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 lockdep_assert_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 lockdep_assert_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();
586 * State based event timekeeping...
588 * The basic idea is to use event->state to determine which (if any) time
589 * fields to increment with the current delta. This means we only need to
590 * update timestamps when we change state or when they are explicitly requested
593 * Event groups make things a little more complicated, but not terribly so. The
594 * rules for a group are that if the group leader is OFF the entire group is
595 * OFF, irrespecive of what the group member states are. This results in
596 * __perf_effective_state().
598 * A futher ramification is that when a group leader flips between OFF and
599 * !OFF, we need to update all group member times.
602 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
603 * need to make sure the relevant context time is updated before we try and
604 * update our timestamps.
607 static __always_inline enum perf_event_state
608 __perf_effective_state(struct perf_event *event)
610 struct perf_event *leader = event->group_leader;
612 if (leader->state <= PERF_EVENT_STATE_OFF)
613 return leader->state;
618 static __always_inline void
619 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
621 enum perf_event_state state = __perf_effective_state(event);
622 u64 delta = now - event->tstamp;
624 *enabled = event->total_time_enabled;
625 if (state >= PERF_EVENT_STATE_INACTIVE)
628 *running = event->total_time_running;
629 if (state >= PERF_EVENT_STATE_ACTIVE)
633 static void perf_event_update_time(struct perf_event *event)
635 u64 now = perf_event_time(event);
637 __perf_update_times(event, now, &event->total_time_enabled,
638 &event->total_time_running);
642 static void perf_event_update_sibling_time(struct perf_event *leader)
644 struct perf_event *sibling;
646 list_for_each_entry(sibling, &leader->sibling_list, group_entry)
647 perf_event_update_time(sibling);
651 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
653 if (event->state == state)
656 perf_event_update_time(event);
658 * If a group leader gets enabled/disabled all its siblings
661 if ((event->state < 0) ^ (state < 0))
662 perf_event_update_sibling_time(event);
664 WRITE_ONCE(event->state, state);
667 #ifdef CONFIG_CGROUP_PERF
670 perf_cgroup_match(struct perf_event *event)
672 struct perf_event_context *ctx = event->ctx;
673 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
675 /* @event doesn't care about cgroup */
679 /* wants specific cgroup scope but @cpuctx isn't associated with any */
684 * Cgroup scoping is recursive. An event enabled for a cgroup is
685 * also enabled for all its descendant cgroups. If @cpuctx's
686 * cgroup is a descendant of @event's (the test covers identity
687 * case), it's a match.
689 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
690 event->cgrp->css.cgroup);
693 static inline void perf_detach_cgroup(struct perf_event *event)
695 css_put(&event->cgrp->css);
699 static inline int is_cgroup_event(struct perf_event *event)
701 return event->cgrp != NULL;
704 static inline u64 perf_cgroup_event_time(struct perf_event *event)
706 struct perf_cgroup_info *t;
708 t = per_cpu_ptr(event->cgrp->info, event->cpu);
712 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
714 struct perf_cgroup_info *info;
719 info = this_cpu_ptr(cgrp->info);
721 info->time += now - info->timestamp;
722 info->timestamp = now;
725 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
727 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
729 __update_cgrp_time(cgrp_out);
732 static inline void update_cgrp_time_from_event(struct perf_event *event)
734 struct perf_cgroup *cgrp;
737 * ensure we access cgroup data only when needed and
738 * when we know the cgroup is pinned (css_get)
740 if (!is_cgroup_event(event))
743 cgrp = perf_cgroup_from_task(current, event->ctx);
745 * Do not update time when cgroup is not active
747 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
748 __update_cgrp_time(event->cgrp);
752 perf_cgroup_set_timestamp(struct task_struct *task,
753 struct perf_event_context *ctx)
755 struct perf_cgroup *cgrp;
756 struct perf_cgroup_info *info;
759 * ctx->lock held by caller
760 * ensure we do not access cgroup data
761 * unless we have the cgroup pinned (css_get)
763 if (!task || !ctx->nr_cgroups)
766 cgrp = perf_cgroup_from_task(task, ctx);
767 info = this_cpu_ptr(cgrp->info);
768 info->timestamp = ctx->timestamp;
771 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
773 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
774 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
777 * reschedule events based on the cgroup constraint of task.
779 * mode SWOUT : schedule out everything
780 * mode SWIN : schedule in based on cgroup for next
782 static void perf_cgroup_switch(struct task_struct *task, int mode)
784 struct perf_cpu_context *cpuctx;
785 struct list_head *list;
789 * Disable interrupts and preemption to avoid this CPU's
790 * cgrp_cpuctx_entry to change under us.
792 local_irq_save(flags);
794 list = this_cpu_ptr(&cgrp_cpuctx_list);
795 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
796 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
798 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
799 perf_pmu_disable(cpuctx->ctx.pmu);
801 if (mode & PERF_CGROUP_SWOUT) {
802 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
804 * must not be done before ctxswout due
805 * to event_filter_match() in event_sched_out()
810 if (mode & PERF_CGROUP_SWIN) {
811 WARN_ON_ONCE(cpuctx->cgrp);
813 * set cgrp before ctxsw in to allow
814 * event_filter_match() to not have to pass
816 * we pass the cpuctx->ctx to perf_cgroup_from_task()
817 * because cgorup events are only per-cpu
819 cpuctx->cgrp = perf_cgroup_from_task(task,
821 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
823 perf_pmu_enable(cpuctx->ctx.pmu);
824 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
827 local_irq_restore(flags);
830 static inline void perf_cgroup_sched_out(struct task_struct *task,
831 struct task_struct *next)
833 struct perf_cgroup *cgrp1;
834 struct perf_cgroup *cgrp2 = NULL;
838 * we come here when we know perf_cgroup_events > 0
839 * we do not need to pass the ctx here because we know
840 * we are holding the rcu lock
842 cgrp1 = perf_cgroup_from_task(task, NULL);
843 cgrp2 = perf_cgroup_from_task(next, NULL);
846 * only schedule out current cgroup events if we know
847 * that we are switching to a different cgroup. Otherwise,
848 * do no touch the cgroup events.
851 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
856 static inline void perf_cgroup_sched_in(struct task_struct *prev,
857 struct task_struct *task)
859 struct perf_cgroup *cgrp1;
860 struct perf_cgroup *cgrp2 = NULL;
864 * we come here when we know perf_cgroup_events > 0
865 * we do not need to pass the ctx here because we know
866 * we are holding the rcu lock
868 cgrp1 = perf_cgroup_from_task(task, NULL);
869 cgrp2 = perf_cgroup_from_task(prev, NULL);
872 * only need to schedule in cgroup events if we are changing
873 * cgroup during ctxsw. Cgroup events were not scheduled
874 * out of ctxsw out if that was not the case.
877 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
882 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
883 struct perf_event_attr *attr,
884 struct perf_event *group_leader)
886 struct perf_cgroup *cgrp;
887 struct cgroup_subsys_state *css;
888 struct fd f = fdget(fd);
894 css = css_tryget_online_from_dir(f.file->f_path.dentry,
895 &perf_event_cgrp_subsys);
901 cgrp = container_of(css, struct perf_cgroup, css);
905 * all events in a group must monitor
906 * the same cgroup because a task belongs
907 * to only one perf cgroup at a time
909 if (group_leader && group_leader->cgrp != cgrp) {
910 perf_detach_cgroup(event);
919 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
921 struct perf_cgroup_info *t;
922 t = per_cpu_ptr(event->cgrp->info, event->cpu);
923 event->shadow_ctx_time = now - t->timestamp;
927 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
928 * cleared when last cgroup event is removed.
931 list_update_cgroup_event(struct perf_event *event,
932 struct perf_event_context *ctx, bool add)
934 struct perf_cpu_context *cpuctx;
935 struct list_head *cpuctx_entry;
937 if (!is_cgroup_event(event))
940 if (add && ctx->nr_cgroups++)
942 else if (!add && --ctx->nr_cgroups)
945 * Because cgroup events are always per-cpu events,
946 * this will always be called from the right CPU.
948 cpuctx = __get_cpu_context(ctx);
949 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
950 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
952 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
954 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
955 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
958 list_del(cpuctx_entry);
963 #else /* !CONFIG_CGROUP_PERF */
966 perf_cgroup_match(struct perf_event *event)
971 static inline void perf_detach_cgroup(struct perf_event *event)
974 static inline int is_cgroup_event(struct perf_event *event)
979 static inline void update_cgrp_time_from_event(struct perf_event *event)
983 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
987 static inline void perf_cgroup_sched_out(struct task_struct *task,
988 struct task_struct *next)
992 static inline void perf_cgroup_sched_in(struct task_struct *prev,
993 struct task_struct *task)
997 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
998 struct perf_event_attr *attr,
999 struct perf_event *group_leader)
1005 perf_cgroup_set_timestamp(struct task_struct *task,
1006 struct perf_event_context *ctx)
1011 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1016 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1020 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1026 list_update_cgroup_event(struct perf_event *event,
1027 struct perf_event_context *ctx, bool add)
1034 * set default to be dependent on timer tick just
1035 * like original code
1037 #define PERF_CPU_HRTIMER (1000 / HZ)
1039 * function must be called with interrupts disabled
1041 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1043 struct perf_cpu_context *cpuctx;
1046 lockdep_assert_irqs_disabled();
1048 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1049 rotations = perf_rotate_context(cpuctx);
1051 raw_spin_lock(&cpuctx->hrtimer_lock);
1053 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1055 cpuctx->hrtimer_active = 0;
1056 raw_spin_unlock(&cpuctx->hrtimer_lock);
1058 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1061 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1063 struct hrtimer *timer = &cpuctx->hrtimer;
1064 struct pmu *pmu = cpuctx->ctx.pmu;
1067 /* no multiplexing needed for SW PMU */
1068 if (pmu->task_ctx_nr == perf_sw_context)
1072 * check default is sane, if not set then force to
1073 * default interval (1/tick)
1075 interval = pmu->hrtimer_interval_ms;
1077 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1079 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1081 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1082 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1083 timer->function = perf_mux_hrtimer_handler;
1086 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1088 struct hrtimer *timer = &cpuctx->hrtimer;
1089 struct pmu *pmu = cpuctx->ctx.pmu;
1090 unsigned long flags;
1092 /* not for SW PMU */
1093 if (pmu->task_ctx_nr == perf_sw_context)
1096 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1097 if (!cpuctx->hrtimer_active) {
1098 cpuctx->hrtimer_active = 1;
1099 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1100 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1102 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1107 void perf_pmu_disable(struct pmu *pmu)
1109 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1111 pmu->pmu_disable(pmu);
1114 void perf_pmu_enable(struct pmu *pmu)
1116 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1118 pmu->pmu_enable(pmu);
1121 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1124 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1125 * perf_event_task_tick() are fully serialized because they're strictly cpu
1126 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1127 * disabled, while perf_event_task_tick is called from IRQ context.
1129 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1131 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1133 lockdep_assert_irqs_disabled();
1135 WARN_ON(!list_empty(&ctx->active_ctx_list));
1137 list_add(&ctx->active_ctx_list, head);
1140 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1142 lockdep_assert_irqs_disabled();
1144 WARN_ON(list_empty(&ctx->active_ctx_list));
1146 list_del_init(&ctx->active_ctx_list);
1149 static void get_ctx(struct perf_event_context *ctx)
1151 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1154 static void free_ctx(struct rcu_head *head)
1156 struct perf_event_context *ctx;
1158 ctx = container_of(head, struct perf_event_context, rcu_head);
1159 kfree(ctx->task_ctx_data);
1163 static void put_ctx(struct perf_event_context *ctx)
1165 if (atomic_dec_and_test(&ctx->refcount)) {
1166 if (ctx->parent_ctx)
1167 put_ctx(ctx->parent_ctx);
1168 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1169 put_task_struct(ctx->task);
1170 call_rcu(&ctx->rcu_head, free_ctx);
1175 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1176 * perf_pmu_migrate_context() we need some magic.
1178 * Those places that change perf_event::ctx will hold both
1179 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1181 * Lock ordering is by mutex address. There are two other sites where
1182 * perf_event_context::mutex nests and those are:
1184 * - perf_event_exit_task_context() [ child , 0 ]
1185 * perf_event_exit_event()
1186 * put_event() [ parent, 1 ]
1188 * - perf_event_init_context() [ parent, 0 ]
1189 * inherit_task_group()
1192 * perf_event_alloc()
1194 * perf_try_init_event() [ child , 1 ]
1196 * While it appears there is an obvious deadlock here -- the parent and child
1197 * nesting levels are inverted between the two. This is in fact safe because
1198 * life-time rules separate them. That is an exiting task cannot fork, and a
1199 * spawning task cannot (yet) exit.
1201 * But remember that that these are parent<->child context relations, and
1202 * migration does not affect children, therefore these two orderings should not
1205 * The change in perf_event::ctx does not affect children (as claimed above)
1206 * because the sys_perf_event_open() case will install a new event and break
1207 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1208 * concerned with cpuctx and that doesn't have children.
1210 * The places that change perf_event::ctx will issue:
1212 * perf_remove_from_context();
1213 * synchronize_rcu();
1214 * perf_install_in_context();
1216 * to affect the change. The remove_from_context() + synchronize_rcu() should
1217 * quiesce the event, after which we can install it in the new location. This
1218 * means that only external vectors (perf_fops, prctl) can perturb the event
1219 * while in transit. Therefore all such accessors should also acquire
1220 * perf_event_context::mutex to serialize against this.
1222 * However; because event->ctx can change while we're waiting to acquire
1223 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1228 * task_struct::perf_event_mutex
1229 * perf_event_context::mutex
1230 * perf_event::child_mutex;
1231 * perf_event_context::lock
1232 * perf_event::mmap_mutex
1235 static struct perf_event_context *
1236 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1238 struct perf_event_context *ctx;
1242 ctx = READ_ONCE(event->ctx);
1243 if (!atomic_inc_not_zero(&ctx->refcount)) {
1249 mutex_lock_nested(&ctx->mutex, nesting);
1250 if (event->ctx != ctx) {
1251 mutex_unlock(&ctx->mutex);
1259 static inline struct perf_event_context *
1260 perf_event_ctx_lock(struct perf_event *event)
1262 return perf_event_ctx_lock_nested(event, 0);
1265 static void perf_event_ctx_unlock(struct perf_event *event,
1266 struct perf_event_context *ctx)
1268 mutex_unlock(&ctx->mutex);
1273 * This must be done under the ctx->lock, such as to serialize against
1274 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1275 * calling scheduler related locks and ctx->lock nests inside those.
1277 static __must_check struct perf_event_context *
1278 unclone_ctx(struct perf_event_context *ctx)
1280 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1282 lockdep_assert_held(&ctx->lock);
1285 ctx->parent_ctx = NULL;
1291 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1296 * only top level events have the pid namespace they were created in
1299 event = event->parent;
1301 nr = __task_pid_nr_ns(p, type, event->ns);
1302 /* avoid -1 if it is idle thread or runs in another ns */
1303 if (!nr && !pid_alive(p))
1308 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1310 return perf_event_pid_type(event, p, __PIDTYPE_TGID);
1313 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1315 return perf_event_pid_type(event, p, PIDTYPE_PID);
1319 * If we inherit events we want to return the parent event id
1322 static u64 primary_event_id(struct perf_event *event)
1327 id = event->parent->id;
1333 * Get the perf_event_context for a task and lock it.
1335 * This has to cope with with the fact that until it is locked,
1336 * the context could get moved to another task.
1338 static struct perf_event_context *
1339 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1341 struct perf_event_context *ctx;
1345 * One of the few rules of preemptible RCU is that one cannot do
1346 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1347 * part of the read side critical section was irqs-enabled -- see
1348 * rcu_read_unlock_special().
1350 * Since ctx->lock nests under rq->lock we must ensure the entire read
1351 * side critical section has interrupts disabled.
1353 local_irq_save(*flags);
1355 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1358 * If this context is a clone of another, it might
1359 * get swapped for another underneath us by
1360 * perf_event_task_sched_out, though the
1361 * rcu_read_lock() protects us from any context
1362 * getting freed. Lock the context and check if it
1363 * got swapped before we could get the lock, and retry
1364 * if so. If we locked the right context, then it
1365 * can't get swapped on us any more.
1367 raw_spin_lock(&ctx->lock);
1368 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1369 raw_spin_unlock(&ctx->lock);
1371 local_irq_restore(*flags);
1375 if (ctx->task == TASK_TOMBSTONE ||
1376 !atomic_inc_not_zero(&ctx->refcount)) {
1377 raw_spin_unlock(&ctx->lock);
1380 WARN_ON_ONCE(ctx->task != task);
1385 local_irq_restore(*flags);
1390 * Get the context for a task and increment its pin_count so it
1391 * can't get swapped to another task. This also increments its
1392 * reference count so that the context can't get freed.
1394 static struct perf_event_context *
1395 perf_pin_task_context(struct task_struct *task, int ctxn)
1397 struct perf_event_context *ctx;
1398 unsigned long flags;
1400 ctx = perf_lock_task_context(task, ctxn, &flags);
1403 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1408 static void perf_unpin_context(struct perf_event_context *ctx)
1410 unsigned long flags;
1412 raw_spin_lock_irqsave(&ctx->lock, flags);
1414 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1418 * Update the record of the current time in a context.
1420 static void update_context_time(struct perf_event_context *ctx)
1422 u64 now = perf_clock();
1424 ctx->time += now - ctx->timestamp;
1425 ctx->timestamp = now;
1428 static u64 perf_event_time(struct perf_event *event)
1430 struct perf_event_context *ctx = event->ctx;
1432 if (is_cgroup_event(event))
1433 return perf_cgroup_event_time(event);
1435 return ctx ? ctx->time : 0;
1438 static enum event_type_t get_event_type(struct perf_event *event)
1440 struct perf_event_context *ctx = event->ctx;
1441 enum event_type_t event_type;
1443 lockdep_assert_held(&ctx->lock);
1446 * It's 'group type', really, because if our group leader is
1447 * pinned, so are we.
1449 if (event->group_leader != event)
1450 event = event->group_leader;
1452 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1454 event_type |= EVENT_CPU;
1459 static struct list_head *
1460 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1462 if (event->attr.pinned)
1463 return &ctx->pinned_groups;
1465 return &ctx->flexible_groups;
1469 * Add a event from the lists for its context.
1470 * Must be called with ctx->mutex and ctx->lock held.
1473 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1475 lockdep_assert_held(&ctx->lock);
1477 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1478 event->attach_state |= PERF_ATTACH_CONTEXT;
1480 event->tstamp = perf_event_time(event);
1483 * If we're a stand alone event or group leader, we go to the context
1484 * list, group events are kept attached to the group so that
1485 * perf_group_detach can, at all times, locate all siblings.
1487 if (event->group_leader == event) {
1488 struct list_head *list;
1490 event->group_caps = event->event_caps;
1492 list = ctx_group_list(event, ctx);
1493 list_add_tail(&event->group_entry, list);
1496 list_update_cgroup_event(event, ctx, true);
1498 list_add_rcu(&event->event_entry, &ctx->event_list);
1500 if (event->attr.inherit_stat)
1507 * Initialize event state based on the perf_event_attr::disabled.
1509 static inline void perf_event__state_init(struct perf_event *event)
1511 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1512 PERF_EVENT_STATE_INACTIVE;
1515 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1517 int entry = sizeof(u64); /* value */
1521 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1522 size += sizeof(u64);
1524 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1525 size += sizeof(u64);
1527 if (event->attr.read_format & PERF_FORMAT_ID)
1528 entry += sizeof(u64);
1530 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1532 size += sizeof(u64);
1536 event->read_size = size;
1539 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1541 struct perf_sample_data *data;
1544 if (sample_type & PERF_SAMPLE_IP)
1545 size += sizeof(data->ip);
1547 if (sample_type & PERF_SAMPLE_ADDR)
1548 size += sizeof(data->addr);
1550 if (sample_type & PERF_SAMPLE_PERIOD)
1551 size += sizeof(data->period);
1553 if (sample_type & PERF_SAMPLE_WEIGHT)
1554 size += sizeof(data->weight);
1556 if (sample_type & PERF_SAMPLE_READ)
1557 size += event->read_size;
1559 if (sample_type & PERF_SAMPLE_DATA_SRC)
1560 size += sizeof(data->data_src.val);
1562 if (sample_type & PERF_SAMPLE_TRANSACTION)
1563 size += sizeof(data->txn);
1565 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1566 size += sizeof(data->phys_addr);
1568 event->header_size = size;
1572 * Called at perf_event creation and when events are attached/detached from a
1575 static void perf_event__header_size(struct perf_event *event)
1577 __perf_event_read_size(event,
1578 event->group_leader->nr_siblings);
1579 __perf_event_header_size(event, event->attr.sample_type);
1582 static void perf_event__id_header_size(struct perf_event *event)
1584 struct perf_sample_data *data;
1585 u64 sample_type = event->attr.sample_type;
1588 if (sample_type & PERF_SAMPLE_TID)
1589 size += sizeof(data->tid_entry);
1591 if (sample_type & PERF_SAMPLE_TIME)
1592 size += sizeof(data->time);
1594 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1595 size += sizeof(data->id);
1597 if (sample_type & PERF_SAMPLE_ID)
1598 size += sizeof(data->id);
1600 if (sample_type & PERF_SAMPLE_STREAM_ID)
1601 size += sizeof(data->stream_id);
1603 if (sample_type & PERF_SAMPLE_CPU)
1604 size += sizeof(data->cpu_entry);
1606 event->id_header_size = size;
1609 static bool perf_event_validate_size(struct perf_event *event)
1612 * The values computed here will be over-written when we actually
1615 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1616 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1617 perf_event__id_header_size(event);
1620 * Sum the lot; should not exceed the 64k limit we have on records.
1621 * Conservative limit to allow for callchains and other variable fields.
1623 if (event->read_size + event->header_size +
1624 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1630 static void perf_group_attach(struct perf_event *event)
1632 struct perf_event *group_leader = event->group_leader, *pos;
1634 lockdep_assert_held(&event->ctx->lock);
1637 * We can have double attach due to group movement in perf_event_open.
1639 if (event->attach_state & PERF_ATTACH_GROUP)
1642 event->attach_state |= PERF_ATTACH_GROUP;
1644 if (group_leader == event)
1647 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1649 group_leader->group_caps &= event->event_caps;
1651 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1652 group_leader->nr_siblings++;
1654 perf_event__header_size(group_leader);
1656 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1657 perf_event__header_size(pos);
1661 * Remove a event from the lists for its context.
1662 * Must be called with ctx->mutex and ctx->lock held.
1665 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1667 WARN_ON_ONCE(event->ctx != ctx);
1668 lockdep_assert_held(&ctx->lock);
1671 * We can have double detach due to exit/hot-unplug + close.
1673 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1676 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1678 list_update_cgroup_event(event, ctx, false);
1681 if (event->attr.inherit_stat)
1684 list_del_rcu(&event->event_entry);
1686 if (event->group_leader == event)
1687 list_del_init(&event->group_entry);
1690 * If event was in error state, then keep it
1691 * that way, otherwise bogus counts will be
1692 * returned on read(). The only way to get out
1693 * of error state is by explicit re-enabling
1696 if (event->state > PERF_EVENT_STATE_OFF)
1697 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1702 static void perf_group_detach(struct perf_event *event)
1704 struct perf_event *sibling, *tmp;
1705 struct list_head *list = NULL;
1707 lockdep_assert_held(&event->ctx->lock);
1710 * We can have double detach due to exit/hot-unplug + close.
1712 if (!(event->attach_state & PERF_ATTACH_GROUP))
1715 event->attach_state &= ~PERF_ATTACH_GROUP;
1718 * If this is a sibling, remove it from its group.
1720 if (event->group_leader != event) {
1721 list_del_init(&event->group_entry);
1722 event->group_leader->nr_siblings--;
1726 if (!list_empty(&event->group_entry))
1727 list = &event->group_entry;
1730 * If this was a group event with sibling events then
1731 * upgrade the siblings to singleton events by adding them
1732 * to whatever list we are on.
1734 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1736 list_move_tail(&sibling->group_entry, list);
1737 sibling->group_leader = sibling;
1739 /* Inherit group flags from the previous leader */
1740 sibling->group_caps = event->group_caps;
1742 WARN_ON_ONCE(sibling->ctx != event->ctx);
1746 perf_event__header_size(event->group_leader);
1748 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1749 perf_event__header_size(tmp);
1752 static bool is_orphaned_event(struct perf_event *event)
1754 return event->state == PERF_EVENT_STATE_DEAD;
1757 static inline int __pmu_filter_match(struct perf_event *event)
1759 struct pmu *pmu = event->pmu;
1760 return pmu->filter_match ? pmu->filter_match(event) : 1;
1764 * Check whether we should attempt to schedule an event group based on
1765 * PMU-specific filtering. An event group can consist of HW and SW events,
1766 * potentially with a SW leader, so we must check all the filters, to
1767 * determine whether a group is schedulable:
1769 static inline int pmu_filter_match(struct perf_event *event)
1771 struct perf_event *child;
1773 if (!__pmu_filter_match(event))
1776 list_for_each_entry(child, &event->sibling_list, group_entry) {
1777 if (!__pmu_filter_match(child))
1785 event_filter_match(struct perf_event *event)
1787 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1788 perf_cgroup_match(event) && pmu_filter_match(event);
1792 event_sched_out(struct perf_event *event,
1793 struct perf_cpu_context *cpuctx,
1794 struct perf_event_context *ctx)
1796 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1798 WARN_ON_ONCE(event->ctx != ctx);
1799 lockdep_assert_held(&ctx->lock);
1801 if (event->state != PERF_EVENT_STATE_ACTIVE)
1804 perf_pmu_disable(event->pmu);
1806 event->pmu->del(event, 0);
1809 if (event->pending_disable) {
1810 event->pending_disable = 0;
1811 state = PERF_EVENT_STATE_OFF;
1813 perf_event_set_state(event, state);
1815 if (!is_software_event(event))
1816 cpuctx->active_oncpu--;
1817 if (!--ctx->nr_active)
1818 perf_event_ctx_deactivate(ctx);
1819 if (event->attr.freq && event->attr.sample_freq)
1821 if (event->attr.exclusive || !cpuctx->active_oncpu)
1822 cpuctx->exclusive = 0;
1824 perf_pmu_enable(event->pmu);
1828 group_sched_out(struct perf_event *group_event,
1829 struct perf_cpu_context *cpuctx,
1830 struct perf_event_context *ctx)
1832 struct perf_event *event;
1834 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
1837 perf_pmu_disable(ctx->pmu);
1839 event_sched_out(group_event, cpuctx, ctx);
1842 * Schedule out siblings (if any):
1844 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1845 event_sched_out(event, cpuctx, ctx);
1847 perf_pmu_enable(ctx->pmu);
1849 if (group_event->attr.exclusive)
1850 cpuctx->exclusive = 0;
1853 #define DETACH_GROUP 0x01UL
1856 * Cross CPU call to remove a performance event
1858 * We disable the event on the hardware level first. After that we
1859 * remove it from the context list.
1862 __perf_remove_from_context(struct perf_event *event,
1863 struct perf_cpu_context *cpuctx,
1864 struct perf_event_context *ctx,
1867 unsigned long flags = (unsigned long)info;
1869 if (ctx->is_active & EVENT_TIME) {
1870 update_context_time(ctx);
1871 update_cgrp_time_from_cpuctx(cpuctx);
1874 event_sched_out(event, cpuctx, ctx);
1875 if (flags & DETACH_GROUP)
1876 perf_group_detach(event);
1877 list_del_event(event, ctx);
1879 if (!ctx->nr_events && ctx->is_active) {
1882 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1883 cpuctx->task_ctx = NULL;
1889 * Remove the event from a task's (or a CPU's) list of events.
1891 * If event->ctx is a cloned context, callers must make sure that
1892 * every task struct that event->ctx->task could possibly point to
1893 * remains valid. This is OK when called from perf_release since
1894 * that only calls us on the top-level context, which can't be a clone.
