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);
907 * cpuctx->cgrp is NULL until a cgroup event is sched in or
908 * ctx->nr_cgroup == 0 .
910 if (add && perf_cgroup_from_task(current, ctx) == event->cgrp)
911 cpuctx->cgrp = event->cgrp;
916 #else /* !CONFIG_CGROUP_PERF */
919 perf_cgroup_match(struct perf_event *event)
924 static inline void perf_detach_cgroup(struct perf_event *event)
927 static inline int is_cgroup_event(struct perf_event *event)
932 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
937 static inline void update_cgrp_time_from_event(struct perf_event *event)
941 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
945 static inline void perf_cgroup_sched_out(struct task_struct *task,
946 struct task_struct *next)
950 static inline void perf_cgroup_sched_in(struct task_struct *prev,
951 struct task_struct *task)
955 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
956 struct perf_event_attr *attr,
957 struct perf_event *group_leader)
963 perf_cgroup_set_timestamp(struct task_struct *task,
964 struct perf_event_context *ctx)
969 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
974 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
978 static inline u64 perf_cgroup_event_time(struct perf_event *event)
984 perf_cgroup_defer_enabled(struct perf_event *event)
989 perf_cgroup_mark_enabled(struct perf_event *event,
990 struct perf_event_context *ctx)
995 list_update_cgroup_event(struct perf_event *event,
996 struct perf_event_context *ctx, bool add)
1003 * set default to be dependent on timer tick just
1004 * like original code
1006 #define PERF_CPU_HRTIMER (1000 / HZ)
1008 * function must be called with interrupts disbled
1010 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1012 struct perf_cpu_context *cpuctx;
1015 WARN_ON(!irqs_disabled());
1017 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1018 rotations = perf_rotate_context(cpuctx);
1020 raw_spin_lock(&cpuctx->hrtimer_lock);
1022 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1024 cpuctx->hrtimer_active = 0;
1025 raw_spin_unlock(&cpuctx->hrtimer_lock);
1027 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1030 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1032 struct hrtimer *timer = &cpuctx->hrtimer;
1033 struct pmu *pmu = cpuctx->ctx.pmu;
1036 /* no multiplexing needed for SW PMU */
1037 if (pmu->task_ctx_nr == perf_sw_context)
1041 * check default is sane, if not set then force to
1042 * default interval (1/tick)
1044 interval = pmu->hrtimer_interval_ms;
1046 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1048 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1050 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1051 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1052 timer->function = perf_mux_hrtimer_handler;
1055 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1057 struct hrtimer *timer = &cpuctx->hrtimer;
1058 struct pmu *pmu = cpuctx->ctx.pmu;
1059 unsigned long flags;
1061 /* not for SW PMU */
1062 if (pmu->task_ctx_nr == perf_sw_context)
1065 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1066 if (!cpuctx->hrtimer_active) {
1067 cpuctx->hrtimer_active = 1;
1068 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1069 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1071 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1076 void perf_pmu_disable(struct pmu *pmu)
1078 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1080 pmu->pmu_disable(pmu);
1083 void perf_pmu_enable(struct pmu *pmu)
1085 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1087 pmu->pmu_enable(pmu);
1090 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1093 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1094 * perf_event_task_tick() are fully serialized because they're strictly cpu
1095 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1096 * disabled, while perf_event_task_tick is called from IRQ context.
1098 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1100 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1102 WARN_ON(!irqs_disabled());
1104 WARN_ON(!list_empty(&ctx->active_ctx_list));
1106 list_add(&ctx->active_ctx_list, head);
1109 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1111 WARN_ON(!irqs_disabled());
1113 WARN_ON(list_empty(&ctx->active_ctx_list));
1115 list_del_init(&ctx->active_ctx_list);
1118 static void get_ctx(struct perf_event_context *ctx)
1120 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1123 static void free_ctx(struct rcu_head *head)
1125 struct perf_event_context *ctx;
1127 ctx = container_of(head, struct perf_event_context, rcu_head);
1128 kfree(ctx->task_ctx_data);
1132 static void put_ctx(struct perf_event_context *ctx)
1134 if (atomic_dec_and_test(&ctx->refcount)) {
1135 if (ctx->parent_ctx)
1136 put_ctx(ctx->parent_ctx);
1137 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1138 put_task_struct(ctx->task);
1139 call_rcu(&ctx->rcu_head, free_ctx);
1144 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1145 * perf_pmu_migrate_context() we need some magic.
1147 * Those places that change perf_event::ctx will hold both
1148 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1150 * Lock ordering is by mutex address. There are two other sites where
1151 * perf_event_context::mutex nests and those are:
1153 * - perf_event_exit_task_context() [ child , 0 ]
1154 * perf_event_exit_event()
1155 * put_event() [ parent, 1 ]
1157 * - perf_event_init_context() [ parent, 0 ]
1158 * inherit_task_group()
1161 * perf_event_alloc()
1163 * perf_try_init_event() [ child , 1 ]
1165 * While it appears there is an obvious deadlock here -- the parent and child
1166 * nesting levels are inverted between the two. This is in fact safe because
1167 * life-time rules separate them. That is an exiting task cannot fork, and a
1168 * spawning task cannot (yet) exit.
1170 * But remember that that these are parent<->child context relations, and
1171 * migration does not affect children, therefore these two orderings should not
1174 * The change in perf_event::ctx does not affect children (as claimed above)
1175 * because the sys_perf_event_open() case will install a new event and break
1176 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1177 * concerned with cpuctx and that doesn't have children.
1179 * The places that change perf_event::ctx will issue:
1181 * perf_remove_from_context();
1182 * synchronize_rcu();
1183 * perf_install_in_context();
1185 * to affect the change. The remove_from_context() + synchronize_rcu() should
1186 * quiesce the event, after which we can install it in the new location. This
1187 * means that only external vectors (perf_fops, prctl) can perturb the event
1188 * while in transit. Therefore all such accessors should also acquire
1189 * perf_event_context::mutex to serialize against this.
1191 * However; because event->ctx can change while we're waiting to acquire
1192 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1197 * task_struct::perf_event_mutex
1198 * perf_event_context::mutex
1199 * perf_event::child_mutex;
1200 * perf_event_context::lock
1201 * perf_event::mmap_mutex
1204 static struct perf_event_context *
1205 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1207 struct perf_event_context *ctx;
1211 ctx = ACCESS_ONCE(event->ctx);
1212 if (!atomic_inc_not_zero(&ctx->refcount)) {
1218 mutex_lock_nested(&ctx->mutex, nesting);
1219 if (event->ctx != ctx) {
1220 mutex_unlock(&ctx->mutex);
1228 static inline struct perf_event_context *
1229 perf_event_ctx_lock(struct perf_event *event)
1231 return perf_event_ctx_lock_nested(event, 0);
1234 static void perf_event_ctx_unlock(struct perf_event *event,
1235 struct perf_event_context *ctx)
1237 mutex_unlock(&ctx->mutex);
1242 * This must be done under the ctx->lock, such as to serialize against
1243 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1244 * calling scheduler related locks and ctx->lock nests inside those.
1246 static __must_check struct perf_event_context *
1247 unclone_ctx(struct perf_event_context *ctx)
1249 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1251 lockdep_assert_held(&ctx->lock);
1254 ctx->parent_ctx = NULL;
1260 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1263 * only top level events have the pid namespace they were created in
1266 event = event->parent;
1268 return task_tgid_nr_ns(p, event->ns);
1271 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1274 * only top level events have the pid namespace they were created in
1277 event = event->parent;
1279 return task_pid_nr_ns(p, event->ns);
1283 * If we inherit events we want to return the parent event id
1286 static u64 primary_event_id(struct perf_event *event)
1291 id = event->parent->id;
1297 * Get the perf_event_context for a task and lock it.
1299 * This has to cope with with the fact that until it is locked,
1300 * the context could get moved to another task.
1302 static struct perf_event_context *
1303 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1305 struct perf_event_context *ctx;
1309 * One of the few rules of preemptible RCU is that one cannot do
1310 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1311 * part of the read side critical section was irqs-enabled -- see
1312 * rcu_read_unlock_special().
1314 * Since ctx->lock nests under rq->lock we must ensure the entire read
1315 * side critical section has interrupts disabled.
1317 local_irq_save(*flags);
1319 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1322 * If this context is a clone of another, it might
1323 * get swapped for another underneath us by
1324 * perf_event_task_sched_out, though the
1325 * rcu_read_lock() protects us from any context
1326 * getting freed. Lock the context and check if it
1327 * got swapped before we could get the lock, and retry
1328 * if so. If we locked the right context, then it
1329 * can't get swapped on us any more.
1331 raw_spin_lock(&ctx->lock);
1332 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1333 raw_spin_unlock(&ctx->lock);
1335 local_irq_restore(*flags);
1339 if (ctx->task == TASK_TOMBSTONE ||
1340 !atomic_inc_not_zero(&ctx->refcount)) {
1341 raw_spin_unlock(&ctx->lock);
1344 WARN_ON_ONCE(ctx->task != task);
1349 local_irq_restore(*flags);
1354 * Get the context for a task and increment its pin_count so it
1355 * can't get swapped to another task. This also increments its
1356 * reference count so that the context can't get freed.
1358 static struct perf_event_context *
1359 perf_pin_task_context(struct task_struct *task, int ctxn)
1361 struct perf_event_context *ctx;
1362 unsigned long flags;
1364 ctx = perf_lock_task_context(task, ctxn, &flags);
1367 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1372 static void perf_unpin_context(struct perf_event_context *ctx)
1374 unsigned long flags;
1376 raw_spin_lock_irqsave(&ctx->lock, flags);
1378 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1382 * Update the record of the current time in a context.
1384 static void update_context_time(struct perf_event_context *ctx)
1386 u64 now = perf_clock();
1388 ctx->time += now - ctx->timestamp;
1389 ctx->timestamp = now;
1392 static u64 perf_event_time(struct perf_event *event)
1394 struct perf_event_context *ctx = event->ctx;
1396 if (is_cgroup_event(event))
1397 return perf_cgroup_event_time(event);
1399 return ctx ? ctx->time : 0;
1403 * Update the total_time_enabled and total_time_running fields for a event.
1405 static void update_event_times(struct perf_event *event)
1407 struct perf_event_context *ctx = event->ctx;
1410 lockdep_assert_held(&ctx->lock);
1412 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1413 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1417 * in cgroup mode, time_enabled represents
1418 * the time the event was enabled AND active
1419 * tasks were in the monitored cgroup. This is
1420 * independent of the activity of the context as
1421 * there may be a mix of cgroup and non-cgroup events.
1423 * That is why we treat cgroup events differently
1426 if (is_cgroup_event(event))
1427 run_end = perf_cgroup_event_time(event);
1428 else if (ctx->is_active)
1429 run_end = ctx->time;
1431 run_end = event->tstamp_stopped;
1433 event->total_time_enabled = run_end - event->tstamp_enabled;
1435 if (event->state == PERF_EVENT_STATE_INACTIVE)
1436 run_end = event->tstamp_stopped;
1438 run_end = perf_event_time(event);
1440 event->total_time_running = run_end - event->tstamp_running;
1445 * Update total_time_enabled and total_time_running for all events in a group.
1447 static void update_group_times(struct perf_event *leader)
1449 struct perf_event *event;
1451 update_event_times(leader);
1452 list_for_each_entry(event, &leader->sibling_list, group_entry)
1453 update_event_times(event);
1456 static struct list_head *
1457 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1459 if (event->attr.pinned)
1460 return &ctx->pinned_groups;
1462 return &ctx->flexible_groups;
1466 * Add a event from the lists for its context.
1467 * Must be called with ctx->mutex and ctx->lock held.
1470 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1472 lockdep_assert_held(&ctx->lock);
1474 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1475 event->attach_state |= PERF_ATTACH_CONTEXT;
1478 * If we're a stand alone event or group leader, we go to the context
1479 * list, group events are kept attached to the group so that
1480 * perf_group_detach can, at all times, locate all siblings.
1482 if (event->group_leader == event) {
1483 struct list_head *list;
1485 event->group_caps = event->event_caps;
1487 list = ctx_group_list(event, ctx);
1488 list_add_tail(&event->group_entry, list);
1491 list_update_cgroup_event(event, ctx, true);
1493 list_add_rcu(&event->event_entry, &ctx->event_list);
1495 if (event->attr.inherit_stat)
1502 * Initialize event state based on the perf_event_attr::disabled.
1504 static inline void perf_event__state_init(struct perf_event *event)
1506 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1507 PERF_EVENT_STATE_INACTIVE;
1510 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1512 int entry = sizeof(u64); /* value */
1516 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1517 size += sizeof(u64);
1519 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1520 size += sizeof(u64);
1522 if (event->attr.read_format & PERF_FORMAT_ID)
1523 entry += sizeof(u64);
1525 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1527 size += sizeof(u64);
1531 event->read_size = size;
1534 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1536 struct perf_sample_data *data;
1539 if (sample_type & PERF_SAMPLE_IP)
1540 size += sizeof(data->ip);
1542 if (sample_type & PERF_SAMPLE_ADDR)
1543 size += sizeof(data->addr);
1545 if (sample_type & PERF_SAMPLE_PERIOD)
1546 size += sizeof(data->period);
1548 if (sample_type & PERF_SAMPLE_WEIGHT)
1549 size += sizeof(data->weight);
1551 if (sample_type & PERF_SAMPLE_READ)
1552 size += event->read_size;
1554 if (sample_type & PERF_SAMPLE_DATA_SRC)
1555 size += sizeof(data->data_src.val);
1557 if (sample_type & PERF_SAMPLE_TRANSACTION)
1558 size += sizeof(data->txn);
1560 event->header_size = size;
1564 * Called at perf_event creation and when events are attached/detached from a
1567 static void perf_event__header_size(struct perf_event *event)
1569 __perf_event_read_size(event,
1570 event->group_leader->nr_siblings);
1571 __perf_event_header_size(event, event->attr.sample_type);
1574 static void perf_event__id_header_size(struct perf_event *event)
1576 struct perf_sample_data *data;
1577 u64 sample_type = event->attr.sample_type;
1580 if (sample_type & PERF_SAMPLE_TID)
1581 size += sizeof(data->tid_entry);
1583 if (sample_type & PERF_SAMPLE_TIME)
1584 size += sizeof(data->time);
1586 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1587 size += sizeof(data->id);
1589 if (sample_type & PERF_SAMPLE_ID)
1590 size += sizeof(data->id);
1592 if (sample_type & PERF_SAMPLE_STREAM_ID)
1593 size += sizeof(data->stream_id);
1595 if (sample_type & PERF_SAMPLE_CPU)
1596 size += sizeof(data->cpu_entry);
1598 event->id_header_size = size;
1601 static bool perf_event_validate_size(struct perf_event *event)
1604 * The values computed here will be over-written when we actually
1607 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1608 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1609 perf_event__id_header_size(event);
1612 * Sum the lot; should not exceed the 64k limit we have on records.
1613 * Conservative limit to allow for callchains and other variable fields.
1615 if (event->read_size + event->header_size +
1616 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1622 static void perf_group_attach(struct perf_event *event)
1624 struct perf_event *group_leader = event->group_leader, *pos;
1626 lockdep_assert_held(&event->ctx->lock);
1629 * We can have double attach due to group movement in perf_event_open.
1631 if (event->attach_state & PERF_ATTACH_GROUP)
1634 event->attach_state |= PERF_ATTACH_GROUP;
1636 if (group_leader == event)
1639 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1641 group_leader->group_caps &= event->event_caps;
1643 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1644 group_leader->nr_siblings++;
1646 perf_event__header_size(group_leader);
1648 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1649 perf_event__header_size(pos);
1653 * Remove a event from the lists for its context.
1654 * Must be called with ctx->mutex and ctx->lock held.
1657 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1659 WARN_ON_ONCE(event->ctx != ctx);
1660 lockdep_assert_held(&ctx->lock);
1663 * We can have double detach due to exit/hot-unplug + close.
1665 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1668 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1670 list_update_cgroup_event(event, ctx, false);
1673 if (event->attr.inherit_stat)
1676 list_del_rcu(&event->event_entry);
1678 if (event->group_leader == event)
1679 list_del_init(&event->group_entry);
1681 update_group_times(event);
1684 * If event was in error state, then keep it
1685 * that way, otherwise bogus counts will be
1686 * returned on read(). The only way to get out
1687 * of error state is by explicit re-enabling
1690 if (event->state > PERF_EVENT_STATE_OFF)
1691 event->state = PERF_EVENT_STATE_OFF;
1696 static void perf_group_detach(struct perf_event *event)
1698 struct perf_event *sibling, *tmp;
1699 struct list_head *list = NULL;
1701 lockdep_assert_held(&event->ctx->lock);
1704 * We can have double detach due to exit/hot-unplug + close.
1706 if (!(event->attach_state & PERF_ATTACH_GROUP))
1709 event->attach_state &= ~PERF_ATTACH_GROUP;
1712 * If this is a sibling, remove it from its group.
1714 if (event->group_leader != event) {
1715 list_del_init(&event->group_entry);
1716 event->group_leader->nr_siblings--;
1720 if (!list_empty(&event->group_entry))
1721 list = &event->group_entry;
1724 * If this was a group event with sibling events then
1725 * upgrade the siblings to singleton events by adding them
1726 * to whatever list we are on.
1728 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1730 list_move_tail(&sibling->group_entry, list);
1731 sibling->group_leader = sibling;
1733 /* Inherit group flags from the previous leader */
1734 sibling->group_caps = event->group_caps;
1736 WARN_ON_ONCE(sibling->ctx != event->ctx);
1740 perf_event__header_size(event->group_leader);
1742 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1743 perf_event__header_size(tmp);
1746 static bool is_orphaned_event(struct perf_event *event)
1748 return event->state == PERF_EVENT_STATE_DEAD;
1751 static inline int __pmu_filter_match(struct perf_event *event)
1753 struct pmu *pmu = event->pmu;
1754 return pmu->filter_match ? pmu->filter_match(event) : 1;
1758 * Check whether we should attempt to schedule an event group based on
1759 * PMU-specific filtering. An event group can consist of HW and SW events,
1760 * potentially with a SW leader, so we must check all the filters, to
1761 * determine whether a group is schedulable:
1763 static inline int pmu_filter_match(struct perf_event *event)
1765 struct perf_event *child;
1767 if (!__pmu_filter_match(event))
1770 list_for_each_entry(child, &event->sibling_list, group_entry) {
1771 if (!__pmu_filter_match(child))
1779 event_filter_match(struct perf_event *event)
1781 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1782 perf_cgroup_match(event) && pmu_filter_match(event);
1786 event_sched_out(struct perf_event *event,
1787 struct perf_cpu_context *cpuctx,
1788 struct perf_event_context *ctx)
1790 u64 tstamp = perf_event_time(event);
1793 WARN_ON_ONCE(event->ctx != ctx);
1794 lockdep_assert_held(&ctx->lock);
1797 * An event which could not be activated because of
1798 * filter mismatch still needs to have its timings
1799 * maintained, otherwise bogus information is return
1800 * via read() for time_enabled, time_running:
1802 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1803 !event_filter_match(event)) {
1804 delta = tstamp - event->tstamp_stopped;
1805 event->tstamp_running += delta;
1806 event->tstamp_stopped = tstamp;
1809 if (event->state != PERF_EVENT_STATE_ACTIVE)
1812 perf_pmu_disable(event->pmu);
1814 event->tstamp_stopped = tstamp;
1815 event->pmu->del(event, 0);
1817 event->state = PERF_EVENT_STATE_INACTIVE;
1818 if (event->pending_disable) {
1819 event->pending_disable = 0;
1820 event->state = PERF_EVENT_STATE_OFF;
1823 if (!is_software_event(event))
1824 cpuctx->active_oncpu--;
1825 if (!--ctx->nr_active)
1826 perf_event_ctx_deactivate(ctx);
1827 if (event->attr.freq && event->attr.sample_freq)
1829 if (event->attr.exclusive || !cpuctx->active_oncpu)
1830 cpuctx->exclusive = 0;
1832 perf_pmu_enable(event->pmu);
1836 group_sched_out(struct perf_event *group_event,
1837 struct perf_cpu_context *cpuctx,
1838 struct perf_event_context *ctx)
1840 struct perf_event *event;
1841 int state = group_event->state;
1843 perf_pmu_disable(ctx->pmu);
1845 event_sched_out(group_event, cpuctx, ctx);
1848 * Schedule out siblings (if any):
1850 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1851 event_sched_out(event, cpuctx, ctx);
1853 perf_pmu_enable(ctx->pmu);
1855 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1856 cpuctx->exclusive = 0;
1859 #define DETACH_GROUP 0x01UL
1862 * Cross CPU call to remove a performance event
1864 * We disable the event on the hardware level first. After that we
1865 * remove it from the context list.
1868 __perf_remove_from_context(struct perf_event *event,
1869 struct perf_cpu_context *cpuctx,
1870 struct perf_event_context *ctx,
1873 unsigned long flags = (unsigned long)info;
1875 event_sched_out(event, cpuctx, ctx);
1876 if (flags & DETACH_GROUP)
1877 perf_group_detach(event);
1878 list_del_event(event, ctx);
1880 if (!ctx->nr_events && ctx->is_active) {
1883 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1884 cpuctx->task_ctx = NULL;
1890 * Remove the event from a task's (or a CPU's) list of events.
1892 * If event->ctx is a cloned context, callers must make sure that
1893 * every task struct that event->ctx->task could possibly point to
1894 * remains valid. This is OK when called from perf_release since
1895 * that only calls us on the top-level context, which can't be a clone.
1896 * When called from perf_event_exit_task, it's OK because the
1897 * context has been detached from its task.
1899 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1901 struct perf_event_context *ctx = event->ctx;
1903 lockdep_assert_held(&ctx->mutex);
1905 event_function_call(event, __perf_remove_from_context, (void *)flags);
1908 * The above event_function_call() can NO-OP when it hits
1909 * TASK_TOMBSTONE. In that case we must already have been detached
1910 * from the context (by perf_event_exit_event()) but the grouping
1911 * might still be in-tact.
1913 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1914 if ((flags & DETACH_GROUP) &&
1915 (event->attach_state & PERF_ATTACH_GROUP)) {
1917 * Since in that case we cannot possibly be scheduled, simply
1920 raw_spin_lock_irq(&ctx->lock);
1921 perf_group_detach(event);
1922 raw_spin_unlock_irq(&ctx->lock);
1927 * Cross CPU call to disable a performance event
1929 static void __perf_event_disable(struct perf_event *event,
1930 struct perf_cpu_context *cpuctx,
1931 struct perf_event_context *ctx,
1934 if (event->state < PERF_EVENT_STATE_INACTIVE)
1937 update_context_time(ctx);
1938 update_cgrp_time_from_event(event);
1939 update_group_times(event);
1940 if (event == event->group_leader)
1941 group_sched_out(event, cpuctx, ctx);
1943 event_sched_out(event, cpuctx, ctx);
1944 event->state = PERF_EVENT_STATE_OFF;
1950 * If event->ctx is a cloned context, callers must make sure that
1951 * every task struct that event->ctx->task could possibly point to
1952 * remains valid. This condition is satisifed when called through
1953 * perf_event_for_each_child or perf_event_for_each because they
1954 * hold the top-level event's child_mutex, so any descendant that
1955 * goes to exit will block in perf_event_exit_event().
1957 * When called from perf_pending_event it's OK because event->ctx
1958 * is the current context on this CPU and preemption is disabled,
1959 * hence we can't get into perf_event_task_sched_out for this context.
1961 static void _perf_event_disable(struct perf_event *event)
1963 struct perf_event_context *ctx = event->ctx;
1965 raw_spin_lock_irq(&ctx->lock);
1966 if (event->state <= PERF_EVENT_STATE_OFF) {
1967 raw_spin_unlock_irq(&ctx->lock);
1970 raw_spin_unlock_irq(&ctx->lock);
1972 event_function_call(event, __perf_event_disable, NULL);
1975 void perf_event_disable_local(struct perf_event *event)
1977 event_function_local(event, __perf_event_disable, NULL);
1981 * Strictly speaking kernel users cannot create groups and therefore this
1982 * interface does not need the perf_event_ctx_lock() magic.
1984 void perf_event_disable(struct perf_event *event)
1986 struct perf_event_context *ctx;
1988 ctx = perf_event_ctx_lock(event);
1989 _perf_event_disable(event);
1990 perf_event_ctx_unlock(event, ctx);
1992 EXPORT_SYMBOL_GPL(perf_event_disable);
1994 void perf_event_disable_inatomic(struct perf_event *event)
1996 event->pending_disable = 1;
1997 irq_work_queue(&event->pending);
2000 static void perf_set_shadow_time(struct perf_event *event,
2001 struct perf_event_context *ctx,
2005 * use the correct time source for the time snapshot
2007 * We could get by without this by leveraging the
2008 * fact that to get to this function, the caller
2009 * has most likely already called update_context_time()
2010 * and update_cgrp_time_xx() and thus both timestamp
2011 * are identical (or very close). Given that tstamp is,
2012 * already adjusted for cgroup, we could say that:
2013 * tstamp - ctx->timestamp
2015 * tstamp - cgrp->timestamp.
2017 * Then, in perf_output_read(), the calculation would
2018 * work with no changes because:
2019 * - event is guaranteed scheduled in
2020 * - no scheduled out in between
2021 * - thus the timestamp would be the same
2023 * But this is a bit hairy.
2025 * So instead, we have an explicit cgroup call to remain
2026 * within the time time source all along. We believe it
2027 * is cleaner and simpler to understand.
2029 if (is_cgroup_event(event))
2030 perf_cgroup_set_shadow_time(event, tstamp);
2032 event->shadow_ctx_time = tstamp - ctx->timestamp;
2035 #define MAX_INTERRUPTS (~0ULL)
2037 static void perf_log_throttle(struct perf_event *event, int enable);
2038 static void perf_log_itrace_start(struct perf_event *event);
2041 event_sched_in(struct perf_event *event,
2042 struct perf_cpu_context *cpuctx,
2043 struct perf_event_context *ctx)
2045 u64 tstamp = perf_event_time(event);
2048 lockdep_assert_held(&ctx->lock);
2050 if (event->state <= PERF_EVENT_STATE_OFF)
2053 WRITE_ONCE(event->oncpu, smp_processor_id());
2055 * Order event::oncpu write to happen before the ACTIVE state
2059 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2062 * Unthrottle events, since we scheduled we might have missed several
2063 * ticks already, also for a heavily scheduling task there is little
2064 * guarantee it'll get a tick in a timely manner.
