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 bool 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,
440 int perf_cpu = sysctl_perf_cpu_time_max_percent;
442 * If throttling is disabled don't allow the write:
444 if (write && (perf_cpu == 100 || perf_cpu == 0))
447 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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 for_each_sibling_event(sibling, leader)
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 = cpuctx->cgrp;
728 struct cgroup_subsys_state *css;
731 for (css = &cgrp->css; css; css = css->parent) {
732 cgrp = container_of(css, struct perf_cgroup, css);
733 __update_cgrp_time(cgrp);
738 static inline void update_cgrp_time_from_event(struct perf_event *event)
740 struct perf_cgroup *cgrp;
743 * ensure we access cgroup data only when needed and
744 * when we know the cgroup is pinned (css_get)
746 if (!is_cgroup_event(event))
749 cgrp = perf_cgroup_from_task(current, event->ctx);
751 * Do not update time when cgroup is not active
753 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
754 __update_cgrp_time(event->cgrp);
758 perf_cgroup_set_timestamp(struct task_struct *task,
759 struct perf_event_context *ctx)
761 struct perf_cgroup *cgrp;
762 struct perf_cgroup_info *info;
763 struct cgroup_subsys_state *css;
766 * ctx->lock held by caller
767 * ensure we do not access cgroup data
768 * unless we have the cgroup pinned (css_get)
770 if (!task || !ctx->nr_cgroups)
773 cgrp = perf_cgroup_from_task(task, ctx);
775 for (css = &cgrp->css; css; css = css->parent) {
776 cgrp = container_of(css, struct perf_cgroup, css);
777 info = this_cpu_ptr(cgrp->info);
778 info->timestamp = ctx->timestamp;
782 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
784 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
785 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
788 * reschedule events based on the cgroup constraint of task.
790 * mode SWOUT : schedule out everything
791 * mode SWIN : schedule in based on cgroup for next
793 static void perf_cgroup_switch(struct task_struct *task, int mode)
795 struct perf_cpu_context *cpuctx;
796 struct list_head *list;
800 * Disable interrupts and preemption to avoid this CPU's
801 * cgrp_cpuctx_entry to change under us.
803 local_irq_save(flags);
805 list = this_cpu_ptr(&cgrp_cpuctx_list);
806 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
807 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
809 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
810 perf_pmu_disable(cpuctx->ctx.pmu);
812 if (mode & PERF_CGROUP_SWOUT) {
813 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
815 * must not be done before ctxswout due
816 * to event_filter_match() in event_sched_out()
821 if (mode & PERF_CGROUP_SWIN) {
822 WARN_ON_ONCE(cpuctx->cgrp);
824 * set cgrp before ctxsw in to allow
825 * event_filter_match() to not have to pass
827 * we pass the cpuctx->ctx to perf_cgroup_from_task()
828 * because cgorup events are only per-cpu
830 cpuctx->cgrp = perf_cgroup_from_task(task,
832 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
834 perf_pmu_enable(cpuctx->ctx.pmu);
835 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
838 local_irq_restore(flags);
841 static inline void perf_cgroup_sched_out(struct task_struct *task,
842 struct task_struct *next)
844 struct perf_cgroup *cgrp1;
845 struct perf_cgroup *cgrp2 = NULL;
849 * we come here when we know perf_cgroup_events > 0
850 * we do not need to pass the ctx here because we know
851 * we are holding the rcu lock
853 cgrp1 = perf_cgroup_from_task(task, NULL);
854 cgrp2 = perf_cgroup_from_task(next, NULL);
857 * only schedule out current cgroup events if we know
858 * that we are switching to a different cgroup. Otherwise,
859 * do no touch the cgroup events.
862 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
867 static inline void perf_cgroup_sched_in(struct task_struct *prev,
868 struct task_struct *task)
870 struct perf_cgroup *cgrp1;
871 struct perf_cgroup *cgrp2 = NULL;
875 * we come here when we know perf_cgroup_events > 0
876 * we do not need to pass the ctx here because we know
877 * we are holding the rcu lock
879 cgrp1 = perf_cgroup_from_task(task, NULL);
880 cgrp2 = perf_cgroup_from_task(prev, NULL);
883 * only need to schedule in cgroup events if we are changing
884 * cgroup during ctxsw. Cgroup events were not scheduled
885 * out of ctxsw out if that was not the case.
888 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
893 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
894 struct perf_event_attr *attr,
895 struct perf_event *group_leader)
897 struct perf_cgroup *cgrp;
898 struct cgroup_subsys_state *css;
899 struct fd f = fdget(fd);
905 css = css_tryget_online_from_dir(f.file->f_path.dentry,
906 &perf_event_cgrp_subsys);
912 cgrp = container_of(css, struct perf_cgroup, css);
916 * all events in a group must monitor
917 * the same cgroup because a task belongs
918 * to only one perf cgroup at a time
920 if (group_leader && group_leader->cgrp != cgrp) {
921 perf_detach_cgroup(event);
930 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
932 struct perf_cgroup_info *t;
933 t = per_cpu_ptr(event->cgrp->info, event->cpu);
934 event->shadow_ctx_time = now - t->timestamp;
938 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
939 * cleared when last cgroup event is removed.
942 list_update_cgroup_event(struct perf_event *event,
943 struct perf_event_context *ctx, bool add)
945 struct perf_cpu_context *cpuctx;
946 struct list_head *cpuctx_entry;
948 if (!is_cgroup_event(event))
952 * Because cgroup events are always per-cpu events,
953 * this will always be called from the right CPU.
955 cpuctx = __get_cpu_context(ctx);
958 * Since setting cpuctx->cgrp is conditional on the current @cgrp
959 * matching the event's cgroup, we must do this for every new event,
960 * because if the first would mismatch, the second would not try again
961 * and we would leave cpuctx->cgrp unset.
963 if (add && !cpuctx->cgrp) {
964 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
966 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
970 if (add && ctx->nr_cgroups++)
972 else if (!add && --ctx->nr_cgroups)
975 /* no cgroup running */
979 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
981 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
983 list_del(cpuctx_entry);
986 #else /* !CONFIG_CGROUP_PERF */
989 perf_cgroup_match(struct perf_event *event)
994 static inline void perf_detach_cgroup(struct perf_event *event)
997 static inline int is_cgroup_event(struct perf_event *event)
1002 static inline void update_cgrp_time_from_event(struct perf_event *event)
1006 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1010 static inline void perf_cgroup_sched_out(struct task_struct *task,
1011 struct task_struct *next)
1015 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1016 struct task_struct *task)
1020 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1021 struct perf_event_attr *attr,
1022 struct perf_event *group_leader)
1028 perf_cgroup_set_timestamp(struct task_struct *task,
1029 struct perf_event_context *ctx)
1034 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1039 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1043 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1049 list_update_cgroup_event(struct perf_event *event,
1050 struct perf_event_context *ctx, bool add)
1057 * set default to be dependent on timer tick just
1058 * like original code
1060 #define PERF_CPU_HRTIMER (1000 / HZ)
1062 * function must be called with interrupts disabled
1064 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1066 struct perf_cpu_context *cpuctx;
1069 lockdep_assert_irqs_disabled();
1071 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1072 rotations = perf_rotate_context(cpuctx);
1074 raw_spin_lock(&cpuctx->hrtimer_lock);
1076 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1078 cpuctx->hrtimer_active = 0;
1079 raw_spin_unlock(&cpuctx->hrtimer_lock);
1081 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1084 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1086 struct hrtimer *timer = &cpuctx->hrtimer;
1087 struct pmu *pmu = cpuctx->ctx.pmu;
1090 /* no multiplexing needed for SW PMU */
1091 if (pmu->task_ctx_nr == perf_sw_context)
1095 * check default is sane, if not set then force to
1096 * default interval (1/tick)
1098 interval = pmu->hrtimer_interval_ms;
1100 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1102 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1104 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1105 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1106 timer->function = perf_mux_hrtimer_handler;
1109 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1111 struct hrtimer *timer = &cpuctx->hrtimer;
1112 struct pmu *pmu = cpuctx->ctx.pmu;
1113 unsigned long flags;
1115 /* not for SW PMU */
1116 if (pmu->task_ctx_nr == perf_sw_context)
1119 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1120 if (!cpuctx->hrtimer_active) {
1121 cpuctx->hrtimer_active = 1;
1122 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1123 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1125 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1130 void perf_pmu_disable(struct pmu *pmu)
1132 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1134 pmu->pmu_disable(pmu);
1137 void perf_pmu_enable(struct pmu *pmu)
1139 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1141 pmu->pmu_enable(pmu);
1144 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1147 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1148 * perf_event_task_tick() are fully serialized because they're strictly cpu
1149 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1150 * disabled, while perf_event_task_tick is called from IRQ context.
1152 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1154 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1156 lockdep_assert_irqs_disabled();
1158 WARN_ON(!list_empty(&ctx->active_ctx_list));
1160 list_add(&ctx->active_ctx_list, head);
1163 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1165 lockdep_assert_irqs_disabled();
1167 WARN_ON(list_empty(&ctx->active_ctx_list));
1169 list_del_init(&ctx->active_ctx_list);
1172 static void get_ctx(struct perf_event_context *ctx)
1174 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1177 static void free_ctx(struct rcu_head *head)
1179 struct perf_event_context *ctx;
1181 ctx = container_of(head, struct perf_event_context, rcu_head);
1182 kfree(ctx->task_ctx_data);
1186 static void put_ctx(struct perf_event_context *ctx)
1188 if (atomic_dec_and_test(&ctx->refcount)) {
1189 if (ctx->parent_ctx)
1190 put_ctx(ctx->parent_ctx);
1191 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1192 put_task_struct(ctx->task);
1193 call_rcu(&ctx->rcu_head, free_ctx);
1198 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1199 * perf_pmu_migrate_context() we need some magic.
1201 * Those places that change perf_event::ctx will hold both
1202 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1204 * Lock ordering is by mutex address. There are two other sites where
1205 * perf_event_context::mutex nests and those are:
1207 * - perf_event_exit_task_context() [ child , 0 ]
1208 * perf_event_exit_event()
1209 * put_event() [ parent, 1 ]
1211 * - perf_event_init_context() [ parent, 0 ]
1212 * inherit_task_group()
1215 * perf_event_alloc()
1217 * perf_try_init_event() [ child , 1 ]
1219 * While it appears there is an obvious deadlock here -- the parent and child
1220 * nesting levels are inverted between the two. This is in fact safe because
1221 * life-time rules separate them. That is an exiting task cannot fork, and a
1222 * spawning task cannot (yet) exit.
1224 * But remember that that these are parent<->child context relations, and
1225 * migration does not affect children, therefore these two orderings should not
1228 * The change in perf_event::ctx does not affect children (as claimed above)
1229 * because the sys_perf_event_open() case will install a new event and break
1230 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1231 * concerned with cpuctx and that doesn't have children.
1233 * The places that change perf_event::ctx will issue:
1235 * perf_remove_from_context();
1236 * synchronize_rcu();
1237 * perf_install_in_context();
1239 * to affect the change. The remove_from_context() + synchronize_rcu() should
1240 * quiesce the event, after which we can install it in the new location. This
1241 * means that only external vectors (perf_fops, prctl) can perturb the event
1242 * while in transit. Therefore all such accessors should also acquire
1243 * perf_event_context::mutex to serialize against this.
1245 * However; because event->ctx can change while we're waiting to acquire
1246 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1251 * task_struct::perf_event_mutex
1252 * perf_event_context::mutex
1253 * perf_event::child_mutex;
1254 * perf_event_context::lock
1255 * perf_event::mmap_mutex
1260 * cpuctx->mutex / perf_event_context::mutex
1262 static struct perf_event_context *
1263 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1265 struct perf_event_context *ctx;
1269 ctx = READ_ONCE(event->ctx);
1270 if (!atomic_inc_not_zero(&ctx->refcount)) {
1276 mutex_lock_nested(&ctx->mutex, nesting);
1277 if (event->ctx != ctx) {
1278 mutex_unlock(&ctx->mutex);
1286 static inline struct perf_event_context *
1287 perf_event_ctx_lock(struct perf_event *event)
1289 return perf_event_ctx_lock_nested(event, 0);
1292 static void perf_event_ctx_unlock(struct perf_event *event,
1293 struct perf_event_context *ctx)
1295 mutex_unlock(&ctx->mutex);
1300 * This must be done under the ctx->lock, such as to serialize against
1301 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1302 * calling scheduler related locks and ctx->lock nests inside those.
1304 static __must_check struct perf_event_context *
1305 unclone_ctx(struct perf_event_context *ctx)
1307 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1309 lockdep_assert_held(&ctx->lock);
1312 ctx->parent_ctx = NULL;
1318 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1323 * only top level events have the pid namespace they were created in
1326 event = event->parent;
1328 nr = __task_pid_nr_ns(p, type, event->ns);
1329 /* avoid -1 if it is idle thread or runs in another ns */
1330 if (!nr && !pid_alive(p))
1335 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1337 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1340 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1342 return perf_event_pid_type(event, p, PIDTYPE_PID);
1346 * If we inherit events we want to return the parent event id
1349 static u64 primary_event_id(struct perf_event *event)
1354 id = event->parent->id;
1360 * Get the perf_event_context for a task and lock it.
1362 * This has to cope with with the fact that until it is locked,
1363 * the context could get moved to another task.
1365 static struct perf_event_context *
1366 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1368 struct perf_event_context *ctx;
1372 * One of the few rules of preemptible RCU is that one cannot do
1373 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1374 * part of the read side critical section was irqs-enabled -- see
1375 * rcu_read_unlock_special().
1377 * Since ctx->lock nests under rq->lock we must ensure the entire read
1378 * side critical section has interrupts disabled.
1380 local_irq_save(*flags);
1382 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1385 * If this context is a clone of another, it might
1386 * get swapped for another underneath us by
1387 * perf_event_task_sched_out, though the
1388 * rcu_read_lock() protects us from any context
1389 * getting freed. Lock the context and check if it
1390 * got swapped before we could get the lock, and retry
1391 * if so. If we locked the right context, then it
1392 * can't get swapped on us any more.
1394 raw_spin_lock(&ctx->lock);
1395 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1396 raw_spin_unlock(&ctx->lock);
1398 local_irq_restore(*flags);
1402 if (ctx->task == TASK_TOMBSTONE ||
1403 !atomic_inc_not_zero(&ctx->refcount)) {
1404 raw_spin_unlock(&ctx->lock);
1407 WARN_ON_ONCE(ctx->task != task);
1412 local_irq_restore(*flags);
1417 * Get the context for a task and increment its pin_count so it
1418 * can't get swapped to another task. This also increments its
1419 * reference count so that the context can't get freed.
1421 static struct perf_event_context *
1422 perf_pin_task_context(struct task_struct *task, int ctxn)
1424 struct perf_event_context *ctx;
1425 unsigned long flags;
1427 ctx = perf_lock_task_context(task, ctxn, &flags);
1430 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1435 static void perf_unpin_context(struct perf_event_context *ctx)
1437 unsigned long flags;
1439 raw_spin_lock_irqsave(&ctx->lock, flags);
1441 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1445 * Update the record of the current time in a context.
1447 static void update_context_time(struct perf_event_context *ctx)
1449 u64 now = perf_clock();
1451 ctx->time += now - ctx->timestamp;
1452 ctx->timestamp = now;
1455 static u64 perf_event_time(struct perf_event *event)
1457 struct perf_event_context *ctx = event->ctx;
1459 if (is_cgroup_event(event))
1460 return perf_cgroup_event_time(event);
1462 return ctx ? ctx->time : 0;
1465 static enum event_type_t get_event_type(struct perf_event *event)
1467 struct perf_event_context *ctx = event->ctx;
1468 enum event_type_t event_type;
1470 lockdep_assert_held(&ctx->lock);
1473 * It's 'group type', really, because if our group leader is
1474 * pinned, so are we.
1476 if (event->group_leader != event)
1477 event = event->group_leader;
1479 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1481 event_type |= EVENT_CPU;
1487 * Helper function to initialize event group nodes.
1489 static void init_event_group(struct perf_event *event)
1491 RB_CLEAR_NODE(&event->group_node);
1492 event->group_index = 0;
1496 * Extract pinned or flexible groups from the context
1497 * based on event attrs bits.
1499 static struct perf_event_groups *
1500 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1502 if (event->attr.pinned)
1503 return &ctx->pinned_groups;
1505 return &ctx->flexible_groups;
1509 * Helper function to initializes perf_event_group trees.
1511 static void perf_event_groups_init(struct perf_event_groups *groups)
1513 groups->tree = RB_ROOT;
1518 * Compare function for event groups;
1520 * Implements complex key that first sorts by CPU and then by virtual index
1521 * which provides ordering when rotating groups for the same CPU.
1524 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1526 if (left->cpu < right->cpu)
1528 if (left->cpu > right->cpu)
1531 if (left->group_index < right->group_index)
1533 if (left->group_index > right->group_index)
1540 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1541 * key (see perf_event_groups_less). This places it last inside the CPU
1545 perf_event_groups_insert(struct perf_event_groups *groups,
1546 struct perf_event *event)
1548 struct perf_event *node_event;
1549 struct rb_node *parent;
1550 struct rb_node **node;
1552 event->group_index = ++groups->index;
1554 node = &groups->tree.rb_node;
1559 node_event = container_of(*node, struct perf_event, group_node);
1561 if (perf_event_groups_less(event, node_event))
1562 node = &parent->rb_left;
1564 node = &parent->rb_right;
1567 rb_link_node(&event->group_node, parent, node);
1568 rb_insert_color(&event->group_node, &groups->tree);
1572 * Helper function to insert event into the pinned or flexible groups.
1575 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1577 struct perf_event_groups *groups;
1579 groups = get_event_groups(event, ctx);
1580 perf_event_groups_insert(groups, event);
1584 * Delete a group from a tree.
1587 perf_event_groups_delete(struct perf_event_groups *groups,
1588 struct perf_event *event)
1590 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1591 RB_EMPTY_ROOT(&groups->tree));
1593 rb_erase(&event->group_node, &groups->tree);
1594 init_event_group(event);
1598 * Helper function to delete event from its groups.
1601 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1603 struct perf_event_groups *groups;
1605 groups = get_event_groups(event, ctx);
1606 perf_event_groups_delete(groups, event);
1610 * Get the leftmost event in the @cpu subtree.
1612 static struct perf_event *
1613 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1615 struct perf_event *node_event = NULL, *match = NULL;
1616 struct rb_node *node = groups->tree.rb_node;
1619 node_event = container_of(node, struct perf_event, group_node);
1621 if (cpu < node_event->cpu) {
1622 node = node->rb_left;
1623 } else if (cpu > node_event->cpu) {
1624 node = node->rb_right;
1627 node = node->rb_left;
1635 * Like rb_entry_next_safe() for the @cpu subtree.
1637 static struct perf_event *
1638 perf_event_groups_next(struct perf_event *event)
1640 struct perf_event *next;
1642 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1643 if (next && next->cpu == event->cpu)
1650 * Iterate through the whole groups tree.
1652 #define perf_event_groups_for_each(event, groups) \
1653 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1654 typeof(*event), group_node); event; \
1655 event = rb_entry_safe(rb_next(&event->group_node), \
1656 typeof(*event), group_node))
1659 * Add an event from the lists for its context.
1660 * Must be called with ctx->mutex and ctx->lock held.
1663 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1665 lockdep_assert_held(&ctx->lock);
1667 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1668 event->attach_state |= PERF_ATTACH_CONTEXT;
1670 event->tstamp = perf_event_time(event);
1673 * If we're a stand alone event or group leader, we go to the context
1674 * list, group events are kept attached to the group so that
1675 * perf_group_detach can, at all times, locate all siblings.
1677 if (event->group_leader == event) {
1678 event->group_caps = event->event_caps;
1679 add_event_to_groups(event, ctx);
1682 list_update_cgroup_event(event, ctx, true);
1684 list_add_rcu(&event->event_entry, &ctx->event_list);
1686 if (event->attr.inherit_stat)
1693 * Initialize event state based on the perf_event_attr::disabled.
1695 static inline void perf_event__state_init(struct perf_event *event)
1697 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1698 PERF_EVENT_STATE_INACTIVE;
1701 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1703 int entry = sizeof(u64); /* value */
1707 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1708 size += sizeof(u64);
1710 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1711 size += sizeof(u64);
1713 if (event->attr.read_format & PERF_FORMAT_ID)
1714 entry += sizeof(u64);
1716 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1718 size += sizeof(u64);
1722 event->read_size = size;
1725 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1727 struct perf_sample_data *data;
1730 if (sample_type & PERF_SAMPLE_IP)
1731 size += sizeof(data->ip);
1733 if (sample_type & PERF_SAMPLE_ADDR)
1734 size += sizeof(data->addr);
1736 if (sample_type & PERF_SAMPLE_PERIOD)
1737 size += sizeof(data->period);
1739 if (sample_type & PERF_SAMPLE_WEIGHT)
1740 size += sizeof(data->weight);
1742 if (sample_type & PERF_SAMPLE_READ)
1743 size += event->read_size;
1745 if (sample_type & PERF_SAMPLE_DATA_SRC)
1746 size += sizeof(data->data_src.val);
1748 if (sample_type & PERF_SAMPLE_TRANSACTION)
1749 size += sizeof(data->txn);
1751 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1752 size += sizeof(data->phys_addr);
1754 event->header_size = size;
1758 * Called at perf_event creation and when events are attached/detached from a
1761 static void perf_event__header_size(struct perf_event *event)
1763 __perf_event_read_size(event,
1764 event->group_leader->nr_siblings);
1765 __perf_event_header_size(event, event->attr.sample_type);
1768 static void perf_event__id_header_size(struct perf_event *event)
1770 struct perf_sample_data *data;
1771 u64 sample_type = event->attr.sample_type;
1774 if (sample_type & PERF_SAMPLE_TID)
1775 size += sizeof(data->tid_entry);
1777 if (sample_type & PERF_SAMPLE_TIME)
1778 size += sizeof(data->time);
1780 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1781 size += sizeof(data->id);
1783 if (sample_type & PERF_SAMPLE_ID)
1784 size += sizeof(data->id);
1786 if (sample_type & PERF_SAMPLE_STREAM_ID)
1787 size += sizeof(data->stream_id);
1789 if (sample_type & PERF_SAMPLE_CPU)
1790 size += sizeof(data->cpu_entry);
1792 event->id_header_size = size;
1795 static bool perf_event_validate_size(struct perf_event *event)
1798 * The values computed here will be over-written when we actually
1801 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1802 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1803 perf_event__id_header_size(event);
1806 * Sum the lot; should not exceed the 64k limit we have on records.
1807 * Conservative limit to allow for callchains and other variable fields.
1809 if (event->read_size + event->header_size +
1810 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1816 static void perf_group_attach(struct perf_event *event)
1818 struct perf_event *group_leader = event->group_leader, *pos;
1820 lockdep_assert_held(&event->ctx->lock);
1823 * We can have double attach due to group movement in perf_event_open.
1825 if (event->attach_state & PERF_ATTACH_GROUP)
1828 event->attach_state |= PERF_ATTACH_GROUP;
1830 if (group_leader == event)
1833 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1835 group_leader->group_caps &= event->event_caps;
1837 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1838 group_leader->nr_siblings++;
1840 perf_event__header_size(group_leader);
1842 for_each_sibling_event(pos, group_leader)
1843 perf_event__header_size(pos);
1847 * Remove an event from the lists for its context.
1848 * Must be called with ctx->mutex and ctx->lock held.
1851 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1853 WARN_ON_ONCE(event->ctx != ctx);
1854 lockdep_assert_held(&ctx->lock);
1857 * We can have double detach due to exit/hot-unplug + close.
1859 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1862 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1864 list_update_cgroup_event(event, ctx, false);
1867 if (event->attr.inherit_stat)
1870 list_del_rcu(&event->event_entry);
1872 if (event->group_leader == event)
1873 del_event_from_groups(event, ctx);
1876 * If event was in error state, then keep it
1877 * that way, otherwise bogus counts will be
1878 * returned on read(). The only way to get out
1879 * of error state is by explicit re-enabling
1882 if (event->state > PERF_EVENT_STATE_OFF)
1883 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1888 static void perf_group_detach(struct perf_event *event)
1890 struct perf_event *sibling, *tmp;
1891 struct perf_event_context *ctx = event->ctx;
1893 lockdep_assert_held(&ctx->lock);
1896 * We can have double detach due to exit/hot-unplug + close.
1898 if (!(event->attach_state & PERF_ATTACH_GROUP))
1901 event->attach_state &= ~PERF_ATTACH_GROUP;
1904 * If this is a sibling, remove it from its group.
1906 if (event->group_leader != event) {
1907 list_del_init(&event->sibling_list);
1908 event->group_leader->nr_siblings--;
1913 * If this was a group event with sibling events then
1914 * upgrade the siblings to singleton events by adding them
1915 * to whatever list we are on.
1917 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1919 sibling->group_leader = sibling;
1920 list_del_init(&sibling->sibling_list);
1922 /* Inherit group flags from the previous leader */
1923 sibling->group_caps = event->group_caps;
1925 if (!RB_EMPTY_NODE(&event->group_node)) {
1926 add_event_to_groups(sibling, event->ctx);
1928 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1929 struct list_head *list = sibling->attr.pinned ?
1930 &ctx->pinned_active : &ctx->flexible_active;
1932 list_add_tail(&sibling->active_list, list);
1936 WARN_ON_ONCE(sibling->ctx != event->ctx);
1940 perf_event__header_size(event->group_leader);
1942 for_each_sibling_event(tmp, event->group_leader)
1943 perf_event__header_size(tmp);
1946 static bool is_orphaned_event(struct perf_event *event)
1948 return event->state == PERF_EVENT_STATE_DEAD;
1951 static inline int __pmu_filter_match(struct perf_event *event)
1953 struct pmu *pmu = event->pmu;
1954 return pmu->filter_match ? pmu->filter_match(event) : 1;
1958 * Check whether we should attempt to schedule an event group based on
1959 * PMU-specific filtering. An event group can consist of HW and SW events,
1960 * potentially with a SW leader, so we must check all the filters, to
1961 * determine whether a group is schedulable:
1963 static inline int pmu_filter_match(struct perf_event *event)
1965 struct perf_event *sibling;
1967 if (!__pmu_filter_match(event))
1970 for_each_sibling_event(sibling, event) {
1971 if (!__pmu_filter_match(sibling))
1979 event_filter_match(struct perf_event *event)
1981 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1982 perf_cgroup_match(event) && pmu_filter_match(event);
1986 event_sched_out(struct perf_event *event,
1987 struct perf_cpu_context *cpuctx,
1988 struct perf_event_context *ctx)
1990 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1992 WARN_ON_ONCE(event->ctx != ctx);
1993 lockdep_assert_held(&ctx->lock);
1995 if (event->state != PERF_EVENT_STATE_ACTIVE)
1999 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2000 * we can schedule events _OUT_ individually through things like
2001 * __perf_remove_from_context().
2003 list_del_init(&event->active_list);
2005 perf_pmu_disable(event->pmu);
2007 event->pmu->del(event, 0);
2010 if (READ_ONCE(event->pending_disable) >= 0) {
2011 WRITE_ONCE(event->pending_disable, -1);
2012 state = PERF_EVENT_STATE_OFF;
2014 perf_event_set_state(event, state);
2016 if (!is_software_event(event))
2017 cpuctx->active_oncpu--;
2018 if (!--ctx->nr_active)
2019 perf_event_ctx_deactivate(ctx);
2020 if (event->attr.freq && event->attr.sample_freq)
2022 if (event->attr.exclusive || !cpuctx->active_oncpu)
2023 cpuctx->exclusive = 0;
2025 perf_pmu_enable(event->pmu);
2029 group_sched_out(struct perf_event *group_event,
2030 struct perf_cpu_context *cpuctx,
2031 struct perf_event_context *ctx)
2033 struct perf_event *event;
2035 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2038 perf_pmu_disable(ctx->pmu);
2040 event_sched_out(group_event, cpuctx, ctx);
2043 * Schedule out siblings (if any):
2045 for_each_sibling_event(event, group_event)
2046 event_sched_out(event, cpuctx, ctx);
2048 perf_pmu_enable(ctx->pmu);
2050 if (group_event->attr.exclusive)
2051 cpuctx->exclusive = 0;
2054 #define DETACH_GROUP 0x01UL
2057 * Cross CPU call to remove a performance event
2059 * We disable the event on the hardware level first. After that we
2060 * remove it from the context list.
2063 __perf_remove_from_context(struct perf_event *event,
2064 struct perf_cpu_context *cpuctx,
2065 struct perf_event_context *ctx,
2068 unsigned long flags = (unsigned long)info;
2070 if (ctx->is_active & EVENT_TIME) {
2071 update_context_time(ctx);
2072 update_cgrp_time_from_cpuctx(cpuctx);
2075 event_sched_out(event, cpuctx, ctx);
2076 if (flags & DETACH_GROUP)
2077 perf_group_detach(event);
2078 list_del_event(event, ctx);
2080 if (!ctx->nr_events && ctx->is_active) {
2083 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2084 cpuctx->task_ctx = NULL;
2090 * Remove the event from a task's (or a CPU's) list of events.
2092 * If event->ctx is a cloned context, callers must make sure that
2093 * every task struct that event->ctx->task could possibly point to
2094 * remains valid. This is OK when called from perf_release since
2095 * that only calls us on the top-level context, which can't be a clone.
2096 * When called from perf_event_exit_task, it's OK because the
2097 * context has been detached from its task.