1895 * When called from perf_event_exit_task, it's OK because the
1896 * context has been detached from its task.
1898 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1900 struct perf_event_context *ctx = event->ctx;
1902 lockdep_assert_held(&ctx->mutex);
1904 event_function_call(event, __perf_remove_from_context, (void *)flags);
1907 * The above event_function_call() can NO-OP when it hits
1908 * TASK_TOMBSTONE. In that case we must already have been detached
1909 * from the context (by perf_event_exit_event()) but the grouping
1910 * might still be in-tact.
1912 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1913 if ((flags & DETACH_GROUP) &&
1914 (event->attach_state & PERF_ATTACH_GROUP)) {
1916 * Since in that case we cannot possibly be scheduled, simply
1919 raw_spin_lock_irq(&ctx->lock);
1920 perf_group_detach(event);
1921 raw_spin_unlock_irq(&ctx->lock);
1926 * Cross CPU call to disable a performance event
1928 static void __perf_event_disable(struct perf_event *event,
1929 struct perf_cpu_context *cpuctx,
1930 struct perf_event_context *ctx,
1933 if (event->state < PERF_EVENT_STATE_INACTIVE)
1936 if (ctx->is_active & EVENT_TIME) {
1937 update_context_time(ctx);
1938 update_cgrp_time_from_event(event);
1941 if (event == event->group_leader)
1942 group_sched_out(event, cpuctx, ctx);
1944 event_sched_out(event, cpuctx, ctx);
1946 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1952 * If event->ctx is a cloned context, callers must make sure that
1953 * every task struct that event->ctx->task could possibly point to
1954 * remains valid. This condition is satisifed when called through
1955 * perf_event_for_each_child or perf_event_for_each because they
1956 * hold the top-level event's child_mutex, so any descendant that
1957 * goes to exit will block in perf_event_exit_event().
1959 * When called from perf_pending_event it's OK because event->ctx
1960 * is the current context on this CPU and preemption is disabled,
1961 * hence we can't get into perf_event_task_sched_out for this context.
1963 static void _perf_event_disable(struct perf_event *event)
1965 struct perf_event_context *ctx = event->ctx;
1967 raw_spin_lock_irq(&ctx->lock);
1968 if (event->state <= PERF_EVENT_STATE_OFF) {
1969 raw_spin_unlock_irq(&ctx->lock);
1972 raw_spin_unlock_irq(&ctx->lock);
1974 event_function_call(event, __perf_event_disable, NULL);
1977 void perf_event_disable_local(struct perf_event *event)
1979 event_function_local(event, __perf_event_disable, NULL);
1983 * Strictly speaking kernel users cannot create groups and therefore this
1984 * interface does not need the perf_event_ctx_lock() magic.
1986 void perf_event_disable(struct perf_event *event)
1988 struct perf_event_context *ctx;
1990 ctx = perf_event_ctx_lock(event);
1991 _perf_event_disable(event);
1992 perf_event_ctx_unlock(event, ctx);
1994 EXPORT_SYMBOL_GPL(perf_event_disable);
1996 void perf_event_disable_inatomic(struct perf_event *event)
1998 event->pending_disable = 1;
1999 irq_work_queue(&event->pending);
2002 static void perf_set_shadow_time(struct perf_event *event,
2003 struct perf_event_context *ctx)
2006 * use the correct time source for the time snapshot
2008 * We could get by without this by leveraging the
2009 * fact that to get to this function, the caller
2010 * has most likely already called update_context_time()
2011 * and update_cgrp_time_xx() and thus both timestamp
2012 * are identical (or very close). Given that tstamp is,
2013 * already adjusted for cgroup, we could say that:
2014 * tstamp - ctx->timestamp
2016 * tstamp - cgrp->timestamp.
2018 * Then, in perf_output_read(), the calculation would
2019 * work with no changes because:
2020 * - event is guaranteed scheduled in
2021 * - no scheduled out in between
2022 * - thus the timestamp would be the same
2024 * But this is a bit hairy.
2026 * So instead, we have an explicit cgroup call to remain
2027 * within the time time source all along. We believe it
2028 * is cleaner and simpler to understand.
2030 if (is_cgroup_event(event))
2031 perf_cgroup_set_shadow_time(event, event->tstamp);
2033 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2036 #define MAX_INTERRUPTS (~0ULL)
2038 static void perf_log_throttle(struct perf_event *event, int enable);
2039 static void perf_log_itrace_start(struct perf_event *event);
2042 event_sched_in(struct perf_event *event,
2043 struct perf_cpu_context *cpuctx,
2044 struct perf_event_context *ctx)
2048 lockdep_assert_held(&ctx->lock);
2050 if (event->state <= PERF_EVENT_STATE_OFF)
2053 WRITE_ONCE(event->oncpu, smp_processor_id());
2055 * Order event::oncpu write to happen before the ACTIVE state is
2056 * visible. This allows perf_event_{stop,read}() to observe the correct
2057 * ->oncpu if it sees ACTIVE.
2060 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2063 * Unthrottle events, since we scheduled we might have missed several
2064 * ticks already, also for a heavily scheduling task there is little
2065 * guarantee it'll get a tick in a timely manner.
2067 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2068 perf_log_throttle(event, 1);
2069 event->hw.interrupts = 0;
2072 perf_pmu_disable(event->pmu);
2074 perf_set_shadow_time(event, ctx);
2076 perf_log_itrace_start(event);
2078 if (event->pmu->add(event, PERF_EF_START)) {
2079 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2085 if (!is_software_event(event))
2086 cpuctx->active_oncpu++;
2087 if (!ctx->nr_active++)
2088 perf_event_ctx_activate(ctx);
2089 if (event->attr.freq && event->attr.sample_freq)
2092 if (event->attr.exclusive)
2093 cpuctx->exclusive = 1;
2096 perf_pmu_enable(event->pmu);
2102 group_sched_in(struct perf_event *group_event,
2103 struct perf_cpu_context *cpuctx,
2104 struct perf_event_context *ctx)
2106 struct perf_event *event, *partial_group = NULL;
2107 struct pmu *pmu = ctx->pmu;
2109 if (group_event->state == PERF_EVENT_STATE_OFF)
2112 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2114 if (event_sched_in(group_event, cpuctx, ctx)) {
2115 pmu->cancel_txn(pmu);
2116 perf_mux_hrtimer_restart(cpuctx);
2121 * Schedule in siblings as one group (if any):
2123 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2124 if (event_sched_in(event, cpuctx, ctx)) {
2125 partial_group = event;
2130 if (!pmu->commit_txn(pmu))
2135 * Groups can be scheduled in as one unit only, so undo any
2136 * partial group before returning:
2137 * The events up to the failed event are scheduled out normally.
2139 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2140 if (event == partial_group)
2143 event_sched_out(event, cpuctx, ctx);
2145 event_sched_out(group_event, cpuctx, ctx);
2147 pmu->cancel_txn(pmu);
2149 perf_mux_hrtimer_restart(cpuctx);
2155 * Work out whether we can put this event group on the CPU now.
2157 static int group_can_go_on(struct perf_event *event,
2158 struct perf_cpu_context *cpuctx,
2162 * Groups consisting entirely of software events can always go on.
2164 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2167 * If an exclusive group is already on, no other hardware
2170 if (cpuctx->exclusive)
2173 * If this group is exclusive and there are already
2174 * events on the CPU, it can't go on.
2176 if (event->attr.exclusive && cpuctx->active_oncpu)
2179 * Otherwise, try to add it if all previous groups were able
2185 static void add_event_to_ctx(struct perf_event *event,
2186 struct perf_event_context *ctx)
2188 list_add_event(event, ctx);
2189 perf_group_attach(event);
2192 static void ctx_sched_out(struct perf_event_context *ctx,
2193 struct perf_cpu_context *cpuctx,
2194 enum event_type_t event_type);
2196 ctx_sched_in(struct perf_event_context *ctx,
2197 struct perf_cpu_context *cpuctx,
2198 enum event_type_t event_type,
2199 struct task_struct *task);
2201 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2202 struct perf_event_context *ctx,
2203 enum event_type_t event_type)
2205 if (!cpuctx->task_ctx)
2208 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2211 ctx_sched_out(ctx, cpuctx, event_type);
2214 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2215 struct perf_event_context *ctx,
2216 struct task_struct *task)
2218 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2220 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2221 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2223 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2227 * We want to maintain the following priority of scheduling:
2228 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2229 * - task pinned (EVENT_PINNED)
2230 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2231 * - task flexible (EVENT_FLEXIBLE).
2233 * In order to avoid unscheduling and scheduling back in everything every
2234 * time an event is added, only do it for the groups of equal priority and
2237 * This can be called after a batch operation on task events, in which case
2238 * event_type is a bit mask of the types of events involved. For CPU events,
2239 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2241 static void ctx_resched(struct perf_cpu_context *cpuctx,
2242 struct perf_event_context *task_ctx,
2243 enum event_type_t event_type)
2245 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2246 bool cpu_event = !!(event_type & EVENT_CPU);
2249 * If pinned groups are involved, flexible groups also need to be
2252 if (event_type & EVENT_PINNED)
2253 event_type |= EVENT_FLEXIBLE;
2255 perf_pmu_disable(cpuctx->ctx.pmu);
2257 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2260 * Decide which cpu ctx groups to schedule out based on the types
2261 * of events that caused rescheduling:
2262 * - EVENT_CPU: schedule out corresponding groups;
2263 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2264 * - otherwise, do nothing more.
2267 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2268 else if (ctx_event_type & EVENT_PINNED)
2269 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2271 perf_event_sched_in(cpuctx, task_ctx, current);
2272 perf_pmu_enable(cpuctx->ctx.pmu);
2276 * Cross CPU call to install and enable a performance event
2278 * Very similar to remote_function() + event_function() but cannot assume that
2279 * things like ctx->is_active and cpuctx->task_ctx are set.
2281 static int __perf_install_in_context(void *info)
2283 struct perf_event *event = info;
2284 struct perf_event_context *ctx = event->ctx;
2285 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2286 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2287 bool reprogram = true;
2290 raw_spin_lock(&cpuctx->ctx.lock);
2292 raw_spin_lock(&ctx->lock);
2295 reprogram = (ctx->task == current);
2298 * If the task is running, it must be running on this CPU,
2299 * otherwise we cannot reprogram things.
2301 * If its not running, we don't care, ctx->lock will
2302 * serialize against it becoming runnable.
2304 if (task_curr(ctx->task) && !reprogram) {
2309 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2310 } else if (task_ctx) {
2311 raw_spin_lock(&task_ctx->lock);
2315 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2316 add_event_to_ctx(event, ctx);
2317 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2319 add_event_to_ctx(event, ctx);
2323 perf_ctx_unlock(cpuctx, task_ctx);
2329 * Attach a performance event to a context.
2331 * Very similar to event_function_call, see comment there.
2334 perf_install_in_context(struct perf_event_context *ctx,
2335 struct perf_event *event,
2338 struct task_struct *task = READ_ONCE(ctx->task);
2340 lockdep_assert_held(&ctx->mutex);
2342 if (event->cpu != -1)
2346 * Ensures that if we can observe event->ctx, both the event and ctx
2347 * will be 'complete'. See perf_iterate_sb_cpu().
2349 smp_store_release(&event->ctx, ctx);
2352 cpu_function_call(cpu, __perf_install_in_context, event);
2357 * Should not happen, we validate the ctx is still alive before calling.
2359 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2363 * Installing events is tricky because we cannot rely on ctx->is_active
2364 * to be set in case this is the nr_events 0 -> 1 transition.
2366 * Instead we use task_curr(), which tells us if the task is running.
2367 * However, since we use task_curr() outside of rq::lock, we can race
2368 * against the actual state. This means the result can be wrong.
2370 * If we get a false positive, we retry, this is harmless.
2372 * If we get a false negative, things are complicated. If we are after
2373 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2374 * value must be correct. If we're before, it doesn't matter since
2375 * perf_event_context_sched_in() will program the counter.
2377 * However, this hinges on the remote context switch having observed
2378 * our task->perf_event_ctxp[] store, such that it will in fact take
2379 * ctx::lock in perf_event_context_sched_in().
2381 * We do this by task_function_call(), if the IPI fails to hit the task
2382 * we know any future context switch of task must see the
2383 * perf_event_ctpx[] store.
2387 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2388 * task_cpu() load, such that if the IPI then does not find the task
2389 * running, a future context switch of that task must observe the
2394 if (!task_function_call(task, __perf_install_in_context, event))
2397 raw_spin_lock_irq(&ctx->lock);
2399 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2401 * Cannot happen because we already checked above (which also
2402 * cannot happen), and we hold ctx->mutex, which serializes us
2403 * against perf_event_exit_task_context().
2405 raw_spin_unlock_irq(&ctx->lock);
2409 * If the task is not running, ctx->lock will avoid it becoming so,
2410 * thus we can safely install the event.
2412 if (task_curr(task)) {
2413 raw_spin_unlock_irq(&ctx->lock);
2416 add_event_to_ctx(event, ctx);
2417 raw_spin_unlock_irq(&ctx->lock);
2421 * Cross CPU call to enable a performance event
2423 static void __perf_event_enable(struct perf_event *event,
2424 struct perf_cpu_context *cpuctx,
2425 struct perf_event_context *ctx,
2428 struct perf_event *leader = event->group_leader;
2429 struct perf_event_context *task_ctx;
2431 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2432 event->state <= PERF_EVENT_STATE_ERROR)
2436 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2438 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2440 if (!ctx->is_active)
2443 if (!event_filter_match(event)) {
2444 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2449 * If the event is in a group and isn't the group leader,
2450 * then don't put it on unless the group is on.
2452 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2453 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2457 task_ctx = cpuctx->task_ctx;
2459 WARN_ON_ONCE(task_ctx != ctx);
2461 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2467 * If event->ctx is a cloned context, callers must make sure that
2468 * every task struct that event->ctx->task could possibly point to
2469 * remains valid. This condition is satisfied when called through
2470 * perf_event_for_each_child or perf_event_for_each as described
2471 * for perf_event_disable.
2473 static void _perf_event_enable(struct perf_event *event)
2475 struct perf_event_context *ctx = event->ctx;
2477 raw_spin_lock_irq(&ctx->lock);
2478 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2479 event->state < PERF_EVENT_STATE_ERROR) {
2480 raw_spin_unlock_irq(&ctx->lock);
2485 * If the event is in error state, clear that first.
2487 * That way, if we see the event in error state below, we know that it
2488 * has gone back into error state, as distinct from the task having
2489 * been scheduled away before the cross-call arrived.
2491 if (event->state == PERF_EVENT_STATE_ERROR)
2492 event->state = PERF_EVENT_STATE_OFF;
2493 raw_spin_unlock_irq(&ctx->lock);
2495 event_function_call(event, __perf_event_enable, NULL);
2499 * See perf_event_disable();
2501 void perf_event_enable(struct perf_event *event)
2503 struct perf_event_context *ctx;
2505 ctx = perf_event_ctx_lock(event);
2506 _perf_event_enable(event);
2507 perf_event_ctx_unlock(event, ctx);
2509 EXPORT_SYMBOL_GPL(perf_event_enable);
2511 struct stop_event_data {
2512 struct perf_event *event;
2513 unsigned int restart;
2516 static int __perf_event_stop(void *info)
2518 struct stop_event_data *sd = info;
2519 struct perf_event *event = sd->event;
2521 /* if it's already INACTIVE, do nothing */
2522 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2525 /* matches smp_wmb() in event_sched_in() */
2529 * There is a window with interrupts enabled before we get here,
2530 * so we need to check again lest we try to stop another CPU's event.
2532 if (READ_ONCE(event->oncpu) != smp_processor_id())
2535 event->pmu->stop(event, PERF_EF_UPDATE);
2538 * May race with the actual stop (through perf_pmu_output_stop()),
2539 * but it is only used for events with AUX ring buffer, and such
2540 * events will refuse to restart because of rb::aux_mmap_count==0,
2541 * see comments in perf_aux_output_begin().
2543 * Since this is happening on a event-local CPU, no trace is lost
2547 event->pmu->start(event, 0);
2552 static int perf_event_stop(struct perf_event *event, int restart)
2554 struct stop_event_data sd = {
2561 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2564 /* matches smp_wmb() in event_sched_in() */
2568 * We only want to restart ACTIVE events, so if the event goes
2569 * inactive here (event->oncpu==-1), there's nothing more to do;
2570 * fall through with ret==-ENXIO.
2572 ret = cpu_function_call(READ_ONCE(event->oncpu),
2573 __perf_event_stop, &sd);
2574 } while (ret == -EAGAIN);
2580 * In order to contain the amount of racy and tricky in the address filter
2581 * configuration management, it is a two part process:
2583 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2584 * we update the addresses of corresponding vmas in
2585 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2586 * (p2) when an event is scheduled in (pmu::add), it calls
2587 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2588 * if the generation has changed since the previous call.
2590 * If (p1) happens while the event is active, we restart it to force (p2).
2592 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2593 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2595 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2596 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2598 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2601 void perf_event_addr_filters_sync(struct perf_event *event)
2603 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2605 if (!has_addr_filter(event))
2608 raw_spin_lock(&ifh->lock);
2609 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2610 event->pmu->addr_filters_sync(event);
2611 event->hw.addr_filters_gen = event->addr_filters_gen;
2613 raw_spin_unlock(&ifh->lock);
2615 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2617 static int _perf_event_refresh(struct perf_event *event, int refresh)
2620 * not supported on inherited events
2622 if (event->attr.inherit || !is_sampling_event(event))
2625 atomic_add(refresh, &event->event_limit);
2626 _perf_event_enable(event);
2632 * See perf_event_disable()
2634 int perf_event_refresh(struct perf_event *event, int refresh)
2636 struct perf_event_context *ctx;
2639 ctx = perf_event_ctx_lock(event);
2640 ret = _perf_event_refresh(event, refresh);
2641 perf_event_ctx_unlock(event, ctx);
2645 EXPORT_SYMBOL_GPL(perf_event_refresh);
2647 static void ctx_sched_out(struct perf_event_context *ctx,
2648 struct perf_cpu_context *cpuctx,
2649 enum event_type_t event_type)
2651 int is_active = ctx->is_active;
2652 struct perf_event *event;
2654 lockdep_assert_held(&ctx->lock);
2656 if (likely(!ctx->nr_events)) {
2658 * See __perf_remove_from_context().
2660 WARN_ON_ONCE(ctx->is_active);
2662 WARN_ON_ONCE(cpuctx->task_ctx);
2666 ctx->is_active &= ~event_type;
2667 if (!(ctx->is_active & EVENT_ALL))
2671 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2672 if (!ctx->is_active)
2673 cpuctx->task_ctx = NULL;
2677 * Always update time if it was set; not only when it changes.
2678 * Otherwise we can 'forget' to update time for any but the last
2679 * context we sched out. For example:
2681 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2682 * ctx_sched_out(.event_type = EVENT_PINNED)
2684 * would only update time for the pinned events.
2686 if (is_active & EVENT_TIME) {
2687 /* update (and stop) ctx time */
2688 update_context_time(ctx);
2689 update_cgrp_time_from_cpuctx(cpuctx);
2692 is_active ^= ctx->is_active; /* changed bits */
2694 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2697 perf_pmu_disable(ctx->pmu);
2698 if (is_active & EVENT_PINNED) {
2699 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2700 group_sched_out(event, cpuctx, ctx);
2703 if (is_active & EVENT_FLEXIBLE) {
2704 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2705 group_sched_out(event, cpuctx, ctx);
2707 perf_pmu_enable(ctx->pmu);
2711 * Test whether two contexts are equivalent, i.e. whether they have both been
2712 * cloned from the same version of the same context.
2714 * Equivalence is measured using a generation number in the context that is
2715 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2716 * and list_del_event().
2718 static int context_equiv(struct perf_event_context *ctx1,
2719 struct perf_event_context *ctx2)
2721 lockdep_assert_held(&ctx1->lock);
2722 lockdep_assert_held(&ctx2->lock);
2724 /* Pinning disables the swap optimization */
2725 if (ctx1->pin_count || ctx2->pin_count)
2728 /* If ctx1 is the parent of ctx2 */
2729 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2732 /* If ctx2 is the parent of ctx1 */
2733 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2737 * If ctx1 and ctx2 have the same parent; we flatten the parent
2738 * hierarchy, see perf_event_init_context().
2740 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2741 ctx1->parent_gen == ctx2->parent_gen)
2748 static void __perf_event_sync_stat(struct perf_event *event,
2749 struct perf_event *next_event)
2753 if (!event->attr.inherit_stat)
2757 * Update the event value, we cannot use perf_event_read()
2758 * because we're in the middle of a context switch and have IRQs
2759 * disabled, which upsets smp_call_function_single(), however
2760 * we know the event must be on the current CPU, therefore we
2761 * don't need to use it.
2763 if (event->state == PERF_EVENT_STATE_ACTIVE)
2764 event->pmu->read(event);
2766 perf_event_update_time(event);
2769 * In order to keep per-task stats reliable we need to flip the event
2770 * values when we flip the contexts.
2772 value = local64_read(&next_event->count);
2773 value = local64_xchg(&event->count, value);
2774 local64_set(&next_event->count, value);
2776 swap(event->total_time_enabled, next_event->total_time_enabled);
2777 swap(event->total_time_running, next_event->total_time_running);
2780 * Since we swizzled the values, update the user visible data too.
2782 perf_event_update_userpage(event);
2783 perf_event_update_userpage(next_event);
2786 static void perf_event_sync_stat(struct perf_event_context *ctx,
2787 struct perf_event_context *next_ctx)
2789 struct perf_event *event, *next_event;
2794 update_context_time(ctx);
2796 event = list_first_entry(&ctx->event_list,
2797 struct perf_event, event_entry);
2799 next_event = list_first_entry(&next_ctx->event_list,
2800 struct perf_event, event_entry);
2802 while (&event->event_entry != &ctx->event_list &&
2803 &next_event->event_entry != &next_ctx->event_list) {
2805 __perf_event_sync_stat(event, next_event);
2807 event = list_next_entry(event, event_entry);
2808 next_event = list_next_entry(next_event, event_entry);
2812 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2813 struct task_struct *next)
2815 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2816 struct perf_event_context *next_ctx;
2817 struct perf_event_context *parent, *next_parent;
2818 struct perf_cpu_context *cpuctx;
2824 cpuctx = __get_cpu_context(ctx);
2825 if (!cpuctx->task_ctx)
2829 next_ctx = next->perf_event_ctxp[ctxn];
2833 parent = rcu_dereference(ctx->parent_ctx);
2834 next_parent = rcu_dereference(next_ctx->parent_ctx);
2836 /* If neither context have a parent context; they cannot be clones. */
2837 if (!parent && !next_parent)
2840 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2842 * Looks like the two contexts are clones, so we might be
2843 * able to optimize the context switch. We lock both
2844 * contexts and check that they are clones under the
2845 * lock (including re-checking that neither has been
2846 * uncloned in the meantime). It doesn't matter which
2847 * order we take the locks because no other cpu could
2848 * be trying to lock both of these tasks.
2850 raw_spin_lock(&ctx->lock);
2851 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2852 if (context_equiv(ctx, next_ctx)) {
2853 WRITE_ONCE(ctx->task, next);
2854 WRITE_ONCE(next_ctx->task, task);
2856 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2859 * RCU_INIT_POINTER here is safe because we've not
2860 * modified the ctx and the above modification of
2861 * ctx->task and ctx->task_ctx_data are immaterial
2862 * since those values are always verified under
2863 * ctx->lock which we're now holding.
2865 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2866 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2870 perf_event_sync_stat(ctx, next_ctx);
2872 raw_spin_unlock(&next_ctx->lock);
2873 raw_spin_unlock(&ctx->lock);
2879 raw_spin_lock(&ctx->lock);
2880 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2881 raw_spin_unlock(&ctx->lock);
2885 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2887 void perf_sched_cb_dec(struct pmu *pmu)
2889 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2891 this_cpu_dec(perf_sched_cb_usages);
2893 if (!--cpuctx->sched_cb_usage)
2894 list_del(&cpuctx->sched_cb_entry);
2898 void perf_sched_cb_inc(struct pmu *pmu)
2900 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2902 if (!cpuctx->sched_cb_usage++)
2903 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2905 this_cpu_inc(perf_sched_cb_usages);
2909 * This function provides the context switch callback to the lower code
2910 * layer. It is invoked ONLY when the context switch callback is enabled.
2912 * This callback is relevant even to per-cpu events; for example multi event
2913 * PEBS requires this to provide PID/TID information. This requires we flush
2914 * all queued PEBS records before we context switch to a new task.
2916 static void perf_pmu_sched_task(struct task_struct *prev,
2917 struct task_struct *next,
2920 struct perf_cpu_context *cpuctx;
2926 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2927 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2929 if (WARN_ON_ONCE(!pmu->sched_task))
2932 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2933 perf_pmu_disable(pmu);
2935 pmu->sched_task(cpuctx->task_ctx, sched_in);
2937 perf_pmu_enable(pmu);
2938 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2942 static void perf_event_switch(struct task_struct *task,
2943 struct task_struct *next_prev, bool sched_in);
2945 #define for_each_task_context_nr(ctxn) \
2946 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2949 * Called from scheduler to remove the events of the current task,
2950 * with interrupts disabled.
2952 * We stop each event and update the event value in event->count.
2954 * This does not protect us against NMI, but disable()
2955 * sets the disabled bit in the control field of event _before_
2956 * accessing the event control register. If a NMI hits, then it will
2957 * not restart the event.
2959 void __perf_event_task_sched_out(struct task_struct *task,
2960 struct task_struct *next)
2964 if (__this_cpu_read(perf_sched_cb_usages))
2965 perf_pmu_sched_task(task, next, false);
2967 if (atomic_read(&nr_switch_events))
2968 perf_event_switch(task, next, false);
2970 for_each_task_context_nr(ctxn)
2971 perf_event_context_sched_out(task, ctxn, next);
2974 * if cgroup events exist on this CPU, then we need
2975 * to check if we have to switch out PMU state.
2976 * cgroup event are system-wide mode only
2978 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2979 perf_cgroup_sched_out(task, next);
2983 * Called with IRQs disabled
2985 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2986 enum event_type_t event_type)
2988 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2992 ctx_pinned_sched_in(struct perf_event_context *ctx,
2993 struct perf_cpu_context *cpuctx)
2995 struct perf_event *event;
2997 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2998 if (event->state <= PERF_EVENT_STATE_OFF)
3000 if (!event_filter_match(event))
3003 if (group_can_go_on(event, cpuctx, 1))
3004 group_sched_in(event, cpuctx, ctx);
3007 * If this pinned group hasn't been scheduled,
3008 * put it in error state.
3010 if (event->state == PERF_EVENT_STATE_INACTIVE)
3011 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3016 ctx_flexible_sched_in(struct perf_event_context *ctx,
3017 struct perf_cpu_context *cpuctx)
3019 struct perf_event *event;
3022 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3023 /* Ignore events in OFF or ERROR state */
3024 if (event->state <= PERF_EVENT_STATE_OFF)
3027 * Listen to the 'cpu' scheduling filter constraint
3030 if (!event_filter_match(event))
3033 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3034 if (group_sched_in(event, cpuctx, ctx))
3041 ctx_sched_in(struct perf_event_context *ctx,
3042 struct perf_cpu_context *cpuctx,
3043 enum event_type_t event_type,
3044 struct task_struct *task)
3046 int is_active = ctx->is_active;
3049 lockdep_assert_held(&ctx->lock);
3051 if (likely(!ctx->nr_events))
3054 ctx->is_active |= (event_type | EVENT_TIME);
3057 cpuctx->task_ctx = ctx;
3059 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3062 is_active ^= ctx->is_active; /* changed bits */
3064 if (is_active & EVENT_TIME) {
3065 /* start ctx time */
3067 ctx->timestamp = now;
3068 perf_cgroup_set_timestamp(task, ctx);
3072 * First go through the list and put on any pinned groups
3073 * in order to give them the best chance of going on.
