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>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
118 } while (ret == -EAGAIN);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu, remote_function_f func, void *info)
134 struct remote_function_call data = {
138 .ret = -ENXIO, /* No such CPU */
141 smp_call_function_single(cpu, remote_function, &data, 1);
146 static inline struct perf_cpu_context *
147 __get_cpu_context(struct perf_event_context *ctx)
149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
153 struct perf_event_context *ctx)
155 raw_spin_lock(&cpuctx->ctx.lock);
157 raw_spin_lock(&ctx->lock);
160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
161 struct perf_event_context *ctx)
164 raw_spin_unlock(&ctx->lock);
165 raw_spin_unlock(&cpuctx->ctx.lock);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event *event)
172 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
195 struct perf_event_context *, void *);
197 struct event_function_struct {
198 struct perf_event *event;
203 static int event_function(void *info)
205 struct event_function_struct *efs = info;
206 struct perf_event *event = efs->event;
207 struct perf_event_context *ctx = event->ctx;
208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
209 struct perf_event_context *task_ctx = cpuctx->task_ctx;
212 WARN_ON_ONCE(!irqs_disabled());
214 perf_ctx_lock(cpuctx, task_ctx);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx->task != current) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx->is_active);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx != ctx);
239 WARN_ON_ONCE(&cpuctx->ctx != ctx);
242 efs->func(event, cpuctx, ctx, efs->data);
244 perf_ctx_unlock(cpuctx, task_ctx);
249 static void event_function_call(struct perf_event *event, event_f func, void *data)
251 struct perf_event_context *ctx = event->ctx;
252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
253 struct event_function_struct efs = {
259 if (!event->parent) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx->mutex);
269 cpu_function_call(event->cpu, event_function, &efs);
273 if (task == TASK_TOMBSTONE)
277 if (!task_function_call(task, event_function, &efs))
280 raw_spin_lock_irq(&ctx->lock);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task == TASK_TOMBSTONE) {
287 raw_spin_unlock_irq(&ctx->lock);
290 if (ctx->is_active) {
291 raw_spin_unlock_irq(&ctx->lock);
294 func(event, NULL, ctx, data);
295 raw_spin_unlock_irq(&ctx->lock);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event *event, event_f func, void *data)
304 struct perf_event_context *ctx = event->ctx;
305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
306 struct task_struct *task = READ_ONCE(ctx->task);
307 struct perf_event_context *task_ctx = NULL;
309 WARN_ON_ONCE(!irqs_disabled());
312 if (task == TASK_TOMBSTONE)
318 perf_ctx_lock(cpuctx, task_ctx);
321 if (task == TASK_TOMBSTONE)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx->is_active) {
331 if (WARN_ON_ONCE(task != current))
334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
338 WARN_ON_ONCE(&cpuctx->ctx != ctx);
341 func(event, cpuctx, ctx, data);
343 perf_ctx_unlock(cpuctx, task_ctx);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE = 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct *work);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
375 static DEFINE_MUTEX(perf_sched_mutex);
376 static atomic_t perf_sched_count;
378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
382 static atomic_t nr_mmap_events __read_mostly;
383 static atomic_t nr_comm_events __read_mostly;
384 static atomic_t nr_namespaces_events __read_mostly;
385 static atomic_t nr_task_events __read_mostly;
386 static atomic_t nr_freq_events __read_mostly;
387 static atomic_t nr_switch_events __read_mostly;
389 static LIST_HEAD(pmus);
390 static DEFINE_MUTEX(pmus_lock);
391 static struct srcu_struct pmus_srcu;
392 static cpumask_var_t perf_online_mask;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly = 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
415 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
416 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
418 static int perf_sample_allowed_ns __read_mostly =
419 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp = perf_sample_period_ns;
425 tmp *= sysctl_perf_cpu_time_max_percent;
426 tmp = div_u64(tmp, 100);
430 WRITE_ONCE(perf_sample_allowed_ns, tmp);
433 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
435 int perf_proc_update_handler(struct ctl_table *table, int write,
436 void __user *buffer, size_t *lenp,
439 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
445 * If throttling is disabled don't allow the write:
447 if (sysctl_perf_cpu_time_max_percent == 100 ||
448 sysctl_perf_cpu_time_max_percent == 0)
451 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
452 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
461 void __user *buffer, size_t *lenp,
464 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
469 if (sysctl_perf_cpu_time_max_percent == 100 ||
470 sysctl_perf_cpu_time_max_percent == 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64, running_sample_length);
490 static u64 __report_avg;
491 static u64 __report_allowed;
493 static void perf_duration_warn(struct irq_work *w)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg, __report_allowed,
499 sysctl_perf_event_sample_rate);
502 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504 void perf_sample_event_took(u64 sample_len_ns)
506 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
514 /* Decay the counter by 1 average sample. */
515 running_len = __this_cpu_read(running_sample_length);
516 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
517 running_len += sample_len_ns;
518 __this_cpu_write(running_sample_length, running_len);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
526 if (avg_len <= max_len)
529 __report_avg = avg_len;
530 __report_allowed = max_len;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len += avg_len / 4;
536 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
542 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
543 WRITE_ONCE(max_samples_per_tick, max);
545 sysctl_perf_event_sample_rate = max * HZ;
546 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548 if (!irq_work_queue(&perf_duration_work)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg, __report_allowed,
552 sysctl_perf_event_sample_rate);
556 static atomic64_t perf_event_id;
558 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
559 enum event_type_t event_type);
561 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
562 enum event_type_t event_type,
563 struct task_struct *task);
565 static void update_context_time(struct perf_event_context *ctx);
566 static u64 perf_event_time(struct perf_event *event);
568 void __weak perf_event_print_debug(void) { }
570 extern __weak const char *perf_pmu_name(void)
575 static inline u64 perf_clock(void)
577 return local_clock();
580 static inline u64 perf_event_clock(struct perf_event *event)
582 return event->clock();
585 #ifdef CONFIG_CGROUP_PERF
588 perf_cgroup_match(struct perf_event *event)
590 struct perf_event_context *ctx = event->ctx;
591 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
593 /* @event doesn't care about cgroup */
597 /* wants specific cgroup scope but @cpuctx isn't associated with any */
602 * Cgroup scoping is recursive. An event enabled for a cgroup is
603 * also enabled for all its descendant cgroups. If @cpuctx's
604 * cgroup is a descendant of @event's (the test covers identity
605 * case), it's a match.
607 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
608 event->cgrp->css.cgroup);
611 static inline void perf_detach_cgroup(struct perf_event *event)
613 css_put(&event->cgrp->css);
617 static inline int is_cgroup_event(struct perf_event *event)
619 return event->cgrp != NULL;
622 static inline u64 perf_cgroup_event_time(struct perf_event *event)
624 struct perf_cgroup_info *t;
626 t = per_cpu_ptr(event->cgrp->info, event->cpu);
630 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
632 struct perf_cgroup_info *info;
637 info = this_cpu_ptr(cgrp->info);
639 info->time += now - info->timestamp;
640 info->timestamp = now;
643 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
645 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
647 __update_cgrp_time(cgrp_out);
650 static inline void update_cgrp_time_from_event(struct perf_event *event)
652 struct perf_cgroup *cgrp;
655 * ensure we access cgroup data only when needed and
656 * when we know the cgroup is pinned (css_get)
658 if (!is_cgroup_event(event))
661 cgrp = perf_cgroup_from_task(current, event->ctx);
663 * Do not update time when cgroup is not active
665 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
666 __update_cgrp_time(event->cgrp);
670 perf_cgroup_set_timestamp(struct task_struct *task,
671 struct perf_event_context *ctx)
673 struct perf_cgroup *cgrp;
674 struct perf_cgroup_info *info;
677 * ctx->lock held by caller
678 * ensure we do not access cgroup data
679 * unless we have the cgroup pinned (css_get)
681 if (!task || !ctx->nr_cgroups)
684 cgrp = perf_cgroup_from_task(task, ctx);
685 info = this_cpu_ptr(cgrp->info);
686 info->timestamp = ctx->timestamp;
689 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
691 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
692 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
695 * reschedule events based on the cgroup constraint of task.
697 * mode SWOUT : schedule out everything
698 * mode SWIN : schedule in based on cgroup for next
700 static void perf_cgroup_switch(struct task_struct *task, int mode)
702 struct perf_cpu_context *cpuctx;
703 struct list_head *list;
707 * Disable interrupts and preemption to avoid this CPU's
708 * cgrp_cpuctx_entry to change under us.
710 local_irq_save(flags);
712 list = this_cpu_ptr(&cgrp_cpuctx_list);
713 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
714 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
716 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
717 perf_pmu_disable(cpuctx->ctx.pmu);
719 if (mode & PERF_CGROUP_SWOUT) {
720 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
722 * must not be done before ctxswout due
723 * to event_filter_match() in event_sched_out()
728 if (mode & PERF_CGROUP_SWIN) {
729 WARN_ON_ONCE(cpuctx->cgrp);
731 * set cgrp before ctxsw in to allow
732 * event_filter_match() to not have to pass
734 * we pass the cpuctx->ctx to perf_cgroup_from_task()
735 * because cgorup events are only per-cpu
737 cpuctx->cgrp = perf_cgroup_from_task(task,
739 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
741 perf_pmu_enable(cpuctx->ctx.pmu);
742 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
745 local_irq_restore(flags);
748 static inline void perf_cgroup_sched_out(struct task_struct *task,
749 struct task_struct *next)
751 struct perf_cgroup *cgrp1;
752 struct perf_cgroup *cgrp2 = NULL;
756 * we come here when we know perf_cgroup_events > 0
757 * we do not need to pass the ctx here because we know
758 * we are holding the rcu lock
760 cgrp1 = perf_cgroup_from_task(task, NULL);
761 cgrp2 = perf_cgroup_from_task(next, NULL);
764 * only schedule out current cgroup events if we know
765 * that we are switching to a different cgroup. Otherwise,
766 * do no touch the cgroup events.
769 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
774 static inline void perf_cgroup_sched_in(struct task_struct *prev,
775 struct task_struct *task)
777 struct perf_cgroup *cgrp1;
778 struct perf_cgroup *cgrp2 = NULL;
782 * we come here when we know perf_cgroup_events > 0
783 * we do not need to pass the ctx here because we know
784 * we are holding the rcu lock
786 cgrp1 = perf_cgroup_from_task(task, NULL);
787 cgrp2 = perf_cgroup_from_task(prev, NULL);
790 * only need to schedule in cgroup events if we are changing
791 * cgroup during ctxsw. Cgroup events were not scheduled
792 * out of ctxsw out if that was not the case.
795 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
800 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
801 struct perf_event_attr *attr,
802 struct perf_event *group_leader)
804 struct perf_cgroup *cgrp;
805 struct cgroup_subsys_state *css;
806 struct fd f = fdget(fd);
812 css = css_tryget_online_from_dir(f.file->f_path.dentry,
813 &perf_event_cgrp_subsys);
819 cgrp = container_of(css, struct perf_cgroup, css);
823 * all events in a group must monitor
824 * the same cgroup because a task belongs
825 * to only one perf cgroup at a time
827 if (group_leader && group_leader->cgrp != cgrp) {
828 perf_detach_cgroup(event);
837 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
839 struct perf_cgroup_info *t;
840 t = per_cpu_ptr(event->cgrp->info, event->cpu);
841 event->shadow_ctx_time = now - t->timestamp;
845 perf_cgroup_defer_enabled(struct perf_event *event)
848 * when the current task's perf cgroup does not match
849 * the event's, we need to remember to call the
850 * perf_mark_enable() function the first time a task with
851 * a matching perf cgroup is scheduled in.
853 if (is_cgroup_event(event) && !perf_cgroup_match(event))
854 event->cgrp_defer_enabled = 1;
858 perf_cgroup_mark_enabled(struct perf_event *event,
859 struct perf_event_context *ctx)
861 struct perf_event *sub;
862 u64 tstamp = perf_event_time(event);
864 if (!event->cgrp_defer_enabled)
867 event->cgrp_defer_enabled = 0;
869 event->tstamp_enabled = tstamp - event->total_time_enabled;
870 list_for_each_entry(sub, &event->sibling_list, group_entry) {
871 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
872 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
873 sub->cgrp_defer_enabled = 0;
879 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
880 * cleared when last cgroup event is removed.
883 list_update_cgroup_event(struct perf_event *event,
884 struct perf_event_context *ctx, bool add)
886 struct perf_cpu_context *cpuctx;
887 struct list_head *cpuctx_entry;
889 if (!is_cgroup_event(event))
892 if (add && ctx->nr_cgroups++)
894 else if (!add && --ctx->nr_cgroups)
897 * Because cgroup events are always per-cpu events,
898 * this will always be called from the right CPU.
900 cpuctx = __get_cpu_context(ctx);
901 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
902 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
904 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
906 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
907 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
910 list_del(cpuctx_entry);
915 #else /* !CONFIG_CGROUP_PERF */
918 perf_cgroup_match(struct perf_event *event)
923 static inline void perf_detach_cgroup(struct perf_event *event)
926 static inline int is_cgroup_event(struct perf_event *event)
931 static inline void update_cgrp_time_from_event(struct perf_event *event)
935 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
939 static inline void perf_cgroup_sched_out(struct task_struct *task,
940 struct task_struct *next)
944 static inline void perf_cgroup_sched_in(struct task_struct *prev,
945 struct task_struct *task)
949 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
950 struct perf_event_attr *attr,
951 struct perf_event *group_leader)
957 perf_cgroup_set_timestamp(struct task_struct *task,
958 struct perf_event_context *ctx)
963 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
968 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
972 static inline u64 perf_cgroup_event_time(struct perf_event *event)
978 perf_cgroup_defer_enabled(struct perf_event *event)
983 perf_cgroup_mark_enabled(struct perf_event *event,
984 struct perf_event_context *ctx)
989 list_update_cgroup_event(struct perf_event *event,
990 struct perf_event_context *ctx, bool add)
997 * set default to be dependent on timer tick just
1000 #define PERF_CPU_HRTIMER (1000 / HZ)
1002 * function must be called with interrupts disabled
1004 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1006 struct perf_cpu_context *cpuctx;
1009 WARN_ON(!irqs_disabled());
1011 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1012 rotations = perf_rotate_context(cpuctx);
1014 raw_spin_lock(&cpuctx->hrtimer_lock);
1016 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1018 cpuctx->hrtimer_active = 0;
1019 raw_spin_unlock(&cpuctx->hrtimer_lock);
1021 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1024 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1026 struct hrtimer *timer = &cpuctx->hrtimer;
1027 struct pmu *pmu = cpuctx->ctx.pmu;
1030 /* no multiplexing needed for SW PMU */
1031 if (pmu->task_ctx_nr == perf_sw_context)
1035 * check default is sane, if not set then force to
1036 * default interval (1/tick)
1038 interval = pmu->hrtimer_interval_ms;
1040 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1042 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1044 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1045 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1046 timer->function = perf_mux_hrtimer_handler;
1049 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1051 struct hrtimer *timer = &cpuctx->hrtimer;
1052 struct pmu *pmu = cpuctx->ctx.pmu;
1053 unsigned long flags;
1055 /* not for SW PMU */
1056 if (pmu->task_ctx_nr == perf_sw_context)
1059 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1060 if (!cpuctx->hrtimer_active) {
1061 cpuctx->hrtimer_active = 1;
1062 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1063 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1065 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1070 void perf_pmu_disable(struct pmu *pmu)
1072 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1074 pmu->pmu_disable(pmu);
1077 void perf_pmu_enable(struct pmu *pmu)
1079 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1081 pmu->pmu_enable(pmu);
1084 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1087 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1088 * perf_event_task_tick() are fully serialized because they're strictly cpu
1089 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1090 * disabled, while perf_event_task_tick is called from IRQ context.
1092 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1094 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1096 WARN_ON(!irqs_disabled());
1098 WARN_ON(!list_empty(&ctx->active_ctx_list));
1100 list_add(&ctx->active_ctx_list, head);
1103 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1105 WARN_ON(!irqs_disabled());
1107 WARN_ON(list_empty(&ctx->active_ctx_list));
1109 list_del_init(&ctx->active_ctx_list);
1112 static void get_ctx(struct perf_event_context *ctx)
1114 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1117 static void free_ctx(struct rcu_head *head)
1119 struct perf_event_context *ctx;
1121 ctx = container_of(head, struct perf_event_context, rcu_head);
1122 kfree(ctx->task_ctx_data);
1126 static void put_ctx(struct perf_event_context *ctx)
1128 if (atomic_dec_and_test(&ctx->refcount)) {
1129 if (ctx->parent_ctx)
1130 put_ctx(ctx->parent_ctx);
1131 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1132 put_task_struct(ctx->task);
1133 call_rcu(&ctx->rcu_head, free_ctx);
1138 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1139 * perf_pmu_migrate_context() we need some magic.
1141 * Those places that change perf_event::ctx will hold both
1142 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1144 * Lock ordering is by mutex address. There are two other sites where
1145 * perf_event_context::mutex nests and those are:
1147 * - perf_event_exit_task_context() [ child , 0 ]
1148 * perf_event_exit_event()
1149 * put_event() [ parent, 1 ]
1151 * - perf_event_init_context() [ parent, 0 ]
1152 * inherit_task_group()
1155 * perf_event_alloc()
1157 * perf_try_init_event() [ child , 1 ]
1159 * While it appears there is an obvious deadlock here -- the parent and child
1160 * nesting levels are inverted between the two. This is in fact safe because
1161 * life-time rules separate them. That is an exiting task cannot fork, and a
1162 * spawning task cannot (yet) exit.
1164 * But remember that that these are parent<->child context relations, and
1165 * migration does not affect children, therefore these two orderings should not
1168 * The change in perf_event::ctx does not affect children (as claimed above)
1169 * because the sys_perf_event_open() case will install a new event and break
1170 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1171 * concerned with cpuctx and that doesn't have children.
1173 * The places that change perf_event::ctx will issue:
1175 * perf_remove_from_context();
1176 * synchronize_rcu();
1177 * perf_install_in_context();
1179 * to affect the change. The remove_from_context() + synchronize_rcu() should
1180 * quiesce the event, after which we can install it in the new location. This
1181 * means that only external vectors (perf_fops, prctl) can perturb the event
1182 * while in transit. Therefore all such accessors should also acquire
1183 * perf_event_context::mutex to serialize against this.
1185 * However; because event->ctx can change while we're waiting to acquire
1186 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1191 * task_struct::perf_event_mutex
1192 * perf_event_context::mutex
1193 * perf_event::child_mutex;
1194 * perf_event_context::lock
1195 * perf_event::mmap_mutex
1198 static struct perf_event_context *
1199 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1201 struct perf_event_context *ctx;
1205 ctx = ACCESS_ONCE(event->ctx);
1206 if (!atomic_inc_not_zero(&ctx->refcount)) {
1212 mutex_lock_nested(&ctx->mutex, nesting);
1213 if (event->ctx != ctx) {
1214 mutex_unlock(&ctx->mutex);
1222 static inline struct perf_event_context *
1223 perf_event_ctx_lock(struct perf_event *event)
1225 return perf_event_ctx_lock_nested(event, 0);
1228 static void perf_event_ctx_unlock(struct perf_event *event,
1229 struct perf_event_context *ctx)
1231 mutex_unlock(&ctx->mutex);
1236 * This must be done under the ctx->lock, such as to serialize against
1237 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1238 * calling scheduler related locks and ctx->lock nests inside those.
1240 static __must_check struct perf_event_context *
1241 unclone_ctx(struct perf_event_context *ctx)
1243 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1245 lockdep_assert_held(&ctx->lock);
1248 ctx->parent_ctx = NULL;
1254 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1259 * only top level events have the pid namespace they were created in
1262 event = event->parent;
1264 nr = __task_pid_nr_ns(p, type, event->ns);
1265 /* avoid -1 if it is idle thread or runs in another ns */
1266 if (!nr && !pid_alive(p))
1271 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1273 return perf_event_pid_type(event, p, __PIDTYPE_TGID);
1276 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1278 return perf_event_pid_type(event, p, PIDTYPE_PID);
1282 * If we inherit events we want to return the parent event id
1285 static u64 primary_event_id(struct perf_event *event)
1290 id = event->parent->id;
1296 * Get the perf_event_context for a task and lock it.
1298 * This has to cope with with the fact that until it is locked,
1299 * the context could get moved to another task.
1301 static struct perf_event_context *
1302 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1304 struct perf_event_context *ctx;
1308 * One of the few rules of preemptible RCU is that one cannot do
1309 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1310 * part of the read side critical section was irqs-enabled -- see
1311 * rcu_read_unlock_special().
1313 * Since ctx->lock nests under rq->lock we must ensure the entire read
1314 * side critical section has interrupts disabled.
1316 local_irq_save(*flags);
1318 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1321 * If this context is a clone of another, it might
1322 * get swapped for another underneath us by
1323 * perf_event_task_sched_out, though the
1324 * rcu_read_lock() protects us from any context
1325 * getting freed. Lock the context and check if it
1326 * got swapped before we could get the lock, and retry
1327 * if so. If we locked the right context, then it
1328 * can't get swapped on us any more.
1330 raw_spin_lock(&ctx->lock);
1331 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1332 raw_spin_unlock(&ctx->lock);
1334 local_irq_restore(*flags);
1338 if (ctx->task == TASK_TOMBSTONE ||
1339 !atomic_inc_not_zero(&ctx->refcount)) {
1340 raw_spin_unlock(&ctx->lock);
1343 WARN_ON_ONCE(ctx->task != task);
1348 local_irq_restore(*flags);
1353 * Get the context for a task and increment its pin_count so it
1354 * can't get swapped to another task. This also increments its
1355 * reference count so that the context can't get freed.
1357 static struct perf_event_context *
1358 perf_pin_task_context(struct task_struct *task, int ctxn)
1360 struct perf_event_context *ctx;
1361 unsigned long flags;
1363 ctx = perf_lock_task_context(task, ctxn, &flags);
1366 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1371 static void perf_unpin_context(struct perf_event_context *ctx)
1373 unsigned long flags;
1375 raw_spin_lock_irqsave(&ctx->lock, flags);
1377 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1381 * Update the record of the current time in a context.
1383 static void update_context_time(struct perf_event_context *ctx)
1385 u64 now = perf_clock();
1387 ctx->time += now - ctx->timestamp;
1388 ctx->timestamp = now;
1391 static u64 perf_event_time(struct perf_event *event)
1393 struct perf_event_context *ctx = event->ctx;
1395 if (is_cgroup_event(event))
1396 return perf_cgroup_event_time(event);
1398 return ctx ? ctx->time : 0;
1402 * Update the total_time_enabled and total_time_running fields for a event.
1404 static void update_event_times(struct perf_event *event)
1406 struct perf_event_context *ctx = event->ctx;
1409 lockdep_assert_held(&ctx->lock);
1411 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1412 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1416 * in cgroup mode, time_enabled represents
1417 * the time the event was enabled AND active
1418 * tasks were in the monitored cgroup. This is
1419 * independent of the activity of the context as
1420 * there may be a mix of cgroup and non-cgroup events.
1422 * That is why we treat cgroup events differently
1425 if (is_cgroup_event(event))
1426 run_end = perf_cgroup_event_time(event);
1427 else if (ctx->is_active)
1428 run_end = ctx->time;
1430 run_end = event->tstamp_stopped;
1432 event->total_time_enabled = run_end - event->tstamp_enabled;
1434 if (event->state == PERF_EVENT_STATE_INACTIVE)
1435 run_end = event->tstamp_stopped;
1437 run_end = perf_event_time(event);
1439 event->total_time_running = run_end - event->tstamp_running;
1444 * Update total_time_enabled and total_time_running for all events in a group.
1446 static void update_group_times(struct perf_event *leader)
1448 struct perf_event *event;
1450 update_event_times(leader);
1451 list_for_each_entry(event, &leader->sibling_list, group_entry)
1452 update_event_times(event);
1455 static enum event_type_t get_event_type(struct perf_event *event)
1457 struct perf_event_context *ctx = event->ctx;
1458 enum event_type_t event_type;
1460 lockdep_assert_held(&ctx->lock);
1463 * It's 'group type', really, because if our group leader is
1464 * pinned, so are we.
1466 if (event->group_leader != event)
1467 event = event->group_leader;
1469 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1471 event_type |= EVENT_CPU;
1476 static struct list_head *
1477 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1479 if (event->attr.pinned)
1480 return &ctx->pinned_groups;
1482 return &ctx->flexible_groups;
1486 * Add a event from the lists for its context.
1487 * Must be called with ctx->mutex and ctx->lock held.
1490 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1492 lockdep_assert_held(&ctx->lock);
1494 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1495 event->attach_state |= PERF_ATTACH_CONTEXT;
1498 * If we're a stand alone event or group leader, we go to the context
1499 * list, group events are kept attached to the group so that
1500 * perf_group_detach can, at all times, locate all siblings.
1502 if (event->group_leader == event) {
1503 struct list_head *list;
1505 event->group_caps = event->event_caps;
1507 list = ctx_group_list(event, ctx);
1508 list_add_tail(&event->group_entry, list);
1511 list_update_cgroup_event(event, ctx, true);
1513 list_add_rcu(&event->event_entry, &ctx->event_list);
1515 if (event->attr.inherit_stat)
1522 * Initialize event state based on the perf_event_attr::disabled.
1524 static inline void perf_event__state_init(struct perf_event *event)
1526 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1527 PERF_EVENT_STATE_INACTIVE;
1530 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1532 int entry = sizeof(u64); /* value */
1536 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1537 size += sizeof(u64);
1539 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1540 size += sizeof(u64);
1542 if (event->attr.read_format & PERF_FORMAT_ID)
1543 entry += sizeof(u64);
1545 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1547 size += sizeof(u64);
1551 event->read_size = size;
1554 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1556 struct perf_sample_data *data;
1559 if (sample_type & PERF_SAMPLE_IP)
1560 size += sizeof(data->ip);
1562 if (sample_type & PERF_SAMPLE_ADDR)
1563 size += sizeof(data->addr);
1565 if (sample_type & PERF_SAMPLE_PERIOD)
1566 size += sizeof(data->period);
1568 if (sample_type & PERF_SAMPLE_WEIGHT)
1569 size += sizeof(data->weight);
1571 if (sample_type & PERF_SAMPLE_READ)
1572 size += event->read_size;
1574 if (sample_type & PERF_SAMPLE_DATA_SRC)
1575 size += sizeof(data->data_src.val);
1577 if (sample_type & PERF_SAMPLE_TRANSACTION)
1578 size += sizeof(data->txn);
1580 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1581 size += sizeof(data->phys_addr);
1583 event->header_size = size;
1587 * Called at perf_event creation and when events are attached/detached from a
1590 static void perf_event__header_size(struct perf_event *event)
1592 __perf_event_read_size(event,
1593 event->group_leader->nr_siblings);
1594 __perf_event_header_size(event, event->attr.sample_type);
1597 static void perf_event__id_header_size(struct perf_event *event)
1599 struct perf_sample_data *data;
1600 u64 sample_type = event->attr.sample_type;
1603 if (sample_type & PERF_SAMPLE_TID)
1604 size += sizeof(data->tid_entry);
1606 if (sample_type & PERF_SAMPLE_TIME)
1607 size += sizeof(data->time);
1609 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1610 size += sizeof(data->id);
1612 if (sample_type & PERF_SAMPLE_ID)
1613 size += sizeof(data->id);
1615 if (sample_type & PERF_SAMPLE_STREAM_ID)
1616 size += sizeof(data->stream_id);
1618 if (sample_type & PERF_SAMPLE_CPU)
1619 size += sizeof(data->cpu_entry);
1621 event->id_header_size = size;
1624 static bool perf_event_validate_size(struct perf_event *event)
1627 * The values computed here will be over-written when we actually
1630 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1631 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1632 perf_event__id_header_size(event);
1635 * Sum the lot; should not exceed the 64k limit we have on records.
1636 * Conservative limit to allow for callchains and other variable fields.
1638 if (event->read_size + event->header_size +
1639 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1645 static void perf_group_attach(struct perf_event *event)
1647 struct perf_event *group_leader = event->group_leader, *pos;
1649 lockdep_assert_held(&event->ctx->lock);
1652 * We can have double attach due to group movement in perf_event_open.
1654 if (event->attach_state & PERF_ATTACH_GROUP)
1657 event->attach_state |= PERF_ATTACH_GROUP;
1659 if (group_leader == event)
1662 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1664 group_leader->group_caps &= event->event_caps;
1666 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1667 group_leader->nr_siblings++;
1669 perf_event__header_size(group_leader);
1671 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1672 perf_event__header_size(pos);
1676 * Remove a event from the lists for its context.
1677 * Must be called with ctx->mutex and ctx->lock held.
1680 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1682 WARN_ON_ONCE(event->ctx != ctx);
1683 lockdep_assert_held(&ctx->lock);
1686 * We can have double detach due to exit/hot-unplug + close.
