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
1237 * cpuctx->mutex / perf_event_context::mutex
1239 static struct perf_event_context *
1240 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1242 struct perf_event_context *ctx;
1246 ctx = READ_ONCE(event->ctx);
1247 if (!atomic_inc_not_zero(&ctx->refcount)) {
1253 mutex_lock_nested(&ctx->mutex, nesting);
1254 if (event->ctx != ctx) {
1255 mutex_unlock(&ctx->mutex);
1263 static inline struct perf_event_context *
1264 perf_event_ctx_lock(struct perf_event *event)
1266 return perf_event_ctx_lock_nested(event, 0);
1269 static void perf_event_ctx_unlock(struct perf_event *event,
1270 struct perf_event_context *ctx)
1272 mutex_unlock(&ctx->mutex);
1277 * This must be done under the ctx->lock, such as to serialize against
1278 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1279 * calling scheduler related locks and ctx->lock nests inside those.
1281 static __must_check struct perf_event_context *
1282 unclone_ctx(struct perf_event_context *ctx)
1284 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1286 lockdep_assert_held(&ctx->lock);
1289 ctx->parent_ctx = NULL;
1295 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1300 * only top level events have the pid namespace they were created in
1303 event = event->parent;
1305 nr = __task_pid_nr_ns(p, type, event->ns);
1306 /* avoid -1 if it is idle thread or runs in another ns */
1307 if (!nr && !pid_alive(p))
1312 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1314 return perf_event_pid_type(event, p, __PIDTYPE_TGID);
1317 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1319 return perf_event_pid_type(event, p, PIDTYPE_PID);
1323 * If we inherit events we want to return the parent event id
1326 static u64 primary_event_id(struct perf_event *event)
1331 id = event->parent->id;
1337 * Get the perf_event_context for a task and lock it.
1339 * This has to cope with with the fact that until it is locked,
1340 * the context could get moved to another task.
1342 static struct perf_event_context *
1343 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1345 struct perf_event_context *ctx;
1349 * One of the few rules of preemptible RCU is that one cannot do
1350 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1351 * part of the read side critical section was irqs-enabled -- see
1352 * rcu_read_unlock_special().
1354 * Since ctx->lock nests under rq->lock we must ensure the entire read
1355 * side critical section has interrupts disabled.
1357 local_irq_save(*flags);
1359 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1362 * If this context is a clone of another, it might
1363 * get swapped for another underneath us by
1364 * perf_event_task_sched_out, though the
1365 * rcu_read_lock() protects us from any context
1366 * getting freed. Lock the context and check if it
1367 * got swapped before we could get the lock, and retry
1368 * if so. If we locked the right context, then it
1369 * can't get swapped on us any more.
1371 raw_spin_lock(&ctx->lock);
1372 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1373 raw_spin_unlock(&ctx->lock);
1375 local_irq_restore(*flags);
1379 if (ctx->task == TASK_TOMBSTONE ||
1380 !atomic_inc_not_zero(&ctx->refcount)) {
1381 raw_spin_unlock(&ctx->lock);
1384 WARN_ON_ONCE(ctx->task != task);
1389 local_irq_restore(*flags);
1394 * Get the context for a task and increment its pin_count so it
1395 * can't get swapped to another task. This also increments its
1396 * reference count so that the context can't get freed.
1398 static struct perf_event_context *
1399 perf_pin_task_context(struct task_struct *task, int ctxn)
1401 struct perf_event_context *ctx;
1402 unsigned long flags;
1404 ctx = perf_lock_task_context(task, ctxn, &flags);
1407 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1412 static void perf_unpin_context(struct perf_event_context *ctx)
1414 unsigned long flags;
1416 raw_spin_lock_irqsave(&ctx->lock, flags);
1418 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1422 * Update the record of the current time in a context.
1424 static void update_context_time(struct perf_event_context *ctx)
1426 u64 now = perf_clock();
1428 ctx->time += now - ctx->timestamp;
1429 ctx->timestamp = now;
1432 static u64 perf_event_time(struct perf_event *event)
1434 struct perf_event_context *ctx = event->ctx;
1436 if (is_cgroup_event(event))
1437 return perf_cgroup_event_time(event);
1439 return ctx ? ctx->time : 0;
1442 static enum event_type_t get_event_type(struct perf_event *event)
1444 struct perf_event_context *ctx = event->ctx;
1445 enum event_type_t event_type;
1447 lockdep_assert_held(&ctx->lock);
1450 * It's 'group type', really, because if our group leader is
1451 * pinned, so are we.
1453 if (event->group_leader != event)
1454 event = event->group_leader;
1456 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1458 event_type |= EVENT_CPU;
1463 static struct list_head *
1464 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1466 if (event->attr.pinned)
1467 return &ctx->pinned_groups;
1469 return &ctx->flexible_groups;
1473 * Add a event from the lists for its context.
1474 * Must be called with ctx->mutex and ctx->lock held.
1477 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1479 lockdep_assert_held(&ctx->lock);
1481 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1482 event->attach_state |= PERF_ATTACH_CONTEXT;
1484 event->tstamp = perf_event_time(event);
1487 * If we're a stand alone event or group leader, we go to the context
1488 * list, group events are kept attached to the group so that
1489 * perf_group_detach can, at all times, locate all siblings.
1491 if (event->group_leader == event) {
1492 struct list_head *list;
1494 event->group_caps = event->event_caps;
1496 list = ctx_group_list(event, ctx);
1497 list_add_tail(&event->group_entry, list);
1500 list_update_cgroup_event(event, ctx, true);
1502 list_add_rcu(&event->event_entry, &ctx->event_list);
1504 if (event->attr.inherit_stat)
1511 * Initialize event state based on the perf_event_attr::disabled.
1513 static inline void perf_event__state_init(struct perf_event *event)
1515 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1516 PERF_EVENT_STATE_INACTIVE;
1519 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1521 int entry = sizeof(u64); /* value */
1525 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1526 size += sizeof(u64);
1528 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1529 size += sizeof(u64);
1531 if (event->attr.read_format & PERF_FORMAT_ID)
1532 entry += sizeof(u64);
1534 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1536 size += sizeof(u64);
1540 event->read_size = size;
1543 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1545 struct perf_sample_data *data;
1548 if (sample_type & PERF_SAMPLE_IP)
1549 size += sizeof(data->ip);
1551 if (sample_type & PERF_SAMPLE_ADDR)
1552 size += sizeof(data->addr);
1554 if (sample_type & PERF_SAMPLE_PERIOD)
1555 size += sizeof(data->period);
1557 if (sample_type & PERF_SAMPLE_WEIGHT)
1558 size += sizeof(data->weight);
1560 if (sample_type & PERF_SAMPLE_READ)
1561 size += event->read_size;
1563 if (sample_type & PERF_SAMPLE_DATA_SRC)
1564 size += sizeof(data->data_src.val);
1566 if (sample_type & PERF_SAMPLE_TRANSACTION)
1567 size += sizeof(data->txn);
1569 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1570 size += sizeof(data->phys_addr);
1572 event->header_size = size;
1576 * Called at perf_event creation and when events are attached/detached from a
1579 static void perf_event__header_size(struct perf_event *event)
1581 __perf_event_read_size(event,
1582 event->group_leader->nr_siblings);
1583 __perf_event_header_size(event, event->attr.sample_type);
1586 static void perf_event__id_header_size(struct perf_event *event)
1588 struct perf_sample_data *data;
1589 u64 sample_type = event->attr.sample_type;
1592 if (sample_type & PERF_SAMPLE_TID)
1593 size += sizeof(data->tid_entry);
1595 if (sample_type & PERF_SAMPLE_TIME)
1596 size += sizeof(data->time);
1598 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1599 size += sizeof(data->id);
1601 if (sample_type & PERF_SAMPLE_ID)
1602 size += sizeof(data->id);
1604 if (sample_type & PERF_SAMPLE_STREAM_ID)
1605 size += sizeof(data->stream_id);
1607 if (sample_type & PERF_SAMPLE_CPU)
1608 size += sizeof(data->cpu_entry);
1610 event->id_header_size = size;
1613 static bool perf_event_validate_size(struct perf_event *event)
1616 * The values computed here will be over-written when we actually
1619 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1620 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1621 perf_event__id_header_size(event);
1624 * Sum the lot; should not exceed the 64k limit we have on records.
1625 * Conservative limit to allow for callchains and other variable fields.
1627 if (event->read_size + event->header_size +
1628 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1634 static void perf_group_attach(struct perf_event *event)
1636 struct perf_event *group_leader = event->group_leader, *pos;
1638 lockdep_assert_held(&event->ctx->lock);
1641 * We can have double attach due to group movement in perf_event_open.
1643 if (event->attach_state & PERF_ATTACH_GROUP)
1646 event->attach_state |= PERF_ATTACH_GROUP;
1648 if (group_leader == event)
1651 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1653 group_leader->group_caps &= event->event_caps;
1655 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1656 group_leader->nr_siblings++;
1658 perf_event__header_size(group_leader);
1660 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1661 perf_event__header_size(pos);
1665 * Remove a event from the lists for its context.
1666 * Must be called with ctx->mutex and ctx->lock held.
1669 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1671 WARN_ON_ONCE(event->ctx != ctx);
1672 lockdep_assert_held(&ctx->lock);
1675 * We can have double detach due to exit/hot-unplug + close.
1677 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1680 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1682 list_update_cgroup_event(event, ctx, false);
1685 if (event->attr.inherit_stat)
1688 list_del_rcu(&event->event_entry);
1690 if (event->group_leader == event)
1691 list_del_init(&event->group_entry);
1694 * If event was in error state, then keep it
1695 * that way, otherwise bogus counts will be
1696 * returned on read(). The only way to get out
1697 * of error state is by explicit re-enabling
1700 if (event->state > PERF_EVENT_STATE_OFF)
1701 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1706 static void perf_group_detach(struct perf_event *event)
1708 struct perf_event *sibling, *tmp;
1709 struct list_head *list = NULL;
1711 lockdep_assert_held(&event->ctx->lock);
1714 * We can have double detach due to exit/hot-unplug + close.
1716 if (!(event->attach_state & PERF_ATTACH_GROUP))
1719 event->attach_state &= ~PERF_ATTACH_GROUP;
1722 * If this is a sibling, remove it from its group.
1724 if (event->group_leader != event) {
1725 list_del_init(&event->group_entry);
1726 event->group_leader->nr_siblings--;
1730 if (!list_empty(&event->group_entry))
1731 list = &event->group_entry;
1734 * If this was a group event with sibling events then
1735 * upgrade the siblings to singleton events by adding them
1736 * to whatever list we are on.
1738 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1740 list_move_tail(&sibling->group_entry, list);
1741 sibling->group_leader = sibling;
1743 /* Inherit group flags from the previous leader */
1744 sibling->group_caps = event->group_caps;
1746 WARN_ON_ONCE(sibling->ctx != event->ctx);
1750 perf_event__header_size(event->group_leader);
1752 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1753 perf_event__header_size(tmp);
1756 static bool is_orphaned_event(struct perf_event *event)
1758 return event->state == PERF_EVENT_STATE_DEAD;
1761 static inline int __pmu_filter_match(struct perf_event *event)
1763 struct pmu *pmu = event->pmu;
1764 return pmu->filter_match ? pmu->filter_match(event) : 1;
1768 * Check whether we should attempt to schedule an event group based on
1769 * PMU-specific filtering. An event group can consist of HW and SW events,
1770 * potentially with a SW leader, so we must check all the filters, to
1771 * determine whether a group is schedulable:
1773 static inline int pmu_filter_match(struct perf_event *event)
1775 struct perf_event *child;
1777 if (!__pmu_filter_match(event))
1780 list_for_each_entry(child, &event->sibling_list, group_entry) {
1781 if (!__pmu_filter_match(child))
1789 event_filter_match(struct perf_event *event)
1791 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1792 perf_cgroup_match(event) && pmu_filter_match(event);
1796 event_sched_out(struct perf_event *event,
1797 struct perf_cpu_context *cpuctx,
1798 struct perf_event_context *ctx)
1800 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1802 WARN_ON_ONCE(event->ctx != ctx);
1803 lockdep_assert_held(&ctx->lock);
1805 if (event->state != PERF_EVENT_STATE_ACTIVE)
1808 perf_pmu_disable(event->pmu);
1810 event->pmu->del(event, 0);
1813 if (event->pending_disable) {
1814 event->pending_disable = 0;
1815 state = PERF_EVENT_STATE_OFF;
1817 perf_event_set_state(event, state);
1819 if (!is_software_event(event))
1820 cpuctx->active_oncpu--;
1821 if (!--ctx->nr_active)
1822 perf_event_ctx_deactivate(ctx);
1823 if (event->attr.freq && event->attr.sample_freq)
1825 if (event->attr.exclusive || !cpuctx->active_oncpu)
1826 cpuctx->exclusive = 0;
1828 perf_pmu_enable(event->pmu);
1832 group_sched_out(struct perf_event *group_event,
1833 struct perf_cpu_context *cpuctx,
1834 struct perf_event_context *ctx)
1836 struct perf_event *event;
1838 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
1841 perf_pmu_disable(ctx->pmu);
1843 event_sched_out(group_event, cpuctx, ctx);
1846 * Schedule out siblings (if any):
1848 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1849 event_sched_out(event, cpuctx, ctx);
1851 perf_pmu_enable(ctx->pmu);
1853 if (group_event->attr.exclusive)
1854 cpuctx->exclusive = 0;
1857 #define DETACH_GROUP 0x01UL
1860 * Cross CPU call to remove a performance event
1862 * We disable the event on the hardware level first. After that we
1863 * remove it from the context list.
1866 __perf_remove_from_context(struct perf_event *event,
1867 struct perf_cpu_context *cpuctx,
1868 struct perf_event_context *ctx,
1871 unsigned long flags = (unsigned long)info;
1873 if (ctx->is_active & EVENT_TIME) {
1874 update_context_time(ctx);
1875 update_cgrp_time_from_cpuctx(cpuctx);
1878 event_sched_out(event, cpuctx, ctx);
1879 if (flags & DETACH_GROUP)
1880 perf_group_detach(event);
1881 list_del_event(event, ctx);
1883 if (!ctx->nr_events && ctx->is_active) {
1886 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1887 cpuctx->task_ctx = NULL;
1893 * Remove the event from a task's (or a CPU's) list of events.
1895 * If event->ctx is a cloned context, callers must make sure that
1896 * every task struct that event->ctx->task could possibly point to
1897 * remains valid. This is OK when called from perf_release since
1898 * that only calls us on the top-level context, which can't be a clone.
1899 * When called from perf_event_exit_task, it's OK because the
1900 * context has been detached from its task.
1902 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1904 struct perf_event_context *ctx = event->ctx;
1906 lockdep_assert_held(&ctx->mutex);
1908 event_function_call(event, __perf_remove_from_context, (void *)flags);
1911 * The above event_function_call() can NO-OP when it hits
1912 * TASK_TOMBSTONE. In that case we must already have been detached
1913 * from the context (by perf_event_exit_event()) but the grouping
1914 * might still be in-tact.
1916 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1917 if ((flags & DETACH_GROUP) &&
1918 (event->attach_state & PERF_ATTACH_GROUP)) {
1920 * Since in that case we cannot possibly be scheduled, simply
1923 raw_spin_lock_irq(&ctx->lock);
1924 perf_group_detach(event);
1925 raw_spin_unlock_irq(&ctx->lock);
1930 * Cross CPU call to disable a performance event
1932 static void __perf_event_disable(struct perf_event *event,
1933 struct perf_cpu_context *cpuctx,
1934 struct perf_event_context *ctx,
1937 if (event->state < PERF_EVENT_STATE_INACTIVE)
1940 if (ctx->is_active & EVENT_TIME) {
1941 update_context_time(ctx);
1942 update_cgrp_time_from_event(event);
1945 if (event == event->group_leader)
1946 group_sched_out(event, cpuctx, ctx);
1948 event_sched_out(event, cpuctx, ctx);
1950 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1956 * If event->ctx is a cloned context, callers must make sure that
1957 * every task struct that event->ctx->task could possibly point to
1958 * remains valid. This condition is satisifed when called through
1959 * perf_event_for_each_child or perf_event_for_each because they
1960 * hold the top-level event's child_mutex, so any descendant that
1961 * goes to exit will block in perf_event_exit_event().
1963 * When called from perf_pending_event it's OK because event->ctx
1964 * is the current context on this CPU and preemption is disabled,
1965 * hence we can't get into perf_event_task_sched_out for this context.
1967 static void _perf_event_disable(struct perf_event *event)
1969 struct perf_event_context *ctx = event->ctx;
1971 raw_spin_lock_irq(&ctx->lock);
1972 if (event->state <= PERF_EVENT_STATE_OFF) {
1973 raw_spin_unlock_irq(&ctx->lock);
1976 raw_spin_unlock_irq(&ctx->lock);
1978 event_function_call(event, __perf_event_disable, NULL);
1981 void perf_event_disable_local(struct perf_event *event)
1983 event_function_local(event, __perf_event_disable, NULL);
1987 * Strictly speaking kernel users cannot create groups and therefore this
1988 * interface does not need the perf_event_ctx_lock() magic.
1990 void perf_event_disable(struct perf_event *event)
1992 struct perf_event_context *ctx;
1994 ctx = perf_event_ctx_lock(event);
1995 _perf_event_disable(event);
1996 perf_event_ctx_unlock(event, ctx);
1998 EXPORT_SYMBOL_GPL(perf_event_disable);
2000 void perf_event_disable_inatomic(struct perf_event *event)
2002 event->pending_disable = 1;
2003 irq_work_queue(&event->pending);
2006 static void perf_set_shadow_time(struct perf_event *event,
2007 struct perf_event_context *ctx)
2010 * use the correct time source for the time snapshot
2012 * We could get by without this by leveraging the
2013 * fact that to get to this function, the caller
2014 * has most likely already called update_context_time()
2015 * and update_cgrp_time_xx() and thus both timestamp
2016 * are identical (or very close). Given that tstamp is,
2017 * already adjusted for cgroup, we could say that:
2018 * tstamp - ctx->timestamp
2020 * tstamp - cgrp->timestamp.
2022 * Then, in perf_output_read(), the calculation would
2023 * work with no changes because:
2024 * - event is guaranteed scheduled in
2025 * - no scheduled out in between
2026 * - thus the timestamp would be the same
2028 * But this is a bit hairy.
2030 * So instead, we have an explicit cgroup call to remain
2031 * within the time time source all along. We believe it
2032 * is cleaner and simpler to understand.
2034 if (is_cgroup_event(event))
2035 perf_cgroup_set_shadow_time(event, event->tstamp);
2037 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2040 #define MAX_INTERRUPTS (~0ULL)
2042 static void perf_log_throttle(struct perf_event *event, int enable);
2043 static void perf_log_itrace_start(struct perf_event *event);
2046 event_sched_in(struct perf_event *event,
2047 struct perf_cpu_context *cpuctx,
2048 struct perf_event_context *ctx)
2052 lockdep_assert_held(&ctx->lock);
2054 if (event->state <= PERF_EVENT_STATE_OFF)
2057 WRITE_ONCE(event->oncpu, smp_processor_id());
2059 * Order event::oncpu write to happen before the ACTIVE state is
2060 * visible. This allows perf_event_{stop,read}() to observe the correct
2061 * ->oncpu if it sees ACTIVE.
2064 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2067 * Unthrottle events, since we scheduled we might have missed several
2068 * ticks already, also for a heavily scheduling task there is little
2069 * guarantee it'll get a tick in a timely manner.
2071 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2072 perf_log_throttle(event, 1);
2073 event->hw.interrupts = 0;
2076 perf_pmu_disable(event->pmu);
2078 perf_set_shadow_time(event, ctx);
2080 perf_log_itrace_start(event);
2082 if (event->pmu->add(event, PERF_EF_START)) {
2083 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2089 if (!is_software_event(event))
2090 cpuctx->active_oncpu++;
2091 if (!ctx->nr_active++)
2092 perf_event_ctx_activate(ctx);
2093 if (event->attr.freq && event->attr.sample_freq)
2096 if (event->attr.exclusive)
2097 cpuctx->exclusive = 1;
2100 perf_pmu_enable(event->pmu);
2106 group_sched_in(struct perf_event *group_event,
2107 struct perf_cpu_context *cpuctx,
2108 struct perf_event_context *ctx)
2110 struct perf_event *event, *partial_group = NULL;
2111 struct pmu *pmu = ctx->pmu;
2113 if (group_event->state == PERF_EVENT_STATE_OFF)
2116 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2118 if (event_sched_in(group_event, cpuctx, ctx)) {
2119 pmu->cancel_txn(pmu);
2120 perf_mux_hrtimer_restart(cpuctx);
2125 * Schedule in siblings as one group (if any):
2127 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2128 if (event_sched_in(event, cpuctx, ctx)) {
2129 partial_group = event;
2134 if (!pmu->commit_txn(pmu))
2139 * Groups can be scheduled in as one unit only, so undo any
2140 * partial group before returning:
2141 * The events up to the failed event are scheduled out normally.
2143 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2144 if (event == partial_group)
2147 event_sched_out(event, cpuctx, ctx);
2149 event_sched_out(group_event, cpuctx, ctx);
2151 pmu->cancel_txn(pmu);
2153 perf_mux_hrtimer_restart(cpuctx);
2159 * Work out whether we can put this event group on the CPU now.
2161 static int group_can_go_on(struct perf_event *event,
2162 struct perf_cpu_context *cpuctx,
2166 * Groups consisting entirely of software events can always go on.
2168 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2171 * If an exclusive group is already on, no other hardware
2174 if (cpuctx->exclusive)
2177 * If this group is exclusive and there are already
2178 * events on the CPU, it can't go on.
2180 if (event->attr.exclusive && cpuctx->active_oncpu)
2183 * Otherwise, try to add it if all previous groups were able
2189 static void add_event_to_ctx(struct perf_event *event,
2190 struct perf_event_context *ctx)
2192 list_add_event(event, ctx);
2193 perf_group_attach(event);
2196 static void ctx_sched_out(struct perf_event_context *ctx,
2197 struct perf_cpu_context *cpuctx,
2198 enum event_type_t event_type);
2200 ctx_sched_in(struct perf_event_context *ctx,
2201 struct perf_cpu_context *cpuctx,
2202 enum event_type_t event_type,
2203 struct task_struct *task);
2205 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2206 struct perf_event_context *ctx,
2207 enum event_type_t event_type)
2209 if (!cpuctx->task_ctx)
2212 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2215 ctx_sched_out(ctx, cpuctx, event_type);
2218 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2219 struct perf_event_context *ctx,
2220 struct task_struct *task)
2222 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2224 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2225 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2227 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2231 * We want to maintain the following priority of scheduling:
2232 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2233 * - task pinned (EVENT_PINNED)
2234 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2235 * - task flexible (EVENT_FLEXIBLE).
2237 * In order to avoid unscheduling and scheduling back in everything every
2238 * time an event is added, only do it for the groups of equal priority and
2241 * This can be called after a batch operation on task events, in which case
2242 * event_type is a bit mask of the types of events involved. For CPU events,
2243 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2245 static void ctx_resched(struct perf_cpu_context *cpuctx,
2246 struct perf_event_context *task_ctx,
2247 enum event_type_t event_type)
2249 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2250 bool cpu_event = !!(event_type & EVENT_CPU);
2253 * If pinned groups are involved, flexible groups also need to be
2256 if (event_type & EVENT_PINNED)
2257 event_type |= EVENT_FLEXIBLE;
2259 perf_pmu_disable(cpuctx->ctx.pmu);
2261 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2264 * Decide which cpu ctx groups to schedule out based on the types
2265 * of events that caused rescheduling:
2266 * - EVENT_CPU: schedule out corresponding groups;
2267 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2268 * - otherwise, do nothing more.
2271 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2272 else if (ctx_event_type & EVENT_PINNED)
2273 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2275 perf_event_sched_in(cpuctx, task_ctx, current);
2276 perf_pmu_enable(cpuctx->ctx.pmu);
2280 * Cross CPU call to install and enable a performance event
2282 * Very similar to remote_function() + event_function() but cannot assume that
2283 * things like ctx->is_active and cpuctx->task_ctx are set.
2285 static int __perf_install_in_context(void *info)
2287 struct perf_event *event = info;
2288 struct perf_event_context *ctx = event->ctx;
2289 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2290 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2291 bool reprogram = true;
2294 raw_spin_lock(&cpuctx->ctx.lock);
2296 raw_spin_lock(&ctx->lock);
2299 reprogram = (ctx->task == current);
2302 * If the task is running, it must be running on this CPU,
2303 * otherwise we cannot reprogram things.
2305 * If its not running, we don't care, ctx->lock will
2306 * serialize against it becoming runnable.
2308 if (task_curr(ctx->task) && !reprogram) {
2313 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2314 } else if (task_ctx) {
2315 raw_spin_lock(&task_ctx->lock);
2319 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2320 add_event_to_ctx(event, ctx);
2321 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2323 add_event_to_ctx(event, ctx);
2327 perf_ctx_unlock(cpuctx, task_ctx);
2333 * Attach a performance event to a context.
2335 * Very similar to event_function_call, see comment there.
2338 perf_install_in_context(struct perf_event_context *ctx,
2339 struct perf_event *event,
2342 struct task_struct *task = READ_ONCE(ctx->task);
2344 lockdep_assert_held(&ctx->mutex);
2346 if (event->cpu != -1)
2350 * Ensures that if we can observe event->ctx, both the event and ctx
2351 * will be 'complete'. See perf_iterate_sb_cpu().
2353 smp_store_release(&event->ctx, ctx);
2356 cpu_function_call(cpu, __perf_install_in_context, event);
2361 * Should not happen, we validate the ctx is still alive before calling.
2363 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2367 * Installing events is tricky because we cannot rely on ctx->is_active
2368 * to be set in case this is the nr_events 0 -> 1 transition.
2370 * Instead we use task_curr(), which tells us if the task is running.
2371 * However, since we use task_curr() outside of rq::lock, we can race
2372 * against the actual state. This means the result can be wrong.
2374 * If we get a false positive, we retry, this is harmless.
2376 * If we get a false negative, things are complicated. If we are after
2377 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2378 * value must be correct. If we're before, it doesn't matter since
2379 * perf_event_context_sched_in() will program the counter.
2381 * However, this hinges on the remote context switch having observed
2382 * our task->perf_event_ctxp[] store, such that it will in fact take
2383 * ctx::lock in perf_event_context_sched_in().
2385 * We do this by task_function_call(), if the IPI fails to hit the task
2386 * we know any future context switch of task must see the
2387 * perf_event_ctpx[] store.
