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);
1456 * It's 'group type', really, because if our group leader is
1457 * pinned, so are we.
1459 if (event->group_leader != event)
1460 event = event->group_leader;
1462 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1464 event_type |= EVENT_CPU;
1469 static struct list_head *
1470 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1472 if (event->attr.pinned)
1473 return &ctx->pinned_groups;
1475 return &ctx->flexible_groups;
1479 * Add a event from the lists for its context.
1480 * Must be called with ctx->mutex and ctx->lock held.
1483 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1485 lockdep_assert_held(&ctx->lock);
1487 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1488 event->attach_state |= PERF_ATTACH_CONTEXT;
1491 * If we're a stand alone event or group leader, we go to the context
1492 * list, group events are kept attached to the group so that
1493 * perf_group_detach can, at all times, locate all siblings.
1495 if (event->group_leader == event) {
1496 struct list_head *list;
1498 event->group_caps = event->event_caps;
1500 list = ctx_group_list(event, ctx);
1501 list_add_tail(&event->group_entry, list);
1504 list_update_cgroup_event(event, ctx, true);
1506 list_add_rcu(&event->event_entry, &ctx->event_list);
1508 if (event->attr.inherit_stat)
1515 * Initialize event state based on the perf_event_attr::disabled.
1517 static inline void perf_event__state_init(struct perf_event *event)
1519 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1520 PERF_EVENT_STATE_INACTIVE;
1523 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1525 int entry = sizeof(u64); /* value */
1529 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1530 size += sizeof(u64);
1532 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1533 size += sizeof(u64);
1535 if (event->attr.read_format & PERF_FORMAT_ID)
1536 entry += sizeof(u64);
1538 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1540 size += sizeof(u64);
1544 event->read_size = size;
1547 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1549 struct perf_sample_data *data;
1552 if (sample_type & PERF_SAMPLE_IP)
1553 size += sizeof(data->ip);
1555 if (sample_type & PERF_SAMPLE_ADDR)
1556 size += sizeof(data->addr);
1558 if (sample_type & PERF_SAMPLE_PERIOD)
1559 size += sizeof(data->period);
1561 if (sample_type & PERF_SAMPLE_WEIGHT)
1562 size += sizeof(data->weight);
1564 if (sample_type & PERF_SAMPLE_READ)
1565 size += event->read_size;
1567 if (sample_type & PERF_SAMPLE_DATA_SRC)
1568 size += sizeof(data->data_src.val);
1570 if (sample_type & PERF_SAMPLE_TRANSACTION)
1571 size += sizeof(data->txn);
1573 event->header_size = size;
1577 * Called at perf_event creation and when events are attached/detached from a
1580 static void perf_event__header_size(struct perf_event *event)
1582 __perf_event_read_size(event,
1583 event->group_leader->nr_siblings);
1584 __perf_event_header_size(event, event->attr.sample_type);
1587 static void perf_event__id_header_size(struct perf_event *event)
1589 struct perf_sample_data *data;
1590 u64 sample_type = event->attr.sample_type;
1593 if (sample_type & PERF_SAMPLE_TID)
1594 size += sizeof(data->tid_entry);
1596 if (sample_type & PERF_SAMPLE_TIME)
1597 size += sizeof(data->time);
1599 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1600 size += sizeof(data->id);
1602 if (sample_type & PERF_SAMPLE_ID)
1603 size += sizeof(data->id);
1605 if (sample_type & PERF_SAMPLE_STREAM_ID)
1606 size += sizeof(data->stream_id);
1608 if (sample_type & PERF_SAMPLE_CPU)
1609 size += sizeof(data->cpu_entry);
1611 event->id_header_size = size;
1614 static bool perf_event_validate_size(struct perf_event *event)
1617 * The values computed here will be over-written when we actually
1620 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1621 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1622 perf_event__id_header_size(event);
1625 * Sum the lot; should not exceed the 64k limit we have on records.
1626 * Conservative limit to allow for callchains and other variable fields.
1628 if (event->read_size + event->header_size +
1629 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1635 static void perf_group_attach(struct perf_event *event)
1637 struct perf_event *group_leader = event->group_leader, *pos;
1639 lockdep_assert_held(&event->ctx->lock);
1642 * We can have double attach due to group movement in perf_event_open.
1644 if (event->attach_state & PERF_ATTACH_GROUP)
1647 event->attach_state |= PERF_ATTACH_GROUP;
1649 if (group_leader == event)
1652 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1654 group_leader->group_caps &= event->event_caps;
1656 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1657 group_leader->nr_siblings++;
1659 perf_event__header_size(group_leader);
1661 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1662 perf_event__header_size(pos);
1666 * Remove a event from the lists for its context.
1667 * Must be called with ctx->mutex and ctx->lock held.
1670 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1672 WARN_ON_ONCE(event->ctx != ctx);
1673 lockdep_assert_held(&ctx->lock);
1676 * We can have double detach due to exit/hot-unplug + close.
1678 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1681 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1683 list_update_cgroup_event(event, ctx, false);
1686 if (event->attr.inherit_stat)
1689 list_del_rcu(&event->event_entry);
1691 if (event->group_leader == event)
1692 list_del_init(&event->group_entry);
1694 update_group_times(event);
1697 * If event was in error state, then keep it
1698 * that way, otherwise bogus counts will be
1699 * returned on read(). The only way to get out
1700 * of error state is by explicit re-enabling
1703 if (event->state > PERF_EVENT_STATE_OFF)
1704 event->state = PERF_EVENT_STATE_OFF;
1709 static void perf_group_detach(struct perf_event *event)
1711 struct perf_event *sibling, *tmp;
1712 struct list_head *list = NULL;
1714 lockdep_assert_held(&event->ctx->lock);
1717 * We can have double detach due to exit/hot-unplug + close.
1719 if (!(event->attach_state & PERF_ATTACH_GROUP))
1722 event->attach_state &= ~PERF_ATTACH_GROUP;
1725 * If this is a sibling, remove it from its group.
1727 if (event->group_leader != event) {
1728 list_del_init(&event->group_entry);
1729 event->group_leader->nr_siblings--;
1733 if (!list_empty(&event->group_entry))
1734 list = &event->group_entry;
1737 * If this was a group event with sibling events then
1738 * upgrade the siblings to singleton events by adding them
1739 * to whatever list we are on.
1741 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1743 list_move_tail(&sibling->group_entry, list);
1744 sibling->group_leader = sibling;
1746 /* Inherit group flags from the previous leader */
1747 sibling->group_caps = event->group_caps;
1749 WARN_ON_ONCE(sibling->ctx != event->ctx);
1753 perf_event__header_size(event->group_leader);
1755 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1756 perf_event__header_size(tmp);
1759 static bool is_orphaned_event(struct perf_event *event)
1761 return event->state == PERF_EVENT_STATE_DEAD;
1764 static inline int __pmu_filter_match(struct perf_event *event)
1766 struct pmu *pmu = event->pmu;
1767 return pmu->filter_match ? pmu->filter_match(event) : 1;
1771 * Check whether we should attempt to schedule an event group based on
1772 * PMU-specific filtering. An event group can consist of HW and SW events,
1773 * potentially with a SW leader, so we must check all the filters, to
1774 * determine whether a group is schedulable:
1776 static inline int pmu_filter_match(struct perf_event *event)
1778 struct perf_event *child;
1780 if (!__pmu_filter_match(event))
1783 list_for_each_entry(child, &event->sibling_list, group_entry) {
1784 if (!__pmu_filter_match(child))
1792 event_filter_match(struct perf_event *event)
1794 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1795 perf_cgroup_match(event) && pmu_filter_match(event);
1799 event_sched_out(struct perf_event *event,
1800 struct perf_cpu_context *cpuctx,
1801 struct perf_event_context *ctx)
1803 u64 tstamp = perf_event_time(event);
1806 WARN_ON_ONCE(event->ctx != ctx);
1807 lockdep_assert_held(&ctx->lock);
1810 * An event which could not be activated because of
1811 * filter mismatch still needs to have its timings
1812 * maintained, otherwise bogus information is return
1813 * via read() for time_enabled, time_running:
1815 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1816 !event_filter_match(event)) {
1817 delta = tstamp - event->tstamp_stopped;
1818 event->tstamp_running += delta;
1819 event->tstamp_stopped = tstamp;
1822 if (event->state != PERF_EVENT_STATE_ACTIVE)
1825 perf_pmu_disable(event->pmu);
1827 event->tstamp_stopped = tstamp;
1828 event->pmu->del(event, 0);
1830 event->state = PERF_EVENT_STATE_INACTIVE;
1831 if (event->pending_disable) {
1832 event->pending_disable = 0;
1833 event->state = PERF_EVENT_STATE_OFF;
1836 if (!is_software_event(event))
1837 cpuctx->active_oncpu--;
1838 if (!--ctx->nr_active)
1839 perf_event_ctx_deactivate(ctx);
1840 if (event->attr.freq && event->attr.sample_freq)
1842 if (event->attr.exclusive || !cpuctx->active_oncpu)
1843 cpuctx->exclusive = 0;
1845 perf_pmu_enable(event->pmu);
1849 group_sched_out(struct perf_event *group_event,
1850 struct perf_cpu_context *cpuctx,
1851 struct perf_event_context *ctx)
1853 struct perf_event *event;
1854 int state = group_event->state;
1856 perf_pmu_disable(ctx->pmu);
1858 event_sched_out(group_event, cpuctx, ctx);
1861 * Schedule out siblings (if any):
1863 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1864 event_sched_out(event, cpuctx, ctx);
1866 perf_pmu_enable(ctx->pmu);
1868 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1869 cpuctx->exclusive = 0;
1872 #define DETACH_GROUP 0x01UL
1875 * Cross CPU call to remove a performance event
1877 * We disable the event on the hardware level first. After that we
1878 * remove it from the context list.
1881 __perf_remove_from_context(struct perf_event *event,
1882 struct perf_cpu_context *cpuctx,
1883 struct perf_event_context *ctx,
1886 unsigned long flags = (unsigned long)info;
1888 event_sched_out(event, cpuctx, ctx);
1889 if (flags & DETACH_GROUP)
1890 perf_group_detach(event);
1891 list_del_event(event, ctx);
1893 if (!ctx->nr_events && ctx->is_active) {
1896 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1897 cpuctx->task_ctx = NULL;
1903 * Remove the event from a task's (or a CPU's) list of events.
1905 * If event->ctx is a cloned context, callers must make sure that
1906 * every task struct that event->ctx->task could possibly point to
1907 * remains valid. This is OK when called from perf_release since
1908 * that only calls us on the top-level context, which can't be a clone.
1909 * When called from perf_event_exit_task, it's OK because the
1910 * context has been detached from its task.
1912 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1914 struct perf_event_context *ctx = event->ctx;
1916 lockdep_assert_held(&ctx->mutex);
1918 event_function_call(event, __perf_remove_from_context, (void *)flags);
1921 * The above event_function_call() can NO-OP when it hits
1922 * TASK_TOMBSTONE. In that case we must already have been detached
1923 * from the context (by perf_event_exit_event()) but the grouping
1924 * might still be in-tact.
1926 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1927 if ((flags & DETACH_GROUP) &&
1928 (event->attach_state & PERF_ATTACH_GROUP)) {
1930 * Since in that case we cannot possibly be scheduled, simply
1933 raw_spin_lock_irq(&ctx->lock);
1934 perf_group_detach(event);
1935 raw_spin_unlock_irq(&ctx->lock);
1940 * Cross CPU call to disable a performance event
1942 static void __perf_event_disable(struct perf_event *event,
1943 struct perf_cpu_context *cpuctx,
1944 struct perf_event_context *ctx,
1947 if (event->state < PERF_EVENT_STATE_INACTIVE)
1950 update_context_time(ctx);
1951 update_cgrp_time_from_event(event);
1952 update_group_times(event);
1953 if (event == event->group_leader)
1954 group_sched_out(event, cpuctx, ctx);
1956 event_sched_out(event, cpuctx, ctx);
1957 event->state = PERF_EVENT_STATE_OFF;
1963 * If event->ctx is a cloned context, callers must make sure that
1964 * every task struct that event->ctx->task could possibly point to
1965 * remains valid. This condition is satisifed when called through
1966 * perf_event_for_each_child or perf_event_for_each because they
1967 * hold the top-level event's child_mutex, so any descendant that
1968 * goes to exit will block in perf_event_exit_event().
1970 * When called from perf_pending_event it's OK because event->ctx
1971 * is the current context on this CPU and preemption is disabled,
1972 * hence we can't get into perf_event_task_sched_out for this context.
1974 static void _perf_event_disable(struct perf_event *event)
1976 struct perf_event_context *ctx = event->ctx;
1978 raw_spin_lock_irq(&ctx->lock);
1979 if (event->state <= PERF_EVENT_STATE_OFF) {
1980 raw_spin_unlock_irq(&ctx->lock);
1983 raw_spin_unlock_irq(&ctx->lock);
1985 event_function_call(event, __perf_event_disable, NULL);
1988 void perf_event_disable_local(struct perf_event *event)
1990 event_function_local(event, __perf_event_disable, NULL);
1994 * Strictly speaking kernel users cannot create groups and therefore this
1995 * interface does not need the perf_event_ctx_lock() magic.
1997 void perf_event_disable(struct perf_event *event)
1999 struct perf_event_context *ctx;
2001 ctx = perf_event_ctx_lock(event);
2002 _perf_event_disable(event);
2003 perf_event_ctx_unlock(event, ctx);
2005 EXPORT_SYMBOL_GPL(perf_event_disable);
2007 void perf_event_disable_inatomic(struct perf_event *event)
2009 event->pending_disable = 1;
2010 irq_work_queue(&event->pending);
2013 static void perf_set_shadow_time(struct perf_event *event,
2014 struct perf_event_context *ctx,
2018 * use the correct time source for the time snapshot
2020 * We could get by without this by leveraging the
2021 * fact that to get to this function, the caller
2022 * has most likely already called update_context_time()
2023 * and update_cgrp_time_xx() and thus both timestamp
2024 * are identical (or very close). Given that tstamp is,
2025 * already adjusted for cgroup, we could say that:
2026 * tstamp - ctx->timestamp
2028 * tstamp - cgrp->timestamp.
2030 * Then, in perf_output_read(), the calculation would
2031 * work with no changes because:
2032 * - event is guaranteed scheduled in
2033 * - no scheduled out in between
2034 * - thus the timestamp would be the same
2036 * But this is a bit hairy.
2038 * So instead, we have an explicit cgroup call to remain
2039 * within the time time source all along. We believe it
2040 * is cleaner and simpler to understand.
2042 if (is_cgroup_event(event))
2043 perf_cgroup_set_shadow_time(event, tstamp);
2045 event->shadow_ctx_time = tstamp - ctx->timestamp;
2048 #define MAX_INTERRUPTS (~0ULL)
2050 static void perf_log_throttle(struct perf_event *event, int enable);
2051 static void perf_log_itrace_start(struct perf_event *event);
2054 event_sched_in(struct perf_event *event,
2055 struct perf_cpu_context *cpuctx,
2056 struct perf_event_context *ctx)
2058 u64 tstamp = perf_event_time(event);
2061 lockdep_assert_held(&ctx->lock);
2063 if (event->state <= PERF_EVENT_STATE_OFF)
2066 WRITE_ONCE(event->oncpu, smp_processor_id());
2068 * Order event::oncpu write to happen before the ACTIVE state
2072 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2075 * Unthrottle events, since we scheduled we might have missed several
2076 * ticks already, also for a heavily scheduling task there is little
2077 * guarantee it'll get a tick in a timely manner.
2079 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2080 perf_log_throttle(event, 1);
2081 event->hw.interrupts = 0;
2085 * The new state must be visible before we turn it on in the hardware:
2089 perf_pmu_disable(event->pmu);
2091 perf_set_shadow_time(event, ctx, tstamp);
2093 perf_log_itrace_start(event);
2095 if (event->pmu->add(event, PERF_EF_START)) {
2096 event->state = PERF_EVENT_STATE_INACTIVE;
2102 event->tstamp_running += tstamp - event->tstamp_stopped;
2104 if (!is_software_event(event))
2105 cpuctx->active_oncpu++;
2106 if (!ctx->nr_active++)
2107 perf_event_ctx_activate(ctx);
2108 if (event->attr.freq && event->attr.sample_freq)
2111 if (event->attr.exclusive)
2112 cpuctx->exclusive = 1;
2115 perf_pmu_enable(event->pmu);
2121 group_sched_in(struct perf_event *group_event,
2122 struct perf_cpu_context *cpuctx,
2123 struct perf_event_context *ctx)
2125 struct perf_event *event, *partial_group = NULL;
2126 struct pmu *pmu = ctx->pmu;
2127 u64 now = ctx->time;
2128 bool simulate = false;
2130 if (group_event->state == PERF_EVENT_STATE_OFF)
2133 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2135 if (event_sched_in(group_event, cpuctx, ctx)) {
2136 pmu->cancel_txn(pmu);
2137 perf_mux_hrtimer_restart(cpuctx);
2142 * Schedule in siblings as one group (if any):
2144 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2145 if (event_sched_in(event, cpuctx, ctx)) {
2146 partial_group = event;
2151 if (!pmu->commit_txn(pmu))
2156 * Groups can be scheduled in as one unit only, so undo any
2157 * partial group before returning:
2158 * The events up to the failed event are scheduled out normally,
2159 * tstamp_stopped will be updated.
2161 * The failed events and the remaining siblings need to have
2162 * their timings updated as if they had gone thru event_sched_in()
2163 * and event_sched_out(). This is required to get consistent timings
2164 * across the group. This also takes care of the case where the group
2165 * could never be scheduled by ensuring tstamp_stopped is set to mark
2166 * the time the event was actually stopped, such that time delta
2167 * calculation in update_event_times() is correct.
2169 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2170 if (event == partial_group)
2174 event->tstamp_running += now - event->tstamp_stopped;
2175 event->tstamp_stopped = now;
2177 event_sched_out(event, cpuctx, ctx);
2180 event_sched_out(group_event, cpuctx, ctx);
2182 pmu->cancel_txn(pmu);
2184 perf_mux_hrtimer_restart(cpuctx);
2190 * Work out whether we can put this event group on the CPU now.
2192 static int group_can_go_on(struct perf_event *event,
2193 struct perf_cpu_context *cpuctx,
2197 * Groups consisting entirely of software events can always go on.
2199 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2202 * If an exclusive group is already on, no other hardware
2205 if (cpuctx->exclusive)
2208 * If this group is exclusive and there are already
2209 * events on the CPU, it can't go on.
2211 if (event->attr.exclusive && cpuctx->active_oncpu)
2214 * Otherwise, try to add it if all previous groups were able
2220 static void add_event_to_ctx(struct perf_event *event,
2221 struct perf_event_context *ctx)
2223 u64 tstamp = perf_event_time(event);
2225 list_add_event(event, ctx);
2226 perf_group_attach(event);
2227 event->tstamp_enabled = tstamp;
2228 event->tstamp_running = tstamp;
2229 event->tstamp_stopped = tstamp;
2232 static void ctx_sched_out(struct perf_event_context *ctx,
2233 struct perf_cpu_context *cpuctx,
2234 enum event_type_t event_type);
2236 ctx_sched_in(struct perf_event_context *ctx,
2237 struct perf_cpu_context *cpuctx,
2238 enum event_type_t event_type,
2239 struct task_struct *task);
2241 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2242 struct perf_event_context *ctx,
2243 enum event_type_t event_type)
2245 if (!cpuctx->task_ctx)
2248 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2251 ctx_sched_out(ctx, cpuctx, event_type);
2254 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2255 struct perf_event_context *ctx,
2256 struct task_struct *task)
2258 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2260 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2261 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2263 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2267 * We want to maintain the following priority of scheduling:
2268 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2269 * - task pinned (EVENT_PINNED)
2270 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2271 * - task flexible (EVENT_FLEXIBLE).
2273 * In order to avoid unscheduling and scheduling back in everything every
2274 * time an event is added, only do it for the groups of equal priority and
2277 * This can be called after a batch operation on task events, in which case
2278 * event_type is a bit mask of the types of events involved. For CPU events,
2279 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2281 static void ctx_resched(struct perf_cpu_context *cpuctx,
2282 struct perf_event_context *task_ctx,
2283 enum event_type_t event_type)
2285 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2286 bool cpu_event = !!(event_type & EVENT_CPU);
2289 * If pinned groups are involved, flexible groups also need to be
2292 if (event_type & EVENT_PINNED)
2293 event_type |= EVENT_FLEXIBLE;
2295 perf_pmu_disable(cpuctx->ctx.pmu);
2297 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2300 * Decide which cpu ctx groups to schedule out based on the types
2301 * of events that caused rescheduling:
2302 * - EVENT_CPU: schedule out corresponding groups;
2303 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2304 * - otherwise, do nothing more.
2307 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2308 else if (ctx_event_type & EVENT_PINNED)
2309 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2311 perf_event_sched_in(cpuctx, task_ctx, current);
2312 perf_pmu_enable(cpuctx->ctx.pmu);
2316 * Cross CPU call to install and enable a performance event
2318 * Very similar to remote_function() + event_function() but cannot assume that
2319 * things like ctx->is_active and cpuctx->task_ctx are set.
2321 static int __perf_install_in_context(void *info)
2323 struct perf_event *event = info;
2324 struct perf_event_context *ctx = event->ctx;
2325 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2326 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2327 bool reprogram = true;
2330 raw_spin_lock(&cpuctx->ctx.lock);
2332 raw_spin_lock(&ctx->lock);
2335 reprogram = (ctx->task == current);
2338 * If the task is running, it must be running on this CPU,
2339 * otherwise we cannot reprogram things.
2341 * If its not running, we don't care, ctx->lock will
2342 * serialize against it becoming runnable.
2344 if (task_curr(ctx->task) && !reprogram) {
2349 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2350 } else if (task_ctx) {
2351 raw_spin_lock(&task_ctx->lock);
2355 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2356 add_event_to_ctx(event, ctx);
2357 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2359 add_event_to_ctx(event, ctx);
2363 perf_ctx_unlock(cpuctx, task_ctx);
2369 * Attach a performance event to a context.
2371 * Very similar to event_function_call, see comment there.
2374 perf_install_in_context(struct perf_event_context *ctx,
2375 struct perf_event *event,
2378 struct task_struct *task = READ_ONCE(ctx->task);
2380 lockdep_assert_held(&ctx->mutex);
2382 if (event->cpu != -1)
2386 * Ensures that if we can observe event->ctx, both the event and ctx
2387 * will be 'complete'. See perf_iterate_sb_cpu().
2389 smp_store_release(&event->ctx, ctx);
2392 cpu_function_call(cpu, __perf_install_in_context, event);
2397 * Should not happen, we validate the ctx is still alive before calling.
2399 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2403 * Installing events is tricky because we cannot rely on ctx->is_active
2404 * to be set in case this is the nr_events 0 -> 1 transition.
2406 * Instead we use task_curr(), which tells us if the task is running.
2407 * However, since we use task_curr() outside of rq::lock, we can race
2408 * against the actual state. This means the result can be wrong.
2410 * If we get a false positive, we retry, this is harmless.
2412 * If we get a false negative, things are complicated. If we are after
2413 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2414 * value must be correct. If we're before, it doesn't matter since
2415 * perf_event_context_sched_in() will program the counter.
2417 * However, this hinges on the remote context switch having observed
2418 * our task->perf_event_ctxp[] store, such that it will in fact take
2419 * ctx::lock in perf_event_context_sched_in().
2421 * We do this by task_function_call(), if the IPI fails to hit the task
2422 * we know any future context switch of task must see the
2423 * perf_event_ctpx[] store.
2427 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2428 * task_cpu() load, such that if the IPI then does not find the task
2429 * running, a future context switch of that task must observe the
2434 if (!task_function_call(task, __perf_install_in_context, event))
2437 raw_spin_lock_irq(&ctx->lock);
2439 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2441 * Cannot happen because we already checked above (which also
2442 * cannot happen), and we hold ctx->mutex, which serializes us
2443 * against perf_event_exit_task_context().
2445 raw_spin_unlock_irq(&ctx->lock);
2449 * If the task is not running, ctx->lock will avoid it becoming so,
2450 * thus we can safely install the event.
2452 if (task_curr(task)) {
2453 raw_spin_unlock_irq(&ctx->lock);
2456 add_event_to_ctx(event, ctx);
2457 raw_spin_unlock_irq(&ctx->lock);
2461 * Put a event into inactive state and update time fields.
2462 * Enabling the leader of a group effectively enables all
2463 * the group members that aren't explicitly disabled, so we
2464 * have to update their ->tstamp_enabled also.
2465 * Note: this works for group members as well as group leaders
2466 * since the non-leader members' sibling_lists will be empty.
2468 static void __perf_event_mark_enabled(struct perf_event *event)
2470 struct perf_event *sub;
2471 u64 tstamp = perf_event_time(event);
2473 event->state = PERF_EVENT_STATE_INACTIVE;
2474 event->tstamp_enabled = tstamp - event->total_time_enabled;
2475 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2476 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2477 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2482 * Cross CPU call to enable a performance event
2484 static void __perf_event_enable(struct perf_event *event,
2485 struct perf_cpu_context *cpuctx,
2486 struct perf_event_context *ctx,
2489 struct perf_event *leader = event->group_leader;
2490 struct perf_event_context *task_ctx;
2492 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2493 event->state <= PERF_EVENT_STATE_ERROR)
2497 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2499 __perf_event_mark_enabled(event);
2501 if (!ctx->is_active)
2504 if (!event_filter_match(event)) {
2505 if (is_cgroup_event(event))
2506 perf_cgroup_defer_enabled(event);
2507 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2512 * If the event is in a group and isn't the group leader,
2513 * then don't put it on unless the group is on.