1688 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1691 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1693 list_update_cgroup_event(event, ctx, false);
1696 if (event->attr.inherit_stat)
1699 list_del_rcu(&event->event_entry);
1701 if (event->group_leader == event)
1702 list_del_init(&event->group_entry);
1704 update_group_times(event);
1707 * If event was in error state, then keep it
1708 * that way, otherwise bogus counts will be
1709 * returned on read(). The only way to get out
1710 * of error state is by explicit re-enabling
1713 if (event->state > PERF_EVENT_STATE_OFF)
1714 event->state = PERF_EVENT_STATE_OFF;
1719 static void perf_group_detach(struct perf_event *event)
1721 struct perf_event *sibling, *tmp;
1722 struct list_head *list = NULL;
1724 lockdep_assert_held(&event->ctx->lock);
1727 * We can have double detach due to exit/hot-unplug + close.
1729 if (!(event->attach_state & PERF_ATTACH_GROUP))
1732 event->attach_state &= ~PERF_ATTACH_GROUP;
1735 * If this is a sibling, remove it from its group.
1737 if (event->group_leader != event) {
1738 list_del_init(&event->group_entry);
1739 event->group_leader->nr_siblings--;
1743 if (!list_empty(&event->group_entry))
1744 list = &event->group_entry;
1747 * If this was a group event with sibling events then
1748 * upgrade the siblings to singleton events by adding them
1749 * to whatever list we are on.
1751 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1753 list_move_tail(&sibling->group_entry, list);
1754 sibling->group_leader = sibling;
1756 /* Inherit group flags from the previous leader */
1757 sibling->group_caps = event->group_caps;
1759 WARN_ON_ONCE(sibling->ctx != event->ctx);
1763 perf_event__header_size(event->group_leader);
1765 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1766 perf_event__header_size(tmp);
1769 static bool is_orphaned_event(struct perf_event *event)
1771 return event->state == PERF_EVENT_STATE_DEAD;
1774 static inline int __pmu_filter_match(struct perf_event *event)
1776 struct pmu *pmu = event->pmu;
1777 return pmu->filter_match ? pmu->filter_match(event) : 1;
1781 * Check whether we should attempt to schedule an event group based on
1782 * PMU-specific filtering. An event group can consist of HW and SW events,
1783 * potentially with a SW leader, so we must check all the filters, to
1784 * determine whether a group is schedulable:
1786 static inline int pmu_filter_match(struct perf_event *event)
1788 struct perf_event *child;
1790 if (!__pmu_filter_match(event))
1793 list_for_each_entry(child, &event->sibling_list, group_entry) {
1794 if (!__pmu_filter_match(child))
1802 event_filter_match(struct perf_event *event)
1804 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1805 perf_cgroup_match(event) && pmu_filter_match(event);
1809 event_sched_out(struct perf_event *event,
1810 struct perf_cpu_context *cpuctx,
1811 struct perf_event_context *ctx)
1813 u64 tstamp = perf_event_time(event);
1816 WARN_ON_ONCE(event->ctx != ctx);
1817 lockdep_assert_held(&ctx->lock);
1820 * An event which could not be activated because of
1821 * filter mismatch still needs to have its timings
1822 * maintained, otherwise bogus information is return
1823 * via read() for time_enabled, time_running:
1825 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1826 !event_filter_match(event)) {
1827 delta = tstamp - event->tstamp_stopped;
1828 event->tstamp_running += delta;
1829 event->tstamp_stopped = tstamp;
1832 if (event->state != PERF_EVENT_STATE_ACTIVE)
1835 perf_pmu_disable(event->pmu);
1837 event->tstamp_stopped = tstamp;
1838 event->pmu->del(event, 0);
1840 event->state = PERF_EVENT_STATE_INACTIVE;
1841 if (event->pending_disable) {
1842 event->pending_disable = 0;
1843 event->state = PERF_EVENT_STATE_OFF;
1846 if (!is_software_event(event))
1847 cpuctx->active_oncpu--;
1848 if (!--ctx->nr_active)
1849 perf_event_ctx_deactivate(ctx);
1850 if (event->attr.freq && event->attr.sample_freq)
1852 if (event->attr.exclusive || !cpuctx->active_oncpu)
1853 cpuctx->exclusive = 0;
1855 perf_pmu_enable(event->pmu);
1859 group_sched_out(struct perf_event *group_event,
1860 struct perf_cpu_context *cpuctx,
1861 struct perf_event_context *ctx)
1863 struct perf_event *event;
1864 int state = group_event->state;
1866 perf_pmu_disable(ctx->pmu);
1868 event_sched_out(group_event, cpuctx, ctx);
1871 * Schedule out siblings (if any):
1873 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1874 event_sched_out(event, cpuctx, ctx);
1876 perf_pmu_enable(ctx->pmu);
1878 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1879 cpuctx->exclusive = 0;
1882 #define DETACH_GROUP 0x01UL
1885 * Cross CPU call to remove a performance event
1887 * We disable the event on the hardware level first. After that we
1888 * remove it from the context list.
1891 __perf_remove_from_context(struct perf_event *event,
1892 struct perf_cpu_context *cpuctx,
1893 struct perf_event_context *ctx,
1896 unsigned long flags = (unsigned long)info;
1898 event_sched_out(event, cpuctx, ctx);
1899 if (flags & DETACH_GROUP)
1900 perf_group_detach(event);
1901 list_del_event(event, ctx);
1903 if (!ctx->nr_events && ctx->is_active) {
1906 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1907 cpuctx->task_ctx = NULL;
1913 * Remove the event from a task's (or a CPU's) list of events.
1915 * If event->ctx is a cloned context, callers must make sure that
1916 * every task struct that event->ctx->task could possibly point to
1917 * remains valid. This is OK when called from perf_release since
1918 * that only calls us on the top-level context, which can't be a clone.
1919 * When called from perf_event_exit_task, it's OK because the
1920 * context has been detached from its task.
1922 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1924 struct perf_event_context *ctx = event->ctx;
1926 lockdep_assert_held(&ctx->mutex);
1928 event_function_call(event, __perf_remove_from_context, (void *)flags);
1931 * The above event_function_call() can NO-OP when it hits
1932 * TASK_TOMBSTONE. In that case we must already have been detached
1933 * from the context (by perf_event_exit_event()) but the grouping
1934 * might still be in-tact.
1936 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1937 if ((flags & DETACH_GROUP) &&
1938 (event->attach_state & PERF_ATTACH_GROUP)) {
1940 * Since in that case we cannot possibly be scheduled, simply
1943 raw_spin_lock_irq(&ctx->lock);
1944 perf_group_detach(event);
1945 raw_spin_unlock_irq(&ctx->lock);
1950 * Cross CPU call to disable a performance event
1952 static void __perf_event_disable(struct perf_event *event,
1953 struct perf_cpu_context *cpuctx,
1954 struct perf_event_context *ctx,
1957 if (event->state < PERF_EVENT_STATE_INACTIVE)
1960 update_context_time(ctx);
1961 update_cgrp_time_from_event(event);
1962 update_group_times(event);
1963 if (event == event->group_leader)
1964 group_sched_out(event, cpuctx, ctx);
1966 event_sched_out(event, cpuctx, ctx);
1967 event->state = PERF_EVENT_STATE_OFF;
1973 * If event->ctx is a cloned context, callers must make sure that
1974 * every task struct that event->ctx->task could possibly point to
1975 * remains valid. This condition is satisifed when called through
1976 * perf_event_for_each_child or perf_event_for_each because they
1977 * hold the top-level event's child_mutex, so any descendant that
1978 * goes to exit will block in perf_event_exit_event().
1980 * When called from perf_pending_event it's OK because event->ctx
1981 * is the current context on this CPU and preemption is disabled,
1982 * hence we can't get into perf_event_task_sched_out for this context.
1984 static void _perf_event_disable(struct perf_event *event)
1986 struct perf_event_context *ctx = event->ctx;
1988 raw_spin_lock_irq(&ctx->lock);
1989 if (event->state <= PERF_EVENT_STATE_OFF) {
1990 raw_spin_unlock_irq(&ctx->lock);
1993 raw_spin_unlock_irq(&ctx->lock);
1995 event_function_call(event, __perf_event_disable, NULL);
1998 void perf_event_disable_local(struct perf_event *event)
2000 event_function_local(event, __perf_event_disable, NULL);
2004 * Strictly speaking kernel users cannot create groups and therefore this
2005 * interface does not need the perf_event_ctx_lock() magic.
2007 void perf_event_disable(struct perf_event *event)
2009 struct perf_event_context *ctx;
2011 ctx = perf_event_ctx_lock(event);
2012 _perf_event_disable(event);
2013 perf_event_ctx_unlock(event, ctx);
2015 EXPORT_SYMBOL_GPL(perf_event_disable);
2017 void perf_event_disable_inatomic(struct perf_event *event)
2019 event->pending_disable = 1;
2020 irq_work_queue(&event->pending);
2023 static void perf_set_shadow_time(struct perf_event *event,
2024 struct perf_event_context *ctx,
2028 * use the correct time source for the time snapshot
2030 * We could get by without this by leveraging the
2031 * fact that to get to this function, the caller
2032 * has most likely already called update_context_time()
2033 * and update_cgrp_time_xx() and thus both timestamp
2034 * are identical (or very close). Given that tstamp is,
2035 * already adjusted for cgroup, we could say that:
2036 * tstamp - ctx->timestamp
2038 * tstamp - cgrp->timestamp.
2040 * Then, in perf_output_read(), the calculation would
2041 * work with no changes because:
2042 * - event is guaranteed scheduled in
2043 * - no scheduled out in between
2044 * - thus the timestamp would be the same
2046 * But this is a bit hairy.
2048 * So instead, we have an explicit cgroup call to remain
2049 * within the time time source all along. We believe it
2050 * is cleaner and simpler to understand.
2052 if (is_cgroup_event(event))
2053 perf_cgroup_set_shadow_time(event, tstamp);
2055 event->shadow_ctx_time = tstamp - ctx->timestamp;
2058 #define MAX_INTERRUPTS (~0ULL)
2060 static void perf_log_throttle(struct perf_event *event, int enable);
2061 static void perf_log_itrace_start(struct perf_event *event);
2064 event_sched_in(struct perf_event *event,
2065 struct perf_cpu_context *cpuctx,
2066 struct perf_event_context *ctx)
2068 u64 tstamp = perf_event_time(event);
2071 lockdep_assert_held(&ctx->lock);
2073 if (event->state <= PERF_EVENT_STATE_OFF)
2076 WRITE_ONCE(event->oncpu, smp_processor_id());
2078 * Order event::oncpu write to happen before the ACTIVE state
2082 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2085 * Unthrottle events, since we scheduled we might have missed several
2086 * ticks already, also for a heavily scheduling task there is little
2087 * guarantee it'll get a tick in a timely manner.
2089 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2090 perf_log_throttle(event, 1);
2091 event->hw.interrupts = 0;
2095 * The new state must be visible before we turn it on in the hardware:
2099 perf_pmu_disable(event->pmu);
2101 perf_set_shadow_time(event, ctx, tstamp);
2103 perf_log_itrace_start(event);
2105 if (event->pmu->add(event, PERF_EF_START)) {
2106 event->state = PERF_EVENT_STATE_INACTIVE;
2112 event->tstamp_running += tstamp - event->tstamp_stopped;
2114 if (!is_software_event(event))
2115 cpuctx->active_oncpu++;
2116 if (!ctx->nr_active++)
2117 perf_event_ctx_activate(ctx);
2118 if (event->attr.freq && event->attr.sample_freq)
2121 if (event->attr.exclusive)
2122 cpuctx->exclusive = 1;
2125 perf_pmu_enable(event->pmu);
2131 group_sched_in(struct perf_event *group_event,
2132 struct perf_cpu_context *cpuctx,
2133 struct perf_event_context *ctx)
2135 struct perf_event *event, *partial_group = NULL;
2136 struct pmu *pmu = ctx->pmu;
2137 u64 now = ctx->time;
2138 bool simulate = false;
2140 if (group_event->state == PERF_EVENT_STATE_OFF)
2143 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2145 if (event_sched_in(group_event, cpuctx, ctx)) {
2146 pmu->cancel_txn(pmu);
2147 perf_mux_hrtimer_restart(cpuctx);
2152 * Schedule in siblings as one group (if any):
2154 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2155 if (event_sched_in(event, cpuctx, ctx)) {
2156 partial_group = event;
2161 if (!pmu->commit_txn(pmu))
2166 * Groups can be scheduled in as one unit only, so undo any
2167 * partial group before returning:
2168 * The events up to the failed event are scheduled out normally,
2169 * tstamp_stopped will be updated.
2171 * The failed events and the remaining siblings need to have
2172 * their timings updated as if they had gone thru event_sched_in()
2173 * and event_sched_out(). This is required to get consistent timings
2174 * across the group. This also takes care of the case where the group
2175 * could never be scheduled by ensuring tstamp_stopped is set to mark
2176 * the time the event was actually stopped, such that time delta
2177 * calculation in update_event_times() is correct.
2179 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2180 if (event == partial_group)
2184 event->tstamp_running += now - event->tstamp_stopped;
2185 event->tstamp_stopped = now;
2187 event_sched_out(event, cpuctx, ctx);
2190 event_sched_out(group_event, cpuctx, ctx);
2192 pmu->cancel_txn(pmu);
2194 perf_mux_hrtimer_restart(cpuctx);
2200 * Work out whether we can put this event group on the CPU now.
2202 static int group_can_go_on(struct perf_event *event,
2203 struct perf_cpu_context *cpuctx,
2207 * Groups consisting entirely of software events can always go on.
2209 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2212 * If an exclusive group is already on, no other hardware
2215 if (cpuctx->exclusive)
2218 * If this group is exclusive and there are already
2219 * events on the CPU, it can't go on.
2221 if (event->attr.exclusive && cpuctx->active_oncpu)
2224 * Otherwise, try to add it if all previous groups were able
2231 * Complement to update_event_times(). This computes the tstamp_* values to
2232 * continue 'enabled' state from @now, and effectively discards the time
2233 * between the prior tstamp_stopped and now (as we were in the OFF state, or
2234 * just switched (context) time base).
2236 * This further assumes '@event->state == INACTIVE' (we just came from OFF) and
2237 * cannot have been scheduled in yet. And going into INACTIVE state means
2238 * '@event->tstamp_stopped = @now'.
2240 * Thus given the rules of update_event_times():
2242 * total_time_enabled = tstamp_stopped - tstamp_enabled
2243 * total_time_running = tstamp_stopped - tstamp_running
2245 * We can insert 'tstamp_stopped == now' and reverse them to compute new
2248 static void __perf_event_enable_time(struct perf_event *event, u64 now)
2250 WARN_ON_ONCE(event->state != PERF_EVENT_STATE_INACTIVE);
2252 event->tstamp_stopped = now;
2253 event->tstamp_enabled = now - event->total_time_enabled;
2254 event->tstamp_running = now - event->total_time_running;
2257 static void add_event_to_ctx(struct perf_event *event,
2258 struct perf_event_context *ctx)
2260 u64 tstamp = perf_event_time(event);
2262 list_add_event(event, ctx);
2263 perf_group_attach(event);
2265 * We can be called with event->state == STATE_OFF when we create with
2266 * .disabled = 1. In that case the IOC_ENABLE will call this function.
2268 if (event->state == PERF_EVENT_STATE_INACTIVE)
2269 __perf_event_enable_time(event, tstamp);
2272 static void ctx_sched_out(struct perf_event_context *ctx,
2273 struct perf_cpu_context *cpuctx,
2274 enum event_type_t event_type);
2276 ctx_sched_in(struct perf_event_context *ctx,
2277 struct perf_cpu_context *cpuctx,
2278 enum event_type_t event_type,
2279 struct task_struct *task);
2281 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2282 struct perf_event_context *ctx,
2283 enum event_type_t event_type)
2285 if (!cpuctx->task_ctx)
2288 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2291 ctx_sched_out(ctx, cpuctx, event_type);
2294 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2295 struct perf_event_context *ctx,
2296 struct task_struct *task)
2298 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2300 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2301 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2303 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2307 * We want to maintain the following priority of scheduling:
2308 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2309 * - task pinned (EVENT_PINNED)
2310 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2311 * - task flexible (EVENT_FLEXIBLE).
2313 * In order to avoid unscheduling and scheduling back in everything every
2314 * time an event is added, only do it for the groups of equal priority and
2317 * This can be called after a batch operation on task events, in which case
2318 * event_type is a bit mask of the types of events involved. For CPU events,
2319 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2321 static void ctx_resched(struct perf_cpu_context *cpuctx,
2322 struct perf_event_context *task_ctx,
2323 enum event_type_t event_type)
2325 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2326 bool cpu_event = !!(event_type & EVENT_CPU);
2329 * If pinned groups are involved, flexible groups also need to be
2332 if (event_type & EVENT_PINNED)
2333 event_type |= EVENT_FLEXIBLE;
2335 perf_pmu_disable(cpuctx->ctx.pmu);
2337 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2340 * Decide which cpu ctx groups to schedule out based on the types
2341 * of events that caused rescheduling:
2342 * - EVENT_CPU: schedule out corresponding groups;
2343 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2344 * - otherwise, do nothing more.
2347 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2348 else if (ctx_event_type & EVENT_PINNED)
2349 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2351 perf_event_sched_in(cpuctx, task_ctx, current);
2352 perf_pmu_enable(cpuctx->ctx.pmu);
2356 * Cross CPU call to install and enable a performance event
2358 * Very similar to remote_function() + event_function() but cannot assume that
2359 * things like ctx->is_active and cpuctx->task_ctx are set.
2361 static int __perf_install_in_context(void *info)
2363 struct perf_event *event = info;
2364 struct perf_event_context *ctx = event->ctx;
2365 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2366 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2367 bool reprogram = true;
2370 raw_spin_lock(&cpuctx->ctx.lock);
2372 raw_spin_lock(&ctx->lock);
2375 reprogram = (ctx->task == current);
2378 * If the task is running, it must be running on this CPU,
2379 * otherwise we cannot reprogram things.
2381 * If its not running, we don't care, ctx->lock will
2382 * serialize against it becoming runnable.
2384 if (task_curr(ctx->task) && !reprogram) {
2389 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2390 } else if (task_ctx) {
2391 raw_spin_lock(&task_ctx->lock);
2395 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2396 add_event_to_ctx(event, ctx);
2397 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2399 add_event_to_ctx(event, ctx);
2403 perf_ctx_unlock(cpuctx, task_ctx);
2409 * Attach a performance event to a context.
2411 * Very similar to event_function_call, see comment there.
2414 perf_install_in_context(struct perf_event_context *ctx,
2415 struct perf_event *event,
2418 struct task_struct *task = READ_ONCE(ctx->task);
2420 lockdep_assert_held(&ctx->mutex);
2422 if (event->cpu != -1)
2426 * Ensures that if we can observe event->ctx, both the event and ctx
2427 * will be 'complete'. See perf_iterate_sb_cpu().
2429 smp_store_release(&event->ctx, ctx);
2432 cpu_function_call(cpu, __perf_install_in_context, event);
2437 * Should not happen, we validate the ctx is still alive before calling.
2439 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2443 * Installing events is tricky because we cannot rely on ctx->is_active
2444 * to be set in case this is the nr_events 0 -> 1 transition.
2446 * Instead we use task_curr(), which tells us if the task is running.
2447 * However, since we use task_curr() outside of rq::lock, we can race
2448 * against the actual state. This means the result can be wrong.
2450 * If we get a false positive, we retry, this is harmless.
2452 * If we get a false negative, things are complicated. If we are after
2453 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2454 * value must be correct. If we're before, it doesn't matter since
2455 * perf_event_context_sched_in() will program the counter.
2457 * However, this hinges on the remote context switch having observed
2458 * our task->perf_event_ctxp[] store, such that it will in fact take
2459 * ctx::lock in perf_event_context_sched_in().
2461 * We do this by task_function_call(), if the IPI fails to hit the task
2462 * we know any future context switch of task must see the
2463 * perf_event_ctpx[] store.
2467 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2468 * task_cpu() load, such that if the IPI then does not find the task
2469 * running, a future context switch of that task must observe the
2474 if (!task_function_call(task, __perf_install_in_context, event))
2477 raw_spin_lock_irq(&ctx->lock);
2479 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2481 * Cannot happen because we already checked above (which also
2482 * cannot happen), and we hold ctx->mutex, which serializes us
2483 * against perf_event_exit_task_context().
2485 raw_spin_unlock_irq(&ctx->lock);
2489 * If the task is not running, ctx->lock will avoid it becoming so,
2490 * thus we can safely install the event.
2492 if (task_curr(task)) {
2493 raw_spin_unlock_irq(&ctx->lock);
2496 add_event_to_ctx(event, ctx);
2497 raw_spin_unlock_irq(&ctx->lock);
2501 * Put a event into inactive state and update time fields.
2502 * Enabling the leader of a group effectively enables all
2503 * the group members that aren't explicitly disabled, so we
2504 * have to update their ->tstamp_enabled also.
2505 * Note: this works for group members as well as group leaders
2506 * since the non-leader members' sibling_lists will be empty.
2508 static void __perf_event_mark_enabled(struct perf_event *event)
2510 struct perf_event *sub;
2511 u64 tstamp = perf_event_time(event);
2513 event->state = PERF_EVENT_STATE_INACTIVE;
2514 __perf_event_enable_time(event, tstamp);
2515 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2516 /* XXX should not be > INACTIVE if event isn't */
2517 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2518 __perf_event_enable_time(sub, tstamp);
2523 * Cross CPU call to enable a performance event
2525 static void __perf_event_enable(struct perf_event *event,
2526 struct perf_cpu_context *cpuctx,
2527 struct perf_event_context *ctx,
2530 struct perf_event *leader = event->group_leader;
2531 struct perf_event_context *task_ctx;
2533 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2534 event->state <= PERF_EVENT_STATE_ERROR)
2538 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2540 __perf_event_mark_enabled(event);
2542 if (!ctx->is_active)
2545 if (!event_filter_match(event)) {
2546 if (is_cgroup_event(event))
2547 perf_cgroup_defer_enabled(event);
2548 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2553 * If the event is in a group and isn't the group leader,
2554 * then don't put it on unless the group is on.
2556 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2557 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2561 task_ctx = cpuctx->task_ctx;
2563 WARN_ON_ONCE(task_ctx != ctx);
2565 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2571 * If event->ctx is a cloned context, callers must make sure that
2572 * every task struct that event->ctx->task could possibly point to
2573 * remains valid. This condition is satisfied when called through
2574 * perf_event_for_each_child or perf_event_for_each as described
2575 * for perf_event_disable.
2577 static void _perf_event_enable(struct perf_event *event)
2579 struct perf_event_context *ctx = event->ctx;
2581 raw_spin_lock_irq(&ctx->lock);
2582 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2583 event->state < PERF_EVENT_STATE_ERROR) {
2584 raw_spin_unlock_irq(&ctx->lock);
2589 * If the event is in error state, clear that first.
2591 * That way, if we see the event in error state below, we know that it
2592 * has gone back into error state, as distinct from the task having
2593 * been scheduled away before the cross-call arrived.
2595 if (event->state == PERF_EVENT_STATE_ERROR)
2596 event->state = PERF_EVENT_STATE_OFF;
2597 raw_spin_unlock_irq(&ctx->lock);
2599 event_function_call(event, __perf_event_enable, NULL);
2603 * See perf_event_disable();
2605 void perf_event_enable(struct perf_event *event)
2607 struct perf_event_context *ctx;
2609 ctx = perf_event_ctx_lock(event);
2610 _perf_event_enable(event);
2611 perf_event_ctx_unlock(event, ctx);
2613 EXPORT_SYMBOL_GPL(perf_event_enable);
2615 struct stop_event_data {
2616 struct perf_event *event;
2617 unsigned int restart;
2620 static int __perf_event_stop(void *info)
2622 struct stop_event_data *sd = info;
2623 struct perf_event *event = sd->event;
2625 /* if it's already INACTIVE, do nothing */
2626 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2629 /* matches smp_wmb() in event_sched_in() */
2633 * There is a window with interrupts enabled before we get here,
2634 * so we need to check again lest we try to stop another CPU's event.
2636 if (READ_ONCE(event->oncpu) != smp_processor_id())
2639 event->pmu->stop(event, PERF_EF_UPDATE);
2642 * May race with the actual stop (through perf_pmu_output_stop()),
2643 * but it is only used for events with AUX ring buffer, and such
2644 * events will refuse to restart because of rb::aux_mmap_count==0,
2645 * see comments in perf_aux_output_begin().
2647 * Since this is happening on a event-local CPU, no trace is lost
2651 event->pmu->start(event, 0);
2656 static int perf_event_stop(struct perf_event *event, int restart)
2658 struct stop_event_data sd = {
2665 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2668 /* matches smp_wmb() in event_sched_in() */
2672 * We only want to restart ACTIVE events, so if the event goes
2673 * inactive here (event->oncpu==-1), there's nothing more to do;
2674 * fall through with ret==-ENXIO.
2676 ret = cpu_function_call(READ_ONCE(event->oncpu),
2677 __perf_event_stop, &sd);
2678 } while (ret == -EAGAIN);
2684 * In order to contain the amount of racy and tricky in the address filter
2685 * configuration management, it is a two part process:
2687 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2688 * we update the addresses of corresponding vmas in
2689 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2690 * (p2) when an event is scheduled in (pmu::add), it calls
2691 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2692 * if the generation has changed since the previous call.
2694 * If (p1) happens while the event is active, we restart it to force (p2).
2696 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2697 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2699 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2700 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2702 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2705 void perf_event_addr_filters_sync(struct perf_event *event)
2707 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2709 if (!has_addr_filter(event))
2712 raw_spin_lock(&ifh->lock);
2713 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2714 event->pmu->addr_filters_sync(event);
2715 event->hw.addr_filters_gen = event->addr_filters_gen;
2717 raw_spin_unlock(&ifh->lock);
2719 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2721 static int _perf_event_refresh(struct perf_event *event, int refresh)
2724 * not supported on inherited events
2726 if (event->attr.inherit || !is_sampling_event(event))
2729 atomic_add(refresh, &event->event_limit);
2730 _perf_event_enable(event);
2736 * See perf_event_disable()
2738 int perf_event_refresh(struct perf_event *event, int refresh)
2740 struct perf_event_context *ctx;
2743 ctx = perf_event_ctx_lock(event);
2744 ret = _perf_event_refresh(event, refresh);
2745 perf_event_ctx_unlock(event, ctx);
2749 EXPORT_SYMBOL_GPL(perf_event_refresh);
2751 static void ctx_sched_out(struct perf_event_context *ctx,
2752 struct perf_cpu_context *cpuctx,
2753 enum event_type_t event_type)
2755 int is_active = ctx->is_active;
2756 struct perf_event *event;
2758 lockdep_assert_held(&ctx->lock);
2760 if (likely(!ctx->nr_events)) {
2762 * See __perf_remove_from_context().
2764 WARN_ON_ONCE(ctx->is_active);
2766 WARN_ON_ONCE(cpuctx->task_ctx);
2770 ctx->is_active &= ~event_type;
2771 if (!(ctx->is_active & EVENT_ALL))
2775 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2776 if (!ctx->is_active)
2777 cpuctx->task_ctx = NULL;
2781 * Always update time if it was set; not only when it changes.
2782 * Otherwise we can 'forget' to update time for any but the last
2783 * context we sched out. For example:
2785 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2786 * ctx_sched_out(.event_type = EVENT_PINNED)
2788 * would only update time for the pinned events.
2790 if (is_active & EVENT_TIME) {
2791 /* update (and stop) ctx time */
2792 update_context_time(ctx);
2793 update_cgrp_time_from_cpuctx(cpuctx);
2796 is_active ^= ctx->is_active; /* changed bits */
2798 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2801 perf_pmu_disable(ctx->pmu);
2802 if (is_active & EVENT_PINNED) {
2803 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2804 group_sched_out(event, cpuctx, ctx);
2807 if (is_active & EVENT_FLEXIBLE) {
2808 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2809 group_sched_out(event, cpuctx, ctx);
2811 perf_pmu_enable(ctx->pmu);
2815 * Test whether two contexts are equivalent, i.e. whether they have both been
2816 * cloned from the same version of the same context.
2818 * Equivalence is measured using a generation number in the context that is
2819 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2820 * and list_del_event().
2822 static int context_equiv(struct perf_event_context *ctx1,
2823 struct perf_event_context *ctx2)
2825 lockdep_assert_held(&ctx1->lock);
2826 lockdep_assert_held(&ctx2->lock);
2828 /* Pinning disables the swap optimization */
2829 if (ctx1->pin_count || ctx2->pin_count)
2832 /* If ctx1 is the parent of ctx2 */
2833 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2836 /* If ctx2 is the parent of ctx1 */
2837 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2841 * If ctx1 and ctx2 have the same parent; we flatten the parent
2842 * hierarchy, see perf_event_init_context().
2844 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2845 ctx1->parent_gen == ctx2->parent_gen)
2852 static void __perf_event_sync_stat(struct perf_event *event,
2853 struct perf_event *next_event)
2857 if (!event->attr.inherit_stat)
2861 * Update the event value, we cannot use perf_event_read()
2862 * because we're in the middle of a context switch and have IRQs
2863 * disabled, which upsets smp_call_function_single(), however
2864 * we know the event must be on the current CPU, therefore we
2865 * don't need to use it.