2066 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2067 perf_log_throttle(event, 1);
2068 event->hw.interrupts = 0;
2072 * The new state must be visible before we turn it on in the hardware:
2076 perf_pmu_disable(event->pmu);
2078 perf_set_shadow_time(event, ctx, tstamp);
2080 perf_log_itrace_start(event);
2082 if (event->pmu->add(event, PERF_EF_START)) {
2083 event->state = PERF_EVENT_STATE_INACTIVE;
2089 event->tstamp_running += tstamp - event->tstamp_stopped;
2091 if (!is_software_event(event))
2092 cpuctx->active_oncpu++;
2093 if (!ctx->nr_active++)
2094 perf_event_ctx_activate(ctx);
2095 if (event->attr.freq && event->attr.sample_freq)
2098 if (event->attr.exclusive)
2099 cpuctx->exclusive = 1;
2102 perf_pmu_enable(event->pmu);
2108 group_sched_in(struct perf_event *group_event,
2109 struct perf_cpu_context *cpuctx,
2110 struct perf_event_context *ctx)
2112 struct perf_event *event, *partial_group = NULL;
2113 struct pmu *pmu = ctx->pmu;
2114 u64 now = ctx->time;
2115 bool simulate = false;
2117 if (group_event->state == PERF_EVENT_STATE_OFF)
2120 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2122 if (event_sched_in(group_event, cpuctx, ctx)) {
2123 pmu->cancel_txn(pmu);
2124 perf_mux_hrtimer_restart(cpuctx);
2129 * Schedule in siblings as one group (if any):
2131 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2132 if (event_sched_in(event, cpuctx, ctx)) {
2133 partial_group = event;
2138 if (!pmu->commit_txn(pmu))
2143 * Groups can be scheduled in as one unit only, so undo any
2144 * partial group before returning:
2145 * The events up to the failed event are scheduled out normally,
2146 * tstamp_stopped will be updated.
2148 * The failed events and the remaining siblings need to have
2149 * their timings updated as if they had gone thru event_sched_in()
2150 * and event_sched_out(). This is required to get consistent timings
2151 * across the group. This also takes care of the case where the group
2152 * could never be scheduled by ensuring tstamp_stopped is set to mark
2153 * the time the event was actually stopped, such that time delta
2154 * calculation in update_event_times() is correct.
2156 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2157 if (event == partial_group)
2161 event->tstamp_running += now - event->tstamp_stopped;
2162 event->tstamp_stopped = now;
2164 event_sched_out(event, cpuctx, ctx);
2167 event_sched_out(group_event, cpuctx, ctx);
2169 pmu->cancel_txn(pmu);
2171 perf_mux_hrtimer_restart(cpuctx);
2177 * Work out whether we can put this event group on the CPU now.
2179 static int group_can_go_on(struct perf_event *event,
2180 struct perf_cpu_context *cpuctx,
2184 * Groups consisting entirely of software events can always go on.
2186 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2189 * If an exclusive group is already on, no other hardware
2192 if (cpuctx->exclusive)
2195 * If this group is exclusive and there are already
2196 * events on the CPU, it can't go on.
2198 if (event->attr.exclusive && cpuctx->active_oncpu)
2201 * Otherwise, try to add it if all previous groups were able
2207 static void add_event_to_ctx(struct perf_event *event,
2208 struct perf_event_context *ctx)
2210 u64 tstamp = perf_event_time(event);
2212 list_add_event(event, ctx);
2213 perf_group_attach(event);
2214 event->tstamp_enabled = tstamp;
2215 event->tstamp_running = tstamp;
2216 event->tstamp_stopped = tstamp;
2219 static void ctx_sched_out(struct perf_event_context *ctx,
2220 struct perf_cpu_context *cpuctx,
2221 enum event_type_t event_type);
2223 ctx_sched_in(struct perf_event_context *ctx,
2224 struct perf_cpu_context *cpuctx,
2225 enum event_type_t event_type,
2226 struct task_struct *task);
2228 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2229 struct perf_event_context *ctx)
2231 if (!cpuctx->task_ctx)
2234 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2237 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2240 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2241 struct perf_event_context *ctx,
2242 struct task_struct *task)
2244 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2246 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2247 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2249 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2252 static void ctx_resched(struct perf_cpu_context *cpuctx,
2253 struct perf_event_context *task_ctx)
2255 perf_pmu_disable(cpuctx->ctx.pmu);
2257 task_ctx_sched_out(cpuctx, task_ctx);
2258 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2259 perf_event_sched_in(cpuctx, task_ctx, current);
2260 perf_pmu_enable(cpuctx->ctx.pmu);
2264 * Cross CPU call to install and enable a performance event
2266 * Very similar to remote_function() + event_function() but cannot assume that
2267 * things like ctx->is_active and cpuctx->task_ctx are set.
2269 static int __perf_install_in_context(void *info)
2271 struct perf_event *event = info;
2272 struct perf_event_context *ctx = event->ctx;
2273 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2274 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2275 bool reprogram = true;
2278 raw_spin_lock(&cpuctx->ctx.lock);
2280 raw_spin_lock(&ctx->lock);
2283 reprogram = (ctx->task == current);
2286 * If the task is running, it must be running on this CPU,
2287 * otherwise we cannot reprogram things.
2289 * If its not running, we don't care, ctx->lock will
2290 * serialize against it becoming runnable.
2292 if (task_curr(ctx->task) && !reprogram) {
2297 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2298 } else if (task_ctx) {
2299 raw_spin_lock(&task_ctx->lock);
2303 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2304 add_event_to_ctx(event, ctx);
2305 ctx_resched(cpuctx, task_ctx);
2307 add_event_to_ctx(event, ctx);
2311 perf_ctx_unlock(cpuctx, task_ctx);
2317 * Attach a performance event to a context.
2319 * Very similar to event_function_call, see comment there.
2322 perf_install_in_context(struct perf_event_context *ctx,
2323 struct perf_event *event,
2326 struct task_struct *task = READ_ONCE(ctx->task);
2328 lockdep_assert_held(&ctx->mutex);
2330 if (event->cpu != -1)
2334 * Ensures that if we can observe event->ctx, both the event and ctx
2335 * will be 'complete'. See perf_iterate_sb_cpu().
2337 smp_store_release(&event->ctx, ctx);
2340 cpu_function_call(cpu, __perf_install_in_context, event);
2345 * Should not happen, we validate the ctx is still alive before calling.
2347 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2351 * Installing events is tricky because we cannot rely on ctx->is_active
2352 * to be set in case this is the nr_events 0 -> 1 transition.
2354 * Instead we use task_curr(), which tells us if the task is running.
2355 * However, since we use task_curr() outside of rq::lock, we can race
2356 * against the actual state. This means the result can be wrong.
2358 * If we get a false positive, we retry, this is harmless.
2360 * If we get a false negative, things are complicated. If we are after
2361 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2362 * value must be correct. If we're before, it doesn't matter since
2363 * perf_event_context_sched_in() will program the counter.
2365 * However, this hinges on the remote context switch having observed
2366 * our task->perf_event_ctxp[] store, such that it will in fact take
2367 * ctx::lock in perf_event_context_sched_in().
2369 * We do this by task_function_call(), if the IPI fails to hit the task
2370 * we know any future context switch of task must see the
2371 * perf_event_ctpx[] store.
2375 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2376 * task_cpu() load, such that if the IPI then does not find the task
2377 * running, a future context switch of that task must observe the
2382 if (!task_function_call(task, __perf_install_in_context, event))
2385 raw_spin_lock_irq(&ctx->lock);
2387 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2389 * Cannot happen because we already checked above (which also
2390 * cannot happen), and we hold ctx->mutex, which serializes us
2391 * against perf_event_exit_task_context().
2393 raw_spin_unlock_irq(&ctx->lock);
2397 * If the task is not running, ctx->lock will avoid it becoming so,
2398 * thus we can safely install the event.
2400 if (task_curr(task)) {
2401 raw_spin_unlock_irq(&ctx->lock);
2404 add_event_to_ctx(event, ctx);
2405 raw_spin_unlock_irq(&ctx->lock);
2409 * Put a event into inactive state and update time fields.
2410 * Enabling the leader of a group effectively enables all
2411 * the group members that aren't explicitly disabled, so we
2412 * have to update their ->tstamp_enabled also.
2413 * Note: this works for group members as well as group leaders
2414 * since the non-leader members' sibling_lists will be empty.
2416 static void __perf_event_mark_enabled(struct perf_event *event)
2418 struct perf_event *sub;
2419 u64 tstamp = perf_event_time(event);
2421 event->state = PERF_EVENT_STATE_INACTIVE;
2422 event->tstamp_enabled = tstamp - event->total_time_enabled;
2423 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2424 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2425 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2430 * Cross CPU call to enable a performance event
2432 static void __perf_event_enable(struct perf_event *event,
2433 struct perf_cpu_context *cpuctx,
2434 struct perf_event_context *ctx,
2437 struct perf_event *leader = event->group_leader;
2438 struct perf_event_context *task_ctx;
2440 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2441 event->state <= PERF_EVENT_STATE_ERROR)
2445 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2447 __perf_event_mark_enabled(event);
2449 if (!ctx->is_active)
2452 if (!event_filter_match(event)) {
2453 if (is_cgroup_event(event))
2454 perf_cgroup_defer_enabled(event);
2455 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2460 * If the event is in a group and isn't the group leader,
2461 * then don't put it on unless the group is on.
2463 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2464 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2468 task_ctx = cpuctx->task_ctx;
2470 WARN_ON_ONCE(task_ctx != ctx);
2472 ctx_resched(cpuctx, task_ctx);
2478 * If event->ctx is a cloned context, callers must make sure that
2479 * every task struct that event->ctx->task could possibly point to
2480 * remains valid. This condition is satisfied when called through
2481 * perf_event_for_each_child or perf_event_for_each as described
2482 * for perf_event_disable.
2484 static void _perf_event_enable(struct perf_event *event)
2486 struct perf_event_context *ctx = event->ctx;
2488 raw_spin_lock_irq(&ctx->lock);
2489 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2490 event->state < PERF_EVENT_STATE_ERROR) {
2491 raw_spin_unlock_irq(&ctx->lock);
2496 * If the event is in error state, clear that first.
2498 * That way, if we see the event in error state below, we know that it
2499 * has gone back into error state, as distinct from the task having
2500 * been scheduled away before the cross-call arrived.
2502 if (event->state == PERF_EVENT_STATE_ERROR)
2503 event->state = PERF_EVENT_STATE_OFF;
2504 raw_spin_unlock_irq(&ctx->lock);
2506 event_function_call(event, __perf_event_enable, NULL);
2510 * See perf_event_disable();
2512 void perf_event_enable(struct perf_event *event)
2514 struct perf_event_context *ctx;
2516 ctx = perf_event_ctx_lock(event);
2517 _perf_event_enable(event);
2518 perf_event_ctx_unlock(event, ctx);
2520 EXPORT_SYMBOL_GPL(perf_event_enable);
2522 struct stop_event_data {
2523 struct perf_event *event;
2524 unsigned int restart;
2527 static int __perf_event_stop(void *info)
2529 struct stop_event_data *sd = info;
2530 struct perf_event *event = sd->event;
2532 /* if it's already INACTIVE, do nothing */
2533 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2536 /* matches smp_wmb() in event_sched_in() */
2540 * There is a window with interrupts enabled before we get here,
2541 * so we need to check again lest we try to stop another CPU's event.
2543 if (READ_ONCE(event->oncpu) != smp_processor_id())
2546 event->pmu->stop(event, PERF_EF_UPDATE);
2549 * May race with the actual stop (through perf_pmu_output_stop()),
2550 * but it is only used for events with AUX ring buffer, and such
2551 * events will refuse to restart because of rb::aux_mmap_count==0,
2552 * see comments in perf_aux_output_begin().
2554 * Since this is happening on a event-local CPU, no trace is lost
2558 event->pmu->start(event, 0);
2563 static int perf_event_stop(struct perf_event *event, int restart)
2565 struct stop_event_data sd = {
2572 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2575 /* matches smp_wmb() in event_sched_in() */
2579 * We only want to restart ACTIVE events, so if the event goes
2580 * inactive here (event->oncpu==-1), there's nothing more to do;
2581 * fall through with ret==-ENXIO.
2583 ret = cpu_function_call(READ_ONCE(event->oncpu),
2584 __perf_event_stop, &sd);
2585 } while (ret == -EAGAIN);
2591 * In order to contain the amount of racy and tricky in the address filter
2592 * configuration management, it is a two part process:
2594 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2595 * we update the addresses of corresponding vmas in
2596 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2597 * (p2) when an event is scheduled in (pmu::add), it calls
2598 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2599 * if the generation has changed since the previous call.
2601 * If (p1) happens while the event is active, we restart it to force (p2).
2603 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2604 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2606 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2607 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2609 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2612 void perf_event_addr_filters_sync(struct perf_event *event)
2614 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2616 if (!has_addr_filter(event))
2619 raw_spin_lock(&ifh->lock);
2620 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2621 event->pmu->addr_filters_sync(event);
2622 event->hw.addr_filters_gen = event->addr_filters_gen;
2624 raw_spin_unlock(&ifh->lock);
2626 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2628 static int _perf_event_refresh(struct perf_event *event, int refresh)
2631 * not supported on inherited events
2633 if (event->attr.inherit || !is_sampling_event(event))
2636 atomic_add(refresh, &event->event_limit);
2637 _perf_event_enable(event);
2643 * See perf_event_disable()
2645 int perf_event_refresh(struct perf_event *event, int refresh)
2647 struct perf_event_context *ctx;
2650 ctx = perf_event_ctx_lock(event);
2651 ret = _perf_event_refresh(event, refresh);
2652 perf_event_ctx_unlock(event, ctx);
2656 EXPORT_SYMBOL_GPL(perf_event_refresh);
2658 static void ctx_sched_out(struct perf_event_context *ctx,
2659 struct perf_cpu_context *cpuctx,
2660 enum event_type_t event_type)
2662 int is_active = ctx->is_active;
2663 struct perf_event *event;
2665 lockdep_assert_held(&ctx->lock);
2667 if (likely(!ctx->nr_events)) {
2669 * See __perf_remove_from_context().
2671 WARN_ON_ONCE(ctx->is_active);
2673 WARN_ON_ONCE(cpuctx->task_ctx);
2677 ctx->is_active &= ~event_type;
2678 if (!(ctx->is_active & EVENT_ALL))
2682 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2683 if (!ctx->is_active)
2684 cpuctx->task_ctx = NULL;
2688 * Always update time if it was set; not only when it changes.
2689 * Otherwise we can 'forget' to update time for any but the last
2690 * context we sched out. For example:
2692 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2693 * ctx_sched_out(.event_type = EVENT_PINNED)
2695 * would only update time for the pinned events.
2697 if (is_active & EVENT_TIME) {
2698 /* update (and stop) ctx time */
2699 update_context_time(ctx);
2700 update_cgrp_time_from_cpuctx(cpuctx);
2703 is_active ^= ctx->is_active; /* changed bits */
2705 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2708 perf_pmu_disable(ctx->pmu);
2709 if (is_active & EVENT_PINNED) {
2710 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2711 group_sched_out(event, cpuctx, ctx);
2714 if (is_active & EVENT_FLEXIBLE) {
2715 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2716 group_sched_out(event, cpuctx, ctx);
2718 perf_pmu_enable(ctx->pmu);
2722 * Test whether two contexts are equivalent, i.e. whether they have both been
2723 * cloned from the same version of the same context.
2725 * Equivalence is measured using a generation number in the context that is
2726 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2727 * and list_del_event().
2729 static int context_equiv(struct perf_event_context *ctx1,
2730 struct perf_event_context *ctx2)
2732 lockdep_assert_held(&ctx1->lock);
2733 lockdep_assert_held(&ctx2->lock);
2735 /* Pinning disables the swap optimization */
2736 if (ctx1->pin_count || ctx2->pin_count)
2739 /* If ctx1 is the parent of ctx2 */
2740 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2743 /* If ctx2 is the parent of ctx1 */
2744 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2748 * If ctx1 and ctx2 have the same parent; we flatten the parent
2749 * hierarchy, see perf_event_init_context().
2751 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2752 ctx1->parent_gen == ctx2->parent_gen)
2759 static void __perf_event_sync_stat(struct perf_event *event,
2760 struct perf_event *next_event)
2764 if (!event->attr.inherit_stat)
2768 * Update the event value, we cannot use perf_event_read()
2769 * because we're in the middle of a context switch and have IRQs
2770 * disabled, which upsets smp_call_function_single(), however
2771 * we know the event must be on the current CPU, therefore we
2772 * don't need to use it.
2774 switch (event->state) {
2775 case PERF_EVENT_STATE_ACTIVE:
2776 event->pmu->read(event);
2779 case PERF_EVENT_STATE_INACTIVE:
2780 update_event_times(event);
2788 * In order to keep per-task stats reliable we need to flip the event
2789 * values when we flip the contexts.
2791 value = local64_read(&next_event->count);
2792 value = local64_xchg(&event->count, value);
2793 local64_set(&next_event->count, value);
2795 swap(event->total_time_enabled, next_event->total_time_enabled);
2796 swap(event->total_time_running, next_event->total_time_running);
2799 * Since we swizzled the values, update the user visible data too.
2801 perf_event_update_userpage(event);
2802 perf_event_update_userpage(next_event);
2805 static void perf_event_sync_stat(struct perf_event_context *ctx,
2806 struct perf_event_context *next_ctx)
2808 struct perf_event *event, *next_event;
2813 update_context_time(ctx);
2815 event = list_first_entry(&ctx->event_list,
2816 struct perf_event, event_entry);
2818 next_event = list_first_entry(&next_ctx->event_list,
2819 struct perf_event, event_entry);
2821 while (&event->event_entry != &ctx->event_list &&
2822 &next_event->event_entry != &next_ctx->event_list) {
2824 __perf_event_sync_stat(event, next_event);
2826 event = list_next_entry(event, event_entry);
2827 next_event = list_next_entry(next_event, event_entry);
2831 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2832 struct task_struct *next)
2834 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2835 struct perf_event_context *next_ctx;
2836 struct perf_event_context *parent, *next_parent;
2837 struct perf_cpu_context *cpuctx;
2843 cpuctx = __get_cpu_context(ctx);
2844 if (!cpuctx->task_ctx)
2848 next_ctx = next->perf_event_ctxp[ctxn];
2852 parent = rcu_dereference(ctx->parent_ctx);
2853 next_parent = rcu_dereference(next_ctx->parent_ctx);
2855 /* If neither context have a parent context; they cannot be clones. */
2856 if (!parent && !next_parent)
2859 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2861 * Looks like the two contexts are clones, so we might be
2862 * able to optimize the context switch. We lock both
2863 * contexts and check that they are clones under the
2864 * lock (including re-checking that neither has been
2865 * uncloned in the meantime). It doesn't matter which
2866 * order we take the locks because no other cpu could
2867 * be trying to lock both of these tasks.
2869 raw_spin_lock(&ctx->lock);
2870 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2871 if (context_equiv(ctx, next_ctx)) {
2872 WRITE_ONCE(ctx->task, next);
2873 WRITE_ONCE(next_ctx->task, task);
2875 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2878 * RCU_INIT_POINTER here is safe because we've not
2879 * modified the ctx and the above modification of
2880 * ctx->task and ctx->task_ctx_data are immaterial
2881 * since those values are always verified under
2882 * ctx->lock which we're now holding.
2884 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2885 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2889 perf_event_sync_stat(ctx, next_ctx);
2891 raw_spin_unlock(&next_ctx->lock);
2892 raw_spin_unlock(&ctx->lock);
2898 raw_spin_lock(&ctx->lock);
2899 task_ctx_sched_out(cpuctx, ctx);
2900 raw_spin_unlock(&ctx->lock);
2904 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2906 void perf_sched_cb_dec(struct pmu *pmu)
2908 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2910 this_cpu_dec(perf_sched_cb_usages);
2912 if (!--cpuctx->sched_cb_usage)
2913 list_del(&cpuctx->sched_cb_entry);
2917 void perf_sched_cb_inc(struct pmu *pmu)
2919 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2921 if (!cpuctx->sched_cb_usage++)
2922 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2924 this_cpu_inc(perf_sched_cb_usages);
2928 * This function provides the context switch callback to the lower code
2929 * layer. It is invoked ONLY when the context switch callback is enabled.
2931 * This callback is relevant even to per-cpu events; for example multi event
2932 * PEBS requires this to provide PID/TID information. This requires we flush
2933 * all queued PEBS records before we context switch to a new task.
2935 static void perf_pmu_sched_task(struct task_struct *prev,
2936 struct task_struct *next,
2939 struct perf_cpu_context *cpuctx;
2945 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2946 pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */
2948 if (WARN_ON_ONCE(!pmu->sched_task))
2951 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2952 perf_pmu_disable(pmu);
2954 pmu->sched_task(cpuctx->task_ctx, sched_in);
2956 perf_pmu_enable(pmu);
2957 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2961 static void perf_event_switch(struct task_struct *task,
2962 struct task_struct *next_prev, bool sched_in);
2964 #define for_each_task_context_nr(ctxn) \
2965 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2968 * Called from scheduler to remove the events of the current task,
2969 * with interrupts disabled.
2971 * We stop each event and update the event value in event->count.
2973 * This does not protect us against NMI, but disable()
2974 * sets the disabled bit in the control field of event _before_
2975 * accessing the event control register. If a NMI hits, then it will
2976 * not restart the event.
2978 void __perf_event_task_sched_out(struct task_struct *task,
2979 struct task_struct *next)
2983 if (__this_cpu_read(perf_sched_cb_usages))
2984 perf_pmu_sched_task(task, next, false);
2986 if (atomic_read(&nr_switch_events))
2987 perf_event_switch(task, next, false);
2989 for_each_task_context_nr(ctxn)
2990 perf_event_context_sched_out(task, ctxn, next);
2993 * if cgroup events exist on this CPU, then we need
2994 * to check if we have to switch out PMU state.
2995 * cgroup event are system-wide mode only
2997 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2998 perf_cgroup_sched_out(task, next);
3002 * Called with IRQs disabled
3004 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3005 enum event_type_t event_type)
3007 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3011 ctx_pinned_sched_in(struct perf_event_context *ctx,
3012 struct perf_cpu_context *cpuctx)
3014 struct perf_event *event;
3016 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3017 if (event->state <= PERF_EVENT_STATE_OFF)
3019 if (!event_filter_match(event))
3022 /* may need to reset tstamp_enabled */
3023 if (is_cgroup_event(event))
3024 perf_cgroup_mark_enabled(event, ctx);
3026 if (group_can_go_on(event, cpuctx, 1))
3027 group_sched_in(event, cpuctx, ctx);
3030 * If this pinned group hasn't been scheduled,
3031 * put it in error state.
3033 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3034 update_group_times(event);
3035 event->state = PERF_EVENT_STATE_ERROR;
3041 ctx_flexible_sched_in(struct perf_event_context *ctx,
3042 struct perf_cpu_context *cpuctx)
3044 struct perf_event *event;
3047 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3048 /* Ignore events in OFF or ERROR state */
3049 if (event->state <= PERF_EVENT_STATE_OFF)
3052 * Listen to the 'cpu' scheduling filter constraint
3055 if (!event_filter_match(event))
3058 /* may need to reset tstamp_enabled */
3059 if (is_cgroup_event(event))
3060 perf_cgroup_mark_enabled(event, ctx);
3062 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3063 if (group_sched_in(event, cpuctx, ctx))
3070 ctx_sched_in(struct perf_event_context *ctx,
3071 struct perf_cpu_context *cpuctx,
3072 enum event_type_t event_type,
3073 struct task_struct *task)
3075 int is_active = ctx->is_active;
3078 lockdep_assert_held(&ctx->lock);
3080 if (likely(!ctx->nr_events))
3083 ctx->is_active |= (event_type | EVENT_TIME);
3086 cpuctx->task_ctx = ctx;
3088 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3091 is_active ^= ctx->is_active; /* changed bits */
3093 if (is_active & EVENT_TIME) {
3094 /* start ctx time */
3096 ctx->timestamp = now;
3097 perf_cgroup_set_timestamp(task, ctx);
3101 * First go through the list and put on any pinned groups
3102 * in order to give them the best chance of going on.
3104 if (is_active & EVENT_PINNED)
3105 ctx_pinned_sched_in(ctx, cpuctx);
3107 /* Then walk through the lower prio flexible groups */
3108 if (is_active & EVENT_FLEXIBLE)
3109 ctx_flexible_sched_in(ctx, cpuctx);
3112 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3113 enum event_type_t event_type,
3114 struct task_struct *task)
3116 struct perf_event_context *ctx = &cpuctx->ctx;
3118 ctx_sched_in(ctx, cpuctx, event_type, task);
3121 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3122 struct task_struct *task)
3124 struct perf_cpu_context *cpuctx;
3126 cpuctx = __get_cpu_context(ctx);
3127 if (cpuctx->task_ctx == ctx)
3130 perf_ctx_lock(cpuctx, ctx);
3131 perf_pmu_disable(ctx->pmu);
3133 * We want to keep the following priority order:
3134 * cpu pinned (that don't need to move), task pinned,
3135 * cpu flexible, task flexible.
3137 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3138 perf_event_sched_in(cpuctx, ctx, task);
3139 perf_pmu_enable(ctx->pmu);
3140 perf_ctx_unlock(cpuctx, ctx);
3144 * Called from scheduler to add the events of the current task
3145 * with interrupts disabled.
3147 * We restore the event value and then enable it.
3149 * This does not protect us against NMI, but enable()
3150 * sets the enabled bit in the control field of event _before_
3151 * accessing the event control register. If a NMI hits, then it will
3152 * keep the event running.
3154 void __perf_event_task_sched_in(struct task_struct *prev,
3155 struct task_struct *task)
3157 struct perf_event_context *ctx;
3161 * If cgroup events exist on this CPU, then we need to check if we have
3162 * to switch in PMU state; cgroup event are system-wide mode only.
3164 * Since cgroup events are CPU events, we must schedule these in before
3165 * we schedule in the task events.