2099 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2101 struct perf_event_context *ctx = event->ctx;
2103 lockdep_assert_held(&ctx->mutex);
2105 event_function_call(event, __perf_remove_from_context, (void *)flags);
2108 * The above event_function_call() can NO-OP when it hits
2109 * TASK_TOMBSTONE. In that case we must already have been detached
2110 * from the context (by perf_event_exit_event()) but the grouping
2111 * might still be in-tact.
2113 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2114 if ((flags & DETACH_GROUP) &&
2115 (event->attach_state & PERF_ATTACH_GROUP)) {
2117 * Since in that case we cannot possibly be scheduled, simply
2120 raw_spin_lock_irq(&ctx->lock);
2121 perf_group_detach(event);
2122 raw_spin_unlock_irq(&ctx->lock);
2127 * Cross CPU call to disable a performance event
2129 static void __perf_event_disable(struct perf_event *event,
2130 struct perf_cpu_context *cpuctx,
2131 struct perf_event_context *ctx,
2134 if (event->state < PERF_EVENT_STATE_INACTIVE)
2137 if (ctx->is_active & EVENT_TIME) {
2138 update_context_time(ctx);
2139 update_cgrp_time_from_event(event);
2142 if (event == event->group_leader)
2143 group_sched_out(event, cpuctx, ctx);
2145 event_sched_out(event, cpuctx, ctx);
2147 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2153 * If event->ctx is a cloned context, callers must make sure that
2154 * every task struct that event->ctx->task could possibly point to
2155 * remains valid. This condition is satisifed when called through
2156 * perf_event_for_each_child or perf_event_for_each because they
2157 * hold the top-level event's child_mutex, so any descendant that
2158 * goes to exit will block in perf_event_exit_event().
2160 * When called from perf_pending_event it's OK because event->ctx
2161 * is the current context on this CPU and preemption is disabled,
2162 * hence we can't get into perf_event_task_sched_out for this context.
2164 static void _perf_event_disable(struct perf_event *event)
2166 struct perf_event_context *ctx = event->ctx;
2168 raw_spin_lock_irq(&ctx->lock);
2169 if (event->state <= PERF_EVENT_STATE_OFF) {
2170 raw_spin_unlock_irq(&ctx->lock);
2173 raw_spin_unlock_irq(&ctx->lock);
2175 event_function_call(event, __perf_event_disable, NULL);
2178 void perf_event_disable_local(struct perf_event *event)
2180 event_function_local(event, __perf_event_disable, NULL);
2184 * Strictly speaking kernel users cannot create groups and therefore this
2185 * interface does not need the perf_event_ctx_lock() magic.
2187 void perf_event_disable(struct perf_event *event)
2189 struct perf_event_context *ctx;
2191 ctx = perf_event_ctx_lock(event);
2192 _perf_event_disable(event);
2193 perf_event_ctx_unlock(event, ctx);
2195 EXPORT_SYMBOL_GPL(perf_event_disable);
2197 void perf_event_disable_inatomic(struct perf_event *event)
2199 WRITE_ONCE(event->pending_disable, smp_processor_id());
2200 /* can fail, see perf_pending_event_disable() */
2201 irq_work_queue(&event->pending);
2204 static void perf_set_shadow_time(struct perf_event *event,
2205 struct perf_event_context *ctx)
2208 * use the correct time source for the time snapshot
2210 * We could get by without this by leveraging the
2211 * fact that to get to this function, the caller
2212 * has most likely already called update_context_time()
2213 * and update_cgrp_time_xx() and thus both timestamp
2214 * are identical (or very close). Given that tstamp is,
2215 * already adjusted for cgroup, we could say that:
2216 * tstamp - ctx->timestamp
2218 * tstamp - cgrp->timestamp.
2220 * Then, in perf_output_read(), the calculation would
2221 * work with no changes because:
2222 * - event is guaranteed scheduled in
2223 * - no scheduled out in between
2224 * - thus the timestamp would be the same
2226 * But this is a bit hairy.
2228 * So instead, we have an explicit cgroup call to remain
2229 * within the time time source all along. We believe it
2230 * is cleaner and simpler to understand.
2232 if (is_cgroup_event(event))
2233 perf_cgroup_set_shadow_time(event, event->tstamp);
2235 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2238 #define MAX_INTERRUPTS (~0ULL)
2240 static void perf_log_throttle(struct perf_event *event, int enable);
2241 static void perf_log_itrace_start(struct perf_event *event);
2244 event_sched_in(struct perf_event *event,
2245 struct perf_cpu_context *cpuctx,
2246 struct perf_event_context *ctx)
2250 lockdep_assert_held(&ctx->lock);
2252 if (event->state <= PERF_EVENT_STATE_OFF)
2255 WRITE_ONCE(event->oncpu, smp_processor_id());
2257 * Order event::oncpu write to happen before the ACTIVE state is
2258 * visible. This allows perf_event_{stop,read}() to observe the correct
2259 * ->oncpu if it sees ACTIVE.
2262 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2265 * Unthrottle events, since we scheduled we might have missed several
2266 * ticks already, also for a heavily scheduling task there is little
2267 * guarantee it'll get a tick in a timely manner.
2269 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2270 perf_log_throttle(event, 1);
2271 event->hw.interrupts = 0;
2274 perf_pmu_disable(event->pmu);
2276 perf_set_shadow_time(event, ctx);
2278 perf_log_itrace_start(event);
2280 if (event->pmu->add(event, PERF_EF_START)) {
2281 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2287 if (!is_software_event(event))
2288 cpuctx->active_oncpu++;
2289 if (!ctx->nr_active++)
2290 perf_event_ctx_activate(ctx);
2291 if (event->attr.freq && event->attr.sample_freq)
2294 if (event->attr.exclusive)
2295 cpuctx->exclusive = 1;
2298 perf_pmu_enable(event->pmu);
2304 group_sched_in(struct perf_event *group_event,
2305 struct perf_cpu_context *cpuctx,
2306 struct perf_event_context *ctx)
2308 struct perf_event *event, *partial_group = NULL;
2309 struct pmu *pmu = ctx->pmu;
2311 if (group_event->state == PERF_EVENT_STATE_OFF)
2314 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2316 if (event_sched_in(group_event, cpuctx, ctx)) {
2317 pmu->cancel_txn(pmu);
2318 perf_mux_hrtimer_restart(cpuctx);
2323 * Schedule in siblings as one group (if any):
2325 for_each_sibling_event(event, group_event) {
2326 if (event_sched_in(event, cpuctx, ctx)) {
2327 partial_group = event;
2332 if (!pmu->commit_txn(pmu))
2337 * Groups can be scheduled in as one unit only, so undo any
2338 * partial group before returning:
2339 * The events up to the failed event are scheduled out normally.
2341 for_each_sibling_event(event, group_event) {
2342 if (event == partial_group)
2345 event_sched_out(event, cpuctx, ctx);
2347 event_sched_out(group_event, cpuctx, ctx);
2349 pmu->cancel_txn(pmu);
2351 perf_mux_hrtimer_restart(cpuctx);
2357 * Work out whether we can put this event group on the CPU now.
2359 static int group_can_go_on(struct perf_event *event,
2360 struct perf_cpu_context *cpuctx,
2364 * Groups consisting entirely of software events can always go on.
2366 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2369 * If an exclusive group is already on, no other hardware
2372 if (cpuctx->exclusive)
2375 * If this group is exclusive and there are already
2376 * events on the CPU, it can't go on.
2378 if (event->attr.exclusive && cpuctx->active_oncpu)
2381 * Otherwise, try to add it if all previous groups were able
2387 static void add_event_to_ctx(struct perf_event *event,
2388 struct perf_event_context *ctx)
2390 list_add_event(event, ctx);
2391 perf_group_attach(event);
2394 static void ctx_sched_out(struct perf_event_context *ctx,
2395 struct perf_cpu_context *cpuctx,
2396 enum event_type_t event_type);
2398 ctx_sched_in(struct perf_event_context *ctx,
2399 struct perf_cpu_context *cpuctx,
2400 enum event_type_t event_type,
2401 struct task_struct *task);
2403 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2404 struct perf_event_context *ctx,
2405 enum event_type_t event_type)
2407 if (!cpuctx->task_ctx)
2410 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2413 ctx_sched_out(ctx, cpuctx, event_type);
2416 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2417 struct perf_event_context *ctx,
2418 struct task_struct *task)
2420 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2422 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2423 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2425 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2429 * We want to maintain the following priority of scheduling:
2430 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2431 * - task pinned (EVENT_PINNED)
2432 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2433 * - task flexible (EVENT_FLEXIBLE).
2435 * In order to avoid unscheduling and scheduling back in everything every
2436 * time an event is added, only do it for the groups of equal priority and
2439 * This can be called after a batch operation on task events, in which case
2440 * event_type is a bit mask of the types of events involved. For CPU events,
2441 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2443 static void ctx_resched(struct perf_cpu_context *cpuctx,
2444 struct perf_event_context *task_ctx,
2445 enum event_type_t event_type)
2447 enum event_type_t ctx_event_type;
2448 bool cpu_event = !!(event_type & EVENT_CPU);
2451 * If pinned groups are involved, flexible groups also need to be
2454 if (event_type & EVENT_PINNED)
2455 event_type |= EVENT_FLEXIBLE;
2457 ctx_event_type = event_type & EVENT_ALL;
2459 perf_pmu_disable(cpuctx->ctx.pmu);
2461 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2464 * Decide which cpu ctx groups to schedule out based on the types
2465 * of events that caused rescheduling:
2466 * - EVENT_CPU: schedule out corresponding groups;
2467 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2468 * - otherwise, do nothing more.
2471 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2472 else if (ctx_event_type & EVENT_PINNED)
2473 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2475 perf_event_sched_in(cpuctx, task_ctx, current);
2476 perf_pmu_enable(cpuctx->ctx.pmu);
2480 * Cross CPU call to install and enable a performance event
2482 * Very similar to remote_function() + event_function() but cannot assume that
2483 * things like ctx->is_active and cpuctx->task_ctx are set.
2485 static int __perf_install_in_context(void *info)
2487 struct perf_event *event = info;
2488 struct perf_event_context *ctx = event->ctx;
2489 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2490 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2491 bool reprogram = true;
2494 raw_spin_lock(&cpuctx->ctx.lock);
2496 raw_spin_lock(&ctx->lock);
2499 reprogram = (ctx->task == current);
2502 * If the task is running, it must be running on this CPU,
2503 * otherwise we cannot reprogram things.
2505 * If its not running, we don't care, ctx->lock will
2506 * serialize against it becoming runnable.
2508 if (task_curr(ctx->task) && !reprogram) {
2513 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2514 } else if (task_ctx) {
2515 raw_spin_lock(&task_ctx->lock);
2518 #ifdef CONFIG_CGROUP_PERF
2519 if (is_cgroup_event(event)) {
2521 * If the current cgroup doesn't match the event's
2522 * cgroup, we should not try to schedule it.
2524 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2525 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2526 event->cgrp->css.cgroup);
2531 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2532 add_event_to_ctx(event, ctx);
2533 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2535 add_event_to_ctx(event, ctx);
2539 perf_ctx_unlock(cpuctx, task_ctx);
2544 static bool exclusive_event_installable(struct perf_event *event,
2545 struct perf_event_context *ctx);
2548 * Attach a performance event to a context.
2550 * Very similar to event_function_call, see comment there.
2553 perf_install_in_context(struct perf_event_context *ctx,
2554 struct perf_event *event,
2557 struct task_struct *task = READ_ONCE(ctx->task);
2559 lockdep_assert_held(&ctx->mutex);
2561 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2563 if (event->cpu != -1)
2567 * Ensures that if we can observe event->ctx, both the event and ctx
2568 * will be 'complete'. See perf_iterate_sb_cpu().
2570 smp_store_release(&event->ctx, ctx);
2573 cpu_function_call(cpu, __perf_install_in_context, event);
2578 * Should not happen, we validate the ctx is still alive before calling.
2580 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2584 * Installing events is tricky because we cannot rely on ctx->is_active
2585 * to be set in case this is the nr_events 0 -> 1 transition.
2587 * Instead we use task_curr(), which tells us if the task is running.
2588 * However, since we use task_curr() outside of rq::lock, we can race
2589 * against the actual state. This means the result can be wrong.
2591 * If we get a false positive, we retry, this is harmless.
2593 * If we get a false negative, things are complicated. If we are after
2594 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2595 * value must be correct. If we're before, it doesn't matter since
2596 * perf_event_context_sched_in() will program the counter.
2598 * However, this hinges on the remote context switch having observed
2599 * our task->perf_event_ctxp[] store, such that it will in fact take
2600 * ctx::lock in perf_event_context_sched_in().
2602 * We do this by task_function_call(), if the IPI fails to hit the task
2603 * we know any future context switch of task must see the
2604 * perf_event_ctpx[] store.
2608 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2609 * task_cpu() load, such that if the IPI then does not find the task
2610 * running, a future context switch of that task must observe the
2615 if (!task_function_call(task, __perf_install_in_context, event))
2618 raw_spin_lock_irq(&ctx->lock);
2620 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2622 * Cannot happen because we already checked above (which also
2623 * cannot happen), and we hold ctx->mutex, which serializes us
2624 * against perf_event_exit_task_context().
2626 raw_spin_unlock_irq(&ctx->lock);
2630 * If the task is not running, ctx->lock will avoid it becoming so,
2631 * thus we can safely install the event.
2633 if (task_curr(task)) {
2634 raw_spin_unlock_irq(&ctx->lock);
2637 add_event_to_ctx(event, ctx);
2638 raw_spin_unlock_irq(&ctx->lock);
2642 * Cross CPU call to enable a performance event
2644 static void __perf_event_enable(struct perf_event *event,
2645 struct perf_cpu_context *cpuctx,
2646 struct perf_event_context *ctx,
2649 struct perf_event *leader = event->group_leader;
2650 struct perf_event_context *task_ctx;
2652 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2653 event->state <= PERF_EVENT_STATE_ERROR)
2657 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2659 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2661 if (!ctx->is_active)
2664 if (!event_filter_match(event)) {
2665 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2670 * If the event is in a group and isn't the group leader,
2671 * then don't put it on unless the group is on.
2673 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2674 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2678 task_ctx = cpuctx->task_ctx;
2680 WARN_ON_ONCE(task_ctx != ctx);
2682 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2688 * If event->ctx is a cloned context, callers must make sure that
2689 * every task struct that event->ctx->task could possibly point to
2690 * remains valid. This condition is satisfied when called through
2691 * perf_event_for_each_child or perf_event_for_each as described
2692 * for perf_event_disable.
2694 static void _perf_event_enable(struct perf_event *event)
2696 struct perf_event_context *ctx = event->ctx;
2698 raw_spin_lock_irq(&ctx->lock);
2699 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2700 event->state < PERF_EVENT_STATE_ERROR) {
2701 raw_spin_unlock_irq(&ctx->lock);
2706 * If the event is in error state, clear that first.
2708 * That way, if we see the event in error state below, we know that it
2709 * has gone back into error state, as distinct from the task having
2710 * been scheduled away before the cross-call arrived.
2712 if (event->state == PERF_EVENT_STATE_ERROR)
2713 event->state = PERF_EVENT_STATE_OFF;
2714 raw_spin_unlock_irq(&ctx->lock);
2716 event_function_call(event, __perf_event_enable, NULL);
2720 * See perf_event_disable();
2722 void perf_event_enable(struct perf_event *event)
2724 struct perf_event_context *ctx;
2726 ctx = perf_event_ctx_lock(event);
2727 _perf_event_enable(event);
2728 perf_event_ctx_unlock(event, ctx);
2730 EXPORT_SYMBOL_GPL(perf_event_enable);
2732 struct stop_event_data {
2733 struct perf_event *event;
2734 unsigned int restart;
2737 static int __perf_event_stop(void *info)
2739 struct stop_event_data *sd = info;
2740 struct perf_event *event = sd->event;
2742 /* if it's already INACTIVE, do nothing */
2743 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2746 /* matches smp_wmb() in event_sched_in() */
2750 * There is a window with interrupts enabled before we get here,
2751 * so we need to check again lest we try to stop another CPU's event.
2753 if (READ_ONCE(event->oncpu) != smp_processor_id())
2756 event->pmu->stop(event, PERF_EF_UPDATE);
2759 * May race with the actual stop (through perf_pmu_output_stop()),
2760 * but it is only used for events with AUX ring buffer, and such
2761 * events will refuse to restart because of rb::aux_mmap_count==0,
2762 * see comments in perf_aux_output_begin().
2764 * Since this is happening on an event-local CPU, no trace is lost
2768 event->pmu->start(event, 0);
2773 static int perf_event_stop(struct perf_event *event, int restart)
2775 struct stop_event_data sd = {
2782 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2785 /* matches smp_wmb() in event_sched_in() */
2789 * We only want to restart ACTIVE events, so if the event goes
2790 * inactive here (event->oncpu==-1), there's nothing more to do;
2791 * fall through with ret==-ENXIO.
2793 ret = cpu_function_call(READ_ONCE(event->oncpu),
2794 __perf_event_stop, &sd);
2795 } while (ret == -EAGAIN);
2801 * In order to contain the amount of racy and tricky in the address filter
2802 * configuration management, it is a two part process:
2804 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2805 * we update the addresses of corresponding vmas in
2806 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2807 * (p2) when an event is scheduled in (pmu::add), it calls
2808 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2809 * if the generation has changed since the previous call.
2811 * If (p1) happens while the event is active, we restart it to force (p2).
2813 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2814 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2816 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2817 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2819 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2822 void perf_event_addr_filters_sync(struct perf_event *event)
2824 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2826 if (!has_addr_filter(event))
2829 raw_spin_lock(&ifh->lock);
2830 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2831 event->pmu->addr_filters_sync(event);
2832 event->hw.addr_filters_gen = event->addr_filters_gen;
2834 raw_spin_unlock(&ifh->lock);
2836 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2838 static int _perf_event_refresh(struct perf_event *event, int refresh)
2841 * not supported on inherited events
2843 if (event->attr.inherit || !is_sampling_event(event))
2846 atomic_add(refresh, &event->event_limit);
2847 _perf_event_enable(event);
2853 * See perf_event_disable()
2855 int perf_event_refresh(struct perf_event *event, int refresh)
2857 struct perf_event_context *ctx;
2860 ctx = perf_event_ctx_lock(event);
2861 ret = _perf_event_refresh(event, refresh);
2862 perf_event_ctx_unlock(event, ctx);
2866 EXPORT_SYMBOL_GPL(perf_event_refresh);
2868 static int perf_event_modify_breakpoint(struct perf_event *bp,
2869 struct perf_event_attr *attr)
2873 _perf_event_disable(bp);
2875 err = modify_user_hw_breakpoint_check(bp, attr, true);
2877 if (!bp->attr.disabled)
2878 _perf_event_enable(bp);
2883 static int perf_event_modify_attr(struct perf_event *event,
2884 struct perf_event_attr *attr)
2886 if (event->attr.type != attr->type)
2889 switch (event->attr.type) {
2890 case PERF_TYPE_BREAKPOINT:
2891 return perf_event_modify_breakpoint(event, attr);
2893 /* Place holder for future additions. */
2898 static void ctx_sched_out(struct perf_event_context *ctx,
2899 struct perf_cpu_context *cpuctx,
2900 enum event_type_t event_type)
2902 struct perf_event *event, *tmp;
2903 int is_active = ctx->is_active;
2905 lockdep_assert_held(&ctx->lock);
2907 if (likely(!ctx->nr_events)) {
2909 * See __perf_remove_from_context().
2911 WARN_ON_ONCE(ctx->is_active);
2913 WARN_ON_ONCE(cpuctx->task_ctx);
2917 ctx->is_active &= ~event_type;
2918 if (!(ctx->is_active & EVENT_ALL))
2922 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2923 if (!ctx->is_active)
2924 cpuctx->task_ctx = NULL;
2928 * Always update time if it was set; not only when it changes.
2929 * Otherwise we can 'forget' to update time for any but the last
2930 * context we sched out. For example:
2932 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2933 * ctx_sched_out(.event_type = EVENT_PINNED)
2935 * would only update time for the pinned events.
2937 if (is_active & EVENT_TIME) {
2938 /* update (and stop) ctx time */
2939 update_context_time(ctx);
2940 update_cgrp_time_from_cpuctx(cpuctx);
2943 is_active ^= ctx->is_active; /* changed bits */
2945 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2948 perf_pmu_disable(ctx->pmu);
2949 if (is_active & EVENT_PINNED) {
2950 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2951 group_sched_out(event, cpuctx, ctx);
2954 if (is_active & EVENT_FLEXIBLE) {
2955 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2956 group_sched_out(event, cpuctx, ctx);
2958 perf_pmu_enable(ctx->pmu);
2962 * Test whether two contexts are equivalent, i.e. whether they have both been
2963 * cloned from the same version of the same context.
2965 * Equivalence is measured using a generation number in the context that is
2966 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2967 * and list_del_event().
2969 static int context_equiv(struct perf_event_context *ctx1,
2970 struct perf_event_context *ctx2)
2972 lockdep_assert_held(&ctx1->lock);
2973 lockdep_assert_held(&ctx2->lock);
2975 /* Pinning disables the swap optimization */
2976 if (ctx1->pin_count || ctx2->pin_count)
2979 /* If ctx1 is the parent of ctx2 */
2980 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2983 /* If ctx2 is the parent of ctx1 */
2984 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2988 * If ctx1 and ctx2 have the same parent; we flatten the parent
2989 * hierarchy, see perf_event_init_context().
2991 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2992 ctx1->parent_gen == ctx2->parent_gen)
2999 static void __perf_event_sync_stat(struct perf_event *event,
3000 struct perf_event *next_event)
3004 if (!event->attr.inherit_stat)
3008 * Update the event value, we cannot use perf_event_read()
3009 * because we're in the middle of a context switch and have IRQs
3010 * disabled, which upsets smp_call_function_single(), however
3011 * we know the event must be on the current CPU, therefore we
3012 * don't need to use it.
3014 if (event->state == PERF_EVENT_STATE_ACTIVE)
3015 event->pmu->read(event);
3017 perf_event_update_time(event);
3020 * In order to keep per-task stats reliable we need to flip the event
3021 * values when we flip the contexts.
3023 value = local64_read(&next_event->count);
3024 value = local64_xchg(&event->count, value);
3025 local64_set(&next_event->count, value);
3027 swap(event->total_time_enabled, next_event->total_time_enabled);
3028 swap(event->total_time_running, next_event->total_time_running);
3031 * Since we swizzled the values, update the user visible data too.
3033 perf_event_update_userpage(event);
3034 perf_event_update_userpage(next_event);
3037 static void perf_event_sync_stat(struct perf_event_context *ctx,
3038 struct perf_event_context *next_ctx)
3040 struct perf_event *event, *next_event;
3045 update_context_time(ctx);
3047 event = list_first_entry(&ctx->event_list,
3048 struct perf_event, event_entry);
3050 next_event = list_first_entry(&next_ctx->event_list,
3051 struct perf_event, event_entry);
3053 while (&event->event_entry != &ctx->event_list &&
3054 &next_event->event_entry != &next_ctx->event_list) {
3056 __perf_event_sync_stat(event, next_event);
3058 event = list_next_entry(event, event_entry);
3059 next_event = list_next_entry(next_event, event_entry);
3063 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3064 struct task_struct *next)
3066 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3067 struct perf_event_context *next_ctx;
3068 struct perf_event_context *parent, *next_parent;
3069 struct perf_cpu_context *cpuctx;
3075 cpuctx = __get_cpu_context(ctx);
3076 if (!cpuctx->task_ctx)
3080 next_ctx = next->perf_event_ctxp[ctxn];
3084 parent = rcu_dereference(ctx->parent_ctx);
3085 next_parent = rcu_dereference(next_ctx->parent_ctx);
3087 /* If neither context have a parent context; they cannot be clones. */
3088 if (!parent && !next_parent)
3091 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3093 * Looks like the two contexts are clones, so we might be
3094 * able to optimize the context switch. We lock both
3095 * contexts and check that they are clones under the
3096 * lock (including re-checking that neither has been
3097 * uncloned in the meantime). It doesn't matter which
3098 * order we take the locks because no other cpu could
3099 * be trying to lock both of these tasks.
3101 raw_spin_lock(&ctx->lock);
3102 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3103 if (context_equiv(ctx, next_ctx)) {
3104 WRITE_ONCE(ctx->task, next);
3105 WRITE_ONCE(next_ctx->task, task);
3107 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3110 * RCU_INIT_POINTER here is safe because we've not
3111 * modified the ctx and the above modification of
3112 * ctx->task and ctx->task_ctx_data are immaterial
3113 * since those values are always verified under
3114 * ctx->lock which we're now holding.
3116 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3117 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3121 perf_event_sync_stat(ctx, next_ctx);
3123 raw_spin_unlock(&next_ctx->lock);
3124 raw_spin_unlock(&ctx->lock);
3130 raw_spin_lock(&ctx->lock);
3131 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3132 raw_spin_unlock(&ctx->lock);
3136 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3138 void perf_sched_cb_dec(struct pmu *pmu)
3140 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3142 this_cpu_dec(perf_sched_cb_usages);
3144 if (!--cpuctx->sched_cb_usage)
3145 list_del(&cpuctx->sched_cb_entry);
3149 void perf_sched_cb_inc(struct pmu *pmu)
3151 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3153 if (!cpuctx->sched_cb_usage++)
3154 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3156 this_cpu_inc(perf_sched_cb_usages);
3160 * This function provides the context switch callback to the lower code
3161 * layer. It is invoked ONLY when the context switch callback is enabled.
3163 * This callback is relevant even to per-cpu events; for example multi event
3164 * PEBS requires this to provide PID/TID information. This requires we flush
3165 * all queued PEBS records before we context switch to a new task.
3167 static void perf_pmu_sched_task(struct task_struct *prev,
3168 struct task_struct *next,
3171 struct perf_cpu_context *cpuctx;
3177 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3178 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3180 if (WARN_ON_ONCE(!pmu->sched_task))
3183 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3184 perf_pmu_disable(pmu);
3186 pmu->sched_task(cpuctx->task_ctx, sched_in);
3188 perf_pmu_enable(pmu);
3189 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3193 static void perf_event_switch(struct task_struct *task,
3194 struct task_struct *next_prev, bool sched_in);
3196 #define for_each_task_context_nr(ctxn) \
3197 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3200 * Called from scheduler to remove the events of the current task,
3201 * with interrupts disabled.
3203 * We stop each event and update the event value in event->count.
3205 * This does not protect us against NMI, but disable()
3206 * sets the disabled bit in the control field of event _before_
3207 * accessing the event control register. If a NMI hits, then it will
3208 * not restart the event.
3210 void __perf_event_task_sched_out(struct task_struct *task,
3211 struct task_struct *next)
3215 if (__this_cpu_read(perf_sched_cb_usages))
3216 perf_pmu_sched_task(task, next, false);
3218 if (atomic_read(&nr_switch_events))
3219 perf_event_switch(task, next, false);
3221 for_each_task_context_nr(ctxn)
3222 perf_event_context_sched_out(task, ctxn, next);
3225 * if cgroup events exist on this CPU, then we need
3226 * to check if we have to switch out PMU state.
3227 * cgroup event are system-wide mode only
3229 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3230 perf_cgroup_sched_out(task, next);
3234 * Called with IRQs disabled
3236 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3237 enum event_type_t event_type)
3239 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3242 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3243 int (*func)(struct perf_event *, void *), void *data)
3245 struct perf_event **evt, *evt1, *evt2;
3248 evt1 = perf_event_groups_first(groups, -1);
3249 evt2 = perf_event_groups_first(groups, cpu);
3251 while (evt1 || evt2) {
3253 if (evt1->group_index < evt2->group_index)
3263 ret = func(*evt, data);
3267 *evt = perf_event_groups_next(*evt);
3273 struct sched_in_data {
3274 struct perf_event_context *ctx;
3275 struct perf_cpu_context *cpuctx;
3279 static int pinned_sched_in(struct perf_event *event, void *data)
3281 struct sched_in_data *sid = data;
3283 if (event->state <= PERF_EVENT_STATE_OFF)
3286 if (!event_filter_match(event))
3289 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3290 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3291 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3295 * If this pinned group hasn't been scheduled,
3296 * put it in error state.
3298 if (event->state == PERF_EVENT_STATE_INACTIVE)
3299 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3304 static int flexible_sched_in(struct perf_event *event, void *data)
3306 struct sched_in_data *sid = data;
3308 if (event->state <= PERF_EVENT_STATE_OFF)
3311 if (!event_filter_match(event))
3314 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3315 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3316 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3318 sid->can_add_hw = 0;
3325 ctx_pinned_sched_in(struct perf_event_context *ctx,
3326 struct perf_cpu_context *cpuctx)
3328 struct sched_in_data sid = {
3334 visit_groups_merge(&ctx->pinned_groups,
3336 pinned_sched_in, &sid);
3340 ctx_flexible_sched_in(struct perf_event_context *ctx,
3341 struct perf_cpu_context *cpuctx)
3343 struct sched_in_data sid = {
3349 visit_groups_merge(&ctx->flexible_groups,
3351 flexible_sched_in, &sid);
3355 ctx_sched_in(struct perf_event_context *ctx,
3356 struct perf_cpu_context *cpuctx,
3357 enum event_type_t event_type,
3358 struct task_struct *task)
3360 int is_active = ctx->is_active;
3363 lockdep_assert_held(&ctx->lock);
3365 if (likely(!ctx->nr_events))
3368 ctx->is_active |= (event_type | EVENT_TIME);
3371 cpuctx->task_ctx = ctx;
3373 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3376 is_active ^= ctx->is_active; /* changed bits */
3378 if (is_active & EVENT_TIME) {
3379 /* start ctx time */
3381 ctx->timestamp = now;
3382 perf_cgroup_set_timestamp(task, ctx);
3386 * First go through the list and put on any pinned groups
3387 * in order to give them the best chance of going on.
