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 event_filter_match(struct perf_event *event)
1551 return (event->cpu == -1 || event->cpu == smp_processor_id())
1552 && perf_cgroup_match(event) && pmu_filter_match(event);
1556 event_sched_out(struct perf_event *event,
1557 struct perf_cpu_context *cpuctx,
1558 struct perf_event_context *ctx)
1560 u64 tstamp = perf_event_time(event);
1563 WARN_ON_ONCE(event->ctx != ctx);
1564 lockdep_assert_held(&ctx->lock);
1567 * An event which could not be activated because of
1568 * filter mismatch still needs to have its timings
1569 * maintained, otherwise bogus information is return
1570 * via read() for time_enabled, time_running:
1572 if (event->state == PERF_EVENT_STATE_INACTIVE
1573 && !event_filter_match(event)) {
1574 delta = tstamp - event->tstamp_stopped;
1575 event->tstamp_running += delta;
1576 event->tstamp_stopped = tstamp;
1579 if (event->state != PERF_EVENT_STATE_ACTIVE)
1582 perf_pmu_disable(event->pmu);
1584 event->tstamp_stopped = tstamp;
1585 event->pmu->del(event, 0);
1587 event->state = PERF_EVENT_STATE_INACTIVE;
1588 if (event->pending_disable) {
1589 event->pending_disable = 0;
1590 event->state = PERF_EVENT_STATE_OFF;
1593 if (!is_software_event(event))
1594 cpuctx->active_oncpu--;
1595 if (!--ctx->nr_active)
1596 perf_event_ctx_deactivate(ctx);
1597 if (event->attr.freq && event->attr.sample_freq)
1599 if (event->attr.exclusive || !cpuctx->active_oncpu)
1600 cpuctx->exclusive = 0;
1602 if (is_orphaned_child(event))
1603 schedule_orphans_remove(ctx);
1605 perf_pmu_enable(event->pmu);
1609 group_sched_out(struct perf_event *group_event,
1610 struct perf_cpu_context *cpuctx,
1611 struct perf_event_context *ctx)
1613 struct perf_event *event;
1614 int state = group_event->state;
1616 event_sched_out(group_event, cpuctx, ctx);
1619 * Schedule out siblings (if any):
1621 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1622 event_sched_out(event, cpuctx, ctx);
1624 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1625 cpuctx->exclusive = 0;
1628 struct remove_event {
1629 struct perf_event *event;
1634 * Cross CPU call to remove a performance event
1636 * We disable the event on the hardware level first. After that we
1637 * remove it from the context list.
1639 static int __perf_remove_from_context(void *info)
1641 struct remove_event *re = info;
1642 struct perf_event *event = re->event;
1643 struct perf_event_context *ctx = event->ctx;
1644 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1646 raw_spin_lock(&ctx->lock);
1647 event_sched_out(event, cpuctx, ctx);
1648 if (re->detach_group)
1649 perf_group_detach(event);
1650 list_del_event(event, ctx);
1651 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1653 cpuctx->task_ctx = NULL;
1655 raw_spin_unlock(&ctx->lock);
1662 * Remove the event from a task's (or a CPU's) list of events.
1664 * CPU events are removed with a smp call. For task events we only
1665 * call when the task is on a CPU.
1667 * If event->ctx is a cloned context, callers must make sure that
1668 * every task struct that event->ctx->task could possibly point to
1669 * remains valid. This is OK when called from perf_release since
1670 * that only calls us on the top-level context, which can't be a clone.
1671 * When called from perf_event_exit_task, it's OK because the
1672 * context has been detached from its task.
1674 static void perf_remove_from_context(struct perf_event *event, bool detach_group)
1676 struct perf_event_context *ctx = event->ctx;
1677 struct task_struct *task = ctx->task;
1678 struct remove_event re = {
1680 .detach_group = detach_group,
1683 lockdep_assert_held(&ctx->mutex);
1687 * Per cpu events are removed via an smp call. The removal can
1688 * fail if the CPU is currently offline, but in that case we
1689 * already called __perf_remove_from_context from
1690 * perf_event_exit_cpu.
1692 cpu_function_call(event->cpu, __perf_remove_from_context, &re);
1697 if (!task_function_call(task, __perf_remove_from_context, &re))
1700 raw_spin_lock_irq(&ctx->lock);
1702 * If we failed to find a running task, but find the context active now
1703 * that we've acquired the ctx->lock, retry.
1705 if (ctx->is_active) {
1706 raw_spin_unlock_irq(&ctx->lock);
1708 * Reload the task pointer, it might have been changed by
1709 * a concurrent perf_event_context_sched_out().
1716 * Since the task isn't running, its safe to remove the event, us
1717 * holding the ctx->lock ensures the task won't get scheduled in.
1720 perf_group_detach(event);
1721 list_del_event(event, ctx);
1722 raw_spin_unlock_irq(&ctx->lock);
1726 * Cross CPU call to disable a performance event
1728 int __perf_event_disable(void *info)
1730 struct perf_event *event = info;
1731 struct perf_event_context *ctx = event->ctx;
1732 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1735 * If this is a per-task event, need to check whether this
1736 * event's task is the current task on this cpu.
1738 * Can trigger due to concurrent perf_event_context_sched_out()
1739 * flipping contexts around.
1741 if (ctx->task && cpuctx->task_ctx != ctx)
1744 raw_spin_lock(&ctx->lock);
1747 * If the event is on, turn it off.
1748 * If it is in error state, leave it in error state.
1750 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1751 update_context_time(ctx);
1752 update_cgrp_time_from_event(event);
1753 update_group_times(event);
1754 if (event == event->group_leader)
1755 group_sched_out(event, cpuctx, ctx);
1757 event_sched_out(event, cpuctx, ctx);
1758 event->state = PERF_EVENT_STATE_OFF;
1761 raw_spin_unlock(&ctx->lock);
1769 * If event->ctx is a cloned context, callers must make sure that
1770 * every task struct that event->ctx->task could possibly point to
1771 * remains valid. This condition is satisifed when called through
1772 * perf_event_for_each_child or perf_event_for_each because they
1773 * hold the top-level event's child_mutex, so any descendant that
1774 * goes to exit will block in sync_child_event.
1775 * When called from perf_pending_event it's OK because event->ctx
1776 * is the current context on this CPU and preemption is disabled,
1777 * hence we can't get into perf_event_task_sched_out for this context.
1779 static void _perf_event_disable(struct perf_event *event)
1781 struct perf_event_context *ctx = event->ctx;
1782 struct task_struct *task = ctx->task;
1786 * Disable the event on the cpu that it's on
1788 cpu_function_call(event->cpu, __perf_event_disable, event);
1793 if (!task_function_call(task, __perf_event_disable, event))
1796 raw_spin_lock_irq(&ctx->lock);
1798 * If the event is still active, we need to retry the cross-call.
1800 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1801 raw_spin_unlock_irq(&ctx->lock);
1803 * Reload the task pointer, it might have been changed by
1804 * a concurrent perf_event_context_sched_out().
1811 * Since we have the lock this context can't be scheduled
1812 * in, so we can change the state safely.
1814 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1815 update_group_times(event);
1816 event->state = PERF_EVENT_STATE_OFF;
1818 raw_spin_unlock_irq(&ctx->lock);
1822 * Strictly speaking kernel users cannot create groups and therefore this
1823 * interface does not need the perf_event_ctx_lock() magic.
1825 void perf_event_disable(struct perf_event *event)
1827 struct perf_event_context *ctx;
1829 ctx = perf_event_ctx_lock(event);
1830 _perf_event_disable(event);
1831 perf_event_ctx_unlock(event, ctx);
1833 EXPORT_SYMBOL_GPL(perf_event_disable);
1835 static void perf_set_shadow_time(struct perf_event *event,
1836 struct perf_event_context *ctx,
1840 * use the correct time source for the time snapshot
1842 * We could get by without this by leveraging the
1843 * fact that to get to this function, the caller
1844 * has most likely already called update_context_time()
1845 * and update_cgrp_time_xx() and thus both timestamp
1846 * are identical (or very close). Given that tstamp is,
1847 * already adjusted for cgroup, we could say that:
1848 * tstamp - ctx->timestamp
1850 * tstamp - cgrp->timestamp.
1852 * Then, in perf_output_read(), the calculation would
1853 * work with no changes because:
1854 * - event is guaranteed scheduled in
1855 * - no scheduled out in between
1856 * - thus the timestamp would be the same
1858 * But this is a bit hairy.
1860 * So instead, we have an explicit cgroup call to remain
1861 * within the time time source all along. We believe it
1862 * is cleaner and simpler to understand.
1864 if (is_cgroup_event(event))
1865 perf_cgroup_set_shadow_time(event, tstamp);
1867 event->shadow_ctx_time = tstamp - ctx->timestamp;
1870 #define MAX_INTERRUPTS (~0ULL)
1872 static void perf_log_throttle(struct perf_event *event, int enable);
1873 static void perf_log_itrace_start(struct perf_event *event);
1876 event_sched_in(struct perf_event *event,
1877 struct perf_cpu_context *cpuctx,
1878 struct perf_event_context *ctx)
1880 u64 tstamp = perf_event_time(event);
1883 lockdep_assert_held(&ctx->lock);
1885 if (event->state <= PERF_EVENT_STATE_OFF)
1888 event->state = PERF_EVENT_STATE_ACTIVE;
1889 event->oncpu = smp_processor_id();
1892 * Unthrottle events, since we scheduled we might have missed several
1893 * ticks already, also for a heavily scheduling task there is little
1894 * guarantee it'll get a tick in a timely manner.
1896 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1897 perf_log_throttle(event, 1);
1898 event->hw.interrupts = 0;
1902 * The new state must be visible before we turn it on in the hardware:
1906 perf_pmu_disable(event->pmu);
1908 perf_set_shadow_time(event, ctx, tstamp);
1910 perf_log_itrace_start(event);
1912 if (event->pmu->add(event, PERF_EF_START)) {
1913 event->state = PERF_EVENT_STATE_INACTIVE;
1919 event->tstamp_running += tstamp - event->tstamp_stopped;
1921 if (!is_software_event(event))
1922 cpuctx->active_oncpu++;
1923 if (!ctx->nr_active++)
1924 perf_event_ctx_activate(ctx);
1925 if (event->attr.freq && event->attr.sample_freq)
1928 if (event->attr.exclusive)
1929 cpuctx->exclusive = 1;
1931 if (is_orphaned_child(event))
1932 schedule_orphans_remove(ctx);
1935 perf_pmu_enable(event->pmu);
1941 group_sched_in(struct perf_event *group_event,
1942 struct perf_cpu_context *cpuctx,
1943 struct perf_event_context *ctx)
1945 struct perf_event *event, *partial_group = NULL;
1946 struct pmu *pmu = ctx->pmu;
1947 u64 now = ctx->time;
1948 bool simulate = false;
1950 if (group_event->state == PERF_EVENT_STATE_OFF)
1953 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1955 if (event_sched_in(group_event, cpuctx, ctx)) {
1956 pmu->cancel_txn(pmu);
1957 perf_mux_hrtimer_restart(cpuctx);
1962 * Schedule in siblings as one group (if any):
1964 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1965 if (event_sched_in(event, cpuctx, ctx)) {
1966 partial_group = event;
1971 if (!pmu->commit_txn(pmu))
1976 * Groups can be scheduled in as one unit only, so undo any
1977 * partial group before returning:
1978 * The events up to the failed event are scheduled out normally,
1979 * tstamp_stopped will be updated.
1981 * The failed events and the remaining siblings need to have
1982 * their timings updated as if they had gone thru event_sched_in()
1983 * and event_sched_out(). This is required to get consistent timings
1984 * across the group. This also takes care of the case where the group
1985 * could never be scheduled by ensuring tstamp_stopped is set to mark
1986 * the time the event was actually stopped, such that time delta
1987 * calculation in update_event_times() is correct.
1989 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1990 if (event == partial_group)
1994 event->tstamp_running += now - event->tstamp_stopped;
1995 event->tstamp_stopped = now;
1997 event_sched_out(event, cpuctx, ctx);
2000 event_sched_out(group_event, cpuctx, ctx);
2002 pmu->cancel_txn(pmu);
2004 perf_mux_hrtimer_restart(cpuctx);
2010 * Work out whether we can put this event group on the CPU now.
2012 static int group_can_go_on(struct perf_event *event,
2013 struct perf_cpu_context *cpuctx,
2017 * Groups consisting entirely of software events can always go on.
2019 if (event->group_flags & PERF_GROUP_SOFTWARE)
2022 * If an exclusive group is already on, no other hardware
2025 if (cpuctx->exclusive)
2028 * If this group is exclusive and there are already
2029 * events on the CPU, it can't go on.
2031 if (event->attr.exclusive && cpuctx->active_oncpu)
2034 * Otherwise, try to add it if all previous groups were able
2040 static void add_event_to_ctx(struct perf_event *event,
2041 struct perf_event_context *ctx)
2043 u64 tstamp = perf_event_time(event);
2045 list_add_event(event, ctx);
2046 perf_group_attach(event);
2047 event->tstamp_enabled = tstamp;
2048 event->tstamp_running = tstamp;
2049 event->tstamp_stopped = tstamp;
2052 static void task_ctx_sched_out(struct perf_event_context *ctx);
2054 ctx_sched_in(struct perf_event_context *ctx,
2055 struct perf_cpu_context *cpuctx,
2056 enum event_type_t event_type,
2057 struct task_struct *task);
2059 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2060 struct perf_event_context *ctx,
2061 struct task_struct *task)
2063 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2065 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2066 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2068 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2072 * Cross CPU call to install and enable a performance event
2074 * Must be called with ctx->mutex held
2076 static int __perf_install_in_context(void *info)
2078 struct perf_event *event = info;
2079 struct perf_event_context *ctx = event->ctx;
2080 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2081 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2082 struct task_struct *task = current;
2084 perf_ctx_lock(cpuctx, task_ctx);
2085 perf_pmu_disable(cpuctx->ctx.pmu);
2088 * If there was an active task_ctx schedule it out.
2091 task_ctx_sched_out(task_ctx);
2094 * If the context we're installing events in is not the
2095 * active task_ctx, flip them.
2097 if (ctx->task && task_ctx != ctx) {
2099 raw_spin_unlock(&task_ctx->lock);
2100 raw_spin_lock(&ctx->lock);
2105 cpuctx->task_ctx = task_ctx;
2106 task = task_ctx->task;
2109 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2111 update_context_time(ctx);
2113 * update cgrp time only if current cgrp
2114 * matches event->cgrp. Must be done before
2115 * calling add_event_to_ctx()
2117 update_cgrp_time_from_event(event);
2119 add_event_to_ctx(event, ctx);
2122 * Schedule everything back in
2124 perf_event_sched_in(cpuctx, task_ctx, task);
2126 perf_pmu_enable(cpuctx->ctx.pmu);
2127 perf_ctx_unlock(cpuctx, task_ctx);
2133 * Attach a performance event to a context
2135 * First we add the event to the list with the hardware enable bit
2136 * in event->hw_config cleared.
2138 * If the event is attached to a task which is on a CPU we use a smp
2139 * call to enable it in the task context. The task might have been
2140 * scheduled away, but we check this in the smp call again.
2143 perf_install_in_context(struct perf_event_context *ctx,
2144 struct perf_event *event,
2147 struct task_struct *task = ctx->task;
2149 lockdep_assert_held(&ctx->mutex);
2152 if (event->cpu != -1)
2157 * Per cpu events are installed via an smp call and
2158 * the install is always successful.
2160 cpu_function_call(cpu, __perf_install_in_context, event);
2165 if (!task_function_call(task, __perf_install_in_context, event))
2168 raw_spin_lock_irq(&ctx->lock);
2170 * If we failed to find a running task, but find the context active now
2171 * that we've acquired the ctx->lock, retry.
2173 if (ctx->is_active) {
2174 raw_spin_unlock_irq(&ctx->lock);
2176 * Reload the task pointer, it might have been changed by
2177 * a concurrent perf_event_context_sched_out().
2184 * Since the task isn't running, its safe to add the event, us holding
2185 * the ctx->lock ensures the task won't get scheduled in.
2187 add_event_to_ctx(event, ctx);
2188 raw_spin_unlock_irq(&ctx->lock);
2192 * Put a event into inactive state and update time fields.
2193 * Enabling the leader of a group effectively enables all
2194 * the group members that aren't explicitly disabled, so we
2195 * have to update their ->tstamp_enabled also.
2196 * Note: this works for group members as well as group leaders
2197 * since the non-leader members' sibling_lists will be empty.
2199 static void __perf_event_mark_enabled(struct perf_event *event)
2201 struct perf_event *sub;
2202 u64 tstamp = perf_event_time(event);
2204 event->state = PERF_EVENT_STATE_INACTIVE;
2205 event->tstamp_enabled = tstamp - event->total_time_enabled;
2206 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2207 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2208 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2213 * Cross CPU call to enable a performance event
2215 static int __perf_event_enable(void *info)
2217 struct perf_event *event = info;
2218 struct perf_event_context *ctx = event->ctx;
2219 struct perf_event *leader = event->group_leader;
2220 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2224 * There's a time window between 'ctx->is_active' check
2225 * in perf_event_enable function and this place having:
2227 * - ctx->lock unlocked
2229 * where the task could be killed and 'ctx' deactivated
2230 * by perf_event_exit_task.
2232 if (!ctx->is_active)
2235 raw_spin_lock(&ctx->lock);
2236 update_context_time(ctx);
2238 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2242 * set current task's cgroup time reference point
2244 perf_cgroup_set_timestamp(current, ctx);
2246 __perf_event_mark_enabled(event);
2248 if (!event_filter_match(event)) {
2249 if (is_cgroup_event(event))
2250 perf_cgroup_defer_enabled(event);
2255 * If the event is in a group and isn't the group leader,
2256 * then don't put it on unless the group is on.
2258 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2261 if (!group_can_go_on(event, cpuctx, 1)) {
2264 if (event == leader)
2265 err = group_sched_in(event, cpuctx, ctx);
2267 err = event_sched_in(event, cpuctx, ctx);
2272 * If this event can't go on and it's part of a
2273 * group, then the whole group has to come off.
2275 if (leader != event) {
2276 group_sched_out(leader, cpuctx, ctx);
2277 perf_mux_hrtimer_restart(cpuctx);
2279 if (leader->attr.pinned) {
2280 update_group_times(leader);
2281 leader->state = PERF_EVENT_STATE_ERROR;
2286 raw_spin_unlock(&ctx->lock);
2294 * If event->ctx is a cloned context, callers must make sure that
2295 * every task struct that event->ctx->task could possibly point to
2296 * remains valid. This condition is satisfied when called through
2297 * perf_event_for_each_child or perf_event_for_each as described
2298 * for perf_event_disable.
2300 static void _perf_event_enable(struct perf_event *event)
2302 struct perf_event_context *ctx = event->ctx;
2303 struct task_struct *task = ctx->task;
2307 * Enable the event on the cpu that it's on
2309 cpu_function_call(event->cpu, __perf_event_enable, event);
2313 raw_spin_lock_irq(&ctx->lock);
2314 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2318 * If the event is in error state, clear that first.
2319 * That way, if we see the event in error state below, we
2320 * know that it has gone back into error state, as distinct
2321 * from the task having been scheduled away before the
2322 * cross-call arrived.
2324 if (event->state == PERF_EVENT_STATE_ERROR)
2325 event->state = PERF_EVENT_STATE_OFF;
2328 if (!ctx->is_active) {
2329 __perf_event_mark_enabled(event);
2333 raw_spin_unlock_irq(&ctx->lock);
2335 if (!task_function_call(task, __perf_event_enable, event))
2338 raw_spin_lock_irq(&ctx->lock);
2341 * If the context is active and the event is still off,
2342 * we need to retry the cross-call.
2344 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2346 * task could have been flipped by a concurrent
2347 * perf_event_context_sched_out()
2354 raw_spin_unlock_irq(&ctx->lock);
2358 * See perf_event_disable();
2360 void perf_event_enable(struct perf_event *event)
2362 struct perf_event_context *ctx;
2364 ctx = perf_event_ctx_lock(event);
2365 _perf_event_enable(event);
2366 perf_event_ctx_unlock(event, ctx);
2368 EXPORT_SYMBOL_GPL(perf_event_enable);
2370 static int _perf_event_refresh(struct perf_event *event, int refresh)
2373 * not supported on inherited events
2375 if (event->attr.inherit || !is_sampling_event(event))
2378 atomic_add(refresh, &event->event_limit);
2379 _perf_event_enable(event);
2385 * See perf_event_disable()
2387 int perf_event_refresh(struct perf_event *event, int refresh)
2389 struct perf_event_context *ctx;
2392 ctx = perf_event_ctx_lock(event);
2393 ret = _perf_event_refresh(event, refresh);
2394 perf_event_ctx_unlock(event, ctx);
2398 EXPORT_SYMBOL_GPL(perf_event_refresh);
2400 static void ctx_sched_out(struct perf_event_context *ctx,
2401 struct perf_cpu_context *cpuctx,
2402 enum event_type_t event_type)
2404 struct perf_event *event;
2405 int is_active = ctx->is_active;
2407 ctx->is_active &= ~event_type;
2408 if (likely(!ctx->nr_events))
2411 update_context_time(ctx);
2412 update_cgrp_time_from_cpuctx(cpuctx);
2413 if (!ctx->nr_active)
2416 perf_pmu_disable(ctx->pmu);
2417 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2418 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2419 group_sched_out(event, cpuctx, ctx);
2422 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2423 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2424 group_sched_out(event, cpuctx, ctx);
2426 perf_pmu_enable(ctx->pmu);
2430 * Test whether two contexts are equivalent, i.e. whether they have both been
2431 * cloned from the same version of the same context.