2391 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2392 * task_cpu() load, such that if the IPI then does not find the task
2393 * running, a future context switch of that task must observe the
2398 if (!task_function_call(task, __perf_install_in_context, event))
2401 raw_spin_lock_irq(&ctx->lock);
2403 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2405 * Cannot happen because we already checked above (which also
2406 * cannot happen), and we hold ctx->mutex, which serializes us
2407 * against perf_event_exit_task_context().
2409 raw_spin_unlock_irq(&ctx->lock);
2413 * If the task is not running, ctx->lock will avoid it becoming so,
2414 * thus we can safely install the event.
2416 if (task_curr(task)) {
2417 raw_spin_unlock_irq(&ctx->lock);
2420 add_event_to_ctx(event, ctx);
2421 raw_spin_unlock_irq(&ctx->lock);
2425 * Cross CPU call to enable a performance event
2427 static void __perf_event_enable(struct perf_event *event,
2428 struct perf_cpu_context *cpuctx,
2429 struct perf_event_context *ctx,
2432 struct perf_event *leader = event->group_leader;
2433 struct perf_event_context *task_ctx;
2435 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2436 event->state <= PERF_EVENT_STATE_ERROR)
2440 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2442 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2444 if (!ctx->is_active)
2447 if (!event_filter_match(event)) {
2448 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2453 * If the event is in a group and isn't the group leader,
2454 * then don't put it on unless the group is on.
2456 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2457 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2461 task_ctx = cpuctx->task_ctx;
2463 WARN_ON_ONCE(task_ctx != ctx);
2465 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2471 * If event->ctx is a cloned context, callers must make sure that
2472 * every task struct that event->ctx->task could possibly point to
2473 * remains valid. This condition is satisfied when called through
2474 * perf_event_for_each_child or perf_event_for_each as described
2475 * for perf_event_disable.
2477 static void _perf_event_enable(struct perf_event *event)
2479 struct perf_event_context *ctx = event->ctx;
2481 raw_spin_lock_irq(&ctx->lock);
2482 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2483 event->state < PERF_EVENT_STATE_ERROR) {
2484 raw_spin_unlock_irq(&ctx->lock);
2489 * If the event is in error state, clear that first.
2491 * That way, if we see the event in error state below, we know that it
2492 * has gone back into error state, as distinct from the task having
2493 * been scheduled away before the cross-call arrived.
2495 if (event->state == PERF_EVENT_STATE_ERROR)
2496 event->state = PERF_EVENT_STATE_OFF;
2497 raw_spin_unlock_irq(&ctx->lock);
2499 event_function_call(event, __perf_event_enable, NULL);
2503 * See perf_event_disable();
2505 void perf_event_enable(struct perf_event *event)
2507 struct perf_event_context *ctx;
2509 ctx = perf_event_ctx_lock(event);
2510 _perf_event_enable(event);
2511 perf_event_ctx_unlock(event, ctx);
2513 EXPORT_SYMBOL_GPL(perf_event_enable);
2515 struct stop_event_data {
2516 struct perf_event *event;
2517 unsigned int restart;
2520 static int __perf_event_stop(void *info)
2522 struct stop_event_data *sd = info;
2523 struct perf_event *event = sd->event;
2525 /* if it's already INACTIVE, do nothing */
2526 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2529 /* matches smp_wmb() in event_sched_in() */
2533 * There is a window with interrupts enabled before we get here,
2534 * so we need to check again lest we try to stop another CPU's event.
2536 if (READ_ONCE(event->oncpu) != smp_processor_id())
2539 event->pmu->stop(event, PERF_EF_UPDATE);
2542 * May race with the actual stop (through perf_pmu_output_stop()),
2543 * but it is only used for events with AUX ring buffer, and such
2544 * events will refuse to restart because of rb::aux_mmap_count==0,
2545 * see comments in perf_aux_output_begin().
2547 * Since this is happening on a event-local CPU, no trace is lost
2551 event->pmu->start(event, 0);
2556 static int perf_event_stop(struct perf_event *event, int restart)
2558 struct stop_event_data sd = {
2565 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2568 /* matches smp_wmb() in event_sched_in() */
2572 * We only want to restart ACTIVE events, so if the event goes
2573 * inactive here (event->oncpu==-1), there's nothing more to do;
2574 * fall through with ret==-ENXIO.
2576 ret = cpu_function_call(READ_ONCE(event->oncpu),
2577 __perf_event_stop, &sd);
2578 } while (ret == -EAGAIN);
2584 * In order to contain the amount of racy and tricky in the address filter
2585 * configuration management, it is a two part process:
2587 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2588 * we update the addresses of corresponding vmas in
2589 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2590 * (p2) when an event is scheduled in (pmu::add), it calls
2591 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2592 * if the generation has changed since the previous call.
2594 * If (p1) happens while the event is active, we restart it to force (p2).
2596 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2597 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2599 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2600 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2602 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2605 void perf_event_addr_filters_sync(struct perf_event *event)
2607 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2609 if (!has_addr_filter(event))
2612 raw_spin_lock(&ifh->lock);
2613 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2614 event->pmu->addr_filters_sync(event);
2615 event->hw.addr_filters_gen = event->addr_filters_gen;
2617 raw_spin_unlock(&ifh->lock);
2619 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2621 static int _perf_event_refresh(struct perf_event *event, int refresh)
2624 * not supported on inherited events
2626 if (event->attr.inherit || !is_sampling_event(event))
2629 atomic_add(refresh, &event->event_limit);
2630 _perf_event_enable(event);
2636 * See perf_event_disable()
2638 int perf_event_refresh(struct perf_event *event, int refresh)
2640 struct perf_event_context *ctx;
2643 ctx = perf_event_ctx_lock(event);
2644 ret = _perf_event_refresh(event, refresh);
2645 perf_event_ctx_unlock(event, ctx);
2649 EXPORT_SYMBOL_GPL(perf_event_refresh);
2651 static void ctx_sched_out(struct perf_event_context *ctx,
2652 struct perf_cpu_context *cpuctx,
2653 enum event_type_t event_type)
2655 int is_active = ctx->is_active;
2656 struct perf_event *event;
2658 lockdep_assert_held(&ctx->lock);
2660 if (likely(!ctx->nr_events)) {
2662 * See __perf_remove_from_context().
2664 WARN_ON_ONCE(ctx->is_active);
2666 WARN_ON_ONCE(cpuctx->task_ctx);
2670 ctx->is_active &= ~event_type;
2671 if (!(ctx->is_active & EVENT_ALL))
2675 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2676 if (!ctx->is_active)
2677 cpuctx->task_ctx = NULL;
2681 * Always update time if it was set; not only when it changes.
2682 * Otherwise we can 'forget' to update time for any but the last
2683 * context we sched out. For example:
2685 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2686 * ctx_sched_out(.event_type = EVENT_PINNED)
2688 * would only update time for the pinned events.
2690 if (is_active & EVENT_TIME) {
2691 /* update (and stop) ctx time */
2692 update_context_time(ctx);
2693 update_cgrp_time_from_cpuctx(cpuctx);
2696 is_active ^= ctx->is_active; /* changed bits */
2698 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2701 perf_pmu_disable(ctx->pmu);
2702 if (is_active & EVENT_PINNED) {
2703 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2704 group_sched_out(event, cpuctx, ctx);
2707 if (is_active & EVENT_FLEXIBLE) {
2708 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2709 group_sched_out(event, cpuctx, ctx);
2711 perf_pmu_enable(ctx->pmu);
2715 * Test whether two contexts are equivalent, i.e. whether they have both been
2716 * cloned from the same version of the same context.
2718 * Equivalence is measured using a generation number in the context that is
2719 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2720 * and list_del_event().
2722 static int context_equiv(struct perf_event_context *ctx1,
2723 struct perf_event_context *ctx2)
2725 lockdep_assert_held(&ctx1->lock);
2726 lockdep_assert_held(&ctx2->lock);
2728 /* Pinning disables the swap optimization */
2729 if (ctx1->pin_count || ctx2->pin_count)
2732 /* If ctx1 is the parent of ctx2 */
2733 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2736 /* If ctx2 is the parent of ctx1 */
2737 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2741 * If ctx1 and ctx2 have the same parent; we flatten the parent
2742 * hierarchy, see perf_event_init_context().
2744 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2745 ctx1->parent_gen == ctx2->parent_gen)
2752 static void __perf_event_sync_stat(struct perf_event *event,
2753 struct perf_event *next_event)
2757 if (!event->attr.inherit_stat)
2761 * Update the event value, we cannot use perf_event_read()
2762 * because we're in the middle of a context switch and have IRQs
2763 * disabled, which upsets smp_call_function_single(), however
2764 * we know the event must be on the current CPU, therefore we
2765 * don't need to use it.
2767 if (event->state == PERF_EVENT_STATE_ACTIVE)
2768 event->pmu->read(event);
2770 perf_event_update_time(event);
2773 * In order to keep per-task stats reliable we need to flip the event
2774 * values when we flip the contexts.
2776 value = local64_read(&next_event->count);
2777 value = local64_xchg(&event->count, value);
2778 local64_set(&next_event->count, value);
2780 swap(event->total_time_enabled, next_event->total_time_enabled);
2781 swap(event->total_time_running, next_event->total_time_running);
2784 * Since we swizzled the values, update the user visible data too.
2786 perf_event_update_userpage(event);
2787 perf_event_update_userpage(next_event);
2790 static void perf_event_sync_stat(struct perf_event_context *ctx,
2791 struct perf_event_context *next_ctx)
2793 struct perf_event *event, *next_event;
2798 update_context_time(ctx);
2800 event = list_first_entry(&ctx->event_list,
2801 struct perf_event, event_entry);
2803 next_event = list_first_entry(&next_ctx->event_list,
2804 struct perf_event, event_entry);
2806 while (&event->event_entry != &ctx->event_list &&
2807 &next_event->event_entry != &next_ctx->event_list) {
2809 __perf_event_sync_stat(event, next_event);
2811 event = list_next_entry(event, event_entry);
2812 next_event = list_next_entry(next_event, event_entry);
2816 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2817 struct task_struct *next)
2819 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2820 struct perf_event_context *next_ctx;
2821 struct perf_event_context *parent, *next_parent;
2822 struct perf_cpu_context *cpuctx;
2828 cpuctx = __get_cpu_context(ctx);
2829 if (!cpuctx->task_ctx)
2833 next_ctx = next->perf_event_ctxp[ctxn];
2837 parent = rcu_dereference(ctx->parent_ctx);
2838 next_parent = rcu_dereference(next_ctx->parent_ctx);
2840 /* If neither context have a parent context; they cannot be clones. */
2841 if (!parent && !next_parent)
2844 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2846 * Looks like the two contexts are clones, so we might be
2847 * able to optimize the context switch. We lock both
2848 * contexts and check that they are clones under the
2849 * lock (including re-checking that neither has been
2850 * uncloned in the meantime). It doesn't matter which
2851 * order we take the locks because no other cpu could
2852 * be trying to lock both of these tasks.
2854 raw_spin_lock(&ctx->lock);
2855 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2856 if (context_equiv(ctx, next_ctx)) {
2857 WRITE_ONCE(ctx->task, next);
2858 WRITE_ONCE(next_ctx->task, task);
2860 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2863 * RCU_INIT_POINTER here is safe because we've not
2864 * modified the ctx and the above modification of
2865 * ctx->task and ctx->task_ctx_data are immaterial
2866 * since those values are always verified under
2867 * ctx->lock which we're now holding.
2869 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2870 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2874 perf_event_sync_stat(ctx, next_ctx);
2876 raw_spin_unlock(&next_ctx->lock);
2877 raw_spin_unlock(&ctx->lock);
2883 raw_spin_lock(&ctx->lock);
2884 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2885 raw_spin_unlock(&ctx->lock);
2889 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2891 void perf_sched_cb_dec(struct pmu *pmu)
2893 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2895 this_cpu_dec(perf_sched_cb_usages);
2897 if (!--cpuctx->sched_cb_usage)
2898 list_del(&cpuctx->sched_cb_entry);
2902 void perf_sched_cb_inc(struct pmu *pmu)
2904 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2906 if (!cpuctx->sched_cb_usage++)
2907 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2909 this_cpu_inc(perf_sched_cb_usages);
2913 * This function provides the context switch callback to the lower code
2914 * layer. It is invoked ONLY when the context switch callback is enabled.
2916 * This callback is relevant even to per-cpu events; for example multi event
2917 * PEBS requires this to provide PID/TID information. This requires we flush
2918 * all queued PEBS records before we context switch to a new task.
2920 static void perf_pmu_sched_task(struct task_struct *prev,
2921 struct task_struct *next,
2924 struct perf_cpu_context *cpuctx;
2930 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2931 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
2933 if (WARN_ON_ONCE(!pmu->sched_task))
2936 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2937 perf_pmu_disable(pmu);
2939 pmu->sched_task(cpuctx->task_ctx, sched_in);
2941 perf_pmu_enable(pmu);
2942 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2946 static void perf_event_switch(struct task_struct *task,
2947 struct task_struct *next_prev, bool sched_in);
2949 #define for_each_task_context_nr(ctxn) \
2950 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2953 * Called from scheduler to remove the events of the current task,
2954 * with interrupts disabled.
2956 * We stop each event and update the event value in event->count.
2958 * This does not protect us against NMI, but disable()
2959 * sets the disabled bit in the control field of event _before_
2960 * accessing the event control register. If a NMI hits, then it will
2961 * not restart the event.
2963 void __perf_event_task_sched_out(struct task_struct *task,
2964 struct task_struct *next)
2968 if (__this_cpu_read(perf_sched_cb_usages))
2969 perf_pmu_sched_task(task, next, false);
2971 if (atomic_read(&nr_switch_events))
2972 perf_event_switch(task, next, false);
2974 for_each_task_context_nr(ctxn)
2975 perf_event_context_sched_out(task, ctxn, next);
2978 * if cgroup events exist on this CPU, then we need
2979 * to check if we have to switch out PMU state.
2980 * cgroup event are system-wide mode only
2982 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2983 perf_cgroup_sched_out(task, next);
2987 * Called with IRQs disabled
2989 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2990 enum event_type_t event_type)
2992 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2996 ctx_pinned_sched_in(struct perf_event_context *ctx,
2997 struct perf_cpu_context *cpuctx)
2999 struct perf_event *event;
3001 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3002 if (event->state <= PERF_EVENT_STATE_OFF)
3004 if (!event_filter_match(event))
3007 if (group_can_go_on(event, cpuctx, 1))
3008 group_sched_in(event, cpuctx, ctx);
3011 * If this pinned group hasn't been scheduled,
3012 * put it in error state.
3014 if (event->state == PERF_EVENT_STATE_INACTIVE)
3015 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3020 ctx_flexible_sched_in(struct perf_event_context *ctx,
3021 struct perf_cpu_context *cpuctx)
3023 struct perf_event *event;
3026 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3027 /* Ignore events in OFF or ERROR state */
3028 if (event->state <= PERF_EVENT_STATE_OFF)
3031 * Listen to the 'cpu' scheduling filter constraint
3034 if (!event_filter_match(event))
3037 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3038 if (group_sched_in(event, cpuctx, ctx))
3045 ctx_sched_in(struct perf_event_context *ctx,
3046 struct perf_cpu_context *cpuctx,
3047 enum event_type_t event_type,
3048 struct task_struct *task)
3050 int is_active = ctx->is_active;
3053 lockdep_assert_held(&ctx->lock);
3055 if (likely(!ctx->nr_events))
3058 ctx->is_active |= (event_type | EVENT_TIME);
3061 cpuctx->task_ctx = ctx;
3063 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3066 is_active ^= ctx->is_active; /* changed bits */
3068 if (is_active & EVENT_TIME) {
3069 /* start ctx time */
3071 ctx->timestamp = now;
3072 perf_cgroup_set_timestamp(task, ctx);
3076 * First go through the list and put on any pinned groups
3077 * in order to give them the best chance of going on.
3079 if (is_active & EVENT_PINNED)
3080 ctx_pinned_sched_in(ctx, cpuctx);
3082 /* Then walk through the lower prio flexible groups */
3083 if (is_active & EVENT_FLEXIBLE)
3084 ctx_flexible_sched_in(ctx, cpuctx);
3087 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3088 enum event_type_t event_type,
3089 struct task_struct *task)
3091 struct perf_event_context *ctx = &cpuctx->ctx;
3093 ctx_sched_in(ctx, cpuctx, event_type, task);
3096 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3097 struct task_struct *task)
3099 struct perf_cpu_context *cpuctx;
3101 cpuctx = __get_cpu_context(ctx);
3102 if (cpuctx->task_ctx == ctx)
3105 perf_ctx_lock(cpuctx, ctx);
3107 * We must check ctx->nr_events while holding ctx->lock, such
3108 * that we serialize against perf_install_in_context().
3110 if (!ctx->nr_events)
3113 perf_pmu_disable(ctx->pmu);
3115 * We want to keep the following priority order:
3116 * cpu pinned (that don't need to move), task pinned,
3117 * cpu flexible, task flexible.
3119 * However, if task's ctx is not carrying any pinned
3120 * events, no need to flip the cpuctx's events around.
3122 if (!list_empty(&ctx->pinned_groups))
3123 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3124 perf_event_sched_in(cpuctx, ctx, task);
3125 perf_pmu_enable(ctx->pmu);
3128 perf_ctx_unlock(cpuctx, ctx);
3132 * Called from scheduler to add the events of the current task
3133 * with interrupts disabled.
3135 * We restore the event value and then enable it.
3137 * This does not protect us against NMI, but enable()
3138 * sets the enabled bit in the control field of event _before_
3139 * accessing the event control register. If a NMI hits, then it will
3140 * keep the event running.
3142 void __perf_event_task_sched_in(struct task_struct *prev,
3143 struct task_struct *task)
3145 struct perf_event_context *ctx;
3149 * If cgroup events exist on this CPU, then we need to check if we have
3150 * to switch in PMU state; cgroup event are system-wide mode only.
3152 * Since cgroup events are CPU events, we must schedule these in before
3153 * we schedule in the task events.
3155 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3156 perf_cgroup_sched_in(prev, task);
3158 for_each_task_context_nr(ctxn) {
3159 ctx = task->perf_event_ctxp[ctxn];
3163 perf_event_context_sched_in(ctx, task);
3166 if (atomic_read(&nr_switch_events))
3167 perf_event_switch(task, prev, true);
3169 if (__this_cpu_read(perf_sched_cb_usages))
3170 perf_pmu_sched_task(prev, task, true);
3173 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3175 u64 frequency = event->attr.sample_freq;
3176 u64 sec = NSEC_PER_SEC;
3177 u64 divisor, dividend;
3179 int count_fls, nsec_fls, frequency_fls, sec_fls;
3181 count_fls = fls64(count);
3182 nsec_fls = fls64(nsec);
3183 frequency_fls = fls64(frequency);
3187 * We got @count in @nsec, with a target of sample_freq HZ
3188 * the target period becomes:
3191 * period = -------------------
3192 * @nsec * sample_freq
3197 * Reduce accuracy by one bit such that @a and @b converge
3198 * to a similar magnitude.
3200 #define REDUCE_FLS(a, b) \
3202 if (a##_fls > b##_fls) { \
3212 * Reduce accuracy until either term fits in a u64, then proceed with
3213 * the other, so that finally we can do a u64/u64 division.
3215 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3216 REDUCE_FLS(nsec, frequency);
3217 REDUCE_FLS(sec, count);
3220 if (count_fls + sec_fls > 64) {
3221 divisor = nsec * frequency;
3223 while (count_fls + sec_fls > 64) {
3224 REDUCE_FLS(count, sec);
3228 dividend = count * sec;
3230 dividend = count * sec;
3232 while (nsec_fls + frequency_fls > 64) {
3233 REDUCE_FLS(nsec, frequency);
3237 divisor = nsec * frequency;
3243 return div64_u64(dividend, divisor);
3246 static DEFINE_PER_CPU(int, perf_throttled_count);
3247 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3249 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3251 struct hw_perf_event *hwc = &event->hw;
3252 s64 period, sample_period;
3255 period = perf_calculate_period(event, nsec, count);
3257 delta = (s64)(period - hwc->sample_period);
3258 delta = (delta + 7) / 8; /* low pass filter */
3260 sample_period = hwc->sample_period + delta;
3265 hwc->sample_period = sample_period;
3267 if (local64_read(&hwc->period_left) > 8*sample_period) {
3269 event->pmu->stop(event, PERF_EF_UPDATE);
3271 local64_set(&hwc->period_left, 0);
3274 event->pmu->start(event, PERF_EF_RELOAD);
3279 * combine freq adjustment with unthrottling to avoid two passes over the
3280 * events. At the same time, make sure, having freq events does not change
3281 * the rate of unthrottling as that would introduce bias.
3283 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3286 struct perf_event *event;
3287 struct hw_perf_event *hwc;
3288 u64 now, period = TICK_NSEC;
3292 * only need to iterate over all events iff:
3293 * - context have events in frequency mode (needs freq adjust)
3294 * - there are events to unthrottle on this cpu
3296 if (!(ctx->nr_freq || needs_unthr))
3299 raw_spin_lock(&ctx->lock);
3300 perf_pmu_disable(ctx->pmu);
3302 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3303 if (event->state != PERF_EVENT_STATE_ACTIVE)
3306 if (!event_filter_match(event))
3309 perf_pmu_disable(event->pmu);
3313 if (hwc->interrupts == MAX_INTERRUPTS) {
3314 hwc->interrupts = 0;
3315 perf_log_throttle(event, 1);
3316 event->pmu->start(event, 0);
3319 if (!event->attr.freq || !event->attr.sample_freq)
3323 * stop the event and update event->count
3325 event->pmu->stop(event, PERF_EF_UPDATE);
3327 now = local64_read(&event->count);
3328 delta = now - hwc->freq_count_stamp;
3329 hwc->freq_count_stamp = now;
3333 * reload only if value has changed
3334 * we have stopped the event so tell that
3335 * to perf_adjust_period() to avoid stopping it
3339 perf_adjust_period(event, period, delta, false);
3341 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3343 perf_pmu_enable(event->pmu);
3346 perf_pmu_enable(ctx->pmu);
3347 raw_spin_unlock(&ctx->lock);
3351 * Round-robin a context's events:
3353 static void rotate_ctx(struct perf_event_context *ctx)
3356 * Rotate the first entry last of non-pinned groups. Rotation might be
3357 * disabled by the inheritance code.
3359 if (!ctx->rotate_disable)
3360 list_rotate_left(&ctx->flexible_groups);
3363 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3365 struct perf_event_context *ctx = NULL;
3368 if (cpuctx->ctx.nr_events) {
3369 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3373 ctx = cpuctx->task_ctx;
3374 if (ctx && ctx->nr_events) {
3375 if (ctx->nr_events != ctx->nr_active)
3382 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3383 perf_pmu_disable(cpuctx->ctx.pmu);
3385 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3387 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3389 rotate_ctx(&cpuctx->ctx);
3393 perf_event_sched_in(cpuctx, ctx, current);
3395 perf_pmu_enable(cpuctx->ctx.pmu);
3396 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3402 void perf_event_task_tick(void)
3404 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3405 struct perf_event_context *ctx, *tmp;
3408 lockdep_assert_irqs_disabled();
3410 __this_cpu_inc(perf_throttled_seq);
3411 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3412 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3414 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3415 perf_adjust_freq_unthr_context(ctx, throttled);
3418 static int event_enable_on_exec(struct perf_event *event,
3419 struct perf_event_context *ctx)
3421 if (!event->attr.enable_on_exec)
3424 event->attr.enable_on_exec = 0;
3425 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3428 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3434 * Enable all of a task's events that have been marked enable-on-exec.
3435 * This expects task == current.
3437 static void perf_event_enable_on_exec(int ctxn)
3439 struct perf_event_context *ctx, *clone_ctx = NULL;
3440 enum event_type_t event_type = 0;
3441 struct perf_cpu_context *cpuctx;
3442 struct perf_event *event;
3443 unsigned long flags;
3446 local_irq_save(flags);
3447 ctx = current->perf_event_ctxp[ctxn];
3448 if (!ctx || !ctx->nr_events)
3451 cpuctx = __get_cpu_context(ctx);
3452 perf_ctx_lock(cpuctx, ctx);
3453 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3454 list_for_each_entry(event, &ctx->event_list, event_entry) {
3455 enabled |= event_enable_on_exec(event, ctx);
3456 event_type |= get_event_type(event);
3460 * Unclone and reschedule this context if we enabled any event.
3463 clone_ctx = unclone_ctx(ctx);
3464 ctx_resched(cpuctx, ctx, event_type);
3466 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3468 perf_ctx_unlock(cpuctx, ctx);
3471 local_irq_restore(flags);
3477 struct perf_read_data {
3478 struct perf_event *event;
3483 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3485 u16 local_pkg, event_pkg;
3487 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3488 int local_cpu = smp_processor_id();
3490 event_pkg = topology_physical_package_id(event_cpu);
3491 local_pkg = topology_physical_package_id(local_cpu);
3493 if (event_pkg == local_pkg)
3501 * Cross CPU call to read the hardware event
3503 static void __perf_event_read(void *info)
3505 struct perf_read_data *data = info;
3506 struct perf_event *sub, *event = data->event;
3507 struct perf_event_context *ctx = event->ctx;
3508 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3509 struct pmu *pmu = event->pmu;
3512 * If this is a task context, we need to check whether it is
3513 * the current task context of this cpu. If not it has been
3514 * scheduled out before the smp call arrived. In that case
3515 * event->count would have been updated to a recent sample
3516 * when the event was scheduled out.
3518 if (ctx->task && cpuctx->task_ctx != ctx)
3521 raw_spin_lock(&ctx->lock);
3522 if (ctx->is_active & EVENT_TIME) {
3523 update_context_time(ctx);
3524 update_cgrp_time_from_event(event);
3527 perf_event_update_time(event);
3529 perf_event_update_sibling_time(event);
3531 if (event->state != PERF_EVENT_STATE_ACTIVE)
3540 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3544 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3545 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3547 * Use sibling's PMU rather than @event's since
3548 * sibling could be on different (eg: software) PMU.
3550 sub->pmu->read(sub);
3554 data->ret = pmu->commit_txn(pmu);
3557 raw_spin_unlock(&ctx->lock);
3560 static inline u64 perf_event_count(struct perf_event *event)
3562 return local64_read(&event->count) + atomic64_read(&event->child_count);
3566 * NMI-safe method to read a local event, that is an event that
3568 * - either for the current task, or for this CPU
3569 * - does not have inherit set, for inherited task events
3570 * will not be local and we cannot read them atomically
3571 * - must not have a pmu::count method
3573 int perf_event_read_local(struct perf_event *event, u64 *value,
3574 u64 *enabled, u64 *running)
3576 unsigned long flags;
3580 * Disabling interrupts avoids all counter scheduling (context
3581 * switches, timer based rotation and IPIs).
