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);
152 * On task ctx scheduling...
154 * When !ctx->nr_events a task context will not be scheduled. This means
155 * we can disable the scheduler hooks (for performance) without leaving
156 * pending task ctx state.
158 * This however results in two special cases:
160 * - removing the last event from a task ctx; this is relatively straight
161 * forward and is done in __perf_remove_from_context.
163 * - adding the first event to a task ctx; this is tricky because we cannot
164 * rely on ctx->is_active and therefore cannot use event_function_call().
165 * See perf_install_in_context().
167 * This is because we need a ctx->lock serialized variable (ctx->is_active)
168 * to reliably determine if a particular task/context is scheduled in. The
169 * task_curr() use in task_function_call() is racy in that a remote context
170 * switch is not a single atomic operation.
172 * As is, the situation is 'safe' because we set rq->curr before we do the
173 * actual context switch. This means that task_curr() will fail early, but
174 * we'll continue spinning on ctx->is_active until we've passed
175 * perf_event_task_sched_out().
177 * Without this ctx->lock serialized variable we could have race where we find
178 * the task (and hence the context) would not be active while in fact they are.
180 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
183 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
184 struct perf_event_context *, void *);
186 struct event_function_struct {
187 struct perf_event *event;
192 static int event_function(void *info)
194 struct event_function_struct *efs = info;
195 struct perf_event *event = efs->event;
196 struct perf_event_context *ctx = event->ctx;
197 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
198 struct perf_event_context *task_ctx = cpuctx->task_ctx;
200 WARN_ON_ONCE(!irqs_disabled());
203 * Since we do the IPI call without holding ctx->lock things can have
204 * changed, double check we hit the task we set out to hit.
206 * If ctx->task == current, we know things must remain valid because
207 * we have IRQs disabled so we cannot schedule.
210 if (ctx->task != current)
213 WARN_ON_ONCE(task_ctx != ctx);
215 WARN_ON_ONCE(&cpuctx->ctx != ctx);
218 perf_ctx_lock(cpuctx, task_ctx);
220 * Now that we hold locks, double check state. Paranoia pays.
223 WARN_ON_ONCE(task_ctx->task != current);
225 * We only use event_function_call() on established contexts,
226 * and event_function() is only ever called when active (or
227 * rather, we'll have bailed in task_function_call() or the
228 * above ctx->task != current test), therefore we must have
229 * ctx->is_active here.
231 WARN_ON_ONCE(!ctx->is_active);
233 * And since we have ctx->is_active, cpuctx->task_ctx must
236 WARN_ON_ONCE(cpuctx->task_ctx != task_ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
239 perf_ctx_unlock(cpuctx, task_ctx);
244 static void event_function_local(struct perf_event *event, event_f func, void *data)
246 struct event_function_struct efs = {
252 int ret = event_function(&efs);
256 static void event_function_call(struct perf_event *event, event_f func, void *data)
258 struct perf_event_context *ctx = event->ctx;
259 struct task_struct *task = ctx->task;
260 struct event_function_struct efs = {
266 if (!event->parent) {
268 * If this is a !child event, we must hold ctx::mutex to
269 * stabilize the the event->ctx relation. See
270 * perf_event_ctx_lock().
272 lockdep_assert_held(&ctx->mutex);
276 cpu_function_call(event->cpu, event_function, &efs);
281 if (!task_function_call(task, event_function, &efs))
284 raw_spin_lock_irq(&ctx->lock);
285 if (ctx->is_active) {
287 * Reload the task pointer, it might have been changed by
288 * a concurrent perf_event_context_sched_out().
291 raw_spin_unlock_irq(&ctx->lock);
294 func(event, NULL, ctx, data);
295 raw_spin_unlock_irq(&ctx->lock);
298 #define EVENT_OWNER_KERNEL ((void *) -1)
300 static bool is_kernel_event(struct perf_event *event)
302 return event->owner == EVENT_OWNER_KERNEL;
305 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
306 PERF_FLAG_FD_OUTPUT |\
307 PERF_FLAG_PID_CGROUP |\
308 PERF_FLAG_FD_CLOEXEC)
311 * branch priv levels that need permission checks
313 #define PERF_SAMPLE_BRANCH_PERM_PLM \
314 (PERF_SAMPLE_BRANCH_KERNEL |\
315 PERF_SAMPLE_BRANCH_HV)
318 EVENT_FLEXIBLE = 0x1,
320 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
324 * perf_sched_events : >0 events exist
325 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
327 struct static_key_deferred perf_sched_events __read_mostly;
328 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
329 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
331 static atomic_t nr_mmap_events __read_mostly;
332 static atomic_t nr_comm_events __read_mostly;
333 static atomic_t nr_task_events __read_mostly;
334 static atomic_t nr_freq_events __read_mostly;
335 static atomic_t nr_switch_events __read_mostly;
337 static LIST_HEAD(pmus);
338 static DEFINE_MUTEX(pmus_lock);
339 static struct srcu_struct pmus_srcu;
342 * perf event paranoia level:
343 * -1 - not paranoid at all
344 * 0 - disallow raw tracepoint access for unpriv
345 * 1 - disallow cpu events for unpriv
346 * 2 - disallow kernel profiling for unpriv
348 int sysctl_perf_event_paranoid __read_mostly = 1;
350 /* Minimum for 512 kiB + 1 user control page */
351 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
354 * max perf event sample rate
356 #define DEFAULT_MAX_SAMPLE_RATE 100000
357 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
358 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
360 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
362 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
363 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
365 static int perf_sample_allowed_ns __read_mostly =
366 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
368 static void update_perf_cpu_limits(void)
370 u64 tmp = perf_sample_period_ns;
372 tmp *= sysctl_perf_cpu_time_max_percent;
374 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
377 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
379 int perf_proc_update_handler(struct ctl_table *table, int write,
380 void __user *buffer, size_t *lenp,
383 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
388 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
389 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
390 update_perf_cpu_limits();
395 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
397 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
398 void __user *buffer, size_t *lenp,
401 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
406 update_perf_cpu_limits();
412 * perf samples are done in some very critical code paths (NMIs).
413 * If they take too much CPU time, the system can lock up and not
414 * get any real work done. This will drop the sample rate when
415 * we detect that events are taking too long.
417 #define NR_ACCUMULATED_SAMPLES 128
418 static DEFINE_PER_CPU(u64, running_sample_length);
420 static void perf_duration_warn(struct irq_work *w)
422 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
423 u64 avg_local_sample_len;
424 u64 local_samples_len;
426 local_samples_len = __this_cpu_read(running_sample_length);
427 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
429 printk_ratelimited(KERN_WARNING
430 "perf interrupt took too long (%lld > %lld), lowering "
431 "kernel.perf_event_max_sample_rate to %d\n",
432 avg_local_sample_len, allowed_ns >> 1,
433 sysctl_perf_event_sample_rate);
436 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
438 void perf_sample_event_took(u64 sample_len_ns)
440 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
441 u64 avg_local_sample_len;
442 u64 local_samples_len;
447 /* decay the counter by 1 average sample */
448 local_samples_len = __this_cpu_read(running_sample_length);
449 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
450 local_samples_len += sample_len_ns;
451 __this_cpu_write(running_sample_length, local_samples_len);
454 * note: this will be biased artifically low until we have
455 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
456 * from having to maintain a count.
458 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
460 if (avg_local_sample_len <= allowed_ns)
463 if (max_samples_per_tick <= 1)
466 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
467 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
468 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
470 update_perf_cpu_limits();
472 if (!irq_work_queue(&perf_duration_work)) {
473 early_printk("perf interrupt took too long (%lld > %lld), lowering "
474 "kernel.perf_event_max_sample_rate to %d\n",
475 avg_local_sample_len, allowed_ns >> 1,
476 sysctl_perf_event_sample_rate);
480 static atomic64_t perf_event_id;
482 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
483 enum event_type_t event_type);
485 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
486 enum event_type_t event_type,
487 struct task_struct *task);
489 static void update_context_time(struct perf_event_context *ctx);
490 static u64 perf_event_time(struct perf_event *event);
492 void __weak perf_event_print_debug(void) { }
494 extern __weak const char *perf_pmu_name(void)
499 static inline u64 perf_clock(void)
501 return local_clock();
504 static inline u64 perf_event_clock(struct perf_event *event)
506 return event->clock();
509 #ifdef CONFIG_CGROUP_PERF
512 perf_cgroup_match(struct perf_event *event)
514 struct perf_event_context *ctx = event->ctx;
515 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
517 /* @event doesn't care about cgroup */
521 /* wants specific cgroup scope but @cpuctx isn't associated with any */
526 * Cgroup scoping is recursive. An event enabled for a cgroup is
527 * also enabled for all its descendant cgroups. If @cpuctx's
528 * cgroup is a descendant of @event's (the test covers identity
529 * case), it's a match.
531 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
532 event->cgrp->css.cgroup);
535 static inline void perf_detach_cgroup(struct perf_event *event)
537 css_put(&event->cgrp->css);
541 static inline int is_cgroup_event(struct perf_event *event)
543 return event->cgrp != NULL;
546 static inline u64 perf_cgroup_event_time(struct perf_event *event)
548 struct perf_cgroup_info *t;
550 t = per_cpu_ptr(event->cgrp->info, event->cpu);
554 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
556 struct perf_cgroup_info *info;
561 info = this_cpu_ptr(cgrp->info);
563 info->time += now - info->timestamp;
564 info->timestamp = now;
567 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
569 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
571 __update_cgrp_time(cgrp_out);
574 static inline void update_cgrp_time_from_event(struct perf_event *event)
576 struct perf_cgroup *cgrp;
579 * ensure we access cgroup data only when needed and
580 * when we know the cgroup is pinned (css_get)
582 if (!is_cgroup_event(event))
585 cgrp = perf_cgroup_from_task(current, event->ctx);
587 * Do not update time when cgroup is not active
589 if (cgrp == event->cgrp)
590 __update_cgrp_time(event->cgrp);
594 perf_cgroup_set_timestamp(struct task_struct *task,
595 struct perf_event_context *ctx)
597 struct perf_cgroup *cgrp;
598 struct perf_cgroup_info *info;
601 * ctx->lock held by caller
602 * ensure we do not access cgroup data
603 * unless we have the cgroup pinned (css_get)
605 if (!task || !ctx->nr_cgroups)
608 cgrp = perf_cgroup_from_task(task, ctx);
609 info = this_cpu_ptr(cgrp->info);
610 info->timestamp = ctx->timestamp;
613 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
614 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
617 * reschedule events based on the cgroup constraint of task.
619 * mode SWOUT : schedule out everything
620 * mode SWIN : schedule in based on cgroup for next
622 static void perf_cgroup_switch(struct task_struct *task, int mode)
624 struct perf_cpu_context *cpuctx;
629 * disable interrupts to avoid geting nr_cgroup
630 * changes via __perf_event_disable(). Also
633 local_irq_save(flags);
636 * we reschedule only in the presence of cgroup
637 * constrained events.
640 list_for_each_entry_rcu(pmu, &pmus, entry) {
641 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
642 if (cpuctx->unique_pmu != pmu)
643 continue; /* ensure we process each cpuctx once */
646 * perf_cgroup_events says at least one
647 * context on this CPU has cgroup events.
649 * ctx->nr_cgroups reports the number of cgroup
650 * events for a context.
652 if (cpuctx->ctx.nr_cgroups > 0) {
653 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
654 perf_pmu_disable(cpuctx->ctx.pmu);
656 if (mode & PERF_CGROUP_SWOUT) {
657 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
659 * must not be done before ctxswout due
660 * to event_filter_match() in event_sched_out()
665 if (mode & PERF_CGROUP_SWIN) {
666 WARN_ON_ONCE(cpuctx->cgrp);
668 * set cgrp before ctxsw in to allow
669 * event_filter_match() to not have to pass
671 * we pass the cpuctx->ctx to perf_cgroup_from_task()
672 * because cgorup events are only per-cpu
674 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
675 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
677 perf_pmu_enable(cpuctx->ctx.pmu);
678 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
682 local_irq_restore(flags);
685 static inline void perf_cgroup_sched_out(struct task_struct *task,
686 struct task_struct *next)
688 struct perf_cgroup *cgrp1;
689 struct perf_cgroup *cgrp2 = NULL;
693 * we come here when we know perf_cgroup_events > 0
694 * we do not need to pass the ctx here because we know
695 * we are holding the rcu lock
697 cgrp1 = perf_cgroup_from_task(task, NULL);
698 cgrp2 = perf_cgroup_from_task(next, NULL);
701 * only schedule out current cgroup events if we know
702 * that we are switching to a different cgroup. Otherwise,
703 * do no touch the cgroup events.
706 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
711 static inline void perf_cgroup_sched_in(struct task_struct *prev,
712 struct task_struct *task)
714 struct perf_cgroup *cgrp1;
715 struct perf_cgroup *cgrp2 = NULL;
719 * we come here when we know perf_cgroup_events > 0
720 * we do not need to pass the ctx here because we know
721 * we are holding the rcu lock
723 cgrp1 = perf_cgroup_from_task(task, NULL);
724 cgrp2 = perf_cgroup_from_task(prev, NULL);
727 * only need to schedule in cgroup events if we are changing
728 * cgroup during ctxsw. Cgroup events were not scheduled
729 * out of ctxsw out if that was not the case.
732 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
737 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
738 struct perf_event_attr *attr,
739 struct perf_event *group_leader)
741 struct perf_cgroup *cgrp;
742 struct cgroup_subsys_state *css;
743 struct fd f = fdget(fd);
749 css = css_tryget_online_from_dir(f.file->f_path.dentry,
750 &perf_event_cgrp_subsys);
756 cgrp = container_of(css, struct perf_cgroup, css);
760 * all events in a group must monitor
761 * the same cgroup because a task belongs
762 * to only one perf cgroup at a time
764 if (group_leader && group_leader->cgrp != cgrp) {
765 perf_detach_cgroup(event);
774 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
776 struct perf_cgroup_info *t;
777 t = per_cpu_ptr(event->cgrp->info, event->cpu);
778 event->shadow_ctx_time = now - t->timestamp;
782 perf_cgroup_defer_enabled(struct perf_event *event)
785 * when the current task's perf cgroup does not match
786 * the event's, we need to remember to call the
787 * perf_mark_enable() function the first time a task with
788 * a matching perf cgroup is scheduled in.
790 if (is_cgroup_event(event) && !perf_cgroup_match(event))
791 event->cgrp_defer_enabled = 1;
795 perf_cgroup_mark_enabled(struct perf_event *event,
796 struct perf_event_context *ctx)
798 struct perf_event *sub;
799 u64 tstamp = perf_event_time(event);
801 if (!event->cgrp_defer_enabled)
804 event->cgrp_defer_enabled = 0;
806 event->tstamp_enabled = tstamp - event->total_time_enabled;
807 list_for_each_entry(sub, &event->sibling_list, group_entry) {
808 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
809 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
810 sub->cgrp_defer_enabled = 0;
814 #else /* !CONFIG_CGROUP_PERF */
817 perf_cgroup_match(struct perf_event *event)
822 static inline void perf_detach_cgroup(struct perf_event *event)
825 static inline int is_cgroup_event(struct perf_event *event)
830 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
835 static inline void update_cgrp_time_from_event(struct perf_event *event)
839 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
843 static inline void perf_cgroup_sched_out(struct task_struct *task,
844 struct task_struct *next)
848 static inline void perf_cgroup_sched_in(struct task_struct *prev,
849 struct task_struct *task)
853 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
854 struct perf_event_attr *attr,
855 struct perf_event *group_leader)
861 perf_cgroup_set_timestamp(struct task_struct *task,
862 struct perf_event_context *ctx)
867 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
872 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
876 static inline u64 perf_cgroup_event_time(struct perf_event *event)
882 perf_cgroup_defer_enabled(struct perf_event *event)
887 perf_cgroup_mark_enabled(struct perf_event *event,
888 struct perf_event_context *ctx)
894 * set default to be dependent on timer tick just
897 #define PERF_CPU_HRTIMER (1000 / HZ)
899 * function must be called with interrupts disbled
901 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
903 struct perf_cpu_context *cpuctx;
906 WARN_ON(!irqs_disabled());
908 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
909 rotations = perf_rotate_context(cpuctx);
911 raw_spin_lock(&cpuctx->hrtimer_lock);
913 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
915 cpuctx->hrtimer_active = 0;
916 raw_spin_unlock(&cpuctx->hrtimer_lock);
918 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
921 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
923 struct hrtimer *timer = &cpuctx->hrtimer;
924 struct pmu *pmu = cpuctx->ctx.pmu;
927 /* no multiplexing needed for SW PMU */
928 if (pmu->task_ctx_nr == perf_sw_context)
932 * check default is sane, if not set then force to
933 * default interval (1/tick)
935 interval = pmu->hrtimer_interval_ms;
937 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
939 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
941 raw_spin_lock_init(&cpuctx->hrtimer_lock);
942 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
943 timer->function = perf_mux_hrtimer_handler;
946 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
948 struct hrtimer *timer = &cpuctx->hrtimer;
949 struct pmu *pmu = cpuctx->ctx.pmu;
953 if (pmu->task_ctx_nr == perf_sw_context)
956 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
957 if (!cpuctx->hrtimer_active) {
958 cpuctx->hrtimer_active = 1;
959 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
960 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
962 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
967 void perf_pmu_disable(struct pmu *pmu)
969 int *count = this_cpu_ptr(pmu->pmu_disable_count);
971 pmu->pmu_disable(pmu);
974 void perf_pmu_enable(struct pmu *pmu)
976 int *count = this_cpu_ptr(pmu->pmu_disable_count);
978 pmu->pmu_enable(pmu);
981 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
984 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
985 * perf_event_task_tick() are fully serialized because they're strictly cpu
986 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
987 * disabled, while perf_event_task_tick is called from IRQ context.
989 static void perf_event_ctx_activate(struct perf_event_context *ctx)
991 struct list_head *head = this_cpu_ptr(&active_ctx_list);
993 WARN_ON(!irqs_disabled());
995 WARN_ON(!list_empty(&ctx->active_ctx_list));
997 list_add(&ctx->active_ctx_list, head);
1000 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1002 WARN_ON(!irqs_disabled());
1004 WARN_ON(list_empty(&ctx->active_ctx_list));
1006 list_del_init(&ctx->active_ctx_list);
1009 static void get_ctx(struct perf_event_context *ctx)
1011 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1014 static void free_ctx(struct rcu_head *head)
1016 struct perf_event_context *ctx;
1018 ctx = container_of(head, struct perf_event_context, rcu_head);
1019 kfree(ctx->task_ctx_data);
1023 static void put_ctx(struct perf_event_context *ctx)
1025 if (atomic_dec_and_test(&ctx->refcount)) {
1026 if (ctx->parent_ctx)
1027 put_ctx(ctx->parent_ctx);
1029 put_task_struct(ctx->task);
1030 call_rcu(&ctx->rcu_head, free_ctx);
1035 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1036 * perf_pmu_migrate_context() we need some magic.
1038 * Those places that change perf_event::ctx will hold both
1039 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1041 * Lock ordering is by mutex address. There are two other sites where
1042 * perf_event_context::mutex nests and those are:
1044 * - perf_event_exit_task_context() [ child , 0 ]
1045 * __perf_event_exit_task()
1046 * sync_child_event()
1047 * put_event() [ parent, 1 ]
1049 * - perf_event_init_context() [ parent, 0 ]
1050 * inherit_task_group()
1053 * perf_event_alloc()
1055 * perf_try_init_event() [ child , 1 ]
1057 * While it appears there is an obvious deadlock here -- the parent and child
1058 * nesting levels are inverted between the two. This is in fact safe because
1059 * life-time rules separate them. That is an exiting task cannot fork, and a
1060 * spawning task cannot (yet) exit.
1062 * But remember that that these are parent<->child context relations, and
1063 * migration does not affect children, therefore these two orderings should not
1066 * The change in perf_event::ctx does not affect children (as claimed above)
1067 * because the sys_perf_event_open() case will install a new event and break
1068 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1069 * concerned with cpuctx and that doesn't have children.
1071 * The places that change perf_event::ctx will issue:
1073 * perf_remove_from_context();
1074 * synchronize_rcu();
1075 * perf_install_in_context();
1077 * to affect the change. The remove_from_context() + synchronize_rcu() should
1078 * quiesce the event, after which we can install it in the new location. This
1079 * means that only external vectors (perf_fops, prctl) can perturb the event
1080 * while in transit. Therefore all such accessors should also acquire
1081 * perf_event_context::mutex to serialize against this.
1083 * However; because event->ctx can change while we're waiting to acquire
1084 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1088 * task_struct::perf_event_mutex
1089 * perf_event_context::mutex
1090 * perf_event_context::lock
1091 * perf_event::child_mutex;
1092 * perf_event::mmap_mutex
1095 static struct perf_event_context *
1096 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1098 struct perf_event_context *ctx;
1102 ctx = ACCESS_ONCE(event->ctx);
1103 if (!atomic_inc_not_zero(&ctx->refcount)) {
1109 mutex_lock_nested(&ctx->mutex, nesting);
1110 if (event->ctx != ctx) {
1111 mutex_unlock(&ctx->mutex);
1119 static inline struct perf_event_context *
1120 perf_event_ctx_lock(struct perf_event *event)
1122 return perf_event_ctx_lock_nested(event, 0);
1125 static void perf_event_ctx_unlock(struct perf_event *event,
1126 struct perf_event_context *ctx)
1128 mutex_unlock(&ctx->mutex);
1133 * This must be done under the ctx->lock, such as to serialize against
1134 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1135 * calling scheduler related locks and ctx->lock nests inside those.
1137 static __must_check struct perf_event_context *
1138 unclone_ctx(struct perf_event_context *ctx)
1140 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1142 lockdep_assert_held(&ctx->lock);
1145 ctx->parent_ctx = NULL;
1151 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1154 * only top level events have the pid namespace they were created in
1157 event = event->parent;
1159 return task_tgid_nr_ns(p, event->ns);
1162 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1165 * only top level events have the pid namespace they were created in
1168 event = event->parent;
1170 return task_pid_nr_ns(p, event->ns);
1174 * If we inherit events we want to return the parent event id
1177 static u64 primary_event_id(struct perf_event *event)
1182 id = event->parent->id;
1188 * 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 (!atomic_inc_not_zero(&ctx->refcount)) {
1230 raw_spin_unlock(&ctx->lock);
1236 local_irq_restore(*flags);
1241 * Get the context for a task and increment its pin_count so it
1242 * can't get swapped to another task. This also increments its
1243 * reference count so that the context can't get freed.
1245 static struct perf_event_context *
1246 perf_pin_task_context(struct task_struct *task, int ctxn)
1248 struct perf_event_context *ctx;
1249 unsigned long flags;
1251 ctx = perf_lock_task_context(task, ctxn, &flags);
1254 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1259 static void perf_unpin_context(struct perf_event_context *ctx)
1261 unsigned long flags;
1263 raw_spin_lock_irqsave(&ctx->lock, flags);
1265 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1269 * Update the record of the current time in a context.
1271 static void update_context_time(struct perf_event_context *ctx)
1273 u64 now = perf_clock();
1275 ctx->time += now - ctx->timestamp;
1276 ctx->timestamp = now;
1279 static u64 perf_event_time(struct perf_event *event)
1281 struct perf_event_context *ctx = event->ctx;
1283 if (is_cgroup_event(event))
1284 return perf_cgroup_event_time(event);
1286 return ctx ? ctx->time : 0;
1290 * Update the total_time_enabled and total_time_running fields for a event.
1291 * The caller of this function needs to hold the ctx->lock.
1293 static void update_event_times(struct perf_event *event)
1295 struct perf_event_context *ctx = event->ctx;
1298 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1299 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1302 * in cgroup mode, time_enabled represents
1303 * the time the event was enabled AND active
1304 * tasks were in the monitored cgroup. This is
1305 * independent of the activity of the context as
1306 * there may be a mix of cgroup and non-cgroup events.
1308 * That is why we treat cgroup events differently
1311 if (is_cgroup_event(event))
1312 run_end = perf_cgroup_event_time(event);
1313 else if (ctx->is_active)
1314 run_end = ctx->time;
1316 run_end = event->tstamp_stopped;
1318 event->total_time_enabled = run_end - event->tstamp_enabled;
1320 if (event->state == PERF_EVENT_STATE_INACTIVE)
1321 run_end = event->tstamp_stopped;
1323 run_end = perf_event_time(event);
1325 event->total_time_running = run_end - event->tstamp_running;
1330 * Update total_time_enabled and total_time_running for all events in a group.
