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)
1473 lockdep_assert_held(&ctx->lock);
1475 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1476 event->attach_state |= PERF_ATTACH_CONTEXT;
1479 * If we're a stand alone event or group leader, we go to the context
1480 * list, group events are kept attached to the group so that
1481 * perf_group_detach can, at all times, locate all siblings.
1483 if (event->group_leader == event) {
1484 struct list_head *list;
1486 event->group_caps = event->event_caps;
1488 list = ctx_group_list(event, ctx);
1489 list_add_tail(&event->group_entry, list);
1492 list_update_cgroup_event(event, ctx, true);
1494 list_add_rcu(&event->event_entry, &ctx->event_list);
1496 if (event->attr.inherit_stat)
1503 * Initialize event state based on the perf_event_attr::disabled.
1505 static inline void perf_event__state_init(struct perf_event *event)
1507 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1508 PERF_EVENT_STATE_INACTIVE;
1511 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1513 int entry = sizeof(u64); /* value */
1517 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1518 size += sizeof(u64);
1520 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1521 size += sizeof(u64);
1523 if (event->attr.read_format & PERF_FORMAT_ID)
1524 entry += sizeof(u64);
1526 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1528 size += sizeof(u64);
1532 event->read_size = size;
1535 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1537 struct perf_sample_data *data;
1540 if (sample_type & PERF_SAMPLE_IP)
1541 size += sizeof(data->ip);
1543 if (sample_type & PERF_SAMPLE_ADDR)
1544 size += sizeof(data->addr);
1546 if (sample_type & PERF_SAMPLE_PERIOD)
1547 size += sizeof(data->period);
1549 if (sample_type & PERF_SAMPLE_WEIGHT)
1550 size += sizeof(data->weight);
1552 if (sample_type & PERF_SAMPLE_READ)
1553 size += event->read_size;
1555 if (sample_type & PERF_SAMPLE_DATA_SRC)
1556 size += sizeof(data->data_src.val);
1558 if (sample_type & PERF_SAMPLE_TRANSACTION)
1559 size += sizeof(data->txn);
1561 event->header_size = size;
1565 * Called at perf_event creation and when events are attached/detached from a
1568 static void perf_event__header_size(struct perf_event *event)
1570 __perf_event_read_size(event,
1571 event->group_leader->nr_siblings);
1572 __perf_event_header_size(event, event->attr.sample_type);
1575 static void perf_event__id_header_size(struct perf_event *event)
1577 struct perf_sample_data *data;
1578 u64 sample_type = event->attr.sample_type;
1581 if (sample_type & PERF_SAMPLE_TID)
1582 size += sizeof(data->tid_entry);
1584 if (sample_type & PERF_SAMPLE_TIME)
1585 size += sizeof(data->time);
1587 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1588 size += sizeof(data->id);
1590 if (sample_type & PERF_SAMPLE_ID)
1591 size += sizeof(data->id);
1593 if (sample_type & PERF_SAMPLE_STREAM_ID)
1594 size += sizeof(data->stream_id);
1596 if (sample_type & PERF_SAMPLE_CPU)
1597 size += sizeof(data->cpu_entry);
1599 event->id_header_size = size;
1602 static bool perf_event_validate_size(struct perf_event *event)
1605 * The values computed here will be over-written when we actually
1608 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1609 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1610 perf_event__id_header_size(event);
1613 * Sum the lot; should not exceed the 64k limit we have on records.
1614 * Conservative limit to allow for callchains and other variable fields.
1616 if (event->read_size + event->header_size +
1617 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1623 static void perf_group_attach(struct perf_event *event)
1625 struct perf_event *group_leader = event->group_leader, *pos;
1628 * We can have double attach due to group movement in perf_event_open.
1630 if (event->attach_state & PERF_ATTACH_GROUP)
1633 event->attach_state |= PERF_ATTACH_GROUP;
1635 if (group_leader == event)
1638 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1640 group_leader->group_caps &= event->event_caps;
1642 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1643 group_leader->nr_siblings++;
1645 perf_event__header_size(group_leader);
1647 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1648 perf_event__header_size(pos);
1652 * Remove a event from the lists for its context.
1653 * Must be called with ctx->mutex and ctx->lock held.
1656 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1658 WARN_ON_ONCE(event->ctx != ctx);
1659 lockdep_assert_held(&ctx->lock);
1662 * We can have double detach due to exit/hot-unplug + close.
1664 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1667 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1669 list_update_cgroup_event(event, ctx, false);
1672 if (event->attr.inherit_stat)
1675 list_del_rcu(&event->event_entry);
1677 if (event->group_leader == event)
1678 list_del_init(&event->group_entry);
1680 update_group_times(event);
1683 * If event was in error state, then keep it
1684 * that way, otherwise bogus counts will be
1685 * returned on read(). The only way to get out
1686 * of error state is by explicit re-enabling
1689 if (event->state > PERF_EVENT_STATE_OFF)
1690 event->state = PERF_EVENT_STATE_OFF;
1695 static void perf_group_detach(struct perf_event *event)
1697 struct perf_event *sibling, *tmp;
1698 struct list_head *list = NULL;
1701 * We can have double detach due to exit/hot-unplug + close.
1703 if (!(event->attach_state & PERF_ATTACH_GROUP))
1706 event->attach_state &= ~PERF_ATTACH_GROUP;
1709 * If this is a sibling, remove it from its group.
1711 if (event->group_leader != event) {
1712 list_del_init(&event->group_entry);
1713 event->group_leader->nr_siblings--;
1717 if (!list_empty(&event->group_entry))
1718 list = &event->group_entry;
1721 * If this was a group event with sibling events then
1722 * upgrade the siblings to singleton events by adding them
1723 * to whatever list we are on.
1725 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1727 list_move_tail(&sibling->group_entry, list);
1728 sibling->group_leader = sibling;
1730 /* Inherit group flags from the previous leader */
1731 sibling->group_caps = event->group_caps;
1733 WARN_ON_ONCE(sibling->ctx != event->ctx);
1737 perf_event__header_size(event->group_leader);
1739 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1740 perf_event__header_size(tmp);
1743 static bool is_orphaned_event(struct perf_event *event)
1745 return event->state == PERF_EVENT_STATE_DEAD;
1748 static inline int __pmu_filter_match(struct perf_event *event)
1750 struct pmu *pmu = event->pmu;
1751 return pmu->filter_match ? pmu->filter_match(event) : 1;
1755 * Check whether we should attempt to schedule an event group based on
1756 * PMU-specific filtering. An event group can consist of HW and SW events,
1757 * potentially with a SW leader, so we must check all the filters, to
1758 * determine whether a group is schedulable:
1760 static inline int pmu_filter_match(struct perf_event *event)
1762 struct perf_event *child;
1764 if (!__pmu_filter_match(event))
1767 list_for_each_entry(child, &event->sibling_list, group_entry) {
1768 if (!__pmu_filter_match(child))
1776 event_filter_match(struct perf_event *event)
1778 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1779 perf_cgroup_match(event) && pmu_filter_match(event);
1783 event_sched_out(struct perf_event *event,
1784 struct perf_cpu_context *cpuctx,
1785 struct perf_event_context *ctx)
1787 u64 tstamp = perf_event_time(event);
1790 WARN_ON_ONCE(event->ctx != ctx);
1791 lockdep_assert_held(&ctx->lock);
1794 * An event which could not be activated because of
1795 * filter mismatch still needs to have its timings
1796 * maintained, otherwise bogus information is return
1797 * via read() for time_enabled, time_running:
1799 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1800 !event_filter_match(event)) {
1801 delta = tstamp - event->tstamp_stopped;
1802 event->tstamp_running += delta;
1803 event->tstamp_stopped = tstamp;
1806 if (event->state != PERF_EVENT_STATE_ACTIVE)
1809 perf_pmu_disable(event->pmu);
1811 event->tstamp_stopped = tstamp;
1812 event->pmu->del(event, 0);
1814 event->state = PERF_EVENT_STATE_INACTIVE;
1815 if (event->pending_disable) {
1816 event->pending_disable = 0;
1817 event->state = PERF_EVENT_STATE_OFF;
1820 if (!is_software_event(event))
1821 cpuctx->active_oncpu--;
1822 if (!--ctx->nr_active)
1823 perf_event_ctx_deactivate(ctx);
1824 if (event->attr.freq && event->attr.sample_freq)
1826 if (event->attr.exclusive || !cpuctx->active_oncpu)
1827 cpuctx->exclusive = 0;
1829 perf_pmu_enable(event->pmu);
1833 group_sched_out(struct perf_event *group_event,
1834 struct perf_cpu_context *cpuctx,
1835 struct perf_event_context *ctx)
1837 struct perf_event *event;
1838 int state = group_event->state;
1840 perf_pmu_disable(ctx->pmu);
1842 event_sched_out(group_event, cpuctx, ctx);
1845 * Schedule out siblings (if any):
1847 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1848 event_sched_out(event, cpuctx, ctx);
1850 perf_pmu_enable(ctx->pmu);
1852 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1853 cpuctx->exclusive = 0;
1856 #define DETACH_GROUP 0x01UL
1859 * Cross CPU call to remove a performance event
1861 * We disable the event on the hardware level first. After that we
1862 * remove it from the context list.
1865 __perf_remove_from_context(struct perf_event *event,
1866 struct perf_cpu_context *cpuctx,
1867 struct perf_event_context *ctx,
1870 unsigned long flags = (unsigned long)info;
1872 event_sched_out(event, cpuctx, ctx);
1873 if (flags & DETACH_GROUP)
1874 perf_group_detach(event);
1875 list_del_event(event, ctx);
1877 if (!ctx->nr_events && ctx->is_active) {
1880 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1881 cpuctx->task_ctx = NULL;
1887 * Remove the event from a task's (or a CPU's) list of events.
1889 * If event->ctx is a cloned context, callers must make sure that
1890 * every task struct that event->ctx->task could possibly point to
1891 * remains valid. This is OK when called from perf_release since
1892 * that only calls us on the top-level context, which can't be a clone.
1893 * When called from perf_event_exit_task, it's OK because the
1894 * context has been detached from its task.
1896 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1898 lockdep_assert_held(&event->ctx->mutex);
1900 event_function_call(event, __perf_remove_from_context, (void *)flags);
1904 * Cross CPU call to disable a performance event
1906 static void __perf_event_disable(struct perf_event *event,
1907 struct perf_cpu_context *cpuctx,
1908 struct perf_event_context *ctx,
1911 if (event->state < PERF_EVENT_STATE_INACTIVE)
1914 update_context_time(ctx);
1915 update_cgrp_time_from_event(event);
1916 update_group_times(event);
1917 if (event == event->group_leader)
1918 group_sched_out(event, cpuctx, ctx);
1920 event_sched_out(event, cpuctx, ctx);
1921 event->state = PERF_EVENT_STATE_OFF;
1927 * If event->ctx is a cloned context, callers must make sure that
1928 * every task struct that event->ctx->task could possibly point to
1929 * remains valid. This condition is satisifed when called through
1930 * perf_event_for_each_child or perf_event_for_each because they
1931 * hold the top-level event's child_mutex, so any descendant that
1932 * goes to exit will block in perf_event_exit_event().
1934 * When called from perf_pending_event it's OK because event->ctx
1935 * is the current context on this CPU and preemption is disabled,
1936 * hence we can't get into perf_event_task_sched_out for this context.
1938 static void _perf_event_disable(struct perf_event *event)
1940 struct perf_event_context *ctx = event->ctx;
1942 raw_spin_lock_irq(&ctx->lock);
1943 if (event->state <= PERF_EVENT_STATE_OFF) {
1944 raw_spin_unlock_irq(&ctx->lock);
1947 raw_spin_unlock_irq(&ctx->lock);
1949 event_function_call(event, __perf_event_disable, NULL);
1952 void perf_event_disable_local(struct perf_event *event)
1954 event_function_local(event, __perf_event_disable, NULL);
1958 * Strictly speaking kernel users cannot create groups and therefore this
1959 * interface does not need the perf_event_ctx_lock() magic.
1961 void perf_event_disable(struct perf_event *event)
1963 struct perf_event_context *ctx;
1965 ctx = perf_event_ctx_lock(event);
1966 _perf_event_disable(event);
1967 perf_event_ctx_unlock(event, ctx);
1969 EXPORT_SYMBOL_GPL(perf_event_disable);
1971 void perf_event_disable_inatomic(struct perf_event *event)
1973 event->pending_disable = 1;
1974 irq_work_queue(&event->pending);
1977 static void perf_set_shadow_time(struct perf_event *event,
1978 struct perf_event_context *ctx,
1982 * use the correct time source for the time snapshot
1984 * We could get by without this by leveraging the
1985 * fact that to get to this function, the caller
1986 * has most likely already called update_context_time()
1987 * and update_cgrp_time_xx() and thus both timestamp
1988 * are identical (or very close). Given that tstamp is,
1989 * already adjusted for cgroup, we could say that:
1990 * tstamp - ctx->timestamp
1992 * tstamp - cgrp->timestamp.
1994 * Then, in perf_output_read(), the calculation would
1995 * work with no changes because:
1996 * - event is guaranteed scheduled in
1997 * - no scheduled out in between
1998 * - thus the timestamp would be the same
2000 * But this is a bit hairy.
2002 * So instead, we have an explicit cgroup call to remain
2003 * within the time time source all along. We believe it
2004 * is cleaner and simpler to understand.
2006 if (is_cgroup_event(event))
2007 perf_cgroup_set_shadow_time(event, tstamp);
2009 event->shadow_ctx_time = tstamp - ctx->timestamp;
2012 #define MAX_INTERRUPTS (~0ULL)
2014 static void perf_log_throttle(struct perf_event *event, int enable);
2015 static void perf_log_itrace_start(struct perf_event *event);
2018 event_sched_in(struct perf_event *event,
2019 struct perf_cpu_context *cpuctx,
2020 struct perf_event_context *ctx)
2022 u64 tstamp = perf_event_time(event);
2025 lockdep_assert_held(&ctx->lock);
2027 if (event->state <= PERF_EVENT_STATE_OFF)
2030 WRITE_ONCE(event->oncpu, smp_processor_id());
2032 * Order event::oncpu write to happen before the ACTIVE state
2036 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2039 * Unthrottle events, since we scheduled we might have missed several
2040 * ticks already, also for a heavily scheduling task there is little
2041 * guarantee it'll get a tick in a timely manner.
2043 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2044 perf_log_throttle(event, 1);
2045 event->hw.interrupts = 0;
2049 * The new state must be visible before we turn it on in the hardware:
2053 perf_pmu_disable(event->pmu);
2055 perf_set_shadow_time(event, ctx, tstamp);
2057 perf_log_itrace_start(event);
2059 if (event->pmu->add(event, PERF_EF_START)) {
2060 event->state = PERF_EVENT_STATE_INACTIVE;
2066 event->tstamp_running += tstamp - event->tstamp_stopped;
2068 if (!is_software_event(event))
2069 cpuctx->active_oncpu++;
2070 if (!ctx->nr_active++)
2071 perf_event_ctx_activate(ctx);
2072 if (event->attr.freq && event->attr.sample_freq)
2075 if (event->attr.exclusive)
2076 cpuctx->exclusive = 1;
2079 perf_pmu_enable(event->pmu);
2085 group_sched_in(struct perf_event *group_event,
2086 struct perf_cpu_context *cpuctx,
2087 struct perf_event_context *ctx)
2089 struct perf_event *event, *partial_group = NULL;
2090 struct pmu *pmu = ctx->pmu;
2091 u64 now = ctx->time;
2092 bool simulate = false;
2094 if (group_event->state == PERF_EVENT_STATE_OFF)
2097 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2099 if (event_sched_in(group_event, cpuctx, ctx)) {
2100 pmu->cancel_txn(pmu);
2101 perf_mux_hrtimer_restart(cpuctx);
2106 * Schedule in siblings as one group (if any):
2108 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2109 if (event_sched_in(event, cpuctx, ctx)) {
2110 partial_group = event;
2115 if (!pmu->commit_txn(pmu))
2120 * Groups can be scheduled in as one unit only, so undo any
2121 * partial group before returning:
2122 * The events up to the failed event are scheduled out normally,
2123 * tstamp_stopped will be updated.
2125 * The failed events and the remaining siblings need to have
2126 * their timings updated as if they had gone thru event_sched_in()
2127 * and event_sched_out(). This is required to get consistent timings
2128 * across the group. This also takes care of the case where the group
2129 * could never be scheduled by ensuring tstamp_stopped is set to mark
2130 * the time the event was actually stopped, such that time delta
2131 * calculation in update_event_times() is correct.
2133 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2134 if (event == partial_group)
2138 event->tstamp_running += now - event->tstamp_stopped;
2139 event->tstamp_stopped = now;
2141 event_sched_out(event, cpuctx, ctx);
2144 event_sched_out(group_event, cpuctx, ctx);
2146 pmu->cancel_txn(pmu);
2148 perf_mux_hrtimer_restart(cpuctx);
2154 * Work out whether we can put this event group on the CPU now.
2156 static int group_can_go_on(struct perf_event *event,
2157 struct perf_cpu_context *cpuctx,
2161 * Groups consisting entirely of software events can always go on.
2163 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2166 * If an exclusive group is already on, no other hardware
2169 if (cpuctx->exclusive)
2172 * If this group is exclusive and there are already
2173 * events on the CPU, it can't go on.
2175 if (event->attr.exclusive && cpuctx->active_oncpu)
2178 * Otherwise, try to add it if all previous groups were able
2184 static void add_event_to_ctx(struct perf_event *event,
2185 struct perf_event_context *ctx)
2187 u64 tstamp = perf_event_time(event);
2189 list_add_event(event, ctx);
2190 perf_group_attach(event);
2191 event->tstamp_enabled = tstamp;
2192 event->tstamp_running = tstamp;
2193 event->tstamp_stopped = tstamp;
2196 static void ctx_sched_out(struct perf_event_context *ctx,
2197 struct perf_cpu_context *cpuctx,
2198 enum event_type_t event_type);
2200 ctx_sched_in(struct perf_event_context *ctx,
2201 struct perf_cpu_context *cpuctx,
2202 enum event_type_t event_type,
2203 struct task_struct *task);
2205 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2206 struct perf_event_context *ctx)
2208 if (!cpuctx->task_ctx)
2211 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2214 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2217 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2218 struct perf_event_context *ctx,
2219 struct task_struct *task)
2221 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2223 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2224 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2226 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2229 static void ctx_resched(struct perf_cpu_context *cpuctx,
2230 struct perf_event_context *task_ctx)
2232 perf_pmu_disable(cpuctx->ctx.pmu);
2234 task_ctx_sched_out(cpuctx, task_ctx);
2235 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2236 perf_event_sched_in(cpuctx, task_ctx, current);
2237 perf_pmu_enable(cpuctx->ctx.pmu);
2241 * Cross CPU call to install and enable a performance event
2243 * Very similar to remote_function() + event_function() but cannot assume that
2244 * things like ctx->is_active and cpuctx->task_ctx are set.
2246 static int __perf_install_in_context(void *info)
2248 struct perf_event *event = info;
2249 struct perf_event_context *ctx = event->ctx;
2250 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2251 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2252 bool reprogram = true;
2255 raw_spin_lock(&cpuctx->ctx.lock);
2257 raw_spin_lock(&ctx->lock);
2260 reprogram = (ctx->task == current);
2263 * If the task is running, it must be running on this CPU,
2264 * otherwise we cannot reprogram things.
2266 * If its not running, we don't care, ctx->lock will
2267 * serialize against it becoming runnable.
2269 if (task_curr(ctx->task) && !reprogram) {
2274 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2275 } else if (task_ctx) {
2276 raw_spin_lock(&task_ctx->lock);
2280 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2281 add_event_to_ctx(event, ctx);
2282 ctx_resched(cpuctx, task_ctx);
2284 add_event_to_ctx(event, ctx);
2288 perf_ctx_unlock(cpuctx, task_ctx);
2294 * Attach a performance event to a context.
2296 * Very similar to event_function_call, see comment there.
2299 perf_install_in_context(struct perf_event_context *ctx,
2300 struct perf_event *event,
2303 struct task_struct *task = READ_ONCE(ctx->task);
2305 lockdep_assert_held(&ctx->mutex);
2307 if (event->cpu != -1)
2311 * Ensures that if we can observe event->ctx, both the event and ctx
2312 * will be 'complete'. See perf_iterate_sb_cpu().
2314 smp_store_release(&event->ctx, ctx);
2317 cpu_function_call(cpu, __perf_install_in_context, event);
2322 * Should not happen, we validate the ctx is still alive before calling.
2324 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2328 * Installing events is tricky because we cannot rely on ctx->is_active
2329 * to be set in case this is the nr_events 0 -> 1 transition.
2331 * Instead we use task_curr(), which tells us if the task is running.
2332 * However, since we use task_curr() outside of rq::lock, we can race
2333 * against the actual state. This means the result can be wrong.
2335 * If we get a false positive, we retry, this is harmless.
2337 * If we get a false negative, things are complicated. If we are after
2338 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2339 * value must be correct. If we're before, it doesn't matter since
2340 * perf_event_context_sched_in() will program the counter.
2342 * However, this hinges on the remote context switch having observed
2343 * our task->perf_event_ctxp[] store, such that it will in fact take
2344 * ctx::lock in perf_event_context_sched_in().
2346 * We do this by task_function_call(), if the IPI fails to hit the task
2347 * we know any future context switch of task must see the
2348 * perf_event_ctpx[] store.
2352 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2353 * task_cpu() load, such that if the IPI then does not find the task
2354 * running, a future context switch of that task must observe the
2359 if (!task_function_call(task, __perf_install_in_context, event))
2362 raw_spin_lock_irq(&ctx->lock);
2364 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2366 * Cannot happen because we already checked above (which also
2367 * cannot happen), and we hold ctx->mutex, which serializes us
2368 * against perf_event_exit_task_context().
2370 raw_spin_unlock_irq(&ctx->lock);
2374 * If the task is not running, ctx->lock will avoid it becoming so,
2375 * thus we can safely install the event.
2377 if (task_curr(task)) {
2378 raw_spin_unlock_irq(&ctx->lock);
2381 add_event_to_ctx(event, ctx);
2382 raw_spin_unlock_irq(&ctx->lock);
2386 * Put a event into inactive state and update time fields.
2387 * Enabling the leader of a group effectively enables all
2388 * the group members that aren't explicitly disabled, so we
2389 * have to update their ->tstamp_enabled also.
2390 * Note: this works for group members as well as group leaders
2391 * since the non-leader members' sibling_lists will be empty.
2393 static void __perf_event_mark_enabled(struct perf_event *event)
2395 struct perf_event *sub;
2396 u64 tstamp = perf_event_time(event);
2398 event->state = PERF_EVENT_STATE_INACTIVE;
2399 event->tstamp_enabled = tstamp - event->total_time_enabled;
2400 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2401 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2402 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2407 * Cross CPU call to enable a performance event
2409 static void __perf_event_enable(struct perf_event *event,
2410 struct perf_cpu_context *cpuctx,
2411 struct perf_event_context *ctx,
2414 struct perf_event *leader = event->group_leader;
2415 struct perf_event_context *task_ctx;
2417 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2418 event->state <= PERF_EVENT_STATE_ERROR)
2422 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2424 __perf_event_mark_enabled(event);
2426 if (!ctx->is_active)
2429 if (!event_filter_match(event)) {
2430 if (is_cgroup_event(event))
2431 perf_cgroup_defer_enabled(event);
2432 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2437 * If the event is in a group and isn't the group leader,
2438 * then don't put it on unless the group is on.
2440 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2441 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2445 task_ctx = cpuctx->task_ctx;
2447 WARN_ON_ONCE(task_ctx != ctx);
2449 ctx_resched(cpuctx, task_ctx);
2455 * If event->ctx is a cloned context, callers must make sure that
2456 * every task struct that event->ctx->task could possibly point to
2457 * remains valid. This condition is satisfied when called through
2458 * perf_event_for_each_child or perf_event_for_each as described
2459 * for perf_event_disable.
2461 static void _perf_event_enable(struct perf_event *event)
2463 struct perf_event_context *ctx = event->ctx;
2465 raw_spin_lock_irq(&ctx->lock);
2466 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2467 event->state < PERF_EVENT_STATE_ERROR) {
2468 raw_spin_unlock_irq(&ctx->lock);
2473 * If the event is in error state, clear that first.
2475 * That way, if we see the event in error state below, we know that it
2476 * has gone back into error state, as distinct from the task having
2477 * been scheduled away before the cross-call arrived.