3389 if (is_active & EVENT_PINNED)
3390 ctx_pinned_sched_in(ctx, cpuctx);
3392 /* Then walk through the lower prio flexible groups */
3393 if (is_active & EVENT_FLEXIBLE)
3394 ctx_flexible_sched_in(ctx, cpuctx);
3397 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3398 enum event_type_t event_type,
3399 struct task_struct *task)
3401 struct perf_event_context *ctx = &cpuctx->ctx;
3403 ctx_sched_in(ctx, cpuctx, event_type, task);
3406 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3407 struct task_struct *task)
3409 struct perf_cpu_context *cpuctx;
3411 cpuctx = __get_cpu_context(ctx);
3412 if (cpuctx->task_ctx == ctx)
3415 perf_ctx_lock(cpuctx, ctx);
3417 * We must check ctx->nr_events while holding ctx->lock, such
3418 * that we serialize against perf_install_in_context().
3420 if (!ctx->nr_events)
3423 perf_pmu_disable(ctx->pmu);
3425 * We want to keep the following priority order:
3426 * cpu pinned (that don't need to move), task pinned,
3427 * cpu flexible, task flexible.
3429 * However, if task's ctx is not carrying any pinned
3430 * events, no need to flip the cpuctx's events around.
3432 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3433 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3434 perf_event_sched_in(cpuctx, ctx, task);
3435 perf_pmu_enable(ctx->pmu);
3438 perf_ctx_unlock(cpuctx, ctx);
3442 * Called from scheduler to add the events of the current task
3443 * with interrupts disabled.
3445 * We restore the event value and then enable it.
3447 * This does not protect us against NMI, but enable()
3448 * sets the enabled bit in the control field of event _before_
3449 * accessing the event control register. If a NMI hits, then it will
3450 * keep the event running.
3452 void __perf_event_task_sched_in(struct task_struct *prev,
3453 struct task_struct *task)
3455 struct perf_event_context *ctx;
3459 * If cgroup events exist on this CPU, then we need to check if we have
3460 * to switch in PMU state; cgroup event are system-wide mode only.
3462 * Since cgroup events are CPU events, we must schedule these in before
3463 * we schedule in the task events.
3465 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3466 perf_cgroup_sched_in(prev, task);
3468 for_each_task_context_nr(ctxn) {
3469 ctx = task->perf_event_ctxp[ctxn];
3473 perf_event_context_sched_in(ctx, task);
3476 if (atomic_read(&nr_switch_events))
3477 perf_event_switch(task, prev, true);
3479 if (__this_cpu_read(perf_sched_cb_usages))
3480 perf_pmu_sched_task(prev, task, true);
3483 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3485 u64 frequency = event->attr.sample_freq;
3486 u64 sec = NSEC_PER_SEC;
3487 u64 divisor, dividend;
3489 int count_fls, nsec_fls, frequency_fls, sec_fls;
3491 count_fls = fls64(count);
3492 nsec_fls = fls64(nsec);
3493 frequency_fls = fls64(frequency);
3497 * We got @count in @nsec, with a target of sample_freq HZ
3498 * the target period becomes:
3501 * period = -------------------
3502 * @nsec * sample_freq
3507 * Reduce accuracy by one bit such that @a and @b converge
3508 * to a similar magnitude.
3510 #define REDUCE_FLS(a, b) \
3512 if (a##_fls > b##_fls) { \
3522 * Reduce accuracy until either term fits in a u64, then proceed with
3523 * the other, so that finally we can do a u64/u64 division.
3525 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3526 REDUCE_FLS(nsec, frequency);
3527 REDUCE_FLS(sec, count);
3530 if (count_fls + sec_fls > 64) {
3531 divisor = nsec * frequency;
3533 while (count_fls + sec_fls > 64) {
3534 REDUCE_FLS(count, sec);
3538 dividend = count * sec;
3540 dividend = count * sec;
3542 while (nsec_fls + frequency_fls > 64) {
3543 REDUCE_FLS(nsec, frequency);
3547 divisor = nsec * frequency;
3553 return div64_u64(dividend, divisor);
3556 static DEFINE_PER_CPU(int, perf_throttled_count);
3557 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3559 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3561 struct hw_perf_event *hwc = &event->hw;
3562 s64 period, sample_period;
3565 period = perf_calculate_period(event, nsec, count);
3567 delta = (s64)(period - hwc->sample_period);
3568 delta = (delta + 7) / 8; /* low pass filter */
3570 sample_period = hwc->sample_period + delta;
3575 hwc->sample_period = sample_period;
3577 if (local64_read(&hwc->period_left) > 8*sample_period) {
3579 event->pmu->stop(event, PERF_EF_UPDATE);
3581 local64_set(&hwc->period_left, 0);
3584 event->pmu->start(event, PERF_EF_RELOAD);
3589 * combine freq adjustment with unthrottling to avoid two passes over the
3590 * events. At the same time, make sure, having freq events does not change
3591 * the rate of unthrottling as that would introduce bias.
3593 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3596 struct perf_event *event;
3597 struct hw_perf_event *hwc;
3598 u64 now, period = TICK_NSEC;
3602 * only need to iterate over all events iff:
3603 * - context have events in frequency mode (needs freq adjust)
3604 * - there are events to unthrottle on this cpu
3606 if (!(ctx->nr_freq || needs_unthr))
3609 raw_spin_lock(&ctx->lock);
3610 perf_pmu_disable(ctx->pmu);
3612 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3613 if (event->state != PERF_EVENT_STATE_ACTIVE)
3616 if (!event_filter_match(event))
3619 perf_pmu_disable(event->pmu);
3623 if (hwc->interrupts == MAX_INTERRUPTS) {
3624 hwc->interrupts = 0;
3625 perf_log_throttle(event, 1);
3626 event->pmu->start(event, 0);
3629 if (!event->attr.freq || !event->attr.sample_freq)
3633 * stop the event and update event->count
3635 event->pmu->stop(event, PERF_EF_UPDATE);
3637 now = local64_read(&event->count);
3638 delta = now - hwc->freq_count_stamp;
3639 hwc->freq_count_stamp = now;
3643 * reload only if value has changed
3644 * we have stopped the event so tell that
3645 * to perf_adjust_period() to avoid stopping it
3649 perf_adjust_period(event, period, delta, false);
3651 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3653 perf_pmu_enable(event->pmu);
3656 perf_pmu_enable(ctx->pmu);
3657 raw_spin_unlock(&ctx->lock);
3661 * Move @event to the tail of the @ctx's elegible events.
3663 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3666 * Rotate the first entry last of non-pinned groups. Rotation might be
3667 * disabled by the inheritance code.
3669 if (ctx->rotate_disable)
3672 perf_event_groups_delete(&ctx->flexible_groups, event);
3673 perf_event_groups_insert(&ctx->flexible_groups, event);
3676 static inline struct perf_event *
3677 ctx_first_active(struct perf_event_context *ctx)
3679 return list_first_entry_or_null(&ctx->flexible_active,
3680 struct perf_event, active_list);
3683 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3685 struct perf_event *cpu_event = NULL, *task_event = NULL;
3686 bool cpu_rotate = false, task_rotate = false;
3687 struct perf_event_context *ctx = NULL;
3690 * Since we run this from IRQ context, nobody can install new
3691 * events, thus the event count values are stable.
3694 if (cpuctx->ctx.nr_events) {
3695 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3699 ctx = cpuctx->task_ctx;
3700 if (ctx && ctx->nr_events) {
3701 if (ctx->nr_events != ctx->nr_active)
3705 if (!(cpu_rotate || task_rotate))
3708 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3709 perf_pmu_disable(cpuctx->ctx.pmu);
3712 task_event = ctx_first_active(ctx);
3714 cpu_event = ctx_first_active(&cpuctx->ctx);
3717 * As per the order given at ctx_resched() first 'pop' task flexible
3718 * and then, if needed CPU flexible.
3720 if (task_event || (ctx && cpu_event))
3721 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3723 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3726 rotate_ctx(ctx, task_event);
3728 rotate_ctx(&cpuctx->ctx, cpu_event);
3730 perf_event_sched_in(cpuctx, ctx, current);
3732 perf_pmu_enable(cpuctx->ctx.pmu);
3733 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3738 void perf_event_task_tick(void)
3740 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3741 struct perf_event_context *ctx, *tmp;
3744 lockdep_assert_irqs_disabled();
3746 __this_cpu_inc(perf_throttled_seq);
3747 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3748 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3750 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3751 perf_adjust_freq_unthr_context(ctx, throttled);
3754 static int event_enable_on_exec(struct perf_event *event,
3755 struct perf_event_context *ctx)
3757 if (!event->attr.enable_on_exec)
3760 event->attr.enable_on_exec = 0;
3761 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3764 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3770 * Enable all of a task's events that have been marked enable-on-exec.
3771 * This expects task == current.
3773 static void perf_event_enable_on_exec(int ctxn)
3775 struct perf_event_context *ctx, *clone_ctx = NULL;
3776 enum event_type_t event_type = 0;
3777 struct perf_cpu_context *cpuctx;
3778 struct perf_event *event;
3779 unsigned long flags;
3782 local_irq_save(flags);
3783 ctx = current->perf_event_ctxp[ctxn];
3784 if (!ctx || !ctx->nr_events)
3787 cpuctx = __get_cpu_context(ctx);
3788 perf_ctx_lock(cpuctx, ctx);
3789 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3790 list_for_each_entry(event, &ctx->event_list, event_entry) {
3791 enabled |= event_enable_on_exec(event, ctx);
3792 event_type |= get_event_type(event);
3796 * Unclone and reschedule this context if we enabled any event.
3799 clone_ctx = unclone_ctx(ctx);
3800 ctx_resched(cpuctx, ctx, event_type);
3802 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3804 perf_ctx_unlock(cpuctx, ctx);
3807 local_irq_restore(flags);
3813 struct perf_read_data {
3814 struct perf_event *event;
3819 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3821 u16 local_pkg, event_pkg;
3823 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3824 int local_cpu = smp_processor_id();
3826 event_pkg = topology_physical_package_id(event_cpu);
3827 local_pkg = topology_physical_package_id(local_cpu);
3829 if (event_pkg == local_pkg)
3837 * Cross CPU call to read the hardware event
3839 static void __perf_event_read(void *info)
3841 struct perf_read_data *data = info;
3842 struct perf_event *sub, *event = data->event;
3843 struct perf_event_context *ctx = event->ctx;
3844 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3845 struct pmu *pmu = event->pmu;
3848 * If this is a task context, we need to check whether it is
3849 * the current task context of this cpu. If not it has been
3850 * scheduled out before the smp call arrived. In that case
3851 * event->count would have been updated to a recent sample
3852 * when the event was scheduled out.
3854 if (ctx->task && cpuctx->task_ctx != ctx)
3857 raw_spin_lock(&ctx->lock);
3858 if (ctx->is_active & EVENT_TIME) {
3859 update_context_time(ctx);
3860 update_cgrp_time_from_event(event);
3863 perf_event_update_time(event);
3865 perf_event_update_sibling_time(event);
3867 if (event->state != PERF_EVENT_STATE_ACTIVE)
3876 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3880 for_each_sibling_event(sub, event) {
3881 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3883 * Use sibling's PMU rather than @event's since
3884 * sibling could be on different (eg: software) PMU.
3886 sub->pmu->read(sub);
3890 data->ret = pmu->commit_txn(pmu);
3893 raw_spin_unlock(&ctx->lock);
3896 static inline u64 perf_event_count(struct perf_event *event)
3898 return local64_read(&event->count) + atomic64_read(&event->child_count);
3902 * NMI-safe method to read a local event, that is an event that
3904 * - either for the current task, or for this CPU
3905 * - does not have inherit set, for inherited task events
3906 * will not be local and we cannot read them atomically
3907 * - must not have a pmu::count method
3909 int perf_event_read_local(struct perf_event *event, u64 *value,
3910 u64 *enabled, u64 *running)
3912 unsigned long flags;
3916 * Disabling interrupts avoids all counter scheduling (context
3917 * switches, timer based rotation and IPIs).
3919 local_irq_save(flags);
3922 * It must not be an event with inherit set, we cannot read
3923 * all child counters from atomic context.
3925 if (event->attr.inherit) {
3930 /* If this is a per-task event, it must be for current */
3931 if ((event->attach_state & PERF_ATTACH_TASK) &&
3932 event->hw.target != current) {
3937 /* If this is a per-CPU event, it must be for this CPU */
3938 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3939 event->cpu != smp_processor_id()) {
3944 /* If this is a pinned event it must be running on this CPU */
3945 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3951 * If the event is currently on this CPU, its either a per-task event,
3952 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3955 if (event->oncpu == smp_processor_id())
3956 event->pmu->read(event);
3958 *value = local64_read(&event->count);
3959 if (enabled || running) {
3960 u64 now = event->shadow_ctx_time + perf_clock();
3961 u64 __enabled, __running;
3963 __perf_update_times(event, now, &__enabled, &__running);
3965 *enabled = __enabled;
3967 *running = __running;
3970 local_irq_restore(flags);
3975 static int perf_event_read(struct perf_event *event, bool group)
3977 enum perf_event_state state = READ_ONCE(event->state);
3978 int event_cpu, ret = 0;
3981 * If event is enabled and currently active on a CPU, update the
3982 * value in the event structure:
3985 if (state == PERF_EVENT_STATE_ACTIVE) {
3986 struct perf_read_data data;
3989 * Orders the ->state and ->oncpu loads such that if we see
3990 * ACTIVE we must also see the right ->oncpu.
3992 * Matches the smp_wmb() from event_sched_in().
3996 event_cpu = READ_ONCE(event->oncpu);
3997 if ((unsigned)event_cpu >= nr_cpu_ids)
4000 data = (struct perf_read_data){
4007 event_cpu = __perf_event_read_cpu(event, event_cpu);
4010 * Purposely ignore the smp_call_function_single() return
4013 * If event_cpu isn't a valid CPU it means the event got
4014 * scheduled out and that will have updated the event count.
4016 * Therefore, either way, we'll have an up-to-date event count
4019 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4023 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4024 struct perf_event_context *ctx = event->ctx;
4025 unsigned long flags;
4027 raw_spin_lock_irqsave(&ctx->lock, flags);
4028 state = event->state;
4029 if (state != PERF_EVENT_STATE_INACTIVE) {
4030 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4035 * May read while context is not active (e.g., thread is
4036 * blocked), in that case we cannot update context time
4038 if (ctx->is_active & EVENT_TIME) {
4039 update_context_time(ctx);
4040 update_cgrp_time_from_event(event);
4043 perf_event_update_time(event);
4045 perf_event_update_sibling_time(event);
4046 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4053 * Initialize the perf_event context in a task_struct:
4055 static void __perf_event_init_context(struct perf_event_context *ctx)
4057 raw_spin_lock_init(&ctx->lock);
4058 mutex_init(&ctx->mutex);
4059 INIT_LIST_HEAD(&ctx->active_ctx_list);
4060 perf_event_groups_init(&ctx->pinned_groups);
4061 perf_event_groups_init(&ctx->flexible_groups);
4062 INIT_LIST_HEAD(&ctx->event_list);
4063 INIT_LIST_HEAD(&ctx->pinned_active);
4064 INIT_LIST_HEAD(&ctx->flexible_active);
4065 atomic_set(&ctx->refcount, 1);
4068 static struct perf_event_context *
4069 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4071 struct perf_event_context *ctx;
4073 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4077 __perf_event_init_context(ctx);
4080 get_task_struct(task);
4087 static struct task_struct *
4088 find_lively_task_by_vpid(pid_t vpid)
4090 struct task_struct *task;
4096 task = find_task_by_vpid(vpid);
4098 get_task_struct(task);
4102 return ERR_PTR(-ESRCH);
4108 * Returns a matching context with refcount and pincount.
4110 static struct perf_event_context *
4111 find_get_context(struct pmu *pmu, struct task_struct *task,
4112 struct perf_event *event)
4114 struct perf_event_context *ctx, *clone_ctx = NULL;
4115 struct perf_cpu_context *cpuctx;
4116 void *task_ctx_data = NULL;
4117 unsigned long flags;
4119 int cpu = event->cpu;
4122 /* Must be root to operate on a CPU event: */
4123 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4124 return ERR_PTR(-EACCES);
4126 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4135 ctxn = pmu->task_ctx_nr;
4139 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4140 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4141 if (!task_ctx_data) {
4148 ctx = perf_lock_task_context(task, ctxn, &flags);
4150 clone_ctx = unclone_ctx(ctx);
4153 if (task_ctx_data && !ctx->task_ctx_data) {
4154 ctx->task_ctx_data = task_ctx_data;
4155 task_ctx_data = NULL;
4157 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4162 ctx = alloc_perf_context(pmu, task);
4167 if (task_ctx_data) {
4168 ctx->task_ctx_data = task_ctx_data;
4169 task_ctx_data = NULL;
4173 mutex_lock(&task->perf_event_mutex);
4175 * If it has already passed perf_event_exit_task().
4176 * we must see PF_EXITING, it takes this mutex too.
4178 if (task->flags & PF_EXITING)
4180 else if (task->perf_event_ctxp[ctxn])
4185 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4187 mutex_unlock(&task->perf_event_mutex);
4189 if (unlikely(err)) {
4198 kfree(task_ctx_data);
4202 kfree(task_ctx_data);
4203 return ERR_PTR(err);
4206 static void perf_event_free_filter(struct perf_event *event);
4207 static void perf_event_free_bpf_prog(struct perf_event *event);
4209 static void free_event_rcu(struct rcu_head *head)
4211 struct perf_event *event;
4213 event = container_of(head, struct perf_event, rcu_head);
4215 put_pid_ns(event->ns);
4216 perf_event_free_filter(event);
4220 static void ring_buffer_attach(struct perf_event *event,
4221 struct ring_buffer *rb);
4223 static void detach_sb_event(struct perf_event *event)
4225 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4227 raw_spin_lock(&pel->lock);
4228 list_del_rcu(&event->sb_list);
4229 raw_spin_unlock(&pel->lock);
4232 static bool is_sb_event(struct perf_event *event)
4234 struct perf_event_attr *attr = &event->attr;
4239 if (event->attach_state & PERF_ATTACH_TASK)
4242 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4243 attr->comm || attr->comm_exec ||
4245 attr->context_switch)
4250 static void unaccount_pmu_sb_event(struct perf_event *event)
4252 if (is_sb_event(event))
4253 detach_sb_event(event);
4256 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4261 if (is_cgroup_event(event))
4262 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4265 #ifdef CONFIG_NO_HZ_FULL
4266 static DEFINE_SPINLOCK(nr_freq_lock);
4269 static void unaccount_freq_event_nohz(void)
4271 #ifdef CONFIG_NO_HZ_FULL
4272 spin_lock(&nr_freq_lock);
4273 if (atomic_dec_and_test(&nr_freq_events))
4274 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4275 spin_unlock(&nr_freq_lock);
4279 static void unaccount_freq_event(void)
4281 if (tick_nohz_full_enabled())
4282 unaccount_freq_event_nohz();
4284 atomic_dec(&nr_freq_events);
4287 static void unaccount_event(struct perf_event *event)
4294 if (event->attach_state & PERF_ATTACH_TASK)
4296 if (event->attr.mmap || event->attr.mmap_data)
4297 atomic_dec(&nr_mmap_events);
4298 if (event->attr.comm)
4299 atomic_dec(&nr_comm_events);
4300 if (event->attr.namespaces)
4301 atomic_dec(&nr_namespaces_events);
4302 if (event->attr.task)
4303 atomic_dec(&nr_task_events);
4304 if (event->attr.freq)
4305 unaccount_freq_event();
4306 if (event->attr.context_switch) {
4308 atomic_dec(&nr_switch_events);
4310 if (is_cgroup_event(event))
4312 if (has_branch_stack(event))
4316 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4317 schedule_delayed_work(&perf_sched_work, HZ);
4320 unaccount_event_cpu(event, event->cpu);
4322 unaccount_pmu_sb_event(event);
4325 static void perf_sched_delayed(struct work_struct *work)
4327 mutex_lock(&perf_sched_mutex);
4328 if (atomic_dec_and_test(&perf_sched_count))
4329 static_branch_disable(&perf_sched_events);
4330 mutex_unlock(&perf_sched_mutex);
4334 * The following implement mutual exclusion of events on "exclusive" pmus
4335 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4336 * at a time, so we disallow creating events that might conflict, namely:
4338 * 1) cpu-wide events in the presence of per-task events,
4339 * 2) per-task events in the presence of cpu-wide events,
4340 * 3) two matching events on the same context.
4342 * The former two cases are handled in the allocation path (perf_event_alloc(),
4343 * _free_event()), the latter -- before the first perf_install_in_context().
4345 static int exclusive_event_init(struct perf_event *event)
4347 struct pmu *pmu = event->pmu;
4349 if (!is_exclusive_pmu(pmu))
4353 * Prevent co-existence of per-task and cpu-wide events on the
4354 * same exclusive pmu.
4356 * Negative pmu::exclusive_cnt means there are cpu-wide
4357 * events on this "exclusive" pmu, positive means there are
4360 * Since this is called in perf_event_alloc() path, event::ctx
4361 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4362 * to mean "per-task event", because unlike other attach states it
4363 * never gets cleared.
4365 if (event->attach_state & PERF_ATTACH_TASK) {
4366 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4369 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4376 static void exclusive_event_destroy(struct perf_event *event)
4378 struct pmu *pmu = event->pmu;
4380 if (!is_exclusive_pmu(pmu))
4383 /* see comment in exclusive_event_init() */
4384 if (event->attach_state & PERF_ATTACH_TASK)
4385 atomic_dec(&pmu->exclusive_cnt);
4387 atomic_inc(&pmu->exclusive_cnt);
4390 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4392 if ((e1->pmu == e2->pmu) &&
4393 (e1->cpu == e2->cpu ||
4400 static bool exclusive_event_installable(struct perf_event *event,
4401 struct perf_event_context *ctx)
4403 struct perf_event *iter_event;
4404 struct pmu *pmu = event->pmu;
4406 lockdep_assert_held(&ctx->mutex);
4408 if (!is_exclusive_pmu(pmu))
4411 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4412 if (exclusive_event_match(iter_event, event))
4419 static void perf_addr_filters_splice(struct perf_event *event,
4420 struct list_head *head);
4422 static void _free_event(struct perf_event *event)
4424 irq_work_sync(&event->pending);
4426 unaccount_event(event);
4430 * Can happen when we close an event with re-directed output.
4432 * Since we have a 0 refcount, perf_mmap_close() will skip
4433 * over us; possibly making our ring_buffer_put() the last.
4435 mutex_lock(&event->mmap_mutex);
4436 ring_buffer_attach(event, NULL);
4437 mutex_unlock(&event->mmap_mutex);
4440 if (is_cgroup_event(event))
4441 perf_detach_cgroup(event);
4443 if (!event->parent) {
4444 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4445 put_callchain_buffers();
4448 perf_event_free_bpf_prog(event);
4449 perf_addr_filters_splice(event, NULL);
4450 kfree(event->addr_filters_offs);
4453 event->destroy(event);
4456 * Must be after ->destroy(), due to uprobe_perf_close() using
4459 if (event->hw.target)
4460 put_task_struct(event->hw.target);
4463 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4464 * all task references must be cleaned up.
4467 put_ctx(event->ctx);
4469 exclusive_event_destroy(event);
4470 module_put(event->pmu->module);
4472 call_rcu(&event->rcu_head, free_event_rcu);
4476 * Used to free events which have a known refcount of 1, such as in error paths
4477 * where the event isn't exposed yet and inherited events.
4479 static void free_event(struct perf_event *event)
4481 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4482 "unexpected event refcount: %ld; ptr=%p\n",
4483 atomic_long_read(&event->refcount), event)) {
4484 /* leak to avoid use-after-free */
4492 * Remove user event from the owner task.
4494 static void perf_remove_from_owner(struct perf_event *event)
4496 struct task_struct *owner;
4500 * Matches the smp_store_release() in perf_event_exit_task(). If we
4501 * observe !owner it means the list deletion is complete and we can
4502 * indeed free this event, otherwise we need to serialize on
4503 * owner->perf_event_mutex.
4505 owner = READ_ONCE(event->owner);
4508 * Since delayed_put_task_struct() also drops the last
4509 * task reference we can safely take a new reference
4510 * while holding the rcu_read_lock().
4512 get_task_struct(owner);
4518 * If we're here through perf_event_exit_task() we're already
4519 * holding ctx->mutex which would be an inversion wrt. the
4520 * normal lock order.
4522 * However we can safely take this lock because its the child
4525 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4528 * We have to re-check the event->owner field, if it is cleared
4529 * we raced with perf_event_exit_task(), acquiring the mutex
4530 * ensured they're done, and we can proceed with freeing the
4534 list_del_init(&event->owner_entry);
4535 smp_store_release(&event->owner, NULL);
4537 mutex_unlock(&owner->perf_event_mutex);
4538 put_task_struct(owner);
4542 static void put_event(struct perf_event *event)
4544 if (!atomic_long_dec_and_test(&event->refcount))
4551 * Kill an event dead; while event:refcount will preserve the event
4552 * object, it will not preserve its functionality. Once the last 'user'
4553 * gives up the object, we'll destroy the thing.
4555 int perf_event_release_kernel(struct perf_event *event)
4557 struct perf_event_context *ctx = event->ctx;
4558 struct perf_event *child, *tmp;
4559 LIST_HEAD(free_list);
4562 * If we got here through err_file: fput(event_file); we will not have
4563 * attached to a context yet.
4566 WARN_ON_ONCE(event->attach_state &
4567 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4571 if (!is_kernel_event(event))
4572 perf_remove_from_owner(event);
4574 ctx = perf_event_ctx_lock(event);
4575 WARN_ON_ONCE(ctx->parent_ctx);
4576 perf_remove_from_context(event, DETACH_GROUP);
4578 raw_spin_lock_irq(&ctx->lock);
4580 * Mark this event as STATE_DEAD, there is no external reference to it
4583 * Anybody acquiring event->child_mutex after the below loop _must_
4584 * also see this, most importantly inherit_event() which will avoid
4585 * placing more children on the list.
4587 * Thus this guarantees that we will in fact observe and kill _ALL_
4590 event->state = PERF_EVENT_STATE_DEAD;
4591 raw_spin_unlock_irq(&ctx->lock);
4593 perf_event_ctx_unlock(event, ctx);
4596 mutex_lock(&event->child_mutex);
4597 list_for_each_entry(child, &event->child_list, child_list) {
4600 * Cannot change, child events are not migrated, see the
4601 * comment with perf_event_ctx_lock_nested().
4603 ctx = READ_ONCE(child->ctx);
4605 * Since child_mutex nests inside ctx::mutex, we must jump
4606 * through hoops. We start by grabbing a reference on the ctx.
4608 * Since the event cannot get freed while we hold the
4609 * child_mutex, the context must also exist and have a !0
4615 * Now that we have a ctx ref, we can drop child_mutex, and
4616 * acquire ctx::mutex without fear of it going away. Then we
4617 * can re-acquire child_mutex.
4619 mutex_unlock(&event->child_mutex);
4620 mutex_lock(&ctx->mutex);
4621 mutex_lock(&event->child_mutex);
4624 * Now that we hold ctx::mutex and child_mutex, revalidate our
4625 * state, if child is still the first entry, it didn't get freed
4626 * and we can continue doing so.
4628 tmp = list_first_entry_or_null(&event->child_list,
4629 struct perf_event, child_list);
4631 perf_remove_from_context(child, DETACH_GROUP);
4632 list_move(&child->child_list, &free_list);
4634 * This matches the refcount bump in inherit_event();
4635 * this can't be the last reference.
4640 mutex_unlock(&event->child_mutex);
4641 mutex_unlock(&ctx->mutex);
4645 mutex_unlock(&event->child_mutex);
4647 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4648 void *var = &child->ctx->refcount;
4650 list_del(&child->child_list);
4654 * Wake any perf_event_free_task() waiting for this event to be
4657 smp_mb(); /* pairs with wait_var_event() */
4662 put_event(event); /* Must be the 'last' reference */
4665 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4668 * Called when the last reference to the file is gone.
4670 static int perf_release(struct inode *inode, struct file *file)
4672 perf_event_release_kernel(file->private_data);
4676 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4678 struct perf_event *child;
4684 mutex_lock(&event->child_mutex);
4686 (void)perf_event_read(event, false);
4687 total += perf_event_count(event);
4689 *enabled += event->total_time_enabled +
4690 atomic64_read(&event->child_total_time_enabled);
4691 *running += event->total_time_running +
4692 atomic64_read(&event->child_total_time_running);
4694 list_for_each_entry(child, &event->child_list, child_list) {
4695 (void)perf_event_read(child, false);
4696 total += perf_event_count(child);
4697 *enabled += child->total_time_enabled;
4698 *running += child->total_time_running;
4700 mutex_unlock(&event->child_mutex);
4705 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4707 struct perf_event_context *ctx;
4710 ctx = perf_event_ctx_lock(event);
4711 count = __perf_event_read_value(event, enabled, running);
4712 perf_event_ctx_unlock(event, ctx);
4716 EXPORT_SYMBOL_GPL(perf_event_read_value);
4718 static int __perf_read_group_add(struct perf_event *leader,
4719 u64 read_format, u64 *values)
4721 struct perf_event_context *ctx = leader->ctx;
4722 struct perf_event *sub;
4723 unsigned long flags;
4724 int n = 1; /* skip @nr */
4727 ret = perf_event_read(leader, true);
4731 raw_spin_lock_irqsave(&ctx->lock, flags);
4734 * Since we co-schedule groups, {enabled,running} times of siblings
4735 * will be identical to those of the leader, so we only publish one
4738 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4739 values[n++] += leader->total_time_enabled +
4740 atomic64_read(&leader->child_total_time_enabled);
4743 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4744 values[n++] += leader->total_time_running +
4745 atomic64_read(&leader->child_total_time_running);
4749 * Write {count,id} tuples for every sibling.