1332 static void update_group_times(struct perf_event *leader)
1334 struct perf_event *event;
1336 update_event_times(leader);
1337 list_for_each_entry(event, &leader->sibling_list, group_entry)
1338 update_event_times(event);
1341 static struct list_head *
1342 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1344 if (event->attr.pinned)
1345 return &ctx->pinned_groups;
1347 return &ctx->flexible_groups;
1351 * Add a event from the lists for its context.
1352 * Must be called with ctx->mutex and ctx->lock held.
1355 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1357 lockdep_assert_held(&ctx->lock);
1359 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1360 event->attach_state |= PERF_ATTACH_CONTEXT;
1363 * If we're a stand alone event or group leader, we go to the context
1364 * list, group events are kept attached to the group so that
1365 * perf_group_detach can, at all times, locate all siblings.
1367 if (event->group_leader == event) {
1368 struct list_head *list;
1370 if (is_software_event(event))
1371 event->group_flags |= PERF_GROUP_SOFTWARE;
1373 list = ctx_group_list(event, ctx);
1374 list_add_tail(&event->group_entry, list);
1377 if (is_cgroup_event(event))
1380 list_add_rcu(&event->event_entry, &ctx->event_list);
1382 if (event->attr.inherit_stat)
1389 * Initialize event state based on the perf_event_attr::disabled.
1391 static inline void perf_event__state_init(struct perf_event *event)
1393 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1394 PERF_EVENT_STATE_INACTIVE;
1397 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1399 int entry = sizeof(u64); /* value */
1403 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1404 size += sizeof(u64);
1406 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1407 size += sizeof(u64);
1409 if (event->attr.read_format & PERF_FORMAT_ID)
1410 entry += sizeof(u64);
1412 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1414 size += sizeof(u64);
1418 event->read_size = size;
1421 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1423 struct perf_sample_data *data;
1426 if (sample_type & PERF_SAMPLE_IP)
1427 size += sizeof(data->ip);
1429 if (sample_type & PERF_SAMPLE_ADDR)
1430 size += sizeof(data->addr);
1432 if (sample_type & PERF_SAMPLE_PERIOD)
1433 size += sizeof(data->period);
1435 if (sample_type & PERF_SAMPLE_WEIGHT)
1436 size += sizeof(data->weight);
1438 if (sample_type & PERF_SAMPLE_READ)
1439 size += event->read_size;
1441 if (sample_type & PERF_SAMPLE_DATA_SRC)
1442 size += sizeof(data->data_src.val);
1444 if (sample_type & PERF_SAMPLE_TRANSACTION)
1445 size += sizeof(data->txn);
1447 event->header_size = size;
1451 * Called at perf_event creation and when events are attached/detached from a
1454 static void perf_event__header_size(struct perf_event *event)
1456 __perf_event_read_size(event,
1457 event->group_leader->nr_siblings);
1458 __perf_event_header_size(event, event->attr.sample_type);
1461 static void perf_event__id_header_size(struct perf_event *event)
1463 struct perf_sample_data *data;
1464 u64 sample_type = event->attr.sample_type;
1467 if (sample_type & PERF_SAMPLE_TID)
1468 size += sizeof(data->tid_entry);
1470 if (sample_type & PERF_SAMPLE_TIME)
1471 size += sizeof(data->time);
1473 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1474 size += sizeof(data->id);
1476 if (sample_type & PERF_SAMPLE_ID)
1477 size += sizeof(data->id);
1479 if (sample_type & PERF_SAMPLE_STREAM_ID)
1480 size += sizeof(data->stream_id);
1482 if (sample_type & PERF_SAMPLE_CPU)
1483 size += sizeof(data->cpu_entry);
1485 event->id_header_size = size;
1488 static bool perf_event_validate_size(struct perf_event *event)
1491 * The values computed here will be over-written when we actually
1494 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1495 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1496 perf_event__id_header_size(event);
1499 * Sum the lot; should not exceed the 64k limit we have on records.
1500 * Conservative limit to allow for callchains and other variable fields.
1502 if (event->read_size + event->header_size +
1503 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1509 static void perf_group_attach(struct perf_event *event)
1511 struct perf_event *group_leader = event->group_leader, *pos;
1514 * We can have double attach due to group movement in perf_event_open.
1516 if (event->attach_state & PERF_ATTACH_GROUP)
1519 event->attach_state |= PERF_ATTACH_GROUP;
1521 if (group_leader == event)
1524 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1526 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1527 !is_software_event(event))
1528 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1530 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1531 group_leader->nr_siblings++;
1533 perf_event__header_size(group_leader);
1535 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1536 perf_event__header_size(pos);
1540 * Remove a event from the lists for its context.
1541 * Must be called with ctx->mutex and ctx->lock held.
1544 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1546 struct perf_cpu_context *cpuctx;
1548 WARN_ON_ONCE(event->ctx != ctx);
1549 lockdep_assert_held(&ctx->lock);
1552 * We can have double detach due to exit/hot-unplug + close.
1554 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1557 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1559 if (is_cgroup_event(event)) {
1562 * Because cgroup events are always per-cpu events, this will
1563 * always be called from the right CPU.
1565 cpuctx = __get_cpu_context(ctx);
1567 * If there are no more cgroup events then clear cgrp to avoid
1568 * stale pointer in update_cgrp_time_from_cpuctx().
1570 if (!ctx->nr_cgroups)
1571 cpuctx->cgrp = NULL;
1575 if (event->attr.inherit_stat)
1578 list_del_rcu(&event->event_entry);
1580 if (event->group_leader == event)
1581 list_del_init(&event->group_entry);
1583 update_group_times(event);
1586 * If event was in error state, then keep it
1587 * that way, otherwise bogus counts will be
1588 * returned on read(). The only way to get out
1589 * of error state is by explicit re-enabling
1592 if (event->state > PERF_EVENT_STATE_OFF)
1593 event->state = PERF_EVENT_STATE_OFF;
1598 static void perf_group_detach(struct perf_event *event)
1600 struct perf_event *sibling, *tmp;
1601 struct list_head *list = NULL;
1604 * We can have double detach due to exit/hot-unplug + close.
1606 if (!(event->attach_state & PERF_ATTACH_GROUP))
1609 event->attach_state &= ~PERF_ATTACH_GROUP;
1612 * If this is a sibling, remove it from its group.
1614 if (event->group_leader != event) {
1615 list_del_init(&event->group_entry);
1616 event->group_leader->nr_siblings--;
1620 if (!list_empty(&event->group_entry))
1621 list = &event->group_entry;
1624 * If this was a group event with sibling events then
1625 * upgrade the siblings to singleton events by adding them
1626 * to whatever list we are on.
1628 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1630 list_move_tail(&sibling->group_entry, list);
1631 sibling->group_leader = sibling;
1633 /* Inherit group flags from the previous leader */
1634 sibling->group_flags = event->group_flags;
1636 WARN_ON_ONCE(sibling->ctx != event->ctx);
1640 perf_event__header_size(event->group_leader);
1642 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1643 perf_event__header_size(tmp);
1647 * User event without the task.
1649 static bool is_orphaned_event(struct perf_event *event)
1651 return event && !is_kernel_event(event) && !event->owner;
1655 * Event has a parent but parent's task finished and it's
1656 * alive only because of children holding refference.
1658 static bool is_orphaned_child(struct perf_event *event)
1660 return is_orphaned_event(event->parent);
1663 static void orphans_remove_work(struct work_struct *work);
1665 static void schedule_orphans_remove(struct perf_event_context *ctx)
1667 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1670 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1672 ctx->orphans_remove_sched = true;
1676 static int __init perf_workqueue_init(void)
1678 perf_wq = create_singlethread_workqueue("perf");
1679 WARN(!perf_wq, "failed to create perf workqueue\n");
1680 return perf_wq ? 0 : -1;
1683 core_initcall(perf_workqueue_init);
1685 static inline int pmu_filter_match(struct perf_event *event)
1687 struct pmu *pmu = event->pmu;
1688 return pmu->filter_match ? pmu->filter_match(event) : 1;
1692 event_filter_match(struct perf_event *event)
1694 return (event->cpu == -1 || event->cpu == smp_processor_id())
1695 && perf_cgroup_match(event) && pmu_filter_match(event);
1699 event_sched_out(struct perf_event *event,
1700 struct perf_cpu_context *cpuctx,
1701 struct perf_event_context *ctx)
1703 u64 tstamp = perf_event_time(event);
1706 WARN_ON_ONCE(event->ctx != ctx);
1707 lockdep_assert_held(&ctx->lock);
1710 * An event which could not be activated because of
1711 * filter mismatch still needs to have its timings
1712 * maintained, otherwise bogus information is return
1713 * via read() for time_enabled, time_running:
1715 if (event->state == PERF_EVENT_STATE_INACTIVE
1716 && !event_filter_match(event)) {
1717 delta = tstamp - event->tstamp_stopped;
1718 event->tstamp_running += delta;
1719 event->tstamp_stopped = tstamp;
1722 if (event->state != PERF_EVENT_STATE_ACTIVE)
1725 perf_pmu_disable(event->pmu);
1727 event->state = PERF_EVENT_STATE_INACTIVE;
1728 if (event->pending_disable) {
1729 event->pending_disable = 0;
1730 event->state = PERF_EVENT_STATE_OFF;
1732 event->tstamp_stopped = tstamp;
1733 event->pmu->del(event, 0);
1736 if (!is_software_event(event))
1737 cpuctx->active_oncpu--;
1738 if (!--ctx->nr_active)
1739 perf_event_ctx_deactivate(ctx);
1740 if (event->attr.freq && event->attr.sample_freq)
1742 if (event->attr.exclusive || !cpuctx->active_oncpu)
1743 cpuctx->exclusive = 0;
1745 if (is_orphaned_child(event))
1746 schedule_orphans_remove(ctx);
1748 perf_pmu_enable(event->pmu);
1752 group_sched_out(struct perf_event *group_event,
1753 struct perf_cpu_context *cpuctx,
1754 struct perf_event_context *ctx)
1756 struct perf_event *event;
1757 int state = group_event->state;
1759 event_sched_out(group_event, cpuctx, ctx);
1762 * Schedule out siblings (if any):
1764 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1765 event_sched_out(event, cpuctx, ctx);
1767 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1768 cpuctx->exclusive = 0;
1772 * Cross CPU call to remove a performance event
1774 * We disable the event on the hardware level first. After that we
1775 * remove it from the context list.
1778 __perf_remove_from_context(struct perf_event *event,
1779 struct perf_cpu_context *cpuctx,
1780 struct perf_event_context *ctx,
1783 bool detach_group = (unsigned long)info;
1785 event_sched_out(event, cpuctx, ctx);
1787 perf_group_detach(event);
1788 list_del_event(event, ctx);
1790 if (!ctx->nr_events && ctx->is_active) {
1793 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1794 cpuctx->task_ctx = NULL;
1800 * Remove the event from a task's (or a CPU's) list of events.
1802 * If event->ctx is a cloned context, callers must make sure that
1803 * every task struct that event->ctx->task could possibly point to
1804 * remains valid. This is OK when called from perf_release since
1805 * that only calls us on the top-level context, which can't be a clone.
1806 * When called from perf_event_exit_task, it's OK because the
1807 * context has been detached from its task.
1809 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1811 lockdep_assert_held(&event->ctx->mutex);
1813 event_function_call(event, __perf_remove_from_context,
1814 (void *)(unsigned long)detach_group);
1818 * Cross CPU call to disable a performance event
1820 static void __perf_event_disable(struct perf_event *event,
1821 struct perf_cpu_context *cpuctx,
1822 struct perf_event_context *ctx,
1825 if (event->state < PERF_EVENT_STATE_INACTIVE)
1828 update_context_time(ctx);
1829 update_cgrp_time_from_event(event);
1830 update_group_times(event);
1831 if (event == event->group_leader)
1832 group_sched_out(event, cpuctx, ctx);
1834 event_sched_out(event, cpuctx, ctx);
1835 event->state = PERF_EVENT_STATE_OFF;
1841 * If event->ctx is a cloned context, callers must make sure that
1842 * every task struct that event->ctx->task could possibly point to
1843 * remains valid. This condition is satisifed when called through
1844 * perf_event_for_each_child or perf_event_for_each because they
1845 * hold the top-level event's child_mutex, so any descendant that
1846 * goes to exit will block in sync_child_event.
1847 * When called from perf_pending_event it's OK because event->ctx
1848 * is the current context on this CPU and preemption is disabled,
1849 * hence we can't get into perf_event_task_sched_out for this context.
1851 static void _perf_event_disable(struct perf_event *event)
1853 struct perf_event_context *ctx = event->ctx;
1855 raw_spin_lock_irq(&ctx->lock);
1856 if (event->state <= PERF_EVENT_STATE_OFF) {
1857 raw_spin_unlock_irq(&ctx->lock);
1860 raw_spin_unlock_irq(&ctx->lock);
1862 event_function_call(event, __perf_event_disable, NULL);
1865 void perf_event_disable_local(struct perf_event *event)
1867 event_function_local(event, __perf_event_disable, NULL);
1871 * Strictly speaking kernel users cannot create groups and therefore this
1872 * interface does not need the perf_event_ctx_lock() magic.
1874 void perf_event_disable(struct perf_event *event)
1876 struct perf_event_context *ctx;
1878 ctx = perf_event_ctx_lock(event);
1879 _perf_event_disable(event);
1880 perf_event_ctx_unlock(event, ctx);
1882 EXPORT_SYMBOL_GPL(perf_event_disable);
1884 static void perf_set_shadow_time(struct perf_event *event,
1885 struct perf_event_context *ctx,
1889 * use the correct time source for the time snapshot
1891 * We could get by without this by leveraging the
1892 * fact that to get to this function, the caller
1893 * has most likely already called update_context_time()
1894 * and update_cgrp_time_xx() and thus both timestamp
1895 * are identical (or very close). Given that tstamp is,
1896 * already adjusted for cgroup, we could say that:
1897 * tstamp - ctx->timestamp
1899 * tstamp - cgrp->timestamp.
1901 * Then, in perf_output_read(), the calculation would
1902 * work with no changes because:
1903 * - event is guaranteed scheduled in
1904 * - no scheduled out in between
1905 * - thus the timestamp would be the same
1907 * But this is a bit hairy.
1909 * So instead, we have an explicit cgroup call to remain
1910 * within the time time source all along. We believe it
1911 * is cleaner and simpler to understand.
1913 if (is_cgroup_event(event))
1914 perf_cgroup_set_shadow_time(event, tstamp);
1916 event->shadow_ctx_time = tstamp - ctx->timestamp;
1919 #define MAX_INTERRUPTS (~0ULL)
1921 static void perf_log_throttle(struct perf_event *event, int enable);
1922 static void perf_log_itrace_start(struct perf_event *event);
1925 event_sched_in(struct perf_event *event,
1926 struct perf_cpu_context *cpuctx,
1927 struct perf_event_context *ctx)
1929 u64 tstamp = perf_event_time(event);
1932 lockdep_assert_held(&ctx->lock);
1934 if (event->state <= PERF_EVENT_STATE_OFF)
1937 event->state = PERF_EVENT_STATE_ACTIVE;
1938 event->oncpu = smp_processor_id();
1941 * Unthrottle events, since we scheduled we might have missed several
1942 * ticks already, also for a heavily scheduling task there is little
1943 * guarantee it'll get a tick in a timely manner.
1945 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1946 perf_log_throttle(event, 1);
1947 event->hw.interrupts = 0;
1951 * The new state must be visible before we turn it on in the hardware:
1955 perf_pmu_disable(event->pmu);
1957 perf_set_shadow_time(event, ctx, tstamp);
1959 perf_log_itrace_start(event);
1961 if (event->pmu->add(event, PERF_EF_START)) {
1962 event->state = PERF_EVENT_STATE_INACTIVE;
1968 event->tstamp_running += tstamp - event->tstamp_stopped;
1970 if (!is_software_event(event))
1971 cpuctx->active_oncpu++;
1972 if (!ctx->nr_active++)
1973 perf_event_ctx_activate(ctx);
1974 if (event->attr.freq && event->attr.sample_freq)
1977 if (event->attr.exclusive)
1978 cpuctx->exclusive = 1;
1980 if (is_orphaned_child(event))
1981 schedule_orphans_remove(ctx);
1984 perf_pmu_enable(event->pmu);
1990 group_sched_in(struct perf_event *group_event,
1991 struct perf_cpu_context *cpuctx,
1992 struct perf_event_context *ctx)
1994 struct perf_event *event, *partial_group = NULL;
1995 struct pmu *pmu = ctx->pmu;
1996 u64 now = ctx->time;
1997 bool simulate = false;
1999 if (group_event->state == PERF_EVENT_STATE_OFF)
2002 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2004 if (event_sched_in(group_event, cpuctx, ctx)) {
2005 pmu->cancel_txn(pmu);
2006 perf_mux_hrtimer_restart(cpuctx);
2011 * Schedule in siblings as one group (if any):
2013 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2014 if (event_sched_in(event, cpuctx, ctx)) {
2015 partial_group = event;
2020 if (!pmu->commit_txn(pmu))
2025 * Groups can be scheduled in as one unit only, so undo any
2026 * partial group before returning:
2027 * The events up to the failed event are scheduled out normally,
2028 * tstamp_stopped will be updated.
2030 * The failed events and the remaining siblings need to have
2031 * their timings updated as if they had gone thru event_sched_in()
2032 * and event_sched_out(). This is required to get consistent timings
2033 * across the group. This also takes care of the case where the group
2034 * could never be scheduled by ensuring tstamp_stopped is set to mark
2035 * the time the event was actually stopped, such that time delta
2036 * calculation in update_event_times() is correct.
2038 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2039 if (event == partial_group)
2043 event->tstamp_running += now - event->tstamp_stopped;
2044 event->tstamp_stopped = now;
2046 event_sched_out(event, cpuctx, ctx);
2049 event_sched_out(group_event, cpuctx, ctx);
2051 pmu->cancel_txn(pmu);
2053 perf_mux_hrtimer_restart(cpuctx);
2059 * Work out whether we can put this event group on the CPU now.
2061 static int group_can_go_on(struct perf_event *event,
2062 struct perf_cpu_context *cpuctx,
2066 * Groups consisting entirely of software events can always go on.
2068 if (event->group_flags & PERF_GROUP_SOFTWARE)
2071 * If an exclusive group is already on, no other hardware
2074 if (cpuctx->exclusive)
2077 * If this group is exclusive and there are already
2078 * events on the CPU, it can't go on.
2080 if (event->attr.exclusive && cpuctx->active_oncpu)
2083 * Otherwise, try to add it if all previous groups were able
2089 static void add_event_to_ctx(struct perf_event *event,
2090 struct perf_event_context *ctx)
2092 u64 tstamp = perf_event_time(event);
2094 list_add_event(event, ctx);
2095 perf_group_attach(event);
2096 event->tstamp_enabled = tstamp;
2097 event->tstamp_running = tstamp;
2098 event->tstamp_stopped = tstamp;
2101 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2102 struct perf_event_context *ctx);
2104 ctx_sched_in(struct perf_event_context *ctx,
2105 struct perf_cpu_context *cpuctx,
2106 enum event_type_t event_type,
2107 struct task_struct *task);
2109 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2110 struct perf_event_context *ctx,
2111 struct task_struct *task)
2113 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2115 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2116 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2118 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2121 static void ctx_resched(struct perf_cpu_context *cpuctx,
2122 struct perf_event_context *task_ctx)
2124 perf_pmu_disable(cpuctx->ctx.pmu);
2126 task_ctx_sched_out(cpuctx, task_ctx);
2127 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2128 perf_event_sched_in(cpuctx, task_ctx, current);
2129 perf_pmu_enable(cpuctx->ctx.pmu);
2133 * Cross CPU call to install and enable a performance event
2135 * Must be called with ctx->mutex held
2137 static int __perf_install_in_context(void *info)
2139 struct perf_event_context *ctx = info;
2140 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2141 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2145 * If we hit the 'wrong' task, we've since scheduled and
2146 * everything should be sorted, nothing to do!
2148 if (ctx->task != current)
2152 * If task_ctx is set, it had better be to us.
2154 WARN_ON_ONCE(cpuctx->task_ctx != ctx && cpuctx->task_ctx);
2158 perf_ctx_lock(cpuctx, task_ctx);
2159 ctx_resched(cpuctx, task_ctx);
2160 perf_ctx_unlock(cpuctx, task_ctx);
2166 * Attach a performance event to a context
2169 perf_install_in_context(struct perf_event_context *ctx,
2170 struct perf_event *event,
2173 struct task_struct *task = NULL;
2175 lockdep_assert_held(&ctx->mutex);
2178 if (event->cpu != -1)
2182 * Installing events is tricky because we cannot rely on ctx->is_active
2183 * to be set in case this is the nr_events 0 -> 1 transition.
2185 * So what we do is we add the event to the list here, which will allow
2186 * a future context switch to DTRT and then send a racy IPI. If the IPI
2187 * fails to hit the right task, this means a context switch must have
2188 * happened and that will have taken care of business.
2190 raw_spin_lock_irq(&ctx->lock);
2191 update_context_time(ctx);
2193 * Update cgrp time only if current cgrp matches event->cgrp.
2194 * Must be done before calling add_event_to_ctx().
2196 update_cgrp_time_from_event(event);
2197 add_event_to_ctx(event, ctx);
2199 raw_spin_unlock_irq(&ctx->lock);
2202 task_function_call(task, __perf_install_in_context, ctx);
2204 cpu_function_call(cpu, __perf_install_in_context, ctx);
2208 * Put a event into inactive state and update time fields.
2209 * Enabling the leader of a group effectively enables all
2210 * the group members that aren't explicitly disabled, so we
2211 * have to update their ->tstamp_enabled also.
2212 * Note: this works for group members as well as group leaders
2213 * since the non-leader members' sibling_lists will be empty.
2215 static void __perf_event_mark_enabled(struct perf_event *event)
2217 struct perf_event *sub;
2218 u64 tstamp = perf_event_time(event);
2220 event->state = PERF_EVENT_STATE_INACTIVE;
2221 event->tstamp_enabled = tstamp - event->total_time_enabled;
2222 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2223 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2224 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2229 * Cross CPU call to enable a performance event
2231 static void __perf_event_enable(struct perf_event *event,
2232 struct perf_cpu_context *cpuctx,
2233 struct perf_event_context *ctx,
2236 struct perf_event *leader = event->group_leader;
2237 struct perf_event_context *task_ctx;
2239 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2242 update_context_time(ctx);
2243 __perf_event_mark_enabled(event);
2245 if (!ctx->is_active)
2248 if (!event_filter_match(event)) {
2249 if (is_cgroup_event(event)) {
2250 perf_cgroup_set_timestamp(current, ctx); // XXX ?
2251 perf_cgroup_defer_enabled(event);
2257 * If the event is in a group and isn't the group leader,
2258 * then don't put it on unless the group is on.
2260 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2263 task_ctx = cpuctx->task_ctx;
2265 WARN_ON_ONCE(task_ctx != ctx);
2267 ctx_resched(cpuctx, task_ctx);
2273 * If event->ctx is a cloned context, callers must make sure that
2274 * every task struct that event->ctx->task could possibly point to
2275 * remains valid. This condition is satisfied when called through
2276 * perf_event_for_each_child or perf_event_for_each as described
2277 * for perf_event_disable.
2279 static void _perf_event_enable(struct perf_event *event)
2281 struct perf_event_context *ctx = event->ctx;
2283 raw_spin_lock_irq(&ctx->lock);
2284 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
2285 raw_spin_unlock_irq(&ctx->lock);
2290 * If the event is in error state, clear that first.
2292 * That way, if we see the event in error state below, we know that it
2293 * has gone back into error state, as distinct from the task having
2294 * been scheduled away before the cross-call arrived.
2296 if (event->state == PERF_EVENT_STATE_ERROR)
2297 event->state = PERF_EVENT_STATE_OFF;
2298 raw_spin_unlock_irq(&ctx->lock);
2300 event_function_call(event, __perf_event_enable, NULL);
2304 * See perf_event_disable();
2306 void perf_event_enable(struct perf_event *event)
2308 struct perf_event_context *ctx;
2310 ctx = perf_event_ctx_lock(event);
2311 _perf_event_enable(event);
2312 perf_event_ctx_unlock(event, ctx);
2314 EXPORT_SYMBOL_GPL(perf_event_enable);
2316 static int _perf_event_refresh(struct perf_event *event, int refresh)
2319 * not supported on inherited events
2321 if (event->attr.inherit || !is_sampling_event(event))
2324 atomic_add(refresh, &event->event_limit);
2325 _perf_event_enable(event);
2331 * See perf_event_disable()
2333 int perf_event_refresh(struct perf_event *event, int refresh)
2335 struct perf_event_context *ctx;
2338 ctx = perf_event_ctx_lock(event);
2339 ret = _perf_event_refresh(event, refresh);
2340 perf_event_ctx_unlock(event, ctx);
2344 EXPORT_SYMBOL_GPL(perf_event_refresh);
2346 static void ctx_sched_out(struct perf_event_context *ctx,
2347 struct perf_cpu_context *cpuctx,
2348 enum event_type_t event_type)
2350 int is_active = ctx->is_active;
2351 struct perf_event *event;
2353 lockdep_assert_held(&ctx->lock);
2355 if (likely(!ctx->nr_events)) {
2357 * See __perf_remove_from_context().