2515 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2516 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2520 task_ctx = cpuctx->task_ctx;
2522 WARN_ON_ONCE(task_ctx != ctx);
2524 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2530 * If event->ctx is a cloned context, callers must make sure that
2531 * every task struct that event->ctx->task could possibly point to
2532 * remains valid. This condition is satisfied when called through
2533 * perf_event_for_each_child or perf_event_for_each as described
2534 * for perf_event_disable.
2536 static void _perf_event_enable(struct perf_event *event)
2538 struct perf_event_context *ctx = event->ctx;
2540 raw_spin_lock_irq(&ctx->lock);
2541 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2542 event->state < PERF_EVENT_STATE_ERROR) {
2543 raw_spin_unlock_irq(&ctx->lock);
2548 * If the event is in error state, clear that first.
2550 * That way, if we see the event in error state below, we know that it
2551 * has gone back into error state, as distinct from the task having
2552 * been scheduled away before the cross-call arrived.
2554 if (event->state == PERF_EVENT_STATE_ERROR)
2555 event->state = PERF_EVENT_STATE_OFF;
2556 raw_spin_unlock_irq(&ctx->lock);
2558 event_function_call(event, __perf_event_enable, NULL);
2562 * See perf_event_disable();
2564 void perf_event_enable(struct perf_event *event)
2566 struct perf_event_context *ctx;
2568 ctx = perf_event_ctx_lock(event);
2569 _perf_event_enable(event);
2570 perf_event_ctx_unlock(event, ctx);
2572 EXPORT_SYMBOL_GPL(perf_event_enable);
2574 struct stop_event_data {
2575 struct perf_event *event;
2576 unsigned int restart;
2579 static int __perf_event_stop(void *info)
2581 struct stop_event_data *sd = info;
2582 struct perf_event *event = sd->event;
2584 /* if it's already INACTIVE, do nothing */
2585 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2588 /* matches smp_wmb() in event_sched_in() */
2592 * There is a window with interrupts enabled before we get here,
2593 * so we need to check again lest we try to stop another CPU's event.
2595 if (READ_ONCE(event->oncpu) != smp_processor_id())
2598 event->pmu->stop(event, PERF_EF_UPDATE);
2601 * May race with the actual stop (through perf_pmu_output_stop()),
2602 * but it is only used for events with AUX ring buffer, and such
2603 * events will refuse to restart because of rb::aux_mmap_count==0,
2604 * see comments in perf_aux_output_begin().
2606 * Since this is happening on a event-local CPU, no trace is lost
2610 event->pmu->start(event, 0);
2615 static int perf_event_stop(struct perf_event *event, int restart)
2617 struct stop_event_data sd = {
2624 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2627 /* matches smp_wmb() in event_sched_in() */
2631 * We only want to restart ACTIVE events, so if the event goes
2632 * inactive here (event->oncpu==-1), there's nothing more to do;
2633 * fall through with ret==-ENXIO.
2635 ret = cpu_function_call(READ_ONCE(event->oncpu),
2636 __perf_event_stop, &sd);
2637 } while (ret == -EAGAIN);
2643 * In order to contain the amount of racy and tricky in the address filter
2644 * configuration management, it is a two part process:
2646 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2647 * we update the addresses of corresponding vmas in
2648 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2649 * (p2) when an event is scheduled in (pmu::add), it calls
2650 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2651 * if the generation has changed since the previous call.
2653 * If (p1) happens while the event is active, we restart it to force (p2).
2655 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2656 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2658 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2659 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2661 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2664 void perf_event_addr_filters_sync(struct perf_event *event)
2666 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2668 if (!has_addr_filter(event))
2671 raw_spin_lock(&ifh->lock);
2672 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2673 event->pmu->addr_filters_sync(event);
2674 event->hw.addr_filters_gen = event->addr_filters_gen;
2676 raw_spin_unlock(&ifh->lock);
2678 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2680 static int _perf_event_refresh(struct perf_event *event, int refresh)
2683 * not supported on inherited events
2685 if (event->attr.inherit || !is_sampling_event(event))
2688 atomic_add(refresh, &event->event_limit);
2689 _perf_event_enable(event);
2695 * See perf_event_disable()
2697 int perf_event_refresh(struct perf_event *event, int refresh)
2699 struct perf_event_context *ctx;
2702 ctx = perf_event_ctx_lock(event);
2703 ret = _perf_event_refresh(event, refresh);
2704 perf_event_ctx_unlock(event, ctx);
2708 EXPORT_SYMBOL_GPL(perf_event_refresh);
2710 static void ctx_sched_out(struct perf_event_context *ctx,
2711 struct perf_cpu_context *cpuctx,
2712 enum event_type_t event_type)
2714 int is_active = ctx->is_active;
2715 struct perf_event *event;
2717 lockdep_assert_held(&ctx->lock);
2719 if (likely(!ctx->nr_events)) {
2721 * See __perf_remove_from_context().
2723 WARN_ON_ONCE(ctx->is_active);
2725 WARN_ON_ONCE(cpuctx->task_ctx);
2729 ctx->is_active &= ~event_type;
2730 if (!(ctx->is_active & EVENT_ALL))
2734 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2735 if (!ctx->is_active)
2736 cpuctx->task_ctx = NULL;
2740 * Always update time if it was set; not only when it changes.
2741 * Otherwise we can 'forget' to update time for any but the last
2742 * context we sched out. For example:
2744 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2745 * ctx_sched_out(.event_type = EVENT_PINNED)
2747 * would only update time for the pinned events.
2749 if (is_active & EVENT_TIME) {
2750 /* update (and stop) ctx time */
2751 update_context_time(ctx);
2752 update_cgrp_time_from_cpuctx(cpuctx);
2755 is_active ^= ctx->is_active; /* changed bits */
2757 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2760 perf_pmu_disable(ctx->pmu);
2761 if (is_active & EVENT_PINNED) {
2762 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2763 group_sched_out(event, cpuctx, ctx);
2766 if (is_active & EVENT_FLEXIBLE) {
2767 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2768 group_sched_out(event, cpuctx, ctx);
2770 perf_pmu_enable(ctx->pmu);
2774 * Test whether two contexts are equivalent, i.e. whether they have both been
2775 * cloned from the same version of the same context.
2777 * Equivalence is measured using a generation number in the context that is
2778 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2779 * and list_del_event().
2781 static int context_equiv(struct perf_event_context *ctx1,
2782 struct perf_event_context *ctx2)
2784 lockdep_assert_held(&ctx1->lock);
2785 lockdep_assert_held(&ctx2->lock);
2787 /* Pinning disables the swap optimization */
2788 if (ctx1->pin_count || ctx2->pin_count)
2791 /* If ctx1 is the parent of ctx2 */
2792 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2795 /* If ctx2 is the parent of ctx1 */
2796 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2800 * If ctx1 and ctx2 have the same parent; we flatten the parent
2801 * hierarchy, see perf_event_init_context().
2803 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2804 ctx1->parent_gen == ctx2->parent_gen)
2811 static void __perf_event_sync_stat(struct perf_event *event,
2812 struct perf_event *next_event)
2816 if (!event->attr.inherit_stat)
2820 * Update the event value, we cannot use perf_event_read()
2821 * because we're in the middle of a context switch and have IRQs
2822 * disabled, which upsets smp_call_function_single(), however
2823 * we know the event must be on the current CPU, therefore we
2824 * don't need to use it.
2826 switch (event->state) {
2827 case PERF_EVENT_STATE_ACTIVE:
2828 event->pmu->read(event);
2831 case PERF_EVENT_STATE_INACTIVE:
2832 update_event_times(event);
2840 * In order to keep per-task stats reliable we need to flip the event
2841 * values when we flip the contexts.
2843 value = local64_read(&next_event->count);
2844 value = local64_xchg(&event->count, value);
2845 local64_set(&next_event->count, value);
2847 swap(event->total_time_enabled, next_event->total_time_enabled);
2848 swap(event->total_time_running, next_event->total_time_running);
2851 * Since we swizzled the values, update the user visible data too.
2853 perf_event_update_userpage(event);
2854 perf_event_update_userpage(next_event);
2857 static void perf_event_sync_stat(struct perf_event_context *ctx,
2858 struct perf_event_context *next_ctx)
2860 struct perf_event *event, *next_event;
2865 update_context_time(ctx);
2867 event = list_first_entry(&ctx->event_list,
2868 struct perf_event, event_entry);
2870 next_event = list_first_entry(&next_ctx->event_list,
2871 struct perf_event, event_entry);
2873 while (&event->event_entry != &ctx->event_list &&
2874 &next_event->event_entry != &next_ctx->event_list) {
2876 __perf_event_sync_stat(event, next_event);
2878 event = list_next_entry(event, event_entry);
2879 next_event = list_next_entry(next_event, event_entry);
2883 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2884 struct task_struct *next)
2886 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2887 struct perf_event_context *next_ctx;
2888 struct perf_event_context *parent, *next_parent;
2889 struct perf_cpu_context *cpuctx;
2895 cpuctx = __get_cpu_context(ctx);
2896 if (!cpuctx->task_ctx)
2900 next_ctx = next->perf_event_ctxp[ctxn];
2904 parent = rcu_dereference(ctx->parent_ctx);
2905 next_parent = rcu_dereference(next_ctx->parent_ctx);
2907 /* If neither context have a parent context; they cannot be clones. */
2908 if (!parent && !next_parent)
2911 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2913 * Looks like the two contexts are clones, so we might be
2914 * able to optimize the context switch. We lock both
2915 * contexts and check that they are clones under the
2916 * lock (including re-checking that neither has been
2917 * uncloned in the meantime). It doesn't matter which
2918 * order we take the locks because no other cpu could
2919 * be trying to lock both of these tasks.
2921 raw_spin_lock(&ctx->lock);
2922 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2923 if (context_equiv(ctx, next_ctx)) {
2924 WRITE_ONCE(ctx->task, next);
2925 WRITE_ONCE(next_ctx->task, task);
2927 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2930 * RCU_INIT_POINTER here is safe because we've not
2931 * modified the ctx and the above modification of
2932 * ctx->task and ctx->task_ctx_data are immaterial
2933 * since those values are always verified under
2934 * ctx->lock which we're now holding.
2936 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2937 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2941 perf_event_sync_stat(ctx, next_ctx);
2943 raw_spin_unlock(&next_ctx->lock);
2944 raw_spin_unlock(&ctx->lock);
2950 raw_spin_lock(&ctx->lock);
2951 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2952 raw_spin_unlock(&ctx->lock);
2956 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2958 void perf_sched_cb_dec(struct pmu *pmu)
2960 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2962 this_cpu_dec(perf_sched_cb_usages);
2964 if (!--cpuctx->sched_cb_usage)
2965 list_del(&cpuctx->sched_cb_entry);
2969 void perf_sched_cb_inc(struct pmu *pmu)
2971 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2973 if (!cpuctx->sched_cb_usage++)
2974 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2976 this_cpu_inc(perf_sched_cb_usages);
2980 * This function provides the context switch callback to the lower code
2981 * layer. It is invoked ONLY when the context switch callback is enabled.
2983 * This callback is relevant even to per-cpu events; for example multi event
2984 * PEBS requires this to provide PID/TID information. This requires we flush
2985 * all queued PEBS records before we context switch to a new task.
2987 static void perf_pmu_sched_task(struct task_struct *prev,
2988 struct task_struct *next,
2991 struct perf_cpu_context *cpuctx;
2997 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2998 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3000 if (WARN_ON_ONCE(!pmu->sched_task))
3003 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3004 perf_pmu_disable(pmu);
3006 pmu->sched_task(cpuctx->task_ctx, sched_in);
3008 perf_pmu_enable(pmu);
3009 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3013 static void perf_event_switch(struct task_struct *task,
3014 struct task_struct *next_prev, bool sched_in);
3016 #define for_each_task_context_nr(ctxn) \
3017 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3020 * Called from scheduler to remove the events of the current task,
3021 * with interrupts disabled.
3023 * We stop each event and update the event value in event->count.
3025 * This does not protect us against NMI, but disable()
3026 * sets the disabled bit in the control field of event _before_
3027 * accessing the event control register. If a NMI hits, then it will
3028 * not restart the event.
3030 void __perf_event_task_sched_out(struct task_struct *task,
3031 struct task_struct *next)
3035 if (__this_cpu_read(perf_sched_cb_usages))
3036 perf_pmu_sched_task(task, next, false);
3038 if (atomic_read(&nr_switch_events))
3039 perf_event_switch(task, next, false);
3041 for_each_task_context_nr(ctxn)
3042 perf_event_context_sched_out(task, ctxn, next);
3045 * if cgroup events exist on this CPU, then we need
3046 * to check if we have to switch out PMU state.
3047 * cgroup event are system-wide mode only
3049 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3050 perf_cgroup_sched_out(task, next);
3054 * Called with IRQs disabled
3056 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3057 enum event_type_t event_type)
3059 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3063 ctx_pinned_sched_in(struct perf_event_context *ctx,
3064 struct perf_cpu_context *cpuctx)
3066 struct perf_event *event;
3068 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3069 if (event->state <= PERF_EVENT_STATE_OFF)
3071 if (!event_filter_match(event))
3074 /* may need to reset tstamp_enabled */
3075 if (is_cgroup_event(event))
3076 perf_cgroup_mark_enabled(event, ctx);
3078 if (group_can_go_on(event, cpuctx, 1))
3079 group_sched_in(event, cpuctx, ctx);
3082 * If this pinned group hasn't been scheduled,
3083 * put it in error state.
3085 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3086 update_group_times(event);
3087 event->state = PERF_EVENT_STATE_ERROR;
3093 ctx_flexible_sched_in(struct perf_event_context *ctx,
3094 struct perf_cpu_context *cpuctx)
3096 struct perf_event *event;
3099 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3100 /* Ignore events in OFF or ERROR state */
3101 if (event->state <= PERF_EVENT_STATE_OFF)
3104 * Listen to the 'cpu' scheduling filter constraint
3107 if (!event_filter_match(event))
3110 /* may need to reset tstamp_enabled */
3111 if (is_cgroup_event(event))
3112 perf_cgroup_mark_enabled(event, ctx);
3114 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3115 if (group_sched_in(event, cpuctx, ctx))
3122 ctx_sched_in(struct perf_event_context *ctx,
3123 struct perf_cpu_context *cpuctx,
3124 enum event_type_t event_type,
3125 struct task_struct *task)
3127 int is_active = ctx->is_active;
3130 lockdep_assert_held(&ctx->lock);
3132 if (likely(!ctx->nr_events))
3135 ctx->is_active |= (event_type | EVENT_TIME);
3138 cpuctx->task_ctx = ctx;
3140 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3143 is_active ^= ctx->is_active; /* changed bits */
3145 if (is_active & EVENT_TIME) {
3146 /* start ctx time */
3148 ctx->timestamp = now;
3149 perf_cgroup_set_timestamp(task, ctx);
3153 * First go through the list and put on any pinned groups
3154 * in order to give them the best chance of going on.
3156 if (is_active & EVENT_PINNED)
3157 ctx_pinned_sched_in(ctx, cpuctx);
3159 /* Then walk through the lower prio flexible groups */
3160 if (is_active & EVENT_FLEXIBLE)
3161 ctx_flexible_sched_in(ctx, cpuctx);
3164 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3165 enum event_type_t event_type,
3166 struct task_struct *task)
3168 struct perf_event_context *ctx = &cpuctx->ctx;
3170 ctx_sched_in(ctx, cpuctx, event_type, task);
3173 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3174 struct task_struct *task)
3176 struct perf_cpu_context *cpuctx;
3178 cpuctx = __get_cpu_context(ctx);
3179 if (cpuctx->task_ctx == ctx)
3182 perf_ctx_lock(cpuctx, ctx);
3183 perf_pmu_disable(ctx->pmu);
3185 * We want to keep the following priority order:
3186 * cpu pinned (that don't need to move), task pinned,
3187 * cpu flexible, task flexible.
3189 * However, if task's ctx is not carrying any pinned
3190 * events, no need to flip the cpuctx's events around.
3192 if (!list_empty(&ctx->pinned_groups))
3193 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3194 perf_event_sched_in(cpuctx, ctx, task);
3195 perf_pmu_enable(ctx->pmu);
3196 perf_ctx_unlock(cpuctx, ctx);
3200 * Called from scheduler to add the events of the current task
3201 * with interrupts disabled.
3203 * We restore the event value and then enable it.
3205 * This does not protect us against NMI, but enable()
3206 * sets the enabled bit in the control field of event _before_
3207 * accessing the event control register. If a NMI hits, then it will
3208 * keep the event running.
3210 void __perf_event_task_sched_in(struct task_struct *prev,
3211 struct task_struct *task)
3213 struct perf_event_context *ctx;
3217 * If cgroup events exist on this CPU, then we need to check if we have
3218 * to switch in PMU state; cgroup event are system-wide mode only.
3220 * Since cgroup events are CPU events, we must schedule these in before
3221 * we schedule in the task events.
3223 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3224 perf_cgroup_sched_in(prev, task);
3226 for_each_task_context_nr(ctxn) {
3227 ctx = task->perf_event_ctxp[ctxn];
3231 perf_event_context_sched_in(ctx, task);
3234 if (atomic_read(&nr_switch_events))
3235 perf_event_switch(task, prev, true);
3237 if (__this_cpu_read(perf_sched_cb_usages))
3238 perf_pmu_sched_task(prev, task, true);
3241 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3243 u64 frequency = event->attr.sample_freq;
3244 u64 sec = NSEC_PER_SEC;
3245 u64 divisor, dividend;
3247 int count_fls, nsec_fls, frequency_fls, sec_fls;
3249 count_fls = fls64(count);
3250 nsec_fls = fls64(nsec);
3251 frequency_fls = fls64(frequency);
3255 * We got @count in @nsec, with a target of sample_freq HZ
3256 * the target period becomes:
3259 * period = -------------------
3260 * @nsec * sample_freq
3265 * Reduce accuracy by one bit such that @a and @b converge
3266 * to a similar magnitude.
3268 #define REDUCE_FLS(a, b) \
3270 if (a##_fls > b##_fls) { \
3280 * Reduce accuracy until either term fits in a u64, then proceed with
3281 * the other, so that finally we can do a u64/u64 division.
3283 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3284 REDUCE_FLS(nsec, frequency);
3285 REDUCE_FLS(sec, count);
3288 if (count_fls + sec_fls > 64) {
3289 divisor = nsec * frequency;
3291 while (count_fls + sec_fls > 64) {
3292 REDUCE_FLS(count, sec);
3296 dividend = count * sec;
3298 dividend = count * sec;
3300 while (nsec_fls + frequency_fls > 64) {
3301 REDUCE_FLS(nsec, frequency);
3305 divisor = nsec * frequency;
3311 return div64_u64(dividend, divisor);
3314 static DEFINE_PER_CPU(int, perf_throttled_count);
3315 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3317 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3319 struct hw_perf_event *hwc = &event->hw;
3320 s64 period, sample_period;
3323 period = perf_calculate_period(event, nsec, count);
3325 delta = (s64)(period - hwc->sample_period);
3326 delta = (delta + 7) / 8; /* low pass filter */
3328 sample_period = hwc->sample_period + delta;
3333 hwc->sample_period = sample_period;
3335 if (local64_read(&hwc->period_left) > 8*sample_period) {
3337 event->pmu->stop(event, PERF_EF_UPDATE);
3339 local64_set(&hwc->period_left, 0);
3342 event->pmu->start(event, PERF_EF_RELOAD);
3347 * combine freq adjustment with unthrottling to avoid two passes over the
3348 * events. At the same time, make sure, having freq events does not change
3349 * the rate of unthrottling as that would introduce bias.
3351 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3354 struct perf_event *event;
3355 struct hw_perf_event *hwc;
3356 u64 now, period = TICK_NSEC;
3360 * only need to iterate over all events iff:
3361 * - context have events in frequency mode (needs freq adjust)
3362 * - there are events to unthrottle on this cpu
3364 if (!(ctx->nr_freq || needs_unthr))
3367 raw_spin_lock(&ctx->lock);
3368 perf_pmu_disable(ctx->pmu);
3370 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3371 if (event->state != PERF_EVENT_STATE_ACTIVE)
3374 if (!event_filter_match(event))
3377 perf_pmu_disable(event->pmu);
3381 if (hwc->interrupts == MAX_INTERRUPTS) {
3382 hwc->interrupts = 0;
3383 perf_log_throttle(event, 1);
3384 event->pmu->start(event, 0);
3387 if (!event->attr.freq || !event->attr.sample_freq)
3391 * stop the event and update event->count
3393 event->pmu->stop(event, PERF_EF_UPDATE);
3395 now = local64_read(&event->count);
3396 delta = now - hwc->freq_count_stamp;
3397 hwc->freq_count_stamp = now;
3401 * reload only if value has changed
3402 * we have stopped the event so tell that
3403 * to perf_adjust_period() to avoid stopping it
3407 perf_adjust_period(event, period, delta, false);
3409 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3411 perf_pmu_enable(event->pmu);
3414 perf_pmu_enable(ctx->pmu);
3415 raw_spin_unlock(&ctx->lock);
3419 * Round-robin a context's events:
3421 static void rotate_ctx(struct perf_event_context *ctx)
3424 * Rotate the first entry last of non-pinned groups. Rotation might be
3425 * disabled by the inheritance code.
3427 if (!ctx->rotate_disable)
3428 list_rotate_left(&ctx->flexible_groups);
3431 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3433 struct perf_event_context *ctx = NULL;
3436 if (cpuctx->ctx.nr_events) {
3437 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3441 ctx = cpuctx->task_ctx;
3442 if (ctx && ctx->nr_events) {
3443 if (ctx->nr_events != ctx->nr_active)
3450 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3451 perf_pmu_disable(cpuctx->ctx.pmu);
3453 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3455 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3457 rotate_ctx(&cpuctx->ctx);
3461 perf_event_sched_in(cpuctx, ctx, current);
3463 perf_pmu_enable(cpuctx->ctx.pmu);
3464 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3470 void perf_event_task_tick(void)
3472 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3473 struct perf_event_context *ctx, *tmp;
3476 WARN_ON(!irqs_disabled());
3478 __this_cpu_inc(perf_throttled_seq);
3479 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3480 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3482 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3483 perf_adjust_freq_unthr_context(ctx, throttled);
3486 static int event_enable_on_exec(struct perf_event *event,
3487 struct perf_event_context *ctx)
3489 if (!event->attr.enable_on_exec)
3492 event->attr.enable_on_exec = 0;
3493 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3496 __perf_event_mark_enabled(event);
3502 * Enable all of a task's events that have been marked enable-on-exec.
3503 * This expects task == current.
3505 static void perf_event_enable_on_exec(int ctxn)
3507 struct perf_event_context *ctx, *clone_ctx = NULL;
3508 enum event_type_t event_type = 0;
3509 struct perf_cpu_context *cpuctx;
3510 struct perf_event *event;
3511 unsigned long flags;
3514 local_irq_save(flags);
3515 ctx = current->perf_event_ctxp[ctxn];
3516 if (!ctx || !ctx->nr_events)
3519 cpuctx = __get_cpu_context(ctx);
3520 perf_ctx_lock(cpuctx, ctx);
3521 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3522 list_for_each_entry(event, &ctx->event_list, event_entry) {
3523 enabled |= event_enable_on_exec(event, ctx);
3524 event_type |= get_event_type(event);
3528 * Unclone and reschedule this context if we enabled any event.
3531 clone_ctx = unclone_ctx(ctx);
3532 ctx_resched(cpuctx, ctx, event_type);
3534 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3536 perf_ctx_unlock(cpuctx, ctx);
3539 local_irq_restore(flags);
3545 struct perf_read_data {
3546 struct perf_event *event;
3551 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3553 u16 local_pkg, event_pkg;
3555 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3556 int local_cpu = smp_processor_id();
3558 event_pkg = topology_physical_package_id(event_cpu);
3559 local_pkg = topology_physical_package_id(local_cpu);
3561 if (event_pkg == local_pkg)
3569 * Cross CPU call to read the hardware event
3571 static void __perf_event_read(void *info)
3573 struct perf_read_data *data = info;
3574 struct perf_event *sub, *event = data->event;
3575 struct perf_event_context *ctx = event->ctx;
3576 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3577 struct pmu *pmu = event->pmu;
3580 * If this is a task context, we need to check whether it is
3581 * the current task context of this cpu. If not it has been
3582 * scheduled out before the smp call arrived. In that case
3583 * event->count would have been updated to a recent sample
3584 * when the event was scheduled out.
3586 if (ctx->task && cpuctx->task_ctx != ctx)
3589 raw_spin_lock(&ctx->lock);
3590 if (ctx->is_active) {
3591 update_context_time(ctx);
3592 update_cgrp_time_from_event(event);
3595 update_event_times(event);
3596 if (event->state != PERF_EVENT_STATE_ACTIVE)
3605 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3609 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3610 update_event_times(sub);
3611 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3613 * Use sibling's PMU rather than @event's since
3614 * sibling could be on different (eg: software) PMU.
3616 sub->pmu->read(sub);
3620 data->ret = pmu->commit_txn(pmu);
3623 raw_spin_unlock(&ctx->lock);
3626 static inline u64 perf_event_count(struct perf_event *event)
3628 if (event->pmu->count)
3629 return event->pmu->count(event);
3631 return __perf_event_count(event);
3635 * NMI-safe method to read a local event, that is an event that
3637 * - either for the current task, or for this CPU
3638 * - does not have inherit set, for inherited task events
3639 * will not be local and we cannot read them atomically
3640 * - must not have a pmu::count method
3642 int perf_event_read_local(struct perf_event *event, u64 *value)
3644 unsigned long flags;
3648 * Disabling interrupts avoids all counter scheduling (context
3649 * switches, timer based rotation and IPIs).
3651 local_irq_save(flags);
3654 * It must not be an event with inherit set, we cannot read
3655 * all child counters from atomic context.
