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 WRITE_ONCE(event->oncpu, smp_processor_id());
1890 * Order event::oncpu write to happen before the ACTIVE state
1894 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE);
1897 * Unthrottle events, since we scheduled we might have missed several
1898 * ticks already, also for a heavily scheduling task there is little
1899 * guarantee it'll get a tick in a timely manner.
1901 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1902 perf_log_throttle(event, 1);
1903 event->hw.interrupts = 0;
1907 * The new state must be visible before we turn it on in the hardware:
1911 perf_pmu_disable(event->pmu);
1913 perf_set_shadow_time(event, ctx, tstamp);
1915 perf_log_itrace_start(event);
1917 if (event->pmu->add(event, PERF_EF_START)) {
1918 event->state = PERF_EVENT_STATE_INACTIVE;
1924 event->tstamp_running += tstamp - event->tstamp_stopped;
1926 if (!is_software_event(event))
1927 cpuctx->active_oncpu++;
1928 if (!ctx->nr_active++)
1929 perf_event_ctx_activate(ctx);
1930 if (event->attr.freq && event->attr.sample_freq)
1933 if (event->attr.exclusive)
1934 cpuctx->exclusive = 1;
1936 if (is_orphaned_child(event))
1937 schedule_orphans_remove(ctx);
1940 perf_pmu_enable(event->pmu);
1946 group_sched_in(struct perf_event *group_event,
1947 struct perf_cpu_context *cpuctx,
1948 struct perf_event_context *ctx)
1950 struct perf_event *event, *partial_group = NULL;
1951 struct pmu *pmu = ctx->pmu;
1952 u64 now = ctx->time;
1953 bool simulate = false;
1955 if (group_event->state == PERF_EVENT_STATE_OFF)
1958 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
1960 if (event_sched_in(group_event, cpuctx, ctx)) {
1961 pmu->cancel_txn(pmu);
1962 perf_mux_hrtimer_restart(cpuctx);
1967 * Schedule in siblings as one group (if any):
1969 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1970 if (event_sched_in(event, cpuctx, ctx)) {
1971 partial_group = event;
1976 if (!pmu->commit_txn(pmu))
1981 * Groups can be scheduled in as one unit only, so undo any
1982 * partial group before returning:
1983 * The events up to the failed event are scheduled out normally,
1984 * tstamp_stopped will be updated.
1986 * The failed events and the remaining siblings need to have
1987 * their timings updated as if they had gone thru event_sched_in()
1988 * and event_sched_out(). This is required to get consistent timings
1989 * across the group. This also takes care of the case where the group
1990 * could never be scheduled by ensuring tstamp_stopped is set to mark
1991 * the time the event was actually stopped, such that time delta
1992 * calculation in update_event_times() is correct.
1994 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1995 if (event == partial_group)
1999 event->tstamp_running += now - event->tstamp_stopped;
2000 event->tstamp_stopped = now;
2002 event_sched_out(event, cpuctx, ctx);
2005 event_sched_out(group_event, cpuctx, ctx);
2007 pmu->cancel_txn(pmu);
2009 perf_mux_hrtimer_restart(cpuctx);
2015 * Work out whether we can put this event group on the CPU now.
2017 static int group_can_go_on(struct perf_event *event,
2018 struct perf_cpu_context *cpuctx,
2022 * Groups consisting entirely of software events can always go on.
2024 if (event->group_flags & PERF_GROUP_SOFTWARE)
2027 * If an exclusive group is already on, no other hardware
2030 if (cpuctx->exclusive)
2033 * If this group is exclusive and there are already
2034 * events on the CPU, it can't go on.
2036 if (event->attr.exclusive && cpuctx->active_oncpu)
2039 * Otherwise, try to add it if all previous groups were able
2045 static void add_event_to_ctx(struct perf_event *event,
2046 struct perf_event_context *ctx)
2048 u64 tstamp = perf_event_time(event);
2050 list_add_event(event, ctx);
2051 perf_group_attach(event);
2052 event->tstamp_enabled = tstamp;
2053 event->tstamp_running = tstamp;
2054 event->tstamp_stopped = tstamp;
2057 static void task_ctx_sched_out(struct perf_event_context *ctx);
2059 ctx_sched_in(struct perf_event_context *ctx,
2060 struct perf_cpu_context *cpuctx,
2061 enum event_type_t event_type,
2062 struct task_struct *task);
2064 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2065 struct perf_event_context *ctx,
2066 struct task_struct *task)
2068 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2070 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2071 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2073 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2077 * Cross CPU call to install and enable a performance event
2079 * Must be called with ctx->mutex held
2081 static int __perf_install_in_context(void *info)
2083 struct perf_event *event = info;
2084 struct perf_event_context *ctx = event->ctx;
2085 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2086 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2087 struct task_struct *task = current;
2089 perf_ctx_lock(cpuctx, task_ctx);
2090 perf_pmu_disable(cpuctx->ctx.pmu);
2093 * If there was an active task_ctx schedule it out.
2096 task_ctx_sched_out(task_ctx);
2099 * If the context we're installing events in is not the
2100 * active task_ctx, flip them.
2102 if (ctx->task && task_ctx != ctx) {
2104 raw_spin_unlock(&task_ctx->lock);
2105 raw_spin_lock(&ctx->lock);
2110 cpuctx->task_ctx = task_ctx;
2111 task = task_ctx->task;
2114 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
2116 update_context_time(ctx);
2118 * update cgrp time only if current cgrp
2119 * matches event->cgrp. Must be done before
2120 * calling add_event_to_ctx()
2122 update_cgrp_time_from_event(event);
2124 add_event_to_ctx(event, ctx);
2127 * Schedule everything back in
2129 perf_event_sched_in(cpuctx, task_ctx, task);
2131 perf_pmu_enable(cpuctx->ctx.pmu);
2132 perf_ctx_unlock(cpuctx, task_ctx);
2138 * Attach a performance event to a context
2140 * First we add the event to the list with the hardware enable bit
2141 * in event->hw_config cleared.
2143 * If the event is attached to a task which is on a CPU we use a smp
2144 * call to enable it in the task context. The task might have been
2145 * scheduled away, but we check this in the smp call again.
2148 perf_install_in_context(struct perf_event_context *ctx,
2149 struct perf_event *event,
2152 struct task_struct *task = ctx->task;
2154 lockdep_assert_held(&ctx->mutex);
2157 if (event->cpu != -1)
2162 * Per cpu events are installed via an smp call and
2163 * the install is always successful.
2165 cpu_function_call(cpu, __perf_install_in_context, event);
2170 if (!task_function_call(task, __perf_install_in_context, event))
2173 raw_spin_lock_irq(&ctx->lock);
2175 * If we failed to find a running task, but find the context active now
2176 * that we've acquired the ctx->lock, retry.
2178 if (ctx->is_active) {
2179 raw_spin_unlock_irq(&ctx->lock);
2181 * Reload the task pointer, it might have been changed by
2182 * a concurrent perf_event_context_sched_out().
2189 * Since the task isn't running, its safe to add the event, us holding
2190 * the ctx->lock ensures the task won't get scheduled in.
2192 add_event_to_ctx(event, ctx);
2193 raw_spin_unlock_irq(&ctx->lock);
2197 * Put a event into inactive state and update time fields.
2198 * Enabling the leader of a group effectively enables all
2199 * the group members that aren't explicitly disabled, so we
2200 * have to update their ->tstamp_enabled also.
2201 * Note: this works for group members as well as group leaders
2202 * since the non-leader members' sibling_lists will be empty.
2204 static void __perf_event_mark_enabled(struct perf_event *event)
2206 struct perf_event *sub;
2207 u64 tstamp = perf_event_time(event);
2209 event->state = PERF_EVENT_STATE_INACTIVE;
2210 event->tstamp_enabled = tstamp - event->total_time_enabled;
2211 list_for_each_entry(sub, &event->sibling_list, group_entry) {
2212 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
2213 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
2218 * Cross CPU call to enable a performance event
2220 static int __perf_event_enable(void *info)
2222 struct perf_event *event = info;
2223 struct perf_event_context *ctx = event->ctx;
2224 struct perf_event *leader = event->group_leader;
2225 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2229 * There's a time window between 'ctx->is_active' check
2230 * in perf_event_enable function and this place having:
2232 * - ctx->lock unlocked
2234 * where the task could be killed and 'ctx' deactivated
2235 * by perf_event_exit_task.
2237 if (!ctx->is_active)
2240 raw_spin_lock(&ctx->lock);
2241 update_context_time(ctx);
2243 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2247 * set current task's cgroup time reference point
2249 perf_cgroup_set_timestamp(current, ctx);
2251 __perf_event_mark_enabled(event);
2253 if (!event_filter_match(event)) {
2254 if (is_cgroup_event(event))
2255 perf_cgroup_defer_enabled(event);
2260 * If the event is in a group and isn't the group leader,
2261 * then don't put it on unless the group is on.
2263 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2266 if (!group_can_go_on(event, cpuctx, 1)) {
2269 if (event == leader)
2270 err = group_sched_in(event, cpuctx, ctx);
2272 err = event_sched_in(event, cpuctx, ctx);
2277 * If this event can't go on and it's part of a
2278 * group, then the whole group has to come off.
2280 if (leader != event) {
2281 group_sched_out(leader, cpuctx, ctx);
2282 perf_mux_hrtimer_restart(cpuctx);
2284 if (leader->attr.pinned) {
2285 update_group_times(leader);
2286 leader->state = PERF_EVENT_STATE_ERROR;
2291 raw_spin_unlock(&ctx->lock);
2299 * If event->ctx is a cloned context, callers must make sure that
2300 * every task struct that event->ctx->task could possibly point to
2301 * remains valid. This condition is satisfied when called through
2302 * perf_event_for_each_child or perf_event_for_each as described
2303 * for perf_event_disable.
2305 static void _perf_event_enable(struct perf_event *event)
2307 struct perf_event_context *ctx = event->ctx;
2308 struct task_struct *task = ctx->task;
2312 * Enable the event on the cpu that it's on
2314 cpu_function_call(event->cpu, __perf_event_enable, event);
2318 raw_spin_lock_irq(&ctx->lock);
2319 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2323 * If the event is in error state, clear that first.
2324 * That way, if we see the event in error state below, we
2325 * know that it has gone back into error state, as distinct
2326 * from the task having been scheduled away before the
2327 * cross-call arrived.
2329 if (event->state == PERF_EVENT_STATE_ERROR)
2330 event->state = PERF_EVENT_STATE_OFF;
2333 if (!ctx->is_active) {
2334 __perf_event_mark_enabled(event);
2338 raw_spin_unlock_irq(&ctx->lock);
2340 if (!task_function_call(task, __perf_event_enable, event))
2343 raw_spin_lock_irq(&ctx->lock);
2346 * If the context is active and the event is still off,
2347 * we need to retry the cross-call.
2349 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2351 * task could have been flipped by a concurrent
2352 * perf_event_context_sched_out()
2359 raw_spin_unlock_irq(&ctx->lock);
2363 * See perf_event_disable();
2365 void perf_event_enable(struct perf_event *event)
2367 struct perf_event_context *ctx;
2369 ctx = perf_event_ctx_lock(event);
2370 _perf_event_enable(event);
2371 perf_event_ctx_unlock(event, ctx);
2373 EXPORT_SYMBOL_GPL(perf_event_enable);
2375 static int __perf_event_stop(void *info)
2377 struct perf_event *event = info;
2379 /* for AUX events, our job is done if the event is already inactive */
2380 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2383 /* matches smp_wmb() in event_sched_in() */
2387 * There is a window with interrupts enabled before we get here,
2388 * so we need to check again lest we try to stop another CPU's event.
2390 if (READ_ONCE(event->oncpu) != smp_processor_id())
2393 event->pmu->stop(event, PERF_EF_UPDATE);
2398 static int _perf_event_refresh(struct perf_event *event, int refresh)
2401 * not supported on inherited events
2403 if (event->attr.inherit || !is_sampling_event(event))
2406 atomic_add(refresh, &event->event_limit);
2407 _perf_event_enable(event);
2413 * See perf_event_disable()
2415 int perf_event_refresh(struct perf_event *event, int refresh)
2417 struct perf_event_context *ctx;
2420 ctx = perf_event_ctx_lock(event);
2421 ret = _perf_event_refresh(event, refresh);
2422 perf_event_ctx_unlock(event, ctx);
2426 EXPORT_SYMBOL_GPL(perf_event_refresh);
2428 static void ctx_sched_out(struct perf_event_context *ctx,
2429 struct perf_cpu_context *cpuctx,
2430 enum event_type_t event_type)
2432 struct perf_event *event;
2433 int is_active = ctx->is_active;
2435 ctx->is_active &= ~event_type;
2436 if (likely(!ctx->nr_events))
2439 update_context_time(ctx);
2440 update_cgrp_time_from_cpuctx(cpuctx);
2441 if (!ctx->nr_active)
2444 perf_pmu_disable(ctx->pmu);
2445 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2446 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2447 group_sched_out(event, cpuctx, ctx);
2450 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2451 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2452 group_sched_out(event, cpuctx, ctx);
2454 perf_pmu_enable(ctx->pmu);
2458 * Test whether two contexts are equivalent, i.e. whether they have both been
2459 * cloned from the same version of the same context.
2461 * Equivalence is measured using a generation number in the context that is
2462 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2463 * and list_del_event().
2465 static int context_equiv(struct perf_event_context *ctx1,
2466 struct perf_event_context *ctx2)
2468 lockdep_assert_held(&ctx1->lock);
2469 lockdep_assert_held(&ctx2->lock);
2471 /* Pinning disables the swap optimization */
2472 if (ctx1->pin_count || ctx2->pin_count)
2475 /* If ctx1 is the parent of ctx2 */
2476 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2479 /* If ctx2 is the parent of ctx1 */
2480 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2484 * If ctx1 and ctx2 have the same parent; we flatten the parent
2485 * hierarchy, see perf_event_init_context().
2487 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2488 ctx1->parent_gen == ctx2->parent_gen)
2495 static void __perf_event_sync_stat(struct perf_event *event,
2496 struct perf_event *next_event)
2500 if (!event->attr.inherit_stat)
2504 * Update the event value, we cannot use perf_event_read()
2505 * because we're in the middle of a context switch and have IRQs
2506 * disabled, which upsets smp_call_function_single(), however
2507 * we know the event must be on the current CPU, therefore we
2508 * don't need to use it.
2510 switch (event->state) {
2511 case PERF_EVENT_STATE_ACTIVE:
2512 event->pmu->read(event);
2515 case PERF_EVENT_STATE_INACTIVE:
2516 update_event_times(event);
2524 * In order to keep per-task stats reliable we need to flip the event
2525 * values when we flip the contexts.
2527 value = local64_read(&next_event->count);
2528 value = local64_xchg(&event->count, value);
2529 local64_set(&next_event->count, value);
2531 swap(event->total_time_enabled, next_event->total_time_enabled);
2532 swap(event->total_time_running, next_event->total_time_running);
2535 * Since we swizzled the values, update the user visible data too.
2537 perf_event_update_userpage(event);
2538 perf_event_update_userpage(next_event);
2541 static void perf_event_sync_stat(struct perf_event_context *ctx,
2542 struct perf_event_context *next_ctx)
2544 struct perf_event *event, *next_event;
2549 update_context_time(ctx);
2551 event = list_first_entry(&ctx->event_list,
2552 struct perf_event, event_entry);
2554 next_event = list_first_entry(&next_ctx->event_list,
2555 struct perf_event, event_entry);
2557 while (&event->event_entry != &ctx->event_list &&
2558 &next_event->event_entry != &next_ctx->event_list) {
2560 __perf_event_sync_stat(event, next_event);
2562 event = list_next_entry(event, event_entry);
2563 next_event = list_next_entry(next_event, event_entry);
2567 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2568 struct task_struct *next)
2570 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2571 struct perf_event_context *next_ctx;
2572 struct perf_event_context *parent, *next_parent;
2573 struct perf_cpu_context *cpuctx;
2579 cpuctx = __get_cpu_context(ctx);
2580 if (!cpuctx->task_ctx)
2584 next_ctx = next->perf_event_ctxp[ctxn];
2588 parent = rcu_dereference(ctx->parent_ctx);
2589 next_parent = rcu_dereference(next_ctx->parent_ctx);
2591 /* If neither context have a parent context; they cannot be clones. */
2592 if (!parent && !next_parent)
2595 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
2597 * Looks like the two contexts are clones, so we might be
2598 * able to optimize the context switch. We lock both
2599 * contexts and check that they are clones under the
2600 * lock (including re-checking that neither has been
2601 * uncloned in the meantime). It doesn't matter which
2602 * order we take the locks because no other cpu could
2603 * be trying to lock both of these tasks.
2605 raw_spin_lock(&ctx->lock);
2606 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2607 if (context_equiv(ctx, next_ctx)) {
2609 * XXX do we need a memory barrier of sorts
2610 * wrt to rcu_dereference() of perf_event_ctxp
2612 task->perf_event_ctxp[ctxn] = next_ctx;
2613 next->perf_event_ctxp[ctxn] = ctx;
2615 next_ctx->task = task;
2617 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
2621 perf_event_sync_stat(ctx, next_ctx);
2623 raw_spin_unlock(&next_ctx->lock);
2624 raw_spin_unlock(&ctx->lock);
2630 raw_spin_lock(&ctx->lock);
2631 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2632 cpuctx->task_ctx = NULL;
2633 raw_spin_unlock(&ctx->lock);
2637 void perf_sched_cb_dec(struct pmu *pmu)
2639 this_cpu_dec(perf_sched_cb_usages);
2642 void perf_sched_cb_inc(struct pmu *pmu)
2644 this_cpu_inc(perf_sched_cb_usages);
2648 * This function provides the context switch callback to the lower code
2649 * layer. It is invoked ONLY when the context switch callback is enabled.
2651 static void perf_pmu_sched_task(struct task_struct *prev,
2652 struct task_struct *next,
2655 struct perf_cpu_context *cpuctx;
2657 unsigned long flags;
2662 local_irq_save(flags);
2666 list_for_each_entry_rcu(pmu, &pmus, entry) {
2667 if (pmu->sched_task) {
2668 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2670 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2672 perf_pmu_disable(pmu);
2674 pmu->sched_task(cpuctx->task_ctx, sched_in);
2676 perf_pmu_enable(pmu);
2678 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2684 local_irq_restore(flags);
2687 static void perf_event_switch(struct task_struct *task,
2688 struct task_struct *next_prev, bool sched_in);
2690 #define for_each_task_context_nr(ctxn) \
2691 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2694 * Called from scheduler to remove the events of the current task,
2695 * with interrupts disabled.
2697 * We stop each event and update the event value in event->count.
2699 * This does not protect us against NMI, but disable()
2700 * sets the disabled bit in the control field of event _before_
2701 * accessing the event control register. If a NMI hits, then it will
2702 * not restart the event.
2704 void __perf_event_task_sched_out(struct task_struct *task,
2705 struct task_struct *next)
2709 if (__this_cpu_read(perf_sched_cb_usages))
2710 perf_pmu_sched_task(task, next, false);
2712 if (atomic_read(&nr_switch_events))
2713 perf_event_switch(task, next, false);
2715 for_each_task_context_nr(ctxn)
2716 perf_event_context_sched_out(task, ctxn, next);
2719 * if cgroup events exist on this CPU, then we need
2720 * to check if we have to switch out PMU state.
2721 * cgroup event are system-wide mode only
2723 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2724 perf_cgroup_sched_out(task, next);
2727 static void task_ctx_sched_out(struct perf_event_context *ctx)
2729 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2731 if (!cpuctx->task_ctx)
2734 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2737 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2738 cpuctx->task_ctx = NULL;
2742 * Called with IRQs disabled
2744 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2745 enum event_type_t event_type)
2747 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2751 ctx_pinned_sched_in(struct perf_event_context *ctx,
2752 struct perf_cpu_context *cpuctx)
2754 struct perf_event *event;
2756 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2757 if (event->state <= PERF_EVENT_STATE_OFF)
2759 if (!event_filter_match(event))
2762 /* may need to reset tstamp_enabled */
2763 if (is_cgroup_event(event))
2764 perf_cgroup_mark_enabled(event, ctx);
2766 if (group_can_go_on(event, cpuctx, 1))
2767 group_sched_in(event, cpuctx, ctx);
2770 * If this pinned group hasn't been scheduled,
2771 * put it in error state.
