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 <pzijlstr@redhat.com>
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
179 int sysctl_perf_event_paranoid __read_mostly = 1;
181 /* Minimum for 512 kiB + 1 user control page */
182 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
185 * max perf event sample rate
187 #define DEFAULT_MAX_SAMPLE_RATE 100000
188 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
189 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
191 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
193 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
194 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
196 static int perf_sample_allowed_ns __read_mostly =
197 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
199 void update_perf_cpu_limits(void)
201 u64 tmp = perf_sample_period_ns;
203 tmp *= sysctl_perf_cpu_time_max_percent;
205 ACCESS_ONCE(perf_sample_allowed_ns) = tmp;
208 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
210 int perf_proc_update_handler(struct ctl_table *table, int write,
211 void __user *buffer, size_t *lenp,
214 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
219 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
220 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
221 update_perf_cpu_limits();
226 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
228 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
229 void __user *buffer, size_t *lenp,
232 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
237 update_perf_cpu_limits();
243 * perf samples are done in some very critical code paths (NMIs).
244 * If they take too much CPU time, the system can lock up and not
245 * get any real work done. This will drop the sample rate when
246 * we detect that events are taking too long.
248 #define NR_ACCUMULATED_SAMPLES 128
249 static DEFINE_PER_CPU(u64, running_sample_length);
251 static void perf_duration_warn(struct irq_work *w)
253 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
254 u64 avg_local_sample_len;
255 u64 local_samples_len;
257 local_samples_len = __this_cpu_read(running_sample_length);
258 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
260 printk_ratelimited(KERN_WARNING
261 "perf interrupt took too long (%lld > %lld), lowering "
262 "kernel.perf_event_max_sample_rate to %d\n",
263 avg_local_sample_len, allowed_ns >> 1,
264 sysctl_perf_event_sample_rate);
267 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
269 void perf_sample_event_took(u64 sample_len_ns)
271 u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns);
272 u64 avg_local_sample_len;
273 u64 local_samples_len;
278 /* decay the counter by 1 average sample */
279 local_samples_len = __this_cpu_read(running_sample_length);
280 local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
281 local_samples_len += sample_len_ns;
282 __this_cpu_write(running_sample_length, local_samples_len);
285 * note: this will be biased artifically low until we have
286 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
287 * from having to maintain a count.
289 avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
291 if (avg_local_sample_len <= allowed_ns)
294 if (max_samples_per_tick <= 1)
297 max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
298 sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
299 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
301 update_perf_cpu_limits();
303 if (!irq_work_queue(&perf_duration_work)) {
304 early_printk("perf interrupt took too long (%lld > %lld), lowering "
305 "kernel.perf_event_max_sample_rate to %d\n",
306 avg_local_sample_len, allowed_ns >> 1,
307 sysctl_perf_event_sample_rate);
311 static atomic64_t perf_event_id;
313 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
314 enum event_type_t event_type);
316 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
317 enum event_type_t event_type,
318 struct task_struct *task);
320 static void update_context_time(struct perf_event_context *ctx);
321 static u64 perf_event_time(struct perf_event *event);
323 void __weak perf_event_print_debug(void) { }
325 extern __weak const char *perf_pmu_name(void)
330 static inline u64 perf_clock(void)
332 return local_clock();
335 static inline u64 perf_event_clock(struct perf_event *event)
337 return event->clock();
340 static inline struct perf_cpu_context *
341 __get_cpu_context(struct perf_event_context *ctx)
343 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
346 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
347 struct perf_event_context *ctx)
349 raw_spin_lock(&cpuctx->ctx.lock);
351 raw_spin_lock(&ctx->lock);
354 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
355 struct perf_event_context *ctx)
358 raw_spin_unlock(&ctx->lock);
359 raw_spin_unlock(&cpuctx->ctx.lock);
362 #ifdef CONFIG_CGROUP_PERF
365 perf_cgroup_match(struct perf_event *event)
367 struct perf_event_context *ctx = event->ctx;
368 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
370 /* @event doesn't care about cgroup */
374 /* wants specific cgroup scope but @cpuctx isn't associated with any */
379 * Cgroup scoping is recursive. An event enabled for a cgroup is
380 * also enabled for all its descendant cgroups. If @cpuctx's
381 * cgroup is a descendant of @event's (the test covers identity
382 * case), it's a match.
384 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
385 event->cgrp->css.cgroup);
388 static inline void perf_detach_cgroup(struct perf_event *event)
390 css_put(&event->cgrp->css);
394 static inline int is_cgroup_event(struct perf_event *event)
396 return event->cgrp != NULL;
399 static inline u64 perf_cgroup_event_time(struct perf_event *event)
401 struct perf_cgroup_info *t;
403 t = per_cpu_ptr(event->cgrp->info, event->cpu);
407 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
409 struct perf_cgroup_info *info;
414 info = this_cpu_ptr(cgrp->info);
416 info->time += now - info->timestamp;
417 info->timestamp = now;
420 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
422 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
424 __update_cgrp_time(cgrp_out);
427 static inline void update_cgrp_time_from_event(struct perf_event *event)
429 struct perf_cgroup *cgrp;
432 * ensure we access cgroup data only when needed and
433 * when we know the cgroup is pinned (css_get)
435 if (!is_cgroup_event(event))
438 cgrp = perf_cgroup_from_task(current);
440 * Do not update time when cgroup is not active
442 if (cgrp == event->cgrp)
443 __update_cgrp_time(event->cgrp);
447 perf_cgroup_set_timestamp(struct task_struct *task,
448 struct perf_event_context *ctx)
450 struct perf_cgroup *cgrp;
451 struct perf_cgroup_info *info;
454 * ctx->lock held by caller
455 * ensure we do not access cgroup data
456 * unless we have the cgroup pinned (css_get)
458 if (!task || !ctx->nr_cgroups)
461 cgrp = perf_cgroup_from_task(task);
462 info = this_cpu_ptr(cgrp->info);
463 info->timestamp = ctx->timestamp;
466 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
467 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
470 * reschedule events based on the cgroup constraint of task.
472 * mode SWOUT : schedule out everything
473 * mode SWIN : schedule in based on cgroup for next
475 void perf_cgroup_switch(struct task_struct *task, int mode)
477 struct perf_cpu_context *cpuctx;
482 * disable interrupts to avoid geting nr_cgroup
483 * changes via __perf_event_disable(). Also
486 local_irq_save(flags);
489 * we reschedule only in the presence of cgroup
490 * constrained events.
494 list_for_each_entry_rcu(pmu, &pmus, entry) {
495 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
496 if (cpuctx->unique_pmu != pmu)
497 continue; /* ensure we process each cpuctx once */
500 * perf_cgroup_events says at least one
501 * context on this CPU has cgroup events.
503 * ctx->nr_cgroups reports the number of cgroup
504 * events for a context.
506 if (cpuctx->ctx.nr_cgroups > 0) {
507 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
508 perf_pmu_disable(cpuctx->ctx.pmu);
510 if (mode & PERF_CGROUP_SWOUT) {
511 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
513 * must not be done before ctxswout due
514 * to event_filter_match() in event_sched_out()
519 if (mode & PERF_CGROUP_SWIN) {
520 WARN_ON_ONCE(cpuctx->cgrp);
522 * set cgrp before ctxsw in to allow
523 * event_filter_match() to not have to pass
526 cpuctx->cgrp = perf_cgroup_from_task(task);
527 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
529 perf_pmu_enable(cpuctx->ctx.pmu);
530 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
536 local_irq_restore(flags);
539 static inline void perf_cgroup_sched_out(struct task_struct *task,
540 struct task_struct *next)
542 struct perf_cgroup *cgrp1;
543 struct perf_cgroup *cgrp2 = NULL;
546 * we come here when we know perf_cgroup_events > 0
548 cgrp1 = perf_cgroup_from_task(task);
551 * next is NULL when called from perf_event_enable_on_exec()
552 * that will systematically cause a cgroup_switch()
555 cgrp2 = perf_cgroup_from_task(next);
558 * only schedule out current cgroup events if we know
559 * that we are switching to a different cgroup. Otherwise,
560 * do no touch the cgroup events.
563 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
566 static inline void perf_cgroup_sched_in(struct task_struct *prev,
567 struct task_struct *task)
569 struct perf_cgroup *cgrp1;
570 struct perf_cgroup *cgrp2 = NULL;
573 * we come here when we know perf_cgroup_events > 0
575 cgrp1 = perf_cgroup_from_task(task);
577 /* prev can never be NULL */
578 cgrp2 = perf_cgroup_from_task(prev);
581 * only need to schedule in cgroup events if we are changing
582 * cgroup during ctxsw. Cgroup events were not scheduled
583 * out of ctxsw out if that was not the case.
586 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
589 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
590 struct perf_event_attr *attr,
591 struct perf_event *group_leader)
593 struct perf_cgroup *cgrp;
594 struct cgroup_subsys_state *css;
595 struct fd f = fdget(fd);
601 css = css_tryget_online_from_dir(f.file->f_path.dentry,
602 &perf_event_cgrp_subsys);
608 cgrp = container_of(css, struct perf_cgroup, css);
612 * all events in a group must monitor
613 * the same cgroup because a task belongs
614 * to only one perf cgroup at a time
616 if (group_leader && group_leader->cgrp != cgrp) {
617 perf_detach_cgroup(event);
626 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
628 struct perf_cgroup_info *t;
629 t = per_cpu_ptr(event->cgrp->info, event->cpu);
630 event->shadow_ctx_time = now - t->timestamp;
634 perf_cgroup_defer_enabled(struct perf_event *event)
637 * when the current task's perf cgroup does not match
638 * the event's, we need to remember to call the
639 * perf_mark_enable() function the first time a task with
640 * a matching perf cgroup is scheduled in.
642 if (is_cgroup_event(event) && !perf_cgroup_match(event))
643 event->cgrp_defer_enabled = 1;
647 perf_cgroup_mark_enabled(struct perf_event *event,
648 struct perf_event_context *ctx)
650 struct perf_event *sub;
651 u64 tstamp = perf_event_time(event);
653 if (!event->cgrp_defer_enabled)
656 event->cgrp_defer_enabled = 0;
658 event->tstamp_enabled = tstamp - event->total_time_enabled;
659 list_for_each_entry(sub, &event->sibling_list, group_entry) {
660 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
661 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
662 sub->cgrp_defer_enabled = 0;
666 #else /* !CONFIG_CGROUP_PERF */
669 perf_cgroup_match(struct perf_event *event)
674 static inline void perf_detach_cgroup(struct perf_event *event)
677 static inline int is_cgroup_event(struct perf_event *event)
682 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
687 static inline void update_cgrp_time_from_event(struct perf_event *event)
691 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
695 static inline void perf_cgroup_sched_out(struct task_struct *task,
696 struct task_struct *next)
700 static inline void perf_cgroup_sched_in(struct task_struct *prev,
701 struct task_struct *task)
705 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
706 struct perf_event_attr *attr,
707 struct perf_event *group_leader)
713 perf_cgroup_set_timestamp(struct task_struct *task,
714 struct perf_event_context *ctx)
719 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
724 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
728 static inline u64 perf_cgroup_event_time(struct perf_event *event)
734 perf_cgroup_defer_enabled(struct perf_event *event)
739 perf_cgroup_mark_enabled(struct perf_event *event,
740 struct perf_event_context *ctx)
746 * set default to be dependent on timer tick just
749 #define PERF_CPU_HRTIMER (1000 / HZ)
751 * function must be called with interrupts disbled
753 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
755 struct perf_cpu_context *cpuctx;
758 WARN_ON(!irqs_disabled());
760 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
761 rotations = perf_rotate_context(cpuctx);
763 raw_spin_lock(&cpuctx->hrtimer_lock);
765 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
767 cpuctx->hrtimer_active = 0;
768 raw_spin_unlock(&cpuctx->hrtimer_lock);
770 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
773 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
775 struct hrtimer *timer = &cpuctx->hrtimer;
776 struct pmu *pmu = cpuctx->ctx.pmu;
779 /* no multiplexing needed for SW PMU */
780 if (pmu->task_ctx_nr == perf_sw_context)
784 * check default is sane, if not set then force to
785 * default interval (1/tick)
787 interval = pmu->hrtimer_interval_ms;
789 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
791 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
793 raw_spin_lock_init(&cpuctx->hrtimer_lock);
794 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
795 timer->function = perf_mux_hrtimer_handler;
798 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
800 struct hrtimer *timer = &cpuctx->hrtimer;
801 struct pmu *pmu = cpuctx->ctx.pmu;
805 if (pmu->task_ctx_nr == perf_sw_context)
808 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
809 if (!cpuctx->hrtimer_active) {
810 cpuctx->hrtimer_active = 1;
811 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
812 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
814 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
819 void perf_pmu_disable(struct pmu *pmu)
821 int *count = this_cpu_ptr(pmu->pmu_disable_count);
823 pmu->pmu_disable(pmu);
826 void perf_pmu_enable(struct pmu *pmu)
828 int *count = this_cpu_ptr(pmu->pmu_disable_count);
830 pmu->pmu_enable(pmu);
833 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
836 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
837 * perf_event_task_tick() are fully serialized because they're strictly cpu
838 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
839 * disabled, while perf_event_task_tick is called from IRQ context.
841 static void perf_event_ctx_activate(struct perf_event_context *ctx)
843 struct list_head *head = this_cpu_ptr(&active_ctx_list);
845 WARN_ON(!irqs_disabled());
847 WARN_ON(!list_empty(&ctx->active_ctx_list));
849 list_add(&ctx->active_ctx_list, head);
852 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
854 WARN_ON(!irqs_disabled());
856 WARN_ON(list_empty(&ctx->active_ctx_list));
858 list_del_init(&ctx->active_ctx_list);
861 static void get_ctx(struct perf_event_context *ctx)
863 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
866 static void free_ctx(struct rcu_head *head)
868 struct perf_event_context *ctx;
870 ctx = container_of(head, struct perf_event_context, rcu_head);
871 kfree(ctx->task_ctx_data);
875 static void put_ctx(struct perf_event_context *ctx)
877 if (atomic_dec_and_test(&ctx->refcount)) {
879 put_ctx(ctx->parent_ctx);
881 put_task_struct(ctx->task);
882 call_rcu(&ctx->rcu_head, free_ctx);
887 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
888 * perf_pmu_migrate_context() we need some magic.
890 * Those places that change perf_event::ctx will hold both
891 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
893 * Lock ordering is by mutex address. There are two other sites where
894 * perf_event_context::mutex nests and those are:
896 * - perf_event_exit_task_context() [ child , 0 ]
897 * __perf_event_exit_task()
899 * put_event() [ parent, 1 ]
901 * - perf_event_init_context() [ parent, 0 ]
902 * inherit_task_group()
907 * perf_try_init_event() [ child , 1 ]
909 * While it appears there is an obvious deadlock here -- the parent and child
910 * nesting levels are inverted between the two. This is in fact safe because
911 * life-time rules separate them. That is an exiting task cannot fork, and a
912 * spawning task cannot (yet) exit.
914 * But remember that that these are parent<->child context relations, and
915 * migration does not affect children, therefore these two orderings should not
918 * The change in perf_event::ctx does not affect children (as claimed above)
919 * because the sys_perf_event_open() case will install a new event and break
920 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
921 * concerned with cpuctx and that doesn't have children.
923 * The places that change perf_event::ctx will issue:
925 * perf_remove_from_context();
927 * perf_install_in_context();
929 * to affect the change. The remove_from_context() + synchronize_rcu() should
930 * quiesce the event, after which we can install it in the new location. This
931 * means that only external vectors (perf_fops, prctl) can perturb the event
932 * while in transit. Therefore all such accessors should also acquire
933 * perf_event_context::mutex to serialize against this.
935 * However; because event->ctx can change while we're waiting to acquire
936 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
940 * task_struct::perf_event_mutex
941 * perf_event_context::mutex
942 * perf_event_context::lock
943 * perf_event::child_mutex;
944 * perf_event::mmap_mutex
947 static struct perf_event_context *
948 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
950 struct perf_event_context *ctx;
954 ctx = ACCESS_ONCE(event->ctx);
955 if (!atomic_inc_not_zero(&ctx->refcount)) {
961 mutex_lock_nested(&ctx->mutex, nesting);
962 if (event->ctx != ctx) {
963 mutex_unlock(&ctx->mutex);
971 static inline struct perf_event_context *
972 perf_event_ctx_lock(struct perf_event *event)
974 return perf_event_ctx_lock_nested(event, 0);
977 static void perf_event_ctx_unlock(struct perf_event *event,
978 struct perf_event_context *ctx)
980 mutex_unlock(&ctx->mutex);
985 * This must be done under the ctx->lock, such as to serialize against
986 * context_equiv(), therefore we cannot call put_ctx() since that might end up
987 * calling scheduler related locks and ctx->lock nests inside those.
989 static __must_check struct perf_event_context *
990 unclone_ctx(struct perf_event_context *ctx)
992 struct perf_event_context *parent_ctx = ctx->parent_ctx;
994 lockdep_assert_held(&ctx->lock);
997 ctx->parent_ctx = NULL;
1003 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1006 * only top level events have the pid namespace they were created in
1009 event = event->parent;
1011 return task_tgid_nr_ns(p, event->ns);
1014 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1017 * only top level events have the pid namespace they were created in
1020 event = event->parent;
1022 return task_pid_nr_ns(p, event->ns);
1026 * If we inherit events we want to return the parent event id
1029 static u64 primary_event_id(struct perf_event *event)
1034 id = event->parent->id;
1040 * Get the perf_event_context for a task and lock it.
1041 * This has to cope with with the fact that until it is locked,
1042 * the context could get moved to another task.
1044 static struct perf_event_context *
1045 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1047 struct perf_event_context *ctx;
1051 * One of the few rules of preemptible RCU is that one cannot do
1052 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1053 * part of the read side critical section was preemptible -- see
1054 * rcu_read_unlock_special().
1056 * Since ctx->lock nests under rq->lock we must ensure the entire read
1057 * side critical section is non-preemptible.
1061 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1064 * If this context is a clone of another, it might
1065 * get swapped for another underneath us by
1066 * perf_event_task_sched_out, though the
1067 * rcu_read_lock() protects us from any context
1068 * getting freed. Lock the context and check if it
1069 * got swapped before we could get the lock, and retry
1070 * if so. If we locked the right context, then it
1071 * can't get swapped on us any more.
1073 raw_spin_lock_irqsave(&ctx->lock, *flags);
1074 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1075 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
1081 if (!atomic_inc_not_zero(&ctx->refcount)) {
1082 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
1092 * Get the context for a task and increment its pin_count so it
1093 * can't get swapped to another task. This also increments its
1094 * reference count so that the context can't get freed.
1096 static struct perf_event_context *
1097 perf_pin_task_context(struct task_struct *task, int ctxn)
1099 struct perf_event_context *ctx;
1100 unsigned long flags;
1102 ctx = perf_lock_task_context(task, ctxn, &flags);
1105 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1110 static void perf_unpin_context(struct perf_event_context *ctx)
1112 unsigned long flags;
1114 raw_spin_lock_irqsave(&ctx->lock, flags);
1116 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1120 * Update the record of the current time in a context.
1122 static void update_context_time(struct perf_event_context *ctx)
1124 u64 now = perf_clock();
1126 ctx->time += now - ctx->timestamp;
1127 ctx->timestamp = now;
1130 static u64 perf_event_time(struct perf_event *event)
1132 struct perf_event_context *ctx = event->ctx;
1134 if (is_cgroup_event(event))
1135 return perf_cgroup_event_time(event);
1137 return ctx ? ctx->time : 0;
1141 * Update the total_time_enabled and total_time_running fields for a event.
1142 * The caller of this function needs to hold the ctx->lock.
1144 static void update_event_times(struct perf_event *event)
1146 struct perf_event_context *ctx = event->ctx;
1149 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1150 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1153 * in cgroup mode, time_enabled represents
1154 * the time the event was enabled AND active
1155 * tasks were in the monitored cgroup. This is
1156 * independent of the activity of the context as
1157 * there may be a mix of cgroup and non-cgroup events.
1159 * That is why we treat cgroup events differently
1162 if (is_cgroup_event(event))
1163 run_end = perf_cgroup_event_time(event);
1164 else if (ctx->is_active)
1165 run_end = ctx->time;
1167 run_end = event->tstamp_stopped;
1169 event->total_time_enabled = run_end - event->tstamp_enabled;
1171 if (event->state == PERF_EVENT_STATE_INACTIVE)
1172 run_end = event->tstamp_stopped;
1174 run_end = perf_event_time(event);
1176 event->total_time_running = run_end - event->tstamp_running;
1181 * Update total_time_enabled and total_time_running for all events in a group.
1183 static void update_group_times(struct perf_event *leader)
1185 struct perf_event *event;
1187 update_event_times(leader);
1188 list_for_each_entry(event, &leader->sibling_list, group_entry)
1189 update_event_times(event);
1192 static struct list_head *
1193 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1195 if (event->attr.pinned)
1196 return &ctx->pinned_groups;
1198 return &ctx->flexible_groups;
1202 * Add a event from the lists for its context.
1203 * Must be called with ctx->mutex and ctx->lock held.
1206 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1208 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1209 event->attach_state |= PERF_ATTACH_CONTEXT;
1212 * If we're a stand alone event or group leader, we go to the context
1213 * list, group events are kept attached to the group so that
1214 * perf_group_detach can, at all times, locate all siblings.
1216 if (event->group_leader == event) {
1217 struct list_head *list;
1219 if (is_software_event(event))
1220 event->group_flags |= PERF_GROUP_SOFTWARE;
1222 list = ctx_group_list(event, ctx);
1223 list_add_tail(&event->group_entry, list);
1226 if (is_cgroup_event(event))
1229 list_add_rcu(&event->event_entry, &ctx->event_list);
1231 if (event->attr.inherit_stat)
1238 * Initialize event state based on the perf_event_attr::disabled.
1240 static inline void perf_event__state_init(struct perf_event *event)
1242 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1243 PERF_EVENT_STATE_INACTIVE;
1246 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1248 int entry = sizeof(u64); /* value */
1252 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1253 size += sizeof(u64);
1255 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1256 size += sizeof(u64);
1258 if (event->attr.read_format & PERF_FORMAT_ID)
1259 entry += sizeof(u64);
1261 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1263 size += sizeof(u64);
1267 event->read_size = size;
1270 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1272 struct perf_sample_data *data;
1275 if (sample_type & PERF_SAMPLE_IP)
1276 size += sizeof(data->ip);
1278 if (sample_type & PERF_SAMPLE_ADDR)
1279 size += sizeof(data->addr);
1281 if (sample_type & PERF_SAMPLE_PERIOD)
1282 size += sizeof(data->period);
1284 if (sample_type & PERF_SAMPLE_WEIGHT)
1285 size += sizeof(data->weight);
1287 if (sample_type & PERF_SAMPLE_READ)
1288 size += event->read_size;
1290 if (sample_type & PERF_SAMPLE_DATA_SRC)
1291 size += sizeof(data->data_src.val);
1293 if (sample_type & PERF_SAMPLE_TRANSACTION)
1294 size += sizeof(data->txn);
1296 event->header_size = size;
1300 * Called at perf_event creation and when events are attached/detached from a
1303 static void perf_event__header_size(struct perf_event *event)
1305 __perf_event_read_size(event,
1306 event->group_leader->nr_siblings);
1307 __perf_event_header_size(event, event->attr.sample_type);
1310 static void perf_event__id_header_size(struct perf_event *event)
1312 struct perf_sample_data *data;
1313 u64 sample_type = event->attr.sample_type;
1316 if (sample_type & PERF_SAMPLE_TID)
1317 size += sizeof(data->tid_entry);
1319 if (sample_type & PERF_SAMPLE_TIME)
1320 size += sizeof(data->time);
1322 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1323 size += sizeof(data->id);
1325 if (sample_type & PERF_SAMPLE_ID)
1326 size += sizeof(data->id);
1328 if (sample_type & PERF_SAMPLE_STREAM_ID)
1329 size += sizeof(data->stream_id);
1331 if (sample_type & PERF_SAMPLE_CPU)
1332 size += sizeof(data->cpu_entry);
1334 event->id_header_size = size;
1337 static bool perf_event_validate_size(struct perf_event *event)
1340 * The values computed here will be over-written when we actually
1343 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1344 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1345 perf_event__id_header_size(event);
1348 * Sum the lot; should not exceed the 64k limit we have on records.
1349 * Conservative limit to allow for callchains and other variable fields.
