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1 | /* |
2 | * Performance events core code: |
3 | * |
4 | * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> |
5 | * Copyright (C) 2008-2009 Red Hat, Inc., Ingo Molnar |
6 | * Copyright (C) 2008-2009 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> |
7 | * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> |
8 | * |
9 | * For licensing details see kernel-base/COPYING |
10 | */ |
11 | |
12 | #include <linux/fs.h> |
13 | #include <linux/mm.h> |
14 | #include <linux/cpu.h> |
15 | #include <linux/smp.h> |
16 | #include <linux/file.h> |
17 | #include <linux/poll.h> |
18 | #include <linux/slab.h> |
19 | #include <linux/sysfs.h> |
20 | #include <linux/dcache.h> |
21 | #include <linux/percpu.h> |
22 | #include <linux/ptrace.h> |
23 | #include <linux/vmstat.h> |
24 | #include <linux/vmalloc.h> |
25 | #include <linux/hardirq.h> |
26 | #include <linux/rculist.h> |
27 | #include <linux/uaccess.h> |
28 | #include <linux/syscalls.h> |
29 | #include <linux/anon_inodes.h> |
30 | #include <linux/kernel_stat.h> |
31 | #include <linux/perf_event.h> |
32 | #include <linux/ftrace_event.h> |
33 | #include <linux/hw_breakpoint.h> |
34 | |
35 | #include <asm/irq_regs.h> |
36 | |
37 | /* |
38 | * Each CPU has a list of per CPU events: |
39 | */ |
40 | static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context); |
41 | |
42 | int perf_max_events __read_mostly = 1; |
43 | static int perf_reserved_percpu __read_mostly; |
44 | static int perf_overcommit __read_mostly = 1; |
45 | |
46 | static atomic_t nr_events __read_mostly; |
47 | static atomic_t nr_mmap_events __read_mostly; |
48 | static atomic_t nr_comm_events __read_mostly; |
49 | static atomic_t nr_task_events __read_mostly; |
50 | |
51 | /* |
52 | * perf event paranoia level: |
53 | * -1 - not paranoid at all |
54 | * 0 - disallow raw tracepoint access for unpriv |
55 | * 1 - disallow cpu events for unpriv |
56 | * 2 - disallow kernel profiling for unpriv |
57 | */ |
58 | int sysctl_perf_event_paranoid __read_mostly = 1; |
59 | |
60 | int sysctl_perf_event_mlock __read_mostly = 512; /* 'free' kb per user */ |
61 | |
62 | /* |
63 | * max perf event sample rate |
64 | */ |
65 | int sysctl_perf_event_sample_rate __read_mostly = 100000; |
66 | |
67 | static atomic64_t perf_event_id; |
68 | |
69 | /* |
70 | * Lock for (sysadmin-configurable) event reservations: |
71 | */ |
72 | static DEFINE_SPINLOCK(perf_resource_lock); |
73 | |
74 | /* |
75 | * Architecture provided APIs - weak aliases: |
76 | */ |
77 | extern __weak const struct pmu *hw_perf_event_init(struct perf_event *event) |
78 | { |
79 | return NULL; |
80 | } |
81 | |
82 | void __weak hw_perf_disable(void) { barrier(); } |
83 | void __weak hw_perf_enable(void) { barrier(); } |
84 | |
85 | int __weak |
86 | hw_perf_group_sched_in(struct perf_event *group_leader, |
87 | struct perf_cpu_context *cpuctx, |
88 | struct perf_event_context *ctx) |
89 | { |
90 | return 0; |
91 | } |
92 | |
93 | void __weak perf_event_print_debug(void) { } |
94 | |
95 | static DEFINE_PER_CPU(int, perf_disable_count); |
96 | |
97 | void perf_disable(void) |
98 | { |
99 | if (!__get_cpu_var(perf_disable_count)++) |
100 | hw_perf_disable(); |
101 | } |
102 | |
103 | void perf_enable(void) |
104 | { |
105 | if (!--__get_cpu_var(perf_disable_count)) |
106 | hw_perf_enable(); |
107 | } |
108 | |
109 | static void get_ctx(struct perf_event_context *ctx) |
110 | { |
111 | WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); |
112 | } |
113 | |
114 | static void free_ctx(struct rcu_head *head) |
115 | { |
116 | struct perf_event_context *ctx; |
117 | |
118 | ctx = container_of(head, struct perf_event_context, rcu_head); |
119 | kfree(ctx); |
120 | } |
121 | |
122 | static void put_ctx(struct perf_event_context *ctx) |
123 | { |
124 | if (atomic_dec_and_test(&ctx->refcount)) { |
125 | if (ctx->parent_ctx) |
126 | put_ctx(ctx->parent_ctx); |
127 | if (ctx->task) |
128 | put_task_struct(ctx->task); |
129 | call_rcu(&ctx->rcu_head, free_ctx); |
130 | } |
131 | } |
132 | |
133 | static void unclone_ctx(struct perf_event_context *ctx) |
134 | { |
135 | if (ctx->parent_ctx) { |
136 | put_ctx(ctx->parent_ctx); |
137 | ctx->parent_ctx = NULL; |
138 | } |
139 | } |
140 | |
141 | /* |
142 | * If we inherit events we want to return the parent event id |
143 | * to userspace. |
144 | */ |
145 | static u64 primary_event_id(struct perf_event *event) |
146 | { |
147 | u64 id = event->id; |
148 | |
149 | if (event->parent) |
150 | id = event->parent->id; |
151 | |
152 | return id; |
153 | } |
154 | |
155 | /* |
156 | * Get the perf_event_context for a task and lock it. |
157 | * This has to cope with with the fact that until it is locked, |
158 | * the context could get moved to another task. |
159 | */ |
160 | static struct perf_event_context * |
161 | perf_lock_task_context(struct task_struct *task, unsigned long *flags) |
162 | { |
163 | struct perf_event_context *ctx; |
164 | |
165 | rcu_read_lock(); |
166 | retry: |
167 | ctx = rcu_dereference(task->perf_event_ctxp); |
168 | if (ctx) { |
169 | /* |
170 | * If this context is a clone of another, it might |
171 | * get swapped for another underneath us by |
172 | * perf_event_task_sched_out, though the |
173 | * rcu_read_lock() protects us from any context |
174 | * getting freed. Lock the context and check if it |
175 | * got swapped before we could get the lock, and retry |
176 | * if so. If we locked the right context, then it |
177 | * can't get swapped on us any more. |
178 | */ |
179 | raw_spin_lock_irqsave(&ctx->lock, *flags); |
180 | if (ctx != rcu_dereference(task->perf_event_ctxp)) { |
181 | raw_spin_unlock_irqrestore(&ctx->lock, *flags); |
182 | goto retry; |
183 | } |
184 | |
185 | if (!atomic_inc_not_zero(&ctx->refcount)) { |
186 | raw_spin_unlock_irqrestore(&ctx->lock, *flags); |
187 | ctx = NULL; |
188 | } |
189 | } |
190 | rcu_read_unlock(); |
191 | return ctx; |
192 | } |
193 | |
194 | /* |
195 | * Get the context for a task and increment its pin_count so it |
196 | * can't get swapped to another task. This also increments its |
197 | * reference count so that the context can't get freed. |
198 | */ |
199 | static struct perf_event_context *perf_pin_task_context(struct task_struct *task) |
200 | { |
201 | struct perf_event_context *ctx; |
202 | unsigned long flags; |
203 | |
204 | ctx = perf_lock_task_context(task, &flags); |
205 | if (ctx) { |
206 | ++ctx->pin_count; |
207 | raw_spin_unlock_irqrestore(&ctx->lock, flags); |
208 | } |
209 | return ctx; |
210 | } |
211 | |
212 | static void perf_unpin_context(struct perf_event_context *ctx) |
213 | { |
214 | unsigned long flags; |
215 | |
216 | raw_spin_lock_irqsave(&ctx->lock, flags); |
217 | --ctx->pin_count; |
218 | raw_spin_unlock_irqrestore(&ctx->lock, flags); |
219 | put_ctx(ctx); |
220 | } |
221 | |
222 | static inline u64 perf_clock(void) |
223 | { |
224 | return cpu_clock(raw_smp_processor_id()); |
225 | } |
226 | |
227 | /* |
228 | * Update the record of the current time in a context. |
229 | */ |
230 | static void update_context_time(struct perf_event_context *ctx) |
231 | { |
232 | u64 now = perf_clock(); |
233 | |
234 | ctx->time += now - ctx->timestamp; |
235 | ctx->timestamp = now; |
236 | } |
237 | |
238 | /* |
239 | * Update the total_time_enabled and total_time_running fields for a event. |
240 | */ |
241 | static void update_event_times(struct perf_event *event) |
242 | { |
243 | struct perf_event_context *ctx = event->ctx; |
244 | u64 run_end; |
245 | |
246 | if (event->state < PERF_EVENT_STATE_INACTIVE || |
247 | event->group_leader->state < PERF_EVENT_STATE_INACTIVE) |
248 | return; |
249 | |
250 | if (ctx->is_active) |
251 | run_end = ctx->time; |
252 | else |
253 | run_end = event->tstamp_stopped; |
254 | |
255 | event->total_time_enabled = run_end - event->tstamp_enabled; |
256 | |
257 | if (event->state == PERF_EVENT_STATE_INACTIVE) |
258 | run_end = event->tstamp_stopped; |
259 | else |
260 | run_end = ctx->time; |
261 | |
262 | event->total_time_running = run_end - event->tstamp_running; |
263 | } |
264 | |
265 | static struct list_head * |
266 | ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) |
267 | { |
268 | if (event->attr.pinned) |
269 | return &ctx->pinned_groups; |
270 | else |
271 | return &ctx->flexible_groups; |
272 | } |
273 | |
274 | /* |
275 | * Add a event from the lists for its context. |
276 | * Must be called with ctx->mutex and ctx->lock held. |
277 | */ |
278 | static void |
279 | list_add_event(struct perf_event *event, struct perf_event_context *ctx) |
280 | { |
281 | struct perf_event *group_leader = event->group_leader; |
282 | |
283 | /* |
284 | * Depending on whether it is a standalone or sibling event, |
285 | * add it straight to the context's event list, or to the group |
286 | * leader's sibling list: |
287 | */ |
288 | if (group_leader == event) { |
289 | struct list_head *list; |
290 | |
291 | if (is_software_event(event)) |
292 | event->group_flags |= PERF_GROUP_SOFTWARE; |
293 | |
294 | list = ctx_group_list(event, ctx); |
295 | list_add_tail(&event->group_entry, list); |
296 | } else { |
297 | if (group_leader->group_flags & PERF_GROUP_SOFTWARE && |
298 | !is_software_event(event)) |
299 | group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; |
300 | |
301 | list_add_tail(&event->group_entry, &group_leader->sibling_list); |
302 | group_leader->nr_siblings++; |
303 | } |
304 | |
305 | list_add_rcu(&event->event_entry, &ctx->event_list); |
306 | ctx->nr_events++; |
307 | if (event->attr.inherit_stat) |
308 | ctx->nr_stat++; |
309 | } |
310 | |
311 | /* |
312 | * Remove a event from the lists for its context. |
313 | * Must be called with ctx->mutex and ctx->lock held. |
314 | */ |
315 | static void |
316 | list_del_event(struct perf_event *event, struct perf_event_context *ctx) |
317 | { |
318 | struct perf_event *sibling, *tmp; |
319 | |
320 | if (list_empty(&event->group_entry)) |
321 | return; |
322 | ctx->nr_events--; |
323 | if (event->attr.inherit_stat) |
324 | ctx->nr_stat--; |
325 | |
326 | list_del_init(&event->group_entry); |
327 | list_del_rcu(&event->event_entry); |
328 | |
329 | if (event->group_leader != event) |
330 | event->group_leader->nr_siblings--; |
331 | |
332 | update_event_times(event); |
333 | |
334 | /* |
335 | * If event was in error state, then keep it |
336 | * that way, otherwise bogus counts will be |
337 | * returned on read(). The only way to get out |
338 | * of error state is by explicit re-enabling |
339 | * of the event |
340 | */ |
341 | if (event->state > PERF_EVENT_STATE_OFF) |
342 | event->state = PERF_EVENT_STATE_OFF; |
343 | |
344 | /* |
345 | * If this was a group event with sibling events then |
346 | * upgrade the siblings to singleton events by adding them |
347 | * to the context list directly: |
348 | */ |
349 | list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { |
350 | struct list_head *list; |
351 | |
352 | list = ctx_group_list(event, ctx); |
353 | list_move_tail(&sibling->group_entry, list); |
354 | sibling->group_leader = sibling; |
355 | |
356 | /* Inherit group flags from the previous leader */ |
357 | sibling->group_flags = event->group_flags; |
358 | } |
359 | } |
360 | |
361 | static void |
362 | event_sched_out(struct perf_event *event, |
363 | struct perf_cpu_context *cpuctx, |
364 | struct perf_event_context *ctx) |
365 | { |
366 | if (event->state != PERF_EVENT_STATE_ACTIVE) |
367 | return; |
368 | |
369 | event->state = PERF_EVENT_STATE_INACTIVE; |
370 | if (event->pending_disable) { |
371 | event->pending_disable = 0; |
372 | event->state = PERF_EVENT_STATE_OFF; |
373 | } |
374 | event->tstamp_stopped = ctx->time; |
375 | event->pmu->disable(event); |
376 | event->oncpu = -1; |
377 | |
378 | if (!is_software_event(event)) |
379 | cpuctx->active_oncpu--; |
380 | ctx->nr_active--; |
381 | if (event->attr.exclusive || !cpuctx->active_oncpu) |
382 | cpuctx->exclusive = 0; |
383 | } |
384 | |
385 | static void |
386 | group_sched_out(struct perf_event *group_event, |
387 | struct perf_cpu_context *cpuctx, |
388 | struct perf_event_context *ctx) |
389 | { |
390 | struct perf_event *event; |
391 | |
392 | if (group_event->state != PERF_EVENT_STATE_ACTIVE) |
393 | return; |
394 | |
395 | event_sched_out(group_event, cpuctx, ctx); |
396 | |
397 | /* |
398 | * Schedule out siblings (if any): |
399 | */ |
400 | list_for_each_entry(event, &group_event->sibling_list, group_entry) |
401 | event_sched_out(event, cpuctx, ctx); |
402 | |
403 | if (group_event->attr.exclusive) |
404 | cpuctx->exclusive = 0; |
405 | } |
406 | |
407 | /* |
