2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
50 #include <asm/irq_regs.h>
52 static struct workqueue_struct *perf_wq;
54 typedef int (*remote_function_f)(void *);
56 struct remote_function_call {
57 struct task_struct *p;
58 remote_function_f func;
63 static void remote_function(void *data)
65 struct remote_function_call *tfc = data;
66 struct task_struct *p = tfc->p;
70 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
74 tfc->ret = tfc->func(tfc->info);
78 * task_function_call - call a function on the cpu on which a task runs
79 * @p: the task to evaluate
80 * @func: the function to be called
81 * @info: the function call argument
83 * Calls the function @func when the task is currently running. This might
84 * be on the current CPU, which just calls the function directly
86 * returns: @func return value, or
87 * -ESRCH - when the process isn't running
88 * -EAGAIN - when the process moved away
91 task_function_call(struct task_struct *p, remote_function_f func, void *info)
93 struct remote_function_call data = {
97 .ret = -ESRCH, /* No such (running) process */
101 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
107 * cpu_function_call - call a function on the cpu
108 * @func: the function to be called
109 * @info: the function call argument
111 * Calls the function @func on the remote cpu.
113 * returns: @func return value or -ENXIO when the cpu is offline
115 static int cpu_function_call(int cpu, remote_function_f func, void *info)
117 struct remote_function_call data = {
121 .ret = -ENXIO, /* No such CPU */
124 smp_call_function_single(cpu, remote_function, &data, 1);
129 #define EVENT_OWNER_KERNEL ((void *) -1)
131 static bool is_kernel_event(struct perf_event *event)
133 return event->owner == EVENT_OWNER_KERNEL;
136 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
137 PERF_FLAG_FD_OUTPUT |\
138 PERF_FLAG_PID_CGROUP |\
139 PERF_FLAG_FD_CLOEXEC)
142 * branch priv levels that need permission checks
144 #define PERF_SAMPLE_BRANCH_PERM_PLM \
145 (PERF_SAMPLE_BRANCH_KERNEL |\
146 PERF_SAMPLE_BRANCH_HV)
149 EVENT_FLEXIBLE = 0x1,
151 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
155 * perf_sched_events : >0 events exist
156 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
158 struct static_key_deferred perf_sched_events __read_mostly;
159 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
160 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
162 static atomic_t nr_mmap_events __read_mostly;
163 static atomic_t nr_comm_events __read_mostly;
164 static atomic_t nr_task_events __read_mostly;
165 static atomic_t nr_freq_events __read_mostly;
166 static atomic_t nr_switch_events __read_mostly;
168 static LIST_HEAD(pmus);
169 static DEFINE_MUTEX(pmus_lock);
170 static struct srcu_struct pmus_srcu;
173 * perf event paranoia level:
174 * -1 - not paranoid at all
175 * 0 - disallow raw tracepoint access for unpriv
176 * 1 - disallow cpu events for unpriv
177 * 2 - disallow kernel profiling for unpriv
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 static 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, event->ctx);
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, ctx);
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 static 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.
493 list_for_each_entry_rcu(pmu, &pmus, entry) {
494 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
495 if (cpuctx->unique_pmu != pmu)
496 continue; /* ensure we process each cpuctx once */
499 * perf_cgroup_events says at least one
500 * context on this CPU has cgroup events.
502 * ctx->nr_cgroups reports the number of cgroup
503 * events for a context.
505 if (cpuctx->ctx.nr_cgroups > 0) {
506 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
507 perf_pmu_disable(cpuctx->ctx.pmu);
509 if (mode & PERF_CGROUP_SWOUT) {
510 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
512 * must not be done before ctxswout due
513 * to event_filter_match() in event_sched_out()
518 if (mode & PERF_CGROUP_SWIN) {
519 WARN_ON_ONCE(cpuctx->cgrp);
521 * set cgrp before ctxsw in to allow
522 * event_filter_match() to not have to pass
524 * we pass the cpuctx->ctx to perf_cgroup_from_task()
525 * because cgorup events are only per-cpu
527 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx);
528 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
530 perf_pmu_enable(cpuctx->ctx.pmu);
531 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
535 local_irq_restore(flags);
538 static inline void perf_cgroup_sched_out(struct task_struct *task,
539 struct task_struct *next)
541 struct perf_cgroup *cgrp1;
542 struct perf_cgroup *cgrp2 = NULL;
546 * we come here when we know perf_cgroup_events > 0
547 * we do not need to pass the ctx here because we know
548 * we are holding the rcu lock
550 cgrp1 = perf_cgroup_from_task(task, NULL);
553 * next is NULL when called from perf_event_enable_on_exec()
554 * that will systematically cause a cgroup_switch()
557 cgrp2 = perf_cgroup_from_task(next, NULL);
560 * only schedule out current cgroup events if we know
561 * that we are switching to a different cgroup. Otherwise,
562 * do no touch the cgroup events.
565 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
570 static inline void perf_cgroup_sched_in(struct task_struct *prev,
571 struct task_struct *task)
573 struct perf_cgroup *cgrp1;
574 struct perf_cgroup *cgrp2 = NULL;
578 * we come here when we know perf_cgroup_events > 0
579 * we do not need to pass the ctx here because we know
580 * we are holding the rcu lock
582 cgrp1 = perf_cgroup_from_task(task, NULL);
584 /* prev can never be NULL */
585 cgrp2 = perf_cgroup_from_task(prev, NULL);
588 * only need to schedule in cgroup events if we are changing
589 * cgroup during ctxsw. Cgroup events were not scheduled
590 * out of ctxsw out if that was not the case.
593 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
598 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
599 struct perf_event_attr *attr,
600 struct perf_event *group_leader)
602 struct perf_cgroup *cgrp;
603 struct cgroup_subsys_state *css;
604 struct fd f = fdget(fd);
610 css = css_tryget_online_from_dir(f.file->f_path.dentry,
611 &perf_event_cgrp_subsys);
617 cgrp = container_of(css, struct perf_cgroup, css);
621 * all events in a group must monitor
622 * the same cgroup because a task belongs
623 * to only one perf cgroup at a time
625 if (group_leader && group_leader->cgrp != cgrp) {
626 perf_detach_cgroup(event);
635 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
637 struct perf_cgroup_info *t;
638 t = per_cpu_ptr(event->cgrp->info, event->cpu);
639 event->shadow_ctx_time = now - t->timestamp;
643 perf_cgroup_defer_enabled(struct perf_event *event)
646 * when the current task's perf cgroup does not match
647 * the event's, we need to remember to call the
648 * perf_mark_enable() function the first time a task with
649 * a matching perf cgroup is scheduled in.
651 if (is_cgroup_event(event) && !perf_cgroup_match(event))
652 event->cgrp_defer_enabled = 1;
656 perf_cgroup_mark_enabled(struct perf_event *event,
657 struct perf_event_context *ctx)
659 struct perf_event *sub;
660 u64 tstamp = perf_event_time(event);
662 if (!event->cgrp_defer_enabled)
665 event->cgrp_defer_enabled = 0;
667 event->tstamp_enabled = tstamp - event->total_time_enabled;
668 list_for_each_entry(sub, &event->sibling_list, group_entry) {
669 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
670 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
671 sub->cgrp_defer_enabled = 0;
675 #else /* !CONFIG_CGROUP_PERF */
678 perf_cgroup_match(struct perf_event *event)
683 static inline void perf_detach_cgroup(struct perf_event *event)
686 static inline int is_cgroup_event(struct perf_event *event)
691 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
696 static inline void update_cgrp_time_from_event(struct perf_event *event)
700 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
704 static inline void perf_cgroup_sched_out(struct task_struct *task,
705 struct task_struct *next)
709 static inline void perf_cgroup_sched_in(struct task_struct *prev,
710 struct task_struct *task)
714 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
715 struct perf_event_attr *attr,
716 struct perf_event *group_leader)
722 perf_cgroup_set_timestamp(struct task_struct *task,
723 struct perf_event_context *ctx)
728 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
733 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
737 static inline u64 perf_cgroup_event_time(struct perf_event *event)
743 perf_cgroup_defer_enabled(struct perf_event *event)
748 perf_cgroup_mark_enabled(struct perf_event *event,
749 struct perf_event_context *ctx)
755 * set default to be dependent on timer tick just
758 #define PERF_CPU_HRTIMER (1000 / HZ)
760 * function must be called with interrupts disbled
762 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
764 struct perf_cpu_context *cpuctx;
767 WARN_ON(!irqs_disabled());
769 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
770 rotations = perf_rotate_context(cpuctx);
772 raw_spin_lock(&cpuctx->hrtimer_lock);
774 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
776 cpuctx->hrtimer_active = 0;
777 raw_spin_unlock(&cpuctx->hrtimer_lock);
779 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
782 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
784 struct hrtimer *timer = &cpuctx->hrtimer;
785 struct pmu *pmu = cpuctx->ctx.pmu;
788 /* no multiplexing needed for SW PMU */
789 if (pmu->task_ctx_nr == perf_sw_context)
793 * check default is sane, if not set then force to
794 * default interval (1/tick)
796 interval = pmu->hrtimer_interval_ms;
798 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
800 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
802 raw_spin_lock_init(&cpuctx->hrtimer_lock);
803 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
804 timer->function = perf_mux_hrtimer_handler;
807 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
809 struct hrtimer *timer = &cpuctx->hrtimer;
810 struct pmu *pmu = cpuctx->ctx.pmu;
814 if (pmu->task_ctx_nr == perf_sw_context)
817 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
818 if (!cpuctx->hrtimer_active) {
819 cpuctx->hrtimer_active = 1;
820 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
821 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
823 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
828 void perf_pmu_disable(struct pmu *pmu)
830 int *count = this_cpu_ptr(pmu->pmu_disable_count);
832 pmu->pmu_disable(pmu);
835 void perf_pmu_enable(struct pmu *pmu)
837 int *count = this_cpu_ptr(pmu->pmu_disable_count);
839 pmu->pmu_enable(pmu);
842 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
845 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
846 * perf_event_task_tick() are fully serialized because they're strictly cpu
847 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
848 * disabled, while perf_event_task_tick is called from IRQ context.
850 static void perf_event_ctx_activate(struct perf_event_context *ctx)
852 struct list_head *head = this_cpu_ptr(&active_ctx_list);
854 WARN_ON(!irqs_disabled());
856 WARN_ON(!list_empty(&ctx->active_ctx_list));
858 list_add(&ctx->active_ctx_list, head);
861 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
863 WARN_ON(!irqs_disabled());
865 WARN_ON(list_empty(&ctx->active_ctx_list));
867 list_del_init(&ctx->active_ctx_list);
870 static void get_ctx(struct perf_event_context *ctx)
872 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
875 static void free_ctx(struct rcu_head *head)
877 struct perf_event_context *ctx;
879 ctx = container_of(head, struct perf_event_context, rcu_head);
880 kfree(ctx->task_ctx_data);
884 static void put_ctx(struct perf_event_context *ctx)
886 if (atomic_dec_and_test(&ctx->refcount)) {
888 put_ctx(ctx->parent_ctx);
890 put_task_struct(ctx->task);
891 call_rcu(&ctx->rcu_head, free_ctx);
896 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
897 * perf_pmu_migrate_context() we need some magic.
899 * Those places that change perf_event::ctx will hold both
900 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
902 * Lock ordering is by mutex address. There are two other sites where
903 * perf_event_context::mutex nests and those are:
905 * - perf_event_exit_task_context() [ child , 0 ]
906 * __perf_event_exit_task()
908 * put_event() [ parent, 1 ]
910 * - perf_event_init_context() [ parent, 0 ]
911 * inherit_task_group()
916 * perf_try_init_event() [ child , 1 ]
918 * While it appears there is an obvious deadlock here -- the parent and child
919 * nesting levels are inverted between the two. This is in fact safe because
920 * life-time rules separate them. That is an exiting task cannot fork, and a
921 * spawning task cannot (yet) exit.
923 * But remember that that these are parent<->child context relations, and
924 * migration does not affect children, therefore these two orderings should not
927 * The change in perf_event::ctx does not affect children (as claimed above)
928 * because the sys_perf_event_open() case will install a new event and break
929 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
930 * concerned with cpuctx and that doesn't have children.
932 * The places that change perf_event::ctx will issue:
934 * perf_remove_from_context();
936 * perf_install_in_context();
938 * to affect the change. The remove_from_context() + synchronize_rcu() should
939 * quiesce the event, after which we can install it in the new location. This
940 * means that only external vectors (perf_fops, prctl) can perturb the event
941 * while in transit. Therefore all such accessors should also acquire
942 * perf_event_context::mutex to serialize against this.
944 * However; because event->ctx can change while we're waiting to acquire
945 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
950 * task_struct::perf_event_mutex
951 * perf_event_context::mutex
952 * perf_event_context::lock
953 * perf_event::child_mutex;
954 * perf_event::mmap_mutex
957 static struct perf_event_context *
958 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
960 struct perf_event_context *ctx;
964 ctx = ACCESS_ONCE(event->ctx);
965 if (!atomic_inc_not_zero(&ctx->refcount)) {
971 mutex_lock_nested(&ctx->mutex, nesting);
972 if (event->ctx != ctx) {
973 mutex_unlock(&ctx->mutex);
981 static inline struct perf_event_context *
982 perf_event_ctx_lock(struct perf_event *event)
984 return perf_event_ctx_lock_nested(event, 0);
987 static void perf_event_ctx_unlock(struct perf_event *event,
988 struct perf_event_context *ctx)
990 mutex_unlock(&ctx->mutex);
995 * This must be done under the ctx->lock, such as to serialize against
996 * context_equiv(), therefore we cannot call put_ctx() since that might end up
997 * calling scheduler related locks and ctx->lock nests inside those.
999 static __must_check struct perf_event_context *
1000 unclone_ctx(struct perf_event_context *ctx)
1002 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1004 lockdep_assert_held(&ctx->lock);
1007 ctx->parent_ctx = NULL;
1013 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1016 * only top level events have the pid namespace they were created in
1019 event = event->parent;
1021 return task_tgid_nr_ns(p, event->ns);
1024 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1027 * only top level events have the pid namespace they were created in
1030 event = event->parent;
1032 return task_pid_nr_ns(p, event->ns);
1036 * If we inherit events we want to return the parent event id
1039 static u64 primary_event_id(struct perf_event *event)
1044 id = event->parent->id;
1050 * Get the perf_event_context for a task and lock it.
1051 * This has to cope with with the fact that until it is locked,
1052 * the context could get moved to another task.
1054 static struct perf_event_context *
1055 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1057 struct perf_event_context *ctx;
1061 * One of the few rules of preemptible RCU is that one cannot do
1062 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1063 * part of the read side critical section was irqs-enabled -- see
1064 * rcu_read_unlock_special().
1066 * Since ctx->lock nests under rq->lock we must ensure the entire read
1067 * side critical section has interrupts disabled.
1069 local_irq_save(*flags);
1071 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1074 * If this context is a clone of another, it might
1075 * get swapped for another underneath us by
1076 * perf_event_task_sched_out, though the
1077 * rcu_read_lock() protects us from any context
1078 * getting freed. Lock the context and check if it
1079 * got swapped before we could get the lock, and retry
1080 * if so. If we locked the right context, then it
1081 * can't get swapped on us any more.
1083 raw_spin_lock(&ctx->lock);
1084 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1085 raw_spin_unlock(&ctx->lock);
1087 local_irq_restore(*flags);
1091 if (!atomic_inc_not_zero(&ctx->refcount)) {
1092 raw_spin_unlock(&ctx->lock);
1098 local_irq_restore(*flags);
1103 * Get the context for a task and increment its pin_count so it
1104 * can't get swapped to another task. This also increments its
1105 * reference count so that the context can't get freed.
1107 static struct perf_event_context *
1108 perf_pin_task_context(struct task_struct *task, int ctxn)
1110 struct perf_event_context *ctx;
1111 unsigned long flags;
1113 ctx = perf_lock_task_context(task, ctxn, &flags);
1116 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1121 static void perf_unpin_context(struct perf_event_context *ctx)
1123 unsigned long flags;
1125 raw_spin_lock_irqsave(&ctx->lock, flags);
1127 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1131 * Update the record of the current time in a context.
1133 static void update_context_time(struct perf_event_context *ctx)
1135 u64 now = perf_clock();
1137 ctx->time += now - ctx->timestamp;
1138 ctx->timestamp = now;
1141 static u64 perf_event_time(struct perf_event *event)
1143 struct perf_event_context *ctx = event->ctx;
1145 if (is_cgroup_event(event))
1146 return perf_cgroup_event_time(event);
1148 return ctx ? ctx->time : 0;
1152 * Update the total_time_enabled and total_time_running fields for a event.
1153 * The caller of this function needs to hold the ctx->lock.
1155 static void update_event_times(struct perf_event *event)
1157 struct perf_event_context *ctx = event->ctx;
1160 if (event->state < PERF_EVENT_STATE_INACTIVE ||
1161 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1164 * in cgroup mode, time_enabled represents
1165 * the time the event was enabled AND active
1166 * tasks were in the monitored cgroup. This is
1167 * independent of the activity of the context as
1168 * there may be a mix of cgroup and non-cgroup events.
1170 * That is why we treat cgroup events differently
1173 if (is_cgroup_event(event))
1174 run_end = perf_cgroup_event_time(event);
1175 else if (ctx->is_active)
1176 run_end = ctx->time;
1178 run_end = event->tstamp_stopped;
1180 event->total_time_enabled = run_end - event->tstamp_enabled;
1182 if (event->state == PERF_EVENT_STATE_INACTIVE)
1183 run_end = event->tstamp_stopped;
1185 run_end = perf_event_time(event);
1187 event->total_time_running = run_end - event->tstamp_running;
1192 * Update total_time_enabled and total_time_running for all events in a group.
1194 static void update_group_times(struct perf_event *leader)
1196 struct perf_event *event;
1198 update_event_times(leader);
1199 list_for_each_entry(event, &leader->sibling_list, group_entry)
1200 update_event_times(event);
1203 static struct list_head *
1204 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1206 if (event->attr.pinned)
1207 return &ctx->pinned_groups;
1209 return &ctx->flexible_groups;
1213 * Add a event from the lists for its context.
1214 * Must be called with ctx->mutex and ctx->lock held.
1217 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1219 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1220 event->attach_state |= PERF_ATTACH_CONTEXT;
1223 * If we're a stand alone event or group leader, we go to the context
1224 * list, group events are kept attached to the group so that
1225 * perf_group_detach can, at all times, locate all siblings.
1227 if (event->group_leader == event) {
1228 struct list_head *list;
1230 if (is_software_event(event))
1231 event->group_flags |= PERF_GROUP_SOFTWARE;
1233 list = ctx_group_list(event, ctx);
1234 list_add_tail(&event->group_entry, list);
1237 if (is_cgroup_event(event))
1240 list_add_rcu(&event->event_entry, &ctx->event_list);
1242 if (event->attr.inherit_stat)
1249 * Initialize event state based on the perf_event_attr::disabled.
1251 static inline void perf_event__state_init(struct perf_event *event)
1253 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1254 PERF_EVENT_STATE_INACTIVE;
1257 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1259 int entry = sizeof(u64); /* value */
1263 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1264 size += sizeof(u64);
1266 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1267 size += sizeof(u64);
1269 if (event->attr.read_format & PERF_FORMAT_ID)
1270 entry += sizeof(u64);
1272 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1274 size += sizeof(u64);
1278 event->read_size = size;
1281 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1283 struct perf_sample_data *data;
1286 if (sample_type & PERF_SAMPLE_IP)
1287 size += sizeof(data->ip);
1289 if (sample_type & PERF_SAMPLE_ADDR)
1290 size += sizeof(data->addr);
1292 if (sample_type & PERF_SAMPLE_PERIOD)
1293 size += sizeof(data->period);
1295 if (sample_type & PERF_SAMPLE_WEIGHT)
1296 size += sizeof(data->weight);
1298 if (sample_type & PERF_SAMPLE_READ)
1299 size += event->read_size;
1301 if (sample_type & PERF_SAMPLE_DATA_SRC)
1302 size += sizeof(data->data_src.val);
1304 if (sample_type & PERF_SAMPLE_TRANSACTION)
1305 size += sizeof(data->txn);
1307 event->header_size = size;
1311 * Called at perf_event creation and when events are attached/detached from a
1314 static void perf_event__header_size(struct perf_event *event)
1316 __perf_event_read_size(event,
1317 event->group_leader->nr_siblings);
1318 __perf_event_header_size(event, event->attr.sample_type);
1321 static void perf_event__id_header_size(struct perf_event *event)
1323 struct perf_sample_data *data;
1324 u64 sample_type = event->attr.sample_type;
1327 if (sample_type & PERF_SAMPLE_TID)
1328 size += sizeof(data->tid_entry);
1330 if (sample_type & PERF_SAMPLE_TIME)
1331 size += sizeof(data->time);
1333 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1334 size += sizeof(data->id);
1336 if (sample_type & PERF_SAMPLE_ID)
1337 size += sizeof(data->id);
1339 if (sample_type & PERF_SAMPLE_STREAM_ID)
1340 size += sizeof(data->stream_id);
1342 if (sample_type & PERF_SAMPLE_CPU)
1343 size += sizeof(data->cpu_entry);
1345 event->id_header_size = size;
1348 static bool perf_event_validate_size(struct perf_event *event)
1351 * The values computed here will be over-written when we actually
1354 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1355 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1356 perf_event__id_header_size(event);
1359 * Sum the lot; should not exceed the 64k limit we have on records.
1360 * Conservative limit to allow for callchains and other variable fields.
1362 if (event->read_size + event->header_size +
1363 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1369 static void perf_group_attach(struct perf_event *event)
1371 struct perf_event *group_leader = event->group_leader, *pos;
1374 * We can have double attach due to group movement in perf_event_open.
1376 if (event->attach_state & PERF_ATTACH_GROUP)
1379 event->attach_state |= PERF_ATTACH_GROUP;
1381 if (group_leader == event)
1384 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1386 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1387 !is_software_event(event))
1388 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1390 list_add_tail(&event->group_entry, &group_leader->sibling_list);
1391 group_leader->nr_siblings++;
1393 perf_event__header_size(group_leader);
1395 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1396 perf_event__header_size(pos);
1400 * Remove a event from the lists for its context.
1401 * Must be called with ctx->mutex and ctx->lock held.
1404 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1406 struct perf_cpu_context *cpuctx;
1408 WARN_ON_ONCE(event->ctx != ctx);
1409 lockdep_assert_held(&ctx->lock);
1412 * We can have double detach due to exit/hot-unplug + close.
1414 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1417 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1419 if (is_cgroup_event(event)) {
1421 cpuctx = __get_cpu_context(ctx);
1423 * if there are no more cgroup events
1424 * then cler cgrp to avoid stale pointer
1425 * in update_cgrp_time_from_cpuctx()
1427 if (!ctx->nr_cgroups)
1428 cpuctx->cgrp = NULL;
1432 if (event->attr.inherit_stat)
1435 list_del_rcu(&event->event_entry);
1437 if (event->group_leader == event)
1438 list_del_init(&event->group_entry);
1440 update_group_times(event);
1443 * If event was in error state, then keep it
1444 * that way, otherwise bogus counts will be
1445 * returned on read(). The only way to get out
1446 * of error state is by explicit re-enabling
1449 if (event->state > PERF_EVENT_STATE_OFF)
1450 event->state = PERF_EVENT_STATE_OFF;
1455 static void perf_group_detach(struct perf_event *event)
1457 struct perf_event *sibling, *tmp;
1458 struct list_head *list = NULL;
1461 * We can have double detach due to exit/hot-unplug + close.
1463 if (!(event->attach_state & PERF_ATTACH_GROUP))
1466 event->attach_state &= ~PERF_ATTACH_GROUP;
1469 * If this is a sibling, remove it from its group.
1471 if (event->group_leader != event) {
1472 list_del_init(&event->group_entry);
1473 event->group_leader->nr_siblings--;
1477 if (!list_empty(&event->group_entry))
1478 list = &event->group_entry;
1481 * If this was a group event with sibling events then
1482 * upgrade the siblings to singleton events by adding them
1483 * to whatever list we are on.
1485 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1487 list_move_tail(&sibling->group_entry, list);
1488 sibling->group_leader = sibling;
1490 /* Inherit group flags from the previous leader */
1491 sibling->group_flags = event->group_flags;
1493 WARN_ON_ONCE(sibling->ctx != event->ctx);
1497 perf_event__header_size(event->group_leader);
1499 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1500 perf_event__header_size(tmp);
1504 * User event without the task.
1506 static bool is_orphaned_event(struct perf_event *event)
1508 return event && !is_kernel_event(event) && !event->owner;
1512 * Event has a parent but parent's task finished and it's
1513 * alive only because of children holding refference.
