iff:
2990 * - context have events in frequency mode (needs freq adjust)
2991 * - there are events to unthrottle on this cpu
2993 if (!(ctx->nr_freq || needs_unthr))
2996 raw_spin_lock(&ctx->lock);
2997 perf_pmu_disable(ctx->pmu);
2999 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3000 if (event->state != PERF_EVENT_STATE_ACTIVE)
3003 if (!event_filter_match(event))
3006 perf_pmu_disable(event->pmu);
3010 if (hwc->interrupts == MAX_INTERRUPTS) {
3011 hwc->interrupts = 0;
3012 perf_log_throttle(event, 1);
3013 event->pmu->start(event, 0);
3016 if (!event->attr.freq || !event->attr.sample_freq)
3020 * stop the event and update event->count
3022 event->pmu->stop(event, PERF_EF_UPDATE);
3024 now = local64_read(&event->count);
3025 delta = now - hwc->freq_count_stamp;
3026 hwc->freq_count_stamp = now;
3030 * reload only if value has changed
3031 * we have stopped the event so tell that
3032 * to perf_adjust_period() to avoid stopping it
3036 perf_adjust_period(event, period, delta, false);
3038 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3040 perf_pmu_enable(event->pmu);
3043 perf_pmu_enable(ctx->pmu);
3044 raw_spin_unlock(&ctx->lock);
3048 * Round-robin a context's events:
3050 static void rotate_ctx(struct perf_event_context *ctx)
3053 * Rotate the first entry last of non-pinned groups. Rotation might be
3054 * disabled by the inheritance code.
3056 if (!ctx->rotate_disable)
3057 list_rotate_left(&ctx->flexible_groups);
3060 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3062 struct perf_event_context *ctx = NULL;
3065 if (cpuctx->ctx.nr_events) {
3066 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3070 ctx = cpuctx->task_ctx;
3071 if (ctx && ctx->nr_events) {
3072 if (ctx->nr_events != ctx->nr_active)
3079 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3080 perf_pmu_disable(cpuctx->ctx.pmu);
3082 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3084 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3086 rotate_ctx(&cpuctx->ctx);
3090 perf_event_sched_in(cpuctx, ctx, current);
3092 perf_pmu_enable(cpuctx->ctx.pmu);
3093 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3099 #ifdef CONFIG_NO_HZ_FULL
3100 bool perf_event_can_stop_tick(void)
3102 if (atomic_read(&nr_freq_events) ||
3103 __this_cpu_read(perf_throttled_count))
3110 void perf_event_task_tick(void)
3112 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3113 struct perf_event_context *ctx, *tmp;
3116 WARN_ON(!irqs_disabled());
3118 __this_cpu_inc(perf_throttled_seq);
3119 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3121 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3122 perf_adjust_freq_unthr_context(ctx, throttled);
3125 static int event_enable_on_exec(struct perf_event *event,
3126 struct perf_event_context *ctx)
3128 if (!event->attr.enable_on_exec)
3131 event->attr.enable_on_exec = 0;
3132 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3135 __perf_event_mark_enabled(event);
3141 * Enable all of a task's events that have been marked enable-on-exec.
3142 * This expects task == current.
3144 static void perf_event_enable_on_exec(int ctxn)
3146 struct perf_event_context *ctx, *clone_ctx = NULL;
3147 struct perf_cpu_context *cpuctx;
3148 struct perf_event *event;
3149 unsigned long flags;
3152 local_irq_save(flags);
3153 ctx = current->perf_event_ctxp[ctxn];
3154 if (!ctx || !ctx->nr_events)
3157 cpuctx = __get_cpu_context(ctx);
3158 perf_ctx_lock(cpuctx, ctx);
3159 list_for_each_entry(event, &ctx->event_list, event_entry)
3160 enabled |= event_enable_on_exec(event, ctx);
3163 * Unclone and reschedule this context if we enabled any event.
3166 clone_ctx = unclone_ctx(ctx);
3167 ctx_resched(cpuctx, ctx);
3169 perf_ctx_unlock(cpuctx, ctx);
3172 local_irq_restore(flags);
3178 void perf_event_exec(void)
3183 for_each_task_context_nr(ctxn)
3184 perf_event_enable_on_exec(ctxn);
3188 struct perf_read_data {
3189 struct perf_event *event;
3195 * Cross CPU call to read the hardware event
3197 static void __perf_event_read(void *info)
3199 struct perf_read_data *data = info;
3200 struct perf_event *sub, *event = data->event;
3201 struct perf_event_context *ctx = event->ctx;
3202 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3203 struct pmu *pmu = event->pmu;
3206 * If this is a task context, we need to check whether it is
3207 * the current task context of this cpu. If not it has been
3208 * scheduled out before the smp call arrived. In that case
3209 * event->count would have been updated to a recent sample
3210 * when the event was scheduled out.
3212 if (ctx->task && cpuctx->task_ctx != ctx)
3215 raw_spin_lock(&ctx->lock);
3216 if (ctx->is_active) {
3217 update_context_time(ctx);
3218 update_cgrp_time_from_event(event);
3221 update_event_times(event);
3222 if (event->state != PERF_EVENT_STATE_ACTIVE)
3231 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3235 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3236 update_event_times(sub);
3237 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3239 * Use sibling's PMU rather than @event's since
3240 * sibling could be on different (eg: software) PMU.
3242 sub->pmu->read(sub);
3246 data->ret = pmu->commit_txn(pmu);
3249 raw_spin_unlock(&ctx->lock);
3252 static inline u64 perf_event_count(struct perf_event *event)
3254 if (event->pmu->count)
3255 return event->pmu->count(event);
3257 return __perf_event_count(event);
3261 * NMI-safe method to read a local event, that is an event that
3263 * - either for the current task, or for this CPU
3264 * - does not have inherit set, for inherited task events
3265 * will not be local and we cannot read them atomically
3266 * - must not have a pmu::count method
3268 u64 perf_event_read_local(struct perf_event *event)
3270 unsigned long flags;
3274 * Disabling interrupts avoids all counter scheduling (context
3275 * switches, timer based rotation and IPIs).
3277 local_irq_save(flags);
3279 /* If this is a per-task event, it must be for current */
3280 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3281 event->hw.target != current);
3283 /* If this is a per-CPU event, it must be for this CPU */
3284 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3285 event->cpu != smp_processor_id());
3288 * It must not be an event with inherit set, we cannot read
3289 * all child counters from atomic context.
3291 WARN_ON_ONCE(event->attr.inherit);
3294 * It must not have a pmu::count method, those are not
3297 WARN_ON_ONCE(event->pmu->count);
3300 * If the event is currently on this CPU, its either a per-task event,
3301 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3304 if (event->oncpu == smp_processor_id())
3305 event->pmu->read(event);
3307 val = local64_read(&event->count);
3308 local_irq_restore(flags);
3313 static int perf_event_read(struct perf_event *event, bool group)
3318 * If event is enabled and currently active on a CPU, update the
3319 * value in the event structure:
3321 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3322 struct perf_read_data data = {
3327 smp_call_function_single(event->oncpu,
3328 __perf_event_read, &data, 1);
3330 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3331 struct perf_event_context *ctx = event->ctx;
3332 unsigned long flags;
3334 raw_spin_lock_irqsave(&ctx->lock, flags);
3336 * may read while context is not active
3337 * (e.g., thread is blocked), in that case
3338 * we cannot update context time
3340 if (ctx->is_active) {
3341 update_context_time(ctx);
3342 update_cgrp_time_from_event(event);
3345 update_group_times(event);
3347 update_event_times(event);
3348 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3355 * Initialize the perf_event context in a task_struct:
3357 static void __perf_event_init_context(struct perf_event_context *ctx)
3359 raw_spin_lock_init(&ctx->lock);
3360 mutex_init(&ctx->mutex);
3361 INIT_LIST_HEAD(&ctx->active_ctx_list);
3362 INIT_LIST_HEAD(&ctx->pinned_groups);
3363 INIT_LIST_HEAD(&ctx->flexible_groups);
3364 INIT_LIST_HEAD(&ctx->event_list);
3365 atomic_set(&ctx->refcount, 1);
3366 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3369 static struct perf_event_context *
3370 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3372 struct perf_event_context *ctx;
3374 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3378 __perf_event_init_context(ctx);
3381 get_task_struct(task);
3388 static struct task_struct *
3389 find_lively_task_by_vpid(pid_t vpid)
3391 struct task_struct *task;
3398 task = find_task_by_vpid(vpid);
3400 get_task_struct(task);
3404 return ERR_PTR(-ESRCH);
3406 /* Reuse ptrace permission checks for now. */
3408 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3413 put_task_struct(task);
3414 return ERR_PTR(err);
3419 * Returns a matching context with refcount and pincount.
3421 static struct perf_event_context *
3422 find_get_context(struct pmu *pmu, struct task_struct *task,
3423 struct perf_event *event)
3425 struct perf_event_context *ctx, *clone_ctx = NULL;
3426 struct perf_cpu_context *cpuctx;
3427 void *task_ctx_data = NULL;
3428 unsigned long flags;
3430 int cpu = event->cpu;
3433 /* Must be root to operate on a CPU event: */
3434 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3435 return ERR_PTR(-EACCES);
3438 * We could be clever and allow to attach a event to an
3439 * offline CPU and activate it when the CPU comes up, but
3442 if (!cpu_online(cpu))
3443 return ERR_PTR(-ENODEV);
3445 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3454 ctxn = pmu->task_ctx_nr;
3458 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3459 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3460 if (!task_ctx_data) {
3467 ctx = perf_lock_task_context(task, ctxn, &flags);
3469 clone_ctx = unclone_ctx(ctx);
3472 if (task_ctx_data && !ctx->task_ctx_data) {
3473 ctx->task_ctx_data = task_ctx_data;
3474 task_ctx_data = NULL;
3476 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3481 ctx = alloc_perf_context(pmu, task);
3486 if (task_ctx_data) {
3487 ctx->task_ctx_data = task_ctx_data;
3488 task_ctx_data = NULL;
3492 mutex_lock(&task->perf_event_mutex);
3494 * If it has already passed perf_event_exit_task().
3495 * we must see PF_EXITING, it takes this mutex too.
3497 if (task->flags & PF_EXITING)
3499 else if (task->perf_event_ctxp[ctxn])
3504 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3506 mutex_unlock(&task->perf_event_mutex);
3508 if (unlikely(err)) {
3517 kfree(task_ctx_data);
3521 kfree(task_ctx_data);
3522 return ERR_PTR(err);
3525 static void perf_event_free_filter(struct perf_event *event);
3526 static void perf_event_free_bpf_prog(struct perf_event *event);
3528 static void free_event_rcu(struct rcu_head *head)
3530 struct perf_event *event;
3532 event = container_of(head, struct perf_event, rcu_head);
3534 put_pid_ns(event->ns);
3535 perf_event_free_filter(event);
3539 static void ring_buffer_attach(struct perf_event *event,
3540 struct ring_buffer *rb);
3542 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3547 if (is_cgroup_event(event))
3548 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3551 static void unaccount_event(struct perf_event *event)
3558 if (event->attach_state & PERF_ATTACH_TASK)
3560 if (event->attr.mmap || event->attr.mmap_data)
3561 atomic_dec(&nr_mmap_events);
3562 if (event->attr.comm)
3563 atomic_dec(&nr_comm_events);
3564 if (event->attr.task)
3565 atomic_dec(&nr_task_events);
3566 if (event->attr.freq)
3567 atomic_dec(&nr_freq_events);
3568 if (event->attr.context_switch) {
3570 atomic_dec(&nr_switch_events);
3572 if (is_cgroup_event(event))
3574 if (has_branch_stack(event))
3578 static_key_slow_dec_deferred(&perf_sched_events);
3580 unaccount_event_cpu(event, event->cpu);
3584 * The following implement mutual exclusion of events on "exclusive" pmus
3585 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3586 * at a time, so we disallow creating events that might conflict, namely:
3588 * 1) cpu-wide events in the presence of per-task events,
3589 * 2) per-task events in the presence of cpu-wide events,
3590 * 3) two matching events on the same context.
3592 * The former two cases are handled in the allocation path (perf_event_alloc(),
3593 * _free_event()), the latter -- before the first perf_install_in_context().
3595 static int exclusive_event_init(struct perf_event *event)
3597 struct pmu *pmu = event->pmu;
3599 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3603 * Prevent co-existence of per-task and cpu-wide events on the
3604 * same exclusive pmu.
3606 * Negative pmu::exclusive_cnt means there are cpu-wide
3607 * events on this "exclusive" pmu, positive means there are
3610 * Since this is called in perf_event_alloc() path, event::ctx
3611 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3612 * to mean "per-task event", because unlike other attach states it
3613 * never gets cleared.
3615 if (event->attach_state & PERF_ATTACH_TASK) {
3616 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3619 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3626 static void exclusive_event_destroy(struct perf_event *event)
3628 struct pmu *pmu = event->pmu;
3630 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3633 /* see comment in exclusive_event_init() */
3634 if (event->attach_state & PERF_ATTACH_TASK)
3635 atomic_dec(&pmu->exclusive_cnt);
3637 atomic_inc(&pmu->exclusive_cnt);
3640 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3642 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3643 (e1->cpu == e2->cpu ||
3650 /* Called under the same ctx::mutex as perf_install_in_context() */
3651 static bool exclusive_event_installable(struct perf_event *event,
3652 struct perf_event_context *ctx)
3654 struct perf_event *iter_event;
3655 struct pmu *pmu = event->pmu;
3657 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3660 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3661 if (exclusive_event_match(iter_event, event))
3668 static void _free_event(struct perf_event *event)
3670 irq_work_sync(&event->pending);
3672 unaccount_event(event);
3676 * Can happen when we close an event with re-directed output.
3678 * Since we have a 0 refcount, perf_mmap_close() will skip
3679 * over us; possibly making our ring_buffer_put() the last.
3681 mutex_lock(&event->mmap_mutex);
3682 ring_buffer_attach(event, NULL);
3683 mutex_unlock(&event->mmap_mutex);
3686 if (is_cgroup_event(event))
3687 perf_detach_cgroup(event);
3689 if (!event->parent) {
3690 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3691 put_callchain_buffers();
3694 perf_event_free_bpf_prog(event);
3697 event->destroy(event);
3700 put_ctx(event->ctx);
3703 exclusive_event_destroy(event);
3704 module_put(event->pmu->module);
3707 call_rcu(&event->rcu_head, free_event_rcu);
3711 * Used to free events which have a known refcount of 1, such as in error paths
3712 * where the event isn't exposed yet and inherited events.
3714 static void free_event(struct perf_event *event)
3716 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3717 "unexpected event refcount: %ld; ptr=%p\n",
3718 atomic_long_read(&event->refcount), event)) {
3719 /* leak to avoid use-after-free */
3727 * Remove user event from the owner task.
3729 static void perf_remove_from_owner(struct perf_event *event)
3731 struct task_struct *owner;
3734 owner = ACCESS_ONCE(event->owner);
3736 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3737 * !owner it means the list deletion is complete and we can indeed
3738 * free this event, otherwise we need to serialize on
3739 * owner->perf_event_mutex.
3741 smp_read_barrier_depends();
3744 * Since delayed_put_task_struct() also drops the last
3745 * task reference we can safely take a new reference
3746 * while holding the rcu_read_lock().
3748 get_task_struct(owner);
3754 * If we're here through perf_event_exit_task() we're already
3755 * holding ctx->mutex which would be an inversion wrt. the
3756 * normal lock order.
3758 * However we can safely take this lock because its the child
3761 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3764 * We have to re-check the event->owner field, if it is cleared
3765 * we raced with perf_event_exit_task(), acquiring the mutex
3766 * ensured they're done, and we can proceed with freeing the
3770 list_del_init(&event->owner_entry);
3771 mutex_unlock(&owner->perf_event_mutex);
3772 put_task_struct(owner);
3776 static void put_event(struct perf_event *event)
3778 struct perf_event_context *ctx;
3780 if (!atomic_long_dec_and_test(&event->refcount))
3783 if (!is_kernel_event(event))
3784 perf_remove_from_owner(event);
3787 * There are two ways this annotation is useful:
3789 * 1) there is a lock recursion from perf_event_exit_task
3790 * see the comment there.
3792 * 2) there is a lock-inversion with mmap_sem through
3793 * perf_read_group(), which takes faults while
3794 * holding ctx->mutex, however this is called after
3795 * the last filedesc died, so there is no possibility
3796 * to trigger the AB-BA case.
3798 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3799 WARN_ON_ONCE(ctx->parent_ctx);
3800 perf_remove_from_context(event, true);
3801 perf_event_ctx_unlock(event, ctx);
3806 int perf_event_release_kernel(struct perf_event *event)
3811 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3814 * Called when the last reference to the file is gone.
