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 (cgrp == event->cgrp)
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 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
905 if (perf_cgroup_from_task(current, ctx) == event->cgrp)
906 cpuctx->cgrp = event->cgrp;
908 list_del(cpuctx_entry);
913 #else /* !CONFIG_CGROUP_PERF */
916 perf_cgroup_match(struct perf_event *event)
921 static inline void perf_detach_cgroup(struct perf_event *event)
924 static inline int is_cgroup_event(struct perf_event *event)
929 static inline void update_cgrp_time_from_event(struct perf_event *event)
933 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
937 static inline void perf_cgroup_sched_out(struct task_struct *task,
938 struct task_struct *next)
942 static inline void perf_cgroup_sched_in(struct task_struct *prev,
943 struct task_struct *task)
947 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
948 struct perf_event_attr *attr,
949 struct perf_event *group_leader)
955 perf_cgroup_set_timestamp(struct task_struct *task,
956 struct perf_event_context *ctx)
961 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
966 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
970 static inline u64 perf_cgroup_event_time(struct perf_event *event)
976 perf_cgroup_defer_enabled(struct perf_event *event)
981 perf_cgroup_mark_enabled(struct perf_event *event,
982 struct perf_event_context *ctx)
987 list_update_cgroup_event(struct perf_event *event,
988 struct perf_event_context *ctx, bool add)
995 * set default to be dependent on timer tick just
998 #define PERF_CPU_HRTIMER (1000 / HZ)
1000 * function must be called with interrupts disabled
1002 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1004 struct perf_cpu_context *cpuctx;
1007 WARN_ON(!irqs_disabled());
1009 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1010 rotations = perf_rotate_context(cpuctx);
1012 raw_spin_lock(&cpuctx->hrtimer_lock);
1014 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1016 cpuctx->hrtimer_active = 0;
1017 raw_spin_unlock(&cpuctx->hrtimer_lock);
1019 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1022 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1024 struct hrtimer *timer = &cpuctx->hrtimer;
1025 struct pmu *pmu = cpuctx->ctx.pmu;
1028 /* no multiplexing needed for SW PMU */
1029 if (pmu->task_ctx_nr == perf_sw_context)
1033 * check default is sane, if not set then force to
1034 * default interval (1/tick)
1036 interval = pmu->hrtimer_interval_ms;
1038 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1040 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1042 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1043 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1044 timer->function = perf_mux_hrtimer_handler;
1047 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1049 struct hrtimer *timer = &cpuctx->hrtimer;
1050 struct pmu *pmu = cpuctx->ctx.pmu;
1051 unsigned long flags;
1053 /* not for SW PMU */
1054 if (pmu->task_ctx_nr == perf_sw_context)
1057 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1058 if (!cpuctx->hrtimer_active) {
1059 cpuctx->hrtimer_active = 1;
1060 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1061 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1063 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1068 void perf_pmu_disable(struct pmu *pmu)
1070 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1072 pmu->pmu_disable(pmu);
1075 void perf_pmu_enable(struct pmu *pmu)
1077 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1079 pmu->pmu_enable(pmu);
1082 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1085 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1086 * perf_event_task_tick() are fully serialized because they're strictly cpu
1087 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1088 * disabled, while perf_event_task_tick is called from IRQ context.
1090 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1092 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1094 WARN_ON(!irqs_disabled());
1096 WARN_ON(!list_empty(&ctx->active_ctx_list));
1098 list_add(&ctx->active_ctx_list, head);
1101 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1103 WARN_ON(!irqs_disabled());
1105 WARN_ON(list_empty(&ctx->active_ctx_list));
1107 list_del_init(&ctx->active_ctx_list);
1110 static void get_ctx(struct perf_event_context *ctx)
1112 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1115 static void free_ctx(struct rcu_head *head)
1117 struct perf_event_context *ctx;
1119 ctx = container_of(head, struct perf_event_context, rcu_head);
1120 kfree(ctx->task_ctx_data);
1124 static void put_ctx(struct perf_event_context *ctx)
1126 if (atomic_dec_and_test(&ctx->refcount)) {
1127 if (ctx->parent_ctx)
1128 put_ctx(ctx->parent_ctx);
1129 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1130 put_task_struct(ctx->task);
1131 call_rcu(&ctx->rcu_head, free_ctx);
1136 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1137 * perf_pmu_migrate_context() we need some magic.
1139 * Those places that change perf_event::ctx will hold both
1140 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1142 * Lock ordering is by mutex address. There are two other sites where
1143 * perf_event_context::mutex nests and those are:
1145 * - perf_event_exit_task_context() [ child , 0 ]
1146 * perf_event_exit_event()
1147 * put_event() [ parent, 1 ]
1149 * - perf_event_init_context() [ parent, 0 ]
1150 * inherit_task_group()
1153 * perf_event_alloc()
1155 * perf_try_init_event() [ child , 1 ]
1157 * While it appears there is an obvious deadlock here -- the parent and child
1158 * nesting levels are inverted between the two. This is in fact safe because
1159 * life-time rules separate them. That is an exiting task cannot fork, and a
1160 * spawning task cannot (yet) exit.
1162 * But remember that that these are parent<->child context relations, and
1163 * migration does not affect children, therefore these two orderings should not
1166 * The change in perf_event::ctx does not affect children (as claimed above)
1167 * because the sys_perf_event_open() case will install a new event and break
1168 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1169 * concerned with cpuctx and that doesn't have children.
1171 * The places that change perf_event::ctx will issue:
1173 * perf_remove_from_context();
1174 * synchronize_rcu();
1175 * perf_install_in_context();
1177 * to affect the change. The remove_from_context() + synchronize_rcu() should
1178 * quiesce the event, after which we can install it in the new location. This
1179 * means that only external vectors (perf_fops, prctl) can perturb the event
1180 * while in transit. Therefore all such accessors should also acquire
1181 * perf_event_context::mutex to serialize against this.
1183 * However; because event->ctx can change while we're waiting to acquire
1184 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1189 * task_struct::perf_event_mutex
1190 * perf_event_context::mutex
1191 * perf_event::child_mutex;
1192 * perf_event_context::lock
1193 * perf_event::mmap_mutex
1196 static struct perf_event_context *
1197 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1199 struct perf_event_context *ctx;
1203 ctx = ACCESS_ONCE(event->ctx);
1204 if (!atomic_inc_not_zero(&ctx->refcount)) {
1210 mutex_lock_nested(&ctx->mutex, nesting);
1211 if (event->ctx != ctx) {
1212 mutex_unlock(&ctx->mutex);
1220 static inline struct perf_event_context *
1221 perf_event_ctx_lock(struct perf_event *event)
1223 return perf_event_ctx_lock_nested(event, 0);
1226 static void perf_event_ctx_unlock(struct perf_event *event,
1227 struct perf_event_context *ctx)
1229 mutex_unlock(&ctx->mutex);
1234 * This must be done under the ctx->lock, such as to serialize against
1235 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1236 * calling scheduler related locks and ctx->lock nests inside those.
1238 static __must_check struct perf_event_context *
1239 unclone_ctx(struct perf_event_context *ctx)
1241 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1243 lockdep_assert_held(&ctx->lock);
1246 ctx->parent_ctx = NULL;
1252 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1255 * only top level events have the pid namespace they were created in
1258 event = event->parent;
1260 return task_tgid_nr_ns(p, event->ns);
1263 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1266 * only top level events have the pid namespace they were created in
1269 event = event->parent;
1271 return task_pid_nr_ns(p, event->ns);
1275 * If we inherit events we want to return the parent event id
1278 static u64 primary_event_id(struct perf_event *event)
1283 id = event->parent->id;
1289 * Get the perf_event_context for a task and lock it.
1291 * This has to cope with with the fact that until it is locked,
1292 * the context could get moved to another task.
1294 static struct perf_event_context *
1295 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1297 struct perf_event_context *ctx;
1301 * One of the few rules of preemptible RCU is that one cannot do
1302 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1303 * part of the read side critical section was irqs-enabled -- see
1304 * rcu_read_unlock_special().
1306 * Since ctx->lock nests under rq->lock we must ensure the entire read
1307 * side critical section has interrupts disabled.
1309 local_irq_save(*flags);
1311 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1314 * If this context is a clone of another, it might
1315 * get swapped for another underneath us by
1316 * perf_event_task_sched_out, though the
1317 * rcu_read_lock() protects us from any context
1318 * getting freed. Lock the context and check if it
1319 * got swapped before we could get the lock, and retry
1320 * if so. If we locked the right context, then it
1321 * can't get swapped on us any more.
1323 raw_spin_lock(&ctx->lock);
1324 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1325 raw_spin_unlock(&ctx->lock);
1327 local_irq_restore(*flags);
1331 if (ctx->task == TASK_TOMBSTONE ||
1332 !atomic_inc_not_zero(&ctx->refcount)) {
1333 raw_spin_unlock(&ctx->lock);
1336 WARN_ON_ONCE(ctx->task != task);
1341 local_irq_restore(*flags);
1346 * Get the context for a task and increment its pin_count so it
1347 * can't get swapped to another task. This also increments its
1348 * reference count so that the context can't get freed.
1350 static struct perf_event_context *
1351 perf_pin_task_context(struct task_struct *task, int ctxn)
1353 struct perf_event_context *ctx;
1354 unsigned long flags;
1356 ctx = perf_lock_task_context(task, ctxn, &flags);
1359 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1364 static void perf_unpin_context(struct perf_event_context *ctx)
1366 unsigned long flags;
1368 raw_spin_lock_irqsave(&ctx->lock, flags);
1370 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1374 * Update the record of the current time in a context.
1376 static void update_context_time(struct perf_event_context *ctx)
1378 u64 now = perf_clock();
1380 ctx->time += now - ctx->timestamp;
1381 ctx->timestamp = now;
1384 static u64 perf_event_time(struct perf_event *event)
1386 struct perf_event_context *ctx = event->ctx;
1388 if (is_cgroup_event(event))
1389 return perf_cgroup_event_time(event);
1391 return ctx ? ctx->time : 0;
1395 * Update the total_time_enabled and total_time_running fields for a event.
1397 static void update_event_times(struct perf_event *event)
1399 struct perf_event_context *ctx = event->ctx;
1402 lockdep_assert_held(&ctx->lock);
1404 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1405 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1409 * in cgroup mode, time_enabled represents
1410 * the time the event was enabled AND active
1411 * tasks were in the monitored cgroup. This is
1412 * independent of the activity of the context as
1413 * there may be a mix of cgroup and non-cgroup events.
1415 * That is why we treat cgroup events differently
1418 if (is_cgroup_event(event))
1419 run_end = perf_cgroup_event_time(event);
1420 else if (ctx->is_active)
1421 run_end = ctx->time;
1423 run_end = event->tstamp_stopped;
1425 event->total_time_enabled = run_end - event->tstamp_enabled;
1427 if (event->state == PERF_EVENT_STATE_INACTIVE)
1428 run_end = event->tstamp_stopped;
1430 run_end = perf_event_time(event);
1432 event->total_time_running = run_end - event->tstamp_running;
1437 * Update total_time_enabled and total_time_running for all events in a group.
1439 static void update_group_times(struct perf_event *leader)
1441 struct perf_event *event;
1443 update_event_times(leader);
1444 list_for_each_entry(event, &leader->sibling_list, group_entry)
1445 update_event_times(event);
1448 static enum event_type_t get_event_type(struct perf_event *event)
1450 struct perf_event_context *ctx = event->ctx;
1451 enum event_type_t event_type;
1453 lockdep_assert_held(&ctx->lock);
1455 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1457 event_type |= EVENT_CPU;
1462 static struct list_head *
1463 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1465 if (event->attr.pinned)
1466 return &ctx->pinned_groups;
1468 return &ctx->flexible_groups;
1472 * Add a event from the lists for its context.
1473 * Must be called with ctx->mutex and ctx->lock held.
1476 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1478 lockdep_assert_held(&ctx->lock);
1480 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1481 event->attach_state |= PERF_ATTACH_CONTEXT;
1484 * If we're a stand alone event or group leader, we go to the context
1485 * list, group events are kept attached to the group so that
1486 * perf_group_detach can, at all times, locate all siblings.
1488 if (event->group_leader == event) {
1489 struct list_head *list;
1491 event->group_caps = event->event_caps;
1493 list = ctx_group_list(event, ctx);
1494 list_add_tail(&event->group_entry, list);
1497 list_update_cgroup_event(event, ctx, true);
1499 list_add_rcu(&event->event_entry, &ctx->event_list);
1501 if (event->attr.inherit_stat)
1508 * Initialize event state based on the perf_event_attr::disabled.
1510 static inline void perf_event__state_init(struct perf_event *event)
1512 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1513 PERF_EVENT_STATE_INACTIVE;
1516 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1518 int entry = sizeof(u64); /* value */
1522 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1523 size += sizeof(u64);
1525 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1526 size += sizeof(u64);
1528 if (event->attr.read_format & PERF_FORMAT_ID)
1529 entry += sizeof(u64);
1531 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1533 size += sizeof(u64);
1537 event->read_size = size;
1540 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1542 struct perf_sample_data *data;
1545 if (sample_type & PERF_SAMPLE_IP)
1546 size += sizeof(data->ip);
1548 if (sample_type & PERF_SAMPLE_ADDR)
1549 size += sizeof(data->addr);
1551 if (sample_type & PERF_SAMPLE_PERIOD)
1552 size += sizeof(data->period);
1554 if (sample_type & PERF_SAMPLE_WEIGHT)
1555 size += sizeof(data->weight);
1557 if (sample_type & PERF_SAMPLE_READ)
1558 size += event->read_size;
1560 if (sample_type & PERF_SAMPLE_DATA_SRC)
1561 size += sizeof(data->data_src.val);
1563 if (sample_type & PERF_SAMPLE_TRANSACTION)
1564 size += sizeof(data->txn);
1566 event->header_size = size;
1570 * Called at perf_event creation and when events are attached/detached from a
1573 static void perf_event__header_size(struct perf_event *event)
1575 __perf_event_read_size(event,
1576 event->group_leader->nr_siblings);
1577 __perf_event_header_size(event, event->attr.sample_type);
1580 static void perf_event__id_header_size(struct perf_event *event)
1582 struct perf_sample_data *data;
1583 u64 sample_type = event->attr.sample_type;
1586 if (sample_type & PERF_SAMPLE_TID)
1587 size += sizeof(data->tid_entry);
1589 if (sample_type & PERF_SAMPLE_TIME)
1590 size += sizeof(data->time);
1592 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1593 size += sizeof(data->id);
1595 if (sample_type & PERF_SAMPLE_ID)
1596 size += sizeof(data->id);
1598 if (sample_type & PERF_SAMPLE_STREAM_ID)
1599 size += sizeof(data->stream_id);
1601 if (sample_type & PERF_SAMPLE_CPU)
1602 size += sizeof(data->cpu_entry);
1604 event->id_header_size = size;
1607 static bool perf_event_validate_size(struct perf_event *event)
1610 * The values computed here will be over-written when we actually
1613 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1614 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1615 perf_event__id_header_size(event);
1618 * Sum the lot; should not exceed the 64k limit we have on records.
1619 * Conservative limit to allow for callchains and other variable fields.
1621 if (event->read_size + event->header_size +
1622 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1628 static void perf_group_attach(struct perf_event *event)
1630 struct perf_event *group_leader = event->group_leader, *pos;
1632 lockdep_assert_held(&event->ctx->lock);
1635 * We can have double attach due to group movement in perf_event_open.
1637 if (event->attach_state & PERF_ATTACH_GROUP)
1640 event->attach_state |= PERF_ATTACH_GROUP;
1642 if (group_leader == event)
1645 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1647 group_leader->group_caps &= event->event_caps;
1649 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1650 group_leader->nr_siblings++;
1652 perf_event__header_size(group_leader);
1654 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1655 perf_event__header_size(pos);
1659 * Remove a event from the lists for its context.
1660 * Must be called with ctx->mutex and ctx->lock held.
1663 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1665 WARN_ON_ONCE(event->ctx != ctx);
1666 lockdep_assert_held(&ctx->lock);
1669 * We can have double detach due to exit/hot-unplug + close.
1671 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1674 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1676 list_update_cgroup_event(event, ctx, false);
1679 if (event->attr.inherit_stat)
1682 list_del_rcu(&event->event_entry);
1684 if (event->group_leader == event)
1685 list_del_init(&event->group_entry);
1687 update_group_times(event);
1690 * If event was in error state, then keep it
1691 * that way, otherwise bogus counts will be
1692 * returned on read(). The only way to get out
1693 * of error state is by explicit re-enabling
1696 if (event->state > PERF_EVENT_STATE_OFF)
1697 event->state = PERF_EVENT_STATE_OFF;
1702 static void perf_group_detach(struct perf_event *event)
1704 struct perf_event *sibling, *tmp;
1705 struct list_head *list = NULL;
1707 lockdep_assert_held(&event->ctx->lock);
1710 * We can have double detach due to exit/hot-unplug + close.
1712 if (!(event->attach_state & PERF_ATTACH_GROUP))
1715 event->attach_state &= ~PERF_ATTACH_GROUP;
1718 * If this is a sibling, remove it from its group.
1720 if (event->group_leader != event) {
1721 list_del_init(&event->group_entry);
1722 event->group_leader->nr_siblings--;
1726 if (!list_empty(&event->group_entry))
1727 list = &event->group_entry;
1730 * If this was a group event with sibling events then
1731 * upgrade the siblings to singleton events by adding them
1732 * to whatever list we are on.
1734 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1736 list_move_tail(&sibling->group_entry, list);
1737 sibling->group_leader = sibling;
1739 /* Inherit group flags from the previous leader */
1740 sibling->group_caps = event->group_caps;
1742 WARN_ON_ONCE(sibling->ctx != event->ctx);
1746 perf_event__header_size(event->group_leader);
1748 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1749 perf_event__header_size(tmp);
1752 static bool is_orphaned_event(struct perf_event *event)
1754 return event->state == PERF_EVENT_STATE_DEAD;
1757 static inline int __pmu_filter_match(struct perf_event *event)
1759 struct pmu *pmu = event->pmu;
1760 return pmu->filter_match ? pmu->filter_match(event) : 1;
1764 * Check whether we should attempt to schedule an event group based on
1765 * PMU-specific filtering. An event group can consist of HW and SW events,
1766 * potentially with a SW leader, so we must check all the filters, to
1767 * determine whether a group is schedulable:
1769 static inline int pmu_filter_match(struct perf_event *event)
1771 struct perf_event *child;
1773 if (!__pmu_filter_match(event))
1776 list_for_each_entry(child, &event->sibling_list, group_entry) {
1777 if (!__pmu_filter_match(child))
1785 event_filter_match(struct perf_event *event)
1787 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1788 perf_cgroup_match(event) && pmu_filter_match(event);
1792 event_sched_out(struct perf_event *event,
1793 struct perf_cpu_context *cpuctx,
1794 struct perf_event_context *ctx)
1796 u64 tstamp = perf_event_time(event);
1799 WARN_ON_ONCE(event->ctx != ctx);
1800 lockdep_assert_held(&ctx->lock);
1803 * An event which could not be activated because of
1804 * filter mismatch still needs to have its timings
1805 * maintained, otherwise bogus information is return
1806 * via read() for time_enabled, time_running:
1808 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1809 !event_filter_match(event)) {
1810 delta = tstamp - event->tstamp_stopped;
1811 event->tstamp_running += delta;
1812 event->tstamp_stopped = tstamp;
1815 if (event->state != PERF_EVENT_STATE_ACTIVE)
1818 perf_pmu_disable(event->pmu);
1820 event->tstamp_stopped = tstamp;
1821 event->pmu->del(event, 0);
1823 event->state = PERF_EVENT_STATE_INACTIVE;
1824 if (event->pending_disable) {
1825 event->pending_disable = 0;
1826 event->state = PERF_EVENT_STATE_OFF;
1829 if (!is_software_event(event))
1830 cpuctx->active_oncpu--;
1831 if (!--ctx->nr_active)
1832 perf_event_ctx_deactivate(ctx);
1833 if (event->attr.freq && event->attr.sample_freq)
1835 if (event->attr.exclusive || !cpuctx->active_oncpu)
1836 cpuctx->exclusive = 0;
1838 perf_pmu_enable(event->pmu);
1842 group_sched_out(struct perf_event *group_event,
1843 struct perf_cpu_context *cpuctx,
1844 struct perf_event_context *ctx)
1846 struct perf_event *event;
1847 int state = group_event->state;
1849 perf_pmu_disable(ctx->pmu);
1851 event_sched_out(group_event, cpuctx, ctx);
1854 * Schedule out siblings (if any):
1856 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1857 event_sched_out(event, cpuctx, ctx);
1859 perf_pmu_enable(ctx->pmu);
1861 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1862 cpuctx->exclusive = 0;
1865 #define DETACH_GROUP 0x01UL
1868 * Cross CPU call to remove a performance event
1870 * We disable the event on the hardware level first. After that we
1871 * remove it from the context list.
1874 __perf_remove_from_context(struct perf_event *event,
1875 struct perf_cpu_context *cpuctx,
1876 struct perf_event_context *ctx,
1879 unsigned long flags = (unsigned long)info;
1881 event_sched_out(event, cpuctx, ctx);
1882 if (flags & DETACH_GROUP)
1883 perf_group_detach(event);
1884 list_del_event(event, ctx);
1886 if (!ctx->nr_events && ctx->is_active) {
1889 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1890 cpuctx->task_ctx = NULL;
1896 * Remove the event from a task's (or a CPU's) list of events.
1898 * If event->ctx is a cloned context, callers must make sure that
1899 * every task struct that event->ctx->task could possibly point to
1900 * remains valid. This is OK when called from perf_release since
1901 * that only calls us on the top-level context, which can't be a clone.
1902 * When called from perf_event_exit_task, it's OK because the
1903 * context has been detached from its task.
1905 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1907 struct perf_event_context *ctx = event->ctx;
1909 lockdep_assert_held(&ctx->mutex);
1911 event_function_call(event, __perf_remove_from_context, (void *)flags);
1914 * The above event_function_call() can NO-OP when it hits
1915 * TASK_TOMBSTONE. In that case we must already have been detached
1916 * from the context (by perf_event_exit_event()) but the grouping
1917 * might still be in-tact.
1919 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1920 if ((flags & DETACH_GROUP) &&
1921 (event->attach_state & PERF_ATTACH_GROUP)) {
1923 * Since in that case we cannot possibly be scheduled, simply
1926 raw_spin_lock_irq(&ctx->lock);
1927 perf_group_detach(event);
1928 raw_spin_unlock_irq(&ctx->lock);
1933 * Cross CPU call to disable a performance event
1935 static void __perf_event_disable(struct perf_event *event,
1936 struct perf_cpu_context *cpuctx,
1937 struct perf_event_context *ctx,
1940 if (event->state < PERF_EVENT_STATE_INACTIVE)
1943 update_context_time(ctx);
1944 update_cgrp_time_from_event(event);
1945 update_group_times(event);
1946 if (event == event->group_leader)
1947 group_sched_out(event, cpuctx, ctx);
1949 event_sched_out(event, cpuctx, ctx);
1950 event->state = PERF_EVENT_STATE_OFF;
1956 * If event->ctx is a cloned context, callers must make sure that
1957 * every task struct that event->ctx->task could possibly point to
1958 * remains valid. This condition is satisifed when called through
1959 * perf_event_for_each_child or perf_event_for_each because they
1960 * hold the top-level event's child_mutex, so any descendant that
1961 * goes to exit will block in perf_event_exit_event().
1963 * When called from perf_pending_event it's OK because event->ctx
1964 * is the current context on this CPU and preemption is disabled,
1965 * hence we can't get into perf_event_task_sched_out for this context.
1967 static void _perf_event_disable(struct perf_event *event)
1969 struct perf_event_context *ctx = event->ctx;
1971 raw_spin_lock_irq(&ctx->lock);
1972 if (event->state <= PERF_EVENT_STATE_OFF) {
1973 raw_spin_unlock_irq(&ctx->lock);
1976 raw_spin_unlock_irq(&ctx->lock);
1978 event_function_call(event, __perf_event_disable, NULL);
1981 void perf_event_disable_local(struct perf_event *event)
1983 event_function_local(event, __perf_event_disable, NULL);
1987 * Strictly speaking kernel users cannot create groups and therefore this
1988 * interface does not need the perf_event_ctx_lock() magic.
1990 void perf_event_disable(struct perf_event *event)
1992 struct perf_event_context *ctx;
1994 ctx = perf_event_ctx_lock(event);
1995 _perf_event_disable(event);
1996 perf_event_ctx_unlock(event, ctx);
1998 EXPORT_SYMBOL_GPL(perf_event_disable);
2000 void perf_event_disable_inatomic(struct perf_event *event)
2002 event->pending_disable = 1;
2003 irq_work_queue(&event->pending);
2006 static void perf_set_shadow_time(struct perf_event *event,
2007 struct perf_event_context *ctx,
2011 * use the correct time source for the time snapshot
2013 * We could get by without this by leveraging the
2014 * fact that to get to this function, the caller
2015 * has most likely already called update_context_time()
2016 * and update_cgrp_time_xx() and thus both timestamp
2017 * are identical (or very close). Given that tstamp is,
2018 * already adjusted for cgroup, we could say that:
2019 * tstamp - ctx->timestamp
2021 * tstamp - cgrp->timestamp.
2023 * Then, in perf_output_read(), the calculation would
2024 * work with no changes because:
2025 * - event is guaranteed scheduled in
2026 * - no scheduled out in between
2027 * - thus the timestamp would be the same
2029 * But this is a bit hairy.
2031 * So instead, we have an explicit cgroup call to remain
2032 * within the time time source all along. We believe it
2033 * is cleaner and simpler to understand.
2035 if (is_cgroup_event(event))
2036 perf_cgroup_set_shadow_time(event, tstamp);
2038 event->shadow_ctx_time = tstamp - ctx->timestamp;
2041 #define MAX_INTERRUPTS (~0ULL)
2043 static void perf_log_throttle(struct perf_event *event, int enable);
2044 static void perf_log_itrace_start(struct perf_event *event);
2047 event_sched_in(struct perf_event *event,
2048 struct perf_cpu_context *cpuctx,
2049 struct perf_event_context *ctx)
2051 u64 tstamp = perf_event_time(event);
2054 lockdep_assert_held(&ctx->lock);
2056 if (event->state <= PERF_EVENT_STATE_OFF)
2059 WRITE_ONCE(event->oncpu, smp_processor_id());
2061 * Order event::oncpu write to happen before the ACTIVE state
2065 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2068 * Unthrottle events, since we scheduled we might have missed several
2069 * ticks already, also for a heavily scheduling task there is little
2070 * guarantee it'll get a tick in a timely manner.