1515 static bool is_orphaned_child(struct perf_event *event)
1517 return is_orphaned_event(event->parent);
1520 static void orphans_remove_work(struct work_struct *work);
1522 static void schedule_orphans_remove(struct perf_event_context *ctx)
1524 if (!ctx->task || ctx->orphans_remove_sched || !perf_wq)
1527 if (queue_delayed_work(perf_wq, &ctx->orphans_remove, 1)) {
1529 ctx->orphans_remove_sched = true;
1533 static int __init perf_workqueue_init(void)
1535 perf_wq = create_singlethread_workqueue("perf");
1536 WARN(!perf_wq, "failed to create perf workqueue\n");
1537 return perf_wq ? 0 : -1;
1540 core_initcall(perf_workqueue_init);
1542 static inline int __pmu_filter_match(struct perf_event *event)
1544 struct pmu *pmu = event->pmu;
1545 return pmu->filter_match ? pmu->filter_match(event) : 1;
1549 * Check whether we should attempt to schedule an event group based on
1550 * PMU-specific filtering. An event group can consist of HW and SW events,
1551 * potentially with a SW leader, so we must check all the filters, to
1552 * determine whether a group is schedulable:
1554 static inline int pmu_filter_match(struct perf_event *event)
1556 struct perf_event *child;
1558 if (!__pmu_filter_match(event))
1561 list_for_each_entry(child, &event->sibling_list, group_entry) {
1562 if (!__pmu_filter_match(child))
1570 event_filter_match(struct perf_event *event)
1572 return (event->cpu == -1 || event->cpu == smp_processor_id())
1573 && perf_cgroup_match(event) && pmu_filter_match(event);
1577 event_sched_out(struct perf_event *event,
1578 struct perf_cpu_context *cpuctx,
1579 struct perf_event_context *ctx)
1581 u64 tstamp = perf_event_time(event);
1584 WARN_ON_ONCE(event->ctx != ctx);
1585 lockdep_assert_held(&ctx->lock);
1588 * An event which could not be activated because of
1589 * filter mismatch still needs to have its timings
1590 * maintained, otherwise bogus information is return
1591 * via read() for time_enabled, time_running:
1593 if (event->state == PERF_EVENT_STATE_INACTIVE
1594 && !event_filter_match(event)) {
1595 delta = tstamp - event->tstamp_stopped;
1596 event->tstamp_running += delta;
1597 event->tstamp_stopped = tstamp;
1600 if (event->state != PERF_EVENT_STATE_ACTIVE)
1603 perf_pmu_disable(event->pmu);
1605 event->tstamp_stopped = tstamp;
1606 event->pmu->del(event, 0);
1608 event->state = PERF_EVENT_STATE_INACTIVE;
1609 if (event->pending_disable) {
1610 event->pending_disable = 0;
1611 event->state = PERF_EVENT_STATE_OFF;
1614 if (!is_software_event(event))
1615 cpuctx->active_oncpu--;
1616 if (!--ctx->nr_active)
1617 perf_event_ctx_deactivate(ctx);
1618 if (event->attr.freq && event->attr.sample_freq)
1620 if (event->attr.exclusive || !cpuctx->active_oncpu)
1621 cpuctx->exclusive = 0;
1623 if (is_orphaned_child(event))
1624 schedule_orphans_remove(ctx);
1626 perf_pmu_enable(event->pmu);
1630 group_sched_out(struct perf_event *group_event,
1631 struct perf_cpu_context *cpuctx,
1632 struct perf_event_context *ctx)
1634 struct perf_event *event;
1635 int state = group_event->state;
1637 event_sched_out(group_event, cpuctx, ctx);
1640 * Schedule out siblings (if any):
1642 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1643 event_sched_out(event, cpuctx, ctx);
1645 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1646 cpuctx->exclusive = 0;
1649 struct remove_event {
1650 struct perf_event *event;
1655 * Cross CPU call to remove a performance event
1657 * We disable the event on the hardware level first. After that we
1658 * remove it from the context list.
1660 static int __perf_remove_from_context(void *info)
1662 struct remove_event *re = info;
1663 struct perf_event *event = re->event;
1664 struct perf_event_context *ctx = event->ctx;
1665 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1667 raw_spin_lock(&ctx->lock);
1668 event_sched_out(event, cpuctx, ctx);
1669 if (re->detach_group)
1670 perf_group_detach(event);
1671 list_del_event(event, ctx);
1672 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1674 cpuctx->task_ctx = NULL;
1676 raw_spin_unlock(&ctx->lock);
1683 * Remove the event from a task's (or a CPU's) list of events.
1685 * CPU events are removed with a smp call. For task events we only
1686 * call when the task is on a CPU.
1688 * If event->ctx is a cloned context, callers must make sure that
1689 * every task struct that event->ctx->task could possibly point to
1690 * remains valid. This is OK when called from perf_release since
1691 * that only calls us on the top-level context, which can't be a clone.
1692 * When called from perf_event_exit_task, it's OK because the
1693 * context has been detached from its task.
1695 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1697 struct perf_event_context *ctx = event->ctx;
1698 struct task_struct *task = ctx->task;
1699 struct remove_event re = {
1701 .detach_group = detach_group,
1704 lockdep_assert_held(&ctx->mutex);
1708 * Per cpu events are removed via an smp call. The removal can
1709 * fail if the CPU is currently offline, but in that case we
1710 * already called __perf_remove_from_context from
1711 * perf_event_exit_cpu.
1713 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1718 if (!task_function_call(task, __perf_remove_from_context, &re))
1721 raw_spin_lock_irq(&ctx->lock);
1723 * If we failed to find a running task, but find the context active now
1724 * that we've acquired the ctx->lock, retry.
1726 if (ctx->is_active) {
1727 raw_spin_unlock_irq(&ctx->lock);
1729 * Reload the task pointer, it might have been changed by
1730 * a concurrent perf_event_context_sched_out().
1737 * Since the task isn't running, its safe to remove the event, us
1738 * holding the ctx->lock ensures the task won't get scheduled in.
1741 perf_group_detach(event);
1742 list_del_event(event, ctx);
1743 raw_spin_unlock_irq(&ctx->lock);
1747 * Cross CPU call to disable a performance event
1749 int __perf_event_disable(void *info)
1751 struct perf_event *event = info;
1752 struct perf_event_context *ctx = event->ctx;
1753 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1756 * If this is a per-task event, need to check whether this
1757 * event's task is the current task on this cpu.
1759 * Can trigger due to concurrent perf_event_context_sched_out()
1760 * flipping contexts around.
1762 if (ctx->task && cpuctx->task_ctx != ctx)
1765 raw_spin_lock(&ctx->lock);
1768 * If the event is on, turn it off.
1769 * If it is in error state, leave it in error state.
1771 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1772 update_context_time(ctx);
1773 update_cgrp_time_from_event(event);
1774 update_group_times(event);
1775 if (event == event->group_leader)
1776 group_sched_out(event, cpuctx, ctx);
1778 event_sched_out(event, cpuctx, ctx);
1779 event->state = PERF_EVENT_STATE_OFF;
1782 raw_spin_unlock(&ctx->lock);
1790 * If event->ctx is a cloned context, callers must make sure that
1791 * every task struct that event->ctx->task could possibly point to
1792 * remains valid. This condition is satisifed when called through
1793 * perf_event_for_each_child or perf_event_for_each because they
1794 * hold the top-level event's child_mutex, so any descendant that
1795 * goes to exit will block in sync_child_event.
1796 * When called from perf_pending_event it's OK because event->ctx
1797 * is the current context on this CPU and preemption is disabled,
1798 * hence we can't get into perf_event_task_sched_out for this context.
1800 static void _perf_event_disable(struct perf_event *event)
1802 struct perf_event_context *ctx = event->ctx;
1803 struct task_struct *task = ctx->task;
1807 * Disable the event on the cpu that it's on
1809 cpu_function_call(event->cpu, __perf_event_disable, event);
1814 if (!task_function_call(task, __perf_event_disable, event))
1817 raw_spin_lock_irq(&ctx->lock);
1819 * If the event is still active, we need to retry the cross-call.
1821 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1822 raw_spin_unlock_irq(&ctx->lock);
1824 * Reload the task pointer, it might have been changed by
1825 * a concurrent perf_event_context_sched_out().
1832 * Since we have the lock this context can't be scheduled
1833 * in, so we can change the state safely.
1835 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1836 update_group_times(event);
1837 event->state = PERF_EVENT_STATE_OFF;
1839 raw_spin_unlock_irq(&ctx->lock);
1843 * Strictly speaking kernel users cannot create groups and therefore this
1844 * interface does not need the perf_event_ctx_lock() magic.
1846 void perf_event_disable(struct perf_event *event)
1848 struct perf_event_context *ctx;
1850 ctx = perf_event_ctx_lock(event);
1851 _perf_event_disable(event);
1852 perf_event_ctx_unlock(event, ctx);
1854 EXPORT_SYMBOL_GPL(perf_event_disable);
1856 static void perf_set_shadow_time(struct perf_event *event,
1857 struct perf_event_context *ctx,
1861 * use the correct time source for the time snapshot
1863 * We could get by without this by leveraging the
1864 * fact that to get to this function, the caller
1865 * has most likely already called update_context_time()
1866 * and update_cgrp_time_xx() and thus both timestamp
1867 * are identical (or very close). Given that tstamp is,
1868 * already adjusted for cgroup, we could say that:
1869 * tstamp - ctx->timestamp
1871 * tstamp - cgrp->timestamp.
1873 * Then, in perf_output_read(), the calculation would
1874 * work with no changes because:
1875 * - event is guaranteed scheduled in
1876 * - no scheduled out in between
1877 * - thus the timestamp would be the same
1879 * But this is a bit hairy.
1881 * So instead, we have an explicit cgroup call to remain
1882 * within the time time source all along. We believe it
1883 * is cleaner and simpler to understand.
1885 if (is_cgroup_event(event))
1886 perf_cgroup_set_shadow_time(event, tstamp);
1888 event->shadow_ctx_time = tstamp - ctx->timestamp;
1891 #define MAX_INTERRUPTS (~0ULL)
1893 static void perf_log_throttle(struct perf_event *event, int enable);
1894 static void perf_log_itrace_start(struct perf_event *event);
1897 event_sched_in(struct perf_event *event,
1898 struct perf_cpu_context *cpuctx,
1899 struct perf_event_context *ctx)
1901 u64 tstamp = perf_event_time(event);
1904 lockdep_assert_held(&ctx->lock);
1906 if (event->state <= PERF_EVENT_STATE_OFF)
1909 WRITE_ONCE(event->oncpu, smp_processor_id());
1911 * Order event::oncpu write to happen before the ACTIVE state
1915 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1918 * Unthrottle events, since we scheduled we might have missed several
1919 * ticks already, also for a heavily scheduling task there is little
1920 * guarantee it'll get a tick in a timely manner.
1922 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1923 perf_log_throttle(event, 1);
1924 event->hw.interrupts = 0;
1928 * The new state must be visible before we turn it on in the hardware:
1932 perf_pmu_disable(event->pmu);
1934 perf_set_shadow_time(event, ctx, tstamp);
1936 perf_log_itrace_start(event);
1938 if (event->pmu->add(event, PERF_EF_START)) {
1939 event->state = PERF_EVENT_STATE_INACTIVE;
1945 event->tstamp_running += tstamp - event->tstamp_stopped;
1947 if (!is_software_event(event))
1948 cpuctx->active_oncpu++;
1949 if (!ctx->nr_active++)
1950 perf_event_ctx_activate(ctx);
1951 if (event->attr.freq && event->attr.sample_freq)
1954 if (event->attr.exclusive)
1955 cpuctx->exclusive = 1;
1957 if (is_orphaned_child(event))
1958 schedule_orphans_remove(ctx);
1961 perf_pmu_enable(event->pmu);
1967 group_sched_in(struct perf_event *group_event,
1968 struct perf_cpu_context *cpuctx,
1969 struct perf_event_context *ctx)
1971 struct perf_event *event, *partial_group = NULL;
1972 struct pmu *pmu = ctx->pmu;
1973 u64 now = ctx->time;
1974 bool simulate = false;
1976 if (group_event->state == PERF_EVENT_STATE_OFF)
1979 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1981 if (event_sched_in(group_event, cpuctx, ctx)) {
1982 pmu->cancel_txn(pmu);
1983 perf_mux_hrtimer_restart(cpuctx);
1988 * Schedule in siblings as one group (if any):
1990 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1991 if (event_sched_in(event, cpuctx, ctx)) {
1992 partial_group = event;
1997 if (!pmu->commit_txn(pmu))
2002 * Groups can be scheduled in as one unit only, so undo any
2003 * partial group before returning:
2004 * The events up to the failed event are scheduled out normally,
2005 * tstamp_stopped will be updated.
2007 * The failed events and the remaining siblings need to have
2008 * their timings updated as if they had gone thru event_sched_in()
2009 * and event_sched_out(). This is required to get consistent timings
2010 * across the group. This also takes care of the case where the group
2011 * could never be scheduled by ensuring tstamp_stopped is set to mark
2012 * the time the event was actually stopped, such that time delta
2013 * calculation in update_event_times() is correct.
2015 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
2016 if (event == partial_group)
2020 event->tstamp_running += now - event->tstamp_stopped;
2021 event->tstamp_stopped = now;
2023 event_sched_out(event, cpuctx, ctx);
2026 event_sched_out(group_event, cpuctx, ctx);
2028 pmu->cancel_txn(pmu);
2030 perf_mux_hrtimer_restart(cpuctx);
2036 * Work out whether we can put this event group on the CPU now.
2038 static int group_can_go_on(struct perf_event *event,
2039 struct perf_cpu_context *cpuctx,
2043 * Groups consisting entirely of software events can always go on.
2045 if (event->group_flags & PERF_GROUP_SOFTWARE)
2048 * If an exclusive group is already on, no other hardware
2051 if (cpuctx->exclusive)
2054 * If this group is exclusive and there are already
2055 * events on the CPU, it can't go on.
2057 if (event->attr.exclusive && cpuctx->active_oncpu)
2060 * Otherwise, try to add it if all previous groups were able
2066 static void add_event_to_ctx(struct perf_event *event,
2067 struct perf_event_context *ctx)
2069 u64 tstamp = perf_event_time(event);
2071 list_add_event(event, ctx);
2072 perf_group_attach(event);
2073 event->tstamp_enabled = tstamp;
2074 event->tstamp_running = tstamp;
2075 event->tstamp_stopped = tstamp;
2078 static void task_ctx_sched_out(struct perf_event_context *ctx);
2080 ctx_sched_in(struct perf_event_context *ctx,
2081 struct perf_cpu_context *cpuctx,
2082 enum event_type_t event_type,
2083 struct task_struct *task);
2085 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2086 struct perf_event_context *ctx,
2087 struct task_struct *task)
2089 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2091 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2092 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2094 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2098 * Cross CPU call to install and enable a performance event
2100 * Must be called with ctx->mutex held
2102 static int __perf_install_in_context(void *info)
2104 struct perf_event *event = info;
2105 struct perf_event_context *ctx = event->ctx;
2106 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2107 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2108 struct task_struct *task = current;
2110 perf_ctx_lock(cpuctx, task_ctx);
2111 perf_pmu_disable(cpuctx->ctx.pmu);
2114 * If there was an active task_ctx schedule it out.
2117 task_ctx_sched_out(task_ctx);
2120 * If the context we're installing events in is not the
2121 * active task_ctx, flip them.
2123 if (ctx->task && task_ctx != ctx) {
2125 raw_spin_unlock(&task_ctx->lock);
2126 raw_spin_lock(&ctx->lock);
2131 cpuctx->task_ctx = task_ctx;
2132 task = task_ctx->task;
2135 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2137 update_context_time(ctx);
2139 * update cgrp time only if current cgrp
2140 * matches event->cgrp. Must be done before
2141 * calling add_event_to_ctx()
2143 update_cgrp_time_from_event(event);
2145 add_event_to_ctx(event, ctx);
2148 * Schedule everything back in
2150 perf_event_sched_in(cpuctx, task_ctx, task);
2152 perf_pmu_enable(cpuctx->ctx.pmu);
2153 perf_ctx_unlock(cpuctx, task_ctx);
2159 * Attach a performance event to a context
2161 * First we add the event to the list with the hardware enable bit
2162 * in event->hw_config cleared.
2164 * If the event is attached to a task which is on a CPU we use a smp
2165 * call to enable it in the task context. The task might have been
2166 * scheduled away, but we check this in the smp call again.
2169 perf_install_in_context(struct perf_event_context *ctx,
2170 struct perf_event *event,
2173 struct task_struct *task = ctx->task;
2175 lockdep_assert_held(&ctx->mutex);
2178 if (event->cpu != -1)
2183 * Per cpu events are installed via an smp call and
2184 * the install is always successful.
2186 cpu_function_call(cpu, __perf_install_in_context, event);
2191 if (!task_function_call(task, __perf_install_in_context, event))
2194 raw_spin_lock_irq(&ctx->lock);
2196 * If we failed to find a running task, but find the context active now
2197 * that we've acquired the ctx->lock, retry.
2199 if (ctx->is_active) {
2200 raw_spin_unlock_irq(&ctx->lock);
2202 * Reload the task pointer, it might have been changed by
2203 * a concurrent perf_event_context_sched_out().
2210 * Since the task isn't running, its safe to add the event, us holding
2211 * the ctx->lock ensures the task won't get scheduled in.
2213 add_event_to_ctx(event, ctx);
2214 raw_spin_unlock_irq(&ctx->lock);
2218 * Put a event into inactive state and update time fields.
2219 * Enabling the leader of a group effectively enables all
2220 * the group members that aren't explicitly disabled, so we
2221 * have to update their ->tstamp_enabled also.
2222 * Note: this works for group members as well as group leaders
2223 * since the non-leader members' sibling_lists will be empty.
2225 static void __perf_event_mark_enabled(struct perf_event *event)
2227 struct perf_event *sub;
2228 u64 tstamp = perf_event_time(event);
2230 event->state = PERF_EVENT_STATE_INACTIVE;
2231 event->tstamp_enabled = tstamp - event->total_time_enabled;
2232 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2233 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2234 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2239 * Cross CPU call to enable a performance event
2241 static int __perf_event_enable(void *info)
2243 struct perf_event *event = info;
2244 struct perf_event_context *ctx = event->ctx;
2245 struct perf_event *leader = event->group_leader;
2246 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2250 * There's a time window between 'ctx->is_active' check
2251 * in perf_event_enable function and this place having:
2253 * - ctx->lock unlocked
2255 * where the task could be killed and 'ctx' deactivated
2256 * by perf_event_exit_task.
2258 if (!ctx->is_active)
2261 raw_spin_lock(&ctx->lock);
2262 update_context_time(ctx);
2264 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2268 * set current task's cgroup time reference point
2270 perf_cgroup_set_timestamp(current, ctx);
2272 __perf_event_mark_enabled(event);
2274 if (!event_filter_match(event)) {
2275 if (is_cgroup_event(event))
2276 perf_cgroup_defer_enabled(event);
2281 * If the event is in a group and isn't the group leader,
2282 * then don't put it on unless the group is on.
2284 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2287 if (!group_can_go_on(event, cpuctx, 1)) {
2290 if (event == leader)
2291 err = group_sched_in(event, cpuctx, ctx);
2293 err = event_sched_in(event, cpuctx, ctx);
2298 * If this event can't go on and it's part of a
2299 * group, then the whole group has to come off.
2301 if (leader != event) {
2302 group_sched_out(leader, cpuctx, ctx);
2303 perf_mux_hrtimer_restart(cpuctx);
2305 if (leader->attr.pinned) {
2306 update_group_times(leader);
2307 leader->state = PERF_EVENT_STATE_ERROR;
2312 raw_spin_unlock(&ctx->lock);
2320 * If event->ctx is a cloned context, callers must make sure that
2321 * every task struct that event->ctx->task could possibly point to
2322 * remains valid. This condition is satisfied when called through
2323 * perf_event_for_each_child or perf_event_for_each as described
2324 * for perf_event_disable.
2326 static void _perf_event_enable(struct perf_event *event)
2328 struct perf_event_context *ctx = event->ctx;
2329 struct task_struct *task = ctx->task;
2333 * Enable the event on the cpu that it's on
2335 cpu_function_call(event->cpu, __perf_event_enable, event);
2339 raw_spin_lock_irq(&ctx->lock);
2340 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2344 * If the event is in error state, clear that first.
2345 * That way, if we see the event in error state below, we
2346 * know that it has gone back into error state, as distinct
2347 * from the task having been scheduled away before the
2348 * cross-call arrived.
2350 if (event->state == PERF_EVENT_STATE_ERROR)
2351 event->state = PERF_EVENT_STATE_OFF;
2354 if (!ctx->is_active) {
2355 __perf_event_mark_enabled(event);
2359 raw_spin_unlock_irq(&ctx->lock);
2361 if (!task_function_call(task, __perf_event_enable, event))
2364 raw_spin_lock_irq(&ctx->lock);
2367 * If the context is active and the event is still off,
2368 * we need to retry the cross-call.
2370 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2372 * task could have been flipped by a concurrent
2373 * perf_event_context_sched_out()
2380 raw_spin_unlock_irq(&ctx->lock);
2384 * See perf_event_disable();
2386 void perf_event_enable(struct perf_event *event)
2388 struct perf_event_context *ctx;
2390 ctx = perf_event_ctx_lock(event);
2391 _perf_event_enable(event);
2392 perf_event_ctx_unlock(event, ctx);
2394 EXPORT_SYMBOL_GPL(perf_event_enable);
2396 static int __perf_event_stop(void *info)
2398 struct perf_event *event = info;
2400 /* for AUX events, our job is done if the event is already inactive */
2401 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2404 /* matches smp_wmb() in event_sched_in() */
2408 * There is a window with interrupts enabled before we get here,
2409 * so we need to check again lest we try to stop another CPU's event.
2411 if (READ_ONCE(event->oncpu) != smp_processor_id())
2414 event->pmu->stop(event, PERF_EF_UPDATE);
2419 static int _perf_event_refresh(struct perf_event *event, int refresh)
2422 * not supported on inherited events
2424 if (event->attr.inherit || !is_sampling_event(event))
2427 atomic_add(refresh, &event->event_limit);
2428 _perf_event_enable(event);
2434 * See perf_event_disable()
2436 int perf_event_refresh(struct perf_event *event, int refresh)
2438 struct perf_event_context *ctx;
2441 ctx = perf_event_ctx_lock(event);
2442 ret = _perf_event_refresh(event, refresh);
2443 perf_event_ctx_unlock(event, ctx);
2447 EXPORT_SYMBOL_GPL(perf_event_refresh);
2449 static void ctx_sched_out(struct perf_event_context *ctx,
2450 struct perf_cpu_context *cpuctx,
2451 enum event_type_t event_type)
2453 struct perf_event *event;
2454 int is_active = ctx->is_active;
2456 ctx->is_active &= ~event_type;
2457 if (likely(!ctx->nr_events))
2460 update_context_time(ctx);
2461 update_cgrp_time_from_cpuctx(cpuctx);
2462 if (!ctx->nr_active)
2465 perf_pmu_disable(ctx->pmu);
2466 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2467 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2468 group_sched_out(event, cpuctx, ctx);
2471 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2472 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2473 group_sched_out(event, cpuctx, ctx);
2475 perf_pmu_enable(ctx->pmu);
2479 * Test whether two contexts are equivalent, i.e. whether they have both been
2480 * cloned from the same version of the same context.
2482 * Equivalence is measured using a generation number in the context that is
2483 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2484 * and list_del_event().
2486 static int context_equiv(struct perf_event_context *ctx1,
2487 struct perf_event_context *ctx2)
2489 lockdep_assert_held(&ctx1->lock);
2490 lockdep_assert_held(&ctx2->lock);
2492 /* Pinning disables the swap optimization */
2493 if (ctx1->pin_count || ctx2->pin_count)
2496 /* If ctx1 is the parent of ctx2 */
2497 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2500 /* If ctx2 is the parent of ctx1 */
2501 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2505 * If ctx1 and ctx2 have the same parent; we flatten the parent
2506 * hierarchy, see perf_event_init_context().
2508 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2509 ctx1->parent_gen == ctx2->parent_gen)
2516 static void __perf_event_sync_stat(struct perf_event *event,
2517 struct perf_event *next_event)
2521 if (!event->attr.inherit_stat)
2525 * Update the event value, we cannot use perf_event_read()
2526 * because we're in the middle of a context switch and have IRQs
2527 * disabled, which upsets smp_call_function_single(), however
2528 * we know the event must be on the current CPU, therefore we
2529 * don't need to use it.
2531 switch (event->state) {
2532 case PERF_EVENT_STATE_ACTIVE:
2533 event->pmu->read(event);
2536 case PERF_EVENT_STATE_INACTIVE:
2537 update_event_times(event);
2545 * In order to keep per-task stats reliable we need to flip the event
2546 * values when we flip the contexts.