3657 if (event->attr.inherit) {
3663 * It must not have a pmu::count method, those are not
3666 if (event->pmu->count) {
3671 /* If this is a per-task event, it must be for current */
3672 if ((event->attach_state & PERF_ATTACH_TASK) &&
3673 event->hw.target != current) {
3678 /* If this is a per-CPU event, it must be for this CPU */
3679 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3680 event->cpu != smp_processor_id()) {
3686 * If the event is currently on this CPU, its either a per-task event,
3687 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3690 if (event->oncpu == smp_processor_id())
3691 event->pmu->read(event);
3693 *value = local64_read(&event->count);
3695 local_irq_restore(flags);
3700 static int perf_event_read(struct perf_event *event, bool group)
3702 int event_cpu, ret = 0;
3705 * If event is enabled and currently active on a CPU, update the
3706 * value in the event structure:
3708 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3709 struct perf_read_data data = {
3715 event_cpu = READ_ONCE(event->oncpu);
3716 if ((unsigned)event_cpu >= nr_cpu_ids)
3720 event_cpu = __perf_event_read_cpu(event, event_cpu);
3723 * Purposely ignore the smp_call_function_single() return
3726 * If event_cpu isn't a valid CPU it means the event got
3727 * scheduled out and that will have updated the event count.
3729 * Therefore, either way, we'll have an up-to-date event count
3732 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3735 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3736 struct perf_event_context *ctx = event->ctx;
3737 unsigned long flags;
3739 raw_spin_lock_irqsave(&ctx->lock, flags);
3741 * may read while context is not active
3742 * (e.g., thread is blocked), in that case
3743 * we cannot update context time
3745 if (ctx->is_active) {
3746 update_context_time(ctx);
3747 update_cgrp_time_from_event(event);
3750 update_group_times(event);
3752 update_event_times(event);
3753 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3760 * Initialize the perf_event context in a task_struct:
3762 static void __perf_event_init_context(struct perf_event_context *ctx)
3764 raw_spin_lock_init(&ctx->lock);
3765 mutex_init(&ctx->mutex);
3766 INIT_LIST_HEAD(&ctx->active_ctx_list);
3767 INIT_LIST_HEAD(&ctx->pinned_groups);
3768 INIT_LIST_HEAD(&ctx->flexible_groups);
3769 INIT_LIST_HEAD(&ctx->event_list);
3770 atomic_set(&ctx->refcount, 1);
3773 static struct perf_event_context *
3774 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3776 struct perf_event_context *ctx;
3778 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3782 __perf_event_init_context(ctx);
3785 get_task_struct(task);
3792 static struct task_struct *
3793 find_lively_task_by_vpid(pid_t vpid)
3795 struct task_struct *task;
3801 task = find_task_by_vpid(vpid);
3803 get_task_struct(task);
3807 return ERR_PTR(-ESRCH);
3813 * Returns a matching context with refcount and pincount.
3815 static struct perf_event_context *
3816 find_get_context(struct pmu *pmu, struct task_struct *task,
3817 struct perf_event *event)
3819 struct perf_event_context *ctx, *clone_ctx = NULL;
3820 struct perf_cpu_context *cpuctx;
3821 void *task_ctx_data = NULL;
3822 unsigned long flags;
3824 int cpu = event->cpu;
3827 /* Must be root to operate on a CPU event: */
3828 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3829 return ERR_PTR(-EACCES);
3831 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3840 ctxn = pmu->task_ctx_nr;
3844 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3845 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3846 if (!task_ctx_data) {
3853 ctx = perf_lock_task_context(task, ctxn, &flags);
3855 clone_ctx = unclone_ctx(ctx);
3858 if (task_ctx_data && !ctx->task_ctx_data) {
3859 ctx->task_ctx_data = task_ctx_data;
3860 task_ctx_data = NULL;
3862 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3867 ctx = alloc_perf_context(pmu, task);
3872 if (task_ctx_data) {
3873 ctx->task_ctx_data = task_ctx_data;
3874 task_ctx_data = NULL;
3878 mutex_lock(&task->perf_event_mutex);
3880 * If it has already passed perf_event_exit_task().
3881 * we must see PF_EXITING, it takes this mutex too.
3883 if (task->flags & PF_EXITING)
3885 else if (task->perf_event_ctxp[ctxn])
3890 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3892 mutex_unlock(&task->perf_event_mutex);
3894 if (unlikely(err)) {
3903 kfree(task_ctx_data);
3907 kfree(task_ctx_data);
3908 return ERR_PTR(err);
3911 static void perf_event_free_filter(struct perf_event *event);
3912 static void perf_event_free_bpf_prog(struct perf_event *event);
3914 static void free_event_rcu(struct rcu_head *head)
3916 struct perf_event *event;
3918 event = container_of(head, struct perf_event, rcu_head);
3920 put_pid_ns(event->ns);
3921 perf_event_free_filter(event);
3925 static void ring_buffer_attach(struct perf_event *event,
3926 struct ring_buffer *rb);
3928 static void detach_sb_event(struct perf_event *event)
3930 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3932 raw_spin_lock(&pel->lock);
3933 list_del_rcu(&event->sb_list);
3934 raw_spin_unlock(&pel->lock);
3937 static bool is_sb_event(struct perf_event *event)
3939 struct perf_event_attr *attr = &event->attr;
3944 if (event->attach_state & PERF_ATTACH_TASK)
3947 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3948 attr->comm || attr->comm_exec ||
3950 attr->context_switch)
3955 static void unaccount_pmu_sb_event(struct perf_event *event)
3957 if (is_sb_event(event))
3958 detach_sb_event(event);
3961 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3966 if (is_cgroup_event(event))
3967 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3970 #ifdef CONFIG_NO_HZ_FULL
3971 static DEFINE_SPINLOCK(nr_freq_lock);
3974 static void unaccount_freq_event_nohz(void)
3976 #ifdef CONFIG_NO_HZ_FULL
3977 spin_lock(&nr_freq_lock);
3978 if (atomic_dec_and_test(&nr_freq_events))
3979 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3980 spin_unlock(&nr_freq_lock);
3984 static void unaccount_freq_event(void)
3986 if (tick_nohz_full_enabled())
3987 unaccount_freq_event_nohz();
3989 atomic_dec(&nr_freq_events);
3992 static void unaccount_event(struct perf_event *event)
3999 if (event->attach_state & PERF_ATTACH_TASK)
4001 if (event->attr.mmap || event->attr.mmap_data)
4002 atomic_dec(&nr_mmap_events);
4003 if (event->attr.comm)
4004 atomic_dec(&nr_comm_events);
4005 if (event->attr.namespaces)
4006 atomic_dec(&nr_namespaces_events);
4007 if (event->attr.task)
4008 atomic_dec(&nr_task_events);
4009 if (event->attr.freq)
4010 unaccount_freq_event();
4011 if (event->attr.context_switch) {
4013 atomic_dec(&nr_switch_events);
4015 if (is_cgroup_event(event))
4017 if (has_branch_stack(event))
4021 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4022 schedule_delayed_work(&perf_sched_work, HZ);
4025 unaccount_event_cpu(event, event->cpu);
4027 unaccount_pmu_sb_event(event);
4030 static void perf_sched_delayed(struct work_struct *work)
4032 mutex_lock(&perf_sched_mutex);
4033 if (atomic_dec_and_test(&perf_sched_count))
4034 static_branch_disable(&perf_sched_events);
4035 mutex_unlock(&perf_sched_mutex);
4039 * The following implement mutual exclusion of events on "exclusive" pmus
4040 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4041 * at a time, so we disallow creating events that might conflict, namely:
4043 * 1) cpu-wide events in the presence of per-task events,
4044 * 2) per-task events in the presence of cpu-wide events,
4045 * 3) two matching events on the same context.
4047 * The former two cases are handled in the allocation path (perf_event_alloc(),
4048 * _free_event()), the latter -- before the first perf_install_in_context().
4050 static int exclusive_event_init(struct perf_event *event)
4052 struct pmu *pmu = event->pmu;
4054 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4058 * Prevent co-existence of per-task and cpu-wide events on the
4059 * same exclusive pmu.
4061 * Negative pmu::exclusive_cnt means there are cpu-wide
4062 * events on this "exclusive" pmu, positive means there are
4065 * Since this is called in perf_event_alloc() path, event::ctx
4066 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4067 * to mean "per-task event", because unlike other attach states it
4068 * never gets cleared.
4070 if (event->attach_state & PERF_ATTACH_TASK) {
4071 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4074 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4081 static void exclusive_event_destroy(struct perf_event *event)
4083 struct pmu *pmu = event->pmu;
4085 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4088 /* see comment in exclusive_event_init() */
4089 if (event->attach_state & PERF_ATTACH_TASK)
4090 atomic_dec(&pmu->exclusive_cnt);
4092 atomic_inc(&pmu->exclusive_cnt);
4095 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4097 if ((e1->pmu == e2->pmu) &&
4098 (e1->cpu == e2->cpu ||
4105 /* Called under the same ctx::mutex as perf_install_in_context() */
4106 static bool exclusive_event_installable(struct perf_event *event,
4107 struct perf_event_context *ctx)
4109 struct perf_event *iter_event;
4110 struct pmu *pmu = event->pmu;
4112 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4115 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4116 if (exclusive_event_match(iter_event, event))
4123 static void perf_addr_filters_splice(struct perf_event *event,
4124 struct list_head *head);
4126 static void _free_event(struct perf_event *event)
4128 irq_work_sync(&event->pending);
4130 unaccount_event(event);
4134 * Can happen when we close an event with re-directed output.
4136 * Since we have a 0 refcount, perf_mmap_close() will skip
4137 * over us; possibly making our ring_buffer_put() the last.
4139 mutex_lock(&event->mmap_mutex);
4140 ring_buffer_attach(event, NULL);
4141 mutex_unlock(&event->mmap_mutex);
4144 if (is_cgroup_event(event))
4145 perf_detach_cgroup(event);
4147 if (!event->parent) {
4148 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4149 put_callchain_buffers();
4152 perf_event_free_bpf_prog(event);
4153 perf_addr_filters_splice(event, NULL);
4154 kfree(event->addr_filters_offs);
4157 event->destroy(event);
4160 put_ctx(event->ctx);
4162 exclusive_event_destroy(event);
4163 module_put(event->pmu->module);
4165 call_rcu(&event->rcu_head, free_event_rcu);
4169 * Used to free events which have a known refcount of 1, such as in error paths
4170 * where the event isn't exposed yet and inherited events.
4172 static void free_event(struct perf_event *event)
4174 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4175 "unexpected event refcount: %ld; ptr=%p\n",
4176 atomic_long_read(&event->refcount), event)) {
4177 /* leak to avoid use-after-free */
4185 * Remove user event from the owner task.
4187 static void perf_remove_from_owner(struct perf_event *event)
4189 struct task_struct *owner;
4193 * Matches the smp_store_release() in perf_event_exit_task(). If we
4194 * observe !owner it means the list deletion is complete and we can
4195 * indeed free this event, otherwise we need to serialize on
4196 * owner->perf_event_mutex.
4198 owner = lockless_dereference(event->owner);
4201 * Since delayed_put_task_struct() also drops the last
4202 * task reference we can safely take a new reference
4203 * while holding the rcu_read_lock().
4205 get_task_struct(owner);
4211 * If we're here through perf_event_exit_task() we're already
4212 * holding ctx->mutex which would be an inversion wrt. the
4213 * normal lock order.
4215 * However we can safely take this lock because its the child
4218 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4221 * We have to re-check the event->owner field, if it is cleared
4222 * we raced with perf_event_exit_task(), acquiring the mutex
4223 * ensured they're done, and we can proceed with freeing the
4227 list_del_init(&event->owner_entry);
4228 smp_store_release(&event->owner, NULL);
4230 mutex_unlock(&owner->perf_event_mutex);
4231 put_task_struct(owner);
4235 static void put_event(struct perf_event *event)
4237 if (!atomic_long_dec_and_test(&event->refcount))
4244 * Kill an event dead; while event:refcount will preserve the event
4245 * object, it will not preserve its functionality. Once the last 'user'
4246 * gives up the object, we'll destroy the thing.
4248 int perf_event_release_kernel(struct perf_event *event)
4250 struct perf_event_context *ctx = event->ctx;
4251 struct perf_event *child, *tmp;
4254 * If we got here through err_file: fput(event_file); we will not have
4255 * attached to a context yet.
4258 WARN_ON_ONCE(event->attach_state &
4259 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4263 if (!is_kernel_event(event))
4264 perf_remove_from_owner(event);
4266 ctx = perf_event_ctx_lock(event);
4267 WARN_ON_ONCE(ctx->parent_ctx);
4268 perf_remove_from_context(event, DETACH_GROUP);
4270 raw_spin_lock_irq(&ctx->lock);
4272 * Mark this event as STATE_DEAD, there is no external reference to it
4275 * Anybody acquiring event->child_mutex after the below loop _must_
4276 * also see this, most importantly inherit_event() which will avoid
4277 * placing more children on the list.
4279 * Thus this guarantees that we will in fact observe and kill _ALL_
4282 event->state = PERF_EVENT_STATE_DEAD;
4283 raw_spin_unlock_irq(&ctx->lock);
4285 perf_event_ctx_unlock(event, ctx);
4288 mutex_lock(&event->child_mutex);
4289 list_for_each_entry(child, &event->child_list, child_list) {
4292 * Cannot change, child events are not migrated, see the
4293 * comment with perf_event_ctx_lock_nested().
4295 ctx = lockless_dereference(child->ctx);
4297 * Since child_mutex nests inside ctx::mutex, we must jump
4298 * through hoops. We start by grabbing a reference on the ctx.
4300 * Since the event cannot get freed while we hold the
4301 * child_mutex, the context must also exist and have a !0
4307 * Now that we have a ctx ref, we can drop child_mutex, and
4308 * acquire ctx::mutex without fear of it going away. Then we
4309 * can re-acquire child_mutex.
4311 mutex_unlock(&event->child_mutex);
4312 mutex_lock(&ctx->mutex);
4313 mutex_lock(&event->child_mutex);
4316 * Now that we hold ctx::mutex and child_mutex, revalidate our
4317 * state, if child is still the first entry, it didn't get freed
4318 * and we can continue doing so.
4320 tmp = list_first_entry_or_null(&event->child_list,
4321 struct perf_event, child_list);
4323 perf_remove_from_context(child, DETACH_GROUP);
4324 list_del(&child->child_list);
4327 * This matches the refcount bump in inherit_event();
4328 * this can't be the last reference.
4333 mutex_unlock(&event->child_mutex);
4334 mutex_unlock(&ctx->mutex);
4338 mutex_unlock(&event->child_mutex);
4341 put_event(event); /* Must be the 'last' reference */
4344 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4347 * Called when the last reference to the file is gone.
4349 static int perf_release(struct inode *inode, struct file *file)
4351 perf_event_release_kernel(file->private_data);
4355 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4357 struct perf_event *child;
4363 mutex_lock(&event->child_mutex);
4365 (void)perf_event_read(event, false);
4366 total += perf_event_count(event);
4368 *enabled += event->total_time_enabled +
4369 atomic64_read(&event->child_total_time_enabled);
4370 *running += event->total_time_running +
4371 atomic64_read(&event->child_total_time_running);
4373 list_for_each_entry(child, &event->child_list, child_list) {
4374 (void)perf_event_read(child, false);
4375 total += perf_event_count(child);
4376 *enabled += child->total_time_enabled;
4377 *running += child->total_time_running;
4379 mutex_unlock(&event->child_mutex);
4383 EXPORT_SYMBOL_GPL(perf_event_read_value);
4385 static int __perf_read_group_add(struct perf_event *leader,
4386 u64 read_format, u64 *values)
4388 struct perf_event_context *ctx = leader->ctx;
4389 struct perf_event *sub;
4390 unsigned long flags;
4391 int n = 1; /* skip @nr */
4394 ret = perf_event_read(leader, true);
4399 * Since we co-schedule groups, {enabled,running} times of siblings
4400 * will be identical to those of the leader, so we only publish one
4403 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4404 values[n++] += leader->total_time_enabled +
4405 atomic64_read(&leader->child_total_time_enabled);
4408 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4409 values[n++] += leader->total_time_running +
4410 atomic64_read(&leader->child_total_time_running);
4414 * Write {count,id} tuples for every sibling.
4416 values[n++] += perf_event_count(leader);
4417 if (read_format & PERF_FORMAT_ID)
4418 values[n++] = primary_event_id(leader);
4420 raw_spin_lock_irqsave(&ctx->lock, flags);
4422 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4423 values[n++] += perf_event_count(sub);
4424 if (read_format & PERF_FORMAT_ID)
4425 values[n++] = primary_event_id(sub);
4428 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4432 static int perf_read_group(struct perf_event *event,
4433 u64 read_format, char __user *buf)
4435 struct perf_event *leader = event->group_leader, *child;
4436 struct perf_event_context *ctx = leader->ctx;
4440 lockdep_assert_held(&ctx->mutex);
4442 values = kzalloc(event->read_size, GFP_KERNEL);
4446 values[0] = 1 + leader->nr_siblings;
4449 * By locking the child_mutex of the leader we effectively
4450 * lock the child list of all siblings.. XXX explain how.
4452 mutex_lock(&leader->child_mutex);
4454 ret = __perf_read_group_add(leader, read_format, values);
4458 list_for_each_entry(child, &leader->child_list, child_list) {
4459 ret = __perf_read_group_add(child, read_format, values);
4464 mutex_unlock(&leader->child_mutex);
4466 ret = event->read_size;
4467 if (copy_to_user(buf, values, event->read_size))
4472 mutex_unlock(&leader->child_mutex);
4478 static int perf_read_one(struct perf_event *event,
4479 u64 read_format, char __user *buf)
4481 u64 enabled, running;
4485 values[n++] = perf_event_read_value(event, &enabled, &running);
4486 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4487 values[n++] = enabled;
4488 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4489 values[n++] = running;
4490 if (read_format & PERF_FORMAT_ID)
4491 values[n++] = primary_event_id(event);
4493 if (copy_to_user(buf, values, n * sizeof(u64)))
4496 return n * sizeof(u64);
4499 static bool is_event_hup(struct perf_event *event)
4503 if (event->state > PERF_EVENT_STATE_EXIT)
4506 mutex_lock(&event->child_mutex);
4507 no_children = list_empty(&event->child_list);
4508 mutex_unlock(&event->child_mutex);
4513 * Read the performance event - simple non blocking version for now
4516 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4518 u64 read_format = event->attr.read_format;
4522 * Return end-of-file for a read on a event that is in
4523 * error state (i.e. because it was pinned but it couldn't be
4524 * scheduled on to the CPU at some point).
4526 if (event->state == PERF_EVENT_STATE_ERROR)
4529 if (count < event->read_size)
4532 WARN_ON_ONCE(event->ctx->parent_ctx);
4533 if (read_format & PERF_FORMAT_GROUP)
4534 ret = perf_read_group(event, read_format, buf);
4536 ret = perf_read_one(event, read_format, buf);
4542 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4544 struct perf_event *event = file->private_data;
4545 struct perf_event_context *ctx;
4548 ctx = perf_event_ctx_lock(event);
4549 ret = __perf_read(event, buf, count);
4550 perf_event_ctx_unlock(event, ctx);
4555 static unsigned int perf_poll(struct file *file, poll_table *wait)
4557 struct perf_event *event = file->private_data;
4558 struct ring_buffer *rb;
4559 unsigned int events = POLLHUP;
4561 poll_wait(file, &event->waitq, wait);
4563 if (is_event_hup(event))
4567 * Pin the event->rb by taking event->mmap_mutex; otherwise
4568 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4570 mutex_lock(&event->mmap_mutex);
4573 events = atomic_xchg(&rb->poll, 0);
4574 mutex_unlock(&event->mmap_mutex);
4578 static void _perf_event_reset(struct perf_event *event)
4580 (void)perf_event_read(event, false);
4581 local64_set(&event->count, 0);
4582 perf_event_update_userpage(event);
4586 * Holding the top-level event's child_mutex means that any
4587 * descendant process that has inherited this event will block
4588 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4589 * task existence requirements of perf_event_enable/disable.
4591 static void perf_event_for_each_child(struct perf_event *event,
4592 void (*func)(struct perf_event *))
4594 struct perf_event *child;
4596 WARN_ON_ONCE(event->ctx->parent_ctx);
4598 mutex_lock(&event->child_mutex);
4600 list_for_each_entry(child, &event->child_list, child_list)
4602 mutex_unlock(&event->child_mutex);
4605 static void perf_event_for_each(struct perf_event *event,
4606 void (*func)(struct perf_event *))
4608 struct perf_event_context *ctx = event->ctx;
4609 struct perf_event *sibling;
4611 lockdep_assert_held(&ctx->mutex);
4613 event = event->group_leader;
4615 perf_event_for_each_child(event, func);
4616 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4617 perf_event_for_each_child(sibling, func);
4620 static void __perf_event_period(struct perf_event *event,
4621 struct perf_cpu_context *cpuctx,
4622 struct perf_event_context *ctx,
4625 u64 value = *((u64 *)info);
4628 if (event->attr.freq) {
4629 event->attr.sample_freq = value;
4631 event->attr.sample_period = value;
4632 event->hw.sample_period = value;
4635 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4637 perf_pmu_disable(ctx->pmu);
4639 * We could be throttled; unthrottle now to avoid the tick
4640 * trying to unthrottle while we already re-started the event.
4642 if (event->hw.interrupts == MAX_INTERRUPTS) {
4643 event->hw.interrupts = 0;
4644 perf_log_throttle(event, 1);
4646 event->pmu->stop(event, PERF_EF_UPDATE);
4649 local64_set(&event->hw.period_left, 0);
4652 event->pmu->start(event, PERF_EF_RELOAD);
4653 perf_pmu_enable(ctx->pmu);
4657 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4661 if (!is_sampling_event(event))
4664 if (copy_from_user(&value, arg, sizeof(value)))
4670 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4673 event_function_call(event, __perf_event_period, &value);
4678 static const struct file_operations perf_fops;
4680 static inline int perf_fget_light(int fd, struct fd *p)
4682 struct fd f = fdget(fd);
4686 if (f.file->f_op != &perf_fops) {
4694 static int perf_event_set_output(struct perf_event *event,
4695 struct perf_event *output_event);
4696 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4697 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4699 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4701 void (*func)(struct perf_event *);
4705 case PERF_EVENT_IOC_ENABLE:
4706 func = _perf_event_enable;
4708 case PERF_EVENT_IOC_DISABLE:
4709 func = _perf_event_disable;
4711 case PERF_EVENT_IOC_RESET:
4712 func = _perf_event_reset;
4715 case PERF_EVENT_IOC_REFRESH:
4716 return _perf_event_refresh(event, arg);
4718 case PERF_EVENT_IOC_PERIOD:
4719 return perf_event_period(event, (u64 __user *)arg);
4721 case PERF_EVENT_IOC_ID:
4723 u64 id = primary_event_id(event);
4725 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4730 case PERF_EVENT_IOC_SET_OUTPUT:
4734 struct perf_event *output_event;
4736 ret = perf_fget_light(arg, &output);
4739 output_event = output.file->private_data;
4740 ret = perf_event_set_output(event, output_event);
4743 ret = perf_event_set_output(event, NULL);
4748 case PERF_EVENT_IOC_SET_FILTER:
4749 return perf_event_set_filter(event, (void __user *)arg);
4751 case PERF_EVENT_IOC_SET_BPF:
4752 return perf_event_set_bpf_prog(event, arg);
4754 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4755 struct ring_buffer *rb;
4758 rb = rcu_dereference(event->rb);
4759 if (!rb || !rb->nr_pages) {
4763 rb_toggle_paused(rb, !!arg);
4771 if (flags & PERF_IOC_FLAG_GROUP)
4772 perf_event_for_each(event, func);
4774 perf_event_for_each_child(event, func);
4779 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4781 struct perf_event *event = file->private_data;
4782 struct perf_event_context *ctx;
4785 ctx = perf_event_ctx_lock(event);
4786 ret = _perf_ioctl(event, cmd, arg);
4787 perf_event_ctx_unlock(event, ctx);
4792 #ifdef CONFIG_COMPAT
4793 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4796 switch (_IOC_NR(cmd)) {
4797 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4798 case _IOC_NR(PERF_EVENT_IOC_ID):
4799 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4800 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4801 cmd &= ~IOCSIZE_MASK;
4802 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4806 return perf_ioctl(file, cmd, arg);
4809 # define perf_compat_ioctl NULL
4812 int perf_event_task_enable(void)
4814 struct perf_event_context *ctx;
4815 struct perf_event *event;
4817 mutex_lock(¤t->perf_event_mutex);
4818 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4819 ctx = perf_event_ctx_lock(event);
4820 perf_event_for_each_child(event, _perf_event_enable);
4821 perf_event_ctx_unlock(event, ctx);
4823 mutex_unlock(¤t->perf_event_mutex);
4828 int perf_event_task_disable(void)
4830 struct perf_event_context *ctx;
4831 struct perf_event *event;
4833 mutex_lock(¤t->perf_event_mutex);
4834 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4835 ctx = perf_event_ctx_lock(event);
4836 perf_event_for_each_child(event, _perf_event_disable);
4837 perf_event_ctx_unlock(event, ctx);
4839 mutex_unlock(¤t->perf_event_mutex);
4844 static int perf_event_index(struct perf_event *event)
4846 if (event->hw.state & PERF_HES_STOPPED)
4849 if (event->state != PERF_EVENT_STATE_ACTIVE)
4852 return event->pmu->event_idx(event);
4855 static void calc_timer_values(struct perf_event *event,
4862 *now = perf_clock();
4863 ctx_time = event->shadow_ctx_time + *now;
4864 *enabled = ctx_time - event->tstamp_enabled;
4865 *running = ctx_time - event->tstamp_running;
4868 static void perf_event_init_userpage(struct perf_event *event)
4870 struct perf_event_mmap_page *userpg;
4871 struct ring_buffer *rb;
4874 rb = rcu_dereference(event->rb);
4878 userpg = rb->user_page;
4880 /* Allow new userspace to detect that bit 0 is deprecated */
4881 userpg->cap_bit0_is_deprecated = 1;
4882 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4883 userpg->data_offset = PAGE_SIZE;
4884 userpg->data_size = perf_data_size(rb);
4890 void __weak arch_perf_update_userpage(
4891 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4896 * Callers need to ensure there can be no nesting of this function, otherwise
4897 * the seqlock logic goes bad. We can not serialize this because the arch
4898 * code calls this from NMI context.