2479 if (event->state == PERF_EVENT_STATE_ERROR)
2480 event->state = PERF_EVENT_STATE_OFF;
2481 raw_spin_unlock_irq(&ctx->lock);
2483 event_function_call(event, __perf_event_enable, NULL);
2487 * See perf_event_disable();
2489 void perf_event_enable(struct perf_event *event)
2491 struct perf_event_context *ctx;
2493 ctx = perf_event_ctx_lock(event);
2494 _perf_event_enable(event);
2495 perf_event_ctx_unlock(event, ctx);
2497 EXPORT_SYMBOL_GPL(perf_event_enable);
2499 struct stop_event_data {
2500 struct perf_event *event;
2501 unsigned int restart;
2504 static int __perf_event_stop(void *info)
2506 struct stop_event_data *sd = info;
2507 struct perf_event *event = sd->event;
2509 /* if it's already INACTIVE, do nothing */
2510 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2513 /* matches smp_wmb() in event_sched_in() */
2517 * There is a window with interrupts enabled before we get here,
2518 * so we need to check again lest we try to stop another CPU's event.
2520 if (READ_ONCE(event->oncpu) != smp_processor_id())
2523 event->pmu->stop(event, PERF_EF_UPDATE);
2526 * May race with the actual stop (through perf_pmu_output_stop()),
2527 * but it is only used for events with AUX ring buffer, and such
2528 * events will refuse to restart because of rb::aux_mmap_count==0,
2529 * see comments in perf_aux_output_begin().
2531 * Since this is happening on a event-local CPU, no trace is lost
2535 event->pmu->start(event, 0);
2540 static int perf_event_stop(struct perf_event *event, int restart)
2542 struct stop_event_data sd = {
2549 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2552 /* matches smp_wmb() in event_sched_in() */
2556 * We only want to restart ACTIVE events, so if the event goes
2557 * inactive here (event->oncpu==-1), there's nothing more to do;
2558 * fall through with ret==-ENXIO.
2560 ret = cpu_function_call(READ_ONCE(event->oncpu),
2561 __perf_event_stop, &sd);
2562 } while (ret == -EAGAIN);
2568 * In order to contain the amount of racy and tricky in the address filter
2569 * configuration management, it is a two part process:
2571 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2572 * we update the addresses of corresponding vmas in
2573 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2574 * (p2) when an event is scheduled in (pmu::add), it calls
2575 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2576 * if the generation has changed since the previous call.
2578 * If (p1) happens while the event is active, we restart it to force (p2).
2580 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2581 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2583 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2584 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2586 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2589 void perf_event_addr_filters_sync(struct perf_event *event)
2591 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2593 if (!has_addr_filter(event))
2596 raw_spin_lock(&ifh->lock);
2597 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2598 event->pmu->addr_filters_sync(event);
2599 event->hw.addr_filters_gen = event->addr_filters_gen;
2601 raw_spin_unlock(&ifh->lock);
2603 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2605 static int _perf_event_refresh(struct perf_event *event, int refresh)
2608 * not supported on inherited events
2610 if (event->attr.inherit || !is_sampling_event(event))
2613 atomic_add(refresh, &event->event_limit);
2614 _perf_event_enable(event);
2620 * See perf_event_disable()
2622 int perf_event_refresh(struct perf_event *event, int refresh)
2624 struct perf_event_context *ctx;
2627 ctx = perf_event_ctx_lock(event);
2628 ret = _perf_event_refresh(event, refresh);
2629 perf_event_ctx_unlock(event, ctx);
2633 EXPORT_SYMBOL_GPL(perf_event_refresh);
2635 static void ctx_sched_out(struct perf_event_context *ctx,
2636 struct perf_cpu_context *cpuctx,
2637 enum event_type_t event_type)
2639 int is_active = ctx->is_active;
2640 struct perf_event *event;
2642 lockdep_assert_held(&ctx->lock);
2644 if (likely(!ctx->nr_events)) {
2646 * See __perf_remove_from_context().
2648 WARN_ON_ONCE(ctx->is_active);
2650 WARN_ON_ONCE(cpuctx->task_ctx);
2654 ctx->is_active &= ~event_type;
2655 if (!(ctx->is_active & EVENT_ALL))
2659 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2660 if (!ctx->is_active)
2661 cpuctx->task_ctx = NULL;
2665 * Always update time if it was set; not only when it changes.
2666 * Otherwise we can 'forget' to update time for any but the last
2667 * context we sched out. For example:
2669 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2670 * ctx_sched_out(.event_type = EVENT_PINNED)
2672 * would only update time for the pinned events.
2674 if (is_active & EVENT_TIME) {
2675 /* update (and stop) ctx time */
2676 update_context_time(ctx);
2677 update_cgrp_time_from_cpuctx(cpuctx);
2680 is_active ^= ctx->is_active; /* changed bits */
2682 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2685 perf_pmu_disable(ctx->pmu);
2686 if (is_active & EVENT_PINNED) {
2687 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2688 group_sched_out(event, cpuctx, ctx);
2691 if (is_active & EVENT_FLEXIBLE) {
2692 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2693 group_sched_out(event, cpuctx, ctx);
2695 perf_pmu_enable(ctx->pmu);
2699 * Test whether two contexts are equivalent, i.e. whether they have both been
2700 * cloned from the same version of the same context.
2702 * Equivalence is measured using a generation number in the context that is
2703 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2704 * and list_del_event().
2706 static int context_equiv(struct perf_event_context *ctx1,
2707 struct perf_event_context *ctx2)
2709 lockdep_assert_held(&ctx1->lock);
2710 lockdep_assert_held(&ctx2->lock);
2712 /* Pinning disables the swap optimization */
2713 if (ctx1->pin_count || ctx2->pin_count)
2716 /* If ctx1 is the parent of ctx2 */
2717 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2720 /* If ctx2 is the parent of ctx1 */
2721 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2725 * If ctx1 and ctx2 have the same parent; we flatten the parent
2726 * hierarchy, see perf_event_init_context().
2728 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2729 ctx1->parent_gen == ctx2->parent_gen)
2736 static void __perf_event_sync_stat(struct perf_event *event,
2737 struct perf_event *next_event)
2741 if (!event->attr.inherit_stat)
2745 * Update the event value, we cannot use perf_event_read()
2746 * because we're in the middle of a context switch and have IRQs
2747 * disabled, which upsets smp_call_function_single(), however
2748 * we know the event must be on the current CPU, therefore we
2749 * don't need to use it.
2751 switch (event->state) {
2752 case PERF_EVENT_STATE_ACTIVE:
2753 event->pmu->read(event);
2756 case PERF_EVENT_STATE_INACTIVE:
2757 update_event_times(event);
2765 * In order to keep per-task stats reliable we need to flip the event
2766 * values when we flip the contexts.
2768 value = local64_read(&next_event->count);
2769 value = local64_xchg(&event->count, value);
2770 local64_set(&next_event->count, value);
2772 swap(event->total_time_enabled, next_event->total_time_enabled);
2773 swap(event->total_time_running, next_event->total_time_running);
2776 * Since we swizzled the values, update the user visible data too.
2778 perf_event_update_userpage(event);
2779 perf_event_update_userpage(next_event);
2782 static void perf_event_sync_stat(struct perf_event_context *ctx,
2783 struct perf_event_context *next_ctx)
2785 struct perf_event *event, *next_event;
2790 update_context_time(ctx);
2792 event = list_first_entry(&ctx->event_list,
2793 struct perf_event, event_entry);
2795 next_event = list_first_entry(&next_ctx->event_list,
2796 struct perf_event, event_entry);
2798 while (&event->event_entry != &ctx->event_list &&
2799 &next_event->event_entry != &next_ctx->event_list) {
2801 __perf_event_sync_stat(event, next_event);
2803 event = list_next_entry(event, event_entry);
2804 next_event = list_next_entry(next_event, event_entry);
2808 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2809 struct task_struct *next)
2811 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2812 struct perf_event_context *next_ctx;
2813 struct perf_event_context *parent, *next_parent;
2814 struct perf_cpu_context *cpuctx;
2820 cpuctx = __get_cpu_context(ctx);
2821 if (!cpuctx->task_ctx)
2825 next_ctx = next->perf_event_ctxp[ctxn];
2829 parent = rcu_dereference(ctx->parent_ctx);
2830 next_parent = rcu_dereference(next_ctx->parent_ctx);
2832 /* If neither context have a parent context; they cannot be clones. */
2833 if (!parent && !next_parent)
2836 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2838 * Looks like the two contexts are clones, so we might be
2839 * able to optimize the context switch. We lock both
2840 * contexts and check that they are clones under the
2841 * lock (including re-checking that neither has been
2842 * uncloned in the meantime). It doesn't matter which
2843 * order we take the locks because no other cpu could
2844 * be trying to lock both of these tasks.
2846 raw_spin_lock(&ctx->lock);
2847 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2848 if (context_equiv(ctx, next_ctx)) {
2849 WRITE_ONCE(ctx->task, next);
2850 WRITE_ONCE(next_ctx->task, task);
2852 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2855 * RCU_INIT_POINTER here is safe because we've not
2856 * modified the ctx and the above modification of
2857 * ctx->task and ctx->task_ctx_data are immaterial
2858 * since those values are always verified under
2859 * ctx->lock which we're now holding.
2861 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2862 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2866 perf_event_sync_stat(ctx, next_ctx);
2868 raw_spin_unlock(&next_ctx->lock);
2869 raw_spin_unlock(&ctx->lock);
2875 raw_spin_lock(&ctx->lock);
2876 task_ctx_sched_out(cpuctx, ctx);
2877 raw_spin_unlock(&ctx->lock);
2881 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2883 void perf_sched_cb_dec(struct pmu *pmu)
2885 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2887 this_cpu_dec(perf_sched_cb_usages);
2889 if (!--cpuctx->sched_cb_usage)
2890 list_del(&cpuctx->sched_cb_entry);
2894 void perf_sched_cb_inc(struct pmu *pmu)
2896 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2898 if (!cpuctx->sched_cb_usage++)
2899 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2901 this_cpu_inc(perf_sched_cb_usages);
2905 * This function provides the context switch callback to the lower code
2906 * layer. It is invoked ONLY when the context switch callback is enabled.
2908 * This callback is relevant even to per-cpu events; for example multi event
2909 * PEBS requires this to provide PID/TID information. This requires we flush
2910 * all queued PEBS records before we context switch to a new task.
2912 static void perf_pmu_sched_task(struct task_struct *prev,
2913 struct task_struct *next,
2916 struct perf_cpu_context *cpuctx;
2922 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2923 pmu = cpuctx->unique_pmu; /* software PMUs will not have sched_task */
2925 if (WARN_ON_ONCE(!pmu->sched_task))
2928 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2929 perf_pmu_disable(pmu);
2931 pmu->sched_task(cpuctx->task_ctx, sched_in);
2933 perf_pmu_enable(pmu);
2934 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2938 static void perf_event_switch(struct task_struct *task,
2939 struct task_struct *next_prev, bool sched_in);
2941 #define for_each_task_context_nr(ctxn) \
2942 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2945 * Called from scheduler to remove the events of the current task,
2946 * with interrupts disabled.
2948 * We stop each event and update the event value in event->count.
2950 * This does not protect us against NMI, but disable()
2951 * sets the disabled bit in the control field of event _before_
2952 * accessing the event control register. If a NMI hits, then it will
2953 * not restart the event.
2955 void __perf_event_task_sched_out(struct task_struct *task,
2956 struct task_struct *next)
2960 if (__this_cpu_read(perf_sched_cb_usages))
2961 perf_pmu_sched_task(task, next, false);
2963 if (atomic_read(&nr_switch_events))
2964 perf_event_switch(task, next, false);
2966 for_each_task_context_nr(ctxn)
2967 perf_event_context_sched_out(task, ctxn, next);
2970 * if cgroup events exist on this CPU, then we need
2971 * to check if we have to switch out PMU state.
2972 * cgroup event are system-wide mode only
2974 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2975 perf_cgroup_sched_out(task, next);
2979 * Called with IRQs disabled
2981 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2982 enum event_type_t event_type)
2984 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2988 ctx_pinned_sched_in(struct perf_event_context *ctx,
2989 struct perf_cpu_context *cpuctx)
2991 struct perf_event *event;
2993 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2994 if (event->state <= PERF_EVENT_STATE_OFF)
2996 if (!event_filter_match(event))
2999 /* may need to reset tstamp_enabled */
3000 if (is_cgroup_event(event))
3001 perf_cgroup_mark_enabled(event, ctx);
3003 if (group_can_go_on(event, cpuctx, 1))
3004 group_sched_in(event, cpuctx, ctx);
3007 * If this pinned group hasn't been scheduled,
3008 * put it in error state.
3010 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3011 update_group_times(event);
3012 event->state = PERF_EVENT_STATE_ERROR;
3018 ctx_flexible_sched_in(struct perf_event_context *ctx,
3019 struct perf_cpu_context *cpuctx)
3021 struct perf_event *event;
3024 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3025 /* Ignore events in OFF or ERROR state */
3026 if (event->state <= PERF_EVENT_STATE_OFF)
3029 * Listen to the 'cpu' scheduling filter constraint
3032 if (!event_filter_match(event))
3035 /* may need to reset tstamp_enabled */
3036 if (is_cgroup_event(event))
3037 perf_cgroup_mark_enabled(event, ctx);
3039 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3040 if (group_sched_in(event, cpuctx, ctx))
3047 ctx_sched_in(struct perf_event_context *ctx,
3048 struct perf_cpu_context *cpuctx,
3049 enum event_type_t event_type,
3050 struct task_struct *task)
3052 int is_active = ctx->is_active;
3055 lockdep_assert_held(&ctx->lock);
3057 if (likely(!ctx->nr_events))
3060 ctx->is_active |= (event_type | EVENT_TIME);
3063 cpuctx->task_ctx = ctx;
3065 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3068 is_active ^= ctx->is_active; /* changed bits */
3070 if (is_active & EVENT_TIME) {
3071 /* start ctx time */
3073 ctx->timestamp = now;
3074 perf_cgroup_set_timestamp(task, ctx);
3078 * First go through the list and put on any pinned groups
3079 * in order to give them the best chance of going on.
3081 if (is_active & EVENT_PINNED)
3082 ctx_pinned_sched_in(ctx, cpuctx);
3084 /* Then walk through the lower prio flexible groups */
3085 if (is_active & EVENT_FLEXIBLE)
3086 ctx_flexible_sched_in(ctx, cpuctx);
3089 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3090 enum event_type_t event_type,
3091 struct task_struct *task)
3093 struct perf_event_context *ctx = &cpuctx->ctx;
3095 ctx_sched_in(ctx, cpuctx, event_type, task);
3098 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3099 struct task_struct *task)
3101 struct perf_cpu_context *cpuctx;
3103 cpuctx = __get_cpu_context(ctx);
3104 if (cpuctx->task_ctx == ctx)
3107 perf_ctx_lock(cpuctx, ctx);
3108 perf_pmu_disable(ctx->pmu);
3110 * We want to keep the following priority order:
3111 * cpu pinned (that don't need to move), task pinned,
3112 * cpu flexible, task flexible.
3114 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3115 perf_event_sched_in(cpuctx, ctx, task);
3116 perf_pmu_enable(ctx->pmu);
3117 perf_ctx_unlock(cpuctx, ctx);
3121 * Called from scheduler to add the events of the current task
3122 * with interrupts disabled.
3124 * We restore the event value and then enable it.
3126 * This does not protect us against NMI, but enable()
3127 * sets the enabled bit in the control field of event _before_
3128 * accessing the event control register. If a NMI hits, then it will
3129 * keep the event running.
3131 void __perf_event_task_sched_in(struct task_struct *prev,
3132 struct task_struct *task)
3134 struct perf_event_context *ctx;
3138 * If cgroup events exist on this CPU, then we need to check if we have
3139 * to switch in PMU state; cgroup event are system-wide mode only.
3141 * Since cgroup events are CPU events, we must schedule these in before
3142 * we schedule in the task events.
3144 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3145 perf_cgroup_sched_in(prev, task);
3147 for_each_task_context_nr(ctxn) {
3148 ctx = task->perf_event_ctxp[ctxn];
3152 perf_event_context_sched_in(ctx, task);
3155 if (atomic_read(&nr_switch_events))
3156 perf_event_switch(task, prev, true);
3158 if (__this_cpu_read(perf_sched_cb_usages))
3159 perf_pmu_sched_task(prev, task, true);
3162 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3164 u64 frequency = event->attr.sample_freq;
3165 u64 sec = NSEC_PER_SEC;
3166 u64 divisor, dividend;
3168 int count_fls, nsec_fls, frequency_fls, sec_fls;
3170 count_fls = fls64(count);
3171 nsec_fls = fls64(nsec);
3172 frequency_fls = fls64(frequency);
3176 * We got @count in @nsec, with a target of sample_freq HZ
3177 * the target period becomes:
3180 * period = -------------------
3181 * @nsec * sample_freq
3186 * Reduce accuracy by one bit such that @a and @b converge
3187 * to a similar magnitude.
3189 #define REDUCE_FLS(a, b) \
3191 if (a##_fls > b##_fls) { \
3201 * Reduce accuracy until either term fits in a u64, then proceed with
3202 * the other, so that finally we can do a u64/u64 division.
3204 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3205 REDUCE_FLS(nsec, frequency);
3206 REDUCE_FLS(sec, count);
3209 if (count_fls + sec_fls > 64) {
3210 divisor = nsec * frequency;
3212 while (count_fls + sec_fls > 64) {
3213 REDUCE_FLS(count, sec);
3217 dividend = count * sec;
3219 dividend = count * sec;
3221 while (nsec_fls + frequency_fls > 64) {
3222 REDUCE_FLS(nsec, frequency);
3226 divisor = nsec * frequency;
3232 return div64_u64(dividend, divisor);
3235 static DEFINE_PER_CPU(int, perf_throttled_count);
3236 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3238 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3240 struct hw_perf_event *hwc = &event->hw;
3241 s64 period, sample_period;
3244 period = perf_calculate_period(event, nsec, count);
3246 delta = (s64)(period - hwc->sample_period);
3247 delta = (delta + 7) / 8; /* low pass filter */
3249 sample_period = hwc->sample_period + delta;
3254 hwc->sample_period = sample_period;
3256 if (local64_read(&hwc->period_left) > 8*sample_period) {
3258 event->pmu->stop(event, PERF_EF_UPDATE);
3260 local64_set(&hwc->period_left, 0);
3263 event->pmu->start(event, PERF_EF_RELOAD);
3268 * combine freq adjustment with unthrottling to avoid two passes over the
3269 * events. At the same time, make sure, having freq events does not change
3270 * the rate of unthrottling as that would introduce bias.
3272 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3275 struct perf_event *event;
3276 struct hw_perf_event *hwc;
3277 u64 now, period = TICK_NSEC;
3281 * only need to iterate over all events iff:
3282 * - context have events in frequency mode (needs freq adjust)
3283 * - there are events to unthrottle on this cpu
3285 if (!(ctx->nr_freq || needs_unthr))
3288 raw_spin_lock(&ctx->lock);
3289 perf_pmu_disable(ctx->pmu);
3291 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3292 if (event->state != PERF_EVENT_STATE_ACTIVE)
3295 if (!event_filter_match(event))
3298 perf_pmu_disable(event->pmu);
3302 if (hwc->interrupts == MAX_INTERRUPTS) {
3303 hwc->interrupts = 0;
3304 perf_log_throttle(event, 1);
3305 event->pmu->start(event, 0);
3308 if (!event->attr.freq || !event->attr.sample_freq)
3312 * stop the event and update event->count
3314 event->pmu->stop(event, PERF_EF_UPDATE);
3316 now = local64_read(&event->count);
3317 delta = now - hwc->freq_count_stamp;
3318 hwc->freq_count_stamp = now;
3322 * reload only if value has changed
3323 * we have stopped the event so tell that
3324 * to perf_adjust_period() to avoid stopping it
3328 perf_adjust_period(event, period, delta, false);
3330 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3332 perf_pmu_enable(event->pmu);
3335 perf_pmu_enable(ctx->pmu);
3336 raw_spin_unlock(&ctx->lock);
3340 * Round-robin a context's events:
3342 static void rotate_ctx(struct perf_event_context *ctx)
3345 * Rotate the first entry last of non-pinned groups. Rotation might be
3346 * disabled by the inheritance code.
3348 if (!ctx->rotate_disable)
3349 list_rotate_left(&ctx->flexible_groups);
3352 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3354 struct perf_event_context *ctx = NULL;
3357 if (cpuctx->ctx.nr_events) {
3358 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3362 ctx = cpuctx->task_ctx;
3363 if (ctx && ctx->nr_events) {
3364 if (ctx->nr_events != ctx->nr_active)
3371 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3372 perf_pmu_disable(cpuctx->ctx.pmu);
3374 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3376 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3378 rotate_ctx(&cpuctx->ctx);
3382 perf_event_sched_in(cpuctx, ctx, current);
3384 perf_pmu_enable(cpuctx->ctx.pmu);
3385 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3391 void perf_event_task_tick(void)
3393 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3394 struct perf_event_context *ctx, *tmp;
3397 WARN_ON(!irqs_disabled());
3399 __this_cpu_inc(perf_throttled_seq);
3400 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3401 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3403 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3404 perf_adjust_freq_unthr_context(ctx, throttled);
3407 static int event_enable_on_exec(struct perf_event *event,
3408 struct perf_event_context *ctx)
3410 if (!event->attr.enable_on_exec)
3413 event->attr.enable_on_exec = 0;
3414 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3417 __perf_event_mark_enabled(event);
3423 * Enable all of a task's events that have been marked enable-on-exec.
3424 * This expects task == current.
3426 static void perf_event_enable_on_exec(int ctxn)
3428 struct perf_event_context *ctx, *clone_ctx = NULL;
3429 struct perf_cpu_context *cpuctx;
3430 struct perf_event *event;
3431 unsigned long flags;
3434 local_irq_save(flags);
3435 ctx = current->perf_event_ctxp[ctxn];
3436 if (!ctx || !ctx->nr_events)
3439 cpuctx = __get_cpu_context(ctx);
3440 perf_ctx_lock(cpuctx, ctx);
3441 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3442 list_for_each_entry(event, &ctx->event_list, event_entry)
3443 enabled |= event_enable_on_exec(event, ctx);
3446 * Unclone and reschedule this context if we enabled any event.
3449 clone_ctx = unclone_ctx(ctx);
3450 ctx_resched(cpuctx, ctx);
3452 perf_ctx_unlock(cpuctx, ctx);
3455 local_irq_restore(flags);
3461 struct perf_read_data {
3462 struct perf_event *event;
3467 static int find_cpu_to_read(struct perf_event *event, int local_cpu)
3469 int event_cpu = event->oncpu;
3470 u16 local_pkg, event_pkg;
3472 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3473 event_pkg = topology_physical_package_id(event_cpu);
3474 local_pkg = topology_physical_package_id(local_cpu);
3476 if (event_pkg == local_pkg)
3484 * Cross CPU call to read the hardware event
3486 static void __perf_event_read(void *info)
3488 struct perf_read_data *data = info;
3489 struct perf_event *sub, *event = data->event;
3490 struct perf_event_context *ctx = event->ctx;
3491 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3492 struct pmu *pmu = event->pmu;
3495 * If this is a task context, we need to check whether it is
3496 * the current task context of this cpu. If not it has been
3497 * scheduled out before the smp call arrived. In that case
3498 * event->count would have been updated to a recent sample
3499 * when the event was scheduled out.
3501 if (ctx->task && cpuctx->task_ctx != ctx)
3504 raw_spin_lock(&ctx->lock);
3505 if (ctx->is_active) {
3506 update_context_time(ctx);
3507 update_cgrp_time_from_event(event);
3510 update_event_times(event);
3511 if (event->state != PERF_EVENT_STATE_ACTIVE)
3520 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3524 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3525 update_event_times(sub);
3526 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3528 * Use sibling's PMU rather than @event's since
3529 * sibling could be on different (eg: software) PMU.
3531 sub->pmu->read(sub);
3535 data->ret = pmu->commit_txn(pmu);
3538 raw_spin_unlock(&ctx->lock);
3541 static inline u64 perf_event_count(struct perf_event *event)
3543 if (event->pmu->count)
3544 return event->pmu->count(event);
3546 return __perf_event_count(event);
3550 * NMI-safe method to read a local event, that is an event that
3552 * - either for the current task, or for this CPU
3553 * - does not have inherit set, for inherited task events
3554 * will not be local and we cannot read them atomically
3555 * - must not have a pmu::count method
3557 u64 perf_event_read_local(struct perf_event *event)
3559 unsigned long flags;
3563 * Disabling interrupts avoids all counter scheduling (context
3564 * switches, timer based rotation and IPIs).
3566 local_irq_save(flags);
3568 /* If this is a per-task event, it must be for current */
3569 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3570 event->hw.target != current);
3572 /* If this is a per-CPU event, it must be for this CPU */
3573 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3574 event->cpu != smp_processor_id());
3577 * It must not be an event with inherit set, we cannot read
3578 * all child counters from atomic context.