2072 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2073 perf_log_throttle(event, 1);
2074 event->hw.interrupts = 0;
2078 * The new state must be visible before we turn it on in the hardware:
2082 perf_pmu_disable(event->pmu);
2084 perf_set_shadow_time(event, ctx, tstamp);
2086 perf_log_itrace_start(event);
2088 if (event->pmu->add(event, PERF_EF_START)) {
2089 event->state = PERF_EVENT_STATE_INACTIVE;
2095 event->tstamp_running += tstamp - event->tstamp_stopped;
2097 if (!is_software_event(event))
2098 cpuctx->active_oncpu++;
2099 if (!ctx->nr_active++)
2100 perf_event_ctx_activate(ctx);
2101 if (event->attr.freq && event->attr.sample_freq)
2104 if (event->attr.exclusive)
2105 cpuctx->exclusive = 1;
2108 perf_pmu_enable(event->pmu);
2114 group_sched_in(struct perf_event *group_event,
2115 struct perf_cpu_context *cpuctx,
2116 struct perf_event_context *ctx)
2118 struct perf_event *event, *partial_group = NULL;
2119 struct pmu *pmu = ctx->pmu;
2120 u64 now = ctx->time;
2121 bool simulate = false;
2123 if (group_event->state == PERF_EVENT_STATE_OFF)
2126 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2128 if (event_sched_in(group_event, cpuctx, ctx)) {
2129 pmu->cancel_txn(pmu);
2130 perf_mux_hrtimer_restart(cpuctx);
2135 * Schedule in siblings as one group (if any):
2137 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2138 if (event_sched_in(event, cpuctx, ctx)) {
2139 partial_group = event;
2144 if (!pmu->commit_txn(pmu))
2149 * Groups can be scheduled in as one unit only, so undo any
2150 * partial group before returning:
2151 * The events up to the failed event are scheduled out normally,
2152 * tstamp_stopped will be updated.
2154 * The failed events and the remaining siblings need to have
2155 * their timings updated as if they had gone thru event_sched_in()
2156 * and event_sched_out(). This is required to get consistent timings
2157 * across the group. This also takes care of the case where the group
2158 * could never be scheduled by ensuring tstamp_stopped is set to mark
2159 * the time the event was actually stopped, such that time delta
2160 * calculation in update_event_times() is correct.
2162 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2163 if (event == partial_group)
2167 event->tstamp_running += now - event->tstamp_stopped;
2168 event->tstamp_stopped = now;
2170 event_sched_out(event, cpuctx, ctx);
2173 event_sched_out(group_event, cpuctx, ctx);
2175 pmu->cancel_txn(pmu);
2177 perf_mux_hrtimer_restart(cpuctx);
2183 * Work out whether we can put this event group on the CPU now.
2185 static int group_can_go_on(struct perf_event *event,
2186 struct perf_cpu_context *cpuctx,
2190 * Groups consisting entirely of software events can always go on.
2192 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2195 * If an exclusive group is already on, no other hardware
2198 if (cpuctx->exclusive)
2201 * If this group is exclusive and there are already
2202 * events on the CPU, it can't go on.
2204 if (event->attr.exclusive && cpuctx->active_oncpu)
2207 * Otherwise, try to add it if all previous groups were able
2213 static void add_event_to_ctx(struct perf_event *event,
2214 struct perf_event_context *ctx)
2216 u64 tstamp = perf_event_time(event);
2218 list_add_event(event, ctx);
2219 perf_group_attach(event);
2220 event->tstamp_enabled = tstamp;
2221 event->tstamp_running = tstamp;
2222 event->tstamp_stopped = tstamp;
2225 static void ctx_sched_out(struct perf_event_context *ctx,
2226 struct perf_cpu_context *cpuctx,
2227 enum event_type_t event_type);
2229 ctx_sched_in(struct perf_event_context *ctx,
2230 struct perf_cpu_context *cpuctx,
2231 enum event_type_t event_type,
2232 struct task_struct *task);
2234 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2235 struct perf_event_context *ctx,
2236 enum event_type_t event_type)
2238 if (!cpuctx->task_ctx)
2241 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2244 ctx_sched_out(ctx, cpuctx, event_type);
2247 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2248 struct perf_event_context *ctx,
2249 struct task_struct *task)
2251 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2253 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2254 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2256 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2260 * We want to maintain the following priority of scheduling:
2261 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2262 * - task pinned (EVENT_PINNED)
2263 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2264 * - task flexible (EVENT_FLEXIBLE).
2266 * In order to avoid unscheduling and scheduling back in everything every
2267 * time an event is added, only do it for the groups of equal priority and
2270 * This can be called after a batch operation on task events, in which case
2271 * event_type is a bit mask of the types of events involved. For CPU events,
2272 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2274 static void ctx_resched(struct perf_cpu_context *cpuctx,
2275 struct perf_event_context *task_ctx,
2276 enum event_type_t event_type)
2278 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2279 bool cpu_event = !!(event_type & EVENT_CPU);
2282 * If pinned groups are involved, flexible groups also need to be
2285 if (event_type & EVENT_PINNED)
2286 event_type |= EVENT_FLEXIBLE;
2288 perf_pmu_disable(cpuctx->ctx.pmu);
2290 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2293 * Decide which cpu ctx groups to schedule out based on the types
2294 * of events that caused rescheduling:
2295 * - EVENT_CPU: schedule out corresponding groups;
2296 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2297 * - otherwise, do nothing more.
2300 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2301 else if (ctx_event_type & EVENT_PINNED)
2302 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2304 perf_event_sched_in(cpuctx, task_ctx, current);
2305 perf_pmu_enable(cpuctx->ctx.pmu);
2309 * Cross CPU call to install and enable a performance event
2311 * Very similar to remote_function() + event_function() but cannot assume that
2312 * things like ctx->is_active and cpuctx->task_ctx are set.
2314 static int __perf_install_in_context(void *info)
2316 struct perf_event *event = info;
2317 struct perf_event_context *ctx = event->ctx;
2318 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2319 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2320 bool reprogram = true;
2323 raw_spin_lock(&cpuctx->ctx.lock);
2325 raw_spin_lock(&ctx->lock);
2328 reprogram = (ctx->task == current);
2331 * If the task is running, it must be running on this CPU,
2332 * otherwise we cannot reprogram things.
2334 * If its not running, we don't care, ctx->lock will
2335 * serialize against it becoming runnable.
2337 if (task_curr(ctx->task) && !reprogram) {
2342 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2343 } else if (task_ctx) {
2344 raw_spin_lock(&task_ctx->lock);
2348 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2349 add_event_to_ctx(event, ctx);
2350 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2352 add_event_to_ctx(event, ctx);
2356 perf_ctx_unlock(cpuctx, task_ctx);
2362 * Attach a performance event to a context.
2364 * Very similar to event_function_call, see comment there.
2367 perf_install_in_context(struct perf_event_context *ctx,
2368 struct perf_event *event,
2371 struct task_struct *task = READ_ONCE(ctx->task);
2373 lockdep_assert_held(&ctx->mutex);
2375 if (event->cpu != -1)
2379 * Ensures that if we can observe event->ctx, both the event and ctx
2380 * will be 'complete'. See perf_iterate_sb_cpu().
2382 smp_store_release(&event->ctx, ctx);
2385 cpu_function_call(cpu, __perf_install_in_context, event);
2390 * Should not happen, we validate the ctx is still alive before calling.
2392 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2396 * Installing events is tricky because we cannot rely on ctx->is_active
2397 * to be set in case this is the nr_events 0 -> 1 transition.
2399 * Instead we use task_curr(), which tells us if the task is running.
2400 * However, since we use task_curr() outside of rq::lock, we can race
2401 * against the actual state. This means the result can be wrong.
2403 * If we get a false positive, we retry, this is harmless.
2405 * If we get a false negative, things are complicated. If we are after
2406 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2407 * value must be correct. If we're before, it doesn't matter since
2408 * perf_event_context_sched_in() will program the counter.
2410 * However, this hinges on the remote context switch having observed
2411 * our task->perf_event_ctxp[] store, such that it will in fact take
2412 * ctx::lock in perf_event_context_sched_in().
2414 * We do this by task_function_call(), if the IPI fails to hit the task
2415 * we know any future context switch of task must see the
2416 * perf_event_ctpx[] store.
2420 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2421 * task_cpu() load, such that if the IPI then does not find the task
2422 * running, a future context switch of that task must observe the
2427 if (!task_function_call(task, __perf_install_in_context, event))
2430 raw_spin_lock_irq(&ctx->lock);
2432 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2434 * Cannot happen because we already checked above (which also
2435 * cannot happen), and we hold ctx->mutex, which serializes us
2436 * against perf_event_exit_task_context().
2438 raw_spin_unlock_irq(&ctx->lock);
2442 * If the task is not running, ctx->lock will avoid it becoming so,
2443 * thus we can safely install the event.
2445 if (task_curr(task)) {
2446 raw_spin_unlock_irq(&ctx->lock);
2449 add_event_to_ctx(event, ctx);
2450 raw_spin_unlock_irq(&ctx->lock);
2454 * Put a event into inactive state and update time fields.
2455 * Enabling the leader of a group effectively enables all
2456 * the group members that aren't explicitly disabled, so we
2457 * have to update their ->tstamp_enabled also.
2458 * Note: this works for group members as well as group leaders
2459 * since the non-leader members' sibling_lists will be empty.
2461 static void __perf_event_mark_enabled(struct perf_event *event)
2463 struct perf_event *sub;
2464 u64 tstamp = perf_event_time(event);
2466 event->state = PERF_EVENT_STATE_INACTIVE;
2467 event->tstamp_enabled = tstamp - event->total_time_enabled;
2468 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2469 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2470 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2475 * Cross CPU call to enable a performance event
2477 static void __perf_event_enable(struct perf_event *event,
2478 struct perf_cpu_context *cpuctx,
2479 struct perf_event_context *ctx,
2482 struct perf_event *leader = event->group_leader;
2483 struct perf_event_context *task_ctx;
2485 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2486 event->state <= PERF_EVENT_STATE_ERROR)
2490 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2492 __perf_event_mark_enabled(event);
2494 if (!ctx->is_active)
2497 if (!event_filter_match(event)) {
2498 if (is_cgroup_event(event))
2499 perf_cgroup_defer_enabled(event);
2500 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2505 * If the event is in a group and isn't the group leader,
2506 * then don't put it on unless the group is on.
2508 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2509 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2513 task_ctx = cpuctx->task_ctx;
2515 WARN_ON_ONCE(task_ctx != ctx);
2517 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2523 * If event->ctx is a cloned context, callers must make sure that
2524 * every task struct that event->ctx->task could possibly point to
2525 * remains valid. This condition is satisfied when called through
2526 * perf_event_for_each_child or perf_event_for_each as described
2527 * for perf_event_disable.
2529 static void _perf_event_enable(struct perf_event *event)
2531 struct perf_event_context *ctx = event->ctx;
2533 raw_spin_lock_irq(&ctx->lock);
2534 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2535 event->state < PERF_EVENT_STATE_ERROR) {
2536 raw_spin_unlock_irq(&ctx->lock);
2541 * If the event is in error state, clear that first.
2543 * That way, if we see the event in error state below, we know that it
2544 * has gone back into error state, as distinct from the task having
2545 * been scheduled away before the cross-call arrived.
2547 if (event->state == PERF_EVENT_STATE_ERROR)
2548 event->state = PERF_EVENT_STATE_OFF;
2549 raw_spin_unlock_irq(&ctx->lock);
2551 event_function_call(event, __perf_event_enable, NULL);
2555 * See perf_event_disable();
2557 void perf_event_enable(struct perf_event *event)
2559 struct perf_event_context *ctx;
2561 ctx = perf_event_ctx_lock(event);
2562 _perf_event_enable(event);
2563 perf_event_ctx_unlock(event, ctx);
2565 EXPORT_SYMBOL_GPL(perf_event_enable);
2567 struct stop_event_data {
2568 struct perf_event *event;
2569 unsigned int restart;
2572 static int __perf_event_stop(void *info)
2574 struct stop_event_data *sd = info;
2575 struct perf_event *event = sd->event;
2577 /* if it's already INACTIVE, do nothing */
2578 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2581 /* matches smp_wmb() in event_sched_in() */
2585 * There is a window with interrupts enabled before we get here,
2586 * so we need to check again lest we try to stop another CPU's event.
2588 if (READ_ONCE(event->oncpu) != smp_processor_id())
2591 event->pmu->stop(event, PERF_EF_UPDATE);
2594 * May race with the actual stop (through perf_pmu_output_stop()),
2595 * but it is only used for events with AUX ring buffer, and such
2596 * events will refuse to restart because of rb::aux_mmap_count==0,
2597 * see comments in perf_aux_output_begin().
2599 * Since this is happening on a event-local CPU, no trace is lost
2603 event->pmu->start(event, 0);
2608 static int perf_event_stop(struct perf_event *event, int restart)
2610 struct stop_event_data sd = {
2617 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2620 /* matches smp_wmb() in event_sched_in() */
2624 * We only want to restart ACTIVE events, so if the event goes
2625 * inactive here (event->oncpu==-1), there's nothing more to do;
2626 * fall through with ret==-ENXIO.
2628 ret = cpu_function_call(READ_ONCE(event->oncpu),
2629 __perf_event_stop, &sd);
2630 } while (ret == -EAGAIN);
2636 * In order to contain the amount of racy and tricky in the address filter
2637 * configuration management, it is a two part process:
2639 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2640 * we update the addresses of corresponding vmas in
2641 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2642 * (p2) when an event is scheduled in (pmu::add), it calls
2643 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2644 * if the generation has changed since the previous call.
2646 * If (p1) happens while the event is active, we restart it to force (p2).
2648 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2649 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2651 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2652 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2654 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2657 void perf_event_addr_filters_sync(struct perf_event *event)
2659 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2661 if (!has_addr_filter(event))
2664 raw_spin_lock(&ifh->lock);
2665 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2666 event->pmu->addr_filters_sync(event);
2667 event->hw.addr_filters_gen = event->addr_filters_gen;
2669 raw_spin_unlock(&ifh->lock);
2671 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2673 static int _perf_event_refresh(struct perf_event *event, int refresh)
2676 * not supported on inherited events
2678 if (event->attr.inherit || !is_sampling_event(event))
2681 atomic_add(refresh, &event->event_limit);
2682 _perf_event_enable(event);
2688 * See perf_event_disable()
2690 int perf_event_refresh(struct perf_event *event, int refresh)
2692 struct perf_event_context *ctx;
2695 ctx = perf_event_ctx_lock(event);
2696 ret = _perf_event_refresh(event, refresh);
2697 perf_event_ctx_unlock(event, ctx);
2701 EXPORT_SYMBOL_GPL(perf_event_refresh);
2703 static void ctx_sched_out(struct perf_event_context *ctx,
2704 struct perf_cpu_context *cpuctx,
2705 enum event_type_t event_type)
2707 int is_active = ctx->is_active;
2708 struct perf_event *event;
2710 lockdep_assert_held(&ctx->lock);
2712 if (likely(!ctx->nr_events)) {
2714 * See __perf_remove_from_context().
2716 WARN_ON_ONCE(ctx->is_active);
2718 WARN_ON_ONCE(cpuctx->task_ctx);
2722 ctx->is_active &= ~event_type;
2723 if (!(ctx->is_active & EVENT_ALL))
2727 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2728 if (!ctx->is_active)
2729 cpuctx->task_ctx = NULL;
2733 * Always update time if it was set; not only when it changes.
2734 * Otherwise we can 'forget' to update time for any but the last
2735 * context we sched out. For example:
2737 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2738 * ctx_sched_out(.event_type = EVENT_PINNED)
2740 * would only update time for the pinned events.
2742 if (is_active & EVENT_TIME) {
2743 /* update (and stop) ctx time */
2744 update_context_time(ctx);
2745 update_cgrp_time_from_cpuctx(cpuctx);
2748 is_active ^= ctx->is_active; /* changed bits */
2750 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2753 perf_pmu_disable(ctx->pmu);
2754 if (is_active & EVENT_PINNED) {
2755 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2756 group_sched_out(event, cpuctx, ctx);
2759 if (is_active & EVENT_FLEXIBLE) {
2760 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2761 group_sched_out(event, cpuctx, ctx);
2763 perf_pmu_enable(ctx->pmu);
2767 * Test whether two contexts are equivalent, i.e. whether they have both been
2768 * cloned from the same version of the same context.
2770 * Equivalence is measured using a generation number in the context that is
2771 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2772 * and list_del_event().
2774 static int context_equiv(struct perf_event_context *ctx1,
2775 struct perf_event_context *ctx2)
2777 lockdep_assert_held(&ctx1->lock);
2778 lockdep_assert_held(&ctx2->lock);
2780 /* Pinning disables the swap optimization */
2781 if (ctx1->pin_count || ctx2->pin_count)
2784 /* If ctx1 is the parent of ctx2 */
2785 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2788 /* If ctx2 is the parent of ctx1 */
2789 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2793 * If ctx1 and ctx2 have the same parent; we flatten the parent
2794 * hierarchy, see perf_event_init_context().
2796 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2797 ctx1->parent_gen == ctx2->parent_gen)
2804 static void __perf_event_sync_stat(struct perf_event *event,
2805 struct perf_event *next_event)
2809 if (!event->attr.inherit_stat)
2813 * Update the event value, we cannot use perf_event_read()
2814 * because we're in the middle of a context switch and have IRQs
2815 * disabled, which upsets smp_call_function_single(), however
2816 * we know the event must be on the current CPU, therefore we
2817 * don't need to use it.
2819 switch (event->state) {
2820 case PERF_EVENT_STATE_ACTIVE:
2821 event->pmu->read(event);
2824 case PERF_EVENT_STATE_INACTIVE:
2825 update_event_times(event);
2833 * In order to keep per-task stats reliable we need to flip the event
2834 * values when we flip the contexts.
2836 value = local64_read(&next_event->count);
2837 value = local64_xchg(&event->count, value);
2838 local64_set(&next_event->count, value);
2840 swap(event->total_time_enabled, next_event->total_time_enabled);
2841 swap(event->total_time_running, next_event->total_time_running);
2844 * Since we swizzled the values, update the user visible data too.
2846 perf_event_update_userpage(event);
2847 perf_event_update_userpage(next_event);
2850 static void perf_event_sync_stat(struct perf_event_context *ctx,
2851 struct perf_event_context *next_ctx)
2853 struct perf_event *event, *next_event;
2858 update_context_time(ctx);
2860 event = list_first_entry(&ctx->event_list,
2861 struct perf_event, event_entry);
2863 next_event = list_first_entry(&next_ctx->event_list,
2864 struct perf_event, event_entry);
2866 while (&event->event_entry != &ctx->event_list &&
2867 &next_event->event_entry != &next_ctx->event_list) {
2869 __perf_event_sync_stat(event, next_event);
2871 event = list_next_entry(event, event_entry);
2872 next_event = list_next_entry(next_event, event_entry);
2876 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2877 struct task_struct *next)
2879 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2880 struct perf_event_context *next_ctx;
2881 struct perf_event_context *parent, *next_parent;
2882 struct perf_cpu_context *cpuctx;
2888 cpuctx = __get_cpu_context(ctx);
2889 if (!cpuctx->task_ctx)
2893 next_ctx = next->perf_event_ctxp[ctxn];
2897 parent = rcu_dereference(ctx->parent_ctx);
2898 next_parent = rcu_dereference(next_ctx->parent_ctx);
2900 /* If neither context have a parent context; they cannot be clones. */
2901 if (!parent && !next_parent)
2904 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2906 * Looks like the two contexts are clones, so we might be
2907 * able to optimize the context switch. We lock both
2908 * contexts and check that they are clones under the
2909 * lock (including re-checking that neither has been
2910 * uncloned in the meantime). It doesn't matter which
2911 * order we take the locks because no other cpu could
2912 * be trying to lock both of these tasks.
2914 raw_spin_lock(&ctx->lock);
2915 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2916 if (context_equiv(ctx, next_ctx)) {
2917 WRITE_ONCE(ctx->task, next);
2918 WRITE_ONCE(next_ctx->task, task);
2920 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2923 * RCU_INIT_POINTER here is safe because we've not
2924 * modified the ctx and the above modification of
2925 * ctx->task and ctx->task_ctx_data are immaterial
2926 * since those values are always verified under
2927 * ctx->lock which we're now holding.
2929 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2930 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2934 perf_event_sync_stat(ctx, next_ctx);
2936 raw_spin_unlock(&next_ctx->lock);
2937 raw_spin_unlock(&ctx->lock);
2943 raw_spin_lock(&ctx->lock);
2944 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2945 raw_spin_unlock(&ctx->lock);
2949 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2951 void perf_sched_cb_dec(struct pmu *pmu)
2953 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2955 this_cpu_dec(perf_sched_cb_usages);
2957 if (!--cpuctx->sched_cb_usage)
2958 list_del(&cpuctx->sched_cb_entry);
2962 void perf_sched_cb_inc(struct pmu *pmu)
2964 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2966 if (!cpuctx->sched_cb_usage++)
2967 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2969 this_cpu_inc(perf_sched_cb_usages);
2973 * This function provides the context switch callback to the lower code
2974 * layer. It is invoked ONLY when the context switch callback is enabled.
2976 * This callback is relevant even to per-cpu events; for example multi event
2977 * PEBS requires this to provide PID/TID information. This requires we flush
2978 * all queued PEBS records before we context switch to a new task.
2980 static void perf_pmu_sched_task(struct task_struct *prev,
2981 struct task_struct *next,
2984 struct perf_cpu_context *cpuctx;
2990 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2991 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2993 if (WARN_ON_ONCE(!pmu->sched_task))
2996 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2997 perf_pmu_disable(pmu);
2999 pmu->sched_task(cpuctx->task_ctx, sched_in);
3001 perf_pmu_enable(pmu);
3002 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3006 static void perf_event_switch(struct task_struct *task,
3007 struct task_struct *next_prev, bool sched_in);
3009 #define for_each_task_context_nr(ctxn) \
3010 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3013 * Called from scheduler to remove the events of the current task,
3014 * with interrupts disabled.
3016 * We stop each event and update the event value in event->count.
3018 * This does not protect us against NMI, but disable()
3019 * sets the disabled bit in the control field of event _before_
3020 * accessing the event control register. If a NMI hits, then it will
3021 * not restart the event.
3023 void __perf_event_task_sched_out(struct task_struct *task,
3024 struct task_struct *next)
3028 if (__this_cpu_read(perf_sched_cb_usages))
3029 perf_pmu_sched_task(task, next, false);
3031 if (atomic_read(&nr_switch_events))
3032 perf_event_switch(task, next, false);
3034 for_each_task_context_nr(ctxn)
3035 perf_event_context_sched_out(task, ctxn, next);
3038 * if cgroup events exist on this CPU, then we need
3039 * to check if we have to switch out PMU state.
3040 * cgroup event are system-wide mode only
3042 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3043 perf_cgroup_sched_out(task, next);
3047 * Called with IRQs disabled
3049 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3050 enum event_type_t event_type)
3052 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3056 ctx_pinned_sched_in(struct perf_event_context *ctx,
3057 struct perf_cpu_context *cpuctx)
3059 struct perf_event *event;
3061 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3062 if (event->state <= PERF_EVENT_STATE_OFF)
3064 if (!event_filter_match(event))
3067 /* may need to reset tstamp_enabled */
3068 if (is_cgroup_event(event))
3069 perf_cgroup_mark_enabled(event, ctx);
3071 if (group_can_go_on(event, cpuctx, 1))
3072 group_sched_in(event, cpuctx, ctx);
3075 * If this pinned group hasn't been scheduled,
3076 * put it in error state.
3078 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3079 update_group_times(event);
3080 event->state = PERF_EVENT_STATE_ERROR;
3086 ctx_flexible_sched_in(struct perf_event_context *ctx,
3087 struct perf_cpu_context *cpuctx)
3089 struct perf_event *event;
3092 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3093 /* Ignore events in OFF or ERROR state */
3094 if (event->state <= PERF_EVENT_STATE_OFF)
3097 * Listen to the 'cpu' scheduling filter constraint
3100 if (!event_filter_match(event))
3103 /* may need to reset tstamp_enabled */
3104 if (is_cgroup_event(event))
3105 perf_cgroup_mark_enabled(event, ctx);
3107 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3108 if (group_sched_in(event, cpuctx, ctx))
3115 ctx_sched_in(struct perf_event_context *ctx,
3116 struct perf_cpu_context *cpuctx,
3117 enum event_type_t event_type,
3118 struct task_struct *task)
3120 int is_active = ctx->is_active;
3123 lockdep_assert_held(&ctx->lock);
3125 if (likely(!ctx->nr_events))
3128 ctx->is_active |= (event_type | EVENT_TIME);
3131 cpuctx->task_ctx = ctx;
3133 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3136 is_active ^= ctx->is_active; /* changed bits */
3138 if (is_active & EVENT_TIME) {
3139 /* start ctx time */
3141 ctx->timestamp = now;
3142 perf_cgroup_set_timestamp(task, ctx);
3146 * First go through the list and put on any pinned groups
3147 * in order to give them the best chance of going on.
3149 if (is_active & EVENT_PINNED)
3150 ctx_pinned_sched_in(ctx, cpuctx);
3152 /* Then walk through the lower prio flexible groups */
3153 if (is_active & EVENT_FLEXIBLE)
3154 ctx_flexible_sched_in(ctx, cpuctx);
3157 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3158 enum event_type_t event_type,
3159 struct task_struct *task)
3161 struct perf_event_context *ctx = &cpuctx->ctx;
3163 ctx_sched_in(ctx, cpuctx, event_type, task);
3166 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3167 struct task_struct *task)
3169 struct perf_cpu_context *cpuctx;
3171 cpuctx = __get_cpu_context(ctx);
3172 if (cpuctx->task_ctx == ctx)
3175 perf_ctx_lock(cpuctx, ctx);
3176 perf_pmu_disable(ctx->pmu);
3178 * We want to keep the following priority order:
3179 * cpu pinned (that don't need to move), task pinned,
3180 * cpu flexible, task flexible.
3182 * However, if task's ctx is not carrying any pinned
3183 * events, no need to flip the cpuctx's events around.
3185 if (!list_empty(&ctx->pinned_groups))
3186 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3187 perf_event_sched_in(cpuctx, ctx, task);
3188 perf_pmu_enable(ctx->pmu);
3189 perf_ctx_unlock(cpuctx, ctx);
3193 * Called from scheduler to add the events of the current task
3194 * with interrupts disabled.
3196 * We restore the event value and then enable it.
3198 * This does not protect us against NMI, but enable()
3199 * sets the enabled bit in the control field of event _before_
3200 * accessing the event control register. If a NMI hits, then it will
3201 * keep the event running.
3203 void __perf_event_task_sched_in(struct task_struct *prev,
3204 struct task_struct *task)
3206 struct perf_event_context *ctx;
3210 * If cgroup events exist on this CPU, then we need to check if we have
3211 * to switch in PMU state; cgroup event are system-wide mode only.
3213 * Since cgroup events are CPU events, we must schedule these in before
3214 * we schedule in the task events.
3216 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3217 perf_cgroup_sched_in(prev, task);
3219 for_each_task_context_nr(ctxn) {
3220 ctx = task->perf_event_ctxp[ctxn];
3224 perf_event_context_sched_in(ctx, task);
3227 if (atomic_read(&nr_switch_events))
3228 perf_event_switch(task, prev, true);
3230 if (__this_cpu_read(perf_sched_cb_usages))
3231 perf_pmu_sched_task(prev, task, true);
3234 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3236 u64 frequency = event->attr.sample_freq;
3237 u64 sec = NSEC_PER_SEC;
3238 u64 divisor, dividend;
3240 int count_fls, nsec_fls, frequency_fls, sec_fls;
3242 count_fls = fls64(count);
3243 nsec_fls = fls64(nsec);
3244 frequency_fls = fls64(frequency);
3248 * We got @count in @nsec, with a target of sample_freq HZ
3249 * the target period becomes:
3252 * period = -------------------
3253 * @nsec * sample_freq
3258 * Reduce accuracy by one bit such that @a and @b converge
3259 * to a similar magnitude.