4900 void perf_event_update_userpage(struct perf_event *event)
4902 struct perf_event_mmap_page *userpg;
4903 struct ring_buffer *rb;
4904 u64 enabled, running, now;
4907 rb = rcu_dereference(event->rb);
4912 * compute total_time_enabled, total_time_running
4913 * based on snapshot values taken when the event
4914 * was last scheduled in.
4916 * we cannot simply called update_context_time()
4917 * because of locking issue as we can be called in
4920 calc_timer_values(event, &now, &enabled, &running);
4922 userpg = rb->user_page;
4924 * Disable preemption so as to not let the corresponding user-space
4925 * spin too long if we get preempted.
4930 userpg->index = perf_event_index(event);
4931 userpg->offset = perf_event_count(event);
4933 userpg->offset -= local64_read(&event->hw.prev_count);
4935 userpg->time_enabled = enabled +
4936 atomic64_read(&event->child_total_time_enabled);
4938 userpg->time_running = running +
4939 atomic64_read(&event->child_total_time_running);
4941 arch_perf_update_userpage(event, userpg, now);
4950 static int perf_mmap_fault(struct vm_fault *vmf)
4952 struct perf_event *event = vmf->vma->vm_file->private_data;
4953 struct ring_buffer *rb;
4954 int ret = VM_FAULT_SIGBUS;
4956 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4957 if (vmf->pgoff == 0)
4963 rb = rcu_dereference(event->rb);
4967 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4970 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4974 get_page(vmf->page);
4975 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4976 vmf->page->index = vmf->pgoff;
4985 static void ring_buffer_attach(struct perf_event *event,
4986 struct ring_buffer *rb)
4988 struct ring_buffer *old_rb = NULL;
4989 unsigned long flags;
4993 * Should be impossible, we set this when removing
4994 * event->rb_entry and wait/clear when adding event->rb_entry.
4996 WARN_ON_ONCE(event->rcu_pending);
4999 spin_lock_irqsave(&old_rb->event_lock, flags);
5000 list_del_rcu(&event->rb_entry);
5001 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5003 event->rcu_batches = get_state_synchronize_rcu();
5004 event->rcu_pending = 1;
5008 if (event->rcu_pending) {
5009 cond_synchronize_rcu(event->rcu_batches);
5010 event->rcu_pending = 0;
5013 spin_lock_irqsave(&rb->event_lock, flags);
5014 list_add_rcu(&event->rb_entry, &rb->event_list);
5015 spin_unlock_irqrestore(&rb->event_lock, flags);
5019 * Avoid racing with perf_mmap_close(AUX): stop the event
5020 * before swizzling the event::rb pointer; if it's getting
5021 * unmapped, its aux_mmap_count will be 0 and it won't
5022 * restart. See the comment in __perf_pmu_output_stop().
5024 * Data will inevitably be lost when set_output is done in
5025 * mid-air, but then again, whoever does it like this is
5026 * not in for the data anyway.
5029 perf_event_stop(event, 0);
5031 rcu_assign_pointer(event->rb, rb);
5034 ring_buffer_put(old_rb);
5036 * Since we detached before setting the new rb, so that we
5037 * could attach the new rb, we could have missed a wakeup.
5040 wake_up_all(&event->waitq);
5044 static void ring_buffer_wakeup(struct perf_event *event)
5046 struct ring_buffer *rb;
5049 rb = rcu_dereference(event->rb);
5051 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5052 wake_up_all(&event->waitq);
5057 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5059 struct ring_buffer *rb;
5062 rb = rcu_dereference(event->rb);
5064 if (!atomic_inc_not_zero(&rb->refcount))
5072 void ring_buffer_put(struct ring_buffer *rb)
5074 if (!atomic_dec_and_test(&rb->refcount))
5077 WARN_ON_ONCE(!list_empty(&rb->event_list));
5079 call_rcu(&rb->rcu_head, rb_free_rcu);
5082 static void perf_mmap_open(struct vm_area_struct *vma)
5084 struct perf_event *event = vma->vm_file->private_data;
5086 atomic_inc(&event->mmap_count);
5087 atomic_inc(&event->rb->mmap_count);
5090 atomic_inc(&event->rb->aux_mmap_count);
5092 if (event->pmu->event_mapped)
5093 event->pmu->event_mapped(event);
5096 static void perf_pmu_output_stop(struct perf_event *event);
5099 * A buffer can be mmap()ed multiple times; either directly through the same
5100 * event, or through other events by use of perf_event_set_output().
5102 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5103 * the buffer here, where we still have a VM context. This means we need
5104 * to detach all events redirecting to us.
5106 static void perf_mmap_close(struct vm_area_struct *vma)
5108 struct perf_event *event = vma->vm_file->private_data;
5110 struct ring_buffer *rb = ring_buffer_get(event);
5111 struct user_struct *mmap_user = rb->mmap_user;
5112 int mmap_locked = rb->mmap_locked;
5113 unsigned long size = perf_data_size(rb);
5115 if (event->pmu->event_unmapped)
5116 event->pmu->event_unmapped(event);
5119 * rb->aux_mmap_count will always drop before rb->mmap_count and
5120 * event->mmap_count, so it is ok to use event->mmap_mutex to
5121 * serialize with perf_mmap here.
5123 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5124 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5126 * Stop all AUX events that are writing to this buffer,
5127 * so that we can free its AUX pages and corresponding PMU
5128 * data. Note that after rb::aux_mmap_count dropped to zero,
5129 * they won't start any more (see perf_aux_output_begin()).
5131 perf_pmu_output_stop(event);
5133 /* now it's safe to free the pages */
5134 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5135 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5137 /* this has to be the last one */
5139 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5141 mutex_unlock(&event->mmap_mutex);
5144 atomic_dec(&rb->mmap_count);
5146 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5149 ring_buffer_attach(event, NULL);
5150 mutex_unlock(&event->mmap_mutex);
5152 /* If there's still other mmap()s of this buffer, we're done. */
5153 if (atomic_read(&rb->mmap_count))
5157 * No other mmap()s, detach from all other events that might redirect
5158 * into the now unreachable buffer. Somewhat complicated by the
5159 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5163 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5164 if (!atomic_long_inc_not_zero(&event->refcount)) {
5166 * This event is en-route to free_event() which will
5167 * detach it and remove it from the list.
5173 mutex_lock(&event->mmap_mutex);
5175 * Check we didn't race with perf_event_set_output() which can
5176 * swizzle the rb from under us while we were waiting to
5177 * acquire mmap_mutex.
5179 * If we find a different rb; ignore this event, a next
5180 * iteration will no longer find it on the list. We have to
5181 * still restart the iteration to make sure we're not now
5182 * iterating the wrong list.
5184 if (event->rb == rb)
5185 ring_buffer_attach(event, NULL);
5187 mutex_unlock(&event->mmap_mutex);
5191 * Restart the iteration; either we're on the wrong list or
5192 * destroyed its integrity by doing a deletion.
5199 * It could be there's still a few 0-ref events on the list; they'll
5200 * get cleaned up by free_event() -- they'll also still have their
5201 * ref on the rb and will free it whenever they are done with it.
5203 * Aside from that, this buffer is 'fully' detached and unmapped,
5204 * undo the VM accounting.
5207 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5208 vma->vm_mm->pinned_vm -= mmap_locked;
5209 free_uid(mmap_user);
5212 ring_buffer_put(rb); /* could be last */
5215 static const struct vm_operations_struct perf_mmap_vmops = {
5216 .open = perf_mmap_open,
5217 .close = perf_mmap_close, /* non mergable */
5218 .fault = perf_mmap_fault,
5219 .page_mkwrite = perf_mmap_fault,
5222 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5224 struct perf_event *event = file->private_data;
5225 unsigned long user_locked, user_lock_limit;
5226 struct user_struct *user = current_user();
5227 unsigned long locked, lock_limit;
5228 struct ring_buffer *rb = NULL;
5229 unsigned long vma_size;
5230 unsigned long nr_pages;
5231 long user_extra = 0, extra = 0;
5232 int ret = 0, flags = 0;
5235 * Don't allow mmap() of inherited per-task counters. This would
5236 * create a performance issue due to all children writing to the
5239 if (event->cpu == -1 && event->attr.inherit)
5242 if (!(vma->vm_flags & VM_SHARED))
5245 vma_size = vma->vm_end - vma->vm_start;
5247 if (vma->vm_pgoff == 0) {
5248 nr_pages = (vma_size / PAGE_SIZE) - 1;
5251 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5252 * mapped, all subsequent mappings should have the same size
5253 * and offset. Must be above the normal perf buffer.
5255 u64 aux_offset, aux_size;
5260 nr_pages = vma_size / PAGE_SIZE;
5262 mutex_lock(&event->mmap_mutex);
5269 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5270 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5272 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5275 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5278 /* already mapped with a different offset */
5279 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5282 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5285 /* already mapped with a different size */
5286 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5289 if (!is_power_of_2(nr_pages))
5292 if (!atomic_inc_not_zero(&rb->mmap_count))
5295 if (rb_has_aux(rb)) {
5296 atomic_inc(&rb->aux_mmap_count);
5301 atomic_set(&rb->aux_mmap_count, 1);
5302 user_extra = nr_pages;
5308 * If we have rb pages ensure they're a power-of-two number, so we
5309 * can do bitmasks instead of modulo.
5311 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5314 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5317 WARN_ON_ONCE(event->ctx->parent_ctx);
5319 mutex_lock(&event->mmap_mutex);
5321 if (event->rb->nr_pages != nr_pages) {
5326 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5328 * Raced against perf_mmap_close() through
5329 * perf_event_set_output(). Try again, hope for better
5332 mutex_unlock(&event->mmap_mutex);
5339 user_extra = nr_pages + 1;
5342 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5345 * Increase the limit linearly with more CPUs:
5347 user_lock_limit *= num_online_cpus();
5349 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5351 if (user_locked > user_lock_limit)
5352 extra = user_locked - user_lock_limit;
5354 lock_limit = rlimit(RLIMIT_MEMLOCK);
5355 lock_limit >>= PAGE_SHIFT;
5356 locked = vma->vm_mm->pinned_vm + extra;
5358 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5359 !capable(CAP_IPC_LOCK)) {
5364 WARN_ON(!rb && event->rb);
5366 if (vma->vm_flags & VM_WRITE)
5367 flags |= RING_BUFFER_WRITABLE;
5370 rb = rb_alloc(nr_pages,
5371 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5379 atomic_set(&rb->mmap_count, 1);
5380 rb->mmap_user = get_current_user();
5381 rb->mmap_locked = extra;
5383 ring_buffer_attach(event, rb);
5385 perf_event_init_userpage(event);
5386 perf_event_update_userpage(event);
5388 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5389 event->attr.aux_watermark, flags);
5391 rb->aux_mmap_locked = extra;
5396 atomic_long_add(user_extra, &user->locked_vm);
5397 vma->vm_mm->pinned_vm += extra;
5399 atomic_inc(&event->mmap_count);
5401 atomic_dec(&rb->mmap_count);
5404 mutex_unlock(&event->mmap_mutex);
5407 * Since pinned accounting is per vm we cannot allow fork() to copy our
5410 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5411 vma->vm_ops = &perf_mmap_vmops;
5413 if (event->pmu->event_mapped)
5414 event->pmu->event_mapped(event);
5419 static int perf_fasync(int fd, struct file *filp, int on)
5421 struct inode *inode = file_inode(filp);
5422 struct perf_event *event = filp->private_data;
5426 retval = fasync_helper(fd, filp, on, &event->fasync);
5427 inode_unlock(inode);
5435 static const struct file_operations perf_fops = {
5436 .llseek = no_llseek,
5437 .release = perf_release,
5440 .unlocked_ioctl = perf_ioctl,
5441 .compat_ioctl = perf_compat_ioctl,
5443 .fasync = perf_fasync,
5449 * If there's data, ensure we set the poll() state and publish everything
5450 * to user-space before waking everybody up.
5453 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5455 /* only the parent has fasync state */
5457 event = event->parent;
5458 return &event->fasync;
5461 void perf_event_wakeup(struct perf_event *event)
5463 ring_buffer_wakeup(event);
5465 if (event->pending_kill) {
5466 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5467 event->pending_kill = 0;
5471 static void perf_pending_event(struct irq_work *entry)
5473 struct perf_event *event = container_of(entry,
5474 struct perf_event, pending);
5477 rctx = perf_swevent_get_recursion_context();
5479 * If we 'fail' here, that's OK, it means recursion is already disabled
5480 * and we won't recurse 'further'.
5483 if (event->pending_disable) {
5484 event->pending_disable = 0;
5485 perf_event_disable_local(event);
5488 if (event->pending_wakeup) {
5489 event->pending_wakeup = 0;
5490 perf_event_wakeup(event);
5494 perf_swevent_put_recursion_context(rctx);
5498 * We assume there is only KVM supporting the callbacks.
5499 * Later on, we might change it to a list if there is
5500 * another virtualization implementation supporting the callbacks.
5502 struct perf_guest_info_callbacks *perf_guest_cbs;
5504 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5506 perf_guest_cbs = cbs;
5509 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5511 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5513 perf_guest_cbs = NULL;
5516 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5519 perf_output_sample_regs(struct perf_output_handle *handle,
5520 struct pt_regs *regs, u64 mask)
5523 DECLARE_BITMAP(_mask, 64);
5525 bitmap_from_u64(_mask, mask);
5526 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5529 val = perf_reg_value(regs, bit);
5530 perf_output_put(handle, val);
5534 static void perf_sample_regs_user(struct perf_regs *regs_user,
5535 struct pt_regs *regs,
5536 struct pt_regs *regs_user_copy)
5538 if (user_mode(regs)) {
5539 regs_user->abi = perf_reg_abi(current);
5540 regs_user->regs = regs;
5541 } else if (current->mm) {
5542 perf_get_regs_user(regs_user, regs, regs_user_copy);
5544 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5545 regs_user->regs = NULL;
5549 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5550 struct pt_regs *regs)
5552 regs_intr->regs = regs;
5553 regs_intr->abi = perf_reg_abi(current);
5558 * Get remaining task size from user stack pointer.
5560 * It'd be better to take stack vma map and limit this more
5561 * precisly, but there's no way to get it safely under interrupt,
5562 * so using TASK_SIZE as limit.
5564 static u64 perf_ustack_task_size(struct pt_regs *regs)
5566 unsigned long addr = perf_user_stack_pointer(regs);
5568 if (!addr || addr >= TASK_SIZE)
5571 return TASK_SIZE - addr;
5575 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5576 struct pt_regs *regs)
5580 /* No regs, no stack pointer, no dump. */
5585 * Check if we fit in with the requested stack size into the:
5587 * If we don't, we limit the size to the TASK_SIZE.
5589 * - remaining sample size
5590 * If we don't, we customize the stack size to
5591 * fit in to the remaining sample size.
5594 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5595 stack_size = min(stack_size, (u16) task_size);
5597 /* Current header size plus static size and dynamic size. */
5598 header_size += 2 * sizeof(u64);
5600 /* Do we fit in with the current stack dump size? */
5601 if ((u16) (header_size + stack_size) < header_size) {
5603 * If we overflow the maximum size for the sample,
5604 * we customize the stack dump size to fit in.
5606 stack_size = USHRT_MAX - header_size - sizeof(u64);
5607 stack_size = round_up(stack_size, sizeof(u64));
5614 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5615 struct pt_regs *regs)
5617 /* Case of a kernel thread, nothing to dump */
5620 perf_output_put(handle, size);
5629 * - the size requested by user or the best one we can fit
5630 * in to the sample max size
5632 * - user stack dump data
5634 * - the actual dumped size
5638 perf_output_put(handle, dump_size);
5641 sp = perf_user_stack_pointer(regs);
5642 rem = __output_copy_user(handle, (void *) sp, dump_size);
5643 dyn_size = dump_size - rem;
5645 perf_output_skip(handle, rem);
5648 perf_output_put(handle, dyn_size);
5652 static void __perf_event_header__init_id(struct perf_event_header *header,
5653 struct perf_sample_data *data,
5654 struct perf_event *event)
5656 u64 sample_type = event->attr.sample_type;
5658 data->type = sample_type;
5659 header->size += event->id_header_size;
5661 if (sample_type & PERF_SAMPLE_TID) {
5662 /* namespace issues */
5663 data->tid_entry.pid = perf_event_pid(event, current);
5664 data->tid_entry.tid = perf_event_tid(event, current);
5667 if (sample_type & PERF_SAMPLE_TIME)
5668 data->time = perf_event_clock(event);
5670 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5671 data->id = primary_event_id(event);
5673 if (sample_type & PERF_SAMPLE_STREAM_ID)
5674 data->stream_id = event->id;
5676 if (sample_type & PERF_SAMPLE_CPU) {
5677 data->cpu_entry.cpu = raw_smp_processor_id();
5678 data->cpu_entry.reserved = 0;
5682 void perf_event_header__init_id(struct perf_event_header *header,
5683 struct perf_sample_data *data,
5684 struct perf_event *event)
5686 if (event->attr.sample_id_all)
5687 __perf_event_header__init_id(header, data, event);
5690 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5691 struct perf_sample_data *data)
5693 u64 sample_type = data->type;
5695 if (sample_type & PERF_SAMPLE_TID)
5696 perf_output_put(handle, data->tid_entry);
5698 if (sample_type & PERF_SAMPLE_TIME)
5699 perf_output_put(handle, data->time);
5701 if (sample_type & PERF_SAMPLE_ID)
5702 perf_output_put(handle, data->id);
5704 if (sample_type & PERF_SAMPLE_STREAM_ID)
5705 perf_output_put(handle, data->stream_id);
5707 if (sample_type & PERF_SAMPLE_CPU)
5708 perf_output_put(handle, data->cpu_entry);
5710 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5711 perf_output_put(handle, data->id);
5714 void perf_event__output_id_sample(struct perf_event *event,
5715 struct perf_output_handle *handle,
5716 struct perf_sample_data *sample)
5718 if (event->attr.sample_id_all)
5719 __perf_event__output_id_sample(handle, sample);
5722 static void perf_output_read_one(struct perf_output_handle *handle,
5723 struct perf_event *event,
5724 u64 enabled, u64 running)
5726 u64 read_format = event->attr.read_format;
5730 values[n++] = perf_event_count(event);
5731 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5732 values[n++] = enabled +
5733 atomic64_read(&event->child_total_time_enabled);
5735 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5736 values[n++] = running +
5737 atomic64_read(&event->child_total_time_running);
5739 if (read_format & PERF_FORMAT_ID)
5740 values[n++] = primary_event_id(event);
5742 __output_copy(handle, values, n * sizeof(u64));
5745 static void perf_output_read_group(struct perf_output_handle *handle,
5746 struct perf_event *event,
5747 u64 enabled, u64 running)
5749 struct perf_event *leader = event->group_leader, *sub;
5750 u64 read_format = event->attr.read_format;
5754 values[n++] = 1 + leader->nr_siblings;
5756 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5757 values[n++] = enabled;
5759 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5760 values[n++] = running;
5762 if (leader != event)
5763 leader->pmu->read(leader);
5765 values[n++] = perf_event_count(leader);
5766 if (read_format & PERF_FORMAT_ID)
5767 values[n++] = primary_event_id(leader);
5769 __output_copy(handle, values, n * sizeof(u64));
5771 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5774 if ((sub != event) &&
5775 (sub->state == PERF_EVENT_STATE_ACTIVE))
5776 sub->pmu->read(sub);
5778 values[n++] = perf_event_count(sub);
5779 if (read_format & PERF_FORMAT_ID)
5780 values[n++] = primary_event_id(sub);
5782 __output_copy(handle, values, n * sizeof(u64));
5786 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5787 PERF_FORMAT_TOTAL_TIME_RUNNING)
5790 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5792 * The problem is that its both hard and excessively expensive to iterate the
5793 * child list, not to mention that its impossible to IPI the children running
5794 * on another CPU, from interrupt/NMI context.
5796 static void perf_output_read(struct perf_output_handle *handle,
5797 struct perf_event *event)
5799 u64 enabled = 0, running = 0, now;
5800 u64 read_format = event->attr.read_format;
5803 * compute total_time_enabled, total_time_running
5804 * based on snapshot values taken when the event
5805 * was last scheduled in.
5807 * we cannot simply called update_context_time()
5808 * because of locking issue as we are called in
5811 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5812 calc_timer_values(event, &now, &enabled, &running);
5814 if (event->attr.read_format & PERF_FORMAT_GROUP)
5815 perf_output_read_group(handle, event, enabled, running);
5817 perf_output_read_one(handle, event, enabled, running);
5820 void perf_output_sample(struct perf_output_handle *handle,
5821 struct perf_event_header *header,
5822 struct perf_sample_data *data,
5823 struct perf_event *event)
5825 u64 sample_type = data->type;
5827 perf_output_put(handle, *header);
5829 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5830 perf_output_put(handle, data->id);
5832 if (sample_type & PERF_SAMPLE_IP)
5833 perf_output_put(handle, data->ip);
5835 if (sample_type & PERF_SAMPLE_TID)
5836 perf_output_put(handle, data->tid_entry);
5838 if (sample_type & PERF_SAMPLE_TIME)
5839 perf_output_put(handle, data->time);
5841 if (sample_type & PERF_SAMPLE_ADDR)
5842 perf_output_put(handle, data->addr);
5844 if (sample_type & PERF_SAMPLE_ID)
5845 perf_output_put(handle, data->id);
5847 if (sample_type & PERF_SAMPLE_STREAM_ID)
5848 perf_output_put(handle, data->stream_id);
5850 if (sample_type & PERF_SAMPLE_CPU)
5851 perf_output_put(handle, data->cpu_entry);
5853 if (sample_type & PERF_SAMPLE_PERIOD)
5854 perf_output_put(handle, data->period);
5856 if (sample_type & PERF_SAMPLE_READ)
5857 perf_output_read(handle, event);
5859 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5860 if (data->callchain) {
5863 if (data->callchain)
5864 size += data->callchain->nr;
5866 size *= sizeof(u64);
5868 __output_copy(handle, data->callchain, size);
5871 perf_output_put(handle, nr);
5875 if (sample_type & PERF_SAMPLE_RAW) {
5876 struct perf_raw_record *raw = data->raw;
5879 struct perf_raw_frag *frag = &raw->frag;
5881 perf_output_put(handle, raw->size);
5884 __output_custom(handle, frag->copy,
5885 frag->data, frag->size);
5887 __output_copy(handle, frag->data,
5890 if (perf_raw_frag_last(frag))
5895 __output_skip(handle, NULL, frag->pad);
5901 .size = sizeof(u32),
5904 perf_output_put(handle, raw);
5908 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5909 if (data->br_stack) {
5912 size = data->br_stack->nr
5913 * sizeof(struct perf_branch_entry);
5915 perf_output_put(handle, data->br_stack->nr);
5916 perf_output_copy(handle, data->br_stack->entries, size);
5919 * we always store at least the value of nr
5922 perf_output_put(handle, nr);
5926 if (sample_type & PERF_SAMPLE_REGS_USER) {
5927 u64 abi = data->regs_user.abi;
5930 * If there are no regs to dump, notice it through
5931 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5933 perf_output_put(handle, abi);
5936 u64 mask = event->attr.sample_regs_user;
5937 perf_output_sample_regs(handle,
5938 data->regs_user.regs,
5943 if (sample_type & PERF_SAMPLE_STACK_USER) {
5944 perf_output_sample_ustack(handle,
5945 data->stack_user_size,
5946 data->regs_user.regs);
5949 if (sample_type & PERF_SAMPLE_WEIGHT)
5950 perf_output_put(handle, data->weight);
5952 if (sample_type & PERF_SAMPLE_DATA_SRC)
5953 perf_output_put(handle, data->data_src.val);
5955 if (sample_type & PERF_SAMPLE_TRANSACTION)
5956 perf_output_put(handle, data->txn);
5958 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5959 u64 abi = data->regs_intr.abi;
5961 * If there are no regs to dump, notice it through
5962 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5964 perf_output_put(handle, abi);
5967 u64 mask = event->attr.sample_regs_intr;
5969 perf_output_sample_regs(handle,
5970 data->regs_intr.regs,
5975 if (!event->attr.watermark) {
5976 int wakeup_events = event->attr.wakeup_events;
5978 if (wakeup_events) {
5979 struct ring_buffer *rb = handle->rb;
5980 int events = local_inc_return(&rb->events);
5982 if (events >= wakeup_events) {
5983 local_sub(wakeup_events, &rb->events);
5984 local_inc(&rb->wakeup);
5990 void perf_prepare_sample(struct perf_event_header *header,
5991 struct perf_sample_data *data,
5992 struct perf_event *event,
5993 struct pt_regs *regs)
5995 u64 sample_type = event->attr.sample_type;
5997 header->type = PERF_RECORD_SAMPLE;
5998 header->size = sizeof(*header) + event->header_size;
6001 header->misc |= perf_misc_flags(regs);
6003 __perf_event_header__init_id(header, data, event);
6005 if (sample_type & PERF_SAMPLE_IP)
6006 data->ip = perf_instruction_pointer(regs);
6008 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6011 data->callchain = perf_callchain(event, regs);
6013 if (data->callchain)
6014 size += data->callchain->nr;
6016 header->size += size * sizeof(u64);
6019 if (sample_type & PERF_SAMPLE_RAW) {
6020 struct perf_raw_record *raw = data->raw;
6024 struct perf_raw_frag *frag = &raw->frag;
6029 if (perf_raw_frag_last(frag))
6034 size = round_up(sum + sizeof(u32), sizeof(u64));
6035 raw->size = size - sizeof(u32);
6036 frag->pad = raw->size - sum;
6041 header->size += size;
6044 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6045 int size = sizeof(u64); /* nr */
6046 if (data->br_stack) {
6047 size += data->br_stack->nr
6048 * sizeof(struct perf_branch_entry);
6050 header->size += size;
6053 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6054 perf_sample_regs_user(&data->regs_user, regs,
6055 &data->regs_user_copy);
6057 if (sample_type & PERF_SAMPLE_REGS_USER) {
6058 /* regs dump ABI info */
6059 int size = sizeof(u64);
6061 if (data->regs_user.regs) {
6062 u64 mask = event->attr.sample_regs_user;
6063 size += hweight64(mask) * sizeof(u64);
6066 header->size += size;
6069 if (sample_type & PERF_SAMPLE_STACK_USER) {
6071 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6072 * processed as the last one or have additional check added
6073 * in case new sample type is added, because we could eat
6074 * up the rest of the sample size.