4751 values[n++] += perf_event_count(leader);
4752 if (read_format & PERF_FORMAT_ID)
4753 values[n++] = primary_event_id(leader);
4755 for_each_sibling_event(sub, leader) {
4756 values[n++] += perf_event_count(sub);
4757 if (read_format & PERF_FORMAT_ID)
4758 values[n++] = primary_event_id(sub);
4761 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4765 static int perf_read_group(struct perf_event *event,
4766 u64 read_format, char __user *buf)
4768 struct perf_event *leader = event->group_leader, *child;
4769 struct perf_event_context *ctx = leader->ctx;
4773 lockdep_assert_held(&ctx->mutex);
4775 values = kzalloc(event->read_size, GFP_KERNEL);
4779 values[0] = 1 + leader->nr_siblings;
4782 * By locking the child_mutex of the leader we effectively
4783 * lock the child list of all siblings.. XXX explain how.
4785 mutex_lock(&leader->child_mutex);
4787 ret = __perf_read_group_add(leader, read_format, values);
4791 list_for_each_entry(child, &leader->child_list, child_list) {
4792 ret = __perf_read_group_add(child, read_format, values);
4797 mutex_unlock(&leader->child_mutex);
4799 ret = event->read_size;
4800 if (copy_to_user(buf, values, event->read_size))
4805 mutex_unlock(&leader->child_mutex);
4811 static int perf_read_one(struct perf_event *event,
4812 u64 read_format, char __user *buf)
4814 u64 enabled, running;
4818 values[n++] = __perf_event_read_value(event, &enabled, &running);
4819 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4820 values[n++] = enabled;
4821 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4822 values[n++] = running;
4823 if (read_format & PERF_FORMAT_ID)
4824 values[n++] = primary_event_id(event);
4826 if (copy_to_user(buf, values, n * sizeof(u64)))
4829 return n * sizeof(u64);
4832 static bool is_event_hup(struct perf_event *event)
4836 if (event->state > PERF_EVENT_STATE_EXIT)
4839 mutex_lock(&event->child_mutex);
4840 no_children = list_empty(&event->child_list);
4841 mutex_unlock(&event->child_mutex);
4846 * Read the performance event - simple non blocking version for now
4849 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4851 u64 read_format = event->attr.read_format;
4855 * Return end-of-file for a read on an event that is in
4856 * error state (i.e. because it was pinned but it couldn't be
4857 * scheduled on to the CPU at some point).
4859 if (event->state == PERF_EVENT_STATE_ERROR)
4862 if (count < event->read_size)
4865 WARN_ON_ONCE(event->ctx->parent_ctx);
4866 if (read_format & PERF_FORMAT_GROUP)
4867 ret = perf_read_group(event, read_format, buf);
4869 ret = perf_read_one(event, read_format, buf);
4875 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4877 struct perf_event *event = file->private_data;
4878 struct perf_event_context *ctx;
4881 ctx = perf_event_ctx_lock(event);
4882 ret = __perf_read(event, buf, count);
4883 perf_event_ctx_unlock(event, ctx);
4888 static __poll_t perf_poll(struct file *file, poll_table *wait)
4890 struct perf_event *event = file->private_data;
4891 struct ring_buffer *rb;
4892 __poll_t events = EPOLLHUP;
4894 poll_wait(file, &event->waitq, wait);
4896 if (is_event_hup(event))
4900 * Pin the event->rb by taking event->mmap_mutex; otherwise
4901 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4903 mutex_lock(&event->mmap_mutex);
4906 events = atomic_xchg(&rb->poll, 0);
4907 mutex_unlock(&event->mmap_mutex);
4911 static void _perf_event_reset(struct perf_event *event)
4913 (void)perf_event_read(event, false);
4914 local64_set(&event->count, 0);
4915 perf_event_update_userpage(event);
4919 * Holding the top-level event's child_mutex means that any
4920 * descendant process that has inherited this event will block
4921 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4922 * task existence requirements of perf_event_enable/disable.
4924 static void perf_event_for_each_child(struct perf_event *event,
4925 void (*func)(struct perf_event *))
4927 struct perf_event *child;
4929 WARN_ON_ONCE(event->ctx->parent_ctx);
4931 mutex_lock(&event->child_mutex);
4933 list_for_each_entry(child, &event->child_list, child_list)
4935 mutex_unlock(&event->child_mutex);
4938 static void perf_event_for_each(struct perf_event *event,
4939 void (*func)(struct perf_event *))
4941 struct perf_event_context *ctx = event->ctx;
4942 struct perf_event *sibling;
4944 lockdep_assert_held(&ctx->mutex);
4946 event = event->group_leader;
4948 perf_event_for_each_child(event, func);
4949 for_each_sibling_event(sibling, event)
4950 perf_event_for_each_child(sibling, func);
4953 static void __perf_event_period(struct perf_event *event,
4954 struct perf_cpu_context *cpuctx,
4955 struct perf_event_context *ctx,
4958 u64 value = *((u64 *)info);
4961 if (event->attr.freq) {
4962 event->attr.sample_freq = value;
4964 event->attr.sample_period = value;
4965 event->hw.sample_period = value;
4968 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4970 perf_pmu_disable(ctx->pmu);
4972 * We could be throttled; unthrottle now to avoid the tick
4973 * trying to unthrottle while we already re-started the event.
4975 if (event->hw.interrupts == MAX_INTERRUPTS) {
4976 event->hw.interrupts = 0;
4977 perf_log_throttle(event, 1);
4979 event->pmu->stop(event, PERF_EF_UPDATE);
4982 local64_set(&event->hw.period_left, 0);
4985 event->pmu->start(event, PERF_EF_RELOAD);
4986 perf_pmu_enable(ctx->pmu);
4990 static int perf_event_check_period(struct perf_event *event, u64 value)
4992 return event->pmu->check_period(event, value);
4995 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4999 if (!is_sampling_event(event))
5002 if (copy_from_user(&value, arg, sizeof(value)))
5008 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5011 if (perf_event_check_period(event, value))
5014 event_function_call(event, __perf_event_period, &value);
5019 static const struct file_operations perf_fops;
5021 static inline int perf_fget_light(int fd, struct fd *p)
5023 struct fd f = fdget(fd);
5027 if (f.file->f_op != &perf_fops) {
5035 static int perf_event_set_output(struct perf_event *event,
5036 struct perf_event *output_event);
5037 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5038 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5039 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5040 struct perf_event_attr *attr);
5042 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5044 void (*func)(struct perf_event *);
5048 case PERF_EVENT_IOC_ENABLE:
5049 func = _perf_event_enable;
5051 case PERF_EVENT_IOC_DISABLE:
5052 func = _perf_event_disable;
5054 case PERF_EVENT_IOC_RESET:
5055 func = _perf_event_reset;
5058 case PERF_EVENT_IOC_REFRESH:
5059 return _perf_event_refresh(event, arg);
5061 case PERF_EVENT_IOC_PERIOD:
5062 return perf_event_period(event, (u64 __user *)arg);
5064 case PERF_EVENT_IOC_ID:
5066 u64 id = primary_event_id(event);
5068 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5073 case PERF_EVENT_IOC_SET_OUTPUT:
5077 struct perf_event *output_event;
5079 ret = perf_fget_light(arg, &output);
5082 output_event = output.file->private_data;
5083 ret = perf_event_set_output(event, output_event);
5086 ret = perf_event_set_output(event, NULL);
5091 case PERF_EVENT_IOC_SET_FILTER:
5092 return perf_event_set_filter(event, (void __user *)arg);
5094 case PERF_EVENT_IOC_SET_BPF:
5095 return perf_event_set_bpf_prog(event, arg);
5097 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5098 struct ring_buffer *rb;
5101 rb = rcu_dereference(event->rb);
5102 if (!rb || !rb->nr_pages) {
5106 rb_toggle_paused(rb, !!arg);
5111 case PERF_EVENT_IOC_QUERY_BPF:
5112 return perf_event_query_prog_array(event, (void __user *)arg);
5114 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5115 struct perf_event_attr new_attr;
5116 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5122 return perf_event_modify_attr(event, &new_attr);
5128 if (flags & PERF_IOC_FLAG_GROUP)
5129 perf_event_for_each(event, func);
5131 perf_event_for_each_child(event, func);
5136 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5138 struct perf_event *event = file->private_data;
5139 struct perf_event_context *ctx;
5142 ctx = perf_event_ctx_lock(event);
5143 ret = _perf_ioctl(event, cmd, arg);
5144 perf_event_ctx_unlock(event, ctx);
5149 #ifdef CONFIG_COMPAT
5150 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5153 switch (_IOC_NR(cmd)) {
5154 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5155 case _IOC_NR(PERF_EVENT_IOC_ID):
5156 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5157 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5158 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5159 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5160 cmd &= ~IOCSIZE_MASK;
5161 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5165 return perf_ioctl(file, cmd, arg);
5168 # define perf_compat_ioctl NULL
5171 int perf_event_task_enable(void)
5173 struct perf_event_context *ctx;
5174 struct perf_event *event;
5176 mutex_lock(¤t->perf_event_mutex);
5177 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5178 ctx = perf_event_ctx_lock(event);
5179 perf_event_for_each_child(event, _perf_event_enable);
5180 perf_event_ctx_unlock(event, ctx);
5182 mutex_unlock(¤t->perf_event_mutex);
5187 int perf_event_task_disable(void)
5189 struct perf_event_context *ctx;
5190 struct perf_event *event;
5192 mutex_lock(¤t->perf_event_mutex);
5193 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5194 ctx = perf_event_ctx_lock(event);
5195 perf_event_for_each_child(event, _perf_event_disable);
5196 perf_event_ctx_unlock(event, ctx);
5198 mutex_unlock(¤t->perf_event_mutex);
5203 static int perf_event_index(struct perf_event *event)
5205 if (event->hw.state & PERF_HES_STOPPED)
5208 if (event->state != PERF_EVENT_STATE_ACTIVE)
5211 return event->pmu->event_idx(event);
5214 static void calc_timer_values(struct perf_event *event,
5221 *now = perf_clock();
5222 ctx_time = event->shadow_ctx_time + *now;
5223 __perf_update_times(event, ctx_time, enabled, running);
5226 static void perf_event_init_userpage(struct perf_event *event)
5228 struct perf_event_mmap_page *userpg;
5229 struct ring_buffer *rb;
5232 rb = rcu_dereference(event->rb);
5236 userpg = rb->user_page;
5238 /* Allow new userspace to detect that bit 0 is deprecated */
5239 userpg->cap_bit0_is_deprecated = 1;
5240 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5241 userpg->data_offset = PAGE_SIZE;
5242 userpg->data_size = perf_data_size(rb);
5248 void __weak arch_perf_update_userpage(
5249 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5254 * Callers need to ensure there can be no nesting of this function, otherwise
5255 * the seqlock logic goes bad. We can not serialize this because the arch
5256 * code calls this from NMI context.
5258 void perf_event_update_userpage(struct perf_event *event)
5260 struct perf_event_mmap_page *userpg;
5261 struct ring_buffer *rb;
5262 u64 enabled, running, now;
5265 rb = rcu_dereference(event->rb);
5270 * compute total_time_enabled, total_time_running
5271 * based on snapshot values taken when the event
5272 * was last scheduled in.
5274 * we cannot simply called update_context_time()
5275 * because of locking issue as we can be called in
5278 calc_timer_values(event, &now, &enabled, &running);
5280 userpg = rb->user_page;
5282 * Disable preemption to guarantee consistent time stamps are stored to
5288 userpg->index = perf_event_index(event);
5289 userpg->offset = perf_event_count(event);
5291 userpg->offset -= local64_read(&event->hw.prev_count);
5293 userpg->time_enabled = enabled +
5294 atomic64_read(&event->child_total_time_enabled);
5296 userpg->time_running = running +
5297 atomic64_read(&event->child_total_time_running);
5299 arch_perf_update_userpage(event, userpg, now);
5307 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5309 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5311 struct perf_event *event = vmf->vma->vm_file->private_data;
5312 struct ring_buffer *rb;
5313 vm_fault_t ret = VM_FAULT_SIGBUS;
5315 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5316 if (vmf->pgoff == 0)
5322 rb = rcu_dereference(event->rb);
5326 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5329 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5333 get_page(vmf->page);
5334 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5335 vmf->page->index = vmf->pgoff;
5344 static void ring_buffer_attach(struct perf_event *event,
5345 struct ring_buffer *rb)
5347 struct ring_buffer *old_rb = NULL;
5348 unsigned long flags;
5352 * Should be impossible, we set this when removing
5353 * event->rb_entry and wait/clear when adding event->rb_entry.
5355 WARN_ON_ONCE(event->rcu_pending);
5358 spin_lock_irqsave(&old_rb->event_lock, flags);
5359 list_del_rcu(&event->rb_entry);
5360 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5362 event->rcu_batches = get_state_synchronize_rcu();
5363 event->rcu_pending = 1;
5367 if (event->rcu_pending) {
5368 cond_synchronize_rcu(event->rcu_batches);
5369 event->rcu_pending = 0;
5372 spin_lock_irqsave(&rb->event_lock, flags);
5373 list_add_rcu(&event->rb_entry, &rb->event_list);
5374 spin_unlock_irqrestore(&rb->event_lock, flags);
5378 * Avoid racing with perf_mmap_close(AUX): stop the event
5379 * before swizzling the event::rb pointer; if it's getting
5380 * unmapped, its aux_mmap_count will be 0 and it won't
5381 * restart. See the comment in __perf_pmu_output_stop().
5383 * Data will inevitably be lost when set_output is done in
5384 * mid-air, but then again, whoever does it like this is
5385 * not in for the data anyway.
5388 perf_event_stop(event, 0);
5390 rcu_assign_pointer(event->rb, rb);
5393 ring_buffer_put(old_rb);
5395 * Since we detached before setting the new rb, so that we
5396 * could attach the new rb, we could have missed a wakeup.
5399 wake_up_all(&event->waitq);
5403 static void ring_buffer_wakeup(struct perf_event *event)
5405 struct ring_buffer *rb;
5408 rb = rcu_dereference(event->rb);
5410 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5411 wake_up_all(&event->waitq);
5416 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5418 struct ring_buffer *rb;
5421 rb = rcu_dereference(event->rb);
5423 if (!atomic_inc_not_zero(&rb->refcount))
5431 void ring_buffer_put(struct ring_buffer *rb)
5433 if (!atomic_dec_and_test(&rb->refcount))
5436 WARN_ON_ONCE(!list_empty(&rb->event_list));
5438 call_rcu(&rb->rcu_head, rb_free_rcu);
5441 static void perf_mmap_open(struct vm_area_struct *vma)
5443 struct perf_event *event = vma->vm_file->private_data;
5445 atomic_inc(&event->mmap_count);
5446 atomic_inc(&event->rb->mmap_count);
5449 atomic_inc(&event->rb->aux_mmap_count);
5451 if (event->pmu->event_mapped)
5452 event->pmu->event_mapped(event, vma->vm_mm);
5455 static void perf_pmu_output_stop(struct perf_event *event);
5458 * A buffer can be mmap()ed multiple times; either directly through the same
5459 * event, or through other events by use of perf_event_set_output().
5461 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5462 * the buffer here, where we still have a VM context. This means we need
5463 * to detach all events redirecting to us.
5465 static void perf_mmap_close(struct vm_area_struct *vma)
5467 struct perf_event *event = vma->vm_file->private_data;
5469 struct ring_buffer *rb = ring_buffer_get(event);
5470 struct user_struct *mmap_user = rb->mmap_user;
5471 int mmap_locked = rb->mmap_locked;
5472 unsigned long size = perf_data_size(rb);
5474 if (event->pmu->event_unmapped)
5475 event->pmu->event_unmapped(event, vma->vm_mm);
5478 * rb->aux_mmap_count will always drop before rb->mmap_count and
5479 * event->mmap_count, so it is ok to use event->mmap_mutex to
5480 * serialize with perf_mmap here.
5482 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5483 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5485 * Stop all AUX events that are writing to this buffer,
5486 * so that we can free its AUX pages and corresponding PMU
5487 * data. Note that after rb::aux_mmap_count dropped to zero,
5488 * they won't start any more (see perf_aux_output_begin()).
5490 perf_pmu_output_stop(event);
5492 /* now it's safe to free the pages */
5493 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5494 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5496 /* this has to be the last one */
5498 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5500 mutex_unlock(&event->mmap_mutex);
5503 atomic_dec(&rb->mmap_count);
5505 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5508 ring_buffer_attach(event, NULL);
5509 mutex_unlock(&event->mmap_mutex);
5511 /* If there's still other mmap()s of this buffer, we're done. */
5512 if (atomic_read(&rb->mmap_count))
5516 * No other mmap()s, detach from all other events that might redirect
5517 * into the now unreachable buffer. Somewhat complicated by the
5518 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5522 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5523 if (!atomic_long_inc_not_zero(&event->refcount)) {
5525 * This event is en-route to free_event() which will
5526 * detach it and remove it from the list.
5532 mutex_lock(&event->mmap_mutex);
5534 * Check we didn't race with perf_event_set_output() which can
5535 * swizzle the rb from under us while we were waiting to
5536 * acquire mmap_mutex.
5538 * If we find a different rb; ignore this event, a next
5539 * iteration will no longer find it on the list. We have to
5540 * still restart the iteration to make sure we're not now
5541 * iterating the wrong list.
5543 if (event->rb == rb)
5544 ring_buffer_attach(event, NULL);
5546 mutex_unlock(&event->mmap_mutex);
5550 * Restart the iteration; either we're on the wrong list or
5551 * destroyed its integrity by doing a deletion.
5558 * It could be there's still a few 0-ref events on the list; they'll
5559 * get cleaned up by free_event() -- they'll also still have their
5560 * ref on the rb and will free it whenever they are done with it.
5562 * Aside from that, this buffer is 'fully' detached and unmapped,
5563 * undo the VM accounting.
5566 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5567 vma->vm_mm->pinned_vm -= mmap_locked;
5568 free_uid(mmap_user);
5571 ring_buffer_put(rb); /* could be last */
5574 static const struct vm_operations_struct perf_mmap_vmops = {
5575 .open = perf_mmap_open,
5576 .close = perf_mmap_close, /* non mergable */
5577 .fault = perf_mmap_fault,
5578 .page_mkwrite = perf_mmap_fault,
5581 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5583 struct perf_event *event = file->private_data;
5584 unsigned long user_locked, user_lock_limit;
5585 struct user_struct *user = current_user();
5586 unsigned long locked, lock_limit;
5587 struct ring_buffer *rb = NULL;
5588 unsigned long vma_size;
5589 unsigned long nr_pages;
5590 long user_extra = 0, extra = 0;
5591 int ret = 0, flags = 0;
5594 * Don't allow mmap() of inherited per-task counters. This would
5595 * create a performance issue due to all children writing to the
5598 if (event->cpu == -1 && event->attr.inherit)
5601 if (!(vma->vm_flags & VM_SHARED))
5604 vma_size = vma->vm_end - vma->vm_start;
5606 if (vma->vm_pgoff == 0) {
5607 nr_pages = (vma_size / PAGE_SIZE) - 1;
5610 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5611 * mapped, all subsequent mappings should have the same size
5612 * and offset. Must be above the normal perf buffer.
5614 u64 aux_offset, aux_size;
5619 nr_pages = vma_size / PAGE_SIZE;
5621 mutex_lock(&event->mmap_mutex);
5628 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5629 aux_size = READ_ONCE(rb->user_page->aux_size);
5631 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5634 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5637 /* already mapped with a different offset */
5638 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5641 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5644 /* already mapped with a different size */
5645 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5648 if (!is_power_of_2(nr_pages))
5651 if (!atomic_inc_not_zero(&rb->mmap_count))
5654 if (rb_has_aux(rb)) {
5655 atomic_inc(&rb->aux_mmap_count);
5660 atomic_set(&rb->aux_mmap_count, 1);
5661 user_extra = nr_pages;
5667 * If we have rb pages ensure they're a power-of-two number, so we
5668 * can do bitmasks instead of modulo.
5670 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5673 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5676 WARN_ON_ONCE(event->ctx->parent_ctx);
5678 mutex_lock(&event->mmap_mutex);
5680 if (event->rb->nr_pages != nr_pages) {
5685 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5687 * Raced against perf_mmap_close() through
5688 * perf_event_set_output(). Try again, hope for better
5691 mutex_unlock(&event->mmap_mutex);
5698 user_extra = nr_pages + 1;
5701 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5704 * Increase the limit linearly with more CPUs:
5706 user_lock_limit *= num_online_cpus();
5708 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5710 if (user_locked > user_lock_limit)
5711 extra = user_locked - user_lock_limit;
5713 lock_limit = rlimit(RLIMIT_MEMLOCK);
5714 lock_limit >>= PAGE_SHIFT;
5715 locked = vma->vm_mm->pinned_vm + extra;
5717 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5718 !capable(CAP_IPC_LOCK)) {
5723 WARN_ON(!rb && event->rb);
5725 if (vma->vm_flags & VM_WRITE)
5726 flags |= RING_BUFFER_WRITABLE;
5729 rb = rb_alloc(nr_pages,
5730 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5738 atomic_set(&rb->mmap_count, 1);
5739 rb->mmap_user = get_current_user();
5740 rb->mmap_locked = extra;
5742 ring_buffer_attach(event, rb);
5744 perf_event_init_userpage(event);
5745 perf_event_update_userpage(event);
5747 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5748 event->attr.aux_watermark, flags);
5750 rb->aux_mmap_locked = extra;
5755 atomic_long_add(user_extra, &user->locked_vm);
5756 vma->vm_mm->pinned_vm += extra;
5758 atomic_inc(&event->mmap_count);
5760 atomic_dec(&rb->mmap_count);
5763 mutex_unlock(&event->mmap_mutex);
5766 * Since pinned accounting is per vm we cannot allow fork() to copy our
5769 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5770 vma->vm_ops = &perf_mmap_vmops;
5772 if (event->pmu->event_mapped)
5773 event->pmu->event_mapped(event, vma->vm_mm);
5778 static int perf_fasync(int fd, struct file *filp, int on)
5780 struct inode *inode = file_inode(filp);
5781 struct perf_event *event = filp->private_data;
5785 retval = fasync_helper(fd, filp, on, &event->fasync);
5786 inode_unlock(inode);
5794 static const struct file_operations perf_fops = {
5795 .llseek = no_llseek,
5796 .release = perf_release,
5799 .unlocked_ioctl = perf_ioctl,
5800 .compat_ioctl = perf_compat_ioctl,
5802 .fasync = perf_fasync,
5808 * If there's data, ensure we set the poll() state and publish everything
5809 * to user-space before waking everybody up.
5812 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5814 /* only the parent has fasync state */
5816 event = event->parent;
5817 return &event->fasync;
5820 void perf_event_wakeup(struct perf_event *event)
5822 ring_buffer_wakeup(event);
5824 if (event->pending_kill) {
5825 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5826 event->pending_kill = 0;
5830 static void perf_pending_event_disable(struct perf_event *event)
5832 int cpu = READ_ONCE(event->pending_disable);
5837 if (cpu == smp_processor_id()) {
5838 WRITE_ONCE(event->pending_disable, -1);
5839 perf_event_disable_local(event);
5846 * perf_event_disable_inatomic()
5847 * @pending_disable = CPU-A;
5851 * @pending_disable = -1;
5854 * perf_event_disable_inatomic()
5855 * @pending_disable = CPU-B;
5856 * irq_work_queue(); // FAILS
5859 * perf_pending_event()
5861 * But the event runs on CPU-B and wants disabling there.
5863 irq_work_queue_on(&event->pending, cpu);
5866 static void perf_pending_event(struct irq_work *entry)
5868 struct perf_event *event = container_of(entry, struct perf_event, pending);
5871 rctx = perf_swevent_get_recursion_context();
5873 * If we 'fail' here, that's OK, it means recursion is already disabled
5874 * and we won't recurse 'further'.
5877 perf_pending_event_disable(event);
5879 if (event->pending_wakeup) {
5880 event->pending_wakeup = 0;
5881 perf_event_wakeup(event);
5885 perf_swevent_put_recursion_context(rctx);
5889 * We assume there is only KVM supporting the callbacks.
5890 * Later on, we might change it to a list if there is
5891 * another virtualization implementation supporting the callbacks.
5893 struct perf_guest_info_callbacks *perf_guest_cbs;
5895 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5897 perf_guest_cbs = cbs;
5900 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5902 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5904 perf_guest_cbs = NULL;
5907 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5910 perf_output_sample_regs(struct perf_output_handle *handle,
5911 struct pt_regs *regs, u64 mask)
5914 DECLARE_BITMAP(_mask, 64);
5916 bitmap_from_u64(_mask, mask);
5917 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5920 val = perf_reg_value(regs, bit);
5921 perf_output_put(handle, val);
5925 static void perf_sample_regs_user(struct perf_regs *regs_user,
5926 struct pt_regs *regs,
5927 struct pt_regs *regs_user_copy)
5929 if (user_mode(regs)) {
5930 regs_user->abi = perf_reg_abi(current);
5931 regs_user->regs = regs;
5932 } else if (!(current->flags & PF_KTHREAD)) {
5933 perf_get_regs_user(regs_user, regs, regs_user_copy);
5935 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5936 regs_user->regs = NULL;
5940 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5941 struct pt_regs *regs)
5943 regs_intr->regs = regs;
5944 regs_intr->abi = perf_reg_abi(current);
5949 * Get remaining task size from user stack pointer.
5951 * It'd be better to take stack vma map and limit this more
5952 * precisly, but there's no way to get it safely under interrupt,
5953 * so using TASK_SIZE as limit.
5955 static u64 perf_ustack_task_size(struct pt_regs *regs)
5957 unsigned long addr = perf_user_stack_pointer(regs);
5959 if (!addr || addr >= TASK_SIZE)
5962 return TASK_SIZE - addr;
5966 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5967 struct pt_regs *regs)
5971 /* No regs, no stack pointer, no dump. */
5976 * Check if we fit in with the requested stack size into the:
5978 * If we don't, we limit the size to the TASK_SIZE.
5980 * - remaining sample size
5981 * If we don't, we customize the stack size to
5982 * fit in to the remaining sample size.
5985 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5986 stack_size = min(stack_size, (u16) task_size);
5988 /* Current header size plus static size and dynamic size. */
5989 header_size += 2 * sizeof(u64);
5991 /* Do we fit in with the current stack dump size? */
5992 if ((u16) (header_size + stack_size) < header_size) {
5994 * If we overflow the maximum size for the sample,
5995 * we customize the stack dump size to fit in.
5997 stack_size = USHRT_MAX - header_size - sizeof(u64);
5998 stack_size = round_up(stack_size, sizeof(u64));
6005 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6006 struct pt_regs *regs)
6008 /* Case of a kernel thread, nothing to dump */
6011 perf_output_put(handle, size);
6021 * - the size requested by user or the best one we can fit
6022 * in to the sample max size
6024 * - user stack dump data
6026 * - the actual dumped size
6030 perf_output_put(handle, dump_size);
6033 sp = perf_user_stack_pointer(regs);
6036 rem = __output_copy_user(handle, (void *) sp, dump_size);
6038 dyn_size = dump_size - rem;
6040 perf_output_skip(handle, rem);
6043 perf_output_put(handle, dyn_size);
6047 static void __perf_event_header__init_id(struct perf_event_header *header,
6048 struct perf_sample_data *data,
6049 struct perf_event *event)
6051 u64 sample_type = event->attr.sample_type;
6053 data->type = sample_type;
6054 header->size += event->id_header_size;
6056 if (sample_type & PERF_SAMPLE_TID) {
6057 /* namespace issues */
6058 data->tid_entry.pid = perf_event_pid(event, current);
6059 data->tid_entry.tid = perf_event_tid(event, current);
6062 if (sample_type & PERF_SAMPLE_TIME)
6063 data->time = perf_event_clock(event);
6065 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6066 data->id = primary_event_id(event);
6068 if (sample_type & PERF_SAMPLE_STREAM_ID)
6069 data->stream_id = event->id;
6071 if (sample_type & PERF_SAMPLE_CPU) {
6072 data->cpu_entry.cpu = raw_smp_processor_id();
6073 data->cpu_entry.reserved = 0;
6077 void perf_event_header__init_id(struct perf_event_header *header,
6078 struct perf_sample_data *data,
6079 struct perf_event *event)
6081 if (event->attr.sample_id_all)
6082 __perf_event_header__init_id(header, data, event);
6085 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6086 struct perf_sample_data *data)
6088 u64 sample_type = data->type;
6090 if (sample_type & PERF_SAMPLE_TID)
6091 perf_output_put(handle, data->tid_entry);
6093 if (sample_type & PERF_SAMPLE_TIME)
6094 perf_output_put(handle, data->time);
6096 if (sample_type & PERF_SAMPLE_ID)
6097 perf_output_put(handle, data->id);
6099 if (sample_type & PERF_SAMPLE_STREAM_ID)
6100 perf_output_put(handle, data->stream_id);
6102 if (sample_type & PERF_SAMPLE_CPU)
6103 perf_output_put(handle, data->cpu_entry);
6105 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6106 perf_output_put(handle, data->id);
6109 void perf_event__output_id_sample(struct perf_event *event,
6110 struct perf_output_handle *handle,
6111 struct perf_sample_data *sample)
6113 if (event->attr.sample_id_all)
6114 __perf_event__output_id_sample(handle, sample);
6117 static void perf_output_read_one(struct perf_output_handle *handle,
6118 struct perf_event *event,
6119 u64 enabled, u64 running)
6121 u64 read_format = event->attr.read_format;
6125 values[n++] = perf_event_count(event);
6126 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6127 values[n++] = enabled +
6128 atomic64_read(&event->child_total_time_enabled);
6130 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6131 values[n++] = running +
6132 atomic64_read(&event->child_total_time_running);
6134 if (read_format & PERF_FORMAT_ID)
6135 values[n++] = primary_event_id(event);
6137 __output_copy(handle, values, n * sizeof(u64));
6140 static void perf_output_read_group(struct perf_output_handle *handle,
6141 struct perf_event *event,
6142 u64 enabled, u64 running)
6144 struct perf_event *leader = event->group_leader, *sub;
6145 u64 read_format = event->attr.read_format;
6149 values[n++] = 1 + leader->nr_siblings;
6151 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6152 values[n++] = enabled;
6154 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6155 values[n++] = running;
6157 if ((leader != event) &&
6158 (leader->state == PERF_EVENT_STATE_ACTIVE))
6159 leader->pmu->read(leader);
6161 values[n++] = perf_event_count(leader);
6162 if (read_format & PERF_FORMAT_ID)
6163 values[n++] = primary_event_id(leader);
6165 __output_copy(handle, values, n * sizeof(u64));
6167 for_each_sibling_event(sub, leader) {
6170 if ((sub != event) &&
6171 (sub->state == PERF_EVENT_STATE_ACTIVE))
6172 sub->pmu->read(sub);
6174 values[n++] = perf_event_count(sub);
6175 if (read_format & PERF_FORMAT_ID)
6176 values[n++] = primary_event_id(sub);
6178 __output_copy(handle, values, n * sizeof(u64));
6182 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6183 PERF_FORMAT_TOTAL_TIME_RUNNING)
6186 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6188 * The problem is that its both hard and excessively expensive to iterate the
6189 * child list, not to mention that its impossible to IPI the children running
6190 * on another CPU, from interrupt/NMI context.