2433 * Equivalence is measured using a generation number in the context that is
2434 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2435 * and list_del_event().
2437 static int context_equiv(struct perf_event_context *ctx1,
2438 struct perf_event_context *ctx2)
2440 lockdep_assert_held(&ctx1->lock);
2441 lockdep_assert_held(&ctx2->lock);
2443 /* Pinning disables the swap optimization */
2444 if (ctx1->pin_count || ctx2->pin_count)
2447 /* If ctx1 is the parent of ctx2 */
2448 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2451 /* If ctx2 is the parent of ctx1 */
2452 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2456 * If ctx1 and ctx2 have the same parent; we flatten the parent
2457 * hierarchy, see perf_event_init_context().
2459 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2460 ctx1->parent_gen == ctx2->parent_gen)
2467 static void __perf_event_sync_stat(struct perf_event *event,
2468 struct perf_event *next_event)
2472 if (!event->attr.inherit_stat)
2476 * Update the event value, we cannot use perf_event_read()
2477 * because we're in the middle of a context switch and have IRQs
2478 * disabled, which upsets smp_call_function_single(), however
2479 * we know the event must be on the current CPU, therefore we
2480 * don't need to use it.
2482 switch (event->state) {
2483 case PERF_EVENT_STATE_ACTIVE:
2484 event->pmu->read(event);
2487 case PERF_EVENT_STATE_INACTIVE:
2488 update_event_times(event);
2496 * In order to keep per-task stats reliable we need to flip the event
2497 * values when we flip the contexts.
2499 value = local64_read(&next_event->count);
2500 value = local64_xchg(&event->count, value);
2501 local64_set(&next_event->count, value);
2503 swap(event->total_time_enabled, next_event->total_time_enabled);
2504 swap(event->total_time_running, next_event->total_time_running);
2507 * Since we swizzled the values, update the user visible data too.
2509 perf_event_update_userpage(event);
2510 perf_event_update_userpage(next_event);
2513 static void perf_event_sync_stat(struct perf_event_context *ctx,
2514 struct perf_event_context *next_ctx)
2516 struct perf_event *event, *next_event;
2521 update_context_time(ctx);
2523 event = list_first_entry(&ctx->event_list,
2524 struct perf_event, event_entry);
2526 next_event = list_first_entry(&next_ctx->event_list,
2527 struct perf_event, event_entry);
2529 while (&event->event_entry != &ctx->event_list &&
2530 &next_event->event_entry != &next_ctx->event_list) {
2532 __perf_event_sync_stat(event, next_event);
2534 event = list_next_entry(event, event_entry);
2535 next_event = list_next_entry(next_event, event_entry);
2539 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2540 struct task_struct *next)
2542 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2543 struct perf_event_context *next_ctx;
2544 struct perf_event_context *parent, *next_parent;
2545 struct perf_cpu_context *cpuctx;
2551 cpuctx = __get_cpu_context(ctx);
2552 if (!cpuctx->task_ctx)
2556 next_ctx = next->perf_event_ctxp[ctxn];
2560 parent = rcu_dereference(ctx->parent_ctx);
2561 next_parent = rcu_dereference(next_ctx->parent_ctx);
2563 /* If neither context have a parent context; they cannot be clones. */
2564 if (!parent && !next_parent)
2567 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2569 * Looks like the two contexts are clones, so we might be
2570 * able to optimize the context switch. We lock both
2571 * contexts and check that they are clones under the
2572 * lock (including re-checking that neither has been
2573 * uncloned in the meantime). It doesn't matter which
2574 * order we take the locks because no other cpu could
2575 * be trying to lock both of these tasks.
2577 raw_spin_lock(&ctx->lock);
2578 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2579 if (context_equiv(ctx, next_ctx)) {
2581 * XXX do we need a memory barrier of sorts
2582 * wrt to rcu_dereference() of perf_event_ctxp
2584 task->perf_event_ctxp[ctxn] = next_ctx;
2585 next->perf_event_ctxp[ctxn] = ctx;
2587 next_ctx->task = task;
2589 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2593 perf_event_sync_stat(ctx, next_ctx);
2595 raw_spin_unlock(&next_ctx->lock);
2596 raw_spin_unlock(&ctx->lock);
2602 raw_spin_lock(&ctx->lock);
2603 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2604 cpuctx->task_ctx = NULL;
2605 raw_spin_unlock(&ctx->lock);
2609 void perf_sched_cb_dec(struct pmu *pmu)
2611 this_cpu_dec(perf_sched_cb_usages);
2614 void perf_sched_cb_inc(struct pmu *pmu)
2616 this_cpu_inc(perf_sched_cb_usages);
2620 * This function provides the context switch callback to the lower code
2621 * layer. It is invoked ONLY when the context switch callback is enabled.
2623 static void perf_pmu_sched_task(struct task_struct *prev,
2624 struct task_struct *next,
2627 struct perf_cpu_context *cpuctx;
2629 unsigned long flags;
2634 local_irq_save(flags);
2638 list_for_each_entry_rcu(pmu, &pmus, entry) {
2639 if (pmu->sched_task) {
2640 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2642 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2644 perf_pmu_disable(pmu);
2646 pmu->sched_task(cpuctx->task_ctx, sched_in);
2648 perf_pmu_enable(pmu);
2650 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2656 local_irq_restore(flags);
2659 static void perf_event_switch(struct task_struct *task,
2660 struct task_struct *next_prev, bool sched_in);
2662 #define for_each_task_context_nr(ctxn) \
2663 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2666 * Called from scheduler to remove the events of the current task,
2667 * with interrupts disabled.
2669 * We stop each event and update the event value in event->count.
2671 * This does not protect us against NMI, but disable()
2672 * sets the disabled bit in the control field of event _before_
2673 * accessing the event control register. If a NMI hits, then it will
2674 * not restart the event.
2676 void __perf_event_task_sched_out(struct task_struct *task,
2677 struct task_struct *next)
2681 if (__this_cpu_read(perf_sched_cb_usages))
2682 perf_pmu_sched_task(task, next, false);
2684 if (atomic_read(&nr_switch_events))
2685 perf_event_switch(task, next, false);
2687 for_each_task_context_nr(ctxn)
2688 perf_event_context_sched_out(task, ctxn, next);
2691 * if cgroup events exist on this CPU, then we need
2692 * to check if we have to switch out PMU state.
2693 * cgroup event are system-wide mode only
2695 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2696 perf_cgroup_sched_out(task, next);
2699 static void task_ctx_sched_out(struct perf_event_context *ctx)
2701 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2703 if (!cpuctx->task_ctx)
2706 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2709 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2710 cpuctx->task_ctx = NULL;
2714 * Called with IRQs disabled
2716 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2717 enum event_type_t event_type)
2719 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2723 ctx_pinned_sched_in(struct perf_event_context *ctx,
2724 struct perf_cpu_context *cpuctx)
2726 struct perf_event *event;
2728 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2729 if (event->state <= PERF_EVENT_STATE_OFF)
2731 if (!event_filter_match(event))
2734 /* may need to reset tstamp_enabled */
2735 if (is_cgroup_event(event))
2736 perf_cgroup_mark_enabled(event, ctx);
2738 if (group_can_go_on(event, cpuctx, 1))
2739 group_sched_in(event, cpuctx, ctx);
2742 * If this pinned group hasn't been scheduled,
2743 * put it in error state.
2745 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2746 update_group_times(event);
2747 event->state = PERF_EVENT_STATE_ERROR;
2753 ctx_flexible_sched_in(struct perf_event_context *ctx,
2754 struct perf_cpu_context *cpuctx)
2756 struct perf_event *event;
2759 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2760 /* Ignore events in OFF or ERROR state */
2761 if (event->state <= PERF_EVENT_STATE_OFF)
2764 * Listen to the 'cpu' scheduling filter constraint
2767 if (!event_filter_match(event))
2770 /* may need to reset tstamp_enabled */
2771 if (is_cgroup_event(event))
2772 perf_cgroup_mark_enabled(event, ctx);
2774 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2775 if (group_sched_in(event, cpuctx, ctx))
2782 ctx_sched_in(struct perf_event_context *ctx,
2783 struct perf_cpu_context *cpuctx,
2784 enum event_type_t event_type,
2785 struct task_struct *task)
2788 int is_active = ctx->is_active;
2790 ctx->is_active |= event_type;
2791 if (likely(!ctx->nr_events))
2795 ctx->timestamp = now;
2796 perf_cgroup_set_timestamp(task, ctx);
2798 * First go through the list and put on any pinned groups
2799 * in order to give them the best chance of going on.
2801 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2802 ctx_pinned_sched_in(ctx, cpuctx);
2804 /* Then walk through the lower prio flexible groups */
2805 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2806 ctx_flexible_sched_in(ctx, cpuctx);
2809 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2810 enum event_type_t event_type,
2811 struct task_struct *task)
2813 struct perf_event_context *ctx = &cpuctx->ctx;
2815 ctx_sched_in(ctx, cpuctx, event_type, task);
2818 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2819 struct task_struct *task)
2821 struct perf_cpu_context *cpuctx;
2823 cpuctx = __get_cpu_context(ctx);
2824 if (cpuctx->task_ctx == ctx)
2827 perf_ctx_lock(cpuctx, ctx);
2828 perf_pmu_disable(ctx->pmu);
2830 * We want to keep the following priority order:
2831 * cpu pinned (that don't need to move), task pinned,
2832 * cpu flexible, task flexible.
2834 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2837 cpuctx->task_ctx = ctx;
2839 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2841 perf_pmu_enable(ctx->pmu);
2842 perf_ctx_unlock(cpuctx, ctx);
2846 * Called from scheduler to add the events of the current task
2847 * with interrupts disabled.
2849 * We restore the event value and then enable it.
2851 * This does not protect us against NMI, but enable()
2852 * sets the enabled bit in the control field of event _before_
2853 * accessing the event control register. If a NMI hits, then it will
2854 * keep the event running.
2856 void __perf_event_task_sched_in(struct task_struct *prev,
2857 struct task_struct *task)
2859 struct perf_event_context *ctx;
2862 for_each_task_context_nr(ctxn) {
2863 ctx = task->perf_event_ctxp[ctxn];
2867 perf_event_context_sched_in(ctx, task);
2870 * if cgroup events exist on this CPU, then we need
2871 * to check if we have to switch in PMU state.
2872 * cgroup event are system-wide mode only
2874 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2875 perf_cgroup_sched_in(prev, task);
2877 if (atomic_read(&nr_switch_events))
2878 perf_event_switch(task, prev, true);
2880 if (__this_cpu_read(perf_sched_cb_usages))
2881 perf_pmu_sched_task(prev, task, true);
2884 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2886 u64 frequency = event->attr.sample_freq;
2887 u64 sec = NSEC_PER_SEC;
2888 u64 divisor, dividend;
2890 int count_fls, nsec_fls, frequency_fls, sec_fls;
2892 count_fls = fls64(count);
2893 nsec_fls = fls64(nsec);
2894 frequency_fls = fls64(frequency);
2898 * We got @count in @nsec, with a target of sample_freq HZ
2899 * the target period becomes:
2902 * period = -------------------
2903 * @nsec * sample_freq
2908 * Reduce accuracy by one bit such that @a and @b converge
2909 * to a similar magnitude.
2911 #define REDUCE_FLS(a, b) \
2913 if (a##_fls > b##_fls) { \
2923 * Reduce accuracy until either term fits in a u64, then proceed with
2924 * the other, so that finally we can do a u64/u64 division.
2926 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2927 REDUCE_FLS(nsec, frequency);
2928 REDUCE_FLS(sec, count);
2931 if (count_fls + sec_fls > 64) {
2932 divisor = nsec * frequency;
2934 while (count_fls + sec_fls > 64) {
2935 REDUCE_FLS(count, sec);
2939 dividend = count * sec;
2941 dividend = count * sec;
2943 while (nsec_fls + frequency_fls > 64) {
2944 REDUCE_FLS(nsec, frequency);
2948 divisor = nsec * frequency;
2954 return div64_u64(dividend, divisor);
2957 static DEFINE_PER_CPU(int, perf_throttled_count);
2958 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2960 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2962 struct hw_perf_event *hwc = &event->hw;
2963 s64 period, sample_period;
2966 period = perf_calculate_period(event, nsec, count);
2968 delta = (s64)(period - hwc->sample_period);
2969 delta = (delta + 7) / 8; /* low pass filter */
2971 sample_period = hwc->sample_period + delta;
2976 hwc->sample_period = sample_period;
2978 if (local64_read(&hwc->period_left) > 8*sample_period) {
2980 event->pmu->stop(event, PERF_EF_UPDATE);
2982 local64_set(&hwc->period_left, 0);
2985 event->pmu->start(event, PERF_EF_RELOAD);
2990 * combine freq adjustment with unthrottling to avoid two passes over the
2991 * events. At the same time, make sure, having freq events does not change
2992 * the rate of unthrottling as that would introduce bias.
2994 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2997 struct perf_event *event;
2998 struct hw_perf_event *hwc;
2999 u64 now, period = TICK_NSEC;
3003 * only need to iterate over all events iff:
3004 * - context have events in frequency mode (needs freq adjust)
3005 * - there are events to unthrottle on this cpu
3007 if (!(ctx->nr_freq || needs_unthr))
3010 raw_spin_lock(&ctx->lock);
3011 perf_pmu_disable(ctx->pmu);
3013 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3014 if (event->state != PERF_EVENT_STATE_ACTIVE)
3017 if (!event_filter_match(event))
3020 perf_pmu_disable(event->pmu);
3024 if (hwc->interrupts == MAX_INTERRUPTS) {
3025 hwc->interrupts = 0;
3026 perf_log_throttle(event, 1);
3027 event->pmu->start(event, 0);
3030 if (!event->attr.freq || !event->attr.sample_freq)
3034 * stop the event and update event->count
3036 event->pmu->stop(event, PERF_EF_UPDATE);
3038 now = local64_read(&event->count);
3039 delta = now - hwc->freq_count_stamp;
3040 hwc->freq_count_stamp = now;
3044 * reload only if value has changed
3045 * we have stopped the event so tell that
3046 * to perf_adjust_period() to avoid stopping it
3050 perf_adjust_period(event, period, delta, false);
3052 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3054 perf_pmu_enable(event->pmu);
3057 perf_pmu_enable(ctx->pmu);
3058 raw_spin_unlock(&ctx->lock);
3062 * Round-robin a context's events:
3064 static void rotate_ctx(struct perf_event_context *ctx)
3067 * Rotate the first entry last of non-pinned groups. Rotation might be
3068 * disabled by the inheritance code.
3070 if (!ctx->rotate_disable)
3071 list_rotate_left(&ctx->flexible_groups);
3074 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3076 struct perf_event_context *ctx = NULL;
3079 if (cpuctx->ctx.nr_events) {
3080 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3084 ctx = cpuctx->task_ctx;
3085 if (ctx && ctx->nr_events) {
3086 if (ctx->nr_events != ctx->nr_active)
3093 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3094 perf_pmu_disable(cpuctx->ctx.pmu);
3096 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3098 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3100 rotate_ctx(&cpuctx->ctx);
3104 perf_event_sched_in(cpuctx, ctx, current);
3106 perf_pmu_enable(cpuctx->ctx.pmu);
3107 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3113 #ifdef CONFIG_NO_HZ_FULL
3114 bool perf_event_can_stop_tick(void)
3116 if (atomic_read(&nr_freq_events) ||
3117 __this_cpu_read(perf_throttled_count))
3124 void perf_event_task_tick(void)
3126 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3127 struct perf_event_context *ctx, *tmp;
3130 WARN_ON(!irqs_disabled());
3132 __this_cpu_inc(perf_throttled_seq);
3133 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3135 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3136 perf_adjust_freq_unthr_context(ctx, throttled);
3139 static int event_enable_on_exec(struct perf_event *event,
3140 struct perf_event_context *ctx)
3142 if (!event->attr.enable_on_exec)
3145 event->attr.enable_on_exec = 0;
3146 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3149 __perf_event_mark_enabled(event);
3155 * Enable all of a task's events that have been marked enable-on-exec.
3156 * This expects task == current.
3158 static void perf_event_enable_on_exec(int ctxn)
3160 struct perf_event_context *ctx, *clone_ctx = NULL;
3161 struct perf_event *event;
3162 unsigned long flags;
3166 local_irq_save(flags);
3167 ctx = current->perf_event_ctxp[ctxn];
3168 if (!ctx || !ctx->nr_events)
3172 * We must ctxsw out cgroup events to avoid conflict
3173 * when invoking perf_task_event_sched_in() later on
3174 * in this function. Otherwise we end up trying to
3175 * ctxswin cgroup events which are already scheduled
3178 perf_cgroup_sched_out(current, NULL);
3180 raw_spin_lock(&ctx->lock);
3181 task_ctx_sched_out(ctx);
3183 list_for_each_entry(event, &ctx->event_list, event_entry) {
3184 ret = event_enable_on_exec(event, ctx);
3190 * Unclone this context if we enabled any event.
3193 clone_ctx = unclone_ctx(ctx);
3195 raw_spin_unlock(&ctx->lock);
3198 * Also calls ctxswin for cgroup events, if any:
3200 perf_event_context_sched_in(ctx, ctx->task);
3202 local_irq_restore(flags);
3208 void perf_event_exec(void)
3213 for_each_task_context_nr(ctxn)
3214 perf_event_enable_on_exec(ctxn);
3218 struct perf_read_data {
3219 struct perf_event *event;
3225 * Cross CPU call to read the hardware event
3227 static void __perf_event_read(void *info)
3229 struct perf_read_data *data = info;
3230 struct perf_event *sub, *event = data->event;
3231 struct perf_event_context *ctx = event->ctx;
3232 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3233 struct pmu *pmu = event->pmu;
3236 * If this is a task context, we need to check whether it is
3237 * the current task context of this cpu. If not it has been
3238 * scheduled out before the smp call arrived. In that case
3239 * event->count would have been updated to a recent sample
3240 * when the event was scheduled out.
3242 if (ctx->task && cpuctx->task_ctx != ctx)
3245 raw_spin_lock(&ctx->lock);
3246 if (ctx->is_active) {
3247 update_context_time(ctx);
3248 update_cgrp_time_from_event(event);
3251 update_event_times(event);
3252 if (event->state != PERF_EVENT_STATE_ACTIVE)
3261 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3265 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3266 update_event_times(sub);
3267 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3269 * Use sibling's PMU rather than @event's since
3270 * sibling could be on different (eg: software) PMU.
3272 sub->pmu->read(sub);
3276 data->ret = pmu->commit_txn(pmu);
3279 raw_spin_unlock(&ctx->lock);
3282 static inline u64 perf_event_count(struct perf_event *event)
3284 if (event->pmu->count)
3285 return event->pmu->count(event);
3287 return __perf_event_count(event);
3291 * NMI-safe method to read a local event, that is an event that
3293 * - either for the current task, or for this CPU
3294 * - does not have inherit set, for inherited task events
3295 * will not be local and we cannot read them atomically
3296 * - must not have a pmu::count method
3298 u64 perf_event_read_local(struct perf_event *event)
3300 unsigned long flags;
3304 * Disabling interrupts avoids all counter scheduling (context
3305 * switches, timer based rotation and IPIs).
3307 local_irq_save(flags);
3309 /* If this is a per-task event, it must be for current */
3310 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3311 event->hw.target != current);
3313 /* If this is a per-CPU event, it must be for this CPU */
3314 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3315 event->cpu != smp_processor_id());
3318 * It must not be an event with inherit set, we cannot read
3319 * all child counters from atomic context.
3321 WARN_ON_ONCE(event->attr.inherit);
3324 * It must not have a pmu::count method, those are not
3327 WARN_ON_ONCE(event->pmu->count);
3330 * If the event is currently on this CPU, its either a per-task event,
3331 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3334 if (event->oncpu == smp_processor_id())
3335 event->pmu->read(event);
3337 val = local64_read(&event->count);
3338 local_irq_restore(flags);
3343 static int perf_event_read(struct perf_event *event, bool group)
3348 * If event is enabled and currently active on a CPU, update the
3349 * value in the event structure:
3351 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3352 struct perf_read_data data = {
3357 smp_call_function_single(event->oncpu,
3358 __perf_event_read, &data, 1);
3360 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3361 struct perf_event_context *ctx = event->ctx;
3362 unsigned long flags;
3364 raw_spin_lock_irqsave(&ctx->lock, flags);
3366 * may read while context is not active
3367 * (e.g., thread is blocked), in that case
3368 * we cannot update context time
3370 if (ctx->is_active) {
3371 update_context_time(ctx);
3372 update_cgrp_time_from_event(event);
3375 update_group_times(event);
3377 update_event_times(event);
3378 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3385 * Initialize the perf_event context in a task_struct:
3387 static void __perf_event_init_context(struct perf_event_context *ctx)
3389 raw_spin_lock_init(&ctx->lock);
3390 mutex_init(&ctx->mutex);
3391 INIT_LIST_HEAD(&ctx->active_ctx_list);
3392 INIT_LIST_HEAD(&ctx->pinned_groups);
3393 INIT_LIST_HEAD(&ctx->flexible_groups);
3394 INIT_LIST_HEAD(&ctx->event_list);
3395 atomic_set(&ctx->refcount, 1);
3396 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3399 static struct perf_event_context *
3400 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3402 struct perf_event_context *ctx;
3404 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3408 __perf_event_init_context(ctx);
3411 get_task_struct(task);
3418 static struct task_struct *
3419 find_lively_task_by_vpid(pid_t vpid)
3421 struct task_struct *task;
3427 task = find_task_by_vpid(vpid);
3429 get_task_struct(task);
3433 return ERR_PTR(-ESRCH);
3439 * Returns a matching context with refcount and pincount.