6076 u16 stack_size = event->attr.sample_stack_user;
6077 u16 size = sizeof(u64);
6079 stack_size = perf_sample_ustack_size(stack_size, header->size,
6080 data->regs_user.regs);
6083 * If there is something to dump, add space for the dump
6084 * itself and for the field that tells the dynamic size,
6085 * which is how many have been actually dumped.
6088 size += sizeof(u64) + stack_size;
6090 data->stack_user_size = stack_size;
6091 header->size += size;
6094 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6095 /* regs dump ABI info */
6096 int size = sizeof(u64);
6098 perf_sample_regs_intr(&data->regs_intr, regs);
6100 if (data->regs_intr.regs) {
6101 u64 mask = event->attr.sample_regs_intr;
6103 size += hweight64(mask) * sizeof(u64);
6106 header->size += size;
6110 static void __always_inline
6111 __perf_event_output(struct perf_event *event,
6112 struct perf_sample_data *data,
6113 struct pt_regs *regs,
6114 int (*output_begin)(struct perf_output_handle *,
6115 struct perf_event *,
6118 struct perf_output_handle handle;
6119 struct perf_event_header header;
6121 /* protect the callchain buffers */
6124 perf_prepare_sample(&header, data, event, regs);
6126 if (output_begin(&handle, event, header.size))
6129 perf_output_sample(&handle, &header, data, event);
6131 perf_output_end(&handle);
6138 perf_event_output_forward(struct perf_event *event,
6139 struct perf_sample_data *data,
6140 struct pt_regs *regs)
6142 __perf_event_output(event, data, regs, perf_output_begin_forward);
6146 perf_event_output_backward(struct perf_event *event,
6147 struct perf_sample_data *data,
6148 struct pt_regs *regs)
6150 __perf_event_output(event, data, regs, perf_output_begin_backward);
6154 perf_event_output(struct perf_event *event,
6155 struct perf_sample_data *data,
6156 struct pt_regs *regs)
6158 __perf_event_output(event, data, regs, perf_output_begin);
6165 struct perf_read_event {
6166 struct perf_event_header header;
6173 perf_event_read_event(struct perf_event *event,
6174 struct task_struct *task)
6176 struct perf_output_handle handle;
6177 struct perf_sample_data sample;
6178 struct perf_read_event read_event = {
6180 .type = PERF_RECORD_READ,
6182 .size = sizeof(read_event) + event->read_size,
6184 .pid = perf_event_pid(event, task),
6185 .tid = perf_event_tid(event, task),
6189 perf_event_header__init_id(&read_event.header, &sample, event);
6190 ret = perf_output_begin(&handle, event, read_event.header.size);
6194 perf_output_put(&handle, read_event);
6195 perf_output_read(&handle, event);
6196 perf_event__output_id_sample(event, &handle, &sample);
6198 perf_output_end(&handle);
6201 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6204 perf_iterate_ctx(struct perf_event_context *ctx,
6205 perf_iterate_f output,
6206 void *data, bool all)
6208 struct perf_event *event;
6210 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6212 if (event->state < PERF_EVENT_STATE_INACTIVE)
6214 if (!event_filter_match(event))
6218 output(event, data);
6222 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6224 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6225 struct perf_event *event;
6227 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6229 * Skip events that are not fully formed yet; ensure that
6230 * if we observe event->ctx, both event and ctx will be
6231 * complete enough. See perf_install_in_context().
6233 if (!smp_load_acquire(&event->ctx))
6236 if (event->state < PERF_EVENT_STATE_INACTIVE)
6238 if (!event_filter_match(event))
6240 output(event, data);
6245 * Iterate all events that need to receive side-band events.
6247 * For new callers; ensure that account_pmu_sb_event() includes
6248 * your event, otherwise it might not get delivered.
6251 perf_iterate_sb(perf_iterate_f output, void *data,
6252 struct perf_event_context *task_ctx)
6254 struct perf_event_context *ctx;
6261 * If we have task_ctx != NULL we only notify the task context itself.
6262 * The task_ctx is set only for EXIT events before releasing task
6266 perf_iterate_ctx(task_ctx, output, data, false);
6270 perf_iterate_sb_cpu(output, data);
6272 for_each_task_context_nr(ctxn) {
6273 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6275 perf_iterate_ctx(ctx, output, data, false);
6283 * Clear all file-based filters at exec, they'll have to be
6284 * re-instated when/if these objects are mmapped again.
6286 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6288 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6289 struct perf_addr_filter *filter;
6290 unsigned int restart = 0, count = 0;
6291 unsigned long flags;
6293 if (!has_addr_filter(event))
6296 raw_spin_lock_irqsave(&ifh->lock, flags);
6297 list_for_each_entry(filter, &ifh->list, entry) {
6298 if (filter->inode) {
6299 event->addr_filters_offs[count] = 0;
6307 event->addr_filters_gen++;
6308 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6311 perf_event_stop(event, 1);
6314 void perf_event_exec(void)
6316 struct perf_event_context *ctx;
6320 for_each_task_context_nr(ctxn) {
6321 ctx = current->perf_event_ctxp[ctxn];
6325 perf_event_enable_on_exec(ctxn);
6327 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6333 struct remote_output {
6334 struct ring_buffer *rb;
6338 static void __perf_event_output_stop(struct perf_event *event, void *data)
6340 struct perf_event *parent = event->parent;
6341 struct remote_output *ro = data;
6342 struct ring_buffer *rb = ro->rb;
6343 struct stop_event_data sd = {
6347 if (!has_aux(event))
6354 * In case of inheritance, it will be the parent that links to the
6355 * ring-buffer, but it will be the child that's actually using it.
6357 * We are using event::rb to determine if the event should be stopped,
6358 * however this may race with ring_buffer_attach() (through set_output),
6359 * which will make us skip the event that actually needs to be stopped.
6360 * So ring_buffer_attach() has to stop an aux event before re-assigning
6363 if (rcu_dereference(parent->rb) == rb)
6364 ro->err = __perf_event_stop(&sd);
6367 static int __perf_pmu_output_stop(void *info)
6369 struct perf_event *event = info;
6370 struct pmu *pmu = event->pmu;
6371 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6372 struct remote_output ro = {
6377 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6378 if (cpuctx->task_ctx)
6379 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6386 static void perf_pmu_output_stop(struct perf_event *event)
6388 struct perf_event *iter;
6393 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6395 * For per-CPU events, we need to make sure that neither they
6396 * nor their children are running; for cpu==-1 events it's
6397 * sufficient to stop the event itself if it's active, since
6398 * it can't have children.
6402 cpu = READ_ONCE(iter->oncpu);
6407 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6408 if (err == -EAGAIN) {
6417 * task tracking -- fork/exit
6419 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6422 struct perf_task_event {
6423 struct task_struct *task;
6424 struct perf_event_context *task_ctx;
6427 struct perf_event_header header;
6437 static int perf_event_task_match(struct perf_event *event)
6439 return event->attr.comm || event->attr.mmap ||
6440 event->attr.mmap2 || event->attr.mmap_data ||
6444 static void perf_event_task_output(struct perf_event *event,
6447 struct perf_task_event *task_event = data;
6448 struct perf_output_handle handle;
6449 struct perf_sample_data sample;
6450 struct task_struct *task = task_event->task;
6451 int ret, size = task_event->event_id.header.size;
6453 if (!perf_event_task_match(event))
6456 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6458 ret = perf_output_begin(&handle, event,
6459 task_event->event_id.header.size);
6463 task_event->event_id.pid = perf_event_pid(event, task);
6464 task_event->event_id.ppid = perf_event_pid(event, current);
6466 task_event->event_id.tid = perf_event_tid(event, task);
6467 task_event->event_id.ptid = perf_event_tid(event, current);
6469 task_event->event_id.time = perf_event_clock(event);
6471 perf_output_put(&handle, task_event->event_id);
6473 perf_event__output_id_sample(event, &handle, &sample);
6475 perf_output_end(&handle);
6477 task_event->event_id.header.size = size;
6480 static void perf_event_task(struct task_struct *task,
6481 struct perf_event_context *task_ctx,
6484 struct perf_task_event task_event;
6486 if (!atomic_read(&nr_comm_events) &&
6487 !atomic_read(&nr_mmap_events) &&
6488 !atomic_read(&nr_task_events))
6491 task_event = (struct perf_task_event){
6493 .task_ctx = task_ctx,
6496 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6498 .size = sizeof(task_event.event_id),
6508 perf_iterate_sb(perf_event_task_output,
6513 void perf_event_fork(struct task_struct *task)
6515 perf_event_task(task, NULL, 1);
6516 perf_event_namespaces(task);
6523 struct perf_comm_event {
6524 struct task_struct *task;
6529 struct perf_event_header header;
6536 static int perf_event_comm_match(struct perf_event *event)
6538 return event->attr.comm;
6541 static void perf_event_comm_output(struct perf_event *event,
6544 struct perf_comm_event *comm_event = data;
6545 struct perf_output_handle handle;
6546 struct perf_sample_data sample;
6547 int size = comm_event->event_id.header.size;
6550 if (!perf_event_comm_match(event))
6553 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6554 ret = perf_output_begin(&handle, event,
6555 comm_event->event_id.header.size);
6560 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6561 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6563 perf_output_put(&handle, comm_event->event_id);
6564 __output_copy(&handle, comm_event->comm,
6565 comm_event->comm_size);
6567 perf_event__output_id_sample(event, &handle, &sample);
6569 perf_output_end(&handle);
6571 comm_event->event_id.header.size = size;
6574 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6576 char comm[TASK_COMM_LEN];
6579 memset(comm, 0, sizeof(comm));
6580 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6581 size = ALIGN(strlen(comm)+1, sizeof(u64));
6583 comm_event->comm = comm;
6584 comm_event->comm_size = size;
6586 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6588 perf_iterate_sb(perf_event_comm_output,
6593 void perf_event_comm(struct task_struct *task, bool exec)
6595 struct perf_comm_event comm_event;
6597 if (!atomic_read(&nr_comm_events))
6600 comm_event = (struct perf_comm_event){
6606 .type = PERF_RECORD_COMM,
6607 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6615 perf_event_comm_event(&comm_event);
6619 * namespaces tracking
6622 struct perf_namespaces_event {
6623 struct task_struct *task;
6626 struct perf_event_header header;
6631 struct perf_ns_link_info link_info[NR_NAMESPACES];
6635 static int perf_event_namespaces_match(struct perf_event *event)
6637 return event->attr.namespaces;
6640 static void perf_event_namespaces_output(struct perf_event *event,
6643 struct perf_namespaces_event *namespaces_event = data;
6644 struct perf_output_handle handle;
6645 struct perf_sample_data sample;
6648 if (!perf_event_namespaces_match(event))
6651 perf_event_header__init_id(&namespaces_event->event_id.header,
6653 ret = perf_output_begin(&handle, event,
6654 namespaces_event->event_id.header.size);
6658 namespaces_event->event_id.pid = perf_event_pid(event,
6659 namespaces_event->task);
6660 namespaces_event->event_id.tid = perf_event_tid(event,
6661 namespaces_event->task);
6663 perf_output_put(&handle, namespaces_event->event_id);
6665 perf_event__output_id_sample(event, &handle, &sample);
6667 perf_output_end(&handle);
6670 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6671 struct task_struct *task,
6672 const struct proc_ns_operations *ns_ops)
6674 struct path ns_path;
6675 struct inode *ns_inode;
6678 error = ns_get_path(&ns_path, task, ns_ops);
6680 ns_inode = ns_path.dentry->d_inode;
6681 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6682 ns_link_info->ino = ns_inode->i_ino;
6686 void perf_event_namespaces(struct task_struct *task)
6688 struct perf_namespaces_event namespaces_event;
6689 struct perf_ns_link_info *ns_link_info;
6691 if (!atomic_read(&nr_namespaces_events))
6694 namespaces_event = (struct perf_namespaces_event){
6698 .type = PERF_RECORD_NAMESPACES,
6700 .size = sizeof(namespaces_event.event_id),
6704 .nr_namespaces = NR_NAMESPACES,
6705 /* .link_info[NR_NAMESPACES] */
6709 ns_link_info = namespaces_event.event_id.link_info;
6711 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6712 task, &mntns_operations);
6714 #ifdef CONFIG_USER_NS
6715 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6716 task, &userns_operations);
6718 #ifdef CONFIG_NET_NS
6719 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6720 task, &netns_operations);
6722 #ifdef CONFIG_UTS_NS
6723 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6724 task, &utsns_operations);
6726 #ifdef CONFIG_IPC_NS
6727 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6728 task, &ipcns_operations);
6730 #ifdef CONFIG_PID_NS
6731 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6732 task, &pidns_operations);
6734 #ifdef CONFIG_CGROUPS
6735 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6736 task, &cgroupns_operations);
6739 perf_iterate_sb(perf_event_namespaces_output,
6748 struct perf_mmap_event {
6749 struct vm_area_struct *vma;
6751 const char *file_name;
6759 struct perf_event_header header;
6769 static int perf_event_mmap_match(struct perf_event *event,
6772 struct perf_mmap_event *mmap_event = data;
6773 struct vm_area_struct *vma = mmap_event->vma;
6774 int executable = vma->vm_flags & VM_EXEC;
6776 return (!executable && event->attr.mmap_data) ||
6777 (executable && (event->attr.mmap || event->attr.mmap2));
6780 static void perf_event_mmap_output(struct perf_event *event,
6783 struct perf_mmap_event *mmap_event = data;
6784 struct perf_output_handle handle;
6785 struct perf_sample_data sample;
6786 int size = mmap_event->event_id.header.size;
6789 if (!perf_event_mmap_match(event, data))
6792 if (event->attr.mmap2) {
6793 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6794 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6795 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6796 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6797 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6798 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6799 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6802 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6803 ret = perf_output_begin(&handle, event,
6804 mmap_event->event_id.header.size);
6808 mmap_event->event_id.pid = perf_event_pid(event, current);
6809 mmap_event->event_id.tid = perf_event_tid(event, current);
6811 perf_output_put(&handle, mmap_event->event_id);
6813 if (event->attr.mmap2) {
6814 perf_output_put(&handle, mmap_event->maj);
6815 perf_output_put(&handle, mmap_event->min);
6816 perf_output_put(&handle, mmap_event->ino);
6817 perf_output_put(&handle, mmap_event->ino_generation);
6818 perf_output_put(&handle, mmap_event->prot);
6819 perf_output_put(&handle, mmap_event->flags);
6822 __output_copy(&handle, mmap_event->file_name,
6823 mmap_event->file_size);
6825 perf_event__output_id_sample(event, &handle, &sample);
6827 perf_output_end(&handle);
6829 mmap_event->event_id.header.size = size;
6832 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6834 struct vm_area_struct *vma = mmap_event->vma;
6835 struct file *file = vma->vm_file;
6836 int maj = 0, min = 0;
6837 u64 ino = 0, gen = 0;
6838 u32 prot = 0, flags = 0;
6844 if (vma->vm_flags & VM_READ)
6846 if (vma->vm_flags & VM_WRITE)
6848 if (vma->vm_flags & VM_EXEC)
6851 if (vma->vm_flags & VM_MAYSHARE)
6854 flags = MAP_PRIVATE;
6856 if (vma->vm_flags & VM_DENYWRITE)
6857 flags |= MAP_DENYWRITE;
6858 if (vma->vm_flags & VM_MAYEXEC)
6859 flags |= MAP_EXECUTABLE;
6860 if (vma->vm_flags & VM_LOCKED)
6861 flags |= MAP_LOCKED;
6862 if (vma->vm_flags & VM_HUGETLB)
6863 flags |= MAP_HUGETLB;
6866 struct inode *inode;
6869 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6875 * d_path() works from the end of the rb backwards, so we
6876 * need to add enough zero bytes after the string to handle
6877 * the 64bit alignment we do later.
6879 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6884 inode = file_inode(vma->vm_file);
6885 dev = inode->i_sb->s_dev;
6887 gen = inode->i_generation;
6893 if (vma->vm_ops && vma->vm_ops->name) {
6894 name = (char *) vma->vm_ops->name(vma);
6899 name = (char *)arch_vma_name(vma);
6903 if (vma->vm_start <= vma->vm_mm->start_brk &&
6904 vma->vm_end >= vma->vm_mm->brk) {
6908 if (vma->vm_start <= vma->vm_mm->start_stack &&
6909 vma->vm_end >= vma->vm_mm->start_stack) {
6919 strlcpy(tmp, name, sizeof(tmp));
6923 * Since our buffer works in 8 byte units we need to align our string
6924 * size to a multiple of 8. However, we must guarantee the tail end is
6925 * zero'd out to avoid leaking random bits to userspace.
6927 size = strlen(name)+1;
6928 while (!IS_ALIGNED(size, sizeof(u64)))
6929 name[size++] = '\0';
6931 mmap_event->file_name = name;
6932 mmap_event->file_size = size;
6933 mmap_event->maj = maj;
6934 mmap_event->min = min;
6935 mmap_event->ino = ino;
6936 mmap_event->ino_generation = gen;
6937 mmap_event->prot = prot;
6938 mmap_event->flags = flags;
6940 if (!(vma->vm_flags & VM_EXEC))
6941 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6943 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6945 perf_iterate_sb(perf_event_mmap_output,
6953 * Check whether inode and address range match filter criteria.
6955 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6956 struct file *file, unsigned long offset,
6959 if (filter->inode != file_inode(file))
6962 if (filter->offset > offset + size)
6965 if (filter->offset + filter->size < offset)
6971 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6973 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6974 struct vm_area_struct *vma = data;
6975 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6976 struct file *file = vma->vm_file;
6977 struct perf_addr_filter *filter;
6978 unsigned int restart = 0, count = 0;
6980 if (!has_addr_filter(event))
6986 raw_spin_lock_irqsave(&ifh->lock, flags);
6987 list_for_each_entry(filter, &ifh->list, entry) {
6988 if (perf_addr_filter_match(filter, file, off,
6989 vma->vm_end - vma->vm_start)) {
6990 event->addr_filters_offs[count] = vma->vm_start;
6998 event->addr_filters_gen++;
6999 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7002 perf_event_stop(event, 1);
7006 * Adjust all task's events' filters to the new vma
7008 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7010 struct perf_event_context *ctx;
7014 * Data tracing isn't supported yet and as such there is no need
7015 * to keep track of anything that isn't related to executable code:
7017 if (!(vma->vm_flags & VM_EXEC))
7021 for_each_task_context_nr(ctxn) {
7022 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7026 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7031 void perf_event_mmap(struct vm_area_struct *vma)
7033 struct perf_mmap_event mmap_event;
7035 if (!atomic_read(&nr_mmap_events))
7038 mmap_event = (struct perf_mmap_event){
7044 .type = PERF_RECORD_MMAP,
7045 .misc = PERF_RECORD_MISC_USER,
7050 .start = vma->vm_start,
7051 .len = vma->vm_end - vma->vm_start,
7052 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7054 /* .maj (attr_mmap2 only) */
7055 /* .min (attr_mmap2 only) */
7056 /* .ino (attr_mmap2 only) */
7057 /* .ino_generation (attr_mmap2 only) */
7058 /* .prot (attr_mmap2 only) */
7059 /* .flags (attr_mmap2 only) */
7062 perf_addr_filters_adjust(vma);
7063 perf_event_mmap_event(&mmap_event);
7066 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7067 unsigned long size, u64 flags)
7069 struct perf_output_handle handle;
7070 struct perf_sample_data sample;
7071 struct perf_aux_event {
7072 struct perf_event_header header;
7078 .type = PERF_RECORD_AUX,
7080 .size = sizeof(rec),
7088 perf_event_header__init_id(&rec.header, &sample, event);
7089 ret = perf_output_begin(&handle, event, rec.header.size);
7094 perf_output_put(&handle, rec);
7095 perf_event__output_id_sample(event, &handle, &sample);
7097 perf_output_end(&handle);
7101 * Lost/dropped samples logging
7103 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7105 struct perf_output_handle handle;
7106 struct perf_sample_data sample;
7110 struct perf_event_header header;
7112 } lost_samples_event = {
7114 .type = PERF_RECORD_LOST_SAMPLES,
7116 .size = sizeof(lost_samples_event),
7121 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7123 ret = perf_output_begin(&handle, event,
7124 lost_samples_event.header.size);
7128 perf_output_put(&handle, lost_samples_event);
7129 perf_event__output_id_sample(event, &handle, &sample);
7130 perf_output_end(&handle);
7134 * context_switch tracking
7137 struct perf_switch_event {
7138 struct task_struct *task;
7139 struct task_struct *next_prev;
7142 struct perf_event_header header;
7148 static int perf_event_switch_match(struct perf_event *event)
7150 return event->attr.context_switch;
7153 static void perf_event_switch_output(struct perf_event *event, void *data)
7155 struct perf_switch_event *se = data;
7156 struct perf_output_handle handle;
7157 struct perf_sample_data sample;
7160 if (!perf_event_switch_match(event))
7163 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7164 if (event->ctx->task) {
7165 se->event_id.header.type = PERF_RECORD_SWITCH;
7166 se->event_id.header.size = sizeof(se->event_id.header);
7168 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7169 se->event_id.header.size = sizeof(se->event_id);
7170 se->event_id.next_prev_pid =
7171 perf_event_pid(event, se->next_prev);
7172 se->event_id.next_prev_tid =
7173 perf_event_tid(event, se->next_prev);
7176 perf_event_header__init_id(&se->event_id.header, &sample, event);
7178 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7182 if (event->ctx->task)
7183 perf_output_put(&handle, se->event_id.header);
7185 perf_output_put(&handle, se->event_id);
7187 perf_event__output_id_sample(event, &handle, &sample);
7189 perf_output_end(&handle);
7192 static void perf_event_switch(struct task_struct *task,
7193 struct task_struct *next_prev, bool sched_in)
7195 struct perf_switch_event switch_event;
7197 /* N.B. caller checks nr_switch_events != 0 */
7199 switch_event = (struct perf_switch_event){
7201 .next_prev = next_prev,
7205 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7208 /* .next_prev_pid */
7209 /* .next_prev_tid */
7213 perf_iterate_sb(perf_event_switch_output,
7219 * IRQ throttle logging
7222 static void perf_log_throttle(struct perf_event *event, int enable)
7224 struct perf_output_handle handle;
7225 struct perf_sample_data sample;
7229 struct perf_event_header header;
7233 } throttle_event = {
7235 .type = PERF_RECORD_THROTTLE,
7237 .size = sizeof(throttle_event),
7239 .time = perf_event_clock(event),
7240 .id = primary_event_id(event),
7241 .stream_id = event->id,
7245 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7247 perf_event_header__init_id(&throttle_event.header, &sample, event);
7249 ret = perf_output_begin(&handle, event,
7250 throttle_event.header.size);
7254 perf_output_put(&handle, throttle_event);
7255 perf_event__output_id_sample(event, &handle, &sample);
7256 perf_output_end(&handle);
7259 static void perf_log_itrace_start(struct perf_event *event)
7261 struct perf_output_handle handle;
7262 struct perf_sample_data sample;
7263 struct perf_aux_event {
7264 struct perf_event_header header;
7271 event = event->parent;
7273 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7274 event->hw.itrace_started)
7277 rec.header.type = PERF_RECORD_ITRACE_START;
7278 rec.header.misc = 0;
7279 rec.header.size = sizeof(rec);
7280 rec.pid = perf_event_pid(event, current);
7281 rec.tid = perf_event_tid(event, current);
7283 perf_event_header__init_id(&rec.header, &sample, event);
7284 ret = perf_output_begin(&handle, event, rec.header.size);
7289 perf_output_put(&handle, rec);
7290 perf_event__output_id_sample(event, &handle, &sample);
7292 perf_output_end(&handle);
7296 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7298 struct hw_perf_event *hwc = &event->hw;
7302 seq = __this_cpu_read(perf_throttled_seq);
7303 if (seq != hwc->interrupts_seq) {
7304 hwc->interrupts_seq = seq;
7305 hwc->interrupts = 1;
7308 if (unlikely(throttle
7309 && hwc->interrupts >= max_samples_per_tick)) {
7310 __this_cpu_inc(perf_throttled_count);
7311 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7312 hwc->interrupts = MAX_INTERRUPTS;
7313 perf_log_throttle(event, 0);
7318 if (event->attr.freq) {
7319 u64 now = perf_clock();
7320 s64 delta = now - hwc->freq_time_stamp;
7322 hwc->freq_time_stamp = now;
7324 if (delta > 0 && delta < 2*TICK_NSEC)
7325 perf_adjust_period(event, delta, hwc->last_period, true);
7331 int perf_event_account_interrupt(struct perf_event *event)
7333 return __perf_event_account_interrupt(event, 1);
7337 * Generic event overflow handling, sampling.