3816 static int perf_release(struct inode *inode, struct file *file)
3818 put_event(file->private_data);
3823 * Remove all orphanes events from the context.
3825 static void orphans_remove_work(struct work_struct *work)
3827 struct perf_event_context *ctx;
3828 struct perf_event *event, *tmp;
3830 ctx = container_of(work, struct perf_event_context,
3831 orphans_remove.work);
3833 mutex_lock(&ctx->mutex);
3834 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3835 struct perf_event *parent_event = event->parent;
3837 if (!is_orphaned_child(event))
3840 perf_remove_from_context(event, true);
3842 mutex_lock(&parent_event->child_mutex);
3843 list_del_init(&event->child_list);
3844 mutex_unlock(&parent_event->child_mutex);
3847 put_event(parent_event);
3850 raw_spin_lock_irq(&ctx->lock);
3851 ctx->orphans_remove_sched = false;
3852 raw_spin_unlock_irq(&ctx->lock);
3853 mutex_unlock(&ctx->mutex);
3858 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3860 struct perf_event *child;
3866 mutex_lock(&event->child_mutex);
3868 (void)perf_event_read(event, false);
3869 total += perf_event_count(event);
3871 *enabled += event->total_time_enabled +
3872 atomic64_read(&event->child_total_time_enabled);
3873 *running += event->total_time_running +
3874 atomic64_read(&event->child_total_time_running);
3876 list_for_each_entry(child, &event->child_list, child_list) {
3877 (void)perf_event_read(child, false);
3878 total += perf_event_count(child);
3879 *enabled += child->total_time_enabled;
3880 *running += child->total_time_running;
3882 mutex_unlock(&event->child_mutex);
3886 EXPORT_SYMBOL_GPL(perf_event_read_value);
3888 static int __perf_read_group_add(struct perf_event *leader,
3889 u64 read_format, u64 *values)
3891 struct perf_event *sub;
3892 int n = 1; /* skip @nr */
3895 ret = perf_event_read(leader, true);
3900 * Since we co-schedule groups, {enabled,running} times of siblings
3901 * will be identical to those of the leader, so we only publish one
3904 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3905 values[n++] += leader->total_time_enabled +
3906 atomic64_read(&leader->child_total_time_enabled);
3909 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3910 values[n++] += leader->total_time_running +
3911 atomic64_read(&leader->child_total_time_running);
3915 * Write {count,id} tuples for every sibling.
3917 values[n++] += perf_event_count(leader);
3918 if (read_format & PERF_FORMAT_ID)
3919 values[n++] = primary_event_id(leader);
3921 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3922 values[n++] += perf_event_count(sub);
3923 if (read_format & PERF_FORMAT_ID)
3924 values[n++] = primary_event_id(sub);
3930 static int perf_read_group(struct perf_event *event,
3931 u64 read_format, char __user *buf)
3933 struct perf_event *leader = event->group_leader, *child;
3934 struct perf_event_context *ctx = leader->ctx;
3938 lockdep_assert_held(&ctx->mutex);
3940 values = kzalloc(event->read_size, GFP_KERNEL);
3944 values[0] = 1 + leader->nr_siblings;
3947 * By locking the child_mutex of the leader we effectively
3948 * lock the child list of all siblings.. XXX explain how.
3950 mutex_lock(&leader->child_mutex);
3952 ret = __perf_read_group_add(leader, read_format, values);
3956 list_for_each_entry(child, &leader->child_list, child_list) {
3957 ret = __perf_read_group_add(child, read_format, values);
3962 mutex_unlock(&leader->child_mutex);
3964 ret = event->read_size;
3965 if (copy_to_user(buf, values, event->read_size))
3970 mutex_unlock(&leader->child_mutex);
3976 static int perf_read_one(struct perf_event *event,
3977 u64 read_format, char __user *buf)
3979 u64 enabled, running;
3983 values[n++] = perf_event_read_value(event, &enabled, &running);
3984 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3985 values[n++] = enabled;
3986 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3987 values[n++] = running;
3988 if (read_format & PERF_FORMAT_ID)
3989 values[n++] = primary_event_id(event);
3991 if (copy_to_user(buf, values, n * sizeof(u64)))
3994 return n * sizeof(u64);
3997 static bool is_event_hup(struct perf_event *event)
4001 if (event->state != PERF_EVENT_STATE_EXIT)
4004 mutex_lock(&event->child_mutex);
4005 no_children = list_empty(&event->child_list);
4006 mutex_unlock(&event->child_mutex);
4011 * Read the performance event - simple non blocking version for now
4014 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4016 u64 read_format = event->attr.read_format;
4020 * Return end-of-file for a read on a event that is in
4021 * error state (i.e. because it was pinned but it couldn't be
4022 * scheduled on to the CPU at some point).
4024 if (event->state == PERF_EVENT_STATE_ERROR)
4027 if (count < event->read_size)
4030 WARN_ON_ONCE(event->ctx->parent_ctx);
4031 if (read_format & PERF_FORMAT_GROUP)
4032 ret = perf_read_group(event, read_format, buf);
4034 ret = perf_read_one(event, read_format, buf);
4040 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4042 struct perf_event *event = file->private_data;
4043 struct perf_event_context *ctx;
4046 ctx = perf_event_ctx_lock(event);
4047 ret = __perf_read(event, buf, count);
4048 perf_event_ctx_unlock(event, ctx);
4053 static unsigned int perf_poll(struct file *file, poll_table *wait)
4055 struct perf_event *event = file->private_data;
4056 struct ring_buffer *rb;
4057 unsigned int events = POLLHUP;
4059 poll_wait(file, &event->waitq, wait);
4061 if (is_event_hup(event))
4065 * Pin the event->rb by taking event->mmap_mutex; otherwise
4066 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4068 mutex_lock(&event->mmap_mutex);
4071 events = atomic_xchg(&rb->poll, 0);
4072 mutex_unlock(&event->mmap_mutex);
4076 static void _perf_event_reset(struct perf_event *event)
4078 (void)perf_event_read(event, false);
4079 local64_set(&event->count, 0);
4080 perf_event_update_userpage(event);
4084 * Holding the top-level event's child_mutex means that any
4085 * descendant process that has inherited this event will block
4086 * in sync_child_event if it goes to exit, thus satisfying the
4087 * task existence requirements of perf_event_enable/disable.
4089 static void perf_event_for_each_child(struct perf_event *event,
4090 void (*func)(struct perf_event *))
4092 struct perf_event *child;
4094 WARN_ON_ONCE(event->ctx->parent_ctx);
4096 mutex_lock(&event->child_mutex);
4098 list_for_each_entry(child, &event->child_list, child_list)
4100 mutex_unlock(&event->child_mutex);
4103 static void perf_event_for_each(struct perf_event *event,
4104 void (*func)(struct perf_event *))
4106 struct perf_event_context *ctx = event->ctx;
4107 struct perf_event *sibling;
4109 lockdep_assert_held(&ctx->mutex);
4111 event = event->group_leader;
4113 perf_event_for_each_child(event, func);
4114 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4115 perf_event_for_each_child(sibling, func);
4118 static void __perf_event_period(struct perf_event *event,
4119 struct perf_cpu_context *cpuctx,
4120 struct perf_event_context *ctx,
4123 u64 value = *((u64 *)info);
4126 if (event->attr.freq) {
4127 event->attr.sample_freq = value;
4129 event->attr.sample_period = value;
4130 event->hw.sample_period = value;
4133 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4135 perf_pmu_disable(ctx->pmu);
4136 event->pmu->stop(event, PERF_EF_UPDATE);
4139 local64_set(&event->hw.period_left, 0);
4142 event->pmu->start(event, PERF_EF_RELOAD);
4143 perf_pmu_enable(ctx->pmu);
4147 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4151 if (!is_sampling_event(event))
4154 if (copy_from_user(&value, arg, sizeof(value)))
4160 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4163 event_function_call(event, __perf_event_period, &value);
4168 static const struct file_operations perf_fops;
4170 static inline int perf_fget_light(int fd, struct fd *p)
4172 struct fd f = fdget(fd);
4176 if (f.file->f_op != &perf_fops) {
4184 static int perf_event_set_output(struct perf_event *event,
4185 struct perf_event *output_event);
4186 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4187 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4189 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4191 void (*func)(struct perf_event *);
4195 case PERF_EVENT_IOC_ENABLE:
4196 func = _perf_event_enable;
4198 case PERF_EVENT_IOC_DISABLE:
4199 func = _perf_event_disable;
4201 case PERF_EVENT_IOC_RESET:
4202 func = _perf_event_reset;
4205 case PERF_EVENT_IOC_REFRESH:
4206 return _perf_event_refresh(event, arg);
4208 case PERF_EVENT_IOC_PERIOD:
4209 return perf_event_period(event, (u64 __user *)arg);
4211 case PERF_EVENT_IOC_ID:
4213 u64 id = primary_event_id(event);
4215 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4220 case PERF_EVENT_IOC_SET_OUTPUT:
4224 struct perf_event *output_event;
4226 ret = perf_fget_light(arg, &output);
4229 output_event = output.file->private_data;
4230 ret = perf_event_set_output(event, output_event);
4233 ret = perf_event_set_output(event, NULL);
4238 case PERF_EVENT_IOC_SET_FILTER:
4239 return perf_event_set_filter(event, (void __user *)arg);
4241 case PERF_EVENT_IOC_SET_BPF:
4242 return perf_event_set_bpf_prog(event, arg);
4248 if (flags & PERF_IOC_FLAG_GROUP)
4249 perf_event_for_each(event, func);
4251 perf_event_for_each_child(event, func);
4256 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4258 struct perf_event *event = file->private_data;
4259 struct perf_event_context *ctx;
4262 ctx = perf_event_ctx_lock(event);
4263 ret = _perf_ioctl(event, cmd, arg);
4264 perf_event_ctx_unlock(event, ctx);
4269 #ifdef CONFIG_COMPAT
4270 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4273 switch (_IOC_NR(cmd)) {
4274 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4275 case _IOC_NR(PERF_EVENT_IOC_ID):
4276 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4277 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4278 cmd &= ~IOCSIZE_MASK;
4279 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4283 return perf_ioctl(file, cmd, arg);
4286 # define perf_compat_ioctl NULL
4289 int perf_event_task_enable(void)
4291 struct perf_event_context *ctx;
4292 struct perf_event *event;
4294 mutex_lock(¤t->perf_event_mutex);
4295 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4296 ctx = perf_event_ctx_lock(event);
4297 perf_event_for_each_child(event, _perf_event_enable);
4298 perf_event_ctx_unlock(event, ctx);
4300 mutex_unlock(¤t->perf_event_mutex);
4305 int perf_event_task_disable(void)
4307 struct perf_event_context *ctx;
4308 struct perf_event *event;
4310 mutex_lock(¤t->perf_event_mutex);
4311 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4312 ctx = perf_event_ctx_lock(event);
4313 perf_event_for_each_child(event, _perf_event_disable);
4314 perf_event_ctx_unlock(event, ctx);
4316 mutex_unlock(¤t->perf_event_mutex);
4321 static int perf_event_index(struct perf_event *event)
4323 if (event->hw.state & PERF_HES_STOPPED)
4326 if (event->state != PERF_EVENT_STATE_ACTIVE)
4329 return event->pmu->event_idx(event);
4332 static void calc_timer_values(struct perf_event *event,
4339 *now = perf_clock();
4340 ctx_time = event->shadow_ctx_time + *now;
4341 *enabled = ctx_time - event->tstamp_enabled;
4342 *running = ctx_time - event->tstamp_running;
4345 static void perf_event_init_userpage(struct perf_event *event)
4347 struct perf_event_mmap_page *userpg;
4348 struct ring_buffer *rb;
4351 rb = rcu_dereference(event->rb);
4355 userpg = rb->user_page;
4357 /* Allow new userspace to detect that bit 0 is deprecated */
4358 userpg->cap_bit0_is_deprecated = 1;
4359 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4360 userpg->data_offset = PAGE_SIZE;
4361 userpg->data_size = perf_data_size(rb);
4367 void __weak arch_perf_update_userpage(
4368 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4373 * Callers need to ensure there can be no nesting of this function, otherwise
4374 * the seqlock logic goes bad. We can not serialize this because the arch
4375 * code calls this from NMI context.
4377 void perf_event_update_userpage(struct perf_event *event)
4379 struct perf_event_mmap_page *userpg;
4380 struct ring_buffer *rb;
4381 u64 enabled, running, now;
4384 rb = rcu_dereference(event->rb);
4389 * compute total_time_enabled, total_time_running
4390 * based on snapshot values taken when the event
4391 * was last scheduled in.
4393 * we cannot simply called update_context_time()
4394 * because of locking issue as we can be called in
4397 calc_timer_values(event, &now, &enabled, &running);
4399 userpg = rb->user_page;
4401 * Disable preemption so as to not let the corresponding user-space
4402 * spin too long if we get preempted.
4407 userpg->index = perf_event_index(event);
4408 userpg->offset = perf_event_count(event);
4410 userpg->offset -= local64_read(&event->hw.prev_count);
4412 userpg->time_enabled = enabled +
4413 atomic64_read(&event->child_total_time_enabled);
4415 userpg->time_running = running +
4416 atomic64_read(&event->child_total_time_running);
4418 arch_perf_update_userpage(event, userpg, now);
4427 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4429 struct perf_event *event = vma->vm_file->private_data;
4430 struct ring_buffer *rb;
4431 int ret = VM_FAULT_SIGBUS;
4433 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4434 if (vmf->pgoff == 0)
4440 rb = rcu_dereference(event->rb);
4444 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4447 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4451 get_page(vmf->page);
4452 vmf->page->mapping = vma->vm_file->f_mapping;
4453 vmf->page->index = vmf->pgoff;
4462 static void ring_buffer_attach(struct perf_event *event,
4463 struct ring_buffer *rb)
4465 struct ring_buffer *old_rb = NULL;
4466 unsigned long flags;
4470 * Should be impossible, we set this when removing
4471 * event->rb_entry and wait/clear when adding event->rb_entry.
4473 WARN_ON_ONCE(event->rcu_pending);
4476 spin_lock_irqsave(&old_rb->event_lock, flags);
4477 list_del_rcu(&event->rb_entry);
4478 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4480 event->rcu_batches = get_state_synchronize_rcu();
4481 event->rcu_pending = 1;
4485 if (event->rcu_pending) {
4486 cond_synchronize_rcu(event->rcu_batches);
4487 event->rcu_pending = 0;
4490 spin_lock_irqsave(&rb->event_lock, flags);
4491 list_add_rcu(&event->rb_entry, &rb->event_list);
4492 spin_unlock_irqrestore(&rb->event_lock, flags);
4495 rcu_assign_pointer(event->rb, rb);
4498 ring_buffer_put(old_rb);
4500 * Since we detached before setting the new rb, so that we
4501 * could attach the new rb, we could have missed a wakeup.
4504 wake_up_all(&event->waitq);
4508 static void ring_buffer_wakeup(struct perf_event *event)
4510 struct ring_buffer *rb;
4513 rb = rcu_dereference(event->rb);
4515 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4516 wake_up_all(&event->waitq);
4521 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4523 struct ring_buffer *rb;
4526 rb = rcu_dereference(event->rb);
4528 if (!atomic_inc_not_zero(&rb->refcount))
4536 void ring_buffer_put(struct ring_buffer *rb)
4538 if (!atomic_dec_and_test(&rb->refcount))
4541 WARN_ON_ONCE(!list_empty(&rb->event_list));
4543 call_rcu(&rb->rcu_head, rb_free_rcu);
4546 static void perf_mmap_open(struct vm_area_struct *vma)
4548 struct perf_event *event = vma->vm_file->private_data;
4550 atomic_inc(&event->mmap_count);
4551 atomic_inc(&event->rb->mmap_count);
4554 atomic_inc(&event->rb->aux_mmap_count);
4556 if (event->pmu->event_mapped)
4557 event->pmu->event_mapped(event);
4561 * A buffer can be mmap()ed multiple times; either directly through the same
4562 * event, or through other events by use of perf_event_set_output().
4564 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4565 * the buffer here, where we still have a VM context. This means we need
4566 * to detach all events redirecting to us.
4568 static void perf_mmap_close(struct vm_area_struct *vma)
4570 struct perf_event *event = vma->vm_file->private_data;
4572 struct ring_buffer *rb = ring_buffer_get(event);
4573 struct user_struct *mmap_user = rb->mmap_user;
4574 int mmap_locked = rb->mmap_locked;
4575 unsigned long size = perf_data_size(rb);
4577 if (event->pmu->event_unmapped)
4578 event->pmu->event_unmapped(event);
4581 * rb->aux_mmap_count will always drop before rb->mmap_count and
4582 * event->mmap_count, so it is ok to use event->mmap_mutex to
4583 * serialize with perf_mmap here.