2548 value = local64_read(&next_event->count);
2549 value = local64_xchg(&event->count, value);
2550 local64_set(&next_event->count, value);
2552 swap(event->total_time_enabled, next_event->total_time_enabled);
2553 swap(event->total_time_running, next_event->total_time_running);
2556 * Since we swizzled the values, update the user visible data too.
2558 perf_event_update_userpage(event);
2559 perf_event_update_userpage(next_event);
2562 static void perf_event_sync_stat(struct perf_event_context *ctx,
2563 struct perf_event_context *next_ctx)
2565 struct perf_event *event, *next_event;
2570 update_context_time(ctx);
2572 event = list_first_entry(&ctx->event_list,
2573 struct perf_event, event_entry);
2575 next_event = list_first_entry(&next_ctx->event_list,
2576 struct perf_event, event_entry);
2578 while (&event->event_entry != &ctx->event_list &&
2579 &next_event->event_entry != &next_ctx->event_list) {
2581 __perf_event_sync_stat(event, next_event);
2583 event = list_next_entry(event, event_entry);
2584 next_event = list_next_entry(next_event, event_entry);
2588 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2589 struct task_struct *next)
2591 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2592 struct perf_event_context *next_ctx;
2593 struct perf_event_context *parent, *next_parent;
2594 struct perf_cpu_context *cpuctx;
2600 cpuctx = __get_cpu_context(ctx);
2601 if (!cpuctx->task_ctx)
2605 next_ctx = next->perf_event_ctxp[ctxn];
2609 parent = rcu_dereference(ctx->parent_ctx);
2610 next_parent = rcu_dereference(next_ctx->parent_ctx);
2612 /* If neither context have a parent context; they cannot be clones. */
2613 if (!parent && !next_parent)
2616 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2618 * Looks like the two contexts are clones, so we might be
2619 * able to optimize the context switch. We lock both
2620 * contexts and check that they are clones under the
2621 * lock (including re-checking that neither has been
2622 * uncloned in the meantime). It doesn't matter which
2623 * order we take the locks because no other cpu could
2624 * be trying to lock both of these tasks.
2626 raw_spin_lock(&ctx->lock);
2627 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2628 if (context_equiv(ctx, next_ctx)) {
2630 * XXX do we need a memory barrier of sorts
2631 * wrt to rcu_dereference() of perf_event_ctxp
2633 task->perf_event_ctxp[ctxn] = next_ctx;
2634 next->perf_event_ctxp[ctxn] = ctx;
2636 next_ctx->task = task;
2638 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2642 perf_event_sync_stat(ctx, next_ctx);
2644 raw_spin_unlock(&next_ctx->lock);
2645 raw_spin_unlock(&ctx->lock);
2651 raw_spin_lock(&ctx->lock);
2652 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2653 cpuctx->task_ctx = NULL;
2654 raw_spin_unlock(&ctx->lock);
2658 void perf_sched_cb_dec(struct pmu *pmu)
2660 this_cpu_dec(perf_sched_cb_usages);
2663 void perf_sched_cb_inc(struct pmu *pmu)
2665 this_cpu_inc(perf_sched_cb_usages);
2669 * This function provides the context switch callback to the lower code
2670 * layer. It is invoked ONLY when the context switch callback is enabled.
2672 static void perf_pmu_sched_task(struct task_struct *prev,
2673 struct task_struct *next,
2676 struct perf_cpu_context *cpuctx;
2678 unsigned long flags;
2683 local_irq_save(flags);
2687 list_for_each_entry_rcu(pmu, &pmus, entry) {
2688 if (pmu->sched_task) {
2689 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2691 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2693 perf_pmu_disable(pmu);
2695 pmu->sched_task(cpuctx->task_ctx, sched_in);
2697 perf_pmu_enable(pmu);
2699 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2705 local_irq_restore(flags);
2708 static void perf_event_switch(struct task_struct *task,
2709 struct task_struct *next_prev, bool sched_in);
2711 #define for_each_task_context_nr(ctxn) \
2712 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2715 * Called from scheduler to remove the events of the current task,
2716 * with interrupts disabled.
2718 * We stop each event and update the event value in event->count.
2720 * This does not protect us against NMI, but disable()
2721 * sets the disabled bit in the control field of event _before_
2722 * accessing the event control register. If a NMI hits, then it will
2723 * not restart the event.
2725 void __perf_event_task_sched_out(struct task_struct *task,
2726 struct task_struct *next)
2730 if (__this_cpu_read(perf_sched_cb_usages))
2731 perf_pmu_sched_task(task, next, false);
2733 if (atomic_read(&nr_switch_events))
2734 perf_event_switch(task, next, false);
2736 for_each_task_context_nr(ctxn)
2737 perf_event_context_sched_out(task, ctxn, next);
2740 * if cgroup events exist on this CPU, then we need
2741 * to check if we have to switch out PMU state.
2742 * cgroup event are system-wide mode only
2744 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2745 perf_cgroup_sched_out(task, next);
2748 static void task_ctx_sched_out(struct perf_event_context *ctx)
2750 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2752 if (!cpuctx->task_ctx)
2755 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2758 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2759 cpuctx->task_ctx = NULL;
2763 * Called with IRQs disabled
2765 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2766 enum event_type_t event_type)
2768 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2772 ctx_pinned_sched_in(struct perf_event_context *ctx,
2773 struct perf_cpu_context *cpuctx)
2775 struct perf_event *event;
2777 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2778 if (event->state <= PERF_EVENT_STATE_OFF)
2780 if (!event_filter_match(event))
2783 /* may need to reset tstamp_enabled */
2784 if (is_cgroup_event(event))
2785 perf_cgroup_mark_enabled(event, ctx);
2787 if (group_can_go_on(event, cpuctx, 1))
2788 group_sched_in(event, cpuctx, ctx);
2791 * If this pinned group hasn't been scheduled,
2792 * put it in error state.
2794 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2795 update_group_times(event);
2796 event->state = PERF_EVENT_STATE_ERROR;
2802 ctx_flexible_sched_in(struct perf_event_context *ctx,
2803 struct perf_cpu_context *cpuctx)
2805 struct perf_event *event;
2808 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2809 /* Ignore events in OFF or ERROR state */
2810 if (event->state <= PERF_EVENT_STATE_OFF)
2813 * Listen to the 'cpu' scheduling filter constraint
2816 if (!event_filter_match(event))
2819 /* may need to reset tstamp_enabled */
2820 if (is_cgroup_event(event))
2821 perf_cgroup_mark_enabled(event, ctx);
2823 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2824 if (group_sched_in(event, cpuctx, ctx))
2831 ctx_sched_in(struct perf_event_context *ctx,
2832 struct perf_cpu_context *cpuctx,
2833 enum event_type_t event_type,
2834 struct task_struct *task)
2837 int is_active = ctx->is_active;
2839 ctx->is_active |= event_type;
2840 if (likely(!ctx->nr_events))
2844 ctx->timestamp = now;
2845 perf_cgroup_set_timestamp(task, ctx);
2847 * First go through the list and put on any pinned groups
2848 * in order to give them the best chance of going on.
2850 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2851 ctx_pinned_sched_in(ctx, cpuctx);
2853 /* Then walk through the lower prio flexible groups */
2854 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2855 ctx_flexible_sched_in(ctx, cpuctx);
2858 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2859 enum event_type_t event_type,
2860 struct task_struct *task)
2862 struct perf_event_context *ctx = &cpuctx->ctx;
2864 ctx_sched_in(ctx, cpuctx, event_type, task);
2867 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2868 struct task_struct *task)
2870 struct perf_cpu_context *cpuctx;
2872 cpuctx = __get_cpu_context(ctx);
2873 if (cpuctx->task_ctx == ctx)
2876 perf_ctx_lock(cpuctx, ctx);
2877 perf_pmu_disable(ctx->pmu);
2879 * We want to keep the following priority order:
2880 * cpu pinned (that don't need to move), task pinned,
2881 * cpu flexible, task flexible.
2883 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2886 cpuctx->task_ctx = ctx;
2888 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2890 perf_pmu_enable(ctx->pmu);
2891 perf_ctx_unlock(cpuctx, ctx);
2895 * Called from scheduler to add the events of the current task
2896 * with interrupts disabled.
2898 * We restore the event value and then enable it.
2900 * This does not protect us against NMI, but enable()
2901 * sets the enabled bit in the control field of event _before_
2902 * accessing the event control register. If a NMI hits, then it will
2903 * keep the event running.
2905 void __perf_event_task_sched_in(struct task_struct *prev,
2906 struct task_struct *task)
2908 struct perf_event_context *ctx;
2911 for_each_task_context_nr(ctxn) {
2912 ctx = task->perf_event_ctxp[ctxn];
2916 perf_event_context_sched_in(ctx, task);
2919 * if cgroup events exist on this CPU, then we need
2920 * to check if we have to switch in PMU state.
2921 * cgroup event are system-wide mode only
2923 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2924 perf_cgroup_sched_in(prev, task);
2926 if (atomic_read(&nr_switch_events))
2927 perf_event_switch(task, prev, true);
2929 if (__this_cpu_read(perf_sched_cb_usages))
2930 perf_pmu_sched_task(prev, task, true);
2933 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2935 u64 frequency = event->attr.sample_freq;
2936 u64 sec = NSEC_PER_SEC;
2937 u64 divisor, dividend;
2939 int count_fls, nsec_fls, frequency_fls, sec_fls;
2941 count_fls = fls64(count);
2942 nsec_fls = fls64(nsec);
2943 frequency_fls = fls64(frequency);
2947 * We got @count in @nsec, with a target of sample_freq HZ
2948 * the target period becomes:
2951 * period = -------------------
2952 * @nsec * sample_freq
2957 * Reduce accuracy by one bit such that @a and @b converge
2958 * to a similar magnitude.
2960 #define REDUCE_FLS(a, b) \
2962 if (a##_fls > b##_fls) { \
2972 * Reduce accuracy until either term fits in a u64, then proceed with
2973 * the other, so that finally we can do a u64/u64 division.
2975 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2976 REDUCE_FLS(nsec, frequency);
2977 REDUCE_FLS(sec, count);
2980 if (count_fls + sec_fls > 64) {
2981 divisor = nsec * frequency;
2983 while (count_fls + sec_fls > 64) {
2984 REDUCE_FLS(count, sec);
2988 dividend = count * sec;
2990 dividend = count * sec;
2992 while (nsec_fls + frequency_fls > 64) {
2993 REDUCE_FLS(nsec, frequency);
2997 divisor = nsec * frequency;
3003 return div64_u64(dividend, divisor);
3006 static DEFINE_PER_CPU(int, perf_throttled_count);
3007 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3009 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3011 struct hw_perf_event *hwc = &event->hw;
3012 s64 period, sample_period;
3015 period = perf_calculate_period(event, nsec, count);
3017 delta = (s64)(period - hwc->sample_period);
3018 delta = (delta + 7) / 8; /* low pass filter */
3020 sample_period = hwc->sample_period + delta;
3025 hwc->sample_period = sample_period;
3027 if (local64_read(&hwc->period_left) > 8*sample_period) {
3029 event->pmu->stop(event, PERF_EF_UPDATE);
3031 local64_set(&hwc->period_left, 0);
3034 event->pmu->start(event, PERF_EF_RELOAD);
3039 * combine freq adjustment with unthrottling to avoid two passes over the
3040 * events. At the same time, make sure, having freq events does not change
3041 * the rate of unthrottling as that would introduce bias.
3043 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3046 struct perf_event *event;
3047 struct hw_perf_event *hwc;
3048 u64 now, period = TICK_NSEC;
3052 * only need to iterate over all events iff:
3053 * - context have events in frequency mode (needs freq adjust)
3054 * - there are events to unthrottle on this cpu
3056 if (!(ctx->nr_freq || needs_unthr))
3059 raw_spin_lock(&ctx->lock);
3060 perf_pmu_disable(ctx->pmu);
3062 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3063 if (event->state != PERF_EVENT_STATE_ACTIVE)
3066 if (!event_filter_match(event))
3069 perf_pmu_disable(event->pmu);
3073 if (hwc->interrupts == MAX_INTERRUPTS) {
3074 hwc->interrupts = 0;
3075 perf_log_throttle(event, 1);
3076 event->pmu->start(event, 0);
3079 if (!event->attr.freq || !event->attr.sample_freq)
3083 * stop the event and update event->count
3085 event->pmu->stop(event, PERF_EF_UPDATE);
3087 now = local64_read(&event->count);
3088 delta = now - hwc->freq_count_stamp;
3089 hwc->freq_count_stamp = now;
3093 * reload only if value has changed
3094 * we have stopped the event so tell that
3095 * to perf_adjust_period() to avoid stopping it
3099 perf_adjust_period(event, period, delta, false);
3101 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3103 perf_pmu_enable(event->pmu);
3106 perf_pmu_enable(ctx->pmu);
3107 raw_spin_unlock(&ctx->lock);
3111 * Round-robin a context's events:
3113 static void rotate_ctx(struct perf_event_context *ctx)
3116 * Rotate the first entry last of non-pinned groups. Rotation might be
3117 * disabled by the inheritance code.
3119 if (!ctx->rotate_disable)
3120 list_rotate_left(&ctx->flexible_groups);
3123 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3125 struct perf_event_context *ctx = NULL;
3128 if (cpuctx->ctx.nr_events) {
3129 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3133 ctx = cpuctx->task_ctx;
3134 if (ctx && ctx->nr_events) {
3135 if (ctx->nr_events != ctx->nr_active)
3142 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3143 perf_pmu_disable(cpuctx->ctx.pmu);
3145 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3147 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3149 rotate_ctx(&cpuctx->ctx);
3153 perf_event_sched_in(cpuctx, ctx, current);
3155 perf_pmu_enable(cpuctx->ctx.pmu);
3156 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3162 #ifdef CONFIG_NO_HZ_FULL
3163 bool perf_event_can_stop_tick(void)
3165 if (atomic_read(&nr_freq_events) ||
3166 __this_cpu_read(perf_throttled_count))
3173 void perf_event_task_tick(void)
3175 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3176 struct perf_event_context *ctx, *tmp;
3179 WARN_ON(!irqs_disabled());
3181 __this_cpu_inc(perf_throttled_seq);
3182 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3184 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3185 perf_adjust_freq_unthr_context(ctx, throttled);
3188 static int event_enable_on_exec(struct perf_event *event,
3189 struct perf_event_context *ctx)
3191 if (!event->attr.enable_on_exec)
3194 event->attr.enable_on_exec = 0;
3195 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3198 __perf_event_mark_enabled(event);
3204 * Enable all of a task's events that have been marked enable-on-exec.
3205 * This expects task == current.
3207 static void perf_event_enable_on_exec(int ctxn)
3209 struct perf_event_context *ctx, *clone_ctx = NULL;
3210 struct perf_event *event;
3211 unsigned long flags;
3215 local_irq_save(flags);
3216 ctx = current->perf_event_ctxp[ctxn];
3217 if (!ctx || !ctx->nr_events)
3221 * We must ctxsw out cgroup events to avoid conflict
3222 * when invoking perf_task_event_sched_in() later on
3223 * in this function. Otherwise we end up trying to
3224 * ctxswin cgroup events which are already scheduled
3227 perf_cgroup_sched_out(current, NULL);
3229 raw_spin_lock(&ctx->lock);
3230 task_ctx_sched_out(ctx);
3232 list_for_each_entry(event, &ctx->event_list, event_entry) {
3233 ret = event_enable_on_exec(event, ctx);
3239 * Unclone this context if we enabled any event.
3242 clone_ctx = unclone_ctx(ctx);
3244 raw_spin_unlock(&ctx->lock);
3247 * Also calls ctxswin for cgroup events, if any:
3249 perf_event_context_sched_in(ctx, ctx->task);
3251 local_irq_restore(flags);
3257 void perf_event_exec(void)
3262 for_each_task_context_nr(ctxn)
3263 perf_event_enable_on_exec(ctxn);
3267 struct perf_read_data {
3268 struct perf_event *event;
3274 * Cross CPU call to read the hardware event
3276 static void __perf_event_read(void *info)
3278 struct perf_read_data *data = info;
3279 struct perf_event *sub, *event = data->event;
3280 struct perf_event_context *ctx = event->ctx;
3281 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3282 struct pmu *pmu = event->pmu;
3285 * If this is a task context, we need to check whether it is
3286 * the current task context of this cpu. If not it has been
3287 * scheduled out before the smp call arrived. In that case
3288 * event->count would have been updated to a recent sample
3289 * when the event was scheduled out.
3291 if (ctx->task && cpuctx->task_ctx != ctx)
3294 raw_spin_lock(&ctx->lock);
3295 if (ctx->is_active) {
3296 update_context_time(ctx);
3297 update_cgrp_time_from_event(event);
3300 update_event_times(event);
3301 if (event->state != PERF_EVENT_STATE_ACTIVE)
3310 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3314 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3315 update_event_times(sub);
3316 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3318 * Use sibling's PMU rather than @event's since
3319 * sibling could be on different (eg: software) PMU.
3321 sub->pmu->read(sub);
3325 data->ret = pmu->commit_txn(pmu);
3328 raw_spin_unlock(&ctx->lock);
3331 static inline u64 perf_event_count(struct perf_event *event)
3333 if (event->pmu->count)
3334 return event->pmu->count(event);
3336 return __perf_event_count(event);
3340 * NMI-safe method to read a local event, that is an event that
3342 * - either for the current task, or for this CPU
3343 * - does not have inherit set, for inherited task events
3344 * will not be local and we cannot read them atomically
3345 * - must not have a pmu::count method
3347 u64 perf_event_read_local(struct perf_event *event)
3349 unsigned long flags;
3353 * Disabling interrupts avoids all counter scheduling (context
3354 * switches, timer based rotation and IPIs).
3356 local_irq_save(flags);
3358 /* If this is a per-task event, it must be for current */
3359 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3360 event->hw.target != current);
3362 /* If this is a per-CPU event, it must be for this CPU */
3363 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3364 event->cpu != smp_processor_id());
3367 * It must not be an event with inherit set, we cannot read
3368 * all child counters from atomic context.
3370 WARN_ON_ONCE(event->attr.inherit);
3373 * It must not have a pmu::count method, those are not
3376 WARN_ON_ONCE(event->pmu->count);
3379 * If the event is currently on this CPU, its either a per-task event,
3380 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3383 if (event->oncpu == smp_processor_id())
3384 event->pmu->read(event);
3386 val = local64_read(&event->count);
3387 local_irq_restore(flags);
3392 static int perf_event_read(struct perf_event *event, bool group)
3397 * If event is enabled and currently active on a CPU, update the
3398 * value in the event structure:
3400 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3401 struct perf_read_data data = {
3406 smp_call_function_single(event->oncpu,
3407 __perf_event_read, &data, 1);
3409 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3410 struct perf_event_context *ctx = event->ctx;
3411 unsigned long flags;
3413 raw_spin_lock_irqsave(&ctx->lock, flags);
3415 * may read while context is not active
3416 * (e.g., thread is blocked), in that case
3417 * we cannot update context time
3419 if (ctx->is_active) {
3420 update_context_time(ctx);
3421 update_cgrp_time_from_event(event);
3424 update_group_times(event);
3426 update_event_times(event);
3427 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3434 * Initialize the perf_event context in a task_struct:
3436 static void __perf_event_init_context(struct perf_event_context *ctx)
3438 raw_spin_lock_init(&ctx->lock);
3439 mutex_init(&ctx->mutex);
3440 INIT_LIST_HEAD(&ctx->active_ctx_list);
3441 INIT_LIST_HEAD(&ctx->pinned_groups);
3442 INIT_LIST_HEAD(&ctx->flexible_groups);
3443 INIT_LIST_HEAD(&ctx->event_list);
3444 atomic_set(&ctx->refcount, 1);
3445 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3448 static struct perf_event_context *
3449 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3451 struct perf_event_context *ctx;
3453 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3457 __perf_event_init_context(ctx);
3460 get_task_struct(task);
3467 static struct task_struct *
3468 find_lively_task_by_vpid(pid_t vpid)
3470 struct task_struct *task;
3476 task = find_task_by_vpid(vpid);
3478 get_task_struct(task);
3482 return ERR_PTR(-ESRCH);
3488 * Returns a matching context with refcount and pincount.
3490 static struct perf_event_context *
3491 find_get_context(struct pmu *pmu, struct task_struct *task,
3492 struct perf_event *event)
3494 struct perf_event_context *ctx, *clone_ctx = NULL;
3495 struct perf_cpu_context *cpuctx;
3496 void *task_ctx_data = NULL;
3497 unsigned long flags;
3499 int cpu = event->cpu;
3502 /* Must be root to operate on a CPU event: */
3503 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3504 return ERR_PTR(-EACCES);
3507 * We could be clever and allow to attach a event to an
3508 * offline CPU and activate it when the CPU comes up, but
3511 if (!cpu_online(cpu))
3512 return ERR_PTR(-ENODEV);
3514 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3523 ctxn = pmu->task_ctx_nr;
3527 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3528 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3529 if (!task_ctx_data) {
3536 ctx = perf_lock_task_context(task, ctxn, &flags);
3538 clone_ctx = unclone_ctx(ctx);
3541 if (task_ctx_data && !ctx->task_ctx_data) {
3542 ctx->task_ctx_data = task_ctx_data;
3543 task_ctx_data = NULL;
3545 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3550 ctx = alloc_perf_context(pmu, task);
3555 if (task_ctx_data) {
3556 ctx->task_ctx_data = task_ctx_data;
3557 task_ctx_data = NULL;
3561 mutex_lock(&task->perf_event_mutex);
3563 * If it has already passed perf_event_exit_task().
3564 * we must see PF_EXITING, it takes this mutex too.
3566 if (task->flags & PF_EXITING)
3568 else if (task->perf_event_ctxp[ctxn])
3573 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3575 mutex_unlock(&task->perf_event_mutex);
3577 if (unlikely(err)) {
3586 kfree(task_ctx_data);
3590 kfree(task_ctx_data);
3591 return ERR_PTR(err);
3594 static void perf_event_free_filter(struct perf_event *event);
3595 static void perf_event_free_bpf_prog(struct perf_event *event);
3597 static void free_event_rcu(struct rcu_head *head)
3599 struct perf_event *event;
3601 event = container_of(head, struct perf_event, rcu_head);
3603 put_pid_ns(event->ns);
3604 perf_event_free_filter(event);
3608 static void ring_buffer_attach(struct perf_event *event,
3609 struct ring_buffer *rb);
3611 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3616 if (is_cgroup_event(event))
3617 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3620 static void unaccount_event(struct perf_event *event)
3625 if (event->attach_state & PERF_ATTACH_TASK)
3626 static_key_slow_dec_deferred(&perf_sched_events);
3627 if (event->attr.mmap || event->attr.mmap_data)
3628 atomic_dec(&nr_mmap_events);
3629 if (event->attr.comm)
3630 atomic_dec(&nr_comm_events);
3631 if (event->attr.task)
3632 atomic_dec(&nr_task_events);
3633 if (event->attr.freq)
3634 atomic_dec(&nr_freq_events);
3635 if (event->attr.context_switch) {
3636 static_key_slow_dec_deferred(&perf_sched_events);
3637 atomic_dec(&nr_switch_events);
3639 if (is_cgroup_event(event))
3640 static_key_slow_dec_deferred(&perf_sched_events);
3641 if (has_branch_stack(event))
3642 static_key_slow_dec_deferred(&perf_sched_events);
3644 unaccount_event_cpu(event, event->cpu);
3648 * The following implement mutual exclusion of events on "exclusive" pmus
3649 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3650 * at a time, so we disallow creating events that might conflict, namely:
3652 * 1) cpu-wide events in the presence of per-task events,
3653 * 2) per-task events in the presence of cpu-wide events,
3654 * 3) two matching events on the same context.
3656 * The former two cases are handled in the allocation path (perf_event_alloc(),
3657 * __free_event()), the latter -- before the first perf_install_in_context().
3659 static int exclusive_event_init(struct perf_event *event)
3661 struct pmu *pmu = event->pmu;
3663 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3667 * Prevent co-existence of per-task and cpu-wide events on the
3668 * same exclusive pmu.
3670 * Negative pmu::exclusive_cnt means there are cpu-wide
3671 * events on this "exclusive" pmu, positive means there are
3674 * Since this is called in perf_event_alloc() path, event::ctx
3675 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3676 * to mean "per-task event", because unlike other attach states it
3677 * never gets cleared.