3580 WARN_ON_ONCE(event->attr.inherit);
3583 * It must not have a pmu::count method, those are not
3586 WARN_ON_ONCE(event->pmu->count);
3589 * If the event is currently on this CPU, its either a per-task event,
3590 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3593 if (event->oncpu == smp_processor_id())
3594 event->pmu->read(event);
3596 val = local64_read(&event->count);
3597 local_irq_restore(flags);
3602 static int perf_event_read(struct perf_event *event, bool group)
3604 int ret = 0, cpu_to_read, local_cpu;
3607 * If event is enabled and currently active on a CPU, update the
3608 * value in the event structure:
3610 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3611 struct perf_read_data data = {
3617 local_cpu = get_cpu();
3618 cpu_to_read = find_cpu_to_read(event, local_cpu);
3622 * Purposely ignore the smp_call_function_single() return
3625 * If event->oncpu isn't a valid CPU it means the event got
3626 * scheduled out and that will have updated the event count.
3628 * Therefore, either way, we'll have an up-to-date event count
3631 (void)smp_call_function_single(cpu_to_read, __perf_event_read, &data, 1);
3633 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3634 struct perf_event_context *ctx = event->ctx;
3635 unsigned long flags;
3637 raw_spin_lock_irqsave(&ctx->lock, flags);
3639 * may read while context is not active
3640 * (e.g., thread is blocked), in that case
3641 * we cannot update context time
3643 if (ctx->is_active) {
3644 update_context_time(ctx);
3645 update_cgrp_time_from_event(event);
3648 update_group_times(event);
3650 update_event_times(event);
3651 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3658 * Initialize the perf_event context in a task_struct:
3660 static void __perf_event_init_context(struct perf_event_context *ctx)
3662 raw_spin_lock_init(&ctx->lock);
3663 mutex_init(&ctx->mutex);
3664 INIT_LIST_HEAD(&ctx->active_ctx_list);
3665 INIT_LIST_HEAD(&ctx->pinned_groups);
3666 INIT_LIST_HEAD(&ctx->flexible_groups);
3667 INIT_LIST_HEAD(&ctx->event_list);
3668 atomic_set(&ctx->refcount, 1);
3671 static struct perf_event_context *
3672 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3674 struct perf_event_context *ctx;
3676 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3680 __perf_event_init_context(ctx);
3683 get_task_struct(task);
3690 static struct task_struct *
3691 find_lively_task_by_vpid(pid_t vpid)
3693 struct task_struct *task;
3699 task = find_task_by_vpid(vpid);
3701 get_task_struct(task);
3705 return ERR_PTR(-ESRCH);
3711 * Returns a matching context with refcount and pincount.
3713 static struct perf_event_context *
3714 find_get_context(struct pmu *pmu, struct task_struct *task,
3715 struct perf_event *event)
3717 struct perf_event_context *ctx, *clone_ctx = NULL;
3718 struct perf_cpu_context *cpuctx;
3719 void *task_ctx_data = NULL;
3720 unsigned long flags;
3722 int cpu = event->cpu;
3725 /* Must be root to operate on a CPU event: */
3726 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3727 return ERR_PTR(-EACCES);
3730 * We could be clever and allow to attach a event to an
3731 * offline CPU and activate it when the CPU comes up, but
3734 if (!cpu_online(cpu))
3735 return ERR_PTR(-ENODEV);
3737 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3746 ctxn = pmu->task_ctx_nr;
3750 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3751 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3752 if (!task_ctx_data) {
3759 ctx = perf_lock_task_context(task, ctxn, &flags);
3761 clone_ctx = unclone_ctx(ctx);
3764 if (task_ctx_data && !ctx->task_ctx_data) {
3765 ctx->task_ctx_data = task_ctx_data;
3766 task_ctx_data = NULL;
3768 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3773 ctx = alloc_perf_context(pmu, task);
3778 if (task_ctx_data) {
3779 ctx->task_ctx_data = task_ctx_data;
3780 task_ctx_data = NULL;
3784 mutex_lock(&task->perf_event_mutex);
3786 * If it has already passed perf_event_exit_task().
3787 * we must see PF_EXITING, it takes this mutex too.
3789 if (task->flags & PF_EXITING)
3791 else if (task->perf_event_ctxp[ctxn])
3796 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3798 mutex_unlock(&task->perf_event_mutex);
3800 if (unlikely(err)) {
3809 kfree(task_ctx_data);
3813 kfree(task_ctx_data);
3814 return ERR_PTR(err);
3817 static void perf_event_free_filter(struct perf_event *event);
3818 static void perf_event_free_bpf_prog(struct perf_event *event);
3820 static void free_event_rcu(struct rcu_head *head)
3822 struct perf_event *event;
3824 event = container_of(head, struct perf_event, rcu_head);
3826 put_pid_ns(event->ns);
3827 perf_event_free_filter(event);
3831 static void ring_buffer_attach(struct perf_event *event,
3832 struct ring_buffer *rb);
3834 static void detach_sb_event(struct perf_event *event)
3836 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3838 raw_spin_lock(&pel->lock);
3839 list_del_rcu(&event->sb_list);
3840 raw_spin_unlock(&pel->lock);
3843 static bool is_sb_event(struct perf_event *event)
3845 struct perf_event_attr *attr = &event->attr;
3850 if (event->attach_state & PERF_ATTACH_TASK)
3853 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3854 attr->comm || attr->comm_exec ||
3856 attr->context_switch)
3861 static void unaccount_pmu_sb_event(struct perf_event *event)
3863 if (is_sb_event(event))
3864 detach_sb_event(event);
3867 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3872 if (is_cgroup_event(event))
3873 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3876 #ifdef CONFIG_NO_HZ_FULL
3877 static DEFINE_SPINLOCK(nr_freq_lock);
3880 static void unaccount_freq_event_nohz(void)
3882 #ifdef CONFIG_NO_HZ_FULL
3883 spin_lock(&nr_freq_lock);
3884 if (atomic_dec_and_test(&nr_freq_events))
3885 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3886 spin_unlock(&nr_freq_lock);
3890 static void unaccount_freq_event(void)
3892 if (tick_nohz_full_enabled())
3893 unaccount_freq_event_nohz();
3895 atomic_dec(&nr_freq_events);
3898 static void unaccount_event(struct perf_event *event)
3905 if (event->attach_state & PERF_ATTACH_TASK)
3907 if (event->attr.mmap || event->attr.mmap_data)
3908 atomic_dec(&nr_mmap_events);
3909 if (event->attr.comm)
3910 atomic_dec(&nr_comm_events);
3911 if (event->attr.task)
3912 atomic_dec(&nr_task_events);
3913 if (event->attr.freq)
3914 unaccount_freq_event();
3915 if (event->attr.context_switch) {
3917 atomic_dec(&nr_switch_events);
3919 if (is_cgroup_event(event))
3921 if (has_branch_stack(event))
3925 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3926 schedule_delayed_work(&perf_sched_work, HZ);
3929 unaccount_event_cpu(event, event->cpu);
3931 unaccount_pmu_sb_event(event);
3934 static void perf_sched_delayed(struct work_struct *work)
3936 mutex_lock(&perf_sched_mutex);
3937 if (atomic_dec_and_test(&perf_sched_count))
3938 static_branch_disable(&perf_sched_events);
3939 mutex_unlock(&perf_sched_mutex);
3943 * The following implement mutual exclusion of events on "exclusive" pmus
3944 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3945 * at a time, so we disallow creating events that might conflict, namely:
3947 * 1) cpu-wide events in the presence of per-task events,
3948 * 2) per-task events in the presence of cpu-wide events,
3949 * 3) two matching events on the same context.
3951 * The former two cases are handled in the allocation path (perf_event_alloc(),
3952 * _free_event()), the latter -- before the first perf_install_in_context().
3954 static int exclusive_event_init(struct perf_event *event)
3956 struct pmu *pmu = event->pmu;
3958 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3962 * Prevent co-existence of per-task and cpu-wide events on the
3963 * same exclusive pmu.
3965 * Negative pmu::exclusive_cnt means there are cpu-wide
3966 * events on this "exclusive" pmu, positive means there are
3969 * Since this is called in perf_event_alloc() path, event::ctx
3970 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3971 * to mean "per-task event", because unlike other attach states it
3972 * never gets cleared.
3974 if (event->attach_state & PERF_ATTACH_TASK) {
3975 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3978 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3985 static void exclusive_event_destroy(struct perf_event *event)
3987 struct pmu *pmu = event->pmu;
3989 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3992 /* see comment in exclusive_event_init() */
3993 if (event->attach_state & PERF_ATTACH_TASK)
3994 atomic_dec(&pmu->exclusive_cnt);
3996 atomic_inc(&pmu->exclusive_cnt);
3999 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4001 if ((e1->pmu == e2->pmu) &&
4002 (e1->cpu == e2->cpu ||
4009 /* Called under the same ctx::mutex as perf_install_in_context() */
4010 static bool exclusive_event_installable(struct perf_event *event,
4011 struct perf_event_context *ctx)
4013 struct perf_event *iter_event;
4014 struct pmu *pmu = event->pmu;
4016 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4019 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4020 if (exclusive_event_match(iter_event, event))
4027 static void perf_addr_filters_splice(struct perf_event *event,
4028 struct list_head *head);
4030 static void _free_event(struct perf_event *event)
4032 irq_work_sync(&event->pending);
4034 unaccount_event(event);
4038 * Can happen when we close an event with re-directed output.
4040 * Since we have a 0 refcount, perf_mmap_close() will skip
4041 * over us; possibly making our ring_buffer_put() the last.
4043 mutex_lock(&event->mmap_mutex);
4044 ring_buffer_attach(event, NULL);
4045 mutex_unlock(&event->mmap_mutex);
4048 if (is_cgroup_event(event))
4049 perf_detach_cgroup(event);
4051 if (!event->parent) {
4052 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4053 put_callchain_buffers();
4056 perf_event_free_bpf_prog(event);
4057 perf_addr_filters_splice(event, NULL);
4058 kfree(event->addr_filters_offs);
4061 event->destroy(event);
4064 put_ctx(event->ctx);
4066 exclusive_event_destroy(event);
4067 module_put(event->pmu->module);
4069 call_rcu(&event->rcu_head, free_event_rcu);
4073 * Used to free events which have a known refcount of 1, such as in error paths
4074 * where the event isn't exposed yet and inherited events.
4076 static void free_event(struct perf_event *event)
4078 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4079 "unexpected event refcount: %ld; ptr=%p\n",
4080 atomic_long_read(&event->refcount), event)) {
4081 /* leak to avoid use-after-free */
4089 * Remove user event from the owner task.
4091 static void perf_remove_from_owner(struct perf_event *event)
4093 struct task_struct *owner;
4097 * Matches the smp_store_release() in perf_event_exit_task(). If we
4098 * observe !owner it means the list deletion is complete and we can
4099 * indeed free this event, otherwise we need to serialize on
4100 * owner->perf_event_mutex.
4102 owner = lockless_dereference(event->owner);
4105 * Since delayed_put_task_struct() also drops the last
4106 * task reference we can safely take a new reference
4107 * while holding the rcu_read_lock().
4109 get_task_struct(owner);
4115 * If we're here through perf_event_exit_task() we're already
4116 * holding ctx->mutex which would be an inversion wrt. the
4117 * normal lock order.
4119 * However we can safely take this lock because its the child
4122 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4125 * We have to re-check the event->owner field, if it is cleared
4126 * we raced with perf_event_exit_task(), acquiring the mutex
4127 * ensured they're done, and we can proceed with freeing the
4131 list_del_init(&event->owner_entry);
4132 smp_store_release(&event->owner, NULL);
4134 mutex_unlock(&owner->perf_event_mutex);
4135 put_task_struct(owner);
4139 static void put_event(struct perf_event *event)
4141 if (!atomic_long_dec_and_test(&event->refcount))
4148 * Kill an event dead; while event:refcount will preserve the event
4149 * object, it will not preserve its functionality. Once the last 'user'
4150 * gives up the object, we'll destroy the thing.
4152 int perf_event_release_kernel(struct perf_event *event)
4154 struct perf_event_context *ctx = event->ctx;
4155 struct perf_event *child, *tmp;
4158 * If we got here through err_file: fput(event_file); we will not have
4159 * attached to a context yet.
4162 WARN_ON_ONCE(event->attach_state &
4163 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4167 if (!is_kernel_event(event))
4168 perf_remove_from_owner(event);
4170 ctx = perf_event_ctx_lock(event);
4171 WARN_ON_ONCE(ctx->parent_ctx);
4172 perf_remove_from_context(event, DETACH_GROUP);
4174 raw_spin_lock_irq(&ctx->lock);
4176 * Mark this even as STATE_DEAD, there is no external reference to it
4179 * Anybody acquiring event->child_mutex after the below loop _must_
4180 * also see this, most importantly inherit_event() which will avoid
4181 * placing more children on the list.
4183 * Thus this guarantees that we will in fact observe and kill _ALL_
4186 event->state = PERF_EVENT_STATE_DEAD;
4187 raw_spin_unlock_irq(&ctx->lock);
4189 perf_event_ctx_unlock(event, ctx);
4192 mutex_lock(&event->child_mutex);
4193 list_for_each_entry(child, &event->child_list, child_list) {
4196 * Cannot change, child events are not migrated, see the
4197 * comment with perf_event_ctx_lock_nested().
4199 ctx = lockless_dereference(child->ctx);
4201 * Since child_mutex nests inside ctx::mutex, we must jump
4202 * through hoops. We start by grabbing a reference on the ctx.
4204 * Since the event cannot get freed while we hold the
4205 * child_mutex, the context must also exist and have a !0
4211 * Now that we have a ctx ref, we can drop child_mutex, and
4212 * acquire ctx::mutex without fear of it going away. Then we
4213 * can re-acquire child_mutex.
4215 mutex_unlock(&event->child_mutex);
4216 mutex_lock(&ctx->mutex);
4217 mutex_lock(&event->child_mutex);
4220 * Now that we hold ctx::mutex and child_mutex, revalidate our
4221 * state, if child is still the first entry, it didn't get freed
4222 * and we can continue doing so.
4224 tmp = list_first_entry_or_null(&event->child_list,
4225 struct perf_event, child_list);
4227 perf_remove_from_context(child, DETACH_GROUP);
4228 list_del(&child->child_list);
4231 * This matches the refcount bump in inherit_event();
4232 * this can't be the last reference.
4237 mutex_unlock(&event->child_mutex);
4238 mutex_unlock(&ctx->mutex);
4242 mutex_unlock(&event->child_mutex);
4245 put_event(event); /* Must be the 'last' reference */
4248 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4251 * Called when the last reference to the file is gone.
4253 static int perf_release(struct inode *inode, struct file *file)
4255 perf_event_release_kernel(file->private_data);
4259 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4261 struct perf_event *child;
4267 mutex_lock(&event->child_mutex);
4269 (void)perf_event_read(event, false);
4270 total += perf_event_count(event);
4272 *enabled += event->total_time_enabled +
4273 atomic64_read(&event->child_total_time_enabled);
4274 *running += event->total_time_running +
4275 atomic64_read(&event->child_total_time_running);
4277 list_for_each_entry(child, &event->child_list, child_list) {
4278 (void)perf_event_read(child, false);
4279 total += perf_event_count(child);
4280 *enabled += child->total_time_enabled;
4281 *running += child->total_time_running;
4283 mutex_unlock(&event->child_mutex);
4287 EXPORT_SYMBOL_GPL(perf_event_read_value);
4289 static int __perf_read_group_add(struct perf_event *leader,
4290 u64 read_format, u64 *values)
4292 struct perf_event *sub;
4293 int n = 1; /* skip @nr */
4296 ret = perf_event_read(leader, true);
4301 * Since we co-schedule groups, {enabled,running} times of siblings
4302 * will be identical to those of the leader, so we only publish one
4305 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4306 values[n++] += leader->total_time_enabled +
4307 atomic64_read(&leader->child_total_time_enabled);
4310 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4311 values[n++] += leader->total_time_running +
4312 atomic64_read(&leader->child_total_time_running);
4316 * Write {count,id} tuples for every sibling.
4318 values[n++] += perf_event_count(leader);
4319 if (read_format & PERF_FORMAT_ID)
4320 values[n++] = primary_event_id(leader);
4322 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4323 values[n++] += perf_event_count(sub);
4324 if (read_format & PERF_FORMAT_ID)
4325 values[n++] = primary_event_id(sub);
4331 static int perf_read_group(struct perf_event *event,
4332 u64 read_format, char __user *buf)
4334 struct perf_event *leader = event->group_leader, *child;
4335 struct perf_event_context *ctx = leader->ctx;
4339 lockdep_assert_held(&ctx->mutex);
4341 values = kzalloc(event->read_size, GFP_KERNEL);
4345 values[0] = 1 + leader->nr_siblings;
4348 * By locking the child_mutex of the leader we effectively
4349 * lock the child list of all siblings.. XXX explain how.
4351 mutex_lock(&leader->child_mutex);
4353 ret = __perf_read_group_add(leader, read_format, values);
4357 list_for_each_entry(child, &leader->child_list, child_list) {
4358 ret = __perf_read_group_add(child, read_format, values);
4363 mutex_unlock(&leader->child_mutex);
4365 ret = event->read_size;
4366 if (copy_to_user(buf, values, event->read_size))
4371 mutex_unlock(&leader->child_mutex);
4377 static int perf_read_one(struct perf_event *event,
4378 u64 read_format, char __user *buf)
4380 u64 enabled, running;
4384 values[n++] = perf_event_read_value(event, &enabled, &running);
4385 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4386 values[n++] = enabled;
4387 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4388 values[n++] = running;
4389 if (read_format & PERF_FORMAT_ID)
4390 values[n++] = primary_event_id(event);
4392 if (copy_to_user(buf, values, n * sizeof(u64)))
4395 return n * sizeof(u64);
4398 static bool is_event_hup(struct perf_event *event)
4402 if (event->state > PERF_EVENT_STATE_EXIT)
4405 mutex_lock(&event->child_mutex);
4406 no_children = list_empty(&event->child_list);
4407 mutex_unlock(&event->child_mutex);
4412 * Read the performance event - simple non blocking version for now
4415 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4417 u64 read_format = event->attr.read_format;
4421 * Return end-of-file for a read on a event that is in
4422 * error state (i.e. because it was pinned but it couldn't be
4423 * scheduled on to the CPU at some point).
4425 if (event->state == PERF_EVENT_STATE_ERROR)
4428 if (count < event->read_size)
4431 WARN_ON_ONCE(event->ctx->parent_ctx);
4432 if (read_format & PERF_FORMAT_GROUP)
4433 ret = perf_read_group(event, read_format, buf);
4435 ret = perf_read_one(event, read_format, buf);
4441 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4443 struct perf_event *event = file->private_data;
4444 struct perf_event_context *ctx;
4447 ctx = perf_event_ctx_lock(event);
4448 ret = __perf_read(event, buf, count);
4449 perf_event_ctx_unlock(event, ctx);
4454 static unsigned int perf_poll(struct file *file, poll_table *wait)
4456 struct perf_event *event = file->private_data;
4457 struct ring_buffer *rb;
4458 unsigned int events = POLLHUP;
4460 poll_wait(file, &event->waitq, wait);
4462 if (is_event_hup(event))
4466 * Pin the event->rb by taking event->mmap_mutex; otherwise
4467 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4469 mutex_lock(&event->mmap_mutex);
4472 events = atomic_xchg(&rb->poll, 0);
4473 mutex_unlock(&event->mmap_mutex);
4477 static void _perf_event_reset(struct perf_event *event)
4479 (void)perf_event_read(event, false);
4480 local64_set(&event->count, 0);
4481 perf_event_update_userpage(event);
4485 * Holding the top-level event's child_mutex means that any
4486 * descendant process that has inherited this event will block
4487 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4488 * task existence requirements of perf_event_enable/disable.
4490 static void perf_event_for_each_child(struct perf_event *event,
4491 void (*func)(struct perf_event *))
4493 struct perf_event *child;
4495 WARN_ON_ONCE(event->ctx->parent_ctx);
4497 mutex_lock(&event->child_mutex);
4499 list_for_each_entry(child, &event->child_list, child_list)
4501 mutex_unlock(&event->child_mutex);
4504 static void perf_event_for_each(struct perf_event *event,
4505 void (*func)(struct perf_event *))
4507 struct perf_event_context *ctx = event->ctx;
4508 struct perf_event *sibling;
4510 lockdep_assert_held(&ctx->mutex);
4512 event = event->group_leader;
4514 perf_event_for_each_child(event, func);
4515 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4516 perf_event_for_each_child(sibling, func);
4519 static void __perf_event_period(struct perf_event *event,
4520 struct perf_cpu_context *cpuctx,
4521 struct perf_event_context *ctx,
4524 u64 value = *((u64 *)info);
4527 if (event->attr.freq) {
4528 event->attr.sample_freq = value;
4530 event->attr.sample_period = value;
4531 event->hw.sample_period = value;
4534 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4536 perf_pmu_disable(ctx->pmu);
4538 * We could be throttled; unthrottle now to avoid the tick
4539 * trying to unthrottle while we already re-started the event.
4541 if (event->hw.interrupts == MAX_INTERRUPTS) {
4542 event->hw.interrupts = 0;
4543 perf_log_throttle(event, 1);
4545 event->pmu->stop(event, PERF_EF_UPDATE);
4548 local64_set(&event->hw.period_left, 0);
4551 event->pmu->start(event, PERF_EF_RELOAD);
4552 perf_pmu_enable(ctx->pmu);
4556 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4560 if (!is_sampling_event(event))
4563 if (copy_from_user(&value, arg, sizeof(value)))
4569 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4572 event_function_call(event, __perf_event_period, &value);
4577 static const struct file_operations perf_fops;
4579 static inline int perf_fget_light(int fd, struct fd *p)
4581 struct fd f = fdget(fd);
4585 if (f.file->f_op != &perf_fops) {
4593 static int perf_event_set_output(struct perf_event *event,
4594 struct perf_event *output_event);
4595 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4596 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4598 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4600 void (*func)(struct perf_event *);
4604 case PERF_EVENT_IOC_ENABLE:
4605 func = _perf_event_enable;
4607 case PERF_EVENT_IOC_DISABLE:
4608 func = _perf_event_disable;
4610 case PERF_EVENT_IOC_RESET:
4611 func = _perf_event_reset;
4614 case PERF_EVENT_IOC_REFRESH:
4615 return _perf_event_refresh(event, arg);
4617 case PERF_EVENT_IOC_PERIOD:
4618 return perf_event_period(event, (u64 __user *)arg);
4620 case PERF_EVENT_IOC_ID:
4622 u64 id = primary_event_id(event);
4624 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4629 case PERF_EVENT_IOC_SET_OUTPUT:
4633 struct perf_event *output_event;
4635 ret = perf_fget_light(arg, &output);
4638 output_event = output.file->private_data;
4639 ret = perf_event_set_output(event, output_event);
4642 ret = perf_event_set_output(event, NULL);
4647 case PERF_EVENT_IOC_SET_FILTER:
4648 return perf_event_set_filter(event, (void __user *)arg);
4650 case PERF_EVENT_IOC_SET_BPF:
4651 return perf_event_set_bpf_prog(event, arg);
4653 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4654 struct ring_buffer *rb;
4657 rb = rcu_dereference(event->rb);
4658 if (!rb || !rb->nr_pages) {
4662 rb_toggle_paused(rb, !!arg);
4670 if (flags & PERF_IOC_FLAG_GROUP)
4671 perf_event_for_each(event, func);
4673 perf_event_for_each_child(event, func);
4678 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4680 struct perf_event *event = file->private_data;
4681 struct perf_event_context *ctx;
4684 ctx = perf_event_ctx_lock(event);
4685 ret = _perf_ioctl(event, cmd, arg);
4686 perf_event_ctx_unlock(event, ctx);
4691 #ifdef CONFIG_COMPAT
4692 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4695 switch (_IOC_NR(cmd)) {
4696 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4697 case _IOC_NR(PERF_EVENT_IOC_ID):
4698 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4699 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4700 cmd &= ~IOCSIZE_MASK;
4701 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4705 return perf_ioctl(file, cmd, arg);
4708 # define perf_compat_ioctl NULL
4711 int perf_event_task_enable(void)
4713 struct perf_event_context *ctx;
4714 struct perf_event *event;
4716 mutex_lock(¤t->perf_event_mutex);
4717 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4718 ctx = perf_event_ctx_lock(event);
4719 perf_event_for_each_child(event, _perf_event_enable);
4720 perf_event_ctx_unlock(event, ctx);
4722 mutex_unlock(¤t->perf_event_mutex);
4727 int perf_event_task_disable(void)
4729 struct perf_event_context *ctx;
4730 struct perf_event *event;
4732 mutex_lock(¤t->perf_event_mutex);
4733 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4734 ctx = perf_event_ctx_lock(event);
4735 perf_event_for_each_child(event, _perf_event_disable);
4736 perf_event_ctx_unlock(event, ctx);
4738 mutex_unlock(¤t->perf_event_mutex);
4743 static int perf_event_index(struct perf_event *event)
4745 if (event->hw.state & PERF_HES_STOPPED)
4748 if (event->state != PERF_EVENT_STATE_ACTIVE)
4751 return event->pmu->event_idx(event);
4754 static void calc_timer_values(struct perf_event *event,
4761 *now = perf_clock();
4762 ctx_time = event->shadow_ctx_time + *now;
4763 *enabled = ctx_time - event->tstamp_enabled;
4764 *running = ctx_time - event->tstamp_running;
4767 static void perf_event_init_userpage(struct perf_event *event)
4769 struct perf_event_mmap_page *userpg;
4770 struct ring_buffer *rb;
4773 rb = rcu_dereference(event->rb);
4777 userpg = rb->user_page;
4779 /* Allow new userspace to detect that bit 0 is deprecated */
4780 userpg->cap_bit0_is_deprecated = 1;
4781 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4782 userpg->data_offset = PAGE_SIZE;
4783 userpg->data_size = perf_data_size(rb);
4789 void __weak arch_perf_update_userpage(
4790 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4795 * Callers need to ensure there can be no nesting of this function, otherwise
4796 * the seqlock logic goes bad. We can not serialize this because the arch
4797 * code calls this from NMI context.