3583 local_irq_save(flags);
3586 * It must not be an event with inherit set, we cannot read
3587 * all child counters from atomic context.
3589 if (event->attr.inherit) {
3594 /* If this is a per-task event, it must be for current */
3595 if ((event->attach_state & PERF_ATTACH_TASK) &&
3596 event->hw.target != current) {
3601 /* If this is a per-CPU event, it must be for this CPU */
3602 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3603 event->cpu != smp_processor_id()) {
3609 * If the event is currently on this CPU, its either a per-task event,
3610 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3613 if (event->oncpu == smp_processor_id())
3614 event->pmu->read(event);
3616 *value = local64_read(&event->count);
3617 if (enabled || running) {
3618 u64 now = event->shadow_ctx_time + perf_clock();
3619 u64 __enabled, __running;
3621 __perf_update_times(event, now, &__enabled, &__running);
3623 *enabled = __enabled;
3625 *running = __running;
3628 local_irq_restore(flags);
3633 static int perf_event_read(struct perf_event *event, bool group)
3635 enum perf_event_state state = READ_ONCE(event->state);
3636 int event_cpu, ret = 0;
3639 * If event is enabled and currently active on a CPU, update the
3640 * value in the event structure:
3643 if (state == PERF_EVENT_STATE_ACTIVE) {
3644 struct perf_read_data data;
3647 * Orders the ->state and ->oncpu loads such that if we see
3648 * ACTIVE we must also see the right ->oncpu.
3650 * Matches the smp_wmb() from event_sched_in().
3654 event_cpu = READ_ONCE(event->oncpu);
3655 if ((unsigned)event_cpu >= nr_cpu_ids)
3658 data = (struct perf_read_data){
3665 event_cpu = __perf_event_read_cpu(event, event_cpu);
3668 * Purposely ignore the smp_call_function_single() return
3671 * If event_cpu isn't a valid CPU it means the event got
3672 * scheduled out and that will have updated the event count.
3674 * Therefore, either way, we'll have an up-to-date event count
3677 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3681 } else if (state == PERF_EVENT_STATE_INACTIVE) {
3682 struct perf_event_context *ctx = event->ctx;
3683 unsigned long flags;
3685 raw_spin_lock_irqsave(&ctx->lock, flags);
3686 state = event->state;
3687 if (state != PERF_EVENT_STATE_INACTIVE) {
3688 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3693 * May read while context is not active (e.g., thread is
3694 * blocked), in that case we cannot update context time
3696 if (ctx->is_active & EVENT_TIME) {
3697 update_context_time(ctx);
3698 update_cgrp_time_from_event(event);
3701 perf_event_update_time(event);
3703 perf_event_update_sibling_time(event);
3704 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3711 * Initialize the perf_event context in a task_struct:
3713 static void __perf_event_init_context(struct perf_event_context *ctx)
3715 raw_spin_lock_init(&ctx->lock);
3716 mutex_init(&ctx->mutex);
3717 INIT_LIST_HEAD(&ctx->active_ctx_list);
3718 INIT_LIST_HEAD(&ctx->pinned_groups);
3719 INIT_LIST_HEAD(&ctx->flexible_groups);
3720 INIT_LIST_HEAD(&ctx->event_list);
3721 atomic_set(&ctx->refcount, 1);
3724 static struct perf_event_context *
3725 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3727 struct perf_event_context *ctx;
3729 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3733 __perf_event_init_context(ctx);
3736 get_task_struct(task);
3743 static struct task_struct *
3744 find_lively_task_by_vpid(pid_t vpid)
3746 struct task_struct *task;
3752 task = find_task_by_vpid(vpid);
3754 get_task_struct(task);
3758 return ERR_PTR(-ESRCH);
3764 * Returns a matching context with refcount and pincount.
3766 static struct perf_event_context *
3767 find_get_context(struct pmu *pmu, struct task_struct *task,
3768 struct perf_event *event)
3770 struct perf_event_context *ctx, *clone_ctx = NULL;
3771 struct perf_cpu_context *cpuctx;
3772 void *task_ctx_data = NULL;
3773 unsigned long flags;
3775 int cpu = event->cpu;
3778 /* Must be root to operate on a CPU event: */
3779 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3780 return ERR_PTR(-EACCES);
3782 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3791 ctxn = pmu->task_ctx_nr;
3795 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3796 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3797 if (!task_ctx_data) {
3804 ctx = perf_lock_task_context(task, ctxn, &flags);
3806 clone_ctx = unclone_ctx(ctx);
3809 if (task_ctx_data && !ctx->task_ctx_data) {
3810 ctx->task_ctx_data = task_ctx_data;
3811 task_ctx_data = NULL;
3813 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3818 ctx = alloc_perf_context(pmu, task);
3823 if (task_ctx_data) {
3824 ctx->task_ctx_data = task_ctx_data;
3825 task_ctx_data = NULL;
3829 mutex_lock(&task->perf_event_mutex);
3831 * If it has already passed perf_event_exit_task().
3832 * we must see PF_EXITING, it takes this mutex too.
3834 if (task->flags & PF_EXITING)
3836 else if (task->perf_event_ctxp[ctxn])
3841 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3843 mutex_unlock(&task->perf_event_mutex);
3845 if (unlikely(err)) {
3854 kfree(task_ctx_data);
3858 kfree(task_ctx_data);
3859 return ERR_PTR(err);
3862 static void perf_event_free_filter(struct perf_event *event);
3863 static void perf_event_free_bpf_prog(struct perf_event *event);
3865 static void free_event_rcu(struct rcu_head *head)
3867 struct perf_event *event;
3869 event = container_of(head, struct perf_event, rcu_head);
3871 put_pid_ns(event->ns);
3872 perf_event_free_filter(event);
3876 static void ring_buffer_attach(struct perf_event *event,
3877 struct ring_buffer *rb);
3879 static void detach_sb_event(struct perf_event *event)
3881 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3883 raw_spin_lock(&pel->lock);
3884 list_del_rcu(&event->sb_list);
3885 raw_spin_unlock(&pel->lock);
3888 static bool is_sb_event(struct perf_event *event)
3890 struct perf_event_attr *attr = &event->attr;
3895 if (event->attach_state & PERF_ATTACH_TASK)
3898 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3899 attr->comm || attr->comm_exec ||
3901 attr->context_switch)
3906 static void unaccount_pmu_sb_event(struct perf_event *event)
3908 if (is_sb_event(event))
3909 detach_sb_event(event);
3912 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3917 if (is_cgroup_event(event))
3918 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3921 #ifdef CONFIG_NO_HZ_FULL
3922 static DEFINE_SPINLOCK(nr_freq_lock);
3925 static void unaccount_freq_event_nohz(void)
3927 #ifdef CONFIG_NO_HZ_FULL
3928 spin_lock(&nr_freq_lock);
3929 if (atomic_dec_and_test(&nr_freq_events))
3930 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3931 spin_unlock(&nr_freq_lock);
3935 static void unaccount_freq_event(void)
3937 if (tick_nohz_full_enabled())
3938 unaccount_freq_event_nohz();
3940 atomic_dec(&nr_freq_events);
3943 static void unaccount_event(struct perf_event *event)
3950 if (event->attach_state & PERF_ATTACH_TASK)
3952 if (event->attr.mmap || event->attr.mmap_data)
3953 atomic_dec(&nr_mmap_events);
3954 if (event->attr.comm)
3955 atomic_dec(&nr_comm_events);
3956 if (event->attr.namespaces)
3957 atomic_dec(&nr_namespaces_events);
3958 if (event->attr.task)
3959 atomic_dec(&nr_task_events);
3960 if (event->attr.freq)
3961 unaccount_freq_event();
3962 if (event->attr.context_switch) {
3964 atomic_dec(&nr_switch_events);
3966 if (is_cgroup_event(event))
3968 if (has_branch_stack(event))
3972 if (!atomic_add_unless(&perf_sched_count, -1, 1))
3973 schedule_delayed_work(&perf_sched_work, HZ);
3976 unaccount_event_cpu(event, event->cpu);
3978 unaccount_pmu_sb_event(event);
3981 static void perf_sched_delayed(struct work_struct *work)
3983 mutex_lock(&perf_sched_mutex);
3984 if (atomic_dec_and_test(&perf_sched_count))
3985 static_branch_disable(&perf_sched_events);
3986 mutex_unlock(&perf_sched_mutex);
3990 * The following implement mutual exclusion of events on "exclusive" pmus
3991 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3992 * at a time, so we disallow creating events that might conflict, namely:
3994 * 1) cpu-wide events in the presence of per-task events,
3995 * 2) per-task events in the presence of cpu-wide events,
3996 * 3) two matching events on the same context.
3998 * The former two cases are handled in the allocation path (perf_event_alloc(),
3999 * _free_event()), the latter -- before the first perf_install_in_context().
4001 static int exclusive_event_init(struct perf_event *event)
4003 struct pmu *pmu = event->pmu;
4005 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4009 * Prevent co-existence of per-task and cpu-wide events on the
4010 * same exclusive pmu.
4012 * Negative pmu::exclusive_cnt means there are cpu-wide
4013 * events on this "exclusive" pmu, positive means there are
4016 * Since this is called in perf_event_alloc() path, event::ctx
4017 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4018 * to mean "per-task event", because unlike other attach states it
4019 * never gets cleared.
4021 if (event->attach_state & PERF_ATTACH_TASK) {
4022 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4025 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4032 static void exclusive_event_destroy(struct perf_event *event)
4034 struct pmu *pmu = event->pmu;
4036 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4039 /* see comment in exclusive_event_init() */
4040 if (event->attach_state & PERF_ATTACH_TASK)
4041 atomic_dec(&pmu->exclusive_cnt);
4043 atomic_inc(&pmu->exclusive_cnt);
4046 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4048 if ((e1->pmu == e2->pmu) &&
4049 (e1->cpu == e2->cpu ||
4056 /* Called under the same ctx::mutex as perf_install_in_context() */
4057 static bool exclusive_event_installable(struct perf_event *event,
4058 struct perf_event_context *ctx)
4060 struct perf_event *iter_event;
4061 struct pmu *pmu = event->pmu;
4063 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4066 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4067 if (exclusive_event_match(iter_event, event))
4074 static void perf_addr_filters_splice(struct perf_event *event,
4075 struct list_head *head);
4077 static void _free_event(struct perf_event *event)
4079 irq_work_sync(&event->pending);
4081 unaccount_event(event);
4085 * Can happen when we close an event with re-directed output.
4087 * Since we have a 0 refcount, perf_mmap_close() will skip
4088 * over us; possibly making our ring_buffer_put() the last.
4090 mutex_lock(&event->mmap_mutex);
4091 ring_buffer_attach(event, NULL);
4092 mutex_unlock(&event->mmap_mutex);
4095 if (is_cgroup_event(event))
4096 perf_detach_cgroup(event);
4098 if (!event->parent) {
4099 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4100 put_callchain_buffers();
4103 perf_event_free_bpf_prog(event);
4104 perf_addr_filters_splice(event, NULL);
4105 kfree(event->addr_filters_offs);
4108 event->destroy(event);
4111 put_ctx(event->ctx);
4113 exclusive_event_destroy(event);
4114 module_put(event->pmu->module);
4116 call_rcu(&event->rcu_head, free_event_rcu);
4120 * Used to free events which have a known refcount of 1, such as in error paths
4121 * where the event isn't exposed yet and inherited events.
4123 static void free_event(struct perf_event *event)
4125 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4126 "unexpected event refcount: %ld; ptr=%p\n",
4127 atomic_long_read(&event->refcount), event)) {
4128 /* leak to avoid use-after-free */
4136 * Remove user event from the owner task.
4138 static void perf_remove_from_owner(struct perf_event *event)
4140 struct task_struct *owner;
4144 * Matches the smp_store_release() in perf_event_exit_task(). If we
4145 * observe !owner it means the list deletion is complete and we can
4146 * indeed free this event, otherwise we need to serialize on
4147 * owner->perf_event_mutex.
4149 owner = READ_ONCE(event->owner);
4152 * Since delayed_put_task_struct() also drops the last
4153 * task reference we can safely take a new reference
4154 * while holding the rcu_read_lock().
4156 get_task_struct(owner);
4162 * If we're here through perf_event_exit_task() we're already
4163 * holding ctx->mutex which would be an inversion wrt. the
4164 * normal lock order.
4166 * However we can safely take this lock because its the child
4169 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4172 * We have to re-check the event->owner field, if it is cleared
4173 * we raced with perf_event_exit_task(), acquiring the mutex
4174 * ensured they're done, and we can proceed with freeing the
4178 list_del_init(&event->owner_entry);
4179 smp_store_release(&event->owner, NULL);
4181 mutex_unlock(&owner->perf_event_mutex);
4182 put_task_struct(owner);
4186 static void put_event(struct perf_event *event)
4188 if (!atomic_long_dec_and_test(&event->refcount))
4195 * Kill an event dead; while event:refcount will preserve the event
4196 * object, it will not preserve its functionality. Once the last 'user'
4197 * gives up the object, we'll destroy the thing.
4199 int perf_event_release_kernel(struct perf_event *event)
4201 struct perf_event_context *ctx = event->ctx;
4202 struct perf_event *child, *tmp;
4203 LIST_HEAD(free_list);
4206 * If we got here through err_file: fput(event_file); we will not have
4207 * attached to a context yet.
4210 WARN_ON_ONCE(event->attach_state &
4211 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4215 if (!is_kernel_event(event))
4216 perf_remove_from_owner(event);
4218 ctx = perf_event_ctx_lock(event);
4219 WARN_ON_ONCE(ctx->parent_ctx);
4220 perf_remove_from_context(event, DETACH_GROUP);
4222 raw_spin_lock_irq(&ctx->lock);
4224 * Mark this event as STATE_DEAD, there is no external reference to it
4227 * Anybody acquiring event->child_mutex after the below loop _must_
4228 * also see this, most importantly inherit_event() which will avoid
4229 * placing more children on the list.
4231 * Thus this guarantees that we will in fact observe and kill _ALL_
4234 event->state = PERF_EVENT_STATE_DEAD;
4235 raw_spin_unlock_irq(&ctx->lock);
4237 perf_event_ctx_unlock(event, ctx);
4240 mutex_lock(&event->child_mutex);
4241 list_for_each_entry(child, &event->child_list, child_list) {
4244 * Cannot change, child events are not migrated, see the
4245 * comment with perf_event_ctx_lock_nested().
4247 ctx = READ_ONCE(child->ctx);
4249 * Since child_mutex nests inside ctx::mutex, we must jump
4250 * through hoops. We start by grabbing a reference on the ctx.
4252 * Since the event cannot get freed while we hold the
4253 * child_mutex, the context must also exist and have a !0
4259 * Now that we have a ctx ref, we can drop child_mutex, and
4260 * acquire ctx::mutex without fear of it going away. Then we
4261 * can re-acquire child_mutex.
4263 mutex_unlock(&event->child_mutex);
4264 mutex_lock(&ctx->mutex);
4265 mutex_lock(&event->child_mutex);
4268 * Now that we hold ctx::mutex and child_mutex, revalidate our
4269 * state, if child is still the first entry, it didn't get freed
4270 * and we can continue doing so.
4272 tmp = list_first_entry_or_null(&event->child_list,
4273 struct perf_event, child_list);
4275 perf_remove_from_context(child, DETACH_GROUP);
4276 list_move(&child->child_list, &free_list);
4278 * This matches the refcount bump in inherit_event();
4279 * this can't be the last reference.
4284 mutex_unlock(&event->child_mutex);
4285 mutex_unlock(&ctx->mutex);
4289 mutex_unlock(&event->child_mutex);
4291 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4292 list_del(&child->child_list);
4297 put_event(event); /* Must be the 'last' reference */
4300 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4303 * Called when the last reference to the file is gone.
4305 static int perf_release(struct inode *inode, struct file *file)
4307 perf_event_release_kernel(file->private_data);
4311 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4313 struct perf_event *child;
4319 mutex_lock(&event->child_mutex);
4321 (void)perf_event_read(event, false);
4322 total += perf_event_count(event);
4324 *enabled += event->total_time_enabled +
4325 atomic64_read(&event->child_total_time_enabled);
4326 *running += event->total_time_running +
4327 atomic64_read(&event->child_total_time_running);
4329 list_for_each_entry(child, &event->child_list, child_list) {
4330 (void)perf_event_read(child, false);
4331 total += perf_event_count(child);
4332 *enabled += child->total_time_enabled;
4333 *running += child->total_time_running;
4335 mutex_unlock(&event->child_mutex);
4340 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4342 struct perf_event_context *ctx;
4345 ctx = perf_event_ctx_lock(event);
4346 count = __perf_event_read_value(event, enabled, running);
4347 perf_event_ctx_unlock(event, ctx);
4351 EXPORT_SYMBOL_GPL(perf_event_read_value);
4353 static int __perf_read_group_add(struct perf_event *leader,
4354 u64 read_format, u64 *values)
4356 struct perf_event_context *ctx = leader->ctx;
4357 struct perf_event *sub;
4358 unsigned long flags;
4359 int n = 1; /* skip @nr */
4362 ret = perf_event_read(leader, true);
4366 raw_spin_lock_irqsave(&ctx->lock, flags);
4369 * Since we co-schedule groups, {enabled,running} times of siblings
4370 * will be identical to those of the leader, so we only publish one
4373 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4374 values[n++] += leader->total_time_enabled +
4375 atomic64_read(&leader->child_total_time_enabled);
4378 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4379 values[n++] += leader->total_time_running +
4380 atomic64_read(&leader->child_total_time_running);
4384 * Write {count,id} tuples for every sibling.
4386 values[n++] += perf_event_count(leader);
4387 if (read_format & PERF_FORMAT_ID)
4388 values[n++] = primary_event_id(leader);
4390 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4391 values[n++] += perf_event_count(sub);
4392 if (read_format & PERF_FORMAT_ID)
4393 values[n++] = primary_event_id(sub);
4396 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4400 static int perf_read_group(struct perf_event *event,
4401 u64 read_format, char __user *buf)
4403 struct perf_event *leader = event->group_leader, *child;
4404 struct perf_event_context *ctx = leader->ctx;
4408 lockdep_assert_held(&ctx->mutex);
4410 values = kzalloc(event->read_size, GFP_KERNEL);
4414 values[0] = 1 + leader->nr_siblings;
4417 * By locking the child_mutex of the leader we effectively
4418 * lock the child list of all siblings.. XXX explain how.
4420 mutex_lock(&leader->child_mutex);
4422 ret = __perf_read_group_add(leader, read_format, values);
4426 list_for_each_entry(child, &leader->child_list, child_list) {
4427 ret = __perf_read_group_add(child, read_format, values);
4432 mutex_unlock(&leader->child_mutex);
4434 ret = event->read_size;
4435 if (copy_to_user(buf, values, event->read_size))
4440 mutex_unlock(&leader->child_mutex);
4446 static int perf_read_one(struct perf_event *event,
4447 u64 read_format, char __user *buf)
4449 u64 enabled, running;
4453 values[n++] = __perf_event_read_value(event, &enabled, &running);
4454 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4455 values[n++] = enabled;
4456 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4457 values[n++] = running;
4458 if (read_format & PERF_FORMAT_ID)
4459 values[n++] = primary_event_id(event);
4461 if (copy_to_user(buf, values, n * sizeof(u64)))
4464 return n * sizeof(u64);
4467 static bool is_event_hup(struct perf_event *event)
4471 if (event->state > PERF_EVENT_STATE_EXIT)
4474 mutex_lock(&event->child_mutex);
4475 no_children = list_empty(&event->child_list);
4476 mutex_unlock(&event->child_mutex);
4481 * Read the performance event - simple non blocking version for now
4484 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4486 u64 read_format = event->attr.read_format;
4490 * Return end-of-file for a read on a event that is in
4491 * error state (i.e. because it was pinned but it couldn't be
4492 * scheduled on to the CPU at some point).
4494 if (event->state == PERF_EVENT_STATE_ERROR)
4497 if (count < event->read_size)
4500 WARN_ON_ONCE(event->ctx->parent_ctx);
4501 if (read_format & PERF_FORMAT_GROUP)
4502 ret = perf_read_group(event, read_format, buf);
4504 ret = perf_read_one(event, read_format, buf);
4510 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4512 struct perf_event *event = file->private_data;
4513 struct perf_event_context *ctx;
4516 ctx = perf_event_ctx_lock(event);
4517 ret = __perf_read(event, buf, count);
4518 perf_event_ctx_unlock(event, ctx);
4523 static unsigned int perf_poll(struct file *file, poll_table *wait)
4525 struct perf_event *event = file->private_data;
4526 struct ring_buffer *rb;
4527 unsigned int events = POLLHUP;
4529 poll_wait(file, &event->waitq, wait);
4531 if (is_event_hup(event))
4535 * Pin the event->rb by taking event->mmap_mutex; otherwise
4536 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4538 mutex_lock(&event->mmap_mutex);
4541 events = atomic_xchg(&rb->poll, 0);
4542 mutex_unlock(&event->mmap_mutex);
4546 static void _perf_event_reset(struct perf_event *event)
4548 (void)perf_event_read(event, false);
4549 local64_set(&event->count, 0);
4550 perf_event_update_userpage(event);
4554 * Holding the top-level event's child_mutex means that any
4555 * descendant process that has inherited this event will block
4556 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4557 * task existence requirements of perf_event_enable/disable.
4559 static void perf_event_for_each_child(struct perf_event *event,
4560 void (*func)(struct perf_event *))
4562 struct perf_event *child;
4564 WARN_ON_ONCE(event->ctx->parent_ctx);
4566 mutex_lock(&event->child_mutex);
4568 list_for_each_entry(child, &event->child_list, child_list)
4570 mutex_unlock(&event->child_mutex);
4573 static void perf_event_for_each(struct perf_event *event,
4574 void (*func)(struct perf_event *))
4576 struct perf_event_context *ctx = event->ctx;
4577 struct perf_event *sibling;
4579 lockdep_assert_held(&ctx->mutex);
4581 event = event->group_leader;
4583 perf_event_for_each_child(event, func);
4584 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4585 perf_event_for_each_child(sibling, func);
4588 static void __perf_event_period(struct perf_event *event,
4589 struct perf_cpu_context *cpuctx,
4590 struct perf_event_context *ctx,
4593 u64 value = *((u64 *)info);
4596 if (event->attr.freq) {
4597 event->attr.sample_freq = value;
4599 event->attr.sample_period = value;
4600 event->hw.sample_period = value;
4603 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4605 perf_pmu_disable(ctx->pmu);
4607 * We could be throttled; unthrottle now to avoid the tick
4608 * trying to unthrottle while we already re-started the event.
4610 if (event->hw.interrupts == MAX_INTERRUPTS) {
4611 event->hw.interrupts = 0;
4612 perf_log_throttle(event, 1);
4614 event->pmu->stop(event, PERF_EF_UPDATE);
4617 local64_set(&event->hw.period_left, 0);
4620 event->pmu->start(event, PERF_EF_RELOAD);
4621 perf_pmu_enable(ctx->pmu);
4625 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4629 if (!is_sampling_event(event))
4632 if (copy_from_user(&value, arg, sizeof(value)))
4638 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4641 event_function_call(event, __perf_event_period, &value);
4646 static const struct file_operations perf_fops;
4648 static inline int perf_fget_light(int fd, struct fd *p)
4650 struct fd f = fdget(fd);
4654 if (f.file->f_op != &perf_fops) {
4662 static int perf_event_set_output(struct perf_event *event,
4663 struct perf_event *output_event);
4664 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4665 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4667 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4669 void (*func)(struct perf_event *);
4673 case PERF_EVENT_IOC_ENABLE:
4674 func = _perf_event_enable;
4676 case PERF_EVENT_IOC_DISABLE:
4677 func = _perf_event_disable;
4679 case PERF_EVENT_IOC_RESET:
4680 func = _perf_event_reset;
4683 case PERF_EVENT_IOC_REFRESH:
4684 return _perf_event_refresh(event, arg);
4686 case PERF_EVENT_IOC_PERIOD:
4687 return perf_event_period(event, (u64 __user *)arg);
4689 case PERF_EVENT_IOC_ID:
4691 u64 id = primary_event_id(event);
4693 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4698 case PERF_EVENT_IOC_SET_OUTPUT:
4702 struct perf_event *output_event;
4704 ret = perf_fget_light(arg, &output);
4707 output_event = output.file->private_data;
4708 ret = perf_event_set_output(event, output_event);
4711 ret = perf_event_set_output(event, NULL);
4716 case PERF_EVENT_IOC_SET_FILTER:
4717 return perf_event_set_filter(event, (void __user *)arg);
4719 case PERF_EVENT_IOC_SET_BPF:
4720 return perf_event_set_bpf_prog(event, arg);
4722 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4723 struct ring_buffer *rb;
4726 rb = rcu_dereference(event->rb);
4727 if (!rb || !rb->nr_pages) {
4731 rb_toggle_paused(rb, !!arg);
4739 if (flags & PERF_IOC_FLAG_GROUP)
4740 perf_event_for_each(event, func);
4742 perf_event_for_each_child(event, func);
4747 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4749 struct perf_event *event = file->private_data;
4750 struct perf_event_context *ctx;
4753 ctx = perf_event_ctx_lock(event);
4754 ret = _perf_ioctl(event, cmd, arg);
4755 perf_event_ctx_unlock(event, ctx);
4760 #ifdef CONFIG_COMPAT
4761 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4764 switch (_IOC_NR(cmd)) {
4765 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4766 case _IOC_NR(PERF_EVENT_IOC_ID):
4767 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4768 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4769 cmd &= ~IOCSIZE_MASK;
4770 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4774 return perf_ioctl(file, cmd, arg);
4777 # define perf_compat_ioctl NULL
4780 int perf_event_task_enable(void)
4782 struct perf_event_context *ctx;
4783 struct perf_event *event;
4785 mutex_lock(¤t->perf_event_mutex);
4786 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4787 ctx = perf_event_ctx_lock(event);
4788 perf_event_for_each_child(event, _perf_event_enable);
4789 perf_event_ctx_unlock(event, ctx);
4791 mutex_unlock(¤t->perf_event_mutex);
4796 int perf_event_task_disable(void)
4798 struct perf_event_context *ctx;
4799 struct perf_event *event;
4801 mutex_lock(¤t->perf_event_mutex);
4802 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4803 ctx = perf_event_ctx_lock(event);
4804 perf_event_for_each_child(event, _perf_event_disable);
4805 perf_event_ctx_unlock(event, ctx);
4807 mutex_unlock(¤t->perf_event_mutex);
4812 static int perf_event_index(struct perf_event *event)
4814 if (event->hw.state & PERF_HES_STOPPED)
4817 if (event->state != PERF_EVENT_STATE_ACTIVE)
4820 return event->pmu->event_idx(event);
4823 static void calc_timer_values(struct perf_event *event,
4830 *now = perf_clock();
4831 ctx_time = event->shadow_ctx_time + *now;
4832 __perf_update_times(event, ctx_time, enabled, running);
4835 static void perf_event_init_userpage(struct perf_event *event)
4837 struct perf_event_mmap_page *userpg;
4838 struct ring_buffer *rb;
4841 rb = rcu_dereference(event->rb);
4845 userpg = rb->user_page;
4847 /* Allow new userspace to detect that bit 0 is deprecated */
4848 userpg->cap_bit0_is_deprecated = 1;
4849 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4850 userpg->data_offset = PAGE_SIZE;
4851 userpg->data_size = perf_data_size(rb);
4857 void __weak arch_perf_update_userpage(
4858 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4863 * Callers need to ensure there can be no nesting of this function, otherwise
4864 * the seqlock logic goes bad. We can not serialize this because the arch
4865 * code calls this from NMI context.