3441 static struct perf_event_context *
3442 find_get_context(struct pmu *pmu, struct task_struct *task,
3443 struct perf_event *event)
3445 struct perf_event_context *ctx, *clone_ctx = NULL;
3446 struct perf_cpu_context *cpuctx;
3447 void *task_ctx_data = NULL;
3448 unsigned long flags;
3450 int cpu = event->cpu;
3453 /* Must be root to operate on a CPU event: */
3454 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3455 return ERR_PTR(-EACCES);
3458 * We could be clever and allow to attach a event to an
3459 * offline CPU and activate it when the CPU comes up, but
3462 if (!cpu_online(cpu))
3463 return ERR_PTR(-ENODEV);
3465 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3474 ctxn = pmu->task_ctx_nr;
3478 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3479 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3480 if (!task_ctx_data) {
3487 ctx = perf_lock_task_context(task, ctxn, &flags);
3489 clone_ctx = unclone_ctx(ctx);
3492 if (task_ctx_data && !ctx->task_ctx_data) {
3493 ctx->task_ctx_data = task_ctx_data;
3494 task_ctx_data = NULL;
3496 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3501 ctx = alloc_perf_context(pmu, task);
3506 if (task_ctx_data) {
3507 ctx->task_ctx_data = task_ctx_data;
3508 task_ctx_data = NULL;
3512 mutex_lock(&task->perf_event_mutex);
3514 * If it has already passed perf_event_exit_task().
3515 * we must see PF_EXITING, it takes this mutex too.
3517 if (task->flags & PF_EXITING)
3519 else if (task->perf_event_ctxp[ctxn])
3524 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3526 mutex_unlock(&task->perf_event_mutex);
3528 if (unlikely(err)) {
3537 kfree(task_ctx_data);
3541 kfree(task_ctx_data);
3542 return ERR_PTR(err);
3545 static void perf_event_free_filter(struct perf_event *event);
3546 static void perf_event_free_bpf_prog(struct perf_event *event);
3548 static void free_event_rcu(struct rcu_head *head)
3550 struct perf_event *event;
3552 event = container_of(head, struct perf_event, rcu_head);
3554 put_pid_ns(event->ns);
3555 perf_event_free_filter(event);
3559 static void ring_buffer_attach(struct perf_event *event,
3560 struct ring_buffer *rb);
3562 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3567 if (is_cgroup_event(event))
3568 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3571 static void unaccount_event(struct perf_event *event)
3576 if (event->attach_state & PERF_ATTACH_TASK)
3577 static_key_slow_dec_deferred(&perf_sched_events);
3578 if (event->attr.mmap || event->attr.mmap_data)
3579 atomic_dec(&nr_mmap_events);
3580 if (event->attr.comm)
3581 atomic_dec(&nr_comm_events);
3582 if (event->attr.task)
3583 atomic_dec(&nr_task_events);
3584 if (event->attr.freq)
3585 atomic_dec(&nr_freq_events);
3586 if (event->attr.context_switch) {
3587 static_key_slow_dec_deferred(&perf_sched_events);
3588 atomic_dec(&nr_switch_events);
3590 if (is_cgroup_event(event))
3591 static_key_slow_dec_deferred(&perf_sched_events);
3592 if (has_branch_stack(event))
3593 static_key_slow_dec_deferred(&perf_sched_events);
3595 unaccount_event_cpu(event, event->cpu);
3599 * The following implement mutual exclusion of events on "exclusive" pmus
3600 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3601 * at a time, so we disallow creating events that might conflict, namely:
3603 * 1) cpu-wide events in the presence of per-task events,
3604 * 2) per-task events in the presence of cpu-wide events,
3605 * 3) two matching events on the same context.
3607 * The former two cases are handled in the allocation path (perf_event_alloc(),
3608 * __free_event()), the latter -- before the first perf_install_in_context().
3610 static int exclusive_event_init(struct perf_event *event)
3612 struct pmu *pmu = event->pmu;
3614 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3618 * Prevent co-existence of per-task and cpu-wide events on the
3619 * same exclusive pmu.
3621 * Negative pmu::exclusive_cnt means there are cpu-wide
3622 * events on this "exclusive" pmu, positive means there are
3625 * Since this is called in perf_event_alloc() path, event::ctx
3626 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3627 * to mean "per-task event", because unlike other attach states it
3628 * never gets cleared.
3630 if (event->attach_state & PERF_ATTACH_TASK) {
3631 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3634 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3641 static void exclusive_event_destroy(struct perf_event *event)
3643 struct pmu *pmu = event->pmu;
3645 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3648 /* see comment in exclusive_event_init() */
3649 if (event->attach_state & PERF_ATTACH_TASK)
3650 atomic_dec(&pmu->exclusive_cnt);
3652 atomic_inc(&pmu->exclusive_cnt);
3655 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3657 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3658 (e1->cpu == e2->cpu ||
3665 /* Called under the same ctx::mutex as perf_install_in_context() */
3666 static bool exclusive_event_installable(struct perf_event *event,
3667 struct perf_event_context *ctx)
3669 struct perf_event *iter_event;
3670 struct pmu *pmu = event->pmu;
3672 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3675 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3676 if (exclusive_event_match(iter_event, event))
3683 static void __free_event(struct perf_event *event)
3685 if (!event->parent) {
3686 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3687 put_callchain_buffers();
3690 perf_event_free_bpf_prog(event);
3693 event->destroy(event);
3696 put_ctx(event->ctx);
3699 exclusive_event_destroy(event);
3700 module_put(event->pmu->module);
3703 call_rcu(&event->rcu_head, free_event_rcu);
3706 static void _free_event(struct perf_event *event)
3708 irq_work_sync(&event->pending);
3710 unaccount_event(event);
3714 * Can happen when we close an event with re-directed output.
3716 * Since we have a 0 refcount, perf_mmap_close() will skip
3717 * over us; possibly making our ring_buffer_put() the last.
3719 mutex_lock(&event->mmap_mutex);
3720 ring_buffer_attach(event, NULL);
3721 mutex_unlock(&event->mmap_mutex);
3724 if (is_cgroup_event(event))
3725 perf_detach_cgroup(event);
3727 __free_event(event);
3731 * Used to free events which have a known refcount of 1, such as in error paths
3732 * where the event isn't exposed yet and inherited events.
3734 static void free_event(struct perf_event *event)
3736 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3737 "unexpected event refcount: %ld; ptr=%p\n",
3738 atomic_long_read(&event->refcount), event)) {
3739 /* leak to avoid use-after-free */
3747 * Remove user event from the owner task.
3749 static void perf_remove_from_owner(struct perf_event *event)
3751 struct task_struct *owner;
3754 owner = ACCESS_ONCE(event->owner);
3756 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3757 * !owner it means the list deletion is complete and we can indeed
3758 * free this event, otherwise we need to serialize on
3759 * owner->perf_event_mutex.
3761 smp_read_barrier_depends();
3764 * Since delayed_put_task_struct() also drops the last
3765 * task reference we can safely take a new reference
3766 * while holding the rcu_read_lock().
3768 get_task_struct(owner);
3774 * If we're here through perf_event_exit_task() we're already
3775 * holding ctx->mutex which would be an inversion wrt. the
3776 * normal lock order.
3778 * However we can safely take this lock because its the child
3781 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3784 * We have to re-check the event->owner field, if it is cleared
3785 * we raced with perf_event_exit_task(), acquiring the mutex
3786 * ensured they're done, and we can proceed with freeing the
3790 list_del_init(&event->owner_entry);
3791 mutex_unlock(&owner->perf_event_mutex);
3792 put_task_struct(owner);
3796 static void put_event(struct perf_event *event)
3798 struct perf_event_context *ctx;
3800 if (!atomic_long_dec_and_test(&event->refcount))
3803 if (!is_kernel_event(event))
3804 perf_remove_from_owner(event);
3807 * There are two ways this annotation is useful:
3809 * 1) there is a lock recursion from perf_event_exit_task
3810 * see the comment there.
3812 * 2) there is a lock-inversion with mmap_sem through
3813 * perf_read_group(), which takes faults while
3814 * holding ctx->mutex, however this is called after
3815 * the last filedesc died, so there is no possibility
3816 * to trigger the AB-BA case.
3818 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3819 WARN_ON_ONCE(ctx->parent_ctx);
3820 perf_remove_from_context(event, true);
3821 perf_event_ctx_unlock(event, ctx);
3826 int perf_event_release_kernel(struct perf_event *event)
3831 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3834 * Called when the last reference to the file is gone.
3836 static int perf_release(struct inode *inode, struct file *file)
3838 put_event(file->private_data);
3843 * Remove all orphanes events from the context.
3845 static void orphans_remove_work(struct work_struct *work)
3847 struct perf_event_context *ctx;
3848 struct perf_event *event, *tmp;
3850 ctx = container_of(work, struct perf_event_context,
3851 orphans_remove.work);
3853 mutex_lock(&ctx->mutex);
3854 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3855 struct perf_event *parent_event = event->parent;
3857 if (!is_orphaned_child(event))
3860 perf_remove_from_context(event, true);
3862 mutex_lock(&parent_event->child_mutex);
3863 list_del_init(&event->child_list);
3864 mutex_unlock(&parent_event->child_mutex);
3867 put_event(parent_event);
3870 raw_spin_lock_irq(&ctx->lock);
3871 ctx->orphans_remove_sched = false;
3872 raw_spin_unlock_irq(&ctx->lock);
3873 mutex_unlock(&ctx->mutex);
3878 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3880 struct perf_event *child;
3886 mutex_lock(&event->child_mutex);
3888 (void)perf_event_read(event, false);
3889 total += perf_event_count(event);
3891 *enabled += event->total_time_enabled +
3892 atomic64_read(&event->child_total_time_enabled);
3893 *running += event->total_time_running +
3894 atomic64_read(&event->child_total_time_running);
3896 list_for_each_entry(child, &event->child_list, child_list) {
3897 (void)perf_event_read(child, false);
3898 total += perf_event_count(child);
3899 *enabled += child->total_time_enabled;
3900 *running += child->total_time_running;
3902 mutex_unlock(&event->child_mutex);
3906 EXPORT_SYMBOL_GPL(perf_event_read_value);
3908 static int __perf_read_group_add(struct perf_event *leader,
3909 u64 read_format, u64 *values)
3911 struct perf_event *sub;
3912 int n = 1; /* skip @nr */
3915 ret = perf_event_read(leader, true);
3920 * Since we co-schedule groups, {enabled,running} times of siblings
3921 * will be identical to those of the leader, so we only publish one
3924 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3925 values[n++] += leader->total_time_enabled +
3926 atomic64_read(&leader->child_total_time_enabled);
3929 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3930 values[n++] += leader->total_time_running +
3931 atomic64_read(&leader->child_total_time_running);
3935 * Write {count,id} tuples for every sibling.
3937 values[n++] += perf_event_count(leader);
3938 if (read_format & PERF_FORMAT_ID)
3939 values[n++] = primary_event_id(leader);
3941 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3942 values[n++] += perf_event_count(sub);
3943 if (read_format & PERF_FORMAT_ID)
3944 values[n++] = primary_event_id(sub);
3950 static int perf_read_group(struct perf_event *event,
3951 u64 read_format, char __user *buf)
3953 struct perf_event *leader = event->group_leader, *child;
3954 struct perf_event_context *ctx = leader->ctx;
3958 lockdep_assert_held(&ctx->mutex);
3960 values = kzalloc(event->read_size, GFP_KERNEL);
3964 values[0] = 1 + leader->nr_siblings;
3967 * By locking the child_mutex of the leader we effectively
3968 * lock the child list of all siblings.. XXX explain how.
3970 mutex_lock(&leader->child_mutex);
3972 ret = __perf_read_group_add(leader, read_format, values);
3976 list_for_each_entry(child, &leader->child_list, child_list) {
3977 ret = __perf_read_group_add(child, read_format, values);
3982 mutex_unlock(&leader->child_mutex);
3984 ret = event->read_size;
3985 if (copy_to_user(buf, values, event->read_size))
3990 mutex_unlock(&leader->child_mutex);
3996 static int perf_read_one(struct perf_event *event,
3997 u64 read_format, char __user *buf)
3999 u64 enabled, running;
4003 values[n++] = perf_event_read_value(event, &enabled, &running);
4004 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4005 values[n++] = enabled;
4006 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4007 values[n++] = running;
4008 if (read_format & PERF_FORMAT_ID)
4009 values[n++] = primary_event_id(event);
4011 if (copy_to_user(buf, values, n * sizeof(u64)))
4014 return n * sizeof(u64);
4017 static bool is_event_hup(struct perf_event *event)
4021 if (event->state != PERF_EVENT_STATE_EXIT)
4024 mutex_lock(&event->child_mutex);
4025 no_children = list_empty(&event->child_list);
4026 mutex_unlock(&event->child_mutex);
4031 * Read the performance event - simple non blocking version for now
4034 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4036 u64 read_format = event->attr.read_format;
4040 * Return end-of-file for a read on a event that is in
4041 * error state (i.e. because it was pinned but it couldn't be
4042 * scheduled on to the CPU at some point).
4044 if (event->state == PERF_EVENT_STATE_ERROR)
4047 if (count < event->read_size)
4050 WARN_ON_ONCE(event->ctx->parent_ctx);
4051 if (read_format & PERF_FORMAT_GROUP)
4052 ret = perf_read_group(event, read_format, buf);
4054 ret = perf_read_one(event, read_format, buf);
4060 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4062 struct perf_event *event = file->private_data;
4063 struct perf_event_context *ctx;
4066 ctx = perf_event_ctx_lock(event);
4067 ret = __perf_read(event, buf, count);
4068 perf_event_ctx_unlock(event, ctx);
4073 static unsigned int perf_poll(struct file *file, poll_table *wait)
4075 struct perf_event *event = file->private_data;
4076 struct ring_buffer *rb;
4077 unsigned int events = POLLHUP;
4079 poll_wait(file, &event->waitq, wait);
4081 if (is_event_hup(event))
4085 * Pin the event->rb by taking event->mmap_mutex; otherwise
4086 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4088 mutex_lock(&event->mmap_mutex);
4091 events = atomic_xchg(&rb->poll, 0);
4092 mutex_unlock(&event->mmap_mutex);
4096 static void _perf_event_reset(struct perf_event *event)
4098 (void)perf_event_read(event, false);
4099 local64_set(&event->count, 0);
4100 perf_event_update_userpage(event);
4104 * Holding the top-level event's child_mutex means that any
4105 * descendant process that has inherited this event will block
4106 * in sync_child_event if it goes to exit, thus satisfying the
4107 * task existence requirements of perf_event_enable/disable.
4109 static void perf_event_for_each_child(struct perf_event *event,
4110 void (*func)(struct perf_event *))
4112 struct perf_event *child;
4114 WARN_ON_ONCE(event->ctx->parent_ctx);
4116 mutex_lock(&event->child_mutex);
4118 list_for_each_entry(child, &event->child_list, child_list)
4120 mutex_unlock(&event->child_mutex);
4123 static void perf_event_for_each(struct perf_event *event,
4124 void (*func)(struct perf_event *))
4126 struct perf_event_context *ctx = event->ctx;
4127 struct perf_event *sibling;
4129 lockdep_assert_held(&ctx->mutex);
4131 event = event->group_leader;
4133 perf_event_for_each_child(event, func);
4134 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4135 perf_event_for_each_child(sibling, func);
4138 struct period_event {
4139 struct perf_event *event;
4143 static int __perf_event_period(void *info)
4145 struct period_event *pe = info;
4146 struct perf_event *event = pe->event;
4147 struct perf_event_context *ctx = event->ctx;
4148 u64 value = pe->value;
4151 raw_spin_lock(&ctx->lock);
4152 if (event->attr.freq) {
4153 event->attr.sample_freq = value;
4155 event->attr.sample_period = value;
4156 event->hw.sample_period = value;
4159 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4161 perf_pmu_disable(ctx->pmu);
4162 event->pmu->stop(event, PERF_EF_UPDATE);
4165 local64_set(&event->hw.period_left, 0);
4168 event->pmu->start(event, PERF_EF_RELOAD);
4169 perf_pmu_enable(ctx->pmu);
4171 raw_spin_unlock(&ctx->lock);
4176 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4178 struct period_event pe = { .event = event, };
4179 struct perf_event_context *ctx = event->ctx;
4180 struct task_struct *task;
4183 if (!is_sampling_event(event))
4186 if (copy_from_user(&value, arg, sizeof(value)))
4192 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4199 cpu_function_call(event->cpu, __perf_event_period, &pe);
4204 if (!task_function_call(task, __perf_event_period, &pe))
4207 raw_spin_lock_irq(&ctx->lock);
4208 if (ctx->is_active) {
4209 raw_spin_unlock_irq(&ctx->lock);
4214 if (event->attr.freq) {
4215 event->attr.sample_freq = value;
4217 event->attr.sample_period = value;
4218 event->hw.sample_period = value;
4221 local64_set(&event->hw.period_left, 0);
4222 raw_spin_unlock_irq(&ctx->lock);
4227 static const struct file_operations perf_fops;
4229 static inline int perf_fget_light(int fd, struct fd *p)
4231 struct fd f = fdget(fd);
4235 if (f.file->f_op != &perf_fops) {
4243 static int perf_event_set_output(struct perf_event *event,
4244 struct perf_event *output_event);
4245 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4246 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4248 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4250 void (*func)(struct perf_event *);
4254 case PERF_EVENT_IOC_ENABLE:
4255 func = _perf_event_enable;
4257 case PERF_EVENT_IOC_DISABLE:
4258 func = _perf_event_disable;
4260 case PERF_EVENT_IOC_RESET:
4261 func = _perf_event_reset;
4264 case PERF_EVENT_IOC_REFRESH:
4265 return _perf_event_refresh(event, arg);
4267 case PERF_EVENT_IOC_PERIOD:
4268 return perf_event_period(event, (u64 __user *)arg);
4270 case PERF_EVENT_IOC_ID:
4272 u64 id = primary_event_id(event);
4274 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4279 case PERF_EVENT_IOC_SET_OUTPUT:
4283 struct perf_event *output_event;
4285 ret = perf_fget_light(arg, &output);
4288 output_event = output.file->private_data;
4289 ret = perf_event_set_output(event, output_event);
4292 ret = perf_event_set_output(event, NULL);
4297 case PERF_EVENT_IOC_SET_FILTER:
4298 return perf_event_set_filter(event, (void __user *)arg);
4300 case PERF_EVENT_IOC_SET_BPF:
4301 return perf_event_set_bpf_prog(event, arg);
4307 if (flags & PERF_IOC_FLAG_GROUP)
4308 perf_event_for_each(event, func);
4310 perf_event_for_each_child(event, func);
4315 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4317 struct perf_event *event = file->private_data;
4318 struct perf_event_context *ctx;
4321 ctx = perf_event_ctx_lock(event);
4322 ret = _perf_ioctl(event, cmd, arg);
4323 perf_event_ctx_unlock(event, ctx);
4328 #ifdef CONFIG_COMPAT
4329 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4332 switch (_IOC_NR(cmd)) {
4333 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4334 case _IOC_NR(PERF_EVENT_IOC_ID):
4335 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4336 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4337 cmd &= ~IOCSIZE_MASK;
4338 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4342 return perf_ioctl(file, cmd, arg);
4345 # define perf_compat_ioctl NULL
4348 int perf_event_task_enable(void)
4350 struct perf_event_context *ctx;
4351 struct perf_event *event;
4353 mutex_lock(¤t->perf_event_mutex);
4354 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4355 ctx = perf_event_ctx_lock(event);
4356 perf_event_for_each_child(event, _perf_event_enable);
4357 perf_event_ctx_unlock(event, ctx);
4359 mutex_unlock(¤t->perf_event_mutex);
4364 int perf_event_task_disable(void)
4366 struct perf_event_context *ctx;
4367 struct perf_event *event;
4369 mutex_lock(¤t->perf_event_mutex);
4370 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4371 ctx = perf_event_ctx_lock(event);
4372 perf_event_for_each_child(event, _perf_event_disable);
4373 perf_event_ctx_unlock(event, ctx);
4375 mutex_unlock(¤t->perf_event_mutex);
4380 static int perf_event_index(struct perf_event *event)
4382 if (event->hw.state & PERF_HES_STOPPED)
4385 if (event->state != PERF_EVENT_STATE_ACTIVE)
4388 return event->pmu->event_idx(event);
4391 static void calc_timer_values(struct perf_event *event,
4398 *now = perf_clock();
4399 ctx_time = event->shadow_ctx_time + *now;
4400 *enabled = ctx_time - event->tstamp_enabled;
4401 *running = ctx_time - event->tstamp_running;
4404 static void perf_event_init_userpage(struct perf_event *event)
4406 struct perf_event_mmap_page *userpg;
4407 struct ring_buffer *rb;
4410 rb = rcu_dereference(event->rb);
4414 userpg = rb->user_page;
4416 /* Allow new userspace to detect that bit 0 is deprecated */
4417 userpg->cap_bit0_is_deprecated = 1;
4418 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4419 userpg->data_offset = PAGE_SIZE;
4420 userpg->data_size = perf_data_size(rb);
4426 void __weak arch_perf_update_userpage(
4427 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4432 * Callers need to ensure there can be no nesting of this function, otherwise
4433 * the seqlock logic goes bad. We can not serialize this because the arch
4434 * code calls this from NMI context.
