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>
50 #include <asm/irq_regs.h>
52 static struct workqueue_struct *perf_wq;
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
74 tfc->ret = tfc->func(tfc->info);
78 * task_function_call - call a function on the cpu on which a task runs
79 * @p: the task to evaluate
80 * @func: the function to be called
81 * @info: the function call argument
83 * Calls the function @func when the task is currently running. This might
84 * be on the current CPU, which just calls the function directly
86 * returns: @func return value, or
87 * -ESRCH - when the process isn't running
88 * -EAGAIN - when the process moved away
91 task_function_call(struct task_struct *p, remote_function_f func, void *info)
93 struct remote_function_call data = {
97 .ret = -ESRCH, /* No such (running) process */
101 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
107 * cpu_function_call - call a function on the cpu
108 * @func: the function to be called
109 * @info: the function call argument
111 * Calls the function @func on the remote cpu.
113 * returns: @func return value or -ENXIO when the cpu is offline
115 static int cpu_function_call(int cpu, remote_function_f func, void *info)
117 struct remote_function_call data = {
121 .ret = -ENXIO, /* No such CPU */
124 smp_call_function_single(cpu, remote_function, &data, 1);
129 #define EVENT_OWNER_KERNEL ((void *) -1)
131 static bool is_kernel_event(struct perf_event *event)
133 return event->owner == EVENT_OWNER_KERNEL;
136 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
137 PERF_FLAG_FD_OUTPUT |\
138 PERF_FLAG_PID_CGROUP |\
139 PERF_FLAG_FD_CLOEXEC)
142 * branch priv levels that need permission checks
144 #define PERF_SAMPLE_BRANCH_PERM_PLM \
145 (PERF_SAMPLE_BRANCH_KERNEL |\
146 PERF_SAMPLE_BRANCH_HV)
149 EVENT_FLEXIBLE = 0x1,
151 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
155 * perf_sched_events : >0 events exist
156 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
158 struct static_key_deferred perf_sched_events __read_mostly;
159 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
160 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
162 static atomic_t nr_mmap_events __read_mostly;
163 static atomic_t nr_comm_events __read_mostly;
164 static atomic_t nr_task_events __read_mostly;
165 static atomic_t nr_freq_events __read_mostly;
166 static atomic_t nr_switch_events __read_mostly;
168 static LIST_HEAD(pmus);
169 static DEFINE_MUTEX(pmus_lock);
170 static struct srcu_struct pmus_srcu;
173 * perf event paranoia level:
174 * -1 - not paranoid at all
175 * 0 - disallow raw tracepoint access for unpriv
176 * 1 - disallow cpu events for unpriv
177 * 2 - disallow kernel profiling for unpriv
178 * 3 - disallow all unpriv perf event use
180 #ifdef CONFIG_SECURITY_PERF_EVENTS_RESTRICT
181 int sysctl_perf_event_paranoid __read_mostly = 3;
183 int sysctl_perf_event_paranoid __read_mostly = 1;
186 /* Minimum for 512 kiB + 1 user control page */
187 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
190 * max perf event sample rate
192 #define DEFAULT_MAX_SAMPLE_RATE 100000
193 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
194 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
196 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
198 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
199 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
201 static int perf_sample_allowed_ns __read_mostly =
202 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
204 static void update_perf_cpu_limits(void)
206 u64 tmp = perf_sample_period_ns;
208 tmp *= sysctl_perf_cpu_time_max_percent;
210 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
213 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
215 int perf_proc_update_handler(struct ctl_table *table, int write,
216 void __user *buffer, size_t *lenp,
219 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
224 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
225 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
226 update_perf_cpu_limits();
231 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
233 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
234 void __user *buffer, size_t *lenp,
237 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
242 update_perf_cpu_limits();
248 * perf samples are done in some very critical code paths (NMIs).
249 * If they take too much CPU time, the system can lock up and not
250 * get any real work done. This will drop the sample rate when
251 * we detect that events are taking too long.
253 #define NR_ACCUMULATED_SAMPLES 128
254 static DEFINE_PER_CPU(u64, running_sample_length);
256 static void perf_duration_warn(struct irq_work *w)
258 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
259 u64 avg_local_sample_len;
260 u64 local_samples_len;
262 local_samples_len = __this_cpu_read(running_sample_length);
263 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
265 printk_ratelimited(KERN_WARNING
266 "perf interrupt took too long (%lld > %lld), lowering "
267 "kernel.perf_event_max_sample_rate to %d\n",
268 avg_local_sample_len, allowed_ns >> 1,
269 sysctl_perf_event_sample_rate);
272 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
274 void perf_sample_event_took(u64 sample_len_ns)
276 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
277 u64 avg_local_sample_len;
278 u64 local_samples_len;
283 /* decay the counter by 1 average sample */
284 local_samples_len = __this_cpu_read(running_sample_length);
285 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
286 local_samples_len += sample_len_ns;
287 __this_cpu_write(running_sample_length, local_samples_len);
290 * note: this will be biased artifically low until we have
291 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
292 * from having to maintain a count.
294 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
296 if (avg_local_sample_len <= allowed_ns)
299 if (max_samples_per_tick <= 1)
302 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
303 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
304 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
306 update_perf_cpu_limits();
308 if (!irq_work_queue(&perf_duration_work)) {
309 early_printk("perf interrupt took too long (%lld > %lld), lowering "
310 "kernel.perf_event_max_sample_rate to %d\n",
311 avg_local_sample_len, allowed_ns >> 1,
312 sysctl_perf_event_sample_rate);
316 static atomic64_t perf_event_id;
318 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
319 enum event_type_t event_type);
321 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
322 enum event_type_t event_type,
323 struct task_struct *task);
325 static void update_context_time(struct perf_event_context *ctx);
326 static u64 perf_event_time(struct perf_event *event);
328 void __weak perf_event_print_debug(void) { }
330 extern __weak const char *perf_pmu_name(void)
335 static inline u64 perf_clock(void)
337 return local_clock();
340 static inline u64 perf_event_clock(struct perf_event *event)
342 return event->clock();
345 static inline struct perf_cpu_context *
346 __get_cpu_context(struct perf_event_context *ctx)
348 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
351 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
352 struct perf_event_context *ctx)
354 raw_spin_lock(&cpuctx->ctx.lock);
356 raw_spin_lock(&ctx->lock);
359 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
360 struct perf_event_context *ctx)
363 raw_spin_unlock(&ctx->lock);
364 raw_spin_unlock(&cpuctx->ctx.lock);
367 #ifdef CONFIG_CGROUP_PERF
370 perf_cgroup_match(struct perf_event *event)
372 struct perf_event_context *ctx = event->ctx;
373 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
375 /* @event doesn't care about cgroup */
379 /* wants specific cgroup scope but @cpuctx isn't associated with any */
384 * Cgroup scoping is recursive. An event enabled for a cgroup is
385 * also enabled for all its descendant cgroups. If @cpuctx's
386 * cgroup is a descendant of @event's (the test covers identity
387 * case), it's a match.
389 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
390 event->cgrp->css.cgroup);
393 static inline void perf_detach_cgroup(struct perf_event *event)
395 css_put(&event->cgrp->css);
399 static inline int is_cgroup_event(struct perf_event *event)
401 return event->cgrp != NULL;
404 static inline u64 perf_cgroup_event_time(struct perf_event *event)
406 struct perf_cgroup_info *t;
408 t = per_cpu_ptr(event->cgrp->info, event->cpu);
412 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
414 struct perf_cgroup_info *info;
419 info = this_cpu_ptr(cgrp->info);
421 info->time += now - info->timestamp;
422 info->timestamp = now;
425 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
427 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
429 __update_cgrp_time(cgrp_out);
432 static inline void update_cgrp_time_from_event(struct perf_event *event)
434 struct perf_cgroup *cgrp;
437 * ensure we access cgroup data only when needed and
438 * when we know the cgroup is pinned (css_get)
440 if (!is_cgroup_event(event))
443 cgrp = perf_cgroup_from_task(current, event->ctx);
445 * Do not update time when cgroup is not active
447 if (cgrp == event->cgrp)
448 __update_cgrp_time(event->cgrp);
452 perf_cgroup_set_timestamp(struct task_struct *task,
453 struct perf_event_context *ctx)
455 struct perf_cgroup *cgrp;
456 struct perf_cgroup_info *info;
459 * ctx->lock held by caller
460 * ensure we do not access cgroup data
461 * unless we have the cgroup pinned (css_get)
463 if (!task || !ctx->nr_cgroups)
466 cgrp = perf_cgroup_from_task(task, ctx);
467 info = this_cpu_ptr(cgrp->info);
468 info->timestamp = ctx->timestamp;
471 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
472 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
475 * reschedule events based on the cgroup constraint of task.
477 * mode SWOUT : schedule out everything
478 * mode SWIN : schedule in based on cgroup for next
480 static void perf_cgroup_switch(struct task_struct *task, int mode)
482 struct perf_cpu_context *cpuctx;
487 * disable interrupts to avoid geting nr_cgroup
488 * changes via __perf_event_disable(). Also
491 local_irq_save(flags);
494 * we reschedule only in the presence of cgroup
495 * constrained events.
498 list_for_each_entry_rcu(pmu, &pmus, entry) {
499 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
500 if (cpuctx->unique_pmu != pmu)
501 continue; /* ensure we process each cpuctx once */
504 * perf_cgroup_events says at least one
505 * context on this CPU has cgroup events.
507 * ctx->nr_cgroups reports the number of cgroup
508 * events for a context.
510 if (cpuctx->ctx.nr_cgroups > 0) {
511 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
512 perf_pmu_disable(cpuctx->ctx.pmu);
514 if (mode & PERF_CGROUP_SWOUT) {
515 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
517 * must not be done before ctxswout due
518 * to event_filter_match() in event_sched_out()
523 if (mode & PERF_CGROUP_SWIN) {
524 WARN_ON_ONCE(cpuctx->cgrp);
526 * set cgrp before ctxsw in to allow
527 * event_filter_match() to not have to pass
529 * we pass the cpuctx->ctx to perf_cgroup_from_task()
530 * because cgorup events are only per-cpu
532 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
533 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
535 perf_pmu_enable(cpuctx->ctx.pmu);
536 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
540 local_irq_restore(flags);
543 static inline void perf_cgroup_sched_out(struct task_struct *task,
544 struct task_struct *next)
546 struct perf_cgroup *cgrp1;
547 struct perf_cgroup *cgrp2 = NULL;
551 * we come here when we know perf_cgroup_events > 0
552 * we do not need to pass the ctx here because we know
553 * we are holding the rcu lock
555 cgrp1 = perf_cgroup_from_task(task, NULL);
558 * next is NULL when called from perf_event_enable_on_exec()
559 * that will systematically cause a cgroup_switch()
562 cgrp2 = perf_cgroup_from_task(next, NULL);
565 * only schedule out current cgroup events if we know
566 * that we are switching to a different cgroup. Otherwise,
567 * do no touch the cgroup events.
570 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
575 static inline void perf_cgroup_sched_in(struct task_struct *prev,
576 struct task_struct *task)
578 struct perf_cgroup *cgrp1;
579 struct perf_cgroup *cgrp2 = NULL;
583 * we come here when we know perf_cgroup_events > 0
584 * we do not need to pass the ctx here because we know
585 * we are holding the rcu lock
587 cgrp1 = perf_cgroup_from_task(task, NULL);
589 /* prev can never be NULL */
590 cgrp2 = perf_cgroup_from_task(prev, NULL);
593 * only need to schedule in cgroup events if we are changing
594 * cgroup during ctxsw. Cgroup events were not scheduled
595 * out of ctxsw out if that was not the case.
598 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
603 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
604 struct perf_event_attr *attr,
605 struct perf_event *group_leader)
607 struct perf_cgroup *cgrp;
608 struct cgroup_subsys_state *css;
609 struct fd f = fdget(fd);
615 css = css_tryget_online_from_dir(f.file->f_path.dentry,
616 &perf_event_cgrp_subsys);
622 cgrp = container_of(css, struct perf_cgroup, css);
626 * all events in a group must monitor
627 * the same cgroup because a task belongs
628 * to only one perf cgroup at a time
630 if (group_leader && group_leader->cgrp != cgrp) {
631 perf_detach_cgroup(event);
640 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
642 struct perf_cgroup_info *t;
643 t = per_cpu_ptr(event->cgrp->info, event->cpu);
644 event->shadow_ctx_time = now - t->timestamp;
648 perf_cgroup_defer_enabled(struct perf_event *event)
651 * when the current task's perf cgroup does not match
652 * the event's, we need to remember to call the
653 * perf_mark_enable() function the first time a task with
654 * a matching perf cgroup is scheduled in.
656 if (is_cgroup_event(event) && !perf_cgroup_match(event))
657 event->cgrp_defer_enabled = 1;
661 perf_cgroup_mark_enabled(struct perf_event *event,
662 struct perf_event_context *ctx)
664 struct perf_event *sub;
665 u64 tstamp = perf_event_time(event);
667 if (!event->cgrp_defer_enabled)
670 event->cgrp_defer_enabled = 0;
672 event->tstamp_enabled = tstamp - event->total_time_enabled;
673 list_for_each_entry(sub, &event->sibling_list, group_entry) {
674 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
675 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
676 sub->cgrp_defer_enabled = 0;
680 #else /* !CONFIG_CGROUP_PERF */
683 perf_cgroup_match(struct perf_event *event)
688 static inline void perf_detach_cgroup(struct perf_event *event)
691 static inline int is_cgroup_event(struct perf_event *event)
696 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
701 static inline void update_cgrp_time_from_event(struct perf_event *event)
705 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
709 static inline void perf_cgroup_sched_out(struct task_struct *task,
710 struct task_struct *next)
714 static inline void perf_cgroup_sched_in(struct task_struct *prev,
715 struct task_struct *task)
719 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
720 struct perf_event_attr *attr,
721 struct perf_event *group_leader)
727 perf_cgroup_set_timestamp(struct task_struct *task,
728 struct perf_event_context *ctx)
733 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
738 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
742 static inline u64 perf_cgroup_event_time(struct perf_event *event)
748 perf_cgroup_defer_enabled(struct perf_event *event)
753 perf_cgroup_mark_enabled(struct perf_event *event,
754 struct perf_event_context *ctx)
760 * set default to be dependent on timer tick just
763 #define PERF_CPU_HRTIMER (1000 / HZ)
765 * function must be called with interrupts disbled
767 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
769 struct perf_cpu_context *cpuctx;
772 WARN_ON(!irqs_disabled());
774 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
775 rotations = perf_rotate_context(cpuctx);
777 raw_spin_lock(&cpuctx->hrtimer_lock);
779 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
781 cpuctx->hrtimer_active = 0;
782 raw_spin_unlock(&cpuctx->hrtimer_lock);
784 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
787 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
789 struct hrtimer *timer = &cpuctx->hrtimer;
790 struct pmu *pmu = cpuctx->ctx.pmu;
793 /* no multiplexing needed for SW PMU */
794 if (pmu->task_ctx_nr == perf_sw_context)
798 * check default is sane, if not set then force to
799 * default interval (1/tick)
801 interval = pmu->hrtimer_interval_ms;
803 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
805 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
807 raw_spin_lock_init(&cpuctx->hrtimer_lock);
808 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
809 timer->function = perf_mux_hrtimer_handler;
812 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
814 struct hrtimer *timer = &cpuctx->hrtimer;
815 struct pmu *pmu = cpuctx->ctx.pmu;
819 if (pmu->task_ctx_nr == perf_sw_context)
822 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
823 if (!cpuctx->hrtimer_active) {
824 cpuctx->hrtimer_active = 1;
825 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
826 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
828 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
833 void perf_pmu_disable(struct pmu *pmu)
835 int *count = this_cpu_ptr(pmu->pmu_disable_count);
837 pmu->pmu_disable(pmu);
840 void perf_pmu_enable(struct pmu *pmu)
842 int *count = this_cpu_ptr(pmu->pmu_disable_count);
844 pmu->pmu_enable(pmu);
847 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
850 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
851 * perf_event_task_tick() are fully serialized because they're strictly cpu
852 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
853 * disabled, while perf_event_task_tick is called from IRQ context.
855 static void perf_event_ctx_activate(struct perf_event_context *ctx)
857 struct list_head *head = this_cpu_ptr(&active_ctx_list);
859 WARN_ON(!irqs_disabled());
861 WARN_ON(!list_empty(&ctx->active_ctx_list));
863 list_add(&ctx->active_ctx_list, head);
866 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
868 WARN_ON(!irqs_disabled());
870 WARN_ON(list_empty(&ctx->active_ctx_list));
872 list_del_init(&ctx->active_ctx_list);
875 static void get_ctx(struct perf_event_context *ctx)
877 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
880 static void free_ctx(struct rcu_head *head)
882 struct perf_event_context *ctx;
884 ctx = container_of(head, struct perf_event_context, rcu_head);
885 kfree(ctx->task_ctx_data);
889 static void put_ctx(struct perf_event_context *ctx)
891 if (atomic_dec_and_test(&ctx->refcount)) {
893 put_ctx(ctx->parent_ctx);
895 put_task_struct(ctx->task);
896 call_rcu(&ctx->rcu_head, free_ctx);
901 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
902 * perf_pmu_migrate_context() we need some magic.
904 * Those places that change perf_event::ctx will hold both
905 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
907 * Lock ordering is by mutex address. There are two other sites where
908 * perf_event_context::mutex nests and those are:
910 * - perf_event_exit_task_context() [ child , 0 ]
911 * __perf_event_exit_task()
913 * put_event() [ parent, 1 ]
915 * - perf_event_init_context() [ parent, 0 ]
916 * inherit_task_group()
921 * perf_try_init_event() [ child , 1 ]
923 * While it appears there is an obvious deadlock here -- the parent and child
924 * nesting levels are inverted between the two. This is in fact safe because
925 * life-time rules separate them. That is an exiting task cannot fork, and a
926 * spawning task cannot (yet) exit.
928 * But remember that that these are parent<->child context relations, and
929 * migration does not affect children, therefore these two orderings should not
932 * The change in perf_event::ctx does not affect children (as claimed above)
933 * because the sys_perf_event_open() case will install a new event and break
934 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
935 * concerned with cpuctx and that doesn't have children.
937 * The places that change perf_event::ctx will issue:
939 * perf_remove_from_context();
941 * perf_install_in_context();
943 * to affect the change. The remove_from_context() + synchronize_rcu() should
944 * quiesce the event, after which we can install it in the new location. This
945 * means that only external vectors (perf_fops, prctl) can perturb the event
946 * while in transit. Therefore all such accessors should also acquire
947 * perf_event_context::mutex to serialize against this.
949 * However; because event->ctx can change while we're waiting to acquire
950 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
955 * task_struct::perf_event_mutex
956 * perf_event_context::mutex
957 * perf_event_context::lock
958 * perf_event::child_mutex;
959 * perf_event::mmap_mutex
962 static struct perf_event_context *
963 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
965 struct perf_event_context *ctx;
969 ctx = ACCESS_ONCE(event->ctx);
970 if (!atomic_inc_not_zero(&ctx->refcount)) {
976 mutex_lock_nested(&ctx->mutex, nesting);
977 if (event->ctx != ctx) {
978 mutex_unlock(&ctx->mutex);
986 static inline struct perf_event_context *
987 perf_event_ctx_lock(struct perf_event *event)
989 return perf_event_ctx_lock_nested(event, 0);
992 static void perf_event_ctx_unlock(struct perf_event *event,
993 struct perf_event_context *ctx)
995 mutex_unlock(&ctx->mutex);
1000 * This must be done under the ctx->lock, such as to serialize against
1001 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1002 * calling scheduler related locks and ctx->lock nests inside those.
1004 static __must_check struct perf_event_context *
1005 unclone_ctx(struct perf_event_context *ctx)
1007 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1009 lockdep_assert_held(&ctx->lock);
1012 ctx->parent_ctx = NULL;
1018 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1021 * only top level events have the pid namespace they were created in
1024 event = event->parent;
1026 return task_tgid_nr_ns(p, event->ns);
1029 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1032 * only top level events have the pid namespace they were created in
1035 event = event->parent;
1037 return task_pid_nr_ns(p, event->ns);
1041 * If we inherit events we want to return the parent event id
1044 static u64 primary_event_id(struct perf_event *event)
1049 id = event->parent->id;
1055 * Get the perf_event_context for a task and lock it.
1056 * This has to cope with with the fact that until it is locked,
1057 * the context could get moved to another task.
1059 static struct perf_event_context *
1060 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1062 struct perf_event_context *ctx;
1066 * One of the few rules of preemptible RCU is that one cannot do
1067 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1068 * part of the read side critical section was irqs-enabled -- see
1069 * rcu_read_unlock_special().
1071 * Since ctx->lock nests under rq->lock we must ensure the entire read
1072 * side critical section has interrupts disabled.
1074 local_irq_save(*flags);
1076 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1079 * If this context is a clone of another, it might
1080 * get swapped for another underneath us by
1081 * perf_event_task_sched_out, though the
1082 * rcu_read_lock() protects us from any context
1083 * getting freed. Lock the context and check if it
1084 * got swapped before we could get the lock, and retry
1085 * if so. If we locked the right context, then it
1086 * can't get swapped on us any more.
1088 raw_spin_lock(&ctx->lock);
1089 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1090 raw_spin_unlock(&ctx->lock);
1092 local_irq_restore(*flags);
1096 if (!atomic_inc_not_zero(&ctx->refcount)) {
1097 raw_spin_unlock(&ctx->lock);
1103 local_irq_restore(*flags);
1108 * Get the context for a task and increment its pin_count so it
1109 * can't get swapped to another task. This also increments its
1110 * reference count so that the context can't get freed.
1112 static struct perf_event_context *
1113 perf_pin_task_context(struct task_struct *task, int ctxn)
1115 struct perf_event_context *ctx;
1116 unsigned long flags;
1118 ctx = perf_lock_task_context(task, ctxn, &flags);
1121 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1126 static void perf_unpin_context(struct perf_event_context *ctx)
1128 unsigned long flags;
1130 raw_spin_lock_irqsave(&ctx->lock, flags);
1132 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1136 * Update the record of the current time in a context.
1138 static void update_context_time(struct perf_event_context *ctx)
1140 u64 now = perf_clock();
1142 ctx->time += now - ctx->timestamp;
1143 ctx->timestamp = now;
1146 static u64 perf_event_time(struct perf_event *event)
1148 struct perf_event_context *ctx = event->ctx;
1150 if (is_cgroup_event(event))
1151 return perf_cgroup_event_time(event);
1153 return ctx ? ctx->time : 0;
1157 * Update the total_time_enabled and total_time_running fields for a event.
1158 * The caller of this function needs to hold the ctx->lock.
1160 static void update_event_times(struct perf_event *event)
1162 struct perf_event_context *ctx = event->ctx;
1165 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1166 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1169 * in cgroup mode, time_enabled represents
1170 * the time the event was enabled AND active
1171 * tasks were in the monitored cgroup. This is
1172 * independent of the activity of the context as
1173 * there may be a mix of cgroup and non-cgroup events.
1175 * That is why we treat cgroup events differently
1178 if (is_cgroup_event(event))
1179 run_end = perf_cgroup_event_time(event);
1180 else if (ctx->is_active)
1181 run_end = ctx->time;
1183 run_end = event->tstamp_stopped;
1185 event->total_time_enabled = run_end - event->tstamp_enabled;
1187 if (event->state == PERF_EVENT_STATE_INACTIVE)
1188 run_end = event->tstamp_stopped;
1190 run_end = perf_event_time(event);
1192 event->total_time_running = run_end - event->tstamp_running;
1197 * Update total_time_enabled and total_time_running for all events in a group.
1199 static void update_group_times(struct perf_event *leader)
1201 struct perf_event *event;
1203 update_event_times(leader);
1204 list_for_each_entry(event, &leader->sibling_list, group_entry)
1205 update_event_times(event);
1208 static struct list_head *
1209 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1211 if (event->attr.pinned)
1212 return &ctx->pinned_groups;
1214 return &ctx->flexible_groups;
1218 * Add a event from the lists for its context.
1219 * Must be called with ctx->mutex and ctx->lock held.
1222 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1224 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1225 event->attach_state |= PERF_ATTACH_CONTEXT;
1228 * If we're a stand alone event or group leader, we go to the context
1229 * list, group events are kept attached to the group so that
1230 * perf_group_detach can, at all times, locate all siblings.
1232 if (event->group_leader == event) {
1233 struct list_head *list;
1235 if (is_software_event(event))
1236 event->group_flags |= PERF_GROUP_SOFTWARE;
1238 list = ctx_group_list(event, ctx);
1239 list_add_tail(&event->group_entry, list);
1242 if (is_cgroup_event(event))
1245 list_add_rcu(&event->event_entry, &ctx->event_list);
1247 if (event->attr.inherit_stat)
1254 * Initialize event state based on the perf_event_attr::disabled.