2359 WARN_ON_ONCE(ctx->is_active);
2361 WARN_ON_ONCE(cpuctx->task_ctx);
2365 ctx->is_active &= ~event_type;
2367 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2368 if (!ctx->is_active)
2369 cpuctx->task_ctx = NULL;
2372 update_context_time(ctx);
2373 update_cgrp_time_from_cpuctx(cpuctx);
2374 if (!ctx->nr_active)
2377 perf_pmu_disable(ctx->pmu);
2378 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2379 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2380 group_sched_out(event, cpuctx, ctx);
2383 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2384 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2385 group_sched_out(event, cpuctx, ctx);
2387 perf_pmu_enable(ctx->pmu);
2391 * Test whether two contexts are equivalent, i.e. whether they have both been
2392 * cloned from the same version of the same context.
2394 * Equivalence is measured using a generation number in the context that is
2395 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2396 * and list_del_event().
2398 static int context_equiv(struct perf_event_context *ctx1,
2399 struct perf_event_context *ctx2)
2401 lockdep_assert_held(&ctx1->lock);
2402 lockdep_assert_held(&ctx2->lock);
2404 /* Pinning disables the swap optimization */
2405 if (ctx1->pin_count || ctx2->pin_count)
2408 /* If ctx1 is the parent of ctx2 */
2409 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2412 /* If ctx2 is the parent of ctx1 */
2413 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2417 * If ctx1 and ctx2 have the same parent; we flatten the parent
2418 * hierarchy, see perf_event_init_context().
2420 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2421 ctx1->parent_gen == ctx2->parent_gen)
2428 static void __perf_event_sync_stat(struct perf_event *event,
2429 struct perf_event *next_event)
2433 if (!event->attr.inherit_stat)
2437 * Update the event value, we cannot use perf_event_read()
2438 * because we're in the middle of a context switch and have IRQs
2439 * disabled, which upsets smp_call_function_single(), however
2440 * we know the event must be on the current CPU, therefore we
2441 * don't need to use it.
2443 switch (event->state) {
2444 case PERF_EVENT_STATE_ACTIVE:
2445 event->pmu->read(event);
2448 case PERF_EVENT_STATE_INACTIVE:
2449 update_event_times(event);
2457 * In order to keep per-task stats reliable we need to flip the event
2458 * values when we flip the contexts.
2460 value = local64_read(&next_event->count);
2461 value = local64_xchg(&event->count, value);
2462 local64_set(&next_event->count, value);
2464 swap(event->total_time_enabled, next_event->total_time_enabled);
2465 swap(event->total_time_running, next_event->total_time_running);
2468 * Since we swizzled the values, update the user visible data too.
2470 perf_event_update_userpage(event);
2471 perf_event_update_userpage(next_event);
2474 static void perf_event_sync_stat(struct perf_event_context *ctx,
2475 struct perf_event_context *next_ctx)
2477 struct perf_event *event, *next_event;
2482 update_context_time(ctx);
2484 event = list_first_entry(&ctx->event_list,
2485 struct perf_event, event_entry);
2487 next_event = list_first_entry(&next_ctx->event_list,
2488 struct perf_event, event_entry);
2490 while (&event->event_entry != &ctx->event_list &&
2491 &next_event->event_entry != &next_ctx->event_list) {
2493 __perf_event_sync_stat(event, next_event);
2495 event = list_next_entry(event, event_entry);
2496 next_event = list_next_entry(next_event, event_entry);
2500 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2501 struct task_struct *next)
2503 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2504 struct perf_event_context *next_ctx;
2505 struct perf_event_context *parent, *next_parent;
2506 struct perf_cpu_context *cpuctx;
2512 cpuctx = __get_cpu_context(ctx);
2513 if (!cpuctx->task_ctx)
2517 next_ctx = next->perf_event_ctxp[ctxn];
2521 parent = rcu_dereference(ctx->parent_ctx);
2522 next_parent = rcu_dereference(next_ctx->parent_ctx);
2524 /* If neither context have a parent context; they cannot be clones. */
2525 if (!parent && !next_parent)
2528 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2530 * Looks like the two contexts are clones, so we might be
2531 * able to optimize the context switch. We lock both
2532 * contexts and check that they are clones under the
2533 * lock (including re-checking that neither has been
2534 * uncloned in the meantime). It doesn't matter which
2535 * order we take the locks because no other cpu could
2536 * be trying to lock both of these tasks.
2538 raw_spin_lock(&ctx->lock);
2539 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2540 if (context_equiv(ctx, next_ctx)) {
2542 * XXX do we need a memory barrier of sorts
2543 * wrt to rcu_dereference() of perf_event_ctxp
2545 task->perf_event_ctxp[ctxn] = next_ctx;
2546 next->perf_event_ctxp[ctxn] = ctx;
2548 next_ctx->task = task;
2550 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2554 perf_event_sync_stat(ctx, next_ctx);
2556 raw_spin_unlock(&next_ctx->lock);
2557 raw_spin_unlock(&ctx->lock);
2563 raw_spin_lock(&ctx->lock);
2564 task_ctx_sched_out(cpuctx, ctx);
2565 raw_spin_unlock(&ctx->lock);
2569 void perf_sched_cb_dec(struct pmu *pmu)
2571 this_cpu_dec(perf_sched_cb_usages);
2574 void perf_sched_cb_inc(struct pmu *pmu)
2576 this_cpu_inc(perf_sched_cb_usages);
2580 * This function provides the context switch callback to the lower code
2581 * layer. It is invoked ONLY when the context switch callback is enabled.
2583 static void perf_pmu_sched_task(struct task_struct *prev,
2584 struct task_struct *next,
2587 struct perf_cpu_context *cpuctx;
2589 unsigned long flags;
2594 local_irq_save(flags);
2598 list_for_each_entry_rcu(pmu, &pmus, entry) {
2599 if (pmu->sched_task) {
2600 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2602 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2604 perf_pmu_disable(pmu);
2606 pmu->sched_task(cpuctx->task_ctx, sched_in);
2608 perf_pmu_enable(pmu);
2610 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2616 local_irq_restore(flags);
2619 static void perf_event_switch(struct task_struct *task,
2620 struct task_struct *next_prev, bool sched_in);
2622 #define for_each_task_context_nr(ctxn) \
2623 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2626 * Called from scheduler to remove the events of the current task,
2627 * with interrupts disabled.
2629 * We stop each event and update the event value in event->count.
2631 * This does not protect us against NMI, but disable()
2632 * sets the disabled bit in the control field of event _before_
2633 * accessing the event control register. If a NMI hits, then it will
2634 * not restart the event.
2636 void __perf_event_task_sched_out(struct task_struct *task,
2637 struct task_struct *next)
2641 if (__this_cpu_read(perf_sched_cb_usages))
2642 perf_pmu_sched_task(task, next, false);
2644 if (atomic_read(&nr_switch_events))
2645 perf_event_switch(task, next, false);
2647 for_each_task_context_nr(ctxn)
2648 perf_event_context_sched_out(task, ctxn, next);
2651 * if cgroup events exist on this CPU, then we need
2652 * to check if we have to switch out PMU state.
2653 * cgroup event are system-wide mode only
2655 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2656 perf_cgroup_sched_out(task, next);
2659 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2660 struct perf_event_context *ctx)
2662 if (!cpuctx->task_ctx)
2665 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2668 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2672 * Called with IRQs disabled
2674 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2675 enum event_type_t event_type)
2677 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2681 ctx_pinned_sched_in(struct perf_event_context *ctx,
2682 struct perf_cpu_context *cpuctx)
2684 struct perf_event *event;
2686 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2687 if (event->state <= PERF_EVENT_STATE_OFF)
2689 if (!event_filter_match(event))
2692 /* may need to reset tstamp_enabled */
2693 if (is_cgroup_event(event))
2694 perf_cgroup_mark_enabled(event, ctx);
2696 if (group_can_go_on(event, cpuctx, 1))
2697 group_sched_in(event, cpuctx, ctx);
2700 * If this pinned group hasn't been scheduled,
2701 * put it in error state.
2703 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2704 update_group_times(event);
2705 event->state = PERF_EVENT_STATE_ERROR;
2711 ctx_flexible_sched_in(struct perf_event_context *ctx,
2712 struct perf_cpu_context *cpuctx)
2714 struct perf_event *event;
2717 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2718 /* Ignore events in OFF or ERROR state */
2719 if (event->state <= PERF_EVENT_STATE_OFF)
2722 * Listen to the 'cpu' scheduling filter constraint
2725 if (!event_filter_match(event))
2728 /* may need to reset tstamp_enabled */
2729 if (is_cgroup_event(event))
2730 perf_cgroup_mark_enabled(event, ctx);
2732 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2733 if (group_sched_in(event, cpuctx, ctx))
2740 ctx_sched_in(struct perf_event_context *ctx,
2741 struct perf_cpu_context *cpuctx,
2742 enum event_type_t event_type,
2743 struct task_struct *task)
2745 int is_active = ctx->is_active;
2748 lockdep_assert_held(&ctx->lock);
2750 if (likely(!ctx->nr_events))
2753 ctx->is_active |= event_type;
2756 cpuctx->task_ctx = ctx;
2758 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2762 ctx->timestamp = now;
2763 perf_cgroup_set_timestamp(task, ctx);
2765 * First go through the list and put on any pinned groups
2766 * in order to give them the best chance of going on.
2768 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2769 ctx_pinned_sched_in(ctx, cpuctx);
2771 /* Then walk through the lower prio flexible groups */
2772 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2773 ctx_flexible_sched_in(ctx, cpuctx);
2776 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2777 enum event_type_t event_type,
2778 struct task_struct *task)
2780 struct perf_event_context *ctx = &cpuctx->ctx;
2782 ctx_sched_in(ctx, cpuctx, event_type, task);
2785 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2786 struct task_struct *task)
2788 struct perf_cpu_context *cpuctx;
2790 cpuctx = __get_cpu_context(ctx);
2791 if (cpuctx->task_ctx == ctx)
2794 perf_ctx_lock(cpuctx, ctx);
2795 perf_pmu_disable(ctx->pmu);
2797 * We want to keep the following priority order:
2798 * cpu pinned (that don't need to move), task pinned,
2799 * cpu flexible, task flexible.
2801 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2802 perf_event_sched_in(cpuctx, ctx, task);
2803 perf_pmu_enable(ctx->pmu);
2804 perf_ctx_unlock(cpuctx, ctx);
2808 * Called from scheduler to add the events of the current task
2809 * with interrupts disabled.
2811 * We restore the event value and then enable it.
2813 * This does not protect us against NMI, but enable()
2814 * sets the enabled bit in the control field of event _before_
2815 * accessing the event control register. If a NMI hits, then it will
2816 * keep the event running.
2818 void __perf_event_task_sched_in(struct task_struct *prev,
2819 struct task_struct *task)
2821 struct perf_event_context *ctx;
2825 * If cgroup events exist on this CPU, then we need to check if we have
2826 * to switch in PMU state; cgroup event are system-wide mode only.
2828 * Since cgroup events are CPU events, we must schedule these in before
2829 * we schedule in the task events.
2831 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2832 perf_cgroup_sched_in(prev, task);
2834 for_each_task_context_nr(ctxn) {
2835 ctx = task->perf_event_ctxp[ctxn];
2839 perf_event_context_sched_in(ctx, task);
2842 if (atomic_read(&nr_switch_events))
2843 perf_event_switch(task, prev, true);
2845 if (__this_cpu_read(perf_sched_cb_usages))
2846 perf_pmu_sched_task(prev, task, true);
2849 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2851 u64 frequency = event->attr.sample_freq;
2852 u64 sec = NSEC_PER_SEC;
2853 u64 divisor, dividend;
2855 int count_fls, nsec_fls, frequency_fls, sec_fls;
2857 count_fls = fls64(count);
2858 nsec_fls = fls64(nsec);
2859 frequency_fls = fls64(frequency);
2863 * We got @count in @nsec, with a target of sample_freq HZ
2864 * the target period becomes:
2867 * period = -------------------
2868 * @nsec * sample_freq
2873 * Reduce accuracy by one bit such that @a and @b converge
2874 * to a similar magnitude.
2876 #define REDUCE_FLS(a, b) \
2878 if (a##_fls > b##_fls) { \
2888 * Reduce accuracy until either term fits in a u64, then proceed with
2889 * the other, so that finally we can do a u64/u64 division.
2891 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2892 REDUCE_FLS(nsec, frequency);
2893 REDUCE_FLS(sec, count);
2896 if (count_fls + sec_fls > 64) {
2897 divisor = nsec * frequency;
2899 while (count_fls + sec_fls > 64) {
2900 REDUCE_FLS(count, sec);
2904 dividend = count * sec;
2906 dividend = count * sec;
2908 while (nsec_fls + frequency_fls > 64) {
2909 REDUCE_FLS(nsec, frequency);
2913 divisor = nsec * frequency;
2919 return div64_u64(dividend, divisor);
2922 static DEFINE_PER_CPU(int, perf_throttled_count);
2923 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2925 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2927 struct hw_perf_event *hwc = &event->hw;
2928 s64 period, sample_period;
2931 period = perf_calculate_period(event, nsec, count);
2933 delta = (s64)(period - hwc->sample_period);
2934 delta = (delta + 7) / 8; /* low pass filter */
2936 sample_period = hwc->sample_period + delta;
2941 hwc->sample_period = sample_period;
2943 if (local64_read(&hwc->period_left) > 8*sample_period) {
2945 event->pmu->stop(event, PERF_EF_UPDATE);
2947 local64_set(&hwc->period_left, 0);
2950 event->pmu->start(event, PERF_EF_RELOAD);
2955 * combine freq adjustment with unthrottling to avoid two passes over the
2956 * events. At the same time, make sure, having freq events does not change
2957 * the rate of unthrottling as that would introduce bias.
2959 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2962 struct perf_event *event;
2963 struct hw_perf_event *hwc;
2964 u64 now, period = TICK_NSEC;
2968 * only need to iterate over all events iff:
2969 * - context have events in frequency mode (needs freq adjust)
2970 * - there are events to unthrottle on this cpu
2972 if (!(ctx->nr_freq || needs_unthr))
2975 raw_spin_lock(&ctx->lock);
2976 perf_pmu_disable(ctx->pmu);
2978 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2979 if (event->state != PERF_EVENT_STATE_ACTIVE)
2982 if (!event_filter_match(event))
2985 perf_pmu_disable(event->pmu);
2989 if (hwc->interrupts == MAX_INTERRUPTS) {
2990 hwc->interrupts = 0;
2991 perf_log_throttle(event, 1);
2992 event->pmu->start(event, 0);
2995 if (!event->attr.freq || !event->attr.sample_freq)
2999 * stop the event and update event->count
3001 event->pmu->stop(event, PERF_EF_UPDATE);
3003 now = local64_read(&event->count);
3004 delta = now - hwc->freq_count_stamp;
3005 hwc->freq_count_stamp = now;
3009 * reload only if value has changed
3010 * we have stopped the event so tell that
3011 * to perf_adjust_period() to avoid stopping it
3015 perf_adjust_period(event, period, delta, false);
3017 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3019 perf_pmu_enable(event->pmu);
3022 perf_pmu_enable(ctx->pmu);
3023 raw_spin_unlock(&ctx->lock);
3027 * Round-robin a context's events:
3029 static void rotate_ctx(struct perf_event_context *ctx)
3032 * Rotate the first entry last of non-pinned groups. Rotation might be
3033 * disabled by the inheritance code.
3035 if (!ctx->rotate_disable)
3036 list_rotate_left(&ctx->flexible_groups);
3039 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3041 struct perf_event_context *ctx = NULL;
3044 if (cpuctx->ctx.nr_events) {
3045 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3049 ctx = cpuctx->task_ctx;
3050 if (ctx && ctx->nr_events) {
3051 if (ctx->nr_events != ctx->nr_active)
3058 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3059 perf_pmu_disable(cpuctx->ctx.pmu);
3061 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3063 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3065 rotate_ctx(&cpuctx->ctx);
3069 perf_event_sched_in(cpuctx, ctx, current);
3071 perf_pmu_enable(cpuctx->ctx.pmu);
3072 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3078 #ifdef CONFIG_NO_HZ_FULL
3079 bool perf_event_can_stop_tick(void)
3081 if (atomic_read(&nr_freq_events) ||
3082 __this_cpu_read(perf_throttled_count))
3089 void perf_event_task_tick(void)
3091 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3092 struct perf_event_context *ctx, *tmp;
3095 WARN_ON(!irqs_disabled());
3097 __this_cpu_inc(perf_throttled_seq);
3098 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3100 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3101 perf_adjust_freq_unthr_context(ctx, throttled);
3104 static int event_enable_on_exec(struct perf_event *event,
3105 struct perf_event_context *ctx)
3107 if (!event->attr.enable_on_exec)
3110 event->attr.enable_on_exec = 0;
3111 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3114 __perf_event_mark_enabled(event);
3120 * Enable all of a task's events that have been marked enable-on-exec.
3121 * This expects task == current.
3123 static void perf_event_enable_on_exec(int ctxn)
3125 struct perf_event_context *ctx, *clone_ctx = NULL;
3126 struct perf_cpu_context *cpuctx;
3127 struct perf_event *event;
3128 unsigned long flags;
3131 local_irq_save(flags);
3132 ctx = current->perf_event_ctxp[ctxn];
3133 if (!ctx || !ctx->nr_events)
3136 cpuctx = __get_cpu_context(ctx);
3137 perf_ctx_lock(cpuctx, ctx);
3138 list_for_each_entry(event, &ctx->event_list, event_entry)
3139 enabled |= event_enable_on_exec(event, ctx);
3142 * Unclone and reschedule this context if we enabled any event.
3145 clone_ctx = unclone_ctx(ctx);
3146 ctx_resched(cpuctx, ctx);
3148 perf_ctx_unlock(cpuctx, ctx);
3151 local_irq_restore(flags);
3157 void perf_event_exec(void)
3162 for_each_task_context_nr(ctxn)
3163 perf_event_enable_on_exec(ctxn);
3167 struct perf_read_data {
3168 struct perf_event *event;
3174 * Cross CPU call to read the hardware event
3176 static void __perf_event_read(void *info)
3178 struct perf_read_data *data = info;
3179 struct perf_event *sub, *event = data->event;
3180 struct perf_event_context *ctx = event->ctx;
3181 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3182 struct pmu *pmu = event->pmu;
3185 * If this is a task context, we need to check whether it is
3186 * the current task context of this cpu. If not it has been
3187 * scheduled out before the smp call arrived. In that case
3188 * event->count would have been updated to a recent sample
3189 * when the event was scheduled out.
3191 if (ctx->task && cpuctx->task_ctx != ctx)
3194 raw_spin_lock(&ctx->lock);
3195 if (ctx->is_active) {
3196 update_context_time(ctx);
3197 update_cgrp_time_from_event(event);
3200 update_event_times(event);
3201 if (event->state != PERF_EVENT_STATE_ACTIVE)
3210 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3214 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3215 update_event_times(sub);
3216 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3218 * Use sibling's PMU rather than @event's since
3219 * sibling could be on different (eg: software) PMU.
3221 sub->pmu->read(sub);
3225 data->ret = pmu->commit_txn(pmu);
3228 raw_spin_unlock(&ctx->lock);
3231 static inline u64 perf_event_count(struct perf_event *event)
3233 if (event->pmu->count)
3234 return event->pmu->count(event);
3236 return __perf_event_count(event);
3240 * NMI-safe method to read a local event, that is an event that
3242 * - either for the current task, or for this CPU
3243 * - does not have inherit set, for inherited task events
3244 * will not be local and we cannot read them atomically
3245 * - must not have a pmu::count method
3247 u64 perf_event_read_local(struct perf_event *event)
3249 unsigned long flags;
3253 * Disabling interrupts avoids all counter scheduling (context
3254 * switches, timer based rotation and IPIs).
3256 local_irq_save(flags);
3258 /* If this is a per-task event, it must be for current */
3259 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3260 event->hw.target != current);
3262 /* If this is a per-CPU event, it must be for this CPU */
3263 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3264 event->cpu != smp_processor_id());
3267 * It must not be an event with inherit set, we cannot read
3268 * all child counters from atomic context.
3270 WARN_ON_ONCE(event->attr.inherit);
3273 * It must not have a pmu::count method, those are not
3276 WARN_ON_ONCE(event->pmu->count);
3279 * If the event is currently on this CPU, its either a per-task event,
3280 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3283 if (event->oncpu == smp_processor_id())
3284 event->pmu->read(event);
3286 val = local64_read(&event->count);
3287 local_irq_restore(flags);
3292 static int perf_event_read(struct perf_event *event, bool group)
3297 * If event is enabled and currently active on a CPU, update the
3298 * value in the event structure:
3300 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3301 struct perf_read_data data = {
3306 smp_call_function_single(event->oncpu,
3307 __perf_event_read, &data, 1);
3309 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3310 struct perf_event_context *ctx = event->ctx;
3311 unsigned long flags;
3313 raw_spin_lock_irqsave(&ctx->lock, flags);
3315 * may read while context is not active
3316 * (e.g., thread is blocked), in that case
3317 * we cannot update context time
3319 if (ctx->is_active) {
3320 update_context_time(ctx);
3321 update_cgrp_time_from_event(event);
3324 update_group_times(event);
3326 update_event_times(event);
3327 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3334 * Initialize the perf_event context in a task_struct:
3336 static void __perf_event_init_context(struct perf_event_context *ctx)
3338 raw_spin_lock_init(&ctx->lock);
3339 mutex_init(&ctx->mutex);
3340 INIT_LIST_HEAD(&ctx->active_ctx_list);
3341 INIT_LIST_HEAD(&ctx->pinned_groups);
3342 INIT_LIST_HEAD(&ctx->flexible_groups);
3343 INIT_LIST_HEAD(&ctx->event_list);
3344 atomic_set(&ctx->refcount, 1);
3345 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3348 static struct perf_event_context *
3349 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3351 struct perf_event_context *ctx;
3353 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3357 __perf_event_init_context(ctx);
3360 get_task_struct(task);
3367 static struct task_struct *
3368 find_lively_task_by_vpid(pid_t vpid)
3370 struct task_struct *task;
3377 task = find_task_by_vpid(vpid);
3379 get_task_struct(task);
3383 return ERR_PTR(-ESRCH);
3385 /* Reuse ptrace permission checks for now. */
3387 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3392 put_task_struct(task);
3393 return ERR_PTR(err);
3398 * Returns a matching context with refcount and pincount.
3400 static struct perf_event_context *
3401 find_get_context(struct pmu *pmu, struct task_struct *task,
3402 struct perf_event *event)
3404 struct perf_event_context *ctx, *clone_ctx = NULL;
3405 struct perf_cpu_context *cpuctx;
3406 void *task_ctx_data = NULL;
3407 unsigned long flags;
3409 int cpu = event->cpu;
3412 /* Must be root to operate on a CPU event: */
3413 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3414 return ERR_PTR(-EACCES);
3417 * We could be clever and allow to attach a event to an
3418 * offline CPU and activate it when the CPU comes up, but
3421 if (!cpu_online(cpu))
3422 return ERR_PTR(-ENODEV);
3424 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3433 ctxn = pmu->task_ctx_nr;
3437 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3438 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3439 if (!task_ctx_data) {
3446 ctx = perf_lock_task_context(task, ctxn, &flags);
3448 clone_ctx = unclone_ctx(ctx);
3451 if (task_ctx_data && !ctx->task_ctx_data) {
3452 ctx->task_ctx_data = task_ctx_data;
3453 task_ctx_data = NULL;
3455 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3460 ctx = alloc_perf_context(pmu, task);
3465 if (task_ctx_data) {
3466 ctx->task_ctx_data = task_ctx_data;
3467 task_ctx_data = NULL;
3471 mutex_lock(&task->perf_event_mutex);
3473 * If it has already passed perf_event_exit_task().
