2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
118 } while (ret == -EAGAIN);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu, remote_function_f func, void *info)
134 struct remote_function_call data = {
138 .ret = -ENXIO, /* No such CPU */
141 smp_call_function_single(cpu, remote_function, &data, 1);
146 static inline struct perf_cpu_context *
147 __get_cpu_context(struct perf_event_context *ctx)
149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
153 struct perf_event_context *ctx)
155 raw_spin_lock(&cpuctx->ctx.lock);
157 raw_spin_lock(&ctx->lock);
160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
161 struct perf_event_context *ctx)
164 raw_spin_unlock(&ctx->lock);
165 raw_spin_unlock(&cpuctx->ctx.lock);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event *event)
172 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
195 struct perf_event_context *, void *);
197 struct event_function_struct {
198 struct perf_event *event;
203 static int event_function(void *info)
205 struct event_function_struct *efs = info;
206 struct perf_event *event = efs->event;
207 struct perf_event_context *ctx = event->ctx;
208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
209 struct perf_event_context *task_ctx = cpuctx->task_ctx;
212 WARN_ON_ONCE(!irqs_disabled());
214 perf_ctx_lock(cpuctx, task_ctx);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx->task != current) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx->is_active);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx != ctx);
239 WARN_ON_ONCE(&cpuctx->ctx != ctx);
242 efs->func(event, cpuctx, ctx, efs->data);
244 perf_ctx_unlock(cpuctx, task_ctx);
249 static void event_function_call(struct perf_event *event, event_f func, void *data)
251 struct perf_event_context *ctx = event->ctx;
252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
253 struct event_function_struct efs = {
259 if (!event->parent) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx->mutex);
269 cpu_function_call(event->cpu, event_function, &efs);
273 if (task == TASK_TOMBSTONE)
277 if (!task_function_call(task, event_function, &efs))
280 raw_spin_lock_irq(&ctx->lock);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task == TASK_TOMBSTONE) {
287 raw_spin_unlock_irq(&ctx->lock);
290 if (ctx->is_active) {
291 raw_spin_unlock_irq(&ctx->lock);
294 func(event, NULL, ctx, data);
295 raw_spin_unlock_irq(&ctx->lock);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event *event, event_f func, void *data)
304 struct perf_event_context *ctx = event->ctx;
305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
306 struct task_struct *task = READ_ONCE(ctx->task);
307 struct perf_event_context *task_ctx = NULL;
309 WARN_ON_ONCE(!irqs_disabled());
312 if (task == TASK_TOMBSTONE)
318 perf_ctx_lock(cpuctx, task_ctx);
321 if (task == TASK_TOMBSTONE)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx->is_active) {
331 if (WARN_ON_ONCE(task != current))
334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
338 WARN_ON_ONCE(&cpuctx->ctx != ctx);
341 func(event, cpuctx, ctx, data);
343 perf_ctx_unlock(cpuctx, task_ctx);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE = 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct *work);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
375 static DEFINE_MUTEX(perf_sched_mutex);
376 static atomic_t perf_sched_count;
378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
382 static atomic_t nr_mmap_events __read_mostly;
383 static atomic_t nr_comm_events __read_mostly;
384 static atomic_t nr_namespaces_events __read_mostly;
385 static atomic_t nr_task_events __read_mostly;
386 static atomic_t nr_freq_events __read_mostly;
387 static atomic_t nr_switch_events __read_mostly;
389 static LIST_HEAD(pmus);
390 static DEFINE_MUTEX(pmus_lock);
391 static struct srcu_struct pmus_srcu;
392 static cpumask_var_t perf_online_mask;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly = 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
415 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
416 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
418 static int perf_sample_allowed_ns __read_mostly =
419 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp = perf_sample_period_ns;
425 tmp *= sysctl_perf_cpu_time_max_percent;
426 tmp = div_u64(tmp, 100);
430 WRITE_ONCE(perf_sample_allowed_ns, tmp);
433 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
435 int perf_proc_update_handler(struct ctl_table *table, int write,
436 void __user *buffer, size_t *lenp,
439 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
445 * If throttling is disabled don't allow the write:
447 if (sysctl_perf_cpu_time_max_percent == 100 ||
448 sysctl_perf_cpu_time_max_percent == 0)
451 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
452 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
461 void __user *buffer, size_t *lenp,
464 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
469 if (sysctl_perf_cpu_time_max_percent == 100 ||
470 sysctl_perf_cpu_time_max_percent == 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64, running_sample_length);
490 static u64 __report_avg;
491 static u64 __report_allowed;
493 static void perf_duration_warn(struct irq_work *w)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg, __report_allowed,
499 sysctl_perf_event_sample_rate);
502 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504 void perf_sample_event_took(u64 sample_len_ns)
506 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
514 /* Decay the counter by 1 average sample. */
515 running_len = __this_cpu_read(running_sample_length);
516 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
517 running_len += sample_len_ns;
518 __this_cpu_write(running_sample_length, running_len);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
526 if (avg_len <= max_len)
529 __report_avg = avg_len;
530 __report_allowed = max_len;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len += avg_len / 4;
536 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
542 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
543 WRITE_ONCE(max_samples_per_tick, max);
545 sysctl_perf_event_sample_rate = max * HZ;
546 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548 if (!irq_work_queue(&perf_duration_work)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg, __report_allowed,
552 sysctl_perf_event_sample_rate);
556 static atomic64_t perf_event_id;
558 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
559 enum event_type_t event_type);
561 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
562 enum event_type_t event_type,
563 struct task_struct *task);
565 static void update_context_time(struct perf_event_context *ctx);
566 static u64 perf_event_time(struct perf_event *event);
568 void __weak perf_event_print_debug(void) { }
570 extern __weak const char *perf_pmu_name(void)
575 static inline u64 perf_clock(void)
577 return local_clock();
580 static inline u64 perf_event_clock(struct perf_event *event)
582 return event->clock();
585 #ifdef CONFIG_CGROUP_PERF
588 perf_cgroup_match(struct perf_event *event)
590 struct perf_event_context *ctx = event->ctx;
591 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
593 /* @event doesn't care about cgroup */
597 /* wants specific cgroup scope but @cpuctx isn't associated with any */
602 * Cgroup scoping is recursive. An event enabled for a cgroup is
603 * also enabled for all its descendant cgroups. If @cpuctx's
604 * cgroup is a descendant of @event's (the test covers identity
605 * case), it's a match.
607 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
608 event->cgrp->css.cgroup);
611 static inline void perf_detach_cgroup(struct perf_event *event)
613 css_put(&event->cgrp->css);
617 static inline int is_cgroup_event(struct perf_event *event)
619 return event->cgrp != NULL;
622 static inline u64 perf_cgroup_event_time(struct perf_event *event)
624 struct perf_cgroup_info *t;
626 t = per_cpu_ptr(event->cgrp->info, event->cpu);
630 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
632 struct perf_cgroup_info *info;
637 info = this_cpu_ptr(cgrp->info);
639 info->time += now - info->timestamp;
640 info->timestamp = now;
643 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
645 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
647 __update_cgrp_time(cgrp_out);
650 static inline void update_cgrp_time_from_event(struct perf_event *event)
652 struct perf_cgroup *cgrp;
655 * ensure we access cgroup data only when needed and
656 * when we know the cgroup is pinned (css_get)
658 if (!is_cgroup_event(event))
661 cgrp = perf_cgroup_from_task(current, event->ctx);
663 * Do not update time when cgroup is not active
665 if (cgrp == event->cgrp)
666 __update_cgrp_time(event->cgrp);
670 perf_cgroup_set_timestamp(struct task_struct *task,
671 struct perf_event_context *ctx)
673 struct perf_cgroup *cgrp;
674 struct perf_cgroup_info *info;
677 * ctx->lock held by caller
678 * ensure we do not access cgroup data
679 * unless we have the cgroup pinned (css_get)
681 if (!task || !ctx->nr_cgroups)
684 cgrp = perf_cgroup_from_task(task, ctx);
685 info = this_cpu_ptr(cgrp->info);
686 info->timestamp = ctx->timestamp;
689 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
691 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
692 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
695 * reschedule events based on the cgroup constraint of task.
697 * mode SWOUT : schedule out everything
698 * mode SWIN : schedule in based on cgroup for next
700 static void perf_cgroup_switch(struct task_struct *task, int mode)
702 struct perf_cpu_context *cpuctx;
703 struct list_head *list;
707 * Disable interrupts and preemption to avoid this CPU's
708 * cgrp_cpuctx_entry to change under us.
710 local_irq_save(flags);
712 list = this_cpu_ptr(&cgrp_cpuctx_list);
713 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
714 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
716 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
717 perf_pmu_disable(cpuctx->ctx.pmu);
719 if (mode & PERF_CGROUP_SWOUT) {
720 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
722 * must not be done before ctxswout due
723 * to event_filter_match() in event_sched_out()
728 if (mode & PERF_CGROUP_SWIN) {
729 WARN_ON_ONCE(cpuctx->cgrp);
731 * set cgrp before ctxsw in to allow
732 * event_filter_match() to not have to pass
734 * we pass the cpuctx->ctx to perf_cgroup_from_task()
735 * because cgorup events are only per-cpu
737 cpuctx->cgrp = perf_cgroup_from_task(task,
739 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
741 perf_pmu_enable(cpuctx->ctx.pmu);
742 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
745 local_irq_restore(flags);
748 static inline void perf_cgroup_sched_out(struct task_struct *task,
749 struct task_struct *next)
751 struct perf_cgroup *cgrp1;
752 struct perf_cgroup *cgrp2 = NULL;
756 * we come here when we know perf_cgroup_events > 0
757 * we do not need to pass the ctx here because we know
758 * we are holding the rcu lock
760 cgrp1 = perf_cgroup_from_task(task, NULL);
761 cgrp2 = perf_cgroup_from_task(next, NULL);
764 * only schedule out current cgroup events if we know
765 * that we are switching to a different cgroup. Otherwise,
766 * do no touch the cgroup events.
769 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
774 static inline void perf_cgroup_sched_in(struct task_struct *prev,
775 struct task_struct *task)
777 struct perf_cgroup *cgrp1;
778 struct perf_cgroup *cgrp2 = NULL;
782 * we come here when we know perf_cgroup_events > 0
783 * we do not need to pass the ctx here because we know
784 * we are holding the rcu lock
786 cgrp1 = perf_cgroup_from_task(task, NULL);
787 cgrp2 = perf_cgroup_from_task(prev, NULL);
790 * only need to schedule in cgroup events if we are changing
791 * cgroup during ctxsw. Cgroup events were not scheduled
792 * out of ctxsw out if that was not the case.
795 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
800 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
801 struct perf_event_attr *attr,
802 struct perf_event *group_leader)
804 struct perf_cgroup *cgrp;
805 struct cgroup_subsys_state *css;
806 struct fd f = fdget(fd);
812 css = css_tryget_online_from_dir(f.file->f_path.dentry,
813 &perf_event_cgrp_subsys);
819 cgrp = container_of(css, struct perf_cgroup, css);
823 * all events in a group must monitor
824 * the same cgroup because a task belongs
825 * to only one perf cgroup at a time
827 if (group_leader && group_leader->cgrp != cgrp) {
828 perf_detach_cgroup(event);
837 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
839 struct perf_cgroup_info *t;
840 t = per_cpu_ptr(event->cgrp->info, event->cpu);
841 event->shadow_ctx_time = now - t->timestamp;
845 perf_cgroup_defer_enabled(struct perf_event *event)
848 * when the current task's perf cgroup does not match
849 * the event's, we need to remember to call the
850 * perf_mark_enable() function the first time a task with
851 * a matching perf cgroup is scheduled in.
853 if (is_cgroup_event(event) && !perf_cgroup_match(event))
854 event->cgrp_defer_enabled = 1;
858 perf_cgroup_mark_enabled(struct perf_event *event,
859 struct perf_event_context *ctx)
861 struct perf_event *sub;
862 u64 tstamp = perf_event_time(event);
864 if (!event->cgrp_defer_enabled)
867 event->cgrp_defer_enabled = 0;
869 event->tstamp_enabled = tstamp - event->total_time_enabled;
870 list_for_each_entry(sub, &event->sibling_list, group_entry) {
871 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
872 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
873 sub->cgrp_defer_enabled = 0;
879 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
880 * cleared when last cgroup event is removed.
883 list_update_cgroup_event(struct perf_event *event,
884 struct perf_event_context *ctx, bool add)
886 struct perf_cpu_context *cpuctx;
887 struct list_head *cpuctx_entry;
889 if (!is_cgroup_event(event))
892 if (add && ctx->nr_cgroups++)
894 else if (!add && --ctx->nr_cgroups)
897 * Because cgroup events are always per-cpu events,
898 * this will always be called from the right CPU.
900 cpuctx = __get_cpu_context(ctx);
901 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
902 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
904 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
905 if (perf_cgroup_from_task(current, ctx) == event->cgrp)
906 cpuctx->cgrp = event->cgrp;
908 list_del(cpuctx_entry);
913 #else /* !CONFIG_CGROUP_PERF */
916 perf_cgroup_match(struct perf_event *event)
921 static inline void perf_detach_cgroup(struct perf_event *event)
924 static inline int is_cgroup_event(struct perf_event *event)
929 static inline void update_cgrp_time_from_event(struct perf_event *event)
933 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
937 static inline void perf_cgroup_sched_out(struct task_struct *task,
938 struct task_struct *next)
942 static inline void perf_cgroup_sched_in(struct task_struct *prev,
943 struct task_struct *task)
947 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
948 struct perf_event_attr *attr,
949 struct perf_event *group_leader)
955 perf_cgroup_set_timestamp(struct task_struct *task,
956 struct perf_event_context *ctx)
961 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
966 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
970 static inline u64 perf_cgroup_event_time(struct perf_event *event)
976 perf_cgroup_defer_enabled(struct perf_event *event)
981 perf_cgroup_mark_enabled(struct perf_event *event,
982 struct perf_event_context *ctx)
987 list_update_cgroup_event(struct perf_event *event,
988 struct perf_event_context *ctx, bool add)
995 * set default to be dependent on timer tick just
998 #define PERF_CPU_HRTIMER (1000 / HZ)
1000 * function must be called with interrupts disabled
1002 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1004 struct perf_cpu_context *cpuctx;
1007 WARN_ON(!irqs_disabled());
1009 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1010 rotations = perf_rotate_context(cpuctx);
1012 raw_spin_lock(&cpuctx->hrtimer_lock);
1014 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1016 cpuctx->hrtimer_active = 0;
1017 raw_spin_unlock(&cpuctx->hrtimer_lock);
1019 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1022 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1024 struct hrtimer *timer = &cpuctx->hrtimer;
1025 struct pmu *pmu = cpuctx->ctx.pmu;
1028 /* no multiplexing needed for SW PMU */
1029 if (pmu->task_ctx_nr == perf_sw_context)
1033 * check default is sane, if not set then force to
1034 * default interval (1/tick)
1036 interval = pmu->hrtimer_interval_ms;
1038 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1040 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1042 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1043 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1044 timer->function = perf_mux_hrtimer_handler;
1047 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1049 struct hrtimer *timer = &cpuctx->hrtimer;
1050 struct pmu *pmu = cpuctx->ctx.pmu;
1051 unsigned long flags;
1053 /* not for SW PMU */
1054 if (pmu->task_ctx_nr == perf_sw_context)
1057 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1058 if (!cpuctx->hrtimer_active) {
1059 cpuctx->hrtimer_active = 1;
1060 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1061 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1063 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1068 void perf_pmu_disable(struct pmu *pmu)
1070 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1072 pmu->pmu_disable(pmu);
1075 void perf_pmu_enable(struct pmu *pmu)
1077 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1079 pmu->pmu_enable(pmu);
1082 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1085 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1086 * perf_event_task_tick() are fully serialized because they're strictly cpu
1087 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1088 * disabled, while perf_event_task_tick is called from IRQ context.
1090 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1092 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1094 WARN_ON(!irqs_disabled());
1096 WARN_ON(!list_empty(&ctx->active_ctx_list));
1098 list_add(&ctx->active_ctx_list, head);
1101 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1103 WARN_ON(!irqs_disabled());
1105 WARN_ON(list_empty(&ctx->active_ctx_list));
1107 list_del_init(&ctx->active_ctx_list);
1110 static void get_ctx(struct perf_event_context *ctx)
1112 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1115 static void free_ctx(struct rcu_head *head)
1117 struct perf_event_context *ctx;
1119 ctx = container_of(head, struct perf_event_context, rcu_head);
1120 kfree(ctx->task_ctx_data);
1124 static void put_ctx(struct perf_event_context *ctx)
1126 if (atomic_dec_and_test(&ctx->refcount)) {
1127 if (ctx->parent_ctx)
1128 put_ctx(ctx->parent_ctx);
1129 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1130 put_task_struct(ctx->task);
1131 call_rcu(&ctx->rcu_head, free_ctx);
1136 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1137 * perf_pmu_migrate_context() we need some magic.
1139 * Those places that change perf_event::ctx will hold both
1140 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1142 * Lock ordering is by mutex address. There are two other sites where
1143 * perf_event_context::mutex nests and those are:
1145 * - perf_event_exit_task_context() [ child , 0 ]
1146 * perf_event_exit_event()
1147 * put_event() [ parent, 1 ]
1149 * - perf_event_init_context() [ parent, 0 ]
1150 * inherit_task_group()
1153 * perf_event_alloc()
1155 * perf_try_init_event() [ child , 1 ]
1157 * While it appears there is an obvious deadlock here -- the parent and child
1158 * nesting levels are inverted between the two. This is in fact safe because
1159 * life-time rules separate them. That is an exiting task cannot fork, and a
1160 * spawning task cannot (yet) exit.
1162 * But remember that that these are parent<->child context relations, and
1163 * migration does not affect children, therefore these two orderings should not
1166 * The change in perf_event::ctx does not affect children (as claimed above)
1167 * because the sys_perf_event_open() case will install a new event and break
1168 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1169 * concerned with cpuctx and that doesn't have children.
1171 * The places that change perf_event::ctx will issue:
1173 * perf_remove_from_context();
1174 * synchronize_rcu();
1175 * perf_install_in_context();
1177 * to affect the change. The remove_from_context() + synchronize_rcu() should
1178 * quiesce the event, after which we can install it in the new location. This
1179 * means that only external vectors (perf_fops, prctl) can perturb the event
1180 * while in transit. Therefore all such accessors should also acquire
1181 * perf_event_context::mutex to serialize against this.
1183 * However; because event->ctx can change while we're waiting to acquire
1184 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1189 * task_struct::perf_event_mutex
1190 * perf_event_context::mutex
1191 * perf_event::child_mutex;
1192 * perf_event_context::lock
1193 * perf_event::mmap_mutex
1196 static struct perf_event_context *
1197 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1199 struct perf_event_context *ctx;
1203 ctx = ACCESS_ONCE(event->ctx);
1204 if (!atomic_inc_not_zero(&ctx->refcount)) {
1210 mutex_lock_nested(&ctx->mutex, nesting);
1211 if (event->ctx != ctx) {
1212 mutex_unlock(&ctx->mutex);
1220 static inline struct perf_event_context *
1221 perf_event_ctx_lock(struct perf_event *event)
1223 return perf_event_ctx_lock_nested(event, 0);
1226 static void perf_event_ctx_unlock(struct perf_event *event,
1227 struct perf_event_context *ctx)
1229 mutex_unlock(&ctx->mutex);
1234 * This must be done under the ctx->lock, such as to serialize against
1235 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1236 * calling scheduler related locks and ctx->lock nests inside those.
1238 static __must_check struct perf_event_context *
1239 unclone_ctx(struct perf_event_context *ctx)
1241 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1243 lockdep_assert_held(&ctx->lock);
1246 ctx->parent_ctx = NULL;
1252 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1255 * only top level events have the pid namespace they were created in
1258 event = event->parent;
1260 return task_tgid_nr_ns(p, event->ns);
1263 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1266 * only top level events have the pid namespace they were created in
1269 event = event->parent;
1271 return task_pid_nr_ns(p, event->ns);
1275 * If we inherit events we want to return the parent event id
1278 static u64 primary_event_id(struct perf_event *event)
1283 id = event->parent->id;
1289 * Get the perf_event_context for a task and lock it.
1291 * This has to cope with with the fact that until it is locked,
1292 * the context could get moved to another task.
1294 static struct perf_event_context *
1295 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1297 struct perf_event_context *ctx;
1301 * One of the few rules of preemptible RCU is that one cannot do
1302 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1303 * part of the read side critical section was irqs-enabled -- see
1304 * rcu_read_unlock_special().
1306 * Since ctx->lock nests under rq->lock we must ensure the entire read
1307 * side critical section has interrupts disabled.
1309 local_irq_save(*flags);
1311 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1314 * If this context is a clone of another, it might
1315 * get swapped for another underneath us by
1316 * perf_event_task_sched_out, though the
1317 * rcu_read_lock() protects us from any context
1318 * getting freed. Lock the context and check if it
1319 * got swapped before we could get the lock, and retry
1320 * if so. If we locked the right context, then it
1321 * can't get swapped on us any more.
1323 raw_spin_lock(&ctx->lock);
1324 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1325 raw_spin_unlock(&ctx->lock);
1327 local_irq_restore(*flags);
1331 if (ctx->task == TASK_TOMBSTONE ||
1332 !atomic_inc_not_zero(&ctx->refcount)) {
1333 raw_spin_unlock(&ctx->lock);
1336 WARN_ON_ONCE(ctx->task != task);
1341 local_irq_restore(*flags);
1346 * Get the context for a task and increment its pin_count so it
1347 * can't get swapped to another task. This also increments its
1348 * reference count so that the context can't get freed.
1350 static struct perf_event_context *
1351 perf_pin_task_context(struct task_struct *task, int ctxn)
1353 struct perf_event_context *ctx;
1354 unsigned long flags;
1356 ctx = perf_lock_task_context(task, ctxn, &flags);
1359 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1364 static void perf_unpin_context(struct perf_event_context *ctx)
1366 unsigned long flags;
1368 raw_spin_lock_irqsave(&ctx->lock, flags);
1370 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1374 * Update the record of the current time in a context.
1376 static void update_context_time(struct perf_event_context *ctx)
1378 u64 now = perf_clock();
1380 ctx->time += now - ctx->timestamp;
1381 ctx->timestamp = now;
1384 static u64 perf_event_time(struct perf_event *event)
1386 struct perf_event_context *ctx = event->ctx;
1388 if (is_cgroup_event(event))
1389 return perf_cgroup_event_time(event);
1391 return ctx ? ctx->time : 0;
1395 * Update the total_time_enabled and total_time_running fields for a event.
1397 static void update_event_times(struct perf_event *event)
1399 struct perf_event_context *ctx = event->ctx;
1402 lockdep_assert_held(&ctx->lock);
1404 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1405 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1409 * in cgroup mode, time_enabled represents
1410 * the time the event was enabled AND active
1411 * tasks were in the monitored cgroup. This is
1412 * independent of the activity of the context as
1413 * there may be a mix of cgroup and non-cgroup events.
1415 * That is why we treat cgroup events differently
1418 if (is_cgroup_event(event))
1419 run_end = perf_cgroup_event_time(event);
1420 else if (ctx->is_active)
1421 run_end = ctx->time;
1423 run_end = event->tstamp_stopped;
1425 event->total_time_enabled = run_end - event->tstamp_enabled;
1427 if (event->state == PERF_EVENT_STATE_INACTIVE)
1428 run_end = event->tstamp_stopped;
1430 run_end = perf_event_time(event);
1432 event->total_time_running = run_end - event->tstamp_running;
1437 * Update total_time_enabled and total_time_running for all events in a group.
1439 static void update_group_times(struct perf_event *leader)
1441 struct perf_event *event;
1443 update_event_times(leader);
1444 list_for_each_entry(event, &leader->sibling_list, group_entry)
1445 update_event_times(event);
1448 static enum event_type_t get_event_type(struct perf_event *event)
1450 struct perf_event_context *ctx = event->ctx;
1451 enum event_type_t event_type;
1453 lockdep_assert_held(&ctx->lock);
1456 * It's 'group type', really, because if our group leader is
1457 * pinned, so are we.
1459 if (event->group_leader != event)
1460 event = event->group_leader;
1462 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1464 event_type |= EVENT_CPU;
1469 static struct list_head *
1470 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1472 if (event->attr.pinned)
1473 return &ctx->pinned_groups;
1475 return &ctx->flexible_groups;
1479 * Add a event from the lists for its context.
1480 * Must be called with ctx->mutex and ctx->lock held.
1483 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1485 lockdep_assert_held(&ctx->lock);
1487 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1488 event->attach_state |= PERF_ATTACH_CONTEXT;
1491 * If we're a stand alone event or group leader, we go to the context
1492 * list, group events are kept attached to the group so that
1493 * perf_group_detach can, at all times, locate all siblings.
1495 if (event->group_leader == event) {
1496 struct list_head *list;
1498 event->group_caps = event->event_caps;
1500 list = ctx_group_list(event, ctx);
1501 list_add_tail(&event->group_entry, list);
1504 list_update_cgroup_event(event, ctx, true);
1506 list_add_rcu(&event->event_entry, &ctx->event_list);
1508 if (event->attr.inherit_stat)
1515 * Initialize event state based on the perf_event_attr::disabled.
1517 static inline void perf_event__state_init(struct perf_event *event)
1519 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1520 PERF_EVENT_STATE_INACTIVE;
1523 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1525 int entry = sizeof(u64); /* value */
1529 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1530 size += sizeof(u64);
1532 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1533 size += sizeof(u64);
1535 if (event->attr.read_format & PERF_FORMAT_ID)
1536 entry += sizeof(u64);
1538 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1540 size += sizeof(u64);
1544 event->read_size = size;
1547 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1549 struct perf_sample_data *data;
1552 if (sample_type & PERF_SAMPLE_IP)
1553 size += sizeof(data->ip);
1555 if (sample_type & PERF_SAMPLE_ADDR)
1556 size += sizeof(data->addr);
1558 if (sample_type & PERF_SAMPLE_PERIOD)
1559 size += sizeof(data->period);
1561 if (sample_type & PERF_SAMPLE_WEIGHT)
1562 size += sizeof(data->weight);
1564 if (sample_type & PERF_SAMPLE_READ)
1565 size += event->read_size;
1567 if (sample_type & PERF_SAMPLE_DATA_SRC)
1568 size += sizeof(data->data_src.val);
1570 if (sample_type & PERF_SAMPLE_TRANSACTION)
1571 size += sizeof(data->txn);
1573 event->header_size = size;
1577 * Called at perf_event creation and when events are attached/detached from a
1580 static void perf_event__header_size(struct perf_event *event)
1582 __perf_event_read_size(event,
1583 event->group_leader->nr_siblings);
1584 __perf_event_header_size(event, event->attr.sample_type);
1587 static void perf_event__id_header_size(struct perf_event *event)
1589 struct perf_sample_data *data;
1590 u64 sample_type = event->attr.sample_type;
1593 if (sample_type & PERF_SAMPLE_TID)
1594 size += sizeof(data->tid_entry);
1596 if (sample_type & PERF_SAMPLE_TIME)
1597 size += sizeof(data->time);
1599 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1600 size += sizeof(data->id);
1602 if (sample_type & PERF_SAMPLE_ID)
1603 size += sizeof(data->id);
1605 if (sample_type & PERF_SAMPLE_STREAM_ID)
1606 size += sizeof(data->stream_id);
1608 if (sample_type & PERF_SAMPLE_CPU)
1609 size += sizeof(data->cpu_entry);
1611 event->id_header_size = size;
1614 static bool perf_event_validate_size(struct perf_event *event)
1617 * The values computed here will be over-written when we actually
1620 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1621 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1622 perf_event__id_header_size(event);
1625 * Sum the lot; should not exceed the 64k limit we have on records.
1626 * Conservative limit to allow for callchains and other variable fields.
1628 if (event->read_size + event->header_size +
1629 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1635 static void perf_group_attach(struct perf_event *event)
1637 struct perf_event *group_leader = event->group_leader, *pos;
1639 lockdep_assert_held(&event->ctx->lock);
1642 * We can have double attach due to group movement in perf_event_open.
1644 if (event->attach_state & PERF_ATTACH_GROUP)
1647 event->attach_state |= PERF_ATTACH_GROUP;
1649 if (group_leader == event)
1652 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1654 group_leader->group_caps &= event->event_caps;
1656 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1657 group_leader->nr_siblings++;
1659 perf_event__header_size(group_leader);
1661 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1662 perf_event__header_size(pos);
1666 * Remove a event from the lists for its context.
1667 * Must be called with ctx->mutex and ctx->lock held.
1670 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1672 WARN_ON_ONCE(event->ctx != ctx);
1673 lockdep_assert_held(&ctx->lock);
1676 * We can have double detach due to exit/hot-unplug + close.