2773 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2774 update_group_times(event);
2775 event->state = PERF_EVENT_STATE_ERROR;
2781 ctx_flexible_sched_in(struct perf_event_context *ctx,
2782 struct perf_cpu_context *cpuctx)
2784 struct perf_event *event;
2787 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2788 /* Ignore events in OFF or ERROR state */
2789 if (event->state <= PERF_EVENT_STATE_OFF)
2792 * Listen to the 'cpu' scheduling filter constraint
2795 if (!event_filter_match(event))
2798 /* may need to reset tstamp_enabled */
2799 if (is_cgroup_event(event))
2800 perf_cgroup_mark_enabled(event, ctx);
2802 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2803 if (group_sched_in(event, cpuctx, ctx))
2810 ctx_sched_in(struct perf_event_context *ctx,
2811 struct perf_cpu_context *cpuctx,
2812 enum event_type_t event_type,
2813 struct task_struct *task)
2816 int is_active = ctx->is_active;
2818 ctx->is_active |= event_type;
2819 if (likely(!ctx->nr_events))
2823 ctx->timestamp = now;
2824 perf_cgroup_set_timestamp(task, ctx);
2826 * First go through the list and put on any pinned groups
2827 * in order to give them the best chance of going on.
2829 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2830 ctx_pinned_sched_in(ctx, cpuctx);
2832 /* Then walk through the lower prio flexible groups */
2833 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2834 ctx_flexible_sched_in(ctx, cpuctx);
2837 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2838 enum event_type_t event_type,
2839 struct task_struct *task)
2841 struct perf_event_context *ctx = &cpuctx->ctx;
2843 ctx_sched_in(ctx, cpuctx, event_type, task);
2846 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2847 struct task_struct *task)
2849 struct perf_cpu_context *cpuctx;
2851 cpuctx = __get_cpu_context(ctx);
2852 if (cpuctx->task_ctx == ctx)
2855 perf_ctx_lock(cpuctx, ctx);
2856 perf_pmu_disable(ctx->pmu);
2858 * We want to keep the following priority order:
2859 * cpu pinned (that don't need to move), task pinned,
2860 * cpu flexible, task flexible.
2862 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2865 cpuctx->task_ctx = ctx;
2867 perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2869 perf_pmu_enable(ctx->pmu);
2870 perf_ctx_unlock(cpuctx, ctx);
2874 * Called from scheduler to add the events of the current task
2875 * with interrupts disabled.
2877 * We restore the event value and then enable it.
2879 * This does not protect us against NMI, but enable()
2880 * sets the enabled bit in the control field of event _before_
2881 * accessing the event control register. If a NMI hits, then it will
2882 * keep the event running.
2884 void __perf_event_task_sched_in(struct task_struct *prev,
2885 struct task_struct *task)
2887 struct perf_event_context *ctx;
2890 for_each_task_context_nr(ctxn) {
2891 ctx = task->perf_event_ctxp[ctxn];
2895 perf_event_context_sched_in(ctx, task);
2898 * if cgroup events exist on this CPU, then we need
2899 * to check if we have to switch in PMU state.
2900 * cgroup event are system-wide mode only
2902 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
2903 perf_cgroup_sched_in(prev, task);
2905 if (atomic_read(&nr_switch_events))
2906 perf_event_switch(task, prev, true);
2908 if (__this_cpu_read(perf_sched_cb_usages))
2909 perf_pmu_sched_task(prev, task, true);
2912 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2914 u64 frequency = event->attr.sample_freq;
2915 u64 sec = NSEC_PER_SEC;
2916 u64 divisor, dividend;
2918 int count_fls, nsec_fls, frequency_fls, sec_fls;
2920 count_fls = fls64(count);
2921 nsec_fls = fls64(nsec);
2922 frequency_fls = fls64(frequency);
2926 * We got @count in @nsec, with a target of sample_freq HZ
2927 * the target period becomes:
2930 * period = -------------------
2931 * @nsec * sample_freq
2936 * Reduce accuracy by one bit such that @a and @b converge
2937 * to a similar magnitude.
2939 #define REDUCE_FLS(a, b) \
2941 if (a##_fls > b##_fls) { \
2951 * Reduce accuracy until either term fits in a u64, then proceed with
2952 * the other, so that finally we can do a u64/u64 division.
2954 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2955 REDUCE_FLS(nsec, frequency);
2956 REDUCE_FLS(sec, count);
2959 if (count_fls + sec_fls > 64) {
2960 divisor = nsec * frequency;
2962 while (count_fls + sec_fls > 64) {
2963 REDUCE_FLS(count, sec);
2967 dividend = count * sec;
2969 dividend = count * sec;
2971 while (nsec_fls + frequency_fls > 64) {
2972 REDUCE_FLS(nsec, frequency);
2976 divisor = nsec * frequency;
2982 return div64_u64(dividend, divisor);
2985 static DEFINE_PER_CPU(int, perf_throttled_count);
2986 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2988 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2990 struct hw_perf_event *hwc = &event->hw;
2991 s64 period, sample_period;
2994 period = perf_calculate_period(event, nsec, count);
2996 delta = (s64)(period - hwc->sample_period);
2997 delta = (delta + 7) / 8; /* low pass filter */
2999 sample_period = hwc->sample_period + delta;
3004 hwc->sample_period = sample_period;
3006 if (local64_read(&hwc->period_left) > 8*sample_period) {
3008 event->pmu->stop(event, PERF_EF_UPDATE);
3010 local64_set(&hwc->period_left, 0);
3013 event->pmu->start(event, PERF_EF_RELOAD);
3018 * combine freq adjustment with unthrottling to avoid two passes over the
3019 * events. At the same time, make sure, having freq events does not change
3020 * the rate of unthrottling as that would introduce bias.
3022 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3025 struct perf_event *event;
3026 struct hw_perf_event *hwc;
3027 u64 now, period = TICK_NSEC;
3031 * only need to iterate over all events iff:
3032 * - context have events in frequency mode (needs freq adjust)
3033 * - there are events to unthrottle on this cpu
3035 if (!(ctx->nr_freq || needs_unthr))
3038 raw_spin_lock(&ctx->lock);
3039 perf_pmu_disable(ctx->pmu);
3041 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3042 if (event->state != PERF_EVENT_STATE_ACTIVE)
3045 if (!event_filter_match(event))
3048 perf_pmu_disable(event->pmu);
3052 if (hwc->interrupts == MAX_INTERRUPTS) {
3053 hwc->interrupts = 0;
3054 perf_log_throttle(event, 1);
3055 event->pmu->start(event, 0);
3058 if (!event->attr.freq || !event->attr.sample_freq)
3062 * stop the event and update event->count
3064 event->pmu->stop(event, PERF_EF_UPDATE);
3066 now = local64_read(&event->count);
3067 delta = now - hwc->freq_count_stamp;
3068 hwc->freq_count_stamp = now;
3072 * reload only if value has changed
3073 * we have stopped the event so tell that
3074 * to perf_adjust_period() to avoid stopping it
3078 perf_adjust_period(event, period, delta, false);
3080 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3082 perf_pmu_enable(event->pmu);
3085 perf_pmu_enable(ctx->pmu);
3086 raw_spin_unlock(&ctx->lock);
3090 * Round-robin a context's events:
3092 static void rotate_ctx(struct perf_event_context *ctx)
3095 * Rotate the first entry last of non-pinned groups. Rotation might be
3096 * disabled by the inheritance code.
3098 if (!ctx->rotate_disable)
3099 list_rotate_left(&ctx->flexible_groups);
3102 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
3104 struct perf_event_context *ctx = NULL;
3107 if (cpuctx->ctx.nr_events) {
3108 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3112 ctx = cpuctx->task_ctx;
3113 if (ctx && ctx->nr_events) {
3114 if (ctx->nr_events != ctx->nr_active)
3121 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3122 perf_pmu_disable(cpuctx->ctx.pmu);
3124 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3126 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3128 rotate_ctx(&cpuctx->ctx);
3132 perf_event_sched_in(cpuctx, ctx, current);
3134 perf_pmu_enable(cpuctx->ctx.pmu);
3135 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3141 #ifdef CONFIG_NO_HZ_FULL
3142 bool perf_event_can_stop_tick(void)
3144 if (atomic_read(&nr_freq_events) ||
3145 __this_cpu_read(perf_throttled_count))
3152 void perf_event_task_tick(void)
3154 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3155 struct perf_event_context *ctx, *tmp;
3158 WARN_ON(!irqs_disabled());
3160 __this_cpu_inc(perf_throttled_seq);
3161 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3163 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3164 perf_adjust_freq_unthr_context(ctx, throttled);
3167 static int event_enable_on_exec(struct perf_event *event,
3168 struct perf_event_context *ctx)
3170 if (!event->attr.enable_on_exec)
3173 event->attr.enable_on_exec = 0;
3174 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3177 __perf_event_mark_enabled(event);
3183 * Enable all of a task's events that have been marked enable-on-exec.
3184 * This expects task == current.
3186 static void perf_event_enable_on_exec(int ctxn)
3188 struct perf_event_context *ctx, *clone_ctx = NULL;
3189 struct perf_event *event;
3190 unsigned long flags;
3194 local_irq_save(flags);
3195 ctx = current->perf_event_ctxp[ctxn];
3196 if (!ctx || !ctx->nr_events)
3200 * We must ctxsw out cgroup events to avoid conflict
3201 * when invoking perf_task_event_sched_in() later on
3202 * in this function. Otherwise we end up trying to
3203 * ctxswin cgroup events which are already scheduled
3206 perf_cgroup_sched_out(current, NULL);
3208 raw_spin_lock(&ctx->lock);
3209 task_ctx_sched_out(ctx);
3211 list_for_each_entry(event, &ctx->event_list, event_entry) {
3212 ret = event_enable_on_exec(event, ctx);
3218 * Unclone this context if we enabled any event.
3221 clone_ctx = unclone_ctx(ctx);
3223 raw_spin_unlock(&ctx->lock);
3226 * Also calls ctxswin for cgroup events, if any:
3228 perf_event_context_sched_in(ctx, ctx->task);
3230 local_irq_restore(flags);
3236 void perf_event_exec(void)
3241 for_each_task_context_nr(ctxn)
3242 perf_event_enable_on_exec(ctxn);
3246 struct perf_read_data {
3247 struct perf_event *event;
3253 * Cross CPU call to read the hardware event
3255 static void __perf_event_read(void *info)
3257 struct perf_read_data *data = info;
3258 struct perf_event *sub, *event = data->event;
3259 struct perf_event_context *ctx = event->ctx;
3260 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3261 struct pmu *pmu = event->pmu;
3264 * If this is a task context, we need to check whether it is
3265 * the current task context of this cpu. If not it has been
3266 * scheduled out before the smp call arrived. In that case
3267 * event->count would have been updated to a recent sample
3268 * when the event was scheduled out.
3270 if (ctx->task && cpuctx->task_ctx != ctx)
3273 raw_spin_lock(&ctx->lock);
3274 if (ctx->is_active) {
3275 update_context_time(ctx);
3276 update_cgrp_time_from_event(event);
3279 update_event_times(event);
3280 if (event->state != PERF_EVENT_STATE_ACTIVE)
3289 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3293 list_for_each_entry(sub, &event->sibling_list, group_entry) {
3294 update_event_times(sub);
3295 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3297 * Use sibling's PMU rather than @event's since
3298 * sibling could be on different (eg: software) PMU.
3300 sub->pmu->read(sub);
3304 data->ret = pmu->commit_txn(pmu);
3307 raw_spin_unlock(&ctx->lock);
3310 static inline u64 perf_event_count(struct perf_event *event)
3312 if (event->pmu->count)
3313 return event->pmu->count(event);
3315 return __perf_event_count(event);
3319 * NMI-safe method to read a local event, that is an event that
3321 * - either for the current task, or for this CPU
3322 * - does not have inherit set, for inherited task events
3323 * will not be local and we cannot read them atomically
3324 * - must not have a pmu::count method
3326 u64 perf_event_read_local(struct perf_event *event)
3328 unsigned long flags;
3332 * Disabling interrupts avoids all counter scheduling (context
3333 * switches, timer based rotation and IPIs).
3335 local_irq_save(flags);
3337 /* If this is a per-task event, it must be for current */
3338 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
3339 event->hw.target != current);
3341 /* If this is a per-CPU event, it must be for this CPU */
3342 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
3343 event->cpu != smp_processor_id());
3346 * It must not be an event with inherit set, we cannot read
3347 * all child counters from atomic context.
3349 WARN_ON_ONCE(event->attr.inherit);
3352 * It must not have a pmu::count method, those are not
3355 WARN_ON_ONCE(event->pmu->count);
3358 * If the event is currently on this CPU, its either a per-task event,
3359 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3362 if (event->oncpu == smp_processor_id())
3363 event->pmu->read(event);
3365 val = local64_read(&event->count);
3366 local_irq_restore(flags);
3371 static int perf_event_read(struct perf_event *event, bool group)
3376 * If event is enabled and currently active on a CPU, update the
3377 * value in the event structure:
3379 if (event->state == PERF_EVENT_STATE_ACTIVE) {
3380 struct perf_read_data data = {
3385 smp_call_function_single(event->oncpu,
3386 __perf_event_read, &data, 1);
3388 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
3389 struct perf_event_context *ctx = event->ctx;
3390 unsigned long flags;
3392 raw_spin_lock_irqsave(&ctx->lock, flags);
3394 * may read while context is not active
3395 * (e.g., thread is blocked), in that case
3396 * we cannot update context time
3398 if (ctx->is_active) {
3399 update_context_time(ctx);
3400 update_cgrp_time_from_event(event);
3403 update_group_times(event);
3405 update_event_times(event);
3406 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3413 * Initialize the perf_event context in a task_struct:
3415 static void __perf_event_init_context(struct perf_event_context *ctx)
3417 raw_spin_lock_init(&ctx->lock);
3418 mutex_init(&ctx->mutex);
3419 INIT_LIST_HEAD(&ctx->active_ctx_list);
3420 INIT_LIST_HEAD(&ctx->pinned_groups);
3421 INIT_LIST_HEAD(&ctx->flexible_groups);
3422 INIT_LIST_HEAD(&ctx->event_list);
3423 atomic_set(&ctx->refcount, 1);
3424 INIT_DELAYED_WORK(&ctx->orphans_remove, orphans_remove_work);
3427 static struct perf_event_context *
3428 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
3430 struct perf_event_context *ctx;
3432 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
3436 __perf_event_init_context(ctx);
3439 get_task_struct(task);
3446 static struct task_struct *
3447 find_lively_task_by_vpid(pid_t vpid)
3449 struct task_struct *task;
3455 task = find_task_by_vpid(vpid);
3457 get_task_struct(task);
3461 return ERR_PTR(-ESRCH);
3467 * Returns a matching context with refcount and pincount.
3469 static struct perf_event_context *
3470 find_get_context(struct pmu *pmu, struct task_struct *task,
3471 struct perf_event *event)
3473 struct perf_event_context *ctx, *clone_ctx = NULL;
3474 struct perf_cpu_context *cpuctx;
3475 void *task_ctx_data = NULL;
3476 unsigned long flags;
3478 int cpu = event->cpu;
3481 /* Must be root to operate on a CPU event: */
3482 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3483 return ERR_PTR(-EACCES);
3486 * We could be clever and allow to attach a event to an
3487 * offline CPU and activate it when the CPU comes up, but
3490 if (!cpu_online(cpu))
3491 return ERR_PTR(-ENODEV);
3493 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3502 ctxn = pmu->task_ctx_nr;
3506 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
3507 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
3508 if (!task_ctx_data) {
3515 ctx = perf_lock_task_context(task, ctxn, &flags);
3517 clone_ctx = unclone_ctx(ctx);
3520 if (task_ctx_data && !ctx->task_ctx_data) {
3521 ctx->task_ctx_data = task_ctx_data;
3522 task_ctx_data = NULL;
3524 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3529 ctx = alloc_perf_context(pmu, task);
3534 if (task_ctx_data) {
3535 ctx->task_ctx_data = task_ctx_data;
3536 task_ctx_data = NULL;
3540 mutex_lock(&task->perf_event_mutex);
3542 * If it has already passed perf_event_exit_task().
3543 * we must see PF_EXITING, it takes this mutex too.
3545 if (task->flags & PF_EXITING)
3547 else if (task->perf_event_ctxp[ctxn])
3552 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3554 mutex_unlock(&task->perf_event_mutex);
3556 if (unlikely(err)) {
3565 kfree(task_ctx_data);
3569 kfree(task_ctx_data);
3570 return ERR_PTR(err);
3573 static void perf_event_free_filter(struct perf_event *event);
3574 static void perf_event_free_bpf_prog(struct perf_event *event);
3576 static void free_event_rcu(struct rcu_head *head)
3578 struct perf_event *event;
3580 event = container_of(head, struct perf_event, rcu_head);
3582 put_pid_ns(event->ns);
3583 perf_event_free_filter(event);
3587 static void ring_buffer_attach(struct perf_event *event,
3588 struct ring_buffer *rb);
3590 static void unaccount_event_cpu(struct perf_event *event, int cpu)
3595 if (is_cgroup_event(event))
3596 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
3599 static void unaccount_event(struct perf_event *event)
3604 if (event->attach_state & PERF_ATTACH_TASK)
3605 static_key_slow_dec_deferred(&perf_sched_events);
3606 if (event->attr.mmap || event->attr.mmap_data)
3607 atomic_dec(&nr_mmap_events);
3608 if (event->attr.comm)
3609 atomic_dec(&nr_comm_events);
3610 if (event->attr.task)
3611 atomic_dec(&nr_task_events);
3612 if (event->attr.freq)
3613 atomic_dec(&nr_freq_events);
3614 if (event->attr.context_switch) {
3615 static_key_slow_dec_deferred(&perf_sched_events);
3616 atomic_dec(&nr_switch_events);
3618 if (is_cgroup_event(event))
3619 static_key_slow_dec_deferred(&perf_sched_events);
3620 if (has_branch_stack(event))
3621 static_key_slow_dec_deferred(&perf_sched_events);
3623 unaccount_event_cpu(event, event->cpu);
3627 * The following implement mutual exclusion of events on "exclusive" pmus
3628 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
3629 * at a time, so we disallow creating events that might conflict, namely:
3631 * 1) cpu-wide events in the presence of per-task events,
3632 * 2) per-task events in the presence of cpu-wide events,
3633 * 3) two matching events on the same context.
3635 * The former two cases are handled in the allocation path (perf_event_alloc(),
3636 * __free_event()), the latter -- before the first perf_install_in_context().
3638 static int exclusive_event_init(struct perf_event *event)
3640 struct pmu *pmu = event->pmu;
3642 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3646 * Prevent co-existence of per-task and cpu-wide events on the
3647 * same exclusive pmu.
3649 * Negative pmu::exclusive_cnt means there are cpu-wide
3650 * events on this "exclusive" pmu, positive means there are
3653 * Since this is called in perf_event_alloc() path, event::ctx
3654 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
3655 * to mean "per-task event", because unlike other attach states it
3656 * never gets cleared.
3658 if (event->attach_state & PERF_ATTACH_TASK) {
3659 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
3662 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
3669 static void exclusive_event_destroy(struct perf_event *event)
3671 struct pmu *pmu = event->pmu;
3673 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3676 /* see comment in exclusive_event_init() */
3677 if (event->attach_state & PERF_ATTACH_TASK)
3678 atomic_dec(&pmu->exclusive_cnt);
3680 atomic_inc(&pmu->exclusive_cnt);
3683 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
3685 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) &&
3686 (e1->cpu == e2->cpu ||
3693 /* Called under the same ctx::mutex as perf_install_in_context() */
3694 static bool exclusive_event_installable(struct perf_event *event,
3695 struct perf_event_context *ctx)
3697 struct perf_event *iter_event;
3698 struct pmu *pmu = event->pmu;
3700 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
3703 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
3704 if (exclusive_event_match(iter_event, event))
3711 static void __free_event(struct perf_event *event)
3713 if (!event->parent) {
3714 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3715 put_callchain_buffers();
3718 perf_event_free_bpf_prog(event);
3721 event->destroy(event);
3724 put_ctx(event->ctx);
3727 exclusive_event_destroy(event);
3728 module_put(event->pmu->module);
3731 call_rcu(&event->rcu_head, free_event_rcu);
3734 static void _free_event(struct perf_event *event)
3736 irq_work_sync(&event->pending);
3738 unaccount_event(event);
3742 * Can happen when we close an event with re-directed output.
3744 * Since we have a 0 refcount, perf_mmap_close() will skip
3745 * over us; possibly making our ring_buffer_put() the last.
3747 mutex_lock(&event->mmap_mutex);
3748 ring_buffer_attach(event, NULL);
3749 mutex_unlock(&event->mmap_mutex);
3752 if (is_cgroup_event(event))
3753 perf_detach_cgroup(event);
3755 __free_event(event);
3759 * Used to free events which have a known refcount of 1, such as in error paths
3760 * where the event isn't exposed yet and inherited events.
3762 static void free_event(struct perf_event *event)
3764 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
3765 "unexpected event refcount: %ld; ptr=%p\n",
3766 atomic_long_read(&event->refcount), event)) {
3767 /* leak to avoid use-after-free */
3775 * Remove user event from the owner task.