3474 * we must see PF_EXITING, it takes this mutex too.
3476 if (task->flags & PF_EXITING)
3478 else if (task->perf_event_ctxp[ctxn])
3483 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3485 mutex_unlock(&task->perf_event_mutex);
3487 if (unlikely(err)) {
3496 kfree(task_ctx_data);
3500 kfree(task_ctx_data);
3501 return ERR_PTR(err);
3504 static void perf_event_free_filter(struct perf_event *event);
3505 static void perf_event_free_bpf_prog(struct perf_event *event);
3507 static void free_event_rcu(struct rcu_head *head)
3509 struct perf_event *event;
3511 event = container_of(head, struct perf_event, rcu_head);
3513 put_pid_ns(event->ns);
3514 perf_event_free_filter(event);
3518 static void ring_buffer_attach(struct perf_event *event,
3519 struct ring_buffer *rb);
3521 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3526 if (is_cgroup_event(event))
3527 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3530 static void unaccount_event(struct perf_event *event)
3537 if (event->attach_state & PERF_ATTACH_TASK)
3539 if (event->attr.mmap || event->attr.mmap_data)
3540 atomic_dec(&nr_mmap_events);
3541 if (event->attr.comm)
3542 atomic_dec(&nr_comm_events);
3543 if (event->attr.task)
3544 atomic_dec(&nr_task_events);
3545 if (event->attr.freq)
3546 atomic_dec(&nr_freq_events);
3547 if (event->attr.context_switch) {
3549 atomic_dec(&nr_switch_events);
3551 if (is_cgroup_event(event))
3553 if (has_branch_stack(event))
3557 static_key_slow_dec_deferred(&perf_sched_events);
3559 unaccount_event_cpu(event, event->cpu);
3563 * The following implement mutual exclusion of events on "exclusive" pmus
3564 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3565 * at a time, so we disallow creating events that might conflict, namely:
3567 * 1) cpu-wide events in the presence of per-task events,
3568 * 2) per-task events in the presence of cpu-wide events,
3569 * 3) two matching events on the same context.
3571 * The former two cases are handled in the allocation path (perf_event_alloc(),
3572 * __free_event()), the latter -- before the first perf_install_in_context().
3574 static int exclusive_event_init(struct perf_event *event)
3576 struct pmu *pmu = event->pmu;
3578 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3582 * Prevent co-existence of per-task and cpu-wide events on the
3583 * same exclusive pmu.
3585 * Negative pmu::exclusive_cnt means there are cpu-wide
3586 * events on this "exclusive" pmu, positive means there are
3589 * Since this is called in perf_event_alloc() path, event::ctx
3590 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3591 * to mean "per-task event", because unlike other attach states it
3592 * never gets cleared.
3594 if (event->attach_state & PERF_ATTACH_TASK) {
3595 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3598 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3605 static void exclusive_event_destroy(struct perf_event *event)
3607 struct pmu *pmu = event->pmu;
3609 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3612 /* see comment in exclusive_event_init() */
3613 if (event->attach_state & PERF_ATTACH_TASK)
3614 atomic_dec(&pmu->exclusive_cnt);
3616 atomic_inc(&pmu->exclusive_cnt);
3619 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3621 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3622 (e1->cpu == e2->cpu ||
3629 /* Called under the same ctx::mutex as perf_install_in_context() */
3630 static bool exclusive_event_installable(struct perf_event *event,
3631 struct perf_event_context *ctx)
3633 struct perf_event *iter_event;
3634 struct pmu *pmu = event->pmu;
3636 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3639 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3640 if (exclusive_event_match(iter_event, event))
3647 static void __free_event(struct perf_event *event)
3649 if (!event->parent) {
3650 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3651 put_callchain_buffers();
3654 perf_event_free_bpf_prog(event);
3657 event->destroy(event);
3660 put_ctx(event->ctx);
3663 exclusive_event_destroy(event);
3664 module_put(event->pmu->module);
3667 call_rcu(&event->rcu_head, free_event_rcu);
3670 static void _free_event(struct perf_event *event)
3672 irq_work_sync(&event->pending);
3674 unaccount_event(event);
3678 * Can happen when we close an event with re-directed output.
3680 * Since we have a 0 refcount, perf_mmap_close() will skip
3681 * over us; possibly making our ring_buffer_put() the last.
3683 mutex_lock(&event->mmap_mutex);
3684 ring_buffer_attach(event, NULL);
3685 mutex_unlock(&event->mmap_mutex);
3688 if (is_cgroup_event(event))
3689 perf_detach_cgroup(event);
3691 __free_event(event);
3695 * Used to free events which have a known refcount of 1, such as in error paths
3696 * where the event isn't exposed yet and inherited events.
3698 static void free_event(struct perf_event *event)
3700 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3701 "unexpected event refcount: %ld; ptr=%p\n",
3702 atomic_long_read(&event->refcount), event)) {
3703 /* leak to avoid use-after-free */
3711 * Remove user event from the owner task.
3713 static void perf_remove_from_owner(struct perf_event *event)
3715 struct task_struct *owner;
3718 owner = ACCESS_ONCE(event->owner);
3720 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3721 * !owner it means the list deletion is complete and we can indeed
3722 * free this event, otherwise we need to serialize on
3723 * owner->perf_event_mutex.
3725 smp_read_barrier_depends();
3728 * Since delayed_put_task_struct() also drops the last
3729 * task reference we can safely take a new reference
3730 * while holding the rcu_read_lock().
3732 get_task_struct(owner);
3738 * If we're here through perf_event_exit_task() we're already
3739 * holding ctx->mutex which would be an inversion wrt. the
3740 * normal lock order.
3742 * However we can safely take this lock because its the child
3745 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3748 * We have to re-check the event->owner field, if it is cleared
3749 * we raced with perf_event_exit_task(), acquiring the mutex
3750 * ensured they're done, and we can proceed with freeing the
3754 list_del_init(&event->owner_entry);
3755 mutex_unlock(&owner->perf_event_mutex);
3756 put_task_struct(owner);
3760 static void put_event(struct perf_event *event)
3762 struct perf_event_context *ctx;
3764 if (!atomic_long_dec_and_test(&event->refcount))
3767 if (!is_kernel_event(event))
3768 perf_remove_from_owner(event);
3771 * There are two ways this annotation is useful:
3773 * 1) there is a lock recursion from perf_event_exit_task
3774 * see the comment there.
3776 * 2) there is a lock-inversion with mmap_sem through
3777 * perf_read_group(), which takes faults while
3778 * holding ctx->mutex, however this is called after
3779 * the last filedesc died, so there is no possibility
3780 * to trigger the AB-BA case.
3782 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3783 WARN_ON_ONCE(ctx->parent_ctx);
3784 perf_remove_from_context(event, true);
3785 perf_event_ctx_unlock(event, ctx);
3790 int perf_event_release_kernel(struct perf_event *event)
3795 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3798 * Called when the last reference to the file is gone.
3800 static int perf_release(struct inode *inode, struct file *file)
3802 put_event(file->private_data);
3807 * Remove all orphanes events from the context.
3809 static void orphans_remove_work(struct work_struct *work)
3811 struct perf_event_context *ctx;
3812 struct perf_event *event, *tmp;
3814 ctx = container_of(work, struct perf_event_context,
3815 orphans_remove.work);
3817 mutex_lock(&ctx->mutex);
3818 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3819 struct perf_event *parent_event = event->parent;
3821 if (!is_orphaned_child(event))
3824 perf_remove_from_context(event, true);
3826 mutex_lock(&parent_event->child_mutex);
3827 list_del_init(&event->child_list);
3828 mutex_unlock(&parent_event->child_mutex);
3831 put_event(parent_event);
3834 raw_spin_lock_irq(&ctx->lock);
3835 ctx->orphans_remove_sched = false;
3836 raw_spin_unlock_irq(&ctx->lock);
3837 mutex_unlock(&ctx->mutex);
3842 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3844 struct perf_event *child;
3850 mutex_lock(&event->child_mutex);
3852 (void)perf_event_read(event, false);
3853 total += perf_event_count(event);
3855 *enabled += event->total_time_enabled +
3856 atomic64_read(&event->child_total_time_enabled);
3857 *running += event->total_time_running +
3858 atomic64_read(&event->child_total_time_running);
3860 list_for_each_entry(child, &event->child_list, child_list) {
3861 (void)perf_event_read(child, false);
3862 total += perf_event_count(child);
3863 *enabled += child->total_time_enabled;
3864 *running += child->total_time_running;
3866 mutex_unlock(&event->child_mutex);
3870 EXPORT_SYMBOL_GPL(perf_event_read_value);
3872 static int __perf_read_group_add(struct perf_event *leader,
3873 u64 read_format, u64 *values)
3875 struct perf_event *sub;
3876 int n = 1; /* skip @nr */
3879 ret = perf_event_read(leader, true);
3884 * Since we co-schedule groups, {enabled,running} times of siblings
3885 * will be identical to those of the leader, so we only publish one
3888 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3889 values[n++] += leader->total_time_enabled +
3890 atomic64_read(&leader->child_total_time_enabled);
3893 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3894 values[n++] += leader->total_time_running +
3895 atomic64_read(&leader->child_total_time_running);
3899 * Write {count,id} tuples for every sibling.
3901 values[n++] += perf_event_count(leader);
3902 if (read_format & PERF_FORMAT_ID)
3903 values[n++] = primary_event_id(leader);
3905 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3906 values[n++] += perf_event_count(sub);
3907 if (read_format & PERF_FORMAT_ID)
3908 values[n++] = primary_event_id(sub);
3914 static int perf_read_group(struct perf_event *event,
3915 u64 read_format, char __user *buf)
3917 struct perf_event *leader = event->group_leader, *child;
3918 struct perf_event_context *ctx = leader->ctx;
3922 lockdep_assert_held(&ctx->mutex);
3924 values = kzalloc(event->read_size, GFP_KERNEL);
3928 values[0] = 1 + leader->nr_siblings;
3931 * By locking the child_mutex of the leader we effectively
3932 * lock the child list of all siblings.. XXX explain how.
3934 mutex_lock(&leader->child_mutex);
3936 ret = __perf_read_group_add(leader, read_format, values);
3940 list_for_each_entry(child, &leader->child_list, child_list) {
3941 ret = __perf_read_group_add(child, read_format, values);
3946 mutex_unlock(&leader->child_mutex);
3948 ret = event->read_size;
3949 if (copy_to_user(buf, values, event->read_size))
3954 mutex_unlock(&leader->child_mutex);
3960 static int perf_read_one(struct perf_event *event,
3961 u64 read_format, char __user *buf)
3963 u64 enabled, running;
3967 values[n++] = perf_event_read_value(event, &enabled, &running);
3968 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3969 values[n++] = enabled;
3970 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3971 values[n++] = running;
3972 if (read_format & PERF_FORMAT_ID)
3973 values[n++] = primary_event_id(event);
3975 if (copy_to_user(buf, values, n * sizeof(u64)))
3978 return n * sizeof(u64);
3981 static bool is_event_hup(struct perf_event *event)
3985 if (event->state != PERF_EVENT_STATE_EXIT)
3988 mutex_lock(&event->child_mutex);
3989 no_children = list_empty(&event->child_list);
3990 mutex_unlock(&event->child_mutex);
3995 * Read the performance event - simple non blocking version for now
3998 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4000 u64 read_format = event->attr.read_format;
4004 * Return end-of-file for a read on a event that is in
4005 * error state (i.e. because it was pinned but it couldn't be
4006 * scheduled on to the CPU at some point).
4008 if (event->state == PERF_EVENT_STATE_ERROR)
4011 if (count < event->read_size)
4014 WARN_ON_ONCE(event->ctx->parent_ctx);
4015 if (read_format & PERF_FORMAT_GROUP)
4016 ret = perf_read_group(event, read_format, buf);
4018 ret = perf_read_one(event, read_format, buf);
4024 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4026 struct perf_event *event = file->private_data;
4027 struct perf_event_context *ctx;
4030 ctx = perf_event_ctx_lock(event);
4031 ret = __perf_read(event, buf, count);
4032 perf_event_ctx_unlock(event, ctx);
4037 static unsigned int perf_poll(struct file *file, poll_table *wait)
4039 struct perf_event *event = file->private_data;
4040 struct ring_buffer *rb;
4041 unsigned int events = POLLHUP;
4043 poll_wait(file, &event->waitq, wait);
4045 if (is_event_hup(event))
4049 * Pin the event->rb by taking event->mmap_mutex; otherwise
4050 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4052 mutex_lock(&event->mmap_mutex);
4055 events = atomic_xchg(&rb->poll, 0);
4056 mutex_unlock(&event->mmap_mutex);
4060 static void _perf_event_reset(struct perf_event *event)
4062 (void)perf_event_read(event, false);
4063 local64_set(&event->count, 0);
4064 perf_event_update_userpage(event);
4068 * Holding the top-level event's child_mutex means that any
4069 * descendant process that has inherited this event will block
4070 * in sync_child_event if it goes to exit, thus satisfying the
4071 * task existence requirements of perf_event_enable/disable.
4073 static void perf_event_for_each_child(struct perf_event *event,
4074 void (*func)(struct perf_event *))
4076 struct perf_event *child;
4078 WARN_ON_ONCE(event->ctx->parent_ctx);
4080 mutex_lock(&event->child_mutex);
4082 list_for_each_entry(child, &event->child_list, child_list)
4084 mutex_unlock(&event->child_mutex);
4087 static void perf_event_for_each(struct perf_event *event,
4088 void (*func)(struct perf_event *))
4090 struct perf_event_context *ctx = event->ctx;
4091 struct perf_event *sibling;
4093 lockdep_assert_held(&ctx->mutex);
4095 event = event->group_leader;
4097 perf_event_for_each_child(event, func);
4098 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4099 perf_event_for_each_child(sibling, func);
4102 static void __perf_event_period(struct perf_event *event,
4103 struct perf_cpu_context *cpuctx,
4104 struct perf_event_context *ctx,
4107 u64 value = *((u64 *)info);
4110 if (event->attr.freq) {
4111 event->attr.sample_freq = value;
4113 event->attr.sample_period = value;
4114 event->hw.sample_period = value;
4117 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4119 perf_pmu_disable(ctx->pmu);
4120 event->pmu->stop(event, PERF_EF_UPDATE);
4123 local64_set(&event->hw.period_left, 0);
4126 event->pmu->start(event, PERF_EF_RELOAD);
4127 perf_pmu_enable(ctx->pmu);
4131 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4135 if (!is_sampling_event(event))
4138 if (copy_from_user(&value, arg, sizeof(value)))
4144 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4147 event_function_call(event, __perf_event_period, &value);
4152 static const struct file_operations perf_fops;
4154 static inline int perf_fget_light(int fd, struct fd *p)
4156 struct fd f = fdget(fd);
4160 if (f.file->f_op != &perf_fops) {
4168 static int perf_event_set_output(struct perf_event *event,
4169 struct perf_event *output_event);
4170 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4171 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4173 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4175 void (*func)(struct perf_event *);
4179 case PERF_EVENT_IOC_ENABLE:
4180 func = _perf_event_enable;
4182 case PERF_EVENT_IOC_DISABLE:
4183 func = _perf_event_disable;
4185 case PERF_EVENT_IOC_RESET:
4186 func = _perf_event_reset;
4189 case PERF_EVENT_IOC_REFRESH:
4190 return _perf_event_refresh(event, arg);
4192 case PERF_EVENT_IOC_PERIOD:
4193 return perf_event_period(event, (u64 __user *)arg);
4195 case PERF_EVENT_IOC_ID:
4197 u64 id = primary_event_id(event);
4199 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4204 case PERF_EVENT_IOC_SET_OUTPUT:
4208 struct perf_event *output_event;
4210 ret = perf_fget_light(arg, &output);
4213 output_event = output.file->private_data;
4214 ret = perf_event_set_output(event, output_event);
4217 ret = perf_event_set_output(event, NULL);
4222 case PERF_EVENT_IOC_SET_FILTER:
4223 return perf_event_set_filter(event, (void __user *)arg);
4225 case PERF_EVENT_IOC_SET_BPF:
4226 return perf_event_set_bpf_prog(event, arg);
4232 if (flags & PERF_IOC_FLAG_GROUP)
4233 perf_event_for_each(event, func);
4235 perf_event_for_each_child(event, func);
4240 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4242 struct perf_event *event = file->private_data;
4243 struct perf_event_context *ctx;
4246 ctx = perf_event_ctx_lock(event);
4247 ret = _perf_ioctl(event, cmd, arg);
4248 perf_event_ctx_unlock(event, ctx);
4253 #ifdef CONFIG_COMPAT
4254 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4257 switch (_IOC_NR(cmd)) {
4258 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4259 case _IOC_NR(PERF_EVENT_IOC_ID):
4260 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4261 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4262 cmd &= ~IOCSIZE_MASK;
4263 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4267 return perf_ioctl(file, cmd, arg);
4270 # define perf_compat_ioctl NULL
4273 int perf_event_task_enable(void)
4275 struct perf_event_context *ctx;
4276 struct perf_event *event;
4278 mutex_lock(¤t->perf_event_mutex);
4279 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4280 ctx = perf_event_ctx_lock(event);
4281 perf_event_for_each_child(event, _perf_event_enable);
4282 perf_event_ctx_unlock(event, ctx);
4284 mutex_unlock(¤t->perf_event_mutex);
4289 int perf_event_task_disable(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_disable);
4298 perf_event_ctx_unlock(event, ctx);
4300 mutex_unlock(¤t->perf_event_mutex);
4305 static int perf_event_index(struct perf_event *event)
4307 if (event->hw.state & PERF_HES_STOPPED)
4310 if (event->state != PERF_EVENT_STATE_ACTIVE)
4313 return event->pmu->event_idx(event);
4316 static void calc_timer_values(struct perf_event *event,
4323 *now = perf_clock();
4324 ctx_time = event->shadow_ctx_time + *now;
4325 *enabled = ctx_time - event->tstamp_enabled;
4326 *running = ctx_time - event->tstamp_running;
4329 static void perf_event_init_userpage(struct perf_event *event)
4331 struct perf_event_mmap_page *userpg;
4332 struct ring_buffer *rb;
4335 rb = rcu_dereference(event->rb);
4339 userpg = rb->user_page;
4341 /* Allow new userspace to detect that bit 0 is deprecated */
4342 userpg->cap_bit0_is_deprecated = 1;
4343 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4344 userpg->data_offset = PAGE_SIZE;
4345 userpg->data_size = perf_data_size(rb);
4351 void __weak arch_perf_update_userpage(
4352 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4357 * Callers need to ensure there can be no nesting of this function, otherwise
4358 * the seqlock logic goes bad. We can not serialize this because the arch
4359 * code calls this from NMI context.
4361 void perf_event_update_userpage(struct perf_event *event)
4363 struct perf_event_mmap_page *userpg;
4364 struct ring_buffer *rb;
4365 u64 enabled, running, now;
4368 rb = rcu_dereference(event->rb);
4373 * compute total_time_enabled, total_time_running
4374 * based on snapshot values taken when the event
4375 * was last scheduled in.
4377 * we cannot simply called update_context_time()
4378 * because of locking issue as we can be called in
4381 calc_timer_values(event, &now, &enabled, &running);
4383 userpg = rb->user_page;
4385 * Disable preemption so as to not let the corresponding user-space
4386 * spin too long if we get preempted.
4391 userpg->index = perf_event_index(event);
4392 userpg->offset = perf_event_count(event);
4394 userpg->offset -= local64_read(&event->hw.prev_count);
4396 userpg->time_enabled = enabled +
4397 atomic64_read(&event->child_total_time_enabled);
4399 userpg->time_running = running +
4400 atomic64_read(&event->child_total_time_running);
4402 arch_perf_update_userpage(event, userpg, now);
4411 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4413 struct perf_event *event = vma->vm_file->private_data;
4414 struct ring_buffer *rb;
4415 int ret = VM_FAULT_SIGBUS;
4417 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4418 if (vmf->pgoff == 0)
4424 rb = rcu_dereference(event->rb);
4428 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4431 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4435 get_page(vmf->page);
4436 vmf->page->mapping = vma->vm_file->f_mapping;
4437 vmf->page->index = vmf->pgoff;
4446 static void ring_buffer_attach(struct perf_event *event,
4447 struct ring_buffer *rb)
4449 struct ring_buffer *old_rb = NULL;
4450 unsigned long flags;
4454 * Should be impossible, we set this when removing
4455 * event->rb_entry and wait/clear when adding event->rb_entry.
4457 WARN_ON_ONCE(event->rcu_pending);
4460 spin_lock_irqsave(&old_rb->event_lock, flags);
4461 list_del_rcu(&event->rb_entry);
4462 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4464 event->rcu_batches = get_state_synchronize_rcu();
4465 event->rcu_pending = 1;
4469 if (event->rcu_pending) {
4470 cond_synchronize_rcu(event->rcu_batches);
4471 event->rcu_pending = 0;
4474 spin_lock_irqsave(&rb->event_lock, flags);
4475 list_add_rcu(&event->rb_entry, &rb->event_list);
4476 spin_unlock_irqrestore(&rb->event_lock, flags);
4479 rcu_assign_pointer(event->rb, rb);
4482 ring_buffer_put(old_rb);
4484 * Since we detached before setting the new rb, so that we
4485 * could attach the new rb, we could have missed a wakeup.
4488 wake_up_all(&event->waitq);
4492 static void ring_buffer_wakeup(struct perf_event *event)
4494 struct ring_buffer *rb;
4497 rb = rcu_dereference(event->rb);
4499 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4500 wake_up_all(&event->waitq);
4505 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4507 struct ring_buffer *rb;
4510 rb = rcu_dereference(event->rb);
4512 if (!atomic_inc_not_zero(&rb->refcount))
4520 void ring_buffer_put(struct ring_buffer *rb)
4522 if (!atomic_dec_and_test(&rb->refcount))
4525 WARN_ON_ONCE(!list_empty(&rb->event_list));
4527 call_rcu(&rb->rcu_head, rb_free_rcu);
4530 static void perf_mmap_open(struct vm_area_struct *vma)
4532 struct perf_event *event = vma->vm_file->private_data;
4534 atomic_inc(&event->mmap_count);
4535 atomic_inc(&event->rb->mmap_count);
4538 atomic_inc(&event->rb->aux_mmap_count);
4540 if (event->pmu->event_mapped)
4541 event->pmu->event_mapped(event);
4545 * A buffer can be mmap()ed multiple times; either directly through the same
4546 * event, or through other events by use of perf_event_set_output().
4548 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4549 * the buffer here, where we still have a VM context. This means we need
4550 * to detach all events redirecting to us.
4552 static void perf_mmap_close(struct vm_area_struct *vma)
4554 struct perf_event *event = vma->vm_file->private_data;
4556 struct ring_buffer *rb = ring_buffer_get(event);
4557 struct user_struct *mmap_user = rb->mmap_user;
4558 int mmap_locked = rb->mmap_locked;
4559 unsigned long size = perf_data_size(rb);
4561 if (event->pmu->event_unmapped)
4562 event->pmu->event_unmapped(event);
4565 * rb->aux_mmap_count will always drop before rb->mmap_count and
4566 * event->mmap_count, so it is ok to use event->mmap_mutex to
4567 * serialize with perf_mmap here.
4569 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4570 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4571 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4572 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4575 mutex_unlock(&event->mmap_mutex);
4578 atomic_dec(&rb->mmap_count);
4580 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4583 ring_buffer_attach(event, NULL);
4584 mutex_unlock(&event->mmap_mutex);
4586 /* If there's still other mmap()s of this buffer, we're done. */
4587 if (atomic_read(&rb->mmap_count))
4591 * No other mmap()s, detach from all other events that might redirect
4592 * into the now unreachable buffer. Somewhat complicated by the
4593 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4597 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4598 if (!atomic_long_inc_not_zero(&event->refcount)) {
4600 * This event is en-route to free_event() which will
4601 * detach it and remove it from the list.
4607 mutex_lock(&event->mmap_mutex);
4609 * Check we didn't race with perf_event_set_output() which can
4610 * swizzle the rb from under us while we were waiting to
4611 * acquire mmap_mutex.
4613 * If we find a different rb; ignore this event, a next
4614 * iteration will no longer find it on the list. We have to
4615 * still restart the iteration to make sure we're not now
4616 * iterating the wrong list.
4618 if (event->rb == rb)
4619 ring_buffer_attach(event, NULL);
4621 mutex_unlock(&event->mmap_mutex);
4625 * Restart the iteration; either we're on the wrong list or
4626 * destroyed its integrity by doing a deletion.