4585 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4586 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4587 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4588 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4591 mutex_unlock(&event->mmap_mutex);
4594 atomic_dec(&rb->mmap_count);
4596 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4599 ring_buffer_attach(event, NULL);
4600 mutex_unlock(&event->mmap_mutex);
4602 /* If there's still other mmap()s of this buffer, we're done. */
4603 if (atomic_read(&rb->mmap_count))
4607 * No other mmap()s, detach from all other events that might redirect
4608 * into the now unreachable buffer. Somewhat complicated by the
4609 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4613 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4614 if (!atomic_long_inc_not_zero(&event->refcount)) {
4616 * This event is en-route to free_event() which will
4617 * detach it and remove it from the list.
4623 mutex_lock(&event->mmap_mutex);
4625 * Check we didn't race with perf_event_set_output() which can
4626 * swizzle the rb from under us while we were waiting to
4627 * acquire mmap_mutex.
4629 * If we find a different rb; ignore this event, a next
4630 * iteration will no longer find it on the list. We have to
4631 * still restart the iteration to make sure we're not now
4632 * iterating the wrong list.
4634 if (event->rb == rb)
4635 ring_buffer_attach(event, NULL);
4637 mutex_unlock(&event->mmap_mutex);
4641 * Restart the iteration; either we're on the wrong list or
4642 * destroyed its integrity by doing a deletion.
4649 * It could be there's still a few 0-ref events on the list; they'll
4650 * get cleaned up by free_event() -- they'll also still have their
4651 * ref on the rb and will free it whenever they are done with it.
4653 * Aside from that, this buffer is 'fully' detached and unmapped,
4654 * undo the VM accounting.
4657 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4658 vma->vm_mm->pinned_vm -= mmap_locked;
4659 free_uid(mmap_user);
4662 ring_buffer_put(rb); /* could be last */
4665 static const struct vm_operations_struct perf_mmap_vmops = {
4666 .open = perf_mmap_open,
4667 .close = perf_mmap_close, /* non mergable */
4668 .fault = perf_mmap_fault,
4669 .page_mkwrite = perf_mmap_fault,
4672 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4674 struct perf_event *event = file->private_data;
4675 unsigned long user_locked, user_lock_limit;
4676 struct user_struct *user = current_user();
4677 unsigned long locked, lock_limit;
4678 struct ring_buffer *rb = NULL;
4679 unsigned long vma_size;
4680 unsigned long nr_pages;
4681 long user_extra = 0, extra = 0;
4682 int ret = 0, flags = 0;
4685 * Don't allow mmap() of inherited per-task counters. This would
4686 * create a performance issue due to all children writing to the
4689 if (event->cpu == -1 && event->attr.inherit)
4692 if (!(vma->vm_flags & VM_SHARED))
4695 vma_size = vma->vm_end - vma->vm_start;
4697 if (vma->vm_pgoff == 0) {
4698 nr_pages = (vma_size / PAGE_SIZE) - 1;
4701 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4702 * mapped, all subsequent mappings should have the same size
4703 * and offset. Must be above the normal perf buffer.
4705 u64 aux_offset, aux_size;
4710 nr_pages = vma_size / PAGE_SIZE;
4712 mutex_lock(&event->mmap_mutex);
4719 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4720 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4722 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4725 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4728 /* already mapped with a different offset */
4729 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4732 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4735 /* already mapped with a different size */
4736 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4739 if (!is_power_of_2(nr_pages))
4742 if (!atomic_inc_not_zero(&rb->mmap_count))
4745 if (rb_has_aux(rb)) {
4746 atomic_inc(&rb->aux_mmap_count);
4751 atomic_set(&rb->aux_mmap_count, 1);
4752 user_extra = nr_pages;
4758 * If we have rb pages ensure they're a power-of-two number, so we
4759 * can do bitmasks instead of modulo.
4761 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4764 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4767 WARN_ON_ONCE(event->ctx->parent_ctx);
4769 mutex_lock(&event->mmap_mutex);
4771 if (event->rb->nr_pages != nr_pages) {
4776 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4778 * Raced against perf_mmap_close() through
4779 * perf_event_set_output(). Try again, hope for better
4782 mutex_unlock(&event->mmap_mutex);
4789 user_extra = nr_pages + 1;
4792 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4795 * Increase the limit linearly with more CPUs:
4797 user_lock_limit *= num_online_cpus();
4799 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4801 if (user_locked > user_lock_limit)
4802 extra = user_locked - user_lock_limit;
4804 lock_limit = rlimit(RLIMIT_MEMLOCK);
4805 lock_limit >>= PAGE_SHIFT;
4806 locked = vma->vm_mm->pinned_vm + extra;
4808 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4809 !capable(CAP_IPC_LOCK)) {
4814 WARN_ON(!rb && event->rb);
4816 if (vma->vm_flags & VM_WRITE)
4817 flags |= RING_BUFFER_WRITABLE;
4820 rb = rb_alloc(nr_pages,
4821 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4829 atomic_set(&rb->mmap_count, 1);
4830 rb->mmap_user = get_current_user();
4831 rb->mmap_locked = extra;
4833 ring_buffer_attach(event, rb);
4835 perf_event_init_userpage(event);
4836 perf_event_update_userpage(event);
4838 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4839 event->attr.aux_watermark, flags);
4841 rb->aux_mmap_locked = extra;
4846 atomic_long_add(user_extra, &user->locked_vm);
4847 vma->vm_mm->pinned_vm += extra;
4849 atomic_inc(&event->mmap_count);
4851 atomic_dec(&rb->mmap_count);
4854 mutex_unlock(&event->mmap_mutex);
4857 * Since pinned accounting is per vm we cannot allow fork() to copy our
4860 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4861 vma->vm_ops = &perf_mmap_vmops;
4863 if (event->pmu->event_mapped)
4864 event->pmu->event_mapped(event);
4869 static int perf_fasync(int fd, struct file *filp, int on)
4871 struct inode *inode = file_inode(filp);
4872 struct perf_event *event = filp->private_data;
4875 mutex_lock(&inode->i_mutex);
4876 retval = fasync_helper(fd, filp, on, &event->fasync);
4877 mutex_unlock(&inode->i_mutex);
4885 static const struct file_operations perf_fops = {
4886 .llseek = no_llseek,
4887 .release = perf_release,
4890 .unlocked_ioctl = perf_ioctl,
4891 .compat_ioctl = perf_compat_ioctl,
4893 .fasync = perf_fasync,
4899 * If there's data, ensure we set the poll() state and publish everything
4900 * to user-space before waking everybody up.
4903 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4905 /* only the parent has fasync state */
4907 event = event->parent;
4908 return &event->fasync;
4911 void perf_event_wakeup(struct perf_event *event)
4913 ring_buffer_wakeup(event);
4915 if (event->pending_kill) {
4916 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4917 event->pending_kill = 0;
4921 static void perf_pending_event(struct irq_work *entry)
4923 struct perf_event *event = container_of(entry,
4924 struct perf_event, pending);
4927 rctx = perf_swevent_get_recursion_context();
4929 * If we 'fail' here, that's OK, it means recursion is already disabled
4930 * and we won't recurse 'further'.
4933 if (event->pending_disable) {
4934 event->pending_disable = 0;
4935 perf_event_disable_local(event);
4938 if (event->pending_wakeup) {
4939 event->pending_wakeup = 0;
4940 perf_event_wakeup(event);
4944 perf_swevent_put_recursion_context(rctx);
4948 * We assume there is only KVM supporting the callbacks.
4949 * Later on, we might change it to a list if there is
4950 * another virtualization implementation supporting the callbacks.
4952 struct perf_guest_info_callbacks *perf_guest_cbs;
4954 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4956 perf_guest_cbs = cbs;
4959 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4961 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4963 perf_guest_cbs = NULL;
4966 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4969 perf_output_sample_regs(struct perf_output_handle *handle,
4970 struct pt_regs *regs, u64 mask)
4974 for_each_set_bit(bit, (const unsigned long *) &mask,
4975 sizeof(mask) * BITS_PER_BYTE) {
4978 val = perf_reg_value(regs, bit);
4979 perf_output_put(handle, val);
4983 static void perf_sample_regs_user(struct perf_regs *regs_user,
4984 struct pt_regs *regs,
4985 struct pt_regs *regs_user_copy)
4987 if (user_mode(regs)) {
4988 regs_user->abi = perf_reg_abi(current);
4989 regs_user->regs = regs;
4990 } else if (current->mm) {
4991 perf_get_regs_user(regs_user, regs, regs_user_copy);
4993 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4994 regs_user->regs = NULL;
4998 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
4999 struct pt_regs *regs)
5001 regs_intr->regs = regs;
5002 regs_intr->abi = perf_reg_abi(current);
5007 * Get remaining task size from user stack pointer.
5009 * It'd be better to take stack vma map and limit this more
5010 * precisly, but there's no way to get it safely under interrupt,
5011 * so using TASK_SIZE as limit.
5013 static u64 perf_ustack_task_size(struct pt_regs *regs)
5015 unsigned long addr = perf_user_stack_pointer(regs);
5017 if (!addr || addr >= TASK_SIZE)
5020 return TASK_SIZE - addr;
5024 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5025 struct pt_regs *regs)
5029 /* No regs, no stack pointer, no dump. */
5034 * Check if we fit in with the requested stack size into the:
5036 * If we don't, we limit the size to the TASK_SIZE.
5038 * - remaining sample size
5039 * If we don't, we customize the stack size to
5040 * fit in to the remaining sample size.
5043 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5044 stack_size = min(stack_size, (u16) task_size);
5046 /* Current header size plus static size and dynamic size. */
5047 header_size += 2 * sizeof(u64);
5049 /* Do we fit in with the current stack dump size? */
5050 if ((u16) (header_size + stack_size) < header_size) {
5052 * If we overflow the maximum size for the sample,
5053 * we customize the stack dump size to fit in.
5055 stack_size = USHRT_MAX - header_size - sizeof(u64);
5056 stack_size = round_up(stack_size, sizeof(u64));
5063 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5064 struct pt_regs *regs)
5066 /* Case of a kernel thread, nothing to dump */
5069 perf_output_put(handle, size);
5078 * - the size requested by user or the best one we can fit
5079 * in to the sample max size
5081 * - user stack dump data
5083 * - the actual dumped size
5087 perf_output_put(handle, dump_size);
5090 sp = perf_user_stack_pointer(regs);
5091 rem = __output_copy_user(handle, (void *) sp, dump_size);
5092 dyn_size = dump_size - rem;
5094 perf_output_skip(handle, rem);
5097 perf_output_put(handle, dyn_size);
5101 static void __perf_event_header__init_id(struct perf_event_header *header,
5102 struct perf_sample_data *data,
5103 struct perf_event *event)
5105 u64 sample_type = event->attr.sample_type;
5107 data->type = sample_type;
5108 header->size += event->id_header_size;
5110 if (sample_type & PERF_SAMPLE_TID) {
5111 /* namespace issues */
5112 data->tid_entry.pid = perf_event_pid(event, current);
5113 data->tid_entry.tid = perf_event_tid(event, current);
5116 if (sample_type & PERF_SAMPLE_TIME)
5117 data->time = perf_event_clock(event);
5119 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5120 data->id = primary_event_id(event);
5122 if (sample_type & PERF_SAMPLE_STREAM_ID)
5123 data->stream_id = event->id;
5125 if (sample_type & PERF_SAMPLE_CPU) {
5126 data->cpu_entry.cpu = raw_smp_processor_id();
5127 data->cpu_entry.reserved = 0;
5131 void perf_event_header__init_id(struct perf_event_header *header,
5132 struct perf_sample_data *data,
5133 struct perf_event *event)
5135 if (event->attr.sample_id_all)
5136 __perf_event_header__init_id(header, data, event);
5139 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5140 struct perf_sample_data *data)
5142 u64 sample_type = data->type;
5144 if (sample_type & PERF_SAMPLE_TID)
5145 perf_output_put(handle, data->tid_entry);
5147 if (sample_type & PERF_SAMPLE_TIME)
5148 perf_output_put(handle, data->time);
5150 if (sample_type & PERF_SAMPLE_ID)
5151 perf_output_put(handle, data->id);
5153 if (sample_type & PERF_SAMPLE_STREAM_ID)
5154 perf_output_put(handle, data->stream_id);
5156 if (sample_type & PERF_SAMPLE_CPU)
5157 perf_output_put(handle, data->cpu_entry);
5159 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5160 perf_output_put(handle, data->id);
5163 void perf_event__output_id_sample(struct perf_event *event,
5164 struct perf_output_handle *handle,
5165 struct perf_sample_data *sample)
5167 if (event->attr.sample_id_all)
5168 __perf_event__output_id_sample(handle, sample);
5171 static void perf_output_read_one(struct perf_output_handle *handle,
5172 struct perf_event *event,
5173 u64 enabled, u64 running)
5175 u64 read_format = event->attr.read_format;
5179 values[n++] = perf_event_count(event);
5180 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5181 values[n++] = enabled +
5182 atomic64_read(&event->child_total_time_enabled);
5184 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5185 values[n++] = running +
5186 atomic64_read(&event->child_total_time_running);
5188 if (read_format & PERF_FORMAT_ID)
5189 values[n++] = primary_event_id(event);
5191 __output_copy(handle, values, n * sizeof(u64));
5195 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5197 static void perf_output_read_group(struct perf_output_handle *handle,
5198 struct perf_event *event,
5199 u64 enabled, u64 running)
5201 struct perf_event *leader = event->group_leader, *sub;
5202 u64 read_format = event->attr.read_format;
5206 values[n++] = 1 + leader->nr_siblings;
5208 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5209 values[n++] = enabled;
5211 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5212 values[n++] = running;
5214 if (leader != event)
5215 leader->pmu->read(leader);
5217 values[n++] = perf_event_count(leader);
5218 if (read_format & PERF_FORMAT_ID)
5219 values[n++] = primary_event_id(leader);
5221 __output_copy(handle, values, n * sizeof(u64));
5223 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5226 if ((sub != event) &&
5227 (sub->state == PERF_EVENT_STATE_ACTIVE))
5228 sub->pmu->read(sub);
5230 values[n++] = perf_event_count(sub);
5231 if (read_format & PERF_FORMAT_ID)
5232 values[n++] = primary_event_id(sub);
5234 __output_copy(handle, values, n * sizeof(u64));
5238 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5239 PERF_FORMAT_TOTAL_TIME_RUNNING)
5241 static void perf_output_read(struct perf_output_handle *handle,
5242 struct perf_event *event)
5244 u64 enabled = 0, running = 0, now;
5245 u64 read_format = event->attr.read_format;
5248 * compute total_time_enabled, total_time_running
5249 * based on snapshot values taken when the event
5250 * was last scheduled in.