3075 if (is_active & EVENT_PINNED)
3076 ctx_pinned_sched_in(ctx, cpuctx);
3078 /* Then walk through the lower prio flexible groups */
3079 if (is_active & EVENT_FLEXIBLE)
3080 ctx_flexible_sched_in(ctx, cpuctx);
3083 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3084 enum event_type_t event_type,
3085 struct task_struct *task)
3087 struct perf_event_context *ctx = &cpuctx->ctx;
3089 ctx_sched_in(ctx, cpuctx, event_type, task);
3092 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3093 struct task_struct *task)
3095 struct perf_cpu_context *cpuctx;
3097 cpuctx = __get_cpu_context(ctx);
3098 if (cpuctx->task_ctx == ctx)
3101 perf_ctx_lock(cpuctx, ctx);
3103 * We must check ctx->nr_events while holding ctx->lock, such
3104 * that we serialize against perf_install_in_context().
3106 if (!ctx->nr_events)
3109 perf_pmu_disable(ctx->pmu);
3111 * We want to keep the following priority order:
3112 * cpu pinned (that don't need to move), task pinned,
3113 * cpu flexible, task flexible.
3115 * However, if task's ctx is not carrying any pinned
3116 * events, no need to flip the cpuctx's events around.
3118 if (!list_empty(&ctx->pinned_groups))
3119 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3120 perf_event_sched_in(cpuctx, ctx, task);
3121 perf_pmu_enable(ctx->pmu);
3124 perf_ctx_unlock(cpuctx, ctx);
3128 * Called from scheduler to add the events of the current task
3129 * with interrupts disabled.
3131 * We restore the event value and then enable it.
3133 * This does not protect us against NMI, but enable()
3134 * sets the enabled bit in the control field of event _before_
3135 * accessing the event control register. If a NMI hits, then it will
3136 * keep the event running.
3138 void __perf_event_task_sched_in(struct task_struct *prev,
3139 struct task_struct *task)
3141 struct perf_event_context *ctx;
3145 * If cgroup events exist on this CPU, then we need to check if we have
3146 * to switch in PMU state; cgroup event are system-wide mode only.
3148 * Since cgroup events are CPU events, we must schedule these in before
3149 * we schedule in the task events.
3151 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3152 perf_cgroup_sched_in(prev, task);
3154 for_each_task_context_nr(ctxn) {
3155 ctx = task->perf_event_ctxp[ctxn];
3159 perf_event_context_sched_in(ctx, task);
3162 if (atomic_read(&nr_switch_events))
3163 perf_event_switch(task, prev, true);
3165 if (__this_cpu_read(perf_sched_cb_usages))
3166 perf_pmu_sched_task(prev, task, true);
3169 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3171 u64 frequency = event->attr.sample_freq;
3172 u64 sec = NSEC_PER_SEC;
3173 u64 divisor, dividend;
3175 int count_fls, nsec_fls, frequency_fls, sec_fls;
3177 count_fls = fls64(count);
3178 nsec_fls = fls64(nsec);
3179 frequency_fls = fls64(frequency);
3183 * We got @count in @nsec, with a target of sample_freq HZ
3184 * the target period becomes:
3187 * period = -------------------
3188 * @nsec * sample_freq
3193 * Reduce accuracy by one bit such that @a and @b converge
3194 * to a similar magnitude.
3196 #define REDUCE_FLS(a, b) \
3198 if (a##_fls > b##_fls) { \
3208 * Reduce accuracy until either term fits in a u64, then proceed with
3209 * the other, so that finally we can do a u64/u64 division.
3211 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3212 REDUCE_FLS(nsec, frequency);
3213 REDUCE_FLS(sec, count);
3216 if (count_fls + sec_fls > 64) {
3217 divisor = nsec * frequency;
3219 while (count_fls + sec_fls > 64) {
3220 REDUCE_FLS(count, sec);
3224 dividend = count * sec;
3226 dividend = count * sec;
3228 while (nsec_fls + frequency_fls > 64) {
3229 REDUCE_FLS(nsec, frequency);
3233 divisor = nsec * frequency;
3239 return div64_u64(dividend, divisor);
3242 static DEFINE_PER_CPU(int, perf_throttled_count);
3243 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3245 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3247 struct hw_perf_event *hwc = &event->hw;
3248 s64 period, sample_period;
3251 period = perf_calculate_period(event, nsec, count);
3253 delta = (s64)(period - hwc->sample_period);
3254 delta = (delta + 7) / 8; /* low pass filter */
3256 sample_period = hwc->sample_period + delta;
3261 hwc->sample_period = sample_period;
3263 if (local64_read(&hwc->period_left) > 8*sample_period) {
3265 event->pmu->stop(event, PERF_EF_UPDATE);
3267 local64_set(&hwc->period_left, 0);
3270 event->pmu->start(event, PERF_EF_RELOAD);
3275 * combine freq adjustment with unthrottling to avoid two passes over the
3276 * events. At the same time, make sure, having freq events does not change
3277 * the rate of unthrottling as that would introduce bias.
3279 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3282 struct perf_event *event;
3283 struct hw_perf_event *hwc;
3284 u64 now, period = TICK_NSEC;
3288 * only need to iterate over all events iff:
3289 * - context have events in frequency mode (needs freq adjust)
3290 * - there are events to unthrottle on this cpu
3292 if (!(ctx->nr_freq || needs_unthr))
3295 raw_spin_lock(&ctx->lock);
3296 perf_pmu_disable(ctx->pmu);
3298 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3299 if (event->state != PERF_EVENT_STATE_ACTIVE)
3302 if (!event_filter_match(event))
3305 perf_pmu_disable(event->pmu);
3309 if (hwc->interrupts == MAX_INTERRUPTS) {
3310 hwc->interrupts = 0;
3311 perf_log_throttle(event, 1);
3312 event->pmu->start(event, 0);
3315 if (!event->attr.freq || !event->attr.sample_freq)
3319 * stop the event and update event->count
3321 event->pmu->stop(event, PERF_EF_UPDATE);
3323 now = local64_read(&event->count);
3324 delta = now - hwc->freq_count_stamp;
3325 hwc->freq_count_stamp = now;
3329 * reload only if value has changed
3330 * we have stopped the event so tell that
3331 * to perf_adjust_period() to avoid stopping it
3335 perf_adjust_period(event, period, delta, false);
3337 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3339 perf_pmu_enable(event->pmu);
3342 perf_pmu_enable(ctx->pmu);
3343 raw_spin_unlock(&ctx->lock);
3347 * Round-robin a context's events:
3349 static void rotate_ctx(struct perf_event_context *ctx)
3352 * Rotate the first entry last of non-pinned groups. Rotation might be
3353 * disabled by the inheritance code.
3355 if (!ctx->rotate_disable)
3356 list_rotate_left(&ctx->flexible_groups);
3359 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3361 struct perf_event_context *ctx = NULL;
3364 if (cpuctx->ctx.nr_events) {
3365 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3369 ctx = cpuctx->task_ctx;
3370 if (ctx && ctx->nr_events) {
3371 if (ctx->nr_events != ctx->nr_active)
3378 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3379 perf_pmu_disable(cpuctx->ctx.pmu);
3381 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3383 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3385 rotate_ctx(&cpuctx->ctx);
3389 perf_event_sched_in(cpuctx, ctx, current);
3391 perf_pmu_enable(cpuctx->ctx.pmu);
3392 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3398 void perf_event_task_tick(void)
3400 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3401 struct perf_event_context *ctx, *tmp;
3404 lockdep_assert_irqs_disabled();
3406 __this_cpu_inc(perf_throttled_seq);
3407 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3408 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3410 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3411 perf_adjust_freq_unthr_context(ctx, throttled);
3414 static int event_enable_on_exec(struct perf_event *event,
3415 struct perf_event_context *ctx)
3417 if (!event->attr.enable_on_exec)
3420 event->attr.enable_on_exec = 0;
3421 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3424 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3430 * Enable all of a task's events that have been marked enable-on-exec.
3431 * This expects task == current.
3433 static void perf_event_enable_on_exec(int ctxn)
3435 struct perf_event_context *ctx, *clone_ctx = NULL;
3436 enum event_type_t event_type = 0;
3437 struct perf_cpu_context *cpuctx;
3438 struct perf_event *event;
3439 unsigned long flags;
3442 local_irq_save(flags);
3443 ctx = current->perf_event_ctxp[ctxn];
3444 if (!ctx || !ctx->nr_events)
3447 cpuctx = __get_cpu_context(ctx);
3448 perf_ctx_lock(cpuctx, ctx);
3449 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3450 list_for_each_entry(event, &ctx->event_list, event_entry) {
3451 enabled |= event_enable_on_exec(event, ctx);
3452 event_type |= get_event_type(event);
3456 * Unclone and reschedule this context if we enabled any event.
3459 clone_ctx = unclone_ctx(ctx);
3460 ctx_resched(cpuctx, ctx, event_type);
3462 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3464 perf_ctx_unlock(cpuctx, ctx);
3467 local_irq_restore(flags);
3473 struct perf_read_data {
3474 struct perf_event *event;
3479 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3481 u16 local_pkg, event_pkg;
3483 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3484 int local_cpu = smp_processor_id();
3486 event_pkg = topology_physical_package_id(event_cpu);
3487 local_pkg = topology_physical_package_id(local_cpu);
3489 if (event_pkg == local_pkg)
3497 * Cross CPU call to read the hardware event
3499 static void __perf_event_read(void *info)
3501 struct perf_read_data *data = info;
3502 struct perf_event *sub, *event = data->event;
3503 struct perf_event_context *ctx = event->ctx;
3504 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3505 struct pmu *pmu = event->pmu;
3508 * If this is a task context, we need to check whether it is
3509 * the current task context of this cpu. If not it has been
3510 * scheduled out before the smp call arrived. In that case
3511 * event->count would have been updated to a recent sample
3512 * when the event was scheduled out.
3514 if (ctx->task && cpuctx->task_ctx != ctx)
3517 raw_spin_lock(&ctx->lock);
3518 if (ctx->is_active & EVENT_TIME) {
3519 update_context_time(ctx);
3520 update_cgrp_time_from_event(event);
3523 perf_event_update_time(event);
3525 perf_event_update_sibling_time(event);
3527 if (event->state != PERF_EVENT_STATE_ACTIVE)
3536 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3540 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3541 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3543 * Use sibling's PMU rather than @event's since
3544 * sibling could be on different (eg: software) PMU.
3546 sub->pmu->read(sub);
3550 data->ret = pmu->commit_txn(pmu);
3553 raw_spin_unlock(&ctx->lock);
3556 static inline u64 perf_event_count(struct perf_event *event)
3558 return local64_read(&event->count) + atomic64_read(&event->child_count);
3562 * NMI-safe method to read a local event, that is an event that
3564 * - either for the current task, or for this CPU
3565 * - does not have inherit set, for inherited task events
3566 * will not be local and we cannot read them atomically
3567 * - must not have a pmu::count method
3569 int perf_event_read_local(struct perf_event *event, u64 *value,
3570 u64 *enabled, u64 *running)
3572 unsigned long flags;
3576 * Disabling interrupts avoids all counter scheduling (context
3577 * switches, timer based rotation and IPIs).
3579 local_irq_save(flags);
3582 * It must not be an event with inherit set, we cannot read
3583 * all child counters from atomic context.
3585 if (event->attr.inherit) {
3590 /* If this is a per-task event, it must be for current */
3591 if ((event->attach_state & PERF_ATTACH_TASK) &&
3592 event->hw.target != current) {
3597 /* If this is a per-CPU event, it must be for this CPU */
3598 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3599 event->cpu != smp_processor_id()) {
3605 * If the event is currently on this CPU, its either a per-task event,
3606 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3609 if (event->oncpu == smp_processor_id())
3610 event->pmu->read(event);
3612 *value = local64_read(&event->count);
3613 if (enabled || running) {
3614 u64 now = event->shadow_ctx_time + perf_clock();
3615 u64 __enabled, __running;
3617 __perf_update_times(event, now, &__enabled, &__running);
3619 *enabled = __enabled;
3621 *running = __running;
3624 local_irq_restore(flags);
3629 static int perf_event_read(struct perf_event *event, bool group)
3631 enum perf_event_state state = READ_ONCE(event->state);
3632 int event_cpu, ret = 0;
3635 * If event is enabled and currently active on a CPU, update the
3636 * value in the event structure:
3639 if (state == PERF_EVENT_STATE_ACTIVE) {
3640 struct perf_read_data data;
3643 * Orders the ->state and ->oncpu loads such that if we see
3644 * ACTIVE we must also see the right ->oncpu.
3646 * Matches the smp_wmb() from event_sched_in().
3650 event_cpu = READ_ONCE(event->oncpu);
3651 if ((unsigned)event_cpu >= nr_cpu_ids)
3654 data = (struct perf_read_data){
3661 event_cpu = __perf_event_read_cpu(event, event_cpu);
3664 * Purposely ignore the smp_call_function_single() return
3667 * If event_cpu isn't a valid CPU it means the event got
3668 * scheduled out and that will have updated the event count.
3670 * Therefore, either way, we'll have an up-to-date event count
3673 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3677 } else if (state == PERF_EVENT_STATE_INACTIVE) {
3678 struct perf_event_context *ctx = event->ctx;
3679 unsigned long flags;
3681 raw_spin_lock_irqsave(&ctx->lock, flags);
3682 state = event->state;
3683 if (state != PERF_EVENT_STATE_INACTIVE) {
3684 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3689 * May read while context is not active (e.g., thread is
3690 * blocked), in that case we cannot update context time
3692 if (ctx->is_active & EVENT_TIME) {
3693 update_context_time(ctx);
3694 update_cgrp_time_from_event(event);
3697 perf_event_update_time(event);
3699 perf_event_update_sibling_time(event);
3700 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3707 * Initialize the perf_event context in a task_struct:
3709 static void __perf_event_init_context(struct perf_event_context *ctx)
3711 raw_spin_lock_init(&ctx->lock);
3712 mutex_init(&ctx->mutex);
3713 INIT_LIST_HEAD(&ctx->active_ctx_list);
3714 INIT_LIST_HEAD(&ctx->pinned_groups);
3715 INIT_LIST_HEAD(&ctx->flexible_groups);
3716 INIT_LIST_HEAD(&ctx->event_list);
3717 atomic_set(&ctx->refcount, 1);
3720 static struct perf_event_context *
3721 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3723 struct perf_event_context *ctx;
3725 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3729 __perf_event_init_context(ctx);
3732 get_task_struct(task);
3739 static struct task_struct *
3740 find_lively_task_by_vpid(pid_t vpid)
3742 struct task_struct *task;
3748 task = find_task_by_vpid(vpid);
3750 get_task_struct(task);
3754 return ERR_PTR(-ESRCH);
3760 * Returns a matching context with refcount and pincount.
3762 static struct perf_event_context *
3763 find_get_context(struct pmu *pmu, struct task_struct *task,
3764 struct perf_event *event)
3766 struct perf_event_context *ctx, *clone_ctx = NULL;
3767 struct perf_cpu_context *cpuctx;
3768 void *task_ctx_data = NULL;
3769 unsigned long flags;
3771 int cpu = event->cpu;
3774 /* Must be root to operate on a CPU event: */
3775 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3776 return ERR_PTR(-EACCES);
3778 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3787 ctxn = pmu->task_ctx_nr;
3791 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3792 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3793 if (!task_ctx_data) {
3800 ctx = perf_lock_task_context(task, ctxn, &flags);
3802 clone_ctx = unclone_ctx(ctx);
3805 if (task_ctx_data && !ctx->task_ctx_data) {
3806 ctx->task_ctx_data = task_ctx_data;
3807 task_ctx_data = NULL;
3809 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3814 ctx = alloc_perf_context(pmu, task);
3819 if (task_ctx_data) {
3820 ctx->task_ctx_data = task_ctx_data;
3821 task_ctx_data = NULL;
3825 mutex_lock(&task->perf_event_mutex);
3827 * If it has already passed perf_event_exit_task().
3828 * we must see PF_EXITING, it takes this mutex too.
3830 if (task->flags & PF_EXITING)
3832 else if (task->perf_event_ctxp[ctxn])
3837 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3839 mutex_unlock(&task->perf_event_mutex);
3841 if (unlikely(err)) {
3850 kfree(task_ctx_data);
3854 kfree(task_ctx_data);
3855 return ERR_PTR(err);
3858 static void perf_event_free_filter(struct perf_event *event);
3859 static void perf_event_free_bpf_prog(struct perf_event *event);
3861 static void free_event_rcu(struct rcu_head *head)
3863 struct perf_event *event;
3865 event = container_of(head, struct perf_event, rcu_head);
3867 put_pid_ns(event->ns);
3868 perf_event_free_filter(event);
3872 static void ring_buffer_attach(struct perf_event *event,
3873 struct ring_buffer *rb);
3875 static void detach_sb_event(struct perf_event *event)
3877 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3879 raw_spin_lock(&pel->lock);
3880 list_del_rcu(&event->sb_list);
3881 raw_spin_unlock(&pel->lock);
3884 static bool is_sb_event(struct perf_event *event)
3886 struct perf_event_attr *attr = &event->attr;
3891 if (event->attach_state & PERF_ATTACH_TASK)
3894 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3895 attr->comm || attr->comm_exec ||
3897 attr->context_switch)
3902 static void unaccount_pmu_sb_event(struct perf_event *event)
3904 if (is_sb_event(event))
3905 detach_sb_event(event);
3908 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3913 if (is_cgroup_event(event))
3914 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3917 #ifdef CONFIG_NO_HZ_FULL
3918 static DEFINE_SPINLOCK(nr_freq_lock);
3921 static void unaccount_freq_event_nohz(void)
3923 #ifdef CONFIG_NO_HZ_FULL
3924 spin_lock(&nr_freq_lock);
3925 if (atomic_dec_and_test(&nr_freq_events))
3926 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3927 spin_unlock(&nr_freq_lock);
3931 static void unaccount_freq_event(void)
3933 if (tick_nohz_full_enabled())
3934 unaccount_freq_event_nohz();
3936 atomic_dec(&nr_freq_events);
3939 static void unaccount_event(struct perf_event *event)
3946 if (event->attach_state & PERF_ATTACH_TASK)
3948 if (event->attr.mmap || event->attr.mmap_data)
3949 atomic_dec(&nr_mmap_events);
3950 if (event->attr.comm)
3951 atomic_dec(&nr_comm_events);
3952 if (event->attr.namespaces)
3953 atomic_dec(&nr_namespaces_events);
3954 if (event->attr.task)
3955 atomic_dec(&nr_task_events);
3956 if (event->attr.freq)
3957 unaccount_freq_event();
3958 if (event->attr.context_switch) {
3960 atomic_dec(&nr_switch_events);
3962 if (is_cgroup_event(event))
3964 if (has_branch_stack(event))
3968 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3969 schedule_delayed_work(&perf_sched_work, HZ);
3972 unaccount_event_cpu(event, event->cpu);
3974 unaccount_pmu_sb_event(event);
3977 static void perf_sched_delayed(struct work_struct *work)
3979 mutex_lock(&perf_sched_mutex);
3980 if (atomic_dec_and_test(&perf_sched_count))
3981 static_branch_disable(&perf_sched_events);
3982 mutex_unlock(&perf_sched_mutex);
3986 * The following implement mutual exclusion of events on "exclusive" pmus
3987 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3988 * at a time, so we disallow creating events that might conflict, namely:
3990 * 1) cpu-wide events in the presence of per-task events,
3991 * 2) per-task events in the presence of cpu-wide events,
3992 * 3) two matching events on the same context.
3994 * The former two cases are handled in the allocation path (perf_event_alloc(),
3995 * _free_event()), the latter -- before the first perf_install_in_context().
3997 static int exclusive_event_init(struct perf_event *event)
3999 struct pmu *pmu = event->pmu;
4001 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4005 * Prevent co-existence of per-task and cpu-wide events on the
4006 * same exclusive pmu.
4008 * Negative pmu::exclusive_cnt means there are cpu-wide
4009 * events on this "exclusive" pmu, positive means there are
4012 * Since this is called in perf_event_alloc() path, event::ctx
4013 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4014 * to mean "per-task event", because unlike other attach states it
4015 * never gets cleared.
4017 if (event->attach_state & PERF_ATTACH_TASK) {
4018 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4021 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4028 static void exclusive_event_destroy(struct perf_event *event)
4030 struct pmu *pmu = event->pmu;
4032 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4035 /* see comment in exclusive_event_init() */
4036 if (event->attach_state & PERF_ATTACH_TASK)
4037 atomic_dec(&pmu->exclusive_cnt);
4039 atomic_inc(&pmu->exclusive_cnt);
4042 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4044 if ((e1->pmu == e2->pmu) &&
4045 (e1->cpu == e2->cpu ||
4052 /* Called under the same ctx::mutex as perf_install_in_context() */
4053 static bool exclusive_event_installable(struct perf_event *event,
4054 struct perf_event_context *ctx)
4056 struct perf_event *iter_event;
4057 struct pmu *pmu = event->pmu;
4059 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4062 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4063 if (exclusive_event_match(iter_event, event))
4070 static void perf_addr_filters_splice(struct perf_event *event,
4071 struct list_head *head);
4073 static void _free_event(struct perf_event *event)
4075 irq_work_sync(&event->pending);
4077 unaccount_event(event);
4081 * Can happen when we close an event with re-directed output.
4083 * Since we have a 0 refcount, perf_mmap_close() will skip
4084 * over us; possibly making our ring_buffer_put() the last.
4086 mutex_lock(&event->mmap_mutex);
4087 ring_buffer_attach(event, NULL);
4088 mutex_unlock(&event->mmap_mutex);
4091 if (is_cgroup_event(event))
4092 perf_detach_cgroup(event);
4094 if (!event->parent) {
4095 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4096 put_callchain_buffers();
4099 perf_event_free_bpf_prog(event);
4100 perf_addr_filters_splice(event, NULL);
4101 kfree(event->addr_filters_offs);
4104 event->destroy(event);
4107 put_ctx(event->ctx);
4109 exclusive_event_destroy(event);
4110 module_put(event->pmu->module);
4112 call_rcu(&event->rcu_head, free_event_rcu);
4116 * Used to free events which have a known refcount of 1, such as in error paths
4117 * where the event isn't exposed yet and inherited events.
4119 static void free_event(struct perf_event *event)
4121 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4122 "unexpected event refcount: %ld; ptr=%p\n",
4123 atomic_long_read(&event->refcount), event)) {
4124 /* leak to avoid use-after-free */
4132 * Remove user event from the owner task.
4134 static void perf_remove_from_owner(struct perf_event *event)
4136 struct task_struct *owner;
4140 * Matches the smp_store_release() in perf_event_exit_task(). If we
4141 * observe !owner it means the list deletion is complete and we can
4142 * indeed free this event, otherwise we need to serialize on
4143 * owner->perf_event_mutex.
4145 owner = READ_ONCE(event->owner);
4148 * Since delayed_put_task_struct() also drops the last
4149 * task reference we can safely take a new reference
4150 * while holding the rcu_read_lock().
4152 get_task_struct(owner);
4158 * If we're here through perf_event_exit_task() we're already
4159 * holding ctx->mutex which would be an inversion wrt. the
4160 * normal lock order.
4162 * However we can safely take this lock because its the child
4165 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4168 * We have to re-check the event->owner field, if it is cleared
4169 * we raced with perf_event_exit_task(), acquiring the mutex
4170 * ensured they're done, and we can proceed with freeing the
4174 list_del_init(&event->owner_entry);
4175 smp_store_release(&event->owner, NULL);
4177 mutex_unlock(&owner->perf_event_mutex);
4178 put_task_struct(owner);
4182 static void put_event(struct perf_event *event)
4184 if (!atomic_long_dec_and_test(&event->refcount))
4191 * Kill an event dead; while event:refcount will preserve the event
4192 * object, it will not preserve its functionality. Once the last 'user'
4193 * gives up the object, we'll destroy the thing.
4195 int perf_event_release_kernel(struct perf_event *event)
4197 struct perf_event_context *ctx = event->ctx;
4198 struct perf_event *child, *tmp;
4201 * If we got here through err_file: fput(event_file); we will not have
4202 * attached to a context yet.
4205 WARN_ON_ONCE(event->attach_state &
4206 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4210 if (!is_kernel_event(event))
4211 perf_remove_from_owner(event);
4213 ctx = perf_event_ctx_lock(event);
4214 WARN_ON_ONCE(ctx->parent_ctx);
4215 perf_remove_from_context(event, DETACH_GROUP);
4217 raw_spin_lock_irq(&ctx->lock);
4219 * Mark this event as STATE_DEAD, there is no external reference to it
4222 * Anybody acquiring event->child_mutex after the below loop _must_
4223 * also see this, most importantly inherit_event() which will avoid
4224 * placing more children on the list.
4226 * Thus this guarantees that we will in fact observe and kill _ALL_
4229 event->state = PERF_EVENT_STATE_DEAD;
4230 raw_spin_unlock_irq(&ctx->lock);
4232 perf_event_ctx_unlock(event, ctx);
4235 mutex_lock(&event->child_mutex);
4236 list_for_each_entry(child, &event->child_list, child_list) {
4239 * Cannot change, child events are not migrated, see the
4240 * comment with perf_event_ctx_lock_nested().
4242 ctx = READ_ONCE(child->ctx);
4244 * Since child_mutex nests inside ctx::mutex, we must jump
4245 * through hoops. We start by grabbing a reference on the ctx.
4247 * Since the event cannot get freed while we hold the
4248 * child_mutex, the context must also exist and have a !0
4254 * Now that we have a ctx ref, we can drop child_mutex, and
4255 * acquire ctx::mutex without fear of it going away. Then we
4256 * can re-acquire child_mutex.
4258 mutex_unlock(&event->child_mutex);
4259 mutex_lock(&ctx->mutex);
4260 mutex_lock(&event->child_mutex);
4263 * Now that we hold ctx::mutex and child_mutex, revalidate our
4264 * state, if child is still the first entry, it didn't get freed
4265 * and we can continue doing so.
4267 tmp = list_first_entry_or_null(&event->child_list,
4268 struct perf_event, child_list);
4270 perf_remove_from_context(child, DETACH_GROUP);
4271 list_del(&child->child_list);
4274 * This matches the refcount bump in inherit_event();
4275 * this can't be the last reference.
4280 mutex_unlock(&event->child_mutex);
4281 mutex_unlock(&ctx->mutex);
4285 mutex_unlock(&event->child_mutex);
4288 put_event(event); /* Must be the 'last' reference */
4291 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4294 * Called when the last reference to the file is gone.
4296 static int perf_release(struct inode *inode, struct file *file)
4298 perf_event_release_kernel(file->private_data);
4302 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4304 struct perf_event *child;
4310 mutex_lock(&event->child_mutex);
4312 (void)perf_event_read(event, false);
4313 total += perf_event_count(event);
4315 *enabled += event->total_time_enabled +
4316 atomic64_read(&event->child_total_time_enabled);
4317 *running += event->total_time_running +
4318 atomic64_read(&event->child_total_time_running);
4320 list_for_each_entry(child, &event->child_list, child_list) {
4321 (void)perf_event_read(child, false);
4322 total += perf_event_count(child);
4323 *enabled += child->total_time_enabled;
4324 *running += child->total_time_running;
4326 mutex_unlock(&event->child_mutex);
4331 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4333 struct perf_event_context *ctx;
4336 ctx = perf_event_ctx_lock(event);
4337 count = __perf_event_read_value(event, enabled, running);
4338 perf_event_ctx_unlock(event, ctx);
4342 EXPORT_SYMBOL_GPL(perf_event_read_value);
4344 static int __perf_read_group_add(struct perf_event *leader,
4345 u64 read_format, u64 *values)
4347 struct perf_event_context *ctx = leader->ctx;
4348 struct perf_event *sub;
4349 unsigned long flags;
4350 int n = 1; /* skip @nr */
4353 ret = perf_event_read(leader, true);
4357 raw_spin_lock_irqsave(&ctx->lock, flags);
4360 * Since we co-schedule groups, {enabled,running} times of siblings
4361 * will be identical to those of the leader, so we only publish one
4364 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4365 values[n++] += leader->total_time_enabled +
4366 atomic64_read(&leader->child_total_time_enabled);
4369 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4370 values[n++] += leader->total_time_running +
4371 atomic64_read(&leader->child_total_time_running);
4375 * Write {count,id} tuples for every sibling.