1256 static inline void perf_event__state_init(struct perf_event *event)
1258 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1259 PERF_EVENT_STATE_INACTIVE;
1262 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1264 int entry = sizeof(u64); /* value */
1268 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1269 size += sizeof(u64);
1271 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1272 size += sizeof(u64);
1274 if (event->attr.read_format & PERF_FORMAT_ID)
1275 entry += sizeof(u64);
1277 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1279 size += sizeof(u64);
1283 event->read_size = size;
1286 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1288 struct perf_sample_data *data;
1291 if (sample_type & PERF_SAMPLE_IP)
1292 size += sizeof(data->ip);
1294 if (sample_type & PERF_SAMPLE_ADDR)
1295 size += sizeof(data->addr);
1297 if (sample_type & PERF_SAMPLE_PERIOD)
1298 size += sizeof(data->period);
1300 if (sample_type & PERF_SAMPLE_WEIGHT)
1301 size += sizeof(data->weight);
1303 if (sample_type & PERF_SAMPLE_READ)
1304 size += event->read_size;
1306 if (sample_type & PERF_SAMPLE_DATA_SRC)
1307 size += sizeof(data->data_src.val);
1309 if (sample_type & PERF_SAMPLE_TRANSACTION)
1310 size += sizeof(data->txn);
1312 event->header_size = size;
1316 * Called at perf_event creation and when events are attached/detached from a
1319 static void perf_event__header_size(struct perf_event *event)
1321 __perf_event_read_size(event,
1322 event->group_leader->nr_siblings);
1323 __perf_event_header_size(event, event->attr.sample_type);
1326 static void perf_event__id_header_size(struct perf_event *event)
1328 struct perf_sample_data *data;
1329 u64 sample_type = event->attr.sample_type;
1332 if (sample_type & PERF_SAMPLE_TID)
1333 size += sizeof(data->tid_entry);
1335 if (sample_type & PERF_SAMPLE_TIME)
1336 size += sizeof(data->time);
1338 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1339 size += sizeof(data->id);
1341 if (sample_type & PERF_SAMPLE_ID)
1342 size += sizeof(data->id);
1344 if (sample_type & PERF_SAMPLE_STREAM_ID)
1345 size += sizeof(data->stream_id);
1347 if (sample_type & PERF_SAMPLE_CPU)
1348 size += sizeof(data->cpu_entry);
1350 event->id_header_size = size;
1353 static bool perf_event_validate_size(struct perf_event *event)
1356 * The values computed here will be over-written when we actually
1359 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1360 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1361 perf_event__id_header_size(event);
1364 * Sum the lot; should not exceed the 64k limit we have on records.
1365 * Conservative limit to allow for callchains and other variable fields.
1367 if (event->read_size + event->header_size +
1368 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1374 static void perf_group_attach(struct perf_event *event)
1376 struct perf_event *group_leader = event->group_leader, *pos;
1379 * We can have double attach due to group movement in perf_event_open.
1381 if (event->attach_state & PERF_ATTACH_GROUP)
1384 event->attach_state |= PERF_ATTACH_GROUP;
1386 if (group_leader == event)
1389 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1391 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1392 !is_software_event(event))
1393 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1395 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1396 group_leader->nr_siblings++;
1398 perf_event__header_size(group_leader);
1400 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1401 perf_event__header_size(pos);
1405 * Remove a event from the lists for its context.
1406 * Must be called with ctx->mutex and ctx->lock held.
1409 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1411 struct perf_cpu_context *cpuctx;
1413 WARN_ON_ONCE(event->ctx != ctx);
1414 lockdep_assert_held(&ctx->lock);
1417 * We can have double detach due to exit/hot-unplug + close.
1419 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1422 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1424 if (is_cgroup_event(event)) {
1426 cpuctx = __get_cpu_context(ctx);
1428 * if there are no more cgroup events
1429 * then cler cgrp to avoid stale pointer
1430 * in update_cgrp_time_from_cpuctx()
1432 if (!ctx->nr_cgroups)
1433 cpuctx->cgrp = NULL;
1437 if (event->attr.inherit_stat)
1440 list_del_rcu(&event->event_entry);
1442 if (event->group_leader == event)
1443 list_del_init(&event->group_entry);
1445 update_group_times(event);
1448 * If event was in error state, then keep it
1449 * that way, otherwise bogus counts will be
1450 * returned on read(). The only way to get out
1451 * of error state is by explicit re-enabling
1454 if (event->state > PERF_EVENT_STATE_OFF)
1455 event->state = PERF_EVENT_STATE_OFF;
1460 static void perf_group_detach(struct perf_event *event)
1462 struct perf_event *sibling, *tmp;
1463 struct list_head *list = NULL;
1466 * We can have double detach due to exit/hot-unplug + close.
1468 if (!(event->attach_state & PERF_ATTACH_GROUP))
1471 event->attach_state &= ~PERF_ATTACH_GROUP;
1474 * If this is a sibling, remove it from its group.
1476 if (event->group_leader != event) {
1477 list_del_init(&event->group_entry);
1478 event->group_leader->nr_siblings--;
1482 if (!list_empty(&event->group_entry))
1483 list = &event->group_entry;
1486 * If this was a group event with sibling events then
1487 * upgrade the siblings to singleton events by adding them
1488 * to whatever list we are on.
1490 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1492 list_move_tail(&sibling->group_entry, list);
1493 sibling->group_leader = sibling;
1495 /* Inherit group flags from the previous leader */
1496 sibling->group_flags = event->group_flags;
1498 WARN_ON_ONCE(sibling->ctx != event->ctx);
1502 perf_event__header_size(event->group_leader);
1504 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1505 perf_event__header_size(tmp);
1509 * User event without the task.
1511 static bool is_orphaned_event(struct perf_event *event)
1513 return event && !is_kernel_event(event) && !event->owner;
1517 * Event has a parent but parent's task finished and it's
1518 * alive only because of children holding refference.
1520 static bool is_orphaned_child(struct perf_event *event)
1522 return is_orphaned_event(event->parent);
1525 static void orphans_remove_work(struct work_struct *work);
1527 static void schedule_orphans_remove(struct perf_event_context *ctx)
1529 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1532 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1534 ctx->orphans_remove_sched = true;
1538 static int __init perf_workqueue_init(void)
1540 perf_wq = create_singlethread_workqueue("perf");
1541 WARN(!perf_wq, "failed to create perf workqueue\n");
1542 return perf_wq ? 0 : -1;
1545 core_initcall(perf_workqueue_init);
1547 static inline int pmu_filter_match(struct perf_event *event)
1549 struct pmu *pmu = event->pmu;
1550 return pmu->filter_match ? pmu->filter_match(event) : 1;
1554 event_filter_match(struct perf_event *event)
1556 return (event->cpu == -1 || event->cpu == smp_processor_id())
1557 && perf_cgroup_match(event) && pmu_filter_match(event);
1561 event_sched_out(struct perf_event *event,
1562 struct perf_cpu_context *cpuctx,
1563 struct perf_event_context *ctx)
1565 u64 tstamp = perf_event_time(event);
1568 WARN_ON_ONCE(event->ctx != ctx);
1569 lockdep_assert_held(&ctx->lock);
1572 * An event which could not be activated because of
1573 * filter mismatch still needs to have its timings
1574 * maintained, otherwise bogus information is return
1575 * via read() for time_enabled, time_running:
1577 if (event->state == PERF_EVENT_STATE_INACTIVE
1578 && !event_filter_match(event)) {
1579 delta = tstamp - event->tstamp_stopped;
1580 event->tstamp_running += delta;
1581 event->tstamp_stopped = tstamp;
1584 if (event->state != PERF_EVENT_STATE_ACTIVE)
1587 perf_pmu_disable(event->pmu);
1589 event->tstamp_stopped = tstamp;
1590 event->pmu->del(event, 0);
1592 event->state = PERF_EVENT_STATE_INACTIVE;
1593 if (event->pending_disable) {
1594 event->pending_disable = 0;
1595 event->state = PERF_EVENT_STATE_OFF;
1598 if (!is_software_event(event))
1599 cpuctx->active_oncpu--;
1600 if (!--ctx->nr_active)
1601 perf_event_ctx_deactivate(ctx);
1602 if (event->attr.freq && event->attr.sample_freq)
1604 if (event->attr.exclusive || !cpuctx->active_oncpu)
1605 cpuctx->exclusive = 0;
1607 if (is_orphaned_child(event))
1608 schedule_orphans_remove(ctx);
1610 perf_pmu_enable(event->pmu);
1614 group_sched_out(struct perf_event *group_event,
1615 struct perf_cpu_context *cpuctx,
1616 struct perf_event_context *ctx)
1618 struct perf_event *event;
1619 int state = group_event->state;
1621 event_sched_out(group_event, cpuctx, ctx);
1624 * Schedule out siblings (if any):
1626 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1627 event_sched_out(event, cpuctx, ctx);
1629 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1630 cpuctx->exclusive = 0;
1633 struct remove_event {
1634 struct perf_event *event;
1639 * Cross CPU call to remove a performance event
1641 * We disable the event on the hardware level first. After that we
1642 * remove it from the context list.
1644 static int __perf_remove_from_context(void *info)
1646 struct remove_event *re = info;
1647 struct perf_event *event = re->event;
1648 struct perf_event_context *ctx = event->ctx;
1649 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1651 raw_spin_lock(&ctx->lock);
1652 event_sched_out(event, cpuctx, ctx);
1653 if (re->detach_group)
1654 perf_group_detach(event);
1655 list_del_event(event, ctx);
1656 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1658 cpuctx->task_ctx = NULL;
1660 raw_spin_unlock(&ctx->lock);
1667 * Remove the event from a task's (or a CPU's) list of events.
1669 * CPU events are removed with a smp call. For task events we only
1670 * call when the task is on a CPU.
1672 * If event->ctx is a cloned context, callers must make sure that
1673 * every task struct that event->ctx->task could possibly point to
1674 * remains valid. This is OK when called from perf_release since
1675 * that only calls us on the top-level context, which can't be a clone.
1676 * When called from perf_event_exit_task, it's OK because the
1677 * context has been detached from its task.
1679 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1681 struct perf_event_context *ctx = event->ctx;
1682 struct task_struct *task = ctx->task;
1683 struct remove_event re = {
1685 .detach_group = detach_group,
1688 lockdep_assert_held(&ctx->mutex);
1692 * Per cpu events are removed via an smp call. The removal can
1693 * fail if the CPU is currently offline, but in that case we
1694 * already called __perf_remove_from_context from
1695 * perf_event_exit_cpu.
1697 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1702 if (!task_function_call(task, __perf_remove_from_context, &re))
1705 raw_spin_lock_irq(&ctx->lock);
1707 * If we failed to find a running task, but find the context active now
1708 * that we've acquired the ctx->lock, retry.
1710 if (ctx->is_active) {
1711 raw_spin_unlock_irq(&ctx->lock);
1713 * Reload the task pointer, it might have been changed by
1714 * a concurrent perf_event_context_sched_out().
1721 * Since the task isn't running, its safe to remove the event, us
1722 * holding the ctx->lock ensures the task won't get scheduled in.
1725 perf_group_detach(event);
1726 list_del_event(event, ctx);
1727 raw_spin_unlock_irq(&ctx->lock);
1731 * Cross CPU call to disable a performance event
1733 int __perf_event_disable(void *info)
1735 struct perf_event *event = info;
1736 struct perf_event_context *ctx = event->ctx;
1737 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1740 * If this is a per-task event, need to check whether this
1741 * event's task is the current task on this cpu.
1743 * Can trigger due to concurrent perf_event_context_sched_out()
1744 * flipping contexts around.
1746 if (ctx->task && cpuctx->task_ctx != ctx)
1749 raw_spin_lock(&ctx->lock);
1752 * If the event is on, turn it off.
1753 * If it is in error state, leave it in error state.
1755 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1756 update_context_time(ctx);
1757 update_cgrp_time_from_event(event);
1758 update_group_times(event);
1759 if (event == event->group_leader)
1760 group_sched_out(event, cpuctx, ctx);
1762 event_sched_out(event, cpuctx, ctx);
1763 event->state = PERF_EVENT_STATE_OFF;
1766 raw_spin_unlock(&ctx->lock);
1774 * If event->ctx is a cloned context, callers must make sure that
1775 * every task struct that event->ctx->task could possibly point to
1776 * remains valid. This condition is satisifed when called through
1777 * perf_event_for_each_child or perf_event_for_each because they
1778 * hold the top-level event's child_mutex, so any descendant that
1779 * goes to exit will block in sync_child_event.
1780 * When called from perf_pending_event it's OK because event->ctx
1781 * is the current context on this CPU and preemption is disabled,
1782 * hence we can't get into perf_event_task_sched_out for this context.
1784 static void _perf_event_disable(struct perf_event *event)
1786 struct perf_event_context *ctx = event->ctx;
1787 struct task_struct *task = ctx->task;
1791 * Disable the event on the cpu that it's on
1793 cpu_function_call(event->cpu, __perf_event_disable, event);
1798 if (!task_function_call(task, __perf_event_disable, event))
1801 raw_spin_lock_irq(&ctx->lock);
1803 * If the event is still active, we need to retry the cross-call.
1805 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1806 raw_spin_unlock_irq(&ctx->lock);
1808 * Reload the task pointer, it might have been changed by
1809 * a concurrent perf_event_context_sched_out().
1816 * Since we have the lock this context can't be scheduled
1817 * in, so we can change the state safely.
1819 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1820 update_group_times(event);
1821 event->state = PERF_EVENT_STATE_OFF;
1823 raw_spin_unlock_irq(&ctx->lock);
1827 * Strictly speaking kernel users cannot create groups and therefore this
1828 * interface does not need the perf_event_ctx_lock() magic.
1830 void perf_event_disable(struct perf_event *event)
1832 struct perf_event_context *ctx;
1834 ctx = perf_event_ctx_lock(event);
1835 _perf_event_disable(event);
1836 perf_event_ctx_unlock(event, ctx);
1838 EXPORT_SYMBOL_GPL(perf_event_disable);
1840 static void perf_set_shadow_time(struct perf_event *event,
1841 struct perf_event_context *ctx,
1845 * use the correct time source for the time snapshot
1847 * We could get by without this by leveraging the
1848 * fact that to get to this function, the caller
1849 * has most likely already called update_context_time()
1850 * and update_cgrp_time_xx() and thus both timestamp
1851 * are identical (or very close). Given that tstamp is,
1852 * already adjusted for cgroup, we could say that:
1853 * tstamp - ctx->timestamp
1855 * tstamp - cgrp->timestamp.
1857 * Then, in perf_output_read(), the calculation would
1858 * work with no changes because:
1859 * - event is guaranteed scheduled in
1860 * - no scheduled out in between
1861 * - thus the timestamp would be the same
1863 * But this is a bit hairy.
1865 * So instead, we have an explicit cgroup call to remain
1866 * within the time time source all along. We believe it
1867 * is cleaner and simpler to understand.
1869 if (is_cgroup_event(event))
1870 perf_cgroup_set_shadow_time(event, tstamp);
1872 event->shadow_ctx_time = tstamp - ctx->timestamp;
1875 #define MAX_INTERRUPTS (~0ULL)
1877 static void perf_log_throttle(struct perf_event *event, int enable);
1878 static void perf_log_itrace_start(struct perf_event *event);
1881 event_sched_in(struct perf_event *event,
1882 struct perf_cpu_context *cpuctx,
1883 struct perf_event_context *ctx)
1885 u64 tstamp = perf_event_time(event);
1888 lockdep_assert_held(&ctx->lock);
1890 if (event->state <= PERF_EVENT_STATE_OFF)
1893 WRITE_ONCE(event->oncpu, smp_processor_id());
1895 * Order event::oncpu write to happen before the ACTIVE state
1899 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1902 * Unthrottle events, since we scheduled we might have missed several
1903 * ticks already, also for a heavily scheduling task there is little
1904 * guarantee it'll get a tick in a timely manner.
1906 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1907 perf_log_throttle(event, 1);
1908 event->hw.interrupts = 0;
1912 * The new state must be visible before we turn it on in the hardware:
1916 perf_pmu_disable(event->pmu);
1918 perf_set_shadow_time(event, ctx, tstamp);
1920 perf_log_itrace_start(event);
1922 if (event->pmu->add(event, PERF_EF_START)) {
1923 event->state = PERF_EVENT_STATE_INACTIVE;
1929 event->tstamp_running += tstamp - event->tstamp_stopped;
1931 if (!is_software_event(event))
1932 cpuctx->active_oncpu++;
1933 if (!ctx->nr_active++)
1934 perf_event_ctx_activate(ctx);
1935 if (event->attr.freq && event->attr.sample_freq)
1938 if (event->attr.exclusive)
1939 cpuctx->exclusive = 1;
1941 if (is_orphaned_child(event))
1942 schedule_orphans_remove(ctx);
1945 perf_pmu_enable(event->pmu);
1951 group_sched_in(struct perf_event *group_event,
1952 struct perf_cpu_context *cpuctx,
1953 struct perf_event_context *ctx)
1955 struct perf_event *event, *partial_group = NULL;
1956 struct pmu *pmu = ctx->pmu;
1957 u64 now = ctx->time;
1958 bool simulate = false;
1960 if (group_event->state == PERF_EVENT_STATE_OFF)
1963 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1965 if (event_sched_in(group_event, cpuctx, ctx)) {
1966 pmu->cancel_txn(pmu);
1967 perf_mux_hrtimer_restart(cpuctx);
1972 * Schedule in siblings as one group (if any):
1974 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1975 if (event_sched_in(event, cpuctx, ctx)) {
1976 partial_group = event;
1981 if (!pmu->commit_txn(pmu))
1986 * Groups can be scheduled in as one unit only, so undo any
1987 * partial group before returning:
1988 * The events up to the failed event are scheduled out normally,
1989 * tstamp_stopped will be updated.
1991 * The failed events and the remaining siblings need to have
1992 * their timings updated as if they had gone thru event_sched_in()
1993 * and event_sched_out(). This is required to get consistent timings
1994 * across the group. This also takes care of the case where the group
1995 * could never be scheduled by ensuring tstamp_stopped is set to mark
1996 * the time the event was actually stopped, such that time delta
1997 * calculation in update_event_times() is correct.
1999 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2000 if (event == partial_group)
2004 event->tstamp_running += now - event->tstamp_stopped;
2005 event->tstamp_stopped = now;
2007 event_sched_out(event, cpuctx, ctx);
2010 event_sched_out(group_event, cpuctx, ctx);
2012 pmu->cancel_txn(pmu);
2014 perf_mux_hrtimer_restart(cpuctx);
2020 * Work out whether we can put this event group on the CPU now.
2022 static int group_can_go_on(struct perf_event *event,
2023 struct perf_cpu_context *cpuctx,
2027 * Groups consisting entirely of software events can always go on.
2029 if (event->group_flags & PERF_GROUP_SOFTWARE)
2032 * If an exclusive group is already on, no other hardware
2035 if (cpuctx->exclusive)
2038 * If this group is exclusive and there are already
2039 * events on the CPU, it can't go on.
2041 if (event->attr.exclusive && cpuctx->active_oncpu)
2044 * Otherwise, try to add it if all previous groups were able
2050 static void add_event_to_ctx(struct perf_event *event,
2051 struct perf_event_context *ctx)
2053 u64 tstamp = perf_event_time(event);
2055 list_add_event(event, ctx);
2056 perf_group_attach(event);
2057 event->tstamp_enabled = tstamp;
2058 event->tstamp_running = tstamp;
2059 event->tstamp_stopped = tstamp;
2062 static void task_ctx_sched_out(struct perf_event_context *ctx);
2064 ctx_sched_in(struct perf_event_context *ctx,
2065 struct perf_cpu_context *cpuctx,
2066 enum event_type_t event_type,
2067 struct task_struct *task);
2069 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2070 struct perf_event_context *ctx,
2071 struct task_struct *task)
2073 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2075 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2076 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2078 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2082 * Cross CPU call to install and enable a performance event
2084 * Must be called with ctx->mutex held
2086 static int __perf_install_in_context(void *info)
2088 struct perf_event *event = info;
2089 struct perf_event_context *ctx = event->ctx;
2090 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2091 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2092 struct task_struct *task = current;
2094 perf_ctx_lock(cpuctx, task_ctx);
2095 perf_pmu_disable(cpuctx->ctx.pmu);
2098 * If there was an active task_ctx schedule it out.
2101 task_ctx_sched_out(task_ctx);
2104 * If the context we're installing events in is not the
2105 * active task_ctx, flip them.
2107 if (ctx->task && task_ctx != ctx) {
2109 raw_spin_unlock(&task_ctx->lock);
2110 raw_spin_lock(&ctx->lock);
2115 cpuctx->task_ctx = task_ctx;
2116 task = task_ctx->task;
2119 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2121 update_context_time(ctx);
2123 * update cgrp time only if current cgrp
2124 * matches event->cgrp. Must be done before
2125 * calling add_event_to_ctx()
2127 update_cgrp_time_from_event(event);
2129 add_event_to_ctx(event, ctx);
2132 * Schedule everything back in
2134 perf_event_sched_in(cpuctx, task_ctx, task);
2136 perf_pmu_enable(cpuctx->ctx.pmu);
2137 perf_ctx_unlock(cpuctx, task_ctx);
2143 * Attach a performance event to a context
2145 * First we add the event to the list with the hardware enable bit
2146 * in event->hw_config cleared.
2148 * If the event is attached to a task which is on a CPU we use a smp
2149 * call to enable it in the task context. The task might have been
2150 * scheduled away, but we check this in the smp call again.
2153 perf_install_in_context(struct perf_event_context *ctx,
2154 struct perf_event *event,
2157 struct task_struct *task = ctx->task;
2159 lockdep_assert_held(&ctx->mutex);
2162 if (event->cpu != -1)
2167 * Per cpu events are installed via an smp call and
2168 * the install is always successful.
2170 cpu_function_call(cpu, __perf_install_in_context, event);
2175 if (!task_function_call(task, __perf_install_in_context, event))
2178 raw_spin_lock_irq(&ctx->lock);
2180 * If we failed to find a running task, but find the context active now
2181 * that we've acquired the ctx->lock, retry.
2183 if (ctx->is_active) {
2184 raw_spin_unlock_irq(&ctx->lock);
2186 * Reload the task pointer, it might have been changed by
2187 * a concurrent perf_event_context_sched_out().
2194 * Since the task isn't running, its safe to add the event, us holding
2195 * the ctx->lock ensures the task won't get scheduled in.
2197 add_event_to_ctx(event, ctx);
2198 raw_spin_unlock_irq(&ctx->lock);
2202 * Put a event into inactive state and update time fields.
2203 * Enabling the leader of a group effectively enables all
2204 * the group members that aren't explicitly disabled, so we
2205 * have to update their ->tstamp_enabled also.
2206 * Note: this works for group members as well as group leaders
2207 * since the non-leader members' sibling_lists will be empty.
2209 static void __perf_event_mark_enabled(struct perf_event *event)
2211 struct perf_event *sub;
2212 u64 tstamp = perf_event_time(event);
2214 event->state = PERF_EVENT_STATE_INACTIVE;
2215 event->tstamp_enabled = tstamp - event->total_time_enabled;
2216 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2217 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2218 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2223 * Cross CPU call to enable a performance event
2225 static int __perf_event_enable(void *info)
2227 struct perf_event *event = info;
2228 struct perf_event_context *ctx = event->ctx;
2229 struct perf_event *leader = event->group_leader;
2230 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2234 * There's a time window between 'ctx->is_active' check
2235 * in perf_event_enable function and this place having:
2237 * - ctx->lock unlocked
2239 * where the task could be killed and 'ctx' deactivated
2240 * by perf_event_exit_task.
2242 if (!ctx->is_active)
2245 raw_spin_lock(&ctx->lock);
2246 update_context_time(ctx);
2248 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2252 * set current task's cgroup time reference point
2254 perf_cgroup_set_timestamp(current, ctx);
2256 __perf_event_mark_enabled(event);
2258 if (!event_filter_match(event)) {
2259 if (is_cgroup_event(event))
2260 perf_cgroup_defer_enabled(event);
2265 * If the event is in a group and isn't the group leader,
2266 * then don't put it on unless the group is on.
2268 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2271 if (!group_can_go_on(event, cpuctx, 1)) {
2274 if (event == leader)
2275 err = group_sched_in(event, cpuctx, ctx);
2277 err = event_sched_in(event, cpuctx, ctx);
2282 * If this event can't go on and it's part of a
2283 * group, then the whole group has to come off.
2285 if (leader != event) {
2286 group_sched_out(leader, cpuctx, ctx);
2287 perf_mux_hrtimer_restart(cpuctx);
2289 if (leader->attr.pinned) {
2290 update_group_times(leader);
2291 leader->state = PERF_EVENT_STATE_ERROR;
2296 raw_spin_unlock(&ctx->lock);
2304 * If event->ctx is a cloned context, callers must make sure that
2305 * every task struct that event->ctx->task could possibly point to
2306 * remains valid. This condition is satisfied when called through
2307 * perf_event_for_each_child or perf_event_for_each as described
2308 * for perf_event_disable.
2310 static void _perf_event_enable(struct perf_event *event)
2312 struct perf_event_context *ctx = event->ctx;
2313 struct task_struct *task = ctx->task;
2317 * Enable the event on the cpu that it's on
2319 cpu_function_call(event->cpu, __perf_event_enable, event);
2323 raw_spin_lock_irq(&ctx->lock);
2324 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2328 * If the event is in error state, clear that first.
2329 * That way, if we see the event in error state below, we
2330 * know that it has gone back into error state, as distinct
2331 * from the task having been scheduled away before the
2332 * cross-call arrived.
2334 if (event->state == PERF_EVENT_STATE_ERROR)
2335 event->state = PERF_EVENT_STATE_OFF;
2338 if (!ctx->is_active) {
2339 __perf_event_mark_enabled(event);
2343 raw_spin_unlock_irq(&ctx->lock);
2345 if (!task_function_call(task, __perf_event_enable, event))
2348 raw_spin_lock_irq(&ctx->lock);
2351 * If the context is active and the event is still off,
2352 * we need to retry the cross-call.
