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;
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 ctx_event_type = event_type & EVENT_ALL;
2337 perf_pmu_disable(cpuctx->ctx.pmu);
2339 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2342 * Decide which cpu ctx groups to schedule out based on the types
2343 * of events that caused rescheduling:
2344 * - EVENT_CPU: schedule out corresponding groups;
2345 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2346 * - otherwise, do nothing more.
2349 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2350 else if (ctx_event_type & EVENT_PINNED)
2351 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2353 perf_event_sched_in(cpuctx, task_ctx, current);
2354 perf_pmu_enable(cpuctx->ctx.pmu);
2358 * Cross CPU call to install and enable a performance event
2360 * Very similar to remote_function() + event_function() but cannot assume that
2361 * things like ctx->is_active and cpuctx->task_ctx are set.
2363 static int __perf_install_in_context(void *info)
2365 struct perf_event *event = info;
2366 struct perf_event_context *ctx = event->ctx;
2367 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2368 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2369 bool reprogram = true;
2372 raw_spin_lock(&cpuctx->ctx.lock);
2374 raw_spin_lock(&ctx->lock);
2377 reprogram = (ctx->task == current);
2380 * If the task is running, it must be running on this CPU,
2381 * otherwise we cannot reprogram things.
2383 * If its not running, we don't care, ctx->lock will
2384 * serialize against it becoming runnable.
2386 if (task_curr(ctx->task) && !reprogram) {
2391 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2392 } else if (task_ctx) {
2393 raw_spin_lock(&task_ctx->lock);
2397 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2398 add_event_to_ctx(event, ctx);
2399 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2401 add_event_to_ctx(event, ctx);
2405 perf_ctx_unlock(cpuctx, task_ctx);
2411 * Attach a performance event to a context.
2413 * Very similar to event_function_call, see comment there.
2416 perf_install_in_context(struct perf_event_context *ctx,
2417 struct perf_event *event,
2420 struct task_struct *task = READ_ONCE(ctx->task);
2422 lockdep_assert_held(&ctx->mutex);
2424 if (event->cpu != -1)
2428 * Ensures that if we can observe event->ctx, both the event and ctx
2429 * will be 'complete'. See perf_iterate_sb_cpu().
2431 smp_store_release(&event->ctx, ctx);
2434 cpu_function_call(cpu, __perf_install_in_context, event);
2439 * Should not happen, we validate the ctx is still alive before calling.
2441 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2445 * Installing events is tricky because we cannot rely on ctx->is_active
2446 * to be set in case this is the nr_events 0 -> 1 transition.
2448 * Instead we use task_curr(), which tells us if the task is running.
2449 * However, since we use task_curr() outside of rq::lock, we can race
2450 * against the actual state. This means the result can be wrong.
2452 * If we get a false positive, we retry, this is harmless.
2454 * If we get a false negative, things are complicated. If we are after
2455 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2456 * value must be correct. If we're before, it doesn't matter since
2457 * perf_event_context_sched_in() will program the counter.
2459 * However, this hinges on the remote context switch having observed
2460 * our task->perf_event_ctxp[] store, such that it will in fact take
2461 * ctx::lock in perf_event_context_sched_in().
2463 * We do this by task_function_call(), if the IPI fails to hit the task
2464 * we know any future context switch of task must see the
2465 * perf_event_ctpx[] store.
2469 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2470 * task_cpu() load, such that if the IPI then does not find the task
2471 * running, a future context switch of that task must observe the
2476 if (!task_function_call(task, __perf_install_in_context, event))
2479 raw_spin_lock_irq(&ctx->lock);
2481 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2483 * Cannot happen because we already checked above (which also
2484 * cannot happen), and we hold ctx->mutex, which serializes us
2485 * against perf_event_exit_task_context().
2487 raw_spin_unlock_irq(&ctx->lock);
2491 * If the task is not running, ctx->lock will avoid it becoming so,
2492 * thus we can safely install the event.
2494 if (task_curr(task)) {
2495 raw_spin_unlock_irq(&ctx->lock);
2498 add_event_to_ctx(event, ctx);
2499 raw_spin_unlock_irq(&ctx->lock);
2503 * Put a event into inactive state and update time fields.
2504 * Enabling the leader of a group effectively enables all
2505 * the group members that aren't explicitly disabled, so we
2506 * have to update their ->tstamp_enabled also.
2507 * Note: this works for group members as well as group leaders
2508 * since the non-leader members' sibling_lists will be empty.
2510 static void __perf_event_mark_enabled(struct perf_event *event)
2512 struct perf_event *sub;
2513 u64 tstamp = perf_event_time(event);
2515 event->state = PERF_EVENT_STATE_INACTIVE;
2516 __perf_event_enable_time(event, tstamp);
2517 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2518 /* XXX should not be > INACTIVE if event isn't */
2519 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2520 __perf_event_enable_time(sub, tstamp);
2525 * Cross CPU call to enable a performance event
2527 static void __perf_event_enable(struct perf_event *event,
2528 struct perf_cpu_context *cpuctx,
2529 struct perf_event_context *ctx,
2532 struct perf_event *leader = event->group_leader;
2533 struct perf_event_context *task_ctx;
2535 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2536 event->state <= PERF_EVENT_STATE_ERROR)
2540 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2542 __perf_event_mark_enabled(event);
2544 if (!ctx->is_active)
2547 if (!event_filter_match(event)) {
2548 if (is_cgroup_event(event))
2549 perf_cgroup_defer_enabled(event);
2550 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2555 * If the event is in a group and isn't the group leader,
2556 * then don't put it on unless the group is on.
2558 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2559 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2563 task_ctx = cpuctx->task_ctx;
2565 WARN_ON_ONCE(task_ctx != ctx);
2567 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2573 * If event->ctx is a cloned context, callers must make sure that
2574 * every task struct that event->ctx->task could possibly point to
2575 * remains valid. This condition is satisfied when called through
2576 * perf_event_for_each_child or perf_event_for_each as described
2577 * for perf_event_disable.
2579 static void _perf_event_enable(struct perf_event *event)
2581 struct perf_event_context *ctx = event->ctx;
2583 raw_spin_lock_irq(&ctx->lock);
2584 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2585 event->state < PERF_EVENT_STATE_ERROR) {
2586 raw_spin_unlock_irq(&ctx->lock);
2591 * If the event is in error state, clear that first.
2593 * That way, if we see the event in error state below, we know that it
2594 * has gone back into error state, as distinct from the task having
2595 * been scheduled away before the cross-call arrived.
2597 if (event->state == PERF_EVENT_STATE_ERROR)
2598 event->state = PERF_EVENT_STATE_OFF;
2599 raw_spin_unlock_irq(&ctx->lock);
2601 event_function_call(event, __perf_event_enable, NULL);
2605 * See perf_event_disable();
2607 void perf_event_enable(struct perf_event *event)
2609 struct perf_event_context *ctx;
2611 ctx = perf_event_ctx_lock(event);
2612 _perf_event_enable(event);
2613 perf_event_ctx_unlock(event, ctx);
2615 EXPORT_SYMBOL_GPL(perf_event_enable);
2617 struct stop_event_data {
2618 struct perf_event *event;
2619 unsigned int restart;
2622 static int __perf_event_stop(void *info)
2624 struct stop_event_data *sd = info;
2625 struct perf_event *event = sd->event;
2627 /* if it's already INACTIVE, do nothing */
2628 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2631 /* matches smp_wmb() in event_sched_in() */
2635 * There is a window with interrupts enabled before we get here,
2636 * so we need to check again lest we try to stop another CPU's event.
2638 if (READ_ONCE(event->oncpu) != smp_processor_id())
2641 event->pmu->stop(event, PERF_EF_UPDATE);
2644 * May race with the actual stop (through perf_pmu_output_stop()),
2645 * but it is only used for events with AUX ring buffer, and such
2646 * events will refuse to restart because of rb::aux_mmap_count==0,
2647 * see comments in perf_aux_output_begin().
2649 * Since this is happening on a event-local CPU, no trace is lost
2653 event->pmu->start(event, 0);
2658 static int perf_event_stop(struct perf_event *event, int restart)
2660 struct stop_event_data sd = {
2667 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2670 /* matches smp_wmb() in event_sched_in() */
2674 * We only want to restart ACTIVE events, so if the event goes
2675 * inactive here (event->oncpu==-1), there's nothing more to do;
2676 * fall through with ret==-ENXIO.
2678 ret = cpu_function_call(READ_ONCE(event->oncpu),
2679 __perf_event_stop, &sd);
2680 } while (ret == -EAGAIN);
2686 * In order to contain the amount of racy and tricky in the address filter
2687 * configuration management, it is a two part process:
2689 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2690 * we update the addresses of corresponding vmas in
2691 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2692 * (p2) when an event is scheduled in (pmu::add), it calls
2693 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2694 * if the generation has changed since the previous call.
2696 * If (p1) happens while the event is active, we restart it to force (p2).
2698 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2699 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2701 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2702 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2704 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2707 void perf_event_addr_filters_sync(struct perf_event *event)
2709 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2711 if (!has_addr_filter(event))
2714 raw_spin_lock(&ifh->lock);
2715 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2716 event->pmu->addr_filters_sync(event);
2717 event->hw.addr_filters_gen = event->addr_filters_gen;
2719 raw_spin_unlock(&ifh->lock);
2721 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2723 static int _perf_event_refresh(struct perf_event *event, int refresh)
2726 * not supported on inherited events
2728 if (event->attr.inherit || !is_sampling_event(event))
2731 atomic_add(refresh, &event->event_limit);
2732 _perf_event_enable(event);
2738 * See perf_event_disable()
2740 int perf_event_refresh(struct perf_event *event, int refresh)
2742 struct perf_event_context *ctx;
2745 ctx = perf_event_ctx_lock(event);
2746 ret = _perf_event_refresh(event, refresh);
2747 perf_event_ctx_unlock(event, ctx);
2751 EXPORT_SYMBOL_GPL(perf_event_refresh);
2753 static void ctx_sched_out(struct perf_event_context *ctx,
2754 struct perf_cpu_context *cpuctx,
2755 enum event_type_t event_type)
2757 int is_active = ctx->is_active;
2758 struct perf_event *event;
2760 lockdep_assert_held(&ctx->lock);
2762 if (likely(!ctx->nr_events)) {
2764 * See __perf_remove_from_context().
2766 WARN_ON_ONCE(ctx->is_active);
2768 WARN_ON_ONCE(cpuctx->task_ctx);
2772 ctx->is_active &= ~event_type;
2773 if (!(ctx->is_active & EVENT_ALL))
2777 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2778 if (!ctx->is_active)
2779 cpuctx->task_ctx = NULL;
2783 * Always update time if it was set; not only when it changes.
2784 * Otherwise we can 'forget' to update time for any but the last
2785 * context we sched out. For example:
2787 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2788 * ctx_sched_out(.event_type = EVENT_PINNED)
2790 * would only update time for the pinned events.
2792 if (is_active & EVENT_TIME) {
2793 /* update (and stop) ctx time */
2794 update_context_time(ctx);
2795 update_cgrp_time_from_cpuctx(cpuctx);
2798 is_active ^= ctx->is_active; /* changed bits */
2800 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2803 perf_pmu_disable(ctx->pmu);
2804 if (is_active & EVENT_PINNED) {
2805 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2806 group_sched_out(event, cpuctx, ctx);
2809 if (is_active & EVENT_FLEXIBLE) {
2810 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2811 group_sched_out(event, cpuctx, ctx);
2813 perf_pmu_enable(ctx->pmu);
2817 * Test whether two contexts are equivalent, i.e. whether they have both been
2818 * cloned from the same version of the same context.
2820 * Equivalence is measured using a generation number in the context that is
2821 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2822 * and list_del_event().
2824 static int context_equiv(struct perf_event_context *ctx1,
2825 struct perf_event_context *ctx2)
2827 lockdep_assert_held(&ctx1->lock);
2828 lockdep_assert_held(&ctx2->lock);
2830 /* Pinning disables the swap optimization */
2831 if (ctx1->pin_count || ctx2->pin_count)
2834 /* If ctx1 is the parent of ctx2 */
2835 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2838 /* If ctx2 is the parent of ctx1 */
2839 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2843 * If ctx1 and ctx2 have the same parent; we flatten the parent
2844 * hierarchy, see perf_event_init_context().
2846 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2847 ctx1->parent_gen == ctx2->parent_gen)
2854 static void __perf_event_sync_stat(struct perf_event *event,
2855 struct perf_event *next_event)
2859 if (!event->attr.inherit_stat)
2863 * Update the event value, we cannot use perf_event_read()
2864 * because we're in the middle of a context switch and have IRQs
2865 * disabled, which upsets smp_call_function_single(), however
2866 * we know the event must be on the current CPU, therefore we
2867 * don't need to use it.
2869 switch (event->state) {
2870 case PERF_EVENT_STATE_ACTIVE:
2871 event->pmu->read(event);
2874 case PERF_EVENT_STATE_INACTIVE:
2875 update_event_times(event);
2883 * In order to keep per-task stats reliable we need to flip the event
2884 * values when we flip the contexts.
2886 value = local64_read(&next_event->count);
2887 value = local64_xchg(&event->count, value);
2888 local64_set(&next_event->count, value);
2890 swap(event->total_time_enabled, next_event->total_time_enabled);
2891 swap(event->total_time_running, next_event->total_time_running);
2894 * Since we swizzled the values, update the user visible data too.
2896 perf_event_update_userpage(event);
2897 perf_event_update_userpage(next_event);
2900 static void perf_event_sync_stat(struct perf_event_context *ctx,
2901 struct perf_event_context *next_ctx)
2903 struct perf_event *event, *next_event;
2908 update_context_time(ctx);
2910 event = list_first_entry(&ctx->event_list,
2911 struct perf_event, event_entry);
2913 next_event = list_first_entry(&next_ctx->event_list,
2914 struct perf_event, event_entry);
2916 while (&event->event_entry != &ctx->event_list &&
2917 &next_event->event_entry != &next_ctx->event_list) {
2919 __perf_event_sync_stat(event, next_event);
2921 event = list_next_entry(event, event_entry);
2922 next_event = list_next_entry(next_event, event_entry);
2926 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2927 struct task_struct *next)
2929 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2930 struct perf_event_context *next_ctx;
2931 struct perf_event_context *parent, *next_parent;
2932 struct perf_cpu_context *cpuctx;
2938 cpuctx = __get_cpu_context(ctx);
2939 if (!cpuctx->task_ctx)
2943 next_ctx = next->perf_event_ctxp[ctxn];
2947 parent = rcu_dereference(ctx->parent_ctx);
2948 next_parent = rcu_dereference(next_ctx->parent_ctx);
2950 /* If neither context have a parent context; they cannot be clones. */
2951 if (!parent && !next_parent)
2954 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2956 * Looks like the two contexts are clones, so we might be
2957 * able to optimize the context switch. We lock both
2958 * contexts and check that they are clones under the
2959 * lock (including re-checking that neither has been
2960 * uncloned in the meantime). It doesn't matter which
2961 * order we take the locks because no other cpu could
2962 * be trying to lock both of these tasks.
2964 raw_spin_lock(&ctx->lock);
2965 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2966 if (context_equiv(ctx, next_ctx)) {
2967 WRITE_ONCE(ctx->task, next);
2968 WRITE_ONCE(next_ctx->task, task);
2970 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2973 * RCU_INIT_POINTER here is safe because we've not
2974 * modified the ctx and the above modification of
2975 * ctx->task and ctx->task_ctx_data are immaterial
2976 * since those values are always verified under
2977 * ctx->lock which we're now holding.
2979 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2980 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2984 perf_event_sync_stat(ctx, next_ctx);
2986 raw_spin_unlock(&next_ctx->lock);
2987 raw_spin_unlock(&ctx->lock);
2993 raw_spin_lock(&ctx->lock);
2994 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2995 raw_spin_unlock(&ctx->lock);
2999 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3001 void perf_sched_cb_dec(struct pmu *pmu)
3003 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3005 this_cpu_dec(perf_sched_cb_usages);
3007 if (!--cpuctx->sched_cb_usage)
3008 list_del(&cpuctx->sched_cb_entry);
3012 void perf_sched_cb_inc(struct pmu *pmu)
3014 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3016 if (!cpuctx->sched_cb_usage++)
3017 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3019 this_cpu_inc(perf_sched_cb_usages);
3023 * This function provides the context switch callback to the lower code
3024 * layer. It is invoked ONLY when the context switch callback is enabled.
3026 * This callback is relevant even to per-cpu events; for example multi event
3027 * PEBS requires this to provide PID/TID information. This requires we flush
3028 * all queued PEBS records before we context switch to a new task.
3030 static void perf_pmu_sched_task(struct task_struct *prev,
3031 struct task_struct *next,
3034 struct perf_cpu_context *cpuctx;
3040 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3041 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3043 if (WARN_ON_ONCE(!pmu->sched_task))
3046 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3047 perf_pmu_disable(pmu);
3049 pmu->sched_task(cpuctx->task_ctx, sched_in);
3051 perf_pmu_enable(pmu);
3052 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3056 static void perf_event_switch(struct task_struct *task,
3057 struct task_struct *next_prev, bool sched_in);
3059 #define for_each_task_context_nr(ctxn) \
3060 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3063 * Called from scheduler to remove the events of the current task,
3064 * with interrupts disabled.
3066 * We stop each event and update the event value in event->count.
3068 * This does not protect us against NMI, but disable()
3069 * sets the disabled bit in the control field of event _before_
3070 * accessing the event control register. If a NMI hits, then it will
3071 * not restart the event.
3073 void __perf_event_task_sched_out(struct task_struct *task,
3074 struct task_struct *next)
3078 if (__this_cpu_read(perf_sched_cb_usages))
3079 perf_pmu_sched_task(task, next, false);
3081 if (atomic_read(&nr_switch_events))
3082 perf_event_switch(task, next, false);
3084 for_each_task_context_nr(ctxn)
3085 perf_event_context_sched_out(task, ctxn, next);
3088 * if cgroup events exist on this CPU, then we need
3089 * to check if we have to switch out PMU state.
3090 * cgroup event are system-wide mode only
3092 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3093 perf_cgroup_sched_out(task, next);
3097 * Called with IRQs disabled
3099 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3100 enum event_type_t event_type)
3102 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3106 ctx_pinned_sched_in(struct perf_event_context *ctx,
3107 struct perf_cpu_context *cpuctx)
3109 struct perf_event *event;
3111 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3112 if (event->state <= PERF_EVENT_STATE_OFF)
3114 if (!event_filter_match(event))
3117 /* may need to reset tstamp_enabled */
3118 if (is_cgroup_event(event))
3119 perf_cgroup_mark_enabled(event, ctx);
3121 if (group_can_go_on(event, cpuctx, 1))
3122 group_sched_in(event, cpuctx, ctx);
3125 * If this pinned group hasn't been scheduled,
3126 * put it in error state.
3128 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3129 update_group_times(event);
3130 event->state = PERF_EVENT_STATE_ERROR;
3136 ctx_flexible_sched_in(struct perf_event_context *ctx,
3137 struct perf_cpu_context *cpuctx)
3139 struct perf_event *event;
3142 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3143 /* Ignore events in OFF or ERROR state */
3144 if (event->state <= PERF_EVENT_STATE_OFF)
3147 * Listen to the 'cpu' scheduling filter constraint
3150 if (!event_filter_match(event))
3153 /* may need to reset tstamp_enabled */
3154 if (is_cgroup_event(event))
3155 perf_cgroup_mark_enabled(event, ctx);
3157 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3158 if (group_sched_in(event, cpuctx, ctx))
3165 ctx_sched_in(struct perf_event_context *ctx,
3166 struct perf_cpu_context *cpuctx,
3167 enum event_type_t event_type,
3168 struct task_struct *task)
3170 int is_active = ctx->is_active;
3173 lockdep_assert_held(&ctx->lock);
3175 if (likely(!ctx->nr_events))
3178 ctx->is_active |= (event_type | EVENT_TIME);
3181 cpuctx->task_ctx = ctx;
3183 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3186 is_active ^= ctx->is_active; /* changed bits */
3188 if (is_active & EVENT_TIME) {
3189 /* start ctx time */
3191 ctx->timestamp = now;
3192 perf_cgroup_set_timestamp(task, ctx);
3196 * First go through the list and put on any pinned groups
3197 * in order to give them the best chance of going on.
3199 if (is_active & EVENT_PINNED)
3200 ctx_pinned_sched_in(ctx, cpuctx);
3202 /* Then walk through the lower prio flexible groups */
3203 if (is_active & EVENT_FLEXIBLE)
3204 ctx_flexible_sched_in(ctx, cpuctx);
3207 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3208 enum event_type_t event_type,
3209 struct task_struct *task)
3211 struct perf_event_context *ctx = &cpuctx->ctx;
3213 ctx_sched_in(ctx, cpuctx, event_type, task);
3216 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3217 struct task_struct *task)
3219 struct perf_cpu_context *cpuctx;
3221 cpuctx = __get_cpu_context(ctx);
3222 if (cpuctx->task_ctx == ctx)
3225 perf_ctx_lock(cpuctx, ctx);
3227 * We must check ctx->nr_events while holding ctx->lock, such
3228 * that we serialize against perf_install_in_context().
3230 if (!ctx->nr_events)
3233 perf_pmu_disable(ctx->pmu);
3235 * We want to keep the following priority order:
3236 * cpu pinned (that don't need to move), task pinned,
3237 * cpu flexible, task flexible.
3239 * However, if task's ctx is not carrying any pinned
3240 * events, no need to flip the cpuctx's events around.
3242 if (!list_empty(&ctx->pinned_groups))
3243 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3244 perf_event_sched_in(cpuctx, ctx, task);
3245 perf_pmu_enable(ctx->pmu);
3248 perf_ctx_unlock(cpuctx, ctx);
3252 * Called from scheduler to add the events of the current task
3253 * with interrupts disabled.
3255 * We restore the event value and then enable it.
3257 * This does not protect us against NMI, but enable()
3258 * sets the enabled bit in the control field of event _before_
3259 * accessing the event control register. If a NMI hits, then it will
3260 * keep the event running.
3262 void __perf_event_task_sched_in(struct task_struct *prev,
3263 struct task_struct *task)
3265 struct perf_event_context *ctx;
3269 * If cgroup events exist on this CPU, then we need to check if we have
3270 * to switch in PMU state; cgroup event are system-wide mode only.
3272 * Since cgroup events are CPU events, we must schedule these in before
3273 * we schedule in the task events.
3275 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3276 perf_cgroup_sched_in(prev, task);
3278 for_each_task_context_nr(ctxn) {
3279 ctx = task->perf_event_ctxp[ctxn];
3283 perf_event_context_sched_in(ctx, task);
3286 if (atomic_read(&nr_switch_events))
3287 perf_event_switch(task, prev, true);
3289 if (__this_cpu_read(perf_sched_cb_usages))
3290 perf_pmu_sched_task(prev, task, true);
3293 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3295 u64 frequency = event->attr.sample_freq;
3296 u64 sec = NSEC_PER_SEC;
3297 u64 divisor, dividend;
3299 int count_fls, nsec_fls, frequency_fls, sec_fls;
3301 count_fls = fls64(count);
3302 nsec_fls = fls64(nsec);
3303 frequency_fls = fls64(frequency);
3307 * We got @count in @nsec, with a target of sample_freq HZ
3308 * the target period becomes:
3311 * period = -------------------
3312 * @nsec * sample_freq
3317 * Reduce accuracy by one bit such that @a and @b converge
3318 * to a similar magnitude.