3167 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3168 perf_cgroup_sched_in(prev, task);
3170 for_each_task_context_nr(ctxn) {
3171 ctx = task->perf_event_ctxp[ctxn];
3175 perf_event_context_sched_in(ctx, task);
3178 if (atomic_read(&nr_switch_events))
3179 perf_event_switch(task, prev, true);
3181 if (__this_cpu_read(perf_sched_cb_usages))
3182 perf_pmu_sched_task(prev, task, true);
3185 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3187 u64 frequency = event->attr.sample_freq;
3188 u64 sec = NSEC_PER_SEC;
3189 u64 divisor, dividend;
3191 int count_fls, nsec_fls, frequency_fls, sec_fls;
3193 count_fls = fls64(count);
3194 nsec_fls = fls64(nsec);
3195 frequency_fls = fls64(frequency);
3199 * We got @count in @nsec, with a target of sample_freq HZ
3200 * the target period becomes:
3203 * period = -------------------
3204 * @nsec * sample_freq
3209 * Reduce accuracy by one bit such that @a and @b converge
3210 * to a similar magnitude.
3212 #define REDUCE_FLS(a, b) \
3214 if (a##_fls > b##_fls) { \
3224 * Reduce accuracy until either term fits in a u64, then proceed with
3225 * the other, so that finally we can do a u64/u64 division.
3227 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3228 REDUCE_FLS(nsec, frequency);
3229 REDUCE_FLS(sec, count);
3232 if (count_fls + sec_fls > 64) {
3233 divisor = nsec * frequency;
3235 while (count_fls + sec_fls > 64) {
3236 REDUCE_FLS(count, sec);
3240 dividend = count * sec;
3242 dividend = count * sec;
3244 while (nsec_fls + frequency_fls > 64) {
3245 REDUCE_FLS(nsec, frequency);
3249 divisor = nsec * frequency;
3255 return div64_u64(dividend, divisor);
3258 static DEFINE_PER_CPU(int, perf_throttled_count);
3259 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3261 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3263 struct hw_perf_event *hwc = &event->hw;
3264 s64 period, sample_period;
3267 period = perf_calculate_period(event, nsec, count);
3269 delta = (s64)(period - hwc->sample_period);
3270 delta = (delta + 7) / 8; /* low pass filter */
3272 sample_period = hwc->sample_period + delta;
3277 hwc->sample_period = sample_period;
3279 if (local64_read(&hwc->period_left) > 8*sample_period) {
3281 event->pmu->stop(event, PERF_EF_UPDATE);
3283 local64_set(&hwc->period_left, 0);
3286 event->pmu->start(event, PERF_EF_RELOAD);
3291 * combine freq adjustment with unthrottling to avoid two passes over the
3292 * events. At the same time, make sure, having freq events does not change
3293 * the rate of unthrottling as that would introduce bias.
3295 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3298 struct perf_event *event;
3299 struct hw_perf_event *hwc;
3300 u64 now, period = TICK_NSEC;
3304 * only need to iterate over all events iff:
3305 * - context have events in frequency mode (needs freq adjust)
3306 * - there are events to unthrottle on this cpu
3308 if (!(ctx->nr_freq || needs_unthr))
3311 raw_spin_lock(&ctx->lock);
3312 perf_pmu_disable(ctx->pmu);
3314 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3315 if (event->state != PERF_EVENT_STATE_ACTIVE)
3318 if (!event_filter_match(event))
3321 perf_pmu_disable(event->pmu);
3325 if (hwc->interrupts == MAX_INTERRUPTS) {
3326 hwc->interrupts = 0;
3327 perf_log_throttle(event, 1);
3328 event->pmu->start(event, 0);
3331 if (!event->attr.freq || !event->attr.sample_freq)
3335 * stop the event and update event->count
3337 event->pmu->stop(event, PERF_EF_UPDATE);
3339 now = local64_read(&event->count);
3340 delta = now - hwc->freq_count_stamp;
3341 hwc->freq_count_stamp = now;
3345 * reload only if value has changed
3346 * we have stopped the event so tell that
3347 * to perf_adjust_period() to avoid stopping it
3351 perf_adjust_period(event, period, delta, false);
3353 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3355 perf_pmu_enable(event->pmu);
3358 perf_pmu_enable(ctx->pmu);
3359 raw_spin_unlock(&ctx->lock);
3363 * Round-robin a context's events:
3365 static void rotate_ctx(struct perf_event_context *ctx)
3368 * Rotate the first entry last of non-pinned groups. Rotation might be
3369 * disabled by the inheritance code.
3371 if (!ctx->rotate_disable)
3372 list_rotate_left(&ctx->flexible_groups);
3375 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3377 struct perf_event_context *ctx = NULL;
3380 if (cpuctx->ctx.nr_events) {
3381 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3385 ctx = cpuctx->task_ctx;
3386 if (ctx && ctx->nr_events) {
3387 if (ctx->nr_events != ctx->nr_active)
3394 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3395 perf_pmu_disable(cpuctx->ctx.pmu);
3397 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3399 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3401 rotate_ctx(&cpuctx->ctx);
3405 perf_event_sched_in(cpuctx, ctx, current);
3407 perf_pmu_enable(cpuctx->ctx.pmu);
3408 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3414 void perf_event_task_tick(void)
3416 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3417 struct perf_event_context *ctx, *tmp;
3420 WARN_ON(!irqs_disabled());
3422 __this_cpu_inc(perf_throttled_seq);
3423 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3424 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3426 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3427 perf_adjust_freq_unthr_context(ctx, throttled);
3430 static int event_enable_on_exec(struct perf_event *event,
3431 struct perf_event_context *ctx)
3433 if (!event->attr.enable_on_exec)
3436 event->attr.enable_on_exec = 0;
3437 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3440 __perf_event_mark_enabled(event);
3446 * Enable all of a task's events that have been marked enable-on-exec.
3447 * This expects task == current.
3449 static void perf_event_enable_on_exec(int ctxn)
3451 struct perf_event_context *ctx, *clone_ctx = NULL;
3452 struct perf_cpu_context *cpuctx;
3453 struct perf_event *event;
3454 unsigned long flags;
3457 local_irq_save(flags);
3458 ctx = current->perf_event_ctxp[ctxn];
3459 if (!ctx || !ctx->nr_events)
3462 cpuctx = __get_cpu_context(ctx);
3463 perf_ctx_lock(cpuctx, ctx);
3464 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3465 list_for_each_entry(event, &ctx->event_list, event_entry)
3466 enabled |= event_enable_on_exec(event, ctx);
3469 * Unclone and reschedule this context if we enabled any event.
3472 clone_ctx = unclone_ctx(ctx);
3473 ctx_resched(cpuctx, ctx);
3475 perf_ctx_unlock(cpuctx, ctx);
3478 local_irq_restore(flags);
3484 struct perf_read_data {
3485 struct perf_event *event;
3490 static int find_cpu_to_read(struct perf_event *event, int local_cpu)
3492 int event_cpu = event->oncpu;
3493 u16 local_pkg, event_pkg;
3495 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3496 event_pkg = topology_physical_package_id(event_cpu);
3497 local_pkg = topology_physical_package_id(local_cpu);
3499 if (event_pkg == local_pkg)
3507 * Cross CPU call to read the hardware event
3509 static void __perf_event_read(void *info)
3511 struct perf_read_data *data = info;
3512 struct perf_event *sub, *event = data->event;
3513 struct perf_event_context *ctx = event->ctx;
3514 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3515 struct pmu *pmu = event->pmu;
3518 * If this is a task context, we need to check whether it is
3519 * the current task context of this cpu. If not it has been
3520 * scheduled out before the smp call arrived. In that case
3521 * event->count would have been updated to a recent sample
3522 * when the event was scheduled out.
3524 if (ctx->task && cpuctx->task_ctx != ctx)
3527 raw_spin_lock(&ctx->lock);
3528 if (ctx->is_active) {
3529 update_context_time(ctx);
3530 update_cgrp_time_from_event(event);
3533 update_event_times(event);
3534 if (event->state != PERF_EVENT_STATE_ACTIVE)
3543 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3547 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3548 update_event_times(sub);
3549 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3551 * Use sibling's PMU rather than @event's since
3552 * sibling could be on different (eg: software) PMU.
3554 sub->pmu->read(sub);
3558 data->ret = pmu->commit_txn(pmu);
3561 raw_spin_unlock(&ctx->lock);
3564 static inline u64 perf_event_count(struct perf_event *event)
3566 if (event->pmu->count)
3567 return event->pmu->count(event);
3569 return __perf_event_count(event);
3573 * NMI-safe method to read a local event, that is an event that
3575 * - either for the current task, or for this CPU
3576 * - does not have inherit set, for inherited task events
3577 * will not be local and we cannot read them atomically
3578 * - must not have a pmu::count method
3580 u64 perf_event_read_local(struct perf_event *event)
3582 unsigned long flags;
3586 * Disabling interrupts avoids all counter scheduling (context
3587 * switches, timer based rotation and IPIs).
3589 local_irq_save(flags);
3591 /* If this is a per-task event, it must be for current */
3592 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3593 event->hw.target != current);
3595 /* If this is a per-CPU event, it must be for this CPU */
3596 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3597 event->cpu != smp_processor_id());
3600 * It must not be an event with inherit set, we cannot read
3601 * all child counters from atomic context.
3603 WARN_ON_ONCE(event->attr.inherit);
3606 * It must not have a pmu::count method, those are not
3609 WARN_ON_ONCE(event->pmu->count);
3612 * If the event is currently on this CPU, its either a per-task event,
3613 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3616 if (event->oncpu == smp_processor_id())
3617 event->pmu->read(event);
3619 val = local64_read(&event->count);
3620 local_irq_restore(flags);
3625 static int perf_event_read(struct perf_event *event, bool group)
3627 int ret = 0, cpu_to_read, local_cpu;
3630 * If event is enabled and currently active on a CPU, update the
3631 * value in the event structure:
3633 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3634 struct perf_read_data data = {
3640 local_cpu = get_cpu();
3641 cpu_to_read = find_cpu_to_read(event, local_cpu);
3645 * Purposely ignore the smp_call_function_single() return
3648 * If event->oncpu isn't a valid CPU it means the event got
3649 * scheduled out and that will have updated the event count.
3651 * Therefore, either way, we'll have an up-to-date event count
3654 (void)smp_call_function_single(cpu_to_read, __perf_event_read, &data, 1);
3656 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3657 struct perf_event_context *ctx = event->ctx;
3658 unsigned long flags;
3660 raw_spin_lock_irqsave(&ctx->lock, flags);
3662 * may read while context is not active
3663 * (e.g., thread is blocked), in that case
3664 * we cannot update context time
3666 if (ctx->is_active) {
3667 update_context_time(ctx);
3668 update_cgrp_time_from_event(event);
3671 update_group_times(event);
3673 update_event_times(event);
3674 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3681 * Initialize the perf_event context in a task_struct:
3683 static void __perf_event_init_context(struct perf_event_context *ctx)
3685 raw_spin_lock_init(&ctx->lock);
3686 mutex_init(&ctx->mutex);
3687 INIT_LIST_HEAD(&ctx->active_ctx_list);
3688 INIT_LIST_HEAD(&ctx->pinned_groups);
3689 INIT_LIST_HEAD(&ctx->flexible_groups);
3690 INIT_LIST_HEAD(&ctx->event_list);
3691 atomic_set(&ctx->refcount, 1);
3694 static struct perf_event_context *
3695 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3697 struct perf_event_context *ctx;
3699 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3703 __perf_event_init_context(ctx);
3706 get_task_struct(task);
3713 static struct task_struct *
3714 find_lively_task_by_vpid(pid_t vpid)
3716 struct task_struct *task;
3722 task = find_task_by_vpid(vpid);
3724 get_task_struct(task);
3728 return ERR_PTR(-ESRCH);
3734 * Returns a matching context with refcount and pincount.
3736 static struct perf_event_context *
3737 find_get_context(struct pmu *pmu, struct task_struct *task,
3738 struct perf_event *event)
3740 struct perf_event_context *ctx, *clone_ctx = NULL;
3741 struct perf_cpu_context *cpuctx;
3742 void *task_ctx_data = NULL;
3743 unsigned long flags;
3745 int cpu = event->cpu;
3748 /* Must be root to operate on a CPU event: */
3749 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3750 return ERR_PTR(-EACCES);
3753 * We could be clever and allow to attach a event to an
3754 * offline CPU and activate it when the CPU comes up, but
3757 if (!cpu_online(cpu))
3758 return ERR_PTR(-ENODEV);
3760 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3769 ctxn = pmu->task_ctx_nr;
3773 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3774 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3775 if (!task_ctx_data) {
3782 ctx = perf_lock_task_context(task, ctxn, &flags);
3784 clone_ctx = unclone_ctx(ctx);
3787 if (task_ctx_data && !ctx->task_ctx_data) {
3788 ctx->task_ctx_data = task_ctx_data;
3789 task_ctx_data = NULL;
3791 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3796 ctx = alloc_perf_context(pmu, task);
3801 if (task_ctx_data) {
3802 ctx->task_ctx_data = task_ctx_data;
3803 task_ctx_data = NULL;
3807 mutex_lock(&task->perf_event_mutex);
3809 * If it has already passed perf_event_exit_task().
3810 * we must see PF_EXITING, it takes this mutex too.
3812 if (task->flags & PF_EXITING)
3814 else if (task->perf_event_ctxp[ctxn])
3819 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3821 mutex_unlock(&task->perf_event_mutex);
3823 if (unlikely(err)) {
3832 kfree(task_ctx_data);
3836 kfree(task_ctx_data);
3837 return ERR_PTR(err);
3840 static void perf_event_free_filter(struct perf_event *event);
3841 static void perf_event_free_bpf_prog(struct perf_event *event);
3843 static void free_event_rcu(struct rcu_head *head)
3845 struct perf_event *event;
3847 event = container_of(head, struct perf_event, rcu_head);
3849 put_pid_ns(event->ns);
3850 perf_event_free_filter(event);
3854 static void ring_buffer_attach(struct perf_event *event,
3855 struct ring_buffer *rb);
3857 static void detach_sb_event(struct perf_event *event)
3859 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3861 raw_spin_lock(&pel->lock);
3862 list_del_rcu(&event->sb_list);
3863 raw_spin_unlock(&pel->lock);
3866 static bool is_sb_event(struct perf_event *event)
3868 struct perf_event_attr *attr = &event->attr;
3873 if (event->attach_state & PERF_ATTACH_TASK)
3876 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3877 attr->comm || attr->comm_exec ||
3879 attr->context_switch)
3884 static void unaccount_pmu_sb_event(struct perf_event *event)
3886 if (is_sb_event(event))
3887 detach_sb_event(event);
3890 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3895 if (is_cgroup_event(event))
3896 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3899 #ifdef CONFIG_NO_HZ_FULL
3900 static DEFINE_SPINLOCK(nr_freq_lock);
3903 static void unaccount_freq_event_nohz(void)
3905 #ifdef CONFIG_NO_HZ_FULL
3906 spin_lock(&nr_freq_lock);
3907 if (atomic_dec_and_test(&nr_freq_events))
3908 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3909 spin_unlock(&nr_freq_lock);
3913 static void unaccount_freq_event(void)
3915 if (tick_nohz_full_enabled())
3916 unaccount_freq_event_nohz();
3918 atomic_dec(&nr_freq_events);
3921 static void unaccount_event(struct perf_event *event)
3928 if (event->attach_state & PERF_ATTACH_TASK)
3930 if (event->attr.mmap || event->attr.mmap_data)
3931 atomic_dec(&nr_mmap_events);
3932 if (event->attr.comm)
3933 atomic_dec(&nr_comm_events);
3934 if (event->attr.task)
3935 atomic_dec(&nr_task_events);
3936 if (event->attr.freq)
3937 unaccount_freq_event();
3938 if (event->attr.context_switch) {
3940 atomic_dec(&nr_switch_events);
3942 if (is_cgroup_event(event))
3944 if (has_branch_stack(event))
3948 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3949 schedule_delayed_work(&perf_sched_work, HZ);
3952 unaccount_event_cpu(event, event->cpu);
3954 unaccount_pmu_sb_event(event);
3957 static void perf_sched_delayed(struct work_struct *work)
3959 mutex_lock(&perf_sched_mutex);
3960 if (atomic_dec_and_test(&perf_sched_count))
3961 static_branch_disable(&perf_sched_events);
3962 mutex_unlock(&perf_sched_mutex);
3966 * The following implement mutual exclusion of events on "exclusive" pmus
3967 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3968 * at a time, so we disallow creating events that might conflict, namely:
3970 * 1) cpu-wide events in the presence of per-task events,
3971 * 2) per-task events in the presence of cpu-wide events,
3972 * 3) two matching events on the same context.
3974 * The former two cases are handled in the allocation path (perf_event_alloc(),
3975 * _free_event()), the latter -- before the first perf_install_in_context().
3977 static int exclusive_event_init(struct perf_event *event)
3979 struct pmu *pmu = event->pmu;
3981 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3985 * Prevent co-existence of per-task and cpu-wide events on the
3986 * same exclusive pmu.
3988 * Negative pmu::exclusive_cnt means there are cpu-wide
3989 * events on this "exclusive" pmu, positive means there are
3992 * Since this is called in perf_event_alloc() path, event::ctx
3993 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3994 * to mean "per-task event", because unlike other attach states it
3995 * never gets cleared.
3997 if (event->attach_state & PERF_ATTACH_TASK) {
3998 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4001 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4008 static void exclusive_event_destroy(struct perf_event *event)
4010 struct pmu *pmu = event->pmu;
4012 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4015 /* see comment in exclusive_event_init() */
4016 if (event->attach_state & PERF_ATTACH_TASK)
4017 atomic_dec(&pmu->exclusive_cnt);
4019 atomic_inc(&pmu->exclusive_cnt);
4022 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4024 if ((e1->pmu == e2->pmu) &&
4025 (e1->cpu == e2->cpu ||
4032 /* Called under the same ctx::mutex as perf_install_in_context() */
4033 static bool exclusive_event_installable(struct perf_event *event,
4034 struct perf_event_context *ctx)
4036 struct perf_event *iter_event;
4037 struct pmu *pmu = event->pmu;
4039 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4042 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4043 if (exclusive_event_match(iter_event, event))
4050 static void perf_addr_filters_splice(struct perf_event *event,
4051 struct list_head *head);
4053 static void _free_event(struct perf_event *event)
4055 irq_work_sync(&event->pending);
4057 unaccount_event(event);
4061 * Can happen when we close an event with re-directed output.
4063 * Since we have a 0 refcount, perf_mmap_close() will skip
4064 * over us; possibly making our ring_buffer_put() the last.
4066 mutex_lock(&event->mmap_mutex);
4067 ring_buffer_attach(event, NULL);
4068 mutex_unlock(&event->mmap_mutex);
4071 if (is_cgroup_event(event))
4072 perf_detach_cgroup(event);
4074 if (!event->parent) {
4075 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4076 put_callchain_buffers();
4079 perf_event_free_bpf_prog(event);
4080 perf_addr_filters_splice(event, NULL);
4081 kfree(event->addr_filters_offs);
4084 event->destroy(event);
4087 put_ctx(event->ctx);
4089 exclusive_event_destroy(event);
4090 module_put(event->pmu->module);
4092 call_rcu(&event->rcu_head, free_event_rcu);
4096 * Used to free events which have a known refcount of 1, such as in error paths
4097 * where the event isn't exposed yet and inherited events.
4099 static void free_event(struct perf_event *event)
4101 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4102 "unexpected event refcount: %ld; ptr=%p\n",
4103 atomic_long_read(&event->refcount), event)) {
4104 /* leak to avoid use-after-free */
4112 * Remove user event from the owner task.
4114 static void perf_remove_from_owner(struct perf_event *event)
4116 struct task_struct *owner;
4120 * Matches the smp_store_release() in perf_event_exit_task(). If we
4121 * observe !owner it means the list deletion is complete and we can
4122 * indeed free this event, otherwise we need to serialize on
4123 * owner->perf_event_mutex.
4125 owner = lockless_dereference(event->owner);
4128 * Since delayed_put_task_struct() also drops the last
4129 * task reference we can safely take a new reference
4130 * while holding the rcu_read_lock().
4132 get_task_struct(owner);
4138 * If we're here through perf_event_exit_task() we're already
4139 * holding ctx->mutex which would be an inversion wrt. the
4140 * normal lock order.
4142 * However we can safely take this lock because its the child
4145 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4148 * We have to re-check the event->owner field, if it is cleared
4149 * we raced with perf_event_exit_task(), acquiring the mutex
4150 * ensured they're done, and we can proceed with freeing the
4154 list_del_init(&event->owner_entry);
4155 smp_store_release(&event->owner, NULL);
4157 mutex_unlock(&owner->perf_event_mutex);
4158 put_task_struct(owner);
4162 static void put_event(struct perf_event *event)
4164 if (!atomic_long_dec_and_test(&event->refcount))
4171 * Kill an event dead; while event:refcount will preserve the event
4172 * object, it will not preserve its functionality. Once the last 'user'
4173 * gives up the object, we'll destroy the thing.
4175 int perf_event_release_kernel(struct perf_event *event)
4177 struct perf_event_context *ctx = event->ctx;
4178 struct perf_event *child, *tmp;
4181 * If we got here through err_file: fput(event_file); we will not have
4182 * attached to a context yet.
4185 WARN_ON_ONCE(event->attach_state &
4186 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4190 if (!is_kernel_event(event))
4191 perf_remove_from_owner(event);
4193 ctx = perf_event_ctx_lock(event);
4194 WARN_ON_ONCE(ctx->parent_ctx);
4195 perf_remove_from_context(event, DETACH_GROUP);
4197 raw_spin_lock_irq(&ctx->lock);
4199 * Mark this even as STATE_DEAD, there is no external reference to it
4202 * Anybody acquiring event->child_mutex after the below loop _must_
4203 * also see this, most importantly inherit_event() which will avoid
4204 * placing more children on the list.
4206 * Thus this guarantees that we will in fact observe and kill _ALL_
4209 event->state = PERF_EVENT_STATE_DEAD;
4210 raw_spin_unlock_irq(&ctx->lock);
4212 perf_event_ctx_unlock(event, ctx);
4215 mutex_lock(&event->child_mutex);
4216 list_for_each_entry(child, &event->child_list, child_list) {
4219 * Cannot change, child events are not migrated, see the
4220 * comment with perf_event_ctx_lock_nested().
4222 ctx = lockless_dereference(child->ctx);
4224 * Since child_mutex nests inside ctx::mutex, we must jump
4225 * through hoops. We start by grabbing a reference on the ctx.
4227 * Since the event cannot get freed while we hold the
4228 * child_mutex, the context must also exist and have a !0
4234 * Now that we have a ctx ref, we can drop child_mutex, and
4235 * acquire ctx::mutex without fear of it going away. Then we
4236 * can re-acquire child_mutex.
4238 mutex_unlock(&event->child_mutex);
4239 mutex_lock(&ctx->mutex);
4240 mutex_lock(&event->child_mutex);
4243 * Now that we hold ctx::mutex and child_mutex, revalidate our
4244 * state, if child is still the first entry, it didn't get freed
4245 * and we can continue doing so.
4247 tmp = list_first_entry_or_null(&event->child_list,
4248 struct perf_event, child_list);
4250 perf_remove_from_context(child, DETACH_GROUP);
4251 list_del(&child->child_list);
4254 * This matches the refcount bump in inherit_event();
4255 * this can't be the last reference.
4260 mutex_unlock(&event->child_mutex);
4261 mutex_unlock(&ctx->mutex);
4265 mutex_unlock(&event->child_mutex);
4268 put_event(event); /* Must be the 'last' reference */
4271 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4274 * Called when the last reference to the file is gone.
4276 static int perf_release(struct inode *inode, struct file *file)
4278 perf_event_release_kernel(file->private_data);
4282 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4284 struct perf_event *child;
4290 mutex_lock(&event->child_mutex);
4292 (void)perf_event_read(event, false);
4293 total += perf_event_count(event);
4295 *enabled += event->total_time_enabled +
4296 atomic64_read(&event->child_total_time_enabled);
4297 *running += event->total_time_running +
4298 atomic64_read(&event->child_total_time_running);
4300 list_for_each_entry(child, &event->child_list, child_list) {
4301 (void)perf_event_read(child, false);
4302 total += perf_event_count(child);
4303 *enabled += child->total_time_enabled;
4304 *running += child->total_time_running;
4306 mutex_unlock(&event->child_mutex);
4310 EXPORT_SYMBOL_GPL(perf_event_read_value);
4312 static int __perf_read_group_add(struct perf_event *leader,
4313 u64 read_format, u64 *values)
4315 struct perf_event *sub;
4316 int n = 1; /* skip @nr */
4319 ret = perf_event_read(leader, true);
4324 * Since we co-schedule groups, {enabled,running} times of siblings
4325 * will be identical to those of the leader, so we only publish one
4328 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4329 values[n++] += leader->total_time_enabled +
4330 atomic64_read(&leader->child_total_time_enabled);
4333 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4334 values[n++] += leader->total_time_running +
4335 atomic64_read(&leader->child_total_time_running);
4339 * Write {count,id} tuples for every sibling.
4341 values[n++] += perf_event_count(leader);
4342 if (read_format & PERF_FORMAT_ID)
4343 values[n++] = primary_event_id(leader);
4345 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4346 values[n++] += perf_event_count(sub);
4347 if (read_format & PERF_FORMAT_ID)
4348 values[n++] = primary_event_id(sub);
4354 static int perf_read_group(struct perf_event *event,
4355 u64 read_format, char __user *buf)
4357 struct perf_event *leader = event->group_leader, *child;
4358 struct perf_event_context *ctx = leader->ctx;
4362 lockdep_assert_held(&ctx->mutex);
4364 values = kzalloc(event->read_size, GFP_KERNEL);
4368 values[0] = 1 + leader->nr_siblings;
4371 * By locking the child_mutex of the leader we effectively
4372 * lock the child list of all siblings.. XXX explain how.