2354 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2356 * task could have been flipped by a concurrent
2357 * perf_event_context_sched_out()
2364 raw_spin_unlock_irq(&ctx->lock);
2368 * See perf_event_disable();
2370 void perf_event_enable(struct perf_event *event)
2372 struct perf_event_context *ctx;
2374 ctx = perf_event_ctx_lock(event);
2375 _perf_event_enable(event);
2376 perf_event_ctx_unlock(event, ctx);
2378 EXPORT_SYMBOL_GPL(perf_event_enable);
2380 static int __perf_event_stop(void *info)
2382 struct perf_event *event = info;
2384 /* for AUX events, our job is done if the event is already inactive */
2385 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2388 /* matches smp_wmb() in event_sched_in() */
2392 * There is a window with interrupts enabled before we get here,
2393 * so we need to check again lest we try to stop another CPU's event.
2395 if (READ_ONCE(event->oncpu) != smp_processor_id())
2398 event->pmu->stop(event, PERF_EF_UPDATE);
2403 static int _perf_event_refresh(struct perf_event *event, int refresh)
2406 * not supported on inherited events
2408 if (event->attr.inherit || !is_sampling_event(event))
2411 atomic_add(refresh, &event->event_limit);
2412 _perf_event_enable(event);
2418 * See perf_event_disable()
2420 int perf_event_refresh(struct perf_event *event, int refresh)
2422 struct perf_event_context *ctx;
2425 ctx = perf_event_ctx_lock(event);
2426 ret = _perf_event_refresh(event, refresh);
2427 perf_event_ctx_unlock(event, ctx);
2431 EXPORT_SYMBOL_GPL(perf_event_refresh);
2433 static void ctx_sched_out(struct perf_event_context *ctx,
2434 struct perf_cpu_context *cpuctx,
2435 enum event_type_t event_type)
2437 struct perf_event *event;
2438 int is_active = ctx->is_active;
2440 ctx->is_active &= ~event_type;
2441 if (likely(!ctx->nr_events))
2444 update_context_time(ctx);
2445 update_cgrp_time_from_cpuctx(cpuctx);
2446 if (!ctx->nr_active)
2449 perf_pmu_disable(ctx->pmu);
2450 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2451 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2452 group_sched_out(event, cpuctx, ctx);
2455 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2456 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2457 group_sched_out(event, cpuctx, ctx);
2459 perf_pmu_enable(ctx->pmu);
2463 * Test whether two contexts are equivalent, i.e. whether they have both been
2464 * cloned from the same version of the same context.
2466 * Equivalence is measured using a generation number in the context that is
2467 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2468 * and list_del_event().
2470 static int context_equiv(struct perf_event_context *ctx1,
2471 struct perf_event_context *ctx2)
2473 lockdep_assert_held(&ctx1->lock);
2474 lockdep_assert_held(&ctx2->lock);
2476 /* Pinning disables the swap optimization */
2477 if (ctx1->pin_count || ctx2->pin_count)
2480 /* If ctx1 is the parent of ctx2 */
2481 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2484 /* If ctx2 is the parent of ctx1 */
2485 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2489 * If ctx1 and ctx2 have the same parent; we flatten the parent
2490 * hierarchy, see perf_event_init_context().
2492 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2493 ctx1->parent_gen == ctx2->parent_gen)
2500 static void __perf_event_sync_stat(struct perf_event *event,
2501 struct perf_event *next_event)
2505 if (!event->attr.inherit_stat)
2509 * Update the event value, we cannot use perf_event_read()
2510 * because we're in the middle of a context switch and have IRQs
2511 * disabled, which upsets smp_call_function_single(), however
2512 * we know the event must be on the current CPU, therefore we
2513 * don't need to use it.
2515 switch (event->state) {
2516 case PERF_EVENT_STATE_ACTIVE:
2517 event->pmu->read(event);
2520 case PERF_EVENT_STATE_INACTIVE:
2521 update_event_times(event);
2529 * In order to keep per-task stats reliable we need to flip the event
2530 * values when we flip the contexts.
2532 value = local64_read(&next_event->count);
2533 value = local64_xchg(&event->count, value);
2534 local64_set(&next_event->count, value);
2536 swap(event->total_time_enabled, next_event->total_time_enabled);
2537 swap(event->total_time_running, next_event->total_time_running);
2540 * Since we swizzled the values, update the user visible data too.
2542 perf_event_update_userpage(event);
2543 perf_event_update_userpage(next_event);
2546 static void perf_event_sync_stat(struct perf_event_context *ctx,
2547 struct perf_event_context *next_ctx)
2549 struct perf_event *event, *next_event;
2554 update_context_time(ctx);
2556 event = list_first_entry(&ctx->event_list,
2557 struct perf_event, event_entry);
2559 next_event = list_first_entry(&next_ctx->event_list,
2560 struct perf_event, event_entry);
2562 while (&event->event_entry != &ctx->event_list &&
2563 &next_event->event_entry != &next_ctx->event_list) {
2565 __perf_event_sync_stat(event, next_event);
2567 event = list_next_entry(event, event_entry);
2568 next_event = list_next_entry(next_event, event_entry);
2572 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2573 struct task_struct *next)
2575 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2576 struct perf_event_context *next_ctx;
2577 struct perf_event_context *parent, *next_parent;
2578 struct perf_cpu_context *cpuctx;
2584 cpuctx = __get_cpu_context(ctx);
2585 if (!cpuctx->task_ctx)
2589 next_ctx = next->perf_event_ctxp[ctxn];
2593 parent = rcu_dereference(ctx->parent_ctx);
2594 next_parent = rcu_dereference(next_ctx->parent_ctx);
2596 /* If neither context have a parent context; they cannot be clones. */
2597 if (!parent && !next_parent)
2600 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2602 * Looks like the two contexts are clones, so we might be
2603 * able to optimize the context switch. We lock both
2604 * contexts and check that they are clones under the
2605 * lock (including re-checking that neither has been
2606 * uncloned in the meantime). It doesn't matter which
2607 * order we take the locks because no other cpu could
2608 * be trying to lock both of these tasks.
2610 raw_spin_lock(&ctx->lock);
2611 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2612 if (context_equiv(ctx, next_ctx)) {
2614 * XXX do we need a memory barrier of sorts
2615 * wrt to rcu_dereference() of perf_event_ctxp
2617 task->perf_event_ctxp[ctxn] = next_ctx;
2618 next->perf_event_ctxp[ctxn] = ctx;
2620 next_ctx->task = task;
2622 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2626 perf_event_sync_stat(ctx, next_ctx);
2628 raw_spin_unlock(&next_ctx->lock);
2629 raw_spin_unlock(&ctx->lock);
2635 raw_spin_lock(&ctx->lock);
2636 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2637 cpuctx->task_ctx = NULL;
2638 raw_spin_unlock(&ctx->lock);
2642 void perf_sched_cb_dec(struct pmu *pmu)
2644 this_cpu_dec(perf_sched_cb_usages);
2647 void perf_sched_cb_inc(struct pmu *pmu)
2649 this_cpu_inc(perf_sched_cb_usages);
2653 * This function provides the context switch callback to the lower code
2654 * layer. It is invoked ONLY when the context switch callback is enabled.
2656 static void perf_pmu_sched_task(struct task_struct *prev,
2657 struct task_struct *next,
2660 struct perf_cpu_context *cpuctx;
2662 unsigned long flags;
2667 local_irq_save(flags);
2671 list_for_each_entry_rcu(pmu, &pmus, entry) {
2672 if (pmu->sched_task) {
2673 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2675 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2677 perf_pmu_disable(pmu);
2679 pmu->sched_task(cpuctx->task_ctx, sched_in);
2681 perf_pmu_enable(pmu);
2683 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2689 local_irq_restore(flags);
2692 static void perf_event_switch(struct task_struct *task,
2693 struct task_struct *next_prev, bool sched_in);
2695 #define for_each_task_context_nr(ctxn) \
2696 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2699 * Called from scheduler to remove the events of the current task,
2700 * with interrupts disabled.
2702 * We stop each event and update the event value in event->count.
2704 * This does not protect us against NMI, but disable()
2705 * sets the disabled bit in the control field of event _before_
2706 * accessing the event control register. If a NMI hits, then it will
2707 * not restart the event.
2709 void __perf_event_task_sched_out(struct task_struct *task,
2710 struct task_struct *next)
2714 if (__this_cpu_read(perf_sched_cb_usages))
2715 perf_pmu_sched_task(task, next, false);
2717 if (atomic_read(&nr_switch_events))
2718 perf_event_switch(task, next, false);
2720 for_each_task_context_nr(ctxn)
2721 perf_event_context_sched_out(task, ctxn, next);
2724 * if cgroup events exist on this CPU, then we need
2725 * to check if we have to switch out PMU state.
2726 * cgroup event are system-wide mode only
2728 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2729 perf_cgroup_sched_out(task, next);
2732 static void task_ctx_sched_out(struct perf_event_context *ctx)
2734 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2736 if (!cpuctx->task_ctx)
2739 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2742 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2743 cpuctx->task_ctx = NULL;
2747 * Called with IRQs disabled
2749 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2750 enum event_type_t event_type)
2752 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2756 ctx_pinned_sched_in(struct perf_event_context *ctx,
2757 struct perf_cpu_context *cpuctx)
2759 struct perf_event *event;
2761 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2762 if (event->state <= PERF_EVENT_STATE_OFF)
2764 if (!event_filter_match(event))
2767 /* may need to reset tstamp_enabled */
2768 if (is_cgroup_event(event))
2769 perf_cgroup_mark_enabled(event, ctx);
2771 if (group_can_go_on(event, cpuctx, 1))
2772 group_sched_in(event, cpuctx, ctx);
2775 * If this pinned group hasn't been scheduled,
2776 * put it in error state.
2778 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2779 update_group_times(event);
2780 event->state = PERF_EVENT_STATE_ERROR;
2786 ctx_flexible_sched_in(struct perf_event_context *ctx,
2787 struct perf_cpu_context *cpuctx)
2789 struct perf_event *event;
2792 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2793 /* Ignore events in OFF or ERROR state */
2794 if (event->state <= PERF_EVENT_STATE_OFF)
2797 * Listen to the 'cpu' scheduling filter constraint
2800 if (!event_filter_match(event))
2803 /* may need to reset tstamp_enabled */
2804 if (is_cgroup_event(event))
2805 perf_cgroup_mark_enabled(event, ctx);
2807 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2808 if (group_sched_in(event, cpuctx, ctx))
2815 ctx_sched_in(struct perf_event_context *ctx,
2816 struct perf_cpu_context *cpuctx,
2817 enum event_type_t event_type,
2818 struct task_struct *task)
2821 int is_active = ctx->is_active;
2823 ctx->is_active |= event_type;
2824 if (likely(!ctx->nr_events))
2828 ctx->timestamp = now;
2829 perf_cgroup_set_timestamp(task, ctx);
2831 * First go through the list and put on any pinned groups
2832 * in order to give them the best chance of going on.
2834 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2835 ctx_pinned_sched_in(ctx, cpuctx);
2837 /* Then walk through the lower prio flexible groups */
2838 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2839 ctx_flexible_sched_in(ctx, cpuctx);
2842 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2843 enum event_type_t event_type,
2844 struct task_struct *task)
2846 struct perf_event_context *ctx = &cpuctx->ctx;
2848 ctx_sched_in(ctx, cpuctx, event_type, task);
2851 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2852 struct task_struct *task)
2854 struct perf_cpu_context *cpuctx;
2856 cpuctx = __get_cpu_context(ctx);
2857 if (cpuctx->task_ctx == ctx)
2860 perf_ctx_lock(cpuctx, ctx);
2861 perf_pmu_disable(ctx->pmu);
2863 * We want to keep the following priority order:
2864 * cpu pinned (that don't need to move), task pinned,
2865 * cpu flexible, task flexible.
2867 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2870 cpuctx->task_ctx = ctx;
2872 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2874 perf_pmu_enable(ctx->pmu);
2875 perf_ctx_unlock(cpuctx, ctx);
2879 * Called from scheduler to add the events of the current task
2880 * with interrupts disabled.
2882 * We restore the event value and then enable it.
2884 * This does not protect us against NMI, but enable()
2885 * sets the enabled bit in the control field of event _before_
2886 * accessing the event control register. If a NMI hits, then it will
2887 * keep the event running.
2889 void __perf_event_task_sched_in(struct task_struct *prev,
2890 struct task_struct *task)
2892 struct perf_event_context *ctx;
2895 for_each_task_context_nr(ctxn) {
2896 ctx = task->perf_event_ctxp[ctxn];
2900 perf_event_context_sched_in(ctx, task);
2903 * if cgroup events exist on this CPU, then we need
2904 * to check if we have to switch in PMU state.
2905 * cgroup event are system-wide mode only
2907 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2908 perf_cgroup_sched_in(prev, task);
2910 if (atomic_read(&nr_switch_events))
2911 perf_event_switch(task, prev, true);
2913 if (__this_cpu_read(perf_sched_cb_usages))
2914 perf_pmu_sched_task(prev, task, true);
2917 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2919 u64 frequency = event->attr.sample_freq;
2920 u64 sec = NSEC_PER_SEC;
2921 u64 divisor, dividend;
2923 int count_fls, nsec_fls, frequency_fls, sec_fls;
2925 count_fls = fls64(count);
2926 nsec_fls = fls64(nsec);
2927 frequency_fls = fls64(frequency);
2931 * We got @count in @nsec, with a target of sample_freq HZ
2932 * the target period becomes:
2935 * period = -------------------
2936 * @nsec * sample_freq
2941 * Reduce accuracy by one bit such that @a and @b converge
2942 * to a similar magnitude.
2944 #define REDUCE_FLS(a, b) \
2946 if (a##_fls > b##_fls) { \
2956 * Reduce accuracy until either term fits in a u64, then proceed with
2957 * the other, so that finally we can do a u64/u64 division.
2959 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2960 REDUCE_FLS(nsec, frequency);
2961 REDUCE_FLS(sec, count);
2964 if (count_fls + sec_fls > 64) {
2965 divisor = nsec * frequency;
2967 while (count_fls + sec_fls > 64) {
2968 REDUCE_FLS(count, sec);
2972 dividend = count * sec;
2974 dividend = count * sec;
2976 while (nsec_fls + frequency_fls > 64) {
2977 REDUCE_FLS(nsec, frequency);
2981 divisor = nsec * frequency;
2987 return div64_u64(dividend, divisor);
2990 static DEFINE_PER_CPU(int, perf_throttled_count);
2991 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2993 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2995 struct hw_perf_event *hwc = &event->hw;
2996 s64 period, sample_period;
2999 period = perf_calculate_period(event, nsec, count);
3001 delta = (s64)(period - hwc->sample_period);
3002 delta = (delta + 7) / 8; /* low pass filter */
3004 sample_period = hwc->sample_period + delta;
3009 hwc->sample_period = sample_period;
3011 if (local64_read(&hwc->period_left) > 8*sample_period) {
3013 event->pmu->stop(event, PERF_EF_UPDATE);
3015 local64_set(&hwc->period_left, 0);
3018 event->pmu->start(event, PERF_EF_RELOAD);
3023 * combine freq adjustment with unthrottling to avoid two passes over the
3024 * events. At the same time, make sure, having freq events does not change
3025 * the rate of unthrottling as that would introduce bias.
3027 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3030 struct perf_event *event;
3031 struct hw_perf_event *hwc;
3032 u64 now, period = TICK_NSEC;
3036 * only need to iterate over all events iff:
3037 * - context have events in frequency mode (needs freq adjust)
3038 * - there are events to unthrottle on this cpu
3040 if (!(ctx->nr_freq || needs_unthr))
3043 raw_spin_lock(&ctx->lock);
3044 perf_pmu_disable(ctx->pmu);
3046 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3047 if (event->state != PERF_EVENT_STATE_ACTIVE)
3050 if (!event_filter_match(event))
3053 perf_pmu_disable(event->pmu);
3057 if (hwc->interrupts == MAX_INTERRUPTS) {
3058 hwc->interrupts = 0;
3059 perf_log_throttle(event, 1);
3060 event->pmu->start(event, 0);
3063 if (!event->attr.freq || !event->attr.sample_freq)
3067 * stop the event and update event->count
3069 event->pmu->stop(event, PERF_EF_UPDATE);
3071 now = local64_read(&event->count);
3072 delta = now - hwc->freq_count_stamp;
3073 hwc->freq_count_stamp = now;
3077 * reload only if value has changed
3078 * we have stopped the event so tell that
3079 * to perf_adjust_period() to avoid stopping it
3083 perf_adjust_period(event, period, delta, false);
3085 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3087 perf_pmu_enable(event->pmu);
3090 perf_pmu_enable(ctx->pmu);
3091 raw_spin_unlock(&ctx->lock);
3095 * Round-robin a context's events:
3097 static void rotate_ctx(struct perf_event_context *ctx)
3100 * Rotate the first entry last of non-pinned groups. Rotation might be
3101 * disabled by the inheritance code.
3103 if (!ctx->rotate_disable)
3104 list_rotate_left(&ctx->flexible_groups);
3107 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3109 struct perf_event_context *ctx = NULL;
3112 if (cpuctx->ctx.nr_events) {
3113 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3117 ctx = cpuctx->task_ctx;
3118 if (ctx && ctx->nr_events) {
3119 if (ctx->nr_events != ctx->nr_active)
3126 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3127 perf_pmu_disable(cpuctx->ctx.pmu);
3129 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3131 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3133 rotate_ctx(&cpuctx->ctx);
3137 perf_event_sched_in(cpuctx, ctx, current);
3139 perf_pmu_enable(cpuctx->ctx.pmu);
3140 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3146 #ifdef CONFIG_NO_HZ_FULL
3147 bool perf_event_can_stop_tick(void)
3149 if (atomic_read(&nr_freq_events) ||
3150 __this_cpu_read(perf_throttled_count))
3157 void perf_event_task_tick(void)
3159 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3160 struct perf_event_context *ctx, *tmp;
3163 WARN_ON(!irqs_disabled());
3165 __this_cpu_inc(perf_throttled_seq);
3166 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3168 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3169 perf_adjust_freq_unthr_context(ctx, throttled);
3172 static int event_enable_on_exec(struct perf_event *event,
3173 struct perf_event_context *ctx)
3175 if (!event->attr.enable_on_exec)
3178 event->attr.enable_on_exec = 0;
3179 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3182 __perf_event_mark_enabled(event);
3188 * Enable all of a task's events that have been marked enable-on-exec.
3189 * This expects task == current.
3191 static void perf_event_enable_on_exec(int ctxn)
3193 struct perf_event_context *ctx, *clone_ctx = NULL;
3194 struct perf_event *event;
3195 unsigned long flags;
3199 local_irq_save(flags);
3200 ctx = current->perf_event_ctxp[ctxn];
3201 if (!ctx || !ctx->nr_events)
3205 * We must ctxsw out cgroup events to avoid conflict
3206 * when invoking perf_task_event_sched_in() later on
3207 * in this function. Otherwise we end up trying to
3208 * ctxswin cgroup events which are already scheduled
3211 perf_cgroup_sched_out(current, NULL);
3213 raw_spin_lock(&ctx->lock);
3214 task_ctx_sched_out(ctx);
3216 list_for_each_entry(event, &ctx->event_list, event_entry) {
3217 ret = event_enable_on_exec(event, ctx);
3223 * Unclone this context if we enabled any event.
3226 clone_ctx = unclone_ctx(ctx);
3228 raw_spin_unlock(&ctx->lock);
3231 * Also calls ctxswin for cgroup events, if any:
3233 perf_event_context_sched_in(ctx, ctx->task);
3235 local_irq_restore(flags);
3241 void perf_event_exec(void)
3246 for_each_task_context_nr(ctxn)
3247 perf_event_enable_on_exec(ctxn);
3251 struct perf_read_data {
3252 struct perf_event *event;
3258 * Cross CPU call to read the hardware event
3260 static void __perf_event_read(void *info)
3262 struct perf_read_data *data = info;
3263 struct perf_event *sub, *event = data->event;
3264 struct perf_event_context *ctx = event->ctx;
3265 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3266 struct pmu *pmu = event->pmu;
3269 * If this is a task context, we need to check whether it is
3270 * the current task context of this cpu. If not it has been
3271 * scheduled out before the smp call arrived. In that case
3272 * event->count would have been updated to a recent sample
3273 * when the event was scheduled out.
3275 if (ctx->task && cpuctx->task_ctx != ctx)
3278 raw_spin_lock(&ctx->lock);
3279 if (ctx->is_active) {
3280 update_context_time(ctx);
3281 update_cgrp_time_from_event(event);
3284 update_event_times(event);
3285 if (event->state != PERF_EVENT_STATE_ACTIVE)
3294 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3298 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3299 update_event_times(sub);
3300 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3302 * Use sibling's PMU rather than @event's since
3303 * sibling could be on different (eg: software) PMU.
3305 sub->pmu->read(sub);
3309 data->ret = pmu->commit_txn(pmu);
3312 raw_spin_unlock(&ctx->lock);
3315 static inline u64 perf_event_count(struct perf_event *event)
3317 if (event->pmu->count)
3318 return event->pmu->count(event);
3320 return __perf_event_count(event);
3324 * NMI-safe method to read a local event, that is an event that
3326 * - either for the current task, or for this CPU
3327 * - does not have inherit set, for inherited task events
3328 * will not be local and we cannot read them atomically
3329 * - must not have a pmu::count method
3331 u64 perf_event_read_local(struct perf_event *event)
3333 unsigned long flags;
3337 * Disabling interrupts avoids all counter scheduling (context
3338 * switches, timer based rotation and IPIs).
3340 local_irq_save(flags);
3342 /* If this is a per-task event, it must be for current */
3343 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3344 event->hw.target != current);
3346 /* If this is a per-CPU event, it must be for this CPU */
3347 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3348 event->cpu != smp_processor_id());
3351 * It must not be an event with inherit set, we cannot read
3352 * all child counters from atomic context.
3354 WARN_ON_ONCE(event->attr.inherit);
3357 * It must not have a pmu::count method, those are not
3360 WARN_ON_ONCE(event->pmu->count);
3363 * If the event is currently on this CPU, its either a per-task event,
3364 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3367 if (event->oncpu == smp_processor_id())
3368 event->pmu->read(event);
3370 val = local64_read(&event->count);
3371 local_irq_restore(flags);
3376 static int perf_event_read(struct perf_event *event, bool group)
3381 * If event is enabled and currently active on a CPU, update the
3382 * value in the event structure:
3384 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3385 struct perf_read_data data = {
3390 smp_call_function_single(event->oncpu,
3391 __perf_event_read, &data, 1);
3393 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3394 struct perf_event_context *ctx = event->ctx;
3395 unsigned long flags;
3397 raw_spin_lock_irqsave(&ctx->lock, flags);
3399 * may read while context is not active
3400 * (e.g., thread is blocked), in that case
3401 * we cannot update context time
3403 if (ctx->is_active) {
3404 update_context_time(ctx);
3405 update_cgrp_time_from_event(event);
3408 update_group_times(event);
3410 update_event_times(event);
3411 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3418 * Initialize the perf_event context in a task_struct:
3420 static void __perf_event_init_context(struct perf_event_context *ctx)
3422 raw_spin_lock_init(&ctx->lock);
3423 mutex_init(&ctx->mutex);
3424 INIT_LIST_HEAD(&ctx->active_ctx_list);
3425 INIT_LIST_HEAD(&ctx->pinned_groups);
3426 INIT_LIST_HEAD(&ctx->flexible_groups);
3427 INIT_LIST_HEAD(&ctx->event_list);
3428 atomic_set(&ctx->refcount, 1);
3429 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3432 static struct perf_event_context *
3433 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3435 struct perf_event_context *ctx;
3437 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3441 __perf_event_init_context(ctx);
3444 get_task_struct(task);
3451 static struct task_struct *
3452 find_lively_task_by_vpid(pid_t vpid)
3454 struct task_struct *task;
3460 task = find_task_by_vpid(vpid);
3462 get_task_struct(task);
3466 return ERR_PTR(-ESRCH);
3472 * Returns a matching context with refcount and pincount.
3474 static struct perf_event_context *
3475 find_get_context(struct pmu *pmu, struct task_struct *task,
3476 struct perf_event *event)
3478 struct perf_event_context *ctx, *clone_ctx = NULL;
3479 struct perf_cpu_context *cpuctx;
3480 void *task_ctx_data = NULL;
3481 unsigned long flags;
3483 int cpu = event->cpu;
3486 /* Must be root to operate on a CPU event: */
3487 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3488 return ERR_PTR(-EACCES);
3491 * We could be clever and allow to attach a event to an
3492 * offline CPU and activate it when the CPU comes up, but
3495 if (!cpu_online(cpu))
3496 return ERR_PTR(-ENODEV);
3498 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3507 ctxn = pmu->task_ctx_nr;
3511 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3512 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3513 if (!task_ctx_data) {
3520 ctx = perf_lock_task_context(task, ctxn, &flags);
3522 clone_ctx = unclone_ctx(ctx);
3525 if (task_ctx_data && !ctx->task_ctx_data) {
3526 ctx->task_ctx_data = task_ctx_data;
3527 task_ctx_data = NULL;
3529 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3534 ctx = alloc_perf_context(pmu, task);
3539 if (task_ctx_data) {
3540 ctx->task_ctx_data = task_ctx_data;
3541 task_ctx_data = NULL;
3545 mutex_lock(&task->perf_event_mutex);
3547 * If it has already passed perf_event_exit_task().
