2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
52 #include <asm/irq_regs.h>
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())
74 * Now that we're on right CPU with IRQs disabled, we can test
75 * if we hit the right task without races.
78 tfc->ret = -ESRCH; /* No such (running) process */
83 tfc->ret = tfc->func(tfc->info);
87 * task_function_call - call a function on the cpu on which a task runs
88 * @p: the task to evaluate
89 * @func: the function to be called
90 * @info: the function call argument
92 * Calls the function @func when the task is currently running. This might
93 * be on the current CPU, which just calls the function directly
95 * returns: @func return value, or
96 * -ESRCH - when the process isn't running
97 * -EAGAIN - when the process moved away
100 task_function_call(struct task_struct *p, remote_function_f func, void *info)
102 struct remote_function_call data = {
111 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
114 } while (ret == -EAGAIN);
120 * cpu_function_call - call a function on the cpu
121 * @func: the function to be called
122 * @info: the function call argument
124 * Calls the function @func on the remote cpu.
126 * returns: @func return value or -ENXIO when the cpu is offline
128 static int cpu_function_call(int cpu, remote_function_f func, void *info)
130 struct remote_function_call data = {
134 .ret = -ENXIO, /* No such CPU */
137 smp_call_function_single(cpu, remote_function, &data, 1);
142 static inline struct perf_cpu_context *
143 __get_cpu_context(struct perf_event_context *ctx)
145 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
148 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
149 struct perf_event_context *ctx)
151 raw_spin_lock(&cpuctx->ctx.lock);
153 raw_spin_lock(&ctx->lock);
156 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
157 struct perf_event_context *ctx)
160 raw_spin_unlock(&ctx->lock);
161 raw_spin_unlock(&cpuctx->ctx.lock);
164 #define TASK_TOMBSTONE ((void *)-1L)
166 static bool is_kernel_event(struct perf_event *event)
168 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
172 * On task ctx scheduling...
174 * When !ctx->nr_events a task context will not be scheduled. This means
175 * we can disable the scheduler hooks (for performance) without leaving
176 * pending task ctx state.
178 * This however results in two special cases:
180 * - removing the last event from a task ctx; this is relatively straight
181 * forward and is done in __perf_remove_from_context.
183 * - adding the first event to a task ctx; this is tricky because we cannot
184 * rely on ctx->is_active and therefore cannot use event_function_call().
185 * See perf_install_in_context().
187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
191 struct perf_event_context *, void *);
193 struct event_function_struct {
194 struct perf_event *event;
199 static int event_function(void *info)
201 struct event_function_struct *efs = info;
202 struct perf_event *event = efs->event;
203 struct perf_event_context *ctx = event->ctx;
204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
205 struct perf_event_context *task_ctx = cpuctx->task_ctx;
208 WARN_ON_ONCE(!irqs_disabled());
210 perf_ctx_lock(cpuctx, task_ctx);
212 * Since we do the IPI call without holding ctx->lock things can have
213 * changed, double check we hit the task we set out to hit.
216 if (ctx->task != current) {
222 * We only use event_function_call() on established contexts,
223 * and event_function() is only ever called when active (or
224 * rather, we'll have bailed in task_function_call() or the
225 * above ctx->task != current test), therefore we must have
226 * ctx->is_active here.
228 WARN_ON_ONCE(!ctx->is_active);
230 * And since we have ctx->is_active, cpuctx->task_ctx must
233 WARN_ON_ONCE(task_ctx != ctx);
235 WARN_ON_ONCE(&cpuctx->ctx != ctx);
238 efs->func(event, cpuctx, ctx, efs->data);
240 perf_ctx_unlock(cpuctx, task_ctx);
245 static void event_function_call(struct perf_event *event, event_f func, void *data)
247 struct perf_event_context *ctx = event->ctx;
248 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
249 struct event_function_struct efs = {
255 if (!event->parent) {
257 * If this is a !child event, we must hold ctx::mutex to
258 * stabilize the the event->ctx relation. See
259 * perf_event_ctx_lock().
261 lockdep_assert_held(&ctx->mutex);
265 cpu_function_call(event->cpu, event_function, &efs);
269 if (task == TASK_TOMBSTONE)
273 if (!task_function_call(task, event_function, &efs))
276 raw_spin_lock_irq(&ctx->lock);
278 * Reload the task pointer, it might have been changed by
279 * a concurrent perf_event_context_sched_out().
282 if (task == TASK_TOMBSTONE) {
283 raw_spin_unlock_irq(&ctx->lock);
286 if (ctx->is_active) {
287 raw_spin_unlock_irq(&ctx->lock);
290 func(event, NULL, ctx, data);
291 raw_spin_unlock_irq(&ctx->lock);
295 * Similar to event_function_call() + event_function(), but hard assumes IRQs
296 * are already disabled and we're on the right CPU.
298 static void event_function_local(struct perf_event *event, event_f func, void *data)
300 struct perf_event_context *ctx = event->ctx;
301 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
302 struct task_struct *task = READ_ONCE(ctx->task);
303 struct perf_event_context *task_ctx = NULL;
305 WARN_ON_ONCE(!irqs_disabled());
308 if (task == TASK_TOMBSTONE)
314 perf_ctx_lock(cpuctx, task_ctx);
317 if (task == TASK_TOMBSTONE)
322 * We must be either inactive or active and the right task,
323 * otherwise we're screwed, since we cannot IPI to somewhere
326 if (ctx->is_active) {
327 if (WARN_ON_ONCE(task != current))
330 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
334 WARN_ON_ONCE(&cpuctx->ctx != ctx);
337 func(event, cpuctx, ctx, data);
339 perf_ctx_unlock(cpuctx, task_ctx);
342 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
343 PERF_FLAG_FD_OUTPUT |\
344 PERF_FLAG_PID_CGROUP |\
345 PERF_FLAG_FD_CLOEXEC)
348 * branch priv levels that need permission checks
350 #define PERF_SAMPLE_BRANCH_PERM_PLM \
351 (PERF_SAMPLE_BRANCH_KERNEL |\
352 PERF_SAMPLE_BRANCH_HV)
355 EVENT_FLEXIBLE = 0x1,
358 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
362 * perf_sched_events : >0 events exist
363 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
366 static void perf_sched_delayed(struct work_struct *work);
367 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
368 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
369 static DEFINE_MUTEX(perf_sched_mutex);
370 static atomic_t perf_sched_count;
372 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
373 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
374 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
376 static atomic_t nr_mmap_events __read_mostly;
377 static atomic_t nr_comm_events __read_mostly;
378 static atomic_t nr_task_events __read_mostly;
379 static atomic_t nr_freq_events __read_mostly;
380 static atomic_t nr_switch_events __read_mostly;
382 static LIST_HEAD(pmus);
383 static DEFINE_MUTEX(pmus_lock);
384 static struct srcu_struct pmus_srcu;
387 * perf event paranoia level:
388 * -1 - not paranoid at all
389 * 0 - disallow raw tracepoint access for unpriv
390 * 1 - disallow cpu events for unpriv
391 * 2 - disallow kernel profiling for unpriv
393 int sysctl_perf_event_paranoid __read_mostly = 2;
395 /* Minimum for 512 kiB + 1 user control page */
396 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
399 * max perf event sample rate
401 #define DEFAULT_MAX_SAMPLE_RATE 100000
402 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
403 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
405 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
407 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
408 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
410 static int perf_sample_allowed_ns __read_mostly =
411 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
413 static void update_perf_cpu_limits(void)
415 u64 tmp = perf_sample_period_ns;
417 tmp *= sysctl_perf_cpu_time_max_percent;
418 tmp = div_u64(tmp, 100);
422 WRITE_ONCE(perf_sample_allowed_ns, tmp);
425 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
427 int perf_proc_update_handler(struct ctl_table *table, int write,
428 void __user *buffer, size_t *lenp,
431 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
437 * If throttling is disabled don't allow the write:
439 if (sysctl_perf_cpu_time_max_percent == 100 ||
440 sysctl_perf_cpu_time_max_percent == 0)
443 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
444 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
445 update_perf_cpu_limits();
450 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
452 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
453 void __user *buffer, size_t *lenp,
456 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
461 if (sysctl_perf_cpu_time_max_percent == 100 ||
462 sysctl_perf_cpu_time_max_percent == 0) {
464 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
465 WRITE_ONCE(perf_sample_allowed_ns, 0);
467 update_perf_cpu_limits();
474 * perf samples are done in some very critical code paths (NMIs).
475 * If they take too much CPU time, the system can lock up and not
476 * get any real work done. This will drop the sample rate when
477 * we detect that events are taking too long.
479 #define NR_ACCUMULATED_SAMPLES 128
480 static DEFINE_PER_CPU(u64, running_sample_length);
482 static u64 __report_avg;
483 static u64 __report_allowed;
485 static void perf_duration_warn(struct irq_work *w)
487 printk_ratelimited(KERN_INFO
488 "perf: interrupt took too long (%lld > %lld), lowering "
489 "kernel.perf_event_max_sample_rate to %d\n",
490 __report_avg, __report_allowed,
491 sysctl_perf_event_sample_rate);
494 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
496 void perf_sample_event_took(u64 sample_len_ns)
498 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
506 /* Decay the counter by 1 average sample. */
507 running_len = __this_cpu_read(running_sample_length);
508 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
509 running_len += sample_len_ns;
510 __this_cpu_write(running_sample_length, running_len);
513 * Note: this will be biased artifically low until we have
514 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
515 * from having to maintain a count.
517 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
518 if (avg_len <= max_len)
521 __report_avg = avg_len;
522 __report_allowed = max_len;
525 * Compute a throttle threshold 25% below the current duration.
527 avg_len += avg_len / 4;
528 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
534 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
535 WRITE_ONCE(max_samples_per_tick, max);
537 sysctl_perf_event_sample_rate = max * HZ;
538 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
540 if (!irq_work_queue(&perf_duration_work)) {
541 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
542 "kernel.perf_event_max_sample_rate to %d\n",
543 __report_avg, __report_allowed,
544 sysctl_perf_event_sample_rate);
548 static atomic64_t perf_event_id;
550 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
551 enum event_type_t event_type);
553 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
554 enum event_type_t event_type,
555 struct task_struct *task);
557 static void update_context_time(struct perf_event_context *ctx);
558 static u64 perf_event_time(struct perf_event *event);
560 void __weak perf_event_print_debug(void) { }
562 extern __weak const char *perf_pmu_name(void)
567 static inline u64 perf_clock(void)
569 return local_clock();
572 static inline u64 perf_event_clock(struct perf_event *event)
574 return event->clock();
577 #ifdef CONFIG_CGROUP_PERF
580 perf_cgroup_match(struct perf_event *event)
582 struct perf_event_context *ctx = event->ctx;
583 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
585 /* @event doesn't care about cgroup */
589 /* wants specific cgroup scope but @cpuctx isn't associated with any */
594 * Cgroup scoping is recursive. An event enabled for a cgroup is
595 * also enabled for all its descendant cgroups. If @cpuctx's
596 * cgroup is a descendant of @event's (the test covers identity
597 * case), it's a match.
599 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
600 event->cgrp->css.cgroup);
603 static inline void perf_detach_cgroup(struct perf_event *event)
605 css_put(&event->cgrp->css);
609 static inline int is_cgroup_event(struct perf_event *event)
611 return event->cgrp != NULL;
614 static inline u64 perf_cgroup_event_time(struct perf_event *event)
616 struct perf_cgroup_info *t;
618 t = per_cpu_ptr(event->cgrp->info, event->cpu);
622 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
624 struct perf_cgroup_info *info;
629 info = this_cpu_ptr(cgrp->info);
631 info->time += now - info->timestamp;
632 info->timestamp = now;
635 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
637 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
639 __update_cgrp_time(cgrp_out);
642 static inline void update_cgrp_time_from_event(struct perf_event *event)
644 struct perf_cgroup *cgrp;
647 * ensure we access cgroup data only when needed and
648 * when we know the cgroup is pinned (css_get)
650 if (!is_cgroup_event(event))
653 cgrp = perf_cgroup_from_task(current, event->ctx);
655 * Do not update time when cgroup is not active
657 if (cgrp == event->cgrp)
658 __update_cgrp_time(event->cgrp);
662 perf_cgroup_set_timestamp(struct task_struct *task,
663 struct perf_event_context *ctx)
665 struct perf_cgroup *cgrp;
666 struct perf_cgroup_info *info;
669 * ctx->lock held by caller
670 * ensure we do not access cgroup data
671 * unless we have the cgroup pinned (css_get)
673 if (!task || !ctx->nr_cgroups)
676 cgrp = perf_cgroup_from_task(task, ctx);
677 info = this_cpu_ptr(cgrp->info);
678 info->timestamp = ctx->timestamp;
681 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
682 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
685 * reschedule events based on the cgroup constraint of task.
687 * mode SWOUT : schedule out everything
688 * mode SWIN : schedule in based on cgroup for next
690 static void perf_cgroup_switch(struct task_struct *task, int mode)
692 struct perf_cpu_context *cpuctx;
697 * disable interrupts to avoid geting nr_cgroup
698 * changes via __perf_event_disable(). Also
701 local_irq_save(flags);
704 * we reschedule only in the presence of cgroup
705 * constrained events.
708 list_for_each_entry_rcu(pmu, &pmus, entry) {
709 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
710 if (cpuctx->unique_pmu != pmu)
711 continue; /* ensure we process each cpuctx once */
714 * perf_cgroup_events says at least one
715 * context on this CPU has cgroup events.
717 * ctx->nr_cgroups reports the number of cgroup
718 * events for a context.
720 if (cpuctx->ctx.nr_cgroups > 0) {
721 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
722 perf_pmu_disable(cpuctx->ctx.pmu);
724 if (mode & PERF_CGROUP_SWOUT) {
725 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
727 * must not be done before ctxswout due
728 * to event_filter_match() in event_sched_out()
733 if (mode & PERF_CGROUP_SWIN) {
734 WARN_ON_ONCE(cpuctx->cgrp);
736 * set cgrp before ctxsw in to allow
737 * event_filter_match() to not have to pass
739 * we pass the cpuctx->ctx to perf_cgroup_from_task()
740 * because cgorup events are only per-cpu
742 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
743 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
745 perf_pmu_enable(cpuctx->ctx.pmu);
746 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
750 local_irq_restore(flags);
753 static inline void perf_cgroup_sched_out(struct task_struct *task,
754 struct task_struct *next)
756 struct perf_cgroup *cgrp1;
757 struct perf_cgroup *cgrp2 = NULL;
761 * we come here when we know perf_cgroup_events > 0
762 * we do not need to pass the ctx here because we know
763 * we are holding the rcu lock
765 cgrp1 = perf_cgroup_from_task(task, NULL);
766 cgrp2 = perf_cgroup_from_task(next, NULL);
769 * only schedule out current cgroup events if we know
770 * that we are switching to a different cgroup. Otherwise,
771 * do no touch the cgroup events.
774 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
779 static inline void perf_cgroup_sched_in(struct task_struct *prev,
780 struct task_struct *task)
782 struct perf_cgroup *cgrp1;
783 struct perf_cgroup *cgrp2 = NULL;
787 * we come here when we know perf_cgroup_events > 0
788 * we do not need to pass the ctx here because we know
789 * we are holding the rcu lock
791 cgrp1 = perf_cgroup_from_task(task, NULL);
792 cgrp2 = perf_cgroup_from_task(prev, NULL);
795 * only need to schedule in cgroup events if we are changing
796 * cgroup during ctxsw. Cgroup events were not scheduled
797 * out of ctxsw out if that was not the case.
800 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
805 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
806 struct perf_event_attr *attr,
807 struct perf_event *group_leader)
809 struct perf_cgroup *cgrp;
810 struct cgroup_subsys_state *css;
811 struct fd f = fdget(fd);
817 css = css_tryget_online_from_dir(f.file->f_path.dentry,
818 &perf_event_cgrp_subsys);
824 cgrp = container_of(css, struct perf_cgroup, css);
828 * all events in a group must monitor
829 * the same cgroup because a task belongs
830 * to only one perf cgroup at a time
832 if (group_leader && group_leader->cgrp != cgrp) {
833 perf_detach_cgroup(event);
842 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
844 struct perf_cgroup_info *t;
845 t = per_cpu_ptr(event->cgrp->info, event->cpu);
846 event->shadow_ctx_time = now - t->timestamp;
850 perf_cgroup_defer_enabled(struct perf_event *event)
853 * when the current task's perf cgroup does not match
854 * the event's, we need to remember to call the
855 * perf_mark_enable() function the first time a task with
856 * a matching perf cgroup is scheduled in.
858 if (is_cgroup_event(event) && !perf_cgroup_match(event))
859 event->cgrp_defer_enabled = 1;
863 perf_cgroup_mark_enabled(struct perf_event *event,
864 struct perf_event_context *ctx)
866 struct perf_event *sub;
867 u64 tstamp = perf_event_time(event);
869 if (!event->cgrp_defer_enabled)
872 event->cgrp_defer_enabled = 0;
874 event->tstamp_enabled = tstamp - event->total_time_enabled;
875 list_for_each_entry(sub, &event->sibling_list, group_entry) {
876 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
877 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
878 sub->cgrp_defer_enabled = 0;
884 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
885 * cleared when last cgroup event is removed.
888 list_update_cgroup_event(struct perf_event *event,
889 struct perf_event_context *ctx, bool add)
891 struct perf_cpu_context *cpuctx;
893 if (!is_cgroup_event(event))
896 if (add && ctx->nr_cgroups++)
898 else if (!add && --ctx->nr_cgroups)
901 * Because cgroup events are always per-cpu events,
902 * this will always be called from the right CPU.
904 cpuctx = __get_cpu_context(ctx);
905 cpuctx->cgrp = add ? event->cgrp : NULL;
908 #else /* !CONFIG_CGROUP_PERF */
911 perf_cgroup_match(struct perf_event *event)
916 static inline void perf_detach_cgroup(struct perf_event *event)
919 static inline int is_cgroup_event(struct perf_event *event)
924 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
929 static inline void update_cgrp_time_from_event(struct perf_event *event)
933 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
937 static inline void perf_cgroup_sched_out(struct task_struct *task,
938 struct task_struct *next)
942 static inline void perf_cgroup_sched_in(struct task_struct *prev,
943 struct task_struct *task)
947 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
948 struct perf_event_attr *attr,
949 struct perf_event *group_leader)
955 perf_cgroup_set_timestamp(struct task_struct *task,
956 struct perf_event_context *ctx)
961 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
966 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
970 static inline u64 perf_cgroup_event_time(struct perf_event *event)
976 perf_cgroup_defer_enabled(struct perf_event *event)
981 perf_cgroup_mark_enabled(struct perf_event *event,
982 struct perf_event_context *ctx)
987 list_update_cgroup_event(struct perf_event *event,
988 struct perf_event_context *ctx, bool add)
995 * set default to be dependent on timer tick just
998 #define PERF_CPU_HRTIMER (1000 / HZ)
1000 * function must be called with interrupts disbled
1002 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1004 struct perf_cpu_context *cpuctx;
1007 WARN_ON(!irqs_disabled());
1009 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1010 rotations = perf_rotate_context(cpuctx);
1012 raw_spin_lock(&cpuctx->hrtimer_lock);
1014 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1016 cpuctx->hrtimer_active = 0;
1017 raw_spin_unlock(&cpuctx->hrtimer_lock);
1019 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1022 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1024 struct hrtimer *timer = &cpuctx->hrtimer;
1025 struct pmu *pmu = cpuctx->ctx.pmu;
1028 /* no multiplexing needed for SW PMU */
1029 if (pmu->task_ctx_nr == perf_sw_context)
1033 * check default is sane, if not set then force to
1034 * default interval (1/tick)
1036 interval = pmu->hrtimer_interval_ms;
1038 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1040 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1042 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1043 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1044 timer->function = perf_mux_hrtimer_handler;
1047 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1049 struct hrtimer *timer = &cpuctx->hrtimer;
1050 struct pmu *pmu = cpuctx->ctx.pmu;
1051 unsigned long flags;
1053 /* not for SW PMU */
1054 if (pmu->task_ctx_nr == perf_sw_context)
1057 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1058 if (!cpuctx->hrtimer_active) {
1059 cpuctx->hrtimer_active = 1;
1060 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1061 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1063 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1068 void perf_pmu_disable(struct pmu *pmu)
1070 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1072 pmu->pmu_disable(pmu);
1075 void perf_pmu_enable(struct pmu *pmu)
1077 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1079 pmu->pmu_enable(pmu);
1082 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1085 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1086 * perf_event_task_tick() are fully serialized because they're strictly cpu
1087 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1088 * disabled, while perf_event_task_tick is called from IRQ context.
1090 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1092 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1094 WARN_ON(!irqs_disabled());
1096 WARN_ON(!list_empty(&ctx->active_ctx_list));
1098 list_add(&ctx->active_ctx_list, head);
1101 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1103 WARN_ON(!irqs_disabled());
1105 WARN_ON(list_empty(&ctx->active_ctx_list));
1107 list_del_init(&ctx->active_ctx_list);
1110 static void get_ctx(struct perf_event_context *ctx)
1112 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1115 static void free_ctx(struct rcu_head *head)
1117 struct perf_event_context *ctx;
1119 ctx = container_of(head, struct perf_event_context, rcu_head);
1120 kfree(ctx->task_ctx_data);
1124 static void put_ctx(struct perf_event_context *ctx)
1126 if (atomic_dec_and_test(&ctx->refcount)) {
1127 if (ctx->parent_ctx)
1128 put_ctx(ctx->parent_ctx);
1129 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1130 put_task_struct(ctx->task);
1131 call_rcu(&ctx->rcu_head, free_ctx);
1136 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1137 * perf_pmu_migrate_context() we need some magic.
1139 * Those places that change perf_event::ctx will hold both
1140 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1142 * Lock ordering is by mutex address. There are two other sites where
1143 * perf_event_context::mutex nests and those are:
1145 * - perf_event_exit_task_context() [ child , 0 ]
1146 * perf_event_exit_event()
1147 * put_event() [ parent, 1 ]
1149 * - perf_event_init_context() [ parent, 0 ]
1150 * inherit_task_group()
1153 * perf_event_alloc()
1155 * perf_try_init_event() [ child , 1 ]
1157 * While it appears there is an obvious deadlock here -- the parent and child
1158 * nesting levels are inverted between the two. This is in fact safe because
1159 * life-time rules separate them. That is an exiting task cannot fork, and a
1160 * spawning task cannot (yet) exit.
1162 * But remember that that these are parent<->child context relations, and
1163 * migration does not affect children, therefore these two orderings should not
1166 * The change in perf_event::ctx does not affect children (as claimed above)
1167 * because the sys_perf_event_open() case will install a new event and break
1168 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1169 * concerned with cpuctx and that doesn't have children.
1171 * The places that change perf_event::ctx will issue:
1173 * perf_remove_from_context();
1174 * synchronize_rcu();
1175 * perf_install_in_context();
1177 * to affect the change. The remove_from_context() + synchronize_rcu() should
1178 * quiesce the event, after which we can install it in the new location. This
1179 * means that only external vectors (perf_fops, prctl) can perturb the event
1180 * while in transit. Therefore all such accessors should also acquire
1181 * perf_event_context::mutex to serialize against this.
1183 * However; because event->ctx can change while we're waiting to acquire
1184 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1189 * task_struct::perf_event_mutex
1190 * perf_event_context::mutex
1191 * perf_event::child_mutex;
1192 * perf_event_context::lock
1193 * perf_event::mmap_mutex
1196 static struct perf_event_context *
1197 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1199 struct perf_event_context *ctx;
1203 ctx = ACCESS_ONCE(event->ctx);
1204 if (!atomic_inc_not_zero(&ctx->refcount)) {
1210 mutex_lock_nested(&ctx->mutex, nesting);
1211 if (event->ctx != ctx) {
1212 mutex_unlock(&ctx->mutex);
1220 static inline struct perf_event_context *
1221 perf_event_ctx_lock(struct perf_event *event)
1223 return perf_event_ctx_lock_nested(event, 0);
1226 static void perf_event_ctx_unlock(struct perf_event *event,
1227 struct perf_event_context *ctx)
1229 mutex_unlock(&ctx->mutex);
1234 * This must be done under the ctx->lock, such as to serialize against
1235 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1236 * calling scheduler related locks and ctx->lock nests inside those.
1238 static __must_check struct perf_event_context *
1239 unclone_ctx(struct perf_event_context *ctx)
1241 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1243 lockdep_assert_held(&ctx->lock);
1246 ctx->parent_ctx = NULL;
1252 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1255 * only top level events have the pid namespace they were created in
1258 event = event->parent;
1260 return task_tgid_nr_ns(p, event->ns);
1263 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1266 * only top level events have the pid namespace they were created in
1269 event = event->parent;
1271 return task_pid_nr_ns(p, event->ns);
1275 * If we inherit events we want to return the parent event id
1278 static u64 primary_event_id(struct perf_event *event)
1283 id = event->parent->id;
1289 * Get the perf_event_context for a task and lock it.
1291 * This has to cope with with the fact that until it is locked,
1292 * the context could get moved to another task.
1294 static struct perf_event_context *
1295 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1297 struct perf_event_context *ctx;
1301 * One of the few rules of preemptible RCU is that one cannot do
1302 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1303 * part of the read side critical section was irqs-enabled -- see
1304 * rcu_read_unlock_special().
1306 * Since ctx->lock nests under rq->lock we must ensure the entire read
1307 * side critical section has interrupts disabled.
1309 local_irq_save(*flags);
1311 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1314 * If this context is a clone of another, it might
1315 * get swapped for another underneath us by
1316 * perf_event_task_sched_out, though the
1317 * rcu_read_lock() protects us from any context
1318 * getting freed. Lock the context and check if it
1319 * got swapped before we could get the lock, and retry
1320 * if so. If we locked the right context, then it
1321 * can't get swapped on us any more.
1323 raw_spin_lock(&ctx->lock);
1324 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1325 raw_spin_unlock(&ctx->lock);
1327 local_irq_restore(*flags);
1331 if (ctx->task == TASK_TOMBSTONE ||
1332 !atomic_inc_not_zero(&ctx->refcount)) {
1333 raw_spin_unlock(&ctx->lock);
1336 WARN_ON_ONCE(ctx->task != task);
1341 local_irq_restore(*flags);
1346 * Get the context for a task and increment its pin_count so it
1347 * can't get swapped to another task. This also increments its
1348 * reference count so that the context can't get freed.
1350 static struct perf_event_context *
1351 perf_pin_task_context(struct task_struct *task, int ctxn)
1353 struct perf_event_context *ctx;
1354 unsigned long flags;
1356 ctx = perf_lock_task_context(task, ctxn, &flags);
1359 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1364 static void perf_unpin_context(struct perf_event_context *ctx)
1366 unsigned long flags;
1368 raw_spin_lock_irqsave(&ctx->lock, flags);
1370 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1374 * Update the record of the current time in a context.
1376 static void update_context_time(struct perf_event_context *ctx)
1378 u64 now = perf_clock();
1380 ctx->time += now - ctx->timestamp;
1381 ctx->timestamp = now;
1384 static u64 perf_event_time(struct perf_event *event)
1386 struct perf_event_context *ctx = event->ctx;
1388 if (is_cgroup_event(event))
1389 return perf_cgroup_event_time(event);
1391 return ctx ? ctx->time : 0;
1395 * Update the total_time_enabled and total_time_running fields for a event.
1397 static void update_event_times(struct perf_event *event)
1399 struct perf_event_context *ctx = event->ctx;
1402 lockdep_assert_held(&ctx->lock);
1404 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1405 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1409 * in cgroup mode, time_enabled represents
1410 * the time the event was enabled AND active
1411 * tasks were in the monitored cgroup. This is
1412 * independent of the activity of the context as
1413 * there may be a mix of cgroup and non-cgroup events.