1678 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1681 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1683 list_update_cgroup_event(event, ctx, false);
1686 if (event->attr.inherit_stat)
1689 list_del_rcu(&event->event_entry);
1691 if (event->group_leader == event)
1692 list_del_init(&event->group_entry);
1694 update_group_times(event);
1697 * If event was in error state, then keep it
1698 * that way, otherwise bogus counts will be
1699 * returned on read(). The only way to get out
1700 * of error state is by explicit re-enabling
1703 if (event->state > PERF_EVENT_STATE_OFF)
1704 event->state = PERF_EVENT_STATE_OFF;
1709 static void perf_group_detach(struct perf_event *event)
1711 struct perf_event *sibling, *tmp;
1712 struct list_head *list = NULL;
1714 lockdep_assert_held(&event->ctx->lock);
1717 * We can have double detach due to exit/hot-unplug + close.
1719 if (!(event->attach_state & PERF_ATTACH_GROUP))
1722 event->attach_state &= ~PERF_ATTACH_GROUP;
1725 * If this is a sibling, remove it from its group.
1727 if (event->group_leader != event) {
1728 list_del_init(&event->group_entry);
1729 event->group_leader->nr_siblings--;
1733 if (!list_empty(&event->group_entry))
1734 list = &event->group_entry;
1737 * If this was a group event with sibling events then
1738 * upgrade the siblings to singleton events by adding them
1739 * to whatever list we are on.
1741 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1743 list_move_tail(&sibling->group_entry, list);
1744 sibling->group_leader = sibling;
1746 /* Inherit group flags from the previous leader */
1747 sibling->group_caps = event->group_caps;
1749 WARN_ON_ONCE(sibling->ctx != event->ctx);
1753 perf_event__header_size(event->group_leader);
1755 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1756 perf_event__header_size(tmp);
1759 static bool is_orphaned_event(struct perf_event *event)
1761 return event->state == PERF_EVENT_STATE_DEAD;
1764 static inline int __pmu_filter_match(struct perf_event *event)
1766 struct pmu *pmu = event->pmu;
1767 return pmu->filter_match ? pmu->filter_match(event) : 1;
1771 * Check whether we should attempt to schedule an event group based on
1772 * PMU-specific filtering. An event group can consist of HW and SW events,
1773 * potentially with a SW leader, so we must check all the filters, to
1774 * determine whether a group is schedulable:
1776 static inline int pmu_filter_match(struct perf_event *event)
1778 struct perf_event *child;
1780 if (!__pmu_filter_match(event))
1783 list_for_each_entry(child, &event->sibling_list, group_entry) {
1784 if (!__pmu_filter_match(child))
1792 event_filter_match(struct perf_event *event)
1794 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1795 perf_cgroup_match(event) && pmu_filter_match(event);
1799 event_sched_out(struct perf_event *event,
1800 struct perf_cpu_context *cpuctx,
1801 struct perf_event_context *ctx)
1803 u64 tstamp = perf_event_time(event);
1806 WARN_ON_ONCE(event->ctx != ctx);
1807 lockdep_assert_held(&ctx->lock);
1810 * An event which could not be activated because of
1811 * filter mismatch still needs to have its timings
1812 * maintained, otherwise bogus information is return
1813 * via read() for time_enabled, time_running:
1815 if (event->state == PERF_EVENT_STATE_INACTIVE &&
1816 !event_filter_match(event)) {
1817 delta = tstamp - event->tstamp_stopped;
1818 event->tstamp_running += delta;
1819 event->tstamp_stopped = tstamp;
1822 if (event->state != PERF_EVENT_STATE_ACTIVE)
1825 perf_pmu_disable(event->pmu);
1827 event->tstamp_stopped = tstamp;
1828 event->pmu->del(event, 0);
1830 event->state = PERF_EVENT_STATE_INACTIVE;
1831 if (event->pending_disable) {
1832 event->pending_disable = 0;
1833 event->state = PERF_EVENT_STATE_OFF;
1836 if (!is_software_event(event))
1837 cpuctx->active_oncpu--;
1838 if (!--ctx->nr_active)
1839 perf_event_ctx_deactivate(ctx);
1840 if (event->attr.freq && event->attr.sample_freq)
1842 if (event->attr.exclusive || !cpuctx->active_oncpu)
1843 cpuctx->exclusive = 0;
1845 perf_pmu_enable(event->pmu);
1849 group_sched_out(struct perf_event *group_event,
1850 struct perf_cpu_context *cpuctx,
1851 struct perf_event_context *ctx)
1853 struct perf_event *event;
1854 int state = group_event->state;
1856 perf_pmu_disable(ctx->pmu);
1858 event_sched_out(group_event, cpuctx, ctx);
1861 * Schedule out siblings (if any):
1863 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1864 event_sched_out(event, cpuctx, ctx);
1866 perf_pmu_enable(ctx->pmu);
1868 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1869 cpuctx->exclusive = 0;
1872 #define DETACH_GROUP 0x01UL
1875 * Cross CPU call to remove a performance event
1877 * We disable the event on the hardware level first. After that we
1878 * remove it from the context list.
1881 __perf_remove_from_context(struct perf_event *event,
1882 struct perf_cpu_context *cpuctx,
1883 struct perf_event_context *ctx,
1886 unsigned long flags = (unsigned long)info;
1888 event_sched_out(event, cpuctx, ctx);
1889 if (flags & DETACH_GROUP)
1890 perf_group_detach(event);
1891 list_del_event(event, ctx);
1893 if (!ctx->nr_events && ctx->is_active) {
1896 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
1897 cpuctx->task_ctx = NULL;
1903 * Remove the event from a task's (or a CPU's) list of events.
1905 * If event->ctx is a cloned context, callers must make sure that
1906 * every task struct that event->ctx->task could possibly point to
1907 * remains valid. This is OK when called from perf_release since
1908 * that only calls us on the top-level context, which can't be a clone.
1909 * When called from perf_event_exit_task, it's OK because the
1910 * context has been detached from its task.
1912 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
1914 struct perf_event_context *ctx = event->ctx;
1916 lockdep_assert_held(&ctx->mutex);
1918 event_function_call(event, __perf_remove_from_context, (void *)flags);
1921 * The above event_function_call() can NO-OP when it hits
1922 * TASK_TOMBSTONE. In that case we must already have been detached
1923 * from the context (by perf_event_exit_event()) but the grouping
1924 * might still be in-tact.
1926 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1927 if ((flags & DETACH_GROUP) &&
1928 (event->attach_state & PERF_ATTACH_GROUP)) {
1930 * Since in that case we cannot possibly be scheduled, simply
1933 raw_spin_lock_irq(&ctx->lock);
1934 perf_group_detach(event);
1935 raw_spin_unlock_irq(&ctx->lock);
1940 * Cross CPU call to disable a performance event
1942 static void __perf_event_disable(struct perf_event *event,
1943 struct perf_cpu_context *cpuctx,
1944 struct perf_event_context *ctx,
1947 if (event->state < PERF_EVENT_STATE_INACTIVE)
1950 update_context_time(ctx);
1951 update_cgrp_time_from_event(event);
1952 update_group_times(event);
1953 if (event == event->group_leader)
1954 group_sched_out(event, cpuctx, ctx);
1956 event_sched_out(event, cpuctx, ctx);
1957 event->state = PERF_EVENT_STATE_OFF;
1963 * If event->ctx is a cloned context, callers must make sure that
1964 * every task struct that event->ctx->task could possibly point to
1965 * remains valid. This condition is satisifed when called through
1966 * perf_event_for_each_child or perf_event_for_each because they
1967 * hold the top-level event's child_mutex, so any descendant that
1968 * goes to exit will block in perf_event_exit_event().
1970 * When called from perf_pending_event it's OK because event->ctx
1971 * is the current context on this CPU and preemption is disabled,
1972 * hence we can't get into perf_event_task_sched_out for this context.
1974 static void _perf_event_disable(struct perf_event *event)
1976 struct perf_event_context *ctx = event->ctx;
1978 raw_spin_lock_irq(&ctx->lock);
1979 if (event->state <= PERF_EVENT_STATE_OFF) {
1980 raw_spin_unlock_irq(&ctx->lock);
1983 raw_spin_unlock_irq(&ctx->lock);
1985 event_function_call(event, __perf_event_disable, NULL);
1988 void perf_event_disable_local(struct perf_event *event)
1990 event_function_local(event, __perf_event_disable, NULL);
1994 * Strictly speaking kernel users cannot create groups and therefore this
1995 * interface does not need the perf_event_ctx_lock() magic.
1997 void perf_event_disable(struct perf_event *event)
1999 struct perf_event_context *ctx;
2001 ctx = perf_event_ctx_lock(event);
2002 _perf_event_disable(event);
2003 perf_event_ctx_unlock(event, ctx);
2005 EXPORT_SYMBOL_GPL(perf_event_disable);
2007 void perf_event_disable_inatomic(struct perf_event *event)
2009 event->pending_disable = 1;
2010 irq_work_queue(&event->pending);
2013 static void perf_set_shadow_time(struct perf_event *event,
2014 struct perf_event_context *ctx,
2018 * use the correct time source for the time snapshot
2020 * We could get by without this by leveraging the
2021 * fact that to get to this function, the caller
2022 * has most likely already called update_context_time()
2023 * and update_cgrp_time_xx() and thus both timestamp
2024 * are identical (or very close). Given that tstamp is,
2025 * already adjusted for cgroup, we could say that:
2026 * tstamp - ctx->timestamp
2028 * tstamp - cgrp->timestamp.
2030 * Then, in perf_output_read(), the calculation would
2031 * work with no changes because:
2032 * - event is guaranteed scheduled in
2033 * - no scheduled out in between
2034 * - thus the timestamp would be the same
2036 * But this is a bit hairy.
2038 * So instead, we have an explicit cgroup call to remain
2039 * within the time time source all along. We believe it
2040 * is cleaner and simpler to understand.
2042 if (is_cgroup_event(event))
2043 perf_cgroup_set_shadow_time(event, tstamp);
2045 event->shadow_ctx_time = tstamp - ctx->timestamp;
2048 #define MAX_INTERRUPTS (~0ULL)
2050 static void perf_log_throttle(struct perf_event *event, int enable);
2051 static void perf_log_itrace_start(struct perf_event *event);
2054 event_sched_in(struct perf_event *event,
2055 struct perf_cpu_context *cpuctx,
2056 struct perf_event_context *ctx)
2058 u64 tstamp = perf_event_time(event);
2061 lockdep_assert_held(&ctx->lock);
2063 if (event->state <= PERF_EVENT_STATE_OFF)
2066 WRITE_ONCE(event->oncpu, smp_processor_id());
2068 * Order event::oncpu write to happen before the ACTIVE state
2072 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
2075 * Unthrottle events, since we scheduled we might have missed several
2076 * ticks already, also for a heavily scheduling task there is little
2077 * guarantee it'll get a tick in a timely manner.
2079 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2080 perf_log_throttle(event, 1);
2081 event->hw.interrupts = 0;
2085 * The new state must be visible before we turn it on in the hardware:
2089 perf_pmu_disable(event->pmu);
2091 perf_set_shadow_time(event, ctx, tstamp);
2093 perf_log_itrace_start(event);
2095 if (event->pmu->add(event, PERF_EF_START)) {
2096 event->state = PERF_EVENT_STATE_INACTIVE;
2102 event->tstamp_running += tstamp - event->tstamp_stopped;
2104 if (!is_software_event(event))
2105 cpuctx->active_oncpu++;
2106 if (!ctx->nr_active++)
2107 perf_event_ctx_activate(ctx);
2108 if (event->attr.freq && event->attr.sample_freq)
2111 if (event->attr.exclusive)
2112 cpuctx->exclusive = 1;
2115 perf_pmu_enable(event->pmu);
2121 group_sched_in(struct perf_event *group_event,
2122 struct perf_cpu_context *cpuctx,
2123 struct perf_event_context *ctx)
2125 struct perf_event *event, *partial_group = NULL;
2126 struct pmu *pmu = ctx->pmu;
2127 u64 now = ctx->time;
2128 bool simulate = false;
2130 if (group_event->state == PERF_EVENT_STATE_OFF)
2133 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2135 if (event_sched_in(group_event, cpuctx, ctx)) {
2136 pmu->cancel_txn(pmu);
2137 perf_mux_hrtimer_restart(cpuctx);
2142 * Schedule in siblings as one group (if any):
2144 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2145 if (event_sched_in(event, cpuctx, ctx)) {
2146 partial_group = event;
2151 if (!pmu->commit_txn(pmu))
2156 * Groups can be scheduled in as one unit only, so undo any
2157 * partial group before returning:
2158 * The events up to the failed event are scheduled out normally,
2159 * tstamp_stopped will be updated.
2161 * The failed events and the remaining siblings need to have
2162 * their timings updated as if they had gone thru event_sched_in()
2163 * and event_sched_out(). This is required to get consistent timings
2164 * across the group. This also takes care of the case where the group
2165 * could never be scheduled by ensuring tstamp_stopped is set to mark
2166 * the time the event was actually stopped, such that time delta
2167 * calculation in update_event_times() is correct.
2169 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2170 if (event == partial_group)
2174 event->tstamp_running += now - event->tstamp_stopped;
2175 event->tstamp_stopped = now;
2177 event_sched_out(event, cpuctx, ctx);
2180 event_sched_out(group_event, cpuctx, ctx);
2182 pmu->cancel_txn(pmu);
2184 perf_mux_hrtimer_restart(cpuctx);
2190 * Work out whether we can put this event group on the CPU now.
2192 static int group_can_go_on(struct perf_event *event,
2193 struct perf_cpu_context *cpuctx,
2197 * Groups consisting entirely of software events can always go on.
2199 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2202 * If an exclusive group is already on, no other hardware
2205 if (cpuctx->exclusive)
2208 * If this group is exclusive and there are already
2209 * events on the CPU, it can't go on.
2211 if (event->attr.exclusive && cpuctx->active_oncpu)
2214 * Otherwise, try to add it if all previous groups were able
2220 static void add_event_to_ctx(struct perf_event *event,
2221 struct perf_event_context *ctx)
2223 u64 tstamp = perf_event_time(event);
2225 list_add_event(event, ctx);
2226 perf_group_attach(event);
2227 event->tstamp_enabled = tstamp;
2228 event->tstamp_running = tstamp;
2229 event->tstamp_stopped = tstamp;
2232 static void ctx_sched_out(struct perf_event_context *ctx,
2233 struct perf_cpu_context *cpuctx,
2234 enum event_type_t event_type);
2236 ctx_sched_in(struct perf_event_context *ctx,
2237 struct perf_cpu_context *cpuctx,
2238 enum event_type_t event_type,
2239 struct task_struct *task);
2241 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2242 struct perf_event_context *ctx,
2243 enum event_type_t event_type)
2245 if (!cpuctx->task_ctx)
2248 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2251 ctx_sched_out(ctx, cpuctx, event_type);
2254 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2255 struct perf_event_context *ctx,
2256 struct task_struct *task)
2258 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2260 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2261 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2263 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2267 * We want to maintain the following priority of scheduling:
2268 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2269 * - task pinned (EVENT_PINNED)
2270 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2271 * - task flexible (EVENT_FLEXIBLE).
2273 * In order to avoid unscheduling and scheduling back in everything every
2274 * time an event is added, only do it for the groups of equal priority and
2277 * This can be called after a batch operation on task events, in which case
2278 * event_type is a bit mask of the types of events involved. For CPU events,
2279 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2281 static void ctx_resched(struct perf_cpu_context *cpuctx,
2282 struct perf_event_context *task_ctx,
2283 enum event_type_t event_type)
2285 enum event_type_t ctx_event_type = event_type & EVENT_ALL;
2286 bool cpu_event = !!(event_type & EVENT_CPU);
2289 * If pinned groups are involved, flexible groups also need to be
2292 if (event_type & EVENT_PINNED)
2293 event_type |= EVENT_FLEXIBLE;
2295 perf_pmu_disable(cpuctx->ctx.pmu);
2297 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2300 * Decide which cpu ctx groups to schedule out based on the types
2301 * of events that caused rescheduling:
2302 * - EVENT_CPU: schedule out corresponding groups;
2303 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2304 * - otherwise, do nothing more.
2307 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2308 else if (ctx_event_type & EVENT_PINNED)
2309 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2311 perf_event_sched_in(cpuctx, task_ctx, current);
2312 perf_pmu_enable(cpuctx->ctx.pmu);
2316 * Cross CPU call to install and enable a performance event
2318 * Very similar to remote_function() + event_function() but cannot assume that
2319 * things like ctx->is_active and cpuctx->task_ctx are set.
2321 static int __perf_install_in_context(void *info)
2323 struct perf_event *event = info;
2324 struct perf_event_context *ctx = event->ctx;
2325 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2326 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2327 bool reprogram = true;
2330 raw_spin_lock(&cpuctx->ctx.lock);
2332 raw_spin_lock(&ctx->lock);
2335 reprogram = (ctx->task == current);
2338 * If the task is running, it must be running on this CPU,
2339 * otherwise we cannot reprogram things.
2341 * If its not running, we don't care, ctx->lock will
2342 * serialize against it becoming runnable.
2344 if (task_curr(ctx->task) && !reprogram) {
2349 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2350 } else if (task_ctx) {
2351 raw_spin_lock(&task_ctx->lock);
2355 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2356 add_event_to_ctx(event, ctx);
2357 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2359 add_event_to_ctx(event, ctx);
2363 perf_ctx_unlock(cpuctx, task_ctx);
2369 * Attach a performance event to a context.
2371 * Very similar to event_function_call, see comment there.
2374 perf_install_in_context(struct perf_event_context *ctx,
2375 struct perf_event *event,
2378 struct task_struct *task = READ_ONCE(ctx->task);
2380 lockdep_assert_held(&ctx->mutex);
2382 if (event->cpu != -1)
2386 * Ensures that if we can observe event->ctx, both the event and ctx
2387 * will be 'complete'. See perf_iterate_sb_cpu().
2389 smp_store_release(&event->ctx, ctx);
2392 cpu_function_call(cpu, __perf_install_in_context, event);
2397 * Should not happen, we validate the ctx is still alive before calling.
2399 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2403 * Installing events is tricky because we cannot rely on ctx->is_active
2404 * to be set in case this is the nr_events 0 -> 1 transition.
2406 * Instead we use task_curr(), which tells us if the task is running.
2407 * However, since we use task_curr() outside of rq::lock, we can race
2408 * against the actual state. This means the result can be wrong.
2410 * If we get a false positive, we retry, this is harmless.
2412 * If we get a false negative, things are complicated. If we are after
2413 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2414 * value must be correct. If we're before, it doesn't matter since
2415 * perf_event_context_sched_in() will program the counter.
2417 * However, this hinges on the remote context switch having observed
2418 * our task->perf_event_ctxp[] store, such that it will in fact take
2419 * ctx::lock in perf_event_context_sched_in().
2421 * We do this by task_function_call(), if the IPI fails to hit the task
2422 * we know any future context switch of task must see the
2423 * perf_event_ctpx[] store.
2427 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2428 * task_cpu() load, such that if the IPI then does not find the task
2429 * running, a future context switch of that task must observe the
2434 if (!task_function_call(task, __perf_install_in_context, event))
2437 raw_spin_lock_irq(&ctx->lock);
2439 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2441 * Cannot happen because we already checked above (which also
2442 * cannot happen), and we hold ctx->mutex, which serializes us
2443 * against perf_event_exit_task_context().
2445 raw_spin_unlock_irq(&ctx->lock);
2449 * If the task is not running, ctx->lock will avoid it becoming so,
2450 * thus we can safely install the event.
2452 if (task_curr(task)) {
2453 raw_spin_unlock_irq(&ctx->lock);
2456 add_event_to_ctx(event, ctx);
2457 raw_spin_unlock_irq(&ctx->lock);
2461 * Put a event into inactive state and update time fields.
2462 * Enabling the leader of a group effectively enables all
2463 * the group members that aren't explicitly disabled, so we
2464 * have to update their ->tstamp_enabled also.
2465 * Note: this works for group members as well as group leaders
2466 * since the non-leader members' sibling_lists will be empty.
2468 static void __perf_event_mark_enabled(struct perf_event *event)
2470 struct perf_event *sub;
2471 u64 tstamp = perf_event_time(event);
2473 event->state = PERF_EVENT_STATE_INACTIVE;
2474 event->tstamp_enabled = tstamp - event->total_time_enabled;
2475 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2476 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2477 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2482 * Cross CPU call to enable a performance event
2484 static void __perf_event_enable(struct perf_event *event,
2485 struct perf_cpu_context *cpuctx,
2486 struct perf_event_context *ctx,
2489 struct perf_event *leader = event->group_leader;
2490 struct perf_event_context *task_ctx;
2492 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2493 event->state <= PERF_EVENT_STATE_ERROR)
2497 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2499 __perf_event_mark_enabled(event);
2501 if (!ctx->is_active)
2504 if (!event_filter_match(event)) {
2505 if (is_cgroup_event(event))
2506 perf_cgroup_defer_enabled(event);
2507 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2512 * If the event is in a group and isn't the group leader,
2513 * then don't put it on unless the group is on.
2515 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2516 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2520 task_ctx = cpuctx->task_ctx;
2522 WARN_ON_ONCE(task_ctx != ctx);
2524 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2530 * If event->ctx is a cloned context, callers must make sure that
2531 * every task struct that event->ctx->task could possibly point to
2532 * remains valid. This condition is satisfied when called through
2533 * perf_event_for_each_child or perf_event_for_each as described
2534 * for perf_event_disable.
2536 static void _perf_event_enable(struct perf_event *event)
2538 struct perf_event_context *ctx = event->ctx;
2540 raw_spin_lock_irq(&ctx->lock);
2541 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2542 event->state < PERF_EVENT_STATE_ERROR) {
2543 raw_spin_unlock_irq(&ctx->lock);
2548 * If the event is in error state, clear that first.
2550 * That way, if we see the event in error state below, we know that it
2551 * has gone back into error state, as distinct from the task having
2552 * been scheduled away before the cross-call arrived.
2554 if (event->state == PERF_EVENT_STATE_ERROR)
2555 event->state = PERF_EVENT_STATE_OFF;
2556 raw_spin_unlock_irq(&ctx->lock);
2558 event_function_call(event, __perf_event_enable, NULL);
2562 * See perf_event_disable();
2564 void perf_event_enable(struct perf_event *event)
2566 struct perf_event_context *ctx;
2568 ctx = perf_event_ctx_lock(event);
2569 _perf_event_enable(event);
2570 perf_event_ctx_unlock(event, ctx);
2572 EXPORT_SYMBOL_GPL(perf_event_enable);
2574 struct stop_event_data {
2575 struct perf_event *event;
2576 unsigned int restart;
2579 static int __perf_event_stop(void *info)
2581 struct stop_event_data *sd = info;
2582 struct perf_event *event = sd->event;
2584 /* if it's already INACTIVE, do nothing */
2585 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2588 /* matches smp_wmb() in event_sched_in() */
2592 * There is a window with interrupts enabled before we get here,
2593 * so we need to check again lest we try to stop another CPU's event.
2595 if (READ_ONCE(event->oncpu) != smp_processor_id())
2598 event->pmu->stop(event, PERF_EF_UPDATE);
2601 * May race with the actual stop (through perf_pmu_output_stop()),
2602 * but it is only used for events with AUX ring buffer, and such
2603 * events will refuse to restart because of rb::aux_mmap_count==0,
2604 * see comments in perf_aux_output_begin().
2606 * Since this is happening on a event-local CPU, no trace is lost
2610 event->pmu->start(event, 0);
2615 static int perf_event_stop(struct perf_event *event, int restart)
2617 struct stop_event_data sd = {
2624 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2627 /* matches smp_wmb() in event_sched_in() */
2631 * We only want to restart ACTIVE events, so if the event goes
2632 * inactive here (event->oncpu==-1), there's nothing more to do;
2633 * fall through with ret==-ENXIO.
2635 ret = cpu_function_call(READ_ONCE(event->oncpu),
2636 __perf_event_stop, &sd);
2637 } while (ret == -EAGAIN);
2643 * In order to contain the amount of racy and tricky in the address filter
2644 * configuration management, it is a two part process:
2646 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2647 * we update the addresses of corresponding vmas in
2648 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2649 * (p2) when an event is scheduled in (pmu::add), it calls
2650 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2651 * if the generation has changed since the previous call.
2653 * If (p1) happens while the event is active, we restart it to force (p2).
2655 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2656 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2658 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2659 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2661 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2664 void perf_event_addr_filters_sync(struct perf_event *event)
2666 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2668 if (!has_addr_filter(event))
2671 raw_spin_lock(&ifh->lock);
2672 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2673 event->pmu->addr_filters_sync(event);
2674 event->hw.addr_filters_gen = event->addr_filters_gen;
2676 raw_spin_unlock(&ifh->lock);
2678 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2680 static int _perf_event_refresh(struct perf_event *event, int refresh)
2683 * not supported on inherited events
2685 if (event->attr.inherit || !is_sampling_event(event))
2688 atomic_add(refresh, &event->event_limit);
2689 _perf_event_enable(event);
2695 * See perf_event_disable()
2697 int perf_event_refresh(struct perf_event *event, int refresh)
2699 struct perf_event_context *ctx;
2702 ctx = perf_event_ctx_lock(event);
2703 ret = _perf_event_refresh(event, refresh);
2704 perf_event_ctx_unlock(event, ctx);
2708 EXPORT_SYMBOL_GPL(perf_event_refresh);
2710 static void ctx_sched_out(struct perf_event_context *ctx,
2711 struct perf_cpu_context *cpuctx,
2712 enum event_type_t event_type)
2714 int is_active = ctx->is_active;
2715 struct perf_event *event;
2717 lockdep_assert_held(&ctx->lock);
2719 if (likely(!ctx->nr_events)) {
2721 * See __perf_remove_from_context().
2723 WARN_ON_ONCE(ctx->is_active);
2725 WARN_ON_ONCE(cpuctx->task_ctx);
2729 ctx->is_active &= ~event_type;
2730 if (!(ctx->is_active & EVENT_ALL))
2734 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2735 if (!ctx->is_active)
2736 cpuctx->task_ctx = NULL;
2740 * Always update time if it was set; not only when it changes.
2741 * Otherwise we can 'forget' to update time for any but the last
2742 * context we sched out. For example:
2744 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2745 * ctx_sched_out(.event_type = EVENT_PINNED)
2747 * would only update time for the pinned events.
2749 if (is_active & EVENT_TIME) {
2750 /* update (and stop) ctx time */
2751 update_context_time(ctx);
2752 update_cgrp_time_from_cpuctx(cpuctx);
2755 is_active ^= ctx->is_active; /* changed bits */
2757 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2760 perf_pmu_disable(ctx->pmu);
2761 if (is_active & EVENT_PINNED) {
2762 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2763 group_sched_out(event, cpuctx, ctx);
2766 if (is_active & EVENT_FLEXIBLE) {
2767 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2768 group_sched_out(event, cpuctx, ctx);
2770 perf_pmu_enable(ctx->pmu);
2774 * Test whether two contexts are equivalent, i.e. whether they have both been
2775 * cloned from the same version of the same context.
2777 * Equivalence is measured using a generation number in the context that is
2778 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2779 * and list_del_event().
2781 static int context_equiv(struct perf_event_context *ctx1,
2782 struct perf_event_context *ctx2)
2784 lockdep_assert_held(&ctx1->lock);
2785 lockdep_assert_held(&ctx2->lock);
2787 /* Pinning disables the swap optimization */
2788 if (ctx1->pin_count || ctx2->pin_count)
2791 /* If ctx1 is the parent of ctx2 */
2792 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2795 /* If ctx2 is the parent of ctx1 */
2796 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2800 * If ctx1 and ctx2 have the same parent; we flatten the parent
2801 * hierarchy, see perf_event_init_context().
2803 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2804 ctx1->parent_gen == ctx2->parent_gen)
2811 static void __perf_event_sync_stat(struct perf_event *event,
2812 struct perf_event *next_event)
2816 if (!event->attr.inherit_stat)
2820 * Update the event value, we cannot use perf_event_read()
2821 * because we're in the middle of a context switch and have IRQs
2822 * disabled, which upsets smp_call_function_single(), however
2823 * we know the event must be on the current CPU, therefore we
2824 * don't need to use it.
2826 switch (event->state) {
2827 case PERF_EVENT_STATE_ACTIVE:
2828 event->pmu->read(event);
2831 case PERF_EVENT_STATE_INACTIVE:
2832 update_event_times(event);
2840 * In order to keep per-task stats reliable we need to flip the event
2841 * values when we flip the contexts.
2843 value = local64_read(&next_event->count);
2844 value = local64_xchg(&event->count, value);
2845 local64_set(&next_event->count, value);
2847 swap(event->total_time_enabled, next_event->total_time_enabled);
2848 swap(event->total_time_running, next_event->total_time_running);
2851 * Since we swizzled the values, update the user visible data too.