4867 void perf_event_update_userpage(struct perf_event *event)
4869 struct perf_event_mmap_page *userpg;
4870 struct ring_buffer *rb;
4871 u64 enabled, running, now;
4874 rb = rcu_dereference(event->rb);
4879 * compute total_time_enabled, total_time_running
4880 * based on snapshot values taken when the event
4881 * was last scheduled in.
4883 * we cannot simply called update_context_time()
4884 * because of locking issue as we can be called in
4887 calc_timer_values(event, &now, &enabled, &running);
4889 userpg = rb->user_page;
4891 * Disable preemption so as to not let the corresponding user-space
4892 * spin too long if we get preempted.
4897 userpg->index = perf_event_index(event);
4898 userpg->offset = perf_event_count(event);
4900 userpg->offset -= local64_read(&event->hw.prev_count);
4902 userpg->time_enabled = enabled +
4903 atomic64_read(&event->child_total_time_enabled);
4905 userpg->time_running = running +
4906 atomic64_read(&event->child_total_time_running);
4908 arch_perf_update_userpage(event, userpg, now);
4916 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
4918 static int perf_mmap_fault(struct vm_fault *vmf)
4920 struct perf_event *event = vmf->vma->vm_file->private_data;
4921 struct ring_buffer *rb;
4922 int ret = VM_FAULT_SIGBUS;
4924 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4925 if (vmf->pgoff == 0)
4931 rb = rcu_dereference(event->rb);
4935 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4938 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4942 get_page(vmf->page);
4943 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4944 vmf->page->index = vmf->pgoff;
4953 static void ring_buffer_attach(struct perf_event *event,
4954 struct ring_buffer *rb)
4956 struct ring_buffer *old_rb = NULL;
4957 unsigned long flags;
4961 * Should be impossible, we set this when removing
4962 * event->rb_entry and wait/clear when adding event->rb_entry.
4964 WARN_ON_ONCE(event->rcu_pending);
4967 spin_lock_irqsave(&old_rb->event_lock, flags);
4968 list_del_rcu(&event->rb_entry);
4969 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4971 event->rcu_batches = get_state_synchronize_rcu();
4972 event->rcu_pending = 1;
4976 if (event->rcu_pending) {
4977 cond_synchronize_rcu(event->rcu_batches);
4978 event->rcu_pending = 0;
4981 spin_lock_irqsave(&rb->event_lock, flags);
4982 list_add_rcu(&event->rb_entry, &rb->event_list);
4983 spin_unlock_irqrestore(&rb->event_lock, flags);
4987 * Avoid racing with perf_mmap_close(AUX): stop the event
4988 * before swizzling the event::rb pointer; if it's getting
4989 * unmapped, its aux_mmap_count will be 0 and it won't
4990 * restart. See the comment in __perf_pmu_output_stop().
4992 * Data will inevitably be lost when set_output is done in
4993 * mid-air, but then again, whoever does it like this is
4994 * not in for the data anyway.
4997 perf_event_stop(event, 0);
4999 rcu_assign_pointer(event->rb, rb);
5002 ring_buffer_put(old_rb);
5004 * Since we detached before setting the new rb, so that we
5005 * could attach the new rb, we could have missed a wakeup.
5008 wake_up_all(&event->waitq);
5012 static void ring_buffer_wakeup(struct perf_event *event)
5014 struct ring_buffer *rb;
5017 rb = rcu_dereference(event->rb);
5019 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5020 wake_up_all(&event->waitq);
5025 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5027 struct ring_buffer *rb;
5030 rb = rcu_dereference(event->rb);
5032 if (!atomic_inc_not_zero(&rb->refcount))
5040 void ring_buffer_put(struct ring_buffer *rb)
5042 if (!atomic_dec_and_test(&rb->refcount))
5045 WARN_ON_ONCE(!list_empty(&rb->event_list));
5047 call_rcu(&rb->rcu_head, rb_free_rcu);
5050 static void perf_mmap_open(struct vm_area_struct *vma)
5052 struct perf_event *event = vma->vm_file->private_data;
5054 atomic_inc(&event->mmap_count);
5055 atomic_inc(&event->rb->mmap_count);
5058 atomic_inc(&event->rb->aux_mmap_count);
5060 if (event->pmu->event_mapped)
5061 event->pmu->event_mapped(event, vma->vm_mm);
5064 static void perf_pmu_output_stop(struct perf_event *event);
5067 * A buffer can be mmap()ed multiple times; either directly through the same
5068 * event, or through other events by use of perf_event_set_output().
5070 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5071 * the buffer here, where we still have a VM context. This means we need
5072 * to detach all events redirecting to us.
5074 static void perf_mmap_close(struct vm_area_struct *vma)
5076 struct perf_event *event = vma->vm_file->private_data;
5078 struct ring_buffer *rb = ring_buffer_get(event);
5079 struct user_struct *mmap_user = rb->mmap_user;
5080 int mmap_locked = rb->mmap_locked;
5081 unsigned long size = perf_data_size(rb);
5083 if (event->pmu->event_unmapped)
5084 event->pmu->event_unmapped(event, vma->vm_mm);
5087 * rb->aux_mmap_count will always drop before rb->mmap_count and
5088 * event->mmap_count, so it is ok to use event->mmap_mutex to
5089 * serialize with perf_mmap here.
5091 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5092 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5094 * Stop all AUX events that are writing to this buffer,
5095 * so that we can free its AUX pages and corresponding PMU
5096 * data. Note that after rb::aux_mmap_count dropped to zero,
5097 * they won't start any more (see perf_aux_output_begin()).
5099 perf_pmu_output_stop(event);
5101 /* now it's safe to free the pages */
5102 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5103 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5105 /* this has to be the last one */
5107 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5109 mutex_unlock(&event->mmap_mutex);
5112 atomic_dec(&rb->mmap_count);
5114 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5117 ring_buffer_attach(event, NULL);
5118 mutex_unlock(&event->mmap_mutex);
5120 /* If there's still other mmap()s of this buffer, we're done. */
5121 if (atomic_read(&rb->mmap_count))
5125 * No other mmap()s, detach from all other events that might redirect
5126 * into the now unreachable buffer. Somewhat complicated by the
5127 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5131 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5132 if (!atomic_long_inc_not_zero(&event->refcount)) {
5134 * This event is en-route to free_event() which will
5135 * detach it and remove it from the list.
5141 mutex_lock(&event->mmap_mutex);
5143 * Check we didn't race with perf_event_set_output() which can
5144 * swizzle the rb from under us while we were waiting to
5145 * acquire mmap_mutex.
5147 * If we find a different rb; ignore this event, a next
5148 * iteration will no longer find it on the list. We have to
5149 * still restart the iteration to make sure we're not now
5150 * iterating the wrong list.
5152 if (event->rb == rb)
5153 ring_buffer_attach(event, NULL);
5155 mutex_unlock(&event->mmap_mutex);
5159 * Restart the iteration; either we're on the wrong list or
5160 * destroyed its integrity by doing a deletion.
5167 * It could be there's still a few 0-ref events on the list; they'll
5168 * get cleaned up by free_event() -- they'll also still have their
5169 * ref on the rb and will free it whenever they are done with it.
5171 * Aside from that, this buffer is 'fully' detached and unmapped,
5172 * undo the VM accounting.
5175 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5176 vma->vm_mm->pinned_vm -= mmap_locked;
5177 free_uid(mmap_user);
5180 ring_buffer_put(rb); /* could be last */
5183 static const struct vm_operations_struct perf_mmap_vmops = {
5184 .open = perf_mmap_open,
5185 .close = perf_mmap_close, /* non mergable */
5186 .fault = perf_mmap_fault,
5187 .page_mkwrite = perf_mmap_fault,
5190 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5192 struct perf_event *event = file->private_data;
5193 unsigned long user_locked, user_lock_limit;
5194 struct user_struct *user = current_user();
5195 unsigned long locked, lock_limit;
5196 struct ring_buffer *rb = NULL;
5197 unsigned long vma_size;
5198 unsigned long nr_pages;
5199 long user_extra = 0, extra = 0;
5200 int ret = 0, flags = 0;
5203 * Don't allow mmap() of inherited per-task counters. This would
5204 * create a performance issue due to all children writing to the
5207 if (event->cpu == -1 && event->attr.inherit)
5210 if (!(vma->vm_flags & VM_SHARED))
5213 vma_size = vma->vm_end - vma->vm_start;
5215 if (vma->vm_pgoff == 0) {
5216 nr_pages = (vma_size / PAGE_SIZE) - 1;
5219 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5220 * mapped, all subsequent mappings should have the same size
5221 * and offset. Must be above the normal perf buffer.
5223 u64 aux_offset, aux_size;
5228 nr_pages = vma_size / PAGE_SIZE;
5230 mutex_lock(&event->mmap_mutex);
5237 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5238 aux_size = READ_ONCE(rb->user_page->aux_size);
5240 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5243 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5246 /* already mapped with a different offset */
5247 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5250 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5253 /* already mapped with a different size */
5254 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5257 if (!is_power_of_2(nr_pages))
5260 if (!atomic_inc_not_zero(&rb->mmap_count))
5263 if (rb_has_aux(rb)) {
5264 atomic_inc(&rb->aux_mmap_count);
5269 atomic_set(&rb->aux_mmap_count, 1);
5270 user_extra = nr_pages;
5276 * If we have rb pages ensure they're a power-of-two number, so we
5277 * can do bitmasks instead of modulo.
5279 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5282 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5285 WARN_ON_ONCE(event->ctx->parent_ctx);
5287 mutex_lock(&event->mmap_mutex);
5289 if (event->rb->nr_pages != nr_pages) {
5294 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5296 * Raced against perf_mmap_close() through
5297 * perf_event_set_output(). Try again, hope for better
5300 mutex_unlock(&event->mmap_mutex);
5307 user_extra = nr_pages + 1;
5310 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5313 * Increase the limit linearly with more CPUs:
5315 user_lock_limit *= num_online_cpus();
5317 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5319 if (user_locked > user_lock_limit)
5320 extra = user_locked - user_lock_limit;
5322 lock_limit = rlimit(RLIMIT_MEMLOCK);
5323 lock_limit >>= PAGE_SHIFT;
5324 locked = vma->vm_mm->pinned_vm + extra;
5326 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5327 !capable(CAP_IPC_LOCK)) {
5332 WARN_ON(!rb && event->rb);
5334 if (vma->vm_flags & VM_WRITE)
5335 flags |= RING_BUFFER_WRITABLE;
5338 rb = rb_alloc(nr_pages,
5339 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5347 atomic_set(&rb->mmap_count, 1);
5348 rb->mmap_user = get_current_user();
5349 rb->mmap_locked = extra;
5351 ring_buffer_attach(event, rb);
5353 perf_event_init_userpage(event);
5354 perf_event_update_userpage(event);
5356 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5357 event->attr.aux_watermark, flags);
5359 rb->aux_mmap_locked = extra;
5364 atomic_long_add(user_extra, &user->locked_vm);
5365 vma->vm_mm->pinned_vm += extra;
5367 atomic_inc(&event->mmap_count);
5369 atomic_dec(&rb->mmap_count);
5372 mutex_unlock(&event->mmap_mutex);
5375 * Since pinned accounting is per vm we cannot allow fork() to copy our
5378 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5379 vma->vm_ops = &perf_mmap_vmops;
5381 if (event->pmu->event_mapped)
5382 event->pmu->event_mapped(event, vma->vm_mm);
5387 static int perf_fasync(int fd, struct file *filp, int on)
5389 struct inode *inode = file_inode(filp);
5390 struct perf_event *event = filp->private_data;
5394 retval = fasync_helper(fd, filp, on, &event->fasync);
5395 inode_unlock(inode);
5403 static const struct file_operations perf_fops = {
5404 .llseek = no_llseek,
5405 .release = perf_release,
5408 .unlocked_ioctl = perf_ioctl,
5409 .compat_ioctl = perf_compat_ioctl,
5411 .fasync = perf_fasync,
5417 * If there's data, ensure we set the poll() state and publish everything
5418 * to user-space before waking everybody up.
5421 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5423 /* only the parent has fasync state */
5425 event = event->parent;
5426 return &event->fasync;
5429 void perf_event_wakeup(struct perf_event *event)
5431 ring_buffer_wakeup(event);
5433 if (event->pending_kill) {
5434 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5435 event->pending_kill = 0;
5439 static void perf_pending_event(struct irq_work *entry)
5441 struct perf_event *event = container_of(entry,
5442 struct perf_event, pending);
5445 rctx = perf_swevent_get_recursion_context();
5447 * If we 'fail' here, that's OK, it means recursion is already disabled
5448 * and we won't recurse 'further'.
5451 if (event->pending_disable) {
5452 event->pending_disable = 0;
5453 perf_event_disable_local(event);
5456 if (event->pending_wakeup) {
5457 event->pending_wakeup = 0;
5458 perf_event_wakeup(event);
5462 perf_swevent_put_recursion_context(rctx);
5466 * We assume there is only KVM supporting the callbacks.
5467 * Later on, we might change it to a list if there is
5468 * another virtualization implementation supporting the callbacks.
5470 struct perf_guest_info_callbacks *perf_guest_cbs;
5472 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5474 perf_guest_cbs = cbs;
5477 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5479 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5481 perf_guest_cbs = NULL;
5484 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5487 perf_output_sample_regs(struct perf_output_handle *handle,
5488 struct pt_regs *regs, u64 mask)
5491 DECLARE_BITMAP(_mask, 64);
5493 bitmap_from_u64(_mask, mask);
5494 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5497 val = perf_reg_value(regs, bit);
5498 perf_output_put(handle, val);
5502 static void perf_sample_regs_user(struct perf_regs *regs_user,
5503 struct pt_regs *regs,
5504 struct pt_regs *regs_user_copy)
5506 if (user_mode(regs)) {
5507 regs_user->abi = perf_reg_abi(current);
5508 regs_user->regs = regs;
5509 } else if (current->mm) {
5510 perf_get_regs_user(regs_user, regs, regs_user_copy);
5512 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5513 regs_user->regs = NULL;
5517 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5518 struct pt_regs *regs)
5520 regs_intr->regs = regs;
5521 regs_intr->abi = perf_reg_abi(current);
5526 * Get remaining task size from user stack pointer.
5528 * It'd be better to take stack vma map and limit this more
5529 * precisly, but there's no way to get it safely under interrupt,
5530 * so using TASK_SIZE as limit.
5532 static u64 perf_ustack_task_size(struct pt_regs *regs)
5534 unsigned long addr = perf_user_stack_pointer(regs);
5536 if (!addr || addr >= TASK_SIZE)
5539 return TASK_SIZE - addr;
5543 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5544 struct pt_regs *regs)
5548 /* No regs, no stack pointer, no dump. */
5553 * Check if we fit in with the requested stack size into the:
5555 * If we don't, we limit the size to the TASK_SIZE.
5557 * - remaining sample size
5558 * If we don't, we customize the stack size to
5559 * fit in to the remaining sample size.
5562 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5563 stack_size = min(stack_size, (u16) task_size);
5565 /* Current header size plus static size and dynamic size. */
5566 header_size += 2 * sizeof(u64);
5568 /* Do we fit in with the current stack dump size? */
5569 if ((u16) (header_size + stack_size) < header_size) {
5571 * If we overflow the maximum size for the sample,
5572 * we customize the stack dump size to fit in.
5574 stack_size = USHRT_MAX - header_size - sizeof(u64);
5575 stack_size = round_up(stack_size, sizeof(u64));
5582 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5583 struct pt_regs *regs)
5585 /* Case of a kernel thread, nothing to dump */
5588 perf_output_put(handle, size);
5597 * - the size requested by user or the best one we can fit
5598 * in to the sample max size
5600 * - user stack dump data
5602 * - the actual dumped size
5606 perf_output_put(handle, dump_size);
5609 sp = perf_user_stack_pointer(regs);
5610 rem = __output_copy_user(handle, (void *) sp, dump_size);
5611 dyn_size = dump_size - rem;
5613 perf_output_skip(handle, rem);
5616 perf_output_put(handle, dyn_size);
5620 static void __perf_event_header__init_id(struct perf_event_header *header,
5621 struct perf_sample_data *data,
5622 struct perf_event *event)
5624 u64 sample_type = event->attr.sample_type;
5626 data->type = sample_type;
5627 header->size += event->id_header_size;
5629 if (sample_type & PERF_SAMPLE_TID) {
5630 /* namespace issues */
5631 data->tid_entry.pid = perf_event_pid(event, current);
5632 data->tid_entry.tid = perf_event_tid(event, current);
5635 if (sample_type & PERF_SAMPLE_TIME)
5636 data->time = perf_event_clock(event);
5638 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5639 data->id = primary_event_id(event);
5641 if (sample_type & PERF_SAMPLE_STREAM_ID)
5642 data->stream_id = event->id;
5644 if (sample_type & PERF_SAMPLE_CPU) {
5645 data->cpu_entry.cpu = raw_smp_processor_id();
5646 data->cpu_entry.reserved = 0;
5650 void perf_event_header__init_id(struct perf_event_header *header,
5651 struct perf_sample_data *data,
5652 struct perf_event *event)
5654 if (event->attr.sample_id_all)
5655 __perf_event_header__init_id(header, data, event);
5658 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5659 struct perf_sample_data *data)
5661 u64 sample_type = data->type;
5663 if (sample_type & PERF_SAMPLE_TID)
5664 perf_output_put(handle, data->tid_entry);
5666 if (sample_type & PERF_SAMPLE_TIME)
5667 perf_output_put(handle, data->time);
5669 if (sample_type & PERF_SAMPLE_ID)
5670 perf_output_put(handle, data->id);
5672 if (sample_type & PERF_SAMPLE_STREAM_ID)
5673 perf_output_put(handle, data->stream_id);
5675 if (sample_type & PERF_SAMPLE_CPU)
5676 perf_output_put(handle, data->cpu_entry);
5678 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5679 perf_output_put(handle, data->id);
5682 void perf_event__output_id_sample(struct perf_event *event,
5683 struct perf_output_handle *handle,
5684 struct perf_sample_data *sample)
5686 if (event->attr.sample_id_all)
5687 __perf_event__output_id_sample(handle, sample);
5690 static void perf_output_read_one(struct perf_output_handle *handle,
5691 struct perf_event *event,
5692 u64 enabled, u64 running)
5694 u64 read_format = event->attr.read_format;
5698 values[n++] = perf_event_count(event);
5699 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5700 values[n++] = enabled +
5701 atomic64_read(&event->child_total_time_enabled);
5703 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5704 values[n++] = running +
5705 atomic64_read(&event->child_total_time_running);
5707 if (read_format & PERF_FORMAT_ID)
5708 values[n++] = primary_event_id(event);
5710 __output_copy(handle, values, n * sizeof(u64));
5713 static void perf_output_read_group(struct perf_output_handle *handle,
5714 struct perf_event *event,
5715 u64 enabled, u64 running)
5717 struct perf_event *leader = event->group_leader, *sub;
5718 u64 read_format = event->attr.read_format;
5722 values[n++] = 1 + leader->nr_siblings;
5724 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5725 values[n++] = enabled;
5727 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5728 values[n++] = running;
5730 if (leader != event)
5731 leader->pmu->read(leader);
5733 values[n++] = perf_event_count(leader);
5734 if (read_format & PERF_FORMAT_ID)
5735 values[n++] = primary_event_id(leader);
5737 __output_copy(handle, values, n * sizeof(u64));
5739 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5742 if ((sub != event) &&
5743 (sub->state == PERF_EVENT_STATE_ACTIVE))
5744 sub->pmu->read(sub);
5746 values[n++] = perf_event_count(sub);
5747 if (read_format & PERF_FORMAT_ID)
5748 values[n++] = primary_event_id(sub);
5750 __output_copy(handle, values, n * sizeof(u64));
5754 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5755 PERF_FORMAT_TOTAL_TIME_RUNNING)
5758 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5760 * The problem is that its both hard and excessively expensive to iterate the
5761 * child list, not to mention that its impossible to IPI the children running
5762 * on another CPU, from interrupt/NMI context.
5764 static void perf_output_read(struct perf_output_handle *handle,
5765 struct perf_event *event)
5767 u64 enabled = 0, running = 0, now;
5768 u64 read_format = event->attr.read_format;
5771 * compute total_time_enabled, total_time_running
5772 * based on snapshot values taken when the event
5773 * was last scheduled in.
5775 * we cannot simply called update_context_time()
5776 * because of locking issue as we are called in
5779 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5780 calc_timer_values(event, &now, &enabled, &running);
5782 if (event->attr.read_format & PERF_FORMAT_GROUP)
5783 perf_output_read_group(handle, event, enabled, running);
5785 perf_output_read_one(handle, event, enabled, running);
5788 void perf_output_sample(struct perf_output_handle *handle,
5789 struct perf_event_header *header,
5790 struct perf_sample_data *data,
5791 struct perf_event *event)
5793 u64 sample_type = data->type;
5795 perf_output_put(handle, *header);
5797 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5798 perf_output_put(handle, data->id);
5800 if (sample_type & PERF_SAMPLE_IP)
5801 perf_output_put(handle, data->ip);
5803 if (sample_type & PERF_SAMPLE_TID)
5804 perf_output_put(handle, data->tid_entry);
5806 if (sample_type & PERF_SAMPLE_TIME)
5807 perf_output_put(handle, data->time);
5809 if (sample_type & PERF_SAMPLE_ADDR)
5810 perf_output_put(handle, data->addr);
5812 if (sample_type & PERF_SAMPLE_ID)
5813 perf_output_put(handle, data->id);
5815 if (sample_type & PERF_SAMPLE_STREAM_ID)
5816 perf_output_put(handle, data->stream_id);
5818 if (sample_type & PERF_SAMPLE_CPU)
5819 perf_output_put(handle, data->cpu_entry);
5821 if (sample_type & PERF_SAMPLE_PERIOD)
5822 perf_output_put(handle, data->period);
5824 if (sample_type & PERF_SAMPLE_READ)
5825 perf_output_read(handle, event);
5827 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5830 size += data->callchain->nr;
5831 size *= sizeof(u64);
5832 __output_copy(handle, data->callchain, size);
5835 if (sample_type & PERF_SAMPLE_RAW) {
5836 struct perf_raw_record *raw = data->raw;
5839 struct perf_raw_frag *frag = &raw->frag;
5841 perf_output_put(handle, raw->size);
5844 __output_custom(handle, frag->copy,
5845 frag->data, frag->size);
5847 __output_copy(handle, frag->data,
5850 if (perf_raw_frag_last(frag))
5855 __output_skip(handle, NULL, frag->pad);
5861 .size = sizeof(u32),
5864 perf_output_put(handle, raw);
5868 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5869 if (data->br_stack) {
5872 size = data->br_stack->nr
5873 * sizeof(struct perf_branch_entry);
5875 perf_output_put(handle, data->br_stack->nr);
5876 perf_output_copy(handle, data->br_stack->entries, size);
5879 * we always store at least the value of nr
5882 perf_output_put(handle, nr);
5886 if (sample_type & PERF_SAMPLE_REGS_USER) {
5887 u64 abi = data->regs_user.abi;
5890 * If there are no regs to dump, notice it through
5891 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5893 perf_output_put(handle, abi);
5896 u64 mask = event->attr.sample_regs_user;
5897 perf_output_sample_regs(handle,
5898 data->regs_user.regs,
5903 if (sample_type & PERF_SAMPLE_STACK_USER) {
5904 perf_output_sample_ustack(handle,
5905 data->stack_user_size,
5906 data->regs_user.regs);
5909 if (sample_type & PERF_SAMPLE_WEIGHT)
5910 perf_output_put(handle, data->weight);
5912 if (sample_type & PERF_SAMPLE_DATA_SRC)
5913 perf_output_put(handle, data->data_src.val);
5915 if (sample_type & PERF_SAMPLE_TRANSACTION)
5916 perf_output_put(handle, data->txn);
5918 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5919 u64 abi = data->regs_intr.abi;
5921 * If there are no regs to dump, notice it through
5922 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5924 perf_output_put(handle, abi);
5927 u64 mask = event->attr.sample_regs_intr;
5929 perf_output_sample_regs(handle,
5930 data->regs_intr.regs,
5935 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
5936 perf_output_put(handle, data->phys_addr);
5938 if (!event->attr.watermark) {
5939 int wakeup_events = event->attr.wakeup_events;
5941 if (wakeup_events) {
5942 struct ring_buffer *rb = handle->rb;
5943 int events = local_inc_return(&rb->events);
5945 if (events >= wakeup_events) {
5946 local_sub(wakeup_events, &rb->events);
5947 local_inc(&rb->wakeup);
5953 static u64 perf_virt_to_phys(u64 virt)
5956 struct page *p = NULL;
5961 if (virt >= TASK_SIZE) {
5962 /* If it's vmalloc()d memory, leave phys_addr as 0 */
5963 if (virt_addr_valid((void *)(uintptr_t)virt) &&
5964 !(virt >= VMALLOC_START && virt < VMALLOC_END))
5965 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
5968 * Walking the pages tables for user address.
5969 * Interrupts are disabled, so it prevents any tear down
5970 * of the page tables.
5971 * Try IRQ-safe __get_user_pages_fast first.
5972 * If failed, leave phys_addr as 0.