5252 * we cannot simply called update_context_time()
5253 * because of locking issue as we are called in
5256 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5257 calc_timer_values(event, &now, &enabled, &running);
5259 if (event->attr.read_format & PERF_FORMAT_GROUP)
5260 perf_output_read_group(handle, event, enabled, running);
5262 perf_output_read_one(handle, event, enabled, running);
5265 void perf_output_sample(struct perf_output_handle *handle,
5266 struct perf_event_header *header,
5267 struct perf_sample_data *data,
5268 struct perf_event *event)
5270 u64 sample_type = data->type;
5272 perf_output_put(handle, *header);
5274 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5275 perf_output_put(handle, data->id);
5277 if (sample_type & PERF_SAMPLE_IP)
5278 perf_output_put(handle, data->ip);
5280 if (sample_type & PERF_SAMPLE_TID)
5281 perf_output_put(handle, data->tid_entry);
5283 if (sample_type & PERF_SAMPLE_TIME)
5284 perf_output_put(handle, data->time);
5286 if (sample_type & PERF_SAMPLE_ADDR)
5287 perf_output_put(handle, data->addr);
5289 if (sample_type & PERF_SAMPLE_ID)
5290 perf_output_put(handle, data->id);
5292 if (sample_type & PERF_SAMPLE_STREAM_ID)
5293 perf_output_put(handle, data->stream_id);
5295 if (sample_type & PERF_SAMPLE_CPU)
5296 perf_output_put(handle, data->cpu_entry);
5298 if (sample_type & PERF_SAMPLE_PERIOD)
5299 perf_output_put(handle, data->period);
5301 if (sample_type & PERF_SAMPLE_READ)
5302 perf_output_read(handle, event);
5304 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5305 if (data->callchain) {
5308 if (data->callchain)
5309 size += data->callchain->nr;
5311 size *= sizeof(u64);
5313 __output_copy(handle, data->callchain, size);
5316 perf_output_put(handle, nr);
5320 if (sample_type & PERF_SAMPLE_RAW) {
5322 u32 raw_size = data->raw->size;
5323 u32 real_size = round_up(raw_size + sizeof(u32),
5324 sizeof(u64)) - sizeof(u32);
5327 perf_output_put(handle, real_size);
5328 __output_copy(handle, data->raw->data, raw_size);
5329 if (real_size - raw_size)
5330 __output_copy(handle, &zero, real_size - raw_size);
5336 .size = sizeof(u32),
5339 perf_output_put(handle, raw);
5343 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5344 if (data->br_stack) {
5347 size = data->br_stack->nr
5348 * sizeof(struct perf_branch_entry);
5350 perf_output_put(handle, data->br_stack->nr);
5351 perf_output_copy(handle, data->br_stack->entries, size);
5354 * we always store at least the value of nr
5357 perf_output_put(handle, nr);
5361 if (sample_type & PERF_SAMPLE_REGS_USER) {
5362 u64 abi = data->regs_user.abi;
5365 * If there are no regs to dump, notice it through
5366 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5368 perf_output_put(handle, abi);
5371 u64 mask = event->attr.sample_regs_user;
5372 perf_output_sample_regs(handle,
5373 data->regs_user.regs,
5378 if (sample_type & PERF_SAMPLE_STACK_USER) {
5379 perf_output_sample_ustack(handle,
5380 data->stack_user_size,
5381 data->regs_user.regs);
5384 if (sample_type & PERF_SAMPLE_WEIGHT)
5385 perf_output_put(handle, data->weight);
5387 if (sample_type & PERF_SAMPLE_DATA_SRC)
5388 perf_output_put(handle, data->data_src.val);
5390 if (sample_type & PERF_SAMPLE_TRANSACTION)
5391 perf_output_put(handle, data->txn);
5393 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5394 u64 abi = data->regs_intr.abi;
5396 * If there are no regs to dump, notice it through
5397 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5399 perf_output_put(handle, abi);
5402 u64 mask = event->attr.sample_regs_intr;
5404 perf_output_sample_regs(handle,
5405 data->regs_intr.regs,
5410 if (!event->attr.watermark) {
5411 int wakeup_events = event->attr.wakeup_events;
5413 if (wakeup_events) {
5414 struct ring_buffer *rb = handle->rb;
5415 int events = local_inc_return(&rb->events);
5417 if (events >= wakeup_events) {
5418 local_sub(wakeup_events, &rb->events);
5419 local_inc(&rb->wakeup);
5425 void perf_prepare_sample(struct perf_event_header *header,
5426 struct perf_sample_data *data,
5427 struct perf_event *event,
5428 struct pt_regs *regs)
5430 u64 sample_type = event->attr.sample_type;
5432 header->type = PERF_RECORD_SAMPLE;
5433 header->size = sizeof(*header) + event->header_size;
5436 header->misc |= perf_misc_flags(regs);
5438 __perf_event_header__init_id(header, data, event);
5440 if (sample_type & PERF_SAMPLE_IP)
5441 data->ip = perf_instruction_pointer(regs);
5443 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5446 data->callchain = perf_callchain(event, regs);
5448 if (data->callchain)
5449 size += data->callchain->nr;
5451 header->size += size * sizeof(u64);
5454 if (sample_type & PERF_SAMPLE_RAW) {
5455 int size = sizeof(u32);
5458 size += data->raw->size;
5460 size += sizeof(u32);
5462 header->size += round_up(size, sizeof(u64));
5465 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5466 int size = sizeof(u64); /* nr */
5467 if (data->br_stack) {
5468 size += data->br_stack->nr
5469 * sizeof(struct perf_branch_entry);
5471 header->size += size;
5474 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5475 perf_sample_regs_user(&data->regs_user, regs,
5476 &data->regs_user_copy);
5478 if (sample_type & PERF_SAMPLE_REGS_USER) {
5479 /* regs dump ABI info */
5480 int size = sizeof(u64);
5482 if (data->regs_user.regs) {
5483 u64 mask = event->attr.sample_regs_user;
5484 size += hweight64(mask) * sizeof(u64);
5487 header->size += size;
5490 if (sample_type & PERF_SAMPLE_STACK_USER) {
5492 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5493 * processed as the last one or have additional check added
5494 * in case new sample type is added, because we could eat
5495 * up the rest of the sample size.
5497 u16 stack_size = event->attr.sample_stack_user;
5498 u16 size = sizeof(u64);
5500 stack_size = perf_sample_ustack_size(stack_size, header->size,
5501 data->regs_user.regs);
5504 * If there is something to dump, add space for the dump
5505 * itself and for the field that tells the dynamic size,
5506 * which is how many have been actually dumped.
5509 size += sizeof(u64) + stack_size;
5511 data->stack_user_size = stack_size;
5512 header->size += size;
5515 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5516 /* regs dump ABI info */
5517 int size = sizeof(u64);
5519 perf_sample_regs_intr(&data->regs_intr, regs);
5521 if (data->regs_intr.regs) {
5522 u64 mask = event->attr.sample_regs_intr;
5524 size += hweight64(mask) * sizeof(u64);
5527 header->size += size;
5531 void perf_event_output(struct perf_event *event,
5532 struct perf_sample_data *data,
5533 struct pt_regs *regs)
5535 struct perf_output_handle handle;
5536 struct perf_event_header header;
5538 /* protect the callchain buffers */
5541 perf_prepare_sample(&header, data, event, regs);
5543 if (perf_output_begin(&handle, event, header.size))
5546 perf_output_sample(&handle, &header, data, event);
5548 perf_output_end(&handle);
5558 struct perf_read_event {
5559 struct perf_event_header header;
5566 perf_event_read_event(struct perf_event *event,
5567 struct task_struct *task)
5569 struct perf_output_handle handle;
5570 struct perf_sample_data sample;
5571 struct perf_read_event read_event = {
5573 .type = PERF_RECORD_READ,
5575 .size = sizeof(read_event) + event->read_size,
5577 .pid = perf_event_pid(event, task),
5578 .tid = perf_event_tid(event, task),
5582 perf_event_header__init_id(&read_event.header, &sample, event);
5583 ret = perf_output_begin(&handle, event, read_event.header.size);
5587 perf_output_put(&handle, read_event);
5588 perf_output_read(&handle, event);
5589 perf_event__output_id_sample(event, &handle, &sample);
5591 perf_output_end(&handle);
5594 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5597 perf_event_aux_ctx(struct perf_event_context *ctx,
5598 perf_event_aux_output_cb output,
5601 struct perf_event *event;
5603 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5604 if (event->state < PERF_EVENT_STATE_INACTIVE)
5606 if (!event_filter_match(event))
5608 output(event, data);
5613 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5614 struct perf_event_context *task_ctx)
5618 perf_event_aux_ctx(task_ctx, output, data);
5624 perf_event_aux(perf_event_aux_output_cb output, void *data,
5625 struct perf_event_context *task_ctx)
5627 struct perf_cpu_context *cpuctx;
5628 struct perf_event_context *ctx;
5633 * If we have task_ctx != NULL we only notify
5634 * the task context itself. The task_ctx is set
5635 * only for EXIT events before releasing task
5639 perf_event_aux_task_ctx(output, data, task_ctx);
5644 list_for_each_entry_rcu(pmu, &pmus, entry) {
5645 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5646 if (cpuctx->unique_pmu != pmu)
5648 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5649 ctxn = pmu->task_ctx_nr;
5652 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5654 perf_event_aux_ctx(ctx, output, data);
5656 put_cpu_ptr(pmu->pmu_cpu_context);
5662 * task tracking -- fork/exit
5664 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5667 struct perf_task_event {
5668 struct task_struct *task;
5669 struct perf_event_context *task_ctx;
5672 struct perf_event_header header;
5682 static int perf_event_task_match(struct perf_event *event)
5684 return event->attr.comm || event->attr.mmap ||
5685 event->attr.mmap2 || event->attr.mmap_data ||
5689 static void perf_event_task_output(struct perf_event *event,
5692 struct perf_task_event *task_event = data;
5693 struct perf_output_handle handle;
5694 struct perf_sample_data sample;
5695 struct task_struct *task = task_event->task;
5696 int ret, size = task_event->event_id.header.size;
5698 if (!perf_event_task_match(event))
5701 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5703 ret = perf_output_begin(&handle, event,
5704 task_event->event_id.header.size);
5708 task_event->event_id.pid = perf_event_pid(event, task);
5709 task_event->event_id.ppid = perf_event_pid(event, current);
5711 task_event->event_id.tid = perf_event_tid(event, task);
5712 task_event->event_id.ptid = perf_event_tid(event, current);
5714 task_event->event_id.time = perf_event_clock(event);
5716 perf_output_put(&handle, task_event->event_id);
5718 perf_event__output_id_sample(event, &handle, &sample);
5720 perf_output_end(&handle);
5722 task_event->event_id.header.size = size;
5725 static void perf_event_task(struct task_struct *task,
5726 struct perf_event_context *task_ctx,
5729 struct perf_task_event task_event;
5731 if (!atomic_read(&nr_comm_events) &&
5732 !atomic_read(&nr_mmap_events) &&
5733 !atomic_read(&nr_task_events))
5736 task_event = (struct perf_task_event){
5738 .task_ctx = task_ctx,
5741 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5743 .size = sizeof(task_event.event_id),
5753 perf_event_aux(perf_event_task_output,
5758 void perf_event_fork(struct task_struct *task)
5760 perf_event_task(task, NULL, 1);
5767 struct perf_comm_event {
5768 struct task_struct *task;
5773 struct perf_event_header header;
5780 static int perf_event_comm_match(struct perf_event *event)
5782 return event->attr.comm;
5785 static void perf_event_comm_output(struct perf_event *event,
5788 struct perf_comm_event *comm_event = data;
5789 struct perf_output_handle handle;
5790 struct perf_sample_data sample;
5791 int size = comm_event->event_id.header.size;
5794 if (!perf_event_comm_match(event))
5797 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5798 ret = perf_output_begin(&handle, event,
5799 comm_event->event_id.header.size);
5804 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5805 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5807 perf_output_put(&handle, comm_event->event_id);
5808 __output_copy(&handle, comm_event->comm,
5809 comm_event->comm_size);
5811 perf_event__output_id_sample(event, &handle, &sample);
5813 perf_output_end(&handle);
5815 comm_event->event_id.header.size = size;
5818 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5820 char comm[TASK_COMM_LEN];
5823 memset(comm, 0, sizeof(comm));
5824 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5825 size = ALIGN(strlen(comm)+1, sizeof(u64));
5827 comm_event->comm = comm;
5828 comm_event->comm_size = size;
5830 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5832 perf_event_aux(perf_event_comm_output,
5837 void perf_event_comm(struct task_struct *task, bool exec)
5839 struct perf_comm_event comm_event;
5841 if (!atomic_read(&nr_comm_events))
5844 comm_event = (struct perf_comm_event){
5850 .type = PERF_RECORD_COMM,
5851 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5859 perf_event_comm_event(&comm_event);
5866 struct perf_mmap_event {
5867 struct vm_area_struct *vma;
5869 const char *file_name;
5877 struct perf_event_header header;
5887 static int perf_event_mmap_match(struct perf_event *event,
5890 struct perf_mmap_event *mmap_event = data;
5891 struct vm_area_struct *vma = mmap_event->vma;
5892 int executable = vma->vm_flags & VM_EXEC;
5894 return (!executable && event->attr.mmap_data) ||
5895 (executable && (event->attr.mmap || event->attr.mmap2));
5898 static void perf_event_mmap_output(struct perf_event *event,
5901 struct perf_mmap_event *mmap_event = data;
5902 struct perf_output_handle handle;
5903 struct perf_sample_data sample;
5904 int size = mmap_event->event_id.header.size;
5907 if (!perf_event_mmap_match(event, data))
5910 if (event->attr.mmap2) {
5911 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5912 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5913 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5914 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5915 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5916 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5917 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5920 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5921 ret = perf_output_begin(&handle, event,
5922 mmap_event->event_id.header.size);
5926 mmap_event->event_id.pid = perf_event_pid(event, current);
5927 mmap_event->event_id.tid = perf_event_tid(event, current);
5929 perf_output_put(&handle, mmap_event->event_id);
5931 if (event->attr.mmap2) {
5932 perf_output_put(&handle, mmap_event->maj);
5933 perf_output_put(&handle, mmap_event->min);
5934 perf_output_put(&handle, mmap_event->ino);
5935 perf_output_put(&handle, mmap_event->ino_generation);
5936 perf_output_put(&handle, mmap_event->prot);
5937 perf_output_put(&handle, mmap_event->flags);
5940 __output_copy(&handle, mmap_event->file_name,
5941 mmap_event->file_size);
5943 perf_event__output_id_sample(event, &handle, &sample);
5945 perf_output_end(&handle);
5947 mmap_event->event_id.header.size = size;
5950 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5952 struct vm_area_struct *vma = mmap_event->vma;
5953 struct file *file = vma->vm_file;
5954 int maj = 0, min = 0;
5955 u64 ino = 0, gen = 0;
5956 u32 prot = 0, flags = 0;
5963 struct inode *inode;
5966 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5972 * d_path() works from the end of the rb backwards, so we
5973 * need to add enough zero bytes after the string to handle
5974 * the 64bit alignment we do later.
5976 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5981 inode = file_inode(vma->vm_file);
5982 dev = inode->i_sb->s_dev;
5984 gen = inode->i_generation;
5988 if (vma->vm_flags & VM_READ)
5990 if (vma->vm_flags & VM_WRITE)
5992 if (vma->vm_flags & VM_EXEC)
5995 if (vma->vm_flags & VM_MAYSHARE)
5998 flags = MAP_PRIVATE;
6000 if (vma->vm_flags & VM_DENYWRITE)
6001 flags |= MAP_DENYWRITE;
6002 if (vma->vm_flags & VM_MAYEXEC)
6003 flags |= MAP_EXECUTABLE;
6004 if (vma->vm_flags & VM_LOCKED)
6005 flags |= MAP_LOCKED;
6006 if (vma->vm_flags & VM_HUGETLB)
6007 flags |= MAP_HUGETLB;
6011 if (vma->vm_ops && vma->vm_ops->name) {
6012 name = (char *) vma->vm_ops->name(vma);
6017 name = (char *)arch_vma_name(vma);
6021 if (vma->vm_start <= vma->vm_mm->start_brk &&
6022 vma->vm_end >= vma->vm_mm->brk) {
6026 if (vma->vm_start <= vma->vm_mm->start_stack &&
6027 vma->vm_end >= vma->vm_mm->start_stack) {
6037 strlcpy(tmp, name, sizeof(tmp));
6041 * Since our buffer works in 8 byte units we need to align our string
6042 * size to a multiple of 8. However, we must guarantee the tail end is
6043 * zero'd out to avoid leaking random bits to userspace.