4377 values[n++] += perf_event_count(leader);
4378 if (read_format & PERF_FORMAT_ID)
4379 values[n++] = primary_event_id(leader);
4381 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4382 values[n++] += perf_event_count(sub);
4383 if (read_format & PERF_FORMAT_ID)
4384 values[n++] = primary_event_id(sub);
4387 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4391 static int perf_read_group(struct perf_event *event,
4392 u64 read_format, char __user *buf)
4394 struct perf_event *leader = event->group_leader, *child;
4395 struct perf_event_context *ctx = leader->ctx;
4399 lockdep_assert_held(&ctx->mutex);
4401 values = kzalloc(event->read_size, GFP_KERNEL);
4405 values[0] = 1 + leader->nr_siblings;
4408 * By locking the child_mutex of the leader we effectively
4409 * lock the child list of all siblings.. XXX explain how.
4411 mutex_lock(&leader->child_mutex);
4413 ret = __perf_read_group_add(leader, read_format, values);
4417 list_for_each_entry(child, &leader->child_list, child_list) {
4418 ret = __perf_read_group_add(child, read_format, values);
4423 mutex_unlock(&leader->child_mutex);
4425 ret = event->read_size;
4426 if (copy_to_user(buf, values, event->read_size))
4431 mutex_unlock(&leader->child_mutex);
4437 static int perf_read_one(struct perf_event *event,
4438 u64 read_format, char __user *buf)
4440 u64 enabled, running;
4444 values[n++] = __perf_event_read_value(event, &enabled, &running);
4445 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4446 values[n++] = enabled;
4447 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4448 values[n++] = running;
4449 if (read_format & PERF_FORMAT_ID)
4450 values[n++] = primary_event_id(event);
4452 if (copy_to_user(buf, values, n * sizeof(u64)))
4455 return n * sizeof(u64);
4458 static bool is_event_hup(struct perf_event *event)
4462 if (event->state > PERF_EVENT_STATE_EXIT)
4465 mutex_lock(&event->child_mutex);
4466 no_children = list_empty(&event->child_list);
4467 mutex_unlock(&event->child_mutex);
4472 * Read the performance event - simple non blocking version for now
4475 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4477 u64 read_format = event->attr.read_format;
4481 * Return end-of-file for a read on a event that is in
4482 * error state (i.e. because it was pinned but it couldn't be
4483 * scheduled on to the CPU at some point).
4485 if (event->state == PERF_EVENT_STATE_ERROR)
4488 if (count < event->read_size)
4491 WARN_ON_ONCE(event->ctx->parent_ctx);
4492 if (read_format & PERF_FORMAT_GROUP)
4493 ret = perf_read_group(event, read_format, buf);
4495 ret = perf_read_one(event, read_format, buf);
4501 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4503 struct perf_event *event = file->private_data;
4504 struct perf_event_context *ctx;
4507 ctx = perf_event_ctx_lock(event);
4508 ret = __perf_read(event, buf, count);
4509 perf_event_ctx_unlock(event, ctx);
4514 static unsigned int perf_poll(struct file *file, poll_table *wait)
4516 struct perf_event *event = file->private_data;
4517 struct ring_buffer *rb;
4518 unsigned int events = POLLHUP;
4520 poll_wait(file, &event->waitq, wait);
4522 if (is_event_hup(event))
4526 * Pin the event->rb by taking event->mmap_mutex; otherwise
4527 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4529 mutex_lock(&event->mmap_mutex);
4532 events = atomic_xchg(&rb->poll, 0);
4533 mutex_unlock(&event->mmap_mutex);
4537 static void _perf_event_reset(struct perf_event *event)
4539 (void)perf_event_read(event, false);
4540 local64_set(&event->count, 0);
4541 perf_event_update_userpage(event);
4545 * Holding the top-level event's child_mutex means that any
4546 * descendant process that has inherited this event will block
4547 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4548 * task existence requirements of perf_event_enable/disable.
4550 static void perf_event_for_each_child(struct perf_event *event,
4551 void (*func)(struct perf_event *))
4553 struct perf_event *child;
4555 WARN_ON_ONCE(event->ctx->parent_ctx);
4557 mutex_lock(&event->child_mutex);
4559 list_for_each_entry(child, &event->child_list, child_list)
4561 mutex_unlock(&event->child_mutex);
4564 static void perf_event_for_each(struct perf_event *event,
4565 void (*func)(struct perf_event *))
4567 struct perf_event_context *ctx = event->ctx;
4568 struct perf_event *sibling;
4570 lockdep_assert_held(&ctx->mutex);
4572 event = event->group_leader;
4574 perf_event_for_each_child(event, func);
4575 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4576 perf_event_for_each_child(sibling, func);
4579 static void __perf_event_period(struct perf_event *event,
4580 struct perf_cpu_context *cpuctx,
4581 struct perf_event_context *ctx,
4584 u64 value = *((u64 *)info);
4587 if (event->attr.freq) {
4588 event->attr.sample_freq = value;
4590 event->attr.sample_period = value;
4591 event->hw.sample_period = value;
4594 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4596 perf_pmu_disable(ctx->pmu);
4598 * We could be throttled; unthrottle now to avoid the tick
4599 * trying to unthrottle while we already re-started the event.
4601 if (event->hw.interrupts == MAX_INTERRUPTS) {
4602 event->hw.interrupts = 0;
4603 perf_log_throttle(event, 1);
4605 event->pmu->stop(event, PERF_EF_UPDATE);
4608 local64_set(&event->hw.period_left, 0);
4611 event->pmu->start(event, PERF_EF_RELOAD);
4612 perf_pmu_enable(ctx->pmu);
4616 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4620 if (!is_sampling_event(event))
4623 if (copy_from_user(&value, arg, sizeof(value)))
4629 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4632 event_function_call(event, __perf_event_period, &value);
4637 static const struct file_operations perf_fops;
4639 static inline int perf_fget_light(int fd, struct fd *p)
4641 struct fd f = fdget(fd);
4645 if (f.file->f_op != &perf_fops) {
4653 static int perf_event_set_output(struct perf_event *event,
4654 struct perf_event *output_event);
4655 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4656 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4658 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4660 void (*func)(struct perf_event *);
4664 case PERF_EVENT_IOC_ENABLE:
4665 func = _perf_event_enable;
4667 case PERF_EVENT_IOC_DISABLE:
4668 func = _perf_event_disable;
4670 case PERF_EVENT_IOC_RESET:
4671 func = _perf_event_reset;
4674 case PERF_EVENT_IOC_REFRESH:
4675 return _perf_event_refresh(event, arg);
4677 case PERF_EVENT_IOC_PERIOD:
4678 return perf_event_period(event, (u64 __user *)arg);
4680 case PERF_EVENT_IOC_ID:
4682 u64 id = primary_event_id(event);
4684 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4689 case PERF_EVENT_IOC_SET_OUTPUT:
4693 struct perf_event *output_event;
4695 ret = perf_fget_light(arg, &output);
4698 output_event = output.file->private_data;
4699 ret = perf_event_set_output(event, output_event);
4702 ret = perf_event_set_output(event, NULL);
4707 case PERF_EVENT_IOC_SET_FILTER:
4708 return perf_event_set_filter(event, (void __user *)arg);
4710 case PERF_EVENT_IOC_SET_BPF:
4711 return perf_event_set_bpf_prog(event, arg);
4713 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4714 struct ring_buffer *rb;
4717 rb = rcu_dereference(event->rb);
4718 if (!rb || !rb->nr_pages) {
4722 rb_toggle_paused(rb, !!arg);
4730 if (flags & PERF_IOC_FLAG_GROUP)
4731 perf_event_for_each(event, func);
4733 perf_event_for_each_child(event, func);
4738 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4740 struct perf_event *event = file->private_data;
4741 struct perf_event_context *ctx;
4744 ctx = perf_event_ctx_lock(event);
4745 ret = _perf_ioctl(event, cmd, arg);
4746 perf_event_ctx_unlock(event, ctx);
4751 #ifdef CONFIG_COMPAT
4752 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4755 switch (_IOC_NR(cmd)) {
4756 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4757 case _IOC_NR(PERF_EVENT_IOC_ID):
4758 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4759 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4760 cmd &= ~IOCSIZE_MASK;
4761 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4765 return perf_ioctl(file, cmd, arg);
4768 # define perf_compat_ioctl NULL
4771 int perf_event_task_enable(void)
4773 struct perf_event_context *ctx;
4774 struct perf_event *event;
4776 mutex_lock(¤t->perf_event_mutex);
4777 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4778 ctx = perf_event_ctx_lock(event);
4779 perf_event_for_each_child(event, _perf_event_enable);
4780 perf_event_ctx_unlock(event, ctx);
4782 mutex_unlock(¤t->perf_event_mutex);
4787 int perf_event_task_disable(void)
4789 struct perf_event_context *ctx;
4790 struct perf_event *event;
4792 mutex_lock(¤t->perf_event_mutex);
4793 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4794 ctx = perf_event_ctx_lock(event);
4795 perf_event_for_each_child(event, _perf_event_disable);
4796 perf_event_ctx_unlock(event, ctx);
4798 mutex_unlock(¤t->perf_event_mutex);
4803 static int perf_event_index(struct perf_event *event)
4805 if (event->hw.state & PERF_HES_STOPPED)
4808 if (event->state != PERF_EVENT_STATE_ACTIVE)
4811 return event->pmu->event_idx(event);
4814 static void calc_timer_values(struct perf_event *event,
4821 *now = perf_clock();
4822 ctx_time = event->shadow_ctx_time + *now;
4823 __perf_update_times(event, ctx_time, enabled, running);
4826 static void perf_event_init_userpage(struct perf_event *event)
4828 struct perf_event_mmap_page *userpg;
4829 struct ring_buffer *rb;
4832 rb = rcu_dereference(event->rb);
4836 userpg = rb->user_page;
4838 /* Allow new userspace to detect that bit 0 is deprecated */
4839 userpg->cap_bit0_is_deprecated = 1;
4840 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4841 userpg->data_offset = PAGE_SIZE;
4842 userpg->data_size = perf_data_size(rb);
4848 void __weak arch_perf_update_userpage(
4849 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4854 * Callers need to ensure there can be no nesting of this function, otherwise
4855 * the seqlock logic goes bad. We can not serialize this because the arch
4856 * code calls this from NMI context.
4858 void perf_event_update_userpage(struct perf_event *event)
4860 struct perf_event_mmap_page *userpg;
4861 struct ring_buffer *rb;
4862 u64 enabled, running, now;
4865 rb = rcu_dereference(event->rb);
4870 * compute total_time_enabled, total_time_running
4871 * based on snapshot values taken when the event
4872 * was last scheduled in.
4874 * we cannot simply called update_context_time()
4875 * because of locking issue as we can be called in
4878 calc_timer_values(event, &now, &enabled, &running);
4880 userpg = rb->user_page;
4882 * Disable preemption so as to not let the corresponding user-space
4883 * spin too long if we get preempted.
4888 userpg->index = perf_event_index(event);
4889 userpg->offset = perf_event_count(event);
4891 userpg->offset -= local64_read(&event->hw.prev_count);
4893 userpg->time_enabled = enabled +
4894 atomic64_read(&event->child_total_time_enabled);
4896 userpg->time_running = running +
4897 atomic64_read(&event->child_total_time_running);
4899 arch_perf_update_userpage(event, userpg, now);
4908 static int perf_mmap_fault(struct vm_fault *vmf)
4910 struct perf_event *event = vmf->vma->vm_file->private_data;
4911 struct ring_buffer *rb;
4912 int ret = VM_FAULT_SIGBUS;
4914 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4915 if (vmf->pgoff == 0)
4921 rb = rcu_dereference(event->rb);
4925 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4928 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4932 get_page(vmf->page);
4933 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4934 vmf->page->index = vmf->pgoff;
4943 static void ring_buffer_attach(struct perf_event *event,
4944 struct ring_buffer *rb)
4946 struct ring_buffer *old_rb = NULL;
4947 unsigned long flags;
4951 * Should be impossible, we set this when removing
4952 * event->rb_entry and wait/clear when adding event->rb_entry.
4954 WARN_ON_ONCE(event->rcu_pending);
4957 spin_lock_irqsave(&old_rb->event_lock, flags);
4958 list_del_rcu(&event->rb_entry);
4959 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4961 event->rcu_batches = get_state_synchronize_rcu();
4962 event->rcu_pending = 1;
4966 if (event->rcu_pending) {
4967 cond_synchronize_rcu(event->rcu_batches);
4968 event->rcu_pending = 0;
4971 spin_lock_irqsave(&rb->event_lock, flags);
4972 list_add_rcu(&event->rb_entry, &rb->event_list);
4973 spin_unlock_irqrestore(&rb->event_lock, flags);
4977 * Avoid racing with perf_mmap_close(AUX): stop the event
4978 * before swizzling the event::rb pointer; if it's getting
4979 * unmapped, its aux_mmap_count will be 0 and it won't
4980 * restart. See the comment in __perf_pmu_output_stop().
4982 * Data will inevitably be lost when set_output is done in
4983 * mid-air, but then again, whoever does it like this is
4984 * not in for the data anyway.
4987 perf_event_stop(event, 0);
4989 rcu_assign_pointer(event->rb, rb);
4992 ring_buffer_put(old_rb);
4994 * Since we detached before setting the new rb, so that we
4995 * could attach the new rb, we could have missed a wakeup.
4998 wake_up_all(&event->waitq);
5002 static void ring_buffer_wakeup(struct perf_event *event)
5004 struct ring_buffer *rb;
5007 rb = rcu_dereference(event->rb);
5009 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5010 wake_up_all(&event->waitq);
5015 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5017 struct ring_buffer *rb;
5020 rb = rcu_dereference(event->rb);
5022 if (!atomic_inc_not_zero(&rb->refcount))
5030 void ring_buffer_put(struct ring_buffer *rb)
5032 if (!atomic_dec_and_test(&rb->refcount))
5035 WARN_ON_ONCE(!list_empty(&rb->event_list));
5037 call_rcu(&rb->rcu_head, rb_free_rcu);
5040 static void perf_mmap_open(struct vm_area_struct *vma)
5042 struct perf_event *event = vma->vm_file->private_data;
5044 atomic_inc(&event->mmap_count);
5045 atomic_inc(&event->rb->mmap_count);
5048 atomic_inc(&event->rb->aux_mmap_count);
5050 if (event->pmu->event_mapped)
5051 event->pmu->event_mapped(event, vma->vm_mm);
5054 static void perf_pmu_output_stop(struct perf_event *event);
5057 * A buffer can be mmap()ed multiple times; either directly through the same
5058 * event, or through other events by use of perf_event_set_output().
5060 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5061 * the buffer here, where we still have a VM context. This means we need
5062 * to detach all events redirecting to us.
5064 static void perf_mmap_close(struct vm_area_struct *vma)
5066 struct perf_event *event = vma->vm_file->private_data;
5068 struct ring_buffer *rb = ring_buffer_get(event);
5069 struct user_struct *mmap_user = rb->mmap_user;
5070 int mmap_locked = rb->mmap_locked;
5071 unsigned long size = perf_data_size(rb);
5073 if (event->pmu->event_unmapped)
5074 event->pmu->event_unmapped(event, vma->vm_mm);
5077 * rb->aux_mmap_count will always drop before rb->mmap_count and
5078 * event->mmap_count, so it is ok to use event->mmap_mutex to
5079 * serialize with perf_mmap here.
5081 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5082 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5084 * Stop all AUX events that are writing to this buffer,
5085 * so that we can free its AUX pages and corresponding PMU
5086 * data. Note that after rb::aux_mmap_count dropped to zero,
5087 * they won't start any more (see perf_aux_output_begin()).
5089 perf_pmu_output_stop(event);
5091 /* now it's safe to free the pages */
5092 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5093 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5095 /* this has to be the last one */
5097 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5099 mutex_unlock(&event->mmap_mutex);
5102 atomic_dec(&rb->mmap_count);
5104 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5107 ring_buffer_attach(event, NULL);
5108 mutex_unlock(&event->mmap_mutex);
5110 /* If there's still other mmap()s of this buffer, we're done. */
5111 if (atomic_read(&rb->mmap_count))
5115 * No other mmap()s, detach from all other events that might redirect
5116 * into the now unreachable buffer. Somewhat complicated by the
5117 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5121 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5122 if (!atomic_long_inc_not_zero(&event->refcount)) {
5124 * This event is en-route to free_event() which will
5125 * detach it and remove it from the list.
5131 mutex_lock(&event->mmap_mutex);
5133 * Check we didn't race with perf_event_set_output() which can
5134 * swizzle the rb from under us while we were waiting to
5135 * acquire mmap_mutex.
5137 * If we find a different rb; ignore this event, a next
5138 * iteration will no longer find it on the list. We have to
5139 * still restart the iteration to make sure we're not now
5140 * iterating the wrong list.
5142 if (event->rb == rb)
5143 ring_buffer_attach(event, NULL);
5145 mutex_unlock(&event->mmap_mutex);
5149 * Restart the iteration; either we're on the wrong list or
5150 * destroyed its integrity by doing a deletion.
5157 * It could be there's still a few 0-ref events on the list; they'll
5158 * get cleaned up by free_event() -- they'll also still have their
5159 * ref on the rb and will free it whenever they are done with it.
5161 * Aside from that, this buffer is 'fully' detached and unmapped,
5162 * undo the VM accounting.
5165 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5166 vma->vm_mm->pinned_vm -= mmap_locked;
5167 free_uid(mmap_user);
5170 ring_buffer_put(rb); /* could be last */
5173 static const struct vm_operations_struct perf_mmap_vmops = {
5174 .open = perf_mmap_open,
5175 .close = perf_mmap_close, /* non mergable */
5176 .fault = perf_mmap_fault,
5177 .page_mkwrite = perf_mmap_fault,
5180 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5182 struct perf_event *event = file->private_data;
5183 unsigned long user_locked, user_lock_limit;
5184 struct user_struct *user = current_user();
5185 unsigned long locked, lock_limit;
5186 struct ring_buffer *rb = NULL;
5187 unsigned long vma_size;
5188 unsigned long nr_pages;
5189 long user_extra = 0, extra = 0;
5190 int ret = 0, flags = 0;
5193 * Don't allow mmap() of inherited per-task counters. This would
5194 * create a performance issue due to all children writing to the
5197 if (event->cpu == -1 && event->attr.inherit)
5200 if (!(vma->vm_flags & VM_SHARED))
5203 vma_size = vma->vm_end - vma->vm_start;
5205 if (vma->vm_pgoff == 0) {
5206 nr_pages = (vma_size / PAGE_SIZE) - 1;
5209 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5210 * mapped, all subsequent mappings should have the same size
5211 * and offset. Must be above the normal perf buffer.
5213 u64 aux_offset, aux_size;
5218 nr_pages = vma_size / PAGE_SIZE;
5220 mutex_lock(&event->mmap_mutex);
5227 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5228 aux_size = READ_ONCE(rb->user_page->aux_size);
5230 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5233 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5236 /* already mapped with a different offset */
5237 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5240 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5243 /* already mapped with a different size */
5244 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5247 if (!is_power_of_2(nr_pages))
5250 if (!atomic_inc_not_zero(&rb->mmap_count))
5253 if (rb_has_aux(rb)) {
5254 atomic_inc(&rb->aux_mmap_count);
5259 atomic_set(&rb->aux_mmap_count, 1);
5260 user_extra = nr_pages;
5266 * If we have rb pages ensure they're a power-of-two number, so we
5267 * can do bitmasks instead of modulo.
5269 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5272 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5275 WARN_ON_ONCE(event->ctx->parent_ctx);
5277 mutex_lock(&event->mmap_mutex);
5279 if (event->rb->nr_pages != nr_pages) {
5284 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5286 * Raced against perf_mmap_close() through
5287 * perf_event_set_output(). Try again, hope for better
5290 mutex_unlock(&event->mmap_mutex);
5297 user_extra = nr_pages + 1;
5300 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5303 * Increase the limit linearly with more CPUs:
5305 user_lock_limit *= num_online_cpus();
5307 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5309 if (user_locked > user_lock_limit)
5310 extra = user_locked - user_lock_limit;
5312 lock_limit = rlimit(RLIMIT_MEMLOCK);
5313 lock_limit >>= PAGE_SHIFT;
5314 locked = vma->vm_mm->pinned_vm + extra;
5316 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5317 !capable(CAP_IPC_LOCK)) {
5322 WARN_ON(!rb && event->rb);
5324 if (vma->vm_flags & VM_WRITE)
5325 flags |= RING_BUFFER_WRITABLE;
5328 rb = rb_alloc(nr_pages,
5329 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5337 atomic_set(&rb->mmap_count, 1);
5338 rb->mmap_user = get_current_user();
5339 rb->mmap_locked = extra;
5341 ring_buffer_attach(event, rb);
5343 perf_event_init_userpage(event);
5344 perf_event_update_userpage(event);
5346 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5347 event->attr.aux_watermark, flags);
5349 rb->aux_mmap_locked = extra;
5354 atomic_long_add(user_extra, &user->locked_vm);
5355 vma->vm_mm->pinned_vm += extra;
5357 atomic_inc(&event->mmap_count);
5359 atomic_dec(&rb->mmap_count);
5362 mutex_unlock(&event->mmap_mutex);
5365 * Since pinned accounting is per vm we cannot allow fork() to copy our
5368 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5369 vma->vm_ops = &perf_mmap_vmops;
5371 if (event->pmu->event_mapped)
5372 event->pmu->event_mapped(event, vma->vm_mm);
5377 static int perf_fasync(int fd, struct file *filp, int on)
5379 struct inode *inode = file_inode(filp);
5380 struct perf_event *event = filp->private_data;
5384 retval = fasync_helper(fd, filp, on, &event->fasync);
5385 inode_unlock(inode);
5393 static const struct file_operations perf_fops = {
5394 .llseek = no_llseek,
5395 .release = perf_release,
5398 .unlocked_ioctl = perf_ioctl,
5399 .compat_ioctl = perf_compat_ioctl,
5401 .fasync = perf_fasync,
5407 * If there's data, ensure we set the poll() state and publish everything
5408 * to user-space before waking everybody up.
5411 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5413 /* only the parent has fasync state */
5415 event = event->parent;
5416 return &event->fasync;
5419 void perf_event_wakeup(struct perf_event *event)
5421 ring_buffer_wakeup(event);
5423 if (event->pending_kill) {
5424 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5425 event->pending_kill = 0;
5429 static void perf_pending_event(struct irq_work *entry)
5431 struct perf_event *event = container_of(entry,
5432 struct perf_event, pending);
5435 rctx = perf_swevent_get_recursion_context();
5437 * If we 'fail' here, that's OK, it means recursion is already disabled
5438 * and we won't recurse 'further'.
5441 if (event->pending_disable) {
5442 event->pending_disable = 0;
5443 perf_event_disable_local(event);
5446 if (event->pending_wakeup) {
5447 event->pending_wakeup = 0;
5448 perf_event_wakeup(event);
5452 perf_swevent_put_recursion_context(rctx);
5456 * We assume there is only KVM supporting the callbacks.
5457 * Later on, we might change it to a list if there is
5458 * another virtualization implementation supporting the callbacks.
5460 struct perf_guest_info_callbacks *perf_guest_cbs;
5462 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5464 perf_guest_cbs = cbs;
5467 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5469 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5471 perf_guest_cbs = NULL;
5474 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5477 perf_output_sample_regs(struct perf_output_handle *handle,
5478 struct pt_regs *regs, u64 mask)
5481 DECLARE_BITMAP(_mask, 64);
5483 bitmap_from_u64(_mask, mask);
5484 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5487 val = perf_reg_value(regs, bit);
5488 perf_output_put(handle, val);
5492 static void perf_sample_regs_user(struct perf_regs *regs_user,
5493 struct pt_regs *regs,
5494 struct pt_regs *regs_user_copy)
5496 if (user_mode(regs)) {
5497 regs_user->abi = perf_reg_abi(current);
5498 regs_user->regs = regs;
5499 } else if (current->mm) {
5500 perf_get_regs_user(regs_user, regs, regs_user_copy);
5502 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5503 regs_user->regs = NULL;
5507 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5508 struct pt_regs *regs)
5510 regs_intr->regs = regs;
5511 regs_intr->abi = perf_reg_abi(current);
5516 * Get remaining task size from user stack pointer.
5518 * It'd be better to take stack vma map and limit this more
5519 * precisly, but there's no way to get it safely under interrupt,
5520 * so using TASK_SIZE as limit.
5522 static u64 perf_ustack_task_size(struct pt_regs *regs)
5524 unsigned long addr = perf_user_stack_pointer(regs);
5526 if (!addr || addr >= TASK_SIZE)
5529 return TASK_SIZE - addr;
5533 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5534 struct pt_regs *regs)
5538 /* No regs, no stack pointer, no dump. */
5543 * Check if we fit in with the requested stack size into the:
5545 * If we don't, we limit the size to the TASK_SIZE.
5547 * - remaining sample size
5548 * If we don't, we customize the stack size to
5549 * fit in to the remaining sample size.
5552 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5553 stack_size = min(stack_size, (u16) task_size);
5555 /* Current header size plus static size and dynamic size. */
5556 header_size += 2 * sizeof(u64);
5558 /* Do we fit in with the current stack dump size? */
5559 if ((u16) (header_size + stack_size) < header_size) {
5561 * If we overflow the maximum size for the sample,
5562 * we customize the stack dump size to fit in.