3777 static void perf_remove_from_owner(struct perf_event *event)
3779 struct task_struct *owner;
3782 owner = ACCESS_ONCE(event->owner);
3784 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3785 * !owner it means the list deletion is complete and we can indeed
3786 * free this event, otherwise we need to serialize on
3787 * owner->perf_event_mutex.
3789 smp_read_barrier_depends();
3792 * Since delayed_put_task_struct() also drops the last
3793 * task reference we can safely take a new reference
3794 * while holding the rcu_read_lock().
3796 get_task_struct(owner);
3802 * If we're here through perf_event_exit_task() we're already
3803 * holding ctx->mutex which would be an inversion wrt. the
3804 * normal lock order.
3806 * However we can safely take this lock because its the child
3809 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
3812 * We have to re-check the event->owner field, if it is cleared
3813 * we raced with perf_event_exit_task(), acquiring the mutex
3814 * ensured they're done, and we can proceed with freeing the
3818 list_del_init(&event->owner_entry);
3819 mutex_unlock(&owner->perf_event_mutex);
3820 put_task_struct(owner);
3824 static void put_event(struct perf_event *event)
3826 struct perf_event_context *ctx;
3828 if (!atomic_long_dec_and_test(&event->refcount))
3831 if (!is_kernel_event(event))
3832 perf_remove_from_owner(event);
3835 * There are two ways this annotation is useful:
3837 * 1) there is a lock recursion from perf_event_exit_task
3838 * see the comment there.
3840 * 2) there is a lock-inversion with mmap_sem through
3841 * perf_read_group(), which takes faults while
3842 * holding ctx->mutex, however this is called after
3843 * the last filedesc died, so there is no possibility
3844 * to trigger the AB-BA case.
3846 ctx = perf_event_ctx_lock_nested(event, SINGLE_DEPTH_NESTING);
3847 WARN_ON_ONCE(ctx->parent_ctx);
3848 perf_remove_from_context(event, true);
3849 perf_event_ctx_unlock(event, ctx);
3854 int perf_event_release_kernel(struct perf_event *event)
3859 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3862 * Called when the last reference to the file is gone.
3864 static int perf_release(struct inode *inode, struct file *file)
3866 put_event(file->private_data);
3871 * Remove all orphanes events from the context.
3873 static void orphans_remove_work(struct work_struct *work)
3875 struct perf_event_context *ctx;
3876 struct perf_event *event, *tmp;
3878 ctx = container_of(work, struct perf_event_context,
3879 orphans_remove.work);
3881 mutex_lock(&ctx->mutex);
3882 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) {
3883 struct perf_event *parent_event = event->parent;
3885 if (!is_orphaned_child(event))
3888 perf_remove_from_context(event, true);
3890 mutex_lock(&parent_event->child_mutex);
3891 list_del_init(&event->child_list);
3892 mutex_unlock(&parent_event->child_mutex);
3895 put_event(parent_event);
3898 raw_spin_lock_irq(&ctx->lock);
3899 ctx->orphans_remove_sched = false;
3900 raw_spin_unlock_irq(&ctx->lock);
3901 mutex_unlock(&ctx->mutex);
3906 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3908 struct perf_event *child;
3914 mutex_lock(&event->child_mutex);
3916 (void)perf_event_read(event, false);
3917 total += perf_event_count(event);
3919 *enabled += event->total_time_enabled +
3920 atomic64_read(&event->child_total_time_enabled);
3921 *running += event->total_time_running +
3922 atomic64_read(&event->child_total_time_running);
3924 list_for_each_entry(child, &event->child_list, child_list) {
3925 (void)perf_event_read(child, false);
3926 total += perf_event_count(child);
3927 *enabled += child->total_time_enabled;
3928 *running += child->total_time_running;
3930 mutex_unlock(&event->child_mutex);
3934 EXPORT_SYMBOL_GPL(perf_event_read_value);
3936 static int __perf_read_group_add(struct perf_event *leader,
3937 u64 read_format, u64 *values)
3939 struct perf_event *sub;
3940 int n = 1; /* skip @nr */
3943 ret = perf_event_read(leader, true);
3948 * Since we co-schedule groups, {enabled,running} times of siblings
3949 * will be identical to those of the leader, so we only publish one
3952 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3953 values[n++] += leader->total_time_enabled +
3954 atomic64_read(&leader->child_total_time_enabled);
3957 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3958 values[n++] += leader->total_time_running +
3959 atomic64_read(&leader->child_total_time_running);
3963 * Write {count,id} tuples for every sibling.
3965 values[n++] += perf_event_count(leader);
3966 if (read_format & PERF_FORMAT_ID)
3967 values[n++] = primary_event_id(leader);
3969 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3970 values[n++] += perf_event_count(sub);
3971 if (read_format & PERF_FORMAT_ID)
3972 values[n++] = primary_event_id(sub);
3978 static int perf_read_group(struct perf_event *event,
3979 u64 read_format, char __user *buf)
3981 struct perf_event *leader = event->group_leader, *child;
3982 struct perf_event_context *ctx = leader->ctx;
3986 lockdep_assert_held(&ctx->mutex);
3988 values = kzalloc(event->read_size, GFP_KERNEL);
3992 values[0] = 1 + leader->nr_siblings;
3995 * By locking the child_mutex of the leader we effectively
3996 * lock the child list of all siblings.. XXX explain how.
3998 mutex_lock(&leader->child_mutex);
4000 ret = __perf_read_group_add(leader, read_format, values);
4004 list_for_each_entry(child, &leader->child_list, child_list) {
4005 ret = __perf_read_group_add(child, read_format, values);
4010 mutex_unlock(&leader->child_mutex);
4012 ret = event->read_size;
4013 if (copy_to_user(buf, values, event->read_size))
4018 mutex_unlock(&leader->child_mutex);
4024 static int perf_read_one(struct perf_event *event,
4025 u64 read_format, char __user *buf)
4027 u64 enabled, running;
4031 values[n++] = perf_event_read_value(event, &enabled, &running);
4032 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4033 values[n++] = enabled;
4034 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4035 values[n++] = running;
4036 if (read_format & PERF_FORMAT_ID)
4037 values[n++] = primary_event_id(event);
4039 if (copy_to_user(buf, values, n * sizeof(u64)))
4042 return n * sizeof(u64);
4045 static bool is_event_hup(struct perf_event *event)
4049 if (event->state != PERF_EVENT_STATE_EXIT)
4052 mutex_lock(&event->child_mutex);
4053 no_children = list_empty(&event->child_list);
4054 mutex_unlock(&event->child_mutex);
4059 * Read the performance event - simple non blocking version for now
4062 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4064 u64 read_format = event->attr.read_format;
4068 * Return end-of-file for a read on a event that is in
4069 * error state (i.e. because it was pinned but it couldn't be
4070 * scheduled on to the CPU at some point).
4072 if (event->state == PERF_EVENT_STATE_ERROR)
4075 if (count < event->read_size)
4078 WARN_ON_ONCE(event->ctx->parent_ctx);
4079 if (read_format & PERF_FORMAT_GROUP)
4080 ret = perf_read_group(event, read_format, buf);
4082 ret = perf_read_one(event, read_format, buf);
4088 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4090 struct perf_event *event = file->private_data;
4091 struct perf_event_context *ctx;
4094 ctx = perf_event_ctx_lock(event);
4095 ret = __perf_read(event, buf, count);
4096 perf_event_ctx_unlock(event, ctx);
4101 static unsigned int perf_poll(struct file *file, poll_table *wait)
4103 struct perf_event *event = file->private_data;
4104 struct ring_buffer *rb;
4105 unsigned int events = POLLHUP;
4107 poll_wait(file, &event->waitq, wait);
4109 if (is_event_hup(event))
4113 * Pin the event->rb by taking event->mmap_mutex; otherwise
4114 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4116 mutex_lock(&event->mmap_mutex);
4119 events = atomic_xchg(&rb->poll, 0);
4120 mutex_unlock(&event->mmap_mutex);
4124 static void _perf_event_reset(struct perf_event *event)
4126 (void)perf_event_read(event, false);
4127 local64_set(&event->count, 0);
4128 perf_event_update_userpage(event);
4132 * Holding the top-level event's child_mutex means that any
4133 * descendant process that has inherited this event will block
4134 * in sync_child_event if it goes to exit, thus satisfying the
4135 * task existence requirements of perf_event_enable/disable.
4137 static void perf_event_for_each_child(struct perf_event *event,
4138 void (*func)(struct perf_event *))
4140 struct perf_event *child;
4142 WARN_ON_ONCE(event->ctx->parent_ctx);
4144 mutex_lock(&event->child_mutex);
4146 list_for_each_entry(child, &event->child_list, child_list)
4148 mutex_unlock(&event->child_mutex);
4151 static void perf_event_for_each(struct perf_event *event,
4152 void (*func)(struct perf_event *))
4154 struct perf_event_context *ctx = event->ctx;
4155 struct perf_event *sibling;
4157 lockdep_assert_held(&ctx->mutex);
4159 event = event->group_leader;
4161 perf_event_for_each_child(event, func);
4162 list_for_each_entry(sibling, &event->sibling_list, group_entry)
4163 perf_event_for_each_child(sibling, func);
4166 struct period_event {
4167 struct perf_event *event;
4171 static int __perf_event_period(void *info)
4173 struct period_event *pe = info;
4174 struct perf_event *event = pe->event;
4175 struct perf_event_context *ctx = event->ctx;
4176 u64 value = pe->value;
4179 raw_spin_lock(&ctx->lock);
4180 if (event->attr.freq) {
4181 event->attr.sample_freq = value;
4183 event->attr.sample_period = value;
4184 event->hw.sample_period = value;
4187 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4189 perf_pmu_disable(ctx->pmu);
4190 event->pmu->stop(event, PERF_EF_UPDATE);
4193 local64_set(&event->hw.period_left, 0);
4196 event->pmu->start(event, PERF_EF_RELOAD);
4197 perf_pmu_enable(ctx->pmu);
4199 raw_spin_unlock(&ctx->lock);
4204 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4206 struct period_event pe = { .event = event, };
4207 struct perf_event_context *ctx = event->ctx;
4208 struct task_struct *task;
4211 if (!is_sampling_event(event))
4214 if (copy_from_user(&value, arg, sizeof(value)))
4220 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4227 cpu_function_call(event->cpu, __perf_event_period, &pe);
4232 if (!task_function_call(task, __perf_event_period, &pe))
4235 raw_spin_lock_irq(&ctx->lock);
4236 if (ctx->is_active) {
4237 raw_spin_unlock_irq(&ctx->lock);
4242 if (event->attr.freq) {
4243 event->attr.sample_freq = value;
4245 event->attr.sample_period = value;
4246 event->hw.sample_period = value;
4249 local64_set(&event->hw.period_left, 0);
4250 raw_spin_unlock_irq(&ctx->lock);
4255 static const struct file_operations perf_fops;
4257 static inline int perf_fget_light(int fd, struct fd *p)
4259 struct fd f = fdget(fd);
4263 if (f.file->f_op != &perf_fops) {
4271 static int perf_event_set_output(struct perf_event *event,
4272 struct perf_event *output_event);
4273 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
4274 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
4276 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
4278 void (*func)(struct perf_event *);
4282 case PERF_EVENT_IOC_ENABLE:
4283 func = _perf_event_enable;
4285 case PERF_EVENT_IOC_DISABLE:
4286 func = _perf_event_disable;
4288 case PERF_EVENT_IOC_RESET:
4289 func = _perf_event_reset;
4292 case PERF_EVENT_IOC_REFRESH:
4293 return _perf_event_refresh(event, arg);
4295 case PERF_EVENT_IOC_PERIOD:
4296 return perf_event_period(event, (u64 __user *)arg);
4298 case PERF_EVENT_IOC_ID:
4300 u64 id = primary_event_id(event);
4302 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
4307 case PERF_EVENT_IOC_SET_OUTPUT:
4311 struct perf_event *output_event;
4313 ret = perf_fget_light(arg, &output);
4316 output_event = output.file->private_data;
4317 ret = perf_event_set_output(event, output_event);
4320 ret = perf_event_set_output(event, NULL);
4325 case PERF_EVENT_IOC_SET_FILTER:
4326 return perf_event_set_filter(event, (void __user *)arg);
4328 case PERF_EVENT_IOC_SET_BPF:
4329 return perf_event_set_bpf_prog(event, arg);
4335 if (flags & PERF_IOC_FLAG_GROUP)
4336 perf_event_for_each(event, func);
4338 perf_event_for_each_child(event, func);
4343 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
4345 struct perf_event *event = file->private_data;
4346 struct perf_event_context *ctx;
4349 ctx = perf_event_ctx_lock(event);
4350 ret = _perf_ioctl(event, cmd, arg);
4351 perf_event_ctx_unlock(event, ctx);
4356 #ifdef CONFIG_COMPAT
4357 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
4360 switch (_IOC_NR(cmd)) {
4361 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
4362 case _IOC_NR(PERF_EVENT_IOC_ID):
4363 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
4364 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
4365 cmd &= ~IOCSIZE_MASK;
4366 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
4370 return perf_ioctl(file, cmd, arg);
4373 # define perf_compat_ioctl NULL
4376 int perf_event_task_enable(void)
4378 struct perf_event_context *ctx;
4379 struct perf_event *event;
4381 mutex_lock(¤t->perf_event_mutex);
4382 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4383 ctx = perf_event_ctx_lock(event);
4384 perf_event_for_each_child(event, _perf_event_enable);
4385 perf_event_ctx_unlock(event, ctx);
4387 mutex_unlock(¤t->perf_event_mutex);
4392 int perf_event_task_disable(void)
4394 struct perf_event_context *ctx;
4395 struct perf_event *event;
4397 mutex_lock(¤t->perf_event_mutex);
4398 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
4399 ctx = perf_event_ctx_lock(event);
4400 perf_event_for_each_child(event, _perf_event_disable);
4401 perf_event_ctx_unlock(event, ctx);
4403 mutex_unlock(¤t->perf_event_mutex);
4408 static int perf_event_index(struct perf_event *event)
4410 if (event->hw.state & PERF_HES_STOPPED)
4413 if (event->state != PERF_EVENT_STATE_ACTIVE)
4416 return event->pmu->event_idx(event);
4419 static void calc_timer_values(struct perf_event *event,
4426 *now = perf_clock();
4427 ctx_time = event->shadow_ctx_time + *now;
4428 *enabled = ctx_time - event->tstamp_enabled;
4429 *running = ctx_time - event->tstamp_running;
4432 static void perf_event_init_userpage(struct perf_event *event)
4434 struct perf_event_mmap_page *userpg;
4435 struct ring_buffer *rb;
4438 rb = rcu_dereference(event->rb);
4442 userpg = rb->user_page;
4444 /* Allow new userspace to detect that bit 0 is deprecated */
4445 userpg->cap_bit0_is_deprecated = 1;
4446 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
4447 userpg->data_offset = PAGE_SIZE;
4448 userpg->data_size = perf_data_size(rb);
4454 void __weak arch_perf_update_userpage(
4455 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
4460 * Callers need to ensure there can be no nesting of this function, otherwise
4461 * the seqlock logic goes bad. We can not serialize this because the arch
4462 * code calls this from NMI context.
4464 void perf_event_update_userpage(struct perf_event *event)
4466 struct perf_event_mmap_page *userpg;
4467 struct ring_buffer *rb;
4468 u64 enabled, running, now;
4471 rb = rcu_dereference(event->rb);
4476 * compute total_time_enabled, total_time_running
4477 * based on snapshot values taken when the event
4478 * was last scheduled in.
4480 * we cannot simply called update_context_time()
4481 * because of locking issue as we can be called in
4484 calc_timer_values(event, &now, &enabled, &running);
4486 userpg = rb->user_page;
4488 * Disable preemption so as to not let the corresponding user-space
4489 * spin too long if we get preempted.
4494 userpg->index = perf_event_index(event);
4495 userpg->offset = perf_event_count(event);
4497 userpg->offset -= local64_read(&event->hw.prev_count);
4499 userpg->time_enabled = enabled +
4500 atomic64_read(&event->child_total_time_enabled);
4502 userpg->time_running = running +
4503 atomic64_read(&event->child_total_time_running);
4505 arch_perf_update_userpage(event, userpg, now);
4514 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
4516 struct perf_event *event = vma->vm_file->private_data;
4517 struct ring_buffer *rb;
4518 int ret = VM_FAULT_SIGBUS;
4520 if (vmf->flags & FAULT_FLAG_MKWRITE) {
4521 if (vmf->pgoff == 0)
4527 rb = rcu_dereference(event->rb);
4531 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
4534 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
4538 get_page(vmf->page);
4539 vmf->page->mapping = vma->vm_file->f_mapping;
4540 vmf->page->index = vmf->pgoff;
4549 static void ring_buffer_attach(struct perf_event *event,
4550 struct ring_buffer *rb)
4552 struct ring_buffer *old_rb = NULL;
4553 unsigned long flags;
4557 * Should be impossible, we set this when removing
4558 * event->rb_entry and wait/clear when adding event->rb_entry.
4560 WARN_ON_ONCE(event->rcu_pending);
4563 spin_lock_irqsave(&old_rb->event_lock, flags);
4564 list_del_rcu(&event->rb_entry);
4565 spin_unlock_irqrestore(&old_rb->event_lock, flags);
4567 event->rcu_batches = get_state_synchronize_rcu();
4568 event->rcu_pending = 1;
4572 if (event->rcu_pending) {
4573 cond_synchronize_rcu(event->rcu_batches);
4574 event->rcu_pending = 0;
4577 spin_lock_irqsave(&rb->event_lock, flags);
4578 list_add_rcu(&event->rb_entry, &rb->event_list);
4579 spin_unlock_irqrestore(&rb->event_lock, flags);
4582 rcu_assign_pointer(event->rb, rb);
4585 ring_buffer_put(old_rb);
4587 * Since we detached before setting the new rb, so that we
4588 * could attach the new rb, we could have missed a wakeup.
4591 wake_up_all(&event->waitq);
4595 static void ring_buffer_wakeup(struct perf_event *event)
4597 struct ring_buffer *rb;
4600 rb = rcu_dereference(event->rb);
4602 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
4603 wake_up_all(&event->waitq);
4608 struct ring_buffer *ring_buffer_get(struct perf_event *event)
4610 struct ring_buffer *rb;
4613 rb = rcu_dereference(event->rb);
4615 if (!atomic_inc_not_zero(&rb->refcount))
4623 void ring_buffer_put(struct ring_buffer *rb)
4625 if (!atomic_dec_and_test(&rb->refcount))
4628 WARN_ON_ONCE(!list_empty(&rb->event_list));
4630 call_rcu(&rb->rcu_head, rb_free_rcu);
4633 static void perf_mmap_open(struct vm_area_struct *vma)
4635 struct perf_event *event = vma->vm_file->private_data;
4637 atomic_inc(&event->mmap_count);
4638 atomic_inc(&event->rb->mmap_count);
4641 atomic_inc(&event->rb->aux_mmap_count);
4643 if (event->pmu->event_mapped)
4644 event->pmu->event_mapped(event);
4647 static void perf_pmu_output_stop(struct perf_event *event);
4650 * A buffer can be mmap()ed multiple times; either directly through the same
4651 * event, or through other events by use of perf_event_set_output().
4653 * In order to undo the VM accounting done by perf_mmap() we need to destroy
4654 * the buffer here, where we still have a VM context. This means we need
4655 * to detach all events redirecting to us.
4657 static void perf_mmap_close(struct vm_area_struct *vma)
4659 struct perf_event *event = vma->vm_file->private_data;
4661 struct ring_buffer *rb = ring_buffer_get(event);
4662 struct user_struct *mmap_user = rb->mmap_user;
4663 int mmap_locked = rb->mmap_locked;
4664 unsigned long size = perf_data_size(rb);
4666 if (event->pmu->event_unmapped)
4667 event->pmu->event_unmapped(event);
4670 * rb->aux_mmap_count will always drop before rb->mmap_count and
4671 * event->mmap_count, so it is ok to use event->mmap_mutex to
4672 * serialize with perf_mmap here.
4674 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
4675 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
4677 * Stop all AUX events that are writing to this buffer,
4678 * so that we can free its AUX pages and corresponding PMU
4679 * data. Note that after rb::aux_mmap_count dropped to zero,
4680 * they won't start any more (see perf_aux_output_begin()).
4682 perf_pmu_output_stop(event);
4684 /* now it's safe to free the pages */
4685 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
4686 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
4688 /* this has to be the last one */
4690 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
4692 mutex_unlock(&event->mmap_mutex);
4695 atomic_dec(&rb->mmap_count);
4697 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
4700 ring_buffer_attach(event, NULL);
4701 mutex_unlock(&event->mmap_mutex);
4703 /* If there's still other mmap()s of this buffer, we're done. */
4704 if (atomic_read(&rb->mmap_count))
4708 * No other mmap()s, detach from all other events that might redirect
4709 * into the now unreachable buffer. Somewhat complicated by the
4710 * fact that rb::event_lock otherwise nests inside mmap_mutex.