3261 #define REDUCE_FLS(a, b) \
3263 if (a##_fls > b##_fls) { \
3273 * Reduce accuracy until either term fits in a u64, then proceed with
3274 * the other, so that finally we can do a u64/u64 division.
3276 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3277 REDUCE_FLS(nsec, frequency);
3278 REDUCE_FLS(sec, count);
3281 if (count_fls + sec_fls > 64) {
3282 divisor = nsec * frequency;
3284 while (count_fls + sec_fls > 64) {
3285 REDUCE_FLS(count, sec);
3289 dividend = count * sec;
3291 dividend = count * sec;
3293 while (nsec_fls + frequency_fls > 64) {
3294 REDUCE_FLS(nsec, frequency);
3298 divisor = nsec * frequency;
3304 return div64_u64(dividend, divisor);
3307 static DEFINE_PER_CPU(int, perf_throttled_count);
3308 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3310 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3312 struct hw_perf_event *hwc = &event->hw;
3313 s64 period, sample_period;
3316 period = perf_calculate_period(event, nsec, count);
3318 delta = (s64)(period - hwc->sample_period);
3319 delta = (delta + 7) / 8; /* low pass filter */
3321 sample_period = hwc->sample_period + delta;
3326 hwc->sample_period = sample_period;
3328 if (local64_read(&hwc->period_left) > 8*sample_period) {
3330 event->pmu->stop(event, PERF_EF_UPDATE);
3332 local64_set(&hwc->period_left, 0);
3335 event->pmu->start(event, PERF_EF_RELOAD);
3340 * combine freq adjustment with unthrottling to avoid two passes over the
3341 * events. At the same time, make sure, having freq events does not change
3342 * the rate of unthrottling as that would introduce bias.
3344 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3347 struct perf_event *event;
3348 struct hw_perf_event *hwc;
3349 u64 now, period = TICK_NSEC;
3353 * only need to iterate over all events iff:
3354 * - context have events in frequency mode (needs freq adjust)
3355 * - there are events to unthrottle on this cpu
3357 if (!(ctx->nr_freq || needs_unthr))
3360 raw_spin_lock(&ctx->lock);
3361 perf_pmu_disable(ctx->pmu);
3363 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3364 if (event->state != PERF_EVENT_STATE_ACTIVE)
3367 if (!event_filter_match(event))
3370 perf_pmu_disable(event->pmu);
3374 if (hwc->interrupts == MAX_INTERRUPTS) {
3375 hwc->interrupts = 0;
3376 perf_log_throttle(event, 1);
3377 event->pmu->start(event, 0);
3380 if (!event->attr.freq || !event->attr.sample_freq)
3384 * stop the event and update event->count
3386 event->pmu->stop(event, PERF_EF_UPDATE);
3388 now = local64_read(&event->count);
3389 delta = now - hwc->freq_count_stamp;
3390 hwc->freq_count_stamp = now;
3394 * reload only if value has changed
3395 * we have stopped the event so tell that
3396 * to perf_adjust_period() to avoid stopping it
3400 perf_adjust_period(event, period, delta, false);
3402 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3404 perf_pmu_enable(event->pmu);
3407 perf_pmu_enable(ctx->pmu);
3408 raw_spin_unlock(&ctx->lock);
3412 * Round-robin a context's events:
3414 static void rotate_ctx(struct perf_event_context *ctx)
3417 * Rotate the first entry last of non-pinned groups. Rotation might be
3418 * disabled by the inheritance code.
3420 if (!ctx->rotate_disable)
3421 list_rotate_left(&ctx->flexible_groups);
3424 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3426 struct perf_event_context *ctx = NULL;
3429 if (cpuctx->ctx.nr_events) {
3430 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3434 ctx = cpuctx->task_ctx;
3435 if (ctx && ctx->nr_events) {
3436 if (ctx->nr_events != ctx->nr_active)
3443 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3444 perf_pmu_disable(cpuctx->ctx.pmu);
3446 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3448 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3450 rotate_ctx(&cpuctx->ctx);
3454 perf_event_sched_in(cpuctx, ctx, current);
3456 perf_pmu_enable(cpuctx->ctx.pmu);
3457 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3463 void perf_event_task_tick(void)
3465 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3466 struct perf_event_context *ctx, *tmp;
3469 WARN_ON(!irqs_disabled());
3471 __this_cpu_inc(perf_throttled_seq);
3472 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3473 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3475 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3476 perf_adjust_freq_unthr_context(ctx, throttled);
3479 static int event_enable_on_exec(struct perf_event *event,
3480 struct perf_event_context *ctx)
3482 if (!event->attr.enable_on_exec)
3485 event->attr.enable_on_exec = 0;
3486 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3489 __perf_event_mark_enabled(event);
3495 * Enable all of a task's events that have been marked enable-on-exec.
3496 * This expects task == current.
3498 static void perf_event_enable_on_exec(int ctxn)
3500 struct perf_event_context *ctx, *clone_ctx = NULL;
3501 enum event_type_t event_type = 0;
3502 struct perf_cpu_context *cpuctx;
3503 struct perf_event *event;
3504 unsigned long flags;
3507 local_irq_save(flags);
3508 ctx = current->perf_event_ctxp[ctxn];
3509 if (!ctx || !ctx->nr_events)
3512 cpuctx = __get_cpu_context(ctx);
3513 perf_ctx_lock(cpuctx, ctx);
3514 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3515 list_for_each_entry(event, &ctx->event_list, event_entry) {
3516 enabled |= event_enable_on_exec(event, ctx);
3517 event_type |= get_event_type(event);
3521 * Unclone and reschedule this context if we enabled any event.
3524 clone_ctx = unclone_ctx(ctx);
3525 ctx_resched(cpuctx, ctx, event_type);
3527 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3529 perf_ctx_unlock(cpuctx, ctx);
3532 local_irq_restore(flags);
3538 struct perf_read_data {
3539 struct perf_event *event;
3544 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3546 u16 local_pkg, event_pkg;
3548 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3549 int local_cpu = smp_processor_id();
3551 event_pkg = topology_physical_package_id(event_cpu);
3552 local_pkg = topology_physical_package_id(local_cpu);
3554 if (event_pkg == local_pkg)
3562 * Cross CPU call to read the hardware event
3564 static void __perf_event_read(void *info)
3566 struct perf_read_data *data = info;
3567 struct perf_event *sub, *event = data->event;
3568 struct perf_event_context *ctx = event->ctx;
3569 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3570 struct pmu *pmu = event->pmu;
3573 * If this is a task context, we need to check whether it is
3574 * the current task context of this cpu. If not it has been
3575 * scheduled out before the smp call arrived. In that case
3576 * event->count would have been updated to a recent sample
3577 * when the event was scheduled out.
3579 if (ctx->task && cpuctx->task_ctx != ctx)
3582 raw_spin_lock(&ctx->lock);
3583 if (ctx->is_active) {
3584 update_context_time(ctx);
3585 update_cgrp_time_from_event(event);
3588 update_event_times(event);
3589 if (event->state != PERF_EVENT_STATE_ACTIVE)
3598 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3602 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3603 update_event_times(sub);
3604 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3606 * Use sibling's PMU rather than @event's since
3607 * sibling could be on different (eg: software) PMU.
3609 sub->pmu->read(sub);
3613 data->ret = pmu->commit_txn(pmu);
3616 raw_spin_unlock(&ctx->lock);
3619 static inline u64 perf_event_count(struct perf_event *event)
3621 if (event->pmu->count)
3622 return event->pmu->count(event);
3624 return __perf_event_count(event);
3628 * NMI-safe method to read a local event, that is an event that
3630 * - either for the current task, or for this CPU
3631 * - does not have inherit set, for inherited task events
3632 * will not be local and we cannot read them atomically
3633 * - must not have a pmu::count method
3635 u64 perf_event_read_local(struct perf_event *event)
3637 unsigned long flags;
3641 * Disabling interrupts avoids all counter scheduling (context
3642 * switches, timer based rotation and IPIs).
3644 local_irq_save(flags);
3646 /* If this is a per-task event, it must be for current */
3647 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3648 event->hw.target != current);
3650 /* If this is a per-CPU event, it must be for this CPU */
3651 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3652 event->cpu != smp_processor_id());
3655 * It must not be an event with inherit set, we cannot read
3656 * all child counters from atomic context.
3658 WARN_ON_ONCE(event->attr.inherit);
3661 * It must not have a pmu::count method, those are not
3664 WARN_ON_ONCE(event->pmu->count);
3667 * If the event is currently on this CPU, its either a per-task event,
3668 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3671 if (event->oncpu == smp_processor_id())
3672 event->pmu->read(event);
3674 val = local64_read(&event->count);
3675 local_irq_restore(flags);
3680 static int perf_event_read(struct perf_event *event, bool group)
3682 int event_cpu, ret = 0;
3685 * If event is enabled and currently active on a CPU, update the
3686 * value in the event structure:
3688 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3689 struct perf_read_data data = {
3695 event_cpu = READ_ONCE(event->oncpu);
3696 if ((unsigned)event_cpu >= nr_cpu_ids)
3700 event_cpu = __perf_event_read_cpu(event, event_cpu);
3703 * Purposely ignore the smp_call_function_single() return
3706 * If event_cpu isn't a valid CPU it means the event got
3707 * scheduled out and that will have updated the event count.
3709 * Therefore, either way, we'll have an up-to-date event count
3712 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3715 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3716 struct perf_event_context *ctx = event->ctx;
3717 unsigned long flags;
3719 raw_spin_lock_irqsave(&ctx->lock, flags);
3721 * may read while context is not active
3722 * (e.g., thread is blocked), in that case
3723 * we cannot update context time
3725 if (ctx->is_active) {
3726 update_context_time(ctx);
3727 update_cgrp_time_from_event(event);
3730 update_group_times(event);
3732 update_event_times(event);
3733 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3740 * Initialize the perf_event context in a task_struct:
3742 static void __perf_event_init_context(struct perf_event_context *ctx)
3744 raw_spin_lock_init(&ctx->lock);
3745 mutex_init(&ctx->mutex);
3746 INIT_LIST_HEAD(&ctx->active_ctx_list);
3747 INIT_LIST_HEAD(&ctx->pinned_groups);
3748 INIT_LIST_HEAD(&ctx->flexible_groups);
3749 INIT_LIST_HEAD(&ctx->event_list);
3750 atomic_set(&ctx->refcount, 1);
3753 static struct perf_event_context *
3754 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3756 struct perf_event_context *ctx;
3758 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3762 __perf_event_init_context(ctx);
3765 get_task_struct(task);
3772 static struct task_struct *
3773 find_lively_task_by_vpid(pid_t vpid)
3775 struct task_struct *task;
3781 task = find_task_by_vpid(vpid);
3783 get_task_struct(task);
3787 return ERR_PTR(-ESRCH);
3793 * Returns a matching context with refcount and pincount.
3795 static struct perf_event_context *
3796 find_get_context(struct pmu *pmu, struct task_struct *task,
3797 struct perf_event *event)
3799 struct perf_event_context *ctx, *clone_ctx = NULL;
3800 struct perf_cpu_context *cpuctx;
3801 void *task_ctx_data = NULL;
3802 unsigned long flags;
3804 int cpu = event->cpu;
3807 /* Must be root to operate on a CPU event: */
3808 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3809 return ERR_PTR(-EACCES);
3811 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3820 ctxn = pmu->task_ctx_nr;
3824 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3825 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3826 if (!task_ctx_data) {
3833 ctx = perf_lock_task_context(task, ctxn, &flags);
3835 clone_ctx = unclone_ctx(ctx);
3838 if (task_ctx_data && !ctx->task_ctx_data) {
3839 ctx->task_ctx_data = task_ctx_data;
3840 task_ctx_data = NULL;
3842 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3847 ctx = alloc_perf_context(pmu, task);
3852 if (task_ctx_data) {
3853 ctx->task_ctx_data = task_ctx_data;
3854 task_ctx_data = NULL;
3858 mutex_lock(&task->perf_event_mutex);
3860 * If it has already passed perf_event_exit_task().
3861 * we must see PF_EXITING, it takes this mutex too.
3863 if (task->flags & PF_EXITING)
3865 else if (task->perf_event_ctxp[ctxn])
3870 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3872 mutex_unlock(&task->perf_event_mutex);
3874 if (unlikely(err)) {
3883 kfree(task_ctx_data);
3887 kfree(task_ctx_data);
3888 return ERR_PTR(err);
3891 static void perf_event_free_filter(struct perf_event *event);
3892 static void perf_event_free_bpf_prog(struct perf_event *event);
3894 static void free_event_rcu(struct rcu_head *head)
3896 struct perf_event *event;
3898 event = container_of(head, struct perf_event, rcu_head);
3900 put_pid_ns(event->ns);
3901 perf_event_free_filter(event);
3905 static void ring_buffer_attach(struct perf_event *event,
3906 struct ring_buffer *rb);
3908 static void detach_sb_event(struct perf_event *event)
3910 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3912 raw_spin_lock(&pel->lock);
3913 list_del_rcu(&event->sb_list);
3914 raw_spin_unlock(&pel->lock);
3917 static bool is_sb_event(struct perf_event *event)
3919 struct perf_event_attr *attr = &event->attr;
3924 if (event->attach_state & PERF_ATTACH_TASK)
3927 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3928 attr->comm || attr->comm_exec ||
3930 attr->context_switch)
3935 static void unaccount_pmu_sb_event(struct perf_event *event)
3937 if (is_sb_event(event))
3938 detach_sb_event(event);
3941 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3946 if (is_cgroup_event(event))
3947 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3950 #ifdef CONFIG_NO_HZ_FULL
3951 static DEFINE_SPINLOCK(nr_freq_lock);
3954 static void unaccount_freq_event_nohz(void)
3956 #ifdef CONFIG_NO_HZ_FULL
3957 spin_lock(&nr_freq_lock);
3958 if (atomic_dec_and_test(&nr_freq_events))
3959 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3960 spin_unlock(&nr_freq_lock);
3964 static void unaccount_freq_event(void)
3966 if (tick_nohz_full_enabled())
3967 unaccount_freq_event_nohz();
3969 atomic_dec(&nr_freq_events);
3972 static void unaccount_event(struct perf_event *event)
3979 if (event->attach_state & PERF_ATTACH_TASK)
3981 if (event->attr.mmap || event->attr.mmap_data)
3982 atomic_dec(&nr_mmap_events);
3983 if (event->attr.comm)
3984 atomic_dec(&nr_comm_events);
3985 if (event->attr.namespaces)
3986 atomic_dec(&nr_namespaces_events);
3987 if (event->attr.task)
3988 atomic_dec(&nr_task_events);
3989 if (event->attr.freq)
3990 unaccount_freq_event();
3991 if (event->attr.context_switch) {
3993 atomic_dec(&nr_switch_events);
3995 if (is_cgroup_event(event))
3997 if (has_branch_stack(event))
4001 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4002 schedule_delayed_work(&perf_sched_work, HZ);
4005 unaccount_event_cpu(event, event->cpu);
4007 unaccount_pmu_sb_event(event);
4010 static void perf_sched_delayed(struct work_struct *work)
4012 mutex_lock(&perf_sched_mutex);
4013 if (atomic_dec_and_test(&perf_sched_count))
4014 static_branch_disable(&perf_sched_events);
4015 mutex_unlock(&perf_sched_mutex);
4019 * The following implement mutual exclusion of events on "exclusive" pmus
4020 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4021 * at a time, so we disallow creating events that might conflict, namely:
4023 * 1) cpu-wide events in the presence of per-task events,
4024 * 2) per-task events in the presence of cpu-wide events,
4025 * 3) two matching events on the same context.
4027 * The former two cases are handled in the allocation path (perf_event_alloc(),
4028 * _free_event()), the latter -- before the first perf_install_in_context().
4030 static int exclusive_event_init(struct perf_event *event)
4032 struct pmu *pmu = event->pmu;
4034 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4038 * Prevent co-existence of per-task and cpu-wide events on the
4039 * same exclusive pmu.
4041 * Negative pmu::exclusive_cnt means there are cpu-wide
4042 * events on this "exclusive" pmu, positive means there are
4045 * Since this is called in perf_event_alloc() path, event::ctx
4046 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4047 * to mean "per-task event", because unlike other attach states it
4048 * never gets cleared.
4050 if (event->attach_state & PERF_ATTACH_TASK) {
4051 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4054 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4061 static void exclusive_event_destroy(struct perf_event *event)
4063 struct pmu *pmu = event->pmu;
4065 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4068 /* see comment in exclusive_event_init() */
4069 if (event->attach_state & PERF_ATTACH_TASK)
4070 atomic_dec(&pmu->exclusive_cnt);
4072 atomic_inc(&pmu->exclusive_cnt);
4075 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4077 if ((e1->pmu == e2->pmu) &&
4078 (e1->cpu == e2->cpu ||
4085 /* Called under the same ctx::mutex as perf_install_in_context() */
4086 static bool exclusive_event_installable(struct perf_event *event,
4087 struct perf_event_context *ctx)
4089 struct perf_event *iter_event;
4090 struct pmu *pmu = event->pmu;
4092 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4095 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4096 if (exclusive_event_match(iter_event, event))
4103 static void perf_addr_filters_splice(struct perf_event *event,
4104 struct list_head *head);
4106 static void _free_event(struct perf_event *event)
4108 irq_work_sync(&event->pending);
4110 unaccount_event(event);
4114 * Can happen when we close an event with re-directed output.
4116 * Since we have a 0 refcount, perf_mmap_close() will skip
4117 * over us; possibly making our ring_buffer_put() the last.
4119 mutex_lock(&event->mmap_mutex);
4120 ring_buffer_attach(event, NULL);
4121 mutex_unlock(&event->mmap_mutex);
4124 if (is_cgroup_event(event))
4125 perf_detach_cgroup(event);
4127 if (!event->parent) {
4128 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4129 put_callchain_buffers();
4132 perf_event_free_bpf_prog(event);
4133 perf_addr_filters_splice(event, NULL);
4134 kfree(event->addr_filters_offs);
4137 event->destroy(event);
4140 put_ctx(event->ctx);
4142 exclusive_event_destroy(event);
4143 module_put(event->pmu->module);
4145 call_rcu(&event->rcu_head, free_event_rcu);
4149 * Used to free events which have a known refcount of 1, such as in error paths
4150 * where the event isn't exposed yet and inherited events.
4152 static void free_event(struct perf_event *event)
4154 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4155 "unexpected event refcount: %ld; ptr=%p\n",
4156 atomic_long_read(&event->refcount), event)) {
4157 /* leak to avoid use-after-free */
4165 * Remove user event from the owner task.
4167 static void perf_remove_from_owner(struct perf_event *event)
4169 struct task_struct *owner;
4173 * Matches the smp_store_release() in perf_event_exit_task(). If we
4174 * observe !owner it means the list deletion is complete and we can
4175 * indeed free this event, otherwise we need to serialize on
4176 * owner->perf_event_mutex.
4178 owner = lockless_dereference(event->owner);
4181 * Since delayed_put_task_struct() also drops the last
4182 * task reference we can safely take a new reference
4183 * while holding the rcu_read_lock().
4185 get_task_struct(owner);
4191 * If we're here through perf_event_exit_task() we're already
4192 * holding ctx->mutex which would be an inversion wrt. the
4193 * normal lock order.
4195 * However we can safely take this lock because its the child
4198 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4201 * We have to re-check the event->owner field, if it is cleared
4202 * we raced with perf_event_exit_task(), acquiring the mutex
4203 * ensured they're done, and we can proceed with freeing the
4207 list_del_init(&event->owner_entry);
4208 smp_store_release(&event->owner, NULL);
4210 mutex_unlock(&owner->perf_event_mutex);
4211 put_task_struct(owner);
4215 static void put_event(struct perf_event *event)
4217 if (!atomic_long_dec_and_test(&event->refcount))
4224 * Kill an event dead; while event:refcount will preserve the event
4225 * object, it will not preserve its functionality. Once the last 'user'
4226 * gives up the object, we'll destroy the thing.
4228 int perf_event_release_kernel(struct perf_event *event)
4230 struct perf_event_context *ctx = event->ctx;
4231 struct perf_event *child, *tmp;
4234 * If we got here through err_file: fput(event_file); we will not have
4235 * attached to a context yet.
4238 WARN_ON_ONCE(event->attach_state &
4239 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4243 if (!is_kernel_event(event))
4244 perf_remove_from_owner(event);
4246 ctx = perf_event_ctx_lock(event);
4247 WARN_ON_ONCE(ctx->parent_ctx);
4248 perf_remove_from_context(event, DETACH_GROUP);
4250 raw_spin_lock_irq(&ctx->lock);
4252 * Mark this event as STATE_DEAD, there is no external reference to it
4255 * Anybody acquiring event->child_mutex after the below loop _must_
4256 * also see this, most importantly inherit_event() which will avoid
4257 * placing more children on the list.
4259 * Thus this guarantees that we will in fact observe and kill _ALL_
4262 event->state = PERF_EVENT_STATE_DEAD;
4263 raw_spin_unlock_irq(&ctx->lock);
4265 perf_event_ctx_unlock(event, ctx);
4268 mutex_lock(&event->child_mutex);
4269 list_for_each_entry(child, &event->child_list, child_list) {
4272 * Cannot change, child events are not migrated, see the
4273 * comment with perf_event_ctx_lock_nested().
4275 ctx = lockless_dereference(child->ctx);
4277 * Since child_mutex nests inside ctx::mutex, we must jump
4278 * through hoops. We start by grabbing a reference on the ctx.
4280 * Since the event cannot get freed while we hold the
4281 * child_mutex, the context must also exist and have a !0
4287 * Now that we have a ctx ref, we can drop child_mutex, and
4288 * acquire ctx::mutex without fear of it going away. Then we
4289 * can re-acquire child_mutex.
4291 mutex_unlock(&event->child_mutex);
4292 mutex_lock(&ctx->mutex);
4293 mutex_lock(&event->child_mutex);
4296 * Now that we hold ctx::mutex and child_mutex, revalidate our
4297 * state, if child is still the first entry, it didn't get freed
4298 * and we can continue doing so.
4300 tmp = list_first_entry_or_null(&event->child_list,
4301 struct perf_event, child_list);
4303 perf_remove_from_context(child, DETACH_GROUP);
4304 list_del(&child->child_list);
4307 * This matches the refcount bump in inherit_event();
4308 * this can't be the last reference.
4313 mutex_unlock(&event->child_mutex);
4314 mutex_unlock(&ctx->mutex);
4318 mutex_unlock(&event->child_mutex);
4321 put_event(event); /* Must be the 'last' reference */
4324 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4327 * Called when the last reference to the file is gone.
4329 static int perf_release(struct inode *inode, struct file *file)
4331 perf_event_release_kernel(file->private_data);
4335 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4337 struct perf_event *child;
4343 mutex_lock(&event->child_mutex);
4345 (void)perf_event_read(event, false);
4346 total += perf_event_count(event);
4348 *enabled += event->total_time_enabled +
4349 atomic64_read(&event->child_total_time_enabled);
4350 *running += event->total_time_running +
4351 atomic64_read(&event->child_total_time_running);
4353 list_for_each_entry(child, &event->child_list, child_list) {
4354 (void)perf_event_read(child, false);
4355 total += perf_event_count(child);
4356 *enabled += child->total_time_enabled;
4357 *running += child->total_time_running;
4359 mutex_unlock(&event->child_mutex);
4363 EXPORT_SYMBOL_GPL(perf_event_read_value);
4365 static int __perf_read_group_add(struct perf_event *leader,
4366 u64 read_format, u64 *values)
4368 struct perf_event *sub;
4369 int n = 1; /* skip @nr */
4372 ret = perf_event_read(leader, true);
4377 * Since we co-schedule groups, {enabled,running} times of siblings
4378 * will be identical to those of the leader, so we only publish one
4381 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4382 values[n++] += leader->total_time_enabled +
4383 atomic64_read(&leader->child_total_time_enabled);
4386 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4387 values[n++] += leader->total_time_running +
4388 atomic64_read(&leader->child_total_time_running);
4392 * Write {count,id} tuples for every sibling.
4394 values[n++] += perf_event_count(leader);
4395 if (read_format & PERF_FORMAT_ID)
4396 values[n++] = primary_event_id(leader);
4398 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4399 values[n++] += perf_event_count(sub);
4400 if (read_format & PERF_FORMAT_ID)
4401 values[n++] = primary_event_id(sub);
4407 static int perf_read_group(struct perf_event *event,
4408 u64 read_format, char __user *buf)
4410 struct perf_event *leader = event->group_leader, *child;
4411 struct perf_event_context *ctx = leader->ctx;
4415 lockdep_assert_held(&ctx->mutex);
4417 values = kzalloc(event->read_size, GFP_KERNEL);
4421 values[0] = 1 + leader->nr_siblings;
4424 * By locking the child_mutex of the leader we effectively
4425 * lock the child list of all siblings.. XXX explain how.
4427 mutex_lock(&leader->child_mutex);
4429 ret = __perf_read_group_add(leader, read_format, values);
4433 list_for_each_entry(child, &leader->child_list, child_list) {
4434 ret = __perf_read_group_add(child, read_format, values);
4439 mutex_unlock(&leader->child_mutex);
4441 ret = event->read_size;
4442 if (copy_to_user(buf, values, event->read_size))
4447 mutex_unlock(&leader->child_mutex);
4453 static int perf_read_one(struct perf_event *event,
4454 u64 read_format, char __user *buf)
4456 u64 enabled, running;
4460 values[n++] = perf_event_read_value(event, &enabled, &running);
4461 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4462 values[n++] = enabled;
4463 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4464 values[n++] = running;
4465 if (read_format & PERF_FORMAT_ID)
4466 values[n++] = primary_event_id(event);
4468 if (copy_to_user(buf, values, n * sizeof(u64)))
4471 return n * sizeof(u64);
4474 static bool is_event_hup(struct perf_event *event)
4478 if (event->state > PERF_EVENT_STATE_EXIT)
4481 mutex_lock(&event->child_mutex);
4482 no_children = list_empty(&event->child_list);
4483 mutex_unlock(&event->child_mutex);
4488 * Read the performance event - simple non blocking version for now
4491 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4493 u64 read_format = event->attr.read_format;
4497 * Return end-of-file for a read on a event that is in
4498 * error state (i.e. because it was pinned but it couldn't be
4499 * scheduled on to the CPU at some point).