3679 if (event->attach_state & PERF_ATTACH_TASK) {
3680 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3683 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3690 static void exclusive_event_destroy(struct perf_event *event)
3692 struct pmu *pmu = event->pmu;
3694 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3697 /* see comment in exclusive_event_init() */
3698 if (event->attach_state & PERF_ATTACH_TASK)
3699 atomic_dec(&pmu->exclusive_cnt);
3701 atomic_inc(&pmu->exclusive_cnt);
3704 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3706 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3707 (e1->cpu == e2->cpu ||
3714 /* Called under the same ctx::mutex as perf_install_in_context() */
3715 static bool exclusive_event_installable(struct perf_event *event,
3716 struct perf_event_context *ctx)
3718 struct perf_event *iter_event;
3719 struct pmu *pmu = event->pmu;
3721 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3724 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3725 if (exclusive_event_match(iter_event, event))
3732 static void __free_event(struct perf_event *event)
3734 if (!event->parent) {
3735 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3736 put_callchain_buffers();
3739 perf_event_free_bpf_prog(event);
3742 event->destroy(event);
3744 if (event->pmu->free_drv_configs)
3745 event->pmu->free_drv_configs(event);
3748 put_ctx(event->ctx);
3751 exclusive_event_destroy(event);
3752 module_put(event->pmu->module);
3755 call_rcu(&event->rcu_head, free_event_rcu);
3758 static void _free_event(struct perf_event *event)
3760 irq_work_sync(&event->pending);
3762 unaccount_event(event);
3766 * Can happen when we close an event with re-directed output.
3768 * Since we have a 0 refcount, perf_mmap_close() will skip
3769 * over us; possibly making our ring_buffer_put() the last.
3771 mutex_lock(&event->mmap_mutex);
3772 ring_buffer_attach(event, NULL);
3773 mutex_unlock(&event->mmap_mutex);
3776 if (is_cgroup_event(event))
3777 perf_detach_cgroup(event);
3779 __free_event(event);
3783 * Used to free events which have a known refcount of 1, such as in error paths
3784 * where the event isn't exposed yet and inherited events.
3786 static void free_event(struct perf_event *event)
3788 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3789 "unexpected event refcount: %ld; ptr=%p\n",
3790 atomic_long_read(&event->refcount), event)) {
3791 /* leak to avoid use-after-free */
3799 * Remove user event from the owner task.
3801 static void perf_remove_from_owner(struct perf_event *event)
3803 struct task_struct *owner;
3806 owner = ACCESS_ONCE(event->owner);
3808 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3809 * !owner it means the list deletion is complete and we can indeed
3810 * free this event, otherwise we need to serialize on
3811 * owner->perf_event_mutex.
3813 smp_read_barrier_depends();
3816 * Since delayed_put_task_struct() also drops the last
3817 * task reference we can safely take a new reference
3818 * while holding the rcu_read_lock().
3820 get_task_struct(owner);
3826 * If we're here through perf_event_exit_task() we're already
3827 * holding ctx->mutex which would be an inversion wrt. the
3828 * normal lock order.
3830 * However we can safely take this lock because its the child
3833 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3836 * We have to re-check the event->owner field, if it is cleared
3837 * we raced with perf_event_exit_task(), acquiring the mutex
3838 * ensured they're done, and we can proceed with freeing the
3842 list_del_init(&event->owner_entry);
3843 mutex_unlock(&owner->perf_event_mutex);
3844 put_task_struct(owner);
3848 static void put_event(struct perf_event *event)
3850 struct perf_event_context *ctx;
3852 if (!atomic_long_dec_and_test(&event->refcount))
3855 if (!is_kernel_event(event))
3856 perf_remove_from_owner(event);
3859 * There are two ways this annotation is useful:
3861 * 1) there is a lock recursion from perf_event_exit_task
3862 * see the comment there.
3864 * 2) there is a lock-inversion with mmap_sem through
3865 * perf_read_group(), which takes faults while
3866 * holding ctx->mutex, however this is called after
3867 * the last filedesc died, so there is no possibility
3868 * to trigger the AB-BA case.
3870 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3871 WARN_ON_ONCE(ctx->parent_ctx);
3872 perf_remove_from_context(event, true);
3873 perf_event_ctx_unlock(event, ctx);
3878 int perf_event_release_kernel(struct perf_event *event)
3883 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3886 * Called when the last reference to the file is gone.
3888 static int perf_release(struct inode *inode, struct file *file)
3890 put_event(file->private_data);
3895 * Remove all orphanes events from the context.
3897 static void orphans_remove_work(struct work_struct *work)
3899 struct perf_event_context *ctx;
3900 struct perf_event *event, *tmp;
3902 ctx = container_of(work, struct perf_event_context,
3903 orphans_remove.work);
3905 mutex_lock(&ctx->mutex);
3906 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3907 struct perf_event *parent_event = event->parent;
3909 if (!is_orphaned_child(event))
3912 perf_remove_from_context(event, true);
3914 mutex_lock(&parent_event->child_mutex);
3915 list_del_init(&event->child_list);
3916 mutex_unlock(&parent_event->child_mutex);
3919 put_event(parent_event);
3922 raw_spin_lock_irq(&ctx->lock);
3923 ctx->orphans_remove_sched = false;
3924 raw_spin_unlock_irq(&ctx->lock);
3925 mutex_unlock(&ctx->mutex);
3930 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3932 struct perf_event *child;
3938 mutex_lock(&event->child_mutex);
3940 (void)perf_event_read(event, false);
3941 total += perf_event_count(event);
3943 *enabled += event->total_time_enabled +
3944 atomic64_read(&event->child_total_time_enabled);
3945 *running += event->total_time_running +
3946 atomic64_read(&event->child_total_time_running);
3948 list_for_each_entry(child, &event->child_list, child_list) {
3949 (void)perf_event_read(child, false);
3950 total += perf_event_count(child);
3951 *enabled += child->total_time_enabled;
3952 *running += child->total_time_running;
3954 mutex_unlock(&event->child_mutex);
3958 EXPORT_SYMBOL_GPL(perf_event_read_value);
3960 static int __perf_read_group_add(struct perf_event *leader,
3961 u64 read_format, u64 *values)
3963 struct perf_event *sub;
3964 int n = 1; /* skip @nr */
3967 ret = perf_event_read(leader, true);
3972 * Since we co-schedule groups, {enabled,running} times of siblings
3973 * will be identical to those of the leader, so we only publish one
3976 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3977 values[n++] += leader->total_time_enabled +
3978 atomic64_read(&leader->child_total_time_enabled);
3981 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3982 values[n++] += leader->total_time_running +
3983 atomic64_read(&leader->child_total_time_running);
3987 * Write {count,id} tuples for every sibling.
3989 values[n++] += perf_event_count(leader);
3990 if (read_format & PERF_FORMAT_ID)
3991 values[n++] = primary_event_id(leader);
3993 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3994 values[n++] += perf_event_count(sub);
3995 if (read_format & PERF_FORMAT_ID)
3996 values[n++] = primary_event_id(sub);
4002 static int perf_read_group(struct perf_event *event,
4003 u64 read_format, char __user *buf)
4005 struct perf_event *leader = event->group_leader, *child;
4006 struct perf_event_context *ctx = leader->ctx;
4010 lockdep_assert_held(&ctx->mutex);
4012 values = kzalloc(event->read_size, GFP_KERNEL);
4016 values[0] = 1 + leader->nr_siblings;
4019 * By locking the child_mutex of the leader we effectively
4020 * lock the child list of all siblings.. XXX explain how.
4022 mutex_lock(&leader->child_mutex);
4024 ret = __perf_read_group_add(leader, read_format, values);
4028 list_for_each_entry(child, &leader->child_list, child_list) {
4029 ret = __perf_read_group_add(child, read_format, values);
4034 mutex_unlock(&leader->child_mutex);
4036 ret = event->read_size;
4037 if (copy_to_user(buf, values, event->read_size))
4042 mutex_unlock(&leader->child_mutex);
4048 static int perf_read_one(struct perf_event *event,
4049 u64 read_format, char __user *buf)
4051 u64 enabled, running;
4055 values[n++] = perf_event_read_value(event, &enabled, &running);
4056 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4057 values[n++] = enabled;
4058 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4059 values[n++] = running;
4060 if (read_format & PERF_FORMAT_ID)
4061 values[n++] = primary_event_id(event);
4063 if (copy_to_user(buf, values, n * sizeof(u64)))
4066 return n * sizeof(u64);
4069 static bool is_event_hup(struct perf_event *event)
4073 if (event->state != PERF_EVENT_STATE_EXIT)
4076 mutex_lock(&event->child_mutex);
4077 no_children = list_empty(&event->child_list);
4078 mutex_unlock(&event->child_mutex);
4083 * Read the performance event - simple non blocking version for now
4086 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4088 u64 read_format = event->attr.read_format;
4092 * Return end-of-file for a read on a event that is in
4093 * error state (i.e. because it was pinned but it couldn't be
4094 * scheduled on to the CPU at some point).
4096 if (event->state == PERF_EVENT_STATE_ERROR)
4099 if (count < event->read_size)
4102 WARN_ON_ONCE(event->ctx->parent_ctx);
4103 if (read_format & PERF_FORMAT_GROUP)
4104 ret = perf_read_group(event, read_format, buf);
4106 ret = perf_read_one(event, read_format, buf);
4112 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4114 struct perf_event *event = file->private_data;
4115 struct perf_event_context *ctx;
4118 ctx = perf_event_ctx_lock(event);
4119 ret = __perf_read(event, buf, count);
4120 perf_event_ctx_unlock(event, ctx);
4125 static unsigned int perf_poll(struct file *file, poll_table *wait)
4127 struct perf_event *event = file->private_data;
4128 struct ring_buffer *rb;
4129 unsigned int events = POLLHUP;
4131 poll_wait(file, &event->waitq, wait);
4133 if (is_event_hup(event))
4137 * Pin the event->rb by taking event->mmap_mutex; otherwise
4138 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4140 mutex_lock(&event->mmap_mutex);
4143 events = atomic_xchg(&rb->poll, 0);
4144 mutex_unlock(&event->mmap_mutex);
4148 static void _perf_event_reset(struct perf_event *event)
4150 (void)perf_event_read(event, false);
4151 local64_set(&event->count, 0);
4152 perf_event_update_userpage(event);
4156 * Holding the top-level event's child_mutex means that any
4157 * descendant process that has inherited this event will block
4158 * in sync_child_event if it goes to exit, thus satisfying the
4159 * task existence requirements of perf_event_enable/disable.
4161 static void perf_event_for_each_child(struct perf_event *event,
4162 void (*func)(struct perf_event *))
4164 struct perf_event *child;
4166 WARN_ON_ONCE(event->ctx->parent_ctx);
4168 mutex_lock(&event->child_mutex);
4170 list_for_each_entry(child, &event->child_list, child_list)
4172 mutex_unlock(&event->child_mutex);
4175 static void perf_event_for_each(struct perf_event *event,
4176 void (*func)(struct perf_event *))
4178 struct perf_event_context *ctx = event->ctx;
4179 struct perf_event *sibling;
4181 lockdep_assert_held(&ctx->mutex);
4183 event = event->group_leader;
4185 perf_event_for_each_child(event, func);
4186 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4187 perf_event_for_each_child(sibling, func);
4190 struct period_event {
4191 struct perf_event *event;
4195 static int __perf_event_period(void *info)
4197 struct period_event *pe = info;
4198 struct perf_event *event = pe->event;
4199 struct perf_event_context *ctx = event->ctx;
4200 u64 value = pe->value;
4203 raw_spin_lock(&ctx->lock);
4204 if (event->attr.freq) {
4205 event->attr.sample_freq = value;
4207 event->attr.sample_period = value;
4208 event->hw.sample_period = value;
4211 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4213 perf_pmu_disable(ctx->pmu);
4214 event->pmu->stop(event, PERF_EF_UPDATE);
4217 local64_set(&event->hw.period_left, 0);
4220 event->pmu->start(event, PERF_EF_RELOAD);
4221 perf_pmu_enable(ctx->pmu);
4223 raw_spin_unlock(&ctx->lock);
4228 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4230 struct period_event pe = { .event = event, };
4231 struct perf_event_context *ctx = event->ctx;
4232 struct task_struct *task;
4235 if (!is_sampling_event(event))
4238 if (copy_from_user(&value, arg, sizeof(value)))
4244 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4251 cpu_function_call(event->cpu, __perf_event_period, &pe);
4256 if (!task_function_call(task, __perf_event_period, &pe))
4259 raw_spin_lock_irq(&ctx->lock);
4260 if (ctx->is_active) {
4261 raw_spin_unlock_irq(&ctx->lock);
4266 if (event->attr.freq) {
4267 event->attr.sample_freq = value;
4269 event->attr.sample_period = value;
4270 event->hw.sample_period = value;
4273 local64_set(&event->hw.period_left, 0);
4274 raw_spin_unlock_irq(&ctx->lock);
4279 static const struct file_operations perf_fops;
4281 static inline int perf_fget_light(int fd, struct fd *p)
4283 struct fd f = fdget(fd);
4287 if (f.file->f_op != &perf_fops) {
4295 static int perf_event_set_output(struct perf_event *event,
4296 struct perf_event *output_event);
4297 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4298 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4299 static int perf_event_drv_configs(struct perf_event *event,
4302 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4304 void (*func)(struct perf_event *);
4308 case PERF_EVENT_IOC_ENABLE:
4309 func = _perf_event_enable;
4311 case PERF_EVENT_IOC_DISABLE:
4312 func = _perf_event_disable;
4314 case PERF_EVENT_IOC_RESET:
4315 func = _perf_event_reset;
4318 case PERF_EVENT_IOC_REFRESH:
4319 return _perf_event_refresh(event, arg);
4321 case PERF_EVENT_IOC_PERIOD:
4322 return perf_event_period(event, (u64 __user *)arg);
4324 case PERF_EVENT_IOC_ID:
4326 u64 id = primary_event_id(event);
4328 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4333 case PERF_EVENT_IOC_SET_OUTPUT:
4337 struct perf_event *output_event;
4339 ret = perf_fget_light(arg, &output);
4342 output_event = output.file->private_data;
4343 ret = perf_event_set_output(event, output_event);
4346 ret = perf_event_set_output(event, NULL);
4351 case PERF_EVENT_IOC_SET_FILTER:
4352 return perf_event_set_filter(event, (void __user *)arg);
4354 case PERF_EVENT_IOC_SET_BPF:
4355 return perf_event_set_bpf_prog(event, arg);
4357 case PERF_EVENT_IOC_SET_DRV_CONFIGS:
4358 return perf_event_drv_configs(event, (void __user *)arg);
4364 if (flags & PERF_IOC_FLAG_GROUP)
4365 perf_event_for_each(event, func);
4367 perf_event_for_each_child(event, func);
4372 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4374 struct perf_event *event = file->private_data;
4375 struct perf_event_context *ctx;
4378 ctx = perf_event_ctx_lock(event);
4379 ret = _perf_ioctl(event, cmd, arg);
4380 perf_event_ctx_unlock(event, ctx);
4385 #ifdef CONFIG_COMPAT
4386 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4389 switch (_IOC_NR(cmd)) {
4390 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4391 case _IOC_NR(PERF_EVENT_IOC_ID):
4392 case _IOC_NR(PERF_EVENT_IOC_SET_DRV_CONFIGS):
4393 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4394 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4395 cmd &= ~IOCSIZE_MASK;
4396 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4400 return perf_ioctl(file, cmd, arg);
4403 # define perf_compat_ioctl NULL
4406 int perf_event_task_enable(void)
4408 struct perf_event_context *ctx;
4409 struct perf_event *event;
4411 mutex_lock(¤t->perf_event_mutex);
4412 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4413 ctx = perf_event_ctx_lock(event);
4414 perf_event_for_each_child(event, _perf_event_enable);
4415 perf_event_ctx_unlock(event, ctx);
4417 mutex_unlock(¤t->perf_event_mutex);
4422 int perf_event_task_disable(void)
4424 struct perf_event_context *ctx;
4425 struct perf_event *event;
4427 mutex_lock(¤t->perf_event_mutex);
4428 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4429 ctx = perf_event_ctx_lock(event);
4430 perf_event_for_each_child(event, _perf_event_disable);
4431 perf_event_ctx_unlock(event, ctx);
4433 mutex_unlock(¤t->perf_event_mutex);
4438 static int perf_event_index(struct perf_event *event)
4440 if (event->hw.state & PERF_HES_STOPPED)
4443 if (event->state != PERF_EVENT_STATE_ACTIVE)
4446 return event->pmu->event_idx(event);
4449 static void calc_timer_values(struct perf_event *event,
4456 *now = perf_clock();
4457 ctx_time = event->shadow_ctx_time + *now;
4458 *enabled = ctx_time - event->tstamp_enabled;
4459 *running = ctx_time - event->tstamp_running;
4462 static void perf_event_init_userpage(struct perf_event *event)
4464 struct perf_event_mmap_page *userpg;
4465 struct ring_buffer *rb;
4468 rb = rcu_dereference(event->rb);
4472 userpg = rb->user_page;
4474 /* Allow new userspace to detect that bit 0 is deprecated */
4475 userpg->cap_bit0_is_deprecated = 1;
4476 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4477 userpg->data_offset = PAGE_SIZE;
4478 userpg->data_size = perf_data_size(rb);
4484 void __weak arch_perf_update_userpage(
4485 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4490 * Callers need to ensure there can be no nesting of this function, otherwise
4491 * the seqlock logic goes bad. We can not serialize this because the arch
4492 * code calls this from NMI context.
4494 void perf_event_update_userpage(struct perf_event *event)
4496 struct perf_event_mmap_page *userpg;
4497 struct ring_buffer *rb;
4498 u64 enabled, running, now;
4501 rb = rcu_dereference(event->rb);
4506 * compute total_time_enabled, total_time_running
4507 * based on snapshot values taken when the event
4508 * was last scheduled in.
4510 * we cannot simply called update_context_time()
4511 * because of locking issue as we can be called in
4514 calc_timer_values(event, &now, &enabled, &running);
4516 userpg = rb->user_page;
4518 * Disable preemption so as to not let the corresponding user-space
4519 * spin too long if we get preempted.
4524 userpg->index = perf_event_index(event);
4525 userpg->offset = perf_event_count(event);
4527 userpg->offset -= local64_read(&event->hw.prev_count);
4529 userpg->time_enabled = enabled +
4530 atomic64_read(&event->child_total_time_enabled);
4532 userpg->time_running = running +
4533 atomic64_read(&event->child_total_time_running);
4535 arch_perf_update_userpage(event, userpg, now);
4544 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4546 struct perf_event *event = vma->vm_file->private_data;
4547 struct ring_buffer *rb;
4548 int ret = VM_FAULT_SIGBUS;
4550 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4551 if (vmf->pgoff == 0)
4557 rb = rcu_dereference(event->rb);
4561 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4564 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4568 get_page(vmf->page);
4569 vmf->page->mapping = vma->vm_file->f_mapping;
4570 vmf->page->index = vmf->pgoff;
4579 static void ring_buffer_attach(struct perf_event *event,
4580 struct ring_buffer *rb)
4582 struct ring_buffer *old_rb = NULL;
4583 unsigned long flags;
4587 * Should be impossible, we set this when removing
4588 * event->rb_entry and wait/clear when adding event->rb_entry.
4590 WARN_ON_ONCE(event->rcu_pending);
4593 spin_lock_irqsave(&old_rb->event_lock, flags);
4594 list_del_rcu(&event->rb_entry);
4595 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4597 event->rcu_batches = get_state_synchronize_rcu();
4598 event->rcu_pending = 1;
4602 if (event->rcu_pending) {
4603 cond_synchronize_rcu(event->rcu_batches);
4604 event->rcu_pending = 0;
4607 spin_lock_irqsave(&rb->event_lock, flags);
4608 list_add_rcu(&event->rb_entry, &rb->event_list);
4609 spin_unlock_irqrestore(&rb->event_lock, flags);
4612 rcu_assign_pointer(event->rb, rb);
4615 ring_buffer_put(old_rb);
4617 * Since we detached before setting the new rb, so that we
4618 * could attach the new rb, we could have missed a wakeup.
4621 wake_up_all(&event->waitq);
4625 static void ring_buffer_wakeup(struct perf_event *event)
4627 struct ring_buffer *rb;
4630 rb = rcu_dereference(event->rb);
4632 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4633 wake_up_all(&event->waitq);
4638 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4640 struct ring_buffer *rb;
4643 rb = rcu_dereference(event->rb);
4645 if (!atomic_inc_not_zero(&rb->refcount))
4653 void ring_buffer_put(struct ring_buffer *rb)
4655 if (!atomic_dec_and_test(&rb->refcount))
4658 WARN_ON_ONCE(!list_empty(&rb->event_list));
4660 call_rcu(&rb->rcu_head, rb_free_rcu);
4663 static void perf_mmap_open(struct vm_area_struct *vma)
4665 struct perf_event *event = vma->vm_file->private_data;
4667 atomic_inc(&event->mmap_count);
4668 atomic_inc(&event->rb->mmap_count);
4671 atomic_inc(&event->rb->aux_mmap_count);
4673 if (event->pmu->event_mapped)
4674 event->pmu->event_mapped(event);
4677 static void perf_pmu_output_stop(struct perf_event *event);
4680 * A buffer can be mmap()ed multiple times; either directly through the same
4681 * event, or through other events by use of perf_event_set_output().
4683 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4684 * the buffer here, where we still have a VM context. This means we need
4685 * to detach all events redirecting to us.
4687 static void perf_mmap_close(struct vm_area_struct *vma)
4689 struct perf_event *event = vma->vm_file->private_data;
4691 struct ring_buffer *rb = ring_buffer_get(event);
4692 struct user_struct *mmap_user = rb->mmap_user;
4693 int mmap_locked = rb->mmap_locked;
4694 unsigned long size = perf_data_size(rb);
4696 if (event->pmu->event_unmapped)
4697 event->pmu->event_unmapped(event);
4700 * rb->aux_mmap_count will always drop before rb->mmap_count and
4701 * event->mmap_count, so it is ok to use event->mmap_mutex to
4702 * serialize with perf_mmap here.
4704 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4705 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4707 * Stop all AUX events that are writing to this buffer,
4708 * so that we can free its AUX pages and corresponding PMU
4709 * data. Note that after rb::aux_mmap_count dropped to zero,
4710 * they won't start any more (see perf_aux_output_begin()).
4712 perf_pmu_output_stop(event);
4714 /* now it's safe to free the pages */
4715 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4716 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4718 /* this has to be the last one */
4720 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4722 mutex_unlock(&event->mmap_mutex);
4725 atomic_dec(&rb->mmap_count);
4727 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4730 ring_buffer_attach(event, NULL);
4731 mutex_unlock(&event->mmap_mutex);
4733 /* If there's still other mmap()s of this buffer, we're done. */
4734 if (atomic_read(&rb->mmap_count))
4738 * No other mmap()s, detach from all other events that might redirect
4739 * into the now unreachable buffer. Somewhat complicated by the
4740 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4744 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4745 if (!atomic_long_inc_not_zero(&event->refcount)) {
4747 * This event is en-route to free_event() which will
4748 * detach it and remove it from the list.
4754 mutex_lock(&event->mmap_mutex);
4756 * Check we didn't race with perf_event_set_output() which can
4757 * swizzle the rb from under us while we were waiting to
4758 * acquire mmap_mutex.
4760 * If we find a different rb; ignore this event, a next
4761 * iteration will no longer find it on the list. We have to
4762 * still restart the iteration to make sure we're not now
4763 * iterating the wrong list.
4765 if (event->rb == rb)
4766 ring_buffer_attach(event, NULL);
4768 mutex_unlock(&event->mmap_mutex);
4772 * Restart the iteration; either we're on the wrong list or
4773 * destroyed its integrity by doing a deletion.
4780 * It could be there's still a few 0-ref events on the list; they'll
4781 * get cleaned up by free_event() -- they'll also still have their
4782 * ref on the rb and will free it whenever they are done with it.
4784 * Aside from that, this buffer is 'fully' detached and unmapped,
4785 * undo the VM accounting.
4788 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4789 vma->vm_mm->pinned_vm -= mmap_locked;
4790 free_uid(mmap_user);
4793 ring_buffer_put(rb); /* could be last */
4796 static const struct vm_operations_struct perf_mmap_vmops = {
4797 .open = perf_mmap_open,
4798 .close = perf_mmap_close, /* non mergable */
4799 .fault = perf_mmap_fault,
4800 .page_mkwrite = perf_mmap_fault,
4803 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4805 struct perf_event *event = file->private_data;
4806 unsigned long user_locked, user_lock_limit;
4807 struct user_struct *user = current_user();
4808 unsigned long locked, lock_limit;
4809 struct ring_buffer *rb = NULL;
4810 unsigned long vma_size;
4811 unsigned long nr_pages;
4812 long user_extra = 0, extra = 0;
4813 int ret = 0, flags = 0;
4816 * Don't allow mmap() of inherited per-task counters. This would
4817 * create a performance issue due to all children writing to the
4820 if (event->cpu == -1 && event->attr.inherit)
4823 if (!(vma->vm_flags & VM_SHARED))
4826 vma_size = vma->vm_end - vma->vm_start;
4828 if (vma->vm_pgoff == 0) {
4829 nr_pages = (vma_size / PAGE_SIZE) - 1;
4832 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4833 * mapped, all subsequent mappings should have the same size
4834 * and offset. Must be above the normal perf buffer.