1415 * That is why we treat cgroup events differently
1418 if (is_cgroup_event(event))
1419 run_end = perf_cgroup_event_time(event);
1420 else if (ctx->is_active)
1421 run_end = ctx->time;
1423 run_end = event->tstamp_stopped;
1425 event->total_time_enabled = run_end - event->tstamp_enabled;
1427 if (event->state == PERF_EVENT_STATE_INACTIVE)
1428 run_end = event->tstamp_stopped;
1430 run_end = perf_event_time(event);
1432 event->total_time_running = run_end - event->tstamp_running;
1437 * Update total_time_enabled and total_time_running for all events in a group.
1439 static void update_group_times(struct perf_event *leader)
1441 struct perf_event *event;
1443 update_event_times(leader);
1444 list_for_each_entry(event, &leader->sibling_list, group_entry)
1445 update_event_times(event);
1448 static struct list_head *
1449 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1451 if (event->attr.pinned)
1452 return &ctx->pinned_groups;
1454 return &ctx->flexible_groups;
1458 * Add a event from the lists for its context.
1459 * Must be called with ctx->mutex and ctx->lock held.
1462 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1465 lockdep_assert_held(&ctx->lock);
1467 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1468 event->attach_state |= PERF_ATTACH_CONTEXT;
1471 * If we're a stand alone event or group leader, we go to the context
1472 * list, group events are kept attached to the group so that
1473 * perf_group_detach can, at all times, locate all siblings.
1475 if (event->group_leader == event) {
1476 struct list_head *list;
1478 event->group_caps = event->event_caps;
1480 list = ctx_group_list(event, ctx);
1481 list_add_tail(&event->group_entry, list);
1484 list_update_cgroup_event(event, ctx, true);
1486 list_add_rcu(&event->event_entry, &ctx->event_list);
1488 if (event->attr.inherit_stat)
1495 * Initialize event state based on the perf_event_attr::disabled.
1497 static inline void perf_event__state_init(struct perf_event *event)
1499 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1500 PERF_EVENT_STATE_INACTIVE;
1503 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1505 int entry = sizeof(u64); /* value */
1509 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1510 size += sizeof(u64);
1512 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1513 size += sizeof(u64);
1515 if (event->attr.read_format & PERF_FORMAT_ID)
1516 entry += sizeof(u64);
1518 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1520 size += sizeof(u64);
1524 event->read_size = size;
1527 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1529 struct perf_sample_data *data;
1532 if (sample_type & PERF_SAMPLE_IP)
1533 size += sizeof(data->ip);
1535 if (sample_type & PERF_SAMPLE_ADDR)
1536 size += sizeof(data->addr);
1538 if (sample_type & PERF_SAMPLE_PERIOD)
1539 size += sizeof(data->period);
1541 if (sample_type & PERF_SAMPLE_WEIGHT)
1542 size += sizeof(data->weight);
1544 if (sample_type & PERF_SAMPLE_READ)
1545 size += event->read_size;
1547 if (sample_type & PERF_SAMPLE_DATA_SRC)
1548 size += sizeof(data->data_src.val);
1550 if (sample_type & PERF_SAMPLE_TRANSACTION)
1551 size += sizeof(data->txn);
1553 event->header_size = size;
1557 * Called at perf_event creation and when events are attached/detached from a
1560 static void perf_event__header_size(struct perf_event *event)
1562 __perf_event_read_size(event,
1563 event->group_leader->nr_siblings);
1564 __perf_event_header_size(event, event->attr.sample_type);
1567 static void perf_event__id_header_size(struct perf_event *event)
1569 struct perf_sample_data *data;
1570 u64 sample_type = event->attr.sample_type;
1573 if (sample_type & PERF_SAMPLE_TID)
1574 size += sizeof(data->tid_entry);
1576 if (sample_type & PERF_SAMPLE_TIME)
1577 size += sizeof(data->time);
1579 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1580 size += sizeof(data->id);
1582 if (sample_type & PERF_SAMPLE_ID)
1583 size += sizeof(data->id);
1585 if (sample_type & PERF_SAMPLE_STREAM_ID)
1586 size += sizeof(data->stream_id);
1588 if (sample_type & PERF_SAMPLE_CPU)
1589 size += sizeof(data->cpu_entry);
1591 event->id_header_size = size;
1594 static bool perf_event_validate_size(struct perf_event *event)
1597 * The values computed here will be over-written when we actually
1600 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1601 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1602 perf_event__id_header_size(event);
1605 * Sum the lot; should not exceed the 64k limit we have on records.
1606 * Conservative limit to allow for callchains and other variable fields.
1608 if (event->read_size + event->header_size +
1609 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1615 static void perf_group_attach(struct perf_event *event)
1617 struct perf_event *group_leader = event->group_leader, *pos;
1620 * We can have double attach due to group movement in perf_event_open.
1622 if (event->attach_state & PERF_ATTACH_GROUP)
1625 event->attach_state |= PERF_ATTACH_GROUP;
1627 if (group_leader == event)
1630 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1632 group_leader->group_caps &= event->event_caps;
1634 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1635 group_leader->nr_siblings++;
1637 perf_event__header_size(group_leader);
1639 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1640 perf_event__header_size(pos);
1644 * Remove a event from the lists for its context.
1645 * Must be called with ctx->mutex and ctx->lock held.
1648 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1650 WARN_ON_ONCE(event->ctx != ctx);
1651 lockdep_assert_held(&ctx->lock);
1654 * We can have double detach due to exit/hot-unplug + close.
1656 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1659 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1661 list_update_cgroup_event(event, ctx, false);
1664 if (event->attr.inherit_stat)
1667 list_del_rcu(&event->event_entry);
1669 if (event->group_leader == event)
1670 list_del_init(&event->group_entry);
1672 update_group_times(event);
1675 * If event was in error state, then keep it
1676 * that way, otherwise bogus counts will be
1677 * returned on read(). The only way to get out
1678 * of error state is by explicit re-enabling
1681 if (event->state > PERF_EVENT_STATE_OFF)
1682 event->state = PERF_EVENT_STATE_OFF;
1687 static void perf_group_detach(struct perf_event *event)
1689 struct perf_event *sibling, *tmp;
1690 struct list_head *list = NULL;
1693 * We can have double detach due to exit/hot-unplug + close.
1695 if (!(event->attach_state & PERF_ATTACH_GROUP))
1698 event->attach_state &= ~PERF_ATTACH_GROUP;
1701 * If this is a sibling, remove it from its group.
1703 if (event->group_leader != event) {
1704 list_del_init(&event->group_entry);
1705 event->group_leader->nr_siblings--;
1709 if (!list_empty(&event->group_entry))
1710 list = &event->group_entry;
1713 * If this was a group event with sibling events then
1714 * upgrade the siblings to singleton events by adding them
1715 * to whatever list we are on.
1717 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1719 list_move_tail(&sibling->group_entry, list);
1720 sibling->group_leader = sibling;
1722 /* Inherit group flags from the previous leader */
1723 sibling->group_caps = event->group_caps;
1725 WARN_ON_ONCE(sibling->ctx != event->ctx);
1729 perf_event__header_size(event->group_leader);
1731 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1732 perf_event__header_size(tmp);
1735 static bool is_orphaned_event(struct perf_event *event)
1737 return event->state == PERF_EVENT_STATE_DEAD;
1740 static inline int __pmu_filter_match(struct perf_event *event)
1742 struct pmu *pmu = event->pmu;
1743 return pmu->filter_match ? pmu->filter_match(event) : 1;
1747 * Check whether we should attempt to schedule an event group based on
1748 * PMU-specific filtering. An event group can consist of HW and SW events,
1749 * potentially with a SW leader, so we must check all the filters, to
1750 * determine whether a group is schedulable:
1752 static inline int pmu_filter_match(struct perf_event *event)
1754 struct perf_event *child;
1756 if (!__pmu_filter_match(event))
1759 list_for_each_entry(child, &event->sibling_list, group_entry) {
1760 if (!__pmu_filter_match(child))
1768 event_filter_match(struct perf_event *event)
1770 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1771 perf_cgroup_match(event) && pmu_filter_match(event);
1775 event_sched_out(struct perf_event *event,
1776 struct perf_cpu_context *cpuctx,
1777 struct perf_event_context *ctx)
1779 u64 tstamp = perf_event_time(event);
1782 WARN_ON_ONCE(event->ctx != ctx);
1783 lockdep_assert_held(&ctx->lock);
1786 * An event which could not be activated because of
1787 * filter mismatch still needs to have its timings
1788 * maintained, otherwise bogus information is return
1789 * via read() for time_enabled, time_running:
1791 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1792 !event_filter_match(event)) {
1793 delta = tstamp - event->tstamp_stopped;
1794 event->tstamp_running += delta;
1795 event->tstamp_stopped = tstamp;
1798 if (event->state != PERF_EVENT_STATE_ACTIVE)
1801 perf_pmu_disable(event->pmu);
1803 event->tstamp_stopped = tstamp;
1804 event->pmu->del(event, 0);
1806 event->state = PERF_EVENT_STATE_INACTIVE;
1807 if (event->pending_disable) {
1808 event->pending_disable = 0;
1809 event->state = PERF_EVENT_STATE_OFF;
1812 if (!is_software_event(event))
1813 cpuctx->active_oncpu--;
1814 if (!--ctx->nr_active)
1815 perf_event_ctx_deactivate(ctx);
1816 if (event->attr.freq && event->attr.sample_freq)
1818 if (event->attr.exclusive || !cpuctx->active_oncpu)
1819 cpuctx->exclusive = 0;
1821 perf_pmu_enable(event->pmu);
1825 group_sched_out(struct perf_event *group_event,
1826 struct perf_cpu_context *cpuctx,
1827 struct perf_event_context *ctx)
1829 struct perf_event *event;
1830 int state = group_event->state;
1832 perf_pmu_disable(ctx->pmu);
1834 event_sched_out(group_event, cpuctx, ctx);
1837 * Schedule out siblings (if any):
1839 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1840 event_sched_out(event, cpuctx, ctx);
1842 perf_pmu_enable(ctx->pmu);
1844 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1845 cpuctx->exclusive = 0;
1848 #define DETACH_GROUP 0x01UL
1851 * Cross CPU call to remove a performance event
1853 * We disable the event on the hardware level first. After that we
1854 * remove it from the context list.
1857 __perf_remove_from_context(struct perf_event *event,
1858 struct perf_cpu_context *cpuctx,
1859 struct perf_event_context *ctx,
1862 unsigned long flags = (unsigned long)info;
1864 event_sched_out(event, cpuctx, ctx);
1865 if (flags & DETACH_GROUP)
1866 perf_group_detach(event);
1867 list_del_event(event, ctx);
1869 if (!ctx->nr_events && ctx->is_active) {
1872 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1873 cpuctx->task_ctx = NULL;
1879 * Remove the event from a task's (or a CPU's) list of events.
1881 * If event->ctx is a cloned context, callers must make sure that
1882 * every task struct that event->ctx->task could possibly point to
1883 * remains valid. This is OK when called from perf_release since
1884 * that only calls us on the top-level context, which can't be a clone.
1885 * When called from perf_event_exit_task, it's OK because the
1886 * context has been detached from its task.
1888 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1890 lockdep_assert_held(&event->ctx->mutex);
1892 event_function_call(event, __perf_remove_from_context, (void *)flags);
1896 * Cross CPU call to disable a performance event
1898 static void __perf_event_disable(struct perf_event *event,
1899 struct perf_cpu_context *cpuctx,
1900 struct perf_event_context *ctx,
1903 if (event->state < PERF_EVENT_STATE_INACTIVE)
1906 update_context_time(ctx);
1907 update_cgrp_time_from_event(event);
1908 update_group_times(event);
1909 if (event == event->group_leader)
1910 group_sched_out(event, cpuctx, ctx);
1912 event_sched_out(event, cpuctx, ctx);
1913 event->state = PERF_EVENT_STATE_OFF;
1919 * If event->ctx is a cloned context, callers must make sure that
1920 * every task struct that event->ctx->task could possibly point to
1921 * remains valid. This condition is satisifed when called through
1922 * perf_event_for_each_child or perf_event_for_each because they
1923 * hold the top-level event's child_mutex, so any descendant that
1924 * goes to exit will block in perf_event_exit_event().
1926 * When called from perf_pending_event it's OK because event->ctx
1927 * is the current context on this CPU and preemption is disabled,
1928 * hence we can't get into perf_event_task_sched_out for this context.
1930 static void _perf_event_disable(struct perf_event *event)
1932 struct perf_event_context *ctx = event->ctx;
1934 raw_spin_lock_irq(&ctx->lock);
1935 if (event->state <= PERF_EVENT_STATE_OFF) {
1936 raw_spin_unlock_irq(&ctx->lock);
1939 raw_spin_unlock_irq(&ctx->lock);
1941 event_function_call(event, __perf_event_disable, NULL);
1944 void perf_event_disable_local(struct perf_event *event)
1946 event_function_local(event, __perf_event_disable, NULL);
1950 * Strictly speaking kernel users cannot create groups and therefore this
1951 * interface does not need the perf_event_ctx_lock() magic.
1953 void perf_event_disable(struct perf_event *event)
1955 struct perf_event_context *ctx;
1957 ctx = perf_event_ctx_lock(event);
1958 _perf_event_disable(event);
1959 perf_event_ctx_unlock(event, ctx);
1961 EXPORT_SYMBOL_GPL(perf_event_disable);
1963 static void perf_set_shadow_time(struct perf_event *event,
1964 struct perf_event_context *ctx,
1968 * use the correct time source for the time snapshot
1970 * We could get by without this by leveraging the
1971 * fact that to get to this function, the caller
1972 * has most likely already called update_context_time()
1973 * and update_cgrp_time_xx() and thus both timestamp
1974 * are identical (or very close). Given that tstamp is,
1975 * already adjusted for cgroup, we could say that:
1976 * tstamp - ctx->timestamp
1978 * tstamp - cgrp->timestamp.
1980 * Then, in perf_output_read(), the calculation would
1981 * work with no changes because:
1982 * - event is guaranteed scheduled in
1983 * - no scheduled out in between
1984 * - thus the timestamp would be the same
1986 * But this is a bit hairy.
1988 * So instead, we have an explicit cgroup call to remain
1989 * within the time time source all along. We believe it
1990 * is cleaner and simpler to understand.
1992 if (is_cgroup_event(event))
1993 perf_cgroup_set_shadow_time(event, tstamp);
1995 event->shadow_ctx_time = tstamp - ctx->timestamp;
1998 #define MAX_INTERRUPTS (~0ULL)
2000 static void perf_log_throttle(struct perf_event *event, int enable);
2001 static void perf_log_itrace_start(struct perf_event *event);
2004 event_sched_in(struct perf_event *event,
2005 struct perf_cpu_context *cpuctx,
2006 struct perf_event_context *ctx)
2008 u64 tstamp = perf_event_time(event);
2011 lockdep_assert_held(&ctx->lock);
2013 if (event->state <= PERF_EVENT_STATE_OFF)
2016 WRITE_ONCE(event->oncpu, smp_processor_id());
2018 * Order event::oncpu write to happen before the ACTIVE state
2022 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2025 * Unthrottle events, since we scheduled we might have missed several
2026 * ticks already, also for a heavily scheduling task there is little
2027 * guarantee it'll get a tick in a timely manner.
2029 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2030 perf_log_throttle(event, 1);
2031 event->hw.interrupts = 0;
2035 * The new state must be visible before we turn it on in the hardware:
2039 perf_pmu_disable(event->pmu);
2041 perf_set_shadow_time(event, ctx, tstamp);
2043 perf_log_itrace_start(event);
2045 if (event->pmu->add(event, PERF_EF_START)) {
2046 event->state = PERF_EVENT_STATE_INACTIVE;
2052 event->tstamp_running += tstamp - event->tstamp_stopped;
2054 if (!is_software_event(event))
2055 cpuctx->active_oncpu++;
2056 if (!ctx->nr_active++)
2057 perf_event_ctx_activate(ctx);
2058 if (event->attr.freq && event->attr.sample_freq)
2061 if (event->attr.exclusive)
2062 cpuctx->exclusive = 1;
2065 perf_pmu_enable(event->pmu);
2071 group_sched_in(struct perf_event *group_event,
2072 struct perf_cpu_context *cpuctx,
2073 struct perf_event_context *ctx)
2075 struct perf_event *event, *partial_group = NULL;
2076 struct pmu *pmu = ctx->pmu;
2077 u64 now = ctx->time;
2078 bool simulate = false;
2080 if (group_event->state == PERF_EVENT_STATE_OFF)
2083 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2085 if (event_sched_in(group_event, cpuctx, ctx)) {
2086 pmu->cancel_txn(pmu);
2087 perf_mux_hrtimer_restart(cpuctx);
2092 * Schedule in siblings as one group (if any):
2094 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2095 if (event_sched_in(event, cpuctx, ctx)) {
2096 partial_group = event;
2101 if (!pmu->commit_txn(pmu))
2106 * Groups can be scheduled in as one unit only, so undo any
2107 * partial group before returning:
2108 * The events up to the failed event are scheduled out normally,
2109 * tstamp_stopped will be updated.
2111 * The failed events and the remaining siblings need to have
2112 * their timings updated as if they had gone thru event_sched_in()
2113 * and event_sched_out(). This is required to get consistent timings
2114 * across the group. This also takes care of the case where the group
2115 * could never be scheduled by ensuring tstamp_stopped is set to mark
2116 * the time the event was actually stopped, such that time delta
2117 * calculation in update_event_times() is correct.
2119 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2120 if (event == partial_group)
2124 event->tstamp_running += now - event->tstamp_stopped;
2125 event->tstamp_stopped = now;
2127 event_sched_out(event, cpuctx, ctx);
2130 event_sched_out(group_event, cpuctx, ctx);
2132 pmu->cancel_txn(pmu);
2134 perf_mux_hrtimer_restart(cpuctx);
2140 * Work out whether we can put this event group on the CPU now.
2142 static int group_can_go_on(struct perf_event *event,
2143 struct perf_cpu_context *cpuctx,
2147 * Groups consisting entirely of software events can always go on.
2149 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2152 * If an exclusive group is already on, no other hardware
2155 if (cpuctx->exclusive)
2158 * If this group is exclusive and there are already
2159 * events on the CPU, it can't go on.
2161 if (event->attr.exclusive && cpuctx->active_oncpu)
2164 * Otherwise, try to add it if all previous groups were able
2170 static void add_event_to_ctx(struct perf_event *event,
2171 struct perf_event_context *ctx)
2173 u64 tstamp = perf_event_time(event);
2175 list_add_event(event, ctx);
2176 perf_group_attach(event);
2177 event->tstamp_enabled = tstamp;
2178 event->tstamp_running = tstamp;
2179 event->tstamp_stopped = tstamp;
2182 static void ctx_sched_out(struct perf_event_context *ctx,
2183 struct perf_cpu_context *cpuctx,
2184 enum event_type_t event_type);
2186 ctx_sched_in(struct perf_event_context *ctx,
2187 struct perf_cpu_context *cpuctx,
2188 enum event_type_t event_type,
2189 struct task_struct *task);
2191 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2192 struct perf_event_context *ctx)
2194 if (!cpuctx->task_ctx)
2197 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2200 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2203 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2204 struct perf_event_context *ctx,
2205 struct task_struct *task)
2207 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2209 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2210 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2212 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2215 static void ctx_resched(struct perf_cpu_context *cpuctx,
2216 struct perf_event_context *task_ctx)
2218 perf_pmu_disable(cpuctx->ctx.pmu);
2220 task_ctx_sched_out(cpuctx, task_ctx);
2221 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2222 perf_event_sched_in(cpuctx, task_ctx, current);
2223 perf_pmu_enable(cpuctx->ctx.pmu);
2227 * Cross CPU call to install and enable a performance event
2229 * Very similar to remote_function() + event_function() but cannot assume that
2230 * things like ctx->is_active and cpuctx->task_ctx are set.
2232 static int __perf_install_in_context(void *info)
2234 struct perf_event *event = info;
2235 struct perf_event_context *ctx = event->ctx;
2236 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2237 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2238 bool activate = true;
2241 raw_spin_lock(&cpuctx->ctx.lock);
2243 raw_spin_lock(&ctx->lock);
2246 /* If we're on the wrong CPU, try again */
2247 if (task_cpu(ctx->task) != smp_processor_id()) {
2253 * If we're on the right CPU, see if the task we target is
2254 * current, if not we don't have to activate the ctx, a future
2255 * context switch will do that for us.
2257 if (ctx->task != current)
2260 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2262 } else if (task_ctx) {
2263 raw_spin_lock(&task_ctx->lock);
2267 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2268 add_event_to_ctx(event, ctx);
2269 ctx_resched(cpuctx, task_ctx);
2271 add_event_to_ctx(event, ctx);
2275 perf_ctx_unlock(cpuctx, task_ctx);
2281 * Attach a performance event to a context.
2283 * Very similar to event_function_call, see comment there.
2286 perf_install_in_context(struct perf_event_context *ctx,
2287 struct perf_event *event,
2290 struct task_struct *task = READ_ONCE(ctx->task);
2292 lockdep_assert_held(&ctx->mutex);
2294 if (event->cpu != -1)
2298 * Ensures that if we can observe event->ctx, both the event and ctx
2299 * will be 'complete'. See perf_iterate_sb_cpu().
2301 smp_store_release(&event->ctx, ctx);
2304 cpu_function_call(cpu, __perf_install_in_context, event);
2309 * Should not happen, we validate the ctx is still alive before calling.
2311 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2315 * Installing events is tricky because we cannot rely on ctx->is_active
2316 * to be set in case this is the nr_events 0 -> 1 transition.
2320 * Cannot use task_function_call() because we need to run on the task's
2321 * CPU regardless of whether its current or not.
2323 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event))
2326 raw_spin_lock_irq(&ctx->lock);
2328 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2330 * Cannot happen because we already checked above (which also
2331 * cannot happen), and we hold ctx->mutex, which serializes us
2332 * against perf_event_exit_task_context().
2334 raw_spin_unlock_irq(&ctx->lock);
2337 raw_spin_unlock_irq(&ctx->lock);
2339 * Since !ctx->is_active doesn't mean anything, we must IPI
2346 * Put a event into inactive state and update time fields.
2347 * Enabling the leader of a group effectively enables all
2348 * the group members that aren't explicitly disabled, so we
2349 * have to update their ->tstamp_enabled also.
2350 * Note: this works for group members as well as group leaders
2351 * since the non-leader members' sibling_lists will be empty.
2353 static void __perf_event_mark_enabled(struct perf_event *event)
2355 struct perf_event *sub;
2356 u64 tstamp = perf_event_time(event);
2358 event->state = PERF_EVENT_STATE_INACTIVE;
2359 event->tstamp_enabled = tstamp - event->total_time_enabled;
2360 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2361 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2362 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2367 * Cross CPU call to enable a performance event
2369 static void __perf_event_enable(struct perf_event *event,
2370 struct perf_cpu_context *cpuctx,
2371 struct perf_event_context *ctx,
2374 struct perf_event *leader = event->group_leader;
2375 struct perf_event_context *task_ctx;
2377 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2378 event->state <= PERF_EVENT_STATE_ERROR)
2382 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2384 __perf_event_mark_enabled(event);
2386 if (!ctx->is_active)
2389 if (!event_filter_match(event)) {
2390 if (is_cgroup_event(event))
2391 perf_cgroup_defer_enabled(event);
2392 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2397 * If the event is in a group and isn't the group leader,
2398 * then don't put it on unless the group is on.
2400 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2401 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2405 task_ctx = cpuctx->task_ctx;
2407 WARN_ON_ONCE(task_ctx != ctx);
2409 ctx_resched(cpuctx, task_ctx);
2415 * If event->ctx is a cloned context, callers must make sure that
2416 * every task struct that event->ctx->task could possibly point to
2417 * remains valid. This condition is satisfied when called through
2418 * perf_event_for_each_child or perf_event_for_each as described
2419 * for perf_event_disable.
2421 static void _perf_event_enable(struct perf_event *event)
2423 struct perf_event_context *ctx = event->ctx;
2425 raw_spin_lock_irq(&ctx->lock);
2426 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2427 event->state < PERF_EVENT_STATE_ERROR) {
2428 raw_spin_unlock_irq(&ctx->lock);
2433 * If the event is in error state, clear that first.
2435 * That way, if we see the event in error state below, we know that it
2436 * has gone back into error state, as distinct from the task having
2437 * been scheduled away before the cross-call arrived.
2439 if (event->state == PERF_EVENT_STATE_ERROR)
2440 event->state = PERF_EVENT_STATE_OFF;
2441 raw_spin_unlock_irq(&ctx->lock);
2443 event_function_call(event, __perf_event_enable, NULL);
2447 * See perf_event_disable();
2449 void perf_event_enable(struct perf_event *event)
2451 struct perf_event_context *ctx;
2453 ctx = perf_event_ctx_lock(event);
2454 _perf_event_enable(event);
2455 perf_event_ctx_unlock(event, ctx);
2457 EXPORT_SYMBOL_GPL(perf_event_enable);
2459 struct stop_event_data {
2460 struct perf_event *event;
2461 unsigned int restart;
2464 static int __perf_event_stop(void *info)
2466 struct stop_event_data *sd = info;
2467 struct perf_event *event = sd->event;
2469 /* if it's already INACTIVE, do nothing */
2470 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2473 /* matches smp_wmb() in event_sched_in() */
2477 * There is a window with interrupts enabled before we get here,
2478 * so we need to check again lest we try to stop another CPU's event.
2480 if (READ_ONCE(event->oncpu) != smp_processor_id())
2483 event->pmu->stop(event, PERF_EF_UPDATE);
2486 * May race with the actual stop (through perf_pmu_output_stop()),
2487 * but it is only used for events with AUX ring buffer, and such
2488 * events will refuse to restart because of rb::aux_mmap_count==0,
2489 * see comments in perf_aux_output_begin().
2491 * Since this is happening on a event-local CPU, no trace is lost
2495 event->pmu->start(event, PERF_EF_START);
2500 static int perf_event_restart(struct perf_event *event)
2502 struct stop_event_data sd = {
2509 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2512 /* matches smp_wmb() in event_sched_in() */
2516 * We only want to restart ACTIVE events, so if the event goes
2517 * inactive here (event->oncpu==-1), there's nothing more to do;
2518 * fall through with ret==-ENXIO.
2520 ret = cpu_function_call(READ_ONCE(event->oncpu),
2521 __perf_event_stop, &sd);
2522 } while (ret == -EAGAIN);
2528 * In order to contain the amount of racy and tricky in the address filter
2529 * configuration management, it is a two part process:
2531 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2532 * we update the addresses of corresponding vmas in
2533 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2534 * (p2) when an event is scheduled in (pmu::add), it calls
2535 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2536 * if the generation has changed since the previous call.
2538 * If (p1) happens while the event is active, we restart it to force (p2).
2540 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2541 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2543 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2544 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2546 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2549 void perf_event_addr_filters_sync(struct perf_event *event)
2551 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2553 if (!has_addr_filter(event))
2556 raw_spin_lock(&ifh->lock);
2557 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2558 event->pmu->addr_filters_sync(event);
2559 event->hw.addr_filters_gen = event->addr_filters_gen;
2561 raw_spin_unlock(&ifh->lock);
2563 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2565 static int _perf_event_refresh(struct perf_event *event, int refresh)
2568 * not supported on inherited events
2570 if (event->attr.inherit || !is_sampling_event(event))
2573 atomic_add(refresh, &event->event_limit);
2574 _perf_event_enable(event);
2580 * See perf_event_disable()
2582 int perf_event_refresh(struct perf_event *event, int refresh)
2584 struct perf_event_context *ctx;
2587 ctx = perf_event_ctx_lock(event);
2588 ret = _perf_event_refresh(event, refresh);
2589 perf_event_ctx_unlock(event, ctx);
2593 EXPORT_SYMBOL_GPL(perf_event_refresh);
2595 static void ctx_sched_out(struct perf_event_context *ctx,
2596 struct perf_cpu_context *cpuctx,
2597 enum event_type_t event_type)
2599 int is_active = ctx->is_active;
2600 struct perf_event *event;
2602 lockdep_assert_held(&ctx->lock);
2604 if (likely(!ctx->nr_events)) {
2606 * See __perf_remove_from_context().