4501 if (event->state == PERF_EVENT_STATE_ERROR)
4504 if (count < event->read_size)
4507 WARN_ON_ONCE(event->ctx->parent_ctx);
4508 if (read_format & PERF_FORMAT_GROUP)
4509 ret = perf_read_group(event, read_format, buf);
4511 ret = perf_read_one(event, read_format, buf);
4517 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4519 struct perf_event *event = file->private_data;
4520 struct perf_event_context *ctx;
4523 ctx = perf_event_ctx_lock(event);
4524 ret = __perf_read(event, buf, count);
4525 perf_event_ctx_unlock(event, ctx);
4530 static unsigned int perf_poll(struct file *file, poll_table *wait)
4532 struct perf_event *event = file->private_data;
4533 struct ring_buffer *rb;
4534 unsigned int events = POLLHUP;
4536 poll_wait(file, &event->waitq, wait);
4538 if (is_event_hup(event))
4542 * Pin the event->rb by taking event->mmap_mutex; otherwise
4543 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4545 mutex_lock(&event->mmap_mutex);
4548 events = atomic_xchg(&rb->poll, 0);
4549 mutex_unlock(&event->mmap_mutex);
4553 static void _perf_event_reset(struct perf_event *event)
4555 (void)perf_event_read(event, false);
4556 local64_set(&event->count, 0);
4557 perf_event_update_userpage(event);
4561 * Holding the top-level event's child_mutex means that any
4562 * descendant process that has inherited this event will block
4563 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4564 * task existence requirements of perf_event_enable/disable.
4566 static void perf_event_for_each_child(struct perf_event *event,
4567 void (*func)(struct perf_event *))
4569 struct perf_event *child;
4571 WARN_ON_ONCE(event->ctx->parent_ctx);
4573 mutex_lock(&event->child_mutex);
4575 list_for_each_entry(child, &event->child_list, child_list)
4577 mutex_unlock(&event->child_mutex);
4580 static void perf_event_for_each(struct perf_event *event,
4581 void (*func)(struct perf_event *))
4583 struct perf_event_context *ctx = event->ctx;
4584 struct perf_event *sibling;
4586 lockdep_assert_held(&ctx->mutex);
4588 event = event->group_leader;
4590 perf_event_for_each_child(event, func);
4591 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4592 perf_event_for_each_child(sibling, func);
4595 static void __perf_event_period(struct perf_event *event,
4596 struct perf_cpu_context *cpuctx,
4597 struct perf_event_context *ctx,
4600 u64 value = *((u64 *)info);
4603 if (event->attr.freq) {
4604 event->attr.sample_freq = value;
4606 event->attr.sample_period = value;
4607 event->hw.sample_period = value;
4610 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4612 perf_pmu_disable(ctx->pmu);
4614 * We could be throttled; unthrottle now to avoid the tick
4615 * trying to unthrottle while we already re-started the event.
4617 if (event->hw.interrupts == MAX_INTERRUPTS) {
4618 event->hw.interrupts = 0;
4619 perf_log_throttle(event, 1);
4621 event->pmu->stop(event, PERF_EF_UPDATE);
4624 local64_set(&event->hw.period_left, 0);
4627 event->pmu->start(event, PERF_EF_RELOAD);
4628 perf_pmu_enable(ctx->pmu);
4632 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4636 if (!is_sampling_event(event))
4639 if (copy_from_user(&value, arg, sizeof(value)))
4645 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4648 event_function_call(event, __perf_event_period, &value);
4653 static const struct file_operations perf_fops;
4655 static inline int perf_fget_light(int fd, struct fd *p)
4657 struct fd f = fdget(fd);
4661 if (f.file->f_op != &perf_fops) {
4669 static int perf_event_set_output(struct perf_event *event,
4670 struct perf_event *output_event);
4671 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4672 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4674 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4676 void (*func)(struct perf_event *);
4680 case PERF_EVENT_IOC_ENABLE:
4681 func = _perf_event_enable;
4683 case PERF_EVENT_IOC_DISABLE:
4684 func = _perf_event_disable;
4686 case PERF_EVENT_IOC_RESET:
4687 func = _perf_event_reset;
4690 case PERF_EVENT_IOC_REFRESH:
4691 return _perf_event_refresh(event, arg);
4693 case PERF_EVENT_IOC_PERIOD:
4694 return perf_event_period(event, (u64 __user *)arg);
4696 case PERF_EVENT_IOC_ID:
4698 u64 id = primary_event_id(event);
4700 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4705 case PERF_EVENT_IOC_SET_OUTPUT:
4709 struct perf_event *output_event;
4711 ret = perf_fget_light(arg, &output);
4714 output_event = output.file->private_data;
4715 ret = perf_event_set_output(event, output_event);
4718 ret = perf_event_set_output(event, NULL);
4723 case PERF_EVENT_IOC_SET_FILTER:
4724 return perf_event_set_filter(event, (void __user *)arg);
4726 case PERF_EVENT_IOC_SET_BPF:
4727 return perf_event_set_bpf_prog(event, arg);
4729 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4730 struct ring_buffer *rb;
4733 rb = rcu_dereference(event->rb);
4734 if (!rb || !rb->nr_pages) {
4738 rb_toggle_paused(rb, !!arg);
4746 if (flags & PERF_IOC_FLAG_GROUP)
4747 perf_event_for_each(event, func);
4749 perf_event_for_each_child(event, func);
4754 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4756 struct perf_event *event = file->private_data;
4757 struct perf_event_context *ctx;
4760 ctx = perf_event_ctx_lock(event);
4761 ret = _perf_ioctl(event, cmd, arg);
4762 perf_event_ctx_unlock(event, ctx);
4767 #ifdef CONFIG_COMPAT
4768 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4771 switch (_IOC_NR(cmd)) {
4772 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4773 case _IOC_NR(PERF_EVENT_IOC_ID):
4774 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4775 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4776 cmd &= ~IOCSIZE_MASK;
4777 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4781 return perf_ioctl(file, cmd, arg);
4784 # define perf_compat_ioctl NULL
4787 int perf_event_task_enable(void)
4789 struct perf_event_context *ctx;
4790 struct perf_event *event;
4792 mutex_lock(¤t->perf_event_mutex);
4793 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4794 ctx = perf_event_ctx_lock(event);
4795 perf_event_for_each_child(event, _perf_event_enable);
4796 perf_event_ctx_unlock(event, ctx);
4798 mutex_unlock(¤t->perf_event_mutex);
4803 int perf_event_task_disable(void)
4805 struct perf_event_context *ctx;
4806 struct perf_event *event;
4808 mutex_lock(¤t->perf_event_mutex);
4809 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4810 ctx = perf_event_ctx_lock(event);
4811 perf_event_for_each_child(event, _perf_event_disable);
4812 perf_event_ctx_unlock(event, ctx);
4814 mutex_unlock(¤t->perf_event_mutex);
4819 static int perf_event_index(struct perf_event *event)
4821 if (event->hw.state & PERF_HES_STOPPED)
4824 if (event->state != PERF_EVENT_STATE_ACTIVE)
4827 return event->pmu->event_idx(event);
4830 static void calc_timer_values(struct perf_event *event,
4837 *now = perf_clock();
4838 ctx_time = event->shadow_ctx_time + *now;
4839 *enabled = ctx_time - event->tstamp_enabled;
4840 *running = ctx_time - event->tstamp_running;
4843 static void perf_event_init_userpage(struct perf_event *event)
4845 struct perf_event_mmap_page *userpg;
4846 struct ring_buffer *rb;
4849 rb = rcu_dereference(event->rb);
4853 userpg = rb->user_page;
4855 /* Allow new userspace to detect that bit 0 is deprecated */
4856 userpg->cap_bit0_is_deprecated = 1;
4857 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4858 userpg->data_offset = PAGE_SIZE;
4859 userpg->data_size = perf_data_size(rb);
4865 void __weak arch_perf_update_userpage(
4866 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4871 * Callers need to ensure there can be no nesting of this function, otherwise
4872 * the seqlock logic goes bad. We can not serialize this because the arch
4873 * code calls this from NMI context.
4875 void perf_event_update_userpage(struct perf_event *event)
4877 struct perf_event_mmap_page *userpg;
4878 struct ring_buffer *rb;
4879 u64 enabled, running, now;
4882 rb = rcu_dereference(event->rb);
4887 * compute total_time_enabled, total_time_running
4888 * based on snapshot values taken when the event
4889 * was last scheduled in.
4891 * we cannot simply called update_context_time()
4892 * because of locking issue as we can be called in
4895 calc_timer_values(event, &now, &enabled, &running);
4897 userpg = rb->user_page;
4899 * Disable preemption so as to not let the corresponding user-space
4900 * spin too long if we get preempted.
4905 userpg->index = perf_event_index(event);
4906 userpg->offset = perf_event_count(event);
4908 userpg->offset -= local64_read(&event->hw.prev_count);
4910 userpg->time_enabled = enabled +
4911 atomic64_read(&event->child_total_time_enabled);
4913 userpg->time_running = running +
4914 atomic64_read(&event->child_total_time_running);
4916 arch_perf_update_userpage(event, userpg, now);
4925 static int perf_mmap_fault(struct vm_fault *vmf)
4927 struct perf_event *event = vmf->vma->vm_file->private_data;
4928 struct ring_buffer *rb;
4929 int ret = VM_FAULT_SIGBUS;
4931 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4932 if (vmf->pgoff == 0)
4938 rb = rcu_dereference(event->rb);
4942 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4945 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4949 get_page(vmf->page);
4950 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4951 vmf->page->index = vmf->pgoff;
4960 static void ring_buffer_attach(struct perf_event *event,
4961 struct ring_buffer *rb)
4963 struct ring_buffer *old_rb = NULL;
4964 unsigned long flags;
4968 * Should be impossible, we set this when removing
4969 * event->rb_entry and wait/clear when adding event->rb_entry.
4971 WARN_ON_ONCE(event->rcu_pending);
4974 spin_lock_irqsave(&old_rb->event_lock, flags);
4975 list_del_rcu(&event->rb_entry);
4976 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4978 event->rcu_batches = get_state_synchronize_rcu();
4979 event->rcu_pending = 1;
4983 if (event->rcu_pending) {
4984 cond_synchronize_rcu(event->rcu_batches);
4985 event->rcu_pending = 0;
4988 spin_lock_irqsave(&rb->event_lock, flags);
4989 list_add_rcu(&event->rb_entry, &rb->event_list);
4990 spin_unlock_irqrestore(&rb->event_lock, flags);
4994 * Avoid racing with perf_mmap_close(AUX): stop the event
4995 * before swizzling the event::rb pointer; if it's getting
4996 * unmapped, its aux_mmap_count will be 0 and it won't
4997 * restart. See the comment in __perf_pmu_output_stop().
4999 * Data will inevitably be lost when set_output is done in
5000 * mid-air, but then again, whoever does it like this is
5001 * not in for the data anyway.
5004 perf_event_stop(event, 0);
5006 rcu_assign_pointer(event->rb, rb);
5009 ring_buffer_put(old_rb);
5011 * Since we detached before setting the new rb, so that we
5012 * could attach the new rb, we could have missed a wakeup.
5015 wake_up_all(&event->waitq);
5019 static void ring_buffer_wakeup(struct perf_event *event)
5021 struct ring_buffer *rb;
5024 rb = rcu_dereference(event->rb);
5026 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5027 wake_up_all(&event->waitq);
5032 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5034 struct ring_buffer *rb;
5037 rb = rcu_dereference(event->rb);
5039 if (!atomic_inc_not_zero(&rb->refcount))
5047 void ring_buffer_put(struct ring_buffer *rb)
5049 if (!atomic_dec_and_test(&rb->refcount))
5052 WARN_ON_ONCE(!list_empty(&rb->event_list));
5054 call_rcu(&rb->rcu_head, rb_free_rcu);
5057 static void perf_mmap_open(struct vm_area_struct *vma)
5059 struct perf_event *event = vma->vm_file->private_data;
5061 atomic_inc(&event->mmap_count);
5062 atomic_inc(&event->rb->mmap_count);
5065 atomic_inc(&event->rb->aux_mmap_count);
5067 if (event->pmu->event_mapped)
5068 event->pmu->event_mapped(event);
5071 static void perf_pmu_output_stop(struct perf_event *event);
5074 * A buffer can be mmap()ed multiple times; either directly through the same
5075 * event, or through other events by use of perf_event_set_output().
5077 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5078 * the buffer here, where we still have a VM context. This means we need
5079 * to detach all events redirecting to us.
5081 static void perf_mmap_close(struct vm_area_struct *vma)
5083 struct perf_event *event = vma->vm_file->private_data;
5085 struct ring_buffer *rb = ring_buffer_get(event);
5086 struct user_struct *mmap_user = rb->mmap_user;
5087 int mmap_locked = rb->mmap_locked;
5088 unsigned long size = perf_data_size(rb);
5090 if (event->pmu->event_unmapped)
5091 event->pmu->event_unmapped(event);
5094 * rb->aux_mmap_count will always drop before rb->mmap_count and
5095 * event->mmap_count, so it is ok to use event->mmap_mutex to
5096 * serialize with perf_mmap here.
5098 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5099 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5101 * Stop all AUX events that are writing to this buffer,
5102 * so that we can free its AUX pages and corresponding PMU
5103 * data. Note that after rb::aux_mmap_count dropped to zero,
5104 * they won't start any more (see perf_aux_output_begin()).
5106 perf_pmu_output_stop(event);
5108 /* now it's safe to free the pages */
5109 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5110 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5112 /* this has to be the last one */
5114 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5116 mutex_unlock(&event->mmap_mutex);
5119 atomic_dec(&rb->mmap_count);
5121 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5124 ring_buffer_attach(event, NULL);
5125 mutex_unlock(&event->mmap_mutex);
5127 /* If there's still other mmap()s of this buffer, we're done. */
5128 if (atomic_read(&rb->mmap_count))
5132 * No other mmap()s, detach from all other events that might redirect
5133 * into the now unreachable buffer. Somewhat complicated by the
5134 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5138 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5139 if (!atomic_long_inc_not_zero(&event->refcount)) {
5141 * This event is en-route to free_event() which will
5142 * detach it and remove it from the list.
5148 mutex_lock(&event->mmap_mutex);
5150 * Check we didn't race with perf_event_set_output() which can
5151 * swizzle the rb from under us while we were waiting to
5152 * acquire mmap_mutex.
5154 * If we find a different rb; ignore this event, a next
5155 * iteration will no longer find it on the list. We have to
5156 * still restart the iteration to make sure we're not now
5157 * iterating the wrong list.
5159 if (event->rb == rb)
5160 ring_buffer_attach(event, NULL);
5162 mutex_unlock(&event->mmap_mutex);
5166 * Restart the iteration; either we're on the wrong list or
5167 * destroyed its integrity by doing a deletion.
5174 * It could be there's still a few 0-ref events on the list; they'll
5175 * get cleaned up by free_event() -- they'll also still have their
5176 * ref on the rb and will free it whenever they are done with it.
5178 * Aside from that, this buffer is 'fully' detached and unmapped,
5179 * undo the VM accounting.
5182 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5183 vma->vm_mm->pinned_vm -= mmap_locked;
5184 free_uid(mmap_user);
5187 ring_buffer_put(rb); /* could be last */
5190 static const struct vm_operations_struct perf_mmap_vmops = {
5191 .open = perf_mmap_open,
5192 .close = perf_mmap_close, /* non mergable */
5193 .fault = perf_mmap_fault,
5194 .page_mkwrite = perf_mmap_fault,
5197 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5199 struct perf_event *event = file->private_data;
5200 unsigned long user_locked, user_lock_limit;
5201 struct user_struct *user = current_user();
5202 unsigned long locked, lock_limit;
5203 struct ring_buffer *rb = NULL;
5204 unsigned long vma_size;
5205 unsigned long nr_pages;
5206 long user_extra = 0, extra = 0;
5207 int ret = 0, flags = 0;
5210 * Don't allow mmap() of inherited per-task counters. This would
5211 * create a performance issue due to all children writing to the
5214 if (event->cpu == -1 && event->attr.inherit)
5217 if (!(vma->vm_flags & VM_SHARED))
5220 vma_size = vma->vm_end - vma->vm_start;
5222 if (vma->vm_pgoff == 0) {
5223 nr_pages = (vma_size / PAGE_SIZE) - 1;
5226 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5227 * mapped, all subsequent mappings should have the same size
5228 * and offset. Must be above the normal perf buffer.
5230 u64 aux_offset, aux_size;
5235 nr_pages = vma_size / PAGE_SIZE;
5237 mutex_lock(&event->mmap_mutex);
5244 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5245 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5247 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5250 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5253 /* already mapped with a different offset */
5254 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5257 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5260 /* already mapped with a different size */
5261 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5264 if (!is_power_of_2(nr_pages))
5267 if (!atomic_inc_not_zero(&rb->mmap_count))
5270 if (rb_has_aux(rb)) {
5271 atomic_inc(&rb->aux_mmap_count);
5276 atomic_set(&rb->aux_mmap_count, 1);
5277 user_extra = nr_pages;
5283 * If we have rb pages ensure they're a power-of-two number, so we
5284 * can do bitmasks instead of modulo.
5286 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5289 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5292 WARN_ON_ONCE(event->ctx->parent_ctx);
5294 mutex_lock(&event->mmap_mutex);
5296 if (event->rb->nr_pages != nr_pages) {
5301 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5303 * Raced against perf_mmap_close() through
5304 * perf_event_set_output(). Try again, hope for better
5307 mutex_unlock(&event->mmap_mutex);
5314 user_extra = nr_pages + 1;
5317 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5320 * Increase the limit linearly with more CPUs:
5322 user_lock_limit *= num_online_cpus();
5324 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5326 if (user_locked > user_lock_limit)
5327 extra = user_locked - user_lock_limit;
5329 lock_limit = rlimit(RLIMIT_MEMLOCK);
5330 lock_limit >>= PAGE_SHIFT;
5331 locked = vma->vm_mm->pinned_vm + extra;
5333 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5334 !capable(CAP_IPC_LOCK)) {
5339 WARN_ON(!rb && event->rb);
5341 if (vma->vm_flags & VM_WRITE)
5342 flags |= RING_BUFFER_WRITABLE;
5345 rb = rb_alloc(nr_pages,
5346 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5354 atomic_set(&rb->mmap_count, 1);
5355 rb->mmap_user = get_current_user();
5356 rb->mmap_locked = extra;
5358 ring_buffer_attach(event, rb);
5360 perf_event_init_userpage(event);
5361 perf_event_update_userpage(event);
5363 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5364 event->attr.aux_watermark, flags);
5366 rb->aux_mmap_locked = extra;
5371 atomic_long_add(user_extra, &user->locked_vm);
5372 vma->vm_mm->pinned_vm += extra;
5374 atomic_inc(&event->mmap_count);
5376 atomic_dec(&rb->mmap_count);
5379 mutex_unlock(&event->mmap_mutex);
5382 * Since pinned accounting is per vm we cannot allow fork() to copy our
5385 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5386 vma->vm_ops = &perf_mmap_vmops;
5388 if (event->pmu->event_mapped)
5389 event->pmu->event_mapped(event);
5394 static int perf_fasync(int fd, struct file *filp, int on)
5396 struct inode *inode = file_inode(filp);
5397 struct perf_event *event = filp->private_data;
5401 retval = fasync_helper(fd, filp, on, &event->fasync);
5402 inode_unlock(inode);
5410 static const struct file_operations perf_fops = {
5411 .llseek = no_llseek,
5412 .release = perf_release,
5415 .unlocked_ioctl = perf_ioctl,
5416 .compat_ioctl = perf_compat_ioctl,
5418 .fasync = perf_fasync,
5424 * If there's data, ensure we set the poll() state and publish everything
5425 * to user-space before waking everybody up.
5428 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5430 /* only the parent has fasync state */
5432 event = event->parent;
5433 return &event->fasync;
5436 void perf_event_wakeup(struct perf_event *event)
5438 ring_buffer_wakeup(event);
5440 if (event->pending_kill) {
5441 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5442 event->pending_kill = 0;
5446 static void perf_pending_event(struct irq_work *entry)
5448 struct perf_event *event = container_of(entry,
5449 struct perf_event, pending);
5452 rctx = perf_swevent_get_recursion_context();
5454 * If we 'fail' here, that's OK, it means recursion is already disabled
5455 * and we won't recurse 'further'.
5458 if (event->pending_disable) {
5459 event->pending_disable = 0;
5460 perf_event_disable_local(event);
5463 if (event->pending_wakeup) {
5464 event->pending_wakeup = 0;
5465 perf_event_wakeup(event);
5469 perf_swevent_put_recursion_context(rctx);
5473 * We assume there is only KVM supporting the callbacks.
5474 * Later on, we might change it to a list if there is
5475 * another virtualization implementation supporting the callbacks.
5477 struct perf_guest_info_callbacks *perf_guest_cbs;
5479 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5481 perf_guest_cbs = cbs;
5484 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5486 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5488 perf_guest_cbs = NULL;
5491 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5494 perf_output_sample_regs(struct perf_output_handle *handle,
5495 struct pt_regs *regs, u64 mask)
5498 DECLARE_BITMAP(_mask, 64);
5500 bitmap_from_u64(_mask, mask);
5501 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5504 val = perf_reg_value(regs, bit);
5505 perf_output_put(handle, val);
5509 static void perf_sample_regs_user(struct perf_regs *regs_user,
5510 struct pt_regs *regs,
5511 struct pt_regs *regs_user_copy)
5513 if (user_mode(regs)) {
5514 regs_user->abi = perf_reg_abi(current);
5515 regs_user->regs = regs;
5516 } else if (current->mm) {
5517 perf_get_regs_user(regs_user, regs, regs_user_copy);
5519 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5520 regs_user->regs = NULL;
5524 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5525 struct pt_regs *regs)
5527 regs_intr->regs = regs;
5528 regs_intr->abi = perf_reg_abi(current);
5533 * Get remaining task size from user stack pointer.
5535 * It'd be better to take stack vma map and limit this more
5536 * precisly, but there's no way to get it safely under interrupt,
5537 * so using TASK_SIZE as limit.
5539 static u64 perf_ustack_task_size(struct pt_regs *regs)
5541 unsigned long addr = perf_user_stack_pointer(regs);
5543 if (!addr || addr >= TASK_SIZE)
5546 return TASK_SIZE - addr;
5550 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5551 struct pt_regs *regs)
5555 /* No regs, no stack pointer, no dump. */
5560 * Check if we fit in with the requested stack size into the:
5562 * If we don't, we limit the size to the TASK_SIZE.
5564 * - remaining sample size
5565 * If we don't, we customize the stack size to
5566 * fit in to the remaining sample size.
5569 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5570 stack_size = min(stack_size, (u16) task_size);
5572 /* Current header size plus static size and dynamic size. */
5573 header_size += 2 * sizeof(u64);
5575 /* Do we fit in with the current stack dump size? */
5576 if ((u16) (header_size + stack_size) < header_size) {
5578 * If we overflow the maximum size for the sample,
5579 * we customize the stack dump size to fit in.
5581 stack_size = USHRT_MAX - header_size - sizeof(u64);
5582 stack_size = round_up(stack_size, sizeof(u64));
5589 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5590 struct pt_regs *regs)
5592 /* Case of a kernel thread, nothing to dump */
5595 perf_output_put(handle, size);
5604 * - the size requested by user or the best one we can fit
5605 * in to the sample max size
5607 * - user stack dump data
5609 * - the actual dumped size
5613 perf_output_put(handle, dump_size);
5616 sp = perf_user_stack_pointer(regs);
5617 rem = __output_copy_user(handle, (void *) sp, dump_size);
5618 dyn_size = dump_size - rem;
5620 perf_output_skip(handle, rem);
5623 perf_output_put(handle, dyn_size);
5627 static void __perf_event_header__init_id(struct perf_event_header *header,
5628 struct perf_sample_data *data,
5629 struct perf_event *event)
5631 u64 sample_type = event->attr.sample_type;
5633 data->type = sample_type;
5634 header->size += event->id_header_size;
5636 if (sample_type & PERF_SAMPLE_TID) {
5637 /* namespace issues */
5638 data->tid_entry.pid = perf_event_pid(event, current);
5639 data->tid_entry.tid = perf_event_tid(event, current);
5642 if (sample_type & PERF_SAMPLE_TIME)
5643 data->time = perf_event_clock(event);
5645 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5646 data->id = primary_event_id(event);
5648 if (sample_type & PERF_SAMPLE_STREAM_ID)
5649 data->stream_id = event->id;
5651 if (sample_type & PERF_SAMPLE_CPU) {
5652 data->cpu_entry.cpu = raw_smp_processor_id();
5653 data->cpu_entry.reserved = 0;
5657 void perf_event_header__init_id(struct perf_event_header *header,
5658 struct perf_sample_data *data,
5659 struct perf_event *event)
5661 if (event->attr.sample_id_all)
5662 __perf_event_header__init_id(header, data, event);
5665 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5666 struct perf_sample_data *data)
5668 u64 sample_type = data->type;
5670 if (sample_type & PERF_SAMPLE_TID)
5671 perf_output_put(handle, data->tid_entry);
5673 if (sample_type & PERF_SAMPLE_TIME)
5674 perf_output_put(handle, data->time);
5676 if (sample_type & PERF_SAMPLE_ID)
5677 perf_output_put(handle, data->id);
5679 if (sample_type & PERF_SAMPLE_STREAM_ID)
5680 perf_output_put(handle, data->stream_id);
5682 if (sample_type & PERF_SAMPLE_CPU)
5683 perf_output_put(handle, data->cpu_entry);
5685 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5686 perf_output_put(handle, data->id);
5689 void perf_event__output_id_sample(struct perf_event *event,
5690 struct perf_output_handle *handle,
5691 struct perf_sample_data *sample)
5693 if (event->attr.sample_id_all)
5694 __perf_event__output_id_sample(handle, sample);
5697 static void perf_output_read_one(struct perf_output_handle *handle,
5698 struct perf_event *event,
5699 u64 enabled, u64 running)
5701 u64 read_format = event->attr.read_format;
5705 values[n++] = perf_event_count(event);
5706 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5707 values[n++] = enabled +
5708 atomic64_read(&event->child_total_time_enabled);
5710 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5711 values[n++] = running +
5712 atomic64_read(&event->child_total_time_running);
5714 if (read_format & PERF_FORMAT_ID)
5715 values[n++] = primary_event_id(event);
5717 __output_copy(handle, values, n * sizeof(u64));
5720 static void perf_output_read_group(struct perf_output_handle *handle,
5721 struct perf_event *event,
5722 u64 enabled, u64 running)
5724 struct perf_event *leader = event->group_leader, *sub;
5725 u64 read_format = event->attr.read_format;
5729 values[n++] = 1 + leader->nr_siblings;
5731 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5732 values[n++] = enabled;
5734 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5735 values[n++] = running;
5737 if (leader != event)
5738 leader->pmu->read(leader);
5740 values[n++] = perf_event_count(leader);
5741 if (read_format & PERF_FORMAT_ID)
5742 values[n++] = primary_event_id(leader);
5744 __output_copy(handle, values, n * sizeof(u64));
5746 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5749 if ((sub != event) &&
5750 (sub->state == PERF_EVENT_STATE_ACTIVE))
5751 sub->pmu->read(sub);
5753 values[n++] = perf_event_count(sub);
5754 if (read_format & PERF_FORMAT_ID)
5755 values[n++] = primary_event_id(sub);
5757 __output_copy(handle, values, n * sizeof(u64));
5761 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5762 PERF_FORMAT_TOTAL_TIME_RUNNING)
5765 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5767 * The problem is that its both hard and excessively expensive to iterate the
5768 * child list, not to mention that its impossible to IPI the children running
5769 * on another CPU, from interrupt/NMI context.