408 | * Cross CPU call to remove a performance event |
409 | * |
410 | * We disable the event on the hardware level first. After that we |
411 | * remove it from the context list. |
412 | */ |
413 | static void __perf_event_remove_from_context(void *info) |
414 | { |
415 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
416 | struct perf_event *event = info; |
417 | struct perf_event_context *ctx = event->ctx; |
418 | |
419 | /* |
420 | * If this is a task context, we need to check whether it is |
421 | * the current task context of this cpu. If not it has been |
422 | * scheduled out before the smp call arrived. |
423 | */ |
424 | if (ctx->task && cpuctx->task_ctx != ctx) |
425 | return; |
426 | |
427 | raw_spin_lock(&ctx->lock); |
428 | /* |
429 | * Protect the list operation against NMI by disabling the |
430 | * events on a global level. |
431 | */ |
432 | perf_disable(); |
433 | |
434 | event_sched_out(event, cpuctx, ctx); |
435 | |
436 | list_del_event(event, ctx); |
437 | |
438 | if (!ctx->task) { |
439 | /* |
440 | * Allow more per task events with respect to the |
441 | * reservation: |
442 | */ |
443 | cpuctx->max_pertask = |
444 | min(perf_max_events - ctx->nr_events, |
445 | perf_max_events - perf_reserved_percpu); |
446 | } |
447 | |
448 | perf_enable(); |
449 | raw_spin_unlock(&ctx->lock); |
450 | } |
451 | |
452 | |
453 | /* |
454 | * Remove the event from a task's (or a CPU's) list of events. |
455 | * |
456 | * Must be called with ctx->mutex held. |
457 | * |
458 | * CPU events are removed with a smp call. For task events we only |
459 | * call when the task is on a CPU. |
460 | * |
461 | * If event->ctx is a cloned context, callers must make sure that |
462 | * every task struct that event->ctx->task could possibly point to |
463 | * remains valid. This is OK when called from perf_release since |
464 | * that only calls us on the top-level context, which can't be a clone. |
465 | * When called from perf_event_exit_task, it's OK because the |
466 | * context has been detached from its task. |
467 | */ |
468 | static void perf_event_remove_from_context(struct perf_event *event) |
469 | { |
470 | struct perf_event_context *ctx = event->ctx; |
471 | struct task_struct *task = ctx->task; |
472 | |
473 | if (!task) { |
474 | /* |
475 | * Per cpu events are removed via an smp call and |
476 | * the removal is always successful. |
477 | */ |
478 | smp_call_function_single(event->cpu, |
479 | __perf_event_remove_from_context, |
480 | event, 1); |
481 | return; |
482 | } |
483 | |
484 | retry: |
485 | task_oncpu_function_call(task, __perf_event_remove_from_context, |
486 | event); |
487 | |
488 | raw_spin_lock_irq(&ctx->lock); |
489 | /* |
490 | * If the context is active we need to retry the smp call. |
491 | */ |
492 | if (ctx->nr_active && !list_empty(&event->group_entry)) { |
493 | raw_spin_unlock_irq(&ctx->lock); |
494 | goto retry; |
495 | } |
496 | |
497 | /* |
498 | * The lock prevents that this context is scheduled in so we |
499 | * can remove the event safely, if the call above did not |
500 | * succeed. |
501 | */ |
502 | if (!list_empty(&event->group_entry)) |
503 | list_del_event(event, ctx); |
504 | raw_spin_unlock_irq(&ctx->lock); |
505 | } |
506 | |
507 | /* |
508 | * Update total_time_enabled and total_time_running for all events in a group. |
509 | */ |
510 | static void update_group_times(struct perf_event *leader) |
511 | { |
512 | struct perf_event *event; |
513 | |
514 | update_event_times(leader); |
515 | list_for_each_entry(event, &leader->sibling_list, group_entry) |
516 | update_event_times(event); |
517 | } |
518 | |
519 | /* |
520 | * Cross CPU call to disable a performance event |
521 | */ |
522 | static void __perf_event_disable(void *info) |
523 | { |
524 | struct perf_event *event = info; |
525 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
526 | struct perf_event_context *ctx = event->ctx; |
527 | |
528 | /* |
529 | * If this is a per-task event, need to check whether this |
530 | * event's task is the current task on this cpu. |
531 | */ |
532 | if (ctx->task && cpuctx->task_ctx != ctx) |
533 | return; |
534 | |
535 | raw_spin_lock(&ctx->lock); |
536 | |
537 | /* |
538 | * If the event is on, turn it off. |
539 | * If it is in error state, leave it in error state. |
540 | */ |
541 | if (event->state >= PERF_EVENT_STATE_INACTIVE) { |
542 | update_context_time(ctx); |
543 | update_group_times(event); |
544 | if (event == event->group_leader) |
545 | group_sched_out(event, cpuctx, ctx); |
546 | else |
547 | event_sched_out(event, cpuctx, ctx); |
548 | event->state = PERF_EVENT_STATE_OFF; |
549 | } |
550 | |
551 | raw_spin_unlock(&ctx->lock); |
552 | } |
553 | |
554 | /* |
555 | * Disable a event. |
556 | * |
557 | * If event->ctx is a cloned context, callers must make sure that |
558 | * every task struct that event->ctx->task could possibly point to |
559 | * remains valid. This condition is satisifed when called through |
560 | * perf_event_for_each_child or perf_event_for_each because they |
561 | * hold the top-level event's child_mutex, so any descendant that |
562 | * goes to exit will block in sync_child_event. |
563 | * When called from perf_pending_event it's OK because event->ctx |
564 | * is the current context on this CPU and preemption is disabled, |
565 | * hence we can't get into perf_event_task_sched_out for this context. |
566 | */ |
567 | void perf_event_disable(struct perf_event *event) |
568 | { |
569 | struct perf_event_context *ctx = event->ctx; |
570 | struct task_struct *task = ctx->task; |
571 | |
572 | if (!task) { |
573 | /* |
574 | * Disable the event on the cpu that it's on |
575 | */ |
576 | smp_call_function_single(event->cpu, __perf_event_disable, |
577 | event, 1); |
578 | return; |
579 | } |
580 | |
581 | retry: |
582 | task_oncpu_function_call(task, __perf_event_disable, event); |
583 | |
584 | raw_spin_lock_irq(&ctx->lock); |
585 | /* |
586 | * If the event is still active, we need to retry the cross-call. |
587 | */ |
588 | if (event->state == PERF_EVENT_STATE_ACTIVE) { |
589 | raw_spin_unlock_irq(&ctx->lock); |
590 | goto retry; |
591 | } |
592 | |
593 | /* |
594 | * Since we have the lock this context can't be scheduled |
595 | * in, so we can change the state safely. |
596 | */ |
597 | if (event->state == PERF_EVENT_STATE_INACTIVE) { |
598 | update_group_times(event); |
599 | event->state = PERF_EVENT_STATE_OFF; |
600 | } |
601 | |
602 | raw_spin_unlock_irq(&ctx->lock); |
603 | } |
604 | |
605 | static int |
606 | event_sched_in(struct perf_event *event, |
607 | struct perf_cpu_context *cpuctx, |
608 | struct perf_event_context *ctx) |
609 | { |
610 | if (event->state <= PERF_EVENT_STATE_OFF) |
611 | return 0; |
612 | |
613 | event->state = PERF_EVENT_STATE_ACTIVE; |
614 | event->oncpu = smp_processor_id(); |
615 | /* |
616 | * The new state must be visible before we turn it on in the hardware: |
617 | */ |
618 | smp_wmb(); |
619 | |
620 | if (event->pmu->enable(event)) { |
621 | event->state = PERF_EVENT_STATE_INACTIVE; |
622 | event->oncpu = -1; |
623 | return -EAGAIN; |
624 | } |
625 | |
626 | event->tstamp_running += ctx->time - event->tstamp_stopped; |
627 | |
628 | if (!is_software_event(event)) |
629 | cpuctx->active_oncpu++; |
630 | ctx->nr_active++; |
631 | |
632 | if (event->attr.exclusive) |
633 | cpuctx->exclusive = 1; |
634 | |
635 | return 0; |
636 | } |
637 | |
638 | static int |
639 | group_sched_in(struct perf_event *group_event, |
640 | struct perf_cpu_context *cpuctx, |
641 | struct perf_event_context *ctx) |
642 | { |
643 | struct perf_event *event, *partial_group; |
644 | int ret; |
645 | |
646 | if (group_event->state == PERF_EVENT_STATE_OFF) |
647 | return 0; |
648 | |
649 | ret = hw_perf_group_sched_in(group_event, cpuctx, ctx); |
650 | if (ret) |
651 | return ret < 0 ? ret : 0; |
652 | |
653 | if (event_sched_in(group_event, cpuctx, ctx)) |
654 | return -EAGAIN; |
655 | |
656 | /* |
657 | * Schedule in siblings as one group (if any): |
658 | */ |
659 | list_for_each_entry(event, &group_event->sibling_list, group_entry) { |
660 | if (event_sched_in(event, cpuctx, ctx)) { |
661 | partial_group = event; |
662 | goto group_error; |
663 | } |
664 | } |
665 | |
666 | return 0; |
667 | |
668 | group_error: |
669 | /* |
670 | * Groups can be scheduled in as one unit only, so undo any |
671 | * partial group before returning: |
672 | */ |
673 | list_for_each_entry(event, &group_event->sibling_list, group_entry) { |
674 | if (event == partial_group) |
675 | break; |
676 | event_sched_out(event, cpuctx, ctx); |
677 | } |
678 | event_sched_out(group_event, cpuctx, ctx); |
679 | |
680 | return -EAGAIN; |
681 | } |
682 | |
683 | /* |
684 | * Work out whether we can put this event group on the CPU now. |
685 | */ |
686 | static int group_can_go_on(struct perf_event *event, |
687 | struct perf_cpu_context *cpuctx, |
688 | int can_add_hw) |
689 | { |
690 | /* |
691 | * Groups consisting entirely of software events can always go on. |
692 | */ |
693 | if (event->group_flags & PERF_GROUP_SOFTWARE) |
694 | return 1; |
695 | /* |
696 | * If an exclusive group is already on, no other hardware |
697 | * events can go on. |
698 | */ |
699 | if (cpuctx->exclusive) |
700 | return 0; |
701 | /* |
702 | * If this group is exclusive and there are already |
703 | * events on the CPU, it can't go on. |
704 | */ |
705 | if (event->attr.exclusive && cpuctx->active_oncpu) |
706 | return 0; |
707 | /* |
708 | * Otherwise, try to add it if all previous groups were able |
709 | * to go on. |
710 | */ |
711 | return can_add_hw; |
712 | } |
713 | |
714 | static void add_event_to_ctx(struct perf_event *event, |
715 | struct perf_event_context *ctx) |
716 | { |
717 | list_add_event(event, ctx); |
718 | event->tstamp_enabled = ctx->time; |
719 | event->tstamp_running = ctx->time; |
720 | event->tstamp_stopped = ctx->time; |
721 | } |
722 | |
723 | /* |
724 | * Cross CPU call to install and enable a performance event |
725 | * |
726 | * Must be called with ctx->mutex held |
727 | */ |
728 | static void __perf_install_in_context(void *info) |
729 | { |
730 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
731 | struct perf_event *event = info; |
732 | struct perf_event_context *ctx = event->ctx; |
733 | struct perf_event *leader = event->group_leader; |
734 | int err; |
735 | |
736 | /* |
737 | * If this is a task context, we need to check whether it is |
738 | * the current task context of this cpu. If not it has been |
739 | * scheduled out before the smp call arrived. |
740 | * Or possibly this is the right context but it isn't |
741 | * on this cpu because it had no events. |
742 | */ |
743 | if (ctx->task && cpuctx->task_ctx != ctx) { |
744 | if (cpuctx->task_ctx || ctx->task != current) |
745 | return; |
746 | cpuctx->task_ctx = ctx; |
747 | } |
748 | |
749 | raw_spin_lock(&ctx->lock); |
750 | ctx->is_active = 1; |
751 | update_context_time(ctx); |
752 | |
753 | /* |
754 | * Protect the list operation against NMI by disabling the |
755 | * events on a global level. NOP for non NMI based events. |
756 | */ |
757 | perf_disable(); |
758 | |
759 | add_event_to_ctx(event, ctx); |
760 | |
761 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
762 | goto unlock; |
763 | |
764 | /* |
765 | * Don't put the event on if it is disabled or if |
766 | * it is in a group and the group isn't on. |
767 | */ |
768 | if (event->state != PERF_EVENT_STATE_INACTIVE || |
769 | (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)) |
770 | goto unlock; |
771 | |
772 | /* |
773 | * An exclusive event can't go on if there are already active |
774 | * hardware events, and no hardware event can go on if there |
775 | * is already an exclusive event on. |
776 | */ |
777 | if (!group_can_go_on(event, cpuctx, 1)) |
778 | err = -EEXIST; |
779 | else |
780 | err = event_sched_in(event, cpuctx, ctx); |
781 | |
782 | if (err) { |
783 | /* |
784 | * This event couldn't go on. If it is in a group |
785 | * then we have to pull the whole group off. |
786 | * If the event group is pinned then put it in error state. |
787 | */ |
788 | if (leader != event) |
789 | group_sched_out(leader, cpuctx, ctx); |
790 | if (leader->attr.pinned) { |
791 | update_group_times(leader); |
792 | leader->state = PERF_EVENT_STATE_ERROR; |
793 | } |
794 | } |
795 | |
796 | if (!err && !ctx->task && cpuctx->max_pertask) |
797 | cpuctx->max_pertask--; |
798 | |
799 | unlock: |
800 | perf_enable(); |
801 | |
802 | raw_spin_unlock(&ctx->lock); |
803 | } |
804 | |
805 | /* |
806 | * Attach a performance event to a context |
807 | * |
808 | * First we add the event to the list with the hardware enable bit |