4836 u64 aux_offset, aux_size;
4841 nr_pages = vma_size / PAGE_SIZE;
4843 mutex_lock(&event->mmap_mutex);
4850 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4851 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4853 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4856 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4859 /* already mapped with a different offset */
4860 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4863 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4866 /* already mapped with a different size */
4867 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4870 if (!is_power_of_2(nr_pages))
4873 if (!atomic_inc_not_zero(&rb->mmap_count))
4876 if (rb_has_aux(rb)) {
4877 atomic_inc(&rb->aux_mmap_count);
4882 atomic_set(&rb->aux_mmap_count, 1);
4883 user_extra = nr_pages;
4889 * If we have rb pages ensure they're a power-of-two number, so we
4890 * can do bitmasks instead of modulo.
4892 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4895 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4898 WARN_ON_ONCE(event->ctx->parent_ctx);
4900 mutex_lock(&event->mmap_mutex);
4902 if (event->rb->nr_pages != nr_pages) {
4907 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4909 * Raced against perf_mmap_close() through
4910 * perf_event_set_output(). Try again, hope for better
4913 mutex_unlock(&event->mmap_mutex);
4920 user_extra = nr_pages + 1;
4923 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4926 * Increase the limit linearly with more CPUs:
4928 user_lock_limit *= num_online_cpus();
4930 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4932 if (user_locked > user_lock_limit)
4933 extra = user_locked - user_lock_limit;
4935 lock_limit = rlimit(RLIMIT_MEMLOCK);
4936 lock_limit >>= PAGE_SHIFT;
4937 locked = vma->vm_mm->pinned_vm + extra;
4939 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4940 !capable(CAP_IPC_LOCK)) {
4945 WARN_ON(!rb && event->rb);
4947 if (vma->vm_flags & VM_WRITE)
4948 flags |= RING_BUFFER_WRITABLE;
4951 rb = rb_alloc(nr_pages,
4952 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4960 atomic_set(&rb->mmap_count, 1);
4961 rb->mmap_user = get_current_user();
4962 rb->mmap_locked = extra;
4964 ring_buffer_attach(event, rb);
4966 perf_event_init_userpage(event);
4967 perf_event_update_userpage(event);
4969 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4970 event->attr.aux_watermark, flags);
4972 rb->aux_mmap_locked = extra;
4977 atomic_long_add(user_extra, &user->locked_vm);
4978 vma->vm_mm->pinned_vm += extra;
4980 atomic_inc(&event->mmap_count);
4982 atomic_dec(&rb->mmap_count);
4985 mutex_unlock(&event->mmap_mutex);
4988 * Since pinned accounting is per vm we cannot allow fork() to copy our
4991 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4992 vma->vm_ops = &perf_mmap_vmops;
4994 if (event->pmu->event_mapped)
4995 event->pmu->event_mapped(event);
5000 static int perf_fasync(int fd, struct file *filp, int on)
5002 struct inode *inode = file_inode(filp);
5003 struct perf_event *event = filp->private_data;
5006 mutex_lock(&inode->i_mutex);
5007 retval = fasync_helper(fd, filp, on, &event->fasync);
5008 mutex_unlock(&inode->i_mutex);
5016 static const struct file_operations perf_fops = {
5017 .llseek = no_llseek,
5018 .release = perf_release,
5021 .unlocked_ioctl = perf_ioctl,
5022 .compat_ioctl = perf_compat_ioctl,
5024 .fasync = perf_fasync,
5030 * If there's data, ensure we set the poll() state and publish everything
5031 * to user-space before waking everybody up.
5034 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5036 /* only the parent has fasync state */
5038 event = event->parent;
5039 return &event->fasync;
5042 void perf_event_wakeup(struct perf_event *event)
5044 ring_buffer_wakeup(event);
5046 if (event->pending_kill) {
5047 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5048 event->pending_kill = 0;
5052 static void perf_pending_event(struct irq_work *entry)
5054 struct perf_event *event = container_of(entry,
5055 struct perf_event, pending);
5058 rctx = perf_swevent_get_recursion_context();
5060 * If we 'fail' here, that's OK, it means recursion is already disabled
5061 * and we won't recurse 'further'.
5064 if (event->pending_disable) {
5065 event->pending_disable = 0;
5066 __perf_event_disable(event);
5069 if (event->pending_wakeup) {
5070 event->pending_wakeup = 0;
5071 perf_event_wakeup(event);
5075 perf_swevent_put_recursion_context(rctx);
5079 * We assume there is only KVM supporting the callbacks.
5080 * Later on, we might change it to a list if there is
5081 * another virtualization implementation supporting the callbacks.
5083 struct perf_guest_info_callbacks *perf_guest_cbs;
5085 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5087 perf_guest_cbs = cbs;
5090 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5092 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5094 perf_guest_cbs = NULL;
5097 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5100 perf_output_sample_regs(struct perf_output_handle *handle,
5101 struct pt_regs *regs, u64 mask)
5105 for_each_set_bit(bit, (const unsigned long *) &mask,
5106 sizeof(mask) * BITS_PER_BYTE) {
5109 val = perf_reg_value(regs, bit);
5110 perf_output_put(handle, val);
5114 static void perf_sample_regs_user(struct perf_regs *regs_user,
5115 struct pt_regs *regs,
5116 struct pt_regs *regs_user_copy)
5118 if (user_mode(regs)) {
5119 regs_user->abi = perf_reg_abi(current);
5120 regs_user->regs = regs;
5121 } else if (current->mm) {
5122 perf_get_regs_user(regs_user, regs, regs_user_copy);
5124 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5125 regs_user->regs = NULL;
5129 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5130 struct pt_regs *regs)
5132 regs_intr->regs = regs;
5133 regs_intr->abi = perf_reg_abi(current);
5138 * Get remaining task size from user stack pointer.
5140 * It'd be better to take stack vma map and limit this more
5141 * precisly, but there's no way to get it safely under interrupt,
5142 * so using TASK_SIZE as limit.
5144 static u64 perf_ustack_task_size(struct pt_regs *regs)
5146 unsigned long addr = perf_user_stack_pointer(regs);
5148 if (!addr || addr >= TASK_SIZE)
5151 return TASK_SIZE - addr;
5155 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5156 struct pt_regs *regs)
5160 /* No regs, no stack pointer, no dump. */
5165 * Check if we fit in with the requested stack size into the:
5167 * If we don't, we limit the size to the TASK_SIZE.
5169 * - remaining sample size
5170 * If we don't, we customize the stack size to
5171 * fit in to the remaining sample size.
5174 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5175 stack_size = min(stack_size, (u16) task_size);
5177 /* Current header size plus static size and dynamic size. */
5178 header_size += 2 * sizeof(u64);
5180 /* Do we fit in with the current stack dump size? */
5181 if ((u16) (header_size + stack_size) < header_size) {
5183 * If we overflow the maximum size for the sample,
5184 * we customize the stack dump size to fit in.
5186 stack_size = USHRT_MAX - header_size - sizeof(u64);
5187 stack_size = round_up(stack_size, sizeof(u64));
5194 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5195 struct pt_regs *regs)
5197 /* Case of a kernel thread, nothing to dump */
5200 perf_output_put(handle, size);
5209 * - the size requested by user or the best one we can fit
5210 * in to the sample max size
5212 * - user stack dump data
5214 * - the actual dumped size
5218 perf_output_put(handle, dump_size);
5221 sp = perf_user_stack_pointer(regs);
5222 rem = __output_copy_user(handle, (void *) sp, dump_size);
5223 dyn_size = dump_size - rem;
5225 perf_output_skip(handle, rem);
5228 perf_output_put(handle, dyn_size);
5232 static void __perf_event_header__init_id(struct perf_event_header *header,
5233 struct perf_sample_data *data,
5234 struct perf_event *event)
5236 u64 sample_type = event->attr.sample_type;
5238 data->type = sample_type;
5239 header->size += event->id_header_size;
5241 if (sample_type & PERF_SAMPLE_TID) {
5242 /* namespace issues */
5243 data->tid_entry.pid = perf_event_pid(event, current);
5244 data->tid_entry.tid = perf_event_tid(event, current);
5247 if (sample_type & PERF_SAMPLE_TIME)
5248 data->time = perf_event_clock(event);
5250 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5251 data->id = primary_event_id(event);
5253 if (sample_type & PERF_SAMPLE_STREAM_ID)
5254 data->stream_id = event->id;
5256 if (sample_type & PERF_SAMPLE_CPU) {
5257 data->cpu_entry.cpu = raw_smp_processor_id();
5258 data->cpu_entry.reserved = 0;
5262 void perf_event_header__init_id(struct perf_event_header *header,
5263 struct perf_sample_data *data,
5264 struct perf_event *event)
5266 if (event->attr.sample_id_all)
5267 __perf_event_header__init_id(header, data, event);
5270 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5271 struct perf_sample_data *data)
5273 u64 sample_type = data->type;
5275 if (sample_type & PERF_SAMPLE_TID)
5276 perf_output_put(handle, data->tid_entry);
5278 if (sample_type & PERF_SAMPLE_TIME)
5279 perf_output_put(handle, data->time);
5281 if (sample_type & PERF_SAMPLE_ID)
5282 perf_output_put(handle, data->id);
5284 if (sample_type & PERF_SAMPLE_STREAM_ID)
5285 perf_output_put(handle, data->stream_id);
5287 if (sample_type & PERF_SAMPLE_CPU)
5288 perf_output_put(handle, data->cpu_entry);
5290 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5291 perf_output_put(handle, data->id);
5294 void perf_event__output_id_sample(struct perf_event *event,
5295 struct perf_output_handle *handle,
5296 struct perf_sample_data *sample)
5298 if (event->attr.sample_id_all)
5299 __perf_event__output_id_sample(handle, sample);
5302 static void perf_output_read_one(struct perf_output_handle *handle,
5303 struct perf_event *event,
5304 u64 enabled, u64 running)
5306 u64 read_format = event->attr.read_format;
5310 values[n++] = perf_event_count(event);
5311 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5312 values[n++] = enabled +
5313 atomic64_read(&event->child_total_time_enabled);
5315 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5316 values[n++] = running +
5317 atomic64_read(&event->child_total_time_running);
5319 if (read_format & PERF_FORMAT_ID)
5320 values[n++] = primary_event_id(event);
5322 __output_copy(handle, values, n * sizeof(u64));
5326 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5328 static void perf_output_read_group(struct perf_output_handle *handle,
5329 struct perf_event *event,
5330 u64 enabled, u64 running)
5332 struct perf_event *leader = event->group_leader, *sub;
5333 u64 read_format = event->attr.read_format;
5337 values[n++] = 1 + leader->nr_siblings;
5339 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5340 values[n++] = enabled;
5342 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5343 values[n++] = running;
5345 if (leader != event)
5346 leader->pmu->read(leader);
5348 values[n++] = perf_event_count(leader);
5349 if (read_format & PERF_FORMAT_ID)
5350 values[n++] = primary_event_id(leader);
5352 __output_copy(handle, values, n * sizeof(u64));
5354 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5357 if ((sub != event) &&
5358 (sub->state == PERF_EVENT_STATE_ACTIVE))
5359 sub->pmu->read(sub);
5361 values[n++] = perf_event_count(sub);
5362 if (read_format & PERF_FORMAT_ID)
5363 values[n++] = primary_event_id(sub);
5365 __output_copy(handle, values, n * sizeof(u64));
5369 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5370 PERF_FORMAT_TOTAL_TIME_RUNNING)
5372 static void perf_output_read(struct perf_output_handle *handle,
5373 struct perf_event *event)
5375 u64 enabled = 0, running = 0, now;
5376 u64 read_format = event->attr.read_format;
5379 * compute total_time_enabled, total_time_running
5380 * based on snapshot values taken when the event
5381 * was last scheduled in.
5383 * we cannot simply called update_context_time()
5384 * because of locking issue as we are called in
5387 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5388 calc_timer_values(event, &now, &enabled, &running);
5390 if (event->attr.read_format & PERF_FORMAT_GROUP)
5391 perf_output_read_group(handle, event, enabled, running);
5393 perf_output_read_one(handle, event, enabled, running);
5396 void perf_output_sample(struct perf_output_handle *handle,
5397 struct perf_event_header *header,
5398 struct perf_sample_data *data,
5399 struct perf_event *event)
5401 u64 sample_type = data->type;
5403 perf_output_put(handle, *header);
5405 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5406 perf_output_put(handle, data->id);
5408 if (sample_type & PERF_SAMPLE_IP)
5409 perf_output_put(handle, data->ip);
5411 if (sample_type & PERF_SAMPLE_TID)
5412 perf_output_put(handle, data->tid_entry);
5414 if (sample_type & PERF_SAMPLE_TIME)
5415 perf_output_put(handle, data->time);
5417 if (sample_type & PERF_SAMPLE_ADDR)
5418 perf_output_put(handle, data->addr);
5420 if (sample_type & PERF_SAMPLE_ID)
5421 perf_output_put(handle, data->id);
5423 if (sample_type & PERF_SAMPLE_STREAM_ID)
5424 perf_output_put(handle, data->stream_id);
5426 if (sample_type & PERF_SAMPLE_CPU)
5427 perf_output_put(handle, data->cpu_entry);
5429 if (sample_type & PERF_SAMPLE_PERIOD)
5430 perf_output_put(handle, data->period);
5432 if (sample_type & PERF_SAMPLE_READ)
5433 perf_output_read(handle, event);
5435 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5436 if (data->callchain) {
5439 if (data->callchain)
5440 size += data->callchain->nr;
5442 size *= sizeof(u64);
5444 __output_copy(handle, data->callchain, size);
5447 perf_output_put(handle, nr);
5451 if (sample_type & PERF_SAMPLE_RAW) {
5453 u32 raw_size = data->raw->size;
5454 u32 real_size = round_up(raw_size + sizeof(u32),
5455 sizeof(u64)) - sizeof(u32);
5458 perf_output_put(handle, real_size);
5459 __output_copy(handle, data->raw->data, raw_size);
5460 if (real_size - raw_size)
5461 __output_copy(handle, &zero, real_size - raw_size);
5467 .size = sizeof(u32),
5470 perf_output_put(handle, raw);
5474 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5475 if (data->br_stack) {
5478 size = data->br_stack->nr
5479 * sizeof(struct perf_branch_entry);
5481 perf_output_put(handle, data->br_stack->nr);
5482 perf_output_copy(handle, data->br_stack->entries, size);
5485 * we always store at least the value of nr
5488 perf_output_put(handle, nr);
5492 if (sample_type & PERF_SAMPLE_REGS_USER) {
5493 u64 abi = data->regs_user.abi;
5496 * If there are no regs to dump, notice it through
5497 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5499 perf_output_put(handle, abi);
5502 u64 mask = event->attr.sample_regs_user;
5503 perf_output_sample_regs(handle,
5504 data->regs_user.regs,
5509 if (sample_type & PERF_SAMPLE_STACK_USER) {
5510 perf_output_sample_ustack(handle,
5511 data->stack_user_size,
5512 data->regs_user.regs);
5515 if (sample_type & PERF_SAMPLE_WEIGHT)
5516 perf_output_put(handle, data->weight);
5518 if (sample_type & PERF_SAMPLE_DATA_SRC)
5519 perf_output_put(handle, data->data_src.val);
5521 if (sample_type & PERF_SAMPLE_TRANSACTION)
5522 perf_output_put(handle, data->txn);
5524 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5525 u64 abi = data->regs_intr.abi;
5527 * If there are no regs to dump, notice it through
5528 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5530 perf_output_put(handle, abi);
5533 u64 mask = event->attr.sample_regs_intr;
5535 perf_output_sample_regs(handle,
5536 data->regs_intr.regs,
5541 if (!event->attr.watermark) {
5542 int wakeup_events = event->attr.wakeup_events;
5544 if (wakeup_events) {
5545 struct ring_buffer *rb = handle->rb;
5546 int events = local_inc_return(&rb->events);
5548 if (events >= wakeup_events) {
5549 local_sub(wakeup_events, &rb->events);
5550 local_inc(&rb->wakeup);
5556 void perf_prepare_sample(struct perf_event_header *header,
5557 struct perf_sample_data *data,
5558 struct perf_event *event,
5559 struct pt_regs *regs)
5561 u64 sample_type = event->attr.sample_type;
5563 header->type = PERF_RECORD_SAMPLE;
5564 header->size = sizeof(*header) + event->header_size;
5567 header->misc |= perf_misc_flags(regs);
5569 __perf_event_header__init_id(header, data, event);
5571 if (sample_type & PERF_SAMPLE_IP)
5572 data->ip = perf_instruction_pointer(regs);
5574 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5577 data->callchain = perf_callchain(event, regs);
5579 if (data->callchain)
5580 size += data->callchain->nr;
5582 header->size += size * sizeof(u64);
5585 if (sample_type & PERF_SAMPLE_RAW) {
5586 int size = sizeof(u32);
5589 size += data->raw->size;
5591 size += sizeof(u32);
5593 header->size += round_up(size, sizeof(u64));
5596 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5597 int size = sizeof(u64); /* nr */
5598 if (data->br_stack) {
5599 size += data->br_stack->nr
5600 * sizeof(struct perf_branch_entry);
5602 header->size += size;
5605 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5606 perf_sample_regs_user(&data->regs_user, regs,
5607 &data->regs_user_copy);
5609 if (sample_type & PERF_SAMPLE_REGS_USER) {
5610 /* regs dump ABI info */
5611 int size = sizeof(u64);
5613 if (data->regs_user.regs) {
5614 u64 mask = event->attr.sample_regs_user;
5615 size += hweight64(mask) * sizeof(u64);
5618 header->size += size;
5621 if (sample_type & PERF_SAMPLE_STACK_USER) {
5623 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5624 * processed as the last one or have additional check added
5625 * in case new sample type is added, because we could eat
5626 * up the rest of the sample size.
5628 u16 stack_size = event->attr.sample_stack_user;
5629 u16 size = sizeof(u64);
5631 stack_size = perf_sample_ustack_size(stack_size, header->size,
5632 data->regs_user.regs);
5635 * If there is something to dump, add space for the dump
5636 * itself and for the field that tells the dynamic size,
5637 * which is how many have been actually dumped.
5640 size += sizeof(u64) + stack_size;
5642 data->stack_user_size = stack_size;
5643 header->size += size;
5646 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5647 /* regs dump ABI info */
5648 int size = sizeof(u64);
5650 perf_sample_regs_intr(&data->regs_intr, regs);
5652 if (data->regs_intr.regs) {
5653 u64 mask = event->attr.sample_regs_intr;
5655 size += hweight64(mask) * sizeof(u64);
5658 header->size += size;
5662 void perf_event_output(struct perf_event *event,
5663 struct perf_sample_data *data,
5664 struct pt_regs *regs)
5666 struct perf_output_handle handle;
5667 struct perf_event_header header;
5669 /* protect the callchain buffers */
5672 perf_prepare_sample(&header, data, event, regs);
5674 if (perf_output_begin(&handle, event, header.size))
5677 perf_output_sample(&handle, &header, data, event);
5679 perf_output_end(&handle);
5689 struct perf_read_event {
5690 struct perf_event_header header;
5697 perf_event_read_event(struct perf_event *event,
5698 struct task_struct *task)
5700 struct perf_output_handle handle;
5701 struct perf_sample_data sample;
5702 struct perf_read_event read_event = {
5704 .type = PERF_RECORD_READ,
5706 .size = sizeof(read_event) + event->read_size,
5708 .pid = perf_event_pid(event, task),
5709 .tid = perf_event_tid(event, task),
5713 perf_event_header__init_id(&read_event.header, &sample, event);
5714 ret = perf_output_begin(&handle, event, read_event.header.size);
5718 perf_output_put(&handle, read_event);
5719 perf_output_read(&handle, event);
5720 perf_event__output_id_sample(event, &handle, &sample);
5722 perf_output_end(&handle);
5725 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5728 perf_event_aux_ctx(struct perf_event_context *ctx,
5729 perf_event_aux_output_cb output,
5732 struct perf_event *event;
5734 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5735 if (event->state < PERF_EVENT_STATE_INACTIVE)
5737 if (!event_filter_match(event))
5739 output(event, data);
5744 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5745 struct perf_event_context *task_ctx)
5749 perf_event_aux_ctx(task_ctx, output, data);
5755 perf_event_aux(perf_event_aux_output_cb output, void *data,
5756 struct perf_event_context *task_ctx)
5758 struct perf_cpu_context *cpuctx;
5759 struct perf_event_context *ctx;
5764 * If we have task_ctx != NULL we only notify
5765 * the task context itself. The task_ctx is set
5766 * only for EXIT events before releasing task
5770 perf_event_aux_task_ctx(output, data, task_ctx);
5775 list_for_each_entry_rcu(pmu, &pmus, entry) {
5776 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5777 if (cpuctx->unique_pmu != pmu)
5779 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5780 ctxn = pmu->task_ctx_nr;
5783 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5785 perf_event_aux_ctx(ctx, output, data);
5787 put_cpu_ptr(pmu->pmu_cpu_context);
5792 struct remote_output {
5793 struct ring_buffer *rb;
5797 static void __perf_event_output_stop(struct perf_event *event, void *data)
5799 struct perf_event *parent = event->parent;
5800 struct remote_output *ro = data;
5801 struct ring_buffer *rb = ro->rb;
5803 if (!has_aux(event))
5810 * In case of inheritance, it will be the parent that links to the
5811 * ring-buffer, but it will be the child that's actually using it:
5813 if (rcu_dereference(parent->rb) == rb)
5814 ro->err = __perf_event_stop(event);
5817 static int __perf_pmu_output_stop(void *info)
5819 struct perf_event *event = info;
5820 struct pmu *pmu = event->pmu;
5821 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5822 struct remote_output ro = {
5827 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro);
5828 if (cpuctx->task_ctx)
5829 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop,
5836 static void perf_pmu_output_stop(struct perf_event *event)
5838 struct perf_event *iter;
5843 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
5845 * For per-CPU events, we need to make sure that neither they
5846 * nor their children are running; for cpu==-1 events it's
5847 * sufficient to stop the event itself if it's active, since
5848 * it can't have children.