1351 if (event->read_size + event->header_size +
1352 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1358 static void perf_group_attach(struct perf_event *event)
1360 struct perf_event *group_leader = event->group_leader, *pos;
1363 * We can have double attach due to group movement in perf_event_open.
1365 if (event->attach_state & PERF_ATTACH_GROUP)
1368 event->attach_state |= PERF_ATTACH_GROUP;
1370 if (group_leader == event)
1373 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1375 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1376 !is_software_event(event))
1377 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1379 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1380 group_leader->nr_siblings++;
1382 perf_event__header_size(group_leader);
1384 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1385 perf_event__header_size(pos);
1389 * Remove a event from the lists for its context.
1390 * Must be called with ctx->mutex and ctx->lock held.
1393 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1395 struct perf_cpu_context *cpuctx;
1397 WARN_ON_ONCE(event->ctx != ctx);
1398 lockdep_assert_held(&ctx->lock);
1401 * We can have double detach due to exit/hot-unplug + close.
1403 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1406 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1408 if (is_cgroup_event(event)) {
1410 cpuctx = __get_cpu_context(ctx);
1412 * if there are no more cgroup events
1413 * then cler cgrp to avoid stale pointer
1414 * in update_cgrp_time_from_cpuctx()
1416 if (!ctx->nr_cgroups)
1417 cpuctx->cgrp = NULL;
1421 if (event->attr.inherit_stat)
1424 list_del_rcu(&event->event_entry);
1426 if (event->group_leader == event)
1427 list_del_init(&event->group_entry);
1429 update_group_times(event);
1432 * If event was in error state, then keep it
1433 * that way, otherwise bogus counts will be
1434 * returned on read(). The only way to get out
1435 * of error state is by explicit re-enabling
1438 if (event->state > PERF_EVENT_STATE_OFF)
1439 event->state = PERF_EVENT_STATE_OFF;
1444 static void perf_group_detach(struct perf_event *event)
1446 struct perf_event *sibling, *tmp;
1447 struct list_head *list = NULL;
1450 * We can have double detach due to exit/hot-unplug + close.
1452 if (!(event->attach_state & PERF_ATTACH_GROUP))
1455 event->attach_state &= ~PERF_ATTACH_GROUP;
1458 * If this is a sibling, remove it from its group.
1460 if (event->group_leader != event) {
1461 list_del_init(&event->group_entry);
1462 event->group_leader->nr_siblings--;
1466 if (!list_empty(&event->group_entry))
1467 list = &event->group_entry;
1470 * If this was a group event with sibling events then
1471 * upgrade the siblings to singleton events by adding them
1472 * to whatever list we are on.
1474 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1476 list_move_tail(&sibling->group_entry, list);
1477 sibling->group_leader = sibling;
1479 /* Inherit group flags from the previous leader */
1480 sibling->group_flags = event->group_flags;
1482 WARN_ON_ONCE(sibling->ctx != event->ctx);
1486 perf_event__header_size(event->group_leader);
1488 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1489 perf_event__header_size(tmp);
1493 * User event without the task.
1495 static bool is_orphaned_event(struct perf_event *event)
1497 return event && !is_kernel_event(event) && !event->owner;
1501 * Event has a parent but parent's task finished and it's
1502 * alive only because of children holding refference.
1504 static bool is_orphaned_child(struct perf_event *event)
1506 return is_orphaned_event(event->parent);
1509 static void orphans_remove_work(struct work_struct *work);
1511 static void schedule_orphans_remove(struct perf_event_context *ctx)
1513 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1516 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1518 ctx->orphans_remove_sched = true;
1522 static int __init perf_workqueue_init(void)
1524 perf_wq = create_singlethread_workqueue("perf");
1525 WARN(!perf_wq, "failed to create perf workqueue\n");
1526 return perf_wq ? 0 : -1;
1529 core_initcall(perf_workqueue_init);
1531 static inline int pmu_filter_match(struct perf_event *event)
1533 struct pmu *pmu = event->pmu;
1534 return pmu->filter_match ? pmu->filter_match(event) : 1;
1538 event_filter_match(struct perf_event *event)
1540 return (event->cpu == -1 || event->cpu == smp_processor_id())
1541 && perf_cgroup_match(event) && pmu_filter_match(event);
1545 event_sched_out(struct perf_event *event,
1546 struct perf_cpu_context *cpuctx,
1547 struct perf_event_context *ctx)
1549 u64 tstamp = perf_event_time(event);
1552 WARN_ON_ONCE(event->ctx != ctx);
1553 lockdep_assert_held(&ctx->lock);
1556 * An event which could not be activated because of
1557 * filter mismatch still needs to have its timings
1558 * maintained, otherwise bogus information is return
1559 * via read() for time_enabled, time_running:
1561 if (event->state == PERF_EVENT_STATE_INACTIVE
1562 && !event_filter_match(event)) {
1563 delta = tstamp - event->tstamp_stopped;
1564 event->tstamp_running += delta;
1565 event->tstamp_stopped = tstamp;
1568 if (event->state != PERF_EVENT_STATE_ACTIVE)
1571 perf_pmu_disable(event->pmu);
1573 event->state = PERF_EVENT_STATE_INACTIVE;
1574 if (event->pending_disable) {
1575 event->pending_disable = 0;
1576 event->state = PERF_EVENT_STATE_OFF;
1578 event->tstamp_stopped = tstamp;
1579 event->pmu->del(event, 0);
1582 if (!is_software_event(event))
1583 cpuctx->active_oncpu--;
1584 if (!--ctx->nr_active)
1585 perf_event_ctx_deactivate(ctx);
1586 if (event->attr.freq && event->attr.sample_freq)
1588 if (event->attr.exclusive || !cpuctx->active_oncpu)
1589 cpuctx->exclusive = 0;
1591 if (is_orphaned_child(event))
1592 schedule_orphans_remove(ctx);
1594 perf_pmu_enable(event->pmu);
1598 group_sched_out(struct perf_event *group_event,
1599 struct perf_cpu_context *cpuctx,
1600 struct perf_event_context *ctx)
1602 struct perf_event *event;
1603 int state = group_event->state;
1605 event_sched_out(group_event, cpuctx, ctx);
1608 * Schedule out siblings (if any):
1610 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1611 event_sched_out(event, cpuctx, ctx);
1613 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1614 cpuctx->exclusive = 0;
1617 struct remove_event {
1618 struct perf_event *event;
1623 * Cross CPU call to remove a performance event
1625 * We disable the event on the hardware level first. After that we
1626 * remove it from the context list.
1628 static int __perf_remove_from_context(void *info)
1630 struct remove_event *re = info;
1631 struct perf_event *event = re->event;
1632 struct perf_event_context *ctx = event->ctx;
1633 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1635 raw_spin_lock(&ctx->lock);
1636 event_sched_out(event, cpuctx, ctx);
1637 if (re->detach_group)
1638 perf_group_detach(event);
1639 list_del_event(event, ctx);
1640 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1642 cpuctx->task_ctx = NULL;
1644 raw_spin_unlock(&ctx->lock);
1651 * Remove the event from a task's (or a CPU's) list of events.
1653 * CPU events are removed with a smp call. For task events we only
1654 * call when the task is on a CPU.
1656 * If event->ctx is a cloned context, callers must make sure that
1657 * every task struct that event->ctx->task could possibly point to
1658 * remains valid. This is OK when called from perf_release since
1659 * that only calls us on the top-level context, which can't be a clone.
1660 * When called from perf_event_exit_task, it's OK because the
1661 * context has been detached from its task.
1663 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1665 struct perf_event_context *ctx = event->ctx;
1666 struct task_struct *task = ctx->task;
1667 struct remove_event re = {
1669 .detach_group = detach_group,
1672 lockdep_assert_held(&ctx->mutex);
1676 * Per cpu events are removed via an smp call. The removal can
1677 * fail if the CPU is currently offline, but in that case we
1678 * already called __perf_remove_from_context from
1679 * perf_event_exit_cpu.
1681 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1686 if (!task_function_call(task, __perf_remove_from_context, &re))
1689 raw_spin_lock_irq(&ctx->lock);
1691 * If we failed to find a running task, but find the context active now
1692 * that we've acquired the ctx->lock, retry.
1694 if (ctx->is_active) {
1695 raw_spin_unlock_irq(&ctx->lock);
1697 * Reload the task pointer, it might have been changed by
1698 * a concurrent perf_event_context_sched_out().
1705 * Since the task isn't running, its safe to remove the event, us
1706 * holding the ctx->lock ensures the task won't get scheduled in.
1709 perf_group_detach(event);
1710 list_del_event(event, ctx);
1711 raw_spin_unlock_irq(&ctx->lock);
1715 * Cross CPU call to disable a performance event
1717 int __perf_event_disable(void *info)
1719 struct perf_event *event = info;
1720 struct perf_event_context *ctx = event->ctx;
1721 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1724 * If this is a per-task event, need to check whether this
1725 * event's task is the current task on this cpu.
1727 * Can trigger due to concurrent perf_event_context_sched_out()
1728 * flipping contexts around.
1730 if (ctx->task && cpuctx->task_ctx != ctx)
1733 raw_spin_lock(&ctx->lock);
1736 * If the event is on, turn it off.
1737 * If it is in error state, leave it in error state.
1739 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1740 update_context_time(ctx);
1741 update_cgrp_time_from_event(event);
1742 update_group_times(event);
1743 if (event == event->group_leader)
1744 group_sched_out(event, cpuctx, ctx);
1746 event_sched_out(event, cpuctx, ctx);
1747 event->state = PERF_EVENT_STATE_OFF;
1750 raw_spin_unlock(&ctx->lock);
1758 * If event->ctx is a cloned context, callers must make sure that
1759 * every task struct that event->ctx->task could possibly point to
1760 * remains valid. This condition is satisifed when called through
1761 * perf_event_for_each_child or perf_event_for_each because they
1762 * hold the top-level event's child_mutex, so any descendant that
1763 * goes to exit will block in sync_child_event.
1764 * When called from perf_pending_event it's OK because event->ctx
1765 * is the current context on this CPU and preemption is disabled,
1766 * hence we can't get into perf_event_task_sched_out for this context.
1768 static void _perf_event_disable(struct perf_event *event)
1770 struct perf_event_context *ctx = event->ctx;
1771 struct task_struct *task = ctx->task;
1775 * Disable the event on the cpu that it's on
1777 cpu_function_call(event->cpu, __perf_event_disable, event);
1782 if (!task_function_call(task, __perf_event_disable, event))
1785 raw_spin_lock_irq(&ctx->lock);
1787 * If the event is still active, we need to retry the cross-call.
1789 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1790 raw_spin_unlock_irq(&ctx->lock);
1792 * Reload the task pointer, it might have been changed by
1793 * a concurrent perf_event_context_sched_out().
1800 * Since we have the lock this context can't be scheduled
1801 * in, so we can change the state safely.
1803 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1804 update_group_times(event);
1805 event->state = PERF_EVENT_STATE_OFF;
1807 raw_spin_unlock_irq(&ctx->lock);
1811 * Strictly speaking kernel users cannot create groups and therefore this
1812 * interface does not need the perf_event_ctx_lock() magic.
1814 void perf_event_disable(struct perf_event *event)
1816 struct perf_event_context *ctx;
1818 ctx = perf_event_ctx_lock(event);
1819 _perf_event_disable(event);
1820 perf_event_ctx_unlock(event, ctx);
1822 EXPORT_SYMBOL_GPL(perf_event_disable);
1824 static void perf_set_shadow_time(struct perf_event *event,
1825 struct perf_event_context *ctx,
1829 * use the correct time source for the time snapshot
1831 * We could get by without this by leveraging the
1832 * fact that to get to this function, the caller
1833 * has most likely already called update_context_time()
1834 * and update_cgrp_time_xx() and thus both timestamp
1835 * are identical (or very close). Given that tstamp is,
1836 * already adjusted for cgroup, we could say that:
1837 * tstamp - ctx->timestamp
1839 * tstamp - cgrp->timestamp.
1841 * Then, in perf_output_read(), the calculation would
1842 * work with no changes because:
1843 * - event is guaranteed scheduled in
1844 * - no scheduled out in between
1845 * - thus the timestamp would be the same
1847 * But this is a bit hairy.
1849 * So instead, we have an explicit cgroup call to remain
1850 * within the time time source all along. We believe it
1851 * is cleaner and simpler to understand.
1853 if (is_cgroup_event(event))
1854 perf_cgroup_set_shadow_time(event, tstamp);
1856 event->shadow_ctx_time = tstamp - ctx->timestamp;
1859 #define MAX_INTERRUPTS (~0ULL)
1861 static void perf_log_throttle(struct perf_event *event, int enable);
1862 static void perf_log_itrace_start(struct perf_event *event);
1865 event_sched_in(struct perf_event *event,
1866 struct perf_cpu_context *cpuctx,
1867 struct perf_event_context *ctx)
1869 u64 tstamp = perf_event_time(event);
1872 lockdep_assert_held(&ctx->lock);
1874 if (event->state <= PERF_EVENT_STATE_OFF)
1877 event->state = PERF_EVENT_STATE_ACTIVE;
1878 event->oncpu = smp_processor_id();
1881 * Unthrottle events, since we scheduled we might have missed several
1882 * ticks already, also for a heavily scheduling task there is little
1883 * guarantee it'll get a tick in a timely manner.
1885 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1886 perf_log_throttle(event, 1);
1887 event->hw.interrupts = 0;
1891 * The new state must be visible before we turn it on in the hardware:
1895 perf_pmu_disable(event->pmu);
1897 perf_set_shadow_time(event, ctx, tstamp);
1899 perf_log_itrace_start(event);
1901 if (event->pmu->add(event, PERF_EF_START)) {
1902 event->state = PERF_EVENT_STATE_INACTIVE;
1908 event->tstamp_running += tstamp - event->tstamp_stopped;
1910 if (!is_software_event(event))
1911 cpuctx->active_oncpu++;
1912 if (!ctx->nr_active++)
1913 perf_event_ctx_activate(ctx);
1914 if (event->attr.freq && event->attr.sample_freq)
1917 if (event->attr.exclusive)
1918 cpuctx->exclusive = 1;
1920 if (is_orphaned_child(event))
1921 schedule_orphans_remove(ctx);
1924 perf_pmu_enable(event->pmu);
1930 group_sched_in(struct perf_event *group_event,
1931 struct perf_cpu_context *cpuctx,
1932 struct perf_event_context *ctx)
1934 struct perf_event *event, *partial_group = NULL;
1935 struct pmu *pmu = ctx->pmu;
1936 u64 now = ctx->time;
1937 bool simulate = false;
1939 if (group_event->state == PERF_EVENT_STATE_OFF)
1942 pmu->start_txn(pmu);
1944 if (event_sched_in(group_event, cpuctx, ctx)) {
1945 pmu->cancel_txn(pmu);
1946 perf_mux_hrtimer_restart(cpuctx);
1951 * Schedule in siblings as one group (if any):
1953 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1954 if (event_sched_in(event, cpuctx, ctx)) {
1955 partial_group = event;
1960 if (!pmu->commit_txn(pmu))
1965 * Groups can be scheduled in as one unit only, so undo any
1966 * partial group before returning:
1967 * The events up to the failed event are scheduled out normally,
1968 * tstamp_stopped will be updated.
1970 * The failed events and the remaining siblings need to have
1971 * their timings updated as if they had gone thru event_sched_in()
1972 * and event_sched_out(). This is required to get consistent timings
1973 * across the group. This also takes care of the case where the group
1974 * could never be scheduled by ensuring tstamp_stopped is set to mark
1975 * the time the event was actually stopped, such that time delta
1976 * calculation in update_event_times() is correct.
1978 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1979 if (event == partial_group)
1983 event->tstamp_running += now - event->tstamp_stopped;
1984 event->tstamp_stopped = now;
1986 event_sched_out(event, cpuctx, ctx);
1989 event_sched_out(group_event, cpuctx, ctx);
1991 pmu->cancel_txn(pmu);
1993 perf_mux_hrtimer_restart(cpuctx);
1999 * Work out whether we can put this event group on the CPU now.
2001 static int group_can_go_on(struct perf_event *event,
2002 struct perf_cpu_context *cpuctx,
2006 * Groups consisting entirely of software events can always go on.
2008 if (event->group_flags & PERF_GROUP_SOFTWARE)
2011 * If an exclusive group is already on, no other hardware
2014 if (cpuctx->exclusive)
2017 * If this group is exclusive and there are already
2018 * events on the CPU, it can't go on.
2020 if (event->attr.exclusive && cpuctx->active_oncpu)
2023 * Otherwise, try to add it if all previous groups were able
2029 static void add_event_to_ctx(struct perf_event *event,
2030 struct perf_event_context *ctx)
2032 u64 tstamp = perf_event_time(event);
2034 list_add_event(event, ctx);
2035 perf_group_attach(event);
2036 event->tstamp_enabled = tstamp;
2037 event->tstamp_running = tstamp;
2038 event->tstamp_stopped = tstamp;
2041 static void task_ctx_sched_out(struct perf_event_context *ctx);
2043 ctx_sched_in(struct perf_event_context *ctx,
2044 struct perf_cpu_context *cpuctx,
2045 enum event_type_t event_type,
2046 struct task_struct *task);
2048 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2049 struct perf_event_context *ctx,
2050 struct task_struct *task)
2052 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2054 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2055 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2057 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2061 * Cross CPU call to install and enable a performance event
2063 * Must be called with ctx->mutex held
2065 static int __perf_install_in_context(void *info)
2067 struct perf_event *event = info;
2068 struct perf_event_context *ctx = event->ctx;
2069 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2070 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2071 struct task_struct *task = current;
2073 perf_ctx_lock(cpuctx, task_ctx);
2074 perf_pmu_disable(cpuctx->ctx.pmu);
2077 * If there was an active task_ctx schedule it out.
2080 task_ctx_sched_out(task_ctx);
2083 * If the context we're installing events in is not the
2084 * active task_ctx, flip them.
2086 if (ctx->task && task_ctx != ctx) {
2088 raw_spin_unlock(&task_ctx->lock);
2089 raw_spin_lock(&ctx->lock);
2094 cpuctx->task_ctx = task_ctx;
2095 task = task_ctx->task;
2098 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2100 update_context_time(ctx);
2102 * update cgrp time only if current cgrp
2103 * matches event->cgrp. Must be done before
2104 * calling add_event_to_ctx()
2106 update_cgrp_time_from_event(event);
2108 add_event_to_ctx(event, ctx);
2111 * Schedule everything back in
2113 perf_event_sched_in(cpuctx, task_ctx, task);
2115 perf_pmu_enable(cpuctx->ctx.pmu);
2116 perf_ctx_unlock(cpuctx, task_ctx);
2122 * Attach a performance event to a context
2124 * First we add the event to the list with the hardware enable bit
2125 * in event->hw_config cleared.
2127 * If the event is attached to a task which is on a CPU we use a smp
2128 * call to enable it in the task context. The task might have been
2129 * scheduled away, but we check this in the smp call again.
2132 perf_install_in_context(struct perf_event_context *ctx,
2133 struct perf_event *event,
2136 struct task_struct *task = ctx->task;
2138 lockdep_assert_held(&ctx->mutex);
2141 if (event->cpu != -1)
2146 * Per cpu events are installed via an smp call and
2147 * the install is always successful.
2149 cpu_function_call(cpu, __perf_install_in_context, event);
2154 if (!task_function_call(task, __perf_install_in_context, event))
2157 raw_spin_lock_irq(&ctx->lock);
2159 * If we failed to find a running task, but find the context active now
2160 * that we've acquired the ctx->lock, retry.
2162 if (ctx->is_active) {
2163 raw_spin_unlock_irq(&ctx->lock);
2165 * Reload the task pointer, it might have been changed by
2166 * a concurrent perf_event_context_sched_out().
2173 * Since the task isn't running, its safe to add the event, us holding
2174 * the ctx->lock ensures the task won't get scheduled in.
2176 add_event_to_ctx(event, ctx);
2177 raw_spin_unlock_irq(&ctx->lock);
2181 * Put a event into inactive state and update time fields.
2182 * Enabling the leader of a group effectively enables all
2183 * the group members that aren't explicitly disabled, so we
2184 * have to update their ->tstamp_enabled also.
2185 * Note: this works for group members as well as group leaders
2186 * since the non-leader members' sibling_lists will be empty.
2188 static void __perf_event_mark_enabled(struct perf_event *event)
2190 struct perf_event *sub;
2191 u64 tstamp = perf_event_time(event);
2193 event->state = PERF_EVENT_STATE_INACTIVE;
2194 event->tstamp_enabled = tstamp - event->total_time_enabled;
2195 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2196 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2197 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2202 * Cross CPU call to enable a performance event
2204 static int __perf_event_enable(void *info)
2206 struct perf_event *event = info;
2207 struct perf_event_context *ctx = event->ctx;
2208 struct perf_event *leader = event->group_leader;
2209 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2213 * There's a time window between 'ctx->is_active' check
2214 * in perf_event_enable function and this place having:
2216 * - ctx->lock unlocked
2218 * where the task could be killed and 'ctx' deactivated
2219 * by perf_event_exit_task.
2221 if (!ctx->is_active)
2224 raw_spin_lock(&ctx->lock);
2225 update_context_time(ctx);
2227 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2231 * set current task's cgroup time reference point
2233 perf_cgroup_set_timestamp(current, ctx);
2235 __perf_event_mark_enabled(event);
2237 if (!event_filter_match(event)) {
2238 if (is_cgroup_event(event))
2239 perf_cgroup_defer_enabled(event);
2244 * If the event is in a group and isn't the group leader,
2245 * then don't put it on unless the group is on.
2247 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2250 if (!group_can_go_on(event, cpuctx, 1)) {
2253 if (event == leader)
2254 err = group_sched_in(event, cpuctx, ctx);
2256 err = event_sched_in(event, cpuctx, ctx);
2261 * If this event can't go on and it's part of a
2262 * group, then the whole group has to come off.
2264 if (leader != event) {
2265 group_sched_out(leader, cpuctx, ctx);
2266 perf_mux_hrtimer_restart(cpuctx);
2268 if (leader->attr.pinned) {
2269 update_group_times(leader);
2270 leader->state = PERF_EVENT_STATE_ERROR;
2275 raw_spin_unlock(&ctx->lock);
2283 * If event->ctx is a cloned context, callers must make sure that
2284 * every task struct that event->ctx->task could possibly point to
2285 * remains valid. This condition is satisfied when called through
2286 * perf_event_for_each_child or perf_event_for_each as described
2287 * for perf_event_disable.
2289 static void _perf_event_enable(struct perf_event *event)
2291 struct perf_event_context *ctx = event->ctx;
2292 struct task_struct *task = ctx->task;
2296 * Enable the event on the cpu that it's on
2298 cpu_function_call(event->cpu, __perf_event_enable, event);
2302 raw_spin_lock_irq(&ctx->lock);
2303 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2307 * If the event is in error state, clear that first.
2308 * That way, if we see the event in error state below, we
2309 * know that it has gone back into error state, as distinct
2310 * from the task having been scheduled away before the
2311 * cross-call arrived.
2313 if (event->state == PERF_EVENT_STATE_ERROR)
2314 event->state = PERF_EVENT_STATE_OFF;
2317 if (!ctx->is_active) {
2318 __perf_event_mark_enabled(event);
2322 raw_spin_unlock_irq(&ctx->lock);
2324 if (!task_function_call(task, __perf_event_enable, event))
2327 raw_spin_lock_irq(&ctx->lock);
2330 * If the context is active and the event is still off,
2331 * we need to retry the cross-call.