5564 stack_size = USHRT_MAX - header_size - sizeof(u64);
5565 stack_size = round_up(stack_size, sizeof(u64));
5572 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5573 struct pt_regs *regs)
5575 /* Case of a kernel thread, nothing to dump */
5578 perf_output_put(handle, size);
5587 * - the size requested by user or the best one we can fit
5588 * in to the sample max size
5590 * - user stack dump data
5592 * - the actual dumped size
5596 perf_output_put(handle, dump_size);
5599 sp = perf_user_stack_pointer(regs);
5600 rem = __output_copy_user(handle, (void *) sp, dump_size);
5601 dyn_size = dump_size - rem;
5603 perf_output_skip(handle, rem);
5606 perf_output_put(handle, dyn_size);
5610 static void __perf_event_header__init_id(struct perf_event_header *header,
5611 struct perf_sample_data *data,
5612 struct perf_event *event)
5614 u64 sample_type = event->attr.sample_type;
5616 data->type = sample_type;
5617 header->size += event->id_header_size;
5619 if (sample_type & PERF_SAMPLE_TID) {
5620 /* namespace issues */
5621 data->tid_entry.pid = perf_event_pid(event, current);
5622 data->tid_entry.tid = perf_event_tid(event, current);
5625 if (sample_type & PERF_SAMPLE_TIME)
5626 data->time = perf_event_clock(event);
5628 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5629 data->id = primary_event_id(event);
5631 if (sample_type & PERF_SAMPLE_STREAM_ID)
5632 data->stream_id = event->id;
5634 if (sample_type & PERF_SAMPLE_CPU) {
5635 data->cpu_entry.cpu = raw_smp_processor_id();
5636 data->cpu_entry.reserved = 0;
5640 void perf_event_header__init_id(struct perf_event_header *header,
5641 struct perf_sample_data *data,
5642 struct perf_event *event)
5644 if (event->attr.sample_id_all)
5645 __perf_event_header__init_id(header, data, event);
5648 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5649 struct perf_sample_data *data)
5651 u64 sample_type = data->type;
5653 if (sample_type & PERF_SAMPLE_TID)
5654 perf_output_put(handle, data->tid_entry);
5656 if (sample_type & PERF_SAMPLE_TIME)
5657 perf_output_put(handle, data->time);
5659 if (sample_type & PERF_SAMPLE_ID)
5660 perf_output_put(handle, data->id);
5662 if (sample_type & PERF_SAMPLE_STREAM_ID)
5663 perf_output_put(handle, data->stream_id);
5665 if (sample_type & PERF_SAMPLE_CPU)
5666 perf_output_put(handle, data->cpu_entry);
5668 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5669 perf_output_put(handle, data->id);
5672 void perf_event__output_id_sample(struct perf_event *event,
5673 struct perf_output_handle *handle,
5674 struct perf_sample_data *sample)
5676 if (event->attr.sample_id_all)
5677 __perf_event__output_id_sample(handle, sample);
5680 static void perf_output_read_one(struct perf_output_handle *handle,
5681 struct perf_event *event,
5682 u64 enabled, u64 running)
5684 u64 read_format = event->attr.read_format;
5688 values[n++] = perf_event_count(event);
5689 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5690 values[n++] = enabled +
5691 atomic64_read(&event->child_total_time_enabled);
5693 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5694 values[n++] = running +
5695 atomic64_read(&event->child_total_time_running);
5697 if (read_format & PERF_FORMAT_ID)
5698 values[n++] = primary_event_id(event);
5700 __output_copy(handle, values, n * sizeof(u64));
5703 static void perf_output_read_group(struct perf_output_handle *handle,
5704 struct perf_event *event,
5705 u64 enabled, u64 running)
5707 struct perf_event *leader = event->group_leader, *sub;
5708 u64 read_format = event->attr.read_format;
5712 values[n++] = 1 + leader->nr_siblings;
5714 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5715 values[n++] = enabled;
5717 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5718 values[n++] = running;
5720 if (leader != event)
5721 leader->pmu->read(leader);
5723 values[n++] = perf_event_count(leader);
5724 if (read_format & PERF_FORMAT_ID)
5725 values[n++] = primary_event_id(leader);
5727 __output_copy(handle, values, n * sizeof(u64));
5729 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5732 if ((sub != event) &&
5733 (sub->state == PERF_EVENT_STATE_ACTIVE))
5734 sub->pmu->read(sub);
5736 values[n++] = perf_event_count(sub);
5737 if (read_format & PERF_FORMAT_ID)
5738 values[n++] = primary_event_id(sub);
5740 __output_copy(handle, values, n * sizeof(u64));
5744 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5745 PERF_FORMAT_TOTAL_TIME_RUNNING)
5748 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5750 * The problem is that its both hard and excessively expensive to iterate the
5751 * child list, not to mention that its impossible to IPI the children running
5752 * on another CPU, from interrupt/NMI context.
5754 static void perf_output_read(struct perf_output_handle *handle,
5755 struct perf_event *event)
5757 u64 enabled = 0, running = 0, now;
5758 u64 read_format = event->attr.read_format;
5761 * compute total_time_enabled, total_time_running
5762 * based on snapshot values taken when the event
5763 * was last scheduled in.
5765 * we cannot simply called update_context_time()
5766 * because of locking issue as we are called in
5769 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5770 calc_timer_values(event, &now, &enabled, &running);
5772 if (event->attr.read_format & PERF_FORMAT_GROUP)
5773 perf_output_read_group(handle, event, enabled, running);
5775 perf_output_read_one(handle, event, enabled, running);
5778 void perf_output_sample(struct perf_output_handle *handle,
5779 struct perf_event_header *header,
5780 struct perf_sample_data *data,
5781 struct perf_event *event)
5783 u64 sample_type = data->type;
5785 perf_output_put(handle, *header);
5787 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5788 perf_output_put(handle, data->id);
5790 if (sample_type & PERF_SAMPLE_IP)
5791 perf_output_put(handle, data->ip);
5793 if (sample_type & PERF_SAMPLE_TID)
5794 perf_output_put(handle, data->tid_entry);
5796 if (sample_type & PERF_SAMPLE_TIME)
5797 perf_output_put(handle, data->time);
5799 if (sample_type & PERF_SAMPLE_ADDR)
5800 perf_output_put(handle, data->addr);
5802 if (sample_type & PERF_SAMPLE_ID)
5803 perf_output_put(handle, data->id);
5805 if (sample_type & PERF_SAMPLE_STREAM_ID)
5806 perf_output_put(handle, data->stream_id);
5808 if (sample_type & PERF_SAMPLE_CPU)
5809 perf_output_put(handle, data->cpu_entry);
5811 if (sample_type & PERF_SAMPLE_PERIOD)
5812 perf_output_put(handle, data->period);
5814 if (sample_type & PERF_SAMPLE_READ)
5815 perf_output_read(handle, event);
5817 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5818 if (data->callchain) {
5821 if (data->callchain)
5822 size += data->callchain->nr;
5824 size *= sizeof(u64);
5826 __output_copy(handle, data->callchain, size);
5829 perf_output_put(handle, nr);
5833 if (sample_type & PERF_SAMPLE_RAW) {
5834 struct perf_raw_record *raw = data->raw;
5837 struct perf_raw_frag *frag = &raw->frag;
5839 perf_output_put(handle, raw->size);
5842 __output_custom(handle, frag->copy,
5843 frag->data, frag->size);
5845 __output_copy(handle, frag->data,
5848 if (perf_raw_frag_last(frag))
5853 __output_skip(handle, NULL, frag->pad);
5859 .size = sizeof(u32),
5862 perf_output_put(handle, raw);
5866 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5867 if (data->br_stack) {
5870 size = data->br_stack->nr
5871 * sizeof(struct perf_branch_entry);
5873 perf_output_put(handle, data->br_stack->nr);
5874 perf_output_copy(handle, data->br_stack->entries, size);
5877 * we always store at least the value of nr
5880 perf_output_put(handle, nr);
5884 if (sample_type & PERF_SAMPLE_REGS_USER) {
5885 u64 abi = data->regs_user.abi;
5888 * If there are no regs to dump, notice it through
5889 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5891 perf_output_put(handle, abi);
5894 u64 mask = event->attr.sample_regs_user;
5895 perf_output_sample_regs(handle,
5896 data->regs_user.regs,
5901 if (sample_type & PERF_SAMPLE_STACK_USER) {
5902 perf_output_sample_ustack(handle,
5903 data->stack_user_size,
5904 data->regs_user.regs);
5907 if (sample_type & PERF_SAMPLE_WEIGHT)
5908 perf_output_put(handle, data->weight);
5910 if (sample_type & PERF_SAMPLE_DATA_SRC)
5911 perf_output_put(handle, data->data_src.val);
5913 if (sample_type & PERF_SAMPLE_TRANSACTION)
5914 perf_output_put(handle, data->txn);
5916 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5917 u64 abi = data->regs_intr.abi;
5919 * If there are no regs to dump, notice it through
5920 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5922 perf_output_put(handle, abi);
5925 u64 mask = event->attr.sample_regs_intr;
5927 perf_output_sample_regs(handle,
5928 data->regs_intr.regs,
5933 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
5934 perf_output_put(handle, data->phys_addr);
5936 if (!event->attr.watermark) {
5937 int wakeup_events = event->attr.wakeup_events;
5939 if (wakeup_events) {
5940 struct ring_buffer *rb = handle->rb;
5941 int events = local_inc_return(&rb->events);
5943 if (events >= wakeup_events) {
5944 local_sub(wakeup_events, &rb->events);
5945 local_inc(&rb->wakeup);
5951 static u64 perf_virt_to_phys(u64 virt)
5954 struct page *p = NULL;
5959 if (virt >= TASK_SIZE) {
5960 /* If it's vmalloc()d memory, leave phys_addr as 0 */
5961 if (virt_addr_valid((void *)(uintptr_t)virt) &&
5962 !(virt >= VMALLOC_START && virt < VMALLOC_END))
5963 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
5966 * Walking the pages tables for user address.
5967 * Interrupts are disabled, so it prevents any tear down
5968 * of the page tables.
5969 * Try IRQ-safe __get_user_pages_fast first.
5970 * If failed, leave phys_addr as 0.
5972 if ((current->mm != NULL) &&
5973 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
5974 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
5983 void perf_prepare_sample(struct perf_event_header *header,
5984 struct perf_sample_data *data,
5985 struct perf_event *event,
5986 struct pt_regs *regs)
5988 u64 sample_type = event->attr.sample_type;
5990 header->type = PERF_RECORD_SAMPLE;
5991 header->size = sizeof(*header) + event->header_size;
5994 header->misc |= perf_misc_flags(regs);
5996 __perf_event_header__init_id(header, data, event);
5998 if (sample_type & PERF_SAMPLE_IP)
5999 data->ip = perf_instruction_pointer(regs);
6001 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6004 data->callchain = perf_callchain(event, regs);
6006 if (data->callchain)
6007 size += data->callchain->nr;
6009 header->size += size * sizeof(u64);
6012 if (sample_type & PERF_SAMPLE_RAW) {
6013 struct perf_raw_record *raw = data->raw;
6017 struct perf_raw_frag *frag = &raw->frag;
6022 if (perf_raw_frag_last(frag))
6027 size = round_up(sum + sizeof(u32), sizeof(u64));
6028 raw->size = size - sizeof(u32);
6029 frag->pad = raw->size - sum;
6034 header->size += size;
6037 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6038 int size = sizeof(u64); /* nr */
6039 if (data->br_stack) {
6040 size += data->br_stack->nr
6041 * sizeof(struct perf_branch_entry);
6043 header->size += size;
6046 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6047 perf_sample_regs_user(&data->regs_user, regs,
6048 &data->regs_user_copy);
6050 if (sample_type & PERF_SAMPLE_REGS_USER) {
6051 /* regs dump ABI info */
6052 int size = sizeof(u64);
6054 if (data->regs_user.regs) {
6055 u64 mask = event->attr.sample_regs_user;
6056 size += hweight64(mask) * sizeof(u64);
6059 header->size += size;
6062 if (sample_type & PERF_SAMPLE_STACK_USER) {
6064 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6065 * processed as the last one or have additional check added
6066 * in case new sample type is added, because we could eat
6067 * up the rest of the sample size.
6069 u16 stack_size = event->attr.sample_stack_user;
6070 u16 size = sizeof(u64);
6072 stack_size = perf_sample_ustack_size(stack_size, header->size,
6073 data->regs_user.regs);
6076 * If there is something to dump, add space for the dump
6077 * itself and for the field that tells the dynamic size,
6078 * which is how many have been actually dumped.
6081 size += sizeof(u64) + stack_size;
6083 data->stack_user_size = stack_size;
6084 header->size += size;
6087 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6088 /* regs dump ABI info */
6089 int size = sizeof(u64);
6091 perf_sample_regs_intr(&data->regs_intr, regs);
6093 if (data->regs_intr.regs) {
6094 u64 mask = event->attr.sample_regs_intr;
6096 size += hweight64(mask) * sizeof(u64);
6099 header->size += size;
6102 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6103 data->phys_addr = perf_virt_to_phys(data->addr);
6106 static void __always_inline
6107 __perf_event_output(struct perf_event *event,
6108 struct perf_sample_data *data,
6109 struct pt_regs *regs,
6110 int (*output_begin)(struct perf_output_handle *,
6111 struct perf_event *,
6114 struct perf_output_handle handle;
6115 struct perf_event_header header;
6117 /* protect the callchain buffers */
6120 perf_prepare_sample(&header, data, event, regs);
6122 if (output_begin(&handle, event, header.size))
6125 perf_output_sample(&handle, &header, data, event);
6127 perf_output_end(&handle);
6134 perf_event_output_forward(struct perf_event *event,
6135 struct perf_sample_data *data,
6136 struct pt_regs *regs)
6138 __perf_event_output(event, data, regs, perf_output_begin_forward);
6142 perf_event_output_backward(struct perf_event *event,
6143 struct perf_sample_data *data,
6144 struct pt_regs *regs)
6146 __perf_event_output(event, data, regs, perf_output_begin_backward);
6150 perf_event_output(struct perf_event *event,
6151 struct perf_sample_data *data,
6152 struct pt_regs *regs)
6154 __perf_event_output(event, data, regs, perf_output_begin);
6161 struct perf_read_event {
6162 struct perf_event_header header;
6169 perf_event_read_event(struct perf_event *event,
6170 struct task_struct *task)
6172 struct perf_output_handle handle;
6173 struct perf_sample_data sample;
6174 struct perf_read_event read_event = {
6176 .type = PERF_RECORD_READ,
6178 .size = sizeof(read_event) + event->read_size,
6180 .pid = perf_event_pid(event, task),
6181 .tid = perf_event_tid(event, task),
6185 perf_event_header__init_id(&read_event.header, &sample, event);
6186 ret = perf_output_begin(&handle, event, read_event.header.size);
6190 perf_output_put(&handle, read_event);
6191 perf_output_read(&handle, event);
6192 perf_event__output_id_sample(event, &handle, &sample);
6194 perf_output_end(&handle);
6197 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6200 perf_iterate_ctx(struct perf_event_context *ctx,
6201 perf_iterate_f output,
6202 void *data, bool all)
6204 struct perf_event *event;
6206 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6208 if (event->state < PERF_EVENT_STATE_INACTIVE)
6210 if (!event_filter_match(event))
6214 output(event, data);
6218 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6220 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6221 struct perf_event *event;
6223 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6225 * Skip events that are not fully formed yet; ensure that
6226 * if we observe event->ctx, both event and ctx will be
6227 * complete enough. See perf_install_in_context().
6229 if (!smp_load_acquire(&event->ctx))
6232 if (event->state < PERF_EVENT_STATE_INACTIVE)
6234 if (!event_filter_match(event))
6236 output(event, data);
6241 * Iterate all events that need to receive side-band events.
6243 * For new callers; ensure that account_pmu_sb_event() includes
6244 * your event, otherwise it might not get delivered.
6247 perf_iterate_sb(perf_iterate_f output, void *data,
6248 struct perf_event_context *task_ctx)
6250 struct perf_event_context *ctx;
6257 * If we have task_ctx != NULL we only notify the task context itself.
6258 * The task_ctx is set only for EXIT events before releasing task
6262 perf_iterate_ctx(task_ctx, output, data, false);
6266 perf_iterate_sb_cpu(output, data);
6268 for_each_task_context_nr(ctxn) {
6269 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6271 perf_iterate_ctx(ctx, output, data, false);
6279 * Clear all file-based filters at exec, they'll have to be
6280 * re-instated when/if these objects are mmapped again.
6282 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6284 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6285 struct perf_addr_filter *filter;
6286 unsigned int restart = 0, count = 0;
6287 unsigned long flags;
6289 if (!has_addr_filter(event))
6292 raw_spin_lock_irqsave(&ifh->lock, flags);
6293 list_for_each_entry(filter, &ifh->list, entry) {
6294 if (filter->inode) {
6295 event->addr_filters_offs[count] = 0;
6303 event->addr_filters_gen++;
6304 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6307 perf_event_stop(event, 1);
6310 void perf_event_exec(void)
6312 struct perf_event_context *ctx;
6316 for_each_task_context_nr(ctxn) {
6317 ctx = current->perf_event_ctxp[ctxn];
6321 perf_event_enable_on_exec(ctxn);
6323 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6329 struct remote_output {
6330 struct ring_buffer *rb;
6334 static void __perf_event_output_stop(struct perf_event *event, void *data)
6336 struct perf_event *parent = event->parent;
6337 struct remote_output *ro = data;
6338 struct ring_buffer *rb = ro->rb;
6339 struct stop_event_data sd = {
6343 if (!has_aux(event))
6350 * In case of inheritance, it will be the parent that links to the
6351 * ring-buffer, but it will be the child that's actually using it.
6353 * We are using event::rb to determine if the event should be stopped,
6354 * however this may race with ring_buffer_attach() (through set_output),
6355 * which will make us skip the event that actually needs to be stopped.
6356 * So ring_buffer_attach() has to stop an aux event before re-assigning
6359 if (rcu_dereference(parent->rb) == rb)
6360 ro->err = __perf_event_stop(&sd);
6363 static int __perf_pmu_output_stop(void *info)
6365 struct perf_event *event = info;
6366 struct pmu *pmu = event->pmu;
6367 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6368 struct remote_output ro = {
6373 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6374 if (cpuctx->task_ctx)
6375 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6382 static void perf_pmu_output_stop(struct perf_event *event)
6384 struct perf_event *iter;
6389 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6391 * For per-CPU events, we need to make sure that neither they
6392 * nor their children are running; for cpu==-1 events it's
6393 * sufficient to stop the event itself if it's active, since
6394 * it can't have children.
6398 cpu = READ_ONCE(iter->oncpu);
6403 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6404 if (err == -EAGAIN) {
6413 * task tracking -- fork/exit
6415 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6418 struct perf_task_event {
6419 struct task_struct *task;
6420 struct perf_event_context *task_ctx;
6423 struct perf_event_header header;
6433 static int perf_event_task_match(struct perf_event *event)
6435 return event->attr.comm || event->attr.mmap ||
6436 event->attr.mmap2 || event->attr.mmap_data ||
6440 static void perf_event_task_output(struct perf_event *event,
6443 struct perf_task_event *task_event = data;
6444 struct perf_output_handle handle;
6445 struct perf_sample_data sample;
6446 struct task_struct *task = task_event->task;
6447 int ret, size = task_event->event_id.header.size;
6449 if (!perf_event_task_match(event))
6452 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6454 ret = perf_output_begin(&handle, event,
6455 task_event->event_id.header.size);
6459 task_event->event_id.pid = perf_event_pid(event, task);
6460 task_event->event_id.ppid = perf_event_pid(event, current);
6462 task_event->event_id.tid = perf_event_tid(event, task);
6463 task_event->event_id.ptid = perf_event_tid(event, current);
6465 task_event->event_id.time = perf_event_clock(event);
6467 perf_output_put(&handle, task_event->event_id);
6469 perf_event__output_id_sample(event, &handle, &sample);
6471 perf_output_end(&handle);
6473 task_event->event_id.header.size = size;
6476 static void perf_event_task(struct task_struct *task,
6477 struct perf_event_context *task_ctx,
6480 struct perf_task_event task_event;
6482 if (!atomic_read(&nr_comm_events) &&
6483 !atomic_read(&nr_mmap_events) &&
6484 !atomic_read(&nr_task_events))
6487 task_event = (struct perf_task_event){
6489 .task_ctx = task_ctx,
6492 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6494 .size = sizeof(task_event.event_id),
6504 perf_iterate_sb(perf_event_task_output,
6509 void perf_event_fork(struct task_struct *task)
6511 perf_event_task(task, NULL, 1);
6512 perf_event_namespaces(task);
6519 struct perf_comm_event {
6520 struct task_struct *task;
6525 struct perf_event_header header;
6532 static int perf_event_comm_match(struct perf_event *event)
6534 return event->attr.comm;
6537 static void perf_event_comm_output(struct perf_event *event,
6540 struct perf_comm_event *comm_event = data;
6541 struct perf_output_handle handle;
6542 struct perf_sample_data sample;
6543 int size = comm_event->event_id.header.size;
6546 if (!perf_event_comm_match(event))
6549 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6550 ret = perf_output_begin(&handle, event,
6551 comm_event->event_id.header.size);
6556 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6557 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6559 perf_output_put(&handle, comm_event->event_id);
6560 __output_copy(&handle, comm_event->comm,
6561 comm_event->comm_size);
6563 perf_event__output_id_sample(event, &handle, &sample);
6565 perf_output_end(&handle);
6567 comm_event->event_id.header.size = size;
6570 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6572 char comm[TASK_COMM_LEN];
6575 memset(comm, 0, sizeof(comm));
6576 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6577 size = ALIGN(strlen(comm)+1, sizeof(u64));
6579 comm_event->comm = comm;
6580 comm_event->comm_size = size;
6582 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6584 perf_iterate_sb(perf_event_comm_output,
6589 void perf_event_comm(struct task_struct *task, bool exec)
6591 struct perf_comm_event comm_event;
6593 if (!atomic_read(&nr_comm_events))
6596 comm_event = (struct perf_comm_event){
6602 .type = PERF_RECORD_COMM,
6603 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6611 perf_event_comm_event(&comm_event);
6615 * namespaces tracking
6618 struct perf_namespaces_event {
6619 struct task_struct *task;
6622 struct perf_event_header header;
6627 struct perf_ns_link_info link_info[NR_NAMESPACES];
6631 static int perf_event_namespaces_match(struct perf_event *event)
6633 return event->attr.namespaces;
6636 static void perf_event_namespaces_output(struct perf_event *event,
6639 struct perf_namespaces_event *namespaces_event = data;
6640 struct perf_output_handle handle;
6641 struct perf_sample_data sample;
6644 if (!perf_event_namespaces_match(event))
6647 perf_event_header__init_id(&namespaces_event->event_id.header,
6649 ret = perf_output_begin(&handle, event,
6650 namespaces_event->event_id.header.size);
6654 namespaces_event->event_id.pid = perf_event_pid(event,
6655 namespaces_event->task);
6656 namespaces_event->event_id.tid = perf_event_tid(event,
6657 namespaces_event->task);
6659 perf_output_put(&handle, namespaces_event->event_id);
6661 perf_event__output_id_sample(event, &handle, &sample);
6663 perf_output_end(&handle);
6666 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6667 struct task_struct *task,
6668 const struct proc_ns_operations *ns_ops)
6670 struct path ns_path;
6671 struct inode *ns_inode;
6674 error = ns_get_path(&ns_path, task, ns_ops);
6676 ns_inode = ns_path.dentry->d_inode;
6677 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6678 ns_link_info->ino = ns_inode->i_ino;
6682 void perf_event_namespaces(struct task_struct *task)
6684 struct perf_namespaces_event namespaces_event;
6685 struct perf_ns_link_info *ns_link_info;
6687 if (!atomic_read(&nr_namespaces_events))
6690 namespaces_event = (struct perf_namespaces_event){
6694 .type = PERF_RECORD_NAMESPACES,
6696 .size = sizeof(namespaces_event.event_id),
6700 .nr_namespaces = NR_NAMESPACES,
6701 /* .link_info[NR_NAMESPACES] */
6705 ns_link_info = namespaces_event.event_id.link_info;
6707 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6708 task, &mntns_operations);
6710 #ifdef CONFIG_USER_NS
6711 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6712 task, &userns_operations);
6714 #ifdef CONFIG_NET_NS
6715 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6716 task, &netns_operations);
6718 #ifdef CONFIG_UTS_NS
6719 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6720 task, &utsns_operations);
6722 #ifdef CONFIG_IPC_NS
6723 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6724 task, &ipcns_operations);
6726 #ifdef CONFIG_PID_NS
6727 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6728 task, &pidns_operations);
6730 #ifdef CONFIG_CGROUPS
6731 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6732 task, &cgroupns_operations);
6735 perf_iterate_sb(perf_event_namespaces_output,
6744 struct perf_mmap_event {
6745 struct vm_area_struct *vma;
6747 const char *file_name;
6755 struct perf_event_header header;
6765 static int perf_event_mmap_match(struct perf_event *event,
6768 struct perf_mmap_event *mmap_event = data;
6769 struct vm_area_struct *vma = mmap_event->vma;
6770 int executable = vma->vm_flags & VM_EXEC;
6772 return (!executable && event->attr.mmap_data) ||
6773 (executable && (event->attr.mmap || event->attr.mmap2));
6776 static void perf_event_mmap_output(struct perf_event *event,
6779 struct perf_mmap_event *mmap_event = data;
6780 struct perf_output_handle handle;
6781 struct perf_sample_data sample;
6782 int size = mmap_event->event_id.header.size;
6785 if (!perf_event_mmap_match(event, data))
6788 if (event->attr.mmap2) {
6789 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6790 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6791 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6792 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6793 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6794 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6795 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6798 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6799 ret = perf_output_begin(&handle, event,
6800 mmap_event->event_id.header.size);
6804 mmap_event->event_id.pid = perf_event_pid(event, current);
6805 mmap_event->event_id.tid = perf_event_tid(event, current);
6807 perf_output_put(&handle, mmap_event->event_id);
6809 if (event->attr.mmap2) {
6810 perf_output_put(&handle, mmap_event->maj);
6811 perf_output_put(&handle, mmap_event->min);
6812 perf_output_put(&handle, mmap_event->ino);
6813 perf_output_put(&handle, mmap_event->ino_generation);
6814 perf_output_put(&handle, mmap_event->prot);
6815 perf_output_put(&handle, mmap_event->flags);
6818 __output_copy(&handle, mmap_event->file_name,
6819 mmap_event->file_size);
6821 perf_event__output_id_sample(event, &handle, &sample);
6823 perf_output_end(&handle);
6825 mmap_event->event_id.header.size = size;
6828 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6830 struct vm_area_struct *vma = mmap_event->vma;
6831 struct file *file = vma->vm_file;
6832 int maj = 0, min = 0;
6833 u64 ino = 0, gen = 0;
6834 u32 prot = 0, flags = 0;
6840 if (vma->vm_flags & VM_READ)
6842 if (vma->vm_flags & VM_WRITE)
6844 if (vma->vm_flags & VM_EXEC)
6847 if (vma->vm_flags & VM_MAYSHARE)
6850 flags = MAP_PRIVATE;
6852 if (vma->vm_flags & VM_DENYWRITE)
6853 flags |= MAP_DENYWRITE;
6854 if (vma->vm_flags & VM_MAYEXEC)
6855 flags |= MAP_EXECUTABLE;
6856 if (vma->vm_flags & VM_LOCKED)
6857 flags |= MAP_LOCKED;
6858 if (vma->vm_flags & VM_HUGETLB)
6859 flags |= MAP_HUGETLB;
6862 struct inode *inode;
6865 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6871 * d_path() works from the end of the rb backwards, so we
6872 * need to add enough zero bytes after the string to handle
6873 * the 64bit alignment we do later.
6875 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6880 inode = file_inode(vma->vm_file);
6881 dev = inode->i_sb->s_dev;
6883 gen = inode->i_generation;
6889 if (vma->vm_ops && vma->vm_ops->name) {
6890 name = (char *) vma->vm_ops->name(vma);
6895 name = (char *)arch_vma_name(vma);
6899 if (vma->vm_start <= vma->vm_mm->start_brk &&
6900 vma->vm_end >= vma->vm_mm->brk) {
6904 if (vma->vm_start <= vma->vm_mm->start_stack &&
6905 vma->vm_end >= vma->vm_mm->start_stack) {
6915 strlcpy(tmp, name, sizeof(tmp));
6919 * Since our buffer works in 8 byte units we need to align our string
6920 * size to a multiple of 8. However, we must guarantee the tail end is
6921 * zero'd out to avoid leaking random bits to userspace.
6923 size = strlen(name)+1;
6924 while (!IS_ALIGNED(size, sizeof(u64)))
6925 name[size++] = '\0';
6927 mmap_event->file_name = name;
6928 mmap_event->file_size = size;
6929 mmap_event->maj = maj;
6930 mmap_event->min = min;
6931 mmap_event->ino = ino;
6932 mmap_event->ino_generation = gen;
6933 mmap_event->prot = prot;
6934 mmap_event->flags = flags;
6936 if (!(vma->vm_flags & VM_EXEC))
6937 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6939 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6941 perf_iterate_sb(perf_event_mmap_output,
6949 * Check whether inode and address range match filter criteria.