5852 cpu = READ_ONCE(iter->oncpu);
5857 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
5858 if (err == -EAGAIN) {
5867 * task tracking -- fork/exit
5869 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5872 struct perf_task_event {
5873 struct task_struct *task;
5874 struct perf_event_context *task_ctx;
5877 struct perf_event_header header;
5887 static int perf_event_task_match(struct perf_event *event)
5889 return event->attr.comm || event->attr.mmap ||
5890 event->attr.mmap2 || event->attr.mmap_data ||
5894 static void perf_event_task_output(struct perf_event *event,
5897 struct perf_task_event *task_event = data;
5898 struct perf_output_handle handle;
5899 struct perf_sample_data sample;
5900 struct task_struct *task = task_event->task;
5901 int ret, size = task_event->event_id.header.size;
5903 if (!perf_event_task_match(event))
5906 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5908 ret = perf_output_begin(&handle, event,
5909 task_event->event_id.header.size);
5913 task_event->event_id.pid = perf_event_pid(event, task);
5914 task_event->event_id.ppid = perf_event_pid(event, current);
5916 task_event->event_id.tid = perf_event_tid(event, task);
5917 task_event->event_id.ptid = perf_event_tid(event, current);
5919 task_event->event_id.time = perf_event_clock(event);
5921 perf_output_put(&handle, task_event->event_id);
5923 perf_event__output_id_sample(event, &handle, &sample);
5925 perf_output_end(&handle);
5927 task_event->event_id.header.size = size;
5930 static void perf_event_task(struct task_struct *task,
5931 struct perf_event_context *task_ctx,
5934 struct perf_task_event task_event;
5936 if (!atomic_read(&nr_comm_events) &&
5937 !atomic_read(&nr_mmap_events) &&
5938 !atomic_read(&nr_task_events))
5941 task_event = (struct perf_task_event){
5943 .task_ctx = task_ctx,
5946 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5948 .size = sizeof(task_event.event_id),
5958 perf_event_aux(perf_event_task_output,
5963 void perf_event_fork(struct task_struct *task)
5965 perf_event_task(task, NULL, 1);
5972 struct perf_comm_event {
5973 struct task_struct *task;
5978 struct perf_event_header header;
5985 static int perf_event_comm_match(struct perf_event *event)
5987 return event->attr.comm;
5990 static void perf_event_comm_output(struct perf_event *event,
5993 struct perf_comm_event *comm_event = data;
5994 struct perf_output_handle handle;
5995 struct perf_sample_data sample;
5996 int size = comm_event->event_id.header.size;
5999 if (!perf_event_comm_match(event))
6002 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6003 ret = perf_output_begin(&handle, event,
6004 comm_event->event_id.header.size);
6009 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6010 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6012 perf_output_put(&handle, comm_event->event_id);
6013 __output_copy(&handle, comm_event->comm,
6014 comm_event->comm_size);
6016 perf_event__output_id_sample(event, &handle, &sample);
6018 perf_output_end(&handle);
6020 comm_event->event_id.header.size = size;
6023 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6025 char comm[TASK_COMM_LEN];
6028 memset(comm, 0, sizeof(comm));
6029 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6030 size = ALIGN(strlen(comm)+1, sizeof(u64));
6032 comm_event->comm = comm;
6033 comm_event->comm_size = size;
6035 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6037 perf_event_aux(perf_event_comm_output,
6042 void perf_event_comm(struct task_struct *task, bool exec)
6044 struct perf_comm_event comm_event;
6046 if (!atomic_read(&nr_comm_events))
6049 comm_event = (struct perf_comm_event){
6055 .type = PERF_RECORD_COMM,
6056 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6064 perf_event_comm_event(&comm_event);
6071 struct perf_mmap_event {
6072 struct vm_area_struct *vma;
6074 const char *file_name;
6082 struct perf_event_header header;
6092 static int perf_event_mmap_match(struct perf_event *event,
6095 struct perf_mmap_event *mmap_event = data;
6096 struct vm_area_struct *vma = mmap_event->vma;
6097 int executable = vma->vm_flags & VM_EXEC;
6099 return (!executable && event->attr.mmap_data) ||
6100 (executable && (event->attr.mmap || event->attr.mmap2));
6103 static void perf_event_mmap_output(struct perf_event *event,
6106 struct perf_mmap_event *mmap_event = data;
6107 struct perf_output_handle handle;
6108 struct perf_sample_data sample;
6109 int size = mmap_event->event_id.header.size;
6112 if (!perf_event_mmap_match(event, data))
6115 if (event->attr.mmap2) {
6116 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6117 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6118 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6119 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6120 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6121 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6122 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6125 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6126 ret = perf_output_begin(&handle, event,
6127 mmap_event->event_id.header.size);
6131 mmap_event->event_id.pid = perf_event_pid(event, current);
6132 mmap_event->event_id.tid = perf_event_tid(event, current);
6134 perf_output_put(&handle, mmap_event->event_id);
6136 if (event->attr.mmap2) {
6137 perf_output_put(&handle, mmap_event->maj);
6138 perf_output_put(&handle, mmap_event->min);
6139 perf_output_put(&handle, mmap_event->ino);
6140 perf_output_put(&handle, mmap_event->ino_generation);
6141 perf_output_put(&handle, mmap_event->prot);
6142 perf_output_put(&handle, mmap_event->flags);
6145 __output_copy(&handle, mmap_event->file_name,
6146 mmap_event->file_size);
6148 perf_event__output_id_sample(event, &handle, &sample);
6150 perf_output_end(&handle);
6152 mmap_event->event_id.header.size = size;
6155 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6157 struct vm_area_struct *vma = mmap_event->vma;
6158 struct file *file = vma->vm_file;
6159 int maj = 0, min = 0;
6160 u64 ino = 0, gen = 0;
6161 u32 prot = 0, flags = 0;
6168 struct inode *inode;
6171 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6177 * d_path() works from the end of the rb backwards, so we
6178 * need to add enough zero bytes after the string to handle
6179 * the 64bit alignment we do later.
6181 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6186 inode = file_inode(vma->vm_file);
6187 dev = inode->i_sb->s_dev;
6189 gen = inode->i_generation;
6193 if (vma->vm_flags & VM_READ)
6195 if (vma->vm_flags & VM_WRITE)
6197 if (vma->vm_flags & VM_EXEC)
6200 if (vma->vm_flags & VM_MAYSHARE)
6203 flags = MAP_PRIVATE;
6205 if (vma->vm_flags & VM_DENYWRITE)
6206 flags |= MAP_DENYWRITE;
6207 if (vma->vm_flags & VM_MAYEXEC)
6208 flags |= MAP_EXECUTABLE;
6209 if (vma->vm_flags & VM_LOCKED)
6210 flags |= MAP_LOCKED;
6211 if (vma->vm_flags & VM_HUGETLB)
6212 flags |= MAP_HUGETLB;
6216 if (vma->vm_ops && vma->vm_ops->name) {
6217 name = (char *) vma->vm_ops->name(vma);
6222 name = (char *)arch_vma_name(vma);
6226 if (vma->vm_start <= vma->vm_mm->start_brk &&
6227 vma->vm_end >= vma->vm_mm->brk) {
6231 if (vma->vm_start <= vma->vm_mm->start_stack &&
6232 vma->vm_end >= vma->vm_mm->start_stack) {
6242 strlcpy(tmp, name, sizeof(tmp));
6246 * Since our buffer works in 8 byte units we need to align our string
6247 * size to a multiple of 8. However, we must guarantee the tail end is
6248 * zero'd out to avoid leaking random bits to userspace.
6250 size = strlen(name)+1;
6251 while (!IS_ALIGNED(size, sizeof(u64)))
6252 name[size++] = '\0';
6254 mmap_event->file_name = name;
6255 mmap_event->file_size = size;
6256 mmap_event->maj = maj;
6257 mmap_event->min = min;
6258 mmap_event->ino = ino;
6259 mmap_event->ino_generation = gen;
6260 mmap_event->prot = prot;
6261 mmap_event->flags = flags;
6263 if (!(vma->vm_flags & VM_EXEC))
6264 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6266 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6268 perf_event_aux(perf_event_mmap_output,
6275 void perf_event_mmap(struct vm_area_struct *vma)
6277 struct perf_mmap_event mmap_event;
6279 if (!atomic_read(&nr_mmap_events))
6282 mmap_event = (struct perf_mmap_event){
6288 .type = PERF_RECORD_MMAP,
6289 .misc = PERF_RECORD_MISC_USER,
6294 .start = vma->vm_start,
6295 .len = vma->vm_end - vma->vm_start,
6296 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6298 /* .maj (attr_mmap2 only) */
6299 /* .min (attr_mmap2 only) */
6300 /* .ino (attr_mmap2 only) */
6301 /* .ino_generation (attr_mmap2 only) */
6302 /* .prot (attr_mmap2 only) */
6303 /* .flags (attr_mmap2 only) */
6306 perf_event_mmap_event(&mmap_event);
6309 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6310 unsigned long size, u64 flags)
6312 struct perf_output_handle handle;
6313 struct perf_sample_data sample;
6314 struct perf_aux_event {
6315 struct perf_event_header header;
6321 .type = PERF_RECORD_AUX,
6323 .size = sizeof(rec),
6331 perf_event_header__init_id(&rec.header, &sample, event);
6332 ret = perf_output_begin(&handle, event, rec.header.size);
6337 perf_output_put(&handle, rec);
6338 perf_event__output_id_sample(event, &handle, &sample);
6340 perf_output_end(&handle);
6344 * Lost/dropped samples logging
6346 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6348 struct perf_output_handle handle;
6349 struct perf_sample_data sample;
6353 struct perf_event_header header;
6355 } lost_samples_event = {
6357 .type = PERF_RECORD_LOST_SAMPLES,
6359 .size = sizeof(lost_samples_event),
6364 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6366 ret = perf_output_begin(&handle, event,
6367 lost_samples_event.header.size);
6371 perf_output_put(&handle, lost_samples_event);
6372 perf_event__output_id_sample(event, &handle, &sample);
6373 perf_output_end(&handle);
6377 * context_switch tracking
6380 struct perf_switch_event {
6381 struct task_struct *task;
6382 struct task_struct *next_prev;
6385 struct perf_event_header header;
6391 static int perf_event_switch_match(struct perf_event *event)
6393 return event->attr.context_switch;
6396 static void perf_event_switch_output(struct perf_event *event, void *data)
6398 struct perf_switch_event *se = data;
6399 struct perf_output_handle handle;
6400 struct perf_sample_data sample;
6403 if (!perf_event_switch_match(event))
6406 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6407 if (event->ctx->task) {
6408 se->event_id.header.type = PERF_RECORD_SWITCH;
6409 se->event_id.header.size = sizeof(se->event_id.header);
6411 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6412 se->event_id.header.size = sizeof(se->event_id);
6413 se->event_id.next_prev_pid =
6414 perf_event_pid(event, se->next_prev);
6415 se->event_id.next_prev_tid =
6416 perf_event_tid(event, se->next_prev);
6419 perf_event_header__init_id(&se->event_id.header, &sample, event);
6421 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6425 if (event->ctx->task)
6426 perf_output_put(&handle, se->event_id.header);
6428 perf_output_put(&handle, se->event_id);
6430 perf_event__output_id_sample(event, &handle, &sample);
6432 perf_output_end(&handle);
6435 static void perf_event_switch(struct task_struct *task,
6436 struct task_struct *next_prev, bool sched_in)
6438 struct perf_switch_event switch_event;
6440 /* N.B. caller checks nr_switch_events != 0 */
6442 switch_event = (struct perf_switch_event){
6444 .next_prev = next_prev,
6448 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6451 /* .next_prev_pid */
6452 /* .next_prev_tid */
6456 perf_event_aux(perf_event_switch_output,
6462 * IRQ throttle logging
6465 static void perf_log_throttle(struct perf_event *event, int enable)
6467 struct perf_output_handle handle;
6468 struct perf_sample_data sample;
6472 struct perf_event_header header;
6476 } throttle_event = {
6478 .type = PERF_RECORD_THROTTLE,
6480 .size = sizeof(throttle_event),
6482 .time = perf_event_clock(event),
6483 .id = primary_event_id(event),
6484 .stream_id = event->id,
6488 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6490 perf_event_header__init_id(&throttle_event.header, &sample, event);
6492 ret = perf_output_begin(&handle, event,
6493 throttle_event.header.size);
6497 perf_output_put(&handle, throttle_event);
6498 perf_event__output_id_sample(event, &handle, &sample);
6499 perf_output_end(&handle);
6502 static void perf_log_itrace_start(struct perf_event *event)
6504 struct perf_output_handle handle;
6505 struct perf_sample_data sample;
6506 struct perf_aux_event {
6507 struct perf_event_header header;
6514 event = event->parent;
6516 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6517 event->hw.itrace_started)
6520 rec.header.type = PERF_RECORD_ITRACE_START;
6521 rec.header.misc = 0;
6522 rec.header.size = sizeof(rec);
6523 rec.pid = perf_event_pid(event, current);
6524 rec.tid = perf_event_tid(event, current);
6526 perf_event_header__init_id(&rec.header, &sample, event);
6527 ret = perf_output_begin(&handle, event, rec.header.size);
6532 perf_output_put(&handle, rec);
6533 perf_event__output_id_sample(event, &handle, &sample);
6535 perf_output_end(&handle);
6539 * Generic event overflow handling, sampling.
6542 static int __perf_event_overflow(struct perf_event *event,
6543 int throttle, struct perf_sample_data *data,
6544 struct pt_regs *regs)
6546 int events = atomic_read(&event->event_limit);
6547 struct hw_perf_event *hwc = &event->hw;
6552 * Non-sampling counters might still use the PMI to fold short
6553 * hardware counters, ignore those.
6555 if (unlikely(!is_sampling_event(event)))
6558 seq = __this_cpu_read(perf_throttled_seq);
6559 if (seq != hwc->interrupts_seq) {
6560 hwc->interrupts_seq = seq;
6561 hwc->interrupts = 1;
6564 if (unlikely(throttle
6565 && hwc->interrupts >= max_samples_per_tick)) {
6566 __this_cpu_inc(perf_throttled_count);
6567 hwc->interrupts = MAX_INTERRUPTS;
6568 perf_log_throttle(event, 0);
6569 tick_nohz_full_kick();
6574 if (event->attr.freq) {
6575 u64 now = perf_clock();
6576 s64 delta = now - hwc->freq_time_stamp;
6578 hwc->freq_time_stamp = now;
6580 if (delta > 0 && delta < 2*TICK_NSEC)
6581 perf_adjust_period(event, delta, hwc->last_period, true);
6585 * XXX event_limit might not quite work as expected on inherited
6589 event->pending_kill = POLL_IN;
6590 if (events && atomic_dec_and_test(&event->event_limit)) {
6592 event->pending_kill = POLL_HUP;
6593 event->pending_disable = 1;
6594 irq_work_queue(&event->pending);
6597 if (event->overflow_handler)
6598 event->overflow_handler(event, data, regs);
6600 perf_event_output(event, data, regs);
6602 if (*perf_event_fasync(event) && event->pending_kill) {
6603 event->pending_wakeup = 1;
6604 irq_work_queue(&event->pending);
6610 int perf_event_overflow(struct perf_event *event,
6611 struct perf_sample_data *data,
6612 struct pt_regs *regs)
6614 return __perf_event_overflow(event, 1, data, regs);
6618 * Generic software event infrastructure
6621 struct swevent_htable {
6622 struct swevent_hlist *swevent_hlist;
6623 struct mutex hlist_mutex;
6626 /* Recursion avoidance in each contexts */
6627 int recursion[PERF_NR_CONTEXTS];
6630 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6633 * We directly increment event->count and keep a second value in
6634 * event->hw.period_left to count intervals. This period event
6635 * is kept in the range [-sample_period, 0] so that we can use the
6639 u64 perf_swevent_set_period(struct perf_event *event)
6641 struct hw_perf_event *hwc = &event->hw;
6642 u64 period = hwc->last_period;
6646 hwc->last_period = hwc->sample_period;
6649 old = val = local64_read(&hwc->period_left);
6653 nr = div64_u64(period + val, period);
6654 offset = nr * period;
6656 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6662 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6663 struct perf_sample_data *data,
6664 struct pt_regs *regs)
6666 struct hw_perf_event *hwc = &event->hw;
6670 overflow = perf_swevent_set_period(event);
6672 if (hwc->interrupts == MAX_INTERRUPTS)
6675 for (; overflow; overflow--) {
6676 if (__perf_event_overflow(event, throttle,
6679 * We inhibit the overflow from happening when
6680 * hwc->interrupts == MAX_INTERRUPTS.
6688 static void perf_swevent_event(struct perf_event *event, u64 nr,
6689 struct perf_sample_data *data,
6690 struct pt_regs *regs)
6692 struct hw_perf_event *hwc = &event->hw;
6694 local64_add(nr, &event->count);
6699 if (!is_sampling_event(event))
6702 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6704 return perf_swevent_overflow(event, 1, data, regs);
6706 data->period = event->hw.last_period;
6708 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6709 return perf_swevent_overflow(event, 1, data, regs);
6711 if (local64_add_negative(nr, &hwc->period_left))
6714 perf_swevent_overflow(event, 0, data, regs);
6717 static int perf_exclude_event(struct perf_event *event,
6718 struct pt_regs *regs)
6720 if (event->hw.state & PERF_HES_STOPPED)
6724 if (event->attr.exclude_user && user_mode(regs))
6727 if (event->attr.exclude_kernel && !user_mode(regs))
6734 static int perf_swevent_match(struct perf_event *event,
6735 enum perf_type_id type,
6737 struct perf_sample_data *data,
6738 struct pt_regs *regs)
6740 if (event->attr.type != type)
6743 if (event->attr.config != event_id)
6746 if (perf_exclude_event(event, regs))
6752 static inline u64 swevent_hash(u64 type, u32 event_id)
6754 u64 val = event_id | (type << 32);
6756 return hash_64(val, SWEVENT_HLIST_BITS);
6759 static inline struct hlist_head *
6760 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6762 u64 hash = swevent_hash(type, event_id);
6764 return &hlist->heads[hash];
6767 /* For the read side: events when they trigger */
6768 static inline struct hlist_head *
6769 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6771 struct swevent_hlist *hlist;
6773 hlist = rcu_dereference(swhash->swevent_hlist);
6777 return __find_swevent_head(hlist, type, event_id);
6780 /* For the event head insertion and removal in the hlist */
6781 static inline struct hlist_head *
6782 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6784 struct swevent_hlist *hlist;
6785 u32 event_id = event->attr.config;
6786 u64 type = event->attr.type;
6789 * Event scheduling is always serialized against hlist allocation
6790 * and release. Which makes the protected version suitable here.
6791 * The context lock guarantees that.
6793 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6794 lockdep_is_held(&event->ctx->lock));
6798 return __find_swevent_head(hlist, type, event_id);
6801 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6803 struct perf_sample_data *data,
6804 struct pt_regs *regs)
6806 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6807 struct perf_event *event;
6808 struct hlist_head *head;
6811 head = find_swevent_head_rcu(swhash, type, event_id);
6815 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6816 if (perf_swevent_match(event, type, event_id, data, regs))
6817 perf_swevent_event(event, nr, data, regs);
6823 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6825 int perf_swevent_get_recursion_context(void)
6827 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6829 return get_recursion_context(swhash->recursion);
6831 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6833 inline void perf_swevent_put_recursion_context(int rctx)
6835 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6837 put_recursion_context(swhash->recursion, rctx);
6840 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6842 struct perf_sample_data data;
6844 if (WARN_ON_ONCE(!regs))
6847 perf_sample_data_init(&data, addr, 0);
6848 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6851 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6855 preempt_disable_notrace();
6856 rctx = perf_swevent_get_recursion_context();
6857 if (unlikely(rctx < 0))
6860 ___perf_sw_event(event_id, nr, regs, addr);
6862 perf_swevent_put_recursion_context(rctx);
6864 preempt_enable_notrace();
6867 static void perf_swevent_read(struct perf_event *event)
6871 static int perf_swevent_add(struct perf_event *event, int flags)
6873 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6874 struct hw_perf_event *hwc = &event->hw;
6875 struct hlist_head *head;
6877 if (is_sampling_event(event)) {
6878 hwc->last_period = hwc->sample_period;
6879 perf_swevent_set_period(event);
6882 hwc->state = !(flags & PERF_EF_START);
6884 head = find_swevent_head(swhash, event);
6885 if (WARN_ON_ONCE(!head))
6888 hlist_add_head_rcu(&event->hlist_entry, head);
6889 perf_event_update_userpage(event);
6894 static void perf_swevent_del(struct perf_event *event, int flags)
6896 hlist_del_rcu(&event->hlist_entry);
6899 static void perf_swevent_start(struct perf_event *event, int flags)
6901 event->hw.state = 0;
6904 static void perf_swevent_stop(struct perf_event *event, int flags)
6906 event->hw.state = PERF_HES_STOPPED;
6909 /* Deref the hlist from the update side */
6910 static inline struct swevent_hlist *
6911 swevent_hlist_deref(struct swevent_htable *swhash)
6913 return rcu_dereference_protected(swhash->swevent_hlist,
6914 lockdep_is_held(&swhash->hlist_mutex));
6917 static void swevent_hlist_release(struct swevent_htable *swhash)
6919 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6924 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6925 kfree_rcu(hlist, rcu_head);
6928 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6930 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6932 mutex_lock(&swhash->hlist_mutex);
6934 if (!--swhash->hlist_refcount)
6935 swevent_hlist_release(swhash);
6937 mutex_unlock(&swhash->hlist_mutex);
6940 static void swevent_hlist_put(struct perf_event *event)
6944 for_each_possible_cpu(cpu)
6945 swevent_hlist_put_cpu(event, cpu);
6948 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6950 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6953 mutex_lock(&swhash->hlist_mutex);
6954 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6955 struct swevent_hlist *hlist;
6957 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6962 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6964 swhash->hlist_refcount++;
6966 mutex_unlock(&swhash->hlist_mutex);
6971 static int swevent_hlist_get(struct perf_event *event)
6974 int cpu, failed_cpu;
6977 for_each_possible_cpu(cpu) {
6978 err = swevent_hlist_get_cpu(event, cpu);
6988 for_each_possible_cpu(cpu) {
6989 if (cpu == failed_cpu)
6991 swevent_hlist_put_cpu(event, cpu);
6998 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
7000 static void sw_perf_event_destroy(struct perf_event *event)
7002 u64 event_id = event->attr.config;
7004 WARN_ON(event->parent);
7006 static_key_slow_dec(&perf_swevent_enabled[event_id]);
7007 swevent_hlist_put(event);
7010 static int perf_swevent_init(struct perf_event *event)
7012 u64 event_id = event->attr.config;
7014 if (event->attr.type != PERF_TYPE_SOFTWARE)
7018 * no branch sampling for software events
7020 if (has_branch_stack(event))
7024 case PERF_COUNT_SW_CPU_CLOCK:
7025 case PERF_COUNT_SW_TASK_CLOCK:
7032 if (event_id >= PERF_COUNT_SW_MAX)
7035 if (!event->parent) {
7038 err = swevent_hlist_get(event);
7042 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7043 event->destroy = sw_perf_event_destroy;
7049 static struct pmu perf_swevent = {
7050 .task_ctx_nr = perf_sw_context,
7052 .capabilities = PERF_PMU_CAP_NO_NMI,
7054 .event_init = perf_swevent_init,
7055 .add = perf_swevent_add,
7056 .del = perf_swevent_del,
7057 .start = perf_swevent_start,
7058 .stop = perf_swevent_stop,
7059 .read = perf_swevent_read,
7062 #ifdef CONFIG_EVENT_TRACING
7064 static int perf_tp_filter_match(struct perf_event *event,
7065 struct perf_sample_data *data)
7067 void *record = data->raw->data;
7069 /* only top level events have filters set */
7071 event = event->parent;
7073 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7078 static int perf_tp_event_match(struct perf_event *event,
7079 struct perf_sample_data *data,
7080 struct pt_regs *regs)
7082 if (event->hw.state & PERF_HES_STOPPED)
7085 * All tracepoints are from kernel-space.
7087 if (event->attr.exclude_kernel)
7090 if (!perf_tp_filter_match(event, data))
7096 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
7097 struct pt_regs *regs, struct hlist_head *head, int rctx,
7098 struct task_struct *task)
7100 struct perf_sample_data data;
7101 struct perf_event *event;
7103 struct perf_raw_record raw = {
7108 perf_sample_data_init(&data, addr, 0);
7111 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7112 if (perf_tp_event_match(event, &data, regs))
7113 perf_swevent_event(event, count, &data, regs);
7117 * If we got specified a target task, also iterate its context and
7118 * deliver this event there too.