2608 WARN_ON_ONCE(ctx->is_active);
2610 WARN_ON_ONCE(cpuctx->task_ctx);
2614 ctx->is_active &= ~event_type;
2615 if (!(ctx->is_active & EVENT_ALL))
2619 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2620 if (!ctx->is_active)
2621 cpuctx->task_ctx = NULL;
2625 * Always update time if it was set; not only when it changes.
2626 * Otherwise we can 'forget' to update time for any but the last
2627 * context we sched out. For example:
2629 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2630 * ctx_sched_out(.event_type = EVENT_PINNED)
2632 * would only update time for the pinned events.
2634 if (is_active & EVENT_TIME) {
2635 /* update (and stop) ctx time */
2636 update_context_time(ctx);
2637 update_cgrp_time_from_cpuctx(cpuctx);
2640 is_active ^= ctx->is_active; /* changed bits */
2642 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2645 perf_pmu_disable(ctx->pmu);
2646 if (is_active & EVENT_PINNED) {
2647 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2648 group_sched_out(event, cpuctx, ctx);
2651 if (is_active & EVENT_FLEXIBLE) {
2652 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2653 group_sched_out(event, cpuctx, ctx);
2655 perf_pmu_enable(ctx->pmu);
2659 * Test whether two contexts are equivalent, i.e. whether they have both been
2660 * cloned from the same version of the same context.
2662 * Equivalence is measured using a generation number in the context that is
2663 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2664 * and list_del_event().
2666 static int context_equiv(struct perf_event_context *ctx1,
2667 struct perf_event_context *ctx2)
2669 lockdep_assert_held(&ctx1->lock);
2670 lockdep_assert_held(&ctx2->lock);
2672 /* Pinning disables the swap optimization */
2673 if (ctx1->pin_count || ctx2->pin_count)
2676 /* If ctx1 is the parent of ctx2 */
2677 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2680 /* If ctx2 is the parent of ctx1 */
2681 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2685 * If ctx1 and ctx2 have the same parent; we flatten the parent
2686 * hierarchy, see perf_event_init_context().
2688 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2689 ctx1->parent_gen == ctx2->parent_gen)
2696 static void __perf_event_sync_stat(struct perf_event *event,
2697 struct perf_event *next_event)
2701 if (!event->attr.inherit_stat)
2705 * Update the event value, we cannot use perf_event_read()
2706 * because we're in the middle of a context switch and have IRQs
2707 * disabled, which upsets smp_call_function_single(), however
2708 * we know the event must be on the current CPU, therefore we
2709 * don't need to use it.
2711 switch (event->state) {
2712 case PERF_EVENT_STATE_ACTIVE:
2713 event->pmu->read(event);
2716 case PERF_EVENT_STATE_INACTIVE:
2717 update_event_times(event);
2725 * In order to keep per-task stats reliable we need to flip the event
2726 * values when we flip the contexts.
2728 value = local64_read(&next_event->count);
2729 value = local64_xchg(&event->count, value);
2730 local64_set(&next_event->count, value);
2732 swap(event->total_time_enabled, next_event->total_time_enabled);
2733 swap(event->total_time_running, next_event->total_time_running);
2736 * Since we swizzled the values, update the user visible data too.
2738 perf_event_update_userpage(event);
2739 perf_event_update_userpage(next_event);
2742 static void perf_event_sync_stat(struct perf_event_context *ctx,
2743 struct perf_event_context *next_ctx)
2745 struct perf_event *event, *next_event;
2750 update_context_time(ctx);
2752 event = list_first_entry(&ctx->event_list,
2753 struct perf_event, event_entry);
2755 next_event = list_first_entry(&next_ctx->event_list,
2756 struct perf_event, event_entry);
2758 while (&event->event_entry != &ctx->event_list &&
2759 &next_event->event_entry != &next_ctx->event_list) {
2761 __perf_event_sync_stat(event, next_event);
2763 event = list_next_entry(event, event_entry);
2764 next_event = list_next_entry(next_event, event_entry);
2768 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2769 struct task_struct *next)
2771 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2772 struct perf_event_context *next_ctx;
2773 struct perf_event_context *parent, *next_parent;
2774 struct perf_cpu_context *cpuctx;
2780 cpuctx = __get_cpu_context(ctx);
2781 if (!cpuctx->task_ctx)
2785 next_ctx = next->perf_event_ctxp[ctxn];
2789 parent = rcu_dereference(ctx->parent_ctx);
2790 next_parent = rcu_dereference(next_ctx->parent_ctx);
2792 /* If neither context have a parent context; they cannot be clones. */
2793 if (!parent && !next_parent)
2796 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2798 * Looks like the two contexts are clones, so we might be
2799 * able to optimize the context switch. We lock both
2800 * contexts and check that they are clones under the
2801 * lock (including re-checking that neither has been
2802 * uncloned in the meantime). It doesn't matter which
2803 * order we take the locks because no other cpu could
2804 * be trying to lock both of these tasks.
2806 raw_spin_lock(&ctx->lock);
2807 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2808 if (context_equiv(ctx, next_ctx)) {
2809 WRITE_ONCE(ctx->task, next);
2810 WRITE_ONCE(next_ctx->task, task);
2812 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2815 * RCU_INIT_POINTER here is safe because we've not
2816 * modified the ctx and the above modification of
2817 * ctx->task and ctx->task_ctx_data are immaterial
2818 * since those values are always verified under
2819 * ctx->lock which we're now holding.
2821 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2822 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2826 perf_event_sync_stat(ctx, next_ctx);
2828 raw_spin_unlock(&next_ctx->lock);
2829 raw_spin_unlock(&ctx->lock);
2835 raw_spin_lock(&ctx->lock);
2836 task_ctx_sched_out(cpuctx, ctx);
2837 raw_spin_unlock(&ctx->lock);
2841 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2843 void perf_sched_cb_dec(struct pmu *pmu)
2845 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2847 this_cpu_dec(perf_sched_cb_usages);
2849 if (!--cpuctx->sched_cb_usage)
2850 list_del(&cpuctx->sched_cb_entry);
2854 void perf_sched_cb_inc(struct pmu *pmu)
2856 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2858 if (!cpuctx->sched_cb_usage++)
2859 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2861 this_cpu_inc(perf_sched_cb_usages);
2865 * This function provides the context switch callback to the lower code
2866 * layer. It is invoked ONLY when the context switch callback is enabled.
2868 * This callback is relevant even to per-cpu events; for example multi event
2869 * PEBS requires this to provide PID/TID information. This requires we flush
2870 * all queued PEBS records before we context switch to a new task.
2872 static void perf_pmu_sched_task(struct task_struct *prev,
2873 struct task_struct *next,
2876 struct perf_cpu_context *cpuctx;
2882 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2883 pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */
2885 if (WARN_ON_ONCE(!pmu->sched_task))
2888 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2889 perf_pmu_disable(pmu);
2891 pmu->sched_task(cpuctx->task_ctx, sched_in);
2893 perf_pmu_enable(pmu);
2894 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2898 static void perf_event_switch(struct task_struct *task,
2899 struct task_struct *next_prev, bool sched_in);
2901 #define for_each_task_context_nr(ctxn) \
2902 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2905 * Called from scheduler to remove the events of the current task,
2906 * with interrupts disabled.
2908 * We stop each event and update the event value in event->count.
2910 * This does not protect us against NMI, but disable()
2911 * sets the disabled bit in the control field of event _before_
2912 * accessing the event control register. If a NMI hits, then it will
2913 * not restart the event.
2915 void __perf_event_task_sched_out(struct task_struct *task,
2916 struct task_struct *next)
2920 if (__this_cpu_read(perf_sched_cb_usages))
2921 perf_pmu_sched_task(task, next, false);
2923 if (atomic_read(&nr_switch_events))
2924 perf_event_switch(task, next, false);
2926 for_each_task_context_nr(ctxn)
2927 perf_event_context_sched_out(task, ctxn, next);
2930 * if cgroup events exist on this CPU, then we need
2931 * to check if we have to switch out PMU state.
2932 * cgroup event are system-wide mode only
2934 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2935 perf_cgroup_sched_out(task, next);
2939 * Called with IRQs disabled
2941 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2942 enum event_type_t event_type)
2944 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2948 ctx_pinned_sched_in(struct perf_event_context *ctx,
2949 struct perf_cpu_context *cpuctx)
2951 struct perf_event *event;
2953 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2954 if (event->state <= PERF_EVENT_STATE_OFF)
2956 if (!event_filter_match(event))
2959 /* may need to reset tstamp_enabled */
2960 if (is_cgroup_event(event))
2961 perf_cgroup_mark_enabled(event, ctx);
2963 if (group_can_go_on(event, cpuctx, 1))
2964 group_sched_in(event, cpuctx, ctx);
2967 * If this pinned group hasn't been scheduled,
2968 * put it in error state.
2970 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2971 update_group_times(event);
2972 event->state = PERF_EVENT_STATE_ERROR;
2978 ctx_flexible_sched_in(struct perf_event_context *ctx,
2979 struct perf_cpu_context *cpuctx)
2981 struct perf_event *event;
2984 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2985 /* Ignore events in OFF or ERROR state */
2986 if (event->state <= PERF_EVENT_STATE_OFF)
2989 * Listen to the 'cpu' scheduling filter constraint
2992 if (!event_filter_match(event))
2995 /* may need to reset tstamp_enabled */
2996 if (is_cgroup_event(event))
2997 perf_cgroup_mark_enabled(event, ctx);
2999 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3000 if (group_sched_in(event, cpuctx, ctx))
3007 ctx_sched_in(struct perf_event_context *ctx,
3008 struct perf_cpu_context *cpuctx,
3009 enum event_type_t event_type,
3010 struct task_struct *task)
3012 int is_active = ctx->is_active;
3015 lockdep_assert_held(&ctx->lock);
3017 if (likely(!ctx->nr_events))
3020 ctx->is_active |= (event_type | EVENT_TIME);
3023 cpuctx->task_ctx = ctx;
3025 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3028 is_active ^= ctx->is_active; /* changed bits */
3030 if (is_active & EVENT_TIME) {
3031 /* start ctx time */
3033 ctx->timestamp = now;
3034 perf_cgroup_set_timestamp(task, ctx);
3038 * First go through the list and put on any pinned groups
3039 * in order to give them the best chance of going on.
3041 if (is_active & EVENT_PINNED)
3042 ctx_pinned_sched_in(ctx, cpuctx);
3044 /* Then walk through the lower prio flexible groups */
3045 if (is_active & EVENT_FLEXIBLE)
3046 ctx_flexible_sched_in(ctx, cpuctx);
3049 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3050 enum event_type_t event_type,
3051 struct task_struct *task)
3053 struct perf_event_context *ctx = &cpuctx->ctx;
3055 ctx_sched_in(ctx, cpuctx, event_type, task);
3058 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3059 struct task_struct *task)
3061 struct perf_cpu_context *cpuctx;
3063 cpuctx = __get_cpu_context(ctx);
3064 if (cpuctx->task_ctx == ctx)
3067 perf_ctx_lock(cpuctx, ctx);
3068 perf_pmu_disable(ctx->pmu);
3070 * We want to keep the following priority order:
3071 * cpu pinned (that don't need to move), task pinned,
3072 * cpu flexible, task flexible.
3074 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3075 perf_event_sched_in(cpuctx, ctx, task);
3076 perf_pmu_enable(ctx->pmu);
3077 perf_ctx_unlock(cpuctx, ctx);
3081 * Called from scheduler to add the events of the current task
3082 * with interrupts disabled.
3084 * We restore the event value and then enable it.
3086 * This does not protect us against NMI, but enable()
3087 * sets the enabled bit in the control field of event _before_
3088 * accessing the event control register. If a NMI hits, then it will
3089 * keep the event running.
3091 void __perf_event_task_sched_in(struct task_struct *prev,
3092 struct task_struct *task)
3094 struct perf_event_context *ctx;
3098 * If cgroup events exist on this CPU, then we need to check if we have
3099 * to switch in PMU state; cgroup event are system-wide mode only.
3101 * Since cgroup events are CPU events, we must schedule these in before
3102 * we schedule in the task events.
3104 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3105 perf_cgroup_sched_in(prev, task);
3107 for_each_task_context_nr(ctxn) {
3108 ctx = task->perf_event_ctxp[ctxn];
3112 perf_event_context_sched_in(ctx, task);
3115 if (atomic_read(&nr_switch_events))
3116 perf_event_switch(task, prev, true);
3118 if (__this_cpu_read(perf_sched_cb_usages))
3119 perf_pmu_sched_task(prev, task, true);
3122 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3124 u64 frequency = event->attr.sample_freq;
3125 u64 sec = NSEC_PER_SEC;
3126 u64 divisor, dividend;
3128 int count_fls, nsec_fls, frequency_fls, sec_fls;
3130 count_fls = fls64(count);
3131 nsec_fls = fls64(nsec);
3132 frequency_fls = fls64(frequency);
3136 * We got @count in @nsec, with a target of sample_freq HZ
3137 * the target period becomes:
3140 * period = -------------------
3141 * @nsec * sample_freq
3146 * Reduce accuracy by one bit such that @a and @b converge
3147 * to a similar magnitude.
3149 #define REDUCE_FLS(a, b) \
3151 if (a##_fls > b##_fls) { \
3161 * Reduce accuracy until either term fits in a u64, then proceed with
3162 * the other, so that finally we can do a u64/u64 division.
3164 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3165 REDUCE_FLS(nsec, frequency);
3166 REDUCE_FLS(sec, count);
3169 if (count_fls + sec_fls > 64) {
3170 divisor = nsec * frequency;
3172 while (count_fls + sec_fls > 64) {
3173 REDUCE_FLS(count, sec);
3177 dividend = count * sec;
3179 dividend = count * sec;
3181 while (nsec_fls + frequency_fls > 64) {
3182 REDUCE_FLS(nsec, frequency);
3186 divisor = nsec * frequency;
3192 return div64_u64(dividend, divisor);
3195 static DEFINE_PER_CPU(int, perf_throttled_count);
3196 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3198 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3200 struct hw_perf_event *hwc = &event->hw;
3201 s64 period, sample_period;
3204 period = perf_calculate_period(event, nsec, count);
3206 delta = (s64)(period - hwc->sample_period);
3207 delta = (delta + 7) / 8; /* low pass filter */
3209 sample_period = hwc->sample_period + delta;
3214 hwc->sample_period = sample_period;
3216 if (local64_read(&hwc->period_left) > 8*sample_period) {
3218 event->pmu->stop(event, PERF_EF_UPDATE);
3220 local64_set(&hwc->period_left, 0);
3223 event->pmu->start(event, PERF_EF_RELOAD);
3228 * combine freq adjustment with unthrottling to avoid two passes over the
3229 * events. At the same time, make sure, having freq events does not change
3230 * the rate of unthrottling as that would introduce bias.
3232 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3235 struct perf_event *event;
3236 struct hw_perf_event *hwc;
3237 u64 now, period = TICK_NSEC;
3241 * only need to iterate over all events iff:
3242 * - context have events in frequency mode (needs freq adjust)
3243 * - there are events to unthrottle on this cpu
3245 if (!(ctx->nr_freq || needs_unthr))
3248 raw_spin_lock(&ctx->lock);
3249 perf_pmu_disable(ctx->pmu);
3251 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3252 if (event->state != PERF_EVENT_STATE_ACTIVE)
3255 if (!event_filter_match(event))
3258 perf_pmu_disable(event->pmu);
3262 if (hwc->interrupts == MAX_INTERRUPTS) {
3263 hwc->interrupts = 0;
3264 perf_log_throttle(event, 1);
3265 event->pmu->start(event, 0);
3268 if (!event->attr.freq || !event->attr.sample_freq)
3272 * stop the event and update event->count
3274 event->pmu->stop(event, PERF_EF_UPDATE);
3276 now = local64_read(&event->count);
3277 delta = now - hwc->freq_count_stamp;
3278 hwc->freq_count_stamp = now;
3282 * reload only if value has changed
3283 * we have stopped the event so tell that
3284 * to perf_adjust_period() to avoid stopping it
3288 perf_adjust_period(event, period, delta, false);
3290 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3292 perf_pmu_enable(event->pmu);
3295 perf_pmu_enable(ctx->pmu);
3296 raw_spin_unlock(&ctx->lock);
3300 * Round-robin a context's events:
3302 static void rotate_ctx(struct perf_event_context *ctx)
3305 * Rotate the first entry last of non-pinned groups. Rotation might be
3306 * disabled by the inheritance code.
3308 if (!ctx->rotate_disable)
3309 list_rotate_left(&ctx->flexible_groups);
3312 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3314 struct perf_event_context *ctx = NULL;
3317 if (cpuctx->ctx.nr_events) {
3318 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3322 ctx = cpuctx->task_ctx;
3323 if (ctx && ctx->nr_events) {
3324 if (ctx->nr_events != ctx->nr_active)
3331 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3332 perf_pmu_disable(cpuctx->ctx.pmu);
3334 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3336 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3338 rotate_ctx(&cpuctx->ctx);
3342 perf_event_sched_in(cpuctx, ctx, current);
3344 perf_pmu_enable(cpuctx->ctx.pmu);
3345 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3351 void perf_event_task_tick(void)
3353 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3354 struct perf_event_context *ctx, *tmp;
3357 WARN_ON(!irqs_disabled());
3359 __this_cpu_inc(perf_throttled_seq);
3360 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3361 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3363 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3364 perf_adjust_freq_unthr_context(ctx, throttled);
3367 static int event_enable_on_exec(struct perf_event *event,
3368 struct perf_event_context *ctx)
3370 if (!event->attr.enable_on_exec)
3373 event->attr.enable_on_exec = 0;
3374 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3377 __perf_event_mark_enabled(event);
3383 * Enable all of a task's events that have been marked enable-on-exec.
3384 * This expects task == current.
3386 static void perf_event_enable_on_exec(int ctxn)
3388 struct perf_event_context *ctx, *clone_ctx = NULL;
3389 struct perf_cpu_context *cpuctx;
3390 struct perf_event *event;
3391 unsigned long flags;
3394 local_irq_save(flags);
3395 ctx = current->perf_event_ctxp[ctxn];
3396 if (!ctx || !ctx->nr_events)
3399 cpuctx = __get_cpu_context(ctx);
3400 perf_ctx_lock(cpuctx, ctx);
3401 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3402 list_for_each_entry(event, &ctx->event_list, event_entry)
3403 enabled |= event_enable_on_exec(event, ctx);
3406 * Unclone and reschedule this context if we enabled any event.
3409 clone_ctx = unclone_ctx(ctx);
3410 ctx_resched(cpuctx, ctx);
3412 perf_ctx_unlock(cpuctx, ctx);
3415 local_irq_restore(flags);
3421 struct perf_read_data {
3422 struct perf_event *event;
3427 static int find_cpu_to_read(struct perf_event *event, int local_cpu)
3429 int event_cpu = event->oncpu;
3430 u16 local_pkg, event_pkg;
3432 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3433 event_pkg = topology_physical_package_id(event_cpu);
3434 local_pkg = topology_physical_package_id(local_cpu);
3436 if (event_pkg == local_pkg)
3444 * Cross CPU call to read the hardware event
3446 static void __perf_event_read(void *info)
3448 struct perf_read_data *data = info;
3449 struct perf_event *sub, *event = data->event;
3450 struct perf_event_context *ctx = event->ctx;
3451 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3452 struct pmu *pmu = event->pmu;
3455 * If this is a task context, we need to check whether it is
3456 * the current task context of this cpu. If not it has been
3457 * scheduled out before the smp call arrived. In that case
3458 * event->count would have been updated to a recent sample
3459 * when the event was scheduled out.
3461 if (ctx->task && cpuctx->task_ctx != ctx)
3464 raw_spin_lock(&ctx->lock);
3465 if (ctx->is_active) {
3466 update_context_time(ctx);
3467 update_cgrp_time_from_event(event);
3470 update_event_times(event);
3471 if (event->state != PERF_EVENT_STATE_ACTIVE)
3480 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3484 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3485 update_event_times(sub);
3486 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3488 * Use sibling's PMU rather than @event's since
3489 * sibling could be on different (eg: software) PMU.
3491 sub->pmu->read(sub);
3495 data->ret = pmu->commit_txn(pmu);
3498 raw_spin_unlock(&ctx->lock);
3501 static inline u64 perf_event_count(struct perf_event *event)
3503 if (event->pmu->count)
3504 return event->pmu->count(event);
3506 return __perf_event_count(event);
3510 * NMI-safe method to read a local event, that is an event that
3512 * - either for the current task, or for this CPU
3513 * - does not have inherit set, for inherited task events
3514 * will not be local and we cannot read them atomically
3515 * - must not have a pmu::count method
3517 u64 perf_event_read_local(struct perf_event *event)
3519 unsigned long flags;
3523 * Disabling interrupts avoids all counter scheduling (context
3524 * switches, timer based rotation and IPIs).
3526 local_irq_save(flags);
3528 /* If this is a per-task event, it must be for current */
3529 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3530 event->hw.target != current);
3532 /* If this is a per-CPU event, it must be for this CPU */
3533 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3534 event->cpu != smp_processor_id());
3537 * It must not be an event with inherit set, we cannot read
3538 * all child counters from atomic context.
3540 WARN_ON_ONCE(event->attr.inherit);
3543 * It must not have a pmu::count method, those are not
3546 WARN_ON_ONCE(event->pmu->count);
3549 * If the event is currently on this CPU, its either a per-task event,
3550 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3553 if (event->oncpu == smp_processor_id())
3554 event->pmu->read(event);
3556 val = local64_read(&event->count);
3557 local_irq_restore(flags);
3562 static int perf_event_read(struct perf_event *event, bool group)
3564 int ret = 0, cpu_to_read, local_cpu;
3567 * If event is enabled and currently active on a CPU, update the
3568 * value in the event structure:
3570 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3571 struct perf_read_data data = {
3577 local_cpu = get_cpu();
3578 cpu_to_read = find_cpu_to_read(event, local_cpu);
3581 ret = smp_call_function_single(cpu_to_read, __perf_event_read, &data, 1);
3582 /* The event must have been read from an online CPU: */
3584 ret = ret ? : data.ret;
3585 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3586 struct perf_event_context *ctx = event->ctx;
3587 unsigned long flags;
3589 raw_spin_lock_irqsave(&ctx->lock, flags);
3591 * may read while context is not active
3592 * (e.g., thread is blocked), in that case
3593 * we cannot update context time
3595 if (ctx->is_active) {
3596 update_context_time(ctx);
3597 update_cgrp_time_from_event(event);
3600 update_group_times(event);
3602 update_event_times(event);
3603 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3610 * Initialize the perf_event context in a task_struct:
3612 static void __perf_event_init_context(struct perf_event_context *ctx)
3614 raw_spin_lock_init(&ctx->lock);
3615 mutex_init(&ctx->mutex);
3616 INIT_LIST_HEAD(&ctx->active_ctx_list);
3617 INIT_LIST_HEAD(&ctx->pinned_groups);
3618 INIT_LIST_HEAD(&ctx->flexible_groups);
3619 INIT_LIST_HEAD(&ctx->event_list);
3620 atomic_set(&ctx->refcount, 1);
3623 static struct perf_event_context *
3624 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3626 struct perf_event_context *ctx;
3628 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3632 __perf_event_init_context(ctx);
3635 get_task_struct(task);
3642 static struct task_struct *
3643 find_lively_task_by_vpid(pid_t vpid)
3645 struct task_struct *task;
3651 task = find_task_by_vpid(vpid);
3653 get_task_struct(task);
3657 return ERR_PTR(-ESRCH);
3663 * Returns a matching context with refcount and pincount.
3665 static struct perf_event_context *
3666 find_get_context(struct pmu *pmu, struct task_struct *task,
3667 struct perf_event *event)
3669 struct perf_event_context *ctx, *clone_ctx = NULL;
3670 struct perf_cpu_context *cpuctx;
3671 void *task_ctx_data = NULL;
3672 unsigned long flags;
3674 int cpu = event->cpu;
3677 /* Must be root to operate on a CPU event: */
3678 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3679 return ERR_PTR(-EACCES);
3682 * We could be clever and allow to attach a event to an
3683 * offline CPU and activate it when the CPU comes up, but
3686 if (!cpu_online(cpu))
3687 return ERR_PTR(-ENODEV);
3689 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3698 ctxn = pmu->task_ctx_nr;
3702 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3703 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3704 if (!task_ctx_data) {
3711 ctx = perf_lock_task_context(task, ctxn, &flags);
3713 clone_ctx = unclone_ctx(ctx);
3716 if (task_ctx_data && !ctx->task_ctx_data) {
3717 ctx->task_ctx_data = task_ctx_data;
3718 task_ctx_data = NULL;
3720 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3725 ctx = alloc_perf_context(pmu, task);
3730 if (task_ctx_data) {
3731 ctx->task_ctx_data = task_ctx_data;
3732 task_ctx_data = NULL;
3736 mutex_lock(&task->perf_event_mutex);
3738 * If it has already passed perf_event_exit_task().
3739 * we must see PF_EXITING, it takes this mutex too.
3741 if (task->flags & PF_EXITING)
3743 else if (task->perf_event_ctxp[ctxn])
3748 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3750 mutex_unlock(&task->perf_event_mutex);
3752 if (unlikely(err)) {
3761 kfree(task_ctx_data);
3765 kfree(task_ctx_data);
3766 return ERR_PTR(err);
3769 static void perf_event_free_filter(struct perf_event *event);
3770 static void perf_event_free_bpf_prog(struct perf_event *event);
3772 static void free_event_rcu(struct rcu_head *head)
3774 struct perf_event *event;
3776 event = container_of(head, struct perf_event, rcu_head);
3778 put_pid_ns(event->ns);
3779 perf_event_free_filter(event);
3783 static void ring_buffer_attach(struct perf_event *event,
3784 struct ring_buffer *rb);
3786 static void detach_sb_event(struct perf_event *event)
3788 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3790 raw_spin_lock(&pel->lock);
3791 list_del_rcu(&event->sb_list);
3792 raw_spin_unlock(&pel->lock);
3795 static bool is_sb_event(struct perf_event *event)
3797 struct perf_event_attr *attr = &event->attr;
3802 if (event->attach_state & PERF_ATTACH_TASK)
3805 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3806 attr->comm || attr->comm_exec ||
3808 attr->context_switch)
3813 static void unaccount_pmu_sb_event(struct perf_event *event)
3815 if (is_sb_event(event))
3816 detach_sb_event(event);
3819 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3824 if (is_cgroup_event(event))
3825 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3828 #ifdef CONFIG_NO_HZ_FULL
3829 static DEFINE_SPINLOCK(nr_freq_lock);
3832 static void unaccount_freq_event_nohz(void)
3834 #ifdef CONFIG_NO_HZ_FULL
3835 spin_lock(&nr_freq_lock);
3836 if (atomic_dec_and_test(&nr_freq_events))
3837 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3838 spin_unlock(&nr_freq_lock);
3842 static void unaccount_freq_event(void)
3844 if (tick_nohz_full_enabled())
3845 unaccount_freq_event_nohz();
3847 atomic_dec(&nr_freq_events);
3850 static void unaccount_event(struct perf_event *event)
3857 if (event->attach_state & PERF_ATTACH_TASK)
3859 if (event->attr.mmap || event->attr.mmap_data)
3860 atomic_dec(&nr_mmap_events);
3861 if (event->attr.comm)
3862 atomic_dec(&nr_comm_events);
3863 if (event->attr.task)
3864 atomic_dec(&nr_task_events);
3865 if (event->attr.freq)
3866 unaccount_freq_event();
3867 if (event->attr.context_switch) {
3869 atomic_dec(&nr_switch_events);
3871 if (is_cgroup_event(event))
3873 if (has_branch_stack(event))
3877 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3878 schedule_delayed_work(&perf_sched_work, HZ);
3881 unaccount_event_cpu(event, event->cpu);
3883 unaccount_pmu_sb_event(event);
3886 static void perf_sched_delayed(struct work_struct *work)
3888 mutex_lock(&perf_sched_mutex);
3889 if (atomic_dec_and_test(&perf_sched_count))
3890 static_branch_disable(&perf_sched_events);
3891 mutex_unlock(&perf_sched_mutex);
3895 * The following implement mutual exclusion of events on "exclusive" pmus
3896 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3897 * at a time, so we disallow creating events that might conflict, namely:
3899 * 1) cpu-wide events in the presence of per-task events,
3900 * 2) per-task events in the presence of cpu-wide events,
3901 * 3) two matching events on the same context.