5974 if ((current->mm != NULL) &&
5975 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
5976 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
5985 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
5987 static struct perf_callchain_entry *
5988 perf_callchain(struct perf_event *event, struct pt_regs *regs)
5990 bool kernel = !event->attr.exclude_callchain_kernel;
5991 bool user = !event->attr.exclude_callchain_user;
5992 /* Disallow cross-task user callchains. */
5993 bool crosstask = event->ctx->task && event->ctx->task != current;
5994 const u32 max_stack = event->attr.sample_max_stack;
5995 struct perf_callchain_entry *callchain;
5997 if (!kernel && !user)
5998 return &__empty_callchain;
6000 callchain = get_perf_callchain(regs, 0, kernel, user,
6001 max_stack, crosstask, true);
6002 return callchain ?: &__empty_callchain;
6005 void perf_prepare_sample(struct perf_event_header *header,
6006 struct perf_sample_data *data,
6007 struct perf_event *event,
6008 struct pt_regs *regs)
6010 u64 sample_type = event->attr.sample_type;
6012 header->type = PERF_RECORD_SAMPLE;
6013 header->size = sizeof(*header) + event->header_size;
6016 header->misc |= perf_misc_flags(regs);
6018 __perf_event_header__init_id(header, data, event);
6020 if (sample_type & PERF_SAMPLE_IP)
6021 data->ip = perf_instruction_pointer(regs);
6023 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6026 data->callchain = perf_callchain(event, regs);
6027 size += data->callchain->nr;
6029 header->size += size * sizeof(u64);
6032 if (sample_type & PERF_SAMPLE_RAW) {
6033 struct perf_raw_record *raw = data->raw;
6037 struct perf_raw_frag *frag = &raw->frag;
6042 if (perf_raw_frag_last(frag))
6047 size = round_up(sum + sizeof(u32), sizeof(u64));
6048 raw->size = size - sizeof(u32);
6049 frag->pad = raw->size - sum;
6054 header->size += size;
6057 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6058 int size = sizeof(u64); /* nr */
6059 if (data->br_stack) {
6060 size += data->br_stack->nr
6061 * sizeof(struct perf_branch_entry);
6063 header->size += size;
6066 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6067 perf_sample_regs_user(&data->regs_user, regs,
6068 &data->regs_user_copy);
6070 if (sample_type & PERF_SAMPLE_REGS_USER) {
6071 /* regs dump ABI info */
6072 int size = sizeof(u64);
6074 if (data->regs_user.regs) {
6075 u64 mask = event->attr.sample_regs_user;
6076 size += hweight64(mask) * sizeof(u64);
6079 header->size += size;
6082 if (sample_type & PERF_SAMPLE_STACK_USER) {
6084 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6085 * processed as the last one or have additional check added
6086 * in case new sample type is added, because we could eat
6087 * up the rest of the sample size.
6089 u16 stack_size = event->attr.sample_stack_user;
6090 u16 size = sizeof(u64);
6092 stack_size = perf_sample_ustack_size(stack_size, header->size,
6093 data->regs_user.regs);
6096 * If there is something to dump, add space for the dump
6097 * itself and for the field that tells the dynamic size,
6098 * which is how many have been actually dumped.
6101 size += sizeof(u64) + stack_size;
6103 data->stack_user_size = stack_size;
6104 header->size += size;
6107 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6108 /* regs dump ABI info */
6109 int size = sizeof(u64);
6111 perf_sample_regs_intr(&data->regs_intr, regs);
6113 if (data->regs_intr.regs) {
6114 u64 mask = event->attr.sample_regs_intr;
6116 size += hweight64(mask) * sizeof(u64);
6119 header->size += size;
6122 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6123 data->phys_addr = perf_virt_to_phys(data->addr);
6126 static void __always_inline
6127 __perf_event_output(struct perf_event *event,
6128 struct perf_sample_data *data,
6129 struct pt_regs *regs,
6130 int (*output_begin)(struct perf_output_handle *,
6131 struct perf_event *,
6134 struct perf_output_handle handle;
6135 struct perf_event_header header;
6137 /* protect the callchain buffers */
6140 perf_prepare_sample(&header, data, event, regs);
6142 if (output_begin(&handle, event, header.size))
6145 perf_output_sample(&handle, &header, data, event);
6147 perf_output_end(&handle);
6154 perf_event_output_forward(struct perf_event *event,
6155 struct perf_sample_data *data,
6156 struct pt_regs *regs)
6158 __perf_event_output(event, data, regs, perf_output_begin_forward);
6162 perf_event_output_backward(struct perf_event *event,
6163 struct perf_sample_data *data,
6164 struct pt_regs *regs)
6166 __perf_event_output(event, data, regs, perf_output_begin_backward);
6170 perf_event_output(struct perf_event *event,
6171 struct perf_sample_data *data,
6172 struct pt_regs *regs)
6174 __perf_event_output(event, data, regs, perf_output_begin);
6181 struct perf_read_event {
6182 struct perf_event_header header;
6189 perf_event_read_event(struct perf_event *event,
6190 struct task_struct *task)
6192 struct perf_output_handle handle;
6193 struct perf_sample_data sample;
6194 struct perf_read_event read_event = {
6196 .type = PERF_RECORD_READ,
6198 .size = sizeof(read_event) + event->read_size,
6200 .pid = perf_event_pid(event, task),
6201 .tid = perf_event_tid(event, task),
6205 perf_event_header__init_id(&read_event.header, &sample, event);
6206 ret = perf_output_begin(&handle, event, read_event.header.size);
6210 perf_output_put(&handle, read_event);
6211 perf_output_read(&handle, event);
6212 perf_event__output_id_sample(event, &handle, &sample);
6214 perf_output_end(&handle);
6217 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6220 perf_iterate_ctx(struct perf_event_context *ctx,
6221 perf_iterate_f output,
6222 void *data, bool all)
6224 struct perf_event *event;
6226 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6228 if (event->state < PERF_EVENT_STATE_INACTIVE)
6230 if (!event_filter_match(event))
6234 output(event, data);
6238 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6240 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6241 struct perf_event *event;
6243 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6245 * Skip events that are not fully formed yet; ensure that
6246 * if we observe event->ctx, both event and ctx will be
6247 * complete enough. See perf_install_in_context().
6249 if (!smp_load_acquire(&event->ctx))
6252 if (event->state < PERF_EVENT_STATE_INACTIVE)
6254 if (!event_filter_match(event))
6256 output(event, data);
6261 * Iterate all events that need to receive side-band events.
6263 * For new callers; ensure that account_pmu_sb_event() includes
6264 * your event, otherwise it might not get delivered.
6267 perf_iterate_sb(perf_iterate_f output, void *data,
6268 struct perf_event_context *task_ctx)
6270 struct perf_event_context *ctx;
6277 * If we have task_ctx != NULL we only notify the task context itself.
6278 * The task_ctx is set only for EXIT events before releasing task
6282 perf_iterate_ctx(task_ctx, output, data, false);
6286 perf_iterate_sb_cpu(output, data);
6288 for_each_task_context_nr(ctxn) {
6289 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6291 perf_iterate_ctx(ctx, output, data, false);
6299 * Clear all file-based filters at exec, they'll have to be
6300 * re-instated when/if these objects are mmapped again.
6302 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6304 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6305 struct perf_addr_filter *filter;
6306 unsigned int restart = 0, count = 0;
6307 unsigned long flags;
6309 if (!has_addr_filter(event))
6312 raw_spin_lock_irqsave(&ifh->lock, flags);
6313 list_for_each_entry(filter, &ifh->list, entry) {
6314 if (filter->inode) {
6315 event->addr_filters_offs[count] = 0;
6323 event->addr_filters_gen++;
6324 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6327 perf_event_stop(event, 1);
6330 void perf_event_exec(void)
6332 struct perf_event_context *ctx;
6336 for_each_task_context_nr(ctxn) {
6337 ctx = current->perf_event_ctxp[ctxn];
6341 perf_event_enable_on_exec(ctxn);
6343 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6349 struct remote_output {
6350 struct ring_buffer *rb;
6354 static void __perf_event_output_stop(struct perf_event *event, void *data)
6356 struct perf_event *parent = event->parent;
6357 struct remote_output *ro = data;
6358 struct ring_buffer *rb = ro->rb;
6359 struct stop_event_data sd = {
6363 if (!has_aux(event))
6370 * In case of inheritance, it will be the parent that links to the
6371 * ring-buffer, but it will be the child that's actually using it.
6373 * We are using event::rb to determine if the event should be stopped,
6374 * however this may race with ring_buffer_attach() (through set_output),
6375 * which will make us skip the event that actually needs to be stopped.
6376 * So ring_buffer_attach() has to stop an aux event before re-assigning
6379 if (rcu_dereference(parent->rb) == rb)
6380 ro->err = __perf_event_stop(&sd);
6383 static int __perf_pmu_output_stop(void *info)
6385 struct perf_event *event = info;
6386 struct pmu *pmu = event->pmu;
6387 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6388 struct remote_output ro = {
6393 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6394 if (cpuctx->task_ctx)
6395 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6402 static void perf_pmu_output_stop(struct perf_event *event)
6404 struct perf_event *iter;
6409 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6411 * For per-CPU events, we need to make sure that neither they
6412 * nor their children are running; for cpu==-1 events it's
6413 * sufficient to stop the event itself if it's active, since
6414 * it can't have children.
6418 cpu = READ_ONCE(iter->oncpu);
6423 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6424 if (err == -EAGAIN) {
6433 * task tracking -- fork/exit
6435 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6438 struct perf_task_event {
6439 struct task_struct *task;
6440 struct perf_event_context *task_ctx;
6443 struct perf_event_header header;
6453 static int perf_event_task_match(struct perf_event *event)
6455 return event->attr.comm || event->attr.mmap ||
6456 event->attr.mmap2 || event->attr.mmap_data ||
6460 static void perf_event_task_output(struct perf_event *event,
6463 struct perf_task_event *task_event = data;
6464 struct perf_output_handle handle;
6465 struct perf_sample_data sample;
6466 struct task_struct *task = task_event->task;
6467 int ret, size = task_event->event_id.header.size;
6469 if (!perf_event_task_match(event))
6472 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6474 ret = perf_output_begin(&handle, event,
6475 task_event->event_id.header.size);
6479 task_event->event_id.pid = perf_event_pid(event, task);
6480 task_event->event_id.ppid = perf_event_pid(event, current);
6482 task_event->event_id.tid = perf_event_tid(event, task);
6483 task_event->event_id.ptid = perf_event_tid(event, current);
6485 task_event->event_id.time = perf_event_clock(event);
6487 perf_output_put(&handle, task_event->event_id);
6489 perf_event__output_id_sample(event, &handle, &sample);
6491 perf_output_end(&handle);
6493 task_event->event_id.header.size = size;
6496 static void perf_event_task(struct task_struct *task,
6497 struct perf_event_context *task_ctx,
6500 struct perf_task_event task_event;
6502 if (!atomic_read(&nr_comm_events) &&
6503 !atomic_read(&nr_mmap_events) &&
6504 !atomic_read(&nr_task_events))
6507 task_event = (struct perf_task_event){
6509 .task_ctx = task_ctx,
6512 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6514 .size = sizeof(task_event.event_id),
6524 perf_iterate_sb(perf_event_task_output,
6529 void perf_event_fork(struct task_struct *task)
6531 perf_event_task(task, NULL, 1);
6532 perf_event_namespaces(task);
6539 struct perf_comm_event {
6540 struct task_struct *task;
6545 struct perf_event_header header;
6552 static int perf_event_comm_match(struct perf_event *event)
6554 return event->attr.comm;
6557 static void perf_event_comm_output(struct perf_event *event,
6560 struct perf_comm_event *comm_event = data;
6561 struct perf_output_handle handle;
6562 struct perf_sample_data sample;
6563 int size = comm_event->event_id.header.size;
6566 if (!perf_event_comm_match(event))
6569 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6570 ret = perf_output_begin(&handle, event,
6571 comm_event->event_id.header.size);
6576 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6577 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6579 perf_output_put(&handle, comm_event->event_id);
6580 __output_copy(&handle, comm_event->comm,
6581 comm_event->comm_size);
6583 perf_event__output_id_sample(event, &handle, &sample);
6585 perf_output_end(&handle);
6587 comm_event->event_id.header.size = size;
6590 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6592 char comm[TASK_COMM_LEN];
6595 memset(comm, 0, sizeof(comm));
6596 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6597 size = ALIGN(strlen(comm)+1, sizeof(u64));
6599 comm_event->comm = comm;
6600 comm_event->comm_size = size;
6602 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6604 perf_iterate_sb(perf_event_comm_output,
6609 void perf_event_comm(struct task_struct *task, bool exec)
6611 struct perf_comm_event comm_event;
6613 if (!atomic_read(&nr_comm_events))
6616 comm_event = (struct perf_comm_event){
6622 .type = PERF_RECORD_COMM,
6623 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6631 perf_event_comm_event(&comm_event);
6635 * namespaces tracking
6638 struct perf_namespaces_event {
6639 struct task_struct *task;
6642 struct perf_event_header header;
6647 struct perf_ns_link_info link_info[NR_NAMESPACES];
6651 static int perf_event_namespaces_match(struct perf_event *event)
6653 return event->attr.namespaces;
6656 static void perf_event_namespaces_output(struct perf_event *event,
6659 struct perf_namespaces_event *namespaces_event = data;
6660 struct perf_output_handle handle;
6661 struct perf_sample_data sample;
6662 u16 header_size = namespaces_event->event_id.header.size;
6665 if (!perf_event_namespaces_match(event))
6668 perf_event_header__init_id(&namespaces_event->event_id.header,
6670 ret = perf_output_begin(&handle, event,
6671 namespaces_event->event_id.header.size);
6675 namespaces_event->event_id.pid = perf_event_pid(event,
6676 namespaces_event->task);
6677 namespaces_event->event_id.tid = perf_event_tid(event,
6678 namespaces_event->task);
6680 perf_output_put(&handle, namespaces_event->event_id);
6682 perf_event__output_id_sample(event, &handle, &sample);
6684 perf_output_end(&handle);
6686 namespaces_event->event_id.header.size = header_size;
6689 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6690 struct task_struct *task,
6691 const struct proc_ns_operations *ns_ops)
6693 struct path ns_path;
6694 struct inode *ns_inode;
6697 error = ns_get_path(&ns_path, task, ns_ops);
6699 ns_inode = ns_path.dentry->d_inode;
6700 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6701 ns_link_info->ino = ns_inode->i_ino;
6706 void perf_event_namespaces(struct task_struct *task)
6708 struct perf_namespaces_event namespaces_event;
6709 struct perf_ns_link_info *ns_link_info;
6711 if (!atomic_read(&nr_namespaces_events))
6714 namespaces_event = (struct perf_namespaces_event){
6718 .type = PERF_RECORD_NAMESPACES,
6720 .size = sizeof(namespaces_event.event_id),
6724 .nr_namespaces = NR_NAMESPACES,
6725 /* .link_info[NR_NAMESPACES] */
6729 ns_link_info = namespaces_event.event_id.link_info;
6731 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6732 task, &mntns_operations);
6734 #ifdef CONFIG_USER_NS
6735 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6736 task, &userns_operations);
6738 #ifdef CONFIG_NET_NS
6739 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6740 task, &netns_operations);
6742 #ifdef CONFIG_UTS_NS
6743 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6744 task, &utsns_operations);
6746 #ifdef CONFIG_IPC_NS
6747 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6748 task, &ipcns_operations);
6750 #ifdef CONFIG_PID_NS
6751 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6752 task, &pidns_operations);
6754 #ifdef CONFIG_CGROUPS
6755 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6756 task, &cgroupns_operations);
6759 perf_iterate_sb(perf_event_namespaces_output,
6768 struct perf_mmap_event {
6769 struct vm_area_struct *vma;
6771 const char *file_name;
6779 struct perf_event_header header;
6789 static int perf_event_mmap_match(struct perf_event *event,
6792 struct perf_mmap_event *mmap_event = data;
6793 struct vm_area_struct *vma = mmap_event->vma;
6794 int executable = vma->vm_flags & VM_EXEC;
6796 return (!executable && event->attr.mmap_data) ||
6797 (executable && (event->attr.mmap || event->attr.mmap2));
6800 static void perf_event_mmap_output(struct perf_event *event,
6803 struct perf_mmap_event *mmap_event = data;
6804 struct perf_output_handle handle;
6805 struct perf_sample_data sample;
6806 int size = mmap_event->event_id.header.size;
6809 if (!perf_event_mmap_match(event, data))
6812 if (event->attr.mmap2) {
6813 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6814 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6815 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6816 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6817 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6818 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6819 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6822 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6823 ret = perf_output_begin(&handle, event,
6824 mmap_event->event_id.header.size);
6828 mmap_event->event_id.pid = perf_event_pid(event, current);
6829 mmap_event->event_id.tid = perf_event_tid(event, current);
6831 perf_output_put(&handle, mmap_event->event_id);
6833 if (event->attr.mmap2) {
6834 perf_output_put(&handle, mmap_event->maj);
6835 perf_output_put(&handle, mmap_event->min);
6836 perf_output_put(&handle, mmap_event->ino);
6837 perf_output_put(&handle, mmap_event->ino_generation);
6838 perf_output_put(&handle, mmap_event->prot);
6839 perf_output_put(&handle, mmap_event->flags);
6842 __output_copy(&handle, mmap_event->file_name,
6843 mmap_event->file_size);
6845 perf_event__output_id_sample(event, &handle, &sample);
6847 perf_output_end(&handle);
6849 mmap_event->event_id.header.size = size;
6852 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6854 struct vm_area_struct *vma = mmap_event->vma;
6855 struct file *file = vma->vm_file;
6856 int maj = 0, min = 0;
6857 u64 ino = 0, gen = 0;
6858 u32 prot = 0, flags = 0;
6864 if (vma->vm_flags & VM_READ)
6866 if (vma->vm_flags & VM_WRITE)
6868 if (vma->vm_flags & VM_EXEC)
6871 if (vma->vm_flags & VM_MAYSHARE)
6874 flags = MAP_PRIVATE;
6876 if (vma->vm_flags & VM_DENYWRITE)
6877 flags |= MAP_DENYWRITE;
6878 if (vma->vm_flags & VM_MAYEXEC)
6879 flags |= MAP_EXECUTABLE;
6880 if (vma->vm_flags & VM_LOCKED)
6881 flags |= MAP_LOCKED;
6882 if (vma->vm_flags & VM_HUGETLB)
6883 flags |= MAP_HUGETLB;
6886 struct inode *inode;
6889 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6895 * d_path() works from the end of the rb backwards, so we
6896 * need to add enough zero bytes after the string to handle
6897 * the 64bit alignment we do later.
6899 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6904 inode = file_inode(vma->vm_file);
6905 dev = inode->i_sb->s_dev;
6907 gen = inode->i_generation;
6913 if (vma->vm_ops && vma->vm_ops->name) {
6914 name = (char *) vma->vm_ops->name(vma);
6919 name = (char *)arch_vma_name(vma);
6923 if (vma->vm_start <= vma->vm_mm->start_brk &&
6924 vma->vm_end >= vma->vm_mm->brk) {
6928 if (vma->vm_start <= vma->vm_mm->start_stack &&
6929 vma->vm_end >= vma->vm_mm->start_stack) {
6939 strlcpy(tmp, name, sizeof(tmp));
6943 * Since our buffer works in 8 byte units we need to align our string
6944 * size to a multiple of 8. However, we must guarantee the tail end is
6945 * zero'd out to avoid leaking random bits to userspace.
6947 size = strlen(name)+1;
6948 while (!IS_ALIGNED(size, sizeof(u64)))
6949 name[size++] = '\0';
6951 mmap_event->file_name = name;
6952 mmap_event->file_size = size;
6953 mmap_event->maj = maj;
6954 mmap_event->min = min;
6955 mmap_event->ino = ino;
6956 mmap_event->ino_generation = gen;
6957 mmap_event->prot = prot;
6958 mmap_event->flags = flags;
6960 if (!(vma->vm_flags & VM_EXEC))
6961 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6963 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6965 perf_iterate_sb(perf_event_mmap_output,
6973 * Check whether inode and address range match filter criteria.
6975 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6976 struct file *file, unsigned long offset,
6979 if (filter->inode != file_inode(file))
6982 if (filter->offset > offset + size)
6985 if (filter->offset + filter->size < offset)
6991 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6993 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6994 struct vm_area_struct *vma = data;
6995 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6996 struct file *file = vma->vm_file;
6997 struct perf_addr_filter *filter;
6998 unsigned int restart = 0, count = 0;
7000 if (!has_addr_filter(event))
7006 raw_spin_lock_irqsave(&ifh->lock, flags);
7007 list_for_each_entry(filter, &ifh->list, entry) {
7008 if (perf_addr_filter_match(filter, file, off,
7009 vma->vm_end - vma->vm_start)) {
7010 event->addr_filters_offs[count] = vma->vm_start;
7018 event->addr_filters_gen++;
7019 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7022 perf_event_stop(event, 1);
7026 * Adjust all task's events' filters to the new vma
7028 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7030 struct perf_event_context *ctx;
7034 * Data tracing isn't supported yet and as such there is no need
7035 * to keep track of anything that isn't related to executable code:
7037 if (!(vma->vm_flags & VM_EXEC))
7041 for_each_task_context_nr(ctxn) {
7042 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7046 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7051 void perf_event_mmap(struct vm_area_struct *vma)
7053 struct perf_mmap_event mmap_event;
7055 if (!atomic_read(&nr_mmap_events))
7058 mmap_event = (struct perf_mmap_event){
7064 .type = PERF_RECORD_MMAP,
7065 .misc = PERF_RECORD_MISC_USER,
7070 .start = vma->vm_start,
7071 .len = vma->vm_end - vma->vm_start,
7072 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7074 /* .maj (attr_mmap2 only) */
7075 /* .min (attr_mmap2 only) */
7076 /* .ino (attr_mmap2 only) */
7077 /* .ino_generation (attr_mmap2 only) */
7078 /* .prot (attr_mmap2 only) */
7079 /* .flags (attr_mmap2 only) */
7082 perf_addr_filters_adjust(vma);
7083 perf_event_mmap_event(&mmap_event);
7086 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7087 unsigned long size, u64 flags)
7089 struct perf_output_handle handle;
7090 struct perf_sample_data sample;
7091 struct perf_aux_event {
7092 struct perf_event_header header;
7098 .type = PERF_RECORD_AUX,
7100 .size = sizeof(rec),
7108 perf_event_header__init_id(&rec.header, &sample, event);
7109 ret = perf_output_begin(&handle, event, rec.header.size);
7114 perf_output_put(&handle, rec);
7115 perf_event__output_id_sample(event, &handle, &sample);
7117 perf_output_end(&handle);
7121 * Lost/dropped samples logging
7123 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7125 struct perf_output_handle handle;
7126 struct perf_sample_data sample;
7130 struct perf_event_header header;
7132 } lost_samples_event = {
7134 .type = PERF_RECORD_LOST_SAMPLES,
7136 .size = sizeof(lost_samples_event),
7141 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7143 ret = perf_output_begin(&handle, event,
7144 lost_samples_event.header.size);
7148 perf_output_put(&handle, lost_samples_event);
7149 perf_event__output_id_sample(event, &handle, &sample);
7150 perf_output_end(&handle);
7154 * context_switch tracking
7157 struct perf_switch_event {
7158 struct task_struct *task;
7159 struct task_struct *next_prev;
7162 struct perf_event_header header;
7168 static int perf_event_switch_match(struct perf_event *event)
7170 return event->attr.context_switch;
7173 static void perf_event_switch_output(struct perf_event *event, void *data)
7175 struct perf_switch_event *se = data;
7176 struct perf_output_handle handle;
7177 struct perf_sample_data sample;
7180 if (!perf_event_switch_match(event))
7183 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7184 if (event->ctx->task) {
7185 se->event_id.header.type = PERF_RECORD_SWITCH;
7186 se->event_id.header.size = sizeof(se->event_id.header);
7188 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7189 se->event_id.header.size = sizeof(se->event_id);
7190 se->event_id.next_prev_pid =
7191 perf_event_pid(event, se->next_prev);
7192 se->event_id.next_prev_tid =
7193 perf_event_tid(event, se->next_prev);
7196 perf_event_header__init_id(&se->event_id.header, &sample, event);
7198 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7202 if (event->ctx->task)
7203 perf_output_put(&handle, se->event_id.header);
7205 perf_output_put(&handle, se->event_id);
7207 perf_event__output_id_sample(event, &handle, &sample);
7209 perf_output_end(&handle);
7212 static void perf_event_switch(struct task_struct *task,
7213 struct task_struct *next_prev, bool sched_in)
7215 struct perf_switch_event switch_event;
7217 /* N.B. caller checks nr_switch_events != 0 */
7219 switch_event = (struct perf_switch_event){
7221 .next_prev = next_prev,
7225 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7228 /* .next_prev_pid */
7229 /* .next_prev_tid */
7233 perf_iterate_sb(perf_event_switch_output,
7239 * IRQ throttle logging
7242 static void perf_log_throttle(struct perf_event *event, int enable)
7244 struct perf_output_handle handle;
7245 struct perf_sample_data sample;
7249 struct perf_event_header header;
7253 } throttle_event = {
7255 .type = PERF_RECORD_THROTTLE,
7257 .size = sizeof(throttle_event),
7259 .time = perf_event_clock(event),
7260 .id = primary_event_id(event),
7261 .stream_id = event->id,
7265 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7267 perf_event_header__init_id(&throttle_event.header, &sample, event);
7269 ret = perf_output_begin(&handle, event,
7270 throttle_event.header.size);
7274 perf_output_put(&handle, throttle_event);
7275 perf_event__output_id_sample(event, &handle, &sample);
7276 perf_output_end(&handle);
7279 void perf_event_itrace_started(struct perf_event *event)
7281 event->attach_state |= PERF_ATTACH_ITRACE;
7284 static void perf_log_itrace_start(struct perf_event *event)
7286 struct perf_output_handle handle;
7287 struct perf_sample_data sample;
7288 struct perf_aux_event {
7289 struct perf_event_header header;
7296 event = event->parent;
7298 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7299 event->attach_state & PERF_ATTACH_ITRACE)
7302 rec.header.type = PERF_RECORD_ITRACE_START;
7303 rec.header.misc = 0;
7304 rec.header.size = sizeof(rec);
7305 rec.pid = perf_event_pid(event, current);
7306 rec.tid = perf_event_tid(event, current);
7308 perf_event_header__init_id(&rec.header, &sample, event);
7309 ret = perf_output_begin(&handle, event, rec.header.size);
7314 perf_output_put(&handle, rec);
7315 perf_event__output_id_sample(event, &handle, &sample);
7317 perf_output_end(&handle);
7321 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7323 struct hw_perf_event *hwc = &event->hw;
7327 seq = __this_cpu_read(perf_throttled_seq);
7328 if (seq != hwc->interrupts_seq) {
7329 hwc->interrupts_seq = seq;
7330 hwc->interrupts = 1;
7333 if (unlikely(throttle
7334 && hwc->interrupts >= max_samples_per_tick)) {
7335 __this_cpu_inc(perf_throttled_count);
7336 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7337 hwc->interrupts = MAX_INTERRUPTS;
7338 perf_log_throttle(event, 0);
7343 if (event->attr.freq) {
7344 u64 now = perf_clock();
7345 s64 delta = now - hwc->freq_time_stamp;
7347 hwc->freq_time_stamp = now;
7349 if (delta > 0 && delta < 2*TICK_NSEC)
7350 perf_adjust_period(event, delta, hwc->last_period, true);
7356 int perf_event_account_interrupt(struct perf_event *event)
7358 return __perf_event_account_interrupt(event, 1);
7362 * Generic event overflow handling, sampling.