3320 #define REDUCE_FLS(a, b) \
3322 if (a##_fls > b##_fls) { \
3332 * Reduce accuracy until either term fits in a u64, then proceed with
3333 * the other, so that finally we can do a u64/u64 division.
3335 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3336 REDUCE_FLS(nsec, frequency);
3337 REDUCE_FLS(sec, count);
3340 if (count_fls + sec_fls > 64) {
3341 divisor = nsec * frequency;
3343 while (count_fls + sec_fls > 64) {
3344 REDUCE_FLS(count, sec);
3348 dividend = count * sec;
3350 dividend = count * sec;
3352 while (nsec_fls + frequency_fls > 64) {
3353 REDUCE_FLS(nsec, frequency);
3357 divisor = nsec * frequency;
3363 return div64_u64(dividend, divisor);
3366 static DEFINE_PER_CPU(int, perf_throttled_count);
3367 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3369 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3371 struct hw_perf_event *hwc = &event->hw;
3372 s64 period, sample_period;
3375 period = perf_calculate_period(event, nsec, count);
3377 delta = (s64)(period - hwc->sample_period);
3378 delta = (delta + 7) / 8; /* low pass filter */
3380 sample_period = hwc->sample_period + delta;
3385 hwc->sample_period = sample_period;
3387 if (local64_read(&hwc->period_left) > 8*sample_period) {
3389 event->pmu->stop(event, PERF_EF_UPDATE);
3391 local64_set(&hwc->period_left, 0);
3394 event->pmu->start(event, PERF_EF_RELOAD);
3399 * combine freq adjustment with unthrottling to avoid two passes over the
3400 * events. At the same time, make sure, having freq events does not change
3401 * the rate of unthrottling as that would introduce bias.
3403 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3406 struct perf_event *event;
3407 struct hw_perf_event *hwc;
3408 u64 now, period = TICK_NSEC;
3412 * only need to iterate over all events iff:
3413 * - context have events in frequency mode (needs freq adjust)
3414 * - there are events to unthrottle on this cpu
3416 if (!(ctx->nr_freq || needs_unthr))
3419 raw_spin_lock(&ctx->lock);
3420 perf_pmu_disable(ctx->pmu);
3422 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3423 if (event->state != PERF_EVENT_STATE_ACTIVE)
3426 if (!event_filter_match(event))
3429 perf_pmu_disable(event->pmu);
3433 if (hwc->interrupts == MAX_INTERRUPTS) {
3434 hwc->interrupts = 0;
3435 perf_log_throttle(event, 1);
3436 event->pmu->start(event, 0);
3439 if (!event->attr.freq || !event->attr.sample_freq)
3443 * stop the event and update event->count
3445 event->pmu->stop(event, PERF_EF_UPDATE);
3447 now = local64_read(&event->count);
3448 delta = now - hwc->freq_count_stamp;
3449 hwc->freq_count_stamp = now;
3453 * reload only if value has changed
3454 * we have stopped the event so tell that
3455 * to perf_adjust_period() to avoid stopping it
3459 perf_adjust_period(event, period, delta, false);
3461 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3463 perf_pmu_enable(event->pmu);
3466 perf_pmu_enable(ctx->pmu);
3467 raw_spin_unlock(&ctx->lock);
3471 * Round-robin a context's events:
3473 static void rotate_ctx(struct perf_event_context *ctx)
3476 * Rotate the first entry last of non-pinned groups. Rotation might be
3477 * disabled by the inheritance code.
3479 if (!ctx->rotate_disable)
3480 list_rotate_left(&ctx->flexible_groups);
3483 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3485 struct perf_event_context *ctx = NULL;
3488 if (cpuctx->ctx.nr_events) {
3489 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3493 ctx = cpuctx->task_ctx;
3494 if (ctx && ctx->nr_events) {
3495 if (ctx->nr_events != ctx->nr_active)
3502 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3503 perf_pmu_disable(cpuctx->ctx.pmu);
3505 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3507 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3509 rotate_ctx(&cpuctx->ctx);
3513 perf_event_sched_in(cpuctx, ctx, current);
3515 perf_pmu_enable(cpuctx->ctx.pmu);
3516 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3522 void perf_event_task_tick(void)
3524 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3525 struct perf_event_context *ctx, *tmp;
3528 WARN_ON(!irqs_disabled());
3530 __this_cpu_inc(perf_throttled_seq);
3531 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3532 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3534 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3535 perf_adjust_freq_unthr_context(ctx, throttled);
3538 static int event_enable_on_exec(struct perf_event *event,
3539 struct perf_event_context *ctx)
3541 if (!event->attr.enable_on_exec)
3544 event->attr.enable_on_exec = 0;
3545 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3548 __perf_event_mark_enabled(event);
3554 * Enable all of a task's events that have been marked enable-on-exec.
3555 * This expects task == current.
3557 static void perf_event_enable_on_exec(int ctxn)
3559 struct perf_event_context *ctx, *clone_ctx = NULL;
3560 enum event_type_t event_type = 0;
3561 struct perf_cpu_context *cpuctx;
3562 struct perf_event *event;
3563 unsigned long flags;
3566 local_irq_save(flags);
3567 ctx = current->perf_event_ctxp[ctxn];
3568 if (!ctx || !ctx->nr_events)
3571 cpuctx = __get_cpu_context(ctx);
3572 perf_ctx_lock(cpuctx, ctx);
3573 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3574 list_for_each_entry(event, &ctx->event_list, event_entry) {
3575 enabled |= event_enable_on_exec(event, ctx);
3576 event_type |= get_event_type(event);
3580 * Unclone and reschedule this context if we enabled any event.
3583 clone_ctx = unclone_ctx(ctx);
3584 ctx_resched(cpuctx, ctx, event_type);
3586 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3588 perf_ctx_unlock(cpuctx, ctx);
3591 local_irq_restore(flags);
3597 struct perf_read_data {
3598 struct perf_event *event;
3603 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3605 u16 local_pkg, event_pkg;
3607 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3608 int local_cpu = smp_processor_id();
3610 event_pkg = topology_physical_package_id(event_cpu);
3611 local_pkg = topology_physical_package_id(local_cpu);
3613 if (event_pkg == local_pkg)
3621 * Cross CPU call to read the hardware event
3623 static void __perf_event_read(void *info)
3625 struct perf_read_data *data = info;
3626 struct perf_event *sub, *event = data->event;
3627 struct perf_event_context *ctx = event->ctx;
3628 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3629 struct pmu *pmu = event->pmu;
3632 * If this is a task context, we need to check whether it is
3633 * the current task context of this cpu. If not it has been
3634 * scheduled out before the smp call arrived. In that case
3635 * event->count would have been updated to a recent sample
3636 * when the event was scheduled out.
3638 if (ctx->task && cpuctx->task_ctx != ctx)
3641 raw_spin_lock(&ctx->lock);
3642 if (ctx->is_active) {
3643 update_context_time(ctx);
3644 update_cgrp_time_from_event(event);
3647 update_event_times(event);
3648 if (event->state != PERF_EVENT_STATE_ACTIVE)
3657 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3661 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3662 update_event_times(sub);
3663 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3665 * Use sibling's PMU rather than @event's since
3666 * sibling could be on different (eg: software) PMU.
3668 sub->pmu->read(sub);
3672 data->ret = pmu->commit_txn(pmu);
3675 raw_spin_unlock(&ctx->lock);
3678 static inline u64 perf_event_count(struct perf_event *event)
3680 return local64_read(&event->count) + atomic64_read(&event->child_count);
3684 * NMI-safe method to read a local event, that is an event that
3686 * - either for the current task, or for this CPU
3687 * - does not have inherit set, for inherited task events
3688 * will not be local and we cannot read them atomically
3689 * - must not have a pmu::count method
3691 int perf_event_read_local(struct perf_event *event, u64 *value)
3693 unsigned long flags;
3697 * Disabling interrupts avoids all counter scheduling (context
3698 * switches, timer based rotation and IPIs).
3700 local_irq_save(flags);
3703 * It must not be an event with inherit set, we cannot read
3704 * all child counters from atomic context.
3706 if (event->attr.inherit) {
3711 /* If this is a per-task event, it must be for current */
3712 if ((event->attach_state & PERF_ATTACH_TASK) &&
3713 event->hw.target != current) {
3718 /* If this is a per-CPU event, it must be for this CPU */
3719 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3720 event->cpu != smp_processor_id()) {
3726 * If the event is currently on this CPU, its either a per-task event,
3727 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3730 if (event->oncpu == smp_processor_id())
3731 event->pmu->read(event);
3733 *value = local64_read(&event->count);
3735 local_irq_restore(flags);
3740 static int perf_event_read(struct perf_event *event, bool group)
3742 int event_cpu, ret = 0;
3745 * If event is enabled and currently active on a CPU, update the
3746 * value in the event structure:
3748 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3749 struct perf_read_data data = {
3755 event_cpu = READ_ONCE(event->oncpu);
3756 if ((unsigned)event_cpu >= nr_cpu_ids)
3760 event_cpu = __perf_event_read_cpu(event, event_cpu);
3763 * Purposely ignore the smp_call_function_single() return
3766 * If event_cpu isn't a valid CPU it means the event got
3767 * scheduled out and that will have updated the event count.
3769 * Therefore, either way, we'll have an up-to-date event count
3772 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3775 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3776 struct perf_event_context *ctx = event->ctx;
3777 unsigned long flags;
3779 raw_spin_lock_irqsave(&ctx->lock, flags);
3781 * may read while context is not active
3782 * (e.g., thread is blocked), in that case
3783 * we cannot update context time
3785 if (ctx->is_active) {
3786 update_context_time(ctx);
3787 update_cgrp_time_from_event(event);
3790 update_group_times(event);
3792 update_event_times(event);
3793 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3800 * Initialize the perf_event context in a task_struct:
3802 static void __perf_event_init_context(struct perf_event_context *ctx)
3804 raw_spin_lock_init(&ctx->lock);
3805 mutex_init(&ctx->mutex);
3806 INIT_LIST_HEAD(&ctx->active_ctx_list);
3807 INIT_LIST_HEAD(&ctx->pinned_groups);
3808 INIT_LIST_HEAD(&ctx->flexible_groups);
3809 INIT_LIST_HEAD(&ctx->event_list);
3810 atomic_set(&ctx->refcount, 1);
3813 static struct perf_event_context *
3814 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3816 struct perf_event_context *ctx;
3818 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3822 __perf_event_init_context(ctx);
3825 get_task_struct(task);
3832 static struct task_struct *
3833 find_lively_task_by_vpid(pid_t vpid)
3835 struct task_struct *task;
3841 task = find_task_by_vpid(vpid);
3843 get_task_struct(task);
3847 return ERR_PTR(-ESRCH);
3853 * Returns a matching context with refcount and pincount.
3855 static struct perf_event_context *
3856 find_get_context(struct pmu *pmu, struct task_struct *task,
3857 struct perf_event *event)
3859 struct perf_event_context *ctx, *clone_ctx = NULL;
3860 struct perf_cpu_context *cpuctx;
3861 void *task_ctx_data = NULL;
3862 unsigned long flags;
3864 int cpu = event->cpu;
3867 /* Must be root to operate on a CPU event: */
3868 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3869 return ERR_PTR(-EACCES);
3871 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3880 ctxn = pmu->task_ctx_nr;
3884 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3885 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3886 if (!task_ctx_data) {
3893 ctx = perf_lock_task_context(task, ctxn, &flags);
3895 clone_ctx = unclone_ctx(ctx);
3898 if (task_ctx_data && !ctx->task_ctx_data) {
3899 ctx->task_ctx_data = task_ctx_data;
3900 task_ctx_data = NULL;
3902 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3907 ctx = alloc_perf_context(pmu, task);
3912 if (task_ctx_data) {
3913 ctx->task_ctx_data = task_ctx_data;
3914 task_ctx_data = NULL;
3918 mutex_lock(&task->perf_event_mutex);
3920 * If it has already passed perf_event_exit_task().
3921 * we must see PF_EXITING, it takes this mutex too.
3923 if (task->flags & PF_EXITING)
3925 else if (task->perf_event_ctxp[ctxn])
3930 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3932 mutex_unlock(&task->perf_event_mutex);
3934 if (unlikely(err)) {
3943 kfree(task_ctx_data);
3947 kfree(task_ctx_data);
3948 return ERR_PTR(err);
3951 static void perf_event_free_filter(struct perf_event *event);
3952 static void perf_event_free_bpf_prog(struct perf_event *event);
3954 static void free_event_rcu(struct rcu_head *head)
3956 struct perf_event *event;
3958 event = container_of(head, struct perf_event, rcu_head);
3960 put_pid_ns(event->ns);
3961 perf_event_free_filter(event);
3965 static void ring_buffer_attach(struct perf_event *event,
3966 struct ring_buffer *rb);
3968 static void detach_sb_event(struct perf_event *event)
3970 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3972 raw_spin_lock(&pel->lock);
3973 list_del_rcu(&event->sb_list);
3974 raw_spin_unlock(&pel->lock);
3977 static bool is_sb_event(struct perf_event *event)
3979 struct perf_event_attr *attr = &event->attr;
3984 if (event->attach_state & PERF_ATTACH_TASK)
3987 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3988 attr->comm || attr->comm_exec ||
3990 attr->context_switch)
3995 static void unaccount_pmu_sb_event(struct perf_event *event)
3997 if (is_sb_event(event))
3998 detach_sb_event(event);
4001 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4006 if (is_cgroup_event(event))
4007 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4010 #ifdef CONFIG_NO_HZ_FULL
4011 static DEFINE_SPINLOCK(nr_freq_lock);
4014 static void unaccount_freq_event_nohz(void)
4016 #ifdef CONFIG_NO_HZ_FULL
4017 spin_lock(&nr_freq_lock);
4018 if (atomic_dec_and_test(&nr_freq_events))
4019 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4020 spin_unlock(&nr_freq_lock);
4024 static void unaccount_freq_event(void)
4026 if (tick_nohz_full_enabled())
4027 unaccount_freq_event_nohz();
4029 atomic_dec(&nr_freq_events);
4032 static void unaccount_event(struct perf_event *event)
4039 if (event->attach_state & PERF_ATTACH_TASK)
4041 if (event->attr.mmap || event->attr.mmap_data)
4042 atomic_dec(&nr_mmap_events);
4043 if (event->attr.comm)
4044 atomic_dec(&nr_comm_events);
4045 if (event->attr.namespaces)
4046 atomic_dec(&nr_namespaces_events);
4047 if (event->attr.task)
4048 atomic_dec(&nr_task_events);
4049 if (event->attr.freq)
4050 unaccount_freq_event();
4051 if (event->attr.context_switch) {
4053 atomic_dec(&nr_switch_events);
4055 if (is_cgroup_event(event))
4057 if (has_branch_stack(event))
4061 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4062 schedule_delayed_work(&perf_sched_work, HZ);
4065 unaccount_event_cpu(event, event->cpu);
4067 unaccount_pmu_sb_event(event);
4070 static void perf_sched_delayed(struct work_struct *work)
4072 mutex_lock(&perf_sched_mutex);
4073 if (atomic_dec_and_test(&perf_sched_count))
4074 static_branch_disable(&perf_sched_events);
4075 mutex_unlock(&perf_sched_mutex);
4079 * The following implement mutual exclusion of events on "exclusive" pmus
4080 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4081 * at a time, so we disallow creating events that might conflict, namely:
4083 * 1) cpu-wide events in the presence of per-task events,
4084 * 2) per-task events in the presence of cpu-wide events,
4085 * 3) two matching events on the same context.
4087 * The former two cases are handled in the allocation path (perf_event_alloc(),
4088 * _free_event()), the latter -- before the first perf_install_in_context().
4090 static int exclusive_event_init(struct perf_event *event)
4092 struct pmu *pmu = event->pmu;
4094 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4098 * Prevent co-existence of per-task and cpu-wide events on the
4099 * same exclusive pmu.
4101 * Negative pmu::exclusive_cnt means there are cpu-wide
4102 * events on this "exclusive" pmu, positive means there are
4105 * Since this is called in perf_event_alloc() path, event::ctx
4106 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4107 * to mean "per-task event", because unlike other attach states it
4108 * never gets cleared.
4110 if (event->attach_state & PERF_ATTACH_TASK) {
4111 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4114 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4121 static void exclusive_event_destroy(struct perf_event *event)
4123 struct pmu *pmu = event->pmu;
4125 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4128 /* see comment in exclusive_event_init() */
4129 if (event->attach_state & PERF_ATTACH_TASK)
4130 atomic_dec(&pmu->exclusive_cnt);
4132 atomic_inc(&pmu->exclusive_cnt);
4135 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4137 if ((e1->pmu == e2->pmu) &&
4138 (e1->cpu == e2->cpu ||
4145 /* Called under the same ctx::mutex as perf_install_in_context() */
4146 static bool exclusive_event_installable(struct perf_event *event,
4147 struct perf_event_context *ctx)
4149 struct perf_event *iter_event;
4150 struct pmu *pmu = event->pmu;
4152 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4155 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4156 if (exclusive_event_match(iter_event, event))
4163 static void perf_addr_filters_splice(struct perf_event *event,
4164 struct list_head *head);
4166 static void _free_event(struct perf_event *event)
4168 irq_work_sync(&event->pending);
4170 unaccount_event(event);
4174 * Can happen when we close an event with re-directed output.
4176 * Since we have a 0 refcount, perf_mmap_close() will skip
4177 * over us; possibly making our ring_buffer_put() the last.
4179 mutex_lock(&event->mmap_mutex);
4180 ring_buffer_attach(event, NULL);
4181 mutex_unlock(&event->mmap_mutex);
4184 if (is_cgroup_event(event))
4185 perf_detach_cgroup(event);
4187 if (!event->parent) {
4188 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4189 put_callchain_buffers();
4192 perf_event_free_bpf_prog(event);
4193 perf_addr_filters_splice(event, NULL);
4194 kfree(event->addr_filters_offs);
4197 event->destroy(event);
4200 put_ctx(event->ctx);
4202 exclusive_event_destroy(event);
4203 module_put(event->pmu->module);
4205 call_rcu(&event->rcu_head, free_event_rcu);
4209 * Used to free events which have a known refcount of 1, such as in error paths
4210 * where the event isn't exposed yet and inherited events.
4212 static void free_event(struct perf_event *event)
4214 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4215 "unexpected event refcount: %ld; ptr=%p\n",
4216 atomic_long_read(&event->refcount), event)) {
4217 /* leak to avoid use-after-free */
4225 * Remove user event from the owner task.
4227 static void perf_remove_from_owner(struct perf_event *event)
4229 struct task_struct *owner;
4233 * Matches the smp_store_release() in perf_event_exit_task(). If we
4234 * observe !owner it means the list deletion is complete and we can
4235 * indeed free this event, otherwise we need to serialize on
4236 * owner->perf_event_mutex.
4238 owner = READ_ONCE(event->owner);
4241 * Since delayed_put_task_struct() also drops the last
4242 * task reference we can safely take a new reference
4243 * while holding the rcu_read_lock().
4245 get_task_struct(owner);
4251 * If we're here through perf_event_exit_task() we're already
4252 * holding ctx->mutex which would be an inversion wrt. the
4253 * normal lock order.
4255 * However we can safely take this lock because its the child
4258 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4261 * We have to re-check the event->owner field, if it is cleared
4262 * we raced with perf_event_exit_task(), acquiring the mutex
4263 * ensured they're done, and we can proceed with freeing the
4267 list_del_init(&event->owner_entry);
4268 smp_store_release(&event->owner, NULL);
4270 mutex_unlock(&owner->perf_event_mutex);
4271 put_task_struct(owner);
4275 static void put_event(struct perf_event *event)
4277 if (!atomic_long_dec_and_test(&event->refcount))
4284 * Kill an event dead; while event:refcount will preserve the event
4285 * object, it will not preserve its functionality. Once the last 'user'
4286 * gives up the object, we'll destroy the thing.
4288 int perf_event_release_kernel(struct perf_event *event)
4290 struct perf_event_context *ctx = event->ctx;
4291 struct perf_event *child, *tmp;
4294 * If we got here through err_file: fput(event_file); we will not have
4295 * attached to a context yet.
4298 WARN_ON_ONCE(event->attach_state &
4299 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4303 if (!is_kernel_event(event))
4304 perf_remove_from_owner(event);
4306 ctx = perf_event_ctx_lock(event);
4307 WARN_ON_ONCE(ctx->parent_ctx);
4308 perf_remove_from_context(event, DETACH_GROUP);
4310 raw_spin_lock_irq(&ctx->lock);
4312 * Mark this event as STATE_DEAD, there is no external reference to it
4315 * Anybody acquiring event->child_mutex after the below loop _must_
4316 * also see this, most importantly inherit_event() which will avoid
4317 * placing more children on the list.
4319 * Thus this guarantees that we will in fact observe and kill _ALL_
4322 event->state = PERF_EVENT_STATE_DEAD;
4323 raw_spin_unlock_irq(&ctx->lock);
4325 perf_event_ctx_unlock(event, ctx);
4328 mutex_lock(&event->child_mutex);
4329 list_for_each_entry(child, &event->child_list, child_list) {
4332 * Cannot change, child events are not migrated, see the
4333 * comment with perf_event_ctx_lock_nested().
4335 ctx = READ_ONCE(child->ctx);
4337 * Since child_mutex nests inside ctx::mutex, we must jump
4338 * through hoops. We start by grabbing a reference on the ctx.
4340 * Since the event cannot get freed while we hold the
4341 * child_mutex, the context must also exist and have a !0
4347 * Now that we have a ctx ref, we can drop child_mutex, and
4348 * acquire ctx::mutex without fear of it going away. Then we
4349 * can re-acquire child_mutex.
4351 mutex_unlock(&event->child_mutex);
4352 mutex_lock(&ctx->mutex);
4353 mutex_lock(&event->child_mutex);
4356 * Now that we hold ctx::mutex and child_mutex, revalidate our
4357 * state, if child is still the first entry, it didn't get freed
4358 * and we can continue doing so.
4360 tmp = list_first_entry_or_null(&event->child_list,
4361 struct perf_event, child_list);
4363 perf_remove_from_context(child, DETACH_GROUP);
4364 list_del(&child->child_list);
4367 * This matches the refcount bump in inherit_event();
4368 * this can't be the last reference.
4373 mutex_unlock(&event->child_mutex);
4374 mutex_unlock(&ctx->mutex);
4378 mutex_unlock(&event->child_mutex);
4381 put_event(event); /* Must be the 'last' reference */
4384 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4387 * Called when the last reference to the file is gone.
4389 static int perf_release(struct inode *inode, struct file *file)
4391 perf_event_release_kernel(file->private_data);
4395 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4397 struct perf_event *child;
4403 mutex_lock(&event->child_mutex);
4405 (void)perf_event_read(event, false);
4406 total += perf_event_count(event);
4408 *enabled += event->total_time_enabled +
4409 atomic64_read(&event->child_total_time_enabled);
4410 *running += event->total_time_running +
4411 atomic64_read(&event->child_total_time_running);
4413 list_for_each_entry(child, &event->child_list, child_list) {
4414 (void)perf_event_read(child, false);
4415 total += perf_event_count(child);
4416 *enabled += child->total_time_enabled;
4417 *running += child->total_time_running;
4419 mutex_unlock(&event->child_mutex);
4423 EXPORT_SYMBOL_GPL(perf_event_read_value);
4425 static int __perf_read_group_add(struct perf_event *leader,
4426 u64 read_format, u64 *values)
4428 struct perf_event_context *ctx = leader->ctx;
4429 struct perf_event *sub;
4430 unsigned long flags;
4431 int n = 1; /* skip @nr */
4434 ret = perf_event_read(leader, true);
4438 raw_spin_lock_irqsave(&ctx->lock, flags);
4441 * Since we co-schedule groups, {enabled,running} times of siblings
4442 * will be identical to those of the leader, so we only publish one
4445 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4446 values[n++] += leader->total_time_enabled +
4447 atomic64_read(&leader->child_total_time_enabled);
4450 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4451 values[n++] += leader->total_time_running +
4452 atomic64_read(&leader->child_total_time_running);
4456 * Write {count,id} tuples for every sibling.