2867 switch (event->state) {
2868 case PERF_EVENT_STATE_ACTIVE:
2869 event->pmu->read(event);
2872 case PERF_EVENT_STATE_INACTIVE:
2873 update_event_times(event);
2881 * In order to keep per-task stats reliable we need to flip the event
2882 * values when we flip the contexts.
2884 value = local64_read(&next_event->count);
2885 value = local64_xchg(&event->count, value);
2886 local64_set(&next_event->count, value);
2888 swap(event->total_time_enabled, next_event->total_time_enabled);
2889 swap(event->total_time_running, next_event->total_time_running);
2892 * Since we swizzled the values, update the user visible data too.
2894 perf_event_update_userpage(event);
2895 perf_event_update_userpage(next_event);
2898 static void perf_event_sync_stat(struct perf_event_context *ctx,
2899 struct perf_event_context *next_ctx)
2901 struct perf_event *event, *next_event;
2906 update_context_time(ctx);
2908 event = list_first_entry(&ctx->event_list,
2909 struct perf_event, event_entry);
2911 next_event = list_first_entry(&next_ctx->event_list,
2912 struct perf_event, event_entry);
2914 while (&event->event_entry != &ctx->event_list &&
2915 &next_event->event_entry != &next_ctx->event_list) {
2917 __perf_event_sync_stat(event, next_event);
2919 event = list_next_entry(event, event_entry);
2920 next_event = list_next_entry(next_event, event_entry);
2924 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2925 struct task_struct *next)
2927 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2928 struct perf_event_context *next_ctx;
2929 struct perf_event_context *parent, *next_parent;
2930 struct perf_cpu_context *cpuctx;
2936 cpuctx = __get_cpu_context(ctx);
2937 if (!cpuctx->task_ctx)
2941 next_ctx = next->perf_event_ctxp[ctxn];
2945 parent = rcu_dereference(ctx->parent_ctx);
2946 next_parent = rcu_dereference(next_ctx->parent_ctx);
2948 /* If neither context have a parent context; they cannot be clones. */
2949 if (!parent && !next_parent)
2952 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2954 * Looks like the two contexts are clones, so we might be
2955 * able to optimize the context switch. We lock both
2956 * contexts and check that they are clones under the
2957 * lock (including re-checking that neither has been
2958 * uncloned in the meantime). It doesn't matter which
2959 * order we take the locks because no other cpu could
2960 * be trying to lock both of these tasks.
2962 raw_spin_lock(&ctx->lock);
2963 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2964 if (context_equiv(ctx, next_ctx)) {
2965 WRITE_ONCE(ctx->task, next);
2966 WRITE_ONCE(next_ctx->task, task);
2968 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2971 * RCU_INIT_POINTER here is safe because we've not
2972 * modified the ctx and the above modification of
2973 * ctx->task and ctx->task_ctx_data are immaterial
2974 * since those values are always verified under
2975 * ctx->lock which we're now holding.
2977 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2978 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2982 perf_event_sync_stat(ctx, next_ctx);
2984 raw_spin_unlock(&next_ctx->lock);
2985 raw_spin_unlock(&ctx->lock);
2991 raw_spin_lock(&ctx->lock);
2992 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2993 raw_spin_unlock(&ctx->lock);
2997 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2999 void perf_sched_cb_dec(struct pmu *pmu)
3001 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3003 this_cpu_dec(perf_sched_cb_usages);
3005 if (!--cpuctx->sched_cb_usage)
3006 list_del(&cpuctx->sched_cb_entry);
3010 void perf_sched_cb_inc(struct pmu *pmu)
3012 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3014 if (!cpuctx->sched_cb_usage++)
3015 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3017 this_cpu_inc(perf_sched_cb_usages);
3021 * This function provides the context switch callback to the lower code
3022 * layer. It is invoked ONLY when the context switch callback is enabled.
3024 * This callback is relevant even to per-cpu events; for example multi event
3025 * PEBS requires this to provide PID/TID information. This requires we flush
3026 * all queued PEBS records before we context switch to a new task.
3028 static void perf_pmu_sched_task(struct task_struct *prev,
3029 struct task_struct *next,
3032 struct perf_cpu_context *cpuctx;
3038 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3039 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3041 if (WARN_ON_ONCE(!pmu->sched_task))
3044 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3045 perf_pmu_disable(pmu);
3047 pmu->sched_task(cpuctx->task_ctx, sched_in);
3049 perf_pmu_enable(pmu);
3050 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3054 static void perf_event_switch(struct task_struct *task,
3055 struct task_struct *next_prev, bool sched_in);
3057 #define for_each_task_context_nr(ctxn) \
3058 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3061 * Called from scheduler to remove the events of the current task,
3062 * with interrupts disabled.
3064 * We stop each event and update the event value in event->count.
3066 * This does not protect us against NMI, but disable()
3067 * sets the disabled bit in the control field of event _before_
3068 * accessing the event control register. If a NMI hits, then it will
3069 * not restart the event.
3071 void __perf_event_task_sched_out(struct task_struct *task,
3072 struct task_struct *next)
3076 if (__this_cpu_read(perf_sched_cb_usages))
3077 perf_pmu_sched_task(task, next, false);
3079 if (atomic_read(&nr_switch_events))
3080 perf_event_switch(task, next, false);
3082 for_each_task_context_nr(ctxn)
3083 perf_event_context_sched_out(task, ctxn, next);
3086 * if cgroup events exist on this CPU, then we need
3087 * to check if we have to switch out PMU state.
3088 * cgroup event are system-wide mode only
3090 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3091 perf_cgroup_sched_out(task, next);
3095 * Called with IRQs disabled
3097 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3098 enum event_type_t event_type)
3100 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3104 ctx_pinned_sched_in(struct perf_event_context *ctx,
3105 struct perf_cpu_context *cpuctx)
3107 struct perf_event *event;
3109 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3110 if (event->state <= PERF_EVENT_STATE_OFF)
3112 if (!event_filter_match(event))
3115 /* may need to reset tstamp_enabled */
3116 if (is_cgroup_event(event))
3117 perf_cgroup_mark_enabled(event, ctx);
3119 if (group_can_go_on(event, cpuctx, 1))
3120 group_sched_in(event, cpuctx, ctx);
3123 * If this pinned group hasn't been scheduled,
3124 * put it in error state.
3126 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3127 update_group_times(event);
3128 event->state = PERF_EVENT_STATE_ERROR;
3134 ctx_flexible_sched_in(struct perf_event_context *ctx,
3135 struct perf_cpu_context *cpuctx)
3137 struct perf_event *event;
3140 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3141 /* Ignore events in OFF or ERROR state */
3142 if (event->state <= PERF_EVENT_STATE_OFF)
3145 * Listen to the 'cpu' scheduling filter constraint
3148 if (!event_filter_match(event))
3151 /* may need to reset tstamp_enabled */
3152 if (is_cgroup_event(event))
3153 perf_cgroup_mark_enabled(event, ctx);
3155 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3156 if (group_sched_in(event, cpuctx, ctx))
3163 ctx_sched_in(struct perf_event_context *ctx,
3164 struct perf_cpu_context *cpuctx,
3165 enum event_type_t event_type,
3166 struct task_struct *task)
3168 int is_active = ctx->is_active;
3171 lockdep_assert_held(&ctx->lock);
3173 if (likely(!ctx->nr_events))
3176 ctx->is_active |= (event_type | EVENT_TIME);
3179 cpuctx->task_ctx = ctx;
3181 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3184 is_active ^= ctx->is_active; /* changed bits */
3186 if (is_active & EVENT_TIME) {
3187 /* start ctx time */
3189 ctx->timestamp = now;
3190 perf_cgroup_set_timestamp(task, ctx);
3194 * First go through the list and put on any pinned groups
3195 * in order to give them the best chance of going on.
3197 if (is_active & EVENT_PINNED)
3198 ctx_pinned_sched_in(ctx, cpuctx);
3200 /* Then walk through the lower prio flexible groups */
3201 if (is_active & EVENT_FLEXIBLE)
3202 ctx_flexible_sched_in(ctx, cpuctx);
3205 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3206 enum event_type_t event_type,
3207 struct task_struct *task)
3209 struct perf_event_context *ctx = &cpuctx->ctx;
3211 ctx_sched_in(ctx, cpuctx, event_type, task);
3214 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3215 struct task_struct *task)
3217 struct perf_cpu_context *cpuctx;
3219 cpuctx = __get_cpu_context(ctx);
3220 if (cpuctx->task_ctx == ctx)
3223 perf_ctx_lock(cpuctx, ctx);
3225 * We must check ctx->nr_events while holding ctx->lock, such
3226 * that we serialize against perf_install_in_context().
3228 if (!ctx->nr_events)
3231 perf_pmu_disable(ctx->pmu);
3233 * We want to keep the following priority order:
3234 * cpu pinned (that don't need to move), task pinned,
3235 * cpu flexible, task flexible.
3237 * However, if task's ctx is not carrying any pinned
3238 * events, no need to flip the cpuctx's events around.
3240 if (!list_empty(&ctx->pinned_groups))
3241 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3242 perf_event_sched_in(cpuctx, ctx, task);
3243 perf_pmu_enable(ctx->pmu);
3246 perf_ctx_unlock(cpuctx, ctx);
3250 * Called from scheduler to add the events of the current task
3251 * with interrupts disabled.
3253 * We restore the event value and then enable it.
3255 * This does not protect us against NMI, but enable()
3256 * sets the enabled bit in the control field of event _before_
3257 * accessing the event control register. If a NMI hits, then it will
3258 * keep the event running.
3260 void __perf_event_task_sched_in(struct task_struct *prev,
3261 struct task_struct *task)
3263 struct perf_event_context *ctx;
3267 * If cgroup events exist on this CPU, then we need to check if we have
3268 * to switch in PMU state; cgroup event are system-wide mode only.
3270 * Since cgroup events are CPU events, we must schedule these in before
3271 * we schedule in the task events.
3273 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3274 perf_cgroup_sched_in(prev, task);
3276 for_each_task_context_nr(ctxn) {
3277 ctx = task->perf_event_ctxp[ctxn];
3281 perf_event_context_sched_in(ctx, task);
3284 if (atomic_read(&nr_switch_events))
3285 perf_event_switch(task, prev, true);
3287 if (__this_cpu_read(perf_sched_cb_usages))
3288 perf_pmu_sched_task(prev, task, true);
3291 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3293 u64 frequency = event->attr.sample_freq;
3294 u64 sec = NSEC_PER_SEC;
3295 u64 divisor, dividend;
3297 int count_fls, nsec_fls, frequency_fls, sec_fls;
3299 count_fls = fls64(count);
3300 nsec_fls = fls64(nsec);
3301 frequency_fls = fls64(frequency);
3305 * We got @count in @nsec, with a target of sample_freq HZ
3306 * the target period becomes:
3309 * period = -------------------
3310 * @nsec * sample_freq
3315 * Reduce accuracy by one bit such that @a and @b converge
3316 * to a similar magnitude.
3318 #define REDUCE_FLS(a, b) \
3320 if (a##_fls > b##_fls) { \
3330 * Reduce accuracy until either term fits in a u64, then proceed with
3331 * the other, so that finally we can do a u64/u64 division.
3333 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3334 REDUCE_FLS(nsec, frequency);
3335 REDUCE_FLS(sec, count);
3338 if (count_fls + sec_fls > 64) {
3339 divisor = nsec * frequency;
3341 while (count_fls + sec_fls > 64) {
3342 REDUCE_FLS(count, sec);
3346 dividend = count * sec;
3348 dividend = count * sec;
3350 while (nsec_fls + frequency_fls > 64) {
3351 REDUCE_FLS(nsec, frequency);
3355 divisor = nsec * frequency;
3361 return div64_u64(dividend, divisor);
3364 static DEFINE_PER_CPU(int, perf_throttled_count);
3365 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3367 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3369 struct hw_perf_event *hwc = &event->hw;
3370 s64 period, sample_period;
3373 period = perf_calculate_period(event, nsec, count);
3375 delta = (s64)(period - hwc->sample_period);
3376 delta = (delta + 7) / 8; /* low pass filter */
3378 sample_period = hwc->sample_period + delta;
3383 hwc->sample_period = sample_period;
3385 if (local64_read(&hwc->period_left) > 8*sample_period) {
3387 event->pmu->stop(event, PERF_EF_UPDATE);
3389 local64_set(&hwc->period_left, 0);
3392 event->pmu->start(event, PERF_EF_RELOAD);
3397 * combine freq adjustment with unthrottling to avoid two passes over the
3398 * events. At the same time, make sure, having freq events does not change
3399 * the rate of unthrottling as that would introduce bias.
3401 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3404 struct perf_event *event;
3405 struct hw_perf_event *hwc;
3406 u64 now, period = TICK_NSEC;
3410 * only need to iterate over all events iff:
3411 * - context have events in frequency mode (needs freq adjust)
3412 * - there are events to unthrottle on this cpu
3414 if (!(ctx->nr_freq || needs_unthr))
3417 raw_spin_lock(&ctx->lock);
3418 perf_pmu_disable(ctx->pmu);
3420 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3421 if (event->state != PERF_EVENT_STATE_ACTIVE)
3424 if (!event_filter_match(event))
3427 perf_pmu_disable(event->pmu);
3431 if (hwc->interrupts == MAX_INTERRUPTS) {
3432 hwc->interrupts = 0;
3433 perf_log_throttle(event, 1);
3434 event->pmu->start(event, 0);
3437 if (!event->attr.freq || !event->attr.sample_freq)
3441 * stop the event and update event->count
3443 event->pmu->stop(event, PERF_EF_UPDATE);
3445 now = local64_read(&event->count);
3446 delta = now - hwc->freq_count_stamp;
3447 hwc->freq_count_stamp = now;
3451 * reload only if value has changed
3452 * we have stopped the event so tell that
3453 * to perf_adjust_period() to avoid stopping it
3457 perf_adjust_period(event, period, delta, false);
3459 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3461 perf_pmu_enable(event->pmu);
3464 perf_pmu_enable(ctx->pmu);
3465 raw_spin_unlock(&ctx->lock);
3469 * Round-robin a context's events:
3471 static void rotate_ctx(struct perf_event_context *ctx)
3474 * Rotate the first entry last of non-pinned groups. Rotation might be
3475 * disabled by the inheritance code.
3477 if (!ctx->rotate_disable)
3478 list_rotate_left(&ctx->flexible_groups);
3481 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3483 struct perf_event_context *ctx = NULL;
3486 if (cpuctx->ctx.nr_events) {
3487 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3491 ctx = cpuctx->task_ctx;
3492 if (ctx && ctx->nr_events) {
3493 if (ctx->nr_events != ctx->nr_active)
3500 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3501 perf_pmu_disable(cpuctx->ctx.pmu);
3503 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3505 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3507 rotate_ctx(&cpuctx->ctx);
3511 perf_event_sched_in(cpuctx, ctx, current);
3513 perf_pmu_enable(cpuctx->ctx.pmu);
3514 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3520 void perf_event_task_tick(void)
3522 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3523 struct perf_event_context *ctx, *tmp;
3526 WARN_ON(!irqs_disabled());
3528 __this_cpu_inc(perf_throttled_seq);
3529 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3530 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3532 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3533 perf_adjust_freq_unthr_context(ctx, throttled);
3536 static int event_enable_on_exec(struct perf_event *event,
3537 struct perf_event_context *ctx)
3539 if (!event->attr.enable_on_exec)
3542 event->attr.enable_on_exec = 0;
3543 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3546 __perf_event_mark_enabled(event);
3552 * Enable all of a task's events that have been marked enable-on-exec.
3553 * This expects task == current.
3555 static void perf_event_enable_on_exec(int ctxn)
3557 struct perf_event_context *ctx, *clone_ctx = NULL;
3558 enum event_type_t event_type = 0;
3559 struct perf_cpu_context *cpuctx;
3560 struct perf_event *event;
3561 unsigned long flags;
3564 local_irq_save(flags);
3565 ctx = current->perf_event_ctxp[ctxn];
3566 if (!ctx || !ctx->nr_events)
3569 cpuctx = __get_cpu_context(ctx);
3570 perf_ctx_lock(cpuctx, ctx);
3571 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3572 list_for_each_entry(event, &ctx->event_list, event_entry) {
3573 enabled |= event_enable_on_exec(event, ctx);
3574 event_type |= get_event_type(event);
3578 * Unclone and reschedule this context if we enabled any event.
3581 clone_ctx = unclone_ctx(ctx);
3582 ctx_resched(cpuctx, ctx, event_type);
3584 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3586 perf_ctx_unlock(cpuctx, ctx);
3589 local_irq_restore(flags);
3595 struct perf_read_data {
3596 struct perf_event *event;
3601 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3603 u16 local_pkg, event_pkg;
3605 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3606 int local_cpu = smp_processor_id();
3608 event_pkg = topology_physical_package_id(event_cpu);
3609 local_pkg = topology_physical_package_id(local_cpu);
3611 if (event_pkg == local_pkg)
3619 * Cross CPU call to read the hardware event
3621 static void __perf_event_read(void *info)
3623 struct perf_read_data *data = info;
3624 struct perf_event *sub, *event = data->event;
3625 struct perf_event_context *ctx = event->ctx;
3626 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3627 struct pmu *pmu = event->pmu;
3630 * If this is a task context, we need to check whether it is
3631 * the current task context of this cpu. If not it has been
3632 * scheduled out before the smp call arrived. In that case
3633 * event->count would have been updated to a recent sample
3634 * when the event was scheduled out.
3636 if (ctx->task && cpuctx->task_ctx != ctx)
3639 raw_spin_lock(&ctx->lock);
3640 if (ctx->is_active) {
3641 update_context_time(ctx);
3642 update_cgrp_time_from_event(event);
3645 update_event_times(event);
3646 if (event->state != PERF_EVENT_STATE_ACTIVE)
3655 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3659 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3660 update_event_times(sub);
3661 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3663 * Use sibling's PMU rather than @event's since
3664 * sibling could be on different (eg: software) PMU.
3666 sub->pmu->read(sub);
3670 data->ret = pmu->commit_txn(pmu);
3673 raw_spin_unlock(&ctx->lock);
3676 static inline u64 perf_event_count(struct perf_event *event)
3678 return local64_read(&event->count) + atomic64_read(&event->child_count);
3682 * NMI-safe method to read a local event, that is an event that
3684 * - either for the current task, or for this CPU
3685 * - does not have inherit set, for inherited task events
3686 * will not be local and we cannot read them atomically
3687 * - must not have a pmu::count method
3689 int perf_event_read_local(struct perf_event *event, u64 *value)
3691 unsigned long flags;
3695 * Disabling interrupts avoids all counter scheduling (context
3696 * switches, timer based rotation and IPIs).
3698 local_irq_save(flags);
3701 * It must not be an event with inherit set, we cannot read
3702 * all child counters from atomic context.
3704 if (event->attr.inherit) {
3709 /* If this is a per-task event, it must be for current */
3710 if ((event->attach_state & PERF_ATTACH_TASK) &&
3711 event->hw.target != current) {
3716 /* If this is a per-CPU event, it must be for this CPU */
3717 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3718 event->cpu != smp_processor_id()) {
3724 * If the event is currently on this CPU, its either a per-task event,
3725 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3728 if (event->oncpu == smp_processor_id())
3729 event->pmu->read(event);
3731 *value = local64_read(&event->count);
3733 local_irq_restore(flags);
3738 static int perf_event_read(struct perf_event *event, bool group)
3740 int event_cpu, ret = 0;
3743 * If event is enabled and currently active on a CPU, update the
3744 * value in the event structure:
3746 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3747 struct perf_read_data data = {
3753 event_cpu = READ_ONCE(event->oncpu);
3754 if ((unsigned)event_cpu >= nr_cpu_ids)
3758 event_cpu = __perf_event_read_cpu(event, event_cpu);
3761 * Purposely ignore the smp_call_function_single() return
3764 * If event_cpu isn't a valid CPU it means the event got
3765 * scheduled out and that will have updated the event count.
3767 * Therefore, either way, we'll have an up-to-date event count
3770 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3773 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3774 struct perf_event_context *ctx = event->ctx;
3775 unsigned long flags;
3777 raw_spin_lock_irqsave(&ctx->lock, flags);
3779 * may read while context is not active
3780 * (e.g., thread is blocked), in that case
3781 * we cannot update context time
3783 if (ctx->is_active) {
3784 update_context_time(ctx);
3785 update_cgrp_time_from_event(event);
3788 update_group_times(event);
3790 update_event_times(event);
3791 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3798 * Initialize the perf_event context in a task_struct:
3800 static void __perf_event_init_context(struct perf_event_context *ctx)
3802 raw_spin_lock_init(&ctx->lock);
3803 mutex_init(&ctx->mutex);
3804 INIT_LIST_HEAD(&ctx->active_ctx_list);
3805 INIT_LIST_HEAD(&ctx->pinned_groups);
3806 INIT_LIST_HEAD(&ctx->flexible_groups);
3807 INIT_LIST_HEAD(&ctx->event_list);
3808 atomic_set(&ctx->refcount, 1);
3811 static struct perf_event_context *
3812 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3814 struct perf_event_context *ctx;
3816 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3820 __perf_event_init_context(ctx);
3823 get_task_struct(task);
3830 static struct task_struct *
3831 find_lively_task_by_vpid(pid_t vpid)
3833 struct task_struct *task;
3839 task = find_task_by_vpid(vpid);
3841 get_task_struct(task);
3845 return ERR_PTR(-ESRCH);
3851 * Returns a matching context with refcount and pincount.
3853 static struct perf_event_context *
3854 find_get_context(struct pmu *pmu, struct task_struct *task,
3855 struct perf_event *event)
3857 struct perf_event_context *ctx, *clone_ctx = NULL;
3858 struct perf_cpu_context *cpuctx;
3859 void *task_ctx_data = NULL;
3860 unsigned long flags;
3862 int cpu = event->cpu;
3865 /* Must be root to operate on a CPU event: */
3866 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3867 return ERR_PTR(-EACCES);
3869 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3878 ctxn = pmu->task_ctx_nr;
3882 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3883 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3884 if (!task_ctx_data) {
3891 ctx = perf_lock_task_context(task, ctxn, &flags);
3893 clone_ctx = unclone_ctx(ctx);
3896 if (task_ctx_data && !ctx->task_ctx_data) {
3897 ctx->task_ctx_data = task_ctx_data;
3898 task_ctx_data = NULL;
3900 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3905 ctx = alloc_perf_context(pmu, task);
3910 if (task_ctx_data) {
3911 ctx->task_ctx_data = task_ctx_data;
3912 task_ctx_data = NULL;
3916 mutex_lock(&task->perf_event_mutex);
3918 * If it has already passed perf_event_exit_task().
3919 * we must see PF_EXITING, it takes this mutex too.
3921 if (task->flags & PF_EXITING)
3923 else if (task->perf_event_ctxp[ctxn])
3928 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3930 mutex_unlock(&task->perf_event_mutex);
3932 if (unlikely(err)) {
3941 kfree(task_ctx_data);
3945 kfree(task_ctx_data);
3946 return ERR_PTR(err);
3949 static void perf_event_free_filter(struct perf_event *event);
3950 static void perf_event_free_bpf_prog(struct perf_event *event);
3952 static void free_event_rcu(struct rcu_head *head)
3954 struct perf_event *event;
3956 event = container_of(head, struct perf_event, rcu_head);
3958 put_pid_ns(event->ns);
3959 perf_event_free_filter(event);
3963 static void ring_buffer_attach(struct perf_event *event,
3964 struct ring_buffer *rb);
3966 static void detach_sb_event(struct perf_event *event)
3968 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3970 raw_spin_lock(&pel->lock);
3971 list_del_rcu(&event->sb_list);
3972 raw_spin_unlock(&pel->lock);
3975 static bool is_sb_event(struct perf_event *event)
3977 struct perf_event_attr *attr = &event->attr;
3982 if (event->attach_state & PERF_ATTACH_TASK)
3985 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3986 attr->comm || attr->comm_exec ||
3988 attr->context_switch)
3993 static void unaccount_pmu_sb_event(struct perf_event *event)
3995 if (is_sb_event(event))
3996 detach_sb_event(event);
3999 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4004 if (is_cgroup_event(event))
4005 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4008 #ifdef CONFIG_NO_HZ_FULL
4009 static DEFINE_SPINLOCK(nr_freq_lock);
4012 static void unaccount_freq_event_nohz(void)
4014 #ifdef CONFIG_NO_HZ_FULL
4015 spin_lock(&nr_freq_lock);
4016 if (atomic_dec_and_test(&nr_freq_events))
4017 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4018 spin_unlock(&nr_freq_lock);
4022 static void unaccount_freq_event(void)
4024 if (tick_nohz_full_enabled())
4025 unaccount_freq_event_nohz();
4027 atomic_dec(&nr_freq_events);
4030 static void unaccount_event(struct perf_event *event)
4037 if (event->attach_state & PERF_ATTACH_TASK)
4039 if (event->attr.mmap || event->attr.mmap_data)
4040 atomic_dec(&nr_mmap_events);
4041 if (event->attr.comm)
4042 atomic_dec(&nr_comm_events);
4043 if (event->attr.namespaces)
4044 atomic_dec(&nr_namespaces_events);
4045 if (event->attr.task)
4046 atomic_dec(&nr_task_events);
4047 if (event->attr.freq)
4048 unaccount_freq_event();
4049 if (event->attr.context_switch) {
4051 atomic_dec(&nr_switch_events);
4053 if (is_cgroup_event(event))
4055 if (has_branch_stack(event))
4059 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4060 schedule_delayed_work(&perf_sched_work, HZ);
4063 unaccount_event_cpu(event, event->cpu);
4065 unaccount_pmu_sb_event(event);
4068 static void perf_sched_delayed(struct work_struct *work)
4070 mutex_lock(&perf_sched_mutex);
4071 if (atomic_dec_and_test(&perf_sched_count))
4072 static_branch_disable(&perf_sched_events);
4073 mutex_unlock(&perf_sched_mutex);
4077 * The following implement mutual exclusion of events on "exclusive" pmus
4078 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4079 * at a time, so we disallow creating events that might conflict, namely:
4081 * 1) cpu-wide events in the presence of per-task events,
4082 * 2) per-task events in the presence of cpu-wide events,
4083 * 3) two matching events on the same context.
4085 * The former two cases are handled in the allocation path (perf_event_alloc(),
4086 * _free_event()), the latter -- before the first perf_install_in_context().
4088 static int exclusive_event_init(struct perf_event *event)
4090 struct pmu *pmu = event->pmu;
4092 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4096 * Prevent co-existence of per-task and cpu-wide events on the
4097 * same exclusive pmu.
4099 * Negative pmu::exclusive_cnt means there are cpu-wide
4100 * events on this "exclusive" pmu, positive means there are
4103 * Since this is called in perf_event_alloc() path, event::ctx
4104 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4105 * to mean "per-task event", because unlike other attach states it
4106 * never gets cleared.
4108 if (event->attach_state & PERF_ATTACH_TASK) {
4109 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4112 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4119 static void exclusive_event_destroy(struct perf_event *event)
4121 struct pmu *pmu = event->pmu;
4123 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4126 /* see comment in exclusive_event_init() */
4127 if (event->attach_state & PERF_ATTACH_TASK)
4128 atomic_dec(&pmu->exclusive_cnt);
4130 atomic_inc(&pmu->exclusive_cnt);
4133 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4135 if ((e1->pmu == e2->pmu) &&
4136 (e1->cpu == e2->cpu ||
4143 /* Called under the same ctx::mutex as perf_install_in_context() */
4144 static bool exclusive_event_installable(struct perf_event *event,
4145 struct perf_event_context *ctx)
4147 struct perf_event *iter_event;
4148 struct pmu *pmu = event->pmu;
4150 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4153 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4154 if (exclusive_event_match(iter_event, event))
4161 static void perf_addr_filters_splice(struct perf_event *event,
4162 struct list_head *head);
4164 static void _free_event(struct perf_event *event)
4166 irq_work_sync(&event->pending);
4168 unaccount_event(event);
4172 * Can happen when we close an event with re-directed output.
4174 * Since we have a 0 refcount, perf_mmap_close() will skip
4175 * over us; possibly making our ring_buffer_put() the last.
4177 mutex_lock(&event->mmap_mutex);
4178 ring_buffer_attach(event, NULL);
4179 mutex_unlock(&event->mmap_mutex);
4182 if (is_cgroup_event(event))
4183 perf_detach_cgroup(event);
4185 if (!event->parent) {
4186 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4187 put_callchain_buffers();
4190 perf_event_free_bpf_prog(event);
4191 perf_addr_filters_splice(event, NULL);
4192 kfree(event->addr_filters_offs);
4195 event->destroy(event);
4198 put_ctx(event->ctx);
4200 exclusive_event_destroy(event);
4201 module_put(event->pmu->module);
4203 call_rcu(&event->rcu_head, free_event_rcu);
4207 * Used to free events which have a known refcount of 1, such as in error paths
4208 * where the event isn't exposed yet and inherited events.
4210 static void free_event(struct perf_event *event)
4212 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4213 "unexpected event refcount: %ld; ptr=%p\n",
4214 atomic_long_read(&event->refcount), event)) {
4215 /* leak to avoid use-after-free */
4223 * Remove user event from the owner task.