4799 void perf_event_update_userpage(struct perf_event *event)
4801 struct perf_event_mmap_page *userpg;
4802 struct ring_buffer *rb;
4803 u64 enabled, running, now;
4806 rb = rcu_dereference(event->rb);
4811 * compute total_time_enabled, total_time_running
4812 * based on snapshot values taken when the event
4813 * was last scheduled in.
4815 * we cannot simply called update_context_time()
4816 * because of locking issue as we can be called in
4819 calc_timer_values(event, &now, &enabled, &running);
4821 userpg = rb->user_page;
4823 * Disable preemption so as to not let the corresponding user-space
4824 * spin too long if we get preempted.
4829 userpg->index = perf_event_index(event);
4830 userpg->offset = perf_event_count(event);
4832 userpg->offset -= local64_read(&event->hw.prev_count);
4834 userpg->time_enabled = enabled +
4835 atomic64_read(&event->child_total_time_enabled);
4837 userpg->time_running = running +
4838 atomic64_read(&event->child_total_time_running);
4840 arch_perf_update_userpage(event, userpg, now);
4849 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4851 struct perf_event *event = vma->vm_file->private_data;
4852 struct ring_buffer *rb;
4853 int ret = VM_FAULT_SIGBUS;
4855 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4856 if (vmf->pgoff == 0)
4862 rb = rcu_dereference(event->rb);
4866 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4869 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4873 get_page(vmf->page);
4874 vmf->page->mapping = vma->vm_file->f_mapping;
4875 vmf->page->index = vmf->pgoff;
4884 static void ring_buffer_attach(struct perf_event *event,
4885 struct ring_buffer *rb)
4887 struct ring_buffer *old_rb = NULL;
4888 unsigned long flags;
4892 * Should be impossible, we set this when removing
4893 * event->rb_entry and wait/clear when adding event->rb_entry.
4895 WARN_ON_ONCE(event->rcu_pending);
4898 spin_lock_irqsave(&old_rb->event_lock, flags);
4899 list_del_rcu(&event->rb_entry);
4900 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4902 event->rcu_batches = get_state_synchronize_rcu();
4903 event->rcu_pending = 1;
4907 if (event->rcu_pending) {
4908 cond_synchronize_rcu(event->rcu_batches);
4909 event->rcu_pending = 0;
4912 spin_lock_irqsave(&rb->event_lock, flags);
4913 list_add_rcu(&event->rb_entry, &rb->event_list);
4914 spin_unlock_irqrestore(&rb->event_lock, flags);
4918 * Avoid racing with perf_mmap_close(AUX): stop the event
4919 * before swizzling the event::rb pointer; if it's getting
4920 * unmapped, its aux_mmap_count will be 0 and it won't
4921 * restart. See the comment in __perf_pmu_output_stop().
4923 * Data will inevitably be lost when set_output is done in
4924 * mid-air, but then again, whoever does it like this is
4925 * not in for the data anyway.
4928 perf_event_stop(event, 0);
4930 rcu_assign_pointer(event->rb, rb);
4933 ring_buffer_put(old_rb);
4935 * Since we detached before setting the new rb, so that we
4936 * could attach the new rb, we could have missed a wakeup.
4939 wake_up_all(&event->waitq);
4943 static void ring_buffer_wakeup(struct perf_event *event)
4945 struct ring_buffer *rb;
4948 rb = rcu_dereference(event->rb);
4950 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4951 wake_up_all(&event->waitq);
4956 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4958 struct ring_buffer *rb;
4961 rb = rcu_dereference(event->rb);
4963 if (!atomic_inc_not_zero(&rb->refcount))
4971 void ring_buffer_put(struct ring_buffer *rb)
4973 if (!atomic_dec_and_test(&rb->refcount))
4976 WARN_ON_ONCE(!list_empty(&rb->event_list));
4978 call_rcu(&rb->rcu_head, rb_free_rcu);
4981 static void perf_mmap_open(struct vm_area_struct *vma)
4983 struct perf_event *event = vma->vm_file->private_data;
4985 atomic_inc(&event->mmap_count);
4986 atomic_inc(&event->rb->mmap_count);
4989 atomic_inc(&event->rb->aux_mmap_count);
4991 if (event->pmu->event_mapped)
4992 event->pmu->event_mapped(event);
4995 static void perf_pmu_output_stop(struct perf_event *event);
4998 * A buffer can be mmap()ed multiple times; either directly through the same
4999 * event, or through other events by use of perf_event_set_output().
5001 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5002 * the buffer here, where we still have a VM context. This means we need
5003 * to detach all events redirecting to us.
5005 static void perf_mmap_close(struct vm_area_struct *vma)
5007 struct perf_event *event = vma->vm_file->private_data;
5009 struct ring_buffer *rb = ring_buffer_get(event);
5010 struct user_struct *mmap_user = rb->mmap_user;
5011 int mmap_locked = rb->mmap_locked;
5012 unsigned long size = perf_data_size(rb);
5014 if (event->pmu->event_unmapped)
5015 event->pmu->event_unmapped(event);
5018 * rb->aux_mmap_count will always drop before rb->mmap_count and
5019 * event->mmap_count, so it is ok to use event->mmap_mutex to
5020 * serialize with perf_mmap here.
5022 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5023 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5025 * Stop all AUX events that are writing to this buffer,
5026 * so that we can free its AUX pages and corresponding PMU
5027 * data. Note that after rb::aux_mmap_count dropped to zero,
5028 * they won't start any more (see perf_aux_output_begin()).
5030 perf_pmu_output_stop(event);
5032 /* now it's safe to free the pages */
5033 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5034 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5036 /* this has to be the last one */
5038 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5040 mutex_unlock(&event->mmap_mutex);
5043 atomic_dec(&rb->mmap_count);
5045 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5048 ring_buffer_attach(event, NULL);
5049 mutex_unlock(&event->mmap_mutex);
5051 /* If there's still other mmap()s of this buffer, we're done. */
5052 if (atomic_read(&rb->mmap_count))
5056 * No other mmap()s, detach from all other events that might redirect
5057 * into the now unreachable buffer. Somewhat complicated by the
5058 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5062 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5063 if (!atomic_long_inc_not_zero(&event->refcount)) {
5065 * This event is en-route to free_event() which will
5066 * detach it and remove it from the list.
5072 mutex_lock(&event->mmap_mutex);
5074 * Check we didn't race with perf_event_set_output() which can
5075 * swizzle the rb from under us while we were waiting to
5076 * acquire mmap_mutex.
5078 * If we find a different rb; ignore this event, a next
5079 * iteration will no longer find it on the list. We have to
5080 * still restart the iteration to make sure we're not now
5081 * iterating the wrong list.
5083 if (event->rb == rb)
5084 ring_buffer_attach(event, NULL);
5086 mutex_unlock(&event->mmap_mutex);
5090 * Restart the iteration; either we're on the wrong list or
5091 * destroyed its integrity by doing a deletion.
5098 * It could be there's still a few 0-ref events on the list; they'll
5099 * get cleaned up by free_event() -- they'll also still have their
5100 * ref on the rb and will free it whenever they are done with it.
5102 * Aside from that, this buffer is 'fully' detached and unmapped,
5103 * undo the VM accounting.
5106 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5107 vma->vm_mm->pinned_vm -= mmap_locked;
5108 free_uid(mmap_user);
5111 ring_buffer_put(rb); /* could be last */
5114 static const struct vm_operations_struct perf_mmap_vmops = {
5115 .open = perf_mmap_open,
5116 .close = perf_mmap_close, /* non mergable */
5117 .fault = perf_mmap_fault,
5118 .page_mkwrite = perf_mmap_fault,
5121 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5123 struct perf_event *event = file->private_data;
5124 unsigned long user_locked, user_lock_limit;
5125 struct user_struct *user = current_user();
5126 unsigned long locked, lock_limit;
5127 struct ring_buffer *rb = NULL;
5128 unsigned long vma_size;
5129 unsigned long nr_pages;
5130 long user_extra = 0, extra = 0;
5131 int ret = 0, flags = 0;
5134 * Don't allow mmap() of inherited per-task counters. This would
5135 * create a performance issue due to all children writing to the
5138 if (event->cpu == -1 && event->attr.inherit)
5141 if (!(vma->vm_flags & VM_SHARED))
5144 vma_size = vma->vm_end - vma->vm_start;
5146 if (vma->vm_pgoff == 0) {
5147 nr_pages = (vma_size / PAGE_SIZE) - 1;
5150 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5151 * mapped, all subsequent mappings should have the same size
5152 * and offset. Must be above the normal perf buffer.
5154 u64 aux_offset, aux_size;
5159 nr_pages = vma_size / PAGE_SIZE;
5161 mutex_lock(&event->mmap_mutex);
5168 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5169 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5171 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5174 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5177 /* already mapped with a different offset */
5178 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5181 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5184 /* already mapped with a different size */
5185 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5188 if (!is_power_of_2(nr_pages))
5191 if (!atomic_inc_not_zero(&rb->mmap_count))
5194 if (rb_has_aux(rb)) {
5195 atomic_inc(&rb->aux_mmap_count);
5200 atomic_set(&rb->aux_mmap_count, 1);
5201 user_extra = nr_pages;
5207 * If we have rb pages ensure they're a power-of-two number, so we
5208 * can do bitmasks instead of modulo.
5210 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5213 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5216 WARN_ON_ONCE(event->ctx->parent_ctx);
5218 mutex_lock(&event->mmap_mutex);
5220 if (event->rb->nr_pages != nr_pages) {
5225 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5227 * Raced against perf_mmap_close() through
5228 * perf_event_set_output(). Try again, hope for better
5231 mutex_unlock(&event->mmap_mutex);
5238 user_extra = nr_pages + 1;
5241 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5244 * Increase the limit linearly with more CPUs:
5246 user_lock_limit *= num_online_cpus();
5248 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5250 if (user_locked > user_lock_limit)
5251 extra = user_locked - user_lock_limit;
5253 lock_limit = rlimit(RLIMIT_MEMLOCK);
5254 lock_limit >>= PAGE_SHIFT;
5255 locked = vma->vm_mm->pinned_vm + extra;
5257 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5258 !capable(CAP_IPC_LOCK)) {
5263 WARN_ON(!rb && event->rb);
5265 if (vma->vm_flags & VM_WRITE)
5266 flags |= RING_BUFFER_WRITABLE;
5269 rb = rb_alloc(nr_pages,
5270 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5278 atomic_set(&rb->mmap_count, 1);
5279 rb->mmap_user = get_current_user();
5280 rb->mmap_locked = extra;
5282 ring_buffer_attach(event, rb);
5284 perf_event_init_userpage(event);
5285 perf_event_update_userpage(event);
5287 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5288 event->attr.aux_watermark, flags);
5290 rb->aux_mmap_locked = extra;
5295 atomic_long_add(user_extra, &user->locked_vm);
5296 vma->vm_mm->pinned_vm += extra;
5298 atomic_inc(&event->mmap_count);
5300 atomic_dec(&rb->mmap_count);
5303 mutex_unlock(&event->mmap_mutex);
5306 * Since pinned accounting is per vm we cannot allow fork() to copy our
5309 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5310 vma->vm_ops = &perf_mmap_vmops;
5312 if (event->pmu->event_mapped)
5313 event->pmu->event_mapped(event);
5318 static int perf_fasync(int fd, struct file *filp, int on)
5320 struct inode *inode = file_inode(filp);
5321 struct perf_event *event = filp->private_data;
5325 retval = fasync_helper(fd, filp, on, &event->fasync);
5326 inode_unlock(inode);
5334 static const struct file_operations perf_fops = {
5335 .llseek = no_llseek,
5336 .release = perf_release,
5339 .unlocked_ioctl = perf_ioctl,
5340 .compat_ioctl = perf_compat_ioctl,
5342 .fasync = perf_fasync,
5348 * If there's data, ensure we set the poll() state and publish everything
5349 * to user-space before waking everybody up.
5352 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5354 /* only the parent has fasync state */
5356 event = event->parent;
5357 return &event->fasync;
5360 void perf_event_wakeup(struct perf_event *event)
5362 ring_buffer_wakeup(event);
5364 if (event->pending_kill) {
5365 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5366 event->pending_kill = 0;
5370 static void perf_pending_event(struct irq_work *entry)
5372 struct perf_event *event = container_of(entry,
5373 struct perf_event, pending);
5376 rctx = perf_swevent_get_recursion_context();
5378 * If we 'fail' here, that's OK, it means recursion is already disabled
5379 * and we won't recurse 'further'.
5382 if (event->pending_disable) {
5383 event->pending_disable = 0;
5384 perf_event_disable_local(event);
5387 if (event->pending_wakeup) {
5388 event->pending_wakeup = 0;
5389 perf_event_wakeup(event);
5393 perf_swevent_put_recursion_context(rctx);
5397 * We assume there is only KVM supporting the callbacks.
5398 * Later on, we might change it to a list if there is
5399 * another virtualization implementation supporting the callbacks.
5401 struct perf_guest_info_callbacks *perf_guest_cbs;
5403 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5405 perf_guest_cbs = cbs;
5408 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5410 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5412 perf_guest_cbs = NULL;
5415 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5418 perf_output_sample_regs(struct perf_output_handle *handle,
5419 struct pt_regs *regs, u64 mask)
5422 DECLARE_BITMAP(_mask, 64);
5424 bitmap_from_u64(_mask, mask);
5425 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5428 val = perf_reg_value(regs, bit);
5429 perf_output_put(handle, val);
5433 static void perf_sample_regs_user(struct perf_regs *regs_user,
5434 struct pt_regs *regs,
5435 struct pt_regs *regs_user_copy)
5437 if (user_mode(regs)) {
5438 regs_user->abi = perf_reg_abi(current);
5439 regs_user->regs = regs;
5440 } else if (current->mm) {
5441 perf_get_regs_user(regs_user, regs, regs_user_copy);
5443 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5444 regs_user->regs = NULL;
5448 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5449 struct pt_regs *regs)
5451 regs_intr->regs = regs;
5452 regs_intr->abi = perf_reg_abi(current);
5457 * Get remaining task size from user stack pointer.
5459 * It'd be better to take stack vma map and limit this more
5460 * precisly, but there's no way to get it safely under interrupt,
5461 * so using TASK_SIZE as limit.
5463 static u64 perf_ustack_task_size(struct pt_regs *regs)
5465 unsigned long addr = perf_user_stack_pointer(regs);
5467 if (!addr || addr >= TASK_SIZE)
5470 return TASK_SIZE - addr;
5474 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5475 struct pt_regs *regs)
5479 /* No regs, no stack pointer, no dump. */
5484 * Check if we fit in with the requested stack size into the:
5486 * If we don't, we limit the size to the TASK_SIZE.
5488 * - remaining sample size
5489 * If we don't, we customize the stack size to
5490 * fit in to the remaining sample size.
5493 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5494 stack_size = min(stack_size, (u16) task_size);
5496 /* Current header size plus static size and dynamic size. */
5497 header_size += 2 * sizeof(u64);
5499 /* Do we fit in with the current stack dump size? */
5500 if ((u16) (header_size + stack_size) < header_size) {
5502 * If we overflow the maximum size for the sample,
5503 * we customize the stack dump size to fit in.
5505 stack_size = USHRT_MAX - header_size - sizeof(u64);
5506 stack_size = round_up(stack_size, sizeof(u64));
5513 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5514 struct pt_regs *regs)
5516 /* Case of a kernel thread, nothing to dump */
5519 perf_output_put(handle, size);
5528 * - the size requested by user or the best one we can fit
5529 * in to the sample max size
5531 * - user stack dump data
5533 * - the actual dumped size
5537 perf_output_put(handle, dump_size);
5540 sp = perf_user_stack_pointer(regs);
5541 rem = __output_copy_user(handle, (void *) sp, dump_size);
5542 dyn_size = dump_size - rem;
5544 perf_output_skip(handle, rem);
5547 perf_output_put(handle, dyn_size);
5551 static void __perf_event_header__init_id(struct perf_event_header *header,
5552 struct perf_sample_data *data,
5553 struct perf_event *event)
5555 u64 sample_type = event->attr.sample_type;
5557 data->type = sample_type;
5558 header->size += event->id_header_size;
5560 if (sample_type & PERF_SAMPLE_TID) {
5561 /* namespace issues */
5562 data->tid_entry.pid = perf_event_pid(event, current);
5563 data->tid_entry.tid = perf_event_tid(event, current);
5566 if (sample_type & PERF_SAMPLE_TIME)
5567 data->time = perf_event_clock(event);
5569 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5570 data->id = primary_event_id(event);
5572 if (sample_type & PERF_SAMPLE_STREAM_ID)
5573 data->stream_id = event->id;
5575 if (sample_type & PERF_SAMPLE_CPU) {
5576 data->cpu_entry.cpu = raw_smp_processor_id();
5577 data->cpu_entry.reserved = 0;
5581 void perf_event_header__init_id(struct perf_event_header *header,
5582 struct perf_sample_data *data,
5583 struct perf_event *event)
5585 if (event->attr.sample_id_all)
5586 __perf_event_header__init_id(header, data, event);
5589 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5590 struct perf_sample_data *data)
5592 u64 sample_type = data->type;
5594 if (sample_type & PERF_SAMPLE_TID)
5595 perf_output_put(handle, data->tid_entry);
5597 if (sample_type & PERF_SAMPLE_TIME)
5598 perf_output_put(handle, data->time);
5600 if (sample_type & PERF_SAMPLE_ID)
5601 perf_output_put(handle, data->id);
5603 if (sample_type & PERF_SAMPLE_STREAM_ID)
5604 perf_output_put(handle, data->stream_id);
5606 if (sample_type & PERF_SAMPLE_CPU)
5607 perf_output_put(handle, data->cpu_entry);
5609 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5610 perf_output_put(handle, data->id);
5613 void perf_event__output_id_sample(struct perf_event *event,
5614 struct perf_output_handle *handle,
5615 struct perf_sample_data *sample)
5617 if (event->attr.sample_id_all)
5618 __perf_event__output_id_sample(handle, sample);
5621 static void perf_output_read_one(struct perf_output_handle *handle,
5622 struct perf_event *event,
5623 u64 enabled, u64 running)
5625 u64 read_format = event->attr.read_format;
5629 values[n++] = perf_event_count(event);
5630 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5631 values[n++] = enabled +
5632 atomic64_read(&event->child_total_time_enabled);
5634 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5635 values[n++] = running +
5636 atomic64_read(&event->child_total_time_running);
5638 if (read_format & PERF_FORMAT_ID)
5639 values[n++] = primary_event_id(event);
5641 __output_copy(handle, values, n * sizeof(u64));
5645 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5647 static void perf_output_read_group(struct perf_output_handle *handle,
5648 struct perf_event *event,
5649 u64 enabled, u64 running)
5651 struct perf_event *leader = event->group_leader, *sub;
5652 u64 read_format = event->attr.read_format;
5656 values[n++] = 1 + leader->nr_siblings;
5658 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5659 values[n++] = enabled;
5661 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5662 values[n++] = running;
5664 if (leader != event)
5665 leader->pmu->read(leader);
5667 values[n++] = perf_event_count(leader);
5668 if (read_format & PERF_FORMAT_ID)
5669 values[n++] = primary_event_id(leader);
5671 __output_copy(handle, values, n * sizeof(u64));
5673 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5676 if ((sub != event) &&
5677 (sub->state == PERF_EVENT_STATE_ACTIVE))
5678 sub->pmu->read(sub);
5680 values[n++] = perf_event_count(sub);
5681 if (read_format & PERF_FORMAT_ID)
5682 values[n++] = primary_event_id(sub);
5684 __output_copy(handle, values, n * sizeof(u64));
5688 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5689 PERF_FORMAT_TOTAL_TIME_RUNNING)
5691 static void perf_output_read(struct perf_output_handle *handle,
5692 struct perf_event *event)
5694 u64 enabled = 0, running = 0, now;
5695 u64 read_format = event->attr.read_format;
5698 * compute total_time_enabled, total_time_running
5699 * based on snapshot values taken when the event
5700 * was last scheduled in.
5702 * we cannot simply called update_context_time()
5703 * because of locking issue as we are called in
5706 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5707 calc_timer_values(event, &now, &enabled, &running);
5709 if (event->attr.read_format & PERF_FORMAT_GROUP)
5710 perf_output_read_group(handle, event, enabled, running);
5712 perf_output_read_one(handle, event, enabled, running);
5715 void perf_output_sample(struct perf_output_handle *handle,
5716 struct perf_event_header *header,
5717 struct perf_sample_data *data,
5718 struct perf_event *event)
5720 u64 sample_type = data->type;
5722 perf_output_put(handle, *header);
5724 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5725 perf_output_put(handle, data->id);
5727 if (sample_type & PERF_SAMPLE_IP)
5728 perf_output_put(handle, data->ip);
5730 if (sample_type & PERF_SAMPLE_TID)
5731 perf_output_put(handle, data->tid_entry);
5733 if (sample_type & PERF_SAMPLE_TIME)
5734 perf_output_put(handle, data->time);
5736 if (sample_type & PERF_SAMPLE_ADDR)
5737 perf_output_put(handle, data->addr);
5739 if (sample_type & PERF_SAMPLE_ID)
5740 perf_output_put(handle, data->id);
5742 if (sample_type & PERF_SAMPLE_STREAM_ID)
5743 perf_output_put(handle, data->stream_id);
5745 if (sample_type & PERF_SAMPLE_CPU)
5746 perf_output_put(handle, data->cpu_entry);
5748 if (sample_type & PERF_SAMPLE_PERIOD)
5749 perf_output_put(handle, data->period);
5751 if (sample_type & PERF_SAMPLE_READ)
5752 perf_output_read(handle, event);
5754 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5755 if (data->callchain) {
5758 if (data->callchain)
5759 size += data->callchain->nr;
5761 size *= sizeof(u64);
5763 __output_copy(handle, data->callchain, size);
5766 perf_output_put(handle, nr);
5770 if (sample_type & PERF_SAMPLE_RAW) {
5771 struct perf_raw_record *raw = data->raw;
5774 struct perf_raw_frag *frag = &raw->frag;
5776 perf_output_put(handle, raw->size);
5779 __output_custom(handle, frag->copy,
5780 frag->data, frag->size);
5782 __output_copy(handle, frag->data,
5785 if (perf_raw_frag_last(frag))
5790 __output_skip(handle, NULL, frag->pad);
5796 .size = sizeof(u32),
5799 perf_output_put(handle, raw);
5803 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5804 if (data->br_stack) {
5807 size = data->br_stack->nr
5808 * sizeof(struct perf_branch_entry);
5810 perf_output_put(handle, data->br_stack->nr);
5811 perf_output_copy(handle, data->br_stack->entries, size);
5814 * we always store at least the value of nr
5817 perf_output_put(handle, nr);
5821 if (sample_type & PERF_SAMPLE_REGS_USER) {
5822 u64 abi = data->regs_user.abi;
5825 * If there are no regs to dump, notice it through
5826 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5828 perf_output_put(handle, abi);
5831 u64 mask = event->attr.sample_regs_user;
5832 perf_output_sample_regs(handle,
5833 data->regs_user.regs,
5838 if (sample_type & PERF_SAMPLE_STACK_USER) {
5839 perf_output_sample_ustack(handle,
5840 data->stack_user_size,
5841 data->regs_user.regs);
5844 if (sample_type & PERF_SAMPLE_WEIGHT)
5845 perf_output_put(handle, data->weight);
5847 if (sample_type & PERF_SAMPLE_DATA_SRC)
5848 perf_output_put(handle, data->data_src.val);
5850 if (sample_type & PERF_SAMPLE_TRANSACTION)
5851 perf_output_put(handle, data->txn);
5853 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5854 u64 abi = data->regs_intr.abi;
5856 * If there are no regs to dump, notice it through
5857 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5859 perf_output_put(handle, abi);
5862 u64 mask = event->attr.sample_regs_intr;
5864 perf_output_sample_regs(handle,
5865 data->regs_intr.regs,
5870 if (!event->attr.watermark) {
5871 int wakeup_events = event->attr.wakeup_events;
5873 if (wakeup_events) {
5874 struct ring_buffer *rb = handle->rb;
5875 int events = local_inc_return(&rb->events);
5877 if (events >= wakeup_events) {
5878 local_sub(wakeup_events, &rb->events);
5879 local_inc(&rb->wakeup);
5885 void perf_prepare_sample(struct perf_event_header *header,
5886 struct perf_sample_data *data,
5887 struct perf_event *event,
5888 struct pt_regs *regs)
5890 u64 sample_type = event->attr.sample_type;
5892 header->type = PERF_RECORD_SAMPLE;
5893 header->size = sizeof(*header) + event->header_size;
5896 header->misc |= perf_misc_flags(regs);
5898 __perf_event_header__init_id(header, data, event);
5900 if (sample_type & PERF_SAMPLE_IP)
5901 data->ip = perf_instruction_pointer(regs);
5903 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5906 data->callchain = perf_callchain(event, regs);
5908 if (data->callchain)
5909 size += data->callchain->nr;
5911 header->size += size * sizeof(u64);
5914 if (sample_type & PERF_SAMPLE_RAW) {
5915 struct perf_raw_record *raw = data->raw;
5919 struct perf_raw_frag *frag = &raw->frag;
5924 if (perf_raw_frag_last(frag))
5929 size = round_up(sum + sizeof(u32), sizeof(u64));
5930 raw->size = size - sizeof(u32);
5931 frag->pad = raw->size - sum;
5936 header->size += size;
5939 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5940 int size = sizeof(u64); /* nr */
5941 if (data->br_stack) {
5942 size += data->br_stack->nr
5943 * sizeof(struct perf_branch_entry);
5945 header->size += size;
5948 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5949 perf_sample_regs_user(&data->regs_user, regs,
5950 &data->regs_user_copy);
5952 if (sample_type & PERF_SAMPLE_REGS_USER) {
5953 /* regs dump ABI info */
5954 int size = sizeof(u64);
5956 if (data->regs_user.regs) {
5957 u64 mask = event->attr.sample_regs_user;
5958 size += hweight64(mask) * sizeof(u64);
5961 header->size += size;
5964 if (sample_type & PERF_SAMPLE_STACK_USER) {
5966 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5967 * processed as the last one or have additional check added
5968 * in case new sample type is added, because we could eat
5969 * up the rest of the sample size.