4374 mutex_lock(&leader->child_mutex);
4376 ret = __perf_read_group_add(leader, read_format, values);
4380 list_for_each_entry(child, &leader->child_list, child_list) {
4381 ret = __perf_read_group_add(child, read_format, values);
4386 mutex_unlock(&leader->child_mutex);
4388 ret = event->read_size;
4389 if (copy_to_user(buf, values, event->read_size))
4394 mutex_unlock(&leader->child_mutex);
4400 static int perf_read_one(struct perf_event *event,
4401 u64 read_format, char __user *buf)
4403 u64 enabled, running;
4407 values[n++] = perf_event_read_value(event, &enabled, &running);
4408 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4409 values[n++] = enabled;
4410 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4411 values[n++] = running;
4412 if (read_format & PERF_FORMAT_ID)
4413 values[n++] = primary_event_id(event);
4415 if (copy_to_user(buf, values, n * sizeof(u64)))
4418 return n * sizeof(u64);
4421 static bool is_event_hup(struct perf_event *event)
4425 if (event->state > PERF_EVENT_STATE_EXIT)
4428 mutex_lock(&event->child_mutex);
4429 no_children = list_empty(&event->child_list);
4430 mutex_unlock(&event->child_mutex);
4435 * Read the performance event - simple non blocking version for now
4438 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4440 u64 read_format = event->attr.read_format;
4444 * Return end-of-file for a read on a event that is in
4445 * error state (i.e. because it was pinned but it couldn't be
4446 * scheduled on to the CPU at some point).
4448 if (event->state == PERF_EVENT_STATE_ERROR)
4451 if (count < event->read_size)
4454 WARN_ON_ONCE(event->ctx->parent_ctx);
4455 if (read_format & PERF_FORMAT_GROUP)
4456 ret = perf_read_group(event, read_format, buf);
4458 ret = perf_read_one(event, read_format, buf);
4464 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4466 struct perf_event *event = file->private_data;
4467 struct perf_event_context *ctx;
4470 ctx = perf_event_ctx_lock(event);
4471 ret = __perf_read(event, buf, count);
4472 perf_event_ctx_unlock(event, ctx);
4477 static unsigned int perf_poll(struct file *file, poll_table *wait)
4479 struct perf_event *event = file->private_data;
4480 struct ring_buffer *rb;
4481 unsigned int events = POLLHUP;
4483 poll_wait(file, &event->waitq, wait);
4485 if (is_event_hup(event))
4489 * Pin the event->rb by taking event->mmap_mutex; otherwise
4490 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4492 mutex_lock(&event->mmap_mutex);
4495 events = atomic_xchg(&rb->poll, 0);
4496 mutex_unlock(&event->mmap_mutex);
4500 static void _perf_event_reset(struct perf_event *event)
4502 (void)perf_event_read(event, false);
4503 local64_set(&event->count, 0);
4504 perf_event_update_userpage(event);
4508 * Holding the top-level event's child_mutex means that any
4509 * descendant process that has inherited this event will block
4510 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4511 * task existence requirements of perf_event_enable/disable.
4513 static void perf_event_for_each_child(struct perf_event *event,
4514 void (*func)(struct perf_event *))
4516 struct perf_event *child;
4518 WARN_ON_ONCE(event->ctx->parent_ctx);
4520 mutex_lock(&event->child_mutex);
4522 list_for_each_entry(child, &event->child_list, child_list)
4524 mutex_unlock(&event->child_mutex);
4527 static void perf_event_for_each(struct perf_event *event,
4528 void (*func)(struct perf_event *))
4530 struct perf_event_context *ctx = event->ctx;
4531 struct perf_event *sibling;
4533 lockdep_assert_held(&ctx->mutex);
4535 event = event->group_leader;
4537 perf_event_for_each_child(event, func);
4538 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4539 perf_event_for_each_child(sibling, func);
4542 static void __perf_event_period(struct perf_event *event,
4543 struct perf_cpu_context *cpuctx,
4544 struct perf_event_context *ctx,
4547 u64 value = *((u64 *)info);
4550 if (event->attr.freq) {
4551 event->attr.sample_freq = value;
4553 event->attr.sample_period = value;
4554 event->hw.sample_period = value;
4557 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4559 perf_pmu_disable(ctx->pmu);
4561 * We could be throttled; unthrottle now to avoid the tick
4562 * trying to unthrottle while we already re-started the event.
4564 if (event->hw.interrupts == MAX_INTERRUPTS) {
4565 event->hw.interrupts = 0;
4566 perf_log_throttle(event, 1);
4568 event->pmu->stop(event, PERF_EF_UPDATE);
4571 local64_set(&event->hw.period_left, 0);
4574 event->pmu->start(event, PERF_EF_RELOAD);
4575 perf_pmu_enable(ctx->pmu);
4579 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4583 if (!is_sampling_event(event))
4586 if (copy_from_user(&value, arg, sizeof(value)))
4592 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4595 event_function_call(event, __perf_event_period, &value);
4600 static const struct file_operations perf_fops;
4602 static inline int perf_fget_light(int fd, struct fd *p)
4604 struct fd f = fdget(fd);
4608 if (f.file->f_op != &perf_fops) {
4616 static int perf_event_set_output(struct perf_event *event,
4617 struct perf_event *output_event);
4618 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4619 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4621 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4623 void (*func)(struct perf_event *);
4627 case PERF_EVENT_IOC_ENABLE:
4628 func = _perf_event_enable;
4630 case PERF_EVENT_IOC_DISABLE:
4631 func = _perf_event_disable;
4633 case PERF_EVENT_IOC_RESET:
4634 func = _perf_event_reset;
4637 case PERF_EVENT_IOC_REFRESH:
4638 return _perf_event_refresh(event, arg);
4640 case PERF_EVENT_IOC_PERIOD:
4641 return perf_event_period(event, (u64 __user *)arg);
4643 case PERF_EVENT_IOC_ID:
4645 u64 id = primary_event_id(event);
4647 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4652 case PERF_EVENT_IOC_SET_OUTPUT:
4656 struct perf_event *output_event;
4658 ret = perf_fget_light(arg, &output);
4661 output_event = output.file->private_data;
4662 ret = perf_event_set_output(event, output_event);
4665 ret = perf_event_set_output(event, NULL);
4670 case PERF_EVENT_IOC_SET_FILTER:
4671 return perf_event_set_filter(event, (void __user *)arg);
4673 case PERF_EVENT_IOC_SET_BPF:
4674 return perf_event_set_bpf_prog(event, arg);
4676 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4677 struct ring_buffer *rb;
4680 rb = rcu_dereference(event->rb);
4681 if (!rb || !rb->nr_pages) {
4685 rb_toggle_paused(rb, !!arg);
4693 if (flags & PERF_IOC_FLAG_GROUP)
4694 perf_event_for_each(event, func);
4696 perf_event_for_each_child(event, func);
4701 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4703 struct perf_event *event = file->private_data;
4704 struct perf_event_context *ctx;
4707 ctx = perf_event_ctx_lock(event);
4708 ret = _perf_ioctl(event, cmd, arg);
4709 perf_event_ctx_unlock(event, ctx);
4714 #ifdef CONFIG_COMPAT
4715 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4718 switch (_IOC_NR(cmd)) {
4719 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4720 case _IOC_NR(PERF_EVENT_IOC_ID):
4721 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4722 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4723 cmd &= ~IOCSIZE_MASK;
4724 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4728 return perf_ioctl(file, cmd, arg);
4731 # define perf_compat_ioctl NULL
4734 int perf_event_task_enable(void)
4736 struct perf_event_context *ctx;
4737 struct perf_event *event;
4739 mutex_lock(¤t->perf_event_mutex);
4740 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4741 ctx = perf_event_ctx_lock(event);
4742 perf_event_for_each_child(event, _perf_event_enable);
4743 perf_event_ctx_unlock(event, ctx);
4745 mutex_unlock(¤t->perf_event_mutex);
4750 int perf_event_task_disable(void)
4752 struct perf_event_context *ctx;
4753 struct perf_event *event;
4755 mutex_lock(¤t->perf_event_mutex);
4756 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4757 ctx = perf_event_ctx_lock(event);
4758 perf_event_for_each_child(event, _perf_event_disable);
4759 perf_event_ctx_unlock(event, ctx);
4761 mutex_unlock(¤t->perf_event_mutex);
4766 static int perf_event_index(struct perf_event *event)
4768 if (event->hw.state & PERF_HES_STOPPED)
4771 if (event->state != PERF_EVENT_STATE_ACTIVE)
4774 return event->pmu->event_idx(event);
4777 static void calc_timer_values(struct perf_event *event,
4784 *now = perf_clock();
4785 ctx_time = event->shadow_ctx_time + *now;
4786 *enabled = ctx_time - event->tstamp_enabled;
4787 *running = ctx_time - event->tstamp_running;
4790 static void perf_event_init_userpage(struct perf_event *event)
4792 struct perf_event_mmap_page *userpg;
4793 struct ring_buffer *rb;
4796 rb = rcu_dereference(event->rb);
4800 userpg = rb->user_page;
4802 /* Allow new userspace to detect that bit 0 is deprecated */
4803 userpg->cap_bit0_is_deprecated = 1;
4804 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4805 userpg->data_offset = PAGE_SIZE;
4806 userpg->data_size = perf_data_size(rb);
4812 void __weak arch_perf_update_userpage(
4813 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4818 * Callers need to ensure there can be no nesting of this function, otherwise
4819 * the seqlock logic goes bad. We can not serialize this because the arch
4820 * code calls this from NMI context.
4822 void perf_event_update_userpage(struct perf_event *event)
4824 struct perf_event_mmap_page *userpg;
4825 struct ring_buffer *rb;
4826 u64 enabled, running, now;
4829 rb = rcu_dereference(event->rb);
4834 * compute total_time_enabled, total_time_running
4835 * based on snapshot values taken when the event
4836 * was last scheduled in.
4838 * we cannot simply called update_context_time()
4839 * because of locking issue as we can be called in
4842 calc_timer_values(event, &now, &enabled, &running);
4844 userpg = rb->user_page;
4846 * Disable preemption so as to not let the corresponding user-space
4847 * spin too long if we get preempted.
4852 userpg->index = perf_event_index(event);
4853 userpg->offset = perf_event_count(event);
4855 userpg->offset -= local64_read(&event->hw.prev_count);
4857 userpg->time_enabled = enabled +
4858 atomic64_read(&event->child_total_time_enabled);
4860 userpg->time_running = running +
4861 atomic64_read(&event->child_total_time_running);
4863 arch_perf_update_userpage(event, userpg, now);
4872 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4874 struct perf_event *event = vma->vm_file->private_data;
4875 struct ring_buffer *rb;
4876 int ret = VM_FAULT_SIGBUS;
4878 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4879 if (vmf->pgoff == 0)
4885 rb = rcu_dereference(event->rb);
4889 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4892 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4896 get_page(vmf->page);
4897 vmf->page->mapping = vma->vm_file->f_mapping;
4898 vmf->page->index = vmf->pgoff;
4907 static void ring_buffer_attach(struct perf_event *event,
4908 struct ring_buffer *rb)
4910 struct ring_buffer *old_rb = NULL;
4911 unsigned long flags;
4915 * Should be impossible, we set this when removing
4916 * event->rb_entry and wait/clear when adding event->rb_entry.
4918 WARN_ON_ONCE(event->rcu_pending);
4921 spin_lock_irqsave(&old_rb->event_lock, flags);
4922 list_del_rcu(&event->rb_entry);
4923 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4925 event->rcu_batches = get_state_synchronize_rcu();
4926 event->rcu_pending = 1;
4930 if (event->rcu_pending) {
4931 cond_synchronize_rcu(event->rcu_batches);
4932 event->rcu_pending = 0;
4935 spin_lock_irqsave(&rb->event_lock, flags);
4936 list_add_rcu(&event->rb_entry, &rb->event_list);
4937 spin_unlock_irqrestore(&rb->event_lock, flags);
4941 * Avoid racing with perf_mmap_close(AUX): stop the event
4942 * before swizzling the event::rb pointer; if it's getting
4943 * unmapped, its aux_mmap_count will be 0 and it won't
4944 * restart. See the comment in __perf_pmu_output_stop().
4946 * Data will inevitably be lost when set_output is done in
4947 * mid-air, but then again, whoever does it like this is
4948 * not in for the data anyway.
4951 perf_event_stop(event, 0);
4953 rcu_assign_pointer(event->rb, rb);
4956 ring_buffer_put(old_rb);
4958 * Since we detached before setting the new rb, so that we
4959 * could attach the new rb, we could have missed a wakeup.
4962 wake_up_all(&event->waitq);
4966 static void ring_buffer_wakeup(struct perf_event *event)
4968 struct ring_buffer *rb;
4971 rb = rcu_dereference(event->rb);
4973 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4974 wake_up_all(&event->waitq);
4979 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4981 struct ring_buffer *rb;
4984 rb = rcu_dereference(event->rb);
4986 if (!atomic_inc_not_zero(&rb->refcount))
4994 void ring_buffer_put(struct ring_buffer *rb)
4996 if (!atomic_dec_and_test(&rb->refcount))
4999 WARN_ON_ONCE(!list_empty(&rb->event_list));
5001 call_rcu(&rb->rcu_head, rb_free_rcu);
5004 static void perf_mmap_open(struct vm_area_struct *vma)
5006 struct perf_event *event = vma->vm_file->private_data;
5008 atomic_inc(&event->mmap_count);
5009 atomic_inc(&event->rb->mmap_count);
5012 atomic_inc(&event->rb->aux_mmap_count);
5014 if (event->pmu->event_mapped)
5015 event->pmu->event_mapped(event);
5018 static void perf_pmu_output_stop(struct perf_event *event);
5021 * A buffer can be mmap()ed multiple times; either directly through the same
5022 * event, or through other events by use of perf_event_set_output().
5024 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5025 * the buffer here, where we still have a VM context. This means we need
5026 * to detach all events redirecting to us.
5028 static void perf_mmap_close(struct vm_area_struct *vma)
5030 struct perf_event *event = vma->vm_file->private_data;
5032 struct ring_buffer *rb = ring_buffer_get(event);
5033 struct user_struct *mmap_user = rb->mmap_user;
5034 int mmap_locked = rb->mmap_locked;
5035 unsigned long size = perf_data_size(rb);
5037 if (event->pmu->event_unmapped)
5038 event->pmu->event_unmapped(event);
5041 * rb->aux_mmap_count will always drop before rb->mmap_count and
5042 * event->mmap_count, so it is ok to use event->mmap_mutex to
5043 * serialize with perf_mmap here.
5045 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5046 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5048 * Stop all AUX events that are writing to this buffer,
5049 * so that we can free its AUX pages and corresponding PMU
5050 * data. Note that after rb::aux_mmap_count dropped to zero,
5051 * they won't start any more (see perf_aux_output_begin()).
5053 perf_pmu_output_stop(event);
5055 /* now it's safe to free the pages */
5056 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5057 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5059 /* this has to be the last one */
5061 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5063 mutex_unlock(&event->mmap_mutex);
5066 atomic_dec(&rb->mmap_count);
5068 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5071 ring_buffer_attach(event, NULL);
5072 mutex_unlock(&event->mmap_mutex);
5074 /* If there's still other mmap()s of this buffer, we're done. */
5075 if (atomic_read(&rb->mmap_count))
5079 * No other mmap()s, detach from all other events that might redirect
5080 * into the now unreachable buffer. Somewhat complicated by the
5081 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5085 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5086 if (!atomic_long_inc_not_zero(&event->refcount)) {
5088 * This event is en-route to free_event() which will
5089 * detach it and remove it from the list.
5095 mutex_lock(&event->mmap_mutex);
5097 * Check we didn't race with perf_event_set_output() which can
5098 * swizzle the rb from under us while we were waiting to
5099 * acquire mmap_mutex.
5101 * If we find a different rb; ignore this event, a next
5102 * iteration will no longer find it on the list. We have to
5103 * still restart the iteration to make sure we're not now
5104 * iterating the wrong list.
5106 if (event->rb == rb)
5107 ring_buffer_attach(event, NULL);
5109 mutex_unlock(&event->mmap_mutex);
5113 * Restart the iteration; either we're on the wrong list or
5114 * destroyed its integrity by doing a deletion.
5121 * It could be there's still a few 0-ref events on the list; they'll
5122 * get cleaned up by free_event() -- they'll also still have their
5123 * ref on the rb and will free it whenever they are done with it.
5125 * Aside from that, this buffer is 'fully' detached and unmapped,
5126 * undo the VM accounting.
5129 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5130 vma->vm_mm->pinned_vm -= mmap_locked;
5131 free_uid(mmap_user);
5134 ring_buffer_put(rb); /* could be last */
5137 static const struct vm_operations_struct perf_mmap_vmops = {
5138 .open = perf_mmap_open,
5139 .close = perf_mmap_close, /* non mergable */
5140 .fault = perf_mmap_fault,
5141 .page_mkwrite = perf_mmap_fault,
5144 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5146 struct perf_event *event = file->private_data;
5147 unsigned long user_locked, user_lock_limit;
5148 struct user_struct *user = current_user();
5149 unsigned long locked, lock_limit;
5150 struct ring_buffer *rb = NULL;
5151 unsigned long vma_size;
5152 unsigned long nr_pages;
5153 long user_extra = 0, extra = 0;
5154 int ret = 0, flags = 0;
5157 * Don't allow mmap() of inherited per-task counters. This would
5158 * create a performance issue due to all children writing to the
5161 if (event->cpu == -1 && event->attr.inherit)
5164 if (!(vma->vm_flags & VM_SHARED))
5167 vma_size = vma->vm_end - vma->vm_start;
5169 if (vma->vm_pgoff == 0) {
5170 nr_pages = (vma_size / PAGE_SIZE) - 1;
5173 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5174 * mapped, all subsequent mappings should have the same size
5175 * and offset. Must be above the normal perf buffer.
5177 u64 aux_offset, aux_size;
5182 nr_pages = vma_size / PAGE_SIZE;
5184 mutex_lock(&event->mmap_mutex);
5191 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5192 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5194 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5197 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5200 /* already mapped with a different offset */
5201 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5204 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5207 /* already mapped with a different size */
5208 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5211 if (!is_power_of_2(nr_pages))
5214 if (!atomic_inc_not_zero(&rb->mmap_count))
5217 if (rb_has_aux(rb)) {
5218 atomic_inc(&rb->aux_mmap_count);
5223 atomic_set(&rb->aux_mmap_count, 1);
5224 user_extra = nr_pages;
5230 * If we have rb pages ensure they're a power-of-two number, so we
5231 * can do bitmasks instead of modulo.
5233 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5236 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5239 WARN_ON_ONCE(event->ctx->parent_ctx);
5241 mutex_lock(&event->mmap_mutex);
5243 if (event->rb->nr_pages != nr_pages) {
5248 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5250 * Raced against perf_mmap_close() through
5251 * perf_event_set_output(). Try again, hope for better
5254 mutex_unlock(&event->mmap_mutex);
5261 user_extra = nr_pages + 1;
5264 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5267 * Increase the limit linearly with more CPUs:
5269 user_lock_limit *= num_online_cpus();
5271 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5273 if (user_locked > user_lock_limit)
5274 extra = user_locked - user_lock_limit;
5276 lock_limit = rlimit(RLIMIT_MEMLOCK);
5277 lock_limit >>= PAGE_SHIFT;
5278 locked = vma->vm_mm->pinned_vm + extra;
5280 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5281 !capable(CAP_IPC_LOCK)) {
5286 WARN_ON(!rb && event->rb);
5288 if (vma->vm_flags & VM_WRITE)
5289 flags |= RING_BUFFER_WRITABLE;
5292 rb = rb_alloc(nr_pages,
5293 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5301 atomic_set(&rb->mmap_count, 1);
5302 rb->mmap_user = get_current_user();
5303 rb->mmap_locked = extra;
5305 ring_buffer_attach(event, rb);
5307 perf_event_init_userpage(event);
5308 perf_event_update_userpage(event);
5310 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5311 event->attr.aux_watermark, flags);
5313 rb->aux_mmap_locked = extra;
5318 atomic_long_add(user_extra, &user->locked_vm);
5319 vma->vm_mm->pinned_vm += extra;
5321 atomic_inc(&event->mmap_count);
5323 atomic_dec(&rb->mmap_count);
5326 mutex_unlock(&event->mmap_mutex);
5329 * Since pinned accounting is per vm we cannot allow fork() to copy our
5332 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5333 vma->vm_ops = &perf_mmap_vmops;
5335 if (event->pmu->event_mapped)
5336 event->pmu->event_mapped(event);
5341 static int perf_fasync(int fd, struct file *filp, int on)
5343 struct inode *inode = file_inode(filp);
5344 struct perf_event *event = filp->private_data;
5348 retval = fasync_helper(fd, filp, on, &event->fasync);
5349 inode_unlock(inode);
5357 static const struct file_operations perf_fops = {
5358 .llseek = no_llseek,
5359 .release = perf_release,
5362 .unlocked_ioctl = perf_ioctl,
5363 .compat_ioctl = perf_compat_ioctl,
5365 .fasync = perf_fasync,
5371 * If there's data, ensure we set the poll() state and publish everything
5372 * to user-space before waking everybody up.
5375 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5377 /* only the parent has fasync state */
5379 event = event->parent;
5380 return &event->fasync;
5383 void perf_event_wakeup(struct perf_event *event)
5385 ring_buffer_wakeup(event);
5387 if (event->pending_kill) {
5388 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5389 event->pending_kill = 0;
5393 static void perf_pending_event(struct irq_work *entry)
5395 struct perf_event *event = container_of(entry,
5396 struct perf_event, pending);
5399 rctx = perf_swevent_get_recursion_context();
5401 * If we 'fail' here, that's OK, it means recursion is already disabled
5402 * and we won't recurse 'further'.
5405 if (event->pending_disable) {
5406 event->pending_disable = 0;
5407 perf_event_disable_local(event);
5410 if (event->pending_wakeup) {
5411 event->pending_wakeup = 0;
5412 perf_event_wakeup(event);
5416 perf_swevent_put_recursion_context(rctx);
5420 * We assume there is only KVM supporting the callbacks.
5421 * Later on, we might change it to a list if there is
5422 * another virtualization implementation supporting the callbacks.
5424 struct perf_guest_info_callbacks *perf_guest_cbs;
5426 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5428 perf_guest_cbs = cbs;
5431 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5433 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5435 perf_guest_cbs = NULL;
5438 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5441 perf_output_sample_regs(struct perf_output_handle *handle,
5442 struct pt_regs *regs, u64 mask)
5445 DECLARE_BITMAP(_mask, 64);
5447 bitmap_from_u64(_mask, mask);
5448 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5451 val = perf_reg_value(regs, bit);
5452 perf_output_put(handle, val);
5456 static void perf_sample_regs_user(struct perf_regs *regs_user,
5457 struct pt_regs *regs,
5458 struct pt_regs *regs_user_copy)
5460 if (user_mode(regs)) {
5461 regs_user->abi = perf_reg_abi(current);
5462 regs_user->regs = regs;
5463 } else if (current->mm) {
5464 perf_get_regs_user(regs_user, regs, regs_user_copy);
5466 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5467 regs_user->regs = NULL;
5471 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5472 struct pt_regs *regs)
5474 regs_intr->regs = regs;
5475 regs_intr->abi = perf_reg_abi(current);
5480 * Get remaining task size from user stack pointer.
5482 * It'd be better to take stack vma map and limit this more
5483 * precisly, but there's no way to get it safely under interrupt,
5484 * so using TASK_SIZE as limit.
5486 static u64 perf_ustack_task_size(struct pt_regs *regs)
5488 unsigned long addr = perf_user_stack_pointer(regs);
5490 if (!addr || addr >= TASK_SIZE)
5493 return TASK_SIZE - addr;
5497 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5498 struct pt_regs *regs)
5502 /* No regs, no stack pointer, no dump. */
5507 * Check if we fit in with the requested stack size into the:
5509 * If we don't, we limit the size to the TASK_SIZE.
5511 * - remaining sample size
5512 * If we don't, we customize the stack size to
5513 * fit in to the remaining sample size.
5516 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5517 stack_size = min(stack_size, (u16) task_size);
5519 /* Current header size plus static size and dynamic size. */
5520 header_size += 2 * sizeof(u64);
5522 /* Do we fit in with the current stack dump size? */
5523 if ((u16) (header_size + stack_size) < header_size) {
5525 * If we overflow the maximum size for the sample,
5526 * we customize the stack dump size to fit in.
5528 stack_size = USHRT_MAX - header_size - sizeof(u64);
5529 stack_size = round_up(stack_size, sizeof(u64));
5536 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5537 struct pt_regs *regs)
5539 /* Case of a kernel thread, nothing to dump */
5542 perf_output_put(handle, size);
5551 * - the size requested by user or the best one we can fit
5552 * in to the sample max size
5554 * - user stack dump data
5556 * - the actual dumped size
5560 perf_output_put(handle, dump_size);
5563 sp = perf_user_stack_pointer(regs);
5564 rem = __output_copy_user(handle, (void *) sp, dump_size);
5565 dyn_size = dump_size - rem;
5567 perf_output_skip(handle, rem);
5570 perf_output_put(handle, dyn_size);
5574 static void __perf_event_header__init_id(struct perf_event_header *header,
5575 struct perf_sample_data *data,
5576 struct perf_event *event)
5578 u64 sample_type = event->attr.sample_type;
5580 data->type = sample_type;
5581 header->size += event->id_header_size;
5583 if (sample_type & PERF_SAMPLE_TID) {
5584 /* namespace issues */
5585 data->tid_entry.pid = perf_event_pid(event, current);
5586 data->tid_entry.tid = perf_event_tid(event, current);
5589 if (sample_type & PERF_SAMPLE_TIME)
5590 data->time = perf_event_clock(event);
5592 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5593 data->id = primary_event_id(event);
5595 if (sample_type & PERF_SAMPLE_STREAM_ID)
5596 data->stream_id = event->id;
5598 if (sample_type & PERF_SAMPLE_CPU) {
5599 data->cpu_entry.cpu = raw_smp_processor_id();
5600 data->cpu_entry.reserved = 0;
5604 void perf_event_header__init_id(struct perf_event_header *header,
5605 struct perf_sample_data *data,
5606 struct perf_event *event)
5608 if (event->attr.sample_id_all)
5609 __perf_event_header__init_id(header, data, event);
5612 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5613 struct perf_sample_data *data)
5615 u64 sample_type = data->type;
5617 if (sample_type & PERF_SAMPLE_TID)
5618 perf_output_put(handle, data->tid_entry);
5620 if (sample_type & PERF_SAMPLE_TIME)
5621 perf_output_put(handle, data->time);
5623 if (sample_type & PERF_SAMPLE_ID)
5624 perf_output_put(handle, data->id);
5626 if (sample_type & PERF_SAMPLE_STREAM_ID)
5627 perf_output_put(handle, data->stream_id);
5629 if (sample_type & PERF_SAMPLE_CPU)
5630 perf_output_put(handle, data->cpu_entry);
5632 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5633 perf_output_put(handle, data->id);
5636 void perf_event__output_id_sample(struct perf_event *event,
5637 struct perf_output_handle *handle,
5638 struct perf_sample_data *sample)
5640 if (event->attr.sample_id_all)
5641 __perf_event__output_id_sample(handle, sample);
5644 static void perf_output_read_one(struct perf_output_handle *handle,
5645 struct perf_event *event,
5646 u64 enabled, u64 running)
5648 u64 read_format = event->attr.read_format;
5652 values[n++] = perf_event_count(event);
5653 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5654 values[n++] = enabled +
5655 atomic64_read(&event->child_total_time_enabled);
5657 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5658 values[n++] = running +
5659 atomic64_read(&event->child_total_time_running);
5661 if (read_format & PERF_FORMAT_ID)
5662 values[n++] = primary_event_id(event);
5664 __output_copy(handle, values, n * sizeof(u64));
5668 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5670 static void perf_output_read_group(struct perf_output_handle *handle,
5671 struct perf_event *event,
5672 u64 enabled, u64 running)
5674 struct perf_event *leader = event->group_leader, *sub;
5675 u64 read_format = event->attr.read_format;
5679 values[n++] = 1 + leader->nr_siblings;
5681 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5682 values[n++] = enabled;
5684 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5685 values[n++] = running;
5687 if (leader != event)
5688 leader->pmu->read(leader);
5690 values[n++] = perf_event_count(leader);
5691 if (read_format & PERF_FORMAT_ID)
5692 values[n++] = primary_event_id(leader);
5694 __output_copy(handle, values, n * sizeof(u64));
5696 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5699 if ((sub != event) &&
5700 (sub->state == PERF_EVENT_STATE_ACTIVE))
5701 sub->pmu->read(sub);
5703 values[n++] = perf_event_count(sub);
5704 if (read_format & PERF_FORMAT_ID)
5705 values[n++] = primary_event_id(sub);
5707 __output_copy(handle, values, n * sizeof(u64));
5711 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5712 PERF_FORMAT_TOTAL_TIME_RUNNING)
5714 static void perf_output_read(struct perf_output_handle *handle,
5715 struct perf_event *event)
5717 u64 enabled = 0, running = 0, now;
5718 u64 read_format = event->attr.read_format;
5721 * compute total_time_enabled, total_time_running
5722 * based on snapshot values taken when the event
5723 * was last scheduled in.