4225 static void perf_remove_from_owner(struct perf_event *event)
4227 struct task_struct *owner;
4231 * Matches the smp_store_release() in perf_event_exit_task(). If we
4232 * observe !owner it means the list deletion is complete and we can
4233 * indeed free this event, otherwise we need to serialize on
4234 * owner->perf_event_mutex.
4236 owner = READ_ONCE(event->owner);
4239 * Since delayed_put_task_struct() also drops the last
4240 * task reference we can safely take a new reference
4241 * while holding the rcu_read_lock().
4243 get_task_struct(owner);
4249 * If we're here through perf_event_exit_task() we're already
4250 * holding ctx->mutex which would be an inversion wrt. the
4251 * normal lock order.
4253 * However we can safely take this lock because its the child
4256 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4259 * We have to re-check the event->owner field, if it is cleared
4260 * we raced with perf_event_exit_task(), acquiring the mutex
4261 * ensured they're done, and we can proceed with freeing the
4265 list_del_init(&event->owner_entry);
4266 smp_store_release(&event->owner, NULL);
4268 mutex_unlock(&owner->perf_event_mutex);
4269 put_task_struct(owner);
4273 static void put_event(struct perf_event *event)
4275 if (!atomic_long_dec_and_test(&event->refcount))
4282 * Kill an event dead; while event:refcount will preserve the event
4283 * object, it will not preserve its functionality. Once the last 'user'
4284 * gives up the object, we'll destroy the thing.
4286 int perf_event_release_kernel(struct perf_event *event)
4288 struct perf_event_context *ctx = event->ctx;
4289 struct perf_event *child, *tmp;
4292 * If we got here through err_file: fput(event_file); we will not have
4293 * attached to a context yet.
4296 WARN_ON_ONCE(event->attach_state &
4297 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4301 if (!is_kernel_event(event))
4302 perf_remove_from_owner(event);
4304 ctx = perf_event_ctx_lock(event);
4305 WARN_ON_ONCE(ctx->parent_ctx);
4306 perf_remove_from_context(event, DETACH_GROUP);
4308 raw_spin_lock_irq(&ctx->lock);
4310 * Mark this event as STATE_DEAD, there is no external reference to it
4313 * Anybody acquiring event->child_mutex after the below loop _must_
4314 * also see this, most importantly inherit_event() which will avoid
4315 * placing more children on the list.
4317 * Thus this guarantees that we will in fact observe and kill _ALL_
4320 event->state = PERF_EVENT_STATE_DEAD;
4321 raw_spin_unlock_irq(&ctx->lock);
4323 perf_event_ctx_unlock(event, ctx);
4326 mutex_lock(&event->child_mutex);
4327 list_for_each_entry(child, &event->child_list, child_list) {
4330 * Cannot change, child events are not migrated, see the
4331 * comment with perf_event_ctx_lock_nested().
4333 ctx = READ_ONCE(child->ctx);
4335 * Since child_mutex nests inside ctx::mutex, we must jump
4336 * through hoops. We start by grabbing a reference on the ctx.
4338 * Since the event cannot get freed while we hold the
4339 * child_mutex, the context must also exist and have a !0
4345 * Now that we have a ctx ref, we can drop child_mutex, and
4346 * acquire ctx::mutex without fear of it going away. Then we
4347 * can re-acquire child_mutex.
4349 mutex_unlock(&event->child_mutex);
4350 mutex_lock(&ctx->mutex);
4351 mutex_lock(&event->child_mutex);
4354 * Now that we hold ctx::mutex and child_mutex, revalidate our
4355 * state, if child is still the first entry, it didn't get freed
4356 * and we can continue doing so.
4358 tmp = list_first_entry_or_null(&event->child_list,
4359 struct perf_event, child_list);
4361 perf_remove_from_context(child, DETACH_GROUP);
4362 list_del(&child->child_list);
4365 * This matches the refcount bump in inherit_event();
4366 * this can't be the last reference.
4371 mutex_unlock(&event->child_mutex);
4372 mutex_unlock(&ctx->mutex);
4376 mutex_unlock(&event->child_mutex);
4379 put_event(event); /* Must be the 'last' reference */
4382 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4385 * Called when the last reference to the file is gone.
4387 static int perf_release(struct inode *inode, struct file *file)
4389 perf_event_release_kernel(file->private_data);
4393 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4395 struct perf_event *child;
4401 mutex_lock(&event->child_mutex);
4403 (void)perf_event_read(event, false);
4404 total += perf_event_count(event);
4406 *enabled += event->total_time_enabled +
4407 atomic64_read(&event->child_total_time_enabled);
4408 *running += event->total_time_running +
4409 atomic64_read(&event->child_total_time_running);
4411 list_for_each_entry(child, &event->child_list, child_list) {
4412 (void)perf_event_read(child, false);
4413 total += perf_event_count(child);
4414 *enabled += child->total_time_enabled;
4415 *running += child->total_time_running;
4417 mutex_unlock(&event->child_mutex);
4421 EXPORT_SYMBOL_GPL(perf_event_read_value);
4423 static int __perf_read_group_add(struct perf_event *leader,
4424 u64 read_format, u64 *values)
4426 struct perf_event_context *ctx = leader->ctx;
4427 struct perf_event *sub;
4428 unsigned long flags;
4429 int n = 1; /* skip @nr */
4432 ret = perf_event_read(leader, true);
4436 raw_spin_lock_irqsave(&ctx->lock, flags);
4439 * Since we co-schedule groups, {enabled,running} times of siblings
4440 * will be identical to those of the leader, so we only publish one
4443 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4444 values[n++] += leader->total_time_enabled +
4445 atomic64_read(&leader->child_total_time_enabled);
4448 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4449 values[n++] += leader->total_time_running +
4450 atomic64_read(&leader->child_total_time_running);
4454 * Write {count,id} tuples for every sibling.
4456 values[n++] += perf_event_count(leader);
4457 if (read_format & PERF_FORMAT_ID)
4458 values[n++] = primary_event_id(leader);
4460 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4461 values[n++] += perf_event_count(sub);
4462 if (read_format & PERF_FORMAT_ID)
4463 values[n++] = primary_event_id(sub);
4466 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4470 static int perf_read_group(struct perf_event *event,
4471 u64 read_format, char __user *buf)
4473 struct perf_event *leader = event->group_leader, *child;
4474 struct perf_event_context *ctx = leader->ctx;
4478 lockdep_assert_held(&ctx->mutex);
4480 values = kzalloc(event->read_size, GFP_KERNEL);
4484 values[0] = 1 + leader->nr_siblings;
4487 * By locking the child_mutex of the leader we effectively
4488 * lock the child list of all siblings.. XXX explain how.
4490 mutex_lock(&leader->child_mutex);
4492 ret = __perf_read_group_add(leader, read_format, values);
4496 list_for_each_entry(child, &leader->child_list, child_list) {
4497 ret = __perf_read_group_add(child, read_format, values);
4502 mutex_unlock(&leader->child_mutex);
4504 ret = event->read_size;
4505 if (copy_to_user(buf, values, event->read_size))
4510 mutex_unlock(&leader->child_mutex);
4516 static int perf_read_one(struct perf_event *event,
4517 u64 read_format, char __user *buf)
4519 u64 enabled, running;
4523 values[n++] = perf_event_read_value(event, &enabled, &running);
4524 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4525 values[n++] = enabled;
4526 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4527 values[n++] = running;
4528 if (read_format & PERF_FORMAT_ID)
4529 values[n++] = primary_event_id(event);
4531 if (copy_to_user(buf, values, n * sizeof(u64)))
4534 return n * sizeof(u64);
4537 static bool is_event_hup(struct perf_event *event)
4541 if (event->state > PERF_EVENT_STATE_EXIT)
4544 mutex_lock(&event->child_mutex);
4545 no_children = list_empty(&event->child_list);
4546 mutex_unlock(&event->child_mutex);
4551 * Read the performance event - simple non blocking version for now
4554 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4556 u64 read_format = event->attr.read_format;
4560 * Return end-of-file for a read on a event that is in
4561 * error state (i.e. because it was pinned but it couldn't be
4562 * scheduled on to the CPU at some point).
4564 if (event->state == PERF_EVENT_STATE_ERROR)
4567 if (count < event->read_size)
4570 WARN_ON_ONCE(event->ctx->parent_ctx);
4571 if (read_format & PERF_FORMAT_GROUP)
4572 ret = perf_read_group(event, read_format, buf);
4574 ret = perf_read_one(event, read_format, buf);
4580 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4582 struct perf_event *event = file->private_data;
4583 struct perf_event_context *ctx;
4586 ctx = perf_event_ctx_lock(event);
4587 ret = __perf_read(event, buf, count);
4588 perf_event_ctx_unlock(event, ctx);
4593 static unsigned int perf_poll(struct file *file, poll_table *wait)
4595 struct perf_event *event = file->private_data;
4596 struct ring_buffer *rb;
4597 unsigned int events = POLLHUP;
4599 poll_wait(file, &event->waitq, wait);
4601 if (is_event_hup(event))
4605 * Pin the event->rb by taking event->mmap_mutex; otherwise
4606 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4608 mutex_lock(&event->mmap_mutex);
4611 events = atomic_xchg(&rb->poll, 0);
4612 mutex_unlock(&event->mmap_mutex);
4616 static void _perf_event_reset(struct perf_event *event)
4618 (void)perf_event_read(event, false);
4619 local64_set(&event->count, 0);
4620 perf_event_update_userpage(event);
4624 * Holding the top-level event's child_mutex means that any
4625 * descendant process that has inherited this event will block
4626 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4627 * task existence requirements of perf_event_enable/disable.
4629 static void perf_event_for_each_child(struct perf_event *event,
4630 void (*func)(struct perf_event *))
4632 struct perf_event *child;
4634 WARN_ON_ONCE(event->ctx->parent_ctx);
4636 mutex_lock(&event->child_mutex);
4638 list_for_each_entry(child, &event->child_list, child_list)
4640 mutex_unlock(&event->child_mutex);
4643 static void perf_event_for_each(struct perf_event *event,
4644 void (*func)(struct perf_event *))
4646 struct perf_event_context *ctx = event->ctx;
4647 struct perf_event *sibling;
4649 lockdep_assert_held(&ctx->mutex);
4651 event = event->group_leader;
4653 perf_event_for_each_child(event, func);
4654 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4655 perf_event_for_each_child(sibling, func);
4658 static void __perf_event_period(struct perf_event *event,
4659 struct perf_cpu_context *cpuctx,
4660 struct perf_event_context *ctx,
4663 u64 value = *((u64 *)info);
4666 if (event->attr.freq) {
4667 event->attr.sample_freq = value;
4669 event->attr.sample_period = value;
4670 event->hw.sample_period = value;
4673 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4675 perf_pmu_disable(ctx->pmu);
4677 * We could be throttled; unthrottle now to avoid the tick
4678 * trying to unthrottle while we already re-started the event.
4680 if (event->hw.interrupts == MAX_INTERRUPTS) {
4681 event->hw.interrupts = 0;
4682 perf_log_throttle(event, 1);
4684 event->pmu->stop(event, PERF_EF_UPDATE);
4687 local64_set(&event->hw.period_left, 0);
4690 event->pmu->start(event, PERF_EF_RELOAD);
4691 perf_pmu_enable(ctx->pmu);
4695 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4699 if (!is_sampling_event(event))
4702 if (copy_from_user(&value, arg, sizeof(value)))
4708 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4711 event_function_call(event, __perf_event_period, &value);
4716 static const struct file_operations perf_fops;
4718 static inline int perf_fget_light(int fd, struct fd *p)
4720 struct fd f = fdget(fd);
4724 if (f.file->f_op != &perf_fops) {
4732 static int perf_event_set_output(struct perf_event *event,
4733 struct perf_event *output_event);
4734 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4735 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4737 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4739 void (*func)(struct perf_event *);
4743 case PERF_EVENT_IOC_ENABLE:
4744 func = _perf_event_enable;
4746 case PERF_EVENT_IOC_DISABLE:
4747 func = _perf_event_disable;
4749 case PERF_EVENT_IOC_RESET:
4750 func = _perf_event_reset;
4753 case PERF_EVENT_IOC_REFRESH:
4754 return _perf_event_refresh(event, arg);
4756 case PERF_EVENT_IOC_PERIOD:
4757 return perf_event_period(event, (u64 __user *)arg);
4759 case PERF_EVENT_IOC_ID:
4761 u64 id = primary_event_id(event);
4763 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4768 case PERF_EVENT_IOC_SET_OUTPUT:
4772 struct perf_event *output_event;
4774 ret = perf_fget_light(arg, &output);
4777 output_event = output.file->private_data;
4778 ret = perf_event_set_output(event, output_event);
4781 ret = perf_event_set_output(event, NULL);
4786 case PERF_EVENT_IOC_SET_FILTER:
4787 return perf_event_set_filter(event, (void __user *)arg);
4789 case PERF_EVENT_IOC_SET_BPF:
4790 return perf_event_set_bpf_prog(event, arg);
4792 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4793 struct ring_buffer *rb;
4796 rb = rcu_dereference(event->rb);
4797 if (!rb || !rb->nr_pages) {
4801 rb_toggle_paused(rb, !!arg);
4809 if (flags & PERF_IOC_FLAG_GROUP)
4810 perf_event_for_each(event, func);
4812 perf_event_for_each_child(event, func);
4817 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4819 struct perf_event *event = file->private_data;
4820 struct perf_event_context *ctx;
4823 ctx = perf_event_ctx_lock(event);
4824 ret = _perf_ioctl(event, cmd, arg);
4825 perf_event_ctx_unlock(event, ctx);
4830 #ifdef CONFIG_COMPAT
4831 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4834 switch (_IOC_NR(cmd)) {
4835 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4836 case _IOC_NR(PERF_EVENT_IOC_ID):
4837 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4838 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4839 cmd &= ~IOCSIZE_MASK;
4840 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4844 return perf_ioctl(file, cmd, arg);
4847 # define perf_compat_ioctl NULL
4850 int perf_event_task_enable(void)
4852 struct perf_event_context *ctx;
4853 struct perf_event *event;
4855 mutex_lock(¤t->perf_event_mutex);
4856 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4857 ctx = perf_event_ctx_lock(event);
4858 perf_event_for_each_child(event, _perf_event_enable);
4859 perf_event_ctx_unlock(event, ctx);
4861 mutex_unlock(¤t->perf_event_mutex);
4866 int perf_event_task_disable(void)
4868 struct perf_event_context *ctx;
4869 struct perf_event *event;
4871 mutex_lock(¤t->perf_event_mutex);
4872 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4873 ctx = perf_event_ctx_lock(event);
4874 perf_event_for_each_child(event, _perf_event_disable);
4875 perf_event_ctx_unlock(event, ctx);
4877 mutex_unlock(¤t->perf_event_mutex);
4882 static int perf_event_index(struct perf_event *event)
4884 if (event->hw.state & PERF_HES_STOPPED)
4887 if (event->state != PERF_EVENT_STATE_ACTIVE)
4890 return event->pmu->event_idx(event);
4893 static void calc_timer_values(struct perf_event *event,
4900 *now = perf_clock();
4901 ctx_time = event->shadow_ctx_time + *now;
4902 *enabled = ctx_time - event->tstamp_enabled;
4903 *running = ctx_time - event->tstamp_running;
4906 static void perf_event_init_userpage(struct perf_event *event)
4908 struct perf_event_mmap_page *userpg;
4909 struct ring_buffer *rb;
4912 rb = rcu_dereference(event->rb);
4916 userpg = rb->user_page;
4918 /* Allow new userspace to detect that bit 0 is deprecated */
4919 userpg->cap_bit0_is_deprecated = 1;
4920 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4921 userpg->data_offset = PAGE_SIZE;
4922 userpg->data_size = perf_data_size(rb);
4928 void __weak arch_perf_update_userpage(
4929 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4934 * Callers need to ensure there can be no nesting of this function, otherwise
4935 * the seqlock logic goes bad. We can not serialize this because the arch
4936 * code calls this from NMI context.
4938 void perf_event_update_userpage(struct perf_event *event)
4940 struct perf_event_mmap_page *userpg;
4941 struct ring_buffer *rb;
4942 u64 enabled, running, now;
4945 rb = rcu_dereference(event->rb);
4950 * compute total_time_enabled, total_time_running
4951 * based on snapshot values taken when the event
4952 * was last scheduled in.
4954 * we cannot simply called update_context_time()
4955 * because of locking issue as we can be called in
4958 calc_timer_values(event, &now, &enabled, &running);
4960 userpg = rb->user_page;
4962 * Disable preemption so as to not let the corresponding user-space
4963 * spin too long if we get preempted.
4968 userpg->index = perf_event_index(event);
4969 userpg->offset = perf_event_count(event);
4971 userpg->offset -= local64_read(&event->hw.prev_count);
4973 userpg->time_enabled = enabled +
4974 atomic64_read(&event->child_total_time_enabled);
4976 userpg->time_running = running +
4977 atomic64_read(&event->child_total_time_running);
4979 arch_perf_update_userpage(event, userpg, now);
4988 static int perf_mmap_fault(struct vm_fault *vmf)
4990 struct perf_event *event = vmf->vma->vm_file->private_data;
4991 struct ring_buffer *rb;
4992 int ret = VM_FAULT_SIGBUS;
4994 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4995 if (vmf->pgoff == 0)
5001 rb = rcu_dereference(event->rb);
5005 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5008 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5012 get_page(vmf->page);
5013 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5014 vmf->page->index = vmf->pgoff;
5023 static void ring_buffer_attach(struct perf_event *event,
5024 struct ring_buffer *rb)
5026 struct ring_buffer *old_rb = NULL;
5027 unsigned long flags;
5031 * Should be impossible, we set this when removing
5032 * event->rb_entry and wait/clear when adding event->rb_entry.
5034 WARN_ON_ONCE(event->rcu_pending);
5037 spin_lock_irqsave(&old_rb->event_lock, flags);
5038 list_del_rcu(&event->rb_entry);
5039 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5041 event->rcu_batches = get_state_synchronize_rcu();
5042 event->rcu_pending = 1;
5046 if (event->rcu_pending) {
5047 cond_synchronize_rcu(event->rcu_batches);
5048 event->rcu_pending = 0;
5051 spin_lock_irqsave(&rb->event_lock, flags);
5052 list_add_rcu(&event->rb_entry, &rb->event_list);
5053 spin_unlock_irqrestore(&rb->event_lock, flags);
5057 * Avoid racing with perf_mmap_close(AUX): stop the event
5058 * before swizzling the event::rb pointer; if it's getting
5059 * unmapped, its aux_mmap_count will be 0 and it won't
5060 * restart. See the comment in __perf_pmu_output_stop().
5062 * Data will inevitably be lost when set_output is done in
5063 * mid-air, but then again, whoever does it like this is
5064 * not in for the data anyway.
5067 perf_event_stop(event, 0);
5069 rcu_assign_pointer(event->rb, rb);
5072 ring_buffer_put(old_rb);
5074 * Since we detached before setting the new rb, so that we
5075 * could attach the new rb, we could have missed a wakeup.
5078 wake_up_all(&event->waitq);
5082 static void ring_buffer_wakeup(struct perf_event *event)
5084 struct ring_buffer *rb;
5087 rb = rcu_dereference(event->rb);
5089 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5090 wake_up_all(&event->waitq);
5095 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5097 struct ring_buffer *rb;
5100 rb = rcu_dereference(event->rb);
5102 if (!atomic_inc_not_zero(&rb->refcount))
5110 void ring_buffer_put(struct ring_buffer *rb)
5112 if (!atomic_dec_and_test(&rb->refcount))
5115 WARN_ON_ONCE(!list_empty(&rb->event_list));
5117 call_rcu(&rb->rcu_head, rb_free_rcu);
5120 static void perf_mmap_open(struct vm_area_struct *vma)
5122 struct perf_event *event = vma->vm_file->private_data;
5124 atomic_inc(&event->mmap_count);
5125 atomic_inc(&event->rb->mmap_count);
5128 atomic_inc(&event->rb->aux_mmap_count);
5130 if (event->pmu->event_mapped)
5131 event->pmu->event_mapped(event, vma->vm_mm);
5134 static void perf_pmu_output_stop(struct perf_event *event);
5137 * A buffer can be mmap()ed multiple times; either directly through the same
5138 * event, or through other events by use of perf_event_set_output().
5140 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5141 * the buffer here, where we still have a VM context. This means we need
5142 * to detach all events redirecting to us.
5144 static void perf_mmap_close(struct vm_area_struct *vma)
5146 struct perf_event *event = vma->vm_file->private_data;
5148 struct ring_buffer *rb = ring_buffer_get(event);
5149 struct user_struct *mmap_user = rb->mmap_user;
5150 int mmap_locked = rb->mmap_locked;
5151 unsigned long size = perf_data_size(rb);
5153 if (event->pmu->event_unmapped)
5154 event->pmu->event_unmapped(event, vma->vm_mm);
5157 * rb->aux_mmap_count will always drop before rb->mmap_count and
5158 * event->mmap_count, so it is ok to use event->mmap_mutex to
5159 * serialize with perf_mmap here.
5161 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5162 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5164 * Stop all AUX events that are writing to this buffer,
5165 * so that we can free its AUX pages and corresponding PMU
5166 * data. Note that after rb::aux_mmap_count dropped to zero,
5167 * they won't start any more (see perf_aux_output_begin()).
5169 perf_pmu_output_stop(event);
5171 /* now it's safe to free the pages */
5172 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5173 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5175 /* this has to be the last one */
5177 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5179 mutex_unlock(&event->mmap_mutex);
5182 atomic_dec(&rb->mmap_count);
5184 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5187 ring_buffer_attach(event, NULL);
5188 mutex_unlock(&event->mmap_mutex);
5190 /* If there's still other mmap()s of this buffer, we're done. */
5191 if (atomic_read(&rb->mmap_count))
5195 * No other mmap()s, detach from all other events that might redirect
5196 * into the now unreachable buffer. Somewhat complicated by the
5197 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5201 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5202 if (!atomic_long_inc_not_zero(&event->refcount)) {
5204 * This event is en-route to free_event() which will
5205 * detach it and remove it from the list.
5211 mutex_lock(&event->mmap_mutex);
5213 * Check we didn't race with perf_event_set_output() which can
5214 * swizzle the rb from under us while we were waiting to
5215 * acquire mmap_mutex.
5217 * If we find a different rb; ignore this event, a next
5218 * iteration will no longer find it on the list. We have to
5219 * still restart the iteration to make sure we're not now
5220 * iterating the wrong list.
5222 if (event->rb == rb)
5223 ring_buffer_attach(event, NULL);
5225 mutex_unlock(&event->mmap_mutex);
5229 * Restart the iteration; either we're on the wrong list or
5230 * destroyed its integrity by doing a deletion.
5237 * It could be there's still a few 0-ref events on the list; they'll
5238 * get cleaned up by free_event() -- they'll also still have their
5239 * ref on the rb and will free it whenever they are done with it.
5241 * Aside from that, this buffer is 'fully' detached and unmapped,
5242 * undo the VM accounting.
5245 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5246 vma->vm_mm->pinned_vm -= mmap_locked;
5247 free_uid(mmap_user);
5250 ring_buffer_put(rb); /* could be last */
5253 static const struct vm_operations_struct perf_mmap_vmops = {
5254 .open = perf_mmap_open,
5255 .close = perf_mmap_close, /* non mergable */
5256 .fault = perf_mmap_fault,
5257 .page_mkwrite = perf_mmap_fault,
5260 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5262 struct perf_event *event = file->private_data;
5263 unsigned long user_locked, user_lock_limit;
5264 struct user_struct *user = current_user();
5265 unsigned long locked, lock_limit;
5266 struct ring_buffer *rb = NULL;
5267 unsigned long vma_size;
5268 unsigned long nr_pages;
5269 long user_extra = 0, extra = 0;
5270 int ret = 0, flags = 0;
5273 * Don't allow mmap() of inherited per-task counters. This would
5274 * create a performance issue due to all children writing to the
5277 if (event->cpu == -1 && event->attr.inherit)
5280 if (!(vma->vm_flags & VM_SHARED))
5283 vma_size = vma->vm_end - vma->vm_start;
5285 if (vma->vm_pgoff == 0) {
5286 nr_pages = (vma_size / PAGE_SIZE) - 1;
5289 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5290 * mapped, all subsequent mappings should have the same size
5291 * and offset. Must be above the normal perf buffer.
5293 u64 aux_offset, aux_size;
5298 nr_pages = vma_size / PAGE_SIZE;
5300 mutex_lock(&event->mmap_mutex);
5307 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5308 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5310 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5313 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5316 /* already mapped with a different offset */
5317 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5320 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5323 /* already mapped with a different size */
5324 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5327 if (!is_power_of_2(nr_pages))
5330 if (!atomic_inc_not_zero(&rb->mmap_count))
5333 if (rb_has_aux(rb)) {
5334 atomic_inc(&rb->aux_mmap_count);
5339 atomic_set(&rb->aux_mmap_count, 1);
5340 user_extra = nr_pages;
5346 * If we have rb pages ensure they're a power-of-two number, so we
5347 * can do bitmasks instead of modulo.
5349 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5352 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5355 WARN_ON_ONCE(event->ctx->parent_ctx);
5357 mutex_lock(&event->mmap_mutex);
5359 if (event->rb->nr_pages != nr_pages) {
5364 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5366 * Raced against perf_mmap_close() through
5367 * perf_event_set_output(). Try again, hope for better
5370 mutex_unlock(&event->mmap_mutex);
5377 user_extra = nr_pages + 1;
5380 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5383 * Increase the limit linearly with more CPUs:
5385 user_lock_limit *= num_online_cpus();
5387 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5389 if (user_locked > user_lock_limit)
5390 extra = user_locked - user_lock_limit;
5392 lock_limit = rlimit(RLIMIT_MEMLOCK);
5393 lock_limit >>= PAGE_SHIFT;
5394 locked = vma->vm_mm->pinned_vm + extra;
5396 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5397 !capable(CAP_IPC_LOCK)) {
5402 WARN_ON(!rb && event->rb);
5404 if (vma->vm_flags & VM_WRITE)
5405 flags |= RING_BUFFER_WRITABLE;
5408 rb = rb_alloc(nr_pages,
5409 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5417 atomic_set(&rb->mmap_count, 1);
5418 rb->mmap_user = get_current_user();
5419 rb->mmap_locked = extra;
5421 ring_buffer_attach(event, rb);
5423 perf_event_init_userpage(event);
5424 perf_event_update_userpage(event);
5426 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5427 event->attr.aux_watermark, flags);
5429 rb->aux_mmap_locked = extra;
5434 atomic_long_add(user_extra, &user->locked_vm);
5435 vma->vm_mm->pinned_vm += extra;
5437 atomic_inc(&event->mmap_count);
5439 atomic_dec(&rb->mmap_count);
5442 mutex_unlock(&event->mmap_mutex);
5445 * Since pinned accounting is per vm we cannot allow fork() to copy our
5448 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5449 vma->vm_ops = &perf_mmap_vmops;
5451 if (event->pmu->event_mapped)
5452 event->pmu->event_mapped(event, vma->vm_mm);
5457 static int perf_fasync(int fd, struct file *filp, int on)
5459 struct inode *inode = file_inode(filp);
5460 struct perf_event *event = filp->private_data;
5464 retval = fasync_helper(fd, filp, on, &event->fasync);
5465 inode_unlock(inode);
5473 static const struct file_operations perf_fops = {
5474 .llseek = no_llseek,
5475 .release = perf_release,
5478 .unlocked_ioctl = perf_ioctl,
5479 .compat_ioctl = perf_compat_ioctl,
5481 .fasync = perf_fasync,
5487 * If there's data, ensure we set the poll() state and publish everything
5488 * to user-space before waking everybody up.
5491 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5493 /* only the parent has fasync state */
5495 event = event->parent;
5496 return &event->fasync;
5499 void perf_event_wakeup(struct perf_event *event)
5501 ring_buffer_wakeup(event);
5503 if (event->pending_kill) {
5504 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5505 event->pending_kill = 0;
5509 static void perf_pending_event(struct irq_work *entry)
5511 struct perf_event *event = container_of(entry,
5512 struct perf_event, pending);
5515 rctx = perf_swevent_get_recursion_context();
5517 * If we 'fail' here, that's OK, it means recursion is already disabled
5518 * and we won't recurse 'further'.
5521 if (event->pending_disable) {
5522 event->pending_disable = 0;
5523 perf_event_disable_local(event);
5526 if (event->pending_wakeup) {
5527 event->pending_wakeup = 0;
5528 perf_event_wakeup(event);
5532 perf_swevent_put_recursion_context(rctx);
5536 * We assume there is only KVM supporting the callbacks.
5537 * Later on, we might change it to a list if there is
5538 * another virtualization implementation supporting the callbacks.