4633 * It could be there's still a few 0-ref events on the list; they'll
4634 * get cleaned up by free_event() -- they'll also still have their
4635 * ref on the rb and will free it whenever they are done with it.
4637 * Aside from that, this buffer is 'fully' detached and unmapped,
4638 * undo the VM accounting.
4641 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4642 vma->vm_mm->pinned_vm -= mmap_locked;
4643 free_uid(mmap_user);
4646 ring_buffer_put(rb); /* could be last */
4649 static const struct vm_operations_struct perf_mmap_vmops = {
4650 .open = perf_mmap_open,
4651 .close = perf_mmap_close, /* non mergable */
4652 .fault = perf_mmap_fault,
4653 .page_mkwrite = perf_mmap_fault,
4656 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4658 struct perf_event *event = file->private_data;
4659 unsigned long user_locked, user_lock_limit;
4660 struct user_struct *user = current_user();
4661 unsigned long locked, lock_limit;
4662 struct ring_buffer *rb = NULL;
4663 unsigned long vma_size;
4664 unsigned long nr_pages;
4665 long user_extra = 0, extra = 0;
4666 int ret = 0, flags = 0;
4669 * Don't allow mmap() of inherited per-task counters. This would
4670 * create a performance issue due to all children writing to the
4673 if (event->cpu == -1 && event->attr.inherit)
4676 if (!(vma->vm_flags & VM_SHARED))
4679 vma_size = vma->vm_end - vma->vm_start;
4681 if (vma->vm_pgoff == 0) {
4682 nr_pages = (vma_size / PAGE_SIZE) - 1;
4685 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4686 * mapped, all subsequent mappings should have the same size
4687 * and offset. Must be above the normal perf buffer.
4689 u64 aux_offset, aux_size;
4694 nr_pages = vma_size / PAGE_SIZE;
4696 mutex_lock(&event->mmap_mutex);
4703 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4704 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4706 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4709 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4712 /* already mapped with a different offset */
4713 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4716 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4719 /* already mapped with a different size */
4720 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4723 if (!is_power_of_2(nr_pages))
4726 if (!atomic_inc_not_zero(&rb->mmap_count))
4729 if (rb_has_aux(rb)) {
4730 atomic_inc(&rb->aux_mmap_count);
4735 atomic_set(&rb->aux_mmap_count, 1);
4736 user_extra = nr_pages;
4742 * If we have rb pages ensure they're a power-of-two number, so we
4743 * can do bitmasks instead of modulo.
4745 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4748 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4751 WARN_ON_ONCE(event->ctx->parent_ctx);
4753 mutex_lock(&event->mmap_mutex);
4755 if (event->rb->nr_pages != nr_pages) {
4760 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4762 * Raced against perf_mmap_close() through
4763 * perf_event_set_output(). Try again, hope for better
4766 mutex_unlock(&event->mmap_mutex);
4773 user_extra = nr_pages + 1;
4776 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4779 * Increase the limit linearly with more CPUs:
4781 user_lock_limit *= num_online_cpus();
4783 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4785 if (user_locked > user_lock_limit)
4786 extra = user_locked - user_lock_limit;
4788 lock_limit = rlimit(RLIMIT_MEMLOCK);
4789 lock_limit >>= PAGE_SHIFT;
4790 locked = vma->vm_mm->pinned_vm + extra;
4792 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4793 !capable(CAP_IPC_LOCK)) {
4798 WARN_ON(!rb && event->rb);
4800 if (vma->vm_flags & VM_WRITE)
4801 flags |= RING_BUFFER_WRITABLE;
4804 rb = rb_alloc(nr_pages,
4805 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4813 atomic_set(&rb->mmap_count, 1);
4814 rb->mmap_user = get_current_user();
4815 rb->mmap_locked = extra;
4817 ring_buffer_attach(event, rb);
4819 perf_event_init_userpage(event);
4820 perf_event_update_userpage(event);
4822 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4823 event->attr.aux_watermark, flags);
4825 rb->aux_mmap_locked = extra;
4830 atomic_long_add(user_extra, &user->locked_vm);
4831 vma->vm_mm->pinned_vm += extra;
4833 atomic_inc(&event->mmap_count);
4835 atomic_dec(&rb->mmap_count);
4838 mutex_unlock(&event->mmap_mutex);
4841 * Since pinned accounting is per vm we cannot allow fork() to copy our
4844 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4845 vma->vm_ops = &perf_mmap_vmops;
4847 if (event->pmu->event_mapped)
4848 event->pmu->event_mapped(event);
4853 static int perf_fasync(int fd, struct file *filp, int on)
4855 struct inode *inode = file_inode(filp);
4856 struct perf_event *event = filp->private_data;
4859 mutex_lock(&inode->i_mutex);
4860 retval = fasync_helper(fd, filp, on, &event->fasync);
4861 mutex_unlock(&inode->i_mutex);
4869 static const struct file_operations perf_fops = {
4870 .llseek = no_llseek,
4871 .release = perf_release,
4874 .unlocked_ioctl = perf_ioctl,
4875 .compat_ioctl = perf_compat_ioctl,
4877 .fasync = perf_fasync,
4883 * If there's data, ensure we set the poll() state and publish everything
4884 * to user-space before waking everybody up.
4887 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4889 /* only the parent has fasync state */
4891 event = event->parent;
4892 return &event->fasync;
4895 void perf_event_wakeup(struct perf_event *event)
4897 ring_buffer_wakeup(event);
4899 if (event->pending_kill) {
4900 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4901 event->pending_kill = 0;
4905 static void perf_pending_event(struct irq_work *entry)
4907 struct perf_event *event = container_of(entry,
4908 struct perf_event, pending);
4911 rctx = perf_swevent_get_recursion_context();
4913 * If we 'fail' here, that's OK, it means recursion is already disabled
4914 * and we won't recurse 'further'.
4917 if (event->pending_disable) {
4918 event->pending_disable = 0;
4919 perf_event_disable_local(event);
4922 if (event->pending_wakeup) {
4923 event->pending_wakeup = 0;
4924 perf_event_wakeup(event);
4928 perf_swevent_put_recursion_context(rctx);
4932 * We assume there is only KVM supporting the callbacks.
4933 * Later on, we might change it to a list if there is
4934 * another virtualization implementation supporting the callbacks.
4936 struct perf_guest_info_callbacks *perf_guest_cbs;
4938 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4940 perf_guest_cbs = cbs;
4943 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4945 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4947 perf_guest_cbs = NULL;
4950 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4953 perf_output_sample_regs(struct perf_output_handle *handle,
4954 struct pt_regs *regs, u64 mask)
4958 for_each_set_bit(bit, (const unsigned long *) &mask,
4959 sizeof(mask) * BITS_PER_BYTE) {
4962 val = perf_reg_value(regs, bit);
4963 perf_output_put(handle, val);
4967 static void perf_sample_regs_user(struct perf_regs *regs_user,
4968 struct pt_regs *regs,
4969 struct pt_regs *regs_user_copy)
4971 if (user_mode(regs)) {
4972 regs_user->abi = perf_reg_abi(current);
4973 regs_user->regs = regs;
4974 } else if (current->mm) {
4975 perf_get_regs_user(regs_user, regs, regs_user_copy);
4977 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4978 regs_user->regs = NULL;
4982 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
4983 struct pt_regs *regs)
4985 regs_intr->regs = regs;
4986 regs_intr->abi = perf_reg_abi(current);
4991 * Get remaining task size from user stack pointer.
4993 * It'd be better to take stack vma map and limit this more
4994 * precisly, but there's no way to get it safely under interrupt,
4995 * so using TASK_SIZE as limit.
4997 static u64 perf_ustack_task_size(struct pt_regs *regs)
4999 unsigned long addr = perf_user_stack_pointer(regs);
5001 if (!addr || addr >= TASK_SIZE)
5004 return TASK_SIZE - addr;
5008 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5009 struct pt_regs *regs)
5013 /* No regs, no stack pointer, no dump. */
5018 * Check if we fit in with the requested stack size into the:
5020 * If we don't, we limit the size to the TASK_SIZE.
5022 * - remaining sample size
5023 * If we don't, we customize the stack size to
5024 * fit in to the remaining sample size.
5027 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5028 stack_size = min(stack_size, (u16) task_size);
5030 /* Current header size plus static size and dynamic size. */
5031 header_size += 2 * sizeof(u64);
5033 /* Do we fit in with the current stack dump size? */
5034 if ((u16) (header_size + stack_size) < header_size) {
5036 * If we overflow the maximum size for the sample,
5037 * we customize the stack dump size to fit in.
5039 stack_size = USHRT_MAX - header_size - sizeof(u64);
5040 stack_size = round_up(stack_size, sizeof(u64));
5047 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5048 struct pt_regs *regs)
5050 /* Case of a kernel thread, nothing to dump */
5053 perf_output_put(handle, size);
5062 * - the size requested by user or the best one we can fit
5063 * in to the sample max size
5065 * - user stack dump data
5067 * - the actual dumped size
5071 perf_output_put(handle, dump_size);
5074 sp = perf_user_stack_pointer(regs);
5075 rem = __output_copy_user(handle, (void *) sp, dump_size);
5076 dyn_size = dump_size - rem;
5078 perf_output_skip(handle, rem);
5081 perf_output_put(handle, dyn_size);
5085 static void __perf_event_header__init_id(struct perf_event_header *header,
5086 struct perf_sample_data *data,
5087 struct perf_event *event)
5089 u64 sample_type = event->attr.sample_type;
5091 data->type = sample_type;
5092 header->size += event->id_header_size;
5094 if (sample_type & PERF_SAMPLE_TID) {
5095 /* namespace issues */
5096 data->tid_entry.pid = perf_event_pid(event, current);
5097 data->tid_entry.tid = perf_event_tid(event, current);
5100 if (sample_type & PERF_SAMPLE_TIME)
5101 data->time = perf_event_clock(event);
5103 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5104 data->id = primary_event_id(event);
5106 if (sample_type & PERF_SAMPLE_STREAM_ID)
5107 data->stream_id = event->id;
5109 if (sample_type & PERF_SAMPLE_CPU) {
5110 data->cpu_entry.cpu = raw_smp_processor_id();
5111 data->cpu_entry.reserved = 0;
5115 void perf_event_header__init_id(struct perf_event_header *header,
5116 struct perf_sample_data *data,
5117 struct perf_event *event)
5119 if (event->attr.sample_id_all)
5120 __perf_event_header__init_id(header, data, event);
5123 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5124 struct perf_sample_data *data)
5126 u64 sample_type = data->type;
5128 if (sample_type & PERF_SAMPLE_TID)
5129 perf_output_put(handle, data->tid_entry);
5131 if (sample_type & PERF_SAMPLE_TIME)
5132 perf_output_put(handle, data->time);
5134 if (sample_type & PERF_SAMPLE_ID)
5135 perf_output_put(handle, data->id);
5137 if (sample_type & PERF_SAMPLE_STREAM_ID)
5138 perf_output_put(handle, data->stream_id);
5140 if (sample_type & PERF_SAMPLE_CPU)
5141 perf_output_put(handle, data->cpu_entry);
5143 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5144 perf_output_put(handle, data->id);
5147 void perf_event__output_id_sample(struct perf_event *event,
5148 struct perf_output_handle *handle,
5149 struct perf_sample_data *sample)
5151 if (event->attr.sample_id_all)
5152 __perf_event__output_id_sample(handle, sample);
5155 static void perf_output_read_one(struct perf_output_handle *handle,
5156 struct perf_event *event,
5157 u64 enabled, u64 running)
5159 u64 read_format = event->attr.read_format;
5163 values[n++] = perf_event_count(event);
5164 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5165 values[n++] = enabled +
5166 atomic64_read(&event->child_total_time_enabled);
5168 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5169 values[n++] = running +
5170 atomic64_read(&event->child_total_time_running);
5172 if (read_format & PERF_FORMAT_ID)
5173 values[n++] = primary_event_id(event);
5175 __output_copy(handle, values, n * sizeof(u64));
5179 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5181 static void perf_output_read_group(struct perf_output_handle *handle,
5182 struct perf_event *event,
5183 u64 enabled, u64 running)
5185 struct perf_event *leader = event->group_leader, *sub;
5186 u64 read_format = event->attr.read_format;
5190 values[n++] = 1 + leader->nr_siblings;
5192 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5193 values[n++] = enabled;
5195 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5196 values[n++] = running;
5198 if (leader != event)
5199 leader->pmu->read(leader);
5201 values[n++] = perf_event_count(leader);
5202 if (read_format & PERF_FORMAT_ID)
5203 values[n++] = primary_event_id(leader);
5205 __output_copy(handle, values, n * sizeof(u64));
5207 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5210 if ((sub != event) &&
5211 (sub->state == PERF_EVENT_STATE_ACTIVE))
5212 sub->pmu->read(sub);
5214 values[n++] = perf_event_count(sub);
5215 if (read_format & PERF_FORMAT_ID)
5216 values[n++] = primary_event_id(sub);
5218 __output_copy(handle, values, n * sizeof(u64));
5222 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5223 PERF_FORMAT_TOTAL_TIME_RUNNING)
5225 static void perf_output_read(struct perf_output_handle *handle,
5226 struct perf_event *event)
5228 u64 enabled = 0, running = 0, now;
5229 u64 read_format = event->attr.read_format;
5232 * compute total_time_enabled, total_time_running
5233 * based on snapshot values taken when the event
5234 * was last scheduled in.
5236 * we cannot simply called update_context_time()
5237 * because of locking issue as we are called in
5240 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5241 calc_timer_values(event, &now, &enabled, &running);
5243 if (event->attr.read_format & PERF_FORMAT_GROUP)
5244 perf_output_read_group(handle, event, enabled, running);
5246 perf_output_read_one(handle, event, enabled, running);
5249 void perf_output_sample(struct perf_output_handle *handle,
5250 struct perf_event_header *header,
5251 struct perf_sample_data *data,
5252 struct perf_event *event)
5254 u64 sample_type = data->type;
5256 perf_output_put(handle, *header);
5258 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5259 perf_output_put(handle, data->id);
5261 if (sample_type & PERF_SAMPLE_IP)
5262 perf_output_put(handle, data->ip);
5264 if (sample_type & PERF_SAMPLE_TID)
5265 perf_output_put(handle, data->tid_entry);
5267 if (sample_type & PERF_SAMPLE_TIME)
5268 perf_output_put(handle, data->time);
5270 if (sample_type & PERF_SAMPLE_ADDR)
5271 perf_output_put(handle, data->addr);
5273 if (sample_type & PERF_SAMPLE_ID)
5274 perf_output_put(handle, data->id);
5276 if (sample_type & PERF_SAMPLE_STREAM_ID)
5277 perf_output_put(handle, data->stream_id);
5279 if (sample_type & PERF_SAMPLE_CPU)
5280 perf_output_put(handle, data->cpu_entry);
5282 if (sample_type & PERF_SAMPLE_PERIOD)
5283 perf_output_put(handle, data->period);
5285 if (sample_type & PERF_SAMPLE_READ)
5286 perf_output_read(handle, event);
5288 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5289 if (data->callchain) {
5292 if (data->callchain)
5293 size += data->callchain->nr;
5295 size *= sizeof(u64);
5297 __output_copy(handle, data->callchain, size);
5300 perf_output_put(handle, nr);
5304 if (sample_type & PERF_SAMPLE_RAW) {
5306 u32 raw_size = data->raw->size;
5307 u32 real_size = round_up(raw_size + sizeof(u32),
5308 sizeof(u64)) - sizeof(u32);
5311 perf_output_put(handle, real_size);
5312 __output_copy(handle, data->raw->data, raw_size);
5313 if (real_size - raw_size)
5314 __output_copy(handle, &zero, real_size - raw_size);
5320 .size = sizeof(u32),
5323 perf_output_put(handle, raw);
5327 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5328 if (data->br_stack) {
5331 size = data->br_stack->nr
5332 * sizeof(struct perf_branch_entry);
5334 perf_output_put(handle, data->br_stack->nr);
5335 perf_output_copy(handle, data->br_stack->entries, size);
5338 * we always store at least the value of nr
5341 perf_output_put(handle, nr);
5345 if (sample_type & PERF_SAMPLE_REGS_USER) {
5346 u64 abi = data->regs_user.abi;
5349 * If there are no regs to dump, notice it through
5350 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5352 perf_output_put(handle, abi);
5355 u64 mask = event->attr.sample_regs_user;
5356 perf_output_sample_regs(handle,
5357 data->regs_user.regs,
5362 if (sample_type & PERF_SAMPLE_STACK_USER) {
5363 perf_output_sample_ustack(handle,
5364 data->stack_user_size,
5365 data->regs_user.regs);
5368 if (sample_type & PERF_SAMPLE_WEIGHT)
5369 perf_output_put(handle, data->weight);
5371 if (sample_type & PERF_SAMPLE_DATA_SRC)
5372 perf_output_put(handle, data->data_src.val);
5374 if (sample_type & PERF_SAMPLE_TRANSACTION)
5375 perf_output_put(handle, data->txn);
5377 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5378 u64 abi = data->regs_intr.abi;
5380 * If there are no regs to dump, notice it through
5381 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5383 perf_output_put(handle, abi);
5386 u64 mask = event->attr.sample_regs_intr;
5388 perf_output_sample_regs(handle,
5389 data->regs_intr.regs,
5394 if (!event->attr.watermark) {
5395 int wakeup_events = event->attr.wakeup_events;
5397 if (wakeup_events) {
5398 struct ring_buffer *rb = handle->rb;
5399 int events = local_inc_return(&rb->events);
5401 if (events >= wakeup_events) {
5402 local_sub(wakeup_events, &rb->events);
5403 local_inc(&rb->wakeup);
5409 void perf_prepare_sample(struct perf_event_header *header,
5410 struct perf_sample_data *data,
5411 struct perf_event *event,
5412 struct pt_regs *regs)
5414 u64 sample_type = event->attr.sample_type;
5416 header->type = PERF_RECORD_SAMPLE;
5417 header->size = sizeof(*header) + event->header_size;
5420 header->misc |= perf_misc_flags(regs);
5422 __perf_event_header__init_id(header, data, event);
5424 if (sample_type & PERF_SAMPLE_IP)
5425 data->ip = perf_instruction_pointer(regs);
5427 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5430 data->callchain = perf_callchain(event, regs);
5432 if (data->callchain)
5433 size += data->callchain->nr;
5435 header->size += size * sizeof(u64);
5438 if (sample_type & PERF_SAMPLE_RAW) {
5439 int size = sizeof(u32);
5442 size += data->raw->size;
5444 size += sizeof(u32);
5446 header->size += round_up(size, sizeof(u64));
5449 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5450 int size = sizeof(u64); /* nr */
5451 if (data->br_stack) {
5452 size += data->br_stack->nr
5453 * sizeof(struct perf_branch_entry);
5455 header->size += size;
5458 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5459 perf_sample_regs_user(&data->regs_user, regs,
5460 &data->regs_user_copy);
5462 if (sample_type & PERF_SAMPLE_REGS_USER) {
5463 /* regs dump ABI info */
5464 int size = sizeof(u64);
5466 if (data->regs_user.regs) {
5467 u64 mask = event->attr.sample_regs_user;
5468 size += hweight64(mask) * sizeof(u64);
5471 header->size += size;
5474 if (sample_type & PERF_SAMPLE_STACK_USER) {
5476 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5477 * processed as the last one or have additional check added
5478 * in case new sample type is added, because we could eat
5479 * up the rest of the sample size.
5481 u16 stack_size = event->attr.sample_stack_user;
5482 u16 size = sizeof(u64);
5484 stack_size = perf_sample_ustack_size(stack_size, header->size,
5485 data->regs_user.regs);
5488 * If there is something to dump, add space for the dump
5489 * itself and for the field that tells the dynamic size,
5490 * which is how many have been actually dumped.
5493 size += sizeof(u64) + stack_size;
5495 data->stack_user_size = stack_size;
5496 header->size += size;
5499 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5500 /* regs dump ABI info */
5501 int size = sizeof(u64);
5503 perf_sample_regs_intr(&data->regs_intr, regs);
5505 if (data->regs_intr.regs) {
5506 u64 mask = event->attr.sample_regs_intr;
5508 size += hweight64(mask) * sizeof(u64);
5511 header->size += size;
5515 void perf_event_output(struct perf_event *event,
5516 struct perf_sample_data *data,
5517 struct pt_regs *regs)
5519 struct perf_output_handle handle;
5520 struct perf_event_header header;
5522 /* protect the callchain buffers */
5525 perf_prepare_sample(&header, data, event, regs);
5527 if (perf_output_begin(&handle, event, header.size))
5530 perf_output_sample(&handle, &header, data, event);
5532 perf_output_end(&handle);
5542 struct perf_read_event {
5543 struct perf_event_header header;
5550 perf_event_read_event(struct perf_event *event,
5551 struct task_struct *task)
5553 struct perf_output_handle handle;
5554 struct perf_sample_data sample;
5555 struct perf_read_event read_event = {
5557 .type = PERF_RECORD_READ,
5559 .size = sizeof(read_event) + event->read_size,
5561 .pid = perf_event_pid(event, task),
5562 .tid = perf_event_tid(event, task),
5566 perf_event_header__init_id(&read_event.header, &sample, event);
5567 ret = perf_output_begin(&handle, event, read_event.header.size);
5571 perf_output_put(&handle, read_event);
5572 perf_output_read(&handle, event);
5573 perf_event__output_id_sample(event, &handle, &sample);
5575 perf_output_end(&handle);
5578 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5581 perf_event_aux_ctx(struct perf_event_context *ctx,
5582 perf_event_aux_output_cb output,
5585 struct perf_event *event;
5587 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5588 if (event->state < PERF_EVENT_STATE_INACTIVE)
5590 if (!event_filter_match(event))
5592 output(event, data);
5597 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5598 struct perf_event_context *task_ctx)
5602 perf_event_aux_ctx(task_ctx, output, data);
5608 perf_event_aux(perf_event_aux_output_cb output, void *data,
5609 struct perf_event_context *task_ctx)
5611 struct perf_cpu_context *cpuctx;
5612 struct perf_event_context *ctx;
5617 * If we have task_ctx != NULL we only notify
5618 * the task context itself. The task_ctx is set
5619 * only for EXIT events before releasing task
5623 perf_event_aux_task_ctx(output, data, task_ctx);
5628 list_for_each_entry_rcu(pmu, &pmus, entry) {
5629 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5630 if (cpuctx->unique_pmu != pmu)
5632 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5633 ctxn = pmu->task_ctx_nr;
5636 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5638 perf_event_aux_ctx(ctx, output, data);
5640 put_cpu_ptr(pmu->pmu_cpu_context);
5646 * task tracking -- fork/exit
5648 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5651 struct perf_task_event {
5652 struct task_struct *task;
5653 struct perf_event_context *task_ctx;
5656 struct perf_event_header header;
5666 static int perf_event_task_match(struct perf_event *event)
5668 return event->attr.comm || event->attr.mmap ||
5669 event->attr.mmap2 || event->attr.mmap_data ||
5673 static void perf_event_task_output(struct perf_event *event,
5676 struct perf_task_event *task_event = data;
5677 struct perf_output_handle handle;
5678 struct perf_sample_data sample;
5679 struct task_struct *task = task_event->task;
5680 int ret, size = task_event->event_id.header.size;
5682 if (!perf_event_task_match(event))
5685 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5687 ret = perf_output_begin(&handle, event,
5688 task_event->event_id.header.size);
5692 task_event->event_id.pid = perf_event_pid(event, task);
5693 task_event->event_id.ppid = perf_event_pid(event, current);
5695 task_event->event_id.tid = perf_event_tid(event, task);
5696 task_event->event_id.ptid = perf_event_tid(event, current);
5698 task_event->event_id.time = perf_event_clock(event);
5700 perf_output_put(&handle, task_event->event_id);
5702 perf_event__output_id_sample(event, &handle, &sample);
5704 perf_output_end(&handle);
5706 task_event->event_id.header.size = size;
5709 static void perf_event_task(struct task_struct *task,
5710 struct perf_event_context *task_ctx,
5713 struct perf_task_event task_event;
5715 if (!atomic_read(&nr_comm_events) &&
5716 !atomic_read(&nr_mmap_events) &&
5717 !atomic_read(&nr_task_events))
5720 task_event = (struct perf_task_event){
5722 .task_ctx = task_ctx,
5725 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5727 .size = sizeof(task_event.event_id),
5737 perf_event_aux(perf_event_task_output,
5742 void perf_event_fork(struct task_struct *task)
5744 perf_event_task(task, NULL, 1);
5751 struct perf_comm_event {
5752 struct task_struct *task;
5757 struct perf_event_header header;
5764 static int perf_event_comm_match(struct perf_event *event)
5766 return event->attr.comm;
5769 static void perf_event_comm_output(struct perf_event *event,
5772 struct perf_comm_event *comm_event = data;
5773 struct perf_output_handle handle;
5774 struct perf_sample_data sample;
5775 int size = comm_event->event_id.header.size;
5778 if (!perf_event_comm_match(event))
5781 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5782 ret = perf_output_begin(&handle, event,
5783 comm_event->event_id.header.size);
5788 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5789 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5791 perf_output_put(&handle, comm_event->event_id);
5792 __output_copy(&handle, comm_event->comm,
5793 comm_event->comm_size);
5795 perf_event__output_id_sample(event, &handle, &sample);
5797 perf_output_end(&handle);
5799 comm_event->event_id.header.size = size;
5802 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5804 char comm[TASK_COMM_LEN];
5807 memset(comm, 0, sizeof(comm));
5808 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5809 size = ALIGN(strlen(comm)+1, sizeof(u64));
5811 comm_event->comm = comm;
5812 comm_event->comm_size = size;
5814 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5816 perf_event_aux(perf_event_comm_output,
5821 void perf_event_comm(struct task_struct *task, bool exec)
5823 struct perf_comm_event comm_event;
5825 if (!atomic_read(&nr_comm_events))
5828 comm_event = (struct perf_comm_event){
5834 .type = PERF_RECORD_COMM,
5835 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5843 perf_event_comm_event(&comm_event);
5850 struct perf_mmap_event {
5851 struct vm_area_struct *vma;
5853 const char *file_name;
5861 struct perf_event_header header;
5871 static int perf_event_mmap_match(struct perf_event *event,
5874 struct perf_mmap_event *mmap_event = data;
5875 struct vm_area_struct *vma = mmap_event->vma;
5876 int executable = vma->vm_flags & VM_EXEC;
5878 return (!executable && event->attr.mmap_data) ||
5879 (executable && (event->attr.mmap || event->attr.mmap2));
5882 static void perf_event_mmap_output(struct perf_event *event,
5885 struct perf_mmap_event *mmap_event = data;
5886 struct perf_output_handle handle;
5887 struct perf_sample_data sample;
5888 int size = mmap_event->event_id.header.size;
5891 if (!perf_event_mmap_match(event, data))
5894 if (event->attr.mmap2) {
5895 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5896 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5897 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5898 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5899 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5900 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5901 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5904 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5905 ret = perf_output_begin(&handle, event,
5906 mmap_event->event_id.header.size);
5910 mmap_event->event_id.pid = perf_event_pid(event, current);
5911 mmap_event->event_id.tid = perf_event_tid(event, current);
5913 perf_output_put(&handle, mmap_event->event_id);
5915 if (event->attr.mmap2) {
5916 perf_output_put(&handle, mmap_event->maj);
5917 perf_output_put(&handle, mmap_event->min);
5918 perf_output_put(&handle, mmap_event->ino);
5919 perf_output_put(&handle, mmap_event->ino_generation);
5920 perf_output_put(&handle, mmap_event->prot);
5921 perf_output_put(&handle, mmap_event->flags);
5924 __output_copy(&handle, mmap_event->file_name,
5925 mmap_event->file_size);
5927 perf_event__output_id_sample(event, &handle, &sample);
5929 perf_output_end(&handle);
5931 mmap_event->event_id.header.size = size;
5934 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5936 struct vm_area_struct *vma = mmap_event->vma;
5937 struct file *file = vma->vm_file;
5938 int maj = 0, min = 0;
5939 u64 ino = 0, gen = 0;
5940 u32 prot = 0, flags = 0;
5947 struct inode *inode;
5950 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5956 * d_path() works from the end of the rb backwards, so we
5957 * need to add enough zero bytes after the string to handle
5958 * the 64bit alignment we do later.