7365 static int __perf_event_overflow(struct perf_event *event,
7366 int throttle, struct perf_sample_data *data,
7367 struct pt_regs *regs)
7369 int events = atomic_read(&event->event_limit);
7373 * Non-sampling counters might still use the PMI to fold short
7374 * hardware counters, ignore those.
7376 if (unlikely(!is_sampling_event(event)))
7379 ret = __perf_event_account_interrupt(event, throttle);
7382 * XXX event_limit might not quite work as expected on inherited
7386 event->pending_kill = POLL_IN;
7387 if (events && atomic_dec_and_test(&event->event_limit)) {
7389 event->pending_kill = POLL_HUP;
7391 perf_event_disable_inatomic(event);
7394 READ_ONCE(event->overflow_handler)(event, data, regs);
7396 if (*perf_event_fasync(event) && event->pending_kill) {
7397 event->pending_wakeup = 1;
7398 irq_work_queue(&event->pending);
7404 int perf_event_overflow(struct perf_event *event,
7405 struct perf_sample_data *data,
7406 struct pt_regs *regs)
7408 return __perf_event_overflow(event, 1, data, regs);
7412 * Generic software event infrastructure
7415 struct swevent_htable {
7416 struct swevent_hlist *swevent_hlist;
7417 struct mutex hlist_mutex;
7420 /* Recursion avoidance in each contexts */
7421 int recursion[PERF_NR_CONTEXTS];
7424 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7427 * We directly increment event->count and keep a second value in
7428 * event->hw.period_left to count intervals. This period event
7429 * is kept in the range [-sample_period, 0] so that we can use the
7433 u64 perf_swevent_set_period(struct perf_event *event)
7435 struct hw_perf_event *hwc = &event->hw;
7436 u64 period = hwc->last_period;
7440 hwc->last_period = hwc->sample_period;
7443 old = val = local64_read(&hwc->period_left);
7447 nr = div64_u64(period + val, period);
7448 offset = nr * period;
7450 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7456 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7457 struct perf_sample_data *data,
7458 struct pt_regs *regs)
7460 struct hw_perf_event *hwc = &event->hw;
7464 overflow = perf_swevent_set_period(event);
7466 if (hwc->interrupts == MAX_INTERRUPTS)
7469 for (; overflow; overflow--) {
7470 if (__perf_event_overflow(event, throttle,
7473 * We inhibit the overflow from happening when
7474 * hwc->interrupts == MAX_INTERRUPTS.
7482 static void perf_swevent_event(struct perf_event *event, u64 nr,
7483 struct perf_sample_data *data,
7484 struct pt_regs *regs)
7486 struct hw_perf_event *hwc = &event->hw;
7488 local64_add(nr, &event->count);
7493 if (!is_sampling_event(event))
7496 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7498 return perf_swevent_overflow(event, 1, data, regs);
7500 data->period = event->hw.last_period;
7502 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7503 return perf_swevent_overflow(event, 1, data, regs);
7505 if (local64_add_negative(nr, &hwc->period_left))
7508 perf_swevent_overflow(event, 0, data, regs);
7511 static int perf_exclude_event(struct perf_event *event,
7512 struct pt_regs *regs)
7514 if (event->hw.state & PERF_HES_STOPPED)
7518 if (event->attr.exclude_user && user_mode(regs))
7521 if (event->attr.exclude_kernel && !user_mode(regs))
7528 static int perf_swevent_match(struct perf_event *event,
7529 enum perf_type_id type,
7531 struct perf_sample_data *data,
7532 struct pt_regs *regs)
7534 if (event->attr.type != type)
7537 if (event->attr.config != event_id)
7540 if (perf_exclude_event(event, regs))
7546 static inline u64 swevent_hash(u64 type, u32 event_id)
7548 u64 val = event_id | (type << 32);
7550 return hash_64(val, SWEVENT_HLIST_BITS);
7553 static inline struct hlist_head *
7554 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7556 u64 hash = swevent_hash(type, event_id);
7558 return &hlist->heads[hash];
7561 /* For the read side: events when they trigger */
7562 static inline struct hlist_head *
7563 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7565 struct swevent_hlist *hlist;
7567 hlist = rcu_dereference(swhash->swevent_hlist);
7571 return __find_swevent_head(hlist, type, event_id);
7574 /* For the event head insertion and removal in the hlist */
7575 static inline struct hlist_head *
7576 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7578 struct swevent_hlist *hlist;
7579 u32 event_id = event->attr.config;
7580 u64 type = event->attr.type;
7583 * Event scheduling is always serialized against hlist allocation
7584 * and release. Which makes the protected version suitable here.
7585 * The context lock guarantees that.
7587 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7588 lockdep_is_held(&event->ctx->lock));
7592 return __find_swevent_head(hlist, type, event_id);
7595 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7597 struct perf_sample_data *data,
7598 struct pt_regs *regs)
7600 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7601 struct perf_event *event;
7602 struct hlist_head *head;
7605 head = find_swevent_head_rcu(swhash, type, event_id);
7609 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7610 if (perf_swevent_match(event, type, event_id, data, regs))
7611 perf_swevent_event(event, nr, data, regs);
7617 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7619 int perf_swevent_get_recursion_context(void)
7621 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7623 return get_recursion_context(swhash->recursion);
7625 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7627 void perf_swevent_put_recursion_context(int rctx)
7629 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7631 put_recursion_context(swhash->recursion, rctx);
7634 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7636 struct perf_sample_data data;
7638 if (WARN_ON_ONCE(!regs))
7641 perf_sample_data_init(&data, addr, 0);
7642 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7645 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7649 preempt_disable_notrace();
7650 rctx = perf_swevent_get_recursion_context();
7651 if (unlikely(rctx < 0))
7654 ___perf_sw_event(event_id, nr, regs, addr);
7656 perf_swevent_put_recursion_context(rctx);
7658 preempt_enable_notrace();
7661 static void perf_swevent_read(struct perf_event *event)
7665 static int perf_swevent_add(struct perf_event *event, int flags)
7667 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7668 struct hw_perf_event *hwc = &event->hw;
7669 struct hlist_head *head;
7671 if (is_sampling_event(event)) {
7672 hwc->last_period = hwc->sample_period;
7673 perf_swevent_set_period(event);
7676 hwc->state = !(flags & PERF_EF_START);
7678 head = find_swevent_head(swhash, event);
7679 if (WARN_ON_ONCE(!head))
7682 hlist_add_head_rcu(&event->hlist_entry, head);
7683 perf_event_update_userpage(event);
7688 static void perf_swevent_del(struct perf_event *event, int flags)
7690 hlist_del_rcu(&event->hlist_entry);
7693 static void perf_swevent_start(struct perf_event *event, int flags)
7695 event->hw.state = 0;
7698 static void perf_swevent_stop(struct perf_event *event, int flags)
7700 event->hw.state = PERF_HES_STOPPED;
7703 /* Deref the hlist from the update side */
7704 static inline struct swevent_hlist *
7705 swevent_hlist_deref(struct swevent_htable *swhash)
7707 return rcu_dereference_protected(swhash->swevent_hlist,
7708 lockdep_is_held(&swhash->hlist_mutex));
7711 static void swevent_hlist_release(struct swevent_htable *swhash)
7713 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7718 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7719 kfree_rcu(hlist, rcu_head);
7722 static void swevent_hlist_put_cpu(int cpu)
7724 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7726 mutex_lock(&swhash->hlist_mutex);
7728 if (!--swhash->hlist_refcount)
7729 swevent_hlist_release(swhash);
7731 mutex_unlock(&swhash->hlist_mutex);
7734 static void swevent_hlist_put(void)
7738 for_each_possible_cpu(cpu)
7739 swevent_hlist_put_cpu(cpu);
7742 static int swevent_hlist_get_cpu(int cpu)
7744 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7747 mutex_lock(&swhash->hlist_mutex);
7748 if (!swevent_hlist_deref(swhash) &&
7749 cpumask_test_cpu(cpu, perf_online_mask)) {
7750 struct swevent_hlist *hlist;
7752 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7757 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7759 swhash->hlist_refcount++;
7761 mutex_unlock(&swhash->hlist_mutex);
7766 static int swevent_hlist_get(void)
7768 int err, cpu, failed_cpu;
7770 mutex_lock(&pmus_lock);
7771 for_each_possible_cpu(cpu) {
7772 err = swevent_hlist_get_cpu(cpu);
7778 mutex_unlock(&pmus_lock);
7781 for_each_possible_cpu(cpu) {
7782 if (cpu == failed_cpu)
7784 swevent_hlist_put_cpu(cpu);
7786 mutex_unlock(&pmus_lock);
7790 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7792 static void sw_perf_event_destroy(struct perf_event *event)
7794 u64 event_id = event->attr.config;
7796 WARN_ON(event->parent);
7798 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7799 swevent_hlist_put();
7802 static int perf_swevent_init(struct perf_event *event)
7804 u64 event_id = event->attr.config;
7806 if (event->attr.type != PERF_TYPE_SOFTWARE)
7810 * no branch sampling for software events
7812 if (has_branch_stack(event))
7816 case PERF_COUNT_SW_CPU_CLOCK:
7817 case PERF_COUNT_SW_TASK_CLOCK:
7824 if (event_id >= PERF_COUNT_SW_MAX)
7827 if (!event->parent) {
7830 err = swevent_hlist_get();
7834 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7835 event->destroy = sw_perf_event_destroy;
7841 static struct pmu perf_swevent = {
7842 .task_ctx_nr = perf_sw_context,
7844 .capabilities = PERF_PMU_CAP_NO_NMI,
7846 .event_init = perf_swevent_init,
7847 .add = perf_swevent_add,
7848 .del = perf_swevent_del,
7849 .start = perf_swevent_start,
7850 .stop = perf_swevent_stop,
7851 .read = perf_swevent_read,
7854 #ifdef CONFIG_EVENT_TRACING
7856 static int perf_tp_filter_match(struct perf_event *event,
7857 struct perf_sample_data *data)
7859 void *record = data->raw->frag.data;
7861 /* only top level events have filters set */
7863 event = event->parent;
7865 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7870 static int perf_tp_event_match(struct perf_event *event,
7871 struct perf_sample_data *data,
7872 struct pt_regs *regs)
7874 if (event->hw.state & PERF_HES_STOPPED)
7877 * All tracepoints are from kernel-space.
7879 if (event->attr.exclude_kernel)
7882 if (!perf_tp_filter_match(event, data))
7888 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7889 struct trace_event_call *call, u64 count,
7890 struct pt_regs *regs, struct hlist_head *head,
7891 struct task_struct *task)
7893 if (bpf_prog_array_valid(call)) {
7894 *(struct pt_regs **)raw_data = regs;
7895 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
7896 perf_swevent_put_recursion_context(rctx);
7900 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7903 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7905 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7906 struct pt_regs *regs, struct hlist_head *head, int rctx,
7907 struct task_struct *task)
7909 struct perf_sample_data data;
7910 struct perf_event *event;
7912 struct perf_raw_record raw = {
7919 perf_sample_data_init(&data, 0, 0);
7922 perf_trace_buf_update(record, event_type);
7924 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7925 if (perf_tp_event_match(event, &data, regs))
7926 perf_swevent_event(event, count, &data, regs);
7930 * If we got specified a target task, also iterate its context and
7931 * deliver this event there too.
7933 if (task && task != current) {
7934 struct perf_event_context *ctx;
7935 struct trace_entry *entry = record;
7938 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7942 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7943 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7945 if (event->attr.config != entry->type)
7947 if (perf_tp_event_match(event, &data, regs))
7948 perf_swevent_event(event, count, &data, regs);
7954 perf_swevent_put_recursion_context(rctx);
7956 EXPORT_SYMBOL_GPL(perf_tp_event);
7958 static void tp_perf_event_destroy(struct perf_event *event)
7960 perf_trace_destroy(event);
7963 static int perf_tp_event_init(struct perf_event *event)
7967 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7971 * no branch sampling for tracepoint events
7973 if (has_branch_stack(event))
7976 err = perf_trace_init(event);
7980 event->destroy = tp_perf_event_destroy;
7985 static struct pmu perf_tracepoint = {
7986 .task_ctx_nr = perf_sw_context,
7988 .event_init = perf_tp_event_init,
7989 .add = perf_trace_add,
7990 .del = perf_trace_del,
7991 .start = perf_swevent_start,
7992 .stop = perf_swevent_stop,
7993 .read = perf_swevent_read,
7996 static inline void perf_tp_register(void)
7998 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8001 static void perf_event_free_filter(struct perf_event *event)
8003 ftrace_profile_free_filter(event);
8006 #ifdef CONFIG_BPF_SYSCALL
8007 static void bpf_overflow_handler(struct perf_event *event,
8008 struct perf_sample_data *data,
8009 struct pt_regs *regs)
8011 struct bpf_perf_event_data_kern ctx = {
8017 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8019 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8022 ret = BPF_PROG_RUN(event->prog, &ctx);
8025 __this_cpu_dec(bpf_prog_active);
8030 event->orig_overflow_handler(event, data, regs);
8033 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8035 struct bpf_prog *prog;
8037 if (event->overflow_handler_context)
8038 /* hw breakpoint or kernel counter */
8044 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8046 return PTR_ERR(prog);
8049 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8050 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8054 static void perf_event_free_bpf_handler(struct perf_event *event)
8056 struct bpf_prog *prog = event->prog;
8061 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8066 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8070 static void perf_event_free_bpf_handler(struct perf_event *event)
8075 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8077 bool is_kprobe, is_tracepoint, is_syscall_tp;
8078 struct bpf_prog *prog;
8081 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8082 return perf_event_set_bpf_handler(event, prog_fd);
8084 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8085 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8086 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8087 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8088 /* bpf programs can only be attached to u/kprobe or tracepoint */
8091 prog = bpf_prog_get(prog_fd);
8093 return PTR_ERR(prog);
8095 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8096 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8097 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8098 /* valid fd, but invalid bpf program type */
8103 if (is_tracepoint || is_syscall_tp) {
8104 int off = trace_event_get_offsets(event->tp_event);
8106 if (prog->aux->max_ctx_offset > off) {
8112 ret = perf_event_attach_bpf_prog(event, prog);
8118 static void perf_event_free_bpf_prog(struct perf_event *event)
8120 if (event->attr.type != PERF_TYPE_TRACEPOINT) {
8121 perf_event_free_bpf_handler(event);
8124 perf_event_detach_bpf_prog(event);
8129 static inline void perf_tp_register(void)
8133 static void perf_event_free_filter(struct perf_event *event)
8137 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8142 static void perf_event_free_bpf_prog(struct perf_event *event)
8145 #endif /* CONFIG_EVENT_TRACING */
8147 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8148 void perf_bp_event(struct perf_event *bp, void *data)
8150 struct perf_sample_data sample;
8151 struct pt_regs *regs = data;
8153 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8155 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8156 perf_swevent_event(bp, 1, &sample, regs);
8161 * Allocate a new address filter
8163 static struct perf_addr_filter *
8164 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8166 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8167 struct perf_addr_filter *filter;
8169 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8173 INIT_LIST_HEAD(&filter->entry);
8174 list_add_tail(&filter->entry, filters);
8179 static void free_filters_list(struct list_head *filters)
8181 struct perf_addr_filter *filter, *iter;
8183 list_for_each_entry_safe(filter, iter, filters, entry) {
8185 iput(filter->inode);
8186 list_del(&filter->entry);
8192 * Free existing address filters and optionally install new ones
8194 static void perf_addr_filters_splice(struct perf_event *event,
8195 struct list_head *head)
8197 unsigned long flags;
8200 if (!has_addr_filter(event))
8203 /* don't bother with children, they don't have their own filters */
8207 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8209 list_splice_init(&event->addr_filters.list, &list);
8211 list_splice(head, &event->addr_filters.list);
8213 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8215 free_filters_list(&list);
8219 * Scan through mm's vmas and see if one of them matches the
8220 * @filter; if so, adjust filter's address range.
8221 * Called with mm::mmap_sem down for reading.
8223 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8224 struct mm_struct *mm)
8226 struct vm_area_struct *vma;
8228 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8229 struct file *file = vma->vm_file;
8230 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8231 unsigned long vma_size = vma->vm_end - vma->vm_start;
8236 if (!perf_addr_filter_match(filter, file, off, vma_size))
8239 return vma->vm_start;
8246 * Update event's address range filters based on the
8247 * task's existing mappings, if any.
8249 static void perf_event_addr_filters_apply(struct perf_event *event)
8251 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8252 struct task_struct *task = READ_ONCE(event->ctx->task);
8253 struct perf_addr_filter *filter;
8254 struct mm_struct *mm = NULL;
8255 unsigned int count = 0;
8256 unsigned long flags;
8259 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8260 * will stop on the parent's child_mutex that our caller is also holding
8262 if (task == TASK_TOMBSTONE)
8265 if (!ifh->nr_file_filters)
8268 mm = get_task_mm(event->ctx->task);
8272 down_read(&mm->mmap_sem);
8274 raw_spin_lock_irqsave(&ifh->lock, flags);
8275 list_for_each_entry(filter, &ifh->list, entry) {
8276 event->addr_filters_offs[count] = 0;
8279 * Adjust base offset if the filter is associated to a binary
8280 * that needs to be mapped:
8283 event->addr_filters_offs[count] =
8284 perf_addr_filter_apply(filter, mm);
8289 event->addr_filters_gen++;
8290 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8292 up_read(&mm->mmap_sem);
8297 perf_event_stop(event, 1);
8301 * Address range filtering: limiting the data to certain
8302 * instruction address ranges. Filters are ioctl()ed to us from
8303 * userspace as ascii strings.
8305 * Filter string format:
8308 * where ACTION is one of the
8309 * * "filter": limit the trace to this region
8310 * * "start": start tracing from this address
8311 * * "stop": stop tracing at this address/region;
8313 * * for kernel addresses: <start address>[/<size>]
8314 * * for object files: <start address>[/<size>]@</path/to/object/file>
8316 * if <size> is not specified, the range is treated as a single address.
8330 IF_STATE_ACTION = 0,
8335 static const match_table_t if_tokens = {
8336 { IF_ACT_FILTER, "filter" },
8337 { IF_ACT_START, "start" },
8338 { IF_ACT_STOP, "stop" },
8339 { IF_SRC_FILE, "%u/%u@%s" },
8340 { IF_SRC_KERNEL, "%u/%u" },
8341 { IF_SRC_FILEADDR, "%u@%s" },
8342 { IF_SRC_KERNELADDR, "%u" },
8343 { IF_ACT_NONE, NULL },
8347 * Address filter string parser
8350 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8351 struct list_head *filters)
8353 struct perf_addr_filter *filter = NULL;
8354 char *start, *orig, *filename = NULL;
8356 substring_t args[MAX_OPT_ARGS];
8357 int state = IF_STATE_ACTION, token;
8358 unsigned int kernel = 0;
8361 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8365 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8371 /* filter definition begins */
8372 if (state == IF_STATE_ACTION) {
8373 filter = perf_addr_filter_new(event, filters);
8378 token = match_token(start, if_tokens, args);
8385 if (state != IF_STATE_ACTION)
8388 state = IF_STATE_SOURCE;
8391 case IF_SRC_KERNELADDR:
8395 case IF_SRC_FILEADDR:
8397 if (state != IF_STATE_SOURCE)
8400 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8404 ret = kstrtoul(args[0].from, 0, &filter->offset);
8408 if (filter->range) {
8410 ret = kstrtoul(args[1].from, 0, &filter->size);
8415 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8416 int fpos = filter->range ? 2 : 1;
8418 filename = match_strdup(&args[fpos]);
8425 state = IF_STATE_END;
8433 * Filter definition is fully parsed, validate and install it.
8434 * Make sure that it doesn't contradict itself or the event's
8437 if (state == IF_STATE_END) {
8439 if (kernel && event->attr.exclude_kernel)
8447 * For now, we only support file-based filters
8448 * in per-task events; doing so for CPU-wide
8449 * events requires additional context switching
8450 * trickery, since same object code will be
8451 * mapped at different virtual addresses in
8452 * different processes.
8455 if (!event->ctx->task)
8456 goto fail_free_name;
8458 /* look up the path and grab its inode */
8459 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8461 goto fail_free_name;
8463 filter->inode = igrab(d_inode(path.dentry));
8469 if (!filter->inode ||
8470 !S_ISREG(filter->inode->i_mode))
8471 /* free_filters_list() will iput() */
8474 event->addr_filters.nr_file_filters++;
8477 /* ready to consume more filters */
8478 state = IF_STATE_ACTION;
8483 if (state != IF_STATE_ACTION)
8493 free_filters_list(filters);
8500 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8506 * Since this is called in perf_ioctl() path, we're already holding
8509 lockdep_assert_held(&event->ctx->mutex);
8511 if (WARN_ON_ONCE(event->parent))
8514 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8516 goto fail_clear_files;
8518 ret = event->pmu->addr_filters_validate(&filters);
8520 goto fail_free_filters;
8522 /* remove existing filters, if any */
8523 perf_addr_filters_splice(event, &filters);
8525 /* install new filters */
8526 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8531 free_filters_list(&filters);
8534 event->addr_filters.nr_file_filters = 0;
8540 perf_tracepoint_set_filter(struct perf_event *event, char *filter_str)
8542 struct perf_event_context *ctx = event->ctx;
8546 * Beware, here be dragons!!
8548 * the tracepoint muck will deadlock against ctx->mutex, but the tracepoint
8549 * stuff does not actually need it. So temporarily drop ctx->mutex. As per
8550 * perf_event_ctx_lock() we already have a reference on ctx.
8552 * This can result in event getting moved to a different ctx, but that
8553 * does not affect the tracepoint state.
8555 mutex_unlock(&ctx->mutex);
8556 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
8557 mutex_lock(&ctx->mutex);
8562 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8567 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8568 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8569 !has_addr_filter(event))
8572 filter_str = strndup_user(arg, PAGE_SIZE);
8573 if (IS_ERR(filter_str))
8574 return PTR_ERR(filter_str);
8576 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8577 event->attr.type == PERF_TYPE_TRACEPOINT)
8578 ret = perf_tracepoint_set_filter(event, filter_str);
8579 else if (has_addr_filter(event))
8580 ret = perf_event_set_addr_filter(event, filter_str);
8587 * hrtimer based swevent callback
8590 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8592 enum hrtimer_restart ret = HRTIMER_RESTART;
8593 struct perf_sample_data data;
8594 struct pt_regs *regs;
8595 struct perf_event *event;
8598 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8600 if (event->state != PERF_EVENT_STATE_ACTIVE)
8601 return HRTIMER_NORESTART;
8603 event->pmu->read(event);
8605 perf_sample_data_init(&data, 0, event->hw.last_period);
8606 regs = get_irq_regs();
8608 if (regs && !perf_exclude_event(event, regs)) {
8609 if (!(event->attr.exclude_idle && is_idle_task(current)))
8610 if (__perf_event_overflow(event, 1, &data, regs))
8611 ret = HRTIMER_NORESTART;
8614 period = max_t(u64, 10000, event->hw.sample_period);
8615 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8620 static void perf_swevent_start_hrtimer(struct perf_event *event)
8622 struct hw_perf_event *hwc = &event->hw;
8625 if (!is_sampling_event(event))
8628 period = local64_read(&hwc->period_left);
8633 local64_set(&hwc->period_left, 0);
8635 period = max_t(u64, 10000, hwc->sample_period);
8637 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8638 HRTIMER_MODE_REL_PINNED);
8641 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8643 struct hw_perf_event *hwc = &event->hw;
8645 if (is_sampling_event(event)) {
8646 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8647 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8649 hrtimer_cancel(&hwc->hrtimer);
8653 static void perf_swevent_init_hrtimer(struct perf_event *event)
8655 struct hw_perf_event *hwc = &event->hw;
8657 if (!is_sampling_event(event))
8660 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8661 hwc->hrtimer.function = perf_swevent_hrtimer;
8664 * Since hrtimers have a fixed rate, we can do a static freq->period
8665 * mapping and avoid the whole period adjust feedback stuff.