5540 struct perf_guest_info_callbacks *perf_guest_cbs;
5542 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5544 perf_guest_cbs = cbs;
5547 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5549 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5551 perf_guest_cbs = NULL;
5554 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5557 perf_output_sample_regs(struct perf_output_handle *handle,
5558 struct pt_regs *regs, u64 mask)
5561 DECLARE_BITMAP(_mask, 64);
5563 bitmap_from_u64(_mask, mask);
5564 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5567 val = perf_reg_value(regs, bit);
5568 perf_output_put(handle, val);
5572 static void perf_sample_regs_user(struct perf_regs *regs_user,
5573 struct pt_regs *regs,
5574 struct pt_regs *regs_user_copy)
5576 if (user_mode(regs)) {
5577 regs_user->abi = perf_reg_abi(current);
5578 regs_user->regs = regs;
5579 } else if (current->mm) {
5580 perf_get_regs_user(regs_user, regs, regs_user_copy);
5582 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5583 regs_user->regs = NULL;
5587 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5588 struct pt_regs *regs)
5590 regs_intr->regs = regs;
5591 regs_intr->abi = perf_reg_abi(current);
5596 * Get remaining task size from user stack pointer.
5598 * It'd be better to take stack vma map and limit this more
5599 * precisly, but there's no way to get it safely under interrupt,
5600 * so using TASK_SIZE as limit.
5602 static u64 perf_ustack_task_size(struct pt_regs *regs)
5604 unsigned long addr = perf_user_stack_pointer(regs);
5606 if (!addr || addr >= TASK_SIZE)
5609 return TASK_SIZE - addr;
5613 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5614 struct pt_regs *regs)
5618 /* No regs, no stack pointer, no dump. */
5623 * Check if we fit in with the requested stack size into the:
5625 * If we don't, we limit the size to the TASK_SIZE.
5627 * - remaining sample size
5628 * If we don't, we customize the stack size to
5629 * fit in to the remaining sample size.
5632 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5633 stack_size = min(stack_size, (u16) task_size);
5635 /* Current header size plus static size and dynamic size. */
5636 header_size += 2 * sizeof(u64);
5638 /* Do we fit in with the current stack dump size? */
5639 if ((u16) (header_size + stack_size) < header_size) {
5641 * If we overflow the maximum size for the sample,
5642 * we customize the stack dump size to fit in.
5644 stack_size = USHRT_MAX - header_size - sizeof(u64);
5645 stack_size = round_up(stack_size, sizeof(u64));
5652 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5653 struct pt_regs *regs)
5655 /* Case of a kernel thread, nothing to dump */
5658 perf_output_put(handle, size);
5667 * - the size requested by user or the best one we can fit
5668 * in to the sample max size
5670 * - user stack dump data
5672 * - the actual dumped size
5676 perf_output_put(handle, dump_size);
5679 sp = perf_user_stack_pointer(regs);
5680 rem = __output_copy_user(handle, (void *) sp, dump_size);
5681 dyn_size = dump_size - rem;
5683 perf_output_skip(handle, rem);
5686 perf_output_put(handle, dyn_size);
5690 static void __perf_event_header__init_id(struct perf_event_header *header,
5691 struct perf_sample_data *data,
5692 struct perf_event *event)
5694 u64 sample_type = event->attr.sample_type;
5696 data->type = sample_type;
5697 header->size += event->id_header_size;
5699 if (sample_type & PERF_SAMPLE_TID) {
5700 /* namespace issues */
5701 data->tid_entry.pid = perf_event_pid(event, current);
5702 data->tid_entry.tid = perf_event_tid(event, current);
5705 if (sample_type & PERF_SAMPLE_TIME)
5706 data->time = perf_event_clock(event);
5708 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5709 data->id = primary_event_id(event);
5711 if (sample_type & PERF_SAMPLE_STREAM_ID)
5712 data->stream_id = event->id;
5714 if (sample_type & PERF_SAMPLE_CPU) {
5715 data->cpu_entry.cpu = raw_smp_processor_id();
5716 data->cpu_entry.reserved = 0;
5720 void perf_event_header__init_id(struct perf_event_header *header,
5721 struct perf_sample_data *data,
5722 struct perf_event *event)
5724 if (event->attr.sample_id_all)
5725 __perf_event_header__init_id(header, data, event);
5728 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5729 struct perf_sample_data *data)
5731 u64 sample_type = data->type;
5733 if (sample_type & PERF_SAMPLE_TID)
5734 perf_output_put(handle, data->tid_entry);
5736 if (sample_type & PERF_SAMPLE_TIME)
5737 perf_output_put(handle, data->time);
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_IDENTIFIER)
5749 perf_output_put(handle, data->id);
5752 void perf_event__output_id_sample(struct perf_event *event,
5753 struct perf_output_handle *handle,
5754 struct perf_sample_data *sample)
5756 if (event->attr.sample_id_all)
5757 __perf_event__output_id_sample(handle, sample);
5760 static void perf_output_read_one(struct perf_output_handle *handle,
5761 struct perf_event *event,
5762 u64 enabled, u64 running)
5764 u64 read_format = event->attr.read_format;
5768 values[n++] = perf_event_count(event);
5769 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5770 values[n++] = enabled +
5771 atomic64_read(&event->child_total_time_enabled);
5773 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5774 values[n++] = running +
5775 atomic64_read(&event->child_total_time_running);
5777 if (read_format & PERF_FORMAT_ID)
5778 values[n++] = primary_event_id(event);
5780 __output_copy(handle, values, n * sizeof(u64));
5783 static void perf_output_read_group(struct perf_output_handle *handle,
5784 struct perf_event *event,
5785 u64 enabled, u64 running)
5787 struct perf_event *leader = event->group_leader, *sub;
5788 u64 read_format = event->attr.read_format;
5792 values[n++] = 1 + leader->nr_siblings;
5794 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5795 values[n++] = enabled;
5797 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5798 values[n++] = running;
5800 if (leader != event)
5801 leader->pmu->read(leader);
5803 values[n++] = perf_event_count(leader);
5804 if (read_format & PERF_FORMAT_ID)
5805 values[n++] = primary_event_id(leader);
5807 __output_copy(handle, values, n * sizeof(u64));
5809 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5812 if ((sub != event) &&
5813 (sub->state == PERF_EVENT_STATE_ACTIVE))
5814 sub->pmu->read(sub);
5816 values[n++] = perf_event_count(sub);
5817 if (read_format & PERF_FORMAT_ID)
5818 values[n++] = primary_event_id(sub);
5820 __output_copy(handle, values, n * sizeof(u64));
5824 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5825 PERF_FORMAT_TOTAL_TIME_RUNNING)
5828 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5830 * The problem is that its both hard and excessively expensive to iterate the
5831 * child list, not to mention that its impossible to IPI the children running
5832 * on another CPU, from interrupt/NMI context.
5834 static void perf_output_read(struct perf_output_handle *handle,
5835 struct perf_event *event)
5837 u64 enabled = 0, running = 0, now;
5838 u64 read_format = event->attr.read_format;
5841 * compute total_time_enabled, total_time_running
5842 * based on snapshot values taken when the event
5843 * was last scheduled in.
5845 * we cannot simply called update_context_time()
5846 * because of locking issue as we are called in
5849 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5850 calc_timer_values(event, &now, &enabled, &running);
5852 if (event->attr.read_format & PERF_FORMAT_GROUP)
5853 perf_output_read_group(handle, event, enabled, running);
5855 perf_output_read_one(handle, event, enabled, running);
5858 void perf_output_sample(struct perf_output_handle *handle,
5859 struct perf_event_header *header,
5860 struct perf_sample_data *data,
5861 struct perf_event *event)
5863 u64 sample_type = data->type;
5865 perf_output_put(handle, *header);
5867 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5868 perf_output_put(handle, data->id);
5870 if (sample_type & PERF_SAMPLE_IP)
5871 perf_output_put(handle, data->ip);
5873 if (sample_type & PERF_SAMPLE_TID)
5874 perf_output_put(handle, data->tid_entry);
5876 if (sample_type & PERF_SAMPLE_TIME)
5877 perf_output_put(handle, data->time);
5879 if (sample_type & PERF_SAMPLE_ADDR)
5880 perf_output_put(handle, data->addr);
5882 if (sample_type & PERF_SAMPLE_ID)
5883 perf_output_put(handle, data->id);
5885 if (sample_type & PERF_SAMPLE_STREAM_ID)
5886 perf_output_put(handle, data->stream_id);
5888 if (sample_type & PERF_SAMPLE_CPU)
5889 perf_output_put(handle, data->cpu_entry);
5891 if (sample_type & PERF_SAMPLE_PERIOD)
5892 perf_output_put(handle, data->period);
5894 if (sample_type & PERF_SAMPLE_READ)
5895 perf_output_read(handle, event);
5897 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5898 if (data->callchain) {
5901 if (data->callchain)
5902 size += data->callchain->nr;
5904 size *= sizeof(u64);
5906 __output_copy(handle, data->callchain, size);
5909 perf_output_put(handle, nr);
5913 if (sample_type & PERF_SAMPLE_RAW) {
5914 struct perf_raw_record *raw = data->raw;
5917 struct perf_raw_frag *frag = &raw->frag;
5919 perf_output_put(handle, raw->size);
5922 __output_custom(handle, frag->copy,
5923 frag->data, frag->size);
5925 __output_copy(handle, frag->data,
5928 if (perf_raw_frag_last(frag))
5933 __output_skip(handle, NULL, frag->pad);
5939 .size = sizeof(u32),
5942 perf_output_put(handle, raw);
5946 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5947 if (data->br_stack) {
5950 size = data->br_stack->nr
5951 * sizeof(struct perf_branch_entry);
5953 perf_output_put(handle, data->br_stack->nr);
5954 perf_output_copy(handle, data->br_stack->entries, size);
5957 * we always store at least the value of nr
5960 perf_output_put(handle, nr);
5964 if (sample_type & PERF_SAMPLE_REGS_USER) {
5965 u64 abi = data->regs_user.abi;
5968 * If there are no regs to dump, notice it through
5969 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5971 perf_output_put(handle, abi);
5974 u64 mask = event->attr.sample_regs_user;
5975 perf_output_sample_regs(handle,
5976 data->regs_user.regs,
5981 if (sample_type & PERF_SAMPLE_STACK_USER) {
5982 perf_output_sample_ustack(handle,
5983 data->stack_user_size,
5984 data->regs_user.regs);
5987 if (sample_type & PERF_SAMPLE_WEIGHT)
5988 perf_output_put(handle, data->weight);
5990 if (sample_type & PERF_SAMPLE_DATA_SRC)
5991 perf_output_put(handle, data->data_src.val);
5993 if (sample_type & PERF_SAMPLE_TRANSACTION)
5994 perf_output_put(handle, data->txn);
5996 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5997 u64 abi = data->regs_intr.abi;
5999 * If there are no regs to dump, notice it through
6000 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6002 perf_output_put(handle, abi);
6005 u64 mask = event->attr.sample_regs_intr;
6007 perf_output_sample_regs(handle,
6008 data->regs_intr.regs,
6013 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6014 perf_output_put(handle, data->phys_addr);
6016 if (!event->attr.watermark) {
6017 int wakeup_events = event->attr.wakeup_events;
6019 if (wakeup_events) {
6020 struct ring_buffer *rb = handle->rb;
6021 int events = local_inc_return(&rb->events);
6023 if (events >= wakeup_events) {
6024 local_sub(wakeup_events, &rb->events);
6025 local_inc(&rb->wakeup);
6031 static u64 perf_virt_to_phys(u64 virt)
6034 struct page *p = NULL;
6039 if (virt >= TASK_SIZE) {
6040 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6041 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6042 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6043 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6046 * Walking the pages tables for user address.
6047 * Interrupts are disabled, so it prevents any tear down
6048 * of the page tables.
6049 * Try IRQ-safe __get_user_pages_fast first.
6050 * If failed, leave phys_addr as 0.
6052 if ((current->mm != NULL) &&
6053 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6054 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6063 void perf_prepare_sample(struct perf_event_header *header,
6064 struct perf_sample_data *data,
6065 struct perf_event *event,
6066 struct pt_regs *regs)
6068 u64 sample_type = event->attr.sample_type;
6070 header->type = PERF_RECORD_SAMPLE;
6071 header->size = sizeof(*header) + event->header_size;
6074 header->misc |= perf_misc_flags(regs);
6076 __perf_event_header__init_id(header, data, event);
6078 if (sample_type & PERF_SAMPLE_IP)
6079 data->ip = perf_instruction_pointer(regs);
6081 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6084 data->callchain = perf_callchain(event, regs);
6086 if (data->callchain)
6087 size += data->callchain->nr;
6089 header->size += size * sizeof(u64);
6092 if (sample_type & PERF_SAMPLE_RAW) {
6093 struct perf_raw_record *raw = data->raw;
6097 struct perf_raw_frag *frag = &raw->frag;
6102 if (perf_raw_frag_last(frag))
6107 size = round_up(sum + sizeof(u32), sizeof(u64));
6108 raw->size = size - sizeof(u32);
6109 frag->pad = raw->size - sum;
6114 header->size += size;
6117 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6118 int size = sizeof(u64); /* nr */
6119 if (data->br_stack) {
6120 size += data->br_stack->nr
6121 * sizeof(struct perf_branch_entry);
6123 header->size += size;
6126 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6127 perf_sample_regs_user(&data->regs_user, regs,
6128 &data->regs_user_copy);
6130 if (sample_type & PERF_SAMPLE_REGS_USER) {
6131 /* regs dump ABI info */
6132 int size = sizeof(u64);
6134 if (data->regs_user.regs) {
6135 u64 mask = event->attr.sample_regs_user;
6136 size += hweight64(mask) * sizeof(u64);
6139 header->size += size;
6142 if (sample_type & PERF_SAMPLE_STACK_USER) {
6144 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6145 * processed as the last one or have additional check added
6146 * in case new sample type is added, because we could eat
6147 * up the rest of the sample size.
6149 u16 stack_size = event->attr.sample_stack_user;
6150 u16 size = sizeof(u64);
6152 stack_size = perf_sample_ustack_size(stack_size, header->size,
6153 data->regs_user.regs);
6156 * If there is something to dump, add space for the dump
6157 * itself and for the field that tells the dynamic size,
6158 * which is how many have been actually dumped.
6161 size += sizeof(u64) + stack_size;
6163 data->stack_user_size = stack_size;
6164 header->size += size;
6167 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6168 /* regs dump ABI info */
6169 int size = sizeof(u64);
6171 perf_sample_regs_intr(&data->regs_intr, regs);
6173 if (data->regs_intr.regs) {
6174 u64 mask = event->attr.sample_regs_intr;
6176 size += hweight64(mask) * sizeof(u64);
6179 header->size += size;
6182 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6183 data->phys_addr = perf_virt_to_phys(data->addr);
6186 static void __always_inline
6187 __perf_event_output(struct perf_event *event,
6188 struct perf_sample_data *data,
6189 struct pt_regs *regs,
6190 int (*output_begin)(struct perf_output_handle *,
6191 struct perf_event *,
6194 struct perf_output_handle handle;
6195 struct perf_event_header header;
6197 /* protect the callchain buffers */
6200 perf_prepare_sample(&header, data, event, regs);
6202 if (output_begin(&handle, event, header.size))
6205 perf_output_sample(&handle, &header, data, event);
6207 perf_output_end(&handle);
6214 perf_event_output_forward(struct perf_event *event,
6215 struct perf_sample_data *data,
6216 struct pt_regs *regs)
6218 __perf_event_output(event, data, regs, perf_output_begin_forward);
6222 perf_event_output_backward(struct perf_event *event,
6223 struct perf_sample_data *data,
6224 struct pt_regs *regs)
6226 __perf_event_output(event, data, regs, perf_output_begin_backward);
6230 perf_event_output(struct perf_event *event,
6231 struct perf_sample_data *data,
6232 struct pt_regs *regs)
6234 __perf_event_output(event, data, regs, perf_output_begin);
6241 struct perf_read_event {
6242 struct perf_event_header header;
6249 perf_event_read_event(struct perf_event *event,
6250 struct task_struct *task)
6252 struct perf_output_handle handle;
6253 struct perf_sample_data sample;
6254 struct perf_read_event read_event = {
6256 .type = PERF_RECORD_READ,
6258 .size = sizeof(read_event) + event->read_size,
6260 .pid = perf_event_pid(event, task),
6261 .tid = perf_event_tid(event, task),
6265 perf_event_header__init_id(&read_event.header, &sample, event);
6266 ret = perf_output_begin(&handle, event, read_event.header.size);
6270 perf_output_put(&handle, read_event);
6271 perf_output_read(&handle, event);
6272 perf_event__output_id_sample(event, &handle, &sample);
6274 perf_output_end(&handle);
6277 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6280 perf_iterate_ctx(struct perf_event_context *ctx,
6281 perf_iterate_f output,
6282 void *data, bool all)
6284 struct perf_event *event;
6286 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6288 if (event->state < PERF_EVENT_STATE_INACTIVE)
6290 if (!event_filter_match(event))
6294 output(event, data);
6298 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6300 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6301 struct perf_event *event;
6303 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6305 * Skip events that are not fully formed yet; ensure that
6306 * if we observe event->ctx, both event and ctx will be
6307 * complete enough. See perf_install_in_context().
6309 if (!smp_load_acquire(&event->ctx))
6312 if (event->state < PERF_EVENT_STATE_INACTIVE)
6314 if (!event_filter_match(event))
6316 output(event, data);
6321 * Iterate all events that need to receive side-band events.
6323 * For new callers; ensure that account_pmu_sb_event() includes
6324 * your event, otherwise it might not get delivered.
6327 perf_iterate_sb(perf_iterate_f output, void *data,
6328 struct perf_event_context *task_ctx)
6330 struct perf_event_context *ctx;
6337 * If we have task_ctx != NULL we only notify the task context itself.
6338 * The task_ctx is set only for EXIT events before releasing task
6342 perf_iterate_ctx(task_ctx, output, data, false);
6346 perf_iterate_sb_cpu(output, data);
6348 for_each_task_context_nr(ctxn) {
6349 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6351 perf_iterate_ctx(ctx, output, data, false);
6359 * Clear all file-based filters at exec, they'll have to be
6360 * re-instated when/if these objects are mmapped again.
6362 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6364 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6365 struct perf_addr_filter *filter;
6366 unsigned int restart = 0, count = 0;
6367 unsigned long flags;
6369 if (!has_addr_filter(event))
6372 raw_spin_lock_irqsave(&ifh->lock, flags);
6373 list_for_each_entry(filter, &ifh->list, entry) {
6374 if (filter->inode) {
6375 event->addr_filters_offs[count] = 0;
6383 event->addr_filters_gen++;
6384 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6387 perf_event_stop(event, 1);
6390 void perf_event_exec(void)
6392 struct perf_event_context *ctx;
6396 for_each_task_context_nr(ctxn) {
6397 ctx = current->perf_event_ctxp[ctxn];
6401 perf_event_enable_on_exec(ctxn);
6403 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6409 struct remote_output {
6410 struct ring_buffer *rb;
6414 static void __perf_event_output_stop(struct perf_event *event, void *data)
6416 struct perf_event *parent = event->parent;
6417 struct remote_output *ro = data;
6418 struct ring_buffer *rb = ro->rb;
6419 struct stop_event_data sd = {
6423 if (!has_aux(event))
6430 * In case of inheritance, it will be the parent that links to the
6431 * ring-buffer, but it will be the child that's actually using it.
6433 * We are using event::rb to determine if the event should be stopped,
6434 * however this may race with ring_buffer_attach() (through set_output),
6435 * which will make us skip the event that actually needs to be stopped.
6436 * So ring_buffer_attach() has to stop an aux event before re-assigning
6439 if (rcu_dereference(parent->rb) == rb)
6440 ro->err = __perf_event_stop(&sd);
6443 static int __perf_pmu_output_stop(void *info)
6445 struct perf_event *event = info;
6446 struct pmu *pmu = event->pmu;
6447 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6448 struct remote_output ro = {
6453 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6454 if (cpuctx->task_ctx)
6455 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6462 static void perf_pmu_output_stop(struct perf_event *event)
6464 struct perf_event *iter;
6469 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6471 * For per-CPU events, we need to make sure that neither they
6472 * nor their children are running; for cpu==-1 events it's
6473 * sufficient to stop the event itself if it's active, since
6474 * it can't have children.
6478 cpu = READ_ONCE(iter->oncpu);
6483 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6484 if (err == -EAGAIN) {
6493 * task tracking -- fork/exit
6495 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6498 struct perf_task_event {
6499 struct task_struct *task;
6500 struct perf_event_context *task_ctx;
6503 struct perf_event_header header;
6513 static int perf_event_task_match(struct perf_event *event)
6515 return event->attr.comm || event->attr.mmap ||
6516 event->attr.mmap2 || event->attr.mmap_data ||
6520 static void perf_event_task_output(struct perf_event *event,
6523 struct perf_task_event *task_event = data;
6524 struct perf_output_handle handle;
6525 struct perf_sample_data sample;
6526 struct task_struct *task = task_event->task;
6527 int ret, size = task_event->event_id.header.size;
6529 if (!perf_event_task_match(event))
6532 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6534 ret = perf_output_begin(&handle, event,
6535 task_event->event_id.header.size);
6539 task_event->event_id.pid = perf_event_pid(event, task);
6540 task_event->event_id.ppid = perf_event_pid(event, current);
6542 task_event->event_id.tid = perf_event_tid(event, task);
6543 task_event->event_id.ptid = perf_event_tid(event, current);
6545 task_event->event_id.time = perf_event_clock(event);
6547 perf_output_put(&handle, task_event->event_id);
6549 perf_event__output_id_sample(event, &handle, &sample);
6551 perf_output_end(&handle);
6553 task_event->event_id.header.size = size;
6556 static void perf_event_task(struct task_struct *task,
6557 struct perf_event_context *task_ctx,
6560 struct perf_task_event task_event;
6562 if (!atomic_read(&nr_comm_events) &&
6563 !atomic_read(&nr_mmap_events) &&
6564 !atomic_read(&nr_task_events))
6567 task_event = (struct perf_task_event){
6569 .task_ctx = task_ctx,
6572 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6574 .size = sizeof(task_event.event_id),
6584 perf_iterate_sb(perf_event_task_output,
6589 void perf_event_fork(struct task_struct *task)
6591 perf_event_task(task, NULL, 1);
6592 perf_event_namespaces(task);
6599 struct perf_comm_event {
6600 struct task_struct *task;
6605 struct perf_event_header header;
6612 static int perf_event_comm_match(struct perf_event *event)
6614 return event->attr.comm;
6617 static void perf_event_comm_output(struct perf_event *event,
6620 struct perf_comm_event *comm_event = data;
6621 struct perf_output_handle handle;
6622 struct perf_sample_data sample;
6623 int size = comm_event->event_id.header.size;
6626 if (!perf_event_comm_match(event))
6629 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6630 ret = perf_output_begin(&handle, event,
6631 comm_event->event_id.header.size);
6636 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6637 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6639 perf_output_put(&handle, comm_event->event_id);
6640 __output_copy(&handle, comm_event->comm,
6641 comm_event->comm_size);
6643 perf_event__output_id_sample(event, &handle, &sample);
6645 perf_output_end(&handle);
6647 comm_event->event_id.header.size = size;
6650 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6652 char comm[TASK_COMM_LEN];
6655 memset(comm, 0, sizeof(comm));
6656 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6657 size = ALIGN(strlen(comm)+1, sizeof(u64));
6659 comm_event->comm = comm;
6660 comm_event->comm_size = size;
6662 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6664 perf_iterate_sb(perf_event_comm_output,
6669 void perf_event_comm(struct task_struct *task, bool exec)
6671 struct perf_comm_event comm_event;
6673 if (!atomic_read(&nr_comm_events))
6676 comm_event = (struct perf_comm_event){
6682 .type = PERF_RECORD_COMM,
6683 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6691 perf_event_comm_event(&comm_event);
6695 * namespaces tracking
6698 struct perf_namespaces_event {
6699 struct task_struct *task;
6702 struct perf_event_header header;
6707 struct perf_ns_link_info link_info[NR_NAMESPACES];
6711 static int perf_event_namespaces_match(struct perf_event *event)
6713 return event->attr.namespaces;
6716 static void perf_event_namespaces_output(struct perf_event *event,
6719 struct perf_namespaces_event *namespaces_event = data;
6720 struct perf_output_handle handle;
6721 struct perf_sample_data sample;
6722 u16 header_size = namespaces_event->event_id.header.size;
6725 if (!perf_event_namespaces_match(event))
6728 perf_event_header__init_id(&namespaces_event->event_id.header,
6730 ret = perf_output_begin(&handle, event,
6731 namespaces_event->event_id.header.size);
6735 namespaces_event->event_id.pid = perf_event_pid(event,
6736 namespaces_event->task);
6737 namespaces_event->event_id.tid = perf_event_tid(event,
6738 namespaces_event->task);
6740 perf_output_put(&handle, namespaces_event->event_id);
6742 perf_event__output_id_sample(event, &handle, &sample);
6744 perf_output_end(&handle);
6746 namespaces_event->event_id.header.size = header_size;
6749 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6750 struct task_struct *task,
6751 const struct proc_ns_operations *ns_ops)
6753 struct path ns_path;
6754 struct inode *ns_inode;
6757 error = ns_get_path(&ns_path, task, ns_ops);
6759 ns_inode = ns_path.dentry->d_inode;
6760 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6761 ns_link_info->ino = ns_inode->i_ino;
6766 void perf_event_namespaces(struct task_struct *task)
6768 struct perf_namespaces_event namespaces_event;
6769 struct perf_ns_link_info *ns_link_info;
6771 if (!atomic_read(&nr_namespaces_events))
6774 namespaces_event = (struct perf_namespaces_event){
6778 .type = PERF_RECORD_NAMESPACES,
6780 .size = sizeof(namespaces_event.event_id),
6784 .nr_namespaces = NR_NAMESPACES,
6785 /* .link_info[NR_NAMESPACES] */
6789 ns_link_info = namespaces_event.event_id.link_info;
6791 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6792 task, &mntns_operations);
6794 #ifdef CONFIG_USER_NS
6795 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6796 task, &userns_operations);
6798 #ifdef CONFIG_NET_NS
6799 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6800 task, &netns_operations);
6802 #ifdef CONFIG_UTS_NS
6803 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6804 task, &utsns_operations);
6806 #ifdef CONFIG_IPC_NS
6807 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6808 task, &ipcns_operations);
6810 #ifdef CONFIG_PID_NS
6811 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6812 task, &pidns_operations);
6814 #ifdef CONFIG_CGROUPS
6815 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6816 task, &cgroupns_operations);
6819 perf_iterate_sb(perf_event_namespaces_output,
6828 struct perf_mmap_event {
6829 struct vm_area_struct *vma;
6831 const char *file_name;
6839 struct perf_event_header header;
6849 static int perf_event_mmap_match(struct perf_event *event,
6852 struct perf_mmap_event *mmap_event = data;
6853 struct vm_area_struct *vma = mmap_event->vma;
6854 int executable = vma->vm_flags & VM_EXEC;
6856 return (!executable && event->attr.mmap_data) ||
6857 (executable && (event->attr.mmap || event->attr.mmap2));
6860 static void perf_event_mmap_output(struct perf_event *event,
6863 struct perf_mmap_event *mmap_event = data;
6864 struct perf_output_handle handle;
6865 struct perf_sample_data sample;
6866 int size = mmap_event->event_id.header.size;
6869 if (!perf_event_mmap_match(event, data))
6872 if (event->attr.mmap2) {
6873 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6874 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6875 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6876 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6877 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6878 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6879 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6882 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6883 ret = perf_output_begin(&handle, event,
6884 mmap_event->event_id.header.size);
6888 mmap_event->event_id.pid = perf_event_pid(event, current);
6889 mmap_event->event_id.tid = perf_event_tid(event, current);
6891 perf_output_put(&handle, mmap_event->event_id);
6893 if (event->attr.mmap2) {
6894 perf_output_put(&handle, mmap_event->maj);
6895 perf_output_put(&handle, mmap_event->min);
6896 perf_output_put(&handle, mmap_event->ino);
6897 perf_output_put(&handle, mmap_event->ino_generation);
6898 perf_output_put(&handle, mmap_event->prot);
6899 perf_output_put(&handle, mmap_event->flags);
6902 __output_copy(&handle, mmap_event->file_name,
6903 mmap_event->file_size);
6905 perf_event__output_id_sample(event, &handle, &sample);
6907 perf_output_end(&handle);
6909 mmap_event->event_id.header.size = size;
6912 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6914 struct vm_area_struct *vma = mmap_event->vma;
6915 struct file *file = vma->vm_file;
6916 int maj = 0, min = 0;
6917 u64 ino = 0, gen = 0;
6918 u32 prot = 0, flags = 0;
6924 if (vma->vm_flags & VM_READ)
6926 if (vma->vm_flags & VM_WRITE)
6928 if (vma->vm_flags & VM_EXEC)
6931 if (vma->vm_flags & VM_MAYSHARE)
6934 flags = MAP_PRIVATE;
6936 if (vma->vm_flags & VM_DENYWRITE)
6937 flags |= MAP_DENYWRITE;
6938 if (vma->vm_flags & VM_MAYEXEC)
6939 flags |= MAP_EXECUTABLE;
6940 if (vma->vm_flags & VM_LOCKED)
6941 flags |= MAP_LOCKED;
6942 if (vma->vm_flags & VM_HUGETLB)
6943 flags |= MAP_HUGETLB;
6946 struct inode *inode;
6949 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6955 * d_path() works from the end of the rb backwards, so we
6956 * need to add enough zero bytes after the string to handle
6957 * the 64bit alignment we do later.