4714 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
4715 if (!atomic_long_inc_not_zero(&event->refcount)) {
4717 * This event is en-route to free_event() which will
4718 * detach it and remove it from the list.
4724 mutex_lock(&event->mmap_mutex);
4726 * Check we didn't race with perf_event_set_output() which can
4727 * swizzle the rb from under us while we were waiting to
4728 * acquire mmap_mutex.
4730 * If we find a different rb; ignore this event, a next
4731 * iteration will no longer find it on the list. We have to
4732 * still restart the iteration to make sure we're not now
4733 * iterating the wrong list.
4735 if (event->rb == rb)
4736 ring_buffer_attach(event, NULL);
4738 mutex_unlock(&event->mmap_mutex);
4742 * Restart the iteration; either we're on the wrong list or
4743 * destroyed its integrity by doing a deletion.
4750 * It could be there's still a few 0-ref events on the list; they'll
4751 * get cleaned up by free_event() -- they'll also still have their
4752 * ref on the rb and will free it whenever they are done with it.
4754 * Aside from that, this buffer is 'fully' detached and unmapped,
4755 * undo the VM accounting.
4758 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
4759 vma->vm_mm->pinned_vm -= mmap_locked;
4760 free_uid(mmap_user);
4763 ring_buffer_put(rb); /* could be last */
4766 static const struct vm_operations_struct perf_mmap_vmops = {
4767 .open = perf_mmap_open,
4768 .close = perf_mmap_close, /* non mergable */
4769 .fault = perf_mmap_fault,
4770 .page_mkwrite = perf_mmap_fault,
4773 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
4775 struct perf_event *event = file->private_data;
4776 unsigned long user_locked, user_lock_limit;
4777 struct user_struct *user = current_user();
4778 unsigned long locked, lock_limit;
4779 struct ring_buffer *rb = NULL;
4780 unsigned long vma_size;
4781 unsigned long nr_pages;
4782 long user_extra = 0, extra = 0;
4783 int ret = 0, flags = 0;
4786 * Don't allow mmap() of inherited per-task counters. This would
4787 * create a performance issue due to all children writing to the
4790 if (event->cpu == -1 && event->attr.inherit)
4793 if (!(vma->vm_flags & VM_SHARED))
4796 vma_size = vma->vm_end - vma->vm_start;
4798 if (vma->vm_pgoff == 0) {
4799 nr_pages = (vma_size / PAGE_SIZE) - 1;
4802 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
4803 * mapped, all subsequent mappings should have the same size
4804 * and offset. Must be above the normal perf buffer.
4806 u64 aux_offset, aux_size;
4811 nr_pages = vma_size / PAGE_SIZE;
4813 mutex_lock(&event->mmap_mutex);
4820 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset);
4821 aux_size = ACCESS_ONCE(rb->user_page->aux_size);
4823 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
4826 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
4829 /* already mapped with a different offset */
4830 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
4833 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
4836 /* already mapped with a different size */
4837 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
4840 if (!is_power_of_2(nr_pages))
4843 if (!atomic_inc_not_zero(&rb->mmap_count))
4846 if (rb_has_aux(rb)) {
4847 atomic_inc(&rb->aux_mmap_count);
4852 atomic_set(&rb->aux_mmap_count, 1);
4853 user_extra = nr_pages;
4859 * If we have rb pages ensure they're a power-of-two number, so we
4860 * can do bitmasks instead of modulo.
4862 if (nr_pages != 0 && !is_power_of_2(nr_pages))
4865 if (vma_size != PAGE_SIZE * (1 + nr_pages))
4868 WARN_ON_ONCE(event->ctx->parent_ctx);
4870 mutex_lock(&event->mmap_mutex);
4872 if (event->rb->nr_pages != nr_pages) {
4877 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
4879 * Raced against perf_mmap_close() through
4880 * perf_event_set_output(). Try again, hope for better
4883 mutex_unlock(&event->mmap_mutex);
4890 user_extra = nr_pages + 1;
4893 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
4896 * Increase the limit linearly with more CPUs:
4898 user_lock_limit *= num_online_cpus();
4900 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
4902 if (user_locked > user_lock_limit)
4903 extra = user_locked - user_lock_limit;
4905 lock_limit = rlimit(RLIMIT_MEMLOCK);
4906 lock_limit >>= PAGE_SHIFT;
4907 locked = vma->vm_mm->pinned_vm + extra;
4909 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
4910 !capable(CAP_IPC_LOCK)) {
4915 WARN_ON(!rb && event->rb);
4917 if (vma->vm_flags & VM_WRITE)
4918 flags |= RING_BUFFER_WRITABLE;
4921 rb = rb_alloc(nr_pages,
4922 event->attr.watermark ? event->attr.wakeup_watermark : 0,
4930 atomic_set(&rb->mmap_count, 1);
4931 rb->mmap_user = get_current_user();
4932 rb->mmap_locked = extra;
4934 ring_buffer_attach(event, rb);
4936 perf_event_init_userpage(event);
4937 perf_event_update_userpage(event);
4939 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
4940 event->attr.aux_watermark, flags);
4942 rb->aux_mmap_locked = extra;
4947 atomic_long_add(user_extra, &user->locked_vm);
4948 vma->vm_mm->pinned_vm += extra;
4950 atomic_inc(&event->mmap_count);
4952 atomic_dec(&rb->mmap_count);
4955 mutex_unlock(&event->mmap_mutex);
4958 * Since pinned accounting is per vm we cannot allow fork() to copy our
4961 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4962 vma->vm_ops = &perf_mmap_vmops;
4964 if (event->pmu->event_mapped)
4965 event->pmu->event_mapped(event);
4970 static int perf_fasync(int fd, struct file *filp, int on)
4972 struct inode *inode = file_inode(filp);
4973 struct perf_event *event = filp->private_data;
4976 mutex_lock(&inode->i_mutex);
4977 retval = fasync_helper(fd, filp, on, &event->fasync);
4978 mutex_unlock(&inode->i_mutex);
4986 static const struct file_operations perf_fops = {
4987 .llseek = no_llseek,
4988 .release = perf_release,
4991 .unlocked_ioctl = perf_ioctl,
4992 .compat_ioctl = perf_compat_ioctl,
4994 .fasync = perf_fasync,
5000 * If there's data, ensure we set the poll() state and publish everything
5001 * to user-space before waking everybody up.
5004 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5006 /* only the parent has fasync state */
5008 event = event->parent;
5009 return &event->fasync;
5012 void perf_event_wakeup(struct perf_event *event)
5014 ring_buffer_wakeup(event);
5016 if (event->pending_kill) {
5017 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5018 event->pending_kill = 0;
5022 static void perf_pending_event(struct irq_work *entry)
5024 struct perf_event *event = container_of(entry,
5025 struct perf_event, pending);
5028 rctx = perf_swevent_get_recursion_context();
5030 * If we 'fail' here, that's OK, it means recursion is already disabled
5031 * and we won't recurse 'further'.
5034 if (event->pending_disable) {
5035 event->pending_disable = 0;
5036 __perf_event_disable(event);
5039 if (event->pending_wakeup) {
5040 event->pending_wakeup = 0;
5041 perf_event_wakeup(event);
5045 perf_swevent_put_recursion_context(rctx);
5049 * We assume there is only KVM supporting the callbacks.
5050 * Later on, we might change it to a list if there is
5051 * another virtualization implementation supporting the callbacks.
5053 struct perf_guest_info_callbacks *perf_guest_cbs;
5055 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5057 perf_guest_cbs = cbs;
5060 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5062 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5064 perf_guest_cbs = NULL;
5067 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5070 perf_output_sample_regs(struct perf_output_handle *handle,
5071 struct pt_regs *regs, u64 mask)
5075 for_each_set_bit(bit, (const unsigned long *) &mask,
5076 sizeof(mask) * BITS_PER_BYTE) {
5079 val = perf_reg_value(regs, bit);
5080 perf_output_put(handle, val);
5084 static void perf_sample_regs_user(struct perf_regs *regs_user,
5085 struct pt_regs *regs,
5086 struct pt_regs *regs_user_copy)
5088 if (user_mode(regs)) {
5089 regs_user->abi = perf_reg_abi(current);
5090 regs_user->regs = regs;
5091 } else if (current->mm) {
5092 perf_get_regs_user(regs_user, regs, regs_user_copy);
5094 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5095 regs_user->regs = NULL;
5099 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5100 struct pt_regs *regs)
5102 regs_intr->regs = regs;
5103 regs_intr->abi = perf_reg_abi(current);
5108 * Get remaining task size from user stack pointer.
5110 * It'd be better to take stack vma map and limit this more
5111 * precisly, but there's no way to get it safely under interrupt,
5112 * so using TASK_SIZE as limit.
5114 static u64 perf_ustack_task_size(struct pt_regs *regs)
5116 unsigned long addr = perf_user_stack_pointer(regs);
5118 if (!addr || addr >= TASK_SIZE)
5121 return TASK_SIZE - addr;
5125 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5126 struct pt_regs *regs)
5130 /* No regs, no stack pointer, no dump. */
5135 * Check if we fit in with the requested stack size into the:
5137 * If we don't, we limit the size to the TASK_SIZE.
5139 * - remaining sample size
5140 * If we don't, we customize the stack size to
5141 * fit in to the remaining sample size.
5144 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5145 stack_size = min(stack_size, (u16) task_size);
5147 /* Current header size plus static size and dynamic size. */
5148 header_size += 2 * sizeof(u64);
5150 /* Do we fit in with the current stack dump size? */
5151 if ((u16) (header_size + stack_size) < header_size) {
5153 * If we overflow the maximum size for the sample,
5154 * we customize the stack dump size to fit in.
5156 stack_size = USHRT_MAX - header_size - sizeof(u64);
5157 stack_size = round_up(stack_size, sizeof(u64));
5164 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5165 struct pt_regs *regs)
5167 /* Case of a kernel thread, nothing to dump */
5170 perf_output_put(handle, size);
5179 * - the size requested by user or the best one we can fit
5180 * in to the sample max size
5182 * - user stack dump data
5184 * - the actual dumped size
5188 perf_output_put(handle, dump_size);
5191 sp = perf_user_stack_pointer(regs);
5192 rem = __output_copy_user(handle, (void *) sp, dump_size);
5193 dyn_size = dump_size - rem;
5195 perf_output_skip(handle, rem);
5198 perf_output_put(handle, dyn_size);
5202 static void __perf_event_header__init_id(struct perf_event_header *header,
5203 struct perf_sample_data *data,
5204 struct perf_event *event)
5206 u64 sample_type = event->attr.sample_type;
5208 data->type = sample_type;
5209 header->size += event->id_header_size;
5211 if (sample_type & PERF_SAMPLE_TID) {
5212 /* namespace issues */
5213 data->tid_entry.pid = perf_event_pid(event, current);
5214 data->tid_entry.tid = perf_event_tid(event, current);
5217 if (sample_type & PERF_SAMPLE_TIME)
5218 data->time = perf_event_clock(event);
5220 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
5221 data->id = primary_event_id(event);
5223 if (sample_type & PERF_SAMPLE_STREAM_ID)
5224 data->stream_id = event->id;
5226 if (sample_type & PERF_SAMPLE_CPU) {
5227 data->cpu_entry.cpu = raw_smp_processor_id();
5228 data->cpu_entry.reserved = 0;
5232 void perf_event_header__init_id(struct perf_event_header *header,
5233 struct perf_sample_data *data,
5234 struct perf_event *event)
5236 if (event->attr.sample_id_all)
5237 __perf_event_header__init_id(header, data, event);
5240 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
5241 struct perf_sample_data *data)
5243 u64 sample_type = data->type;
5245 if (sample_type & PERF_SAMPLE_TID)
5246 perf_output_put(handle, data->tid_entry);
5248 if (sample_type & PERF_SAMPLE_TIME)
5249 perf_output_put(handle, data->time);
5251 if (sample_type & PERF_SAMPLE_ID)
5252 perf_output_put(handle, data->id);
5254 if (sample_type & PERF_SAMPLE_STREAM_ID)
5255 perf_output_put(handle, data->stream_id);
5257 if (sample_type & PERF_SAMPLE_CPU)
5258 perf_output_put(handle, data->cpu_entry);
5260 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5261 perf_output_put(handle, data->id);
5264 void perf_event__output_id_sample(struct perf_event *event,
5265 struct perf_output_handle *handle,
5266 struct perf_sample_data *sample)
5268 if (event->attr.sample_id_all)
5269 __perf_event__output_id_sample(handle, sample);
5272 static void perf_output_read_one(struct perf_output_handle *handle,
5273 struct perf_event *event,
5274 u64 enabled, u64 running)
5276 u64 read_format = event->attr.read_format;
5280 values[n++] = perf_event_count(event);
5281 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5282 values[n++] = enabled +
5283 atomic64_read(&event->child_total_time_enabled);
5285 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5286 values[n++] = running +
5287 atomic64_read(&event->child_total_time_running);
5289 if (read_format & PERF_FORMAT_ID)
5290 values[n++] = primary_event_id(event);
5292 __output_copy(handle, values, n * sizeof(u64));
5296 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
5298 static void perf_output_read_group(struct perf_output_handle *handle,
5299 struct perf_event *event,
5300 u64 enabled, u64 running)
5302 struct perf_event *leader = event->group_leader, *sub;
5303 u64 read_format = event->attr.read_format;
5307 values[n++] = 1 + leader->nr_siblings;
5309 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5310 values[n++] = enabled;
5312 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5313 values[n++] = running;
5315 if (leader != event)
5316 leader->pmu->read(leader);
5318 values[n++] = perf_event_count(leader);
5319 if (read_format & PERF_FORMAT_ID)
5320 values[n++] = primary_event_id(leader);
5322 __output_copy(handle, values, n * sizeof(u64));
5324 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
5327 if ((sub != event) &&
5328 (sub->state == PERF_EVENT_STATE_ACTIVE))
5329 sub->pmu->read(sub);
5331 values[n++] = perf_event_count(sub);
5332 if (read_format & PERF_FORMAT_ID)
5333 values[n++] = primary_event_id(sub);
5335 __output_copy(handle, values, n * sizeof(u64));
5339 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
5340 PERF_FORMAT_TOTAL_TIME_RUNNING)
5342 static void perf_output_read(struct perf_output_handle *handle,
5343 struct perf_event *event)
5345 u64 enabled = 0, running = 0, now;
5346 u64 read_format = event->attr.read_format;
5349 * compute total_time_enabled, total_time_running
5350 * based on snapshot values taken when the event
5351 * was last scheduled in.
5353 * we cannot simply called update_context_time()
5354 * because of locking issue as we are called in
5357 if (read_format & PERF_FORMAT_TOTAL_TIMES)
5358 calc_timer_values(event, &now, &enabled, &running);
5360 if (event->attr.read_format & PERF_FORMAT_GROUP)
5361 perf_output_read_group(handle, event, enabled, running);
5363 perf_output_read_one(handle, event, enabled, running);
5366 void perf_output_sample(struct perf_output_handle *handle,
5367 struct perf_event_header *header,
5368 struct perf_sample_data *data,
5369 struct perf_event *event)
5371 u64 sample_type = data->type;
5373 perf_output_put(handle, *header);
5375 if (sample_type & PERF_SAMPLE_IDENTIFIER)
5376 perf_output_put(handle, data->id);
5378 if (sample_type & PERF_SAMPLE_IP)
5379 perf_output_put(handle, data->ip);
5381 if (sample_type & PERF_SAMPLE_TID)
5382 perf_output_put(handle, data->tid_entry);
5384 if (sample_type & PERF_SAMPLE_TIME)
5385 perf_output_put(handle, data->time);
5387 if (sample_type & PERF_SAMPLE_ADDR)
5388 perf_output_put(handle, data->addr);
5390 if (sample_type & PERF_SAMPLE_ID)
5391 perf_output_put(handle, data->id);
5393 if (sample_type & PERF_SAMPLE_STREAM_ID)
5394 perf_output_put(handle, data->stream_id);
5396 if (sample_type & PERF_SAMPLE_CPU)
5397 perf_output_put(handle, data->cpu_entry);
5399 if (sample_type & PERF_SAMPLE_PERIOD)
5400 perf_output_put(handle, data->period);
5402 if (sample_type & PERF_SAMPLE_READ)
5403 perf_output_read(handle, event);
5405 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5406 if (data->callchain) {
5409 if (data->callchain)
5410 size += data->callchain->nr;
5412 size *= sizeof(u64);
5414 __output_copy(handle, data->callchain, size);
5417 perf_output_put(handle, nr);
5421 if (sample_type & PERF_SAMPLE_RAW) {
5423 u32 raw_size = data->raw->size;
5424 u32 real_size = round_up(raw_size + sizeof(u32),
5425 sizeof(u64)) - sizeof(u32);
5428 perf_output_put(handle, real_size);
5429 __output_copy(handle, data->raw->data, raw_size);
5430 if (real_size - raw_size)
5431 __output_copy(handle, &zero, real_size - raw_size);
5437 .size = sizeof(u32),
5440 perf_output_put(handle, raw);
5444 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5445 if (data->br_stack) {
5448 size = data->br_stack->nr
5449 * sizeof(struct perf_branch_entry);
5451 perf_output_put(handle, data->br_stack->nr);
5452 perf_output_copy(handle, data->br_stack->entries, size);
5455 * we always store at least the value of nr
5458 perf_output_put(handle, nr);
5462 if (sample_type & PERF_SAMPLE_REGS_USER) {
5463 u64 abi = data->regs_user.abi;
5466 * If there are no regs to dump, notice it through
5467 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5469 perf_output_put(handle, abi);
5472 u64 mask = event->attr.sample_regs_user;
5473 perf_output_sample_regs(handle,
5474 data->regs_user.regs,
5479 if (sample_type & PERF_SAMPLE_STACK_USER) {
5480 perf_output_sample_ustack(handle,
5481 data->stack_user_size,
5482 data->regs_user.regs);
5485 if (sample_type & PERF_SAMPLE_WEIGHT)
5486 perf_output_put(handle, data->weight);
5488 if (sample_type & PERF_SAMPLE_DATA_SRC)
5489 perf_output_put(handle, data->data_src.val);
5491 if (sample_type & PERF_SAMPLE_TRANSACTION)
5492 perf_output_put(handle, data->txn);
5494 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5495 u64 abi = data->regs_intr.abi;
5497 * If there are no regs to dump, notice it through
5498 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
5500 perf_output_put(handle, abi);
5503 u64 mask = event->attr.sample_regs_intr;
5505 perf_output_sample_regs(handle,
5506 data->regs_intr.regs,
5511 if (!event->attr.watermark) {
5512 int wakeup_events = event->attr.wakeup_events;
5514 if (wakeup_events) {
5515 struct ring_buffer *rb = handle->rb;
5516 int events = local_inc_return(&rb->events);
5518 if (events >= wakeup_events) {
5519 local_sub(wakeup_events, &rb->events);
5520 local_inc(&rb->wakeup);
5526 void perf_prepare_sample(struct perf_event_header *header,
5527 struct perf_sample_data *data,
5528 struct perf_event *event,
5529 struct pt_regs *regs)
5531 u64 sample_type = event->attr.sample_type;
5533 header->type = PERF_RECORD_SAMPLE;
5534 header->size = sizeof(*header) + event->header_size;
5537 header->misc |= perf_misc_flags(regs);
5539 __perf_event_header__init_id(header, data, event);
5541 if (sample_type & PERF_SAMPLE_IP)
5542 data->ip = perf_instruction_pointer(regs);
5544 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
5547 data->callchain = perf_callchain(event, regs);
5549 if (data->callchain)
5550 size += data->callchain->nr;
5552 header->size += size * sizeof(u64);
5555 if (sample_type & PERF_SAMPLE_RAW) {
5556 int size = sizeof(u32);
5559 size += data->raw->size;
5561 size += sizeof(u32);
5563 header->size += round_up(size, sizeof(u64));
5566 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
5567 int size = sizeof(u64); /* nr */
5568 if (data->br_stack) {
5569 size += data->br_stack->nr
5570 * sizeof(struct perf_branch_entry);
5572 header->size += size;
5575 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
5576 perf_sample_regs_user(&data->regs_user, regs,
5577 &data->regs_user_copy);
5579 if (sample_type & PERF_SAMPLE_REGS_USER) {
5580 /* regs dump ABI info */
5581 int size = sizeof(u64);
5583 if (data->regs_user.regs) {
5584 u64 mask = event->attr.sample_regs_user;
5585 size += hweight64(mask) * sizeof(u64);
5588 header->size += size;
5591 if (sample_type & PERF_SAMPLE_STACK_USER) {
5593 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
5594 * processed as the last one or have additional check added
5595 * in case new sample type is added, because we could eat
5596 * up the rest of the sample size.