6045 size = strlen(name)+1;
6046 while (!IS_ALIGNED(size, sizeof(u64)))
6047 name[size++] = '\0';
6049 mmap_event->file_name = name;
6050 mmap_event->file_size = size;
6051 mmap_event->maj = maj;
6052 mmap_event->min = min;
6053 mmap_event->ino = ino;
6054 mmap_event->ino_generation = gen;
6055 mmap_event->prot = prot;
6056 mmap_event->flags = flags;
6058 if (!(vma->vm_flags & VM_EXEC))
6059 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6061 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6063 perf_event_aux(perf_event_mmap_output,
6070 void perf_event_mmap(struct vm_area_struct *vma)
6072 struct perf_mmap_event mmap_event;
6074 if (!atomic_read(&nr_mmap_events))
6077 mmap_event = (struct perf_mmap_event){
6083 .type = PERF_RECORD_MMAP,
6084 .misc = PERF_RECORD_MISC_USER,
6089 .start = vma->vm_start,
6090 .len = vma->vm_end - vma->vm_start,
6091 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6093 /* .maj (attr_mmap2 only) */
6094 /* .min (attr_mmap2 only) */
6095 /* .ino (attr_mmap2 only) */
6096 /* .ino_generation (attr_mmap2 only) */
6097 /* .prot (attr_mmap2 only) */
6098 /* .flags (attr_mmap2 only) */
6101 perf_event_mmap_event(&mmap_event);
6104 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6105 unsigned long size, u64 flags)
6107 struct perf_output_handle handle;
6108 struct perf_sample_data sample;
6109 struct perf_aux_event {
6110 struct perf_event_header header;
6116 .type = PERF_RECORD_AUX,
6118 .size = sizeof(rec),
6126 perf_event_header__init_id(&rec.header, &sample, event);
6127 ret = perf_output_begin(&handle, event, rec.header.size);
6132 perf_output_put(&handle, rec);
6133 perf_event__output_id_sample(event, &handle, &sample);
6135 perf_output_end(&handle);
6139 * Lost/dropped samples logging
6141 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6143 struct perf_output_handle handle;
6144 struct perf_sample_data sample;
6148 struct perf_event_header header;
6150 } lost_samples_event = {
6152 .type = PERF_RECORD_LOST_SAMPLES,
6154 .size = sizeof(lost_samples_event),
6159 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6161 ret = perf_output_begin(&handle, event,
6162 lost_samples_event.header.size);
6166 perf_output_put(&handle, lost_samples_event);
6167 perf_event__output_id_sample(event, &handle, &sample);
6168 perf_output_end(&handle);
6172 * context_switch tracking
6175 struct perf_switch_event {
6176 struct task_struct *task;
6177 struct task_struct *next_prev;
6180 struct perf_event_header header;
6186 static int perf_event_switch_match(struct perf_event *event)
6188 return event->attr.context_switch;
6191 static void perf_event_switch_output(struct perf_event *event, void *data)
6193 struct perf_switch_event *se = data;
6194 struct perf_output_handle handle;
6195 struct perf_sample_data sample;
6198 if (!perf_event_switch_match(event))
6201 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6202 if (event->ctx->task) {
6203 se->event_id.header.type = PERF_RECORD_SWITCH;
6204 se->event_id.header.size = sizeof(se->event_id.header);
6206 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6207 se->event_id.header.size = sizeof(se->event_id);
6208 se->event_id.next_prev_pid =
6209 perf_event_pid(event, se->next_prev);
6210 se->event_id.next_prev_tid =
6211 perf_event_tid(event, se->next_prev);
6214 perf_event_header__init_id(&se->event_id.header, &sample, event);
6216 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6220 if (event->ctx->task)
6221 perf_output_put(&handle, se->event_id.header);
6223 perf_output_put(&handle, se->event_id);
6225 perf_event__output_id_sample(event, &handle, &sample);
6227 perf_output_end(&handle);
6230 static void perf_event_switch(struct task_struct *task,
6231 struct task_struct *next_prev, bool sched_in)
6233 struct perf_switch_event switch_event;
6235 /* N.B. caller checks nr_switch_events != 0 */
6237 switch_event = (struct perf_switch_event){
6239 .next_prev = next_prev,
6243 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6246 /* .next_prev_pid */
6247 /* .next_prev_tid */
6251 perf_event_aux(perf_event_switch_output,
6257 * IRQ throttle logging
6260 static void perf_log_throttle(struct perf_event *event, int enable)
6262 struct perf_output_handle handle;
6263 struct perf_sample_data sample;
6267 struct perf_event_header header;
6271 } throttle_event = {
6273 .type = PERF_RECORD_THROTTLE,
6275 .size = sizeof(throttle_event),
6277 .time = perf_event_clock(event),
6278 .id = primary_event_id(event),
6279 .stream_id = event->id,
6283 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6285 perf_event_header__init_id(&throttle_event.header, &sample, event);
6287 ret = perf_output_begin(&handle, event,
6288 throttle_event.header.size);
6292 perf_output_put(&handle, throttle_event);
6293 perf_event__output_id_sample(event, &handle, &sample);
6294 perf_output_end(&handle);
6297 static void perf_log_itrace_start(struct perf_event *event)
6299 struct perf_output_handle handle;
6300 struct perf_sample_data sample;
6301 struct perf_aux_event {
6302 struct perf_event_header header;
6309 event = event->parent;
6311 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6312 event->hw.itrace_started)
6315 rec.header.type = PERF_RECORD_ITRACE_START;
6316 rec.header.misc = 0;
6317 rec.header.size = sizeof(rec);
6318 rec.pid = perf_event_pid(event, current);
6319 rec.tid = perf_event_tid(event, current);
6321 perf_event_header__init_id(&rec.header, &sample, event);
6322 ret = perf_output_begin(&handle, event, rec.header.size);
6327 perf_output_put(&handle, rec);
6328 perf_event__output_id_sample(event, &handle, &sample);
6330 perf_output_end(&handle);
6334 * Generic event overflow handling, sampling.
6337 static int __perf_event_overflow(struct perf_event *event,
6338 int throttle, struct perf_sample_data *data,
6339 struct pt_regs *regs)
6341 int events = atomic_read(&event->event_limit);
6342 struct hw_perf_event *hwc = &event->hw;
6347 * Non-sampling counters might still use the PMI to fold short
6348 * hardware counters, ignore those.
6350 if (unlikely(!is_sampling_event(event)))
6353 seq = __this_cpu_read(perf_throttled_seq);
6354 if (seq != hwc->interrupts_seq) {
6355 hwc->interrupts_seq = seq;
6356 hwc->interrupts = 1;
6359 if (unlikely(throttle
6360 && hwc->interrupts >= max_samples_per_tick)) {
6361 __this_cpu_inc(perf_throttled_count);
6362 hwc->interrupts = MAX_INTERRUPTS;
6363 perf_log_throttle(event, 0);
6364 tick_nohz_full_kick();
6369 if (event->attr.freq) {
6370 u64 now = perf_clock();
6371 s64 delta = now - hwc->freq_time_stamp;
6373 hwc->freq_time_stamp = now;
6375 if (delta > 0 && delta < 2*TICK_NSEC)
6376 perf_adjust_period(event, delta, hwc->last_period, true);
6380 * XXX event_limit might not quite work as expected on inherited
6384 event->pending_kill = POLL_IN;
6385 if (events && atomic_dec_and_test(&event->event_limit)) {
6387 event->pending_kill = POLL_HUP;
6388 event->pending_disable = 1;
6389 irq_work_queue(&event->pending);
6392 if (event->overflow_handler)
6393 event->overflow_handler(event, data, regs);
6395 perf_event_output(event, data, regs);
6397 if (*perf_event_fasync(event) && event->pending_kill) {
6398 event->pending_wakeup = 1;
6399 irq_work_queue(&event->pending);
6405 int perf_event_overflow(struct perf_event *event,
6406 struct perf_sample_data *data,
6407 struct pt_regs *regs)
6409 return __perf_event_overflow(event, 1, data, regs);
6413 * Generic software event infrastructure
6416 struct swevent_htable {
6417 struct swevent_hlist *swevent_hlist;
6418 struct mutex hlist_mutex;
6421 /* Recursion avoidance in each contexts */
6422 int recursion[PERF_NR_CONTEXTS];
6425 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6428 * We directly increment event->count and keep a second value in
6429 * event->hw.period_left to count intervals. This period event
6430 * is kept in the range [-sample_period, 0] so that we can use the
6434 u64 perf_swevent_set_period(struct perf_event *event)
6436 struct hw_perf_event *hwc = &event->hw;
6437 u64 period = hwc->last_period;
6441 hwc->last_period = hwc->sample_period;
6444 old = val = local64_read(&hwc->period_left);
6448 nr = div64_u64(period + val, period);
6449 offset = nr * period;
6451 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6457 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6458 struct perf_sample_data *data,
6459 struct pt_regs *regs)
6461 struct hw_perf_event *hwc = &event->hw;
6465 overflow = perf_swevent_set_period(event);
6467 if (hwc->interrupts == MAX_INTERRUPTS)
6470 for (; overflow; overflow--) {
6471 if (__perf_event_overflow(event, throttle,
6474 * We inhibit the overflow from happening when
6475 * hwc->interrupts == MAX_INTERRUPTS.
6483 static void perf_swevent_event(struct perf_event *event, u64 nr,
6484 struct perf_sample_data *data,
6485 struct pt_regs *regs)
6487 struct hw_perf_event *hwc = &event->hw;
6489 local64_add(nr, &event->count);
6494 if (!is_sampling_event(event))
6497 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6499 return perf_swevent_overflow(event, 1, data, regs);
6501 data->period = event->hw.last_period;
6503 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6504 return perf_swevent_overflow(event, 1, data, regs);
6506 if (local64_add_negative(nr, &hwc->period_left))
6509 perf_swevent_overflow(event, 0, data, regs);
6512 static int perf_exclude_event(struct perf_event *event,
6513 struct pt_regs *regs)
6515 if (event->hw.state & PERF_HES_STOPPED)
6519 if (event->attr.exclude_user && user_mode(regs))
6522 if (event->attr.exclude_kernel && !user_mode(regs))
6529 static int perf_swevent_match(struct perf_event *event,
6530 enum perf_type_id type,
6532 struct perf_sample_data *data,
6533 struct pt_regs *regs)
6535 if (event->attr.type != type)
6538 if (event->attr.config != event_id)
6541 if (perf_exclude_event(event, regs))
6547 static inline u64 swevent_hash(u64 type, u32 event_id)
6549 u64 val = event_id | (type << 32);
6551 return hash_64(val, SWEVENT_HLIST_BITS);
6554 static inline struct hlist_head *
6555 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6557 u64 hash = swevent_hash(type, event_id);
6559 return &hlist->heads[hash];
6562 /* For the read side: events when they trigger */
6563 static inline struct hlist_head *
6564 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6566 struct swevent_hlist *hlist;
6568 hlist = rcu_dereference(swhash->swevent_hlist);
6572 return __find_swevent_head(hlist, type, event_id);
6575 /* For the event head insertion and removal in the hlist */
6576 static inline struct hlist_head *
6577 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6579 struct swevent_hlist *hlist;
6580 u32 event_id = event->attr.config;
6581 u64 type = event->attr.type;
6584 * Event scheduling is always serialized against hlist allocation
6585 * and release. Which makes the protected version suitable here.
6586 * The context lock guarantees that.
6588 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6589 lockdep_is_held(&event->ctx->lock));
6593 return __find_swevent_head(hlist, type, event_id);
6596 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6598 struct perf_sample_data *data,
6599 struct pt_regs *regs)
6601 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6602 struct perf_event *event;
6603 struct hlist_head *head;
6606 head = find_swevent_head_rcu(swhash, type, event_id);
6610 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6611 if (perf_swevent_match(event, type, event_id, data, regs))
6612 perf_swevent_event(event, nr, data, regs);
6618 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6620 int perf_swevent_get_recursion_context(void)
6622 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6624 return get_recursion_context(swhash->recursion);
6626 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6628 inline void perf_swevent_put_recursion_context(int rctx)
6630 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6632 put_recursion_context(swhash->recursion, rctx);
6635 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6637 struct perf_sample_data data;
6639 if (WARN_ON_ONCE(!regs))
6642 perf_sample_data_init(&data, addr, 0);
6643 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6646 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6650 preempt_disable_notrace();
6651 rctx = perf_swevent_get_recursion_context();
6652 if (unlikely(rctx < 0))
6655 ___perf_sw_event(event_id, nr, regs, addr);
6657 perf_swevent_put_recursion_context(rctx);
6659 preempt_enable_notrace();
6662 static void perf_swevent_read(struct perf_event *event)
6666 static int perf_swevent_add(struct perf_event *event, int flags)
6668 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6669 struct hw_perf_event *hwc = &event->hw;
6670 struct hlist_head *head;
6672 if (is_sampling_event(event)) {
6673 hwc->last_period = hwc->sample_period;
6674 perf_swevent_set_period(event);
6677 hwc->state = !(flags & PERF_EF_START);
6679 head = find_swevent_head(swhash, event);
6680 if (WARN_ON_ONCE(!head))
6683 hlist_add_head_rcu(&event->hlist_entry, head);
6684 perf_event_update_userpage(event);
6689 static void perf_swevent_del(struct perf_event *event, int flags)
6691 hlist_del_rcu(&event->hlist_entry);
6694 static void perf_swevent_start(struct perf_event *event, int flags)
6696 event->hw.state = 0;
6699 static void perf_swevent_stop(struct perf_event *event, int flags)
6701 event->hw.state = PERF_HES_STOPPED;
6704 /* Deref the hlist from the update side */
6705 static inline struct swevent_hlist *
6706 swevent_hlist_deref(struct swevent_htable *swhash)
6708 return rcu_dereference_protected(swhash->swevent_hlist,
6709 lockdep_is_held(&swhash->hlist_mutex));
6712 static void swevent_hlist_release(struct swevent_htable *swhash)
6714 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6719 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6720 kfree_rcu(hlist, rcu_head);
6723 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6725 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6727 mutex_lock(&swhash->hlist_mutex);
6729 if (!--swhash->hlist_refcount)
6730 swevent_hlist_release(swhash);
6732 mutex_unlock(&swhash->hlist_mutex);
6735 static void swevent_hlist_put(struct perf_event *event)
6739 for_each_possible_cpu(cpu)
6740 swevent_hlist_put_cpu(event, cpu);
6743 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6745 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6748 mutex_lock(&swhash->hlist_mutex);
6749 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6750 struct swevent_hlist *hlist;
6752 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6757 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6759 swhash->hlist_refcount++;
6761 mutex_unlock(&swhash->hlist_mutex);
6766 static int swevent_hlist_get(struct perf_event *event)
6769 int cpu, failed_cpu;
6772 for_each_possible_cpu(cpu) {
6773 err = swevent_hlist_get_cpu(event, cpu);
6783 for_each_possible_cpu(cpu) {
6784 if (cpu == failed_cpu)
6786 swevent_hlist_put_cpu(event, cpu);
6793 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6795 static void sw_perf_event_destroy(struct perf_event *event)
6797 u64 event_id = event->attr.config;
6799 WARN_ON(event->parent);
6801 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6802 swevent_hlist_put(event);
6805 static int perf_swevent_init(struct perf_event *event)
6807 u64 event_id = event->attr.config;
6809 if (event->attr.type != PERF_TYPE_SOFTWARE)
6813 * no branch sampling for software events
6815 if (has_branch_stack(event))
6819 case PERF_COUNT_SW_CPU_CLOCK:
6820 case PERF_COUNT_SW_TASK_CLOCK:
6827 if (event_id >= PERF_COUNT_SW_MAX)
6830 if (!event->parent) {
6833 err = swevent_hlist_get(event);
6837 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6838 event->destroy = sw_perf_event_destroy;
6844 static struct pmu perf_swevent = {
6845 .task_ctx_nr = perf_sw_context,
6847 .capabilities = PERF_PMU_CAP_NO_NMI,
6849 .event_init = perf_swevent_init,
6850 .add = perf_swevent_add,
6851 .del = perf_swevent_del,
6852 .start = perf_swevent_start,
6853 .stop = perf_swevent_stop,
6854 .read = perf_swevent_read,
6857 #ifdef CONFIG_EVENT_TRACING
6859 static int perf_tp_filter_match(struct perf_event *event,
6860 struct perf_sample_data *data)
6862 void *record = data->raw->data;
6864 /* only top level events have filters set */
6866 event = event->parent;
6868 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6873 static int perf_tp_event_match(struct perf_event *event,
6874 struct perf_sample_data *data,
6875 struct pt_regs *regs)
6877 if (event->hw.state & PERF_HES_STOPPED)
6880 * All tracepoints are from kernel-space.
6882 if (event->attr.exclude_kernel)
6885 if (!perf_tp_filter_match(event, data))
6891 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6892 struct pt_regs *regs, struct hlist_head *head, int rctx,
6893 struct task_struct *task)
6895 struct perf_sample_data data;
6896 struct perf_event *event;
6898 struct perf_raw_record raw = {
6903 perf_sample_data_init(&data, addr, 0);
6906 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6907 if (perf_tp_event_match(event, &data, regs))
6908 perf_swevent_event(event, count, &data, regs);
6912 * If we got specified a target task, also iterate its context and
6913 * deliver this event there too.