6959 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6964 inode = file_inode(vma->vm_file);
6965 dev = inode->i_sb->s_dev;
6967 gen = inode->i_generation;
6973 if (vma->vm_ops && vma->vm_ops->name) {
6974 name = (char *) vma->vm_ops->name(vma);
6979 name = (char *)arch_vma_name(vma);
6983 if (vma->vm_start <= vma->vm_mm->start_brk &&
6984 vma->vm_end >= vma->vm_mm->brk) {
6988 if (vma->vm_start <= vma->vm_mm->start_stack &&
6989 vma->vm_end >= vma->vm_mm->start_stack) {
6999 strlcpy(tmp, name, sizeof(tmp));
7003 * Since our buffer works in 8 byte units we need to align our string
7004 * size to a multiple of 8. However, we must guarantee the tail end is
7005 * zero'd out to avoid leaking random bits to userspace.
7007 size = strlen(name)+1;
7008 while (!IS_ALIGNED(size, sizeof(u64)))
7009 name[size++] = '\0';
7011 mmap_event->file_name = name;
7012 mmap_event->file_size = size;
7013 mmap_event->maj = maj;
7014 mmap_event->min = min;
7015 mmap_event->ino = ino;
7016 mmap_event->ino_generation = gen;
7017 mmap_event->prot = prot;
7018 mmap_event->flags = flags;
7020 if (!(vma->vm_flags & VM_EXEC))
7021 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7023 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7025 perf_iterate_sb(perf_event_mmap_output,
7033 * Check whether inode and address range match filter criteria.
7035 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7036 struct file *file, unsigned long offset,
7039 if (filter->inode != file_inode(file))
7042 if (filter->offset > offset + size)
7045 if (filter->offset + filter->size < offset)
7051 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7053 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7054 struct vm_area_struct *vma = data;
7055 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7056 struct file *file = vma->vm_file;
7057 struct perf_addr_filter *filter;
7058 unsigned int restart = 0, count = 0;
7060 if (!has_addr_filter(event))
7066 raw_spin_lock_irqsave(&ifh->lock, flags);
7067 list_for_each_entry(filter, &ifh->list, entry) {
7068 if (perf_addr_filter_match(filter, file, off,
7069 vma->vm_end - vma->vm_start)) {
7070 event->addr_filters_offs[count] = vma->vm_start;
7078 event->addr_filters_gen++;
7079 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7082 perf_event_stop(event, 1);
7086 * Adjust all task's events' filters to the new vma
7088 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7090 struct perf_event_context *ctx;
7094 * Data tracing isn't supported yet and as such there is no need
7095 * to keep track of anything that isn't related to executable code:
7097 if (!(vma->vm_flags & VM_EXEC))
7101 for_each_task_context_nr(ctxn) {
7102 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7106 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7111 void perf_event_mmap(struct vm_area_struct *vma)
7113 struct perf_mmap_event mmap_event;
7115 if (!atomic_read(&nr_mmap_events))
7118 mmap_event = (struct perf_mmap_event){
7124 .type = PERF_RECORD_MMAP,
7125 .misc = PERF_RECORD_MISC_USER,
7130 .start = vma->vm_start,
7131 .len = vma->vm_end - vma->vm_start,
7132 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7134 /* .maj (attr_mmap2 only) */
7135 /* .min (attr_mmap2 only) */
7136 /* .ino (attr_mmap2 only) */
7137 /* .ino_generation (attr_mmap2 only) */
7138 /* .prot (attr_mmap2 only) */
7139 /* .flags (attr_mmap2 only) */
7142 perf_addr_filters_adjust(vma);
7143 perf_event_mmap_event(&mmap_event);
7146 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7147 unsigned long size, u64 flags)
7149 struct perf_output_handle handle;
7150 struct perf_sample_data sample;
7151 struct perf_aux_event {
7152 struct perf_event_header header;
7158 .type = PERF_RECORD_AUX,
7160 .size = sizeof(rec),
7168 perf_event_header__init_id(&rec.header, &sample, event);
7169 ret = perf_output_begin(&handle, event, rec.header.size);
7174 perf_output_put(&handle, rec);
7175 perf_event__output_id_sample(event, &handle, &sample);
7177 perf_output_end(&handle);
7181 * Lost/dropped samples logging
7183 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7185 struct perf_output_handle handle;
7186 struct perf_sample_data sample;
7190 struct perf_event_header header;
7192 } lost_samples_event = {
7194 .type = PERF_RECORD_LOST_SAMPLES,
7196 .size = sizeof(lost_samples_event),
7201 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7203 ret = perf_output_begin(&handle, event,
7204 lost_samples_event.header.size);
7208 perf_output_put(&handle, lost_samples_event);
7209 perf_event__output_id_sample(event, &handle, &sample);
7210 perf_output_end(&handle);
7214 * context_switch tracking
7217 struct perf_switch_event {
7218 struct task_struct *task;
7219 struct task_struct *next_prev;
7222 struct perf_event_header header;
7228 static int perf_event_switch_match(struct perf_event *event)
7230 return event->attr.context_switch;
7233 static void perf_event_switch_output(struct perf_event *event, void *data)
7235 struct perf_switch_event *se = data;
7236 struct perf_output_handle handle;
7237 struct perf_sample_data sample;
7240 if (!perf_event_switch_match(event))
7243 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7244 if (event->ctx->task) {
7245 se->event_id.header.type = PERF_RECORD_SWITCH;
7246 se->event_id.header.size = sizeof(se->event_id.header);
7248 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7249 se->event_id.header.size = sizeof(se->event_id);
7250 se->event_id.next_prev_pid =
7251 perf_event_pid(event, se->next_prev);
7252 se->event_id.next_prev_tid =
7253 perf_event_tid(event, se->next_prev);
7256 perf_event_header__init_id(&se->event_id.header, &sample, event);
7258 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7262 if (event->ctx->task)
7263 perf_output_put(&handle, se->event_id.header);
7265 perf_output_put(&handle, se->event_id);
7267 perf_event__output_id_sample(event, &handle, &sample);
7269 perf_output_end(&handle);
7272 static void perf_event_switch(struct task_struct *task,
7273 struct task_struct *next_prev, bool sched_in)
7275 struct perf_switch_event switch_event;
7277 /* N.B. caller checks nr_switch_events != 0 */
7279 switch_event = (struct perf_switch_event){
7281 .next_prev = next_prev,
7285 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7288 /* .next_prev_pid */
7289 /* .next_prev_tid */
7293 perf_iterate_sb(perf_event_switch_output,
7299 * IRQ throttle logging
7302 static void perf_log_throttle(struct perf_event *event, int enable)
7304 struct perf_output_handle handle;
7305 struct perf_sample_data sample;
7309 struct perf_event_header header;
7313 } throttle_event = {
7315 .type = PERF_RECORD_THROTTLE,
7317 .size = sizeof(throttle_event),
7319 .time = perf_event_clock(event),
7320 .id = primary_event_id(event),
7321 .stream_id = event->id,
7325 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7327 perf_event_header__init_id(&throttle_event.header, &sample, event);
7329 ret = perf_output_begin(&handle, event,
7330 throttle_event.header.size);
7334 perf_output_put(&handle, throttle_event);
7335 perf_event__output_id_sample(event, &handle, &sample);
7336 perf_output_end(&handle);
7339 void perf_event_itrace_started(struct perf_event *event)
7341 event->attach_state |= PERF_ATTACH_ITRACE;
7344 static void perf_log_itrace_start(struct perf_event *event)
7346 struct perf_output_handle handle;
7347 struct perf_sample_data sample;
7348 struct perf_aux_event {
7349 struct perf_event_header header;
7356 event = event->parent;
7358 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7359 event->attach_state & PERF_ATTACH_ITRACE)
7362 rec.header.type = PERF_RECORD_ITRACE_START;
7363 rec.header.misc = 0;
7364 rec.header.size = sizeof(rec);
7365 rec.pid = perf_event_pid(event, current);
7366 rec.tid = perf_event_tid(event, current);
7368 perf_event_header__init_id(&rec.header, &sample, event);
7369 ret = perf_output_begin(&handle, event, rec.header.size);
7374 perf_output_put(&handle, rec);
7375 perf_event__output_id_sample(event, &handle, &sample);
7377 perf_output_end(&handle);
7381 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7383 struct hw_perf_event *hwc = &event->hw;
7387 seq = __this_cpu_read(perf_throttled_seq);
7388 if (seq != hwc->interrupts_seq) {
7389 hwc->interrupts_seq = seq;
7390 hwc->interrupts = 1;
7393 if (unlikely(throttle
7394 && hwc->interrupts >= max_samples_per_tick)) {
7395 __this_cpu_inc(perf_throttled_count);
7396 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7397 hwc->interrupts = MAX_INTERRUPTS;
7398 perf_log_throttle(event, 0);
7403 if (event->attr.freq) {
7404 u64 now = perf_clock();
7405 s64 delta = now - hwc->freq_time_stamp;
7407 hwc->freq_time_stamp = now;
7409 if (delta > 0 && delta < 2*TICK_NSEC)
7410 perf_adjust_period(event, delta, hwc->last_period, true);
7416 int perf_event_account_interrupt(struct perf_event *event)
7418 return __perf_event_account_interrupt(event, 1);
7422 * Generic event overflow handling, sampling.
7425 static int __perf_event_overflow(struct perf_event *event,
7426 int throttle, struct perf_sample_data *data,
7427 struct pt_regs *regs)
7429 int events = atomic_read(&event->event_limit);
7433 * Non-sampling counters might still use the PMI to fold short
7434 * hardware counters, ignore those.
7436 if (unlikely(!is_sampling_event(event)))
7439 ret = __perf_event_account_interrupt(event, throttle);
7442 * XXX event_limit might not quite work as expected on inherited
7446 event->pending_kill = POLL_IN;
7447 if (events && atomic_dec_and_test(&event->event_limit)) {
7449 event->pending_kill = POLL_HUP;
7451 perf_event_disable_inatomic(event);
7454 READ_ONCE(event->overflow_handler)(event, data, regs);
7456 if (*perf_event_fasync(event) && event->pending_kill) {
7457 event->pending_wakeup = 1;
7458 irq_work_queue(&event->pending);
7464 int perf_event_overflow(struct perf_event *event,
7465 struct perf_sample_data *data,
7466 struct pt_regs *regs)
7468 return __perf_event_overflow(event, 1, data, regs);
7472 * Generic software event infrastructure
7475 struct swevent_htable {
7476 struct swevent_hlist *swevent_hlist;
7477 struct mutex hlist_mutex;
7480 /* Recursion avoidance in each contexts */
7481 int recursion[PERF_NR_CONTEXTS];
7484 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7487 * We directly increment event->count and keep a second value in
7488 * event->hw.period_left to count intervals. This period event
7489 * is kept in the range [-sample_period, 0] so that we can use the
7493 u64 perf_swevent_set_period(struct perf_event *event)
7495 struct hw_perf_event *hwc = &event->hw;
7496 u64 period = hwc->last_period;
7500 hwc->last_period = hwc->sample_period;
7503 old = val = local64_read(&hwc->period_left);
7507 nr = div64_u64(period + val, period);
7508 offset = nr * period;
7510 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7516 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7517 struct perf_sample_data *data,
7518 struct pt_regs *regs)
7520 struct hw_perf_event *hwc = &event->hw;
7524 overflow = perf_swevent_set_period(event);
7526 if (hwc->interrupts == MAX_INTERRUPTS)
7529 for (; overflow; overflow--) {
7530 if (__perf_event_overflow(event, throttle,
7533 * We inhibit the overflow from happening when
7534 * hwc->interrupts == MAX_INTERRUPTS.
7542 static void perf_swevent_event(struct perf_event *event, u64 nr,
7543 struct perf_sample_data *data,
7544 struct pt_regs *regs)
7546 struct hw_perf_event *hwc = &event->hw;
7548 local64_add(nr, &event->count);
7553 if (!is_sampling_event(event))
7556 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7558 return perf_swevent_overflow(event, 1, data, regs);
7560 data->period = event->hw.last_period;
7562 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7563 return perf_swevent_overflow(event, 1, data, regs);
7565 if (local64_add_negative(nr, &hwc->period_left))
7568 perf_swevent_overflow(event, 0, data, regs);
7571 static int perf_exclude_event(struct perf_event *event,
7572 struct pt_regs *regs)
7574 if (event->hw.state & PERF_HES_STOPPED)
7578 if (event->attr.exclude_user && user_mode(regs))
7581 if (event->attr.exclude_kernel && !user_mode(regs))
7588 static int perf_swevent_match(struct perf_event *event,
7589 enum perf_type_id type,
7591 struct perf_sample_data *data,
7592 struct pt_regs *regs)
7594 if (event->attr.type != type)
7597 if (event->attr.config != event_id)
7600 if (perf_exclude_event(event, regs))
7606 static inline u64 swevent_hash(u64 type, u32 event_id)
7608 u64 val = event_id | (type << 32);
7610 return hash_64(val, SWEVENT_HLIST_BITS);
7613 static inline struct hlist_head *
7614 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7616 u64 hash = swevent_hash(type, event_id);
7618 return &hlist->heads[hash];
7621 /* For the read side: events when they trigger */
7622 static inline struct hlist_head *
7623 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7625 struct swevent_hlist *hlist;
7627 hlist = rcu_dereference(swhash->swevent_hlist);
7631 return __find_swevent_head(hlist, type, event_id);
7634 /* For the event head insertion and removal in the hlist */
7635 static inline struct hlist_head *
7636 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7638 struct swevent_hlist *hlist;
7639 u32 event_id = event->attr.config;
7640 u64 type = event->attr.type;
7643 * Event scheduling is always serialized against hlist allocation
7644 * and release. Which makes the protected version suitable here.
7645 * The context lock guarantees that.
7647 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7648 lockdep_is_held(&event->ctx->lock));
7652 return __find_swevent_head(hlist, type, event_id);
7655 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7657 struct perf_sample_data *data,
7658 struct pt_regs *regs)
7660 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7661 struct perf_event *event;
7662 struct hlist_head *head;
7665 head = find_swevent_head_rcu(swhash, type, event_id);
7669 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7670 if (perf_swevent_match(event, type, event_id, data, regs))
7671 perf_swevent_event(event, nr, data, regs);
7677 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7679 int perf_swevent_get_recursion_context(void)
7681 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7683 return get_recursion_context(swhash->recursion);
7685 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7687 void perf_swevent_put_recursion_context(int rctx)
7689 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7691 put_recursion_context(swhash->recursion, rctx);
7694 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7696 struct perf_sample_data data;
7698 if (WARN_ON_ONCE(!regs))
7701 perf_sample_data_init(&data, addr, 0);
7702 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7705 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7709 preempt_disable_notrace();
7710 rctx = perf_swevent_get_recursion_context();
7711 if (unlikely(rctx < 0))
7714 ___perf_sw_event(event_id, nr, regs, addr);
7716 perf_swevent_put_recursion_context(rctx);
7718 preempt_enable_notrace();
7721 static void perf_swevent_read(struct perf_event *event)
7725 static int perf_swevent_add(struct perf_event *event, int flags)
7727 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7728 struct hw_perf_event *hwc = &event->hw;
7729 struct hlist_head *head;
7731 if (is_sampling_event(event)) {
7732 hwc->last_period = hwc->sample_period;
7733 perf_swevent_set_period(event);
7736 hwc->state = !(flags & PERF_EF_START);
7738 head = find_swevent_head(swhash, event);
7739 if (WARN_ON_ONCE(!head))
7742 hlist_add_head_rcu(&event->hlist_entry, head);
7743 perf_event_update_userpage(event);
7748 static void perf_swevent_del(struct perf_event *event, int flags)
7750 hlist_del_rcu(&event->hlist_entry);
7753 static void perf_swevent_start(struct perf_event *event, int flags)
7755 event->hw.state = 0;
7758 static void perf_swevent_stop(struct perf_event *event, int flags)
7760 event->hw.state = PERF_HES_STOPPED;
7763 /* Deref the hlist from the update side */
7764 static inline struct swevent_hlist *
7765 swevent_hlist_deref(struct swevent_htable *swhash)
7767 return rcu_dereference_protected(swhash->swevent_hlist,
7768 lockdep_is_held(&swhash->hlist_mutex));
7771 static void swevent_hlist_release(struct swevent_htable *swhash)
7773 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7778 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7779 kfree_rcu(hlist, rcu_head);
7782 static void swevent_hlist_put_cpu(int cpu)
7784 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7786 mutex_lock(&swhash->hlist_mutex);
7788 if (!--swhash->hlist_refcount)
7789 swevent_hlist_release(swhash);
7791 mutex_unlock(&swhash->hlist_mutex);
7794 static void swevent_hlist_put(void)
7798 for_each_possible_cpu(cpu)
7799 swevent_hlist_put_cpu(cpu);
7802 static int swevent_hlist_get_cpu(int cpu)
7804 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7807 mutex_lock(&swhash->hlist_mutex);
7808 if (!swevent_hlist_deref(swhash) &&
7809 cpumask_test_cpu(cpu, perf_online_mask)) {
7810 struct swevent_hlist *hlist;
7812 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7817 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7819 swhash->hlist_refcount++;
7821 mutex_unlock(&swhash->hlist_mutex);
7826 static int swevent_hlist_get(void)
7828 int err, cpu, failed_cpu;
7830 mutex_lock(&pmus_lock);
7831 for_each_possible_cpu(cpu) {
7832 err = swevent_hlist_get_cpu(cpu);
7838 mutex_unlock(&pmus_lock);
7841 for_each_possible_cpu(cpu) {
7842 if (cpu == failed_cpu)
7844 swevent_hlist_put_cpu(cpu);
7846 mutex_unlock(&pmus_lock);
7850 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7852 static void sw_perf_event_destroy(struct perf_event *event)
7854 u64 event_id = event->attr.config;
7856 WARN_ON(event->parent);
7858 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7859 swevent_hlist_put();
7862 static int perf_swevent_init(struct perf_event *event)
7864 u64 event_id = event->attr.config;
7866 if (event->attr.type != PERF_TYPE_SOFTWARE)
7870 * no branch sampling for software events
7872 if (has_branch_stack(event))
7876 case PERF_COUNT_SW_CPU_CLOCK:
7877 case PERF_COUNT_SW_TASK_CLOCK:
7884 if (event_id >= PERF_COUNT_SW_MAX)
7887 if (!event->parent) {
7890 err = swevent_hlist_get();
7894 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7895 event->destroy = sw_perf_event_destroy;
7901 static struct pmu perf_swevent = {
7902 .task_ctx_nr = perf_sw_context,
7904 .capabilities = PERF_PMU_CAP_NO_NMI,
7906 .event_init = perf_swevent_init,
7907 .add = perf_swevent_add,
7908 .del = perf_swevent_del,
7909 .start = perf_swevent_start,
7910 .stop = perf_swevent_stop,
7911 .read = perf_swevent_read,
7914 #ifdef CONFIG_EVENT_TRACING
7916 static int perf_tp_filter_match(struct perf_event *event,
7917 struct perf_sample_data *data)
7919 void *record = data->raw->frag.data;
7921 /* only top level events have filters set */
7923 event = event->parent;
7925 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7930 static int perf_tp_event_match(struct perf_event *event,
7931 struct perf_sample_data *data,
7932 struct pt_regs *regs)
7934 if (event->hw.state & PERF_HES_STOPPED)
7937 * All tracepoints are from kernel-space.
7939 if (event->attr.exclude_kernel)
7942 if (!perf_tp_filter_match(event, data))
7948 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7949 struct trace_event_call *call, u64 count,
7950 struct pt_regs *regs, struct hlist_head *head,
7951 struct task_struct *task)
7953 struct bpf_prog *prog = call->prog;
7956 *(struct pt_regs **)raw_data = regs;
7957 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7958 perf_swevent_put_recursion_context(rctx);
7962 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7965 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7967 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7968 struct pt_regs *regs, struct hlist_head *head, int rctx,
7969 struct task_struct *task, struct perf_event *event)
7971 struct perf_sample_data data;
7973 struct perf_raw_record raw = {
7980 perf_sample_data_init(&data, 0, 0);
7983 perf_trace_buf_update(record, event_type);
7985 /* Use the given event instead of the hlist */
7987 if (perf_tp_event_match(event, &data, regs))
7988 perf_swevent_event(event, count, &data, regs);
7990 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7991 if (perf_tp_event_match(event, &data, regs))
7992 perf_swevent_event(event, count, &data, regs);
7997 * If we got specified a target task, also iterate its context and
7998 * deliver this event there too.
8000 if (task && task != current) {
8001 struct perf_event_context *ctx;
8002 struct trace_entry *entry = record;
8005 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8009 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8010 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8012 if (event->attr.config != entry->type)
8014 if (perf_tp_event_match(event, &data, regs))
8015 perf_swevent_event(event, count, &data, regs);
8021 perf_swevent_put_recursion_context(rctx);
8023 EXPORT_SYMBOL_GPL(perf_tp_event);
8025 static void tp_perf_event_destroy(struct perf_event *event)
8027 perf_trace_destroy(event);
8030 static int perf_tp_event_init(struct perf_event *event)
8034 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8038 * no branch sampling for tracepoint events
8040 if (has_branch_stack(event))
8043 err = perf_trace_init(event);
8047 event->destroy = tp_perf_event_destroy;
8052 static struct pmu perf_tracepoint = {
8053 .task_ctx_nr = perf_sw_context,
8055 .event_init = perf_tp_event_init,
8056 .add = perf_trace_add,
8057 .del = perf_trace_del,
8058 .start = perf_swevent_start,
8059 .stop = perf_swevent_stop,
8060 .read = perf_swevent_read,
8063 static inline void perf_tp_register(void)
8065 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8068 static void perf_event_free_filter(struct perf_event *event)
8070 ftrace_profile_free_filter(event);
8073 #ifdef CONFIG_BPF_SYSCALL
8074 static void bpf_overflow_handler(struct perf_event *event,
8075 struct perf_sample_data *data,
8076 struct pt_regs *regs)
8078 struct bpf_perf_event_data_kern ctx = {
8085 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8088 ret = BPF_PROG_RUN(event->prog, &ctx);
8091 __this_cpu_dec(bpf_prog_active);
8096 event->orig_overflow_handler(event, data, regs);
8099 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8101 struct bpf_prog *prog;
8103 if (event->overflow_handler_context)
8104 /* hw breakpoint or kernel counter */
8110 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8112 return PTR_ERR(prog);
8115 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8116 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8120 static void perf_event_free_bpf_handler(struct perf_event *event)
8122 struct bpf_prog *prog = event->prog;
8127 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8132 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8136 static void perf_event_free_bpf_handler(struct perf_event *event)
8141 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8143 bool is_kprobe, is_tracepoint, is_syscall_tp;
8144 struct bpf_prog *prog;
8146 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8147 return perf_event_set_bpf_handler(event, prog_fd);
8149 if (event->tp_event->prog)
8152 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8153 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8154 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8155 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8156 /* bpf programs can only be attached to u/kprobe or tracepoint */
8159 prog = bpf_prog_get(prog_fd);
8161 return PTR_ERR(prog);
8163 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8164 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8165 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8166 /* valid fd, but invalid bpf program type */
8171 if (is_tracepoint || is_syscall_tp) {
8172 int off = trace_event_get_offsets(event->tp_event);
8174 if (prog->aux->max_ctx_offset > off) {
8179 event->tp_event->prog = prog;
8180 event->tp_event->bpf_prog_owner = event;
8185 static void perf_event_free_bpf_prog(struct perf_event *event)
8187 struct bpf_prog *prog;
8189 perf_event_free_bpf_handler(event);
8191 if (!event->tp_event)
8194 prog = event->tp_event->prog;
8195 if (prog && event->tp_event->bpf_prog_owner == event) {
8196 event->tp_event->prog = NULL;
8203 static inline void perf_tp_register(void)
8207 static void perf_event_free_filter(struct perf_event *event)
8211 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8216 static void perf_event_free_bpf_prog(struct perf_event *event)
8219 #endif /* CONFIG_EVENT_TRACING */
8221 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8222 void perf_bp_event(struct perf_event *bp, void *data)
8224 struct perf_sample_data sample;
8225 struct pt_regs *regs = data;
8227 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8229 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8230 perf_swevent_event(bp, 1, &sample, regs);
8235 * Allocate a new address filter
8237 static struct perf_addr_filter *
8238 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8240 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8241 struct perf_addr_filter *filter;
8243 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8247 INIT_LIST_HEAD(&filter->entry);
8248 list_add_tail(&filter->entry, filters);
8253 static void free_filters_list(struct list_head *filters)
8255 struct perf_addr_filter *filter, *iter;
8257 list_for_each_entry_safe(filter, iter, filters, entry) {
8259 iput(filter->inode);
8260 list_del(&filter->entry);
8266 * Free existing address filters and optionally install new ones
8268 static void perf_addr_filters_splice(struct perf_event *event,
8269 struct list_head *head)
8271 unsigned long flags;
8274 if (!has_addr_filter(event))
8277 /* don't bother with children, they don't have their own filters */
8281 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8283 list_splice_init(&event->addr_filters.list, &list);
8285 list_splice(head, &event->addr_filters.list);
8287 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8289 free_filters_list(&list);
8293 * Scan through mm's vmas and see if one of them matches the
8294 * @filter; if so, adjust filter's address range.
8295 * Called with mm::mmap_sem down for reading.
8297 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8298 struct mm_struct *mm)
8300 struct vm_area_struct *vma;
8302 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8303 struct file *file = vma->vm_file;
8304 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8305 unsigned long vma_size = vma->vm_end - vma->vm_start;
8310 if (!perf_addr_filter_match(filter, file, off, vma_size))
8313 return vma->vm_start;
8320 * Update event's address range filters based on the
8321 * task's existing mappings, if any.
8323 static void perf_event_addr_filters_apply(struct perf_event *event)
8325 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8326 struct task_struct *task = READ_ONCE(event->ctx->task);
8327 struct perf_addr_filter *filter;
8328 struct mm_struct *mm = NULL;
8329 unsigned int count = 0;
8330 unsigned long flags;
8333 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8334 * will stop on the parent's child_mutex that our caller is also holding
8336 if (task == TASK_TOMBSTONE)
8339 if (!ifh->nr_file_filters)
8342 mm = get_task_mm(event->ctx->task);
8346 down_read(&mm->mmap_sem);
8348 raw_spin_lock_irqsave(&ifh->lock, flags);
8349 list_for_each_entry(filter, &ifh->list, entry) {
8350 event->addr_filters_offs[count] = 0;
8353 * Adjust base offset if the filter is associated to a binary
8354 * that needs to be mapped:
8357 event->addr_filters_offs[count] =
8358 perf_addr_filter_apply(filter, mm);
8363 event->addr_filters_gen++;
8364 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8366 up_read(&mm->mmap_sem);
8371 perf_event_stop(event, 1);
8375 * Address range filtering: limiting the data to certain
8376 * instruction address ranges. Filters are ioctl()ed to us from
8377 * userspace as ascii strings.
8379 * Filter string format:
8382 * where ACTION is one of the
8383 * * "filter": limit the trace to this region
8384 * * "start": start tracing from this address
8385 * * "stop": stop tracing at this address/region;
8387 * * for kernel addresses: <start address>[/<size>]
8388 * * for object files: <start address>[/<size>]@</path/to/object/file>
8390 * if <size> is not specified, the range is treated as a single address.
8404 IF_STATE_ACTION = 0,
8409 static const match_table_t if_tokens = {
8410 { IF_ACT_FILTER, "filter" },
8411 { IF_ACT_START, "start" },
8412 { IF_ACT_STOP, "stop" },
8413 { IF_SRC_FILE, "%u/%u@%s" },
8414 { IF_SRC_KERNEL, "%u/%u" },
8415 { IF_SRC_FILEADDR, "%u@%s" },
8416 { IF_SRC_KERNELADDR, "%u" },
8417 { IF_ACT_NONE, NULL },
8421 * Address filter string parser
8424 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8425 struct list_head *filters)
8427 struct perf_addr_filter *filter = NULL;
8428 char *start, *orig, *filename = NULL;
8430 substring_t args[MAX_OPT_ARGS];
8431 int state = IF_STATE_ACTION, token;
8432 unsigned int kernel = 0;
8435 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8439 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8445 /* filter definition begins */
8446 if (state == IF_STATE_ACTION) {
8447 filter = perf_addr_filter_new(event, filters);
8452 token = match_token(start, if_tokens, args);
8459 if (state != IF_STATE_ACTION)
8462 state = IF_STATE_SOURCE;
8465 case IF_SRC_KERNELADDR:
8469 case IF_SRC_FILEADDR:
8471 if (state != IF_STATE_SOURCE)
8474 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8478 ret = kstrtoul(args[0].from, 0, &filter->offset);
8482 if (filter->range) {
8484 ret = kstrtoul(args[1].from, 0, &filter->size);
8489 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8490 int fpos = filter->range ? 2 : 1;
8492 filename = match_strdup(&args[fpos]);
8499 state = IF_STATE_END;
8507 * Filter definition is fully parsed, validate and install it.