809 | * in event->hw_config cleared. |
810 | * |
811 | * If the event is attached to a task which is on a CPU we use a smp |
812 | * call to enable it in the task context. The task might have been |
813 | * scheduled away, but we check this in the smp call again. |
814 | * |
815 | * Must be called with ctx->mutex held. |
816 | */ |
817 | static void |
818 | perf_install_in_context(struct perf_event_context *ctx, |
819 | struct perf_event *event, |
820 | int cpu) |
821 | { |
822 | struct task_struct *task = ctx->task; |
823 | |
824 | if (!task) { |
825 | /* |
826 | * Per cpu events are installed via an smp call and |
827 | * the install is always successful. |
828 | */ |
829 | smp_call_function_single(cpu, __perf_install_in_context, |
830 | event, 1); |
831 | return; |
832 | } |
833 | |
834 | retry: |
835 | task_oncpu_function_call(task, __perf_install_in_context, |
836 | event); |
837 | |
838 | raw_spin_lock_irq(&ctx->lock); |
839 | /* |
840 | * we need to retry the smp call. |
841 | */ |
842 | if (ctx->is_active && list_empty(&event->group_entry)) { |
843 | raw_spin_unlock_irq(&ctx->lock); |
844 | goto retry; |
845 | } |
846 | |
847 | /* |
848 | * The lock prevents that this context is scheduled in so we |
849 | * can add the event safely, if it the call above did not |
850 | * succeed. |
851 | */ |
852 | if (list_empty(&event->group_entry)) |
853 | add_event_to_ctx(event, ctx); |
854 | raw_spin_unlock_irq(&ctx->lock); |
855 | } |
856 | |
857 | /* |
858 | * Put a event into inactive state and update time fields. |
859 | * Enabling the leader of a group effectively enables all |
860 | * the group members that aren't explicitly disabled, so we |
861 | * have to update their ->tstamp_enabled also. |
862 | * Note: this works for group members as well as group leaders |
863 | * since the non-leader members' sibling_lists will be empty. |
864 | */ |
865 | static void __perf_event_mark_enabled(struct perf_event *event, |
866 | struct perf_event_context *ctx) |
867 | { |
868 | struct perf_event *sub; |
869 | |
870 | event->state = PERF_EVENT_STATE_INACTIVE; |
871 | event->tstamp_enabled = ctx->time - event->total_time_enabled; |
872 | list_for_each_entry(sub, &event->sibling_list, group_entry) |
873 | if (sub->state >= PERF_EVENT_STATE_INACTIVE) |
874 | sub->tstamp_enabled = |
875 | ctx->time - sub->total_time_enabled; |
876 | } |
877 | |
878 | /* |
879 | * Cross CPU call to enable a performance event |
880 | */ |
881 | static void __perf_event_enable(void *info) |
882 | { |
883 | struct perf_event *event = info; |
884 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
885 | struct perf_event_context *ctx = event->ctx; |
886 | struct perf_event *leader = event->group_leader; |
887 | int err; |
888 | |
889 | /* |
890 | * If this is a per-task event, need to check whether this |
891 | * event's task is the current task on this cpu. |
892 | */ |
893 | if (ctx->task && cpuctx->task_ctx != ctx) { |
894 | if (cpuctx->task_ctx || ctx->task != current) |
895 | return; |
896 | cpuctx->task_ctx = ctx; |
897 | } |
898 | |
899 | raw_spin_lock(&ctx->lock); |
900 | ctx->is_active = 1; |
901 | update_context_time(ctx); |
902 | |
903 | if (event->state >= PERF_EVENT_STATE_INACTIVE) |
904 | goto unlock; |
905 | __perf_event_mark_enabled(event, ctx); |
906 | |
907 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
908 | goto unlock; |
909 | |
910 | /* |
911 | * If the event is in a group and isn't the group leader, |
912 | * then don't put it on unless the group is on. |
913 | */ |
914 | if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) |
915 | goto unlock; |
916 | |
917 | if (!group_can_go_on(event, cpuctx, 1)) { |
918 | err = -EEXIST; |
919 | } else { |
920 | perf_disable(); |
921 | if (event == leader) |
922 | err = group_sched_in(event, cpuctx, ctx); |
923 | else |
924 | err = event_sched_in(event, cpuctx, ctx); |
925 | perf_enable(); |
926 | } |
927 | |
928 | if (err) { |
929 | /* |
930 | * If this event can't go on and it's part of a |
931 | * group, then the whole group has to come off. |
932 | */ |
933 | if (leader != event) |
934 | group_sched_out(leader, cpuctx, ctx); |
935 | if (leader->attr.pinned) { |
936 | update_group_times(leader); |
937 | leader->state = PERF_EVENT_STATE_ERROR; |
938 | } |
939 | } |
940 | |
941 | unlock: |
942 | raw_spin_unlock(&ctx->lock); |
943 | } |
944 | |
945 | /* |
946 | * Enable a event. |
947 | * |
948 | * If event->ctx is a cloned context, callers must make sure that |
949 | * every task struct that event->ctx->task could possibly point to |
950 | * remains valid. This condition is satisfied when called through |
951 | * perf_event_for_each_child or perf_event_for_each as described |
952 | * for perf_event_disable. |
953 | */ |
954 | void perf_event_enable(struct perf_event *event) |
955 | { |
956 | struct perf_event_context *ctx = event->ctx; |
957 | struct task_struct *task = ctx->task; |
958 | |
959 | if (!task) { |
960 | /* |
961 | * Enable the event on the cpu that it's on |
962 | */ |
963 | smp_call_function_single(event->cpu, __perf_event_enable, |
964 | event, 1); |
965 | return; |
966 | } |
967 | |
968 | raw_spin_lock_irq(&ctx->lock); |
969 | if (event->state >= PERF_EVENT_STATE_INACTIVE) |
970 | goto out; |
971 | |
972 | /* |
973 | * If the event is in error state, clear that first. |
974 | * That way, if we see the event in error state below, we |
975 | * know that it has gone back into error state, as distinct |
976 | * from the task having been scheduled away before the |
977 | * cross-call arrived. |
978 | */ |
979 | if (event->state == PERF_EVENT_STATE_ERROR) |
980 | event->state = PERF_EVENT_STATE_OFF; |
981 | |
982 | retry: |
983 | raw_spin_unlock_irq(&ctx->lock); |
984 | task_oncpu_function_call(task, __perf_event_enable, event); |
985 | |
986 | raw_spin_lock_irq(&ctx->lock); |
987 | |
988 | /* |
989 | * If the context is active and the event is still off, |
990 | * we need to retry the cross-call. |
991 | */ |
992 | if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) |
993 | goto retry; |
994 | |
995 | /* |
996 | * Since we have the lock this context can't be scheduled |
997 | * in, so we can change the state safely. |
998 | */ |
999 | if (event->state == PERF_EVENT_STATE_OFF) |
1000 | __perf_event_mark_enabled(event, ctx); |
1001 | |
1002 | out: |
1003 | raw_spin_unlock_irq(&ctx->lock); |
1004 | } |
1005 | |
1006 | static int perf_event_refresh(struct perf_event *event, int refresh) |
1007 | { |
1008 | /* |
1009 | * not supported on inherited events |
1010 | */ |
1011 | if (event->attr.inherit) |
1012 | return -EINVAL; |
1013 | |
1014 | atomic_add(refresh, &event->event_limit); |
1015 | perf_event_enable(event); |
1016 | |
1017 | return 0; |
1018 | } |
1019 | |
1020 | enum event_type_t { |
1021 | EVENT_FLEXIBLE = 0x1, |
1022 | EVENT_PINNED = 0x2, |
1023 | EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, |
1024 | }; |
1025 | |
1026 | static void ctx_sched_out(struct perf_event_context *ctx, |
1027 | struct perf_cpu_context *cpuctx, |
1028 | enum event_type_t event_type) |
1029 | { |
1030 | struct perf_event *event; |
1031 | |
1032 | raw_spin_lock(&ctx->lock); |
1033 | ctx->is_active = 0; |
1034 | if (likely(!ctx->nr_events)) |
1035 | goto out; |
1036 | update_context_time(ctx); |
1037 | |
1038 | perf_disable(); |
1039 | if (!ctx->nr_active) |
1040 | goto out_enable; |
1041 | |
1042 | if (event_type & EVENT_PINNED) |
1043 | list_for_each_entry(event, &ctx->pinned_groups, group_entry) |
1044 | group_sched_out(event, cpuctx, ctx); |
1045 | |
1046 | if (event_type & EVENT_FLEXIBLE) |
1047 | list_for_each_entry(event, &ctx->flexible_groups, group_entry) |
1048 | group_sched_out(event, cpuctx, ctx); |
1049 | |
1050 | out_enable: |
1051 | perf_enable(); |
1052 | out: |
1053 | raw_spin_unlock(&ctx->lock); |
1054 | } |
1055 | |
1056 | /* |
1057 | * Test whether two contexts are equivalent, i.e. whether they |
1058 | * have both been cloned from the same version of the same context |
1059 | * and they both have the same number of enabled events. |
1060 | * If the number of enabled events is the same, then the set |
1061 | * of enabled events should be the same, because these are both |
1062 | * inherited contexts, therefore we can't access individual events |
1063 | * in them directly with an fd; we can only enable/disable all |
1064 | * events via prctl, or enable/disable all events in a family |
1065 | * via ioctl, which will have the same effect on both contexts. |
1066 | */ |
1067 | static int context_equiv(struct perf_event_context *ctx1, |
1068 | struct perf_event_context *ctx2) |
1069 | { |
1070 | return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx |
1071 | && ctx1->parent_gen == ctx2->parent_gen |
1072 | && !ctx1->pin_count && !ctx2->pin_count; |
1073 | } |
1074 | |
1075 | static void __perf_event_sync_stat(struct perf_event *event, |
1076 | struct perf_event *next_event) |
1077 | { |
1078 | u64 value; |
1079 | |
1080 | if (!event->attr.inherit_stat) |
1081 | return; |
1082 | |
1083 | /* |
1084 | * Update the event value, we cannot use perf_event_read() |
1085 | * because we're in the middle of a context switch and have IRQs |
1086 | * disabled, which upsets smp_call_function_single(), however |
1087 | * we know the event must be on the current CPU, therefore we |
1088 | * don't need to use it. |
1089 | */ |
1090 | switch (event->state) { |
1091 | case PERF_EVENT_STATE_ACTIVE: |
1092 | event->pmu->read(event); |
1093 | /* fall-through */ |
1094 | |
1095 | case PERF_EVENT_STATE_INACTIVE: |
1096 | update_event_times(event); |
1097 | break; |
1098 | |
1099 | default: |
1100 | break; |
1101 | } |
1102 | |
1103 | /* |
1104 | * In order to keep per-task stats reliable we need to flip the event |
1105 | * values when we flip the contexts. |
1106 | */ |
1107 | value = atomic64_read(&next_event->count); |
1108 | value = atomic64_xchg(&event->count, value); |
1109 | atomic64_set(&next_event->count, value); |
1110 | |
1111 | swap(event->total_time_enabled, next_event->total_time_enabled); |
1112 | swap(event->total_time_running, next_event->total_time_running); |
1113 | |
1114 | /* |
1115 | * Since we swizzled the values, update the user visible data too. |
1116 | */ |
1117 | perf_event_update_userpage(event); |
1118 | perf_event_update_userpage(next_event); |
1119 | } |
1120 | |
1121 | #define list_next_entry(pos, member) \ |
1122 | list_entry(pos->member.next, typeof(*pos), member) |
1123 | |
1124 | static void perf_event_sync_stat(struct perf_event_context *ctx, |
1125 | struct perf_event_context *next_ctx) |
1126 | { |
1127 | struct perf_event *event, *next_event; |
1128 | |
1129 | if (!ctx->nr_stat) |
1130 | return; |
1131 | |
1132 | update_context_time(ctx); |
1133 | |
1134 | event = list_first_entry(&ctx->event_list, |
1135 | struct perf_event, event_entry); |
1136 | |
1137 | next_event = list_first_entry(&next_ctx->event_list, |
1138 | struct perf_event, event_entry); |
1139 | |
1140 | while (&event->event_entry != &ctx->event_list && |
1141 | &next_event->event_entry != &next_ctx->event_list) { |
1142 | |
1143 | __perf_event_sync_stat(event, next_event); |
1144 | |
1145 | event = list_next_entry(event, event_entry); |
1146 | next_event = list_next_entry(next_event, event_entry); |
1147 | } |
1148 | } |
1149 | |
1150 | /* |
1151 | * Called from scheduler to remove the events of the current task, |
1152 | * with interrupts disabled. |
1153 | * |
1154 | * We stop each event and update the event value in event->count. |
1155 | * |
1156 | * This does not protect us against NMI, but disable() |
1157 | * sets the disabled bit in the control field of event _before_ |
1158 | * accessing the event control register. If a NMI hits, then it will |
1159 | * not restart the event. |
1160 | */ |
1161 | void perf_event_task_sched_out(struct task_struct *task, |
1162 | struct task_struct *next) |
1163 | { |
1164 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
1165 | struct perf_event_context *ctx = task->perf_event_ctxp; |
1166 | struct perf_event_context *next_ctx; |
1167 | struct perf_event_context *parent; |
1168 | int do_switch = 1; |
1169 | |
1170 | perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0); |
1171 | |
1172 | if (likely(!ctx || !cpuctx->task_ctx)) |
1173 | return; |
1174 | |
1175 | rcu_read_lock(); |
1176 | parent = rcu_dereference(ctx->parent_ctx); |
1177 | next_ctx = next->perf_event_ctxp; |
1178 | if (parent && next_ctx && |
1179 | rcu_dereference(next_ctx->parent_ctx) == parent) { |
1180 | /* |
1181 | * Looks like the two contexts are clones, so we might be |
1182 | * able to optimize the context switch. We lock both |