6192 static void perf_output_read(struct perf_output_handle *handle,
6193 struct perf_event *event)
6195 u64 enabled = 0, running = 0, now;
6196 u64 read_format = event->attr.read_format;
6199 * compute total_time_enabled, total_time_running
6200 * based on snapshot values taken when the event
6201 * was last scheduled in.
6203 * we cannot simply called update_context_time()
6204 * because of locking issue as we are called in
6207 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6208 calc_timer_values(event, &now, &enabled, &running);
6210 if (event->attr.read_format & PERF_FORMAT_GROUP)
6211 perf_output_read_group(handle, event, enabled, running);
6213 perf_output_read_one(handle, event, enabled, running);
6216 void perf_output_sample(struct perf_output_handle *handle,
6217 struct perf_event_header *header,
6218 struct perf_sample_data *data,
6219 struct perf_event *event)
6221 u64 sample_type = data->type;
6223 perf_output_put(handle, *header);
6225 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6226 perf_output_put(handle, data->id);
6228 if (sample_type & PERF_SAMPLE_IP)
6229 perf_output_put(handle, data->ip);
6231 if (sample_type & PERF_SAMPLE_TID)
6232 perf_output_put(handle, data->tid_entry);
6234 if (sample_type & PERF_SAMPLE_TIME)
6235 perf_output_put(handle, data->time);
6237 if (sample_type & PERF_SAMPLE_ADDR)
6238 perf_output_put(handle, data->addr);
6240 if (sample_type & PERF_SAMPLE_ID)
6241 perf_output_put(handle, data->id);
6243 if (sample_type & PERF_SAMPLE_STREAM_ID)
6244 perf_output_put(handle, data->stream_id);
6246 if (sample_type & PERF_SAMPLE_CPU)
6247 perf_output_put(handle, data->cpu_entry);
6249 if (sample_type & PERF_SAMPLE_PERIOD)
6250 perf_output_put(handle, data->period);
6252 if (sample_type & PERF_SAMPLE_READ)
6253 perf_output_read(handle, event);
6255 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6258 size += data->callchain->nr;
6259 size *= sizeof(u64);
6260 __output_copy(handle, data->callchain, size);
6263 if (sample_type & PERF_SAMPLE_RAW) {
6264 struct perf_raw_record *raw = data->raw;
6267 struct perf_raw_frag *frag = &raw->frag;
6269 perf_output_put(handle, raw->size);
6272 __output_custom(handle, frag->copy,
6273 frag->data, frag->size);
6275 __output_copy(handle, frag->data,
6278 if (perf_raw_frag_last(frag))
6283 __output_skip(handle, NULL, frag->pad);
6289 .size = sizeof(u32),
6292 perf_output_put(handle, raw);
6296 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6297 if (data->br_stack) {
6300 size = data->br_stack->nr
6301 * sizeof(struct perf_branch_entry);
6303 perf_output_put(handle, data->br_stack->nr);
6304 perf_output_copy(handle, data->br_stack->entries, size);
6307 * we always store at least the value of nr
6310 perf_output_put(handle, nr);
6314 if (sample_type & PERF_SAMPLE_REGS_USER) {
6315 u64 abi = data->regs_user.abi;
6318 * If there are no regs to dump, notice it through
6319 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6321 perf_output_put(handle, abi);
6324 u64 mask = event->attr.sample_regs_user;
6325 perf_output_sample_regs(handle,
6326 data->regs_user.regs,
6331 if (sample_type & PERF_SAMPLE_STACK_USER) {
6332 perf_output_sample_ustack(handle,
6333 data->stack_user_size,
6334 data->regs_user.regs);
6337 if (sample_type & PERF_SAMPLE_WEIGHT)
6338 perf_output_put(handle, data->weight);
6340 if (sample_type & PERF_SAMPLE_DATA_SRC)
6341 perf_output_put(handle, data->data_src.val);
6343 if (sample_type & PERF_SAMPLE_TRANSACTION)
6344 perf_output_put(handle, data->txn);
6346 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6347 u64 abi = data->regs_intr.abi;
6349 * If there are no regs to dump, notice it through
6350 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6352 perf_output_put(handle, abi);
6355 u64 mask = event->attr.sample_regs_intr;
6357 perf_output_sample_regs(handle,
6358 data->regs_intr.regs,
6363 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6364 perf_output_put(handle, data->phys_addr);
6366 if (!event->attr.watermark) {
6367 int wakeup_events = event->attr.wakeup_events;
6369 if (wakeup_events) {
6370 struct ring_buffer *rb = handle->rb;
6371 int events = local_inc_return(&rb->events);
6373 if (events >= wakeup_events) {
6374 local_sub(wakeup_events, &rb->events);
6375 local_inc(&rb->wakeup);
6381 static u64 perf_virt_to_phys(u64 virt)
6384 struct page *p = NULL;
6389 if (virt >= TASK_SIZE) {
6390 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6391 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6392 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6393 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6396 * Walking the pages tables for user address.
6397 * Interrupts are disabled, so it prevents any tear down
6398 * of the page tables.
6399 * Try IRQ-safe __get_user_pages_fast first.
6400 * If failed, leave phys_addr as 0.
6402 if ((current->mm != NULL) &&
6403 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6404 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6413 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6415 struct perf_callchain_entry *
6416 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6418 bool kernel = !event->attr.exclude_callchain_kernel;
6419 bool user = !event->attr.exclude_callchain_user;
6420 /* Disallow cross-task user callchains. */
6421 bool crosstask = event->ctx->task && event->ctx->task != current;
6422 const u32 max_stack = event->attr.sample_max_stack;
6423 struct perf_callchain_entry *callchain;
6425 if (!kernel && !user)
6426 return &__empty_callchain;
6428 callchain = get_perf_callchain(regs, 0, kernel, user,
6429 max_stack, crosstask, true);
6430 return callchain ?: &__empty_callchain;
6433 void perf_prepare_sample(struct perf_event_header *header,
6434 struct perf_sample_data *data,
6435 struct perf_event *event,
6436 struct pt_regs *regs)
6438 u64 sample_type = event->attr.sample_type;
6440 header->type = PERF_RECORD_SAMPLE;
6441 header->size = sizeof(*header) + event->header_size;
6444 header->misc |= perf_misc_flags(regs);
6446 __perf_event_header__init_id(header, data, event);
6448 if (sample_type & PERF_SAMPLE_IP)
6449 data->ip = perf_instruction_pointer(regs);
6451 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6454 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6455 data->callchain = perf_callchain(event, regs);
6457 size += data->callchain->nr;
6459 header->size += size * sizeof(u64);
6462 if (sample_type & PERF_SAMPLE_RAW) {
6463 struct perf_raw_record *raw = data->raw;
6467 struct perf_raw_frag *frag = &raw->frag;
6472 if (perf_raw_frag_last(frag))
6477 size = round_up(sum + sizeof(u32), sizeof(u64));
6478 raw->size = size - sizeof(u32);
6479 frag->pad = raw->size - sum;
6484 header->size += size;
6487 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6488 int size = sizeof(u64); /* nr */
6489 if (data->br_stack) {
6490 size += data->br_stack->nr
6491 * sizeof(struct perf_branch_entry);
6493 header->size += size;
6496 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6497 perf_sample_regs_user(&data->regs_user, regs,
6498 &data->regs_user_copy);
6500 if (sample_type & PERF_SAMPLE_REGS_USER) {
6501 /* regs dump ABI info */
6502 int size = sizeof(u64);
6504 if (data->regs_user.regs) {
6505 u64 mask = event->attr.sample_regs_user;
6506 size += hweight64(mask) * sizeof(u64);
6509 header->size += size;
6512 if (sample_type & PERF_SAMPLE_STACK_USER) {
6514 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6515 * processed as the last one or have additional check added
6516 * in case new sample type is added, because we could eat
6517 * up the rest of the sample size.
6519 u16 stack_size = event->attr.sample_stack_user;
6520 u16 size = sizeof(u64);
6522 stack_size = perf_sample_ustack_size(stack_size, header->size,
6523 data->regs_user.regs);
6526 * If there is something to dump, add space for the dump
6527 * itself and for the field that tells the dynamic size,
6528 * which is how many have been actually dumped.
6531 size += sizeof(u64) + stack_size;
6533 data->stack_user_size = stack_size;
6534 header->size += size;
6537 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6538 /* regs dump ABI info */
6539 int size = sizeof(u64);
6541 perf_sample_regs_intr(&data->regs_intr, regs);
6543 if (data->regs_intr.regs) {
6544 u64 mask = event->attr.sample_regs_intr;
6546 size += hweight64(mask) * sizeof(u64);
6549 header->size += size;
6552 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6553 data->phys_addr = perf_virt_to_phys(data->addr);
6556 static __always_inline void
6557 __perf_event_output(struct perf_event *event,
6558 struct perf_sample_data *data,
6559 struct pt_regs *regs,
6560 int (*output_begin)(struct perf_output_handle *,
6561 struct perf_event *,
6564 struct perf_output_handle handle;
6565 struct perf_event_header header;
6567 /* protect the callchain buffers */
6570 perf_prepare_sample(&header, data, event, regs);
6572 if (output_begin(&handle, event, header.size))
6575 perf_output_sample(&handle, &header, data, event);
6577 perf_output_end(&handle);
6584 perf_event_output_forward(struct perf_event *event,
6585 struct perf_sample_data *data,
6586 struct pt_regs *regs)
6588 __perf_event_output(event, data, regs, perf_output_begin_forward);
6592 perf_event_output_backward(struct perf_event *event,
6593 struct perf_sample_data *data,
6594 struct pt_regs *regs)
6596 __perf_event_output(event, data, regs, perf_output_begin_backward);
6600 perf_event_output(struct perf_event *event,
6601 struct perf_sample_data *data,
6602 struct pt_regs *regs)
6604 __perf_event_output(event, data, regs, perf_output_begin);
6611 struct perf_read_event {
6612 struct perf_event_header header;
6619 perf_event_read_event(struct perf_event *event,
6620 struct task_struct *task)
6622 struct perf_output_handle handle;
6623 struct perf_sample_data sample;
6624 struct perf_read_event read_event = {
6626 .type = PERF_RECORD_READ,
6628 .size = sizeof(read_event) + event->read_size,
6630 .pid = perf_event_pid(event, task),
6631 .tid = perf_event_tid(event, task),
6635 perf_event_header__init_id(&read_event.header, &sample, event);
6636 ret = perf_output_begin(&handle, event, read_event.header.size);
6640 perf_output_put(&handle, read_event);
6641 perf_output_read(&handle, event);
6642 perf_event__output_id_sample(event, &handle, &sample);
6644 perf_output_end(&handle);
6647 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6650 perf_iterate_ctx(struct perf_event_context *ctx,
6651 perf_iterate_f output,
6652 void *data, bool all)
6654 struct perf_event *event;
6656 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6658 if (event->state < PERF_EVENT_STATE_INACTIVE)
6660 if (!event_filter_match(event))
6664 output(event, data);
6668 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6670 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6671 struct perf_event *event;
6673 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6675 * Skip events that are not fully formed yet; ensure that
6676 * if we observe event->ctx, both event and ctx will be
6677 * complete enough. See perf_install_in_context().
6679 if (!smp_load_acquire(&event->ctx))
6682 if (event->state < PERF_EVENT_STATE_INACTIVE)
6684 if (!event_filter_match(event))
6686 output(event, data);
6691 * Iterate all events that need to receive side-band events.
6693 * For new callers; ensure that account_pmu_sb_event() includes
6694 * your event, otherwise it might not get delivered.
6697 perf_iterate_sb(perf_iterate_f output, void *data,
6698 struct perf_event_context *task_ctx)
6700 struct perf_event_context *ctx;
6707 * If we have task_ctx != NULL we only notify the task context itself.
6708 * The task_ctx is set only for EXIT events before releasing task
6712 perf_iterate_ctx(task_ctx, output, data, false);
6716 perf_iterate_sb_cpu(output, data);
6718 for_each_task_context_nr(ctxn) {
6719 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6721 perf_iterate_ctx(ctx, output, data, false);
6729 * Clear all file-based filters at exec, they'll have to be
6730 * re-instated when/if these objects are mmapped again.
6732 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6734 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6735 struct perf_addr_filter *filter;
6736 unsigned int restart = 0, count = 0;
6737 unsigned long flags;
6739 if (!has_addr_filter(event))
6742 raw_spin_lock_irqsave(&ifh->lock, flags);
6743 list_for_each_entry(filter, &ifh->list, entry) {
6744 if (filter->path.dentry) {
6745 event->addr_filters_offs[count] = 0;
6753 event->addr_filters_gen++;
6754 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6757 perf_event_stop(event, 1);
6760 void perf_event_exec(void)
6762 struct perf_event_context *ctx;
6766 for_each_task_context_nr(ctxn) {
6767 ctx = current->perf_event_ctxp[ctxn];
6771 perf_event_enable_on_exec(ctxn);
6773 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6779 struct remote_output {
6780 struct ring_buffer *rb;
6784 static void __perf_event_output_stop(struct perf_event *event, void *data)
6786 struct perf_event *parent = event->parent;
6787 struct remote_output *ro = data;
6788 struct ring_buffer *rb = ro->rb;
6789 struct stop_event_data sd = {
6793 if (!has_aux(event))
6800 * In case of inheritance, it will be the parent that links to the
6801 * ring-buffer, but it will be the child that's actually using it.
6803 * We are using event::rb to determine if the event should be stopped,
6804 * however this may race with ring_buffer_attach() (through set_output),
6805 * which will make us skip the event that actually needs to be stopped.
6806 * So ring_buffer_attach() has to stop an aux event before re-assigning
6809 if (rcu_dereference(parent->rb) == rb)
6810 ro->err = __perf_event_stop(&sd);
6813 static int __perf_pmu_output_stop(void *info)
6815 struct perf_event *event = info;
6816 struct pmu *pmu = event->pmu;
6817 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6818 struct remote_output ro = {
6823 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6824 if (cpuctx->task_ctx)
6825 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6832 static void perf_pmu_output_stop(struct perf_event *event)
6834 struct perf_event *iter;
6839 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6841 * For per-CPU events, we need to make sure that neither they
6842 * nor their children are running; for cpu==-1 events it's
6843 * sufficient to stop the event itself if it's active, since
6844 * it can't have children.
6848 cpu = READ_ONCE(iter->oncpu);
6853 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6854 if (err == -EAGAIN) {
6863 * task tracking -- fork/exit
6865 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6868 struct perf_task_event {
6869 struct task_struct *task;
6870 struct perf_event_context *task_ctx;
6873 struct perf_event_header header;
6883 static int perf_event_task_match(struct perf_event *event)
6885 return event->attr.comm || event->attr.mmap ||
6886 event->attr.mmap2 || event->attr.mmap_data ||
6890 static void perf_event_task_output(struct perf_event *event,
6893 struct perf_task_event *task_event = data;
6894 struct perf_output_handle handle;
6895 struct perf_sample_data sample;
6896 struct task_struct *task = task_event->task;
6897 int ret, size = task_event->event_id.header.size;
6899 if (!perf_event_task_match(event))
6902 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6904 ret = perf_output_begin(&handle, event,
6905 task_event->event_id.header.size);
6909 task_event->event_id.pid = perf_event_pid(event, task);
6910 task_event->event_id.ppid = perf_event_pid(event, current);
6912 task_event->event_id.tid = perf_event_tid(event, task);
6913 task_event->event_id.ptid = perf_event_tid(event, current);
6915 task_event->event_id.time = perf_event_clock(event);
6917 perf_output_put(&handle, task_event->event_id);
6919 perf_event__output_id_sample(event, &handle, &sample);
6921 perf_output_end(&handle);
6923 task_event->event_id.header.size = size;
6926 static void perf_event_task(struct task_struct *task,
6927 struct perf_event_context *task_ctx,
6930 struct perf_task_event task_event;
6932 if (!atomic_read(&nr_comm_events) &&
6933 !atomic_read(&nr_mmap_events) &&
6934 !atomic_read(&nr_task_events))
6937 task_event = (struct perf_task_event){
6939 .task_ctx = task_ctx,
6942 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6944 .size = sizeof(task_event.event_id),
6954 perf_iterate_sb(perf_event_task_output,
6959 void perf_event_fork(struct task_struct *task)
6961 perf_event_task(task, NULL, 1);
6962 perf_event_namespaces(task);
6969 struct perf_comm_event {
6970 struct task_struct *task;
6975 struct perf_event_header header;
6982 static int perf_event_comm_match(struct perf_event *event)
6984 return event->attr.comm;
6987 static void perf_event_comm_output(struct perf_event *event,
6990 struct perf_comm_event *comm_event = data;
6991 struct perf_output_handle handle;
6992 struct perf_sample_data sample;
6993 int size = comm_event->event_id.header.size;
6996 if (!perf_event_comm_match(event))
6999 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7000 ret = perf_output_begin(&handle, event,
7001 comm_event->event_id.header.size);
7006 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7007 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7009 perf_output_put(&handle, comm_event->event_id);
7010 __output_copy(&handle, comm_event->comm,
7011 comm_event->comm_size);
7013 perf_event__output_id_sample(event, &handle, &sample);
7015 perf_output_end(&handle);
7017 comm_event->event_id.header.size = size;
7020 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7022 char comm[TASK_COMM_LEN];
7025 memset(comm, 0, sizeof(comm));
7026 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7027 size = ALIGN(strlen(comm)+1, sizeof(u64));
7029 comm_event->comm = comm;
7030 comm_event->comm_size = size;
7032 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7034 perf_iterate_sb(perf_event_comm_output,
7039 void perf_event_comm(struct task_struct *task, bool exec)
7041 struct perf_comm_event comm_event;
7043 if (!atomic_read(&nr_comm_events))
7046 comm_event = (struct perf_comm_event){
7052 .type = PERF_RECORD_COMM,
7053 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7061 perf_event_comm_event(&comm_event);
7065 * namespaces tracking
7068 struct perf_namespaces_event {
7069 struct task_struct *task;
7072 struct perf_event_header header;
7077 struct perf_ns_link_info link_info[NR_NAMESPACES];
7081 static int perf_event_namespaces_match(struct perf_event *event)
7083 return event->attr.namespaces;
7086 static void perf_event_namespaces_output(struct perf_event *event,
7089 struct perf_namespaces_event *namespaces_event = data;
7090 struct perf_output_handle handle;
7091 struct perf_sample_data sample;
7092 u16 header_size = namespaces_event->event_id.header.size;
7095 if (!perf_event_namespaces_match(event))
7098 perf_event_header__init_id(&namespaces_event->event_id.header,
7100 ret = perf_output_begin(&handle, event,
7101 namespaces_event->event_id.header.size);
7105 namespaces_event->event_id.pid = perf_event_pid(event,
7106 namespaces_event->task);
7107 namespaces_event->event_id.tid = perf_event_tid(event,
7108 namespaces_event->task);
7110 perf_output_put(&handle, namespaces_event->event_id);
7112 perf_event__output_id_sample(event, &handle, &sample);
7114 perf_output_end(&handle);
7116 namespaces_event->event_id.header.size = header_size;
7119 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7120 struct task_struct *task,
7121 const struct proc_ns_operations *ns_ops)
7123 struct path ns_path;
7124 struct inode *ns_inode;
7127 error = ns_get_path(&ns_path, task, ns_ops);
7129 ns_inode = ns_path.dentry->d_inode;
7130 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7131 ns_link_info->ino = ns_inode->i_ino;
7136 void perf_event_namespaces(struct task_struct *task)
7138 struct perf_namespaces_event namespaces_event;
7139 struct perf_ns_link_info *ns_link_info;
7141 if (!atomic_read(&nr_namespaces_events))
7144 namespaces_event = (struct perf_namespaces_event){
7148 .type = PERF_RECORD_NAMESPACES,
7150 .size = sizeof(namespaces_event.event_id),
7154 .nr_namespaces = NR_NAMESPACES,
7155 /* .link_info[NR_NAMESPACES] */
7159 ns_link_info = namespaces_event.event_id.link_info;
7161 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7162 task, &mntns_operations);
7164 #ifdef CONFIG_USER_NS
7165 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7166 task, &userns_operations);
7168 #ifdef CONFIG_NET_NS
7169 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7170 task, &netns_operations);
7172 #ifdef CONFIG_UTS_NS
7173 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7174 task, &utsns_operations);
7176 #ifdef CONFIG_IPC_NS
7177 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7178 task, &ipcns_operations);
7180 #ifdef CONFIG_PID_NS
7181 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7182 task, &pidns_operations);
7184 #ifdef CONFIG_CGROUPS
7185 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7186 task, &cgroupns_operations);
7189 perf_iterate_sb(perf_event_namespaces_output,
7198 struct perf_mmap_event {
7199 struct vm_area_struct *vma;
7201 const char *file_name;
7209 struct perf_event_header header;
7219 static int perf_event_mmap_match(struct perf_event *event,
7222 struct perf_mmap_event *mmap_event = data;
7223 struct vm_area_struct *vma = mmap_event->vma;
7224 int executable = vma->vm_flags & VM_EXEC;
7226 return (!executable && event->attr.mmap_data) ||
7227 (executable && (event->attr.mmap || event->attr.mmap2));
7230 static void perf_event_mmap_output(struct perf_event *event,
7233 struct perf_mmap_event *mmap_event = data;
7234 struct perf_output_handle handle;
7235 struct perf_sample_data sample;
7236 int size = mmap_event->event_id.header.size;
7237 u32 type = mmap_event->event_id.header.type;
7240 if (!perf_event_mmap_match(event, data))
7243 if (event->attr.mmap2) {
7244 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7245 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7246 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7247 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7248 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7249 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7250 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7253 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7254 ret = perf_output_begin(&handle, event,
7255 mmap_event->event_id.header.size);
7259 mmap_event->event_id.pid = perf_event_pid(event, current);
7260 mmap_event->event_id.tid = perf_event_tid(event, current);
7262 perf_output_put(&handle, mmap_event->event_id);
7264 if (event->attr.mmap2) {
7265 perf_output_put(&handle, mmap_event->maj);
7266 perf_output_put(&handle, mmap_event->min);
7267 perf_output_put(&handle, mmap_event->ino);
7268 perf_output_put(&handle, mmap_event->ino_generation);
7269 perf_output_put(&handle, mmap_event->prot);
7270 perf_output_put(&handle, mmap_event->flags);
7273 __output_copy(&handle, mmap_event->file_name,
7274 mmap_event->file_size);
7276 perf_event__output_id_sample(event, &handle, &sample);
7278 perf_output_end(&handle);
7280 mmap_event->event_id.header.size = size;
7281 mmap_event->event_id.header.type = type;
7284 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7286 struct vm_area_struct *vma = mmap_event->vma;
7287 struct file *file = vma->vm_file;
7288 int maj = 0, min = 0;
7289 u64 ino = 0, gen = 0;
7290 u32 prot = 0, flags = 0;
7296 if (vma->vm_flags & VM_READ)
7298 if (vma->vm_flags & VM_WRITE)
7300 if (vma->vm_flags & VM_EXEC)
7303 if (vma->vm_flags & VM_MAYSHARE)
7306 flags = MAP_PRIVATE;
7308 if (vma->vm_flags & VM_DENYWRITE)
7309 flags |= MAP_DENYWRITE;
7310 if (vma->vm_flags & VM_MAYEXEC)
7311 flags |= MAP_EXECUTABLE;
7312 if (vma->vm_flags & VM_LOCKED)
7313 flags |= MAP_LOCKED;
7314 if (vma->vm_flags & VM_HUGETLB)
7315 flags |= MAP_HUGETLB;
7318 struct inode *inode;
7321 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7327 * d_path() works from the end of the rb backwards, so we
7328 * need to add enough zero bytes after the string to handle
7329 * the 64bit alignment we do later.
7331 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7336 inode = file_inode(vma->vm_file);
7337 dev = inode->i_sb->s_dev;
7339 gen = inode->i_generation;
7345 if (vma->vm_ops && vma->vm_ops->name) {
7346 name = (char *) vma->vm_ops->name(vma);
7351 name = (char *)arch_vma_name(vma);
7355 if (vma->vm_start <= vma->vm_mm->start_brk &&
7356 vma->vm_end >= vma->vm_mm->brk) {
7360 if (vma->vm_start <= vma->vm_mm->start_stack &&
7361 vma->vm_end >= vma->vm_mm->start_stack) {
7371 strlcpy(tmp, name, sizeof(tmp));
7375 * Since our buffer works in 8 byte units we need to align our string
7376 * size to a multiple of 8. However, we must guarantee the tail end is
7377 * zero'd out to avoid leaking random bits to userspace.
7379 size = strlen(name)+1;
7380 while (!IS_ALIGNED(size, sizeof(u64)))
7381 name[size++] = '\0';
7383 mmap_event->file_name = name;
7384 mmap_event->file_size = size;
7385 mmap_event->maj = maj;
7386 mmap_event->min = min;
7387 mmap_event->ino = ino;
7388 mmap_event->ino_generation = gen;
7389 mmap_event->prot = prot;
7390 mmap_event->flags = flags;
7392 if (!(vma->vm_flags & VM_EXEC))
7393 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7395 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7397 perf_iterate_sb(perf_event_mmap_output,
7405 * Check whether inode and address range match filter criteria.