4458 values[n++] += perf_event_count(leader);
4459 if (read_format & PERF_FORMAT_ID)
4460 values[n++] = primary_event_id(leader);
4462 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4463 values[n++] += perf_event_count(sub);
4464 if (read_format & PERF_FORMAT_ID)
4465 values[n++] = primary_event_id(sub);
4468 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4472 static int perf_read_group(struct perf_event *event,
4473 u64 read_format, char __user *buf)
4475 struct perf_event *leader = event->group_leader, *child;
4476 struct perf_event_context *ctx = leader->ctx;
4480 lockdep_assert_held(&ctx->mutex);
4482 values = kzalloc(event->read_size, GFP_KERNEL);
4486 values[0] = 1 + leader->nr_siblings;
4489 * By locking the child_mutex of the leader we effectively
4490 * lock the child list of all siblings.. XXX explain how.
4492 mutex_lock(&leader->child_mutex);
4494 ret = __perf_read_group_add(leader, read_format, values);
4498 list_for_each_entry(child, &leader->child_list, child_list) {
4499 ret = __perf_read_group_add(child, read_format, values);
4504 mutex_unlock(&leader->child_mutex);
4506 ret = event->read_size;
4507 if (copy_to_user(buf, values, event->read_size))
4512 mutex_unlock(&leader->child_mutex);
4518 static int perf_read_one(struct perf_event *event,
4519 u64 read_format, char __user *buf)
4521 u64 enabled, running;
4525 values[n++] = perf_event_read_value(event, &enabled, &running);
4526 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4527 values[n++] = enabled;
4528 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4529 values[n++] = running;
4530 if (read_format & PERF_FORMAT_ID)
4531 values[n++] = primary_event_id(event);
4533 if (copy_to_user(buf, values, n * sizeof(u64)))
4536 return n * sizeof(u64);
4539 static bool is_event_hup(struct perf_event *event)
4543 if (event->state > PERF_EVENT_STATE_EXIT)
4546 mutex_lock(&event->child_mutex);
4547 no_children = list_empty(&event->child_list);
4548 mutex_unlock(&event->child_mutex);
4553 * Read the performance event - simple non blocking version for now
4556 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4558 u64 read_format = event->attr.read_format;
4562 * Return end-of-file for a read on a event that is in
4563 * error state (i.e. because it was pinned but it couldn't be
4564 * scheduled on to the CPU at some point).
4566 if (event->state == PERF_EVENT_STATE_ERROR)
4569 if (count < event->read_size)
4572 WARN_ON_ONCE(event->ctx->parent_ctx);
4573 if (read_format & PERF_FORMAT_GROUP)
4574 ret = perf_read_group(event, read_format, buf);
4576 ret = perf_read_one(event, read_format, buf);
4582 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4584 struct perf_event *event = file->private_data;
4585 struct perf_event_context *ctx;
4588 ctx = perf_event_ctx_lock(event);
4589 ret = __perf_read(event, buf, count);
4590 perf_event_ctx_unlock(event, ctx);
4595 static unsigned int perf_poll(struct file *file, poll_table *wait)
4597 struct perf_event *event = file->private_data;
4598 struct ring_buffer *rb;
4599 unsigned int events = POLLHUP;
4601 poll_wait(file, &event->waitq, wait);
4603 if (is_event_hup(event))
4607 * Pin the event->rb by taking event->mmap_mutex; otherwise
4608 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4610 mutex_lock(&event->mmap_mutex);
4613 events = atomic_xchg(&rb->poll, 0);
4614 mutex_unlock(&event->mmap_mutex);
4618 static void _perf_event_reset(struct perf_event *event)
4620 (void)perf_event_read(event, false);
4621 local64_set(&event->count, 0);
4622 perf_event_update_userpage(event);
4626 * Holding the top-level event's child_mutex means that any
4627 * descendant process that has inherited this event will block
4628 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4629 * task existence requirements of perf_event_enable/disable.
4631 static void perf_event_for_each_child(struct perf_event *event,
4632 void (*func)(struct perf_event *))
4634 struct perf_event *child;
4636 WARN_ON_ONCE(event->ctx->parent_ctx);
4638 mutex_lock(&event->child_mutex);
4640 list_for_each_entry(child, &event->child_list, child_list)
4642 mutex_unlock(&event->child_mutex);
4645 static void perf_event_for_each(struct perf_event *event,
4646 void (*func)(struct perf_event *))
4648 struct perf_event_context *ctx = event->ctx;
4649 struct perf_event *sibling;
4651 lockdep_assert_held(&ctx->mutex);
4653 event = event->group_leader;
4655 perf_event_for_each_child(event, func);
4656 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4657 perf_event_for_each_child(sibling, func);
4660 static void __perf_event_period(struct perf_event *event,
4661 struct perf_cpu_context *cpuctx,
4662 struct perf_event_context *ctx,
4665 u64 value = *((u64 *)info);
4668 if (event->attr.freq) {
4669 event->attr.sample_freq = value;
4671 event->attr.sample_period = value;
4672 event->hw.sample_period = value;
4675 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4677 perf_pmu_disable(ctx->pmu);
4679 * We could be throttled; unthrottle now to avoid the tick
4680 * trying to unthrottle while we already re-started the event.
4682 if (event->hw.interrupts == MAX_INTERRUPTS) {
4683 event->hw.interrupts = 0;
4684 perf_log_throttle(event, 1);
4686 event->pmu->stop(event, PERF_EF_UPDATE);
4689 local64_set(&event->hw.period_left, 0);
4692 event->pmu->start(event, PERF_EF_RELOAD);
4693 perf_pmu_enable(ctx->pmu);
4697 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4701 if (!is_sampling_event(event))
4704 if (copy_from_user(&value, arg, sizeof(value)))
4710 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4713 event_function_call(event, __perf_event_period, &value);
4718 static const struct file_operations perf_fops;
4720 static inline int perf_fget_light(int fd, struct fd *p)
4722 struct fd f = fdget(fd);
4726 if (f.file->f_op != &perf_fops) {
4734 static int perf_event_set_output(struct perf_event *event,
4735 struct perf_event *output_event);
4736 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4737 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4739 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4741 void (*func)(struct perf_event *);
4745 case PERF_EVENT_IOC_ENABLE:
4746 func = _perf_event_enable;
4748 case PERF_EVENT_IOC_DISABLE:
4749 func = _perf_event_disable;
4751 case PERF_EVENT_IOC_RESET:
4752 func = _perf_event_reset;
4755 case PERF_EVENT_IOC_REFRESH:
4756 return _perf_event_refresh(event, arg);
4758 case PERF_EVENT_IOC_PERIOD:
4759 return perf_event_period(event, (u64 __user *)arg);
4761 case PERF_EVENT_IOC_ID:
4763 u64 id = primary_event_id(event);
4765 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4770 case PERF_EVENT_IOC_SET_OUTPUT:
4774 struct perf_event *output_event;
4776 ret = perf_fget_light(arg, &output);
4779 output_event = output.file->private_data;
4780 ret = perf_event_set_output(event, output_event);
4783 ret = perf_event_set_output(event, NULL);
4788 case PERF_EVENT_IOC_SET_FILTER:
4789 return perf_event_set_filter(event, (void __user *)arg);
4791 case PERF_EVENT_IOC_SET_BPF:
4792 return perf_event_set_bpf_prog(event, arg);
4794 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4795 struct ring_buffer *rb;
4798 rb = rcu_dereference(event->rb);
4799 if (!rb || !rb->nr_pages) {
4803 rb_toggle_paused(rb, !!arg);
4811 if (flags & PERF_IOC_FLAG_GROUP)
4812 perf_event_for_each(event, func);
4814 perf_event_for_each_child(event, func);
4819 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4821 struct perf_event *event = file->private_data;
4822 struct perf_event_context *ctx;
4825 ctx = perf_event_ctx_lock(event);
4826 ret = _perf_ioctl(event, cmd, arg);
4827 perf_event_ctx_unlock(event, ctx);
4832 #ifdef CONFIG_COMPAT
4833 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4836 switch (_IOC_NR(cmd)) {
4837 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4838 case _IOC_NR(PERF_EVENT_IOC_ID):
4839 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4840 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4841 cmd &= ~IOCSIZE_MASK;
4842 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4846 return perf_ioctl(file, cmd, arg);
4849 # define perf_compat_ioctl NULL
4852 int perf_event_task_enable(void)
4854 struct perf_event_context *ctx;
4855 struct perf_event *event;
4857 mutex_lock(¤t->perf_event_mutex);
4858 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4859 ctx = perf_event_ctx_lock(event);
4860 perf_event_for_each_child(event, _perf_event_enable);
4861 perf_event_ctx_unlock(event, ctx);
4863 mutex_unlock(¤t->perf_event_mutex);
4868 int perf_event_task_disable(void)
4870 struct perf_event_context *ctx;
4871 struct perf_event *event;
4873 mutex_lock(¤t->perf_event_mutex);
4874 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4875 ctx = perf_event_ctx_lock(event);
4876 perf_event_for_each_child(event, _perf_event_disable);
4877 perf_event_ctx_unlock(event, ctx);
4879 mutex_unlock(¤t->perf_event_mutex);
4884 static int perf_event_index(struct perf_event *event)
4886 if (event->hw.state & PERF_HES_STOPPED)
4889 if (event->state != PERF_EVENT_STATE_ACTIVE)
4892 return event->pmu->event_idx(event);
4895 static void calc_timer_values(struct perf_event *event,
4902 *now = perf_clock();
4903 ctx_time = event->shadow_ctx_time + *now;
4904 *enabled = ctx_time - event->tstamp_enabled;
4905 *running = ctx_time - event->tstamp_running;
4908 static void perf_event_init_userpage(struct perf_event *event)
4910 struct perf_event_mmap_page *userpg;
4911 struct ring_buffer *rb;
4914 rb = rcu_dereference(event->rb);
4918 userpg = rb->user_page;
4920 /* Allow new userspace to detect that bit 0 is deprecated */
4921 userpg->cap_bit0_is_deprecated = 1;
4922 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4923 userpg->data_offset = PAGE_SIZE;
4924 userpg->data_size = perf_data_size(rb);
4930 void __weak arch_perf_update_userpage(
4931 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4936 * Callers need to ensure there can be no nesting of this function, otherwise
4937 * the seqlock logic goes bad. We can not serialize this because the arch
4938 * code calls this from NMI context.
4940 void perf_event_update_userpage(struct perf_event *event)
4942 struct perf_event_mmap_page *userpg;
4943 struct ring_buffer *rb;
4944 u64 enabled, running, now;
4947 rb = rcu_dereference(event->rb);
4952 * compute total_time_enabled, total_time_running
4953 * based on snapshot values taken when the event
4954 * was last scheduled in.
4956 * we cannot simply called update_context_time()
4957 * because of locking issue as we can be called in
4960 calc_timer_values(event, &now, &enabled, &running);
4962 userpg = rb->user_page;
4964 * Disable preemption so as to not let the corresponding user-space
4965 * spin too long if we get preempted.
4970 userpg->index = perf_event_index(event);
4971 userpg->offset = perf_event_count(event);
4973 userpg->offset -= local64_read(&event->hw.prev_count);
4975 userpg->time_enabled = enabled +
4976 atomic64_read(&event->child_total_time_enabled);
4978 userpg->time_running = running +
4979 atomic64_read(&event->child_total_time_running);
4981 arch_perf_update_userpage(event, userpg, now);
4990 static int perf_mmap_fault(struct vm_fault *vmf)
4992 struct perf_event *event = vmf->vma->vm_file->private_data;
4993 struct ring_buffer *rb;
4994 int ret = VM_FAULT_SIGBUS;
4996 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4997 if (vmf->pgoff == 0)
5003 rb = rcu_dereference(event->rb);
5007 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5010 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5014 get_page(vmf->page);
5015 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5016 vmf->page->index = vmf->pgoff;
5025 static void ring_buffer_attach(struct perf_event *event,
5026 struct ring_buffer *rb)
5028 struct ring_buffer *old_rb = NULL;
5029 unsigned long flags;
5033 * Should be impossible, we set this when removing
5034 * event->rb_entry and wait/clear when adding event->rb_entry.
5036 WARN_ON_ONCE(event->rcu_pending);
5039 spin_lock_irqsave(&old_rb->event_lock, flags);
5040 list_del_rcu(&event->rb_entry);
5041 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5043 event->rcu_batches = get_state_synchronize_rcu();
5044 event->rcu_pending = 1;
5048 if (event->rcu_pending) {
5049 cond_synchronize_rcu(event->rcu_batches);
5050 event->rcu_pending = 0;
5053 spin_lock_irqsave(&rb->event_lock, flags);
5054 list_add_rcu(&event->rb_entry, &rb->event_list);
5055 spin_unlock_irqrestore(&rb->event_lock, flags);
5059 * Avoid racing with perf_mmap_close(AUX): stop the event
5060 * before swizzling the event::rb pointer; if it's getting
5061 * unmapped, its aux_mmap_count will be 0 and it won't
5062 * restart. See the comment in __perf_pmu_output_stop().
5064 * Data will inevitably be lost when set_output is done in
5065 * mid-air, but then again, whoever does it like this is
5066 * not in for the data anyway.
5069 perf_event_stop(event, 0);
5071 rcu_assign_pointer(event->rb, rb);
5074 ring_buffer_put(old_rb);
5076 * Since we detached before setting the new rb, so that we
5077 * could attach the new rb, we could have missed a wakeup.
5080 wake_up_all(&event->waitq);
5084 static void ring_buffer_wakeup(struct perf_event *event)
5086 struct ring_buffer *rb;
5089 rb = rcu_dereference(event->rb);
5091 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5092 wake_up_all(&event->waitq);
5097 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5099 struct ring_buffer *rb;
5102 rb = rcu_dereference(event->rb);
5104 if (!atomic_inc_not_zero(&rb->refcount))
5112 void ring_buffer_put(struct ring_buffer *rb)
5114 if (!atomic_dec_and_test(&rb->refcount))
5117 WARN_ON_ONCE(!list_empty(&rb->event_list));
5119 call_rcu(&rb->rcu_head, rb_free_rcu);
5122 static void perf_mmap_open(struct vm_area_struct *vma)
5124 struct perf_event *event = vma->vm_file->private_data;
5126 atomic_inc(&event->mmap_count);
5127 atomic_inc(&event->rb->mmap_count);
5130 atomic_inc(&event->rb->aux_mmap_count);
5132 if (event->pmu->event_mapped)
5133 event->pmu->event_mapped(event, vma->vm_mm);
5136 static void perf_pmu_output_stop(struct perf_event *event);
5139 * A buffer can be mmap()ed multiple times; either directly through the same
5140 * event, or through other events by use of perf_event_set_output().
5142 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5143 * the buffer here, where we still have a VM context. This means we need
5144 * to detach all events redirecting to us.
5146 static void perf_mmap_close(struct vm_area_struct *vma)
5148 struct perf_event *event = vma->vm_file->private_data;
5150 struct ring_buffer *rb = ring_buffer_get(event);
5151 struct user_struct *mmap_user = rb->mmap_user;
5152 int mmap_locked = rb->mmap_locked;
5153 unsigned long size = perf_data_size(rb);
5155 if (event->pmu->event_unmapped)
5156 event->pmu->event_unmapped(event, vma->vm_mm);
5159 * rb->aux_mmap_count will always drop before rb->mmap_count and
5160 * event->mmap_count, so it is ok to use event->mmap_mutex to
5161 * serialize with perf_mmap here.
5163 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5164 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5166 * Stop all AUX events that are writing to this buffer,
5167 * so that we can free its AUX pages and corresponding PMU
5168 * data. Note that after rb::aux_mmap_count dropped to zero,
5169 * they won't start any more (see perf_aux_output_begin()).
5171 perf_pmu_output_stop(event);
5173 /* now it's safe to free the pages */
5174 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5175 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5177 /* this has to be the last one */
5179 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5181 mutex_unlock(&event->mmap_mutex);
5184 atomic_dec(&rb->mmap_count);
5186 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5189 ring_buffer_attach(event, NULL);
5190 mutex_unlock(&event->mmap_mutex);
5192 /* If there's still other mmap()s of this buffer, we're done. */
5193 if (atomic_read(&rb->mmap_count))
5197 * No other mmap()s, detach from all other events that might redirect
5198 * into the now unreachable buffer. Somewhat complicated by the
5199 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5203 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5204 if (!atomic_long_inc_not_zero(&event->refcount)) {
5206 * This event is en-route to free_event() which will
5207 * detach it and remove it from the list.
5213 mutex_lock(&event->mmap_mutex);
5215 * Check we didn't race with perf_event_set_output() which can
5216 * swizzle the rb from under us while we were waiting to
5217 * acquire mmap_mutex.
5219 * If we find a different rb; ignore this event, a next
5220 * iteration will no longer find it on the list. We have to
5221 * still restart the iteration to make sure we're not now
5222 * iterating the wrong list.
5224 if (event->rb == rb)
5225 ring_buffer_attach(event, NULL);
5227 mutex_unlock(&event->mmap_mutex);
5231 * Restart the iteration; either we're on the wrong list or
5232 * destroyed its integrity by doing a deletion.
5239 * It could be there's still a few 0-ref events on the list; they'll
5240 * get cleaned up by free_event() -- they'll also still have their
5241 * ref on the rb and will free it whenever they are done with it.
5243 * Aside from that, this buffer is 'fully' detached and unmapped,
5244 * undo the VM accounting.
5247 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5248 vma->vm_mm->pinned_vm -= mmap_locked;
5249 free_uid(mmap_user);
5252 ring_buffer_put(rb); /* could be last */
5255 static const struct vm_operations_struct perf_mmap_vmops = {
5256 .open = perf_mmap_open,
5257 .close = perf_mmap_close, /* non mergable */
5258 .fault = perf_mmap_fault,
5259 .page_mkwrite = perf_mmap_fault,
5262 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5264 struct perf_event *event = file->private_data;
5265 unsigned long user_locked, user_lock_limit;
5266 struct user_struct *user = current_user();
5267 unsigned long locked, lock_limit;
5268 struct ring_buffer *rb = NULL;
5269 unsigned long vma_size;
5270 unsigned long nr_pages;
5271 long user_extra = 0, extra = 0;
5272 int ret = 0, flags = 0;
5275 * Don't allow mmap() of inherited per-task counters. This would
5276 * create a performance issue due to all children writing to the
5279 if (event->cpu == -1 && event->attr.inherit)
5282 if (!(vma->vm_flags & VM_SHARED))
5285 vma_size = vma->vm_end - vma->vm_start;
5287 if (vma->vm_pgoff == 0) {
5288 nr_pages = (vma_size / PAGE_SIZE) - 1;
5291 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5292 * mapped, all subsequent mappings should have the same size
5293 * and offset. Must be above the normal perf buffer.
5295 u64 aux_offset, aux_size;
5300 nr_pages = vma_size / PAGE_SIZE;
5302 mutex_lock(&event->mmap_mutex);
5309 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5310 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5312 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5315 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5318 /* already mapped with a different offset */
5319 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5322 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5325 /* already mapped with a different size */
5326 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5329 if (!is_power_of_2(nr_pages))
5332 if (!atomic_inc_not_zero(&rb->mmap_count))
5335 if (rb_has_aux(rb)) {
5336 atomic_inc(&rb->aux_mmap_count);
5341 atomic_set(&rb->aux_mmap_count, 1);
5342 user_extra = nr_pages;
5348 * If we have rb pages ensure they're a power-of-two number, so we
5349 * can do bitmasks instead of modulo.
5351 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5354 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5357 WARN_ON_ONCE(event->ctx->parent_ctx);
5359 mutex_lock(&event->mmap_mutex);
5361 if (event->rb->nr_pages != nr_pages) {
5366 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5368 * Raced against perf_mmap_close() through
5369 * perf_event_set_output(). Try again, hope for better
5372 mutex_unlock(&event->mmap_mutex);
5379 user_extra = nr_pages + 1;
5382 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5385 * Increase the limit linearly with more CPUs:
5387 user_lock_limit *= num_online_cpus();
5389 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5391 if (user_locked > user_lock_limit)
5392 extra = user_locked - user_lock_limit;
5394 lock_limit = rlimit(RLIMIT_MEMLOCK);
5395 lock_limit >>= PAGE_SHIFT;
5396 locked = vma->vm_mm->pinned_vm + extra;
5398 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5399 !capable(CAP_IPC_LOCK)) {
5404 WARN_ON(!rb && event->rb);
5406 if (vma->vm_flags & VM_WRITE)
5407 flags |= RING_BUFFER_WRITABLE;
5410 rb = rb_alloc(nr_pages,
5411 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5419 atomic_set(&rb->mmap_count, 1);
5420 rb->mmap_user = get_current_user();
5421 rb->mmap_locked = extra;
5423 ring_buffer_attach(event, rb);
5425 perf_event_init_userpage(event);
5426 perf_event_update_userpage(event);
5428 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5429 event->attr.aux_watermark, flags);
5431 rb->aux_mmap_locked = extra;
5436 atomic_long_add(user_extra, &user->locked_vm);
5437 vma->vm_mm->pinned_vm += extra;
5439 atomic_inc(&event->mmap_count);
5441 atomic_dec(&rb->mmap_count);
5444 mutex_unlock(&event->mmap_mutex);
5447 * Since pinned accounting is per vm we cannot allow fork() to copy our
5450 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5451 vma->vm_ops = &perf_mmap_vmops;
5453 if (event->pmu->event_mapped)
5454 event->pmu->event_mapped(event, vma->vm_mm);
5459 static int perf_fasync(int fd, struct file *filp, int on)
5461 struct inode *inode = file_inode(filp);
5462 struct perf_event *event = filp->private_data;
5466 retval = fasync_helper(fd, filp, on, &event->fasync);
5467 inode_unlock(inode);
5475 static const struct file_operations perf_fops = {
5476 .llseek = no_llseek,
5477 .release = perf_release,
5480 .unlocked_ioctl = perf_ioctl,
5481 .compat_ioctl = perf_compat_ioctl,
5483 .fasync = perf_fasync,
5489 * If there's data, ensure we set the poll() state and publish everything
5490 * to user-space before waking everybody up.
5493 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5495 /* only the parent has fasync state */
5497 event = event->parent;
5498 return &event->fasync;
5501 void perf_event_wakeup(struct perf_event *event)
5503 ring_buffer_wakeup(event);
5505 if (event->pending_kill) {
5506 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5507 event->pending_kill = 0;
5511 static void perf_pending_event(struct irq_work *entry)
5513 struct perf_event *event = container_of(entry,
5514 struct perf_event, pending);
5517 rctx = perf_swevent_get_recursion_context();
5519 * If we 'fail' here, that's OK, it means recursion is already disabled
5520 * and we won't recurse 'further'.
5523 if (event->pending_disable) {
5524 event->pending_disable = 0;
5525 perf_event_disable_local(event);
5528 if (event->pending_wakeup) {
5529 event->pending_wakeup = 0;
5530 perf_event_wakeup(event);
5534 perf_swevent_put_recursion_context(rctx);
5538 * We assume there is only KVM supporting the callbacks.