5971 u16 stack_size = event->attr.sample_stack_user;
5972 u16 size = sizeof(u64);
5974 stack_size = perf_sample_ustack_size(stack_size, header->size,
5975 data->regs_user.regs);
5978 * If there is something to dump, add space for the dump
5979 * itself and for the field that tells the dynamic size,
5980 * which is how many have been actually dumped.
5983 size += sizeof(u64) + stack_size;
5985 data->stack_user_size = stack_size;
5986 header->size += size;
5989 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5990 /* regs dump ABI info */
5991 int size = sizeof(u64);
5993 perf_sample_regs_intr(&data->regs_intr, regs);
5995 if (data->regs_intr.regs) {
5996 u64 mask = event->attr.sample_regs_intr;
5998 size += hweight64(mask) * sizeof(u64);
6001 header->size += size;
6005 static void __always_inline
6006 __perf_event_output(struct perf_event *event,
6007 struct perf_sample_data *data,
6008 struct pt_regs *regs,
6009 int (*output_begin)(struct perf_output_handle *,
6010 struct perf_event *,
6013 struct perf_output_handle handle;
6014 struct perf_event_header header;
6016 /* protect the callchain buffers */
6019 perf_prepare_sample(&header, data, event, regs);
6021 if (output_begin(&handle, event, header.size))
6024 perf_output_sample(&handle, &header, data, event);
6026 perf_output_end(&handle);
6033 perf_event_output_forward(struct perf_event *event,
6034 struct perf_sample_data *data,
6035 struct pt_regs *regs)
6037 __perf_event_output(event, data, regs, perf_output_begin_forward);
6041 perf_event_output_backward(struct perf_event *event,
6042 struct perf_sample_data *data,
6043 struct pt_regs *regs)
6045 __perf_event_output(event, data, regs, perf_output_begin_backward);
6049 perf_event_output(struct perf_event *event,
6050 struct perf_sample_data *data,
6051 struct pt_regs *regs)
6053 __perf_event_output(event, data, regs, perf_output_begin);
6060 struct perf_read_event {
6061 struct perf_event_header header;
6068 perf_event_read_event(struct perf_event *event,
6069 struct task_struct *task)
6071 struct perf_output_handle handle;
6072 struct perf_sample_data sample;
6073 struct perf_read_event read_event = {
6075 .type = PERF_RECORD_READ,
6077 .size = sizeof(read_event) + event->read_size,
6079 .pid = perf_event_pid(event, task),
6080 .tid = perf_event_tid(event, task),
6084 perf_event_header__init_id(&read_event.header, &sample, event);
6085 ret = perf_output_begin(&handle, event, read_event.header.size);
6089 perf_output_put(&handle, read_event);
6090 perf_output_read(&handle, event);
6091 perf_event__output_id_sample(event, &handle, &sample);
6093 perf_output_end(&handle);
6096 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6099 perf_iterate_ctx(struct perf_event_context *ctx,
6100 perf_iterate_f output,
6101 void *data, bool all)
6103 struct perf_event *event;
6105 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6107 if (event->state < PERF_EVENT_STATE_INACTIVE)
6109 if (!event_filter_match(event))
6113 output(event, data);
6117 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6119 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6120 struct perf_event *event;
6122 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6124 * Skip events that are not fully formed yet; ensure that
6125 * if we observe event->ctx, both event and ctx will be
6126 * complete enough. See perf_install_in_context().
6128 if (!smp_load_acquire(&event->ctx))
6131 if (event->state < PERF_EVENT_STATE_INACTIVE)
6133 if (!event_filter_match(event))
6135 output(event, data);
6140 * Iterate all events that need to receive side-band events.
6142 * For new callers; ensure that account_pmu_sb_event() includes
6143 * your event, otherwise it might not get delivered.
6146 perf_iterate_sb(perf_iterate_f output, void *data,
6147 struct perf_event_context *task_ctx)
6149 struct perf_event_context *ctx;
6156 * If we have task_ctx != NULL we only notify the task context itself.
6157 * The task_ctx is set only for EXIT events before releasing task
6161 perf_iterate_ctx(task_ctx, output, data, false);
6165 perf_iterate_sb_cpu(output, data);
6167 for_each_task_context_nr(ctxn) {
6168 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6170 perf_iterate_ctx(ctx, output, data, false);
6178 * Clear all file-based filters at exec, they'll have to be
6179 * re-instated when/if these objects are mmapped again.
6181 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6183 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6184 struct perf_addr_filter *filter;
6185 unsigned int restart = 0, count = 0;
6186 unsigned long flags;
6188 if (!has_addr_filter(event))
6191 raw_spin_lock_irqsave(&ifh->lock, flags);
6192 list_for_each_entry(filter, &ifh->list, entry) {
6193 if (filter->inode) {
6194 event->addr_filters_offs[count] = 0;
6202 event->addr_filters_gen++;
6203 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6206 perf_event_stop(event, 1);
6209 void perf_event_exec(void)
6211 struct perf_event_context *ctx;
6215 for_each_task_context_nr(ctxn) {
6216 ctx = current->perf_event_ctxp[ctxn];
6220 perf_event_enable_on_exec(ctxn);
6222 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6228 struct remote_output {
6229 struct ring_buffer *rb;
6233 static void __perf_event_output_stop(struct perf_event *event, void *data)
6235 struct perf_event *parent = event->parent;
6236 struct remote_output *ro = data;
6237 struct ring_buffer *rb = ro->rb;
6238 struct stop_event_data sd = {
6242 if (!has_aux(event))
6249 * In case of inheritance, it will be the parent that links to the
6250 * ring-buffer, but it will be the child that's actually using it.
6252 * We are using event::rb to determine if the event should be stopped,
6253 * however this may race with ring_buffer_attach() (through set_output),
6254 * which will make us skip the event that actually needs to be stopped.
6255 * So ring_buffer_attach() has to stop an aux event before re-assigning
6258 if (rcu_dereference(parent->rb) == rb)
6259 ro->err = __perf_event_stop(&sd);
6262 static int __perf_pmu_output_stop(void *info)
6264 struct perf_event *event = info;
6265 struct pmu *pmu = event->pmu;
6266 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6267 struct remote_output ro = {
6272 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6273 if (cpuctx->task_ctx)
6274 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6281 static void perf_pmu_output_stop(struct perf_event *event)
6283 struct perf_event *iter;
6288 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6290 * For per-CPU events, we need to make sure that neither they
6291 * nor their children are running; for cpu==-1 events it's
6292 * sufficient to stop the event itself if it's active, since
6293 * it can't have children.
6297 cpu = READ_ONCE(iter->oncpu);
6302 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6303 if (err == -EAGAIN) {
6312 * task tracking -- fork/exit
6314 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6317 struct perf_task_event {
6318 struct task_struct *task;
6319 struct perf_event_context *task_ctx;
6322 struct perf_event_header header;
6332 static int perf_event_task_match(struct perf_event *event)
6334 return event->attr.comm || event->attr.mmap ||
6335 event->attr.mmap2 || event->attr.mmap_data ||
6339 static void perf_event_task_output(struct perf_event *event,
6342 struct perf_task_event *task_event = data;
6343 struct perf_output_handle handle;
6344 struct perf_sample_data sample;
6345 struct task_struct *task = task_event->task;
6346 int ret, size = task_event->event_id.header.size;
6348 if (!perf_event_task_match(event))
6351 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6353 ret = perf_output_begin(&handle, event,
6354 task_event->event_id.header.size);
6358 task_event->event_id.pid = perf_event_pid(event, task);
6359 task_event->event_id.ppid = perf_event_pid(event, current);
6361 task_event->event_id.tid = perf_event_tid(event, task);
6362 task_event->event_id.ptid = perf_event_tid(event, current);
6364 task_event->event_id.time = perf_event_clock(event);
6366 perf_output_put(&handle, task_event->event_id);
6368 perf_event__output_id_sample(event, &handle, &sample);
6370 perf_output_end(&handle);
6372 task_event->event_id.header.size = size;
6375 static void perf_event_task(struct task_struct *task,
6376 struct perf_event_context *task_ctx,
6379 struct perf_task_event task_event;
6381 if (!atomic_read(&nr_comm_events) &&
6382 !atomic_read(&nr_mmap_events) &&
6383 !atomic_read(&nr_task_events))
6386 task_event = (struct perf_task_event){
6388 .task_ctx = task_ctx,
6391 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6393 .size = sizeof(task_event.event_id),
6403 perf_iterate_sb(perf_event_task_output,
6408 void perf_event_fork(struct task_struct *task)
6410 perf_event_task(task, NULL, 1);
6417 struct perf_comm_event {
6418 struct task_struct *task;
6423 struct perf_event_header header;
6430 static int perf_event_comm_match(struct perf_event *event)
6432 return event->attr.comm;
6435 static void perf_event_comm_output(struct perf_event *event,
6438 struct perf_comm_event *comm_event = data;
6439 struct perf_output_handle handle;
6440 struct perf_sample_data sample;
6441 int size = comm_event->event_id.header.size;
6444 if (!perf_event_comm_match(event))
6447 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6448 ret = perf_output_begin(&handle, event,
6449 comm_event->event_id.header.size);
6454 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6455 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6457 perf_output_put(&handle, comm_event->event_id);
6458 __output_copy(&handle, comm_event->comm,
6459 comm_event->comm_size);
6461 perf_event__output_id_sample(event, &handle, &sample);
6463 perf_output_end(&handle);
6465 comm_event->event_id.header.size = size;
6468 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6470 char comm[TASK_COMM_LEN];
6473 memset(comm, 0, sizeof(comm));
6474 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6475 size = ALIGN(strlen(comm)+1, sizeof(u64));
6477 comm_event->comm = comm;
6478 comm_event->comm_size = size;
6480 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6482 perf_iterate_sb(perf_event_comm_output,
6487 void perf_event_comm(struct task_struct *task, bool exec)
6489 struct perf_comm_event comm_event;
6491 if (!atomic_read(&nr_comm_events))
6494 comm_event = (struct perf_comm_event){
6500 .type = PERF_RECORD_COMM,
6501 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6509 perf_event_comm_event(&comm_event);
6516 struct perf_mmap_event {
6517 struct vm_area_struct *vma;
6519 const char *file_name;
6527 struct perf_event_header header;
6537 static int perf_event_mmap_match(struct perf_event *event,
6540 struct perf_mmap_event *mmap_event = data;
6541 struct vm_area_struct *vma = mmap_event->vma;
6542 int executable = vma->vm_flags & VM_EXEC;
6544 return (!executable && event->attr.mmap_data) ||
6545 (executable && (event->attr.mmap || event->attr.mmap2));
6548 static void perf_event_mmap_output(struct perf_event *event,
6551 struct perf_mmap_event *mmap_event = data;
6552 struct perf_output_handle handle;
6553 struct perf_sample_data sample;
6554 int size = mmap_event->event_id.header.size;
6557 if (!perf_event_mmap_match(event, data))
6560 if (event->attr.mmap2) {
6561 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6562 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6563 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6564 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6565 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6566 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6567 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6570 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6571 ret = perf_output_begin(&handle, event,
6572 mmap_event->event_id.header.size);
6576 mmap_event->event_id.pid = perf_event_pid(event, current);
6577 mmap_event->event_id.tid = perf_event_tid(event, current);
6579 perf_output_put(&handle, mmap_event->event_id);
6581 if (event->attr.mmap2) {
6582 perf_output_put(&handle, mmap_event->maj);
6583 perf_output_put(&handle, mmap_event->min);
6584 perf_output_put(&handle, mmap_event->ino);
6585 perf_output_put(&handle, mmap_event->ino_generation);
6586 perf_output_put(&handle, mmap_event->prot);
6587 perf_output_put(&handle, mmap_event->flags);
6590 __output_copy(&handle, mmap_event->file_name,
6591 mmap_event->file_size);
6593 perf_event__output_id_sample(event, &handle, &sample);
6595 perf_output_end(&handle);
6597 mmap_event->event_id.header.size = size;
6600 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6602 struct vm_area_struct *vma = mmap_event->vma;
6603 struct file *file = vma->vm_file;
6604 int maj = 0, min = 0;
6605 u64 ino = 0, gen = 0;
6606 u32 prot = 0, flags = 0;
6613 struct inode *inode;
6616 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6622 * d_path() works from the end of the rb backwards, so we
6623 * need to add enough zero bytes after the string to handle
6624 * the 64bit alignment we do later.
6626 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6631 inode = file_inode(vma->vm_file);
6632 dev = inode->i_sb->s_dev;
6634 gen = inode->i_generation;
6638 if (vma->vm_flags & VM_READ)
6640 if (vma->vm_flags & VM_WRITE)
6642 if (vma->vm_flags & VM_EXEC)
6645 if (vma->vm_flags & VM_MAYSHARE)
6648 flags = MAP_PRIVATE;
6650 if (vma->vm_flags & VM_DENYWRITE)
6651 flags |= MAP_DENYWRITE;
6652 if (vma->vm_flags & VM_MAYEXEC)
6653 flags |= MAP_EXECUTABLE;
6654 if (vma->vm_flags & VM_LOCKED)
6655 flags |= MAP_LOCKED;
6656 if (vma->vm_flags & VM_HUGETLB)
6657 flags |= MAP_HUGETLB;
6661 if (vma->vm_ops && vma->vm_ops->name) {
6662 name = (char *) vma->vm_ops->name(vma);
6667 name = (char *)arch_vma_name(vma);
6671 if (vma->vm_start <= vma->vm_mm->start_brk &&
6672 vma->vm_end >= vma->vm_mm->brk) {
6676 if (vma->vm_start <= vma->vm_mm->start_stack &&
6677 vma->vm_end >= vma->vm_mm->start_stack) {
6687 strlcpy(tmp, name, sizeof(tmp));
6691 * Since our buffer works in 8 byte units we need to align our string
6692 * size to a multiple of 8. However, we must guarantee the tail end is
6693 * zero'd out to avoid leaking random bits to userspace.
6695 size = strlen(name)+1;
6696 while (!IS_ALIGNED(size, sizeof(u64)))
6697 name[size++] = '\0';
6699 mmap_event->file_name = name;
6700 mmap_event->file_size = size;
6701 mmap_event->maj = maj;
6702 mmap_event->min = min;
6703 mmap_event->ino = ino;
6704 mmap_event->ino_generation = gen;
6705 mmap_event->prot = prot;
6706 mmap_event->flags = flags;
6708 if (!(vma->vm_flags & VM_EXEC))
6709 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6711 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6713 perf_iterate_sb(perf_event_mmap_output,
6721 * Check whether inode and address range match filter criteria.
6723 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6724 struct file *file, unsigned long offset,
6727 if (filter->inode != file_inode(file))
6730 if (filter->offset > offset + size)
6733 if (filter->offset + filter->size < offset)
6739 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6741 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6742 struct vm_area_struct *vma = data;
6743 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6744 struct file *file = vma->vm_file;
6745 struct perf_addr_filter *filter;
6746 unsigned int restart = 0, count = 0;
6748 if (!has_addr_filter(event))
6754 raw_spin_lock_irqsave(&ifh->lock, flags);
6755 list_for_each_entry(filter, &ifh->list, entry) {
6756 if (perf_addr_filter_match(filter, file, off,
6757 vma->vm_end - vma->vm_start)) {
6758 event->addr_filters_offs[count] = vma->vm_start;
6766 event->addr_filters_gen++;
6767 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6770 perf_event_stop(event, 1);
6774 * Adjust all task's events' filters to the new vma
6776 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6778 struct perf_event_context *ctx;
6782 * Data tracing isn't supported yet and as such there is no need
6783 * to keep track of anything that isn't related to executable code:
6785 if (!(vma->vm_flags & VM_EXEC))
6789 for_each_task_context_nr(ctxn) {
6790 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6794 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
6799 void perf_event_mmap(struct vm_area_struct *vma)
6801 struct perf_mmap_event mmap_event;
6803 if (!atomic_read(&nr_mmap_events))
6806 mmap_event = (struct perf_mmap_event){
6812 .type = PERF_RECORD_MMAP,
6813 .misc = PERF_RECORD_MISC_USER,
6818 .start = vma->vm_start,
6819 .len = vma->vm_end - vma->vm_start,
6820 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6822 /* .maj (attr_mmap2 only) */
6823 /* .min (attr_mmap2 only) */
6824 /* .ino (attr_mmap2 only) */
6825 /* .ino_generation (attr_mmap2 only) */
6826 /* .prot (attr_mmap2 only) */
6827 /* .flags (attr_mmap2 only) */
6830 perf_addr_filters_adjust(vma);
6831 perf_event_mmap_event(&mmap_event);
6834 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6835 unsigned long size, u64 flags)
6837 struct perf_output_handle handle;
6838 struct perf_sample_data sample;
6839 struct perf_aux_event {
6840 struct perf_event_header header;
6846 .type = PERF_RECORD_AUX,
6848 .size = sizeof(rec),
6856 perf_event_header__init_id(&rec.header, &sample, event);
6857 ret = perf_output_begin(&handle, event, rec.header.size);
6862 perf_output_put(&handle, rec);
6863 perf_event__output_id_sample(event, &handle, &sample);
6865 perf_output_end(&handle);
6869 * Lost/dropped samples logging
6871 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6873 struct perf_output_handle handle;
6874 struct perf_sample_data sample;
6878 struct perf_event_header header;
6880 } lost_samples_event = {
6882 .type = PERF_RECORD_LOST_SAMPLES,
6884 .size = sizeof(lost_samples_event),
6889 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6891 ret = perf_output_begin(&handle, event,
6892 lost_samples_event.header.size);
6896 perf_output_put(&handle, lost_samples_event);
6897 perf_event__output_id_sample(event, &handle, &sample);
6898 perf_output_end(&handle);
6902 * context_switch tracking
6905 struct perf_switch_event {
6906 struct task_struct *task;
6907 struct task_struct *next_prev;
6910 struct perf_event_header header;
6916 static int perf_event_switch_match(struct perf_event *event)
6918 return event->attr.context_switch;
6921 static void perf_event_switch_output(struct perf_event *event, void *data)
6923 struct perf_switch_event *se = data;
6924 struct perf_output_handle handle;
6925 struct perf_sample_data sample;
6928 if (!perf_event_switch_match(event))
6931 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6932 if (event->ctx->task) {
6933 se->event_id.header.type = PERF_RECORD_SWITCH;
6934 se->event_id.header.size = sizeof(se->event_id.header);
6936 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6937 se->event_id.header.size = sizeof(se->event_id);
6938 se->event_id.next_prev_pid =
6939 perf_event_pid(event, se->next_prev);
6940 se->event_id.next_prev_tid =
6941 perf_event_tid(event, se->next_prev);
6944 perf_event_header__init_id(&se->event_id.header, &sample, event);
6946 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6950 if (event->ctx->task)
6951 perf_output_put(&handle, se->event_id.header);
6953 perf_output_put(&handle, se->event_id);
6955 perf_event__output_id_sample(event, &handle, &sample);
6957 perf_output_end(&handle);
6960 static void perf_event_switch(struct task_struct *task,
6961 struct task_struct *next_prev, bool sched_in)
6963 struct perf_switch_event switch_event;
6965 /* N.B. caller checks nr_switch_events != 0 */
6967 switch_event = (struct perf_switch_event){
6969 .next_prev = next_prev,
6973 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6976 /* .next_prev_pid */
6977 /* .next_prev_tid */
6981 perf_iterate_sb(perf_event_switch_output,
6987 * IRQ throttle logging
6990 static void perf_log_throttle(struct perf_event *event, int enable)
6992 struct perf_output_handle handle;
6993 struct perf_sample_data sample;
6997 struct perf_event_header header;
7001 } throttle_event = {
7003 .type = PERF_RECORD_THROTTLE,
7005 .size = sizeof(throttle_event),
7007 .time = perf_event_clock(event),
7008 .id = primary_event_id(event),
7009 .stream_id = event->id,
7013 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7015 perf_event_header__init_id(&throttle_event.header, &sample, event);
7017 ret = perf_output_begin(&handle, event,
7018 throttle_event.header.size);
7022 perf_output_put(&handle, throttle_event);
7023 perf_event__output_id_sample(event, &handle, &sample);
7024 perf_output_end(&handle);
7027 static void perf_log_itrace_start(struct perf_event *event)
7029 struct perf_output_handle handle;
7030 struct perf_sample_data sample;
7031 struct perf_aux_event {
7032 struct perf_event_header header;
7039 event = event->parent;
7041 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7042 event->hw.itrace_started)
7045 rec.header.type = PERF_RECORD_ITRACE_START;
7046 rec.header.misc = 0;
7047 rec.header.size = sizeof(rec);
7048 rec.pid = perf_event_pid(event, current);
7049 rec.tid = perf_event_tid(event, current);
7051 perf_event_header__init_id(&rec.header, &sample, event);
7052 ret = perf_output_begin(&handle, event, rec.header.size);
7057 perf_output_put(&handle, rec);
7058 perf_event__output_id_sample(event, &handle, &sample);
7060 perf_output_end(&handle);
7064 * Generic event overflow handling, sampling.
7067 static int __perf_event_overflow(struct perf_event *event,
7068 int throttle, struct perf_sample_data *data,
7069 struct pt_regs *regs)
7071 int events = atomic_read(&event->event_limit);
7072 struct hw_perf_event *hwc = &event->hw;
7077 * Non-sampling counters might still use the PMI to fold short
7078 * hardware counters, ignore those.