2853 perf_event_update_userpage(event);
2854 perf_event_update_userpage(next_event);
2857 static void perf_event_sync_stat(struct perf_event_context *ctx,
2858 struct perf_event_context *next_ctx)
2860 struct perf_event *event, *next_event;
2865 update_context_time(ctx);
2867 event = list_first_entry(&ctx->event_list,
2868 struct perf_event, event_entry);
2870 next_event = list_first_entry(&next_ctx->event_list,
2871 struct perf_event, event_entry);
2873 while (&event->event_entry != &ctx->event_list &&
2874 &next_event->event_entry != &next_ctx->event_list) {
2876 __perf_event_sync_stat(event, next_event);
2878 event = list_next_entry(event, event_entry);
2879 next_event = list_next_entry(next_event, event_entry);
2883 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2884 struct task_struct *next)
2886 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2887 struct perf_event_context *next_ctx;
2888 struct perf_event_context *parent, *next_parent;
2889 struct perf_cpu_context *cpuctx;
2895 cpuctx = __get_cpu_context(ctx);
2896 if (!cpuctx->task_ctx)
2900 next_ctx = next->perf_event_ctxp[ctxn];
2904 parent = rcu_dereference(ctx->parent_ctx);
2905 next_parent = rcu_dereference(next_ctx->parent_ctx);
2907 /* If neither context have a parent context; they cannot be clones. */
2908 if (!parent && !next_parent)
2911 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2913 * Looks like the two contexts are clones, so we might be
2914 * able to optimize the context switch. We lock both
2915 * contexts and check that they are clones under the
2916 * lock (including re-checking that neither has been
2917 * uncloned in the meantime). It doesn't matter which
2918 * order we take the locks because no other cpu could
2919 * be trying to lock both of these tasks.
2921 raw_spin_lock(&ctx->lock);
2922 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2923 if (context_equiv(ctx, next_ctx)) {
2924 WRITE_ONCE(ctx->task, next);
2925 WRITE_ONCE(next_ctx->task, task);
2927 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2930 * RCU_INIT_POINTER here is safe because we've not
2931 * modified the ctx and the above modification of
2932 * ctx->task and ctx->task_ctx_data are immaterial
2933 * since those values are always verified under
2934 * ctx->lock which we're now holding.
2936 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
2937 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
2941 perf_event_sync_stat(ctx, next_ctx);
2943 raw_spin_unlock(&next_ctx->lock);
2944 raw_spin_unlock(&ctx->lock);
2950 raw_spin_lock(&ctx->lock);
2951 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
2952 raw_spin_unlock(&ctx->lock);
2956 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
2958 void perf_sched_cb_dec(struct pmu *pmu)
2960 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2962 this_cpu_dec(perf_sched_cb_usages);
2964 if (!--cpuctx->sched_cb_usage)
2965 list_del(&cpuctx->sched_cb_entry);
2969 void perf_sched_cb_inc(struct pmu *pmu)
2971 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2973 if (!cpuctx->sched_cb_usage++)
2974 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
2976 this_cpu_inc(perf_sched_cb_usages);
2980 * This function provides the context switch callback to the lower code
2981 * layer. It is invoked ONLY when the context switch callback is enabled.
2983 * This callback is relevant even to per-cpu events; for example multi event
2984 * PEBS requires this to provide PID/TID information. This requires we flush
2985 * all queued PEBS records before we context switch to a new task.
2987 static void perf_pmu_sched_task(struct task_struct *prev,
2988 struct task_struct *next,
2991 struct perf_cpu_context *cpuctx;
2997 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
2998 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3000 if (WARN_ON_ONCE(!pmu->sched_task))
3003 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3004 perf_pmu_disable(pmu);
3006 pmu->sched_task(cpuctx->task_ctx, sched_in);
3008 perf_pmu_enable(pmu);
3009 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3013 static void perf_event_switch(struct task_struct *task,
3014 struct task_struct *next_prev, bool sched_in);
3016 #define for_each_task_context_nr(ctxn) \
3017 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3020 * Called from scheduler to remove the events of the current task,
3021 * with interrupts disabled.
3023 * We stop each event and update the event value in event->count.
3025 * This does not protect us against NMI, but disable()
3026 * sets the disabled bit in the control field of event _before_
3027 * accessing the event control register. If a NMI hits, then it will
3028 * not restart the event.
3030 void __perf_event_task_sched_out(struct task_struct *task,
3031 struct task_struct *next)
3035 if (__this_cpu_read(perf_sched_cb_usages))
3036 perf_pmu_sched_task(task, next, false);
3038 if (atomic_read(&nr_switch_events))
3039 perf_event_switch(task, next, false);
3041 for_each_task_context_nr(ctxn)
3042 perf_event_context_sched_out(task, ctxn, next);
3045 * if cgroup events exist on this CPU, then we need
3046 * to check if we have to switch out PMU state.
3047 * cgroup event are system-wide mode only
3049 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3050 perf_cgroup_sched_out(task, next);
3054 * Called with IRQs disabled
3056 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3057 enum event_type_t event_type)
3059 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3063 ctx_pinned_sched_in(struct perf_event_context *ctx,
3064 struct perf_cpu_context *cpuctx)
3066 struct perf_event *event;
3068 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
3069 if (event->state <= PERF_EVENT_STATE_OFF)
3071 if (!event_filter_match(event))
3074 /* may need to reset tstamp_enabled */
3075 if (is_cgroup_event(event))
3076 perf_cgroup_mark_enabled(event, ctx);
3078 if (group_can_go_on(event, cpuctx, 1))
3079 group_sched_in(event, cpuctx, ctx);
3082 * If this pinned group hasn't been scheduled,
3083 * put it in error state.
3085 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3086 update_group_times(event);
3087 event->state = PERF_EVENT_STATE_ERROR;
3093 ctx_flexible_sched_in(struct perf_event_context *ctx,
3094 struct perf_cpu_context *cpuctx)
3096 struct perf_event *event;
3099 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
3100 /* Ignore events in OFF or ERROR state */
3101 if (event->state <= PERF_EVENT_STATE_OFF)
3104 * Listen to the 'cpu' scheduling filter constraint
3107 if (!event_filter_match(event))
3110 /* may need to reset tstamp_enabled */
3111 if (is_cgroup_event(event))
3112 perf_cgroup_mark_enabled(event, ctx);
3114 if (group_can_go_on(event, cpuctx, can_add_hw)) {
3115 if (group_sched_in(event, cpuctx, ctx))
3122 ctx_sched_in(struct perf_event_context *ctx,
3123 struct perf_cpu_context *cpuctx,
3124 enum event_type_t event_type,
3125 struct task_struct *task)
3127 int is_active = ctx->is_active;
3130 lockdep_assert_held(&ctx->lock);
3132 if (likely(!ctx->nr_events))
3135 ctx->is_active |= (event_type | EVENT_TIME);
3138 cpuctx->task_ctx = ctx;
3140 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3143 is_active ^= ctx->is_active; /* changed bits */
3145 if (is_active & EVENT_TIME) {
3146 /* start ctx time */
3148 ctx->timestamp = now;
3149 perf_cgroup_set_timestamp(task, ctx);
3153 * First go through the list and put on any pinned groups
3154 * in order to give them the best chance of going on.
3156 if (is_active & EVENT_PINNED)
3157 ctx_pinned_sched_in(ctx, cpuctx);
3159 /* Then walk through the lower prio flexible groups */
3160 if (is_active & EVENT_FLEXIBLE)
3161 ctx_flexible_sched_in(ctx, cpuctx);
3164 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3165 enum event_type_t event_type,
3166 struct task_struct *task)
3168 struct perf_event_context *ctx = &cpuctx->ctx;
3170 ctx_sched_in(ctx, cpuctx, event_type, task);
3173 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3174 struct task_struct *task)
3176 struct perf_cpu_context *cpuctx;
3178 cpuctx = __get_cpu_context(ctx);
3179 if (cpuctx->task_ctx == ctx)
3182 perf_ctx_lock(cpuctx, ctx);
3183 perf_pmu_disable(ctx->pmu);
3185 * We want to keep the following priority order:
3186 * cpu pinned (that don't need to move), task pinned,
3187 * cpu flexible, task flexible.
3189 * However, if task's ctx is not carrying any pinned
3190 * events, no need to flip the cpuctx's events around.
3192 if (!list_empty(&ctx->pinned_groups))
3193 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3194 perf_event_sched_in(cpuctx, ctx, task);
3195 perf_pmu_enable(ctx->pmu);
3196 perf_ctx_unlock(cpuctx, ctx);
3200 * Called from scheduler to add the events of the current task
3201 * with interrupts disabled.
3203 * We restore the event value and then enable it.
3205 * This does not protect us against NMI, but enable()
3206 * sets the enabled bit in the control field of event _before_
3207 * accessing the event control register. If a NMI hits, then it will
3208 * keep the event running.
3210 void __perf_event_task_sched_in(struct task_struct *prev,
3211 struct task_struct *task)
3213 struct perf_event_context *ctx;
3217 * If cgroup events exist on this CPU, then we need to check if we have
3218 * to switch in PMU state; cgroup event are system-wide mode only.
3220 * Since cgroup events are CPU events, we must schedule these in before
3221 * we schedule in the task events.
3223 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3224 perf_cgroup_sched_in(prev, task);
3226 for_each_task_context_nr(ctxn) {
3227 ctx = task->perf_event_ctxp[ctxn];
3231 perf_event_context_sched_in(ctx, task);
3234 if (atomic_read(&nr_switch_events))
3235 perf_event_switch(task, prev, true);
3237 if (__this_cpu_read(perf_sched_cb_usages))
3238 perf_pmu_sched_task(prev, task, true);
3241 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3243 u64 frequency = event->attr.sample_freq;
3244 u64 sec = NSEC_PER_SEC;
3245 u64 divisor, dividend;
3247 int count_fls, nsec_fls, frequency_fls, sec_fls;
3249 count_fls = fls64(count);
3250 nsec_fls = fls64(nsec);
3251 frequency_fls = fls64(frequency);
3255 * We got @count in @nsec, with a target of sample_freq HZ
3256 * the target period becomes:
3259 * period = -------------------
3260 * @nsec * sample_freq
3265 * Reduce accuracy by one bit such that @a and @b converge
3266 * to a similar magnitude.
3268 #define REDUCE_FLS(a, b) \
3270 if (a##_fls > b##_fls) { \
3280 * Reduce accuracy until either term fits in a u64, then proceed with
3281 * the other, so that finally we can do a u64/u64 division.
3283 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3284 REDUCE_FLS(nsec, frequency);
3285 REDUCE_FLS(sec, count);
3288 if (count_fls + sec_fls > 64) {
3289 divisor = nsec * frequency;
3291 while (count_fls + sec_fls > 64) {
3292 REDUCE_FLS(count, sec);
3296 dividend = count * sec;
3298 dividend = count * sec;
3300 while (nsec_fls + frequency_fls > 64) {
3301 REDUCE_FLS(nsec, frequency);
3305 divisor = nsec * frequency;
3311 return div64_u64(dividend, divisor);
3314 static DEFINE_PER_CPU(int, perf_throttled_count);
3315 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3317 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3319 struct hw_perf_event *hwc = &event->hw;
3320 s64 period, sample_period;
3323 period = perf_calculate_period(event, nsec, count);
3325 delta = (s64)(period - hwc->sample_period);
3326 delta = (delta + 7) / 8; /* low pass filter */
3328 sample_period = hwc->sample_period + delta;
3333 hwc->sample_period = sample_period;
3335 if (local64_read(&hwc->period_left) > 8*sample_period) {
3337 event->pmu->stop(event, PERF_EF_UPDATE);
3339 local64_set(&hwc->period_left, 0);
3342 event->pmu->start(event, PERF_EF_RELOAD);
3347 * combine freq adjustment with unthrottling to avoid two passes over the
3348 * events. At the same time, make sure, having freq events does not change
3349 * the rate of unthrottling as that would introduce bias.
3351 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3354 struct perf_event *event;
3355 struct hw_perf_event *hwc;
3356 u64 now, period = TICK_NSEC;
3360 * only need to iterate over all events iff:
3361 * - context have events in frequency mode (needs freq adjust)
3362 * - there are events to unthrottle on this cpu
3364 if (!(ctx->nr_freq || needs_unthr))
3367 raw_spin_lock(&ctx->lock);
3368 perf_pmu_disable(ctx->pmu);
3370 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3371 if (event->state != PERF_EVENT_STATE_ACTIVE)
3374 if (!event_filter_match(event))
3377 perf_pmu_disable(event->pmu);
3381 if (hwc->interrupts == MAX_INTERRUPTS) {
3382 hwc->interrupts = 0;
3383 perf_log_throttle(event, 1);
3384 event->pmu->start(event, 0);
3387 if (!event->attr.freq || !event->attr.sample_freq)
3391 * stop the event and update event->count
3393 event->pmu->stop(event, PERF_EF_UPDATE);
3395 now = local64_read(&event->count);
3396 delta = now - hwc->freq_count_stamp;
3397 hwc->freq_count_stamp = now;
3401 * reload only if value has changed
3402 * we have stopped the event so tell that
3403 * to perf_adjust_period() to avoid stopping it
3407 perf_adjust_period(event, period, delta, false);
3409 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3411 perf_pmu_enable(event->pmu);
3414 perf_pmu_enable(ctx->pmu);
3415 raw_spin_unlock(&ctx->lock);
3419 * Round-robin a context's events:
3421 static void rotate_ctx(struct perf_event_context *ctx)
3424 * Rotate the first entry last of non-pinned groups. Rotation might be
3425 * disabled by the inheritance code.
3427 if (!ctx->rotate_disable)
3428 list_rotate_left(&ctx->flexible_groups);
3431 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3433 struct perf_event_context *ctx = NULL;
3436 if (cpuctx->ctx.nr_events) {
3437 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3441 ctx = cpuctx->task_ctx;
3442 if (ctx && ctx->nr_events) {
3443 if (ctx->nr_events != ctx->nr_active)
3450 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3451 perf_pmu_disable(cpuctx->ctx.pmu);
3453 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3455 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3457 rotate_ctx(&cpuctx->ctx);
3461 perf_event_sched_in(cpuctx, ctx, current);
3463 perf_pmu_enable(cpuctx->ctx.pmu);
3464 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3470 void perf_event_task_tick(void)
3472 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3473 struct perf_event_context *ctx, *tmp;
3476 WARN_ON(!irqs_disabled());
3478 __this_cpu_inc(perf_throttled_seq);
3479 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3480 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3482 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3483 perf_adjust_freq_unthr_context(ctx, throttled);
3486 static int event_enable_on_exec(struct perf_event *event,
3487 struct perf_event_context *ctx)
3489 if (!event->attr.enable_on_exec)
3492 event->attr.enable_on_exec = 0;
3493 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3496 __perf_event_mark_enabled(event);
3502 * Enable all of a task's events that have been marked enable-on-exec.
3503 * This expects task == current.
3505 static void perf_event_enable_on_exec(int ctxn)
3507 struct perf_event_context *ctx, *clone_ctx = NULL;
3508 enum event_type_t event_type = 0;
3509 struct perf_cpu_context *cpuctx;
3510 struct perf_event *event;
3511 unsigned long flags;
3514 local_irq_save(flags);
3515 ctx = current->perf_event_ctxp[ctxn];
3516 if (!ctx || !ctx->nr_events)
3519 cpuctx = __get_cpu_context(ctx);
3520 perf_ctx_lock(cpuctx, ctx);
3521 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3522 list_for_each_entry(event, &ctx->event_list, event_entry) {
3523 enabled |= event_enable_on_exec(event, ctx);
3524 event_type |= get_event_type(event);
3528 * Unclone and reschedule this context if we enabled any event.
3531 clone_ctx = unclone_ctx(ctx);
3532 ctx_resched(cpuctx, ctx, event_type);
3534 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3536 perf_ctx_unlock(cpuctx, ctx);
3539 local_irq_restore(flags);
3545 struct perf_read_data {
3546 struct perf_event *event;
3551 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3553 u16 local_pkg, event_pkg;
3555 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3556 int local_cpu = smp_processor_id();
3558 event_pkg = topology_physical_package_id(event_cpu);
3559 local_pkg = topology_physical_package_id(local_cpu);
3561 if (event_pkg == local_pkg)
3569 * Cross CPU call to read the hardware event
3571 static void __perf_event_read(void *info)
3573 struct perf_read_data *data = info;
3574 struct perf_event *sub, *event = data->event;
3575 struct perf_event_context *ctx = event->ctx;
3576 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3577 struct pmu *pmu = event->pmu;
3580 * If this is a task context, we need to check whether it is
3581 * the current task context of this cpu. If not it has been
3582 * scheduled out before the smp call arrived. In that case
3583 * event->count would have been updated to a recent sample
3584 * when the event was scheduled out.
3586 if (ctx->task && cpuctx->task_ctx != ctx)
3589 raw_spin_lock(&ctx->lock);
3590 if (ctx->is_active) {
3591 update_context_time(ctx);
3592 update_cgrp_time_from_event(event);
3595 update_event_times(event);
3596 if (event->state != PERF_EVENT_STATE_ACTIVE)
3605 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3609 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3610 update_event_times(sub);
3611 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3613 * Use sibling's PMU rather than @event's since
3614 * sibling could be on different (eg: software) PMU.
3616 sub->pmu->read(sub);
3620 data->ret = pmu->commit_txn(pmu);
3623 raw_spin_unlock(&ctx->lock);
3626 static inline u64 perf_event_count(struct perf_event *event)
3628 if (event->pmu->count)
3629 return event->pmu->count(event);
3631 return __perf_event_count(event);
3635 * NMI-safe method to read a local event, that is an event that
3637 * - either for the current task, or for this CPU
3638 * - does not have inherit set, for inherited task events
3639 * will not be local and we cannot read them atomically
3640 * - must not have a pmu::count method
3642 u64 perf_event_read_local(struct perf_event *event)
3644 unsigned long flags;
3648 * Disabling interrupts avoids all counter scheduling (context
3649 * switches, timer based rotation and IPIs).
3651 local_irq_save(flags);
3653 /* If this is a per-task event, it must be for current */
3654 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3655 event->hw.target != current);
3657 /* If this is a per-CPU event, it must be for this CPU */
3658 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3659 event->cpu != smp_processor_id());
3662 * It must not be an event with inherit set, we cannot read
3663 * all child counters from atomic context.
3665 WARN_ON_ONCE(event->attr.inherit);
3668 * It must not have a pmu::count method, those are not
3671 WARN_ON_ONCE(event->pmu->count);
3674 * If the event is currently on this CPU, its either a per-task event,
3675 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3678 if (event->oncpu == smp_processor_id())
3679 event->pmu->read(event);
3681 val = local64_read(&event->count);
3682 local_irq_restore(flags);
3687 static int perf_event_read(struct perf_event *event, bool group)
3689 int event_cpu, ret = 0;
3692 * If event is enabled and currently active on a CPU, update the
3693 * value in the event structure:
3695 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3696 struct perf_read_data data = {
3702 event_cpu = READ_ONCE(event->oncpu);
3703 if ((unsigned)event_cpu >= nr_cpu_ids)
3707 event_cpu = __perf_event_read_cpu(event, event_cpu);
3710 * Purposely ignore the smp_call_function_single() return
3713 * If event_cpu isn't a valid CPU it means the event got
3714 * scheduled out and that will have updated the event count.
3716 * Therefore, either way, we'll have an up-to-date event count
3719 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
3722 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3723 struct perf_event_context *ctx = event->ctx;
3724 unsigned long flags;
3726 raw_spin_lock_irqsave(&ctx->lock, flags);
3728 * may read while context is not active
3729 * (e.g., thread is blocked), in that case
3730 * we cannot update context time
3732 if (ctx->is_active) {
3733 update_context_time(ctx);
3734 update_cgrp_time_from_event(event);
3737 update_group_times(event);
3739 update_event_times(event);
3740 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3747 * Initialize the perf_event context in a task_struct:
3749 static void __perf_event_init_context(struct perf_event_context *ctx)
3751 raw_spin_lock_init(&ctx->lock);
3752 mutex_init(&ctx->mutex);
3753 INIT_LIST_HEAD(&ctx->active_ctx_list);
3754 INIT_LIST_HEAD(&ctx->pinned_groups);
3755 INIT_LIST_HEAD(&ctx->flexible_groups);
3756 INIT_LIST_HEAD(&ctx->event_list);
3757 atomic_set(&ctx->refcount, 1);
3760 static struct perf_event_context *
3761 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3763 struct perf_event_context *ctx;
3765 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3769 __perf_event_init_context(ctx);
3772 get_task_struct(task);
3779 static struct task_struct *
3780 find_lively_task_by_vpid(pid_t vpid)
3782 struct task_struct *task;
3788 task = find_task_by_vpid(vpid);
3790 get_task_struct(task);
3794 return ERR_PTR(-ESRCH);
3800 * Returns a matching context with refcount and pincount.
3802 static struct perf_event_context *
3803 find_get_context(struct pmu *pmu, struct task_struct *task,
3804 struct perf_event *event)
3806 struct perf_event_context *ctx, *clone_ctx = NULL;
3807 struct perf_cpu_context *cpuctx;
3808 void *task_ctx_data = NULL;
3809 unsigned long flags;
3811 int cpu = event->cpu;
3814 /* Must be root to operate on a CPU event: */
3815 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3816 return ERR_PTR(-EACCES);
3818 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3827 ctxn = pmu->task_ctx_nr;
3831 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3832 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3833 if (!task_ctx_data) {
3840 ctx = perf_lock_task_context(task, ctxn, &flags);
3842 clone_ctx = unclone_ctx(ctx);
3845 if (task_ctx_data && !ctx->task_ctx_data) {
3846 ctx->task_ctx_data = task_ctx_data;
3847 task_ctx_data = NULL;
3849 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3854 ctx = alloc_perf_context(pmu, task);
3859 if (task_ctx_data) {
3860 ctx->task_ctx_data = task_ctx_data;
3861 task_ctx_data = NULL;
3865 mutex_lock(&task->perf_event_mutex);
3867 * If it has already passed perf_event_exit_task().
3868 * we must see PF_EXITING, it takes this mutex too.
3870 if (task->flags & PF_EXITING)
3872 else if (task->perf_event_ctxp[ctxn])
3877 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3879 mutex_unlock(&task->perf_event_mutex);
3881 if (unlikely(err)) {
3890 kfree(task_ctx_data);
3894 kfree(task_ctx_data);
3895 return ERR_PTR(err);
3898 static void perf_event_free_filter(struct perf_event *event);
3899 static void perf_event_free_bpf_prog(struct perf_event *event);
3901 static void free_event_rcu(struct rcu_head *head)
3903 struct perf_event *event;
3905 event = container_of(head, struct perf_event, rcu_head);
3907 put_pid_ns(event->ns);
3908 perf_event_free_filter(event);
3912 static void ring_buffer_attach(struct perf_event *event,
3913 struct ring_buffer *rb);
3915 static void detach_sb_event(struct perf_event *event)
3917 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
3919 raw_spin_lock(&pel->lock);
3920 list_del_rcu(&event->sb_list);
3921 raw_spin_unlock(&pel->lock);
3924 static bool is_sb_event(struct perf_event *event)
3926 struct perf_event_attr *attr = &event->attr;
3931 if (event->attach_state & PERF_ATTACH_TASK)
3934 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
3935 attr->comm || attr->comm_exec ||
3937 attr->context_switch)
3942 static void unaccount_pmu_sb_event(struct perf_event *event)
3944 if (is_sb_event(event))
3945 detach_sb_event(event);
3948 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3953 if (is_cgroup_event(event))
3954 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3957 #ifdef CONFIG_NO_HZ_FULL
3958 static DEFINE_SPINLOCK(nr_freq_lock);
3961 static void unaccount_freq_event_nohz(void)
3963 #ifdef CONFIG_NO_HZ_FULL
3964 spin_lock(&nr_freq_lock);
3965 if (atomic_dec_and_test(&nr_freq_events))
3966 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
3967 spin_unlock(&nr_freq_lock);
3971 static void unaccount_freq_event(void)
3973 if (tick_nohz_full_enabled())
3974 unaccount_freq_event_nohz();
3976 atomic_dec(&nr_freq_events);
3979 static void unaccount_event(struct perf_event *event)
3986 if (event->attach_state & PERF_ATTACH_TASK)
3988 if (event->attr.mmap || event->attr.mmap_data)
3989 atomic_dec(&nr_mmap_events);
3990 if (event->attr.comm)
3991 atomic_dec(&nr_comm_events);
3992 if (event->attr.namespaces)
3993 atomic_dec(&nr_namespaces_events);
3994 if (event->attr.task)
3995 atomic_dec(&nr_task_events);
3996 if (event->attr.freq)
3997 unaccount_freq_event();
3998 if (event->attr.context_switch) {
4000 atomic_dec(&nr_switch_events);
4002 if (is_cgroup_event(event))
4004 if (has_branch_stack(event))
4008 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4009 schedule_delayed_work(&perf_sched_work, HZ);
4012 unaccount_event_cpu(event, event->cpu);
4014 unaccount_pmu_sb_event(event);
4017 static void perf_sched_delayed(struct work_struct *work)
4019 mutex_lock(&perf_sched_mutex);
4020 if (atomic_dec_and_test(&perf_sched_count))
4021 static_branch_disable(&perf_sched_events);
4022 mutex_unlock(&perf_sched_mutex);
4026 * The following implement mutual exclusion of events on "exclusive" pmus
4027 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4028 * at a time, so we disallow creating events that might conflict, namely:
4030 * 1) cpu-wide events in the presence of per-task events,
4031 * 2) per-task events in the presence of cpu-wide events,
4032 * 3) two matching events on the same context.
4034 * The former two cases are handled in the allocation path (perf_event_alloc(),
4035 * _free_event()), the latter -- before the first perf_install_in_context().
4037 static int exclusive_event_init(struct perf_event *event)
4039 struct pmu *pmu = event->pmu;
4041 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4045 * Prevent co-existence of per-task and cpu-wide events on the
4046 * same exclusive pmu.
4048 * Negative pmu::exclusive_cnt means there are cpu-wide
4049 * events on this "exclusive" pmu, positive means there are
4052 * Since this is called in perf_event_alloc() path, event::ctx
4053 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4054 * to mean "per-task event", because unlike other attach states it
4055 * never gets cleared.
4057 if (event->attach_state & PERF_ATTACH_TASK) {
4058 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4061 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4068 static void exclusive_event_destroy(struct perf_event *event)
4070 struct pmu *pmu = event->pmu;
4072 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4075 /* see comment in exclusive_event_init() */
4076 if (event->attach_state & PERF_ATTACH_TASK)
4077 atomic_dec(&pmu->exclusive_cnt);
4079 atomic_inc(&pmu->exclusive_cnt);
4082 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4084 if ((e1->pmu == e2->pmu) &&
4085 (e1->cpu == e2->cpu ||
4092 /* Called under the same ctx::mutex as perf_install_in_context() */
4093 static bool exclusive_event_installable(struct perf_event *event,
4094 struct perf_event_context *ctx)
4096 struct perf_event *iter_event;
4097 struct pmu *pmu = event->pmu;
4099 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4102 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4103 if (exclusive_event_match(iter_event, event))
4110 static void perf_addr_filters_splice(struct perf_event *event,
4111 struct list_head *head);
4113 static void _free_event(struct perf_event *event)
4115 irq_work_sync(&event->pending);
4117 unaccount_event(event);
4121 * Can happen when we close an event with re-directed output.
4123 * Since we have a 0 refcount, perf_mmap_close() will skip
4124 * over us; possibly making our ring_buffer_put() the last.
4126 mutex_lock(&event->mmap_mutex);
4127 ring_buffer_attach(event, NULL);
4128 mutex_unlock(&event->mmap_mutex);
4131 if (is_cgroup_event(event))
4132 perf_detach_cgroup(event);
4134 if (!event->parent) {
4135 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4136 put_callchain_buffers();
4139 perf_event_free_bpf_prog(event);
4140 perf_addr_filters_splice(event, NULL);
4141 kfree(event->addr_filters_offs);
4144 event->destroy(event);
4147 put_ctx(event->ctx);
4149 exclusive_event_destroy(event);
4150 module_put(event->pmu->module);
4152 call_rcu(&event->rcu_head, free_event_rcu);
4156 * Used to free events which have a known refcount of 1, such as in error paths
4157 * where the event isn't exposed yet and inherited events.
4159 static void free_event(struct perf_event *event)
4161 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4162 "unexpected event refcount: %ld; ptr=%p\n",
4163 atomic_long_read(&event->refcount), event)) {
4164 /* leak to avoid use-after-free */
4172 * Remove user event from the owner task.
4174 static void perf_remove_from_owner(struct perf_event *event)
4176 struct task_struct *owner;
4180 * Matches the smp_store_release() in perf_event_exit_task(). If we
4181 * observe !owner it means the list deletion is complete and we can
4182 * indeed free this event, otherwise we need to serialize on
4183 * owner->perf_event_mutex.
4185 owner = lockless_dereference(event->owner);
4188 * Since delayed_put_task_struct() also drops the last
4189 * task reference we can safely take a new reference
4190 * while holding the rcu_read_lock().
4192 get_task_struct(owner);
4198 * If we're here through perf_event_exit_task() we're already
4199 * holding ctx->mutex which would be an inversion wrt. the
4200 * normal lock order.