5539 * Later on, we might change it to a list if there is
5540 * another virtualization implementation supporting the callbacks.
5542 struct perf_guest_info_callbacks *perf_guest_cbs;
5544 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5546 perf_guest_cbs = cbs;
5549 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5551 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5553 perf_guest_cbs = NULL;
5556 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5559 perf_output_sample_regs(struct perf_output_handle *handle,
5560 struct pt_regs *regs, u64 mask)
5563 DECLARE_BITMAP(_mask, 64);
5565 bitmap_from_u64(_mask, mask);
5566 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5569 val = perf_reg_value(regs, bit);
5570 perf_output_put(handle, val);
5574 static void perf_sample_regs_user(struct perf_regs *regs_user,
5575 struct pt_regs *regs,
5576 struct pt_regs *regs_user_copy)
5578 if (user_mode(regs)) {
5579 regs_user->abi = perf_reg_abi(current);
5580 regs_user->regs = regs;
5581 } else if (current->mm) {
5582 perf_get_regs_user(regs_user, regs, regs_user_copy);
5584 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5585 regs_user->regs = NULL;
5589 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5590 struct pt_regs *regs)
5592 regs_intr->regs = regs;
5593 regs_intr->abi = perf_reg_abi(current);
5598 * Get remaining task size from user stack pointer.
5600 * It'd be better to take stack vma map and limit this more
5601 * precisly, but there's no way to get it safely under interrupt,
5602 * so using TASK_SIZE as limit.
5604 static u64 perf_ustack_task_size(struct pt_regs *regs)
5606 unsigned long addr = perf_user_stack_pointer(regs);
5608 if (!addr || addr >= TASK_SIZE)
5611 return TASK_SIZE - addr;
5615 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5616 struct pt_regs *regs)
5620 /* No regs, no stack pointer, no dump. */
5625 * Check if we fit in with the requested stack size into the:
5627 * If we don't, we limit the size to the TASK_SIZE.
5629 * - remaining sample size
5630 * If we don't, we customize the stack size to
5631 * fit in to the remaining sample size.
5634 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5635 stack_size = min(stack_size, (u16) task_size);
5637 /* Current header size plus static size and dynamic size. */
5638 header_size += 2 * sizeof(u64);
5640 /* Do we fit in with the current stack dump size? */
5641 if ((u16) (header_size + stack_size) < header_size) {
5643 * If we overflow the maximum size for the sample,
5644 * we customize the stack dump size to fit in.
5646 stack_size = USHRT_MAX - header_size - sizeof(u64);
5647 stack_size = round_up(stack_size, sizeof(u64));
5654 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5655 struct pt_regs *regs)
5657 /* Case of a kernel thread, nothing to dump */
5660 perf_output_put(handle, size);
5669 * - the size requested by user or the best one we can fit
5670 * in to the sample max size
5672 * - user stack dump data
5674 * - the actual dumped size
5678 perf_output_put(handle, dump_size);
5681 sp = perf_user_stack_pointer(regs);
5682 rem = __output_copy_user(handle, (void *) sp, dump_size);
5683 dyn_size = dump_size - rem;
5685 perf_output_skip(handle, rem);
5688 perf_output_put(handle, dyn_size);
5692 static void __perf_event_header__init_id(struct perf_event_header *header,
5693 struct perf_sample_data *data,
5694 struct perf_event *event)
5696 u64 sample_type = event->attr.sample_type;
5698 data->type = sample_type;
5699 header->size += event->id_header_size;
5701 if (sample_type & PERF_SAMPLE_TID) {
5702 /* namespace issues */
5703 data->tid_entry.pid = perf_event_pid(event, current);
5704 data->tid_entry.tid = perf_event_tid(event, current);
5707 if (sample_type & PERF_SAMPLE_TIME)
5708 data->time = perf_event_clock(event);
5710 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5711 data->id = primary_event_id(event);
5713 if (sample_type & PERF_SAMPLE_STREAM_ID)
5714 data->stream_id = event->id;
5716 if (sample_type & PERF_SAMPLE_CPU) {
5717 data->cpu_entry.cpu = raw_smp_processor_id();
5718 data->cpu_entry.reserved = 0;
5722 void perf_event_header__init_id(struct perf_event_header *header,
5723 struct perf_sample_data *data,
5724 struct perf_event *event)
5726 if (event->attr.sample_id_all)
5727 __perf_event_header__init_id(header, data, event);
5730 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5731 struct perf_sample_data *data)
5733 u64 sample_type = data->type;
5735 if (sample_type & PERF_SAMPLE_TID)
5736 perf_output_put(handle, data->tid_entry);
5738 if (sample_type & PERF_SAMPLE_TIME)
5739 perf_output_put(handle, data->time);
5741 if (sample_type & PERF_SAMPLE_ID)
5742 perf_output_put(handle, data->id);
5744 if (sample_type & PERF_SAMPLE_STREAM_ID)
5745 perf_output_put(handle, data->stream_id);
5747 if (sample_type & PERF_SAMPLE_CPU)
5748 perf_output_put(handle, data->cpu_entry);
5750 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5751 perf_output_put(handle, data->id);
5754 void perf_event__output_id_sample(struct perf_event *event,
5755 struct perf_output_handle *handle,
5756 struct perf_sample_data *sample)
5758 if (event->attr.sample_id_all)
5759 __perf_event__output_id_sample(handle, sample);
5762 static void perf_output_read_one(struct perf_output_handle *handle,
5763 struct perf_event *event,
5764 u64 enabled, u64 running)
5766 u64 read_format = event->attr.read_format;
5770 values[n++] = perf_event_count(event);
5771 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5772 values[n++] = enabled +
5773 atomic64_read(&event->child_total_time_enabled);
5775 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5776 values[n++] = running +
5777 atomic64_read(&event->child_total_time_running);
5779 if (read_format & PERF_FORMAT_ID)
5780 values[n++] = primary_event_id(event);
5782 __output_copy(handle, values, n * sizeof(u64));
5785 static void perf_output_read_group(struct perf_output_handle *handle,
5786 struct perf_event *event,
5787 u64 enabled, u64 running)
5789 struct perf_event *leader = event->group_leader, *sub;
5790 u64 read_format = event->attr.read_format;
5794 values[n++] = 1 + leader->nr_siblings;
5796 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5797 values[n++] = enabled;
5799 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5800 values[n++] = running;
5802 if (leader != event)
5803 leader->pmu->read(leader);
5805 values[n++] = perf_event_count(leader);
5806 if (read_format & PERF_FORMAT_ID)
5807 values[n++] = primary_event_id(leader);
5809 __output_copy(handle, values, n * sizeof(u64));
5811 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5814 if ((sub != event) &&
5815 (sub->state == PERF_EVENT_STATE_ACTIVE))
5816 sub->pmu->read(sub);
5818 values[n++] = perf_event_count(sub);
5819 if (read_format & PERF_FORMAT_ID)
5820 values[n++] = primary_event_id(sub);
5822 __output_copy(handle, values, n * sizeof(u64));
5826 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5827 PERF_FORMAT_TOTAL_TIME_RUNNING)
5830 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5832 * The problem is that its both hard and excessively expensive to iterate the
5833 * child list, not to mention that its impossible to IPI the children running
5834 * on another CPU, from interrupt/NMI context.
5836 static void perf_output_read(struct perf_output_handle *handle,
5837 struct perf_event *event)
5839 u64 enabled = 0, running = 0, now;
5840 u64 read_format = event->attr.read_format;
5843 * compute total_time_enabled, total_time_running
5844 * based on snapshot values taken when the event
5845 * was last scheduled in.
5847 * we cannot simply called update_context_time()
5848 * because of locking issue as we are called in
5851 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5852 calc_timer_values(event, &now, &enabled, &running);
5854 if (event->attr.read_format & PERF_FORMAT_GROUP)
5855 perf_output_read_group(handle, event, enabled, running);
5857 perf_output_read_one(handle, event, enabled, running);
5860 void perf_output_sample(struct perf_output_handle *handle,
5861 struct perf_event_header *header,
5862 struct perf_sample_data *data,
5863 struct perf_event *event)
5865 u64 sample_type = data->type;
5867 perf_output_put(handle, *header);
5869 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5870 perf_output_put(handle, data->id);
5872 if (sample_type & PERF_SAMPLE_IP)
5873 perf_output_put(handle, data->ip);
5875 if (sample_type & PERF_SAMPLE_TID)
5876 perf_output_put(handle, data->tid_entry);
5878 if (sample_type & PERF_SAMPLE_TIME)
5879 perf_output_put(handle, data->time);
5881 if (sample_type & PERF_SAMPLE_ADDR)
5882 perf_output_put(handle, data->addr);
5884 if (sample_type & PERF_SAMPLE_ID)
5885 perf_output_put(handle, data->id);
5887 if (sample_type & PERF_SAMPLE_STREAM_ID)
5888 perf_output_put(handle, data->stream_id);
5890 if (sample_type & PERF_SAMPLE_CPU)
5891 perf_output_put(handle, data->cpu_entry);
5893 if (sample_type & PERF_SAMPLE_PERIOD)
5894 perf_output_put(handle, data->period);
5896 if (sample_type & PERF_SAMPLE_READ)
5897 perf_output_read(handle, event);
5899 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5900 if (data->callchain) {
5903 if (data->callchain)
5904 size += data->callchain->nr;
5906 size *= sizeof(u64);
5908 __output_copy(handle, data->callchain, size);
5911 perf_output_put(handle, nr);
5915 if (sample_type & PERF_SAMPLE_RAW) {
5916 struct perf_raw_record *raw = data->raw;
5919 struct perf_raw_frag *frag = &raw->frag;
5921 perf_output_put(handle, raw->size);
5924 __output_custom(handle, frag->copy,
5925 frag->data, frag->size);
5927 __output_copy(handle, frag->data,
5930 if (perf_raw_frag_last(frag))
5935 __output_skip(handle, NULL, frag->pad);
5941 .size = sizeof(u32),
5944 perf_output_put(handle, raw);
5948 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5949 if (data->br_stack) {
5952 size = data->br_stack->nr
5953 * sizeof(struct perf_branch_entry);
5955 perf_output_put(handle, data->br_stack->nr);
5956 perf_output_copy(handle, data->br_stack->entries, size);
5959 * we always store at least the value of nr
5962 perf_output_put(handle, nr);
5966 if (sample_type & PERF_SAMPLE_REGS_USER) {
5967 u64 abi = data->regs_user.abi;
5970 * If there are no regs to dump, notice it through
5971 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5973 perf_output_put(handle, abi);
5976 u64 mask = event->attr.sample_regs_user;
5977 perf_output_sample_regs(handle,
5978 data->regs_user.regs,
5983 if (sample_type & PERF_SAMPLE_STACK_USER) {
5984 perf_output_sample_ustack(handle,
5985 data->stack_user_size,
5986 data->regs_user.regs);
5989 if (sample_type & PERF_SAMPLE_WEIGHT)
5990 perf_output_put(handle, data->weight);
5992 if (sample_type & PERF_SAMPLE_DATA_SRC)
5993 perf_output_put(handle, data->data_src.val);
5995 if (sample_type & PERF_SAMPLE_TRANSACTION)
5996 perf_output_put(handle, data->txn);
5998 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5999 u64 abi = data->regs_intr.abi;
6001 * If there are no regs to dump, notice it through
6002 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6004 perf_output_put(handle, abi);
6007 u64 mask = event->attr.sample_regs_intr;
6009 perf_output_sample_regs(handle,
6010 data->regs_intr.regs,
6015 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6016 perf_output_put(handle, data->phys_addr);
6018 if (!event->attr.watermark) {
6019 int wakeup_events = event->attr.wakeup_events;
6021 if (wakeup_events) {
6022 struct ring_buffer *rb = handle->rb;
6023 int events = local_inc_return(&rb->events);
6025 if (events >= wakeup_events) {
6026 local_sub(wakeup_events, &rb->events);
6027 local_inc(&rb->wakeup);
6033 static u64 perf_virt_to_phys(u64 virt)
6036 struct page *p = NULL;
6041 if (virt >= TASK_SIZE) {
6042 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6043 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6044 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6045 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6048 * Walking the pages tables for user address.
6049 * Interrupts are disabled, so it prevents any tear down
6050 * of the page tables.
6051 * Try IRQ-safe __get_user_pages_fast first.
6052 * If failed, leave phys_addr as 0.
6054 if ((current->mm != NULL) &&
6055 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6056 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6065 void perf_prepare_sample(struct perf_event_header *header,
6066 struct perf_sample_data *data,
6067 struct perf_event *event,
6068 struct pt_regs *regs)
6070 u64 sample_type = event->attr.sample_type;
6072 header->type = PERF_RECORD_SAMPLE;
6073 header->size = sizeof(*header) + event->header_size;
6076 header->misc |= perf_misc_flags(regs);
6078 __perf_event_header__init_id(header, data, event);
6080 if (sample_type & PERF_SAMPLE_IP)
6081 data->ip = perf_instruction_pointer(regs);
6083 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6086 data->callchain = perf_callchain(event, regs);
6088 if (data->callchain)
6089 size += data->callchain->nr;
6091 header->size += size * sizeof(u64);
6094 if (sample_type & PERF_SAMPLE_RAW) {
6095 struct perf_raw_record *raw = data->raw;
6099 struct perf_raw_frag *frag = &raw->frag;
6104 if (perf_raw_frag_last(frag))
6109 size = round_up(sum + sizeof(u32), sizeof(u64));
6110 raw->size = size - sizeof(u32);
6111 frag->pad = raw->size - sum;
6116 header->size += size;
6119 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6120 int size = sizeof(u64); /* nr */
6121 if (data->br_stack) {
6122 size += data->br_stack->nr
6123 * sizeof(struct perf_branch_entry);
6125 header->size += size;
6128 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6129 perf_sample_regs_user(&data->regs_user, regs,
6130 &data->regs_user_copy);
6132 if (sample_type & PERF_SAMPLE_REGS_USER) {
6133 /* regs dump ABI info */
6134 int size = sizeof(u64);
6136 if (data->regs_user.regs) {
6137 u64 mask = event->attr.sample_regs_user;
6138 size += hweight64(mask) * sizeof(u64);
6141 header->size += size;
6144 if (sample_type & PERF_SAMPLE_STACK_USER) {
6146 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6147 * processed as the last one or have additional check added
6148 * in case new sample type is added, because we could eat
6149 * up the rest of the sample size.
6151 u16 stack_size = event->attr.sample_stack_user;
6152 u16 size = sizeof(u64);
6154 stack_size = perf_sample_ustack_size(stack_size, header->size,
6155 data->regs_user.regs);
6158 * If there is something to dump, add space for the dump
6159 * itself and for the field that tells the dynamic size,
6160 * which is how many have been actually dumped.
6163 size += sizeof(u64) + stack_size;
6165 data->stack_user_size = stack_size;
6166 header->size += size;
6169 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6170 /* regs dump ABI info */
6171 int size = sizeof(u64);
6173 perf_sample_regs_intr(&data->regs_intr, regs);
6175 if (data->regs_intr.regs) {
6176 u64 mask = event->attr.sample_regs_intr;
6178 size += hweight64(mask) * sizeof(u64);
6181 header->size += size;
6184 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6185 data->phys_addr = perf_virt_to_phys(data->addr);
6188 static void __always_inline
6189 __perf_event_output(struct perf_event *event,
6190 struct perf_sample_data *data,
6191 struct pt_regs *regs,
6192 int (*output_begin)(struct perf_output_handle *,
6193 struct perf_event *,
6196 struct perf_output_handle handle;
6197 struct perf_event_header header;
6199 /* protect the callchain buffers */
6202 perf_prepare_sample(&header, data, event, regs);
6204 if (output_begin(&handle, event, header.size))
6207 perf_output_sample(&handle, &header, data, event);
6209 perf_output_end(&handle);
6216 perf_event_output_forward(struct perf_event *event,
6217 struct perf_sample_data *data,
6218 struct pt_regs *regs)
6220 __perf_event_output(event, data, regs, perf_output_begin_forward);
6224 perf_event_output_backward(struct perf_event *event,
6225 struct perf_sample_data *data,
6226 struct pt_regs *regs)
6228 __perf_event_output(event, data, regs, perf_output_begin_backward);
6232 perf_event_output(struct perf_event *event,
6233 struct perf_sample_data *data,
6234 struct pt_regs *regs)
6236 __perf_event_output(event, data, regs, perf_output_begin);
6243 struct perf_read_event {
6244 struct perf_event_header header;
6251 perf_event_read_event(struct perf_event *event,
6252 struct task_struct *task)
6254 struct perf_output_handle handle;
6255 struct perf_sample_data sample;
6256 struct perf_read_event read_event = {
6258 .type = PERF_RECORD_READ,
6260 .size = sizeof(read_event) + event->read_size,
6262 .pid = perf_event_pid(event, task),
6263 .tid = perf_event_tid(event, task),
6267 perf_event_header__init_id(&read_event.header, &sample, event);
6268 ret = perf_output_begin(&handle, event, read_event.header.size);
6272 perf_output_put(&handle, read_event);
6273 perf_output_read(&handle, event);
6274 perf_event__output_id_sample(event, &handle, &sample);
6276 perf_output_end(&handle);
6279 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6282 perf_iterate_ctx(struct perf_event_context *ctx,
6283 perf_iterate_f output,
6284 void *data, bool all)
6286 struct perf_event *event;
6288 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6290 if (event->state < PERF_EVENT_STATE_INACTIVE)
6292 if (!event_filter_match(event))
6296 output(event, data);
6300 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6302 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6303 struct perf_event *event;
6305 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6307 * Skip events that are not fully formed yet; ensure that
6308 * if we observe event->ctx, both event and ctx will be
6309 * complete enough. See perf_install_in_context().
6311 if (!smp_load_acquire(&event->ctx))
6314 if (event->state < PERF_EVENT_STATE_INACTIVE)
6316 if (!event_filter_match(event))
6318 output(event, data);
6323 * Iterate all events that need to receive side-band events.
6325 * For new callers; ensure that account_pmu_sb_event() includes
6326 * your event, otherwise it might not get delivered.
6329 perf_iterate_sb(perf_iterate_f output, void *data,
6330 struct perf_event_context *task_ctx)
6332 struct perf_event_context *ctx;
6339 * If we have task_ctx != NULL we only notify the task context itself.
6340 * The task_ctx is set only for EXIT events before releasing task
6344 perf_iterate_ctx(task_ctx, output, data, false);
6348 perf_iterate_sb_cpu(output, data);
6350 for_each_task_context_nr(ctxn) {
6351 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6353 perf_iterate_ctx(ctx, output, data, false);
6361 * Clear all file-based filters at exec, they'll have to be
6362 * re-instated when/if these objects are mmapped again.
6364 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6366 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6367 struct perf_addr_filter *filter;
6368 unsigned int restart = 0, count = 0;
6369 unsigned long flags;
6371 if (!has_addr_filter(event))
6374 raw_spin_lock_irqsave(&ifh->lock, flags);
6375 list_for_each_entry(filter, &ifh->list, entry) {
6376 if (filter->inode) {
6377 event->addr_filters_offs[count] = 0;
6385 event->addr_filters_gen++;
6386 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6389 perf_event_stop(event, 1);
6392 void perf_event_exec(void)
6394 struct perf_event_context *ctx;
6398 for_each_task_context_nr(ctxn) {
6399 ctx = current->perf_event_ctxp[ctxn];
6403 perf_event_enable_on_exec(ctxn);
6405 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6411 struct remote_output {
6412 struct ring_buffer *rb;
6416 static void __perf_event_output_stop(struct perf_event *event, void *data)
6418 struct perf_event *parent = event->parent;
6419 struct remote_output *ro = data;
6420 struct ring_buffer *rb = ro->rb;
6421 struct stop_event_data sd = {
6425 if (!has_aux(event))
6432 * In case of inheritance, it will be the parent that links to the
6433 * ring-buffer, but it will be the child that's actually using it.
6435 * We are using event::rb to determine if the event should be stopped,
6436 * however this may race with ring_buffer_attach() (through set_output),
6437 * which will make us skip the event that actually needs to be stopped.
6438 * So ring_buffer_attach() has to stop an aux event before re-assigning
6441 if (rcu_dereference(parent->rb) == rb)
6442 ro->err = __perf_event_stop(&sd);
6445 static int __perf_pmu_output_stop(void *info)
6447 struct perf_event *event = info;
6448 struct pmu *pmu = event->pmu;
6449 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6450 struct remote_output ro = {
6455 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6456 if (cpuctx->task_ctx)
6457 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6464 static void perf_pmu_output_stop(struct perf_event *event)
6466 struct perf_event *iter;
6471 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6473 * For per-CPU events, we need to make sure that neither they
6474 * nor their children are running; for cpu==-1 events it's
6475 * sufficient to stop the event itself if it's active, since
6476 * it can't have children.