3903 * The former two cases are handled in the allocation path (perf_event_alloc(),
3904 * _free_event()), the latter -- before the first perf_install_in_context().
3906 static int exclusive_event_init(struct perf_event *event)
3908 struct pmu *pmu = event->pmu;
3910 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3914 * Prevent co-existence of per-task and cpu-wide events on the
3915 * same exclusive pmu.
3917 * Negative pmu::exclusive_cnt means there are cpu-wide
3918 * events on this "exclusive" pmu, positive means there are
3921 * Since this is called in perf_event_alloc() path, event::ctx
3922 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3923 * to mean "per-task event", because unlike other attach states it
3924 * never gets cleared.
3926 if (event->attach_state & PERF_ATTACH_TASK) {
3927 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3930 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3937 static void exclusive_event_destroy(struct perf_event *event)
3939 struct pmu *pmu = event->pmu;
3941 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3944 /* see comment in exclusive_event_init() */
3945 if (event->attach_state & PERF_ATTACH_TASK)
3946 atomic_dec(&pmu->exclusive_cnt);
3948 atomic_inc(&pmu->exclusive_cnt);
3951 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3953 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3954 (e1->cpu == e2->cpu ||
3961 /* Called under the same ctx::mutex as perf_install_in_context() */
3962 static bool exclusive_event_installable(struct perf_event *event,
3963 struct perf_event_context *ctx)
3965 struct perf_event *iter_event;
3966 struct pmu *pmu = event->pmu;
3968 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3971 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3972 if (exclusive_event_match(iter_event, event))
3979 static void perf_addr_filters_splice(struct perf_event *event,
3980 struct list_head *head);
3982 static void _free_event(struct perf_event *event)
3984 irq_work_sync(&event->pending);
3986 unaccount_event(event);
3990 * Can happen when we close an event with re-directed output.
3992 * Since we have a 0 refcount, perf_mmap_close() will skip
3993 * over us; possibly making our ring_buffer_put() the last.
3995 mutex_lock(&event->mmap_mutex);
3996 ring_buffer_attach(event, NULL);
3997 mutex_unlock(&event->mmap_mutex);
4000 if (is_cgroup_event(event))
4001 perf_detach_cgroup(event);
4003 if (!event->parent) {
4004 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4005 put_callchain_buffers();
4008 perf_event_free_bpf_prog(event);
4009 perf_addr_filters_splice(event, NULL);
4010 kfree(event->addr_filters_offs);
4013 event->destroy(event);
4016 put_ctx(event->ctx);
4018 exclusive_event_destroy(event);
4019 module_put(event->pmu->module);
4021 call_rcu(&event->rcu_head, free_event_rcu);
4025 * Used to free events which have a known refcount of 1, such as in error paths
4026 * where the event isn't exposed yet and inherited events.
4028 static void free_event(struct perf_event *event)
4030 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4031 "unexpected event refcount: %ld; ptr=%p\n",
4032 atomic_long_read(&event->refcount), event)) {
4033 /* leak to avoid use-after-free */
4041 * Remove user event from the owner task.
4043 static void perf_remove_from_owner(struct perf_event *event)
4045 struct task_struct *owner;
4049 * Matches the smp_store_release() in perf_event_exit_task(). If we
4050 * observe !owner it means the list deletion is complete and we can
4051 * indeed free this event, otherwise we need to serialize on
4052 * owner->perf_event_mutex.
4054 owner = lockless_dereference(event->owner);
4057 * Since delayed_put_task_struct() also drops the last
4058 * task reference we can safely take a new reference
4059 * while holding the rcu_read_lock().
4061 get_task_struct(owner);
4067 * If we're here through perf_event_exit_task() we're already
4068 * holding ctx->mutex which would be an inversion wrt. the
4069 * normal lock order.
4071 * However we can safely take this lock because its the child
4074 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4077 * We have to re-check the event->owner field, if it is cleared
4078 * we raced with perf_event_exit_task(), acquiring the mutex
4079 * ensured they're done, and we can proceed with freeing the
4083 list_del_init(&event->owner_entry);
4084 smp_store_release(&event->owner, NULL);
4086 mutex_unlock(&owner->perf_event_mutex);
4087 put_task_struct(owner);
4091 static void put_event(struct perf_event *event)
4093 if (!atomic_long_dec_and_test(&event->refcount))
4100 * Kill an event dead; while event:refcount will preserve the event
4101 * object, it will not preserve its functionality. Once the last 'user'
4102 * gives up the object, we'll destroy the thing.
4104 int perf_event_release_kernel(struct perf_event *event)
4106 struct perf_event_context *ctx = event->ctx;
4107 struct perf_event *child, *tmp;
4110 * If we got here through err_file: fput(event_file); we will not have
4111 * attached to a context yet.
4114 WARN_ON_ONCE(event->attach_state &
4115 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4119 if (!is_kernel_event(event))
4120 perf_remove_from_owner(event);
4122 ctx = perf_event_ctx_lock(event);
4123 WARN_ON_ONCE(ctx->parent_ctx);
4124 perf_remove_from_context(event, DETACH_GROUP);
4126 raw_spin_lock_irq(&ctx->lock);
4128 * Mark this even as STATE_DEAD, there is no external reference to it
4131 * Anybody acquiring event->child_mutex after the below loop _must_
4132 * also see this, most importantly inherit_event() which will avoid
4133 * placing more children on the list.
4135 * Thus this guarantees that we will in fact observe and kill _ALL_
4138 event->state = PERF_EVENT_STATE_DEAD;
4139 raw_spin_unlock_irq(&ctx->lock);
4141 perf_event_ctx_unlock(event, ctx);
4144 mutex_lock(&event->child_mutex);
4145 list_for_each_entry(child, &event->child_list, child_list) {
4148 * Cannot change, child events are not migrated, see the
4149 * comment with perf_event_ctx_lock_nested().
4151 ctx = lockless_dereference(child->ctx);
4153 * Since child_mutex nests inside ctx::mutex, we must jump
4154 * through hoops. We start by grabbing a reference on the ctx.
4156 * Since the event cannot get freed while we hold the
4157 * child_mutex, the context must also exist and have a !0
4163 * Now that we have a ctx ref, we can drop child_mutex, and
4164 * acquire ctx::mutex without fear of it going away. Then we
4165 * can re-acquire child_mutex.
4167 mutex_unlock(&event->child_mutex);
4168 mutex_lock(&ctx->mutex);
4169 mutex_lock(&event->child_mutex);
4172 * Now that we hold ctx::mutex and child_mutex, revalidate our
4173 * state, if child is still the first entry, it didn't get freed
4174 * and we can continue doing so.
4176 tmp = list_first_entry_or_null(&event->child_list,
4177 struct perf_event, child_list);
4179 perf_remove_from_context(child, DETACH_GROUP);
4180 list_del(&child->child_list);
4183 * This matches the refcount bump in inherit_event();
4184 * this can't be the last reference.
4189 mutex_unlock(&event->child_mutex);
4190 mutex_unlock(&ctx->mutex);
4194 mutex_unlock(&event->child_mutex);
4197 put_event(event); /* Must be the 'last' reference */
4200 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4203 * Called when the last reference to the file is gone.
4205 static int perf_release(struct inode *inode, struct file *file)
4207 perf_event_release_kernel(file->private_data);
4211 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4213 struct perf_event *child;
4219 mutex_lock(&event->child_mutex);
4221 (void)perf_event_read(event, false);
4222 total += perf_event_count(event);
4224 *enabled += event->total_time_enabled +
4225 atomic64_read(&event->child_total_time_enabled);
4226 *running += event->total_time_running +
4227 atomic64_read(&event->child_total_time_running);
4229 list_for_each_entry(child, &event->child_list, child_list) {
4230 (void)perf_event_read(child, false);
4231 total += perf_event_count(child);
4232 *enabled += child->total_time_enabled;
4233 *running += child->total_time_running;
4235 mutex_unlock(&event->child_mutex);
4239 EXPORT_SYMBOL_GPL(perf_event_read_value);
4241 static int __perf_read_group_add(struct perf_event *leader,
4242 u64 read_format, u64 *values)
4244 struct perf_event *sub;
4245 int n = 1; /* skip @nr */
4248 ret = perf_event_read(leader, true);
4253 * Since we co-schedule groups, {enabled,running} times of siblings
4254 * will be identical to those of the leader, so we only publish one
4257 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4258 values[n++] += leader->total_time_enabled +
4259 atomic64_read(&leader->child_total_time_enabled);
4262 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4263 values[n++] += leader->total_time_running +
4264 atomic64_read(&leader->child_total_time_running);
4268 * Write {count,id} tuples for every sibling.
4270 values[n++] += perf_event_count(leader);
4271 if (read_format & PERF_FORMAT_ID)
4272 values[n++] = primary_event_id(leader);
4274 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4275 values[n++] += perf_event_count(sub);
4276 if (read_format & PERF_FORMAT_ID)
4277 values[n++] = primary_event_id(sub);
4283 static int perf_read_group(struct perf_event *event,
4284 u64 read_format, char __user *buf)
4286 struct perf_event *leader = event->group_leader, *child;
4287 struct perf_event_context *ctx = leader->ctx;
4291 lockdep_assert_held(&ctx->mutex);
4293 values = kzalloc(event->read_size, GFP_KERNEL);
4297 values[0] = 1 + leader->nr_siblings;
4300 * By locking the child_mutex of the leader we effectively
4301 * lock the child list of all siblings.. XXX explain how.
4303 mutex_lock(&leader->child_mutex);
4305 ret = __perf_read_group_add(leader, read_format, values);
4309 list_for_each_entry(child, &leader->child_list, child_list) {
4310 ret = __perf_read_group_add(child, read_format, values);
4315 mutex_unlock(&leader->child_mutex);
4317 ret = event->read_size;
4318 if (copy_to_user(buf, values, event->read_size))
4323 mutex_unlock(&leader->child_mutex);
4329 static int perf_read_one(struct perf_event *event,
4330 u64 read_format, char __user *buf)
4332 u64 enabled, running;
4336 values[n++] = perf_event_read_value(event, &enabled, &running);
4337 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4338 values[n++] = enabled;
4339 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4340 values[n++] = running;
4341 if (read_format & PERF_FORMAT_ID)
4342 values[n++] = primary_event_id(event);
4344 if (copy_to_user(buf, values, n * sizeof(u64)))
4347 return n * sizeof(u64);
4350 static bool is_event_hup(struct perf_event *event)
4354 if (event->state > PERF_EVENT_STATE_EXIT)
4357 mutex_lock(&event->child_mutex);
4358 no_children = list_empty(&event->child_list);
4359 mutex_unlock(&event->child_mutex);
4364 * Read the performance event - simple non blocking version for now
4367 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4369 u64 read_format = event->attr.read_format;
4373 * Return end-of-file for a read on a event that is in
4374 * error state (i.e. because it was pinned but it couldn't be
4375 * scheduled on to the CPU at some point).
4377 if (event->state == PERF_EVENT_STATE_ERROR)
4380 if (count < event->read_size)
4383 WARN_ON_ONCE(event->ctx->parent_ctx);
4384 if (read_format & PERF_FORMAT_GROUP)
4385 ret = perf_read_group(event, read_format, buf);
4387 ret = perf_read_one(event, read_format, buf);
4393 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4395 struct perf_event *event = file->private_data;
4396 struct perf_event_context *ctx;
4399 ctx = perf_event_ctx_lock(event);
4400 ret = __perf_read(event, buf, count);
4401 perf_event_ctx_unlock(event, ctx);
4406 static unsigned int perf_poll(struct file *file, poll_table *wait)
4408 struct perf_event *event = file->private_data;
4409 struct ring_buffer *rb;
4410 unsigned int events = POLLHUP;
4412 poll_wait(file, &event->waitq, wait);
4414 if (is_event_hup(event))
4418 * Pin the event->rb by taking event->mmap_mutex; otherwise
4419 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4421 mutex_lock(&event->mmap_mutex);
4424 events = atomic_xchg(&rb->poll, 0);
4425 mutex_unlock(&event->mmap_mutex);
4429 static void _perf_event_reset(struct perf_event *event)
4431 (void)perf_event_read(event, false);
4432 local64_set(&event->count, 0);
4433 perf_event_update_userpage(event);
4437 * Holding the top-level event's child_mutex means that any
4438 * descendant process that has inherited this event will block
4439 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4440 * task existence requirements of perf_event_enable/disable.
4442 static void perf_event_for_each_child(struct perf_event *event,
4443 void (*func)(struct perf_event *))
4445 struct perf_event *child;
4447 WARN_ON_ONCE(event->ctx->parent_ctx);
4449 mutex_lock(&event->child_mutex);
4451 list_for_each_entry(child, &event->child_list, child_list)
4453 mutex_unlock(&event->child_mutex);
4456 static void perf_event_for_each(struct perf_event *event,
4457 void (*func)(struct perf_event *))
4459 struct perf_event_context *ctx = event->ctx;
4460 struct perf_event *sibling;
4462 lockdep_assert_held(&ctx->mutex);
4464 event = event->group_leader;
4466 perf_event_for_each_child(event, func);
4467 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4468 perf_event_for_each_child(sibling, func);
4471 static void __perf_event_period(struct perf_event *event,
4472 struct perf_cpu_context *cpuctx,
4473 struct perf_event_context *ctx,
4476 u64 value = *((u64 *)info);
4479 if (event->attr.freq) {
4480 event->attr.sample_freq = value;
4482 event->attr.sample_period = value;
4483 event->hw.sample_period = value;
4486 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4488 perf_pmu_disable(ctx->pmu);
4490 * We could be throttled; unthrottle now to avoid the tick
4491 * trying to unthrottle while we already re-started the event.
4493 if (event->hw.interrupts == MAX_INTERRUPTS) {
4494 event->hw.interrupts = 0;
4495 perf_log_throttle(event, 1);
4497 event->pmu->stop(event, PERF_EF_UPDATE);
4500 local64_set(&event->hw.period_left, 0);
4503 event->pmu->start(event, PERF_EF_RELOAD);
4504 perf_pmu_enable(ctx->pmu);
4508 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4512 if (!is_sampling_event(event))
4515 if (copy_from_user(&value, arg, sizeof(value)))
4521 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4524 event_function_call(event, __perf_event_period, &value);
4529 static const struct file_operations perf_fops;
4531 static inline int perf_fget_light(int fd, struct fd *p)
4533 struct fd f = fdget(fd);
4537 if (f.file->f_op != &perf_fops) {
4545 static int perf_event_set_output(struct perf_event *event,
4546 struct perf_event *output_event);
4547 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4548 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4550 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4552 void (*func)(struct perf_event *);
4556 case PERF_EVENT_IOC_ENABLE:
4557 func = _perf_event_enable;
4559 case PERF_EVENT_IOC_DISABLE:
4560 func = _perf_event_disable;
4562 case PERF_EVENT_IOC_RESET:
4563 func = _perf_event_reset;
4566 case PERF_EVENT_IOC_REFRESH:
4567 return _perf_event_refresh(event, arg);
4569 case PERF_EVENT_IOC_PERIOD:
4570 return perf_event_period(event, (u64 __user *)arg);
4572 case PERF_EVENT_IOC_ID:
4574 u64 id = primary_event_id(event);
4576 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4581 case PERF_EVENT_IOC_SET_OUTPUT:
4585 struct perf_event *output_event;
4587 ret = perf_fget_light(arg, &output);
4590 output_event = output.file->private_data;
4591 ret = perf_event_set_output(event, output_event);
4594 ret = perf_event_set_output(event, NULL);
4599 case PERF_EVENT_IOC_SET_FILTER:
4600 return perf_event_set_filter(event, (void __user *)arg);
4602 case PERF_EVENT_IOC_SET_BPF:
4603 return perf_event_set_bpf_prog(event, arg);
4605 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4606 struct ring_buffer *rb;
4609 rb = rcu_dereference(event->rb);
4610 if (!rb || !rb->nr_pages) {
4614 rb_toggle_paused(rb, !!arg);
4622 if (flags & PERF_IOC_FLAG_GROUP)
4623 perf_event_for_each(event, func);
4625 perf_event_for_each_child(event, func);
4630 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4632 struct perf_event *event = file->private_data;
4633 struct perf_event_context *ctx;
4636 ctx = perf_event_ctx_lock(event);
4637 ret = _perf_ioctl(event, cmd, arg);
4638 perf_event_ctx_unlock(event, ctx);
4643 #ifdef CONFIG_COMPAT
4644 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4647 switch (_IOC_NR(cmd)) {
4648 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4649 case _IOC_NR(PERF_EVENT_IOC_ID):
4650 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4651 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4652 cmd &= ~IOCSIZE_MASK;
4653 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4657 return perf_ioctl(file, cmd, arg);
4660 # define perf_compat_ioctl NULL
4663 int perf_event_task_enable(void)
4665 struct perf_event_context *ctx;
4666 struct perf_event *event;
4668 mutex_lock(¤t->perf_event_mutex);
4669 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4670 ctx = perf_event_ctx_lock(event);
4671 perf_event_for_each_child(event, _perf_event_enable);
4672 perf_event_ctx_unlock(event, ctx);
4674 mutex_unlock(¤t->perf_event_mutex);
4679 int perf_event_task_disable(void)
4681 struct perf_event_context *ctx;
4682 struct perf_event *event;
4684 mutex_lock(¤t->perf_event_mutex);
4685 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4686 ctx = perf_event_ctx_lock(event);
4687 perf_event_for_each_child(event, _perf_event_disable);
4688 perf_event_ctx_unlock(event, ctx);
4690 mutex_unlock(¤t->perf_event_mutex);
4695 static int perf_event_index(struct perf_event *event)
4697 if (event->hw.state & PERF_HES_STOPPED)
4700 if (event->state != PERF_EVENT_STATE_ACTIVE)
4703 return event->pmu->event_idx(event);
4706 static void calc_timer_values(struct perf_event *event,
4713 *now = perf_clock();
4714 ctx_time = event->shadow_ctx_time + *now;
4715 *enabled = ctx_time - event->tstamp_enabled;
4716 *running = ctx_time - event->tstamp_running;
4719 static void perf_event_init_userpage(struct perf_event *event)
4721 struct perf_event_mmap_page *userpg;
4722 struct ring_buffer *rb;
4725 rb = rcu_dereference(event->rb);
4729 userpg = rb->user_page;
4731 /* Allow new userspace to detect that bit 0 is deprecated */
4732 userpg->cap_bit0_is_deprecated = 1;
4733 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4734 userpg->data_offset = PAGE_SIZE;
4735 userpg->data_size = perf_data_size(rb);
4741 void __weak arch_perf_update_userpage(
4742 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4747 * Callers need to ensure there can be no nesting of this function, otherwise
4748 * the seqlock logic goes bad. We can not serialize this because the arch
4749 * code calls this from NMI context.
4751 void perf_event_update_userpage(struct perf_event *event)
4753 struct perf_event_mmap_page *userpg;
4754 struct ring_buffer *rb;
4755 u64 enabled, running, now;
4758 rb = rcu_dereference(event->rb);
4763 * compute total_time_enabled, total_time_running
4764 * based on snapshot values taken when the event
4765 * was last scheduled in.
4767 * we cannot simply called update_context_time()
4768 * because of locking issue as we can be called in
4771 calc_timer_values(event, &now, &enabled, &running);
4773 userpg = rb->user_page;
4775 * Disable preemption so as to not let the corresponding user-space
4776 * spin too long if we get preempted.
4781 userpg->index = perf_event_index(event);
4782 userpg->offset = perf_event_count(event);
4784 userpg->offset -= local64_read(&event->hw.prev_count);
4786 userpg->time_enabled = enabled +
4787 atomic64_read(&event->child_total_time_enabled);
4789 userpg->time_running = running +
4790 atomic64_read(&event->child_total_time_running);
4792 arch_perf_update_userpage(event, userpg, now);
4801 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4803 struct perf_event *event = vma->vm_file->private_data;
4804 struct ring_buffer *rb;
4805 int ret = VM_FAULT_SIGBUS;
4807 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4808 if (vmf->pgoff == 0)
4814 rb = rcu_dereference(event->rb);
4818 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4821 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4825 get_page(vmf->page);
4826 vmf->page->mapping = vma->vm_file->f_mapping;
4827 vmf->page->index = vmf->pgoff;
4836 static void ring_buffer_attach(struct perf_event *event,
4837 struct ring_buffer *rb)
4839 struct ring_buffer *old_rb = NULL;
4840 unsigned long flags;
4844 * Should be impossible, we set this when removing
4845 * event->rb_entry and wait/clear when adding event->rb_entry.
4847 WARN_ON_ONCE(event->rcu_pending);
4850 spin_lock_irqsave(&old_rb->event_lock, flags);
4851 list_del_rcu(&event->rb_entry);
4852 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4854 event->rcu_batches = get_state_synchronize_rcu();
4855 event->rcu_pending = 1;
4859 if (event->rcu_pending) {
4860 cond_synchronize_rcu(event->rcu_batches);
4861 event->rcu_pending = 0;
4864 spin_lock_irqsave(&rb->event_lock, flags);
4865 list_add_rcu(&event->rb_entry, &rb->event_list);
4866 spin_unlock_irqrestore(&rb->event_lock, flags);
4869 rcu_assign_pointer(event->rb, rb);
4872 ring_buffer_put(old_rb);
4874 * Since we detached before setting the new rb, so that we
4875 * could attach the new rb, we could have missed a wakeup.
4878 wake_up_all(&event->waitq);
4882 static void ring_buffer_wakeup(struct perf_event *event)
4884 struct ring_buffer *rb;
4887 rb = rcu_dereference(event->rb);
4889 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4890 wake_up_all(&event->waitq);
4895 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4897 struct ring_buffer *rb;
4900 rb = rcu_dereference(event->rb);
4902 if (!atomic_inc_not_zero(&rb->refcount))
4910 void ring_buffer_put(struct ring_buffer *rb)
4912 if (!atomic_dec_and_test(&rb->refcount))
4915 WARN_ON_ONCE(!list_empty(&rb->event_list));
4917 call_rcu(&rb->rcu_head, rb_free_rcu);
4920 static void perf_mmap_open(struct vm_area_struct *vma)
4922 struct perf_event *event = vma->vm_file->private_data;
4924 atomic_inc(&event->mmap_count);
4925 atomic_inc(&event->rb->mmap_count);
4928 atomic_inc(&event->rb->aux_mmap_count);
4930 if (event->pmu->event_mapped)
4931 event->pmu->event_mapped(event);
4934 static void perf_pmu_output_stop(struct perf_event *event);
4937 * A buffer can be mmap()ed multiple times; either directly through the same
4938 * event, or through other events by use of perf_event_set_output().
4940 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4941 * the buffer here, where we still have a VM context. This means we need
4942 * to detach all events redirecting to us.
4944 static void perf_mmap_close(struct vm_area_struct *vma)
4946 struct perf_event *event = vma->vm_file->private_data;
4948 struct ring_buffer *rb = ring_buffer_get(event);
4949 struct user_struct *mmap_user = rb->mmap_user;
4950 int mmap_locked = rb->mmap_locked;
4951 unsigned long size = perf_data_size(rb);
4953 if (event->pmu->event_unmapped)
4954 event->pmu->event_unmapped(event);
4957 * rb->aux_mmap_count will always drop before rb->mmap_count and
4958 * event->mmap_count, so it is ok to use event->mmap_mutex to
4959 * serialize with perf_mmap here.
4961 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4962 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4964 * Stop all AUX events that are writing to this buffer,
4965 * so that we can free its AUX pages and corresponding PMU
4966 * data. Note that after rb::aux_mmap_count dropped to zero,
4967 * they won't start any more (see perf_aux_output_begin()).
4969 perf_pmu_output_stop(event);
4971 /* now it's safe to free the pages */
4972 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4973 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4975 /* this has to be the last one */
4977 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4979 mutex_unlock(&event->mmap_mutex);
4982 atomic_dec(&rb->mmap_count);
4984 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4987 ring_buffer_attach(event, NULL);
4988 mutex_unlock(&event->mmap_mutex);
4990 /* If there's still other mmap()s of this buffer, we're done. */
4991 if (atomic_read(&rb->mmap_count))
4995 * No other mmap()s, detach from all other events that might redirect
4996 * into the now unreachable buffer. Somewhat complicated by the
4997 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5001 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5002 if (!atomic_long_inc_not_zero(&event->refcount)) {
5004 * This event is en-route to free_event() which will
5005 * detach it and remove it from the list.
5011 mutex_lock(&event->mmap_mutex);
5013 * Check we didn't race with perf_event_set_output() which can
5014 * swizzle the rb from under us while we were waiting to
5015 * acquire mmap_mutex.
5017 * If we find a different rb; ignore this event, a next
5018 * iteration will no longer find it on the list. We have to
5019 * still restart the iteration to make sure we're not now
5020 * iterating the wrong list.
5022 if (event->rb == rb)
5023 ring_buffer_attach(event, NULL);
5025 mutex_unlock(&event->mmap_mutex);
5029 * Restart the iteration; either we're on the wrong list or
5030 * destroyed its integrity by doing a deletion.
5037 * It could be there's still a few 0-ref events on the list; they'll
5038 * get cleaned up by free_event() -- they'll also still have their
5039 * ref on the rb and will free it whenever they are done with it.
5041 * Aside from that, this buffer is 'fully' detached and unmapped,
5042 * undo the VM accounting.
5045 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5046 vma->vm_mm->pinned_vm -= mmap_locked;
5047 free_uid(mmap_user);
5050 ring_buffer_put(rb); /* could be last */
5053 static const struct vm_operations_struct perf_mmap_vmops = {
5054 .open = perf_mmap_open,
5055 .close = perf_mmap_close, /* non mergable */
5056 .fault = perf_mmap_fault,
5057 .page_mkwrite = perf_mmap_fault,
5060 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5062 struct perf_event *event = file->private_data;
5063 unsigned long user_locked, user_lock_limit;
5064 struct user_struct *user = current_user();
5065 unsigned long locked, lock_limit;
5066 struct ring_buffer *rb = NULL;
5067 unsigned long vma_size;
5068 unsigned long nr_pages;
5069 long user_extra = 0, extra = 0;
5070 int ret = 0, flags = 0;
5073 * Don't allow mmap() of inherited per-task counters. This would
5074 * create a performance issue due to all children writing to the
5077 if (event->cpu == -1 && event->attr.inherit)
5080 if (!(vma->vm_flags & VM_SHARED))
5083 vma_size = vma->vm_end - vma->vm_start;
5085 if (vma->vm_pgoff == 0) {
5086 nr_pages = (vma_size / PAGE_SIZE) - 1;
5089 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5090 * mapped, all subsequent mappings should have the same size
5091 * and offset. Must be above the normal perf buffer.
5093 u64 aux_offset, aux_size;
5098 nr_pages = vma_size / PAGE_SIZE;
5100 mutex_lock(&event->mmap_mutex);
5107 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5108 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5110 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5113 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5116 /* already mapped with a different offset */
5117 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5120 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5123 /* already mapped with a different size */
5124 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5127 if (!is_power_of_2(nr_pages))
5130 if (!atomic_inc_not_zero(&rb->mmap_count))
5133 if (rb_has_aux(rb)) {
5134 atomic_inc(&rb->aux_mmap_count);
5139 atomic_set(&rb->aux_mmap_count, 1);
5140 user_extra = nr_pages;
5146 * If we have rb pages ensure they're a power-of-two number, so we
5147 * can do bitmasks instead of modulo.