8508 * Make sure that it doesn't contradict itself or the event's
8511 if (state == IF_STATE_END) {
8513 if (kernel && event->attr.exclude_kernel)
8521 * For now, we only support file-based filters
8522 * in per-task events; doing so for CPU-wide
8523 * events requires additional context switching
8524 * trickery, since same object code will be
8525 * mapped at different virtual addresses in
8526 * different processes.
8529 if (!event->ctx->task)
8530 goto fail_free_name;
8532 /* look up the path and grab its inode */
8533 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8535 goto fail_free_name;
8537 filter->inode = igrab(d_inode(path.dentry));
8543 if (!filter->inode ||
8544 !S_ISREG(filter->inode->i_mode))
8545 /* free_filters_list() will iput() */
8548 event->addr_filters.nr_file_filters++;
8551 /* ready to consume more filters */
8552 state = IF_STATE_ACTION;
8557 if (state != IF_STATE_ACTION)
8567 free_filters_list(filters);
8574 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8580 * Since this is called in perf_ioctl() path, we're already holding
8583 lockdep_assert_held(&event->ctx->mutex);
8585 if (WARN_ON_ONCE(event->parent))
8588 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8590 goto fail_clear_files;
8592 ret = event->pmu->addr_filters_validate(&filters);
8594 goto fail_free_filters;
8596 /* remove existing filters, if any */
8597 perf_addr_filters_splice(event, &filters);
8599 /* install new filters */
8600 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8605 free_filters_list(&filters);
8608 event->addr_filters.nr_file_filters = 0;
8613 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8618 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8619 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8620 !has_addr_filter(event))
8623 filter_str = strndup_user(arg, PAGE_SIZE);
8624 if (IS_ERR(filter_str))
8625 return PTR_ERR(filter_str);
8627 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8628 event->attr.type == PERF_TYPE_TRACEPOINT)
8629 ret = ftrace_profile_set_filter(event, event->attr.config,
8631 else if (has_addr_filter(event))
8632 ret = perf_event_set_addr_filter(event, filter_str);
8639 * hrtimer based swevent callback
8642 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8644 enum hrtimer_restart ret = HRTIMER_RESTART;
8645 struct perf_sample_data data;
8646 struct pt_regs *regs;
8647 struct perf_event *event;
8650 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8652 if (event->state != PERF_EVENT_STATE_ACTIVE)
8653 return HRTIMER_NORESTART;
8655 event->pmu->read(event);
8657 perf_sample_data_init(&data, 0, event->hw.last_period);
8658 regs = get_irq_regs();
8660 if (regs && !perf_exclude_event(event, regs)) {
8661 if (!(event->attr.exclude_idle && is_idle_task(current)))
8662 if (__perf_event_overflow(event, 1, &data, regs))
8663 ret = HRTIMER_NORESTART;
8666 period = max_t(u64, 10000, event->hw.sample_period);
8667 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8672 static void perf_swevent_start_hrtimer(struct perf_event *event)
8674 struct hw_perf_event *hwc = &event->hw;
8677 if (!is_sampling_event(event))
8680 period = local64_read(&hwc->period_left);
8685 local64_set(&hwc->period_left, 0);
8687 period = max_t(u64, 10000, hwc->sample_period);
8689 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8690 HRTIMER_MODE_REL_PINNED);
8693 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8695 struct hw_perf_event *hwc = &event->hw;
8697 if (is_sampling_event(event)) {
8698 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8699 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8701 hrtimer_cancel(&hwc->hrtimer);
8705 static void perf_swevent_init_hrtimer(struct perf_event *event)
8707 struct hw_perf_event *hwc = &event->hw;
8709 if (!is_sampling_event(event))
8712 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8713 hwc->hrtimer.function = perf_swevent_hrtimer;
8716 * Since hrtimers have a fixed rate, we can do a static freq->period
8717 * mapping and avoid the whole period adjust feedback stuff.
8719 if (event->attr.freq) {
8720 long freq = event->attr.sample_freq;
8722 event->attr.sample_period = NSEC_PER_SEC / freq;
8723 hwc->sample_period = event->attr.sample_period;
8724 local64_set(&hwc->period_left, hwc->sample_period);
8725 hwc->last_period = hwc->sample_period;
8726 event->attr.freq = 0;
8731 * Software event: cpu wall time clock
8734 static void cpu_clock_event_update(struct perf_event *event)
8739 now = local_clock();
8740 prev = local64_xchg(&event->hw.prev_count, now);
8741 local64_add(now - prev, &event->count);
8744 static void cpu_clock_event_start(struct perf_event *event, int flags)
8746 local64_set(&event->hw.prev_count, local_clock());
8747 perf_swevent_start_hrtimer(event);
8750 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8752 perf_swevent_cancel_hrtimer(event);
8753 cpu_clock_event_update(event);
8756 static int cpu_clock_event_add(struct perf_event *event, int flags)
8758 if (flags & PERF_EF_START)
8759 cpu_clock_event_start(event, flags);
8760 perf_event_update_userpage(event);
8765 static void cpu_clock_event_del(struct perf_event *event, int flags)
8767 cpu_clock_event_stop(event, flags);
8770 static void cpu_clock_event_read(struct perf_event *event)
8772 cpu_clock_event_update(event);
8775 static int cpu_clock_event_init(struct perf_event *event)
8777 if (event->attr.type != PERF_TYPE_SOFTWARE)
8780 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8784 * no branch sampling for software events
8786 if (has_branch_stack(event))
8789 perf_swevent_init_hrtimer(event);
8794 static struct pmu perf_cpu_clock = {
8795 .task_ctx_nr = perf_sw_context,
8797 .capabilities = PERF_PMU_CAP_NO_NMI,
8799 .event_init = cpu_clock_event_init,
8800 .add = cpu_clock_event_add,
8801 .del = cpu_clock_event_del,
8802 .start = cpu_clock_event_start,
8803 .stop = cpu_clock_event_stop,
8804 .read = cpu_clock_event_read,
8808 * Software event: task time clock
8811 static void task_clock_event_update(struct perf_event *event, u64 now)
8816 prev = local64_xchg(&event->hw.prev_count, now);
8818 local64_add(delta, &event->count);
8821 static void task_clock_event_start(struct perf_event *event, int flags)
8823 local64_set(&event->hw.prev_count, event->ctx->time);
8824 perf_swevent_start_hrtimer(event);
8827 static void task_clock_event_stop(struct perf_event *event, int flags)
8829 perf_swevent_cancel_hrtimer(event);
8830 task_clock_event_update(event, event->ctx->time);
8833 static int task_clock_event_add(struct perf_event *event, int flags)
8835 if (flags & PERF_EF_START)
8836 task_clock_event_start(event, flags);
8837 perf_event_update_userpage(event);
8842 static void task_clock_event_del(struct perf_event *event, int flags)
8844 task_clock_event_stop(event, PERF_EF_UPDATE);
8847 static void task_clock_event_read(struct perf_event *event)
8849 u64 now = perf_clock();
8850 u64 delta = now - event->ctx->timestamp;
8851 u64 time = event->ctx->time + delta;
8853 task_clock_event_update(event, time);
8856 static int task_clock_event_init(struct perf_event *event)
8858 if (event->attr.type != PERF_TYPE_SOFTWARE)
8861 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8865 * no branch sampling for software events
8867 if (has_branch_stack(event))
8870 perf_swevent_init_hrtimer(event);
8875 static struct pmu perf_task_clock = {
8876 .task_ctx_nr = perf_sw_context,
8878 .capabilities = PERF_PMU_CAP_NO_NMI,
8880 .event_init = task_clock_event_init,
8881 .add = task_clock_event_add,
8882 .del = task_clock_event_del,
8883 .start = task_clock_event_start,
8884 .stop = task_clock_event_stop,
8885 .read = task_clock_event_read,
8888 static void perf_pmu_nop_void(struct pmu *pmu)
8892 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8896 static int perf_pmu_nop_int(struct pmu *pmu)
8901 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8903 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8905 __this_cpu_write(nop_txn_flags, flags);
8907 if (flags & ~PERF_PMU_TXN_ADD)
8910 perf_pmu_disable(pmu);
8913 static int perf_pmu_commit_txn(struct pmu *pmu)
8915 unsigned int flags = __this_cpu_read(nop_txn_flags);
8917 __this_cpu_write(nop_txn_flags, 0);
8919 if (flags & ~PERF_PMU_TXN_ADD)
8922 perf_pmu_enable(pmu);
8926 static void perf_pmu_cancel_txn(struct pmu *pmu)
8928 unsigned int flags = __this_cpu_read(nop_txn_flags);
8930 __this_cpu_write(nop_txn_flags, 0);
8932 if (flags & ~PERF_PMU_TXN_ADD)
8935 perf_pmu_enable(pmu);
8938 static int perf_event_idx_default(struct perf_event *event)
8944 * Ensures all contexts with the same task_ctx_nr have the same
8945 * pmu_cpu_context too.
8947 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8954 list_for_each_entry(pmu, &pmus, entry) {
8955 if (pmu->task_ctx_nr == ctxn)
8956 return pmu->pmu_cpu_context;
8962 static void free_pmu_context(struct pmu *pmu)
8965 * Static contexts such as perf_sw_context have a global lifetime
8966 * and may be shared between different PMUs. Avoid freeing them
8967 * when a single PMU is going away.
8969 if (pmu->task_ctx_nr > perf_invalid_context)
8972 mutex_lock(&pmus_lock);
8973 free_percpu(pmu->pmu_cpu_context);
8974 mutex_unlock(&pmus_lock);
8978 * Let userspace know that this PMU supports address range filtering:
8980 static ssize_t nr_addr_filters_show(struct device *dev,
8981 struct device_attribute *attr,
8984 struct pmu *pmu = dev_get_drvdata(dev);
8986 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8988 DEVICE_ATTR_RO(nr_addr_filters);
8990 static struct idr pmu_idr;
8993 type_show(struct device *dev, struct device_attribute *attr, char *page)
8995 struct pmu *pmu = dev_get_drvdata(dev);
8997 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8999 static DEVICE_ATTR_RO(type);
9002 perf_event_mux_interval_ms_show(struct device *dev,
9003 struct device_attribute *attr,
9006 struct pmu *pmu = dev_get_drvdata(dev);
9008 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9011 static DEFINE_MUTEX(mux_interval_mutex);
9014 perf_event_mux_interval_ms_store(struct device *dev,
9015 struct device_attribute *attr,
9016 const char *buf, size_t count)
9018 struct pmu *pmu = dev_get_drvdata(dev);
9019 int timer, cpu, ret;
9021 ret = kstrtoint(buf, 0, &timer);
9028 /* same value, noting to do */
9029 if (timer == pmu->hrtimer_interval_ms)
9032 mutex_lock(&mux_interval_mutex);
9033 pmu->hrtimer_interval_ms = timer;
9035 /* update all cpuctx for this PMU */
9037 for_each_online_cpu(cpu) {
9038 struct perf_cpu_context *cpuctx;
9039 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9040 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9042 cpu_function_call(cpu,
9043 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9046 mutex_unlock(&mux_interval_mutex);
9050 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9052 static struct attribute *pmu_dev_attrs[] = {
9053 &dev_attr_type.attr,
9054 &dev_attr_perf_event_mux_interval_ms.attr,
9057 ATTRIBUTE_GROUPS(pmu_dev);
9059 static int pmu_bus_running;
9060 static struct bus_type pmu_bus = {
9061 .name = "event_source",
9062 .dev_groups = pmu_dev_groups,
9065 static void pmu_dev_release(struct device *dev)
9070 static int pmu_dev_alloc(struct pmu *pmu)
9074 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9078 pmu->dev->groups = pmu->attr_groups;
9079 device_initialize(pmu->dev);
9080 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9084 dev_set_drvdata(pmu->dev, pmu);
9085 pmu->dev->bus = &pmu_bus;
9086 pmu->dev->release = pmu_dev_release;
9087 ret = device_add(pmu->dev);
9091 /* For PMUs with address filters, throw in an extra attribute: */
9092 if (pmu->nr_addr_filters)
9093 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9102 device_del(pmu->dev);
9105 put_device(pmu->dev);
9109 static struct lock_class_key cpuctx_mutex;
9110 static struct lock_class_key cpuctx_lock;
9112 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9116 mutex_lock(&pmus_lock);
9118 pmu->pmu_disable_count = alloc_percpu(int);
9119 if (!pmu->pmu_disable_count)
9128 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9136 if (pmu_bus_running) {
9137 ret = pmu_dev_alloc(pmu);
9143 if (pmu->task_ctx_nr == perf_hw_context) {
9144 static int hw_context_taken = 0;
9147 * Other than systems with heterogeneous CPUs, it never makes
9148 * sense for two PMUs to share perf_hw_context. PMUs which are
9149 * uncore must use perf_invalid_context.
9151 if (WARN_ON_ONCE(hw_context_taken &&
9152 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9153 pmu->task_ctx_nr = perf_invalid_context;
9155 hw_context_taken = 1;
9158 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9159 if (pmu->pmu_cpu_context)
9160 goto got_cpu_context;
9163 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9164 if (!pmu->pmu_cpu_context)
9167 for_each_possible_cpu(cpu) {
9168 struct perf_cpu_context *cpuctx;
9170 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9171 __perf_event_init_context(&cpuctx->ctx);
9172 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9173 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9174 cpuctx->ctx.pmu = pmu;
9175 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9177 __perf_mux_hrtimer_init(cpuctx, cpu);
9181 if (!pmu->start_txn) {
9182 if (pmu->pmu_enable) {
9184 * If we have pmu_enable/pmu_disable calls, install
9185 * transaction stubs that use that to try and batch
9186 * hardware accesses.
9188 pmu->start_txn = perf_pmu_start_txn;
9189 pmu->commit_txn = perf_pmu_commit_txn;
9190 pmu->cancel_txn = perf_pmu_cancel_txn;
9192 pmu->start_txn = perf_pmu_nop_txn;
9193 pmu->commit_txn = perf_pmu_nop_int;
9194 pmu->cancel_txn = perf_pmu_nop_void;
9198 if (!pmu->pmu_enable) {
9199 pmu->pmu_enable = perf_pmu_nop_void;
9200 pmu->pmu_disable = perf_pmu_nop_void;
9203 if (!pmu->event_idx)
9204 pmu->event_idx = perf_event_idx_default;
9206 list_add_rcu(&pmu->entry, &pmus);
9207 atomic_set(&pmu->exclusive_cnt, 0);
9210 mutex_unlock(&pmus_lock);
9215 device_del(pmu->dev);
9216 put_device(pmu->dev);
9219 if (pmu->type >= PERF_TYPE_MAX)
9220 idr_remove(&pmu_idr, pmu->type);
9223 free_percpu(pmu->pmu_disable_count);
9226 EXPORT_SYMBOL_GPL(perf_pmu_register);
9228 void perf_pmu_unregister(struct pmu *pmu)
9232 mutex_lock(&pmus_lock);
9233 remove_device = pmu_bus_running;
9234 list_del_rcu(&pmu->entry);
9235 mutex_unlock(&pmus_lock);
9238 * We dereference the pmu list under both SRCU and regular RCU, so
9239 * synchronize against both of those.
9241 synchronize_srcu(&pmus_srcu);
9244 free_percpu(pmu->pmu_disable_count);
9245 if (pmu->type >= PERF_TYPE_MAX)
9246 idr_remove(&pmu_idr, pmu->type);
9247 if (remove_device) {
9248 if (pmu->nr_addr_filters)
9249 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9250 device_del(pmu->dev);
9251 put_device(pmu->dev);
9253 free_pmu_context(pmu);
9255 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9257 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9259 struct perf_event_context *ctx = NULL;
9262 if (!try_module_get(pmu->module))
9265 if (event->group_leader != event) {
9267 * This ctx->mutex can nest when we're called through
9268 * inheritance. See the perf_event_ctx_lock_nested() comment.
9270 ctx = perf_event_ctx_lock_nested(event->group_leader,
9271 SINGLE_DEPTH_NESTING);
9276 ret = pmu->event_init(event);
9279 perf_event_ctx_unlock(event->group_leader, ctx);
9282 module_put(pmu->module);
9287 static struct pmu *perf_init_event(struct perf_event *event)
9293 idx = srcu_read_lock(&pmus_srcu);
9295 /* Try parent's PMU first: */
9296 if (event->parent && event->parent->pmu) {
9297 pmu = event->parent->pmu;
9298 ret = perf_try_init_event(pmu, event);
9304 pmu = idr_find(&pmu_idr, event->attr.type);
9307 ret = perf_try_init_event(pmu, event);
9313 list_for_each_entry_rcu(pmu, &pmus, entry) {
9314 ret = perf_try_init_event(pmu, event);
9318 if (ret != -ENOENT) {
9323 pmu = ERR_PTR(-ENOENT);
9325 srcu_read_unlock(&pmus_srcu, idx);
9330 static void attach_sb_event(struct perf_event *event)
9332 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9334 raw_spin_lock(&pel->lock);
9335 list_add_rcu(&event->sb_list, &pel->list);
9336 raw_spin_unlock(&pel->lock);
9340 * We keep a list of all !task (and therefore per-cpu) events
9341 * that need to receive side-band records.
9343 * This avoids having to scan all the various PMU per-cpu contexts
9346 static void account_pmu_sb_event(struct perf_event *event)
9348 if (is_sb_event(event))
9349 attach_sb_event(event);
9352 static void account_event_cpu(struct perf_event *event, int cpu)
9357 if (is_cgroup_event(event))
9358 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9361 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9362 static void account_freq_event_nohz(void)
9364 #ifdef CONFIG_NO_HZ_FULL
9365 /* Lock so we don't race with concurrent unaccount */
9366 spin_lock(&nr_freq_lock);
9367 if (atomic_inc_return(&nr_freq_events) == 1)
9368 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9369 spin_unlock(&nr_freq_lock);
9373 static void account_freq_event(void)
9375 if (tick_nohz_full_enabled())
9376 account_freq_event_nohz();
9378 atomic_inc(&nr_freq_events);
9382 static void account_event(struct perf_event *event)
9389 if (event->attach_state & PERF_ATTACH_TASK)
9391 if (event->attr.mmap || event->attr.mmap_data)
9392 atomic_inc(&nr_mmap_events);
9393 if (event->attr.comm)
9394 atomic_inc(&nr_comm_events);
9395 if (event->attr.namespaces)
9396 atomic_inc(&nr_namespaces_events);
9397 if (event->attr.task)
9398 atomic_inc(&nr_task_events);
9399 if (event->attr.freq)
9400 account_freq_event();
9401 if (event->attr.context_switch) {
9402 atomic_inc(&nr_switch_events);
9405 if (has_branch_stack(event))
9407 if (is_cgroup_event(event))
9411 if (atomic_inc_not_zero(&perf_sched_count))
9414 mutex_lock(&perf_sched_mutex);
9415 if (!atomic_read(&perf_sched_count)) {
9416 static_branch_enable(&perf_sched_events);
9418 * Guarantee that all CPUs observe they key change and
9419 * call the perf scheduling hooks before proceeding to
9420 * install events that need them.
9422 synchronize_sched();
9425 * Now that we have waited for the sync_sched(), allow further
9426 * increments to by-pass the mutex.
9428 atomic_inc(&perf_sched_count);
9429 mutex_unlock(&perf_sched_mutex);
9433 account_event_cpu(event, event->cpu);
9435 account_pmu_sb_event(event);
9439 * Allocate and initialize a event structure
9441 static struct perf_event *
9442 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9443 struct task_struct *task,
9444 struct perf_event *group_leader,
9445 struct perf_event *parent_event,
9446 perf_overflow_handler_t overflow_handler,
9447 void *context, int cgroup_fd)
9450 struct perf_event *event;
9451 struct hw_perf_event *hwc;
9454 if ((unsigned)cpu >= nr_cpu_ids) {
9455 if (!task || cpu != -1)
9456 return ERR_PTR(-EINVAL);
9459 event = kzalloc(sizeof(*event), GFP_KERNEL);
9461 return ERR_PTR(-ENOMEM);
9464 * Single events are their own group leaders, with an
9465 * empty sibling list:
9468 group_leader = event;
9470 mutex_init(&event->child_mutex);
9471 INIT_LIST_HEAD(&event->child_list);
9473 INIT_LIST_HEAD(&event->group_entry);
9474 INIT_LIST_HEAD(&event->event_entry);
9475 INIT_LIST_HEAD(&event->sibling_list);
9476 INIT_LIST_HEAD(&event->rb_entry);
9477 INIT_LIST_HEAD(&event->active_entry);
9478 INIT_LIST_HEAD(&event->addr_filters.list);
9479 INIT_HLIST_NODE(&event->hlist_entry);
9482 init_waitqueue_head(&event->waitq);
9483 init_irq_work(&event->pending, perf_pending_event);
9485 mutex_init(&event->mmap_mutex);
9486 raw_spin_lock_init(&event->addr_filters.lock);
9488 atomic_long_set(&event->refcount, 1);
9490 event->attr = *attr;
9491 event->group_leader = group_leader;
9495 event->parent = parent_event;
9497 event->ns = get_pid_ns(task_active_pid_ns(current));
9498 event->id = atomic64_inc_return(&perf_event_id);
9500 event->state = PERF_EVENT_STATE_INACTIVE;
9503 event->attach_state = PERF_ATTACH_TASK;
9505 * XXX pmu::event_init needs to know what task to account to
9506 * and we cannot use the ctx information because we need the
9507 * pmu before we get a ctx.
9509 event->hw.target = task;
9512 event->clock = &local_clock;
9514 event->clock = parent_event->clock;
9516 if (!overflow_handler && parent_event) {
9517 overflow_handler = parent_event->overflow_handler;
9518 context = parent_event->overflow_handler_context;
9519 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9520 if (overflow_handler == bpf_overflow_handler) {
9521 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9524 err = PTR_ERR(prog);
9528 event->orig_overflow_handler =
9529 parent_event->orig_overflow_handler;
9534 if (overflow_handler) {
9535 event->overflow_handler = overflow_handler;
9536 event->overflow_handler_context = context;
9537 } else if (is_write_backward(event)){
9538 event->overflow_handler = perf_event_output_backward;
9539 event->overflow_handler_context = NULL;
9541 event->overflow_handler = perf_event_output_forward;
9542 event->overflow_handler_context = NULL;
9545 perf_event__state_init(event);
9550 hwc->sample_period = attr->sample_period;
9551 if (attr->freq && attr->sample_freq)
9552 hwc->sample_period = 1;
9553 hwc->last_period = hwc->sample_period;
9555 local64_set(&hwc->period_left, hwc->sample_period);
9558 * We currently do not support PERF_SAMPLE_READ on inherited events.
9559 * See perf_output_read().
9561 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9564 if (!has_branch_stack(event))
9565 event->attr.branch_sample_type = 0;
9567 if (cgroup_fd != -1) {
9568 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9573 pmu = perf_init_event(event);
9579 err = exclusive_event_init(event);
9583 if (has_addr_filter(event)) {
9584 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9585 sizeof(unsigned long),
9587 if (!event->addr_filters_offs) {
9592 /* force hw sync on the address filters */
9593 event->addr_filters_gen = 1;
9596 if (!event->parent) {
9597 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9598 err = get_callchain_buffers(attr->sample_max_stack);
9600 goto err_addr_filters;
9604 /* symmetric to unaccount_event() in _free_event() */
9605 account_event(event);
9610 kfree(event->addr_filters_offs);
9613 exclusive_event_destroy(event);
9617 event->destroy(event);
9618 module_put(pmu->module);
9620 if (is_cgroup_event(event))
9621 perf_detach_cgroup(event);
9623 put_pid_ns(event->ns);
9626 return ERR_PTR(err);
9629 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9630 struct perf_event_attr *attr)
9635 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9639 * zero the full structure, so that a short copy will be nice.
9641 memset(attr, 0, sizeof(*attr));
9643 ret = get_user(size, &uattr->size);
9647 if (size > PAGE_SIZE) /* silly large */
9650 if (!size) /* abi compat */
9651 size = PERF_ATTR_SIZE_VER0;
9653 if (size < PERF_ATTR_SIZE_VER0)
9657 * If we're handed a bigger struct than we know of,
9658 * ensure all the unknown bits are 0 - i.e. new
9659 * user-space does not rely on any kernel feature
9660 * extensions we dont know about yet.
9662 if (size > sizeof(*attr)) {
9663 unsigned char __user *addr;
9664 unsigned char __user *end;
9667 addr = (void __user *)uattr + sizeof(*attr);
9668 end = (void __user *)uattr + size;
9670 for (; addr < end; addr++) {
9671 ret = get_user(val, addr);
9677 size = sizeof(*attr);
9680 ret = copy_from_user(attr, uattr, size);
9686 if (attr->__reserved_1)
9689 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9692 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9695 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9696 u64 mask = attr->branch_sample_type;
9698 /* only using defined bits */
9699 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9702 /* at least one branch bit must be set */
9703 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9706 /* propagate priv level, when not set for branch */
9707 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9709 /* exclude_kernel checked on syscall entry */
9710 if (!attr->exclude_kernel)
9711 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9713 if (!attr->exclude_user)
9714 mask |= PERF_SAMPLE_BRANCH_USER;
9716 if (!attr->exclude_hv)
9717 mask |= PERF_SAMPLE_BRANCH_HV;
9719 * adjust user setting (for HW filter setup)
9721 attr->branch_sample_type = mask;
9723 /* privileged levels capture (kernel, hv): check permissions */
9724 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9725 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9729 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9730 ret = perf_reg_validate(attr->sample_regs_user);
9735 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9736 if (!arch_perf_have_user_stack_dump())
9740 * We have __u32 type for the size, but so far
9741 * we can only use __u16 as maximum due to the
9742 * __u16 sample size limit.
9744 if (attr->sample_stack_user >= USHRT_MAX)
9746 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9750 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9751 ret = perf_reg_validate(attr->sample_regs_intr);
9756 put_user(sizeof(*attr), &uattr->size);
9762 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9764 struct ring_buffer *rb = NULL;
9770 /* don't allow circular references */
9771 if (event == output_event)
9775 * Don't allow cross-cpu buffers
9777 if (output_event->cpu != event->cpu)
9781 * If its not a per-cpu rb, it must be the same task.
9783 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9787 * Mixing clocks in the same buffer is trouble you don't need.
9789 if (output_event->clock != event->clock)
9793 * Either writing ring buffer from beginning or from end.
9794 * Mixing is not allowed.
9796 if (is_write_backward(output_event) != is_write_backward(event))
9800 * If both events generate aux data, they must be on the same PMU
9802 if (has_aux(event) && has_aux(output_event) &&
9803 event->pmu != output_event->pmu)
9807 mutex_lock(&event->mmap_mutex);
9808 /* Can't redirect output if we've got an active mmap() */
9809 if (atomic_read(&event->mmap_count))
9813 /* get the rb we want to redirect to */
9814 rb = ring_buffer_get(output_event);
9819 ring_buffer_attach(event, rb);
9823 mutex_unlock(&event->mmap_mutex);
9829 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9835 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9838 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9840 bool nmi_safe = false;
9843 case CLOCK_MONOTONIC:
9844 event->clock = &ktime_get_mono_fast_ns;
9848 case CLOCK_MONOTONIC_RAW:
9849 event->clock = &ktime_get_raw_fast_ns;
9853 case CLOCK_REALTIME:
9854 event->clock = &ktime_get_real_ns;
9857 case CLOCK_BOOTTIME:
9858 event->clock = &ktime_get_boot_ns;
9862 event->clock = &ktime_get_tai_ns;
9869 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9876 * Variation on perf_event_ctx_lock_nested(), except we take two context
9879 static struct perf_event_context *
9880 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9881 struct perf_event_context *ctx)
9883 struct perf_event_context *gctx;
9887 gctx = READ_ONCE(group_leader->ctx);
9888 if (!atomic_inc_not_zero(&gctx->refcount)) {
9894 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9896 if (group_leader->ctx != gctx) {
9897 mutex_unlock(&ctx->mutex);
9898 mutex_unlock(&gctx->mutex);
9907 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9909 * @attr_uptr: event_id type attributes for monitoring/sampling
9912 * @group_fd: group leader event fd
9914 SYSCALL_DEFINE5(perf_event_open,
9915 struct perf_event_attr __user *, attr_uptr,
9916 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9918 struct perf_event *group_leader = NULL, *output_event = NULL;
9919 struct perf_event *event, *sibling;
9920 struct perf_event_attr attr;
9921 struct perf_event_context *ctx, *uninitialized_var(gctx);
9922 struct file *event_file = NULL;
9923 struct fd group = {NULL, 0};
9924 struct task_struct *task = NULL;
9929 int f_flags = O_RDWR;
9932 /* for future expandability... */
9933 if (flags & ~PERF_FLAG_ALL)
9936 err = perf_copy_attr(attr_uptr, &attr);
9940 if (!attr.exclude_kernel) {
9941 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9945 if (attr.namespaces) {
9946 if (!capable(CAP_SYS_ADMIN))
9951 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9954 if (attr.sample_period & (1ULL << 63))
9958 /* Only privileged users can get physical addresses */
9959 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
9960 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9963 if (!attr.sample_max_stack)
9964 attr.sample_max_stack = sysctl_perf_event_max_stack;
9967 * In cgroup mode, the pid argument is used to pass the fd
9968 * opened to the cgroup directory in cgroupfs. The cpu argument
9969 * designates the cpu on which to monitor threads from that
9972 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9975 if (flags & PERF_FLAG_FD_CLOEXEC)
9976 f_flags |= O_CLOEXEC;
9978 event_fd = get_unused_fd_flags(f_flags);
9982 if (group_fd != -1) {
9983 err = perf_fget_light(group_fd, &group);
9986 group_leader = group.file->private_data;
9987 if (flags & PERF_FLAG_FD_OUTPUT)
9988 output_event = group_leader;
9989 if (flags & PERF_FLAG_FD_NO_GROUP)
9990 group_leader = NULL;
9993 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9994 task = find_lively_task_by_vpid(pid);
9996 err = PTR_ERR(task);
10001 if (task && group_leader &&
10002 group_leader->attr.inherit != attr.inherit) {
10008 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10013 * Reuse ptrace permission checks for now.