4436 void perf_event_update_userpage(struct perf_event *event)
4438 struct perf_event_mmap_page *userpg;
4439 struct ring_buffer *rb;
4440 u64 enabled, running, now;
4443 rb = rcu_dereference(event->rb);
4448 * compute total_time_enabled, total_time_running
4449 * based on snapshot values taken when the event
4450 * was last scheduled in.
4452 * we cannot simply called update_context_time()
4453 * because of locking issue as we can be called in
4456 calc_timer_values(event, &now, &enabled, &running);
4458 userpg = rb->user_page;
4460 * Disable preemption so as to not let the corresponding user-space
4461 * spin too long if we get preempted.
4466 userpg->index = perf_event_index(event);
4467 userpg->offset = perf_event_count(event);
4469 userpg->offset -= local64_read(&event->hw.prev_count);
4471 userpg->time_enabled = enabled +
4472 atomic64_read(&event->child_total_time_enabled);
4474 userpg->time_running = running +
4475 atomic64_read(&event->child_total_time_running);
4477 arch_perf_update_userpage(event, userpg, now);
4486 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4488 struct perf_event *event = vma->vm_file->private_data;
4489 struct ring_buffer *rb;
4490 int ret = VM_FAULT_SIGBUS;
4492 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4493 if (vmf->pgoff == 0)
4499 rb = rcu_dereference(event->rb);
4503 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4506 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4510 get_page(vmf->page);
4511 vmf->page->mapping = vma->vm_file->f_mapping;
4512 vmf->page->index = vmf->pgoff;
4521 static void ring_buffer_attach(struct perf_event *event,
4522 struct ring_buffer *rb)
4524 struct ring_buffer *old_rb = NULL;
4525 unsigned long flags;
4529 * Should be impossible, we set this when removing
4530 * event->rb_entry and wait/clear when adding event->rb_entry.
4532 WARN_ON_ONCE(event->rcu_pending);
4535 spin_lock_irqsave(&old_rb->event_lock, flags);
4536 list_del_rcu(&event->rb_entry);
4537 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4539 event->rcu_batches = get_state_synchronize_rcu();
4540 event->rcu_pending = 1;
4544 if (event->rcu_pending) {
4545 cond_synchronize_rcu(event->rcu_batches);
4546 event->rcu_pending = 0;
4549 spin_lock_irqsave(&rb->event_lock, flags);
4550 list_add_rcu(&event->rb_entry, &rb->event_list);
4551 spin_unlock_irqrestore(&rb->event_lock, flags);
4554 rcu_assign_pointer(event->rb, rb);
4557 ring_buffer_put(old_rb);
4559 * Since we detached before setting the new rb, so that we
4560 * could attach the new rb, we could have missed a wakeup.
4563 wake_up_all(&event->waitq);
4567 static void ring_buffer_wakeup(struct perf_event *event)
4569 struct ring_buffer *rb;
4572 rb = rcu_dereference(event->rb);
4574 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4575 wake_up_all(&event->waitq);
4580 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4582 struct ring_buffer *rb;
4585 rb = rcu_dereference(event->rb);
4587 if (!atomic_inc_not_zero(&rb->refcount))
4595 void ring_buffer_put(struct ring_buffer *rb)
4597 if (!atomic_dec_and_test(&rb->refcount))
4600 WARN_ON_ONCE(!list_empty(&rb->event_list));
4602 call_rcu(&rb->rcu_head, rb_free_rcu);
4605 static void perf_mmap_open(struct vm_area_struct *vma)
4607 struct perf_event *event = vma->vm_file->private_data;
4609 atomic_inc(&event->mmap_count);
4610 atomic_inc(&event->rb->mmap_count);
4613 atomic_inc(&event->rb->aux_mmap_count);
4615 if (event->pmu->event_mapped)
4616 event->pmu->event_mapped(event);
4620 * A buffer can be mmap()ed multiple times; either directly through the same
4621 * event, or through other events by use of perf_event_set_output().
4623 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4624 * the buffer here, where we still have a VM context. This means we need
4625 * to detach all events redirecting to us.
4627 static void perf_mmap_close(struct vm_area_struct *vma)
4629 struct perf_event *event = vma->vm_file->private_data;
4631 struct ring_buffer *rb = ring_buffer_get(event);
4632 struct user_struct *mmap_user = rb->mmap_user;
4633 int mmap_locked = rb->mmap_locked;
4634 unsigned long size = perf_data_size(rb);
4636 if (event->pmu->event_unmapped)
4637 event->pmu->event_unmapped(event);
4640 * rb->aux_mmap_count will always drop before rb->mmap_count and
4641 * event->mmap_count, so it is ok to use event->mmap_mutex to
4642 * serialize with perf_mmap here.
4644 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4645 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4646 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4647 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4650 mutex_unlock(&event->mmap_mutex);
4653 atomic_dec(&rb->mmap_count);
4655 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4658 ring_buffer_attach(event, NULL);
4659 mutex_unlock(&event->mmap_mutex);
4661 /* If there's still other mmap()s of this buffer, we're done. */
4662 if (atomic_read(&rb->mmap_count))
4666 * No other mmap()s, detach from all other events that might redirect
4667 * into the now unreachable buffer. Somewhat complicated by the
4668 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4672 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4673 if (!atomic_long_inc_not_zero(&event->refcount)) {
4675 * This event is en-route to free_event() which will
4676 * detach it and remove it from the list.
4682 mutex_lock(&event->mmap_mutex);
4684 * Check we didn't race with perf_event_set_output() which can
4685 * swizzle the rb from under us while we were waiting to
4686 * acquire mmap_mutex.
4688 * If we find a different rb; ignore this event, a next
4689 * iteration will no longer find it on the list. We have to
4690 * still restart the iteration to make sure we're not now
4691 * iterating the wrong list.
4693 if (event->rb == rb)
4694 ring_buffer_attach(event, NULL);
4696 mutex_unlock(&event->mmap_mutex);
4700 * Restart the iteration; either we're on the wrong list or
4701 * destroyed its integrity by doing a deletion.
4708 * It could be there's still a few 0-ref events on the list; they'll
4709 * get cleaned up by free_event() -- they'll also still have their
4710 * ref on the rb and will free it whenever they are done with it.
4712 * Aside from that, this buffer is 'fully' detached and unmapped,
4713 * undo the VM accounting.
4716 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4717 vma->vm_mm->pinned_vm -= mmap_locked;
4718 free_uid(mmap_user);
4721 ring_buffer_put(rb); /* could be last */
4724 static const struct vm_operations_struct perf_mmap_vmops = {
4725 .open = perf_mmap_open,
4726 .close = perf_mmap_close, /* non mergable */
4727 .fault = perf_mmap_fault,
4728 .page_mkwrite = perf_mmap_fault,
4731 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4733 struct perf_event *event = file->private_data;
4734 unsigned long user_locked, user_lock_limit;
4735 struct user_struct *user = current_user();
4736 unsigned long locked, lock_limit;
4737 struct ring_buffer *rb = NULL;
4738 unsigned long vma_size;
4739 unsigned long nr_pages;
4740 long user_extra = 0, extra = 0;
4741 int ret = 0, flags = 0;
4744 * Don't allow mmap() of inherited per-task counters. This would
4745 * create a performance issue due to all children writing to the
4748 if (event->cpu == -1 && event->attr.inherit)
4751 if (!(vma->vm_flags & VM_SHARED))
4754 vma_size = vma->vm_end - vma->vm_start;
4756 if (vma->vm_pgoff == 0) {
4757 nr_pages = (vma_size / PAGE_SIZE) - 1;
4760 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4761 * mapped, all subsequent mappings should have the same size
4762 * and offset. Must be above the normal perf buffer.
4764 u64 aux_offset, aux_size;
4769 nr_pages = vma_size / PAGE_SIZE;
4771 mutex_lock(&event->mmap_mutex);
4778 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4779 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4781 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4784 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4787 /* already mapped with a different offset */
4788 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4791 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4794 /* already mapped with a different size */
4795 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4798 if (!is_power_of_2(nr_pages))
4801 if (!atomic_inc_not_zero(&rb->mmap_count))
4804 if (rb_has_aux(rb)) {
4805 atomic_inc(&rb->aux_mmap_count);
4810 atomic_set(&rb->aux_mmap_count, 1);
4811 user_extra = nr_pages;
4817 * If we have rb pages ensure they're a power-of-two number, so we
4818 * can do bitmasks instead of modulo.
4820 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4823 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4826 WARN_ON_ONCE(event->ctx->parent_ctx);
4828 mutex_lock(&event->mmap_mutex);
4830 if (event->rb->nr_pages != nr_pages) {
4835 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4837 * Raced against perf_mmap_close() through
4838 * perf_event_set_output(). Try again, hope for better
4841 mutex_unlock(&event->mmap_mutex);
4848 user_extra = nr_pages + 1;
4851 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4854 * Increase the limit linearly with more CPUs:
4856 user_lock_limit *= num_online_cpus();
4858 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4860 if (user_locked > user_lock_limit)
4861 extra = user_locked - user_lock_limit;
4863 lock_limit = rlimit(RLIMIT_MEMLOCK);
4864 lock_limit >>= PAGE_SHIFT;
4865 locked = vma->vm_mm->pinned_vm + extra;
4867 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4868 !capable(CAP_IPC_LOCK)) {
4873 WARN_ON(!rb && event->rb);
4875 if (vma->vm_flags & VM_WRITE)
4876 flags |= RING_BUFFER_WRITABLE;
4879 rb = rb_alloc(nr_pages,
4880 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4888 atomic_set(&rb->mmap_count, 1);
4889 rb->mmap_user = get_current_user();
4890 rb->mmap_locked = extra;
4892 ring_buffer_attach(event, rb);
4894 perf_event_init_userpage(event);
4895 perf_event_update_userpage(event);
4897 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4898 event->attr.aux_watermark, flags);
4900 rb->aux_mmap_locked = extra;
4905 atomic_long_add(user_extra, &user->locked_vm);
4906 vma->vm_mm->pinned_vm += extra;
4908 atomic_inc(&event->mmap_count);
4910 atomic_dec(&rb->mmap_count);
4913 mutex_unlock(&event->mmap_mutex);
4916 * Since pinned accounting is per vm we cannot allow fork() to copy our
4919 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4920 vma->vm_ops = &perf_mmap_vmops;
4922 if (event->pmu->event_mapped)
4923 event->pmu->event_mapped(event);
4928 static int perf_fasync(int fd, struct file *filp, int on)
4930 struct inode *inode = file_inode(filp);
4931 struct perf_event *event = filp->private_data;
4934 mutex_lock(&inode->i_mutex);
4935 retval = fasync_helper(fd, filp, on, &event->fasync);
4936 mutex_unlock(&inode->i_mutex);
4944 static const struct file_operations perf_fops = {
4945 .llseek = no_llseek,
4946 .release = perf_release,
4949 .unlocked_ioctl = perf_ioctl,
4950 .compat_ioctl = perf_compat_ioctl,
4952 .fasync = perf_fasync,
4958 * If there's data, ensure we set the poll() state and publish everything
4959 * to user-space before waking everybody up.
4962 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
4964 /* only the parent has fasync state */
4966 event = event->parent;
4967 return &event->fasync;
4970 void perf_event_wakeup(struct perf_event *event)
4972 ring_buffer_wakeup(event);
4974 if (event->pending_kill) {
4975 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
4976 event->pending_kill = 0;
4980 static void perf_pending_event(struct irq_work *entry)
4982 struct perf_event *event = container_of(entry,
4983 struct perf_event, pending);
4986 rctx = perf_swevent_get_recursion_context();
4988 * If we 'fail' here, that's OK, it means recursion is already disabled
4989 * and we won't recurse 'further'.
4992 if (event->pending_disable) {
4993 event->pending_disable = 0;
4994 __perf_event_disable(event);
4997 if (event->pending_wakeup) {
4998 event->pending_wakeup = 0;
4999 perf_event_wakeup(event);
5003 perf_swevent_put_recursion_context(rctx);
5007 * We assume there is only KVM supporting the callbacks.
5008 * Later on, we might change it to a list if there is
5009 * another virtualization implementation supporting the callbacks.
5011 struct perf_guest_info_callbacks *perf_guest_cbs;
5013 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5015 perf_guest_cbs = cbs;
5018 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5020 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5022 perf_guest_cbs = NULL;
5025 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5028 perf_output_sample_regs(struct perf_output_handle *handle,
5029 struct pt_regs *regs, u64 mask)
5033 for_each_set_bit(bit, (const unsigned long *) &mask,
5034 sizeof(mask) * BITS_PER_BYTE) {
5037 val = perf_reg_value(regs, bit);
5038 perf_output_put(handle, val);
5042 static void perf_sample_regs_user(struct perf_regs *regs_user,
5043 struct pt_regs *regs,
5044 struct pt_regs *regs_user_copy)
5046 if (user_mode(regs)) {
5047 regs_user->abi = perf_reg_abi(current);
5048 regs_user->regs = regs;
5049 } else if (current->mm) {
5050 perf_get_regs_user(regs_user, regs, regs_user_copy);
5052 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5053 regs_user->regs = NULL;
5057 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5058 struct pt_regs *regs)
5060 regs_intr->regs = regs;
5061 regs_intr->abi = perf_reg_abi(current);
5066 * Get remaining task size from user stack pointer.
5068 * It'd be better to take stack vma map and limit this more
5069 * precisly, but there's no way to get it safely under interrupt,
5070 * so using TASK_SIZE as limit.
5072 static u64 perf_ustack_task_size(struct pt_regs *regs)
5074 unsigned long addr = perf_user_stack_pointer(regs);
5076 if (!addr || addr >= TASK_SIZE)
5079 return TASK_SIZE - addr;
5083 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5084 struct pt_regs *regs)
5088 /* No regs, no stack pointer, no dump. */
5093 * Check if we fit in with the requested stack size into the:
5095 * If we don't, we limit the size to the TASK_SIZE.
5097 * - remaining sample size
5098 * If we don't, we customize the stack size to
5099 * fit in to the remaining sample size.
5102 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5103 stack_size = min(stack_size, (u16) task_size);
5105 /* Current header size plus static size and dynamic size. */
5106 header_size += 2 * sizeof(u64);
5108 /* Do we fit in with the current stack dump size? */
5109 if ((u16) (header_size + stack_size) < header_size) {
5111 * If we overflow the maximum size for the sample,
5112 * we customize the stack dump size to fit in.
5114 stack_size = USHRT_MAX - header_size - sizeof(u64);
5115 stack_size = round_up(stack_size, sizeof(u64));
5122 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5123 struct pt_regs *regs)
5125 /* Case of a kernel thread, nothing to dump */
5128 perf_output_put(handle, size);
5137 * - the size requested by user or the best one we can fit
5138 * in to the sample max size
5140 * - user stack dump data
5142 * - the actual dumped size
5146 perf_output_put(handle, dump_size);
5149 sp = perf_user_stack_pointer(regs);
5150 rem = __output_copy_user(handle, (void *) sp, dump_size);
5151 dyn_size = dump_size - rem;
5153 perf_output_skip(handle, rem);
5156 perf_output_put(handle, dyn_size);
5160 static void __perf_event_header__init_id(struct perf_event_header *header,
5161 struct perf_sample_data *data,
5162 struct perf_event *event)
5164 u64 sample_type = event->attr.sample_type;
5166 data->type = sample_type;
5167 header->size += event->id_header_size;
5169 if (sample_type & PERF_SAMPLE_TID) {
5170 /* namespace issues */
5171 data->tid_entry.pid = perf_event_pid(event, current);
5172 data->tid_entry.tid = perf_event_tid(event, current);
5175 if (sample_type & PERF_SAMPLE_TIME)
5176 data->time = perf_event_clock(event);
5178 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5179 data->id = primary_event_id(event);
5181 if (sample_type & PERF_SAMPLE_STREAM_ID)
5182 data->stream_id = event->id;
5184 if (sample_type & PERF_SAMPLE_CPU) {
5185 data->cpu_entry.cpu = raw_smp_processor_id();
5186 data->cpu_entry.reserved = 0;
5190 void perf_event_header__init_id(struct perf_event_header *header,
5191 struct perf_sample_data *data,
5192 struct perf_event *event)
5194 if (event->attr.sample_id_all)
5195 __perf_event_header__init_id(header, data, event);
5198 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5199 struct perf_sample_data *data)
5201 u64 sample_type = data->type;
5203 if (sample_type & PERF_SAMPLE_TID)
5204 perf_output_put(handle, data->tid_entry);
5206 if (sample_type & PERF_SAMPLE_TIME)
5207 perf_output_put(handle, data->time);
5209 if (sample_type & PERF_SAMPLE_ID)
5210 perf_output_put(handle, data->id);
5212 if (sample_type & PERF_SAMPLE_STREAM_ID)
5213 perf_output_put(handle, data->stream_id);
5215 if (sample_type & PERF_SAMPLE_CPU)
5216 perf_output_put(handle, data->cpu_entry);
5218 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5219 perf_output_put(handle, data->id);
5222 void perf_event__output_id_sample(struct perf_event *event,
5223 struct perf_output_handle *handle,
5224 struct perf_sample_data *sample)
5226 if (event->attr.sample_id_all)
5227 __perf_event__output_id_sample(handle, sample);
5230 static void perf_output_read_one(struct perf_output_handle *handle,
5231 struct perf_event *event,
5232 u64 enabled, u64 running)
5234 u64 read_format = event->attr.read_format;
5238 values[n++] = perf_event_count(event);
5239 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5240 values[n++] = enabled +
5241 atomic64_read(&event->child_total_time_enabled);
5243 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5244 values[n++] = running +
5245 atomic64_read(&event->child_total_time_running);
5247 if (read_format & PERF_FORMAT_ID)
5248 values[n++] = primary_event_id(event);
5250 __output_copy(handle, values, n * sizeof(u64));
5254 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5256 static void perf_output_read_group(struct perf_output_handle *handle,
5257 struct perf_event *event,
5258 u64 enabled, u64 running)
5260 struct perf_event *leader = event->group_leader, *sub;
5261 u64 read_format = event->attr.read_format;
5265 values[n++] = 1 + leader->nr_siblings;
5267 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5268 values[n++] = enabled;
5270 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5271 values[n++] = running;
5273 if (leader != event)
5274 leader->pmu->read(leader);
5276 values[n++] = perf_event_count(leader);
5277 if (read_format & PERF_FORMAT_ID)
5278 values[n++] = primary_event_id(leader);
5280 __output_copy(handle, values, n * sizeof(u64));
5282 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5285 if ((sub != event) &&
5286 (sub->state == PERF_EVENT_STATE_ACTIVE))
5287 sub->pmu->read(sub);
5289 values[n++] = perf_event_count(sub);
5290 if (read_format & PERF_FORMAT_ID)
5291 values[n++] = primary_event_id(sub);
5293 __output_copy(handle, values, n * sizeof(u64));
5297 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5298 PERF_FORMAT_TOTAL_TIME_RUNNING)
5300 static void perf_output_read(struct perf_output_handle *handle,
5301 struct perf_event *event)
5303 u64 enabled = 0, running = 0, now;
5304 u64 read_format = event->attr.read_format;
5307 * compute total_time_enabled, total_time_running
5308 * based on snapshot values taken when the event
5309 * was last scheduled in.