5725 * we cannot simply called update_context_time()
5726 * because of locking issue as we are called in
5729 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5730 calc_timer_values(event, &now, &enabled, &running);
5732 if (event->attr.read_format & PERF_FORMAT_GROUP)
5733 perf_output_read_group(handle, event, enabled, running);
5735 perf_output_read_one(handle, event, enabled, running);
5738 void perf_output_sample(struct perf_output_handle *handle,
5739 struct perf_event_header *header,
5740 struct perf_sample_data *data,
5741 struct perf_event *event)
5743 u64 sample_type = data->type;
5745 perf_output_put(handle, *header);
5747 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5748 perf_output_put(handle, data->id);
5750 if (sample_type & PERF_SAMPLE_IP)
5751 perf_output_put(handle, data->ip);
5753 if (sample_type & PERF_SAMPLE_TID)
5754 perf_output_put(handle, data->tid_entry);
5756 if (sample_type & PERF_SAMPLE_TIME)
5757 perf_output_put(handle, data->time);
5759 if (sample_type & PERF_SAMPLE_ADDR)
5760 perf_output_put(handle, data->addr);
5762 if (sample_type & PERF_SAMPLE_ID)
5763 perf_output_put(handle, data->id);
5765 if (sample_type & PERF_SAMPLE_STREAM_ID)
5766 perf_output_put(handle, data->stream_id);
5768 if (sample_type & PERF_SAMPLE_CPU)
5769 perf_output_put(handle, data->cpu_entry);
5771 if (sample_type & PERF_SAMPLE_PERIOD)
5772 perf_output_put(handle, data->period);
5774 if (sample_type & PERF_SAMPLE_READ)
5775 perf_output_read(handle, event);
5777 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5778 if (data->callchain) {
5781 if (data->callchain)
5782 size += data->callchain->nr;
5784 size *= sizeof(u64);
5786 __output_copy(handle, data->callchain, size);
5789 perf_output_put(handle, nr);
5793 if (sample_type & PERF_SAMPLE_RAW) {
5794 struct perf_raw_record *raw = data->raw;
5797 struct perf_raw_frag *frag = &raw->frag;
5799 perf_output_put(handle, raw->size);
5802 __output_custom(handle, frag->copy,
5803 frag->data, frag->size);
5805 __output_copy(handle, frag->data,
5808 if (perf_raw_frag_last(frag))
5813 __output_skip(handle, NULL, frag->pad);
5819 .size = sizeof(u32),
5822 perf_output_put(handle, raw);
5826 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5827 if (data->br_stack) {
5830 size = data->br_stack->nr
5831 * sizeof(struct perf_branch_entry);
5833 perf_output_put(handle, data->br_stack->nr);
5834 perf_output_copy(handle, data->br_stack->entries, size);
5837 * we always store at least the value of nr
5840 perf_output_put(handle, nr);
5844 if (sample_type & PERF_SAMPLE_REGS_USER) {
5845 u64 abi = data->regs_user.abi;
5848 * If there are no regs to dump, notice it through
5849 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5851 perf_output_put(handle, abi);
5854 u64 mask = event->attr.sample_regs_user;
5855 perf_output_sample_regs(handle,
5856 data->regs_user.regs,
5861 if (sample_type & PERF_SAMPLE_STACK_USER) {
5862 perf_output_sample_ustack(handle,
5863 data->stack_user_size,
5864 data->regs_user.regs);
5867 if (sample_type & PERF_SAMPLE_WEIGHT)
5868 perf_output_put(handle, data->weight);
5870 if (sample_type & PERF_SAMPLE_DATA_SRC)
5871 perf_output_put(handle, data->data_src.val);
5873 if (sample_type & PERF_SAMPLE_TRANSACTION)
5874 perf_output_put(handle, data->txn);
5876 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5877 u64 abi = data->regs_intr.abi;
5879 * If there are no regs to dump, notice it through
5880 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5882 perf_output_put(handle, abi);
5885 u64 mask = event->attr.sample_regs_intr;
5887 perf_output_sample_regs(handle,
5888 data->regs_intr.regs,
5893 if (!event->attr.watermark) {
5894 int wakeup_events = event->attr.wakeup_events;
5896 if (wakeup_events) {
5897 struct ring_buffer *rb = handle->rb;
5898 int events = local_inc_return(&rb->events);
5900 if (events >= wakeup_events) {
5901 local_sub(wakeup_events, &rb->events);
5902 local_inc(&rb->wakeup);
5908 void perf_prepare_sample(struct perf_event_header *header,
5909 struct perf_sample_data *data,
5910 struct perf_event *event,
5911 struct pt_regs *regs)
5913 u64 sample_type = event->attr.sample_type;
5915 header->type = PERF_RECORD_SAMPLE;
5916 header->size = sizeof(*header) + event->header_size;
5919 header->misc |= perf_misc_flags(regs);
5921 __perf_event_header__init_id(header, data, event);
5923 if (sample_type & PERF_SAMPLE_IP)
5924 data->ip = perf_instruction_pointer(regs);
5926 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5929 data->callchain = perf_callchain(event, regs);
5931 if (data->callchain)
5932 size += data->callchain->nr;
5934 header->size += size * sizeof(u64);
5937 if (sample_type & PERF_SAMPLE_RAW) {
5938 struct perf_raw_record *raw = data->raw;
5942 struct perf_raw_frag *frag = &raw->frag;
5947 if (perf_raw_frag_last(frag))
5952 size = round_up(sum + sizeof(u32), sizeof(u64));
5953 raw->size = size - sizeof(u32);
5954 frag->pad = raw->size - sum;
5959 header->size += size;
5962 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5963 int size = sizeof(u64); /* nr */
5964 if (data->br_stack) {
5965 size += data->br_stack->nr
5966 * sizeof(struct perf_branch_entry);
5968 header->size += size;
5971 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5972 perf_sample_regs_user(&data->regs_user, regs,
5973 &data->regs_user_copy);
5975 if (sample_type & PERF_SAMPLE_REGS_USER) {
5976 /* regs dump ABI info */
5977 int size = sizeof(u64);
5979 if (data->regs_user.regs) {
5980 u64 mask = event->attr.sample_regs_user;
5981 size += hweight64(mask) * sizeof(u64);
5984 header->size += size;
5987 if (sample_type & PERF_SAMPLE_STACK_USER) {
5989 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5990 * processed as the last one or have additional check added
5991 * in case new sample type is added, because we could eat
5992 * up the rest of the sample size.
5994 u16 stack_size = event->attr.sample_stack_user;
5995 u16 size = sizeof(u64);
5997 stack_size = perf_sample_ustack_size(stack_size, header->size,
5998 data->regs_user.regs);
6001 * If there is something to dump, add space for the dump
6002 * itself and for the field that tells the dynamic size,
6003 * which is how many have been actually dumped.
6006 size += sizeof(u64) + stack_size;
6008 data->stack_user_size = stack_size;
6009 header->size += size;
6012 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6013 /* regs dump ABI info */
6014 int size = sizeof(u64);
6016 perf_sample_regs_intr(&data->regs_intr, regs);
6018 if (data->regs_intr.regs) {
6019 u64 mask = event->attr.sample_regs_intr;
6021 size += hweight64(mask) * sizeof(u64);
6024 header->size += size;
6028 static void __always_inline
6029 __perf_event_output(struct perf_event *event,
6030 struct perf_sample_data *data,
6031 struct pt_regs *regs,
6032 int (*output_begin)(struct perf_output_handle *,
6033 struct perf_event *,
6036 struct perf_output_handle handle;
6037 struct perf_event_header header;
6039 /* protect the callchain buffers */
6042 perf_prepare_sample(&header, data, event, regs);
6044 if (output_begin(&handle, event, header.size))
6047 perf_output_sample(&handle, &header, data, event);
6049 perf_output_end(&handle);
6056 perf_event_output_forward(struct perf_event *event,
6057 struct perf_sample_data *data,
6058 struct pt_regs *regs)
6060 __perf_event_output(event, data, regs, perf_output_begin_forward);
6064 perf_event_output_backward(struct perf_event *event,
6065 struct perf_sample_data *data,
6066 struct pt_regs *regs)
6068 __perf_event_output(event, data, regs, perf_output_begin_backward);
6072 perf_event_output(struct perf_event *event,
6073 struct perf_sample_data *data,
6074 struct pt_regs *regs)
6076 __perf_event_output(event, data, regs, perf_output_begin);
6083 struct perf_read_event {
6084 struct perf_event_header header;
6091 perf_event_read_event(struct perf_event *event,
6092 struct task_struct *task)
6094 struct perf_output_handle handle;
6095 struct perf_sample_data sample;
6096 struct perf_read_event read_event = {
6098 .type = PERF_RECORD_READ,
6100 .size = sizeof(read_event) + event->read_size,
6102 .pid = perf_event_pid(event, task),
6103 .tid = perf_event_tid(event, task),
6107 perf_event_header__init_id(&read_event.header, &sample, event);
6108 ret = perf_output_begin(&handle, event, read_event.header.size);
6112 perf_output_put(&handle, read_event);
6113 perf_output_read(&handle, event);
6114 perf_event__output_id_sample(event, &handle, &sample);
6116 perf_output_end(&handle);
6119 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6122 perf_iterate_ctx(struct perf_event_context *ctx,
6123 perf_iterate_f output,
6124 void *data, bool all)
6126 struct perf_event *event;
6128 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6130 if (event->state < PERF_EVENT_STATE_INACTIVE)
6132 if (!event_filter_match(event))
6136 output(event, data);
6140 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6142 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6143 struct perf_event *event;
6145 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6147 * Skip events that are not fully formed yet; ensure that
6148 * if we observe event->ctx, both event and ctx will be
6149 * complete enough. See perf_install_in_context().
6151 if (!smp_load_acquire(&event->ctx))
6154 if (event->state < PERF_EVENT_STATE_INACTIVE)
6156 if (!event_filter_match(event))
6158 output(event, data);
6163 * Iterate all events that need to receive side-band events.
6165 * For new callers; ensure that account_pmu_sb_event() includes
6166 * your event, otherwise it might not get delivered.
6169 perf_iterate_sb(perf_iterate_f output, void *data,
6170 struct perf_event_context *task_ctx)
6172 struct perf_event_context *ctx;
6179 * If we have task_ctx != NULL we only notify the task context itself.
6180 * The task_ctx is set only for EXIT events before releasing task
6184 perf_iterate_ctx(task_ctx, output, data, false);
6188 perf_iterate_sb_cpu(output, data);
6190 for_each_task_context_nr(ctxn) {
6191 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6193 perf_iterate_ctx(ctx, output, data, false);
6201 * Clear all file-based filters at exec, they'll have to be
6202 * re-instated when/if these objects are mmapped again.
6204 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6206 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6207 struct perf_addr_filter *filter;
6208 unsigned int restart = 0, count = 0;
6209 unsigned long flags;
6211 if (!has_addr_filter(event))
6214 raw_spin_lock_irqsave(&ifh->lock, flags);
6215 list_for_each_entry(filter, &ifh->list, entry) {
6216 if (filter->inode) {
6217 event->addr_filters_offs[count] = 0;
6225 event->addr_filters_gen++;
6226 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6229 perf_event_stop(event, 1);
6232 void perf_event_exec(void)
6234 struct perf_event_context *ctx;
6238 for_each_task_context_nr(ctxn) {
6239 ctx = current->perf_event_ctxp[ctxn];
6243 perf_event_enable_on_exec(ctxn);
6245 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6251 struct remote_output {
6252 struct ring_buffer *rb;
6256 static void __perf_event_output_stop(struct perf_event *event, void *data)
6258 struct perf_event *parent = event->parent;
6259 struct remote_output *ro = data;
6260 struct ring_buffer *rb = ro->rb;
6261 struct stop_event_data sd = {
6265 if (!has_aux(event))
6272 * In case of inheritance, it will be the parent that links to the
6273 * ring-buffer, but it will be the child that's actually using it.
6275 * We are using event::rb to determine if the event should be stopped,
6276 * however this may race with ring_buffer_attach() (through set_output),
6277 * which will make us skip the event that actually needs to be stopped.
6278 * So ring_buffer_attach() has to stop an aux event before re-assigning
6281 if (rcu_dereference(parent->rb) == rb)
6282 ro->err = __perf_event_stop(&sd);
6285 static int __perf_pmu_output_stop(void *info)
6287 struct perf_event *event = info;
6288 struct pmu *pmu = event->pmu;
6289 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6290 struct remote_output ro = {
6295 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6296 if (cpuctx->task_ctx)
6297 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6304 static void perf_pmu_output_stop(struct perf_event *event)
6306 struct perf_event *iter;
6311 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6313 * For per-CPU events, we need to make sure that neither they
6314 * nor their children are running; for cpu==-1 events it's
6315 * sufficient to stop the event itself if it's active, since
6316 * it can't have children.
6320 cpu = READ_ONCE(iter->oncpu);
6325 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6326 if (err == -EAGAIN) {
6335 * task tracking -- fork/exit
6337 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6340 struct perf_task_event {
6341 struct task_struct *task;
6342 struct perf_event_context *task_ctx;
6345 struct perf_event_header header;
6355 static int perf_event_task_match(struct perf_event *event)
6357 return event->attr.comm || event->attr.mmap ||
6358 event->attr.mmap2 || event->attr.mmap_data ||
6362 static void perf_event_task_output(struct perf_event *event,
6365 struct perf_task_event *task_event = data;
6366 struct perf_output_handle handle;
6367 struct perf_sample_data sample;
6368 struct task_struct *task = task_event->task;
6369 int ret, size = task_event->event_id.header.size;
6371 if (!perf_event_task_match(event))
6374 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6376 ret = perf_output_begin(&handle, event,
6377 task_event->event_id.header.size);
6381 task_event->event_id.pid = perf_event_pid(event, task);
6382 task_event->event_id.ppid = perf_event_pid(event, current);
6384 task_event->event_id.tid = perf_event_tid(event, task);
6385 task_event->event_id.ptid = perf_event_tid(event, current);
6387 task_event->event_id.time = perf_event_clock(event);
6389 perf_output_put(&handle, task_event->event_id);
6391 perf_event__output_id_sample(event, &handle, &sample);
6393 perf_output_end(&handle);
6395 task_event->event_id.header.size = size;
6398 static void perf_event_task(struct task_struct *task,
6399 struct perf_event_context *task_ctx,
6402 struct perf_task_event task_event;
6404 if (!atomic_read(&nr_comm_events) &&
6405 !atomic_read(&nr_mmap_events) &&
6406 !atomic_read(&nr_task_events))
6409 task_event = (struct perf_task_event){
6411 .task_ctx = task_ctx,
6414 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6416 .size = sizeof(task_event.event_id),
6426 perf_iterate_sb(perf_event_task_output,
6431 void perf_event_fork(struct task_struct *task)
6433 perf_event_task(task, NULL, 1);
6440 struct perf_comm_event {
6441 struct task_struct *task;
6446 struct perf_event_header header;
6453 static int perf_event_comm_match(struct perf_event *event)
6455 return event->attr.comm;
6458 static void perf_event_comm_output(struct perf_event *event,
6461 struct perf_comm_event *comm_event = data;
6462 struct perf_output_handle handle;
6463 struct perf_sample_data sample;
6464 int size = comm_event->event_id.header.size;
6467 if (!perf_event_comm_match(event))
6470 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6471 ret = perf_output_begin(&handle, event,
6472 comm_event->event_id.header.size);
6477 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6478 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6480 perf_output_put(&handle, comm_event->event_id);
6481 __output_copy(&handle, comm_event->comm,
6482 comm_event->comm_size);
6484 perf_event__output_id_sample(event, &handle, &sample);
6486 perf_output_end(&handle);
6488 comm_event->event_id.header.size = size;
6491 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6493 char comm[TASK_COMM_LEN];
6496 memset(comm, 0, sizeof(comm));
6497 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6498 size = ALIGN(strlen(comm)+1, sizeof(u64));
6500 comm_event->comm = comm;
6501 comm_event->comm_size = size;
6503 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6505 perf_iterate_sb(perf_event_comm_output,
6510 void perf_event_comm(struct task_struct *task, bool exec)
6512 struct perf_comm_event comm_event;
6514 if (!atomic_read(&nr_comm_events))
6517 comm_event = (struct perf_comm_event){
6523 .type = PERF_RECORD_COMM,
6524 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6532 perf_event_comm_event(&comm_event);
6539 struct perf_mmap_event {
6540 struct vm_area_struct *vma;
6542 const char *file_name;
6550 struct perf_event_header header;
6560 static int perf_event_mmap_match(struct perf_event *event,
6563 struct perf_mmap_event *mmap_event = data;
6564 struct vm_area_struct *vma = mmap_event->vma;
6565 int executable = vma->vm_flags & VM_EXEC;
6567 return (!executable && event->attr.mmap_data) ||
6568 (executable && (event->attr.mmap || event->attr.mmap2));
6571 static void perf_event_mmap_output(struct perf_event *event,
6574 struct perf_mmap_event *mmap_event = data;
6575 struct perf_output_handle handle;
6576 struct perf_sample_data sample;
6577 int size = mmap_event->event_id.header.size;
6580 if (!perf_event_mmap_match(event, data))
6583 if (event->attr.mmap2) {
6584 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6585 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6586 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6587 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6588 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6589 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6590 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6593 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6594 ret = perf_output_begin(&handle, event,
6595 mmap_event->event_id.header.size);
6599 mmap_event->event_id.pid = perf_event_pid(event, current);
6600 mmap_event->event_id.tid = perf_event_tid(event, current);
6602 perf_output_put(&handle, mmap_event->event_id);
6604 if (event->attr.mmap2) {
6605 perf_output_put(&handle, mmap_event->maj);
6606 perf_output_put(&handle, mmap_event->min);
6607 perf_output_put(&handle, mmap_event->ino);
6608 perf_output_put(&handle, mmap_event->ino_generation);
6609 perf_output_put(&handle, mmap_event->prot);
6610 perf_output_put(&handle, mmap_event->flags);
6613 __output_copy(&handle, mmap_event->file_name,
6614 mmap_event->file_size);
6616 perf_event__output_id_sample(event, &handle, &sample);
6618 perf_output_end(&handle);
6620 mmap_event->event_id.header.size = size;
6623 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6625 struct vm_area_struct *vma = mmap_event->vma;
6626 struct file *file = vma->vm_file;
6627 int maj = 0, min = 0;
6628 u64 ino = 0, gen = 0;
6629 u32 prot = 0, flags = 0;
6635 if (vma->vm_flags & VM_READ)
6637 if (vma->vm_flags & VM_WRITE)
6639 if (vma->vm_flags & VM_EXEC)
6642 if (vma->vm_flags & VM_MAYSHARE)
6645 flags = MAP_PRIVATE;
6647 if (vma->vm_flags & VM_DENYWRITE)
6648 flags |= MAP_DENYWRITE;
6649 if (vma->vm_flags & VM_MAYEXEC)
6650 flags |= MAP_EXECUTABLE;
6651 if (vma->vm_flags & VM_LOCKED)
6652 flags |= MAP_LOCKED;
6653 if (vma->vm_flags & VM_HUGETLB)
6654 flags |= MAP_HUGETLB;
6657 struct inode *inode;
6660 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6666 * d_path() works from the end of the rb backwards, so we
6667 * need to add enough zero bytes after the string to handle
6668 * the 64bit alignment we do later.
6670 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6675 inode = file_inode(vma->vm_file);
6676 dev = inode->i_sb->s_dev;
6678 gen = inode->i_generation;
6684 if (vma->vm_ops && vma->vm_ops->name) {
6685 name = (char *) vma->vm_ops->name(vma);
6690 name = (char *)arch_vma_name(vma);
6694 if (vma->vm_start <= vma->vm_mm->start_brk &&
6695 vma->vm_end >= vma->vm_mm->brk) {
6699 if (vma->vm_start <= vma->vm_mm->start_stack &&
6700 vma->vm_end >= vma->vm_mm->start_stack) {
6710 strlcpy(tmp, name, sizeof(tmp));
6714 * Since our buffer works in 8 byte units we need to align our string
6715 * size to a multiple of 8. However, we must guarantee the tail end is
6716 * zero'd out to avoid leaking random bits to userspace.
6718 size = strlen(name)+1;
6719 while (!IS_ALIGNED(size, sizeof(u64)))
6720 name[size++] = '\0';
6722 mmap_event->file_name = name;
6723 mmap_event->file_size = size;
6724 mmap_event->maj = maj;
6725 mmap_event->min = min;
6726 mmap_event->ino = ino;
6727 mmap_event->ino_generation = gen;
6728 mmap_event->prot = prot;
6729 mmap_event->flags = flags;
6731 if (!(vma->vm_flags & VM_EXEC))
6732 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6734 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6736 perf_iterate_sb(perf_event_mmap_output,
6744 * Check whether inode and address range match filter criteria.