7120 if (task && task != current) {
7121 struct perf_event_context *ctx;
7122 struct trace_entry *entry = record;
7125 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7129 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7130 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7132 if (event->attr.config != entry->type)
7134 if (perf_tp_event_match(event, &data, regs))
7135 perf_swevent_event(event, count, &data, regs);
7141 perf_swevent_put_recursion_context(rctx);
7143 EXPORT_SYMBOL_GPL(perf_tp_event);
7145 static void tp_perf_event_destroy(struct perf_event *event)
7147 perf_trace_destroy(event);
7150 static int perf_tp_event_init(struct perf_event *event)
7154 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7158 * no branch sampling for tracepoint events
7160 if (has_branch_stack(event))
7163 err = perf_trace_init(event);
7167 event->destroy = tp_perf_event_destroy;
7172 static struct pmu perf_tracepoint = {
7173 .task_ctx_nr = perf_sw_context,
7175 .event_init = perf_tp_event_init,
7176 .add = perf_trace_add,
7177 .del = perf_trace_del,
7178 .start = perf_swevent_start,
7179 .stop = perf_swevent_stop,
7180 .read = perf_swevent_read,
7183 static inline void perf_tp_register(void)
7185 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7188 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7193 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7196 filter_str = strndup_user(arg, PAGE_SIZE);
7197 if (IS_ERR(filter_str))
7198 return PTR_ERR(filter_str);
7200 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7206 static void perf_event_free_filter(struct perf_event *event)
7208 ftrace_profile_free_filter(event);
7211 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7213 struct bpf_prog *prog;
7215 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7218 if (event->tp_event->prog)
7221 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7222 /* bpf programs can only be attached to u/kprobes */
7225 prog = bpf_prog_get(prog_fd);
7227 return PTR_ERR(prog);
7229 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7230 /* valid fd, but invalid bpf program type */
7235 event->tp_event->prog = prog;
7240 static void perf_event_free_bpf_prog(struct perf_event *event)
7242 struct bpf_prog *prog;
7244 if (!event->tp_event)
7247 prog = event->tp_event->prog;
7249 event->tp_event->prog = NULL;
7250 bpf_prog_put_rcu(prog);
7256 static inline void perf_tp_register(void)
7260 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7265 static void perf_event_free_filter(struct perf_event *event)
7269 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7274 static void perf_event_free_bpf_prog(struct perf_event *event)
7277 #endif /* CONFIG_EVENT_TRACING */
7279 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7280 void perf_bp_event(struct perf_event *bp, void *data)
7282 struct perf_sample_data sample;
7283 struct pt_regs *regs = data;
7285 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7287 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7288 perf_swevent_event(bp, 1, &sample, regs);
7292 static int perf_event_drv_configs(struct perf_event *event,
7295 if (!event->pmu->get_drv_configs)
7298 return event->pmu->get_drv_configs(event, arg);
7302 * hrtimer based swevent callback
7305 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7307 enum hrtimer_restart ret = HRTIMER_RESTART;
7308 struct perf_sample_data data;
7309 struct pt_regs *regs;
7310 struct perf_event *event;
7313 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7315 if (event->state != PERF_EVENT_STATE_ACTIVE)
7316 return HRTIMER_NORESTART;
7318 event->pmu->read(event);
7320 perf_sample_data_init(&data, 0, event->hw.last_period);
7321 regs = get_irq_regs();
7323 if (regs && !perf_exclude_event(event, regs)) {
7324 if (!(event->attr.exclude_idle && is_idle_task(current)))
7325 if (__perf_event_overflow(event, 1, &data, regs))
7326 ret = HRTIMER_NORESTART;
7329 period = max_t(u64, 10000, event->hw.sample_period);
7330 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7335 static void perf_swevent_start_hrtimer(struct perf_event *event)
7337 struct hw_perf_event *hwc = &event->hw;
7340 if (!is_sampling_event(event))
7343 period = local64_read(&hwc->period_left);
7348 local64_set(&hwc->period_left, 0);
7350 period = max_t(u64, 10000, hwc->sample_period);
7352 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7353 HRTIMER_MODE_REL_PINNED);
7356 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7358 struct hw_perf_event *hwc = &event->hw;
7360 if (is_sampling_event(event)) {
7361 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7362 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7364 hrtimer_cancel(&hwc->hrtimer);
7368 static void perf_swevent_init_hrtimer(struct perf_event *event)
7370 struct hw_perf_event *hwc = &event->hw;
7372 if (!is_sampling_event(event))
7375 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7376 hwc->hrtimer.function = perf_swevent_hrtimer;
7379 * Since hrtimers have a fixed rate, we can do a static freq->period
7380 * mapping and avoid the whole period adjust feedback stuff.
7382 if (event->attr.freq) {
7383 long freq = event->attr.sample_freq;
7385 event->attr.sample_period = NSEC_PER_SEC / freq;
7386 hwc->sample_period = event->attr.sample_period;
7387 local64_set(&hwc->period_left, hwc->sample_period);
7388 hwc->last_period = hwc->sample_period;
7389 event->attr.freq = 0;
7394 * Software event: cpu wall time clock
7397 static void cpu_clock_event_update(struct perf_event *event)
7402 now = local_clock();
7403 prev = local64_xchg(&event->hw.prev_count, now);
7404 local64_add(now - prev, &event->count);
7407 static void cpu_clock_event_start(struct perf_event *event, int flags)
7409 local64_set(&event->hw.prev_count, local_clock());
7410 perf_swevent_start_hrtimer(event);
7413 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7415 perf_swevent_cancel_hrtimer(event);
7416 cpu_clock_event_update(event);
7419 static int cpu_clock_event_add(struct perf_event *event, int flags)
7421 if (flags & PERF_EF_START)
7422 cpu_clock_event_start(event, flags);
7423 perf_event_update_userpage(event);
7428 static void cpu_clock_event_del(struct perf_event *event, int flags)
7430 cpu_clock_event_stop(event, flags);
7433 static void cpu_clock_event_read(struct perf_event *event)
7435 cpu_clock_event_update(event);
7438 static int cpu_clock_event_init(struct perf_event *event)
7440 if (event->attr.type != PERF_TYPE_SOFTWARE)
7443 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7447 * no branch sampling for software events
7449 if (has_branch_stack(event))
7452 perf_swevent_init_hrtimer(event);
7457 static struct pmu perf_cpu_clock = {
7458 .task_ctx_nr = perf_sw_context,
7460 .capabilities = PERF_PMU_CAP_NO_NMI,
7462 .event_init = cpu_clock_event_init,
7463 .add = cpu_clock_event_add,
7464 .del = cpu_clock_event_del,
7465 .start = cpu_clock_event_start,
7466 .stop = cpu_clock_event_stop,
7467 .read = cpu_clock_event_read,
7471 * Software event: task time clock
7474 static void task_clock_event_update(struct perf_event *event, u64 now)
7479 prev = local64_xchg(&event->hw.prev_count, now);
7481 local64_add(delta, &event->count);
7484 static void task_clock_event_start(struct perf_event *event, int flags)
7486 local64_set(&event->hw.prev_count, event->ctx->time);
7487 perf_swevent_start_hrtimer(event);
7490 static void task_clock_event_stop(struct perf_event *event, int flags)
7492 perf_swevent_cancel_hrtimer(event);
7493 task_clock_event_update(event, event->ctx->time);
7496 static int task_clock_event_add(struct perf_event *event, int flags)
7498 if (flags & PERF_EF_START)
7499 task_clock_event_start(event, flags);
7500 perf_event_update_userpage(event);
7505 static void task_clock_event_del(struct perf_event *event, int flags)
7507 task_clock_event_stop(event, PERF_EF_UPDATE);
7510 static void task_clock_event_read(struct perf_event *event)
7512 u64 now = perf_clock();
7513 u64 delta = now - event->ctx->timestamp;
7514 u64 time = event->ctx->time + delta;
7516 task_clock_event_update(event, time);
7519 static int task_clock_event_init(struct perf_event *event)
7521 if (event->attr.type != PERF_TYPE_SOFTWARE)
7524 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7528 * no branch sampling for software events
7530 if (has_branch_stack(event))
7533 perf_swevent_init_hrtimer(event);
7538 static struct pmu perf_task_clock = {
7539 .task_ctx_nr = perf_sw_context,
7541 .capabilities = PERF_PMU_CAP_NO_NMI,
7543 .event_init = task_clock_event_init,
7544 .add = task_clock_event_add,
7545 .del = task_clock_event_del,
7546 .start = task_clock_event_start,
7547 .stop = task_clock_event_stop,
7548 .read = task_clock_event_read,
7551 static void perf_pmu_nop_void(struct pmu *pmu)
7555 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7559 static int perf_pmu_nop_int(struct pmu *pmu)
7564 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7566 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7568 __this_cpu_write(nop_txn_flags, flags);
7570 if (flags & ~PERF_PMU_TXN_ADD)
7573 perf_pmu_disable(pmu);
7576 static int perf_pmu_commit_txn(struct pmu *pmu)
7578 unsigned int flags = __this_cpu_read(nop_txn_flags);
7580 __this_cpu_write(nop_txn_flags, 0);
7582 if (flags & ~PERF_PMU_TXN_ADD)
7585 perf_pmu_enable(pmu);
7589 static void perf_pmu_cancel_txn(struct pmu *pmu)
7591 unsigned int flags = __this_cpu_read(nop_txn_flags);
7593 __this_cpu_write(nop_txn_flags, 0);
7595 if (flags & ~PERF_PMU_TXN_ADD)
7598 perf_pmu_enable(pmu);
7601 static int perf_event_idx_default(struct perf_event *event)
7607 * Ensures all contexts with the same task_ctx_nr have the same
7608 * pmu_cpu_context too.
7610 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7617 list_for_each_entry(pmu, &pmus, entry) {
7618 if (pmu->task_ctx_nr == ctxn)
7619 return pmu->pmu_cpu_context;
7625 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7629 for_each_possible_cpu(cpu) {
7630 struct perf_cpu_context *cpuctx;
7632 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7634 if (cpuctx->unique_pmu == old_pmu)
7635 cpuctx->unique_pmu = pmu;
7639 static void free_pmu_context(struct pmu *pmu)
7643 mutex_lock(&pmus_lock);
7645 * Like a real lame refcount.
7647 list_for_each_entry(i, &pmus, entry) {
7648 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7649 update_pmu_context(i, pmu);
7654 free_percpu(pmu->pmu_cpu_context);
7656 mutex_unlock(&pmus_lock);
7658 static struct idr pmu_idr;
7661 type_show(struct device *dev, struct device_attribute *attr, char *page)
7663 struct pmu *pmu = dev_get_drvdata(dev);
7665 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7667 static DEVICE_ATTR_RO(type);
7670 perf_event_mux_interval_ms_show(struct device *dev,
7671 struct device_attribute *attr,
7674 struct pmu *pmu = dev_get_drvdata(dev);
7676 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7679 static DEFINE_MUTEX(mux_interval_mutex);
7682 perf_event_mux_interval_ms_store(struct device *dev,
7683 struct device_attribute *attr,
7684 const char *buf, size_t count)
7686 struct pmu *pmu = dev_get_drvdata(dev);
7687 int timer, cpu, ret;
7689 ret = kstrtoint(buf, 0, &timer);
7696 /* same value, noting to do */
7697 if (timer == pmu->hrtimer_interval_ms)
7700 mutex_lock(&mux_interval_mutex);
7701 pmu->hrtimer_interval_ms = timer;
7703 /* update all cpuctx for this PMU */
7705 for_each_online_cpu(cpu) {
7706 struct perf_cpu_context *cpuctx;
7707 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7708 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7710 cpu_function_call(cpu,
7711 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7714 mutex_unlock(&mux_interval_mutex);
7718 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7720 static struct attribute *pmu_dev_attrs[] = {
7721 &dev_attr_type.attr,
7722 &dev_attr_perf_event_mux_interval_ms.attr,
7725 ATTRIBUTE_GROUPS(pmu_dev);
7727 static int pmu_bus_running;
7728 static struct bus_type pmu_bus = {
7729 .name = "event_source",
7730 .dev_groups = pmu_dev_groups,
7733 static void pmu_dev_release(struct device *dev)
7738 static int pmu_dev_alloc(struct pmu *pmu)
7742 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7746 pmu->dev->groups = pmu->attr_groups;
7747 device_initialize(pmu->dev);
7748 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7752 dev_set_drvdata(pmu->dev, pmu);
7753 pmu->dev->bus = &pmu_bus;
7754 pmu->dev->release = pmu_dev_release;
7755 ret = device_add(pmu->dev);
7763 put_device(pmu->dev);
7767 static struct lock_class_key cpuctx_mutex;
7768 static struct lock_class_key cpuctx_lock;
7770 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7774 mutex_lock(&pmus_lock);
7776 pmu->pmu_disable_count = alloc_percpu(int);
7777 if (!pmu->pmu_disable_count)
7786 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7794 if (pmu_bus_running) {
7795 ret = pmu_dev_alloc(pmu);
7801 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7802 if (pmu->pmu_cpu_context)
7803 goto got_cpu_context;
7806 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7807 if (!pmu->pmu_cpu_context)
7810 for_each_possible_cpu(cpu) {
7811 struct perf_cpu_context *cpuctx;
7813 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7814 __perf_event_init_context(&cpuctx->ctx);
7815 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7816 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7817 cpuctx->ctx.pmu = pmu;
7819 __perf_mux_hrtimer_init(cpuctx, cpu);
7821 cpuctx->unique_pmu = pmu;
7825 if (!pmu->start_txn) {
7826 if (pmu->pmu_enable) {
7828 * If we have pmu_enable/pmu_disable calls, install
7829 * transaction stubs that use that to try and batch
7830 * hardware accesses.
7832 pmu->start_txn = perf_pmu_start_txn;
7833 pmu->commit_txn = perf_pmu_commit_txn;
7834 pmu->cancel_txn = perf_pmu_cancel_txn;
7836 pmu->start_txn = perf_pmu_nop_txn;
7837 pmu->commit_txn = perf_pmu_nop_int;
7838 pmu->cancel_txn = perf_pmu_nop_void;
7842 if (!pmu->pmu_enable) {
7843 pmu->pmu_enable = perf_pmu_nop_void;
7844 pmu->pmu_disable = perf_pmu_nop_void;
7847 if (!pmu->event_idx)
7848 pmu->event_idx = perf_event_idx_default;
7850 list_add_rcu(&pmu->entry, &pmus);
7851 atomic_set(&pmu->exclusive_cnt, 0);
7854 mutex_unlock(&pmus_lock);
7859 device_del(pmu->dev);
7860 put_device(pmu->dev);
7863 if (pmu->type >= PERF_TYPE_MAX)
7864 idr_remove(&pmu_idr, pmu->type);
7867 free_percpu(pmu->pmu_disable_count);
7870 EXPORT_SYMBOL_GPL(perf_pmu_register);
7872 void perf_pmu_unregister(struct pmu *pmu)
7874 mutex_lock(&pmus_lock);
7875 list_del_rcu(&pmu->entry);
7876 mutex_unlock(&pmus_lock);
7879 * We dereference the pmu list under both SRCU and regular RCU, so
7880 * synchronize against both of those.
7882 synchronize_srcu(&pmus_srcu);
7885 free_percpu(pmu->pmu_disable_count);
7886 if (pmu->type >= PERF_TYPE_MAX)
7887 idr_remove(&pmu_idr, pmu->type);
7888 device_del(pmu->dev);
7889 put_device(pmu->dev);
7890 free_pmu_context(pmu);
7892 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7894 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7896 struct perf_event_context *ctx = NULL;
7899 if (!try_module_get(pmu->module))
7902 if (event->group_leader != event) {
7904 * This ctx->mutex can nest when we're called through
7905 * inheritance. See the perf_event_ctx_lock_nested() comment.
7907 ctx = perf_event_ctx_lock_nested(event->group_leader,
7908 SINGLE_DEPTH_NESTING);
7913 ret = pmu->event_init(event);
7916 perf_event_ctx_unlock(event->group_leader, ctx);
7919 module_put(pmu->module);
7924 static struct pmu *perf_init_event(struct perf_event *event)
7926 struct pmu *pmu = NULL;
7930 idx = srcu_read_lock(&pmus_srcu);
7933 pmu = idr_find(&pmu_idr, event->attr.type);
7936 ret = perf_try_init_event(pmu, event);
7942 list_for_each_entry_rcu(pmu, &pmus, entry) {
7943 ret = perf_try_init_event(pmu, event);
7947 if (ret != -ENOENT) {
7952 pmu = ERR_PTR(-ENOENT);
7954 srcu_read_unlock(&pmus_srcu, idx);
7959 static void account_event_cpu(struct perf_event *event, int cpu)
7964 if (is_cgroup_event(event))
7965 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7968 static void account_event(struct perf_event *event)
7973 if (event->attach_state & PERF_ATTACH_TASK)
7974 static_key_slow_inc(&perf_sched_events.key);
7975 if (event->attr.mmap || event->attr.mmap_data)
7976 atomic_inc(&nr_mmap_events);
7977 if (event->attr.comm)
7978 atomic_inc(&nr_comm_events);
7979 if (event->attr.task)
7980 atomic_inc(&nr_task_events);
7981 if (event->attr.freq) {
7982 if (atomic_inc_return(&nr_freq_events) == 1)
7983 tick_nohz_full_kick_all();
7985 if (event->attr.context_switch) {
7986 atomic_inc(&nr_switch_events);
7987 static_key_slow_inc(&perf_sched_events.key);
7989 if (has_branch_stack(event))
7990 static_key_slow_inc(&perf_sched_events.key);
7991 if (is_cgroup_event(event))
7992 static_key_slow_inc(&perf_sched_events.key);
7994 account_event_cpu(event, event->cpu);
7998 * Allocate and initialize a event structure
8000 static struct perf_event *
8001 perf_event_alloc(struct perf_event_attr *attr, int cpu,
8002 struct task_struct *task,
8003 struct perf_event *group_leader,
8004 struct perf_event *parent_event,
8005 perf_overflow_handler_t overflow_handler,
8006 void *context, int cgroup_fd)
8009 struct perf_event *event;
8010 struct hw_perf_event *hwc;
8013 if ((unsigned)cpu >= nr_cpu_ids) {
8014 if (!task || cpu != -1)
8015 return ERR_PTR(-EINVAL);
8018 event = kzalloc(sizeof(*event), GFP_KERNEL);
8020 return ERR_PTR(-ENOMEM);
8023 * Single events are their own group leaders, with an
8024 * empty sibling list:
8027 group_leader = event;
8029 mutex_init(&event->child_mutex);
8030 INIT_LIST_HEAD(&event->child_list);
8032 INIT_LIST_HEAD(&event->group_entry);
8033 INIT_LIST_HEAD(&event->event_entry);
8034 INIT_LIST_HEAD(&event->sibling_list);
8035 INIT_LIST_HEAD(&event->rb_entry);
8036 INIT_LIST_HEAD(&event->active_entry);
8037 INIT_LIST_HEAD(&event->drv_configs);
8038 INIT_HLIST_NODE(&event->hlist_entry);
8041 init_waitqueue_head(&event->waitq);
8042 init_irq_work(&event->pending, perf_pending_event);
8044 mutex_init(&event->mmap_mutex);
8046 atomic_long_set(&event->refcount, 1);
8048 event->attr = *attr;
8049 event->group_leader = group_leader;
8053 event->parent = parent_event;
8055 event->ns = get_pid_ns(task_active_pid_ns(current));
8056 event->id = atomic64_inc_return(&perf_event_id);
8058 event->state = PERF_EVENT_STATE_INACTIVE;
8061 event->attach_state = PERF_ATTACH_TASK;
8063 * XXX pmu::event_init needs to know what task to account to
8064 * and we cannot use the ctx information because we need the
8065 * pmu before we get a ctx.
8067 event->hw.target = task;
8070 event->clock = &local_clock;
8072 event->clock = parent_event->clock;
8074 if (!overflow_handler && parent_event) {
8075 overflow_handler = parent_event->overflow_handler;
8076 context = parent_event->overflow_handler_context;
8079 event->overflow_handler = overflow_handler;
8080 event->overflow_handler_context = context;
8082 perf_event__state_init(event);
8087 hwc->sample_period = attr->sample_period;
8088 if (attr->freq && attr->sample_freq)
8089 hwc->sample_period = 1;
8090 hwc->last_period = hwc->sample_period;
8092 local64_set(&hwc->period_left, hwc->sample_period);
8095 * we currently do not support PERF_FORMAT_GROUP on inherited events
8097 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8100 if (!has_branch_stack(event))
8101 event->attr.branch_sample_type = 0;
8103 if (cgroup_fd != -1) {
8104 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8109 pmu = perf_init_event(event);
8112 else if (IS_ERR(pmu)) {
8117 err = exclusive_event_init(event);
8121 if (!event->parent) {
8122 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8123 err = get_callchain_buffers();
8129 /* symmetric to unaccount_event() in _free_event() */
8130 account_event(event);
8135 exclusive_event_destroy(event);
8139 event->destroy(event);
8140 module_put(pmu->module);
8142 if (is_cgroup_event(event))
8143 perf_detach_cgroup(event);
8145 put_pid_ns(event->ns);
8148 return ERR_PTR(err);
8151 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8152 struct perf_event_attr *attr)
8157 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8161 * zero the full structure, so that a short copy will be nice.
8163 memset(attr, 0, sizeof(*attr));
8165 ret = get_user(size, &uattr->size);
8169 if (size > PAGE_SIZE) /* silly large */
8172 if (!size) /* abi compat */
8173 size = PERF_ATTR_SIZE_VER0;
8175 if (size < PERF_ATTR_SIZE_VER0)
8179 * If we're handed a bigger struct than we know of,
8180 * ensure all the unknown bits are 0 - i.e. new
8181 * user-space does not rely on any kernel feature
8182 * extensions we dont know about yet.
8184 if (size > sizeof(*attr)) {
8185 unsigned char __user *addr;
8186 unsigned char __user *end;
8189 addr = (void __user *)uattr + sizeof(*attr);
8190 end = (void __user *)uattr + size;
8192 for (; addr < end; addr++) {
8193 ret = get_user(val, addr);
8199 size = sizeof(*attr);
8202 ret = copy_from_user(attr, uattr, size);
8206 if (attr->__reserved_1)
8209 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8212 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8215 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8216 u64 mask = attr->branch_sample_type;
8218 /* only using defined bits */
8219 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8222 /* at least one branch bit must be set */
8223 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8226 /* propagate priv level, when not set for branch */
8227 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8229 /* exclude_kernel checked on syscall entry */
8230 if (!attr->exclude_kernel)
8231 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8233 if (!attr->exclude_user)
8234 mask |= PERF_SAMPLE_BRANCH_USER;
8236 if (!attr->exclude_hv)
8237 mask |= PERF_SAMPLE_BRANCH_HV;
8239 * adjust user setting (for HW filter setup)
8241 attr->branch_sample_type = mask;
8243 /* privileged levels capture (kernel, hv): check permissions */
8244 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8245 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8249 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8250 ret = perf_reg_validate(attr->sample_regs_user);
8255 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8256 if (!arch_perf_have_user_stack_dump())
8260 * We have __u32 type for the size, but so far
8261 * we can only use __u16 as maximum due to the
8262 * __u16 sample size limit.
8264 if (attr->sample_stack_user >= USHRT_MAX)
8266 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8270 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8271 ret = perf_reg_validate(attr->sample_regs_intr);
8276 put_user(sizeof(*attr), &uattr->size);
8282 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8284 struct ring_buffer *rb = NULL;
8290 /* don't allow circular references */
8291 if (event == output_event)
8295 * Don't allow cross-cpu buffers
8297 if (output_event->cpu != event->cpu)
8301 * If its not a per-cpu rb, it must be the same task.
8303 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8307 * Mixing clocks in the same buffer is trouble you don't need.
8309 if (output_event->clock != event->clock)
8313 * If both events generate aux data, they must be on the same PMU
8315 if (has_aux(event) && has_aux(output_event) &&
8316 event->pmu != output_event->pmu)
8320 mutex_lock(&event->mmap_mutex);
8321 /* Can't redirect output if we've got an active mmap() */
8322 if (atomic_read(&event->mmap_count))
8326 /* get the rb we want to redirect to */
8327 rb = ring_buffer_get(output_event);
8332 ring_buffer_attach(event, rb);
8336 mutex_unlock(&event->mmap_mutex);
8342 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8348 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8351 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8353 bool nmi_safe = false;
8356 case CLOCK_MONOTONIC:
8357 event->clock = &ktime_get_mono_fast_ns;
8361 case CLOCK_MONOTONIC_RAW:
8362 event->clock = &ktime_get_raw_fast_ns;
8366 case CLOCK_REALTIME:
8367 event->clock = &ktime_get_real_ns;
8370 case CLOCK_BOOTTIME:
8371 event->clock = &ktime_get_boot_ns;
8375 event->clock = &ktime_get_tai_ns;
8382 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8389 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8391 * @attr_uptr: event_id type attributes for monitoring/sampling
8394 * @group_fd: group leader event fd
8396 SYSCALL_DEFINE5(perf_event_open,
8397 struct perf_event_attr __user *, attr_uptr,
8398 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8400 struct perf_event *group_leader = NULL, *output_event = NULL;
8401 struct perf_event *event, *sibling;
8402 struct perf_event_attr attr;
8403 struct perf_event_context *ctx, *uninitialized_var(gctx);
8404 struct file *event_file = NULL;
8405 struct fd group = {NULL, 0};
8406 struct task_struct *task = NULL;
8411 int f_flags = O_RDWR;
8414 /* for future expandability... */
8415 if (flags & ~PERF_FLAG_ALL)
8418 err = perf_copy_attr(attr_uptr, &attr);
8422 if (!attr.exclude_kernel) {
8423 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8428 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8431 if (attr.sample_period & (1ULL << 63))
8436 * In cgroup mode, the pid argument is used to pass the fd
8437 * opened to the cgroup directory in cgroupfs. The cpu argument
8438 * designates the cpu on which to monitor threads from that
8441 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8444 if (flags & PERF_FLAG_FD_CLOEXEC)
8445 f_flags |= O_CLOEXEC;
8447 event_fd = get_unused_fd_flags(f_flags);
8451 if (group_fd != -1) {
8452 err = perf_fget_light(group_fd, &group);
8455 group_leader = group.file->private_data;
8456 if (flags & PERF_FLAG_FD_OUTPUT)
8457 output_event = group_leader;
8458 if (flags & PERF_FLAG_FD_NO_GROUP)
8459 group_leader = NULL;
8462 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8463 task = find_lively_task_by_vpid(pid);
8465 err = PTR_ERR(task);
8470 if (task && group_leader &&
8471 group_leader->attr.inherit != attr.inherit) {
8479 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
8484 * Reuse ptrace permission checks for now.
8486 * We must hold cred_guard_mutex across this and any potential
8487 * perf_install_in_context() call for this new event to
8488 * serialize against exec() altering our credentials (and the
8489 * perf_event_exit_task() that could imply).