6915 if (task && task != current) {
6916 struct perf_event_context *ctx;
6917 struct trace_entry *entry = record;
6920 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6924 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6925 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6927 if (event->attr.config != entry->type)
6929 if (perf_tp_event_match(event, &data, regs))
6930 perf_swevent_event(event, count, &data, regs);
6936 perf_swevent_put_recursion_context(rctx);
6938 EXPORT_SYMBOL_GPL(perf_tp_event);
6940 static void tp_perf_event_destroy(struct perf_event *event)
6942 perf_trace_destroy(event);
6945 static int perf_tp_event_init(struct perf_event *event)
6949 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6953 * no branch sampling for tracepoint events
6955 if (has_branch_stack(event))
6958 err = perf_trace_init(event);
6962 event->destroy = tp_perf_event_destroy;
6967 static struct pmu perf_tracepoint = {
6968 .task_ctx_nr = perf_sw_context,
6970 .event_init = perf_tp_event_init,
6971 .add = perf_trace_add,
6972 .del = perf_trace_del,
6973 .start = perf_swevent_start,
6974 .stop = perf_swevent_stop,
6975 .read = perf_swevent_read,
6978 static inline void perf_tp_register(void)
6980 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6983 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6988 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6991 filter_str = strndup_user(arg, PAGE_SIZE);
6992 if (IS_ERR(filter_str))
6993 return PTR_ERR(filter_str);
6995 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7001 static void perf_event_free_filter(struct perf_event *event)
7003 ftrace_profile_free_filter(event);
7006 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7008 struct bpf_prog *prog;
7010 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7013 if (event->tp_event->prog)
7016 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7017 /* bpf programs can only be attached to u/kprobes */
7020 prog = bpf_prog_get(prog_fd);
7022 return PTR_ERR(prog);
7024 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7025 /* valid fd, but invalid bpf program type */
7030 event->tp_event->prog = prog;
7035 static void perf_event_free_bpf_prog(struct perf_event *event)
7037 struct bpf_prog *prog;
7039 if (!event->tp_event)
7042 prog = event->tp_event->prog;
7044 event->tp_event->prog = NULL;
7051 static inline void perf_tp_register(void)
7055 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7060 static void perf_event_free_filter(struct perf_event *event)
7064 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7069 static void perf_event_free_bpf_prog(struct perf_event *event)
7072 #endif /* CONFIG_EVENT_TRACING */
7074 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7075 void perf_bp_event(struct perf_event *bp, void *data)
7077 struct perf_sample_data sample;
7078 struct pt_regs *regs = data;
7080 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7082 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7083 perf_swevent_event(bp, 1, &sample, regs);
7088 * hrtimer based swevent callback
7091 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7093 enum hrtimer_restart ret = HRTIMER_RESTART;
7094 struct perf_sample_data data;
7095 struct pt_regs *regs;
7096 struct perf_event *event;
7099 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7101 if (event->state != PERF_EVENT_STATE_ACTIVE)
7102 return HRTIMER_NORESTART;
7104 event->pmu->read(event);
7106 perf_sample_data_init(&data, 0, event->hw.last_period);
7107 regs = get_irq_regs();
7109 if (regs && !perf_exclude_event(event, regs)) {
7110 if (!(event->attr.exclude_idle && is_idle_task(current)))
7111 if (__perf_event_overflow(event, 1, &data, regs))
7112 ret = HRTIMER_NORESTART;
7115 period = max_t(u64, 10000, event->hw.sample_period);
7116 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7121 static void perf_swevent_start_hrtimer(struct perf_event *event)
7123 struct hw_perf_event *hwc = &event->hw;
7126 if (!is_sampling_event(event))
7129 period = local64_read(&hwc->period_left);
7134 local64_set(&hwc->period_left, 0);
7136 period = max_t(u64, 10000, hwc->sample_period);
7138 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7139 HRTIMER_MODE_REL_PINNED);
7142 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7144 struct hw_perf_event *hwc = &event->hw;
7146 if (is_sampling_event(event)) {
7147 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7148 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7150 hrtimer_cancel(&hwc->hrtimer);
7154 static void perf_swevent_init_hrtimer(struct perf_event *event)
7156 struct hw_perf_event *hwc = &event->hw;
7158 if (!is_sampling_event(event))
7161 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7162 hwc->hrtimer.function = perf_swevent_hrtimer;
7165 * Since hrtimers have a fixed rate, we can do a static freq->period
7166 * mapping and avoid the whole period adjust feedback stuff.
7168 if (event->attr.freq) {
7169 long freq = event->attr.sample_freq;
7171 event->attr.sample_period = NSEC_PER_SEC / freq;
7172 hwc->sample_period = event->attr.sample_period;
7173 local64_set(&hwc->period_left, hwc->sample_period);
7174 hwc->last_period = hwc->sample_period;
7175 event->attr.freq = 0;
7180 * Software event: cpu wall time clock
7183 static void cpu_clock_event_update(struct perf_event *event)
7188 now = local_clock();
7189 prev = local64_xchg(&event->hw.prev_count, now);
7190 local64_add(now - prev, &event->count);
7193 static void cpu_clock_event_start(struct perf_event *event, int flags)
7195 local64_set(&event->hw.prev_count, local_clock());
7196 perf_swevent_start_hrtimer(event);
7199 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7201 perf_swevent_cancel_hrtimer(event);
7202 cpu_clock_event_update(event);
7205 static int cpu_clock_event_add(struct perf_event *event, int flags)
7207 if (flags & PERF_EF_START)
7208 cpu_clock_event_start(event, flags);
7209 perf_event_update_userpage(event);
7214 static void cpu_clock_event_del(struct perf_event *event, int flags)
7216 cpu_clock_event_stop(event, flags);
7219 static void cpu_clock_event_read(struct perf_event *event)
7221 cpu_clock_event_update(event);
7224 static int cpu_clock_event_init(struct perf_event *event)
7226 if (event->attr.type != PERF_TYPE_SOFTWARE)
7229 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7233 * no branch sampling for software events
7235 if (has_branch_stack(event))
7238 perf_swevent_init_hrtimer(event);
7243 static struct pmu perf_cpu_clock = {
7244 .task_ctx_nr = perf_sw_context,
7246 .capabilities = PERF_PMU_CAP_NO_NMI,
7248 .event_init = cpu_clock_event_init,
7249 .add = cpu_clock_event_add,
7250 .del = cpu_clock_event_del,
7251 .start = cpu_clock_event_start,
7252 .stop = cpu_clock_event_stop,
7253 .read = cpu_clock_event_read,
7257 * Software event: task time clock
7260 static void task_clock_event_update(struct perf_event *event, u64 now)
7265 prev = local64_xchg(&event->hw.prev_count, now);
7267 local64_add(delta, &event->count);
7270 static void task_clock_event_start(struct perf_event *event, int flags)
7272 local64_set(&event->hw.prev_count, event->ctx->time);
7273 perf_swevent_start_hrtimer(event);
7276 static void task_clock_event_stop(struct perf_event *event, int flags)
7278 perf_swevent_cancel_hrtimer(event);
7279 task_clock_event_update(event, event->ctx->time);
7282 static int task_clock_event_add(struct perf_event *event, int flags)
7284 if (flags & PERF_EF_START)
7285 task_clock_event_start(event, flags);
7286 perf_event_update_userpage(event);
7291 static void task_clock_event_del(struct perf_event *event, int flags)
7293 task_clock_event_stop(event, PERF_EF_UPDATE);
7296 static void task_clock_event_read(struct perf_event *event)
7298 u64 now = perf_clock();
7299 u64 delta = now - event->ctx->timestamp;
7300 u64 time = event->ctx->time + delta;
7302 task_clock_event_update(event, time);
7305 static int task_clock_event_init(struct perf_event *event)
7307 if (event->attr.type != PERF_TYPE_SOFTWARE)
7310 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7314 * no branch sampling for software events
7316 if (has_branch_stack(event))
7319 perf_swevent_init_hrtimer(event);
7324 static struct pmu perf_task_clock = {
7325 .task_ctx_nr = perf_sw_context,
7327 .capabilities = PERF_PMU_CAP_NO_NMI,
7329 .event_init = task_clock_event_init,
7330 .add = task_clock_event_add,
7331 .del = task_clock_event_del,
7332 .start = task_clock_event_start,
7333 .stop = task_clock_event_stop,
7334 .read = task_clock_event_read,
7337 static void perf_pmu_nop_void(struct pmu *pmu)
7341 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7345 static int perf_pmu_nop_int(struct pmu *pmu)
7350 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7352 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7354 __this_cpu_write(nop_txn_flags, flags);
7356 if (flags & ~PERF_PMU_TXN_ADD)
7359 perf_pmu_disable(pmu);
7362 static int perf_pmu_commit_txn(struct pmu *pmu)
7364 unsigned int flags = __this_cpu_read(nop_txn_flags);
7366 __this_cpu_write(nop_txn_flags, 0);
7368 if (flags & ~PERF_PMU_TXN_ADD)
7371 perf_pmu_enable(pmu);
7375 static void perf_pmu_cancel_txn(struct pmu *pmu)
7377 unsigned int flags = __this_cpu_read(nop_txn_flags);
7379 __this_cpu_write(nop_txn_flags, 0);
7381 if (flags & ~PERF_PMU_TXN_ADD)
7384 perf_pmu_enable(pmu);
7387 static int perf_event_idx_default(struct perf_event *event)
7393 * Ensures all contexts with the same task_ctx_nr have the same
7394 * pmu_cpu_context too.
7396 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7403 list_for_each_entry(pmu, &pmus, entry) {
7404 if (pmu->task_ctx_nr == ctxn)
7405 return pmu->pmu_cpu_context;
7411 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7415 for_each_possible_cpu(cpu) {
7416 struct perf_cpu_context *cpuctx;
7418 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7420 if (cpuctx->unique_pmu == old_pmu)
7421 cpuctx->unique_pmu = pmu;
7425 static void free_pmu_context(struct pmu *pmu)
7429 mutex_lock(&pmus_lock);
7431 * Like a real lame refcount.
7433 list_for_each_entry(i, &pmus, entry) {
7434 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7435 update_pmu_context(i, pmu);
7440 free_percpu(pmu->pmu_cpu_context);
7442 mutex_unlock(&pmus_lock);
7444 static struct idr pmu_idr;
7447 type_show(struct device *dev, struct device_attribute *attr, char *page)
7449 struct pmu *pmu = dev_get_drvdata(dev);
7451 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7453 static DEVICE_ATTR_RO(type);
7456 perf_event_mux_interval_ms_show(struct device *dev,
7457 struct device_attribute *attr,
7460 struct pmu *pmu = dev_get_drvdata(dev);
7462 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7465 static DEFINE_MUTEX(mux_interval_mutex);
7468 perf_event_mux_interval_ms_store(struct device *dev,
7469 struct device_attribute *attr,
7470 const char *buf, size_t count)
7472 struct pmu *pmu = dev_get_drvdata(dev);
7473 int timer, cpu, ret;
7475 ret = kstrtoint(buf, 0, &timer);
7482 /* same value, noting to do */
7483 if (timer == pmu->hrtimer_interval_ms)
7486 mutex_lock(&mux_interval_mutex);
7487 pmu->hrtimer_interval_ms = timer;
7489 /* update all cpuctx for this PMU */
7491 for_each_online_cpu(cpu) {
7492 struct perf_cpu_context *cpuctx;
7493 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7494 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7496 cpu_function_call(cpu,
7497 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7500 mutex_unlock(&mux_interval_mutex);
7504 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7506 static struct attribute *pmu_dev_attrs[] = {
7507 &dev_attr_type.attr,
7508 &dev_attr_perf_event_mux_interval_ms.attr,
7511 ATTRIBUTE_GROUPS(pmu_dev);
7513 static int pmu_bus_running;
7514 static struct bus_type pmu_bus = {
7515 .name = "event_source",
7516 .dev_groups = pmu_dev_groups,
7519 static void pmu_dev_release(struct device *dev)
7524 static int pmu_dev_alloc(struct pmu *pmu)
7528 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7532 pmu->dev->groups = pmu->attr_groups;
7533 device_initialize(pmu->dev);
7534 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7538 dev_set_drvdata(pmu->dev, pmu);
7539 pmu->dev->bus = &pmu_bus;
7540 pmu->dev->release = pmu_dev_release;
7541 ret = device_add(pmu->dev);
7549 put_device(pmu->dev);
7553 static struct lock_class_key cpuctx_mutex;
7554 static struct lock_class_key cpuctx_lock;
7556 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7560 mutex_lock(&pmus_lock);
7562 pmu->pmu_disable_count = alloc_percpu(int);
7563 if (!pmu->pmu_disable_count)
7572 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7580 if (pmu_bus_running) {
7581 ret = pmu_dev_alloc(pmu);
7587 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7588 if (pmu->pmu_cpu_context)
7589 goto got_cpu_context;
7592 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7593 if (!pmu->pmu_cpu_context)
7596 for_each_possible_cpu(cpu) {
7597 struct perf_cpu_context *cpuctx;
7599 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7600 __perf_event_init_context(&cpuctx->ctx);
7601 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7602 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7603 cpuctx->ctx.pmu = pmu;
7605 __perf_mux_hrtimer_init(cpuctx, cpu);
7607 cpuctx->unique_pmu = pmu;
7611 if (!pmu->start_txn) {
7612 if (pmu->pmu_enable) {
7614 * If we have pmu_enable/pmu_disable calls, install
7615 * transaction stubs that use that to try and batch
7616 * hardware accesses.
7618 pmu->start_txn = perf_pmu_start_txn;
7619 pmu->commit_txn = perf_pmu_commit_txn;
7620 pmu->cancel_txn = perf_pmu_cancel_txn;
7622 pmu->start_txn = perf_pmu_nop_txn;
7623 pmu->commit_txn = perf_pmu_nop_int;
7624 pmu->cancel_txn = perf_pmu_nop_void;
7628 if (!pmu->pmu_enable) {
7629 pmu->pmu_enable = perf_pmu_nop_void;
7630 pmu->pmu_disable = perf_pmu_nop_void;
7633 if (!pmu->event_idx)
7634 pmu->event_idx = perf_event_idx_default;
7636 list_add_rcu(&pmu->entry, &pmus);
7637 atomic_set(&pmu->exclusive_cnt, 0);
7640 mutex_unlock(&pmus_lock);
7645 device_del(pmu->dev);
7646 put_device(pmu->dev);
7649 if (pmu->type >= PERF_TYPE_MAX)
7650 idr_remove(&pmu_idr, pmu->type);
7653 free_percpu(pmu->pmu_disable_count);
7656 EXPORT_SYMBOL_GPL(perf_pmu_register);
7658 void perf_pmu_unregister(struct pmu *pmu)
7660 mutex_lock(&pmus_lock);
7661 list_del_rcu(&pmu->entry);
7662 mutex_unlock(&pmus_lock);
7665 * We dereference the pmu list under both SRCU and regular RCU, so
7666 * synchronize against both of those.
7668 synchronize_srcu(&pmus_srcu);
7671 free_percpu(pmu->pmu_disable_count);
7672 if (pmu->type >= PERF_TYPE_MAX)
7673 idr_remove(&pmu_idr, pmu->type);
7674 device_del(pmu->dev);
7675 put_device(pmu->dev);
7676 free_pmu_context(pmu);
7678 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7680 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7682 struct perf_event_context *ctx = NULL;
7685 if (!try_module_get(pmu->module))
7688 if (event->group_leader != event) {
7690 * This ctx->mutex can nest when we're called through
7691 * inheritance. See the perf_event_ctx_lock_nested() comment.
7693 ctx = perf_event_ctx_lock_nested(event->group_leader,
7694 SINGLE_DEPTH_NESTING);
7699 ret = pmu->event_init(event);
7702 perf_event_ctx_unlock(event->group_leader, ctx);
7705 module_put(pmu->module);
7710 static struct pmu *perf_init_event(struct perf_event *event)
7712 struct pmu *pmu = NULL;
7716 idx = srcu_read_lock(&pmus_srcu);
7719 pmu = idr_find(&pmu_idr, event->attr.type);
7722 ret = perf_try_init_event(pmu, event);
7728 list_for_each_entry_rcu(pmu, &pmus, entry) {
7729 ret = perf_try_init_event(pmu, event);
7733 if (ret != -ENOENT) {
7738 pmu = ERR_PTR(-ENOENT);
7740 srcu_read_unlock(&pmus_srcu, idx);
7745 static void account_event_cpu(struct perf_event *event, int cpu)
7750 if (is_cgroup_event(event))
7751 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7754 static void account_event(struct perf_event *event)
7761 if (event->attach_state & PERF_ATTACH_TASK)
7763 if (event->attr.mmap || event->attr.mmap_data)
7764 atomic_inc(&nr_mmap_events);
7765 if (event->attr.comm)
7766 atomic_inc(&nr_comm_events);
7767 if (event->attr.task)
7768 atomic_inc(&nr_task_events);
7769 if (event->attr.freq) {
7770 if (atomic_inc_return(&nr_freq_events) == 1)
7771 tick_nohz_full_kick_all();
7773 if (event->attr.context_switch) {
7774 atomic_inc(&nr_switch_events);
7777 if (has_branch_stack(event))
7779 if (is_cgroup_event(event))
7783 static_key_slow_inc(&perf_sched_events.key);
7785 account_event_cpu(event, event->cpu);
7789 * Allocate and initialize a event structure
7791 static struct perf_event *
7792 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7793 struct task_struct *task,
7794 struct perf_event *group_leader,
7795 struct perf_event *parent_event,
7796 perf_overflow_handler_t overflow_handler,
7797 void *context, int cgroup_fd)
7800 struct perf_event *event;
7801 struct hw_perf_event *hwc;
7804 if ((unsigned)cpu >= nr_cpu_ids) {
7805 if (!task || cpu != -1)
7806 return ERR_PTR(-EINVAL);
7809 event = kzalloc(sizeof(*event), GFP_KERNEL);
7811 return ERR_PTR(-ENOMEM);
7814 * Single events are their own group leaders, with an
7815 * empty sibling list:
7818 group_leader = event;
7820 mutex_init(&event->child_mutex);
7821 INIT_LIST_HEAD(&event->child_list);
7823 INIT_LIST_HEAD(&event->group_entry);
7824 INIT_LIST_HEAD(&event->event_entry);
7825 INIT_LIST_HEAD(&event->sibling_list);
7826 INIT_LIST_HEAD(&event->rb_entry);
7827 INIT_LIST_HEAD(&event->active_entry);
7828 INIT_HLIST_NODE(&event->hlist_entry);
7831 init_waitqueue_head(&event->waitq);
7832 init_irq_work(&event->pending, perf_pending_event);
7834 mutex_init(&event->mmap_mutex);
7836 atomic_long_set(&event->refcount, 1);
7838 event->attr = *attr;
7839 event->group_leader = group_leader;
7843 event->parent = parent_event;
7845 event->ns = get_pid_ns(task_active_pid_ns(current));
7846 event->id = atomic64_inc_return(&perf_event_id);
7848 event->state = PERF_EVENT_STATE_INACTIVE;
7851 event->attach_state = PERF_ATTACH_TASK;
7853 * XXX pmu::event_init needs to know what task to account to
7854 * and we cannot use the ctx information because we need the
7855 * pmu before we get a ctx.