1183 | * contexts and check that they are clones under the |
1184 | * lock (including re-checking that neither has been |
1185 | * uncloned in the meantime). It doesn't matter which |
1186 | * order we take the locks because no other cpu could |
1187 | * be trying to lock both of these tasks. |
1188 | */ |
1189 | raw_spin_lock(&ctx->lock); |
1190 | raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); |
1191 | if (context_equiv(ctx, next_ctx)) { |
1192 | /* |
1193 | * XXX do we need a memory barrier of sorts |
1194 | * wrt to rcu_dereference() of perf_event_ctxp |
1195 | */ |
1196 | task->perf_event_ctxp = next_ctx; |
1197 | next->perf_event_ctxp = ctx; |
1198 | ctx->task = next; |
1199 | next_ctx->task = task; |
1200 | do_switch = 0; |
1201 | |
1202 | perf_event_sync_stat(ctx, next_ctx); |
1203 | } |
1204 | raw_spin_unlock(&next_ctx->lock); |
1205 | raw_spin_unlock(&ctx->lock); |
1206 | } |
1207 | rcu_read_unlock(); |
1208 | |
1209 | if (do_switch) { |
1210 | ctx_sched_out(ctx, cpuctx, EVENT_ALL); |
1211 | cpuctx->task_ctx = NULL; |
1212 | } |
1213 | } |
1214 | |
1215 | static void task_ctx_sched_out(struct perf_event_context *ctx, |
1216 | enum event_type_t event_type) |
1217 | { |
1218 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
1219 | |
1220 | if (!cpuctx->task_ctx) |
1221 | return; |
1222 | |
1223 | if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) |
1224 | return; |
1225 | |
1226 | ctx_sched_out(ctx, cpuctx, event_type); |
1227 | cpuctx->task_ctx = NULL; |
1228 | } |
1229 | |
1230 | /* |
1231 | * Called with IRQs disabled |
1232 | */ |
1233 | static void __perf_event_task_sched_out(struct perf_event_context *ctx) |
1234 | { |
1235 | task_ctx_sched_out(ctx, EVENT_ALL); |
1236 | } |
1237 | |
1238 | /* |
1239 | * Called with IRQs disabled |
1240 | */ |
1241 | static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, |
1242 | enum event_type_t event_type) |
1243 | { |
1244 | ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); |
1245 | } |
1246 | |
1247 | static void |
1248 | ctx_pinned_sched_in(struct perf_event_context *ctx, |
1249 | struct perf_cpu_context *cpuctx) |
1250 | { |
1251 | struct perf_event *event; |
1252 | |
1253 | list_for_each_entry(event, &ctx->pinned_groups, group_entry) { |
1254 | if (event->state <= PERF_EVENT_STATE_OFF) |
1255 | continue; |
1256 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
1257 | continue; |
1258 | |
1259 | if (group_can_go_on(event, cpuctx, 1)) |
1260 | group_sched_in(event, cpuctx, ctx); |
1261 | |
1262 | /* |
1263 | * If this pinned group hasn't been scheduled, |
1264 | * put it in error state. |
1265 | */ |
1266 | if (event->state == PERF_EVENT_STATE_INACTIVE) { |
1267 | update_group_times(event); |
1268 | event->state = PERF_EVENT_STATE_ERROR; |
1269 | } |
1270 | } |
1271 | } |
1272 | |
1273 | static void |
1274 | ctx_flexible_sched_in(struct perf_event_context *ctx, |
1275 | struct perf_cpu_context *cpuctx) |
1276 | { |
1277 | struct perf_event *event; |
1278 | int can_add_hw = 1; |
1279 | |
1280 | list_for_each_entry(event, &ctx->flexible_groups, group_entry) { |
1281 | /* Ignore events in OFF or ERROR state */ |
1282 | if (event->state <= PERF_EVENT_STATE_OFF) |
1283 | continue; |
1284 | /* |
1285 | * Listen to the 'cpu' scheduling filter constraint |
1286 | * of events: |
1287 | */ |
1288 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
1289 | continue; |
1290 | |
1291 | if (group_can_go_on(event, cpuctx, can_add_hw)) |
1292 | if (group_sched_in(event, cpuctx, ctx)) |
1293 | can_add_hw = 0; |
1294 | } |
1295 | } |
1296 | |
1297 | static void |
1298 | ctx_sched_in(struct perf_event_context *ctx, |
1299 | struct perf_cpu_context *cpuctx, |
1300 | enum event_type_t event_type) |
1301 | { |
1302 | raw_spin_lock(&ctx->lock); |
1303 | ctx->is_active = 1; |
1304 | if (likely(!ctx->nr_events)) |
1305 | goto out; |
1306 | |
1307 | ctx->timestamp = perf_clock(); |
1308 | |
1309 | perf_disable(); |
1310 | |
1311 | /* |
1312 | * First go through the list and put on any pinned groups |
1313 | * in order to give them the best chance of going on. |
1314 | */ |
1315 | if (event_type & EVENT_PINNED) |
1316 | ctx_pinned_sched_in(ctx, cpuctx); |
1317 | |
1318 | /* Then walk through the lower prio flexible groups */ |
1319 | if (event_type & EVENT_FLEXIBLE) |
1320 | ctx_flexible_sched_in(ctx, cpuctx); |
1321 | |
1322 | perf_enable(); |
1323 | out: |
1324 | raw_spin_unlock(&ctx->lock); |
1325 | } |
1326 | |
1327 | static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, |
1328 | enum event_type_t event_type) |
1329 | { |
1330 | struct perf_event_context *ctx = &cpuctx->ctx; |
1331 | |
1332 | ctx_sched_in(ctx, cpuctx, event_type); |
1333 | } |
1334 | |
1335 | static void task_ctx_sched_in(struct task_struct *task, |
1336 | enum event_type_t event_type) |
1337 | { |
1338 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
1339 | struct perf_event_context *ctx = task->perf_event_ctxp; |
1340 | |
1341 | if (likely(!ctx)) |
1342 | return; |
1343 | if (cpuctx->task_ctx == ctx) |
1344 | return; |
1345 | ctx_sched_in(ctx, cpuctx, event_type); |
1346 | cpuctx->task_ctx = ctx; |
1347 | } |
1348 | /* |
1349 | * Called from scheduler to add the events of the current task |
1350 | * with interrupts disabled. |
1351 | * |
1352 | * We restore the event value and then enable it. |
1353 | * |
1354 | * This does not protect us against NMI, but enable() |
1355 | * sets the enabled bit in the control field of event _before_ |
1356 | * accessing the event control register. If a NMI hits, then it will |
1357 | * keep the event running. |
1358 | */ |
1359 | void perf_event_task_sched_in(struct task_struct *task) |
1360 | { |
1361 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
1362 | struct perf_event_context *ctx = task->perf_event_ctxp; |
1363 | |
1364 | if (likely(!ctx)) |
1365 | return; |
1366 | |
1367 | if (cpuctx->task_ctx == ctx) |
1368 | return; |
1369 | |
1370 | /* |
1371 | * We want to keep the following priority order: |
1372 | * cpu pinned (that don't need to move), task pinned, |
1373 | * cpu flexible, task flexible. |
1374 | */ |
1375 | cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
1376 | |
1377 | ctx_sched_in(ctx, cpuctx, EVENT_PINNED); |
1378 | cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); |
1379 | ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE); |
1380 | |
1381 | cpuctx->task_ctx = ctx; |
1382 | } |
1383 | |
1384 | #define MAX_INTERRUPTS (~0ULL) |
1385 | |
1386 | static void perf_log_throttle(struct perf_event *event, int enable); |
1387 | |
1388 | static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) |
1389 | { |
1390 | u64 frequency = event->attr.sample_freq; |
1391 | u64 sec = NSEC_PER_SEC; |
1392 | u64 divisor, dividend; |
1393 | |
1394 | int count_fls, nsec_fls, frequency_fls, sec_fls; |
1395 | |
1396 | count_fls = fls64(count); |
1397 | nsec_fls = fls64(nsec); |
1398 | frequency_fls = fls64(frequency); |
1399 | sec_fls = 30; |
1400 | |
1401 | /* |
1402 | * We got @count in @nsec, with a target of sample_freq HZ |
1403 | * the target period becomes: |
1404 | * |
1405 | * @count * 10^9 |
1406 | * period = ------------------- |
1407 | * @nsec * sample_freq |
1408 | * |
1409 | */ |
1410 | |
1411 | /* |
1412 | * Reduce accuracy by one bit such that @a and @b converge |
1413 | * to a similar magnitude. |
1414 | */ |
1415 | #define REDUCE_FLS(a, b) \ |
1416 | do { \ |
1417 | if (a##_fls > b##_fls) { \ |
1418 | a >>= 1; \ |
1419 | a##_fls--; \ |
1420 | } else { \ |
1421 | b >>= 1; \ |
1422 | b##_fls--; \ |
1423 | } \ |
1424 | } while (0) |
1425 | |
1426 | /* |
1427 | * Reduce accuracy until either term fits in a u64, then proceed with |
1428 | * the other, so that finally we can do a u64/u64 division. |
1429 | */ |
1430 | while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { |
1431 | REDUCE_FLS(nsec, frequency); |
1432 | REDUCE_FLS(sec, count); |
1433 | } |
1434 | |
1435 | if (count_fls + sec_fls > 64) { |
1436 | divisor = nsec * frequency; |
1437 | |
1438 | while (count_fls + sec_fls > 64) { |
1439 | REDUCE_FLS(count, sec); |
1440 | divisor >>= 1; |
1441 | } |
1442 | |
1443 | dividend = count * sec; |
1444 | } else { |
1445 | dividend = count * sec; |
1446 | |
1447 | while (nsec_fls + frequency_fls > 64) { |
1448 | REDUCE_FLS(nsec, frequency); |
1449 | dividend >>= 1; |
1450 | } |
1451 | |
1452 | divisor = nsec * frequency; |
1453 | } |
1454 | |
1455 | return div64_u64(dividend, divisor); |
1456 | } |
1457 | |
1458 | static void perf_event_stop(struct perf_event *event) |
1459 | { |
1460 | if (!event->pmu->stop) |
1461 | return event->pmu->disable(event); |
1462 | |
1463 | return event->pmu->stop(event); |
1464 | } |
1465 | |
1466 | static int perf_event_start(struct perf_event *event) |
1467 | { |
1468 | if (!event->pmu->start) |
1469 | return event->pmu->enable(event); |
1470 | |
1471 | return event->pmu->start(event); |
1472 | } |
1473 | |
1474 | static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) |
1475 | { |
1476 | struct hw_perf_event *hwc = &event->hw; |
1477 | u64 period, sample_period; |
1478 | s64 delta; |
1479 | |
1480 | period = perf_calculate_period(event, nsec, count); |
1481 | |
1482 | delta = (s64)(period - hwc->sample_period); |
1483 | delta = (delta + 7) / 8; /* low pass filter */ |
1484 | |
1485 | sample_period = hwc->sample_period + delta; |
1486 | |
1487 | if (!sample_period) |
1488 | sample_period = 1; |
1489 | |
1490 | hwc->sample_period = sample_period; |
1491 | |
1492 | if (atomic64_read(&hwc->period_left) > 8*sample_period) { |
1493 | perf_disable(); |
1494 | perf_event_stop(event); |
1495 | atomic64_set(&hwc->period_left, 0); |
1496 | perf_event_start(event); |
1497 | perf_enable(); |
1498 | } |
1499 | } |
1500 | |
1501 | static void perf_ctx_adjust_freq(struct perf_event_context *ctx) |
1502 | { |
1503 | struct perf_event *event; |
1504 | struct hw_perf_event *hwc; |
1505 | u64 interrupts, now; |
1506 | s64 delta; |
1507 | |
1508 | raw_spin_lock(&ctx->lock); |
1509 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
1510 | if (event->state != PERF_EVENT_STATE_ACTIVE) |
1511 | continue; |
1512 | |
1513 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
1514 | continue; |
1515 | |
1516 | hwc = &event->hw; |
1517 | |
1518 | interrupts = hwc->interrupts; |
1519 | hwc->interrupts = 0; |
1520 | |
1521 | /* |
1522 | * unthrottle events on the tick |
1523 | */ |
1524 | if (interrupts == MAX_INTERRUPTS) { |
1525 | perf_log_throttle(event, 1); |
1526 | perf_disable(); |
1527 | event->pmu->unthrottle(event); |
1528 | perf_enable(); |
1529 | } |
1530 | |
1531 | if (!event->attr.freq || !event->attr.sample_freq) |
1532 | continue; |
1533 | |
1534 | perf_disable(); |
1535 | event->pmu->read(event); |
1536 | now = atomic64_read(&event->count); |
1537 | delta = now - hwc->freq_count_stamp; |
1538 | hwc->freq_count_stamp = now; |
1539 | |
1540 | if (delta > 0) |
1541 | perf_adjust_period(event, TICK_NSEC, delta); |
1542 | perf_enable(); |
1543 | } |
1544 | raw_spin_unlock(&ctx->lock); |
1545 | } |
1546 | |
1547 | /* |
1548 | * Round-robin a context's events: |
1549 | */ |
1550 | static void rotate_ctx(struct perf_event_context *ctx) |
1551 | { |
1552 | raw_spin_lock(&ctx->lock); |
1553 | |
1554 | /* Rotate the first entry last of non-pinned groups */ |
1555 | list_rotate_left(&ctx->flexible_groups); |
1556 | |
1557 | raw_spin_unlock(&ctx->lock); |
1558 | } |
1559 | |
1560 | void perf_event_task_tick(struct task_struct *curr) |
1561 | { |
1562 | struct perf_cpu_context *cpuctx; |
1563 | struct perf_event_context *ctx; |
1564 | int rotate = 0; |
1565 | |
1566 | if (!atomic_read(&nr_events)) |
1567 | return; |
1568 | |
1569 | cpuctx = &__get_cpu_var(perf_cpu_context); |
1570 | if (cpuctx->ctx.nr_events && |
1571 | cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) |
1572 | rotate = 1; |
1573 | |
1574 | ctx = curr->perf_event_ctxp; |
1575 | if (ctx && ctx->nr_events && ctx->nr_events != ctx->nr_active) |
1576 | rotate = 1; |
1577 | |
1578 | perf_ctx_adjust_freq(&cpuctx->ctx); |
1579 | if (ctx) |
1580 | perf_ctx_adjust_freq(ctx); |
1581 | |
1582 | if (!rotate) |
1583 | return; |
1584 | |
1585 | perf_disable(); |
1586 | cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); |
1587 | if (ctx) |
1588 | task_ctx_sched_out(ctx, EVENT_FLEXIBLE); |
1589 | |
1590 | rotate_ctx(&cpuctx->ctx); |
1591 | if (ctx) |
1592 | rotate_ctx(ctx); |
1593 | |
1594 | cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); |
1595 | if (ctx) |
1596 | task_ctx_sched_in(curr, EVENT_FLEXIBLE); |
1597 | perf_enable(); |
1598 | } |
1599 | |
1600 | static int event_enable_on_exec(struct perf_event *event, |
1601 | struct perf_event_context *ctx) |