3548 * we must see PF_EXITING, it takes this mutex too.
3550 if (task->flags & PF_EXITING)
3552 else if (task->perf_event_ctxp[ctxn])
3557 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3559 mutex_unlock(&task->perf_event_mutex);
3561 if (unlikely(err)) {
3570 kfree(task_ctx_data);
3574 kfree(task_ctx_data);
3575 return ERR_PTR(err);
3578 static void perf_event_free_filter(struct perf_event *event);
3579 static void perf_event_free_bpf_prog(struct perf_event *event);
3581 static void free_event_rcu(struct rcu_head *head)
3583 struct perf_event *event;
3585 event = container_of(head, struct perf_event, rcu_head);
3587 put_pid_ns(event->ns);
3588 perf_event_free_filter(event);
3592 static void ring_buffer_attach(struct perf_event *event,
3593 struct ring_buffer *rb);
3595 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3600 if (is_cgroup_event(event))
3601 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3604 static void unaccount_event(struct perf_event *event)
3609 if (event->attach_state & PERF_ATTACH_TASK)
3610 static_key_slow_dec_deferred(&perf_sched_events);
3611 if (event->attr.mmap || event->attr.mmap_data)
3612 atomic_dec(&nr_mmap_events);
3613 if (event->attr.comm)
3614 atomic_dec(&nr_comm_events);
3615 if (event->attr.task)
3616 atomic_dec(&nr_task_events);
3617 if (event->attr.freq)
3618 atomic_dec(&nr_freq_events);
3619 if (event->attr.context_switch) {
3620 static_key_slow_dec_deferred(&perf_sched_events);
3621 atomic_dec(&nr_switch_events);
3623 if (is_cgroup_event(event))
3624 static_key_slow_dec_deferred(&perf_sched_events);
3625 if (has_branch_stack(event))
3626 static_key_slow_dec_deferred(&perf_sched_events);
3628 unaccount_event_cpu(event, event->cpu);
3632 * The following implement mutual exclusion of events on "exclusive" pmus
3633 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3634 * at a time, so we disallow creating events that might conflict, namely:
3636 * 1) cpu-wide events in the presence of per-task events,
3637 * 2) per-task events in the presence of cpu-wide events,
3638 * 3) two matching events on the same context.
3640 * The former two cases are handled in the allocation path (perf_event_alloc(),
3641 * __free_event()), the latter -- before the first perf_install_in_context().
3643 static int exclusive_event_init(struct perf_event *event)
3645 struct pmu *pmu = event->pmu;
3647 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3651 * Prevent co-existence of per-task and cpu-wide events on the
3652 * same exclusive pmu.
3654 * Negative pmu::exclusive_cnt means there are cpu-wide
3655 * events on this "exclusive" pmu, positive means there are
3658 * Since this is called in perf_event_alloc() path, event::ctx
3659 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3660 * to mean "per-task event", because unlike other attach states it
3661 * never gets cleared.
3663 if (event->attach_state & PERF_ATTACH_TASK) {
3664 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3667 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3674 static void exclusive_event_destroy(struct perf_event *event)
3676 struct pmu *pmu = event->pmu;
3678 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3681 /* see comment in exclusive_event_init() */
3682 if (event->attach_state & PERF_ATTACH_TASK)
3683 atomic_dec(&pmu->exclusive_cnt);
3685 atomic_inc(&pmu->exclusive_cnt);
3688 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3690 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3691 (e1->cpu == e2->cpu ||
3698 /* Called under the same ctx::mutex as perf_install_in_context() */
3699 static bool exclusive_event_installable(struct perf_event *event,
3700 struct perf_event_context *ctx)
3702 struct perf_event *iter_event;
3703 struct pmu *pmu = event->pmu;
3705 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3708 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3709 if (exclusive_event_match(iter_event, event))
3716 static void __free_event(struct perf_event *event)
3718 if (!event->parent) {
3719 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3720 put_callchain_buffers();
3723 perf_event_free_bpf_prog(event);
3726 event->destroy(event);
3728 if (event->pmu->free_drv_configs)
3729 event->pmu->free_drv_configs(event);
3732 put_ctx(event->ctx);
3735 exclusive_event_destroy(event);
3736 module_put(event->pmu->module);
3739 call_rcu(&event->rcu_head, free_event_rcu);
3742 static void _free_event(struct perf_event *event)
3744 irq_work_sync(&event->pending);
3746 unaccount_event(event);
3750 * Can happen when we close an event with re-directed output.
3752 * Since we have a 0 refcount, perf_mmap_close() will skip
3753 * over us; possibly making our ring_buffer_put() the last.
3755 mutex_lock(&event->mmap_mutex);
3756 ring_buffer_attach(event, NULL);
3757 mutex_unlock(&event->mmap_mutex);
3760 if (is_cgroup_event(event))
3761 perf_detach_cgroup(event);
3763 __free_event(event);
3767 * Used to free events which have a known refcount of 1, such as in error paths
3768 * where the event isn't exposed yet and inherited events.
3770 static void free_event(struct perf_event *event)
3772 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3773 "unexpected event refcount: %ld; ptr=%p\n",
3774 atomic_long_read(&event->refcount), event)) {
3775 /* leak to avoid use-after-free */
3783 * Remove user event from the owner task.
3785 static void perf_remove_from_owner(struct perf_event *event)
3787 struct task_struct *owner;
3790 owner = ACCESS_ONCE(event->owner);
3792 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3793 * !owner it means the list deletion is complete and we can indeed
3794 * free this event, otherwise we need to serialize on
3795 * owner->perf_event_mutex.
3797 smp_read_barrier_depends();
3800 * Since delayed_put_task_struct() also drops the last
3801 * task reference we can safely take a new reference
3802 * while holding the rcu_read_lock().
3804 get_task_struct(owner);
3810 * If we're here through perf_event_exit_task() we're already
3811 * holding ctx->mutex which would be an inversion wrt. the
3812 * normal lock order.
3814 * However we can safely take this lock because its the child
3817 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3820 * We have to re-check the event->owner field, if it is cleared
3821 * we raced with perf_event_exit_task(), acquiring the mutex
3822 * ensured they're done, and we can proceed with freeing the
3826 list_del_init(&event->owner_entry);
3827 mutex_unlock(&owner->perf_event_mutex);
3828 put_task_struct(owner);
3832 static void put_event(struct perf_event *event)
3834 struct perf_event_context *ctx;
3836 if (!atomic_long_dec_and_test(&event->refcount))
3839 if (!is_kernel_event(event))
3840 perf_remove_from_owner(event);
3843 * There are two ways this annotation is useful:
3845 * 1) there is a lock recursion from perf_event_exit_task
3846 * see the comment there.
3848 * 2) there is a lock-inversion with mmap_sem through
3849 * perf_read_group(), which takes faults while
3850 * holding ctx->mutex, however this is called after
3851 * the last filedesc died, so there is no possibility
3852 * to trigger the AB-BA case.
3854 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3855 WARN_ON_ONCE(ctx->parent_ctx);
3856 perf_remove_from_context(event, true);
3857 perf_event_ctx_unlock(event, ctx);
3862 int perf_event_release_kernel(struct perf_event *event)
3867 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3870 * Called when the last reference to the file is gone.
3872 static int perf_release(struct inode *inode, struct file *file)
3874 put_event(file->private_data);
3879 * Remove all orphanes events from the context.
3881 static void orphans_remove_work(struct work_struct *work)
3883 struct perf_event_context *ctx;
3884 struct perf_event *event, *tmp;
3886 ctx = container_of(work, struct perf_event_context,
3887 orphans_remove.work);
3889 mutex_lock(&ctx->mutex);
3890 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3891 struct perf_event *parent_event = event->parent;
3893 if (!is_orphaned_child(event))
3896 perf_remove_from_context(event, true);
3898 mutex_lock(&parent_event->child_mutex);
3899 list_del_init(&event->child_list);
3900 mutex_unlock(&parent_event->child_mutex);
3903 put_event(parent_event);
3906 raw_spin_lock_irq(&ctx->lock);
3907 ctx->orphans_remove_sched = false;
3908 raw_spin_unlock_irq(&ctx->lock);
3909 mutex_unlock(&ctx->mutex);
3914 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3916 struct perf_event *child;
3922 mutex_lock(&event->child_mutex);
3924 (void)perf_event_read(event, false);
3925 total += perf_event_count(event);
3927 *enabled += event->total_time_enabled +
3928 atomic64_read(&event->child_total_time_enabled);
3929 *running += event->total_time_running +
3930 atomic64_read(&event->child_total_time_running);
3932 list_for_each_entry(child, &event->child_list, child_list) {
3933 (void)perf_event_read(child, false);
3934 total += perf_event_count(child);
3935 *enabled += child->total_time_enabled;
3936 *running += child->total_time_running;
3938 mutex_unlock(&event->child_mutex);
3942 EXPORT_SYMBOL_GPL(perf_event_read_value);
3944 static int __perf_read_group_add(struct perf_event *leader,
3945 u64 read_format, u64 *values)
3947 struct perf_event *sub;
3948 int n = 1; /* skip @nr */
3951 ret = perf_event_read(leader, true);
3956 * Since we co-schedule groups, {enabled,running} times of siblings
3957 * will be identical to those of the leader, so we only publish one
3960 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3961 values[n++] += leader->total_time_enabled +
3962 atomic64_read(&leader->child_total_time_enabled);
3965 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3966 values[n++] += leader->total_time_running +
3967 atomic64_read(&leader->child_total_time_running);
3971 * Write {count,id} tuples for every sibling.
3973 values[n++] += perf_event_count(leader);
3974 if (read_format & PERF_FORMAT_ID)
3975 values[n++] = primary_event_id(leader);
3977 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3978 values[n++] += perf_event_count(sub);
3979 if (read_format & PERF_FORMAT_ID)
3980 values[n++] = primary_event_id(sub);
3986 static int perf_read_group(struct perf_event *event,
3987 u64 read_format, char __user *buf)
3989 struct perf_event *leader = event->group_leader, *child;
3990 struct perf_event_context *ctx = leader->ctx;
3994 lockdep_assert_held(&ctx->mutex);
3996 values = kzalloc(event->read_size, GFP_KERNEL);
4000 values[0] = 1 + leader->nr_siblings;
4003 * By locking the child_mutex of the leader we effectively
4004 * lock the child list of all siblings.. XXX explain how.
4006 mutex_lock(&leader->child_mutex);
4008 ret = __perf_read_group_add(leader, read_format, values);
4012 list_for_each_entry(child, &leader->child_list, child_list) {
4013 ret = __perf_read_group_add(child, read_format, values);
4018 mutex_unlock(&leader->child_mutex);
4020 ret = event->read_size;
4021 if (copy_to_user(buf, values, event->read_size))
4026 mutex_unlock(&leader->child_mutex);
4032 static int perf_read_one(struct perf_event *event,
4033 u64 read_format, char __user *buf)
4035 u64 enabled, running;
4039 values[n++] = perf_event_read_value(event, &enabled, &running);
4040 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4041 values[n++] = enabled;
4042 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4043 values[n++] = running;
4044 if (read_format & PERF_FORMAT_ID)
4045 values[n++] = primary_event_id(event);
4047 if (copy_to_user(buf, values, n * sizeof(u64)))
4050 return n * sizeof(u64);
4053 static bool is_event_hup(struct perf_event *event)
4057 if (event->state != PERF_EVENT_STATE_EXIT)
4060 mutex_lock(&event->child_mutex);
4061 no_children = list_empty(&event->child_list);
4062 mutex_unlock(&event->child_mutex);
4067 * Read the performance event - simple non blocking version for now
4070 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4072 u64 read_format = event->attr.read_format;
4076 * Return end-of-file for a read on a event that is in
4077 * error state (i.e. because it was pinned but it couldn't be
4078 * scheduled on to the CPU at some point).
4080 if (event->state == PERF_EVENT_STATE_ERROR)
4083 if (count < event->read_size)
4086 WARN_ON_ONCE(event->ctx->parent_ctx);
4087 if (read_format & PERF_FORMAT_GROUP)
4088 ret = perf_read_group(event, read_format, buf);
4090 ret = perf_read_one(event, read_format, buf);
4096 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4098 struct perf_event *event = file->private_data;
4099 struct perf_event_context *ctx;
4102 ctx = perf_event_ctx_lock(event);
4103 ret = __perf_read(event, buf, count);
4104 perf_event_ctx_unlock(event, ctx);
4109 static unsigned int perf_poll(struct file *file, poll_table *wait)
4111 struct perf_event *event = file->private_data;
4112 struct ring_buffer *rb;
4113 unsigned int events = POLLHUP;
4115 poll_wait(file, &event->waitq, wait);
4117 if (is_event_hup(event))
4121 * Pin the event->rb by taking event->mmap_mutex; otherwise
4122 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4124 mutex_lock(&event->mmap_mutex);
4127 events = atomic_xchg(&rb->poll, 0);
4128 mutex_unlock(&event->mmap_mutex);
4132 static void _perf_event_reset(struct perf_event *event)
4134 (void)perf_event_read(event, false);
4135 local64_set(&event->count, 0);
4136 perf_event_update_userpage(event);
4140 * Holding the top-level event's child_mutex means that any
4141 * descendant process that has inherited this event will block
4142 * in sync_child_event if it goes to exit, thus satisfying the
4143 * task existence requirements of perf_event_enable/disable.
4145 static void perf_event_for_each_child(struct perf_event *event,
4146 void (*func)(struct perf_event *))
4148 struct perf_event *child;
4150 WARN_ON_ONCE(event->ctx->parent_ctx);
4152 mutex_lock(&event->child_mutex);
4154 list_for_each_entry(child, &event->child_list, child_list)
4156 mutex_unlock(&event->child_mutex);
4159 static void perf_event_for_each(struct perf_event *event,
4160 void (*func)(struct perf_event *))
4162 struct perf_event_context *ctx = event->ctx;
4163 struct perf_event *sibling;
4165 lockdep_assert_held(&ctx->mutex);
4167 event = event->group_leader;
4169 perf_event_for_each_child(event, func);
4170 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4171 perf_event_for_each_child(sibling, func);
4174 struct period_event {
4175 struct perf_event *event;
4179 static int __perf_event_period(void *info)
4181 struct period_event *pe = info;
4182 struct perf_event *event = pe->event;
4183 struct perf_event_context *ctx = event->ctx;
4184 u64 value = pe->value;
4187 raw_spin_lock(&ctx->lock);
4188 if (event->attr.freq) {
4189 event->attr.sample_freq = value;
4191 event->attr.sample_period = value;
4192 event->hw.sample_period = value;
4195 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4197 perf_pmu_disable(ctx->pmu);
4198 event->pmu->stop(event, PERF_EF_UPDATE);
4201 local64_set(&event->hw.period_left, 0);
4204 event->pmu->start(event, PERF_EF_RELOAD);
4205 perf_pmu_enable(ctx->pmu);
4207 raw_spin_unlock(&ctx->lock);
4212 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4214 struct period_event pe = { .event = event, };
4215 struct perf_event_context *ctx = event->ctx;
4216 struct task_struct *task;
4219 if (!is_sampling_event(event))
4222 if (copy_from_user(&value, arg, sizeof(value)))
4228 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4235 cpu_function_call(event->cpu, __perf_event_period, &pe);
4240 if (!task_function_call(task, __perf_event_period, &pe))
4243 raw_spin_lock_irq(&ctx->lock);
4244 if (ctx->is_active) {
4245 raw_spin_unlock_irq(&ctx->lock);
4250 if (event->attr.freq) {
4251 event->attr.sample_freq = value;
4253 event->attr.sample_period = value;
4254 event->hw.sample_period = value;
4257 local64_set(&event->hw.period_left, 0);
4258 raw_spin_unlock_irq(&ctx->lock);
4263 static const struct file_operations perf_fops;
4265 static inline int perf_fget_light(int fd, struct fd *p)
4267 struct fd f = fdget(fd);
4271 if (f.file->f_op != &perf_fops) {
4279 static int perf_event_set_output(struct perf_event *event,
4280 struct perf_event *output_event);
4281 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4282 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4283 static int perf_event_drv_configs(struct perf_event *event,
4286 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4288 void (*func)(struct perf_event *);
4292 case PERF_EVENT_IOC_ENABLE:
4293 func = _perf_event_enable;
4295 case PERF_EVENT_IOC_DISABLE:
4296 func = _perf_event_disable;
4298 case PERF_EVENT_IOC_RESET:
4299 func = _perf_event_reset;
4302 case PERF_EVENT_IOC_REFRESH:
4303 return _perf_event_refresh(event, arg);
4305 case PERF_EVENT_IOC_PERIOD:
4306 return perf_event_period(event, (u64 __user *)arg);
4308 case PERF_EVENT_IOC_ID:
4310 u64 id = primary_event_id(event);
4312 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4317 case PERF_EVENT_IOC_SET_OUTPUT:
4321 struct perf_event *output_event;
4323 ret = perf_fget_light(arg, &output);
4326 output_event = output.file->private_data;
4327 ret = perf_event_set_output(event, output_event);
4330 ret = perf_event_set_output(event, NULL);
4335 case PERF_EVENT_IOC_SET_FILTER:
4336 return perf_event_set_filter(event, (void __user *)arg);
4338 case PERF_EVENT_IOC_SET_BPF:
4339 return perf_event_set_bpf_prog(event, arg);
4341 case PERF_EVENT_IOC_SET_DRV_CONFIGS:
4342 return perf_event_drv_configs(event, (void __user *)arg);
4348 if (flags & PERF_IOC_FLAG_GROUP)
4349 perf_event_for_each(event, func);
4351 perf_event_for_each_child(event, func);
4356 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4358 struct perf_event *event = file->private_data;
4359 struct perf_event_context *ctx;
4362 ctx = perf_event_ctx_lock(event);
4363 ret = _perf_ioctl(event, cmd, arg);
4364 perf_event_ctx_unlock(event, ctx);
4369 #ifdef CONFIG_COMPAT
4370 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4373 switch (_IOC_NR(cmd)) {
4374 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4375 case _IOC_NR(PERF_EVENT_IOC_ID):
4376 case _IOC_NR(PERF_EVENT_IOC_SET_DRV_CONFIGS):
4377 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4378 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4379 cmd &= ~IOCSIZE_MASK;
4380 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4384 return perf_ioctl(file, cmd, arg);
4387 # define perf_compat_ioctl NULL
4390 int perf_event_task_enable(void)
4392 struct perf_event_context *ctx;
4393 struct perf_event *event;
4395 mutex_lock(¤t->perf_event_mutex);
4396 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4397 ctx = perf_event_ctx_lock(event);
4398 perf_event_for_each_child(event, _perf_event_enable);
4399 perf_event_ctx_unlock(event, ctx);
4401 mutex_unlock(¤t->perf_event_mutex);
4406 int perf_event_task_disable(void)
4408 struct perf_event_context *ctx;
4409 struct perf_event *event;
4411 mutex_lock(¤t->perf_event_mutex);
4412 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4413 ctx = perf_event_ctx_lock(event);
4414 perf_event_for_each_child(event, _perf_event_disable);
4415 perf_event_ctx_unlock(event, ctx);
4417 mutex_unlock(¤t->perf_event_mutex);
4422 static int perf_event_index(struct perf_event *event)
4424 if (event->hw.state & PERF_HES_STOPPED)
4427 if (event->state != PERF_EVENT_STATE_ACTIVE)
4430 return event->pmu->event_idx(event);
4433 static void calc_timer_values(struct perf_event *event,
4440 *now = perf_clock();
4441 ctx_time = event->shadow_ctx_time + *now;
4442 *enabled = ctx_time - event->tstamp_enabled;
4443 *running = ctx_time - event->tstamp_running;
4446 static void perf_event_init_userpage(struct perf_event *event)
4448 struct perf_event_mmap_page *userpg;
4449 struct ring_buffer *rb;
4452 rb = rcu_dereference(event->rb);
4456 userpg = rb->user_page;
4458 /* Allow new userspace to detect that bit 0 is deprecated */
4459 userpg->cap_bit0_is_deprecated = 1;
4460 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4461 userpg->data_offset = PAGE_SIZE;
4462 userpg->data_size = perf_data_size(rb);
4468 void __weak arch_perf_update_userpage(
4469 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4474 * Callers need to ensure there can be no nesting of this function, otherwise
4475 * the seqlock logic goes bad. We can not serialize this because the arch
4476 * code calls this from NMI context.
4478 void perf_event_update_userpage(struct perf_event *event)
4480 struct perf_event_mmap_page *userpg;
4481 struct ring_buffer *rb;
4482 u64 enabled, running, now;
4485 rb = rcu_dereference(event->rb);
4490 * compute total_time_enabled, total_time_running
4491 * based on snapshot values taken when the event
4492 * was last scheduled in.
4494 * we cannot simply called update_context_time()
4495 * because of locking issue as we can be called in
4498 calc_timer_values(event, &now, &enabled, &running);
4500 userpg = rb->user_page;
4502 * Disable preemption so as to not let the corresponding user-space
4503 * spin too long if we get preempted.
4508 userpg->index = perf_event_index(event);
4509 userpg->offset = perf_event_count(event);
4511 userpg->offset -= local64_read(&event->hw.prev_count);
4513 userpg->time_enabled = enabled +
4514 atomic64_read(&event->child_total_time_enabled);
4516 userpg->time_running = running +
4517 atomic64_read(&event->child_total_time_running);
4519 arch_perf_update_userpage(event, userpg, now);
4528 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4530 struct perf_event *event = vma->vm_file->private_data;
4531 struct ring_buffer *rb;
4532 int ret = VM_FAULT_SIGBUS;
4534 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4535 if (vmf->pgoff == 0)
4541 rb = rcu_dereference(event->rb);
4545 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4548 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4552 get_page(vmf->page);
4553 vmf->page->mapping = vma->vm_file->f_mapping;
4554 vmf->page->index = vmf->pgoff;
4563 static void ring_buffer_attach(struct perf_event *event,
4564 struct ring_buffer *rb)
4566 struct ring_buffer *old_rb = NULL;
4567 unsigned long flags;
4571 * Should be impossible, we set this when removing
4572 * event->rb_entry and wait/clear when adding event->rb_entry.
4574 WARN_ON_ONCE(event->rcu_pending);
4577 spin_lock_irqsave(&old_rb->event_lock, flags);
4578 list_del_rcu(&event->rb_entry);
4579 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4581 event->rcu_batches = get_state_synchronize_rcu();
4582 event->rcu_pending = 1;
4586 if (event->rcu_pending) {
4587 cond_synchronize_rcu(event->rcu_batches);
4588 event->rcu_pending = 0;
4591 spin_lock_irqsave(&rb->event_lock, flags);
4592 list_add_rcu(&event->rb_entry, &rb->event_list);
4593 spin_unlock_irqrestore(&rb->event_lock, flags);
4596 rcu_assign_pointer(event->rb, rb);
4599 ring_buffer_put(old_rb);
4601 * Since we detached before setting the new rb, so that we
4602 * could attach the new rb, we could have missed a wakeup.
4605 wake_up_all(&event->waitq);
4609 static void ring_buffer_wakeup(struct perf_event *event)
4611 struct ring_buffer *rb;
4614 rb = rcu_dereference(event->rb);
4616 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4617 wake_up_all(&event->waitq);
4622 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4624 struct ring_buffer *rb;
4627 rb = rcu_dereference(event->rb);
4629 if (!atomic_inc_not_zero(&rb->refcount))
4637 void ring_buffer_put(struct ring_buffer *rb)
4639 if (!atomic_dec_and_test(&rb->refcount))
4642 WARN_ON_ONCE(!list_empty(&rb->event_list));
4644 call_rcu(&rb->rcu_head, rb_free_rcu);
4647 static void perf_mmap_open(struct vm_area_struct *vma)
4649 struct perf_event *event = vma->vm_file->private_data;
4651 atomic_inc(&event->mmap_count);
4652 atomic_inc(&event->rb->mmap_count);
4655 atomic_inc(&event->rb->aux_mmap_count);
4657 if (event->pmu->event_mapped)
4658 event->pmu->event_mapped(event);
4661 static void perf_pmu_output_stop(struct perf_event *event);
4664 * A buffer can be mmap()ed multiple times; either directly through the same
4665 * event, or through other events by use of perf_event_set_output().
4667 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4668 * the buffer here, where we still have a VM context. This means we need
4669 * to detach all events redirecting to us.
4671 static void perf_mmap_close(struct vm_area_struct *vma)
4673 struct perf_event *event = vma->vm_file->private_data;
4675 struct ring_buffer *rb = ring_buffer_get(event);
4676 struct user_struct *mmap_user = rb->mmap_user;
4677 int mmap_locked = rb->mmap_locked;
4678 unsigned long size = perf_data_size(rb);
4680 if (event->pmu->event_unmapped)
4681 event->pmu->event_unmapped(event);
4684 * rb->aux_mmap_count will always drop before rb->mmap_count and
4685 * event->mmap_count, so it is ok to use event->mmap_mutex to
4686 * serialize with perf_mmap here.
4688 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4689 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4691 * Stop all AUX events that are writing to this buffer,
4692 * so that we can free its AUX pages and corresponding PMU
4693 * data. Note that after rb::aux_mmap_count dropped to zero,
4694 * they won't start any more (see perf_aux_output_begin()).