7340 static int __perf_event_overflow(struct perf_event *event,
7341 int throttle, struct perf_sample_data *data,
7342 struct pt_regs *regs)
7344 int events = atomic_read(&event->event_limit);
7348 * Non-sampling counters might still use the PMI to fold short
7349 * hardware counters, ignore those.
7351 if (unlikely(!is_sampling_event(event)))
7354 ret = __perf_event_account_interrupt(event, throttle);
7357 * XXX event_limit might not quite work as expected on inherited
7361 event->pending_kill = POLL_IN;
7362 if (events && atomic_dec_and_test(&event->event_limit)) {
7364 event->pending_kill = POLL_HUP;
7366 perf_event_disable_inatomic(event);
7369 READ_ONCE(event->overflow_handler)(event, data, regs);
7371 if (*perf_event_fasync(event) && event->pending_kill) {
7372 event->pending_wakeup = 1;
7373 irq_work_queue(&event->pending);
7379 int perf_event_overflow(struct perf_event *event,
7380 struct perf_sample_data *data,
7381 struct pt_regs *regs)
7383 return __perf_event_overflow(event, 1, data, regs);
7387 * Generic software event infrastructure
7390 struct swevent_htable {
7391 struct swevent_hlist *swevent_hlist;
7392 struct mutex hlist_mutex;
7395 /* Recursion avoidance in each contexts */
7396 int recursion[PERF_NR_CONTEXTS];
7399 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7402 * We directly increment event->count and keep a second value in
7403 * event->hw.period_left to count intervals. This period event
7404 * is kept in the range [-sample_period, 0] so that we can use the
7408 u64 perf_swevent_set_period(struct perf_event *event)
7410 struct hw_perf_event *hwc = &event->hw;
7411 u64 period = hwc->last_period;
7415 hwc->last_period = hwc->sample_period;
7418 old = val = local64_read(&hwc->period_left);
7422 nr = div64_u64(period + val, period);
7423 offset = nr * period;
7425 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7431 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7432 struct perf_sample_data *data,
7433 struct pt_regs *regs)
7435 struct hw_perf_event *hwc = &event->hw;
7439 overflow = perf_swevent_set_period(event);
7441 if (hwc->interrupts == MAX_INTERRUPTS)
7444 for (; overflow; overflow--) {
7445 if (__perf_event_overflow(event, throttle,
7448 * We inhibit the overflow from happening when
7449 * hwc->interrupts == MAX_INTERRUPTS.
7457 static void perf_swevent_event(struct perf_event *event, u64 nr,
7458 struct perf_sample_data *data,
7459 struct pt_regs *regs)
7461 struct hw_perf_event *hwc = &event->hw;
7463 local64_add(nr, &event->count);
7468 if (!is_sampling_event(event))
7471 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7473 return perf_swevent_overflow(event, 1, data, regs);
7475 data->period = event->hw.last_period;
7477 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7478 return perf_swevent_overflow(event, 1, data, regs);
7480 if (local64_add_negative(nr, &hwc->period_left))
7483 perf_swevent_overflow(event, 0, data, regs);
7486 static int perf_exclude_event(struct perf_event *event,
7487 struct pt_regs *regs)
7489 if (event->hw.state & PERF_HES_STOPPED)
7493 if (event->attr.exclude_user && user_mode(regs))
7496 if (event->attr.exclude_kernel && !user_mode(regs))
7503 static int perf_swevent_match(struct perf_event *event,
7504 enum perf_type_id type,
7506 struct perf_sample_data *data,
7507 struct pt_regs *regs)
7509 if (event->attr.type != type)
7512 if (event->attr.config != event_id)
7515 if (perf_exclude_event(event, regs))
7521 static inline u64 swevent_hash(u64 type, u32 event_id)
7523 u64 val = event_id | (type << 32);
7525 return hash_64(val, SWEVENT_HLIST_BITS);
7528 static inline struct hlist_head *
7529 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7531 u64 hash = swevent_hash(type, event_id);
7533 return &hlist->heads[hash];
7536 /* For the read side: events when they trigger */
7537 static inline struct hlist_head *
7538 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7540 struct swevent_hlist *hlist;
7542 hlist = rcu_dereference(swhash->swevent_hlist);
7546 return __find_swevent_head(hlist, type, event_id);
7549 /* For the event head insertion and removal in the hlist */
7550 static inline struct hlist_head *
7551 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7553 struct swevent_hlist *hlist;
7554 u32 event_id = event->attr.config;
7555 u64 type = event->attr.type;
7558 * Event scheduling is always serialized against hlist allocation
7559 * and release. Which makes the protected version suitable here.
7560 * The context lock guarantees that.
7562 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7563 lockdep_is_held(&event->ctx->lock));
7567 return __find_swevent_head(hlist, type, event_id);
7570 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7572 struct perf_sample_data *data,
7573 struct pt_regs *regs)
7575 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7576 struct perf_event *event;
7577 struct hlist_head *head;
7580 head = find_swevent_head_rcu(swhash, type, event_id);
7584 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7585 if (perf_swevent_match(event, type, event_id, data, regs))
7586 perf_swevent_event(event, nr, data, regs);
7592 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7594 int perf_swevent_get_recursion_context(void)
7596 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7598 return get_recursion_context(swhash->recursion);
7600 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7602 void perf_swevent_put_recursion_context(int rctx)
7604 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7606 put_recursion_context(swhash->recursion, rctx);
7609 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7611 struct perf_sample_data data;
7613 if (WARN_ON_ONCE(!regs))
7616 perf_sample_data_init(&data, addr, 0);
7617 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7620 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7624 preempt_disable_notrace();
7625 rctx = perf_swevent_get_recursion_context();
7626 if (unlikely(rctx < 0))
7629 ___perf_sw_event(event_id, nr, regs, addr);
7631 perf_swevent_put_recursion_context(rctx);
7633 preempt_enable_notrace();
7636 static void perf_swevent_read(struct perf_event *event)
7640 static int perf_swevent_add(struct perf_event *event, int flags)
7642 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7643 struct hw_perf_event *hwc = &event->hw;
7644 struct hlist_head *head;
7646 if (is_sampling_event(event)) {
7647 hwc->last_period = hwc->sample_period;
7648 perf_swevent_set_period(event);
7651 hwc->state = !(flags & PERF_EF_START);
7653 head = find_swevent_head(swhash, event);
7654 if (WARN_ON_ONCE(!head))
7657 hlist_add_head_rcu(&event->hlist_entry, head);
7658 perf_event_update_userpage(event);
7663 static void perf_swevent_del(struct perf_event *event, int flags)
7665 hlist_del_rcu(&event->hlist_entry);
7668 static void perf_swevent_start(struct perf_event *event, int flags)
7670 event->hw.state = 0;
7673 static void perf_swevent_stop(struct perf_event *event, int flags)
7675 event->hw.state = PERF_HES_STOPPED;
7678 /* Deref the hlist from the update side */
7679 static inline struct swevent_hlist *
7680 swevent_hlist_deref(struct swevent_htable *swhash)
7682 return rcu_dereference_protected(swhash->swevent_hlist,
7683 lockdep_is_held(&swhash->hlist_mutex));
7686 static void swevent_hlist_release(struct swevent_htable *swhash)
7688 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7693 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7694 kfree_rcu(hlist, rcu_head);
7697 static void swevent_hlist_put_cpu(int cpu)
7699 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7701 mutex_lock(&swhash->hlist_mutex);
7703 if (!--swhash->hlist_refcount)
7704 swevent_hlist_release(swhash);
7706 mutex_unlock(&swhash->hlist_mutex);
7709 static void swevent_hlist_put(void)
7713 for_each_possible_cpu(cpu)
7714 swevent_hlist_put_cpu(cpu);
7717 static int swevent_hlist_get_cpu(int cpu)
7719 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7722 mutex_lock(&swhash->hlist_mutex);
7723 if (!swevent_hlist_deref(swhash) &&
7724 cpumask_test_cpu(cpu, perf_online_mask)) {
7725 struct swevent_hlist *hlist;
7727 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7732 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7734 swhash->hlist_refcount++;
7736 mutex_unlock(&swhash->hlist_mutex);
7741 static int swevent_hlist_get(void)
7743 int err, cpu, failed_cpu;
7745 mutex_lock(&pmus_lock);
7746 for_each_possible_cpu(cpu) {
7747 err = swevent_hlist_get_cpu(cpu);
7753 mutex_unlock(&pmus_lock);
7756 for_each_possible_cpu(cpu) {
7757 if (cpu == failed_cpu)
7759 swevent_hlist_put_cpu(cpu);
7761 mutex_unlock(&pmus_lock);
7765 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7767 static void sw_perf_event_destroy(struct perf_event *event)
7769 u64 event_id = event->attr.config;
7771 WARN_ON(event->parent);
7773 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7774 swevent_hlist_put();
7777 static int perf_swevent_init(struct perf_event *event)
7779 u64 event_id = event->attr.config;
7781 if (event->attr.type != PERF_TYPE_SOFTWARE)
7785 * no branch sampling for software events
7787 if (has_branch_stack(event))
7791 case PERF_COUNT_SW_CPU_CLOCK:
7792 case PERF_COUNT_SW_TASK_CLOCK:
7799 if (event_id >= PERF_COUNT_SW_MAX)
7802 if (!event->parent) {
7805 err = swevent_hlist_get();
7809 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7810 event->destroy = sw_perf_event_destroy;
7816 static struct pmu perf_swevent = {
7817 .task_ctx_nr = perf_sw_context,
7819 .capabilities = PERF_PMU_CAP_NO_NMI,
7821 .event_init = perf_swevent_init,
7822 .add = perf_swevent_add,
7823 .del = perf_swevent_del,
7824 .start = perf_swevent_start,
7825 .stop = perf_swevent_stop,
7826 .read = perf_swevent_read,
7829 #ifdef CONFIG_EVENT_TRACING
7831 static int perf_tp_filter_match(struct perf_event *event,
7832 struct perf_sample_data *data)
7834 void *record = data->raw->frag.data;
7836 /* only top level events have filters set */
7838 event = event->parent;
7840 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7845 static int perf_tp_event_match(struct perf_event *event,
7846 struct perf_sample_data *data,
7847 struct pt_regs *regs)
7849 if (event->hw.state & PERF_HES_STOPPED)
7852 * All tracepoints are from kernel-space.
7854 if (event->attr.exclude_kernel)
7857 if (!perf_tp_filter_match(event, data))
7863 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7864 struct trace_event_call *call, u64 count,
7865 struct pt_regs *regs, struct hlist_head *head,
7866 struct task_struct *task)
7868 struct bpf_prog *prog = call->prog;
7871 *(struct pt_regs **)raw_data = regs;
7872 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7873 perf_swevent_put_recursion_context(rctx);
7877 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7880 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7882 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7883 struct pt_regs *regs, struct hlist_head *head, int rctx,
7884 struct task_struct *task)
7886 struct perf_sample_data data;
7887 struct perf_event *event;
7889 struct perf_raw_record raw = {
7896 perf_sample_data_init(&data, 0, 0);
7899 perf_trace_buf_update(record, event_type);
7901 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7902 if (perf_tp_event_match(event, &data, regs))
7903 perf_swevent_event(event, count, &data, regs);
7907 * If we got specified a target task, also iterate its context and
7908 * deliver this event there too.
7910 if (task && task != current) {
7911 struct perf_event_context *ctx;
7912 struct trace_entry *entry = record;
7915 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7919 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7920 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7922 if (event->attr.config != entry->type)
7924 if (perf_tp_event_match(event, &data, regs))
7925 perf_swevent_event(event, count, &data, regs);
7931 perf_swevent_put_recursion_context(rctx);
7933 EXPORT_SYMBOL_GPL(perf_tp_event);
7935 static void tp_perf_event_destroy(struct perf_event *event)
7937 perf_trace_destroy(event);
7940 static int perf_tp_event_init(struct perf_event *event)
7944 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7948 * no branch sampling for tracepoint events
7950 if (has_branch_stack(event))
7953 err = perf_trace_init(event);
7957 event->destroy = tp_perf_event_destroy;
7962 static struct pmu perf_tracepoint = {
7963 .task_ctx_nr = perf_sw_context,
7965 .event_init = perf_tp_event_init,
7966 .add = perf_trace_add,
7967 .del = perf_trace_del,
7968 .start = perf_swevent_start,
7969 .stop = perf_swevent_stop,
7970 .read = perf_swevent_read,
7973 static inline void perf_tp_register(void)
7975 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7978 static void perf_event_free_filter(struct perf_event *event)
7980 ftrace_profile_free_filter(event);
7983 #ifdef CONFIG_BPF_SYSCALL
7984 static void bpf_overflow_handler(struct perf_event *event,
7985 struct perf_sample_data *data,
7986 struct pt_regs *regs)
7988 struct bpf_perf_event_data_kern ctx = {
7995 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7998 ret = BPF_PROG_RUN(event->prog, &ctx);
8001 __this_cpu_dec(bpf_prog_active);
8006 event->orig_overflow_handler(event, data, regs);
8009 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8011 struct bpf_prog *prog;
8013 if (event->overflow_handler_context)
8014 /* hw breakpoint or kernel counter */
8020 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8022 return PTR_ERR(prog);
8025 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8026 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8030 static void perf_event_free_bpf_handler(struct perf_event *event)
8032 struct bpf_prog *prog = event->prog;
8037 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8042 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8046 static void perf_event_free_bpf_handler(struct perf_event *event)
8051 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8053 bool is_kprobe, is_tracepoint;
8054 struct bpf_prog *prog;
8056 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8057 return perf_event_set_bpf_handler(event, prog_fd);
8059 if (event->tp_event->prog)
8062 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8063 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8064 if (!is_kprobe && !is_tracepoint)
8065 /* bpf programs can only be attached to u/kprobe or tracepoint */
8068 prog = bpf_prog_get(prog_fd);
8070 return PTR_ERR(prog);
8072 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8073 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8074 /* valid fd, but invalid bpf program type */
8079 if (is_tracepoint) {
8080 int off = trace_event_get_offsets(event->tp_event);
8082 if (prog->aux->max_ctx_offset > off) {
8087 event->tp_event->prog = prog;
8092 static void perf_event_free_bpf_prog(struct perf_event *event)
8094 struct bpf_prog *prog;
8096 perf_event_free_bpf_handler(event);
8098 if (!event->tp_event)
8101 prog = event->tp_event->prog;
8103 event->tp_event->prog = NULL;
8110 static inline void perf_tp_register(void)
8114 static void perf_event_free_filter(struct perf_event *event)
8118 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8123 static void perf_event_free_bpf_prog(struct perf_event *event)
8126 #endif /* CONFIG_EVENT_TRACING */
8128 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8129 void perf_bp_event(struct perf_event *bp, void *data)
8131 struct perf_sample_data sample;
8132 struct pt_regs *regs = data;
8134 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8136 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8137 perf_swevent_event(bp, 1, &sample, regs);
8142 * Allocate a new address filter
8144 static struct perf_addr_filter *
8145 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8147 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8148 struct perf_addr_filter *filter;
8150 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8154 INIT_LIST_HEAD(&filter->entry);
8155 list_add_tail(&filter->entry, filters);
8160 static void free_filters_list(struct list_head *filters)
8162 struct perf_addr_filter *filter, *iter;
8164 list_for_each_entry_safe(filter, iter, filters, entry) {
8166 iput(filter->inode);
8167 list_del(&filter->entry);
8173 * Free existing address filters and optionally install new ones
8175 static void perf_addr_filters_splice(struct perf_event *event,
8176 struct list_head *head)
8178 unsigned long flags;
8181 if (!has_addr_filter(event))
8184 /* don't bother with children, they don't have their own filters */
8188 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8190 list_splice_init(&event->addr_filters.list, &list);
8192 list_splice(head, &event->addr_filters.list);
8194 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8196 free_filters_list(&list);
8200 * Scan through mm's vmas and see if one of them matches the
8201 * @filter; if so, adjust filter's address range.
8202 * Called with mm::mmap_sem down for reading.
8204 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8205 struct mm_struct *mm)
8207 struct vm_area_struct *vma;
8209 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8210 struct file *file = vma->vm_file;
8211 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8212 unsigned long vma_size = vma->vm_end - vma->vm_start;
8217 if (!perf_addr_filter_match(filter, file, off, vma_size))
8220 return vma->vm_start;
8227 * Update event's address range filters based on the
8228 * task's existing mappings, if any.
8230 static void perf_event_addr_filters_apply(struct perf_event *event)
8232 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8233 struct task_struct *task = READ_ONCE(event->ctx->task);
8234 struct perf_addr_filter *filter;
8235 struct mm_struct *mm = NULL;
8236 unsigned int count = 0;
8237 unsigned long flags;
8240 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8241 * will stop on the parent's child_mutex that our caller is also holding
8243 if (task == TASK_TOMBSTONE)
8246 if (!ifh->nr_file_filters)
8249 mm = get_task_mm(event->ctx->task);
8253 down_read(&mm->mmap_sem);
8255 raw_spin_lock_irqsave(&ifh->lock, flags);
8256 list_for_each_entry(filter, &ifh->list, entry) {
8257 event->addr_filters_offs[count] = 0;
8260 * Adjust base offset if the filter is associated to a binary
8261 * that needs to be mapped:
8264 event->addr_filters_offs[count] =
8265 perf_addr_filter_apply(filter, mm);
8270 event->addr_filters_gen++;
8271 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8273 up_read(&mm->mmap_sem);
8278 perf_event_stop(event, 1);
8282 * Address range filtering: limiting the data to certain
8283 * instruction address ranges. Filters are ioctl()ed to us from
8284 * userspace as ascii strings.
8286 * Filter string format:
8289 * where ACTION is one of the
8290 * * "filter": limit the trace to this region
8291 * * "start": start tracing from this address
8292 * * "stop": stop tracing at this address/region;
8294 * * for kernel addresses: <start address>[/<size>]
8295 * * for object files: <start address>[/<size>]@</path/to/object/file>
8297 * if <size> is not specified, the range is treated as a single address.
8311 IF_STATE_ACTION = 0,
8316 static const match_table_t if_tokens = {
8317 { IF_ACT_FILTER, "filter" },
8318 { IF_ACT_START, "start" },
8319 { IF_ACT_STOP, "stop" },
8320 { IF_SRC_FILE, "%u/%u@%s" },
8321 { IF_SRC_KERNEL, "%u/%u" },
8322 { IF_SRC_FILEADDR, "%u@%s" },
8323 { IF_SRC_KERNELADDR, "%u" },
8324 { IF_ACT_NONE, NULL },
8328 * Address filter string parser
8331 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8332 struct list_head *filters)
8334 struct perf_addr_filter *filter = NULL;
8335 char *start, *orig, *filename = NULL;
8337 substring_t args[MAX_OPT_ARGS];
8338 int state = IF_STATE_ACTION, token;
8339 unsigned int kernel = 0;
8342 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8346 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8352 /* filter definition begins */
8353 if (state == IF_STATE_ACTION) {
8354 filter = perf_addr_filter_new(event, filters);
8359 token = match_token(start, if_tokens, args);
8366 if (state != IF_STATE_ACTION)
8369 state = IF_STATE_SOURCE;
8372 case IF_SRC_KERNELADDR:
8376 case IF_SRC_FILEADDR:
8378 if (state != IF_STATE_SOURCE)
8381 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8385 ret = kstrtoul(args[0].from, 0, &filter->offset);
8389 if (filter->range) {
8391 ret = kstrtoul(args[1].from, 0, &filter->size);
8396 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8397 int fpos = filter->range ? 2 : 1;
8399 filename = match_strdup(&args[fpos]);
8406 state = IF_STATE_END;
8414 * Filter definition is fully parsed, validate and install it.
8415 * Make sure that it doesn't contradict itself or the event's
8418 if (state == IF_STATE_END) {
8420 if (kernel && event->attr.exclude_kernel)
8428 * For now, we only support file-based filters
8429 * in per-task events; doing so for CPU-wide
8430 * events requires additional context switching
8431 * trickery, since same object code will be
8432 * mapped at different virtual addresses in
8433 * different processes.
8436 if (!event->ctx->task)
8437 goto fail_free_name;
8439 /* look up the path and grab its inode */
8440 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8442 goto fail_free_name;
8444 filter->inode = igrab(d_inode(path.dentry));
8450 if (!filter->inode ||
8451 !S_ISREG(filter->inode->i_mode))
8452 /* free_filters_list() will iput() */
8455 event->addr_filters.nr_file_filters++;
8458 /* ready to consume more filters */
8459 state = IF_STATE_ACTION;
8464 if (state != IF_STATE_ACTION)
8474 free_filters_list(filters);
8481 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8487 * Since this is called in perf_ioctl() path, we're already holding
8490 lockdep_assert_held(&event->ctx->mutex);
8492 if (WARN_ON_ONCE(event->parent))
8495 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8497 goto fail_clear_files;
8499 ret = event->pmu->addr_filters_validate(&filters);
8501 goto fail_free_filters;
8503 /* remove existing filters, if any */
8504 perf_addr_filters_splice(event, &filters);
8506 /* install new filters */
8507 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8512 free_filters_list(&filters);
8515 event->addr_filters.nr_file_filters = 0;
8520 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8525 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8526 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8527 !has_addr_filter(event))
8530 filter_str = strndup_user(arg, PAGE_SIZE);
8531 if (IS_ERR(filter_str))
8532 return PTR_ERR(filter_str);
8534 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8535 event->attr.type == PERF_TYPE_TRACEPOINT)
8536 ret = ftrace_profile_set_filter(event, event->attr.config,
8538 else if (has_addr_filter(event))
8539 ret = perf_event_set_addr_filter(event, filter_str);
8546 * hrtimer based swevent callback
8549 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8551 enum hrtimer_restart ret = HRTIMER_RESTART;
8552 struct perf_sample_data data;
8553 struct pt_regs *regs;
8554 struct perf_event *event;
8557 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8559 if (event->state != PERF_EVENT_STATE_ACTIVE)
8560 return HRTIMER_NORESTART;
8562 event->pmu->read(event);
8564 perf_sample_data_init(&data, 0, event->hw.last_period);
8565 regs = get_irq_regs();
8567 if (regs && !perf_exclude_event(event, regs)) {
8568 if (!(event->attr.exclude_idle && is_idle_task(current)))
8569 if (__perf_event_overflow(event, 1, &data, regs))
8570 ret = HRTIMER_NORESTART;
8573 period = max_t(u64, 10000, event->hw.sample_period);
8574 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8579 static void perf_swevent_start_hrtimer(struct perf_event *event)
8581 struct hw_perf_event *hwc = &event->hw;
8584 if (!is_sampling_event(event))
8587 period = local64_read(&hwc->period_left);
8592 local64_set(&hwc->period_left, 0);
8594 period = max_t(u64, 10000, hwc->sample_period);
8596 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8597 HRTIMER_MODE_REL_PINNED);
8600 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8602 struct hw_perf_event *hwc = &event->hw;
8604 if (is_sampling_event(event)) {
8605 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8606 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8608 hrtimer_cancel(&hwc->hrtimer);
8612 static void perf_swevent_init_hrtimer(struct perf_event *event)
8614 struct hw_perf_event *hwc = &event->hw;
8616 if (!is_sampling_event(event))
8619 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8620 hwc->hrtimer.function = perf_swevent_hrtimer;
8623 * Since hrtimers have a fixed rate, we can do a static freq->period
8624 * mapping and avoid the whole period adjust feedback stuff.
8626 if (event->attr.freq) {
8627 long freq = event->attr.sample_freq;
8629 event->attr.sample_period = NSEC_PER_SEC / freq;
8630 hwc->sample_period = event->attr.sample_period;
8631 local64_set(&hwc->period_left, hwc->sample_period);
8632 hwc->last_period = hwc->sample_period;
8633 event->attr.freq = 0;
8638 * Software event: cpu wall time clock
8641 static void cpu_clock_event_update(struct perf_event *event)
8646 now = local_clock();
8647 prev = local64_xchg(&event->hw.prev_count, now);
8648 local64_add(now - prev, &event->count);
8651 static void cpu_clock_event_start(struct perf_event *event, int flags)
8653 local64_set(&event->hw.prev_count, local_clock());
8654 perf_swevent_start_hrtimer(event);
8657 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8659 perf_swevent_cancel_hrtimer(event);
8660 cpu_clock_event_update(event);
8663 static int cpu_clock_event_add(struct perf_event *event, int flags)
8665 if (flags & PERF_EF_START)
8666 cpu_clock_event_start(event, flags);
8667 perf_event_update_userpage(event);
8672 static void cpu_clock_event_del(struct perf_event *event, int flags)
8674 cpu_clock_event_stop(event, flags);
8677 static void cpu_clock_event_read(struct perf_event *event)
8679 cpu_clock_event_update(event);
8682 static int cpu_clock_event_init(struct perf_event *event)
8684 if (event->attr.type != PERF_TYPE_SOFTWARE)
8687 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8691 * no branch sampling for software events
8693 if (has_branch_stack(event))
8696 perf_swevent_init_hrtimer(event);
8701 static struct pmu perf_cpu_clock = {
8702 .task_ctx_nr = perf_sw_context,
8704 .capabilities = PERF_PMU_CAP_NO_NMI,
8706 .event_init = cpu_clock_event_init,
8707 .add = cpu_clock_event_add,
8708 .del = cpu_clock_event_del,
8709 .start = cpu_clock_event_start,
8710 .stop = cpu_clock_event_stop,
8711 .read = cpu_clock_event_read,
8715 * Software event: task time clock
8718 static void task_clock_event_update(struct perf_event *event, u64 now)
8723 prev = local64_xchg(&event->hw.prev_count, now);
8725 local64_add(delta, &event->count);
8728 static void task_clock_event_start(struct perf_event *event, int flags)
8730 local64_set(&event->hw.prev_count, event->ctx->time);
8731 perf_swevent_start_hrtimer(event);
8734 static void task_clock_event_stop(struct perf_event *event, int flags)
8736 perf_swevent_cancel_hrtimer(event);
8737 task_clock_event_update(event, event->ctx->time);
8740 static int task_clock_event_add(struct perf_event *event, int flags)
8742 if (flags & PERF_EF_START)
8743 task_clock_event_start(event, flags);
8744 perf_event_update_userpage(event);
8749 static void task_clock_event_del(struct perf_event *event, int flags)
8751 task_clock_event_stop(event, PERF_EF_UPDATE);
8754 static void task_clock_event_read(struct perf_event *event)
8756 u64 now = perf_clock();
8757 u64 delta = now - event->ctx->timestamp;
8758 u64 time = event->ctx->time + delta;
8760 task_clock_event_update(event, time);
8763 static int task_clock_event_init(struct perf_event *event)
8765 if (event->attr.type != PERF_TYPE_SOFTWARE)
8768 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8772 * no branch sampling for software events
8774 if (has_branch_stack(event))
8777 perf_swevent_init_hrtimer(event);
8782 static struct pmu perf_task_clock = {
8783 .task_ctx_nr = perf_sw_context,
8785 .capabilities = PERF_PMU_CAP_NO_NMI,
8787 .event_init = task_clock_event_init,
8788 .add = task_clock_event_add,
8789 .del = task_clock_event_del,
8790 .start = task_clock_event_start,
8791 .stop = task_clock_event_stop,
8792 .read = task_clock_event_read,
8795 static void perf_pmu_nop_void(struct pmu *pmu)
8799 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8803 static int perf_pmu_nop_int(struct pmu *pmu)
8808 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8810 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8812 __this_cpu_write(nop_txn_flags, flags);
8814 if (flags & ~PERF_PMU_TXN_ADD)
8817 perf_pmu_disable(pmu);
8820 static int perf_pmu_commit_txn(struct pmu *pmu)
8822 unsigned int flags = __this_cpu_read(nop_txn_flags);
8824 __this_cpu_write(nop_txn_flags, 0);
8826 if (flags & ~PERF_PMU_TXN_ADD)
8829 perf_pmu_enable(pmu);
8833 static void perf_pmu_cancel_txn(struct pmu *pmu)
8835 unsigned int flags = __this_cpu_read(nop_txn_flags);
8837 __this_cpu_write(nop_txn_flags, 0);
8839 if (flags & ~PERF_PMU_TXN_ADD)
8842 perf_pmu_enable(pmu);
8845 static int perf_event_idx_default(struct perf_event *event)
8851 * Ensures all contexts with the same task_ctx_nr have the same
8852 * pmu_cpu_context too.