5771 static void perf_output_read(struct perf_output_handle *handle,
5772 struct perf_event *event)
5774 u64 enabled = 0, running = 0, now;
5775 u64 read_format = event->attr.read_format;
5778 * compute total_time_enabled, total_time_running
5779 * based on snapshot values taken when the event
5780 * was last scheduled in.
5782 * we cannot simply called update_context_time()
5783 * because of locking issue as we are called in
5786 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5787 calc_timer_values(event, &now, &enabled, &running);
5789 if (event->attr.read_format & PERF_FORMAT_GROUP)
5790 perf_output_read_group(handle, event, enabled, running);
5792 perf_output_read_one(handle, event, enabled, running);
5795 void perf_output_sample(struct perf_output_handle *handle,
5796 struct perf_event_header *header,
5797 struct perf_sample_data *data,
5798 struct perf_event *event)
5800 u64 sample_type = data->type;
5802 perf_output_put(handle, *header);
5804 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5805 perf_output_put(handle, data->id);
5807 if (sample_type & PERF_SAMPLE_IP)
5808 perf_output_put(handle, data->ip);
5810 if (sample_type & PERF_SAMPLE_TID)
5811 perf_output_put(handle, data->tid_entry);
5813 if (sample_type & PERF_SAMPLE_TIME)
5814 perf_output_put(handle, data->time);
5816 if (sample_type & PERF_SAMPLE_ADDR)
5817 perf_output_put(handle, data->addr);
5819 if (sample_type & PERF_SAMPLE_ID)
5820 perf_output_put(handle, data->id);
5822 if (sample_type & PERF_SAMPLE_STREAM_ID)
5823 perf_output_put(handle, data->stream_id);
5825 if (sample_type & PERF_SAMPLE_CPU)
5826 perf_output_put(handle, data->cpu_entry);
5828 if (sample_type & PERF_SAMPLE_PERIOD)
5829 perf_output_put(handle, data->period);
5831 if (sample_type & PERF_SAMPLE_READ)
5832 perf_output_read(handle, event);
5834 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5835 if (data->callchain) {
5838 if (data->callchain)
5839 size += data->callchain->nr;
5841 size *= sizeof(u64);
5843 __output_copy(handle, data->callchain, size);
5846 perf_output_put(handle, nr);
5850 if (sample_type & PERF_SAMPLE_RAW) {
5851 struct perf_raw_record *raw = data->raw;
5854 struct perf_raw_frag *frag = &raw->frag;
5856 perf_output_put(handle, raw->size);
5859 __output_custom(handle, frag->copy,
5860 frag->data, frag->size);
5862 __output_copy(handle, frag->data,
5865 if (perf_raw_frag_last(frag))
5870 __output_skip(handle, NULL, frag->pad);
5876 .size = sizeof(u32),
5879 perf_output_put(handle, raw);
5883 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5884 if (data->br_stack) {
5887 size = data->br_stack->nr
5888 * sizeof(struct perf_branch_entry);
5890 perf_output_put(handle, data->br_stack->nr);
5891 perf_output_copy(handle, data->br_stack->entries, size);
5894 * we always store at least the value of nr
5897 perf_output_put(handle, nr);
5901 if (sample_type & PERF_SAMPLE_REGS_USER) {
5902 u64 abi = data->regs_user.abi;
5905 * If there are no regs to dump, notice it through
5906 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5908 perf_output_put(handle, abi);
5911 u64 mask = event->attr.sample_regs_user;
5912 perf_output_sample_regs(handle,
5913 data->regs_user.regs,
5918 if (sample_type & PERF_SAMPLE_STACK_USER) {
5919 perf_output_sample_ustack(handle,
5920 data->stack_user_size,
5921 data->regs_user.regs);
5924 if (sample_type & PERF_SAMPLE_WEIGHT)
5925 perf_output_put(handle, data->weight);
5927 if (sample_type & PERF_SAMPLE_DATA_SRC)
5928 perf_output_put(handle, data->data_src.val);
5930 if (sample_type & PERF_SAMPLE_TRANSACTION)
5931 perf_output_put(handle, data->txn);
5933 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5934 u64 abi = data->regs_intr.abi;
5936 * If there are no regs to dump, notice it through
5937 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5939 perf_output_put(handle, abi);
5942 u64 mask = event->attr.sample_regs_intr;
5944 perf_output_sample_regs(handle,
5945 data->regs_intr.regs,
5950 if (!event->attr.watermark) {
5951 int wakeup_events = event->attr.wakeup_events;
5953 if (wakeup_events) {
5954 struct ring_buffer *rb = handle->rb;
5955 int events = local_inc_return(&rb->events);
5957 if (events >= wakeup_events) {
5958 local_sub(wakeup_events, &rb->events);
5959 local_inc(&rb->wakeup);
5965 void perf_prepare_sample(struct perf_event_header *header,
5966 struct perf_sample_data *data,
5967 struct perf_event *event,
5968 struct pt_regs *regs)
5970 u64 sample_type = event->attr.sample_type;
5972 header->type = PERF_RECORD_SAMPLE;
5973 header->size = sizeof(*header) + event->header_size;
5976 header->misc |= perf_misc_flags(regs);
5978 __perf_event_header__init_id(header, data, event);
5980 if (sample_type & PERF_SAMPLE_IP)
5981 data->ip = perf_instruction_pointer(regs);
5983 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5986 data->callchain = perf_callchain(event, regs);
5988 if (data->callchain)
5989 size += data->callchain->nr;
5991 header->size += size * sizeof(u64);
5994 if (sample_type & PERF_SAMPLE_RAW) {
5995 struct perf_raw_record *raw = data->raw;
5999 struct perf_raw_frag *frag = &raw->frag;
6004 if (perf_raw_frag_last(frag))
6009 size = round_up(sum + sizeof(u32), sizeof(u64));
6010 raw->size = size - sizeof(u32);
6011 frag->pad = raw->size - sum;
6016 header->size += size;
6019 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6020 int size = sizeof(u64); /* nr */
6021 if (data->br_stack) {
6022 size += data->br_stack->nr
6023 * sizeof(struct perf_branch_entry);
6025 header->size += size;
6028 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6029 perf_sample_regs_user(&data->regs_user, regs,
6030 &data->regs_user_copy);
6032 if (sample_type & PERF_SAMPLE_REGS_USER) {
6033 /* regs dump ABI info */
6034 int size = sizeof(u64);
6036 if (data->regs_user.regs) {
6037 u64 mask = event->attr.sample_regs_user;
6038 size += hweight64(mask) * sizeof(u64);
6041 header->size += size;
6044 if (sample_type & PERF_SAMPLE_STACK_USER) {
6046 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6047 * processed as the last one or have additional check added
6048 * in case new sample type is added, because we could eat
6049 * up the rest of the sample size.
6051 u16 stack_size = event->attr.sample_stack_user;
6052 u16 size = sizeof(u64);
6054 stack_size = perf_sample_ustack_size(stack_size, header->size,
6055 data->regs_user.regs);
6058 * If there is something to dump, add space for the dump
6059 * itself and for the field that tells the dynamic size,
6060 * which is how many have been actually dumped.
6063 size += sizeof(u64) + stack_size;
6065 data->stack_user_size = stack_size;
6066 header->size += size;
6069 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6070 /* regs dump ABI info */
6071 int size = sizeof(u64);
6073 perf_sample_regs_intr(&data->regs_intr, regs);
6075 if (data->regs_intr.regs) {
6076 u64 mask = event->attr.sample_regs_intr;
6078 size += hweight64(mask) * sizeof(u64);
6081 header->size += size;
6085 static void __always_inline
6086 __perf_event_output(struct perf_event *event,
6087 struct perf_sample_data *data,
6088 struct pt_regs *regs,
6089 int (*output_begin)(struct perf_output_handle *,
6090 struct perf_event *,
6093 struct perf_output_handle handle;
6094 struct perf_event_header header;
6096 /* protect the callchain buffers */
6099 perf_prepare_sample(&header, data, event, regs);
6101 if (output_begin(&handle, event, header.size))
6104 perf_output_sample(&handle, &header, data, event);
6106 perf_output_end(&handle);
6113 perf_event_output_forward(struct perf_event *event,
6114 struct perf_sample_data *data,
6115 struct pt_regs *regs)
6117 __perf_event_output(event, data, regs, perf_output_begin_forward);
6121 perf_event_output_backward(struct perf_event *event,
6122 struct perf_sample_data *data,
6123 struct pt_regs *regs)
6125 __perf_event_output(event, data, regs, perf_output_begin_backward);
6129 perf_event_output(struct perf_event *event,
6130 struct perf_sample_data *data,
6131 struct pt_regs *regs)
6133 __perf_event_output(event, data, regs, perf_output_begin);
6140 struct perf_read_event {
6141 struct perf_event_header header;
6148 perf_event_read_event(struct perf_event *event,
6149 struct task_struct *task)
6151 struct perf_output_handle handle;
6152 struct perf_sample_data sample;
6153 struct perf_read_event read_event = {
6155 .type = PERF_RECORD_READ,
6157 .size = sizeof(read_event) + event->read_size,
6159 .pid = perf_event_pid(event, task),
6160 .tid = perf_event_tid(event, task),
6164 perf_event_header__init_id(&read_event.header, &sample, event);
6165 ret = perf_output_begin(&handle, event, read_event.header.size);
6169 perf_output_put(&handle, read_event);
6170 perf_output_read(&handle, event);
6171 perf_event__output_id_sample(event, &handle, &sample);
6173 perf_output_end(&handle);
6176 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6179 perf_iterate_ctx(struct perf_event_context *ctx,
6180 perf_iterate_f output,
6181 void *data, bool all)
6183 struct perf_event *event;
6185 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6187 if (event->state < PERF_EVENT_STATE_INACTIVE)
6189 if (!event_filter_match(event))
6193 output(event, data);
6197 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6199 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6200 struct perf_event *event;
6202 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6204 * Skip events that are not fully formed yet; ensure that
6205 * if we observe event->ctx, both event and ctx will be
6206 * complete enough. See perf_install_in_context().
6208 if (!smp_load_acquire(&event->ctx))
6211 if (event->state < PERF_EVENT_STATE_INACTIVE)
6213 if (!event_filter_match(event))
6215 output(event, data);
6220 * Iterate all events that need to receive side-band events.
6222 * For new callers; ensure that account_pmu_sb_event() includes
6223 * your event, otherwise it might not get delivered.
6226 perf_iterate_sb(perf_iterate_f output, void *data,
6227 struct perf_event_context *task_ctx)
6229 struct perf_event_context *ctx;
6236 * If we have task_ctx != NULL we only notify the task context itself.
6237 * The task_ctx is set only for EXIT events before releasing task
6241 perf_iterate_ctx(task_ctx, output, data, false);
6245 perf_iterate_sb_cpu(output, data);
6247 for_each_task_context_nr(ctxn) {
6248 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6250 perf_iterate_ctx(ctx, output, data, false);
6258 * Clear all file-based filters at exec, they'll have to be
6259 * re-instated when/if these objects are mmapped again.
6261 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6263 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6264 struct perf_addr_filter *filter;
6265 unsigned int restart = 0, count = 0;
6266 unsigned long flags;
6268 if (!has_addr_filter(event))
6271 raw_spin_lock_irqsave(&ifh->lock, flags);
6272 list_for_each_entry(filter, &ifh->list, entry) {
6273 if (filter->inode) {
6274 event->addr_filters_offs[count] = 0;
6282 event->addr_filters_gen++;
6283 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6286 perf_event_stop(event, 1);
6289 void perf_event_exec(void)
6291 struct perf_event_context *ctx;
6295 for_each_task_context_nr(ctxn) {
6296 ctx = current->perf_event_ctxp[ctxn];
6300 perf_event_enable_on_exec(ctxn);
6302 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6308 struct remote_output {
6309 struct ring_buffer *rb;
6313 static void __perf_event_output_stop(struct perf_event *event, void *data)
6315 struct perf_event *parent = event->parent;
6316 struct remote_output *ro = data;
6317 struct ring_buffer *rb = ro->rb;
6318 struct stop_event_data sd = {
6322 if (!has_aux(event))
6329 * In case of inheritance, it will be the parent that links to the
6330 * ring-buffer, but it will be the child that's actually using it.
6332 * We are using event::rb to determine if the event should be stopped,
6333 * however this may race with ring_buffer_attach() (through set_output),
6334 * which will make us skip the event that actually needs to be stopped.
6335 * So ring_buffer_attach() has to stop an aux event before re-assigning
6338 if (rcu_dereference(parent->rb) == rb)
6339 ro->err = __perf_event_stop(&sd);
6342 static int __perf_pmu_output_stop(void *info)
6344 struct perf_event *event = info;
6345 struct pmu *pmu = event->pmu;
6346 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6347 struct remote_output ro = {
6352 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6353 if (cpuctx->task_ctx)
6354 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6361 static void perf_pmu_output_stop(struct perf_event *event)
6363 struct perf_event *iter;
6368 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6370 * For per-CPU events, we need to make sure that neither they
6371 * nor their children are running; for cpu==-1 events it's
6372 * sufficient to stop the event itself if it's active, since
6373 * it can't have children.
6377 cpu = READ_ONCE(iter->oncpu);
6382 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6383 if (err == -EAGAIN) {
6392 * task tracking -- fork/exit
6394 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6397 struct perf_task_event {
6398 struct task_struct *task;
6399 struct perf_event_context *task_ctx;
6402 struct perf_event_header header;
6412 static int perf_event_task_match(struct perf_event *event)
6414 return event->attr.comm || event->attr.mmap ||
6415 event->attr.mmap2 || event->attr.mmap_data ||
6419 static void perf_event_task_output(struct perf_event *event,
6422 struct perf_task_event *task_event = data;
6423 struct perf_output_handle handle;
6424 struct perf_sample_data sample;
6425 struct task_struct *task = task_event->task;
6426 int ret, size = task_event->event_id.header.size;
6428 if (!perf_event_task_match(event))
6431 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6433 ret = perf_output_begin(&handle, event,
6434 task_event->event_id.header.size);
6438 task_event->event_id.pid = perf_event_pid(event, task);
6439 task_event->event_id.ppid = perf_event_pid(event, current);
6441 task_event->event_id.tid = perf_event_tid(event, task);
6442 task_event->event_id.ptid = perf_event_tid(event, current);
6444 task_event->event_id.time = perf_event_clock(event);
6446 perf_output_put(&handle, task_event->event_id);
6448 perf_event__output_id_sample(event, &handle, &sample);
6450 perf_output_end(&handle);
6452 task_event->event_id.header.size = size;
6455 static void perf_event_task(struct task_struct *task,
6456 struct perf_event_context *task_ctx,
6459 struct perf_task_event task_event;
6461 if (!atomic_read(&nr_comm_events) &&
6462 !atomic_read(&nr_mmap_events) &&
6463 !atomic_read(&nr_task_events))
6466 task_event = (struct perf_task_event){
6468 .task_ctx = task_ctx,
6471 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6473 .size = sizeof(task_event.event_id),
6483 perf_iterate_sb(perf_event_task_output,
6488 void perf_event_fork(struct task_struct *task)
6490 perf_event_task(task, NULL, 1);
6491 perf_event_namespaces(task);
6498 struct perf_comm_event {
6499 struct task_struct *task;
6504 struct perf_event_header header;
6511 static int perf_event_comm_match(struct perf_event *event)
6513 return event->attr.comm;
6516 static void perf_event_comm_output(struct perf_event *event,
6519 struct perf_comm_event *comm_event = data;
6520 struct perf_output_handle handle;
6521 struct perf_sample_data sample;
6522 int size = comm_event->event_id.header.size;
6525 if (!perf_event_comm_match(event))
6528 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6529 ret = perf_output_begin(&handle, event,
6530 comm_event->event_id.header.size);
6535 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6536 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6538 perf_output_put(&handle, comm_event->event_id);
6539 __output_copy(&handle, comm_event->comm,
6540 comm_event->comm_size);
6542 perf_event__output_id_sample(event, &handle, &sample);
6544 perf_output_end(&handle);
6546 comm_event->event_id.header.size = size;
6549 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6551 char comm[TASK_COMM_LEN];
6554 memset(comm, 0, sizeof(comm));
6555 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6556 size = ALIGN(strlen(comm)+1, sizeof(u64));
6558 comm_event->comm = comm;
6559 comm_event->comm_size = size;
6561 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6563 perf_iterate_sb(perf_event_comm_output,
6568 void perf_event_comm(struct task_struct *task, bool exec)
6570 struct perf_comm_event comm_event;
6572 if (!atomic_read(&nr_comm_events))
6575 comm_event = (struct perf_comm_event){
6581 .type = PERF_RECORD_COMM,
6582 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6590 perf_event_comm_event(&comm_event);
6594 * namespaces tracking
6597 struct perf_namespaces_event {
6598 struct task_struct *task;
6601 struct perf_event_header header;
6606 struct perf_ns_link_info link_info[NR_NAMESPACES];
6610 static int perf_event_namespaces_match(struct perf_event *event)
6612 return event->attr.namespaces;
6615 static void perf_event_namespaces_output(struct perf_event *event,
6618 struct perf_namespaces_event *namespaces_event = data;
6619 struct perf_output_handle handle;
6620 struct perf_sample_data sample;
6623 if (!perf_event_namespaces_match(event))
6626 perf_event_header__init_id(&namespaces_event->event_id.header,
6628 ret = perf_output_begin(&handle, event,
6629 namespaces_event->event_id.header.size);
6633 namespaces_event->event_id.pid = perf_event_pid(event,
6634 namespaces_event->task);
6635 namespaces_event->event_id.tid = perf_event_tid(event,
6636 namespaces_event->task);
6638 perf_output_put(&handle, namespaces_event->event_id);
6640 perf_event__output_id_sample(event, &handle, &sample);
6642 perf_output_end(&handle);
6645 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6646 struct task_struct *task,
6647 const struct proc_ns_operations *ns_ops)
6649 struct path ns_path;
6650 struct inode *ns_inode;
6653 error = ns_get_path(&ns_path, task, ns_ops);
6655 ns_inode = ns_path.dentry->d_inode;
6656 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6657 ns_link_info->ino = ns_inode->i_ino;
6661 void perf_event_namespaces(struct task_struct *task)
6663 struct perf_namespaces_event namespaces_event;
6664 struct perf_ns_link_info *ns_link_info;
6666 if (!atomic_read(&nr_namespaces_events))
6669 namespaces_event = (struct perf_namespaces_event){
6673 .type = PERF_RECORD_NAMESPACES,
6675 .size = sizeof(namespaces_event.event_id),
6679 .nr_namespaces = NR_NAMESPACES,
6680 /* .link_info[NR_NAMESPACES] */
6684 ns_link_info = namespaces_event.event_id.link_info;
6686 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6687 task, &mntns_operations);
6689 #ifdef CONFIG_USER_NS
6690 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6691 task, &userns_operations);
6693 #ifdef CONFIG_NET_NS
6694 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6695 task, &netns_operations);
6697 #ifdef CONFIG_UTS_NS
6698 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6699 task, &utsns_operations);
6701 #ifdef CONFIG_IPC_NS
6702 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6703 task, &ipcns_operations);
6705 #ifdef CONFIG_PID_NS
6706 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6707 task, &pidns_operations);
6709 #ifdef CONFIG_CGROUPS
6710 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6711 task, &cgroupns_operations);
6714 perf_iterate_sb(perf_event_namespaces_output,
6723 struct perf_mmap_event {
6724 struct vm_area_struct *vma;
6726 const char *file_name;
6734 struct perf_event_header header;
6744 static int perf_event_mmap_match(struct perf_event *event,
6747 struct perf_mmap_event *mmap_event = data;
6748 struct vm_area_struct *vma = mmap_event->vma;
6749 int executable = vma->vm_flags & VM_EXEC;
6751 return (!executable && event->attr.mmap_data) ||
6752 (executable && (event->attr.mmap || event->attr.mmap2));
6755 static void perf_event_mmap_output(struct perf_event *event,
6758 struct perf_mmap_event *mmap_event = data;
6759 struct perf_output_handle handle;
6760 struct perf_sample_data sample;
6761 int size = mmap_event->event_id.header.size;
6764 if (!perf_event_mmap_match(event, data))
6767 if (event->attr.mmap2) {
6768 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6769 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6770 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6771 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6772 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6773 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6774 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6777 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6778 ret = perf_output_begin(&handle, event,
6779 mmap_event->event_id.header.size);
6783 mmap_event->event_id.pid = perf_event_pid(event, current);
6784 mmap_event->event_id.tid = perf_event_tid(event, current);
6786 perf_output_put(&handle, mmap_event->event_id);
6788 if (event->attr.mmap2) {
6789 perf_output_put(&handle, mmap_event->maj);
6790 perf_output_put(&handle, mmap_event->min);
6791 perf_output_put(&handle, mmap_event->ino);
6792 perf_output_put(&handle, mmap_event->ino_generation);
6793 perf_output_put(&handle, mmap_event->prot);
6794 perf_output_put(&handle, mmap_event->flags);
6797 __output_copy(&handle, mmap_event->file_name,
6798 mmap_event->file_size);
6800 perf_event__output_id_sample(event, &handle, &sample);
6802 perf_output_end(&handle);
6804 mmap_event->event_id.header.size = size;
6807 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6809 struct vm_area_struct *vma = mmap_event->vma;
6810 struct file *file = vma->vm_file;
6811 int maj = 0, min = 0;
6812 u64 ino = 0, gen = 0;
6813 u32 prot = 0, flags = 0;
6819 if (vma->vm_flags & VM_READ)
6821 if (vma->vm_flags & VM_WRITE)
6823 if (vma->vm_flags & VM_EXEC)
6826 if (vma->vm_flags & VM_MAYSHARE)
6829 flags = MAP_PRIVATE;
6831 if (vma->vm_flags & VM_DENYWRITE)
6832 flags |= MAP_DENYWRITE;
6833 if (vma->vm_flags & VM_MAYEXEC)
6834 flags |= MAP_EXECUTABLE;
6835 if (vma->vm_flags & VM_LOCKED)
6836 flags |= MAP_LOCKED;
6837 if (vma->vm_flags & VM_HUGETLB)
6838 flags |= MAP_HUGETLB;
6841 struct inode *inode;
6844 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6850 * d_path() works from the end of the rb backwards, so we
6851 * need to add enough zero bytes after the string to handle
6852 * the 64bit alignment we do later.
6854 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6859 inode = file_inode(vma->vm_file);
6860 dev = inode->i_sb->s_dev;
6862 gen = inode->i_generation;
6868 if (vma->vm_ops && vma->vm_ops->name) {
6869 name = (char *) vma->vm_ops->name(vma);
6874 name = (char *)arch_vma_name(vma);
6878 if (vma->vm_start <= vma->vm_mm->start_brk &&
6879 vma->vm_end >= vma->vm_mm->brk) {
6883 if (vma->vm_start <= vma->vm_mm->start_stack &&
6884 vma->vm_end >= vma->vm_mm->start_stack) {
6894 strlcpy(tmp, name, sizeof(tmp));
6898 * Since our buffer works in 8 byte units we need to align our string
6899 * size to a multiple of 8. However, we must guarantee the tail end is
6900 * zero'd out to avoid leaking random bits to userspace.
6902 size = strlen(name)+1;
6903 while (!IS_ALIGNED(size, sizeof(u64)))
6904 name[size++] = '\0';
6906 mmap_event->file_name = name;
6907 mmap_event->file_size = size;
6908 mmap_event->maj = maj;
6909 mmap_event->min = min;
6910 mmap_event->ino = ino;
6911 mmap_event->ino_generation = gen;
6912 mmap_event->prot = prot;
6913 mmap_event->flags = flags;
6915 if (!(vma->vm_flags & VM_EXEC))
6916 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6918 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6920 perf_iterate_sb(perf_event_mmap_output,
6928 * Check whether inode and address range match filter criteria.