6480 cpu = READ_ONCE(iter->oncpu);
6485 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6486 if (err == -EAGAIN) {
6495 * task tracking -- fork/exit
6497 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6500 struct perf_task_event {
6501 struct task_struct *task;
6502 struct perf_event_context *task_ctx;
6505 struct perf_event_header header;
6515 static int perf_event_task_match(struct perf_event *event)
6517 return event->attr.comm || event->attr.mmap ||
6518 event->attr.mmap2 || event->attr.mmap_data ||
6522 static void perf_event_task_output(struct perf_event *event,
6525 struct perf_task_event *task_event = data;
6526 struct perf_output_handle handle;
6527 struct perf_sample_data sample;
6528 struct task_struct *task = task_event->task;
6529 int ret, size = task_event->event_id.header.size;
6531 if (!perf_event_task_match(event))
6534 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6536 ret = perf_output_begin(&handle, event,
6537 task_event->event_id.header.size);
6541 task_event->event_id.pid = perf_event_pid(event, task);
6542 task_event->event_id.ppid = perf_event_pid(event, current);
6544 task_event->event_id.tid = perf_event_tid(event, task);
6545 task_event->event_id.ptid = perf_event_tid(event, current);
6547 task_event->event_id.time = perf_event_clock(event);
6549 perf_output_put(&handle, task_event->event_id);
6551 perf_event__output_id_sample(event, &handle, &sample);
6553 perf_output_end(&handle);
6555 task_event->event_id.header.size = size;
6558 static void perf_event_task(struct task_struct *task,
6559 struct perf_event_context *task_ctx,
6562 struct perf_task_event task_event;
6564 if (!atomic_read(&nr_comm_events) &&
6565 !atomic_read(&nr_mmap_events) &&
6566 !atomic_read(&nr_task_events))
6569 task_event = (struct perf_task_event){
6571 .task_ctx = task_ctx,
6574 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6576 .size = sizeof(task_event.event_id),
6586 perf_iterate_sb(perf_event_task_output,
6591 void perf_event_fork(struct task_struct *task)
6593 perf_event_task(task, NULL, 1);
6594 perf_event_namespaces(task);
6601 struct perf_comm_event {
6602 struct task_struct *task;
6607 struct perf_event_header header;
6614 static int perf_event_comm_match(struct perf_event *event)
6616 return event->attr.comm;
6619 static void perf_event_comm_output(struct perf_event *event,
6622 struct perf_comm_event *comm_event = data;
6623 struct perf_output_handle handle;
6624 struct perf_sample_data sample;
6625 int size = comm_event->event_id.header.size;
6628 if (!perf_event_comm_match(event))
6631 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6632 ret = perf_output_begin(&handle, event,
6633 comm_event->event_id.header.size);
6638 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6639 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6641 perf_output_put(&handle, comm_event->event_id);
6642 __output_copy(&handle, comm_event->comm,
6643 comm_event->comm_size);
6645 perf_event__output_id_sample(event, &handle, &sample);
6647 perf_output_end(&handle);
6649 comm_event->event_id.header.size = size;
6652 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6654 char comm[TASK_COMM_LEN];
6657 memset(comm, 0, sizeof(comm));
6658 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6659 size = ALIGN(strlen(comm)+1, sizeof(u64));
6661 comm_event->comm = comm;
6662 comm_event->comm_size = size;
6664 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6666 perf_iterate_sb(perf_event_comm_output,
6671 void perf_event_comm(struct task_struct *task, bool exec)
6673 struct perf_comm_event comm_event;
6675 if (!atomic_read(&nr_comm_events))
6678 comm_event = (struct perf_comm_event){
6684 .type = PERF_RECORD_COMM,
6685 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6693 perf_event_comm_event(&comm_event);
6697 * namespaces tracking
6700 struct perf_namespaces_event {
6701 struct task_struct *task;
6704 struct perf_event_header header;
6709 struct perf_ns_link_info link_info[NR_NAMESPACES];
6713 static int perf_event_namespaces_match(struct perf_event *event)
6715 return event->attr.namespaces;
6718 static void perf_event_namespaces_output(struct perf_event *event,
6721 struct perf_namespaces_event *namespaces_event = data;
6722 struct perf_output_handle handle;
6723 struct perf_sample_data sample;
6724 u16 header_size = namespaces_event->event_id.header.size;
6727 if (!perf_event_namespaces_match(event))
6730 perf_event_header__init_id(&namespaces_event->event_id.header,
6732 ret = perf_output_begin(&handle, event,
6733 namespaces_event->event_id.header.size);
6737 namespaces_event->event_id.pid = perf_event_pid(event,
6738 namespaces_event->task);
6739 namespaces_event->event_id.tid = perf_event_tid(event,
6740 namespaces_event->task);
6742 perf_output_put(&handle, namespaces_event->event_id);
6744 perf_event__output_id_sample(event, &handle, &sample);
6746 perf_output_end(&handle);
6748 namespaces_event->event_id.header.size = header_size;
6751 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6752 struct task_struct *task,
6753 const struct proc_ns_operations *ns_ops)
6755 struct path ns_path;
6756 struct inode *ns_inode;
6759 error = ns_get_path(&ns_path, task, ns_ops);
6761 ns_inode = ns_path.dentry->d_inode;
6762 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6763 ns_link_info->ino = ns_inode->i_ino;
6768 void perf_event_namespaces(struct task_struct *task)
6770 struct perf_namespaces_event namespaces_event;
6771 struct perf_ns_link_info *ns_link_info;
6773 if (!atomic_read(&nr_namespaces_events))
6776 namespaces_event = (struct perf_namespaces_event){
6780 .type = PERF_RECORD_NAMESPACES,
6782 .size = sizeof(namespaces_event.event_id),
6786 .nr_namespaces = NR_NAMESPACES,
6787 /* .link_info[NR_NAMESPACES] */
6791 ns_link_info = namespaces_event.event_id.link_info;
6793 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6794 task, &mntns_operations);
6796 #ifdef CONFIG_USER_NS
6797 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6798 task, &userns_operations);
6800 #ifdef CONFIG_NET_NS
6801 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6802 task, &netns_operations);
6804 #ifdef CONFIG_UTS_NS
6805 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6806 task, &utsns_operations);
6808 #ifdef CONFIG_IPC_NS
6809 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6810 task, &ipcns_operations);
6812 #ifdef CONFIG_PID_NS
6813 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6814 task, &pidns_operations);
6816 #ifdef CONFIG_CGROUPS
6817 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6818 task, &cgroupns_operations);
6821 perf_iterate_sb(perf_event_namespaces_output,
6830 struct perf_mmap_event {
6831 struct vm_area_struct *vma;
6833 const char *file_name;
6841 struct perf_event_header header;
6851 static int perf_event_mmap_match(struct perf_event *event,
6854 struct perf_mmap_event *mmap_event = data;
6855 struct vm_area_struct *vma = mmap_event->vma;
6856 int executable = vma->vm_flags & VM_EXEC;
6858 return (!executable && event->attr.mmap_data) ||
6859 (executable && (event->attr.mmap || event->attr.mmap2));
6862 static void perf_event_mmap_output(struct perf_event *event,
6865 struct perf_mmap_event *mmap_event = data;
6866 struct perf_output_handle handle;
6867 struct perf_sample_data sample;
6868 int size = mmap_event->event_id.header.size;
6871 if (!perf_event_mmap_match(event, data))
6874 if (event->attr.mmap2) {
6875 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6876 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6877 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6878 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6879 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6880 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6881 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6884 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6885 ret = perf_output_begin(&handle, event,
6886 mmap_event->event_id.header.size);
6890 mmap_event->event_id.pid = perf_event_pid(event, current);
6891 mmap_event->event_id.tid = perf_event_tid(event, current);
6893 perf_output_put(&handle, mmap_event->event_id);
6895 if (event->attr.mmap2) {
6896 perf_output_put(&handle, mmap_event->maj);
6897 perf_output_put(&handle, mmap_event->min);
6898 perf_output_put(&handle, mmap_event->ino);
6899 perf_output_put(&handle, mmap_event->ino_generation);
6900 perf_output_put(&handle, mmap_event->prot);
6901 perf_output_put(&handle, mmap_event->flags);
6904 __output_copy(&handle, mmap_event->file_name,
6905 mmap_event->file_size);
6907 perf_event__output_id_sample(event, &handle, &sample);
6909 perf_output_end(&handle);
6911 mmap_event->event_id.header.size = size;
6914 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6916 struct vm_area_struct *vma = mmap_event->vma;
6917 struct file *file = vma->vm_file;
6918 int maj = 0, min = 0;
6919 u64 ino = 0, gen = 0;
6920 u32 prot = 0, flags = 0;
6926 if (vma->vm_flags & VM_READ)
6928 if (vma->vm_flags & VM_WRITE)
6930 if (vma->vm_flags & VM_EXEC)
6933 if (vma->vm_flags & VM_MAYSHARE)
6936 flags = MAP_PRIVATE;
6938 if (vma->vm_flags & VM_DENYWRITE)
6939 flags |= MAP_DENYWRITE;
6940 if (vma->vm_flags & VM_MAYEXEC)
6941 flags |= MAP_EXECUTABLE;
6942 if (vma->vm_flags & VM_LOCKED)
6943 flags |= MAP_LOCKED;
6944 if (vma->vm_flags & VM_HUGETLB)
6945 flags |= MAP_HUGETLB;
6948 struct inode *inode;
6951 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6957 * d_path() works from the end of the rb backwards, so we
6958 * need to add enough zero bytes after the string to handle
6959 * the 64bit alignment we do later.
6961 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6966 inode = file_inode(vma->vm_file);
6967 dev = inode->i_sb->s_dev;
6969 gen = inode->i_generation;
6975 if (vma->vm_ops && vma->vm_ops->name) {
6976 name = (char *) vma->vm_ops->name(vma);
6981 name = (char *)arch_vma_name(vma);
6985 if (vma->vm_start <= vma->vm_mm->start_brk &&
6986 vma->vm_end >= vma->vm_mm->brk) {
6990 if (vma->vm_start <= vma->vm_mm->start_stack &&
6991 vma->vm_end >= vma->vm_mm->start_stack) {
7001 strlcpy(tmp, name, sizeof(tmp));
7005 * Since our buffer works in 8 byte units we need to align our string
7006 * size to a multiple of 8. However, we must guarantee the tail end is
7007 * zero'd out to avoid leaking random bits to userspace.
7009 size = strlen(name)+1;
7010 while (!IS_ALIGNED(size, sizeof(u64)))
7011 name[size++] = '\0';
7013 mmap_event->file_name = name;
7014 mmap_event->file_size = size;
7015 mmap_event->maj = maj;
7016 mmap_event->min = min;
7017 mmap_event->ino = ino;
7018 mmap_event->ino_generation = gen;
7019 mmap_event->prot = prot;
7020 mmap_event->flags = flags;
7022 if (!(vma->vm_flags & VM_EXEC))
7023 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7025 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7027 perf_iterate_sb(perf_event_mmap_output,
7035 * Check whether inode and address range match filter criteria.
7037 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7038 struct file *file, unsigned long offset,
7041 if (filter->inode != file_inode(file))
7044 if (filter->offset > offset + size)
7047 if (filter->offset + filter->size < offset)
7053 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7055 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7056 struct vm_area_struct *vma = data;
7057 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7058 struct file *file = vma->vm_file;
7059 struct perf_addr_filter *filter;
7060 unsigned int restart = 0, count = 0;
7062 if (!has_addr_filter(event))
7068 raw_spin_lock_irqsave(&ifh->lock, flags);
7069 list_for_each_entry(filter, &ifh->list, entry) {
7070 if (perf_addr_filter_match(filter, file, off,
7071 vma->vm_end - vma->vm_start)) {
7072 event->addr_filters_offs[count] = vma->vm_start;
7080 event->addr_filters_gen++;
7081 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7084 perf_event_stop(event, 1);
7088 * Adjust all task's events' filters to the new vma
7090 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7092 struct perf_event_context *ctx;
7096 * Data tracing isn't supported yet and as such there is no need
7097 * to keep track of anything that isn't related to executable code:
7099 if (!(vma->vm_flags & VM_EXEC))
7103 for_each_task_context_nr(ctxn) {
7104 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7108 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7113 void perf_event_mmap(struct vm_area_struct *vma)
7115 struct perf_mmap_event mmap_event;
7117 if (!atomic_read(&nr_mmap_events))
7120 mmap_event = (struct perf_mmap_event){
7126 .type = PERF_RECORD_MMAP,
7127 .misc = PERF_RECORD_MISC_USER,
7132 .start = vma->vm_start,
7133 .len = vma->vm_end - vma->vm_start,
7134 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7136 /* .maj (attr_mmap2 only) */
7137 /* .min (attr_mmap2 only) */
7138 /* .ino (attr_mmap2 only) */
7139 /* .ino_generation (attr_mmap2 only) */
7140 /* .prot (attr_mmap2 only) */
7141 /* .flags (attr_mmap2 only) */
7144 perf_addr_filters_adjust(vma);
7145 perf_event_mmap_event(&mmap_event);
7148 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7149 unsigned long size, u64 flags)
7151 struct perf_output_handle handle;
7152 struct perf_sample_data sample;
7153 struct perf_aux_event {
7154 struct perf_event_header header;
7160 .type = PERF_RECORD_AUX,
7162 .size = sizeof(rec),
7170 perf_event_header__init_id(&rec.header, &sample, event);
7171 ret = perf_output_begin(&handle, event, rec.header.size);
7176 perf_output_put(&handle, rec);
7177 perf_event__output_id_sample(event, &handle, &sample);
7179 perf_output_end(&handle);
7183 * Lost/dropped samples logging
7185 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7187 struct perf_output_handle handle;
7188 struct perf_sample_data sample;
7192 struct perf_event_header header;
7194 } lost_samples_event = {
7196 .type = PERF_RECORD_LOST_SAMPLES,
7198 .size = sizeof(lost_samples_event),
7203 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7205 ret = perf_output_begin(&handle, event,
7206 lost_samples_event.header.size);
7210 perf_output_put(&handle, lost_samples_event);
7211 perf_event__output_id_sample(event, &handle, &sample);
7212 perf_output_end(&handle);
7216 * context_switch tracking
7219 struct perf_switch_event {
7220 struct task_struct *task;
7221 struct task_struct *next_prev;
7224 struct perf_event_header header;
7230 static int perf_event_switch_match(struct perf_event *event)
7232 return event->attr.context_switch;
7235 static void perf_event_switch_output(struct perf_event *event, void *data)
7237 struct perf_switch_event *se = data;
7238 struct perf_output_handle handle;
7239 struct perf_sample_data sample;
7242 if (!perf_event_switch_match(event))
7245 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7246 if (event->ctx->task) {
7247 se->event_id.header.type = PERF_RECORD_SWITCH;
7248 se->event_id.header.size = sizeof(se->event_id.header);
7250 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7251 se->event_id.header.size = sizeof(se->event_id);
7252 se->event_id.next_prev_pid =
7253 perf_event_pid(event, se->next_prev);
7254 se->event_id.next_prev_tid =
7255 perf_event_tid(event, se->next_prev);
7258 perf_event_header__init_id(&se->event_id.header, &sample, event);
7260 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7264 if (event->ctx->task)
7265 perf_output_put(&handle, se->event_id.header);
7267 perf_output_put(&handle, se->event_id);
7269 perf_event__output_id_sample(event, &handle, &sample);
7271 perf_output_end(&handle);
7274 static void perf_event_switch(struct task_struct *task,
7275 struct task_struct *next_prev, bool sched_in)
7277 struct perf_switch_event switch_event;
7279 /* N.B. caller checks nr_switch_events != 0 */
7281 switch_event = (struct perf_switch_event){
7283 .next_prev = next_prev,
7287 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7290 /* .next_prev_pid */
7291 /* .next_prev_tid */
7295 perf_iterate_sb(perf_event_switch_output,
7301 * IRQ throttle logging
7304 static void perf_log_throttle(struct perf_event *event, int enable)
7306 struct perf_output_handle handle;
7307 struct perf_sample_data sample;
7311 struct perf_event_header header;
7315 } throttle_event = {
7317 .type = PERF_RECORD_THROTTLE,
7319 .size = sizeof(throttle_event),
7321 .time = perf_event_clock(event),
7322 .id = primary_event_id(event),
7323 .stream_id = event->id,
7327 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7329 perf_event_header__init_id(&throttle_event.header, &sample, event);
7331 ret = perf_output_begin(&handle, event,
7332 throttle_event.header.size);
7336 perf_output_put(&handle, throttle_event);
7337 perf_event__output_id_sample(event, &handle, &sample);
7338 perf_output_end(&handle);
7341 void perf_event_itrace_started(struct perf_event *event)
7343 event->attach_state |= PERF_ATTACH_ITRACE;
7346 static void perf_log_itrace_start(struct perf_event *event)
7348 struct perf_output_handle handle;
7349 struct perf_sample_data sample;
7350 struct perf_aux_event {
7351 struct perf_event_header header;
7358 event = event->parent;
7360 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7361 event->attach_state & PERF_ATTACH_ITRACE)
7364 rec.header.type = PERF_RECORD_ITRACE_START;
7365 rec.header.misc = 0;
7366 rec.header.size = sizeof(rec);
7367 rec.pid = perf_event_pid(event, current);
7368 rec.tid = perf_event_tid(event, current);
7370 perf_event_header__init_id(&rec.header, &sample, event);
7371 ret = perf_output_begin(&handle, event, rec.header.size);
7376 perf_output_put(&handle, rec);
7377 perf_event__output_id_sample(event, &handle, &sample);
7379 perf_output_end(&handle);
7383 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7385 struct hw_perf_event *hwc = &event->hw;
7389 seq = __this_cpu_read(perf_throttled_seq);
7390 if (seq != hwc->interrupts_seq) {
7391 hwc->interrupts_seq = seq;
7392 hwc->interrupts = 1;
7395 if (unlikely(throttle
7396 && hwc->interrupts >= max_samples_per_tick)) {
7397 __this_cpu_inc(perf_throttled_count);
7398 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7399 hwc->interrupts = MAX_INTERRUPTS;
7400 perf_log_throttle(event, 0);
7405 if (event->attr.freq) {
7406 u64 now = perf_clock();
7407 s64 delta = now - hwc->freq_time_stamp;
7409 hwc->freq_time_stamp = now;
7411 if (delta > 0 && delta < 2*TICK_NSEC)
7412 perf_adjust_period(event, delta, hwc->last_period, true);
7418 int perf_event_account_interrupt(struct perf_event *event)
7420 return __perf_event_account_interrupt(event, 1);
7424 * Generic event overflow handling, sampling.
7427 static int __perf_event_overflow(struct perf_event *event,
7428 int throttle, struct perf_sample_data *data,
7429 struct pt_regs *regs)
7431 int events = atomic_read(&event->event_limit);
7435 * Non-sampling counters might still use the PMI to fold short
7436 * hardware counters, ignore those.
7438 if (unlikely(!is_sampling_event(event)))
7441 ret = __perf_event_account_interrupt(event, throttle);
7444 * XXX event_limit might not quite work as expected on inherited
7448 event->pending_kill = POLL_IN;
7449 if (events && atomic_dec_and_test(&event->event_limit)) {
7451 event->pending_kill = POLL_HUP;
7453 perf_event_disable_inatomic(event);
7456 READ_ONCE(event->overflow_handler)(event, data, regs);
7458 if (*perf_event_fasync(event) && event->pending_kill) {
7459 event->pending_wakeup = 1;
7460 irq_work_queue(&event->pending);
7466 int perf_event_overflow(struct perf_event *event,
7467 struct perf_sample_data *data,
7468 struct pt_regs *regs)
7470 return __perf_event_overflow(event, 1, data, regs);
7474 * Generic software event infrastructure
7477 struct swevent_htable {
7478 struct swevent_hlist *swevent_hlist;
7479 struct mutex hlist_mutex;
7482 /* Recursion avoidance in each contexts */
7483 int recursion[PERF_NR_CONTEXTS];
7486 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7489 * We directly increment event->count and keep a second value in
7490 * event->hw.period_left to count intervals. This period event
7491 * is kept in the range [-sample_period, 0] so that we can use the
7495 u64 perf_swevent_set_period(struct perf_event *event)
7497 struct hw_perf_event *hwc = &event->hw;
7498 u64 period = hwc->last_period;
7502 hwc->last_period = hwc->sample_period;
7505 old = val = local64_read(&hwc->period_left);
7509 nr = div64_u64(period + val, period);
7510 offset = nr * period;
7512 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7518 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7519 struct perf_sample_data *data,
7520 struct pt_regs *regs)
7522 struct hw_perf_event *hwc = &event->hw;
7526 overflow = perf_swevent_set_period(event);
7528 if (hwc->interrupts == MAX_INTERRUPTS)
7531 for (; overflow; overflow--) {
7532 if (__perf_event_overflow(event, throttle,
7535 * We inhibit the overflow from happening when
7536 * hwc->interrupts == MAX_INTERRUPTS.
7544 static void perf_swevent_event(struct perf_event *event, u64 nr,
7545 struct perf_sample_data *data,
7546 struct pt_regs *regs)
7548 struct hw_perf_event *hwc = &event->hw;
7550 local64_add(nr, &event->count);
7555 if (!is_sampling_event(event))
7558 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7560 return perf_swevent_overflow(event, 1, data, regs);
7562 data->period = event->hw.last_period;
7564 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7565 return perf_swevent_overflow(event, 1, data, regs);
7567 if (local64_add_negative(nr, &hwc->period_left))
7570 perf_swevent_overflow(event, 0, data, regs);
7573 static int perf_exclude_event(struct perf_event *event,
7574 struct pt_regs *regs)
7576 if (event->hw.state & PERF_HES_STOPPED)
7580 if (event->attr.exclude_user && user_mode(regs))
7583 if (event->attr.exclude_kernel && !user_mode(regs))
7590 static int perf_swevent_match(struct perf_event *event,
7591 enum perf_type_id type,
7593 struct perf_sample_data *data,
7594 struct pt_regs *regs)
7596 if (event->attr.type != type)
7599 if (event->attr.config != event_id)
7602 if (perf_exclude_event(event, regs))
7608 static inline u64 swevent_hash(u64 type, u32 event_id)
7610 u64 val = event_id | (type << 32);
7612 return hash_64(val, SWEVENT_HLIST_BITS);
7615 static inline struct hlist_head *
7616 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7618 u64 hash = swevent_hash(type, event_id);
7620 return &hlist->heads[hash];
7623 /* For the read side: events when they trigger */
7624 static inline struct hlist_head *
7625 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7627 struct swevent_hlist *hlist;
7629 hlist = rcu_dereference(swhash->swevent_hlist);
7633 return __find_swevent_head(hlist, type, event_id);
7636 /* For the event head insertion and removal in the hlist */
7637 static inline struct hlist_head *
7638 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7640 struct swevent_hlist *hlist;
7641 u32 event_id = event->attr.config;
7642 u64 type = event->attr.type;
7645 * Event scheduling is always serialized against hlist allocation
7646 * and release. Which makes the protected version suitable here.
7647 * The context lock guarantees that.
7649 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7650 lockdep_is_held(&event->ctx->lock));
7654 return __find_swevent_head(hlist, type, event_id);
7657 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7659 struct perf_sample_data *data,
7660 struct pt_regs *regs)
7662 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7663 struct perf_event *event;
7664 struct hlist_head *head;
7667 head = find_swevent_head_rcu(swhash, type, event_id);
7671 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7672 if (perf_swevent_match(event, type, event_id, data, regs))
7673 perf_swevent_event(event, nr, data, regs);
7679 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7681 int perf_swevent_get_recursion_context(void)
7683 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7685 return get_recursion_context(swhash->recursion);
7687 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7689 void perf_swevent_put_recursion_context(int rctx)
7691 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7693 put_recursion_context(swhash->recursion, rctx);
7696 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7698 struct perf_sample_data data;
7700 if (WARN_ON_ONCE(!regs))
7703 perf_sample_data_init(&data, addr, 0);
7704 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7707 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7711 preempt_disable_notrace();
7712 rctx = perf_swevent_get_recursion_context();
7713 if (unlikely(rctx < 0))
7716 ___perf_sw_event(event_id, nr, regs, addr);
7718 perf_swevent_put_recursion_context(rctx);
7720 preempt_enable_notrace();
7723 static void perf_swevent_read(struct perf_event *event)
7727 static int perf_swevent_add(struct perf_event *event, int flags)
7729 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7730 struct hw_perf_event *hwc = &event->hw;
7731 struct hlist_head *head;
7733 if (is_sampling_event(event)) {
7734 hwc->last_period = hwc->sample_period;
7735 perf_swevent_set_period(event);
7738 hwc->state = !(flags & PERF_EF_START);
7740 head = find_swevent_head(swhash, event);
7741 if (WARN_ON_ONCE(!head))
7744 hlist_add_head_rcu(&event->hlist_entry, head);
7745 perf_event_update_userpage(event);
7750 static void perf_swevent_del(struct perf_event *event, int flags)
7752 hlist_del_rcu(&event->hlist_entry);
7755 static void perf_swevent_start(struct perf_event *event, int flags)
7757 event->hw.state = 0;
7760 static void perf_swevent_stop(struct perf_event *event, int flags)
7762 event->hw.state = PERF_HES_STOPPED;
7765 /* Deref the hlist from the update side */
7766 static inline struct swevent_hlist *
7767 swevent_hlist_deref(struct swevent_htable *swhash)
7769 return rcu_dereference_protected(swhash->swevent_hlist,
7770 lockdep_is_held(&swhash->hlist_mutex));
7773 static void swevent_hlist_release(struct swevent_htable *swhash)
7775 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7780 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7781 kfree_rcu(hlist, rcu_head);
7784 static void swevent_hlist_put_cpu(int cpu)
7786 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7788 mutex_lock(&swhash->hlist_mutex);
7790 if (!--swhash->hlist_refcount)
7791 swevent_hlist_release(swhash);
7793 mutex_unlock(&swhash->hlist_mutex);
7796 static void swevent_hlist_put(void)
7800 for_each_possible_cpu(cpu)
7801 swevent_hlist_put_cpu(cpu);
7804 static int swevent_hlist_get_cpu(int cpu)
7806 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7809 mutex_lock(&swhash->hlist_mutex);
7810 if (!swevent_hlist_deref(swhash) &&
7811 cpumask_test_cpu(cpu, perf_online_mask)) {
7812 struct swevent_hlist *hlist;
7814 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7819 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7821 swhash->hlist_refcount++;
7823 mutex_unlock(&swhash->hlist_mutex);
7828 static int swevent_hlist_get(void)
7830 int err, cpu, failed_cpu;
7832 mutex_lock(&pmus_lock);
7833 for_each_possible_cpu(cpu) {
7834 err = swevent_hlist_get_cpu(cpu);
7840 mutex_unlock(&pmus_lock);
7843 for_each_possible_cpu(cpu) {
7844 if (cpu == failed_cpu)
7846 swevent_hlist_put_cpu(cpu);
7848 mutex_unlock(&pmus_lock);
7852 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7854 static void sw_perf_event_destroy(struct perf_event *event)
7856 u64 event_id = event->attr.config;
7858 WARN_ON(event->parent);
7860 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7861 swevent_hlist_put();
7864 static int perf_swevent_init(struct perf_event *event)
7866 u64 event_id = event->attr.config;
7868 if (event->attr.type != PERF_TYPE_SOFTWARE)
7872 * no branch sampling for software events
7874 if (has_branch_stack(event))
7878 case PERF_COUNT_SW_CPU_CLOCK:
7879 case PERF_COUNT_SW_TASK_CLOCK:
7886 if (event_id >= PERF_COUNT_SW_MAX)
7889 if (!event->parent) {
7892 err = swevent_hlist_get();
7896 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7897 event->destroy = sw_perf_event_destroy;
7903 static struct pmu perf_swevent = {
7904 .task_ctx_nr = perf_sw_context,
7906 .capabilities = PERF_PMU_CAP_NO_NMI,
7908 .event_init = perf_swevent_init,
7909 .add = perf_swevent_add,
7910 .del = perf_swevent_del,
7911 .start = perf_swevent_start,
7912 .stop = perf_swevent_stop,
7913 .read = perf_swevent_read,
7916 #ifdef CONFIG_EVENT_TRACING
7918 static int perf_tp_filter_match(struct perf_event *event,
7919 struct perf_sample_data *data)
7921 void *record = data->raw->frag.data;
7923 /* only top level events have filters set */
7925 event = event->parent;
7927 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7932 static int perf_tp_event_match(struct perf_event *event,
7933 struct perf_sample_data *data,
7934 struct pt_regs *regs)
7936 if (event->hw.state & PERF_HES_STOPPED)
7939 * All tracepoints are from kernel-space.