2333 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2335 * task could have been flipped by a concurrent
2336 * perf_event_context_sched_out()
2343 raw_spin_unlock_irq(&ctx->lock);
2347 * See perf_event_disable();
2349 void perf_event_enable(struct perf_event *event)
2351 struct perf_event_context *ctx;
2353 ctx = perf_event_ctx_lock(event);
2354 _perf_event_enable(event);
2355 perf_event_ctx_unlock(event, ctx);
2357 EXPORT_SYMBOL_GPL(perf_event_enable);
2359 static int _perf_event_refresh(struct perf_event *event, int refresh)
2362 * not supported on inherited events
2364 if (event->attr.inherit || !is_sampling_event(event))
2367 atomic_add(refresh, &event->event_limit);
2368 _perf_event_enable(event);
2374 * See perf_event_disable()
2376 int perf_event_refresh(struct perf_event *event, int refresh)
2378 struct perf_event_context *ctx;
2381 ctx = perf_event_ctx_lock(event);
2382 ret = _perf_event_refresh(event, refresh);
2383 perf_event_ctx_unlock(event, ctx);
2387 EXPORT_SYMBOL_GPL(perf_event_refresh);
2389 static void ctx_sched_out(struct perf_event_context *ctx,
2390 struct perf_cpu_context *cpuctx,
2391 enum event_type_t event_type)
2393 struct perf_event *event;
2394 int is_active = ctx->is_active;
2396 ctx->is_active &= ~event_type;
2397 if (likely(!ctx->nr_events))
2400 update_context_time(ctx);
2401 update_cgrp_time_from_cpuctx(cpuctx);
2402 if (!ctx->nr_active)
2405 perf_pmu_disable(ctx->pmu);
2406 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2407 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2408 group_sched_out(event, cpuctx, ctx);
2411 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2412 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2413 group_sched_out(event, cpuctx, ctx);
2415 perf_pmu_enable(ctx->pmu);
2419 * Test whether two contexts are equivalent, i.e. whether they have both been
2420 * cloned from the same version of the same context.
2422 * Equivalence is measured using a generation number in the context that is
2423 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2424 * and list_del_event().
2426 static int context_equiv(struct perf_event_context *ctx1,
2427 struct perf_event_context *ctx2)
2429 lockdep_assert_held(&ctx1->lock);
2430 lockdep_assert_held(&ctx2->lock);
2432 /* Pinning disables the swap optimization */
2433 if (ctx1->pin_count || ctx2->pin_count)
2436 /* If ctx1 is the parent of ctx2 */
2437 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2440 /* If ctx2 is the parent of ctx1 */
2441 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2445 * If ctx1 and ctx2 have the same parent; we flatten the parent
2446 * hierarchy, see perf_event_init_context().
2448 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2449 ctx1->parent_gen == ctx2->parent_gen)
2456 static void __perf_event_sync_stat(struct perf_event *event,
2457 struct perf_event *next_event)
2461 if (!event->attr.inherit_stat)
2465 * Update the event value, we cannot use perf_event_read()
2466 * because we're in the middle of a context switch and have IRQs
2467 * disabled, which upsets smp_call_function_single(), however
2468 * we know the event must be on the current CPU, therefore we
2469 * don't need to use it.
2471 switch (event->state) {
2472 case PERF_EVENT_STATE_ACTIVE:
2473 event->pmu->read(event);
2476 case PERF_EVENT_STATE_INACTIVE:
2477 update_event_times(event);
2485 * In order to keep per-task stats reliable we need to flip the event
2486 * values when we flip the contexts.
2488 value = local64_read(&next_event->count);
2489 value = local64_xchg(&event->count, value);
2490 local64_set(&next_event->count, value);
2492 swap(event->total_time_enabled, next_event->total_time_enabled);
2493 swap(event->total_time_running, next_event->total_time_running);
2496 * Since we swizzled the values, update the user visible data too.
2498 perf_event_update_userpage(event);
2499 perf_event_update_userpage(next_event);
2502 static void perf_event_sync_stat(struct perf_event_context *ctx,
2503 struct perf_event_context *next_ctx)
2505 struct perf_event *event, *next_event;
2510 update_context_time(ctx);
2512 event = list_first_entry(&ctx->event_list,
2513 struct perf_event, event_entry);
2515 next_event = list_first_entry(&next_ctx->event_list,
2516 struct perf_event, event_entry);
2518 while (&event->event_entry != &ctx->event_list &&
2519 &next_event->event_entry != &next_ctx->event_list) {
2521 __perf_event_sync_stat(event, next_event);
2523 event = list_next_entry(event, event_entry);
2524 next_event = list_next_entry(next_event, event_entry);
2528 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2529 struct task_struct *next)
2531 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2532 struct perf_event_context *next_ctx;
2533 struct perf_event_context *parent, *next_parent;
2534 struct perf_cpu_context *cpuctx;
2540 cpuctx = __get_cpu_context(ctx);
2541 if (!cpuctx->task_ctx)
2545 next_ctx = next->perf_event_ctxp[ctxn];
2549 parent = rcu_dereference(ctx->parent_ctx);
2550 next_parent = rcu_dereference(next_ctx->parent_ctx);
2552 /* If neither context have a parent context; they cannot be clones. */
2553 if (!parent && !next_parent)
2556 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2558 * Looks like the two contexts are clones, so we might be
2559 * able to optimize the context switch. We lock both
2560 * contexts and check that they are clones under the
2561 * lock (including re-checking that neither has been
2562 * uncloned in the meantime). It doesn't matter which
2563 * order we take the locks because no other cpu could
2564 * be trying to lock both of these tasks.
2566 raw_spin_lock(&ctx->lock);
2567 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2568 if (context_equiv(ctx, next_ctx)) {
2570 * XXX do we need a memory barrier of sorts
2571 * wrt to rcu_dereference() of perf_event_ctxp
2573 task->perf_event_ctxp[ctxn] = next_ctx;
2574 next->perf_event_ctxp[ctxn] = ctx;
2576 next_ctx->task = task;
2578 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2582 perf_event_sync_stat(ctx, next_ctx);
2584 raw_spin_unlock(&next_ctx->lock);
2585 raw_spin_unlock(&ctx->lock);
2591 raw_spin_lock(&ctx->lock);
2592 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2593 cpuctx->task_ctx = NULL;
2594 raw_spin_unlock(&ctx->lock);
2598 void perf_sched_cb_dec(struct pmu *pmu)
2600 this_cpu_dec(perf_sched_cb_usages);
2603 void perf_sched_cb_inc(struct pmu *pmu)
2605 this_cpu_inc(perf_sched_cb_usages);
2609 * This function provides the context switch callback to the lower code
2610 * layer. It is invoked ONLY when the context switch callback is enabled.
2612 static void perf_pmu_sched_task(struct task_struct *prev,
2613 struct task_struct *next,
2616 struct perf_cpu_context *cpuctx;
2618 unsigned long flags;
2623 local_irq_save(flags);
2627 list_for_each_entry_rcu(pmu, &pmus, entry) {
2628 if (pmu->sched_task) {
2629 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2631 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2633 perf_pmu_disable(pmu);
2635 pmu->sched_task(cpuctx->task_ctx, sched_in);
2637 perf_pmu_enable(pmu);
2639 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2645 local_irq_restore(flags);
2648 static void perf_event_switch(struct task_struct *task,
2649 struct task_struct *next_prev, bool sched_in);
2651 #define for_each_task_context_nr(ctxn) \
2652 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2655 * Called from scheduler to remove the events of the current task,
2656 * with interrupts disabled.
2658 * We stop each event and update the event value in event->count.
2660 * This does not protect us against NMI, but disable()
2661 * sets the disabled bit in the control field of event _before_
2662 * accessing the event control register. If a NMI hits, then it will
2663 * not restart the event.
2665 void __perf_event_task_sched_out(struct task_struct *task,
2666 struct task_struct *next)
2670 if (__this_cpu_read(perf_sched_cb_usages))
2671 perf_pmu_sched_task(task, next, false);
2673 if (atomic_read(&nr_switch_events))
2674 perf_event_switch(task, next, false);
2676 for_each_task_context_nr(ctxn)
2677 perf_event_context_sched_out(task, ctxn, next);
2680 * if cgroup events exist on this CPU, then we need
2681 * to check if we have to switch out PMU state.
2682 * cgroup event are system-wide mode only
2684 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2685 perf_cgroup_sched_out(task, next);
2688 static void task_ctx_sched_out(struct perf_event_context *ctx)
2690 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2692 if (!cpuctx->task_ctx)
2695 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2698 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2699 cpuctx->task_ctx = NULL;
2703 * Called with IRQs disabled
2705 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2706 enum event_type_t event_type)
2708 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2712 ctx_pinned_sched_in(struct perf_event_context *ctx,
2713 struct perf_cpu_context *cpuctx)
2715 struct perf_event *event;
2717 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2718 if (event->state <= PERF_EVENT_STATE_OFF)
2720 if (!event_filter_match(event))
2723 /* may need to reset tstamp_enabled */
2724 if (is_cgroup_event(event))
2725 perf_cgroup_mark_enabled(event, ctx);
2727 if (group_can_go_on(event, cpuctx, 1))
2728 group_sched_in(event, cpuctx, ctx);
2731 * If this pinned group hasn't been scheduled,
2732 * put it in error state.
2734 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2735 update_group_times(event);
2736 event->state = PERF_EVENT_STATE_ERROR;
2742 ctx_flexible_sched_in(struct perf_event_context *ctx,
2743 struct perf_cpu_context *cpuctx)
2745 struct perf_event *event;
2748 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2749 /* Ignore events in OFF or ERROR state */
2750 if (event->state <= PERF_EVENT_STATE_OFF)
2753 * Listen to the 'cpu' scheduling filter constraint
2756 if (!event_filter_match(event))
2759 /* may need to reset tstamp_enabled */
2760 if (is_cgroup_event(event))
2761 perf_cgroup_mark_enabled(event, ctx);
2763 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2764 if (group_sched_in(event, cpuctx, ctx))
2771 ctx_sched_in(struct perf_event_context *ctx,
2772 struct perf_cpu_context *cpuctx,
2773 enum event_type_t event_type,
2774 struct task_struct *task)
2777 int is_active = ctx->is_active;
2779 ctx->is_active |= event_type;
2780 if (likely(!ctx->nr_events))
2784 ctx->timestamp = now;
2785 perf_cgroup_set_timestamp(task, ctx);
2787 * First go through the list and put on any pinned groups
2788 * in order to give them the best chance of going on.
2790 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2791 ctx_pinned_sched_in(ctx, cpuctx);
2793 /* Then walk through the lower prio flexible groups */
2794 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2795 ctx_flexible_sched_in(ctx, cpuctx);
2798 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2799 enum event_type_t event_type,
2800 struct task_struct *task)
2802 struct perf_event_context *ctx = &cpuctx->ctx;
2804 ctx_sched_in(ctx, cpuctx, event_type, task);
2807 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2808 struct task_struct *task)
2810 struct perf_cpu_context *cpuctx;
2812 cpuctx = __get_cpu_context(ctx);
2813 if (cpuctx->task_ctx == ctx)
2816 perf_ctx_lock(cpuctx, ctx);
2817 perf_pmu_disable(ctx->pmu);
2819 * We want to keep the following priority order:
2820 * cpu pinned (that don't need to move), task pinned,
2821 * cpu flexible, task flexible.
2823 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2826 cpuctx->task_ctx = ctx;
2828 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2830 perf_pmu_enable(ctx->pmu);
2831 perf_ctx_unlock(cpuctx, ctx);
2835 * Called from scheduler to add the events of the current task
2836 * with interrupts disabled.
2838 * We restore the event value and then enable it.
2840 * This does not protect us against NMI, but enable()
2841 * sets the enabled bit in the control field of event _before_
2842 * accessing the event control register. If a NMI hits, then it will
2843 * keep the event running.
2845 void __perf_event_task_sched_in(struct task_struct *prev,
2846 struct task_struct *task)
2848 struct perf_event_context *ctx;
2851 for_each_task_context_nr(ctxn) {
2852 ctx = task->perf_event_ctxp[ctxn];
2856 perf_event_context_sched_in(ctx, task);
2859 * if cgroup events exist on this CPU, then we need
2860 * to check if we have to switch in PMU state.
2861 * cgroup event are system-wide mode only
2863 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2864 perf_cgroup_sched_in(prev, task);
2866 if (atomic_read(&nr_switch_events))
2867 perf_event_switch(task, prev, true);
2869 if (__this_cpu_read(perf_sched_cb_usages))
2870 perf_pmu_sched_task(prev, task, true);
2873 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2875 u64 frequency = event->attr.sample_freq;
2876 u64 sec = NSEC_PER_SEC;
2877 u64 divisor, dividend;
2879 int count_fls, nsec_fls, frequency_fls, sec_fls;
2881 count_fls = fls64(count);
2882 nsec_fls = fls64(nsec);
2883 frequency_fls = fls64(frequency);
2887 * We got @count in @nsec, with a target of sample_freq HZ
2888 * the target period becomes:
2891 * period = -------------------
2892 * @nsec * sample_freq
2897 * Reduce accuracy by one bit such that @a and @b converge
2898 * to a similar magnitude.
2900 #define REDUCE_FLS(a, b) \
2902 if (a##_fls > b##_fls) { \
2912 * Reduce accuracy until either term fits in a u64, then proceed with
2913 * the other, so that finally we can do a u64/u64 division.
2915 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2916 REDUCE_FLS(nsec, frequency);
2917 REDUCE_FLS(sec, count);
2920 if (count_fls + sec_fls > 64) {
2921 divisor = nsec * frequency;
2923 while (count_fls + sec_fls > 64) {
2924 REDUCE_FLS(count, sec);
2928 dividend = count * sec;
2930 dividend = count * sec;
2932 while (nsec_fls + frequency_fls > 64) {
2933 REDUCE_FLS(nsec, frequency);
2937 divisor = nsec * frequency;
2943 return div64_u64(dividend, divisor);
2946 static DEFINE_PER_CPU(int, perf_throttled_count);
2947 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2949 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2951 struct hw_perf_event *hwc = &event->hw;
2952 s64 period, sample_period;
2955 period = perf_calculate_period(event, nsec, count);
2957 delta = (s64)(period - hwc->sample_period);
2958 delta = (delta + 7) / 8; /* low pass filter */
2960 sample_period = hwc->sample_period + delta;
2965 hwc->sample_period = sample_period;
2967 if (local64_read(&hwc->period_left) > 8*sample_period) {
2969 event->pmu->stop(event, PERF_EF_UPDATE);
2971 local64_set(&hwc->period_left, 0);
2974 event->pmu->start(event, PERF_EF_RELOAD);
2979 * combine freq adjustment with unthrottling to avoid two passes over the
2980 * events. At the same time, make sure, having freq events does not change
2981 * the rate of unthrottling as that would introduce bias.
2983 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2986 struct perf_event *event;
2987 struct hw_perf_event *hwc;
2988 u64 now, period = TICK_NSEC;
2992 * only need to iterate over all events iff:
2993 * - context have events in frequency mode (needs freq adjust)
2994 * - there are events to unthrottle on this cpu
2996 if (!(ctx->nr_freq || needs_unthr))
2999 raw_spin_lock(&ctx->lock);
3000 perf_pmu_disable(ctx->pmu);
3002 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3003 if (event->state != PERF_EVENT_STATE_ACTIVE)
3006 if (!event_filter_match(event))
3009 perf_pmu_disable(event->pmu);
3013 if (hwc->interrupts == MAX_INTERRUPTS) {
3014 hwc->interrupts = 0;
3015 perf_log_throttle(event, 1);
3016 event->pmu->start(event, 0);
3019 if (!event->attr.freq || !event->attr.sample_freq)
3023 * stop the event and update event->count
3025 event->pmu->stop(event, PERF_EF_UPDATE);
3027 now = local64_read(&event->count);
3028 delta = now - hwc->freq_count_stamp;
3029 hwc->freq_count_stamp = now;
3033 * reload only if value has changed
3034 * we have stopped the event so tell that
3035 * to perf_adjust_period() to avoid stopping it
3039 perf_adjust_period(event, period, delta, false);
3041 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3043 perf_pmu_enable(event->pmu);
3046 perf_pmu_enable(ctx->pmu);
3047 raw_spin_unlock(&ctx->lock);
3051 * Round-robin a context's events:
3053 static void rotate_ctx(struct perf_event_context *ctx)
3056 * Rotate the first entry last of non-pinned groups. Rotation might be
3057 * disabled by the inheritance code.
3059 if (!ctx->rotate_disable)
3060 list_rotate_left(&ctx->flexible_groups);
3063 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3065 struct perf_event_context *ctx = NULL;
3068 if (cpuctx->ctx.nr_events) {
3069 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3073 ctx = cpuctx->task_ctx;
3074 if (ctx && ctx->nr_events) {
3075 if (ctx->nr_events != ctx->nr_active)
3082 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3083 perf_pmu_disable(cpuctx->ctx.pmu);
3085 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3087 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3089 rotate_ctx(&cpuctx->ctx);
3093 perf_event_sched_in(cpuctx, ctx, current);
3095 perf_pmu_enable(cpuctx->ctx.pmu);
3096 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3102 #ifdef CONFIG_NO_HZ_FULL
3103 bool perf_event_can_stop_tick(void)
3105 if (atomic_read(&nr_freq_events) ||
3106 __this_cpu_read(perf_throttled_count))
3113 void perf_event_task_tick(void)
3115 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3116 struct perf_event_context *ctx, *tmp;
3119 WARN_ON(!irqs_disabled());
3121 __this_cpu_inc(perf_throttled_seq);
3122 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3124 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3125 perf_adjust_freq_unthr_context(ctx, throttled);
3128 static int event_enable_on_exec(struct perf_event *event,
3129 struct perf_event_context *ctx)
3131 if (!event->attr.enable_on_exec)
3134 event->attr.enable_on_exec = 0;
3135 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3138 __perf_event_mark_enabled(event);
3144 * Enable all of a task's events that have been marked enable-on-exec.
3145 * This expects task == current.
3147 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
3149 struct perf_event_context *clone_ctx = NULL;
3150 struct perf_event *event;
3151 unsigned long flags;
3155 local_irq_save(flags);
3156 if (!ctx || !ctx->nr_events)
3160 * We must ctxsw out cgroup events to avoid conflict
3161 * when invoking perf_task_event_sched_in() later on
3162 * in this function. Otherwise we end up trying to
3163 * ctxswin cgroup events which are already scheduled
3166 perf_cgroup_sched_out(current, NULL);
3168 raw_spin_lock(&ctx->lock);
3169 task_ctx_sched_out(ctx);
3171 list_for_each_entry(event, &ctx->event_list, event_entry) {
3172 ret = event_enable_on_exec(event, ctx);
3178 * Unclone this context if we enabled any event.
3181 clone_ctx = unclone_ctx(ctx);
3183 raw_spin_unlock(&ctx->lock);
3186 * Also calls ctxswin for cgroup events, if any:
3188 perf_event_context_sched_in(ctx, ctx->task);
3190 local_irq_restore(flags);
3196 void perf_event_exec(void)
3198 struct perf_event_context *ctx;
3202 for_each_task_context_nr(ctxn) {
3203 ctx = current->perf_event_ctxp[ctxn];
3207 perf_event_enable_on_exec(ctx);
3213 * Cross CPU call to read the hardware event
3215 static void __perf_event_read(void *info)
3217 struct perf_event *event = info;
3218 struct perf_event_context *ctx = event->ctx;
3219 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3222 * If this is a task context, we need to check whether it is
3223 * the current task context of this cpu. If not it has been
3224 * scheduled out before the smp call arrived. In that case
3225 * event->count would have been updated to a recent sample
3226 * when the event was scheduled out.
3228 if (ctx->task && cpuctx->task_ctx != ctx)
3231 raw_spin_lock(&ctx->lock);
3232 if (ctx->is_active) {
3233 update_context_time(ctx);
3234 update_cgrp_time_from_event(event);
3236 update_event_times(event);
3237 if (event->state == PERF_EVENT_STATE_ACTIVE)
3238 event->pmu->read(event);
3239 raw_spin_unlock(&ctx->lock);
3242 static inline u64 perf_event_count(struct perf_event *event)
3244 if (event->pmu->count)
3245 return event->pmu->count(event);
3247 return __perf_event_count(event);
3251 * NMI-safe method to read a local event, that is an event that
3253 * - either for the current task, or for this CPU
3254 * - does not have inherit set, for inherited task events
3255 * will not be local and we cannot read them atomically
3256 * - must not have a pmu::count method
3258 u64 perf_event_read_local(struct perf_event *event)
3260 unsigned long flags;
3264 * Disabling interrupts avoids all counter scheduling (context
3265 * switches, timer based rotation and IPIs).
3267 local_irq_save(flags);
3269 /* If this is a per-task event, it must be for current */
3270 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3271 event->hw.target != current);
3273 /* If this is a per-CPU event, it must be for this CPU */
3274 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3275 event->cpu != smp_processor_id());
3278 * It must not be an event with inherit set, we cannot read
3279 * all child counters from atomic context.
3281 WARN_ON_ONCE(event->attr.inherit);
3284 * It must not have a pmu::count method, those are not
3287 WARN_ON_ONCE(event->pmu->count);
3290 * If the event is currently on this CPU, its either a per-task event,
3291 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3294 if (event->oncpu == smp_processor_id())
3295 event->pmu->read(event);
3297 val = local64_read(&event->count);
3298 local_irq_restore(flags);
3303 static u64 perf_event_read(struct perf_event *event)
3306 * If event is enabled and currently active on a CPU, update the
3307 * value in the event structure:
3309 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3310 smp_call_function_single(event->oncpu,
3311 __perf_event_read, event, 1);
3312 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3313 struct perf_event_context *ctx = event->ctx;
3314 unsigned long flags;
3316 raw_spin_lock_irqsave(&ctx->lock, flags);
3318 * may read while context is not active
3319 * (e.g., thread is blocked), in that case
3320 * we cannot update context time
3322 if (ctx->is_active) {
3323 update_context_time(ctx);
3324 update_cgrp_time_from_event(event);
3326 update_event_times(event);
3327 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3330 return perf_event_count(event);
3334 * Initialize the perf_event context in a task_struct:
3336 static void __perf_event_init_context(struct perf_event_context *ctx)
3338 raw_spin_lock_init(&ctx->lock);
3339 mutex_init(&ctx->mutex);
3340 INIT_LIST_HEAD(&ctx->active_ctx_list);
3341 INIT_LIST_HEAD(&ctx->pinned_groups);
3342 INIT_LIST_HEAD(&ctx->flexible_groups);
3343 INIT_LIST_HEAD(&ctx->event_list);
3344 atomic_set(&ctx->refcount, 1);
3345 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3348 static struct perf_event_context *
3349 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3351 struct perf_event_context *ctx;
3353 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3357 __perf_event_init_context(ctx);
3360 get_task_struct(task);
3367 static struct task_struct *
3368 find_lively_task_by_vpid(pid_t vpid)
3370 struct task_struct *task;
3377 task = find_task_by_vpid(vpid);
3379 get_task_struct(task);
3383 return ERR_PTR(-ESRCH);
3385 /* Reuse ptrace permission checks for now. */
3387 if (!ptrace_may_access(task, PTRACE_MODE_READ))
3392 put_task_struct(task);
3393 return ERR_PTR(err);
3398 * Returns a matching context with refcount and pincount.
3400 static struct perf_event_context *
3401 find_get_context(struct pmu *pmu, struct task_struct *task,
3402 struct perf_event *event)
3404 struct perf_event_context *ctx, *clone_ctx = NULL;
3405 struct perf_cpu_context *cpuctx;
3406 void *task_ctx_data = NULL;
3407 unsigned long flags;
3409 int cpu = event->cpu;
3412 /* Must be root to operate on a CPU event: */
3413 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3414 return ERR_PTR(-EACCES);
3417 * We could be clever and allow to attach a event to an
3418 * offline CPU and activate it when the CPU comes up, but
3421 if (!cpu_online(cpu))
3422 return ERR_PTR(-ENODEV);
3424 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3433 ctxn = pmu->task_ctx_nr;
3437 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3438 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3439 if (!task_ctx_data) {
3446 ctx = perf_lock_task_context(task, ctxn, &flags);
3448 clone_ctx = unclone_ctx(ctx);
3451 if (task_ctx_data && !ctx->task_ctx_data) {
3452 ctx->task_ctx_data = task_ctx_data;
3453 task_ctx_data = NULL;
3455 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3460 ctx = alloc_perf_context(pmu, task);
3465 if (task_ctx_data) {
3466 ctx->task_ctx_data = task_ctx_data;
3467 task_ctx_data = NULL;
3471 mutex_lock(&task->perf_event_mutex);
3473 * If it has already passed perf_event_exit_task().
3474 * we must see PF_EXITING, it takes this mutex too.