8667 if (event->attr.freq) {
8668 long freq = event->attr.sample_freq;
8670 event->attr.sample_period = NSEC_PER_SEC / freq;
8671 hwc->sample_period = event->attr.sample_period;
8672 local64_set(&hwc->period_left, hwc->sample_period);
8673 hwc->last_period = hwc->sample_period;
8674 event->attr.freq = 0;
8679 * Software event: cpu wall time clock
8682 static void cpu_clock_event_update(struct perf_event *event)
8687 now = local_clock();
8688 prev = local64_xchg(&event->hw.prev_count, now);
8689 local64_add(now - prev, &event->count);
8692 static void cpu_clock_event_start(struct perf_event *event, int flags)
8694 local64_set(&event->hw.prev_count, local_clock());
8695 perf_swevent_start_hrtimer(event);
8698 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8700 perf_swevent_cancel_hrtimer(event);
8701 cpu_clock_event_update(event);
8704 static int cpu_clock_event_add(struct perf_event *event, int flags)
8706 if (flags & PERF_EF_START)
8707 cpu_clock_event_start(event, flags);
8708 perf_event_update_userpage(event);
8713 static void cpu_clock_event_del(struct perf_event *event, int flags)
8715 cpu_clock_event_stop(event, flags);
8718 static void cpu_clock_event_read(struct perf_event *event)
8720 cpu_clock_event_update(event);
8723 static int cpu_clock_event_init(struct perf_event *event)
8725 if (event->attr.type != PERF_TYPE_SOFTWARE)
8728 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8732 * no branch sampling for software events
8734 if (has_branch_stack(event))
8737 perf_swevent_init_hrtimer(event);
8742 static struct pmu perf_cpu_clock = {
8743 .task_ctx_nr = perf_sw_context,
8745 .capabilities = PERF_PMU_CAP_NO_NMI,
8747 .event_init = cpu_clock_event_init,
8748 .add = cpu_clock_event_add,
8749 .del = cpu_clock_event_del,
8750 .start = cpu_clock_event_start,
8751 .stop = cpu_clock_event_stop,
8752 .read = cpu_clock_event_read,
8756 * Software event: task time clock
8759 static void task_clock_event_update(struct perf_event *event, u64 now)
8764 prev = local64_xchg(&event->hw.prev_count, now);
8766 local64_add(delta, &event->count);
8769 static void task_clock_event_start(struct perf_event *event, int flags)
8771 local64_set(&event->hw.prev_count, event->ctx->time);
8772 perf_swevent_start_hrtimer(event);
8775 static void task_clock_event_stop(struct perf_event *event, int flags)
8777 perf_swevent_cancel_hrtimer(event);
8778 task_clock_event_update(event, event->ctx->time);
8781 static int task_clock_event_add(struct perf_event *event, int flags)
8783 if (flags & PERF_EF_START)
8784 task_clock_event_start(event, flags);
8785 perf_event_update_userpage(event);
8790 static void task_clock_event_del(struct perf_event *event, int flags)
8792 task_clock_event_stop(event, PERF_EF_UPDATE);
8795 static void task_clock_event_read(struct perf_event *event)
8797 u64 now = perf_clock();
8798 u64 delta = now - event->ctx->timestamp;
8799 u64 time = event->ctx->time + delta;
8801 task_clock_event_update(event, time);
8804 static int task_clock_event_init(struct perf_event *event)
8806 if (event->attr.type != PERF_TYPE_SOFTWARE)
8809 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8813 * no branch sampling for software events
8815 if (has_branch_stack(event))
8818 perf_swevent_init_hrtimer(event);
8823 static struct pmu perf_task_clock = {
8824 .task_ctx_nr = perf_sw_context,
8826 .capabilities = PERF_PMU_CAP_NO_NMI,
8828 .event_init = task_clock_event_init,
8829 .add = task_clock_event_add,
8830 .del = task_clock_event_del,
8831 .start = task_clock_event_start,
8832 .stop = task_clock_event_stop,
8833 .read = task_clock_event_read,
8836 static void perf_pmu_nop_void(struct pmu *pmu)
8840 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8844 static int perf_pmu_nop_int(struct pmu *pmu)
8849 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8851 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8853 __this_cpu_write(nop_txn_flags, flags);
8855 if (flags & ~PERF_PMU_TXN_ADD)
8858 perf_pmu_disable(pmu);
8861 static int perf_pmu_commit_txn(struct pmu *pmu)
8863 unsigned int flags = __this_cpu_read(nop_txn_flags);
8865 __this_cpu_write(nop_txn_flags, 0);
8867 if (flags & ~PERF_PMU_TXN_ADD)
8870 perf_pmu_enable(pmu);
8874 static void perf_pmu_cancel_txn(struct pmu *pmu)
8876 unsigned int flags = __this_cpu_read(nop_txn_flags);
8878 __this_cpu_write(nop_txn_flags, 0);
8880 if (flags & ~PERF_PMU_TXN_ADD)
8883 perf_pmu_enable(pmu);
8886 static int perf_event_idx_default(struct perf_event *event)
8892 * Ensures all contexts with the same task_ctx_nr have the same
8893 * pmu_cpu_context too.
8895 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8902 list_for_each_entry(pmu, &pmus, entry) {
8903 if (pmu->task_ctx_nr == ctxn)
8904 return pmu->pmu_cpu_context;
8910 static void free_pmu_context(struct pmu *pmu)
8913 * Static contexts such as perf_sw_context have a global lifetime
8914 * and may be shared between different PMUs. Avoid freeing them
8915 * when a single PMU is going away.
8917 if (pmu->task_ctx_nr > perf_invalid_context)
8920 mutex_lock(&pmus_lock);
8921 free_percpu(pmu->pmu_cpu_context);
8922 mutex_unlock(&pmus_lock);
8926 * Let userspace know that this PMU supports address range filtering:
8928 static ssize_t nr_addr_filters_show(struct device *dev,
8929 struct device_attribute *attr,
8932 struct pmu *pmu = dev_get_drvdata(dev);
8934 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8936 DEVICE_ATTR_RO(nr_addr_filters);
8938 static struct idr pmu_idr;
8941 type_show(struct device *dev, struct device_attribute *attr, char *page)
8943 struct pmu *pmu = dev_get_drvdata(dev);
8945 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8947 static DEVICE_ATTR_RO(type);
8950 perf_event_mux_interval_ms_show(struct device *dev,
8951 struct device_attribute *attr,
8954 struct pmu *pmu = dev_get_drvdata(dev);
8956 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8959 static DEFINE_MUTEX(mux_interval_mutex);
8962 perf_event_mux_interval_ms_store(struct device *dev,
8963 struct device_attribute *attr,
8964 const char *buf, size_t count)
8966 struct pmu *pmu = dev_get_drvdata(dev);
8967 int timer, cpu, ret;
8969 ret = kstrtoint(buf, 0, &timer);
8976 /* same value, noting to do */
8977 if (timer == pmu->hrtimer_interval_ms)
8980 mutex_lock(&mux_interval_mutex);
8981 pmu->hrtimer_interval_ms = timer;
8983 /* update all cpuctx for this PMU */
8985 for_each_online_cpu(cpu) {
8986 struct perf_cpu_context *cpuctx;
8987 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8988 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8990 cpu_function_call(cpu,
8991 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8994 mutex_unlock(&mux_interval_mutex);
8998 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9000 static struct attribute *pmu_dev_attrs[] = {
9001 &dev_attr_type.attr,
9002 &dev_attr_perf_event_mux_interval_ms.attr,
9005 ATTRIBUTE_GROUPS(pmu_dev);
9007 static int pmu_bus_running;
9008 static struct bus_type pmu_bus = {
9009 .name = "event_source",
9010 .dev_groups = pmu_dev_groups,
9013 static void pmu_dev_release(struct device *dev)
9018 static int pmu_dev_alloc(struct pmu *pmu)
9022 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9026 pmu->dev->groups = pmu->attr_groups;
9027 device_initialize(pmu->dev);
9028 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9032 dev_set_drvdata(pmu->dev, pmu);
9033 pmu->dev->bus = &pmu_bus;
9034 pmu->dev->release = pmu_dev_release;
9035 ret = device_add(pmu->dev);
9039 /* For PMUs with address filters, throw in an extra attribute: */
9040 if (pmu->nr_addr_filters)
9041 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9050 device_del(pmu->dev);
9053 put_device(pmu->dev);
9057 static struct lock_class_key cpuctx_mutex;
9058 static struct lock_class_key cpuctx_lock;
9060 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9064 mutex_lock(&pmus_lock);
9066 pmu->pmu_disable_count = alloc_percpu(int);
9067 if (!pmu->pmu_disable_count)
9076 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9084 if (pmu_bus_running) {
9085 ret = pmu_dev_alloc(pmu);
9091 if (pmu->task_ctx_nr == perf_hw_context) {
9092 static int hw_context_taken = 0;
9095 * Other than systems with heterogeneous CPUs, it never makes
9096 * sense for two PMUs to share perf_hw_context. PMUs which are
9097 * uncore must use perf_invalid_context.
9099 if (WARN_ON_ONCE(hw_context_taken &&
9100 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9101 pmu->task_ctx_nr = perf_invalid_context;
9103 hw_context_taken = 1;
9106 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9107 if (pmu->pmu_cpu_context)
9108 goto got_cpu_context;
9111 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9112 if (!pmu->pmu_cpu_context)
9115 for_each_possible_cpu(cpu) {
9116 struct perf_cpu_context *cpuctx;
9118 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9119 __perf_event_init_context(&cpuctx->ctx);
9120 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9121 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9122 cpuctx->ctx.pmu = pmu;
9123 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9125 __perf_mux_hrtimer_init(cpuctx, cpu);
9129 if (!pmu->start_txn) {
9130 if (pmu->pmu_enable) {
9132 * If we have pmu_enable/pmu_disable calls, install
9133 * transaction stubs that use that to try and batch
9134 * hardware accesses.
9136 pmu->start_txn = perf_pmu_start_txn;
9137 pmu->commit_txn = perf_pmu_commit_txn;
9138 pmu->cancel_txn = perf_pmu_cancel_txn;
9140 pmu->start_txn = perf_pmu_nop_txn;
9141 pmu->commit_txn = perf_pmu_nop_int;
9142 pmu->cancel_txn = perf_pmu_nop_void;
9146 if (!pmu->pmu_enable) {
9147 pmu->pmu_enable = perf_pmu_nop_void;
9148 pmu->pmu_disable = perf_pmu_nop_void;
9151 if (!pmu->event_idx)
9152 pmu->event_idx = perf_event_idx_default;
9154 list_add_rcu(&pmu->entry, &pmus);
9155 atomic_set(&pmu->exclusive_cnt, 0);
9158 mutex_unlock(&pmus_lock);
9163 device_del(pmu->dev);
9164 put_device(pmu->dev);
9167 if (pmu->type >= PERF_TYPE_MAX)
9168 idr_remove(&pmu_idr, pmu->type);
9171 free_percpu(pmu->pmu_disable_count);
9174 EXPORT_SYMBOL_GPL(perf_pmu_register);
9176 void perf_pmu_unregister(struct pmu *pmu)
9180 mutex_lock(&pmus_lock);
9181 remove_device = pmu_bus_running;
9182 list_del_rcu(&pmu->entry);
9183 mutex_unlock(&pmus_lock);
9186 * We dereference the pmu list under both SRCU and regular RCU, so
9187 * synchronize against both of those.
9189 synchronize_srcu(&pmus_srcu);
9192 free_percpu(pmu->pmu_disable_count);
9193 if (pmu->type >= PERF_TYPE_MAX)
9194 idr_remove(&pmu_idr, pmu->type);
9195 if (remove_device) {
9196 if (pmu->nr_addr_filters)
9197 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9198 device_del(pmu->dev);
9199 put_device(pmu->dev);
9201 free_pmu_context(pmu);
9203 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9205 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9207 struct perf_event_context *ctx = NULL;
9210 if (!try_module_get(pmu->module))
9214 * A number of pmu->event_init() methods iterate the sibling_list to,
9215 * for example, validate if the group fits on the PMU. Therefore,
9216 * if this is a sibling event, acquire the ctx->mutex to protect
9219 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9221 * This ctx->mutex can nest when we're called through
9222 * inheritance. See the perf_event_ctx_lock_nested() comment.
9224 ctx = perf_event_ctx_lock_nested(event->group_leader,
9225 SINGLE_DEPTH_NESTING);
9230 ret = pmu->event_init(event);
9233 perf_event_ctx_unlock(event->group_leader, ctx);
9236 module_put(pmu->module);
9241 static struct pmu *perf_init_event(struct perf_event *event)
9247 idx = srcu_read_lock(&pmus_srcu);
9249 /* Try parent's PMU first: */
9250 if (event->parent && event->parent->pmu) {
9251 pmu = event->parent->pmu;
9252 ret = perf_try_init_event(pmu, event);
9258 pmu = idr_find(&pmu_idr, event->attr.type);
9261 ret = perf_try_init_event(pmu, event);
9267 list_for_each_entry_rcu(pmu, &pmus, entry) {
9268 ret = perf_try_init_event(pmu, event);
9272 if (ret != -ENOENT) {
9277 pmu = ERR_PTR(-ENOENT);
9279 srcu_read_unlock(&pmus_srcu, idx);
9284 static void attach_sb_event(struct perf_event *event)
9286 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9288 raw_spin_lock(&pel->lock);
9289 list_add_rcu(&event->sb_list, &pel->list);
9290 raw_spin_unlock(&pel->lock);
9294 * We keep a list of all !task (and therefore per-cpu) events
9295 * that need to receive side-band records.
9297 * This avoids having to scan all the various PMU per-cpu contexts
9300 static void account_pmu_sb_event(struct perf_event *event)
9302 if (is_sb_event(event))
9303 attach_sb_event(event);
9306 static void account_event_cpu(struct perf_event *event, int cpu)
9311 if (is_cgroup_event(event))
9312 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9315 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9316 static void account_freq_event_nohz(void)
9318 #ifdef CONFIG_NO_HZ_FULL
9319 /* Lock so we don't race with concurrent unaccount */
9320 spin_lock(&nr_freq_lock);
9321 if (atomic_inc_return(&nr_freq_events) == 1)
9322 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9323 spin_unlock(&nr_freq_lock);
9327 static void account_freq_event(void)
9329 if (tick_nohz_full_enabled())
9330 account_freq_event_nohz();
9332 atomic_inc(&nr_freq_events);
9336 static void account_event(struct perf_event *event)
9343 if (event->attach_state & PERF_ATTACH_TASK)
9345 if (event->attr.mmap || event->attr.mmap_data)
9346 atomic_inc(&nr_mmap_events);
9347 if (event->attr.comm)
9348 atomic_inc(&nr_comm_events);
9349 if (event->attr.namespaces)
9350 atomic_inc(&nr_namespaces_events);
9351 if (event->attr.task)
9352 atomic_inc(&nr_task_events);
9353 if (event->attr.freq)
9354 account_freq_event();
9355 if (event->attr.context_switch) {
9356 atomic_inc(&nr_switch_events);
9359 if (has_branch_stack(event))
9361 if (is_cgroup_event(event))
9366 * We need the mutex here because static_branch_enable()
9367 * must complete *before* the perf_sched_count increment
9370 if (atomic_inc_not_zero(&perf_sched_count))
9373 mutex_lock(&perf_sched_mutex);
9374 if (!atomic_read(&perf_sched_count)) {
9375 static_branch_enable(&perf_sched_events);
9377 * Guarantee that all CPUs observe they key change and
9378 * call the perf scheduling hooks before proceeding to
9379 * install events that need them.
9381 synchronize_sched();
9384 * Now that we have waited for the sync_sched(), allow further
9385 * increments to by-pass the mutex.
9387 atomic_inc(&perf_sched_count);
9388 mutex_unlock(&perf_sched_mutex);
9392 account_event_cpu(event, event->cpu);
9394 account_pmu_sb_event(event);
9398 * Allocate and initialize a event structure
9400 static struct perf_event *
9401 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9402 struct task_struct *task,
9403 struct perf_event *group_leader,
9404 struct perf_event *parent_event,
9405 perf_overflow_handler_t overflow_handler,
9406 void *context, int cgroup_fd)
9409 struct perf_event *event;
9410 struct hw_perf_event *hwc;
9413 if ((unsigned)cpu >= nr_cpu_ids) {
9414 if (!task || cpu != -1)
9415 return ERR_PTR(-EINVAL);
9418 event = kzalloc(sizeof(*event), GFP_KERNEL);
9420 return ERR_PTR(-ENOMEM);
9423 * Single events are their own group leaders, with an
9424 * empty sibling list:
9427 group_leader = event;
9429 mutex_init(&event->child_mutex);
9430 INIT_LIST_HEAD(&event->child_list);
9432 INIT_LIST_HEAD(&event->group_entry);
9433 INIT_LIST_HEAD(&event->event_entry);
9434 INIT_LIST_HEAD(&event->sibling_list);
9435 INIT_LIST_HEAD(&event->rb_entry);
9436 INIT_LIST_HEAD(&event->active_entry);
9437 INIT_LIST_HEAD(&event->addr_filters.list);
9438 INIT_HLIST_NODE(&event->hlist_entry);
9441 init_waitqueue_head(&event->waitq);
9442 init_irq_work(&event->pending, perf_pending_event);
9444 mutex_init(&event->mmap_mutex);
9445 raw_spin_lock_init(&event->addr_filters.lock);
9447 atomic_long_set(&event->refcount, 1);
9449 event->attr = *attr;
9450 event->group_leader = group_leader;
9454 event->parent = parent_event;
9456 event->ns = get_pid_ns(task_active_pid_ns(current));
9457 event->id = atomic64_inc_return(&perf_event_id);
9459 event->state = PERF_EVENT_STATE_INACTIVE;
9462 event->attach_state = PERF_ATTACH_TASK;
9464 * XXX pmu::event_init needs to know what task to account to
9465 * and we cannot use the ctx information because we need the
9466 * pmu before we get a ctx.
9468 event->hw.target = task;
9471 event->clock = &local_clock;
9473 event->clock = parent_event->clock;
9475 if (!overflow_handler && parent_event) {
9476 overflow_handler = parent_event->overflow_handler;
9477 context = parent_event->overflow_handler_context;
9478 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9479 if (overflow_handler == bpf_overflow_handler) {
9480 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9483 err = PTR_ERR(prog);
9487 event->orig_overflow_handler =
9488 parent_event->orig_overflow_handler;
9493 if (overflow_handler) {
9494 event->overflow_handler = overflow_handler;
9495 event->overflow_handler_context = context;
9496 } else if (is_write_backward(event)){
9497 event->overflow_handler = perf_event_output_backward;
9498 event->overflow_handler_context = NULL;
9500 event->overflow_handler = perf_event_output_forward;
9501 event->overflow_handler_context = NULL;
9504 perf_event__state_init(event);
9509 hwc->sample_period = attr->sample_period;
9510 if (attr->freq && attr->sample_freq)
9511 hwc->sample_period = 1;
9512 hwc->last_period = hwc->sample_period;
9514 local64_set(&hwc->period_left, hwc->sample_period);
9517 * We currently do not support PERF_SAMPLE_READ on inherited events.
9518 * See perf_output_read().
9520 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9523 if (!has_branch_stack(event))
9524 event->attr.branch_sample_type = 0;
9526 if (cgroup_fd != -1) {
9527 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9532 pmu = perf_init_event(event);
9538 err = exclusive_event_init(event);
9542 if (has_addr_filter(event)) {
9543 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9544 sizeof(unsigned long),
9546 if (!event->addr_filters_offs) {
9551 /* force hw sync on the address filters */
9552 event->addr_filters_gen = 1;
9555 if (!event->parent) {
9556 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9557 err = get_callchain_buffers(attr->sample_max_stack);
9559 goto err_addr_filters;
9563 /* symmetric to unaccount_event() in _free_event() */
9564 account_event(event);
9569 kfree(event->addr_filters_offs);
9572 exclusive_event_destroy(event);
9576 event->destroy(event);
9577 module_put(pmu->module);
9579 if (is_cgroup_event(event))
9580 perf_detach_cgroup(event);
9582 put_pid_ns(event->ns);
9585 return ERR_PTR(err);
9588 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9589 struct perf_event_attr *attr)
9594 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9598 * zero the full structure, so that a short copy will be nice.
9600 memset(attr, 0, sizeof(*attr));
9602 ret = get_user(size, &uattr->size);
9606 if (size > PAGE_SIZE) /* silly large */
9609 if (!size) /* abi compat */
9610 size = PERF_ATTR_SIZE_VER0;
9612 if (size < PERF_ATTR_SIZE_VER0)
9616 * If we're handed a bigger struct than we know of,
9617 * ensure all the unknown bits are 0 - i.e. new
9618 * user-space does not rely on any kernel feature
9619 * extensions we dont know about yet.
9621 if (size > sizeof(*attr)) {
9622 unsigned char __user *addr;
9623 unsigned char __user *end;
9626 addr = (void __user *)uattr + sizeof(*attr);
9627 end = (void __user *)uattr + size;
9629 for (; addr < end; addr++) {
9630 ret = get_user(val, addr);
9636 size = sizeof(*attr);
9639 ret = copy_from_user(attr, uattr, size);
9645 if (attr->__reserved_1)
9648 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9651 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9654 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9655 u64 mask = attr->branch_sample_type;
9657 /* only using defined bits */
9658 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9661 /* at least one branch bit must be set */
9662 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9665 /* propagate priv level, when not set for branch */
9666 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9668 /* exclude_kernel checked on syscall entry */
9669 if (!attr->exclude_kernel)
9670 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9672 if (!attr->exclude_user)
9673 mask |= PERF_SAMPLE_BRANCH_USER;
9675 if (!attr->exclude_hv)
9676 mask |= PERF_SAMPLE_BRANCH_HV;
9678 * adjust user setting (for HW filter setup)
9680 attr->branch_sample_type = mask;
9682 /* privileged levels capture (kernel, hv): check permissions */
9683 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9684 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9688 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9689 ret = perf_reg_validate(attr->sample_regs_user);
9694 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9695 if (!arch_perf_have_user_stack_dump())
9699 * We have __u32 type for the size, but so far
9700 * we can only use __u16 as maximum due to the
9701 * __u16 sample size limit.
9703 if (attr->sample_stack_user >= USHRT_MAX)
9705 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9709 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9710 ret = perf_reg_validate(attr->sample_regs_intr);
9715 put_user(sizeof(*attr), &uattr->size);
9721 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9723 struct ring_buffer *rb = NULL;
9729 /* don't allow circular references */
9730 if (event == output_event)
9734 * Don't allow cross-cpu buffers
9736 if (output_event->cpu != event->cpu)
9740 * If its not a per-cpu rb, it must be the same task.
9742 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9746 * Mixing clocks in the same buffer is trouble you don't need.
9748 if (output_event->clock != event->clock)
9752 * Either writing ring buffer from beginning or from end.
9753 * Mixing is not allowed.
9755 if (is_write_backward(output_event) != is_write_backward(event))
9759 * If both events generate aux data, they must be on the same PMU
9761 if (has_aux(event) && has_aux(output_event) &&
9762 event->pmu != output_event->pmu)
9766 mutex_lock(&event->mmap_mutex);
9767 /* Can't redirect output if we've got an active mmap() */
9768 if (atomic_read(&event->mmap_count))
9772 /* get the rb we want to redirect to */
9773 rb = ring_buffer_get(output_event);
9778 ring_buffer_attach(event, rb);
9782 mutex_unlock(&event->mmap_mutex);
9788 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9794 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9797 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9799 bool nmi_safe = false;
9802 case CLOCK_MONOTONIC:
9803 event->clock = &ktime_get_mono_fast_ns;
9807 case CLOCK_MONOTONIC_RAW:
9808 event->clock = &ktime_get_raw_fast_ns;
9812 case CLOCK_REALTIME:
9813 event->clock = &ktime_get_real_ns;
9816 case CLOCK_BOOTTIME:
9817 event->clock = &ktime_get_boot_ns;
9821 event->clock = &ktime_get_tai_ns;
9828 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9835 * Variation on perf_event_ctx_lock_nested(), except we take two context
9838 static struct perf_event_context *
9839 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9840 struct perf_event_context *ctx)
9842 struct perf_event_context *gctx;
9846 gctx = READ_ONCE(group_leader->ctx);
9847 if (!atomic_inc_not_zero(&gctx->refcount)) {
9853 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9855 if (group_leader->ctx != gctx) {
9856 mutex_unlock(&ctx->mutex);
9857 mutex_unlock(&gctx->mutex);
9866 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9868 * @attr_uptr: event_id type attributes for monitoring/sampling
9871 * @group_fd: group leader event fd
9873 SYSCALL_DEFINE5(perf_event_open,
9874 struct perf_event_attr __user *, attr_uptr,
9875 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9877 struct perf_event *group_leader = NULL, *output_event = NULL;
9878 struct perf_event *event, *sibling;
9879 struct perf_event_attr attr;
9880 struct perf_event_context *ctx, *uninitialized_var(gctx);
9881 struct file *event_file = NULL;
9882 struct fd group = {NULL, 0};
9883 struct task_struct *task = NULL;
9888 int f_flags = O_RDWR;
9891 /* for future expandability... */
9892 if (flags & ~PERF_FLAG_ALL)
9895 err = perf_copy_attr(attr_uptr, &attr);
9899 if (!attr.exclude_kernel) {
9900 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9904 if (attr.namespaces) {
9905 if (!capable(CAP_SYS_ADMIN))
9910 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9913 if (attr.sample_period & (1ULL << 63))
9917 /* Only privileged users can get physical addresses */
9918 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
9919 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9922 if (!attr.sample_max_stack)
9923 attr.sample_max_stack = sysctl_perf_event_max_stack;
9926 * In cgroup mode, the pid argument is used to pass the fd
9927 * opened to the cgroup directory in cgroupfs. The cpu argument
9928 * designates the cpu on which to monitor threads from that
9931 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9934 if (flags & PERF_FLAG_FD_CLOEXEC)
9935 f_flags |= O_CLOEXEC;
9937 event_fd = get_unused_fd_flags(f_flags);
9941 if (group_fd != -1) {
9942 err = perf_fget_light(group_fd, &group);
9945 group_leader = group.file->private_data;
9946 if (flags & PERF_FLAG_FD_OUTPUT)
9947 output_event = group_leader;
9948 if (flags & PERF_FLAG_FD_NO_GROUP)
9949 group_leader = NULL;
9952 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9953 task = find_lively_task_by_vpid(pid);
9955 err = PTR_ERR(task);
9960 if (task && group_leader &&
9961 group_leader->attr.inherit != attr.inherit) {
9967 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9972 * Reuse ptrace permission checks for now.
9974 * We must hold cred_guard_mutex across this and any potential
9975 * perf_install_in_context() call for this new event to
9976 * serialize against exec() altering our credentials (and the
9977 * perf_event_exit_task() that could imply).
9980 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9984 if (flags & PERF_FLAG_PID_CGROUP)
9987 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9988 NULL, NULL, cgroup_fd);
9989 if (IS_ERR(event)) {
9990 err = PTR_ERR(event);
9994 if (is_sampling_event(event)) {
9995 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10002 * Special case software events and allow them to be part of
10003 * any hardware group.
10007 if (attr.use_clockid) {
10008 err = perf_event_set_clock(event, attr.clockid);
10013 if (pmu->task_ctx_nr == perf_sw_context)
10014 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10016 if (group_leader &&
10017 (is_software_event(event) != is_software_event(group_leader))) {
10018 if (is_software_event(event)) {
10020 * If event and group_leader are not both a software
10021 * event, and event is, then group leader is not.
10023 * Allow the addition of software events to !software
10024 * groups, this is safe because software events never
10025 * fail to schedule.
10027 pmu = group_leader->pmu;
10028 } else if (is_software_event(group_leader) &&
10029 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10031 * In case the group is a pure software group, and we
10032 * try to add a hardware event, move the whole group to
10033 * the hardware context.
10040 * Get the target context (task or percpu):
10042 ctx = find_get_context(pmu, task, event);
10044 err = PTR_ERR(ctx);
10048 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10054 * Look up the group leader (we will attach this event to it):
10056 if (group_leader) {
10060 * Do not allow a recursive hierarchy (this new sibling
10061 * becoming part of another group-sibling):
10063 if (group_leader->group_leader != group_leader)
10066 /* All events in a group should have the same clock */
10067 if (group_leader->clock != event->clock)
10071 * Make sure we're both events for the same CPU;
10072 * grouping events for different CPUs is broken; since
10073 * you can never concurrently schedule them anyhow.