6930 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6931 struct file *file, unsigned long offset,
6934 if (filter->inode != file_inode(file))
6937 if (filter->offset > offset + size)
6940 if (filter->offset + filter->size < offset)
6946 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6948 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6949 struct vm_area_struct *vma = data;
6950 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6951 struct file *file = vma->vm_file;
6952 struct perf_addr_filter *filter;
6953 unsigned int restart = 0, count = 0;
6955 if (!has_addr_filter(event))
6961 raw_spin_lock_irqsave(&ifh->lock, flags);
6962 list_for_each_entry(filter, &ifh->list, entry) {
6963 if (perf_addr_filter_match(filter, file, off,
6964 vma->vm_end - vma->vm_start)) {
6965 event->addr_filters_offs[count] = vma->vm_start;
6973 event->addr_filters_gen++;
6974 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6977 perf_event_stop(event, 1);
6981 * Adjust all task's events' filters to the new vma
6983 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6985 struct perf_event_context *ctx;
6989 * Data tracing isn't supported yet and as such there is no need
6990 * to keep track of anything that isn't related to executable code:
6992 if (!(vma->vm_flags & VM_EXEC))
6996 for_each_task_context_nr(ctxn) {
6997 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7001 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7006 void perf_event_mmap(struct vm_area_struct *vma)
7008 struct perf_mmap_event mmap_event;
7010 if (!atomic_read(&nr_mmap_events))
7013 mmap_event = (struct perf_mmap_event){
7019 .type = PERF_RECORD_MMAP,
7020 .misc = PERF_RECORD_MISC_USER,
7025 .start = vma->vm_start,
7026 .len = vma->vm_end - vma->vm_start,
7027 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7029 /* .maj (attr_mmap2 only) */
7030 /* .min (attr_mmap2 only) */
7031 /* .ino (attr_mmap2 only) */
7032 /* .ino_generation (attr_mmap2 only) */
7033 /* .prot (attr_mmap2 only) */
7034 /* .flags (attr_mmap2 only) */
7037 perf_addr_filters_adjust(vma);
7038 perf_event_mmap_event(&mmap_event);
7041 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7042 unsigned long size, u64 flags)
7044 struct perf_output_handle handle;
7045 struct perf_sample_data sample;
7046 struct perf_aux_event {
7047 struct perf_event_header header;
7053 .type = PERF_RECORD_AUX,
7055 .size = sizeof(rec),
7063 perf_event_header__init_id(&rec.header, &sample, event);
7064 ret = perf_output_begin(&handle, event, rec.header.size);
7069 perf_output_put(&handle, rec);
7070 perf_event__output_id_sample(event, &handle, &sample);
7072 perf_output_end(&handle);
7076 * Lost/dropped samples logging
7078 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7080 struct perf_output_handle handle;
7081 struct perf_sample_data sample;
7085 struct perf_event_header header;
7087 } lost_samples_event = {
7089 .type = PERF_RECORD_LOST_SAMPLES,
7091 .size = sizeof(lost_samples_event),
7096 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7098 ret = perf_output_begin(&handle, event,
7099 lost_samples_event.header.size);
7103 perf_output_put(&handle, lost_samples_event);
7104 perf_event__output_id_sample(event, &handle, &sample);
7105 perf_output_end(&handle);
7109 * context_switch tracking
7112 struct perf_switch_event {
7113 struct task_struct *task;
7114 struct task_struct *next_prev;
7117 struct perf_event_header header;
7123 static int perf_event_switch_match(struct perf_event *event)
7125 return event->attr.context_switch;
7128 static void perf_event_switch_output(struct perf_event *event, void *data)
7130 struct perf_switch_event *se = data;
7131 struct perf_output_handle handle;
7132 struct perf_sample_data sample;
7135 if (!perf_event_switch_match(event))
7138 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7139 if (event->ctx->task) {
7140 se->event_id.header.type = PERF_RECORD_SWITCH;
7141 se->event_id.header.size = sizeof(se->event_id.header);
7143 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7144 se->event_id.header.size = sizeof(se->event_id);
7145 se->event_id.next_prev_pid =
7146 perf_event_pid(event, se->next_prev);
7147 se->event_id.next_prev_tid =
7148 perf_event_tid(event, se->next_prev);
7151 perf_event_header__init_id(&se->event_id.header, &sample, event);
7153 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7157 if (event->ctx->task)
7158 perf_output_put(&handle, se->event_id.header);
7160 perf_output_put(&handle, se->event_id);
7162 perf_event__output_id_sample(event, &handle, &sample);
7164 perf_output_end(&handle);
7167 static void perf_event_switch(struct task_struct *task,
7168 struct task_struct *next_prev, bool sched_in)
7170 struct perf_switch_event switch_event;
7172 /* N.B. caller checks nr_switch_events != 0 */
7174 switch_event = (struct perf_switch_event){
7176 .next_prev = next_prev,
7180 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7183 /* .next_prev_pid */
7184 /* .next_prev_tid */
7188 perf_iterate_sb(perf_event_switch_output,
7194 * IRQ throttle logging
7197 static void perf_log_throttle(struct perf_event *event, int enable)
7199 struct perf_output_handle handle;
7200 struct perf_sample_data sample;
7204 struct perf_event_header header;
7208 } throttle_event = {
7210 .type = PERF_RECORD_THROTTLE,
7212 .size = sizeof(throttle_event),
7214 .time = perf_event_clock(event),
7215 .id = primary_event_id(event),
7216 .stream_id = event->id,
7220 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7222 perf_event_header__init_id(&throttle_event.header, &sample, event);
7224 ret = perf_output_begin(&handle, event,
7225 throttle_event.header.size);
7229 perf_output_put(&handle, throttle_event);
7230 perf_event__output_id_sample(event, &handle, &sample);
7231 perf_output_end(&handle);
7234 static void perf_log_itrace_start(struct perf_event *event)
7236 struct perf_output_handle handle;
7237 struct perf_sample_data sample;
7238 struct perf_aux_event {
7239 struct perf_event_header header;
7246 event = event->parent;
7248 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7249 event->hw.itrace_started)
7252 rec.header.type = PERF_RECORD_ITRACE_START;
7253 rec.header.misc = 0;
7254 rec.header.size = sizeof(rec);
7255 rec.pid = perf_event_pid(event, current);
7256 rec.tid = perf_event_tid(event, current);
7258 perf_event_header__init_id(&rec.header, &sample, event);
7259 ret = perf_output_begin(&handle, event, rec.header.size);
7264 perf_output_put(&handle, rec);
7265 perf_event__output_id_sample(event, &handle, &sample);
7267 perf_output_end(&handle);
7271 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7273 struct hw_perf_event *hwc = &event->hw;
7277 seq = __this_cpu_read(perf_throttled_seq);
7278 if (seq != hwc->interrupts_seq) {
7279 hwc->interrupts_seq = seq;
7280 hwc->interrupts = 1;
7283 if (unlikely(throttle
7284 && hwc->interrupts >= max_samples_per_tick)) {
7285 __this_cpu_inc(perf_throttled_count);
7286 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7287 hwc->interrupts = MAX_INTERRUPTS;
7288 perf_log_throttle(event, 0);
7293 if (event->attr.freq) {
7294 u64 now = perf_clock();
7295 s64 delta = now - hwc->freq_time_stamp;
7297 hwc->freq_time_stamp = now;
7299 if (delta > 0 && delta < 2*TICK_NSEC)
7300 perf_adjust_period(event, delta, hwc->last_period, true);
7306 int perf_event_account_interrupt(struct perf_event *event)
7308 return __perf_event_account_interrupt(event, 1);
7312 * Generic event overflow handling, sampling.
7315 static int __perf_event_overflow(struct perf_event *event,
7316 int throttle, struct perf_sample_data *data,
7317 struct pt_regs *regs)
7319 int events = atomic_read(&event->event_limit);
7323 * Non-sampling counters might still use the PMI to fold short
7324 * hardware counters, ignore those.
7326 if (unlikely(!is_sampling_event(event)))
7329 ret = __perf_event_account_interrupt(event, throttle);
7332 * XXX event_limit might not quite work as expected on inherited
7336 event->pending_kill = POLL_IN;
7337 if (events && atomic_dec_and_test(&event->event_limit)) {
7339 event->pending_kill = POLL_HUP;
7341 perf_event_disable_inatomic(event);
7344 READ_ONCE(event->overflow_handler)(event, data, regs);
7346 if (*perf_event_fasync(event) && event->pending_kill) {
7347 event->pending_wakeup = 1;
7348 irq_work_queue(&event->pending);
7354 int perf_event_overflow(struct perf_event *event,
7355 struct perf_sample_data *data,
7356 struct pt_regs *regs)
7358 return __perf_event_overflow(event, 1, data, regs);
7362 * Generic software event infrastructure
7365 struct swevent_htable {
7366 struct swevent_hlist *swevent_hlist;
7367 struct mutex hlist_mutex;
7370 /* Recursion avoidance in each contexts */
7371 int recursion[PERF_NR_CONTEXTS];
7374 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7377 * We directly increment event->count and keep a second value in
7378 * event->hw.period_left to count intervals. This period event
7379 * is kept in the range [-sample_period, 0] so that we can use the
7383 u64 perf_swevent_set_period(struct perf_event *event)
7385 struct hw_perf_event *hwc = &event->hw;
7386 u64 period = hwc->last_period;
7390 hwc->last_period = hwc->sample_period;
7393 old = val = local64_read(&hwc->period_left);
7397 nr = div64_u64(period + val, period);
7398 offset = nr * period;
7400 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7406 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7407 struct perf_sample_data *data,
7408 struct pt_regs *regs)
7410 struct hw_perf_event *hwc = &event->hw;
7414 overflow = perf_swevent_set_period(event);
7416 if (hwc->interrupts == MAX_INTERRUPTS)
7419 for (; overflow; overflow--) {
7420 if (__perf_event_overflow(event, throttle,
7423 * We inhibit the overflow from happening when
7424 * hwc->interrupts == MAX_INTERRUPTS.
7432 static void perf_swevent_event(struct perf_event *event, u64 nr,
7433 struct perf_sample_data *data,
7434 struct pt_regs *regs)
7436 struct hw_perf_event *hwc = &event->hw;
7438 local64_add(nr, &event->count);
7443 if (!is_sampling_event(event))
7446 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7448 return perf_swevent_overflow(event, 1, data, regs);
7450 data->period = event->hw.last_period;
7452 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7453 return perf_swevent_overflow(event, 1, data, regs);
7455 if (local64_add_negative(nr, &hwc->period_left))
7458 perf_swevent_overflow(event, 0, data, regs);
7461 static int perf_exclude_event(struct perf_event *event,
7462 struct pt_regs *regs)
7464 if (event->hw.state & PERF_HES_STOPPED)
7468 if (event->attr.exclude_user && user_mode(regs))
7471 if (event->attr.exclude_kernel && !user_mode(regs))
7478 static int perf_swevent_match(struct perf_event *event,
7479 enum perf_type_id type,
7481 struct perf_sample_data *data,
7482 struct pt_regs *regs)
7484 if (event->attr.type != type)
7487 if (event->attr.config != event_id)
7490 if (perf_exclude_event(event, regs))
7496 static inline u64 swevent_hash(u64 type, u32 event_id)
7498 u64 val = event_id | (type << 32);
7500 return hash_64(val, SWEVENT_HLIST_BITS);
7503 static inline struct hlist_head *
7504 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7506 u64 hash = swevent_hash(type, event_id);
7508 return &hlist->heads[hash];
7511 /* For the read side: events when they trigger */
7512 static inline struct hlist_head *
7513 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7515 struct swevent_hlist *hlist;
7517 hlist = rcu_dereference(swhash->swevent_hlist);
7521 return __find_swevent_head(hlist, type, event_id);
7524 /* For the event head insertion and removal in the hlist */
7525 static inline struct hlist_head *
7526 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7528 struct swevent_hlist *hlist;
7529 u32 event_id = event->attr.config;
7530 u64 type = event->attr.type;
7533 * Event scheduling is always serialized against hlist allocation
7534 * and release. Which makes the protected version suitable here.
7535 * The context lock guarantees that.
7537 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7538 lockdep_is_held(&event->ctx->lock));
7542 return __find_swevent_head(hlist, type, event_id);
7545 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7547 struct perf_sample_data *data,
7548 struct pt_regs *regs)
7550 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7551 struct perf_event *event;
7552 struct hlist_head *head;
7555 head = find_swevent_head_rcu(swhash, type, event_id);
7559 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7560 if (perf_swevent_match(event, type, event_id, data, regs))
7561 perf_swevent_event(event, nr, data, regs);
7567 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7569 int perf_swevent_get_recursion_context(void)
7571 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7573 return get_recursion_context(swhash->recursion);
7575 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7577 void perf_swevent_put_recursion_context(int rctx)
7579 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7581 put_recursion_context(swhash->recursion, rctx);
7584 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7586 struct perf_sample_data data;
7588 if (WARN_ON_ONCE(!regs))
7591 perf_sample_data_init(&data, addr, 0);
7592 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7595 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7599 preempt_disable_notrace();
7600 rctx = perf_swevent_get_recursion_context();
7601 if (unlikely(rctx < 0))
7604 ___perf_sw_event(event_id, nr, regs, addr);
7606 perf_swevent_put_recursion_context(rctx);
7608 preempt_enable_notrace();
7611 static void perf_swevent_read(struct perf_event *event)
7615 static int perf_swevent_add(struct perf_event *event, int flags)
7617 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7618 struct hw_perf_event *hwc = &event->hw;
7619 struct hlist_head *head;
7621 if (is_sampling_event(event)) {
7622 hwc->last_period = hwc->sample_period;
7623 perf_swevent_set_period(event);
7626 hwc->state = !(flags & PERF_EF_START);
7628 head = find_swevent_head(swhash, event);
7629 if (WARN_ON_ONCE(!head))
7632 hlist_add_head_rcu(&event->hlist_entry, head);
7633 perf_event_update_userpage(event);
7638 static void perf_swevent_del(struct perf_event *event, int flags)
7640 hlist_del_rcu(&event->hlist_entry);
7643 static void perf_swevent_start(struct perf_event *event, int flags)
7645 event->hw.state = 0;
7648 static void perf_swevent_stop(struct perf_event *event, int flags)
7650 event->hw.state = PERF_HES_STOPPED;
7653 /* Deref the hlist from the update side */
7654 static inline struct swevent_hlist *
7655 swevent_hlist_deref(struct swevent_htable *swhash)
7657 return rcu_dereference_protected(swhash->swevent_hlist,
7658 lockdep_is_held(&swhash->hlist_mutex));
7661 static void swevent_hlist_release(struct swevent_htable *swhash)
7663 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7668 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7669 kfree_rcu(hlist, rcu_head);
7672 static void swevent_hlist_put_cpu(int cpu)
7674 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7676 mutex_lock(&swhash->hlist_mutex);
7678 if (!--swhash->hlist_refcount)
7679 swevent_hlist_release(swhash);
7681 mutex_unlock(&swhash->hlist_mutex);
7684 static void swevent_hlist_put(void)
7688 for_each_possible_cpu(cpu)
7689 swevent_hlist_put_cpu(cpu);
7692 static int swevent_hlist_get_cpu(int cpu)
7694 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7697 mutex_lock(&swhash->hlist_mutex);
7698 if (!swevent_hlist_deref(swhash) &&
7699 cpumask_test_cpu(cpu, perf_online_mask)) {
7700 struct swevent_hlist *hlist;
7702 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7707 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7709 swhash->hlist_refcount++;
7711 mutex_unlock(&swhash->hlist_mutex);
7716 static int swevent_hlist_get(void)
7718 int err, cpu, failed_cpu;
7720 mutex_lock(&pmus_lock);
7721 for_each_possible_cpu(cpu) {
7722 err = swevent_hlist_get_cpu(cpu);
7728 mutex_unlock(&pmus_lock);
7731 for_each_possible_cpu(cpu) {
7732 if (cpu == failed_cpu)
7734 swevent_hlist_put_cpu(cpu);
7736 mutex_unlock(&pmus_lock);
7740 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7742 static void sw_perf_event_destroy(struct perf_event *event)
7744 u64 event_id = event->attr.config;
7746 WARN_ON(event->parent);
7748 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7749 swevent_hlist_put();
7752 static int perf_swevent_init(struct perf_event *event)
7754 u64 event_id = event->attr.config;
7756 if (event->attr.type != PERF_TYPE_SOFTWARE)
7760 * no branch sampling for software events
7762 if (has_branch_stack(event))
7766 case PERF_COUNT_SW_CPU_CLOCK:
7767 case PERF_COUNT_SW_TASK_CLOCK:
7774 if (event_id >= PERF_COUNT_SW_MAX)
7777 if (!event->parent) {
7780 err = swevent_hlist_get();
7784 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7785 event->destroy = sw_perf_event_destroy;
7791 static struct pmu perf_swevent = {
7792 .task_ctx_nr = perf_sw_context,
7794 .capabilities = PERF_PMU_CAP_NO_NMI,
7796 .event_init = perf_swevent_init,
7797 .add = perf_swevent_add,
7798 .del = perf_swevent_del,
7799 .start = perf_swevent_start,
7800 .stop = perf_swevent_stop,
7801 .read = perf_swevent_read,
7804 #ifdef CONFIG_EVENT_TRACING
7806 static int perf_tp_filter_match(struct perf_event *event,
7807 struct perf_sample_data *data)
7809 void *record = data->raw->frag.data;
7811 /* only top level events have filters set */
7813 event = event->parent;
7815 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7820 static int perf_tp_event_match(struct perf_event *event,
7821 struct perf_sample_data *data,
7822 struct pt_regs *regs)
7824 if (event->hw.state & PERF_HES_STOPPED)
7827 * All tracepoints are from kernel-space.
7829 if (event->attr.exclude_kernel)
7832 if (!perf_tp_filter_match(event, data))
7838 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7839 struct trace_event_call *call, u64 count,
7840 struct pt_regs *regs, struct hlist_head *head,
7841 struct task_struct *task)
7843 struct bpf_prog *prog = call->prog;
7846 *(struct pt_regs **)raw_data = regs;
7847 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7848 perf_swevent_put_recursion_context(rctx);
7852 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7855 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7857 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7858 struct pt_regs *regs, struct hlist_head *head, int rctx,
7859 struct task_struct *task)
7861 struct perf_sample_data data;
7862 struct perf_event *event;
7864 struct perf_raw_record raw = {
7871 perf_sample_data_init(&data, 0, 0);
7874 perf_trace_buf_update(record, event_type);
7876 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7877 if (perf_tp_event_match(event, &data, regs))
7878 perf_swevent_event(event, count, &data, regs);
7882 * If we got specified a target task, also iterate its context and
7883 * deliver this event there too.
7885 if (task && task != current) {
7886 struct perf_event_context *ctx;
7887 struct trace_entry *entry = record;
7890 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7894 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7895 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7897 if (event->attr.config != entry->type)
7899 if (perf_tp_event_match(event, &data, regs))
7900 perf_swevent_event(event, count, &data, regs);
7906 perf_swevent_put_recursion_context(rctx);
7908 EXPORT_SYMBOL_GPL(perf_tp_event);
7910 static void tp_perf_event_destroy(struct perf_event *event)
7912 perf_trace_destroy(event);
7915 static int perf_tp_event_init(struct perf_event *event)
7919 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7923 * no branch sampling for tracepoint events
7925 if (has_branch_stack(event))
7928 err = perf_trace_init(event);
7932 event->destroy = tp_perf_event_destroy;
7937 static struct pmu perf_tracepoint = {
7938 .task_ctx_nr = perf_sw_context,
7940 .event_init = perf_tp_event_init,
7941 .add = perf_trace_add,
7942 .del = perf_trace_del,
7943 .start = perf_swevent_start,
7944 .stop = perf_swevent_stop,
7945 .read = perf_swevent_read,
7948 static inline void perf_tp_register(void)
7950 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7953 static void perf_event_free_filter(struct perf_event *event)
7955 ftrace_profile_free_filter(event);
7958 #ifdef CONFIG_BPF_SYSCALL
7959 static void bpf_overflow_handler(struct perf_event *event,
7960 struct perf_sample_data *data,
7961 struct pt_regs *regs)
7963 struct bpf_perf_event_data_kern ctx = {
7970 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7973 ret = BPF_PROG_RUN(event->prog, &ctx);
7976 __this_cpu_dec(bpf_prog_active);
7981 event->orig_overflow_handler(event, data, regs);
7984 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7986 struct bpf_prog *prog;
7988 if (event->overflow_handler_context)
7989 /* hw breakpoint or kernel counter */
7995 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
7997 return PTR_ERR(prog);
8000 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8001 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8005 static void perf_event_free_bpf_handler(struct perf_event *event)
8007 struct bpf_prog *prog = event->prog;
8012 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8017 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8021 static void perf_event_free_bpf_handler(struct perf_event *event)
8026 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8028 bool is_kprobe, is_tracepoint;
8029 struct bpf_prog *prog;
8031 if (event->attr.type == PERF_TYPE_HARDWARE ||
8032 event->attr.type == PERF_TYPE_SOFTWARE)
8033 return perf_event_set_bpf_handler(event, prog_fd);
8035 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8038 if (event->tp_event->prog)
8041 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8042 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8043 if (!is_kprobe && !is_tracepoint)
8044 /* bpf programs can only be attached to u/kprobe or tracepoint */
8047 prog = bpf_prog_get(prog_fd);
8049 return PTR_ERR(prog);
8051 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8052 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8053 /* valid fd, but invalid bpf program type */
8058 if (is_tracepoint) {
8059 int off = trace_event_get_offsets(event->tp_event);
8061 if (prog->aux->max_ctx_offset > off) {
8066 event->tp_event->prog = prog;
8071 static void perf_event_free_bpf_prog(struct perf_event *event)
8073 struct bpf_prog *prog;
8075 perf_event_free_bpf_handler(event);
8077 if (!event->tp_event)
8080 prog = event->tp_event->prog;
8082 event->tp_event->prog = NULL;
8089 static inline void perf_tp_register(void)
8093 static void perf_event_free_filter(struct perf_event *event)
8097 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8102 static void perf_event_free_bpf_prog(struct perf_event *event)
8105 #endif /* CONFIG_EVENT_TRACING */
8107 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8108 void perf_bp_event(struct perf_event *bp, void *data)
8110 struct perf_sample_data sample;
8111 struct pt_regs *regs = data;
8113 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8115 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8116 perf_swevent_event(bp, 1, &sample, regs);
8121 * Allocate a new address filter
8123 static struct perf_addr_filter *
8124 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8126 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8127 struct perf_addr_filter *filter;
8129 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8133 INIT_LIST_HEAD(&filter->entry);
8134 list_add_tail(&filter->entry, filters);
8139 static void free_filters_list(struct list_head *filters)
8141 struct perf_addr_filter *filter, *iter;
8143 list_for_each_entry_safe(filter, iter, filters, entry) {
8145 iput(filter->inode);
8146 list_del(&filter->entry);
8152 * Free existing address filters and optionally install new ones
8154 static void perf_addr_filters_splice(struct perf_event *event,
8155 struct list_head *head)
8157 unsigned long flags;
8160 if (!has_addr_filter(event))
8163 /* don't bother with children, they don't have their own filters */
8167 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8169 list_splice_init(&event->addr_filters.list, &list);
8171 list_splice(head, &event->addr_filters.list);
8173 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8175 free_filters_list(&list);
8179 * Scan through mm's vmas and see if one of them matches the
8180 * @filter; if so, adjust filter's address range.
8181 * Called with mm::mmap_sem down for reading.
8183 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8184 struct mm_struct *mm)
8186 struct vm_area_struct *vma;
8188 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8189 struct file *file = vma->vm_file;
8190 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8191 unsigned long vma_size = vma->vm_end - vma->vm_start;
8196 if (!perf_addr_filter_match(filter, file, off, vma_size))
8199 return vma->vm_start;
8206 * Update event's address range filters based on the
8207 * task's existing mappings, if any.
8209 static void perf_event_addr_filters_apply(struct perf_event *event)
8211 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8212 struct task_struct *task = READ_ONCE(event->ctx->task);
8213 struct perf_addr_filter *filter;
8214 struct mm_struct *mm = NULL;
8215 unsigned int count = 0;
8216 unsigned long flags;
8219 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8220 * will stop on the parent's child_mutex that our caller is also holding
8222 if (task == TASK_TOMBSTONE)
8225 if (!ifh->nr_file_filters)
8228 mm = get_task_mm(event->ctx->task);
8232 down_read(&mm->mmap_sem);
8234 raw_spin_lock_irqsave(&ifh->lock, flags);
8235 list_for_each_entry(filter, &ifh->list, entry) {
8236 event->addr_filters_offs[count] = 0;
8239 * Adjust base offset if the filter is associated to a binary
8240 * that needs to be mapped:
8243 event->addr_filters_offs[count] =
8244 perf_addr_filter_apply(filter, mm);
8249 event->addr_filters_gen++;
8250 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8252 up_read(&mm->mmap_sem);
8257 perf_event_stop(event, 1);
8261 * Address range filtering: limiting the data to certain
8262 * instruction address ranges. Filters are ioctl()ed to us from
8263 * userspace as ascii strings.
8265 * Filter string format:
8268 * where ACTION is one of the
8269 * * "filter": limit the trace to this region
8270 * * "start": start tracing from this address
8271 * * "stop": stop tracing at this address/region;
8273 * * for kernel addresses: <start address>[/<size>]
8274 * * for object files: <start address>[/<size>]@</path/to/object/file>
8276 * if <size> is not specified, the range is treated as a single address.
8290 IF_STATE_ACTION = 0,
8295 static const match_table_t if_tokens = {
8296 { IF_ACT_FILTER, "filter" },
8297 { IF_ACT_START, "start" },
8298 { IF_ACT_STOP, "stop" },
8299 { IF_SRC_FILE, "%u/%u@%s" },
8300 { IF_SRC_KERNEL, "%u/%u" },
8301 { IF_SRC_FILEADDR, "%u@%s" },
8302 { IF_SRC_KERNELADDR, "%u" },
8303 { IF_ACT_NONE, NULL },
8307 * Address filter string parser
8310 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8311 struct list_head *filters)
8313 struct perf_addr_filter *filter = NULL;
8314 char *start, *orig, *filename = NULL;
8316 substring_t args[MAX_OPT_ARGS];
8317 int state = IF_STATE_ACTION, token;
8318 unsigned int kernel = 0;
8321 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8325 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8331 /* filter definition begins */
8332 if (state == IF_STATE_ACTION) {
8333 filter = perf_addr_filter_new(event, filters);
8338 token = match_token(start, if_tokens, args);
8345 if (state != IF_STATE_ACTION)
8348 state = IF_STATE_SOURCE;
8351 case IF_SRC_KERNELADDR:
8355 case IF_SRC_FILEADDR:
8357 if (state != IF_STATE_SOURCE)
8360 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8364 ret = kstrtoul(args[0].from, 0, &filter->offset);
8368 if (filter->range) {
8370 ret = kstrtoul(args[1].from, 0, &filter->size);
8375 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8376 int fpos = filter->range ? 2 : 1;
8378 filename = match_strdup(&args[fpos]);
8385 state = IF_STATE_END;
8393 * Filter definition is fully parsed, validate and install it.
8394 * Make sure that it doesn't contradict itself or the event's
8397 if (state == IF_STATE_END) {
8399 if (kernel && event->attr.exclude_kernel)
8407 * For now, we only support file-based filters
8408 * in per-task events; doing so for CPU-wide
8409 * events requires additional context switching
8410 * trickery, since same object code will be
8411 * mapped at different virtual addresses in
8412 * different processes.
8415 if (!event->ctx->task)
8416 goto fail_free_name;
8418 /* look up the path and grab its inode */
8419 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8421 goto fail_free_name;
8423 filter->inode = igrab(d_inode(path.dentry));
8429 if (!filter->inode ||
8430 !S_ISREG(filter->inode->i_mode))
8431 /* free_filters_list() will iput() */
8434 event->addr_filters.nr_file_filters++;
8437 /* ready to consume more filters */
8438 state = IF_STATE_ACTION;
8443 if (state != IF_STATE_ACTION)
8453 free_filters_list(filters);
8460 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8466 * Since this is called in perf_ioctl() path, we're already holding
8469 lockdep_assert_held(&event->ctx->mutex);
8471 if (WARN_ON_ONCE(event->parent))
8474 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8476 goto fail_clear_files;
8478 ret = event->pmu->addr_filters_validate(&filters);
8480 goto fail_free_filters;
8482 /* remove existing filters, if any */
8483 perf_addr_filters_splice(event, &filters);
8485 /* install new filters */
8486 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8491 free_filters_list(&filters);
8494 event->addr_filters.nr_file_filters = 0;
8499 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8504 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8505 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8506 !has_addr_filter(event))
8509 filter_str = strndup_user(arg, PAGE_SIZE);
8510 if (IS_ERR(filter_str))
8511 return PTR_ERR(filter_str);
8513 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8514 event->attr.type == PERF_TYPE_TRACEPOINT)
8515 ret = ftrace_profile_set_filter(event, event->attr.config,
8517 else if (has_addr_filter(event))
8518 ret = perf_event_set_addr_filter(event, filter_str);
8525 * hrtimer based swevent callback
8528 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8530 enum hrtimer_restart ret = HRTIMER_RESTART;
8531 struct perf_sample_data data;
8532 struct pt_regs *regs;
8533 struct perf_event *event;
8536 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8538 if (event->state != PERF_EVENT_STATE_ACTIVE)
8539 return HRTIMER_NORESTART;
8541 event->pmu->read(event);
8543 perf_sample_data_init(&data, 0, event->hw.last_period);
8544 regs = get_irq_regs();
8546 if (regs && !perf_exclude_event(event, regs)) {
8547 if (!(event->attr.exclude_idle && is_idle_task(current)))
8548 if (__perf_event_overflow(event, 1, &data, regs))
8549 ret = HRTIMER_NORESTART;
8552 period = max_t(u64, 10000, event->hw.sample_period);
8553 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8558 static void perf_swevent_start_hrtimer(struct perf_event *event)
8560 struct hw_perf_event *hwc = &event->hw;
8563 if (!is_sampling_event(event))
8566 period = local64_read(&hwc->period_left);
8571 local64_set(&hwc->period_left, 0);
8573 period = max_t(u64, 10000, hwc->sample_period);
8575 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8576 HRTIMER_MODE_REL_PINNED);
8579 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8581 struct hw_perf_event *hwc = &event->hw;
8583 if (is_sampling_event(event)) {
8584 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8585 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8587 hrtimer_cancel(&hwc->hrtimer);
8591 static void perf_swevent_init_hrtimer(struct perf_event *event)
8593 struct hw_perf_event *hwc = &event->hw;
8595 if (!is_sampling_event(event))
8598 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8599 hwc->hrtimer.function = perf_swevent_hrtimer;
8602 * Since hrtimers have a fixed rate, we can do a static freq->period
8603 * mapping and avoid the whole period adjust feedback stuff.