3476 if (task->flags & PF_EXITING)
3478 else if (task->perf_event_ctxp[ctxn])
3483 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3485 mutex_unlock(&task->perf_event_mutex);
3487 if (unlikely(err)) {
3496 kfree(task_ctx_data);
3500 kfree(task_ctx_data);
3501 return ERR_PTR(err);
3504 static void perf_event_free_filter(struct perf_event *event);
3505 static void perf_event_free_bpf_prog(struct perf_event *event);
3507 static void free_event_rcu(struct rcu_head *head)
3509 struct perf_event *event;
3511 event = container_of(head, struct perf_event, rcu_head);
3513 put_pid_ns(event->ns);
3514 perf_event_free_filter(event);
3518 static void ring_buffer_attach(struct perf_event *event,
3519 struct ring_buffer *rb);
3521 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3526 if (is_cgroup_event(event))
3527 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3530 static void unaccount_event(struct perf_event *event)
3535 if (event->attach_state & PERF_ATTACH_TASK)
3536 static_key_slow_dec_deferred(&perf_sched_events);
3537 if (event->attr.mmap || event->attr.mmap_data)
3538 atomic_dec(&nr_mmap_events);
3539 if (event->attr.comm)
3540 atomic_dec(&nr_comm_events);
3541 if (event->attr.task)
3542 atomic_dec(&nr_task_events);
3543 if (event->attr.freq)
3544 atomic_dec(&nr_freq_events);
3545 if (event->attr.context_switch) {
3546 static_key_slow_dec_deferred(&perf_sched_events);
3547 atomic_dec(&nr_switch_events);
3549 if (is_cgroup_event(event))
3550 static_key_slow_dec_deferred(&perf_sched_events);
3551 if (has_branch_stack(event))
3552 static_key_slow_dec_deferred(&perf_sched_events);
3554 unaccount_event_cpu(event, event->cpu);
3558 * The following implement mutual exclusion of events on "exclusive" pmus
3559 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3560 * at a time, so we disallow creating events that might conflict, namely:
3562 * 1) cpu-wide events in the presence of per-task events,
3563 * 2) per-task events in the presence of cpu-wide events,
3564 * 3) two matching events on the same context.
3566 * The former two cases are handled in the allocation path (perf_event_alloc(),
3567 * __free_event()), the latter -- before the first perf_install_in_context().
3569 static int exclusive_event_init(struct perf_event *event)
3571 struct pmu *pmu = event->pmu;
3573 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3577 * Prevent co-existence of per-task and cpu-wide events on the
3578 * same exclusive pmu.
3580 * Negative pmu::exclusive_cnt means there are cpu-wide
3581 * events on this "exclusive" pmu, positive means there are
3584 * Since this is called in perf_event_alloc() path, event::ctx
3585 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3586 * to mean "per-task event", because unlike other attach states it
3587 * never gets cleared.
3589 if (event->attach_state & PERF_ATTACH_TASK) {
3590 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3593 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3600 static void exclusive_event_destroy(struct perf_event *event)
3602 struct pmu *pmu = event->pmu;
3604 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3607 /* see comment in exclusive_event_init() */
3608 if (event->attach_state & PERF_ATTACH_TASK)
3609 atomic_dec(&pmu->exclusive_cnt);
3611 atomic_inc(&pmu->exclusive_cnt);
3614 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3616 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3617 (e1->cpu == e2->cpu ||
3624 /* Called under the same ctx::mutex as perf_install_in_context() */
3625 static bool exclusive_event_installable(struct perf_event *event,
3626 struct perf_event_context *ctx)
3628 struct perf_event *iter_event;
3629 struct pmu *pmu = event->pmu;
3631 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3634 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3635 if (exclusive_event_match(iter_event, event))
3642 static void __free_event(struct perf_event *event)
3644 if (!event->parent) {
3645 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3646 put_callchain_buffers();
3649 perf_event_free_bpf_prog(event);
3652 event->destroy(event);
3655 put_ctx(event->ctx);
3658 exclusive_event_destroy(event);
3659 module_put(event->pmu->module);
3662 call_rcu(&event->rcu_head, free_event_rcu);
3665 static void _free_event(struct perf_event *event)
3667 irq_work_sync(&event->pending);
3669 unaccount_event(event);
3673 * Can happen when we close an event with re-directed output.
3675 * Since we have a 0 refcount, perf_mmap_close() will skip
3676 * over us; possibly making our ring_buffer_put() the last.
3678 mutex_lock(&event->mmap_mutex);
3679 ring_buffer_attach(event, NULL);
3680 mutex_unlock(&event->mmap_mutex);
3683 if (is_cgroup_event(event))
3684 perf_detach_cgroup(event);
3686 __free_event(event);
3690 * Used to free events which have a known refcount of 1, such as in error paths
3691 * where the event isn't exposed yet and inherited events.
3693 static void free_event(struct perf_event *event)
3695 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3696 "unexpected event refcount: %ld; ptr=%p\n",
3697 atomic_long_read(&event->refcount), event)) {
3698 /* leak to avoid use-after-free */
3706 * Remove user event from the owner task.
3708 static void perf_remove_from_owner(struct perf_event *event)
3710 struct task_struct *owner;
3713 owner = ACCESS_ONCE(event->owner);
3715 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3716 * !owner it means the list deletion is complete and we can indeed
3717 * free this event, otherwise we need to serialize on
3718 * owner->perf_event_mutex.
3720 smp_read_barrier_depends();
3723 * Since delayed_put_task_struct() also drops the last
3724 * task reference we can safely take a new reference
3725 * while holding the rcu_read_lock().
3727 get_task_struct(owner);
3733 * If we're here through perf_event_exit_task() we're already
3734 * holding ctx->mutex which would be an inversion wrt. the
3735 * normal lock order.
3737 * However we can safely take this lock because its the child
3740 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3743 * We have to re-check the event->owner field, if it is cleared
3744 * we raced with perf_event_exit_task(), acquiring the mutex
3745 * ensured they're done, and we can proceed with freeing the
3749 list_del_init(&event->owner_entry);
3750 mutex_unlock(&owner->perf_event_mutex);
3751 put_task_struct(owner);
3755 static void put_event(struct perf_event *event)
3757 struct perf_event_context *ctx;
3759 if (!atomic_long_dec_and_test(&event->refcount))
3762 if (!is_kernel_event(event))
3763 perf_remove_from_owner(event);
3766 * There are two ways this annotation is useful:
3768 * 1) there is a lock recursion from perf_event_exit_task
3769 * see the comment there.
3771 * 2) there is a lock-inversion with mmap_sem through
3772 * perf_event_read_group(), which takes faults while
3773 * holding ctx->mutex, however this is called after
3774 * the last filedesc died, so there is no possibility
3775 * to trigger the AB-BA case.
3777 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3778 WARN_ON_ONCE(ctx->parent_ctx);
3779 perf_remove_from_context(event, true);
3780 perf_event_ctx_unlock(event, ctx);
3785 int perf_event_release_kernel(struct perf_event *event)
3790 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3793 * Called when the last reference to the file is gone.
3795 static int perf_release(struct inode *inode, struct file *file)
3797 put_event(file->private_data);
3802 * Remove all orphanes events from the context.
3804 static void orphans_remove_work(struct work_struct *work)
3806 struct perf_event_context *ctx;
3807 struct perf_event *event, *tmp;
3809 ctx = container_of(work, struct perf_event_context,
3810 orphans_remove.work);
3812 mutex_lock(&ctx->mutex);
3813 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3814 struct perf_event *parent_event = event->parent;
3816 if (!is_orphaned_child(event))
3819 perf_remove_from_context(event, true);
3821 mutex_lock(&parent_event->child_mutex);
3822 list_del_init(&event->child_list);
3823 mutex_unlock(&parent_event->child_mutex);
3826 put_event(parent_event);
3829 raw_spin_lock_irq(&ctx->lock);
3830 ctx->orphans_remove_sched = false;
3831 raw_spin_unlock_irq(&ctx->lock);
3832 mutex_unlock(&ctx->mutex);
3837 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3839 struct perf_event *child;
3845 mutex_lock(&event->child_mutex);
3846 total += perf_event_read(event);
3847 *enabled += event->total_time_enabled +
3848 atomic64_read(&event->child_total_time_enabled);
3849 *running += event->total_time_running +
3850 atomic64_read(&event->child_total_time_running);
3852 list_for_each_entry(child, &event->child_list, child_list) {
3853 total += perf_event_read(child);
3854 *enabled += child->total_time_enabled;
3855 *running += child->total_time_running;
3857 mutex_unlock(&event->child_mutex);
3861 EXPORT_SYMBOL_GPL(perf_event_read_value);
3863 static int perf_event_read_group(struct perf_event *event,
3864 u64 read_format, char __user *buf)
3866 struct perf_event *leader = event->group_leader, *sub;
3867 struct perf_event_context *ctx = leader->ctx;
3868 int n = 0, size = 0, ret;
3869 u64 count, enabled, running;
3872 lockdep_assert_held(&ctx->mutex);
3874 count = perf_event_read_value(leader, &enabled, &running);
3876 values[n++] = 1 + leader->nr_siblings;
3877 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3878 values[n++] = enabled;
3879 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3880 values[n++] = running;
3881 values[n++] = count;
3882 if (read_format & PERF_FORMAT_ID)
3883 values[n++] = primary_event_id(leader);
3885 size = n * sizeof(u64);
3887 if (copy_to_user(buf, values, size))
3892 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3895 values[n++] = perf_event_read_value(sub, &enabled, &running);
3896 if (read_format & PERF_FORMAT_ID)
3897 values[n++] = primary_event_id(sub);
3899 size = n * sizeof(u64);
3901 if (copy_to_user(buf + ret, values, size)) {
3911 static int perf_event_read_one(struct perf_event *event,
3912 u64 read_format, char __user *buf)
3914 u64 enabled, running;
3918 values[n++] = perf_event_read_value(event, &enabled, &running);
3919 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3920 values[n++] = enabled;
3921 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3922 values[n++] = running;
3923 if (read_format & PERF_FORMAT_ID)
3924 values[n++] = primary_event_id(event);
3926 if (copy_to_user(buf, values, n * sizeof(u64)))
3929 return n * sizeof(u64);
3932 static bool is_event_hup(struct perf_event *event)
3936 if (event->state != PERF_EVENT_STATE_EXIT)
3939 mutex_lock(&event->child_mutex);
3940 no_children = list_empty(&event->child_list);
3941 mutex_unlock(&event->child_mutex);
3946 * Read the performance event - simple non blocking version for now
3949 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3951 u64 read_format = event->attr.read_format;
3955 * Return end-of-file for a read on a event that is in
3956 * error state (i.e. because it was pinned but it couldn't be
3957 * scheduled on to the CPU at some point).
3959 if (event->state == PERF_EVENT_STATE_ERROR)
3962 if (count < event->read_size)
3965 WARN_ON_ONCE(event->ctx->parent_ctx);
3966 if (read_format & PERF_FORMAT_GROUP)
3967 ret = perf_event_read_group(event, read_format, buf);
3969 ret = perf_event_read_one(event, read_format, buf);
3975 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3977 struct perf_event *event = file->private_data;
3978 struct perf_event_context *ctx;
3981 ctx = perf_event_ctx_lock(event);
3982 ret = perf_read_hw(event, buf, count);
3983 perf_event_ctx_unlock(event, ctx);
3988 static unsigned int perf_poll(struct file *file, poll_table *wait)
3990 struct perf_event *event = file->private_data;
3991 struct ring_buffer *rb;
3992 unsigned int events = POLLHUP;
3994 poll_wait(file, &event->waitq, wait);
3996 if (is_event_hup(event))
4000 * Pin the event->rb by taking event->mmap_mutex; otherwise
4001 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4003 mutex_lock(&event->mmap_mutex);
4006 events = atomic_xchg(&rb->poll, 0);
4007 mutex_unlock(&event->mmap_mutex);
4011 static void _perf_event_reset(struct perf_event *event)
4013 (void)perf_event_read(event);
4014 local64_set(&event->count, 0);
4015 perf_event_update_userpage(event);
4019 * Holding the top-level event's child_mutex means that any
4020 * descendant process that has inherited this event will block
4021 * in sync_child_event if it goes to exit, thus satisfying the
4022 * task existence requirements of perf_event_enable/disable.
4024 static void perf_event_for_each_child(struct perf_event *event,
4025 void (*func)(struct perf_event *))
4027 struct perf_event *child;
4029 WARN_ON_ONCE(event->ctx->parent_ctx);
4031 mutex_lock(&event->child_mutex);
4033 list_for_each_entry(child, &event->child_list, child_list)
4035 mutex_unlock(&event->child_mutex);
4038 static void perf_event_for_each(struct perf_event *event,
4039 void (*func)(struct perf_event *))
4041 struct perf_event_context *ctx = event->ctx;
4042 struct perf_event *sibling;
4044 lockdep_assert_held(&ctx->mutex);
4046 event = event->group_leader;
4048 perf_event_for_each_child(event, func);
4049 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4050 perf_event_for_each_child(sibling, func);
4053 struct period_event {
4054 struct perf_event *event;
4058 static int __perf_event_period(void *info)
4060 struct period_event *pe = info;
4061 struct perf_event *event = pe->event;
4062 struct perf_event_context *ctx = event->ctx;
4063 u64 value = pe->value;
4066 raw_spin_lock(&ctx->lock);
4067 if (event->attr.freq) {
4068 event->attr.sample_freq = value;
4070 event->attr.sample_period = value;
4071 event->hw.sample_period = value;
4074 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4076 perf_pmu_disable(ctx->pmu);
4077 event->pmu->stop(event, PERF_EF_UPDATE);
4080 local64_set(&event->hw.period_left, 0);
4083 event->pmu->start(event, PERF_EF_RELOAD);
4084 perf_pmu_enable(ctx->pmu);
4086 raw_spin_unlock(&ctx->lock);
4091 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4093 struct period_event pe = { .event = event, };
4094 struct perf_event_context *ctx = event->ctx;
4095 struct task_struct *task;
4098 if (!is_sampling_event(event))
4101 if (copy_from_user(&value, arg, sizeof(value)))
4107 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4114 cpu_function_call(event->cpu, __perf_event_period, &pe);
4119 if (!task_function_call(task, __perf_event_period, &pe))
4122 raw_spin_lock_irq(&ctx->lock);
4123 if (ctx->is_active) {
4124 raw_spin_unlock_irq(&ctx->lock);
4129 __perf_event_period(&pe);
4130 raw_spin_unlock_irq(&ctx->lock);
4135 static const struct file_operations perf_fops;
4137 static inline int perf_fget_light(int fd, struct fd *p)
4139 struct fd f = fdget(fd);
4143 if (f.file->f_op != &perf_fops) {
4151 static int perf_event_set_output(struct perf_event *event,
4152 struct perf_event *output_event);
4153 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4154 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4156 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4158 void (*func)(struct perf_event *);
4162 case PERF_EVENT_IOC_ENABLE:
4163 func = _perf_event_enable;
4165 case PERF_EVENT_IOC_DISABLE:
4166 func = _perf_event_disable;
4168 case PERF_EVENT_IOC_RESET:
4169 func = _perf_event_reset;
4172 case PERF_EVENT_IOC_REFRESH:
4173 return _perf_event_refresh(event, arg);
4175 case PERF_EVENT_IOC_PERIOD:
4176 return perf_event_period(event, (u64 __user *)arg);
4178 case PERF_EVENT_IOC_ID:
4180 u64 id = primary_event_id(event);
4182 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4187 case PERF_EVENT_IOC_SET_OUTPUT:
4191 struct perf_event *output_event;
4193 ret = perf_fget_light(arg, &output);
4196 output_event = output.file->private_data;
4197 ret = perf_event_set_output(event, output_event);
4200 ret = perf_event_set_output(event, NULL);
4205 case PERF_EVENT_IOC_SET_FILTER:
4206 return perf_event_set_filter(event, (void __user *)arg);
4208 case PERF_EVENT_IOC_SET_BPF:
4209 return perf_event_set_bpf_prog(event, arg);
4215 if (flags & PERF_IOC_FLAG_GROUP)
4216 perf_event_for_each(event, func);
4218 perf_event_for_each_child(event, func);
4223 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4225 struct perf_event *event = file->private_data;
4226 struct perf_event_context *ctx;
4229 ctx = perf_event_ctx_lock(event);
4230 ret = _perf_ioctl(event, cmd, arg);
4231 perf_event_ctx_unlock(event, ctx);
4236 #ifdef CONFIG_COMPAT
4237 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4240 switch (_IOC_NR(cmd)) {
4241 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4242 case _IOC_NR(PERF_EVENT_IOC_ID):
4243 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4244 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4245 cmd &= ~IOCSIZE_MASK;
4246 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4250 return perf_ioctl(file, cmd, arg);
4253 # define perf_compat_ioctl NULL
4256 int perf_event_task_enable(void)
4258 struct perf_event_context *ctx;
4259 struct perf_event *event;
4261 mutex_lock(¤t->perf_event_mutex);
4262 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4263 ctx = perf_event_ctx_lock(event);
4264 perf_event_for_each_child(event, _perf_event_enable);
4265 perf_event_ctx_unlock(event, ctx);
4267 mutex_unlock(¤t->perf_event_mutex);
4272 int perf_event_task_disable(void)
4274 struct perf_event_context *ctx;
4275 struct perf_event *event;
4277 mutex_lock(¤t->perf_event_mutex);
4278 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4279 ctx = perf_event_ctx_lock(event);
4280 perf_event_for_each_child(event, _perf_event_disable);
4281 perf_event_ctx_unlock(event, ctx);
4283 mutex_unlock(¤t->perf_event_mutex);
4288 static int perf_event_index(struct perf_event *event)
4290 if (event->hw.state & PERF_HES_STOPPED)
4293 if (event->state != PERF_EVENT_STATE_ACTIVE)
4296 return event->pmu->event_idx(event);
4299 static void calc_timer_values(struct perf_event *event,
4306 *now = perf_clock();
4307 ctx_time = event->shadow_ctx_time + *now;
4308 *enabled = ctx_time - event->tstamp_enabled;
4309 *running = ctx_time - event->tstamp_running;
4312 static void perf_event_init_userpage(struct perf_event *event)
4314 struct perf_event_mmap_page *userpg;
4315 struct ring_buffer *rb;
4318 rb = rcu_dereference(event->rb);
4322 userpg = rb->user_page;
4324 /* Allow new userspace to detect that bit 0 is deprecated */
4325 userpg->cap_bit0_is_deprecated = 1;
4326 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4327 userpg->data_offset = PAGE_SIZE;
4328 userpg->data_size = perf_data_size(rb);
4334 void __weak arch_perf_update_userpage(
4335 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4340 * Callers need to ensure there can be no nesting of this function, otherwise
4341 * the seqlock logic goes bad. We can not serialize this because the arch
4342 * code calls this from NMI context.
4344 void perf_event_update_userpage(struct perf_event *event)
4346 struct perf_event_mmap_page *userpg;
4347 struct ring_buffer *rb;
4348 u64 enabled, running, now;
4351 rb = rcu_dereference(event->rb);
4356 * compute total_time_enabled, total_time_running
4357 * based on snapshot values taken when the event
4358 * was last scheduled in.
4360 * we cannot simply called update_context_time()
4361 * because of locking issue as we can be called in
4364 calc_timer_values(event, &now, &enabled, &running);
4366 userpg = rb->user_page;
4368 * Disable preemption so as to not let the corresponding user-space
4369 * spin too long if we get preempted.
4374 userpg->index = perf_event_index(event);
4375 userpg->offset = perf_event_count(event);
4377 userpg->offset -= local64_read(&event->hw.prev_count);
4379 userpg->time_enabled = enabled +
4380 atomic64_read(&event->child_total_time_enabled);
4382 userpg->time_running = running +
4383 atomic64_read(&event->child_total_time_running);
4385 arch_perf_update_userpage(event, userpg, now);
4394 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4396 struct perf_event *event = vma->vm_file->private_data;
4397 struct ring_buffer *rb;
4398 int ret = VM_FAULT_SIGBUS;
4400 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4401 if (vmf->pgoff == 0)
4407 rb = rcu_dereference(event->rb);
4411 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4414 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4418 get_page(vmf->page);
4419 vmf->page->mapping = vma->vm_file->f_mapping;
4420 vmf->page->index = vmf->pgoff;
4429 static void ring_buffer_attach(struct perf_event *event,
4430 struct ring_buffer *rb)
4432 struct ring_buffer *old_rb = NULL;
4433 unsigned long flags;
4437 * Should be impossible, we set this when removing
4438 * event->rb_entry and wait/clear when adding event->rb_entry.
4440 WARN_ON_ONCE(event->rcu_pending);
4443 spin_lock_irqsave(&old_rb->event_lock, flags);
4444 list_del_rcu(&event->rb_entry);
4445 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4447 event->rcu_batches = get_state_synchronize_rcu();
4448 event->rcu_pending = 1;
4452 if (event->rcu_pending) {
4453 cond_synchronize_rcu(event->rcu_batches);
4454 event->rcu_pending = 0;
4457 spin_lock_irqsave(&rb->event_lock, flags);
4458 list_add_rcu(&event->rb_entry, &rb->event_list);
4459 spin_unlock_irqrestore(&rb->event_lock, flags);
4462 rcu_assign_pointer(event->rb, rb);
4465 ring_buffer_put(old_rb);
4467 * Since we detached before setting the new rb, so that we
4468 * could attach the new rb, we could have missed a wakeup.
4471 wake_up_all(&event->waitq);
4475 static void ring_buffer_wakeup(struct perf_event *event)
4477 struct ring_buffer *rb;
4480 rb = rcu_dereference(event->rb);
4482 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4483 wake_up_all(&event->waitq);
4488 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4490 struct ring_buffer *rb;
4493 rb = rcu_dereference(event->rb);
4495 if (!atomic_inc_not_zero(&rb->refcount))
4503 void ring_buffer_put(struct ring_buffer *rb)
4505 if (!atomic_dec_and_test(&rb->refcount))
4508 WARN_ON_ONCE(!list_empty(&rb->event_list));
4510 call_rcu(&rb->rcu_head, rb_free_rcu);
4513 static void perf_mmap_open(struct vm_area_struct *vma)
4515 struct perf_event *event = vma->vm_file->private_data;
4517 atomic_inc(&event->mmap_count);
4518 atomic_inc(&event->rb->mmap_count);
4521 atomic_inc(&event->rb->aux_mmap_count);
4523 if (event->pmu->event_mapped)
4524 event->pmu->event_mapped(event);
4528 * A buffer can be mmap()ed multiple times; either directly through the same
4529 * event, or through other events by use of perf_event_set_output().
4531 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4532 * the buffer here, where we still have a VM context. This means we need
4533 * to detach all events redirecting to us.
4535 static void perf_mmap_close(struct vm_area_struct *vma)
4537 struct perf_event *event = vma->vm_file->private_data;
4539 struct ring_buffer *rb = ring_buffer_get(event);
4540 struct user_struct *mmap_user = rb->mmap_user;
4541 int mmap_locked = rb->mmap_locked;
4542 unsigned long size = perf_data_size(rb);
4544 if (event->pmu->event_unmapped)
4545 event->pmu->event_unmapped(event);
4548 * rb->aux_mmap_count will always drop before rb->mmap_count and
4549 * event->mmap_count, so it is ok to use event->mmap_mutex to
4550 * serialize with perf_mmap here.
4552 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4553 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4554 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4555 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4558 mutex_unlock(&event->mmap_mutex);
4561 atomic_dec(&rb->mmap_count);
4563 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4566 ring_buffer_attach(event, NULL);
4567 mutex_unlock(&event->mmap_mutex);
4569 /* If there's still other mmap()s of this buffer, we're done. */
4570 if (atomic_read(&rb->mmap_count))
4574 * No other mmap()s, detach from all other events that might redirect
4575 * into the now unreachable buffer. Somewhat complicated by the
4576 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4580 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4581 if (!atomic_long_inc_not_zero(&event->refcount)) {
4583 * This event is en-route to free_event() which will
4584 * detach it and remove it from the list.
4590 mutex_lock(&event->mmap_mutex);
4592 * Check we didn't race with perf_event_set_output() which can
4593 * swizzle the rb from under us while we were waiting to
4594 * acquire mmap_mutex.
4596 * If we find a different rb; ignore this event, a next
4597 * iteration will no longer find it on the list. We have to
4598 * still restart the iteration to make sure we're not now
4599 * iterating the wrong list.
4601 if (event->rb == rb)
4602 ring_buffer_attach(event, NULL);
4604 mutex_unlock(&event->mmap_mutex);
4608 * Restart the iteration; either we're on the wrong list or
4609 * destroyed its integrity by doing a deletion.
4616 * It could be there's still a few 0-ref events on the list; they'll
4617 * get cleaned up by free_event() -- they'll also still have their
4618 * ref on the rb and will free it whenever they are done with it.
4620 * Aside from that, this buffer is 'fully' detached and unmapped,
4621 * undo the VM accounting.