4696 perf_pmu_output_stop(event);
4698 /* now it's safe to free the pages */
4699 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4700 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4702 /* this has to be the last one */
4704 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4706 mutex_unlock(&event->mmap_mutex);
4709 atomic_dec(&rb->mmap_count);
4711 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4714 ring_buffer_attach(event, NULL);
4715 mutex_unlock(&event->mmap_mutex);
4717 /* If there's still other mmap()s of this buffer, we're done. */
4718 if (atomic_read(&rb->mmap_count))
4722 * No other mmap()s, detach from all other events that might redirect
4723 * into the now unreachable buffer. Somewhat complicated by the
4724 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4728 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4729 if (!atomic_long_inc_not_zero(&event->refcount)) {
4731 * This event is en-route to free_event() which will
4732 * detach it and remove it from the list.
4738 mutex_lock(&event->mmap_mutex);
4740 * Check we didn't race with perf_event_set_output() which can
4741 * swizzle the rb from under us while we were waiting to
4742 * acquire mmap_mutex.
4744 * If we find a different rb; ignore this event, a next
4745 * iteration will no longer find it on the list. We have to
4746 * still restart the iteration to make sure we're not now
4747 * iterating the wrong list.
4749 if (event->rb == rb)
4750 ring_buffer_attach(event, NULL);
4752 mutex_unlock(&event->mmap_mutex);
4756 * Restart the iteration; either we're on the wrong list or
4757 * destroyed its integrity by doing a deletion.
4764 * It could be there's still a few 0-ref events on the list; they'll
4765 * get cleaned up by free_event() -- they'll also still have their
4766 * ref on the rb and will free it whenever they are done with it.
4768 * Aside from that, this buffer is 'fully' detached and unmapped,
4769 * undo the VM accounting.
4772 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4773 vma->vm_mm->pinned_vm -= mmap_locked;
4774 free_uid(mmap_user);
4777 ring_buffer_put(rb); /* could be last */
4780 static const struct vm_operations_struct perf_mmap_vmops = {
4781 .open = perf_mmap_open,
4782 .close = perf_mmap_close, /* non mergable */
4783 .fault = perf_mmap_fault,
4784 .page_mkwrite = perf_mmap_fault,
4787 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4789 struct perf_event *event = file->private_data;
4790 unsigned long user_locked, user_lock_limit;
4791 struct user_struct *user = current_user();
4792 unsigned long locked, lock_limit;
4793 struct ring_buffer *rb = NULL;
4794 unsigned long vma_size;
4795 unsigned long nr_pages;
4796 long user_extra = 0, extra = 0;
4797 int ret = 0, flags = 0;
4800 * Don't allow mmap() of inherited per-task counters. This would
4801 * create a performance issue due to all children writing to the
4804 if (event->cpu == -1 && event->attr.inherit)
4807 if (!(vma->vm_flags & VM_SHARED))
4810 vma_size = vma->vm_end - vma->vm_start;
4812 if (vma->vm_pgoff == 0) {
4813 nr_pages = (vma_size / PAGE_SIZE) - 1;
4816 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4817 * mapped, all subsequent mappings should have the same size
4818 * and offset. Must be above the normal perf buffer.
4820 u64 aux_offset, aux_size;
4825 nr_pages = vma_size / PAGE_SIZE;
4827 mutex_lock(&event->mmap_mutex);
4834 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4835 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4837 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4840 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4843 /* already mapped with a different offset */
4844 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4847 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4850 /* already mapped with a different size */
4851 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4854 if (!is_power_of_2(nr_pages))
4857 if (!atomic_inc_not_zero(&rb->mmap_count))
4860 if (rb_has_aux(rb)) {
4861 atomic_inc(&rb->aux_mmap_count);
4866 atomic_set(&rb->aux_mmap_count, 1);
4867 user_extra = nr_pages;
4873 * If we have rb pages ensure they're a power-of-two number, so we
4874 * can do bitmasks instead of modulo.
4876 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4879 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4882 WARN_ON_ONCE(event->ctx->parent_ctx);
4884 mutex_lock(&event->mmap_mutex);
4886 if (event->rb->nr_pages != nr_pages) {
4891 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4893 * Raced against perf_mmap_close() through
4894 * perf_event_set_output(). Try again, hope for better
4897 mutex_unlock(&event->mmap_mutex);
4904 user_extra = nr_pages + 1;
4907 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4910 * Increase the limit linearly with more CPUs:
4912 user_lock_limit *= num_online_cpus();
4914 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4916 if (user_locked > user_lock_limit)
4917 extra = user_locked - user_lock_limit;
4919 lock_limit = rlimit(RLIMIT_MEMLOCK);
4920 lock_limit >>= PAGE_SHIFT;
4921 locked = vma->vm_mm->pinned_vm + extra;
4923 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4924 !capable(CAP_IPC_LOCK)) {
4929 WARN_ON(!rb && event->rb);
4931 if (vma->vm_flags & VM_WRITE)
4932 flags |= RING_BUFFER_WRITABLE;
4935 rb = rb_alloc(nr_pages,
4936 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4944 atomic_set(&rb->mmap_count, 1);
4945 rb->mmap_user = get_current_user();
4946 rb->mmap_locked = extra;
4948 ring_buffer_attach(event, rb);
4950 perf_event_init_userpage(event);
4951 perf_event_update_userpage(event);
4953 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4954 event->attr.aux_watermark, flags);
4956 rb->aux_mmap_locked = extra;
4961 atomic_long_add(user_extra, &user->locked_vm);
4962 vma->vm_mm->pinned_vm += extra;
4964 atomic_inc(&event->mmap_count);
4966 atomic_dec(&rb->mmap_count);
4969 mutex_unlock(&event->mmap_mutex);
4972 * Since pinned accounting is per vm we cannot allow fork() to copy our
4975 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4976 vma->vm_ops = &perf_mmap_vmops;
4978 if (event->pmu->event_mapped)
4979 event->pmu->event_mapped(event);
4984 static int perf_fasync(int fd, struct file *filp, int on)
4986 struct inode *inode = file_inode(filp);
4987 struct perf_event *event = filp->private_data;
4990 mutex_lock(&inode->i_mutex);
4991 retval = fasync_helper(fd, filp, on, &event->fasync);
4992 mutex_unlock(&inode->i_mutex);
5000 static const struct file_operations perf_fops = {
5001 .llseek = no_llseek,
5002 .release = perf_release,
5005 .unlocked_ioctl = perf_ioctl,
5006 .compat_ioctl = perf_compat_ioctl,
5008 .fasync = perf_fasync,
5014 * If there's data, ensure we set the poll() state and publish everything
5015 * to user-space before waking everybody up.
5018 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5020 /* only the parent has fasync state */
5022 event = event->parent;
5023 return &event->fasync;
5026 void perf_event_wakeup(struct perf_event *event)
5028 ring_buffer_wakeup(event);
5030 if (event->pending_kill) {
5031 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5032 event->pending_kill = 0;
5036 static void perf_pending_event(struct irq_work *entry)
5038 struct perf_event *event = container_of(entry,
5039 struct perf_event, pending);
5042 rctx = perf_swevent_get_recursion_context();
5044 * If we 'fail' here, that's OK, it means recursion is already disabled
5045 * and we won't recurse 'further'.
5048 if (event->pending_disable) {
5049 event->pending_disable = 0;
5050 __perf_event_disable(event);
5053 if (event->pending_wakeup) {
5054 event->pending_wakeup = 0;
5055 perf_event_wakeup(event);
5059 perf_swevent_put_recursion_context(rctx);
5063 * We assume there is only KVM supporting the callbacks.
5064 * Later on, we might change it to a list if there is
5065 * another virtualization implementation supporting the callbacks.
5067 struct perf_guest_info_callbacks *perf_guest_cbs;
5069 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5071 perf_guest_cbs = cbs;
5074 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5076 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5078 perf_guest_cbs = NULL;
5081 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5084 perf_output_sample_regs(struct perf_output_handle *handle,
5085 struct pt_regs *regs, u64 mask)
5089 for_each_set_bit(bit, (const unsigned long *) &mask,
5090 sizeof(mask) * BITS_PER_BYTE) {
5093 val = perf_reg_value(regs, bit);
5094 perf_output_put(handle, val);
5098 static void perf_sample_regs_user(struct perf_regs *regs_user,
5099 struct pt_regs *regs,
5100 struct pt_regs *regs_user_copy)
5102 if (user_mode(regs)) {
5103 regs_user->abi = perf_reg_abi(current);
5104 regs_user->regs = regs;
5105 } else if (current->mm) {
5106 perf_get_regs_user(regs_user, regs, regs_user_copy);
5108 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5109 regs_user->regs = NULL;
5113 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5114 struct pt_regs *regs)
5116 regs_intr->regs = regs;
5117 regs_intr->abi = perf_reg_abi(current);
5122 * Get remaining task size from user stack pointer.
5124 * It'd be better to take stack vma map and limit this more
5125 * precisly, but there's no way to get it safely under interrupt,
5126 * so using TASK_SIZE as limit.
5128 static u64 perf_ustack_task_size(struct pt_regs *regs)
5130 unsigned long addr = perf_user_stack_pointer(regs);
5132 if (!addr || addr >= TASK_SIZE)
5135 return TASK_SIZE - addr;
5139 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5140 struct pt_regs *regs)
5144 /* No regs, no stack pointer, no dump. */
5149 * Check if we fit in with the requested stack size into the:
5151 * If we don't, we limit the size to the TASK_SIZE.
5153 * - remaining sample size
5154 * If we don't, we customize the stack size to
5155 * fit in to the remaining sample size.
5158 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5159 stack_size = min(stack_size, (u16) task_size);
5161 /* Current header size plus static size and dynamic size. */
5162 header_size += 2 * sizeof(u64);
5164 /* Do we fit in with the current stack dump size? */
5165 if ((u16) (header_size + stack_size) < header_size) {
5167 * If we overflow the maximum size for the sample,
5168 * we customize the stack dump size to fit in.
5170 stack_size = USHRT_MAX - header_size - sizeof(u64);
5171 stack_size = round_up(stack_size, sizeof(u64));
5178 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5179 struct pt_regs *regs)
5181 /* Case of a kernel thread, nothing to dump */
5184 perf_output_put(handle, size);
5193 * - the size requested by user or the best one we can fit
5194 * in to the sample max size
5196 * - user stack dump data
5198 * - the actual dumped size
5202 perf_output_put(handle, dump_size);
5205 sp = perf_user_stack_pointer(regs);
5206 rem = __output_copy_user(handle, (void *) sp, dump_size);
5207 dyn_size = dump_size - rem;
5209 perf_output_skip(handle, rem);
5212 perf_output_put(handle, dyn_size);
5216 static void __perf_event_header__init_id(struct perf_event_header *header,
5217 struct perf_sample_data *data,
5218 struct perf_event *event)
5220 u64 sample_type = event->attr.sample_type;
5222 data->type = sample_type;
5223 header->size += event->id_header_size;
5225 if (sample_type & PERF_SAMPLE_TID) {
5226 /* namespace issues */
5227 data->tid_entry.pid = perf_event_pid(event, current);
5228 data->tid_entry.tid = perf_event_tid(event, current);
5231 if (sample_type & PERF_SAMPLE_TIME)
5232 data->time = perf_event_clock(event);
5234 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5235 data->id = primary_event_id(event);
5237 if (sample_type & PERF_SAMPLE_STREAM_ID)
5238 data->stream_id = event->id;
5240 if (sample_type & PERF_SAMPLE_CPU) {
5241 data->cpu_entry.cpu = raw_smp_processor_id();
5242 data->cpu_entry.reserved = 0;
5246 void perf_event_header__init_id(struct perf_event_header *header,
5247 struct perf_sample_data *data,
5248 struct perf_event *event)
5250 if (event->attr.sample_id_all)
5251 __perf_event_header__init_id(header, data, event);
5254 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5255 struct perf_sample_data *data)
5257 u64 sample_type = data->type;
5259 if (sample_type & PERF_SAMPLE_TID)
5260 perf_output_put(handle, data->tid_entry);
5262 if (sample_type & PERF_SAMPLE_TIME)
5263 perf_output_put(handle, data->time);
5265 if (sample_type & PERF_SAMPLE_ID)
5266 perf_output_put(handle, data->id);
5268 if (sample_type & PERF_SAMPLE_STREAM_ID)
5269 perf_output_put(handle, data->stream_id);
5271 if (sample_type & PERF_SAMPLE_CPU)
5272 perf_output_put(handle, data->cpu_entry);
5274 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5275 perf_output_put(handle, data->id);
5278 void perf_event__output_id_sample(struct perf_event *event,
5279 struct perf_output_handle *handle,
5280 struct perf_sample_data *sample)
5282 if (event->attr.sample_id_all)
5283 __perf_event__output_id_sample(handle, sample);
5286 static void perf_output_read_one(struct perf_output_handle *handle,
5287 struct perf_event *event,
5288 u64 enabled, u64 running)
5290 u64 read_format = event->attr.read_format;
5294 values[n++] = perf_event_count(event);
5295 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5296 values[n++] = enabled +
5297 atomic64_read(&event->child_total_time_enabled);
5299 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5300 values[n++] = running +
5301 atomic64_read(&event->child_total_time_running);
5303 if (read_format & PERF_FORMAT_ID)
5304 values[n++] = primary_event_id(event);
5306 __output_copy(handle, values, n * sizeof(u64));
5310 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5312 static void perf_output_read_group(struct perf_output_handle *handle,
5313 struct perf_event *event,
5314 u64 enabled, u64 running)
5316 struct perf_event *leader = event->group_leader, *sub;
5317 u64 read_format = event->attr.read_format;
5321 values[n++] = 1 + leader->nr_siblings;
5323 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5324 values[n++] = enabled;
5326 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5327 values[n++] = running;
5329 if (leader != event)
5330 leader->pmu->read(leader);
5332 values[n++] = perf_event_count(leader);
5333 if (read_format & PERF_FORMAT_ID)
5334 values[n++] = primary_event_id(leader);
5336 __output_copy(handle, values, n * sizeof(u64));
5338 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5341 if ((sub != event) &&
5342 (sub->state == PERF_EVENT_STATE_ACTIVE))
5343 sub->pmu->read(sub);
5345 values[n++] = perf_event_count(sub);
5346 if (read_format & PERF_FORMAT_ID)
5347 values[n++] = primary_event_id(sub);
5349 __output_copy(handle, values, n * sizeof(u64));
5353 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5354 PERF_FORMAT_TOTAL_TIME_RUNNING)
5356 static void perf_output_read(struct perf_output_handle *handle,
5357 struct perf_event *event)
5359 u64 enabled = 0, running = 0, now;
5360 u64 read_format = event->attr.read_format;
5363 * compute total_time_enabled, total_time_running
5364 * based on snapshot values taken when the event
5365 * was last scheduled in.
5367 * we cannot simply called update_context_time()
5368 * because of locking issue as we are called in
5371 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5372 calc_timer_values(event, &now, &enabled, &running);
5374 if (event->attr.read_format & PERF_FORMAT_GROUP)
5375 perf_output_read_group(handle, event, enabled, running);
5377 perf_output_read_one(handle, event, enabled, running);
5380 void perf_output_sample(struct perf_output_handle *handle,
5381 struct perf_event_header *header,
5382 struct perf_sample_data *data,
5383 struct perf_event *event)
5385 u64 sample_type = data->type;
5387 perf_output_put(handle, *header);
5389 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5390 perf_output_put(handle, data->id);
5392 if (sample_type & PERF_SAMPLE_IP)
5393 perf_output_put(handle, data->ip);
5395 if (sample_type & PERF_SAMPLE_TID)
5396 perf_output_put(handle, data->tid_entry);
5398 if (sample_type & PERF_SAMPLE_TIME)
5399 perf_output_put(handle, data->time);
5401 if (sample_type & PERF_SAMPLE_ADDR)
5402 perf_output_put(handle, data->addr);
5404 if (sample_type & PERF_SAMPLE_ID)
5405 perf_output_put(handle, data->id);
5407 if (sample_type & PERF_SAMPLE_STREAM_ID)
5408 perf_output_put(handle, data->stream_id);
5410 if (sample_type & PERF_SAMPLE_CPU)
5411 perf_output_put(handle, data->cpu_entry);
5413 if (sample_type & PERF_SAMPLE_PERIOD)
5414 perf_output_put(handle, data->period);
5416 if (sample_type & PERF_SAMPLE_READ)
5417 perf_output_read(handle, event);
5419 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5420 if (data->callchain) {
5423 if (data->callchain)
5424 size += data->callchain->nr;
5426 size *= sizeof(u64);
5428 __output_copy(handle, data->callchain, size);
5431 perf_output_put(handle, nr);
5435 if (sample_type & PERF_SAMPLE_RAW) {
5437 u32 raw_size = data->raw->size;
5438 u32 real_size = round_up(raw_size + sizeof(u32),
5439 sizeof(u64)) - sizeof(u32);
5442 perf_output_put(handle, real_size);
5443 __output_copy(handle, data->raw->data, raw_size);
5444 if (real_size - raw_size)
5445 __output_copy(handle, &zero, real_size - raw_size);
5451 .size = sizeof(u32),
5454 perf_output_put(handle, raw);
5458 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5459 if (data->br_stack) {
5462 size = data->br_stack->nr
5463 * sizeof(struct perf_branch_entry);
5465 perf_output_put(handle, data->br_stack->nr);
5466 perf_output_copy(handle, data->br_stack->entries, size);
5469 * we always store at least the value of nr
5472 perf_output_put(handle, nr);
5476 if (sample_type & PERF_SAMPLE_REGS_USER) {
5477 u64 abi = data->regs_user.abi;
5480 * If there are no regs to dump, notice it through
5481 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5483 perf_output_put(handle, abi);
5486 u64 mask = event->attr.sample_regs_user;
5487 perf_output_sample_regs(handle,
5488 data->regs_user.regs,
5493 if (sample_type & PERF_SAMPLE_STACK_USER) {
5494 perf_output_sample_ustack(handle,
5495 data->stack_user_size,
5496 data->regs_user.regs);
5499 if (sample_type & PERF_SAMPLE_WEIGHT)
5500 perf_output_put(handle, data->weight);
5502 if (sample_type & PERF_SAMPLE_DATA_SRC)
5503 perf_output_put(handle, data->data_src.val);
5505 if (sample_type & PERF_SAMPLE_TRANSACTION)
5506 perf_output_put(handle, data->txn);
5508 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5509 u64 abi = data->regs_intr.abi;
5511 * If there are no regs to dump, notice it through
5512 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5514 perf_output_put(handle, abi);
5517 u64 mask = event->attr.sample_regs_intr;
5519 perf_output_sample_regs(handle,
5520 data->regs_intr.regs,
5525 if (!event->attr.watermark) {
5526 int wakeup_events = event->attr.wakeup_events;
5528 if (wakeup_events) {
5529 struct ring_buffer *rb = handle->rb;
5530 int events = local_inc_return(&rb->events);
5532 if (events >= wakeup_events) {
5533 local_sub(wakeup_events, &rb->events);
5534 local_inc(&rb->wakeup);
5540 void perf_prepare_sample(struct perf_event_header *header,
5541 struct perf_sample_data *data,
5542 struct perf_event *event,
5543 struct pt_regs *regs)
5545 u64 sample_type = event->attr.sample_type;
5547 header->type = PERF_RECORD_SAMPLE;
5548 header->size = sizeof(*header) + event->header_size;
5551 header->misc |= perf_misc_flags(regs);
5553 __perf_event_header__init_id(header, data, event);
5555 if (sample_type & PERF_SAMPLE_IP)
5556 data->ip = perf_instruction_pointer(regs);
5558 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5561 data->callchain = perf_callchain(event, regs);
5563 if (data->callchain)
5564 size += data->callchain->nr;
5566 header->size += size * sizeof(u64);
5569 if (sample_type & PERF_SAMPLE_RAW) {
5570 int size = sizeof(u32);
5573 size += data->raw->size;
5575 size += sizeof(u32);
5577 header->size += round_up(size, sizeof(u64));
5580 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5581 int size = sizeof(u64); /* nr */
5582 if (data->br_stack) {
5583 size += data->br_stack->nr
5584 * sizeof(struct perf_branch_entry);
5586 header->size += size;
5589 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5590 perf_sample_regs_user(&data->regs_user, regs,
5591 &data->regs_user_copy);
5593 if (sample_type & PERF_SAMPLE_REGS_USER) {
5594 /* regs dump ABI info */
5595 int size = sizeof(u64);
5597 if (data->regs_user.regs) {
5598 u64 mask = event->attr.sample_regs_user;
5599 size += hweight64(mask) * sizeof(u64);
5602 header->size += size;
5605 if (sample_type & PERF_SAMPLE_STACK_USER) {
5607 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5608 * processed as the last one or have additional check added
5609 * in case new sample type is added, because we could eat
5610 * up the rest of the sample size.
5612 u16 stack_size = event->attr.sample_stack_user;
5613 u16 size = sizeof(u64);
5615 stack_size = perf_sample_ustack_size(stack_size, header->size,
5616 data->regs_user.regs);
5619 * If there is something to dump, add space for the dump
5620 * itself and for the field that tells the dynamic size,
5621 * which is how many have been actually dumped.
5624 size += sizeof(u64) + stack_size;
5626 data->stack_user_size = stack_size;
5627 header->size += size;
5630 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5631 /* regs dump ABI info */
5632 int size = sizeof(u64);
5634 perf_sample_regs_intr(&data->regs_intr, regs);
5636 if (data->regs_intr.regs) {
5637 u64 mask = event->attr.sample_regs_intr;
5639 size += hweight64(mask) * sizeof(u64);
5642 header->size += size;
5646 void perf_event_output(struct perf_event *event,
5647 struct perf_sample_data *data,
5648 struct pt_regs *regs)
5650 struct perf_output_handle handle;
5651 struct perf_event_header header;
5653 /* protect the callchain buffers */
5656 perf_prepare_sample(&header, data, event, regs);
5658 if (perf_output_begin(&handle, event, header.size))
5661 perf_output_sample(&handle, &header, data, event);
5663 perf_output_end(&handle);
5673 struct perf_read_event {
5674 struct perf_event_header header;
5681 perf_event_read_event(struct perf_event *event,
5682 struct task_struct *task)
5684 struct perf_output_handle handle;
5685 struct perf_sample_data sample;
5686 struct perf_read_event read_event = {
5688 .type = PERF_RECORD_READ,
5690 .size = sizeof(read_event) + event->read_size,
5692 .pid = perf_event_pid(event, task),
5693 .tid = perf_event_tid(event, task),
5697 perf_event_header__init_id(&read_event.header, &sample, event);
5698 ret = perf_output_begin(&handle, event, read_event.header.size);
5702 perf_output_put(&handle, read_event);
5703 perf_output_read(&handle, event);
5704 perf_event__output_id_sample(event, &handle, &sample);
5706 perf_output_end(&handle);
5709 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5712 perf_event_aux_ctx(struct perf_event_context *ctx,
5713 perf_event_aux_output_cb output,
5716 struct perf_event *event;
5718 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5719 if (event->state < PERF_EVENT_STATE_INACTIVE)
5721 if (!event_filter_match(event))
5723 output(event, data);
5728 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5729 struct perf_event_context *task_ctx)
5733 perf_event_aux_ctx(task_ctx, output, data);
5739 perf_event_aux(perf_event_aux_output_cb output, void *data,
5740 struct perf_event_context *task_ctx)
5742 struct perf_cpu_context *cpuctx;
5743 struct perf_event_context *ctx;
5748 * If we have task_ctx != NULL we only notify
5749 * the task context itself. The task_ctx is set
5750 * only for EXIT events before releasing task
5754 perf_event_aux_task_ctx(output, data, task_ctx);
5759 list_for_each_entry_rcu(pmu, &pmus, entry) {
5760 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5761 if (cpuctx->unique_pmu != pmu)
5763 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5764 ctxn = pmu->task_ctx_nr;
5767 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5769 perf_event_aux_ctx(ctx, output, data);
5771 put_cpu_ptr(pmu->pmu_cpu_context);
5776 struct remote_output {
5777 struct ring_buffer *rb;
5781 static void __perf_event_output_stop(struct perf_event *event, void *data)
5783 struct perf_event *parent = event->parent;
5784 struct remote_output *ro = data;
5785 struct ring_buffer *rb = ro->rb;
5787 if (!has_aux(event))
5794 * In case of inheritance, it will be the parent that links to the
5795 * ring-buffer, but it will be the child that's actually using it:
5797 if (rcu_dereference(parent->rb) == rb)
5798 ro->err = __perf_event_stop(event);
5801 static int __perf_pmu_output_stop(void *info)
5803 struct perf_event *event = info;
5804 struct pmu *pmu = event->pmu;
5805 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5806 struct remote_output ro = {
5811 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro);
5812 if (cpuctx->task_ctx)
5813 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop,
5820 static void perf_pmu_output_stop(struct perf_event *event)
5822 struct perf_event *iter;
5827 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
5829 * For per-CPU events, we need to make sure that neither they
5830 * nor their children are running; for cpu==-1 events it's
5831 * sufficient to stop the event itself if it's active, since
5832 * it can't have children.