7941 if (event->attr.exclude_kernel)
7944 if (!perf_tp_filter_match(event, data))
7950 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7951 struct trace_event_call *call, u64 count,
7952 struct pt_regs *regs, struct hlist_head *head,
7953 struct task_struct *task)
7955 struct bpf_prog *prog = call->prog;
7958 *(struct pt_regs **)raw_data = regs;
7959 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7960 perf_swevent_put_recursion_context(rctx);
7964 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7967 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7969 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7970 struct pt_regs *regs, struct hlist_head *head, int rctx,
7971 struct task_struct *task, struct perf_event *event)
7973 struct perf_sample_data data;
7975 struct perf_raw_record raw = {
7982 perf_sample_data_init(&data, 0, 0);
7985 perf_trace_buf_update(record, event_type);
7987 /* Use the given event instead of the hlist */
7989 if (perf_tp_event_match(event, &data, regs))
7990 perf_swevent_event(event, count, &data, regs);
7992 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7993 if (perf_tp_event_match(event, &data, regs))
7994 perf_swevent_event(event, count, &data, regs);
7999 * If we got specified a target task, also iterate its context and
8000 * deliver this event there too.
8002 if (task && task != current) {
8003 struct perf_event_context *ctx;
8004 struct trace_entry *entry = record;
8007 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8011 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8012 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8014 if (event->attr.config != entry->type)
8016 if (perf_tp_event_match(event, &data, regs))
8017 perf_swevent_event(event, count, &data, regs);
8023 perf_swevent_put_recursion_context(rctx);
8025 EXPORT_SYMBOL_GPL(perf_tp_event);
8027 static void tp_perf_event_destroy(struct perf_event *event)
8029 perf_trace_destroy(event);
8032 static int perf_tp_event_init(struct perf_event *event)
8036 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8040 * no branch sampling for tracepoint events
8042 if (has_branch_stack(event))
8045 err = perf_trace_init(event);
8049 event->destroy = tp_perf_event_destroy;
8054 static struct pmu perf_tracepoint = {
8055 .task_ctx_nr = perf_sw_context,
8057 .event_init = perf_tp_event_init,
8058 .add = perf_trace_add,
8059 .del = perf_trace_del,
8060 .start = perf_swevent_start,
8061 .stop = perf_swevent_stop,
8062 .read = perf_swevent_read,
8065 static inline void perf_tp_register(void)
8067 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8070 static void perf_event_free_filter(struct perf_event *event)
8072 ftrace_profile_free_filter(event);
8075 #ifdef CONFIG_BPF_SYSCALL
8076 static void bpf_overflow_handler(struct perf_event *event,
8077 struct perf_sample_data *data,
8078 struct pt_regs *regs)
8080 struct bpf_perf_event_data_kern ctx = {
8087 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8090 ret = BPF_PROG_RUN(event->prog, &ctx);
8093 __this_cpu_dec(bpf_prog_active);
8098 event->orig_overflow_handler(event, data, regs);
8101 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8103 struct bpf_prog *prog;
8105 if (event->overflow_handler_context)
8106 /* hw breakpoint or kernel counter */
8112 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8114 return PTR_ERR(prog);
8117 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8118 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8122 static void perf_event_free_bpf_handler(struct perf_event *event)
8124 struct bpf_prog *prog = event->prog;
8129 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8134 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8138 static void perf_event_free_bpf_handler(struct perf_event *event)
8143 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8145 bool is_kprobe, is_tracepoint, is_syscall_tp;
8146 struct bpf_prog *prog;
8148 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8149 return perf_event_set_bpf_handler(event, prog_fd);
8151 if (event->tp_event->prog)
8154 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8155 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8156 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8157 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8158 /* bpf programs can only be attached to u/kprobe or tracepoint */
8161 prog = bpf_prog_get(prog_fd);
8163 return PTR_ERR(prog);
8165 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8166 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8167 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8168 /* valid fd, but invalid bpf program type */
8173 if (is_tracepoint || is_syscall_tp) {
8174 int off = trace_event_get_offsets(event->tp_event);
8176 if (prog->aux->max_ctx_offset > off) {
8181 event->tp_event->prog = prog;
8182 event->tp_event->bpf_prog_owner = event;
8187 static void perf_event_free_bpf_prog(struct perf_event *event)
8189 struct bpf_prog *prog;
8191 perf_event_free_bpf_handler(event);
8193 if (!event->tp_event)
8196 prog = event->tp_event->prog;
8197 if (prog && event->tp_event->bpf_prog_owner == event) {
8198 event->tp_event->prog = NULL;
8205 static inline void perf_tp_register(void)
8209 static void perf_event_free_filter(struct perf_event *event)
8213 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8218 static void perf_event_free_bpf_prog(struct perf_event *event)
8221 #endif /* CONFIG_EVENT_TRACING */
8223 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8224 void perf_bp_event(struct perf_event *bp, void *data)
8226 struct perf_sample_data sample;
8227 struct pt_regs *regs = data;
8229 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8231 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8232 perf_swevent_event(bp, 1, &sample, regs);
8237 * Allocate a new address filter
8239 static struct perf_addr_filter *
8240 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8242 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8243 struct perf_addr_filter *filter;
8245 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8249 INIT_LIST_HEAD(&filter->entry);
8250 list_add_tail(&filter->entry, filters);
8255 static void free_filters_list(struct list_head *filters)
8257 struct perf_addr_filter *filter, *iter;
8259 list_for_each_entry_safe(filter, iter, filters, entry) {
8261 iput(filter->inode);
8262 list_del(&filter->entry);
8268 * Free existing address filters and optionally install new ones
8270 static void perf_addr_filters_splice(struct perf_event *event,
8271 struct list_head *head)
8273 unsigned long flags;
8276 if (!has_addr_filter(event))
8279 /* don't bother with children, they don't have their own filters */
8283 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8285 list_splice_init(&event->addr_filters.list, &list);
8287 list_splice(head, &event->addr_filters.list);
8289 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8291 free_filters_list(&list);
8295 * Scan through mm's vmas and see if one of them matches the
8296 * @filter; if so, adjust filter's address range.
8297 * Called with mm::mmap_sem down for reading.
8299 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8300 struct mm_struct *mm)
8302 struct vm_area_struct *vma;
8304 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8305 struct file *file = vma->vm_file;
8306 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8307 unsigned long vma_size = vma->vm_end - vma->vm_start;
8312 if (!perf_addr_filter_match(filter, file, off, vma_size))
8315 return vma->vm_start;
8322 * Update event's address range filters based on the
8323 * task's existing mappings, if any.
8325 static void perf_event_addr_filters_apply(struct perf_event *event)
8327 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8328 struct task_struct *task = READ_ONCE(event->ctx->task);
8329 struct perf_addr_filter *filter;
8330 struct mm_struct *mm = NULL;
8331 unsigned int count = 0;
8332 unsigned long flags;
8335 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8336 * will stop on the parent's child_mutex that our caller is also holding
8338 if (task == TASK_TOMBSTONE)
8341 if (!ifh->nr_file_filters)
8344 mm = get_task_mm(event->ctx->task);
8348 down_read(&mm->mmap_sem);
8350 raw_spin_lock_irqsave(&ifh->lock, flags);
8351 list_for_each_entry(filter, &ifh->list, entry) {
8352 event->addr_filters_offs[count] = 0;
8355 * Adjust base offset if the filter is associated to a binary
8356 * that needs to be mapped:
8359 event->addr_filters_offs[count] =
8360 perf_addr_filter_apply(filter, mm);
8365 event->addr_filters_gen++;
8366 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8368 up_read(&mm->mmap_sem);
8373 perf_event_stop(event, 1);
8377 * Address range filtering: limiting the data to certain
8378 * instruction address ranges. Filters are ioctl()ed to us from
8379 * userspace as ascii strings.
8381 * Filter string format:
8384 * where ACTION is one of the
8385 * * "filter": limit the trace to this region
8386 * * "start": start tracing from this address
8387 * * "stop": stop tracing at this address/region;
8389 * * for kernel addresses: <start address>[/<size>]
8390 * * for object files: <start address>[/<size>]@</path/to/object/file>
8392 * if <size> is not specified, the range is treated as a single address.
8406 IF_STATE_ACTION = 0,
8411 static const match_table_t if_tokens = {
8412 { IF_ACT_FILTER, "filter" },
8413 { IF_ACT_START, "start" },
8414 { IF_ACT_STOP, "stop" },
8415 { IF_SRC_FILE, "%u/%u@%s" },
8416 { IF_SRC_KERNEL, "%u/%u" },
8417 { IF_SRC_FILEADDR, "%u@%s" },
8418 { IF_SRC_KERNELADDR, "%u" },
8419 { IF_ACT_NONE, NULL },
8423 * Address filter string parser
8426 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8427 struct list_head *filters)
8429 struct perf_addr_filter *filter = NULL;
8430 char *start, *orig, *filename = NULL;
8432 substring_t args[MAX_OPT_ARGS];
8433 int state = IF_STATE_ACTION, token;
8434 unsigned int kernel = 0;
8437 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8441 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8447 /* filter definition begins */
8448 if (state == IF_STATE_ACTION) {
8449 filter = perf_addr_filter_new(event, filters);
8454 token = match_token(start, if_tokens, args);
8461 if (state != IF_STATE_ACTION)
8464 state = IF_STATE_SOURCE;
8467 case IF_SRC_KERNELADDR:
8471 case IF_SRC_FILEADDR:
8473 if (state != IF_STATE_SOURCE)
8476 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8480 ret = kstrtoul(args[0].from, 0, &filter->offset);
8484 if (filter->range) {
8486 ret = kstrtoul(args[1].from, 0, &filter->size);
8491 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8492 int fpos = filter->range ? 2 : 1;
8494 filename = match_strdup(&args[fpos]);
8501 state = IF_STATE_END;
8509 * Filter definition is fully parsed, validate and install it.
8510 * Make sure that it doesn't contradict itself or the event's
8513 if (state == IF_STATE_END) {
8515 if (kernel && event->attr.exclude_kernel)
8523 * For now, we only support file-based filters
8524 * in per-task events; doing so for CPU-wide
8525 * events requires additional context switching
8526 * trickery, since same object code will be
8527 * mapped at different virtual addresses in
8528 * different processes.
8531 if (!event->ctx->task)
8532 goto fail_free_name;
8534 /* look up the path and grab its inode */
8535 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8537 goto fail_free_name;
8539 filter->inode = igrab(d_inode(path.dentry));
8545 if (!filter->inode ||
8546 !S_ISREG(filter->inode->i_mode))
8547 /* free_filters_list() will iput() */
8550 event->addr_filters.nr_file_filters++;
8553 /* ready to consume more filters */
8554 state = IF_STATE_ACTION;
8559 if (state != IF_STATE_ACTION)
8569 free_filters_list(filters);
8576 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8582 * Since this is called in perf_ioctl() path, we're already holding
8585 lockdep_assert_held(&event->ctx->mutex);
8587 if (WARN_ON_ONCE(event->parent))
8590 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8592 goto fail_clear_files;
8594 ret = event->pmu->addr_filters_validate(&filters);
8596 goto fail_free_filters;
8598 /* remove existing filters, if any */
8599 perf_addr_filters_splice(event, &filters);
8601 /* install new filters */
8602 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8607 free_filters_list(&filters);
8610 event->addr_filters.nr_file_filters = 0;
8615 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8620 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8621 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8622 !has_addr_filter(event))
8625 filter_str = strndup_user(arg, PAGE_SIZE);
8626 if (IS_ERR(filter_str))
8627 return PTR_ERR(filter_str);
8629 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8630 event->attr.type == PERF_TYPE_TRACEPOINT)
8631 ret = ftrace_profile_set_filter(event, event->attr.config,
8633 else if (has_addr_filter(event))
8634 ret = perf_event_set_addr_filter(event, filter_str);
8641 * hrtimer based swevent callback
8644 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8646 enum hrtimer_restart ret = HRTIMER_RESTART;
8647 struct perf_sample_data data;
8648 struct pt_regs *regs;
8649 struct perf_event *event;
8652 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8654 if (event->state != PERF_EVENT_STATE_ACTIVE)
8655 return HRTIMER_NORESTART;
8657 event->pmu->read(event);
8659 perf_sample_data_init(&data, 0, event->hw.last_period);
8660 regs = get_irq_regs();
8662 if (regs && !perf_exclude_event(event, regs)) {
8663 if (!(event->attr.exclude_idle && is_idle_task(current)))
8664 if (__perf_event_overflow(event, 1, &data, regs))
8665 ret = HRTIMER_NORESTART;
8668 period = max_t(u64, 10000, event->hw.sample_period);
8669 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8674 static void perf_swevent_start_hrtimer(struct perf_event *event)
8676 struct hw_perf_event *hwc = &event->hw;
8679 if (!is_sampling_event(event))
8682 period = local64_read(&hwc->period_left);
8687 local64_set(&hwc->period_left, 0);
8689 period = max_t(u64, 10000, hwc->sample_period);
8691 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8692 HRTIMER_MODE_REL_PINNED);
8695 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8697 struct hw_perf_event *hwc = &event->hw;
8699 if (is_sampling_event(event)) {
8700 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8701 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8703 hrtimer_cancel(&hwc->hrtimer);
8707 static void perf_swevent_init_hrtimer(struct perf_event *event)
8709 struct hw_perf_event *hwc = &event->hw;
8711 if (!is_sampling_event(event))
8714 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8715 hwc->hrtimer.function = perf_swevent_hrtimer;
8718 * Since hrtimers have a fixed rate, we can do a static freq->period
8719 * mapping and avoid the whole period adjust feedback stuff.
8721 if (event->attr.freq) {
8722 long freq = event->attr.sample_freq;
8724 event->attr.sample_period = NSEC_PER_SEC / freq;
8725 hwc->sample_period = event->attr.sample_period;
8726 local64_set(&hwc->period_left, hwc->sample_period);
8727 hwc->last_period = hwc->sample_period;
8728 event->attr.freq = 0;
8733 * Software event: cpu wall time clock
8736 static void cpu_clock_event_update(struct perf_event *event)
8741 now = local_clock();
8742 prev = local64_xchg(&event->hw.prev_count, now);
8743 local64_add(now - prev, &event->count);
8746 static void cpu_clock_event_start(struct perf_event *event, int flags)
8748 local64_set(&event->hw.prev_count, local_clock());
8749 perf_swevent_start_hrtimer(event);
8752 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8754 perf_swevent_cancel_hrtimer(event);
8755 cpu_clock_event_update(event);
8758 static int cpu_clock_event_add(struct perf_event *event, int flags)
8760 if (flags & PERF_EF_START)
8761 cpu_clock_event_start(event, flags);
8762 perf_event_update_userpage(event);
8767 static void cpu_clock_event_del(struct perf_event *event, int flags)
8769 cpu_clock_event_stop(event, flags);
8772 static void cpu_clock_event_read(struct perf_event *event)
8774 cpu_clock_event_update(event);
8777 static int cpu_clock_event_init(struct perf_event *event)
8779 if (event->attr.type != PERF_TYPE_SOFTWARE)
8782 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8786 * no branch sampling for software events
8788 if (has_branch_stack(event))
8791 perf_swevent_init_hrtimer(event);
8796 static struct pmu perf_cpu_clock = {
8797 .task_ctx_nr = perf_sw_context,
8799 .capabilities = PERF_PMU_CAP_NO_NMI,
8801 .event_init = cpu_clock_event_init,
8802 .add = cpu_clock_event_add,
8803 .del = cpu_clock_event_del,
8804 .start = cpu_clock_event_start,
8805 .stop = cpu_clock_event_stop,
8806 .read = cpu_clock_event_read,
8810 * Software event: task time clock
8813 static void task_clock_event_update(struct perf_event *event, u64 now)
8818 prev = local64_xchg(&event->hw.prev_count, now);
8820 local64_add(delta, &event->count);
8823 static void task_clock_event_start(struct perf_event *event, int flags)
8825 local64_set(&event->hw.prev_count, event->ctx->time);
8826 perf_swevent_start_hrtimer(event);
8829 static void task_clock_event_stop(struct perf_event *event, int flags)
8831 perf_swevent_cancel_hrtimer(event);
8832 task_clock_event_update(event, event->ctx->time);
8835 static int task_clock_event_add(struct perf_event *event, int flags)
8837 if (flags & PERF_EF_START)
8838 task_clock_event_start(event, flags);
8839 perf_event_update_userpage(event);
8844 static void task_clock_event_del(struct perf_event *event, int flags)
8846 task_clock_event_stop(event, PERF_EF_UPDATE);
8849 static void task_clock_event_read(struct perf_event *event)
8851 u64 now = perf_clock();
8852 u64 delta = now - event->ctx->timestamp;
8853 u64 time = event->ctx->time + delta;
8855 task_clock_event_update(event, time);
8858 static int task_clock_event_init(struct perf_event *event)
8860 if (event->attr.type != PERF_TYPE_SOFTWARE)
8863 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8867 * no branch sampling for software events
8869 if (has_branch_stack(event))
8872 perf_swevent_init_hrtimer(event);
8877 static struct pmu perf_task_clock = {
8878 .task_ctx_nr = perf_sw_context,
8880 .capabilities = PERF_PMU_CAP_NO_NMI,
8882 .event_init = task_clock_event_init,
8883 .add = task_clock_event_add,
8884 .del = task_clock_event_del,
8885 .start = task_clock_event_start,
8886 .stop = task_clock_event_stop,
8887 .read = task_clock_event_read,
8890 static void perf_pmu_nop_void(struct pmu *pmu)
8894 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8898 static int perf_pmu_nop_int(struct pmu *pmu)
8903 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8905 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8907 __this_cpu_write(nop_txn_flags, flags);
8909 if (flags & ~PERF_PMU_TXN_ADD)
8912 perf_pmu_disable(pmu);
8915 static int perf_pmu_commit_txn(struct pmu *pmu)
8917 unsigned int flags = __this_cpu_read(nop_txn_flags);
8919 __this_cpu_write(nop_txn_flags, 0);
8921 if (flags & ~PERF_PMU_TXN_ADD)
8924 perf_pmu_enable(pmu);
8928 static void perf_pmu_cancel_txn(struct pmu *pmu)
8930 unsigned int flags = __this_cpu_read(nop_txn_flags);
8932 __this_cpu_write(nop_txn_flags, 0);
8934 if (flags & ~PERF_PMU_TXN_ADD)
8937 perf_pmu_enable(pmu);
8940 static int perf_event_idx_default(struct perf_event *event)
8946 * Ensures all contexts with the same task_ctx_nr have the same
8947 * pmu_cpu_context too.
8949 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8956 list_for_each_entry(pmu, &pmus, entry) {
8957 if (pmu->task_ctx_nr == ctxn)
8958 return pmu->pmu_cpu_context;
8964 static void free_pmu_context(struct pmu *pmu)
8967 * Static contexts such as perf_sw_context have a global lifetime
8968 * and may be shared between different PMUs. Avoid freeing them
8969 * when a single PMU is going away.
8971 if (pmu->task_ctx_nr > perf_invalid_context)
8974 mutex_lock(&pmus_lock);
8975 free_percpu(pmu->pmu_cpu_context);
8976 mutex_unlock(&pmus_lock);
8980 * Let userspace know that this PMU supports address range filtering:
8982 static ssize_t nr_addr_filters_show(struct device *dev,
8983 struct device_attribute *attr,
8986 struct pmu *pmu = dev_get_drvdata(dev);
8988 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8990 DEVICE_ATTR_RO(nr_addr_filters);
8992 static struct idr pmu_idr;
8995 type_show(struct device *dev, struct device_attribute *attr, char *page)
8997 struct pmu *pmu = dev_get_drvdata(dev);
8999 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9001 static DEVICE_ATTR_RO(type);
9004 perf_event_mux_interval_ms_show(struct device *dev,
9005 struct device_attribute *attr,
9008 struct pmu *pmu = dev_get_drvdata(dev);
9010 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9013 static DEFINE_MUTEX(mux_interval_mutex);
9016 perf_event_mux_interval_ms_store(struct device *dev,
9017 struct device_attribute *attr,
9018 const char *buf, size_t count)
9020 struct pmu *pmu = dev_get_drvdata(dev);
9021 int timer, cpu, ret;
9023 ret = kstrtoint(buf, 0, &timer);
9030 /* same value, noting to do */
9031 if (timer == pmu->hrtimer_interval_ms)
9034 mutex_lock(&mux_interval_mutex);
9035 pmu->hrtimer_interval_ms = timer;
9037 /* update all cpuctx for this PMU */
9039 for_each_online_cpu(cpu) {
9040 struct perf_cpu_context *cpuctx;
9041 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9042 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9044 cpu_function_call(cpu,
9045 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9048 mutex_unlock(&mux_interval_mutex);
9052 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9054 static struct attribute *pmu_dev_attrs[] = {
9055 &dev_attr_type.attr,
9056 &dev_attr_perf_event_mux_interval_ms.attr,
9059 ATTRIBUTE_GROUPS(pmu_dev);
9061 static int pmu_bus_running;
9062 static struct bus_type pmu_bus = {
9063 .name = "event_source",
9064 .dev_groups = pmu_dev_groups,
9067 static void pmu_dev_release(struct device *dev)
9072 static int pmu_dev_alloc(struct pmu *pmu)
9076 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9080 pmu->dev->groups = pmu->attr_groups;
9081 device_initialize(pmu->dev);
9082 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9086 dev_set_drvdata(pmu->dev, pmu);
9087 pmu->dev->bus = &pmu_bus;
9088 pmu->dev->release = pmu_dev_release;
9089 ret = device_add(pmu->dev);
9093 /* For PMUs with address filters, throw in an extra attribute: */
9094 if (pmu->nr_addr_filters)
9095 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9104 device_del(pmu->dev);
9107 put_device(pmu->dev);
9111 static struct lock_class_key cpuctx_mutex;
9112 static struct lock_class_key cpuctx_lock;
9114 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9118 mutex_lock(&pmus_lock);
9120 pmu->pmu_disable_count = alloc_percpu(int);
9121 if (!pmu->pmu_disable_count)
9130 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9138 if (pmu_bus_running) {
9139 ret = pmu_dev_alloc(pmu);
9145 if (pmu->task_ctx_nr == perf_hw_context) {
9146 static int hw_context_taken = 0;
9149 * Other than systems with heterogeneous CPUs, it never makes
9150 * sense for two PMUs to share perf_hw_context. PMUs which are
9151 * uncore must use perf_invalid_context.