4624 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4625 vma->vm_mm->pinned_vm -= mmap_locked;
4626 free_uid(mmap_user);
4629 ring_buffer_put(rb); /* could be last */
4632 static const struct vm_operations_struct perf_mmap_vmops = {
4633 .open = perf_mmap_open,
4634 .close = perf_mmap_close, /* non mergable */
4635 .fault = perf_mmap_fault,
4636 .page_mkwrite = perf_mmap_fault,
4639 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4641 struct perf_event *event = file->private_data;
4642 unsigned long user_locked, user_lock_limit;
4643 struct user_struct *user = current_user();
4644 unsigned long locked, lock_limit;
4645 struct ring_buffer *rb = NULL;
4646 unsigned long vma_size;
4647 unsigned long nr_pages;
4648 long user_extra = 0, extra = 0;
4649 int ret = 0, flags = 0;
4652 * Don't allow mmap() of inherited per-task counters. This would
4653 * create a performance issue due to all children writing to the
4656 if (event->cpu == -1 && event->attr.inherit)
4659 if (!(vma->vm_flags & VM_SHARED))
4662 vma_size = vma->vm_end - vma->vm_start;
4664 if (vma->vm_pgoff == 0) {
4665 nr_pages = (vma_size / PAGE_SIZE) - 1;
4668 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4669 * mapped, all subsequent mappings should have the same size
4670 * and offset. Must be above the normal perf buffer.
4672 u64 aux_offset, aux_size;
4677 nr_pages = vma_size / PAGE_SIZE;
4679 mutex_lock(&event->mmap_mutex);
4686 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4687 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4689 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4692 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4695 /* already mapped with a different offset */
4696 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4699 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4702 /* already mapped with a different size */
4703 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4706 if (!is_power_of_2(nr_pages))
4709 if (!atomic_inc_not_zero(&rb->mmap_count))
4712 if (rb_has_aux(rb)) {
4713 atomic_inc(&rb->aux_mmap_count);
4718 atomic_set(&rb->aux_mmap_count, 1);
4719 user_extra = nr_pages;
4725 * If we have rb pages ensure they're a power-of-two number, so we
4726 * can do bitmasks instead of modulo.
4728 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4731 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4734 WARN_ON_ONCE(event->ctx->parent_ctx);
4736 mutex_lock(&event->mmap_mutex);
4738 if (event->rb->nr_pages != nr_pages) {
4743 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4745 * Raced against perf_mmap_close() through
4746 * perf_event_set_output(). Try again, hope for better
4749 mutex_unlock(&event->mmap_mutex);
4756 user_extra = nr_pages + 1;
4759 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4762 * Increase the limit linearly with more CPUs:
4764 user_lock_limit *= num_online_cpus();
4766 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4768 if (user_locked > user_lock_limit)
4769 extra = user_locked - user_lock_limit;
4771 lock_limit = rlimit(RLIMIT_MEMLOCK);
4772 lock_limit >>= PAGE_SHIFT;
4773 locked = vma->vm_mm->pinned_vm + extra;
4775 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4776 !capable(CAP_IPC_LOCK)) {
4781 WARN_ON(!rb && event->rb);
4783 if (vma->vm_flags & VM_WRITE)
4784 flags |= RING_BUFFER_WRITABLE;
4787 rb = rb_alloc(nr_pages,
4788 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4796 atomic_set(&rb->mmap_count, 1);
4797 rb->mmap_user = get_current_user();
4798 rb->mmap_locked = extra;
4800 ring_buffer_attach(event, rb);
4802 perf_event_init_userpage(event);
4803 perf_event_update_userpage(event);
4805 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4806 event->attr.aux_watermark, flags);
4808 rb->aux_mmap_locked = extra;
4813 atomic_long_add(user_extra, &user->locked_vm);
4814 vma->vm_mm->pinned_vm += extra;
4816 atomic_inc(&event->mmap_count);
4818 atomic_dec(&rb->mmap_count);
4821 mutex_unlock(&event->mmap_mutex);
4824 * Since pinned accounting is per vm we cannot allow fork() to copy our
4827 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4828 vma->vm_ops = &perf_mmap_vmops;
4830 if (event->pmu->event_mapped)
4831 event->pmu->event_mapped(event);
4836 static int perf_fasync(int fd, struct file *filp, int on)
4838 struct inode *inode = file_inode(filp);
4839 struct perf_event *event = filp->private_data;
4842 mutex_lock(&inode->i_mutex);
4843 retval = fasync_helper(fd, filp, on, &event->fasync);
4844 mutex_unlock(&inode->i_mutex);
4852 static const struct file_operations perf_fops = {
4853 .llseek = no_llseek,
4854 .release = perf_release,
4857 .unlocked_ioctl = perf_ioctl,
4858 .compat_ioctl = perf_compat_ioctl,
4860 .fasync = perf_fasync,
4866 * If there's data, ensure we set the poll() state and publish everything
4867 * to user-space before waking everybody up.
4870 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4872 /* only the parent has fasync state */
4874 event = event->parent;
4875 return &event->fasync;
4878 void perf_event_wakeup(struct perf_event *event)
4880 ring_buffer_wakeup(event);
4882 if (event->pending_kill) {
4883 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4884 event->pending_kill = 0;
4888 static void perf_pending_event(struct irq_work *entry)
4890 struct perf_event *event = container_of(entry,
4891 struct perf_event, pending);
4894 rctx = perf_swevent_get_recursion_context();
4896 * If we 'fail' here, that's OK, it means recursion is already disabled
4897 * and we won't recurse 'further'.
4900 if (event->pending_disable) {
4901 event->pending_disable = 0;
4902 __perf_event_disable(event);
4905 if (event->pending_wakeup) {
4906 event->pending_wakeup = 0;
4907 perf_event_wakeup(event);
4911 perf_swevent_put_recursion_context(rctx);
4915 * We assume there is only KVM supporting the callbacks.
4916 * Later on, we might change it to a list if there is
4917 * another virtualization implementation supporting the callbacks.
4919 struct perf_guest_info_callbacks *perf_guest_cbs;
4921 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4923 perf_guest_cbs = cbs;
4926 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4928 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4930 perf_guest_cbs = NULL;
4933 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4936 perf_output_sample_regs(struct perf_output_handle *handle,
4937 struct pt_regs *regs, u64 mask)
4941 for_each_set_bit(bit, (const unsigned long *) &mask,
4942 sizeof(mask) * BITS_PER_BYTE) {
4945 val = perf_reg_value(regs, bit);
4946 perf_output_put(handle, val);
4950 static void perf_sample_regs_user(struct perf_regs *regs_user,
4951 struct pt_regs *regs,
4952 struct pt_regs *regs_user_copy)
4954 if (user_mode(regs)) {
4955 regs_user->abi = perf_reg_abi(current);
4956 regs_user->regs = regs;
4957 } else if (current->mm) {
4958 perf_get_regs_user(regs_user, regs, regs_user_copy);
4960 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
4961 regs_user->regs = NULL;
4965 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
4966 struct pt_regs *regs)
4968 regs_intr->regs = regs;
4969 regs_intr->abi = perf_reg_abi(current);
4974 * Get remaining task size from user stack pointer.
4976 * It'd be better to take stack vma map and limit this more
4977 * precisly, but there's no way to get it safely under interrupt,
4978 * so using TASK_SIZE as limit.
4980 static u64 perf_ustack_task_size(struct pt_regs *regs)
4982 unsigned long addr = perf_user_stack_pointer(regs);
4984 if (!addr || addr >= TASK_SIZE)
4987 return TASK_SIZE - addr;
4991 perf_sample_ustack_size(u16 stack_size, u16 header_size,
4992 struct pt_regs *regs)
4996 /* No regs, no stack pointer, no dump. */
5001 * Check if we fit in with the requested stack size into the:
5003 * If we don't, we limit the size to the TASK_SIZE.
5005 * - remaining sample size
5006 * If we don't, we customize the stack size to
5007 * fit in to the remaining sample size.
5010 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5011 stack_size = min(stack_size, (u16) task_size);
5013 /* Current header size plus static size and dynamic size. */
5014 header_size += 2 * sizeof(u64);
5016 /* Do we fit in with the current stack dump size? */
5017 if ((u16) (header_size + stack_size) < header_size) {
5019 * If we overflow the maximum size for the sample,
5020 * we customize the stack dump size to fit in.
5022 stack_size = USHRT_MAX - header_size - sizeof(u64);
5023 stack_size = round_up(stack_size, sizeof(u64));
5030 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5031 struct pt_regs *regs)
5033 /* Case of a kernel thread, nothing to dump */
5036 perf_output_put(handle, size);
5045 * - the size requested by user or the best one we can fit
5046 * in to the sample max size
5048 * - user stack dump data
5050 * - the actual dumped size
5054 perf_output_put(handle, dump_size);
5057 sp = perf_user_stack_pointer(regs);
5058 rem = __output_copy_user(handle, (void *) sp, dump_size);
5059 dyn_size = dump_size - rem;
5061 perf_output_skip(handle, rem);
5064 perf_output_put(handle, dyn_size);
5068 static void __perf_event_header__init_id(struct perf_event_header *header,
5069 struct perf_sample_data *data,
5070 struct perf_event *event)
5072 u64 sample_type = event->attr.sample_type;
5074 data->type = sample_type;
5075 header->size += event->id_header_size;
5077 if (sample_type & PERF_SAMPLE_TID) {
5078 /* namespace issues */
5079 data->tid_entry.pid = perf_event_pid(event, current);
5080 data->tid_entry.tid = perf_event_tid(event, current);
5083 if (sample_type & PERF_SAMPLE_TIME)
5084 data->time = perf_event_clock(event);
5086 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5087 data->id = primary_event_id(event);
5089 if (sample_type & PERF_SAMPLE_STREAM_ID)
5090 data->stream_id = event->id;
5092 if (sample_type & PERF_SAMPLE_CPU) {
5093 data->cpu_entry.cpu = raw_smp_processor_id();
5094 data->cpu_entry.reserved = 0;
5098 void perf_event_header__init_id(struct perf_event_header *header,
5099 struct perf_sample_data *data,
5100 struct perf_event *event)
5102 if (event->attr.sample_id_all)
5103 __perf_event_header__init_id(header, data, event);
5106 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5107 struct perf_sample_data *data)
5109 u64 sample_type = data->type;
5111 if (sample_type & PERF_SAMPLE_TID)
5112 perf_output_put(handle, data->tid_entry);
5114 if (sample_type & PERF_SAMPLE_TIME)
5115 perf_output_put(handle, data->time);
5117 if (sample_type & PERF_SAMPLE_ID)
5118 perf_output_put(handle, data->id);
5120 if (sample_type & PERF_SAMPLE_STREAM_ID)
5121 perf_output_put(handle, data->stream_id);
5123 if (sample_type & PERF_SAMPLE_CPU)
5124 perf_output_put(handle, data->cpu_entry);
5126 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5127 perf_output_put(handle, data->id);
5130 void perf_event__output_id_sample(struct perf_event *event,
5131 struct perf_output_handle *handle,
5132 struct perf_sample_data *sample)
5134 if (event->attr.sample_id_all)
5135 __perf_event__output_id_sample(handle, sample);
5138 static void perf_output_read_one(struct perf_output_handle *handle,
5139 struct perf_event *event,
5140 u64 enabled, u64 running)
5142 u64 read_format = event->attr.read_format;
5146 values[n++] = perf_event_count(event);
5147 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5148 values[n++] = enabled +
5149 atomic64_read(&event->child_total_time_enabled);
5151 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5152 values[n++] = running +
5153 atomic64_read(&event->child_total_time_running);
5155 if (read_format & PERF_FORMAT_ID)
5156 values[n++] = primary_event_id(event);
5158 __output_copy(handle, values, n * sizeof(u64));
5162 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5164 static void perf_output_read_group(struct perf_output_handle *handle,
5165 struct perf_event *event,
5166 u64 enabled, u64 running)
5168 struct perf_event *leader = event->group_leader, *sub;
5169 u64 read_format = event->attr.read_format;
5173 values[n++] = 1 + leader->nr_siblings;
5175 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5176 values[n++] = enabled;
5178 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5179 values[n++] = running;
5181 if (leader != event)
5182 leader->pmu->read(leader);
5184 values[n++] = perf_event_count(leader);
5185 if (read_format & PERF_FORMAT_ID)
5186 values[n++] = primary_event_id(leader);
5188 __output_copy(handle, values, n * sizeof(u64));
5190 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5193 if ((sub != event) &&
5194 (sub->state == PERF_EVENT_STATE_ACTIVE))
5195 sub->pmu->read(sub);
5197 values[n++] = perf_event_count(sub);
5198 if (read_format & PERF_FORMAT_ID)
5199 values[n++] = primary_event_id(sub);
5201 __output_copy(handle, values, n * sizeof(u64));
5205 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5206 PERF_FORMAT_TOTAL_TIME_RUNNING)
5208 static void perf_output_read(struct perf_output_handle *handle,
5209 struct perf_event *event)
5211 u64 enabled = 0, running = 0, now;
5212 u64 read_format = event->attr.read_format;
5215 * compute total_time_enabled, total_time_running
5216 * based on snapshot values taken when the event
5217 * was last scheduled in.
5219 * we cannot simply called update_context_time()
5220 * because of locking issue as we are called in
5223 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5224 calc_timer_values(event, &now, &enabled, &running);
5226 if (event->attr.read_format & PERF_FORMAT_GROUP)
5227 perf_output_read_group(handle, event, enabled, running);
5229 perf_output_read_one(handle, event, enabled, running);
5232 void perf_output_sample(struct perf_output_handle *handle,
5233 struct perf_event_header *header,
5234 struct perf_sample_data *data,
5235 struct perf_event *event)
5237 u64 sample_type = data->type;
5239 perf_output_put(handle, *header);
5241 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5242 perf_output_put(handle, data->id);
5244 if (sample_type & PERF_SAMPLE_IP)
5245 perf_output_put(handle, data->ip);
5247 if (sample_type & PERF_SAMPLE_TID)
5248 perf_output_put(handle, data->tid_entry);
5250 if (sample_type & PERF_SAMPLE_TIME)
5251 perf_output_put(handle, data->time);
5253 if (sample_type & PERF_SAMPLE_ADDR)
5254 perf_output_put(handle, data->addr);
5256 if (sample_type & PERF_SAMPLE_ID)
5257 perf_output_put(handle, data->id);
5259 if (sample_type & PERF_SAMPLE_STREAM_ID)
5260 perf_output_put(handle, data->stream_id);
5262 if (sample_type & PERF_SAMPLE_CPU)
5263 perf_output_put(handle, data->cpu_entry);
5265 if (sample_type & PERF_SAMPLE_PERIOD)
5266 perf_output_put(handle, data->period);
5268 if (sample_type & PERF_SAMPLE_READ)
5269 perf_output_read(handle, event);
5271 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5272 if (data->callchain) {
5275 if (data->callchain)
5276 size += data->callchain->nr;
5278 size *= sizeof(u64);
5280 __output_copy(handle, data->callchain, size);
5283 perf_output_put(handle, nr);
5287 if (sample_type & PERF_SAMPLE_RAW) {
5289 perf_output_put(handle, data->raw->size);
5290 __output_copy(handle, data->raw->data,
5297 .size = sizeof(u32),
5300 perf_output_put(handle, raw);
5304 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5305 if (data->br_stack) {
5308 size = data->br_stack->nr
5309 * sizeof(struct perf_branch_entry);
5311 perf_output_put(handle, data->br_stack->nr);
5312 perf_output_copy(handle, data->br_stack->entries, size);
5315 * we always store at least the value of nr
5318 perf_output_put(handle, nr);
5322 if (sample_type & PERF_SAMPLE_REGS_USER) {
5323 u64 abi = data->regs_user.abi;
5326 * If there are no regs to dump, notice it through
5327 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5329 perf_output_put(handle, abi);
5332 u64 mask = event->attr.sample_regs_user;
5333 perf_output_sample_regs(handle,
5334 data->regs_user.regs,
5339 if (sample_type & PERF_SAMPLE_STACK_USER) {
5340 perf_output_sample_ustack(handle,
5341 data->stack_user_size,
5342 data->regs_user.regs);
5345 if (sample_type & PERF_SAMPLE_WEIGHT)
5346 perf_output_put(handle, data->weight);
5348 if (sample_type & PERF_SAMPLE_DATA_SRC)
5349 perf_output_put(handle, data->data_src.val);
5351 if (sample_type & PERF_SAMPLE_TRANSACTION)
5352 perf_output_put(handle, data->txn);
5354 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5355 u64 abi = data->regs_intr.abi;
5357 * If there are no regs to dump, notice it through
5358 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5360 perf_output_put(handle, abi);
5363 u64 mask = event->attr.sample_regs_intr;
5365 perf_output_sample_regs(handle,
5366 data->regs_intr.regs,
5371 if (!event->attr.watermark) {
5372 int wakeup_events = event->attr.wakeup_events;
5374 if (wakeup_events) {
5375 struct ring_buffer *rb = handle->rb;
5376 int events = local_inc_return(&rb->events);
5378 if (events >= wakeup_events) {
5379 local_sub(wakeup_events, &rb->events);
5380 local_inc(&rb->wakeup);
5386 void perf_prepare_sample(struct perf_event_header *header,
5387 struct perf_sample_data *data,
5388 struct perf_event *event,
5389 struct pt_regs *regs)
5391 u64 sample_type = event->attr.sample_type;
5393 header->type = PERF_RECORD_SAMPLE;
5394 header->size = sizeof(*header) + event->header_size;
5397 header->misc |= perf_misc_flags(regs);
5399 __perf_event_header__init_id(header, data, event);
5401 if (sample_type & PERF_SAMPLE_IP)
5402 data->ip = perf_instruction_pointer(regs);
5404 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5407 data->callchain = perf_callchain(event, regs);
5409 if (data->callchain)
5410 size += data->callchain->nr;
5412 header->size += size * sizeof(u64);
5415 if (sample_type & PERF_SAMPLE_RAW) {
5416 int size = sizeof(u32);
5419 size += data->raw->size;
5421 size += sizeof(u32);
5423 WARN_ON_ONCE(size & (sizeof(u64)-1));
5424 header->size += size;
5427 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5428 int size = sizeof(u64); /* nr */
5429 if (data->br_stack) {
5430 size += data->br_stack->nr
5431 * sizeof(struct perf_branch_entry);
5433 header->size += size;
5436 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5437 perf_sample_regs_user(&data->regs_user, regs,
5438 &data->regs_user_copy);
5440 if (sample_type & PERF_SAMPLE_REGS_USER) {
5441 /* regs dump ABI info */
5442 int size = sizeof(u64);
5444 if (data->regs_user.regs) {
5445 u64 mask = event->attr.sample_regs_user;
5446 size += hweight64(mask) * sizeof(u64);
5449 header->size += size;
5452 if (sample_type & PERF_SAMPLE_STACK_USER) {
5454 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5455 * processed as the last one or have additional check added
5456 * in case new sample type is added, because we could eat
5457 * up the rest of the sample size.
5459 u16 stack_size = event->attr.sample_stack_user;
5460 u16 size = sizeof(u64);
5462 stack_size = perf_sample_ustack_size(stack_size, header->size,
5463 data->regs_user.regs);
5466 * If there is something to dump, add space for the dump
5467 * itself and for the field that tells the dynamic size,
5468 * which is how many have been actually dumped.
5471 size += sizeof(u64) + stack_size;
5473 data->stack_user_size = stack_size;
5474 header->size += size;
5477 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5478 /* regs dump ABI info */
5479 int size = sizeof(u64);
5481 perf_sample_regs_intr(&data->regs_intr, regs);
5483 if (data->regs_intr.regs) {
5484 u64 mask = event->attr.sample_regs_intr;
5486 size += hweight64(mask) * sizeof(u64);
5489 header->size += size;
5493 void perf_event_output(struct perf_event *event,
5494 struct perf_sample_data *data,
5495 struct pt_regs *regs)
5497 struct perf_output_handle handle;
5498 struct perf_event_header header;
5500 /* protect the callchain buffers */
5503 perf_prepare_sample(&header, data, event, regs);
5505 if (perf_output_begin(&handle, event, header.size))
5508 perf_output_sample(&handle, &header, data, event);
5510 perf_output_end(&handle);
5520 struct perf_read_event {
5521 struct perf_event_header header;
5528 perf_event_read_event(struct perf_event *event,
5529 struct task_struct *task)
5531 struct perf_output_handle handle;
5532 struct perf_sample_data sample;
5533 struct perf_read_event read_event = {
5535 .type = PERF_RECORD_READ,
5537 .size = sizeof(read_event) + event->read_size,
5539 .pid = perf_event_pid(event, task),
5540 .tid = perf_event_tid(event, task),
5544 perf_event_header__init_id(&read_event.header, &sample, event);
5545 ret = perf_output_begin(&handle, event, read_event.header.size);
5549 perf_output_put(&handle, read_event);
5550 perf_output_read(&handle, event);
5551 perf_event__output_id_sample(event, &handle, &sample);
5553 perf_output_end(&handle);
5556 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5559 perf_event_aux_ctx(struct perf_event_context *ctx,
5560 perf_event_aux_output_cb output,
5563 struct perf_event *event;
5565 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5566 if (event->state < PERF_EVENT_STATE_INACTIVE)
5568 if (!event_filter_match(event))
5570 output(event, data);
5575 perf_event_aux(perf_event_aux_output_cb output, void *data,
5576 struct perf_event_context *task_ctx)
5578 struct perf_cpu_context *cpuctx;
5579 struct perf_event_context *ctx;
5584 list_for_each_entry_rcu(pmu, &pmus, entry) {
5585 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5586 if (cpuctx->unique_pmu != pmu)
5588 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5591 ctxn = pmu->task_ctx_nr;
5594 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5596 perf_event_aux_ctx(ctx, output, data);
5598 put_cpu_ptr(pmu->pmu_cpu_context);
5603 perf_event_aux_ctx(task_ctx, output, data);
5610 * task tracking -- fork/exit
5612 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5615 struct perf_task_event {
5616 struct task_struct *task;
5617 struct perf_event_context *task_ctx;
5620 struct perf_event_header header;
5630 static int perf_event_task_match(struct perf_event *event)
5632 return event->attr.comm || event->attr.mmap ||
5633 event->attr.mmap2 || event->attr.mmap_data ||
5637 static void perf_event_task_output(struct perf_event *event,
5640 struct perf_task_event *task_event = data;
5641 struct perf_output_handle handle;
5642 struct perf_sample_data sample;
5643 struct task_struct *task = task_event->task;
5644 int ret, size = task_event->event_id.header.size;
5646 if (!perf_event_task_match(event))
5649 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5651 ret = perf_output_begin(&handle, event,
5652 task_event->event_id.header.size);
5656 task_event->event_id.pid = perf_event_pid(event, task);
5657 task_event->event_id.ppid = perf_event_pid(event, current);
5659 task_event->event_id.tid = perf_event_tid(event, task);
5660 task_event->event_id.ptid = perf_event_tid(event, current);
5662 task_event->event_id.time = perf_event_clock(event);
5664 perf_output_put(&handle, task_event->event_id);
5666 perf_event__output_id_sample(event, &handle, &sample);
5668 perf_output_end(&handle);
5670 task_event->event_id.header.size = size;
5673 static void perf_event_task(struct task_struct *task,
5674 struct perf_event_context *task_ctx,
5677 struct perf_task_event task_event;
5679 if (!atomic_read(&nr_comm_events) &&
5680 !atomic_read(&nr_mmap_events) &&
5681 !atomic_read(&nr_task_events))
5684 task_event = (struct perf_task_event){
5686 .task_ctx = task_ctx,
5689 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5691 .size = sizeof(task_event.event_id),
5701 perf_event_aux(perf_event_task_output,
5706 void perf_event_fork(struct task_struct *task)
5708 perf_event_task(task, NULL, 1);
5715 struct perf_comm_event {
5716 struct task_struct *task;
5721 struct perf_event_header header;
5728 static int perf_event_comm_match(struct perf_event *event)
5730 return event->attr.comm;
5733 static void perf_event_comm_output(struct perf_event *event,
5736 struct perf_comm_event *comm_event = data;
5737 struct perf_output_handle handle;
5738 struct perf_sample_data sample;
5739 int size = comm_event->event_id.header.size;
5742 if (!perf_event_comm_match(event))
5745 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5746 ret = perf_output_begin(&handle, event,
5747 comm_event->event_id.header.size);
5752 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5753 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5755 perf_output_put(&handle, comm_event->event_id);
5756 __output_copy(&handle, comm_event->comm,
5757 comm_event->comm_size);
5759 perf_event__output_id_sample(event, &handle, &sample);
5761 perf_output_end(&handle);
5763 comm_event->event_id.header.size = size;
5766 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5768 char comm[TASK_COMM_LEN];
5771 memset(comm, 0, sizeof(comm));
5772 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5773 size = ALIGN(strlen(comm)+1, sizeof(u64));
5775 comm_event->comm = comm;
5776 comm_event->comm_size = size;
5778 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5780 perf_event_aux(perf_event_comm_output,
5785 void perf_event_comm(struct task_struct *task, bool exec)
5787 struct perf_comm_event comm_event;
5789 if (!atomic_read(&nr_comm_events))
5792 comm_event = (struct perf_comm_event){
5798 .type = PERF_RECORD_COMM,
5799 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5807 perf_event_comm_event(&comm_event);
5814 struct perf_mmap_event {
5815 struct vm_area_struct *vma;
5817 const char *file_name;
5825 struct perf_event_header header;
5835 static int perf_event_mmap_match(struct perf_event *event,
5838 struct perf_mmap_event *mmap_event = data;
5839 struct vm_area_struct *vma = mmap_event->vma;
5840 int executable = vma->vm_flags & VM_EXEC;
5842 return (!executable && event->attr.mmap_data) ||
5843 (executable && (event->attr.mmap || event->attr.mmap2));
5846 static void perf_event_mmap_output(struct perf_event *event,
5849 struct perf_mmap_event *mmap_event = data;
5850 struct perf_output_handle handle;
5851 struct perf_sample_data sample;
5852 int size = mmap_event->event_id.header.size;
5855 if (!perf_event_mmap_match(event, data))
5858 if (event->attr.mmap2) {
5859 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5860 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5861 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5862 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5863 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5864 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5865 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5868 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5869 ret = perf_output_begin(&handle, event,
5870 mmap_event->event_id.header.size);
5874 mmap_event->event_id.pid = perf_event_pid(event, current);
5875 mmap_event->event_id.tid = perf_event_tid(event, current);
5877 perf_output_put(&handle, mmap_event->event_id);
5879 if (event->attr.mmap2) {
5880 perf_output_put(&handle, mmap_event->maj);
5881 perf_output_put(&handle, mmap_event->min);
5882 perf_output_put(&handle, mmap_event->ino);
5883 perf_output_put(&handle, mmap_event->ino_generation);
5884 perf_output_put(&handle, mmap_event->prot);
5885 perf_output_put(&handle, mmap_event->flags);
5888 __output_copy(&handle, mmap_event->file_name,
5889 mmap_event->file_size);
5891 perf_event__output_id_sample(event, &handle, &sample);
5893 perf_output_end(&handle);
5895 mmap_event->event_id.header.size = size;
5898 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5900 struct vm_area_struct *vma = mmap_event->vma;
5901 struct file *file = vma->vm_file;
5902 int maj = 0, min = 0;
5903 u64 ino = 0, gen = 0;
5904 u32 prot = 0, flags = 0;
5911 struct inode *inode;
5914 buf = kmalloc(PATH_MAX, GFP_KERNEL);
5920 * d_path() works from the end of the rb backwards, so we
5921 * need to add enough zero bytes after the string to handle
5922 * the 64bit alignment we do later.