4202 * However we can safely take this lock because its the child
4205 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4208 * We have to re-check the event->owner field, if it is cleared
4209 * we raced with perf_event_exit_task(), acquiring the mutex
4210 * ensured they're done, and we can proceed with freeing the
4214 list_del_init(&event->owner_entry);
4215 smp_store_release(&event->owner, NULL);
4217 mutex_unlock(&owner->perf_event_mutex);
4218 put_task_struct(owner);
4222 static void put_event(struct perf_event *event)
4224 if (!atomic_long_dec_and_test(&event->refcount))
4231 * Kill an event dead; while event:refcount will preserve the event
4232 * object, it will not preserve its functionality. Once the last 'user'
4233 * gives up the object, we'll destroy the thing.
4235 int perf_event_release_kernel(struct perf_event *event)
4237 struct perf_event_context *ctx = event->ctx;
4238 struct perf_event *child, *tmp;
4241 * If we got here through err_file: fput(event_file); we will not have
4242 * attached to a context yet.
4245 WARN_ON_ONCE(event->attach_state &
4246 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4250 if (!is_kernel_event(event))
4251 perf_remove_from_owner(event);
4253 ctx = perf_event_ctx_lock(event);
4254 WARN_ON_ONCE(ctx->parent_ctx);
4255 perf_remove_from_context(event, DETACH_GROUP);
4257 raw_spin_lock_irq(&ctx->lock);
4259 * Mark this event as STATE_DEAD, there is no external reference to it
4262 * Anybody acquiring event->child_mutex after the below loop _must_
4263 * also see this, most importantly inherit_event() which will avoid
4264 * placing more children on the list.
4266 * Thus this guarantees that we will in fact observe and kill _ALL_
4269 event->state = PERF_EVENT_STATE_DEAD;
4270 raw_spin_unlock_irq(&ctx->lock);
4272 perf_event_ctx_unlock(event, ctx);
4275 mutex_lock(&event->child_mutex);
4276 list_for_each_entry(child, &event->child_list, child_list) {
4279 * Cannot change, child events are not migrated, see the
4280 * comment with perf_event_ctx_lock_nested().
4282 ctx = lockless_dereference(child->ctx);
4284 * Since child_mutex nests inside ctx::mutex, we must jump
4285 * through hoops. We start by grabbing a reference on the ctx.
4287 * Since the event cannot get freed while we hold the
4288 * child_mutex, the context must also exist and have a !0
4294 * Now that we have a ctx ref, we can drop child_mutex, and
4295 * acquire ctx::mutex without fear of it going away. Then we
4296 * can re-acquire child_mutex.
4298 mutex_unlock(&event->child_mutex);
4299 mutex_lock(&ctx->mutex);
4300 mutex_lock(&event->child_mutex);
4303 * Now that we hold ctx::mutex and child_mutex, revalidate our
4304 * state, if child is still the first entry, it didn't get freed
4305 * and we can continue doing so.
4307 tmp = list_first_entry_or_null(&event->child_list,
4308 struct perf_event, child_list);
4310 perf_remove_from_context(child, DETACH_GROUP);
4311 list_del(&child->child_list);
4314 * This matches the refcount bump in inherit_event();
4315 * this can't be the last reference.
4320 mutex_unlock(&event->child_mutex);
4321 mutex_unlock(&ctx->mutex);
4325 mutex_unlock(&event->child_mutex);
4328 put_event(event); /* Must be the 'last' reference */
4331 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4334 * Called when the last reference to the file is gone.
4336 static int perf_release(struct inode *inode, struct file *file)
4338 perf_event_release_kernel(file->private_data);
4342 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4344 struct perf_event *child;
4350 mutex_lock(&event->child_mutex);
4352 (void)perf_event_read(event, false);
4353 total += perf_event_count(event);
4355 *enabled += event->total_time_enabled +
4356 atomic64_read(&event->child_total_time_enabled);
4357 *running += event->total_time_running +
4358 atomic64_read(&event->child_total_time_running);
4360 list_for_each_entry(child, &event->child_list, child_list) {
4361 (void)perf_event_read(child, false);
4362 total += perf_event_count(child);
4363 *enabled += child->total_time_enabled;
4364 *running += child->total_time_running;
4366 mutex_unlock(&event->child_mutex);
4370 EXPORT_SYMBOL_GPL(perf_event_read_value);
4372 static int __perf_read_group_add(struct perf_event *leader,
4373 u64 read_format, u64 *values)
4375 struct perf_event *sub;
4376 int n = 1; /* skip @nr */
4379 ret = perf_event_read(leader, true);
4384 * Since we co-schedule groups, {enabled,running} times of siblings
4385 * will be identical to those of the leader, so we only publish one
4388 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4389 values[n++] += leader->total_time_enabled +
4390 atomic64_read(&leader->child_total_time_enabled);
4393 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4394 values[n++] += leader->total_time_running +
4395 atomic64_read(&leader->child_total_time_running);
4399 * Write {count,id} tuples for every sibling.
4401 values[n++] += perf_event_count(leader);
4402 if (read_format & PERF_FORMAT_ID)
4403 values[n++] = primary_event_id(leader);
4405 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4406 values[n++] += perf_event_count(sub);
4407 if (read_format & PERF_FORMAT_ID)
4408 values[n++] = primary_event_id(sub);
4414 static int perf_read_group(struct perf_event *event,
4415 u64 read_format, char __user *buf)
4417 struct perf_event *leader = event->group_leader, *child;
4418 struct perf_event_context *ctx = leader->ctx;
4422 lockdep_assert_held(&ctx->mutex);
4424 values = kzalloc(event->read_size, GFP_KERNEL);
4428 values[0] = 1 + leader->nr_siblings;
4431 * By locking the child_mutex of the leader we effectively
4432 * lock the child list of all siblings.. XXX explain how.
4434 mutex_lock(&leader->child_mutex);
4436 ret = __perf_read_group_add(leader, read_format, values);
4440 list_for_each_entry(child, &leader->child_list, child_list) {
4441 ret = __perf_read_group_add(child, read_format, values);
4446 mutex_unlock(&leader->child_mutex);
4448 ret = event->read_size;
4449 if (copy_to_user(buf, values, event->read_size))
4454 mutex_unlock(&leader->child_mutex);
4460 static int perf_read_one(struct perf_event *event,
4461 u64 read_format, char __user *buf)
4463 u64 enabled, running;
4467 values[n++] = perf_event_read_value(event, &enabled, &running);
4468 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4469 values[n++] = enabled;
4470 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4471 values[n++] = running;
4472 if (read_format & PERF_FORMAT_ID)
4473 values[n++] = primary_event_id(event);
4475 if (copy_to_user(buf, values, n * sizeof(u64)))
4478 return n * sizeof(u64);
4481 static bool is_event_hup(struct perf_event *event)
4485 if (event->state > PERF_EVENT_STATE_EXIT)
4488 mutex_lock(&event->child_mutex);
4489 no_children = list_empty(&event->child_list);
4490 mutex_unlock(&event->child_mutex);
4495 * Read the performance event - simple non blocking version for now
4498 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4500 u64 read_format = event->attr.read_format;
4504 * Return end-of-file for a read on a event that is in
4505 * error state (i.e. because it was pinned but it couldn't be
4506 * scheduled on to the CPU at some point).
4508 if (event->state == PERF_EVENT_STATE_ERROR)
4511 if (count < event->read_size)
4514 WARN_ON_ONCE(event->ctx->parent_ctx);
4515 if (read_format & PERF_FORMAT_GROUP)
4516 ret = perf_read_group(event, read_format, buf);
4518 ret = perf_read_one(event, read_format, buf);
4524 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4526 struct perf_event *event = file->private_data;
4527 struct perf_event_context *ctx;
4530 ctx = perf_event_ctx_lock(event);
4531 ret = __perf_read(event, buf, count);
4532 perf_event_ctx_unlock(event, ctx);
4537 static unsigned int perf_poll(struct file *file, poll_table *wait)
4539 struct perf_event *event = file->private_data;
4540 struct ring_buffer *rb;
4541 unsigned int events = POLLHUP;
4543 poll_wait(file, &event->waitq, wait);
4545 if (is_event_hup(event))
4549 * Pin the event->rb by taking event->mmap_mutex; otherwise
4550 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4552 mutex_lock(&event->mmap_mutex);
4555 events = atomic_xchg(&rb->poll, 0);
4556 mutex_unlock(&event->mmap_mutex);
4560 static void _perf_event_reset(struct perf_event *event)
4562 (void)perf_event_read(event, false);
4563 local64_set(&event->count, 0);
4564 perf_event_update_userpage(event);
4568 * Holding the top-level event's child_mutex means that any
4569 * descendant process that has inherited this event will block
4570 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4571 * task existence requirements of perf_event_enable/disable.
4573 static void perf_event_for_each_child(struct perf_event *event,
4574 void (*func)(struct perf_event *))
4576 struct perf_event *child;
4578 WARN_ON_ONCE(event->ctx->parent_ctx);
4580 mutex_lock(&event->child_mutex);
4582 list_for_each_entry(child, &event->child_list, child_list)
4584 mutex_unlock(&event->child_mutex);
4587 static void perf_event_for_each(struct perf_event *event,
4588 void (*func)(struct perf_event *))
4590 struct perf_event_context *ctx = event->ctx;
4591 struct perf_event *sibling;
4593 lockdep_assert_held(&ctx->mutex);
4595 event = event->group_leader;
4597 perf_event_for_each_child(event, func);
4598 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4599 perf_event_for_each_child(sibling, func);
4602 static void __perf_event_period(struct perf_event *event,
4603 struct perf_cpu_context *cpuctx,
4604 struct perf_event_context *ctx,
4607 u64 value = *((u64 *)info);
4610 if (event->attr.freq) {
4611 event->attr.sample_freq = value;
4613 event->attr.sample_period = value;
4614 event->hw.sample_period = value;
4617 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4619 perf_pmu_disable(ctx->pmu);
4621 * We could be throttled; unthrottle now to avoid the tick
4622 * trying to unthrottle while we already re-started the event.
4624 if (event->hw.interrupts == MAX_INTERRUPTS) {
4625 event->hw.interrupts = 0;
4626 perf_log_throttle(event, 1);
4628 event->pmu->stop(event, PERF_EF_UPDATE);
4631 local64_set(&event->hw.period_left, 0);
4634 event->pmu->start(event, PERF_EF_RELOAD);
4635 perf_pmu_enable(ctx->pmu);
4639 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4643 if (!is_sampling_event(event))
4646 if (copy_from_user(&value, arg, sizeof(value)))
4652 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4655 event_function_call(event, __perf_event_period, &value);
4660 static const struct file_operations perf_fops;
4662 static inline int perf_fget_light(int fd, struct fd *p)
4664 struct fd f = fdget(fd);
4668 if (f.file->f_op != &perf_fops) {
4676 static int perf_event_set_output(struct perf_event *event,
4677 struct perf_event *output_event);
4678 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4679 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4681 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4683 void (*func)(struct perf_event *);
4687 case PERF_EVENT_IOC_ENABLE:
4688 func = _perf_event_enable;
4690 case PERF_EVENT_IOC_DISABLE:
4691 func = _perf_event_disable;
4693 case PERF_EVENT_IOC_RESET:
4694 func = _perf_event_reset;
4697 case PERF_EVENT_IOC_REFRESH:
4698 return _perf_event_refresh(event, arg);
4700 case PERF_EVENT_IOC_PERIOD:
4701 return perf_event_period(event, (u64 __user *)arg);
4703 case PERF_EVENT_IOC_ID:
4705 u64 id = primary_event_id(event);
4707 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4712 case PERF_EVENT_IOC_SET_OUTPUT:
4716 struct perf_event *output_event;
4718 ret = perf_fget_light(arg, &output);
4721 output_event = output.file->private_data;
4722 ret = perf_event_set_output(event, output_event);
4725 ret = perf_event_set_output(event, NULL);
4730 case PERF_EVENT_IOC_SET_FILTER:
4731 return perf_event_set_filter(event, (void __user *)arg);
4733 case PERF_EVENT_IOC_SET_BPF:
4734 return perf_event_set_bpf_prog(event, arg);
4736 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
4737 struct ring_buffer *rb;
4740 rb = rcu_dereference(event->rb);
4741 if (!rb || !rb->nr_pages) {
4745 rb_toggle_paused(rb, !!arg);
4753 if (flags & PERF_IOC_FLAG_GROUP)
4754 perf_event_for_each(event, func);
4756 perf_event_for_each_child(event, func);
4761 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4763 struct perf_event *event = file->private_data;
4764 struct perf_event_context *ctx;
4767 ctx = perf_event_ctx_lock(event);
4768 ret = _perf_ioctl(event, cmd, arg);
4769 perf_event_ctx_unlock(event, ctx);
4774 #ifdef CONFIG_COMPAT
4775 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4778 switch (_IOC_NR(cmd)) {
4779 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4780 case _IOC_NR(PERF_EVENT_IOC_ID):
4781 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4782 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4783 cmd &= ~IOCSIZE_MASK;
4784 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4788 return perf_ioctl(file, cmd, arg);
4791 # define perf_compat_ioctl NULL
4794 int perf_event_task_enable(void)
4796 struct perf_event_context *ctx;
4797 struct perf_event *event;
4799 mutex_lock(¤t->perf_event_mutex);
4800 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4801 ctx = perf_event_ctx_lock(event);
4802 perf_event_for_each_child(event, _perf_event_enable);
4803 perf_event_ctx_unlock(event, ctx);
4805 mutex_unlock(¤t->perf_event_mutex);
4810 int perf_event_task_disable(void)
4812 struct perf_event_context *ctx;
4813 struct perf_event *event;
4815 mutex_lock(¤t->perf_event_mutex);
4816 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4817 ctx = perf_event_ctx_lock(event);
4818 perf_event_for_each_child(event, _perf_event_disable);
4819 perf_event_ctx_unlock(event, ctx);
4821 mutex_unlock(¤t->perf_event_mutex);
4826 static int perf_event_index(struct perf_event *event)
4828 if (event->hw.state & PERF_HES_STOPPED)
4831 if (event->state != PERF_EVENT_STATE_ACTIVE)
4834 return event->pmu->event_idx(event);
4837 static void calc_timer_values(struct perf_event *event,
4844 *now = perf_clock();
4845 ctx_time = event->shadow_ctx_time + *now;
4846 *enabled = ctx_time - event->tstamp_enabled;
4847 *running = ctx_time - event->tstamp_running;
4850 static void perf_event_init_userpage(struct perf_event *event)
4852 struct perf_event_mmap_page *userpg;
4853 struct ring_buffer *rb;
4856 rb = rcu_dereference(event->rb);
4860 userpg = rb->user_page;
4862 /* Allow new userspace to detect that bit 0 is deprecated */
4863 userpg->cap_bit0_is_deprecated = 1;
4864 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4865 userpg->data_offset = PAGE_SIZE;
4866 userpg->data_size = perf_data_size(rb);
4872 void __weak arch_perf_update_userpage(
4873 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4878 * Callers need to ensure there can be no nesting of this function, otherwise
4879 * the seqlock logic goes bad. We can not serialize this because the arch
4880 * code calls this from NMI context.
4882 void perf_event_update_userpage(struct perf_event *event)
4884 struct perf_event_mmap_page *userpg;
4885 struct ring_buffer *rb;
4886 u64 enabled, running, now;
4889 rb = rcu_dereference(event->rb);
4894 * compute total_time_enabled, total_time_running
4895 * based on snapshot values taken when the event
4896 * was last scheduled in.
4898 * we cannot simply called update_context_time()
4899 * because of locking issue as we can be called in
4902 calc_timer_values(event, &now, &enabled, &running);
4904 userpg = rb->user_page;
4906 * Disable preemption so as to not let the corresponding user-space
4907 * spin too long if we get preempted.
4912 userpg->index = perf_event_index(event);
4913 userpg->offset = perf_event_count(event);
4915 userpg->offset -= local64_read(&event->hw.prev_count);
4917 userpg->time_enabled = enabled +
4918 atomic64_read(&event->child_total_time_enabled);
4920 userpg->time_running = running +
4921 atomic64_read(&event->child_total_time_running);
4923 arch_perf_update_userpage(event, userpg, now);
4932 static int perf_mmap_fault(struct vm_fault *vmf)
4934 struct perf_event *event = vmf->vma->vm_file->private_data;
4935 struct ring_buffer *rb;
4936 int ret = VM_FAULT_SIGBUS;
4938 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4939 if (vmf->pgoff == 0)
4945 rb = rcu_dereference(event->rb);
4949 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4952 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4956 get_page(vmf->page);
4957 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
4958 vmf->page->index = vmf->pgoff;
4967 static void ring_buffer_attach(struct perf_event *event,
4968 struct ring_buffer *rb)
4970 struct ring_buffer *old_rb = NULL;
4971 unsigned long flags;
4975 * Should be impossible, we set this when removing
4976 * event->rb_entry and wait/clear when adding event->rb_entry.
4978 WARN_ON_ONCE(event->rcu_pending);
4981 spin_lock_irqsave(&old_rb->event_lock, flags);
4982 list_del_rcu(&event->rb_entry);
4983 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4985 event->rcu_batches = get_state_synchronize_rcu();
4986 event->rcu_pending = 1;
4990 if (event->rcu_pending) {
4991 cond_synchronize_rcu(event->rcu_batches);
4992 event->rcu_pending = 0;
4995 spin_lock_irqsave(&rb->event_lock, flags);
4996 list_add_rcu(&event->rb_entry, &rb->event_list);
4997 spin_unlock_irqrestore(&rb->event_lock, flags);
5001 * Avoid racing with perf_mmap_close(AUX): stop the event
5002 * before swizzling the event::rb pointer; if it's getting
5003 * unmapped, its aux_mmap_count will be 0 and it won't
5004 * restart. See the comment in __perf_pmu_output_stop().
5006 * Data will inevitably be lost when set_output is done in
5007 * mid-air, but then again, whoever does it like this is
5008 * not in for the data anyway.
5011 perf_event_stop(event, 0);
5013 rcu_assign_pointer(event->rb, rb);
5016 ring_buffer_put(old_rb);
5018 * Since we detached before setting the new rb, so that we
5019 * could attach the new rb, we could have missed a wakeup.
5022 wake_up_all(&event->waitq);
5026 static void ring_buffer_wakeup(struct perf_event *event)
5028 struct ring_buffer *rb;
5031 rb = rcu_dereference(event->rb);
5033 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5034 wake_up_all(&event->waitq);
5039 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5041 struct ring_buffer *rb;
5044 rb = rcu_dereference(event->rb);
5046 if (!atomic_inc_not_zero(&rb->refcount))
5054 void ring_buffer_put(struct ring_buffer *rb)
5056 if (!atomic_dec_and_test(&rb->refcount))
5059 WARN_ON_ONCE(!list_empty(&rb->event_list));
5061 call_rcu(&rb->rcu_head, rb_free_rcu);
5064 static void perf_mmap_open(struct vm_area_struct *vma)
5066 struct perf_event *event = vma->vm_file->private_data;
5068 atomic_inc(&event->mmap_count);
5069 atomic_inc(&event->rb->mmap_count);
5072 atomic_inc(&event->rb->aux_mmap_count);
5074 if (event->pmu->event_mapped)
5075 event->pmu->event_mapped(event);
5078 static void perf_pmu_output_stop(struct perf_event *event);
5081 * A buffer can be mmap()ed multiple times; either directly through the same
5082 * event, or through other events by use of perf_event_set_output().
5084 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5085 * the buffer here, where we still have a VM context. This means we need
5086 * to detach all events redirecting to us.
5088 static void perf_mmap_close(struct vm_area_struct *vma)
5090 struct perf_event *event = vma->vm_file->private_data;
5092 struct ring_buffer *rb = ring_buffer_get(event);
5093 struct user_struct *mmap_user = rb->mmap_user;
5094 int mmap_locked = rb->mmap_locked;
5095 unsigned long size = perf_data_size(rb);
5097 if (event->pmu->event_unmapped)
5098 event->pmu->event_unmapped(event);
5101 * rb->aux_mmap_count will always drop before rb->mmap_count and
5102 * event->mmap_count, so it is ok to use event->mmap_mutex to
5103 * serialize with perf_mmap here.
5105 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5106 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5108 * Stop all AUX events that are writing to this buffer,
5109 * so that we can free its AUX pages and corresponding PMU
5110 * data. Note that after rb::aux_mmap_count dropped to zero,
5111 * they won't start any more (see perf_aux_output_begin()).
5113 perf_pmu_output_stop(event);
5115 /* now it's safe to free the pages */
5116 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5117 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5119 /* this has to be the last one */
5121 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5123 mutex_unlock(&event->mmap_mutex);
5126 atomic_dec(&rb->mmap_count);
5128 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5131 ring_buffer_attach(event, NULL);
5132 mutex_unlock(&event->mmap_mutex);
5134 /* If there's still other mmap()s of this buffer, we're done. */
5135 if (atomic_read(&rb->mmap_count))
5139 * No other mmap()s, detach from all other events that might redirect
5140 * into the now unreachable buffer. Somewhat complicated by the
5141 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5145 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5146 if (!atomic_long_inc_not_zero(&event->refcount)) {
5148 * This event is en-route to free_event() which will
5149 * detach it and remove it from the list.
5155 mutex_lock(&event->mmap_mutex);
5157 * Check we didn't race with perf_event_set_output() which can
5158 * swizzle the rb from under us while we were waiting to
5159 * acquire mmap_mutex.
5161 * If we find a different rb; ignore this event, a next
5162 * iteration will no longer find it on the list. We have to
5163 * still restart the iteration to make sure we're not now
5164 * iterating the wrong list.
5166 if (event->rb == rb)
5167 ring_buffer_attach(event, NULL);
5169 mutex_unlock(&event->mmap_mutex);
5173 * Restart the iteration; either we're on the wrong list or
5174 * destroyed its integrity by doing a deletion.
5181 * It could be there's still a few 0-ref events on the list; they'll
5182 * get cleaned up by free_event() -- they'll also still have their
5183 * ref on the rb and will free it whenever they are done with it.
5185 * Aside from that, this buffer is 'fully' detached and unmapped,
5186 * undo the VM accounting.
5189 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5190 vma->vm_mm->pinned_vm -= mmap_locked;
5191 free_uid(mmap_user);
5194 ring_buffer_put(rb); /* could be last */
5197 static const struct vm_operations_struct perf_mmap_vmops = {
5198 .open = perf_mmap_open,
5199 .close = perf_mmap_close, /* non mergable */
5200 .fault = perf_mmap_fault,
5201 .page_mkwrite = perf_mmap_fault,
5204 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5206 struct perf_event *event = file->private_data;
5207 unsigned long user_locked, user_lock_limit;
5208 struct user_struct *user = current_user();
5209 unsigned long locked, lock_limit;
5210 struct ring_buffer *rb = NULL;
5211 unsigned long vma_size;
5212 unsigned long nr_pages;
5213 long user_extra = 0, extra = 0;
5214 int ret = 0, flags = 0;
5217 * Don't allow mmap() of inherited per-task counters. This would
5218 * create a performance issue due to all children writing to the
5221 if (event->cpu == -1 && event->attr.inherit)
5224 if (!(vma->vm_flags & VM_SHARED))
5227 vma_size = vma->vm_end - vma->vm_start;
5229 if (vma->vm_pgoff == 0) {
5230 nr_pages = (vma_size / PAGE_SIZE) - 1;
5233 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5234 * mapped, all subsequent mappings should have the same size
5235 * and offset. Must be above the normal perf buffer.
5237 u64 aux_offset, aux_size;
5242 nr_pages = vma_size / PAGE_SIZE;
5244 mutex_lock(&event->mmap_mutex);
5251 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
5252 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
5254 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5257 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5260 /* already mapped with a different offset */
5261 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5264 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5267 /* already mapped with a different size */
5268 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5271 if (!is_power_of_2(nr_pages))
5274 if (!atomic_inc_not_zero(&rb->mmap_count))
5277 if (rb_has_aux(rb)) {
5278 atomic_inc(&rb->aux_mmap_count);
5283 atomic_set(&rb->aux_mmap_count, 1);
5284 user_extra = nr_pages;
5290 * If we have rb pages ensure they're a power-of-two number, so we
5291 * can do bitmasks instead of modulo.
5293 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5296 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5299 WARN_ON_ONCE(event->ctx->parent_ctx);
5301 mutex_lock(&event->mmap_mutex);
5303 if (event->rb->nr_pages != nr_pages) {
5308 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5310 * Raced against perf_mmap_close() through
5311 * perf_event_set_output(). Try again, hope for better
5314 mutex_unlock(&event->mmap_mutex);
5321 user_extra = nr_pages + 1;
5324 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5327 * Increase the limit linearly with more CPUs:
5329 user_lock_limit *= num_online_cpus();
5331 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5333 if (user_locked > user_lock_limit)
5334 extra = user_locked - user_lock_limit;
5336 lock_limit = rlimit(RLIMIT_MEMLOCK);
5337 lock_limit >>= PAGE_SHIFT;
5338 locked = vma->vm_mm->pinned_vm + extra;
5340 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5341 !capable(CAP_IPC_LOCK)) {
5346 WARN_ON(!rb && event->rb);
5348 if (vma->vm_flags & VM_WRITE)
5349 flags |= RING_BUFFER_WRITABLE;
5352 rb = rb_alloc(nr_pages,
5353 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5361 atomic_set(&rb->mmap_count, 1);
5362 rb->mmap_user = get_current_user();
5363 rb->mmap_locked = extra;
5365 ring_buffer_attach(event, rb);
5367 perf_event_init_userpage(event);
5368 perf_event_update_userpage(event);
5370 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5371 event->attr.aux_watermark, flags);
5373 rb->aux_mmap_locked = extra;
5378 atomic_long_add(user_extra, &user->locked_vm);
5379 vma->vm_mm->pinned_vm += extra;
5381 atomic_inc(&event->mmap_count);
5383 atomic_dec(&rb->mmap_count);
5386 mutex_unlock(&event->mmap_mutex);
5389 * Since pinned accounting is per vm we cannot allow fork() to copy our
5392 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5393 vma->vm_ops = &perf_mmap_vmops;
5395 if (event->pmu->event_mapped)
5396 event->pmu->event_mapped(event);
5401 static int perf_fasync(int fd, struct file *filp, int on)
5403 struct inode *inode = file_inode(filp);
5404 struct perf_event *event = filp->private_data;
5408 retval = fasync_helper(fd, filp, on, &event->fasync);
5409 inode_unlock(inode);
5417 static const struct file_operations perf_fops = {
5418 .llseek = no_llseek,
5419 .release = perf_release,
5422 .unlocked_ioctl = perf_ioctl,
5423 .compat_ioctl = perf_compat_ioctl,
5425 .fasync = perf_fasync,
5431 * If there's data, ensure we set the poll() state and publish everything
5432 * to user-space before waking everybody up.
5435 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5437 /* only the parent has fasync state */
5439 event = event->parent;
5440 return &event->fasync;
5443 void perf_event_wakeup(struct perf_event *event)
5445 ring_buffer_wakeup(event);
5447 if (event->pending_kill) {
5448 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5449 event->pending_kill = 0;
5453 static void perf_pending_event(struct irq_work *entry)
5455 struct perf_event *event = container_of(entry,
5456 struct perf_event, pending);
5459 rctx = perf_swevent_get_recursion_context();
5461 * If we 'fail' here, that's OK, it means recursion is already disabled
5462 * and we won't recurse 'further'.
5465 if (event->pending_disable) {
5466 event->pending_disable = 0;
5467 perf_event_disable_local(event);
5470 if (event->pending_wakeup) {
5471 event->pending_wakeup = 0;
5472 perf_event_wakeup(event);
5476 perf_swevent_put_recursion_context(rctx);
5480 * We assume there is only KVM supporting the callbacks.
5481 * Later on, we might change it to a list if there is
5482 * another virtualization implementation supporting the callbacks.
5484 struct perf_guest_info_callbacks *perf_guest_cbs;
5486 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5488 perf_guest_cbs = cbs;
5491 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5493 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5495 perf_guest_cbs = NULL;
5498 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5501 perf_output_sample_regs(struct perf_output_handle *handle,
5502 struct pt_regs *regs, u64 mask)
5505 DECLARE_BITMAP(_mask, 64);
5507 bitmap_from_u64(_mask, mask);
5508 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5511 val = perf_reg_value(regs, bit);
5512 perf_output_put(handle, val);
5516 static void perf_sample_regs_user(struct perf_regs *regs_user,
5517 struct pt_regs *regs,
5518 struct pt_regs *regs_user_copy)
5520 if (user_mode(regs)) {
5521 regs_user->abi = perf_reg_abi(current);
5522 regs_user->regs = regs;
5523 } else if (current->mm) {
5524 perf_get_regs_user(regs_user, regs, regs_user_copy);
5526 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5527 regs_user->regs = NULL;
5531 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5532 struct pt_regs *regs)
5534 regs_intr->regs = regs;
5535 regs_intr->abi = perf_reg_abi(current);
5540 * Get remaining task size from user stack pointer.
5542 * It'd be better to take stack vma map and limit this more
5543 * precisly, but there's no way to get it safely under interrupt,
5544 * so using TASK_SIZE as limit.