6951 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6952 struct file *file, unsigned long offset,
6955 if (filter->inode != file_inode(file))
6958 if (filter->offset > offset + size)
6961 if (filter->offset + filter->size < offset)
6967 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6969 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6970 struct vm_area_struct *vma = data;
6971 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6972 struct file *file = vma->vm_file;
6973 struct perf_addr_filter *filter;
6974 unsigned int restart = 0, count = 0;
6976 if (!has_addr_filter(event))
6982 raw_spin_lock_irqsave(&ifh->lock, flags);
6983 list_for_each_entry(filter, &ifh->list, entry) {
6984 if (perf_addr_filter_match(filter, file, off,
6985 vma->vm_end - vma->vm_start)) {
6986 event->addr_filters_offs[count] = vma->vm_start;
6994 event->addr_filters_gen++;
6995 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6998 perf_event_stop(event, 1);
7002 * Adjust all task's events' filters to the new vma
7004 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7006 struct perf_event_context *ctx;
7010 * Data tracing isn't supported yet and as such there is no need
7011 * to keep track of anything that isn't related to executable code:
7013 if (!(vma->vm_flags & VM_EXEC))
7017 for_each_task_context_nr(ctxn) {
7018 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7022 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7027 void perf_event_mmap(struct vm_area_struct *vma)
7029 struct perf_mmap_event mmap_event;
7031 if (!atomic_read(&nr_mmap_events))
7034 mmap_event = (struct perf_mmap_event){
7040 .type = PERF_RECORD_MMAP,
7041 .misc = PERF_RECORD_MISC_USER,
7046 .start = vma->vm_start,
7047 .len = vma->vm_end - vma->vm_start,
7048 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7050 /* .maj (attr_mmap2 only) */
7051 /* .min (attr_mmap2 only) */
7052 /* .ino (attr_mmap2 only) */
7053 /* .ino_generation (attr_mmap2 only) */
7054 /* .prot (attr_mmap2 only) */
7055 /* .flags (attr_mmap2 only) */
7058 perf_addr_filters_adjust(vma);
7059 perf_event_mmap_event(&mmap_event);
7062 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7063 unsigned long size, u64 flags)
7065 struct perf_output_handle handle;
7066 struct perf_sample_data sample;
7067 struct perf_aux_event {
7068 struct perf_event_header header;
7074 .type = PERF_RECORD_AUX,
7076 .size = sizeof(rec),
7084 perf_event_header__init_id(&rec.header, &sample, event);
7085 ret = perf_output_begin(&handle, event, rec.header.size);
7090 perf_output_put(&handle, rec);
7091 perf_event__output_id_sample(event, &handle, &sample);
7093 perf_output_end(&handle);
7097 * Lost/dropped samples logging
7099 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7101 struct perf_output_handle handle;
7102 struct perf_sample_data sample;
7106 struct perf_event_header header;
7108 } lost_samples_event = {
7110 .type = PERF_RECORD_LOST_SAMPLES,
7112 .size = sizeof(lost_samples_event),
7117 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7119 ret = perf_output_begin(&handle, event,
7120 lost_samples_event.header.size);
7124 perf_output_put(&handle, lost_samples_event);
7125 perf_event__output_id_sample(event, &handle, &sample);
7126 perf_output_end(&handle);
7130 * context_switch tracking
7133 struct perf_switch_event {
7134 struct task_struct *task;
7135 struct task_struct *next_prev;
7138 struct perf_event_header header;
7144 static int perf_event_switch_match(struct perf_event *event)
7146 return event->attr.context_switch;
7149 static void perf_event_switch_output(struct perf_event *event, void *data)
7151 struct perf_switch_event *se = data;
7152 struct perf_output_handle handle;
7153 struct perf_sample_data sample;
7156 if (!perf_event_switch_match(event))
7159 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7160 if (event->ctx->task) {
7161 se->event_id.header.type = PERF_RECORD_SWITCH;
7162 se->event_id.header.size = sizeof(se->event_id.header);
7164 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7165 se->event_id.header.size = sizeof(se->event_id);
7166 se->event_id.next_prev_pid =
7167 perf_event_pid(event, se->next_prev);
7168 se->event_id.next_prev_tid =
7169 perf_event_tid(event, se->next_prev);
7172 perf_event_header__init_id(&se->event_id.header, &sample, event);
7174 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7178 if (event->ctx->task)
7179 perf_output_put(&handle, se->event_id.header);
7181 perf_output_put(&handle, se->event_id);
7183 perf_event__output_id_sample(event, &handle, &sample);
7185 perf_output_end(&handle);
7188 static void perf_event_switch(struct task_struct *task,
7189 struct task_struct *next_prev, bool sched_in)
7191 struct perf_switch_event switch_event;
7193 /* N.B. caller checks nr_switch_events != 0 */
7195 switch_event = (struct perf_switch_event){
7197 .next_prev = next_prev,
7201 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7204 /* .next_prev_pid */
7205 /* .next_prev_tid */
7209 perf_iterate_sb(perf_event_switch_output,
7215 * IRQ throttle logging
7218 static void perf_log_throttle(struct perf_event *event, int enable)
7220 struct perf_output_handle handle;
7221 struct perf_sample_data sample;
7225 struct perf_event_header header;
7229 } throttle_event = {
7231 .type = PERF_RECORD_THROTTLE,
7233 .size = sizeof(throttle_event),
7235 .time = perf_event_clock(event),
7236 .id = primary_event_id(event),
7237 .stream_id = event->id,
7241 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7243 perf_event_header__init_id(&throttle_event.header, &sample, event);
7245 ret = perf_output_begin(&handle, event,
7246 throttle_event.header.size);
7250 perf_output_put(&handle, throttle_event);
7251 perf_event__output_id_sample(event, &handle, &sample);
7252 perf_output_end(&handle);
7255 void perf_event_itrace_started(struct perf_event *event)
7257 event->attach_state |= PERF_ATTACH_ITRACE;
7260 static void perf_log_itrace_start(struct perf_event *event)
7262 struct perf_output_handle handle;
7263 struct perf_sample_data sample;
7264 struct perf_aux_event {
7265 struct perf_event_header header;
7272 event = event->parent;
7274 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7275 event->attach_state & PERF_ATTACH_ITRACE)
7278 rec.header.type = PERF_RECORD_ITRACE_START;
7279 rec.header.misc = 0;
7280 rec.header.size = sizeof(rec);
7281 rec.pid = perf_event_pid(event, current);
7282 rec.tid = perf_event_tid(event, current);
7284 perf_event_header__init_id(&rec.header, &sample, event);
7285 ret = perf_output_begin(&handle, event, rec.header.size);
7290 perf_output_put(&handle, rec);
7291 perf_event__output_id_sample(event, &handle, &sample);
7293 perf_output_end(&handle);
7297 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7299 struct hw_perf_event *hwc = &event->hw;
7303 seq = __this_cpu_read(perf_throttled_seq);
7304 if (seq != hwc->interrupts_seq) {
7305 hwc->interrupts_seq = seq;
7306 hwc->interrupts = 1;
7309 if (unlikely(throttle
7310 && hwc->interrupts >= max_samples_per_tick)) {
7311 __this_cpu_inc(perf_throttled_count);
7312 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7313 hwc->interrupts = MAX_INTERRUPTS;
7314 perf_log_throttle(event, 0);
7319 if (event->attr.freq) {
7320 u64 now = perf_clock();
7321 s64 delta = now - hwc->freq_time_stamp;
7323 hwc->freq_time_stamp = now;
7325 if (delta > 0 && delta < 2*TICK_NSEC)
7326 perf_adjust_period(event, delta, hwc->last_period, true);
7332 int perf_event_account_interrupt(struct perf_event *event)
7334 return __perf_event_account_interrupt(event, 1);
7338 * Generic event overflow handling, sampling.
7341 static int __perf_event_overflow(struct perf_event *event,
7342 int throttle, struct perf_sample_data *data,
7343 struct pt_regs *regs)
7345 int events = atomic_read(&event->event_limit);
7349 * Non-sampling counters might still use the PMI to fold short
7350 * hardware counters, ignore those.
7352 if (unlikely(!is_sampling_event(event)))
7355 ret = __perf_event_account_interrupt(event, throttle);
7358 * XXX event_limit might not quite work as expected on inherited
7362 event->pending_kill = POLL_IN;
7363 if (events && atomic_dec_and_test(&event->event_limit)) {
7365 event->pending_kill = POLL_HUP;
7367 perf_event_disable_inatomic(event);
7370 READ_ONCE(event->overflow_handler)(event, data, regs);
7372 if (*perf_event_fasync(event) && event->pending_kill) {
7373 event->pending_wakeup = 1;
7374 irq_work_queue(&event->pending);
7380 int perf_event_overflow(struct perf_event *event,
7381 struct perf_sample_data *data,
7382 struct pt_regs *regs)
7384 return __perf_event_overflow(event, 1, data, regs);
7388 * Generic software event infrastructure
7391 struct swevent_htable {
7392 struct swevent_hlist *swevent_hlist;
7393 struct mutex hlist_mutex;
7396 /* Recursion avoidance in each contexts */
7397 int recursion[PERF_NR_CONTEXTS];
7400 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7403 * We directly increment event->count and keep a second value in
7404 * event->hw.period_left to count intervals. This period event
7405 * is kept in the range [-sample_period, 0] so that we can use the
7409 u64 perf_swevent_set_period(struct perf_event *event)
7411 struct hw_perf_event *hwc = &event->hw;
7412 u64 period = hwc->last_period;
7416 hwc->last_period = hwc->sample_period;
7419 old = val = local64_read(&hwc->period_left);
7423 nr = div64_u64(period + val, period);
7424 offset = nr * period;
7426 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7432 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7433 struct perf_sample_data *data,
7434 struct pt_regs *regs)
7436 struct hw_perf_event *hwc = &event->hw;
7440 overflow = perf_swevent_set_period(event);
7442 if (hwc->interrupts == MAX_INTERRUPTS)
7445 for (; overflow; overflow--) {
7446 if (__perf_event_overflow(event, throttle,
7449 * We inhibit the overflow from happening when
7450 * hwc->interrupts == MAX_INTERRUPTS.
7458 static void perf_swevent_event(struct perf_event *event, u64 nr,
7459 struct perf_sample_data *data,
7460 struct pt_regs *regs)
7462 struct hw_perf_event *hwc = &event->hw;
7464 local64_add(nr, &event->count);
7469 if (!is_sampling_event(event))
7472 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7474 return perf_swevent_overflow(event, 1, data, regs);
7476 data->period = event->hw.last_period;
7478 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7479 return perf_swevent_overflow(event, 1, data, regs);
7481 if (local64_add_negative(nr, &hwc->period_left))
7484 perf_swevent_overflow(event, 0, data, regs);
7487 static int perf_exclude_event(struct perf_event *event,
7488 struct pt_regs *regs)
7490 if (event->hw.state & PERF_HES_STOPPED)
7494 if (event->attr.exclude_user && user_mode(regs))
7497 if (event->attr.exclude_kernel && !user_mode(regs))
7504 static int perf_swevent_match(struct perf_event *event,
7505 enum perf_type_id type,
7507 struct perf_sample_data *data,
7508 struct pt_regs *regs)
7510 if (event->attr.type != type)
7513 if (event->attr.config != event_id)
7516 if (perf_exclude_event(event, regs))
7522 static inline u64 swevent_hash(u64 type, u32 event_id)
7524 u64 val = event_id | (type << 32);
7526 return hash_64(val, SWEVENT_HLIST_BITS);
7529 static inline struct hlist_head *
7530 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7532 u64 hash = swevent_hash(type, event_id);
7534 return &hlist->heads[hash];
7537 /* For the read side: events when they trigger */
7538 static inline struct hlist_head *
7539 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7541 struct swevent_hlist *hlist;
7543 hlist = rcu_dereference(swhash->swevent_hlist);
7547 return __find_swevent_head(hlist, type, event_id);
7550 /* For the event head insertion and removal in the hlist */
7551 static inline struct hlist_head *
7552 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7554 struct swevent_hlist *hlist;
7555 u32 event_id = event->attr.config;
7556 u64 type = event->attr.type;
7559 * Event scheduling is always serialized against hlist allocation
7560 * and release. Which makes the protected version suitable here.
7561 * The context lock guarantees that.
7563 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7564 lockdep_is_held(&event->ctx->lock));
7568 return __find_swevent_head(hlist, type, event_id);
7571 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7573 struct perf_sample_data *data,
7574 struct pt_regs *regs)
7576 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7577 struct perf_event *event;
7578 struct hlist_head *head;
7581 head = find_swevent_head_rcu(swhash, type, event_id);
7585 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7586 if (perf_swevent_match(event, type, event_id, data, regs))
7587 perf_swevent_event(event, nr, data, regs);
7593 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7595 int perf_swevent_get_recursion_context(void)
7597 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7599 return get_recursion_context(swhash->recursion);
7601 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7603 void perf_swevent_put_recursion_context(int rctx)
7605 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7607 put_recursion_context(swhash->recursion, rctx);
7610 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7612 struct perf_sample_data data;
7614 if (WARN_ON_ONCE(!regs))
7617 perf_sample_data_init(&data, addr, 0);
7618 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7621 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7625 preempt_disable_notrace();
7626 rctx = perf_swevent_get_recursion_context();
7627 if (unlikely(rctx < 0))
7630 ___perf_sw_event(event_id, nr, regs, addr);
7632 perf_swevent_put_recursion_context(rctx);
7634 preempt_enable_notrace();
7637 static void perf_swevent_read(struct perf_event *event)
7641 static int perf_swevent_add(struct perf_event *event, int flags)
7643 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7644 struct hw_perf_event *hwc = &event->hw;
7645 struct hlist_head *head;
7647 if (is_sampling_event(event)) {
7648 hwc->last_period = hwc->sample_period;
7649 perf_swevent_set_period(event);
7652 hwc->state = !(flags & PERF_EF_START);
7654 head = find_swevent_head(swhash, event);
7655 if (WARN_ON_ONCE(!head))
7658 hlist_add_head_rcu(&event->hlist_entry, head);
7659 perf_event_update_userpage(event);
7664 static void perf_swevent_del(struct perf_event *event, int flags)
7666 hlist_del_rcu(&event->hlist_entry);
7669 static void perf_swevent_start(struct perf_event *event, int flags)
7671 event->hw.state = 0;
7674 static void perf_swevent_stop(struct perf_event *event, int flags)
7676 event->hw.state = PERF_HES_STOPPED;
7679 /* Deref the hlist from the update side */
7680 static inline struct swevent_hlist *
7681 swevent_hlist_deref(struct swevent_htable *swhash)
7683 return rcu_dereference_protected(swhash->swevent_hlist,
7684 lockdep_is_held(&swhash->hlist_mutex));
7687 static void swevent_hlist_release(struct swevent_htable *swhash)
7689 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7694 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7695 kfree_rcu(hlist, rcu_head);
7698 static void swevent_hlist_put_cpu(int cpu)
7700 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7702 mutex_lock(&swhash->hlist_mutex);
7704 if (!--swhash->hlist_refcount)
7705 swevent_hlist_release(swhash);
7707 mutex_unlock(&swhash->hlist_mutex);
7710 static void swevent_hlist_put(void)
7714 for_each_possible_cpu(cpu)
7715 swevent_hlist_put_cpu(cpu);
7718 static int swevent_hlist_get_cpu(int cpu)
7720 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7723 mutex_lock(&swhash->hlist_mutex);
7724 if (!swevent_hlist_deref(swhash) &&
7725 cpumask_test_cpu(cpu, perf_online_mask)) {
7726 struct swevent_hlist *hlist;
7728 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7733 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7735 swhash->hlist_refcount++;
7737 mutex_unlock(&swhash->hlist_mutex);
7742 static int swevent_hlist_get(void)
7744 int err, cpu, failed_cpu;
7746 mutex_lock(&pmus_lock);
7747 for_each_possible_cpu(cpu) {
7748 err = swevent_hlist_get_cpu(cpu);
7754 mutex_unlock(&pmus_lock);
7757 for_each_possible_cpu(cpu) {
7758 if (cpu == failed_cpu)
7760 swevent_hlist_put_cpu(cpu);
7762 mutex_unlock(&pmus_lock);
7766 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7768 static void sw_perf_event_destroy(struct perf_event *event)
7770 u64 event_id = event->attr.config;
7772 WARN_ON(event->parent);
7774 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7775 swevent_hlist_put();
7778 static int perf_swevent_init(struct perf_event *event)
7780 u64 event_id = event->attr.config;
7782 if (event->attr.type != PERF_TYPE_SOFTWARE)
7786 * no branch sampling for software events
7788 if (has_branch_stack(event))
7792 case PERF_COUNT_SW_CPU_CLOCK:
7793 case PERF_COUNT_SW_TASK_CLOCK:
7800 if (event_id >= PERF_COUNT_SW_MAX)
7803 if (!event->parent) {
7806 err = swevent_hlist_get();
7810 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7811 event->destroy = sw_perf_event_destroy;
7817 static struct pmu perf_swevent = {
7818 .task_ctx_nr = perf_sw_context,
7820 .capabilities = PERF_PMU_CAP_NO_NMI,
7822 .event_init = perf_swevent_init,
7823 .add = perf_swevent_add,
7824 .del = perf_swevent_del,
7825 .start = perf_swevent_start,
7826 .stop = perf_swevent_stop,
7827 .read = perf_swevent_read,
7830 #ifdef CONFIG_EVENT_TRACING
7832 static int perf_tp_filter_match(struct perf_event *event,
7833 struct perf_sample_data *data)
7835 void *record = data->raw->frag.data;
7837 /* only top level events have filters set */
7839 event = event->parent;
7841 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7846 static int perf_tp_event_match(struct perf_event *event,
7847 struct perf_sample_data *data,
7848 struct pt_regs *regs)
7850 if (event->hw.state & PERF_HES_STOPPED)
7853 * All tracepoints are from kernel-space.
7855 if (event->attr.exclude_kernel)
7858 if (!perf_tp_filter_match(event, data))
7864 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7865 struct trace_event_call *call, u64 count,
7866 struct pt_regs *regs, struct hlist_head *head,
7867 struct task_struct *task)
7869 if (bpf_prog_array_valid(call)) {
7870 *(struct pt_regs **)raw_data = regs;
7871 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
7872 perf_swevent_put_recursion_context(rctx);
7876 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7879 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7881 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7882 struct pt_regs *regs, struct hlist_head *head, int rctx,
7883 struct task_struct *task)
7885 struct perf_sample_data data;
7886 struct perf_event *event;
7888 struct perf_raw_record raw = {
7895 perf_sample_data_init(&data, 0, 0);
7898 perf_trace_buf_update(record, event_type);
7900 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7901 if (perf_tp_event_match(event, &data, regs))
7902 perf_swevent_event(event, count, &data, regs);
7906 * If we got specified a target task, also iterate its context and
7907 * deliver this event there too.
7909 if (task && task != current) {
7910 struct perf_event_context *ctx;
7911 struct trace_entry *entry = record;
7914 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7918 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7919 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7921 if (event->attr.config != entry->type)
7923 if (perf_tp_event_match(event, &data, regs))
7924 perf_swevent_event(event, count, &data, regs);
7930 perf_swevent_put_recursion_context(rctx);
7932 EXPORT_SYMBOL_GPL(perf_tp_event);
7934 static void tp_perf_event_destroy(struct perf_event *event)
7936 perf_trace_destroy(event);
7939 static int perf_tp_event_init(struct perf_event *event)
7943 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7947 * no branch sampling for tracepoint events
7949 if (has_branch_stack(event))
7952 err = perf_trace_init(event);
7956 event->destroy = tp_perf_event_destroy;
7961 static struct pmu perf_tracepoint = {
7962 .task_ctx_nr = perf_sw_context,
7964 .event_init = perf_tp_event_init,
7965 .add = perf_trace_add,
7966 .del = perf_trace_del,
7967 .start = perf_swevent_start,
7968 .stop = perf_swevent_stop,
7969 .read = perf_swevent_read,
7972 static inline void perf_tp_register(void)
7974 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7977 static void perf_event_free_filter(struct perf_event *event)
7979 ftrace_profile_free_filter(event);
7982 #ifdef CONFIG_BPF_SYSCALL
7983 static void bpf_overflow_handler(struct perf_event *event,
7984 struct perf_sample_data *data,
7985 struct pt_regs *regs)
7987 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, is_syscall_tp;
8054 struct bpf_prog *prog;
8057 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8058 return perf_event_set_bpf_handler(event, prog_fd);
8060 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8061 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8062 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8063 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8064 /* bpf programs can only be attached to u/kprobe or tracepoint */
8067 prog = bpf_prog_get(prog_fd);
8069 return PTR_ERR(prog);
8071 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8072 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8073 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8074 /* valid fd, but invalid bpf program type */
8079 if (is_tracepoint || is_syscall_tp) {
8080 int off = trace_event_get_offsets(event->tp_event);
8082 if (prog->aux->max_ctx_offset > off) {
8088 ret = perf_event_attach_bpf_prog(event, prog);
8094 static void perf_event_free_bpf_prog(struct perf_event *event)
8096 if (event->attr.type != PERF_TYPE_TRACEPOINT) {
8097 perf_event_free_bpf_handler(event);
8100 perf_event_detach_bpf_prog(event);
8105 static inline void perf_tp_register(void)
8109 static void perf_event_free_filter(struct perf_event *event)
8113 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8118 static void perf_event_free_bpf_prog(struct perf_event *event)
8121 #endif /* CONFIG_EVENT_TRACING */
8123 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8124 void perf_bp_event(struct perf_event *bp, void *data)
8126 struct perf_sample_data sample;
8127 struct pt_regs *regs = data;
8129 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8131 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8132 perf_swevent_event(bp, 1, &sample, regs);
8137 * Allocate a new address filter
8139 static struct perf_addr_filter *
8140 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8142 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8143 struct perf_addr_filter *filter;
8145 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8149 INIT_LIST_HEAD(&filter->entry);
8150 list_add_tail(&filter->entry, filters);
8155 static void free_filters_list(struct list_head *filters)
8157 struct perf_addr_filter *filter, *iter;
8159 list_for_each_entry_safe(filter, iter, filters, entry) {
8161 iput(filter->inode);
8162 list_del(&filter->entry);
8168 * Free existing address filters and optionally install new ones
8170 static void perf_addr_filters_splice(struct perf_event *event,
8171 struct list_head *head)
8173 unsigned long flags;
8176 if (!has_addr_filter(event))
8179 /* don't bother with children, they don't have their own filters */
8183 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8185 list_splice_init(&event->addr_filters.list, &list);
8187 list_splice(head, &event->addr_filters.list);
8189 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8191 free_filters_list(&list);
8195 * Scan through mm's vmas and see if one of them matches the
8196 * @filter; if so, adjust filter's address range.
8197 * Called with mm::mmap_sem down for reading.
8199 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8200 struct mm_struct *mm)
8202 struct vm_area_struct *vma;
8204 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8205 struct file *file = vma->vm_file;
8206 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8207 unsigned long vma_size = vma->vm_end - vma->vm_start;
8212 if (!perf_addr_filter_match(filter, file, off, vma_size))
8215 return vma->vm_start;
8222 * Update event's address range filters based on the
8223 * task's existing mappings, if any.
8225 static void perf_event_addr_filters_apply(struct perf_event *event)
8227 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8228 struct task_struct *task = READ_ONCE(event->ctx->task);
8229 struct perf_addr_filter *filter;
8230 struct mm_struct *mm = NULL;
8231 unsigned int count = 0;
8232 unsigned long flags;
8235 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8236 * will stop on the parent's child_mutex that our caller is also holding
8238 if (task == TASK_TOMBSTONE)
8241 if (!ifh->nr_file_filters)
8244 mm = get_task_mm(event->ctx->task);
8248 down_read(&mm->mmap_sem);
8250 raw_spin_lock_irqsave(&ifh->lock, flags);
8251 list_for_each_entry(filter, &ifh->list, entry) {
8252 event->addr_filters_offs[count] = 0;
8255 * Adjust base offset if the filter is associated to a binary
8256 * that needs to be mapped:
8259 event->addr_filters_offs[count] =
8260 perf_addr_filter_apply(filter, mm);
8265 event->addr_filters_gen++;
8266 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8268 up_read(&mm->mmap_sem);
8273 perf_event_stop(event, 1);
8277 * Address range filtering: limiting the data to certain
8278 * instruction address ranges. Filters are ioctl()ed to us from
8279 * userspace as ascii strings.
8281 * Filter string format:
8284 * where ACTION is one of the
8285 * * "filter": limit the trace to this region
8286 * * "start": start tracing from this address
8287 * * "stop": stop tracing at this address/region;
8289 * * for kernel addresses: <start address>[/<size>]
8290 * * for object files: <start address>[/<size>]@</path/to/object/file>
8292 * if <size> is not specified, the range is treated as a single address.
8306 IF_STATE_ACTION = 0,
8311 static const match_table_t if_tokens = {
8312 { IF_ACT_FILTER, "filter" },
8313 { IF_ACT_START, "start" },
8314 { IF_ACT_STOP, "stop" },
8315 { IF_SRC_FILE, "%u/%u@%s" },
8316 { IF_SRC_KERNEL, "%u/%u" },
8317 { IF_SRC_FILEADDR, "%u@%s" },
8318 { IF_SRC_KERNELADDR, "%u" },
8319 { IF_ACT_NONE, NULL },
8323 * Address filter string parser
8326 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8327 struct list_head *filters)
8329 struct perf_addr_filter *filter = NULL;
8330 char *start, *orig, *filename = NULL;
8332 substring_t args[MAX_OPT_ARGS];
8333 int state = IF_STATE_ACTION, token;
8334 unsigned int kernel = 0;
8337 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8341 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8347 /* filter definition begins */
8348 if (state == IF_STATE_ACTION) {
8349 filter = perf_addr_filter_new(event, filters);
8354 token = match_token(start, if_tokens, args);
8361 if (state != IF_STATE_ACTION)
8364 state = IF_STATE_SOURCE;
8367 case IF_SRC_KERNELADDR:
8371 case IF_SRC_FILEADDR:
8373 if (state != IF_STATE_SOURCE)
8376 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8380 ret = kstrtoul(args[0].from, 0, &filter->offset);
8384 if (filter->range) {
8386 ret = kstrtoul(args[1].from, 0, &filter->size);
8391 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8392 int fpos = filter->range ? 2 : 1;
8394 filename = match_strdup(&args[fpos]);
8401 state = IF_STATE_END;
8409 * Filter definition is fully parsed, validate and install it.
8410 * Make sure that it doesn't contradict itself or the event's
8413 if (state == IF_STATE_END) {
8415 if (kernel && event->attr.exclude_kernel)
8423 * For now, we only support file-based filters
8424 * in per-task events; doing so for CPU-wide
8425 * events requires additional context switching
8426 * trickery, since same object code will be
8427 * mapped at different virtual addresses in
8428 * different processes.
8431 if (!event->ctx->task)
8432 goto fail_free_name;
8434 /* look up the path and grab its inode */
8435 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8437 goto fail_free_name;
8439 filter->inode = igrab(d_inode(path.dentry));
8445 if (!filter->inode ||
8446 !S_ISREG(filter->inode->i_mode))
8447 /* free_filters_list() will iput() */
8450 event->addr_filters.nr_file_filters++;
8453 /* ready to consume more filters */
8454 state = IF_STATE_ACTION;
8459 if (state != IF_STATE_ACTION)
8469 free_filters_list(filters);
8476 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8482 * Since this is called in perf_ioctl() path, we're already holding
8485 lockdep_assert_held(&event->ctx->mutex);
8487 if (WARN_ON_ONCE(event->parent))
8490 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8492 goto fail_clear_files;
8494 ret = event->pmu->addr_filters_validate(&filters);
8496 goto fail_free_filters;
8498 /* remove existing filters, if any */
8499 perf_addr_filters_splice(event, &filters);
8501 /* install new filters */
8502 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8507 free_filters_list(&filters);
8510 event->addr_filters.nr_file_filters = 0;
8515 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8520 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8521 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8522 !has_addr_filter(event))
8525 filter_str = strndup_user(arg, PAGE_SIZE);
8526 if (IS_ERR(filter_str))
8527 return PTR_ERR(filter_str);
8529 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8530 event->attr.type == PERF_TYPE_TRACEPOINT)
8531 ret = ftrace_profile_set_filter(event, event->attr.config,
8533 else if (has_addr_filter(event))
8534 ret = perf_event_set_addr_filter(event, filter_str);
8541 * hrtimer based swevent callback
8544 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8546 enum hrtimer_restart ret = HRTIMER_RESTART;
8547 struct perf_sample_data data;
8548 struct pt_regs *regs;
8549 struct perf_event *event;
8552 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8554 if (event->state != PERF_EVENT_STATE_ACTIVE)
8555 return HRTIMER_NORESTART;
8557 event->pmu->read(event);
8559 perf_sample_data_init(&data, 0, event->hw.last_period);
8560 regs = get_irq_regs();
8562 if (regs && !perf_exclude_event(event, regs)) {
8563 if (!(event->attr.exclude_idle && is_idle_task(current)))
8564 if (__perf_event_overflow(event, 1, &data, regs))
8565 ret = HRTIMER_NORESTART;
8568 period = max_t(u64, 10000, event->hw.sample_period);
8569 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8574 static void perf_swevent_start_hrtimer(struct perf_event *event)
8576 struct hw_perf_event *hwc = &event->hw;
8579 if (!is_sampling_event(event))
8582 period = local64_read(&hwc->period_left);
8587 local64_set(&hwc->period_left, 0);
8589 period = max_t(u64, 10000, hwc->sample_period);
8591 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8592 HRTIMER_MODE_REL_PINNED);
8595 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8597 struct hw_perf_event *hwc = &event->hw;
8599 if (is_sampling_event(event)) {
8600 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8601 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8603 hrtimer_cancel(&hwc->hrtimer);
8607 static void perf_swevent_init_hrtimer(struct perf_event *event)
8609 struct hw_perf_event *hwc = &event->hw;
8611 if (!is_sampling_event(event))
8614 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8615 hwc->hrtimer.function = perf_swevent_hrtimer;
8618 * Since hrtimers have a fixed rate, we can do a static freq->period
8619 * mapping and avoid the whole period adjust feedback stuff.