5960 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5965 inode = file_inode(vma->vm_file);
5966 dev = inode->i_sb->s_dev;
5968 gen = inode->i_generation;
5972 if (vma->vm_flags & VM_READ)
5974 if (vma->vm_flags & VM_WRITE)
5976 if (vma->vm_flags & VM_EXEC)
5979 if (vma->vm_flags & VM_MAYSHARE)
5982 flags = MAP_PRIVATE;
5984 if (vma->vm_flags & VM_DENYWRITE)
5985 flags |= MAP_DENYWRITE;
5986 if (vma->vm_flags & VM_MAYEXEC)
5987 flags |= MAP_EXECUTABLE;
5988 if (vma->vm_flags & VM_LOCKED)
5989 flags |= MAP_LOCKED;
5990 if (vma->vm_flags & VM_HUGETLB)
5991 flags |= MAP_HUGETLB;
5995 if (vma->vm_ops && vma->vm_ops->name) {
5996 name = (char *) vma->vm_ops->name(vma);
6001 name = (char *)arch_vma_name(vma);
6005 if (vma->vm_start <= vma->vm_mm->start_brk &&
6006 vma->vm_end >= vma->vm_mm->brk) {
6010 if (vma->vm_start <= vma->vm_mm->start_stack &&
6011 vma->vm_end >= vma->vm_mm->start_stack) {
6021 strlcpy(tmp, name, sizeof(tmp));
6025 * Since our buffer works in 8 byte units we need to align our string
6026 * size to a multiple of 8. However, we must guarantee the tail end is
6027 * zero'd out to avoid leaking random bits to userspace.
6029 size = strlen(name)+1;
6030 while (!IS_ALIGNED(size, sizeof(u64)))
6031 name[size++] = '\0';
6033 mmap_event->file_name = name;
6034 mmap_event->file_size = size;
6035 mmap_event->maj = maj;
6036 mmap_event->min = min;
6037 mmap_event->ino = ino;
6038 mmap_event->ino_generation = gen;
6039 mmap_event->prot = prot;
6040 mmap_event->flags = flags;
6042 if (!(vma->vm_flags & VM_EXEC))
6043 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6045 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6047 perf_event_aux(perf_event_mmap_output,
6054 void perf_event_mmap(struct vm_area_struct *vma)
6056 struct perf_mmap_event mmap_event;
6058 if (!atomic_read(&nr_mmap_events))
6061 mmap_event = (struct perf_mmap_event){
6067 .type = PERF_RECORD_MMAP,
6068 .misc = PERF_RECORD_MISC_USER,
6073 .start = vma->vm_start,
6074 .len = vma->vm_end - vma->vm_start,
6075 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6077 /* .maj (attr_mmap2 only) */
6078 /* .min (attr_mmap2 only) */
6079 /* .ino (attr_mmap2 only) */
6080 /* .ino_generation (attr_mmap2 only) */
6081 /* .prot (attr_mmap2 only) */
6082 /* .flags (attr_mmap2 only) */
6085 perf_event_mmap_event(&mmap_event);
6088 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6089 unsigned long size, u64 flags)
6091 struct perf_output_handle handle;
6092 struct perf_sample_data sample;
6093 struct perf_aux_event {
6094 struct perf_event_header header;
6100 .type = PERF_RECORD_AUX,
6102 .size = sizeof(rec),
6110 perf_event_header__init_id(&rec.header, &sample, event);
6111 ret = perf_output_begin(&handle, event, rec.header.size);
6116 perf_output_put(&handle, rec);
6117 perf_event__output_id_sample(event, &handle, &sample);
6119 perf_output_end(&handle);
6123 * Lost/dropped samples logging
6125 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6127 struct perf_output_handle handle;
6128 struct perf_sample_data sample;
6132 struct perf_event_header header;
6134 } lost_samples_event = {
6136 .type = PERF_RECORD_LOST_SAMPLES,
6138 .size = sizeof(lost_samples_event),
6143 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6145 ret = perf_output_begin(&handle, event,
6146 lost_samples_event.header.size);
6150 perf_output_put(&handle, lost_samples_event);
6151 perf_event__output_id_sample(event, &handle, &sample);
6152 perf_output_end(&handle);
6156 * context_switch tracking
6159 struct perf_switch_event {
6160 struct task_struct *task;
6161 struct task_struct *next_prev;
6164 struct perf_event_header header;
6170 static int perf_event_switch_match(struct perf_event *event)
6172 return event->attr.context_switch;
6175 static void perf_event_switch_output(struct perf_event *event, void *data)
6177 struct perf_switch_event *se = data;
6178 struct perf_output_handle handle;
6179 struct perf_sample_data sample;
6182 if (!perf_event_switch_match(event))
6185 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6186 if (event->ctx->task) {
6187 se->event_id.header.type = PERF_RECORD_SWITCH;
6188 se->event_id.header.size = sizeof(se->event_id.header);
6190 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6191 se->event_id.header.size = sizeof(se->event_id);
6192 se->event_id.next_prev_pid =
6193 perf_event_pid(event, se->next_prev);
6194 se->event_id.next_prev_tid =
6195 perf_event_tid(event, se->next_prev);
6198 perf_event_header__init_id(&se->event_id.header, &sample, event);
6200 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6204 if (event->ctx->task)
6205 perf_output_put(&handle, se->event_id.header);
6207 perf_output_put(&handle, se->event_id);
6209 perf_event__output_id_sample(event, &handle, &sample);
6211 perf_output_end(&handle);
6214 static void perf_event_switch(struct task_struct *task,
6215 struct task_struct *next_prev, bool sched_in)
6217 struct perf_switch_event switch_event;
6219 /* N.B. caller checks nr_switch_events != 0 */
6221 switch_event = (struct perf_switch_event){
6223 .next_prev = next_prev,
6227 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6230 /* .next_prev_pid */
6231 /* .next_prev_tid */
6235 perf_event_aux(perf_event_switch_output,
6241 * IRQ throttle logging
6244 static void perf_log_throttle(struct perf_event *event, int enable)
6246 struct perf_output_handle handle;
6247 struct perf_sample_data sample;
6251 struct perf_event_header header;
6255 } throttle_event = {
6257 .type = PERF_RECORD_THROTTLE,
6259 .size = sizeof(throttle_event),
6261 .time = perf_event_clock(event),
6262 .id = primary_event_id(event),
6263 .stream_id = event->id,
6267 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6269 perf_event_header__init_id(&throttle_event.header, &sample, event);
6271 ret = perf_output_begin(&handle, event,
6272 throttle_event.header.size);
6276 perf_output_put(&handle, throttle_event);
6277 perf_event__output_id_sample(event, &handle, &sample);
6278 perf_output_end(&handle);
6281 static void perf_log_itrace_start(struct perf_event *event)
6283 struct perf_output_handle handle;
6284 struct perf_sample_data sample;
6285 struct perf_aux_event {
6286 struct perf_event_header header;
6293 event = event->parent;
6295 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6296 event->hw.itrace_started)
6299 rec.header.type = PERF_RECORD_ITRACE_START;
6300 rec.header.misc = 0;
6301 rec.header.size = sizeof(rec);
6302 rec.pid = perf_event_pid(event, current);
6303 rec.tid = perf_event_tid(event, current);
6305 perf_event_header__init_id(&rec.header, &sample, event);
6306 ret = perf_output_begin(&handle, event, rec.header.size);
6311 perf_output_put(&handle, rec);
6312 perf_event__output_id_sample(event, &handle, &sample);
6314 perf_output_end(&handle);
6318 * Generic event overflow handling, sampling.
6321 static int __perf_event_overflow(struct perf_event *event,
6322 int throttle, struct perf_sample_data *data,
6323 struct pt_regs *regs)
6325 int events = atomic_read(&event->event_limit);
6326 struct hw_perf_event *hwc = &event->hw;
6331 * Non-sampling counters might still use the PMI to fold short
6332 * hardware counters, ignore those.
6334 if (unlikely(!is_sampling_event(event)))
6337 seq = __this_cpu_read(perf_throttled_seq);
6338 if (seq != hwc->interrupts_seq) {
6339 hwc->interrupts_seq = seq;
6340 hwc->interrupts = 1;
6343 if (unlikely(throttle
6344 && hwc->interrupts >= max_samples_per_tick)) {
6345 __this_cpu_inc(perf_throttled_count);
6346 hwc->interrupts = MAX_INTERRUPTS;
6347 perf_log_throttle(event, 0);
6348 tick_nohz_full_kick();
6353 if (event->attr.freq) {
6354 u64 now = perf_clock();
6355 s64 delta = now - hwc->freq_time_stamp;
6357 hwc->freq_time_stamp = now;
6359 if (delta > 0 && delta < 2*TICK_NSEC)
6360 perf_adjust_period(event, delta, hwc->last_period, true);
6364 * XXX event_limit might not quite work as expected on inherited
6368 event->pending_kill = POLL_IN;
6369 if (events && atomic_dec_and_test(&event->event_limit)) {
6371 event->pending_kill = POLL_HUP;
6372 event->pending_disable = 1;
6373 irq_work_queue(&event->pending);
6376 if (event->overflow_handler)
6377 event->overflow_handler(event, data, regs);
6379 perf_event_output(event, data, regs);
6381 if (*perf_event_fasync(event) && event->pending_kill) {
6382 event->pending_wakeup = 1;
6383 irq_work_queue(&event->pending);
6389 int perf_event_overflow(struct perf_event *event,
6390 struct perf_sample_data *data,
6391 struct pt_regs *regs)
6393 return __perf_event_overflow(event, 1, data, regs);
6397 * Generic software event infrastructure
6400 struct swevent_htable {
6401 struct swevent_hlist *swevent_hlist;
6402 struct mutex hlist_mutex;
6405 /* Recursion avoidance in each contexts */
6406 int recursion[PERF_NR_CONTEXTS];
6409 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6412 * We directly increment event->count and keep a second value in
6413 * event->hw.period_left to count intervals. This period event
6414 * is kept in the range [-sample_period, 0] so that we can use the
6418 u64 perf_swevent_set_period(struct perf_event *event)
6420 struct hw_perf_event *hwc = &event->hw;
6421 u64 period = hwc->last_period;
6425 hwc->last_period = hwc->sample_period;
6428 old = val = local64_read(&hwc->period_left);
6432 nr = div64_u64(period + val, period);
6433 offset = nr * period;
6435 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6441 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6442 struct perf_sample_data *data,
6443 struct pt_regs *regs)
6445 struct hw_perf_event *hwc = &event->hw;
6449 overflow = perf_swevent_set_period(event);
6451 if (hwc->interrupts == MAX_INTERRUPTS)
6454 for (; overflow; overflow--) {
6455 if (__perf_event_overflow(event, throttle,
6458 * We inhibit the overflow from happening when
6459 * hwc->interrupts == MAX_INTERRUPTS.
6467 static void perf_swevent_event(struct perf_event *event, u64 nr,
6468 struct perf_sample_data *data,
6469 struct pt_regs *regs)
6471 struct hw_perf_event *hwc = &event->hw;
6473 local64_add(nr, &event->count);
6478 if (!is_sampling_event(event))
6481 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6483 return perf_swevent_overflow(event, 1, data, regs);
6485 data->period = event->hw.last_period;
6487 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6488 return perf_swevent_overflow(event, 1, data, regs);
6490 if (local64_add_negative(nr, &hwc->period_left))
6493 perf_swevent_overflow(event, 0, data, regs);
6496 static int perf_exclude_event(struct perf_event *event,
6497 struct pt_regs *regs)
6499 if (event->hw.state & PERF_HES_STOPPED)
6503 if (event->attr.exclude_user && user_mode(regs))
6506 if (event->attr.exclude_kernel && !user_mode(regs))
6513 static int perf_swevent_match(struct perf_event *event,
6514 enum perf_type_id type,
6516 struct perf_sample_data *data,
6517 struct pt_regs *regs)
6519 if (event->attr.type != type)
6522 if (event->attr.config != event_id)
6525 if (perf_exclude_event(event, regs))
6531 static inline u64 swevent_hash(u64 type, u32 event_id)
6533 u64 val = event_id | (type << 32);
6535 return hash_64(val, SWEVENT_HLIST_BITS);
6538 static inline struct hlist_head *
6539 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6541 u64 hash = swevent_hash(type, event_id);
6543 return &hlist->heads[hash];
6546 /* For the read side: events when they trigger */
6547 static inline struct hlist_head *
6548 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6550 struct swevent_hlist *hlist;
6552 hlist = rcu_dereference(swhash->swevent_hlist);
6556 return __find_swevent_head(hlist, type, event_id);
6559 /* For the event head insertion and removal in the hlist */
6560 static inline struct hlist_head *
6561 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6563 struct swevent_hlist *hlist;
6564 u32 event_id = event->attr.config;
6565 u64 type = event->attr.type;
6568 * Event scheduling is always serialized against hlist allocation
6569 * and release. Which makes the protected version suitable here.
6570 * The context lock guarantees that.
6572 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6573 lockdep_is_held(&event->ctx->lock));
6577 return __find_swevent_head(hlist, type, event_id);
6580 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6582 struct perf_sample_data *data,
6583 struct pt_regs *regs)
6585 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6586 struct perf_event *event;
6587 struct hlist_head *head;
6590 head = find_swevent_head_rcu(swhash, type, event_id);
6594 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6595 if (perf_swevent_match(event, type, event_id, data, regs))
6596 perf_swevent_event(event, nr, data, regs);
6602 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6604 int perf_swevent_get_recursion_context(void)
6606 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6608 return get_recursion_context(swhash->recursion);
6610 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6612 inline void perf_swevent_put_recursion_context(int rctx)
6614 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6616 put_recursion_context(swhash->recursion, rctx);
6619 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6621 struct perf_sample_data data;
6623 if (WARN_ON_ONCE(!regs))
6626 perf_sample_data_init(&data, addr, 0);
6627 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6630 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6634 preempt_disable_notrace();
6635 rctx = perf_swevent_get_recursion_context();
6636 if (unlikely(rctx < 0))
6639 ___perf_sw_event(event_id, nr, regs, addr);
6641 perf_swevent_put_recursion_context(rctx);
6643 preempt_enable_notrace();
6646 static void perf_swevent_read(struct perf_event *event)
6650 static int perf_swevent_add(struct perf_event *event, int flags)
6652 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6653 struct hw_perf_event *hwc = &event->hw;
6654 struct hlist_head *head;
6656 if (is_sampling_event(event)) {
6657 hwc->last_period = hwc->sample_period;
6658 perf_swevent_set_period(event);
6661 hwc->state = !(flags & PERF_EF_START);
6663 head = find_swevent_head(swhash, event);
6664 if (WARN_ON_ONCE(!head))
6667 hlist_add_head_rcu(&event->hlist_entry, head);
6668 perf_event_update_userpage(event);
6673 static void perf_swevent_del(struct perf_event *event, int flags)
6675 hlist_del_rcu(&event->hlist_entry);
6678 static void perf_swevent_start(struct perf_event *event, int flags)
6680 event->hw.state = 0;
6683 static void perf_swevent_stop(struct perf_event *event, int flags)
6685 event->hw.state = PERF_HES_STOPPED;
6688 /* Deref the hlist from the update side */
6689 static inline struct swevent_hlist *
6690 swevent_hlist_deref(struct swevent_htable *swhash)
6692 return rcu_dereference_protected(swhash->swevent_hlist,
6693 lockdep_is_held(&swhash->hlist_mutex));
6696 static void swevent_hlist_release(struct swevent_htable *swhash)
6698 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6703 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6704 kfree_rcu(hlist, rcu_head);
6707 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6709 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6711 mutex_lock(&swhash->hlist_mutex);
6713 if (!--swhash->hlist_refcount)
6714 swevent_hlist_release(swhash);
6716 mutex_unlock(&swhash->hlist_mutex);
6719 static void swevent_hlist_put(struct perf_event *event)
6723 for_each_possible_cpu(cpu)
6724 swevent_hlist_put_cpu(event, cpu);
6727 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6729 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6732 mutex_lock(&swhash->hlist_mutex);
6733 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6734 struct swevent_hlist *hlist;
6736 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6741 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6743 swhash->hlist_refcount++;
6745 mutex_unlock(&swhash->hlist_mutex);
6750 static int swevent_hlist_get(struct perf_event *event)
6753 int cpu, failed_cpu;
6756 for_each_possible_cpu(cpu) {
6757 err = swevent_hlist_get_cpu(event, cpu);
6767 for_each_possible_cpu(cpu) {
6768 if (cpu == failed_cpu)
6770 swevent_hlist_put_cpu(event, cpu);
6777 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6779 static void sw_perf_event_destroy(struct perf_event *event)
6781 u64 event_id = event->attr.config;
6783 WARN_ON(event->parent);
6785 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6786 swevent_hlist_put(event);
6789 static int perf_swevent_init(struct perf_event *event)
6791 u64 event_id = event->attr.config;
6793 if (event->attr.type != PERF_TYPE_SOFTWARE)
6797 * no branch sampling for software events
6799 if (has_branch_stack(event))
6803 case PERF_COUNT_SW_CPU_CLOCK:
6804 case PERF_COUNT_SW_TASK_CLOCK:
6811 if (event_id >= PERF_COUNT_SW_MAX)
6814 if (!event->parent) {
6817 err = swevent_hlist_get(event);
6821 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6822 event->destroy = sw_perf_event_destroy;
6828 static struct pmu perf_swevent = {
6829 .task_ctx_nr = perf_sw_context,
6831 .capabilities = PERF_PMU_CAP_NO_NMI,
6833 .event_init = perf_swevent_init,
6834 .add = perf_swevent_add,
6835 .del = perf_swevent_del,
6836 .start = perf_swevent_start,
6837 .stop = perf_swevent_stop,
6838 .read = perf_swevent_read,
6841 #ifdef CONFIG_EVENT_TRACING
6843 static int perf_tp_filter_match(struct perf_event *event,
6844 struct perf_sample_data *data)
6846 void *record = data->raw->data;
6848 /* only top level events have filters set */
6850 event = event->parent;
6852 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6857 static int perf_tp_event_match(struct perf_event *event,
6858 struct perf_sample_data *data,
6859 struct pt_regs *regs)
6861 if (event->hw.state & PERF_HES_STOPPED)
6864 * All tracepoints are from kernel-space.
6866 if (event->attr.exclude_kernel)
6869 if (!perf_tp_filter_match(event, data))
6875 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6876 struct pt_regs *regs, struct hlist_head *head, int rctx,
6877 struct task_struct *task)
6879 struct perf_sample_data data;
6880 struct perf_event *event;
6882 struct perf_raw_record raw = {
6887 perf_sample_data_init(&data, addr, 0);
6890 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6891 if (perf_tp_event_match(event, &data, regs))
6892 perf_swevent_event(event, count, &data, regs);
6896 * If we got specified a target task, also iterate its context and
6897 * deliver this event there too.