1602 | { |
1603 | if (!event->attr.enable_on_exec) |
1604 | return 0; |
1605 | |
1606 | event->attr.enable_on_exec = 0; |
1607 | if (event->state >= PERF_EVENT_STATE_INACTIVE) |
1608 | return 0; |
1609 | |
1610 | __perf_event_mark_enabled(event, ctx); |
1611 | |
1612 | return 1; |
1613 | } |
1614 | |
1615 | /* |
1616 | * Enable all of a task's events that have been marked enable-on-exec. |
1617 | * This expects task == current. |
1618 | */ |
1619 | static void perf_event_enable_on_exec(struct task_struct *task) |
1620 | { |
1621 | struct perf_event_context *ctx; |
1622 | struct perf_event *event; |
1623 | unsigned long flags; |
1624 | int enabled = 0; |
1625 | int ret; |
1626 | |
1627 | local_irq_save(flags); |
1628 | ctx = task->perf_event_ctxp; |
1629 | if (!ctx || !ctx->nr_events) |
1630 | goto out; |
1631 | |
1632 | __perf_event_task_sched_out(ctx); |
1633 | |
1634 | raw_spin_lock(&ctx->lock); |
1635 | |
1636 | list_for_each_entry(event, &ctx->pinned_groups, group_entry) { |
1637 | ret = event_enable_on_exec(event, ctx); |
1638 | if (ret) |
1639 | enabled = 1; |
1640 | } |
1641 | |
1642 | list_for_each_entry(event, &ctx->flexible_groups, group_entry) { |
1643 | ret = event_enable_on_exec(event, ctx); |
1644 | if (ret) |
1645 | enabled = 1; |
1646 | } |
1647 | |
1648 | /* |
1649 | * Unclone this context if we enabled any event. |
1650 | */ |
1651 | if (enabled) |
1652 | unclone_ctx(ctx); |
1653 | |
1654 | raw_spin_unlock(&ctx->lock); |
1655 | |
1656 | perf_event_task_sched_in(task); |
1657 | out: |
1658 | local_irq_restore(flags); |
1659 | } |
1660 | |
1661 | /* |
1662 | * Cross CPU call to read the hardware event |
1663 | */ |
1664 | static void __perf_event_read(void *info) |
1665 | { |
1666 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
1667 | struct perf_event *event = info; |
1668 | struct perf_event_context *ctx = event->ctx; |
1669 | |
1670 | /* |
1671 | * If this is a task context, we need to check whether it is |
1672 | * the current task context of this cpu. If not it has been |
1673 | * scheduled out before the smp call arrived. In that case |
1674 | * event->count would have been updated to a recent sample |
1675 | * when the event was scheduled out. |
1676 | */ |
1677 | if (ctx->task && cpuctx->task_ctx != ctx) |
1678 | return; |
1679 | |
1680 | raw_spin_lock(&ctx->lock); |
1681 | update_context_time(ctx); |
1682 | update_event_times(event); |
1683 | raw_spin_unlock(&ctx->lock); |
1684 | |
1685 | event->pmu->read(event); |
1686 | } |
1687 | |
1688 | static u64 perf_event_read(struct perf_event *event) |
1689 | { |
1690 | /* |
1691 | * If event is enabled and currently active on a CPU, update the |
1692 | * value in the event structure: |
1693 | */ |
1694 | if (event->state == PERF_EVENT_STATE_ACTIVE) { |
1695 | smp_call_function_single(event->oncpu, |
1696 | __perf_event_read, event, 1); |
1697 | } else if (event->state == PERF_EVENT_STATE_INACTIVE) { |
1698 | struct perf_event_context *ctx = event->ctx; |
1699 | unsigned long flags; |
1700 | |
1701 | raw_spin_lock_irqsave(&ctx->lock, flags); |
1702 | update_context_time(ctx); |
1703 | update_event_times(event); |
1704 | raw_spin_unlock_irqrestore(&ctx->lock, flags); |
1705 | } |
1706 | |
1707 | return atomic64_read(&event->count); |
1708 | } |
1709 | |
1710 | /* |
1711 | * Initialize the perf_event context in a task_struct: |
1712 | */ |
1713 | static void |
1714 | __perf_event_init_context(struct perf_event_context *ctx, |
1715 | struct task_struct *task) |
1716 | { |
1717 | raw_spin_lock_init(&ctx->lock); |
1718 | mutex_init(&ctx->mutex); |
1719 | INIT_LIST_HEAD(&ctx->pinned_groups); |
1720 | INIT_LIST_HEAD(&ctx->flexible_groups); |
1721 | INIT_LIST_HEAD(&ctx->event_list); |
1722 | atomic_set(&ctx->refcount, 1); |
1723 | ctx->task = task; |
1724 | } |
1725 | |
1726 | static struct perf_event_context *find_get_context(pid_t pid, int cpu) |
1727 | { |
1728 | struct perf_event_context *ctx; |
1729 | struct perf_cpu_context *cpuctx; |
1730 | struct task_struct *task; |
1731 | unsigned long flags; |
1732 | int err; |
1733 | |
1734 | if (pid == -1 && cpu != -1) { |
1735 | /* Must be root to operate on a CPU event: */ |
1736 | if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) |
1737 | return ERR_PTR(-EACCES); |
1738 | |
1739 | if (cpu < 0 || cpu >= nr_cpumask_bits) |
1740 | return ERR_PTR(-EINVAL); |
1741 | |
1742 | /* |
1743 | * We could be clever and allow to attach a event to an |
1744 | * offline CPU and activate it when the CPU comes up, but |
1745 | * that's for later. |
1746 | */ |
1747 | if (!cpu_online(cpu)) |
1748 | return ERR_PTR(-ENODEV); |
1749 | |
1750 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
1751 | ctx = &cpuctx->ctx; |
1752 | get_ctx(ctx); |
1753 | |
1754 | return ctx; |
1755 | } |
1756 | |
1757 | rcu_read_lock(); |
1758 | if (!pid) |
1759 | task = current; |
1760 | else |
1761 | task = find_task_by_vpid(pid); |
1762 | if (task) |
1763 | get_task_struct(task); |
1764 | rcu_read_unlock(); |
1765 | |
1766 | if (!task) |
1767 | return ERR_PTR(-ESRCH); |
1768 | |
1769 | /* |
1770 | * Can't attach events to a dying task. |
1771 | */ |
1772 | err = -ESRCH; |
1773 | if (task->flags & PF_EXITING) |
1774 | goto errout; |
1775 | |
1776 | /* Reuse ptrace permission checks for now. */ |
1777 | err = -EACCES; |
1778 | if (!ptrace_may_access(task, PTRACE_MODE_READ)) |
1779 | goto errout; |
1780 | |
1781 | retry: |
1782 | ctx = perf_lock_task_context(task, &flags); |
1783 | if (ctx) { |
1784 | unclone_ctx(ctx); |
1785 | raw_spin_unlock_irqrestore(&ctx->lock, flags); |
1786 | } |
1787 | |
1788 | if (!ctx) { |
1789 | ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); |
1790 | err = -ENOMEM; |
1791 | if (!ctx) |
1792 | goto errout; |
1793 | __perf_event_init_context(ctx, task); |
1794 | get_ctx(ctx); |
1795 | if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) { |
1796 | /* |
1797 | * We raced with some other task; use |
1798 | * the context they set. |
1799 | */ |
1800 | kfree(ctx); |
1801 | goto retry; |
1802 | } |
1803 | get_task_struct(task); |
1804 | } |
1805 | |
1806 | put_task_struct(task); |
1807 | return ctx; |
1808 | |
1809 | errout: |
1810 | put_task_struct(task); |
1811 | return ERR_PTR(err); |
1812 | } |
1813 | |
1814 | static void perf_event_free_filter(struct perf_event *event); |
1815 | |
1816 | static void free_event_rcu(struct rcu_head *head) |
1817 | { |
1818 | struct perf_event *event; |
1819 | |
1820 | event = container_of(head, struct perf_event, rcu_head); |
1821 | if (event->ns) |
1822 | put_pid_ns(event->ns); |
1823 | perf_event_free_filter(event); |
1824 | kfree(event); |
1825 | } |
1826 | |
1827 | static void perf_pending_sync(struct perf_event *event); |
1828 | |
1829 | static void free_event(struct perf_event *event) |
1830 | { |
1831 | perf_pending_sync(event); |
1832 | |
1833 | if (!event->parent) { |
1834 | atomic_dec(&nr_events); |
1835 | if (event->attr.mmap) |
1836 | atomic_dec(&nr_mmap_events); |
1837 | if (event->attr.comm) |
1838 | atomic_dec(&nr_comm_events); |
1839 | if (event->attr.task) |
1840 | atomic_dec(&nr_task_events); |
1841 | } |
1842 | |
1843 | if (event->output) { |
1844 | fput(event->output->filp); |
1845 | event->output = NULL; |
1846 | } |
1847 | |
1848 | if (event->destroy) |
1849 | event->destroy(event); |
1850 | |
1851 | put_ctx(event->ctx); |
1852 | call_rcu(&event->rcu_head, free_event_rcu); |
1853 | } |
1854 | |
1855 | int perf_event_release_kernel(struct perf_event *event) |
1856 | { |
1857 | struct perf_event_context *ctx = event->ctx; |
1858 | |
1859 | WARN_ON_ONCE(ctx->parent_ctx); |
1860 | mutex_lock(&ctx->mutex); |
1861 | perf_event_remove_from_context(event); |
1862 | mutex_unlock(&ctx->mutex); |
1863 | |
1864 | mutex_lock(&event->owner->perf_event_mutex); |
1865 | list_del_init(&event->owner_entry); |
1866 | mutex_unlock(&event->owner->perf_event_mutex); |
1867 | put_task_struct(event->owner); |
1868 | |
1869 | free_event(event); |
1870 | |
1871 | return 0; |
1872 | } |
1873 | EXPORT_SYMBOL_GPL(perf_event_release_kernel); |
1874 | |
1875 | /* |
1876 | * Called when the last reference to the file is gone. |
1877 | */ |
1878 | static int perf_release(struct inode *inode, struct file *file) |
1879 | { |
1880 | struct perf_event *event = file->private_data; |
1881 | |
1882 | file->private_data = NULL; |
1883 | |
1884 | return perf_event_release_kernel(event); |
1885 | } |
1886 | |
1887 | static int perf_event_read_size(struct perf_event *event) |
1888 | { |
1889 | int entry = sizeof(u64); /* value */ |
1890 | int size = 0; |
1891 | int nr = 1; |
1892 | |
1893 | if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
1894 | size += sizeof(u64); |
1895 | |
1896 | if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
1897 | size += sizeof(u64); |
1898 | |
1899 | if (event->attr.read_format & PERF_FORMAT_ID) |
1900 | entry += sizeof(u64); |
1901 | |
1902 | if (event->attr.read_format & PERF_FORMAT_GROUP) { |
1903 | nr += event->group_leader->nr_siblings; |
1904 | size += sizeof(u64); |
1905 | } |
1906 | |
1907 | size += entry * nr; |
1908 | |
1909 | return size; |
1910 | } |
1911 | |
1912 | u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) |
1913 | { |
1914 | struct perf_event *child; |
1915 | u64 total = 0; |
1916 | |
1917 | *enabled = 0; |
1918 | *running = 0; |
1919 | |
1920 | mutex_lock(&event->child_mutex); |
1921 | total += perf_event_read(event); |
1922 | *enabled += event->total_time_enabled + |
1923 | atomic64_read(&event->child_total_time_enabled); |
1924 | *running += event->total_time_running + |
1925 | atomic64_read(&event->child_total_time_running); |
1926 | |
1927 | list_for_each_entry(child, &event->child_list, child_list) { |
1928 | total += perf_event_read(child); |
1929 | *enabled += child->total_time_enabled; |
1930 | *running += child->total_time_running; |
1931 | } |
1932 | mutex_unlock(&event->child_mutex); |
1933 | |
1934 | return total; |
1935 | } |
1936 | EXPORT_SYMBOL_GPL(perf_event_read_value); |
1937 | |
1938 | static int perf_event_read_group(struct perf_event *event, |
1939 | u64 read_format, char __user *buf) |
1940 | { |
1941 | struct perf_event *leader = event->group_leader, *sub; |
1942 | int n = 0, size = 0, ret = -EFAULT; |
1943 | struct perf_event_context *ctx = leader->ctx; |
1944 | u64 values[5]; |
1945 | u64 count, enabled, running; |
1946 | |
1947 | mutex_lock(&ctx->mutex); |
1948 | count = perf_event_read_value(leader, &enabled, &running); |
1949 | |
1950 | values[n++] = 1 + leader->nr_siblings; |
1951 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
1952 | values[n++] = enabled; |
1953 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
1954 | values[n++] = running; |
1955 | values[n++] = count; |
1956 | if (read_format & PERF_FORMAT_ID) |
1957 | values[n++] = primary_event_id(leader); |
1958 | |
1959 | size = n * sizeof(u64); |
1960 | |
1961 | if (copy_to_user(buf, values, size)) |
1962 | goto unlock; |
1963 | |
1964 | ret = size; |
1965 | |
1966 | list_for_each_entry(sub, &leader->sibling_list, group_entry) { |
1967 | n = 0; |
1968 | |
1969 | values[n++] = perf_event_read_value(sub, &enabled, &running); |
1970 | if (read_format & PERF_FORMAT_ID) |
1971 | values[n++] = primary_event_id(sub); |
1972 | |
1973 | size = n * sizeof(u64); |
1974 | |
1975 | if (copy_to_user(buf + ret, values, size)) { |
1976 | ret = -EFAULT; |
1977 | goto unlock; |
1978 | } |
1979 | |
1980 | ret += size; |
1981 | } |
1982 | unlock: |
1983 | mutex_unlock(&ctx->mutex); |
1984 | |
1985 | return ret; |
1986 | } |
1987 | |
1988 | static int perf_event_read_one(struct perf_event *event, |
1989 | u64 read_format, char __user *buf) |
1990 | { |
1991 | u64 enabled, running; |
1992 | u64 values[4]; |
1993 | int n = 0; |
1994 | |
1995 | values[n++] = perf_event_read_value(event, &enabled, &running); |
1996 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
1997 | values[n++] = enabled; |
1998 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
1999 | values[n++] = running; |
2000 | if (read_format & PERF_FORMAT_ID) |
2001 | values[n++] = primary_event_id(event); |
2002 | |
2003 | if (copy_to_user(buf, values, n * sizeof(u64))) |
2004 | return -EFAULT; |
2005 | |
2006 | return n * sizeof(u64); |
2007 | } |
2008 | |
2009 | /* |
2010 | * Read the performance event - simple non blocking version for now |
2011 | */ |
2012 | static ssize_t |
2013 | perf_read_hw(struct perf_event *event, char __user *buf, size_t count) |
2014 | { |
2015 | u64 read_format = event->attr.read_format; |
2016 | int ret; |
2017 | |
2018 | /* |
2019 | * Return end-of-file for a read on a event that is in |
2020 | * error state (i.e. because it was pinned but it couldn't be |