7080 if (unlikely(!is_sampling_event(event)))
7083 seq = __this_cpu_read(perf_throttled_seq);
7084 if (seq != hwc->interrupts_seq) {
7085 hwc->interrupts_seq = seq;
7086 hwc->interrupts = 1;
7089 if (unlikely(throttle
7090 && hwc->interrupts >= max_samples_per_tick)) {
7091 __this_cpu_inc(perf_throttled_count);
7092 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7093 hwc->interrupts = MAX_INTERRUPTS;
7094 perf_log_throttle(event, 0);
7099 if (event->attr.freq) {
7100 u64 now = perf_clock();
7101 s64 delta = now - hwc->freq_time_stamp;
7103 hwc->freq_time_stamp = now;
7105 if (delta > 0 && delta < 2*TICK_NSEC)
7106 perf_adjust_period(event, delta, hwc->last_period, true);
7110 * XXX event_limit might not quite work as expected on inherited
7114 event->pending_kill = POLL_IN;
7115 if (events && atomic_dec_and_test(&event->event_limit)) {
7117 event->pending_kill = POLL_HUP;
7119 perf_event_disable_inatomic(event);
7122 READ_ONCE(event->overflow_handler)(event, data, regs);
7124 if (*perf_event_fasync(event) && event->pending_kill) {
7125 event->pending_wakeup = 1;
7126 irq_work_queue(&event->pending);
7132 int perf_event_overflow(struct perf_event *event,
7133 struct perf_sample_data *data,
7134 struct pt_regs *regs)
7136 return __perf_event_overflow(event, 1, data, regs);
7140 * Generic software event infrastructure
7143 struct swevent_htable {
7144 struct swevent_hlist *swevent_hlist;
7145 struct mutex hlist_mutex;
7148 /* Recursion avoidance in each contexts */
7149 int recursion[PERF_NR_CONTEXTS];
7152 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7155 * We directly increment event->count and keep a second value in
7156 * event->hw.period_left to count intervals. This period event
7157 * is kept in the range [-sample_period, 0] so that we can use the
7161 u64 perf_swevent_set_period(struct perf_event *event)
7163 struct hw_perf_event *hwc = &event->hw;
7164 u64 period = hwc->last_period;
7168 hwc->last_period = hwc->sample_period;
7171 old = val = local64_read(&hwc->period_left);
7175 nr = div64_u64(period + val, period);
7176 offset = nr * period;
7178 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7184 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7185 struct perf_sample_data *data,
7186 struct pt_regs *regs)
7188 struct hw_perf_event *hwc = &event->hw;
7192 overflow = perf_swevent_set_period(event);
7194 if (hwc->interrupts == MAX_INTERRUPTS)
7197 for (; overflow; overflow--) {
7198 if (__perf_event_overflow(event, throttle,
7201 * We inhibit the overflow from happening when
7202 * hwc->interrupts == MAX_INTERRUPTS.
7210 static void perf_swevent_event(struct perf_event *event, u64 nr,
7211 struct perf_sample_data *data,
7212 struct pt_regs *regs)
7214 struct hw_perf_event *hwc = &event->hw;
7216 local64_add(nr, &event->count);
7221 if (!is_sampling_event(event))
7224 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7226 return perf_swevent_overflow(event, 1, data, regs);
7228 data->period = event->hw.last_period;
7230 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7231 return perf_swevent_overflow(event, 1, data, regs);
7233 if (local64_add_negative(nr, &hwc->period_left))
7236 perf_swevent_overflow(event, 0, data, regs);
7239 static int perf_exclude_event(struct perf_event *event,
7240 struct pt_regs *regs)
7242 if (event->hw.state & PERF_HES_STOPPED)
7246 if (event->attr.exclude_user && user_mode(regs))
7249 if (event->attr.exclude_kernel && !user_mode(regs))
7256 static int perf_swevent_match(struct perf_event *event,
7257 enum perf_type_id type,
7259 struct perf_sample_data *data,
7260 struct pt_regs *regs)
7262 if (event->attr.type != type)
7265 if (event->attr.config != event_id)
7268 if (perf_exclude_event(event, regs))
7274 static inline u64 swevent_hash(u64 type, u32 event_id)
7276 u64 val = event_id | (type << 32);
7278 return hash_64(val, SWEVENT_HLIST_BITS);
7281 static inline struct hlist_head *
7282 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7284 u64 hash = swevent_hash(type, event_id);
7286 return &hlist->heads[hash];
7289 /* For the read side: events when they trigger */
7290 static inline struct hlist_head *
7291 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7293 struct swevent_hlist *hlist;
7295 hlist = rcu_dereference(swhash->swevent_hlist);
7299 return __find_swevent_head(hlist, type, event_id);
7302 /* For the event head insertion and removal in the hlist */
7303 static inline struct hlist_head *
7304 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7306 struct swevent_hlist *hlist;
7307 u32 event_id = event->attr.config;
7308 u64 type = event->attr.type;
7311 * Event scheduling is always serialized against hlist allocation
7312 * and release. Which makes the protected version suitable here.
7313 * The context lock guarantees that.
7315 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7316 lockdep_is_held(&event->ctx->lock));
7320 return __find_swevent_head(hlist, type, event_id);
7323 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7325 struct perf_sample_data *data,
7326 struct pt_regs *regs)
7328 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7329 struct perf_event *event;
7330 struct hlist_head *head;
7333 head = find_swevent_head_rcu(swhash, type, event_id);
7337 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7338 if (perf_swevent_match(event, type, event_id, data, regs))
7339 perf_swevent_event(event, nr, data, regs);
7345 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7347 int perf_swevent_get_recursion_context(void)
7349 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7351 return get_recursion_context(swhash->recursion);
7353 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7355 void perf_swevent_put_recursion_context(int rctx)
7357 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7359 put_recursion_context(swhash->recursion, rctx);
7362 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7364 struct perf_sample_data data;
7366 if (WARN_ON_ONCE(!regs))
7369 perf_sample_data_init(&data, addr, 0);
7370 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7373 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7377 preempt_disable_notrace();
7378 rctx = perf_swevent_get_recursion_context();
7379 if (unlikely(rctx < 0))
7382 ___perf_sw_event(event_id, nr, regs, addr);
7384 perf_swevent_put_recursion_context(rctx);
7386 preempt_enable_notrace();
7389 static void perf_swevent_read(struct perf_event *event)
7393 static int perf_swevent_add(struct perf_event *event, int flags)
7395 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7396 struct hw_perf_event *hwc = &event->hw;
7397 struct hlist_head *head;
7399 if (is_sampling_event(event)) {
7400 hwc->last_period = hwc->sample_period;
7401 perf_swevent_set_period(event);
7404 hwc->state = !(flags & PERF_EF_START);
7406 head = find_swevent_head(swhash, event);
7407 if (WARN_ON_ONCE(!head))
7410 hlist_add_head_rcu(&event->hlist_entry, head);
7411 perf_event_update_userpage(event);
7416 static void perf_swevent_del(struct perf_event *event, int flags)
7418 hlist_del_rcu(&event->hlist_entry);
7421 static void perf_swevent_start(struct perf_event *event, int flags)
7423 event->hw.state = 0;
7426 static void perf_swevent_stop(struct perf_event *event, int flags)
7428 event->hw.state = PERF_HES_STOPPED;
7431 /* Deref the hlist from the update side */
7432 static inline struct swevent_hlist *
7433 swevent_hlist_deref(struct swevent_htable *swhash)
7435 return rcu_dereference_protected(swhash->swevent_hlist,
7436 lockdep_is_held(&swhash->hlist_mutex));
7439 static void swevent_hlist_release(struct swevent_htable *swhash)
7441 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7446 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7447 kfree_rcu(hlist, rcu_head);
7450 static void swevent_hlist_put_cpu(int cpu)
7452 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7454 mutex_lock(&swhash->hlist_mutex);
7456 if (!--swhash->hlist_refcount)
7457 swevent_hlist_release(swhash);
7459 mutex_unlock(&swhash->hlist_mutex);
7462 static void swevent_hlist_put(void)
7466 for_each_possible_cpu(cpu)
7467 swevent_hlist_put_cpu(cpu);
7470 static int swevent_hlist_get_cpu(int cpu)
7472 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7475 mutex_lock(&swhash->hlist_mutex);
7476 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
7477 struct swevent_hlist *hlist;
7479 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7484 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7486 swhash->hlist_refcount++;
7488 mutex_unlock(&swhash->hlist_mutex);
7493 static int swevent_hlist_get(void)
7495 int err, cpu, failed_cpu;
7498 for_each_possible_cpu(cpu) {
7499 err = swevent_hlist_get_cpu(cpu);
7509 for_each_possible_cpu(cpu) {
7510 if (cpu == failed_cpu)
7512 swevent_hlist_put_cpu(cpu);
7519 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7521 static void sw_perf_event_destroy(struct perf_event *event)
7523 u64 event_id = event->attr.config;
7525 WARN_ON(event->parent);
7527 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7528 swevent_hlist_put();
7531 static int perf_swevent_init(struct perf_event *event)
7533 u64 event_id = event->attr.config;
7535 if (event->attr.type != PERF_TYPE_SOFTWARE)
7539 * no branch sampling for software events
7541 if (has_branch_stack(event))
7545 case PERF_COUNT_SW_CPU_CLOCK:
7546 case PERF_COUNT_SW_TASK_CLOCK:
7553 if (event_id >= PERF_COUNT_SW_MAX)
7556 if (!event->parent) {
7559 err = swevent_hlist_get();
7563 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7564 event->destroy = sw_perf_event_destroy;
7570 static struct pmu perf_swevent = {
7571 .task_ctx_nr = perf_sw_context,
7573 .capabilities = PERF_PMU_CAP_NO_NMI,
7575 .event_init = perf_swevent_init,
7576 .add = perf_swevent_add,
7577 .del = perf_swevent_del,
7578 .start = perf_swevent_start,
7579 .stop = perf_swevent_stop,
7580 .read = perf_swevent_read,
7583 #ifdef CONFIG_EVENT_TRACING
7585 static int perf_tp_filter_match(struct perf_event *event,
7586 struct perf_sample_data *data)
7588 void *record = data->raw->frag.data;
7590 /* only top level events have filters set */
7592 event = event->parent;
7594 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7599 static int perf_tp_event_match(struct perf_event *event,
7600 struct perf_sample_data *data,
7601 struct pt_regs *regs)
7603 if (event->hw.state & PERF_HES_STOPPED)
7606 * All tracepoints are from kernel-space.
7608 if (event->attr.exclude_kernel)
7611 if (!perf_tp_filter_match(event, data))
7617 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7618 struct trace_event_call *call, u64 count,
7619 struct pt_regs *regs, struct hlist_head *head,
7620 struct task_struct *task)
7622 struct bpf_prog *prog = call->prog;
7625 *(struct pt_regs **)raw_data = regs;
7626 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7627 perf_swevent_put_recursion_context(rctx);
7631 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7634 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7636 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7637 struct pt_regs *regs, struct hlist_head *head, int rctx,
7638 struct task_struct *task)
7640 struct perf_sample_data data;
7641 struct perf_event *event;
7643 struct perf_raw_record raw = {
7650 perf_sample_data_init(&data, 0, 0);
7653 perf_trace_buf_update(record, event_type);
7655 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7656 if (perf_tp_event_match(event, &data, regs))
7657 perf_swevent_event(event, count, &data, regs);
7661 * If we got specified a target task, also iterate its context and
7662 * deliver this event there too.
7664 if (task && task != current) {
7665 struct perf_event_context *ctx;
7666 struct trace_entry *entry = record;
7669 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7673 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7674 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7676 if (event->attr.config != entry->type)
7678 if (perf_tp_event_match(event, &data, regs))
7679 perf_swevent_event(event, count, &data, regs);
7685 perf_swevent_put_recursion_context(rctx);
7687 EXPORT_SYMBOL_GPL(perf_tp_event);
7689 static void tp_perf_event_destroy(struct perf_event *event)
7691 perf_trace_destroy(event);
7694 static int perf_tp_event_init(struct perf_event *event)
7698 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7702 * no branch sampling for tracepoint events
7704 if (has_branch_stack(event))
7707 err = perf_trace_init(event);
7711 event->destroy = tp_perf_event_destroy;
7716 static struct pmu perf_tracepoint = {
7717 .task_ctx_nr = perf_sw_context,
7719 .event_init = perf_tp_event_init,
7720 .add = perf_trace_add,
7721 .del = perf_trace_del,
7722 .start = perf_swevent_start,
7723 .stop = perf_swevent_stop,
7724 .read = perf_swevent_read,
7727 static inline void perf_tp_register(void)
7729 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7732 static void perf_event_free_filter(struct perf_event *event)
7734 ftrace_profile_free_filter(event);
7737 #ifdef CONFIG_BPF_SYSCALL
7738 static void bpf_overflow_handler(struct perf_event *event,
7739 struct perf_sample_data *data,
7740 struct pt_regs *regs)
7742 struct bpf_perf_event_data_kern ctx = {
7749 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7752 ret = BPF_PROG_RUN(event->prog, &ctx);
7755 __this_cpu_dec(bpf_prog_active);
7760 event->orig_overflow_handler(event, data, regs);
7763 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7765 struct bpf_prog *prog;
7767 if (event->overflow_handler_context)
7768 /* hw breakpoint or kernel counter */
7774 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
7776 return PTR_ERR(prog);
7779 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
7780 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
7784 static void perf_event_free_bpf_handler(struct perf_event *event)
7786 struct bpf_prog *prog = event->prog;
7791 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
7796 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7800 static void perf_event_free_bpf_handler(struct perf_event *event)
7805 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7807 bool is_kprobe, is_tracepoint;
7808 struct bpf_prog *prog;
7810 if (event->attr.type == PERF_TYPE_HARDWARE ||
7811 event->attr.type == PERF_TYPE_SOFTWARE)
7812 return perf_event_set_bpf_handler(event, prog_fd);
7814 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7817 if (event->tp_event->prog)
7820 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
7821 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
7822 if (!is_kprobe && !is_tracepoint)
7823 /* bpf programs can only be attached to u/kprobe or tracepoint */
7826 prog = bpf_prog_get(prog_fd);
7828 return PTR_ERR(prog);
7830 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
7831 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
7832 /* valid fd, but invalid bpf program type */
7837 if (is_tracepoint) {
7838 int off = trace_event_get_offsets(event->tp_event);
7840 if (prog->aux->max_ctx_offset > off) {
7845 event->tp_event->prog = prog;
7850 static void perf_event_free_bpf_prog(struct perf_event *event)
7852 struct bpf_prog *prog;
7854 perf_event_free_bpf_handler(event);
7856 if (!event->tp_event)
7859 prog = event->tp_event->prog;
7861 event->tp_event->prog = NULL;
7868 static inline void perf_tp_register(void)
7872 static void perf_event_free_filter(struct perf_event *event)
7876 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7881 static void perf_event_free_bpf_prog(struct perf_event *event)
7884 #endif /* CONFIG_EVENT_TRACING */
7886 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7887 void perf_bp_event(struct perf_event *bp, void *data)
7889 struct perf_sample_data sample;
7890 struct pt_regs *regs = data;
7892 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7894 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7895 perf_swevent_event(bp, 1, &sample, regs);
7900 * Allocate a new address filter
7902 static struct perf_addr_filter *
7903 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
7905 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
7906 struct perf_addr_filter *filter;
7908 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
7912 INIT_LIST_HEAD(&filter->entry);
7913 list_add_tail(&filter->entry, filters);
7918 static void free_filters_list(struct list_head *filters)
7920 struct perf_addr_filter *filter, *iter;
7922 list_for_each_entry_safe(filter, iter, filters, entry) {
7924 iput(filter->inode);
7925 list_del(&filter->entry);
7931 * Free existing address filters and optionally install new ones
7933 static void perf_addr_filters_splice(struct perf_event *event,
7934 struct list_head *head)
7936 unsigned long flags;
7939 if (!has_addr_filter(event))
7942 /* don't bother with children, they don't have their own filters */
7946 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
7948 list_splice_init(&event->addr_filters.list, &list);
7950 list_splice(head, &event->addr_filters.list);
7952 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
7954 free_filters_list(&list);
7958 * Scan through mm's vmas and see if one of them matches the
7959 * @filter; if so, adjust filter's address range.
7960 * Called with mm::mmap_sem down for reading.
7962 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
7963 struct mm_struct *mm)
7965 struct vm_area_struct *vma;
7967 for (vma = mm->mmap; vma; vma = vma->vm_next) {
7968 struct file *file = vma->vm_file;
7969 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7970 unsigned long vma_size = vma->vm_end - vma->vm_start;
7975 if (!perf_addr_filter_match(filter, file, off, vma_size))
7978 return vma->vm_start;
7985 * Update event's address range filters based on the
7986 * task's existing mappings, if any.
7988 static void perf_event_addr_filters_apply(struct perf_event *event)
7990 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7991 struct task_struct *task = READ_ONCE(event->ctx->task);
7992 struct perf_addr_filter *filter;
7993 struct mm_struct *mm = NULL;
7994 unsigned int count = 0;
7995 unsigned long flags;
7998 * We may observe TASK_TOMBSTONE, which means that the event tear-down
7999 * will stop on the parent's child_mutex that our caller is also holding
8001 if (task == TASK_TOMBSTONE)
8004 mm = get_task_mm(event->ctx->task);
8008 down_read(&mm->mmap_sem);
8010 raw_spin_lock_irqsave(&ifh->lock, flags);
8011 list_for_each_entry(filter, &ifh->list, entry) {
8012 event->addr_filters_offs[count] = 0;
8015 * Adjust base offset if the filter is associated to a binary
8016 * that needs to be mapped:
8019 event->addr_filters_offs[count] =
8020 perf_addr_filter_apply(filter, mm);
8025 event->addr_filters_gen++;
8026 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8028 up_read(&mm->mmap_sem);
8033 perf_event_stop(event, 1);
8037 * Address range filtering: limiting the data to certain
8038 * instruction address ranges. Filters are ioctl()ed to us from
8039 * userspace as ascii strings.
8041 * Filter string format:
8044 * where ACTION is one of the
8045 * * "filter": limit the trace to this region
8046 * * "start": start tracing from this address
8047 * * "stop": stop tracing at this address/region;
8049 * * for kernel addresses: <start address>[/<size>]
8050 * * for object files: <start address>[/<size>]@</path/to/object/file>
8052 * if <size> is not specified, the range is treated as a single address.
8066 IF_STATE_ACTION = 0,
8071 static const match_table_t if_tokens = {
8072 { IF_ACT_FILTER, "filter" },
8073 { IF_ACT_START, "start" },
8074 { IF_ACT_STOP, "stop" },
8075 { IF_SRC_FILE, "%u/%u@%s" },
8076 { IF_SRC_KERNEL, "%u/%u" },
8077 { IF_SRC_FILEADDR, "%u@%s" },
8078 { IF_SRC_KERNELADDR, "%u" },
8079 { IF_ACT_NONE, NULL },
8083 * Address filter string parser
8086 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8087 struct list_head *filters)
8089 struct perf_addr_filter *filter = NULL;
8090 char *start, *orig, *filename = NULL;
8092 substring_t args[MAX_OPT_ARGS];
8093 int state = IF_STATE_ACTION, token;
8094 unsigned int kernel = 0;
8097 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8101 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8107 /* filter definition begins */
8108 if (state == IF_STATE_ACTION) {
8109 filter = perf_addr_filter_new(event, filters);
8114 token = match_token(start, if_tokens, args);
8121 if (state != IF_STATE_ACTION)
8124 state = IF_STATE_SOURCE;
8127 case IF_SRC_KERNELADDR:
8131 case IF_SRC_FILEADDR:
8133 if (state != IF_STATE_SOURCE)
8136 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8140 ret = kstrtoul(args[0].from, 0, &filter->offset);
8144 if (filter->range) {
8146 ret = kstrtoul(args[1].from, 0, &filter->size);
8151 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8152 int fpos = filter->range ? 2 : 1;
8154 filename = match_strdup(&args[fpos]);
8161 state = IF_STATE_END;
8169 * Filter definition is fully parsed, validate and install it.
8170 * Make sure that it doesn't contradict itself or the event's
8173 if (state == IF_STATE_END) {
8174 if (kernel && event->attr.exclude_kernel)
8181 /* look up the path and grab its inode */
8182 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8184 goto fail_free_name;
8186 filter->inode = igrab(d_inode(path.dentry));
8192 if (!filter->inode ||
8193 !S_ISREG(filter->inode->i_mode))
8194 /* free_filters_list() will iput() */
8198 /* ready to consume more filters */
8199 state = IF_STATE_ACTION;
8204 if (state != IF_STATE_ACTION)
8214 free_filters_list(filters);
8221 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8227 * Since this is called in perf_ioctl() path, we're already holding
8230 lockdep_assert_held(&event->ctx->mutex);
8232 if (WARN_ON_ONCE(event->parent))
8236 * For now, we only support filtering in per-task events; doing so
8237 * for CPU-wide events requires additional context switching trickery,
8238 * since same object code will be mapped at different virtual
8239 * addresses in different processes.
8241 if (!event->ctx->task)
8244 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8248 ret = event->pmu->addr_filters_validate(&filters);
8250 free_filters_list(&filters);
8254 /* remove existing filters, if any */
8255 perf_addr_filters_splice(event, &filters);
8257 /* install new filters */
8258 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8263 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8268 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8269 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8270 !has_addr_filter(event))
8273 filter_str = strndup_user(arg, PAGE_SIZE);
8274 if (IS_ERR(filter_str))
8275 return PTR_ERR(filter_str);
8277 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8278 event->attr.type == PERF_TYPE_TRACEPOINT)
8279 ret = ftrace_profile_set_filter(event, event->attr.config,
8281 else if (has_addr_filter(event))
8282 ret = perf_event_set_addr_filter(event, filter_str);
8289 * hrtimer based swevent callback
8292 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8294 enum hrtimer_restart ret = HRTIMER_RESTART;
8295 struct perf_sample_data data;
8296 struct pt_regs *regs;
8297 struct perf_event *event;
8300 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8302 if (event->state != PERF_EVENT_STATE_ACTIVE)
8303 return HRTIMER_NORESTART;
8305 event->pmu->read(event);
8307 perf_sample_data_init(&data, 0, event->hw.last_period);
8308 regs = get_irq_regs();
8310 if (regs && !perf_exclude_event(event, regs)) {
8311 if (!(event->attr.exclude_idle && is_idle_task(current)))
8312 if (__perf_event_overflow(event, 1, &data, regs))
8313 ret = HRTIMER_NORESTART;
8316 period = max_t(u64, 10000, event->hw.sample_period);
8317 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8322 static void perf_swevent_start_hrtimer(struct perf_event *event)
8324 struct hw_perf_event *hwc = &event->hw;
8327 if (!is_sampling_event(event))
8330 period = local64_read(&hwc->period_left);
8335 local64_set(&hwc->period_left, 0);
8337 period = max_t(u64, 10000, hwc->sample_period);
8339 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8340 HRTIMER_MODE_REL_PINNED);
8343 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8345 struct hw_perf_event *hwc = &event->hw;
8347 if (is_sampling_event(event)) {
8348 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8349 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8351 hrtimer_cancel(&hwc->hrtimer);
8355 static void perf_swevent_init_hrtimer(struct perf_event *event)
8357 struct hw_perf_event *hwc = &event->hw;
8359 if (!is_sampling_event(event))
8362 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8363 hwc->hrtimer.function = perf_swevent_hrtimer;
8366 * Since hrtimers have a fixed rate, we can do a static freq->period
8367 * mapping and avoid the whole period adjust feedback stuff.