8854 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8861 list_for_each_entry(pmu, &pmus, entry) {
8862 if (pmu->task_ctx_nr == ctxn)
8863 return pmu->pmu_cpu_context;
8869 static void free_pmu_context(struct pmu *pmu)
8871 mutex_lock(&pmus_lock);
8872 free_percpu(pmu->pmu_cpu_context);
8873 mutex_unlock(&pmus_lock);
8877 * Let userspace know that this PMU supports address range filtering:
8879 static ssize_t nr_addr_filters_show(struct device *dev,
8880 struct device_attribute *attr,
8883 struct pmu *pmu = dev_get_drvdata(dev);
8885 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8887 DEVICE_ATTR_RO(nr_addr_filters);
8889 static struct idr pmu_idr;
8892 type_show(struct device *dev, struct device_attribute *attr, char *page)
8894 struct pmu *pmu = dev_get_drvdata(dev);
8896 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8898 static DEVICE_ATTR_RO(type);
8901 perf_event_mux_interval_ms_show(struct device *dev,
8902 struct device_attribute *attr,
8905 struct pmu *pmu = dev_get_drvdata(dev);
8907 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8910 static DEFINE_MUTEX(mux_interval_mutex);
8913 perf_event_mux_interval_ms_store(struct device *dev,
8914 struct device_attribute *attr,
8915 const char *buf, size_t count)
8917 struct pmu *pmu = dev_get_drvdata(dev);
8918 int timer, cpu, ret;
8920 ret = kstrtoint(buf, 0, &timer);
8927 /* same value, noting to do */
8928 if (timer == pmu->hrtimer_interval_ms)
8931 mutex_lock(&mux_interval_mutex);
8932 pmu->hrtimer_interval_ms = timer;
8934 /* update all cpuctx for this PMU */
8936 for_each_online_cpu(cpu) {
8937 struct perf_cpu_context *cpuctx;
8938 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8939 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8941 cpu_function_call(cpu,
8942 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8945 mutex_unlock(&mux_interval_mutex);
8949 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8951 static struct attribute *pmu_dev_attrs[] = {
8952 &dev_attr_type.attr,
8953 &dev_attr_perf_event_mux_interval_ms.attr,
8956 ATTRIBUTE_GROUPS(pmu_dev);
8958 static int pmu_bus_running;
8959 static struct bus_type pmu_bus = {
8960 .name = "event_source",
8961 .dev_groups = pmu_dev_groups,
8964 static void pmu_dev_release(struct device *dev)
8969 static int pmu_dev_alloc(struct pmu *pmu)
8973 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8977 pmu->dev->groups = pmu->attr_groups;
8978 device_initialize(pmu->dev);
8979 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8983 dev_set_drvdata(pmu->dev, pmu);
8984 pmu->dev->bus = &pmu_bus;
8985 pmu->dev->release = pmu_dev_release;
8986 ret = device_add(pmu->dev);
8990 /* For PMUs with address filters, throw in an extra attribute: */
8991 if (pmu->nr_addr_filters)
8992 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9001 device_del(pmu->dev);
9004 put_device(pmu->dev);
9008 static struct lock_class_key cpuctx_mutex;
9009 static struct lock_class_key cpuctx_lock;
9011 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9015 mutex_lock(&pmus_lock);
9017 pmu->pmu_disable_count = alloc_percpu(int);
9018 if (!pmu->pmu_disable_count)
9027 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9035 if (pmu_bus_running) {
9036 ret = pmu_dev_alloc(pmu);
9042 if (pmu->task_ctx_nr == perf_hw_context) {
9043 static int hw_context_taken = 0;
9046 * Other than systems with heterogeneous CPUs, it never makes
9047 * sense for two PMUs to share perf_hw_context. PMUs which are
9048 * uncore must use perf_invalid_context.
9050 if (WARN_ON_ONCE(hw_context_taken &&
9051 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9052 pmu->task_ctx_nr = perf_invalid_context;
9054 hw_context_taken = 1;
9057 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9058 if (pmu->pmu_cpu_context)
9059 goto got_cpu_context;
9062 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9063 if (!pmu->pmu_cpu_context)
9066 for_each_possible_cpu(cpu) {
9067 struct perf_cpu_context *cpuctx;
9069 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9070 __perf_event_init_context(&cpuctx->ctx);
9071 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9072 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9073 cpuctx->ctx.pmu = pmu;
9074 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9076 __perf_mux_hrtimer_init(cpuctx, cpu);
9080 if (!pmu->start_txn) {
9081 if (pmu->pmu_enable) {
9083 * If we have pmu_enable/pmu_disable calls, install
9084 * transaction stubs that use that to try and batch
9085 * hardware accesses.
9087 pmu->start_txn = perf_pmu_start_txn;
9088 pmu->commit_txn = perf_pmu_commit_txn;
9089 pmu->cancel_txn = perf_pmu_cancel_txn;
9091 pmu->start_txn = perf_pmu_nop_txn;
9092 pmu->commit_txn = perf_pmu_nop_int;
9093 pmu->cancel_txn = perf_pmu_nop_void;
9097 if (!pmu->pmu_enable) {
9098 pmu->pmu_enable = perf_pmu_nop_void;
9099 pmu->pmu_disable = perf_pmu_nop_void;
9102 if (!pmu->event_idx)
9103 pmu->event_idx = perf_event_idx_default;
9105 list_add_rcu(&pmu->entry, &pmus);
9106 atomic_set(&pmu->exclusive_cnt, 0);
9109 mutex_unlock(&pmus_lock);
9114 device_del(pmu->dev);
9115 put_device(pmu->dev);
9118 if (pmu->type >= PERF_TYPE_MAX)
9119 idr_remove(&pmu_idr, pmu->type);
9122 free_percpu(pmu->pmu_disable_count);
9125 EXPORT_SYMBOL_GPL(perf_pmu_register);
9127 void perf_pmu_unregister(struct pmu *pmu)
9131 mutex_lock(&pmus_lock);
9132 remove_device = pmu_bus_running;
9133 list_del_rcu(&pmu->entry);
9134 mutex_unlock(&pmus_lock);
9137 * We dereference the pmu list under both SRCU and regular RCU, so
9138 * synchronize against both of those.
9140 synchronize_srcu(&pmus_srcu);
9143 free_percpu(pmu->pmu_disable_count);
9144 if (pmu->type >= PERF_TYPE_MAX)
9145 idr_remove(&pmu_idr, pmu->type);
9146 if (remove_device) {
9147 if (pmu->nr_addr_filters)
9148 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9149 device_del(pmu->dev);
9150 put_device(pmu->dev);
9152 free_pmu_context(pmu);
9154 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9156 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9158 struct perf_event_context *ctx = NULL;
9161 if (!try_module_get(pmu->module))
9164 if (event->group_leader != event) {
9166 * This ctx->mutex can nest when we're called through
9167 * inheritance. See the perf_event_ctx_lock_nested() comment.
9169 ctx = perf_event_ctx_lock_nested(event->group_leader,
9170 SINGLE_DEPTH_NESTING);
9175 ret = pmu->event_init(event);
9178 perf_event_ctx_unlock(event->group_leader, ctx);
9181 module_put(pmu->module);
9186 static struct pmu *perf_init_event(struct perf_event *event)
9192 idx = srcu_read_lock(&pmus_srcu);
9194 /* Try parent's PMU first: */
9195 if (event->parent && event->parent->pmu) {
9196 pmu = event->parent->pmu;
9197 ret = perf_try_init_event(pmu, event);
9203 pmu = idr_find(&pmu_idr, event->attr.type);
9206 ret = perf_try_init_event(pmu, event);
9212 list_for_each_entry_rcu(pmu, &pmus, entry) {
9213 ret = perf_try_init_event(pmu, event);
9217 if (ret != -ENOENT) {
9222 pmu = ERR_PTR(-ENOENT);
9224 srcu_read_unlock(&pmus_srcu, idx);
9229 static void attach_sb_event(struct perf_event *event)
9231 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9233 raw_spin_lock(&pel->lock);
9234 list_add_rcu(&event->sb_list, &pel->list);
9235 raw_spin_unlock(&pel->lock);
9239 * We keep a list of all !task (and therefore per-cpu) events
9240 * that need to receive side-band records.
9242 * This avoids having to scan all the various PMU per-cpu contexts
9245 static void account_pmu_sb_event(struct perf_event *event)
9247 if (is_sb_event(event))
9248 attach_sb_event(event);
9251 static void account_event_cpu(struct perf_event *event, int cpu)
9256 if (is_cgroup_event(event))
9257 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9260 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9261 static void account_freq_event_nohz(void)
9263 #ifdef CONFIG_NO_HZ_FULL
9264 /* Lock so we don't race with concurrent unaccount */
9265 spin_lock(&nr_freq_lock);
9266 if (atomic_inc_return(&nr_freq_events) == 1)
9267 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9268 spin_unlock(&nr_freq_lock);
9272 static void account_freq_event(void)
9274 if (tick_nohz_full_enabled())
9275 account_freq_event_nohz();
9277 atomic_inc(&nr_freq_events);
9281 static void account_event(struct perf_event *event)
9288 if (event->attach_state & PERF_ATTACH_TASK)
9290 if (event->attr.mmap || event->attr.mmap_data)
9291 atomic_inc(&nr_mmap_events);
9292 if (event->attr.comm)
9293 atomic_inc(&nr_comm_events);
9294 if (event->attr.namespaces)
9295 atomic_inc(&nr_namespaces_events);
9296 if (event->attr.task)
9297 atomic_inc(&nr_task_events);
9298 if (event->attr.freq)
9299 account_freq_event();
9300 if (event->attr.context_switch) {
9301 atomic_inc(&nr_switch_events);
9304 if (has_branch_stack(event))
9306 if (is_cgroup_event(event))
9310 if (atomic_inc_not_zero(&perf_sched_count))
9313 mutex_lock(&perf_sched_mutex);
9314 if (!atomic_read(&perf_sched_count)) {
9315 static_branch_enable(&perf_sched_events);
9317 * Guarantee that all CPUs observe they key change and
9318 * call the perf scheduling hooks before proceeding to
9319 * install events that need them.
9321 synchronize_sched();
9324 * Now that we have waited for the sync_sched(), allow further
9325 * increments to by-pass the mutex.
9327 atomic_inc(&perf_sched_count);
9328 mutex_unlock(&perf_sched_mutex);
9332 account_event_cpu(event, event->cpu);
9334 account_pmu_sb_event(event);
9338 * Allocate and initialize a event structure
9340 static struct perf_event *
9341 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9342 struct task_struct *task,
9343 struct perf_event *group_leader,
9344 struct perf_event *parent_event,
9345 perf_overflow_handler_t overflow_handler,
9346 void *context, int cgroup_fd)
9349 struct perf_event *event;
9350 struct hw_perf_event *hwc;
9353 if ((unsigned)cpu >= nr_cpu_ids) {
9354 if (!task || cpu != -1)
9355 return ERR_PTR(-EINVAL);
9358 event = kzalloc(sizeof(*event), GFP_KERNEL);
9360 return ERR_PTR(-ENOMEM);
9363 * Single events are their own group leaders, with an
9364 * empty sibling list:
9367 group_leader = event;
9369 mutex_init(&event->child_mutex);
9370 INIT_LIST_HEAD(&event->child_list);
9372 INIT_LIST_HEAD(&event->group_entry);
9373 INIT_LIST_HEAD(&event->event_entry);
9374 INIT_LIST_HEAD(&event->sibling_list);
9375 INIT_LIST_HEAD(&event->rb_entry);
9376 INIT_LIST_HEAD(&event->active_entry);
9377 INIT_LIST_HEAD(&event->addr_filters.list);
9378 INIT_HLIST_NODE(&event->hlist_entry);
9381 init_waitqueue_head(&event->waitq);
9382 init_irq_work(&event->pending, perf_pending_event);
9384 mutex_init(&event->mmap_mutex);
9385 raw_spin_lock_init(&event->addr_filters.lock);
9387 atomic_long_set(&event->refcount, 1);
9389 event->attr = *attr;
9390 event->group_leader = group_leader;
9394 event->parent = parent_event;
9396 event->ns = get_pid_ns(task_active_pid_ns(current));
9397 event->id = atomic64_inc_return(&perf_event_id);
9399 event->state = PERF_EVENT_STATE_INACTIVE;
9402 event->attach_state = PERF_ATTACH_TASK;
9404 * XXX pmu::event_init needs to know what task to account to
9405 * and we cannot use the ctx information because we need the
9406 * pmu before we get a ctx.
9408 event->hw.target = task;
9411 event->clock = &local_clock;
9413 event->clock = parent_event->clock;
9415 if (!overflow_handler && parent_event) {
9416 overflow_handler = parent_event->overflow_handler;
9417 context = parent_event->overflow_handler_context;
9418 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9419 if (overflow_handler == bpf_overflow_handler) {
9420 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9423 err = PTR_ERR(prog);
9427 event->orig_overflow_handler =
9428 parent_event->orig_overflow_handler;
9433 if (overflow_handler) {
9434 event->overflow_handler = overflow_handler;
9435 event->overflow_handler_context = context;
9436 } else if (is_write_backward(event)){
9437 event->overflow_handler = perf_event_output_backward;
9438 event->overflow_handler_context = NULL;
9440 event->overflow_handler = perf_event_output_forward;
9441 event->overflow_handler_context = NULL;
9444 perf_event__state_init(event);
9449 hwc->sample_period = attr->sample_period;
9450 if (attr->freq && attr->sample_freq)
9451 hwc->sample_period = 1;
9452 hwc->last_period = hwc->sample_period;
9454 local64_set(&hwc->period_left, hwc->sample_period);
9457 * We currently do not support PERF_SAMPLE_READ on inherited events.
9458 * See perf_output_read().
9460 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9463 if (!has_branch_stack(event))
9464 event->attr.branch_sample_type = 0;
9466 if (cgroup_fd != -1) {
9467 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9472 pmu = perf_init_event(event);
9478 err = exclusive_event_init(event);
9482 if (has_addr_filter(event)) {
9483 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9484 sizeof(unsigned long),
9486 if (!event->addr_filters_offs) {
9491 /* force hw sync on the address filters */
9492 event->addr_filters_gen = 1;
9495 if (!event->parent) {
9496 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9497 err = get_callchain_buffers(attr->sample_max_stack);
9499 goto err_addr_filters;
9503 /* symmetric to unaccount_event() in _free_event() */
9504 account_event(event);
9509 kfree(event->addr_filters_offs);
9512 exclusive_event_destroy(event);
9516 event->destroy(event);
9517 module_put(pmu->module);
9519 if (is_cgroup_event(event))
9520 perf_detach_cgroup(event);
9522 put_pid_ns(event->ns);
9525 return ERR_PTR(err);
9528 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9529 struct perf_event_attr *attr)
9534 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9538 * zero the full structure, so that a short copy will be nice.
9540 memset(attr, 0, sizeof(*attr));
9542 ret = get_user(size, &uattr->size);
9546 if (size > PAGE_SIZE) /* silly large */
9549 if (!size) /* abi compat */
9550 size = PERF_ATTR_SIZE_VER0;
9552 if (size < PERF_ATTR_SIZE_VER0)
9556 * If we're handed a bigger struct than we know of,
9557 * ensure all the unknown bits are 0 - i.e. new
9558 * user-space does not rely on any kernel feature
9559 * extensions we dont know about yet.
9561 if (size > sizeof(*attr)) {
9562 unsigned char __user *addr;
9563 unsigned char __user *end;
9566 addr = (void __user *)uattr + sizeof(*attr);
9567 end = (void __user *)uattr + size;
9569 for (; addr < end; addr++) {
9570 ret = get_user(val, addr);
9576 size = sizeof(*attr);
9579 ret = copy_from_user(attr, uattr, size);
9583 if (attr->__reserved_1)
9586 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9589 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9592 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9593 u64 mask = attr->branch_sample_type;
9595 /* only using defined bits */
9596 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9599 /* at least one branch bit must be set */
9600 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9603 /* propagate priv level, when not set for branch */
9604 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9606 /* exclude_kernel checked on syscall entry */
9607 if (!attr->exclude_kernel)
9608 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9610 if (!attr->exclude_user)
9611 mask |= PERF_SAMPLE_BRANCH_USER;
9613 if (!attr->exclude_hv)
9614 mask |= PERF_SAMPLE_BRANCH_HV;
9616 * adjust user setting (for HW filter setup)
9618 attr->branch_sample_type = mask;
9620 /* privileged levels capture (kernel, hv): check permissions */
9621 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9622 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9626 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9627 ret = perf_reg_validate(attr->sample_regs_user);
9632 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9633 if (!arch_perf_have_user_stack_dump())
9637 * We have __u32 type for the size, but so far
9638 * we can only use __u16 as maximum due to the
9639 * __u16 sample size limit.
9641 if (attr->sample_stack_user >= USHRT_MAX)
9643 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9647 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9648 ret = perf_reg_validate(attr->sample_regs_intr);
9653 put_user(sizeof(*attr), &uattr->size);
9659 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9661 struct ring_buffer *rb = NULL;
9667 /* don't allow circular references */
9668 if (event == output_event)
9672 * Don't allow cross-cpu buffers
9674 if (output_event->cpu != event->cpu)
9678 * If its not a per-cpu rb, it must be the same task.
9680 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9684 * Mixing clocks in the same buffer is trouble you don't need.
9686 if (output_event->clock != event->clock)
9690 * Either writing ring buffer from beginning or from end.
9691 * Mixing is not allowed.
9693 if (is_write_backward(output_event) != is_write_backward(event))
9697 * If both events generate aux data, they must be on the same PMU
9699 if (has_aux(event) && has_aux(output_event) &&
9700 event->pmu != output_event->pmu)
9704 mutex_lock(&event->mmap_mutex);
9705 /* Can't redirect output if we've got an active mmap() */
9706 if (atomic_read(&event->mmap_count))
9710 /* get the rb we want to redirect to */
9711 rb = ring_buffer_get(output_event);
9716 ring_buffer_attach(event, rb);
9720 mutex_unlock(&event->mmap_mutex);
9726 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9732 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9735 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9737 bool nmi_safe = false;
9740 case CLOCK_MONOTONIC:
9741 event->clock = &ktime_get_mono_fast_ns;
9745 case CLOCK_MONOTONIC_RAW:
9746 event->clock = &ktime_get_raw_fast_ns;
9750 case CLOCK_REALTIME:
9751 event->clock = &ktime_get_real_ns;
9754 case CLOCK_BOOTTIME:
9755 event->clock = &ktime_get_boot_ns;
9759 event->clock = &ktime_get_tai_ns;
9766 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9773 * Variation on perf_event_ctx_lock_nested(), except we take two context
9776 static struct perf_event_context *
9777 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9778 struct perf_event_context *ctx)
9780 struct perf_event_context *gctx;
9784 gctx = READ_ONCE(group_leader->ctx);
9785 if (!atomic_inc_not_zero(&gctx->refcount)) {
9791 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9793 if (group_leader->ctx != gctx) {
9794 mutex_unlock(&ctx->mutex);
9795 mutex_unlock(&gctx->mutex);
9804 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9806 * @attr_uptr: event_id type attributes for monitoring/sampling
9809 * @group_fd: group leader event fd
9811 SYSCALL_DEFINE5(perf_event_open,
9812 struct perf_event_attr __user *, attr_uptr,
9813 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9815 struct perf_event *group_leader = NULL, *output_event = NULL;
9816 struct perf_event *event, *sibling;
9817 struct perf_event_attr attr;
9818 struct perf_event_context *ctx, *uninitialized_var(gctx);
9819 struct file *event_file = NULL;
9820 struct fd group = {NULL, 0};
9821 struct task_struct *task = NULL;
9826 int f_flags = O_RDWR;
9829 /* for future expandability... */
9830 if (flags & ~PERF_FLAG_ALL)
9833 err = perf_copy_attr(attr_uptr, &attr);
9837 if (!attr.exclude_kernel) {
9838 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9842 if (attr.namespaces) {
9843 if (!capable(CAP_SYS_ADMIN))
9848 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9851 if (attr.sample_period & (1ULL << 63))
9855 if (!attr.sample_max_stack)
9856 attr.sample_max_stack = sysctl_perf_event_max_stack;
9859 * In cgroup mode, the pid argument is used to pass the fd
9860 * opened to the cgroup directory in cgroupfs. The cpu argument
9861 * designates the cpu on which to monitor threads from that
9864 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9867 if (flags & PERF_FLAG_FD_CLOEXEC)
9868 f_flags |= O_CLOEXEC;
9870 event_fd = get_unused_fd_flags(f_flags);
9874 if (group_fd != -1) {
9875 err = perf_fget_light(group_fd, &group);
9878 group_leader = group.file->private_data;
9879 if (flags & PERF_FLAG_FD_OUTPUT)
9880 output_event = group_leader;
9881 if (flags & PERF_FLAG_FD_NO_GROUP)
9882 group_leader = NULL;
9885 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9886 task = find_lively_task_by_vpid(pid);
9888 err = PTR_ERR(task);
9893 if (task && group_leader &&
9894 group_leader->attr.inherit != attr.inherit) {
9900 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9905 * Reuse ptrace permission checks for now.
9907 * We must hold cred_guard_mutex across this and any potential
9908 * perf_install_in_context() call for this new event to
9909 * serialize against exec() altering our credentials (and the
9910 * perf_event_exit_task() that could imply).
9913 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9917 if (flags & PERF_FLAG_PID_CGROUP)
9920 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9921 NULL, NULL, cgroup_fd);
9922 if (IS_ERR(event)) {
9923 err = PTR_ERR(event);
9927 if (is_sampling_event(event)) {
9928 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9935 * Special case software events and allow them to be part of
9936 * any hardware group.
9940 if (attr.use_clockid) {
9941 err = perf_event_set_clock(event, attr.clockid);
9946 if (pmu->task_ctx_nr == perf_sw_context)
9947 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9950 (is_software_event(event) != is_software_event(group_leader))) {
9951 if (is_software_event(event)) {
9953 * If event and group_leader are not both a software
9954 * event, and event is, then group leader is not.
9956 * Allow the addition of software events to !software
9957 * groups, this is safe because software events never
9960 pmu = group_leader->pmu;
9961 } else if (is_software_event(group_leader) &&
9962 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9964 * In case the group is a pure software group, and we
9965 * try to add a hardware event, move the whole group to
9966 * the hardware context.
9973 * Get the target context (task or percpu):
9975 ctx = find_get_context(pmu, task, event);
9981 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9987 * Look up the group leader (we will attach this event to it):
9993 * Do not allow a recursive hierarchy (this new sibling
9994 * becoming part of another group-sibling):
9996 if (group_leader->group_leader != group_leader)
9999 /* All events in a group should have the same clock */
10000 if (group_leader->clock != event->clock)
10004 * Do not allow to attach to a group in a different
10005 * task or CPU context:
10009 * Make sure we're both on the same task, or both
10012 if (group_leader->ctx->task != ctx->task)
10016 * Make sure we're both events for the same CPU;
10017 * grouping events for different CPUs is broken; since
10018 * you can never concurrently schedule them anyhow.
10020 if (group_leader->cpu != event->cpu)
10023 if (group_leader->ctx != ctx)
10028 * Only a group leader can be exclusive or pinned
10030 if (attr.exclusive || attr.pinned)
10034 if (output_event) {
10035 err = perf_event_set_output(event, output_event);
10040 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10042 if (IS_ERR(event_file)) {
10043 err = PTR_ERR(event_file);
10049 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10051 if (gctx->task == TASK_TOMBSTONE) {
10057 * Check if we raced against another sys_perf_event_open() call
10058 * moving the software group underneath us.