2021 | * scheduled on to the CPU at some point). |
2022 | */ |
2023 | if (event->state == PERF_EVENT_STATE_ERROR) |
2024 | return 0; |
2025 | |
2026 | if (count < perf_event_read_size(event)) |
2027 | return -ENOSPC; |
2028 | |
2029 | WARN_ON_ONCE(event->ctx->parent_ctx); |
2030 | if (read_format & PERF_FORMAT_GROUP) |
2031 | ret = perf_event_read_group(event, read_format, buf); |
2032 | else |
2033 | ret = perf_event_read_one(event, read_format, buf); |
2034 | |
2035 | return ret; |
2036 | } |
2037 | |
2038 | static ssize_t |
2039 | perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) |
2040 | { |
2041 | struct perf_event *event = file->private_data; |
2042 | |
2043 | return perf_read_hw(event, buf, count); |
2044 | } |
2045 | |
2046 | static unsigned int perf_poll(struct file *file, poll_table *wait) |
2047 | { |
2048 | struct perf_event *event = file->private_data; |
2049 | struct perf_mmap_data *data; |
2050 | unsigned int events = POLL_HUP; |
2051 | |
2052 | rcu_read_lock(); |
2053 | data = rcu_dereference(event->data); |
2054 | if (data) |
2055 | events = atomic_xchg(&data->poll, 0); |
2056 | rcu_read_unlock(); |
2057 | |
2058 | poll_wait(file, &event->waitq, wait); |
2059 | |
2060 | return events; |
2061 | } |
2062 | |
2063 | static void perf_event_reset(struct perf_event *event) |
2064 | { |
2065 | (void)perf_event_read(event); |
2066 | atomic64_set(&event->count, 0); |
2067 | perf_event_update_userpage(event); |
2068 | } |
2069 | |
2070 | /* |
2071 | * Holding the top-level event's child_mutex means that any |
2072 | * descendant process that has inherited this event will block |
2073 | * in sync_child_event if it goes to exit, thus satisfying the |
2074 | * task existence requirements of perf_event_enable/disable. |
2075 | */ |
2076 | static void perf_event_for_each_child(struct perf_event *event, |
2077 | void (*func)(struct perf_event *)) |
2078 | { |
2079 | struct perf_event *child; |
2080 | |
2081 | WARN_ON_ONCE(event->ctx->parent_ctx); |
2082 | mutex_lock(&event->child_mutex); |
2083 | func(event); |
2084 | list_for_each_entry(child, &event->child_list, child_list) |
2085 | func(child); |
2086 | mutex_unlock(&event->child_mutex); |
2087 | } |
2088 | |
2089 | static void perf_event_for_each(struct perf_event *event, |
2090 | void (*func)(struct perf_event *)) |
2091 | { |
2092 | struct perf_event_context *ctx = event->ctx; |
2093 | struct perf_event *sibling; |
2094 | |
2095 | WARN_ON_ONCE(ctx->parent_ctx); |
2096 | mutex_lock(&ctx->mutex); |
2097 | event = event->group_leader; |
2098 | |
2099 | perf_event_for_each_child(event, func); |
2100 | func(event); |
2101 | list_for_each_entry(sibling, &event->sibling_list, group_entry) |
2102 | perf_event_for_each_child(event, func); |
2103 | mutex_unlock(&ctx->mutex); |
2104 | } |
2105 | |
2106 | static int perf_event_period(struct perf_event *event, u64 __user *arg) |
2107 | { |
2108 | struct perf_event_context *ctx = event->ctx; |
2109 | unsigned long size; |
2110 | int ret = 0; |
2111 | u64 value; |
2112 | |
2113 | if (!event->attr.sample_period) |
2114 | return -EINVAL; |
2115 | |
2116 | size = copy_from_user(&value, arg, sizeof(value)); |
2117 | if (size != sizeof(value)) |
2118 | return -EFAULT; |
2119 | |
2120 | if (!value) |
2121 | return -EINVAL; |
2122 | |
2123 | raw_spin_lock_irq(&ctx->lock); |
2124 | if (event->attr.freq) { |
2125 | if (value > sysctl_perf_event_sample_rate) { |
2126 | ret = -EINVAL; |
2127 | goto unlock; |
2128 | } |
2129 | |
2130 | event->attr.sample_freq = value; |
2131 | } else { |
2132 | event->attr.sample_period = value; |
2133 | event->hw.sample_period = value; |
2134 | } |
2135 | unlock: |
2136 | raw_spin_unlock_irq(&ctx->lock); |
2137 | |
2138 | return ret; |
2139 | } |
2140 | |
2141 | static int perf_event_set_output(struct perf_event *event, int output_fd); |
2142 | static int perf_event_set_filter(struct perf_event *event, void __user *arg); |
2143 | |
2144 | static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
2145 | { |
2146 | struct perf_event *event = file->private_data; |
2147 | void (*func)(struct perf_event *); |
2148 | u32 flags = arg; |
2149 | |
2150 | switch (cmd) { |
2151 | case PERF_EVENT_IOC_ENABLE: |
2152 | func = perf_event_enable; |
2153 | break; |
2154 | case PERF_EVENT_IOC_DISABLE: |
2155 | func = perf_event_disable; |
2156 | break; |
2157 | case PERF_EVENT_IOC_RESET: |
2158 | func = perf_event_reset; |
2159 | break; |
2160 | |
2161 | case PERF_EVENT_IOC_REFRESH: |
2162 | return perf_event_refresh(event, arg); |
2163 | |
2164 | case PERF_EVENT_IOC_PERIOD: |
2165 | return perf_event_period(event, (u64 __user *)arg); |
2166 | |
2167 | case PERF_EVENT_IOC_SET_OUTPUT: |
2168 | return perf_event_set_output(event, arg); |
2169 | |
2170 | case PERF_EVENT_IOC_SET_FILTER: |
2171 | return perf_event_set_filter(event, (void __user *)arg); |
2172 | |
2173 | default: |
2174 | return -ENOTTY; |
2175 | } |
2176 | |
2177 | if (flags & PERF_IOC_FLAG_GROUP) |
2178 | perf_event_for_each(event, func); |
2179 | else |
2180 | perf_event_for_each_child(event, func); |
2181 | |
2182 | return 0; |
2183 | } |
2184 | |
2185 | int perf_event_task_enable(void) |
2186 | { |
2187 | struct perf_event *event; |
2188 | |
2189 | mutex_lock(¤t->perf_event_mutex); |
2190 | list_for_each_entry(event, ¤t->perf_event_list, owner_entry) |
2191 | perf_event_for_each_child(event, perf_event_enable); |
2192 | mutex_unlock(¤t->perf_event_mutex); |
2193 | |
2194 | return 0; |
2195 | } |
2196 | |
2197 | int perf_event_task_disable(void) |
2198 | { |
2199 | struct perf_event *event; |
2200 | |
2201 | mutex_lock(¤t->perf_event_mutex); |
2202 | list_for_each_entry(event, ¤t->perf_event_list, owner_entry) |
2203 | perf_event_for_each_child(event, perf_event_disable); |
2204 | mutex_unlock(¤t->perf_event_mutex); |
2205 | |
2206 | return 0; |
2207 | } |
2208 | |
2209 | #ifndef PERF_EVENT_INDEX_OFFSET |
2210 | # define PERF_EVENT_INDEX_OFFSET 0 |
2211 | #endif |
2212 | |
2213 | static int perf_event_index(struct perf_event *event) |
2214 | { |
2215 | if (event->state != PERF_EVENT_STATE_ACTIVE) |
2216 | return 0; |
2217 | |
2218 | return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET; |
2219 | } |
2220 | |
2221 | /* |
2222 | * Callers need to ensure there can be no nesting of this function, otherwise |
2223 | * the seqlock logic goes bad. We can not serialize this because the arch |
2224 | * code calls this from NMI context. |
2225 | */ |
2226 | void perf_event_update_userpage(struct perf_event *event) |
2227 | { |
2228 | struct perf_event_mmap_page *userpg; |
2229 | struct perf_mmap_data *data; |
2230 | |
2231 | rcu_read_lock(); |
2232 | data = rcu_dereference(event->data); |
2233 | if (!data) |
2234 | goto unlock; |
2235 | |
2236 | userpg = data->user_page; |
2237 | |
2238 | /* |
2239 | * Disable preemption so as to not let the corresponding user-space |
2240 | * spin too long if we get preempted. |
2241 | */ |
2242 | preempt_disable(); |
2243 | ++userpg->lock; |
2244 | barrier(); |
2245 | userpg->index = perf_event_index(event); |
2246 | userpg->offset = atomic64_read(&event->count); |
2247 | if (event->state == PERF_EVENT_STATE_ACTIVE) |
2248 | userpg->offset -= atomic64_read(&event->hw.prev_count); |
2249 | |
2250 | userpg->time_enabled = event->total_time_enabled + |
2251 | atomic64_read(&event->child_total_time_enabled); |
2252 | |
2253 | userpg->time_running = event->total_time_running + |
2254 | atomic64_read(&event->child_total_time_running); |
2255 | |
2256 | barrier(); |
2257 | ++userpg->lock; |
2258 | preempt_enable(); |
2259 | unlock: |
2260 | rcu_read_unlock(); |
2261 | } |
2262 | |
2263 | static unsigned long perf_data_size(struct perf_mmap_data *data) |
2264 | { |
2265 | return data->nr_pages << (PAGE_SHIFT + data->data_order); |
2266 | } |
2267 | |
2268 | #ifndef CONFIG_PERF_USE_VMALLOC |
2269 | |
2270 | /* |
2271 | * Back perf_mmap() with regular GFP_KERNEL-0 pages. |
2272 | */ |
2273 | |
2274 | static struct page * |
2275 | perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff) |
2276 | { |
2277 | if (pgoff > data->nr_pages) |
2278 | return NULL; |
2279 | |
2280 | if (pgoff == 0) |
2281 | return virt_to_page(data->user_page); |
2282 | |
2283 | return virt_to_page(data->data_pages[pgoff - 1]); |
2284 | } |
2285 | |
2286 | static struct perf_mmap_data * |
2287 | perf_mmap_data_alloc(struct perf_event *event, int nr_pages) |
2288 | { |
2289 | struct perf_mmap_data *data; |
2290 | unsigned long size; |
2291 | int i; |
2292 | |
2293 | WARN_ON(atomic_read(&event->mmap_count)); |
2294 | |
2295 | size = sizeof(struct perf_mmap_data); |
2296 | size += nr_pages * sizeof(void *); |
2297 | |
2298 | data = kzalloc(size, GFP_KERNEL); |
2299 | if (!data) |
2300 | goto fail; |
2301 | |
2302 | data->user_page = (void *)get_zeroed_page(GFP_KERNEL); |
2303 | if (!data->user_page) |
2304 | goto fail_user_page; |
2305 | |
2306 | for (i = 0; i < nr_pages; i++) { |
2307 | data->data_pages[i] = (void *)get_zeroed_page(GFP_KERNEL); |
2308 | if (!data->data_pages[i]) |
2309 | goto fail_data_pages; |
2310 | } |
2311 | |
2312 | data->data_order = 0; |
2313 | data->nr_pages = nr_pages; |
2314 | |
2315 | return data; |
2316 | |
2317 | fail_data_pages: |
2318 | for (i--; i >= 0; i--) |
2319 | free_page((unsigned long)data->data_pages[i]); |
2320 | |
2321 | free_page((unsigned long)data->user_page); |
2322 | |
2323 | fail_user_page: |
2324 | kfree(data); |
2325 | |
2326 | fail: |
2327 | return NULL; |
2328 | } |
2329 | |
2330 | static void perf_mmap_free_page(unsigned long addr) |
2331 | { |
2332 | struct page *page = virt_to_page((void *)addr); |
2333 | |
2334 | page->mapping = NULL; |
2335 | __free_page(page); |
2336 | } |
2337 | |
2338 | static void perf_mmap_data_free(struct perf_mmap_data *data) |
2339 | { |
2340 | int i; |
2341 | |
2342 | perf_mmap_free_page((unsigned long)data->user_page); |
2343 | for (i = 0; i < data->nr_pages; i++) |
2344 | perf_mmap_free_page((unsigned long)data->data_pages[i]); |
2345 | kfree(data); |
2346 | } |
2347 | |
2348 | #else |
2349 | |
2350 | /* |
2351 | * Back perf_mmap() with vmalloc memory. |
2352 | * |
2353 | * Required for architectures that have d-cache aliasing issues. |
2354 | */ |
2355 | |
2356 | static struct page * |
2357 | perf_mmap_to_page(struct perf_mmap_data *data, unsigned long pgoff) |
2358 | { |
2359 | if (pgoff > (1UL << data->data_order)) |
2360 | return NULL; |
2361 | |
2362 | return vmalloc_to_page((void *)data->user_page + pgoff * PAGE_SIZE); |
2363 | } |
2364 | |
2365 | static void perf_mmap_unmark_page(void *addr) |
2366 | { |
2367 | struct page *page = vmalloc_to_page(addr); |
2368 | |
2369 | page->mapping = NULL; |
2370 | } |
2371 | |
2372 | static void perf_mmap_data_free_work(struct work_struct *work) |
2373 | { |
2374 | struct perf_mmap_data *data; |
2375 | void *base; |
2376 | int i, nr; |
2377 | |
2378 | data = container_of(work, struct perf_mmap_data, work); |
2379 | nr = 1 << data->data_order; |
2380 | |
2381 | base = data->user_page; |
2382 | for (i = 0; i < nr + 1; i++) |
2383 | perf_mmap_unmark_page(base + (i * PAGE_SIZE)); |
2384 | |
2385 | vfree(base); |
2386 | kfree(data); |
2387 | } |
2388 | |
2389 | static void perf_mmap_data_free(struct perf_mmap_data *data) |
2390 | { |
2391 | schedule_work(&data->work); |
2392 | } |
2393 | |
2394 | static struct perf_mmap_data * |
2395 | perf_mmap_data_alloc(struct perf_event *event, int nr_pages) |
2396 | { |
2397 | struct perf_mmap_data *data; |
2398 | unsigned long size; |
2399 | void *all_buf; |
2400 | |
2401 | WARN_ON(atomic_read(&event->mmap_count)); |
2402 | |
2403 | size = sizeof(struct perf_mmap_data); |
2404 | size += sizeof(void *); |
2405 | |
2406 | data = kzalloc(size, GFP_KERNEL); |
2407 | if (!data) |
2408 | goto fail; |
2409 | |
2410 | INIT_WORK(&data->work, perf_mmap_data_free_work); |
2411 | |
2412 | all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE); |
2413 | if (!all_buf) |
2414 | goto fail_all_buf; |
2415 | |
2416 | data->user_page = all_buf; |
2417 | data->data_pages[0] = all_buf + PAGE_SIZE; |
2418 | data->data_order = ilog2(nr_pages); |
2419 | data->nr_pages = 1; |
2420 | |
2421 | return data; |
2422 | |
2423 | fail_all_buf: |
2424 | kfree(data); |
2425 | |
2426 | fail: |
2427 | return NULL; |
2428 | } |
2429 | |
2430 | #endif |
2431 | |
2432 | static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
2433 | { |
2434 | struct perf_event *event = vma->vm_file->private_data; |
2435 | struct perf_mmap_data *data; |
2436 | int ret = VM_FAULT_SIGBUS; |
2437 | |
2438 | if (vmf->flags & FAULT_FLAG_MKWRITE) { |
2439 | if (vmf->pgoff == 0) |
2440 | ret = 0; |
2441 | return ret; |