7857 event->hw.target = task;
7860 event->clock = &local_clock;
7862 event->clock = parent_event->clock;
7864 if (!overflow_handler && parent_event) {
7865 overflow_handler = parent_event->overflow_handler;
7866 context = parent_event->overflow_handler_context;
7869 event->overflow_handler = overflow_handler;
7870 event->overflow_handler_context = context;
7872 perf_event__state_init(event);
7877 hwc->sample_period = attr->sample_period;
7878 if (attr->freq && attr->sample_freq)
7879 hwc->sample_period = 1;
7880 hwc->last_period = hwc->sample_period;
7882 local64_set(&hwc->period_left, hwc->sample_period);
7885 * we currently do not support PERF_FORMAT_GROUP on inherited events
7887 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7890 if (!has_branch_stack(event))
7891 event->attr.branch_sample_type = 0;
7893 if (cgroup_fd != -1) {
7894 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7899 pmu = perf_init_event(event);
7902 else if (IS_ERR(pmu)) {
7907 err = exclusive_event_init(event);
7911 if (!event->parent) {
7912 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7913 err = get_callchain_buffers();
7922 exclusive_event_destroy(event);
7926 event->destroy(event);
7927 module_put(pmu->module);
7929 if (is_cgroup_event(event))
7930 perf_detach_cgroup(event);
7932 put_pid_ns(event->ns);
7935 return ERR_PTR(err);
7938 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7939 struct perf_event_attr *attr)
7944 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7948 * zero the full structure, so that a short copy will be nice.
7950 memset(attr, 0, sizeof(*attr));
7952 ret = get_user(size, &uattr->size);
7956 if (size > PAGE_SIZE) /* silly large */
7959 if (!size) /* abi compat */
7960 size = PERF_ATTR_SIZE_VER0;
7962 if (size < PERF_ATTR_SIZE_VER0)
7966 * If we're handed a bigger struct than we know of,
7967 * ensure all the unknown bits are 0 - i.e. new
7968 * user-space does not rely on any kernel feature
7969 * extensions we dont know about yet.
7971 if (size > sizeof(*attr)) {
7972 unsigned char __user *addr;
7973 unsigned char __user *end;
7976 addr = (void __user *)uattr + sizeof(*attr);
7977 end = (void __user *)uattr + size;
7979 for (; addr < end; addr++) {
7980 ret = get_user(val, addr);
7986 size = sizeof(*attr);
7989 ret = copy_from_user(attr, uattr, size);
7993 if (attr->__reserved_1)
7996 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
7999 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8002 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8003 u64 mask = attr->branch_sample_type;
8005 /* only using defined bits */
8006 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8009 /* at least one branch bit must be set */
8010 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8013 /* propagate priv level, when not set for branch */
8014 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8016 /* exclude_kernel checked on syscall entry */
8017 if (!attr->exclude_kernel)
8018 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8020 if (!attr->exclude_user)
8021 mask |= PERF_SAMPLE_BRANCH_USER;
8023 if (!attr->exclude_hv)
8024 mask |= PERF_SAMPLE_BRANCH_HV;
8026 * adjust user setting (for HW filter setup)
8028 attr->branch_sample_type = mask;
8030 /* privileged levels capture (kernel, hv): check permissions */
8031 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8032 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8036 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8037 ret = perf_reg_validate(attr->sample_regs_user);
8042 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8043 if (!arch_perf_have_user_stack_dump())
8047 * We have __u32 type for the size, but so far
8048 * we can only use __u16 as maximum due to the
8049 * __u16 sample size limit.
8051 if (attr->sample_stack_user >= USHRT_MAX)
8053 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8057 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8058 ret = perf_reg_validate(attr->sample_regs_intr);
8063 put_user(sizeof(*attr), &uattr->size);
8069 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8071 struct ring_buffer *rb = NULL;
8077 /* don't allow circular references */
8078 if (event == output_event)
8082 * Don't allow cross-cpu buffers
8084 if (output_event->cpu != event->cpu)
8088 * If its not a per-cpu rb, it must be the same task.
8090 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8094 * Mixing clocks in the same buffer is trouble you don't need.
8096 if (output_event->clock != event->clock)
8100 * If both events generate aux data, they must be on the same PMU
8102 if (has_aux(event) && has_aux(output_event) &&
8103 event->pmu != output_event->pmu)
8107 mutex_lock(&event->mmap_mutex);
8108 /* Can't redirect output if we've got an active mmap() */
8109 if (atomic_read(&event->mmap_count))
8113 /* get the rb we want to redirect to */
8114 rb = ring_buffer_get(output_event);
8119 ring_buffer_attach(event, rb);
8123 mutex_unlock(&event->mmap_mutex);
8129 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8135 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8138 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8140 bool nmi_safe = false;
8143 case CLOCK_MONOTONIC:
8144 event->clock = &ktime_get_mono_fast_ns;
8148 case CLOCK_MONOTONIC_RAW:
8149 event->clock = &ktime_get_raw_fast_ns;
8153 case CLOCK_REALTIME:
8154 event->clock = &ktime_get_real_ns;
8157 case CLOCK_BOOTTIME:
8158 event->clock = &ktime_get_boot_ns;
8162 event->clock = &ktime_get_tai_ns;
8169 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8176 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8178 * @attr_uptr: event_id type attributes for monitoring/sampling
8181 * @group_fd: group leader event fd
8183 SYSCALL_DEFINE5(perf_event_open,
8184 struct perf_event_attr __user *, attr_uptr,
8185 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8187 struct perf_event *group_leader = NULL, *output_event = NULL;
8188 struct perf_event *event, *sibling;
8189 struct perf_event_attr attr;
8190 struct perf_event_context *ctx, *uninitialized_var(gctx);
8191 struct file *event_file = NULL;
8192 struct fd group = {NULL, 0};
8193 struct task_struct *task = NULL;
8198 int f_flags = O_RDWR;
8201 /* for future expandability... */
8202 if (flags & ~PERF_FLAG_ALL)
8205 err = perf_copy_attr(attr_uptr, &attr);
8209 if (!attr.exclude_kernel) {
8210 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8215 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8218 if (attr.sample_period & (1ULL << 63))
8223 * In cgroup mode, the pid argument is used to pass the fd
8224 * opened to the cgroup directory in cgroupfs. The cpu argument
8225 * designates the cpu on which to monitor threads from that
8228 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8231 if (flags & PERF_FLAG_FD_CLOEXEC)
8232 f_flags |= O_CLOEXEC;
8234 event_fd = get_unused_fd_flags(f_flags);
8238 if (group_fd != -1) {
8239 err = perf_fget_light(group_fd, &group);
8242 group_leader = group.file->private_data;
8243 if (flags & PERF_FLAG_FD_OUTPUT)
8244 output_event = group_leader;
8245 if (flags & PERF_FLAG_FD_NO_GROUP)
8246 group_leader = NULL;
8249 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8250 task = find_lively_task_by_vpid(pid);
8252 err = PTR_ERR(task);
8257 if (task && group_leader &&
8258 group_leader->attr.inherit != attr.inherit) {
8265 if (flags & PERF_FLAG_PID_CGROUP)
8268 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8269 NULL, NULL, cgroup_fd);
8270 if (IS_ERR(event)) {
8271 err = PTR_ERR(event);
8275 if (is_sampling_event(event)) {
8276 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8282 account_event(event);
8285 * Special case software events and allow them to be part of
8286 * any hardware group.
8290 if (attr.use_clockid) {
8291 err = perf_event_set_clock(event, attr.clockid);
8297 (is_software_event(event) != is_software_event(group_leader))) {
8298 if (is_software_event(event)) {
8300 * If event and group_leader are not both a software
8301 * event, and event is, then group leader is not.
8303 * Allow the addition of software events to !software
8304 * groups, this is safe because software events never
8307 pmu = group_leader->pmu;
8308 } else if (is_software_event(group_leader) &&
8309 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8311 * In case the group is a pure software group, and we
8312 * try to add a hardware event, move the whole group to
8313 * the hardware context.
8320 * Get the target context (task or percpu):
8322 ctx = find_get_context(pmu, task, event);
8328 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8334 put_task_struct(task);
8339 * Look up the group leader (we will attach this event to it):
8345 * Do not allow a recursive hierarchy (this new sibling
8346 * becoming part of another group-sibling):
8348 if (group_leader->group_leader != group_leader)
8351 /* All events in a group should have the same clock */
8352 if (group_leader->clock != event->clock)
8356 * Do not allow to attach to a group in a different
8357 * task or CPU context:
8361 * Make sure we're both on the same task, or both
8364 if (group_leader->ctx->task != ctx->task)
8368 * Make sure we're both events for the same CPU;
8369 * grouping events for different CPUs is broken; since
8370 * you can never concurrently schedule them anyhow.
8372 if (group_leader->cpu != event->cpu)
8375 if (group_leader->ctx != ctx)
8380 * Only a group leader can be exclusive or pinned
8382 if (attr.exclusive || attr.pinned)
8387 err = perf_event_set_output(event, output_event);
8392 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8394 if (IS_ERR(event_file)) {
8395 err = PTR_ERR(event_file);
8400 gctx = group_leader->ctx;
8401 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8403 mutex_lock(&ctx->mutex);
8406 if (!perf_event_validate_size(event)) {
8412 * Must be under the same ctx::mutex as perf_install_in_context(),
8413 * because we need to serialize with concurrent event creation.
8415 if (!exclusive_event_installable(event, ctx)) {
8416 /* exclusive and group stuff are assumed mutually exclusive */
8417 WARN_ON_ONCE(move_group);
8423 WARN_ON_ONCE(ctx->parent_ctx);
8427 * See perf_event_ctx_lock() for comments on the details
8428 * of swizzling perf_event::ctx.
8430 perf_remove_from_context(group_leader, false);
8432 list_for_each_entry(sibling, &group_leader->sibling_list,
8434 perf_remove_from_context(sibling, false);
8439 * Wait for everybody to stop referencing the events through
8440 * the old lists, before installing it on new lists.
8445 * Install the group siblings before the group leader.
8447 * Because a group leader will try and install the entire group
8448 * (through the sibling list, which is still in-tact), we can
8449 * end up with siblings installed in the wrong context.
8451 * By installing siblings first we NO-OP because they're not
8452 * reachable through the group lists.
8454 list_for_each_entry(sibling, &group_leader->sibling_list,
8456 perf_event__state_init(sibling);
8457 perf_install_in_context(ctx, sibling, sibling->cpu);
8462 * Removing from the context ends up with disabled
8463 * event. What we want here is event in the initial
8464 * startup state, ready to be add into new context.
8466 perf_event__state_init(group_leader);
8467 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8471 * Now that all events are installed in @ctx, nothing
8472 * references @gctx anymore, so drop the last reference we have
8479 * Precalculate sample_data sizes; do while holding ctx::mutex such
8480 * that we're serialized against further additions and before
8481 * perf_install_in_context() which is the point the event is active and
8482 * can use these values.
8484 perf_event__header_size(event);
8485 perf_event__id_header_size(event);
8487 event->owner = current;
8489 perf_install_in_context(ctx, event, event->cpu);
8490 perf_unpin_context(ctx);
8493 mutex_unlock(&gctx->mutex);
8494 mutex_unlock(&ctx->mutex);
8498 mutex_lock(¤t->perf_event_mutex);
8499 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8500 mutex_unlock(¤t->perf_event_mutex);
8503 * Drop the reference on the group_event after placing the
8504 * new event on the sibling_list. This ensures destruction
8505 * of the group leader will find the pointer to itself in
8506 * perf_group_detach().
8509 fd_install(event_fd, event_file);
8514 mutex_unlock(&gctx->mutex);
8515 mutex_unlock(&ctx->mutex);
8519 perf_unpin_context(ctx);
8527 put_task_struct(task);
8531 put_unused_fd(event_fd);
8536 * perf_event_create_kernel_counter
8538 * @attr: attributes of the counter to create
8539 * @cpu: cpu in which the counter is bound
8540 * @task: task to profile (NULL for percpu)
8543 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8544 struct task_struct *task,
8545 perf_overflow_handler_t overflow_handler,
8548 struct perf_event_context *ctx;
8549 struct perf_event *event;
8553 * Get the target context (task or percpu):
8556 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8557 overflow_handler, context, -1);
8558 if (IS_ERR(event)) {
8559 err = PTR_ERR(event);
8563 /* Mark owner so we could distinguish it from user events. */
8564 event->owner = TASK_TOMBSTONE;
8566 account_event(event);
8568 ctx = find_get_context(event->pmu, task, event);
8574 WARN_ON_ONCE(ctx->parent_ctx);
8575 mutex_lock(&ctx->mutex);
8576 if (!exclusive_event_installable(event, ctx)) {
8577 mutex_unlock(&ctx->mutex);
8578 perf_unpin_context(ctx);
8584 perf_install_in_context(ctx, event, cpu);
8585 perf_unpin_context(ctx);
8586 mutex_unlock(&ctx->mutex);
8593 return ERR_PTR(err);
8595 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8597 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8599 struct perf_event_context *src_ctx;
8600 struct perf_event_context *dst_ctx;
8601 struct perf_event *event, *tmp;
8604 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8605 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8608 * See perf_event_ctx_lock() for comments on the details
8609 * of swizzling perf_event::ctx.
8611 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8612 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8614 perf_remove_from_context(event, false);
8615 unaccount_event_cpu(event, src_cpu);
8617 list_add(&event->migrate_entry, &events);
8621 * Wait for the events to quiesce before re-instating them.
8626 * Re-instate events in 2 passes.
8628 * Skip over group leaders and only install siblings on this first
8629 * pass, siblings will not get enabled without a leader, however a
8630 * leader will enable its siblings, even if those are still on the old
8633 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8634 if (event->group_leader == event)
8637 list_del(&event->migrate_entry);
8638 if (event->state >= PERF_EVENT_STATE_OFF)
8639 event->state = PERF_EVENT_STATE_INACTIVE;
8640 account_event_cpu(event, dst_cpu);
8641 perf_install_in_context(dst_ctx, event, dst_cpu);
8646 * Once all the siblings are setup properly, install the group leaders
8649 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8650 list_del(&event->migrate_entry);
8651 if (event->state >= PERF_EVENT_STATE_OFF)
8652 event->state = PERF_EVENT_STATE_INACTIVE;
8653 account_event_cpu(event, dst_cpu);
8654 perf_install_in_context(dst_ctx, event, dst_cpu);
8657 mutex_unlock(&dst_ctx->mutex);
8658 mutex_unlock(&src_ctx->mutex);
8660 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8662 static void sync_child_event(struct perf_event *child_event,
8663 struct task_struct *child)
8665 struct perf_event *parent_event = child_event->parent;
8668 if (child_event->attr.inherit_stat)
8669 perf_event_read_event(child_event, child);
8671 child_val = perf_event_count(child_event);
8674 * Add back the child's count to the parent's count:
8676 atomic64_add(child_val, &parent_event->child_count);
8677 atomic64_add(child_event->total_time_enabled,
8678 &parent_event->child_total_time_enabled);
8679 atomic64_add(child_event->total_time_running,
8680 &parent_event->child_total_time_running);
8683 * Remove this event from the parent's list
8685 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8686 mutex_lock(&parent_event->child_mutex);
8687 list_del_init(&child_event->child_list);
8688 mutex_unlock(&parent_event->child_mutex);
8691 * Make sure user/parent get notified, that we just
8694 perf_event_wakeup(parent_event);
8697 * Release the parent event, if this was the last
8700 put_event(parent_event);
8704 __perf_event_exit_task(struct perf_event *child_event,
8705 struct perf_event_context *child_ctx,
8706 struct task_struct *child)
8709 * Do not destroy the 'original' grouping; because of the context
8710 * switch optimization the original events could've ended up in a
8711 * random child task.