5546 static u64 perf_ustack_task_size(struct pt_regs *regs)
5548 unsigned long addr = perf_user_stack_pointer(regs);
5550 if (!addr || addr >= TASK_SIZE)
5553 return TASK_SIZE - addr;
5557 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5558 struct pt_regs *regs)
5562 /* No regs, no stack pointer, no dump. */
5567 * Check if we fit in with the requested stack size into the:
5569 * If we don't, we limit the size to the TASK_SIZE.
5571 * - remaining sample size
5572 * If we don't, we customize the stack size to
5573 * fit in to the remaining sample size.
5576 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5577 stack_size = min(stack_size, (u16) task_size);
5579 /* Current header size plus static size and dynamic size. */
5580 header_size += 2 * sizeof(u64);
5582 /* Do we fit in with the current stack dump size? */
5583 if ((u16) (header_size + stack_size) < header_size) {
5585 * If we overflow the maximum size for the sample,
5586 * we customize the stack dump size to fit in.
5588 stack_size = USHRT_MAX - header_size - sizeof(u64);
5589 stack_size = round_up(stack_size, sizeof(u64));
5596 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5597 struct pt_regs *regs)
5599 /* Case of a kernel thread, nothing to dump */
5602 perf_output_put(handle, size);
5611 * - the size requested by user or the best one we can fit
5612 * in to the sample max size
5614 * - user stack dump data
5616 * - the actual dumped size
5620 perf_output_put(handle, dump_size);
5623 sp = perf_user_stack_pointer(regs);
5624 rem = __output_copy_user(handle, (void *) sp, dump_size);
5625 dyn_size = dump_size - rem;
5627 perf_output_skip(handle, rem);
5630 perf_output_put(handle, dyn_size);
5634 static void __perf_event_header__init_id(struct perf_event_header *header,
5635 struct perf_sample_data *data,
5636 struct perf_event *event)
5638 u64 sample_type = event->attr.sample_type;
5640 data->type = sample_type;
5641 header->size += event->id_header_size;
5643 if (sample_type & PERF_SAMPLE_TID) {
5644 /* namespace issues */
5645 data->tid_entry.pid = perf_event_pid(event, current);
5646 data->tid_entry.tid = perf_event_tid(event, current);
5649 if (sample_type & PERF_SAMPLE_TIME)
5650 data->time = perf_event_clock(event);
5652 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5653 data->id = primary_event_id(event);
5655 if (sample_type & PERF_SAMPLE_STREAM_ID)
5656 data->stream_id = event->id;
5658 if (sample_type & PERF_SAMPLE_CPU) {
5659 data->cpu_entry.cpu = raw_smp_processor_id();
5660 data->cpu_entry.reserved = 0;
5664 void perf_event_header__init_id(struct perf_event_header *header,
5665 struct perf_sample_data *data,
5666 struct perf_event *event)
5668 if (event->attr.sample_id_all)
5669 __perf_event_header__init_id(header, data, event);
5672 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5673 struct perf_sample_data *data)
5675 u64 sample_type = data->type;
5677 if (sample_type & PERF_SAMPLE_TID)
5678 perf_output_put(handle, data->tid_entry);
5680 if (sample_type & PERF_SAMPLE_TIME)
5681 perf_output_put(handle, data->time);
5683 if (sample_type & PERF_SAMPLE_ID)
5684 perf_output_put(handle, data->id);
5686 if (sample_type & PERF_SAMPLE_STREAM_ID)
5687 perf_output_put(handle, data->stream_id);
5689 if (sample_type & PERF_SAMPLE_CPU)
5690 perf_output_put(handle, data->cpu_entry);
5692 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5693 perf_output_put(handle, data->id);
5696 void perf_event__output_id_sample(struct perf_event *event,
5697 struct perf_output_handle *handle,
5698 struct perf_sample_data *sample)
5700 if (event->attr.sample_id_all)
5701 __perf_event__output_id_sample(handle, sample);
5704 static void perf_output_read_one(struct perf_output_handle *handle,
5705 struct perf_event *event,
5706 u64 enabled, u64 running)
5708 u64 read_format = event->attr.read_format;
5712 values[n++] = perf_event_count(event);
5713 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5714 values[n++] = enabled +
5715 atomic64_read(&event->child_total_time_enabled);
5717 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5718 values[n++] = running +
5719 atomic64_read(&event->child_total_time_running);
5721 if (read_format & PERF_FORMAT_ID)
5722 values[n++] = primary_event_id(event);
5724 __output_copy(handle, values, n * sizeof(u64));
5727 static void perf_output_read_group(struct perf_output_handle *handle,
5728 struct perf_event *event,
5729 u64 enabled, u64 running)
5731 struct perf_event *leader = event->group_leader, *sub;
5732 u64 read_format = event->attr.read_format;
5736 values[n++] = 1 + leader->nr_siblings;
5738 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5739 values[n++] = enabled;
5741 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5742 values[n++] = running;
5744 if (leader != event)
5745 leader->pmu->read(leader);
5747 values[n++] = perf_event_count(leader);
5748 if (read_format & PERF_FORMAT_ID)
5749 values[n++] = primary_event_id(leader);
5751 __output_copy(handle, values, n * sizeof(u64));
5753 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5756 if ((sub != event) &&
5757 (sub->state == PERF_EVENT_STATE_ACTIVE))
5758 sub->pmu->read(sub);
5760 values[n++] = perf_event_count(sub);
5761 if (read_format & PERF_FORMAT_ID)
5762 values[n++] = primary_event_id(sub);
5764 __output_copy(handle, values, n * sizeof(u64));
5768 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5769 PERF_FORMAT_TOTAL_TIME_RUNNING)
5772 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
5774 * The problem is that its both hard and excessively expensive to iterate the
5775 * child list, not to mention that its impossible to IPI the children running
5776 * on another CPU, from interrupt/NMI context.
5778 static void perf_output_read(struct perf_output_handle *handle,
5779 struct perf_event *event)
5781 u64 enabled = 0, running = 0, now;
5782 u64 read_format = event->attr.read_format;
5785 * compute total_time_enabled, total_time_running
5786 * based on snapshot values taken when the event
5787 * was last scheduled in.
5789 * we cannot simply called update_context_time()
5790 * because of locking issue as we are called in
5793 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5794 calc_timer_values(event, &now, &enabled, &running);
5796 if (event->attr.read_format & PERF_FORMAT_GROUP)
5797 perf_output_read_group(handle, event, enabled, running);
5799 perf_output_read_one(handle, event, enabled, running);
5802 void perf_output_sample(struct perf_output_handle *handle,
5803 struct perf_event_header *header,
5804 struct perf_sample_data *data,
5805 struct perf_event *event)
5807 u64 sample_type = data->type;
5809 perf_output_put(handle, *header);
5811 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5812 perf_output_put(handle, data->id);
5814 if (sample_type & PERF_SAMPLE_IP)
5815 perf_output_put(handle, data->ip);
5817 if (sample_type & PERF_SAMPLE_TID)
5818 perf_output_put(handle, data->tid_entry);
5820 if (sample_type & PERF_SAMPLE_TIME)
5821 perf_output_put(handle, data->time);
5823 if (sample_type & PERF_SAMPLE_ADDR)
5824 perf_output_put(handle, data->addr);
5826 if (sample_type & PERF_SAMPLE_ID)
5827 perf_output_put(handle, data->id);
5829 if (sample_type & PERF_SAMPLE_STREAM_ID)
5830 perf_output_put(handle, data->stream_id);
5832 if (sample_type & PERF_SAMPLE_CPU)
5833 perf_output_put(handle, data->cpu_entry);
5835 if (sample_type & PERF_SAMPLE_PERIOD)
5836 perf_output_put(handle, data->period);
5838 if (sample_type & PERF_SAMPLE_READ)
5839 perf_output_read(handle, event);
5841 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5842 if (data->callchain) {
5845 if (data->callchain)
5846 size += data->callchain->nr;
5848 size *= sizeof(u64);
5850 __output_copy(handle, data->callchain, size);
5853 perf_output_put(handle, nr);
5857 if (sample_type & PERF_SAMPLE_RAW) {
5858 struct perf_raw_record *raw = data->raw;
5861 struct perf_raw_frag *frag = &raw->frag;
5863 perf_output_put(handle, raw->size);
5866 __output_custom(handle, frag->copy,
5867 frag->data, frag->size);
5869 __output_copy(handle, frag->data,
5872 if (perf_raw_frag_last(frag))
5877 __output_skip(handle, NULL, frag->pad);
5883 .size = sizeof(u32),
5886 perf_output_put(handle, raw);
5890 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5891 if (data->br_stack) {
5894 size = data->br_stack->nr
5895 * sizeof(struct perf_branch_entry);
5897 perf_output_put(handle, data->br_stack->nr);
5898 perf_output_copy(handle, data->br_stack->entries, size);
5901 * we always store at least the value of nr
5904 perf_output_put(handle, nr);
5908 if (sample_type & PERF_SAMPLE_REGS_USER) {
5909 u64 abi = data->regs_user.abi;
5912 * If there are no regs to dump, notice it through
5913 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5915 perf_output_put(handle, abi);
5918 u64 mask = event->attr.sample_regs_user;
5919 perf_output_sample_regs(handle,
5920 data->regs_user.regs,
5925 if (sample_type & PERF_SAMPLE_STACK_USER) {
5926 perf_output_sample_ustack(handle,
5927 data->stack_user_size,
5928 data->regs_user.regs);
5931 if (sample_type & PERF_SAMPLE_WEIGHT)
5932 perf_output_put(handle, data->weight);
5934 if (sample_type & PERF_SAMPLE_DATA_SRC)
5935 perf_output_put(handle, data->data_src.val);
5937 if (sample_type & PERF_SAMPLE_TRANSACTION)
5938 perf_output_put(handle, data->txn);
5940 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5941 u64 abi = data->regs_intr.abi;
5943 * If there are no regs to dump, notice it through
5944 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5946 perf_output_put(handle, abi);
5949 u64 mask = event->attr.sample_regs_intr;
5951 perf_output_sample_regs(handle,
5952 data->regs_intr.regs,
5957 if (!event->attr.watermark) {
5958 int wakeup_events = event->attr.wakeup_events;
5960 if (wakeup_events) {
5961 struct ring_buffer *rb = handle->rb;
5962 int events = local_inc_return(&rb->events);
5964 if (events >= wakeup_events) {
5965 local_sub(wakeup_events, &rb->events);
5966 local_inc(&rb->wakeup);
5972 void perf_prepare_sample(struct perf_event_header *header,
5973 struct perf_sample_data *data,
5974 struct perf_event *event,
5975 struct pt_regs *regs)
5977 u64 sample_type = event->attr.sample_type;
5979 header->type = PERF_RECORD_SAMPLE;
5980 header->size = sizeof(*header) + event->header_size;
5983 header->misc |= perf_misc_flags(regs);
5985 __perf_event_header__init_id(header, data, event);
5987 if (sample_type & PERF_SAMPLE_IP)
5988 data->ip = perf_instruction_pointer(regs);
5990 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5993 data->callchain = perf_callchain(event, regs);
5995 if (data->callchain)
5996 size += data->callchain->nr;
5998 header->size += size * sizeof(u64);
6001 if (sample_type & PERF_SAMPLE_RAW) {
6002 struct perf_raw_record *raw = data->raw;
6006 struct perf_raw_frag *frag = &raw->frag;
6011 if (perf_raw_frag_last(frag))
6016 size = round_up(sum + sizeof(u32), sizeof(u64));
6017 raw->size = size - sizeof(u32);
6018 frag->pad = raw->size - sum;
6023 header->size += size;
6026 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6027 int size = sizeof(u64); /* nr */
6028 if (data->br_stack) {
6029 size += data->br_stack->nr
6030 * sizeof(struct perf_branch_entry);
6032 header->size += size;
6035 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6036 perf_sample_regs_user(&data->regs_user, regs,
6037 &data->regs_user_copy);
6039 if (sample_type & PERF_SAMPLE_REGS_USER) {
6040 /* regs dump ABI info */
6041 int size = sizeof(u64);
6043 if (data->regs_user.regs) {
6044 u64 mask = event->attr.sample_regs_user;
6045 size += hweight64(mask) * sizeof(u64);
6048 header->size += size;
6051 if (sample_type & PERF_SAMPLE_STACK_USER) {
6053 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6054 * processed as the last one or have additional check added
6055 * in case new sample type is added, because we could eat
6056 * up the rest of the sample size.
6058 u16 stack_size = event->attr.sample_stack_user;
6059 u16 size = sizeof(u64);
6061 stack_size = perf_sample_ustack_size(stack_size, header->size,
6062 data->regs_user.regs);
6065 * If there is something to dump, add space for the dump
6066 * itself and for the field that tells the dynamic size,
6067 * which is how many have been actually dumped.
6070 size += sizeof(u64) + stack_size;
6072 data->stack_user_size = stack_size;
6073 header->size += size;
6076 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6077 /* regs dump ABI info */
6078 int size = sizeof(u64);
6080 perf_sample_regs_intr(&data->regs_intr, regs);
6082 if (data->regs_intr.regs) {
6083 u64 mask = event->attr.sample_regs_intr;
6085 size += hweight64(mask) * sizeof(u64);
6088 header->size += size;
6092 static void __always_inline
6093 __perf_event_output(struct perf_event *event,
6094 struct perf_sample_data *data,
6095 struct pt_regs *regs,
6096 int (*output_begin)(struct perf_output_handle *,
6097 struct perf_event *,
6100 struct perf_output_handle handle;
6101 struct perf_event_header header;
6103 /* protect the callchain buffers */
6106 perf_prepare_sample(&header, data, event, regs);
6108 if (output_begin(&handle, event, header.size))
6111 perf_output_sample(&handle, &header, data, event);
6113 perf_output_end(&handle);
6120 perf_event_output_forward(struct perf_event *event,
6121 struct perf_sample_data *data,
6122 struct pt_regs *regs)
6124 __perf_event_output(event, data, regs, perf_output_begin_forward);
6128 perf_event_output_backward(struct perf_event *event,
6129 struct perf_sample_data *data,
6130 struct pt_regs *regs)
6132 __perf_event_output(event, data, regs, perf_output_begin_backward);
6136 perf_event_output(struct perf_event *event,
6137 struct perf_sample_data *data,
6138 struct pt_regs *regs)
6140 __perf_event_output(event, data, regs, perf_output_begin);
6147 struct perf_read_event {
6148 struct perf_event_header header;
6155 perf_event_read_event(struct perf_event *event,
6156 struct task_struct *task)
6158 struct perf_output_handle handle;
6159 struct perf_sample_data sample;
6160 struct perf_read_event read_event = {
6162 .type = PERF_RECORD_READ,
6164 .size = sizeof(read_event) + event->read_size,
6166 .pid = perf_event_pid(event, task),
6167 .tid = perf_event_tid(event, task),
6171 perf_event_header__init_id(&read_event.header, &sample, event);
6172 ret = perf_output_begin(&handle, event, read_event.header.size);
6176 perf_output_put(&handle, read_event);
6177 perf_output_read(&handle, event);
6178 perf_event__output_id_sample(event, &handle, &sample);
6180 perf_output_end(&handle);
6183 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6186 perf_iterate_ctx(struct perf_event_context *ctx,
6187 perf_iterate_f output,
6188 void *data, bool all)
6190 struct perf_event *event;
6192 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6194 if (event->state < PERF_EVENT_STATE_INACTIVE)
6196 if (!event_filter_match(event))
6200 output(event, data);
6204 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6206 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6207 struct perf_event *event;
6209 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6211 * Skip events that are not fully formed yet; ensure that
6212 * if we observe event->ctx, both event and ctx will be
6213 * complete enough. See perf_install_in_context().
6215 if (!smp_load_acquire(&event->ctx))
6218 if (event->state < PERF_EVENT_STATE_INACTIVE)
6220 if (!event_filter_match(event))
6222 output(event, data);
6227 * Iterate all events that need to receive side-band events.
6229 * For new callers; ensure that account_pmu_sb_event() includes
6230 * your event, otherwise it might not get delivered.
6233 perf_iterate_sb(perf_iterate_f output, void *data,
6234 struct perf_event_context *task_ctx)
6236 struct perf_event_context *ctx;
6243 * If we have task_ctx != NULL we only notify the task context itself.
6244 * The task_ctx is set only for EXIT events before releasing task
6248 perf_iterate_ctx(task_ctx, output, data, false);
6252 perf_iterate_sb_cpu(output, data);
6254 for_each_task_context_nr(ctxn) {
6255 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6257 perf_iterate_ctx(ctx, output, data, false);
6265 * Clear all file-based filters at exec, they'll have to be
6266 * re-instated when/if these objects are mmapped again.
6268 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6270 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6271 struct perf_addr_filter *filter;
6272 unsigned int restart = 0, count = 0;
6273 unsigned long flags;
6275 if (!has_addr_filter(event))
6278 raw_spin_lock_irqsave(&ifh->lock, flags);
6279 list_for_each_entry(filter, &ifh->list, entry) {
6280 if (filter->inode) {
6281 event->addr_filters_offs[count] = 0;
6289 event->addr_filters_gen++;
6290 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6293 perf_event_stop(event, 1);
6296 void perf_event_exec(void)
6298 struct perf_event_context *ctx;
6302 for_each_task_context_nr(ctxn) {
6303 ctx = current->perf_event_ctxp[ctxn];
6307 perf_event_enable_on_exec(ctxn);
6309 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6315 struct remote_output {
6316 struct ring_buffer *rb;
6320 static void __perf_event_output_stop(struct perf_event *event, void *data)
6322 struct perf_event *parent = event->parent;
6323 struct remote_output *ro = data;
6324 struct ring_buffer *rb = ro->rb;
6325 struct stop_event_data sd = {
6329 if (!has_aux(event))
6336 * In case of inheritance, it will be the parent that links to the
6337 * ring-buffer, but it will be the child that's actually using it.
6339 * We are using event::rb to determine if the event should be stopped,
6340 * however this may race with ring_buffer_attach() (through set_output),
6341 * which will make us skip the event that actually needs to be stopped.
6342 * So ring_buffer_attach() has to stop an aux event before re-assigning
6345 if (rcu_dereference(parent->rb) == rb)
6346 ro->err = __perf_event_stop(&sd);
6349 static int __perf_pmu_output_stop(void *info)
6351 struct perf_event *event = info;
6352 struct pmu *pmu = event->pmu;
6353 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6354 struct remote_output ro = {
6359 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6360 if (cpuctx->task_ctx)
6361 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6368 static void perf_pmu_output_stop(struct perf_event *event)
6370 struct perf_event *iter;
6375 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6377 * For per-CPU events, we need to make sure that neither they
6378 * nor their children are running; for cpu==-1 events it's
6379 * sufficient to stop the event itself if it's active, since
6380 * it can't have children.
6384 cpu = READ_ONCE(iter->oncpu);
6389 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6390 if (err == -EAGAIN) {
6399 * task tracking -- fork/exit
6401 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6404 struct perf_task_event {
6405 struct task_struct *task;
6406 struct perf_event_context *task_ctx;
6409 struct perf_event_header header;
6419 static int perf_event_task_match(struct perf_event *event)
6421 return event->attr.comm || event->attr.mmap ||
6422 event->attr.mmap2 || event->attr.mmap_data ||
6426 static void perf_event_task_output(struct perf_event *event,
6429 struct perf_task_event *task_event = data;
6430 struct perf_output_handle handle;
6431 struct perf_sample_data sample;
6432 struct task_struct *task = task_event->task;
6433 int ret, size = task_event->event_id.header.size;
6435 if (!perf_event_task_match(event))
6438 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6440 ret = perf_output_begin(&handle, event,
6441 task_event->event_id.header.size);
6445 task_event->event_id.pid = perf_event_pid(event, task);
6446 task_event->event_id.ppid = perf_event_pid(event, current);
6448 task_event->event_id.tid = perf_event_tid(event, task);
6449 task_event->event_id.ptid = perf_event_tid(event, current);
6451 task_event->event_id.time = perf_event_clock(event);
6453 perf_output_put(&handle, task_event->event_id);
6455 perf_event__output_id_sample(event, &handle, &sample);
6457 perf_output_end(&handle);
6459 task_event->event_id.header.size = size;
6462 static void perf_event_task(struct task_struct *task,
6463 struct perf_event_context *task_ctx,
6466 struct perf_task_event task_event;
6468 if (!atomic_read(&nr_comm_events) &&
6469 !atomic_read(&nr_mmap_events) &&
6470 !atomic_read(&nr_task_events))
6473 task_event = (struct perf_task_event){
6475 .task_ctx = task_ctx,
6478 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6480 .size = sizeof(task_event.event_id),
6490 perf_iterate_sb(perf_event_task_output,
6495 void perf_event_fork(struct task_struct *task)
6497 perf_event_task(task, NULL, 1);
6498 perf_event_namespaces(task);
6505 struct perf_comm_event {
6506 struct task_struct *task;
6511 struct perf_event_header header;
6518 static int perf_event_comm_match(struct perf_event *event)
6520 return event->attr.comm;
6523 static void perf_event_comm_output(struct perf_event *event,
6526 struct perf_comm_event *comm_event = data;
6527 struct perf_output_handle handle;
6528 struct perf_sample_data sample;
6529 int size = comm_event->event_id.header.size;
6532 if (!perf_event_comm_match(event))
6535 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6536 ret = perf_output_begin(&handle, event,
6537 comm_event->event_id.header.size);
6542 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6543 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6545 perf_output_put(&handle, comm_event->event_id);
6546 __output_copy(&handle, comm_event->comm,
6547 comm_event->comm_size);
6549 perf_event__output_id_sample(event, &handle, &sample);
6551 perf_output_end(&handle);
6553 comm_event->event_id.header.size = size;
6556 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6558 char comm[TASK_COMM_LEN];
6561 memset(comm, 0, sizeof(comm));
6562 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6563 size = ALIGN(strlen(comm)+1, sizeof(u64));
6565 comm_event->comm = comm;
6566 comm_event->comm_size = size;
6568 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6570 perf_iterate_sb(perf_event_comm_output,
6575 void perf_event_comm(struct task_struct *task, bool exec)
6577 struct perf_comm_event comm_event;
6579 if (!atomic_read(&nr_comm_events))
6582 comm_event = (struct perf_comm_event){
6588 .type = PERF_RECORD_COMM,
6589 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6597 perf_event_comm_event(&comm_event);
6601 * namespaces tracking
6604 struct perf_namespaces_event {
6605 struct task_struct *task;
6608 struct perf_event_header header;
6613 struct perf_ns_link_info link_info[NR_NAMESPACES];
6617 static int perf_event_namespaces_match(struct perf_event *event)
6619 return event->attr.namespaces;
6622 static void perf_event_namespaces_output(struct perf_event *event,
6625 struct perf_namespaces_event *namespaces_event = data;
6626 struct perf_output_handle handle;
6627 struct perf_sample_data sample;
6630 if (!perf_event_namespaces_match(event))
6633 perf_event_header__init_id(&namespaces_event->event_id.header,
6635 ret = perf_output_begin(&handle, event,
6636 namespaces_event->event_id.header.size);
6640 namespaces_event->event_id.pid = perf_event_pid(event,
6641 namespaces_event->task);
6642 namespaces_event->event_id.tid = perf_event_tid(event,
6643 namespaces_event->task);
6645 perf_output_put(&handle, namespaces_event->event_id);
6647 perf_event__output_id_sample(event, &handle, &sample);
6649 perf_output_end(&handle);
6652 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
6653 struct task_struct *task,
6654 const struct proc_ns_operations *ns_ops)
6656 struct path ns_path;
6657 struct inode *ns_inode;
6660 error = ns_get_path(&ns_path, task, ns_ops);
6662 ns_inode = ns_path.dentry->d_inode;
6663 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
6664 ns_link_info->ino = ns_inode->i_ino;
6668 void perf_event_namespaces(struct task_struct *task)
6670 struct perf_namespaces_event namespaces_event;
6671 struct perf_ns_link_info *ns_link_info;
6673 if (!atomic_read(&nr_namespaces_events))
6676 namespaces_event = (struct perf_namespaces_event){
6680 .type = PERF_RECORD_NAMESPACES,
6682 .size = sizeof(namespaces_event.event_id),
6686 .nr_namespaces = NR_NAMESPACES,
6687 /* .link_info[NR_NAMESPACES] */
6691 ns_link_info = namespaces_event.event_id.link_info;
6693 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
6694 task, &mntns_operations);
6696 #ifdef CONFIG_USER_NS
6697 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
6698 task, &userns_operations);
6700 #ifdef CONFIG_NET_NS
6701 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
6702 task, &netns_operations);
6704 #ifdef CONFIG_UTS_NS
6705 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
6706 task, &utsns_operations);
6708 #ifdef CONFIG_IPC_NS
6709 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
6710 task, &ipcns_operations);
6712 #ifdef CONFIG_PID_NS
6713 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
6714 task, &pidns_operations);
6716 #ifdef CONFIG_CGROUPS
6717 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
6718 task, &cgroupns_operations);
6721 perf_iterate_sb(perf_event_namespaces_output,
6730 struct perf_mmap_event {
6731 struct vm_area_struct *vma;
6733 const char *file_name;
6741 struct perf_event_header header;
6751 static int perf_event_mmap_match(struct perf_event *event,
6754 struct perf_mmap_event *mmap_event = data;
6755 struct vm_area_struct *vma = mmap_event->vma;
6756 int executable = vma->vm_flags & VM_EXEC;
6758 return (!executable && event->attr.mmap_data) ||
6759 (executable && (event->attr.mmap || event->attr.mmap2));
6762 static void perf_event_mmap_output(struct perf_event *event,
6765 struct perf_mmap_event *mmap_event = data;
6766 struct perf_output_handle handle;
6767 struct perf_sample_data sample;
6768 int size = mmap_event->event_id.header.size;
6771 if (!perf_event_mmap_match(event, data))
6774 if (event->attr.mmap2) {
6775 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6776 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6777 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6778 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6779 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6780 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6781 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6784 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6785 ret = perf_output_begin(&handle, event,
6786 mmap_event->event_id.header.size);
6790 mmap_event->event_id.pid = perf_event_pid(event, current);
6791 mmap_event->event_id.tid = perf_event_tid(event, current);
6793 perf_output_put(&handle, mmap_event->event_id);
6795 if (event->attr.mmap2) {
6796 perf_output_put(&handle, mmap_event->maj);
6797 perf_output_put(&handle, mmap_event->min);
6798 perf_output_put(&handle, mmap_event->ino);
6799 perf_output_put(&handle, mmap_event->ino_generation);
6800 perf_output_put(&handle, mmap_event->prot);
6801 perf_output_put(&handle, mmap_event->flags);
6804 __output_copy(&handle, mmap_event->file_name,
6805 mmap_event->file_size);
6807 perf_event__output_id_sample(event, &handle, &sample);
6809 perf_output_end(&handle);
6811 mmap_event->event_id.header.size = size;
6814 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6816 struct vm_area_struct *vma = mmap_event->vma;
6817 struct file *file = vma->vm_file;
6818 int maj = 0, min = 0;
6819 u64 ino = 0, gen = 0;
6820 u32 prot = 0, flags = 0;
6826 if (vma->vm_flags & VM_READ)
6828 if (vma->vm_flags & VM_WRITE)
6830 if (vma->vm_flags & VM_EXEC)
6833 if (vma->vm_flags & VM_MAYSHARE)
6836 flags = MAP_PRIVATE;
6838 if (vma->vm_flags & VM_DENYWRITE)
6839 flags |= MAP_DENYWRITE;
6840 if (vma->vm_flags & VM_MAYEXEC)
6841 flags |= MAP_EXECUTABLE;
6842 if (vma->vm_flags & VM_LOCKED)
6843 flags |= MAP_LOCKED;
6844 if (vma->vm_flags & VM_HUGETLB)
6845 flags |= MAP_HUGETLB;
6848 struct inode *inode;
6851 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6857 * d_path() works from the end of the rb backwards, so we
6858 * need to add enough zero bytes after the string to handle
6859 * the 64bit alignment we do later.
6861 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6866 inode = file_inode(vma->vm_file);
6867 dev = inode->i_sb->s_dev;
6869 gen = inode->i_generation;
6875 if (vma->vm_ops && vma->vm_ops->name) {
6876 name = (char *) vma->vm_ops->name(vma);
6881 name = (char *)arch_vma_name(vma);
6885 if (vma->vm_start <= vma->vm_mm->start_brk &&
6886 vma->vm_end >= vma->vm_mm->brk) {
6890 if (vma->vm_start <= vma->vm_mm->start_stack &&
6891 vma->vm_end >= vma->vm_mm->start_stack) {
6901 strlcpy(tmp, name, sizeof(tmp));
6905 * Since our buffer works in 8 byte units we need to align our string
6906 * size to a multiple of 8. However, we must guarantee the tail end is
6907 * zero'd out to avoid leaking random bits to userspace.
6909 size = strlen(name)+1;
6910 while (!IS_ALIGNED(size, sizeof(u64)))
6911 name[size++] = '\0';
6913 mmap_event->file_name = name;
6914 mmap_event->file_size = size;
6915 mmap_event->maj = maj;
6916 mmap_event->min = min;
6917 mmap_event->ino = ino;
6918 mmap_event->ino_generation = gen;
6919 mmap_event->prot = prot;
6920 mmap_event->flags = flags;
6922 if (!(vma->vm_flags & VM_EXEC))
6923 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6925 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6927 perf_iterate_sb(perf_event_mmap_output,
6935 * Check whether inode and address range match filter criteria.