2442 | } |
2443 | |
2444 | rcu_read_lock(); |
2445 | data = rcu_dereference(event->data); |
2446 | if (!data) |
2447 | goto unlock; |
2448 | |
2449 | if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) |
2450 | goto unlock; |
2451 | |
2452 | vmf->page = perf_mmap_to_page(data, vmf->pgoff); |
2453 | if (!vmf->page) |
2454 | goto unlock; |
2455 | |
2456 | get_page(vmf->page); |
2457 | vmf->page->mapping = vma->vm_file->f_mapping; |
2458 | vmf->page->index = vmf->pgoff; |
2459 | |
2460 | ret = 0; |
2461 | unlock: |
2462 | rcu_read_unlock(); |
2463 | |
2464 | return ret; |
2465 | } |
2466 | |
2467 | static void |
2468 | perf_mmap_data_init(struct perf_event *event, struct perf_mmap_data *data) |
2469 | { |
2470 | long max_size = perf_data_size(data); |
2471 | |
2472 | atomic_set(&data->lock, -1); |
2473 | |
2474 | if (event->attr.watermark) { |
2475 | data->watermark = min_t(long, max_size, |
2476 | event->attr.wakeup_watermark); |
2477 | } |
2478 | |
2479 | if (!data->watermark) |
2480 | data->watermark = max_size / 2; |
2481 | |
2482 | |
2483 | rcu_assign_pointer(event->data, data); |
2484 | } |
2485 | |
2486 | static void perf_mmap_data_free_rcu(struct rcu_head *rcu_head) |
2487 | { |
2488 | struct perf_mmap_data *data; |
2489 | |
2490 | data = container_of(rcu_head, struct perf_mmap_data, rcu_head); |
2491 | perf_mmap_data_free(data); |
2492 | } |
2493 | |
2494 | static void perf_mmap_data_release(struct perf_event *event) |
2495 | { |
2496 | struct perf_mmap_data *data = event->data; |
2497 | |
2498 | WARN_ON(atomic_read(&event->mmap_count)); |
2499 | |
2500 | rcu_assign_pointer(event->data, NULL); |
2501 | call_rcu(&data->rcu_head, perf_mmap_data_free_rcu); |
2502 | } |
2503 | |
2504 | static void perf_mmap_open(struct vm_area_struct *vma) |
2505 | { |
2506 | struct perf_event *event = vma->vm_file->private_data; |
2507 | |
2508 | atomic_inc(&event->mmap_count); |
2509 | } |
2510 | |
2511 | static void perf_mmap_close(struct vm_area_struct *vma) |
2512 | { |
2513 | struct perf_event *event = vma->vm_file->private_data; |
2514 | |
2515 | WARN_ON_ONCE(event->ctx->parent_ctx); |
2516 | if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { |
2517 | unsigned long size = perf_data_size(event->data); |
2518 | struct user_struct *user = current_user(); |
2519 | |
2520 | atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm); |
2521 | vma->vm_mm->locked_vm -= event->data->nr_locked; |
2522 | perf_mmap_data_release(event); |
2523 | mutex_unlock(&event->mmap_mutex); |
2524 | } |
2525 | } |
2526 | |
2527 | static const struct vm_operations_struct perf_mmap_vmops = { |
2528 | .open = perf_mmap_open, |
2529 | .close = perf_mmap_close, |
2530 | .fault = perf_mmap_fault, |
2531 | .page_mkwrite = perf_mmap_fault, |
2532 | }; |
2533 | |
2534 | static int perf_mmap(struct file *file, struct vm_area_struct *vma) |
2535 | { |
2536 | struct perf_event *event = file->private_data; |
2537 | unsigned long user_locked, user_lock_limit; |
2538 | struct user_struct *user = current_user(); |
2539 | unsigned long locked, lock_limit; |
2540 | struct perf_mmap_data *data; |
2541 | unsigned long vma_size; |
2542 | unsigned long nr_pages; |
2543 | long user_extra, extra; |
2544 | int ret = 0; |
2545 | |
2546 | if (!(vma->vm_flags & VM_SHARED)) |
2547 | return -EINVAL; |
2548 | |
2549 | vma_size = vma->vm_end - vma->vm_start; |
2550 | nr_pages = (vma_size / PAGE_SIZE) - 1; |
2551 | |
2552 | /* |
2553 | * If we have data pages ensure they're a power-of-two number, so we |
2554 | * can do bitmasks instead of modulo. |
2555 | */ |
2556 | if (nr_pages != 0 && !is_power_of_2(nr_pages)) |
2557 | return -EINVAL; |
2558 | |
2559 | if (vma_size != PAGE_SIZE * (1 + nr_pages)) |
2560 | return -EINVAL; |
2561 | |
2562 | if (vma->vm_pgoff != 0) |
2563 | return -EINVAL; |
2564 | |
2565 | WARN_ON_ONCE(event->ctx->parent_ctx); |
2566 | mutex_lock(&event->mmap_mutex); |
2567 | if (event->output) { |
2568 | ret = -EINVAL; |
2569 | goto unlock; |
2570 | } |
2571 | |
2572 | if (atomic_inc_not_zero(&event->mmap_count)) { |
2573 | if (nr_pages != event->data->nr_pages) |
2574 | ret = -EINVAL; |
2575 | goto unlock; |
2576 | } |
2577 | |
2578 | user_extra = nr_pages + 1; |
2579 | user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); |
2580 | |
2581 | /* |
2582 | * Increase the limit linearly with more CPUs: |
2583 | */ |
2584 | user_lock_limit *= num_online_cpus(); |
2585 | |
2586 | user_locked = atomic_long_read(&user->locked_vm) + user_extra; |
2587 | |
2588 | extra = 0; |
2589 | if (user_locked > user_lock_limit) |
2590 | extra = user_locked - user_lock_limit; |
2591 | |
2592 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
2593 | lock_limit >>= PAGE_SHIFT; |
2594 | locked = vma->vm_mm->locked_vm + extra; |
2595 | |
2596 | if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && |
2597 | !capable(CAP_IPC_LOCK)) { |
2598 | ret = -EPERM; |
2599 | goto unlock; |
2600 | } |
2601 | |
2602 | WARN_ON(event->data); |
2603 | |
2604 | data = perf_mmap_data_alloc(event, nr_pages); |
2605 | ret = -ENOMEM; |
2606 | if (!data) |
2607 | goto unlock; |
2608 | |
2609 | ret = 0; |
2610 | perf_mmap_data_init(event, data); |
2611 | |
2612 | atomic_set(&event->mmap_count, 1); |
2613 | atomic_long_add(user_extra, &user->locked_vm); |
2614 | vma->vm_mm->locked_vm += extra; |
2615 | event->data->nr_locked = extra; |
2616 | if (vma->vm_flags & VM_WRITE) |
2617 | event->data->writable = 1; |
2618 | |
2619 | unlock: |
2620 | mutex_unlock(&event->mmap_mutex); |
2621 | |
2622 | vma->vm_flags |= VM_RESERVED; |
2623 | vma->vm_ops = &perf_mmap_vmops; |
2624 | |
2625 | return ret; |
2626 | } |
2627 | |
2628 | static int perf_fasync(int fd, struct file *filp, int on) |
2629 | { |
2630 | struct inode *inode = filp->f_path.dentry->d_inode; |
2631 | struct perf_event *event = filp->private_data; |
2632 | int retval; |
2633 | |
2634 | mutex_lock(&inode->i_mutex); |
2635 | retval = fasync_helper(fd, filp, on, &event->fasync); |
2636 | mutex_unlock(&inode->i_mutex); |
2637 | |
2638 | if (retval < 0) |
2639 | return retval; |
2640 | |
2641 | return 0; |
2642 | } |
2643 | |
2644 | static const struct file_operations perf_fops = { |
2645 | .release = perf_release, |
2646 | .read = perf_read, |
2647 | .poll = perf_poll, |
2648 | .unlocked_ioctl = perf_ioctl, |
2649 | .compat_ioctl = perf_ioctl, |
2650 | .mmap = perf_mmap, |
2651 | .fasync = perf_fasync, |
2652 | }; |
2653 | |
2654 | /* |
2655 | * Perf event wakeup |
2656 | * |
2657 | * If there's data, ensure we set the poll() state and publish everything |
2658 | * to user-space before waking everybody up. |
2659 | */ |
2660 | |
2661 | void perf_event_wakeup(struct perf_event *event) |
2662 | { |
2663 | wake_up_all(&event->waitq); |
2664 | |
2665 | if (event->pending_kill) { |
2666 | kill_fasync(&event->fasync, SIGIO, event->pending_kill); |
2667 | event->pending_kill = 0; |
2668 | } |
2669 | } |
2670 | |
2671 | /* |
2672 | * Pending wakeups |
2673 | * |
2674 | * Handle the case where we need to wakeup up from NMI (or rq->lock) context. |
2675 | * |
2676 | * The NMI bit means we cannot possibly take locks. Therefore, maintain a |
2677 | * single linked list and use cmpxchg() to add entries lockless. |
2678 | */ |
2679 | |
2680 | static void perf_pending_event(struct perf_pending_entry *entry) |
2681 | { |
2682 | struct perf_event *event = container_of(entry, |
2683 | struct perf_event, pending); |
2684 | |
2685 | if (event->pending_disable) { |
2686 | event->pending_disable = 0; |
2687 | __perf_event_disable(event); |
2688 | } |
2689 | |
2690 | if (event->pending_wakeup) { |
2691 | event->pending_wakeup = 0; |
2692 | perf_event_wakeup(event); |
2693 | } |
2694 | } |
2695 | |
2696 | #define PENDING_TAIL ((struct perf_pending_entry *)-1UL) |
2697 | |
2698 | static DEFINE_PER_CPU(struct perf_pending_entry *, perf_pending_head) = { |
2699 | PENDING_TAIL, |
2700 | }; |
2701 | |
2702 | static void perf_pending_queue(struct perf_pending_entry *entry, |
2703 | void (*func)(struct perf_pending_entry *)) |
2704 | { |
2705 | struct perf_pending_entry **head; |
2706 | |
2707 | if (cmpxchg(&entry->next, NULL, PENDING_TAIL) != NULL) |
2708 | return; |
2709 | |
2710 | entry->func = func; |
2711 | |
2712 | head = &get_cpu_var(perf_pending_head); |
2713 | |
2714 | do { |
2715 | entry->next = *head; |
2716 | } while (cmpxchg(head, entry->next, entry) != entry->next); |
2717 | |
2718 | set_perf_event_pending(); |
2719 | |
2720 | put_cpu_var(perf_pending_head); |
2721 | } |
2722 | |
2723 | static int __perf_pending_run(void) |
2724 | { |
2725 | struct perf_pending_entry *list; |
2726 | int nr = 0; |
2727 | |
2728 | list = xchg(&__get_cpu_var(perf_pending_head), PENDING_TAIL); |
2729 | while (list != PENDING_TAIL) { |
2730 | void (*func)(struct perf_pending_entry *); |
2731 | struct perf_pending_entry *entry = list; |
2732 | |
2733 | list = list->next; |
2734 | |
2735 | func = entry->func; |
2736 | entry->next = NULL; |
2737 | /* |
2738 | * Ensure we observe the unqueue before we issue the wakeup, |
2739 | * so that we won't be waiting forever. |
2740 | * -- see perf_not_pending(). |
2741 | */ |
2742 | smp_wmb(); |
2743 | |
2744 | func(entry); |
2745 | nr++; |
2746 | } |
2747 | |
2748 | return nr; |
2749 | } |
2750 | |
2751 | static inline int perf_not_pending(struct perf_event *event) |
2752 | { |
2753 | /* |
2754 | * If we flush on whatever cpu we run, there is a chance we don't |
2755 | * need to wait. |
2756 | */ |
2757 | get_cpu(); |
2758 | __perf_pending_run(); |
2759 | put_cpu(); |
2760 | |
2761 | /* |
2762 | * Ensure we see the proper queue state before going to sleep |
2763 | * so that we do not miss the wakeup. -- see perf_pending_handle() |
2764 | */ |
2765 | smp_rmb(); |
2766 | return event->pending.next == NULL; |
2767 | } |
2768 | |
2769 | static void perf_pending_sync(struct perf_event *event) |
2770 | { |
2771 | wait_event(event->waitq, perf_not_pending(event)); |
2772 | } |
2773 | |
2774 | void perf_event_do_pending(void) |
2775 | { |
2776 | __perf_pending_run(); |
2777 | } |
2778 | |
2779 | /* |
2780 | * Callchain support -- arch specific |
2781 | */ |
2782 | |
2783 | __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) |
2784 | { |
2785 | return NULL; |
2786 | } |
2787 | |
2788 | __weak |
2789 | void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip) |
2790 | { |
2791 | } |
2792 | |
2793 | |
2794 | /* |
2795 | * Output |
2796 | */ |
2797 | static bool perf_output_space(struct perf_mmap_data *data, unsigned long tail, |
2798 | unsigned long offset, unsigned long head) |
2799 | { |
2800 | unsigned long mask; |
2801 | |
2802 | if (!data->writable) |
2803 | return true; |
2804 | |
2805 | mask = perf_data_size(data) - 1; |
2806 | |
2807 | offset = (offset - tail) & mask; |
2808 | head = (head - tail) & mask; |
2809 | |
2810 | if ((int)(head - offset) < 0) |
2811 | return false; |
2812 | |
2813 | return true; |
2814 | } |
2815 | |
2816 | static void perf_output_wakeup(struct perf_output_handle *handle) |
2817 | { |
2818 | atomic_set(&handle->data->poll, POLL_IN); |
2819 | |
2820 | if (handle->nmi) { |
2821 | handle->event->pending_wakeup = 1; |
2822 | perf_pending_queue(&handle->event->pending, |
2823 | perf_pending_event); |
2824 | } else |
2825 | perf_event_wakeup(handle->event); |
2826 | } |
2827 | |
2828 | /* |
2829 | * Curious locking construct. |
2830 | * |
2831 | * We need to ensure a later event_id doesn't publish a head when a former |
2832 | * event_id isn't done writing. However since we need to deal with NMIs we |
2833 | * cannot fully serialize things. |
2834 | * |
2835 | * What we do is serialize between CPUs so we only have to deal with NMI |
2836 | * nesting on a single CPU. |
2837 | * |
2838 | * We only publish the head (and generate a wakeup) when the outer-most |
2839 | * event_id completes. |
2840 | */ |
2841 | static void perf_output_lock(struct perf_output_handle *handle) |
2842 | { |
2843 | struct perf_mmap_data *data = handle->data; |
2844 | int cur, cpu = get_cpu(); |
2845 | |
2846 | handle->locked = 0; |
2847 | |
2848 | for (;;) { |
2849 | cur = atomic_cmpxchg(&data->lock, -1, cpu); |
2850 | if (cur == -1) { |
2851 | handle->locked = 1; |
2852 | break; |
2853 | } |
2854 | if (cur == cpu) |
2855 | break; |
2856 | |
2857 | cpu_relax(); |
2858 | } |
2859 | } |
2860 | |
2861 | static void perf_output_unlock(struct perf_output_handle *handle) |
2862 | { |
2863 | struct perf_mmap_data *data = handle->data; |
2864 | unsigned long head; |
2865 | int cpu; |
2866 | |
2867 | data->done_head = data->head; |
2868 | |
2869 | if (!handle->locked) |
2870 | goto out; |
2871 | |
2872 | again: |
2873 | /* |