6899 if (task && task != current) {
6900 struct perf_event_context *ctx;
6901 struct trace_entry *entry = record;
6904 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6908 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6909 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6911 if (event->attr.config != entry->type)
6913 if (perf_tp_event_match(event, &data, regs))
6914 perf_swevent_event(event, count, &data, regs);
6920 perf_swevent_put_recursion_context(rctx);
6922 EXPORT_SYMBOL_GPL(perf_tp_event);
6924 static void tp_perf_event_destroy(struct perf_event *event)
6926 perf_trace_destroy(event);
6929 static int perf_tp_event_init(struct perf_event *event)
6933 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6937 * no branch sampling for tracepoint events
6939 if (has_branch_stack(event))
6942 err = perf_trace_init(event);
6946 event->destroy = tp_perf_event_destroy;
6951 static struct pmu perf_tracepoint = {
6952 .task_ctx_nr = perf_sw_context,
6954 .event_init = perf_tp_event_init,
6955 .add = perf_trace_add,
6956 .del = perf_trace_del,
6957 .start = perf_swevent_start,
6958 .stop = perf_swevent_stop,
6959 .read = perf_swevent_read,
6962 static inline void perf_tp_register(void)
6964 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6967 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6972 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6975 filter_str = strndup_user(arg, PAGE_SIZE);
6976 if (IS_ERR(filter_str))
6977 return PTR_ERR(filter_str);
6979 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
6985 static void perf_event_free_filter(struct perf_event *event)
6987 ftrace_profile_free_filter(event);
6990 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
6992 struct bpf_prog *prog;
6994 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6997 if (event->tp_event->prog)
7000 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7001 /* bpf programs can only be attached to u/kprobes */
7004 prog = bpf_prog_get(prog_fd);
7006 return PTR_ERR(prog);
7008 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7009 /* valid fd, but invalid bpf program type */
7014 event->tp_event->prog = prog;
7019 static void perf_event_free_bpf_prog(struct perf_event *event)
7021 struct bpf_prog *prog;
7023 if (!event->tp_event)
7026 prog = event->tp_event->prog;
7028 event->tp_event->prog = NULL;
7035 static inline void perf_tp_register(void)
7039 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7044 static void perf_event_free_filter(struct perf_event *event)
7048 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7053 static void perf_event_free_bpf_prog(struct perf_event *event)
7056 #endif /* CONFIG_EVENT_TRACING */
7058 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7059 void perf_bp_event(struct perf_event *bp, void *data)
7061 struct perf_sample_data sample;
7062 struct pt_regs *regs = data;
7064 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7066 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7067 perf_swevent_event(bp, 1, &sample, regs);
7072 * hrtimer based swevent callback
7075 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7077 enum hrtimer_restart ret = HRTIMER_RESTART;
7078 struct perf_sample_data data;
7079 struct pt_regs *regs;
7080 struct perf_event *event;
7083 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7085 if (event->state != PERF_EVENT_STATE_ACTIVE)
7086 return HRTIMER_NORESTART;
7088 event->pmu->read(event);
7090 perf_sample_data_init(&data, 0, event->hw.last_period);
7091 regs = get_irq_regs();
7093 if (regs && !perf_exclude_event(event, regs)) {
7094 if (!(event->attr.exclude_idle && is_idle_task(current)))
7095 if (__perf_event_overflow(event, 1, &data, regs))
7096 ret = HRTIMER_NORESTART;
7099 period = max_t(u64, 10000, event->hw.sample_period);
7100 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7105 static void perf_swevent_start_hrtimer(struct perf_event *event)
7107 struct hw_perf_event *hwc = &event->hw;
7110 if (!is_sampling_event(event))
7113 period = local64_read(&hwc->period_left);
7118 local64_set(&hwc->period_left, 0);
7120 period = max_t(u64, 10000, hwc->sample_period);
7122 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7123 HRTIMER_MODE_REL_PINNED);
7126 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7128 struct hw_perf_event *hwc = &event->hw;
7130 if (is_sampling_event(event)) {
7131 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7132 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7134 hrtimer_cancel(&hwc->hrtimer);
7138 static void perf_swevent_init_hrtimer(struct perf_event *event)
7140 struct hw_perf_event *hwc = &event->hw;
7142 if (!is_sampling_event(event))
7145 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7146 hwc->hrtimer.function = perf_swevent_hrtimer;
7149 * Since hrtimers have a fixed rate, we can do a static freq->period
7150 * mapping and avoid the whole period adjust feedback stuff.
7152 if (event->attr.freq) {
7153 long freq = event->attr.sample_freq;
7155 event->attr.sample_period = NSEC_PER_SEC / freq;
7156 hwc->sample_period = event->attr.sample_period;
7157 local64_set(&hwc->period_left, hwc->sample_period);
7158 hwc->last_period = hwc->sample_period;
7159 event->attr.freq = 0;
7164 * Software event: cpu wall time clock
7167 static void cpu_clock_event_update(struct perf_event *event)
7172 now = local_clock();
7173 prev = local64_xchg(&event->hw.prev_count, now);
7174 local64_add(now - prev, &event->count);
7177 static void cpu_clock_event_start(struct perf_event *event, int flags)
7179 local64_set(&event->hw.prev_count, local_clock());
7180 perf_swevent_start_hrtimer(event);
7183 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7185 perf_swevent_cancel_hrtimer(event);
7186 cpu_clock_event_update(event);
7189 static int cpu_clock_event_add(struct perf_event *event, int flags)
7191 if (flags & PERF_EF_START)
7192 cpu_clock_event_start(event, flags);
7193 perf_event_update_userpage(event);
7198 static void cpu_clock_event_del(struct perf_event *event, int flags)
7200 cpu_clock_event_stop(event, flags);
7203 static void cpu_clock_event_read(struct perf_event *event)
7205 cpu_clock_event_update(event);
7208 static int cpu_clock_event_init(struct perf_event *event)
7210 if (event->attr.type != PERF_TYPE_SOFTWARE)
7213 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7217 * no branch sampling for software events
7219 if (has_branch_stack(event))
7222 perf_swevent_init_hrtimer(event);
7227 static struct pmu perf_cpu_clock = {
7228 .task_ctx_nr = perf_sw_context,
7230 .capabilities = PERF_PMU_CAP_NO_NMI,
7232 .event_init = cpu_clock_event_init,
7233 .add = cpu_clock_event_add,
7234 .del = cpu_clock_event_del,
7235 .start = cpu_clock_event_start,
7236 .stop = cpu_clock_event_stop,
7237 .read = cpu_clock_event_read,
7241 * Software event: task time clock
7244 static void task_clock_event_update(struct perf_event *event, u64 now)
7249 prev = local64_xchg(&event->hw.prev_count, now);
7251 local64_add(delta, &event->count);
7254 static void task_clock_event_start(struct perf_event *event, int flags)
7256 local64_set(&event->hw.prev_count, event->ctx->time);
7257 perf_swevent_start_hrtimer(event);
7260 static void task_clock_event_stop(struct perf_event *event, int flags)
7262 perf_swevent_cancel_hrtimer(event);
7263 task_clock_event_update(event, event->ctx->time);
7266 static int task_clock_event_add(struct perf_event *event, int flags)
7268 if (flags & PERF_EF_START)
7269 task_clock_event_start(event, flags);
7270 perf_event_update_userpage(event);
7275 static void task_clock_event_del(struct perf_event *event, int flags)
7277 task_clock_event_stop(event, PERF_EF_UPDATE);
7280 static void task_clock_event_read(struct perf_event *event)
7282 u64 now = perf_clock();
7283 u64 delta = now - event->ctx->timestamp;
7284 u64 time = event->ctx->time + delta;
7286 task_clock_event_update(event, time);
7289 static int task_clock_event_init(struct perf_event *event)
7291 if (event->attr.type != PERF_TYPE_SOFTWARE)
7294 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7298 * no branch sampling for software events
7300 if (has_branch_stack(event))
7303 perf_swevent_init_hrtimer(event);
7308 static struct pmu perf_task_clock = {
7309 .task_ctx_nr = perf_sw_context,
7311 .capabilities = PERF_PMU_CAP_NO_NMI,
7313 .event_init = task_clock_event_init,
7314 .add = task_clock_event_add,
7315 .del = task_clock_event_del,
7316 .start = task_clock_event_start,
7317 .stop = task_clock_event_stop,
7318 .read = task_clock_event_read,
7321 static void perf_pmu_nop_void(struct pmu *pmu)
7325 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7329 static int perf_pmu_nop_int(struct pmu *pmu)
7334 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7336 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7338 __this_cpu_write(nop_txn_flags, flags);
7340 if (flags & ~PERF_PMU_TXN_ADD)
7343 perf_pmu_disable(pmu);
7346 static int perf_pmu_commit_txn(struct pmu *pmu)
7348 unsigned int flags = __this_cpu_read(nop_txn_flags);
7350 __this_cpu_write(nop_txn_flags, 0);
7352 if (flags & ~PERF_PMU_TXN_ADD)
7355 perf_pmu_enable(pmu);
7359 static void perf_pmu_cancel_txn(struct pmu *pmu)
7361 unsigned int flags = __this_cpu_read(nop_txn_flags);
7363 __this_cpu_write(nop_txn_flags, 0);
7365 if (flags & ~PERF_PMU_TXN_ADD)
7368 perf_pmu_enable(pmu);
7371 static int perf_event_idx_default(struct perf_event *event)
7377 * Ensures all contexts with the same task_ctx_nr have the same
7378 * pmu_cpu_context too.
7380 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7387 list_for_each_entry(pmu, &pmus, entry) {
7388 if (pmu->task_ctx_nr == ctxn)
7389 return pmu->pmu_cpu_context;
7395 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7399 for_each_possible_cpu(cpu) {
7400 struct perf_cpu_context *cpuctx;
7402 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7404 if (cpuctx->unique_pmu == old_pmu)
7405 cpuctx->unique_pmu = pmu;
7409 static void free_pmu_context(struct pmu *pmu)
7413 mutex_lock(&pmus_lock);
7415 * Like a real lame refcount.
7417 list_for_each_entry(i, &pmus, entry) {
7418 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7419 update_pmu_context(i, pmu);
7424 free_percpu(pmu->pmu_cpu_context);
7426 mutex_unlock(&pmus_lock);
7428 static struct idr pmu_idr;
7431 type_show(struct device *dev, struct device_attribute *attr, char *page)
7433 struct pmu *pmu = dev_get_drvdata(dev);
7435 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7437 static DEVICE_ATTR_RO(type);
7440 perf_event_mux_interval_ms_show(struct device *dev,
7441 struct device_attribute *attr,
7444 struct pmu *pmu = dev_get_drvdata(dev);
7446 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7449 static DEFINE_MUTEX(mux_interval_mutex);
7452 perf_event_mux_interval_ms_store(struct device *dev,
7453 struct device_attribute *attr,
7454 const char *buf, size_t count)
7456 struct pmu *pmu = dev_get_drvdata(dev);
7457 int timer, cpu, ret;
7459 ret = kstrtoint(buf, 0, &timer);
7466 /* same value, noting to do */
7467 if (timer == pmu->hrtimer_interval_ms)
7470 mutex_lock(&mux_interval_mutex);
7471 pmu->hrtimer_interval_ms = timer;
7473 /* update all cpuctx for this PMU */
7475 for_each_online_cpu(cpu) {
7476 struct perf_cpu_context *cpuctx;
7477 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7478 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7480 cpu_function_call(cpu,
7481 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7484 mutex_unlock(&mux_interval_mutex);
7488 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7490 static struct attribute *pmu_dev_attrs[] = {
7491 &dev_attr_type.attr,
7492 &dev_attr_perf_event_mux_interval_ms.attr,
7495 ATTRIBUTE_GROUPS(pmu_dev);
7497 static int pmu_bus_running;
7498 static struct bus_type pmu_bus = {
7499 .name = "event_source",
7500 .dev_groups = pmu_dev_groups,
7503 static void pmu_dev_release(struct device *dev)
7508 static int pmu_dev_alloc(struct pmu *pmu)
7512 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7516 pmu->dev->groups = pmu->attr_groups;
7517 device_initialize(pmu->dev);
7518 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7522 dev_set_drvdata(pmu->dev, pmu);
7523 pmu->dev->bus = &pmu_bus;
7524 pmu->dev->release = pmu_dev_release;
7525 ret = device_add(pmu->dev);
7533 put_device(pmu->dev);
7537 static struct lock_class_key cpuctx_mutex;
7538 static struct lock_class_key cpuctx_lock;
7540 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7544 mutex_lock(&pmus_lock);
7546 pmu->pmu_disable_count = alloc_percpu(int);
7547 if (!pmu->pmu_disable_count)
7556 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7564 if (pmu_bus_running) {
7565 ret = pmu_dev_alloc(pmu);
7571 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7572 if (pmu->pmu_cpu_context)
7573 goto got_cpu_context;
7576 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7577 if (!pmu->pmu_cpu_context)
7580 for_each_possible_cpu(cpu) {
7581 struct perf_cpu_context *cpuctx;
7583 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7584 __perf_event_init_context(&cpuctx->ctx);
7585 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7586 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7587 cpuctx->ctx.pmu = pmu;
7589 __perf_mux_hrtimer_init(cpuctx, cpu);
7591 cpuctx->unique_pmu = pmu;
7595 if (!pmu->start_txn) {
7596 if (pmu->pmu_enable) {
7598 * If we have pmu_enable/pmu_disable calls, install
7599 * transaction stubs that use that to try and batch
7600 * hardware accesses.
7602 pmu->start_txn = perf_pmu_start_txn;
7603 pmu->commit_txn = perf_pmu_commit_txn;
7604 pmu->cancel_txn = perf_pmu_cancel_txn;
7606 pmu->start_txn = perf_pmu_nop_txn;
7607 pmu->commit_txn = perf_pmu_nop_int;
7608 pmu->cancel_txn = perf_pmu_nop_void;
7612 if (!pmu->pmu_enable) {
7613 pmu->pmu_enable = perf_pmu_nop_void;
7614 pmu->pmu_disable = perf_pmu_nop_void;
7617 if (!pmu->event_idx)
7618 pmu->event_idx = perf_event_idx_default;
7620 list_add_rcu(&pmu->entry, &pmus);
7621 atomic_set(&pmu->exclusive_cnt, 0);
7624 mutex_unlock(&pmus_lock);
7629 device_del(pmu->dev);
7630 put_device(pmu->dev);
7633 if (pmu->type >= PERF_TYPE_MAX)
7634 idr_remove(&pmu_idr, pmu->type);
7637 free_percpu(pmu->pmu_disable_count);
7640 EXPORT_SYMBOL_GPL(perf_pmu_register);
7642 void perf_pmu_unregister(struct pmu *pmu)
7644 mutex_lock(&pmus_lock);
7645 list_del_rcu(&pmu->entry);
7646 mutex_unlock(&pmus_lock);
7649 * We dereference the pmu list under both SRCU and regular RCU, so
7650 * synchronize against both of those.
7652 synchronize_srcu(&pmus_srcu);
7655 free_percpu(pmu->pmu_disable_count);
7656 if (pmu->type >= PERF_TYPE_MAX)
7657 idr_remove(&pmu_idr, pmu->type);
7658 device_del(pmu->dev);
7659 put_device(pmu->dev);
7660 free_pmu_context(pmu);
7662 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7664 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7666 struct perf_event_context *ctx = NULL;
7669 if (!try_module_get(pmu->module))
7672 if (event->group_leader != event) {
7674 * This ctx->mutex can nest when we're called through
7675 * inheritance. See the perf_event_ctx_lock_nested() comment.
7677 ctx = perf_event_ctx_lock_nested(event->group_leader,
7678 SINGLE_DEPTH_NESTING);
7683 ret = pmu->event_init(event);
7686 perf_event_ctx_unlock(event->group_leader, ctx);
7689 module_put(pmu->module);
7694 static struct pmu *perf_init_event(struct perf_event *event)
7696 struct pmu *pmu = NULL;
7700 idx = srcu_read_lock(&pmus_srcu);
7703 pmu = idr_find(&pmu_idr, event->attr.type);
7706 ret = perf_try_init_event(pmu, event);
7712 list_for_each_entry_rcu(pmu, &pmus, entry) {
7713 ret = perf_try_init_event(pmu, event);
7717 if (ret != -ENOENT) {
7722 pmu = ERR_PTR(-ENOENT);
7724 srcu_read_unlock(&pmus_srcu, idx);
7729 static void account_event_cpu(struct perf_event *event, int cpu)
7734 if (is_cgroup_event(event))
7735 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7738 static void account_event(struct perf_event *event)
7745 if (event->attach_state & PERF_ATTACH_TASK)
7747 if (event->attr.mmap || event->attr.mmap_data)
7748 atomic_inc(&nr_mmap_events);
7749 if (event->attr.comm)
7750 atomic_inc(&nr_comm_events);
7751 if (event->attr.task)
7752 atomic_inc(&nr_task_events);
7753 if (event->attr.freq) {
7754 if (atomic_inc_return(&nr_freq_events) == 1)
7755 tick_nohz_full_kick_all();
7757 if (event->attr.context_switch) {
7758 atomic_inc(&nr_switch_events);
7761 if (has_branch_stack(event))
7763 if (is_cgroup_event(event))
7767 static_key_slow_inc(&perf_sched_events.key);
7769 account_event_cpu(event, event->cpu);
7773 * Allocate and initialize a event structure
7775 static struct perf_event *
7776 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7777 struct task_struct *task,
7778 struct perf_event *group_leader,
7779 struct perf_event *parent_event,
7780 perf_overflow_handler_t overflow_handler,
7781 void *context, int cgroup_fd)
7784 struct perf_event *event;
7785 struct hw_perf_event *hwc;
7788 if ((unsigned)cpu >= nr_cpu_ids) {
7789 if (!task || cpu != -1)
7790 return ERR_PTR(-EINVAL);
7793 event = kzalloc(sizeof(*event), GFP_KERNEL);
7795 return ERR_PTR(-ENOMEM);
7798 * Single events are their own group leaders, with an
7799 * empty sibling list:
7802 group_leader = event;
7804 mutex_init(&event->child_mutex);
7805 INIT_LIST_HEAD(&event->child_list);
7807 INIT_LIST_HEAD(&event->group_entry);
7808 INIT_LIST_HEAD(&event->event_entry);
7809 INIT_LIST_HEAD(&event->sibling_list);
7810 INIT_LIST_HEAD(&event->rb_entry);
7811 INIT_LIST_HEAD(&event->active_entry);
7812 INIT_HLIST_NODE(&event->hlist_entry);
7815 init_waitqueue_head(&event->waitq);
7816 init_irq_work(&event->pending, perf_pending_event);
7818 mutex_init(&event->mmap_mutex);
7820 atomic_long_set(&event->refcount, 1);
7822 event->attr = *attr;
7823 event->group_leader = group_leader;
7827 event->parent = parent_event;
7829 event->ns = get_pid_ns(task_active_pid_ns(current));
7830 event->id = atomic64_inc_return(&perf_event_id);
7832 event->state = PERF_EVENT_STATE_INACTIVE;
7835 event->attach_state = PERF_ATTACH_TASK;
7837 * XXX pmu::event_init needs to know what task to account to
7838 * and we cannot use the ctx information because we need the
7839 * pmu before we get a ctx.
7841 event->hw.target = task;
7844 event->clock = &local_clock;
7846 event->clock = parent_event->clock;
7848 if (!overflow_handler && parent_event) {
7849 overflow_handler = parent_event->overflow_handler;
7850 context = parent_event->overflow_handler_context;
7853 event->overflow_handler = overflow_handler;
7854 event->overflow_handler_context = context;
7856 perf_event__state_init(event);
7861 hwc->sample_period = attr->sample_period;
7862 if (attr->freq && attr->sample_freq)
7863 hwc->sample_period = 1;
7864 hwc->last_period = hwc->sample_period;
7866 local64_set(&hwc->period_left, hwc->sample_period);
7869 * we currently do not support PERF_FORMAT_GROUP on inherited events
7871 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7874 if (!has_branch_stack(event))
7875 event->attr.branch_sample_type = 0;
7877 if (cgroup_fd != -1) {
7878 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7883 pmu = perf_init_event(event);
7886 else if (IS_ERR(pmu)) {
7891 err = exclusive_event_init(event);
7895 if (!event->parent) {
7896 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7897 err = get_callchain_buffers();
7906 exclusive_event_destroy(event);
7910 event->destroy(event);
7911 module_put(pmu->module);
7913 if (is_cgroup_event(event))
7914 perf_detach_cgroup(event);
7916 put_pid_ns(event->ns);
7919 return ERR_PTR(err);
7922 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7923 struct perf_event_attr *attr)
7928 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7932 * zero the full structure, so that a short copy will be nice.
7934 memset(attr, 0, sizeof(*attr));
7936 ret = get_user(size, &uattr->size);
7940 if (size > PAGE_SIZE) /* silly large */
7943 if (!size) /* abi compat */
7944 size = PERF_ATTR_SIZE_VER0;
7946 if (size < PERF_ATTR_SIZE_VER0)
7950 * If we're handed a bigger struct than we know of,
7951 * ensure all the unknown bits are 0 - i.e. new
7952 * user-space does not rely on any kernel feature
7953 * extensions we dont know about yet.
7955 if (size > sizeof(*attr)) {
7956 unsigned char __user *addr;
7957 unsigned char __user *end;
7960 addr = (void __user *)uattr + sizeof(*attr);
7961 end = (void __user *)uattr + size;
7963 for (; addr < end; addr++) {
7964 ret = get_user(val, addr);
7970 size = sizeof(*attr);
7973 ret = copy_from_user(attr, uattr, size);
7977 if (attr->__reserved_1)
7980 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
7983 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
7986 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
7987 u64 mask = attr->branch_sample_type;
7989 /* only using defined bits */
7990 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
7993 /* at least one branch bit must be set */
7994 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
7997 /* propagate priv level, when not set for branch */
7998 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8000 /* exclude_kernel checked on syscall entry */
8001 if (!attr->exclude_kernel)
8002 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8004 if (!attr->exclude_user)
8005 mask |= PERF_SAMPLE_BRANCH_USER;
8007 if (!attr->exclude_hv)
8008 mask |= PERF_SAMPLE_BRANCH_HV;
8010 * adjust user setting (for HW filter setup)
8012 attr->branch_sample_type = mask;
8014 /* privileged levels capture (kernel, hv): check permissions */
8015 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8016 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8020 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8021 ret = perf_reg_validate(attr->sample_regs_user);
8026 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8027 if (!arch_perf_have_user_stack_dump())
8031 * We have __u32 type for the size, but so far
8032 * we can only use __u16 as maximum due to the
8033 * __u16 sample size limit.
8035 if (attr->sample_stack_user >= USHRT_MAX)
8037 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8041 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8042 ret = perf_reg_validate(attr->sample_regs_intr);
8047 put_user(sizeof(*attr), &uattr->size);
8053 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8055 struct ring_buffer *rb = NULL;
8061 /* don't allow circular references */
8062 if (event == output_event)
8066 * Don't allow cross-cpu buffers
8068 if (output_event->cpu != event->cpu)
8072 * If its not a per-cpu rb, it must be the same task.
8074 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8078 * Mixing clocks in the same buffer is trouble you don't need.
8080 if (output_event->clock != event->clock)
8084 * If both events generate aux data, they must be on the same PMU
8086 if (has_aux(event) && has_aux(output_event) &&
8087 event->pmu != output_event->pmu)
8091 mutex_lock(&event->mmap_mutex);
8092 /* Can't redirect output if we've got an active mmap() */
8093 if (atomic_read(&event->mmap_count))
8097 /* get the rb we want to redirect to */
8098 rb = ring_buffer_get(output_event);
8103 ring_buffer_attach(event, rb);
8107 mutex_unlock(&event->mmap_mutex);
8113 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8119 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8122 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8124 bool nmi_safe = false;
8127 case CLOCK_MONOTONIC:
8128 event->clock = &ktime_get_mono_fast_ns;
8132 case CLOCK_MONOTONIC_RAW:
8133 event->clock = &ktime_get_raw_fast_ns;
8137 case CLOCK_REALTIME:
8138 event->clock = &ktime_get_real_ns;
8141 case CLOCK_BOOTTIME:
8142 event->clock = &ktime_get_boot_ns;
8146 event->clock = &ktime_get_tai_ns;
8153 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8160 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8162 * @attr_uptr: event_id type attributes for monitoring/sampling
8165 * @group_fd: group leader event fd
8167 SYSCALL_DEFINE5(perf_event_open,
8168 struct perf_event_attr __user *, attr_uptr,
8169 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8171 struct perf_event *group_leader = NULL, *output_event = NULL;
8172 struct perf_event *event, *sibling;
8173 struct perf_event_attr attr;
8174 struct perf_event_context *ctx, *uninitialized_var(gctx);
8175 struct file *event_file = NULL;
8176 struct fd group = {NULL, 0};
8177 struct task_struct *task = NULL;
8182 int f_flags = O_RDWR;
8185 /* for future expandability... */
8186 if (flags & ~PERF_FLAG_ALL)
8189 err = perf_copy_attr(attr_uptr, &attr);
8193 if (!attr.exclude_kernel) {
8194 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8199 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8202 if (attr.sample_period & (1ULL << 63))
8207 * In cgroup mode, the pid argument is used to pass the fd
8208 * opened to the cgroup directory in cgroupfs. The cpu argument
8209 * designates the cpu on which to monitor threads from that
8212 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8215 if (flags & PERF_FLAG_FD_CLOEXEC)
8216 f_flags |= O_CLOEXEC;
8218 event_fd = get_unused_fd_flags(f_flags);
8222 if (group_fd != -1) {
8223 err = perf_fget_light(group_fd, &group);
8226 group_leader = group.file->private_data;
8227 if (flags & PERF_FLAG_FD_OUTPUT)
8228 output_event = group_leader;
8229 if (flags & PERF_FLAG_FD_NO_GROUP)
8230 group_leader = NULL;
8233 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8234 task = find_lively_task_by_vpid(pid);
8236 err = PTR_ERR(task);
8241 if (task && group_leader &&
8242 group_leader->attr.inherit != attr.inherit) {
8249 if (flags & PERF_FLAG_PID_CGROUP)
8252 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8253 NULL, NULL, cgroup_fd);
8254 if (IS_ERR(event)) {
8255 err = PTR_ERR(event);
8259 if (is_sampling_event(event)) {
8260 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8266 account_event(event);
8269 * Special case software events and allow them to be part of
8270 * any hardware group.