8605 if (event->attr.freq) {
8606 long freq = event->attr.sample_freq;
8608 event->attr.sample_period = NSEC_PER_SEC / freq;
8609 hwc->sample_period = event->attr.sample_period;
8610 local64_set(&hwc->period_left, hwc->sample_period);
8611 hwc->last_period = hwc->sample_period;
8612 event->attr.freq = 0;
8617 * Software event: cpu wall time clock
8620 static void cpu_clock_event_update(struct perf_event *event)
8625 now = local_clock();
8626 prev = local64_xchg(&event->hw.prev_count, now);
8627 local64_add(now - prev, &event->count);
8630 static void cpu_clock_event_start(struct perf_event *event, int flags)
8632 local64_set(&event->hw.prev_count, local_clock());
8633 perf_swevent_start_hrtimer(event);
8636 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8638 perf_swevent_cancel_hrtimer(event);
8639 cpu_clock_event_update(event);
8642 static int cpu_clock_event_add(struct perf_event *event, int flags)
8644 if (flags & PERF_EF_START)
8645 cpu_clock_event_start(event, flags);
8646 perf_event_update_userpage(event);
8651 static void cpu_clock_event_del(struct perf_event *event, int flags)
8653 cpu_clock_event_stop(event, flags);
8656 static void cpu_clock_event_read(struct perf_event *event)
8658 cpu_clock_event_update(event);
8661 static int cpu_clock_event_init(struct perf_event *event)
8663 if (event->attr.type != PERF_TYPE_SOFTWARE)
8666 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8670 * no branch sampling for software events
8672 if (has_branch_stack(event))
8675 perf_swevent_init_hrtimer(event);
8680 static struct pmu perf_cpu_clock = {
8681 .task_ctx_nr = perf_sw_context,
8683 .capabilities = PERF_PMU_CAP_NO_NMI,
8685 .event_init = cpu_clock_event_init,
8686 .add = cpu_clock_event_add,
8687 .del = cpu_clock_event_del,
8688 .start = cpu_clock_event_start,
8689 .stop = cpu_clock_event_stop,
8690 .read = cpu_clock_event_read,
8694 * Software event: task time clock
8697 static void task_clock_event_update(struct perf_event *event, u64 now)
8702 prev = local64_xchg(&event->hw.prev_count, now);
8704 local64_add(delta, &event->count);
8707 static void task_clock_event_start(struct perf_event *event, int flags)
8709 local64_set(&event->hw.prev_count, event->ctx->time);
8710 perf_swevent_start_hrtimer(event);
8713 static void task_clock_event_stop(struct perf_event *event, int flags)
8715 perf_swevent_cancel_hrtimer(event);
8716 task_clock_event_update(event, event->ctx->time);
8719 static int task_clock_event_add(struct perf_event *event, int flags)
8721 if (flags & PERF_EF_START)
8722 task_clock_event_start(event, flags);
8723 perf_event_update_userpage(event);
8728 static void task_clock_event_del(struct perf_event *event, int flags)
8730 task_clock_event_stop(event, PERF_EF_UPDATE);
8733 static void task_clock_event_read(struct perf_event *event)
8735 u64 now = perf_clock();
8736 u64 delta = now - event->ctx->timestamp;
8737 u64 time = event->ctx->time + delta;
8739 task_clock_event_update(event, time);
8742 static int task_clock_event_init(struct perf_event *event)
8744 if (event->attr.type != PERF_TYPE_SOFTWARE)
8747 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8751 * no branch sampling for software events
8753 if (has_branch_stack(event))
8756 perf_swevent_init_hrtimer(event);
8761 static struct pmu perf_task_clock = {
8762 .task_ctx_nr = perf_sw_context,
8764 .capabilities = PERF_PMU_CAP_NO_NMI,
8766 .event_init = task_clock_event_init,
8767 .add = task_clock_event_add,
8768 .del = task_clock_event_del,
8769 .start = task_clock_event_start,
8770 .stop = task_clock_event_stop,
8771 .read = task_clock_event_read,
8774 static void perf_pmu_nop_void(struct pmu *pmu)
8778 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8782 static int perf_pmu_nop_int(struct pmu *pmu)
8787 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8789 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8791 __this_cpu_write(nop_txn_flags, flags);
8793 if (flags & ~PERF_PMU_TXN_ADD)
8796 perf_pmu_disable(pmu);
8799 static int perf_pmu_commit_txn(struct pmu *pmu)
8801 unsigned int flags = __this_cpu_read(nop_txn_flags);
8803 __this_cpu_write(nop_txn_flags, 0);
8805 if (flags & ~PERF_PMU_TXN_ADD)
8808 perf_pmu_enable(pmu);
8812 static void perf_pmu_cancel_txn(struct pmu *pmu)
8814 unsigned int flags = __this_cpu_read(nop_txn_flags);
8816 __this_cpu_write(nop_txn_flags, 0);
8818 if (flags & ~PERF_PMU_TXN_ADD)
8821 perf_pmu_enable(pmu);
8824 static int perf_event_idx_default(struct perf_event *event)
8830 * Ensures all contexts with the same task_ctx_nr have the same
8831 * pmu_cpu_context too.
8833 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8840 list_for_each_entry(pmu, &pmus, entry) {
8841 if (pmu->task_ctx_nr == ctxn)
8842 return pmu->pmu_cpu_context;
8848 static void free_pmu_context(struct pmu *pmu)
8850 mutex_lock(&pmus_lock);
8851 free_percpu(pmu->pmu_cpu_context);
8852 mutex_unlock(&pmus_lock);
8856 * Let userspace know that this PMU supports address range filtering:
8858 static ssize_t nr_addr_filters_show(struct device *dev,
8859 struct device_attribute *attr,
8862 struct pmu *pmu = dev_get_drvdata(dev);
8864 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8866 DEVICE_ATTR_RO(nr_addr_filters);
8868 static struct idr pmu_idr;
8871 type_show(struct device *dev, struct device_attribute *attr, char *page)
8873 struct pmu *pmu = dev_get_drvdata(dev);
8875 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8877 static DEVICE_ATTR_RO(type);
8880 perf_event_mux_interval_ms_show(struct device *dev,
8881 struct device_attribute *attr,
8884 struct pmu *pmu = dev_get_drvdata(dev);
8886 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8889 static DEFINE_MUTEX(mux_interval_mutex);
8892 perf_event_mux_interval_ms_store(struct device *dev,
8893 struct device_attribute *attr,
8894 const char *buf, size_t count)
8896 struct pmu *pmu = dev_get_drvdata(dev);
8897 int timer, cpu, ret;
8899 ret = kstrtoint(buf, 0, &timer);
8906 /* same value, noting to do */
8907 if (timer == pmu->hrtimer_interval_ms)
8910 mutex_lock(&mux_interval_mutex);
8911 pmu->hrtimer_interval_ms = timer;
8913 /* update all cpuctx for this PMU */
8915 for_each_online_cpu(cpu) {
8916 struct perf_cpu_context *cpuctx;
8917 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8918 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8920 cpu_function_call(cpu,
8921 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8924 mutex_unlock(&mux_interval_mutex);
8928 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8930 static struct attribute *pmu_dev_attrs[] = {
8931 &dev_attr_type.attr,
8932 &dev_attr_perf_event_mux_interval_ms.attr,
8935 ATTRIBUTE_GROUPS(pmu_dev);
8937 static int pmu_bus_running;
8938 static struct bus_type pmu_bus = {
8939 .name = "event_source",
8940 .dev_groups = pmu_dev_groups,
8943 static void pmu_dev_release(struct device *dev)
8948 static int pmu_dev_alloc(struct pmu *pmu)
8952 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8956 pmu->dev->groups = pmu->attr_groups;
8957 device_initialize(pmu->dev);
8958 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8962 dev_set_drvdata(pmu->dev, pmu);
8963 pmu->dev->bus = &pmu_bus;
8964 pmu->dev->release = pmu_dev_release;
8965 ret = device_add(pmu->dev);
8969 /* For PMUs with address filters, throw in an extra attribute: */
8970 if (pmu->nr_addr_filters)
8971 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8980 device_del(pmu->dev);
8983 put_device(pmu->dev);
8987 static struct lock_class_key cpuctx_mutex;
8988 static struct lock_class_key cpuctx_lock;
8990 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
8994 mutex_lock(&pmus_lock);
8996 pmu->pmu_disable_count = alloc_percpu(int);
8997 if (!pmu->pmu_disable_count)
9006 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9014 if (pmu_bus_running) {
9015 ret = pmu_dev_alloc(pmu);
9021 if (pmu->task_ctx_nr == perf_hw_context) {
9022 static int hw_context_taken = 0;
9025 * Other than systems with heterogeneous CPUs, it never makes
9026 * sense for two PMUs to share perf_hw_context. PMUs which are
9027 * uncore must use perf_invalid_context.
9029 if (WARN_ON_ONCE(hw_context_taken &&
9030 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9031 pmu->task_ctx_nr = perf_invalid_context;
9033 hw_context_taken = 1;
9036 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9037 if (pmu->pmu_cpu_context)
9038 goto got_cpu_context;
9041 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9042 if (!pmu->pmu_cpu_context)
9045 for_each_possible_cpu(cpu) {
9046 struct perf_cpu_context *cpuctx;
9048 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9049 __perf_event_init_context(&cpuctx->ctx);
9050 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9051 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9052 cpuctx->ctx.pmu = pmu;
9053 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9055 __perf_mux_hrtimer_init(cpuctx, cpu);
9059 if (!pmu->start_txn) {
9060 if (pmu->pmu_enable) {
9062 * If we have pmu_enable/pmu_disable calls, install
9063 * transaction stubs that use that to try and batch
9064 * hardware accesses.
9066 pmu->start_txn = perf_pmu_start_txn;
9067 pmu->commit_txn = perf_pmu_commit_txn;
9068 pmu->cancel_txn = perf_pmu_cancel_txn;
9070 pmu->start_txn = perf_pmu_nop_txn;
9071 pmu->commit_txn = perf_pmu_nop_int;
9072 pmu->cancel_txn = perf_pmu_nop_void;
9076 if (!pmu->pmu_enable) {
9077 pmu->pmu_enable = perf_pmu_nop_void;
9078 pmu->pmu_disable = perf_pmu_nop_void;
9081 if (!pmu->event_idx)
9082 pmu->event_idx = perf_event_idx_default;
9084 list_add_rcu(&pmu->entry, &pmus);
9085 atomic_set(&pmu->exclusive_cnt, 0);
9088 mutex_unlock(&pmus_lock);
9093 device_del(pmu->dev);
9094 put_device(pmu->dev);
9097 if (pmu->type >= PERF_TYPE_MAX)
9098 idr_remove(&pmu_idr, pmu->type);
9101 free_percpu(pmu->pmu_disable_count);
9104 EXPORT_SYMBOL_GPL(perf_pmu_register);
9106 void perf_pmu_unregister(struct pmu *pmu)
9110 mutex_lock(&pmus_lock);
9111 remove_device = pmu_bus_running;
9112 list_del_rcu(&pmu->entry);
9113 mutex_unlock(&pmus_lock);
9116 * We dereference the pmu list under both SRCU and regular RCU, so
9117 * synchronize against both of those.
9119 synchronize_srcu(&pmus_srcu);
9122 free_percpu(pmu->pmu_disable_count);
9123 if (pmu->type >= PERF_TYPE_MAX)
9124 idr_remove(&pmu_idr, pmu->type);
9125 if (remove_device) {
9126 if (pmu->nr_addr_filters)
9127 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9128 device_del(pmu->dev);
9129 put_device(pmu->dev);
9131 free_pmu_context(pmu);
9133 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9135 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9137 struct perf_event_context *ctx = NULL;
9140 if (!try_module_get(pmu->module))
9143 if (event->group_leader != event) {
9145 * This ctx->mutex can nest when we're called through
9146 * inheritance. See the perf_event_ctx_lock_nested() comment.
9148 ctx = perf_event_ctx_lock_nested(event->group_leader,
9149 SINGLE_DEPTH_NESTING);
9154 ret = pmu->event_init(event);
9157 perf_event_ctx_unlock(event->group_leader, ctx);
9160 module_put(pmu->module);
9165 static struct pmu *perf_init_event(struct perf_event *event)
9171 idx = srcu_read_lock(&pmus_srcu);
9173 /* Try parent's PMU first: */
9174 if (event->parent && event->parent->pmu) {
9175 pmu = event->parent->pmu;
9176 ret = perf_try_init_event(pmu, event);
9182 pmu = idr_find(&pmu_idr, event->attr.type);
9185 ret = perf_try_init_event(pmu, event);
9191 list_for_each_entry_rcu(pmu, &pmus, entry) {
9192 ret = perf_try_init_event(pmu, event);
9196 if (ret != -ENOENT) {
9201 pmu = ERR_PTR(-ENOENT);
9203 srcu_read_unlock(&pmus_srcu, idx);
9208 static void attach_sb_event(struct perf_event *event)
9210 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9212 raw_spin_lock(&pel->lock);
9213 list_add_rcu(&event->sb_list, &pel->list);
9214 raw_spin_unlock(&pel->lock);
9218 * We keep a list of all !task (and therefore per-cpu) events
9219 * that need to receive side-band records.
9221 * This avoids having to scan all the various PMU per-cpu contexts
9224 static void account_pmu_sb_event(struct perf_event *event)
9226 if (is_sb_event(event))
9227 attach_sb_event(event);
9230 static void account_event_cpu(struct perf_event *event, int cpu)
9235 if (is_cgroup_event(event))
9236 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9239 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9240 static void account_freq_event_nohz(void)
9242 #ifdef CONFIG_NO_HZ_FULL
9243 /* Lock so we don't race with concurrent unaccount */
9244 spin_lock(&nr_freq_lock);
9245 if (atomic_inc_return(&nr_freq_events) == 1)
9246 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9247 spin_unlock(&nr_freq_lock);
9251 static void account_freq_event(void)
9253 if (tick_nohz_full_enabled())
9254 account_freq_event_nohz();
9256 atomic_inc(&nr_freq_events);
9260 static void account_event(struct perf_event *event)
9267 if (event->attach_state & PERF_ATTACH_TASK)
9269 if (event->attr.mmap || event->attr.mmap_data)
9270 atomic_inc(&nr_mmap_events);
9271 if (event->attr.comm)
9272 atomic_inc(&nr_comm_events);
9273 if (event->attr.namespaces)
9274 atomic_inc(&nr_namespaces_events);
9275 if (event->attr.task)
9276 atomic_inc(&nr_task_events);
9277 if (event->attr.freq)
9278 account_freq_event();
9279 if (event->attr.context_switch) {
9280 atomic_inc(&nr_switch_events);
9283 if (has_branch_stack(event))
9285 if (is_cgroup_event(event))
9289 if (atomic_inc_not_zero(&perf_sched_count))
9292 mutex_lock(&perf_sched_mutex);
9293 if (!atomic_read(&perf_sched_count)) {
9294 static_branch_enable(&perf_sched_events);
9296 * Guarantee that all CPUs observe they key change and
9297 * call the perf scheduling hooks before proceeding to
9298 * install events that need them.
9300 synchronize_sched();
9303 * Now that we have waited for the sync_sched(), allow further
9304 * increments to by-pass the mutex.
9306 atomic_inc(&perf_sched_count);
9307 mutex_unlock(&perf_sched_mutex);
9311 account_event_cpu(event, event->cpu);
9313 account_pmu_sb_event(event);
9317 * Allocate and initialize a event structure
9319 static struct perf_event *
9320 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9321 struct task_struct *task,
9322 struct perf_event *group_leader,
9323 struct perf_event *parent_event,
9324 perf_overflow_handler_t overflow_handler,
9325 void *context, int cgroup_fd)
9328 struct perf_event *event;
9329 struct hw_perf_event *hwc;
9332 if ((unsigned)cpu >= nr_cpu_ids) {
9333 if (!task || cpu != -1)
9334 return ERR_PTR(-EINVAL);
9337 event = kzalloc(sizeof(*event), GFP_KERNEL);
9339 return ERR_PTR(-ENOMEM);
9342 * Single events are their own group leaders, with an
9343 * empty sibling list:
9346 group_leader = event;
9348 mutex_init(&event->child_mutex);
9349 INIT_LIST_HEAD(&event->child_list);
9351 INIT_LIST_HEAD(&event->group_entry);
9352 INIT_LIST_HEAD(&event->event_entry);
9353 INIT_LIST_HEAD(&event->sibling_list);
9354 INIT_LIST_HEAD(&event->rb_entry);
9355 INIT_LIST_HEAD(&event->active_entry);
9356 INIT_LIST_HEAD(&event->addr_filters.list);
9357 INIT_HLIST_NODE(&event->hlist_entry);
9360 init_waitqueue_head(&event->waitq);
9361 init_irq_work(&event->pending, perf_pending_event);
9363 mutex_init(&event->mmap_mutex);
9364 raw_spin_lock_init(&event->addr_filters.lock);
9366 atomic_long_set(&event->refcount, 1);
9368 event->attr = *attr;
9369 event->group_leader = group_leader;
9373 event->parent = parent_event;
9375 event->ns = get_pid_ns(task_active_pid_ns(current));
9376 event->id = atomic64_inc_return(&perf_event_id);
9378 event->state = PERF_EVENT_STATE_INACTIVE;
9381 event->attach_state = PERF_ATTACH_TASK;
9383 * XXX pmu::event_init needs to know what task to account to
9384 * and we cannot use the ctx information because we need the
9385 * pmu before we get a ctx.
9387 event->hw.target = task;
9390 event->clock = &local_clock;
9392 event->clock = parent_event->clock;
9394 if (!overflow_handler && parent_event) {
9395 overflow_handler = parent_event->overflow_handler;
9396 context = parent_event->overflow_handler_context;
9397 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9398 if (overflow_handler == bpf_overflow_handler) {
9399 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9402 err = PTR_ERR(prog);
9406 event->orig_overflow_handler =
9407 parent_event->orig_overflow_handler;
9412 if (overflow_handler) {
9413 event->overflow_handler = overflow_handler;
9414 event->overflow_handler_context = context;
9415 } else if (is_write_backward(event)){
9416 event->overflow_handler = perf_event_output_backward;
9417 event->overflow_handler_context = NULL;
9419 event->overflow_handler = perf_event_output_forward;
9420 event->overflow_handler_context = NULL;
9423 perf_event__state_init(event);
9428 hwc->sample_period = attr->sample_period;
9429 if (attr->freq && attr->sample_freq)
9430 hwc->sample_period = 1;
9431 hwc->last_period = hwc->sample_period;
9433 local64_set(&hwc->period_left, hwc->sample_period);
9436 * We currently do not support PERF_SAMPLE_READ on inherited events.
9437 * See perf_output_read().
9439 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9442 if (!has_branch_stack(event))
9443 event->attr.branch_sample_type = 0;
9445 if (cgroup_fd != -1) {
9446 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9451 pmu = perf_init_event(event);
9457 err = exclusive_event_init(event);
9461 if (has_addr_filter(event)) {
9462 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9463 sizeof(unsigned long),
9465 if (!event->addr_filters_offs) {
9470 /* force hw sync on the address filters */
9471 event->addr_filters_gen = 1;
9474 if (!event->parent) {
9475 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9476 err = get_callchain_buffers(attr->sample_max_stack);
9478 goto err_addr_filters;
9482 /* symmetric to unaccount_event() in _free_event() */
9483 account_event(event);
9488 kfree(event->addr_filters_offs);
9491 exclusive_event_destroy(event);
9495 event->destroy(event);
9496 module_put(pmu->module);
9498 if (is_cgroup_event(event))
9499 perf_detach_cgroup(event);
9501 put_pid_ns(event->ns);
9504 return ERR_PTR(err);
9507 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9508 struct perf_event_attr *attr)
9513 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9517 * zero the full structure, so that a short copy will be nice.
9519 memset(attr, 0, sizeof(*attr));
9521 ret = get_user(size, &uattr->size);
9525 if (size > PAGE_SIZE) /* silly large */
9528 if (!size) /* abi compat */
9529 size = PERF_ATTR_SIZE_VER0;
9531 if (size < PERF_ATTR_SIZE_VER0)
9535 * If we're handed a bigger struct than we know of,
9536 * ensure all the unknown bits are 0 - i.e. new
9537 * user-space does not rely on any kernel feature
9538 * extensions we dont know about yet.
9540 if (size > sizeof(*attr)) {
9541 unsigned char __user *addr;
9542 unsigned char __user *end;
9545 addr = (void __user *)uattr + sizeof(*attr);
9546 end = (void __user *)uattr + size;
9548 for (; addr < end; addr++) {
9549 ret = get_user(val, addr);
9555 size = sizeof(*attr);
9558 ret = copy_from_user(attr, uattr, size);
9562 if (attr->__reserved_1)
9565 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9568 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9571 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9572 u64 mask = attr->branch_sample_type;
9574 /* only using defined bits */
9575 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9578 /* at least one branch bit must be set */
9579 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9582 /* propagate priv level, when not set for branch */
9583 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9585 /* exclude_kernel checked on syscall entry */
9586 if (!attr->exclude_kernel)
9587 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9589 if (!attr->exclude_user)
9590 mask |= PERF_SAMPLE_BRANCH_USER;
9592 if (!attr->exclude_hv)
9593 mask |= PERF_SAMPLE_BRANCH_HV;
9595 * adjust user setting (for HW filter setup)
9597 attr->branch_sample_type = mask;
9599 /* privileged levels capture (kernel, hv): check permissions */
9600 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9601 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9605 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9606 ret = perf_reg_validate(attr->sample_regs_user);
9611 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9612 if (!arch_perf_have_user_stack_dump())
9616 * We have __u32 type for the size, but so far
9617 * we can only use __u16 as maximum due to the
9618 * __u16 sample size limit.
9620 if (attr->sample_stack_user >= USHRT_MAX)
9622 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9626 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9627 ret = perf_reg_validate(attr->sample_regs_intr);
9632 put_user(sizeof(*attr), &uattr->size);
9638 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9640 struct ring_buffer *rb = NULL;
9646 /* don't allow circular references */
9647 if (event == output_event)
9651 * Don't allow cross-cpu buffers
9653 if (output_event->cpu != event->cpu)
9657 * If its not a per-cpu rb, it must be the same task.
9659 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9663 * Mixing clocks in the same buffer is trouble you don't need.
9665 if (output_event->clock != event->clock)
9669 * Either writing ring buffer from beginning or from end.
9670 * Mixing is not allowed.
9672 if (is_write_backward(output_event) != is_write_backward(event))
9676 * If both events generate aux data, they must be on the same PMU
9678 if (has_aux(event) && has_aux(output_event) &&
9679 event->pmu != output_event->pmu)
9683 mutex_lock(&event->mmap_mutex);
9684 /* Can't redirect output if we've got an active mmap() */
9685 if (atomic_read(&event->mmap_count))
9689 /* get the rb we want to redirect to */
9690 rb = ring_buffer_get(output_event);
9695 ring_buffer_attach(event, rb);
9699 mutex_unlock(&event->mmap_mutex);
9705 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9711 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9714 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9716 bool nmi_safe = false;
9719 case CLOCK_MONOTONIC:
9720 event->clock = &ktime_get_mono_fast_ns;
9724 case CLOCK_MONOTONIC_RAW:
9725 event->clock = &ktime_get_raw_fast_ns;
9729 case CLOCK_REALTIME:
9730 event->clock = &ktime_get_real_ns;
9733 case CLOCK_BOOTTIME:
9734 event->clock = &ktime_get_boot_ns;
9738 event->clock = &ktime_get_tai_ns;
9745 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9752 * Variation on perf_event_ctx_lock_nested(), except we take two context
9755 static struct perf_event_context *
9756 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9757 struct perf_event_context *ctx)
9759 struct perf_event_context *gctx;
9763 gctx = READ_ONCE(group_leader->ctx);
9764 if (!atomic_inc_not_zero(&gctx->refcount)) {
9770 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9772 if (group_leader->ctx != gctx) {
9773 mutex_unlock(&ctx->mutex);
9774 mutex_unlock(&gctx->mutex);
9783 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9785 * @attr_uptr: event_id type attributes for monitoring/sampling
9788 * @group_fd: group leader event fd
9790 SYSCALL_DEFINE5(perf_event_open,
9791 struct perf_event_attr __user *, attr_uptr,
9792 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9794 struct perf_event *group_leader = NULL, *output_event = NULL;
9795 struct perf_event *event, *sibling;
9796 struct perf_event_attr attr;
9797 struct perf_event_context *ctx, *uninitialized_var(gctx);
9798 struct file *event_file = NULL;
9799 struct fd group = {NULL, 0};
9800 struct task_struct *task = NULL;
9805 int f_flags = O_RDWR;
9808 /* for future expandability... */
9809 if (flags & ~PERF_FLAG_ALL)
9812 err = perf_copy_attr(attr_uptr, &attr);
9816 if (!attr.exclude_kernel) {
9817 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9821 if (attr.namespaces) {
9822 if (!capable(CAP_SYS_ADMIN))
9827 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9830 if (attr.sample_period & (1ULL << 63))
9834 if (!attr.sample_max_stack)
9835 attr.sample_max_stack = sysctl_perf_event_max_stack;
9838 * In cgroup mode, the pid argument is used to pass the fd
9839 * opened to the cgroup directory in cgroupfs. The cpu argument
9840 * designates the cpu on which to monitor threads from that
9843 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9846 if (flags & PERF_FLAG_FD_CLOEXEC)
9847 f_flags |= O_CLOEXEC;
9849 event_fd = get_unused_fd_flags(f_flags);
9853 if (group_fd != -1) {
9854 err = perf_fget_light(group_fd, &group);
9857 group_leader = group.file->private_data;
9858 if (flags & PERF_FLAG_FD_OUTPUT)
9859 output_event = group_leader;
9860 if (flags & PERF_FLAG_FD_NO_GROUP)
9861 group_leader = NULL;
9864 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9865 task = find_lively_task_by_vpid(pid);
9867 err = PTR_ERR(task);
9872 if (task && group_leader &&
9873 group_leader->attr.inherit != attr.inherit) {
9879 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9884 * Reuse ptrace permission checks for now.
9886 * We must hold cred_guard_mutex across this and any potential
9887 * perf_install_in_context() call for this new event to
9888 * serialize against exec() altering our credentials (and the
9889 * perf_event_exit_task() that could imply).
9892 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9896 if (flags & PERF_FLAG_PID_CGROUP)
9899 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9900 NULL, NULL, cgroup_fd);
9901 if (IS_ERR(event)) {
9902 err = PTR_ERR(event);
9906 if (is_sampling_event(event)) {
9907 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9914 * Special case software events and allow them to be part of
9915 * any hardware group.
9919 if (attr.use_clockid) {
9920 err = perf_event_set_clock(event, attr.clockid);
9925 if (pmu->task_ctx_nr == perf_sw_context)
9926 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9929 (is_software_event(event) != is_software_event(group_leader))) {
9930 if (is_software_event(event)) {
9932 * If event and group_leader are not both a software
9933 * event, and event is, then group leader is not.