7407 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7408 struct file *file, unsigned long offset,
7411 /* d_inode(NULL) won't be equal to any mapped user-space file */
7412 if (!filter->path.dentry)
7415 if (d_inode(filter->path.dentry) != file_inode(file))
7418 if (filter->offset > offset + size)
7421 if (filter->offset + filter->size < offset)
7427 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7429 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7430 struct vm_area_struct *vma = data;
7431 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7432 struct file *file = vma->vm_file;
7433 struct perf_addr_filter *filter;
7434 unsigned int restart = 0, count = 0;
7436 if (!has_addr_filter(event))
7442 raw_spin_lock_irqsave(&ifh->lock, flags);
7443 list_for_each_entry(filter, &ifh->list, entry) {
7444 if (perf_addr_filter_match(filter, file, off,
7445 vma->vm_end - vma->vm_start)) {
7446 event->addr_filters_offs[count] = vma->vm_start;
7454 event->addr_filters_gen++;
7455 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7458 perf_event_stop(event, 1);
7462 * Adjust all task's events' filters to the new vma
7464 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7466 struct perf_event_context *ctx;
7470 * Data tracing isn't supported yet and as such there is no need
7471 * to keep track of anything that isn't related to executable code:
7473 if (!(vma->vm_flags & VM_EXEC))
7477 for_each_task_context_nr(ctxn) {
7478 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7482 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7487 void perf_event_mmap(struct vm_area_struct *vma)
7489 struct perf_mmap_event mmap_event;
7491 if (!atomic_read(&nr_mmap_events))
7494 mmap_event = (struct perf_mmap_event){
7500 .type = PERF_RECORD_MMAP,
7501 .misc = PERF_RECORD_MISC_USER,
7506 .start = vma->vm_start,
7507 .len = vma->vm_end - vma->vm_start,
7508 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7510 /* .maj (attr_mmap2 only) */
7511 /* .min (attr_mmap2 only) */
7512 /* .ino (attr_mmap2 only) */
7513 /* .ino_generation (attr_mmap2 only) */
7514 /* .prot (attr_mmap2 only) */
7515 /* .flags (attr_mmap2 only) */
7518 perf_addr_filters_adjust(vma);
7519 perf_event_mmap_event(&mmap_event);
7522 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7523 unsigned long size, u64 flags)
7525 struct perf_output_handle handle;
7526 struct perf_sample_data sample;
7527 struct perf_aux_event {
7528 struct perf_event_header header;
7534 .type = PERF_RECORD_AUX,
7536 .size = sizeof(rec),
7544 perf_event_header__init_id(&rec.header, &sample, event);
7545 ret = perf_output_begin(&handle, event, rec.header.size);
7550 perf_output_put(&handle, rec);
7551 perf_event__output_id_sample(event, &handle, &sample);
7553 perf_output_end(&handle);
7557 * Lost/dropped samples logging
7559 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7561 struct perf_output_handle handle;
7562 struct perf_sample_data sample;
7566 struct perf_event_header header;
7568 } lost_samples_event = {
7570 .type = PERF_RECORD_LOST_SAMPLES,
7572 .size = sizeof(lost_samples_event),
7577 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7579 ret = perf_output_begin(&handle, event,
7580 lost_samples_event.header.size);
7584 perf_output_put(&handle, lost_samples_event);
7585 perf_event__output_id_sample(event, &handle, &sample);
7586 perf_output_end(&handle);
7590 * context_switch tracking
7593 struct perf_switch_event {
7594 struct task_struct *task;
7595 struct task_struct *next_prev;
7598 struct perf_event_header header;
7604 static int perf_event_switch_match(struct perf_event *event)
7606 return event->attr.context_switch;
7609 static void perf_event_switch_output(struct perf_event *event, void *data)
7611 struct perf_switch_event *se = data;
7612 struct perf_output_handle handle;
7613 struct perf_sample_data sample;
7616 if (!perf_event_switch_match(event))
7619 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7620 if (event->ctx->task) {
7621 se->event_id.header.type = PERF_RECORD_SWITCH;
7622 se->event_id.header.size = sizeof(se->event_id.header);
7624 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7625 se->event_id.header.size = sizeof(se->event_id);
7626 se->event_id.next_prev_pid =
7627 perf_event_pid(event, se->next_prev);
7628 se->event_id.next_prev_tid =
7629 perf_event_tid(event, se->next_prev);
7632 perf_event_header__init_id(&se->event_id.header, &sample, event);
7634 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7638 if (event->ctx->task)
7639 perf_output_put(&handle, se->event_id.header);
7641 perf_output_put(&handle, se->event_id);
7643 perf_event__output_id_sample(event, &handle, &sample);
7645 perf_output_end(&handle);
7648 static void perf_event_switch(struct task_struct *task,
7649 struct task_struct *next_prev, bool sched_in)
7651 struct perf_switch_event switch_event;
7653 /* N.B. caller checks nr_switch_events != 0 */
7655 switch_event = (struct perf_switch_event){
7657 .next_prev = next_prev,
7661 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7664 /* .next_prev_pid */
7665 /* .next_prev_tid */
7669 if (!sched_in && task->state == TASK_RUNNING)
7670 switch_event.event_id.header.misc |=
7671 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7673 perf_iterate_sb(perf_event_switch_output,
7679 * IRQ throttle logging
7682 static void perf_log_throttle(struct perf_event *event, int enable)
7684 struct perf_output_handle handle;
7685 struct perf_sample_data sample;
7689 struct perf_event_header header;
7693 } throttle_event = {
7695 .type = PERF_RECORD_THROTTLE,
7697 .size = sizeof(throttle_event),
7699 .time = perf_event_clock(event),
7700 .id = primary_event_id(event),
7701 .stream_id = event->id,
7705 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7707 perf_event_header__init_id(&throttle_event.header, &sample, event);
7709 ret = perf_output_begin(&handle, event,
7710 throttle_event.header.size);
7714 perf_output_put(&handle, throttle_event);
7715 perf_event__output_id_sample(event, &handle, &sample);
7716 perf_output_end(&handle);
7719 void perf_event_itrace_started(struct perf_event *event)
7721 event->attach_state |= PERF_ATTACH_ITRACE;
7724 static void perf_log_itrace_start(struct perf_event *event)
7726 struct perf_output_handle handle;
7727 struct perf_sample_data sample;
7728 struct perf_aux_event {
7729 struct perf_event_header header;
7736 event = event->parent;
7738 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7739 event->attach_state & PERF_ATTACH_ITRACE)
7742 rec.header.type = PERF_RECORD_ITRACE_START;
7743 rec.header.misc = 0;
7744 rec.header.size = sizeof(rec);
7745 rec.pid = perf_event_pid(event, current);
7746 rec.tid = perf_event_tid(event, current);
7748 perf_event_header__init_id(&rec.header, &sample, event);
7749 ret = perf_output_begin(&handle, event, rec.header.size);
7754 perf_output_put(&handle, rec);
7755 perf_event__output_id_sample(event, &handle, &sample);
7757 perf_output_end(&handle);
7761 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7763 struct hw_perf_event *hwc = &event->hw;
7767 seq = __this_cpu_read(perf_throttled_seq);
7768 if (seq != hwc->interrupts_seq) {
7769 hwc->interrupts_seq = seq;
7770 hwc->interrupts = 1;
7773 if (unlikely(throttle
7774 && hwc->interrupts >= max_samples_per_tick)) {
7775 __this_cpu_inc(perf_throttled_count);
7776 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7777 hwc->interrupts = MAX_INTERRUPTS;
7778 perf_log_throttle(event, 0);
7783 if (event->attr.freq) {
7784 u64 now = perf_clock();
7785 s64 delta = now - hwc->freq_time_stamp;
7787 hwc->freq_time_stamp = now;
7789 if (delta > 0 && delta < 2*TICK_NSEC)
7790 perf_adjust_period(event, delta, hwc->last_period, true);
7796 int perf_event_account_interrupt(struct perf_event *event)
7798 return __perf_event_account_interrupt(event, 1);
7802 * Generic event overflow handling, sampling.
7805 static int __perf_event_overflow(struct perf_event *event,
7806 int throttle, struct perf_sample_data *data,
7807 struct pt_regs *regs)
7809 int events = atomic_read(&event->event_limit);
7813 * Non-sampling counters might still use the PMI to fold short
7814 * hardware counters, ignore those.
7816 if (unlikely(!is_sampling_event(event)))
7819 ret = __perf_event_account_interrupt(event, throttle);
7822 * XXX event_limit might not quite work as expected on inherited
7826 event->pending_kill = POLL_IN;
7827 if (events && atomic_dec_and_test(&event->event_limit)) {
7829 event->pending_kill = POLL_HUP;
7831 perf_event_disable_inatomic(event);
7834 READ_ONCE(event->overflow_handler)(event, data, regs);
7836 if (*perf_event_fasync(event) && event->pending_kill) {
7837 event->pending_wakeup = 1;
7838 irq_work_queue(&event->pending);
7844 int perf_event_overflow(struct perf_event *event,
7845 struct perf_sample_data *data,
7846 struct pt_regs *regs)
7848 return __perf_event_overflow(event, 1, data, regs);
7852 * Generic software event infrastructure
7855 struct swevent_htable {
7856 struct swevent_hlist *swevent_hlist;
7857 struct mutex hlist_mutex;
7860 /* Recursion avoidance in each contexts */
7861 int recursion[PERF_NR_CONTEXTS];
7864 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7867 * We directly increment event->count and keep a second value in
7868 * event->hw.period_left to count intervals. This period event
7869 * is kept in the range [-sample_period, 0] so that we can use the
7873 u64 perf_swevent_set_period(struct perf_event *event)
7875 struct hw_perf_event *hwc = &event->hw;
7876 u64 period = hwc->last_period;
7880 hwc->last_period = hwc->sample_period;
7883 old = val = local64_read(&hwc->period_left);
7887 nr = div64_u64(period + val, period);
7888 offset = nr * period;
7890 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7896 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7897 struct perf_sample_data *data,
7898 struct pt_regs *regs)
7900 struct hw_perf_event *hwc = &event->hw;
7904 overflow = perf_swevent_set_period(event);
7906 if (hwc->interrupts == MAX_INTERRUPTS)
7909 for (; overflow; overflow--) {
7910 if (__perf_event_overflow(event, throttle,
7913 * We inhibit the overflow from happening when
7914 * hwc->interrupts == MAX_INTERRUPTS.
7922 static void perf_swevent_event(struct perf_event *event, u64 nr,
7923 struct perf_sample_data *data,
7924 struct pt_regs *regs)
7926 struct hw_perf_event *hwc = &event->hw;
7928 local64_add(nr, &event->count);
7933 if (!is_sampling_event(event))
7936 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7938 return perf_swevent_overflow(event, 1, data, regs);
7940 data->period = event->hw.last_period;
7942 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7943 return perf_swevent_overflow(event, 1, data, regs);
7945 if (local64_add_negative(nr, &hwc->period_left))
7948 perf_swevent_overflow(event, 0, data, regs);
7951 static int perf_exclude_event(struct perf_event *event,
7952 struct pt_regs *regs)
7954 if (event->hw.state & PERF_HES_STOPPED)
7958 if (event->attr.exclude_user && user_mode(regs))
7961 if (event->attr.exclude_kernel && !user_mode(regs))
7968 static int perf_swevent_match(struct perf_event *event,
7969 enum perf_type_id type,
7971 struct perf_sample_data *data,
7972 struct pt_regs *regs)
7974 if (event->attr.type != type)
7977 if (event->attr.config != event_id)
7980 if (perf_exclude_event(event, regs))
7986 static inline u64 swevent_hash(u64 type, u32 event_id)
7988 u64 val = event_id | (type << 32);
7990 return hash_64(val, SWEVENT_HLIST_BITS);
7993 static inline struct hlist_head *
7994 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7996 u64 hash = swevent_hash(type, event_id);
7998 return &hlist->heads[hash];
8001 /* For the read side: events when they trigger */
8002 static inline struct hlist_head *
8003 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8005 struct swevent_hlist *hlist;
8007 hlist = rcu_dereference(swhash->swevent_hlist);
8011 return __find_swevent_head(hlist, type, event_id);
8014 /* For the event head insertion and removal in the hlist */
8015 static inline struct hlist_head *
8016 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8018 struct swevent_hlist *hlist;
8019 u32 event_id = event->attr.config;
8020 u64 type = event->attr.type;
8023 * Event scheduling is always serialized against hlist allocation
8024 * and release. Which makes the protected version suitable here.
8025 * The context lock guarantees that.
8027 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8028 lockdep_is_held(&event->ctx->lock));
8032 return __find_swevent_head(hlist, type, event_id);
8035 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8037 struct perf_sample_data *data,
8038 struct pt_regs *regs)
8040 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8041 struct perf_event *event;
8042 struct hlist_head *head;
8045 head = find_swevent_head_rcu(swhash, type, event_id);
8049 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8050 if (perf_swevent_match(event, type, event_id, data, regs))
8051 perf_swevent_event(event, nr, data, regs);
8057 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8059 int perf_swevent_get_recursion_context(void)
8061 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8063 return get_recursion_context(swhash->recursion);
8065 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8067 void perf_swevent_put_recursion_context(int rctx)
8069 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8071 put_recursion_context(swhash->recursion, rctx);
8074 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8076 struct perf_sample_data data;
8078 if (WARN_ON_ONCE(!regs))
8081 perf_sample_data_init(&data, addr, 0);
8082 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8085 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8089 preempt_disable_notrace();
8090 rctx = perf_swevent_get_recursion_context();
8091 if (unlikely(rctx < 0))
8094 ___perf_sw_event(event_id, nr, regs, addr);
8096 perf_swevent_put_recursion_context(rctx);
8098 preempt_enable_notrace();
8101 static void perf_swevent_read(struct perf_event *event)
8105 static int perf_swevent_add(struct perf_event *event, int flags)
8107 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8108 struct hw_perf_event *hwc = &event->hw;
8109 struct hlist_head *head;
8111 if (is_sampling_event(event)) {
8112 hwc->last_period = hwc->sample_period;
8113 perf_swevent_set_period(event);
8116 hwc->state = !(flags & PERF_EF_START);
8118 head = find_swevent_head(swhash, event);
8119 if (WARN_ON_ONCE(!head))
8122 hlist_add_head_rcu(&event->hlist_entry, head);
8123 perf_event_update_userpage(event);
8128 static void perf_swevent_del(struct perf_event *event, int flags)
8130 hlist_del_rcu(&event->hlist_entry);
8133 static void perf_swevent_start(struct perf_event *event, int flags)
8135 event->hw.state = 0;
8138 static void perf_swevent_stop(struct perf_event *event, int flags)
8140 event->hw.state = PERF_HES_STOPPED;
8143 /* Deref the hlist from the update side */
8144 static inline struct swevent_hlist *
8145 swevent_hlist_deref(struct swevent_htable *swhash)
8147 return rcu_dereference_protected(swhash->swevent_hlist,
8148 lockdep_is_held(&swhash->hlist_mutex));
8151 static void swevent_hlist_release(struct swevent_htable *swhash)
8153 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8158 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8159 kfree_rcu(hlist, rcu_head);
8162 static void swevent_hlist_put_cpu(int cpu)
8164 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8166 mutex_lock(&swhash->hlist_mutex);
8168 if (!--swhash->hlist_refcount)
8169 swevent_hlist_release(swhash);
8171 mutex_unlock(&swhash->hlist_mutex);
8174 static void swevent_hlist_put(void)
8178 for_each_possible_cpu(cpu)
8179 swevent_hlist_put_cpu(cpu);
8182 static int swevent_hlist_get_cpu(int cpu)
8184 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8187 mutex_lock(&swhash->hlist_mutex);
8188 if (!swevent_hlist_deref(swhash) &&
8189 cpumask_test_cpu(cpu, perf_online_mask)) {
8190 struct swevent_hlist *hlist;
8192 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8197 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8199 swhash->hlist_refcount++;
8201 mutex_unlock(&swhash->hlist_mutex);
8206 static int swevent_hlist_get(void)
8208 int err, cpu, failed_cpu;
8210 mutex_lock(&pmus_lock);
8211 for_each_possible_cpu(cpu) {
8212 err = swevent_hlist_get_cpu(cpu);
8218 mutex_unlock(&pmus_lock);
8221 for_each_possible_cpu(cpu) {
8222 if (cpu == failed_cpu)
8224 swevent_hlist_put_cpu(cpu);
8226 mutex_unlock(&pmus_lock);
8230 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8232 static void sw_perf_event_destroy(struct perf_event *event)
8234 u64 event_id = event->attr.config;
8236 WARN_ON(event->parent);
8238 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8239 swevent_hlist_put();
8242 static int perf_swevent_init(struct perf_event *event)
8244 u64 event_id = event->attr.config;
8246 if (event->attr.type != PERF_TYPE_SOFTWARE)
8250 * no branch sampling for software events
8252 if (has_branch_stack(event))
8256 case PERF_COUNT_SW_CPU_CLOCK:
8257 case PERF_COUNT_SW_TASK_CLOCK:
8264 if (event_id >= PERF_COUNT_SW_MAX)
8267 if (!event->parent) {
8270 err = swevent_hlist_get();
8274 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8275 event->destroy = sw_perf_event_destroy;
8281 static struct pmu perf_swevent = {
8282 .task_ctx_nr = perf_sw_context,
8284 .capabilities = PERF_PMU_CAP_NO_NMI,
8286 .event_init = perf_swevent_init,
8287 .add = perf_swevent_add,
8288 .del = perf_swevent_del,
8289 .start = perf_swevent_start,
8290 .stop = perf_swevent_stop,
8291 .read = perf_swevent_read,
8294 #ifdef CONFIG_EVENT_TRACING
8296 static int perf_tp_filter_match(struct perf_event *event,
8297 struct perf_sample_data *data)
8299 void *record = data->raw->frag.data;
8301 /* only top level events have filters set */
8303 event = event->parent;
8305 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8310 static int perf_tp_event_match(struct perf_event *event,
8311 struct perf_sample_data *data,
8312 struct pt_regs *regs)
8314 if (event->hw.state & PERF_HES_STOPPED)
8317 * All tracepoints are from kernel-space.
8319 if (event->attr.exclude_kernel)
8322 if (!perf_tp_filter_match(event, data))
8328 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8329 struct trace_event_call *call, u64 count,
8330 struct pt_regs *regs, struct hlist_head *head,
8331 struct task_struct *task)
8333 if (bpf_prog_array_valid(call)) {
8334 *(struct pt_regs **)raw_data = regs;
8335 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8336 perf_swevent_put_recursion_context(rctx);
8340 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8343 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8345 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8346 struct pt_regs *regs, struct hlist_head *head, int rctx,
8347 struct task_struct *task)
8349 struct perf_sample_data data;
8350 struct perf_event *event;
8352 struct perf_raw_record raw = {
8359 perf_sample_data_init(&data, 0, 0);
8362 perf_trace_buf_update(record, event_type);
8364 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8365 if (perf_tp_event_match(event, &data, regs))
8366 perf_swevent_event(event, count, &data, regs);
8370 * If we got specified a target task, also iterate its context and
8371 * deliver this event there too.
8373 if (task && task != current) {
8374 struct perf_event_context *ctx;
8375 struct trace_entry *entry = record;
8378 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8382 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8383 if (event->cpu != smp_processor_id())
8385 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8387 if (event->attr.config != entry->type)
8389 if (perf_tp_event_match(event, &data, regs))
8390 perf_swevent_event(event, count, &data, regs);
8396 perf_swevent_put_recursion_context(rctx);
8398 EXPORT_SYMBOL_GPL(perf_tp_event);
8400 static void tp_perf_event_destroy(struct perf_event *event)
8402 perf_trace_destroy(event);
8405 static int perf_tp_event_init(struct perf_event *event)
8409 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8413 * no branch sampling for tracepoint events
8415 if (has_branch_stack(event))
8418 err = perf_trace_init(event);
8422 event->destroy = tp_perf_event_destroy;
8427 static struct pmu perf_tracepoint = {
8428 .task_ctx_nr = perf_sw_context,
8430 .event_init = perf_tp_event_init,
8431 .add = perf_trace_add,
8432 .del = perf_trace_del,
8433 .start = perf_swevent_start,
8434 .stop = perf_swevent_stop,
8435 .read = perf_swevent_read,
8438 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8440 * Flags in config, used by dynamic PMU kprobe and uprobe
8441 * The flags should match following PMU_FORMAT_ATTR().
8443 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8444 * if not set, create kprobe/uprobe
8446 enum perf_probe_config {
8447 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8450 PMU_FORMAT_ATTR(retprobe, "config:0");
8452 static struct attribute *probe_attrs[] = {
8453 &format_attr_retprobe.attr,
8457 static struct attribute_group probe_format_group = {
8459 .attrs = probe_attrs,
8462 static const struct attribute_group *probe_attr_groups[] = {
8463 &probe_format_group,
8468 #ifdef CONFIG_KPROBE_EVENTS
8469 static int perf_kprobe_event_init(struct perf_event *event);
8470 static struct pmu perf_kprobe = {
8471 .task_ctx_nr = perf_sw_context,
8472 .event_init = perf_kprobe_event_init,
8473 .add = perf_trace_add,
8474 .del = perf_trace_del,
8475 .start = perf_swevent_start,
8476 .stop = perf_swevent_stop,
8477 .read = perf_swevent_read,
8478 .attr_groups = probe_attr_groups,
8481 static int perf_kprobe_event_init(struct perf_event *event)
8486 if (event->attr.type != perf_kprobe.type)
8489 if (!capable(CAP_SYS_ADMIN))
8493 * no branch sampling for probe events
8495 if (has_branch_stack(event))
8498 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8499 err = perf_kprobe_init(event, is_retprobe);
8503 event->destroy = perf_kprobe_destroy;
8507 #endif /* CONFIG_KPROBE_EVENTS */
8509 #ifdef CONFIG_UPROBE_EVENTS
8510 static int perf_uprobe_event_init(struct perf_event *event);
8511 static struct pmu perf_uprobe = {
8512 .task_ctx_nr = perf_sw_context,
8513 .event_init = perf_uprobe_event_init,
8514 .add = perf_trace_add,
8515 .del = perf_trace_del,
8516 .start = perf_swevent_start,
8517 .stop = perf_swevent_stop,
8518 .read = perf_swevent_read,
8519 .attr_groups = probe_attr_groups,
8522 static int perf_uprobe_event_init(struct perf_event *event)
8527 if (event->attr.type != perf_uprobe.type)
8530 if (!capable(CAP_SYS_ADMIN))
8534 * no branch sampling for probe events
8536 if (has_branch_stack(event))
8539 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8540 err = perf_uprobe_init(event, is_retprobe);
8544 event->destroy = perf_uprobe_destroy;
8548 #endif /* CONFIG_UPROBE_EVENTS */
8550 static inline void perf_tp_register(void)
8552 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8553 #ifdef CONFIG_KPROBE_EVENTS
8554 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8556 #ifdef CONFIG_UPROBE_EVENTS
8557 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8561 static void perf_event_free_filter(struct perf_event *event)
8563 ftrace_profile_free_filter(event);
8566 #ifdef CONFIG_BPF_SYSCALL
8567 static void bpf_overflow_handler(struct perf_event *event,
8568 struct perf_sample_data *data,
8569 struct pt_regs *regs)
8571 struct bpf_perf_event_data_kern ctx = {
8577 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8579 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8582 ret = BPF_PROG_RUN(event->prog, &ctx);
8585 __this_cpu_dec(bpf_prog_active);
8590 event->orig_overflow_handler(event, data, regs);
8593 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8595 struct bpf_prog *prog;
8597 if (event->overflow_handler_context)
8598 /* hw breakpoint or kernel counter */
8604 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8606 return PTR_ERR(prog);
8609 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8610 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8614 static void perf_event_free_bpf_handler(struct perf_event *event)
8616 struct bpf_prog *prog = event->prog;
8621 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8626 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8630 static void perf_event_free_bpf_handler(struct perf_event *event)
8636 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8637 * with perf_event_open()
8639 static inline bool perf_event_is_tracing(struct perf_event *event)
8641 if (event->pmu == &perf_tracepoint)
8643 #ifdef CONFIG_KPROBE_EVENTS
8644 if (event->pmu == &perf_kprobe)
8647 #ifdef CONFIG_UPROBE_EVENTS
8648 if (event->pmu == &perf_uprobe)
8654 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8656 bool is_kprobe, is_tracepoint, is_syscall_tp;
8657 struct bpf_prog *prog;
8660 if (!perf_event_is_tracing(event))
8661 return perf_event_set_bpf_handler(event, prog_fd);
8663 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8664 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8665 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8666 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8667 /* bpf programs can only be attached to u/kprobe or tracepoint */
8670 prog = bpf_prog_get(prog_fd);
8672 return PTR_ERR(prog);
8674 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8675 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8676 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8677 /* valid fd, but invalid bpf program type */
8682 /* Kprobe override only works for kprobes, not uprobes. */
8683 if (prog->kprobe_override &&
8684 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8689 if (is_tracepoint || is_syscall_tp) {
8690 int off = trace_event_get_offsets(event->tp_event);
8692 if (prog->aux->max_ctx_offset > off) {
8698 ret = perf_event_attach_bpf_prog(event, prog);
8704 static void perf_event_free_bpf_prog(struct perf_event *event)
8706 if (!perf_event_is_tracing(event)) {
8707 perf_event_free_bpf_handler(event);
8710 perf_event_detach_bpf_prog(event);
8715 static inline void perf_tp_register(void)
8719 static void perf_event_free_filter(struct perf_event *event)
8723 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8728 static void perf_event_free_bpf_prog(struct perf_event *event)
8731 #endif /* CONFIG_EVENT_TRACING */
8733 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8734 void perf_bp_event(struct perf_event *bp, void *data)
8736 struct perf_sample_data sample;
8737 struct pt_regs *regs = data;
8739 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8741 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8742 perf_swevent_event(bp, 1, &sample, regs);
8747 * Allocate a new address filter
8749 static struct perf_addr_filter *
8750 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8752 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8753 struct perf_addr_filter *filter;
8755 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8759 INIT_LIST_HEAD(&filter->entry);
8760 list_add_tail(&filter->entry, filters);
8765 static void free_filters_list(struct list_head *filters)
8767 struct perf_addr_filter *filter, *iter;
8769 list_for_each_entry_safe(filter, iter, filters, entry) {
8770 path_put(&filter->path);
8771 list_del(&filter->entry);
8777 * Free existing address filters and optionally install new ones
8779 static void perf_addr_filters_splice(struct perf_event *event,
8780 struct list_head *head)
8782 unsigned long flags;
8785 if (!has_addr_filter(event))
8788 /* don't bother with children, they don't have their own filters */
8792 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8794 list_splice_init(&event->addr_filters.list, &list);
8796 list_splice(head, &event->addr_filters.list);
8798 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8800 free_filters_list(&list);
8804 * Scan through mm's vmas and see if one of them matches the
8805 * @filter; if so, adjust filter's address range.
8806 * Called with mm::mmap_sem down for reading.
8808 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8809 struct mm_struct *mm)
8811 struct vm_area_struct *vma;
8813 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8814 struct file *file = vma->vm_file;
8815 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8816 unsigned long vma_size = vma->vm_end - vma->vm_start;
8821 if (!perf_addr_filter_match(filter, file, off, vma_size))
8824 return vma->vm_start;
8831 * Update event's address range filters based on the
8832 * task's existing mappings, if any.
8834 static void perf_event_addr_filters_apply(struct perf_event *event)
8836 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8837 struct task_struct *task = READ_ONCE(event->ctx->task);
8838 struct perf_addr_filter *filter;
8839 struct mm_struct *mm = NULL;
8840 unsigned int count = 0;
8841 unsigned long flags;
8844 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8845 * will stop on the parent's child_mutex that our caller is also holding
8847 if (task == TASK_TOMBSTONE)
8850 if (!ifh->nr_file_filters)
8853 mm = get_task_mm(event->ctx->task);
8857 down_read(&mm->mmap_sem);
8859 raw_spin_lock_irqsave(&ifh->lock, flags);
8860 list_for_each_entry(filter, &ifh->list, entry) {
8861 event->addr_filters_offs[count] = 0;
8864 * Adjust base offset if the filter is associated to a binary
8865 * that needs to be mapped:
8867 if (filter->path.dentry)
8868 event->addr_filters_offs[count] =
8869 perf_addr_filter_apply(filter, mm);
8874 event->addr_filters_gen++;
8875 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8877 up_read(&mm->mmap_sem);
8882 perf_event_stop(event, 1);
8886 * Address range filtering: limiting the data to certain
8887 * instruction address ranges. Filters are ioctl()ed to us from
8888 * userspace as ascii strings.
8890 * Filter string format:
8893 * where ACTION is one of the
8894 * * "filter": limit the trace to this region
8895 * * "start": start tracing from this address
8896 * * "stop": stop tracing at this address/region;
8898 * * for kernel addresses: <start address>[/<size>]
8899 * * for object files: <start address>[/<size>]@</path/to/object/file>
8901 * if <size> is not specified or is zero, the range is treated as a single
8902 * address; not valid for ACTION=="filter".
8916 IF_STATE_ACTION = 0,
8921 static const match_table_t if_tokens = {
8922 { IF_ACT_FILTER, "filter" },
8923 { IF_ACT_START, "start" },
8924 { IF_ACT_STOP, "stop" },
8925 { IF_SRC_FILE, "%u/%u@%s" },
8926 { IF_SRC_KERNEL, "%u/%u" },
8927 { IF_SRC_FILEADDR, "%u@%s" },
8928 { IF_SRC_KERNELADDR, "%u" },
8929 { IF_ACT_NONE, NULL },
8933 * Address filter string parser
8936 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8937 struct list_head *filters)
8939 struct perf_addr_filter *filter = NULL;
8940 char *start, *orig, *filename = NULL;
8941 substring_t args[MAX_OPT_ARGS];
8942 int state = IF_STATE_ACTION, token;
8943 unsigned int kernel = 0;
8946 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8950 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8951 static const enum perf_addr_filter_action_t actions[] = {
8952 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
8953 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
8954 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
8961 /* filter definition begins */
8962 if (state == IF_STATE_ACTION) {
8963 filter = perf_addr_filter_new(event, filters);
8968 token = match_token(start, if_tokens, args);
8973 if (state != IF_STATE_ACTION)
8976 filter->action = actions[token];
8977 state = IF_STATE_SOURCE;
8980 case IF_SRC_KERNELADDR:
8984 case IF_SRC_FILEADDR:
8986 if (state != IF_STATE_SOURCE)
8990 ret = kstrtoul(args[0].from, 0, &filter->offset);
8994 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
8996 ret = kstrtoul(args[1].from, 0, &filter->size);
9001 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9002 int fpos = token == IF_SRC_FILE ? 2 : 1;
9004 filename = match_strdup(&args[fpos]);
9011 state = IF_STATE_END;
9019 * Filter definition is fully parsed, validate and install it.
9020 * Make sure that it doesn't contradict itself or the event's
9023 if (state == IF_STATE_END) {
9025 if (kernel && event->attr.exclude_kernel)
9029 * ACTION "filter" must have a non-zero length region
9032 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9041 * For now, we only support file-based filters
9042 * in per-task events; doing so for CPU-wide
9043 * events requires additional context switching
9044 * trickery, since same object code will be
9045 * mapped at different virtual addresses in
9046 * different processes.
9049 if (!event->ctx->task)
9050 goto fail_free_name;
9052 /* look up the path and grab its inode */
9053 ret = kern_path(filename, LOOKUP_FOLLOW,
9056 goto fail_free_name;
9062 if (!filter->path.dentry ||
9063 !S_ISREG(d_inode(filter->path.dentry)
9067 event->addr_filters.nr_file_filters++;
9070 /* ready to consume more filters */
9071 state = IF_STATE_ACTION;
9076 if (state != IF_STATE_ACTION)
9086 free_filters_list(filters);
9093 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9099 * Since this is called in perf_ioctl() path, we're already holding
9102 lockdep_assert_held(&event->ctx->mutex);
9104 if (WARN_ON_ONCE(event->parent))
9107 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9109 goto fail_clear_files;
9111 ret = event->pmu->addr_filters_validate(&filters);
9113 goto fail_free_filters;
9115 /* remove existing filters, if any */
9116 perf_addr_filters_splice(event, &filters);
9118 /* install new filters */
9119 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9124 free_filters_list(&filters);
9127 event->addr_filters.nr_file_filters = 0;
9132 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9137 filter_str = strndup_user(arg, PAGE_SIZE);
9138 if (IS_ERR(filter_str))
9139 return PTR_ERR(filter_str);
9141 #ifdef CONFIG_EVENT_TRACING
9142 if (perf_event_is_tracing(event)) {
9143 struct perf_event_context *ctx = event->ctx;
9146 * Beware, here be dragons!!