6937 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
6938 struct file *file, unsigned long offset,
6941 if (filter->inode != file_inode(file))
6944 if (filter->offset > offset + size)
6947 if (filter->offset + filter->size < offset)
6953 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
6955 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6956 struct vm_area_struct *vma = data;
6957 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
6958 struct file *file = vma->vm_file;
6959 struct perf_addr_filter *filter;
6960 unsigned int restart = 0, count = 0;
6962 if (!has_addr_filter(event))
6968 raw_spin_lock_irqsave(&ifh->lock, flags);
6969 list_for_each_entry(filter, &ifh->list, entry) {
6970 if (perf_addr_filter_match(filter, file, off,
6971 vma->vm_end - vma->vm_start)) {
6972 event->addr_filters_offs[count] = vma->vm_start;
6980 event->addr_filters_gen++;
6981 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6984 perf_event_stop(event, 1);
6988 * Adjust all task's events' filters to the new vma
6990 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
6992 struct perf_event_context *ctx;
6996 * Data tracing isn't supported yet and as such there is no need
6997 * to keep track of anything that isn't related to executable code:
6999 if (!(vma->vm_flags & VM_EXEC))
7003 for_each_task_context_nr(ctxn) {
7004 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7008 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7013 void perf_event_mmap(struct vm_area_struct *vma)
7015 struct perf_mmap_event mmap_event;
7017 if (!atomic_read(&nr_mmap_events))
7020 mmap_event = (struct perf_mmap_event){
7026 .type = PERF_RECORD_MMAP,
7027 .misc = PERF_RECORD_MISC_USER,
7032 .start = vma->vm_start,
7033 .len = vma->vm_end - vma->vm_start,
7034 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7036 /* .maj (attr_mmap2 only) */
7037 /* .min (attr_mmap2 only) */
7038 /* .ino (attr_mmap2 only) */
7039 /* .ino_generation (attr_mmap2 only) */
7040 /* .prot (attr_mmap2 only) */
7041 /* .flags (attr_mmap2 only) */
7044 perf_addr_filters_adjust(vma);
7045 perf_event_mmap_event(&mmap_event);
7048 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7049 unsigned long size, u64 flags)
7051 struct perf_output_handle handle;
7052 struct perf_sample_data sample;
7053 struct perf_aux_event {
7054 struct perf_event_header header;
7060 .type = PERF_RECORD_AUX,
7062 .size = sizeof(rec),
7070 perf_event_header__init_id(&rec.header, &sample, event);
7071 ret = perf_output_begin(&handle, event, rec.header.size);
7076 perf_output_put(&handle, rec);
7077 perf_event__output_id_sample(event, &handle, &sample);
7079 perf_output_end(&handle);
7083 * Lost/dropped samples logging
7085 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7087 struct perf_output_handle handle;
7088 struct perf_sample_data sample;
7092 struct perf_event_header header;
7094 } lost_samples_event = {
7096 .type = PERF_RECORD_LOST_SAMPLES,
7098 .size = sizeof(lost_samples_event),
7103 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7105 ret = perf_output_begin(&handle, event,
7106 lost_samples_event.header.size);
7110 perf_output_put(&handle, lost_samples_event);
7111 perf_event__output_id_sample(event, &handle, &sample);
7112 perf_output_end(&handle);
7116 * context_switch tracking
7119 struct perf_switch_event {
7120 struct task_struct *task;
7121 struct task_struct *next_prev;
7124 struct perf_event_header header;
7130 static int perf_event_switch_match(struct perf_event *event)
7132 return event->attr.context_switch;
7135 static void perf_event_switch_output(struct perf_event *event, void *data)
7137 struct perf_switch_event *se = data;
7138 struct perf_output_handle handle;
7139 struct perf_sample_data sample;
7142 if (!perf_event_switch_match(event))
7145 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7146 if (event->ctx->task) {
7147 se->event_id.header.type = PERF_RECORD_SWITCH;
7148 se->event_id.header.size = sizeof(se->event_id.header);
7150 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7151 se->event_id.header.size = sizeof(se->event_id);
7152 se->event_id.next_prev_pid =
7153 perf_event_pid(event, se->next_prev);
7154 se->event_id.next_prev_tid =
7155 perf_event_tid(event, se->next_prev);
7158 perf_event_header__init_id(&se->event_id.header, &sample, event);
7160 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7164 if (event->ctx->task)
7165 perf_output_put(&handle, se->event_id.header);
7167 perf_output_put(&handle, se->event_id);
7169 perf_event__output_id_sample(event, &handle, &sample);
7171 perf_output_end(&handle);
7174 static void perf_event_switch(struct task_struct *task,
7175 struct task_struct *next_prev, bool sched_in)
7177 struct perf_switch_event switch_event;
7179 /* N.B. caller checks nr_switch_events != 0 */
7181 switch_event = (struct perf_switch_event){
7183 .next_prev = next_prev,
7187 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7190 /* .next_prev_pid */
7191 /* .next_prev_tid */
7195 perf_iterate_sb(perf_event_switch_output,
7201 * IRQ throttle logging
7204 static void perf_log_throttle(struct perf_event *event, int enable)
7206 struct perf_output_handle handle;
7207 struct perf_sample_data sample;
7211 struct perf_event_header header;
7215 } throttle_event = {
7217 .type = PERF_RECORD_THROTTLE,
7219 .size = sizeof(throttle_event),
7221 .time = perf_event_clock(event),
7222 .id = primary_event_id(event),
7223 .stream_id = event->id,
7227 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7229 perf_event_header__init_id(&throttle_event.header, &sample, event);
7231 ret = perf_output_begin(&handle, event,
7232 throttle_event.header.size);
7236 perf_output_put(&handle, throttle_event);
7237 perf_event__output_id_sample(event, &handle, &sample);
7238 perf_output_end(&handle);
7241 static void perf_log_itrace_start(struct perf_event *event)
7243 struct perf_output_handle handle;
7244 struct perf_sample_data sample;
7245 struct perf_aux_event {
7246 struct perf_event_header header;
7253 event = event->parent;
7255 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7256 event->hw.itrace_started)
7259 rec.header.type = PERF_RECORD_ITRACE_START;
7260 rec.header.misc = 0;
7261 rec.header.size = sizeof(rec);
7262 rec.pid = perf_event_pid(event, current);
7263 rec.tid = perf_event_tid(event, current);
7265 perf_event_header__init_id(&rec.header, &sample, event);
7266 ret = perf_output_begin(&handle, event, rec.header.size);
7271 perf_output_put(&handle, rec);
7272 perf_event__output_id_sample(event, &handle, &sample);
7274 perf_output_end(&handle);
7278 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7280 struct hw_perf_event *hwc = &event->hw;
7284 seq = __this_cpu_read(perf_throttled_seq);
7285 if (seq != hwc->interrupts_seq) {
7286 hwc->interrupts_seq = seq;
7287 hwc->interrupts = 1;
7290 if (unlikely(throttle
7291 && hwc->interrupts >= max_samples_per_tick)) {
7292 __this_cpu_inc(perf_throttled_count);
7293 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7294 hwc->interrupts = MAX_INTERRUPTS;
7295 perf_log_throttle(event, 0);
7300 if (event->attr.freq) {
7301 u64 now = perf_clock();
7302 s64 delta = now - hwc->freq_time_stamp;
7304 hwc->freq_time_stamp = now;
7306 if (delta > 0 && delta < 2*TICK_NSEC)
7307 perf_adjust_period(event, delta, hwc->last_period, true);
7313 int perf_event_account_interrupt(struct perf_event *event)
7315 return __perf_event_account_interrupt(event, 1);
7319 * Generic event overflow handling, sampling.
7322 static int __perf_event_overflow(struct perf_event *event,
7323 int throttle, struct perf_sample_data *data,
7324 struct pt_regs *regs)
7326 int events = atomic_read(&event->event_limit);
7330 * Non-sampling counters might still use the PMI to fold short
7331 * hardware counters, ignore those.
7333 if (unlikely(!is_sampling_event(event)))
7336 ret = __perf_event_account_interrupt(event, throttle);
7339 * XXX event_limit might not quite work as expected on inherited
7343 event->pending_kill = POLL_IN;
7344 if (events && atomic_dec_and_test(&event->event_limit)) {
7346 event->pending_kill = POLL_HUP;
7348 perf_event_disable_inatomic(event);
7351 READ_ONCE(event->overflow_handler)(event, data, regs);
7353 if (*perf_event_fasync(event) && event->pending_kill) {
7354 event->pending_wakeup = 1;
7355 irq_work_queue(&event->pending);
7361 int perf_event_overflow(struct perf_event *event,
7362 struct perf_sample_data *data,
7363 struct pt_regs *regs)
7365 return __perf_event_overflow(event, 1, data, regs);
7369 * Generic software event infrastructure
7372 struct swevent_htable {
7373 struct swevent_hlist *swevent_hlist;
7374 struct mutex hlist_mutex;
7377 /* Recursion avoidance in each contexts */
7378 int recursion[PERF_NR_CONTEXTS];
7381 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7384 * We directly increment event->count and keep a second value in
7385 * event->hw.period_left to count intervals. This period event
7386 * is kept in the range [-sample_period, 0] so that we can use the
7390 u64 perf_swevent_set_period(struct perf_event *event)
7392 struct hw_perf_event *hwc = &event->hw;
7393 u64 period = hwc->last_period;
7397 hwc->last_period = hwc->sample_period;
7400 old = val = local64_read(&hwc->period_left);
7404 nr = div64_u64(period + val, period);
7405 offset = nr * period;
7407 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7413 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7414 struct perf_sample_data *data,
7415 struct pt_regs *regs)
7417 struct hw_perf_event *hwc = &event->hw;
7421 overflow = perf_swevent_set_period(event);
7423 if (hwc->interrupts == MAX_INTERRUPTS)
7426 for (; overflow; overflow--) {
7427 if (__perf_event_overflow(event, throttle,
7430 * We inhibit the overflow from happening when
7431 * hwc->interrupts == MAX_INTERRUPTS.
7439 static void perf_swevent_event(struct perf_event *event, u64 nr,
7440 struct perf_sample_data *data,
7441 struct pt_regs *regs)
7443 struct hw_perf_event *hwc = &event->hw;
7445 local64_add(nr, &event->count);
7450 if (!is_sampling_event(event))
7453 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7455 return perf_swevent_overflow(event, 1, data, regs);
7457 data->period = event->hw.last_period;
7459 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7460 return perf_swevent_overflow(event, 1, data, regs);
7462 if (local64_add_negative(nr, &hwc->period_left))
7465 perf_swevent_overflow(event, 0, data, regs);
7468 static int perf_exclude_event(struct perf_event *event,
7469 struct pt_regs *regs)
7471 if (event->hw.state & PERF_HES_STOPPED)
7475 if (event->attr.exclude_user && user_mode(regs))
7478 if (event->attr.exclude_kernel && !user_mode(regs))
7485 static int perf_swevent_match(struct perf_event *event,
7486 enum perf_type_id type,
7488 struct perf_sample_data *data,
7489 struct pt_regs *regs)
7491 if (event->attr.type != type)
7494 if (event->attr.config != event_id)
7497 if (perf_exclude_event(event, regs))
7503 static inline u64 swevent_hash(u64 type, u32 event_id)
7505 u64 val = event_id | (type << 32);
7507 return hash_64(val, SWEVENT_HLIST_BITS);
7510 static inline struct hlist_head *
7511 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7513 u64 hash = swevent_hash(type, event_id);
7515 return &hlist->heads[hash];
7518 /* For the read side: events when they trigger */
7519 static inline struct hlist_head *
7520 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7522 struct swevent_hlist *hlist;
7524 hlist = rcu_dereference(swhash->swevent_hlist);
7528 return __find_swevent_head(hlist, type, event_id);
7531 /* For the event head insertion and removal in the hlist */
7532 static inline struct hlist_head *
7533 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7535 struct swevent_hlist *hlist;
7536 u32 event_id = event->attr.config;
7537 u64 type = event->attr.type;
7540 * Event scheduling is always serialized against hlist allocation
7541 * and release. Which makes the protected version suitable here.
7542 * The context lock guarantees that.
7544 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7545 lockdep_is_held(&event->ctx->lock));
7549 return __find_swevent_head(hlist, type, event_id);
7552 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7554 struct perf_sample_data *data,
7555 struct pt_regs *regs)
7557 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7558 struct perf_event *event;
7559 struct hlist_head *head;
7562 head = find_swevent_head_rcu(swhash, type, event_id);
7566 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7567 if (perf_swevent_match(event, type, event_id, data, regs))
7568 perf_swevent_event(event, nr, data, regs);
7574 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
7576 int perf_swevent_get_recursion_context(void)
7578 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7580 return get_recursion_context(swhash->recursion);
7582 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
7584 void perf_swevent_put_recursion_context(int rctx)
7586 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7588 put_recursion_context(swhash->recursion, rctx);
7591 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7593 struct perf_sample_data data;
7595 if (WARN_ON_ONCE(!regs))
7598 perf_sample_data_init(&data, addr, 0);
7599 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
7602 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
7606 preempt_disable_notrace();
7607 rctx = perf_swevent_get_recursion_context();
7608 if (unlikely(rctx < 0))
7611 ___perf_sw_event(event_id, nr, regs, addr);
7613 perf_swevent_put_recursion_context(rctx);
7615 preempt_enable_notrace();
7618 static void perf_swevent_read(struct perf_event *event)
7622 static int perf_swevent_add(struct perf_event *event, int flags)
7624 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7625 struct hw_perf_event *hwc = &event->hw;
7626 struct hlist_head *head;
7628 if (is_sampling_event(event)) {
7629 hwc->last_period = hwc->sample_period;
7630 perf_swevent_set_period(event);
7633 hwc->state = !(flags & PERF_EF_START);
7635 head = find_swevent_head(swhash, event);
7636 if (WARN_ON_ONCE(!head))
7639 hlist_add_head_rcu(&event->hlist_entry, head);
7640 perf_event_update_userpage(event);
7645 static void perf_swevent_del(struct perf_event *event, int flags)
7647 hlist_del_rcu(&event->hlist_entry);
7650 static void perf_swevent_start(struct perf_event *event, int flags)
7652 event->hw.state = 0;
7655 static void perf_swevent_stop(struct perf_event *event, int flags)
7657 event->hw.state = PERF_HES_STOPPED;
7660 /* Deref the hlist from the update side */
7661 static inline struct swevent_hlist *
7662 swevent_hlist_deref(struct swevent_htable *swhash)
7664 return rcu_dereference_protected(swhash->swevent_hlist,
7665 lockdep_is_held(&swhash->hlist_mutex));
7668 static void swevent_hlist_release(struct swevent_htable *swhash)
7670 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
7675 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
7676 kfree_rcu(hlist, rcu_head);
7679 static void swevent_hlist_put_cpu(int cpu)
7681 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7683 mutex_lock(&swhash->hlist_mutex);
7685 if (!--swhash->hlist_refcount)
7686 swevent_hlist_release(swhash);
7688 mutex_unlock(&swhash->hlist_mutex);
7691 static void swevent_hlist_put(void)
7695 for_each_possible_cpu(cpu)
7696 swevent_hlist_put_cpu(cpu);
7699 static int swevent_hlist_get_cpu(int cpu)
7701 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
7704 mutex_lock(&swhash->hlist_mutex);
7705 if (!swevent_hlist_deref(swhash) &&
7706 cpumask_test_cpu(cpu, perf_online_mask)) {
7707 struct swevent_hlist *hlist;
7709 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
7714 rcu_assign_pointer(swhash->swevent_hlist, hlist);
7716 swhash->hlist_refcount++;
7718 mutex_unlock(&swhash->hlist_mutex);
7723 static int swevent_hlist_get(void)
7725 int err, cpu, failed_cpu;
7727 mutex_lock(&pmus_lock);
7728 for_each_possible_cpu(cpu) {
7729 err = swevent_hlist_get_cpu(cpu);
7735 mutex_unlock(&pmus_lock);
7738 for_each_possible_cpu(cpu) {
7739 if (cpu == failed_cpu)
7741 swevent_hlist_put_cpu(cpu);
7743 mutex_unlock(&pmus_lock);
7747 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7749 static void sw_perf_event_destroy(struct perf_event *event)
7751 u64 event_id = event->attr.config;
7753 WARN_ON(event->parent);
7755 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7756 swevent_hlist_put();
7759 static int perf_swevent_init(struct perf_event *event)
7761 u64 event_id = event->attr.config;
7763 if (event->attr.type != PERF_TYPE_SOFTWARE)
7767 * no branch sampling for software events
7769 if (has_branch_stack(event))
7773 case PERF_COUNT_SW_CPU_CLOCK:
7774 case PERF_COUNT_SW_TASK_CLOCK:
7781 if (event_id >= PERF_COUNT_SW_MAX)
7784 if (!event->parent) {
7787 err = swevent_hlist_get();
7791 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7792 event->destroy = sw_perf_event_destroy;
7798 static struct pmu perf_swevent = {
7799 .task_ctx_nr = perf_sw_context,
7801 .capabilities = PERF_PMU_CAP_NO_NMI,
7803 .event_init = perf_swevent_init,
7804 .add = perf_swevent_add,
7805 .del = perf_swevent_del,
7806 .start = perf_swevent_start,
7807 .stop = perf_swevent_stop,
7808 .read = perf_swevent_read,
7811 #ifdef CONFIG_EVENT_TRACING
7813 static int perf_tp_filter_match(struct perf_event *event,
7814 struct perf_sample_data *data)
7816 void *record = data->raw->frag.data;
7818 /* only top level events have filters set */
7820 event = event->parent;
7822 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7827 static int perf_tp_event_match(struct perf_event *event,
7828 struct perf_sample_data *data,
7829 struct pt_regs *regs)
7831 if (event->hw.state & PERF_HES_STOPPED)
7834 * All tracepoints are from kernel-space.
7836 if (event->attr.exclude_kernel)
7839 if (!perf_tp_filter_match(event, data))
7845 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
7846 struct trace_event_call *call, u64 count,
7847 struct pt_regs *regs, struct hlist_head *head,
7848 struct task_struct *task)
7850 struct bpf_prog *prog = call->prog;
7853 *(struct pt_regs **)raw_data = regs;
7854 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) {
7855 perf_swevent_put_recursion_context(rctx);
7859 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
7862 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
7864 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
7865 struct pt_regs *regs, struct hlist_head *head, int rctx,
7866 struct task_struct *task)
7868 struct perf_sample_data data;
7869 struct perf_event *event;
7871 struct perf_raw_record raw = {
7878 perf_sample_data_init(&data, 0, 0);
7881 perf_trace_buf_update(record, event_type);
7883 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7884 if (perf_tp_event_match(event, &data, regs))
7885 perf_swevent_event(event, count, &data, regs);
7889 * If we got specified a target task, also iterate its context and
7890 * deliver this event there too.
7892 if (task && task != current) {
7893 struct perf_event_context *ctx;
7894 struct trace_entry *entry = record;
7897 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7901 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7902 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7904 if (event->attr.config != entry->type)
7906 if (perf_tp_event_match(event, &data, regs))
7907 perf_swevent_event(event, count, &data, regs);
7913 perf_swevent_put_recursion_context(rctx);
7915 EXPORT_SYMBOL_GPL(perf_tp_event);
7917 static void tp_perf_event_destroy(struct perf_event *event)
7919 perf_trace_destroy(event);
7922 static int perf_tp_event_init(struct perf_event *event)
7926 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7930 * no branch sampling for tracepoint events
7932 if (has_branch_stack(event))
7935 err = perf_trace_init(event);
7939 event->destroy = tp_perf_event_destroy;
7944 static struct pmu perf_tracepoint = {
7945 .task_ctx_nr = perf_sw_context,
7947 .event_init = perf_tp_event_init,
7948 .add = perf_trace_add,
7949 .del = perf_trace_del,
7950 .start = perf_swevent_start,
7951 .stop = perf_swevent_stop,
7952 .read = perf_swevent_read,
7955 static inline void perf_tp_register(void)
7957 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7960 static void perf_event_free_filter(struct perf_event *event)
7962 ftrace_profile_free_filter(event);
7965 #ifdef CONFIG_BPF_SYSCALL
7966 static void bpf_overflow_handler(struct perf_event *event,
7967 struct perf_sample_data *data,
7968 struct pt_regs *regs)
7970 struct bpf_perf_event_data_kern ctx = {
7977 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
7980 ret = BPF_PROG_RUN(event->prog, &ctx);
7983 __this_cpu_dec(bpf_prog_active);
7988 event->orig_overflow_handler(event, data, regs);
7991 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
7993 struct bpf_prog *prog;
7995 if (event->overflow_handler_context)
7996 /* hw breakpoint or kernel counter */
8002 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8004 return PTR_ERR(prog);
8007 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8008 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8012 static void perf_event_free_bpf_handler(struct perf_event *event)
8014 struct bpf_prog *prog = event->prog;
8019 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8024 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8028 static void perf_event_free_bpf_handler(struct perf_event *event)
8033 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8035 bool is_kprobe, is_tracepoint;
8036 struct bpf_prog *prog;
8038 if (event->attr.type == PERF_TYPE_HARDWARE ||
8039 event->attr.type == PERF_TYPE_SOFTWARE)
8040 return perf_event_set_bpf_handler(event, prog_fd);
8042 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8045 if (event->tp_event->prog)
8048 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8049 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8050 if (!is_kprobe && !is_tracepoint)
8051 /* bpf programs can only be attached to u/kprobe or tracepoint */
8054 prog = bpf_prog_get(prog_fd);
8056 return PTR_ERR(prog);
8058 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8059 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8060 /* valid fd, but invalid bpf program type */
8065 if (is_tracepoint) {
8066 int off = trace_event_get_offsets(event->tp_event);
8068 if (prog->aux->max_ctx_offset > off) {
8073 event->tp_event->prog = prog;
8078 static void perf_event_free_bpf_prog(struct perf_event *event)
8080 struct bpf_prog *prog;
8082 perf_event_free_bpf_handler(event);
8084 if (!event->tp_event)
8087 prog = event->tp_event->prog;
8089 event->tp_event->prog = NULL;
8096 static inline void perf_tp_register(void)
8100 static void perf_event_free_filter(struct perf_event *event)
8104 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8109 static void perf_event_free_bpf_prog(struct perf_event *event)
8112 #endif /* CONFIG_EVENT_TRACING */
8114 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8115 void perf_bp_event(struct perf_event *bp, void *data)
8117 struct perf_sample_data sample;
8118 struct pt_regs *regs = data;
8120 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8122 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8123 perf_swevent_event(bp, 1, &sample, regs);
8128 * Allocate a new address filter
8130 static struct perf_addr_filter *
8131 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8133 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8134 struct perf_addr_filter *filter;
8136 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8140 INIT_LIST_HEAD(&filter->entry);
8141 list_add_tail(&filter->entry, filters);
8146 static void free_filters_list(struct list_head *filters)
8148 struct perf_addr_filter *filter, *iter;
8150 list_for_each_entry_safe(filter, iter, filters, entry) {
8152 iput(filter->inode);
8153 list_del(&filter->entry);
8159 * Free existing address filters and optionally install new ones
8161 static void perf_addr_filters_splice(struct perf_event *event,
8162 struct list_head *head)
8164 unsigned long flags;
8167 if (!has_addr_filter(event))
8170 /* don't bother with children, they don't have their own filters */
8174 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8176 list_splice_init(&event->addr_filters.list, &list);
8178 list_splice(head, &event->addr_filters.list);
8180 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8182 free_filters_list(&list);
8186 * Scan through mm's vmas and see if one of them matches the
8187 * @filter; if so, adjust filter's address range.
8188 * Called with mm::mmap_sem down for reading.
8190 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8191 struct mm_struct *mm)
8193 struct vm_area_struct *vma;
8195 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8196 struct file *file = vma->vm_file;
8197 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8198 unsigned long vma_size = vma->vm_end - vma->vm_start;
8203 if (!perf_addr_filter_match(filter, file, off, vma_size))
8206 return vma->vm_start;
8213 * Update event's address range filters based on the
8214 * task's existing mappings, if any.
8216 static void perf_event_addr_filters_apply(struct perf_event *event)
8218 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8219 struct task_struct *task = READ_ONCE(event->ctx->task);
8220 struct perf_addr_filter *filter;
8221 struct mm_struct *mm = NULL;
8222 unsigned int count = 0;
8223 unsigned long flags;
8226 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8227 * will stop on the parent's child_mutex that our caller is also holding
8229 if (task == TASK_TOMBSTONE)
8232 if (!ifh->nr_file_filters)
8235 mm = get_task_mm(event->ctx->task);
8239 down_read(&mm->mmap_sem);
8241 raw_spin_lock_irqsave(&ifh->lock, flags);
8242 list_for_each_entry(filter, &ifh->list, entry) {
8243 event->addr_filters_offs[count] = 0;
8246 * Adjust base offset if the filter is associated to a binary
8247 * that needs to be mapped:
8250 event->addr_filters_offs[count] =
8251 perf_addr_filter_apply(filter, mm);
8256 event->addr_filters_gen++;
8257 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8259 up_read(&mm->mmap_sem);
8264 perf_event_stop(event, 1);
8268 * Address range filtering: limiting the data to certain
8269 * instruction address ranges. Filters are ioctl()ed to us from
8270 * userspace as ascii strings.
8272 * Filter string format:
8275 * where ACTION is one of the
8276 * * "filter": limit the trace to this region
8277 * * "start": start tracing from this address
8278 * * "stop": stop tracing at this address/region;
8280 * * for kernel addresses: <start address>[/<size>]
8281 * * for object files: <start address>[/<size>]@</path/to/object/file>
8283 * if <size> is not specified, the range is treated as a single address.
8297 IF_STATE_ACTION = 0,
8302 static const match_table_t if_tokens = {
8303 { IF_ACT_FILTER, "filter" },
8304 { IF_ACT_START, "start" },
8305 { IF_ACT_STOP, "stop" },
8306 { IF_SRC_FILE, "%u/%u@%s" },
8307 { IF_SRC_KERNEL, "%u/%u" },
8308 { IF_SRC_FILEADDR, "%u@%s" },
8309 { IF_SRC_KERNELADDR, "%u" },
8310 { IF_ACT_NONE, NULL },
8314 * Address filter string parser
8317 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8318 struct list_head *filters)
8320 struct perf_addr_filter *filter = NULL;
8321 char *start, *orig, *filename = NULL;
8323 substring_t args[MAX_OPT_ARGS];
8324 int state = IF_STATE_ACTION, token;
8325 unsigned int kernel = 0;
8328 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8332 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8338 /* filter definition begins */
8339 if (state == IF_STATE_ACTION) {
8340 filter = perf_addr_filter_new(event, filters);
8345 token = match_token(start, if_tokens, args);
8352 if (state != IF_STATE_ACTION)
8355 state = IF_STATE_SOURCE;
8358 case IF_SRC_KERNELADDR:
8362 case IF_SRC_FILEADDR:
8364 if (state != IF_STATE_SOURCE)
8367 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL)
8371 ret = kstrtoul(args[0].from, 0, &filter->offset);
8375 if (filter->range) {
8377 ret = kstrtoul(args[1].from, 0, &filter->size);
8382 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8383 int fpos = filter->range ? 2 : 1;
8385 filename = match_strdup(&args[fpos]);
8392 state = IF_STATE_END;
8400 * Filter definition is fully parsed, validate and install it.
8401 * Make sure that it doesn't contradict itself or the event's
8404 if (state == IF_STATE_END) {
8406 if (kernel && event->attr.exclude_kernel)
8414 * For now, we only support file-based filters
8415 * in per-task events; doing so for CPU-wide
8416 * events requires additional context switching
8417 * trickery, since same object code will be
8418 * mapped at different virtual addresses in
8419 * different processes.