5311 * we cannot simply called update_context_time()
5312 * because of locking issue as we are called in
5315 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5316 calc_timer_values(event, &now, &enabled, &running);
5318 if (event->attr.read_format & PERF_FORMAT_GROUP)
5319 perf_output_read_group(handle, event, enabled, running);
5321 perf_output_read_one(handle, event, enabled, running);
5324 void perf_output_sample(struct perf_output_handle *handle,
5325 struct perf_event_header *header,
5326 struct perf_sample_data *data,
5327 struct perf_event *event)
5329 u64 sample_type = data->type;
5331 perf_output_put(handle, *header);
5333 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5334 perf_output_put(handle, data->id);
5336 if (sample_type & PERF_SAMPLE_IP)
5337 perf_output_put(handle, data->ip);
5339 if (sample_type & PERF_SAMPLE_TID)
5340 perf_output_put(handle, data->tid_entry);
5342 if (sample_type & PERF_SAMPLE_TIME)
5343 perf_output_put(handle, data->time);
5345 if (sample_type & PERF_SAMPLE_ADDR)
5346 perf_output_put(handle, data->addr);
5348 if (sample_type & PERF_SAMPLE_ID)
5349 perf_output_put(handle, data->id);
5351 if (sample_type & PERF_SAMPLE_STREAM_ID)
5352 perf_output_put(handle, data->stream_id);
5354 if (sample_type & PERF_SAMPLE_CPU)
5355 perf_output_put(handle, data->cpu_entry);
5357 if (sample_type & PERF_SAMPLE_PERIOD)
5358 perf_output_put(handle, data->period);
5360 if (sample_type & PERF_SAMPLE_READ)
5361 perf_output_read(handle, event);
5363 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5364 if (data->callchain) {
5367 if (data->callchain)
5368 size += data->callchain->nr;
5370 size *= sizeof(u64);
5372 __output_copy(handle, data->callchain, size);
5375 perf_output_put(handle, nr);
5379 if (sample_type & PERF_SAMPLE_RAW) {
5381 u32 raw_size = data->raw->size;
5382 u32 real_size = round_up(raw_size + sizeof(u32),
5383 sizeof(u64)) - sizeof(u32);
5386 perf_output_put(handle, real_size);
5387 __output_copy(handle, data->raw->data, raw_size);
5388 if (real_size - raw_size)
5389 __output_copy(handle, &zero, real_size - raw_size);
5395 .size = sizeof(u32),
5398 perf_output_put(handle, raw);
5402 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5403 if (data->br_stack) {
5406 size = data->br_stack->nr
5407 * sizeof(struct perf_branch_entry);
5409 perf_output_put(handle, data->br_stack->nr);
5410 perf_output_copy(handle, data->br_stack->entries, size);
5413 * we always store at least the value of nr
5416 perf_output_put(handle, nr);
5420 if (sample_type & PERF_SAMPLE_REGS_USER) {
5421 u64 abi = data->regs_user.abi;
5424 * If there are no regs to dump, notice it through
5425 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5427 perf_output_put(handle, abi);
5430 u64 mask = event->attr.sample_regs_user;
5431 perf_output_sample_regs(handle,
5432 data->regs_user.regs,
5437 if (sample_type & PERF_SAMPLE_STACK_USER) {
5438 perf_output_sample_ustack(handle,
5439 data->stack_user_size,
5440 data->regs_user.regs);
5443 if (sample_type & PERF_SAMPLE_WEIGHT)
5444 perf_output_put(handle, data->weight);
5446 if (sample_type & PERF_SAMPLE_DATA_SRC)
5447 perf_output_put(handle, data->data_src.val);
5449 if (sample_type & PERF_SAMPLE_TRANSACTION)
5450 perf_output_put(handle, data->txn);
5452 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5453 u64 abi = data->regs_intr.abi;
5455 * If there are no regs to dump, notice it through
5456 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5458 perf_output_put(handle, abi);
5461 u64 mask = event->attr.sample_regs_intr;
5463 perf_output_sample_regs(handle,
5464 data->regs_intr.regs,
5469 if (!event->attr.watermark) {
5470 int wakeup_events = event->attr.wakeup_events;
5472 if (wakeup_events) {
5473 struct ring_buffer *rb = handle->rb;
5474 int events = local_inc_return(&rb->events);
5476 if (events >= wakeup_events) {
5477 local_sub(wakeup_events, &rb->events);
5478 local_inc(&rb->wakeup);
5484 void perf_prepare_sample(struct perf_event_header *header,
5485 struct perf_sample_data *data,
5486 struct perf_event *event,
5487 struct pt_regs *regs)
5489 u64 sample_type = event->attr.sample_type;
5491 header->type = PERF_RECORD_SAMPLE;
5492 header->size = sizeof(*header) + event->header_size;
5495 header->misc |= perf_misc_flags(regs);
5497 __perf_event_header__init_id(header, data, event);
5499 if (sample_type & PERF_SAMPLE_IP)
5500 data->ip = perf_instruction_pointer(regs);
5502 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5505 data->callchain = perf_callchain(event, regs);
5507 if (data->callchain)
5508 size += data->callchain->nr;
5510 header->size += size * sizeof(u64);
5513 if (sample_type & PERF_SAMPLE_RAW) {
5514 int size = sizeof(u32);
5517 size += data->raw->size;
5519 size += sizeof(u32);
5521 header->size += round_up(size, sizeof(u64));
5524 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5525 int size = sizeof(u64); /* nr */
5526 if (data->br_stack) {
5527 size += data->br_stack->nr
5528 * sizeof(struct perf_branch_entry);
5530 header->size += size;
5533 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5534 perf_sample_regs_user(&data->regs_user, regs,
5535 &data->regs_user_copy);
5537 if (sample_type & PERF_SAMPLE_REGS_USER) {
5538 /* regs dump ABI info */
5539 int size = sizeof(u64);
5541 if (data->regs_user.regs) {
5542 u64 mask = event->attr.sample_regs_user;
5543 size += hweight64(mask) * sizeof(u64);
5546 header->size += size;
5549 if (sample_type & PERF_SAMPLE_STACK_USER) {
5551 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5552 * processed as the last one or have additional check added
5553 * in case new sample type is added, because we could eat
5554 * up the rest of the sample size.
5556 u16 stack_size = event->attr.sample_stack_user;
5557 u16 size = sizeof(u64);
5559 stack_size = perf_sample_ustack_size(stack_size, header->size,
5560 data->regs_user.regs);
5563 * If there is something to dump, add space for the dump
5564 * itself and for the field that tells the dynamic size,
5565 * which is how many have been actually dumped.
5568 size += sizeof(u64) + stack_size;
5570 data->stack_user_size = stack_size;
5571 header->size += size;
5574 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5575 /* regs dump ABI info */
5576 int size = sizeof(u64);
5578 perf_sample_regs_intr(&data->regs_intr, regs);
5580 if (data->regs_intr.regs) {
5581 u64 mask = event->attr.sample_regs_intr;
5583 size += hweight64(mask) * sizeof(u64);
5586 header->size += size;
5590 void perf_event_output(struct perf_event *event,
5591 struct perf_sample_data *data,
5592 struct pt_regs *regs)
5594 struct perf_output_handle handle;
5595 struct perf_event_header header;
5597 /* protect the callchain buffers */
5600 perf_prepare_sample(&header, data, event, regs);
5602 if (perf_output_begin(&handle, event, header.size))
5605 perf_output_sample(&handle, &header, data, event);
5607 perf_output_end(&handle);
5617 struct perf_read_event {
5618 struct perf_event_header header;
5625 perf_event_read_event(struct perf_event *event,
5626 struct task_struct *task)
5628 struct perf_output_handle handle;
5629 struct perf_sample_data sample;
5630 struct perf_read_event read_event = {
5632 .type = PERF_RECORD_READ,
5634 .size = sizeof(read_event) + event->read_size,
5636 .pid = perf_event_pid(event, task),
5637 .tid = perf_event_tid(event, task),
5641 perf_event_header__init_id(&read_event.header, &sample, event);
5642 ret = perf_output_begin(&handle, event, read_event.header.size);
5646 perf_output_put(&handle, read_event);
5647 perf_output_read(&handle, event);
5648 perf_event__output_id_sample(event, &handle, &sample);
5650 perf_output_end(&handle);
5653 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5656 perf_event_aux_ctx(struct perf_event_context *ctx,
5657 perf_event_aux_output_cb output,
5660 struct perf_event *event;
5662 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5663 if (event->state < PERF_EVENT_STATE_INACTIVE)
5665 if (!event_filter_match(event))
5667 output(event, data);
5672 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5673 struct perf_event_context *task_ctx)
5677 perf_event_aux_ctx(task_ctx, output, data);
5683 perf_event_aux(perf_event_aux_output_cb output, void *data,
5684 struct perf_event_context *task_ctx)
5686 struct perf_cpu_context *cpuctx;
5687 struct perf_event_context *ctx;
5692 * If we have task_ctx != NULL we only notify
5693 * the task context itself. The task_ctx is set
5694 * only for EXIT events before releasing task
5698 perf_event_aux_task_ctx(output, data, task_ctx);
5703 list_for_each_entry_rcu(pmu, &pmus, entry) {
5704 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5705 if (cpuctx->unique_pmu != pmu)
5707 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5708 ctxn = pmu->task_ctx_nr;
5711 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5713 perf_event_aux_ctx(ctx, output, data);
5715 put_cpu_ptr(pmu->pmu_cpu_context);
5721 * task tracking -- fork/exit
5723 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5726 struct perf_task_event {
5727 struct task_struct *task;
5728 struct perf_event_context *task_ctx;
5731 struct perf_event_header header;
5741 static int perf_event_task_match(struct perf_event *event)
5743 return event->attr.comm || event->attr.mmap ||
5744 event->attr.mmap2 || event->attr.mmap_data ||
5748 static void perf_event_task_output(struct perf_event *event,
5751 struct perf_task_event *task_event = data;
5752 struct perf_output_handle handle;
5753 struct perf_sample_data sample;
5754 struct task_struct *task = task_event->task;
5755 int ret, size = task_event->event_id.header.size;
5757 if (!perf_event_task_match(event))
5760 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5762 ret = perf_output_begin(&handle, event,
5763 task_event->event_id.header.size);
5767 task_event->event_id.pid = perf_event_pid(event, task);
5768 task_event->event_id.ppid = perf_event_pid(event, current);
5770 task_event->event_id.tid = perf_event_tid(event, task);
5771 task_event->event_id.ptid = perf_event_tid(event, current);
5773 task_event->event_id.time = perf_event_clock(event);
5775 perf_output_put(&handle, task_event->event_id);
5777 perf_event__output_id_sample(event, &handle, &sample);
5779 perf_output_end(&handle);
5781 task_event->event_id.header.size = size;
5784 static void perf_event_task(struct task_struct *task,
5785 struct perf_event_context *task_ctx,
5788 struct perf_task_event task_event;
5790 if (!atomic_read(&nr_comm_events) &&
5791 !atomic_read(&nr_mmap_events) &&
5792 !atomic_read(&nr_task_events))
5795 task_event = (struct perf_task_event){
5797 .task_ctx = task_ctx,
5800 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5802 .size = sizeof(task_event.event_id),
5812 perf_event_aux(perf_event_task_output,
5817 void perf_event_fork(struct task_struct *task)
5819 perf_event_task(task, NULL, 1);
5826 struct perf_comm_event {
5827 struct task_struct *task;
5832 struct perf_event_header header;
5839 static int perf_event_comm_match(struct perf_event *event)
5841 return event->attr.comm;
5844 static void perf_event_comm_output(struct perf_event *event,
5847 struct perf_comm_event *comm_event = data;
5848 struct perf_output_handle handle;
5849 struct perf_sample_data sample;
5850 int size = comm_event->event_id.header.size;
5853 if (!perf_event_comm_match(event))
5856 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5857 ret = perf_output_begin(&handle, event,
5858 comm_event->event_id.header.size);
5863 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5864 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5866 perf_output_put(&handle, comm_event->event_id);
5867 __output_copy(&handle, comm_event->comm,
5868 comm_event->comm_size);
5870 perf_event__output_id_sample(event, &handle, &sample);
5872 perf_output_end(&handle);
5874 comm_event->event_id.header.size = size;
5877 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5879 char comm[TASK_COMM_LEN];
5882 memset(comm, 0, sizeof(comm));
5883 strlcpy(comm, comm_event->task->comm, sizeof(comm));
5884 size = ALIGN(strlen(comm)+1, sizeof(u64));
5886 comm_event->comm = comm;
5887 comm_event->comm_size = size;
5889 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
5891 perf_event_aux(perf_event_comm_output,
5896 void perf_event_comm(struct task_struct *task, bool exec)
5898 struct perf_comm_event comm_event;
5900 if (!atomic_read(&nr_comm_events))
5903 comm_event = (struct perf_comm_event){
5909 .type = PERF_RECORD_COMM,
5910 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
5918 perf_event_comm_event(&comm_event);
5925 struct perf_mmap_event {
5926 struct vm_area_struct *vma;
5928 const char *file_name;
5936 struct perf_event_header header;
5946 static int perf_event_mmap_match(struct perf_event *event,
5949 struct perf_mmap_event *mmap_event = data;
5950 struct vm_area_struct *vma = mmap_event->vma;
5951 int executable = vma->vm_flags & VM_EXEC;
5953 return (!executable && event->attr.mmap_data) ||
5954 (executable && (event->attr.mmap || event->attr.mmap2));
5957 static void perf_event_mmap_output(struct perf_event *event,
5960 struct perf_mmap_event *mmap_event = data;
5961 struct perf_output_handle handle;
5962 struct perf_sample_data sample;
5963 int size = mmap_event->event_id.header.size;
5966 if (!perf_event_mmap_match(event, data))
5969 if (event->attr.mmap2) {
5970 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
5971 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
5972 mmap_event->event_id.header.size += sizeof(mmap_event->min);
5973 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
5974 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
5975 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
5976 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
5979 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
5980 ret = perf_output_begin(&handle, event,
5981 mmap_event->event_id.header.size);
5985 mmap_event->event_id.pid = perf_event_pid(event, current);
5986 mmap_event->event_id.tid = perf_event_tid(event, current);
5988 perf_output_put(&handle, mmap_event->event_id);
5990 if (event->attr.mmap2) {
5991 perf_output_put(&handle, mmap_event->maj);
5992 perf_output_put(&handle, mmap_event->min);
5993 perf_output_put(&handle, mmap_event->ino);
5994 perf_output_put(&handle, mmap_event->ino_generation);
5995 perf_output_put(&handle, mmap_event->prot);
5996 perf_output_put(&handle, mmap_event->flags);
5999 __output_copy(&handle, mmap_event->file_name,
6000 mmap_event->file_size);
6002 perf_event__output_id_sample(event, &handle, &sample);
6004 perf_output_end(&handle);
6006 mmap_event->event_id.header.size = size;
6009 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6011 struct vm_area_struct *vma = mmap_event->vma;
6012 struct file *file = vma->vm_file;
6013 int maj = 0, min = 0;
6014 u64 ino = 0, gen = 0;
6015 u32 prot = 0, flags = 0;
6022 struct inode *inode;
6025 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6031 * d_path() works from the end of the rb backwards, so we
6032 * need to add enough zero bytes after the string to handle
6033 * the 64bit alignment we do later.
6035 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6040 inode = file_inode(vma->vm_file);
6041 dev = inode->i_sb->s_dev;
6043 gen = inode->i_generation;
6047 if (vma->vm_flags & VM_READ)
6049 if (vma->vm_flags & VM_WRITE)
6051 if (vma->vm_flags & VM_EXEC)
6054 if (vma->vm_flags & VM_MAYSHARE)
6057 flags = MAP_PRIVATE;
6059 if (vma->vm_flags & VM_DENYWRITE)
6060 flags |= MAP_DENYWRITE;
6061 if (vma->vm_flags & VM_MAYEXEC)
6062 flags |= MAP_EXECUTABLE;
6063 if (vma->vm_flags & VM_LOCKED)
6064 flags |= MAP_LOCKED;
6065 if (vma->vm_flags & VM_HUGETLB)
6066 flags |= MAP_HUGETLB;
6070 if (vma->vm_ops && vma->vm_ops->name) {
6071 name = (char *) vma->vm_ops->name(vma);
6076 name = (char *)arch_vma_name(vma);
6080 if (vma->vm_start <= vma->vm_mm->start_brk &&
6081 vma->vm_end >= vma->vm_mm->brk) {
6085 if (vma->vm_start <= vma->vm_mm->start_stack &&
6086 vma->vm_end >= vma->vm_mm->start_stack) {
6096 strlcpy(tmp, name, sizeof(tmp));
6100 * Since our buffer works in 8 byte units we need to align our string
6101 * size to a multiple of 8. However, we must guarantee the tail end is
6102 * zero'd out to avoid leaking random bits to userspace.
6104 size = strlen(name)+1;
6105 while (!IS_ALIGNED(size, sizeof(u64)))
6106 name[size++] = '\0';
6108 mmap_event->file_name = name;
6109 mmap_event->file_size = size;
6110 mmap_event->maj = maj;
6111 mmap_event->min = min;
6112 mmap_event->ino = ino;
6113 mmap_event->ino_generation = gen;
6114 mmap_event->prot = prot;
6115 mmap_event->flags = flags;
6117 if (!(vma->vm_flags & VM_EXEC))
6118 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6120 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6122 perf_event_aux(perf_event_mmap_output,
6129 void perf_event_mmap(struct vm_area_struct *vma)
6131 struct perf_mmap_event mmap_event;
6133 if (!atomic_read(&nr_mmap_events))
6136 mmap_event = (struct perf_mmap_event){
6142 .type = PERF_RECORD_MMAP,
6143 .misc = PERF_RECORD_MISC_USER,
6148 .start = vma->vm_start,
6149 .len = vma->vm_end - vma->vm_start,
6150 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6152 /* .maj (attr_mmap2 only) */
6153 /* .min (attr_mmap2 only) */
6154 /* .ino (attr_mmap2 only) */
6155 /* .ino_generation (attr_mmap2 only) */
6156 /* .prot (attr_mmap2 only) */
6157 /* .flags (attr_mmap2 only) */
6160 perf_event_mmap_event(&mmap_event);
6163 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6164 unsigned long size, u64 flags)
6166 struct perf_output_handle handle;
6167 struct perf_sample_data sample;
6168 struct perf_aux_event {
6169 struct perf_event_header header;
6175 .type = PERF_RECORD_AUX,
6177 .size = sizeof(rec),
6185 perf_event_header__init_id(&rec.header, &sample, event);
6186 ret = perf_output_begin(&handle, event, rec.header.size);
6191 perf_output_put(&handle, rec);
6192 perf_event__output_id_sample(event, &handle, &sample);
6194 perf_output_end(&handle);
6198 * Lost/dropped samples logging
6200 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6202 struct perf_output_handle handle;
6203 struct perf_sample_data sample;
6207 struct perf_event_header header;
6209 } lost_samples_event = {
6211 .type = PERF_RECORD_LOST_SAMPLES,
6213 .size = sizeof(lost_samples_event),
6218 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6220 ret = perf_output_begin(&handle, event,
6221 lost_samples_event.header.size);
6225 perf_output_put(&handle, lost_samples_event);
6226 perf_event__output_id_sample(event, &handle, &sample);
6227 perf_output_end(&handle);
6231 * context_switch tracking
6234 struct perf_switch_event {
6235 struct task_struct *task;
6236 struct task_struct *next_prev;
6239 struct perf_event_header header;
6245 static int perf_event_switch_match(struct perf_event *event)
6247 return event->attr.context_switch;
6250 static void perf_event_switch_output(struct perf_event *event, void *data)
6252 struct perf_switch_event *se = data;
6253 struct perf_output_handle handle;
6254 struct perf_sample_data sample;
6257 if (!perf_event_switch_match(event))
6260 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6261 if (event->ctx->task) {
6262 se->event_id.header.type = PERF_RECORD_SWITCH;
6263 se->event_id.header.size = sizeof(se->event_id.header);
6265 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6266 se->event_id.header.size = sizeof(se->event_id);
6267 se->event_id.next_prev_pid =
6268 perf_event_pid(event, se->next_prev);
6269 se->event_id.next_prev_tid =
6270 perf_event_tid(event, se->next_prev);
6273 perf_event_header__init_id(&se->event_id.header, &sample, event);
6275 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6279 if (event->ctx->task)
6280 perf_output_put(&handle, se->event_id.header);
6282 perf_output_put(&handle, se->event_id);
6284 perf_event__output_id_sample(event, &handle, &sample);
6286 perf_output_end(&handle);
6289 static void perf_event_switch(struct task_struct *task,
6290 struct task_struct *next_prev, bool sched_in)
6292 struct perf_switch_event switch_event;
6294 /* N.B. caller checks nr_switch_events != 0 */
6296 switch_event = (struct perf_switch_event){
6298 .next_prev = next_prev,
6302 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6305 /* .next_prev_pid */
6306 /* .next_prev_tid */
6310 perf_event_aux(perf_event_switch_output,
6316 * IRQ throttle logging
6319 static void perf_log_throttle(struct perf_event *event, int enable)
6321 struct perf_output_handle handle;
6322 struct perf_sample_data sample;
6326 struct perf_event_header header;
6330 } throttle_event = {
6332 .type = PERF_RECORD_THROTTLE,
6334 .size = sizeof(throttle_event),
6336 .time = perf_event_clock(event),
6337 .id = primary_event_id(event),
6338 .stream_id = event->id,
6342 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6344 perf_event_header__init_id(&throttle_event.header, &sample, event);
6346 ret = perf_output_begin(&handle, event,
6347 throttle_event.header.size);
6351 perf_output_put(&handle, throttle_event);
6352 perf_event__output_id_sample(event, &handle, &sample);
6353 perf_output_end(&handle);
6356 static void perf_log_itrace_start(struct perf_event *event)
6358 struct perf_output_handle handle;
6359 struct perf_sample_data sample;
6360 struct perf_aux_event {
6361 struct perf_event_header header;
6368 event = event->parent;
6370 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6371 event->hw.itrace_started)
6374 rec.header.type = PERF_RECORD_ITRACE_START;
6375 rec.header.misc = 0;
6376 rec.header.size = sizeof(rec);
6377 rec.pid = perf_event_pid(event, current);
6378 rec.tid = perf_event_tid(event, current);
6380 perf_event_header__init_id(&rec.header, &sample, event);
6381 ret = perf_output_begin(&handle, event, rec.header.size);
6386 perf_output_put(&handle, rec);
6387 perf_event__output_id_sample(event, &handle, &sample);
6389 perf_output_end(&handle);
6393 * Generic event overflow handling, sampling.