6746 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6747 struct file *file, unsigned long offset,
6750 if (filter->inode != file_inode(file))
6753 if (filter->offset > offset + size)
6756 if (filter->offset + filter->size < offset)
6762 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6764 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6765 struct vm_area_struct *vma = data;
6766 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6767 struct file *file = vma->vm_file;
6768 struct perf_addr_filter *filter;
6769 unsigned int restart = 0, count = 0;
6771 if (!has_addr_filter(event))
6777 raw_spin_lock_irqsave(&ifh->lock, flags);
6778 list_for_each_entry(filter, &ifh->list, entry) {
6779 if (perf_addr_filter_match(filter, file, off,
6780 vma->vm_end - vma->vm_start)) {
6781 event->addr_filters_offs[count] = vma->vm_start;
6789 event->addr_filters_gen++;
6790 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6793 perf_event_stop(event, 1);
6797 * Adjust all task's events' filters to the new vma
6799 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6801 struct perf_event_context *ctx;
6805 * Data tracing isn't supported yet and as such there is no need
6806 * to keep track of anything that isn't related to executable code:
6808 if (!(vma->vm_flags & VM_EXEC))
6812 for_each_task_context_nr(ctxn) {
6813 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6817 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6822 void perf_event_mmap(struct vm_area_struct *vma)
6824 struct perf_mmap_event mmap_event;
6826 if (!atomic_read(&nr_mmap_events))
6829 mmap_event = (struct perf_mmap_event){
6835 .type = PERF_RECORD_MMAP,
6836 .misc = PERF_RECORD_MISC_USER,
6841 .start = vma->vm_start,
6842 .len = vma->vm_end - vma->vm_start,
6843 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6845 /* .maj (attr_mmap2 only) */
6846 /* .min (attr_mmap2 only) */
6847 /* .ino (attr_mmap2 only) */
6848 /* .ino_generation (attr_mmap2 only) */
6849 /* .prot (attr_mmap2 only) */
6850 /* .flags (attr_mmap2 only) */
6853 perf_addr_filters_adjust(vma);
6854 perf_event_mmap_event(&mmap_event);
6857 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6858 unsigned long size, u64 flags)
6860 struct perf_output_handle handle;
6861 struct perf_sample_data sample;
6862 struct perf_aux_event {
6863 struct perf_event_header header;
6869 .type = PERF_RECORD_AUX,
6871 .size = sizeof(rec),
6879 perf_event_header__init_id(&rec.header, &sample, event);
6880 ret = perf_output_begin(&handle, event, rec.header.size);
6885 perf_output_put(&handle, rec);
6886 perf_event__output_id_sample(event, &handle, &sample);
6888 perf_output_end(&handle);
6892 * Lost/dropped samples logging
6894 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6896 struct perf_output_handle handle;
6897 struct perf_sample_data sample;
6901 struct perf_event_header header;
6903 } lost_samples_event = {
6905 .type = PERF_RECORD_LOST_SAMPLES,
6907 .size = sizeof(lost_samples_event),
6912 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6914 ret = perf_output_begin(&handle, event,
6915 lost_samples_event.header.size);
6919 perf_output_put(&handle, lost_samples_event);
6920 perf_event__output_id_sample(event, &handle, &sample);
6921 perf_output_end(&handle);
6925 * context_switch tracking
6928 struct perf_switch_event {
6929 struct task_struct *task;
6930 struct task_struct *next_prev;
6933 struct perf_event_header header;
6939 static int perf_event_switch_match(struct perf_event *event)
6941 return event->attr.context_switch;
6944 static void perf_event_switch_output(struct perf_event *event, void *data)
6946 struct perf_switch_event *se = data;
6947 struct perf_output_handle handle;
6948 struct perf_sample_data sample;
6951 if (!perf_event_switch_match(event))
6954 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6955 if (event->ctx->task) {
6956 se->event_id.header.type = PERF_RECORD_SWITCH;
6957 se->event_id.header.size = sizeof(se->event_id.header);
6959 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6960 se->event_id.header.size = sizeof(se->event_id);
6961 se->event_id.next_prev_pid =
6962 perf_event_pid(event, se->next_prev);
6963 se->event_id.next_prev_tid =
6964 perf_event_tid(event, se->next_prev);
6967 perf_event_header__init_id(&se->event_id.header, &sample, event);
6969 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6973 if (event->ctx->task)
6974 perf_output_put(&handle, se->event_id.header);
6976 perf_output_put(&handle, se->event_id);
6978 perf_event__output_id_sample(event, &handle, &sample);
6980 perf_output_end(&handle);
6983 static void perf_event_switch(struct task_struct *task,
6984 struct task_struct *next_prev, bool sched_in)
6986 struct perf_switch_event switch_event;
6988 /* N.B. caller checks nr_switch_events != 0 */
6990 switch_event = (struct perf_switch_event){
6992 .next_prev = next_prev,
6996 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6999 /* .next_prev_pid */
7000 /* .next_prev_tid */
7004 perf_iterate_sb(perf_event_switch_output,
7010 * IRQ throttle logging
7013 static void perf_log_throttle(struct perf_event *event, int enable)
7015 struct perf_output_handle handle;
7016 struct perf_sample_data sample;
7020 struct perf_event_header header;
7024 } throttle_event = {
7026 .type = PERF_RECORD_THROTTLE,
7028 .size = sizeof(throttle_event),
7030 .time = perf_event_clock(event),
7031 .id = primary_event_id(event),
7032 .stream_id = event->id,
7036 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7038 perf_event_header__init_id(&throttle_event.header, &sample, event);
7040 ret = perf_output_begin(&handle, event,
7041 throttle_event.header.size);
7045 perf_output_put(&handle, throttle_event);
7046 perf_event__output_id_sample(event, &handle, &sample);
7047 perf_output_end(&handle);
7050 static void perf_log_itrace_start(struct perf_event *event)
7052 struct perf_output_handle handle;
7053 struct perf_sample_data sample;
7054 struct perf_aux_event {
7055 struct perf_event_header header;
7062 event = event->parent;
7064 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7065 event->hw.itrace_started)
7068 rec.header.type = PERF_RECORD_ITRACE_START;
7069 rec.header.misc = 0;
7070 rec.header.size = sizeof(rec);
7071 rec.pid = perf_event_pid(event, current);
7072 rec.tid = perf_event_tid(event, current);
7074 perf_event_header__init_id(&rec.header, &sample, event);
7075 ret = perf_output_begin(&handle, event, rec.header.size);
7080 perf_output_put(&handle, rec);
7081 perf_event__output_id_sample(event, &handle, &sample);
7083 perf_output_end(&handle);
7087 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7089 struct hw_perf_event *hwc = &event->hw;
7093 seq = __this_cpu_read(perf_throttled_seq);
7094 if (seq != hwc->interrupts_seq) {
7095 hwc->interrupts_seq = seq;
7096 hwc->interrupts = 1;
7099 if (unlikely(throttle
7100 && hwc->interrupts >= max_samples_per_tick)) {
7101 __this_cpu_inc(perf_throttled_count);
7102 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7103 hwc->interrupts = MAX_INTERRUPTS;
7104 perf_log_throttle(event, 0);
7109 if (event->attr.freq) {
7110 u64 now = perf_clock();
7111 s64 delta = now - hwc->freq_time_stamp;
7113 hwc->freq_time_stamp = now;
7115 if (delta > 0 && delta < 2*TICK_NSEC)
7116 perf_adjust_period(event, delta, hwc->last_period, true);
7122 int perf_event_account_interrupt(struct perf_event *event)
7124 return __perf_event_account_interrupt(event, 1);
7128 * Generic event overflow handling, sampling.
7131 static int __perf_event_overflow(struct perf_event *event,
7132 int throttle, struct perf_sample_data *data,
7133 struct pt_regs *regs)
7135 int events = atomic_read(&event->event_limit);
7139 * Non-sampling counters might still use the PMI to fold short
7140 * hardware counters, ignore those.
7142 if (unlikely(!is_sampling_event(event)))
7145 ret = __perf_event_account_interrupt(event, throttle);
7148 * XXX event_limit might not quite work as expected on inherited
7152 event->pending_kill = POLL_IN;
7153 if (events && atomic_dec_and_test(&event->event_limit)) {
7155 event->pending_kill = POLL_HUP;
7157 perf_event_disable_inatomic(event);
7160 READ_ONCE(event->overflow_handler)(event, data, regs);
7162 if (*perf_event_fasync(event) && event->pending_kill) {
7163 event->pending_wakeup = 1;
7164 irq_work_queue(&event->pending);
7170 int perf_event_overflow(struct perf_event *event,
7171 struct perf_sample_data *data,
7172 struct pt_regs *regs)
7174 return __perf_event_overflow(event, 1, data, regs);
7178 * Generic software event infrastructure
7181 struct swevent_htable {
7182 struct swevent_hlist *swevent_hlist;
7183 struct mutex hlist_mutex;
7186 /* Recursion avoidance in each contexts */
7187 int recursion[PERF_NR_CONTEXTS];
7190 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7193 * We directly increment event->count and keep a second value in
7194 * event->hw.period_left to count intervals. This period event
7195 * is kept in the range [-sample_period, 0] so that we can use the
7199 u64 perf_swevent_set_period(struct perf_event *event)
7201 struct hw_perf_event *hwc = &event->hw;
7202 u64 period = hwc->last_period;
7206 hwc->last_period = hwc->sample_period;
7209 old = val = local64_read(&hwc->period_left);
7213 nr = div64_u64(period + val, period);
7214 offset = nr * period;
7216 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7222 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7223 struct perf_sample_data *data,
7224 struct pt_regs *regs)
7226 struct hw_perf_event *hwc = &event->hw;
7230 overflow = perf_swevent_set_period(event);
7232 if (hwc->interrupts == MAX_INTERRUPTS)
7235 for (; overflow; overflow--) {
7236 if (__perf_event_overflow(event, throttle,
7239 * We inhibit the overflow from happening when
7240 * hwc->interrupts == MAX_INTERRUPTS.
7248 static void perf_swevent_event(struct perf_event *event, u64 nr,
7249 struct perf_sample_data *data,
7250 struct pt_regs *regs)
7252 struct hw_perf_event *hwc = &event->hw;
7254 local64_add(nr, &event->count);
7259 if (!is_sampling_event(event))
7262 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7264 return perf_swevent_overflow(event, 1, data, regs);
7266 data->period = event->hw.last_period;
7268 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7269 return perf_swevent_overflow(event, 1, data, regs);
7271 if (local64_add_negative(nr, &hwc->period_left))
7274 perf_swevent_overflow(event, 0, data, regs);
7277 static int perf_exclude_event(struct perf_event *event,
7278 struct pt_regs *regs)
7280 if (event->hw.state & PERF_HES_STOPPED)
7284 if (event->attr.exclude_user && user_mode(regs))
7287 if (event->attr.exclude_kernel && !user_mode(regs))
7294 static int perf_swevent_match(struct perf_event *event,
7295 enum perf_type_id type,
7297 struct perf_sample_data *data,
7298 struct pt_regs *regs)
7300 if (event->attr.type != type)
7303 if (event->attr.config != event_id)
7306 if (perf_exclude_event(event, regs))
7312 static inline u64 swevent_hash(u64 type, u32 event_id)
7314 u64 val = event_id | (type << 32);
7316 return hash_64(val, SWEVENT_HLIST_BITS);
7319 static inline struct hlist_head *
7320 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7322 u64 hash = swevent_hash(type, event_id);
7324 return &hlist->heads[hash];
7327 /* For the read side: events when they trigger */
7328 static inline struct hlist_head *
7329 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7331 struct swevent_hlist *hlist;
7333 hlist = rcu_dereference(swhash->swevent_hlist);
7337 return __find_swevent_head(hlist, type, event_id);
7340 /* For the event head insertion and removal in the hlist */
7341 static inline struct hlist_head *
7342 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7344 struct swevent_hlist *hlist;
7345 u32 event_id = event->attr.config;
7346 u64 type = event->attr.type;
7349 * Event scheduling is always serialized against hlist allocation
7350 * and release. Which makes the protected version suitable here.
7351 * The context lock guarantees that.
7353 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7354 lockdep_is_held(&event->ctx->lock));
7358 return __find_swevent_head(hlist, type, event_id);
7361 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7363 struct perf_sample_data *data,
7364 struct pt_regs *regs)
7366 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7367 struct perf_event *event;
7368 struct hlist_head *head;
7371 head = find_swevent_head_rcu(swhash, type, event_id);
7375 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7376 if (perf_swevent_match(event, type, event_id, data, regs))
7377 perf_swevent_event(event, nr, data, regs);
7383 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7385 int perf_swevent_get_recursion_context(void)
7387 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7389 return get_recursion_context(swhash->recursion);
7391 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7393 void perf_swevent_put_recursion_context(int rctx)
7395 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7397 put_recursion_context(swhash->recursion, rctx);
7400 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7402 struct perf_sample_data data;
7404 if (WARN_ON_ONCE(!regs))
7407 perf_sample_data_init(&data, addr, 0);
7408 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7411 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7415 preempt_disable_notrace();
7416 rctx = perf_swevent_get_recursion_context();
7417 if (unlikely(rctx < 0))
7420 ___perf_sw_event(event_id, nr, regs, addr);
7422 perf_swevent_put_recursion_context(rctx);
7424 preempt_enable_notrace();
7427 static void perf_swevent_read(struct perf_event *event)
7431 static int perf_swevent_add(struct perf_event *event, int flags)
7433 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7434 struct hw_perf_event *hwc = &event->hw;
7435 struct hlist_head *head;
7437 if (is_sampling_event(event)) {
7438 hwc->last_period = hwc->sample_period;
7439 perf_swevent_set_period(event);
7442 hwc->state = !(flags & PERF_EF_START);
7444 head = find_swevent_head(swhash, event);
7445 if (WARN_ON_ONCE(!head))
7448 hlist_add_head_rcu(&event->hlist_entry, head);
7449 perf_event_update_userpage(event);
7454 static void perf_swevent_del(struct perf_event *event, int flags)
7456 hlist_del_rcu(&event->hlist_entry);
7459 static void perf_swevent_start(struct perf_event *event, int flags)
7461 event->hw.state = 0;
7464 static void perf_swevent_stop(struct perf_event *event, int flags)
7466 event->hw.state = PERF_HES_STOPPED;
7469 /* Deref the hlist from the update side */
7470 static inline struct swevent_hlist *
7471 swevent_hlist_deref(struct swevent_htable *swhash)
7473 return rcu_dereference_protected(swhash->swevent_hlist,
7474 lockdep_is_held(&swhash->hlist_mutex));
7477 static void swevent_hlist_release(struct swevent_htable *swhash)
7479 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7484 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7485 kfree_rcu(hlist, rcu_head);
7488 static void swevent_hlist_put_cpu(int cpu)
7490 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7492 mutex_lock(&swhash->hlist_mutex);
7494 if (!--swhash->hlist_refcount)
7495 swevent_hlist_release(swhash);
7497 mutex_unlock(&swhash->hlist_mutex);
7500 static void swevent_hlist_put(void)
7504 for_each_possible_cpu(cpu)
7505 swevent_hlist_put_cpu(cpu);
7508 static int swevent_hlist_get_cpu(int cpu)
7510 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7513 mutex_lock(&swhash->hlist_mutex);
7514 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7515 struct swevent_hlist *hlist;
7517 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7522 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7524 swhash->hlist_refcount++;
7526 mutex_unlock(&swhash->hlist_mutex);
7531 static int swevent_hlist_get(void)
7533 int err, cpu, failed_cpu;
7536 for_each_possible_cpu(cpu) {
7537 err = swevent_hlist_get_cpu(cpu);
7547 for_each_possible_cpu(cpu) {
7548 if (cpu == failed_cpu)
7550 swevent_hlist_put_cpu(cpu);
7557 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7559 static void sw_perf_event_destroy(struct perf_event *event)
7561 u64 event_id = event->attr.config;
7563 WARN_ON(event->parent);
7565 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7566 swevent_hlist_put();
7569 static int perf_swevent_init(struct perf_event *event)
7571 u64 event_id = event->attr.config;
7573 if (event->attr.type != PERF_TYPE_SOFTWARE)
7577 * no branch sampling for software events
7579 if (has_branch_stack(event))
7583 case PERF_COUNT_SW_CPU_CLOCK:
7584 case PERF_COUNT_SW_TASK_CLOCK:
7591 if (event_id >= PERF_COUNT_SW_MAX)
7594 if (!event->parent) {
7597 err = swevent_hlist_get();
7601 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7602 event->destroy = sw_perf_event_destroy;
7608 static struct pmu perf_swevent = {
7609 .task_ctx_nr = perf_sw_context,
7611 .capabilities = PERF_PMU_CAP_NO_NMI,
7613 .event_init = perf_swevent_init,
7614 .add = perf_swevent_add,
7615 .del = perf_swevent_del,
7616 .start = perf_swevent_start,
7617 .stop = perf_swevent_stop,
7618 .read = perf_swevent_read,
7621 #ifdef CONFIG_EVENT_TRACING
7623 static int perf_tp_filter_match(struct perf_event *event,
7624 struct perf_sample_data *data)
7626 void *record = data->raw->frag.data;
7628 /* only top level events have filters set */
7630 event = event->parent;
7632 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7637 static int perf_tp_event_match(struct perf_event *event,
7638 struct perf_sample_data *data,
7639 struct pt_regs *regs)
7641 if (event->hw.state & PERF_HES_STOPPED)
7644 * All tracepoints are from kernel-space.
7646 if (event->attr.exclude_kernel)
7649 if (!perf_tp_filter_match(event, data))
7655 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7656 struct trace_event_call *call, u64 count,
7657 struct pt_regs *regs, struct hlist_head *head,
7658 struct task_struct *task)
7660 struct bpf_prog *prog = call->prog;
7663 *(struct pt_regs **)raw_data = regs;
7664 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7665 perf_swevent_put_recursion_context(rctx);
7669 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7672 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7674 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7675 struct pt_regs *regs, struct hlist_head *head, int rctx,
7676 struct task_struct *task)
7678 struct perf_sample_data data;
7679 struct perf_event *event;
7681 struct perf_raw_record raw = {
7688 perf_sample_data_init(&data, 0, 0);
7691 perf_trace_buf_update(record, event_type);
7693 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7694 if (perf_tp_event_match(event, &data, regs))
7695 perf_swevent_event(event, count, &data, regs);
7699 * If we got specified a target task, also iterate its context and
7700 * deliver this event there too.
7702 if (task && task != current) {
7703 struct perf_event_context *ctx;
7704 struct trace_entry *entry = record;
7707 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7711 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7712 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7714 if (event->attr.config != entry->type)
7716 if (perf_tp_event_match(event, &data, regs))
7717 perf_swevent_event(event, count, &data, regs);
7723 perf_swevent_put_recursion_context(rctx);
7725 EXPORT_SYMBOL_GPL(perf_tp_event);
7727 static void tp_perf_event_destroy(struct perf_event *event)
7729 perf_trace_destroy(event);
7732 static int perf_tp_event_init(struct perf_event *event)
7736 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7740 * no branch sampling for tracepoint events
7742 if (has_branch_stack(event))
7745 err = perf_trace_init(event);
7749 event->destroy = tp_perf_event_destroy;
7754 static struct pmu perf_tracepoint = {
7755 .task_ctx_nr = perf_sw_context,
7757 .event_init = perf_tp_event_init,
7758 .add = perf_trace_add,
7759 .del = perf_trace_del,
7760 .start = perf_swevent_start,
7761 .stop = perf_swevent_stop,
7762 .read = perf_swevent_read,
7765 static inline void perf_tp_register(void)
7767 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7770 static void perf_event_free_filter(struct perf_event *event)
7772 ftrace_profile_free_filter(event);
7775 #ifdef CONFIG_BPF_SYSCALL
7776 static void bpf_overflow_handler(struct perf_event *event,
7777 struct perf_sample_data *data,
7778 struct pt_regs *regs)
7780 struct bpf_perf_event_data_kern ctx = {
7787 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7790 ret = BPF_PROG_RUN(event->prog, &ctx);
7793 __this_cpu_dec(bpf_prog_active);
7798 event->orig_overflow_handler(event, data, regs);
7801 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7803 struct bpf_prog *prog;
7805 if (event->overflow_handler_context)
7806 /* hw breakpoint or kernel counter */
7812 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
7814 return PTR_ERR(prog);
7817 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
7818 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
7822 static void perf_event_free_bpf_handler(struct perf_event *event)
7824 struct bpf_prog *prog = event->prog;
7829 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
7834 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7838 static void perf_event_free_bpf_handler(struct perf_event *event)
7843 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7845 bool is_kprobe, is_tracepoint;
7846 struct bpf_prog *prog;
7848 if (event->attr.type == PERF_TYPE_HARDWARE ||
7849 event->attr.type == PERF_TYPE_SOFTWARE)
7850 return perf_event_set_bpf_handler(event, prog_fd);
7852 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7855 if (event->tp_event->prog)
7858 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7859 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7860 if (!is_kprobe && !is_tracepoint)
7861 /* bpf programs can only be attached to u/kprobe or tracepoint */
7864 prog = bpf_prog_get(prog_fd);
7866 return PTR_ERR(prog);
7868 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7869 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7870 /* valid fd, but invalid bpf program type */
7875 if (is_tracepoint) {
7876 int off = trace_event_get_offsets(event->tp_event);
7878 if (prog->aux->max_ctx_offset > off) {
7883 event->tp_event->prog = prog;
7888 static void perf_event_free_bpf_prog(struct perf_event *event)
7890 struct bpf_prog *prog;
7892 perf_event_free_bpf_handler(event);
7894 if (!event->tp_event)
7897 prog = event->tp_event->prog;
7899 event->tp_event->prog = NULL;
7906 static inline void perf_tp_register(void)
7910 static void perf_event_free_filter(struct perf_event *event)
7914 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7919 static void perf_event_free_bpf_prog(struct perf_event *event)
7922 #endif /* CONFIG_EVENT_TRACING */
7924 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7925 void perf_bp_event(struct perf_event *bp, void *data)
7927 struct perf_sample_data sample;
7928 struct pt_regs *regs = data;
7930 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7932 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7933 perf_swevent_event(bp, 1, &sample, regs);
7938 * Allocate a new address filter
7940 static struct perf_addr_filter *
7941 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7943 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7944 struct perf_addr_filter *filter;
7946 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7950 INIT_LIST_HEAD(&filter->entry);
7951 list_add_tail(&filter->entry, filters);
7956 static void free_filters_list(struct list_head *filters)
7958 struct perf_addr_filter *filter, *iter;
7960 list_for_each_entry_safe(filter, iter, filters, entry) {
7962 iput(filter->inode);
7963 list_del(&filter->entry);
7969 * Free existing address filters and optionally install new ones
7971 static void perf_addr_filters_splice(struct perf_event *event,
7972 struct list_head *head)
7974 unsigned long flags;
7977 if (!has_addr_filter(event))
7980 /* don't bother with children, they don't have their own filters */
7984 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7986 list_splice_init(&event->addr_filters.list, &list);
7988 list_splice(head, &event->addr_filters.list);
7990 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7992 free_filters_list(&list);
7996 * Scan through mm's vmas and see if one of them matches the
7997 * @filter; if so, adjust filter's address range.
7998 * Called with mm::mmap_sem down for reading.
8000 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8001 struct mm_struct *mm)
8003 struct vm_area_struct *vma;
8005 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8006 struct file *file = vma->vm_file;
8007 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8008 unsigned long vma_size = vma->vm_end - vma->vm_start;
8013 if (!perf_addr_filter_match(filter, file, off, vma_size))
8016 return vma->vm_start;
8023 * Update event's address range filters based on the
8024 * task's existing mappings, if any.
8026 static void perf_event_addr_filters_apply(struct perf_event *event)
8028 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8029 struct task_struct *task = READ_ONCE(event->ctx->task);
8030 struct perf_addr_filter *filter;
8031 struct mm_struct *mm = NULL;
8032 unsigned int count = 0;
8033 unsigned long flags;
8036 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8037 * will stop on the parent's child_mutex that our caller is also holding
8039 if (task == TASK_TOMBSTONE)
8042 mm = get_task_mm(event->ctx->task);
8046 down_read(&mm->mmap_sem);
8048 raw_spin_lock_irqsave(&ifh->lock, flags);
8049 list_for_each_entry(filter, &ifh->list, entry) {
8050 event->addr_filters_offs[count] = 0;
8053 * Adjust base offset if the filter is associated to a binary
8054 * that needs to be mapped:
8057 event->addr_filters_offs[count] =
8058 perf_addr_filter_apply(filter, mm);
8063 event->addr_filters_gen++;
8064 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8066 up_read(&mm->mmap_sem);
8071 perf_event_stop(event, 1);
8075 * Address range filtering: limiting the data to certain
8076 * instruction address ranges. Filters are ioctl()ed to us from
8077 * userspace as ascii strings.
8079 * Filter string format:
8082 * where ACTION is one of the
8083 * * "filter": limit the trace to this region
8084 * * "start": start tracing from this address
8085 * * "stop": stop tracing at this address/region;
8087 * * for kernel addresses: <start address>[/<size>]
8088 * * for object files: <start address>[/<size>]@</path/to/object/file>
8090 * if <size> is not specified, the range is treated as a single address.
8104 IF_STATE_ACTION = 0,
8109 static const match_table_t if_tokens = {
8110 { IF_ACT_FILTER, "filter" },
8111 { IF_ACT_START, "start" },
8112 { IF_ACT_STOP, "stop" },
8113 { IF_SRC_FILE, "%u/%u@%s" },
8114 { IF_SRC_KERNEL, "%u/%u" },
8115 { IF_SRC_FILEADDR, "%u@%s" },
8116 { IF_SRC_KERNELADDR, "%u" },
8117 { IF_ACT_NONE, NULL },
8121 * Address filter string parser
8124 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8125 struct list_head *filters)
8127 struct perf_addr_filter *filter = NULL;
8128 char *start, *orig, *filename = NULL;
8130 substring_t args[MAX_OPT_ARGS];
8131 int state = IF_STATE_ACTION, token;
8132 unsigned int kernel = 0;
8135 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8139 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8145 /* filter definition begins */
8146 if (state == IF_STATE_ACTION) {
8147 filter = perf_addr_filter_new(event, filters);
8152 token = match_token(start, if_tokens, args);
8159 if (state != IF_STATE_ACTION)
8162 state = IF_STATE_SOURCE;
8165 case IF_SRC_KERNELADDR:
8169 case IF_SRC_FILEADDR:
8171 if (state != IF_STATE_SOURCE)
8174 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8178 ret = kstrtoul(args[0].from, 0, &filter->offset);
8182 if (filter->range) {
8184 ret = kstrtoul(args[1].from, 0, &filter->size);
8189 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8190 int fpos = filter->range ? 2 : 1;
8192 filename = match_strdup(&args[fpos]);
8199 state = IF_STATE_END;
8207 * Filter definition is fully parsed, validate and install it.
8208 * Make sure that it doesn't contradict itself or the event's
8211 if (state == IF_STATE_END) {
8212 if (kernel && event->attr.exclude_kernel)
8219 /* look up the path and grab its inode */
8220 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8222 goto fail_free_name;
8224 filter->inode = igrab(d_inode(path.dentry));
8230 if (!filter->inode ||
8231 !S_ISREG(filter->inode->i_mode))
8232 /* free_filters_list() will iput() */
8236 /* ready to consume more filters */
8237 state = IF_STATE_ACTION;
8242 if (state != IF_STATE_ACTION)
8252 free_filters_list(filters);
8259 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8265 * Since this is called in perf_ioctl() path, we're already holding
8268 lockdep_assert_held(&event->ctx->mutex);
8270 if (WARN_ON_ONCE(event->parent))
8274 * For now, we only support filtering in per-task events; doing so
8275 * for CPU-wide events requires additional context switching trickery,
8276 * since same object code will be mapped at different virtual
8277 * addresses in different processes.
8279 if (!event->ctx->task)
8282 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8286 ret = event->pmu->addr_filters_validate(&filters);
8288 free_filters_list(&filters);
8292 /* remove existing filters, if any */
8293 perf_addr_filters_splice(event, &filters);
8295 /* install new filters */
8296 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8301 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8306 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8307 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8308 !has_addr_filter(event))
8311 filter_str = strndup_user(arg, PAGE_SIZE);
8312 if (IS_ERR(filter_str))
8313 return PTR_ERR(filter_str);
8315 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8316 event->attr.type == PERF_TYPE_TRACEPOINT)
8317 ret = ftrace_profile_set_filter(event, event->attr.config,
8319 else if (has_addr_filter(event))
8320 ret = perf_event_set_addr_filter(event, filter_str);
8327 * hrtimer based swevent callback
8330 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8332 enum hrtimer_restart ret = HRTIMER_RESTART;
8333 struct perf_sample_data data;
8334 struct pt_regs *regs;
8335 struct perf_event *event;
8338 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8340 if (event->state != PERF_EVENT_STATE_ACTIVE)
8341 return HRTIMER_NORESTART;
8343 event->pmu->read(event);
8345 perf_sample_data_init(&data, 0, event->hw.last_period);
8346 regs = get_irq_regs();
8348 if (regs && !perf_exclude_event(event, regs)) {
8349 if (!(event->attr.exclude_idle && is_idle_task(current)))
8350 if (__perf_event_overflow(event, 1, &data, regs))
8351 ret = HRTIMER_NORESTART;
8354 period = max_t(u64, 10000, event->hw.sample_period);
8355 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8360 static void perf_swevent_start_hrtimer(struct perf_event *event)
8362 struct hw_perf_event *hwc = &event->hw;
8365 if (!is_sampling_event(event))
8368 period = local64_read(&hwc->period_left);
8373 local64_set(&hwc->period_left, 0);
8375 period = max_t(u64, 10000, hwc->sample_period);
8377 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8378 HRTIMER_MODE_REL_PINNED);
8381 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8383 struct hw_perf_event *hwc = &event->hw;
8385 if (is_sampling_event(event)) {
8386 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8387 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8389 hrtimer_cancel(&hwc->hrtimer);
8393 static void perf_swevent_init_hrtimer(struct perf_event *event)
8395 struct hw_perf_event *hwc = &event->hw;
8397 if (!is_sampling_event(event))
8400 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8401 hwc->hrtimer.function = perf_swevent_hrtimer;
8404 * Since hrtimers have a fixed rate, we can do a static freq->period
8405 * mapping and avoid the whole period adjust feedback stuff.