8422 if (!event->ctx->task)
8423 goto fail_free_name;
8425 /* look up the path and grab its inode */
8426 ret = kern_path(filename, LOOKUP_FOLLOW, &path);
8428 goto fail_free_name;
8430 filter->inode = igrab(d_inode(path.dentry));
8436 if (!filter->inode ||
8437 !S_ISREG(filter->inode->i_mode))
8438 /* free_filters_list() will iput() */
8441 event->addr_filters.nr_file_filters++;
8444 /* ready to consume more filters */
8445 state = IF_STATE_ACTION;
8450 if (state != IF_STATE_ACTION)
8460 free_filters_list(filters);
8467 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
8473 * Since this is called in perf_ioctl() path, we're already holding
8476 lockdep_assert_held(&event->ctx->mutex);
8478 if (WARN_ON_ONCE(event->parent))
8481 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
8483 goto fail_clear_files;
8485 ret = event->pmu->addr_filters_validate(&filters);
8487 goto fail_free_filters;
8489 /* remove existing filters, if any */
8490 perf_addr_filters_splice(event, &filters);
8492 /* install new filters */
8493 perf_event_for_each_child(event, perf_event_addr_filters_apply);
8498 free_filters_list(&filters);
8501 event->addr_filters.nr_file_filters = 0;
8506 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
8511 if ((event->attr.type != PERF_TYPE_TRACEPOINT ||
8512 !IS_ENABLED(CONFIG_EVENT_TRACING)) &&
8513 !has_addr_filter(event))
8516 filter_str = strndup_user(arg, PAGE_SIZE);
8517 if (IS_ERR(filter_str))
8518 return PTR_ERR(filter_str);
8520 if (IS_ENABLED(CONFIG_EVENT_TRACING) &&
8521 event->attr.type == PERF_TYPE_TRACEPOINT)
8522 ret = ftrace_profile_set_filter(event, event->attr.config,
8524 else if (has_addr_filter(event))
8525 ret = perf_event_set_addr_filter(event, filter_str);
8532 * hrtimer based swevent callback
8535 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
8537 enum hrtimer_restart ret = HRTIMER_RESTART;
8538 struct perf_sample_data data;
8539 struct pt_regs *regs;
8540 struct perf_event *event;
8543 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
8545 if (event->state != PERF_EVENT_STATE_ACTIVE)
8546 return HRTIMER_NORESTART;
8548 event->pmu->read(event);
8550 perf_sample_data_init(&data, 0, event->hw.last_period);
8551 regs = get_irq_regs();
8553 if (regs && !perf_exclude_event(event, regs)) {
8554 if (!(event->attr.exclude_idle && is_idle_task(current)))
8555 if (__perf_event_overflow(event, 1, &data, regs))
8556 ret = HRTIMER_NORESTART;
8559 period = max_t(u64, 10000, event->hw.sample_period);
8560 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
8565 static void perf_swevent_start_hrtimer(struct perf_event *event)
8567 struct hw_perf_event *hwc = &event->hw;
8570 if (!is_sampling_event(event))
8573 period = local64_read(&hwc->period_left);
8578 local64_set(&hwc->period_left, 0);
8580 period = max_t(u64, 10000, hwc->sample_period);
8582 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
8583 HRTIMER_MODE_REL_PINNED);
8586 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
8588 struct hw_perf_event *hwc = &event->hw;
8590 if (is_sampling_event(event)) {
8591 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
8592 local64_set(&hwc->period_left, ktime_to_ns(remaining));
8594 hrtimer_cancel(&hwc->hrtimer);
8598 static void perf_swevent_init_hrtimer(struct perf_event *event)
8600 struct hw_perf_event *hwc = &event->hw;
8602 if (!is_sampling_event(event))
8605 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
8606 hwc->hrtimer.function = perf_swevent_hrtimer;
8609 * Since hrtimers have a fixed rate, we can do a static freq->period
8610 * mapping and avoid the whole period adjust feedback stuff.
8612 if (event->attr.freq) {
8613 long freq = event->attr.sample_freq;
8615 event->attr.sample_period = NSEC_PER_SEC / freq;
8616 hwc->sample_period = event->attr.sample_period;
8617 local64_set(&hwc->period_left, hwc->sample_period);
8618 hwc->last_period = hwc->sample_period;
8619 event->attr.freq = 0;
8624 * Software event: cpu wall time clock
8627 static void cpu_clock_event_update(struct perf_event *event)
8632 now = local_clock();
8633 prev = local64_xchg(&event->hw.prev_count, now);
8634 local64_add(now - prev, &event->count);
8637 static void cpu_clock_event_start(struct perf_event *event, int flags)
8639 local64_set(&event->hw.prev_count, local_clock());
8640 perf_swevent_start_hrtimer(event);
8643 static void cpu_clock_event_stop(struct perf_event *event, int flags)
8645 perf_swevent_cancel_hrtimer(event);
8646 cpu_clock_event_update(event);
8649 static int cpu_clock_event_add(struct perf_event *event, int flags)
8651 if (flags & PERF_EF_START)
8652 cpu_clock_event_start(event, flags);
8653 perf_event_update_userpage(event);
8658 static void cpu_clock_event_del(struct perf_event *event, int flags)
8660 cpu_clock_event_stop(event, flags);
8663 static void cpu_clock_event_read(struct perf_event *event)
8665 cpu_clock_event_update(event);
8668 static int cpu_clock_event_init(struct perf_event *event)
8670 if (event->attr.type != PERF_TYPE_SOFTWARE)
8673 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
8677 * no branch sampling for software events
8679 if (has_branch_stack(event))
8682 perf_swevent_init_hrtimer(event);
8687 static struct pmu perf_cpu_clock = {
8688 .task_ctx_nr = perf_sw_context,
8690 .capabilities = PERF_PMU_CAP_NO_NMI,
8692 .event_init = cpu_clock_event_init,
8693 .add = cpu_clock_event_add,
8694 .del = cpu_clock_event_del,
8695 .start = cpu_clock_event_start,
8696 .stop = cpu_clock_event_stop,
8697 .read = cpu_clock_event_read,
8701 * Software event: task time clock
8704 static void task_clock_event_update(struct perf_event *event, u64 now)
8709 prev = local64_xchg(&event->hw.prev_count, now);
8711 local64_add(delta, &event->count);
8714 static void task_clock_event_start(struct perf_event *event, int flags)
8716 local64_set(&event->hw.prev_count, event->ctx->time);
8717 perf_swevent_start_hrtimer(event);
8720 static void task_clock_event_stop(struct perf_event *event, int flags)
8722 perf_swevent_cancel_hrtimer(event);
8723 task_clock_event_update(event, event->ctx->time);
8726 static int task_clock_event_add(struct perf_event *event, int flags)
8728 if (flags & PERF_EF_START)
8729 task_clock_event_start(event, flags);
8730 perf_event_update_userpage(event);
8735 static void task_clock_event_del(struct perf_event *event, int flags)
8737 task_clock_event_stop(event, PERF_EF_UPDATE);
8740 static void task_clock_event_read(struct perf_event *event)
8742 u64 now = perf_clock();
8743 u64 delta = now - event->ctx->timestamp;
8744 u64 time = event->ctx->time + delta;
8746 task_clock_event_update(event, time);
8749 static int task_clock_event_init(struct perf_event *event)
8751 if (event->attr.type != PERF_TYPE_SOFTWARE)
8754 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
8758 * no branch sampling for software events
8760 if (has_branch_stack(event))
8763 perf_swevent_init_hrtimer(event);
8768 static struct pmu perf_task_clock = {
8769 .task_ctx_nr = perf_sw_context,
8771 .capabilities = PERF_PMU_CAP_NO_NMI,
8773 .event_init = task_clock_event_init,
8774 .add = task_clock_event_add,
8775 .del = task_clock_event_del,
8776 .start = task_clock_event_start,
8777 .stop = task_clock_event_stop,
8778 .read = task_clock_event_read,
8781 static void perf_pmu_nop_void(struct pmu *pmu)
8785 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
8789 static int perf_pmu_nop_int(struct pmu *pmu)
8794 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
8796 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
8798 __this_cpu_write(nop_txn_flags, flags);
8800 if (flags & ~PERF_PMU_TXN_ADD)
8803 perf_pmu_disable(pmu);
8806 static int perf_pmu_commit_txn(struct pmu *pmu)
8808 unsigned int flags = __this_cpu_read(nop_txn_flags);
8810 __this_cpu_write(nop_txn_flags, 0);
8812 if (flags & ~PERF_PMU_TXN_ADD)
8815 perf_pmu_enable(pmu);
8819 static void perf_pmu_cancel_txn(struct pmu *pmu)
8821 unsigned int flags = __this_cpu_read(nop_txn_flags);
8823 __this_cpu_write(nop_txn_flags, 0);
8825 if (flags & ~PERF_PMU_TXN_ADD)
8828 perf_pmu_enable(pmu);
8831 static int perf_event_idx_default(struct perf_event *event)
8837 * Ensures all contexts with the same task_ctx_nr have the same
8838 * pmu_cpu_context too.
8840 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
8847 list_for_each_entry(pmu, &pmus, entry) {
8848 if (pmu->task_ctx_nr == ctxn)
8849 return pmu->pmu_cpu_context;
8855 static void free_pmu_context(struct pmu *pmu)
8857 mutex_lock(&pmus_lock);
8858 free_percpu(pmu->pmu_cpu_context);
8859 mutex_unlock(&pmus_lock);
8863 * Let userspace know that this PMU supports address range filtering:
8865 static ssize_t nr_addr_filters_show(struct device *dev,
8866 struct device_attribute *attr,
8869 struct pmu *pmu = dev_get_drvdata(dev);
8871 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
8873 DEVICE_ATTR_RO(nr_addr_filters);
8875 static struct idr pmu_idr;
8878 type_show(struct device *dev, struct device_attribute *attr, char *page)
8880 struct pmu *pmu = dev_get_drvdata(dev);
8882 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
8884 static DEVICE_ATTR_RO(type);
8887 perf_event_mux_interval_ms_show(struct device *dev,
8888 struct device_attribute *attr,
8891 struct pmu *pmu = dev_get_drvdata(dev);
8893 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
8896 static DEFINE_MUTEX(mux_interval_mutex);
8899 perf_event_mux_interval_ms_store(struct device *dev,
8900 struct device_attribute *attr,
8901 const char *buf, size_t count)
8903 struct pmu *pmu = dev_get_drvdata(dev);
8904 int timer, cpu, ret;
8906 ret = kstrtoint(buf, 0, &timer);
8913 /* same value, noting to do */
8914 if (timer == pmu->hrtimer_interval_ms)
8917 mutex_lock(&mux_interval_mutex);
8918 pmu->hrtimer_interval_ms = timer;
8920 /* update all cpuctx for this PMU */
8922 for_each_online_cpu(cpu) {
8923 struct perf_cpu_context *cpuctx;
8924 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
8925 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
8927 cpu_function_call(cpu,
8928 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
8931 mutex_unlock(&mux_interval_mutex);
8935 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
8937 static struct attribute *pmu_dev_attrs[] = {
8938 &dev_attr_type.attr,
8939 &dev_attr_perf_event_mux_interval_ms.attr,
8942 ATTRIBUTE_GROUPS(pmu_dev);
8944 static int pmu_bus_running;
8945 static struct bus_type pmu_bus = {
8946 .name = "event_source",
8947 .dev_groups = pmu_dev_groups,
8950 static void pmu_dev_release(struct device *dev)
8955 static int pmu_dev_alloc(struct pmu *pmu)
8959 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
8963 pmu->dev->groups = pmu->attr_groups;
8964 device_initialize(pmu->dev);
8965 ret = dev_set_name(pmu->dev, "%s", pmu->name);
8969 dev_set_drvdata(pmu->dev, pmu);
8970 pmu->dev->bus = &pmu_bus;
8971 pmu->dev->release = pmu_dev_release;
8972 ret = device_add(pmu->dev);
8976 /* For PMUs with address filters, throw in an extra attribute: */
8977 if (pmu->nr_addr_filters)
8978 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
8987 device_del(pmu->dev);
8990 put_device(pmu->dev);
8994 static struct lock_class_key cpuctx_mutex;
8995 static struct lock_class_key cpuctx_lock;
8997 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9001 mutex_lock(&pmus_lock);
9003 pmu->pmu_disable_count = alloc_percpu(int);
9004 if (!pmu->pmu_disable_count)
9013 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9021 if (pmu_bus_running) {
9022 ret = pmu_dev_alloc(pmu);
9028 if (pmu->task_ctx_nr == perf_hw_context) {
9029 static int hw_context_taken = 0;
9032 * Other than systems with heterogeneous CPUs, it never makes
9033 * sense for two PMUs to share perf_hw_context. PMUs which are
9034 * uncore must use perf_invalid_context.
9036 if (WARN_ON_ONCE(hw_context_taken &&
9037 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9038 pmu->task_ctx_nr = perf_invalid_context;
9040 hw_context_taken = 1;
9043 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9044 if (pmu->pmu_cpu_context)
9045 goto got_cpu_context;
9048 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9049 if (!pmu->pmu_cpu_context)
9052 for_each_possible_cpu(cpu) {
9053 struct perf_cpu_context *cpuctx;
9055 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9056 __perf_event_init_context(&cpuctx->ctx);
9057 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9058 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9059 cpuctx->ctx.pmu = pmu;
9060 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9062 __perf_mux_hrtimer_init(cpuctx, cpu);
9066 if (!pmu->start_txn) {
9067 if (pmu->pmu_enable) {
9069 * If we have pmu_enable/pmu_disable calls, install
9070 * transaction stubs that use that to try and batch
9071 * hardware accesses.
9073 pmu->start_txn = perf_pmu_start_txn;
9074 pmu->commit_txn = perf_pmu_commit_txn;
9075 pmu->cancel_txn = perf_pmu_cancel_txn;
9077 pmu->start_txn = perf_pmu_nop_txn;
9078 pmu->commit_txn = perf_pmu_nop_int;
9079 pmu->cancel_txn = perf_pmu_nop_void;
9083 if (!pmu->pmu_enable) {
9084 pmu->pmu_enable = perf_pmu_nop_void;
9085 pmu->pmu_disable = perf_pmu_nop_void;
9088 if (!pmu->event_idx)
9089 pmu->event_idx = perf_event_idx_default;
9091 list_add_rcu(&pmu->entry, &pmus);
9092 atomic_set(&pmu->exclusive_cnt, 0);
9095 mutex_unlock(&pmus_lock);
9100 device_del(pmu->dev);
9101 put_device(pmu->dev);
9104 if (pmu->type >= PERF_TYPE_MAX)
9105 idr_remove(&pmu_idr, pmu->type);
9108 free_percpu(pmu->pmu_disable_count);
9111 EXPORT_SYMBOL_GPL(perf_pmu_register);
9113 void perf_pmu_unregister(struct pmu *pmu)
9117 mutex_lock(&pmus_lock);
9118 remove_device = pmu_bus_running;
9119 list_del_rcu(&pmu->entry);
9120 mutex_unlock(&pmus_lock);
9123 * We dereference the pmu list under both SRCU and regular RCU, so
9124 * synchronize against both of those.
9126 synchronize_srcu(&pmus_srcu);
9129 free_percpu(pmu->pmu_disable_count);
9130 if (pmu->type >= PERF_TYPE_MAX)
9131 idr_remove(&pmu_idr, pmu->type);
9132 if (remove_device) {
9133 if (pmu->nr_addr_filters)
9134 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9135 device_del(pmu->dev);
9136 put_device(pmu->dev);
9138 free_pmu_context(pmu);
9140 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9142 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9144 struct perf_event_context *ctx = NULL;
9147 if (!try_module_get(pmu->module))
9150 if (event->group_leader != event) {
9152 * This ctx->mutex can nest when we're called through
9153 * inheritance. See the perf_event_ctx_lock_nested() comment.
9155 ctx = perf_event_ctx_lock_nested(event->group_leader,
9156 SINGLE_DEPTH_NESTING);
9161 ret = pmu->event_init(event);
9164 perf_event_ctx_unlock(event->group_leader, ctx);
9167 module_put(pmu->module);
9172 static struct pmu *perf_init_event(struct perf_event *event)
9178 idx = srcu_read_lock(&pmus_srcu);
9180 /* Try parent's PMU first: */
9181 if (event->parent && event->parent->pmu) {
9182 pmu = event->parent->pmu;
9183 ret = perf_try_init_event(pmu, event);
9189 pmu = idr_find(&pmu_idr, event->attr.type);
9192 ret = perf_try_init_event(pmu, event);
9198 list_for_each_entry_rcu(pmu, &pmus, entry) {
9199 ret = perf_try_init_event(pmu, event);
9203 if (ret != -ENOENT) {
9208 pmu = ERR_PTR(-ENOENT);
9210 srcu_read_unlock(&pmus_srcu, idx);
9215 static void attach_sb_event(struct perf_event *event)
9217 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9219 raw_spin_lock(&pel->lock);
9220 list_add_rcu(&event->sb_list, &pel->list);
9221 raw_spin_unlock(&pel->lock);
9225 * We keep a list of all !task (and therefore per-cpu) events
9226 * that need to receive side-band records.
9228 * This avoids having to scan all the various PMU per-cpu contexts
9231 static void account_pmu_sb_event(struct perf_event *event)
9233 if (is_sb_event(event))
9234 attach_sb_event(event);
9237 static void account_event_cpu(struct perf_event *event, int cpu)
9242 if (is_cgroup_event(event))
9243 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9246 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9247 static void account_freq_event_nohz(void)
9249 #ifdef CONFIG_NO_HZ_FULL
9250 /* Lock so we don't race with concurrent unaccount */
9251 spin_lock(&nr_freq_lock);
9252 if (atomic_inc_return(&nr_freq_events) == 1)
9253 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9254 spin_unlock(&nr_freq_lock);
9258 static void account_freq_event(void)
9260 if (tick_nohz_full_enabled())
9261 account_freq_event_nohz();
9263 atomic_inc(&nr_freq_events);
9267 static void account_event(struct perf_event *event)
9274 if (event->attach_state & PERF_ATTACH_TASK)
9276 if (event->attr.mmap || event->attr.mmap_data)
9277 atomic_inc(&nr_mmap_events);
9278 if (event->attr.comm)
9279 atomic_inc(&nr_comm_events);
9280 if (event->attr.namespaces)
9281 atomic_inc(&nr_namespaces_events);
9282 if (event->attr.task)
9283 atomic_inc(&nr_task_events);
9284 if (event->attr.freq)
9285 account_freq_event();
9286 if (event->attr.context_switch) {
9287 atomic_inc(&nr_switch_events);
9290 if (has_branch_stack(event))
9292 if (is_cgroup_event(event))
9296 if (atomic_inc_not_zero(&perf_sched_count))
9299 mutex_lock(&perf_sched_mutex);
9300 if (!atomic_read(&perf_sched_count)) {
9301 static_branch_enable(&perf_sched_events);
9303 * Guarantee that all CPUs observe they key change and
9304 * call the perf scheduling hooks before proceeding to
9305 * install events that need them.
9307 synchronize_sched();
9310 * Now that we have waited for the sync_sched(), allow further
9311 * increments to by-pass the mutex.
9313 atomic_inc(&perf_sched_count);
9314 mutex_unlock(&perf_sched_mutex);
9318 account_event_cpu(event, event->cpu);
9320 account_pmu_sb_event(event);
9324 * Allocate and initialize a event structure
9326 static struct perf_event *
9327 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9328 struct task_struct *task,
9329 struct perf_event *group_leader,
9330 struct perf_event *parent_event,
9331 perf_overflow_handler_t overflow_handler,
9332 void *context, int cgroup_fd)
9335 struct perf_event *event;
9336 struct hw_perf_event *hwc;
9339 if ((unsigned)cpu >= nr_cpu_ids) {
9340 if (!task || cpu != -1)
9341 return ERR_PTR(-EINVAL);
9344 event = kzalloc(sizeof(*event), GFP_KERNEL);
9346 return ERR_PTR(-ENOMEM);
9349 * Single events are their own group leaders, with an
9350 * empty sibling list:
9353 group_leader = event;
9355 mutex_init(&event->child_mutex);
9356 INIT_LIST_HEAD(&event->child_list);
9358 INIT_LIST_HEAD(&event->group_entry);
9359 INIT_LIST_HEAD(&event->event_entry);
9360 INIT_LIST_HEAD(&event->sibling_list);
9361 INIT_LIST_HEAD(&event->rb_entry);
9362 INIT_LIST_HEAD(&event->active_entry);
9363 INIT_LIST_HEAD(&event->addr_filters.list);
9364 INIT_HLIST_NODE(&event->hlist_entry);
9367 init_waitqueue_head(&event->waitq);
9368 init_irq_work(&event->pending, perf_pending_event);
9370 mutex_init(&event->mmap_mutex);
9371 raw_spin_lock_init(&event->addr_filters.lock);
9373 atomic_long_set(&event->refcount, 1);
9375 event->attr = *attr;
9376 event->group_leader = group_leader;
9380 event->parent = parent_event;
9382 event->ns = get_pid_ns(task_active_pid_ns(current));
9383 event->id = atomic64_inc_return(&perf_event_id);
9385 event->state = PERF_EVENT_STATE_INACTIVE;
9388 event->attach_state = PERF_ATTACH_TASK;
9390 * XXX pmu::event_init needs to know what task to account to
9391 * and we cannot use the ctx information because we need the
9392 * pmu before we get a ctx.
9394 event->hw.target = task;
9397 event->clock = &local_clock;
9399 event->clock = parent_event->clock;
9401 if (!overflow_handler && parent_event) {
9402 overflow_handler = parent_event->overflow_handler;
9403 context = parent_event->overflow_handler_context;
9404 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
9405 if (overflow_handler == bpf_overflow_handler) {
9406 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
9409 err = PTR_ERR(prog);
9413 event->orig_overflow_handler =
9414 parent_event->orig_overflow_handler;
9419 if (overflow_handler) {
9420 event->overflow_handler = overflow_handler;
9421 event->overflow_handler_context = context;
9422 } else if (is_write_backward(event)){
9423 event->overflow_handler = perf_event_output_backward;
9424 event->overflow_handler_context = NULL;
9426 event->overflow_handler = perf_event_output_forward;
9427 event->overflow_handler_context = NULL;
9430 perf_event__state_init(event);
9435 hwc->sample_period = attr->sample_period;
9436 if (attr->freq && attr->sample_freq)
9437 hwc->sample_period = 1;
9438 hwc->last_period = hwc->sample_period;
9440 local64_set(&hwc->period_left, hwc->sample_period);
9443 * We currently do not support PERF_SAMPLE_READ on inherited events.
9444 * See perf_output_read().
9446 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
9449 if (!has_branch_stack(event))
9450 event->attr.branch_sample_type = 0;
9452 if (cgroup_fd != -1) {
9453 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
9458 pmu = perf_init_event(event);
9464 err = exclusive_event_init(event);
9468 if (has_addr_filter(event)) {
9469 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
9470 sizeof(unsigned long),
9472 if (!event->addr_filters_offs) {
9477 /* force hw sync on the address filters */
9478 event->addr_filters_gen = 1;
9481 if (!event->parent) {
9482 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
9483 err = get_callchain_buffers(attr->sample_max_stack);
9485 goto err_addr_filters;
9489 /* symmetric to unaccount_event() in _free_event() */
9490 account_event(event);
9495 kfree(event->addr_filters_offs);
9498 exclusive_event_destroy(event);
9502 event->destroy(event);
9503 module_put(pmu->module);
9505 if (is_cgroup_event(event))
9506 perf_detach_cgroup(event);
9508 put_pid_ns(event->ns);
9511 return ERR_PTR(err);
9514 static int perf_copy_attr(struct perf_event_attr __user *uattr,
9515 struct perf_event_attr *attr)
9520 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
9524 * zero the full structure, so that a short copy will be nice.
9526 memset(attr, 0, sizeof(*attr));
9528 ret = get_user(size, &uattr->size);
9532 if (size > PAGE_SIZE) /* silly large */
9535 if (!size) /* abi compat */
9536 size = PERF_ATTR_SIZE_VER0;
9538 if (size < PERF_ATTR_SIZE_VER0)
9542 * If we're handed a bigger struct than we know of,
9543 * ensure all the unknown bits are 0 - i.e. new
9544 * user-space does not rely on any kernel feature
9545 * extensions we dont know about yet.
9547 if (size > sizeof(*attr)) {
9548 unsigned char __user *addr;
9549 unsigned char __user *end;
9552 addr = (void __user *)uattr + sizeof(*attr);
9553 end = (void __user *)uattr + size;
9555 for (; addr < end; addr++) {
9556 ret = get_user(val, addr);
9562 size = sizeof(*attr);
9565 ret = copy_from_user(attr, uattr, size);
9569 if (attr->__reserved_1)
9572 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
9575 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
9578 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
9579 u64 mask = attr->branch_sample_type;
9581 /* only using defined bits */
9582 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
9585 /* at least one branch bit must be set */
9586 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
9589 /* propagate priv level, when not set for branch */
9590 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
9592 /* exclude_kernel checked on syscall entry */
9593 if (!attr->exclude_kernel)
9594 mask |= PERF_SAMPLE_BRANCH_KERNEL;
9596 if (!attr->exclude_user)
9597 mask |= PERF_SAMPLE_BRANCH_USER;
9599 if (!attr->exclude_hv)
9600 mask |= PERF_SAMPLE_BRANCH_HV;
9602 * adjust user setting (for HW filter setup)
9604 attr->branch_sample_type = mask;
9606 /* privileged levels capture (kernel, hv): check permissions */
9607 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
9608 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9612 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
9613 ret = perf_reg_validate(attr->sample_regs_user);
9618 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
9619 if (!arch_perf_have_user_stack_dump())
9623 * We have __u32 type for the size, but so far
9624 * we can only use __u16 as maximum due to the
9625 * __u16 sample size limit.
9627 if (attr->sample_stack_user >= USHRT_MAX)
9629 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
9633 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
9634 ret = perf_reg_validate(attr->sample_regs_intr);
9639 put_user(sizeof(*attr), &uattr->size);
9645 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
9647 struct ring_buffer *rb = NULL;
9653 /* don't allow circular references */
9654 if (event == output_event)
9658 * Don't allow cross-cpu buffers
9660 if (output_event->cpu != event->cpu)
9664 * If its not a per-cpu rb, it must be the same task.
9666 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
9670 * Mixing clocks in the same buffer is trouble you don't need.
9672 if (output_event->clock != event->clock)
9676 * Either writing ring buffer from beginning or from end.
9677 * Mixing is not allowed.
9679 if (is_write_backward(output_event) != is_write_backward(event))
9683 * If both events generate aux data, they must be on the same PMU
9685 if (has_aux(event) && has_aux(output_event) &&
9686 event->pmu != output_event->pmu)
9690 mutex_lock(&event->mmap_mutex);
9691 /* Can't redirect output if we've got an active mmap() */
9692 if (atomic_read(&event->mmap_count))
9696 /* get the rb we want to redirect to */
9697 rb = ring_buffer_get(output_event);
9702 ring_buffer_attach(event, rb);
9706 mutex_unlock(&event->mmap_mutex);
9712 static void mutex_lock_double(struct mutex *a, struct mutex *b)
9718 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
9721 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
9723 bool nmi_safe = false;
9726 case CLOCK_MONOTONIC:
9727 event->clock = &ktime_get_mono_fast_ns;
9731 case CLOCK_MONOTONIC_RAW:
9732 event->clock = &ktime_get_raw_fast_ns;
9736 case CLOCK_REALTIME:
9737 event->clock = &ktime_get_real_ns;
9740 case CLOCK_BOOTTIME:
9741 event->clock = &ktime_get_boot_ns;
9745 event->clock = &ktime_get_tai_ns;
9752 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
9759 * Variation on perf_event_ctx_lock_nested(), except we take two context
9762 static struct perf_event_context *
9763 __perf_event_ctx_lock_double(struct perf_event *group_leader,
9764 struct perf_event_context *ctx)
9766 struct perf_event_context *gctx;
9770 gctx = READ_ONCE(group_leader->ctx);
9771 if (!atomic_inc_not_zero(&gctx->refcount)) {
9777 mutex_lock_double(&gctx->mutex, &ctx->mutex);
9779 if (group_leader->ctx != gctx) {
9780 mutex_unlock(&ctx->mutex);
9781 mutex_unlock(&gctx->mutex);
9790 * sys_perf_event_open - open a performance event, associate it to a task/cpu
9792 * @attr_uptr: event_id type attributes for monitoring/sampling
9795 * @group_fd: group leader event fd
9797 SYSCALL_DEFINE5(perf_event_open,
9798 struct perf_event_attr __user *, attr_uptr,
9799 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
9801 struct perf_event *group_leader = NULL, *output_event = NULL;
9802 struct perf_event *event, *sibling;
9803 struct perf_event_attr attr;
9804 struct perf_event_context *ctx, *uninitialized_var(gctx);
9805 struct file *event_file = NULL;
9806 struct fd group = {NULL, 0};
9807 struct task_struct *task = NULL;
9812 int f_flags = O_RDWR;
9815 /* for future expandability... */
9816 if (flags & ~PERF_FLAG_ALL)
9819 err = perf_copy_attr(attr_uptr, &attr);
9823 if (!attr.exclude_kernel) {
9824 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
9828 if (attr.namespaces) {
9829 if (!capable(CAP_SYS_ADMIN))
9834 if (attr.sample_freq > sysctl_perf_event_sample_rate)
9837 if (attr.sample_period & (1ULL << 63))
9841 if (!attr.sample_max_stack)
9842 attr.sample_max_stack = sysctl_perf_event_max_stack;
9845 * In cgroup mode, the pid argument is used to pass the fd
9846 * opened to the cgroup directory in cgroupfs. The cpu argument
9847 * designates the cpu on which to monitor threads from that
9850 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
9853 if (flags & PERF_FLAG_FD_CLOEXEC)
9854 f_flags |= O_CLOEXEC;
9856 event_fd = get_unused_fd_flags(f_flags);
9860 if (group_fd != -1) {
9861 err = perf_fget_light(group_fd, &group);
9864 group_leader = group.file->private_data;
9865 if (flags & PERF_FLAG_FD_OUTPUT)
9866 output_event = group_leader;
9867 if (flags & PERF_FLAG_FD_NO_GROUP)
9868 group_leader = NULL;
9871 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
9872 task = find_lively_task_by_vpid(pid);
9874 err = PTR_ERR(task);
9879 if (task && group_leader &&
9880 group_leader->attr.inherit != attr.inherit) {
9886 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
9891 * Reuse ptrace permission checks for now.