5924 name = file_path(file, buf, PATH_MAX - sizeof(u64));
5929 inode = file_inode(vma->vm_file);
5930 dev = inode->i_sb->s_dev;
5932 gen = inode->i_generation;
5936 if (vma->vm_flags & VM_READ)
5938 if (vma->vm_flags & VM_WRITE)
5940 if (vma->vm_flags & VM_EXEC)
5943 if (vma->vm_flags & VM_MAYSHARE)
5946 flags = MAP_PRIVATE;
5948 if (vma->vm_flags & VM_DENYWRITE)
5949 flags |= MAP_DENYWRITE;
5950 if (vma->vm_flags & VM_MAYEXEC)
5951 flags |= MAP_EXECUTABLE;
5952 if (vma->vm_flags & VM_LOCKED)
5953 flags |= MAP_LOCKED;
5954 if (vma->vm_flags & VM_HUGETLB)
5955 flags |= MAP_HUGETLB;
5959 if (vma->vm_ops && vma->vm_ops->name) {
5960 name = (char *) vma->vm_ops->name(vma);
5965 name = (char *)arch_vma_name(vma);
5969 if (vma->vm_start <= vma->vm_mm->start_brk &&
5970 vma->vm_end >= vma->vm_mm->brk) {
5974 if (vma->vm_start <= vma->vm_mm->start_stack &&
5975 vma->vm_end >= vma->vm_mm->start_stack) {
5985 strlcpy(tmp, name, sizeof(tmp));
5989 * Since our buffer works in 8 byte units we need to align our string
5990 * size to a multiple of 8. However, we must guarantee the tail end is
5991 * zero'd out to avoid leaking random bits to userspace.
5993 size = strlen(name)+1;
5994 while (!IS_ALIGNED(size, sizeof(u64)))
5995 name[size++] = '\0';
5997 mmap_event->file_name = name;
5998 mmap_event->file_size = size;
5999 mmap_event->maj = maj;
6000 mmap_event->min = min;
6001 mmap_event->ino = ino;
6002 mmap_event->ino_generation = gen;
6003 mmap_event->prot = prot;
6004 mmap_event->flags = flags;
6006 if (!(vma->vm_flags & VM_EXEC))
6007 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6009 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6011 perf_event_aux(perf_event_mmap_output,
6018 void perf_event_mmap(struct vm_area_struct *vma)
6020 struct perf_mmap_event mmap_event;
6022 if (!atomic_read(&nr_mmap_events))
6025 mmap_event = (struct perf_mmap_event){
6031 .type = PERF_RECORD_MMAP,
6032 .misc = PERF_RECORD_MISC_USER,
6037 .start = vma->vm_start,
6038 .len = vma->vm_end - vma->vm_start,
6039 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6041 /* .maj (attr_mmap2 only) */
6042 /* .min (attr_mmap2 only) */
6043 /* .ino (attr_mmap2 only) */
6044 /* .ino_generation (attr_mmap2 only) */
6045 /* .prot (attr_mmap2 only) */
6046 /* .flags (attr_mmap2 only) */
6049 perf_event_mmap_event(&mmap_event);
6052 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6053 unsigned long size, u64 flags)
6055 struct perf_output_handle handle;
6056 struct perf_sample_data sample;
6057 struct perf_aux_event {
6058 struct perf_event_header header;
6064 .type = PERF_RECORD_AUX,
6066 .size = sizeof(rec),
6074 perf_event_header__init_id(&rec.header, &sample, event);
6075 ret = perf_output_begin(&handle, event, rec.header.size);
6080 perf_output_put(&handle, rec);
6081 perf_event__output_id_sample(event, &handle, &sample);
6083 perf_output_end(&handle);
6087 * Lost/dropped samples logging
6089 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6091 struct perf_output_handle handle;
6092 struct perf_sample_data sample;
6096 struct perf_event_header header;
6098 } lost_samples_event = {
6100 .type = PERF_RECORD_LOST_SAMPLES,
6102 .size = sizeof(lost_samples_event),
6107 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6109 ret = perf_output_begin(&handle, event,
6110 lost_samples_event.header.size);
6114 perf_output_put(&handle, lost_samples_event);
6115 perf_event__output_id_sample(event, &handle, &sample);
6116 perf_output_end(&handle);
6120 * context_switch tracking
6123 struct perf_switch_event {
6124 struct task_struct *task;
6125 struct task_struct *next_prev;
6128 struct perf_event_header header;
6134 static int perf_event_switch_match(struct perf_event *event)
6136 return event->attr.context_switch;
6139 static void perf_event_switch_output(struct perf_event *event, void *data)
6141 struct perf_switch_event *se = data;
6142 struct perf_output_handle handle;
6143 struct perf_sample_data sample;
6146 if (!perf_event_switch_match(event))
6149 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6150 if (event->ctx->task) {
6151 se->event_id.header.type = PERF_RECORD_SWITCH;
6152 se->event_id.header.size = sizeof(se->event_id.header);
6154 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6155 se->event_id.header.size = sizeof(se->event_id);
6156 se->event_id.next_prev_pid =
6157 perf_event_pid(event, se->next_prev);
6158 se->event_id.next_prev_tid =
6159 perf_event_tid(event, se->next_prev);
6162 perf_event_header__init_id(&se->event_id.header, &sample, event);
6164 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6168 if (event->ctx->task)
6169 perf_output_put(&handle, se->event_id.header);
6171 perf_output_put(&handle, se->event_id);
6173 perf_event__output_id_sample(event, &handle, &sample);
6175 perf_output_end(&handle);
6178 static void perf_event_switch(struct task_struct *task,
6179 struct task_struct *next_prev, bool sched_in)
6181 struct perf_switch_event switch_event;
6183 /* N.B. caller checks nr_switch_events != 0 */
6185 switch_event = (struct perf_switch_event){
6187 .next_prev = next_prev,
6191 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6194 /* .next_prev_pid */
6195 /* .next_prev_tid */
6199 perf_event_aux(perf_event_switch_output,
6205 * IRQ throttle logging
6208 static void perf_log_throttle(struct perf_event *event, int enable)
6210 struct perf_output_handle handle;
6211 struct perf_sample_data sample;
6215 struct perf_event_header header;
6219 } throttle_event = {
6221 .type = PERF_RECORD_THROTTLE,
6223 .size = sizeof(throttle_event),
6225 .time = perf_event_clock(event),
6226 .id = primary_event_id(event),
6227 .stream_id = event->id,
6231 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6233 perf_event_header__init_id(&throttle_event.header, &sample, event);
6235 ret = perf_output_begin(&handle, event,
6236 throttle_event.header.size);
6240 perf_output_put(&handle, throttle_event);
6241 perf_event__output_id_sample(event, &handle, &sample);
6242 perf_output_end(&handle);
6245 static void perf_log_itrace_start(struct perf_event *event)
6247 struct perf_output_handle handle;
6248 struct perf_sample_data sample;
6249 struct perf_aux_event {
6250 struct perf_event_header header;
6257 event = event->parent;
6259 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6260 event->hw.itrace_started)
6263 rec.header.type = PERF_RECORD_ITRACE_START;
6264 rec.header.misc = 0;
6265 rec.header.size = sizeof(rec);
6266 rec.pid = perf_event_pid(event, current);
6267 rec.tid = perf_event_tid(event, current);
6269 perf_event_header__init_id(&rec.header, &sample, event);
6270 ret = perf_output_begin(&handle, event, rec.header.size);
6275 perf_output_put(&handle, rec);
6276 perf_event__output_id_sample(event, &handle, &sample);
6278 perf_output_end(&handle);
6282 * Generic event overflow handling, sampling.
6285 static int __perf_event_overflow(struct perf_event *event,
6286 int throttle, struct perf_sample_data *data,
6287 struct pt_regs *regs)
6289 int events = atomic_read(&event->event_limit);
6290 struct hw_perf_event *hwc = &event->hw;
6295 * Non-sampling counters might still use the PMI to fold short
6296 * hardware counters, ignore those.
6298 if (unlikely(!is_sampling_event(event)))
6301 seq = __this_cpu_read(perf_throttled_seq);
6302 if (seq != hwc->interrupts_seq) {
6303 hwc->interrupts_seq = seq;
6304 hwc->interrupts = 1;
6307 if (unlikely(throttle
6308 && hwc->interrupts >= max_samples_per_tick)) {
6309 __this_cpu_inc(perf_throttled_count);
6310 hwc->interrupts = MAX_INTERRUPTS;
6311 perf_log_throttle(event, 0);
6312 tick_nohz_full_kick();
6317 if (event->attr.freq) {
6318 u64 now = perf_clock();
6319 s64 delta = now - hwc->freq_time_stamp;
6321 hwc->freq_time_stamp = now;
6323 if (delta > 0 && delta < 2*TICK_NSEC)
6324 perf_adjust_period(event, delta, hwc->last_period, true);
6328 * XXX event_limit might not quite work as expected on inherited
6332 event->pending_kill = POLL_IN;
6333 if (events && atomic_dec_and_test(&event->event_limit)) {
6335 event->pending_kill = POLL_HUP;
6336 event->pending_disable = 1;
6337 irq_work_queue(&event->pending);
6340 if (event->overflow_handler)
6341 event->overflow_handler(event, data, regs);
6343 perf_event_output(event, data, regs);
6345 if (*perf_event_fasync(event) && event->pending_kill) {
6346 event->pending_wakeup = 1;
6347 irq_work_queue(&event->pending);
6353 int perf_event_overflow(struct perf_event *event,
6354 struct perf_sample_data *data,
6355 struct pt_regs *regs)
6357 return __perf_event_overflow(event, 1, data, regs);
6361 * Generic software event infrastructure
6364 struct swevent_htable {
6365 struct swevent_hlist *swevent_hlist;
6366 struct mutex hlist_mutex;
6369 /* Recursion avoidance in each contexts */
6370 int recursion[PERF_NR_CONTEXTS];
6372 /* Keeps track of cpu being initialized/exited */
6376 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6379 * We directly increment event->count and keep a second value in
6380 * event->hw.period_left to count intervals. This period event
6381 * is kept in the range [-sample_period, 0] so that we can use the
6385 u64 perf_swevent_set_period(struct perf_event *event)
6387 struct hw_perf_event *hwc = &event->hw;
6388 u64 period = hwc->last_period;
6392 hwc->last_period = hwc->sample_period;
6395 old = val = local64_read(&hwc->period_left);
6399 nr = div64_u64(period + val, period);
6400 offset = nr * period;
6402 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6408 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6409 struct perf_sample_data *data,
6410 struct pt_regs *regs)
6412 struct hw_perf_event *hwc = &event->hw;
6416 overflow = perf_swevent_set_period(event);
6418 if (hwc->interrupts == MAX_INTERRUPTS)
6421 for (; overflow; overflow--) {
6422 if (__perf_event_overflow(event, throttle,
6425 * We inhibit the overflow from happening when
6426 * hwc->interrupts == MAX_INTERRUPTS.
6434 static void perf_swevent_event(struct perf_event *event, u64 nr,
6435 struct perf_sample_data *data,
6436 struct pt_regs *regs)
6438 struct hw_perf_event *hwc = &event->hw;
6440 local64_add(nr, &event->count);
6445 if (!is_sampling_event(event))
6448 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6450 return perf_swevent_overflow(event, 1, data, regs);
6452 data->period = event->hw.last_period;
6454 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6455 return perf_swevent_overflow(event, 1, data, regs);
6457 if (local64_add_negative(nr, &hwc->period_left))
6460 perf_swevent_overflow(event, 0, data, regs);
6463 static int perf_exclude_event(struct perf_event *event,
6464 struct pt_regs *regs)
6466 if (event->hw.state & PERF_HES_STOPPED)
6470 if (event->attr.exclude_user && user_mode(regs))
6473 if (event->attr.exclude_kernel && !user_mode(regs))
6480 static int perf_swevent_match(struct perf_event *event,
6481 enum perf_type_id type,
6483 struct perf_sample_data *data,
6484 struct pt_regs *regs)
6486 if (event->attr.type != type)
6489 if (event->attr.config != event_id)
6492 if (perf_exclude_event(event, regs))
6498 static inline u64 swevent_hash(u64 type, u32 event_id)
6500 u64 val = event_id | (type << 32);
6502 return hash_64(val, SWEVENT_HLIST_BITS);
6505 static inline struct hlist_head *
6506 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6508 u64 hash = swevent_hash(type, event_id);
6510 return &hlist->heads[hash];
6513 /* For the read side: events when they trigger */
6514 static inline struct hlist_head *
6515 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6517 struct swevent_hlist *hlist;
6519 hlist = rcu_dereference(swhash->swevent_hlist);
6523 return __find_swevent_head(hlist, type, event_id);
6526 /* For the event head insertion and removal in the hlist */
6527 static inline struct hlist_head *
6528 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6530 struct swevent_hlist *hlist;
6531 u32 event_id = event->attr.config;
6532 u64 type = event->attr.type;
6535 * Event scheduling is always serialized against hlist allocation
6536 * and release. Which makes the protected version suitable here.
6537 * The context lock guarantees that.
6539 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6540 lockdep_is_held(&event->ctx->lock));
6544 return __find_swevent_head(hlist, type, event_id);
6547 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6549 struct perf_sample_data *data,
6550 struct pt_regs *regs)
6552 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6553 struct perf_event *event;
6554 struct hlist_head *head;
6557 head = find_swevent_head_rcu(swhash, type, event_id);
6561 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6562 if (perf_swevent_match(event, type, event_id, data, regs))
6563 perf_swevent_event(event, nr, data, regs);
6569 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6571 int perf_swevent_get_recursion_context(void)
6573 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6575 return get_recursion_context(swhash->recursion);
6577 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6579 inline void perf_swevent_put_recursion_context(int rctx)
6581 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6583 put_recursion_context(swhash->recursion, rctx);
6586 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6588 struct perf_sample_data data;
6590 if (WARN_ON_ONCE(!regs))
6593 perf_sample_data_init(&data, addr, 0);
6594 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6597 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6601 preempt_disable_notrace();
6602 rctx = perf_swevent_get_recursion_context();
6603 if (unlikely(rctx < 0))
6606 ___perf_sw_event(event_id, nr, regs, addr);
6608 perf_swevent_put_recursion_context(rctx);
6610 preempt_enable_notrace();
6613 static void perf_swevent_read(struct perf_event *event)
6617 static int perf_swevent_add(struct perf_event *event, int flags)
6619 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6620 struct hw_perf_event *hwc = &event->hw;
6621 struct hlist_head *head;
6623 if (is_sampling_event(event)) {
6624 hwc->last_period = hwc->sample_period;
6625 perf_swevent_set_period(event);
6628 hwc->state = !(flags & PERF_EF_START);
6630 head = find_swevent_head(swhash, event);
6633 * We can race with cpu hotplug code. Do not
6634 * WARN if the cpu just got unplugged.
6636 WARN_ON_ONCE(swhash->online);
6640 hlist_add_head_rcu(&event->hlist_entry, head);
6641 perf_event_update_userpage(event);
6646 static void perf_swevent_del(struct perf_event *event, int flags)
6648 hlist_del_rcu(&event->hlist_entry);
6651 static void perf_swevent_start(struct perf_event *event, int flags)
6653 event->hw.state = 0;
6656 static void perf_swevent_stop(struct perf_event *event, int flags)
6658 event->hw.state = PERF_HES_STOPPED;
6661 /* Deref the hlist from the update side */
6662 static inline struct swevent_hlist *
6663 swevent_hlist_deref(struct swevent_htable *swhash)
6665 return rcu_dereference_protected(swhash->swevent_hlist,
6666 lockdep_is_held(&swhash->hlist_mutex));
6669 static void swevent_hlist_release(struct swevent_htable *swhash)
6671 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6676 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6677 kfree_rcu(hlist, rcu_head);
6680 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6682 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6684 mutex_lock(&swhash->hlist_mutex);
6686 if (!--swhash->hlist_refcount)
6687 swevent_hlist_release(swhash);
6689 mutex_unlock(&swhash->hlist_mutex);
6692 static void swevent_hlist_put(struct perf_event *event)
6696 for_each_possible_cpu(cpu)
6697 swevent_hlist_put_cpu(event, cpu);
6700 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6702 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6705 mutex_lock(&swhash->hlist_mutex);
6707 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6708 struct swevent_hlist *hlist;
6710 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6715 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6717 swhash->hlist_refcount++;
6719 mutex_unlock(&swhash->hlist_mutex);
6724 static int swevent_hlist_get(struct perf_event *event)
6727 int cpu, failed_cpu;
6730 for_each_possible_cpu(cpu) {
6731 err = swevent_hlist_get_cpu(event, cpu);
6741 for_each_possible_cpu(cpu) {
6742 if (cpu == failed_cpu)
6744 swevent_hlist_put_cpu(event, cpu);
6751 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6753 static void sw_perf_event_destroy(struct perf_event *event)
6755 u64 event_id = event->attr.config;
6757 WARN_ON(event->parent);
6759 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6760 swevent_hlist_put(event);
6763 static int perf_swevent_init(struct perf_event *event)
6765 u64 event_id = event->attr.config;
6767 if (event->attr.type != PERF_TYPE_SOFTWARE)
6771 * no branch sampling for software events
6773 if (has_branch_stack(event))
6777 case PERF_COUNT_SW_CPU_CLOCK:
6778 case PERF_COUNT_SW_TASK_CLOCK:
6785 if (event_id >= PERF_COUNT_SW_MAX)
6788 if (!event->parent) {
6791 err = swevent_hlist_get(event);
6795 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6796 event->destroy = sw_perf_event_destroy;
6802 static struct pmu perf_swevent = {
6803 .task_ctx_nr = perf_sw_context,
6805 .capabilities = PERF_PMU_CAP_NO_NMI,
6807 .event_init = perf_swevent_init,
6808 .add = perf_swevent_add,
6809 .del = perf_swevent_del,
6810 .start = perf_swevent_start,
6811 .stop = perf_swevent_stop,
6812 .read = perf_swevent_read,
6815 #ifdef CONFIG_EVENT_TRACING
6817 static int perf_tp_filter_match(struct perf_event *event,
6818 struct perf_sample_data *data)
6820 void *record = data->raw->data;
6822 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6827 static int perf_tp_event_match(struct perf_event *event,
6828 struct perf_sample_data *data,
6829 struct pt_regs *regs)
6831 if (event->hw.state & PERF_HES_STOPPED)
6834 * All tracepoints are from kernel-space.
6836 if (event->attr.exclude_kernel)
6839 if (!perf_tp_filter_match(event, data))
6845 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6846 struct pt_regs *regs, struct hlist_head *head, int rctx,
6847 struct task_struct *task)
6849 struct perf_sample_data data;
6850 struct perf_event *event;
6852 struct perf_raw_record raw = {
6857 perf_sample_data_init(&data, addr, 0);
6860 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6861 if (perf_tp_event_match(event, &data, regs))
6862 perf_swevent_event(event, count, &data, regs);
6866 * If we got specified a target task, also iterate its context and
6867 * deliver this event there too.
6869 if (task && task != current) {
6870 struct perf_event_context *ctx;
6871 struct trace_entry *entry = record;
6874 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6878 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6879 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6881 if (event->attr.config != entry->type)
6883 if (perf_tp_event_match(event, &data, regs))
6884 perf_swevent_event(event, count, &data, regs);
6890 perf_swevent_put_recursion_context(rctx);
6892 EXPORT_SYMBOL_GPL(perf_tp_event);
6894 static void tp_perf_event_destroy(struct perf_event *event)
6896 perf_trace_destroy(event);
6899 static int perf_tp_event_init(struct perf_event *event)
6903 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6907 * no branch sampling for tracepoint events
6909 if (has_branch_stack(event))
6912 err = perf_trace_init(event);
6916 event->destroy = tp_perf_event_destroy;
6921 static struct pmu perf_tracepoint = {
6922 .task_ctx_nr = perf_sw_context,
6924 .event_init = perf_tp_event_init,
6925 .add = perf_trace_add,
6926 .del = perf_trace_del,
6927 .start = perf_swevent_start,
6928 .stop = perf_swevent_stop,
6929 .read = perf_swevent_read,
6932 static inline void perf_tp_register(void)
6934 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
6937 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
6942 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6945 filter_str = strndup_user(arg, PAGE_SIZE);
6946 if (IS_ERR(filter_str))
6947 return PTR_ERR(filter_str);
6949 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
6955 static void perf_event_free_filter(struct perf_event *event)
6957 ftrace_profile_free_filter(event);
6960 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
6962 struct bpf_prog *prog;
6964 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6967 if (event->tp_event->prog)
6970 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
6971 /* bpf programs can only be attached to u/kprobes */
6974 prog = bpf_prog_get(prog_fd);
6976 return PTR_ERR(prog);
6978 if (prog->type != BPF_PROG_TYPE_KPROBE) {
6979 /* valid fd, but invalid bpf program type */
6984 event->tp_event->prog = prog;
6989 static void perf_event_free_bpf_prog(struct perf_event *event)
6991 struct bpf_prog *prog;
6993 if (!event->tp_event)
6996 prog = event->tp_event->prog;
6998 event->tp_event->prog = NULL;
7005 static inline void perf_tp_register(void)
7009 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7014 static void perf_event_free_filter(struct perf_event *event)
7018 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7023 static void perf_event_free_bpf_prog(struct perf_event *event)
7026 #endif /* CONFIG_EVENT_TRACING */
7028 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7029 void perf_bp_event(struct perf_event *bp, void *data)
7031 struct perf_sample_data sample;
7032 struct pt_regs *regs = data;
7034 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7036 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7037 perf_swevent_event(bp, 1, &sample, regs);
7042 * hrtimer based swevent callback
7045 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7047 enum hrtimer_restart ret = HRTIMER_RESTART;
7048 struct perf_sample_data data;
7049 struct pt_regs *regs;
7050 struct perf_event *event;
7053 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7055 if (event->state != PERF_EVENT_STATE_ACTIVE)
7056 return HRTIMER_NORESTART;
7058 event->pmu->read(event);
7060 perf_sample_data_init(&data, 0, event->hw.last_period);
7061 regs = get_irq_regs();
7063 if (regs && !perf_exclude_event(event, regs)) {
7064 if (!(event->attr.exclude_idle && is_idle_task(current)))
7065 if (__perf_event_overflow(event, 1, &data, regs))
7066 ret = HRTIMER_NORESTART;
7069 period = max_t(u64, 10000, event->hw.sample_period);
7070 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7075 static void perf_swevent_start_hrtimer(struct perf_event *event)
7077 struct hw_perf_event *hwc = &event->hw;
7080 if (!is_sampling_event(event))
7083 period = local64_read(&hwc->period_left);
7088 local64_set(&hwc->period_left, 0);
7090 period = max_t(u64, 10000, hwc->sample_period);
7092 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7093 HRTIMER_MODE_REL_PINNED);
7096 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7098 struct hw_perf_event *hwc = &event->hw;
7100 if (is_sampling_event(event)) {
7101 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7102 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7104 hrtimer_cancel(&hwc->hrtimer);
7108 static void perf_swevent_init_hrtimer(struct perf_event *event)
7110 struct hw_perf_event *hwc = &event->hw;
7112 if (!is_sampling_event(event))
7115 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7116 hwc->hrtimer.function = perf_swevent_hrtimer;
7119 * Since hrtimers have a fixed rate, we can do a static freq->period
7120 * mapping and avoid the whole period adjust feedback stuff.