5149 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5152 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5155 WARN_ON_ONCE(event->ctx->parent_ctx);
5157 mutex_lock(&event->mmap_mutex);
5159 if (event->rb->nr_pages != nr_pages) {
5164 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5166 * Raced against perf_mmap_close() through
5167 * perf_event_set_output(). Try again, hope for better
5170 mutex_unlock(&event->mmap_mutex);
5177 user_extra = nr_pages + 1;
5180 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5183 * Increase the limit linearly with more CPUs:
5185 user_lock_limit *= num_online_cpus();
5187 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5189 if (user_locked > user_lock_limit)
5190 extra = user_locked - user_lock_limit;
5192 lock_limit = rlimit(RLIMIT_MEMLOCK);
5193 lock_limit >>= PAGE_SHIFT;
5194 locked = vma->vm_mm->pinned_vm + extra;
5196 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5197 !capable(CAP_IPC_LOCK)) {
5202 WARN_ON(!rb && event->rb);
5204 if (vma->vm_flags & VM_WRITE)
5205 flags |= RING_BUFFER_WRITABLE;
5208 rb = rb_alloc(nr_pages,
5209 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5217 atomic_set(&rb->mmap_count, 1);
5218 rb->mmap_user = get_current_user();
5219 rb->mmap_locked = extra;
5221 ring_buffer_attach(event, rb);
5223 perf_event_init_userpage(event);
5224 perf_event_update_userpage(event);
5226 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5227 event->attr.aux_watermark, flags);
5229 rb->aux_mmap_locked = extra;
5234 atomic_long_add(user_extra, &user->locked_vm);
5235 vma->vm_mm->pinned_vm += extra;
5237 atomic_inc(&event->mmap_count);
5239 atomic_dec(&rb->mmap_count);
5242 mutex_unlock(&event->mmap_mutex);
5245 * Since pinned accounting is per vm we cannot allow fork() to copy our
5248 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5249 vma->vm_ops = &perf_mmap_vmops;
5251 if (event->pmu->event_mapped)
5252 event->pmu->event_mapped(event);
5257 static int perf_fasync(int fd, struct file *filp, int on)
5259 struct inode *inode = file_inode(filp);
5260 struct perf_event *event = filp->private_data;
5264 retval = fasync_helper(fd, filp, on, &event->fasync);
5265 inode_unlock(inode);
5273 static const struct file_operations perf_fops = {
5274 .llseek = no_llseek,
5275 .release = perf_release,
5278 .unlocked_ioctl = perf_ioctl,
5279 .compat_ioctl = perf_compat_ioctl,
5281 .fasync = perf_fasync,
5287 * If there's data, ensure we set the poll() state and publish everything
5288 * to user-space before waking everybody up.
5291 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5293 /* only the parent has fasync state */
5295 event = event->parent;
5296 return &event->fasync;
5299 void perf_event_wakeup(struct perf_event *event)
5301 ring_buffer_wakeup(event);
5303 if (event->pending_kill) {
5304 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5305 event->pending_kill = 0;
5309 static void perf_pending_event(struct irq_work *entry)
5311 struct perf_event *event = container_of(entry,
5312 struct perf_event, pending);
5315 rctx = perf_swevent_get_recursion_context();
5317 * If we 'fail' here, that's OK, it means recursion is already disabled
5318 * and we won't recurse 'further'.
5321 if (event->pending_disable) {
5322 event->pending_disable = 0;
5323 perf_event_disable_local(event);
5326 if (event->pending_wakeup) {
5327 event->pending_wakeup = 0;
5328 perf_event_wakeup(event);
5332 perf_swevent_put_recursion_context(rctx);
5336 * We assume there is only KVM supporting the callbacks.
5337 * Later on, we might change it to a list if there is
5338 * another virtualization implementation supporting the callbacks.
5340 struct perf_guest_info_callbacks *perf_guest_cbs;
5342 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5344 perf_guest_cbs = cbs;
5347 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5349 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5351 perf_guest_cbs = NULL;
5354 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5357 perf_output_sample_regs(struct perf_output_handle *handle,
5358 struct pt_regs *regs, u64 mask)
5361 DECLARE_BITMAP(_mask, 64);
5363 bitmap_from_u64(_mask, mask);
5364 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5367 val = perf_reg_value(regs, bit);
5368 perf_output_put(handle, val);
5372 static void perf_sample_regs_user(struct perf_regs *regs_user,
5373 struct pt_regs *regs,
5374 struct pt_regs *regs_user_copy)
5376 if (user_mode(regs)) {
5377 regs_user->abi = perf_reg_abi(current);
5378 regs_user->regs = regs;
5379 } else if (current->mm) {
5380 perf_get_regs_user(regs_user, regs, regs_user_copy);
5382 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5383 regs_user->regs = NULL;
5387 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5388 struct pt_regs *regs)
5390 regs_intr->regs = regs;
5391 regs_intr->abi = perf_reg_abi(current);
5396 * Get remaining task size from user stack pointer.
5398 * It'd be better to take stack vma map and limit this more
5399 * precisly, but there's no way to get it safely under interrupt,
5400 * so using TASK_SIZE as limit.
5402 static u64 perf_ustack_task_size(struct pt_regs *regs)
5404 unsigned long addr = perf_user_stack_pointer(regs);
5406 if (!addr || addr >= TASK_SIZE)
5409 return TASK_SIZE - addr;
5413 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5414 struct pt_regs *regs)
5418 /* No regs, no stack pointer, no dump. */
5423 * Check if we fit in with the requested stack size into the:
5425 * If we don't, we limit the size to the TASK_SIZE.
5427 * - remaining sample size
5428 * If we don't, we customize the stack size to
5429 * fit in to the remaining sample size.
5432 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5433 stack_size = min(stack_size, (u16) task_size);
5435 /* Current header size plus static size and dynamic size. */
5436 header_size += 2 * sizeof(u64);
5438 /* Do we fit in with the current stack dump size? */
5439 if ((u16) (header_size + stack_size) < header_size) {
5441 * If we overflow the maximum size for the sample,
5442 * we customize the stack dump size to fit in.
5444 stack_size = USHRT_MAX - header_size - sizeof(u64);
5445 stack_size = round_up(stack_size, sizeof(u64));
5452 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5453 struct pt_regs *regs)
5455 /* Case of a kernel thread, nothing to dump */
5458 perf_output_put(handle, size);
5467 * - the size requested by user or the best one we can fit
5468 * in to the sample max size
5470 * - user stack dump data
5472 * - the actual dumped size
5476 perf_output_put(handle, dump_size);
5479 sp = perf_user_stack_pointer(regs);
5480 rem = __output_copy_user(handle, (void *) sp, dump_size);
5481 dyn_size = dump_size - rem;
5483 perf_output_skip(handle, rem);
5486 perf_output_put(handle, dyn_size);
5490 static void __perf_event_header__init_id(struct perf_event_header *header,
5491 struct perf_sample_data *data,
5492 struct perf_event *event)
5494 u64 sample_type = event->attr.sample_type;
5496 data->type = sample_type;
5497 header->size += event->id_header_size;
5499 if (sample_type & PERF_SAMPLE_TID) {
5500 /* namespace issues */
5501 data->tid_entry.pid = perf_event_pid(event, current);
5502 data->tid_entry.tid = perf_event_tid(event, current);
5505 if (sample_type & PERF_SAMPLE_TIME)
5506 data->time = perf_event_clock(event);
5508 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5509 data->id = primary_event_id(event);
5511 if (sample_type & PERF_SAMPLE_STREAM_ID)
5512 data->stream_id = event->id;
5514 if (sample_type & PERF_SAMPLE_CPU) {
5515 data->cpu_entry.cpu = raw_smp_processor_id();
5516 data->cpu_entry.reserved = 0;
5520 void perf_event_header__init_id(struct perf_event_header *header,
5521 struct perf_sample_data *data,
5522 struct perf_event *event)
5524 if (event->attr.sample_id_all)
5525 __perf_event_header__init_id(header, data, event);
5528 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5529 struct perf_sample_data *data)
5531 u64 sample_type = data->type;
5533 if (sample_type & PERF_SAMPLE_TID)
5534 perf_output_put(handle, data->tid_entry);
5536 if (sample_type & PERF_SAMPLE_TIME)
5537 perf_output_put(handle, data->time);
5539 if (sample_type & PERF_SAMPLE_ID)
5540 perf_output_put(handle, data->id);
5542 if (sample_type & PERF_SAMPLE_STREAM_ID)
5543 perf_output_put(handle, data->stream_id);
5545 if (sample_type & PERF_SAMPLE_CPU)
5546 perf_output_put(handle, data->cpu_entry);
5548 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5549 perf_output_put(handle, data->id);
5552 void perf_event__output_id_sample(struct perf_event *event,
5553 struct perf_output_handle *handle,
5554 struct perf_sample_data *sample)
5556 if (event->attr.sample_id_all)
5557 __perf_event__output_id_sample(handle, sample);
5560 static void perf_output_read_one(struct perf_output_handle *handle,
5561 struct perf_event *event,
5562 u64 enabled, u64 running)
5564 u64 read_format = event->attr.read_format;
5568 values[n++] = perf_event_count(event);
5569 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5570 values[n++] = enabled +
5571 atomic64_read(&event->child_total_time_enabled);
5573 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5574 values[n++] = running +
5575 atomic64_read(&event->child_total_time_running);
5577 if (read_format & PERF_FORMAT_ID)
5578 values[n++] = primary_event_id(event);
5580 __output_copy(handle, values, n * sizeof(u64));
5584 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5586 static void perf_output_read_group(struct perf_output_handle *handle,
5587 struct perf_event *event,
5588 u64 enabled, u64 running)
5590 struct perf_event *leader = event->group_leader, *sub;
5591 u64 read_format = event->attr.read_format;
5595 values[n++] = 1 + leader->nr_siblings;
5597 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5598 values[n++] = enabled;
5600 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5601 values[n++] = running;
5603 if (leader != event)
5604 leader->pmu->read(leader);
5606 values[n++] = perf_event_count(leader);
5607 if (read_format & PERF_FORMAT_ID)
5608 values[n++] = primary_event_id(leader);
5610 __output_copy(handle, values, n * sizeof(u64));
5612 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5615 if ((sub != event) &&
5616 (sub->state == PERF_EVENT_STATE_ACTIVE))
5617 sub->pmu->read(sub);
5619 values[n++] = perf_event_count(sub);
5620 if (read_format & PERF_FORMAT_ID)
5621 values[n++] = primary_event_id(sub);
5623 __output_copy(handle, values, n * sizeof(u64));
5627 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5628 PERF_FORMAT_TOTAL_TIME_RUNNING)
5630 static void perf_output_read(struct perf_output_handle *handle,
5631 struct perf_event *event)
5633 u64 enabled = 0, running = 0, now;
5634 u64 read_format = event->attr.read_format;
5637 * compute total_time_enabled, total_time_running
5638 * based on snapshot values taken when the event
5639 * was last scheduled in.
5641 * we cannot simply called update_context_time()
5642 * because of locking issue as we are called in
5645 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5646 calc_timer_values(event, &now, &enabled, &running);
5648 if (event->attr.read_format & PERF_FORMAT_GROUP)
5649 perf_output_read_group(handle, event, enabled, running);
5651 perf_output_read_one(handle, event, enabled, running);
5654 void perf_output_sample(struct perf_output_handle *handle,
5655 struct perf_event_header *header,
5656 struct perf_sample_data *data,
5657 struct perf_event *event)
5659 u64 sample_type = data->type;
5661 perf_output_put(handle, *header);
5663 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5664 perf_output_put(handle, data->id);
5666 if (sample_type & PERF_SAMPLE_IP)
5667 perf_output_put(handle, data->ip);
5669 if (sample_type & PERF_SAMPLE_TID)
5670 perf_output_put(handle, data->tid_entry);
5672 if (sample_type & PERF_SAMPLE_TIME)
5673 perf_output_put(handle, data->time);
5675 if (sample_type & PERF_SAMPLE_ADDR)
5676 perf_output_put(handle, data->addr);
5678 if (sample_type & PERF_SAMPLE_ID)
5679 perf_output_put(handle, data->id);
5681 if (sample_type & PERF_SAMPLE_STREAM_ID)
5682 perf_output_put(handle, data->stream_id);
5684 if (sample_type & PERF_SAMPLE_CPU)
5685 perf_output_put(handle, data->cpu_entry);
5687 if (sample_type & PERF_SAMPLE_PERIOD)
5688 perf_output_put(handle, data->period);
5690 if (sample_type & PERF_SAMPLE_READ)
5691 perf_output_read(handle, event);
5693 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5694 if (data->callchain) {
5697 if (data->callchain)
5698 size += data->callchain->nr;
5700 size *= sizeof(u64);
5702 __output_copy(handle, data->callchain, size);
5705 perf_output_put(handle, nr);
5709 if (sample_type & PERF_SAMPLE_RAW) {
5710 struct perf_raw_record *raw = data->raw;
5713 struct perf_raw_frag *frag = &raw->frag;
5715 perf_output_put(handle, raw->size);
5718 __output_custom(handle, frag->copy,
5719 frag->data, frag->size);
5721 __output_copy(handle, frag->data,
5724 if (perf_raw_frag_last(frag))
5729 __output_skip(handle, NULL, frag->pad);
5735 .size = sizeof(u32),
5738 perf_output_put(handle, raw);
5742 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5743 if (data->br_stack) {
5746 size = data->br_stack->nr
5747 * sizeof(struct perf_branch_entry);
5749 perf_output_put(handle, data->br_stack->nr);
5750 perf_output_copy(handle, data->br_stack->entries, size);
5753 * we always store at least the value of nr
5756 perf_output_put(handle, nr);
5760 if (sample_type & PERF_SAMPLE_REGS_USER) {
5761 u64 abi = data->regs_user.abi;
5764 * If there are no regs to dump, notice it through
5765 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5767 perf_output_put(handle, abi);
5770 u64 mask = event->attr.sample_regs_user;
5771 perf_output_sample_regs(handle,
5772 data->regs_user.regs,
5777 if (sample_type & PERF_SAMPLE_STACK_USER) {
5778 perf_output_sample_ustack(handle,
5779 data->stack_user_size,
5780 data->regs_user.regs);
5783 if (sample_type & PERF_SAMPLE_WEIGHT)
5784 perf_output_put(handle, data->weight);
5786 if (sample_type & PERF_SAMPLE_DATA_SRC)
5787 perf_output_put(handle, data->data_src.val);
5789 if (sample_type & PERF_SAMPLE_TRANSACTION)
5790 perf_output_put(handle, data->txn);
5792 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5793 u64 abi = data->regs_intr.abi;
5795 * If there are no regs to dump, notice it through
5796 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5798 perf_output_put(handle, abi);
5801 u64 mask = event->attr.sample_regs_intr;
5803 perf_output_sample_regs(handle,
5804 data->regs_intr.regs,
5809 if (!event->attr.watermark) {
5810 int wakeup_events = event->attr.wakeup_events;
5812 if (wakeup_events) {
5813 struct ring_buffer *rb = handle->rb;
5814 int events = local_inc_return(&rb->events);
5816 if (events >= wakeup_events) {
5817 local_sub(wakeup_events, &rb->events);
5818 local_inc(&rb->wakeup);
5824 void perf_prepare_sample(struct perf_event_header *header,
5825 struct perf_sample_data *data,
5826 struct perf_event *event,
5827 struct pt_regs *regs)
5829 u64 sample_type = event->attr.sample_type;
5831 header->type = PERF_RECORD_SAMPLE;
5832 header->size = sizeof(*header) + event->header_size;
5835 header->misc |= perf_misc_flags(regs);
5837 __perf_event_header__init_id(header, data, event);
5839 if (sample_type & PERF_SAMPLE_IP)
5840 data->ip = perf_instruction_pointer(regs);
5842 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5845 data->callchain = perf_callchain(event, regs);
5847 if (data->callchain)
5848 size += data->callchain->nr;
5850 header->size += size * sizeof(u64);
5853 if (sample_type & PERF_SAMPLE_RAW) {
5854 struct perf_raw_record *raw = data->raw;
5858 struct perf_raw_frag *frag = &raw->frag;
5863 if (perf_raw_frag_last(frag))
5868 size = round_up(sum + sizeof(u32), sizeof(u64));
5869 raw->size = size - sizeof(u32);
5870 frag->pad = raw->size - sum;
5875 header->size += size;
5878 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5879 int size = sizeof(u64); /* nr */
5880 if (data->br_stack) {
5881 size += data->br_stack->nr
5882 * sizeof(struct perf_branch_entry);
5884 header->size += size;
5887 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5888 perf_sample_regs_user(&data->regs_user, regs,
5889 &data->regs_user_copy);
5891 if (sample_type & PERF_SAMPLE_REGS_USER) {
5892 /* regs dump ABI info */
5893 int size = sizeof(u64);
5895 if (data->regs_user.regs) {
5896 u64 mask = event->attr.sample_regs_user;
5897 size += hweight64(mask) * sizeof(u64);
5900 header->size += size;
5903 if (sample_type & PERF_SAMPLE_STACK_USER) {
5905 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5906 * processed as the last one or have additional check added
5907 * in case new sample type is added, because we could eat
5908 * up the rest of the sample size.
5910 u16 stack_size = event->attr.sample_stack_user;
5911 u16 size = sizeof(u64);
5913 stack_size = perf_sample_ustack_size(stack_size, header->size,
5914 data->regs_user.regs);
5917 * If there is something to dump, add space for the dump
5918 * itself and for the field that tells the dynamic size,
5919 * which is how many have been actually dumped.
5922 size += sizeof(u64) + stack_size;
5924 data->stack_user_size = stack_size;
5925 header->size += size;
5928 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5929 /* regs dump ABI info */
5930 int size = sizeof(u64);
5932 perf_sample_regs_intr(&data->regs_intr, regs);
5934 if (data->regs_intr.regs) {
5935 u64 mask = event->attr.sample_regs_intr;
5937 size += hweight64(mask) * sizeof(u64);
5940 header->size += size;
5944 static void __always_inline
5945 __perf_event_output(struct perf_event *event,
5946 struct perf_sample_data *data,
5947 struct pt_regs *regs,
5948 int (*output_begin)(struct perf_output_handle *,
5949 struct perf_event *,
5952 struct perf_output_handle handle;
5953 struct perf_event_header header;
5955 /* protect the callchain buffers */
5958 perf_prepare_sample(&header, data, event, regs);
5960 if (output_begin(&handle, event, header.size))
5963 perf_output_sample(&handle, &header, data, event);
5965 perf_output_end(&handle);
5972 perf_event_output_forward(struct perf_event *event,
5973 struct perf_sample_data *data,
5974 struct pt_regs *regs)
5976 __perf_event_output(event, data, regs, perf_output_begin_forward);
5980 perf_event_output_backward(struct perf_event *event,
5981 struct perf_sample_data *data,
5982 struct pt_regs *regs)
5984 __perf_event_output(event, data, regs, perf_output_begin_backward);
5988 perf_event_output(struct perf_event *event,
5989 struct perf_sample_data *data,
5990 struct pt_regs *regs)
5992 __perf_event_output(event, data, regs, perf_output_begin);
5999 struct perf_read_event {
6000 struct perf_event_header header;
6007 perf_event_read_event(struct perf_event *event,
6008 struct task_struct *task)
6010 struct perf_output_handle handle;
6011 struct perf_sample_data sample;
6012 struct perf_read_event read_event = {
6014 .type = PERF_RECORD_READ,
6016 .size = sizeof(read_event) + event->read_size,
6018 .pid = perf_event_pid(event, task),
6019 .tid = perf_event_tid(event, task),
6023 perf_event_header__init_id(&read_event.header, &sample, event);
6024 ret = perf_output_begin(&handle, event, read_event.header.size);
6028 perf_output_put(&handle, read_event);
6029 perf_output_read(&handle, event);
6030 perf_event__output_id_sample(event, &handle, &sample);
6032 perf_output_end(&handle);
6035 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6038 perf_iterate_ctx(struct perf_event_context *ctx,
6039 perf_iterate_f output,
6040 void *data, bool all)
6042 struct perf_event *event;
6044 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6046 if (event->state < PERF_EVENT_STATE_INACTIVE)
6048 if (!event_filter_match(event))
6052 output(event, data);
6056 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6058 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6059 struct perf_event *event;
6061 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6063 * Skip events that are not fully formed yet; ensure that
6064 * if we observe event->ctx, both event and ctx will be
6065 * complete enough. See perf_install_in_context().
6067 if (!smp_load_acquire(&event->ctx))
6070 if (event->state < PERF_EVENT_STATE_INACTIVE)
6072 if (!event_filter_match(event))
6074 output(event, data);
6079 * Iterate all events that need to receive side-band events.
6081 * For new callers; ensure that account_pmu_sb_event() includes
6082 * your event, otherwise it might not get delivered.
6085 perf_iterate_sb(perf_iterate_f output, void *data,
6086 struct perf_event_context *task_ctx)
6088 struct perf_event_context *ctx;
6095 * If we have task_ctx != NULL we only notify the task context itself.
6096 * The task_ctx is set only for EXIT events before releasing task
6100 perf_iterate_ctx(task_ctx, output, data, false);
6104 perf_iterate_sb_cpu(output, data);
6106 for_each_task_context_nr(ctxn) {
6107 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6109 perf_iterate_ctx(ctx, output, data, false);
6117 * Clear all file-based filters at exec, they'll have to be
6118 * re-instated when/if these objects are mmapped again.
6120 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6122 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6123 struct perf_addr_filter *filter;
6124 unsigned int restart = 0, count = 0;
6125 unsigned long flags;
6127 if (!has_addr_filter(event))
6130 raw_spin_lock_irqsave(&ifh->lock, flags);
6131 list_for_each_entry(filter, &ifh->list, entry) {
6132 if (filter->inode) {
6133 event->addr_filters_offs[count] = 0;
6141 event->addr_filters_gen++;
6142 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6145 perf_event_restart(event);
6148 void perf_event_exec(void)
6150 struct perf_event_context *ctx;
6154 for_each_task_context_nr(ctxn) {
6155 ctx = current->perf_event_ctxp[ctxn];
6159 perf_event_enable_on_exec(ctxn);
6161 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6167 struct remote_output {
6168 struct ring_buffer *rb;
6172 static void __perf_event_output_stop(struct perf_event *event, void *data)
6174 struct perf_event *parent = event->parent;
6175 struct remote_output *ro = data;
6176 struct ring_buffer *rb = ro->rb;
6177 struct stop_event_data sd = {
6181 if (!has_aux(event))
6188 * In case of inheritance, it will be the parent that links to the
6189 * ring-buffer, but it will be the child that's actually using it:
6191 if (rcu_dereference(parent->rb) == rb)
6192 ro->err = __perf_event_stop(&sd);
6195 static int __perf_pmu_output_stop(void *info)
6197 struct perf_event *event = info;
6198 struct pmu *pmu = event->pmu;
6199 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
6200 struct remote_output ro = {
6205 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6206 if (cpuctx->task_ctx)
6207 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6214 static void perf_pmu_output_stop(struct perf_event *event)
6216 struct perf_event *iter;
6221 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6223 * For per-CPU events, we need to make sure that neither they
6224 * nor their children are running; for cpu==-1 events it's
6225 * sufficient to stop the event itself if it's active, since
6226 * it can't have children.
6230 cpu = READ_ONCE(iter->oncpu);
6235 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6236 if (err == -EAGAIN) {
6245 * task tracking -- fork/exit
6247 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6250 struct perf_task_event {
6251 struct task_struct *task;
6252 struct perf_event_context *task_ctx;
6255 struct perf_event_header header;
6265 static int perf_event_task_match(struct perf_event *event)
6267 return event->attr.comm || event->attr.mmap ||
6268 event->attr.mmap2 || event->attr.mmap_data ||
6272 static void perf_event_task_output(struct perf_event *event,
6275 struct perf_task_event *task_event = data;
6276 struct perf_output_handle handle;
6277 struct perf_sample_data sample;
6278 struct task_struct *task = task_event->task;
6279 int ret, size = task_event->event_id.header.size;
6281 if (!perf_event_task_match(event))
6284 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6286 ret = perf_output_begin(&handle, event,
6287 task_event->event_id.header.size);
6291 task_event->event_id.pid = perf_event_pid(event, task);
6292 task_event->event_id.ppid = perf_event_pid(event, current);
6294 task_event->event_id.tid = perf_event_tid(event, task);
6295 task_event->event_id.ptid = perf_event_tid(event, current);
6297 task_event->event_id.time = perf_event_clock(event);
6299 perf_output_put(&handle, task_event->event_id);
6301 perf_event__output_id_sample(event, &handle, &sample);
6303 perf_output_end(&handle);
6305 task_event->event_id.header.size = size;
6308 static void perf_event_task(struct task_struct *task,
6309 struct perf_event_context *task_ctx,
6312 struct perf_task_event task_event;
6314 if (!atomic_read(&nr_comm_events) &&
6315 !atomic_read(&nr_mmap_events) &&
6316 !atomic_read(&nr_task_events))
6319 task_event = (struct perf_task_event){
6321 .task_ctx = task_ctx,
6324 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6326 .size = sizeof(task_event.event_id),
6336 perf_iterate_sb(perf_event_task_output,
6341 void perf_event_fork(struct task_struct *task)
6343 perf_event_task(task, NULL, 1);
6350 struct perf_comm_event {
6351 struct task_struct *task;
6356 struct perf_event_header header;
6363 static int perf_event_comm_match(struct perf_event *event)
6365 return event->attr.comm;
6368 static void perf_event_comm_output(struct perf_event *event,
6371 struct perf_comm_event *comm_event = data;
6372 struct perf_output_handle handle;
6373 struct perf_sample_data sample;
6374 int size = comm_event->event_id.header.size;
6377 if (!perf_event_comm_match(event))
6380 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6381 ret = perf_output_begin(&handle, event,
6382 comm_event->event_id.header.size);
6387 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6388 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6390 perf_output_put(&handle, comm_event->event_id);
6391 __output_copy(&handle, comm_event->comm,
6392 comm_event->comm_size);
6394 perf_event__output_id_sample(event, &handle, &sample);
6396 perf_output_end(&handle);
6398 comm_event->event_id.header.size = size;
6401 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6403 char comm[TASK_COMM_LEN];
6406 memset(comm, 0, sizeof(comm));
6407 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6408 size = ALIGN(strlen(comm)+1, sizeof(u64));
6410 comm_event->comm = comm;
6411 comm_event->comm_size = size;
6413 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6415 perf_iterate_sb(perf_event_comm_output,
6420 void perf_event_comm(struct task_struct *task, bool exec)
6422 struct perf_comm_event comm_event;
6424 if (!atomic_read(&nr_comm_events))
6427 comm_event = (struct perf_comm_event){
6433 .type = PERF_RECORD_COMM,
6434 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6442 perf_event_comm_event(&comm_event);
6449 struct perf_mmap_event {
6450 struct vm_area_struct *vma;
6452 const char *file_name;
6460 struct perf_event_header header;
6470 static int perf_event_mmap_match(struct perf_event *event,
6473 struct perf_mmap_event *mmap_event = data;
6474 struct vm_area_struct *vma = mmap_event->vma;
6475 int executable = vma->vm_flags & VM_EXEC;
6477 return (!executable && event->attr.mmap_data) ||
6478 (executable && (event->attr.mmap || event->attr.mmap2));
6481 static void perf_event_mmap_output(struct perf_event *event,
6484 struct perf_mmap_event *mmap_event = data;
6485 struct perf_output_handle handle;
6486 struct perf_sample_data sample;
6487 int size = mmap_event->event_id.header.size;
6490 if (!perf_event_mmap_match(event, data))
6493 if (event->attr.mmap2) {
6494 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6495 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6496 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6497 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6498 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6499 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6500 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6503 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6504 ret = perf_output_begin(&handle, event,
6505 mmap_event->event_id.header.size);
6509 mmap_event->event_id.pid = perf_event_pid(event, current);
6510 mmap_event->event_id.tid = perf_event_tid(event, current);
6512 perf_output_put(&handle, mmap_event->event_id);
6514 if (event->attr.mmap2) {
6515 perf_output_put(&handle, mmap_event->maj);
6516 perf_output_put(&handle, mmap_event->min);
6517 perf_output_put(&handle, mmap_event->ino);
6518 perf_output_put(&handle, mmap_event->ino_generation);
6519 perf_output_put(&handle, mmap_event->prot);
6520 perf_output_put(&handle, mmap_event->flags);
6523 __output_copy(&handle, mmap_event->file_name,
6524 mmap_event->file_size);
6526 perf_event__output_id_sample(event, &handle, &sample);
6528 perf_output_end(&handle);
6530 mmap_event->event_id.header.size = size;
6533 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6535 struct vm_area_struct *vma = mmap_event->vma;
6536 struct file *file = vma->vm_file;
6537 int maj = 0, min = 0;
6538 u64 ino = 0, gen = 0;
6539 u32 prot = 0, flags = 0;
6546 struct inode *inode;
6549 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6555 * d_path() works from the end of the rb backwards, so we
6556 * need to add enough zero bytes after the string to handle
6557 * the 64bit alignment we do later.