5836 cpu = READ_ONCE(iter->oncpu);
5841 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
5842 if (err == -EAGAIN) {
5851 * task tracking -- fork/exit
5853 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5856 struct perf_task_event {
5857 struct task_struct *task;
5858 struct perf_event_context *task_ctx;
5861 struct perf_event_header header;
5871 static int perf_event_task_match(struct perf_event *event)
5873 return event->attr.comm || event->attr.mmap ||
5874 event->attr.mmap2 || event->attr.mmap_data ||
5878 static void perf_event_task_output(struct perf_event *event,
5881 struct perf_task_event *task_event = data;
5882 struct perf_output_handle handle;
5883 struct perf_sample_data sample;
5884 struct task_struct *task = task_event->task;
5885 int ret, size = task_event->event_id.header.size;
5887 if (!perf_event_task_match(event))
5890 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5892 ret = perf_output_begin(&handle, event,
5893 task_event->event_id.header.size);
5897 task_event->event_id.pid = perf_event_pid(event, task);
5898 task_event->event_id.ppid = perf_event_pid(event, current);
5900 task_event->event_id.tid = perf_event_tid(event, task);
5901 task_event->event_id.ptid = perf_event_tid(event, current);
5903 task_event->event_id.time = perf_event_clock(event);
5905 perf_output_put(&handle, task_event->event_id);
5907 perf_event__output_id_sample(event, &handle, &sample);
5909 perf_output_end(&handle);
5911 task_event->event_id.header.size = size;
5914 static void perf_event_task(struct task_struct *task,
5915 struct perf_event_context *task_ctx,
5918 struct perf_task_event task_event;
5920 if (!atomic_read(&nr_comm_events) &&
5921 !atomic_read(&nr_mmap_events) &&
5922 !atomic_read(&nr_task_events))
5925 task_event = (struct perf_task_event){
5927 .task_ctx = task_ctx,
5930 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5932 .size = sizeof(task_event.event_id),
5942 perf_event_aux(perf_event_task_output,
5947 void perf_event_fork(struct task_struct *task)
5949 perf_event_task(task, NULL, 1);
5956 struct perf_comm_event {
5957 struct task_struct *task;
5962 struct perf_event_header header;
5969 static int perf_event_comm_match(struct perf_event *event)
5971 return event->attr.comm;
5974 static void perf_event_comm_output(struct perf_event *event,
5977 struct perf_comm_event *comm_event = data;
5978 struct perf_output_handle handle;
5979 struct perf_sample_data sample;
5980 int size = comm_event->event_id.header.size;
5983 if (!perf_event_comm_match(event))
5986 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5987 ret = perf_output_begin(&handle, event,
5988 comm_event->event_id.header.size);
5993 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5994 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5996 perf_output_put(&handle, comm_event->event_id);
5997 __output_copy(&handle, comm_event->comm,
5998 comm_event->comm_size);
6000 perf_event__output_id_sample(event, &handle, &sample);
6002 perf_output_end(&handle);
6004 comm_event->event_id.header.size = size;
6007 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6009 char comm[TASK_COMM_LEN];
6012 memset(comm, 0, sizeof(comm));
6013 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6014 size = ALIGN(strlen(comm)+1, sizeof(u64));
6016 comm_event->comm = comm;
6017 comm_event->comm_size = size;
6019 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6021 perf_event_aux(perf_event_comm_output,
6026 void perf_event_comm(struct task_struct *task, bool exec)
6028 struct perf_comm_event comm_event;
6030 if (!atomic_read(&nr_comm_events))
6033 comm_event = (struct perf_comm_event){
6039 .type = PERF_RECORD_COMM,
6040 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6048 perf_event_comm_event(&comm_event);
6055 struct perf_mmap_event {
6056 struct vm_area_struct *vma;
6058 const char *file_name;
6066 struct perf_event_header header;
6076 static int perf_event_mmap_match(struct perf_event *event,
6079 struct perf_mmap_event *mmap_event = data;
6080 struct vm_area_struct *vma = mmap_event->vma;
6081 int executable = vma->vm_flags & VM_EXEC;
6083 return (!executable && event->attr.mmap_data) ||
6084 (executable && (event->attr.mmap || event->attr.mmap2));
6087 static void perf_event_mmap_output(struct perf_event *event,
6090 struct perf_mmap_event *mmap_event = data;
6091 struct perf_output_handle handle;
6092 struct perf_sample_data sample;
6093 int size = mmap_event->event_id.header.size;
6096 if (!perf_event_mmap_match(event, data))
6099 if (event->attr.mmap2) {
6100 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6101 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6102 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6103 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6104 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6105 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6106 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6109 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6110 ret = perf_output_begin(&handle, event,
6111 mmap_event->event_id.header.size);
6115 mmap_event->event_id.pid = perf_event_pid(event, current);
6116 mmap_event->event_id.tid = perf_event_tid(event, current);
6118 perf_output_put(&handle, mmap_event->event_id);
6120 if (event->attr.mmap2) {
6121 perf_output_put(&handle, mmap_event->maj);
6122 perf_output_put(&handle, mmap_event->min);
6123 perf_output_put(&handle, mmap_event->ino);
6124 perf_output_put(&handle, mmap_event->ino_generation);
6125 perf_output_put(&handle, mmap_event->prot);
6126 perf_output_put(&handle, mmap_event->flags);
6129 __output_copy(&handle, mmap_event->file_name,
6130 mmap_event->file_size);
6132 perf_event__output_id_sample(event, &handle, &sample);
6134 perf_output_end(&handle);
6136 mmap_event->event_id.header.size = size;
6139 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6141 struct vm_area_struct *vma = mmap_event->vma;
6142 struct file *file = vma->vm_file;
6143 int maj = 0, min = 0;
6144 u64 ino = 0, gen = 0;
6145 u32 prot = 0, flags = 0;
6152 struct inode *inode;
6155 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6161 * d_path() works from the end of the rb backwards, so we
6162 * need to add enough zero bytes after the string to handle
6163 * the 64bit alignment we do later.
6165 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6170 inode = file_inode(vma->vm_file);
6171 dev = inode->i_sb->s_dev;
6173 gen = inode->i_generation;
6177 if (vma->vm_flags & VM_READ)
6179 if (vma->vm_flags & VM_WRITE)
6181 if (vma->vm_flags & VM_EXEC)
6184 if (vma->vm_flags & VM_MAYSHARE)
6187 flags = MAP_PRIVATE;
6189 if (vma->vm_flags & VM_DENYWRITE)
6190 flags |= MAP_DENYWRITE;
6191 if (vma->vm_flags & VM_MAYEXEC)
6192 flags |= MAP_EXECUTABLE;
6193 if (vma->vm_flags & VM_LOCKED)
6194 flags |= MAP_LOCKED;
6195 if (vma->vm_flags & VM_HUGETLB)
6196 flags |= MAP_HUGETLB;
6200 if (vma->vm_ops && vma->vm_ops->name) {
6201 name = (char *) vma->vm_ops->name(vma);
6206 name = (char *)arch_vma_name(vma);
6210 if (vma->vm_start <= vma->vm_mm->start_brk &&
6211 vma->vm_end >= vma->vm_mm->brk) {
6215 if (vma->vm_start <= vma->vm_mm->start_stack &&
6216 vma->vm_end >= vma->vm_mm->start_stack) {
6226 strlcpy(tmp, name, sizeof(tmp));
6230 * Since our buffer works in 8 byte units we need to align our string
6231 * size to a multiple of 8. However, we must guarantee the tail end is
6232 * zero'd out to avoid leaking random bits to userspace.
6234 size = strlen(name)+1;
6235 while (!IS_ALIGNED(size, sizeof(u64)))
6236 name[size++] = '\0';
6238 mmap_event->file_name = name;
6239 mmap_event->file_size = size;
6240 mmap_event->maj = maj;
6241 mmap_event->min = min;
6242 mmap_event->ino = ino;
6243 mmap_event->ino_generation = gen;
6244 mmap_event->prot = prot;
6245 mmap_event->flags = flags;
6247 if (!(vma->vm_flags & VM_EXEC))
6248 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6250 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6252 perf_event_aux(perf_event_mmap_output,
6259 void perf_event_mmap(struct vm_area_struct *vma)
6261 struct perf_mmap_event mmap_event;
6263 if (!atomic_read(&nr_mmap_events))
6266 mmap_event = (struct perf_mmap_event){
6272 .type = PERF_RECORD_MMAP,
6273 .misc = PERF_RECORD_MISC_USER,
6278 .start = vma->vm_start,
6279 .len = vma->vm_end - vma->vm_start,
6280 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6282 /* .maj (attr_mmap2 only) */
6283 /* .min (attr_mmap2 only) */
6284 /* .ino (attr_mmap2 only) */
6285 /* .ino_generation (attr_mmap2 only) */
6286 /* .prot (attr_mmap2 only) */
6287 /* .flags (attr_mmap2 only) */
6290 perf_event_mmap_event(&mmap_event);
6293 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6294 unsigned long size, u64 flags)
6296 struct perf_output_handle handle;
6297 struct perf_sample_data sample;
6298 struct perf_aux_event {
6299 struct perf_event_header header;
6305 .type = PERF_RECORD_AUX,
6307 .size = sizeof(rec),
6315 perf_event_header__init_id(&rec.header, &sample, event);
6316 ret = perf_output_begin(&handle, event, rec.header.size);
6321 perf_output_put(&handle, rec);
6322 perf_event__output_id_sample(event, &handle, &sample);
6324 perf_output_end(&handle);
6328 * Lost/dropped samples logging
6330 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6332 struct perf_output_handle handle;
6333 struct perf_sample_data sample;
6337 struct perf_event_header header;
6339 } lost_samples_event = {
6341 .type = PERF_RECORD_LOST_SAMPLES,
6343 .size = sizeof(lost_samples_event),
6348 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6350 ret = perf_output_begin(&handle, event,
6351 lost_samples_event.header.size);
6355 perf_output_put(&handle, lost_samples_event);
6356 perf_event__output_id_sample(event, &handle, &sample);
6357 perf_output_end(&handle);
6361 * context_switch tracking
6364 struct perf_switch_event {
6365 struct task_struct *task;
6366 struct task_struct *next_prev;
6369 struct perf_event_header header;
6375 static int perf_event_switch_match(struct perf_event *event)
6377 return event->attr.context_switch;
6380 static void perf_event_switch_output(struct perf_event *event, void *data)
6382 struct perf_switch_event *se = data;
6383 struct perf_output_handle handle;
6384 struct perf_sample_data sample;
6387 if (!perf_event_switch_match(event))
6390 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6391 if (event->ctx->task) {
6392 se->event_id.header.type = PERF_RECORD_SWITCH;
6393 se->event_id.header.size = sizeof(se->event_id.header);
6395 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6396 se->event_id.header.size = sizeof(se->event_id);
6397 se->event_id.next_prev_pid =
6398 perf_event_pid(event, se->next_prev);
6399 se->event_id.next_prev_tid =
6400 perf_event_tid(event, se->next_prev);
6403 perf_event_header__init_id(&se->event_id.header, &sample, event);
6405 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6409 if (event->ctx->task)
6410 perf_output_put(&handle, se->event_id.header);
6412 perf_output_put(&handle, se->event_id);
6414 perf_event__output_id_sample(event, &handle, &sample);
6416 perf_output_end(&handle);
6419 static void perf_event_switch(struct task_struct *task,
6420 struct task_struct *next_prev, bool sched_in)
6422 struct perf_switch_event switch_event;
6424 /* N.B. caller checks nr_switch_events != 0 */
6426 switch_event = (struct perf_switch_event){
6428 .next_prev = next_prev,
6432 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6435 /* .next_prev_pid */
6436 /* .next_prev_tid */
6440 perf_event_aux(perf_event_switch_output,
6446 * IRQ throttle logging
6449 static void perf_log_throttle(struct perf_event *event, int enable)
6451 struct perf_output_handle handle;
6452 struct perf_sample_data sample;
6456 struct perf_event_header header;
6460 } throttle_event = {
6462 .type = PERF_RECORD_THROTTLE,
6464 .size = sizeof(throttle_event),
6466 .time = perf_event_clock(event),
6467 .id = primary_event_id(event),
6468 .stream_id = event->id,
6472 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6474 perf_event_header__init_id(&throttle_event.header, &sample, event);
6476 ret = perf_output_begin(&handle, event,
6477 throttle_event.header.size);
6481 perf_output_put(&handle, throttle_event);
6482 perf_event__output_id_sample(event, &handle, &sample);
6483 perf_output_end(&handle);
6486 static void perf_log_itrace_start(struct perf_event *event)
6488 struct perf_output_handle handle;
6489 struct perf_sample_data sample;
6490 struct perf_aux_event {
6491 struct perf_event_header header;
6498 event = event->parent;
6500 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6501 event->hw.itrace_started)
6504 rec.header.type = PERF_RECORD_ITRACE_START;
6505 rec.header.misc = 0;
6506 rec.header.size = sizeof(rec);
6507 rec.pid = perf_event_pid(event, current);
6508 rec.tid = perf_event_tid(event, current);
6510 perf_event_header__init_id(&rec.header, &sample, event);
6511 ret = perf_output_begin(&handle, event, rec.header.size);
6516 perf_output_put(&handle, rec);
6517 perf_event__output_id_sample(event, &handle, &sample);
6519 perf_output_end(&handle);
6523 * Generic event overflow handling, sampling.
6526 static int __perf_event_overflow(struct perf_event *event,
6527 int throttle, struct perf_sample_data *data,
6528 struct pt_regs *regs)
6530 int events = atomic_read(&event->event_limit);
6531 struct hw_perf_event *hwc = &event->hw;
6536 * Non-sampling counters might still use the PMI to fold short
6537 * hardware counters, ignore those.
6539 if (unlikely(!is_sampling_event(event)))
6542 seq = __this_cpu_read(perf_throttled_seq);
6543 if (seq != hwc->interrupts_seq) {
6544 hwc->interrupts_seq = seq;
6545 hwc->interrupts = 1;
6548 if (unlikely(throttle
6549 && hwc->interrupts >= max_samples_per_tick)) {
6550 __this_cpu_inc(perf_throttled_count);
6551 hwc->interrupts = MAX_INTERRUPTS;
6552 perf_log_throttle(event, 0);
6553 tick_nohz_full_kick();
6558 if (event->attr.freq) {
6559 u64 now = perf_clock();
6560 s64 delta = now - hwc->freq_time_stamp;
6562 hwc->freq_time_stamp = now;
6564 if (delta > 0 && delta < 2*TICK_NSEC)
6565 perf_adjust_period(event, delta, hwc->last_period, true);
6569 * XXX event_limit might not quite work as expected on inherited
6573 event->pending_kill = POLL_IN;
6574 if (events && atomic_dec_and_test(&event->event_limit)) {
6576 event->pending_kill = POLL_HUP;
6577 event->pending_disable = 1;
6578 irq_work_queue(&event->pending);
6581 if (event->overflow_handler)
6582 event->overflow_handler(event, data, regs);
6584 perf_event_output(event, data, regs);
6586 if (*perf_event_fasync(event) && event->pending_kill) {
6587 event->pending_wakeup = 1;
6588 irq_work_queue(&event->pending);
6594 int perf_event_overflow(struct perf_event *event,
6595 struct perf_sample_data *data,
6596 struct pt_regs *regs)
6598 return __perf_event_overflow(event, 1, data, regs);
6602 * Generic software event infrastructure
6605 struct swevent_htable {
6606 struct swevent_hlist *swevent_hlist;
6607 struct mutex hlist_mutex;
6610 /* Recursion avoidance in each contexts */
6611 int recursion[PERF_NR_CONTEXTS];
6614 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6617 * We directly increment event->count and keep a second value in
6618 * event->hw.period_left to count intervals. This period event
6619 * is kept in the range [-sample_period, 0] so that we can use the
6623 u64 perf_swevent_set_period(struct perf_event *event)
6625 struct hw_perf_event *hwc = &event->hw;
6626 u64 period = hwc->last_period;
6630 hwc->last_period = hwc->sample_period;
6633 old = val = local64_read(&hwc->period_left);
6637 nr = div64_u64(period + val, period);
6638 offset = nr * period;
6640 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6646 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6647 struct perf_sample_data *data,
6648 struct pt_regs *regs)
6650 struct hw_perf_event *hwc = &event->hw;
6654 overflow = perf_swevent_set_period(event);
6656 if (hwc->interrupts == MAX_INTERRUPTS)
6659 for (; overflow; overflow--) {
6660 if (__perf_event_overflow(event, throttle,
6663 * We inhibit the overflow from happening when
6664 * hwc->interrupts == MAX_INTERRUPTS.
6672 static void perf_swevent_event(struct perf_event *event, u64 nr,
6673 struct perf_sample_data *data,
6674 struct pt_regs *regs)
6676 struct hw_perf_event *hwc = &event->hw;
6678 local64_add(nr, &event->count);
6683 if (!is_sampling_event(event))
6686 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6688 return perf_swevent_overflow(event, 1, data, regs);
6690 data->period = event->hw.last_period;
6692 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6693 return perf_swevent_overflow(event, 1, data, regs);
6695 if (local64_add_negative(nr, &hwc->period_left))
6698 perf_swevent_overflow(event, 0, data, regs);
6701 static int perf_exclude_event(struct perf_event *event,
6702 struct pt_regs *regs)
6704 if (event->hw.state & PERF_HES_STOPPED)
6708 if (event->attr.exclude_user && user_mode(regs))
6711 if (event->attr.exclude_kernel && !user_mode(regs))
6718 static int perf_swevent_match(struct perf_event *event,
6719 enum perf_type_id type,
6721 struct perf_sample_data *data,
6722 struct pt_regs *regs)
6724 if (event->attr.type != type)
6727 if (event->attr.config != event_id)
6730 if (perf_exclude_event(event, regs))
6736 static inline u64 swevent_hash(u64 type, u32 event_id)
6738 u64 val = event_id | (type << 32);
6740 return hash_64(val, SWEVENT_HLIST_BITS);
6743 static inline struct hlist_head *
6744 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6746 u64 hash = swevent_hash(type, event_id);
6748 return &hlist->heads[hash];
6751 /* For the read side: events when they trigger */
6752 static inline struct hlist_head *
6753 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6755 struct swevent_hlist *hlist;
6757 hlist = rcu_dereference(swhash->swevent_hlist);
6761 return __find_swevent_head(hlist, type, event_id);
6764 /* For the event head insertion and removal in the hlist */
6765 static inline struct hlist_head *
6766 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6768 struct swevent_hlist *hlist;
6769 u32 event_id = event->attr.config;
6770 u64 type = event->attr.type;
6773 * Event scheduling is always serialized against hlist allocation
6774 * and release. Which makes the protected version suitable here.
6775 * The context lock guarantees that.
6777 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6778 lockdep_is_held(&event->ctx->lock));
6782 return __find_swevent_head(hlist, type, event_id);
6785 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6787 struct perf_sample_data *data,
6788 struct pt_regs *regs)
6790 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6791 struct perf_event *event;
6792 struct hlist_head *head;
6795 head = find_swevent_head_rcu(swhash, type, event_id);
6799 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6800 if (perf_swevent_match(event, type, event_id, data, regs))
6801 perf_swevent_event(event, nr, data, regs);
6807 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6809 int perf_swevent_get_recursion_context(void)
6811 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6813 return get_recursion_context(swhash->recursion);
6815 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6817 inline void perf_swevent_put_recursion_context(int rctx)
6819 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6821 put_recursion_context(swhash->recursion, rctx);
6824 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6826 struct perf_sample_data data;
6828 if (WARN_ON_ONCE(!regs))
6831 perf_sample_data_init(&data, addr, 0);
6832 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6835 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6839 preempt_disable_notrace();
6840 rctx = perf_swevent_get_recursion_context();
6841 if (unlikely(rctx < 0))
6844 ___perf_sw_event(event_id, nr, regs, addr);
6846 perf_swevent_put_recursion_context(rctx);
6848 preempt_enable_notrace();
6851 static void perf_swevent_read(struct perf_event *event)
6855 static int perf_swevent_add(struct perf_event *event, int flags)
6857 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6858 struct hw_perf_event *hwc = &event->hw;
6859 struct hlist_head *head;
6861 if (is_sampling_event(event)) {
6862 hwc->last_period = hwc->sample_period;
6863 perf_swevent_set_period(event);
6866 hwc->state = !(flags & PERF_EF_START);
6868 head = find_swevent_head(swhash, event);
6869 if (WARN_ON_ONCE(!head))
6872 hlist_add_head_rcu(&event->hlist_entry, head);
6873 perf_event_update_userpage(event);
6878 static void perf_swevent_del(struct perf_event *event, int flags)
6880 hlist_del_rcu(&event->hlist_entry);
6883 static void perf_swevent_start(struct perf_event *event, int flags)
6885 event->hw.state = 0;
6888 static void perf_swevent_stop(struct perf_event *event, int flags)
6890 event->hw.state = PERF_HES_STOPPED;
6893 /* Deref the hlist from the update side */
6894 static inline struct swevent_hlist *
6895 swevent_hlist_deref(struct swevent_htable *swhash)
6897 return rcu_dereference_protected(swhash->swevent_hlist,
6898 lockdep_is_held(&swhash->hlist_mutex));
6901 static void swevent_hlist_release(struct swevent_htable *swhash)
6903 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6908 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6909 kfree_rcu(hlist, rcu_head);
6912 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6914 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6916 mutex_lock(&swhash->hlist_mutex);
6918 if (!--swhash->hlist_refcount)
6919 swevent_hlist_release(swhash);
6921 mutex_unlock(&swhash->hlist_mutex);
6924 static void swevent_hlist_put(struct perf_event *event)
6928 for_each_possible_cpu(cpu)
6929 swevent_hlist_put_cpu(event, cpu);
6932 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6934 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6937 mutex_lock(&swhash->hlist_mutex);
6938 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6939 struct swevent_hlist *hlist;
6941 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6946 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6948 swhash->hlist_refcount++;
6950 mutex_unlock(&swhash->hlist_mutex);
6955 static int swevent_hlist_get(struct perf_event *event)
6958 int cpu, failed_cpu;
6961 for_each_possible_cpu(cpu) {
6962 err = swevent_hlist_get_cpu(event, cpu);
6972 for_each_possible_cpu(cpu) {
6973 if (cpu == failed_cpu)
6975 swevent_hlist_put_cpu(event, cpu);
6982 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6984 static void sw_perf_event_destroy(struct perf_event *event)
6986 u64 event_id = event->attr.config;
6988 WARN_ON(event->parent);
6990 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6991 swevent_hlist_put(event);
6994 static int perf_swevent_init(struct perf_event *event)
6996 u64 event_id = event->attr.config;
6998 if (event->attr.type != PERF_TYPE_SOFTWARE)
7002 * no branch sampling for software events
7004 if (has_branch_stack(event))
7008 case PERF_COUNT_SW_CPU_CLOCK:
7009 case PERF_COUNT_SW_TASK_CLOCK:
7016 if (event_id >= PERF_COUNT_SW_MAX)
7019 if (!event->parent) {
7022 err = swevent_hlist_get(event);
7026 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7027 event->destroy = sw_perf_event_destroy;
7033 static struct pmu perf_swevent = {
7034 .task_ctx_nr = perf_sw_context,
7036 .capabilities = PERF_PMU_CAP_NO_NMI,
7038 .event_init = perf_swevent_init,
7039 .add = perf_swevent_add,
7040 .del = perf_swevent_del,
7041 .start = perf_swevent_start,
7042 .stop = perf_swevent_stop,
7043 .read = perf_swevent_read,
7046 #ifdef CONFIG_EVENT_TRACING
7048 static int perf_tp_filter_match(struct perf_event *event,
7049 struct perf_sample_data *data)
7051 void *record = data->raw->data;
7053 /* only top level events have filters set */
7055 event = event->parent;
7057 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7062 static int perf_tp_event_match(struct perf_event *event,
7063 struct perf_sample_data *data,
7064 struct pt_regs *regs)
7066 if (event->hw.state & PERF_HES_STOPPED)
7069 * All tracepoints are from kernel-space.
7071 if (event->attr.exclude_kernel)
7074 if (!perf_tp_filter_match(event, data))
7080 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
7081 struct pt_regs *regs, struct hlist_head *head, int rctx,
7082 struct task_struct *task)
7084 struct perf_sample_data data;
7085 struct perf_event *event;
7087 struct perf_raw_record raw = {
7092 perf_sample_data_init(&data, addr, 0);
7095 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7096 if (perf_tp_event_match(event, &data, regs))
7097 perf_swevent_event(event, count, &data, regs);
7101 * If we got specified a target task, also iterate its context and
7102 * deliver this event there too.