8274 if (attr.use_clockid) {
8275 err = perf_event_set_clock(event, attr.clockid);
8281 (is_software_event(event) != is_software_event(group_leader))) {
8282 if (is_software_event(event)) {
8284 * If event and group_leader are not both a software
8285 * event, and event is, then group leader is not.
8287 * Allow the addition of software events to !software
8288 * groups, this is safe because software events never
8291 pmu = group_leader->pmu;
8292 } else if (is_software_event(group_leader) &&
8293 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8295 * In case the group is a pure software group, and we
8296 * try to add a hardware event, move the whole group to
8297 * the hardware context.
8304 * Get the target context (task or percpu):
8306 ctx = find_get_context(pmu, task, event);
8312 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8318 put_task_struct(task);
8323 * Look up the group leader (we will attach this event to it):
8329 * Do not allow a recursive hierarchy (this new sibling
8330 * becoming part of another group-sibling):
8332 if (group_leader->group_leader != group_leader)
8335 /* All events in a group should have the same clock */
8336 if (group_leader->clock != event->clock)
8340 * Do not allow to attach to a group in a different
8341 * task or CPU context:
8345 * Make sure we're both on the same task, or both
8348 if (group_leader->ctx->task != ctx->task)
8352 * Make sure we're both events for the same CPU;
8353 * grouping events for different CPUs is broken; since
8354 * you can never concurrently schedule them anyhow.
8356 if (group_leader->cpu != event->cpu)
8359 if (group_leader->ctx != ctx)
8364 * Only a group leader can be exclusive or pinned
8366 if (attr.exclusive || attr.pinned)
8371 err = perf_event_set_output(event, output_event);
8376 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8378 if (IS_ERR(event_file)) {
8379 err = PTR_ERR(event_file);
8384 gctx = group_leader->ctx;
8385 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8387 mutex_lock(&ctx->mutex);
8390 if (!perf_event_validate_size(event)) {
8396 * Must be under the same ctx::mutex as perf_install_in_context(),
8397 * because we need to serialize with concurrent event creation.
8399 if (!exclusive_event_installable(event, ctx)) {
8400 /* exclusive and group stuff are assumed mutually exclusive */
8401 WARN_ON_ONCE(move_group);
8407 WARN_ON_ONCE(ctx->parent_ctx);
8411 * See perf_event_ctx_lock() for comments on the details
8412 * of swizzling perf_event::ctx.
8414 perf_remove_from_context(group_leader, false);
8416 list_for_each_entry(sibling, &group_leader->sibling_list,
8418 perf_remove_from_context(sibling, false);
8423 * Wait for everybody to stop referencing the events through
8424 * the old lists, before installing it on new lists.
8429 * Install the group siblings before the group leader.
8431 * Because a group leader will try and install the entire group
8432 * (through the sibling list, which is still in-tact), we can
8433 * end up with siblings installed in the wrong context.
8435 * By installing siblings first we NO-OP because they're not
8436 * reachable through the group lists.
8438 list_for_each_entry(sibling, &group_leader->sibling_list,
8440 perf_event__state_init(sibling);
8441 perf_install_in_context(ctx, sibling, sibling->cpu);
8446 * Removing from the context ends up with disabled
8447 * event. What we want here is event in the initial
8448 * startup state, ready to be add into new context.
8450 perf_event__state_init(group_leader);
8451 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8455 * Now that all events are installed in @ctx, nothing
8456 * references @gctx anymore, so drop the last reference we have
8463 * Precalculate sample_data sizes; do while holding ctx::mutex such
8464 * that we're serialized against further additions and before
8465 * perf_install_in_context() which is the point the event is active and
8466 * can use these values.
8468 perf_event__header_size(event);
8469 perf_event__id_header_size(event);
8471 perf_install_in_context(ctx, event, event->cpu);
8472 perf_unpin_context(ctx);
8475 mutex_unlock(&gctx->mutex);
8476 mutex_unlock(&ctx->mutex);
8480 event->owner = current;
8482 mutex_lock(¤t->perf_event_mutex);
8483 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8484 mutex_unlock(¤t->perf_event_mutex);
8487 * Drop the reference on the group_event after placing the
8488 * new event on the sibling_list. This ensures destruction
8489 * of the group leader will find the pointer to itself in
8490 * perf_group_detach().
8493 fd_install(event_fd, event_file);
8498 mutex_unlock(&gctx->mutex);
8499 mutex_unlock(&ctx->mutex);
8503 perf_unpin_context(ctx);
8511 put_task_struct(task);
8515 put_unused_fd(event_fd);
8520 * perf_event_create_kernel_counter
8522 * @attr: attributes of the counter to create
8523 * @cpu: cpu in which the counter is bound
8524 * @task: task to profile (NULL for percpu)
8527 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8528 struct task_struct *task,
8529 perf_overflow_handler_t overflow_handler,
8532 struct perf_event_context *ctx;
8533 struct perf_event *event;
8537 * Get the target context (task or percpu):
8540 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8541 overflow_handler, context, -1);
8542 if (IS_ERR(event)) {
8543 err = PTR_ERR(event);
8547 /* Mark owner so we could distinguish it from user events. */
8548 event->owner = EVENT_OWNER_KERNEL;
8550 account_event(event);
8552 ctx = find_get_context(event->pmu, task, event);
8558 WARN_ON_ONCE(ctx->parent_ctx);
8559 mutex_lock(&ctx->mutex);
8560 if (!exclusive_event_installable(event, ctx)) {
8561 mutex_unlock(&ctx->mutex);
8562 perf_unpin_context(ctx);
8568 perf_install_in_context(ctx, event, cpu);
8569 perf_unpin_context(ctx);
8570 mutex_unlock(&ctx->mutex);
8577 return ERR_PTR(err);
8579 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8581 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8583 struct perf_event_context *src_ctx;
8584 struct perf_event_context *dst_ctx;
8585 struct perf_event *event, *tmp;
8588 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8589 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8592 * See perf_event_ctx_lock() for comments on the details
8593 * of swizzling perf_event::ctx.
8595 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8596 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8598 perf_remove_from_context(event, false);
8599 unaccount_event_cpu(event, src_cpu);
8601 list_add(&event->migrate_entry, &events);
8605 * Wait for the events to quiesce before re-instating them.
8610 * Re-instate events in 2 passes.
8612 * Skip over group leaders and only install siblings on this first
8613 * pass, siblings will not get enabled without a leader, however a
8614 * leader will enable its siblings, even if those are still on the old
8617 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8618 if (event->group_leader == event)
8621 list_del(&event->migrate_entry);
8622 if (event->state >= PERF_EVENT_STATE_OFF)
8623 event->state = PERF_EVENT_STATE_INACTIVE;
8624 account_event_cpu(event, dst_cpu);
8625 perf_install_in_context(dst_ctx, event, dst_cpu);
8630 * Once all the siblings are setup properly, install the group leaders
8633 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8634 list_del(&event->migrate_entry);
8635 if (event->state >= PERF_EVENT_STATE_OFF)
8636 event->state = PERF_EVENT_STATE_INACTIVE;
8637 account_event_cpu(event, dst_cpu);
8638 perf_install_in_context(dst_ctx, event, dst_cpu);
8641 mutex_unlock(&dst_ctx->mutex);
8642 mutex_unlock(&src_ctx->mutex);
8644 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8646 static void sync_child_event(struct perf_event *child_event,
8647 struct task_struct *child)
8649 struct perf_event *parent_event = child_event->parent;
8652 if (child_event->attr.inherit_stat)
8653 perf_event_read_event(child_event, child);
8655 child_val = perf_event_count(child_event);
8658 * Add back the child's count to the parent's count:
8660 atomic64_add(child_val, &parent_event->child_count);
8661 atomic64_add(child_event->total_time_enabled,
8662 &parent_event->child_total_time_enabled);
8663 atomic64_add(child_event->total_time_running,
8664 &parent_event->child_total_time_running);
8667 * Remove this event from the parent's list
8669 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8670 mutex_lock(&parent_event->child_mutex);
8671 list_del_init(&child_event->child_list);
8672 mutex_unlock(&parent_event->child_mutex);
8675 * Make sure user/parent get notified, that we just
8678 perf_event_wakeup(parent_event);
8681 * Release the parent event, if this was the last
8684 put_event(parent_event);
8688 __perf_event_exit_task(struct perf_event *child_event,
8689 struct perf_event_context *child_ctx,
8690 struct task_struct *child)
8693 * Do not destroy the 'original' grouping; because of the context
8694 * switch optimization the original events could've ended up in a
8695 * random child task.
8697 * If we were to destroy the original group, all group related
8698 * operations would cease to function properly after this random
8701 * Do destroy all inherited groups, we don't care about those
8702 * and being thorough is better.
8704 raw_spin_lock_irq(&child_ctx->lock);
8705 WARN_ON_ONCE(child_ctx->is_active);
8707 if (!!child_event->parent)
8708 perf_group_detach(child_event);
8709 list_del_event(child_event, child_ctx);
8710 raw_spin_unlock_irq(&child_ctx->lock);
8713 * It can happen that the parent exits first, and has events
8714 * that are still around due to the child reference. These
8715 * events need to be zapped.
8717 if (child_event->parent) {
8718 sync_child_event(child_event, child);
8719 free_event(child_event);
8721 child_event->state = PERF_EVENT_STATE_EXIT;
8722 perf_event_wakeup(child_event);
8726 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8728 struct perf_event *child_event, *next;
8729 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8731 if (likely(!child->perf_event_ctxp[ctxn]))
8734 local_irq_disable();
8735 WARN_ON_ONCE(child != current);
8737 * We can't reschedule here because interrupts are disabled,
8738 * and child must be current.
8740 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8743 * Take the context lock here so that if find_get_context is
8744 * reading child->perf_event_ctxp, we wait until it has
8745 * incremented the context's refcount before we do put_ctx below.
8747 raw_spin_lock(&child_ctx->lock);
8748 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
8749 child->perf_event_ctxp[ctxn] = NULL;
8752 * If this context is a clone; unclone it so it can't get
8753 * swapped to another process while we're removing all
8754 * the events from it.
8756 clone_ctx = unclone_ctx(child_ctx);
8757 update_context_time(child_ctx);
8758 raw_spin_unlock_irq(&child_ctx->lock);
8764 * Report the task dead after unscheduling the events so that we
8765 * won't get any samples after PERF_RECORD_EXIT. We can however still
8766 * get a few PERF_RECORD_READ events.
8768 perf_event_task(child, child_ctx, 0);
8771 * We can recurse on the same lock type through:
8773 * __perf_event_exit_task()
8774 * sync_child_event()
8776 * mutex_lock(&ctx->mutex)
8778 * But since its the parent context it won't be the same instance.
8780 mutex_lock(&child_ctx->mutex);
8782 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8783 __perf_event_exit_task(child_event, child_ctx, child);
8785 mutex_unlock(&child_ctx->mutex);
8791 * When a child task exits, feed back event values to parent events.
8793 void perf_event_exit_task(struct task_struct *child)
8795 struct perf_event *event, *tmp;
8798 mutex_lock(&child->perf_event_mutex);
8799 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8801 list_del_init(&event->owner_entry);
8804 * Ensure the list deletion is visible before we clear
8805 * the owner, closes a race against perf_release() where
8806 * we need to serialize on the owner->perf_event_mutex.
8809 event->owner = NULL;
8811 mutex_unlock(&child->perf_event_mutex);
8813 for_each_task_context_nr(ctxn)
8814 perf_event_exit_task_context(child, ctxn);
8817 * The perf_event_exit_task_context calls perf_event_task
8818 * with child's task_ctx, which generates EXIT events for
8819 * child contexts and sets child->perf_event_ctxp[] to NULL.
8820 * At this point we need to send EXIT events to cpu contexts.
8822 perf_event_task(child, NULL, 0);
8825 static void perf_free_event(struct perf_event *event,
8826 struct perf_event_context *ctx)
8828 struct perf_event *parent = event->parent;
8830 if (WARN_ON_ONCE(!parent))
8833 mutex_lock(&parent->child_mutex);
8834 list_del_init(&event->child_list);
8835 mutex_unlock(&parent->child_mutex);
8839 raw_spin_lock_irq(&ctx->lock);
8840 perf_group_detach(event);
8841 list_del_event(event, ctx);
8842 raw_spin_unlock_irq(&ctx->lock);
8847 * Free an unexposed, unused context as created by inheritance by
8848 * perf_event_init_task below, used by fork() in case of fail.
8850 * Not all locks are strictly required, but take them anyway to be nice and
8851 * help out with the lockdep assertions.
8853 void perf_event_free_task(struct task_struct *task)
8855 struct perf_event_context *ctx;
8856 struct perf_event *event, *tmp;
8859 for_each_task_context_nr(ctxn) {
8860 ctx = task->perf_event_ctxp[ctxn];
8864 mutex_lock(&ctx->mutex);
8866 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8868 perf_free_event(event, ctx);
8870 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8872 perf_free_event(event, ctx);
8874 if (!list_empty(&ctx->pinned_groups) ||
8875 !list_empty(&ctx->flexible_groups))
8878 mutex_unlock(&ctx->mutex);
8884 void perf_event_delayed_put(struct task_struct *task)
8888 for_each_task_context_nr(ctxn)
8889 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8892 struct perf_event *perf_event_get(unsigned int fd)
8896 struct perf_event *event;
8898 err = perf_fget_light(fd, &f);
8900 return ERR_PTR(err);
8902 event = f.file->private_data;
8903 atomic_long_inc(&event->refcount);
8909 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8912 return ERR_PTR(-EINVAL);
8914 return &event->attr;
8918 * inherit a event from parent task to child task:
8920 static struct perf_event *
8921 inherit_event(struct perf_event *parent_event,
8922 struct task_struct *parent,
8923 struct perf_event_context *parent_ctx,
8924 struct task_struct *child,
8925 struct perf_event *group_leader,
8926 struct perf_event_context *child_ctx)
8928 enum perf_event_active_state parent_state = parent_event->state;
8929 struct perf_event *child_event;
8930 unsigned long flags;
8933 * Instead of creating recursive hierarchies of events,
8934 * we link inherited events back to the original parent,
8935 * which has a filp for sure, which we use as the reference
8938 if (parent_event->parent)
8939 parent_event = parent_event->parent;
8941 child_event = perf_event_alloc(&parent_event->attr,
8944 group_leader, parent_event,
8946 if (IS_ERR(child_event))
8949 if (is_orphaned_event(parent_event) ||
8950 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8951 free_event(child_event);
8958 * Make the child state follow the state of the parent event,
8959 * not its attr.disabled bit. We hold the parent's mutex,
8960 * so we won't race with perf_event_{en, dis}able_family.
8962 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
8963 child_event->state = PERF_EVENT_STATE_INACTIVE;
8965 child_event->state = PERF_EVENT_STATE_OFF;
8967 if (parent_event->attr.freq) {
8968 u64 sample_period = parent_event->hw.sample_period;
8969 struct hw_perf_event *hwc = &child_event->hw;
8971 hwc->sample_period = sample_period;
8972 hwc->last_period = sample_period;
8974 local64_set(&hwc->period_left, sample_period);
8977 child_event->ctx = child_ctx;
8978 child_event->overflow_handler = parent_event->overflow_handler;
8979 child_event->overflow_handler_context
8980 = parent_event->overflow_handler_context;
8983 * Precalculate sample_data sizes
8985 perf_event__header_size(child_event);
8986 perf_event__id_header_size(child_event);
8989 * Link it up in the child's context:
8991 raw_spin_lock_irqsave(&child_ctx->lock, flags);
8992 add_event_to_ctx(child_event, child_ctx);
8993 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8996 * Link this into the parent event's child list
8998 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8999 mutex_lock(&parent_event->child_mutex);
9000 list_add_tail(&child_event->child_list, &parent_event->child_list);
9001 mutex_unlock(&parent_event->child_mutex);
9006 static int inherit_group(struct perf_event *parent_event,
9007 struct task_struct *parent,
9008 struct perf_event_context *parent_ctx,
9009 struct task_struct *child,
9010 struct perf_event_context *child_ctx)
9012 struct perf_event *leader;
9013 struct perf_event *sub;
9014 struct perf_event *child_ctr;
9016 leader = inherit_event(parent_event, parent, parent_ctx,
9017 child, NULL, child_ctx);
9019 return PTR_ERR(leader);
9020 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9021 child_ctr = inherit_event(sub, parent, parent_ctx,
9022 child, leader, child_ctx);
9023 if (IS_ERR(child_ctr))
9024 return PTR_ERR(child_ctr);
9030 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9031 struct perf_event_context *parent_ctx,
9032 struct task_struct *child, int ctxn,
9036 struct perf_event_context *child_ctx;
9038 if (!event->attr.inherit) {
9043 child_ctx = child->perf_event_ctxp[ctxn];
9046 * This is executed from the parent task context, so
9047 * inherit events that have been marked for cloning.
9048 * First allocate and initialize a context for the
9052 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9056 child->perf_event_ctxp[ctxn] = child_ctx;
9059 ret = inherit_group(event, parent, parent_ctx,
9069 * Initialize the perf_event context in task_struct
9071 static int perf_event_init_context(struct task_struct *child, int ctxn)
9073 struct perf_event_context *child_ctx, *parent_ctx;
9074 struct perf_event_context *cloned_ctx;
9075 struct perf_event *event;
9076 struct task_struct *parent = current;
9077 int inherited_all = 1;
9078 unsigned long flags;
9081 if (likely(!parent->perf_event_ctxp[ctxn]))
9085 * If the parent's context is a clone, pin it so it won't get
9088 parent_ctx = perf_pin_task_context(parent, ctxn);
9093 * No need to check if parent_ctx != NULL here; since we saw
9094 * it non-NULL earlier, the only reason for it to become NULL
9095 * is if we exit, and since we're currently in the middle of
9096 * a fork we can't be exiting at the same time.
9100 * Lock the parent list. No need to lock the child - not PID
9101 * hashed yet and not running, so nobody can access it.
9103 mutex_lock(&parent_ctx->mutex);
9106 * We dont have to disable NMIs - we are only looking at
9107 * the list, not manipulating it:
9109 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9110 ret = inherit_task_group(event, parent, parent_ctx,
9111 child, ctxn, &inherited_all);
9117 * We can't hold ctx->lock when iterating the ->flexible_group list due
9118 * to allocations, but we need to prevent rotation because
9119 * rotate_ctx() will change the list from interrupt context.
9121 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9122 parent_ctx->rotate_disable = 1;
9123 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9125 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9126 ret = inherit_task_group(event, parent, parent_ctx,
9127 child, ctxn, &inherited_all);
9132 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9133 parent_ctx->rotate_disable = 0;
9135 child_ctx = child->perf_event_ctxp[ctxn];
9137 if (child_ctx && inherited_all) {
9139 * Mark the child context as a clone of the parent
9140 * context, or of whatever the parent is a clone of.
9142 * Note that if the parent is a clone, the holding of
9143 * parent_ctx->lock avoids it from being uncloned.
9145 cloned_ctx = parent_ctx->parent_ctx;
9147 child_ctx->parent_ctx = cloned_ctx;
9148 child_ctx->parent_gen = parent_ctx->parent_gen;
9150 child_ctx->parent_ctx = parent_ctx;
9151 child_ctx->parent_gen = parent_ctx->generation;
9153 get_ctx(child_ctx->parent_ctx);
9156 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9157 mutex_unlock(&parent_ctx->mutex);
9159 perf_unpin_context(parent_ctx);
9160 put_ctx(parent_ctx);
9166 * Initialize the perf_event context in task_struct
9168 int perf_event_init_task(struct task_struct *child)
9172 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9173 mutex_init(&child->perf_event_mutex);
9174 INIT_LIST_HEAD(&child->perf_event_list);
9176 for_each_task_context_nr(ctxn) {
9177 ret = perf_event_init_context(child, ctxn);
9179 perf_event_free_task(child);
9187 static void __init perf_event_init_all_cpus(void)
9189 struct swevent_htable *swhash;
9192 for_each_possible_cpu(cpu) {
9193 swhash = &per_cpu(swevent_htable, cpu);
9194 mutex_init(&swhash->hlist_mutex);
9195 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9199 static void perf_event_init_cpu(int cpu)
9201 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9203 mutex_lock(&swhash->hlist_mutex);
9204 if (swhash->hlist_refcount > 0) {
9205 struct swevent_hlist *hlist;
9207 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9209 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9211 mutex_unlock(&swhash->hlist_mutex);
9214 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9215 static void __perf_event_exit_context(void *__info)
9217 struct perf_event_context *ctx = __info;
9218 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
9219 struct perf_event *event;
9221 raw_spin_lock(&ctx->lock);
9222 list_for_each_entry(event, &ctx->event_list, event_entry)
9223 __perf_remove_from_context(event, cpuctx, ctx, (void *)(unsigned long)true);
9224 raw_spin_unlock(&ctx->lock);
9227 static void perf_event_exit_cpu_context(int cpu)
9229 struct perf_event_context *ctx;
9233 idx = srcu_read_lock(&pmus_srcu);
9234 list_for_each_entry_rcu(pmu, &pmus, entry) {
9235 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9237 mutex_lock(&ctx->mutex);
9238 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9239 mutex_unlock(&ctx->mutex);
9241 srcu_read_unlock(&pmus_srcu, idx);
9244 static void perf_event_exit_cpu(int cpu)
9246 perf_event_exit_cpu_context(cpu);
9249 static inline void perf_event_exit_cpu(int cpu) { }
9253 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9257 for_each_online_cpu(cpu)
9258 perf_event_exit_cpu(cpu);
9264 * Run the perf reboot notifier at the very last possible moment so that
9265 * the generic watchdog code runs as long as possible.
9267 static struct notifier_block perf_reboot_notifier = {
9268 .notifier_call = perf_reboot,
9269 .priority = INT_MIN,
9273 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9275 unsigned int cpu = (long)hcpu;
9277 switch (action & ~CPU_TASKS_FROZEN) {
9279 case CPU_UP_PREPARE:
9280 case CPU_DOWN_FAILED:
9281 perf_event_init_cpu(cpu);
9284 case CPU_UP_CANCELED:
9285 case CPU_DOWN_PREPARE:
9286 perf_event_exit_cpu(cpu);
9295 void __init perf_event_init(void)
9301 perf_event_init_all_cpus();
9302 init_srcu_struct(&pmus_srcu);
9303 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9304 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9305 perf_pmu_register(&perf_task_clock, NULL, -1);
9307 perf_cpu_notifier(perf_cpu_notify);
9308 register_reboot_notifier(&perf_reboot_notifier);
9310 ret = init_hw_breakpoint();
9311 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9313 /* do not patch jump label more than once per second */
9314 jump_label_rate_limit(&perf_sched_events, HZ);
9317 * Build time assertion that we keep the data_head at the intended
9318 * location. IOW, validation we got the __reserved[] size right.
9320 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9324 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9327 struct perf_pmu_events_attr *pmu_attr =
9328 container_of(attr, struct perf_pmu_events_attr, attr);
9330 if (pmu_attr->event_str)
9331 return sprintf(page, "%s\n", pmu_attr->event_str);
9336 static int __init perf_event_sysfs_init(void)
9341 mutex_lock(&pmus_lock);
9343 ret = bus_register(&pmu_bus);
9347 list_for_each_entry(pmu, &pmus, entry) {
9348 if (!pmu->name || pmu->type < 0)
9351 ret = pmu_dev_alloc(pmu);
9352 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9354 pmu_bus_running = 1;
9358 mutex_unlock(&pmus_lock);
9362 device_initcall(perf_event_sysfs_init);
9364 #ifdef CONFIG_CGROUP_PERF
9365 static struct cgroup_subsys_state *
9366 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9368 struct perf_cgroup *jc;
9370 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9372 return ERR_PTR(-ENOMEM);
9374 jc->info = alloc_percpu(struct perf_cgroup_info);
9377 return ERR_PTR(-ENOMEM);
9383 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9385 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9387 free_percpu(jc->info);
9391 static int __perf_cgroup_move(void *info)
9393 struct task_struct *task = info;
9395 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9400 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9402 struct task_struct *task;
9403 struct cgroup_subsys_state *css;
9405 cgroup_taskset_for_each(task, css, tset)
9406 task_function_call(task, __perf_cgroup_move, task);
9409 struct cgroup_subsys perf_event_cgrp_subsys = {
9410 .css_alloc = perf_cgroup_css_alloc,
9411 .css_free = perf_cgroup_css_free,
9412 .attach = perf_cgroup_attach,
9414 #endif /* CONFIG_CGROUP_PERF */