9893 * We must hold cred_guard_mutex across this and any potential
9894 * perf_install_in_context() call for this new event to
9895 * serialize against exec() altering our credentials (and the
9896 * perf_event_exit_task() that could imply).
9899 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
9903 if (flags & PERF_FLAG_PID_CGROUP)
9906 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
9907 NULL, NULL, cgroup_fd);
9908 if (IS_ERR(event)) {
9909 err = PTR_ERR(event);
9913 if (is_sampling_event(event)) {
9914 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
9921 * Special case software events and allow them to be part of
9922 * any hardware group.
9926 if (attr.use_clockid) {
9927 err = perf_event_set_clock(event, attr.clockid);
9932 if (pmu->task_ctx_nr == perf_sw_context)
9933 event->event_caps |= PERF_EV_CAP_SOFTWARE;
9936 (is_software_event(event) != is_software_event(group_leader))) {
9937 if (is_software_event(event)) {
9939 * If event and group_leader are not both a software
9940 * event, and event is, then group leader is not.
9942 * Allow the addition of software events to !software
9943 * groups, this is safe because software events never
9946 pmu = group_leader->pmu;
9947 } else if (is_software_event(group_leader) &&
9948 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
9950 * In case the group is a pure software group, and we
9951 * try to add a hardware event, move the whole group to
9952 * the hardware context.
9959 * Get the target context (task or percpu):
9961 ctx = find_get_context(pmu, task, event);
9967 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
9973 * Look up the group leader (we will attach this event to it):
9979 * Do not allow a recursive hierarchy (this new sibling
9980 * becoming part of another group-sibling):
9982 if (group_leader->group_leader != group_leader)
9985 /* All events in a group should have the same clock */
9986 if (group_leader->clock != event->clock)
9990 * Do not allow to attach to a group in a different
9991 * task or CPU context:
9995 * Make sure we're both on the same task, or both
9998 if (group_leader->ctx->task != ctx->task)
10002 * Make sure we're both events for the same CPU;
10003 * grouping events for different CPUs is broken; since
10004 * you can never concurrently schedule them anyhow.
10006 if (group_leader->cpu != event->cpu)
10009 if (group_leader->ctx != ctx)
10014 * Only a group leader can be exclusive or pinned
10016 if (attr.exclusive || attr.pinned)
10020 if (output_event) {
10021 err = perf_event_set_output(event, output_event);
10026 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10028 if (IS_ERR(event_file)) {
10029 err = PTR_ERR(event_file);
10035 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10037 if (gctx->task == TASK_TOMBSTONE) {
10043 * Check if we raced against another sys_perf_event_open() call
10044 * moving the software group underneath us.
10046 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10048 * If someone moved the group out from under us, check
10049 * if this new event wound up on the same ctx, if so
10050 * its the regular !move_group case, otherwise fail.
10056 perf_event_ctx_unlock(group_leader, gctx);
10061 mutex_lock(&ctx->mutex);
10064 if (ctx->task == TASK_TOMBSTONE) {
10069 if (!perf_event_validate_size(event)) {
10076 * Check if the @cpu we're creating an event for is online.
10078 * We use the perf_cpu_context::ctx::mutex to serialize against
10079 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10081 struct perf_cpu_context *cpuctx =
10082 container_of(ctx, struct perf_cpu_context, ctx);
10084 if (!cpuctx->online) {
10092 * Must be under the same ctx::mutex as perf_install_in_context(),
10093 * because we need to serialize with concurrent event creation.
10095 if (!exclusive_event_installable(event, ctx)) {
10096 /* exclusive and group stuff are assumed mutually exclusive */
10097 WARN_ON_ONCE(move_group);
10103 WARN_ON_ONCE(ctx->parent_ctx);
10106 * This is the point on no return; we cannot fail hereafter. This is
10107 * where we start modifying current state.
10112 * See perf_event_ctx_lock() for comments on the details
10113 * of swizzling perf_event::ctx.
10115 perf_remove_from_context(group_leader, 0);
10118 list_for_each_entry(sibling, &group_leader->sibling_list,
10120 perf_remove_from_context(sibling, 0);
10125 * Wait for everybody to stop referencing the events through
10126 * the old lists, before installing it on new lists.
10131 * Install the group siblings before the group leader.
10133 * Because a group leader will try and install the entire group
10134 * (through the sibling list, which is still in-tact), we can
10135 * end up with siblings installed in the wrong context.
10137 * By installing siblings first we NO-OP because they're not
10138 * reachable through the group lists.
10140 list_for_each_entry(sibling, &group_leader->sibling_list,
10142 perf_event__state_init(sibling);
10143 perf_install_in_context(ctx, sibling, sibling->cpu);
10148 * Removing from the context ends up with disabled
10149 * event. What we want here is event in the initial
10150 * startup state, ready to be add into new context.
10152 perf_event__state_init(group_leader);
10153 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10158 * Precalculate sample_data sizes; do while holding ctx::mutex such
10159 * that we're serialized against further additions and before
10160 * perf_install_in_context() which is the point the event is active and
10161 * can use these values.
10163 perf_event__header_size(event);
10164 perf_event__id_header_size(event);
10166 event->owner = current;
10168 perf_install_in_context(ctx, event, event->cpu);
10169 perf_unpin_context(ctx);
10172 perf_event_ctx_unlock(group_leader, gctx);
10173 mutex_unlock(&ctx->mutex);
10176 mutex_unlock(&task->signal->cred_guard_mutex);
10177 put_task_struct(task);
10180 mutex_lock(¤t->perf_event_mutex);
10181 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10182 mutex_unlock(¤t->perf_event_mutex);
10185 * Drop the reference on the group_event after placing the
10186 * new event on the sibling_list. This ensures destruction
10187 * of the group leader will find the pointer to itself in
10188 * perf_group_detach().
10191 fd_install(event_fd, event_file);
10196 perf_event_ctx_unlock(group_leader, gctx);
10197 mutex_unlock(&ctx->mutex);
10201 perf_unpin_context(ctx);
10205 * If event_file is set, the fput() above will have called ->release()
10206 * and that will take care of freeing the event.
10212 mutex_unlock(&task->signal->cred_guard_mutex);
10215 put_task_struct(task);
10219 put_unused_fd(event_fd);
10224 * perf_event_create_kernel_counter
10226 * @attr: attributes of the counter to create
10227 * @cpu: cpu in which the counter is bound
10228 * @task: task to profile (NULL for percpu)
10230 struct perf_event *
10231 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10232 struct task_struct *task,
10233 perf_overflow_handler_t overflow_handler,
10236 struct perf_event_context *ctx;
10237 struct perf_event *event;
10241 * Get the target context (task or percpu):
10244 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10245 overflow_handler, context, -1);
10246 if (IS_ERR(event)) {
10247 err = PTR_ERR(event);
10251 /* Mark owner so we could distinguish it from user events. */
10252 event->owner = TASK_TOMBSTONE;
10254 ctx = find_get_context(event->pmu, task, event);
10256 err = PTR_ERR(ctx);
10260 WARN_ON_ONCE(ctx->parent_ctx);
10261 mutex_lock(&ctx->mutex);
10262 if (ctx->task == TASK_TOMBSTONE) {
10269 * Check if the @cpu we're creating an event for is online.
10271 * We use the perf_cpu_context::ctx::mutex to serialize against
10272 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10274 struct perf_cpu_context *cpuctx =
10275 container_of(ctx, struct perf_cpu_context, ctx);
10276 if (!cpuctx->online) {
10282 if (!exclusive_event_installable(event, ctx)) {
10287 perf_install_in_context(ctx, event, cpu);
10288 perf_unpin_context(ctx);
10289 mutex_unlock(&ctx->mutex);
10294 mutex_unlock(&ctx->mutex);
10295 perf_unpin_context(ctx);
10300 return ERR_PTR(err);
10302 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10304 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10306 struct perf_event_context *src_ctx;
10307 struct perf_event_context *dst_ctx;
10308 struct perf_event *event, *tmp;
10311 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10312 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10315 * See perf_event_ctx_lock() for comments on the details
10316 * of swizzling perf_event::ctx.
10318 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10319 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10321 perf_remove_from_context(event, 0);
10322 unaccount_event_cpu(event, src_cpu);
10324 list_add(&event->migrate_entry, &events);
10328 * Wait for the events to quiesce before re-instating them.
10333 * Re-instate events in 2 passes.
10335 * Skip over group leaders and only install siblings on this first
10336 * pass, siblings will not get enabled without a leader, however a
10337 * leader will enable its siblings, even if those are still on the old
10340 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10341 if (event->group_leader == event)
10344 list_del(&event->migrate_entry);
10345 if (event->state >= PERF_EVENT_STATE_OFF)
10346 event->state = PERF_EVENT_STATE_INACTIVE;
10347 account_event_cpu(event, dst_cpu);
10348 perf_install_in_context(dst_ctx, event, dst_cpu);
10353 * Once all the siblings are setup properly, install the group leaders
10356 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10357 list_del(&event->migrate_entry);
10358 if (event->state >= PERF_EVENT_STATE_OFF)
10359 event->state = PERF_EVENT_STATE_INACTIVE;
10360 account_event_cpu(event, dst_cpu);
10361 perf_install_in_context(dst_ctx, event, dst_cpu);
10364 mutex_unlock(&dst_ctx->mutex);
10365 mutex_unlock(&src_ctx->mutex);
10367 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
10369 static void sync_child_event(struct perf_event *child_event,
10370 struct task_struct *child)
10372 struct perf_event *parent_event = child_event->parent;
10375 if (child_event->attr.inherit_stat)
10376 perf_event_read_event(child_event, child);
10378 child_val = perf_event_count(child_event);
10381 * Add back the child's count to the parent's count:
10383 atomic64_add(child_val, &parent_event->child_count);
10384 atomic64_add(child_event->total_time_enabled,
10385 &parent_event->child_total_time_enabled);
10386 atomic64_add(child_event->total_time_running,
10387 &parent_event->child_total_time_running);
10391 perf_event_exit_event(struct perf_event *child_event,
10392 struct perf_event_context *child_ctx,
10393 struct task_struct *child)
10395 struct perf_event *parent_event = child_event->parent;
10398 * Do not destroy the 'original' grouping; because of the context
10399 * switch optimization the original events could've ended up in a
10400 * random child task.
10402 * If we were to destroy the original group, all group related
10403 * operations would cease to function properly after this random
10406 * Do destroy all inherited groups, we don't care about those
10407 * and being thorough is better.
10409 raw_spin_lock_irq(&child_ctx->lock);
10410 WARN_ON_ONCE(child_ctx->is_active);
10413 perf_group_detach(child_event);
10414 list_del_event(child_event, child_ctx);
10415 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */
10416 raw_spin_unlock_irq(&child_ctx->lock);
10419 * Parent events are governed by their filedesc, retain them.
10421 if (!parent_event) {
10422 perf_event_wakeup(child_event);
10426 * Child events can be cleaned up.
10429 sync_child_event(child_event, child);
10432 * Remove this event from the parent's list
10434 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
10435 mutex_lock(&parent_event->child_mutex);
10436 list_del_init(&child_event->child_list);
10437 mutex_unlock(&parent_event->child_mutex);
10440 * Kick perf_poll() for is_event_hup().
10442 perf_event_wakeup(parent_event);
10443 free_event(child_event);
10444 put_event(parent_event);
10447 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
10449 struct perf_event_context *child_ctx, *clone_ctx = NULL;
10450 struct perf_event *child_event, *next;
10452 WARN_ON_ONCE(child != current);
10454 child_ctx = perf_pin_task_context(child, ctxn);
10459 * In order to reduce the amount of tricky in ctx tear-down, we hold
10460 * ctx::mutex over the entire thing. This serializes against almost
10461 * everything that wants to access the ctx.
10463 * The exception is sys_perf_event_open() /
10464 * perf_event_create_kernel_count() which does find_get_context()
10465 * without ctx::mutex (it cannot because of the move_group double mutex
10466 * lock thing). See the comments in perf_install_in_context().
10468 mutex_lock(&child_ctx->mutex);
10471 * In a single ctx::lock section, de-schedule the events and detach the
10472 * context from the task such that we cannot ever get it scheduled back
10475 raw_spin_lock_irq(&child_ctx->lock);
10476 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
10479 * Now that the context is inactive, destroy the task <-> ctx relation
10480 * and mark the context dead.
10482 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
10483 put_ctx(child_ctx); /* cannot be last */
10484 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
10485 put_task_struct(current); /* cannot be last */
10487 clone_ctx = unclone_ctx(child_ctx);
10488 raw_spin_unlock_irq(&child_ctx->lock);
10491 put_ctx(clone_ctx);
10494 * Report the task dead after unscheduling the events so that we
10495 * won't get any samples after PERF_RECORD_EXIT. We can however still
10496 * get a few PERF_RECORD_READ events.
10498 perf_event_task(child, child_ctx, 0);
10500 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
10501 perf_event_exit_event(child_event, child_ctx, child);
10503 mutex_unlock(&child_ctx->mutex);
10505 put_ctx(child_ctx);
10509 * When a child task exits, feed back event values to parent events.
10511 * Can be called with cred_guard_mutex held when called from
10512 * install_exec_creds().
10514 void perf_event_exit_task(struct task_struct *child)
10516 struct perf_event *event, *tmp;
10519 mutex_lock(&child->perf_event_mutex);
10520 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
10522 list_del_init(&event->owner_entry);
10525 * Ensure the list deletion is visible before we clear
10526 * the owner, closes a race against perf_release() where
10527 * we need to serialize on the owner->perf_event_mutex.
10529 smp_store_release(&event->owner, NULL);
10531 mutex_unlock(&child->perf_event_mutex);
10533 for_each_task_context_nr(ctxn)
10534 perf_event_exit_task_context(child, ctxn);
10537 * The perf_event_exit_task_context calls perf_event_task
10538 * with child's task_ctx, which generates EXIT events for
10539 * child contexts and sets child->perf_event_ctxp[] to NULL.
10540 * At this point we need to send EXIT events to cpu contexts.
10542 perf_event_task(child, NULL, 0);
10545 static void perf_free_event(struct perf_event *event,
10546 struct perf_event_context *ctx)
10548 struct perf_event *parent = event->parent;
10550 if (WARN_ON_ONCE(!parent))
10553 mutex_lock(&parent->child_mutex);
10554 list_del_init(&event->child_list);
10555 mutex_unlock(&parent->child_mutex);
10559 raw_spin_lock_irq(&ctx->lock);
10560 perf_group_detach(event);
10561 list_del_event(event, ctx);
10562 raw_spin_unlock_irq(&ctx->lock);
10567 * Free an unexposed, unused context as created by inheritance by
10568 * perf_event_init_task below, used by fork() in case of fail.
10570 * Not all locks are strictly required, but take them anyway to be nice and
10571 * help out with the lockdep assertions.
10573 void perf_event_free_task(struct task_struct *task)
10575 struct perf_event_context *ctx;
10576 struct perf_event *event, *tmp;
10579 for_each_task_context_nr(ctxn) {
10580 ctx = task->perf_event_ctxp[ctxn];
10584 mutex_lock(&ctx->mutex);
10585 raw_spin_lock_irq(&ctx->lock);
10587 * Destroy the task <-> ctx relation and mark the context dead.
10589 * This is important because even though the task hasn't been
10590 * exposed yet the context has been (through child_list).
10592 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
10593 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
10594 put_task_struct(task); /* cannot be last */
10595 raw_spin_unlock_irq(&ctx->lock);
10597 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
10598 perf_free_event(event, ctx);
10600 mutex_unlock(&ctx->mutex);
10605 void perf_event_delayed_put(struct task_struct *task)
10609 for_each_task_context_nr(ctxn)
10610 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
10613 struct file *perf_event_get(unsigned int fd)
10617 file = fget_raw(fd);
10619 return ERR_PTR(-EBADF);
10621 if (file->f_op != &perf_fops) {
10623 return ERR_PTR(-EBADF);
10629 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
10632 return ERR_PTR(-EINVAL);
10634 return &event->attr;
10638 * Inherit a event from parent task to child task.
10641 * - valid pointer on success
10642 * - NULL for orphaned events
10643 * - IS_ERR() on error
10645 static struct perf_event *
10646 inherit_event(struct perf_event *parent_event,
10647 struct task_struct *parent,
10648 struct perf_event_context *parent_ctx,
10649 struct task_struct *child,
10650 struct perf_event *group_leader,
10651 struct perf_event_context *child_ctx)
10653 enum perf_event_active_state parent_state = parent_event->state;
10654 struct perf_event *child_event;
10655 unsigned long flags;
10658 * Instead of creating recursive hierarchies of events,
10659 * we link inherited events back to the original parent,
10660 * which has a filp for sure, which we use as the reference
10663 if (parent_event->parent)
10664 parent_event = parent_event->parent;
10666 child_event = perf_event_alloc(&parent_event->attr,
10669 group_leader, parent_event,
10671 if (IS_ERR(child_event))
10672 return child_event;
10675 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
10676 * must be under the same lock in order to serialize against
10677 * perf_event_release_kernel(), such that either we must observe
10678 * is_orphaned_event() or they will observe us on the child_list.
10680 mutex_lock(&parent_event->child_mutex);
10681 if (is_orphaned_event(parent_event) ||
10682 !atomic_long_inc_not_zero(&parent_event->refcount)) {
10683 mutex_unlock(&parent_event->child_mutex);
10684 free_event(child_event);
10688 get_ctx(child_ctx);
10691 * Make the child state follow the state of the parent event,
10692 * not its attr.disabled bit. We hold the parent's mutex,
10693 * so we won't race with perf_event_{en, dis}able_family.
10695 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
10696 child_event->state = PERF_EVENT_STATE_INACTIVE;
10698 child_event->state = PERF_EVENT_STATE_OFF;
10700 if (parent_event->attr.freq) {
10701 u64 sample_period = parent_event->hw.sample_period;
10702 struct hw_perf_event *hwc = &child_event->hw;
10704 hwc->sample_period = sample_period;
10705 hwc->last_period = sample_period;
10707 local64_set(&hwc->period_left, sample_period);
10710 child_event->ctx = child_ctx;
10711 child_event->overflow_handler = parent_event->overflow_handler;
10712 child_event->overflow_handler_context
10713 = parent_event->overflow_handler_context;
10716 * Precalculate sample_data sizes
10718 perf_event__header_size(child_event);
10719 perf_event__id_header_size(child_event);
10722 * Link it up in the child's context:
10724 raw_spin_lock_irqsave(&child_ctx->lock, flags);
10725 add_event_to_ctx(child_event, child_ctx);
10726 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
10729 * Link this into the parent event's child list
10731 list_add_tail(&child_event->child_list, &parent_event->child_list);
10732 mutex_unlock(&parent_event->child_mutex);
10734 return child_event;
10738 * Inherits an event group.
10740 * This will quietly suppress orphaned events; !inherit_event() is not an error.
10741 * This matches with perf_event_release_kernel() removing all child events.
10747 static int inherit_group(struct perf_event *parent_event,
10748 struct task_struct *parent,
10749 struct perf_event_context *parent_ctx,
10750 struct task_struct *child,
10751 struct perf_event_context *child_ctx)
10753 struct perf_event *leader;
10754 struct perf_event *sub;
10755 struct perf_event *child_ctr;
10757 leader = inherit_event(parent_event, parent, parent_ctx,
10758 child, NULL, child_ctx);
10759 if (IS_ERR(leader))
10760 return PTR_ERR(leader);
10762 * @leader can be NULL here because of is_orphaned_event(). In this
10763 * case inherit_event() will create individual events, similar to what
10764 * perf_group_detach() would do anyway.
10766 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
10767 child_ctr = inherit_event(sub, parent, parent_ctx,
10768 child, leader, child_ctx);
10769 if (IS_ERR(child_ctr))
10770 return PTR_ERR(child_ctr);
10776 * Creates the child task context and tries to inherit the event-group.
10778 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
10779 * inherited_all set when we 'fail' to inherit an orphaned event; this is
10780 * consistent with perf_event_release_kernel() removing all child events.
10787 inherit_task_group(struct perf_event *event, struct task_struct *parent,
10788 struct perf_event_context *parent_ctx,
10789 struct task_struct *child, int ctxn,
10790 int *inherited_all)
10793 struct perf_event_context *child_ctx;
10795 if (!event->attr.inherit) {
10796 *inherited_all = 0;
10800 child_ctx = child->perf_event_ctxp[ctxn];
10803 * This is executed from the parent task context, so
10804 * inherit events that have been marked for cloning.
10805 * First allocate and initialize a context for the
10808 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
10812 child->perf_event_ctxp[ctxn] = child_ctx;
10815 ret = inherit_group(event, parent, parent_ctx,
10819 *inherited_all = 0;
10825 * Initialize the perf_event context in task_struct
10827 static int perf_event_init_context(struct task_struct *child, int ctxn)
10829 struct perf_event_context *child_ctx, *parent_ctx;
10830 struct perf_event_context *cloned_ctx;
10831 struct perf_event *event;
10832 struct task_struct *parent = current;
10833 int inherited_all = 1;
10834 unsigned long flags;
10837 if (likely(!parent->perf_event_ctxp[ctxn]))
10841 * If the parent's context is a clone, pin it so it won't get
10842 * swapped under us.
10844 parent_ctx = perf_pin_task_context(parent, ctxn);
10849 * No need to check if parent_ctx != NULL here; since we saw
10850 * it non-NULL earlier, the only reason for it to become NULL
10851 * is if we exit, and since we're currently in the middle of
10852 * a fork we can't be exiting at the same time.
10856 * Lock the parent list. No need to lock the child - not PID
10857 * hashed yet and not running, so nobody can access it.
10859 mutex_lock(&parent_ctx->mutex);
10862 * We dont have to disable NMIs - we are only looking at
10863 * the list, not manipulating it:
10865 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
10866 ret = inherit_task_group(event, parent, parent_ctx,
10867 child, ctxn, &inherited_all);
10873 * We can't hold ctx->lock when iterating the ->flexible_group list due
10874 * to allocations, but we need to prevent rotation because
10875 * rotate_ctx() will change the list from interrupt context.
10877 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10878 parent_ctx->rotate_disable = 1;
10879 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10881 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
10882 ret = inherit_task_group(event, parent, parent_ctx,
10883 child, ctxn, &inherited_all);
10888 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
10889 parent_ctx->rotate_disable = 0;
10891 child_ctx = child->perf_event_ctxp[ctxn];
10893 if (child_ctx && inherited_all) {
10895 * Mark the child context as a clone of the parent
10896 * context, or of whatever the parent is a clone of.
10898 * Note that if the parent is a clone, the holding of
10899 * parent_ctx->lock avoids it from being uncloned.
10901 cloned_ctx = parent_ctx->parent_ctx;
10903 child_ctx->parent_ctx = cloned_ctx;
10904 child_ctx->parent_gen = parent_ctx->parent_gen;
10906 child_ctx->parent_ctx = parent_ctx;
10907 child_ctx->parent_gen = parent_ctx->generation;
10909 get_ctx(child_ctx->parent_ctx);
10912 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
10914 mutex_unlock(&parent_ctx->mutex);
10916 perf_unpin_context(parent_ctx);
10917 put_ctx(parent_ctx);
10923 * Initialize the perf_event context in task_struct
10925 int perf_event_init_task(struct task_struct *child)
10929 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
10930 mutex_init(&child->perf_event_mutex);
10931 INIT_LIST_HEAD(&child->perf_event_list);
10933 for_each_task_context_nr(ctxn) {
10934 ret = perf_event_init_context(child, ctxn);
10936 perf_event_free_task(child);
10944 static void __init perf_event_init_all_cpus(void)
10946 struct swevent_htable *swhash;
10949 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
10951 for_each_possible_cpu(cpu) {
10952 swhash = &per_cpu(swevent_htable, cpu);
10953 mutex_init(&swhash->hlist_mutex);
10954 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
10956 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
10957 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
10959 #ifdef CONFIG_CGROUP_PERF
10960 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
10962 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
10966 void perf_swevent_init_cpu(unsigned int cpu)
10968 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
10970 mutex_lock(&swhash->hlist_mutex);
10971 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
10972 struct swevent_hlist *hlist;
10974 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
10976 rcu_assign_pointer(swhash->swevent_hlist, hlist);
10978 mutex_unlock(&swhash->hlist_mutex);
10981 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
10982 static void __perf_event_exit_context(void *__info)
10984 struct perf_event_context *ctx = __info;
10985 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
10986 struct perf_event *event;
10988 raw_spin_lock(&ctx->lock);
10989 list_for_each_entry(event, &ctx->event_list, event_entry)
10990 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
10991 raw_spin_unlock(&ctx->lock);
10994 static void perf_event_exit_cpu_context(int cpu)
10996 struct perf_cpu_context *cpuctx;
10997 struct perf_event_context *ctx;
11000 mutex_lock(&pmus_lock);
11001 list_for_each_entry(pmu, &pmus, entry) {
11002 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11003 ctx = &cpuctx->ctx;
11005 mutex_lock(&ctx->mutex);
11006 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11007 cpuctx->online = 0;
11008 mutex_unlock(&ctx->mutex);
11010 cpumask_clear_cpu(cpu, perf_online_mask);
11011 mutex_unlock(&pmus_lock);
11015 static void perf_event_exit_cpu_context(int cpu) { }
11019 int perf_event_init_cpu(unsigned int cpu)
11021 struct perf_cpu_context *cpuctx;
11022 struct perf_event_context *ctx;
11025 perf_swevent_init_cpu(cpu);
11027 mutex_lock(&pmus_lock);
11028 cpumask_set_cpu(cpu, perf_online_mask);
11029 list_for_each_entry(pmu, &pmus, entry) {
11030 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11031 ctx = &cpuctx->ctx;
11033 mutex_lock(&ctx->mutex);
11034 cpuctx->online = 1;
11035 mutex_unlock(&ctx->mutex);
11037 mutex_unlock(&pmus_lock);
11042 int perf_event_exit_cpu(unsigned int cpu)
11044 perf_event_exit_cpu_context(cpu);
11049 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11053 for_each_online_cpu(cpu)
11054 perf_event_exit_cpu(cpu);
11060 * Run the perf reboot notifier at the very last possible moment so that
11061 * the generic watchdog code runs as long as possible.
11063 static struct notifier_block perf_reboot_notifier = {
11064 .notifier_call = perf_reboot,
11065 .priority = INT_MIN,
11068 void __init perf_event_init(void)
11072 idr_init(&pmu_idr);
11074 perf_event_init_all_cpus();
11075 init_srcu_struct(&pmus_srcu);
11076 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11077 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11078 perf_pmu_register(&perf_task_clock, NULL, -1);
11079 perf_tp_register();
11080 perf_event_init_cpu(smp_processor_id());
11081 register_reboot_notifier(&perf_reboot_notifier);
11083 ret = init_hw_breakpoint();
11084 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11087 * Build time assertion that we keep the data_head at the intended
11088 * location. IOW, validation we got the __reserved[] size right.
11090 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11094 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11097 struct perf_pmu_events_attr *pmu_attr =
11098 container_of(attr, struct perf_pmu_events_attr, attr);
11100 if (pmu_attr->event_str)
11101 return sprintf(page, "%s\n", pmu_attr->event_str);
11105 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11107 static int __init perf_event_sysfs_init(void)
11112 mutex_lock(&pmus_lock);
11114 ret = bus_register(&pmu_bus);
11118 list_for_each_entry(pmu, &pmus, entry) {
11119 if (!pmu->name || pmu->type < 0)
11122 ret = pmu_dev_alloc(pmu);
11123 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11125 pmu_bus_running = 1;
11129 mutex_unlock(&pmus_lock);
11133 device_initcall(perf_event_sysfs_init);
11135 #ifdef CONFIG_CGROUP_PERF
11136 static struct cgroup_subsys_state *
11137 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11139 struct perf_cgroup *jc;
11141 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11143 return ERR_PTR(-ENOMEM);
11145 jc->info = alloc_percpu(struct perf_cgroup_info);
11148 return ERR_PTR(-ENOMEM);
11154 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11156 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11158 free_percpu(jc->info);
11162 static int __perf_cgroup_move(void *info)
11164 struct task_struct *task = info;
11166 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11171 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11173 struct task_struct *task;
11174 struct cgroup_subsys_state *css;
11176 cgroup_taskset_for_each(task, css, tset)
11177 task_function_call(task, __perf_cgroup_move, task);
11180 struct cgroup_subsys perf_event_cgrp_subsys = {
11181 .css_alloc = perf_cgroup_css_alloc,
11182 .css_free = perf_cgroup_css_free,
11183 .attach = perf_cgroup_attach,
11185 * Implicitly enable on dfl hierarchy so that perf events can
11186 * always be filtered by cgroup2 path as long as perf_event
11187 * controller is not mounted on a legacy hierarchy.
11189 .implicit_on_dfl = true,
11191 #endif /* CONFIG_CGROUP_PERF */