8492 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
8496 if (flags & PERF_FLAG_PID_CGROUP)
8499 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8500 NULL, NULL, cgroup_fd);
8501 if (IS_ERR(event)) {
8502 err = PTR_ERR(event);
8506 if (is_sampling_event(event)) {
8507 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8514 * Special case software events and allow them to be part of
8515 * any hardware group.
8519 if (attr.use_clockid) {
8520 err = perf_event_set_clock(event, attr.clockid);
8526 (is_software_event(event) != is_software_event(group_leader))) {
8527 if (is_software_event(event)) {
8529 * If event and group_leader are not both a software
8530 * event, and event is, then group leader is not.
8532 * Allow the addition of software events to !software
8533 * groups, this is safe because software events never
8536 pmu = group_leader->pmu;
8537 } else if (is_software_event(group_leader) &&
8538 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8540 * In case the group is a pure software group, and we
8541 * try to add a hardware event, move the whole group to
8542 * the hardware context.
8549 * Get the target context (task or percpu):
8551 ctx = find_get_context(pmu, task, event);
8557 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8563 * Look up the group leader (we will attach this event to it):
8569 * Do not allow a recursive hierarchy (this new sibling
8570 * becoming part of another group-sibling):
8572 if (group_leader->group_leader != group_leader)
8575 /* All events in a group should have the same clock */
8576 if (group_leader->clock != event->clock)
8580 * Do not allow to attach to a group in a different
8581 * task or CPU context:
8585 * Make sure we're both on the same task, or both
8588 if (group_leader->ctx->task != ctx->task)
8592 * Make sure we're both events for the same CPU;
8593 * grouping events for different CPUs is broken; since
8594 * you can never concurrently schedule them anyhow.
8596 if (group_leader->cpu != event->cpu)
8599 if (group_leader->ctx != ctx)
8604 * Only a group leader can be exclusive or pinned
8606 if (attr.exclusive || attr.pinned)
8611 err = perf_event_set_output(event, output_event);
8616 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8618 if (IS_ERR(event_file)) {
8619 err = PTR_ERR(event_file);
8625 gctx = group_leader->ctx;
8626 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8628 mutex_lock(&ctx->mutex);
8631 if (!perf_event_validate_size(event)) {
8637 * Must be under the same ctx::mutex as perf_install_in_context(),
8638 * because we need to serialize with concurrent event creation.
8640 if (!exclusive_event_installable(event, ctx)) {
8641 /* exclusive and group stuff are assumed mutually exclusive */
8642 WARN_ON_ONCE(move_group);
8648 WARN_ON_ONCE(ctx->parent_ctx);
8651 * This is the point on no return; we cannot fail hereafter. This is
8652 * where we start modifying current state.
8657 * See perf_event_ctx_lock() for comments on the details
8658 * of swizzling perf_event::ctx.
8660 perf_remove_from_context(group_leader, false);
8662 list_for_each_entry(sibling, &group_leader->sibling_list,
8664 perf_remove_from_context(sibling, false);
8669 * Wait for everybody to stop referencing the events through
8670 * the old lists, before installing it on new lists.
8675 * Install the group siblings before the group leader.
8677 * Because a group leader will try and install the entire group
8678 * (through the sibling list, which is still in-tact), we can
8679 * end up with siblings installed in the wrong context.
8681 * By installing siblings first we NO-OP because they're not
8682 * reachable through the group lists.
8684 list_for_each_entry(sibling, &group_leader->sibling_list,
8686 perf_event__state_init(sibling);
8687 perf_install_in_context(ctx, sibling, sibling->cpu);
8692 * Removing from the context ends up with disabled
8693 * event. What we want here is event in the initial
8694 * startup state, ready to be add into new context.
8696 perf_event__state_init(group_leader);
8697 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8701 * Now that all events are installed in @ctx, nothing
8702 * references @gctx anymore, so drop the last reference we have
8709 * Precalculate sample_data sizes; do while holding ctx::mutex such
8710 * that we're serialized against further additions and before
8711 * perf_install_in_context() which is the point the event is active and
8712 * can use these values.
8714 perf_event__header_size(event);
8715 perf_event__id_header_size(event);
8717 perf_install_in_context(ctx, event, event->cpu);
8718 perf_unpin_context(ctx);
8721 mutex_unlock(&gctx->mutex);
8722 mutex_unlock(&ctx->mutex);
8725 mutex_unlock(&task->signal->cred_guard_mutex);
8726 put_task_struct(task);
8731 event->owner = current;
8733 mutex_lock(¤t->perf_event_mutex);
8734 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8735 mutex_unlock(¤t->perf_event_mutex);
8738 * Drop the reference on the group_event after placing the
8739 * new event on the sibling_list. This ensures destruction
8740 * of the group leader will find the pointer to itself in
8741 * perf_group_detach().
8744 fd_install(event_fd, event_file);
8749 mutex_unlock(&gctx->mutex);
8750 mutex_unlock(&ctx->mutex);
8754 perf_unpin_context(ctx);
8758 * If event_file is set, the fput() above will have called ->release()
8759 * and that will take care of freeing the event.
8765 mutex_unlock(&task->signal->cred_guard_mutex);
8770 put_task_struct(task);
8774 put_unused_fd(event_fd);
8779 * perf_event_create_kernel_counter
8781 * @attr: attributes of the counter to create
8782 * @cpu: cpu in which the counter is bound
8783 * @task: task to profile (NULL for percpu)
8786 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8787 struct task_struct *task,
8788 perf_overflow_handler_t overflow_handler,
8791 struct perf_event_context *ctx;
8792 struct perf_event *event;
8796 * Get the target context (task or percpu):
8799 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8800 overflow_handler, context, -1);
8801 if (IS_ERR(event)) {
8802 err = PTR_ERR(event);
8806 /* Mark owner so we could distinguish it from user events. */
8807 event->owner = EVENT_OWNER_KERNEL;
8809 ctx = find_get_context(event->pmu, task, event);
8815 WARN_ON_ONCE(ctx->parent_ctx);
8816 mutex_lock(&ctx->mutex);
8817 if (!exclusive_event_installable(event, ctx)) {
8818 mutex_unlock(&ctx->mutex);
8819 perf_unpin_context(ctx);
8825 perf_install_in_context(ctx, event, cpu);
8826 perf_unpin_context(ctx);
8827 mutex_unlock(&ctx->mutex);
8834 return ERR_PTR(err);
8836 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8838 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8840 struct perf_event_context *src_ctx;
8841 struct perf_event_context *dst_ctx;
8842 struct perf_event *event, *tmp;
8845 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8846 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8849 * See perf_event_ctx_lock() for comments on the details
8850 * of swizzling perf_event::ctx.
8852 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8853 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8855 perf_remove_from_context(event, false);
8856 unaccount_event_cpu(event, src_cpu);
8858 list_add(&event->migrate_entry, &events);
8862 * Wait for the events to quiesce before re-instating them.
8867 * Re-instate events in 2 passes.
8869 * Skip over group leaders and only install siblings on this first
8870 * pass, siblings will not get enabled without a leader, however a
8871 * leader will enable its siblings, even if those are still on the old
8874 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8875 if (event->group_leader == event)
8878 list_del(&event->migrate_entry);
8879 if (event->state >= PERF_EVENT_STATE_OFF)
8880 event->state = PERF_EVENT_STATE_INACTIVE;
8881 account_event_cpu(event, dst_cpu);
8882 perf_install_in_context(dst_ctx, event, dst_cpu);
8887 * Once all the siblings are setup properly, install the group leaders
8890 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8891 list_del(&event->migrate_entry);
8892 if (event->state >= PERF_EVENT_STATE_OFF)
8893 event->state = PERF_EVENT_STATE_INACTIVE;
8894 account_event_cpu(event, dst_cpu);
8895 perf_install_in_context(dst_ctx, event, dst_cpu);
8898 mutex_unlock(&dst_ctx->mutex);
8899 mutex_unlock(&src_ctx->mutex);
8901 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8903 static void sync_child_event(struct perf_event *child_event,
8904 struct task_struct *child)
8906 struct perf_event *parent_event = child_event->parent;
8909 if (child_event->attr.inherit_stat)
8910 perf_event_read_event(child_event, child);
8912 child_val = perf_event_count(child_event);
8915 * Add back the child's count to the parent's count:
8917 atomic64_add(child_val, &parent_event->child_count);
8918 atomic64_add(child_event->total_time_enabled,
8919 &parent_event->child_total_time_enabled);
8920 atomic64_add(child_event->total_time_running,
8921 &parent_event->child_total_time_running);
8924 * Remove this event from the parent's list
8926 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8927 mutex_lock(&parent_event->child_mutex);
8928 list_del_init(&child_event->child_list);
8929 mutex_unlock(&parent_event->child_mutex);
8932 * Make sure user/parent get notified, that we just
8935 perf_event_wakeup(parent_event);
8938 * Release the parent event, if this was the last
8941 put_event(parent_event);
8945 __perf_event_exit_task(struct perf_event *child_event,
8946 struct perf_event_context *child_ctx,
8947 struct task_struct *child)
8950 * Do not destroy the 'original' grouping; because of the context
8951 * switch optimization the original events could've ended up in a
8952 * random child task.
8954 * If we were to destroy the original group, all group related
8955 * operations would cease to function properly after this random
8958 * Do destroy all inherited groups, we don't care about those
8959 * and being thorough is better.
8961 perf_remove_from_context(child_event, !!child_event->parent);
8964 * It can happen that the parent exits first, and has events
8965 * that are still around due to the child reference. These
8966 * events need to be zapped.
8968 if (child_event->parent) {
8969 sync_child_event(child_event, child);
8970 free_event(child_event);
8972 child_event->state = PERF_EVENT_STATE_EXIT;
8973 perf_event_wakeup(child_event);
8977 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8979 struct perf_event *child_event, *next;
8980 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8981 unsigned long flags;
8983 if (likely(!child->perf_event_ctxp[ctxn]))
8986 local_irq_save(flags);
8988 * We can't reschedule here because interrupts are disabled,
8989 * and either child is current or it is a task that can't be
8990 * scheduled, so we are now safe from rescheduling changing
8993 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8996 * Take the context lock here so that if find_get_context is
8997 * reading child->perf_event_ctxp, we wait until it has
8998 * incremented the context's refcount before we do put_ctx below.
9000 raw_spin_lock(&child_ctx->lock);
9001 task_ctx_sched_out(child_ctx);
9002 child->perf_event_ctxp[ctxn] = NULL;
9005 * If this context is a clone; unclone it so it can't get
9006 * swapped to another process while we're removing all
9007 * the events from it.
9009 clone_ctx = unclone_ctx(child_ctx);
9010 update_context_time(child_ctx);
9011 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9017 * Report the task dead after unscheduling the events so that we
9018 * won't get any samples after PERF_RECORD_EXIT. We can however still
9019 * get a few PERF_RECORD_READ events.
9021 perf_event_task(child, child_ctx, 0);
9024 * We can recurse on the same lock type through:
9026 * __perf_event_exit_task()
9027 * sync_child_event()
9029 * mutex_lock(&ctx->mutex)
9031 * But since its the parent context it won't be the same instance.
9033 mutex_lock(&child_ctx->mutex);
9035 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
9036 __perf_event_exit_task(child_event, child_ctx, child);
9038 mutex_unlock(&child_ctx->mutex);
9044 * When a child task exits, feed back event values to parent events.
9046 * Can be called with cred_guard_mutex held when called from
9047 * install_exec_creds().
9049 void perf_event_exit_task(struct task_struct *child)
9051 struct perf_event *event, *tmp;
9054 mutex_lock(&child->perf_event_mutex);
9055 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9057 list_del_init(&event->owner_entry);
9060 * Ensure the list deletion is visible before we clear
9061 * the owner, closes a race against perf_release() where
9062 * we need to serialize on the owner->perf_event_mutex.
9065 event->owner = NULL;
9067 mutex_unlock(&child->perf_event_mutex);
9069 for_each_task_context_nr(ctxn)
9070 perf_event_exit_task_context(child, ctxn);
9073 * The perf_event_exit_task_context calls perf_event_task
9074 * with child's task_ctx, which generates EXIT events for
9075 * child contexts and sets child->perf_event_ctxp[] to NULL.
9076 * At this point we need to send EXIT events to cpu contexts.
9078 perf_event_task(child, NULL, 0);
9081 static void perf_free_event(struct perf_event *event,
9082 struct perf_event_context *ctx)
9084 struct perf_event *parent = event->parent;
9086 if (WARN_ON_ONCE(!parent))
9089 mutex_lock(&parent->child_mutex);
9090 list_del_init(&event->child_list);
9091 mutex_unlock(&parent->child_mutex);
9095 raw_spin_lock_irq(&ctx->lock);
9096 perf_group_detach(event);
9097 list_del_event(event, ctx);
9098 raw_spin_unlock_irq(&ctx->lock);
9103 * Free an unexposed, unused context as created by inheritance by
9104 * perf_event_init_task below, used by fork() in case of fail.
9106 * Not all locks are strictly required, but take them anyway to be nice and
9107 * help out with the lockdep assertions.
9109 void perf_event_free_task(struct task_struct *task)
9111 struct perf_event_context *ctx;
9112 struct perf_event *event, *tmp;
9115 for_each_task_context_nr(ctxn) {
9116 ctx = task->perf_event_ctxp[ctxn];
9120 mutex_lock(&ctx->mutex);
9122 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9124 perf_free_event(event, ctx);
9126 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9128 perf_free_event(event, ctx);
9130 if (!list_empty(&ctx->pinned_groups) ||
9131 !list_empty(&ctx->flexible_groups))
9134 mutex_unlock(&ctx->mutex);
9140 void perf_event_delayed_put(struct task_struct *task)
9144 for_each_task_context_nr(ctxn)
9145 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9148 struct perf_event *perf_event_get(unsigned int fd)
9152 struct perf_event *event;
9154 err = perf_fget_light(fd, &f);
9156 return ERR_PTR(err);
9158 event = f.file->private_data;
9159 atomic_long_inc(&event->refcount);
9165 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9168 return ERR_PTR(-EINVAL);
9170 return &event->attr;
9174 * inherit a event from parent task to child task:
9176 static struct perf_event *
9177 inherit_event(struct perf_event *parent_event,
9178 struct task_struct *parent,
9179 struct perf_event_context *parent_ctx,
9180 struct task_struct *child,
9181 struct perf_event *group_leader,
9182 struct perf_event_context *child_ctx)
9184 enum perf_event_active_state parent_state = parent_event->state;
9185 struct perf_event *child_event;
9186 unsigned long flags;
9189 * Instead of creating recursive hierarchies of events,
9190 * we link inherited events back to the original parent,
9191 * which has a filp for sure, which we use as the reference
9194 if (parent_event->parent)
9195 parent_event = parent_event->parent;
9197 child_event = perf_event_alloc(&parent_event->attr,
9200 group_leader, parent_event,
9202 if (IS_ERR(child_event))
9205 if (is_orphaned_event(parent_event) ||
9206 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9207 free_event(child_event);
9214 * Make the child state follow the state of the parent event,
9215 * not its attr.disabled bit. We hold the parent's mutex,
9216 * so we won't race with perf_event_{en, dis}able_family.
9218 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9219 child_event->state = PERF_EVENT_STATE_INACTIVE;
9221 child_event->state = PERF_EVENT_STATE_OFF;
9223 if (parent_event->attr.freq) {
9224 u64 sample_period = parent_event->hw.sample_period;
9225 struct hw_perf_event *hwc = &child_event->hw;
9227 hwc->sample_period = sample_period;
9228 hwc->last_period = sample_period;
9230 local64_set(&hwc->period_left, sample_period);
9233 child_event->ctx = child_ctx;
9234 child_event->overflow_handler = parent_event->overflow_handler;
9235 child_event->overflow_handler_context
9236 = parent_event->overflow_handler_context;
9239 * Precalculate sample_data sizes
9241 perf_event__header_size(child_event);
9242 perf_event__id_header_size(child_event);
9245 * Link it up in the child's context:
9247 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9248 add_event_to_ctx(child_event, child_ctx);
9249 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9252 * Link this into the parent event's child list
9254 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9255 mutex_lock(&parent_event->child_mutex);
9256 list_add_tail(&child_event->child_list, &parent_event->child_list);
9257 mutex_unlock(&parent_event->child_mutex);
9262 static int inherit_group(struct perf_event *parent_event,
9263 struct task_struct *parent,
9264 struct perf_event_context *parent_ctx,
9265 struct task_struct *child,
9266 struct perf_event_context *child_ctx)
9268 struct perf_event *leader;
9269 struct perf_event *sub;
9270 struct perf_event *child_ctr;
9272 leader = inherit_event(parent_event, parent, parent_ctx,
9273 child, NULL, child_ctx);
9275 return PTR_ERR(leader);
9276 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9277 child_ctr = inherit_event(sub, parent, parent_ctx,
9278 child, leader, child_ctx);
9279 if (IS_ERR(child_ctr))
9280 return PTR_ERR(child_ctr);
9286 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9287 struct perf_event_context *parent_ctx,
9288 struct task_struct *child, int ctxn,
9292 struct perf_event_context *child_ctx;
9294 if (!event->attr.inherit) {
9299 child_ctx = child->perf_event_ctxp[ctxn];
9302 * This is executed from the parent task context, so
9303 * inherit events that have been marked for cloning.
9304 * First allocate and initialize a context for the
9308 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9312 child->perf_event_ctxp[ctxn] = child_ctx;
9315 ret = inherit_group(event, parent, parent_ctx,
9325 * Initialize the perf_event context in task_struct
9327 static int perf_event_init_context(struct task_struct *child, int ctxn)
9329 struct perf_event_context *child_ctx, *parent_ctx;
9330 struct perf_event_context *cloned_ctx;
9331 struct perf_event *event;
9332 struct task_struct *parent = current;
9333 int inherited_all = 1;
9334 unsigned long flags;
9337 if (likely(!parent->perf_event_ctxp[ctxn]))
9341 * If the parent's context is a clone, pin it so it won't get
9344 parent_ctx = perf_pin_task_context(parent, ctxn);
9349 * No need to check if parent_ctx != NULL here; since we saw
9350 * it non-NULL earlier, the only reason for it to become NULL
9351 * is if we exit, and since we're currently in the middle of
9352 * a fork we can't be exiting at the same time.
9356 * Lock the parent list. No need to lock the child - not PID
9357 * hashed yet and not running, so nobody can access it.
9359 mutex_lock(&parent_ctx->mutex);
9362 * We dont have to disable NMIs - we are only looking at
9363 * the list, not manipulating it:
9365 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9366 ret = inherit_task_group(event, parent, parent_ctx,
9367 child, ctxn, &inherited_all);
9373 * We can't hold ctx->lock when iterating the ->flexible_group list due
9374 * to allocations, but we need to prevent rotation because
9375 * rotate_ctx() will change the list from interrupt context.
9377 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9378 parent_ctx->rotate_disable = 1;
9379 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9381 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9382 ret = inherit_task_group(event, parent, parent_ctx,
9383 child, ctxn, &inherited_all);
9388 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9389 parent_ctx->rotate_disable = 0;
9391 child_ctx = child->perf_event_ctxp[ctxn];
9393 if (child_ctx && inherited_all) {
9395 * Mark the child context as a clone of the parent
9396 * context, or of whatever the parent is a clone of.
9398 * Note that if the parent is a clone, the holding of
9399 * parent_ctx->lock avoids it from being uncloned.
9401 cloned_ctx = parent_ctx->parent_ctx;
9403 child_ctx->parent_ctx = cloned_ctx;
9404 child_ctx->parent_gen = parent_ctx->parent_gen;
9406 child_ctx->parent_ctx = parent_ctx;
9407 child_ctx->parent_gen = parent_ctx->generation;
9409 get_ctx(child_ctx->parent_ctx);
9412 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9413 mutex_unlock(&parent_ctx->mutex);
9415 perf_unpin_context(parent_ctx);
9416 put_ctx(parent_ctx);
9422 * Initialize the perf_event context in task_struct
9424 int perf_event_init_task(struct task_struct *child)
9428 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9429 mutex_init(&child->perf_event_mutex);
9430 INIT_LIST_HEAD(&child->perf_event_list);
9432 for_each_task_context_nr(ctxn) {
9433 ret = perf_event_init_context(child, ctxn);
9435 perf_event_free_task(child);
9443 static void __init perf_event_init_all_cpus(void)
9445 struct swevent_htable *swhash;
9448 for_each_possible_cpu(cpu) {
9449 swhash = &per_cpu(swevent_htable, cpu);
9450 mutex_init(&swhash->hlist_mutex);
9451 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9455 static void perf_event_init_cpu(int cpu)
9457 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9459 mutex_lock(&swhash->hlist_mutex);
9460 if (swhash->hlist_refcount > 0) {
9461 struct swevent_hlist *hlist;
9463 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9465 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9467 mutex_unlock(&swhash->hlist_mutex);
9470 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9471 static void __perf_event_exit_context(void *__info)
9473 struct remove_event re = { .detach_group = true };
9474 struct perf_event_context *ctx = __info;
9477 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9478 __perf_remove_from_context(&re);
9482 static void perf_event_exit_cpu_context(int cpu)
9484 struct perf_event_context *ctx;
9488 idx = srcu_read_lock(&pmus_srcu);
9489 list_for_each_entry_rcu(pmu, &pmus, entry) {
9490 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9492 mutex_lock(&ctx->mutex);
9493 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9494 mutex_unlock(&ctx->mutex);
9496 srcu_read_unlock(&pmus_srcu, idx);
9499 static void perf_event_exit_cpu(int cpu)
9501 perf_event_exit_cpu_context(cpu);
9504 static inline void perf_event_exit_cpu(int cpu) { }
9508 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9512 for_each_online_cpu(cpu)
9513 perf_event_exit_cpu(cpu);
9519 * Run the perf reboot notifier at the very last possible moment so that
9520 * the generic watchdog code runs as long as possible.
9522 static struct notifier_block perf_reboot_notifier = {
9523 .notifier_call = perf_reboot,
9524 .priority = INT_MIN,
9528 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9530 unsigned int cpu = (long)hcpu;
9532 switch (action & ~CPU_TASKS_FROZEN) {
9534 case CPU_UP_PREPARE:
9535 case CPU_DOWN_FAILED:
9536 perf_event_init_cpu(cpu);
9539 case CPU_UP_CANCELED:
9540 case CPU_DOWN_PREPARE:
9541 perf_event_exit_cpu(cpu);
9550 void __init perf_event_init(void)
9556 perf_event_init_all_cpus();
9557 init_srcu_struct(&pmus_srcu);
9558 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9559 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9560 perf_pmu_register(&perf_task_clock, NULL, -1);
9562 perf_cpu_notifier(perf_cpu_notify);
9563 register_reboot_notifier(&perf_reboot_notifier);
9565 ret = init_hw_breakpoint();
9566 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9568 /* do not patch jump label more than once per second */
9569 jump_label_rate_limit(&perf_sched_events, HZ);
9572 * Build time assertion that we keep the data_head at the intended
9573 * location. IOW, validation we got the __reserved[] size right.
9575 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9579 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9582 struct perf_pmu_events_attr *pmu_attr =
9583 container_of(attr, struct perf_pmu_events_attr, attr);
9585 if (pmu_attr->event_str)
9586 return sprintf(page, "%s\n", pmu_attr->event_str);
9591 static int __init perf_event_sysfs_init(void)
9596 mutex_lock(&pmus_lock);
9598 ret = bus_register(&pmu_bus);
9602 list_for_each_entry(pmu, &pmus, entry) {
9603 if (!pmu->name || pmu->type < 0)
9606 ret = pmu_dev_alloc(pmu);
9607 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9609 pmu_bus_running = 1;
9613 mutex_unlock(&pmus_lock);
9617 device_initcall(perf_event_sysfs_init);
9619 #ifdef CONFIG_CGROUP_PERF
9620 static struct cgroup_subsys_state *
9621 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9623 struct perf_cgroup *jc;
9625 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9627 return ERR_PTR(-ENOMEM);
9629 jc->info = alloc_percpu(struct perf_cgroup_info);
9632 return ERR_PTR(-ENOMEM);
9638 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9640 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9642 free_percpu(jc->info);
9646 static int __perf_cgroup_move(void *info)
9648 struct task_struct *task = info;
9650 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9655 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9657 struct task_struct *task;
9658 struct cgroup_subsys_state *css;
9660 cgroup_taskset_for_each(task, css, tset)
9661 task_function_call(task, __perf_cgroup_move, task);
9664 struct cgroup_subsys perf_event_cgrp_subsys = {
9665 .css_alloc = perf_cgroup_css_alloc,
9666 .css_free = perf_cgroup_css_free,
9667 .attach = perf_cgroup_attach,
9669 #endif /* CONFIG_CGROUP_PERF */