7104 if (task && task != current) {
7105 struct perf_event_context *ctx;
7106 struct trace_entry *entry = record;
7109 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7113 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7114 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7116 if (event->attr.config != entry->type)
7118 if (perf_tp_event_match(event, &data, regs))
7119 perf_swevent_event(event, count, &data, regs);
7125 perf_swevent_put_recursion_context(rctx);
7127 EXPORT_SYMBOL_GPL(perf_tp_event);
7129 static void tp_perf_event_destroy(struct perf_event *event)
7131 perf_trace_destroy(event);
7134 static int perf_tp_event_init(struct perf_event *event)
7138 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7142 * no branch sampling for tracepoint events
7144 if (has_branch_stack(event))
7147 err = perf_trace_init(event);
7151 event->destroy = tp_perf_event_destroy;
7156 static struct pmu perf_tracepoint = {
7157 .task_ctx_nr = perf_sw_context,
7159 .event_init = perf_tp_event_init,
7160 .add = perf_trace_add,
7161 .del = perf_trace_del,
7162 .start = perf_swevent_start,
7163 .stop = perf_swevent_stop,
7164 .read = perf_swevent_read,
7167 static inline void perf_tp_register(void)
7169 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7172 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7177 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7180 filter_str = strndup_user(arg, PAGE_SIZE);
7181 if (IS_ERR(filter_str))
7182 return PTR_ERR(filter_str);
7184 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7190 static void perf_event_free_filter(struct perf_event *event)
7192 ftrace_profile_free_filter(event);
7195 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7197 struct bpf_prog *prog;
7199 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7202 if (event->tp_event->prog)
7205 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7206 /* bpf programs can only be attached to u/kprobes */
7209 prog = bpf_prog_get(prog_fd);
7211 return PTR_ERR(prog);
7213 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7214 /* valid fd, but invalid bpf program type */
7219 event->tp_event->prog = prog;
7224 static void perf_event_free_bpf_prog(struct perf_event *event)
7226 struct bpf_prog *prog;
7228 if (!event->tp_event)
7231 prog = event->tp_event->prog;
7233 event->tp_event->prog = NULL;
7234 bpf_prog_put_rcu(prog);
7240 static inline void perf_tp_register(void)
7244 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7249 static void perf_event_free_filter(struct perf_event *event)
7253 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7258 static void perf_event_free_bpf_prog(struct perf_event *event)
7261 #endif /* CONFIG_EVENT_TRACING */
7263 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7264 void perf_bp_event(struct perf_event *bp, void *data)
7266 struct perf_sample_data sample;
7267 struct pt_regs *regs = data;
7269 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7271 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7272 perf_swevent_event(bp, 1, &sample, regs);
7276 static int perf_event_drv_configs(struct perf_event *event,
7279 if (!event->pmu->get_drv_configs)
7282 return event->pmu->get_drv_configs(event, arg);
7286 * hrtimer based swevent callback
7289 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7291 enum hrtimer_restart ret = HRTIMER_RESTART;
7292 struct perf_sample_data data;
7293 struct pt_regs *regs;
7294 struct perf_event *event;
7297 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7299 if (event->state != PERF_EVENT_STATE_ACTIVE)
7300 return HRTIMER_NORESTART;
7302 event->pmu->read(event);
7304 perf_sample_data_init(&data, 0, event->hw.last_period);
7305 regs = get_irq_regs();
7307 if (regs && !perf_exclude_event(event, regs)) {
7308 if (!(event->attr.exclude_idle && is_idle_task(current)))
7309 if (__perf_event_overflow(event, 1, &data, regs))
7310 ret = HRTIMER_NORESTART;
7313 period = max_t(u64, 10000, event->hw.sample_period);
7314 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7319 static void perf_swevent_start_hrtimer(struct perf_event *event)
7321 struct hw_perf_event *hwc = &event->hw;
7324 if (!is_sampling_event(event))
7327 period = local64_read(&hwc->period_left);
7332 local64_set(&hwc->period_left, 0);
7334 period = max_t(u64, 10000, hwc->sample_period);
7336 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7337 HRTIMER_MODE_REL_PINNED);
7340 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7342 struct hw_perf_event *hwc = &event->hw;
7344 if (is_sampling_event(event)) {
7345 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7346 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7348 hrtimer_cancel(&hwc->hrtimer);
7352 static void perf_swevent_init_hrtimer(struct perf_event *event)
7354 struct hw_perf_event *hwc = &event->hw;
7356 if (!is_sampling_event(event))
7359 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7360 hwc->hrtimer.function = perf_swevent_hrtimer;
7363 * Since hrtimers have a fixed rate, we can do a static freq->period
7364 * mapping and avoid the whole period adjust feedback stuff.
7366 if (event->attr.freq) {
7367 long freq = event->attr.sample_freq;
7369 event->attr.sample_period = NSEC_PER_SEC / freq;
7370 hwc->sample_period = event->attr.sample_period;
7371 local64_set(&hwc->period_left, hwc->sample_period);
7372 hwc->last_period = hwc->sample_period;
7373 event->attr.freq = 0;
7378 * Software event: cpu wall time clock
7381 static void cpu_clock_event_update(struct perf_event *event)
7386 now = local_clock();
7387 prev = local64_xchg(&event->hw.prev_count, now);
7388 local64_add(now - prev, &event->count);
7391 static void cpu_clock_event_start(struct perf_event *event, int flags)
7393 local64_set(&event->hw.prev_count, local_clock());
7394 perf_swevent_start_hrtimer(event);
7397 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7399 perf_swevent_cancel_hrtimer(event);
7400 cpu_clock_event_update(event);
7403 static int cpu_clock_event_add(struct perf_event *event, int flags)
7405 if (flags & PERF_EF_START)
7406 cpu_clock_event_start(event, flags);
7407 perf_event_update_userpage(event);
7412 static void cpu_clock_event_del(struct perf_event *event, int flags)
7414 cpu_clock_event_stop(event, flags);
7417 static void cpu_clock_event_read(struct perf_event *event)
7419 cpu_clock_event_update(event);
7422 static int cpu_clock_event_init(struct perf_event *event)
7424 if (event->attr.type != PERF_TYPE_SOFTWARE)
7427 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7431 * no branch sampling for software events
7433 if (has_branch_stack(event))
7436 perf_swevent_init_hrtimer(event);
7441 static struct pmu perf_cpu_clock = {
7442 .task_ctx_nr = perf_sw_context,
7444 .capabilities = PERF_PMU_CAP_NO_NMI,
7446 .event_init = cpu_clock_event_init,
7447 .add = cpu_clock_event_add,
7448 .del = cpu_clock_event_del,
7449 .start = cpu_clock_event_start,
7450 .stop = cpu_clock_event_stop,
7451 .read = cpu_clock_event_read,
7455 * Software event: task time clock
7458 static void task_clock_event_update(struct perf_event *event, u64 now)
7463 prev = local64_xchg(&event->hw.prev_count, now);
7465 local64_add(delta, &event->count);
7468 static void task_clock_event_start(struct perf_event *event, int flags)
7470 local64_set(&event->hw.prev_count, event->ctx->time);
7471 perf_swevent_start_hrtimer(event);
7474 static void task_clock_event_stop(struct perf_event *event, int flags)
7476 perf_swevent_cancel_hrtimer(event);
7477 task_clock_event_update(event, event->ctx->time);
7480 static int task_clock_event_add(struct perf_event *event, int flags)
7482 if (flags & PERF_EF_START)
7483 task_clock_event_start(event, flags);
7484 perf_event_update_userpage(event);
7489 static void task_clock_event_del(struct perf_event *event, int flags)
7491 task_clock_event_stop(event, PERF_EF_UPDATE);
7494 static void task_clock_event_read(struct perf_event *event)
7496 u64 now = perf_clock();
7497 u64 delta = now - event->ctx->timestamp;
7498 u64 time = event->ctx->time + delta;
7500 task_clock_event_update(event, time);
7503 static int task_clock_event_init(struct perf_event *event)
7505 if (event->attr.type != PERF_TYPE_SOFTWARE)
7508 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7512 * no branch sampling for software events
7514 if (has_branch_stack(event))
7517 perf_swevent_init_hrtimer(event);
7522 static struct pmu perf_task_clock = {
7523 .task_ctx_nr = perf_sw_context,
7525 .capabilities = PERF_PMU_CAP_NO_NMI,
7527 .event_init = task_clock_event_init,
7528 .add = task_clock_event_add,
7529 .del = task_clock_event_del,
7530 .start = task_clock_event_start,
7531 .stop = task_clock_event_stop,
7532 .read = task_clock_event_read,
7535 static void perf_pmu_nop_void(struct pmu *pmu)
7539 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7543 static int perf_pmu_nop_int(struct pmu *pmu)
7548 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7550 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7552 __this_cpu_write(nop_txn_flags, flags);
7554 if (flags & ~PERF_PMU_TXN_ADD)
7557 perf_pmu_disable(pmu);
7560 static int perf_pmu_commit_txn(struct pmu *pmu)
7562 unsigned int flags = __this_cpu_read(nop_txn_flags);
7564 __this_cpu_write(nop_txn_flags, 0);
7566 if (flags & ~PERF_PMU_TXN_ADD)
7569 perf_pmu_enable(pmu);
7573 static void perf_pmu_cancel_txn(struct pmu *pmu)
7575 unsigned int flags = __this_cpu_read(nop_txn_flags);
7577 __this_cpu_write(nop_txn_flags, 0);
7579 if (flags & ~PERF_PMU_TXN_ADD)
7582 perf_pmu_enable(pmu);
7585 static int perf_event_idx_default(struct perf_event *event)
7591 * Ensures all contexts with the same task_ctx_nr have the same
7592 * pmu_cpu_context too.
7594 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7601 list_for_each_entry(pmu, &pmus, entry) {
7602 if (pmu->task_ctx_nr == ctxn)
7603 return pmu->pmu_cpu_context;
7609 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7613 for_each_possible_cpu(cpu) {
7614 struct perf_cpu_context *cpuctx;
7616 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7618 if (cpuctx->unique_pmu == old_pmu)
7619 cpuctx->unique_pmu = pmu;
7623 static void free_pmu_context(struct pmu *pmu)
7627 mutex_lock(&pmus_lock);
7629 * Like a real lame refcount.
7631 list_for_each_entry(i, &pmus, entry) {
7632 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7633 update_pmu_context(i, pmu);
7638 free_percpu(pmu->pmu_cpu_context);
7640 mutex_unlock(&pmus_lock);
7642 static struct idr pmu_idr;
7645 type_show(struct device *dev, struct device_attribute *attr, char *page)
7647 struct pmu *pmu = dev_get_drvdata(dev);
7649 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7651 static DEVICE_ATTR_RO(type);
7654 perf_event_mux_interval_ms_show(struct device *dev,
7655 struct device_attribute *attr,
7658 struct pmu *pmu = dev_get_drvdata(dev);
7660 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7663 static DEFINE_MUTEX(mux_interval_mutex);
7666 perf_event_mux_interval_ms_store(struct device *dev,
7667 struct device_attribute *attr,
7668 const char *buf, size_t count)
7670 struct pmu *pmu = dev_get_drvdata(dev);
7671 int timer, cpu, ret;
7673 ret = kstrtoint(buf, 0, &timer);
7680 /* same value, noting to do */
7681 if (timer == pmu->hrtimer_interval_ms)
7684 mutex_lock(&mux_interval_mutex);
7685 pmu->hrtimer_interval_ms = timer;
7687 /* update all cpuctx for this PMU */
7689 for_each_online_cpu(cpu) {
7690 struct perf_cpu_context *cpuctx;
7691 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7692 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7694 cpu_function_call(cpu,
7695 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7698 mutex_unlock(&mux_interval_mutex);
7702 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7704 static struct attribute *pmu_dev_attrs[] = {
7705 &dev_attr_type.attr,
7706 &dev_attr_perf_event_mux_interval_ms.attr,
7709 ATTRIBUTE_GROUPS(pmu_dev);
7711 static int pmu_bus_running;
7712 static struct bus_type pmu_bus = {
7713 .name = "event_source",
7714 .dev_groups = pmu_dev_groups,
7717 static void pmu_dev_release(struct device *dev)
7722 static int pmu_dev_alloc(struct pmu *pmu)
7726 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7730 pmu->dev->groups = pmu->attr_groups;
7731 device_initialize(pmu->dev);
7732 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7736 dev_set_drvdata(pmu->dev, pmu);
7737 pmu->dev->bus = &pmu_bus;
7738 pmu->dev->release = pmu_dev_release;
7739 ret = device_add(pmu->dev);
7747 put_device(pmu->dev);
7751 static struct lock_class_key cpuctx_mutex;
7752 static struct lock_class_key cpuctx_lock;
7754 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7758 mutex_lock(&pmus_lock);
7760 pmu->pmu_disable_count = alloc_percpu(int);
7761 if (!pmu->pmu_disable_count)
7770 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7778 if (pmu_bus_running) {
7779 ret = pmu_dev_alloc(pmu);
7785 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7786 if (pmu->pmu_cpu_context)
7787 goto got_cpu_context;
7790 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7791 if (!pmu->pmu_cpu_context)
7794 for_each_possible_cpu(cpu) {
7795 struct perf_cpu_context *cpuctx;
7797 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7798 __perf_event_init_context(&cpuctx->ctx);
7799 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7800 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7801 cpuctx->ctx.pmu = pmu;
7803 __perf_mux_hrtimer_init(cpuctx, cpu);
7805 cpuctx->unique_pmu = pmu;
7809 if (!pmu->start_txn) {
7810 if (pmu->pmu_enable) {
7812 * If we have pmu_enable/pmu_disable calls, install
7813 * transaction stubs that use that to try and batch
7814 * hardware accesses.
7816 pmu->start_txn = perf_pmu_start_txn;
7817 pmu->commit_txn = perf_pmu_commit_txn;
7818 pmu->cancel_txn = perf_pmu_cancel_txn;
7820 pmu->start_txn = perf_pmu_nop_txn;
7821 pmu->commit_txn = perf_pmu_nop_int;
7822 pmu->cancel_txn = perf_pmu_nop_void;
7826 if (!pmu->pmu_enable) {
7827 pmu->pmu_enable = perf_pmu_nop_void;
7828 pmu->pmu_disable = perf_pmu_nop_void;
7831 if (!pmu->event_idx)
7832 pmu->event_idx = perf_event_idx_default;
7834 list_add_rcu(&pmu->entry, &pmus);
7835 atomic_set(&pmu->exclusive_cnt, 0);
7838 mutex_unlock(&pmus_lock);
7843 device_del(pmu->dev);
7844 put_device(pmu->dev);
7847 if (pmu->type >= PERF_TYPE_MAX)
7848 idr_remove(&pmu_idr, pmu->type);
7851 free_percpu(pmu->pmu_disable_count);
7854 EXPORT_SYMBOL_GPL(perf_pmu_register);
7856 void perf_pmu_unregister(struct pmu *pmu)
7858 mutex_lock(&pmus_lock);
7859 list_del_rcu(&pmu->entry);
7860 mutex_unlock(&pmus_lock);
7863 * We dereference the pmu list under both SRCU and regular RCU, so
7864 * synchronize against both of those.
7866 synchronize_srcu(&pmus_srcu);
7869 free_percpu(pmu->pmu_disable_count);
7870 if (pmu->type >= PERF_TYPE_MAX)
7871 idr_remove(&pmu_idr, pmu->type);
7872 device_del(pmu->dev);
7873 put_device(pmu->dev);
7874 free_pmu_context(pmu);
7876 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7878 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7880 struct perf_event_context *ctx = NULL;
7883 if (!try_module_get(pmu->module))
7886 if (event->group_leader != event) {
7888 * This ctx->mutex can nest when we're called through
7889 * inheritance. See the perf_event_ctx_lock_nested() comment.
7891 ctx = perf_event_ctx_lock_nested(event->group_leader,
7892 SINGLE_DEPTH_NESTING);
7897 ret = pmu->event_init(event);
7900 perf_event_ctx_unlock(event->group_leader, ctx);
7903 module_put(pmu->module);
7908 static struct pmu *perf_init_event(struct perf_event *event)
7910 struct pmu *pmu = NULL;
7914 idx = srcu_read_lock(&pmus_srcu);
7917 pmu = idr_find(&pmu_idr, event->attr.type);
7920 ret = perf_try_init_event(pmu, event);
7926 list_for_each_entry_rcu(pmu, &pmus, entry) {
7927 ret = perf_try_init_event(pmu, event);
7931 if (ret != -ENOENT) {
7936 pmu = ERR_PTR(-ENOENT);
7938 srcu_read_unlock(&pmus_srcu, idx);
7943 static void account_event_cpu(struct perf_event *event, int cpu)
7948 if (is_cgroup_event(event))
7949 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7952 static void account_event(struct perf_event *event)
7957 if (event->attach_state & PERF_ATTACH_TASK)
7958 static_key_slow_inc(&perf_sched_events.key);
7959 if (event->attr.mmap || event->attr.mmap_data)
7960 atomic_inc(&nr_mmap_events);
7961 if (event->attr.comm)
7962 atomic_inc(&nr_comm_events);
7963 if (event->attr.task)
7964 atomic_inc(&nr_task_events);
7965 if (event->attr.freq) {
7966 if (atomic_inc_return(&nr_freq_events) == 1)
7967 tick_nohz_full_kick_all();
7969 if (event->attr.context_switch) {
7970 atomic_inc(&nr_switch_events);
7971 static_key_slow_inc(&perf_sched_events.key);
7973 if (has_branch_stack(event))
7974 static_key_slow_inc(&perf_sched_events.key);
7975 if (is_cgroup_event(event))
7976 static_key_slow_inc(&perf_sched_events.key);
7978 account_event_cpu(event, event->cpu);
7982 * Allocate and initialize a event structure
7984 static struct perf_event *
7985 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7986 struct task_struct *task,
7987 struct perf_event *group_leader,
7988 struct perf_event *parent_event,
7989 perf_overflow_handler_t overflow_handler,
7990 void *context, int cgroup_fd)
7993 struct perf_event *event;
7994 struct hw_perf_event *hwc;
7997 if ((unsigned)cpu >= nr_cpu_ids) {
7998 if (!task || cpu != -1)
7999 return ERR_PTR(-EINVAL);
8002 event = kzalloc(sizeof(*event), GFP_KERNEL);
8004 return ERR_PTR(-ENOMEM);
8007 * Single events are their own group leaders, with an
8008 * empty sibling list:
8011 group_leader = event;
8013 mutex_init(&event->child_mutex);
8014 INIT_LIST_HEAD(&event->child_list);
8016 INIT_LIST_HEAD(&event->group_entry);
8017 INIT_LIST_HEAD(&event->event_entry);
8018 INIT_LIST_HEAD(&event->sibling_list);
8019 INIT_LIST_HEAD(&event->rb_entry);
8020 INIT_LIST_HEAD(&event->active_entry);
8021 INIT_LIST_HEAD(&event->drv_configs);
8022 INIT_HLIST_NODE(&event->hlist_entry);
8025 init_waitqueue_head(&event->waitq);
8026 init_irq_work(&event->pending, perf_pending_event);
8028 mutex_init(&event->mmap_mutex);
8030 atomic_long_set(&event->refcount, 1);
8032 event->attr = *attr;
8033 event->group_leader = group_leader;
8037 event->parent = parent_event;
8039 event->ns = get_pid_ns(task_active_pid_ns(current));
8040 event->id = atomic64_inc_return(&perf_event_id);
8042 event->state = PERF_EVENT_STATE_INACTIVE;
8045 event->attach_state = PERF_ATTACH_TASK;
8047 * XXX pmu::event_init needs to know what task to account to
8048 * and we cannot use the ctx information because we need the
8049 * pmu before we get a ctx.
8051 event->hw.target = task;
8054 event->clock = &local_clock;
8056 event->clock = parent_event->clock;
8058 if (!overflow_handler && parent_event) {
8059 overflow_handler = parent_event->overflow_handler;
8060 context = parent_event->overflow_handler_context;
8063 event->overflow_handler = overflow_handler;
8064 event->overflow_handler_context = context;
8066 perf_event__state_init(event);
8071 hwc->sample_period = attr->sample_period;
8072 if (attr->freq && attr->sample_freq)
8073 hwc->sample_period = 1;
8074 hwc->last_period = hwc->sample_period;
8076 local64_set(&hwc->period_left, hwc->sample_period);
8079 * we currently do not support PERF_FORMAT_GROUP on inherited events
8081 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8084 if (!has_branch_stack(event))
8085 event->attr.branch_sample_type = 0;
8087 if (cgroup_fd != -1) {
8088 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8093 pmu = perf_init_event(event);
8096 else if (IS_ERR(pmu)) {
8101 err = exclusive_event_init(event);
8105 if (!event->parent) {
8106 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8107 err = get_callchain_buffers();
8113 /* symmetric to unaccount_event() in _free_event() */
8114 account_event(event);
8119 exclusive_event_destroy(event);
8123 event->destroy(event);
8124 module_put(pmu->module);
8126 if (is_cgroup_event(event))
8127 perf_detach_cgroup(event);
8129 put_pid_ns(event->ns);
8132 return ERR_PTR(err);
8135 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8136 struct perf_event_attr *attr)
8141 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8145 * zero the full structure, so that a short copy will be nice.
8147 memset(attr, 0, sizeof(*attr));
8149 ret = get_user(size, &uattr->size);
8153 if (size > PAGE_SIZE) /* silly large */
8156 if (!size) /* abi compat */
8157 size = PERF_ATTR_SIZE_VER0;
8159 if (size < PERF_ATTR_SIZE_VER0)
8163 * If we're handed a bigger struct than we know of,
8164 * ensure all the unknown bits are 0 - i.e. new
8165 * user-space does not rely on any kernel feature
8166 * extensions we dont know about yet.
8168 if (size > sizeof(*attr)) {
8169 unsigned char __user *addr;
8170 unsigned char __user *end;
8173 addr = (void __user *)uattr + sizeof(*attr);
8174 end = (void __user *)uattr + size;
8176 for (; addr < end; addr++) {
8177 ret = get_user(val, addr);
8183 size = sizeof(*attr);
8186 ret = copy_from_user(attr, uattr, size);
8190 if (attr->__reserved_1)
8193 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8196 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8199 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8200 u64 mask = attr->branch_sample_type;
8202 /* only using defined bits */
8203 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8206 /* at least one branch bit must be set */
8207 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8210 /* propagate priv level, when not set for branch */
8211 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8213 /* exclude_kernel checked on syscall entry */
8214 if (!attr->exclude_kernel)
8215 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8217 if (!attr->exclude_user)
8218 mask |= PERF_SAMPLE_BRANCH_USER;
8220 if (!attr->exclude_hv)
8221 mask |= PERF_SAMPLE_BRANCH_HV;
8223 * adjust user setting (for HW filter setup)
8225 attr->branch_sample_type = mask;
8227 /* privileged levels capture (kernel, hv): check permissions */
8228 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8229 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8233 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8234 ret = perf_reg_validate(attr->sample_regs_user);
8239 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8240 if (!arch_perf_have_user_stack_dump())
8244 * We have __u32 type for the size, but so far
8245 * we can only use __u16 as maximum due to the
8246 * __u16 sample size limit.
8248 if (attr->sample_stack_user >= USHRT_MAX)
8250 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8254 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8255 ret = perf_reg_validate(attr->sample_regs_intr);
8260 put_user(sizeof(*attr), &uattr->size);
8266 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8268 struct ring_buffer *rb = NULL;
8274 /* don't allow circular references */
8275 if (event == output_event)
8279 * Don't allow cross-cpu buffers
8281 if (output_event->cpu != event->cpu)
8285 * If its not a per-cpu rb, it must be the same task.
8287 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8291 * Mixing clocks in the same buffer is trouble you don't need.
8293 if (output_event->clock != event->clock)
8297 * If both events generate aux data, they must be on the same PMU
8299 if (has_aux(event) && has_aux(output_event) &&
8300 event->pmu != output_event->pmu)
8304 mutex_lock(&event->mmap_mutex);
8305 /* Can't redirect output if we've got an active mmap() */
8306 if (atomic_read(&event->mmap_count))
8310 /* get the rb we want to redirect to */
8311 rb = ring_buffer_get(output_event);
8316 ring_buffer_attach(event, rb);
8320 mutex_unlock(&event->mmap_mutex);
8326 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8332 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8335 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8337 bool nmi_safe = false;
8340 case CLOCK_MONOTONIC:
8341 event->clock = &ktime_get_mono_fast_ns;
8345 case CLOCK_MONOTONIC_RAW:
8346 event->clock = &ktime_get_raw_fast_ns;
8350 case CLOCK_REALTIME:
8351 event->clock = &ktime_get_real_ns;
8354 case CLOCK_BOOTTIME:
8355 event->clock = &ktime_get_boot_ns;
8359 event->clock = &ktime_get_tai_ns;
8366 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8373 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8375 * @attr_uptr: event_id type attributes for monitoring/sampling
8378 * @group_fd: group leader event fd
8380 SYSCALL_DEFINE5(perf_event_open,
8381 struct perf_event_attr __user *, attr_uptr,
8382 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8384 struct perf_event *group_leader = NULL, *output_event = NULL;
8385 struct perf_event *event, *sibling;
8386 struct perf_event_attr attr;
8387 struct perf_event_context *ctx, *uninitialized_var(gctx);
8388 struct file *event_file = NULL;
8389 struct fd group = {NULL, 0};
8390 struct task_struct *task = NULL;
8395 int f_flags = O_RDWR;
8398 /* for future expandability... */
8399 if (flags & ~PERF_FLAG_ALL)
8402 if (perf_paranoid_any() && !capable(CAP_SYS_ADMIN))
8405 err = perf_copy_attr(attr_uptr, &attr);
8409 if (!attr.exclude_kernel) {
8410 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8415 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8418 if (attr.sample_period & (1ULL << 63))
8423 * In cgroup mode, the pid argument is used to pass the fd
8424 * opened to the cgroup directory in cgroupfs. The cpu argument
8425 * designates the cpu on which to monitor threads from that
8428 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8431 if (flags & PERF_FLAG_FD_CLOEXEC)
8432 f_flags |= O_CLOEXEC;
8434 event_fd = get_unused_fd_flags(f_flags);
8438 if (group_fd != -1) {
8439 err = perf_fget_light(group_fd, &group);
8442 group_leader = group.file->private_data;
8443 if (flags & PERF_FLAG_FD_OUTPUT)
8444 output_event = group_leader;
8445 if (flags & PERF_FLAG_FD_NO_GROUP)
8446 group_leader = NULL;
8449 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8450 task = find_lively_task_by_vpid(pid);
8452 err = PTR_ERR(task);
8457 if (task && group_leader &&
8458 group_leader->attr.inherit != attr.inherit) {
8466 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
8471 * Reuse ptrace permission checks for now.