10075 if (group_leader->cpu != event->cpu)
10079 * Make sure we're both on the same task, or both
10082 if (group_leader->ctx->task != ctx->task)
10086 * Do not allow to attach to a group in a different task
10087 * or CPU context. If we're moving SW events, we'll fix
10088 * this up later, so allow that.
10090 if (!move_group && group_leader->ctx != ctx)
10094 * Only a group leader can be exclusive or pinned
10096 if (attr.exclusive || attr.pinned)
10100 if (output_event) {
10101 err = perf_event_set_output(event, output_event);
10106 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10108 if (IS_ERR(event_file)) {
10109 err = PTR_ERR(event_file);
10115 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10117 if (gctx->task == TASK_TOMBSTONE) {
10123 * Check if we raced against another sys_perf_event_open() call
10124 * moving the software group underneath us.
10126 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10128 * If someone moved the group out from under us, check
10129 * if this new event wound up on the same ctx, if so
10130 * its the regular !move_group case, otherwise fail.
10136 perf_event_ctx_unlock(group_leader, gctx);
10141 mutex_lock(&ctx->mutex);
10144 if (ctx->task == TASK_TOMBSTONE) {
10149 if (!perf_event_validate_size(event)) {
10156 * Check if the @cpu we're creating an event for is online.
10158 * We use the perf_cpu_context::ctx::mutex to serialize against
10159 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10161 struct perf_cpu_context *cpuctx =
10162 container_of(ctx, struct perf_cpu_context, ctx);
10164 if (!cpuctx->online) {
10172 * Must be under the same ctx::mutex as perf_install_in_context(),
10173 * because we need to serialize with concurrent event creation.
10175 if (!exclusive_event_installable(event, ctx)) {
10176 /* exclusive and group stuff are assumed mutually exclusive */
10177 WARN_ON_ONCE(move_group);
10183 WARN_ON_ONCE(ctx->parent_ctx);
10186 * This is the point on no return; we cannot fail hereafter. This is
10187 * where we start modifying current state.
10192 * See perf_event_ctx_lock() for comments on the details
10193 * of swizzling perf_event::ctx.
10195 perf_remove_from_context(group_leader, 0);
10198 list_for_each_entry(sibling, &group_leader->sibling_list,
10200 perf_remove_from_context(sibling, 0);
10205 * Wait for everybody to stop referencing the events through
10206 * the old lists, before installing it on new lists.
10211 * Install the group siblings before the group leader.
10213 * Because a group leader will try and install the entire group
10214 * (through the sibling list, which is still in-tact), we can
10215 * end up with siblings installed in the wrong context.
10217 * By installing siblings first we NO-OP because they're not
10218 * reachable through the group lists.
10220 list_for_each_entry(sibling, &group_leader->sibling_list,
10222 perf_event__state_init(sibling);
10223 perf_install_in_context(ctx, sibling, sibling->cpu);
10228 * Removing from the context ends up with disabled
10229 * event. What we want here is event in the initial
10230 * startup state, ready to be add into new context.
10232 perf_event__state_init(group_leader);
10233 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10238 * Precalculate sample_data sizes; do while holding ctx::mutex such
10239 * that we're serialized against further additions and before
10240 * perf_install_in_context() which is the point the event is active and
10241 * can use these values.
10243 perf_event__header_size(event);
10244 perf_event__id_header_size(event);
10246 event->owner = current;
10248 perf_install_in_context(ctx, event, event->cpu);
10249 perf_unpin_context(ctx);
10252 perf_event_ctx_unlock(group_leader, gctx);
10253 mutex_unlock(&ctx->mutex);
10256 mutex_unlock(&task->signal->cred_guard_mutex);
10257 put_task_struct(task);
10260 mutex_lock(¤t->perf_event_mutex);
10261 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10262 mutex_unlock(¤t->perf_event_mutex);
10265 * Drop the reference on the group_event after placing the
10266 * new event on the sibling_list. This ensures destruction
10267 * of the group leader will find the pointer to itself in
10268 * perf_group_detach().
10271 fd_install(event_fd, event_file);
10276 perf_event_ctx_unlock(group_leader, gctx);
10277 mutex_unlock(&ctx->mutex);
10281 perf_unpin_context(ctx);
10285 * If event_file is set, the fput() above will have called ->release()
10286 * and that will take care of freeing the event.
10292 mutex_unlock(&task->signal->cred_guard_mutex);
10295 put_task_struct(task);
10299 put_unused_fd(event_fd);
10304 * perf_event_create_kernel_counter
10306 * @attr: attributes of the counter to create
10307 * @cpu: cpu in which the counter is bound
10308 * @task: task to profile (NULL for percpu)
10310 struct perf_event *
10311 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10312 struct task_struct *task,
10313 perf_overflow_handler_t overflow_handler,
10316 struct perf_event_context *ctx;
10317 struct perf_event *event;
10321 * Get the target context (task or percpu):
10324 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10325 overflow_handler, context, -1);
10326 if (IS_ERR(event)) {
10327 err = PTR_ERR(event);
10331 /* Mark owner so we could distinguish it from user events. */
10332 event->owner = TASK_TOMBSTONE;
10334 ctx = find_get_context(event->pmu, task, event);
10336 err = PTR_ERR(ctx);
10340 WARN_ON_ONCE(ctx->parent_ctx);
10341 mutex_lock(&ctx->mutex);
10342 if (ctx->task == TASK_TOMBSTONE) {
10349 * Check if the @cpu we're creating an event for is online.
10351 * We use the perf_cpu_context::ctx::mutex to serialize against
10352 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10354 struct perf_cpu_context *cpuctx =
10355 container_of(ctx, struct perf_cpu_context, ctx);
10356 if (!cpuctx->online) {
10362 if (!exclusive_event_installable(event, ctx)) {
10367 perf_install_in_context(ctx, event, cpu);
10368 perf_unpin_context(ctx);
10369 mutex_unlock(&ctx->mutex);
10374 mutex_unlock(&ctx->mutex);
10375 perf_unpin_context(ctx);
10380 return ERR_PTR(err);
10382 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10384 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10386 struct perf_event_context *src_ctx;
10387 struct perf_event_context *dst_ctx;
10388 struct perf_event *event, *tmp;
10391 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10392 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10395 * See perf_event_ctx_lock() for comments on the details
10396 * of swizzling perf_event::ctx.
10398 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10399 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10401 perf_remove_from_context(event, 0);
10402 unaccount_event_cpu(event, src_cpu);
10404 list_add(&event->migrate_entry, &events);
10408 * Wait for the events to quiesce before re-instating them.
10413 * Re-instate events in 2 passes.
10415 * Skip over group leaders and only install siblings on this first
10416 * pass, siblings will not get enabled without a leader, however a
10417 * leader will enable its siblings, even if those are still on the old
10420 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10421 if (event->group_leader == event)
10424 list_del(&event->migrate_entry);
10425 if (event->state >= PERF_EVENT_STATE_OFF)
10426 event->state = PERF_EVENT_STATE_INACTIVE;
10427 account_event_cpu(event, dst_cpu);
10428 perf_install_in_context(dst_ctx, event, dst_cpu);
10433 * Once all the siblings are setup properly, install the group leaders
10436 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10437 list_del(&event->migrate_entry);
10438 if (event->state >= PERF_EVENT_STATE_OFF)
10439 event->state = PERF_EVENT_STATE_INACTIVE;
10440 account_event_cpu(event, dst_cpu);
10441 perf_install_in_context(dst_ctx, event, dst_cpu);
10444 mutex_unlock(&dst_ctx->mutex);
10445 mutex_unlock(&src_ctx->mutex);
10447 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10449 static void sync_child_event(struct perf_event *child_event,
10450 struct task_struct *child)
10452 struct perf_event *parent_event = child_event->parent;
10455 if (child_event->attr.inherit_stat)
10456 perf_event_read_event(child_event, child);
10458 child_val = perf_event_count(child_event);
10461 * Add back the child's count to the parent's count:
10463 atomic64_add(child_val, &parent_event->child_count);
10464 atomic64_add(child_event->total_time_enabled,
10465 &parent_event->child_total_time_enabled);
10466 atomic64_add(child_event->total_time_running,
10467 &parent_event->child_total_time_running);
10471 perf_event_exit_event(struct perf_event *child_event,
10472 struct perf_event_context *child_ctx,
10473 struct task_struct *child)
10475 struct perf_event *parent_event = child_event->parent;
10478 * Do not destroy the 'original' grouping; because of the context
10479 * switch optimization the original events could've ended up in a
10480 * random child task.
10482 * If we were to destroy the original group, all group related
10483 * operations would cease to function properly after this random
10486 * Do destroy all inherited groups, we don't care about those
10487 * and being thorough is better.
10489 raw_spin_lock_irq(&child_ctx->lock);
10490 WARN_ON_ONCE(child_ctx->is_active);
10493 perf_group_detach(child_event);
10494 list_del_event(child_event, child_ctx);
10495 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
10496 raw_spin_unlock_irq(&child_ctx->lock);
10499 * Parent events are governed by their filedesc, retain them.
10501 if (!parent_event) {
10502 perf_event_wakeup(child_event);
10506 * Child events can be cleaned up.
10509 sync_child_event(child_event, child);
10512 * Remove this event from the parent's list
10514 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10515 mutex_lock(&parent_event->child_mutex);
10516 list_del_init(&child_event->child_list);
10517 mutex_unlock(&parent_event->child_mutex);
10520 * Kick perf_poll() for is_event_hup().
10522 perf_event_wakeup(parent_event);
10523 free_event(child_event);
10524 put_event(parent_event);
10527 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10529 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10530 struct perf_event *child_event, *next;
10532 WARN_ON_ONCE(child != current);
10534 child_ctx = perf_pin_task_context(child, ctxn);
10539 * In order to reduce the amount of tricky in ctx tear-down, we hold
10540 * ctx::mutex over the entire thing. This serializes against almost
10541 * everything that wants to access the ctx.
10543 * The exception is sys_perf_event_open() /
10544 * perf_event_create_kernel_count() which does find_get_context()
10545 * without ctx::mutex (it cannot because of the move_group double mutex
10546 * lock thing). See the comments in perf_install_in_context().
10548 mutex_lock(&child_ctx->mutex);
10551 * In a single ctx::lock section, de-schedule the events and detach the
10552 * context from the task such that we cannot ever get it scheduled back
10555 raw_spin_lock_irq(&child_ctx->lock);
10556 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10559 * Now that the context is inactive, destroy the task <-> ctx relation
10560 * and mark the context dead.
10562 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10563 put_ctx(child_ctx); /* cannot be last */
10564 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10565 put_task_struct(current); /* cannot be last */
10567 clone_ctx = unclone_ctx(child_ctx);
10568 raw_spin_unlock_irq(&child_ctx->lock);
10571 put_ctx(clone_ctx);
10574 * Report the task dead after unscheduling the events so that we
10575 * won't get any samples after PERF_RECORD_EXIT. We can however still
10576 * get a few PERF_RECORD_READ events.
10578 perf_event_task(child, child_ctx, 0);
10580 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10581 perf_event_exit_event(child_event, child_ctx, child);
10583 mutex_unlock(&child_ctx->mutex);
10585 put_ctx(child_ctx);
10589 * When a child task exits, feed back event values to parent events.
10591 * Can be called with cred_guard_mutex held when called from
10592 * install_exec_creds().
10594 void perf_event_exit_task(struct task_struct *child)
10596 struct perf_event *event, *tmp;
10599 mutex_lock(&child->perf_event_mutex);
10600 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10602 list_del_init(&event->owner_entry);
10605 * Ensure the list deletion is visible before we clear
10606 * the owner, closes a race against perf_release() where
10607 * we need to serialize on the owner->perf_event_mutex.
10609 smp_store_release(&event->owner, NULL);
10611 mutex_unlock(&child->perf_event_mutex);
10613 for_each_task_context_nr(ctxn)
10614 perf_event_exit_task_context(child, ctxn);
10617 * The perf_event_exit_task_context calls perf_event_task
10618 * with child's task_ctx, which generates EXIT events for
10619 * child contexts and sets child->perf_event_ctxp[] to NULL.
10620 * At this point we need to send EXIT events to cpu contexts.
10622 perf_event_task(child, NULL, 0);
10625 static void perf_free_event(struct perf_event *event,
10626 struct perf_event_context *ctx)
10628 struct perf_event *parent = event->parent;
10630 if (WARN_ON_ONCE(!parent))
10633 mutex_lock(&parent->child_mutex);
10634 list_del_init(&event->child_list);
10635 mutex_unlock(&parent->child_mutex);
10639 raw_spin_lock_irq(&ctx->lock);
10640 perf_group_detach(event);
10641 list_del_event(event, ctx);
10642 raw_spin_unlock_irq(&ctx->lock);
10647 * Free an unexposed, unused context as created by inheritance by
10648 * perf_event_init_task below, used by fork() in case of fail.
10650 * Not all locks are strictly required, but take them anyway to be nice and
10651 * help out with the lockdep assertions.
10653 void perf_event_free_task(struct task_struct *task)
10655 struct perf_event_context *ctx;
10656 struct perf_event *event, *tmp;
10659 for_each_task_context_nr(ctxn) {
10660 ctx = task->perf_event_ctxp[ctxn];
10664 mutex_lock(&ctx->mutex);
10665 raw_spin_lock_irq(&ctx->lock);
10667 * Destroy the task <-> ctx relation and mark the context dead.
10669 * This is important because even though the task hasn't been
10670 * exposed yet the context has been (through child_list).
10672 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10673 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10674 put_task_struct(task); /* cannot be last */
10675 raw_spin_unlock_irq(&ctx->lock);
10677 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10678 perf_free_event(event, ctx);
10680 mutex_unlock(&ctx->mutex);
10685 void perf_event_delayed_put(struct task_struct *task)
10689 for_each_task_context_nr(ctxn)
10690 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10693 struct file *perf_event_get(unsigned int fd)
10697 file = fget_raw(fd);
10699 return ERR_PTR(-EBADF);
10701 if (file->f_op != &perf_fops) {
10703 return ERR_PTR(-EBADF);
10709 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10712 return ERR_PTR(-EINVAL);
10714 return &event->attr;
10718 * Inherit a event from parent task to child task.
10721 * - valid pointer on success
10722 * - NULL for orphaned events
10723 * - IS_ERR() on error
10725 static struct perf_event *
10726 inherit_event(struct perf_event *parent_event,
10727 struct task_struct *parent,
10728 struct perf_event_context *parent_ctx,
10729 struct task_struct *child,
10730 struct perf_event *group_leader,
10731 struct perf_event_context *child_ctx)
10733 enum perf_event_state parent_state = parent_event->state;
10734 struct perf_event *child_event;
10735 unsigned long flags;
10738 * Instead of creating recursive hierarchies of events,
10739 * we link inherited events back to the original parent,
10740 * which has a filp for sure, which we use as the reference
10743 if (parent_event->parent)
10744 parent_event = parent_event->parent;
10746 child_event = perf_event_alloc(&parent_event->attr,
10749 group_leader, parent_event,
10751 if (IS_ERR(child_event))
10752 return child_event;
10755 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
10756 !child_ctx->task_ctx_data) {
10757 struct pmu *pmu = child_event->pmu;
10759 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
10761 if (!child_ctx->task_ctx_data) {
10762 free_event(child_event);
10768 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10769 * must be under the same lock in order to serialize against
10770 * perf_event_release_kernel(), such that either we must observe
10771 * is_orphaned_event() or they will observe us on the child_list.
10773 mutex_lock(&parent_event->child_mutex);
10774 if (is_orphaned_event(parent_event) ||
10775 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10776 mutex_unlock(&parent_event->child_mutex);
10777 /* task_ctx_data is freed with child_ctx */
10778 free_event(child_event);
10782 get_ctx(child_ctx);
10785 * Make the child state follow the state of the parent event,
10786 * not its attr.disabled bit. We hold the parent's mutex,
10787 * so we won't race with perf_event_{en, dis}able_family.
10789 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10790 child_event->state = PERF_EVENT_STATE_INACTIVE;
10792 child_event->state = PERF_EVENT_STATE_OFF;
10794 if (parent_event->attr.freq) {
10795 u64 sample_period = parent_event->hw.sample_period;
10796 struct hw_perf_event *hwc = &child_event->hw;
10798 hwc->sample_period = sample_period;
10799 hwc->last_period = sample_period;
10801 local64_set(&hwc->period_left, sample_period);
10804 child_event->ctx = child_ctx;
10805 child_event->overflow_handler = parent_event->overflow_handler;
10806 child_event->overflow_handler_context
10807 = parent_event->overflow_handler_context;
10810 * Precalculate sample_data sizes
10812 perf_event__header_size(child_event);
10813 perf_event__id_header_size(child_event);
10816 * Link it up in the child's context:
10818 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10819 add_event_to_ctx(child_event, child_ctx);
10820 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10823 * Link this into the parent event's child list
10825 list_add_tail(&child_event->child_list, &parent_event->child_list);
10826 mutex_unlock(&parent_event->child_mutex);
10828 return child_event;
10832 * Inherits an event group.
10834 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10835 * This matches with perf_event_release_kernel() removing all child events.
10841 static int inherit_group(struct perf_event *parent_event,
10842 struct task_struct *parent,
10843 struct perf_event_context *parent_ctx,
10844 struct task_struct *child,
10845 struct perf_event_context *child_ctx)
10847 struct perf_event *leader;
10848 struct perf_event *sub;
10849 struct perf_event *child_ctr;
10851 leader = inherit_event(parent_event, parent, parent_ctx,
10852 child, NULL, child_ctx);
10853 if (IS_ERR(leader))
10854 return PTR_ERR(leader);
10856 * @leader can be NULL here because of is_orphaned_event(). In this
10857 * case inherit_event() will create individual events, similar to what
10858 * perf_group_detach() would do anyway.
10860 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10861 child_ctr = inherit_event(sub, parent, parent_ctx,
10862 child, leader, child_ctx);
10863 if (IS_ERR(child_ctr))
10864 return PTR_ERR(child_ctr);
10870 * Creates the child task context and tries to inherit the event-group.
10872 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10873 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10874 * consistent with perf_event_release_kernel() removing all child events.
10881 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10882 struct perf_event_context *parent_ctx,
10883 struct task_struct *child, int ctxn,
10884 int *inherited_all)
10887 struct perf_event_context *child_ctx;
10889 if (!event->attr.inherit) {
10890 *inherited_all = 0;
10894 child_ctx = child->perf_event_ctxp[ctxn];
10897 * This is executed from the parent task context, so
10898 * inherit events that have been marked for cloning.
10899 * First allocate and initialize a context for the
10902 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10906 child->perf_event_ctxp[ctxn] = child_ctx;
10909 ret = inherit_group(event, parent, parent_ctx,
10913 *inherited_all = 0;
10919 * Initialize the perf_event context in task_struct
10921 static int perf_event_init_context(struct task_struct *child, int ctxn)
10923 struct perf_event_context *child_ctx, *parent_ctx;
10924 struct perf_event_context *cloned_ctx;
10925 struct perf_event *event;
10926 struct task_struct *parent = current;
10927 int inherited_all = 1;
10928 unsigned long flags;
10931 if (likely(!parent->perf_event_ctxp[ctxn]))
10935 * If the parent's context is a clone, pin it so it won't get
10936 * swapped under us.
10938 parent_ctx = perf_pin_task_context(parent, ctxn);
10943 * No need to check if parent_ctx != NULL here; since we saw
10944 * it non-NULL earlier, the only reason for it to become NULL
10945 * is if we exit, and since we're currently in the middle of
10946 * a fork we can't be exiting at the same time.
10950 * Lock the parent list. No need to lock the child - not PID
10951 * hashed yet and not running, so nobody can access it.
10953 mutex_lock(&parent_ctx->mutex);
10956 * We dont have to disable NMIs - we are only looking at
10957 * the list, not manipulating it:
10959 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10960 ret = inherit_task_group(event, parent, parent_ctx,
10961 child, ctxn, &inherited_all);
10967 * We can't hold ctx->lock when iterating the ->flexible_group list due
10968 * to allocations, but we need to prevent rotation because
10969 * rotate_ctx() will change the list from interrupt context.
10971 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10972 parent_ctx->rotate_disable = 1;
10973 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10975 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10976 ret = inherit_task_group(event, parent, parent_ctx,
10977 child, ctxn, &inherited_all);
10982 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10983 parent_ctx->rotate_disable = 0;
10985 child_ctx = child->perf_event_ctxp[ctxn];
10987 if (child_ctx && inherited_all) {
10989 * Mark the child context as a clone of the parent
10990 * context, or of whatever the parent is a clone of.
10992 * Note that if the parent is a clone, the holding of
10993 * parent_ctx->lock avoids it from being uncloned.
10995 cloned_ctx = parent_ctx->parent_ctx;
10997 child_ctx->parent_ctx = cloned_ctx;
10998 child_ctx->parent_gen = parent_ctx->parent_gen;
11000 child_ctx->parent_ctx = parent_ctx;
11001 child_ctx->parent_gen = parent_ctx->generation;
11003 get_ctx(child_ctx->parent_ctx);
11006 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11008 mutex_unlock(&parent_ctx->mutex);
11010 perf_unpin_context(parent_ctx);
11011 put_ctx(parent_ctx);
11017 * Initialize the perf_event context in task_struct
11019 int perf_event_init_task(struct task_struct *child)
11023 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11024 mutex_init(&child->perf_event_mutex);
11025 INIT_LIST_HEAD(&child->perf_event_list);
11027 for_each_task_context_nr(ctxn) {
11028 ret = perf_event_init_context(child, ctxn);
11030 perf_event_free_task(child);
11038 static void __init perf_event_init_all_cpus(void)
11040 struct swevent_htable *swhash;
11043 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11045 for_each_possible_cpu(cpu) {
11046 swhash = &per_cpu(swevent_htable, cpu);
11047 mutex_init(&swhash->hlist_mutex);
11048 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11050 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11051 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11053 #ifdef CONFIG_CGROUP_PERF
11054 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11056 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11060 void perf_swevent_init_cpu(unsigned int cpu)
11062 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11064 mutex_lock(&swhash->hlist_mutex);
11065 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11066 struct swevent_hlist *hlist;
11068 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11070 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11072 mutex_unlock(&swhash->hlist_mutex);
11075 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11076 static void __perf_event_exit_context(void *__info)
11078 struct perf_event_context *ctx = __info;
11079 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11080 struct perf_event *event;
11082 raw_spin_lock(&ctx->lock);
11083 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11084 list_for_each_entry(event, &ctx->event_list, event_entry)
11085 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11086 raw_spin_unlock(&ctx->lock);
11089 static void perf_event_exit_cpu_context(int cpu)
11091 struct perf_cpu_context *cpuctx;
11092 struct perf_event_context *ctx;
11095 mutex_lock(&pmus_lock);
11096 list_for_each_entry(pmu, &pmus, entry) {
11097 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11098 ctx = &cpuctx->ctx;
11100 mutex_lock(&ctx->mutex);
11101 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11102 cpuctx->online = 0;
11103 mutex_unlock(&ctx->mutex);
11105 cpumask_clear_cpu(cpu, perf_online_mask);
11106 mutex_unlock(&pmus_lock);
11110 static void perf_event_exit_cpu_context(int cpu) { }
11114 int perf_event_init_cpu(unsigned int cpu)
11116 struct perf_cpu_context *cpuctx;
11117 struct perf_event_context *ctx;
11120 perf_swevent_init_cpu(cpu);
11122 mutex_lock(&pmus_lock);
11123 cpumask_set_cpu(cpu, perf_online_mask);
11124 list_for_each_entry(pmu, &pmus, entry) {
11125 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11126 ctx = &cpuctx->ctx;
11128 mutex_lock(&ctx->mutex);
11129 cpuctx->online = 1;
11130 mutex_unlock(&ctx->mutex);
11132 mutex_unlock(&pmus_lock);
11137 int perf_event_exit_cpu(unsigned int cpu)
11139 perf_event_exit_cpu_context(cpu);
11144 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11148 for_each_online_cpu(cpu)
11149 perf_event_exit_cpu(cpu);
11155 * Run the perf reboot notifier at the very last possible moment so that
11156 * the generic watchdog code runs as long as possible.
11158 static struct notifier_block perf_reboot_notifier = {
11159 .notifier_call = perf_reboot,
11160 .priority = INT_MIN,
11163 void __init perf_event_init(void)
11167 idr_init(&pmu_idr);
11169 perf_event_init_all_cpus();
11170 init_srcu_struct(&pmus_srcu);
11171 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11172 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11173 perf_pmu_register(&perf_task_clock, NULL, -1);
11174 perf_tp_register();
11175 perf_event_init_cpu(smp_processor_id());
11176 register_reboot_notifier(&perf_reboot_notifier);
11178 ret = init_hw_breakpoint();
11179 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11182 * Build time assertion that we keep the data_head at the intended
11183 * location. IOW, validation we got the __reserved[] size right.
11185 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11189 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11192 struct perf_pmu_events_attr *pmu_attr =
11193 container_of(attr, struct perf_pmu_events_attr, attr);
11195 if (pmu_attr->event_str)
11196 return sprintf(page, "%s\n", pmu_attr->event_str);
11200 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11202 static int __init perf_event_sysfs_init(void)
11207 mutex_lock(&pmus_lock);
11209 ret = bus_register(&pmu_bus);
11213 list_for_each_entry(pmu, &pmus, entry) {
11214 if (!pmu->name || pmu->type < 0)
11217 ret = pmu_dev_alloc(pmu);
11218 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11220 pmu_bus_running = 1;
11224 mutex_unlock(&pmus_lock);
11228 device_initcall(perf_event_sysfs_init);
11230 #ifdef CONFIG_CGROUP_PERF
11231 static struct cgroup_subsys_state *
11232 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11234 struct perf_cgroup *jc;
11236 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11238 return ERR_PTR(-ENOMEM);
11240 jc->info = alloc_percpu(struct perf_cgroup_info);
11243 return ERR_PTR(-ENOMEM);
11249 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11251 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11253 free_percpu(jc->info);
11257 static int __perf_cgroup_move(void *info)
11259 struct task_struct *task = info;
11261 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11266 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11268 struct task_struct *task;
11269 struct cgroup_subsys_state *css;
11271 cgroup_taskset_for_each(task, css, tset)
11272 task_function_call(task, __perf_cgroup_move, task);
11275 struct cgroup_subsys perf_event_cgrp_subsys = {
11276 .css_alloc = perf_cgroup_css_alloc,
11277 .css_free = perf_cgroup_css_free,
11278 .attach = perf_cgroup_attach,
11280 * Implicitly enable on dfl hierarchy so that perf events can
11281 * always be filtered by cgroup2 path as long as perf_event
11282 * controller is not mounted on a legacy hierarchy.
11284 .implicit_on_dfl = true,
11287 #endif /* CONFIG_CGROUP_PERF */