6559 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6564 inode = file_inode(vma->vm_file);
6565 dev = inode->i_sb->s_dev;
6567 gen = inode->i_generation;
6571 if (vma->vm_flags & VM_READ)
6573 if (vma->vm_flags & VM_WRITE)
6575 if (vma->vm_flags & VM_EXEC)
6578 if (vma->vm_flags & VM_MAYSHARE)
6581 flags = MAP_PRIVATE;
6583 if (vma->vm_flags & VM_DENYWRITE)
6584 flags |= MAP_DENYWRITE;
6585 if (vma->vm_flags & VM_MAYEXEC)
6586 flags |= MAP_EXECUTABLE;
6587 if (vma->vm_flags & VM_LOCKED)
6588 flags |= MAP_LOCKED;
6589 if (vma->vm_flags & VM_HUGETLB)
6590 flags |= MAP_HUGETLB;
6594 if (vma->vm_ops && vma->vm_ops->name) {
6595 name = (char *) vma->vm_ops->name(vma);
6600 name = (char *)arch_vma_name(vma);
6604 if (vma->vm_start <= vma->vm_mm->start_brk &&
6605 vma->vm_end >= vma->vm_mm->brk) {
6609 if (vma->vm_start <= vma->vm_mm->start_stack &&
6610 vma->vm_end >= vma->vm_mm->start_stack) {
6620 strlcpy(tmp, name, sizeof(tmp));
6624 * Since our buffer works in 8 byte units we need to align our string
6625 * size to a multiple of 8. However, we must guarantee the tail end is
6626 * zero'd out to avoid leaking random bits to userspace.
6628 size = strlen(name)+1;
6629 while (!IS_ALIGNED(size, sizeof(u64)))
6630 name[size++] = '\0';
6632 mmap_event->file_name = name;
6633 mmap_event->file_size = size;
6634 mmap_event->maj = maj;
6635 mmap_event->min = min;
6636 mmap_event->ino = ino;
6637 mmap_event->ino_generation = gen;
6638 mmap_event->prot = prot;
6639 mmap_event->flags = flags;
6641 if (!(vma->vm_flags & VM_EXEC))
6642 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6644 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6646 perf_iterate_sb(perf_event_mmap_output,
6654 * Check whether inode and address range match filter criteria.
6656 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6657 struct file *file, unsigned long offset,
6660 if (filter->inode != file->f_inode)
6663 if (filter->offset > offset + size)
6666 if (filter->offset + filter->size < offset)
6672 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6674 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6675 struct vm_area_struct *vma = data;
6676 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6677 struct file *file = vma->vm_file;
6678 struct perf_addr_filter *filter;
6679 unsigned int restart = 0, count = 0;
6681 if (!has_addr_filter(event))
6687 raw_spin_lock_irqsave(&ifh->lock, flags);
6688 list_for_each_entry(filter, &ifh->list, entry) {
6689 if (perf_addr_filter_match(filter, file, off,
6690 vma->vm_end - vma->vm_start)) {
6691 event->addr_filters_offs[count] = vma->vm_start;
6699 event->addr_filters_gen++;
6700 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6703 perf_event_restart(event);
6707 * Adjust all task's events' filters to the new vma
6709 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6711 struct perf_event_context *ctx;
6715 * Data tracing isn't supported yet and as such there is no need
6716 * to keep track of anything that isn't related to executable code:
6718 if (!(vma->vm_flags & VM_EXEC))
6722 for_each_task_context_nr(ctxn) {
6723 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6727 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6732 void perf_event_mmap(struct vm_area_struct *vma)
6734 struct perf_mmap_event mmap_event;
6736 if (!atomic_read(&nr_mmap_events))
6739 mmap_event = (struct perf_mmap_event){
6745 .type = PERF_RECORD_MMAP,
6746 .misc = PERF_RECORD_MISC_USER,
6751 .start = vma->vm_start,
6752 .len = vma->vm_end - vma->vm_start,
6753 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6755 /* .maj (attr_mmap2 only) */
6756 /* .min (attr_mmap2 only) */
6757 /* .ino (attr_mmap2 only) */
6758 /* .ino_generation (attr_mmap2 only) */
6759 /* .prot (attr_mmap2 only) */
6760 /* .flags (attr_mmap2 only) */
6763 perf_addr_filters_adjust(vma);
6764 perf_event_mmap_event(&mmap_event);
6767 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6768 unsigned long size, u64 flags)
6770 struct perf_output_handle handle;
6771 struct perf_sample_data sample;
6772 struct perf_aux_event {
6773 struct perf_event_header header;
6779 .type = PERF_RECORD_AUX,
6781 .size = sizeof(rec),
6789 perf_event_header__init_id(&rec.header, &sample, event);
6790 ret = perf_output_begin(&handle, event, rec.header.size);
6795 perf_output_put(&handle, rec);
6796 perf_event__output_id_sample(event, &handle, &sample);
6798 perf_output_end(&handle);
6802 * Lost/dropped samples logging
6804 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6806 struct perf_output_handle handle;
6807 struct perf_sample_data sample;
6811 struct perf_event_header header;
6813 } lost_samples_event = {
6815 .type = PERF_RECORD_LOST_SAMPLES,
6817 .size = sizeof(lost_samples_event),
6822 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6824 ret = perf_output_begin(&handle, event,
6825 lost_samples_event.header.size);
6829 perf_output_put(&handle, lost_samples_event);
6830 perf_event__output_id_sample(event, &handle, &sample);
6831 perf_output_end(&handle);
6835 * context_switch tracking
6838 struct perf_switch_event {
6839 struct task_struct *task;
6840 struct task_struct *next_prev;
6843 struct perf_event_header header;
6849 static int perf_event_switch_match(struct perf_event *event)
6851 return event->attr.context_switch;
6854 static void perf_event_switch_output(struct perf_event *event, void *data)
6856 struct perf_switch_event *se = data;
6857 struct perf_output_handle handle;
6858 struct perf_sample_data sample;
6861 if (!perf_event_switch_match(event))
6864 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6865 if (event->ctx->task) {
6866 se->event_id.header.type = PERF_RECORD_SWITCH;
6867 se->event_id.header.size = sizeof(se->event_id.header);
6869 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6870 se->event_id.header.size = sizeof(se->event_id);
6871 se->event_id.next_prev_pid =
6872 perf_event_pid(event, se->next_prev);
6873 se->event_id.next_prev_tid =
6874 perf_event_tid(event, se->next_prev);
6877 perf_event_header__init_id(&se->event_id.header, &sample, event);
6879 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6883 if (event->ctx->task)
6884 perf_output_put(&handle, se->event_id.header);
6886 perf_output_put(&handle, se->event_id);
6888 perf_event__output_id_sample(event, &handle, &sample);
6890 perf_output_end(&handle);
6893 static void perf_event_switch(struct task_struct *task,
6894 struct task_struct *next_prev, bool sched_in)
6896 struct perf_switch_event switch_event;
6898 /* N.B. caller checks nr_switch_events != 0 */
6900 switch_event = (struct perf_switch_event){
6902 .next_prev = next_prev,
6906 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6909 /* .next_prev_pid */
6910 /* .next_prev_tid */
6914 perf_iterate_sb(perf_event_switch_output,
6920 * IRQ throttle logging
6923 static void perf_log_throttle(struct perf_event *event, int enable)
6925 struct perf_output_handle handle;
6926 struct perf_sample_data sample;
6930 struct perf_event_header header;
6934 } throttle_event = {
6936 .type = PERF_RECORD_THROTTLE,
6938 .size = sizeof(throttle_event),
6940 .time = perf_event_clock(event),
6941 .id = primary_event_id(event),
6942 .stream_id = event->id,
6946 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6948 perf_event_header__init_id(&throttle_event.header, &sample, event);
6950 ret = perf_output_begin(&handle, event,
6951 throttle_event.header.size);
6955 perf_output_put(&handle, throttle_event);
6956 perf_event__output_id_sample(event, &handle, &sample);
6957 perf_output_end(&handle);
6960 static void perf_log_itrace_start(struct perf_event *event)
6962 struct perf_output_handle handle;
6963 struct perf_sample_data sample;
6964 struct perf_aux_event {
6965 struct perf_event_header header;
6972 event = event->parent;
6974 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6975 event->hw.itrace_started)
6978 rec.header.type = PERF_RECORD_ITRACE_START;
6979 rec.header.misc = 0;
6980 rec.header.size = sizeof(rec);
6981 rec.pid = perf_event_pid(event, current);
6982 rec.tid = perf_event_tid(event, current);
6984 perf_event_header__init_id(&rec.header, &sample, event);
6985 ret = perf_output_begin(&handle, event, rec.header.size);
6990 perf_output_put(&handle, rec);
6991 perf_event__output_id_sample(event, &handle, &sample);
6993 perf_output_end(&handle);
6997 * Generic event overflow handling, sampling.
7000 static int __perf_event_overflow(struct perf_event *event,
7001 int throttle, struct perf_sample_data *data,
7002 struct pt_regs *regs)
7004 int events = atomic_read(&event->event_limit);
7005 struct hw_perf_event *hwc = &event->hw;
7010 * Non-sampling counters might still use the PMI to fold short
7011 * hardware counters, ignore those.
7013 if (unlikely(!is_sampling_event(event)))
7016 seq = __this_cpu_read(perf_throttled_seq);
7017 if (seq != hwc->interrupts_seq) {
7018 hwc->interrupts_seq = seq;
7019 hwc->interrupts = 1;
7022 if (unlikely(throttle
7023 && hwc->interrupts >= max_samples_per_tick)) {
7024 __this_cpu_inc(perf_throttled_count);
7025 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7026 hwc->interrupts = MAX_INTERRUPTS;
7027 perf_log_throttle(event, 0);
7032 if (event->attr.freq) {
7033 u64 now = perf_clock();
7034 s64 delta = now - hwc->freq_time_stamp;
7036 hwc->freq_time_stamp = now;
7038 if (delta > 0 && delta < 2*TICK_NSEC)
7039 perf_adjust_period(event, delta, hwc->last_period, true);
7043 * XXX event_limit might not quite work as expected on inherited
7047 event->pending_kill = POLL_IN;
7048 if (events && atomic_dec_and_test(&event->event_limit)) {
7050 event->pending_kill = POLL_HUP;
7051 event->pending_disable = 1;
7052 irq_work_queue(&event->pending);
7055 event->overflow_handler(event, data, regs);
7057 if (*perf_event_fasync(event) && event->pending_kill) {
7058 event->pending_wakeup = 1;
7059 irq_work_queue(&event->pending);
7065 int perf_event_overflow(struct perf_event *event,
7066 struct perf_sample_data *data,
7067 struct pt_regs *regs)
7069 return __perf_event_overflow(event, 1, data, regs);
7073 * Generic software event infrastructure
7076 struct swevent_htable {
7077 struct swevent_hlist *swevent_hlist;
7078 struct mutex hlist_mutex;
7081 /* Recursion avoidance in each contexts */
7082 int recursion[PERF_NR_CONTEXTS];
7085 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7088 * We directly increment event->count and keep a second value in
7089 * event->hw.period_left to count intervals. This period event
7090 * is kept in the range [-sample_period, 0] so that we can use the
7094 u64 perf_swevent_set_period(struct perf_event *event)
7096 struct hw_perf_event *hwc = &event->hw;
7097 u64 period = hwc->last_period;
7101 hwc->last_period = hwc->sample_period;
7104 old = val = local64_read(&hwc->period_left);
7108 nr = div64_u64(period + val, period);
7109 offset = nr * period;
7111 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7117 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7118 struct perf_sample_data *data,
7119 struct pt_regs *regs)
7121 struct hw_perf_event *hwc = &event->hw;
7125 overflow = perf_swevent_set_period(event);
7127 if (hwc->interrupts == MAX_INTERRUPTS)
7130 for (; overflow; overflow--) {
7131 if (__perf_event_overflow(event, throttle,
7134 * We inhibit the overflow from happening when
7135 * hwc->interrupts == MAX_INTERRUPTS.
7143 static void perf_swevent_event(struct perf_event *event, u64 nr,
7144 struct perf_sample_data *data,
7145 struct pt_regs *regs)
7147 struct hw_perf_event *hwc = &event->hw;
7149 local64_add(nr, &event->count);
7154 if (!is_sampling_event(event))
7157 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7159 return perf_swevent_overflow(event, 1, data, regs);
7161 data->period = event->hw.last_period;
7163 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7164 return perf_swevent_overflow(event, 1, data, regs);
7166 if (local64_add_negative(nr, &hwc->period_left))
7169 perf_swevent_overflow(event, 0, data, regs);
7172 static int perf_exclude_event(struct perf_event *event,
7173 struct pt_regs *regs)
7175 if (event->hw.state & PERF_HES_STOPPED)
7179 if (event->attr.exclude_user && user_mode(regs))
7182 if (event->attr.exclude_kernel && !user_mode(regs))
7189 static int perf_swevent_match(struct perf_event *event,
7190 enum perf_type_id type,
7192 struct perf_sample_data *data,
7193 struct pt_regs *regs)
7195 if (event->attr.type != type)
7198 if (event->attr.config != event_id)
7201 if (perf_exclude_event(event, regs))
7207 static inline u64 swevent_hash(u64 type, u32 event_id)
7209 u64 val = event_id | (type << 32);
7211 return hash_64(val, SWEVENT_HLIST_BITS);
7214 static inline struct hlist_head *
7215 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7217 u64 hash = swevent_hash(type, event_id);
7219 return &hlist->heads[hash];
7222 /* For the read side: events when they trigger */
7223 static inline struct hlist_head *
7224 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7226 struct swevent_hlist *hlist;
7228 hlist = rcu_dereference(swhash->swevent_hlist);
7232 return __find_swevent_head(hlist, type, event_id);
7235 /* For the event head insertion and removal in the hlist */
7236 static inline struct hlist_head *
7237 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7239 struct swevent_hlist *hlist;
7240 u32 event_id = event->attr.config;
7241 u64 type = event->attr.type;
7244 * Event scheduling is always serialized against hlist allocation
7245 * and release. Which makes the protected version suitable here.
7246 * The context lock guarantees that.
7248 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7249 lockdep_is_held(&event->ctx->lock));
7253 return __find_swevent_head(hlist, type, event_id);
7256 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7258 struct perf_sample_data *data,
7259 struct pt_regs *regs)
7261 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7262 struct perf_event *event;
7263 struct hlist_head *head;
7266 head = find_swevent_head_rcu(swhash, type, event_id);
7270 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7271 if (perf_swevent_match(event, type, event_id, data, regs))
7272 perf_swevent_event(event, nr, data, regs);
7278 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7280 int perf_swevent_get_recursion_context(void)
7282 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7284 return get_recursion_context(swhash->recursion);
7286 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7288 void perf_swevent_put_recursion_context(int rctx)
7290 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7292 put_recursion_context(swhash->recursion, rctx);
7295 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7297 struct perf_sample_data data;
7299 if (WARN_ON_ONCE(!regs))
7302 perf_sample_data_init(&data, addr, 0);
7303 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7306 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7310 preempt_disable_notrace();
7311 rctx = perf_swevent_get_recursion_context();
7312 if (unlikely(rctx < 0))
7315 ___perf_sw_event(event_id, nr, regs, addr);
7317 perf_swevent_put_recursion_context(rctx);
7319 preempt_enable_notrace();
7322 static void perf_swevent_read(struct perf_event *event)
7326 static int perf_swevent_add(struct perf_event *event, int flags)
7328 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7329 struct hw_perf_event *hwc = &event->hw;
7330 struct hlist_head *head;
7332 if (is_sampling_event(event)) {
7333 hwc->last_period = hwc->sample_period;
7334 perf_swevent_set_period(event);
7337 hwc->state = !(flags & PERF_EF_START);
7339 head = find_swevent_head(swhash, event);
7340 if (WARN_ON_ONCE(!head))
7343 hlist_add_head_rcu(&event->hlist_entry, head);
7344 perf_event_update_userpage(event);
7349 static void perf_swevent_del(struct perf_event *event, int flags)
7351 hlist_del_rcu(&event->hlist_entry);
7354 static void perf_swevent_start(struct perf_event *event, int flags)
7356 event->hw.state = 0;
7359 static void perf_swevent_stop(struct perf_event *event, int flags)
7361 event->hw.state = PERF_HES_STOPPED;
7364 /* Deref the hlist from the update side */
7365 static inline struct swevent_hlist *
7366 swevent_hlist_deref(struct swevent_htable *swhash)
7368 return rcu_dereference_protected(swhash->swevent_hlist,
7369 lockdep_is_held(&swhash->hlist_mutex));
7372 static void swevent_hlist_release(struct swevent_htable *swhash)
7374 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7379 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7380 kfree_rcu(hlist, rcu_head);
7383 static void swevent_hlist_put_cpu(int cpu)
7385 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7387 mutex_lock(&swhash->hlist_mutex);
7389 if (!--swhash->hlist_refcount)
7390 swevent_hlist_release(swhash);
7392 mutex_unlock(&swhash->hlist_mutex);
7395 static void swevent_hlist_put(void)
7399 for_each_possible_cpu(cpu)
7400 swevent_hlist_put_cpu(cpu);
7403 static int swevent_hlist_get_cpu(int cpu)
7405 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7408 mutex_lock(&swhash->hlist_mutex);
7409 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7410 struct swevent_hlist *hlist;
7412 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7417 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7419 swhash->hlist_refcount++;
7421 mutex_unlock(&swhash->hlist_mutex);
7426 static int swevent_hlist_get(void)
7428 int err, cpu, failed_cpu;
7431 for_each_possible_cpu(cpu) {
7432 err = swevent_hlist_get_cpu(cpu);
7442 for_each_possible_cpu(cpu) {
7443 if (cpu == failed_cpu)
7445 swevent_hlist_put_cpu(cpu);
7452 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7454 static void sw_perf_event_destroy(struct perf_event *event)
7456 u64 event_id = event->attr.config;
7458 WARN_ON(event->parent);
7460 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7461 swevent_hlist_put();
7464 static int perf_swevent_init(struct perf_event *event)
7466 u64 event_id = event->attr.config;
7468 if (event->attr.type != PERF_TYPE_SOFTWARE)
7472 * no branch sampling for software events
7474 if (has_branch_stack(event))
7478 case PERF_COUNT_SW_CPU_CLOCK:
7479 case PERF_COUNT_SW_TASK_CLOCK:
7486 if (event_id >= PERF_COUNT_SW_MAX)
7489 if (!event->parent) {
7492 err = swevent_hlist_get();
7496 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7497 event->destroy = sw_perf_event_destroy;
7503 static struct pmu perf_swevent = {
7504 .task_ctx_nr = perf_sw_context,
7506 .capabilities = PERF_PMU_CAP_NO_NMI,
7508 .event_init = perf_swevent_init,
7509 .add = perf_swevent_add,
7510 .del = perf_swevent_del,
7511 .start = perf_swevent_start,
7512 .stop = perf_swevent_stop,
7513 .read = perf_swevent_read,
7516 #ifdef CONFIG_EVENT_TRACING
7518 static int perf_tp_filter_match(struct perf_event *event,
7519 struct perf_sample_data *data)
7521 void *record = data->raw->frag.data;
7523 /* only top level events have filters set */
7525 event = event->parent;
7527 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7532 static int perf_tp_event_match(struct perf_event *event,
7533 struct perf_sample_data *data,
7534 struct pt_regs *regs)
7536 if (event->hw.state & PERF_HES_STOPPED)
7539 * All tracepoints are from kernel-space.
7541 if (event->attr.exclude_kernel)
7544 if (!perf_tp_filter_match(event, data))
7550 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7551 struct trace_event_call *call, u64 count,
7552 struct pt_regs *regs, struct hlist_head *head,
7553 struct task_struct *task)
7555 struct bpf_prog *prog = call->prog;
7558 *(struct pt_regs **)raw_data = regs;
7559 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7560 perf_swevent_put_recursion_context(rctx);
7564 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7567 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7569 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7570 struct pt_regs *regs, struct hlist_head *head, int rctx,
7571 struct task_struct *task)
7573 struct perf_sample_data data;
7574 struct perf_event *event;
7576 struct perf_raw_record raw = {
7583 perf_sample_data_init(&data, 0, 0);
7586 perf_trace_buf_update(record, event_type);
7588 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7589 if (perf_tp_event_match(event, &data, regs))
7590 perf_swevent_event(event, count, &data, regs);
7594 * If we got specified a target task, also iterate its context and
7595 * deliver this event there too.
7597 if (task && task != current) {
7598 struct perf_event_context *ctx;
7599 struct trace_entry *entry = record;
7602 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7606 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7607 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7609 if (event->attr.config != entry->type)
7611 if (perf_tp_event_match(event, &data, regs))
7612 perf_swevent_event(event, count, &data, regs);
7618 perf_swevent_put_recursion_context(rctx);
7620 EXPORT_SYMBOL_GPL(perf_tp_event);
7622 static void tp_perf_event_destroy(struct perf_event *event)
7624 perf_trace_destroy(event);
7627 static int perf_tp_event_init(struct perf_event *event)
7631 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7635 * no branch sampling for tracepoint events
7637 if (has_branch_stack(event))
7640 err = perf_trace_init(event);
7644 event->destroy = tp_perf_event_destroy;
7649 static struct pmu perf_tracepoint = {
7650 .task_ctx_nr = perf_sw_context,
7652 .event_init = perf_tp_event_init,
7653 .add = perf_trace_add,
7654 .del = perf_trace_del,
7655 .start = perf_swevent_start,
7656 .stop = perf_swevent_stop,
7657 .read = perf_swevent_read,
7660 static inline void perf_tp_register(void)
7662 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7665 static void perf_event_free_filter(struct perf_event *event)
7667 ftrace_profile_free_filter(event);
7670 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7672 bool is_kprobe, is_tracepoint;
7673 struct bpf_prog *prog;
7675 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7678 if (event->tp_event->prog)
7681 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7682 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7683 if (!is_kprobe && !is_tracepoint)
7684 /* bpf programs can only be attached to u/kprobe or tracepoint */
7687 prog = bpf_prog_get(prog_fd);
7689 return PTR_ERR(prog);
7691 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7692 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7693 /* valid fd, but invalid bpf program type */
7698 if (is_tracepoint) {
7699 int off = trace_event_get_offsets(event->tp_event);
7701 if (prog->aux->max_ctx_offset > off) {
7706 event->tp_event->prog = prog;
7711 static void perf_event_free_bpf_prog(struct perf_event *event)
7713 struct bpf_prog *prog;
7715 if (!event->tp_event)
7718 prog = event->tp_event->prog;
7720 event->tp_event->prog = NULL;
7727 static inline void perf_tp_register(void)
7731 static void perf_event_free_filter(struct perf_event *event)
7735 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7740 static void perf_event_free_bpf_prog(struct perf_event *event)
7743 #endif /* CONFIG_EVENT_TRACING */
7745 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7746 void perf_bp_event(struct perf_event *bp, void *data)
7748 struct perf_sample_data sample;
7749 struct pt_regs *regs = data;
7751 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7753 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7754 perf_swevent_event(bp, 1, &sample, regs);
7759 * Allocate a new address filter
7761 static struct perf_addr_filter *
7762 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7764 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7765 struct perf_addr_filter *filter;
7767 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7771 INIT_LIST_HEAD(&filter->entry);
7772 list_add_tail(&filter->entry, filters);
7777 static void free_filters_list(struct list_head *filters)
7779 struct perf_addr_filter *filter, *iter;
7781 list_for_each_entry_safe(filter, iter, filters, entry) {
7783 iput(filter->inode);
7784 list_del(&filter->entry);
7790 * Free existing address filters and optionally install new ones
7792 static void perf_addr_filters_splice(struct perf_event *event,
7793 struct list_head *head)
7795 unsigned long flags;
7798 if (!has_addr_filter(event))
7801 /* don't bother with children, they don't have their own filters */
7805 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7807 list_splice_init(&event->addr_filters.list, &list);
7809 list_splice(head, &event->addr_filters.list);
7811 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7813 free_filters_list(&list);
7817 * Scan through mm's vmas and see if one of them matches the
7818 * @filter; if so, adjust filter's address range.
7819 * Called with mm::mmap_sem down for reading.
7821 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
7822 struct mm_struct *mm)
7824 struct vm_area_struct *vma;
7826 for (vma = mm->mmap; vma; vma = vma->vm_next) {
7827 struct file *file = vma->vm_file;
7828 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7829 unsigned long vma_size = vma->vm_end - vma->vm_start;
7834 if (!perf_addr_filter_match(filter, file, off, vma_size))
7837 return vma->vm_start;
7844 * Update event's address range filters based on the
7845 * task's existing mappings, if any.
7847 static void perf_event_addr_filters_apply(struct perf_event *event)
7849 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7850 struct task_struct *task = READ_ONCE(event->ctx->task);
7851 struct perf_addr_filter *filter;
7852 struct mm_struct *mm = NULL;
7853 unsigned int count = 0;
7854 unsigned long flags;
7857 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7858 * will stop on the parent's child_mutex that our caller is also holding
7860 if (task == TASK_TOMBSTONE)
7863 mm = get_task_mm(event->ctx->task);
7867 down_read(&mm->mmap_sem);
7869 raw_spin_lock_irqsave(&ifh->lock, flags);
7870 list_for_each_entry(filter, &ifh->list, entry) {
7871 event->addr_filters_offs[count] = 0;
7874 * Adjust base offset if the filter is associated to a binary
7875 * that needs to be mapped:
7878 event->addr_filters_offs[count] =
7879 perf_addr_filter_apply(filter, mm);
7884 event->addr_filters_gen++;
7885 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7887 up_read(&mm->mmap_sem);
7892 perf_event_restart(event);
7896 * Address range filtering: limiting the data to certain
7897 * instruction address ranges. Filters are ioctl()ed to us from
7898 * userspace as ascii strings.
7900 * Filter string format:
7903 * where ACTION is one of the
7904 * * "filter": limit the trace to this region
7905 * * "start": start tracing from this address
7906 * * "stop": stop tracing at this address/region;
7908 * * for kernel addresses: <start address>[/<size>]
7909 * * for object files: <start address>[/<size>]@</path/to/object/file>
7911 * if <size> is not specified, the range is treated as a single address.