9935 * Allow the addition of software events to !software
9936 * groups, this is safe because software events never
9939 pmu = group_leader->pmu;
9940 } else if (is_software_event(group_leader) &&
9941 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9943 * In case the group is a pure software group, and we
9944 * try to add a hardware event, move the whole group to
9945 * the hardware context.
9952 * Get the target context (task or percpu):
9954 ctx = find_get_context(pmu, task, event);
9960 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9966 * Look up the group leader (we will attach this event to it):
9972 * Do not allow a recursive hierarchy (this new sibling
9973 * becoming part of another group-sibling):
9975 if (group_leader->group_leader != group_leader)
9978 /* All events in a group should have the same clock */
9979 if (group_leader->clock != event->clock)
9983 * Do not allow to attach to a group in a different
9984 * task or CPU context:
9988 * Make sure we're both on the same task, or both
9991 if (group_leader->ctx->task != ctx->task)
9995 * Make sure we're both events for the same CPU;
9996 * grouping events for different CPUs is broken; since
9997 * you can never concurrently schedule them anyhow.
9999 if (group_leader->cpu != event->cpu)
10002 if (group_leader->ctx != ctx)
10007 * Only a group leader can be exclusive or pinned
10009 if (attr.exclusive || attr.pinned)
10013 if (output_event) {
10014 err = perf_event_set_output(event, output_event);
10019 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10021 if (IS_ERR(event_file)) {
10022 err = PTR_ERR(event_file);
10028 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10030 if (gctx->task == TASK_TOMBSTONE) {
10036 * Check if we raced against another sys_perf_event_open() call
10037 * moving the software group underneath us.
10039 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10041 * If someone moved the group out from under us, check
10042 * if this new event wound up on the same ctx, if so
10043 * its the regular !move_group case, otherwise fail.
10049 perf_event_ctx_unlock(group_leader, gctx);
10054 mutex_lock(&ctx->mutex);
10057 if (ctx->task == TASK_TOMBSTONE) {
10062 if (!perf_event_validate_size(event)) {
10069 * Check if the @cpu we're creating an event for is online.
10071 * We use the perf_cpu_context::ctx::mutex to serialize against
10072 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10074 struct perf_cpu_context *cpuctx =
10075 container_of(ctx, struct perf_cpu_context, ctx);
10077 if (!cpuctx->online) {
10085 * Must be under the same ctx::mutex as perf_install_in_context(),
10086 * because we need to serialize with concurrent event creation.
10088 if (!exclusive_event_installable(event, ctx)) {
10089 /* exclusive and group stuff are assumed mutually exclusive */
10090 WARN_ON_ONCE(move_group);
10096 WARN_ON_ONCE(ctx->parent_ctx);
10099 * This is the point on no return; we cannot fail hereafter. This is
10100 * where we start modifying current state.
10105 * See perf_event_ctx_lock() for comments on the details
10106 * of swizzling perf_event::ctx.
10108 perf_remove_from_context(group_leader, 0);
10111 list_for_each_entry(sibling, &group_leader->sibling_list,
10113 perf_remove_from_context(sibling, 0);
10118 * Wait for everybody to stop referencing the events through
10119 * the old lists, before installing it on new lists.
10124 * Install the group siblings before the group leader.
10126 * Because a group leader will try and install the entire group
10127 * (through the sibling list, which is still in-tact), we can
10128 * end up with siblings installed in the wrong context.
10130 * By installing siblings first we NO-OP because they're not
10131 * reachable through the group lists.
10133 list_for_each_entry(sibling, &group_leader->sibling_list,
10135 perf_event__state_init(sibling);
10136 perf_install_in_context(ctx, sibling, sibling->cpu);
10141 * Removing from the context ends up with disabled
10142 * event. What we want here is event in the initial
10143 * startup state, ready to be add into new context.
10145 perf_event__state_init(group_leader);
10146 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10151 * Precalculate sample_data sizes; do while holding ctx::mutex such
10152 * that we're serialized against further additions and before
10153 * perf_install_in_context() which is the point the event is active and
10154 * can use these values.
10156 perf_event__header_size(event);
10157 perf_event__id_header_size(event);
10159 event->owner = current;
10161 perf_install_in_context(ctx, event, event->cpu);
10162 perf_unpin_context(ctx);
10165 perf_event_ctx_unlock(group_leader, gctx);
10166 mutex_unlock(&ctx->mutex);
10169 mutex_unlock(&task->signal->cred_guard_mutex);
10170 put_task_struct(task);
10173 mutex_lock(¤t->perf_event_mutex);
10174 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10175 mutex_unlock(¤t->perf_event_mutex);
10178 * Drop the reference on the group_event after placing the
10179 * new event on the sibling_list. This ensures destruction
10180 * of the group leader will find the pointer to itself in
10181 * perf_group_detach().
10184 fd_install(event_fd, event_file);
10189 perf_event_ctx_unlock(group_leader, gctx);
10190 mutex_unlock(&ctx->mutex);
10194 perf_unpin_context(ctx);
10198 * If event_file is set, the fput() above will have called ->release()
10199 * and that will take care of freeing the event.
10205 mutex_unlock(&task->signal->cred_guard_mutex);
10208 put_task_struct(task);
10212 put_unused_fd(event_fd);
10217 * perf_event_create_kernel_counter
10219 * @attr: attributes of the counter to create
10220 * @cpu: cpu in which the counter is bound
10221 * @task: task to profile (NULL for percpu)
10223 struct perf_event *
10224 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10225 struct task_struct *task,
10226 perf_overflow_handler_t overflow_handler,
10229 struct perf_event_context *ctx;
10230 struct perf_event *event;
10234 * Get the target context (task or percpu):
10237 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10238 overflow_handler, context, -1);
10239 if (IS_ERR(event)) {
10240 err = PTR_ERR(event);
10244 /* Mark owner so we could distinguish it from user events. */
10245 event->owner = TASK_TOMBSTONE;
10247 ctx = find_get_context(event->pmu, task, event);
10249 err = PTR_ERR(ctx);
10253 WARN_ON_ONCE(ctx->parent_ctx);
10254 mutex_lock(&ctx->mutex);
10255 if (ctx->task == TASK_TOMBSTONE) {
10262 * Check if the @cpu we're creating an event for is online.
10264 * We use the perf_cpu_context::ctx::mutex to serialize against
10265 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10267 struct perf_cpu_context *cpuctx =
10268 container_of(ctx, struct perf_cpu_context, ctx);
10269 if (!cpuctx->online) {
10275 if (!exclusive_event_installable(event, ctx)) {
10280 perf_install_in_context(ctx, event, cpu);
10281 perf_unpin_context(ctx);
10282 mutex_unlock(&ctx->mutex);
10287 mutex_unlock(&ctx->mutex);
10288 perf_unpin_context(ctx);
10293 return ERR_PTR(err);
10295 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10297 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10299 struct perf_event_context *src_ctx;
10300 struct perf_event_context *dst_ctx;
10301 struct perf_event *event, *tmp;
10304 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10305 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10308 * See perf_event_ctx_lock() for comments on the details
10309 * of swizzling perf_event::ctx.
10311 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10312 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10314 perf_remove_from_context(event, 0);
10315 unaccount_event_cpu(event, src_cpu);
10317 list_add(&event->migrate_entry, &events);
10321 * Wait for the events to quiesce before re-instating them.
10326 * Re-instate events in 2 passes.
10328 * Skip over group leaders and only install siblings on this first
10329 * pass, siblings will not get enabled without a leader, however a
10330 * leader will enable its siblings, even if those are still on the old
10333 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10334 if (event->group_leader == event)
10337 list_del(&event->migrate_entry);
10338 if (event->state >= PERF_EVENT_STATE_OFF)
10339 event->state = PERF_EVENT_STATE_INACTIVE;
10340 account_event_cpu(event, dst_cpu);
10341 perf_install_in_context(dst_ctx, event, dst_cpu);
10346 * Once all the siblings are setup properly, install the group leaders
10349 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10350 list_del(&event->migrate_entry);
10351 if (event->state >= PERF_EVENT_STATE_OFF)
10352 event->state = PERF_EVENT_STATE_INACTIVE;
10353 account_event_cpu(event, dst_cpu);
10354 perf_install_in_context(dst_ctx, event, dst_cpu);
10357 mutex_unlock(&dst_ctx->mutex);
10358 mutex_unlock(&src_ctx->mutex);
10360 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10362 static void sync_child_event(struct perf_event *child_event,
10363 struct task_struct *child)
10365 struct perf_event *parent_event = child_event->parent;
10368 if (child_event->attr.inherit_stat)
10369 perf_event_read_event(child_event, child);
10371 child_val = perf_event_count(child_event);
10374 * Add back the child's count to the parent's count:
10376 atomic64_add(child_val, &parent_event->child_count);
10377 atomic64_add(child_event->total_time_enabled,
10378 &parent_event->child_total_time_enabled);
10379 atomic64_add(child_event->total_time_running,
10380 &parent_event->child_total_time_running);
10384 perf_event_exit_event(struct perf_event *child_event,
10385 struct perf_event_context *child_ctx,
10386 struct task_struct *child)
10388 struct perf_event *parent_event = child_event->parent;
10391 * Do not destroy the 'original' grouping; because of the context
10392 * switch optimization the original events could've ended up in a
10393 * random child task.
10395 * If we were to destroy the original group, all group related
10396 * operations would cease to function properly after this random
10399 * Do destroy all inherited groups, we don't care about those
10400 * and being thorough is better.
10402 raw_spin_lock_irq(&child_ctx->lock);
10403 WARN_ON_ONCE(child_ctx->is_active);
10406 perf_group_detach(child_event);
10407 list_del_event(child_event, child_ctx);
10408 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10409 raw_spin_unlock_irq(&child_ctx->lock);
10412 * Parent events are governed by their filedesc, retain them.
10414 if (!parent_event) {
10415 perf_event_wakeup(child_event);
10419 * Child events can be cleaned up.
10422 sync_child_event(child_event, child);
10425 * Remove this event from the parent's list
10427 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10428 mutex_lock(&parent_event->child_mutex);
10429 list_del_init(&child_event->child_list);
10430 mutex_unlock(&parent_event->child_mutex);
10433 * Kick perf_poll() for is_event_hup().
10435 perf_event_wakeup(parent_event);
10436 free_event(child_event);
10437 put_event(parent_event);
10440 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10442 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10443 struct perf_event *child_event, *next;
10445 WARN_ON_ONCE(child != current);
10447 child_ctx = perf_pin_task_context(child, ctxn);
10452 * In order to reduce the amount of tricky in ctx tear-down, we hold
10453 * ctx::mutex over the entire thing. This serializes against almost
10454 * everything that wants to access the ctx.
10456 * The exception is sys_perf_event_open() /
10457 * perf_event_create_kernel_count() which does find_get_context()
10458 * without ctx::mutex (it cannot because of the move_group double mutex
10459 * lock thing). See the comments in perf_install_in_context().
10461 mutex_lock(&child_ctx->mutex);
10464 * In a single ctx::lock section, de-schedule the events and detach the
10465 * context from the task such that we cannot ever get it scheduled back
10468 raw_spin_lock_irq(&child_ctx->lock);
10469 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10472 * Now that the context is inactive, destroy the task <-> ctx relation
10473 * and mark the context dead.
10475 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10476 put_ctx(child_ctx); /* cannot be last */
10477 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10478 put_task_struct(current); /* cannot be last */
10480 clone_ctx = unclone_ctx(child_ctx);
10481 raw_spin_unlock_irq(&child_ctx->lock);
10484 put_ctx(clone_ctx);
10487 * Report the task dead after unscheduling the events so that we
10488 * won't get any samples after PERF_RECORD_EXIT. We can however still
10489 * get a few PERF_RECORD_READ events.
10491 perf_event_task(child, child_ctx, 0);
10493 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10494 perf_event_exit_event(child_event, child_ctx, child);
10496 mutex_unlock(&child_ctx->mutex);
10498 put_ctx(child_ctx);
10502 * When a child task exits, feed back event values to parent events.
10504 * Can be called with cred_guard_mutex held when called from
10505 * install_exec_creds().
10507 void perf_event_exit_task(struct task_struct *child)
10509 struct perf_event *event, *tmp;
10512 mutex_lock(&child->perf_event_mutex);
10513 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10515 list_del_init(&event->owner_entry);
10518 * Ensure the list deletion is visible before we clear
10519 * the owner, closes a race against perf_release() where
10520 * we need to serialize on the owner->perf_event_mutex.
10522 smp_store_release(&event->owner, NULL);
10524 mutex_unlock(&child->perf_event_mutex);
10526 for_each_task_context_nr(ctxn)
10527 perf_event_exit_task_context(child, ctxn);
10530 * The perf_event_exit_task_context calls perf_event_task
10531 * with child's task_ctx, which generates EXIT events for
10532 * child contexts and sets child->perf_event_ctxp[] to NULL.
10533 * At this point we need to send EXIT events to cpu contexts.
10535 perf_event_task(child, NULL, 0);
10538 static void perf_free_event(struct perf_event *event,
10539 struct perf_event_context *ctx)
10541 struct perf_event *parent = event->parent;
10543 if (WARN_ON_ONCE(!parent))
10546 mutex_lock(&parent->child_mutex);
10547 list_del_init(&event->child_list);
10548 mutex_unlock(&parent->child_mutex);
10552 raw_spin_lock_irq(&ctx->lock);
10553 perf_group_detach(event);
10554 list_del_event(event, ctx);
10555 raw_spin_unlock_irq(&ctx->lock);
10560 * Free an unexposed, unused context as created by inheritance by
10561 * perf_event_init_task below, used by fork() in case of fail.
10563 * Not all locks are strictly required, but take them anyway to be nice and
10564 * help out with the lockdep assertions.
10566 void perf_event_free_task(struct task_struct *task)
10568 struct perf_event_context *ctx;
10569 struct perf_event *event, *tmp;
10572 for_each_task_context_nr(ctxn) {
10573 ctx = task->perf_event_ctxp[ctxn];
10577 mutex_lock(&ctx->mutex);
10578 raw_spin_lock_irq(&ctx->lock);
10580 * Destroy the task <-> ctx relation and mark the context dead.
10582 * This is important because even though the task hasn't been
10583 * exposed yet the context has been (through child_list).
10585 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10586 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10587 put_task_struct(task); /* cannot be last */
10588 raw_spin_unlock_irq(&ctx->lock);
10590 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10591 perf_free_event(event, ctx);
10593 mutex_unlock(&ctx->mutex);
10598 void perf_event_delayed_put(struct task_struct *task)
10602 for_each_task_context_nr(ctxn)
10603 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10606 struct file *perf_event_get(unsigned int fd)
10610 file = fget_raw(fd);
10612 return ERR_PTR(-EBADF);
10614 if (file->f_op != &perf_fops) {
10616 return ERR_PTR(-EBADF);
10622 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10625 return ERR_PTR(-EINVAL);
10627 return &event->attr;
10631 * Inherit a event from parent task to child task.
10634 * - valid pointer on success
10635 * - NULL for orphaned events
10636 * - IS_ERR() on error
10638 static struct perf_event *
10639 inherit_event(struct perf_event *parent_event,
10640 struct task_struct *parent,
10641 struct perf_event_context *parent_ctx,
10642 struct task_struct *child,
10643 struct perf_event *group_leader,
10644 struct perf_event_context *child_ctx)
10646 enum perf_event_active_state parent_state = parent_event->state;
10647 struct perf_event *child_event;
10648 unsigned long flags;
10651 * Instead of creating recursive hierarchies of events,
10652 * we link inherited events back to the original parent,
10653 * which has a filp for sure, which we use as the reference
10656 if (parent_event->parent)
10657 parent_event = parent_event->parent;
10659 child_event = perf_event_alloc(&parent_event->attr,
10662 group_leader, parent_event,
10664 if (IS_ERR(child_event))
10665 return child_event;
10668 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10669 * must be under the same lock in order to serialize against
10670 * perf_event_release_kernel(), such that either we must observe
10671 * is_orphaned_event() or they will observe us on the child_list.
10673 mutex_lock(&parent_event->child_mutex);
10674 if (is_orphaned_event(parent_event) ||
10675 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10676 mutex_unlock(&parent_event->child_mutex);
10677 free_event(child_event);
10681 get_ctx(child_ctx);
10684 * Make the child state follow the state of the parent event,
10685 * not its attr.disabled bit. We hold the parent's mutex,
10686 * so we won't race with perf_event_{en, dis}able_family.
10688 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10689 child_event->state = PERF_EVENT_STATE_INACTIVE;
10691 child_event->state = PERF_EVENT_STATE_OFF;
10693 if (parent_event->attr.freq) {
10694 u64 sample_period = parent_event->hw.sample_period;
10695 struct hw_perf_event *hwc = &child_event->hw;
10697 hwc->sample_period = sample_period;
10698 hwc->last_period = sample_period;
10700 local64_set(&hwc->period_left, sample_period);
10703 child_event->ctx = child_ctx;
10704 child_event->overflow_handler = parent_event->overflow_handler;
10705 child_event->overflow_handler_context
10706 = parent_event->overflow_handler_context;
10709 * Precalculate sample_data sizes
10711 perf_event__header_size(child_event);
10712 perf_event__id_header_size(child_event);
10715 * Link it up in the child's context:
10717 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10718 add_event_to_ctx(child_event, child_ctx);
10719 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10722 * Link this into the parent event's child list
10724 list_add_tail(&child_event->child_list, &parent_event->child_list);
10725 mutex_unlock(&parent_event->child_mutex);
10727 return child_event;
10731 * Inherits an event group.
10733 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10734 * This matches with perf_event_release_kernel() removing all child events.
10740 static int inherit_group(struct perf_event *parent_event,
10741 struct task_struct *parent,
10742 struct perf_event_context *parent_ctx,
10743 struct task_struct *child,
10744 struct perf_event_context *child_ctx)
10746 struct perf_event *leader;
10747 struct perf_event *sub;
10748 struct perf_event *child_ctr;
10750 leader = inherit_event(parent_event, parent, parent_ctx,
10751 child, NULL, child_ctx);
10752 if (IS_ERR(leader))
10753 return PTR_ERR(leader);
10755 * @leader can be NULL here because of is_orphaned_event(). In this
10756 * case inherit_event() will create individual events, similar to what
10757 * perf_group_detach() would do anyway.
10759 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10760 child_ctr = inherit_event(sub, parent, parent_ctx,
10761 child, leader, child_ctx);
10762 if (IS_ERR(child_ctr))
10763 return PTR_ERR(child_ctr);
10769 * Creates the child task context and tries to inherit the event-group.
10771 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10772 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10773 * consistent with perf_event_release_kernel() removing all child events.
10780 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10781 struct perf_event_context *parent_ctx,
10782 struct task_struct *child, int ctxn,
10783 int *inherited_all)
10786 struct perf_event_context *child_ctx;
10788 if (!event->attr.inherit) {
10789 *inherited_all = 0;
10793 child_ctx = child->perf_event_ctxp[ctxn];
10796 * This is executed from the parent task context, so
10797 * inherit events that have been marked for cloning.
10798 * First allocate and initialize a context for the
10801 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10805 child->perf_event_ctxp[ctxn] = child_ctx;
10808 ret = inherit_group(event, parent, parent_ctx,
10812 *inherited_all = 0;
10818 * Initialize the perf_event context in task_struct
10820 static int perf_event_init_context(struct task_struct *child, int ctxn)
10822 struct perf_event_context *child_ctx, *parent_ctx;
10823 struct perf_event_context *cloned_ctx;
10824 struct perf_event *event;
10825 struct task_struct *parent = current;
10826 int inherited_all = 1;
10827 unsigned long flags;
10830 if (likely(!parent->perf_event_ctxp[ctxn]))
10834 * If the parent's context is a clone, pin it so it won't get
10835 * swapped under us.
10837 parent_ctx = perf_pin_task_context(parent, ctxn);
10842 * No need to check if parent_ctx != NULL here; since we saw
10843 * it non-NULL earlier, the only reason for it to become NULL
10844 * is if we exit, and since we're currently in the middle of
10845 * a fork we can't be exiting at the same time.
10849 * Lock the parent list. No need to lock the child - not PID
10850 * hashed yet and not running, so nobody can access it.
10852 mutex_lock(&parent_ctx->mutex);
10855 * We dont have to disable NMIs - we are only looking at
10856 * the list, not manipulating it:
10858 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10859 ret = inherit_task_group(event, parent, parent_ctx,
10860 child, ctxn, &inherited_all);
10866 * We can't hold ctx->lock when iterating the ->flexible_group list due
10867 * to allocations, but we need to prevent rotation because
10868 * rotate_ctx() will change the list from interrupt context.
10870 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10871 parent_ctx->rotate_disable = 1;
10872 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10874 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10875 ret = inherit_task_group(event, parent, parent_ctx,
10876 child, ctxn, &inherited_all);
10881 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10882 parent_ctx->rotate_disable = 0;
10884 child_ctx = child->perf_event_ctxp[ctxn];
10886 if (child_ctx && inherited_all) {
10888 * Mark the child context as a clone of the parent
10889 * context, or of whatever the parent is a clone of.
10891 * Note that if the parent is a clone, the holding of
10892 * parent_ctx->lock avoids it from being uncloned.
10894 cloned_ctx = parent_ctx->parent_ctx;
10896 child_ctx->parent_ctx = cloned_ctx;
10897 child_ctx->parent_gen = parent_ctx->parent_gen;
10899 child_ctx->parent_ctx = parent_ctx;
10900 child_ctx->parent_gen = parent_ctx->generation;
10902 get_ctx(child_ctx->parent_ctx);
10905 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10907 mutex_unlock(&parent_ctx->mutex);
10909 perf_unpin_context(parent_ctx);
10910 put_ctx(parent_ctx);
10916 * Initialize the perf_event context in task_struct
10918 int perf_event_init_task(struct task_struct *child)
10922 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10923 mutex_init(&child->perf_event_mutex);
10924 INIT_LIST_HEAD(&child->perf_event_list);
10926 for_each_task_context_nr(ctxn) {
10927 ret = perf_event_init_context(child, ctxn);
10929 perf_event_free_task(child);
10937 static void __init perf_event_init_all_cpus(void)
10939 struct swevent_htable *swhash;
10942 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
10944 for_each_possible_cpu(cpu) {
10945 swhash = &per_cpu(swevent_htable, cpu);
10946 mutex_init(&swhash->hlist_mutex);
10947 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10949 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10950 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10952 #ifdef CONFIG_CGROUP_PERF
10953 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10955 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10959 void perf_swevent_init_cpu(unsigned int cpu)
10961 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10963 mutex_lock(&swhash->hlist_mutex);
10964 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10965 struct swevent_hlist *hlist;
10967 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10969 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10971 mutex_unlock(&swhash->hlist_mutex);
10974 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10975 static void __perf_event_exit_context(void *__info)
10977 struct perf_event_context *ctx = __info;
10978 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10979 struct perf_event *event;
10981 raw_spin_lock(&ctx->lock);
10982 list_for_each_entry(event, &ctx->event_list, event_entry)
10983 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10984 raw_spin_unlock(&ctx->lock);
10987 static void perf_event_exit_cpu_context(int cpu)
10989 struct perf_cpu_context *cpuctx;
10990 struct perf_event_context *ctx;
10993 mutex_lock(&pmus_lock);
10994 list_for_each_entry(pmu, &pmus, entry) {
10995 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10996 ctx = &cpuctx->ctx;
10998 mutex_lock(&ctx->mutex);
10999 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11000 cpuctx->online = 0;
11001 mutex_unlock(&ctx->mutex);
11003 cpumask_clear_cpu(cpu, perf_online_mask);
11004 mutex_unlock(&pmus_lock);
11008 static void perf_event_exit_cpu_context(int cpu) { }
11012 int perf_event_init_cpu(unsigned int cpu)
11014 struct perf_cpu_context *cpuctx;
11015 struct perf_event_context *ctx;
11018 perf_swevent_init_cpu(cpu);
11020 mutex_lock(&pmus_lock);
11021 cpumask_set_cpu(cpu, perf_online_mask);
11022 list_for_each_entry(pmu, &pmus, entry) {
11023 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11024 ctx = &cpuctx->ctx;
11026 mutex_lock(&ctx->mutex);
11027 cpuctx->online = 1;
11028 mutex_unlock(&ctx->mutex);
11030 mutex_unlock(&pmus_lock);
11035 int perf_event_exit_cpu(unsigned int cpu)
11037 perf_event_exit_cpu_context(cpu);
11042 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11046 for_each_online_cpu(cpu)
11047 perf_event_exit_cpu(cpu);
11053 * Run the perf reboot notifier at the very last possible moment so that
11054 * the generic watchdog code runs as long as possible.
11056 static struct notifier_block perf_reboot_notifier = {
11057 .notifier_call = perf_reboot,
11058 .priority = INT_MIN,
11061 void __init perf_event_init(void)
11065 idr_init(&pmu_idr);
11067 perf_event_init_all_cpus();
11068 init_srcu_struct(&pmus_srcu);
11069 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11070 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11071 perf_pmu_register(&perf_task_clock, NULL, -1);
11072 perf_tp_register();
11073 perf_event_init_cpu(smp_processor_id());
11074 register_reboot_notifier(&perf_reboot_notifier);
11076 ret = init_hw_breakpoint();
11077 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11080 * Build time assertion that we keep the data_head at the intended
11081 * location. IOW, validation we got the __reserved[] size right.
11083 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11087 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11090 struct perf_pmu_events_attr *pmu_attr =
11091 container_of(attr, struct perf_pmu_events_attr, attr);
11093 if (pmu_attr->event_str)
11094 return sprintf(page, "%s\n", pmu_attr->event_str);
11098 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11100 static int __init perf_event_sysfs_init(void)
11105 mutex_lock(&pmus_lock);
11107 ret = bus_register(&pmu_bus);
11111 list_for_each_entry(pmu, &pmus, entry) {
11112 if (!pmu->name || pmu->type < 0)
11115 ret = pmu_dev_alloc(pmu);
11116 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11118 pmu_bus_running = 1;
11122 mutex_unlock(&pmus_lock);
11126 device_initcall(perf_event_sysfs_init);
11128 #ifdef CONFIG_CGROUP_PERF
11129 static struct cgroup_subsys_state *
11130 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11132 struct perf_cgroup *jc;
11134 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11136 return ERR_PTR(-ENOMEM);
11138 jc->info = alloc_percpu(struct perf_cgroup_info);
11141 return ERR_PTR(-ENOMEM);
11147 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11149 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11151 free_percpu(jc->info);
11155 static int __perf_cgroup_move(void *info)
11157 struct task_struct *task = info;
11159 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11164 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11166 struct task_struct *task;
11167 struct cgroup_subsys_state *css;
11169 cgroup_taskset_for_each(task, css, tset)
11170 task_function_call(task, __perf_cgroup_move, task);
11173 struct cgroup_subsys perf_event_cgrp_subsys = {
11174 .css_alloc = perf_cgroup_css_alloc,
11175 .css_free = perf_cgroup_css_free,
11176 .attach = perf_cgroup_attach,
11178 * Implicitly enable on dfl hierarchy so that perf events can
11179 * always be filtered by cgroup2 path as long as perf_event
11180 * controller is not mounted on a legacy hierarchy.
11182 .implicit_on_dfl = true,
11184 #endif /* CONFIG_CGROUP_PERF */