5598 u16 stack_size = event->attr.sample_stack_user;
5599 u16 size = sizeof(u64);
5601 stack_size = perf_sample_ustack_size(stack_size, header->size,
5602 data->regs_user.regs);
5605 * If there is something to dump, add space for the dump
5606 * itself and for the field that tells the dynamic size,
5607 * which is how many have been actually dumped.
5610 size += sizeof(u64) + stack_size;
5612 data->stack_user_size = stack_size;
5613 header->size += size;
5616 if (sample_type & PERF_SAMPLE_REGS_INTR) {
5617 /* regs dump ABI info */
5618 int size = sizeof(u64);
5620 perf_sample_regs_intr(&data->regs_intr, regs);
5622 if (data->regs_intr.regs) {
5623 u64 mask = event->attr.sample_regs_intr;
5625 size += hweight64(mask) * sizeof(u64);
5628 header->size += size;
5632 void perf_event_output(struct perf_event *event,
5633 struct perf_sample_data *data,
5634 struct pt_regs *regs)
5636 struct perf_output_handle handle;
5637 struct perf_event_header header;
5639 /* protect the callchain buffers */
5642 perf_prepare_sample(&header, data, event, regs);
5644 if (perf_output_begin(&handle, event, header.size))
5647 perf_output_sample(&handle, &header, data, event);
5649 perf_output_end(&handle);
5659 struct perf_read_event {
5660 struct perf_event_header header;
5667 perf_event_read_event(struct perf_event *event,
5668 struct task_struct *task)
5670 struct perf_output_handle handle;
5671 struct perf_sample_data sample;
5672 struct perf_read_event read_event = {
5674 .type = PERF_RECORD_READ,
5676 .size = sizeof(read_event) + event->read_size,
5678 .pid = perf_event_pid(event, task),
5679 .tid = perf_event_tid(event, task),
5683 perf_event_header__init_id(&read_event.header, &sample, event);
5684 ret = perf_output_begin(&handle, event, read_event.header.size);
5688 perf_output_put(&handle, read_event);
5689 perf_output_read(&handle, event);
5690 perf_event__output_id_sample(event, &handle, &sample);
5692 perf_output_end(&handle);
5695 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
5698 perf_event_aux_ctx(struct perf_event_context *ctx,
5699 perf_event_aux_output_cb output,
5702 struct perf_event *event;
5704 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5705 if (event->state < PERF_EVENT_STATE_INACTIVE)
5707 if (!event_filter_match(event))
5709 output(event, data);
5714 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data,
5715 struct perf_event_context *task_ctx)
5719 perf_event_aux_ctx(task_ctx, output, data);
5725 perf_event_aux(perf_event_aux_output_cb output, void *data,
5726 struct perf_event_context *task_ctx)
5728 struct perf_cpu_context *cpuctx;
5729 struct perf_event_context *ctx;
5734 * If we have task_ctx != NULL we only notify
5735 * the task context itself. The task_ctx is set
5736 * only for EXIT events before releasing task
5740 perf_event_aux_task_ctx(output, data, task_ctx);
5745 list_for_each_entry_rcu(pmu, &pmus, entry) {
5746 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5747 if (cpuctx->unique_pmu != pmu)
5749 perf_event_aux_ctx(&cpuctx->ctx, output, data);
5750 ctxn = pmu->task_ctx_nr;
5753 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
5755 perf_event_aux_ctx(ctx, output, data);
5757 put_cpu_ptr(pmu->pmu_cpu_context);
5762 struct remote_output {
5763 struct ring_buffer *rb;
5767 static void __perf_event_output_stop(struct perf_event *event, void *data)
5769 struct perf_event *parent = event->parent;
5770 struct remote_output *ro = data;
5771 struct ring_buffer *rb = ro->rb;
5773 if (!has_aux(event))
5780 * In case of inheritance, it will be the parent that links to the
5781 * ring-buffer, but it will be the child that's actually using it:
5783 if (rcu_dereference(parent->rb) == rb)
5784 ro->err = __perf_event_stop(event);
5787 static int __perf_pmu_output_stop(void *info)
5789 struct perf_event *event = info;
5790 struct pmu *pmu = event->pmu;
5791 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
5792 struct remote_output ro = {
5797 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro);
5798 if (cpuctx->task_ctx)
5799 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop,
5806 static void perf_pmu_output_stop(struct perf_event *event)
5808 struct perf_event *iter;
5813 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
5815 * For per-CPU events, we need to make sure that neither they
5816 * nor their children are running; for cpu==-1 events it's
5817 * sufficient to stop the event itself if it's active, since
5818 * it can't have children.
5822 cpu = READ_ONCE(iter->oncpu);
5827 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
5828 if (err == -EAGAIN) {
5837 * task tracking -- fork/exit
5839 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
5842 struct perf_task_event {
5843 struct task_struct *task;
5844 struct perf_event_context *task_ctx;
5847 struct perf_event_header header;
5857 static int perf_event_task_match(struct perf_event *event)
5859 return event->attr.comm || event->attr.mmap ||
5860 event->attr.mmap2 || event->attr.mmap_data ||
5864 static void perf_event_task_output(struct perf_event *event,
5867 struct perf_task_event *task_event = data;
5868 struct perf_output_handle handle;
5869 struct perf_sample_data sample;
5870 struct task_struct *task = task_event->task;
5871 int ret, size = task_event->event_id.header.size;
5873 if (!perf_event_task_match(event))
5876 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
5878 ret = perf_output_begin(&handle, event,
5879 task_event->event_id.header.size);
5883 task_event->event_id.pid = perf_event_pid(event, task);
5884 task_event->event_id.ppid = perf_event_pid(event, current);
5886 task_event->event_id.tid = perf_event_tid(event, task);
5887 task_event->event_id.ptid = perf_event_tid(event, current);
5889 task_event->event_id.time = perf_event_clock(event);
5891 perf_output_put(&handle, task_event->event_id);
5893 perf_event__output_id_sample(event, &handle, &sample);
5895 perf_output_end(&handle);
5897 task_event->event_id.header.size = size;
5900 static void perf_event_task(struct task_struct *task,
5901 struct perf_event_context *task_ctx,
5904 struct perf_task_event task_event;
5906 if (!atomic_read(&nr_comm_events) &&
5907 !atomic_read(&nr_mmap_events) &&
5908 !atomic_read(&nr_task_events))
5911 task_event = (struct perf_task_event){
5913 .task_ctx = task_ctx,
5916 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
5918 .size = sizeof(task_event.event_id),
5928 perf_event_aux(perf_event_task_output,
5933 void perf_event_fork(struct task_struct *task)
5935 perf_event_task(task, NULL, 1);
5942 struct perf_comm_event {
5943 struct task_struct *task;
5948 struct perf_event_header header;
5955 static int perf_event_comm_match(struct perf_event *event)
5957 return event->attr.comm;
5960 static void perf_event_comm_output(struct perf_event *event,
5963 struct perf_comm_event *comm_event = data;
5964 struct perf_output_handle handle;
5965 struct perf_sample_data sample;
5966 int size = comm_event->event_id.header.size;
5969 if (!perf_event_comm_match(event))
5972 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
5973 ret = perf_output_begin(&handle, event,
5974 comm_event->event_id.header.size);
5979 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
5980 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
5982 perf_output_put(&handle, comm_event->event_id);
5983 __output_copy(&handle, comm_event->comm,
5984 comm_event->comm_size);
5986 perf_event__output_id_sample(event, &handle, &sample);
5988 perf_output_end(&handle);
5990 comm_event->event_id.header.size = size;
5993 static void perf_event_comm_event(struct perf_comm_event *comm_event)
5995 char comm[TASK_COMM_LEN];
5998 memset(comm, 0, sizeof(comm));
5999 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6000 size = ALIGN(strlen(comm)+1, sizeof(u64));
6002 comm_event->comm = comm;
6003 comm_event->comm_size = size;
6005 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6007 perf_event_aux(perf_event_comm_output,
6012 void perf_event_comm(struct task_struct *task, bool exec)
6014 struct perf_comm_event comm_event;
6016 if (!atomic_read(&nr_comm_events))
6019 comm_event = (struct perf_comm_event){
6025 .type = PERF_RECORD_COMM,
6026 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
6034 perf_event_comm_event(&comm_event);
6041 struct perf_mmap_event {
6042 struct vm_area_struct *vma;
6044 const char *file_name;
6052 struct perf_event_header header;
6062 static int perf_event_mmap_match(struct perf_event *event,
6065 struct perf_mmap_event *mmap_event = data;
6066 struct vm_area_struct *vma = mmap_event->vma;
6067 int executable = vma->vm_flags & VM_EXEC;
6069 return (!executable && event->attr.mmap_data) ||
6070 (executable && (event->attr.mmap || event->attr.mmap2));
6073 static void perf_event_mmap_output(struct perf_event *event,
6076 struct perf_mmap_event *mmap_event = data;
6077 struct perf_output_handle handle;
6078 struct perf_sample_data sample;
6079 int size = mmap_event->event_id.header.size;
6082 if (!perf_event_mmap_match(event, data))
6085 if (event->attr.mmap2) {
6086 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
6087 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
6088 mmap_event->event_id.header.size += sizeof(mmap_event->min);
6089 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
6090 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
6091 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
6092 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
6095 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
6096 ret = perf_output_begin(&handle, event,
6097 mmap_event->event_id.header.size);
6101 mmap_event->event_id.pid = perf_event_pid(event, current);
6102 mmap_event->event_id.tid = perf_event_tid(event, current);
6104 perf_output_put(&handle, mmap_event->event_id);
6106 if (event->attr.mmap2) {
6107 perf_output_put(&handle, mmap_event->maj);
6108 perf_output_put(&handle, mmap_event->min);
6109 perf_output_put(&handle, mmap_event->ino);
6110 perf_output_put(&handle, mmap_event->ino_generation);
6111 perf_output_put(&handle, mmap_event->prot);
6112 perf_output_put(&handle, mmap_event->flags);
6115 __output_copy(&handle, mmap_event->file_name,
6116 mmap_event->file_size);
6118 perf_event__output_id_sample(event, &handle, &sample);
6120 perf_output_end(&handle);
6122 mmap_event->event_id.header.size = size;
6125 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
6127 struct vm_area_struct *vma = mmap_event->vma;
6128 struct file *file = vma->vm_file;
6129 int maj = 0, min = 0;
6130 u64 ino = 0, gen = 0;
6131 u32 prot = 0, flags = 0;
6138 struct inode *inode;
6141 buf = kmalloc(PATH_MAX, GFP_KERNEL);
6147 * d_path() works from the end of the rb backwards, so we
6148 * need to add enough zero bytes after the string to handle
6149 * the 64bit alignment we do later.
6151 name = file_path(file, buf, PATH_MAX - sizeof(u64));
6156 inode = file_inode(vma->vm_file);
6157 dev = inode->i_sb->s_dev;
6159 gen = inode->i_generation;
6163 if (vma->vm_flags & VM_READ)
6165 if (vma->vm_flags & VM_WRITE)
6167 if (vma->vm_flags & VM_EXEC)
6170 if (vma->vm_flags & VM_MAYSHARE)
6173 flags = MAP_PRIVATE;
6175 if (vma->vm_flags & VM_DENYWRITE)
6176 flags |= MAP_DENYWRITE;
6177 if (vma->vm_flags & VM_MAYEXEC)
6178 flags |= MAP_EXECUTABLE;
6179 if (vma->vm_flags & VM_LOCKED)
6180 flags |= MAP_LOCKED;
6181 if (vma->vm_flags & VM_HUGETLB)
6182 flags |= MAP_HUGETLB;
6186 if (vma->vm_ops && vma->vm_ops->name) {
6187 name = (char *) vma->vm_ops->name(vma);
6192 name = (char *)arch_vma_name(vma);
6196 if (vma->vm_start <= vma->vm_mm->start_brk &&
6197 vma->vm_end >= vma->vm_mm->brk) {
6201 if (vma->vm_start <= vma->vm_mm->start_stack &&
6202 vma->vm_end >= vma->vm_mm->start_stack) {
6212 strlcpy(tmp, name, sizeof(tmp));
6216 * Since our buffer works in 8 byte units we need to align our string
6217 * size to a multiple of 8. However, we must guarantee the tail end is
6218 * zero'd out to avoid leaking random bits to userspace.
6220 size = strlen(name)+1;
6221 while (!IS_ALIGNED(size, sizeof(u64)))
6222 name[size++] = '\0';
6224 mmap_event->file_name = name;
6225 mmap_event->file_size = size;
6226 mmap_event->maj = maj;
6227 mmap_event->min = min;
6228 mmap_event->ino = ino;
6229 mmap_event->ino_generation = gen;
6230 mmap_event->prot = prot;
6231 mmap_event->flags = flags;
6233 if (!(vma->vm_flags & VM_EXEC))
6234 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
6236 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
6238 perf_event_aux(perf_event_mmap_output,
6245 void perf_event_mmap(struct vm_area_struct *vma)
6247 struct perf_mmap_event mmap_event;
6249 if (!atomic_read(&nr_mmap_events))
6252 mmap_event = (struct perf_mmap_event){
6258 .type = PERF_RECORD_MMAP,
6259 .misc = PERF_RECORD_MISC_USER,
6264 .start = vma->vm_start,
6265 .len = vma->vm_end - vma->vm_start,
6266 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
6268 /* .maj (attr_mmap2 only) */
6269 /* .min (attr_mmap2 only) */
6270 /* .ino (attr_mmap2 only) */
6271 /* .ino_generation (attr_mmap2 only) */
6272 /* .prot (attr_mmap2 only) */
6273 /* .flags (attr_mmap2 only) */
6276 perf_event_mmap_event(&mmap_event);
6279 void perf_event_aux_event(struct perf_event *event, unsigned long head,
6280 unsigned long size, u64 flags)
6282 struct perf_output_handle handle;
6283 struct perf_sample_data sample;
6284 struct perf_aux_event {
6285 struct perf_event_header header;
6291 .type = PERF_RECORD_AUX,
6293 .size = sizeof(rec),
6301 perf_event_header__init_id(&rec.header, &sample, event);
6302 ret = perf_output_begin(&handle, event, rec.header.size);
6307 perf_output_put(&handle, rec);
6308 perf_event__output_id_sample(event, &handle, &sample);
6310 perf_output_end(&handle);
6314 * Lost/dropped samples logging
6316 void perf_log_lost_samples(struct perf_event *event, u64 lost)
6318 struct perf_output_handle handle;
6319 struct perf_sample_data sample;
6323 struct perf_event_header header;
6325 } lost_samples_event = {
6327 .type = PERF_RECORD_LOST_SAMPLES,
6329 .size = sizeof(lost_samples_event),
6334 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
6336 ret = perf_output_begin(&handle, event,
6337 lost_samples_event.header.size);
6341 perf_output_put(&handle, lost_samples_event);
6342 perf_event__output_id_sample(event, &handle, &sample);
6343 perf_output_end(&handle);
6347 * context_switch tracking
6350 struct perf_switch_event {
6351 struct task_struct *task;
6352 struct task_struct *next_prev;
6355 struct perf_event_header header;
6361 static int perf_event_switch_match(struct perf_event *event)
6363 return event->attr.context_switch;
6366 static void perf_event_switch_output(struct perf_event *event, void *data)
6368 struct perf_switch_event *se = data;
6369 struct perf_output_handle handle;
6370 struct perf_sample_data sample;
6373 if (!perf_event_switch_match(event))
6376 /* Only CPU-wide events are allowed to see next/prev pid/tid */
6377 if (event->ctx->task) {
6378 se->event_id.header.type = PERF_RECORD_SWITCH;
6379 se->event_id.header.size = sizeof(se->event_id.header);
6381 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
6382 se->event_id.header.size = sizeof(se->event_id);
6383 se->event_id.next_prev_pid =
6384 perf_event_pid(event, se->next_prev);
6385 se->event_id.next_prev_tid =
6386 perf_event_tid(event, se->next_prev);
6389 perf_event_header__init_id(&se->event_id.header, &sample, event);
6391 ret = perf_output_begin(&handle, event, se->event_id.header.size);
6395 if (event->ctx->task)
6396 perf_output_put(&handle, se->event_id.header);
6398 perf_output_put(&handle, se->event_id);
6400 perf_event__output_id_sample(event, &handle, &sample);
6402 perf_output_end(&handle);
6405 static void perf_event_switch(struct task_struct *task,
6406 struct task_struct *next_prev, bool sched_in)
6408 struct perf_switch_event switch_event;
6410 /* N.B. caller checks nr_switch_events != 0 */
6412 switch_event = (struct perf_switch_event){
6414 .next_prev = next_prev,
6418 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
6421 /* .next_prev_pid */
6422 /* .next_prev_tid */
6426 perf_event_aux(perf_event_switch_output,
6432 * IRQ throttle logging
6435 static void perf_log_throttle(struct perf_event *event, int enable)
6437 struct perf_output_handle handle;
6438 struct perf_sample_data sample;
6442 struct perf_event_header header;
6446 } throttle_event = {
6448 .type = PERF_RECORD_THROTTLE,
6450 .size = sizeof(throttle_event),
6452 .time = perf_event_clock(event),
6453 .id = primary_event_id(event),
6454 .stream_id = event->id,
6458 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
6460 perf_event_header__init_id(&throttle_event.header, &sample, event);
6462 ret = perf_output_begin(&handle, event,
6463 throttle_event.header.size);
6467 perf_output_put(&handle, throttle_event);
6468 perf_event__output_id_sample(event, &handle, &sample);
6469 perf_output_end(&handle);
6472 static void perf_log_itrace_start(struct perf_event *event)
6474 struct perf_output_handle handle;
6475 struct perf_sample_data sample;
6476 struct perf_aux_event {
6477 struct perf_event_header header;
6484 event = event->parent;
6486 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
6487 event->hw.itrace_started)
6490 rec.header.type = PERF_RECORD_ITRACE_START;
6491 rec.header.misc = 0;
6492 rec.header.size = sizeof(rec);
6493 rec.pid = perf_event_pid(event, current);
6494 rec.tid = perf_event_tid(event, current);
6496 perf_event_header__init_id(&rec.header, &sample, event);
6497 ret = perf_output_begin(&handle, event, rec.header.size);
6502 perf_output_put(&handle, rec);
6503 perf_event__output_id_sample(event, &handle, &sample);
6505 perf_output_end(&handle);
6509 * Generic event overflow handling, sampling.
6512 static int __perf_event_overflow(struct perf_event *event,
6513 int throttle, struct perf_sample_data *data,
6514 struct pt_regs *regs)
6516 int events = atomic_read(&event->event_limit);
6517 struct hw_perf_event *hwc = &event->hw;
6522 * Non-sampling counters might still use the PMI to fold short
6523 * hardware counters, ignore those.
6525 if (unlikely(!is_sampling_event(event)))
6528 seq = __this_cpu_read(perf_throttled_seq);
6529 if (seq != hwc->interrupts_seq) {
6530 hwc->interrupts_seq = seq;
6531 hwc->interrupts = 1;
6534 if (unlikely(throttle
6535 && hwc->interrupts >= max_samples_per_tick)) {
6536 __this_cpu_inc(perf_throttled_count);
6537 hwc->interrupts = MAX_INTERRUPTS;
6538 perf_log_throttle(event, 0);
6539 tick_nohz_full_kick();
6544 if (event->attr.freq) {
6545 u64 now = perf_clock();
6546 s64 delta = now - hwc->freq_time_stamp;
6548 hwc->freq_time_stamp = now;
6550 if (delta > 0 && delta < 2*TICK_NSEC)
6551 perf_adjust_period(event, delta, hwc->last_period, true);
6555 * XXX event_limit might not quite work as expected on inherited
6559 event->pending_kill = POLL_IN;
6560 if (events && atomic_dec_and_test(&event->event_limit)) {
6562 event->pending_kill = POLL_HUP;
6563 event->pending_disable = 1;
6564 irq_work_queue(&event->pending);
6567 if (event->overflow_handler)
6568 event->overflow_handler(event, data, regs);
6570 perf_event_output(event, data, regs);
6572 if (*perf_event_fasync(event) && event->pending_kill) {
6573 event->pending_wakeup = 1;
6574 irq_work_queue(&event->pending);
6580 int perf_event_overflow(struct perf_event *event,
6581 struct perf_sample_data *data,
6582 struct pt_regs *regs)
6584 return __perf_event_overflow(event, 1, data, regs);
6588 * Generic software event infrastructure
6591 struct swevent_htable {
6592 struct swevent_hlist *swevent_hlist;
6593 struct mutex hlist_mutex;
6596 /* Recursion avoidance in each contexts */
6597 int recursion[PERF_NR_CONTEXTS];
6600 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
6603 * We directly increment event->count and keep a second value in
6604 * event->hw.period_left to count intervals. This period event
6605 * is kept in the range [-sample_period, 0] so that we can use the
6609 u64 perf_swevent_set_period(struct perf_event *event)
6611 struct hw_perf_event *hwc = &event->hw;
6612 u64 period = hwc->last_period;
6616 hwc->last_period = hwc->sample_period;
6619 old = val = local64_read(&hwc->period_left);
6623 nr = div64_u64(period + val, period);
6624 offset = nr * period;
6626 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
6632 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
6633 struct perf_sample_data *data,
6634 struct pt_regs *regs)
6636 struct hw_perf_event *hwc = &event->hw;
6640 overflow = perf_swevent_set_period(event);
6642 if (hwc->interrupts == MAX_INTERRUPTS)
6645 for (; overflow; overflow--) {
6646 if (__perf_event_overflow(event, throttle,
6649 * We inhibit the overflow from happening when
6650 * hwc->interrupts == MAX_INTERRUPTS.