7924 IF_STATE_ACTION = 0,
7929 static const match_table_t if_tokens = {
7930 { IF_ACT_FILTER, "filter" },
7931 { IF_ACT_START, "start" },
7932 { IF_ACT_STOP, "stop" },
7933 { IF_SRC_FILE, "%u/%u@%s" },
7934 { IF_SRC_KERNEL, "%u/%u" },
7935 { IF_SRC_FILEADDR, "%u@%s" },
7936 { IF_SRC_KERNELADDR, "%u" },
7940 * Address filter string parser
7943 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
7944 struct list_head *filters)
7946 struct perf_addr_filter *filter = NULL;
7947 char *start, *orig, *filename = NULL;
7949 substring_t args[MAX_OPT_ARGS];
7950 int state = IF_STATE_ACTION, token;
7951 unsigned int kernel = 0;
7954 orig = fstr = kstrdup(fstr, GFP_KERNEL);
7958 while ((start = strsep(&fstr, " ,\n")) != NULL) {
7964 /* filter definition begins */
7965 if (state == IF_STATE_ACTION) {
7966 filter = perf_addr_filter_new(event, filters);
7971 token = match_token(start, if_tokens, args);
7978 if (state != IF_STATE_ACTION)
7981 state = IF_STATE_SOURCE;
7984 case IF_SRC_KERNELADDR:
7988 case IF_SRC_FILEADDR:
7990 if (state != IF_STATE_SOURCE)
7993 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
7997 ret = kstrtoul(args[0].from, 0, &filter->offset);
8001 if (filter->range) {
8003 ret = kstrtoul(args[1].from, 0, &filter->size);
8008 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8009 int fpos = filter->range ? 2 : 1;
8011 filename = match_strdup(&args[fpos]);
8018 state = IF_STATE_END;
8026 * Filter definition is fully parsed, validate and install it.
8027 * Make sure that it doesn't contradict itself or the event's
8030 if (state == IF_STATE_END) {
8031 if (kernel && event->attr.exclude_kernel)
8038 /* look up the path and grab its inode */
8039 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8041 goto fail_free_name;
8043 filter->inode = igrab(d_inode(path.dentry));
8049 if (!filter->inode ||
8050 !S_ISREG(filter->inode->i_mode))
8051 /* free_filters_list() will iput() */
8055 /* ready to consume more filters */
8056 state = IF_STATE_ACTION;
8061 if (state != IF_STATE_ACTION)
8071 free_filters_list(filters);
8078 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8084 * Since this is called in perf_ioctl() path, we're already holding
8087 lockdep_assert_held(&event->ctx->mutex);
8089 if (WARN_ON_ONCE(event->parent))
8093 * For now, we only support filtering in per-task events; doing so
8094 * for CPU-wide events requires additional context switching trickery,
8095 * since same object code will be mapped at different virtual
8096 * addresses in different processes.
8098 if (!event->ctx->task)
8101 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8105 ret = event->pmu->addr_filters_validate(&filters);
8107 free_filters_list(&filters);
8111 /* remove existing filters, if any */
8112 perf_addr_filters_splice(event, &filters);
8114 /* install new filters */
8115 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8120 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8125 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8126 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8127 !has_addr_filter(event))
8130 filter_str = strndup_user(arg, PAGE_SIZE);
8131 if (IS_ERR(filter_str))
8132 return PTR_ERR(filter_str);
8134 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8135 event->attr.type == PERF_TYPE_TRACEPOINT)
8136 ret = ftrace_profile_set_filter(event, event->attr.config,
8138 else if (has_addr_filter(event))
8139 ret = perf_event_set_addr_filter(event, filter_str);
8146 * hrtimer based swevent callback
8149 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8151 enum hrtimer_restart ret = HRTIMER_RESTART;
8152 struct perf_sample_data data;
8153 struct pt_regs *regs;
8154 struct perf_event *event;
8157 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8159 if (event->state != PERF_EVENT_STATE_ACTIVE)
8160 return HRTIMER_NORESTART;
8162 event->pmu->read(event);
8164 perf_sample_data_init(&data, 0, event->hw.last_period);
8165 regs = get_irq_regs();
8167 if (regs && !perf_exclude_event(event, regs)) {
8168 if (!(event->attr.exclude_idle && is_idle_task(current)))
8169 if (__perf_event_overflow(event, 1, &data, regs))
8170 ret = HRTIMER_NORESTART;
8173 period = max_t(u64, 10000, event->hw.sample_period);
8174 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8179 static void perf_swevent_start_hrtimer(struct perf_event *event)
8181 struct hw_perf_event *hwc = &event->hw;
8184 if (!is_sampling_event(event))
8187 period = local64_read(&hwc->period_left);
8192 local64_set(&hwc->period_left, 0);
8194 period = max_t(u64, 10000, hwc->sample_period);
8196 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8197 HRTIMER_MODE_REL_PINNED);
8200 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8202 struct hw_perf_event *hwc = &event->hw;
8204 if (is_sampling_event(event)) {
8205 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8206 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8208 hrtimer_cancel(&hwc->hrtimer);
8212 static void perf_swevent_init_hrtimer(struct perf_event *event)
8214 struct hw_perf_event *hwc = &event->hw;
8216 if (!is_sampling_event(event))
8219 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8220 hwc->hrtimer.function = perf_swevent_hrtimer;
8223 * Since hrtimers have a fixed rate, we can do a static freq->period
8224 * mapping and avoid the whole period adjust feedback stuff.
8226 if (event->attr.freq) {
8227 long freq = event->attr.sample_freq;
8229 event->attr.sample_period = NSEC_PER_SEC / freq;
8230 hwc->sample_period = event->attr.sample_period;
8231 local64_set(&hwc->period_left, hwc->sample_period);
8232 hwc->last_period = hwc->sample_period;
8233 event->attr.freq = 0;
8238 * Software event: cpu wall time clock
8241 static void cpu_clock_event_update(struct perf_event *event)
8246 now = local_clock();
8247 prev = local64_xchg(&event->hw.prev_count, now);
8248 local64_add(now - prev, &event->count);
8251 static void cpu_clock_event_start(struct perf_event *event, int flags)
8253 local64_set(&event->hw.prev_count, local_clock());
8254 perf_swevent_start_hrtimer(event);
8257 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8259 perf_swevent_cancel_hrtimer(event);
8260 cpu_clock_event_update(event);
8263 static int cpu_clock_event_add(struct perf_event *event, int flags)
8265 if (flags & PERF_EF_START)
8266 cpu_clock_event_start(event, flags);
8267 perf_event_update_userpage(event);
8272 static void cpu_clock_event_del(struct perf_event *event, int flags)
8274 cpu_clock_event_stop(event, flags);
8277 static void cpu_clock_event_read(struct perf_event *event)
8279 cpu_clock_event_update(event);
8282 static int cpu_clock_event_init(struct perf_event *event)
8284 if (event->attr.type != PERF_TYPE_SOFTWARE)
8287 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8291 * no branch sampling for software events
8293 if (has_branch_stack(event))
8296 perf_swevent_init_hrtimer(event);
8301 static struct pmu perf_cpu_clock = {
8302 .task_ctx_nr = perf_sw_context,
8304 .capabilities = PERF_PMU_CAP_NO_NMI,
8306 .event_init = cpu_clock_event_init,
8307 .add = cpu_clock_event_add,
8308 .del = cpu_clock_event_del,
8309 .start = cpu_clock_event_start,
8310 .stop = cpu_clock_event_stop,
8311 .read = cpu_clock_event_read,
8315 * Software event: task time clock
8318 static void task_clock_event_update(struct perf_event *event, u64 now)
8323 prev = local64_xchg(&event->hw.prev_count, now);
8325 local64_add(delta, &event->count);
8328 static void task_clock_event_start(struct perf_event *event, int flags)
8330 local64_set(&event->hw.prev_count, event->ctx->time);
8331 perf_swevent_start_hrtimer(event);
8334 static void task_clock_event_stop(struct perf_event *event, int flags)
8336 perf_swevent_cancel_hrtimer(event);
8337 task_clock_event_update(event, event->ctx->time);
8340 static int task_clock_event_add(struct perf_event *event, int flags)
8342 if (flags & PERF_EF_START)
8343 task_clock_event_start(event, flags);
8344 perf_event_update_userpage(event);
8349 static void task_clock_event_del(struct perf_event *event, int flags)
8351 task_clock_event_stop(event, PERF_EF_UPDATE);
8354 static void task_clock_event_read(struct perf_event *event)
8356 u64 now = perf_clock();
8357 u64 delta = now - event->ctx->timestamp;
8358 u64 time = event->ctx->time + delta;
8360 task_clock_event_update(event, time);
8363 static int task_clock_event_init(struct perf_event *event)
8365 if (event->attr.type != PERF_TYPE_SOFTWARE)
8368 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8372 * no branch sampling for software events
8374 if (has_branch_stack(event))
8377 perf_swevent_init_hrtimer(event);
8382 static struct pmu perf_task_clock = {
8383 .task_ctx_nr = perf_sw_context,
8385 .capabilities = PERF_PMU_CAP_NO_NMI,
8387 .event_init = task_clock_event_init,
8388 .add = task_clock_event_add,
8389 .del = task_clock_event_del,
8390 .start = task_clock_event_start,
8391 .stop = task_clock_event_stop,
8392 .read = task_clock_event_read,
8395 static void perf_pmu_nop_void(struct pmu *pmu)
8399 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8403 static int perf_pmu_nop_int(struct pmu *pmu)
8408 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8410 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8412 __this_cpu_write(nop_txn_flags, flags);
8414 if (flags & ~PERF_PMU_TXN_ADD)
8417 perf_pmu_disable(pmu);
8420 static int perf_pmu_commit_txn(struct pmu *pmu)
8422 unsigned int flags = __this_cpu_read(nop_txn_flags);
8424 __this_cpu_write(nop_txn_flags, 0);
8426 if (flags & ~PERF_PMU_TXN_ADD)
8429 perf_pmu_enable(pmu);
8433 static void perf_pmu_cancel_txn(struct pmu *pmu)
8435 unsigned int flags = __this_cpu_read(nop_txn_flags);
8437 __this_cpu_write(nop_txn_flags, 0);
8439 if (flags & ~PERF_PMU_TXN_ADD)
8442 perf_pmu_enable(pmu);
8445 static int perf_event_idx_default(struct perf_event *event)
8451 * Ensures all contexts with the same task_ctx_nr have the same
8452 * pmu_cpu_context too.
8454 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8461 list_for_each_entry(pmu, &pmus, entry) {
8462 if (pmu->task_ctx_nr == ctxn)
8463 return pmu->pmu_cpu_context;
8469 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8473 for_each_possible_cpu(cpu) {
8474 struct perf_cpu_context *cpuctx;
8476 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8478 if (cpuctx->unique_pmu == old_pmu)
8479 cpuctx->unique_pmu = pmu;
8483 static void free_pmu_context(struct pmu *pmu)
8487 mutex_lock(&pmus_lock);
8489 * Like a real lame refcount.
8491 list_for_each_entry(i, &pmus, entry) {
8492 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8493 update_pmu_context(i, pmu);
8498 free_percpu(pmu->pmu_cpu_context);
8500 mutex_unlock(&pmus_lock);
8504 * Let userspace know that this PMU supports address range filtering:
8506 static ssize_t nr_addr_filters_show(struct device *dev,
8507 struct device_attribute *attr,
8510 struct pmu *pmu = dev_get_drvdata(dev);
8512 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8514 DEVICE_ATTR_RO(nr_addr_filters);
8516 static struct idr pmu_idr;
8519 type_show(struct device *dev, struct device_attribute *attr, char *page)
8521 struct pmu *pmu = dev_get_drvdata(dev);
8523 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8525 static DEVICE_ATTR_RO(type);
8528 perf_event_mux_interval_ms_show(struct device *dev,
8529 struct device_attribute *attr,
8532 struct pmu *pmu = dev_get_drvdata(dev);
8534 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8537 static DEFINE_MUTEX(mux_interval_mutex);
8540 perf_event_mux_interval_ms_store(struct device *dev,
8541 struct device_attribute *attr,
8542 const char *buf, size_t count)
8544 struct pmu *pmu = dev_get_drvdata(dev);
8545 int timer, cpu, ret;
8547 ret = kstrtoint(buf, 0, &timer);
8554 /* same value, noting to do */
8555 if (timer == pmu->hrtimer_interval_ms)
8558 mutex_lock(&mux_interval_mutex);
8559 pmu->hrtimer_interval_ms = timer;
8561 /* update all cpuctx for this PMU */
8563 for_each_online_cpu(cpu) {
8564 struct perf_cpu_context *cpuctx;
8565 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8566 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8568 cpu_function_call(cpu,
8569 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8572 mutex_unlock(&mux_interval_mutex);
8576 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8578 static struct attribute *pmu_dev_attrs[] = {
8579 &dev_attr_type.attr,
8580 &dev_attr_perf_event_mux_interval_ms.attr,
8583 ATTRIBUTE_GROUPS(pmu_dev);
8585 static int pmu_bus_running;
8586 static struct bus_type pmu_bus = {
8587 .name = "event_source",
8588 .dev_groups = pmu_dev_groups,
8591 static void pmu_dev_release(struct device *dev)
8596 static int pmu_dev_alloc(struct pmu *pmu)
8600 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8604 pmu->dev->groups = pmu->attr_groups;
8605 device_initialize(pmu->dev);
8606 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8610 dev_set_drvdata(pmu->dev, pmu);
8611 pmu->dev->bus = &pmu_bus;
8612 pmu->dev->release = pmu_dev_release;
8613 ret = device_add(pmu->dev);
8617 /* For PMUs with address filters, throw in an extra attribute: */
8618 if (pmu->nr_addr_filters)
8619 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8628 device_del(pmu->dev);
8631 put_device(pmu->dev);
8635 static struct lock_class_key cpuctx_mutex;
8636 static struct lock_class_key cpuctx_lock;
8638 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8642 mutex_lock(&pmus_lock);
8644 pmu->pmu_disable_count = alloc_percpu(int);
8645 if (!pmu->pmu_disable_count)
8654 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8662 if (pmu_bus_running) {
8663 ret = pmu_dev_alloc(pmu);
8669 if (pmu->task_ctx_nr == perf_hw_context) {
8670 static int hw_context_taken = 0;
8673 * Other than systems with heterogeneous CPUs, it never makes
8674 * sense for two PMUs to share perf_hw_context. PMUs which are
8675 * uncore must use perf_invalid_context.
8677 if (WARN_ON_ONCE(hw_context_taken &&
8678 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8679 pmu->task_ctx_nr = perf_invalid_context;
8681 hw_context_taken = 1;
8684 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8685 if (pmu->pmu_cpu_context)
8686 goto got_cpu_context;
8689 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8690 if (!pmu->pmu_cpu_context)
8693 for_each_possible_cpu(cpu) {
8694 struct perf_cpu_context *cpuctx;
8696 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8697 __perf_event_init_context(&cpuctx->ctx);
8698 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8699 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8700 cpuctx->ctx.pmu = pmu;
8702 __perf_mux_hrtimer_init(cpuctx, cpu);
8704 cpuctx->unique_pmu = pmu;
8708 if (!pmu->start_txn) {
8709 if (pmu->pmu_enable) {
8711 * If we have pmu_enable/pmu_disable calls, install
8712 * transaction stubs that use that to try and batch
8713 * hardware accesses.
8715 pmu->start_txn = perf_pmu_start_txn;
8716 pmu->commit_txn = perf_pmu_commit_txn;
8717 pmu->cancel_txn = perf_pmu_cancel_txn;
8719 pmu->start_txn = perf_pmu_nop_txn;
8720 pmu->commit_txn = perf_pmu_nop_int;
8721 pmu->cancel_txn = perf_pmu_nop_void;
8725 if (!pmu->pmu_enable) {
8726 pmu->pmu_enable = perf_pmu_nop_void;
8727 pmu->pmu_disable = perf_pmu_nop_void;
8730 if (!pmu->event_idx)
8731 pmu->event_idx = perf_event_idx_default;
8733 list_add_rcu(&pmu->entry, &pmus);
8734 atomic_set(&pmu->exclusive_cnt, 0);
8737 mutex_unlock(&pmus_lock);
8742 device_del(pmu->dev);
8743 put_device(pmu->dev);
8746 if (pmu->type >= PERF_TYPE_MAX)
8747 idr_remove(&pmu_idr, pmu->type);
8750 free_percpu(pmu->pmu_disable_count);
8753 EXPORT_SYMBOL_GPL(perf_pmu_register);
8755 void perf_pmu_unregister(struct pmu *pmu)
8757 mutex_lock(&pmus_lock);
8758 list_del_rcu(&pmu->entry);
8759 mutex_unlock(&pmus_lock);
8762 * We dereference the pmu list under both SRCU and regular RCU, so
8763 * synchronize against both of those.
8765 synchronize_srcu(&pmus_srcu);
8768 free_percpu(pmu->pmu_disable_count);
8769 if (pmu->type >= PERF_TYPE_MAX)
8770 idr_remove(&pmu_idr, pmu->type);
8771 if (pmu->nr_addr_filters)
8772 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8773 device_del(pmu->dev);
8774 put_device(pmu->dev);
8775 free_pmu_context(pmu);
8777 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8779 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8781 struct perf_event_context *ctx = NULL;
8784 if (!try_module_get(pmu->module))
8787 if (event->group_leader != event) {
8789 * This ctx->mutex can nest when we're called through
8790 * inheritance. See the perf_event_ctx_lock_nested() comment.
8792 ctx = perf_event_ctx_lock_nested(event->group_leader,
8793 SINGLE_DEPTH_NESTING);
8798 ret = pmu->event_init(event);
8801 perf_event_ctx_unlock(event->group_leader, ctx);
8804 module_put(pmu->module);
8809 static struct pmu *perf_init_event(struct perf_event *event)
8811 struct pmu *pmu = NULL;
8815 idx = srcu_read_lock(&pmus_srcu);
8818 pmu = idr_find(&pmu_idr, event->attr.type);
8821 ret = perf_try_init_event(pmu, event);
8827 list_for_each_entry_rcu(pmu, &pmus, entry) {
8828 ret = perf_try_init_event(pmu, event);
8832 if (ret != -ENOENT) {
8837 pmu = ERR_PTR(-ENOENT);
8839 srcu_read_unlock(&pmus_srcu, idx);
8844 static void attach_sb_event(struct perf_event *event)
8846 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
8848 raw_spin_lock(&pel->lock);
8849 list_add_rcu(&event->sb_list, &pel->list);
8850 raw_spin_unlock(&pel->lock);
8854 * We keep a list of all !task (and therefore per-cpu) events
8855 * that need to receive side-band records.
8857 * This avoids having to scan all the various PMU per-cpu contexts
8860 static void account_pmu_sb_event(struct perf_event *event)
8862 if (is_sb_event(event))
8863 attach_sb_event(event);
8866 static void account_event_cpu(struct perf_event *event, int cpu)
8871 if (is_cgroup_event(event))
8872 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
8875 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
8876 static void account_freq_event_nohz(void)
8878 #ifdef CONFIG_NO_HZ_FULL
8879 /* Lock so we don't race with concurrent unaccount */
8880 spin_lock(&nr_freq_lock);
8881 if (atomic_inc_return(&nr_freq_events) == 1)
8882 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
8883 spin_unlock(&nr_freq_lock);
8887 static void account_freq_event(void)
8889 if (tick_nohz_full_enabled())
8890 account_freq_event_nohz();
8892 atomic_inc(&nr_freq_events);
8896 static void account_event(struct perf_event *event)
8903 if (event->attach_state & PERF_ATTACH_TASK)
8905 if (event->attr.mmap || event->attr.mmap_data)
8906 atomic_inc(&nr_mmap_events);
8907 if (event->attr.comm)
8908 atomic_inc(&nr_comm_events);
8909 if (event->attr.task)
8910 atomic_inc(&nr_task_events);
8911 if (event->attr.freq)
8912 account_freq_event();
8913 if (event->attr.context_switch) {
8914 atomic_inc(&nr_switch_events);
8917 if (has_branch_stack(event))
8919 if (is_cgroup_event(event))
8923 if (atomic_inc_not_zero(&perf_sched_count))
8926 mutex_lock(&perf_sched_mutex);
8927 if (!atomic_read(&perf_sched_count)) {
8928 static_branch_enable(&perf_sched_events);
8930 * Guarantee that all CPUs observe they key change and
8931 * call the perf scheduling hooks before proceeding to
8932 * install events that need them.
8934 synchronize_sched();
8937 * Now that we have waited for the sync_sched(), allow further
8938 * increments to by-pass the mutex.
8940 atomic_inc(&perf_sched_count);
8941 mutex_unlock(&perf_sched_mutex);
8945 account_event_cpu(event, event->cpu);
8947 account_pmu_sb_event(event);
8951 * Allocate and initialize a event structure
8953 static struct perf_event *
8954 perf_event_alloc(struct perf_event_attr *attr, int cpu,
8955 struct task_struct *task,
8956 struct perf_event *group_leader,
8957 struct perf_event *parent_event,
8958 perf_overflow_handler_t overflow_handler,
8959 void *context, int cgroup_fd)
8962 struct perf_event *event;
8963 struct hw_perf_event *hwc;
8966 if ((unsigned)cpu >= nr_cpu_ids) {
8967 if (!task || cpu != -1)
8968 return ERR_PTR(-EINVAL);
8971 event = kzalloc(sizeof(*event), GFP_KERNEL);
8973 return ERR_PTR(-ENOMEM);
8976 * Single events are their own group leaders, with an
8977 * empty sibling list:
8980 group_leader = event;
8982 mutex_init(&event->child_mutex);
8983 INIT_LIST_HEAD(&event->child_list);
8985 INIT_LIST_HEAD(&event->group_entry);
8986 INIT_LIST_HEAD(&event->event_entry);
8987 INIT_LIST_HEAD(&event->sibling_list);
8988 INIT_LIST_HEAD(&event->rb_entry);
8989 INIT_LIST_HEAD(&event->active_entry);
8990 INIT_LIST_HEAD(&event->addr_filters.list);
8991 INIT_HLIST_NODE(&event->hlist_entry);
8994 init_waitqueue_head(&event->waitq);
8995 init_irq_work(&event->pending, perf_pending_event);
8997 mutex_init(&event->mmap_mutex);
8998 raw_spin_lock_init(&event->addr_filters.lock);
9000 atomic_long_set(&event->refcount, 1);
9002 event->attr = *attr;
9003 event->group_leader = group_leader;
9007 event->parent = parent_event;
9009 event->ns = get_pid_ns(task_active_pid_ns(current));
9010 event->id = atomic64_inc_return(&perf_event_id);
9012 event->state = PERF_EVENT_STATE_INACTIVE;
9015 event->attach_state = PERF_ATTACH_TASK;
9017 * XXX pmu::event_init needs to know what task to account to
9018 * and we cannot use the ctx information because we need the
9019 * pmu before we get a ctx.
9021 event->hw.target = task;
9024 event->clock = &local_clock;
9026 event->clock = parent_event->clock;
9028 if (!overflow_handler && parent_event) {
9029 overflow_handler = parent_event->overflow_handler;
9030 context = parent_event->overflow_handler_context;
9033 if (overflow_handler) {
9034 event->overflow_handler = overflow_handler;
9035 event->overflow_handler_context = context;
9036 } else if (is_write_backward(event)){
9037 event->overflow_handler = perf_event_output_backward;
9038 event->overflow_handler_context = NULL;
9040 event->overflow_handler = perf_event_output_forward;
9041 event->overflow_handler_context = NULL;
9044 perf_event__state_init(event);
9049 hwc->sample_period = attr->sample_period;
9050 if (attr->freq && attr->sample_freq)
9051 hwc->sample_period = 1;
9052 hwc->last_period = hwc->sample_period;
9054 local64_set(&hwc->period_left, hwc->sample_period);
9057 * we currently do not support PERF_FORMAT_GROUP on inherited events
9059 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9062 if (!has_branch_stack(event))
9063 event->attr.branch_sample_type = 0;
9065 if (cgroup_fd != -1) {
9066 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9071 pmu = perf_init_event(event);
9074 else if (IS_ERR(pmu)) {
9079 err = exclusive_event_init(event);
9083 if (has_addr_filter(event)) {
9084 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9085 sizeof(unsigned long),
9087 if (!event->addr_filters_offs)
9090 /* force hw sync on the address filters */
9091 event->addr_filters_gen = 1;
9094 if (!event->parent) {
9095 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9096 err = get_callchain_buffers(attr->sample_max_stack);
9098 goto err_addr_filters;
9102 /* symmetric to unaccount_event() in _free_event() */
9103 account_event(event);
9108 kfree(event->addr_filters_offs);
9111 exclusive_event_destroy(event);
9115 event->destroy(event);
9116 module_put(pmu->module);
9118 if (is_cgroup_event(event))
9119 perf_detach_cgroup(event);
9121 put_pid_ns(event->ns);
9124 return ERR_PTR(err);
9127 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9128 struct perf_event_attr *attr)
9133 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9137 * zero the full structure, so that a short copy will be nice.
9139 memset(attr, 0, sizeof(*attr));
9141 ret = get_user(size, &uattr->size);
9145 if (size > PAGE_SIZE) /* silly large */
9148 if (!size) /* abi compat */
9149 size = PERF_ATTR_SIZE_VER0;
9151 if (size < PERF_ATTR_SIZE_VER0)
9155 * If we're handed a bigger struct than we know of,
9156 * ensure all the unknown bits are 0 - i.e. new
9157 * user-space does not rely on any kernel feature
9158 * extensions we dont know about yet.
9160 if (size > sizeof(*attr)) {
9161 unsigned char __user *addr;
9162 unsigned char __user *end;
9165 addr = (void __user *)uattr + sizeof(*attr);
9166 end = (void __user *)uattr + size;
9168 for (; addr < end; addr++) {
9169 ret = get_user(val, addr);
9175 size = sizeof(*attr);
9178 ret = copy_from_user(attr, uattr, size);
9182 if (attr->__reserved_1)
9185 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9188 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9191 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9192 u64 mask = attr->branch_sample_type;
9194 /* only using defined bits */
9195 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9198 /* at least one branch bit must be set */
9199 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9202 /* propagate priv level, when not set for branch */
9203 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9205 /* exclude_kernel checked on syscall entry */
9206 if (!attr->exclude_kernel)
9207 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9209 if (!attr->exclude_user)
9210 mask |= PERF_SAMPLE_BRANCH_USER;
9212 if (!attr->exclude_hv)
9213 mask |= PERF_SAMPLE_BRANCH_HV;
9215 * adjust user setting (for HW filter setup)
9217 attr->branch_sample_type = mask;
9219 /* privileged levels capture (kernel, hv): check permissions */
9220 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9221 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9225 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9226 ret = perf_reg_validate(attr->sample_regs_user);
9231 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9232 if (!arch_perf_have_user_stack_dump())
9236 * We have __u32 type for the size, but so far
9237 * we can only use __u16 as maximum due to the
9238 * __u16 sample size limit.
9240 if (attr->sample_stack_user >= USHRT_MAX)
9242 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9246 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9247 ret = perf_reg_validate(attr->sample_regs_intr);
9252 put_user(sizeof(*attr), &uattr->size);
9258 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9260 struct ring_buffer *rb = NULL;
9266 /* don't allow circular references */
9267 if (event == output_event)
9271 * Don't allow cross-cpu buffers
9273 if (output_event->cpu != event->cpu)
9277 * If its not a per-cpu rb, it must be the same task.
9279 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9283 * Mixing clocks in the same buffer is trouble you don't need.
9285 if (output_event->clock != event->clock)
9289 * Either writing ring buffer from beginning or from end.
9290 * Mixing is not allowed.