10015 * We must hold cred_guard_mutex across this and any potential
10016 * perf_install_in_context() call for this new event to
10017 * serialize against exec() altering our credentials (and the
10018 * perf_event_exit_task() that could imply).
10021 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10025 if (flags & PERF_FLAG_PID_CGROUP)
10028 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10029 NULL, NULL, cgroup_fd);
10030 if (IS_ERR(event)) {
10031 err = PTR_ERR(event);
10035 if (is_sampling_event(event)) {
10036 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10043 * Special case software events and allow them to be part of
10044 * any hardware group.
10048 if (attr.use_clockid) {
10049 err = perf_event_set_clock(event, attr.clockid);
10054 if (pmu->task_ctx_nr == perf_sw_context)
10055 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10057 if (group_leader &&
10058 (is_software_event(event) != is_software_event(group_leader))) {
10059 if (is_software_event(event)) {
10061 * If event and group_leader are not both a software
10062 * event, and event is, then group leader is not.
10064 * Allow the addition of software events to !software
10065 * groups, this is safe because software events never
10066 * fail to schedule.
10068 pmu = group_leader->pmu;
10069 } else if (is_software_event(group_leader) &&
10070 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10072 * In case the group is a pure software group, and we
10073 * try to add a hardware event, move the whole group to
10074 * the hardware context.
10081 * Get the target context (task or percpu):
10083 ctx = find_get_context(pmu, task, event);
10085 err = PTR_ERR(ctx);
10089 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10095 * Look up the group leader (we will attach this event to it):
10097 if (group_leader) {
10101 * Do not allow a recursive hierarchy (this new sibling
10102 * becoming part of another group-sibling):
10104 if (group_leader->group_leader != group_leader)
10107 /* All events in a group should have the same clock */
10108 if (group_leader->clock != event->clock)
10112 * Make sure we're both events for the same CPU;
10113 * grouping events for different CPUs is broken; since
10114 * you can never concurrently schedule them anyhow.
10116 if (group_leader->cpu != event->cpu)
10120 * Make sure we're both on the same task, or both
10123 if (group_leader->ctx->task != ctx->task)
10127 * Do not allow to attach to a group in a different task
10128 * or CPU context. If we're moving SW events, we'll fix
10129 * this up later, so allow that.
10131 if (!move_group && group_leader->ctx != ctx)
10135 * Only a group leader can be exclusive or pinned
10137 if (attr.exclusive || attr.pinned)
10141 if (output_event) {
10142 err = perf_event_set_output(event, output_event);
10147 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10149 if (IS_ERR(event_file)) {
10150 err = PTR_ERR(event_file);
10156 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10158 if (gctx->task == TASK_TOMBSTONE) {
10164 * Check if we raced against another sys_perf_event_open() call
10165 * moving the software group underneath us.
10167 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10169 * If someone moved the group out from under us, check
10170 * if this new event wound up on the same ctx, if so
10171 * its the regular !move_group case, otherwise fail.
10177 perf_event_ctx_unlock(group_leader, gctx);
10182 mutex_lock(&ctx->mutex);
10185 if (ctx->task == TASK_TOMBSTONE) {
10190 if (!perf_event_validate_size(event)) {
10197 * Check if the @cpu we're creating an event for is online.
10199 * We use the perf_cpu_context::ctx::mutex to serialize against
10200 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10202 struct perf_cpu_context *cpuctx =
10203 container_of(ctx, struct perf_cpu_context, ctx);
10205 if (!cpuctx->online) {
10213 * Must be under the same ctx::mutex as perf_install_in_context(),
10214 * because we need to serialize with concurrent event creation.
10216 if (!exclusive_event_installable(event, ctx)) {
10217 /* exclusive and group stuff are assumed mutually exclusive */
10218 WARN_ON_ONCE(move_group);
10224 WARN_ON_ONCE(ctx->parent_ctx);
10227 * This is the point on no return; we cannot fail hereafter. This is
10228 * where we start modifying current state.
10233 * See perf_event_ctx_lock() for comments on the details
10234 * of swizzling perf_event::ctx.
10236 perf_remove_from_context(group_leader, 0);
10239 list_for_each_entry(sibling, &group_leader->sibling_list,
10241 perf_remove_from_context(sibling, 0);
10246 * Wait for everybody to stop referencing the events through
10247 * the old lists, before installing it on new lists.
10252 * Install the group siblings before the group leader.
10254 * Because a group leader will try and install the entire group
10255 * (through the sibling list, which is still in-tact), we can
10256 * end up with siblings installed in the wrong context.
10258 * By installing siblings first we NO-OP because they're not
10259 * reachable through the group lists.
10261 list_for_each_entry(sibling, &group_leader->sibling_list,
10263 perf_event__state_init(sibling);
10264 perf_install_in_context(ctx, sibling, sibling->cpu);
10269 * Removing from the context ends up with disabled
10270 * event. What we want here is event in the initial
10271 * startup state, ready to be add into new context.
10273 perf_event__state_init(group_leader);
10274 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10279 * Precalculate sample_data sizes; do while holding ctx::mutex such
10280 * that we're serialized against further additions and before
10281 * perf_install_in_context() which is the point the event is active and
10282 * can use these values.
10284 perf_event__header_size(event);
10285 perf_event__id_header_size(event);
10287 event->owner = current;
10289 perf_install_in_context(ctx, event, event->cpu);
10290 perf_unpin_context(ctx);
10293 perf_event_ctx_unlock(group_leader, gctx);
10294 mutex_unlock(&ctx->mutex);
10297 mutex_unlock(&task->signal->cred_guard_mutex);
10298 put_task_struct(task);
10301 mutex_lock(¤t->perf_event_mutex);
10302 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10303 mutex_unlock(¤t->perf_event_mutex);
10306 * Drop the reference on the group_event after placing the
10307 * new event on the sibling_list. This ensures destruction
10308 * of the group leader will find the pointer to itself in
10309 * perf_group_detach().
10312 fd_install(event_fd, event_file);
10317 perf_event_ctx_unlock(group_leader, gctx);
10318 mutex_unlock(&ctx->mutex);
10322 perf_unpin_context(ctx);
10326 * If event_file is set, the fput() above will have called ->release()
10327 * and that will take care of freeing the event.
10333 mutex_unlock(&task->signal->cred_guard_mutex);
10336 put_task_struct(task);
10340 put_unused_fd(event_fd);
10345 * perf_event_create_kernel_counter
10347 * @attr: attributes of the counter to create
10348 * @cpu: cpu in which the counter is bound
10349 * @task: task to profile (NULL for percpu)
10351 struct perf_event *
10352 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10353 struct task_struct *task,
10354 perf_overflow_handler_t overflow_handler,
10357 struct perf_event_context *ctx;
10358 struct perf_event *event;
10362 * Get the target context (task or percpu):
10365 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10366 overflow_handler, context, -1);
10367 if (IS_ERR(event)) {
10368 err = PTR_ERR(event);
10372 /* Mark owner so we could distinguish it from user events. */
10373 event->owner = TASK_TOMBSTONE;
10375 ctx = find_get_context(event->pmu, task, event);
10377 err = PTR_ERR(ctx);
10381 WARN_ON_ONCE(ctx->parent_ctx);
10382 mutex_lock(&ctx->mutex);
10383 if (ctx->task == TASK_TOMBSTONE) {
10390 * Check if the @cpu we're creating an event for is online.
10392 * We use the perf_cpu_context::ctx::mutex to serialize against
10393 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10395 struct perf_cpu_context *cpuctx =
10396 container_of(ctx, struct perf_cpu_context, ctx);
10397 if (!cpuctx->online) {
10403 if (!exclusive_event_installable(event, ctx)) {
10408 perf_install_in_context(ctx, event, cpu);
10409 perf_unpin_context(ctx);
10410 mutex_unlock(&ctx->mutex);
10415 mutex_unlock(&ctx->mutex);
10416 perf_unpin_context(ctx);
10421 return ERR_PTR(err);
10423 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10425 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10427 struct perf_event_context *src_ctx;
10428 struct perf_event_context *dst_ctx;
10429 struct perf_event *event, *tmp;
10432 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10433 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10436 * See perf_event_ctx_lock() for comments on the details
10437 * of swizzling perf_event::ctx.
10439 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10440 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10442 perf_remove_from_context(event, 0);
10443 unaccount_event_cpu(event, src_cpu);
10445 list_add(&event->migrate_entry, &events);
10449 * Wait for the events to quiesce before re-instating them.
10454 * Re-instate events in 2 passes.
10456 * Skip over group leaders and only install siblings on this first
10457 * pass, siblings will not get enabled without a leader, however a
10458 * leader will enable its siblings, even if those are still on the old
10461 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10462 if (event->group_leader == event)
10465 list_del(&event->migrate_entry);
10466 if (event->state >= PERF_EVENT_STATE_OFF)
10467 event->state = PERF_EVENT_STATE_INACTIVE;
10468 account_event_cpu(event, dst_cpu);
10469 perf_install_in_context(dst_ctx, event, dst_cpu);
10474 * Once all the siblings are setup properly, install the group leaders
10477 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10478 list_del(&event->migrate_entry);
10479 if (event->state >= PERF_EVENT_STATE_OFF)
10480 event->state = PERF_EVENT_STATE_INACTIVE;
10481 account_event_cpu(event, dst_cpu);
10482 perf_install_in_context(dst_ctx, event, dst_cpu);
10485 mutex_unlock(&dst_ctx->mutex);
10486 mutex_unlock(&src_ctx->mutex);
10488 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10490 static void sync_child_event(struct perf_event *child_event,
10491 struct task_struct *child)
10493 struct perf_event *parent_event = child_event->parent;
10496 if (child_event->attr.inherit_stat)
10497 perf_event_read_event(child_event, child);
10499 child_val = perf_event_count(child_event);
10502 * Add back the child's count to the parent's count:
10504 atomic64_add(child_val, &parent_event->child_count);
10505 atomic64_add(child_event->total_time_enabled,
10506 &parent_event->child_total_time_enabled);
10507 atomic64_add(child_event->total_time_running,
10508 &parent_event->child_total_time_running);
10512 perf_event_exit_event(struct perf_event *child_event,
10513 struct perf_event_context *child_ctx,
10514 struct task_struct *child)
10516 struct perf_event *parent_event = child_event->parent;
10519 * Do not destroy the 'original' grouping; because of the context
10520 * switch optimization the original events could've ended up in a
10521 * random child task.
10523 * If we were to destroy the original group, all group related
10524 * operations would cease to function properly after this random
10527 * Do destroy all inherited groups, we don't care about those
10528 * and being thorough is better.
10530 raw_spin_lock_irq(&child_ctx->lock);
10531 WARN_ON_ONCE(child_ctx->is_active);
10534 perf_group_detach(child_event);
10535 list_del_event(child_event, child_ctx);
10536 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10537 raw_spin_unlock_irq(&child_ctx->lock);
10540 * Parent events are governed by their filedesc, retain them.
10542 if (!parent_event) {
10543 perf_event_wakeup(child_event);
10547 * Child events can be cleaned up.
10550 sync_child_event(child_event, child);
10553 * Remove this event from the parent's list
10555 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10556 mutex_lock(&parent_event->child_mutex);
10557 list_del_init(&child_event->child_list);
10558 mutex_unlock(&parent_event->child_mutex);
10561 * Kick perf_poll() for is_event_hup().
10563 perf_event_wakeup(parent_event);
10564 free_event(child_event);
10565 put_event(parent_event);
10568 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10570 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10571 struct perf_event *child_event, *next;
10573 WARN_ON_ONCE(child != current);
10575 child_ctx = perf_pin_task_context(child, ctxn);
10580 * In order to reduce the amount of tricky in ctx tear-down, we hold
10581 * ctx::mutex over the entire thing. This serializes against almost
10582 * everything that wants to access the ctx.
10584 * The exception is sys_perf_event_open() /
10585 * perf_event_create_kernel_count() which does find_get_context()
10586 * without ctx::mutex (it cannot because of the move_group double mutex
10587 * lock thing). See the comments in perf_install_in_context().
10589 mutex_lock(&child_ctx->mutex);
10592 * In a single ctx::lock section, de-schedule the events and detach the
10593 * context from the task such that we cannot ever get it scheduled back
10596 raw_spin_lock_irq(&child_ctx->lock);
10597 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10600 * Now that the context is inactive, destroy the task <-> ctx relation
10601 * and mark the context dead.
10603 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10604 put_ctx(child_ctx); /* cannot be last */
10605 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10606 put_task_struct(current); /* cannot be last */
10608 clone_ctx = unclone_ctx(child_ctx);
10609 raw_spin_unlock_irq(&child_ctx->lock);
10612 put_ctx(clone_ctx);
10615 * Report the task dead after unscheduling the events so that we
10616 * won't get any samples after PERF_RECORD_EXIT. We can however still
10617 * get a few PERF_RECORD_READ events.
10619 perf_event_task(child, child_ctx, 0);
10621 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10622 perf_event_exit_event(child_event, child_ctx, child);
10624 mutex_unlock(&child_ctx->mutex);
10626 put_ctx(child_ctx);
10630 * When a child task exits, feed back event values to parent events.
10632 * Can be called with cred_guard_mutex held when called from
10633 * install_exec_creds().
10635 void perf_event_exit_task(struct task_struct *child)
10637 struct perf_event *event, *tmp;
10640 mutex_lock(&child->perf_event_mutex);
10641 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10643 list_del_init(&event->owner_entry);
10646 * Ensure the list deletion is visible before we clear
10647 * the owner, closes a race against perf_release() where
10648 * we need to serialize on the owner->perf_event_mutex.
10650 smp_store_release(&event->owner, NULL);
10652 mutex_unlock(&child->perf_event_mutex);
10654 for_each_task_context_nr(ctxn)
10655 perf_event_exit_task_context(child, ctxn);
10658 * The perf_event_exit_task_context calls perf_event_task
10659 * with child's task_ctx, which generates EXIT events for
10660 * child contexts and sets child->perf_event_ctxp[] to NULL.
10661 * At this point we need to send EXIT events to cpu contexts.
10663 perf_event_task(child, NULL, 0);
10666 static void perf_free_event(struct perf_event *event,
10667 struct perf_event_context *ctx)
10669 struct perf_event *parent = event->parent;
10671 if (WARN_ON_ONCE(!parent))
10674 mutex_lock(&parent->child_mutex);
10675 list_del_init(&event->child_list);
10676 mutex_unlock(&parent->child_mutex);
10680 raw_spin_lock_irq(&ctx->lock);
10681 perf_group_detach(event);
10682 list_del_event(event, ctx);
10683 raw_spin_unlock_irq(&ctx->lock);
10688 * Free an unexposed, unused context as created by inheritance by
10689 * perf_event_init_task below, used by fork() in case of fail.
10691 * Not all locks are strictly required, but take them anyway to be nice and
10692 * help out with the lockdep assertions.
10694 void perf_event_free_task(struct task_struct *task)
10696 struct perf_event_context *ctx;
10697 struct perf_event *event, *tmp;
10700 for_each_task_context_nr(ctxn) {
10701 ctx = task->perf_event_ctxp[ctxn];
10705 mutex_lock(&ctx->mutex);
10706 raw_spin_lock_irq(&ctx->lock);
10708 * Destroy the task <-> ctx relation and mark the context dead.
10710 * This is important because even though the task hasn't been
10711 * exposed yet the context has been (through child_list).
10713 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10714 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10715 put_task_struct(task); /* cannot be last */
10716 raw_spin_unlock_irq(&ctx->lock);
10718 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10719 perf_free_event(event, ctx);
10721 mutex_unlock(&ctx->mutex);
10726 void perf_event_delayed_put(struct task_struct *task)
10730 for_each_task_context_nr(ctxn)
10731 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10734 struct file *perf_event_get(unsigned int fd)
10738 file = fget_raw(fd);
10740 return ERR_PTR(-EBADF);
10742 if (file->f_op != &perf_fops) {
10744 return ERR_PTR(-EBADF);
10750 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10753 return ERR_PTR(-EINVAL);
10755 return &event->attr;
10759 * Inherit a event from parent task to child task.
10762 * - valid pointer on success
10763 * - NULL for orphaned events
10764 * - IS_ERR() on error
10766 static struct perf_event *
10767 inherit_event(struct perf_event *parent_event,
10768 struct task_struct *parent,
10769 struct perf_event_context *parent_ctx,
10770 struct task_struct *child,
10771 struct perf_event *group_leader,
10772 struct perf_event_context *child_ctx)
10774 enum perf_event_active_state parent_state = parent_event->state;
10775 struct perf_event *child_event;
10776 unsigned long flags;
10779 * Instead of creating recursive hierarchies of events,
10780 * we link inherited events back to the original parent,
10781 * which has a filp for sure, which we use as the reference
10784 if (parent_event->parent)
10785 parent_event = parent_event->parent;
10787 child_event = perf_event_alloc(&parent_event->attr,
10790 group_leader, parent_event,
10792 if (IS_ERR(child_event))
10793 return child_event;
10796 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10797 * must be under the same lock in order to serialize against
10798 * perf_event_release_kernel(), such that either we must observe
10799 * is_orphaned_event() or they will observe us on the child_list.
10801 mutex_lock(&parent_event->child_mutex);
10802 if (is_orphaned_event(parent_event) ||
10803 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10804 mutex_unlock(&parent_event->child_mutex);
10805 free_event(child_event);
10809 get_ctx(child_ctx);
10812 * Make the child state follow the state of the parent event,
10813 * not its attr.disabled bit. We hold the parent's mutex,
10814 * so we won't race with perf_event_{en, dis}able_family.
10816 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10817 child_event->state = PERF_EVENT_STATE_INACTIVE;
10819 child_event->state = PERF_EVENT_STATE_OFF;
10821 if (parent_event->attr.freq) {
10822 u64 sample_period = parent_event->hw.sample_period;
10823 struct hw_perf_event *hwc = &child_event->hw;
10825 hwc->sample_period = sample_period;
10826 hwc->last_period = sample_period;
10828 local64_set(&hwc->period_left, sample_period);
10831 child_event->ctx = child_ctx;
10832 child_event->overflow_handler = parent_event->overflow_handler;
10833 child_event->overflow_handler_context
10834 = parent_event->overflow_handler_context;
10837 * Precalculate sample_data sizes
10839 perf_event__header_size(child_event);
10840 perf_event__id_header_size(child_event);
10843 * Link it up in the child's context:
10845 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10846 add_event_to_ctx(child_event, child_ctx);
10847 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10850 * Link this into the parent event's child list
10852 list_add_tail(&child_event->child_list, &parent_event->child_list);
10853 mutex_unlock(&parent_event->child_mutex);
10855 return child_event;
10859 * Inherits an event group.
10861 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10862 * This matches with perf_event_release_kernel() removing all child events.
10868 static int inherit_group(struct perf_event *parent_event,
10869 struct task_struct *parent,
10870 struct perf_event_context *parent_ctx,
10871 struct task_struct *child,
10872 struct perf_event_context *child_ctx)
10874 struct perf_event *leader;
10875 struct perf_event *sub;
10876 struct perf_event *child_ctr;
10878 leader = inherit_event(parent_event, parent, parent_ctx,
10879 child, NULL, child_ctx);
10880 if (IS_ERR(leader))
10881 return PTR_ERR(leader);
10883 * @leader can be NULL here because of is_orphaned_event(). In this
10884 * case inherit_event() will create individual events, similar to what
10885 * perf_group_detach() would do anyway.
10887 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10888 child_ctr = inherit_event(sub, parent, parent_ctx,
10889 child, leader, child_ctx);
10890 if (IS_ERR(child_ctr))
10891 return PTR_ERR(child_ctr);
10897 * Creates the child task context and tries to inherit the event-group.
10899 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10900 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10901 * consistent with perf_event_release_kernel() removing all child events.
10908 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10909 struct perf_event_context *parent_ctx,
10910 struct task_struct *child, int ctxn,
10911 int *inherited_all)
10914 struct perf_event_context *child_ctx;
10916 if (!event->attr.inherit) {
10917 *inherited_all = 0;
10921 child_ctx = child->perf_event_ctxp[ctxn];
10924 * This is executed from the parent task context, so
10925 * inherit events that have been marked for cloning.
10926 * First allocate and initialize a context for the
10929 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10933 child->perf_event_ctxp[ctxn] = child_ctx;
10936 ret = inherit_group(event, parent, parent_ctx,
10940 *inherited_all = 0;
10946 * Initialize the perf_event context in task_struct
10948 static int perf_event_init_context(struct task_struct *child, int ctxn)
10950 struct perf_event_context *child_ctx, *parent_ctx;
10951 struct perf_event_context *cloned_ctx;
10952 struct perf_event *event;
10953 struct task_struct *parent = current;
10954 int inherited_all = 1;
10955 unsigned long flags;
10958 if (likely(!parent->perf_event_ctxp[ctxn]))
10962 * If the parent's context is a clone, pin it so it won't get
10963 * swapped under us.
10965 parent_ctx = perf_pin_task_context(parent, ctxn);
10970 * No need to check if parent_ctx != NULL here; since we saw
10971 * it non-NULL earlier, the only reason for it to become NULL
10972 * is if we exit, and since we're currently in the middle of
10973 * a fork we can't be exiting at the same time.
10977 * Lock the parent list. No need to lock the child - not PID
10978 * hashed yet and not running, so nobody can access it.
10980 mutex_lock(&parent_ctx->mutex);
10983 * We dont have to disable NMIs - we are only looking at
10984 * the list, not manipulating it:
10986 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10987 ret = inherit_task_group(event, parent, parent_ctx,
10988 child, ctxn, &inherited_all);
10994 * We can't hold ctx->lock when iterating the ->flexible_group list due
10995 * to allocations, but we need to prevent rotation because
10996 * rotate_ctx() will change the list from interrupt context.
10998 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10999 parent_ctx->rotate_disable = 1;
11000 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11002 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
11003 ret = inherit_task_group(event, parent, parent_ctx,
11004 child, ctxn, &inherited_all);
11009 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11010 parent_ctx->rotate_disable = 0;
11012 child_ctx = child->perf_event_ctxp[ctxn];
11014 if (child_ctx && inherited_all) {
11016 * Mark the child context as a clone of the parent
11017 * context, or of whatever the parent is a clone of.
11019 * Note that if the parent is a clone, the holding of
11020 * parent_ctx->lock avoids it from being uncloned.
11022 cloned_ctx = parent_ctx->parent_ctx;
11024 child_ctx->parent_ctx = cloned_ctx;
11025 child_ctx->parent_gen = parent_ctx->parent_gen;
11027 child_ctx->parent_ctx = parent_ctx;
11028 child_ctx->parent_gen = parent_ctx->generation;
11030 get_ctx(child_ctx->parent_ctx);
11033 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11035 mutex_unlock(&parent_ctx->mutex);
11037 perf_unpin_context(parent_ctx);
11038 put_ctx(parent_ctx);
11044 * Initialize the perf_event context in task_struct
11046 int perf_event_init_task(struct task_struct *child)
11050 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11051 mutex_init(&child->perf_event_mutex);
11052 INIT_LIST_HEAD(&child->perf_event_list);
11054 for_each_task_context_nr(ctxn) {
11055 ret = perf_event_init_context(child, ctxn);
11057 perf_event_free_task(child);
11065 static void __init perf_event_init_all_cpus(void)
11067 struct swevent_htable *swhash;
11070 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11072 for_each_possible_cpu(cpu) {
11073 swhash = &per_cpu(swevent_htable, cpu);
11074 mutex_init(&swhash->hlist_mutex);
11075 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11077 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11078 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11080 #ifdef CONFIG_CGROUP_PERF
11081 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11083 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11087 void perf_swevent_init_cpu(unsigned int cpu)
11089 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11091 mutex_lock(&swhash->hlist_mutex);
11092 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11093 struct swevent_hlist *hlist;
11095 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11097 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11099 mutex_unlock(&swhash->hlist_mutex);
11102 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11103 static void __perf_event_exit_context(void *__info)
11105 struct perf_event_context *ctx = __info;
11106 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11107 struct perf_event *event;
11109 raw_spin_lock(&ctx->lock);
11110 list_for_each_entry(event, &ctx->event_list, event_entry)
11111 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11112 raw_spin_unlock(&ctx->lock);
11115 static void perf_event_exit_cpu_context(int cpu)
11117 struct perf_cpu_context *cpuctx;
11118 struct perf_event_context *ctx;
11121 mutex_lock(&pmus_lock);
11122 list_for_each_entry(pmu, &pmus, entry) {
11123 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11124 ctx = &cpuctx->ctx;
11126 mutex_lock(&ctx->mutex);
11127 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11128 cpuctx->online = 0;
11129 mutex_unlock(&ctx->mutex);
11131 cpumask_clear_cpu(cpu, perf_online_mask);
11132 mutex_unlock(&pmus_lock);
11136 static void perf_event_exit_cpu_context(int cpu) { }
11140 int perf_event_init_cpu(unsigned int cpu)
11142 struct perf_cpu_context *cpuctx;
11143 struct perf_event_context *ctx;
11146 perf_swevent_init_cpu(cpu);
11148 mutex_lock(&pmus_lock);
11149 cpumask_set_cpu(cpu, perf_online_mask);
11150 list_for_each_entry(pmu, &pmus, entry) {
11151 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11152 ctx = &cpuctx->ctx;
11154 mutex_lock(&ctx->mutex);
11155 cpuctx->online = 1;
11156 mutex_unlock(&ctx->mutex);
11158 mutex_unlock(&pmus_lock);
11163 int perf_event_exit_cpu(unsigned int cpu)
11165 perf_event_exit_cpu_context(cpu);
11170 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11174 for_each_online_cpu(cpu)
11175 perf_event_exit_cpu(cpu);
11181 * Run the perf reboot notifier at the very last possible moment so that
11182 * the generic watchdog code runs as long as possible.
11184 static struct notifier_block perf_reboot_notifier = {
11185 .notifier_call = perf_reboot,
11186 .priority = INT_MIN,
11189 void __init perf_event_init(void)
11193 idr_init(&pmu_idr);
11195 perf_event_init_all_cpus();
11196 init_srcu_struct(&pmus_srcu);
11197 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11198 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11199 perf_pmu_register(&perf_task_clock, NULL, -1);
11200 perf_tp_register();
11201 perf_event_init_cpu(smp_processor_id());
11202 register_reboot_notifier(&perf_reboot_notifier);
11204 ret = init_hw_breakpoint();
11205 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11208 * Build time assertion that we keep the data_head at the intended
11209 * location. IOW, validation we got the __reserved[] size right.
11211 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11215 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11218 struct perf_pmu_events_attr *pmu_attr =
11219 container_of(attr, struct perf_pmu_events_attr, attr);
11221 if (pmu_attr->event_str)
11222 return sprintf(page, "%s\n", pmu_attr->event_str);
11226 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11228 static int __init perf_event_sysfs_init(void)
11233 mutex_lock(&pmus_lock);
11235 ret = bus_register(&pmu_bus);
11239 list_for_each_entry(pmu, &pmus, entry) {
11240 if (!pmu->name || pmu->type < 0)
11243 ret = pmu_dev_alloc(pmu);
11244 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11246 pmu_bus_running = 1;
11250 mutex_unlock(&pmus_lock);
11254 device_initcall(perf_event_sysfs_init);
11256 #ifdef CONFIG_CGROUP_PERF
11257 static struct cgroup_subsys_state *
11258 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11260 struct perf_cgroup *jc;
11262 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11264 return ERR_PTR(-ENOMEM);
11266 jc->info = alloc_percpu(struct perf_cgroup_info);
11269 return ERR_PTR(-ENOMEM);
11275 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11277 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11279 free_percpu(jc->info);
11283 static int __perf_cgroup_move(void *info)
11285 struct task_struct *task = info;
11287 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11292 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11294 struct task_struct *task;
11295 struct cgroup_subsys_state *css;
11297 cgroup_taskset_for_each(task, css, tset)
11298 task_function_call(task, __perf_cgroup_move, task);
11301 struct cgroup_subsys perf_event_cgrp_subsys = {
11302 .css_alloc = perf_cgroup_css_alloc,
11303 .css_free = perf_cgroup_css_free,
11304 .attach = perf_cgroup_attach,
11306 * Implicitly enable on dfl hierarchy so that perf events can
11307 * always be filtered by cgroup2 path as long as perf_event
11308 * controller is not mounted on a legacy hierarchy.
11310 .implicit_on_dfl = true,
11313 #endif /* CONFIG_CGROUP_PERF */