6658 static void perf_swevent_event(struct perf_event *event, u64 nr,
6659 struct perf_sample_data *data,
6660 struct pt_regs *regs)
6662 struct hw_perf_event *hwc = &event->hw;
6664 local64_add(nr, &event->count);
6669 if (!is_sampling_event(event))
6672 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
6674 return perf_swevent_overflow(event, 1, data, regs);
6676 data->period = event->hw.last_period;
6678 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
6679 return perf_swevent_overflow(event, 1, data, regs);
6681 if (local64_add_negative(nr, &hwc->period_left))
6684 perf_swevent_overflow(event, 0, data, regs);
6687 static int perf_exclude_event(struct perf_event *event,
6688 struct pt_regs *regs)
6690 if (event->hw.state & PERF_HES_STOPPED)
6694 if (event->attr.exclude_user && user_mode(regs))
6697 if (event->attr.exclude_kernel && !user_mode(regs))
6704 static int perf_swevent_match(struct perf_event *event,
6705 enum perf_type_id type,
6707 struct perf_sample_data *data,
6708 struct pt_regs *regs)
6710 if (event->attr.type != type)
6713 if (event->attr.config != event_id)
6716 if (perf_exclude_event(event, regs))
6722 static inline u64 swevent_hash(u64 type, u32 event_id)
6724 u64 val = event_id | (type << 32);
6726 return hash_64(val, SWEVENT_HLIST_BITS);
6729 static inline struct hlist_head *
6730 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
6732 u64 hash = swevent_hash(type, event_id);
6734 return &hlist->heads[hash];
6737 /* For the read side: events when they trigger */
6738 static inline struct hlist_head *
6739 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
6741 struct swevent_hlist *hlist;
6743 hlist = rcu_dereference(swhash->swevent_hlist);
6747 return __find_swevent_head(hlist, type, event_id);
6750 /* For the event head insertion and removal in the hlist */
6751 static inline struct hlist_head *
6752 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
6754 struct swevent_hlist *hlist;
6755 u32 event_id = event->attr.config;
6756 u64 type = event->attr.type;
6759 * Event scheduling is always serialized against hlist allocation
6760 * and release. Which makes the protected version suitable here.
6761 * The context lock guarantees that.
6763 hlist = rcu_dereference_protected(swhash->swevent_hlist,
6764 lockdep_is_held(&event->ctx->lock));
6768 return __find_swevent_head(hlist, type, event_id);
6771 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
6773 struct perf_sample_data *data,
6774 struct pt_regs *regs)
6776 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6777 struct perf_event *event;
6778 struct hlist_head *head;
6781 head = find_swevent_head_rcu(swhash, type, event_id);
6785 hlist_for_each_entry_rcu(event, head, hlist_entry) {
6786 if (perf_swevent_match(event, type, event_id, data, regs))
6787 perf_swevent_event(event, nr, data, regs);
6793 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
6795 int perf_swevent_get_recursion_context(void)
6797 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6799 return get_recursion_context(swhash->recursion);
6801 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
6803 inline void perf_swevent_put_recursion_context(int rctx)
6805 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6807 put_recursion_context(swhash->recursion, rctx);
6810 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6812 struct perf_sample_data data;
6814 if (WARN_ON_ONCE(!regs))
6817 perf_sample_data_init(&data, addr, 0);
6818 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
6821 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
6825 preempt_disable_notrace();
6826 rctx = perf_swevent_get_recursion_context();
6827 if (unlikely(rctx < 0))
6830 ___perf_sw_event(event_id, nr, regs, addr);
6832 perf_swevent_put_recursion_context(rctx);
6834 preempt_enable_notrace();
6837 static void perf_swevent_read(struct perf_event *event)
6841 static int perf_swevent_add(struct perf_event *event, int flags)
6843 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
6844 struct hw_perf_event *hwc = &event->hw;
6845 struct hlist_head *head;
6847 if (is_sampling_event(event)) {
6848 hwc->last_period = hwc->sample_period;
6849 perf_swevent_set_period(event);
6852 hwc->state = !(flags & PERF_EF_START);
6854 head = find_swevent_head(swhash, event);
6855 if (WARN_ON_ONCE(!head))
6858 hlist_add_head_rcu(&event->hlist_entry, head);
6859 perf_event_update_userpage(event);
6864 static void perf_swevent_del(struct perf_event *event, int flags)
6866 hlist_del_rcu(&event->hlist_entry);
6869 static void perf_swevent_start(struct perf_event *event, int flags)
6871 event->hw.state = 0;
6874 static void perf_swevent_stop(struct perf_event *event, int flags)
6876 event->hw.state = PERF_HES_STOPPED;
6879 /* Deref the hlist from the update side */
6880 static inline struct swevent_hlist *
6881 swevent_hlist_deref(struct swevent_htable *swhash)
6883 return rcu_dereference_protected(swhash->swevent_hlist,
6884 lockdep_is_held(&swhash->hlist_mutex));
6887 static void swevent_hlist_release(struct swevent_htable *swhash)
6889 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
6894 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
6895 kfree_rcu(hlist, rcu_head);
6898 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
6900 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6902 mutex_lock(&swhash->hlist_mutex);
6904 if (!--swhash->hlist_refcount)
6905 swevent_hlist_release(swhash);
6907 mutex_unlock(&swhash->hlist_mutex);
6910 static void swevent_hlist_put(struct perf_event *event)
6914 for_each_possible_cpu(cpu)
6915 swevent_hlist_put_cpu(event, cpu);
6918 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
6920 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6923 mutex_lock(&swhash->hlist_mutex);
6924 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
6925 struct swevent_hlist *hlist;
6927 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
6932 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6934 swhash->hlist_refcount++;
6936 mutex_unlock(&swhash->hlist_mutex);
6941 static int swevent_hlist_get(struct perf_event *event)
6944 int cpu, failed_cpu;
6947 for_each_possible_cpu(cpu) {
6948 err = swevent_hlist_get_cpu(event, cpu);
6958 for_each_possible_cpu(cpu) {
6959 if (cpu == failed_cpu)
6961 swevent_hlist_put_cpu(event, cpu);
6968 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
6970 static void sw_perf_event_destroy(struct perf_event *event)
6972 u64 event_id = event->attr.config;
6974 WARN_ON(event->parent);
6976 static_key_slow_dec(&perf_swevent_enabled[event_id]);
6977 swevent_hlist_put(event);
6980 static int perf_swevent_init(struct perf_event *event)
6982 u64 event_id = event->attr.config;
6984 if (event->attr.type != PERF_TYPE_SOFTWARE)
6988 * no branch sampling for software events
6990 if (has_branch_stack(event))
6994 case PERF_COUNT_SW_CPU_CLOCK:
6995 case PERF_COUNT_SW_TASK_CLOCK:
7002 if (event_id >= PERF_COUNT_SW_MAX)
7005 if (!event->parent) {
7008 err = swevent_hlist_get(event);
7012 static_key_slow_inc(&perf_swevent_enabled[event_id]);
7013 event->destroy = sw_perf_event_destroy;
7019 static struct pmu perf_swevent = {
7020 .task_ctx_nr = perf_sw_context,
7022 .capabilities = PERF_PMU_CAP_NO_NMI,
7024 .event_init = perf_swevent_init,
7025 .add = perf_swevent_add,
7026 .del = perf_swevent_del,
7027 .start = perf_swevent_start,
7028 .stop = perf_swevent_stop,
7029 .read = perf_swevent_read,
7032 #ifdef CONFIG_EVENT_TRACING
7034 static int perf_tp_filter_match(struct perf_event *event,
7035 struct perf_sample_data *data)
7037 void *record = data->raw->data;
7039 /* only top level events have filters set */
7041 event = event->parent;
7043 if (likely(!event->filter) || filter_match_preds(event->filter, record))
7048 static int perf_tp_event_match(struct perf_event *event,
7049 struct perf_sample_data *data,
7050 struct pt_regs *regs)
7052 if (event->hw.state & PERF_HES_STOPPED)
7055 * All tracepoints are from kernel-space.
7057 if (event->attr.exclude_kernel)
7060 if (!perf_tp_filter_match(event, data))
7066 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
7067 struct pt_regs *regs, struct hlist_head *head, int rctx,
7068 struct task_struct *task)
7070 struct perf_sample_data data;
7071 struct perf_event *event;
7073 struct perf_raw_record raw = {
7078 perf_sample_data_init(&data, addr, 0);
7081 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7082 if (perf_tp_event_match(event, &data, regs))
7083 perf_swevent_event(event, count, &data, regs);
7087 * If we got specified a target task, also iterate its context and
7088 * deliver this event there too.
7090 if (task && task != current) {
7091 struct perf_event_context *ctx;
7092 struct trace_entry *entry = record;
7095 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
7099 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7100 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7102 if (event->attr.config != entry->type)
7104 if (perf_tp_event_match(event, &data, regs))
7105 perf_swevent_event(event, count, &data, regs);
7111 perf_swevent_put_recursion_context(rctx);
7113 EXPORT_SYMBOL_GPL(perf_tp_event);
7115 static void tp_perf_event_destroy(struct perf_event *event)
7117 perf_trace_destroy(event);
7120 static int perf_tp_event_init(struct perf_event *event)
7124 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7128 * no branch sampling for tracepoint events
7130 if (has_branch_stack(event))
7133 err = perf_trace_init(event);
7137 event->destroy = tp_perf_event_destroy;
7142 static struct pmu perf_tracepoint = {
7143 .task_ctx_nr = perf_sw_context,
7145 .event_init = perf_tp_event_init,
7146 .add = perf_trace_add,
7147 .del = perf_trace_del,
7148 .start = perf_swevent_start,
7149 .stop = perf_swevent_stop,
7150 .read = perf_swevent_read,
7153 static inline void perf_tp_register(void)
7155 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
7158 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7163 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7166 filter_str = strndup_user(arg, PAGE_SIZE);
7167 if (IS_ERR(filter_str))
7168 return PTR_ERR(filter_str);
7170 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
7176 static void perf_event_free_filter(struct perf_event *event)
7178 ftrace_profile_free_filter(event);
7181 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7183 struct bpf_prog *prog;
7185 if (event->attr.type != PERF_TYPE_TRACEPOINT)
7188 if (event->tp_event->prog)
7191 if (!(event->tp_event->flags & TRACE_EVENT_FL_UKPROBE))
7192 /* bpf programs can only be attached to u/kprobes */
7195 prog = bpf_prog_get(prog_fd);
7197 return PTR_ERR(prog);
7199 if (prog->type != BPF_PROG_TYPE_KPROBE) {
7200 /* valid fd, but invalid bpf program type */
7205 event->tp_event->prog = prog;
7210 static void perf_event_free_bpf_prog(struct perf_event *event)
7212 struct bpf_prog *prog;
7214 if (!event->tp_event)
7217 prog = event->tp_event->prog;
7219 event->tp_event->prog = NULL;
7226 static inline void perf_tp_register(void)
7230 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
7235 static void perf_event_free_filter(struct perf_event *event)
7239 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
7244 static void perf_event_free_bpf_prog(struct perf_event *event)
7247 #endif /* CONFIG_EVENT_TRACING */
7249 #ifdef CONFIG_HAVE_HW_BREAKPOINT
7250 void perf_bp_event(struct perf_event *bp, void *data)
7252 struct perf_sample_data sample;
7253 struct pt_regs *regs = data;
7255 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
7257 if (!bp->hw.state && !perf_exclude_event(bp, regs))
7258 perf_swevent_event(bp, 1, &sample, regs);
7263 * hrtimer based swevent callback
7266 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
7268 enum hrtimer_restart ret = HRTIMER_RESTART;
7269 struct perf_sample_data data;
7270 struct pt_regs *regs;
7271 struct perf_event *event;
7274 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
7276 if (event->state != PERF_EVENT_STATE_ACTIVE)
7277 return HRTIMER_NORESTART;
7279 event->pmu->read(event);
7281 perf_sample_data_init(&data, 0, event->hw.last_period);
7282 regs = get_irq_regs();
7284 if (regs && !perf_exclude_event(event, regs)) {
7285 if (!(event->attr.exclude_idle && is_idle_task(current)))
7286 if (__perf_event_overflow(event, 1, &data, regs))
7287 ret = HRTIMER_NORESTART;
7290 period = max_t(u64, 10000, event->hw.sample_period);
7291 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
7296 static void perf_swevent_start_hrtimer(struct perf_event *event)
7298 struct hw_perf_event *hwc = &event->hw;
7301 if (!is_sampling_event(event))
7304 period = local64_read(&hwc->period_left);
7309 local64_set(&hwc->period_left, 0);
7311 period = max_t(u64, 10000, hwc->sample_period);
7313 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
7314 HRTIMER_MODE_REL_PINNED);
7317 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
7319 struct hw_perf_event *hwc = &event->hw;
7321 if (is_sampling_event(event)) {
7322 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
7323 local64_set(&hwc->period_left, ktime_to_ns(remaining));
7325 hrtimer_cancel(&hwc->hrtimer);
7329 static void perf_swevent_init_hrtimer(struct perf_event *event)
7331 struct hw_perf_event *hwc = &event->hw;
7333 if (!is_sampling_event(event))
7336 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
7337 hwc->hrtimer.function = perf_swevent_hrtimer;
7340 * Since hrtimers have a fixed rate, we can do a static freq->period
7341 * mapping and avoid the whole period adjust feedback stuff.
7343 if (event->attr.freq) {
7344 long freq = event->attr.sample_freq;
7346 event->attr.sample_period = NSEC_PER_SEC / freq;
7347 hwc->sample_period = event->attr.sample_period;
7348 local64_set(&hwc->period_left, hwc->sample_period);
7349 hwc->last_period = hwc->sample_period;
7350 event->attr.freq = 0;
7355 * Software event: cpu wall time clock
7358 static void cpu_clock_event_update(struct perf_event *event)
7363 now = local_clock();
7364 prev = local64_xchg(&event->hw.prev_count, now);
7365 local64_add(now - prev, &event->count);
7368 static void cpu_clock_event_start(struct perf_event *event, int flags)
7370 local64_set(&event->hw.prev_count, local_clock());
7371 perf_swevent_start_hrtimer(event);
7374 static void cpu_clock_event_stop(struct perf_event *event, int flags)
7376 perf_swevent_cancel_hrtimer(event);
7377 cpu_clock_event_update(event);
7380 static int cpu_clock_event_add(struct perf_event *event, int flags)
7382 if (flags & PERF_EF_START)
7383 cpu_clock_event_start(event, flags);
7384 perf_event_update_userpage(event);
7389 static void cpu_clock_event_del(struct perf_event *event, int flags)
7391 cpu_clock_event_stop(event, flags);
7394 static void cpu_clock_event_read(struct perf_event *event)
7396 cpu_clock_event_update(event);
7399 static int cpu_clock_event_init(struct perf_event *event)
7401 if (event->attr.type != PERF_TYPE_SOFTWARE)
7404 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
7408 * no branch sampling for software events
7410 if (has_branch_stack(event))
7413 perf_swevent_init_hrtimer(event);
7418 static struct pmu perf_cpu_clock = {
7419 .task_ctx_nr = perf_sw_context,
7421 .capabilities = PERF_PMU_CAP_NO_NMI,
7423 .event_init = cpu_clock_event_init,
7424 .add = cpu_clock_event_add,
7425 .del = cpu_clock_event_del,
7426 .start = cpu_clock_event_start,
7427 .stop = cpu_clock_event_stop,
7428 .read = cpu_clock_event_read,
7432 * Software event: task time clock
7435 static void task_clock_event_update(struct perf_event *event, u64 now)
7440 prev = local64_xchg(&event->hw.prev_count, now);
7442 local64_add(delta, &event->count);
7445 static void task_clock_event_start(struct perf_event *event, int flags)
7447 local64_set(&event->hw.prev_count, event->ctx->time);
7448 perf_swevent_start_hrtimer(event);
7451 static void task_clock_event_stop(struct perf_event *event, int flags)
7453 perf_swevent_cancel_hrtimer(event);
7454 task_clock_event_update(event, event->ctx->time);
7457 static int task_clock_event_add(struct perf_event *event, int flags)
7459 if (flags & PERF_EF_START)
7460 task_clock_event_start(event, flags);
7461 perf_event_update_userpage(event);
7466 static void task_clock_event_del(struct perf_event *event, int flags)
7468 task_clock_event_stop(event, PERF_EF_UPDATE);
7471 static void task_clock_event_read(struct perf_event *event)
7473 u64 now = perf_clock();
7474 u64 delta = now - event->ctx->timestamp;
7475 u64 time = event->ctx->time + delta;
7477 task_clock_event_update(event, time);
7480 static int task_clock_event_init(struct perf_event *event)
7482 if (event->attr.type != PERF_TYPE_SOFTWARE)
7485 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
7489 * no branch sampling for software events
7491 if (has_branch_stack(event))
7494 perf_swevent_init_hrtimer(event);
7499 static struct pmu perf_task_clock = {
7500 .task_ctx_nr = perf_sw_context,
7502 .capabilities = PERF_PMU_CAP_NO_NMI,
7504 .event_init = task_clock_event_init,
7505 .add = task_clock_event_add,
7506 .del = task_clock_event_del,
7507 .start = task_clock_event_start,
7508 .stop = task_clock_event_stop,
7509 .read = task_clock_event_read,
7512 static void perf_pmu_nop_void(struct pmu *pmu)
7516 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
7520 static int perf_pmu_nop_int(struct pmu *pmu)
7525 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
7527 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
7529 __this_cpu_write(nop_txn_flags, flags);
7531 if (flags & ~PERF_PMU_TXN_ADD)
7534 perf_pmu_disable(pmu);
7537 static int perf_pmu_commit_txn(struct pmu *pmu)
7539 unsigned int flags = __this_cpu_read(nop_txn_flags);
7541 __this_cpu_write(nop_txn_flags, 0);
7543 if (flags & ~PERF_PMU_TXN_ADD)
7546 perf_pmu_enable(pmu);
7550 static void perf_pmu_cancel_txn(struct pmu *pmu)
7552 unsigned int flags = __this_cpu_read(nop_txn_flags);
7554 __this_cpu_write(nop_txn_flags, 0);
7556 if (flags & ~PERF_PMU_TXN_ADD)
7559 perf_pmu_enable(pmu);
7562 static int perf_event_idx_default(struct perf_event *event)
7568 * Ensures all contexts with the same task_ctx_nr have the same
7569 * pmu_cpu_context too.
7571 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
7578 list_for_each_entry(pmu, &pmus, entry) {
7579 if (pmu->task_ctx_nr == ctxn)
7580 return pmu->pmu_cpu_context;
7586 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
7590 for_each_possible_cpu(cpu) {
7591 struct perf_cpu_context *cpuctx;
7593 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7595 if (cpuctx->unique_pmu == old_pmu)
7596 cpuctx->unique_pmu = pmu;
7600 static void free_pmu_context(struct pmu *pmu)
7604 mutex_lock(&pmus_lock);
7606 * Like a real lame refcount.