8621 if (event->attr.freq) {
8622 long freq = event->attr.sample_freq;
8624 event->attr.sample_period = NSEC_PER_SEC / freq;
8625 hwc->sample_period = event->attr.sample_period;
8626 local64_set(&hwc->period_left, hwc->sample_period);
8627 hwc->last_period = hwc->sample_period;
8628 event->attr.freq = 0;
8633 * Software event: cpu wall time clock
8636 static void cpu_clock_event_update(struct perf_event *event)
8641 now = local_clock();
8642 prev = local64_xchg(&event->hw.prev_count, now);
8643 local64_add(now - prev, &event->count);
8646 static void cpu_clock_event_start(struct perf_event *event, int flags)
8648 local64_set(&event->hw.prev_count, local_clock());
8649 perf_swevent_start_hrtimer(event);
8652 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8654 perf_swevent_cancel_hrtimer(event);
8655 cpu_clock_event_update(event);
8658 static int cpu_clock_event_add(struct perf_event *event, int flags)
8660 if (flags & PERF_EF_START)
8661 cpu_clock_event_start(event, flags);
8662 perf_event_update_userpage(event);
8667 static void cpu_clock_event_del(struct perf_event *event, int flags)
8669 cpu_clock_event_stop(event, flags);
8672 static void cpu_clock_event_read(struct perf_event *event)
8674 cpu_clock_event_update(event);
8677 static int cpu_clock_event_init(struct perf_event *event)
8679 if (event->attr.type != PERF_TYPE_SOFTWARE)
8682 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8686 * no branch sampling for software events
8688 if (has_branch_stack(event))
8691 perf_swevent_init_hrtimer(event);
8696 static struct pmu perf_cpu_clock = {
8697 .task_ctx_nr = perf_sw_context,
8699 .capabilities = PERF_PMU_CAP_NO_NMI,
8701 .event_init = cpu_clock_event_init,
8702 .add = cpu_clock_event_add,
8703 .del = cpu_clock_event_del,
8704 .start = cpu_clock_event_start,
8705 .stop = cpu_clock_event_stop,
8706 .read = cpu_clock_event_read,
8710 * Software event: task time clock
8713 static void task_clock_event_update(struct perf_event *event, u64 now)
8718 prev = local64_xchg(&event->hw.prev_count, now);
8720 local64_add(delta, &event->count);
8723 static void task_clock_event_start(struct perf_event *event, int flags)
8725 local64_set(&event->hw.prev_count, event->ctx->time);
8726 perf_swevent_start_hrtimer(event);
8729 static void task_clock_event_stop(struct perf_event *event, int flags)
8731 perf_swevent_cancel_hrtimer(event);
8732 task_clock_event_update(event, event->ctx->time);
8735 static int task_clock_event_add(struct perf_event *event, int flags)
8737 if (flags & PERF_EF_START)
8738 task_clock_event_start(event, flags);
8739 perf_event_update_userpage(event);
8744 static void task_clock_event_del(struct perf_event *event, int flags)
8746 task_clock_event_stop(event, PERF_EF_UPDATE);
8749 static void task_clock_event_read(struct perf_event *event)
8751 u64 now = perf_clock();
8752 u64 delta = now - event->ctx->timestamp;
8753 u64 time = event->ctx->time + delta;
8755 task_clock_event_update(event, time);
8758 static int task_clock_event_init(struct perf_event *event)
8760 if (event->attr.type != PERF_TYPE_SOFTWARE)
8763 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8767 * no branch sampling for software events
8769 if (has_branch_stack(event))
8772 perf_swevent_init_hrtimer(event);
8777 static struct pmu perf_task_clock = {
8778 .task_ctx_nr = perf_sw_context,
8780 .capabilities = PERF_PMU_CAP_NO_NMI,
8782 .event_init = task_clock_event_init,
8783 .add = task_clock_event_add,
8784 .del = task_clock_event_del,
8785 .start = task_clock_event_start,
8786 .stop = task_clock_event_stop,
8787 .read = task_clock_event_read,
8790 static void perf_pmu_nop_void(struct pmu *pmu)
8794 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8798 static int perf_pmu_nop_int(struct pmu *pmu)
8803 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8805 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8807 __this_cpu_write(nop_txn_flags, flags);
8809 if (flags & ~PERF_PMU_TXN_ADD)
8812 perf_pmu_disable(pmu);
8815 static int perf_pmu_commit_txn(struct pmu *pmu)
8817 unsigned int flags = __this_cpu_read(nop_txn_flags);
8819 __this_cpu_write(nop_txn_flags, 0);
8821 if (flags & ~PERF_PMU_TXN_ADD)
8824 perf_pmu_enable(pmu);
8828 static void perf_pmu_cancel_txn(struct pmu *pmu)
8830 unsigned int flags = __this_cpu_read(nop_txn_flags);
8832 __this_cpu_write(nop_txn_flags, 0);
8834 if (flags & ~PERF_PMU_TXN_ADD)
8837 perf_pmu_enable(pmu);
8840 static int perf_event_idx_default(struct perf_event *event)
8846 * Ensures all contexts with the same task_ctx_nr have the same
8847 * pmu_cpu_context too.
8849 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8856 list_for_each_entry(pmu, &pmus, entry) {
8857 if (pmu->task_ctx_nr == ctxn)
8858 return pmu->pmu_cpu_context;
8864 static void free_pmu_context(struct pmu *pmu)
8867 * Static contexts such as perf_sw_context have a global lifetime
8868 * and may be shared between different PMUs. Avoid freeing them
8869 * when a single PMU is going away.
8871 if (pmu->task_ctx_nr > perf_invalid_context)
8874 mutex_lock(&pmus_lock);
8875 free_percpu(pmu->pmu_cpu_context);
8876 mutex_unlock(&pmus_lock);
8880 * Let userspace know that this PMU supports address range filtering:
8882 static ssize_t nr_addr_filters_show(struct device *dev,
8883 struct device_attribute *attr,
8886 struct pmu *pmu = dev_get_drvdata(dev);
8888 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8890 DEVICE_ATTR_RO(nr_addr_filters);
8892 static struct idr pmu_idr;
8895 type_show(struct device *dev, struct device_attribute *attr, char *page)
8897 struct pmu *pmu = dev_get_drvdata(dev);
8899 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8901 static DEVICE_ATTR_RO(type);
8904 perf_event_mux_interval_ms_show(struct device *dev,
8905 struct device_attribute *attr,
8908 struct pmu *pmu = dev_get_drvdata(dev);
8910 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8913 static DEFINE_MUTEX(mux_interval_mutex);
8916 perf_event_mux_interval_ms_store(struct device *dev,
8917 struct device_attribute *attr,
8918 const char *buf, size_t count)
8920 struct pmu *pmu = dev_get_drvdata(dev);
8921 int timer, cpu, ret;
8923 ret = kstrtoint(buf, 0, &timer);
8930 /* same value, noting to do */
8931 if (timer == pmu->hrtimer_interval_ms)
8934 mutex_lock(&mux_interval_mutex);
8935 pmu->hrtimer_interval_ms = timer;
8937 /* update all cpuctx for this PMU */
8939 for_each_online_cpu(cpu) {
8940 struct perf_cpu_context *cpuctx;
8941 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8942 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8944 cpu_function_call(cpu,
8945 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8948 mutex_unlock(&mux_interval_mutex);
8952 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8954 static struct attribute *pmu_dev_attrs[] = {
8955 &dev_attr_type.attr,
8956 &dev_attr_perf_event_mux_interval_ms.attr,
8959 ATTRIBUTE_GROUPS(pmu_dev);
8961 static int pmu_bus_running;
8962 static struct bus_type pmu_bus = {
8963 .name = "event_source",
8964 .dev_groups = pmu_dev_groups,
8967 static void pmu_dev_release(struct device *dev)
8972 static int pmu_dev_alloc(struct pmu *pmu)
8976 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8980 pmu->dev->groups = pmu->attr_groups;
8981 device_initialize(pmu->dev);
8982 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8986 dev_set_drvdata(pmu->dev, pmu);
8987 pmu->dev->bus = &pmu_bus;
8988 pmu->dev->release = pmu_dev_release;
8989 ret = device_add(pmu->dev);
8993 /* For PMUs with address filters, throw in an extra attribute: */
8994 if (pmu->nr_addr_filters)
8995 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9004 device_del(pmu->dev);
9007 put_device(pmu->dev);
9011 static struct lock_class_key cpuctx_mutex;
9012 static struct lock_class_key cpuctx_lock;
9014 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9018 mutex_lock(&pmus_lock);
9020 pmu->pmu_disable_count = alloc_percpu(int);
9021 if (!pmu->pmu_disable_count)
9030 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9038 if (pmu_bus_running) {
9039 ret = pmu_dev_alloc(pmu);
9045 if (pmu->task_ctx_nr == perf_hw_context) {
9046 static int hw_context_taken = 0;
9049 * Other than systems with heterogeneous CPUs, it never makes
9050 * sense for two PMUs to share perf_hw_context. PMUs which are
9051 * uncore must use perf_invalid_context.
9053 if (WARN_ON_ONCE(hw_context_taken &&
9054 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9055 pmu->task_ctx_nr = perf_invalid_context;
9057 hw_context_taken = 1;
9060 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9061 if (pmu->pmu_cpu_context)
9062 goto got_cpu_context;
9065 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9066 if (!pmu->pmu_cpu_context)
9069 for_each_possible_cpu(cpu) {
9070 struct perf_cpu_context *cpuctx;
9072 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9073 __perf_event_init_context(&cpuctx->ctx);
9074 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9075 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9076 cpuctx->ctx.pmu = pmu;
9077 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9079 __perf_mux_hrtimer_init(cpuctx, cpu);
9083 if (!pmu->start_txn) {
9084 if (pmu->pmu_enable) {
9086 * If we have pmu_enable/pmu_disable calls, install
9087 * transaction stubs that use that to try and batch
9088 * hardware accesses.
9090 pmu->start_txn = perf_pmu_start_txn;
9091 pmu->commit_txn = perf_pmu_commit_txn;
9092 pmu->cancel_txn = perf_pmu_cancel_txn;
9094 pmu->start_txn = perf_pmu_nop_txn;
9095 pmu->commit_txn = perf_pmu_nop_int;
9096 pmu->cancel_txn = perf_pmu_nop_void;
9100 if (!pmu->pmu_enable) {
9101 pmu->pmu_enable = perf_pmu_nop_void;
9102 pmu->pmu_disable = perf_pmu_nop_void;
9105 if (!pmu->event_idx)
9106 pmu->event_idx = perf_event_idx_default;
9108 list_add_rcu(&pmu->entry, &pmus);
9109 atomic_set(&pmu->exclusive_cnt, 0);
9112 mutex_unlock(&pmus_lock);
9117 device_del(pmu->dev);
9118 put_device(pmu->dev);
9121 if (pmu->type >= PERF_TYPE_MAX)
9122 idr_remove(&pmu_idr, pmu->type);
9125 free_percpu(pmu->pmu_disable_count);
9128 EXPORT_SYMBOL_GPL(perf_pmu_register);
9130 void perf_pmu_unregister(struct pmu *pmu)
9134 mutex_lock(&pmus_lock);
9135 remove_device = pmu_bus_running;
9136 list_del_rcu(&pmu->entry);
9137 mutex_unlock(&pmus_lock);
9140 * We dereference the pmu list under both SRCU and regular RCU, so
9141 * synchronize against both of those.
9143 synchronize_srcu(&pmus_srcu);
9146 free_percpu(pmu->pmu_disable_count);
9147 if (pmu->type >= PERF_TYPE_MAX)
9148 idr_remove(&pmu_idr, pmu->type);
9149 if (remove_device) {
9150 if (pmu->nr_addr_filters)
9151 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9152 device_del(pmu->dev);
9153 put_device(pmu->dev);
9155 free_pmu_context(pmu);
9157 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9159 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9161 struct perf_event_context *ctx = NULL;
9164 if (!try_module_get(pmu->module))
9167 if (event->group_leader != event) {
9169 * This ctx->mutex can nest when we're called through
9170 * inheritance. See the perf_event_ctx_lock_nested() comment.
9172 ctx = perf_event_ctx_lock_nested(event->group_leader,
9173 SINGLE_DEPTH_NESTING);
9178 ret = pmu->event_init(event);
9181 perf_event_ctx_unlock(event->group_leader, ctx);
9184 module_put(pmu->module);
9189 static struct pmu *perf_init_event(struct perf_event *event)
9195 idx = srcu_read_lock(&pmus_srcu);
9197 /* Try parent's PMU first: */
9198 if (event->parent && event->parent->pmu) {
9199 pmu = event->parent->pmu;
9200 ret = perf_try_init_event(pmu, event);
9206 pmu = idr_find(&pmu_idr, event->attr.type);
9209 ret = perf_try_init_event(pmu, event);
9215 list_for_each_entry_rcu(pmu, &pmus, entry) {
9216 ret = perf_try_init_event(pmu, event);
9220 if (ret != -ENOENT) {
9225 pmu = ERR_PTR(-ENOENT);
9227 srcu_read_unlock(&pmus_srcu, idx);
9232 static void attach_sb_event(struct perf_event *event)
9234 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9236 raw_spin_lock(&pel->lock);
9237 list_add_rcu(&event->sb_list, &pel->list);
9238 raw_spin_unlock(&pel->lock);
9242 * We keep a list of all !task (and therefore per-cpu) events
9243 * that need to receive side-band records.
9245 * This avoids having to scan all the various PMU per-cpu contexts
9248 static void account_pmu_sb_event(struct perf_event *event)
9250 if (is_sb_event(event))
9251 attach_sb_event(event);
9254 static void account_event_cpu(struct perf_event *event, int cpu)
9259 if (is_cgroup_event(event))
9260 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9263 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9264 static void account_freq_event_nohz(void)
9266 #ifdef CONFIG_NO_HZ_FULL
9267 /* Lock so we don't race with concurrent unaccount */
9268 spin_lock(&nr_freq_lock);
9269 if (atomic_inc_return(&nr_freq_events) == 1)
9270 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9271 spin_unlock(&nr_freq_lock);
9275 static void account_freq_event(void)
9277 if (tick_nohz_full_enabled())
9278 account_freq_event_nohz();
9280 atomic_inc(&nr_freq_events);
9284 static void account_event(struct perf_event *event)
9291 if (event->attach_state & PERF_ATTACH_TASK)
9293 if (event->attr.mmap || event->attr.mmap_data)
9294 atomic_inc(&nr_mmap_events);
9295 if (event->attr.comm)
9296 atomic_inc(&nr_comm_events);
9297 if (event->attr.namespaces)
9298 atomic_inc(&nr_namespaces_events);
9299 if (event->attr.task)
9300 atomic_inc(&nr_task_events);
9301 if (event->attr.freq)
9302 account_freq_event();
9303 if (event->attr.context_switch) {
9304 atomic_inc(&nr_switch_events);
9307 if (has_branch_stack(event))
9309 if (is_cgroup_event(event))
9314 * We need the mutex here because static_branch_enable()
9315 * must complete *before* the perf_sched_count increment
9318 if (atomic_inc_not_zero(&perf_sched_count))
9321 mutex_lock(&perf_sched_mutex);
9322 if (!atomic_read(&perf_sched_count)) {
9323 static_branch_enable(&perf_sched_events);
9325 * Guarantee that all CPUs observe they key change and
9326 * call the perf scheduling hooks before proceeding to
9327 * install events that need them.
9329 synchronize_sched();
9332 * Now that we have waited for the sync_sched(), allow further
9333 * increments to by-pass the mutex.
9335 atomic_inc(&perf_sched_count);
9336 mutex_unlock(&perf_sched_mutex);
9340 account_event_cpu(event, event->cpu);
9342 account_pmu_sb_event(event);
9346 * Allocate and initialize a event structure
9348 static struct perf_event *
9349 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9350 struct task_struct *task,
9351 struct perf_event *group_leader,
9352 struct perf_event *parent_event,
9353 perf_overflow_handler_t overflow_handler,
9354 void *context, int cgroup_fd)
9357 struct perf_event *event;
9358 struct hw_perf_event *hwc;
9361 if ((unsigned)cpu >= nr_cpu_ids) {
9362 if (!task || cpu != -1)
9363 return ERR_PTR(-EINVAL);
9366 event = kzalloc(sizeof(*event), GFP_KERNEL);
9368 return ERR_PTR(-ENOMEM);
9371 * Single events are their own group leaders, with an
9372 * empty sibling list:
9375 group_leader = event;
9377 mutex_init(&event->child_mutex);
9378 INIT_LIST_HEAD(&event->child_list);
9380 INIT_LIST_HEAD(&event->group_entry);
9381 INIT_LIST_HEAD(&event->event_entry);
9382 INIT_LIST_HEAD(&event->sibling_list);
9383 INIT_LIST_HEAD(&event->rb_entry);
9384 INIT_LIST_HEAD(&event->active_entry);
9385 INIT_LIST_HEAD(&event->addr_filters.list);
9386 INIT_HLIST_NODE(&event->hlist_entry);
9389 init_waitqueue_head(&event->waitq);
9390 init_irq_work(&event->pending, perf_pending_event);
9392 mutex_init(&event->mmap_mutex);
9393 raw_spin_lock_init(&event->addr_filters.lock);
9395 atomic_long_set(&event->refcount, 1);
9397 event->attr = *attr;
9398 event->group_leader = group_leader;
9402 event->parent = parent_event;
9404 event->ns = get_pid_ns(task_active_pid_ns(current));
9405 event->id = atomic64_inc_return(&perf_event_id);
9407 event->state = PERF_EVENT_STATE_INACTIVE;
9410 event->attach_state = PERF_ATTACH_TASK;
9412 * XXX pmu::event_init needs to know what task to account to
9413 * and we cannot use the ctx information because we need the
9414 * pmu before we get a ctx.
9416 event->hw.target = task;
9419 event->clock = &local_clock;
9421 event->clock = parent_event->clock;
9423 if (!overflow_handler && parent_event) {
9424 overflow_handler = parent_event->overflow_handler;
9425 context = parent_event->overflow_handler_context;
9426 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9427 if (overflow_handler == bpf_overflow_handler) {
9428 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9431 err = PTR_ERR(prog);
9435 event->orig_overflow_handler =
9436 parent_event->orig_overflow_handler;
9441 if (overflow_handler) {
9442 event->overflow_handler = overflow_handler;
9443 event->overflow_handler_context = context;
9444 } else if (is_write_backward(event)){
9445 event->overflow_handler = perf_event_output_backward;
9446 event->overflow_handler_context = NULL;
9448 event->overflow_handler = perf_event_output_forward;
9449 event->overflow_handler_context = NULL;
9452 perf_event__state_init(event);
9457 hwc->sample_period = attr->sample_period;
9458 if (attr->freq && attr->sample_freq)
9459 hwc->sample_period = 1;
9460 hwc->last_period = hwc->sample_period;
9462 local64_set(&hwc->period_left, hwc->sample_period);
9465 * We currently do not support PERF_SAMPLE_READ on inherited events.
9466 * See perf_output_read().
9468 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9471 if (!has_branch_stack(event))
9472 event->attr.branch_sample_type = 0;
9474 if (cgroup_fd != -1) {
9475 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9480 pmu = perf_init_event(event);
9486 err = exclusive_event_init(event);
9490 if (has_addr_filter(event)) {
9491 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9492 sizeof(unsigned long),
9494 if (!event->addr_filters_offs) {
9499 /* force hw sync on the address filters */
9500 event->addr_filters_gen = 1;
9503 if (!event->parent) {
9504 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9505 err = get_callchain_buffers(attr->sample_max_stack);
9507 goto err_addr_filters;
9511 /* symmetric to unaccount_event() in _free_event() */
9512 account_event(event);
9517 kfree(event->addr_filters_offs);
9520 exclusive_event_destroy(event);
9524 event->destroy(event);
9525 module_put(pmu->module);
9527 if (is_cgroup_event(event))
9528 perf_detach_cgroup(event);
9530 put_pid_ns(event->ns);
9533 return ERR_PTR(err);
9536 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9537 struct perf_event_attr *attr)
9542 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9546 * zero the full structure, so that a short copy will be nice.
9548 memset(attr, 0, sizeof(*attr));
9550 ret = get_user(size, &uattr->size);
9554 if (size > PAGE_SIZE) /* silly large */
9557 if (!size) /* abi compat */
9558 size = PERF_ATTR_SIZE_VER0;
9560 if (size < PERF_ATTR_SIZE_VER0)
9564 * If we're handed a bigger struct than we know of,
9565 * ensure all the unknown bits are 0 - i.e. new
9566 * user-space does not rely on any kernel feature
9567 * extensions we dont know about yet.
9569 if (size > sizeof(*attr)) {
9570 unsigned char __user *addr;
9571 unsigned char __user *end;
9574 addr = (void __user *)uattr + sizeof(*attr);
9575 end = (void __user *)uattr + size;
9577 for (; addr < end; addr++) {
9578 ret = get_user(val, addr);
9584 size = sizeof(*attr);
9587 ret = copy_from_user(attr, uattr, size);
9593 if (attr->__reserved_1)
9596 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9599 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9602 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9603 u64 mask = attr->branch_sample_type;
9605 /* only using defined bits */
9606 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9609 /* at least one branch bit must be set */
9610 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9613 /* propagate priv level, when not set for branch */
9614 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9616 /* exclude_kernel checked on syscall entry */
9617 if (!attr->exclude_kernel)
9618 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9620 if (!attr->exclude_user)
9621 mask |= PERF_SAMPLE_BRANCH_USER;
9623 if (!attr->exclude_hv)
9624 mask |= PERF_SAMPLE_BRANCH_HV;
9626 * adjust user setting (for HW filter setup)
9628 attr->branch_sample_type = mask;
9630 /* privileged levels capture (kernel, hv): check permissions */
9631 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9632 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9636 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9637 ret = perf_reg_validate(attr->sample_regs_user);
9642 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9643 if (!arch_perf_have_user_stack_dump())
9647 * We have __u32 type for the size, but so far
9648 * we can only use __u16 as maximum due to the
9649 * __u16 sample size limit.
9651 if (attr->sample_stack_user >= USHRT_MAX)
9653 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9657 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9658 ret = perf_reg_validate(attr->sample_regs_intr);
9663 put_user(sizeof(*attr), &uattr->size);
9669 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9671 struct ring_buffer *rb = NULL;
9677 /* don't allow circular references */
9678 if (event == output_event)
9682 * Don't allow cross-cpu buffers
9684 if (output_event->cpu != event->cpu)
9688 * If its not a per-cpu rb, it must be the same task.
9690 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9694 * Mixing clocks in the same buffer is trouble you don't need.
9696 if (output_event->clock != event->clock)
9700 * Either writing ring buffer from beginning or from end.
9701 * Mixing is not allowed.
9703 if (is_write_backward(output_event) != is_write_backward(event))
9707 * If both events generate aux data, they must be on the same PMU
9709 if (has_aux(event) && has_aux(output_event) &&
9710 event->pmu != output_event->pmu)
9714 mutex_lock(&event->mmap_mutex);
9715 /* Can't redirect output if we've got an active mmap() */
9716 if (atomic_read(&event->mmap_count))
9720 /* get the rb we want to redirect to */
9721 rb = ring_buffer_get(output_event);
9726 ring_buffer_attach(event, rb);
9730 mutex_unlock(&event->mmap_mutex);
9736 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9742 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9745 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9747 bool nmi_safe = false;
9750 case CLOCK_MONOTONIC:
9751 event->clock = &ktime_get_mono_fast_ns;
9755 case CLOCK_MONOTONIC_RAW:
9756 event->clock = &ktime_get_raw_fast_ns;
9760 case CLOCK_REALTIME:
9761 event->clock = &ktime_get_real_ns;
9764 case CLOCK_BOOTTIME:
9765 event->clock = &ktime_get_boot_ns;
9769 event->clock = &ktime_get_tai_ns;
9776 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9783 * Variation on perf_event_ctx_lock_nested(), except we take two context
9786 static struct perf_event_context *
9787 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9788 struct perf_event_context *ctx)
9790 struct perf_event_context *gctx;
9794 gctx = READ_ONCE(group_leader->ctx);
9795 if (!atomic_inc_not_zero(&gctx->refcount)) {
9801 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9803 if (group_leader->ctx != gctx) {
9804 mutex_unlock(&ctx->mutex);
9805 mutex_unlock(&gctx->mutex);
9814 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9816 * @attr_uptr: event_id type attributes for monitoring/sampling
9819 * @group_fd: group leader event fd
9821 SYSCALL_DEFINE5(perf_event_open,
9822 struct perf_event_attr __user *, attr_uptr,
9823 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9825 struct perf_event *group_leader = NULL, *output_event = NULL;
9826 struct perf_event *event, *sibling;
9827 struct perf_event_attr attr;
9828 struct perf_event_context *ctx, *uninitialized_var(gctx);
9829 struct file *event_file = NULL;
9830 struct fd group = {NULL, 0};
9831 struct task_struct *task = NULL;
9836 int f_flags = O_RDWR;
9839 /* for future expandability... */
9840 if (flags & ~PERF_FLAG_ALL)
9843 err = perf_copy_attr(attr_uptr, &attr);
9847 if (!attr.exclude_kernel) {
9848 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9852 if (attr.namespaces) {
9853 if (!capable(CAP_SYS_ADMIN))
9858 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9861 if (attr.sample_period & (1ULL << 63))
9865 /* Only privileged users can get physical addresses */
9866 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
9867 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9870 if (!attr.sample_max_stack)
9871 attr.sample_max_stack = sysctl_perf_event_max_stack;
9874 * In cgroup mode, the pid argument is used to pass the fd
9875 * opened to the cgroup directory in cgroupfs. The cpu argument
9876 * designates the cpu on which to monitor threads from that
9879 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9882 if (flags & PERF_FLAG_FD_CLOEXEC)
9883 f_flags |= O_CLOEXEC;
9885 event_fd = get_unused_fd_flags(f_flags);
9889 if (group_fd != -1) {
9890 err = perf_fget_light(group_fd, &group);
9893 group_leader = group.file->private_data;
9894 if (flags & PERF_FLAG_FD_OUTPUT)
9895 output_event = group_leader;
9896 if (flags & PERF_FLAG_FD_NO_GROUP)
9897 group_leader = NULL;
9900 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9901 task = find_lively_task_by_vpid(pid);
9903 err = PTR_ERR(task);
9908 if (task && group_leader &&
9909 group_leader->attr.inherit != attr.inherit) {
9915 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9920 * Reuse ptrace permission checks for now.
9922 * We must hold cred_guard_mutex across this and any potential
9923 * perf_install_in_context() call for this new event to
9924 * serialize against exec() altering our credentials (and the
9925 * perf_event_exit_task() that could imply).