8407 if (event->attr.freq) {
8408 long freq = event->attr.sample_freq;
8410 event->attr.sample_period = NSEC_PER_SEC / freq;
8411 hwc->sample_period = event->attr.sample_period;
8412 local64_set(&hwc->period_left, hwc->sample_period);
8413 hwc->last_period = hwc->sample_period;
8414 event->attr.freq = 0;
8419 * Software event: cpu wall time clock
8422 static void cpu_clock_event_update(struct perf_event *event)
8427 now = local_clock();
8428 prev = local64_xchg(&event->hw.prev_count, now);
8429 local64_add(now - prev, &event->count);
8432 static void cpu_clock_event_start(struct perf_event *event, int flags)
8434 local64_set(&event->hw.prev_count, local_clock());
8435 perf_swevent_start_hrtimer(event);
8438 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8440 perf_swevent_cancel_hrtimer(event);
8441 cpu_clock_event_update(event);
8444 static int cpu_clock_event_add(struct perf_event *event, int flags)
8446 if (flags & PERF_EF_START)
8447 cpu_clock_event_start(event, flags);
8448 perf_event_update_userpage(event);
8453 static void cpu_clock_event_del(struct perf_event *event, int flags)
8455 cpu_clock_event_stop(event, flags);
8458 static void cpu_clock_event_read(struct perf_event *event)
8460 cpu_clock_event_update(event);
8463 static int cpu_clock_event_init(struct perf_event *event)
8465 if (event->attr.type != PERF_TYPE_SOFTWARE)
8468 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8472 * no branch sampling for software events
8474 if (has_branch_stack(event))
8477 perf_swevent_init_hrtimer(event);
8482 static struct pmu perf_cpu_clock = {
8483 .task_ctx_nr = perf_sw_context,
8485 .capabilities = PERF_PMU_CAP_NO_NMI,
8487 .event_init = cpu_clock_event_init,
8488 .add = cpu_clock_event_add,
8489 .del = cpu_clock_event_del,
8490 .start = cpu_clock_event_start,
8491 .stop = cpu_clock_event_stop,
8492 .read = cpu_clock_event_read,
8496 * Software event: task time clock
8499 static void task_clock_event_update(struct perf_event *event, u64 now)
8504 prev = local64_xchg(&event->hw.prev_count, now);
8506 local64_add(delta, &event->count);
8509 static void task_clock_event_start(struct perf_event *event, int flags)
8511 local64_set(&event->hw.prev_count, event->ctx->time);
8512 perf_swevent_start_hrtimer(event);
8515 static void task_clock_event_stop(struct perf_event *event, int flags)
8517 perf_swevent_cancel_hrtimer(event);
8518 task_clock_event_update(event, event->ctx->time);
8521 static int task_clock_event_add(struct perf_event *event, int flags)
8523 if (flags & PERF_EF_START)
8524 task_clock_event_start(event, flags);
8525 perf_event_update_userpage(event);
8530 static void task_clock_event_del(struct perf_event *event, int flags)
8532 task_clock_event_stop(event, PERF_EF_UPDATE);
8535 static void task_clock_event_read(struct perf_event *event)
8537 u64 now = perf_clock();
8538 u64 delta = now - event->ctx->timestamp;
8539 u64 time = event->ctx->time + delta;
8541 task_clock_event_update(event, time);
8544 static int task_clock_event_init(struct perf_event *event)
8546 if (event->attr.type != PERF_TYPE_SOFTWARE)
8549 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8553 * no branch sampling for software events
8555 if (has_branch_stack(event))
8558 perf_swevent_init_hrtimer(event);
8563 static struct pmu perf_task_clock = {
8564 .task_ctx_nr = perf_sw_context,
8566 .capabilities = PERF_PMU_CAP_NO_NMI,
8568 .event_init = task_clock_event_init,
8569 .add = task_clock_event_add,
8570 .del = task_clock_event_del,
8571 .start = task_clock_event_start,
8572 .stop = task_clock_event_stop,
8573 .read = task_clock_event_read,
8576 static void perf_pmu_nop_void(struct pmu *pmu)
8580 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8584 static int perf_pmu_nop_int(struct pmu *pmu)
8589 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8591 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8593 __this_cpu_write(nop_txn_flags, flags);
8595 if (flags & ~PERF_PMU_TXN_ADD)
8598 perf_pmu_disable(pmu);
8601 static int perf_pmu_commit_txn(struct pmu *pmu)
8603 unsigned int flags = __this_cpu_read(nop_txn_flags);
8605 __this_cpu_write(nop_txn_flags, 0);
8607 if (flags & ~PERF_PMU_TXN_ADD)
8610 perf_pmu_enable(pmu);
8614 static void perf_pmu_cancel_txn(struct pmu *pmu)
8616 unsigned int flags = __this_cpu_read(nop_txn_flags);
8618 __this_cpu_write(nop_txn_flags, 0);
8620 if (flags & ~PERF_PMU_TXN_ADD)
8623 perf_pmu_enable(pmu);
8626 static int perf_event_idx_default(struct perf_event *event)
8632 * Ensures all contexts with the same task_ctx_nr have the same
8633 * pmu_cpu_context too.
8635 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8642 list_for_each_entry(pmu, &pmus, entry) {
8643 if (pmu->task_ctx_nr == ctxn)
8644 return pmu->pmu_cpu_context;
8650 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8654 for_each_possible_cpu(cpu) {
8655 struct perf_cpu_context *cpuctx;
8657 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8659 if (cpuctx->unique_pmu == old_pmu)
8660 cpuctx->unique_pmu = pmu;
8664 static void free_pmu_context(struct pmu *pmu)
8668 mutex_lock(&pmus_lock);
8670 * Like a real lame refcount.
8672 list_for_each_entry(i, &pmus, entry) {
8673 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8674 update_pmu_context(i, pmu);
8679 free_percpu(pmu->pmu_cpu_context);
8681 mutex_unlock(&pmus_lock);
8685 * Let userspace know that this PMU supports address range filtering:
8687 static ssize_t nr_addr_filters_show(struct device *dev,
8688 struct device_attribute *attr,
8691 struct pmu *pmu = dev_get_drvdata(dev);
8693 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8695 DEVICE_ATTR_RO(nr_addr_filters);
8697 static struct idr pmu_idr;
8700 type_show(struct device *dev, struct device_attribute *attr, char *page)
8702 struct pmu *pmu = dev_get_drvdata(dev);
8704 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8706 static DEVICE_ATTR_RO(type);
8709 perf_event_mux_interval_ms_show(struct device *dev,
8710 struct device_attribute *attr,
8713 struct pmu *pmu = dev_get_drvdata(dev);
8715 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8718 static DEFINE_MUTEX(mux_interval_mutex);
8721 perf_event_mux_interval_ms_store(struct device *dev,
8722 struct device_attribute *attr,
8723 const char *buf, size_t count)
8725 struct pmu *pmu = dev_get_drvdata(dev);
8726 int timer, cpu, ret;
8728 ret = kstrtoint(buf, 0, &timer);
8735 /* same value, noting to do */
8736 if (timer == pmu->hrtimer_interval_ms)
8739 mutex_lock(&mux_interval_mutex);
8740 pmu->hrtimer_interval_ms = timer;
8742 /* update all cpuctx for this PMU */
8744 for_each_online_cpu(cpu) {
8745 struct perf_cpu_context *cpuctx;
8746 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8747 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8749 cpu_function_call(cpu,
8750 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8753 mutex_unlock(&mux_interval_mutex);
8757 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8759 static struct attribute *pmu_dev_attrs[] = {
8760 &dev_attr_type.attr,
8761 &dev_attr_perf_event_mux_interval_ms.attr,
8764 ATTRIBUTE_GROUPS(pmu_dev);
8766 static int pmu_bus_running;
8767 static struct bus_type pmu_bus = {
8768 .name = "event_source",
8769 .dev_groups = pmu_dev_groups,
8772 static void pmu_dev_release(struct device *dev)
8777 static int pmu_dev_alloc(struct pmu *pmu)
8781 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8785 pmu->dev->groups = pmu->attr_groups;
8786 device_initialize(pmu->dev);
8787 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8791 dev_set_drvdata(pmu->dev, pmu);
8792 pmu->dev->bus = &pmu_bus;
8793 pmu->dev->release = pmu_dev_release;
8794 ret = device_add(pmu->dev);
8798 /* For PMUs with address filters, throw in an extra attribute: */
8799 if (pmu->nr_addr_filters)
8800 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8809 device_del(pmu->dev);
8812 put_device(pmu->dev);
8816 static struct lock_class_key cpuctx_mutex;
8817 static struct lock_class_key cpuctx_lock;
8819 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8823 mutex_lock(&pmus_lock);
8825 pmu->pmu_disable_count = alloc_percpu(int);
8826 if (!pmu->pmu_disable_count)
8835 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8843 if (pmu_bus_running) {
8844 ret = pmu_dev_alloc(pmu);
8850 if (pmu->task_ctx_nr == perf_hw_context) {
8851 static int hw_context_taken = 0;
8854 * Other than systems with heterogeneous CPUs, it never makes
8855 * sense for two PMUs to share perf_hw_context. PMUs which are
8856 * uncore must use perf_invalid_context.
8858 if (WARN_ON_ONCE(hw_context_taken &&
8859 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8860 pmu->task_ctx_nr = perf_invalid_context;
8862 hw_context_taken = 1;
8865 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8866 if (pmu->pmu_cpu_context)
8867 goto got_cpu_context;
8870 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8871 if (!pmu->pmu_cpu_context)
8874 for_each_possible_cpu(cpu) {
8875 struct perf_cpu_context *cpuctx;
8877 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8878 __perf_event_init_context(&cpuctx->ctx);
8879 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8880 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8881 cpuctx->ctx.pmu = pmu;
8883 __perf_mux_hrtimer_init(cpuctx, cpu);
8885 cpuctx->unique_pmu = pmu;
8889 if (!pmu->start_txn) {
8890 if (pmu->pmu_enable) {
8892 * If we have pmu_enable/pmu_disable calls, install
8893 * transaction stubs that use that to try and batch
8894 * hardware accesses.
8896 pmu->start_txn = perf_pmu_start_txn;
8897 pmu->commit_txn = perf_pmu_commit_txn;
8898 pmu->cancel_txn = perf_pmu_cancel_txn;
8900 pmu->start_txn = perf_pmu_nop_txn;
8901 pmu->commit_txn = perf_pmu_nop_int;
8902 pmu->cancel_txn = perf_pmu_nop_void;
8906 if (!pmu->pmu_enable) {
8907 pmu->pmu_enable = perf_pmu_nop_void;
8908 pmu->pmu_disable = perf_pmu_nop_void;
8911 if (!pmu->event_idx)
8912 pmu->event_idx = perf_event_idx_default;
8914 list_add_rcu(&pmu->entry, &pmus);
8915 atomic_set(&pmu->exclusive_cnt, 0);
8918 mutex_unlock(&pmus_lock);
8923 device_del(pmu->dev);
8924 put_device(pmu->dev);
8927 if (pmu->type >= PERF_TYPE_MAX)
8928 idr_remove(&pmu_idr, pmu->type);
8931 free_percpu(pmu->pmu_disable_count);
8934 EXPORT_SYMBOL_GPL(perf_pmu_register);
8936 void perf_pmu_unregister(struct pmu *pmu)
8940 mutex_lock(&pmus_lock);
8941 remove_device = pmu_bus_running;
8942 list_del_rcu(&pmu->entry);
8943 mutex_unlock(&pmus_lock);
8946 * We dereference the pmu list under both SRCU and regular RCU, so
8947 * synchronize against both of those.
8949 synchronize_srcu(&pmus_srcu);
8952 free_percpu(pmu->pmu_disable_count);
8953 if (pmu->type >= PERF_TYPE_MAX)
8954 idr_remove(&pmu_idr, pmu->type);
8955 if (remove_device) {
8956 if (pmu->nr_addr_filters)
8957 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8958 device_del(pmu->dev);
8959 put_device(pmu->dev);
8961 free_pmu_context(pmu);
8963 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8965 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8967 struct perf_event_context *ctx = NULL;
8970 if (!try_module_get(pmu->module))
8973 if (event->group_leader != event) {
8975 * This ctx->mutex can nest when we're called through
8976 * inheritance. See the perf_event_ctx_lock_nested() comment.
8978 ctx = perf_event_ctx_lock_nested(event->group_leader,
8979 SINGLE_DEPTH_NESTING);
8984 ret = pmu->event_init(event);
8987 perf_event_ctx_unlock(event->group_leader, ctx);
8990 module_put(pmu->module);
8995 static struct pmu *perf_init_event(struct perf_event *event)
8997 struct pmu *pmu = NULL;
9001 idx = srcu_read_lock(&pmus_srcu);
9004 pmu = idr_find(&pmu_idr, event->attr.type);
9007 ret = perf_try_init_event(pmu, event);
9013 list_for_each_entry_rcu(pmu, &pmus, entry) {
9014 ret = perf_try_init_event(pmu, event);
9018 if (ret != -ENOENT) {
9023 pmu = ERR_PTR(-ENOENT);
9025 srcu_read_unlock(&pmus_srcu, idx);
9030 static void attach_sb_event(struct perf_event *event)
9032 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9034 raw_spin_lock(&pel->lock);
9035 list_add_rcu(&event->sb_list, &pel->list);
9036 raw_spin_unlock(&pel->lock);
9040 * We keep a list of all !task (and therefore per-cpu) events
9041 * that need to receive side-band records.
9043 * This avoids having to scan all the various PMU per-cpu contexts
9046 static void account_pmu_sb_event(struct perf_event *event)
9048 if (is_sb_event(event))
9049 attach_sb_event(event);
9052 static void account_event_cpu(struct perf_event *event, int cpu)
9057 if (is_cgroup_event(event))
9058 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9061 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9062 static void account_freq_event_nohz(void)
9064 #ifdef CONFIG_NO_HZ_FULL
9065 /* Lock so we don't race with concurrent unaccount */
9066 spin_lock(&nr_freq_lock);
9067 if (atomic_inc_return(&nr_freq_events) == 1)
9068 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9069 spin_unlock(&nr_freq_lock);
9073 static void account_freq_event(void)
9075 if (tick_nohz_full_enabled())
9076 account_freq_event_nohz();
9078 atomic_inc(&nr_freq_events);
9082 static void account_event(struct perf_event *event)
9089 if (event->attach_state & PERF_ATTACH_TASK)
9091 if (event->attr.mmap || event->attr.mmap_data)
9092 atomic_inc(&nr_mmap_events);
9093 if (event->attr.comm)
9094 atomic_inc(&nr_comm_events);
9095 if (event->attr.task)
9096 atomic_inc(&nr_task_events);
9097 if (event->attr.freq)
9098 account_freq_event();
9099 if (event->attr.context_switch) {
9100 atomic_inc(&nr_switch_events);
9103 if (has_branch_stack(event))
9105 if (is_cgroup_event(event))
9109 if (atomic_inc_not_zero(&perf_sched_count))
9112 mutex_lock(&perf_sched_mutex);
9113 if (!atomic_read(&perf_sched_count)) {
9114 static_branch_enable(&perf_sched_events);
9116 * Guarantee that all CPUs observe they key change and
9117 * call the perf scheduling hooks before proceeding to
9118 * install events that need them.
9120 synchronize_sched();
9123 * Now that we have waited for the sync_sched(), allow further
9124 * increments to by-pass the mutex.
9126 atomic_inc(&perf_sched_count);
9127 mutex_unlock(&perf_sched_mutex);
9131 account_event_cpu(event, event->cpu);
9133 account_pmu_sb_event(event);
9137 * Allocate and initialize a event structure
9139 static struct perf_event *
9140 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9141 struct task_struct *task,
9142 struct perf_event *group_leader,
9143 struct perf_event *parent_event,
9144 perf_overflow_handler_t overflow_handler,
9145 void *context, int cgroup_fd)
9148 struct perf_event *event;
9149 struct hw_perf_event *hwc;
9152 if ((unsigned)cpu >= nr_cpu_ids) {
9153 if (!task || cpu != -1)
9154 return ERR_PTR(-EINVAL);
9157 event = kzalloc(sizeof(*event), GFP_KERNEL);
9159 return ERR_PTR(-ENOMEM);
9162 * Single events are their own group leaders, with an
9163 * empty sibling list:
9166 group_leader = event;
9168 mutex_init(&event->child_mutex);
9169 INIT_LIST_HEAD(&event->child_list);
9171 INIT_LIST_HEAD(&event->group_entry);
9172 INIT_LIST_HEAD(&event->event_entry);
9173 INIT_LIST_HEAD(&event->sibling_list);
9174 INIT_LIST_HEAD(&event->rb_entry);
9175 INIT_LIST_HEAD(&event->active_entry);
9176 INIT_LIST_HEAD(&event->addr_filters.list);
9177 INIT_HLIST_NODE(&event->hlist_entry);
9180 init_waitqueue_head(&event->waitq);
9181 init_irq_work(&event->pending, perf_pending_event);
9183 mutex_init(&event->mmap_mutex);
9184 raw_spin_lock_init(&event->addr_filters.lock);
9186 atomic_long_set(&event->refcount, 1);
9188 event->attr = *attr;
9189 event->group_leader = group_leader;
9193 event->parent = parent_event;
9195 event->ns = get_pid_ns(task_active_pid_ns(current));
9196 event->id = atomic64_inc_return(&perf_event_id);
9198 event->state = PERF_EVENT_STATE_INACTIVE;
9201 event->attach_state = PERF_ATTACH_TASK;
9203 * XXX pmu::event_init needs to know what task to account to
9204 * and we cannot use the ctx information because we need the
9205 * pmu before we get a ctx.
9207 event->hw.target = task;
9210 event->clock = &local_clock;
9212 event->clock = parent_event->clock;
9214 if (!overflow_handler && parent_event) {
9215 overflow_handler = parent_event->overflow_handler;
9216 context = parent_event->overflow_handler_context;
9217 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9218 if (overflow_handler == bpf_overflow_handler) {
9219 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9222 err = PTR_ERR(prog);
9226 event->orig_overflow_handler =
9227 parent_event->orig_overflow_handler;
9232 if (overflow_handler) {
9233 event->overflow_handler = overflow_handler;
9234 event->overflow_handler_context = context;
9235 } else if (is_write_backward(event)){
9236 event->overflow_handler = perf_event_output_backward;
9237 event->overflow_handler_context = NULL;
9239 event->overflow_handler = perf_event_output_forward;
9240 event->overflow_handler_context = NULL;
9243 perf_event__state_init(event);
9248 hwc->sample_period = attr->sample_period;
9249 if (attr->freq && attr->sample_freq)
9250 hwc->sample_period = 1;
9251 hwc->last_period = hwc->sample_period;
9253 local64_set(&hwc->period_left, hwc->sample_period);
9256 * we currently do not support PERF_FORMAT_GROUP on inherited events
9258 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9261 if (!has_branch_stack(event))
9262 event->attr.branch_sample_type = 0;
9264 if (cgroup_fd != -1) {
9265 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9270 pmu = perf_init_event(event);
9273 else if (IS_ERR(pmu)) {
9278 err = exclusive_event_init(event);
9282 if (has_addr_filter(event)) {
9283 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9284 sizeof(unsigned long),
9286 if (!event->addr_filters_offs)
9289 /* force hw sync on the address filters */
9290 event->addr_filters_gen = 1;
9293 if (!event->parent) {
9294 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9295 err = get_callchain_buffers(attr->sample_max_stack);
9297 goto err_addr_filters;
9301 /* symmetric to unaccount_event() in _free_event() */
9302 account_event(event);
9307 kfree(event->addr_filters_offs);
9310 exclusive_event_destroy(event);
9314 event->destroy(event);
9315 module_put(pmu->module);
9317 if (is_cgroup_event(event))
9318 perf_detach_cgroup(event);
9320 put_pid_ns(event->ns);
9323 return ERR_PTR(err);
9326 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9327 struct perf_event_attr *attr)
9332 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9336 * zero the full structure, so that a short copy will be nice.
9338 memset(attr, 0, sizeof(*attr));
9340 ret = get_user(size, &uattr->size);
9344 if (size > PAGE_SIZE) /* silly large */
9347 if (!size) /* abi compat */
9348 size = PERF_ATTR_SIZE_VER0;
9350 if (size < PERF_ATTR_SIZE_VER0)
9354 * If we're handed a bigger struct than we know of,
9355 * ensure all the unknown bits are 0 - i.e. new
9356 * user-space does not rely on any kernel feature
9357 * extensions we dont know about yet.
9359 if (size > sizeof(*attr)) {
9360 unsigned char __user *addr;
9361 unsigned char __user *end;
9364 addr = (void __user *)uattr + sizeof(*attr);
9365 end = (void __user *)uattr + size;
9367 for (; addr < end; addr++) {
9368 ret = get_user(val, addr);
9374 size = sizeof(*attr);
9377 ret = copy_from_user(attr, uattr, size);
9381 if (attr->__reserved_1)
9384 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9387 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9390 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9391 u64 mask = attr->branch_sample_type;
9393 /* only using defined bits */
9394 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9397 /* at least one branch bit must be set */
9398 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9401 /* propagate priv level, when not set for branch */
9402 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9404 /* exclude_kernel checked on syscall entry */
9405 if (!attr->exclude_kernel)
9406 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9408 if (!attr->exclude_user)
9409 mask |= PERF_SAMPLE_BRANCH_USER;
9411 if (!attr->exclude_hv)
9412 mask |= PERF_SAMPLE_BRANCH_HV;
9414 * adjust user setting (for HW filter setup)
9416 attr->branch_sample_type = mask;
9418 /* privileged levels capture (kernel, hv): check permissions */
9419 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9420 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9424 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9425 ret = perf_reg_validate(attr->sample_regs_user);
9430 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9431 if (!arch_perf_have_user_stack_dump())
9435 * We have __u32 type for the size, but so far
9436 * we can only use __u16 as maximum due to the
9437 * __u16 sample size limit.
9439 if (attr->sample_stack_user >= USHRT_MAX)
9441 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9445 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9446 ret = perf_reg_validate(attr->sample_regs_intr);
9451 put_user(sizeof(*attr), &uattr->size);
9457 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9459 struct ring_buffer *rb = NULL;
9465 /* don't allow circular references */
9466 if (event == output_event)
9470 * Don't allow cross-cpu buffers
9472 if (output_event->cpu != event->cpu)
9476 * If its not a per-cpu rb, it must be the same task.
9478 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9482 * Mixing clocks in the same buffer is trouble you don't need.
9484 if (output_event->clock != event->clock)
9488 * Either writing ring buffer from beginning or from end.
9489 * Mixing is not allowed.
9491 if (is_write_backward(output_event) != is_write_backward(event))
9495 * If both events generate aux data, they must be on the same PMU
9497 if (has_aux(event) && has_aux(output_event) &&
9498 event->pmu != output_event->pmu)
9502 mutex_lock(&event->mmap_mutex);
9503 /* Can't redirect output if we've got an active mmap() */
9504 if (atomic_read(&event->mmap_count))
9508 /* get the rb we want to redirect to */
9509 rb = ring_buffer_get(output_event);
9514 ring_buffer_attach(event, rb);
9518 mutex_unlock(&event->mmap_mutex);
9524 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9530 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9533 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9535 bool nmi_safe = false;
9538 case CLOCK_MONOTONIC:
9539 event->clock = &ktime_get_mono_fast_ns;
9543 case CLOCK_MONOTONIC_RAW:
9544 event->clock = &ktime_get_raw_fast_ns;
9548 case CLOCK_REALTIME:
9549 event->clock = &ktime_get_real_ns;
9552 case CLOCK_BOOTTIME:
9553 event->clock = &ktime_get_boot_ns;
9557 event->clock = &ktime_get_tai_ns;
9564 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9571 * Variation on perf_event_ctx_lock_nested(), except we take two context
9574 static struct perf_event_context *
9575 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9576 struct perf_event_context *ctx)
9578 struct perf_event_context *gctx;
9582 gctx = READ_ONCE(group_leader->ctx);
9583 if (!atomic_inc_not_zero(&gctx->refcount)) {
9589 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9591 if (group_leader->ctx != gctx) {
9592 mutex_unlock(&ctx->mutex);
9593 mutex_unlock(&gctx->mutex);
9602 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9604 * @attr_uptr: event_id type attributes for monitoring/sampling
9607 * @group_fd: group leader event fd
9609 SYSCALL_DEFINE5(perf_event_open,
9610 struct perf_event_attr __user *, attr_uptr,
9611 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9613 struct perf_event *group_leader = NULL, *output_event = NULL;
9614 struct perf_event *event, *sibling;
9615 struct perf_event_attr attr;
9616 struct perf_event_context *ctx, *uninitialized_var(gctx);
9617 struct file *event_file = NULL;
9618 struct fd group = {NULL, 0};
9619 struct task_struct *task = NULL;
9624 int f_flags = O_RDWR;
9627 /* for future expandability... */
9628 if (flags & ~PERF_FLAG_ALL)
9631 err = perf_copy_attr(attr_uptr, &attr);
9635 if (!attr.exclude_kernel) {
9636 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9641 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9644 if (attr.sample_period & (1ULL << 63))
9648 if (!attr.sample_max_stack)
9649 attr.sample_max_stack = sysctl_perf_event_max_stack;
9652 * In cgroup mode, the pid argument is used to pass the fd
9653 * opened to the cgroup directory in cgroupfs. The cpu argument
9654 * designates the cpu on which to monitor threads from that
9657 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9660 if (flags & PERF_FLAG_FD_CLOEXEC)
9661 f_flags |= O_CLOEXEC;
9663 event_fd = get_unused_fd_flags(f_flags);
9667 if (group_fd != -1) {
9668 err = perf_fget_light(group_fd, &group);
9671 group_leader = group.file->private_data;
9672 if (flags & PERF_FLAG_FD_OUTPUT)
9673 output_event = group_leader;
9674 if (flags & PERF_FLAG_FD_NO_GROUP)
9675 group_leader = NULL;
9678 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9679 task = find_lively_task_by_vpid(pid);
9681 err = PTR_ERR(task);
9686 if (task && group_leader &&
9687 group_leader->attr.inherit != attr.inherit) {
9695 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9700 * Reuse ptrace permission checks for now.