7122 if (event->attr.freq) {
7123 long freq = event->attr.sample_freq;
7125 event->attr.sample_period = NSEC_PER_SEC / freq;
7126 hwc->sample_period = event->attr.sample_period;
7127 local64_set(&hwc->period_left, hwc->sample_period);
7128 hwc->last_period = hwc->sample_period;
7129 event->attr.freq = 0;
7134 * Software event: cpu wall time clock
7137 static void cpu_clock_event_update(struct perf_event *event)
7142 now = local_clock();
7143 prev = local64_xchg(&event->hw.prev_count, now);
7144 local64_add(now - prev, &event->count);
7147 static void cpu_clock_event_start(struct perf_event *event, int flags)
7149 local64_set(&event->hw.prev_count, local_clock());
7150 perf_swevent_start_hrtimer(event);
7153 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7155 perf_swevent_cancel_hrtimer(event);
7156 cpu_clock_event_update(event);
7159 static int cpu_clock_event_add(struct perf_event *event, int flags)
7161 if (flags & PERF_EF_START)
7162 cpu_clock_event_start(event, flags);
7163 perf_event_update_userpage(event);
7168 static void cpu_clock_event_del(struct perf_event *event, int flags)
7170 cpu_clock_event_stop(event, flags);
7173 static void cpu_clock_event_read(struct perf_event *event)
7175 cpu_clock_event_update(event);
7178 static int cpu_clock_event_init(struct perf_event *event)
7180 if (event->attr.type != PERF_TYPE_SOFTWARE)
7183 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7187 * no branch sampling for software events
7189 if (has_branch_stack(event))
7192 perf_swevent_init_hrtimer(event);
7197 static struct pmu perf_cpu_clock = {
7198 .task_ctx_nr = perf_sw_context,
7200 .capabilities = PERF_PMU_CAP_NO_NMI,
7202 .event_init = cpu_clock_event_init,
7203 .add = cpu_clock_event_add,
7204 .del = cpu_clock_event_del,
7205 .start = cpu_clock_event_start,
7206 .stop = cpu_clock_event_stop,
7207 .read = cpu_clock_event_read,
7211 * Software event: task time clock
7214 static void task_clock_event_update(struct perf_event *event, u64 now)
7219 prev = local64_xchg(&event->hw.prev_count, now);
7221 local64_add(delta, &event->count);
7224 static void task_clock_event_start(struct perf_event *event, int flags)
7226 local64_set(&event->hw.prev_count, event->ctx->time);
7227 perf_swevent_start_hrtimer(event);
7230 static void task_clock_event_stop(struct perf_event *event, int flags)
7232 perf_swevent_cancel_hrtimer(event);
7233 task_clock_event_update(event, event->ctx->time);
7236 static int task_clock_event_add(struct perf_event *event, int flags)
7238 if (flags & PERF_EF_START)
7239 task_clock_event_start(event, flags);
7240 perf_event_update_userpage(event);
7245 static void task_clock_event_del(struct perf_event *event, int flags)
7247 task_clock_event_stop(event, PERF_EF_UPDATE);
7250 static void task_clock_event_read(struct perf_event *event)
7252 u64 now = perf_clock();
7253 u64 delta = now - event->ctx->timestamp;
7254 u64 time = event->ctx->time + delta;
7256 task_clock_event_update(event, time);
7259 static int task_clock_event_init(struct perf_event *event)
7261 if (event->attr.type != PERF_TYPE_SOFTWARE)
7264 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7268 * no branch sampling for software events
7270 if (has_branch_stack(event))
7273 perf_swevent_init_hrtimer(event);
7278 static struct pmu perf_task_clock = {
7279 .task_ctx_nr = perf_sw_context,
7281 .capabilities = PERF_PMU_CAP_NO_NMI,
7283 .event_init = task_clock_event_init,
7284 .add = task_clock_event_add,
7285 .del = task_clock_event_del,
7286 .start = task_clock_event_start,
7287 .stop = task_clock_event_stop,
7288 .read = task_clock_event_read,
7291 static void perf_pmu_nop_void(struct pmu *pmu)
7295 static int perf_pmu_nop_int(struct pmu *pmu)
7300 static void perf_pmu_start_txn(struct pmu *pmu)
7302 perf_pmu_disable(pmu);
7305 static int perf_pmu_commit_txn(struct pmu *pmu)
7307 perf_pmu_enable(pmu);
7311 static void perf_pmu_cancel_txn(struct pmu *pmu)
7313 perf_pmu_enable(pmu);
7316 static int perf_event_idx_default(struct perf_event *event)
7322 * Ensures all contexts with the same task_ctx_nr have the same
7323 * pmu_cpu_context too.
7325 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7332 list_for_each_entry(pmu, &pmus, entry) {
7333 if (pmu->task_ctx_nr == ctxn)
7334 return pmu->pmu_cpu_context;
7340 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7344 for_each_possible_cpu(cpu) {
7345 struct perf_cpu_context *cpuctx;
7347 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7349 if (cpuctx->unique_pmu == old_pmu)
7350 cpuctx->unique_pmu = pmu;
7354 static void free_pmu_context(struct pmu *pmu)
7358 mutex_lock(&pmus_lock);
7360 * Like a real lame refcount.
7362 list_for_each_entry(i, &pmus, entry) {
7363 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7364 update_pmu_context(i, pmu);
7369 free_percpu(pmu->pmu_cpu_context);
7371 mutex_unlock(&pmus_lock);
7373 static struct idr pmu_idr;
7376 type_show(struct device *dev, struct device_attribute *attr, char *page)
7378 struct pmu *pmu = dev_get_drvdata(dev);
7380 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7382 static DEVICE_ATTR_RO(type);
7385 perf_event_mux_interval_ms_show(struct device *dev,
7386 struct device_attribute *attr,
7389 struct pmu *pmu = dev_get_drvdata(dev);
7391 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7394 static DEFINE_MUTEX(mux_interval_mutex);
7397 perf_event_mux_interval_ms_store(struct device *dev,
7398 struct device_attribute *attr,
7399 const char *buf, size_t count)
7401 struct pmu *pmu = dev_get_drvdata(dev);
7402 int timer, cpu, ret;
7404 ret = kstrtoint(buf, 0, &timer);
7411 /* same value, noting to do */
7412 if (timer == pmu->hrtimer_interval_ms)
7415 mutex_lock(&mux_interval_mutex);
7416 pmu->hrtimer_interval_ms = timer;
7418 /* update all cpuctx for this PMU */
7420 for_each_online_cpu(cpu) {
7421 struct perf_cpu_context *cpuctx;
7422 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7423 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7425 cpu_function_call(cpu,
7426 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7429 mutex_unlock(&mux_interval_mutex);
7433 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7435 static struct attribute *pmu_dev_attrs[] = {
7436 &dev_attr_type.attr,
7437 &dev_attr_perf_event_mux_interval_ms.attr,
7440 ATTRIBUTE_GROUPS(pmu_dev);
7442 static int pmu_bus_running;
7443 static struct bus_type pmu_bus = {
7444 .name = "event_source",
7445 .dev_groups = pmu_dev_groups,
7448 static void pmu_dev_release(struct device *dev)
7453 static int pmu_dev_alloc(struct pmu *pmu)
7457 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7461 pmu->dev->groups = pmu->attr_groups;
7462 device_initialize(pmu->dev);
7463 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7467 dev_set_drvdata(pmu->dev, pmu);
7468 pmu->dev->bus = &pmu_bus;
7469 pmu->dev->release = pmu_dev_release;
7470 ret = device_add(pmu->dev);
7478 put_device(pmu->dev);
7482 static struct lock_class_key cpuctx_mutex;
7483 static struct lock_class_key cpuctx_lock;
7485 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7489 mutex_lock(&pmus_lock);
7491 pmu->pmu_disable_count = alloc_percpu(int);
7492 if (!pmu->pmu_disable_count)
7501 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7509 if (pmu_bus_running) {
7510 ret = pmu_dev_alloc(pmu);
7516 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7517 if (pmu->pmu_cpu_context)
7518 goto got_cpu_context;
7521 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7522 if (!pmu->pmu_cpu_context)
7525 for_each_possible_cpu(cpu) {
7526 struct perf_cpu_context *cpuctx;
7528 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7529 __perf_event_init_context(&cpuctx->ctx);
7530 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7531 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7532 cpuctx->ctx.pmu = pmu;
7534 __perf_mux_hrtimer_init(cpuctx, cpu);
7536 cpuctx->unique_pmu = pmu;
7540 if (!pmu->start_txn) {
7541 if (pmu->pmu_enable) {
7543 * If we have pmu_enable/pmu_disable calls, install
7544 * transaction stubs that use that to try and batch
7545 * hardware accesses.
7547 pmu->start_txn = perf_pmu_start_txn;
7548 pmu->commit_txn = perf_pmu_commit_txn;
7549 pmu->cancel_txn = perf_pmu_cancel_txn;
7551 pmu->start_txn = perf_pmu_nop_void;
7552 pmu->commit_txn = perf_pmu_nop_int;
7553 pmu->cancel_txn = perf_pmu_nop_void;
7557 if (!pmu->pmu_enable) {
7558 pmu->pmu_enable = perf_pmu_nop_void;
7559 pmu->pmu_disable = perf_pmu_nop_void;
7562 if (!pmu->event_idx)
7563 pmu->event_idx = perf_event_idx_default;
7565 list_add_rcu(&pmu->entry, &pmus);
7566 atomic_set(&pmu->exclusive_cnt, 0);
7569 mutex_unlock(&pmus_lock);
7574 device_del(pmu->dev);
7575 put_device(pmu->dev);
7578 if (pmu->type >= PERF_TYPE_MAX)
7579 idr_remove(&pmu_idr, pmu->type);
7582 free_percpu(pmu->pmu_disable_count);
7585 EXPORT_SYMBOL_GPL(perf_pmu_register);
7587 void perf_pmu_unregister(struct pmu *pmu)
7589 mutex_lock(&pmus_lock);
7590 list_del_rcu(&pmu->entry);
7591 mutex_unlock(&pmus_lock);
7594 * We dereference the pmu list under both SRCU and regular RCU, so
7595 * synchronize against both of those.
7597 synchronize_srcu(&pmus_srcu);
7600 free_percpu(pmu->pmu_disable_count);
7601 if (pmu->type >= PERF_TYPE_MAX)
7602 idr_remove(&pmu_idr, pmu->type);
7603 device_del(pmu->dev);
7604 put_device(pmu->dev);
7605 free_pmu_context(pmu);
7607 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7609 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7611 struct perf_event_context *ctx = NULL;
7614 if (!try_module_get(pmu->module))
7617 if (event->group_leader != event) {
7619 * This ctx->mutex can nest when we're called through
7620 * inheritance. See the perf_event_ctx_lock_nested() comment.
7622 ctx = perf_event_ctx_lock_nested(event->group_leader,
7623 SINGLE_DEPTH_NESTING);
7628 ret = pmu->event_init(event);
7631 perf_event_ctx_unlock(event->group_leader, ctx);
7634 module_put(pmu->module);
7639 struct pmu *perf_init_event(struct perf_event *event)
7641 struct pmu *pmu = NULL;
7645 idx = srcu_read_lock(&pmus_srcu);
7648 pmu = idr_find(&pmu_idr, event->attr.type);
7651 ret = perf_try_init_event(pmu, event);
7657 list_for_each_entry_rcu(pmu, &pmus, entry) {
7658 ret = perf_try_init_event(pmu, event);
7662 if (ret != -ENOENT) {
7667 pmu = ERR_PTR(-ENOENT);
7669 srcu_read_unlock(&pmus_srcu, idx);
7674 static void account_event_cpu(struct perf_event *event, int cpu)
7679 if (is_cgroup_event(event))
7680 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7683 static void account_event(struct perf_event *event)
7688 if (event->attach_state & PERF_ATTACH_TASK)
7689 static_key_slow_inc(&perf_sched_events.key);
7690 if (event->attr.mmap || event->attr.mmap_data)
7691 atomic_inc(&nr_mmap_events);
7692 if (event->attr.comm)
7693 atomic_inc(&nr_comm_events);
7694 if (event->attr.task)
7695 atomic_inc(&nr_task_events);
7696 if (event->attr.freq) {
7697 if (atomic_inc_return(&nr_freq_events) == 1)
7698 tick_nohz_full_kick_all();
7700 if (event->attr.context_switch) {
7701 atomic_inc(&nr_switch_events);
7702 static_key_slow_inc(&perf_sched_events.key);
7704 if (has_branch_stack(event))
7705 static_key_slow_inc(&perf_sched_events.key);
7706 if (is_cgroup_event(event))
7707 static_key_slow_inc(&perf_sched_events.key);
7709 account_event_cpu(event, event->cpu);
7713 * Allocate and initialize a event structure
7715 static struct perf_event *
7716 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7717 struct task_struct *task,
7718 struct perf_event *group_leader,
7719 struct perf_event *parent_event,
7720 perf_overflow_handler_t overflow_handler,
7721 void *context, int cgroup_fd)
7724 struct perf_event *event;
7725 struct hw_perf_event *hwc;
7728 if ((unsigned)cpu >= nr_cpu_ids) {
7729 if (!task || cpu != -1)
7730 return ERR_PTR(-EINVAL);
7733 event = kzalloc(sizeof(*event), GFP_KERNEL);
7735 return ERR_PTR(-ENOMEM);
7738 * Single events are their own group leaders, with an
7739 * empty sibling list:
7742 group_leader = event;
7744 mutex_init(&event->child_mutex);
7745 INIT_LIST_HEAD(&event->child_list);
7747 INIT_LIST_HEAD(&event->group_entry);
7748 INIT_LIST_HEAD(&event->event_entry);
7749 INIT_LIST_HEAD(&event->sibling_list);
7750 INIT_LIST_HEAD(&event->rb_entry);
7751 INIT_LIST_HEAD(&event->active_entry);
7752 INIT_HLIST_NODE(&event->hlist_entry);
7755 init_waitqueue_head(&event->waitq);
7756 init_irq_work(&event->pending, perf_pending_event);
7758 mutex_init(&event->mmap_mutex);
7760 atomic_long_set(&event->refcount, 1);
7762 event->attr = *attr;
7763 event->group_leader = group_leader;
7767 event->parent = parent_event;
7769 event->ns = get_pid_ns(task_active_pid_ns(current));
7770 event->id = atomic64_inc_return(&perf_event_id);
7772 event->state = PERF_EVENT_STATE_INACTIVE;
7775 event->attach_state = PERF_ATTACH_TASK;
7777 * XXX pmu::event_init needs to know what task to account to
7778 * and we cannot use the ctx information because we need the
7779 * pmu before we get a ctx.
7781 event->hw.target = task;
7784 event->clock = &local_clock;
7786 event->clock = parent_event->clock;
7788 if (!overflow_handler && parent_event) {
7789 overflow_handler = parent_event->overflow_handler;
7790 context = parent_event->overflow_handler_context;
7793 event->overflow_handler = overflow_handler;
7794 event->overflow_handler_context = context;
7796 perf_event__state_init(event);
7801 hwc->sample_period = attr->sample_period;
7802 if (attr->freq && attr->sample_freq)
7803 hwc->sample_period = 1;
7804 hwc->last_period = hwc->sample_period;
7806 local64_set(&hwc->period_left, hwc->sample_period);
7809 * we currently do not support PERF_FORMAT_GROUP on inherited events
7811 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7814 if (!has_branch_stack(event))
7815 event->attr.branch_sample_type = 0;
7817 if (cgroup_fd != -1) {
7818 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7823 pmu = perf_init_event(event);
7826 else if (IS_ERR(pmu)) {
7831 err = exclusive_event_init(event);
7835 if (!event->parent) {
7836 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7837 err = get_callchain_buffers();
7846 exclusive_event_destroy(event);
7850 event->destroy(event);
7851 module_put(pmu->module);
7853 if (is_cgroup_event(event))
7854 perf_detach_cgroup(event);
7856 put_pid_ns(event->ns);
7859 return ERR_PTR(err);
7862 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7863 struct perf_event_attr *attr)
7868 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
7872 * zero the full structure, so that a short copy will be nice.
7874 memset(attr, 0, sizeof(*attr));
7876 ret = get_user(size, &uattr->size);
7880 if (size > PAGE_SIZE) /* silly large */
7883 if (!size) /* abi compat */
7884 size = PERF_ATTR_SIZE_VER0;
7886 if (size < PERF_ATTR_SIZE_VER0)
7890 * If we're handed a bigger struct than we know of,
7891 * ensure all the unknown bits are 0 - i.e. new
7892 * user-space does not rely on any kernel feature
7893 * extensions we dont know about yet.
7895 if (size > sizeof(*attr)) {
7896 unsigned char __user *addr;
7897 unsigned char __user *end;
7900 addr = (void __user *)uattr + sizeof(*attr);
7901 end = (void __user *)uattr + size;
7903 for (; addr < end; addr++) {
7904 ret = get_user(val, addr);
7910 size = sizeof(*attr);
7913 ret = copy_from_user(attr, uattr, size);
7917 if (attr->__reserved_1)
7920 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
7923 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
7926 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
7927 u64 mask = attr->branch_sample_type;
7929 /* only using defined bits */
7930 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
7933 /* at least one branch bit must be set */
7934 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
7937 /* propagate priv level, when not set for branch */
7938 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
7940 /* exclude_kernel checked on syscall entry */
7941 if (!attr->exclude_kernel)
7942 mask |= PERF_SAMPLE_BRANCH_KERNEL;
7944 if (!attr->exclude_user)
7945 mask |= PERF_SAMPLE_BRANCH_USER;
7947 if (!attr->exclude_hv)
7948 mask |= PERF_SAMPLE_BRANCH_HV;
7950 * adjust user setting (for HW filter setup)
7952 attr->branch_sample_type = mask;
7954 /* privileged levels capture (kernel, hv): check permissions */
7955 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
7956 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
7960 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
7961 ret = perf_reg_validate(attr->sample_regs_user);
7966 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
7967 if (!arch_perf_have_user_stack_dump())
7971 * We have __u32 type for the size, but so far
7972 * we can only use __u16 as maximum due to the
7973 * __u16 sample size limit.
7975 if (attr->sample_stack_user >= USHRT_MAX)
7977 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
7981 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
7982 ret = perf_reg_validate(attr->sample_regs_intr);
7987 put_user(sizeof(*attr), &uattr->size);
7993 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
7995 struct ring_buffer *rb = NULL;
8001 /* don't allow circular references */
8002 if (event == output_event)
8006 * Don't allow cross-cpu buffers
8008 if (output_event->cpu != event->cpu)
8012 * If its not a per-cpu rb, it must be the same task.
8014 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8018 * Mixing clocks in the same buffer is trouble you don't need.
8020 if (output_event->clock != event->clock)
8024 * If both events generate aux data, they must be on the same PMU
8026 if (has_aux(event) && has_aux(output_event) &&
8027 event->pmu != output_event->pmu)
8031 mutex_lock(&event->mmap_mutex);
8032 /* Can't redirect output if we've got an active mmap() */
8033 if (atomic_read(&event->mmap_count))
8037 /* get the rb we want to redirect to */
8038 rb = ring_buffer_get(output_event);
8043 ring_buffer_attach(event, rb);
8047 mutex_unlock(&event->mmap_mutex);
8053 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8059 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8062 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8064 bool nmi_safe = false;
8067 case CLOCK_MONOTONIC:
8068 event->clock = &ktime_get_mono_fast_ns;
8072 case CLOCK_MONOTONIC_RAW:
8073 event->clock = &ktime_get_raw_fast_ns;
8077 case CLOCK_REALTIME:
8078 event->clock = &ktime_get_real_ns;
8081 case CLOCK_BOOTTIME:
8082 event->clock = &ktime_get_boot_ns;
8086 event->clock = &ktime_get_tai_ns;
8093 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8100 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8102 * @attr_uptr: event_id type attributes for monitoring/sampling
8105 * @group_fd: group leader event fd
8107 SYSCALL_DEFINE5(perf_event_open,
8108 struct perf_event_attr __user *, attr_uptr,
8109 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8111 struct perf_event *group_leader = NULL, *output_event = NULL;
8112 struct perf_event *event, *sibling;
8113 struct perf_event_attr attr;
8114 struct perf_event_context *ctx, *uninitialized_var(gctx);
8115 struct file *event_file = NULL;
8116 struct fd group = {NULL, 0};
8117 struct task_struct *task = NULL;
8122 int f_flags = O_RDWR;
8125 /* for future expandability... */
8126 if (flags & ~PERF_FLAG_ALL)
8129 err = perf_copy_attr(attr_uptr, &attr);
8133 if (!attr.exclude_kernel) {
8134 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8139 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8142 if (attr.sample_period & (1ULL << 63))
8147 * In cgroup mode, the pid argument is used to pass the fd
8148 * opened to the cgroup directory in cgroupfs. The cpu argument
8149 * designates the cpu on which to monitor threads from that
8152 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8155 if (flags & PERF_FLAG_FD_CLOEXEC)
8156 f_flags |= O_CLOEXEC;
8158 event_fd = get_unused_fd_flags(f_flags);
8162 if (group_fd != -1) {
8163 err = perf_fget_light(group_fd, &group);
8166 group_leader = group.file->private_data;
8167 if (flags & PERF_FLAG_FD_OUTPUT)
8168 output_event = group_leader;
8169 if (flags & PERF_FLAG_FD_NO_GROUP)
8170 group_leader = NULL;
8173 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8174 task = find_lively_task_by_vpid(pid);
8176 err = PTR_ERR(task);
8181 if (task && group_leader &&
8182 group_leader->attr.inherit != attr.inherit) {
8189 if (flags & PERF_FLAG_PID_CGROUP)
8192 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8193 NULL, NULL, cgroup_fd);
8194 if (IS_ERR(event)) {
8195 err = PTR_ERR(event);
8199 if (is_sampling_event(event)) {
8200 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8206 account_event(event);
8209 * Special case software events and allow them to be part of
8210 * any hardware group.
8214 if (attr.use_clockid) {
8215 err = perf_event_set_clock(event, attr.clockid);
8221 (is_software_event(event) != is_software_event(group_leader))) {
8222 if (is_software_event(event)) {
8224 * If event and group_leader are not both a software
8225 * event, and event is, then group leader is not.