6396 static int __perf_event_overflow(struct perf_event *event,
6397 int throttle, struct perf_sample_data *data,
6398 struct pt_regs *regs)
6400 int events = atomic_read(&event->event_limit);
6401 struct hw_perf_event *hwc = &event->hw;
6406 * Non-sampling counters might still use the PMI to fold short
6407 * hardware counters, ignore those.
6409 if (unlikely(!is_sampling_event(event)))
6412 seq = __this_cpu_read(perf_throttled_seq);
6413 if (seq != hwc->interrupts_seq) {
6414 hwc->interrupts_seq = seq;
6415 hwc->interrupts = 1;
6418 if (unlikely(throttle
6419 && hwc->interrupts >= max_samples_per_tick)) {
6420 __this_cpu_inc(perf_throttled_count);
6421 hwc->interrupts = MAX_INTERRUPTS;
6422 perf_log_throttle(event, 0);
6423 tick_nohz_full_kick();
6428 if (event->attr.freq) {
6429 u64 now = perf_clock();
6430 s64 delta = now - hwc->freq_time_stamp;
6432 hwc->freq_time_stamp = now;
6434 if (delta > 0 && delta < 2*TICK_NSEC)
6435 perf_adjust_period(event, delta, hwc->last_period, true);
6439 * XXX event_limit might not quite work as expected on inherited
6443 event->pending_kill = POLL_IN;
6444 if (events && atomic_dec_and_test(&event->event_limit)) {
6446 event->pending_kill = POLL_HUP;
6447 event->pending_disable = 1;
6448 irq_work_queue(&event->pending);
6451 if (event->overflow_handler)
6452 event->overflow_handler(event, data, regs);
6454 perf_event_output(event, data, regs);
6456 if (*perf_event_fasync(event) && event->pending_kill) {
6457 event->pending_wakeup = 1;
6458 irq_work_queue(&event->pending);
6464 int perf_event_overflow(struct perf_event *event,
6465 struct perf_sample_data *data,
6466 struct pt_regs *regs)
6468 return __perf_event_overflow(event, 1, data, regs);
6472 * Generic software event infrastructure
6475 struct swevent_htable {
6476 struct swevent_hlist *swevent_hlist;
6477 struct mutex hlist_mutex;
6480 /* Recursion avoidance in each contexts */
6481 int recursion[PERF_NR_CONTEXTS];
6484 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6487 * We directly increment event->count and keep a second value in
6488 * event->hw.period_left to count intervals. This period event
6489 * is kept in the range [-sample_period, 0] so that we can use the
6493 u64 perf_swevent_set_period(struct perf_event *event)
6495 struct hw_perf_event *hwc = &event->hw;
6496 u64 period = hwc->last_period;
6500 hwc->last_period = hwc->sample_period;
6503 old = val = local64_read(&hwc->period_left);
6507 nr = div64_u64(period + val, period);
6508 offset = nr * period;
6510 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6516 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6517 struct perf_sample_data *data,
6518 struct pt_regs *regs)
6520 struct hw_perf_event *hwc = &event->hw;
6524 overflow = perf_swevent_set_period(event);
6526 if (hwc->interrupts == MAX_INTERRUPTS)
6529 for (; overflow; overflow--) {
6530 if (__perf_event_overflow(event, throttle,
6533 * We inhibit the overflow from happening when
6534 * hwc->interrupts == MAX_INTERRUPTS.
6542 static void perf_swevent_event(struct perf_event *event, u64 nr,
6543 struct perf_sample_data *data,
6544 struct pt_regs *regs)
6546 struct hw_perf_event *hwc = &event->hw;
6548 local64_add(nr, &event->count);
6553 if (!is_sampling_event(event))
6556 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6558 return perf_swevent_overflow(event, 1, data, regs);
6560 data->period = event->hw.last_period;
6562 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6563 return perf_swevent_overflow(event, 1, data, regs);
6565 if (local64_add_negative(nr, &hwc->period_left))
6568 perf_swevent_overflow(event, 0, data, regs);
6571 static int perf_exclude_event(struct perf_event *event,
6572 struct pt_regs *regs)
6574 if (event->hw.state & PERF_HES_STOPPED)
6578 if (event->attr.exclude_user && user_mode(regs))
6581 if (event->attr.exclude_kernel && !user_mode(regs))
6588 static int perf_swevent_match(struct perf_event *event,
6589 enum perf_type_id type,
6591 struct perf_sample_data *data,
6592 struct pt_regs *regs)
6594 if (event->attr.type != type)
6597 if (event->attr.config != event_id)
6600 if (perf_exclude_event(event, regs))
6606 static inline u64 swevent_hash(u64 type, u32 event_id)
6608 u64 val = event_id | (type << 32);
6610 return hash_64(val, SWEVENT_HLIST_BITS);
6613 static inline struct hlist_head *
6614 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6616 u64 hash = swevent_hash(type, event_id);
6618 return &hlist->heads[hash];
6621 /* For the read side: events when they trigger */
6622 static inline struct hlist_head *
6623 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6625 struct swevent_hlist *hlist;
6627 hlist = rcu_dereference(swhash->swevent_hlist);
6631 return __find_swevent_head(hlist, type, event_id);
6634 /* For the event head insertion and removal in the hlist */
6635 static inline struct hlist_head *
6636 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6638 struct swevent_hlist *hlist;
6639 u32 event_id = event->attr.config;
6640 u64 type = event->attr.type;
6643 * Event scheduling is always serialized against hlist allocation
6644 * and release. Which makes the protected version suitable here.
6645 * The context lock guarantees that.
6647 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6648 lockdep_is_held(&event->ctx->lock));
6652 return __find_swevent_head(hlist, type, event_id);
6655 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6657 struct perf_sample_data *data,
6658 struct pt_regs *regs)
6660 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6661 struct perf_event *event;
6662 struct hlist_head *head;
6665 head = find_swevent_head_rcu(swhash, type, event_id);
6669 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6670 if (perf_swevent_match(event, type, event_id, data, regs))
6671 perf_swevent_event(event, nr, data, regs);
6677 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6679 int perf_swevent_get_recursion_context(void)
6681 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6683 return get_recursion_context(swhash->recursion);
6685 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6687 inline void perf_swevent_put_recursion_context(int rctx)
6689 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6691 put_recursion_context(swhash->recursion, rctx);
6694 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6696 struct perf_sample_data data;
6698 if (WARN_ON_ONCE(!regs))
6701 perf_sample_data_init(&data, addr, 0);
6702 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6705 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6709 preempt_disable_notrace();
6710 rctx = perf_swevent_get_recursion_context();
6711 if (unlikely(rctx < 0))
6714 ___perf_sw_event(event_id, nr, regs, addr);
6716 perf_swevent_put_recursion_context(rctx);
6718 preempt_enable_notrace();
6721 static void perf_swevent_read(struct perf_event *event)
6725 static int perf_swevent_add(struct perf_event *event, int flags)
6727 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6728 struct hw_perf_event *hwc = &event->hw;
6729 struct hlist_head *head;
6731 if (is_sampling_event(event)) {
6732 hwc->last_period = hwc->sample_period;
6733 perf_swevent_set_period(event);
6736 hwc->state = !(flags & PERF_EF_START);
6738 head = find_swevent_head(swhash, event);
6739 if (WARN_ON_ONCE(!head))
6742 hlist_add_head_rcu(&event->hlist_entry, head);
6743 perf_event_update_userpage(event);
6748 static void perf_swevent_del(struct perf_event *event, int flags)
6750 hlist_del_rcu(&event->hlist_entry);
6753 static void perf_swevent_start(struct perf_event *event, int flags)
6755 event->hw.state = 0;
6758 static void perf_swevent_stop(struct perf_event *event, int flags)
6760 event->hw.state = PERF_HES_STOPPED;
6763 /* Deref the hlist from the update side */
6764 static inline struct swevent_hlist *
6765 swevent_hlist_deref(struct swevent_htable *swhash)
6767 return rcu_dereference_protected(swhash->swevent_hlist,
6768 lockdep_is_held(&swhash->hlist_mutex));
6771 static void swevent_hlist_release(struct swevent_htable *swhash)
6773 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6778 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6779 kfree_rcu(hlist, rcu_head);
6782 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6784 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6786 mutex_lock(&swhash->hlist_mutex);
6788 if (!--swhash->hlist_refcount)
6789 swevent_hlist_release(swhash);
6791 mutex_unlock(&swhash->hlist_mutex);
6794 static void swevent_hlist_put(struct perf_event *event)
6798 for_each_possible_cpu(cpu)
6799 swevent_hlist_put_cpu(event, cpu);
6802 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6804 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6807 mutex_lock(&swhash->hlist_mutex);
6808 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6809 struct swevent_hlist *hlist;
6811 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6816 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6818 swhash->hlist_refcount++;
6820 mutex_unlock(&swhash->hlist_mutex);
6825 static int swevent_hlist_get(struct perf_event *event)
6828 int cpu, failed_cpu;
6831 for_each_possible_cpu(cpu) {
6832 err = swevent_hlist_get_cpu(event, cpu);
6842 for_each_possible_cpu(cpu) {
6843 if (cpu == failed_cpu)
6845 swevent_hlist_put_cpu(event, cpu);
6852 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6854 static void sw_perf_event_destroy(struct perf_event *event)
6856 u64 event_id = event->attr.config;
6858 WARN_ON(event->parent);
6860 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6861 swevent_hlist_put(event);
6864 static int perf_swevent_init(struct perf_event *event)
6866 u64 event_id = event->attr.config;
6868 if (event->attr.type != PERF_TYPE_SOFTWARE)
6872 * no branch sampling for software events
6874 if (has_branch_stack(event))
6878 case PERF_COUNT_SW_CPU_CLOCK:
6879 case PERF_COUNT_SW_TASK_CLOCK:
6886 if (event_id >= PERF_COUNT_SW_MAX)
6889 if (!event->parent) {
6892 err = swevent_hlist_get(event);
6896 static_key_slow_inc(&perf_swevent_enabled[event_id]);
6897 event->destroy = sw_perf_event_destroy;
6903 static struct pmu perf_swevent = {
6904 .task_ctx_nr = perf_sw_context,
6906 .capabilities = PERF_PMU_CAP_NO_NMI,
6908 .event_init = perf_swevent_init,
6909 .add = perf_swevent_add,
6910 .del = perf_swevent_del,
6911 .start = perf_swevent_start,
6912 .stop = perf_swevent_stop,
6913 .read = perf_swevent_read,
6916 #ifdef CONFIG_EVENT_TRACING
6918 static int perf_tp_filter_match(struct perf_event *event,
6919 struct perf_sample_data *data)
6921 void *record = data->raw->data;
6923 /* only top level events have filters set */
6925 event = event->parent;
6927 if (likely(!event->filter) || filter_match_preds(event->filter, record))
6932 static int perf_tp_event_match(struct perf_event *event,
6933 struct perf_sample_data *data,
6934 struct pt_regs *regs)
6936 if (event->hw.state & PERF_HES_STOPPED)
6939 * All tracepoints are from kernel-space.
6941 if (event->attr.exclude_kernel)
6944 if (!perf_tp_filter_match(event, data))
6950 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
6951 struct pt_regs *regs, struct hlist_head *head, int rctx,
6952 struct task_struct *task)
6954 struct perf_sample_data data;
6955 struct perf_event *event;
6957 struct perf_raw_record raw = {
6962 perf_sample_data_init(&data, addr, 0);
6965 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6966 if (perf_tp_event_match(event, &data, regs))
6967 perf_swevent_event(event, count, &data, regs);
6971 * If we got specified a target task, also iterate its context and
6972 * deliver this event there too.
6974 if (task && task != current) {
6975 struct perf_event_context *ctx;
6976 struct trace_entry *entry = record;
6979 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
6983 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6984 if (event->attr.type != PERF_TYPE_TRACEPOINT)
6986 if (event->attr.config != entry->type)
6988 if (perf_tp_event_match(event, &data, regs))
6989 perf_swevent_event(event, count, &data, regs);
6995 perf_swevent_put_recursion_context(rctx);
6997 EXPORT_SYMBOL_GPL(perf_tp_event);
6999 static void tp_perf_event_destroy(struct perf_event *event)
7001 perf_trace_destroy(event);
7004 static int perf_tp_event_init(struct perf_event *event)
7008 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7012 * no branch sampling for tracepoint events
7014 if (has_branch_stack(event))
7017 err = perf_trace_init(event);
7021 event->destroy = tp_perf_event_destroy;
7026 static struct pmu perf_tracepoint = {
7027 .task_ctx_nr = perf_sw_context,
7029 .event_init = perf_tp_event_init,
7030 .add = perf_trace_add,
7031 .del = perf_trace_del,
7032 .start = perf_swevent_start,
7033 .stop = perf_swevent_stop,
7034 .read = perf_swevent_read,
7037 static inline void perf_tp_register(void)
7039 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7042 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7047 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7050 filter_str = strndup_user(arg, PAGE_SIZE);
7051 if (IS_ERR(filter_str))
7052 return PTR_ERR(filter_str);
7054 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7060 static void perf_event_free_filter(struct perf_event *event)
7062 ftrace_profile_free_filter(event);
7065 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7067 struct bpf_prog *prog;
7069 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7072 if (event->tp_event->prog)
7075 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7076 /* bpf programs can only be attached to u/kprobes */
7079 prog = bpf_prog_get(prog_fd);
7081 return PTR_ERR(prog);
7083 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7084 /* valid fd, but invalid bpf program type */
7089 event->tp_event->prog = prog;
7094 static void perf_event_free_bpf_prog(struct perf_event *event)
7096 struct bpf_prog *prog;
7098 if (!event->tp_event)
7101 prog = event->tp_event->prog;
7103 event->tp_event->prog = NULL;
7104 bpf_prog_put_rcu(prog);
7110 static inline void perf_tp_register(void)
7114 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7119 static void perf_event_free_filter(struct perf_event *event)
7123 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7128 static void perf_event_free_bpf_prog(struct perf_event *event)
7131 #endif /* CONFIG_EVENT_TRACING */
7133 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7134 void perf_bp_event(struct perf_event *bp, void *data)
7136 struct perf_sample_data sample;
7137 struct pt_regs *regs = data;
7139 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7141 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7142 perf_swevent_event(bp, 1, &sample, regs);
7147 * hrtimer based swevent callback
7150 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7152 enum hrtimer_restart ret = HRTIMER_RESTART;
7153 struct perf_sample_data data;
7154 struct pt_regs *regs;
7155 struct perf_event *event;
7158 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7160 if (event->state != PERF_EVENT_STATE_ACTIVE)
7161 return HRTIMER_NORESTART;
7163 event->pmu->read(event);
7165 perf_sample_data_init(&data, 0, event->hw.last_period);
7166 regs = get_irq_regs();
7168 if (regs && !perf_exclude_event(event, regs)) {
7169 if (!(event->attr.exclude_idle && is_idle_task(current)))
7170 if (__perf_event_overflow(event, 1, &data, regs))
7171 ret = HRTIMER_NORESTART;
7174 period = max_t(u64, 10000, event->hw.sample_period);
7175 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7180 static void perf_swevent_start_hrtimer(struct perf_event *event)
7182 struct hw_perf_event *hwc = &event->hw;
7185 if (!is_sampling_event(event))
7188 period = local64_read(&hwc->period_left);
7193 local64_set(&hwc->period_left, 0);
7195 period = max_t(u64, 10000, hwc->sample_period);
7197 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7198 HRTIMER_MODE_REL_PINNED);
7201 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7203 struct hw_perf_event *hwc = &event->hw;
7205 if (is_sampling_event(event)) {
7206 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7207 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7209 hrtimer_cancel(&hwc->hrtimer);
7213 static void perf_swevent_init_hrtimer(struct perf_event *event)
7215 struct hw_perf_event *hwc = &event->hw;
7217 if (!is_sampling_event(event))
7220 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7221 hwc->hrtimer.function = perf_swevent_hrtimer;
7224 * Since hrtimers have a fixed rate, we can do a static freq->period
7225 * mapping and avoid the whole period adjust feedback stuff.
7227 if (event->attr.freq) {
7228 long freq = event->attr.sample_freq;
7230 event->attr.sample_period = NSEC_PER_SEC / freq;
7231 hwc->sample_period = event->attr.sample_period;
7232 local64_set(&hwc->period_left, hwc->sample_period);
7233 hwc->last_period = hwc->sample_period;
7234 event->attr.freq = 0;
7239 * Software event: cpu wall time clock
7242 static void cpu_clock_event_update(struct perf_event *event)
7247 now = local_clock();
7248 prev = local64_xchg(&event->hw.prev_count, now);
7249 local64_add(now - prev, &event->count);
7252 static void cpu_clock_event_start(struct perf_event *event, int flags)
7254 local64_set(&event->hw.prev_count, local_clock());
7255 perf_swevent_start_hrtimer(event);
7258 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7260 perf_swevent_cancel_hrtimer(event);
7261 cpu_clock_event_update(event);
7264 static int cpu_clock_event_add(struct perf_event *event, int flags)
7266 if (flags & PERF_EF_START)
7267 cpu_clock_event_start(event, flags);
7268 perf_event_update_userpage(event);
7273 static void cpu_clock_event_del(struct perf_event *event, int flags)
7275 cpu_clock_event_stop(event, flags);
7278 static void cpu_clock_event_read(struct perf_event *event)
7280 cpu_clock_event_update(event);
7283 static int cpu_clock_event_init(struct perf_event *event)
7285 if (event->attr.type != PERF_TYPE_SOFTWARE)
7288 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7292 * no branch sampling for software events
7294 if (has_branch_stack(event))
7297 perf_swevent_init_hrtimer(event);
7302 static struct pmu perf_cpu_clock = {
7303 .task_ctx_nr = perf_sw_context,
7305 .capabilities = PERF_PMU_CAP_NO_NMI,
7307 .event_init = cpu_clock_event_init,
7308 .add = cpu_clock_event_add,
7309 .del = cpu_clock_event_del,
7310 .start = cpu_clock_event_start,
7311 .stop = cpu_clock_event_stop,
7312 .read = cpu_clock_event_read,
7316 * Software event: task time clock
7319 static void task_clock_event_update(struct perf_event *event, u64 now)
7324 prev = local64_xchg(&event->hw.prev_count, now);
7326 local64_add(delta, &event->count);
7329 static void task_clock_event_start(struct perf_event *event, int flags)
7331 local64_set(&event->hw.prev_count, event->ctx->time);
7332 perf_swevent_start_hrtimer(event);
7335 static void task_clock_event_stop(struct perf_event *event, int flags)
7337 perf_swevent_cancel_hrtimer(event);
7338 task_clock_event_update(event, event->ctx->time);
7341 static int task_clock_event_add(struct perf_event *event, int flags)
7343 if (flags & PERF_EF_START)
7344 task_clock_event_start(event, flags);
7345 perf_event_update_userpage(event);
7350 static void task_clock_event_del(struct perf_event *event, int flags)
7352 task_clock_event_stop(event, PERF_EF_UPDATE);
7355 static void task_clock_event_read(struct perf_event *event)
7357 u64 now = perf_clock();
7358 u64 delta = now - event->ctx->timestamp;
7359 u64 time = event->ctx->time + delta;
7361 task_clock_event_update(event, time);
7364 static int task_clock_event_init(struct perf_event *event)
7366 if (event->attr.type != PERF_TYPE_SOFTWARE)
7369 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7373 * no branch sampling for software events
7375 if (has_branch_stack(event))
7378 perf_swevent_init_hrtimer(event);
7383 static struct pmu perf_task_clock = {
7384 .task_ctx_nr = perf_sw_context,
7386 .capabilities = PERF_PMU_CAP_NO_NMI,
7388 .event_init = task_clock_event_init,
7389 .add = task_clock_event_add,
7390 .del = task_clock_event_del,
7391 .start = task_clock_event_start,
7392 .stop = task_clock_event_stop,
7393 .read = task_clock_event_read,
7396 static void perf_pmu_nop_void(struct pmu *pmu)
7400 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7404 static int perf_pmu_nop_int(struct pmu *pmu)
7409 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7411 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7413 __this_cpu_write(nop_txn_flags, flags);
7415 if (flags & ~PERF_PMU_TXN_ADD)
7418 perf_pmu_disable(pmu);
7421 static int perf_pmu_commit_txn(struct pmu *pmu)
7423 unsigned int flags = __this_cpu_read(nop_txn_flags);
7425 __this_cpu_write(nop_txn_flags, 0);
7427 if (flags & ~PERF_PMU_TXN_ADD)
7430 perf_pmu_enable(pmu);
7434 static void perf_pmu_cancel_txn(struct pmu *pmu)
7436 unsigned int flags = __this_cpu_read(nop_txn_flags);
7438 __this_cpu_write(nop_txn_flags, 0);
7440 if (flags & ~PERF_PMU_TXN_ADD)
7443 perf_pmu_enable(pmu);
7446 static int perf_event_idx_default(struct perf_event *event)
7452 * Ensures all contexts with the same task_ctx_nr have the same
7453 * pmu_cpu_context too.