8713 * If we were to destroy the original group, all group related
8714 * operations would cease to function properly after this random
8717 * Do destroy all inherited groups, we don't care about those
8718 * and being thorough is better.
8720 raw_spin_lock_irq(&child_ctx->lock);
8721 WARN_ON_ONCE(child_ctx->is_active);
8723 if (!!child_event->parent)
8724 perf_group_detach(child_event);
8725 list_del_event(child_event, child_ctx);
8726 raw_spin_unlock_irq(&child_ctx->lock);
8729 * It can happen that the parent exits first, and has events
8730 * that are still around due to the child reference. These
8731 * events need to be zapped.
8733 if (child_event->parent) {
8734 sync_child_event(child_event, child);
8735 free_event(child_event);
8737 child_event->state = PERF_EVENT_STATE_EXIT;
8738 perf_event_wakeup(child_event);
8742 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8744 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8745 struct perf_event *child_event, *next;
8747 WARN_ON_ONCE(child != current);
8749 child_ctx = perf_pin_task_context(child, ctxn);
8754 * In order to reduce the amount of tricky in ctx tear-down, we hold
8755 * ctx::mutex over the entire thing. This serializes against almost
8756 * everything that wants to access the ctx.
8758 * The exception is sys_perf_event_open() /
8759 * perf_event_create_kernel_count() which does find_get_context()
8760 * without ctx::mutex (it cannot because of the move_group double mutex
8761 * lock thing). See the comments in perf_install_in_context().
8763 * We can recurse on the same lock type through:
8765 * __perf_event_exit_task()
8766 * sync_child_event()
8768 * mutex_lock(&ctx->mutex)
8770 * But since its the parent context it won't be the same instance.
8772 mutex_lock(&child_ctx->mutex);
8775 * In a single ctx::lock section, de-schedule the events and detach the
8776 * context from the task such that we cannot ever get it scheduled back
8779 raw_spin_lock_irq(&child_ctx->lock);
8780 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8783 * Now that the context is inactive, destroy the task <-> ctx relation
8784 * and mark the context dead.
8786 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
8787 put_ctx(child_ctx); /* cannot be last */
8788 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
8789 put_task_struct(current); /* cannot be last */
8791 clone_ctx = unclone_ctx(child_ctx);
8792 raw_spin_unlock_irq(&child_ctx->lock);
8798 * Report the task dead after unscheduling the events so that we
8799 * won't get any samples after PERF_RECORD_EXIT. We can however still
8800 * get a few PERF_RECORD_READ events.
8802 perf_event_task(child, child_ctx, 0);
8804 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8805 __perf_event_exit_task(child_event, child_ctx, child);
8807 mutex_unlock(&child_ctx->mutex);
8813 * When a child task exits, feed back event values to parent events.
8815 void perf_event_exit_task(struct task_struct *child)
8817 struct perf_event *event, *tmp;
8820 mutex_lock(&child->perf_event_mutex);
8821 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8823 list_del_init(&event->owner_entry);
8826 * Ensure the list deletion is visible before we clear
8827 * the owner, closes a race against perf_release() where
8828 * we need to serialize on the owner->perf_event_mutex.
8831 event->owner = NULL;
8833 mutex_unlock(&child->perf_event_mutex);
8835 for_each_task_context_nr(ctxn)
8836 perf_event_exit_task_context(child, ctxn);
8839 * The perf_event_exit_task_context calls perf_event_task
8840 * with child's task_ctx, which generates EXIT events for
8841 * child contexts and sets child->perf_event_ctxp[] to NULL.
8842 * At this point we need to send EXIT events to cpu contexts.
8844 perf_event_task(child, NULL, 0);
8847 static void perf_free_event(struct perf_event *event,
8848 struct perf_event_context *ctx)
8850 struct perf_event *parent = event->parent;
8852 if (WARN_ON_ONCE(!parent))
8855 mutex_lock(&parent->child_mutex);
8856 list_del_init(&event->child_list);
8857 mutex_unlock(&parent->child_mutex);
8861 raw_spin_lock_irq(&ctx->lock);
8862 perf_group_detach(event);
8863 list_del_event(event, ctx);
8864 raw_spin_unlock_irq(&ctx->lock);
8869 * Free an unexposed, unused context as created by inheritance by
8870 * perf_event_init_task below, used by fork() in case of fail.
8872 * Not all locks are strictly required, but take them anyway to be nice and
8873 * help out with the lockdep assertions.
8875 void perf_event_free_task(struct task_struct *task)
8877 struct perf_event_context *ctx;
8878 struct perf_event *event, *tmp;
8881 for_each_task_context_nr(ctxn) {
8882 ctx = task->perf_event_ctxp[ctxn];
8886 mutex_lock(&ctx->mutex);
8888 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8890 perf_free_event(event, ctx);
8892 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8894 perf_free_event(event, ctx);
8896 if (!list_empty(&ctx->pinned_groups) ||
8897 !list_empty(&ctx->flexible_groups))
8900 mutex_unlock(&ctx->mutex);
8906 void perf_event_delayed_put(struct task_struct *task)
8910 for_each_task_context_nr(ctxn)
8911 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8914 struct file *perf_event_get(unsigned int fd)
8918 file = fget_raw(fd);
8920 return ERR_PTR(-EBADF);
8922 if (file->f_op != &perf_fops) {
8924 return ERR_PTR(-EBADF);
8930 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8933 return ERR_PTR(-EINVAL);
8935 return &event->attr;
8939 * inherit a event from parent task to child task:
8941 static struct perf_event *
8942 inherit_event(struct perf_event *parent_event,
8943 struct task_struct *parent,
8944 struct perf_event_context *parent_ctx,
8945 struct task_struct *child,
8946 struct perf_event *group_leader,
8947 struct perf_event_context *child_ctx)
8949 enum perf_event_active_state parent_state = parent_event->state;
8950 struct perf_event *child_event;
8951 unsigned long flags;
8954 * Instead of creating recursive hierarchies of events,
8955 * we link inherited events back to the original parent,
8956 * which has a filp for sure, which we use as the reference
8959 if (parent_event->parent)
8960 parent_event = parent_event->parent;
8962 child_event = perf_event_alloc(&parent_event->attr,
8965 group_leader, parent_event,
8967 if (IS_ERR(child_event))
8970 if (is_orphaned_event(parent_event) ||
8971 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8972 free_event(child_event);
8979 * Make the child state follow the state of the parent event,
8980 * not its attr.disabled bit. We hold the parent's mutex,
8981 * so we won't race with perf_event_{en, dis}able_family.
8983 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
8984 child_event->state = PERF_EVENT_STATE_INACTIVE;
8986 child_event->state = PERF_EVENT_STATE_OFF;
8988 if (parent_event->attr.freq) {
8989 u64 sample_period = parent_event->hw.sample_period;
8990 struct hw_perf_event *hwc = &child_event->hw;
8992 hwc->sample_period = sample_period;
8993 hwc->last_period = sample_period;
8995 local64_set(&hwc->period_left, sample_period);
8998 child_event->ctx = child_ctx;
8999 child_event->overflow_handler = parent_event->overflow_handler;
9000 child_event->overflow_handler_context
9001 = parent_event->overflow_handler_context;
9004 * Precalculate sample_data sizes
9006 perf_event__header_size(child_event);
9007 perf_event__id_header_size(child_event);
9010 * Link it up in the child's context:
9012 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9013 add_event_to_ctx(child_event, child_ctx);
9014 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9017 * Link this into the parent event's child list
9019 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9020 mutex_lock(&parent_event->child_mutex);
9021 list_add_tail(&child_event->child_list, &parent_event->child_list);
9022 mutex_unlock(&parent_event->child_mutex);
9027 static int inherit_group(struct perf_event *parent_event,
9028 struct task_struct *parent,
9029 struct perf_event_context *parent_ctx,
9030 struct task_struct *child,
9031 struct perf_event_context *child_ctx)
9033 struct perf_event *leader;
9034 struct perf_event *sub;
9035 struct perf_event *child_ctr;
9037 leader = inherit_event(parent_event, parent, parent_ctx,
9038 child, NULL, child_ctx);
9040 return PTR_ERR(leader);
9041 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9042 child_ctr = inherit_event(sub, parent, parent_ctx,
9043 child, leader, child_ctx);
9044 if (IS_ERR(child_ctr))
9045 return PTR_ERR(child_ctr);
9051 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9052 struct perf_event_context *parent_ctx,
9053 struct task_struct *child, int ctxn,
9057 struct perf_event_context *child_ctx;
9059 if (!event->attr.inherit) {
9064 child_ctx = child->perf_event_ctxp[ctxn];
9067 * This is executed from the parent task context, so
9068 * inherit events that have been marked for cloning.
9069 * First allocate and initialize a context for the
9073 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9077 child->perf_event_ctxp[ctxn] = child_ctx;
9080 ret = inherit_group(event, parent, parent_ctx,
9090 * Initialize the perf_event context in task_struct
9092 static int perf_event_init_context(struct task_struct *child, int ctxn)
9094 struct perf_event_context *child_ctx, *parent_ctx;
9095 struct perf_event_context *cloned_ctx;
9096 struct perf_event *event;
9097 struct task_struct *parent = current;
9098 int inherited_all = 1;
9099 unsigned long flags;
9102 if (likely(!parent->perf_event_ctxp[ctxn]))
9106 * If the parent's context is a clone, pin it so it won't get
9109 parent_ctx = perf_pin_task_context(parent, ctxn);
9114 * No need to check if parent_ctx != NULL here; since we saw
9115 * it non-NULL earlier, the only reason for it to become NULL
9116 * is if we exit, and since we're currently in the middle of
9117 * a fork we can't be exiting at the same time.
9121 * Lock the parent list. No need to lock the child - not PID
9122 * hashed yet and not running, so nobody can access it.
9124 mutex_lock(&parent_ctx->mutex);
9127 * We dont have to disable NMIs - we are only looking at
9128 * the list, not manipulating it:
9130 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9131 ret = inherit_task_group(event, parent, parent_ctx,
9132 child, ctxn, &inherited_all);
9138 * We can't hold ctx->lock when iterating the ->flexible_group list due
9139 * to allocations, but we need to prevent rotation because
9140 * rotate_ctx() will change the list from interrupt context.
9142 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9143 parent_ctx->rotate_disable = 1;
9144 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9146 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9147 ret = inherit_task_group(event, parent, parent_ctx,
9148 child, ctxn, &inherited_all);
9153 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9154 parent_ctx->rotate_disable = 0;
9156 child_ctx = child->perf_event_ctxp[ctxn];
9158 if (child_ctx && inherited_all) {
9160 * Mark the child context as a clone of the parent
9161 * context, or of whatever the parent is a clone of.
9163 * Note that if the parent is a clone, the holding of
9164 * parent_ctx->lock avoids it from being uncloned.
9166 cloned_ctx = parent_ctx->parent_ctx;
9168 child_ctx->parent_ctx = cloned_ctx;
9169 child_ctx->parent_gen = parent_ctx->parent_gen;
9171 child_ctx->parent_ctx = parent_ctx;
9172 child_ctx->parent_gen = parent_ctx->generation;
9174 get_ctx(child_ctx->parent_ctx);
9177 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9178 mutex_unlock(&parent_ctx->mutex);
9180 perf_unpin_context(parent_ctx);
9181 put_ctx(parent_ctx);
9187 * Initialize the perf_event context in task_struct
9189 int perf_event_init_task(struct task_struct *child)
9193 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9194 mutex_init(&child->perf_event_mutex);
9195 INIT_LIST_HEAD(&child->perf_event_list);
9197 for_each_task_context_nr(ctxn) {
9198 ret = perf_event_init_context(child, ctxn);
9200 perf_event_free_task(child);
9208 static void __init perf_event_init_all_cpus(void)
9210 struct swevent_htable *swhash;
9213 for_each_possible_cpu(cpu) {
9214 swhash = &per_cpu(swevent_htable, cpu);
9215 mutex_init(&swhash->hlist_mutex);
9216 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9220 static void perf_event_init_cpu(int cpu)
9222 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9224 mutex_lock(&swhash->hlist_mutex);
9225 if (swhash->hlist_refcount > 0) {
9226 struct swevent_hlist *hlist;
9228 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9230 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9232 mutex_unlock(&swhash->hlist_mutex);
9235 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9236 static void __perf_event_exit_context(void *__info)
9238 struct perf_event_context *ctx = __info;
9239 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9240 struct perf_event *event;
9242 raw_spin_lock(&ctx->lock);
9243 list_for_each_entry(event, &ctx->event_list, event_entry)
9244 __perf_remove_from_context(event, cpuctx, ctx, (void *)(unsigned long)true);
9245 raw_spin_unlock(&ctx->lock);
9248 static void perf_event_exit_cpu_context(int cpu)
9250 struct perf_event_context *ctx;
9254 idx = srcu_read_lock(&pmus_srcu);
9255 list_for_each_entry_rcu(pmu, &pmus, entry) {
9256 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9258 mutex_lock(&ctx->mutex);
9259 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9260 mutex_unlock(&ctx->mutex);
9262 srcu_read_unlock(&pmus_srcu, idx);
9265 static void perf_event_exit_cpu(int cpu)
9267 perf_event_exit_cpu_context(cpu);
9270 static inline void perf_event_exit_cpu(int cpu) { }
9274 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9278 for_each_online_cpu(cpu)
9279 perf_event_exit_cpu(cpu);
9285 * Run the perf reboot notifier at the very last possible moment so that
9286 * the generic watchdog code runs as long as possible.
9288 static struct notifier_block perf_reboot_notifier = {
9289 .notifier_call = perf_reboot,
9290 .priority = INT_MIN,
9294 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9296 unsigned int cpu = (long)hcpu;
9298 switch (action & ~CPU_TASKS_FROZEN) {
9300 case CPU_UP_PREPARE:
9301 case CPU_DOWN_FAILED:
9302 perf_event_init_cpu(cpu);
9305 case CPU_UP_CANCELED:
9306 case CPU_DOWN_PREPARE:
9307 perf_event_exit_cpu(cpu);
9316 void __init perf_event_init(void)
9322 perf_event_init_all_cpus();
9323 init_srcu_struct(&pmus_srcu);
9324 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9325 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9326 perf_pmu_register(&perf_task_clock, NULL, -1);
9328 perf_cpu_notifier(perf_cpu_notify);
9329 register_reboot_notifier(&perf_reboot_notifier);
9331 ret = init_hw_breakpoint();
9332 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9334 /* do not patch jump label more than once per second */
9335 jump_label_rate_limit(&perf_sched_events, HZ);
9338 * Build time assertion that we keep the data_head at the intended
9339 * location. IOW, validation we got the __reserved[] size right.
9341 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9345 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9348 struct perf_pmu_events_attr *pmu_attr =
9349 container_of(attr, struct perf_pmu_events_attr, attr);
9351 if (pmu_attr->event_str)
9352 return sprintf(page, "%s\n", pmu_attr->event_str);
9357 static int __init perf_event_sysfs_init(void)
9362 mutex_lock(&pmus_lock);
9364 ret = bus_register(&pmu_bus);
9368 list_for_each_entry(pmu, &pmus, entry) {
9369 if (!pmu->name || pmu->type < 0)
9372 ret = pmu_dev_alloc(pmu);
9373 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9375 pmu_bus_running = 1;
9379 mutex_unlock(&pmus_lock);
9383 device_initcall(perf_event_sysfs_init);
9385 #ifdef CONFIG_CGROUP_PERF
9386 static struct cgroup_subsys_state *
9387 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9389 struct perf_cgroup *jc;
9391 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9393 return ERR_PTR(-ENOMEM);
9395 jc->info = alloc_percpu(struct perf_cgroup_info);
9398 return ERR_PTR(-ENOMEM);
9404 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9406 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9408 free_percpu(jc->info);
9412 static int __perf_cgroup_move(void *info)
9414 struct task_struct *task = info;
9416 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9421 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9423 struct task_struct *task;
9424 struct cgroup_subsys_state *css;
9426 cgroup_taskset_for_each(task, css, tset)
9427 task_function_call(task, __perf_cgroup_move, task);
9430 struct cgroup_subsys perf_event_cgrp_subsys = {
9431 .css_alloc = perf_cgroup_css_alloc,
9432 .css_free = perf_cgroup_css_free,
9433 .attach = perf_cgroup_attach,
9435 #endif /* CONFIG_CGROUP_PERF */