8369 if (event->attr.freq) {
8370 long freq = event->attr.sample_freq;
8372 event->attr.sample_period = NSEC_PER_SEC / freq;
8373 hwc->sample_period = event->attr.sample_period;
8374 local64_set(&hwc->period_left, hwc->sample_period);
8375 hwc->last_period = hwc->sample_period;
8376 event->attr.freq = 0;
8381 * Software event: cpu wall time clock
8384 static void cpu_clock_event_update(struct perf_event *event)
8389 now = local_clock();
8390 prev = local64_xchg(&event->hw.prev_count, now);
8391 local64_add(now - prev, &event->count);
8394 static void cpu_clock_event_start(struct perf_event *event, int flags)
8396 local64_set(&event->hw.prev_count, local_clock());
8397 perf_swevent_start_hrtimer(event);
8400 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8402 perf_swevent_cancel_hrtimer(event);
8403 cpu_clock_event_update(event);
8406 static int cpu_clock_event_add(struct perf_event *event, int flags)
8408 if (flags & PERF_EF_START)
8409 cpu_clock_event_start(event, flags);
8410 perf_event_update_userpage(event);
8415 static void cpu_clock_event_del(struct perf_event *event, int flags)
8417 cpu_clock_event_stop(event, flags);
8420 static void cpu_clock_event_read(struct perf_event *event)
8422 cpu_clock_event_update(event);
8425 static int cpu_clock_event_init(struct perf_event *event)
8427 if (event->attr.type != PERF_TYPE_SOFTWARE)
8430 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8434 * no branch sampling for software events
8436 if (has_branch_stack(event))
8439 perf_swevent_init_hrtimer(event);
8444 static struct pmu perf_cpu_clock = {
8445 .task_ctx_nr = perf_sw_context,
8447 .capabilities = PERF_PMU_CAP_NO_NMI,
8449 .event_init = cpu_clock_event_init,
8450 .add = cpu_clock_event_add,
8451 .del = cpu_clock_event_del,
8452 .start = cpu_clock_event_start,
8453 .stop = cpu_clock_event_stop,
8454 .read = cpu_clock_event_read,
8458 * Software event: task time clock
8461 static void task_clock_event_update(struct perf_event *event, u64 now)
8466 prev = local64_xchg(&event->hw.prev_count, now);
8468 local64_add(delta, &event->count);
8471 static void task_clock_event_start(struct perf_event *event, int flags)
8473 local64_set(&event->hw.prev_count, event->ctx->time);
8474 perf_swevent_start_hrtimer(event);
8477 static void task_clock_event_stop(struct perf_event *event, int flags)
8479 perf_swevent_cancel_hrtimer(event);
8480 task_clock_event_update(event, event->ctx->time);
8483 static int task_clock_event_add(struct perf_event *event, int flags)
8485 if (flags & PERF_EF_START)
8486 task_clock_event_start(event, flags);
8487 perf_event_update_userpage(event);
8492 static void task_clock_event_del(struct perf_event *event, int flags)
8494 task_clock_event_stop(event, PERF_EF_UPDATE);
8497 static void task_clock_event_read(struct perf_event *event)
8499 u64 now = perf_clock();
8500 u64 delta = now - event->ctx->timestamp;
8501 u64 time = event->ctx->time + delta;
8503 task_clock_event_update(event, time);
8506 static int task_clock_event_init(struct perf_event *event)
8508 if (event->attr.type != PERF_TYPE_SOFTWARE)
8511 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8515 * no branch sampling for software events
8517 if (has_branch_stack(event))
8520 perf_swevent_init_hrtimer(event);
8525 static struct pmu perf_task_clock = {
8526 .task_ctx_nr = perf_sw_context,
8528 .capabilities = PERF_PMU_CAP_NO_NMI,
8530 .event_init = task_clock_event_init,
8531 .add = task_clock_event_add,
8532 .del = task_clock_event_del,
8533 .start = task_clock_event_start,
8534 .stop = task_clock_event_stop,
8535 .read = task_clock_event_read,
8538 static void perf_pmu_nop_void(struct pmu *pmu)
8542 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8546 static int perf_pmu_nop_int(struct pmu *pmu)
8551 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8553 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8555 __this_cpu_write(nop_txn_flags, flags);
8557 if (flags & ~PERF_PMU_TXN_ADD)
8560 perf_pmu_disable(pmu);
8563 static int perf_pmu_commit_txn(struct pmu *pmu)
8565 unsigned int flags = __this_cpu_read(nop_txn_flags);
8567 __this_cpu_write(nop_txn_flags, 0);
8569 if (flags & ~PERF_PMU_TXN_ADD)
8572 perf_pmu_enable(pmu);
8576 static void perf_pmu_cancel_txn(struct pmu *pmu)
8578 unsigned int flags = __this_cpu_read(nop_txn_flags);
8580 __this_cpu_write(nop_txn_flags, 0);
8582 if (flags & ~PERF_PMU_TXN_ADD)
8585 perf_pmu_enable(pmu);
8588 static int perf_event_idx_default(struct perf_event *event)
8594 * Ensures all contexts with the same task_ctx_nr have the same
8595 * pmu_cpu_context too.
8597 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8604 list_for_each_entry(pmu, &pmus, entry) {
8605 if (pmu->task_ctx_nr == ctxn)
8606 return pmu->pmu_cpu_context;
8612 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
8616 for_each_possible_cpu(cpu) {
8617 struct perf_cpu_context *cpuctx;
8619 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8621 if (cpuctx->unique_pmu == old_pmu)
8622 cpuctx->unique_pmu = pmu;
8626 static void free_pmu_context(struct pmu *pmu)
8630 mutex_lock(&pmus_lock);
8632 * Like a real lame refcount.
8634 list_for_each_entry(i, &pmus, entry) {
8635 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
8636 update_pmu_context(i, pmu);
8641 free_percpu(pmu->pmu_cpu_context);
8643 mutex_unlock(&pmus_lock);
8647 * Let userspace know that this PMU supports address range filtering:
8649 static ssize_t nr_addr_filters_show(struct device *dev,
8650 struct device_attribute *attr,
8653 struct pmu *pmu = dev_get_drvdata(dev);
8655 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8657 DEVICE_ATTR_RO(nr_addr_filters);
8659 static struct idr pmu_idr;
8662 type_show(struct device *dev, struct device_attribute *attr, char *page)
8664 struct pmu *pmu = dev_get_drvdata(dev);
8666 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8668 static DEVICE_ATTR_RO(type);
8671 perf_event_mux_interval_ms_show(struct device *dev,
8672 struct device_attribute *attr,
8675 struct pmu *pmu = dev_get_drvdata(dev);
8677 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8680 static DEFINE_MUTEX(mux_interval_mutex);
8683 perf_event_mux_interval_ms_store(struct device *dev,
8684 struct device_attribute *attr,
8685 const char *buf, size_t count)
8687 struct pmu *pmu = dev_get_drvdata(dev);
8688 int timer, cpu, ret;
8690 ret = kstrtoint(buf, 0, &timer);
8697 /* same value, noting to do */
8698 if (timer == pmu->hrtimer_interval_ms)
8701 mutex_lock(&mux_interval_mutex);
8702 pmu->hrtimer_interval_ms = timer;
8704 /* update all cpuctx for this PMU */
8706 for_each_online_cpu(cpu) {
8707 struct perf_cpu_context *cpuctx;
8708 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8709 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8711 cpu_function_call(cpu,
8712 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8715 mutex_unlock(&mux_interval_mutex);
8719 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8721 static struct attribute *pmu_dev_attrs[] = {
8722 &dev_attr_type.attr,
8723 &dev_attr_perf_event_mux_interval_ms.attr,
8726 ATTRIBUTE_GROUPS(pmu_dev);
8728 static int pmu_bus_running;
8729 static struct bus_type pmu_bus = {
8730 .name = "event_source",
8731 .dev_groups = pmu_dev_groups,
8734 static void pmu_dev_release(struct device *dev)
8739 static int pmu_dev_alloc(struct pmu *pmu)
8743 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8747 pmu->dev->groups = pmu->attr_groups;
8748 device_initialize(pmu->dev);
8749 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8753 dev_set_drvdata(pmu->dev, pmu);
8754 pmu->dev->bus = &pmu_bus;
8755 pmu->dev->release = pmu_dev_release;
8756 ret = device_add(pmu->dev);
8760 /* For PMUs with address filters, throw in an extra attribute: */
8761 if (pmu->nr_addr_filters)
8762 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8771 device_del(pmu->dev);
8774 put_device(pmu->dev);
8778 static struct lock_class_key cpuctx_mutex;
8779 static struct lock_class_key cpuctx_lock;
8781 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8785 mutex_lock(&pmus_lock);
8787 pmu->pmu_disable_count = alloc_percpu(int);
8788 if (!pmu->pmu_disable_count)
8797 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
8805 if (pmu_bus_running) {
8806 ret = pmu_dev_alloc(pmu);
8812 if (pmu->task_ctx_nr == perf_hw_context) {
8813 static int hw_context_taken = 0;
8816 * Other than systems with heterogeneous CPUs, it never makes
8817 * sense for two PMUs to share perf_hw_context. PMUs which are
8818 * uncore must use perf_invalid_context.
8820 if (WARN_ON_ONCE(hw_context_taken &&
8821 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
8822 pmu->task_ctx_nr = perf_invalid_context;
8824 hw_context_taken = 1;
8827 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
8828 if (pmu->pmu_cpu_context)
8829 goto got_cpu_context;
8832 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
8833 if (!pmu->pmu_cpu_context)
8836 for_each_possible_cpu(cpu) {
8837 struct perf_cpu_context *cpuctx;
8839 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8840 __perf_event_init_context(&cpuctx->ctx);
8841 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
8842 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
8843 cpuctx->ctx.pmu = pmu;
8845 __perf_mux_hrtimer_init(cpuctx, cpu);
8847 cpuctx->unique_pmu = pmu;
8851 if (!pmu->start_txn) {
8852 if (pmu->pmu_enable) {
8854 * If we have pmu_enable/pmu_disable calls, install
8855 * transaction stubs that use that to try and batch
8856 * hardware accesses.
8858 pmu->start_txn = perf_pmu_start_txn;
8859 pmu->commit_txn = perf_pmu_commit_txn;
8860 pmu->cancel_txn = perf_pmu_cancel_txn;
8862 pmu->start_txn = perf_pmu_nop_txn;
8863 pmu->commit_txn = perf_pmu_nop_int;
8864 pmu->cancel_txn = perf_pmu_nop_void;
8868 if (!pmu->pmu_enable) {
8869 pmu->pmu_enable = perf_pmu_nop_void;
8870 pmu->pmu_disable = perf_pmu_nop_void;
8873 if (!pmu->event_idx)
8874 pmu->event_idx = perf_event_idx_default;
8876 list_add_rcu(&pmu->entry, &pmus);
8877 atomic_set(&pmu->exclusive_cnt, 0);
8880 mutex_unlock(&pmus_lock);
8885 device_del(pmu->dev);
8886 put_device(pmu->dev);
8889 if (pmu->type >= PERF_TYPE_MAX)
8890 idr_remove(&pmu_idr, pmu->type);
8893 free_percpu(pmu->pmu_disable_count);
8896 EXPORT_SYMBOL_GPL(perf_pmu_register);
8898 void perf_pmu_unregister(struct pmu *pmu)
8902 mutex_lock(&pmus_lock);
8903 remove_device = pmu_bus_running;
8904 list_del_rcu(&pmu->entry);
8905 mutex_unlock(&pmus_lock);
8908 * We dereference the pmu list under both SRCU and regular RCU, so
8909 * synchronize against both of those.
8911 synchronize_srcu(&pmus_srcu);
8914 free_percpu(pmu->pmu_disable_count);
8915 if (pmu->type >= PERF_TYPE_MAX)
8916 idr_remove(&pmu_idr, pmu->type);
8917 if (remove_device) {
8918 if (pmu->nr_addr_filters)
8919 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
8920 device_del(pmu->dev);
8921 put_device(pmu->dev);
8923 free_pmu_context(pmu);
8925 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
8927 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
8929 struct perf_event_context *ctx = NULL;
8932 if (!try_module_get(pmu->module))
8935 if (event->group_leader != event) {
8937 * This ctx->mutex can nest when we're called through
8938 * inheritance. See the perf_event_ctx_lock_nested() comment.
8940 ctx = perf_event_ctx_lock_nested(event->group_leader,
8941 SINGLE_DEPTH_NESTING);
8946 ret = pmu->event_init(event);
8949 perf_event_ctx_unlock(event->group_leader, ctx);
8952 module_put(pmu->module);
8957 static struct pmu *perf_init_event(struct perf_event *event)
8959 struct pmu *pmu = NULL;
8963 idx = srcu_read_lock(&pmus_srcu);
8966 pmu = idr_find(&pmu_idr, event->attr.type);
8969 ret = perf_try_init_event(pmu, event);
8975 list_for_each_entry_rcu(pmu, &pmus, entry) {
8976 ret = perf_try_init_event(pmu, event);
8980 if (ret != -ENOENT) {
8985 pmu = ERR_PTR(-ENOENT);
8987 srcu_read_unlock(&pmus_srcu, idx);
8992 static void attach_sb_event(struct perf_event *event)
8994 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
8996 raw_spin_lock(&pel->lock);
8997 list_add_rcu(&event->sb_list, &pel->list);
8998 raw_spin_unlock(&pel->lock);
9002 * We keep a list of all !task (and therefore per-cpu) events
9003 * that need to receive side-band records.
9005 * This avoids having to scan all the various PMU per-cpu contexts
9008 static void account_pmu_sb_event(struct perf_event *event)
9010 if (is_sb_event(event))
9011 attach_sb_event(event);
9014 static void account_event_cpu(struct perf_event *event, int cpu)
9019 if (is_cgroup_event(event))
9020 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9023 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9024 static void account_freq_event_nohz(void)
9026 #ifdef CONFIG_NO_HZ_FULL
9027 /* Lock so we don't race with concurrent unaccount */
9028 spin_lock(&nr_freq_lock);
9029 if (atomic_inc_return(&nr_freq_events) == 1)
9030 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9031 spin_unlock(&nr_freq_lock);
9035 static void account_freq_event(void)
9037 if (tick_nohz_full_enabled())
9038 account_freq_event_nohz();
9040 atomic_inc(&nr_freq_events);
9044 static void account_event(struct perf_event *event)
9051 if (event->attach_state & PERF_ATTACH_TASK)
9053 if (event->attr.mmap || event->attr.mmap_data)
9054 atomic_inc(&nr_mmap_events);
9055 if (event->attr.comm)
9056 atomic_inc(&nr_comm_events);
9057 if (event->attr.task)
9058 atomic_inc(&nr_task_events);
9059 if (event->attr.freq)
9060 account_freq_event();
9061 if (event->attr.context_switch) {
9062 atomic_inc(&nr_switch_events);
9065 if (has_branch_stack(event))
9067 if (is_cgroup_event(event))
9071 if (atomic_inc_not_zero(&perf_sched_count))
9074 mutex_lock(&perf_sched_mutex);
9075 if (!atomic_read(&perf_sched_count)) {
9076 static_branch_enable(&perf_sched_events);
9078 * Guarantee that all CPUs observe they key change and
9079 * call the perf scheduling hooks before proceeding to
9080 * install events that need them.
9082 synchronize_sched();
9085 * Now that we have waited for the sync_sched(), allow further
9086 * increments to by-pass the mutex.
9088 atomic_inc(&perf_sched_count);
9089 mutex_unlock(&perf_sched_mutex);
9093 account_event_cpu(event, event->cpu);
9095 account_pmu_sb_event(event);
9099 * Allocate and initialize a event structure
9101 static struct perf_event *
9102 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9103 struct task_struct *task,
9104 struct perf_event *group_leader,
9105 struct perf_event *parent_event,
9106 perf_overflow_handler_t overflow_handler,
9107 void *context, int cgroup_fd)
9110 struct perf_event *event;
9111 struct hw_perf_event *hwc;
9114 if ((unsigned)cpu >= nr_cpu_ids) {
9115 if (!task || cpu != -1)
9116 return ERR_PTR(-EINVAL);
9119 event = kzalloc(sizeof(*event), GFP_KERNEL);
9121 return ERR_PTR(-ENOMEM);
9124 * Single events are their own group leaders, with an
9125 * empty sibling list:
9128 group_leader = event;
9130 mutex_init(&event->child_mutex);
9131 INIT_LIST_HEAD(&event->child_list);
9133 INIT_LIST_HEAD(&event->group_entry);
9134 INIT_LIST_HEAD(&event->event_entry);
9135 INIT_LIST_HEAD(&event->sibling_list);
9136 INIT_LIST_HEAD(&event->rb_entry);
9137 INIT_LIST_HEAD(&event->active_entry);
9138 INIT_LIST_HEAD(&event->addr_filters.list);
9139 INIT_HLIST_NODE(&event->hlist_entry);
9142 init_waitqueue_head(&event->waitq);
9143 init_irq_work(&event->pending, perf_pending_event);
9145 mutex_init(&event->mmap_mutex);
9146 raw_spin_lock_init(&event->addr_filters.lock);
9148 atomic_long_set(&event->refcount, 1);
9150 event->attr = *attr;
9151 event->group_leader = group_leader;
9155 event->parent = parent_event;
9157 event->ns = get_pid_ns(task_active_pid_ns(current));
9158 event->id = atomic64_inc_return(&perf_event_id);
9160 event->state = PERF_EVENT_STATE_INACTIVE;
9163 event->attach_state = PERF_ATTACH_TASK;
9165 * XXX pmu::event_init needs to know what task to account to
9166 * and we cannot use the ctx information because we need the
9167 * pmu before we get a ctx.
9169 event->hw.target = task;
9172 event->clock = &local_clock;
9174 event->clock = parent_event->clock;
9176 if (!overflow_handler && parent_event) {
9177 overflow_handler = parent_event->overflow_handler;
9178 context = parent_event->overflow_handler_context;
9179 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9180 if (overflow_handler == bpf_overflow_handler) {
9181 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9184 err = PTR_ERR(prog);
9188 event->orig_overflow_handler =
9189 parent_event->orig_overflow_handler;
9194 if (overflow_handler) {
9195 event->overflow_handler = overflow_handler;
9196 event->overflow_handler_context = context;
9197 } else if (is_write_backward(event)){
9198 event->overflow_handler = perf_event_output_backward;
9199 event->overflow_handler_context = NULL;
9201 event->overflow_handler = perf_event_output_forward;
9202 event->overflow_handler_context = NULL;
9205 perf_event__state_init(event);
9210 hwc->sample_period = attr->sample_period;
9211 if (attr->freq && attr->sample_freq)
9212 hwc->sample_period = 1;
9213 hwc->last_period = hwc->sample_period;
9215 local64_set(&hwc->period_left, hwc->sample_period);
9218 * we currently do not support PERF_FORMAT_GROUP on inherited events
9220 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
9223 if (!has_branch_stack(event))
9224 event->attr.branch_sample_type = 0;
9226 if (cgroup_fd != -1) {
9227 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9232 pmu = perf_init_event(event);
9235 else if (IS_ERR(pmu)) {
9240 err = exclusive_event_init(event);
9244 if (has_addr_filter(event)) {
9245 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9246 sizeof(unsigned long),
9248 if (!event->addr_filters_offs)
9251 /* force hw sync on the address filters */
9252 event->addr_filters_gen = 1;
9255 if (!event->parent) {
9256 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9257 err = get_callchain_buffers(attr->sample_max_stack);
9259 goto err_addr_filters;
9263 /* symmetric to unaccount_event() in _free_event() */
9264 account_event(event);
9269 kfree(event->addr_filters_offs);
9272 exclusive_event_destroy(event);
9276 event->destroy(event);
9277 module_put(pmu->module);
9279 if (is_cgroup_event(event))
9280 perf_detach_cgroup(event);
9282 put_pid_ns(event->ns);
9285 return ERR_PTR(err);
9288 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9289 struct perf_event_attr *attr)
9294 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9298 * zero the full structure, so that a short copy will be nice.
9300 memset(attr, 0, sizeof(*attr));
9302 ret = get_user(size, &uattr->size);
9306 if (size > PAGE_SIZE) /* silly large */
9309 if (!size) /* abi compat */
9310 size = PERF_ATTR_SIZE_VER0;
9312 if (size < PERF_ATTR_SIZE_VER0)
9316 * If we're handed a bigger struct than we know of,
9317 * ensure all the unknown bits are 0 - i.e. new
9318 * user-space does not rely on any kernel feature
9319 * extensions we dont know about yet.
9321 if (size > sizeof(*attr)) {
9322 unsigned char __user *addr;
9323 unsigned char __user *end;
9326 addr = (void __user *)uattr + sizeof(*attr);
9327 end = (void __user *)uattr + size;
9329 for (; addr < end; addr++) {
9330 ret = get_user(val, addr);
9336 size = sizeof(*attr);
9339 ret = copy_from_user(attr, uattr, size);
9343 if (attr->__reserved_1)
9346 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9349 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9352 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9353 u64 mask = attr->branch_sample_type;
9355 /* only using defined bits */
9356 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9359 /* at least one branch bit must be set */
9360 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9363 /* propagate priv level, when not set for branch */
9364 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9366 /* exclude_kernel checked on syscall entry */
9367 if (!attr->exclude_kernel)
9368 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9370 if (!attr->exclude_user)
9371 mask |= PERF_SAMPLE_BRANCH_USER;
9373 if (!attr->exclude_hv)
9374 mask |= PERF_SAMPLE_BRANCH_HV;
9376 * adjust user setting (for HW filter setup)
9378 attr->branch_sample_type = mask;
9380 /* privileged levels capture (kernel, hv): check permissions */
9381 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9382 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9386 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9387 ret = perf_reg_validate(attr->sample_regs_user);
9392 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9393 if (!arch_perf_have_user_stack_dump())
9397 * We have __u32 type for the size, but so far
9398 * we can only use __u16 as maximum due to the
9399 * __u16 sample size limit.
9401 if (attr->sample_stack_user >= USHRT_MAX)
9403 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9407 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9408 ret = perf_reg_validate(attr->sample_regs_intr);
9413 put_user(sizeof(*attr), &uattr->size);
9419 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9421 struct ring_buffer *rb = NULL;
9427 /* don't allow circular references */
9428 if (event == output_event)
9432 * Don't allow cross-cpu buffers
9434 if (output_event->cpu != event->cpu)
9438 * If its not a per-cpu rb, it must be the same task.
9440 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9444 * Mixing clocks in the same buffer is trouble you don't need.
9446 if (output_event->clock != event->clock)
9450 * Either writing ring buffer from beginning or from end.
9451 * Mixing is not allowed.
9453 if (is_write_backward(output_event) != is_write_backward(event))
9457 * If both events generate aux data, they must be on the same PMU
9459 if (has_aux(event) && has_aux(output_event) &&
9460 event->pmu != output_event->pmu)
9464 mutex_lock(&event->mmap_mutex);
9465 /* Can't redirect output if we've got an active mmap() */
9466 if (atomic_read(&event->mmap_count))
9470 /* get the rb we want to redirect to */
9471 rb = ring_buffer_get(output_event);
9476 ring_buffer_attach(event, rb);
9480 mutex_unlock(&event->mmap_mutex);
9486 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9492 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9495 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9497 bool nmi_safe = false;
9500 case CLOCK_MONOTONIC:
9501 event->clock = &ktime_get_mono_fast_ns;
9505 case CLOCK_MONOTONIC_RAW:
9506 event->clock = &ktime_get_raw_fast_ns;
9510 case CLOCK_REALTIME:
9511 event->clock = &ktime_get_real_ns;
9514 case CLOCK_BOOTTIME:
9515 event->clock = &ktime_get_boot_ns;
9519 event->clock = &ktime_get_tai_ns;
9526 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9533 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9535 * @attr_uptr: event_id type attributes for monitoring/sampling
9538 * @group_fd: group leader event fd
9540 SYSCALL_DEFINE5(perf_event_open,
9541 struct perf_event_attr __user *, attr_uptr,
9542 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9544 struct perf_event *group_leader = NULL, *output_event = NULL;
9545 struct perf_event *event, *sibling;
9546 struct perf_event_attr attr;
9547 struct perf_event_context *ctx, *uninitialized_var(gctx);
9548 struct file *event_file = NULL;
9549 struct fd group = {NULL, 0};
9550 struct task_struct *task = NULL;
9555 int f_flags = O_RDWR;
9558 /* for future expandability... */
9559 if (flags & ~PERF_FLAG_ALL)
9562 err = perf_copy_attr(attr_uptr, &attr);
9566 if (!attr.exclude_kernel) {
9567 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9572 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9575 if (attr.sample_period & (1ULL << 63))
9579 if (!attr.sample_max_stack)
9580 attr.sample_max_stack = sysctl_perf_event_max_stack;
9583 * In cgroup mode, the pid argument is used to pass the fd
9584 * opened to the cgroup directory in cgroupfs. The cpu argument
9585 * designates the cpu on which to monitor threads from that
9588 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9591 if (flags & PERF_FLAG_FD_CLOEXEC)
9592 f_flags |= O_CLOEXEC;
9594 event_fd = get_unused_fd_flags(f_flags);
9598 if (group_fd != -1) {
9599 err = perf_fget_light(group_fd, &group);
9602 group_leader = group.file->private_data;
9603 if (flags & PERF_FLAG_FD_OUTPUT)
9604 output_event = group_leader;
9605 if (flags & PERF_FLAG_FD_NO_GROUP)
9606 group_leader = NULL;
9609 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9610 task = find_lively_task_by_vpid(pid);
9612 err = PTR_ERR(task);
9617 if (task && group_leader &&
9618 group_leader->attr.inherit != attr.inherit) {
9626 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9631 * Reuse ptrace permission checks for now.
9633 * We must hold cred_guard_mutex across this and any potential
9634 * perf_install_in_context() call for this new event to
9635 * serialize against exec() altering our credentials (and the
9636 * perf_event_exit_task() that could imply).
9639 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9643 if (flags & PERF_FLAG_PID_CGROUP)
9646 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9647 NULL, NULL, cgroup_fd);
9648 if (IS_ERR(event)) {
9649 err = PTR_ERR(event);
9653 if (is_sampling_event(event)) {
9654 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9661 * Special case software events and allow them to be part of
9662 * any hardware group.
9666 if (attr.use_clockid) {
9667 err = perf_event_set_clock(event, attr.clockid);
9672 if (pmu->task_ctx_nr == perf_sw_context)
9673 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9676 (is_software_event(event) != is_software_event(group_leader))) {
9677 if (is_software_event(event)) {
9679 * If event and group_leader are not both a software
9680 * event, and event is, then group leader is not.