7608 list_for_each_entry(i, &pmus, entry) {
7609 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
7610 update_pmu_context(i, pmu);
7615 free_percpu(pmu->pmu_cpu_context);
7617 mutex_unlock(&pmus_lock);
7619 static struct idr pmu_idr;
7622 type_show(struct device *dev, struct device_attribute *attr, char *page)
7624 struct pmu *pmu = dev_get_drvdata(dev);
7626 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
7628 static DEVICE_ATTR_RO(type);
7631 perf_event_mux_interval_ms_show(struct device *dev,
7632 struct device_attribute *attr,
7635 struct pmu *pmu = dev_get_drvdata(dev);
7637 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
7640 static DEFINE_MUTEX(mux_interval_mutex);
7643 perf_event_mux_interval_ms_store(struct device *dev,
7644 struct device_attribute *attr,
7645 const char *buf, size_t count)
7647 struct pmu *pmu = dev_get_drvdata(dev);
7648 int timer, cpu, ret;
7650 ret = kstrtoint(buf, 0, &timer);
7657 /* same value, noting to do */
7658 if (timer == pmu->hrtimer_interval_ms)
7661 mutex_lock(&mux_interval_mutex);
7662 pmu->hrtimer_interval_ms = timer;
7664 /* update all cpuctx for this PMU */
7666 for_each_online_cpu(cpu) {
7667 struct perf_cpu_context *cpuctx;
7668 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7669 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
7671 cpu_function_call(cpu,
7672 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
7675 mutex_unlock(&mux_interval_mutex);
7679 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
7681 static struct attribute *pmu_dev_attrs[] = {
7682 &dev_attr_type.attr,
7683 &dev_attr_perf_event_mux_interval_ms.attr,
7686 ATTRIBUTE_GROUPS(pmu_dev);
7688 static int pmu_bus_running;
7689 static struct bus_type pmu_bus = {
7690 .name = "event_source",
7691 .dev_groups = pmu_dev_groups,
7694 static void pmu_dev_release(struct device *dev)
7699 static int pmu_dev_alloc(struct pmu *pmu)
7703 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
7707 pmu->dev->groups = pmu->attr_groups;
7708 device_initialize(pmu->dev);
7709 ret = dev_set_name(pmu->dev, "%s", pmu->name);
7713 dev_set_drvdata(pmu->dev, pmu);
7714 pmu->dev->bus = &pmu_bus;
7715 pmu->dev->release = pmu_dev_release;
7716 ret = device_add(pmu->dev);
7724 put_device(pmu->dev);
7728 static struct lock_class_key cpuctx_mutex;
7729 static struct lock_class_key cpuctx_lock;
7731 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
7735 mutex_lock(&pmus_lock);
7737 pmu->pmu_disable_count = alloc_percpu(int);
7738 if (!pmu->pmu_disable_count)
7747 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
7755 if (pmu_bus_running) {
7756 ret = pmu_dev_alloc(pmu);
7762 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
7763 if (pmu->pmu_cpu_context)
7764 goto got_cpu_context;
7767 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
7768 if (!pmu->pmu_cpu_context)
7771 for_each_possible_cpu(cpu) {
7772 struct perf_cpu_context *cpuctx;
7774 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
7775 __perf_event_init_context(&cpuctx->ctx);
7776 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
7777 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
7778 cpuctx->ctx.pmu = pmu;
7780 __perf_mux_hrtimer_init(cpuctx, cpu);
7782 cpuctx->unique_pmu = pmu;
7786 if (!pmu->start_txn) {
7787 if (pmu->pmu_enable) {
7789 * If we have pmu_enable/pmu_disable calls, install
7790 * transaction stubs that use that to try and batch
7791 * hardware accesses.
7793 pmu->start_txn = perf_pmu_start_txn;
7794 pmu->commit_txn = perf_pmu_commit_txn;
7795 pmu->cancel_txn = perf_pmu_cancel_txn;
7797 pmu->start_txn = perf_pmu_nop_txn;
7798 pmu->commit_txn = perf_pmu_nop_int;
7799 pmu->cancel_txn = perf_pmu_nop_void;
7803 if (!pmu->pmu_enable) {
7804 pmu->pmu_enable = perf_pmu_nop_void;
7805 pmu->pmu_disable = perf_pmu_nop_void;
7808 if (!pmu->event_idx)
7809 pmu->event_idx = perf_event_idx_default;
7811 list_add_rcu(&pmu->entry, &pmus);
7812 atomic_set(&pmu->exclusive_cnt, 0);
7815 mutex_unlock(&pmus_lock);
7820 device_del(pmu->dev);
7821 put_device(pmu->dev);
7824 if (pmu->type >= PERF_TYPE_MAX)
7825 idr_remove(&pmu_idr, pmu->type);
7828 free_percpu(pmu->pmu_disable_count);
7831 EXPORT_SYMBOL_GPL(perf_pmu_register);
7833 void perf_pmu_unregister(struct pmu *pmu)
7835 mutex_lock(&pmus_lock);
7836 list_del_rcu(&pmu->entry);
7837 mutex_unlock(&pmus_lock);
7840 * We dereference the pmu list under both SRCU and regular RCU, so
7841 * synchronize against both of those.
7843 synchronize_srcu(&pmus_srcu);
7846 free_percpu(pmu->pmu_disable_count);
7847 if (pmu->type >= PERF_TYPE_MAX)
7848 idr_remove(&pmu_idr, pmu->type);
7849 device_del(pmu->dev);
7850 put_device(pmu->dev);
7851 free_pmu_context(pmu);
7853 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
7855 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
7857 struct perf_event_context *ctx = NULL;
7860 if (!try_module_get(pmu->module))
7863 if (event->group_leader != event) {
7865 * This ctx->mutex can nest when we're called through
7866 * inheritance. See the perf_event_ctx_lock_nested() comment.
7868 ctx = perf_event_ctx_lock_nested(event->group_leader,
7869 SINGLE_DEPTH_NESTING);
7874 ret = pmu->event_init(event);
7877 perf_event_ctx_unlock(event->group_leader, ctx);
7880 module_put(pmu->module);
7885 static struct pmu *perf_init_event(struct perf_event *event)
7887 struct pmu *pmu = NULL;
7891 idx = srcu_read_lock(&pmus_srcu);
7894 pmu = idr_find(&pmu_idr, event->attr.type);
7897 ret = perf_try_init_event(pmu, event);
7903 list_for_each_entry_rcu(pmu, &pmus, entry) {
7904 ret = perf_try_init_event(pmu, event);
7908 if (ret != -ENOENT) {
7913 pmu = ERR_PTR(-ENOENT);
7915 srcu_read_unlock(&pmus_srcu, idx);
7920 static void account_event_cpu(struct perf_event *event, int cpu)
7925 if (is_cgroup_event(event))
7926 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
7929 static void account_event(struct perf_event *event)
7934 if (event->attach_state & PERF_ATTACH_TASK)
7935 static_key_slow_inc(&perf_sched_events.key);
7936 if (event->attr.mmap || event->attr.mmap_data)
7937 atomic_inc(&nr_mmap_events);
7938 if (event->attr.comm)
7939 atomic_inc(&nr_comm_events);
7940 if (event->attr.task)
7941 atomic_inc(&nr_task_events);
7942 if (event->attr.freq) {
7943 if (atomic_inc_return(&nr_freq_events) == 1)
7944 tick_nohz_full_kick_all();
7946 if (event->attr.context_switch) {
7947 atomic_inc(&nr_switch_events);
7948 static_key_slow_inc(&perf_sched_events.key);
7950 if (has_branch_stack(event))
7951 static_key_slow_inc(&perf_sched_events.key);
7952 if (is_cgroup_event(event))
7953 static_key_slow_inc(&perf_sched_events.key);
7955 account_event_cpu(event, event->cpu);
7959 * Allocate and initialize a event structure
7961 static struct perf_event *
7962 perf_event_alloc(struct perf_event_attr *attr, int cpu,
7963 struct task_struct *task,
7964 struct perf_event *group_leader,
7965 struct perf_event *parent_event,
7966 perf_overflow_handler_t overflow_handler,
7967 void *context, int cgroup_fd)
7970 struct perf_event *event;
7971 struct hw_perf_event *hwc;
7974 if ((unsigned)cpu >= nr_cpu_ids) {
7975 if (!task || cpu != -1)
7976 return ERR_PTR(-EINVAL);
7979 event = kzalloc(sizeof(*event), GFP_KERNEL);
7981 return ERR_PTR(-ENOMEM);
7984 * Single events are their own group leaders, with an
7985 * empty sibling list:
7988 group_leader = event;
7990 mutex_init(&event->child_mutex);
7991 INIT_LIST_HEAD(&event->child_list);
7993 INIT_LIST_HEAD(&event->group_entry);
7994 INIT_LIST_HEAD(&event->event_entry);
7995 INIT_LIST_HEAD(&event->sibling_list);
7996 INIT_LIST_HEAD(&event->rb_entry);
7997 INIT_LIST_HEAD(&event->active_entry);
7998 INIT_HLIST_NODE(&event->hlist_entry);
8001 init_waitqueue_head(&event->waitq);
8002 init_irq_work(&event->pending, perf_pending_event);
8004 mutex_init(&event->mmap_mutex);
8006 atomic_long_set(&event->refcount, 1);
8008 event->attr = *attr;
8009 event->group_leader = group_leader;
8013 event->parent = parent_event;
8015 event->ns = get_pid_ns(task_active_pid_ns(current));
8016 event->id = atomic64_inc_return(&perf_event_id);
8018 event->state = PERF_EVENT_STATE_INACTIVE;
8021 event->attach_state = PERF_ATTACH_TASK;
8023 * XXX pmu::event_init needs to know what task to account to
8024 * and we cannot use the ctx information because we need the
8025 * pmu before we get a ctx.
8027 event->hw.target = task;
8030 event->clock = &local_clock;
8032 event->clock = parent_event->clock;
8034 if (!overflow_handler && parent_event) {
8035 overflow_handler = parent_event->overflow_handler;
8036 context = parent_event->overflow_handler_context;
8039 event->overflow_handler = overflow_handler;
8040 event->overflow_handler_context = context;
8042 perf_event__state_init(event);
8047 hwc->sample_period = attr->sample_period;
8048 if (attr->freq && attr->sample_freq)
8049 hwc->sample_period = 1;
8050 hwc->last_period = hwc->sample_period;
8052 local64_set(&hwc->period_left, hwc->sample_period);
8055 * we currently do not support PERF_FORMAT_GROUP on inherited events
8057 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
8060 if (!has_branch_stack(event))
8061 event->attr.branch_sample_type = 0;
8063 if (cgroup_fd != -1) {
8064 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
8069 pmu = perf_init_event(event);
8072 else if (IS_ERR(pmu)) {
8077 err = exclusive_event_init(event);
8081 if (!event->parent) {
8082 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
8083 err = get_callchain_buffers();
8089 /* symmetric to unaccount_event() in _free_event() */
8090 account_event(event);
8095 exclusive_event_destroy(event);
8099 event->destroy(event);
8100 module_put(pmu->module);
8102 if (is_cgroup_event(event))
8103 perf_detach_cgroup(event);
8105 put_pid_ns(event->ns);
8108 return ERR_PTR(err);
8111 static int perf_copy_attr(struct perf_event_attr __user *uattr,
8112 struct perf_event_attr *attr)
8117 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
8121 * zero the full structure, so that a short copy will be nice.
8123 memset(attr, 0, sizeof(*attr));
8125 ret = get_user(size, &uattr->size);
8129 if (size > PAGE_SIZE) /* silly large */
8132 if (!size) /* abi compat */
8133 size = PERF_ATTR_SIZE_VER0;
8135 if (size < PERF_ATTR_SIZE_VER0)
8139 * If we're handed a bigger struct than we know of,
8140 * ensure all the unknown bits are 0 - i.e. new
8141 * user-space does not rely on any kernel feature
8142 * extensions we dont know about yet.
8144 if (size > sizeof(*attr)) {
8145 unsigned char __user *addr;
8146 unsigned char __user *end;
8149 addr = (void __user *)uattr + sizeof(*attr);
8150 end = (void __user *)uattr + size;
8152 for (; addr < end; addr++) {
8153 ret = get_user(val, addr);
8159 size = sizeof(*attr);
8162 ret = copy_from_user(attr, uattr, size);
8166 if (attr->__reserved_1)
8169 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
8172 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
8175 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
8176 u64 mask = attr->branch_sample_type;
8178 /* only using defined bits */
8179 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
8182 /* at least one branch bit must be set */
8183 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
8186 /* propagate priv level, when not set for branch */
8187 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
8189 /* exclude_kernel checked on syscall entry */
8190 if (!attr->exclude_kernel)
8191 mask |= PERF_SAMPLE_BRANCH_KERNEL;
8193 if (!attr->exclude_user)
8194 mask |= PERF_SAMPLE_BRANCH_USER;
8196 if (!attr->exclude_hv)
8197 mask |= PERF_SAMPLE_BRANCH_HV;
8199 * adjust user setting (for HW filter setup)
8201 attr->branch_sample_type = mask;
8203 /* privileged levels capture (kernel, hv): check permissions */
8204 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
8205 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8209 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
8210 ret = perf_reg_validate(attr->sample_regs_user);
8215 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
8216 if (!arch_perf_have_user_stack_dump())
8220 * We have __u32 type for the size, but so far
8221 * we can only use __u16 as maximum due to the
8222 * __u16 sample size limit.
8224 if (attr->sample_stack_user >= USHRT_MAX)
8226 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
8230 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
8231 ret = perf_reg_validate(attr->sample_regs_intr);
8236 put_user(sizeof(*attr), &uattr->size);
8242 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
8244 struct ring_buffer *rb = NULL;
8250 /* don't allow circular references */
8251 if (event == output_event)
8255 * Don't allow cross-cpu buffers
8257 if (output_event->cpu != event->cpu)
8261 * If its not a per-cpu rb, it must be the same task.
8263 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
8267 * Mixing clocks in the same buffer is trouble you don't need.
8269 if (output_event->clock != event->clock)
8273 * If both events generate aux data, they must be on the same PMU
8275 if (has_aux(event) && has_aux(output_event) &&
8276 event->pmu != output_event->pmu)
8280 mutex_lock(&event->mmap_mutex);
8281 /* Can't redirect output if we've got an active mmap() */
8282 if (atomic_read(&event->mmap_count))
8286 /* get the rb we want to redirect to */
8287 rb = ring_buffer_get(output_event);
8292 ring_buffer_attach(event, rb);
8296 mutex_unlock(&event->mmap_mutex);
8302 static void mutex_lock_double(struct mutex *a, struct mutex *b)
8308 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
8311 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
8313 bool nmi_safe = false;
8316 case CLOCK_MONOTONIC:
8317 event->clock = &ktime_get_mono_fast_ns;
8321 case CLOCK_MONOTONIC_RAW:
8322 event->clock = &ktime_get_raw_fast_ns;
8326 case CLOCK_REALTIME:
8327 event->clock = &ktime_get_real_ns;
8330 case CLOCK_BOOTTIME:
8331 event->clock = &ktime_get_boot_ns;
8335 event->clock = &ktime_get_tai_ns;
8342 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
8349 * sys_perf_event_open - open a performance event, associate it to a task/cpu
8351 * @attr_uptr: event_id type attributes for monitoring/sampling
8354 * @group_fd: group leader event fd
8356 SYSCALL_DEFINE5(perf_event_open,
8357 struct perf_event_attr __user *, attr_uptr,
8358 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
8360 struct perf_event *group_leader = NULL, *output_event = NULL;
8361 struct perf_event *event, *sibling;
8362 struct perf_event_attr attr;
8363 struct perf_event_context *ctx, *uninitialized_var(gctx);
8364 struct file *event_file = NULL;
8365 struct fd group = {NULL, 0};
8366 struct task_struct *task = NULL;
8371 int f_flags = O_RDWR;
8374 /* for future expandability... */
8375 if (flags & ~PERF_FLAG_ALL)
8378 err = perf_copy_attr(attr_uptr, &attr);
8382 if (!attr.exclude_kernel) {
8383 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
8388 if (attr.sample_freq > sysctl_perf_event_sample_rate)
8391 if (attr.sample_period & (1ULL << 63))
8396 * In cgroup mode, the pid argument is used to pass the fd
8397 * opened to the cgroup directory in cgroupfs. The cpu argument
8398 * designates the cpu on which to monitor threads from that
8401 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
8404 if (flags & PERF_FLAG_FD_CLOEXEC)
8405 f_flags |= O_CLOEXEC;
8407 event_fd = get_unused_fd_flags(f_flags);
8411 if (group_fd != -1) {
8412 err = perf_fget_light(group_fd, &group);
8415 group_leader = group.file->private_data;
8416 if (flags & PERF_FLAG_FD_OUTPUT)
8417 output_event = group_leader;
8418 if (flags & PERF_FLAG_FD_NO_GROUP)
8419 group_leader = NULL;
8422 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
8423 task = find_lively_task_by_vpid(pid);
8425 err = PTR_ERR(task);
8430 if (task && group_leader &&
8431 group_leader->attr.inherit != attr.inherit) {
8439 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
8444 * Reuse ptrace permission checks for now.
8446 * We must hold cred_guard_mutex across this and any potential
8447 * perf_install_in_context() call for this new event to
8448 * serialize against exec() altering our credentials (and the
8449 * perf_event_exit_task() that could imply).
8452 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
8456 if (flags & PERF_FLAG_PID_CGROUP)
8459 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
8460 NULL, NULL, cgroup_fd);
8461 if (IS_ERR(event)) {
8462 err = PTR_ERR(event);
8466 if (is_sampling_event(event)) {
8467 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
8474 * Special case software events and allow them to be part of
8475 * any hardware group.
8479 if (attr.use_clockid) {
8480 err = perf_event_set_clock(event, attr.clockid);
8486 (is_software_event(event) != is_software_event(group_leader))) {
8487 if (is_software_event(event)) {
8489 * If event and group_leader are not both a software
8490 * event, and event is, then group leader is not.
8492 * Allow the addition of software events to !software
8493 * groups, this is safe because software events never
8496 pmu = group_leader->pmu;
8497 } else if (is_software_event(group_leader) &&
8498 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
8500 * In case the group is a pure software group, and we
8501 * try to add a hardware event, move the whole group to
8502 * the hardware context.
8509 * Get the target context (task or percpu):
8511 ctx = find_get_context(pmu, task, event);
8517 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
8523 * Look up the group leader (we will attach this event to it):
8529 * Do not allow a recursive hierarchy (this new sibling
8530 * becoming part of another group-sibling):
8532 if (group_leader->group_leader != group_leader)
8535 /* All events in a group should have the same clock */
8536 if (group_leader->clock != event->clock)
8540 * Do not allow to attach to a group in a different
8541 * task or CPU context:
8545 * Make sure we're both on the same task, or both
8548 if (group_leader->ctx->task != ctx->task)
8552 * Make sure we're both events for the same CPU;
8553 * grouping events for different CPUs is broken; since
8554 * you can never concurrently schedule them anyhow.
8556 if (group_leader->cpu != event->cpu)
8559 if (group_leader->ctx != ctx)
8564 * Only a group leader can be exclusive or pinned
8566 if (attr.exclusive || attr.pinned)
8571 err = perf_event_set_output(event, output_event);
8576 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
8578 if (IS_ERR(event_file)) {
8579 err = PTR_ERR(event_file);
8585 gctx = group_leader->ctx;
8586 mutex_lock_double(&gctx->mutex, &ctx->mutex);
8588 mutex_lock(&ctx->mutex);
8591 if (!perf_event_validate_size(event)) {
8597 * Must be under the same ctx::mutex as perf_install_in_context(),
8598 * because we need to serialize with concurrent event creation.
8600 if (!exclusive_event_installable(event, ctx)) {
8601 /* exclusive and group stuff are assumed mutually exclusive */
8602 WARN_ON_ONCE(move_group);
8608 WARN_ON_ONCE(ctx->parent_ctx);
8611 * This is the point on no return; we cannot fail hereafter. This is
8612 * where we start modifying current state.
8617 * See perf_event_ctx_lock() for comments on the details
8618 * of swizzling perf_event::ctx.
8620 perf_remove_from_context(group_leader, false);
8622 list_for_each_entry(sibling, &group_leader->sibling_list,
8624 perf_remove_from_context(sibling, false);
8629 * Wait for everybody to stop referencing the events through
8630 * the old lists, before installing it on new lists.
8635 * Install the group siblings before the group leader.
8637 * Because a group leader will try and install the entire group
8638 * (through the sibling list, which is still in-tact), we can
8639 * end up with siblings installed in the wrong context.
8641 * By installing siblings first we NO-OP because they're not
8642 * reachable through the group lists.
8644 list_for_each_entry(sibling, &group_leader->sibling_list,
8646 perf_event__state_init(sibling);
8647 perf_install_in_context(ctx, sibling, sibling->cpu);
8652 * Removing from the context ends up with disabled
8653 * event. What we want here is event in the initial
8654 * startup state, ready to be add into new context.
8656 perf_event__state_init(group_leader);
8657 perf_install_in_context(ctx, group_leader, group_leader->cpu);
8661 * Now that all events are installed in @ctx, nothing
8662 * references @gctx anymore, so drop the last reference we have
8669 * Precalculate sample_data sizes; do while holding ctx::mutex such
8670 * that we're serialized against further additions and before
8671 * perf_install_in_context() which is the point the event is active and
8672 * can use these values.
8674 perf_event__header_size(event);
8675 perf_event__id_header_size(event);
8677 perf_install_in_context(ctx, event, event->cpu);
8678 perf_unpin_context(ctx);
8681 mutex_unlock(&gctx->mutex);
8682 mutex_unlock(&ctx->mutex);
8685 mutex_unlock(&task->signal->cred_guard_mutex);
8686 put_task_struct(task);
8691 event->owner = current;
8693 mutex_lock(¤t->perf_event_mutex);
8694 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
8695 mutex_unlock(¤t->perf_event_mutex);
8698 * Drop the reference on the group_event after placing the
8699 * new event on the sibling_list. This ensures destruction
8700 * of the group leader will find the pointer to itself in
8701 * perf_group_detach().