8473 * We must hold cred_guard_mutex across this and any potential
8474 * perf_install_in_context() call for this new event to
8475 * serialize against exec() altering our credentials (and the
8476 * perf_event_exit_task() that could imply).
8479 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
8483 if (flags & PERF_FLAG_PID_CGROUP)
8486 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8487 NULL, NULL, cgroup_fd);
8488 if (IS_ERR(event)) {
8489 err = PTR_ERR(event);
8493 if (is_sampling_event(event)) {
8494 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8501 * Special case software events and allow them to be part of
8502 * any hardware group.
8506 if (attr.use_clockid) {
8507 err = perf_event_set_clock(event, attr.clockid);
8513 (is_software_event(event) != is_software_event(group_leader))) {
8514 if (is_software_event(event)) {
8516 * If event and group_leader are not both a software
8517 * event, and event is, then group leader is not.
8519 * Allow the addition of software events to !software
8520 * groups, this is safe because software events never
8523 pmu = group_leader->pmu;
8524 } else if (is_software_event(group_leader) &&
8525 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8527 * In case the group is a pure software group, and we
8528 * try to add a hardware event, move the whole group to
8529 * the hardware context.
8536 * Get the target context (task or percpu):
8538 ctx = find_get_context(pmu, task, event);
8544 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8550 * Look up the group leader (we will attach this event to it):
8556 * Do not allow a recursive hierarchy (this new sibling
8557 * becoming part of another group-sibling):
8559 if (group_leader->group_leader != group_leader)
8562 /* All events in a group should have the same clock */
8563 if (group_leader->clock != event->clock)
8567 * Do not allow to attach to a group in a different
8568 * task or CPU context:
8572 * Make sure we're both on the same task, or both
8575 if (group_leader->ctx->task != ctx->task)
8579 * Make sure we're both events for the same CPU;
8580 * grouping events for different CPUs is broken; since
8581 * you can never concurrently schedule them anyhow.
8583 if (group_leader->cpu != event->cpu)
8586 if (group_leader->ctx != ctx)
8591 * Only a group leader can be exclusive or pinned
8593 if (attr.exclusive || attr.pinned)
8598 err = perf_event_set_output(event, output_event);
8603 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8605 if (IS_ERR(event_file)) {
8606 err = PTR_ERR(event_file);
8612 gctx = group_leader->ctx;
8613 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8615 mutex_lock(&ctx->mutex);
8618 if (!perf_event_validate_size(event)) {
8624 * Must be under the same ctx::mutex as perf_install_in_context(),
8625 * because we need to serialize with concurrent event creation.
8627 if (!exclusive_event_installable(event, ctx)) {
8628 /* exclusive and group stuff are assumed mutually exclusive */
8629 WARN_ON_ONCE(move_group);
8635 WARN_ON_ONCE(ctx->parent_ctx);
8638 * This is the point on no return; we cannot fail hereafter. This is
8639 * where we start modifying current state.
8644 * See perf_event_ctx_lock() for comments on the details
8645 * of swizzling perf_event::ctx.
8647 perf_remove_from_context(group_leader, false);
8649 list_for_each_entry(sibling, &group_leader->sibling_list,
8651 perf_remove_from_context(sibling, false);
8656 * Wait for everybody to stop referencing the events through
8657 * the old lists, before installing it on new lists.
8662 * Install the group siblings before the group leader.
8664 * Because a group leader will try and install the entire group
8665 * (through the sibling list, which is still in-tact), we can
8666 * end up with siblings installed in the wrong context.
8668 * By installing siblings first we NO-OP because they're not
8669 * reachable through the group lists.
8671 list_for_each_entry(sibling, &group_leader->sibling_list,
8673 perf_event__state_init(sibling);
8674 perf_install_in_context(ctx, sibling, sibling->cpu);
8679 * Removing from the context ends up with disabled
8680 * event. What we want here is event in the initial
8681 * startup state, ready to be add into new context.
8683 perf_event__state_init(group_leader);
8684 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8688 * Now that all events are installed in @ctx, nothing
8689 * references @gctx anymore, so drop the last reference we have
8696 * Precalculate sample_data sizes; do while holding ctx::mutex such
8697 * that we're serialized against further additions and before
8698 * perf_install_in_context() which is the point the event is active and
8699 * can use these values.
8701 perf_event__header_size(event);
8702 perf_event__id_header_size(event);
8704 perf_install_in_context(ctx, event, event->cpu);
8705 perf_unpin_context(ctx);
8708 mutex_unlock(&gctx->mutex);
8709 mutex_unlock(&ctx->mutex);
8712 mutex_unlock(&task->signal->cred_guard_mutex);
8713 put_task_struct(task);
8718 event->owner = current;
8720 mutex_lock(¤t->perf_event_mutex);
8721 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8722 mutex_unlock(¤t->perf_event_mutex);
8725 * Drop the reference on the group_event after placing the
8726 * new event on the sibling_list. This ensures destruction
8727 * of the group leader will find the pointer to itself in
8728 * perf_group_detach().
8731 fd_install(event_fd, event_file);
8736 mutex_unlock(&gctx->mutex);
8737 mutex_unlock(&ctx->mutex);
8741 perf_unpin_context(ctx);
8745 * If event_file is set, the fput() above will have called ->release()
8746 * and that will take care of freeing the event.
8752 mutex_unlock(&task->signal->cred_guard_mutex);
8757 put_task_struct(task);
8761 put_unused_fd(event_fd);
8766 * perf_event_create_kernel_counter
8768 * @attr: attributes of the counter to create
8769 * @cpu: cpu in which the counter is bound
8770 * @task: task to profile (NULL for percpu)
8773 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8774 struct task_struct *task,
8775 perf_overflow_handler_t overflow_handler,
8778 struct perf_event_context *ctx;
8779 struct perf_event *event;
8783 * Get the target context (task or percpu):
8786 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8787 overflow_handler, context, -1);
8788 if (IS_ERR(event)) {
8789 err = PTR_ERR(event);
8793 /* Mark owner so we could distinguish it from user events. */
8794 event->owner = EVENT_OWNER_KERNEL;
8796 ctx = find_get_context(event->pmu, task, event);
8802 WARN_ON_ONCE(ctx->parent_ctx);
8803 mutex_lock(&ctx->mutex);
8804 if (!exclusive_event_installable(event, ctx)) {
8805 mutex_unlock(&ctx->mutex);
8806 perf_unpin_context(ctx);
8812 perf_install_in_context(ctx, event, cpu);
8813 perf_unpin_context(ctx);
8814 mutex_unlock(&ctx->mutex);
8821 return ERR_PTR(err);
8823 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8825 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8827 struct perf_event_context *src_ctx;
8828 struct perf_event_context *dst_ctx;
8829 struct perf_event *event, *tmp;
8832 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8833 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8836 * See perf_event_ctx_lock() for comments on the details
8837 * of swizzling perf_event::ctx.
8839 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8840 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8842 perf_remove_from_context(event, false);
8843 unaccount_event_cpu(event, src_cpu);
8845 list_add(&event->migrate_entry, &events);
8849 * Wait for the events to quiesce before re-instating them.
8854 * Re-instate events in 2 passes.
8856 * Skip over group leaders and only install siblings on this first
8857 * pass, siblings will not get enabled without a leader, however a
8858 * leader will enable its siblings, even if those are still on the old
8861 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8862 if (event->group_leader == event)
8865 list_del(&event->migrate_entry);
8866 if (event->state >= PERF_EVENT_STATE_OFF)
8867 event->state = PERF_EVENT_STATE_INACTIVE;
8868 account_event_cpu(event, dst_cpu);
8869 perf_install_in_context(dst_ctx, event, dst_cpu);
8874 * Once all the siblings are setup properly, install the group leaders
8877 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8878 list_del(&event->migrate_entry);
8879 if (event->state >= PERF_EVENT_STATE_OFF)
8880 event->state = PERF_EVENT_STATE_INACTIVE;
8881 account_event_cpu(event, dst_cpu);
8882 perf_install_in_context(dst_ctx, event, dst_cpu);
8885 mutex_unlock(&dst_ctx->mutex);
8886 mutex_unlock(&src_ctx->mutex);
8888 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8890 static void sync_child_event(struct perf_event *child_event,
8891 struct task_struct *child)
8893 struct perf_event *parent_event = child_event->parent;
8896 if (child_event->attr.inherit_stat)
8897 perf_event_read_event(child_event, child);
8899 child_val = perf_event_count(child_event);
8902 * Add back the child's count to the parent's count:
8904 atomic64_add(child_val, &parent_event->child_count);
8905 atomic64_add(child_event->total_time_enabled,
8906 &parent_event->child_total_time_enabled);
8907 atomic64_add(child_event->total_time_running,
8908 &parent_event->child_total_time_running);
8911 * Remove this event from the parent's list
8913 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8914 mutex_lock(&parent_event->child_mutex);
8915 list_del_init(&child_event->child_list);
8916 mutex_unlock(&parent_event->child_mutex);
8919 * Make sure user/parent get notified, that we just
8922 perf_event_wakeup(parent_event);
8925 * Release the parent event, if this was the last
8928 put_event(parent_event);
8932 __perf_event_exit_task(struct perf_event *child_event,
8933 struct perf_event_context *child_ctx,
8934 struct task_struct *child)
8937 * Do not destroy the 'original' grouping; because of the context
8938 * switch optimization the original events could've ended up in a
8939 * random child task.
8941 * If we were to destroy the original group, all group related
8942 * operations would cease to function properly after this random
8945 * Do destroy all inherited groups, we don't care about those
8946 * and being thorough is better.
8948 perf_remove_from_context(child_event, !!child_event->parent);
8951 * It can happen that the parent exits first, and has events
8952 * that are still around due to the child reference. These
8953 * events need to be zapped.
8955 if (child_event->parent) {
8956 sync_child_event(child_event, child);
8957 free_event(child_event);
8959 child_event->state = PERF_EVENT_STATE_EXIT;
8960 perf_event_wakeup(child_event);
8964 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8966 struct perf_event *child_event, *next;
8967 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8968 unsigned long flags;
8970 if (likely(!child->perf_event_ctxp[ctxn]))
8973 local_irq_save(flags);
8975 * We can't reschedule here because interrupts are disabled,
8976 * and either child is current or it is a task that can't be
8977 * scheduled, so we are now safe from rescheduling changing
8980 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8983 * Take the context lock here so that if find_get_context is
8984 * reading child->perf_event_ctxp, we wait until it has
8985 * incremented the context's refcount before we do put_ctx below.
8987 raw_spin_lock(&child_ctx->lock);
8988 task_ctx_sched_out(child_ctx);
8989 child->perf_event_ctxp[ctxn] = NULL;
8992 * If this context is a clone; unclone it so it can't get
8993 * swapped to another process while we're removing all
8994 * the events from it.
8996 clone_ctx = unclone_ctx(child_ctx);
8997 update_context_time(child_ctx);
8998 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9004 * Report the task dead after unscheduling the events so that we
9005 * won't get any samples after PERF_RECORD_EXIT. We can however still
9006 * get a few PERF_RECORD_READ events.
9008 perf_event_task(child, child_ctx, 0);
9011 * We can recurse on the same lock type through:
9013 * __perf_event_exit_task()
9014 * sync_child_event()
9016 * mutex_lock(&ctx->mutex)
9018 * But since its the parent context it won't be the same instance.
9020 mutex_lock(&child_ctx->mutex);
9022 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9023 __perf_event_exit_task(child_event, child_ctx, child);
9025 mutex_unlock(&child_ctx->mutex);
9031 * When a child task exits, feed back event values to parent events.
9033 * Can be called with cred_guard_mutex held when called from
9034 * install_exec_creds().
9036 void perf_event_exit_task(struct task_struct *child)
9038 struct perf_event *event, *tmp;
9041 mutex_lock(&child->perf_event_mutex);
9042 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9044 list_del_init(&event->owner_entry);
9047 * Ensure the list deletion is visible before we clear
9048 * the owner, closes a race against perf_release() where
9049 * we need to serialize on the owner->perf_event_mutex.
9052 event->owner = NULL;
9054 mutex_unlock(&child->perf_event_mutex);
9056 for_each_task_context_nr(ctxn)
9057 perf_event_exit_task_context(child, ctxn);
9060 * The perf_event_exit_task_context calls perf_event_task
9061 * with child's task_ctx, which generates EXIT events for
9062 * child contexts and sets child->perf_event_ctxp[] to NULL.
9063 * At this point we need to send EXIT events to cpu contexts.
9065 perf_event_task(child, NULL, 0);
9068 static void perf_free_event(struct perf_event *event,
9069 struct perf_event_context *ctx)
9071 struct perf_event *parent = event->parent;
9073 if (WARN_ON_ONCE(!parent))
9076 mutex_lock(&parent->child_mutex);
9077 list_del_init(&event->child_list);
9078 mutex_unlock(&parent->child_mutex);
9082 raw_spin_lock_irq(&ctx->lock);
9083 perf_group_detach(event);
9084 list_del_event(event, ctx);
9085 raw_spin_unlock_irq(&ctx->lock);
9090 * Free an unexposed, unused context as created by inheritance by
9091 * perf_event_init_task below, used by fork() in case of fail.
9093 * Not all locks are strictly required, but take them anyway to be nice and
9094 * help out with the lockdep assertions.
9096 void perf_event_free_task(struct task_struct *task)
9098 struct perf_event_context *ctx;
9099 struct perf_event *event, *tmp;
9102 for_each_task_context_nr(ctxn) {
9103 ctx = task->perf_event_ctxp[ctxn];
9107 mutex_lock(&ctx->mutex);
9109 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9111 perf_free_event(event, ctx);
9113 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9115 perf_free_event(event, ctx);
9117 if (!list_empty(&ctx->pinned_groups) ||
9118 !list_empty(&ctx->flexible_groups))
9121 mutex_unlock(&ctx->mutex);
9127 void perf_event_delayed_put(struct task_struct *task)
9131 for_each_task_context_nr(ctxn)
9132 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9135 struct perf_event *perf_event_get(unsigned int fd)
9139 struct perf_event *event;
9141 err = perf_fget_light(fd, &f);
9143 return ERR_PTR(err);
9145 event = f.file->private_data;
9146 atomic_long_inc(&event->refcount);
9152 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9155 return ERR_PTR(-EINVAL);
9157 return &event->attr;
9161 * inherit a event from parent task to child task:
9163 static struct perf_event *
9164 inherit_event(struct perf_event *parent_event,
9165 struct task_struct *parent,
9166 struct perf_event_context *parent_ctx,
9167 struct task_struct *child,
9168 struct perf_event *group_leader,
9169 struct perf_event_context *child_ctx)
9171 enum perf_event_active_state parent_state = parent_event->state;
9172 struct perf_event *child_event;
9173 unsigned long flags;
9176 * Instead of creating recursive hierarchies of events,
9177 * we link inherited events back to the original parent,
9178 * which has a filp for sure, which we use as the reference
9181 if (parent_event->parent)
9182 parent_event = parent_event->parent;
9184 child_event = perf_event_alloc(&parent_event->attr,
9187 group_leader, parent_event,
9189 if (IS_ERR(child_event))
9192 if (is_orphaned_event(parent_event) ||
9193 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9194 free_event(child_event);
9201 * Make the child state follow the state of the parent event,
9202 * not its attr.disabled bit. We hold the parent's mutex,
9203 * so we won't race with perf_event_{en, dis}able_family.
9205 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9206 child_event->state = PERF_EVENT_STATE_INACTIVE;
9208 child_event->state = PERF_EVENT_STATE_OFF;
9210 if (parent_event->attr.freq) {
9211 u64 sample_period = parent_event->hw.sample_period;
9212 struct hw_perf_event *hwc = &child_event->hw;
9214 hwc->sample_period = sample_period;
9215 hwc->last_period = sample_period;
9217 local64_set(&hwc->period_left, sample_period);
9220 child_event->ctx = child_ctx;
9221 child_event->overflow_handler = parent_event->overflow_handler;
9222 child_event->overflow_handler_context
9223 = parent_event->overflow_handler_context;
9226 * Precalculate sample_data sizes
9228 perf_event__header_size(child_event);
9229 perf_event__id_header_size(child_event);
9232 * Link it up in the child's context:
9234 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9235 add_event_to_ctx(child_event, child_ctx);
9236 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9239 * Link this into the parent event's child list
9241 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9242 mutex_lock(&parent_event->child_mutex);
9243 list_add_tail(&child_event->child_list, &parent_event->child_list);
9244 mutex_unlock(&parent_event->child_mutex);
9249 static int inherit_group(struct perf_event *parent_event,
9250 struct task_struct *parent,
9251 struct perf_event_context *parent_ctx,
9252 struct task_struct *child,
9253 struct perf_event_context *child_ctx)
9255 struct perf_event *leader;
9256 struct perf_event *sub;
9257 struct perf_event *child_ctr;
9259 leader = inherit_event(parent_event, parent, parent_ctx,
9260 child, NULL, child_ctx);
9262 return PTR_ERR(leader);
9263 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9264 child_ctr = inherit_event(sub, parent, parent_ctx,
9265 child, leader, child_ctx);
9266 if (IS_ERR(child_ctr))
9267 return PTR_ERR(child_ctr);
9273 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9274 struct perf_event_context *parent_ctx,
9275 struct task_struct *child, int ctxn,
9279 struct perf_event_context *child_ctx;
9281 if (!event->attr.inherit) {
9286 child_ctx = child->perf_event_ctxp[ctxn];
9289 * This is executed from the parent task context, so
9290 * inherit events that have been marked for cloning.
9291 * First allocate and initialize a context for the
9295 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9299 child->perf_event_ctxp[ctxn] = child_ctx;
9302 ret = inherit_group(event, parent, parent_ctx,
9312 * Initialize the perf_event context in task_struct
9314 static int perf_event_init_context(struct task_struct *child, int ctxn)
9316 struct perf_event_context *child_ctx, *parent_ctx;
9317 struct perf_event_context *cloned_ctx;
9318 struct perf_event *event;
9319 struct task_struct *parent = current;
9320 int inherited_all = 1;
9321 unsigned long flags;
9324 if (likely(!parent->perf_event_ctxp[ctxn]))
9328 * If the parent's context is a clone, pin it so it won't get
9331 parent_ctx = perf_pin_task_context(parent, ctxn);
9336 * No need to check if parent_ctx != NULL here; since we saw
9337 * it non-NULL earlier, the only reason for it to become NULL
9338 * is if we exit, and since we're currently in the middle of
9339 * a fork we can't be exiting at the same time.
9343 * Lock the parent list. No need to lock the child - not PID
9344 * hashed yet and not running, so nobody can access it.
9346 mutex_lock(&parent_ctx->mutex);
9349 * We dont have to disable NMIs - we are only looking at
9350 * the list, not manipulating it:
9352 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9353 ret = inherit_task_group(event, parent, parent_ctx,
9354 child, ctxn, &inherited_all);
9360 * We can't hold ctx->lock when iterating the ->flexible_group list due
9361 * to allocations, but we need to prevent rotation because
9362 * rotate_ctx() will change the list from interrupt context.
9364 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9365 parent_ctx->rotate_disable = 1;
9366 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9368 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9369 ret = inherit_task_group(event, parent, parent_ctx,
9370 child, ctxn, &inherited_all);
9375 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9376 parent_ctx->rotate_disable = 0;
9378 child_ctx = child->perf_event_ctxp[ctxn];
9380 if (child_ctx && inherited_all) {
9382 * Mark the child context as a clone of the parent
9383 * context, or of whatever the parent is a clone of.
9385 * Note that if the parent is a clone, the holding of
9386 * parent_ctx->lock avoids it from being uncloned.
9388 cloned_ctx = parent_ctx->parent_ctx;
9390 child_ctx->parent_ctx = cloned_ctx;
9391 child_ctx->parent_gen = parent_ctx->parent_gen;
9393 child_ctx->parent_ctx = parent_ctx;
9394 child_ctx->parent_gen = parent_ctx->generation;
9396 get_ctx(child_ctx->parent_ctx);
9399 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9400 mutex_unlock(&parent_ctx->mutex);
9402 perf_unpin_context(parent_ctx);
9403 put_ctx(parent_ctx);
9409 * Initialize the perf_event context in task_struct
9411 int perf_event_init_task(struct task_struct *child)
9415 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9416 mutex_init(&child->perf_event_mutex);
9417 INIT_LIST_HEAD(&child->perf_event_list);
9419 for_each_task_context_nr(ctxn) {
9420 ret = perf_event_init_context(child, ctxn);
9422 perf_event_free_task(child);
9430 static void __init perf_event_init_all_cpus(void)
9432 struct swevent_htable *swhash;
9435 for_each_possible_cpu(cpu) {
9436 swhash = &per_cpu(swevent_htable, cpu);
9437 mutex_init(&swhash->hlist_mutex);
9438 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9442 static void perf_event_init_cpu(int cpu)
9444 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9446 mutex_lock(&swhash->hlist_mutex);
9447 if (swhash->hlist_refcount > 0) {
9448 struct swevent_hlist *hlist;
9450 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9452 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9454 mutex_unlock(&swhash->hlist_mutex);
9457 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9458 static void __perf_event_exit_context(void *__info)
9460 struct remove_event re = { .detach_group = true };
9461 struct perf_event_context *ctx = __info;
9464 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9465 __perf_remove_from_context(&re);
9469 static void perf_event_exit_cpu_context(int cpu)
9471 struct perf_event_context *ctx;
9475 idx = srcu_read_lock(&pmus_srcu);
9476 list_for_each_entry_rcu(pmu, &pmus, entry) {
9477 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9479 mutex_lock(&ctx->mutex);
9480 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9481 mutex_unlock(&ctx->mutex);
9483 srcu_read_unlock(&pmus_srcu, idx);
9486 static void perf_event_exit_cpu(int cpu)
9488 perf_event_exit_cpu_context(cpu);
9491 static inline void perf_event_exit_cpu(int cpu) { }
9495 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9499 for_each_online_cpu(cpu)
9500 perf_event_exit_cpu(cpu);
9506 * Run the perf reboot notifier at the very last possible moment so that
9507 * the generic watchdog code runs as long as possible.
9509 static struct notifier_block perf_reboot_notifier = {
9510 .notifier_call = perf_reboot,
9511 .priority = INT_MIN,
9515 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9517 unsigned int cpu = (long)hcpu;
9519 switch (action & ~CPU_TASKS_FROZEN) {
9521 case CPU_UP_PREPARE:
9522 case CPU_DOWN_FAILED:
9523 perf_event_init_cpu(cpu);
9526 case CPU_UP_CANCELED:
9527 case CPU_DOWN_PREPARE:
9528 perf_event_exit_cpu(cpu);
9537 void __init perf_event_init(void)
9543 perf_event_init_all_cpus();
9544 init_srcu_struct(&pmus_srcu);
9545 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9546 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9547 perf_pmu_register(&perf_task_clock, NULL, -1);
9549 perf_cpu_notifier(perf_cpu_notify);
9550 register_reboot_notifier(&perf_reboot_notifier);
9552 ret = init_hw_breakpoint();
9553 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9555 /* do not patch jump label more than once per second */
9556 jump_label_rate_limit(&perf_sched_events, HZ);
9559 * Build time assertion that we keep the data_head at the intended
9560 * location. IOW, validation we got the __reserved[] size right.
9562 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9566 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9569 struct perf_pmu_events_attr *pmu_attr =
9570 container_of(attr, struct perf_pmu_events_attr, attr);
9572 if (pmu_attr->event_str)
9573 return sprintf(page, "%s\n", pmu_attr->event_str);
9578 static int __init perf_event_sysfs_init(void)
9583 mutex_lock(&pmus_lock);
9585 ret = bus_register(&pmu_bus);
9589 list_for_each_entry(pmu, &pmus, entry) {
9590 if (!pmu->name || pmu->type < 0)
9593 ret = pmu_dev_alloc(pmu);
9594 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9596 pmu_bus_running = 1;
9600 mutex_unlock(&pmus_lock);
9604 device_initcall(perf_event_sysfs_init);
9606 #ifdef CONFIG_CGROUP_PERF
9607 static struct cgroup_subsys_state *
9608 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9610 struct perf_cgroup *jc;
9612 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9614 return ERR_PTR(-ENOMEM);
9616 jc->info = alloc_percpu(struct perf_cgroup_info);
9619 return ERR_PTR(-ENOMEM);
9625 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9627 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9629 free_percpu(jc->info);
9633 static int __perf_cgroup_move(void *info)
9635 struct task_struct *task = info;
9637 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9642 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9644 struct task_struct *task;
9645 struct cgroup_subsys_state *css;
9647 cgroup_taskset_for_each(task, css, tset)
9648 task_function_call(task, __perf_cgroup_move, task);
9651 struct cgroup_subsys perf_event_cgrp_subsys = {
9652 .css_alloc = perf_cgroup_css_alloc,
9653 .css_free = perf_cgroup_css_free,
9654 .attach = perf_cgroup_attach,
9656 #endif /* CONFIG_CGROUP_PERF */