8227 * Allow the addition of software events to !software
8228 * groups, this is safe because software events never
8231 pmu = group_leader->pmu;
8232 } else if (is_software_event(group_leader) &&
8233 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8235 * In case the group is a pure software group, and we
8236 * try to add a hardware event, move the whole group to
8237 * the hardware context.
8244 * Get the target context (task or percpu):
8246 ctx = find_get_context(pmu, task, event);
8252 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8258 put_task_struct(task);
8263 * Look up the group leader (we will attach this event to it):
8269 * Do not allow a recursive hierarchy (this new sibling
8270 * becoming part of another group-sibling):
8272 if (group_leader->group_leader != group_leader)
8275 /* All events in a group should have the same clock */
8276 if (group_leader->clock != event->clock)
8280 * Do not allow to attach to a group in a different
8281 * task or CPU context:
8285 * Make sure we're both on the same task, or both
8288 if (group_leader->ctx->task != ctx->task)
8292 * Make sure we're both events for the same CPU;
8293 * grouping events for different CPUs is broken; since
8294 * you can never concurrently schedule them anyhow.
8296 if (group_leader->cpu != event->cpu)
8299 if (group_leader->ctx != ctx)
8304 * Only a group leader can be exclusive or pinned
8306 if (attr.exclusive || attr.pinned)
8311 err = perf_event_set_output(event, output_event);
8316 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8318 if (IS_ERR(event_file)) {
8319 err = PTR_ERR(event_file);
8324 gctx = group_leader->ctx;
8325 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8327 mutex_lock(&ctx->mutex);
8330 if (!perf_event_validate_size(event)) {
8336 * Must be under the same ctx::mutex as perf_install_in_context(),
8337 * because we need to serialize with concurrent event creation.
8339 if (!exclusive_event_installable(event, ctx)) {
8340 /* exclusive and group stuff are assumed mutually exclusive */
8341 WARN_ON_ONCE(move_group);
8347 WARN_ON_ONCE(ctx->parent_ctx);
8351 * See perf_event_ctx_lock() for comments on the details
8352 * of swizzling perf_event::ctx.
8354 perf_remove_from_context(group_leader, false);
8356 list_for_each_entry(sibling, &group_leader->sibling_list,
8358 perf_remove_from_context(sibling, false);
8363 * Wait for everybody to stop referencing the events through
8364 * the old lists, before installing it on new lists.
8369 * Install the group siblings before the group leader.
8371 * Because a group leader will try and install the entire group
8372 * (through the sibling list, which is still in-tact), we can
8373 * end up with siblings installed in the wrong context.
8375 * By installing siblings first we NO-OP because they're not
8376 * reachable through the group lists.
8378 list_for_each_entry(sibling, &group_leader->sibling_list,
8380 perf_event__state_init(sibling);
8381 perf_install_in_context(ctx, sibling, sibling->cpu);
8386 * Removing from the context ends up with disabled
8387 * event. What we want here is event in the initial
8388 * startup state, ready to be add into new context.
8390 perf_event__state_init(group_leader);
8391 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8395 * Now that all events are installed in @ctx, nothing
8396 * references @gctx anymore, so drop the last reference we have
8403 * Precalculate sample_data sizes; do while holding ctx::mutex such
8404 * that we're serialized against further additions and before
8405 * perf_install_in_context() which is the point the event is active and
8406 * can use these values.
8408 perf_event__header_size(event);
8409 perf_event__id_header_size(event);
8411 perf_install_in_context(ctx, event, event->cpu);
8412 perf_unpin_context(ctx);
8415 mutex_unlock(&gctx->mutex);
8416 mutex_unlock(&ctx->mutex);
8420 event->owner = current;
8422 mutex_lock(¤t->perf_event_mutex);
8423 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8424 mutex_unlock(¤t->perf_event_mutex);
8427 * Drop the reference on the group_event after placing the
8428 * new event on the sibling_list. This ensures destruction
8429 * of the group leader will find the pointer to itself in
8430 * perf_group_detach().
8433 fd_install(event_fd, event_file);
8438 mutex_unlock(&gctx->mutex);
8439 mutex_unlock(&ctx->mutex);
8443 perf_unpin_context(ctx);
8451 put_task_struct(task);
8455 put_unused_fd(event_fd);
8460 * perf_event_create_kernel_counter
8462 * @attr: attributes of the counter to create
8463 * @cpu: cpu in which the counter is bound
8464 * @task: task to profile (NULL for percpu)
8467 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8468 struct task_struct *task,
8469 perf_overflow_handler_t overflow_handler,
8472 struct perf_event_context *ctx;
8473 struct perf_event *event;
8477 * Get the target context (task or percpu):
8480 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8481 overflow_handler, context, -1);
8482 if (IS_ERR(event)) {
8483 err = PTR_ERR(event);
8487 /* Mark owner so we could distinguish it from user events. */
8488 event->owner = EVENT_OWNER_KERNEL;
8490 account_event(event);
8492 ctx = find_get_context(event->pmu, task, event);
8498 WARN_ON_ONCE(ctx->parent_ctx);
8499 mutex_lock(&ctx->mutex);
8500 if (!exclusive_event_installable(event, ctx)) {
8501 mutex_unlock(&ctx->mutex);
8502 perf_unpin_context(ctx);
8508 perf_install_in_context(ctx, event, cpu);
8509 perf_unpin_context(ctx);
8510 mutex_unlock(&ctx->mutex);
8517 return ERR_PTR(err);
8519 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8521 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8523 struct perf_event_context *src_ctx;
8524 struct perf_event_context *dst_ctx;
8525 struct perf_event *event, *tmp;
8528 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8529 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8532 * See perf_event_ctx_lock() for comments on the details
8533 * of swizzling perf_event::ctx.
8535 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8536 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8538 perf_remove_from_context(event, false);
8539 unaccount_event_cpu(event, src_cpu);
8541 list_add(&event->migrate_entry, &events);
8545 * Wait for the events to quiesce before re-instating them.
8550 * Re-instate events in 2 passes.
8552 * Skip over group leaders and only install siblings on this first
8553 * pass, siblings will not get enabled without a leader, however a
8554 * leader will enable its siblings, even if those are still on the old
8557 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8558 if (event->group_leader == event)
8561 list_del(&event->migrate_entry);
8562 if (event->state >= PERF_EVENT_STATE_OFF)
8563 event->state = PERF_EVENT_STATE_INACTIVE;
8564 account_event_cpu(event, dst_cpu);
8565 perf_install_in_context(dst_ctx, event, dst_cpu);
8570 * Once all the siblings are setup properly, install the group leaders
8573 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8574 list_del(&event->migrate_entry);
8575 if (event->state >= PERF_EVENT_STATE_OFF)
8576 event->state = PERF_EVENT_STATE_INACTIVE;
8577 account_event_cpu(event, dst_cpu);
8578 perf_install_in_context(dst_ctx, event, dst_cpu);
8581 mutex_unlock(&dst_ctx->mutex);
8582 mutex_unlock(&src_ctx->mutex);
8584 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8586 static void sync_child_event(struct perf_event *child_event,
8587 struct task_struct *child)
8589 struct perf_event *parent_event = child_event->parent;
8592 if (child_event->attr.inherit_stat)
8593 perf_event_read_event(child_event, child);
8595 child_val = perf_event_count(child_event);
8598 * Add back the child's count to the parent's count:
8600 atomic64_add(child_val, &parent_event->child_count);
8601 atomic64_add(child_event->total_time_enabled,
8602 &parent_event->child_total_time_enabled);
8603 atomic64_add(child_event->total_time_running,
8604 &parent_event->child_total_time_running);
8607 * Remove this event from the parent's list
8609 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8610 mutex_lock(&parent_event->child_mutex);
8611 list_del_init(&child_event->child_list);
8612 mutex_unlock(&parent_event->child_mutex);
8615 * Make sure user/parent get notified, that we just
8618 perf_event_wakeup(parent_event);
8621 * Release the parent event, if this was the last
8624 put_event(parent_event);
8628 __perf_event_exit_task(struct perf_event *child_event,
8629 struct perf_event_context *child_ctx,
8630 struct task_struct *child)
8633 * Do not destroy the 'original' grouping; because of the context
8634 * switch optimization the original events could've ended up in a
8635 * random child task.
8637 * If we were to destroy the original group, all group related
8638 * operations would cease to function properly after this random
8641 * Do destroy all inherited groups, we don't care about those
8642 * and being thorough is better.
8644 perf_remove_from_context(child_event, !!child_event->parent);
8647 * It can happen that the parent exits first, and has events
8648 * that are still around due to the child reference. These
8649 * events need to be zapped.
8651 if (child_event->parent) {
8652 sync_child_event(child_event, child);
8653 free_event(child_event);
8655 child_event->state = PERF_EVENT_STATE_EXIT;
8656 perf_event_wakeup(child_event);
8660 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8662 struct perf_event *child_event, *next;
8663 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8664 unsigned long flags;
8666 if (likely(!child->perf_event_ctxp[ctxn])) {
8667 perf_event_task(child, NULL, 0);
8671 local_irq_save(flags);
8673 * We can't reschedule here because interrupts are disabled,
8674 * and either child is current or it is a task that can't be
8675 * scheduled, so we are now safe from rescheduling changing
8678 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8681 * Take the context lock here so that if find_get_context is
8682 * reading child->perf_event_ctxp, we wait until it has
8683 * incremented the context's refcount before we do put_ctx below.
8685 raw_spin_lock(&child_ctx->lock);
8686 task_ctx_sched_out(child_ctx);
8687 child->perf_event_ctxp[ctxn] = NULL;
8690 * If this context is a clone; unclone it so it can't get
8691 * swapped to another process while we're removing all
8692 * the events from it.
8694 clone_ctx = unclone_ctx(child_ctx);
8695 update_context_time(child_ctx);
8696 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8702 * Report the task dead after unscheduling the events so that we
8703 * won't get any samples after PERF_RECORD_EXIT. We can however still
8704 * get a few PERF_RECORD_READ events.
8706 perf_event_task(child, child_ctx, 0);
8709 * We can recurse on the same lock type through:
8711 * __perf_event_exit_task()
8712 * sync_child_event()
8714 * mutex_lock(&ctx->mutex)
8716 * But since its the parent context it won't be the same instance.
8718 mutex_lock(&child_ctx->mutex);
8720 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8721 __perf_event_exit_task(child_event, child_ctx, child);
8723 mutex_unlock(&child_ctx->mutex);
8729 * When a child task exits, feed back event values to parent events.
8731 void perf_event_exit_task(struct task_struct *child)
8733 struct perf_event *event, *tmp;
8736 mutex_lock(&child->perf_event_mutex);
8737 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8739 list_del_init(&event->owner_entry);
8742 * Ensure the list deletion is visible before we clear
8743 * the owner, closes a race against perf_release() where
8744 * we need to serialize on the owner->perf_event_mutex.
8747 event->owner = NULL;
8749 mutex_unlock(&child->perf_event_mutex);
8751 for_each_task_context_nr(ctxn)
8752 perf_event_exit_task_context(child, ctxn);
8755 static void perf_free_event(struct perf_event *event,
8756 struct perf_event_context *ctx)
8758 struct perf_event *parent = event->parent;
8760 if (WARN_ON_ONCE(!parent))
8763 mutex_lock(&parent->child_mutex);
8764 list_del_init(&event->child_list);
8765 mutex_unlock(&parent->child_mutex);
8769 raw_spin_lock_irq(&ctx->lock);
8770 perf_group_detach(event);
8771 list_del_event(event, ctx);
8772 raw_spin_unlock_irq(&ctx->lock);
8777 * Free an unexposed, unused context as created by inheritance by
8778 * perf_event_init_task below, used by fork() in case of fail.
8780 * Not all locks are strictly required, but take them anyway to be nice and
8781 * help out with the lockdep assertions.
8783 void perf_event_free_task(struct task_struct *task)
8785 struct perf_event_context *ctx;
8786 struct perf_event *event, *tmp;
8789 for_each_task_context_nr(ctxn) {
8790 ctx = task->perf_event_ctxp[ctxn];
8794 mutex_lock(&ctx->mutex);
8796 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8798 perf_free_event(event, ctx);
8800 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8802 perf_free_event(event, ctx);
8804 if (!list_empty(&ctx->pinned_groups) ||
8805 !list_empty(&ctx->flexible_groups))
8808 mutex_unlock(&ctx->mutex);
8814 void perf_event_delayed_put(struct task_struct *task)
8818 for_each_task_context_nr(ctxn)
8819 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8822 struct perf_event *perf_event_get(unsigned int fd)
8826 struct perf_event *event;
8828 err = perf_fget_light(fd, &f);
8830 return ERR_PTR(err);
8832 event = f.file->private_data;
8833 atomic_long_inc(&event->refcount);
8839 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
8842 return ERR_PTR(-EINVAL);
8844 return &event->attr;
8848 * inherit a event from parent task to child task:
8850 static struct perf_event *
8851 inherit_event(struct perf_event *parent_event,
8852 struct task_struct *parent,
8853 struct perf_event_context *parent_ctx,
8854 struct task_struct *child,
8855 struct perf_event *group_leader,
8856 struct perf_event_context *child_ctx)
8858 enum perf_event_active_state parent_state = parent_event->state;
8859 struct perf_event *child_event;
8860 unsigned long flags;
8863 * Instead of creating recursive hierarchies of events,
8864 * we link inherited events back to the original parent,
8865 * which has a filp for sure, which we use as the reference
8868 if (parent_event->parent)
8869 parent_event = parent_event->parent;
8871 child_event = perf_event_alloc(&parent_event->attr,
8874 group_leader, parent_event,
8876 if (IS_ERR(child_event))
8879 if (is_orphaned_event(parent_event) ||
8880 !atomic_long_inc_not_zero(&parent_event->refcount)) {
8881 free_event(child_event);
8888 * Make the child state follow the state of the parent event,
8889 * not its attr.disabled bit. We hold the parent's mutex,
8890 * so we won't race with perf_event_{en, dis}able_family.
8892 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
8893 child_event->state = PERF_EVENT_STATE_INACTIVE;
8895 child_event->state = PERF_EVENT_STATE_OFF;
8897 if (parent_event->attr.freq) {
8898 u64 sample_period = parent_event->hw.sample_period;
8899 struct hw_perf_event *hwc = &child_event->hw;
8901 hwc->sample_period = sample_period;
8902 hwc->last_period = sample_period;
8904 local64_set(&hwc->period_left, sample_period);
8907 child_event->ctx = child_ctx;
8908 child_event->overflow_handler = parent_event->overflow_handler;
8909 child_event->overflow_handler_context
8910 = parent_event->overflow_handler_context;
8913 * Precalculate sample_data sizes
8915 perf_event__header_size(child_event);
8916 perf_event__id_header_size(child_event);
8919 * Link it up in the child's context:
8921 raw_spin_lock_irqsave(&child_ctx->lock, flags);
8922 add_event_to_ctx(child_event, child_ctx);
8923 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8926 * Link this into the parent event's child list
8928 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8929 mutex_lock(&parent_event->child_mutex);
8930 list_add_tail(&child_event->child_list, &parent_event->child_list);
8931 mutex_unlock(&parent_event->child_mutex);
8936 static int inherit_group(struct perf_event *parent_event,
8937 struct task_struct *parent,
8938 struct perf_event_context *parent_ctx,
8939 struct task_struct *child,
8940 struct perf_event_context *child_ctx)
8942 struct perf_event *leader;
8943 struct perf_event *sub;
8944 struct perf_event *child_ctr;
8946 leader = inherit_event(parent_event, parent, parent_ctx,
8947 child, NULL, child_ctx);
8949 return PTR_ERR(leader);
8950 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
8951 child_ctr = inherit_event(sub, parent, parent_ctx,
8952 child, leader, child_ctx);
8953 if (IS_ERR(child_ctr))
8954 return PTR_ERR(child_ctr);
8960 inherit_task_group(struct perf_event *event, struct task_struct *parent,
8961 struct perf_event_context *parent_ctx,
8962 struct task_struct *child, int ctxn,
8966 struct perf_event_context *child_ctx;
8968 if (!event->attr.inherit) {
8973 child_ctx = child->perf_event_ctxp[ctxn];
8976 * This is executed from the parent task context, so
8977 * inherit events that have been marked for cloning.
8978 * First allocate and initialize a context for the
8982 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
8986 child->perf_event_ctxp[ctxn] = child_ctx;
8989 ret = inherit_group(event, parent, parent_ctx,
8999 * Initialize the perf_event context in task_struct
9001 static int perf_event_init_context(struct task_struct *child, int ctxn)
9003 struct perf_event_context *child_ctx, *parent_ctx;
9004 struct perf_event_context *cloned_ctx;
9005 struct perf_event *event;
9006 struct task_struct *parent = current;
9007 int inherited_all = 1;
9008 unsigned long flags;
9011 if (likely(!parent->perf_event_ctxp[ctxn]))
9015 * If the parent's context is a clone, pin it so it won't get
9018 parent_ctx = perf_pin_task_context(parent, ctxn);
9023 * No need to check if parent_ctx != NULL here; since we saw
9024 * it non-NULL earlier, the only reason for it to become NULL
9025 * is if we exit, and since we're currently in the middle of
9026 * a fork we can't be exiting at the same time.
9030 * Lock the parent list. No need to lock the child - not PID
9031 * hashed yet and not running, so nobody can access it.
9033 mutex_lock(&parent_ctx->mutex);
9036 * We dont have to disable NMIs - we are only looking at
9037 * the list, not manipulating it:
9039 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9040 ret = inherit_task_group(event, parent, parent_ctx,
9041 child, ctxn, &inherited_all);
9047 * We can't hold ctx->lock when iterating the ->flexible_group list due
9048 * to allocations, but we need to prevent rotation because
9049 * rotate_ctx() will change the list from interrupt context.
9051 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9052 parent_ctx->rotate_disable = 1;
9053 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9055 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9056 ret = inherit_task_group(event, parent, parent_ctx,
9057 child, ctxn, &inherited_all);
9062 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9063 parent_ctx->rotate_disable = 0;
9065 child_ctx = child->perf_event_ctxp[ctxn];
9067 if (child_ctx && inherited_all) {
9069 * Mark the child context as a clone of the parent
9070 * context, or of whatever the parent is a clone of.
9072 * Note that if the parent is a clone, the holding of
9073 * parent_ctx->lock avoids it from being uncloned.
9075 cloned_ctx = parent_ctx->parent_ctx;
9077 child_ctx->parent_ctx = cloned_ctx;
9078 child_ctx->parent_gen = parent_ctx->parent_gen;
9080 child_ctx->parent_ctx = parent_ctx;
9081 child_ctx->parent_gen = parent_ctx->generation;
9083 get_ctx(child_ctx->parent_ctx);
9086 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9087 mutex_unlock(&parent_ctx->mutex);
9089 perf_unpin_context(parent_ctx);
9090 put_ctx(parent_ctx);
9096 * Initialize the perf_event context in task_struct
9098 int perf_event_init_task(struct task_struct *child)
9102 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9103 mutex_init(&child->perf_event_mutex);
9104 INIT_LIST_HEAD(&child->perf_event_list);
9106 for_each_task_context_nr(ctxn) {
9107 ret = perf_event_init_context(child, ctxn);
9109 perf_event_free_task(child);
9117 static void __init perf_event_init_all_cpus(void)
9119 struct swevent_htable *swhash;
9122 for_each_possible_cpu(cpu) {
9123 swhash = &per_cpu(swevent_htable, cpu);
9124 mutex_init(&swhash->hlist_mutex);
9125 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9129 static void perf_event_init_cpu(int cpu)
9131 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9133 mutex_lock(&swhash->hlist_mutex);
9134 swhash->online = true;
9135 if (swhash->hlist_refcount > 0) {
9136 struct swevent_hlist *hlist;
9138 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9140 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9142 mutex_unlock(&swhash->hlist_mutex);
9145 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9146 static void __perf_event_exit_context(void *__info)
9148 struct remove_event re = { .detach_group = true };
9149 struct perf_event_context *ctx = __info;
9152 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9153 __perf_remove_from_context(&re);
9157 static void perf_event_exit_cpu_context(int cpu)
9159 struct perf_event_context *ctx;
9163 idx = srcu_read_lock(&pmus_srcu);
9164 list_for_each_entry_rcu(pmu, &pmus, entry) {
9165 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9167 mutex_lock(&ctx->mutex);
9168 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9169 mutex_unlock(&ctx->mutex);
9171 srcu_read_unlock(&pmus_srcu, idx);
9174 static void perf_event_exit_cpu(int cpu)
9176 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9178 perf_event_exit_cpu_context(cpu);
9180 mutex_lock(&swhash->hlist_mutex);
9181 swhash->online = false;
9182 swevent_hlist_release(swhash);
9183 mutex_unlock(&swhash->hlist_mutex);
9186 static inline void perf_event_exit_cpu(int cpu) { }
9190 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9194 for_each_online_cpu(cpu)
9195 perf_event_exit_cpu(cpu);
9201 * Run the perf reboot notifier at the very last possible moment so that
9202 * the generic watchdog code runs as long as possible.
9204 static struct notifier_block perf_reboot_notifier = {
9205 .notifier_call = perf_reboot,
9206 .priority = INT_MIN,
9210 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9212 unsigned int cpu = (long)hcpu;
9214 switch (action & ~CPU_TASKS_FROZEN) {
9216 case CPU_UP_PREPARE:
9217 case CPU_DOWN_FAILED:
9218 perf_event_init_cpu(cpu);
9221 case CPU_UP_CANCELED:
9222 case CPU_DOWN_PREPARE:
9223 perf_event_exit_cpu(cpu);
9232 void __init perf_event_init(void)
9238 perf_event_init_all_cpus();
9239 init_srcu_struct(&pmus_srcu);
9240 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9241 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9242 perf_pmu_register(&perf_task_clock, NULL, -1);
9244 perf_cpu_notifier(perf_cpu_notify);
9245 register_reboot_notifier(&perf_reboot_notifier);
9247 ret = init_hw_breakpoint();
9248 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9250 /* do not patch jump label more than once per second */
9251 jump_label_rate_limit(&perf_sched_events, HZ);
9254 * Build time assertion that we keep the data_head at the intended
9255 * location. IOW, validation we got the __reserved[] size right.
9257 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9261 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9264 struct perf_pmu_events_attr *pmu_attr =
9265 container_of(attr, struct perf_pmu_events_attr, attr);
9267 if (pmu_attr->event_str)
9268 return sprintf(page, "%s\n", pmu_attr->event_str);
9273 static int __init perf_event_sysfs_init(void)
9278 mutex_lock(&pmus_lock);
9280 ret = bus_register(&pmu_bus);
9284 list_for_each_entry(pmu, &pmus, entry) {
9285 if (!pmu->name || pmu->type < 0)
9288 ret = pmu_dev_alloc(pmu);
9289 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9291 pmu_bus_running = 1;
9295 mutex_unlock(&pmus_lock);
9299 device_initcall(perf_event_sysfs_init);
9301 #ifdef CONFIG_CGROUP_PERF
9302 static struct cgroup_subsys_state *
9303 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9305 struct perf_cgroup *jc;
9307 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9309 return ERR_PTR(-ENOMEM);
9311 jc->info = alloc_percpu(struct perf_cgroup_info);
9314 return ERR_PTR(-ENOMEM);
9320 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9322 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9324 free_percpu(jc->info);
9328 static int __perf_cgroup_move(void *info)
9330 struct task_struct *task = info;
9331 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9335 static void perf_cgroup_attach(struct cgroup_subsys_state *css,
9336 struct cgroup_taskset *tset)
9338 struct task_struct *task;
9340 cgroup_taskset_for_each(task, tset)
9341 task_function_call(task, __perf_cgroup_move, task);
9344 static void perf_cgroup_exit(struct cgroup_subsys_state *css,
9345 struct cgroup_subsys_state *old_css,
9346 struct task_struct *task)
9349 * cgroup_exit() is called in the copy_process() failure path.
9350 * Ignore this case since the task hasn't ran yet, this avoids
9351 * trying to poke a half freed task state from generic code.
9353 if (!(task->flags & PF_EXITING))
9356 task_function_call(task, __perf_cgroup_move, task);
9359 struct cgroup_subsys perf_event_cgrp_subsys = {
9360 .css_alloc = perf_cgroup_css_alloc,
9361 .css_free = perf_cgroup_css_free,
9362 .exit = perf_cgroup_exit,
9363 .attach = perf_cgroup_attach,
9365 #endif /* CONFIG_CGROUP_PERF */