9153 if (WARN_ON_ONCE(hw_context_taken &&
9154 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9155 pmu->task_ctx_nr = perf_invalid_context;
9157 hw_context_taken = 1;
9160 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9161 if (pmu->pmu_cpu_context)
9162 goto got_cpu_context;
9165 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9166 if (!pmu->pmu_cpu_context)
9169 for_each_possible_cpu(cpu) {
9170 struct perf_cpu_context *cpuctx;
9172 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9173 __perf_event_init_context(&cpuctx->ctx);
9174 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9175 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9176 cpuctx->ctx.pmu = pmu;
9177 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9179 __perf_mux_hrtimer_init(cpuctx, cpu);
9183 if (!pmu->start_txn) {
9184 if (pmu->pmu_enable) {
9186 * If we have pmu_enable/pmu_disable calls, install
9187 * transaction stubs that use that to try and batch
9188 * hardware accesses.
9190 pmu->start_txn = perf_pmu_start_txn;
9191 pmu->commit_txn = perf_pmu_commit_txn;
9192 pmu->cancel_txn = perf_pmu_cancel_txn;
9194 pmu->start_txn = perf_pmu_nop_txn;
9195 pmu->commit_txn = perf_pmu_nop_int;
9196 pmu->cancel_txn = perf_pmu_nop_void;
9200 if (!pmu->pmu_enable) {
9201 pmu->pmu_enable = perf_pmu_nop_void;
9202 pmu->pmu_disable = perf_pmu_nop_void;
9205 if (!pmu->event_idx)
9206 pmu->event_idx = perf_event_idx_default;
9208 list_add_rcu(&pmu->entry, &pmus);
9209 atomic_set(&pmu->exclusive_cnt, 0);
9212 mutex_unlock(&pmus_lock);
9217 device_del(pmu->dev);
9218 put_device(pmu->dev);
9221 if (pmu->type >= PERF_TYPE_MAX)
9222 idr_remove(&pmu_idr, pmu->type);
9225 free_percpu(pmu->pmu_disable_count);
9228 EXPORT_SYMBOL_GPL(perf_pmu_register);
9230 void perf_pmu_unregister(struct pmu *pmu)
9234 mutex_lock(&pmus_lock);
9235 remove_device = pmu_bus_running;
9236 list_del_rcu(&pmu->entry);
9237 mutex_unlock(&pmus_lock);
9240 * We dereference the pmu list under both SRCU and regular RCU, so
9241 * synchronize against both of those.
9243 synchronize_srcu(&pmus_srcu);
9246 free_percpu(pmu->pmu_disable_count);
9247 if (pmu->type >= PERF_TYPE_MAX)
9248 idr_remove(&pmu_idr, pmu->type);
9249 if (remove_device) {
9250 if (pmu->nr_addr_filters)
9251 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9252 device_del(pmu->dev);
9253 put_device(pmu->dev);
9255 free_pmu_context(pmu);
9257 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9259 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9261 struct perf_event_context *ctx = NULL;
9264 if (!try_module_get(pmu->module))
9267 if (event->group_leader != event) {
9269 * This ctx->mutex can nest when we're called through
9270 * inheritance. See the perf_event_ctx_lock_nested() comment.
9272 ctx = perf_event_ctx_lock_nested(event->group_leader,
9273 SINGLE_DEPTH_NESTING);
9278 ret = pmu->event_init(event);
9281 perf_event_ctx_unlock(event->group_leader, ctx);
9284 module_put(pmu->module);
9289 static struct pmu *perf_init_event(struct perf_event *event)
9295 idx = srcu_read_lock(&pmus_srcu);
9297 /* Try parent's PMU first: */
9298 if (event->parent && event->parent->pmu) {
9299 pmu = event->parent->pmu;
9300 ret = perf_try_init_event(pmu, event);
9306 pmu = idr_find(&pmu_idr, event->attr.type);
9309 ret = perf_try_init_event(pmu, event);
9315 list_for_each_entry_rcu(pmu, &pmus, entry) {
9316 ret = perf_try_init_event(pmu, event);
9320 if (ret != -ENOENT) {
9325 pmu = ERR_PTR(-ENOENT);
9327 srcu_read_unlock(&pmus_srcu, idx);
9332 static void attach_sb_event(struct perf_event *event)
9334 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9336 raw_spin_lock(&pel->lock);
9337 list_add_rcu(&event->sb_list, &pel->list);
9338 raw_spin_unlock(&pel->lock);
9342 * We keep a list of all !task (and therefore per-cpu) events
9343 * that need to receive side-band records.
9345 * This avoids having to scan all the various PMU per-cpu contexts
9348 static void account_pmu_sb_event(struct perf_event *event)
9350 if (is_sb_event(event))
9351 attach_sb_event(event);
9354 static void account_event_cpu(struct perf_event *event, int cpu)
9359 if (is_cgroup_event(event))
9360 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9363 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9364 static void account_freq_event_nohz(void)
9366 #ifdef CONFIG_NO_HZ_FULL
9367 /* Lock so we don't race with concurrent unaccount */
9368 spin_lock(&nr_freq_lock);
9369 if (atomic_inc_return(&nr_freq_events) == 1)
9370 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9371 spin_unlock(&nr_freq_lock);
9375 static void account_freq_event(void)
9377 if (tick_nohz_full_enabled())
9378 account_freq_event_nohz();
9380 atomic_inc(&nr_freq_events);
9384 static void account_event(struct perf_event *event)
9391 if (event->attach_state & PERF_ATTACH_TASK)
9393 if (event->attr.mmap || event->attr.mmap_data)
9394 atomic_inc(&nr_mmap_events);
9395 if (event->attr.comm)
9396 atomic_inc(&nr_comm_events);
9397 if (event->attr.namespaces)
9398 atomic_inc(&nr_namespaces_events);
9399 if (event->attr.task)
9400 atomic_inc(&nr_task_events);
9401 if (event->attr.freq)
9402 account_freq_event();
9403 if (event->attr.context_switch) {
9404 atomic_inc(&nr_switch_events);
9407 if (has_branch_stack(event))
9409 if (is_cgroup_event(event))
9413 if (atomic_inc_not_zero(&perf_sched_count))
9416 mutex_lock(&perf_sched_mutex);
9417 if (!atomic_read(&perf_sched_count)) {
9418 static_branch_enable(&perf_sched_events);
9420 * Guarantee that all CPUs observe they key change and
9421 * call the perf scheduling hooks before proceeding to
9422 * install events that need them.
9424 synchronize_sched();
9427 * Now that we have waited for the sync_sched(), allow further
9428 * increments to by-pass the mutex.
9430 atomic_inc(&perf_sched_count);
9431 mutex_unlock(&perf_sched_mutex);
9435 account_event_cpu(event, event->cpu);
9437 account_pmu_sb_event(event);
9441 * Allocate and initialize a event structure
9443 static struct perf_event *
9444 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9445 struct task_struct *task,
9446 struct perf_event *group_leader,
9447 struct perf_event *parent_event,
9448 perf_overflow_handler_t overflow_handler,
9449 void *context, int cgroup_fd)
9452 struct perf_event *event;
9453 struct hw_perf_event *hwc;
9456 if ((unsigned)cpu >= nr_cpu_ids) {
9457 if (!task || cpu != -1)
9458 return ERR_PTR(-EINVAL);
9461 event = kzalloc(sizeof(*event), GFP_KERNEL);
9463 return ERR_PTR(-ENOMEM);
9466 * Single events are their own group leaders, with an
9467 * empty sibling list:
9470 group_leader = event;
9472 mutex_init(&event->child_mutex);
9473 INIT_LIST_HEAD(&event->child_list);
9475 INIT_LIST_HEAD(&event->group_entry);
9476 INIT_LIST_HEAD(&event->event_entry);
9477 INIT_LIST_HEAD(&event->sibling_list);
9478 INIT_LIST_HEAD(&event->rb_entry);
9479 INIT_LIST_HEAD(&event->active_entry);
9480 INIT_LIST_HEAD(&event->addr_filters.list);
9481 INIT_HLIST_NODE(&event->hlist_entry);
9484 init_waitqueue_head(&event->waitq);
9485 init_irq_work(&event->pending, perf_pending_event);
9487 mutex_init(&event->mmap_mutex);
9488 raw_spin_lock_init(&event->addr_filters.lock);
9490 atomic_long_set(&event->refcount, 1);
9492 event->attr = *attr;
9493 event->group_leader = group_leader;
9497 event->parent = parent_event;
9499 event->ns = get_pid_ns(task_active_pid_ns(current));
9500 event->id = atomic64_inc_return(&perf_event_id);
9502 event->state = PERF_EVENT_STATE_INACTIVE;
9505 event->attach_state = PERF_ATTACH_TASK;
9507 * XXX pmu::event_init needs to know what task to account to
9508 * and we cannot use the ctx information because we need the
9509 * pmu before we get a ctx.
9511 event->hw.target = task;
9514 event->clock = &local_clock;
9516 event->clock = parent_event->clock;
9518 if (!overflow_handler && parent_event) {
9519 overflow_handler = parent_event->overflow_handler;
9520 context = parent_event->overflow_handler_context;
9521 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9522 if (overflow_handler == bpf_overflow_handler) {
9523 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9526 err = PTR_ERR(prog);
9530 event->orig_overflow_handler =
9531 parent_event->orig_overflow_handler;
9536 if (overflow_handler) {
9537 event->overflow_handler = overflow_handler;
9538 event->overflow_handler_context = context;
9539 } else if (is_write_backward(event)){
9540 event->overflow_handler = perf_event_output_backward;
9541 event->overflow_handler_context = NULL;
9543 event->overflow_handler = perf_event_output_forward;
9544 event->overflow_handler_context = NULL;
9547 perf_event__state_init(event);
9552 hwc->sample_period = attr->sample_period;
9553 if (attr->freq && attr->sample_freq)
9554 hwc->sample_period = 1;
9555 hwc->last_period = hwc->sample_period;
9557 local64_set(&hwc->period_left, hwc->sample_period);
9560 * We currently do not support PERF_SAMPLE_READ on inherited events.
9561 * See perf_output_read().
9563 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9566 if (!has_branch_stack(event))
9567 event->attr.branch_sample_type = 0;
9569 if (cgroup_fd != -1) {
9570 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9575 pmu = perf_init_event(event);
9581 err = exclusive_event_init(event);
9585 if (has_addr_filter(event)) {
9586 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9587 sizeof(unsigned long),
9589 if (!event->addr_filters_offs) {
9594 /* force hw sync on the address filters */
9595 event->addr_filters_gen = 1;
9598 if (!event->parent) {
9599 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9600 err = get_callchain_buffers(attr->sample_max_stack);
9602 goto err_addr_filters;
9606 /* symmetric to unaccount_event() in _free_event() */
9607 account_event(event);
9612 kfree(event->addr_filters_offs);
9615 exclusive_event_destroy(event);
9619 event->destroy(event);
9620 module_put(pmu->module);
9622 if (is_cgroup_event(event))
9623 perf_detach_cgroup(event);
9625 put_pid_ns(event->ns);
9628 return ERR_PTR(err);
9631 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9632 struct perf_event_attr *attr)
9637 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9641 * zero the full structure, so that a short copy will be nice.
9643 memset(attr, 0, sizeof(*attr));
9645 ret = get_user(size, &uattr->size);
9649 if (size > PAGE_SIZE) /* silly large */
9652 if (!size) /* abi compat */
9653 size = PERF_ATTR_SIZE_VER0;
9655 if (size < PERF_ATTR_SIZE_VER0)
9659 * If we're handed a bigger struct than we know of,
9660 * ensure all the unknown bits are 0 - i.e. new
9661 * user-space does not rely on any kernel feature
9662 * extensions we dont know about yet.
9664 if (size > sizeof(*attr)) {
9665 unsigned char __user *addr;
9666 unsigned char __user *end;
9669 addr = (void __user *)uattr + sizeof(*attr);
9670 end = (void __user *)uattr + size;
9672 for (; addr < end; addr++) {
9673 ret = get_user(val, addr);
9679 size = sizeof(*attr);
9682 ret = copy_from_user(attr, uattr, size);
9688 if (attr->__reserved_1)
9691 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9694 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9697 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9698 u64 mask = attr->branch_sample_type;
9700 /* only using defined bits */
9701 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9704 /* at least one branch bit must be set */
9705 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9708 /* propagate priv level, when not set for branch */
9709 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9711 /* exclude_kernel checked on syscall entry */
9712 if (!attr->exclude_kernel)
9713 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9715 if (!attr->exclude_user)
9716 mask |= PERF_SAMPLE_BRANCH_USER;
9718 if (!attr->exclude_hv)
9719 mask |= PERF_SAMPLE_BRANCH_HV;
9721 * adjust user setting (for HW filter setup)
9723 attr->branch_sample_type = mask;
9725 /* privileged levels capture (kernel, hv): check permissions */
9726 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9727 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9731 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9732 ret = perf_reg_validate(attr->sample_regs_user);
9737 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9738 if (!arch_perf_have_user_stack_dump())
9742 * We have __u32 type for the size, but so far
9743 * we can only use __u16 as maximum due to the
9744 * __u16 sample size limit.
9746 if (attr->sample_stack_user >= USHRT_MAX)
9748 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9752 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9753 ret = perf_reg_validate(attr->sample_regs_intr);
9758 put_user(sizeof(*attr), &uattr->size);
9764 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9766 struct ring_buffer *rb = NULL;
9772 /* don't allow circular references */
9773 if (event == output_event)
9777 * Don't allow cross-cpu buffers
9779 if (output_event->cpu != event->cpu)
9783 * If its not a per-cpu rb, it must be the same task.
9785 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9789 * Mixing clocks in the same buffer is trouble you don't need.
9791 if (output_event->clock != event->clock)
9795 * Either writing ring buffer from beginning or from end.
9796 * Mixing is not allowed.
9798 if (is_write_backward(output_event) != is_write_backward(event))
9802 * If both events generate aux data, they must be on the same PMU
9804 if (has_aux(event) && has_aux(output_event) &&
9805 event->pmu != output_event->pmu)
9809 mutex_lock(&event->mmap_mutex);
9810 /* Can't redirect output if we've got an active mmap() */
9811 if (atomic_read(&event->mmap_count))
9815 /* get the rb we want to redirect to */
9816 rb = ring_buffer_get(output_event);
9821 ring_buffer_attach(event, rb);
9825 mutex_unlock(&event->mmap_mutex);
9831 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9837 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9840 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9842 bool nmi_safe = false;
9845 case CLOCK_MONOTONIC:
9846 event->clock = &ktime_get_mono_fast_ns;
9850 case CLOCK_MONOTONIC_RAW:
9851 event->clock = &ktime_get_raw_fast_ns;
9855 case CLOCK_REALTIME:
9856 event->clock = &ktime_get_real_ns;
9859 case CLOCK_BOOTTIME:
9860 event->clock = &ktime_get_boot_ns;
9864 event->clock = &ktime_get_tai_ns;
9871 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9878 * Variation on perf_event_ctx_lock_nested(), except we take two context
9881 static struct perf_event_context *
9882 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9883 struct perf_event_context *ctx)
9885 struct perf_event_context *gctx;
9889 gctx = READ_ONCE(group_leader->ctx);
9890 if (!atomic_inc_not_zero(&gctx->refcount)) {
9896 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9898 if (group_leader->ctx != gctx) {
9899 mutex_unlock(&ctx->mutex);
9900 mutex_unlock(&gctx->mutex);
9909 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9911 * @attr_uptr: event_id type attributes for monitoring/sampling
9914 * @group_fd: group leader event fd
9916 SYSCALL_DEFINE5(perf_event_open,
9917 struct perf_event_attr __user *, attr_uptr,
9918 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9920 struct perf_event *group_leader = NULL, *output_event = NULL;
9921 struct perf_event *event, *sibling;
9922 struct perf_event_attr attr;
9923 struct perf_event_context *ctx, *uninitialized_var(gctx);
9924 struct file *event_file = NULL;
9925 struct fd group = {NULL, 0};
9926 struct task_struct *task = NULL;
9931 int f_flags = O_RDWR;
9934 /* for future expandability... */
9935 if (flags & ~PERF_FLAG_ALL)
9938 err = perf_copy_attr(attr_uptr, &attr);
9942 if (!attr.exclude_kernel) {
9943 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9947 if (attr.namespaces) {
9948 if (!capable(CAP_SYS_ADMIN))
9953 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9956 if (attr.sample_period & (1ULL << 63))
9960 /* Only privileged users can get physical addresses */
9961 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
9962 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9965 if (!attr.sample_max_stack)
9966 attr.sample_max_stack = sysctl_perf_event_max_stack;
9969 * In cgroup mode, the pid argument is used to pass the fd
9970 * opened to the cgroup directory in cgroupfs. The cpu argument
9971 * designates the cpu on which to monitor threads from that
9974 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9977 if (flags & PERF_FLAG_FD_CLOEXEC)
9978 f_flags |= O_CLOEXEC;
9980 event_fd = get_unused_fd_flags(f_flags);
9984 if (group_fd != -1) {
9985 err = perf_fget_light(group_fd, &group);
9988 group_leader = group.file->private_data;
9989 if (flags & PERF_FLAG_FD_OUTPUT)
9990 output_event = group_leader;
9991 if (flags & PERF_FLAG_FD_NO_GROUP)
9992 group_leader = NULL;
9995 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9996 task = find_lively_task_by_vpid(pid);
9998 err = PTR_ERR(task);
10003 if (task && group_leader &&
10004 group_leader->attr.inherit != attr.inherit) {
10010 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10015 * Reuse ptrace permission checks for now.
10017 * We must hold cred_guard_mutex across this and any potential
10018 * perf_install_in_context() call for this new event to
10019 * serialize against exec() altering our credentials (and the
10020 * perf_event_exit_task() that could imply).
10023 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10027 if (flags & PERF_FLAG_PID_CGROUP)
10030 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10031 NULL, NULL, cgroup_fd);
10032 if (IS_ERR(event)) {
10033 err = PTR_ERR(event);
10037 if (is_sampling_event(event)) {
10038 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10045 * Special case software events and allow them to be part of
10046 * any hardware group.
10050 if (attr.use_clockid) {
10051 err = perf_event_set_clock(event, attr.clockid);
10056 if (pmu->task_ctx_nr == perf_sw_context)
10057 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10059 if (group_leader &&
10060 (is_software_event(event) != is_software_event(group_leader))) {
10061 if (is_software_event(event)) {
10063 * If event and group_leader are not both a software
10064 * event, and event is, then group leader is not.
10066 * Allow the addition of software events to !software
10067 * groups, this is safe because software events never
10068 * fail to schedule.
10070 pmu = group_leader->pmu;
10071 } else if (is_software_event(group_leader) &&
10072 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10074 * In case the group is a pure software group, and we
10075 * try to add a hardware event, move the whole group to
10076 * the hardware context.
10083 * Get the target context (task or percpu):
10085 ctx = find_get_context(pmu, task, event);
10087 err = PTR_ERR(ctx);
10091 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10097 * Look up the group leader (we will attach this event to it):
10099 if (group_leader) {
10103 * Do not allow a recursive hierarchy (this new sibling
10104 * becoming part of another group-sibling):
10106 if (group_leader->group_leader != group_leader)
10109 /* All events in a group should have the same clock */
10110 if (group_leader->clock != event->clock)
10114 * Make sure we're both events for the same CPU;
10115 * grouping events for different CPUs is broken; since
10116 * you can never concurrently schedule them anyhow.
10118 if (group_leader->cpu != event->cpu)
10122 * Make sure we're both on the same task, or both
10125 if (group_leader->ctx->task != ctx->task)
10129 * Do not allow to attach to a group in a different task
10130 * or CPU context. If we're moving SW events, we'll fix
10131 * this up later, so allow that.
10133 if (!move_group && group_leader->ctx != ctx)
10137 * Only a group leader can be exclusive or pinned
10139 if (attr.exclusive || attr.pinned)
10143 if (output_event) {
10144 err = perf_event_set_output(event, output_event);
10149 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10151 if (IS_ERR(event_file)) {
10152 err = PTR_ERR(event_file);
10158 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10160 if (gctx->task == TASK_TOMBSTONE) {
10166 * Check if we raced against another sys_perf_event_open() call
10167 * moving the software group underneath us.
10169 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10171 * If someone moved the group out from under us, check
10172 * if this new event wound up on the same ctx, if so
10173 * its the regular !move_group case, otherwise fail.
10179 perf_event_ctx_unlock(group_leader, gctx);
10184 mutex_lock(&ctx->mutex);
10187 if (ctx->task == TASK_TOMBSTONE) {
10192 if (!perf_event_validate_size(event)) {
10199 * Check if the @cpu we're creating an event for is online.
10201 * We use the perf_cpu_context::ctx::mutex to serialize against
10202 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10204 struct perf_cpu_context *cpuctx =
10205 container_of(ctx, struct perf_cpu_context, ctx);
10207 if (!cpuctx->online) {
10215 * Must be under the same ctx::mutex as perf_install_in_context(),
10216 * because we need to serialize with concurrent event creation.
10218 if (!exclusive_event_installable(event, ctx)) {
10219 /* exclusive and group stuff are assumed mutually exclusive */
10220 WARN_ON_ONCE(move_group);
10226 WARN_ON_ONCE(ctx->parent_ctx);
10229 * This is the point on no return; we cannot fail hereafter. This is
10230 * where we start modifying current state.
10235 * See perf_event_ctx_lock() for comments on the details
10236 * of swizzling perf_event::ctx.
10238 perf_remove_from_context(group_leader, 0);
10241 list_for_each_entry(sibling, &group_leader->sibling_list,
10243 perf_remove_from_context(sibling, 0);
10248 * Wait for everybody to stop referencing the events through
10249 * the old lists, before installing it on new lists.
10254 * Install the group siblings before the group leader.
10256 * Because a group leader will try and install the entire group
10257 * (through the sibling list, which is still in-tact), we can
10258 * end up with siblings installed in the wrong context.
10260 * By installing siblings first we NO-OP because they're not
10261 * reachable through the group lists.
10263 list_for_each_entry(sibling, &group_leader->sibling_list,
10265 perf_event__state_init(sibling);
10266 perf_install_in_context(ctx, sibling, sibling->cpu);
10271 * Removing from the context ends up with disabled
10272 * event. What we want here is event in the initial
10273 * startup state, ready to be add into new context.