9682 * Allow the addition of software events to !software
9683 * groups, this is safe because software events never
9686 pmu = group_leader->pmu;
9687 } else if (is_software_event(group_leader) &&
9688 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9690 * In case the group is a pure software group, and we
9691 * try to add a hardware event, move the whole group to
9692 * the hardware context.
9699 * Get the target context (task or percpu):
9701 ctx = find_get_context(pmu, task, event);
9707 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9713 * Look up the group leader (we will attach this event to it):
9719 * Do not allow a recursive hierarchy (this new sibling
9720 * becoming part of another group-sibling):
9722 if (group_leader->group_leader != group_leader)
9725 /* All events in a group should have the same clock */
9726 if (group_leader->clock != event->clock)
9730 * Do not allow to attach to a group in a different
9731 * task or CPU context:
9735 * Make sure we're both on the same task, or both
9738 if (group_leader->ctx->task != ctx->task)
9742 * Make sure we're both events for the same CPU;
9743 * grouping events for different CPUs is broken; since
9744 * you can never concurrently schedule them anyhow.
9746 if (group_leader->cpu != event->cpu)
9749 if (group_leader->ctx != ctx)
9754 * Only a group leader can be exclusive or pinned
9756 if (attr.exclusive || attr.pinned)
9761 err = perf_event_set_output(event, output_event);
9766 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
9768 if (IS_ERR(event_file)) {
9769 err = PTR_ERR(event_file);
9775 gctx = group_leader->ctx;
9776 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9777 if (gctx->task == TASK_TOMBSTONE) {
9782 mutex_lock(&ctx->mutex);
9785 if (ctx->task == TASK_TOMBSTONE) {
9790 if (!perf_event_validate_size(event)) {
9796 * Must be under the same ctx::mutex as perf_install_in_context(),
9797 * because we need to serialize with concurrent event creation.
9799 if (!exclusive_event_installable(event, ctx)) {
9800 /* exclusive and group stuff are assumed mutually exclusive */
9801 WARN_ON_ONCE(move_group);
9807 WARN_ON_ONCE(ctx->parent_ctx);
9810 * This is the point on no return; we cannot fail hereafter. This is
9811 * where we start modifying current state.
9816 * See perf_event_ctx_lock() for comments on the details
9817 * of swizzling perf_event::ctx.
9819 perf_remove_from_context(group_leader, 0);
9821 list_for_each_entry(sibling, &group_leader->sibling_list,
9823 perf_remove_from_context(sibling, 0);
9828 * Wait for everybody to stop referencing the events through
9829 * the old lists, before installing it on new lists.
9834 * Install the group siblings before the group leader.
9836 * Because a group leader will try and install the entire group
9837 * (through the sibling list, which is still in-tact), we can
9838 * end up with siblings installed in the wrong context.
9840 * By installing siblings first we NO-OP because they're not
9841 * reachable through the group lists.
9843 list_for_each_entry(sibling, &group_leader->sibling_list,
9845 perf_event__state_init(sibling);
9846 perf_install_in_context(ctx, sibling, sibling->cpu);
9851 * Removing from the context ends up with disabled
9852 * event. What we want here is event in the initial
9853 * startup state, ready to be add into new context.
9855 perf_event__state_init(group_leader);
9856 perf_install_in_context(ctx, group_leader, group_leader->cpu);
9860 * Now that all events are installed in @ctx, nothing
9861 * references @gctx anymore, so drop the last reference we have
9868 * Precalculate sample_data sizes; do while holding ctx::mutex such
9869 * that we're serialized against further additions and before
9870 * perf_install_in_context() which is the point the event is active and
9871 * can use these values.
9873 perf_event__header_size(event);
9874 perf_event__id_header_size(event);
9876 event->owner = current;
9878 perf_install_in_context(ctx, event, event->cpu);
9879 perf_unpin_context(ctx);
9882 mutex_unlock(&gctx->mutex);
9883 mutex_unlock(&ctx->mutex);
9886 mutex_unlock(&task->signal->cred_guard_mutex);
9887 put_task_struct(task);
9892 mutex_lock(¤t->perf_event_mutex);
9893 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
9894 mutex_unlock(¤t->perf_event_mutex);
9897 * Drop the reference on the group_event after placing the
9898 * new event on the sibling_list. This ensures destruction
9899 * of the group leader will find the pointer to itself in
9900 * perf_group_detach().
9903 fd_install(event_fd, event_file);
9908 mutex_unlock(&gctx->mutex);
9909 mutex_unlock(&ctx->mutex);
9913 perf_unpin_context(ctx);
9917 * If event_file is set, the fput() above will have called ->release()
9918 * and that will take care of freeing the event.
9924 mutex_unlock(&task->signal->cred_guard_mutex);
9929 put_task_struct(task);
9933 put_unused_fd(event_fd);
9938 * perf_event_create_kernel_counter
9940 * @attr: attributes of the counter to create
9941 * @cpu: cpu in which the counter is bound
9942 * @task: task to profile (NULL for percpu)
9945 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
9946 struct task_struct *task,
9947 perf_overflow_handler_t overflow_handler,
9950 struct perf_event_context *ctx;
9951 struct perf_event *event;
9955 * Get the target context (task or percpu):
9958 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
9959 overflow_handler, context, -1);
9960 if (IS_ERR(event)) {
9961 err = PTR_ERR(event);
9965 /* Mark owner so we could distinguish it from user events. */
9966 event->owner = TASK_TOMBSTONE;
9968 ctx = find_get_context(event->pmu, task, event);
9974 WARN_ON_ONCE(ctx->parent_ctx);
9975 mutex_lock(&ctx->mutex);
9976 if (ctx->task == TASK_TOMBSTONE) {
9981 if (!exclusive_event_installable(event, ctx)) {
9986 perf_install_in_context(ctx, event, cpu);
9987 perf_unpin_context(ctx);
9988 mutex_unlock(&ctx->mutex);
9993 mutex_unlock(&ctx->mutex);
9994 perf_unpin_context(ctx);
9999 return ERR_PTR(err);
10001 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10003 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10005 struct perf_event_context *src_ctx;
10006 struct perf_event_context *dst_ctx;
10007 struct perf_event *event, *tmp;
10010 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10011 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10014 * See perf_event_ctx_lock() for comments on the details
10015 * of swizzling perf_event::ctx.
10017 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10018 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10020 perf_remove_from_context(event, 0);
10021 unaccount_event_cpu(event, src_cpu);
10023 list_add(&event->migrate_entry, &events);
10027 * Wait for the events to quiesce before re-instating them.
10032 * Re-instate events in 2 passes.
10034 * Skip over group leaders and only install siblings on this first
10035 * pass, siblings will not get enabled without a leader, however a
10036 * leader will enable its siblings, even if those are still on the old
10039 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10040 if (event->group_leader == event)
10043 list_del(&event->migrate_entry);
10044 if (event->state >= PERF_EVENT_STATE_OFF)
10045 event->state = PERF_EVENT_STATE_INACTIVE;
10046 account_event_cpu(event, dst_cpu);
10047 perf_install_in_context(dst_ctx, event, dst_cpu);
10052 * Once all the siblings are setup properly, install the group leaders
10055 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10056 list_del(&event->migrate_entry);
10057 if (event->state >= PERF_EVENT_STATE_OFF)
10058 event->state = PERF_EVENT_STATE_INACTIVE;
10059 account_event_cpu(event, dst_cpu);
10060 perf_install_in_context(dst_ctx, event, dst_cpu);
10063 mutex_unlock(&dst_ctx->mutex);
10064 mutex_unlock(&src_ctx->mutex);
10066 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10068 static void sync_child_event(struct perf_event *child_event,
10069 struct task_struct *child)
10071 struct perf_event *parent_event = child_event->parent;
10074 if (child_event->attr.inherit_stat)
10075 perf_event_read_event(child_event, child);
10077 child_val = perf_event_count(child_event);
10080 * Add back the child's count to the parent's count:
10082 atomic64_add(child_val, &parent_event->child_count);
10083 atomic64_add(child_event->total_time_enabled,
10084 &parent_event->child_total_time_enabled);
10085 atomic64_add(child_event->total_time_running,
10086 &parent_event->child_total_time_running);
10090 perf_event_exit_event(struct perf_event *child_event,
10091 struct perf_event_context *child_ctx,
10092 struct task_struct *child)
10094 struct perf_event *parent_event = child_event->parent;
10097 * Do not destroy the 'original' grouping; because of the context
10098 * switch optimization the original events could've ended up in a
10099 * random child task.
10101 * If we were to destroy the original group, all group related
10102 * operations would cease to function properly after this random
10105 * Do destroy all inherited groups, we don't care about those
10106 * and being thorough is better.
10108 raw_spin_lock_irq(&child_ctx->lock);
10109 WARN_ON_ONCE(child_ctx->is_active);
10112 perf_group_detach(child_event);
10113 list_del_event(child_event, child_ctx);
10114 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10115 raw_spin_unlock_irq(&child_ctx->lock);
10118 * Parent events are governed by their filedesc, retain them.
10120 if (!parent_event) {
10121 perf_event_wakeup(child_event);
10125 * Child events can be cleaned up.
10128 sync_child_event(child_event, child);
10131 * Remove this event from the parent's list
10133 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10134 mutex_lock(&parent_event->child_mutex);
10135 list_del_init(&child_event->child_list);
10136 mutex_unlock(&parent_event->child_mutex);
10139 * Kick perf_poll() for is_event_hup().
10141 perf_event_wakeup(parent_event);
10142 free_event(child_event);
10143 put_event(parent_event);
10146 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10148 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10149 struct perf_event *child_event, *next;
10151 WARN_ON_ONCE(child != current);
10153 child_ctx = perf_pin_task_context(child, ctxn);
10158 * In order to reduce the amount of tricky in ctx tear-down, we hold
10159 * ctx::mutex over the entire thing. This serializes against almost
10160 * everything that wants to access the ctx.
10162 * The exception is sys_perf_event_open() /
10163 * perf_event_create_kernel_count() which does find_get_context()
10164 * without ctx::mutex (it cannot because of the move_group double mutex
10165 * lock thing). See the comments in perf_install_in_context().
10167 mutex_lock(&child_ctx->mutex);
10170 * In a single ctx::lock section, de-schedule the events and detach the
10171 * context from the task such that we cannot ever get it scheduled back
10174 raw_spin_lock_irq(&child_ctx->lock);
10175 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx);
10178 * Now that the context is inactive, destroy the task <-> ctx relation
10179 * and mark the context dead.
10181 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10182 put_ctx(child_ctx); /* cannot be last */
10183 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10184 put_task_struct(current); /* cannot be last */
10186 clone_ctx = unclone_ctx(child_ctx);
10187 raw_spin_unlock_irq(&child_ctx->lock);
10190 put_ctx(clone_ctx);
10193 * Report the task dead after unscheduling the events so that we
10194 * won't get any samples after PERF_RECORD_EXIT. We can however still
10195 * get a few PERF_RECORD_READ events.
10197 perf_event_task(child, child_ctx, 0);
10199 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10200 perf_event_exit_event(child_event, child_ctx, child);
10202 mutex_unlock(&child_ctx->mutex);
10204 put_ctx(child_ctx);
10208 * When a child task exits, feed back event values to parent events.
10210 * Can be called with cred_guard_mutex held when called from
10211 * install_exec_creds().
10213 void perf_event_exit_task(struct task_struct *child)
10215 struct perf_event *event, *tmp;
10218 mutex_lock(&child->perf_event_mutex);
10219 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10221 list_del_init(&event->owner_entry);
10224 * Ensure the list deletion is visible before we clear
10225 * the owner, closes a race against perf_release() where
10226 * we need to serialize on the owner->perf_event_mutex.
10228 smp_store_release(&event->owner, NULL);
10230 mutex_unlock(&child->perf_event_mutex);
10232 for_each_task_context_nr(ctxn)
10233 perf_event_exit_task_context(child, ctxn);
10236 * The perf_event_exit_task_context calls perf_event_task
10237 * with child's task_ctx, which generates EXIT events for
10238 * child contexts and sets child->perf_event_ctxp[] to NULL.
10239 * At this point we need to send EXIT events to cpu contexts.
10241 perf_event_task(child, NULL, 0);
10244 static void perf_free_event(struct perf_event *event,
10245 struct perf_event_context *ctx)
10247 struct perf_event *parent = event->parent;
10249 if (WARN_ON_ONCE(!parent))
10252 mutex_lock(&parent->child_mutex);
10253 list_del_init(&event->child_list);
10254 mutex_unlock(&parent->child_mutex);
10258 raw_spin_lock_irq(&ctx->lock);
10259 perf_group_detach(event);
10260 list_del_event(event, ctx);
10261 raw_spin_unlock_irq(&ctx->lock);
10266 * Free an unexposed, unused context as created by inheritance by
10267 * perf_event_init_task below, used by fork() in case of fail.
10269 * Not all locks are strictly required, but take them anyway to be nice and
10270 * help out with the lockdep assertions.
10272 void perf_event_free_task(struct task_struct *task)
10274 struct perf_event_context *ctx;
10275 struct perf_event *event, *tmp;
10278 for_each_task_context_nr(ctxn) {
10279 ctx = task->perf_event_ctxp[ctxn];
10283 mutex_lock(&ctx->mutex);
10285 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
10287 perf_free_event(event, ctx);
10289 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
10291 perf_free_event(event, ctx);
10293 if (!list_empty(&ctx->pinned_groups) ||
10294 !list_empty(&ctx->flexible_groups))
10297 mutex_unlock(&ctx->mutex);
10303 void perf_event_delayed_put(struct task_struct *task)
10307 for_each_task_context_nr(ctxn)
10308 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10311 struct file *perf_event_get(unsigned int fd)
10315 file = fget_raw(fd);
10317 return ERR_PTR(-EBADF);
10319 if (file->f_op != &perf_fops) {
10321 return ERR_PTR(-EBADF);
10327 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10330 return ERR_PTR(-EINVAL);
10332 return &event->attr;
10336 * inherit a event from parent task to child task:
10338 static struct perf_event *
10339 inherit_event(struct perf_event *parent_event,
10340 struct task_struct *parent,
10341 struct perf_event_context *parent_ctx,
10342 struct task_struct *child,
10343 struct perf_event *group_leader,
10344 struct perf_event_context *child_ctx)
10346 enum perf_event_active_state parent_state = parent_event->state;
10347 struct perf_event *child_event;
10348 unsigned long flags;
10351 * Instead of creating recursive hierarchies of events,
10352 * we link inherited events back to the original parent,
10353 * which has a filp for sure, which we use as the reference
10356 if (parent_event->parent)
10357 parent_event = parent_event->parent;
10359 child_event = perf_event_alloc(&parent_event->attr,
10362 group_leader, parent_event,
10364 if (IS_ERR(child_event))
10365 return child_event;
10368 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10369 * must be under the same lock in order to serialize against
10370 * perf_event_release_kernel(), such that either we must observe
10371 * is_orphaned_event() or they will observe us on the child_list.
10373 mutex_lock(&parent_event->child_mutex);
10374 if (is_orphaned_event(parent_event) ||
10375 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10376 mutex_unlock(&parent_event->child_mutex);
10377 free_event(child_event);
10381 get_ctx(child_ctx);
10384 * Make the child state follow the state of the parent event,
10385 * not its attr.disabled bit. We hold the parent's mutex,
10386 * so we won't race with perf_event_{en, dis}able_family.
10388 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10389 child_event->state = PERF_EVENT_STATE_INACTIVE;
10391 child_event->state = PERF_EVENT_STATE_OFF;
10393 if (parent_event->attr.freq) {
10394 u64 sample_period = parent_event->hw.sample_period;
10395 struct hw_perf_event *hwc = &child_event->hw;
10397 hwc->sample_period = sample_period;
10398 hwc->last_period = sample_period;
10400 local64_set(&hwc->period_left, sample_period);
10403 child_event->ctx = child_ctx;
10404 child_event->overflow_handler = parent_event->overflow_handler;
10405 child_event->overflow_handler_context
10406 = parent_event->overflow_handler_context;
10409 * Precalculate sample_data sizes
10411 perf_event__header_size(child_event);
10412 perf_event__id_header_size(child_event);
10415 * Link it up in the child's context:
10417 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10418 add_event_to_ctx(child_event, child_ctx);
10419 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10422 * Link this into the parent event's child list
10424 list_add_tail(&child_event->child_list, &parent_event->child_list);
10425 mutex_unlock(&parent_event->child_mutex);
10427 return child_event;
10430 static int inherit_group(struct perf_event *parent_event,
10431 struct task_struct *parent,
10432 struct perf_event_context *parent_ctx,
10433 struct task_struct *child,
10434 struct perf_event_context *child_ctx)
10436 struct perf_event *leader;
10437 struct perf_event *sub;
10438 struct perf_event *child_ctr;
10440 leader = inherit_event(parent_event, parent, parent_ctx,
10441 child, NULL, child_ctx);
10442 if (IS_ERR(leader))
10443 return PTR_ERR(leader);
10444 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10445 child_ctr = inherit_event(sub, parent, parent_ctx,
10446 child, leader, child_ctx);
10447 if (IS_ERR(child_ctr))
10448 return PTR_ERR(child_ctr);
10454 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10455 struct perf_event_context *parent_ctx,
10456 struct task_struct *child, int ctxn,
10457 int *inherited_all)
10460 struct perf_event_context *child_ctx;
10462 if (!event->attr.inherit) {
10463 *inherited_all = 0;
10467 child_ctx = child->perf_event_ctxp[ctxn];
10470 * This is executed from the parent task context, so
10471 * inherit events that have been marked for cloning.
10472 * First allocate and initialize a context for the
10476 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10480 child->perf_event_ctxp[ctxn] = child_ctx;
10483 ret = inherit_group(event, parent, parent_ctx,
10487 *inherited_all = 0;
10493 * Initialize the perf_event context in task_struct
10495 static int perf_event_init_context(struct task_struct *child, int ctxn)
10497 struct perf_event_context *child_ctx, *parent_ctx;
10498 struct perf_event_context *cloned_ctx;
10499 struct perf_event *event;
10500 struct task_struct *parent = current;
10501 int inherited_all = 1;
10502 unsigned long flags;
10505 if (likely(!parent->perf_event_ctxp[ctxn]))
10509 * If the parent's context is a clone, pin it so it won't get
10510 * swapped under us.
10512 parent_ctx = perf_pin_task_context(parent, ctxn);
10517 * No need to check if parent_ctx != NULL here; since we saw
10518 * it non-NULL earlier, the only reason for it to become NULL
10519 * is if we exit, and since we're currently in the middle of
10520 * a fork we can't be exiting at the same time.
10524 * Lock the parent list. No need to lock the child - not PID
10525 * hashed yet and not running, so nobody can access it.
10527 mutex_lock(&parent_ctx->mutex);
10530 * We dont have to disable NMIs - we are only looking at
10531 * the list, not manipulating it:
10533 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10534 ret = inherit_task_group(event, parent, parent_ctx,
10535 child, ctxn, &inherited_all);
10541 * We can't hold ctx->lock when iterating the ->flexible_group list due
10542 * to allocations, but we need to prevent rotation because
10543 * rotate_ctx() will change the list from interrupt context.
10545 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10546 parent_ctx->rotate_disable = 1;
10547 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10549 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10550 ret = inherit_task_group(event, parent, parent_ctx,
10551 child, ctxn, &inherited_all);
10556 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10557 parent_ctx->rotate_disable = 0;
10559 child_ctx = child->perf_event_ctxp[ctxn];
10561 if (child_ctx && inherited_all) {
10563 * Mark the child context as a clone of the parent
10564 * context, or of whatever the parent is a clone of.
10566 * Note that if the parent is a clone, the holding of
10567 * parent_ctx->lock avoids it from being uncloned.
10569 cloned_ctx = parent_ctx->parent_ctx;
10571 child_ctx->parent_ctx = cloned_ctx;
10572 child_ctx->parent_gen = parent_ctx->parent_gen;
10574 child_ctx->parent_ctx = parent_ctx;
10575 child_ctx->parent_gen = parent_ctx->generation;
10577 get_ctx(child_ctx->parent_ctx);
10580 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10581 mutex_unlock(&parent_ctx->mutex);
10583 perf_unpin_context(parent_ctx);
10584 put_ctx(parent_ctx);
10590 * Initialize the perf_event context in task_struct
10592 int perf_event_init_task(struct task_struct *child)
10596 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10597 mutex_init(&child->perf_event_mutex);
10598 INIT_LIST_HEAD(&child->perf_event_list);
10600 for_each_task_context_nr(ctxn) {
10601 ret = perf_event_init_context(child, ctxn);
10603 perf_event_free_task(child);
10611 static void __init perf_event_init_all_cpus(void)
10613 struct swevent_htable *swhash;
10616 for_each_possible_cpu(cpu) {
10617 swhash = &per_cpu(swevent_htable, cpu);
10618 mutex_init(&swhash->hlist_mutex);
10619 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10621 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10622 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10624 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10628 int perf_event_init_cpu(unsigned int cpu)
10630 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10632 mutex_lock(&swhash->hlist_mutex);
10633 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10634 struct swevent_hlist *hlist;
10636 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10638 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10640 mutex_unlock(&swhash->hlist_mutex);
10644 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10645 static void __perf_event_exit_context(void *__info)
10647 struct perf_event_context *ctx = __info;
10648 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10649 struct perf_event *event;
10651 raw_spin_lock(&ctx->lock);
10652 list_for_each_entry(event, &ctx->event_list, event_entry)
10653 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10654 raw_spin_unlock(&ctx->lock);
10657 static void perf_event_exit_cpu_context(int cpu)
10659 struct perf_event_context *ctx;
10663 idx = srcu_read_lock(&pmus_srcu);
10664 list_for_each_entry_rcu(pmu, &pmus, entry) {
10665 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
10667 mutex_lock(&ctx->mutex);
10668 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
10669 mutex_unlock(&ctx->mutex);
10671 srcu_read_unlock(&pmus_srcu, idx);
10675 static void perf_event_exit_cpu_context(int cpu) { }
10679 int perf_event_exit_cpu(unsigned int cpu)
10681 perf_event_exit_cpu_context(cpu);
10686 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
10690 for_each_online_cpu(cpu)
10691 perf_event_exit_cpu(cpu);
10697 * Run the perf reboot notifier at the very last possible moment so that
10698 * the generic watchdog code runs as long as possible.
10700 static struct notifier_block perf_reboot_notifier = {
10701 .notifier_call = perf_reboot,
10702 .priority = INT_MIN,
10705 void __init perf_event_init(void)
10709 idr_init(&pmu_idr);
10711 perf_event_init_all_cpus();
10712 init_srcu_struct(&pmus_srcu);
10713 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
10714 perf_pmu_register(&perf_cpu_clock, NULL, -1);
10715 perf_pmu_register(&perf_task_clock, NULL, -1);
10716 perf_tp_register();
10717 perf_event_init_cpu(smp_processor_id());
10718 register_reboot_notifier(&perf_reboot_notifier);
10720 ret = init_hw_breakpoint();
10721 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
10724 * Build time assertion that we keep the data_head at the intended
10725 * location. IOW, validation we got the __reserved[] size right.
10727 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
10731 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
10734 struct perf_pmu_events_attr *pmu_attr =
10735 container_of(attr, struct perf_pmu_events_attr, attr);
10737 if (pmu_attr->event_str)
10738 return sprintf(page, "%s\n", pmu_attr->event_str);
10742 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
10744 static int __init perf_event_sysfs_init(void)
10749 mutex_lock(&pmus_lock);
10751 ret = bus_register(&pmu_bus);
10755 list_for_each_entry(pmu, &pmus, entry) {
10756 if (!pmu->name || pmu->type < 0)
10759 ret = pmu_dev_alloc(pmu);
10760 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
10762 pmu_bus_running = 1;
10766 mutex_unlock(&pmus_lock);
10770 device_initcall(perf_event_sysfs_init);
10772 #ifdef CONFIG_CGROUP_PERF
10773 static struct cgroup_subsys_state *
10774 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
10776 struct perf_cgroup *jc;
10778 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
10780 return ERR_PTR(-ENOMEM);
10782 jc->info = alloc_percpu(struct perf_cgroup_info);
10785 return ERR_PTR(-ENOMEM);
10791 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
10793 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
10795 free_percpu(jc->info);
10799 static int __perf_cgroup_move(void *info)
10801 struct task_struct *task = info;
10803 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
10808 static void perf_cgroup_attach(struct cgroup_taskset *tset)
10810 struct task_struct *task;
10811 struct cgroup_subsys_state *css;
10813 cgroup_taskset_for_each(task, css, tset)
10814 task_function_call(task, __perf_cgroup_move, task);
10817 struct cgroup_subsys perf_event_cgrp_subsys = {
10818 .css_alloc = perf_cgroup_css_alloc,
10819 .css_free = perf_cgroup_css_free,
10820 .attach = perf_cgroup_attach,
10822 #endif /* CONFIG_CGROUP_PERF */