9148 * the tracepoint muck will deadlock against ctx->mutex, but
9149 * the tracepoint stuff does not actually need it. So
9150 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9151 * already have a reference on ctx.
9153 * This can result in event getting moved to a different ctx,
9154 * but that does not affect the tracepoint state.
9156 mutex_unlock(&ctx->mutex);
9157 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9158 mutex_lock(&ctx->mutex);
9161 if (has_addr_filter(event))
9162 ret = perf_event_set_addr_filter(event, filter_str);
9169 * hrtimer based swevent callback
9172 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9174 enum hrtimer_restart ret = HRTIMER_RESTART;
9175 struct perf_sample_data data;
9176 struct pt_regs *regs;
9177 struct perf_event *event;
9180 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9182 if (event->state != PERF_EVENT_STATE_ACTIVE)
9183 return HRTIMER_NORESTART;
9185 event->pmu->read(event);
9187 perf_sample_data_init(&data, 0, event->hw.last_period);
9188 regs = get_irq_regs();
9190 if (regs && !perf_exclude_event(event, regs)) {
9191 if (!(event->attr.exclude_idle && is_idle_task(current)))
9192 if (__perf_event_overflow(event, 1, &data, regs))
9193 ret = HRTIMER_NORESTART;
9196 period = max_t(u64, 10000, event->hw.sample_period);
9197 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9202 static void perf_swevent_start_hrtimer(struct perf_event *event)
9204 struct hw_perf_event *hwc = &event->hw;
9207 if (!is_sampling_event(event))
9210 period = local64_read(&hwc->period_left);
9215 local64_set(&hwc->period_left, 0);
9217 period = max_t(u64, 10000, hwc->sample_period);
9219 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9220 HRTIMER_MODE_REL_PINNED);
9223 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9225 struct hw_perf_event *hwc = &event->hw;
9227 if (is_sampling_event(event)) {
9228 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9229 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9231 hrtimer_cancel(&hwc->hrtimer);
9235 static void perf_swevent_init_hrtimer(struct perf_event *event)
9237 struct hw_perf_event *hwc = &event->hw;
9239 if (!is_sampling_event(event))
9242 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9243 hwc->hrtimer.function = perf_swevent_hrtimer;
9246 * Since hrtimers have a fixed rate, we can do a static freq->period
9247 * mapping and avoid the whole period adjust feedback stuff.
9249 if (event->attr.freq) {
9250 long freq = event->attr.sample_freq;
9252 event->attr.sample_period = NSEC_PER_SEC / freq;
9253 hwc->sample_period = event->attr.sample_period;
9254 local64_set(&hwc->period_left, hwc->sample_period);
9255 hwc->last_period = hwc->sample_period;
9256 event->attr.freq = 0;
9261 * Software event: cpu wall time clock
9264 static void cpu_clock_event_update(struct perf_event *event)
9269 now = local_clock();
9270 prev = local64_xchg(&event->hw.prev_count, now);
9271 local64_add(now - prev, &event->count);
9274 static void cpu_clock_event_start(struct perf_event *event, int flags)
9276 local64_set(&event->hw.prev_count, local_clock());
9277 perf_swevent_start_hrtimer(event);
9280 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9282 perf_swevent_cancel_hrtimer(event);
9283 cpu_clock_event_update(event);
9286 static int cpu_clock_event_add(struct perf_event *event, int flags)
9288 if (flags & PERF_EF_START)
9289 cpu_clock_event_start(event, flags);
9290 perf_event_update_userpage(event);
9295 static void cpu_clock_event_del(struct perf_event *event, int flags)
9297 cpu_clock_event_stop(event, flags);
9300 static void cpu_clock_event_read(struct perf_event *event)
9302 cpu_clock_event_update(event);
9305 static int cpu_clock_event_init(struct perf_event *event)
9307 if (event->attr.type != PERF_TYPE_SOFTWARE)
9310 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9314 * no branch sampling for software events
9316 if (has_branch_stack(event))
9319 perf_swevent_init_hrtimer(event);
9324 static struct pmu perf_cpu_clock = {
9325 .task_ctx_nr = perf_sw_context,
9327 .capabilities = PERF_PMU_CAP_NO_NMI,
9329 .event_init = cpu_clock_event_init,
9330 .add = cpu_clock_event_add,
9331 .del = cpu_clock_event_del,
9332 .start = cpu_clock_event_start,
9333 .stop = cpu_clock_event_stop,
9334 .read = cpu_clock_event_read,
9338 * Software event: task time clock
9341 static void task_clock_event_update(struct perf_event *event, u64 now)
9346 prev = local64_xchg(&event->hw.prev_count, now);
9348 local64_add(delta, &event->count);
9351 static void task_clock_event_start(struct perf_event *event, int flags)
9353 local64_set(&event->hw.prev_count, event->ctx->time);
9354 perf_swevent_start_hrtimer(event);
9357 static void task_clock_event_stop(struct perf_event *event, int flags)
9359 perf_swevent_cancel_hrtimer(event);
9360 task_clock_event_update(event, event->ctx->time);
9363 static int task_clock_event_add(struct perf_event *event, int flags)
9365 if (flags & PERF_EF_START)
9366 task_clock_event_start(event, flags);
9367 perf_event_update_userpage(event);
9372 static void task_clock_event_del(struct perf_event *event, int flags)
9374 task_clock_event_stop(event, PERF_EF_UPDATE);
9377 static void task_clock_event_read(struct perf_event *event)
9379 u64 now = perf_clock();
9380 u64 delta = now - event->ctx->timestamp;
9381 u64 time = event->ctx->time + delta;
9383 task_clock_event_update(event, time);
9386 static int task_clock_event_init(struct perf_event *event)
9388 if (event->attr.type != PERF_TYPE_SOFTWARE)
9391 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9395 * no branch sampling for software events
9397 if (has_branch_stack(event))
9400 perf_swevent_init_hrtimer(event);
9405 static struct pmu perf_task_clock = {
9406 .task_ctx_nr = perf_sw_context,
9408 .capabilities = PERF_PMU_CAP_NO_NMI,
9410 .event_init = task_clock_event_init,
9411 .add = task_clock_event_add,
9412 .del = task_clock_event_del,
9413 .start = task_clock_event_start,
9414 .stop = task_clock_event_stop,
9415 .read = task_clock_event_read,
9418 static void perf_pmu_nop_void(struct pmu *pmu)
9422 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9426 static int perf_pmu_nop_int(struct pmu *pmu)
9431 static int perf_event_nop_int(struct perf_event *event, u64 value)
9436 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9438 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9440 __this_cpu_write(nop_txn_flags, flags);
9442 if (flags & ~PERF_PMU_TXN_ADD)
9445 perf_pmu_disable(pmu);
9448 static int perf_pmu_commit_txn(struct pmu *pmu)
9450 unsigned int flags = __this_cpu_read(nop_txn_flags);
9452 __this_cpu_write(nop_txn_flags, 0);
9454 if (flags & ~PERF_PMU_TXN_ADD)
9457 perf_pmu_enable(pmu);
9461 static void perf_pmu_cancel_txn(struct pmu *pmu)
9463 unsigned int flags = __this_cpu_read(nop_txn_flags);
9465 __this_cpu_write(nop_txn_flags, 0);
9467 if (flags & ~PERF_PMU_TXN_ADD)
9470 perf_pmu_enable(pmu);
9473 static int perf_event_idx_default(struct perf_event *event)
9479 * Ensures all contexts with the same task_ctx_nr have the same
9480 * pmu_cpu_context too.
9482 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9489 list_for_each_entry(pmu, &pmus, entry) {
9490 if (pmu->task_ctx_nr == ctxn)
9491 return pmu->pmu_cpu_context;
9497 static void free_pmu_context(struct pmu *pmu)
9500 * Static contexts such as perf_sw_context have a global lifetime
9501 * and may be shared between different PMUs. Avoid freeing them
9502 * when a single PMU is going away.
9504 if (pmu->task_ctx_nr > perf_invalid_context)
9507 free_percpu(pmu->pmu_cpu_context);
9511 * Let userspace know that this PMU supports address range filtering:
9513 static ssize_t nr_addr_filters_show(struct device *dev,
9514 struct device_attribute *attr,
9517 struct pmu *pmu = dev_get_drvdata(dev);
9519 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9521 DEVICE_ATTR_RO(nr_addr_filters);
9523 static struct idr pmu_idr;
9526 type_show(struct device *dev, struct device_attribute *attr, char *page)
9528 struct pmu *pmu = dev_get_drvdata(dev);
9530 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9532 static DEVICE_ATTR_RO(type);
9535 perf_event_mux_interval_ms_show(struct device *dev,
9536 struct device_attribute *attr,
9539 struct pmu *pmu = dev_get_drvdata(dev);
9541 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9544 static DEFINE_MUTEX(mux_interval_mutex);
9547 perf_event_mux_interval_ms_store(struct device *dev,
9548 struct device_attribute *attr,
9549 const char *buf, size_t count)
9551 struct pmu *pmu = dev_get_drvdata(dev);
9552 int timer, cpu, ret;
9554 ret = kstrtoint(buf, 0, &timer);
9561 /* same value, noting to do */
9562 if (timer == pmu->hrtimer_interval_ms)
9565 mutex_lock(&mux_interval_mutex);
9566 pmu->hrtimer_interval_ms = timer;
9568 /* update all cpuctx for this PMU */
9570 for_each_online_cpu(cpu) {
9571 struct perf_cpu_context *cpuctx;
9572 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9573 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9575 cpu_function_call(cpu,
9576 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9579 mutex_unlock(&mux_interval_mutex);
9583 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9585 static struct attribute *pmu_dev_attrs[] = {
9586 &dev_attr_type.attr,
9587 &dev_attr_perf_event_mux_interval_ms.attr,
9590 ATTRIBUTE_GROUPS(pmu_dev);
9592 static int pmu_bus_running;
9593 static struct bus_type pmu_bus = {
9594 .name = "event_source",
9595 .dev_groups = pmu_dev_groups,
9598 static void pmu_dev_release(struct device *dev)
9603 static int pmu_dev_alloc(struct pmu *pmu)
9607 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9611 pmu->dev->groups = pmu->attr_groups;
9612 device_initialize(pmu->dev);
9613 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9617 dev_set_drvdata(pmu->dev, pmu);
9618 pmu->dev->bus = &pmu_bus;
9619 pmu->dev->release = pmu_dev_release;
9620 ret = device_add(pmu->dev);
9624 /* For PMUs with address filters, throw in an extra attribute: */
9625 if (pmu->nr_addr_filters)
9626 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9635 device_del(pmu->dev);
9638 put_device(pmu->dev);
9642 static struct lock_class_key cpuctx_mutex;
9643 static struct lock_class_key cpuctx_lock;
9645 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9649 mutex_lock(&pmus_lock);
9651 pmu->pmu_disable_count = alloc_percpu(int);
9652 if (!pmu->pmu_disable_count)
9661 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9669 if (pmu_bus_running) {
9670 ret = pmu_dev_alloc(pmu);
9676 if (pmu->task_ctx_nr == perf_hw_context) {
9677 static int hw_context_taken = 0;
9680 * Other than systems with heterogeneous CPUs, it never makes
9681 * sense for two PMUs to share perf_hw_context. PMUs which are
9682 * uncore must use perf_invalid_context.
9684 if (WARN_ON_ONCE(hw_context_taken &&
9685 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9686 pmu->task_ctx_nr = perf_invalid_context;
9688 hw_context_taken = 1;
9691 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9692 if (pmu->pmu_cpu_context)
9693 goto got_cpu_context;
9696 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9697 if (!pmu->pmu_cpu_context)
9700 for_each_possible_cpu(cpu) {
9701 struct perf_cpu_context *cpuctx;
9703 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9704 __perf_event_init_context(&cpuctx->ctx);
9705 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9706 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9707 cpuctx->ctx.pmu = pmu;
9708 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9710 __perf_mux_hrtimer_init(cpuctx, cpu);
9714 if (!pmu->start_txn) {
9715 if (pmu->pmu_enable) {
9717 * If we have pmu_enable/pmu_disable calls, install
9718 * transaction stubs that use that to try and batch
9719 * hardware accesses.
9721 pmu->start_txn = perf_pmu_start_txn;
9722 pmu->commit_txn = perf_pmu_commit_txn;
9723 pmu->cancel_txn = perf_pmu_cancel_txn;
9725 pmu->start_txn = perf_pmu_nop_txn;
9726 pmu->commit_txn = perf_pmu_nop_int;
9727 pmu->cancel_txn = perf_pmu_nop_void;
9731 if (!pmu->pmu_enable) {
9732 pmu->pmu_enable = perf_pmu_nop_void;
9733 pmu->pmu_disable = perf_pmu_nop_void;
9736 if (!pmu->check_period)
9737 pmu->check_period = perf_event_nop_int;
9739 if (!pmu->event_idx)
9740 pmu->event_idx = perf_event_idx_default;
9742 list_add_rcu(&pmu->entry, &pmus);
9743 atomic_set(&pmu->exclusive_cnt, 0);
9746 mutex_unlock(&pmus_lock);
9751 device_del(pmu->dev);
9752 put_device(pmu->dev);
9755 if (pmu->type >= PERF_TYPE_MAX)
9756 idr_remove(&pmu_idr, pmu->type);
9759 free_percpu(pmu->pmu_disable_count);
9762 EXPORT_SYMBOL_GPL(perf_pmu_register);
9764 void perf_pmu_unregister(struct pmu *pmu)
9766 mutex_lock(&pmus_lock);
9767 list_del_rcu(&pmu->entry);
9770 * We dereference the pmu list under both SRCU and regular RCU, so
9771 * synchronize against both of those.
9773 synchronize_srcu(&pmus_srcu);
9776 free_percpu(pmu->pmu_disable_count);
9777 if (pmu->type >= PERF_TYPE_MAX)
9778 idr_remove(&pmu_idr, pmu->type);
9779 if (pmu_bus_running) {
9780 if (pmu->nr_addr_filters)
9781 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9782 device_del(pmu->dev);
9783 put_device(pmu->dev);
9785 free_pmu_context(pmu);
9786 mutex_unlock(&pmus_lock);
9788 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9790 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9792 struct perf_event_context *ctx = NULL;
9795 if (!try_module_get(pmu->module))
9799 * A number of pmu->event_init() methods iterate the sibling_list to,
9800 * for example, validate if the group fits on the PMU. Therefore,
9801 * if this is a sibling event, acquire the ctx->mutex to protect
9804 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9806 * This ctx->mutex can nest when we're called through
9807 * inheritance. See the perf_event_ctx_lock_nested() comment.
9809 ctx = perf_event_ctx_lock_nested(event->group_leader,
9810 SINGLE_DEPTH_NESTING);
9815 ret = pmu->event_init(event);
9818 perf_event_ctx_unlock(event->group_leader, ctx);
9821 module_put(pmu->module);
9826 static struct pmu *perf_init_event(struct perf_event *event)
9832 idx = srcu_read_lock(&pmus_srcu);
9834 /* Try parent's PMU first: */
9835 if (event->parent && event->parent->pmu) {
9836 pmu = event->parent->pmu;
9837 ret = perf_try_init_event(pmu, event);
9843 pmu = idr_find(&pmu_idr, event->attr.type);
9846 ret = perf_try_init_event(pmu, event);
9852 list_for_each_entry_rcu(pmu, &pmus, entry) {
9853 ret = perf_try_init_event(pmu, event);
9857 if (ret != -ENOENT) {
9862 pmu = ERR_PTR(-ENOENT);
9864 srcu_read_unlock(&pmus_srcu, idx);
9869 static void attach_sb_event(struct perf_event *event)
9871 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9873 raw_spin_lock(&pel->lock);
9874 list_add_rcu(&event->sb_list, &pel->list);
9875 raw_spin_unlock(&pel->lock);
9879 * We keep a list of all !task (and therefore per-cpu) events
9880 * that need to receive side-band records.
9882 * This avoids having to scan all the various PMU per-cpu contexts
9885 static void account_pmu_sb_event(struct perf_event *event)
9887 if (is_sb_event(event))
9888 attach_sb_event(event);
9891 static void account_event_cpu(struct perf_event *event, int cpu)
9896 if (is_cgroup_event(event))
9897 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9900 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9901 static void account_freq_event_nohz(void)
9903 #ifdef CONFIG_NO_HZ_FULL
9904 /* Lock so we don't race with concurrent unaccount */
9905 spin_lock(&nr_freq_lock);
9906 if (atomic_inc_return(&nr_freq_events) == 1)
9907 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9908 spin_unlock(&nr_freq_lock);
9912 static void account_freq_event(void)
9914 if (tick_nohz_full_enabled())
9915 account_freq_event_nohz();
9917 atomic_inc(&nr_freq_events);
9921 static void account_event(struct perf_event *event)
9928 if (event->attach_state & PERF_ATTACH_TASK)
9930 if (event->attr.mmap || event->attr.mmap_data)
9931 atomic_inc(&nr_mmap_events);
9932 if (event->attr.comm)
9933 atomic_inc(&nr_comm_events);
9934 if (event->attr.namespaces)
9935 atomic_inc(&nr_namespaces_events);
9936 if (event->attr.task)
9937 atomic_inc(&nr_task_events);
9938 if (event->attr.freq)
9939 account_freq_event();
9940 if (event->attr.context_switch) {
9941 atomic_inc(&nr_switch_events);
9944 if (has_branch_stack(event))
9946 if (is_cgroup_event(event))
9951 * We need the mutex here because static_branch_enable()
9952 * must complete *before* the perf_sched_count increment
9955 if (atomic_inc_not_zero(&perf_sched_count))
9958 mutex_lock(&perf_sched_mutex);
9959 if (!atomic_read(&perf_sched_count)) {
9960 static_branch_enable(&perf_sched_events);
9962 * Guarantee that all CPUs observe they key change and
9963 * call the perf scheduling hooks before proceeding to
9964 * install events that need them.
9966 synchronize_sched();
9969 * Now that we have waited for the sync_sched(), allow further
9970 * increments to by-pass the mutex.
9972 atomic_inc(&perf_sched_count);
9973 mutex_unlock(&perf_sched_mutex);
9977 account_event_cpu(event, event->cpu);
9979 account_pmu_sb_event(event);
9983 * Allocate and initialize an event structure
9985 static struct perf_event *
9986 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9987 struct task_struct *task,
9988 struct perf_event *group_leader,
9989 struct perf_event *parent_event,
9990 perf_overflow_handler_t overflow_handler,
9991 void *context, int cgroup_fd)
9994 struct perf_event *event;
9995 struct hw_perf_event *hwc;
9998 if ((unsigned)cpu >= nr_cpu_ids) {
9999 if (!task || cpu != -1)
10000 return ERR_PTR(-EINVAL);
10003 event = kzalloc(sizeof(*event), GFP_KERNEL);
10005 return ERR_PTR(-ENOMEM);
10008 * Single events are their own group leaders, with an
10009 * empty sibling list:
10012 group_leader = event;
10014 mutex_init(&event->child_mutex);
10015 INIT_LIST_HEAD(&event->child_list);
10017 INIT_LIST_HEAD(&event->event_entry);
10018 INIT_LIST_HEAD(&event->sibling_list);
10019 INIT_LIST_HEAD(&event->active_list);
10020 init_event_group(event);
10021 INIT_LIST_HEAD(&event->rb_entry);
10022 INIT_LIST_HEAD(&event->active_entry);
10023 INIT_LIST_HEAD(&event->addr_filters.list);
10024 INIT_HLIST_NODE(&event->hlist_entry);
10027 init_waitqueue_head(&event->waitq);
10028 event->pending_disable = -1;
10029 init_irq_work(&event->pending, perf_pending_event);
10031 mutex_init(&event->mmap_mutex);
10032 raw_spin_lock_init(&event->addr_filters.lock);
10034 atomic_long_set(&event->refcount, 1);
10036 event->attr = *attr;
10037 event->group_leader = group_leader;
10041 event->parent = parent_event;
10043 event->ns = get_pid_ns(task_active_pid_ns(current));
10044 event->id = atomic64_inc_return(&perf_event_id);
10046 event->state = PERF_EVENT_STATE_INACTIVE;
10049 event->attach_state = PERF_ATTACH_TASK;
10051 * XXX pmu::event_init needs to know what task to account to
10052 * and we cannot use the ctx information because we need the
10053 * pmu before we get a ctx.
10055 get_task_struct(task);
10056 event->hw.target = task;
10059 event->clock = &local_clock;
10061 event->clock = parent_event->clock;
10063 if (!overflow_handler && parent_event) {
10064 overflow_handler = parent_event->overflow_handler;
10065 context = parent_event->overflow_handler_context;
10066 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10067 if (overflow_handler == bpf_overflow_handler) {
10068 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10070 if (IS_ERR(prog)) {
10071 err = PTR_ERR(prog);
10074 event->prog = prog;
10075 event->orig_overflow_handler =
10076 parent_event->orig_overflow_handler;
10081 if (overflow_handler) {
10082 event->overflow_handler = overflow_handler;
10083 event->overflow_handler_context = context;
10084 } else if (is_write_backward(event)){
10085 event->overflow_handler = perf_event_output_backward;
10086 event->overflow_handler_context = NULL;
10088 event->overflow_handler = perf_event_output_forward;
10089 event->overflow_handler_context = NULL;
10092 perf_event__state_init(event);
10097 hwc->sample_period = attr->sample_period;
10098 if (attr->freq && attr->sample_freq)
10099 hwc->sample_period = 1;
10100 hwc->last_period = hwc->sample_period;
10102 local64_set(&hwc->period_left, hwc->sample_period);
10105 * We currently do not support PERF_SAMPLE_READ on inherited events.
10106 * See perf_output_read().
10108 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10111 if (!has_branch_stack(event))
10112 event->attr.branch_sample_type = 0;
10114 if (cgroup_fd != -1) {
10115 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10120 pmu = perf_init_event(event);
10122 err = PTR_ERR(pmu);
10126 err = exclusive_event_init(event);
10130 if (has_addr_filter(event)) {
10131 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
10132 sizeof(unsigned long),
10134 if (!event->addr_filters_offs) {
10139 /* force hw sync on the address filters */
10140 event->addr_filters_gen = 1;
10143 if (!event->parent) {
10144 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10145 err = get_callchain_buffers(attr->sample_max_stack);
10147 goto err_addr_filters;
10151 /* symmetric to unaccount_event() in _free_event() */
10152 account_event(event);
10157 kfree(event->addr_filters_offs);
10160 exclusive_event_destroy(event);
10163 if (event->destroy)
10164 event->destroy(event);
10165 module_put(pmu->module);
10167 if (is_cgroup_event(event))
10168 perf_detach_cgroup(event);
10170 put_pid_ns(event->ns);
10171 if (event->hw.target)
10172 put_task_struct(event->hw.target);
10175 return ERR_PTR(err);
10178 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10179 struct perf_event_attr *attr)
10184 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10188 * zero the full structure, so that a short copy will be nice.
10190 memset(attr, 0, sizeof(*attr));
10192 ret = get_user(size, &uattr->size);
10196 if (size > PAGE_SIZE) /* silly large */
10199 if (!size) /* abi compat */
10200 size = PERF_ATTR_SIZE_VER0;
10202 if (size < PERF_ATTR_SIZE_VER0)
10206 * If we're handed a bigger struct than we know of,
10207 * ensure all the unknown bits are 0 - i.e. new
10208 * user-space does not rely on any kernel feature
10209 * extensions we dont know about yet.
10211 if (size > sizeof(*attr)) {
10212 unsigned char __user *addr;
10213 unsigned char __user *end;
10216 addr = (void __user *)uattr + sizeof(*attr);
10217 end = (void __user *)uattr + size;
10219 for (; addr < end; addr++) {
10220 ret = get_user(val, addr);
10226 size = sizeof(*attr);
10229 ret = copy_from_user(attr, uattr, size);
10235 if (attr->__reserved_1)
10238 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10241 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10244 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10245 u64 mask = attr->branch_sample_type;
10247 /* only using defined bits */
10248 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10251 /* at least one branch bit must be set */
10252 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10255 /* propagate priv level, when not set for branch */
10256 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10258 /* exclude_kernel checked on syscall entry */
10259 if (!attr->exclude_kernel)
10260 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10262 if (!attr->exclude_user)
10263 mask |= PERF_SAMPLE_BRANCH_USER;
10265 if (!attr->exclude_hv)
10266 mask |= PERF_SAMPLE_BRANCH_HV;
10268 * adjust user setting (for HW filter setup)
10270 attr->branch_sample_type = mask;
10272 /* privileged levels capture (kernel, hv): check permissions */
10273 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10274 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10278 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10279 ret = perf_reg_validate(attr->sample_regs_user);
10284 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10285 if (!arch_perf_have_user_stack_dump())
10289 * We have __u32 type for the size, but so far
10290 * we can only use __u16 as maximum due to the
10291 * __u16 sample size limit.
10293 if (attr->sample_stack_user >= USHRT_MAX)
10295 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10299 if (!attr->sample_max_stack)
10300 attr->sample_max_stack = sysctl_perf_event_max_stack;
10302 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10303 ret = perf_reg_validate(attr->sample_regs_intr);
10308 put_user(sizeof(*attr), &uattr->size);
10314 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10316 struct ring_buffer *rb = NULL;
10322 /* don't allow circular references */
10323 if (event == output_event)
10327 * Don't allow cross-cpu buffers
10329 if (output_event->cpu != event->cpu)
10333 * If its not a per-cpu rb, it must be the same task.
10335 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10339 * Mixing clocks in the same buffer is trouble you don't need.
10341 if (output_event->clock != event->clock)
10345 * Either writing ring buffer from beginning or from end.
10346 * Mixing is not allowed.
10348 if (is_write_backward(output_event) != is_write_backward(event))
10352 * If both events generate aux data, they must be on the same PMU
10354 if (has_aux(event) && has_aux(output_event) &&
10355 event->pmu != output_event->pmu)
10359 mutex_lock(&event->mmap_mutex);
10360 /* Can't redirect output if we've got an active mmap() */
10361 if (atomic_read(&event->mmap_count))
10364 if (output_event) {
10365 /* get the rb we want to redirect to */
10366 rb = ring_buffer_get(output_event);
10371 ring_buffer_attach(event, rb);
10375 mutex_unlock(&event->mmap_mutex);
10381 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10387 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10390 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10392 bool nmi_safe = false;
10395 case CLOCK_MONOTONIC:
10396 event->clock = &ktime_get_mono_fast_ns;
10400 case CLOCK_MONOTONIC_RAW:
10401 event->clock = &ktime_get_raw_fast_ns;
10405 case CLOCK_REALTIME:
10406 event->clock = &ktime_get_real_ns;
10409 case CLOCK_BOOTTIME:
10410 event->clock = &ktime_get_boot_ns;
10414 event->clock = &ktime_get_tai_ns;
10421 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10428 * Variation on perf_event_ctx_lock_nested(), except we take two context
10431 static struct perf_event_context *
10432 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10433 struct perf_event_context *ctx)
10435 struct perf_event_context *gctx;
10439 gctx = READ_ONCE(group_leader->ctx);
10440 if (!atomic_inc_not_zero(&gctx->refcount)) {
10446 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10448 if (group_leader->ctx != gctx) {
10449 mutex_unlock(&ctx->mutex);
10450 mutex_unlock(&gctx->mutex);
10459 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10461 * @attr_uptr: event_id type attributes for monitoring/sampling
10464 * @group_fd: group leader event fd
10466 SYSCALL_DEFINE5(perf_event_open,
10467 struct perf_event_attr __user *, attr_uptr,
10468 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10470 struct perf_event *group_leader = NULL, *output_event = NULL;
10471 struct perf_event *event, *sibling;
10472 struct perf_event_attr attr;
10473 struct perf_event_context *ctx, *uninitialized_var(gctx);
10474 struct file *event_file = NULL;
10475 struct fd group = {NULL, 0};
10476 struct task_struct *task = NULL;
10479 int move_group = 0;
10481 int f_flags = O_RDWR;
10482 int cgroup_fd = -1;
10484 /* for future expandability... */
10485 if (flags & ~PERF_FLAG_ALL)
10488 err = perf_copy_attr(attr_uptr, &attr);
10492 if (!attr.exclude_kernel) {
10493 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10497 if (attr.namespaces) {
10498 if (!capable(CAP_SYS_ADMIN))
10503 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10506 if (attr.sample_period & (1ULL << 63))
10510 /* Only privileged users can get physical addresses */
10511 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10512 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10516 * In cgroup mode, the pid argument is used to pass the fd
10517 * opened to the cgroup directory in cgroupfs. The cpu argument
10518 * designates the cpu on which to monitor threads from that
10521 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10524 if (flags & PERF_FLAG_FD_CLOEXEC)
10525 f_flags |= O_CLOEXEC;
10527 event_fd = get_unused_fd_flags(f_flags);
10531 if (group_fd != -1) {
10532 err = perf_fget_light(group_fd, &group);
10535 group_leader = group.file->private_data;
10536 if (flags & PERF_FLAG_FD_OUTPUT)
10537 output_event = group_leader;
10538 if (flags & PERF_FLAG_FD_NO_GROUP)
10539 group_leader = NULL;
10542 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10543 task = find_lively_task_by_vpid(pid);
10544 if (IS_ERR(task)) {
10545 err = PTR_ERR(task);
10550 if (task && group_leader &&
10551 group_leader->attr.inherit != attr.inherit) {
10557 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10562 * Reuse ptrace permission checks for now.