9928 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9932 if (flags & PERF_FLAG_PID_CGROUP)
9935 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9936 NULL, NULL, cgroup_fd);
9937 if (IS_ERR(event)) {
9938 err = PTR_ERR(event);
9942 if (is_sampling_event(event)) {
9943 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9950 * Special case software events and allow them to be part of
9951 * any hardware group.
9955 if (attr.use_clockid) {
9956 err = perf_event_set_clock(event, attr.clockid);
9961 if (pmu->task_ctx_nr == perf_sw_context)
9962 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9965 (is_software_event(event) != is_software_event(group_leader))) {
9966 if (is_software_event(event)) {
9968 * If event and group_leader are not both a software
9969 * event, and event is, then group leader is not.
9971 * Allow the addition of software events to !software
9972 * groups, this is safe because software events never
9975 pmu = group_leader->pmu;
9976 } else if (is_software_event(group_leader) &&
9977 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9979 * In case the group is a pure software group, and we
9980 * try to add a hardware event, move the whole group to
9981 * the hardware context.
9988 * Get the target context (task or percpu):
9990 ctx = find_get_context(pmu, task, event);
9996 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10002 * Look up the group leader (we will attach this event to it):
10004 if (group_leader) {
10008 * Do not allow a recursive hierarchy (this new sibling
10009 * becoming part of another group-sibling):
10011 if (group_leader->group_leader != group_leader)
10014 /* All events in a group should have the same clock */
10015 if (group_leader->clock != event->clock)
10019 * Make sure we're both events for the same CPU;
10020 * grouping events for different CPUs is broken; since
10021 * you can never concurrently schedule them anyhow.
10023 if (group_leader->cpu != event->cpu)
10027 * Make sure we're both on the same task, or both
10030 if (group_leader->ctx->task != ctx->task)
10034 * Do not allow to attach to a group in a different task
10035 * or CPU context. If we're moving SW events, we'll fix
10036 * this up later, so allow that.
10038 if (!move_group && group_leader->ctx != ctx)
10042 * Only a group leader can be exclusive or pinned
10044 if (attr.exclusive || attr.pinned)
10048 if (output_event) {
10049 err = perf_event_set_output(event, output_event);
10054 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10056 if (IS_ERR(event_file)) {
10057 err = PTR_ERR(event_file);
10063 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10065 if (gctx->task == TASK_TOMBSTONE) {
10071 * Check if we raced against another sys_perf_event_open() call
10072 * moving the software group underneath us.
10074 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10076 * If someone moved the group out from under us, check
10077 * if this new event wound up on the same ctx, if so
10078 * its the regular !move_group case, otherwise fail.
10084 perf_event_ctx_unlock(group_leader, gctx);
10089 mutex_lock(&ctx->mutex);
10092 if (ctx->task == TASK_TOMBSTONE) {
10097 if (!perf_event_validate_size(event)) {
10104 * Check if the @cpu we're creating an event for is online.
10106 * We use the perf_cpu_context::ctx::mutex to serialize against
10107 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10109 struct perf_cpu_context *cpuctx =
10110 container_of(ctx, struct perf_cpu_context, ctx);
10112 if (!cpuctx->online) {
10120 * Must be under the same ctx::mutex as perf_install_in_context(),
10121 * because we need to serialize with concurrent event creation.
10123 if (!exclusive_event_installable(event, ctx)) {
10124 /* exclusive and group stuff are assumed mutually exclusive */
10125 WARN_ON_ONCE(move_group);
10131 WARN_ON_ONCE(ctx->parent_ctx);
10134 * This is the point on no return; we cannot fail hereafter. This is
10135 * where we start modifying current state.
10140 * See perf_event_ctx_lock() for comments on the details
10141 * of swizzling perf_event::ctx.
10143 perf_remove_from_context(group_leader, 0);
10146 list_for_each_entry(sibling, &group_leader->sibling_list,
10148 perf_remove_from_context(sibling, 0);
10153 * Wait for everybody to stop referencing the events through
10154 * the old lists, before installing it on new lists.
10159 * Install the group siblings before the group leader.
10161 * Because a group leader will try and install the entire group
10162 * (through the sibling list, which is still in-tact), we can
10163 * end up with siblings installed in the wrong context.
10165 * By installing siblings first we NO-OP because they're not
10166 * reachable through the group lists.
10168 list_for_each_entry(sibling, &group_leader->sibling_list,
10170 perf_event__state_init(sibling);
10171 perf_install_in_context(ctx, sibling, sibling->cpu);
10176 * Removing from the context ends up with disabled
10177 * event. What we want here is event in the initial
10178 * startup state, ready to be add into new context.
10180 perf_event__state_init(group_leader);
10181 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10186 * Precalculate sample_data sizes; do while holding ctx::mutex such
10187 * that we're serialized against further additions and before
10188 * perf_install_in_context() which is the point the event is active and
10189 * can use these values.
10191 perf_event__header_size(event);
10192 perf_event__id_header_size(event);
10194 event->owner = current;
10196 perf_install_in_context(ctx, event, event->cpu);
10197 perf_unpin_context(ctx);
10200 perf_event_ctx_unlock(group_leader, gctx);
10201 mutex_unlock(&ctx->mutex);
10204 mutex_unlock(&task->signal->cred_guard_mutex);
10205 put_task_struct(task);
10208 mutex_lock(¤t->perf_event_mutex);
10209 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10210 mutex_unlock(¤t->perf_event_mutex);
10213 * Drop the reference on the group_event after placing the
10214 * new event on the sibling_list. This ensures destruction
10215 * of the group leader will find the pointer to itself in
10216 * perf_group_detach().
10219 fd_install(event_fd, event_file);
10224 perf_event_ctx_unlock(group_leader, gctx);
10225 mutex_unlock(&ctx->mutex);
10229 perf_unpin_context(ctx);
10233 * If event_file is set, the fput() above will have called ->release()
10234 * and that will take care of freeing the event.
10240 mutex_unlock(&task->signal->cred_guard_mutex);
10243 put_task_struct(task);
10247 put_unused_fd(event_fd);
10252 * perf_event_create_kernel_counter
10254 * @attr: attributes of the counter to create
10255 * @cpu: cpu in which the counter is bound
10256 * @task: task to profile (NULL for percpu)
10258 struct perf_event *
10259 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10260 struct task_struct *task,
10261 perf_overflow_handler_t overflow_handler,
10264 struct perf_event_context *ctx;
10265 struct perf_event *event;
10269 * Get the target context (task or percpu):
10272 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10273 overflow_handler, context, -1);
10274 if (IS_ERR(event)) {
10275 err = PTR_ERR(event);
10279 /* Mark owner so we could distinguish it from user events. */
10280 event->owner = TASK_TOMBSTONE;
10282 ctx = find_get_context(event->pmu, task, event);
10284 err = PTR_ERR(ctx);
10288 WARN_ON_ONCE(ctx->parent_ctx);
10289 mutex_lock(&ctx->mutex);
10290 if (ctx->task == TASK_TOMBSTONE) {
10297 * Check if the @cpu we're creating an event for is online.
10299 * We use the perf_cpu_context::ctx::mutex to serialize against
10300 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10302 struct perf_cpu_context *cpuctx =
10303 container_of(ctx, struct perf_cpu_context, ctx);
10304 if (!cpuctx->online) {
10310 if (!exclusive_event_installable(event, ctx)) {
10315 perf_install_in_context(ctx, event, cpu);
10316 perf_unpin_context(ctx);
10317 mutex_unlock(&ctx->mutex);
10322 mutex_unlock(&ctx->mutex);
10323 perf_unpin_context(ctx);
10328 return ERR_PTR(err);
10330 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10332 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10334 struct perf_event_context *src_ctx;
10335 struct perf_event_context *dst_ctx;
10336 struct perf_event *event, *tmp;
10339 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10340 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10343 * See perf_event_ctx_lock() for comments on the details
10344 * of swizzling perf_event::ctx.
10346 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10347 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10349 perf_remove_from_context(event, 0);
10350 unaccount_event_cpu(event, src_cpu);
10352 list_add(&event->migrate_entry, &events);
10356 * Wait for the events to quiesce before re-instating them.
10361 * Re-instate events in 2 passes.
10363 * Skip over group leaders and only install siblings on this first
10364 * pass, siblings will not get enabled without a leader, however a
10365 * leader will enable its siblings, even if those are still on the old
10368 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10369 if (event->group_leader == event)
10372 list_del(&event->migrate_entry);
10373 if (event->state >= PERF_EVENT_STATE_OFF)
10374 event->state = PERF_EVENT_STATE_INACTIVE;
10375 account_event_cpu(event, dst_cpu);
10376 perf_install_in_context(dst_ctx, event, dst_cpu);
10381 * Once all the siblings are setup properly, install the group leaders
10384 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10385 list_del(&event->migrate_entry);
10386 if (event->state >= PERF_EVENT_STATE_OFF)
10387 event->state = PERF_EVENT_STATE_INACTIVE;
10388 account_event_cpu(event, dst_cpu);
10389 perf_install_in_context(dst_ctx, event, dst_cpu);
10392 mutex_unlock(&dst_ctx->mutex);
10393 mutex_unlock(&src_ctx->mutex);
10395 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10397 static void sync_child_event(struct perf_event *child_event,
10398 struct task_struct *child)
10400 struct perf_event *parent_event = child_event->parent;
10403 if (child_event->attr.inherit_stat)
10404 perf_event_read_event(child_event, child);
10406 child_val = perf_event_count(child_event);
10409 * Add back the child's count to the parent's count:
10411 atomic64_add(child_val, &parent_event->child_count);
10412 atomic64_add(child_event->total_time_enabled,
10413 &parent_event->child_total_time_enabled);
10414 atomic64_add(child_event->total_time_running,
10415 &parent_event->child_total_time_running);
10419 perf_event_exit_event(struct perf_event *child_event,
10420 struct perf_event_context *child_ctx,
10421 struct task_struct *child)
10423 struct perf_event *parent_event = child_event->parent;
10426 * Do not destroy the 'original' grouping; because of the context
10427 * switch optimization the original events could've ended up in a
10428 * random child task.
10430 * If we were to destroy the original group, all group related
10431 * operations would cease to function properly after this random
10434 * Do destroy all inherited groups, we don't care about those
10435 * and being thorough is better.
10437 raw_spin_lock_irq(&child_ctx->lock);
10438 WARN_ON_ONCE(child_ctx->is_active);
10441 perf_group_detach(child_event);
10442 list_del_event(child_event, child_ctx);
10443 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
10444 raw_spin_unlock_irq(&child_ctx->lock);
10447 * Parent events are governed by their filedesc, retain them.
10449 if (!parent_event) {
10450 perf_event_wakeup(child_event);
10454 * Child events can be cleaned up.
10457 sync_child_event(child_event, child);
10460 * Remove this event from the parent's list
10462 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10463 mutex_lock(&parent_event->child_mutex);
10464 list_del_init(&child_event->child_list);
10465 mutex_unlock(&parent_event->child_mutex);
10468 * Kick perf_poll() for is_event_hup().
10470 perf_event_wakeup(parent_event);
10471 free_event(child_event);
10472 put_event(parent_event);
10475 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10477 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10478 struct perf_event *child_event, *next;
10480 WARN_ON_ONCE(child != current);
10482 child_ctx = perf_pin_task_context(child, ctxn);
10487 * In order to reduce the amount of tricky in ctx tear-down, we hold
10488 * ctx::mutex over the entire thing. This serializes against almost
10489 * everything that wants to access the ctx.
10491 * The exception is sys_perf_event_open() /
10492 * perf_event_create_kernel_count() which does find_get_context()
10493 * without ctx::mutex (it cannot because of the move_group double mutex
10494 * lock thing). See the comments in perf_install_in_context().
10496 mutex_lock(&child_ctx->mutex);
10499 * In a single ctx::lock section, de-schedule the events and detach the
10500 * context from the task such that we cannot ever get it scheduled back
10503 raw_spin_lock_irq(&child_ctx->lock);
10504 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10507 * Now that the context is inactive, destroy the task <-> ctx relation
10508 * and mark the context dead.
10510 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10511 put_ctx(child_ctx); /* cannot be last */
10512 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10513 put_task_struct(current); /* cannot be last */
10515 clone_ctx = unclone_ctx(child_ctx);
10516 raw_spin_unlock_irq(&child_ctx->lock);
10519 put_ctx(clone_ctx);
10522 * Report the task dead after unscheduling the events so that we
10523 * won't get any samples after PERF_RECORD_EXIT. We can however still
10524 * get a few PERF_RECORD_READ events.
10526 perf_event_task(child, child_ctx, 0);
10528 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10529 perf_event_exit_event(child_event, child_ctx, child);
10531 mutex_unlock(&child_ctx->mutex);
10533 put_ctx(child_ctx);
10537 * When a child task exits, feed back event values to parent events.
10539 * Can be called with cred_guard_mutex held when called from
10540 * install_exec_creds().
10542 void perf_event_exit_task(struct task_struct *child)
10544 struct perf_event *event, *tmp;
10547 mutex_lock(&child->perf_event_mutex);
10548 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10550 list_del_init(&event->owner_entry);
10553 * Ensure the list deletion is visible before we clear
10554 * the owner, closes a race against perf_release() where
10555 * we need to serialize on the owner->perf_event_mutex.
10557 smp_store_release(&event->owner, NULL);
10559 mutex_unlock(&child->perf_event_mutex);
10561 for_each_task_context_nr(ctxn)
10562 perf_event_exit_task_context(child, ctxn);
10565 * The perf_event_exit_task_context calls perf_event_task
10566 * with child's task_ctx, which generates EXIT events for
10567 * child contexts and sets child->perf_event_ctxp[] to NULL.
10568 * At this point we need to send EXIT events to cpu contexts.
10570 perf_event_task(child, NULL, 0);
10573 static void perf_free_event(struct perf_event *event,
10574 struct perf_event_context *ctx)
10576 struct perf_event *parent = event->parent;
10578 if (WARN_ON_ONCE(!parent))
10581 mutex_lock(&parent->child_mutex);
10582 list_del_init(&event->child_list);
10583 mutex_unlock(&parent->child_mutex);
10587 raw_spin_lock_irq(&ctx->lock);
10588 perf_group_detach(event);
10589 list_del_event(event, ctx);
10590 raw_spin_unlock_irq(&ctx->lock);
10595 * Free an unexposed, unused context as created by inheritance by
10596 * perf_event_init_task below, used by fork() in case of fail.
10598 * Not all locks are strictly required, but take them anyway to be nice and
10599 * help out with the lockdep assertions.
10601 void perf_event_free_task(struct task_struct *task)
10603 struct perf_event_context *ctx;
10604 struct perf_event *event, *tmp;
10607 for_each_task_context_nr(ctxn) {
10608 ctx = task->perf_event_ctxp[ctxn];
10612 mutex_lock(&ctx->mutex);
10613 raw_spin_lock_irq(&ctx->lock);
10615 * Destroy the task <-> ctx relation and mark the context dead.
10617 * This is important because even though the task hasn't been
10618 * exposed yet the context has been (through child_list).
10620 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10621 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10622 put_task_struct(task); /* cannot be last */
10623 raw_spin_unlock_irq(&ctx->lock);
10625 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10626 perf_free_event(event, ctx);
10628 mutex_unlock(&ctx->mutex);
10633 void perf_event_delayed_put(struct task_struct *task)
10637 for_each_task_context_nr(ctxn)
10638 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10641 struct file *perf_event_get(unsigned int fd)
10645 file = fget_raw(fd);
10647 return ERR_PTR(-EBADF);
10649 if (file->f_op != &perf_fops) {
10651 return ERR_PTR(-EBADF);
10657 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10660 return ERR_PTR(-EINVAL);
10662 return &event->attr;
10666 * Inherit a event from parent task to child task.
10669 * - valid pointer on success
10670 * - NULL for orphaned events
10671 * - IS_ERR() on error
10673 static struct perf_event *
10674 inherit_event(struct perf_event *parent_event,
10675 struct task_struct *parent,
10676 struct perf_event_context *parent_ctx,
10677 struct task_struct *child,
10678 struct perf_event *group_leader,
10679 struct perf_event_context *child_ctx)
10681 enum perf_event_state parent_state = parent_event->state;
10682 struct perf_event *child_event;
10683 unsigned long flags;
10686 * Instead of creating recursive hierarchies of events,
10687 * we link inherited events back to the original parent,
10688 * which has a filp for sure, which we use as the reference
10691 if (parent_event->parent)
10692 parent_event = parent_event->parent;
10694 child_event = perf_event_alloc(&parent_event->attr,
10697 group_leader, parent_event,
10699 if (IS_ERR(child_event))
10700 return child_event;
10703 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10704 * must be under the same lock in order to serialize against
10705 * perf_event_release_kernel(), such that either we must observe
10706 * is_orphaned_event() or they will observe us on the child_list.
10708 mutex_lock(&parent_event->child_mutex);
10709 if (is_orphaned_event(parent_event) ||
10710 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10711 mutex_unlock(&parent_event->child_mutex);
10712 free_event(child_event);
10716 get_ctx(child_ctx);
10719 * Make the child state follow the state of the parent event,
10720 * not its attr.disabled bit. We hold the parent's mutex,
10721 * so we won't race with perf_event_{en, dis}able_family.
10723 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10724 child_event->state = PERF_EVENT_STATE_INACTIVE;
10726 child_event->state = PERF_EVENT_STATE_OFF;
10728 if (parent_event->attr.freq) {
10729 u64 sample_period = parent_event->hw.sample_period;
10730 struct hw_perf_event *hwc = &child_event->hw;
10732 hwc->sample_period = sample_period;
10733 hwc->last_period = sample_period;
10735 local64_set(&hwc->period_left, sample_period);
10738 child_event->ctx = child_ctx;
10739 child_event->overflow_handler = parent_event->overflow_handler;
10740 child_event->overflow_handler_context
10741 = parent_event->overflow_handler_context;
10744 * Precalculate sample_data sizes
10746 perf_event__header_size(child_event);
10747 perf_event__id_header_size(child_event);
10750 * Link it up in the child's context:
10752 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10753 add_event_to_ctx(child_event, child_ctx);
10754 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10757 * Link this into the parent event's child list
10759 list_add_tail(&child_event->child_list, &parent_event->child_list);
10760 mutex_unlock(&parent_event->child_mutex);
10762 return child_event;
10766 * Inherits an event group.
10768 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10769 * This matches with perf_event_release_kernel() removing all child events.
10775 static int inherit_group(struct perf_event *parent_event,
10776 struct task_struct *parent,
10777 struct perf_event_context *parent_ctx,
10778 struct task_struct *child,
10779 struct perf_event_context *child_ctx)
10781 struct perf_event *leader;
10782 struct perf_event *sub;
10783 struct perf_event *child_ctr;
10785 leader = inherit_event(parent_event, parent, parent_ctx,
10786 child, NULL, child_ctx);
10787 if (IS_ERR(leader))
10788 return PTR_ERR(leader);
10790 * @leader can be NULL here because of is_orphaned_event(). In this
10791 * case inherit_event() will create individual events, similar to what
10792 * perf_group_detach() would do anyway.
10794 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10795 child_ctr = inherit_event(sub, parent, parent_ctx,
10796 child, leader, child_ctx);
10797 if (IS_ERR(child_ctr))
10798 return PTR_ERR(child_ctr);
10804 * Creates the child task context and tries to inherit the event-group.
10806 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10807 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10808 * consistent with perf_event_release_kernel() removing all child events.
10815 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10816 struct perf_event_context *parent_ctx,
10817 struct task_struct *child, int ctxn,
10818 int *inherited_all)
10821 struct perf_event_context *child_ctx;
10823 if (!event->attr.inherit) {
10824 *inherited_all = 0;
10828 child_ctx = child->perf_event_ctxp[ctxn];
10831 * This is executed from the parent task context, so
10832 * inherit events that have been marked for cloning.
10833 * First allocate and initialize a context for the
10836 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10840 child->perf_event_ctxp[ctxn] = child_ctx;
10843 ret = inherit_group(event, parent, parent_ctx,
10847 *inherited_all = 0;
10853 * Initialize the perf_event context in task_struct
10855 static int perf_event_init_context(struct task_struct *child, int ctxn)
10857 struct perf_event_context *child_ctx, *parent_ctx;
10858 struct perf_event_context *cloned_ctx;
10859 struct perf_event *event;
10860 struct task_struct *parent = current;
10861 int inherited_all = 1;
10862 unsigned long flags;
10865 if (likely(!parent->perf_event_ctxp[ctxn]))
10869 * If the parent's context is a clone, pin it so it won't get
10870 * swapped under us.
10872 parent_ctx = perf_pin_task_context(parent, ctxn);
10877 * No need to check if parent_ctx != NULL here; since we saw
10878 * it non-NULL earlier, the only reason for it to become NULL
10879 * is if we exit, and since we're currently in the middle of
10880 * a fork we can't be exiting at the same time.
10884 * Lock the parent list. No need to lock the child - not PID
10885 * hashed yet and not running, so nobody can access it.
10887 mutex_lock(&parent_ctx->mutex);
10890 * We dont have to disable NMIs - we are only looking at
10891 * the list, not manipulating it:
10893 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10894 ret = inherit_task_group(event, parent, parent_ctx,
10895 child, ctxn, &inherited_all);
10901 * We can't hold ctx->lock when iterating the ->flexible_group list due
10902 * to allocations, but we need to prevent rotation because
10903 * rotate_ctx() will change the list from interrupt context.
10905 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10906 parent_ctx->rotate_disable = 1;
10907 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10909 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10910 ret = inherit_task_group(event, parent, parent_ctx,
10911 child, ctxn, &inherited_all);
10916 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10917 parent_ctx->rotate_disable = 0;
10919 child_ctx = child->perf_event_ctxp[ctxn];
10921 if (child_ctx && inherited_all) {
10923 * Mark the child context as a clone of the parent
10924 * context, or of whatever the parent is a clone of.
10926 * Note that if the parent is a clone, the holding of
10927 * parent_ctx->lock avoids it from being uncloned.
10929 cloned_ctx = parent_ctx->parent_ctx;
10931 child_ctx->parent_ctx = cloned_ctx;
10932 child_ctx->parent_gen = parent_ctx->parent_gen;
10934 child_ctx->parent_ctx = parent_ctx;
10935 child_ctx->parent_gen = parent_ctx->generation;
10937 get_ctx(child_ctx->parent_ctx);
10940 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10942 mutex_unlock(&parent_ctx->mutex);
10944 perf_unpin_context(parent_ctx);
10945 put_ctx(parent_ctx);
10951 * Initialize the perf_event context in task_struct
10953 int perf_event_init_task(struct task_struct *child)
10957 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10958 mutex_init(&child->perf_event_mutex);
10959 INIT_LIST_HEAD(&child->perf_event_list);
10961 for_each_task_context_nr(ctxn) {
10962 ret = perf_event_init_context(child, ctxn);
10964 perf_event_free_task(child);
10972 static void __init perf_event_init_all_cpus(void)
10974 struct swevent_htable *swhash;
10977 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
10979 for_each_possible_cpu(cpu) {
10980 swhash = &per_cpu(swevent_htable, cpu);
10981 mutex_init(&swhash->hlist_mutex);
10982 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10984 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10985 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10987 #ifdef CONFIG_CGROUP_PERF
10988 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10990 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10994 void perf_swevent_init_cpu(unsigned int cpu)
10996 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10998 mutex_lock(&swhash->hlist_mutex);
10999 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11000 struct swevent_hlist *hlist;
11002 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11004 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11006 mutex_unlock(&swhash->hlist_mutex);
11009 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11010 static void __perf_event_exit_context(void *__info)
11012 struct perf_event_context *ctx = __info;
11013 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11014 struct perf_event *event;
11016 raw_spin_lock(&ctx->lock);
11017 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11018 list_for_each_entry(event, &ctx->event_list, event_entry)
11019 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11020 raw_spin_unlock(&ctx->lock);
11023 static void perf_event_exit_cpu_context(int cpu)
11025 struct perf_cpu_context *cpuctx;
11026 struct perf_event_context *ctx;
11029 mutex_lock(&pmus_lock);
11030 list_for_each_entry(pmu, &pmus, entry) {
11031 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11032 ctx = &cpuctx->ctx;
11034 mutex_lock(&ctx->mutex);
11035 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11036 cpuctx->online = 0;
11037 mutex_unlock(&ctx->mutex);
11039 cpumask_clear_cpu(cpu, perf_online_mask);
11040 mutex_unlock(&pmus_lock);
11044 static void perf_event_exit_cpu_context(int cpu) { }
11048 int perf_event_init_cpu(unsigned int cpu)
11050 struct perf_cpu_context *cpuctx;
11051 struct perf_event_context *ctx;
11054 perf_swevent_init_cpu(cpu);
11056 mutex_lock(&pmus_lock);
11057 cpumask_set_cpu(cpu, perf_online_mask);
11058 list_for_each_entry(pmu, &pmus, entry) {
11059 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11060 ctx = &cpuctx->ctx;
11062 mutex_lock(&ctx->mutex);
11063 cpuctx->online = 1;
11064 mutex_unlock(&ctx->mutex);
11066 mutex_unlock(&pmus_lock);
11071 int perf_event_exit_cpu(unsigned int cpu)
11073 perf_event_exit_cpu_context(cpu);
11078 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11082 for_each_online_cpu(cpu)
11083 perf_event_exit_cpu(cpu);
11089 * Run the perf reboot notifier at the very last possible moment so that
11090 * the generic watchdog code runs as long as possible.
11092 static struct notifier_block perf_reboot_notifier = {
11093 .notifier_call = perf_reboot,
11094 .priority = INT_MIN,
11097 void __init perf_event_init(void)
11101 idr_init(&pmu_idr);
11103 perf_event_init_all_cpus();
11104 init_srcu_struct(&pmus_srcu);
11105 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11106 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11107 perf_pmu_register(&perf_task_clock, NULL, -1);
11108 perf_tp_register();
11109 perf_event_init_cpu(smp_processor_id());
11110 register_reboot_notifier(&perf_reboot_notifier);
11112 ret = init_hw_breakpoint();
11113 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11116 * Build time assertion that we keep the data_head at the intended
11117 * location. IOW, validation we got the __reserved[] size right.
11119 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11123 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11126 struct perf_pmu_events_attr *pmu_attr =
11127 container_of(attr, struct perf_pmu_events_attr, attr);
11129 if (pmu_attr->event_str)
11130 return sprintf(page, "%s\n", pmu_attr->event_str);
11134 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11136 static int __init perf_event_sysfs_init(void)
11141 mutex_lock(&pmus_lock);
11143 ret = bus_register(&pmu_bus);
11147 list_for_each_entry(pmu, &pmus, entry) {
11148 if (!pmu->name || pmu->type < 0)
11151 ret = pmu_dev_alloc(pmu);
11152 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11154 pmu_bus_running = 1;
11158 mutex_unlock(&pmus_lock);
11162 device_initcall(perf_event_sysfs_init);
11164 #ifdef CONFIG_CGROUP_PERF
11165 static struct cgroup_subsys_state *
11166 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11168 struct perf_cgroup *jc;
11170 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11172 return ERR_PTR(-ENOMEM);
11174 jc->info = alloc_percpu(struct perf_cgroup_info);
11177 return ERR_PTR(-ENOMEM);
11183 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11185 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11187 free_percpu(jc->info);
11191 static int __perf_cgroup_move(void *info)
11193 struct task_struct *task = info;
11195 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11200 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11202 struct task_struct *task;
11203 struct cgroup_subsys_state *css;
11205 cgroup_taskset_for_each(task, css, tset)
11206 task_function_call(task, __perf_cgroup_move, task);
11209 struct cgroup_subsys perf_event_cgrp_subsys = {
11210 .css_alloc = perf_cgroup_css_alloc,
11211 .css_free = perf_cgroup_css_free,
11212 .attach = perf_cgroup_attach,
11214 * Implicitly enable on dfl hierarchy so that perf events can
11215 * always be filtered by cgroup2 path as long as perf_event
11216 * controller is not mounted on a legacy hierarchy.
11218 .implicit_on_dfl = true,
11221 #endif /* CONFIG_CGROUP_PERF */