10275 perf_event__state_init(group_leader);
10276 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10281 * Precalculate sample_data sizes; do while holding ctx::mutex such
10282 * that we're serialized against further additions and before
10283 * perf_install_in_context() which is the point the event is active and
10284 * can use these values.
10286 perf_event__header_size(event);
10287 perf_event__id_header_size(event);
10289 event->owner = current;
10291 perf_install_in_context(ctx, event, event->cpu);
10292 perf_unpin_context(ctx);
10295 perf_event_ctx_unlock(group_leader, gctx);
10296 mutex_unlock(&ctx->mutex);
10299 mutex_unlock(&task->signal->cred_guard_mutex);
10300 put_task_struct(task);
10303 mutex_lock(¤t->perf_event_mutex);
10304 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10305 mutex_unlock(¤t->perf_event_mutex);
10308 * Drop the reference on the group_event after placing the
10309 * new event on the sibling_list. This ensures destruction
10310 * of the group leader will find the pointer to itself in
10311 * perf_group_detach().
10314 fd_install(event_fd, event_file);
10319 perf_event_ctx_unlock(group_leader, gctx);
10320 mutex_unlock(&ctx->mutex);
10324 perf_unpin_context(ctx);
10328 * If event_file is set, the fput() above will have called ->release()
10329 * and that will take care of freeing the event.
10335 mutex_unlock(&task->signal->cred_guard_mutex);
10338 put_task_struct(task);
10342 put_unused_fd(event_fd);
10347 * perf_event_create_kernel_counter
10349 * @attr: attributes of the counter to create
10350 * @cpu: cpu in which the counter is bound
10351 * @task: task to profile (NULL for percpu)
10353 struct perf_event *
10354 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10355 struct task_struct *task,
10356 perf_overflow_handler_t overflow_handler,
10359 struct perf_event_context *ctx;
10360 struct perf_event *event;
10364 * Get the target context (task or percpu):
10367 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10368 overflow_handler, context, -1);
10369 if (IS_ERR(event)) {
10370 err = PTR_ERR(event);
10374 /* Mark owner so we could distinguish it from user events. */
10375 event->owner = TASK_TOMBSTONE;
10377 ctx = find_get_context(event->pmu, task, event);
10379 err = PTR_ERR(ctx);
10383 WARN_ON_ONCE(ctx->parent_ctx);
10384 mutex_lock(&ctx->mutex);
10385 if (ctx->task == TASK_TOMBSTONE) {
10392 * Check if the @cpu we're creating an event for is online.
10394 * We use the perf_cpu_context::ctx::mutex to serialize against
10395 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10397 struct perf_cpu_context *cpuctx =
10398 container_of(ctx, struct perf_cpu_context, ctx);
10399 if (!cpuctx->online) {
10405 if (!exclusive_event_installable(event, ctx)) {
10410 perf_install_in_context(ctx, event, cpu);
10411 perf_unpin_context(ctx);
10412 mutex_unlock(&ctx->mutex);
10417 mutex_unlock(&ctx->mutex);
10418 perf_unpin_context(ctx);
10423 return ERR_PTR(err);
10425 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10427 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10429 struct perf_event_context *src_ctx;
10430 struct perf_event_context *dst_ctx;
10431 struct perf_event *event, *tmp;
10434 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10435 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10438 * See perf_event_ctx_lock() for comments on the details
10439 * of swizzling perf_event::ctx.
10441 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10442 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10444 perf_remove_from_context(event, 0);
10445 unaccount_event_cpu(event, src_cpu);
10447 list_add(&event->migrate_entry, &events);
10451 * Wait for the events to quiesce before re-instating them.
10456 * Re-instate events in 2 passes.
10458 * Skip over group leaders and only install siblings on this first
10459 * pass, siblings will not get enabled without a leader, however a
10460 * leader will enable its siblings, even if those are still on the old
10463 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10464 if (event->group_leader == event)
10467 list_del(&event->migrate_entry);
10468 if (event->state >= PERF_EVENT_STATE_OFF)
10469 event->state = PERF_EVENT_STATE_INACTIVE;
10470 account_event_cpu(event, dst_cpu);
10471 perf_install_in_context(dst_ctx, event, dst_cpu);
10476 * Once all the siblings are setup properly, install the group leaders
10479 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10480 list_del(&event->migrate_entry);
10481 if (event->state >= PERF_EVENT_STATE_OFF)
10482 event->state = PERF_EVENT_STATE_INACTIVE;
10483 account_event_cpu(event, dst_cpu);
10484 perf_install_in_context(dst_ctx, event, dst_cpu);
10487 mutex_unlock(&dst_ctx->mutex);
10488 mutex_unlock(&src_ctx->mutex);
10490 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10492 static void sync_child_event(struct perf_event *child_event,
10493 struct task_struct *child)
10495 struct perf_event *parent_event = child_event->parent;
10498 if (child_event->attr.inherit_stat)
10499 perf_event_read_event(child_event, child);
10501 child_val = perf_event_count(child_event);
10504 * Add back the child's count to the parent's count:
10506 atomic64_add(child_val, &parent_event->child_count);
10507 atomic64_add(child_event->total_time_enabled,
10508 &parent_event->child_total_time_enabled);
10509 atomic64_add(child_event->total_time_running,
10510 &parent_event->child_total_time_running);
10514 perf_event_exit_event(struct perf_event *child_event,
10515 struct perf_event_context *child_ctx,
10516 struct task_struct *child)
10518 struct perf_event *parent_event = child_event->parent;
10521 * Do not destroy the 'original' grouping; because of the context
10522 * switch optimization the original events could've ended up in a
10523 * random child task.
10525 * If we were to destroy the original group, all group related
10526 * operations would cease to function properly after this random
10529 * Do destroy all inherited groups, we don't care about those
10530 * and being thorough is better.
10532 raw_spin_lock_irq(&child_ctx->lock);
10533 WARN_ON_ONCE(child_ctx->is_active);
10536 perf_group_detach(child_event);
10537 list_del_event(child_event, child_ctx);
10538 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10539 raw_spin_unlock_irq(&child_ctx->lock);
10542 * Parent events are governed by their filedesc, retain them.
10544 if (!parent_event) {
10545 perf_event_wakeup(child_event);
10549 * Child events can be cleaned up.
10552 sync_child_event(child_event, child);
10555 * Remove this event from the parent's list
10557 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10558 mutex_lock(&parent_event->child_mutex);
10559 list_del_init(&child_event->child_list);
10560 mutex_unlock(&parent_event->child_mutex);
10563 * Kick perf_poll() for is_event_hup().
10565 perf_event_wakeup(parent_event);
10566 free_event(child_event);
10567 put_event(parent_event);
10570 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10572 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10573 struct perf_event *child_event, *next;
10575 WARN_ON_ONCE(child != current);
10577 child_ctx = perf_pin_task_context(child, ctxn);
10582 * In order to reduce the amount of tricky in ctx tear-down, we hold
10583 * ctx::mutex over the entire thing. This serializes against almost
10584 * everything that wants to access the ctx.
10586 * The exception is sys_perf_event_open() /
10587 * perf_event_create_kernel_count() which does find_get_context()
10588 * without ctx::mutex (it cannot because of the move_group double mutex
10589 * lock thing). See the comments in perf_install_in_context().
10591 mutex_lock(&child_ctx->mutex);
10594 * In a single ctx::lock section, de-schedule the events and detach the
10595 * context from the task such that we cannot ever get it scheduled back
10598 raw_spin_lock_irq(&child_ctx->lock);
10599 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10602 * Now that the context is inactive, destroy the task <-> ctx relation
10603 * and mark the context dead.
10605 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10606 put_ctx(child_ctx); /* cannot be last */
10607 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10608 put_task_struct(current); /* cannot be last */
10610 clone_ctx = unclone_ctx(child_ctx);
10611 raw_spin_unlock_irq(&child_ctx->lock);
10614 put_ctx(clone_ctx);
10617 * Report the task dead after unscheduling the events so that we
10618 * won't get any samples after PERF_RECORD_EXIT. We can however still
10619 * get a few PERF_RECORD_READ events.
10621 perf_event_task(child, child_ctx, 0);
10623 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10624 perf_event_exit_event(child_event, child_ctx, child);
10626 mutex_unlock(&child_ctx->mutex);
10628 put_ctx(child_ctx);
10632 * When a child task exits, feed back event values to parent events.
10634 * Can be called with cred_guard_mutex held when called from
10635 * install_exec_creds().
10637 void perf_event_exit_task(struct task_struct *child)
10639 struct perf_event *event, *tmp;
10642 mutex_lock(&child->perf_event_mutex);
10643 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10645 list_del_init(&event->owner_entry);
10648 * Ensure the list deletion is visible before we clear
10649 * the owner, closes a race against perf_release() where
10650 * we need to serialize on the owner->perf_event_mutex.
10652 smp_store_release(&event->owner, NULL);
10654 mutex_unlock(&child->perf_event_mutex);
10656 for_each_task_context_nr(ctxn)
10657 perf_event_exit_task_context(child, ctxn);
10660 * The perf_event_exit_task_context calls perf_event_task
10661 * with child's task_ctx, which generates EXIT events for
10662 * child contexts and sets child->perf_event_ctxp[] to NULL.
10663 * At this point we need to send EXIT events to cpu contexts.
10665 perf_event_task(child, NULL, 0);
10668 static void perf_free_event(struct perf_event *event,
10669 struct perf_event_context *ctx)
10671 struct perf_event *parent = event->parent;
10673 if (WARN_ON_ONCE(!parent))
10676 mutex_lock(&parent->child_mutex);
10677 list_del_init(&event->child_list);
10678 mutex_unlock(&parent->child_mutex);
10682 raw_spin_lock_irq(&ctx->lock);
10683 perf_group_detach(event);
10684 list_del_event(event, ctx);
10685 raw_spin_unlock_irq(&ctx->lock);
10690 * Free an unexposed, unused context as created by inheritance by
10691 * perf_event_init_task below, used by fork() in case of fail.
10693 * Not all locks are strictly required, but take them anyway to be nice and
10694 * help out with the lockdep assertions.
10696 void perf_event_free_task(struct task_struct *task)
10698 struct perf_event_context *ctx;
10699 struct perf_event *event, *tmp;
10702 for_each_task_context_nr(ctxn) {
10703 ctx = task->perf_event_ctxp[ctxn];
10707 mutex_lock(&ctx->mutex);
10708 raw_spin_lock_irq(&ctx->lock);
10710 * Destroy the task <-> ctx relation and mark the context dead.
10712 * This is important because even though the task hasn't been
10713 * exposed yet the context has been (through child_list).
10715 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10716 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10717 put_task_struct(task); /* cannot be last */
10718 raw_spin_unlock_irq(&ctx->lock);
10720 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10721 perf_free_event(event, ctx);
10723 mutex_unlock(&ctx->mutex);
10728 void perf_event_delayed_put(struct task_struct *task)
10732 for_each_task_context_nr(ctxn)
10733 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10736 struct file *perf_event_get(unsigned int fd)
10740 file = fget_raw(fd);
10742 return ERR_PTR(-EBADF);
10744 if (file->f_op != &perf_fops) {
10746 return ERR_PTR(-EBADF);
10752 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10755 return ERR_PTR(-EINVAL);
10757 return &event->attr;
10761 * Inherit a event from parent task to child task.
10764 * - valid pointer on success
10765 * - NULL for orphaned events
10766 * - IS_ERR() on error
10768 static struct perf_event *
10769 inherit_event(struct perf_event *parent_event,
10770 struct task_struct *parent,
10771 struct perf_event_context *parent_ctx,
10772 struct task_struct *child,
10773 struct perf_event *group_leader,
10774 struct perf_event_context *child_ctx)
10776 enum perf_event_active_state parent_state = parent_event->state;
10777 struct perf_event *child_event;
10778 unsigned long flags;
10781 * Instead of creating recursive hierarchies of events,
10782 * we link inherited events back to the original parent,
10783 * which has a filp for sure, which we use as the reference
10786 if (parent_event->parent)
10787 parent_event = parent_event->parent;
10789 child_event = perf_event_alloc(&parent_event->attr,
10792 group_leader, parent_event,
10794 if (IS_ERR(child_event))
10795 return child_event;
10798 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10799 * must be under the same lock in order to serialize against
10800 * perf_event_release_kernel(), such that either we must observe
10801 * is_orphaned_event() or they will observe us on the child_list.
10803 mutex_lock(&parent_event->child_mutex);
10804 if (is_orphaned_event(parent_event) ||
10805 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10806 mutex_unlock(&parent_event->child_mutex);
10807 free_event(child_event);
10811 get_ctx(child_ctx);
10814 * Make the child state follow the state of the parent event,
10815 * not its attr.disabled bit. We hold the parent's mutex,
10816 * so we won't race with perf_event_{en, dis}able_family.
10818 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10819 child_event->state = PERF_EVENT_STATE_INACTIVE;
10821 child_event->state = PERF_EVENT_STATE_OFF;
10823 if (parent_event->attr.freq) {
10824 u64 sample_period = parent_event->hw.sample_period;
10825 struct hw_perf_event *hwc = &child_event->hw;
10827 hwc->sample_period = sample_period;
10828 hwc->last_period = sample_period;
10830 local64_set(&hwc->period_left, sample_period);
10833 child_event->ctx = child_ctx;
10834 child_event->overflow_handler = parent_event->overflow_handler;
10835 child_event->overflow_handler_context
10836 = parent_event->overflow_handler_context;
10839 * Precalculate sample_data sizes
10841 perf_event__header_size(child_event);
10842 perf_event__id_header_size(child_event);
10845 * Link it up in the child's context:
10847 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10848 add_event_to_ctx(child_event, child_ctx);
10849 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10852 * Link this into the parent event's child list
10854 list_add_tail(&child_event->child_list, &parent_event->child_list);
10855 mutex_unlock(&parent_event->child_mutex);
10857 return child_event;
10861 * Inherits an event group.
10863 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10864 * This matches with perf_event_release_kernel() removing all child events.
10870 static int inherit_group(struct perf_event *parent_event,
10871 struct task_struct *parent,
10872 struct perf_event_context *parent_ctx,
10873 struct task_struct *child,
10874 struct perf_event_context *child_ctx)
10876 struct perf_event *leader;
10877 struct perf_event *sub;
10878 struct perf_event *child_ctr;
10880 leader = inherit_event(parent_event, parent, parent_ctx,
10881 child, NULL, child_ctx);
10882 if (IS_ERR(leader))
10883 return PTR_ERR(leader);
10885 * @leader can be NULL here because of is_orphaned_event(). In this
10886 * case inherit_event() will create individual events, similar to what
10887 * perf_group_detach() would do anyway.
10889 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10890 child_ctr = inherit_event(sub, parent, parent_ctx,
10891 child, leader, child_ctx);
10892 if (IS_ERR(child_ctr))
10893 return PTR_ERR(child_ctr);
10899 * Creates the child task context and tries to inherit the event-group.
10901 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10902 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10903 * consistent with perf_event_release_kernel() removing all child events.
10910 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10911 struct perf_event_context *parent_ctx,
10912 struct task_struct *child, int ctxn,
10913 int *inherited_all)
10916 struct perf_event_context *child_ctx;
10918 if (!event->attr.inherit) {
10919 *inherited_all = 0;
10923 child_ctx = child->perf_event_ctxp[ctxn];
10926 * This is executed from the parent task context, so
10927 * inherit events that have been marked for cloning.
10928 * First allocate and initialize a context for the
10931 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10935 child->perf_event_ctxp[ctxn] = child_ctx;
10938 ret = inherit_group(event, parent, parent_ctx,
10942 *inherited_all = 0;
10948 * Initialize the perf_event context in task_struct
10950 static int perf_event_init_context(struct task_struct *child, int ctxn)
10952 struct perf_event_context *child_ctx, *parent_ctx;
10953 struct perf_event_context *cloned_ctx;
10954 struct perf_event *event;
10955 struct task_struct *parent = current;
10956 int inherited_all = 1;
10957 unsigned long flags;
10960 if (likely(!parent->perf_event_ctxp[ctxn]))
10964 * If the parent's context is a clone, pin it so it won't get
10965 * swapped under us.
10967 parent_ctx = perf_pin_task_context(parent, ctxn);
10972 * No need to check if parent_ctx != NULL here; since we saw
10973 * it non-NULL earlier, the only reason for it to become NULL
10974 * is if we exit, and since we're currently in the middle of
10975 * a fork we can't be exiting at the same time.
10979 * Lock the parent list. No need to lock the child - not PID
10980 * hashed yet and not running, so nobody can access it.
10982 mutex_lock(&parent_ctx->mutex);
10985 * We dont have to disable NMIs - we are only looking at
10986 * the list, not manipulating it:
10988 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10989 ret = inherit_task_group(event, parent, parent_ctx,
10990 child, ctxn, &inherited_all);
10996 * We can't hold ctx->lock when iterating the ->flexible_group list due
10997 * to allocations, but we need to prevent rotation because
10998 * rotate_ctx() will change the list from interrupt context.
11000 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11001 parent_ctx->rotate_disable = 1;
11002 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11004 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
11005 ret = inherit_task_group(event, parent, parent_ctx,
11006 child, ctxn, &inherited_all);
11011 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11012 parent_ctx->rotate_disable = 0;
11014 child_ctx = child->perf_event_ctxp[ctxn];
11016 if (child_ctx && inherited_all) {
11018 * Mark the child context as a clone of the parent
11019 * context, or of whatever the parent is a clone of.
11021 * Note that if the parent is a clone, the holding of
11022 * parent_ctx->lock avoids it from being uncloned.
11024 cloned_ctx = parent_ctx->parent_ctx;
11026 child_ctx->parent_ctx = cloned_ctx;
11027 child_ctx->parent_gen = parent_ctx->parent_gen;
11029 child_ctx->parent_ctx = parent_ctx;
11030 child_ctx->parent_gen = parent_ctx->generation;
11032 get_ctx(child_ctx->parent_ctx);
11035 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11037 mutex_unlock(&parent_ctx->mutex);
11039 perf_unpin_context(parent_ctx);
11040 put_ctx(parent_ctx);
11046 * Initialize the perf_event context in task_struct
11048 int perf_event_init_task(struct task_struct *child)
11052 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11053 mutex_init(&child->perf_event_mutex);
11054 INIT_LIST_HEAD(&child->perf_event_list);
11056 for_each_task_context_nr(ctxn) {
11057 ret = perf_event_init_context(child, ctxn);
11059 perf_event_free_task(child);
11067 static void __init perf_event_init_all_cpus(void)
11069 struct swevent_htable *swhash;
11072 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11074 for_each_possible_cpu(cpu) {
11075 swhash = &per_cpu(swevent_htable, cpu);
11076 mutex_init(&swhash->hlist_mutex);
11077 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11079 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11080 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11082 #ifdef CONFIG_CGROUP_PERF
11083 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11085 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11089 void perf_swevent_init_cpu(unsigned int cpu)
11091 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11093 mutex_lock(&swhash->hlist_mutex);
11094 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11095 struct swevent_hlist *hlist;
11097 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11099 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11101 mutex_unlock(&swhash->hlist_mutex);
11104 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11105 static void __perf_event_exit_context(void *__info)
11107 struct perf_event_context *ctx = __info;
11108 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11109 struct perf_event *event;
11111 raw_spin_lock(&ctx->lock);
11112 list_for_each_entry(event, &ctx->event_list, event_entry)
11113 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11114 raw_spin_unlock(&ctx->lock);
11117 static void perf_event_exit_cpu_context(int cpu)
11119 struct perf_cpu_context *cpuctx;
11120 struct perf_event_context *ctx;
11123 mutex_lock(&pmus_lock);
11124 list_for_each_entry(pmu, &pmus, entry) {
11125 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11126 ctx = &cpuctx->ctx;
11128 mutex_lock(&ctx->mutex);
11129 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11130 cpuctx->online = 0;
11131 mutex_unlock(&ctx->mutex);
11133 cpumask_clear_cpu(cpu, perf_online_mask);
11134 mutex_unlock(&pmus_lock);
11138 static void perf_event_exit_cpu_context(int cpu) { }
11142 int perf_event_init_cpu(unsigned int cpu)
11144 struct perf_cpu_context *cpuctx;
11145 struct perf_event_context *ctx;
11148 perf_swevent_init_cpu(cpu);
11150 mutex_lock(&pmus_lock);
11151 cpumask_set_cpu(cpu, perf_online_mask);
11152 list_for_each_entry(pmu, &pmus, entry) {
11153 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11154 ctx = &cpuctx->ctx;
11156 mutex_lock(&ctx->mutex);
11157 cpuctx->online = 1;
11158 mutex_unlock(&ctx->mutex);
11160 mutex_unlock(&pmus_lock);
11165 int perf_event_exit_cpu(unsigned int cpu)
11167 perf_event_exit_cpu_context(cpu);
11172 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11176 for_each_online_cpu(cpu)
11177 perf_event_exit_cpu(cpu);
11183 * Run the perf reboot notifier at the very last possible moment so that
11184 * the generic watchdog code runs as long as possible.
11186 static struct notifier_block perf_reboot_notifier = {
11187 .notifier_call = perf_reboot,
11188 .priority = INT_MIN,
11191 void __init perf_event_init(void)
11195 idr_init(&pmu_idr);
11197 perf_event_init_all_cpus();
11198 init_srcu_struct(&pmus_srcu);
11199 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11200 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11201 perf_pmu_register(&perf_task_clock, NULL, -1);
11202 perf_tp_register();
11203 perf_event_init_cpu(smp_processor_id());
11204 register_reboot_notifier(&perf_reboot_notifier);
11206 ret = init_hw_breakpoint();
11207 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11210 * Build time assertion that we keep the data_head at the intended
11211 * location. IOW, validation we got the __reserved[] size right.
11213 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11217 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11220 struct perf_pmu_events_attr *pmu_attr =
11221 container_of(attr, struct perf_pmu_events_attr, attr);
11223 if (pmu_attr->event_str)
11224 return sprintf(page, "%s\n", pmu_attr->event_str);
11228 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11230 static int __init perf_event_sysfs_init(void)
11235 mutex_lock(&pmus_lock);
11237 ret = bus_register(&pmu_bus);
11241 list_for_each_entry(pmu, &pmus, entry) {
11242 if (!pmu->name || pmu->type < 0)
11245 ret = pmu_dev_alloc(pmu);
11246 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11248 pmu_bus_running = 1;
11252 mutex_unlock(&pmus_lock);
11256 device_initcall(perf_event_sysfs_init);
11258 #ifdef CONFIG_CGROUP_PERF
11259 static struct cgroup_subsys_state *
11260 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11262 struct perf_cgroup *jc;
11264 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11266 return ERR_PTR(-ENOMEM);
11268 jc->info = alloc_percpu(struct perf_cgroup_info);
11271 return ERR_PTR(-ENOMEM);
11277 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11279 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11281 free_percpu(jc->info);
11285 static int __perf_cgroup_move(void *info)
11287 struct task_struct *task = info;
11289 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11294 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11296 struct task_struct *task;
11297 struct cgroup_subsys_state *css;
11299 cgroup_taskset_for_each(task, css, tset)
11300 task_function_call(task, __perf_cgroup_move, task);
11303 struct cgroup_subsys perf_event_cgrp_subsys = {
11304 .css_alloc = perf_cgroup_css_alloc,
11305 .css_free = perf_cgroup_css_free,
11306 .attach = perf_cgroup_attach,
11308 * Implicitly enable on dfl hierarchy so that perf events can
11309 * always be filtered by cgroup2 path as long as perf_event
11310 * controller is not mounted on a legacy hierarchy.
11312 .implicit_on_dfl = true,
11315 #endif /* CONFIG_CGROUP_PERF */