10564 * We must hold cred_guard_mutex across this and any potential
10565 * perf_install_in_context() call for this new event to
10566 * serialize against exec() altering our credentials (and the
10567 * perf_event_exit_task() that could imply).
10570 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10574 if (flags & PERF_FLAG_PID_CGROUP)
10577 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10578 NULL, NULL, cgroup_fd);
10579 if (IS_ERR(event)) {
10580 err = PTR_ERR(event);
10584 if (is_sampling_event(event)) {
10585 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10592 * Special case software events and allow them to be part of
10593 * any hardware group.
10597 if (attr.use_clockid) {
10598 err = perf_event_set_clock(event, attr.clockid);
10603 if (pmu->task_ctx_nr == perf_sw_context)
10604 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10606 if (group_leader) {
10607 if (is_software_event(event) &&
10608 !in_software_context(group_leader)) {
10610 * If the event is a sw event, but the group_leader
10611 * is on hw context.
10613 * Allow the addition of software events to hw
10614 * groups, this is safe because software events
10615 * never fail to schedule.
10617 pmu = group_leader->ctx->pmu;
10618 } else if (!is_software_event(event) &&
10619 is_software_event(group_leader) &&
10620 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10622 * In case the group is a pure software group, and we
10623 * try to add a hardware event, move the whole group to
10624 * the hardware context.
10631 * Get the target context (task or percpu):
10633 ctx = find_get_context(pmu, task, event);
10635 err = PTR_ERR(ctx);
10640 * Look up the group leader (we will attach this event to it):
10642 if (group_leader) {
10646 * Do not allow a recursive hierarchy (this new sibling
10647 * becoming part of another group-sibling):
10649 if (group_leader->group_leader != group_leader)
10652 /* All events in a group should have the same clock */
10653 if (group_leader->clock != event->clock)
10657 * Make sure we're both events for the same CPU;
10658 * grouping events for different CPUs is broken; since
10659 * you can never concurrently schedule them anyhow.
10661 if (group_leader->cpu != event->cpu)
10665 * Make sure we're both on the same task, or both
10668 if (group_leader->ctx->task != ctx->task)
10672 * Do not allow to attach to a group in a different task
10673 * or CPU context. If we're moving SW events, we'll fix
10674 * this up later, so allow that.
10676 if (!move_group && group_leader->ctx != ctx)
10680 * Only a group leader can be exclusive or pinned
10682 if (attr.exclusive || attr.pinned)
10686 if (output_event) {
10687 err = perf_event_set_output(event, output_event);
10692 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10694 if (IS_ERR(event_file)) {
10695 err = PTR_ERR(event_file);
10701 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10703 if (gctx->task == TASK_TOMBSTONE) {
10709 * Check if we raced against another sys_perf_event_open() call
10710 * moving the software group underneath us.
10712 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10714 * If someone moved the group out from under us, check
10715 * if this new event wound up on the same ctx, if so
10716 * its the regular !move_group case, otherwise fail.
10722 perf_event_ctx_unlock(group_leader, gctx);
10728 * Failure to create exclusive events returns -EBUSY.
10731 if (!exclusive_event_installable(group_leader, ctx))
10734 for_each_sibling_event(sibling, group_leader) {
10735 if (!exclusive_event_installable(sibling, ctx))
10739 mutex_lock(&ctx->mutex);
10742 if (ctx->task == TASK_TOMBSTONE) {
10747 if (!perf_event_validate_size(event)) {
10754 * Check if the @cpu we're creating an event for is online.
10756 * We use the perf_cpu_context::ctx::mutex to serialize against
10757 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10759 struct perf_cpu_context *cpuctx =
10760 container_of(ctx, struct perf_cpu_context, ctx);
10762 if (!cpuctx->online) {
10770 * Must be under the same ctx::mutex as perf_install_in_context(),
10771 * because we need to serialize with concurrent event creation.
10773 if (!exclusive_event_installable(event, ctx)) {
10778 WARN_ON_ONCE(ctx->parent_ctx);
10781 * This is the point on no return; we cannot fail hereafter. This is
10782 * where we start modifying current state.
10787 * See perf_event_ctx_lock() for comments on the details
10788 * of swizzling perf_event::ctx.
10790 perf_remove_from_context(group_leader, 0);
10793 for_each_sibling_event(sibling, group_leader) {
10794 perf_remove_from_context(sibling, 0);
10799 * Wait for everybody to stop referencing the events through
10800 * the old lists, before installing it on new lists.
10805 * Install the group siblings before the group leader.
10807 * Because a group leader will try and install the entire group
10808 * (through the sibling list, which is still in-tact), we can
10809 * end up with siblings installed in the wrong context.
10811 * By installing siblings first we NO-OP because they're not
10812 * reachable through the group lists.
10814 for_each_sibling_event(sibling, group_leader) {
10815 perf_event__state_init(sibling);
10816 perf_install_in_context(ctx, sibling, sibling->cpu);
10821 * Removing from the context ends up with disabled
10822 * event. What we want here is event in the initial
10823 * startup state, ready to be add into new context.
10825 perf_event__state_init(group_leader);
10826 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10831 * Precalculate sample_data sizes; do while holding ctx::mutex such
10832 * that we're serialized against further additions and before
10833 * perf_install_in_context() which is the point the event is active and
10834 * can use these values.
10836 perf_event__header_size(event);
10837 perf_event__id_header_size(event);
10839 event->owner = current;
10841 perf_install_in_context(ctx, event, event->cpu);
10842 perf_unpin_context(ctx);
10845 perf_event_ctx_unlock(group_leader, gctx);
10846 mutex_unlock(&ctx->mutex);
10849 mutex_unlock(&task->signal->cred_guard_mutex);
10850 put_task_struct(task);
10853 mutex_lock(¤t->perf_event_mutex);
10854 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10855 mutex_unlock(¤t->perf_event_mutex);
10858 * Drop the reference on the group_event after placing the
10859 * new event on the sibling_list. This ensures destruction
10860 * of the group leader will find the pointer to itself in
10861 * perf_group_detach().
10864 fd_install(event_fd, event_file);
10869 perf_event_ctx_unlock(group_leader, gctx);
10870 mutex_unlock(&ctx->mutex);
10874 perf_unpin_context(ctx);
10878 * If event_file is set, the fput() above will have called ->release()
10879 * and that will take care of freeing the event.
10885 mutex_unlock(&task->signal->cred_guard_mutex);
10888 put_task_struct(task);
10892 put_unused_fd(event_fd);
10897 * perf_event_create_kernel_counter
10899 * @attr: attributes of the counter to create
10900 * @cpu: cpu in which the counter is bound
10901 * @task: task to profile (NULL for percpu)
10903 struct perf_event *
10904 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10905 struct task_struct *task,
10906 perf_overflow_handler_t overflow_handler,
10909 struct perf_event_context *ctx;
10910 struct perf_event *event;
10914 * Get the target context (task or percpu):
10917 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10918 overflow_handler, context, -1);
10919 if (IS_ERR(event)) {
10920 err = PTR_ERR(event);
10924 /* Mark owner so we could distinguish it from user events. */
10925 event->owner = TASK_TOMBSTONE;
10927 ctx = find_get_context(event->pmu, task, event);
10929 err = PTR_ERR(ctx);
10933 WARN_ON_ONCE(ctx->parent_ctx);
10934 mutex_lock(&ctx->mutex);
10935 if (ctx->task == TASK_TOMBSTONE) {
10942 * Check if the @cpu we're creating an event for is online.
10944 * We use the perf_cpu_context::ctx::mutex to serialize against
10945 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10947 struct perf_cpu_context *cpuctx =
10948 container_of(ctx, struct perf_cpu_context, ctx);
10949 if (!cpuctx->online) {
10955 if (!exclusive_event_installable(event, ctx)) {
10960 perf_install_in_context(ctx, event, cpu);
10961 perf_unpin_context(ctx);
10962 mutex_unlock(&ctx->mutex);
10967 mutex_unlock(&ctx->mutex);
10968 perf_unpin_context(ctx);
10973 return ERR_PTR(err);
10975 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10977 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10979 struct perf_event_context *src_ctx;
10980 struct perf_event_context *dst_ctx;
10981 struct perf_event *event, *tmp;
10984 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10985 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10988 * See perf_event_ctx_lock() for comments on the details
10989 * of swizzling perf_event::ctx.
10991 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10992 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10994 perf_remove_from_context(event, 0);
10995 unaccount_event_cpu(event, src_cpu);
10997 list_add(&event->migrate_entry, &events);
11001 * Wait for the events to quiesce before re-instating them.
11006 * Re-instate events in 2 passes.
11008 * Skip over group leaders and only install siblings on this first
11009 * pass, siblings will not get enabled without a leader, however a
11010 * leader will enable its siblings, even if those are still on the old
11013 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11014 if (event->group_leader == event)
11017 list_del(&event->migrate_entry);
11018 if (event->state >= PERF_EVENT_STATE_OFF)
11019 event->state = PERF_EVENT_STATE_INACTIVE;
11020 account_event_cpu(event, dst_cpu);
11021 perf_install_in_context(dst_ctx, event, dst_cpu);
11026 * Once all the siblings are setup properly, install the group leaders
11029 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11030 list_del(&event->migrate_entry);
11031 if (event->state >= PERF_EVENT_STATE_OFF)
11032 event->state = PERF_EVENT_STATE_INACTIVE;
11033 account_event_cpu(event, dst_cpu);
11034 perf_install_in_context(dst_ctx, event, dst_cpu);
11037 mutex_unlock(&dst_ctx->mutex);
11038 mutex_unlock(&src_ctx->mutex);
11040 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11042 static void sync_child_event(struct perf_event *child_event,
11043 struct task_struct *child)
11045 struct perf_event *parent_event = child_event->parent;
11048 if (child_event->attr.inherit_stat)
11049 perf_event_read_event(child_event, child);
11051 child_val = perf_event_count(child_event);
11054 * Add back the child's count to the parent's count:
11056 atomic64_add(child_val, &parent_event->child_count);
11057 atomic64_add(child_event->total_time_enabled,
11058 &parent_event->child_total_time_enabled);
11059 atomic64_add(child_event->total_time_running,
11060 &parent_event->child_total_time_running);
11064 perf_event_exit_event(struct perf_event *child_event,
11065 struct perf_event_context *child_ctx,
11066 struct task_struct *child)
11068 struct perf_event *parent_event = child_event->parent;
11071 * Do not destroy the 'original' grouping; because of the context
11072 * switch optimization the original events could've ended up in a
11073 * random child task.
11075 * If we were to destroy the original group, all group related
11076 * operations would cease to function properly after this random
11079 * Do destroy all inherited groups, we don't care about those
11080 * and being thorough is better.
11082 raw_spin_lock_irq(&child_ctx->lock);
11083 WARN_ON_ONCE(child_ctx->is_active);
11086 perf_group_detach(child_event);
11087 list_del_event(child_event, child_ctx);
11088 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11089 raw_spin_unlock_irq(&child_ctx->lock);
11092 * Parent events are governed by their filedesc, retain them.
11094 if (!parent_event) {
11095 perf_event_wakeup(child_event);
11099 * Child events can be cleaned up.
11102 sync_child_event(child_event, child);
11105 * Remove this event from the parent's list
11107 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11108 mutex_lock(&parent_event->child_mutex);
11109 list_del_init(&child_event->child_list);
11110 mutex_unlock(&parent_event->child_mutex);
11113 * Kick perf_poll() for is_event_hup().
11115 perf_event_wakeup(parent_event);
11116 free_event(child_event);
11117 put_event(parent_event);
11120 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11122 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11123 struct perf_event *child_event, *next;
11125 WARN_ON_ONCE(child != current);
11127 child_ctx = perf_pin_task_context(child, ctxn);
11132 * In order to reduce the amount of tricky in ctx tear-down, we hold
11133 * ctx::mutex over the entire thing. This serializes against almost
11134 * everything that wants to access the ctx.
11136 * The exception is sys_perf_event_open() /
11137 * perf_event_create_kernel_count() which does find_get_context()
11138 * without ctx::mutex (it cannot because of the move_group double mutex
11139 * lock thing). See the comments in perf_install_in_context().
11141 mutex_lock(&child_ctx->mutex);
11144 * In a single ctx::lock section, de-schedule the events and detach the
11145 * context from the task such that we cannot ever get it scheduled back
11148 raw_spin_lock_irq(&child_ctx->lock);
11149 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11152 * Now that the context is inactive, destroy the task <-> ctx relation
11153 * and mark the context dead.
11155 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11156 put_ctx(child_ctx); /* cannot be last */
11157 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11158 put_task_struct(current); /* cannot be last */
11160 clone_ctx = unclone_ctx(child_ctx);
11161 raw_spin_unlock_irq(&child_ctx->lock);
11164 put_ctx(clone_ctx);
11167 * Report the task dead after unscheduling the events so that we
11168 * won't get any samples after PERF_RECORD_EXIT. We can however still
11169 * get a few PERF_RECORD_READ events.
11171 perf_event_task(child, child_ctx, 0);
11173 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11174 perf_event_exit_event(child_event, child_ctx, child);
11176 mutex_unlock(&child_ctx->mutex);
11178 put_ctx(child_ctx);
11182 * When a child task exits, feed back event values to parent events.
11184 * Can be called with cred_guard_mutex held when called from
11185 * install_exec_creds().
11187 void perf_event_exit_task(struct task_struct *child)
11189 struct perf_event *event, *tmp;
11192 mutex_lock(&child->perf_event_mutex);
11193 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11195 list_del_init(&event->owner_entry);
11198 * Ensure the list deletion is visible before we clear
11199 * the owner, closes a race against perf_release() where
11200 * we need to serialize on the owner->perf_event_mutex.
11202 smp_store_release(&event->owner, NULL);
11204 mutex_unlock(&child->perf_event_mutex);
11206 for_each_task_context_nr(ctxn)
11207 perf_event_exit_task_context(child, ctxn);
11210 * The perf_event_exit_task_context calls perf_event_task
11211 * with child's task_ctx, which generates EXIT events for
11212 * child contexts and sets child->perf_event_ctxp[] to NULL.
11213 * At this point we need to send EXIT events to cpu contexts.
11215 perf_event_task(child, NULL, 0);
11218 static void perf_free_event(struct perf_event *event,
11219 struct perf_event_context *ctx)
11221 struct perf_event *parent = event->parent;
11223 if (WARN_ON_ONCE(!parent))
11226 mutex_lock(&parent->child_mutex);
11227 list_del_init(&event->child_list);
11228 mutex_unlock(&parent->child_mutex);
11232 raw_spin_lock_irq(&ctx->lock);
11233 perf_group_detach(event);
11234 list_del_event(event, ctx);
11235 raw_spin_unlock_irq(&ctx->lock);
11240 * Free a context as created by inheritance by perf_event_init_task() below,
11241 * used by fork() in case of fail.
11243 * Even though the task has never lived, the context and events have been
11244 * exposed through the child_list, so we must take care tearing it all down.
11246 void perf_event_free_task(struct task_struct *task)
11248 struct perf_event_context *ctx;
11249 struct perf_event *event, *tmp;
11252 for_each_task_context_nr(ctxn) {
11253 ctx = task->perf_event_ctxp[ctxn];
11257 mutex_lock(&ctx->mutex);
11258 raw_spin_lock_irq(&ctx->lock);
11260 * Destroy the task <-> ctx relation and mark the context dead.
11262 * This is important because even though the task hasn't been
11263 * exposed yet the context has been (through child_list).
11265 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11266 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11267 put_task_struct(task); /* cannot be last */
11268 raw_spin_unlock_irq(&ctx->lock);
11270 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11271 perf_free_event(event, ctx);
11273 mutex_unlock(&ctx->mutex);
11276 * perf_event_release_kernel() could've stolen some of our
11277 * child events and still have them on its free_list. In that
11278 * case we must wait for these events to have been freed (in
11279 * particular all their references to this task must've been
11282 * Without this copy_process() will unconditionally free this
11283 * task (irrespective of its reference count) and
11284 * _free_event()'s put_task_struct(event->hw.target) will be a
11287 * Wait for all events to drop their context reference.
11289 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11290 put_ctx(ctx); /* must be last */
11294 void perf_event_delayed_put(struct task_struct *task)
11298 for_each_task_context_nr(ctxn)
11299 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11302 struct file *perf_event_get(unsigned int fd)
11306 file = fget_raw(fd);
11308 return ERR_PTR(-EBADF);
11310 if (file->f_op != &perf_fops) {
11312 return ERR_PTR(-EBADF);
11318 const struct perf_event *perf_get_event(struct file *file)
11320 if (file->f_op != &perf_fops)
11321 return ERR_PTR(-EINVAL);
11323 return file->private_data;
11326 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11329 return ERR_PTR(-EINVAL);
11331 return &event->attr;
11335 * Inherit an event from parent task to child task.
11338 * - valid pointer on success
11339 * - NULL for orphaned events
11340 * - IS_ERR() on error
11342 static struct perf_event *
11343 inherit_event(struct perf_event *parent_event,
11344 struct task_struct *parent,
11345 struct perf_event_context *parent_ctx,
11346 struct task_struct *child,
11347 struct perf_event *group_leader,
11348 struct perf_event_context *child_ctx)
11350 enum perf_event_state parent_state = parent_event->state;
11351 struct perf_event *child_event;
11352 unsigned long flags;
11355 * Instead of creating recursive hierarchies of events,
11356 * we link inherited events back to the original parent,
11357 * which has a filp for sure, which we use as the reference
11360 if (parent_event->parent)
11361 parent_event = parent_event->parent;
11363 child_event = perf_event_alloc(&parent_event->attr,
11366 group_leader, parent_event,
11368 if (IS_ERR(child_event))
11369 return child_event;
11372 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11373 !child_ctx->task_ctx_data) {
11374 struct pmu *pmu = child_event->pmu;
11376 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11378 if (!child_ctx->task_ctx_data) {
11379 free_event(child_event);
11385 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11386 * must be under the same lock in order to serialize against
11387 * perf_event_release_kernel(), such that either we must observe
11388 * is_orphaned_event() or they will observe us on the child_list.
11390 mutex_lock(&parent_event->child_mutex);
11391 if (is_orphaned_event(parent_event) ||
11392 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11393 mutex_unlock(&parent_event->child_mutex);
11394 /* task_ctx_data is freed with child_ctx */
11395 free_event(child_event);
11399 get_ctx(child_ctx);
11402 * Make the child state follow the state of the parent event,
11403 * not its attr.disabled bit. We hold the parent's mutex,
11404 * so we won't race with perf_event_{en, dis}able_family.
11406 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11407 child_event->state = PERF_EVENT_STATE_INACTIVE;
11409 child_event->state = PERF_EVENT_STATE_OFF;
11411 if (parent_event->attr.freq) {
11412 u64 sample_period = parent_event->hw.sample_period;
11413 struct hw_perf_event *hwc = &child_event->hw;
11415 hwc->sample_period = sample_period;
11416 hwc->last_period = sample_period;
11418 local64_set(&hwc->period_left, sample_period);
11421 child_event->ctx = child_ctx;
11422 child_event->overflow_handler = parent_event->overflow_handler;
11423 child_event->overflow_handler_context
11424 = parent_event->overflow_handler_context;
11427 * Precalculate sample_data sizes
11429 perf_event__header_size(child_event);
11430 perf_event__id_header_size(child_event);
11433 * Link it up in the child's context:
11435 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11436 add_event_to_ctx(child_event, child_ctx);
11437 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11440 * Link this into the parent event's child list
11442 list_add_tail(&child_event->child_list, &parent_event->child_list);
11443 mutex_unlock(&parent_event->child_mutex);
11445 return child_event;
11449 * Inherits an event group.
11451 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11452 * This matches with perf_event_release_kernel() removing all child events.
11458 static int inherit_group(struct perf_event *parent_event,
11459 struct task_struct *parent,
11460 struct perf_event_context *parent_ctx,
11461 struct task_struct *child,
11462 struct perf_event_context *child_ctx)
11464 struct perf_event *leader;
11465 struct perf_event *sub;
11466 struct perf_event *child_ctr;
11468 leader = inherit_event(parent_event, parent, parent_ctx,
11469 child, NULL, child_ctx);
11470 if (IS_ERR(leader))
11471 return PTR_ERR(leader);
11473 * @leader can be NULL here because of is_orphaned_event(). In this
11474 * case inherit_event() will create individual events, similar to what
11475 * perf_group_detach() would do anyway.
11477 for_each_sibling_event(sub, parent_event) {
11478 child_ctr = inherit_event(sub, parent, parent_ctx,
11479 child, leader, child_ctx);
11480 if (IS_ERR(child_ctr))
11481 return PTR_ERR(child_ctr);
11487 * Creates the child task context and tries to inherit the event-group.
11489 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11490 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11491 * consistent with perf_event_release_kernel() removing all child events.
11498 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11499 struct perf_event_context *parent_ctx,
11500 struct task_struct *child, int ctxn,
11501 int *inherited_all)
11504 struct perf_event_context *child_ctx;
11506 if (!event->attr.inherit) {
11507 *inherited_all = 0;
11511 child_ctx = child->perf_event_ctxp[ctxn];
11514 * This is executed from the parent task context, so
11515 * inherit events that have been marked for cloning.
11516 * First allocate and initialize a context for the
11519 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11523 child->perf_event_ctxp[ctxn] = child_ctx;
11526 ret = inherit_group(event, parent, parent_ctx,
11530 *inherited_all = 0;
11536 * Initialize the perf_event context in task_struct
11538 static int perf_event_init_context(struct task_struct *child, int ctxn)
11540 struct perf_event_context *child_ctx, *parent_ctx;
11541 struct perf_event_context *cloned_ctx;
11542 struct perf_event *event;
11543 struct task_struct *parent = current;
11544 int inherited_all = 1;
11545 unsigned long flags;
11548 if (likely(!parent->perf_event_ctxp[ctxn]))
11552 * If the parent's context is a clone, pin it so it won't get
11553 * swapped under us.
11555 parent_ctx = perf_pin_task_context(parent, ctxn);
11560 * No need to check if parent_ctx != NULL here; since we saw
11561 * it non-NULL earlier, the only reason for it to become NULL
11562 * is if we exit, and since we're currently in the middle of
11563 * a fork we can't be exiting at the same time.
11567 * Lock the parent list. No need to lock the child - not PID
11568 * hashed yet and not running, so nobody can access it.
11570 mutex_lock(&parent_ctx->mutex);
11573 * We dont have to disable NMIs - we are only looking at
11574 * the list, not manipulating it:
11576 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11577 ret = inherit_task_group(event, parent, parent_ctx,
11578 child, ctxn, &inherited_all);
11584 * We can't hold ctx->lock when iterating the ->flexible_group list due
11585 * to allocations, but we need to prevent rotation because
11586 * rotate_ctx() will change the list from interrupt context.
11588 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11589 parent_ctx->rotate_disable = 1;
11590 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11592 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11593 ret = inherit_task_group(event, parent, parent_ctx,
11594 child, ctxn, &inherited_all);
11599 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11600 parent_ctx->rotate_disable = 0;
11602 child_ctx = child->perf_event_ctxp[ctxn];
11604 if (child_ctx && inherited_all) {
11606 * Mark the child context as a clone of the parent
11607 * context, or of whatever the parent is a clone of.
11609 * Note that if the parent is a clone, the holding of
11610 * parent_ctx->lock avoids it from being uncloned.
11612 cloned_ctx = parent_ctx->parent_ctx;
11614 child_ctx->parent_ctx = cloned_ctx;
11615 child_ctx->parent_gen = parent_ctx->parent_gen;
11617 child_ctx->parent_ctx = parent_ctx;
11618 child_ctx->parent_gen = parent_ctx->generation;
11620 get_ctx(child_ctx->parent_ctx);
11623 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11625 mutex_unlock(&parent_ctx->mutex);
11627 perf_unpin_context(parent_ctx);
11628 put_ctx(parent_ctx);
11634 * Initialize the perf_event context in task_struct
11636 int perf_event_init_task(struct task_struct *child)
11640 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11641 mutex_init(&child->perf_event_mutex);
11642 INIT_LIST_HEAD(&child->perf_event_list);
11644 for_each_task_context_nr(ctxn) {
11645 ret = perf_event_init_context(child, ctxn);
11647 perf_event_free_task(child);
11655 static void __init perf_event_init_all_cpus(void)
11657 struct swevent_htable *swhash;
11660 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11662 for_each_possible_cpu(cpu) {
11663 swhash = &per_cpu(swevent_htable, cpu);
11664 mutex_init(&swhash->hlist_mutex);
11665 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11667 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11668 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11670 #ifdef CONFIG_CGROUP_PERF
11671 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11673 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11677 void perf_swevent_init_cpu(unsigned int cpu)
11679 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11681 mutex_lock(&swhash->hlist_mutex);
11682 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11683 struct swevent_hlist *hlist;
11685 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11687 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11689 mutex_unlock(&swhash->hlist_mutex);
11692 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11693 static void __perf_event_exit_context(void *__info)
11695 struct perf_event_context *ctx = __info;
11696 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11697 struct perf_event *event;
11699 raw_spin_lock(&ctx->lock);
11700 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11701 list_for_each_entry(event, &ctx->event_list, event_entry)
11702 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11703 raw_spin_unlock(&ctx->lock);
11706 static void perf_event_exit_cpu_context(int cpu)
11708 struct perf_cpu_context *cpuctx;
11709 struct perf_event_context *ctx;
11712 mutex_lock(&pmus_lock);
11713 list_for_each_entry(pmu, &pmus, entry) {
11714 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11715 ctx = &cpuctx->ctx;
11717 mutex_lock(&ctx->mutex);
11718 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11719 cpuctx->online = 0;
11720 mutex_unlock(&ctx->mutex);
11722 cpumask_clear_cpu(cpu, perf_online_mask);
11723 mutex_unlock(&pmus_lock);
11727 static void perf_event_exit_cpu_context(int cpu) { }
11731 int perf_event_init_cpu(unsigned int cpu)
11733 struct perf_cpu_context *cpuctx;
11734 struct perf_event_context *ctx;
11737 perf_swevent_init_cpu(cpu);
11739 mutex_lock(&pmus_lock);
11740 cpumask_set_cpu(cpu, perf_online_mask);
11741 list_for_each_entry(pmu, &pmus, entry) {
11742 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11743 ctx = &cpuctx->ctx;
11745 mutex_lock(&ctx->mutex);
11746 cpuctx->online = 1;
11747 mutex_unlock(&ctx->mutex);
11749 mutex_unlock(&pmus_lock);
11754 int perf_event_exit_cpu(unsigned int cpu)
11756 perf_event_exit_cpu_context(cpu);
11761 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11765 for_each_online_cpu(cpu)
11766 perf_event_exit_cpu(cpu);
11772 * Run the perf reboot notifier at the very last possible moment so that
11773 * the generic watchdog code runs as long as possible.
11775 static struct notifier_block perf_reboot_notifier = {
11776 .notifier_call = perf_reboot,
11777 .priority = INT_MIN,
11780 void __init perf_event_init(void)
11784 idr_init(&pmu_idr);
11786 perf_event_init_all_cpus();
11787 init_srcu_struct(&pmus_srcu);
11788 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11789 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11790 perf_pmu_register(&perf_task_clock, NULL, -1);
11791 perf_tp_register();
11792 perf_event_init_cpu(smp_processor_id());
11793 register_reboot_notifier(&perf_reboot_notifier);
11795 ret = init_hw_breakpoint();
11796 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11799 * Build time assertion that we keep the data_head at the intended
11800 * location. IOW, validation we got the __reserved[] size right.
11802 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11806 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11809 struct perf_pmu_events_attr *pmu_attr =
11810 container_of(attr, struct perf_pmu_events_attr, attr);
11812 if (pmu_attr->event_str)
11813 return sprintf(page, "%s\n", pmu_attr->event_str);
11817 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11819 static int __init perf_event_sysfs_init(void)
11824 mutex_lock(&pmus_lock);
11826 ret = bus_register(&pmu_bus);
11830 list_for_each_entry(pmu, &pmus, entry) {
11831 if (!pmu->name || pmu->type < 0)
11834 ret = pmu_dev_alloc(pmu);
11835 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11837 pmu_bus_running = 1;
11841 mutex_unlock(&pmus_lock);
11845 device_initcall(perf_event_sysfs_init);
11847 #ifdef CONFIG_CGROUP_PERF
11848 static struct cgroup_subsys_state *
11849 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11851 struct perf_cgroup *jc;
11853 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11855 return ERR_PTR(-ENOMEM);
11857 jc->info = alloc_percpu(struct perf_cgroup_info);
11860 return ERR_PTR(-ENOMEM);
11866 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11868 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11870 free_percpu(jc->info);
11874 static int __perf_cgroup_move(void *info)
11876 struct task_struct *task = info;
11878 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11883 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11885 struct task_struct *task;
11886 struct cgroup_subsys_state *css;
11888 cgroup_taskset_for_each(task, css, tset)
11889 task_function_call(task, __perf_cgroup_move, task);
11892 struct cgroup_subsys perf_event_cgrp_subsys = {
11893 .css_alloc = perf_cgroup_css_alloc,
11894 .css_free = perf_cgroup_css_free,
11895 .attach = perf_cgroup_attach,
11897 * Implicitly enable on dfl hierarchy so that perf events can
11898 * always be filtered by cgroup2 path as long as perf_event
11899 * controller is not mounted on a legacy hierarchy.
11901 .implicit_on_dfl = true,
11904 #endif /* CONFIG_CGROUP_PERF */