9292 if (is_write_backward(output_event) != is_write_backward(event))
9296 * If both events generate aux data, they must be on the same PMU
9298 if (has_aux(event) && has_aux(output_event) &&
9299 event->pmu != output_event->pmu)
9303 mutex_lock(&event->mmap_mutex);
9304 /* Can't redirect output if we've got an active mmap() */
9305 if (atomic_read(&event->mmap_count))
9309 /* get the rb we want to redirect to */
9310 rb = ring_buffer_get(output_event);
9315 ring_buffer_attach(event, rb);
9319 mutex_unlock(&event->mmap_mutex);
9325 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9331 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9334 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9336 bool nmi_safe = false;
9339 case CLOCK_MONOTONIC:
9340 event->clock = &ktime_get_mono_fast_ns;
9344 case CLOCK_MONOTONIC_RAW:
9345 event->clock = &ktime_get_raw_fast_ns;
9349 case CLOCK_REALTIME:
9350 event->clock = &ktime_get_real_ns;
9353 case CLOCK_BOOTTIME:
9354 event->clock = &ktime_get_boot_ns;
9358 event->clock = &ktime_get_tai_ns;
9365 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9372 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9374 * @attr_uptr: event_id type attributes for monitoring/sampling
9377 * @group_fd: group leader event fd
9379 SYSCALL_DEFINE5(perf_event_open,
9380 struct perf_event_attr __user *, attr_uptr,
9381 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9383 struct perf_event *group_leader = NULL, *output_event = NULL;
9384 struct perf_event *event, *sibling;
9385 struct perf_event_attr attr;
9386 struct perf_event_context *ctx, *uninitialized_var(gctx);
9387 struct file *event_file = NULL;
9388 struct fd group = {NULL, 0};
9389 struct task_struct *task = NULL;
9394 int f_flags = O_RDWR;
9397 /* for future expandability... */
9398 if (flags & ~PERF_FLAG_ALL)
9401 err = perf_copy_attr(attr_uptr, &attr);
9405 if (!attr.exclude_kernel) {
9406 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9411 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9414 if (attr.sample_period & (1ULL << 63))
9418 if (!attr.sample_max_stack)
9419 attr.sample_max_stack = sysctl_perf_event_max_stack;
9422 * In cgroup mode, the pid argument is used to pass the fd
9423 * opened to the cgroup directory in cgroupfs. The cpu argument
9424 * designates the cpu on which to monitor threads from that
9427 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9430 if (flags & PERF_FLAG_FD_CLOEXEC)
9431 f_flags |= O_CLOEXEC;
9433 event_fd = get_unused_fd_flags(f_flags);
9437 if (group_fd != -1) {
9438 err = perf_fget_light(group_fd, &group);
9441 group_leader = group.file->private_data;
9442 if (flags & PERF_FLAG_FD_OUTPUT)
9443 output_event = group_leader;
9444 if (flags & PERF_FLAG_FD_NO_GROUP)
9445 group_leader = NULL;
9448 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9449 task = find_lively_task_by_vpid(pid);
9451 err = PTR_ERR(task);
9456 if (task && group_leader &&
9457 group_leader->attr.inherit != attr.inherit) {
9465 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9470 * Reuse ptrace permission checks for now.
9472 * We must hold cred_guard_mutex across this and any potential
9473 * perf_install_in_context() call for this new event to
9474 * serialize against exec() altering our credentials (and the
9475 * perf_event_exit_task() that could imply).
9478 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9482 if (flags & PERF_FLAG_PID_CGROUP)
9485 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9486 NULL, NULL, cgroup_fd);
9487 if (IS_ERR(event)) {
9488 err = PTR_ERR(event);
9492 if (is_sampling_event(event)) {
9493 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9500 * Special case software events and allow them to be part of
9501 * any hardware group.
9505 if (attr.use_clockid) {
9506 err = perf_event_set_clock(event, attr.clockid);
9511 if (pmu->task_ctx_nr == perf_sw_context)
9512 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9515 (is_software_event(event) != is_software_event(group_leader))) {
9516 if (is_software_event(event)) {
9518 * If event and group_leader are not both a software
9519 * event, and event is, then group leader is not.
9521 * Allow the addition of software events to !software
9522 * groups, this is safe because software events never
9525 pmu = group_leader->pmu;
9526 } else if (is_software_event(group_leader) &&
9527 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9529 * In case the group is a pure software group, and we
9530 * try to add a hardware event, move the whole group to
9531 * the hardware context.
9538 * Get the target context (task or percpu):
9540 ctx = find_get_context(pmu, task, event);
9546 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9552 * Look up the group leader (we will attach this event to it):
9558 * Do not allow a recursive hierarchy (this new sibling
9559 * becoming part of another group-sibling):
9561 if (group_leader->group_leader != group_leader)
9564 /* All events in a group should have the same clock */
9565 if (group_leader->clock != event->clock)
9569 * Do not allow to attach to a group in a different
9570 * task or CPU context:
9574 * Make sure we're both on the same task, or both
9577 if (group_leader->ctx->task != ctx->task)
9581 * Make sure we're both events for the same CPU;
9582 * grouping events for different CPUs is broken; since
9583 * you can never concurrently schedule them anyhow.
9585 if (group_leader->cpu != event->cpu)
9588 if (group_leader->ctx != ctx)
9593 * Only a group leader can be exclusive or pinned
9595 if (attr.exclusive || attr.pinned)
9600 err = perf_event_set_output(event, output_event);
9605 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9607 if (IS_ERR(event_file)) {
9608 err = PTR_ERR(event_file);
9614 gctx = group_leader->ctx;
9615 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9616 if (gctx->task == TASK_TOMBSTONE) {
9621 mutex_lock(&ctx->mutex);
9624 if (ctx->task == TASK_TOMBSTONE) {
9629 if (!perf_event_validate_size(event)) {
9635 * Must be under the same ctx::mutex as perf_install_in_context(),
9636 * because we need to serialize with concurrent event creation.
9638 if (!exclusive_event_installable(event, ctx)) {
9639 /* exclusive and group stuff are assumed mutually exclusive */
9640 WARN_ON_ONCE(move_group);
9646 WARN_ON_ONCE(ctx->parent_ctx);
9649 * This is the point on no return; we cannot fail hereafter. This is
9650 * where we start modifying current state.
9655 * See perf_event_ctx_lock() for comments on the details
9656 * of swizzling perf_event::ctx.
9658 perf_remove_from_context(group_leader, 0);
9660 list_for_each_entry(sibling, &group_leader->sibling_list,
9662 perf_remove_from_context(sibling, 0);
9667 * Wait for everybody to stop referencing the events through
9668 * the old lists, before installing it on new lists.
9673 * Install the group siblings before the group leader.
9675 * Because a group leader will try and install the entire group
9676 * (through the sibling list, which is still in-tact), we can
9677 * end up with siblings installed in the wrong context.
9679 * By installing siblings first we NO-OP because they're not
9680 * reachable through the group lists.
9682 list_for_each_entry(sibling, &group_leader->sibling_list,
9684 perf_event__state_init(sibling);
9685 perf_install_in_context(ctx, sibling, sibling->cpu);
9690 * Removing from the context ends up with disabled
9691 * event. What we want here is event in the initial
9692 * startup state, ready to be add into new context.
9694 perf_event__state_init(group_leader);
9695 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9699 * Now that all events are installed in @ctx, nothing
9700 * references @gctx anymore, so drop the last reference we have
9707 * Precalculate sample_data sizes; do while holding ctx::mutex such
9708 * that we're serialized against further additions and before
9709 * perf_install_in_context() which is the point the event is active and
9710 * can use these values.
9712 perf_event__header_size(event);
9713 perf_event__id_header_size(event);
9715 event->owner = current;
9717 perf_install_in_context(ctx, event, event->cpu);
9718 perf_unpin_context(ctx);
9721 mutex_unlock(&gctx->mutex);
9722 mutex_unlock(&ctx->mutex);
9725 mutex_unlock(&task->signal->cred_guard_mutex);
9726 put_task_struct(task);
9731 mutex_lock(¤t->perf_event_mutex);
9732 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9733 mutex_unlock(¤t->perf_event_mutex);
9736 * Drop the reference on the group_event after placing the
9737 * new event on the sibling_list. This ensures destruction
9738 * of the group leader will find the pointer to itself in
9739 * perf_group_detach().
9742 fd_install(event_fd, event_file);
9747 mutex_unlock(&gctx->mutex);
9748 mutex_unlock(&ctx->mutex);
9752 perf_unpin_context(ctx);
9756 * If event_file is set, the fput() above will have called ->release()
9757 * and that will take care of freeing the event.
9763 mutex_unlock(&task->signal->cred_guard_mutex);
9768 put_task_struct(task);
9772 put_unused_fd(event_fd);
9777 * perf_event_create_kernel_counter
9779 * @attr: attributes of the counter to create
9780 * @cpu: cpu in which the counter is bound
9781 * @task: task to profile (NULL for percpu)
9784 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
9785 struct task_struct *task,
9786 perf_overflow_handler_t overflow_handler,
9789 struct perf_event_context *ctx;
9790 struct perf_event *event;
9794 * Get the target context (task or percpu):
9797 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9798 overflow_handler, context, -1);
9799 if (IS_ERR(event)) {
9800 err = PTR_ERR(event);
9804 /* Mark owner so we could distinguish it from user events. */
9805 event->owner = TASK_TOMBSTONE;
9807 ctx = find_get_context(event->pmu, task, event);
9813 WARN_ON_ONCE(ctx->parent_ctx);
9814 mutex_lock(&ctx->mutex);
9815 if (ctx->task == TASK_TOMBSTONE) {
9820 if (!exclusive_event_installable(event, ctx)) {
9825 perf_install_in_context(ctx, event, cpu);
9826 perf_unpin_context(ctx);
9827 mutex_unlock(&ctx->mutex);
9832 mutex_unlock(&ctx->mutex);
9833 perf_unpin_context(ctx);
9838 return ERR_PTR(err);
9840 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
9842 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
9844 struct perf_event_context *src_ctx;
9845 struct perf_event_context *dst_ctx;
9846 struct perf_event *event, *tmp;
9849 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
9850 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
9853 * See perf_event_ctx_lock() for comments on the details
9854 * of swizzling perf_event::ctx.
9856 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
9857 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
9859 perf_remove_from_context(event, 0);
9860 unaccount_event_cpu(event, src_cpu);
9862 list_add(&event->migrate_entry, &events);
9866 * Wait for the events to quiesce before re-instating them.
9871 * Re-instate events in 2 passes.
9873 * Skip over group leaders and only install siblings on this first
9874 * pass, siblings will not get enabled without a leader, however a
9875 * leader will enable its siblings, even if those are still on the old
9878 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9879 if (event->group_leader == event)
9882 list_del(&event->migrate_entry);
9883 if (event->state >= PERF_EVENT_STATE_OFF)
9884 event->state = PERF_EVENT_STATE_INACTIVE;
9885 account_event_cpu(event, dst_cpu);
9886 perf_install_in_context(dst_ctx, event, dst_cpu);
9891 * Once all the siblings are setup properly, install the group leaders
9894 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
9895 list_del(&event->migrate_entry);
9896 if (event->state >= PERF_EVENT_STATE_OFF)
9897 event->state = PERF_EVENT_STATE_INACTIVE;
9898 account_event_cpu(event, dst_cpu);
9899 perf_install_in_context(dst_ctx, event, dst_cpu);
9902 mutex_unlock(&dst_ctx->mutex);
9903 mutex_unlock(&src_ctx->mutex);
9905 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
9907 static void sync_child_event(struct perf_event *child_event,
9908 struct task_struct *child)
9910 struct perf_event *parent_event = child_event->parent;
9913 if (child_event->attr.inherit_stat)
9914 perf_event_read_event(child_event, child);
9916 child_val = perf_event_count(child_event);
9919 * Add back the child's count to the parent's count:
9921 atomic64_add(child_val, &parent_event->child_count);
9922 atomic64_add(child_event->total_time_enabled,
9923 &parent_event->child_total_time_enabled);
9924 atomic64_add(child_event->total_time_running,
9925 &parent_event->child_total_time_running);
9929 perf_event_exit_event(struct perf_event *child_event,
9930 struct perf_event_context *child_ctx,
9931 struct task_struct *child)
9933 struct perf_event *parent_event = child_event->parent;
9936 * Do not destroy the 'original' grouping; because of the context
9937 * switch optimization the original events could've ended up in a
9938 * random child task.
9940 * If we were to destroy the original group, all group related
9941 * operations would cease to function properly after this random
9944 * Do destroy all inherited groups, we don't care about those
9945 * and being thorough is better.
9947 raw_spin_lock_irq(&child_ctx->lock);
9948 WARN_ON_ONCE(child_ctx->is_active);
9951 perf_group_detach(child_event);
9952 list_del_event(child_event, child_ctx);
9953 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
9954 raw_spin_unlock_irq(&child_ctx->lock);
9957 * Parent events are governed by their filedesc, retain them.
9959 if (!parent_event) {
9960 perf_event_wakeup(child_event);
9964 * Child events can be cleaned up.
9967 sync_child_event(child_event, child);
9970 * Remove this event from the parent's list
9972 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9973 mutex_lock(&parent_event->child_mutex);
9974 list_del_init(&child_event->child_list);
9975 mutex_unlock(&parent_event->child_mutex);
9978 * Kick perf_poll() for is_event_hup().
9980 perf_event_wakeup(parent_event);
9981 free_event(child_event);
9982 put_event(parent_event);
9985 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
9987 struct perf_event_context *child_ctx, *clone_ctx = NULL;
9988 struct perf_event *child_event, *next;
9990 WARN_ON_ONCE(child != current);
9992 child_ctx = perf_pin_task_context(child, ctxn);
9997 * In order to reduce the amount of tricky in ctx tear-down, we hold
9998 * ctx::mutex over the entire thing. This serializes against almost
9999 * everything that wants to access the ctx.
10001 * The exception is sys_perf_event_open() /
10002 * perf_event_create_kernel_count() which does find_get_context()
10003 * without ctx::mutex (it cannot because of the move_group double mutex
10004 * lock thing). See the comments in perf_install_in_context().
10006 mutex_lock(&child_ctx->mutex);
10009 * In a single ctx::lock section, de-schedule the events and detach the
10010 * context from the task such that we cannot ever get it scheduled back
10013 raw_spin_lock_irq(&child_ctx->lock);
10014 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
10017 * Now that the context is inactive, destroy the task <-> ctx relation
10018 * and mark the context dead.
10020 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10021 put_ctx(child_ctx); /* cannot be last */
10022 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10023 put_task_struct(current); /* cannot be last */
10025 clone_ctx = unclone_ctx(child_ctx);
10026 raw_spin_unlock_irq(&child_ctx->lock);
10029 put_ctx(clone_ctx);
10032 * Report the task dead after unscheduling the events so that we
10033 * won't get any samples after PERF_RECORD_EXIT. We can however still
10034 * get a few PERF_RECORD_READ events.
10036 perf_event_task(child, child_ctx, 0);
10038 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10039 perf_event_exit_event(child_event, child_ctx, child);
10041 mutex_unlock(&child_ctx->mutex);
10043 put_ctx(child_ctx);
10047 * When a child task exits, feed back event values to parent events.
10049 * Can be called with cred_guard_mutex held when called from
10050 * install_exec_creds().
10052 void perf_event_exit_task(struct task_struct *child)
10054 struct perf_event *event, *tmp;
10057 mutex_lock(&child->perf_event_mutex);
10058 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10060 list_del_init(&event->owner_entry);
10063 * Ensure the list deletion is visible before we clear
10064 * the owner, closes a race against perf_release() where
10065 * we need to serialize on the owner->perf_event_mutex.
10067 smp_store_release(&event->owner, NULL);
10069 mutex_unlock(&child->perf_event_mutex);
10071 for_each_task_context_nr(ctxn)
10072 perf_event_exit_task_context(child, ctxn);
10075 * The perf_event_exit_task_context calls perf_event_task
10076 * with child's task_ctx, which generates EXIT events for
10077 * child contexts and sets child->perf_event_ctxp[] to NULL.
10078 * At this point we need to send EXIT events to cpu contexts.
10080 perf_event_task(child, NULL, 0);
10083 static void perf_free_event(struct perf_event *event,
10084 struct perf_event_context *ctx)
10086 struct perf_event *parent = event->parent;
10088 if (WARN_ON_ONCE(!parent))
10091 mutex_lock(&parent->child_mutex);
10092 list_del_init(&event->child_list);
10093 mutex_unlock(&parent->child_mutex);
10097 raw_spin_lock_irq(&ctx->lock);
10098 perf_group_detach(event);
10099 list_del_event(event, ctx);
10100 raw_spin_unlock_irq(&ctx->lock);
10105 * Free an unexposed, unused context as created by inheritance by
10106 * perf_event_init_task below, used by fork() in case of fail.
10108 * Not all locks are strictly required, but take them anyway to be nice and
10109 * help out with the lockdep assertions.
10111 void perf_event_free_task(struct task_struct *task)
10113 struct perf_event_context *ctx;
10114 struct perf_event *event, *tmp;
10117 for_each_task_context_nr(ctxn) {
10118 ctx = task->perf_event_ctxp[ctxn];
10122 mutex_lock(&ctx->mutex);
10124 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10126 perf_free_event(event, ctx);
10128 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10130 perf_free_event(event, ctx);
10132 if (!list_empty(&ctx->pinned_groups) ||
10133 !list_empty(&ctx->flexible_groups))
10136 mutex_unlock(&ctx->mutex);
10142 void perf_event_delayed_put(struct task_struct *task)
10146 for_each_task_context_nr(ctxn)
10147 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10150 struct file *perf_event_get(unsigned int fd)
10154 file = fget_raw(fd);
10156 return ERR_PTR(-EBADF);
10158 if (file->f_op != &perf_fops) {
10160 return ERR_PTR(-EBADF);
10166 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10169 return ERR_PTR(-EINVAL);
10171 return &event->attr;
10175 * inherit a event from parent task to child task:
10177 static struct perf_event *
10178 inherit_event(struct perf_event *parent_event,
10179 struct task_struct *parent,
10180 struct perf_event_context *parent_ctx,
10181 struct task_struct *child,
10182 struct perf_event *group_leader,
10183 struct perf_event_context *child_ctx)
10185 enum perf_event_active_state parent_state = parent_event->state;
10186 struct perf_event *child_event;
10187 unsigned long flags;
10190 * Instead of creating recursive hierarchies of events,
10191 * we link inherited events back to the original parent,
10192 * which has a filp for sure, which we use as the reference
10195 if (parent_event->parent)
10196 parent_event = parent_event->parent;
10198 child_event = perf_event_alloc(&parent_event->attr,
10201 group_leader, parent_event,
10203 if (IS_ERR(child_event))
10204 return child_event;
10207 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10208 * must be under the same lock in order to serialize against
10209 * perf_event_release_kernel(), such that either we must observe
10210 * is_orphaned_event() or they will observe us on the child_list.
10212 mutex_lock(&parent_event->child_mutex);
10213 if (is_orphaned_event(parent_event) ||
10214 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10215 mutex_unlock(&parent_event->child_mutex);
10216 free_event(child_event);
10220 get_ctx(child_ctx);
10223 * Make the child state follow the state of the parent event,
10224 * not its attr.disabled bit. We hold the parent's mutex,
10225 * so we won't race with perf_event_{en, dis}able_family.
10227 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10228 child_event->state = PERF_EVENT_STATE_INACTIVE;
10230 child_event->state = PERF_EVENT_STATE_OFF;
10232 if (parent_event->attr.freq) {
10233 u64 sample_period = parent_event->hw.sample_period;
10234 struct hw_perf_event *hwc = &child_event->hw;
10236 hwc->sample_period = sample_period;
10237 hwc->last_period = sample_period;
10239 local64_set(&hwc->period_left, sample_period);
10242 child_event->ctx = child_ctx;
10243 child_event->overflow_handler = parent_event->overflow_handler;
10244 child_event->overflow_handler_context
10245 = parent_event->overflow_handler_context;
10248 * Precalculate sample_data sizes
10250 perf_event__header_size(child_event);
10251 perf_event__id_header_size(child_event);
10254 * Link it up in the child's context:
10256 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10257 add_event_to_ctx(child_event, child_ctx);
10258 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10261 * Link this into the parent event's child list
10263 list_add_tail(&child_event->child_list, &parent_event->child_list);
10264 mutex_unlock(&parent_event->child_mutex);
10266 return child_event;
10269 static int inherit_group(struct perf_event *parent_event,
10270 struct task_struct *parent,
10271 struct perf_event_context *parent_ctx,
10272 struct task_struct *child,
10273 struct perf_event_context *child_ctx)
10275 struct perf_event *leader;
10276 struct perf_event *sub;
10277 struct perf_event *child_ctr;
10279 leader = inherit_event(parent_event, parent, parent_ctx,
10280 child, NULL, child_ctx);
10281 if (IS_ERR(leader))
10282 return PTR_ERR(leader);
10283 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10284 child_ctr = inherit_event(sub, parent, parent_ctx,
10285 child, leader, child_ctx);
10286 if (IS_ERR(child_ctr))
10287 return PTR_ERR(child_ctr);
10293 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10294 struct perf_event_context *parent_ctx,
10295 struct task_struct *child, int ctxn,
10296 int *inherited_all)
10299 struct perf_event_context *child_ctx;
10301 if (!event->attr.inherit) {
10302 *inherited_all = 0;
10306 child_ctx = child->perf_event_ctxp[ctxn];
10309 * This is executed from the parent task context, so
10310 * inherit events that have been marked for cloning.
10311 * First allocate and initialize a context for the
10315 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10319 child->perf_event_ctxp[ctxn] = child_ctx;
10322 ret = inherit_group(event, parent, parent_ctx,
10326 *inherited_all = 0;
10332 * Initialize the perf_event context in task_struct
10334 static int perf_event_init_context(struct task_struct *child, int ctxn)
10336 struct perf_event_context *child_ctx, *parent_ctx;
10337 struct perf_event_context *cloned_ctx;
10338 struct perf_event *event;
10339 struct task_struct *parent = current;
10340 int inherited_all = 1;
10341 unsigned long flags;
10344 if (likely(!parent->perf_event_ctxp[ctxn]))
10348 * If the parent's context is a clone, pin it so it won't get
10349 * swapped under us.
10351 parent_ctx = perf_pin_task_context(parent, ctxn);
10356 * No need to check if parent_ctx != NULL here; since we saw
10357 * it non-NULL earlier, the only reason for it to become NULL
10358 * is if we exit, and since we're currently in the middle of
10359 * a fork we can't be exiting at the same time.
10363 * Lock the parent list. No need to lock the child - not PID
10364 * hashed yet and not running, so nobody can access it.
10366 mutex_lock(&parent_ctx->mutex);
10369 * We dont have to disable NMIs - we are only looking at
10370 * the list, not manipulating it:
10372 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10373 ret = inherit_task_group(event, parent, parent_ctx,
10374 child, ctxn, &inherited_all);
10380 * We can't hold ctx->lock when iterating the ->flexible_group list due
10381 * to allocations, but we need to prevent rotation because
10382 * rotate_ctx() will change the list from interrupt context.
10384 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10385 parent_ctx->rotate_disable = 1;
10386 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10388 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10389 ret = inherit_task_group(event, parent, parent_ctx,
10390 child, ctxn, &inherited_all);
10395 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10396 parent_ctx->rotate_disable = 0;
10398 child_ctx = child->perf_event_ctxp[ctxn];
10400 if (child_ctx && inherited_all) {
10402 * Mark the child context as a clone of the parent
10403 * context, or of whatever the parent is a clone of.
10405 * Note that if the parent is a clone, the holding of
10406 * parent_ctx->lock avoids it from being uncloned.
10408 cloned_ctx = parent_ctx->parent_ctx;
10410 child_ctx->parent_ctx = cloned_ctx;
10411 child_ctx->parent_gen = parent_ctx->parent_gen;
10413 child_ctx->parent_ctx = parent_ctx;
10414 child_ctx->parent_gen = parent_ctx->generation;
10416 get_ctx(child_ctx->parent_ctx);
10419 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10420 mutex_unlock(&parent_ctx->mutex);
10422 perf_unpin_context(parent_ctx);
10423 put_ctx(parent_ctx);
10429 * Initialize the perf_event context in task_struct
10431 int perf_event_init_task(struct task_struct *child)
10435 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10436 mutex_init(&child->perf_event_mutex);
10437 INIT_LIST_HEAD(&child->perf_event_list);
10439 for_each_task_context_nr(ctxn) {
10440 ret = perf_event_init_context(child, ctxn);
10442 perf_event_free_task(child);
10450 static void __init perf_event_init_all_cpus(void)
10452 struct swevent_htable *swhash;
10455 for_each_possible_cpu(cpu) {
10456 swhash = &per_cpu(swevent_htable, cpu);
10457 mutex_init(&swhash->hlist_mutex);
10458 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10460 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10461 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10463 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10467 int perf_event_init_cpu(unsigned int cpu)
10469 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10471 mutex_lock(&swhash->hlist_mutex);
10472 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10473 struct swevent_hlist *hlist;
10475 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10477 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10479 mutex_unlock(&swhash->hlist_mutex);
10483 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10484 static void __perf_event_exit_context(void *__info)
10486 struct perf_event_context *ctx = __info;
10487 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10488 struct perf_event *event;
10490 raw_spin_lock(&ctx->lock);
10491 list_for_each_entry(event, &ctx->event_list, event_entry)
10492 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10493 raw_spin_unlock(&ctx->lock);
10496 static void perf_event_exit_cpu_context(int cpu)
10498 struct perf_event_context *ctx;
10502 idx = srcu_read_lock(&pmus_srcu);
10503 list_for_each_entry_rcu(pmu, &pmus, entry) {
10504 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10506 mutex_lock(&ctx->mutex);
10507 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10508 mutex_unlock(&ctx->mutex);
10510 srcu_read_unlock(&pmus_srcu, idx);
10514 static void perf_event_exit_cpu_context(int cpu) { }
10518 int perf_event_exit_cpu(unsigned int cpu)
10520 perf_event_exit_cpu_context(cpu);
10525 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10529 for_each_online_cpu(cpu)
10530 perf_event_exit_cpu(cpu);
10536 * Run the perf reboot notifier at the very last possible moment so that
10537 * the generic watchdog code runs as long as possible.
10539 static struct notifier_block perf_reboot_notifier = {
10540 .notifier_call = perf_reboot,
10541 .priority = INT_MIN,
10544 void __init perf_event_init(void)
10548 idr_init(&pmu_idr);
10550 perf_event_init_all_cpus();
10551 init_srcu_struct(&pmus_srcu);
10552 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10553 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10554 perf_pmu_register(&perf_task_clock, NULL, -1);
10555 perf_tp_register();
10556 perf_event_init_cpu(smp_processor_id());
10557 register_reboot_notifier(&perf_reboot_notifier);
10559 ret = init_hw_breakpoint();
10560 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10563 * Build time assertion that we keep the data_head at the intended
10564 * location. IOW, validation we got the __reserved[] size right.
10566 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10570 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10573 struct perf_pmu_events_attr *pmu_attr =
10574 container_of(attr, struct perf_pmu_events_attr, attr);
10576 if (pmu_attr->event_str)
10577 return sprintf(page, "%s\n", pmu_attr->event_str);
10581 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10583 static int __init perf_event_sysfs_init(void)
10588 mutex_lock(&pmus_lock);
10590 ret = bus_register(&pmu_bus);
10594 list_for_each_entry(pmu, &pmus, entry) {
10595 if (!pmu->name || pmu->type < 0)
10598 ret = pmu_dev_alloc(pmu);
10599 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10601 pmu_bus_running = 1;
10605 mutex_unlock(&pmus_lock);
10609 device_initcall(perf_event_sysfs_init);
10611 #ifdef CONFIG_CGROUP_PERF
10612 static struct cgroup_subsys_state *
10613 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10615 struct perf_cgroup *jc;
10617 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10619 return ERR_PTR(-ENOMEM);
10621 jc->info = alloc_percpu(struct perf_cgroup_info);
10624 return ERR_PTR(-ENOMEM);
10630 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10632 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10634 free_percpu(jc->info);
10638 static int __perf_cgroup_move(void *info)
10640 struct task_struct *task = info;
10642 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10647 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10649 struct task_struct *task;
10650 struct cgroup_subsys_state *css;
10652 cgroup_taskset_for_each(task, css, tset)
10653 task_function_call(task, __perf_cgroup_move, task);
10656 struct cgroup_subsys perf_event_cgrp_subsys = {
10657 .css_alloc = perf_cgroup_css_alloc,
10658 .css_free = perf_cgroup_css_free,
10659 .attach = perf_cgroup_attach,
10661 #endif /* CONFIG_CGROUP_PERF */