7455 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7462 list_for_each_entry(pmu, &pmus, entry) {
7463 if (pmu->task_ctx_nr == ctxn)
7464 return pmu->pmu_cpu_context;
7470 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7474 for_each_possible_cpu(cpu) {
7475 struct perf_cpu_context *cpuctx;
7477 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7479 if (cpuctx->unique_pmu == old_pmu)
7480 cpuctx->unique_pmu = pmu;
7484 static void free_pmu_context(struct pmu *pmu)
7488 mutex_lock(&pmus_lock);
7490 * Like a real lame refcount.
7492 list_for_each_entry(i, &pmus, entry) {
7493 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7494 update_pmu_context(i, pmu);
7499 free_percpu(pmu->pmu_cpu_context);
7501 mutex_unlock(&pmus_lock);
7503 static struct idr pmu_idr;
7506 type_show(struct device *dev, struct device_attribute *attr, char *page)
7508 struct pmu *pmu = dev_get_drvdata(dev);
7510 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7512 static DEVICE_ATTR_RO(type);
7515 perf_event_mux_interval_ms_show(struct device *dev,
7516 struct device_attribute *attr,
7519 struct pmu *pmu = dev_get_drvdata(dev);
7521 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7524 static DEFINE_MUTEX(mux_interval_mutex);
7527 perf_event_mux_interval_ms_store(struct device *dev,
7528 struct device_attribute *attr,
7529 const char *buf, size_t count)
7531 struct pmu *pmu = dev_get_drvdata(dev);
7532 int timer, cpu, ret;
7534 ret = kstrtoint(buf, 0, &timer);
7541 /* same value, noting to do */
7542 if (timer == pmu->hrtimer_interval_ms)
7545 mutex_lock(&mux_interval_mutex);
7546 pmu->hrtimer_interval_ms = timer;
7548 /* update all cpuctx for this PMU */
7550 for_each_online_cpu(cpu) {
7551 struct perf_cpu_context *cpuctx;
7552 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7553 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7555 cpu_function_call(cpu,
7556 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7559 mutex_unlock(&mux_interval_mutex);
7563 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7565 static struct attribute *pmu_dev_attrs[] = {
7566 &dev_attr_type.attr,
7567 &dev_attr_perf_event_mux_interval_ms.attr,
7570 ATTRIBUTE_GROUPS(pmu_dev);
7572 static int pmu_bus_running;
7573 static struct bus_type pmu_bus = {
7574 .name = "event_source",
7575 .dev_groups = pmu_dev_groups,
7578 static void pmu_dev_release(struct device *dev)
7583 static int pmu_dev_alloc(struct pmu *pmu)
7587 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7591 pmu->dev->groups = pmu->attr_groups;
7592 device_initialize(pmu->dev);
7593 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7597 dev_set_drvdata(pmu->dev, pmu);
7598 pmu->dev->bus = &pmu_bus;
7599 pmu->dev->release = pmu_dev_release;
7600 ret = device_add(pmu->dev);
7608 put_device(pmu->dev);
7612 static struct lock_class_key cpuctx_mutex;
7613 static struct lock_class_key cpuctx_lock;
7615 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7619 mutex_lock(&pmus_lock);
7621 pmu->pmu_disable_count = alloc_percpu(int);
7622 if (!pmu->pmu_disable_count)
7631 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7639 if (pmu_bus_running) {
7640 ret = pmu_dev_alloc(pmu);
7646 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7647 if (pmu->pmu_cpu_context)
7648 goto got_cpu_context;
7651 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7652 if (!pmu->pmu_cpu_context)
7655 for_each_possible_cpu(cpu) {
7656 struct perf_cpu_context *cpuctx;
7658 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7659 __perf_event_init_context(&cpuctx->ctx);
7660 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7661 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7662 cpuctx->ctx.pmu = pmu;
7664 __perf_mux_hrtimer_init(cpuctx, cpu);
7666 cpuctx->unique_pmu = pmu;
7670 if (!pmu->start_txn) {
7671 if (pmu->pmu_enable) {
7673 * If we have pmu_enable/pmu_disable calls, install
7674 * transaction stubs that use that to try and batch
7675 * hardware accesses.
7677 pmu->start_txn = perf_pmu_start_txn;
7678 pmu->commit_txn = perf_pmu_commit_txn;
7679 pmu->cancel_txn = perf_pmu_cancel_txn;
7681 pmu->start_txn = perf_pmu_nop_txn;
7682 pmu->commit_txn = perf_pmu_nop_int;
7683 pmu->cancel_txn = perf_pmu_nop_void;
7687 if (!pmu->pmu_enable) {
7688 pmu->pmu_enable = perf_pmu_nop_void;
7689 pmu->pmu_disable = perf_pmu_nop_void;
7692 if (!pmu->event_idx)
7693 pmu->event_idx = perf_event_idx_default;
7695 list_add_rcu(&pmu->entry, &pmus);
7696 atomic_set(&pmu->exclusive_cnt, 0);
7699 mutex_unlock(&pmus_lock);
7704 device_del(pmu->dev);
7705 put_device(pmu->dev);
7708 if (pmu->type >= PERF_TYPE_MAX)
7709 idr_remove(&pmu_idr, pmu->type);
7712 free_percpu(pmu->pmu_disable_count);
7715 EXPORT_SYMBOL_GPL(perf_pmu_register);
7717 void perf_pmu_unregister(struct pmu *pmu)
7719 mutex_lock(&pmus_lock);
7720 list_del_rcu(&pmu->entry);
7721 mutex_unlock(&pmus_lock);
7724 * We dereference the pmu list under both SRCU and regular RCU, so
7725 * synchronize against both of those.
7727 synchronize_srcu(&pmus_srcu);
7730 free_percpu(pmu->pmu_disable_count);
7731 if (pmu->type >= PERF_TYPE_MAX)
7732 idr_remove(&pmu_idr, pmu->type);
7733 device_del(pmu->dev);
7734 put_device(pmu->dev);
7735 free_pmu_context(pmu);
7737 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7739 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7741 struct perf_event_context *ctx = NULL;
7744 if (!try_module_get(pmu->module))
7747 if (event->group_leader != event) {
7749 * This ctx->mutex can nest when we're called through
7750 * inheritance. See the perf_event_ctx_lock_nested() comment.
7752 ctx = perf_event_ctx_lock_nested(event->group_leader,
7753 SINGLE_DEPTH_NESTING);
7758 ret = pmu->event_init(event);
7761 perf_event_ctx_unlock(event->group_leader, ctx);
7764 module_put(pmu->module);
7769 static struct pmu *perf_init_event(struct perf_event *event)
7771 struct pmu *pmu = NULL;
7775 idx = srcu_read_lock(&pmus_srcu);
7778 pmu = idr_find(&pmu_idr, event->attr.type);
7781 ret = perf_try_init_event(pmu, event);
7787 list_for_each_entry_rcu(pmu, &pmus, entry) {
7788 ret = perf_try_init_event(pmu, event);
7792 if (ret != -ENOENT) {
7797 pmu = ERR_PTR(-ENOENT);
7799 srcu_read_unlock(&pmus_srcu, idx);
7804 static void account_event_cpu(struct perf_event *event, int cpu)
7809 if (is_cgroup_event(event))
7810 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7813 static void account_event(struct perf_event *event)
7818 if (event->attach_state & PERF_ATTACH_TASK)
7819 static_key_slow_inc(&perf_sched_events.key);
7820 if (event->attr.mmap || event->attr.mmap_data)
7821 atomic_inc(&nr_mmap_events);
7822 if (event->attr.comm)
7823 atomic_inc(&nr_comm_events);
7824 if (event->attr.task)
7825 atomic_inc(&nr_task_events);
7826 if (event->attr.freq) {
7827 if (atomic_inc_return(&nr_freq_events) == 1)
7828 tick_nohz_full_kick_all();
7830 if (event->attr.context_switch) {
7831 atomic_inc(&nr_switch_events);
7832 static_key_slow_inc(&perf_sched_events.key);
7834 if (has_branch_stack(event))
7835 static_key_slow_inc(&perf_sched_events.key);
7836 if (is_cgroup_event(event))
7837 static_key_slow_inc(&perf_sched_events.key);
7839 account_event_cpu(event, event->cpu);
7843 * Allocate and initialize a event structure
7845 static struct perf_event *
7846 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7847 struct task_struct *task,
7848 struct perf_event *group_leader,
7849 struct perf_event *parent_event,
7850 perf_overflow_handler_t overflow_handler,
7851 void *context, int cgroup_fd)
7854 struct perf_event *event;
7855 struct hw_perf_event *hwc;
7858 if ((unsigned)cpu >= nr_cpu_ids) {
7859 if (!task || cpu != -1)
7860 return ERR_PTR(-EINVAL);
7863 event = kzalloc(sizeof(*event), GFP_KERNEL);
7865 return ERR_PTR(-ENOMEM);
7868 * Single events are their own group leaders, with an
7869 * empty sibling list:
7872 group_leader = event;
7874 mutex_init(&event->child_mutex);
7875 INIT_LIST_HEAD(&event->child_list);
7877 INIT_LIST_HEAD(&event->group_entry);
7878 INIT_LIST_HEAD(&event->event_entry);
7879 INIT_LIST_HEAD(&event->sibling_list);
7880 INIT_LIST_HEAD(&event->rb_entry);
7881 INIT_LIST_HEAD(&event->active_entry);
7882 INIT_HLIST_NODE(&event->hlist_entry);
7885 init_waitqueue_head(&event->waitq);
7886 init_irq_work(&event->pending, perf_pending_event);
7888 mutex_init(&event->mmap_mutex);
7890 atomic_long_set(&event->refcount, 1);
7892 event->attr = *attr;
7893 event->group_leader = group_leader;
7897 event->parent = parent_event;
7899 event->ns = get_pid_ns(task_active_pid_ns(current));
7900 event->id = atomic64_inc_return(&perf_event_id);
7902 event->state = PERF_EVENT_STATE_INACTIVE;
7905 event->attach_state = PERF_ATTACH_TASK;
7907 * XXX pmu::event_init needs to know what task to account to
7908 * and we cannot use the ctx information because we need the
7909 * pmu before we get a ctx.
7911 event->hw.target = task;
7914 event->clock = &local_clock;
7916 event->clock = parent_event->clock;
7918 if (!overflow_handler && parent_event) {
7919 overflow_handler = parent_event->overflow_handler;
7920 context = parent_event->overflow_handler_context;
7923 event->overflow_handler = overflow_handler;
7924 event->overflow_handler_context = context;
7926 perf_event__state_init(event);
7931 hwc->sample_period = attr->sample_period;
7932 if (attr->freq && attr->sample_freq)
7933 hwc->sample_period = 1;
7934 hwc->last_period = hwc->sample_period;
7936 local64_set(&hwc->period_left, hwc->sample_period);
7939 * we currently do not support PERF_FORMAT_GROUP on inherited events
7941 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
7944 if (!has_branch_stack(event))
7945 event->attr.branch_sample_type = 0;
7947 if (cgroup_fd != -1) {
7948 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
7953 pmu = perf_init_event(event);
7956 else if (IS_ERR(pmu)) {
7961 err = exclusive_event_init(event);
7965 if (!event->parent) {
7966 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
7967 err = get_callchain_buffers();
7973 /* symmetric to unaccount_event() in _free_event() */
7974 account_event(event);
7979 exclusive_event_destroy(event);
7983 event->destroy(event);
7984 module_put(pmu->module);
7986 if (is_cgroup_event(event))
7987 perf_detach_cgroup(event);
7989 put_pid_ns(event->ns);
7992 return ERR_PTR(err);
7995 static int perf_copy_attr(struct perf_event_attr __user *uattr,
7996 struct perf_event_attr *attr)
8001 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8005 * zero the full structure, so that a short copy will be nice.
8007 memset(attr, 0, sizeof(*attr));
8009 ret = get_user(size, &uattr->size);
8013 if (size > PAGE_SIZE) /* silly large */
8016 if (!size) /* abi compat */
8017 size = PERF_ATTR_SIZE_VER0;
8019 if (size < PERF_ATTR_SIZE_VER0)
8023 * If we're handed a bigger struct than we know of,
8024 * ensure all the unknown bits are 0 - i.e. new
8025 * user-space does not rely on any kernel feature
8026 * extensions we dont know about yet.
8028 if (size > sizeof(*attr)) {
8029 unsigned char __user *addr;
8030 unsigned char __user *end;
8033 addr = (void __user *)uattr + sizeof(*attr);
8034 end = (void __user *)uattr + size;
8036 for (; addr < end; addr++) {
8037 ret = get_user(val, addr);
8043 size = sizeof(*attr);
8046 ret = copy_from_user(attr, uattr, size);
8050 if (attr->__reserved_1)
8053 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8056 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8059 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8060 u64 mask = attr->branch_sample_type;
8062 /* only using defined bits */
8063 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8066 /* at least one branch bit must be set */
8067 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8070 /* propagate priv level, when not set for branch */
8071 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8073 /* exclude_kernel checked on syscall entry */
8074 if (!attr->exclude_kernel)
8075 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8077 if (!attr->exclude_user)
8078 mask |= PERF_SAMPLE_BRANCH_USER;
8080 if (!attr->exclude_hv)
8081 mask |= PERF_SAMPLE_BRANCH_HV;
8083 * adjust user setting (for HW filter setup)
8085 attr->branch_sample_type = mask;
8087 /* privileged levels capture (kernel, hv): check permissions */
8088 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8089 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8093 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8094 ret = perf_reg_validate(attr->sample_regs_user);
8099 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8100 if (!arch_perf_have_user_stack_dump())
8104 * We have __u32 type for the size, but so far
8105 * we can only use __u16 as maximum due to the
8106 * __u16 sample size limit.
8108 if (attr->sample_stack_user >= USHRT_MAX)
8110 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8114 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8115 ret = perf_reg_validate(attr->sample_regs_intr);
8120 put_user(sizeof(*attr), &uattr->size);
8126 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8128 struct ring_buffer *rb = NULL;
8134 /* don't allow circular references */
8135 if (event == output_event)
8139 * Don't allow cross-cpu buffers
8141 if (output_event->cpu != event->cpu)
8145 * If its not a per-cpu rb, it must be the same task.
8147 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8151 * Mixing clocks in the same buffer is trouble you don't need.
8153 if (output_event->clock != event->clock)
8157 * If both events generate aux data, they must be on the same PMU
8159 if (has_aux(event) && has_aux(output_event) &&
8160 event->pmu != output_event->pmu)
8164 mutex_lock(&event->mmap_mutex);
8165 /* Can't redirect output if we've got an active mmap() */
8166 if (atomic_read(&event->mmap_count))
8170 /* get the rb we want to redirect to */
8171 rb = ring_buffer_get(output_event);
8176 ring_buffer_attach(event, rb);
8180 mutex_unlock(&event->mmap_mutex);
8186 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8192 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8195 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8197 bool nmi_safe = false;
8200 case CLOCK_MONOTONIC:
8201 event->clock = &ktime_get_mono_fast_ns;
8205 case CLOCK_MONOTONIC_RAW:
8206 event->clock = &ktime_get_raw_fast_ns;
8210 case CLOCK_REALTIME:
8211 event->clock = &ktime_get_real_ns;
8214 case CLOCK_BOOTTIME:
8215 event->clock = &ktime_get_boot_ns;
8219 event->clock = &ktime_get_tai_ns;
8226 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8233 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8235 * @attr_uptr: event_id type attributes for monitoring/sampling
8238 * @group_fd: group leader event fd
8240 SYSCALL_DEFINE5(perf_event_open,
8241 struct perf_event_attr __user *, attr_uptr,
8242 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8244 struct perf_event *group_leader = NULL, *output_event = NULL;
8245 struct perf_event *event, *sibling;
8246 struct perf_event_attr attr;
8247 struct perf_event_context *ctx, *uninitialized_var(gctx);
8248 struct file *event_file = NULL;
8249 struct fd group = {NULL, 0};
8250 struct task_struct *task = NULL;
8255 int f_flags = O_RDWR;
8258 /* for future expandability... */
8259 if (flags & ~PERF_FLAG_ALL)
8262 err = perf_copy_attr(attr_uptr, &attr);
8266 if (!attr.exclude_kernel) {
8267 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8272 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8275 if (attr.sample_period & (1ULL << 63))
8280 * In cgroup mode, the pid argument is used to pass the fd
8281 * opened to the cgroup directory in cgroupfs. The cpu argument
8282 * designates the cpu on which to monitor threads from that
8285 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8288 if (flags & PERF_FLAG_FD_CLOEXEC)
8289 f_flags |= O_CLOEXEC;
8291 event_fd = get_unused_fd_flags(f_flags);
8295 if (group_fd != -1) {
8296 err = perf_fget_light(group_fd, &group);
8299 group_leader = group.file->private_data;
8300 if (flags & PERF_FLAG_FD_OUTPUT)
8301 output_event = group_leader;
8302 if (flags & PERF_FLAG_FD_NO_GROUP)
8303 group_leader = NULL;
8306 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8307 task = find_lively_task_by_vpid(pid);
8309 err = PTR_ERR(task);
8314 if (task && group_leader &&
8315 group_leader->attr.inherit != attr.inherit) {
8323 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
8328 * Reuse ptrace permission checks for now.
8330 * We must hold cred_guard_mutex across this and any potential
8331 * perf_install_in_context() call for this new event to
8332 * serialize against exec() altering our credentials (and the
8333 * perf_event_exit_task() that could imply).
8336 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
8340 if (flags & PERF_FLAG_PID_CGROUP)
8343 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8344 NULL, NULL, cgroup_fd);
8345 if (IS_ERR(event)) {
8346 err = PTR_ERR(event);
8350 if (is_sampling_event(event)) {
8351 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8358 * Special case software events and allow them to be part of
8359 * any hardware group.
8363 if (attr.use_clockid) {
8364 err = perf_event_set_clock(event, attr.clockid);
8370 (is_software_event(event) != is_software_event(group_leader))) {
8371 if (is_software_event(event)) {
8373 * If event and group_leader are not both a software
8374 * event, and event is, then group leader is not.
8376 * Allow the addition of software events to !software
8377 * groups, this is safe because software events never
8380 pmu = group_leader->pmu;
8381 } else if (is_software_event(group_leader) &&
8382 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8384 * In case the group is a pure software group, and we
8385 * try to add a hardware event, move the whole group to
8386 * the hardware context.
8393 * Get the target context (task or percpu):
8395 ctx = find_get_context(pmu, task, event);
8401 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8407 * Look up the group leader (we will attach this event to it):
8413 * Do not allow a recursive hierarchy (this new sibling
8414 * becoming part of another group-sibling):
8416 if (group_leader->group_leader != group_leader)
8419 /* All events in a group should have the same clock */
8420 if (group_leader->clock != event->clock)
8424 * Do not allow to attach to a group in a different
8425 * task or CPU context:
8429 * Make sure we're both on the same task, or both
8432 if (group_leader->ctx->task != ctx->task)
8436 * Make sure we're both events for the same CPU;
8437 * grouping events for different CPUs is broken; since
8438 * you can never concurrently schedule them anyhow.
8440 if (group_leader->cpu != event->cpu)
8443 if (group_leader->ctx != ctx)
8448 * Only a group leader can be exclusive or pinned
8450 if (attr.exclusive || attr.pinned)
8455 err = perf_event_set_output(event, output_event);
8460 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8462 if (IS_ERR(event_file)) {
8463 err = PTR_ERR(event_file);
8468 gctx = group_leader->ctx;
8469 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8471 mutex_lock(&ctx->mutex);
8474 if (!perf_event_validate_size(event)) {
8480 * Must be under the same ctx::mutex as perf_install_in_context(),
8481 * because we need to serialize with concurrent event creation.
8483 if (!exclusive_event_installable(event, ctx)) {
8484 /* exclusive and group stuff are assumed mutually exclusive */
8485 WARN_ON_ONCE(move_group);
8491 WARN_ON_ONCE(ctx->parent_ctx);
8494 * This is the point on no return; we cannot fail hereafter. This is
8495 * where we start modifying current state.
8500 * See perf_event_ctx_lock() for comments on the details
8501 * of swizzling perf_event::ctx.
8503 perf_remove_from_context(group_leader, false);
8505 list_for_each_entry(sibling, &group_leader->sibling_list,
8507 perf_remove_from_context(sibling, false);
8512 * Wait for everybody to stop referencing the events through
8513 * the old lists, before installing it on new lists.
8518 * Install the group siblings before the group leader.
8520 * Because a group leader will try and install the entire group
8521 * (through the sibling list, which is still in-tact), we can
8522 * end up with siblings installed in the wrong context.
8524 * By installing siblings first we NO-OP because they're not
8525 * reachable through the group lists.
8527 list_for_each_entry(sibling, &group_leader->sibling_list,
8529 perf_event__state_init(sibling);
8530 perf_install_in_context(ctx, sibling, sibling->cpu);
8535 * Removing from the context ends up with disabled
8536 * event. What we want here is event in the initial
8537 * startup state, ready to be add into new context.