9702 * We must hold cred_guard_mutex across this and any potential
9703 * perf_install_in_context() call for this new event to
9704 * serialize against exec() altering our credentials (and the
9705 * perf_event_exit_task() that could imply).
9708 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9712 if (flags & PERF_FLAG_PID_CGROUP)
9715 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9716 NULL, NULL, cgroup_fd);
9717 if (IS_ERR(event)) {
9718 err = PTR_ERR(event);
9722 if (is_sampling_event(event)) {
9723 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9730 * Special case software events and allow them to be part of
9731 * any hardware group.
9735 if (attr.use_clockid) {
9736 err = perf_event_set_clock(event, attr.clockid);
9741 if (pmu->task_ctx_nr == perf_sw_context)
9742 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9745 (is_software_event(event) != is_software_event(group_leader))) {
9746 if (is_software_event(event)) {
9748 * If event and group_leader are not both a software
9749 * event, and event is, then group leader is not.
9751 * Allow the addition of software events to !software
9752 * groups, this is safe because software events never
9755 pmu = group_leader->pmu;
9756 } else if (is_software_event(group_leader) &&
9757 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9759 * In case the group is a pure software group, and we
9760 * try to add a hardware event, move the whole group to
9761 * the hardware context.
9768 * Get the target context (task or percpu):
9770 ctx = find_get_context(pmu, task, event);
9776 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9782 * Look up the group leader (we will attach this event to it):
9788 * Do not allow a recursive hierarchy (this new sibling
9789 * becoming part of another group-sibling):
9791 if (group_leader->group_leader != group_leader)
9794 /* All events in a group should have the same clock */
9795 if (group_leader->clock != event->clock)
9799 * Do not allow to attach to a group in a different
9800 * task or CPU context:
9804 * Make sure we're both on the same task, or both
9807 if (group_leader->ctx->task != ctx->task)
9811 * Make sure we're both events for the same CPU;
9812 * grouping events for different CPUs is broken; since
9813 * you can never concurrently schedule them anyhow.
9815 if (group_leader->cpu != event->cpu)
9818 if (group_leader->ctx != ctx)
9823 * Only a group leader can be exclusive or pinned
9825 if (attr.exclusive || attr.pinned)
9830 err = perf_event_set_output(event, output_event);
9835 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9837 if (IS_ERR(event_file)) {
9838 err = PTR_ERR(event_file);
9844 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
9846 if (gctx->task == TASK_TOMBSTONE) {
9852 * Check if we raced against another sys_perf_event_open() call
9853 * moving the software group underneath us.
9855 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9857 * If someone moved the group out from under us, check
9858 * if this new event wound up on the same ctx, if so
9859 * its the regular !move_group case, otherwise fail.
9865 perf_event_ctx_unlock(group_leader, gctx);
9870 mutex_lock(&ctx->mutex);
9873 if (ctx->task == TASK_TOMBSTONE) {
9878 if (!perf_event_validate_size(event)) {
9884 * Must be under the same ctx::mutex as perf_install_in_context(),
9885 * because we need to serialize with concurrent event creation.
9887 if (!exclusive_event_installable(event, ctx)) {
9888 /* exclusive and group stuff are assumed mutually exclusive */
9889 WARN_ON_ONCE(move_group);
9895 WARN_ON_ONCE(ctx->parent_ctx);
9898 * This is the point on no return; we cannot fail hereafter. This is
9899 * where we start modifying current state.
9904 * See perf_event_ctx_lock() for comments on the details
9905 * of swizzling perf_event::ctx.
9907 perf_remove_from_context(group_leader, 0);
9909 list_for_each_entry(sibling, &group_leader->sibling_list,
9911 perf_remove_from_context(sibling, 0);
9916 * Wait for everybody to stop referencing the events through
9917 * the old lists, before installing it on new lists.
9922 * Install the group siblings before the group leader.
9924 * Because a group leader will try and install the entire group
9925 * (through the sibling list, which is still in-tact), we can
9926 * end up with siblings installed in the wrong context.
9928 * By installing siblings first we NO-OP because they're not
9929 * reachable through the group lists.
9931 list_for_each_entry(sibling, &group_leader->sibling_list,
9933 perf_event__state_init(sibling);
9934 perf_install_in_context(ctx, sibling, sibling->cpu);
9939 * Removing from the context ends up with disabled
9940 * event. What we want here is event in the initial
9941 * startup state, ready to be add into new context.
9943 perf_event__state_init(group_leader);
9944 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9948 * Now that all events are installed in @ctx, nothing
9949 * references @gctx anymore, so drop the last reference we have
9956 * Precalculate sample_data sizes; do while holding ctx::mutex such
9957 * that we're serialized against further additions and before
9958 * perf_install_in_context() which is the point the event is active and
9959 * can use these values.
9961 perf_event__header_size(event);
9962 perf_event__id_header_size(event);
9964 event->owner = current;
9966 perf_install_in_context(ctx, event, event->cpu);
9967 perf_unpin_context(ctx);
9970 perf_event_ctx_unlock(group_leader, gctx);
9971 mutex_unlock(&ctx->mutex);
9974 mutex_unlock(&task->signal->cred_guard_mutex);
9975 put_task_struct(task);
9980 mutex_lock(¤t->perf_event_mutex);
9981 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9982 mutex_unlock(¤t->perf_event_mutex);
9985 * Drop the reference on the group_event after placing the
9986 * new event on the sibling_list. This ensures destruction
9987 * of the group leader will find the pointer to itself in
9988 * perf_group_detach().
9991 fd_install(event_fd, event_file);
9996 perf_event_ctx_unlock(group_leader, gctx);
9997 mutex_unlock(&ctx->mutex);
10001 perf_unpin_context(ctx);
10005 * If event_file is set, the fput() above will have called ->release()
10006 * and that will take care of freeing the event.
10012 mutex_unlock(&task->signal->cred_guard_mutex);
10017 put_task_struct(task);
10021 put_unused_fd(event_fd);
10026 * perf_event_create_kernel_counter
10028 * @attr: attributes of the counter to create
10029 * @cpu: cpu in which the counter is bound
10030 * @task: task to profile (NULL for percpu)
10032 struct perf_event *
10033 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10034 struct task_struct *task,
10035 perf_overflow_handler_t overflow_handler,
10038 struct perf_event_context *ctx;
10039 struct perf_event *event;
10043 * Get the target context (task or percpu):
10046 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10047 overflow_handler, context, -1);
10048 if (IS_ERR(event)) {
10049 err = PTR_ERR(event);
10053 /* Mark owner so we could distinguish it from user events. */
10054 event->owner = TASK_TOMBSTONE;
10056 ctx = find_get_context(event->pmu, task, event);
10058 err = PTR_ERR(ctx);
10062 WARN_ON_ONCE(ctx->parent_ctx);
10063 mutex_lock(&ctx->mutex);
10064 if (ctx->task == TASK_TOMBSTONE) {
10069 if (!exclusive_event_installable(event, ctx)) {
10074 perf_install_in_context(ctx, event, cpu);
10075 perf_unpin_context(ctx);
10076 mutex_unlock(&ctx->mutex);
10081 mutex_unlock(&ctx->mutex);
10082 perf_unpin_context(ctx);
10087 return ERR_PTR(err);
10089 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10091 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10093 struct perf_event_context *src_ctx;
10094 struct perf_event_context *dst_ctx;
10095 struct perf_event *event, *tmp;
10098 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10099 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10102 * See perf_event_ctx_lock() for comments on the details
10103 * of swizzling perf_event::ctx.
10105 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10106 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10108 perf_remove_from_context(event, 0);
10109 unaccount_event_cpu(event, src_cpu);
10111 list_add(&event->migrate_entry, &events);
10115 * Wait for the events to quiesce before re-instating them.
10120 * Re-instate events in 2 passes.
10122 * Skip over group leaders and only install siblings on this first
10123 * pass, siblings will not get enabled without a leader, however a
10124 * leader will enable its siblings, even if those are still on the old
10127 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10128 if (event->group_leader == event)
10131 list_del(&event->migrate_entry);
10132 if (event->state >= PERF_EVENT_STATE_OFF)
10133 event->state = PERF_EVENT_STATE_INACTIVE;
10134 account_event_cpu(event, dst_cpu);
10135 perf_install_in_context(dst_ctx, event, dst_cpu);
10140 * Once all the siblings are setup properly, install the group leaders
10143 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10144 list_del(&event->migrate_entry);
10145 if (event->state >= PERF_EVENT_STATE_OFF)
10146 event->state = PERF_EVENT_STATE_INACTIVE;
10147 account_event_cpu(event, dst_cpu);
10148 perf_install_in_context(dst_ctx, event, dst_cpu);
10151 mutex_unlock(&dst_ctx->mutex);
10152 mutex_unlock(&src_ctx->mutex);
10154 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10156 static void sync_child_event(struct perf_event *child_event,
10157 struct task_struct *child)
10159 struct perf_event *parent_event = child_event->parent;
10162 if (child_event->attr.inherit_stat)
10163 perf_event_read_event(child_event, child);
10165 child_val = perf_event_count(child_event);
10168 * Add back the child's count to the parent's count:
10170 atomic64_add(child_val, &parent_event->child_count);
10171 atomic64_add(child_event->total_time_enabled,
10172 &parent_event->child_total_time_enabled);
10173 atomic64_add(child_event->total_time_running,
10174 &parent_event->child_total_time_running);
10178 perf_event_exit_event(struct perf_event *child_event,
10179 struct perf_event_context *child_ctx,
10180 struct task_struct *child)
10182 struct perf_event *parent_event = child_event->parent;
10185 * Do not destroy the 'original' grouping; because of the context
10186 * switch optimization the original events could've ended up in a
10187 * random child task.
10189 * If we were to destroy the original group, all group related
10190 * operations would cease to function properly after this random
10193 * Do destroy all inherited groups, we don't care about those
10194 * and being thorough is better.
10196 raw_spin_lock_irq(&child_ctx->lock);
10197 WARN_ON_ONCE(child_ctx->is_active);
10200 perf_group_detach(child_event);
10201 list_del_event(child_event, child_ctx);
10202 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10203 raw_spin_unlock_irq(&child_ctx->lock);
10206 * Parent events are governed by their filedesc, retain them.
10208 if (!parent_event) {
10209 perf_event_wakeup(child_event);
10213 * Child events can be cleaned up.
10216 sync_child_event(child_event, child);
10219 * Remove this event from the parent's list
10221 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10222 mutex_lock(&parent_event->child_mutex);
10223 list_del_init(&child_event->child_list);
10224 mutex_unlock(&parent_event->child_mutex);
10227 * Kick perf_poll() for is_event_hup().
10229 perf_event_wakeup(parent_event);
10230 free_event(child_event);
10231 put_event(parent_event);
10234 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10236 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10237 struct perf_event *child_event, *next;
10239 WARN_ON_ONCE(child != current);
10241 child_ctx = perf_pin_task_context(child, ctxn);
10246 * In order to reduce the amount of tricky in ctx tear-down, we hold
10247 * ctx::mutex over the entire thing. This serializes against almost
10248 * everything that wants to access the ctx.
10250 * The exception is sys_perf_event_open() /
10251 * perf_event_create_kernel_count() which does find_get_context()
10252 * without ctx::mutex (it cannot because of the move_group double mutex
10253 * lock thing). See the comments in perf_install_in_context().
10255 mutex_lock(&child_ctx->mutex);
10258 * In a single ctx::lock section, de-schedule the events and detach the
10259 * context from the task such that we cannot ever get it scheduled back
10262 raw_spin_lock_irq(&child_ctx->lock);
10263 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
10266 * Now that the context is inactive, destroy the task <-> ctx relation
10267 * and mark the context dead.
10269 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10270 put_ctx(child_ctx); /* cannot be last */
10271 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10272 put_task_struct(current); /* cannot be last */
10274 clone_ctx = unclone_ctx(child_ctx);
10275 raw_spin_unlock_irq(&child_ctx->lock);
10278 put_ctx(clone_ctx);
10281 * Report the task dead after unscheduling the events so that we
10282 * won't get any samples after PERF_RECORD_EXIT. We can however still
10283 * get a few PERF_RECORD_READ events.
10285 perf_event_task(child, child_ctx, 0);
10287 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10288 perf_event_exit_event(child_event, child_ctx, child);
10290 mutex_unlock(&child_ctx->mutex);
10292 put_ctx(child_ctx);
10296 * When a child task exits, feed back event values to parent events.
10298 * Can be called with cred_guard_mutex held when called from
10299 * install_exec_creds().
10301 void perf_event_exit_task(struct task_struct *child)
10303 struct perf_event *event, *tmp;
10306 mutex_lock(&child->perf_event_mutex);
10307 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10309 list_del_init(&event->owner_entry);
10312 * Ensure the list deletion is visible before we clear
10313 * the owner, closes a race against perf_release() where
10314 * we need to serialize on the owner->perf_event_mutex.
10316 smp_store_release(&event->owner, NULL);
10318 mutex_unlock(&child->perf_event_mutex);
10320 for_each_task_context_nr(ctxn)
10321 perf_event_exit_task_context(child, ctxn);
10324 * The perf_event_exit_task_context calls perf_event_task
10325 * with child's task_ctx, which generates EXIT events for
10326 * child contexts and sets child->perf_event_ctxp[] to NULL.
10327 * At this point we need to send EXIT events to cpu contexts.
10329 perf_event_task(child, NULL, 0);
10332 static void perf_free_event(struct perf_event *event,
10333 struct perf_event_context *ctx)
10335 struct perf_event *parent = event->parent;
10337 if (WARN_ON_ONCE(!parent))
10340 mutex_lock(&parent->child_mutex);
10341 list_del_init(&event->child_list);
10342 mutex_unlock(&parent->child_mutex);
10346 raw_spin_lock_irq(&ctx->lock);
10347 perf_group_detach(event);
10348 list_del_event(event, ctx);
10349 raw_spin_unlock_irq(&ctx->lock);
10354 * Free an unexposed, unused context as created by inheritance by
10355 * perf_event_init_task below, used by fork() in case of fail.
10357 * Not all locks are strictly required, but take them anyway to be nice and
10358 * help out with the lockdep assertions.
10360 void perf_event_free_task(struct task_struct *task)
10362 struct perf_event_context *ctx;
10363 struct perf_event *event, *tmp;
10366 for_each_task_context_nr(ctxn) {
10367 ctx = task->perf_event_ctxp[ctxn];
10371 mutex_lock(&ctx->mutex);
10373 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10375 perf_free_event(event, ctx);
10377 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10379 perf_free_event(event, ctx);
10381 if (!list_empty(&ctx->pinned_groups) ||
10382 !list_empty(&ctx->flexible_groups))
10385 mutex_unlock(&ctx->mutex);
10391 void perf_event_delayed_put(struct task_struct *task)
10395 for_each_task_context_nr(ctxn)
10396 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10399 struct file *perf_event_get(unsigned int fd)
10403 file = fget_raw(fd);
10405 return ERR_PTR(-EBADF);
10407 if (file->f_op != &perf_fops) {
10409 return ERR_PTR(-EBADF);
10415 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10418 return ERR_PTR(-EINVAL);
10420 return &event->attr;
10424 * inherit a event from parent task to child task:
10426 static struct perf_event *
10427 inherit_event(struct perf_event *parent_event,
10428 struct task_struct *parent,
10429 struct perf_event_context *parent_ctx,
10430 struct task_struct *child,
10431 struct perf_event *group_leader,
10432 struct perf_event_context *child_ctx)
10434 enum perf_event_active_state parent_state = parent_event->state;
10435 struct perf_event *child_event;
10436 unsigned long flags;
10439 * Instead of creating recursive hierarchies of events,
10440 * we link inherited events back to the original parent,
10441 * which has a filp for sure, which we use as the reference
10444 if (parent_event->parent)
10445 parent_event = parent_event->parent;
10447 child_event = perf_event_alloc(&parent_event->attr,
10450 group_leader, parent_event,
10452 if (IS_ERR(child_event))
10453 return child_event;
10456 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10457 * must be under the same lock in order to serialize against
10458 * perf_event_release_kernel(), such that either we must observe
10459 * is_orphaned_event() or they will observe us on the child_list.
10461 mutex_lock(&parent_event->child_mutex);
10462 if (is_orphaned_event(parent_event) ||
10463 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10464 mutex_unlock(&parent_event->child_mutex);
10465 free_event(child_event);
10469 get_ctx(child_ctx);
10472 * Make the child state follow the state of the parent event,
10473 * not its attr.disabled bit. We hold the parent's mutex,
10474 * so we won't race with perf_event_{en, dis}able_family.
10476 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10477 child_event->state = PERF_EVENT_STATE_INACTIVE;
10479 child_event->state = PERF_EVENT_STATE_OFF;
10481 if (parent_event->attr.freq) {
10482 u64 sample_period = parent_event->hw.sample_period;
10483 struct hw_perf_event *hwc = &child_event->hw;
10485 hwc->sample_period = sample_period;
10486 hwc->last_period = sample_period;
10488 local64_set(&hwc->period_left, sample_period);
10491 child_event->ctx = child_ctx;
10492 child_event->overflow_handler = parent_event->overflow_handler;
10493 child_event->overflow_handler_context
10494 = parent_event->overflow_handler_context;
10497 * Precalculate sample_data sizes
10499 perf_event__header_size(child_event);
10500 perf_event__id_header_size(child_event);
10503 * Link it up in the child's context:
10505 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10506 add_event_to_ctx(child_event, child_ctx);
10507 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10510 * Link this into the parent event's child list
10512 list_add_tail(&child_event->child_list, &parent_event->child_list);
10513 mutex_unlock(&parent_event->child_mutex);
10515 return child_event;
10518 static int inherit_group(struct perf_event *parent_event,
10519 struct task_struct *parent,
10520 struct perf_event_context *parent_ctx,
10521 struct task_struct *child,
10522 struct perf_event_context *child_ctx)
10524 struct perf_event *leader;
10525 struct perf_event *sub;
10526 struct perf_event *child_ctr;
10528 leader = inherit_event(parent_event, parent, parent_ctx,
10529 child, NULL, child_ctx);
10530 if (IS_ERR(leader))
10531 return PTR_ERR(leader);
10532 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10533 child_ctr = inherit_event(sub, parent, parent_ctx,
10534 child, leader, child_ctx);
10535 if (IS_ERR(child_ctr))
10536 return PTR_ERR(child_ctr);
10542 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10543 struct perf_event_context *parent_ctx,
10544 struct task_struct *child, int ctxn,
10545 int *inherited_all)
10548 struct perf_event_context *child_ctx;
10550 if (!event->attr.inherit) {
10551 *inherited_all = 0;
10555 child_ctx = child->perf_event_ctxp[ctxn];
10558 * This is executed from the parent task context, so
10559 * inherit events that have been marked for cloning.
10560 * First allocate and initialize a context for the
10564 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10568 child->perf_event_ctxp[ctxn] = child_ctx;
10571 ret = inherit_group(event, parent, parent_ctx,
10575 *inherited_all = 0;
10581 * Initialize the perf_event context in task_struct
10583 static int perf_event_init_context(struct task_struct *child, int ctxn)
10585 struct perf_event_context *child_ctx, *parent_ctx;
10586 struct perf_event_context *cloned_ctx;
10587 struct perf_event *event;
10588 struct task_struct *parent = current;
10589 int inherited_all = 1;
10590 unsigned long flags;
10593 if (likely(!parent->perf_event_ctxp[ctxn]))
10597 * If the parent's context is a clone, pin it so it won't get
10598 * swapped under us.
10600 parent_ctx = perf_pin_task_context(parent, ctxn);
10605 * No need to check if parent_ctx != NULL here; since we saw
10606 * it non-NULL earlier, the only reason for it to become NULL
10607 * is if we exit, and since we're currently in the middle of
10608 * a fork we can't be exiting at the same time.
10612 * Lock the parent list. No need to lock the child - not PID
10613 * hashed yet and not running, so nobody can access it.
10615 mutex_lock(&parent_ctx->mutex);
10618 * We dont have to disable NMIs - we are only looking at
10619 * the list, not manipulating it:
10621 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10622 ret = inherit_task_group(event, parent, parent_ctx,
10623 child, ctxn, &inherited_all);
10629 * We can't hold ctx->lock when iterating the ->flexible_group list due
10630 * to allocations, but we need to prevent rotation because
10631 * rotate_ctx() will change the list from interrupt context.
10633 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10634 parent_ctx->rotate_disable = 1;
10635 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10637 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10638 ret = inherit_task_group(event, parent, parent_ctx,
10639 child, ctxn, &inherited_all);
10644 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10645 parent_ctx->rotate_disable = 0;
10647 child_ctx = child->perf_event_ctxp[ctxn];
10649 if (child_ctx && inherited_all) {
10651 * Mark the child context as a clone of the parent
10652 * context, or of whatever the parent is a clone of.
10654 * Note that if the parent is a clone, the holding of
10655 * parent_ctx->lock avoids it from being uncloned.
10657 cloned_ctx = parent_ctx->parent_ctx;
10659 child_ctx->parent_ctx = cloned_ctx;
10660 child_ctx->parent_gen = parent_ctx->parent_gen;
10662 child_ctx->parent_ctx = parent_ctx;
10663 child_ctx->parent_gen = parent_ctx->generation;
10665 get_ctx(child_ctx->parent_ctx);
10668 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10669 mutex_unlock(&parent_ctx->mutex);
10671 perf_unpin_context(parent_ctx);
10672 put_ctx(parent_ctx);
10678 * Initialize the perf_event context in task_struct
10680 int perf_event_init_task(struct task_struct *child)
10684 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10685 mutex_init(&child->perf_event_mutex);
10686 INIT_LIST_HEAD(&child->perf_event_list);
10688 for_each_task_context_nr(ctxn) {
10689 ret = perf_event_init_context(child, ctxn);
10691 perf_event_free_task(child);
10699 static void __init perf_event_init_all_cpus(void)
10701 struct swevent_htable *swhash;
10704 for_each_possible_cpu(cpu) {
10705 swhash = &per_cpu(swevent_htable, cpu);
10706 mutex_init(&swhash->hlist_mutex);
10707 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10709 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10710 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10712 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10716 int perf_event_init_cpu(unsigned int cpu)
10718 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10720 mutex_lock(&swhash->hlist_mutex);
10721 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10722 struct swevent_hlist *hlist;
10724 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10726 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10728 mutex_unlock(&swhash->hlist_mutex);
10732 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10733 static void __perf_event_exit_context(void *__info)
10735 struct perf_event_context *ctx = __info;
10736 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10737 struct perf_event *event;
10739 raw_spin_lock(&ctx->lock);
10740 list_for_each_entry(event, &ctx->event_list, event_entry)
10741 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10742 raw_spin_unlock(&ctx->lock);
10745 static void perf_event_exit_cpu_context(int cpu)
10747 struct perf_event_context *ctx;
10751 idx = srcu_read_lock(&pmus_srcu);
10752 list_for_each_entry_rcu(pmu, &pmus, entry) {
10753 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10755 mutex_lock(&ctx->mutex);
10756 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10757 mutex_unlock(&ctx->mutex);
10759 srcu_read_unlock(&pmus_srcu, idx);
10763 static void perf_event_exit_cpu_context(int cpu) { }
10767 int perf_event_exit_cpu(unsigned int cpu)
10769 perf_event_exit_cpu_context(cpu);
10774 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10778 for_each_online_cpu(cpu)
10779 perf_event_exit_cpu(cpu);
10785 * Run the perf reboot notifier at the very last possible moment so that
10786 * the generic watchdog code runs as long as possible.
10788 static struct notifier_block perf_reboot_notifier = {
10789 .notifier_call = perf_reboot,
10790 .priority = INT_MIN,
10793 void __init perf_event_init(void)
10797 idr_init(&pmu_idr);
10799 perf_event_init_all_cpus();
10800 init_srcu_struct(&pmus_srcu);
10801 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10802 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10803 perf_pmu_register(&perf_task_clock, NULL, -1);
10804 perf_tp_register();
10805 perf_event_init_cpu(smp_processor_id());
10806 register_reboot_notifier(&perf_reboot_notifier);
10808 ret = init_hw_breakpoint();
10809 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10812 * Build time assertion that we keep the data_head at the intended
10813 * location. IOW, validation we got the __reserved[] size right.
10815 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10819 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10822 struct perf_pmu_events_attr *pmu_attr =
10823 container_of(attr, struct perf_pmu_events_attr, attr);
10825 if (pmu_attr->event_str)
10826 return sprintf(page, "%s\n", pmu_attr->event_str);
10830 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10832 static int __init perf_event_sysfs_init(void)
10837 mutex_lock(&pmus_lock);
10839 ret = bus_register(&pmu_bus);
10843 list_for_each_entry(pmu, &pmus, entry) {
10844 if (!pmu->name || pmu->type < 0)
10847 ret = pmu_dev_alloc(pmu);
10848 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10850 pmu_bus_running = 1;
10854 mutex_unlock(&pmus_lock);
10858 device_initcall(perf_event_sysfs_init);
10860 #ifdef CONFIG_CGROUP_PERF
10861 static struct cgroup_subsys_state *
10862 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10864 struct perf_cgroup *jc;
10866 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10868 return ERR_PTR(-ENOMEM);
10870 jc->info = alloc_percpu(struct perf_cgroup_info);
10873 return ERR_PTR(-ENOMEM);
10879 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10881 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10883 free_percpu(jc->info);
10887 static int __perf_cgroup_move(void *info)
10889 struct task_struct *task = info;
10891 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10896 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10898 struct task_struct *task;
10899 struct cgroup_subsys_state *css;
10901 cgroup_taskset_for_each(task, css, tset)
10902 task_function_call(task, __perf_cgroup_move, task);
10905 struct cgroup_subsys perf_event_cgrp_subsys = {
10906 .css_alloc = perf_cgroup_css_alloc,
10907 .css_free = perf_cgroup_css_free,
10908 .attach = perf_cgroup_attach,
10910 #endif /* CONFIG_CGROUP_PERF */