10060 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10062 * If someone moved the group out from under us, check
10063 * if this new event wound up on the same ctx, if so
10064 * its the regular !move_group case, otherwise fail.
10070 perf_event_ctx_unlock(group_leader, gctx);
10075 mutex_lock(&ctx->mutex);
10078 if (ctx->task == TASK_TOMBSTONE) {
10083 if (!perf_event_validate_size(event)) {
10090 * Check if the @cpu we're creating an event for is online.
10092 * We use the perf_cpu_context::ctx::mutex to serialize against
10093 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10095 struct perf_cpu_context *cpuctx =
10096 container_of(ctx, struct perf_cpu_context, ctx);
10098 if (!cpuctx->online) {
10106 * Must be under the same ctx::mutex as perf_install_in_context(),
10107 * because we need to serialize with concurrent event creation.
10109 if (!exclusive_event_installable(event, ctx)) {
10110 /* exclusive and group stuff are assumed mutually exclusive */
10111 WARN_ON_ONCE(move_group);
10117 WARN_ON_ONCE(ctx->parent_ctx);
10120 * This is the point on no return; we cannot fail hereafter. This is
10121 * where we start modifying current state.
10126 * See perf_event_ctx_lock() for comments on the details
10127 * of swizzling perf_event::ctx.
10129 perf_remove_from_context(group_leader, 0);
10132 list_for_each_entry(sibling, &group_leader->sibling_list,
10134 perf_remove_from_context(sibling, 0);
10139 * Wait for everybody to stop referencing the events through
10140 * the old lists, before installing it on new lists.
10145 * Install the group siblings before the group leader.
10147 * Because a group leader will try and install the entire group
10148 * (through the sibling list, which is still in-tact), we can
10149 * end up with siblings installed in the wrong context.
10151 * By installing siblings first we NO-OP because they're not
10152 * reachable through the group lists.
10154 list_for_each_entry(sibling, &group_leader->sibling_list,
10156 perf_event__state_init(sibling);
10157 perf_install_in_context(ctx, sibling, sibling->cpu);
10162 * Removing from the context ends up with disabled
10163 * event. What we want here is event in the initial
10164 * startup state, ready to be add into new context.
10166 perf_event__state_init(group_leader);
10167 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10172 * Precalculate sample_data sizes; do while holding ctx::mutex such
10173 * that we're serialized against further additions and before
10174 * perf_install_in_context() which is the point the event is active and
10175 * can use these values.
10177 perf_event__header_size(event);
10178 perf_event__id_header_size(event);
10180 event->owner = current;
10182 perf_install_in_context(ctx, event, event->cpu);
10183 perf_unpin_context(ctx);
10186 perf_event_ctx_unlock(group_leader, gctx);
10187 mutex_unlock(&ctx->mutex);
10190 mutex_unlock(&task->signal->cred_guard_mutex);
10191 put_task_struct(task);
10194 mutex_lock(¤t->perf_event_mutex);
10195 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10196 mutex_unlock(¤t->perf_event_mutex);
10199 * Drop the reference on the group_event after placing the
10200 * new event on the sibling_list. This ensures destruction
10201 * of the group leader will find the pointer to itself in
10202 * perf_group_detach().
10205 fd_install(event_fd, event_file);
10210 perf_event_ctx_unlock(group_leader, gctx);
10211 mutex_unlock(&ctx->mutex);
10215 perf_unpin_context(ctx);
10219 * If event_file is set, the fput() above will have called ->release()
10220 * and that will take care of freeing the event.
10226 mutex_unlock(&task->signal->cred_guard_mutex);
10229 put_task_struct(task);
10233 put_unused_fd(event_fd);
10238 * perf_event_create_kernel_counter
10240 * @attr: attributes of the counter to create
10241 * @cpu: cpu in which the counter is bound
10242 * @task: task to profile (NULL for percpu)
10244 struct perf_event *
10245 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10246 struct task_struct *task,
10247 perf_overflow_handler_t overflow_handler,
10250 struct perf_event_context *ctx;
10251 struct perf_event *event;
10255 * Get the target context (task or percpu):
10258 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10259 overflow_handler, context, -1);
10260 if (IS_ERR(event)) {
10261 err = PTR_ERR(event);
10265 /* Mark owner so we could distinguish it from user events. */
10266 event->owner = TASK_TOMBSTONE;
10268 ctx = find_get_context(event->pmu, task, event);
10270 err = PTR_ERR(ctx);
10274 WARN_ON_ONCE(ctx->parent_ctx);
10275 mutex_lock(&ctx->mutex);
10276 if (ctx->task == TASK_TOMBSTONE) {
10283 * Check if the @cpu we're creating an event for is online.
10285 * We use the perf_cpu_context::ctx::mutex to serialize against
10286 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10288 struct perf_cpu_context *cpuctx =
10289 container_of(ctx, struct perf_cpu_context, ctx);
10290 if (!cpuctx->online) {
10296 if (!exclusive_event_installable(event, ctx)) {
10301 perf_install_in_context(ctx, event, cpu);
10302 perf_unpin_context(ctx);
10303 mutex_unlock(&ctx->mutex);
10308 mutex_unlock(&ctx->mutex);
10309 perf_unpin_context(ctx);
10314 return ERR_PTR(err);
10316 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10318 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10320 struct perf_event_context *src_ctx;
10321 struct perf_event_context *dst_ctx;
10322 struct perf_event *event, *tmp;
10325 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10326 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10329 * See perf_event_ctx_lock() for comments on the details
10330 * of swizzling perf_event::ctx.
10332 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10333 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10335 perf_remove_from_context(event, 0);
10336 unaccount_event_cpu(event, src_cpu);
10338 list_add(&event->migrate_entry, &events);
10342 * Wait for the events to quiesce before re-instating them.
10347 * Re-instate events in 2 passes.
10349 * Skip over group leaders and only install siblings on this first
10350 * pass, siblings will not get enabled without a leader, however a
10351 * leader will enable its siblings, even if those are still on the old
10354 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10355 if (event->group_leader == event)
10358 list_del(&event->migrate_entry);
10359 if (event->state >= PERF_EVENT_STATE_OFF)
10360 event->state = PERF_EVENT_STATE_INACTIVE;
10361 account_event_cpu(event, dst_cpu);
10362 perf_install_in_context(dst_ctx, event, dst_cpu);
10367 * Once all the siblings are setup properly, install the group leaders
10370 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10371 list_del(&event->migrate_entry);
10372 if (event->state >= PERF_EVENT_STATE_OFF)
10373 event->state = PERF_EVENT_STATE_INACTIVE;
10374 account_event_cpu(event, dst_cpu);
10375 perf_install_in_context(dst_ctx, event, dst_cpu);
10378 mutex_unlock(&dst_ctx->mutex);
10379 mutex_unlock(&src_ctx->mutex);
10381 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10383 static void sync_child_event(struct perf_event *child_event,
10384 struct task_struct *child)
10386 struct perf_event *parent_event = child_event->parent;
10389 if (child_event->attr.inherit_stat)
10390 perf_event_read_event(child_event, child);
10392 child_val = perf_event_count(child_event);
10395 * Add back the child's count to the parent's count:
10397 atomic64_add(child_val, &parent_event->child_count);
10398 atomic64_add(child_event->total_time_enabled,
10399 &parent_event->child_total_time_enabled);
10400 atomic64_add(child_event->total_time_running,
10401 &parent_event->child_total_time_running);
10405 perf_event_exit_event(struct perf_event *child_event,
10406 struct perf_event_context *child_ctx,
10407 struct task_struct *child)
10409 struct perf_event *parent_event = child_event->parent;
10412 * Do not destroy the 'original' grouping; because of the context
10413 * switch optimization the original events could've ended up in a
10414 * random child task.
10416 * If we were to destroy the original group, all group related
10417 * operations would cease to function properly after this random
10420 * Do destroy all inherited groups, we don't care about those
10421 * and being thorough is better.
10423 raw_spin_lock_irq(&child_ctx->lock);
10424 WARN_ON_ONCE(child_ctx->is_active);
10427 perf_group_detach(child_event);
10428 list_del_event(child_event, child_ctx);
10429 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10430 raw_spin_unlock_irq(&child_ctx->lock);
10433 * Parent events are governed by their filedesc, retain them.
10435 if (!parent_event) {
10436 perf_event_wakeup(child_event);
10440 * Child events can be cleaned up.
10443 sync_child_event(child_event, child);
10446 * Remove this event from the parent's list
10448 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10449 mutex_lock(&parent_event->child_mutex);
10450 list_del_init(&child_event->child_list);
10451 mutex_unlock(&parent_event->child_mutex);
10454 * Kick perf_poll() for is_event_hup().
10456 perf_event_wakeup(parent_event);
10457 free_event(child_event);
10458 put_event(parent_event);
10461 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10463 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10464 struct perf_event *child_event, *next;
10466 WARN_ON_ONCE(child != current);
10468 child_ctx = perf_pin_task_context(child, ctxn);
10473 * In order to reduce the amount of tricky in ctx tear-down, we hold
10474 * ctx::mutex over the entire thing. This serializes against almost
10475 * everything that wants to access the ctx.
10477 * The exception is sys_perf_event_open() /
10478 * perf_event_create_kernel_count() which does find_get_context()
10479 * without ctx::mutex (it cannot because of the move_group double mutex
10480 * lock thing). See the comments in perf_install_in_context().
10482 mutex_lock(&child_ctx->mutex);
10485 * In a single ctx::lock section, de-schedule the events and detach the
10486 * context from the task such that we cannot ever get it scheduled back
10489 raw_spin_lock_irq(&child_ctx->lock);
10490 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10493 * Now that the context is inactive, destroy the task <-> ctx relation
10494 * and mark the context dead.
10496 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10497 put_ctx(child_ctx); /* cannot be last */
10498 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10499 put_task_struct(current); /* cannot be last */
10501 clone_ctx = unclone_ctx(child_ctx);
10502 raw_spin_unlock_irq(&child_ctx->lock);
10505 put_ctx(clone_ctx);
10508 * Report the task dead after unscheduling the events so that we
10509 * won't get any samples after PERF_RECORD_EXIT. We can however still
10510 * get a few PERF_RECORD_READ events.
10512 perf_event_task(child, child_ctx, 0);
10514 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10515 perf_event_exit_event(child_event, child_ctx, child);
10517 mutex_unlock(&child_ctx->mutex);
10519 put_ctx(child_ctx);
10523 * When a child task exits, feed back event values to parent events.
10525 * Can be called with cred_guard_mutex held when called from
10526 * install_exec_creds().
10528 void perf_event_exit_task(struct task_struct *child)
10530 struct perf_event *event, *tmp;
10533 mutex_lock(&child->perf_event_mutex);
10534 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10536 list_del_init(&event->owner_entry);
10539 * Ensure the list deletion is visible before we clear
10540 * the owner, closes a race against perf_release() where
10541 * we need to serialize on the owner->perf_event_mutex.
10543 smp_store_release(&event->owner, NULL);
10545 mutex_unlock(&child->perf_event_mutex);
10547 for_each_task_context_nr(ctxn)
10548 perf_event_exit_task_context(child, ctxn);
10551 * The perf_event_exit_task_context calls perf_event_task
10552 * with child's task_ctx, which generates EXIT events for
10553 * child contexts and sets child->perf_event_ctxp[] to NULL.
10554 * At this point we need to send EXIT events to cpu contexts.
10556 perf_event_task(child, NULL, 0);
10559 static void perf_free_event(struct perf_event *event,
10560 struct perf_event_context *ctx)
10562 struct perf_event *parent = event->parent;
10564 if (WARN_ON_ONCE(!parent))
10567 mutex_lock(&parent->child_mutex);
10568 list_del_init(&event->child_list);
10569 mutex_unlock(&parent->child_mutex);
10573 raw_spin_lock_irq(&ctx->lock);
10574 perf_group_detach(event);
10575 list_del_event(event, ctx);
10576 raw_spin_unlock_irq(&ctx->lock);
10581 * Free an unexposed, unused context as created by inheritance by
10582 * perf_event_init_task below, used by fork() in case of fail.
10584 * Not all locks are strictly required, but take them anyway to be nice and
10585 * help out with the lockdep assertions.
10587 void perf_event_free_task(struct task_struct *task)
10589 struct perf_event_context *ctx;
10590 struct perf_event *event, *tmp;
10593 for_each_task_context_nr(ctxn) {
10594 ctx = task->perf_event_ctxp[ctxn];
10598 mutex_lock(&ctx->mutex);
10599 raw_spin_lock_irq(&ctx->lock);
10601 * Destroy the task <-> ctx relation and mark the context dead.
10603 * This is important because even though the task hasn't been
10604 * exposed yet the context has been (through child_list).
10606 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10607 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10608 put_task_struct(task); /* cannot be last */
10609 raw_spin_unlock_irq(&ctx->lock);
10611 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10612 perf_free_event(event, ctx);
10614 mutex_unlock(&ctx->mutex);
10619 void perf_event_delayed_put(struct task_struct *task)
10623 for_each_task_context_nr(ctxn)
10624 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10627 struct file *perf_event_get(unsigned int fd)
10631 file = fget_raw(fd);
10633 return ERR_PTR(-EBADF);
10635 if (file->f_op != &perf_fops) {
10637 return ERR_PTR(-EBADF);
10643 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10646 return ERR_PTR(-EINVAL);
10648 return &event->attr;
10652 * Inherit a event from parent task to child task.
10655 * - valid pointer on success
10656 * - NULL for orphaned events
10657 * - IS_ERR() on error
10659 static struct perf_event *
10660 inherit_event(struct perf_event *parent_event,
10661 struct task_struct *parent,
10662 struct perf_event_context *parent_ctx,
10663 struct task_struct *child,
10664 struct perf_event *group_leader,
10665 struct perf_event_context *child_ctx)
10667 enum perf_event_active_state parent_state = parent_event->state;
10668 struct perf_event *child_event;
10669 unsigned long flags;
10672 * Instead of creating recursive hierarchies of events,
10673 * we link inherited events back to the original parent,
10674 * which has a filp for sure, which we use as the reference
10677 if (parent_event->parent)
10678 parent_event = parent_event->parent;
10680 child_event = perf_event_alloc(&parent_event->attr,
10683 group_leader, parent_event,
10685 if (IS_ERR(child_event))
10686 return child_event;
10689 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10690 * must be under the same lock in order to serialize against
10691 * perf_event_release_kernel(), such that either we must observe
10692 * is_orphaned_event() or they will observe us on the child_list.
10694 mutex_lock(&parent_event->child_mutex);
10695 if (is_orphaned_event(parent_event) ||
10696 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10697 mutex_unlock(&parent_event->child_mutex);
10698 free_event(child_event);
10702 get_ctx(child_ctx);
10705 * Make the child state follow the state of the parent event,
10706 * not its attr.disabled bit. We hold the parent's mutex,
10707 * so we won't race with perf_event_{en, dis}able_family.
10709 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10710 child_event->state = PERF_EVENT_STATE_INACTIVE;
10712 child_event->state = PERF_EVENT_STATE_OFF;
10714 if (parent_event->attr.freq) {
10715 u64 sample_period = parent_event->hw.sample_period;
10716 struct hw_perf_event *hwc = &child_event->hw;
10718 hwc->sample_period = sample_period;
10719 hwc->last_period = sample_period;
10721 local64_set(&hwc->period_left, sample_period);
10724 child_event->ctx = child_ctx;
10725 child_event->overflow_handler = parent_event->overflow_handler;
10726 child_event->overflow_handler_context
10727 = parent_event->overflow_handler_context;
10730 * Precalculate sample_data sizes
10732 perf_event__header_size(child_event);
10733 perf_event__id_header_size(child_event);
10736 * Link it up in the child's context:
10738 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10739 add_event_to_ctx(child_event, child_ctx);
10740 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10743 * Link this into the parent event's child list
10745 list_add_tail(&child_event->child_list, &parent_event->child_list);
10746 mutex_unlock(&parent_event->child_mutex);
10748 return child_event;
10752 * Inherits an event group.
10754 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10755 * This matches with perf_event_release_kernel() removing all child events.
10761 static int inherit_group(struct perf_event *parent_event,
10762 struct task_struct *parent,
10763 struct perf_event_context *parent_ctx,
10764 struct task_struct *child,
10765 struct perf_event_context *child_ctx)
10767 struct perf_event *leader;
10768 struct perf_event *sub;
10769 struct perf_event *child_ctr;
10771 leader = inherit_event(parent_event, parent, parent_ctx,
10772 child, NULL, child_ctx);
10773 if (IS_ERR(leader))
10774 return PTR_ERR(leader);
10776 * @leader can be NULL here because of is_orphaned_event(). In this
10777 * case inherit_event() will create individual events, similar to what
10778 * perf_group_detach() would do anyway.
10780 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10781 child_ctr = inherit_event(sub, parent, parent_ctx,
10782 child, leader, child_ctx);
10783 if (IS_ERR(child_ctr))
10784 return PTR_ERR(child_ctr);
10790 * Creates the child task context and tries to inherit the event-group.
10792 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10793 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10794 * consistent with perf_event_release_kernel() removing all child events.
10801 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10802 struct perf_event_context *parent_ctx,
10803 struct task_struct *child, int ctxn,
10804 int *inherited_all)
10807 struct perf_event_context *child_ctx;
10809 if (!event->attr.inherit) {
10810 *inherited_all = 0;
10814 child_ctx = child->perf_event_ctxp[ctxn];
10817 * This is executed from the parent task context, so
10818 * inherit events that have been marked for cloning.
10819 * First allocate and initialize a context for the
10822 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10826 child->perf_event_ctxp[ctxn] = child_ctx;
10829 ret = inherit_group(event, parent, parent_ctx,
10833 *inherited_all = 0;
10839 * Initialize the perf_event context in task_struct
10841 static int perf_event_init_context(struct task_struct *child, int ctxn)
10843 struct perf_event_context *child_ctx, *parent_ctx;
10844 struct perf_event_context *cloned_ctx;
10845 struct perf_event *event;
10846 struct task_struct *parent = current;
10847 int inherited_all = 1;
10848 unsigned long flags;
10851 if (likely(!parent->perf_event_ctxp[ctxn]))
10855 * If the parent's context is a clone, pin it so it won't get
10856 * swapped under us.
10858 parent_ctx = perf_pin_task_context(parent, ctxn);
10863 * No need to check if parent_ctx != NULL here; since we saw
10864 * it non-NULL earlier, the only reason for it to become NULL
10865 * is if we exit, and since we're currently in the middle of
10866 * a fork we can't be exiting at the same time.
10870 * Lock the parent list. No need to lock the child - not PID
10871 * hashed yet and not running, so nobody can access it.
10873 mutex_lock(&parent_ctx->mutex);
10876 * We dont have to disable NMIs - we are only looking at
10877 * the list, not manipulating it:
10879 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10880 ret = inherit_task_group(event, parent, parent_ctx,
10881 child, ctxn, &inherited_all);
10887 * We can't hold ctx->lock when iterating the ->flexible_group list due
10888 * to allocations, but we need to prevent rotation because
10889 * rotate_ctx() will change the list from interrupt context.
10891 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10892 parent_ctx->rotate_disable = 1;
10893 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10895 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10896 ret = inherit_task_group(event, parent, parent_ctx,
10897 child, ctxn, &inherited_all);
10902 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10903 parent_ctx->rotate_disable = 0;
10905 child_ctx = child->perf_event_ctxp[ctxn];
10907 if (child_ctx && inherited_all) {
10909 * Mark the child context as a clone of the parent
10910 * context, or of whatever the parent is a clone of.
10912 * Note that if the parent is a clone, the holding of
10913 * parent_ctx->lock avoids it from being uncloned.
10915 cloned_ctx = parent_ctx->parent_ctx;
10917 child_ctx->parent_ctx = cloned_ctx;
10918 child_ctx->parent_gen = parent_ctx->parent_gen;
10920 child_ctx->parent_ctx = parent_ctx;
10921 child_ctx->parent_gen = parent_ctx->generation;
10923 get_ctx(child_ctx->parent_ctx);
10926 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10928 mutex_unlock(&parent_ctx->mutex);
10930 perf_unpin_context(parent_ctx);
10931 put_ctx(parent_ctx);
10937 * Initialize the perf_event context in task_struct
10939 int perf_event_init_task(struct task_struct *child)
10943 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10944 mutex_init(&child->perf_event_mutex);
10945 INIT_LIST_HEAD(&child->perf_event_list);
10947 for_each_task_context_nr(ctxn) {
10948 ret = perf_event_init_context(child, ctxn);
10950 perf_event_free_task(child);
10958 static void __init perf_event_init_all_cpus(void)
10960 struct swevent_htable *swhash;
10963 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
10965 for_each_possible_cpu(cpu) {
10966 swhash = &per_cpu(swevent_htable, cpu);
10967 mutex_init(&swhash->hlist_mutex);
10968 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10970 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10971 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10973 #ifdef CONFIG_CGROUP_PERF
10974 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10976 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10980 void perf_swevent_init_cpu(unsigned int cpu)
10982 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10984 mutex_lock(&swhash->hlist_mutex);
10985 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10986 struct swevent_hlist *hlist;
10988 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10990 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10992 mutex_unlock(&swhash->hlist_mutex);
10995 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10996 static void __perf_event_exit_context(void *__info)
10998 struct perf_event_context *ctx = __info;
10999 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11000 struct perf_event *event;
11002 raw_spin_lock(&ctx->lock);
11003 list_for_each_entry(event, &ctx->event_list, event_entry)
11004 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11005 raw_spin_unlock(&ctx->lock);
11008 static void perf_event_exit_cpu_context(int cpu)
11010 struct perf_cpu_context *cpuctx;
11011 struct perf_event_context *ctx;
11014 mutex_lock(&pmus_lock);
11015 list_for_each_entry(pmu, &pmus, entry) {
11016 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11017 ctx = &cpuctx->ctx;
11019 mutex_lock(&ctx->mutex);
11020 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11021 cpuctx->online = 0;
11022 mutex_unlock(&ctx->mutex);
11024 cpumask_clear_cpu(cpu, perf_online_mask);
11025 mutex_unlock(&pmus_lock);
11029 static void perf_event_exit_cpu_context(int cpu) { }
11033 int perf_event_init_cpu(unsigned int cpu)
11035 struct perf_cpu_context *cpuctx;
11036 struct perf_event_context *ctx;
11039 perf_swevent_init_cpu(cpu);
11041 mutex_lock(&pmus_lock);
11042 cpumask_set_cpu(cpu, perf_online_mask);
11043 list_for_each_entry(pmu, &pmus, entry) {
11044 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11045 ctx = &cpuctx->ctx;
11047 mutex_lock(&ctx->mutex);
11048 cpuctx->online = 1;
11049 mutex_unlock(&ctx->mutex);
11051 mutex_unlock(&pmus_lock);
11056 int perf_event_exit_cpu(unsigned int cpu)
11058 perf_event_exit_cpu_context(cpu);
11063 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11067 for_each_online_cpu(cpu)
11068 perf_event_exit_cpu(cpu);
11074 * Run the perf reboot notifier at the very last possible moment so that
11075 * the generic watchdog code runs as long as possible.
11077 static struct notifier_block perf_reboot_notifier = {
11078 .notifier_call = perf_reboot,
11079 .priority = INT_MIN,
11082 void __init perf_event_init(void)
11086 idr_init(&pmu_idr);
11088 perf_event_init_all_cpus();
11089 init_srcu_struct(&pmus_srcu);
11090 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11091 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11092 perf_pmu_register(&perf_task_clock, NULL, -1);
11093 perf_tp_register();
11094 perf_event_init_cpu(smp_processor_id());
11095 register_reboot_notifier(&perf_reboot_notifier);
11097 ret = init_hw_breakpoint();
11098 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11101 * Build time assertion that we keep the data_head at the intended
11102 * location. IOW, validation we got the __reserved[] size right.
11104 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11108 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11111 struct perf_pmu_events_attr *pmu_attr =
11112 container_of(attr, struct perf_pmu_events_attr, attr);
11114 if (pmu_attr->event_str)
11115 return sprintf(page, "%s\n", pmu_attr->event_str);
11119 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11121 static int __init perf_event_sysfs_init(void)
11126 mutex_lock(&pmus_lock);
11128 ret = bus_register(&pmu_bus);
11132 list_for_each_entry(pmu, &pmus, entry) {
11133 if (!pmu->name || pmu->type < 0)
11136 ret = pmu_dev_alloc(pmu);
11137 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11139 pmu_bus_running = 1;
11143 mutex_unlock(&pmus_lock);
11147 device_initcall(perf_event_sysfs_init);
11149 #ifdef CONFIG_CGROUP_PERF
11150 static struct cgroup_subsys_state *
11151 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11153 struct perf_cgroup *jc;
11155 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11157 return ERR_PTR(-ENOMEM);
11159 jc->info = alloc_percpu(struct perf_cgroup_info);
11162 return ERR_PTR(-ENOMEM);
11168 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11170 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11172 free_percpu(jc->info);
11176 static int __perf_cgroup_move(void *info)
11178 struct task_struct *task = info;
11180 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11185 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11187 struct task_struct *task;
11188 struct cgroup_subsys_state *css;
11190 cgroup_taskset_for_each(task, css, tset)
11191 task_function_call(task, __perf_cgroup_move, task);
11194 struct cgroup_subsys perf_event_cgrp_subsys = {
11195 .css_alloc = perf_cgroup_css_alloc,
11196 .css_free = perf_cgroup_css_free,
11197 .attach = perf_cgroup_attach,
11199 * Implicitly enable on dfl hierarchy so that perf events can
11200 * always be filtered by cgroup2 path as long as perf_event
11201 * controller is not mounted on a legacy hierarchy.
11203 .implicit_on_dfl = true,
11205 #endif /* CONFIG_CGROUP_PERF */