8539 perf_event__state_init(group_leader);
8540 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8544 * Now that all events are installed in @ctx, nothing
8545 * references @gctx anymore, so drop the last reference we have
8552 * Precalculate sample_data sizes; do while holding ctx::mutex such
8553 * that we're serialized against further additions and before
8554 * perf_install_in_context() which is the point the event is active and
8555 * can use these values.
8557 perf_event__header_size(event);
8558 perf_event__id_header_size(event);
8560 perf_install_in_context(ctx, event, event->cpu);
8561 perf_unpin_context(ctx);
8564 mutex_unlock(&gctx->mutex);
8565 mutex_unlock(&ctx->mutex);
8568 mutex_unlock(&task->signal->cred_guard_mutex);
8569 put_task_struct(task);
8574 event->owner = current;
8576 mutex_lock(¤t->perf_event_mutex);
8577 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8578 mutex_unlock(¤t->perf_event_mutex);
8581 * Drop the reference on the group_event after placing the
8582 * new event on the sibling_list. This ensures destruction
8583 * of the group leader will find the pointer to itself in
8584 * perf_group_detach().
8587 fd_install(event_fd, event_file);
8592 mutex_unlock(&gctx->mutex);
8593 mutex_unlock(&ctx->mutex);
8597 perf_unpin_context(ctx);
8601 * If event_file is set, the fput() above will have called ->release()
8602 * and that will take care of freeing the event.
8608 mutex_unlock(&task->signal->cred_guard_mutex);
8613 put_task_struct(task);
8617 put_unused_fd(event_fd);
8622 * perf_event_create_kernel_counter
8624 * @attr: attributes of the counter to create
8625 * @cpu: cpu in which the counter is bound
8626 * @task: task to profile (NULL for percpu)
8629 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8630 struct task_struct *task,
8631 perf_overflow_handler_t overflow_handler,
8634 struct perf_event_context *ctx;
8635 struct perf_event *event;
8639 * Get the target context (task or percpu):
8642 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8643 overflow_handler, context, -1);
8644 if (IS_ERR(event)) {
8645 err = PTR_ERR(event);
8649 /* Mark owner so we could distinguish it from user events. */
8650 event->owner = EVENT_OWNER_KERNEL;
8652 ctx = find_get_context(event->pmu, task, event);
8658 WARN_ON_ONCE(ctx->parent_ctx);
8659 mutex_lock(&ctx->mutex);
8660 if (!exclusive_event_installable(event, ctx)) {
8661 mutex_unlock(&ctx->mutex);
8662 perf_unpin_context(ctx);
8668 perf_install_in_context(ctx, event, cpu);
8669 perf_unpin_context(ctx);
8670 mutex_unlock(&ctx->mutex);
8677 return ERR_PTR(err);
8679 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8681 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8683 struct perf_event_context *src_ctx;
8684 struct perf_event_context *dst_ctx;
8685 struct perf_event *event, *tmp;
8688 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8689 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8692 * See perf_event_ctx_lock() for comments on the details
8693 * of swizzling perf_event::ctx.
8695 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8696 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8698 perf_remove_from_context(event, false);
8699 unaccount_event_cpu(event, src_cpu);
8701 list_add(&event->migrate_entry, &events);
8705 * Wait for the events to quiesce before re-instating them.
8710 * Re-instate events in 2 passes.
8712 * Skip over group leaders and only install siblings on this first
8713 * pass, siblings will not get enabled without a leader, however a
8714 * leader will enable its siblings, even if those are still on the old
8717 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8718 if (event->group_leader == event)
8721 list_del(&event->migrate_entry);
8722 if (event->state >= PERF_EVENT_STATE_OFF)
8723 event->state = PERF_EVENT_STATE_INACTIVE;
8724 account_event_cpu(event, dst_cpu);
8725 perf_install_in_context(dst_ctx, event, dst_cpu);
8730 * Once all the siblings are setup properly, install the group leaders
8733 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8734 list_del(&event->migrate_entry);
8735 if (event->state >= PERF_EVENT_STATE_OFF)
8736 event->state = PERF_EVENT_STATE_INACTIVE;
8737 account_event_cpu(event, dst_cpu);
8738 perf_install_in_context(dst_ctx, event, dst_cpu);
8741 mutex_unlock(&dst_ctx->mutex);
8742 mutex_unlock(&src_ctx->mutex);
8744 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8746 static void sync_child_event(struct perf_event *child_event,
8747 struct task_struct *child)
8749 struct perf_event *parent_event = child_event->parent;
8752 if (child_event->attr.inherit_stat)
8753 perf_event_read_event(child_event, child);
8755 child_val = perf_event_count(child_event);
8758 * Add back the child's count to the parent's count:
8760 atomic64_add(child_val, &parent_event->child_count);
8761 atomic64_add(child_event->total_time_enabled,
8762 &parent_event->child_total_time_enabled);
8763 atomic64_add(child_event->total_time_running,
8764 &parent_event->child_total_time_running);
8767 * Remove this event from the parent's list
8769 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8770 mutex_lock(&parent_event->child_mutex);
8771 list_del_init(&child_event->child_list);
8772 mutex_unlock(&parent_event->child_mutex);
8775 * Make sure user/parent get notified, that we just
8778 perf_event_wakeup(parent_event);
8781 * Release the parent event, if this was the last
8784 put_event(parent_event);
8788 __perf_event_exit_task(struct perf_event *child_event,
8789 struct perf_event_context *child_ctx,
8790 struct task_struct *child)
8793 * Do not destroy the 'original' grouping; because of the context
8794 * switch optimization the original events could've ended up in a
8795 * random child task.
8797 * If we were to destroy the original group, all group related
8798 * operations would cease to function properly after this random
8801 * Do destroy all inherited groups, we don't care about those
8802 * and being thorough is better.
8804 perf_remove_from_context(child_event, !!child_event->parent);
8807 * It can happen that the parent exits first, and has events
8808 * that are still around due to the child reference. These
8809 * events need to be zapped.
8811 if (child_event->parent) {
8812 sync_child_event(child_event, child);
8813 free_event(child_event);
8815 child_event->state = PERF_EVENT_STATE_EXIT;
8816 perf_event_wakeup(child_event);
8820 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8822 struct perf_event *child_event, *next;
8823 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8824 unsigned long flags;
8826 if (likely(!child->perf_event_ctxp[ctxn]))
8829 local_irq_save(flags);
8831 * We can't reschedule here because interrupts are disabled,
8832 * and either child is current or it is a task that can't be
8833 * scheduled, so we are now safe from rescheduling changing
8836 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8839 * Take the context lock here so that if find_get_context is
8840 * reading child->perf_event_ctxp, we wait until it has
8841 * incremented the context's refcount before we do put_ctx below.
8843 raw_spin_lock(&child_ctx->lock);
8844 task_ctx_sched_out(child_ctx);
8845 child->perf_event_ctxp[ctxn] = NULL;
8848 * If this context is a clone; unclone it so it can't get
8849 * swapped to another process while we're removing all
8850 * the events from it.
8852 clone_ctx = unclone_ctx(child_ctx);
8853 update_context_time(child_ctx);
8854 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8860 * Report the task dead after unscheduling the events so that we
8861 * won't get any samples after PERF_RECORD_EXIT. We can however still
8862 * get a few PERF_RECORD_READ events.
8864 perf_event_task(child, child_ctx, 0);
8867 * We can recurse on the same lock type through:
8869 * __perf_event_exit_task()
8870 * sync_child_event()
8872 * mutex_lock(&ctx->mutex)
8874 * But since its the parent context it won't be the same instance.
8876 mutex_lock(&child_ctx->mutex);
8878 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8879 __perf_event_exit_task(child_event, child_ctx, child);
8881 mutex_unlock(&child_ctx->mutex);
8887 * When a child task exits, feed back event values to parent events.
8889 * Can be called with cred_guard_mutex held when called from
8890 * install_exec_creds().
8892 void perf_event_exit_task(struct task_struct *child)
8894 struct perf_event *event, *tmp;
8897 mutex_lock(&child->perf_event_mutex);
8898 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
8900 list_del_init(&event->owner_entry);
8903 * Ensure the list deletion is visible before we clear
8904 * the owner, closes a race against perf_release() where
8905 * we need to serialize on the owner->perf_event_mutex.
8908 event->owner = NULL;
8910 mutex_unlock(&child->perf_event_mutex);
8912 for_each_task_context_nr(ctxn)
8913 perf_event_exit_task_context(child, ctxn);
8916 * The perf_event_exit_task_context calls perf_event_task
8917 * with child's task_ctx, which generates EXIT events for
8918 * child contexts and sets child->perf_event_ctxp[] to NULL.
8919 * At this point we need to send EXIT events to cpu contexts.
8921 perf_event_task(child, NULL, 0);
8924 static void perf_free_event(struct perf_event *event,
8925 struct perf_event_context *ctx)
8927 struct perf_event *parent = event->parent;
8929 if (WARN_ON_ONCE(!parent))
8932 mutex_lock(&parent->child_mutex);
8933 list_del_init(&event->child_list);
8934 mutex_unlock(&parent->child_mutex);
8938 raw_spin_lock_irq(&ctx->lock);
8939 perf_group_detach(event);
8940 list_del_event(event, ctx);
8941 raw_spin_unlock_irq(&ctx->lock);
8946 * Free an unexposed, unused context as created by inheritance by
8947 * perf_event_init_task below, used by fork() in case of fail.
8949 * Not all locks are strictly required, but take them anyway to be nice and
8950 * help out with the lockdep assertions.
8952 void perf_event_free_task(struct task_struct *task)
8954 struct perf_event_context *ctx;
8955 struct perf_event *event, *tmp;
8958 for_each_task_context_nr(ctxn) {
8959 ctx = task->perf_event_ctxp[ctxn];
8963 mutex_lock(&ctx->mutex);
8965 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
8967 perf_free_event(event, ctx);
8969 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
8971 perf_free_event(event, ctx);
8973 if (!list_empty(&ctx->pinned_groups) ||
8974 !list_empty(&ctx->flexible_groups))
8977 mutex_unlock(&ctx->mutex);
8983 void perf_event_delayed_put(struct task_struct *task)
8987 for_each_task_context_nr(ctxn)
8988 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
8991 struct perf_event *perf_event_get(unsigned int fd)
8995 struct perf_event *event;
8997 err = perf_fget_light(fd, &f);
8999 return ERR_PTR(err);
9001 event = f.file->private_data;
9002 atomic_long_inc(&event->refcount);
9008 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9011 return ERR_PTR(-EINVAL);
9013 return &event->attr;
9017 * inherit a event from parent task to child task:
9019 static struct perf_event *
9020 inherit_event(struct perf_event *parent_event,
9021 struct task_struct *parent,
9022 struct perf_event_context *parent_ctx,
9023 struct task_struct *child,
9024 struct perf_event *group_leader,
9025 struct perf_event_context *child_ctx)
9027 enum perf_event_active_state parent_state = parent_event->state;
9028 struct perf_event *child_event;
9029 unsigned long flags;
9032 * Instead of creating recursive hierarchies of events,
9033 * we link inherited events back to the original parent,
9034 * which has a filp for sure, which we use as the reference
9037 if (parent_event->parent)
9038 parent_event = parent_event->parent;
9040 child_event = perf_event_alloc(&parent_event->attr,
9043 group_leader, parent_event,
9045 if (IS_ERR(child_event))
9048 if (is_orphaned_event(parent_event) ||
9049 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9050 free_event(child_event);
9057 * Make the child state follow the state of the parent event,
9058 * not its attr.disabled bit. We hold the parent's mutex,
9059 * so we won't race with perf_event_{en, dis}able_family.
9061 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9062 child_event->state = PERF_EVENT_STATE_INACTIVE;
9064 child_event->state = PERF_EVENT_STATE_OFF;
9066 if (parent_event->attr.freq) {
9067 u64 sample_period = parent_event->hw.sample_period;
9068 struct hw_perf_event *hwc = &child_event->hw;
9070 hwc->sample_period = sample_period;
9071 hwc->last_period = sample_period;
9073 local64_set(&hwc->period_left, sample_period);
9076 child_event->ctx = child_ctx;
9077 child_event->overflow_handler = parent_event->overflow_handler;
9078 child_event->overflow_handler_context
9079 = parent_event->overflow_handler_context;
9082 * Precalculate sample_data sizes
9084 perf_event__header_size(child_event);
9085 perf_event__id_header_size(child_event);
9088 * Link it up in the child's context:
9090 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9091 add_event_to_ctx(child_event, child_ctx);
9092 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9095 * Link this into the parent event's child list
9097 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9098 mutex_lock(&parent_event->child_mutex);
9099 list_add_tail(&child_event->child_list, &parent_event->child_list);
9100 mutex_unlock(&parent_event->child_mutex);
9105 static int inherit_group(struct perf_event *parent_event,
9106 struct task_struct *parent,
9107 struct perf_event_context *parent_ctx,
9108 struct task_struct *child,
9109 struct perf_event_context *child_ctx)
9111 struct perf_event *leader;
9112 struct perf_event *sub;
9113 struct perf_event *child_ctr;
9115 leader = inherit_event(parent_event, parent, parent_ctx,
9116 child, NULL, child_ctx);
9118 return PTR_ERR(leader);
9119 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9120 child_ctr = inherit_event(sub, parent, parent_ctx,
9121 child, leader, child_ctx);
9122 if (IS_ERR(child_ctr))
9123 return PTR_ERR(child_ctr);
9129 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9130 struct perf_event_context *parent_ctx,
9131 struct task_struct *child, int ctxn,
9135 struct perf_event_context *child_ctx;
9137 if (!event->attr.inherit) {
9142 child_ctx = child->perf_event_ctxp[ctxn];
9145 * This is executed from the parent task context, so
9146 * inherit events that have been marked for cloning.
9147 * First allocate and initialize a context for the
9151 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9155 child->perf_event_ctxp[ctxn] = child_ctx;
9158 ret = inherit_group(event, parent, parent_ctx,
9168 * Initialize the perf_event context in task_struct
9170 static int perf_event_init_context(struct task_struct *child, int ctxn)
9172 struct perf_event_context *child_ctx, *parent_ctx;
9173 struct perf_event_context *cloned_ctx;
9174 struct perf_event *event;
9175 struct task_struct *parent = current;
9176 int inherited_all = 1;
9177 unsigned long flags;
9180 if (likely(!parent->perf_event_ctxp[ctxn]))
9184 * If the parent's context is a clone, pin it so it won't get
9187 parent_ctx = perf_pin_task_context(parent, ctxn);
9192 * No need to check if parent_ctx != NULL here; since we saw
9193 * it non-NULL earlier, the only reason for it to become NULL
9194 * is if we exit, and since we're currently in the middle of
9195 * a fork we can't be exiting at the same time.
9199 * Lock the parent list. No need to lock the child - not PID
9200 * hashed yet and not running, so nobody can access it.
9202 mutex_lock(&parent_ctx->mutex);
9205 * We dont have to disable NMIs - we are only looking at
9206 * the list, not manipulating it:
9208 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9209 ret = inherit_task_group(event, parent, parent_ctx,
9210 child, ctxn, &inherited_all);
9216 * We can't hold ctx->lock when iterating the ->flexible_group list due
9217 * to allocations, but we need to prevent rotation because
9218 * rotate_ctx() will change the list from interrupt context.
9220 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9221 parent_ctx->rotate_disable = 1;
9222 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9224 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9225 ret = inherit_task_group(event, parent, parent_ctx,
9226 child, ctxn, &inherited_all);
9231 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9232 parent_ctx->rotate_disable = 0;
9234 child_ctx = child->perf_event_ctxp[ctxn];
9236 if (child_ctx && inherited_all) {
9238 * Mark the child context as a clone of the parent
9239 * context, or of whatever the parent is a clone of.
9241 * Note that if the parent is a clone, the holding of
9242 * parent_ctx->lock avoids it from being uncloned.
9244 cloned_ctx = parent_ctx->parent_ctx;
9246 child_ctx->parent_ctx = cloned_ctx;
9247 child_ctx->parent_gen = parent_ctx->parent_gen;
9249 child_ctx->parent_ctx = parent_ctx;
9250 child_ctx->parent_gen = parent_ctx->generation;
9252 get_ctx(child_ctx->parent_ctx);
9255 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9256 mutex_unlock(&parent_ctx->mutex);
9258 perf_unpin_context(parent_ctx);
9259 put_ctx(parent_ctx);
9265 * Initialize the perf_event context in task_struct
9267 int perf_event_init_task(struct task_struct *child)
9271 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9272 mutex_init(&child->perf_event_mutex);
9273 INIT_LIST_HEAD(&child->perf_event_list);
9275 for_each_task_context_nr(ctxn) {
9276 ret = perf_event_init_context(child, ctxn);
9278 perf_event_free_task(child);
9286 static void __init perf_event_init_all_cpus(void)
9288 struct swevent_htable *swhash;
9291 for_each_possible_cpu(cpu) {
9292 swhash = &per_cpu(swevent_htable, cpu);
9293 mutex_init(&swhash->hlist_mutex);
9294 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9298 static void perf_event_init_cpu(int cpu)
9300 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9302 mutex_lock(&swhash->hlist_mutex);
9303 if (swhash->hlist_refcount > 0) {
9304 struct swevent_hlist *hlist;
9306 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9308 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9310 mutex_unlock(&swhash->hlist_mutex);
9313 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9314 static void __perf_event_exit_context(void *__info)
9316 struct remove_event re = { .detach_group = true };
9317 struct perf_event_context *ctx = __info;
9320 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9321 __perf_remove_from_context(&re);
9325 static void perf_event_exit_cpu_context(int cpu)
9327 struct perf_event_context *ctx;
9331 idx = srcu_read_lock(&pmus_srcu);
9332 list_for_each_entry_rcu(pmu, &pmus, entry) {
9333 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9335 mutex_lock(&ctx->mutex);
9336 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9337 mutex_unlock(&ctx->mutex);
9339 srcu_read_unlock(&pmus_srcu, idx);
9342 static void perf_event_exit_cpu(int cpu)
9344 perf_event_exit_cpu_context(cpu);
9347 static inline void perf_event_exit_cpu(int cpu) { }
9351 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9355 for_each_online_cpu(cpu)
9356 perf_event_exit_cpu(cpu);
9362 * Run the perf reboot notifier at the very last possible moment so that
9363 * the generic watchdog code runs as long as possible.
9365 static struct notifier_block perf_reboot_notifier = {
9366 .notifier_call = perf_reboot,
9367 .priority = INT_MIN,
9371 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9373 unsigned int cpu = (long)hcpu;
9375 switch (action & ~CPU_TASKS_FROZEN) {
9377 case CPU_UP_PREPARE:
9378 case CPU_DOWN_FAILED:
9379 perf_event_init_cpu(cpu);
9382 case CPU_UP_CANCELED:
9383 case CPU_DOWN_PREPARE:
9384 perf_event_exit_cpu(cpu);
9393 void __init perf_event_init(void)
9399 perf_event_init_all_cpus();
9400 init_srcu_struct(&pmus_srcu);
9401 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9402 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9403 perf_pmu_register(&perf_task_clock, NULL, -1);
9405 perf_cpu_notifier(perf_cpu_notify);
9406 register_reboot_notifier(&perf_reboot_notifier);
9408 ret = init_hw_breakpoint();
9409 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9411 /* do not patch jump label more than once per second */
9412 jump_label_rate_limit(&perf_sched_events, HZ);
9415 * Build time assertion that we keep the data_head at the intended
9416 * location. IOW, validation we got the __reserved[] size right.
9418 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9422 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9425 struct perf_pmu_events_attr *pmu_attr =
9426 container_of(attr, struct perf_pmu_events_attr, attr);
9428 if (pmu_attr->event_str)
9429 return sprintf(page, "%s\n", pmu_attr->event_str);
9434 static int __init perf_event_sysfs_init(void)
9439 mutex_lock(&pmus_lock);
9441 ret = bus_register(&pmu_bus);
9445 list_for_each_entry(pmu, &pmus, entry) {
9446 if (!pmu->name || pmu->type < 0)
9449 ret = pmu_dev_alloc(pmu);
9450 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9452 pmu_bus_running = 1;
9456 mutex_unlock(&pmus_lock);
9460 device_initcall(perf_event_sysfs_init);
9462 #ifdef CONFIG_CGROUP_PERF
9463 static struct cgroup_subsys_state *
9464 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9466 struct perf_cgroup *jc;
9468 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9470 return ERR_PTR(-ENOMEM);
9472 jc->info = alloc_percpu(struct perf_cgroup_info);
9475 return ERR_PTR(-ENOMEM);
9481 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9483 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9485 free_percpu(jc->info);
9489 static int __perf_cgroup_move(void *info)
9491 struct task_struct *task = info;
9493 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9498 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9500 struct task_struct *task;
9501 struct cgroup_subsys_state *css;
9503 cgroup_taskset_for_each(task, css, tset)
9504 task_function_call(task, __perf_cgroup_move, task);
9507 struct cgroup_subsys perf_event_cgrp_subsys = {
9508 .css_alloc = perf_cgroup_css_alloc,
9509 .css_free = perf_cgroup_css_free,
9510 .attach = perf_cgroup_attach,
9512 #endif /* CONFIG_CGROUP_PERF */