8704 fd_install(event_fd, event_file);
8709 mutex_unlock(&gctx->mutex);
8710 mutex_unlock(&ctx->mutex);
8714 perf_unpin_context(ctx);
8718 * If event_file is set, the fput() above will have called ->release()
8719 * and that will take care of freeing the event.
8725 mutex_unlock(&task->signal->cred_guard_mutex);
8730 put_task_struct(task);
8734 put_unused_fd(event_fd);
8739 * perf_event_create_kernel_counter
8741 * @attr: attributes of the counter to create
8742 * @cpu: cpu in which the counter is bound
8743 * @task: task to profile (NULL for percpu)
8746 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
8747 struct task_struct *task,
8748 perf_overflow_handler_t overflow_handler,
8751 struct perf_event_context *ctx;
8752 struct perf_event *event;
8756 * Get the target context (task or percpu):
8759 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
8760 overflow_handler, context, -1);
8761 if (IS_ERR(event)) {
8762 err = PTR_ERR(event);
8766 /* Mark owner so we could distinguish it from user events. */
8767 event->owner = EVENT_OWNER_KERNEL;
8769 ctx = find_get_context(event->pmu, task, event);
8775 WARN_ON_ONCE(ctx->parent_ctx);
8776 mutex_lock(&ctx->mutex);
8777 if (!exclusive_event_installable(event, ctx)) {
8778 mutex_unlock(&ctx->mutex);
8779 perf_unpin_context(ctx);
8785 perf_install_in_context(ctx, event, cpu);
8786 perf_unpin_context(ctx);
8787 mutex_unlock(&ctx->mutex);
8794 return ERR_PTR(err);
8796 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
8798 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
8800 struct perf_event_context *src_ctx;
8801 struct perf_event_context *dst_ctx;
8802 struct perf_event *event, *tmp;
8805 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
8806 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
8809 * See perf_event_ctx_lock() for comments on the details
8810 * of swizzling perf_event::ctx.
8812 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
8813 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
8815 perf_remove_from_context(event, false);
8816 unaccount_event_cpu(event, src_cpu);
8818 list_add(&event->migrate_entry, &events);
8822 * Wait for the events to quiesce before re-instating them.
8827 * Re-instate events in 2 passes.
8829 * Skip over group leaders and only install siblings on this first
8830 * pass, siblings will not get enabled without a leader, however a
8831 * leader will enable its siblings, even if those are still on the old
8834 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8835 if (event->group_leader == event)
8838 list_del(&event->migrate_entry);
8839 if (event->state >= PERF_EVENT_STATE_OFF)
8840 event->state = PERF_EVENT_STATE_INACTIVE;
8841 account_event_cpu(event, dst_cpu);
8842 perf_install_in_context(dst_ctx, event, dst_cpu);
8847 * Once all the siblings are setup properly, install the group leaders
8850 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
8851 list_del(&event->migrate_entry);
8852 if (event->state >= PERF_EVENT_STATE_OFF)
8853 event->state = PERF_EVENT_STATE_INACTIVE;
8854 account_event_cpu(event, dst_cpu);
8855 perf_install_in_context(dst_ctx, event, dst_cpu);
8858 mutex_unlock(&dst_ctx->mutex);
8859 mutex_unlock(&src_ctx->mutex);
8861 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
8863 static void sync_child_event(struct perf_event *child_event,
8864 struct task_struct *child)
8866 struct perf_event *parent_event = child_event->parent;
8869 if (child_event->attr.inherit_stat)
8870 perf_event_read_event(child_event, child);
8872 child_val = perf_event_count(child_event);
8875 * Add back the child's count to the parent's count:
8877 atomic64_add(child_val, &parent_event->child_count);
8878 atomic64_add(child_event->total_time_enabled,
8879 &parent_event->child_total_time_enabled);
8880 atomic64_add(child_event->total_time_running,
8881 &parent_event->child_total_time_running);
8884 * Remove this event from the parent's list
8886 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
8887 mutex_lock(&parent_event->child_mutex);
8888 list_del_init(&child_event->child_list);
8889 mutex_unlock(&parent_event->child_mutex);
8892 * Make sure user/parent get notified, that we just
8895 perf_event_wakeup(parent_event);
8898 * Release the parent event, if this was the last
8901 put_event(parent_event);
8905 __perf_event_exit_task(struct perf_event *child_event,
8906 struct perf_event_context *child_ctx,
8907 struct task_struct *child)
8910 * Do not destroy the 'original' grouping; because of the context
8911 * switch optimization the original events could've ended up in a
8912 * random child task.
8914 * If we were to destroy the original group, all group related
8915 * operations would cease to function properly after this random
8918 * Do destroy all inherited groups, we don't care about those
8919 * and being thorough is better.
8921 perf_remove_from_context(child_event, !!child_event->parent);
8924 * It can happen that the parent exits first, and has events
8925 * that are still around due to the child reference. These
8926 * events need to be zapped.
8928 if (child_event->parent) {
8929 sync_child_event(child_event, child);
8930 free_event(child_event);
8932 child_event->state = PERF_EVENT_STATE_EXIT;
8933 perf_event_wakeup(child_event);
8937 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
8939 struct perf_event *child_event, *next;
8940 struct perf_event_context *child_ctx, *clone_ctx = NULL;
8941 unsigned long flags;
8943 if (likely(!child->perf_event_ctxp[ctxn]))
8946 local_irq_save(flags);
8948 * We can't reschedule here because interrupts are disabled,
8949 * and either child is current or it is a task that can't be
8950 * scheduled, so we are now safe from rescheduling changing
8953 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
8956 * Take the context lock here so that if find_get_context is
8957 * reading child->perf_event_ctxp, we wait until it has
8958 * incremented the context's refcount before we do put_ctx below.
8960 raw_spin_lock(&child_ctx->lock);
8961 task_ctx_sched_out(child_ctx);
8962 child->perf_event_ctxp[ctxn] = NULL;
8965 * If this context is a clone; unclone it so it can't get
8966 * swapped to another process while we're removing all
8967 * the events from it.
8969 clone_ctx = unclone_ctx(child_ctx);
8970 update_context_time(child_ctx);
8971 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
8977 * Report the task dead after unscheduling the events so that we
8978 * won't get any samples after PERF_RECORD_EXIT. We can however still
8979 * get a few PERF_RECORD_READ events.
8981 perf_event_task(child, child_ctx, 0);
8984 * We can recurse on the same lock type through:
8986 * __perf_event_exit_task()
8987 * sync_child_event()
8989 * mutex_lock(&ctx->mutex)
8991 * But since its the parent context it won't be the same instance.
8993 mutex_lock(&child_ctx->mutex);
8995 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
8996 __perf_event_exit_task(child_event, child_ctx, child);
8998 mutex_unlock(&child_ctx->mutex);
9004 * When a child task exits, feed back event values to parent events.
9006 * Can be called with cred_guard_mutex held when called from
9007 * install_exec_creds().
9009 void perf_event_exit_task(struct task_struct *child)
9011 struct perf_event *event, *tmp;
9014 mutex_lock(&child->perf_event_mutex);
9015 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
9017 list_del_init(&event->owner_entry);
9020 * Ensure the list deletion is visible before we clear
9021 * the owner, closes a race against perf_release() where
9022 * we need to serialize on the owner->perf_event_mutex.
9025 event->owner = NULL;
9027 mutex_unlock(&child->perf_event_mutex);
9029 for_each_task_context_nr(ctxn)
9030 perf_event_exit_task_context(child, ctxn);
9033 * The perf_event_exit_task_context calls perf_event_task
9034 * with child's task_ctx, which generates EXIT events for
9035 * child contexts and sets child->perf_event_ctxp[] to NULL.
9036 * At this point we need to send EXIT events to cpu contexts.
9038 perf_event_task(child, NULL, 0);
9041 static void perf_free_event(struct perf_event *event,
9042 struct perf_event_context *ctx)
9044 struct perf_event *parent = event->parent;
9046 if (WARN_ON_ONCE(!parent))
9049 mutex_lock(&parent->child_mutex);
9050 list_del_init(&event->child_list);
9051 mutex_unlock(&parent->child_mutex);
9055 raw_spin_lock_irq(&ctx->lock);
9056 perf_group_detach(event);
9057 list_del_event(event, ctx);
9058 raw_spin_unlock_irq(&ctx->lock);
9063 * Free an unexposed, unused context as created by inheritance by
9064 * perf_event_init_task below, used by fork() in case of fail.
9066 * Not all locks are strictly required, but take them anyway to be nice and
9067 * help out with the lockdep assertions.
9069 void perf_event_free_task(struct task_struct *task)
9071 struct perf_event_context *ctx;
9072 struct perf_event *event, *tmp;
9075 for_each_task_context_nr(ctxn) {
9076 ctx = task->perf_event_ctxp[ctxn];
9080 mutex_lock(&ctx->mutex);
9082 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
9084 perf_free_event(event, ctx);
9086 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
9088 perf_free_event(event, ctx);
9090 if (!list_empty(&ctx->pinned_groups) ||
9091 !list_empty(&ctx->flexible_groups))
9094 mutex_unlock(&ctx->mutex);
9100 void perf_event_delayed_put(struct task_struct *task)
9104 for_each_task_context_nr(ctxn)
9105 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
9108 struct perf_event *perf_event_get(unsigned int fd)
9112 struct perf_event *event;
9114 err = perf_fget_light(fd, &f);
9116 return ERR_PTR(err);
9118 event = f.file->private_data;
9119 atomic_long_inc(&event->refcount);
9125 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
9128 return ERR_PTR(-EINVAL);
9130 return &event->attr;
9134 * inherit a event from parent task to child task:
9136 static struct perf_event *
9137 inherit_event(struct perf_event *parent_event,
9138 struct task_struct *parent,
9139 struct perf_event_context *parent_ctx,
9140 struct task_struct *child,
9141 struct perf_event *group_leader,
9142 struct perf_event_context *child_ctx)
9144 enum perf_event_active_state parent_state = parent_event->state;
9145 struct perf_event *child_event;
9146 unsigned long flags;
9149 * Instead of creating recursive hierarchies of events,
9150 * we link inherited events back to the original parent,
9151 * which has a filp for sure, which we use as the reference
9154 if (parent_event->parent)
9155 parent_event = parent_event->parent;
9157 child_event = perf_event_alloc(&parent_event->attr,
9160 group_leader, parent_event,
9162 if (IS_ERR(child_event))
9165 if (is_orphaned_event(parent_event) ||
9166 !atomic_long_inc_not_zero(&parent_event->refcount)) {
9167 free_event(child_event);
9174 * Make the child state follow the state of the parent event,
9175 * not its attr.disabled bit. We hold the parent's mutex,
9176 * so we won't race with perf_event_{en, dis}able_family.
9178 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
9179 child_event->state = PERF_EVENT_STATE_INACTIVE;
9181 child_event->state = PERF_EVENT_STATE_OFF;
9183 if (parent_event->attr.freq) {
9184 u64 sample_period = parent_event->hw.sample_period;
9185 struct hw_perf_event *hwc = &child_event->hw;
9187 hwc->sample_period = sample_period;
9188 hwc->last_period = sample_period;
9190 local64_set(&hwc->period_left, sample_period);
9193 child_event->ctx = child_ctx;
9194 child_event->overflow_handler = parent_event->overflow_handler;
9195 child_event->overflow_handler_context
9196 = parent_event->overflow_handler_context;
9199 * Precalculate sample_data sizes
9201 perf_event__header_size(child_event);
9202 perf_event__id_header_size(child_event);
9205 * Link it up in the child's context:
9207 raw_spin_lock_irqsave(&child_ctx->lock, flags);
9208 add_event_to_ctx(child_event, child_ctx);
9209 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
9212 * Link this into the parent event's child list
9214 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
9215 mutex_lock(&parent_event->child_mutex);
9216 list_add_tail(&child_event->child_list, &parent_event->child_list);
9217 mutex_unlock(&parent_event->child_mutex);
9222 static int inherit_group(struct perf_event *parent_event,
9223 struct task_struct *parent,
9224 struct perf_event_context *parent_ctx,
9225 struct task_struct *child,
9226 struct perf_event_context *child_ctx)
9228 struct perf_event *leader;
9229 struct perf_event *sub;
9230 struct perf_event *child_ctr;
9232 leader = inherit_event(parent_event, parent, parent_ctx,
9233 child, NULL, child_ctx);
9235 return PTR_ERR(leader);
9236 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
9237 child_ctr = inherit_event(sub, parent, parent_ctx,
9238 child, leader, child_ctx);
9239 if (IS_ERR(child_ctr))
9240 return PTR_ERR(child_ctr);
9246 inherit_task_group(struct perf_event *event, struct task_struct *parent,
9247 struct perf_event_context *parent_ctx,
9248 struct task_struct *child, int ctxn,
9252 struct perf_event_context *child_ctx;
9254 if (!event->attr.inherit) {
9259 child_ctx = child->perf_event_ctxp[ctxn];
9262 * This is executed from the parent task context, so
9263 * inherit events that have been marked for cloning.
9264 * First allocate and initialize a context for the
9268 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
9272 child->perf_event_ctxp[ctxn] = child_ctx;
9275 ret = inherit_group(event, parent, parent_ctx,
9285 * Initialize the perf_event context in task_struct
9287 static int perf_event_init_context(struct task_struct *child, int ctxn)
9289 struct perf_event_context *child_ctx, *parent_ctx;
9290 struct perf_event_context *cloned_ctx;
9291 struct perf_event *event;
9292 struct task_struct *parent = current;
9293 int inherited_all = 1;
9294 unsigned long flags;
9297 if (likely(!parent->perf_event_ctxp[ctxn]))
9301 * If the parent's context is a clone, pin it so it won't get
9304 parent_ctx = perf_pin_task_context(parent, ctxn);
9309 * No need to check if parent_ctx != NULL here; since we saw
9310 * it non-NULL earlier, the only reason for it to become NULL
9311 * is if we exit, and since we're currently in the middle of
9312 * a fork we can't be exiting at the same time.
9316 * Lock the parent list. No need to lock the child - not PID
9317 * hashed yet and not running, so nobody can access it.
9319 mutex_lock(&parent_ctx->mutex);
9322 * We dont have to disable NMIs - we are only looking at
9323 * the list, not manipulating it:
9325 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
9326 ret = inherit_task_group(event, parent, parent_ctx,
9327 child, ctxn, &inherited_all);
9333 * We can't hold ctx->lock when iterating the ->flexible_group list due
9334 * to allocations, but we need to prevent rotation because
9335 * rotate_ctx() will change the list from interrupt context.
9337 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9338 parent_ctx->rotate_disable = 1;
9339 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9341 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
9342 ret = inherit_task_group(event, parent, parent_ctx,
9343 child, ctxn, &inherited_all);
9348 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
9349 parent_ctx->rotate_disable = 0;
9351 child_ctx = child->perf_event_ctxp[ctxn];
9353 if (child_ctx && inherited_all) {
9355 * Mark the child context as a clone of the parent
9356 * context, or of whatever the parent is a clone of.
9358 * Note that if the parent is a clone, the holding of
9359 * parent_ctx->lock avoids it from being uncloned.
9361 cloned_ctx = parent_ctx->parent_ctx;
9363 child_ctx->parent_ctx = cloned_ctx;
9364 child_ctx->parent_gen = parent_ctx->parent_gen;
9366 child_ctx->parent_ctx = parent_ctx;
9367 child_ctx->parent_gen = parent_ctx->generation;
9369 get_ctx(child_ctx->parent_ctx);
9372 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
9373 mutex_unlock(&parent_ctx->mutex);
9375 perf_unpin_context(parent_ctx);
9376 put_ctx(parent_ctx);
9382 * Initialize the perf_event context in task_struct
9384 int perf_event_init_task(struct task_struct *child)
9388 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
9389 mutex_init(&child->perf_event_mutex);
9390 INIT_LIST_HEAD(&child->perf_event_list);
9392 for_each_task_context_nr(ctxn) {
9393 ret = perf_event_init_context(child, ctxn);
9395 perf_event_free_task(child);
9403 static void __init perf_event_init_all_cpus(void)
9405 struct swevent_htable *swhash;
9408 for_each_possible_cpu(cpu) {
9409 swhash = &per_cpu(swevent_htable, cpu);
9410 mutex_init(&swhash->hlist_mutex);
9411 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
9415 static void perf_event_init_cpu(int cpu)
9417 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9419 mutex_lock(&swhash->hlist_mutex);
9420 if (swhash->hlist_refcount > 0) {
9421 struct swevent_hlist *hlist;
9423 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
9425 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9427 mutex_unlock(&swhash->hlist_mutex);
9430 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
9431 static void __perf_event_exit_context(void *__info)
9433 struct remove_event re = { .detach_group = true };
9434 struct perf_event_context *ctx = __info;
9437 list_for_each_entry_rcu(re.event, &ctx->event_list, event_entry)
9438 __perf_remove_from_context(&re);
9442 static void perf_event_exit_cpu_context(int cpu)
9444 struct perf_event_context *ctx;
9448 idx = srcu_read_lock(&pmus_srcu);
9449 list_for_each_entry_rcu(pmu, &pmus, entry) {
9450 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
9452 mutex_lock(&ctx->mutex);
9453 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
9454 mutex_unlock(&ctx->mutex);
9456 srcu_read_unlock(&pmus_srcu, idx);
9459 static void perf_event_exit_cpu(int cpu)
9461 perf_event_exit_cpu_context(cpu);
9464 static inline void perf_event_exit_cpu(int cpu) { }
9468 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
9472 for_each_online_cpu(cpu)
9473 perf_event_exit_cpu(cpu);
9479 * Run the perf reboot notifier at the very last possible moment so that
9480 * the generic watchdog code runs as long as possible.
9482 static struct notifier_block perf_reboot_notifier = {
9483 .notifier_call = perf_reboot,
9484 .priority = INT_MIN,
9488 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
9490 unsigned int cpu = (long)hcpu;
9492 switch (action & ~CPU_TASKS_FROZEN) {
9494 case CPU_UP_PREPARE:
9495 case CPU_DOWN_FAILED:
9496 perf_event_init_cpu(cpu);
9499 case CPU_UP_CANCELED:
9500 case CPU_DOWN_PREPARE:
9501 perf_event_exit_cpu(cpu);
9510 void __init perf_event_init(void)
9516 perf_event_init_all_cpus();
9517 init_srcu_struct(&pmus_srcu);
9518 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
9519 perf_pmu_register(&perf_cpu_clock, NULL, -1);
9520 perf_pmu_register(&perf_task_clock, NULL, -1);
9522 perf_cpu_notifier(perf_cpu_notify);
9523 register_reboot_notifier(&perf_reboot_notifier);
9525 ret = init_hw_breakpoint();
9526 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
9528 /* do not patch jump label more than once per second */
9529 jump_label_rate_limit(&perf_sched_events, HZ);
9532 * Build time assertion that we keep the data_head at the intended
9533 * location. IOW, validation we got the __reserved[] size right.
9535 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
9539 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
9542 struct perf_pmu_events_attr *pmu_attr =
9543 container_of(attr, struct perf_pmu_events_attr, attr);
9545 if (pmu_attr->event_str)
9546 return sprintf(page, "%s\n", pmu_attr->event_str);
9551 static int __init perf_event_sysfs_init(void)
9556 mutex_lock(&pmus_lock);
9558 ret = bus_register(&pmu_bus);
9562 list_for_each_entry(pmu, &pmus, entry) {
9563 if (!pmu->name || pmu->type < 0)
9566 ret = pmu_dev_alloc(pmu);
9567 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
9569 pmu_bus_running = 1;
9573 mutex_unlock(&pmus_lock);
9577 device_initcall(perf_event_sysfs_init);
9579 #ifdef CONFIG_CGROUP_PERF
9580 static struct cgroup_subsys_state *
9581 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
9583 struct perf_cgroup *jc;
9585 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
9587 return ERR_PTR(-ENOMEM);
9589 jc->info = alloc_percpu(struct perf_cgroup_info);
9592 return ERR_PTR(-ENOMEM);
9598 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
9600 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
9602 free_percpu(jc->info);
9606 static int __perf_cgroup_move(void *info)
9608 struct task_struct *task = info;
9610 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
9615 static void perf_cgroup_attach(struct cgroup_taskset *tset)
9617 struct task_struct *task;
9618 struct cgroup_subsys_state *css;
9620 cgroup_taskset_for_each(task, css, tset)
9621 task_function_call(task, __perf_cgroup_move, task);
9624 struct cgroup_subsys perf_event_cgrp_subsys = {
9625 .css_alloc = perf_cgroup_css_alloc,
9626 .css_free = perf_cgroup_css_free,
9627 .attach = perf_cgroup_attach,
9629 #endif /* CONFIG_CGROUP_PERF */