2874 | * The xchg implies a full barrier that ensures all writes are done |
2875 | * before we publish the new head, matched by a rmb() in userspace when |
2876 | * reading this position. |
2877 | */ |
2878 | while ((head = atomic_long_xchg(&data->done_head, 0))) |
2879 | data->user_page->data_head = head; |
2880 | |
2881 | /* |
2882 | * NMI can happen here, which means we can miss a done_head update. |
2883 | */ |
2884 | |
2885 | cpu = atomic_xchg(&data->lock, -1); |
2886 | WARN_ON_ONCE(cpu != smp_processor_id()); |
2887 | |
2888 | /* |
2889 | * Therefore we have to validate we did not indeed do so. |
2890 | */ |
2891 | if (unlikely(atomic_long_read(&data->done_head))) { |
2892 | /* |
2893 | * Since we had it locked, we can lock it again. |
2894 | */ |
2895 | while (atomic_cmpxchg(&data->lock, -1, cpu) != -1) |
2896 | cpu_relax(); |
2897 | |
2898 | goto again; |
2899 | } |
2900 | |
2901 | if (atomic_xchg(&data->wakeup, 0)) |
2902 | perf_output_wakeup(handle); |
2903 | out: |
2904 | put_cpu(); |
2905 | } |
2906 | |
2907 | void perf_output_copy(struct perf_output_handle *handle, |
2908 | const void *buf, unsigned int len) |
2909 | { |
2910 | unsigned int pages_mask; |
2911 | unsigned long offset; |
2912 | unsigned int size; |
2913 | void **pages; |
2914 | |
2915 | offset = handle->offset; |
2916 | pages_mask = handle->data->nr_pages - 1; |
2917 | pages = handle->data->data_pages; |
2918 | |
2919 | do { |
2920 | unsigned long page_offset; |
2921 | unsigned long page_size; |
2922 | int nr; |
2923 | |
2924 | nr = (offset >> PAGE_SHIFT) & pages_mask; |
2925 | page_size = 1UL << (handle->data->data_order + PAGE_SHIFT); |
2926 | page_offset = offset & (page_size - 1); |
2927 | size = min_t(unsigned int, page_size - page_offset, len); |
2928 | |
2929 | memcpy(pages[nr] + page_offset, buf, size); |
2930 | |
2931 | len -= size; |
2932 | buf += size; |
2933 | offset += size; |
2934 | } while (len); |
2935 | |
2936 | handle->offset = offset; |
2937 | |
2938 | /* |
2939 | * Check we didn't copy past our reservation window, taking the |
2940 | * possible unsigned int wrap into account. |
2941 | */ |
2942 | WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0); |
2943 | } |
2944 | |
2945 | int perf_output_begin(struct perf_output_handle *handle, |
2946 | struct perf_event *event, unsigned int size, |
2947 | int nmi, int sample) |
2948 | { |
2949 | struct perf_event *output_event; |
2950 | struct perf_mmap_data *data; |
2951 | unsigned long tail, offset, head; |
2952 | int have_lost; |
2953 | struct { |
2954 | struct perf_event_header header; |
2955 | u64 id; |
2956 | u64 lost; |
2957 | } lost_event; |
2958 | |
2959 | rcu_read_lock(); |
2960 | /* |
2961 | * For inherited events we send all the output towards the parent. |
2962 | */ |
2963 | if (event->parent) |
2964 | event = event->parent; |
2965 | |
2966 | output_event = rcu_dereference(event->output); |
2967 | if (output_event) |
2968 | event = output_event; |
2969 | |
2970 | data = rcu_dereference(event->data); |
2971 | if (!data) |
2972 | goto out; |
2973 | |
2974 | handle->data = data; |
2975 | handle->event = event; |
2976 | handle->nmi = nmi; |
2977 | handle->sample = sample; |
2978 | |
2979 | if (!data->nr_pages) |
2980 | goto fail; |
2981 | |
2982 | have_lost = atomic_read(&data->lost); |
2983 | if (have_lost) |
2984 | size += sizeof(lost_event); |
2985 | |
2986 | perf_output_lock(handle); |
2987 | |
2988 | do { |
2989 | /* |
2990 | * Userspace could choose to issue a mb() before updating the |
2991 | * tail pointer. So that all reads will be completed before the |
2992 | * write is issued. |
2993 | */ |
2994 | tail = ACCESS_ONCE(data->user_page->data_tail); |
2995 | smp_rmb(); |
2996 | offset = head = atomic_long_read(&data->head); |
2997 | head += size; |
2998 | if (unlikely(!perf_output_space(data, tail, offset, head))) |
2999 | goto fail; |
3000 | } while (atomic_long_cmpxchg(&data->head, offset, head) != offset); |
3001 | |
3002 | handle->offset = offset; |
3003 | handle->head = head; |
3004 | |
3005 | if (head - tail > data->watermark) |
3006 | atomic_set(&data->wakeup, 1); |
3007 | |
3008 | if (have_lost) { |
3009 | lost_event.header.type = PERF_RECORD_LOST; |
3010 | lost_event.header.misc = 0; |
3011 | lost_event.header.size = sizeof(lost_event); |
3012 | lost_event.id = event->id; |
3013 | lost_event.lost = atomic_xchg(&data->lost, 0); |
3014 | |
3015 | perf_output_put(handle, lost_event); |
3016 | } |
3017 | |
3018 | return 0; |
3019 | |
3020 | fail: |
3021 | atomic_inc(&data->lost); |
3022 | perf_output_unlock(handle); |
3023 | out: |
3024 | rcu_read_unlock(); |
3025 | |
3026 | return -ENOSPC; |
3027 | } |
3028 | |
3029 | void perf_output_end(struct perf_output_handle *handle) |
3030 | { |
3031 | struct perf_event *event = handle->event; |
3032 | struct perf_mmap_data *data = handle->data; |
3033 | |
3034 | int wakeup_events = event->attr.wakeup_events; |
3035 | |
3036 | if (handle->sample && wakeup_events) { |
3037 | int events = atomic_inc_return(&data->events); |
3038 | if (events >= wakeup_events) { |
3039 | atomic_sub(wakeup_events, &data->events); |
3040 | atomic_set(&data->wakeup, 1); |
3041 | } |
3042 | } |
3043 | |
3044 | perf_output_unlock(handle); |
3045 | rcu_read_unlock(); |
3046 | } |
3047 | |
3048 | static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) |
3049 | { |
3050 | /* |
3051 | * only top level events have the pid namespace they were created in |
3052 | */ |
3053 | if (event->parent) |
3054 | event = event->parent; |
3055 | |
3056 | return task_tgid_nr_ns(p, event->ns); |
3057 | } |
3058 | |
3059 | static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) |
3060 | { |
3061 | /* |
3062 | * only top level events have the pid namespace they were created in |
3063 | */ |
3064 | if (event->parent) |
3065 | event = event->parent; |
3066 | |
3067 | return task_pid_nr_ns(p, event->ns); |
3068 | } |
3069 | |
3070 | static void perf_output_read_one(struct perf_output_handle *handle, |
3071 | struct perf_event *event) |
3072 | { |
3073 | u64 read_format = event->attr.read_format; |
3074 | u64 values[4]; |
3075 | int n = 0; |
3076 | |
3077 | values[n++] = atomic64_read(&event->count); |
3078 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { |
3079 | values[n++] = event->total_time_enabled + |
3080 | atomic64_read(&event->child_total_time_enabled); |
3081 | } |
3082 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { |
3083 | values[n++] = event->total_time_running + |
3084 | atomic64_read(&event->child_total_time_running); |
3085 | } |
3086 | if (read_format & PERF_FORMAT_ID) |
3087 | values[n++] = primary_event_id(event); |
3088 | |
3089 | perf_output_copy(handle, values, n * sizeof(u64)); |
3090 | } |
3091 | |
3092 | /* |
3093 | * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. |
3094 | */ |
3095 | static void perf_output_read_group(struct perf_output_handle *handle, |
3096 | struct perf_event *event) |
3097 | { |
3098 | struct perf_event *leader = event->group_leader, *sub; |
3099 | u64 read_format = event->attr.read_format; |
3100 | u64 values[5]; |
3101 | int n = 0; |
3102 | |
3103 | values[n++] = 1 + leader->nr_siblings; |
3104 | |
3105 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) |
3106 | values[n++] = leader->total_time_enabled; |
3107 | |
3108 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) |
3109 | values[n++] = leader->total_time_running; |
3110 | |
3111 | if (leader != event) |
3112 | leader->pmu->read(leader); |
3113 | |
3114 | values[n++] = atomic64_read(&leader->count); |
3115 | if (read_format & PERF_FORMAT_ID) |
3116 | values[n++] = primary_event_id(leader); |
3117 | |
3118 | perf_output_copy(handle, values, n * sizeof(u64)); |
3119 | |
3120 | list_for_each_entry(sub, &leader->sibling_list, group_entry) { |
3121 | n = 0; |
3122 | |
3123 | if (sub != event) |
3124 | sub->pmu->read(sub); |
3125 | |
3126 | values[n++] = atomic64_read(&sub->count); |
3127 | if (read_format & PERF_FORMAT_ID) |
3128 | values[n++] = primary_event_id(sub); |
3129 | |
3130 | perf_output_copy(handle, values, n * sizeof(u64)); |
3131 | } |
3132 | } |
3133 | |
3134 | static void perf_output_read(struct perf_output_handle *handle, |
3135 | struct perf_event *event) |
3136 | { |
3137 | if (event->attr.read_format & PERF_FORMAT_GROUP) |
3138 | perf_output_read_group(handle, event); |
3139 | else |
3140 | perf_output_read_one(handle, event); |
3141 | } |
3142 | |
3143 | void perf_output_sample(struct perf_output_handle *handle, |
3144 | struct perf_event_header *header, |
3145 | struct perf_sample_data *data, |
3146 | struct perf_event *event) |
3147 | { |
3148 | u64 sample_type = data->type; |
3149 | |
3150 | perf_output_put(handle, *header); |
3151 | |
3152 | if (sample_type & PERF_SAMPLE_IP) |
3153 | perf_output_put(handle, data->ip); |
3154 | |
3155 | if (sample_type & PERF_SAMPLE_TID) |
3156 | perf_output_put(handle, data->tid_entry); |
3157 | |
3158 | if (sample_type & PERF_SAMPLE_TIME) |
3159 | perf_output_put(handle, data->time); |
3160 | |
3161 | if (sample_type & PERF_SAMPLE_ADDR) |
3162 | perf_output_put(handle, data->addr); |
3163 | |
3164 | if (sample_type & PERF_SAMPLE_ID) |
3165 | perf_output_put(handle, data->id); |
3166 | |
3167 | if (sample_type & PERF_SAMPLE_STREAM_ID) |
3168 | perf_output_put(handle, data->stream_id); |
3169 | |
3170 | if (sample_type & PERF_SAMPLE_CPU) |
3171 | perf_output_put(handle, data->cpu_entry); |
3172 | |
3173 | if (sample_type & PERF_SAMPLE_PERIOD) |
3174 | perf_output_put(handle, data->period); |
3175 | |
3176 | if (sample_type & PERF_SAMPLE_READ) |
3177 | perf_output_read(handle, event); |
3178 | |
3179 | if (sample_type & PERF_SAMPLE_CALLCHAIN) { |
3180 | if (data->callchain) { |
3181 | int size = 1; |
3182 | |
3183 | if (data->callchain) |
3184 | size += data->callchain->nr; |
3185 | |
3186 | size *= sizeof(u64); |
3187 | |
3188 | perf_output_copy(handle, data->callchain, size); |
3189 | } else { |
3190 | u64 nr = 0; |
3191 | perf_output_put(handle, nr); |
3192 | } |
3193 | } |
3194 | |
3195 | if (sample_type & PERF_SAMPLE_RAW) { |
3196 | if (data->raw) { |
3197 | perf_output_put(handle, data->raw->size); |
3198 | perf_output_copy(handle, data->raw->data, |
3199 | data->raw->size); |
3200 | } else { |
3201 | struct { |
3202 | u32 size; |
3203 | u32 data; |
3204 | } raw = { |
3205 | .size = sizeof(u32), |
3206 | .data = 0, |
3207 | }; |
3208 | perf_output_put(handle, raw); |
3209 | } |
3210 | } |
3211 | } |
3212 | |
3213 | void perf_prepare_sample(struct perf_event_header *header, |
3214 | struct perf_sample_data *data, |
3215 | struct perf_event *event, |
3216 | struct pt_regs *regs) |
3217 | { |
3218 | u64 sample_type = event->attr.sample_type; |
3219 | |
3220 | data->type = sample_type; |
3221 | |
3222 | header->type = PERF_RECORD_SAMPLE; |
3223 | header->size = sizeof(*header); |
3224 | |
3225 | header->misc = 0; |
3226 | header->misc |= perf_misc_flags(regs); |
3227 | |
3228 | if (sample_type & PERF_SAMPLE_IP) { |
3229 | data->ip = perf_instruction_pointer(regs); |
3230 | |
3231 | header->size += sizeof(data->ip); |
3232 | } |
3233 | |
3234 | if (sample_type & PERF_SAMPLE_TID) { |
3235 | /* namespace issues */ |
3236 | data->tid_entry.pid = perf_event_pid(event, current); |
3237 | data->tid_entry.tid = perf_event_tid(event, current); |
3238 | |
3239 | header->size += sizeof(data->tid_entry); |
3240 | } |
3241 | |
3242 | if (sample_type & PERF_SAMPLE_TIME) { |
3243 | data->time = perf_clock(); |
3244 | |
3245 | header->size += sizeof(data->time); |
3246 | } |
3247 | |
3248 | if (sample_type & PERF_SAMPLE_ADDR) |
3249 | header->size += sizeof(data->addr); |
3250 | |
3251 | if (sample_type & PERF_SAMPLE_ID) { |
3252 | data->id = primary_event_id(event); |
3253 | |
3254 | header->size += sizeof(data->id); |
3255 | } |
3256 | |
3257 | if (sample_type & PERF_SAMPLE_STREAM_ID) { |
3258 | data->stream_id = event->id; |
3259 | |
3260 | header->size += sizeof(data->stream_id); |
3261 | } |
3262 | |
3263 | if (sample_type & PERF_SAMPLE_CPU) { |
3264 | data->cpu_entry.cpu = raw_smp_processor_id(); |
3265 | data->cpu_entry.reserved = 0; |
3266 | |
3267 | header->size += sizeof(data->cpu_entry); |
3268 | } |
3269 | |
3270 | if (sample_type & PERF_SAMPLE_PERIOD) |
3271 | header->size += sizeof(data->period); |
3272 | |
3273 | if (sample_type & PERF_SAMPLE_READ) |
3274 | header->size += perf_event_read_size(event); |
3275 | |
3276 | if (sample_type & PERF_SAMPLE_CALLCHAIN) { |
3277 | int size = 1; |
3278 | |
3279 | data->callchain = perf_callchain(regs); |
3280 | |
3281 | if (data->callchain) |
3282 | size += data->callchain->nr; |
3283 | |
3284 | header->size += size * sizeof(u64); |
3285 | } |
3286 | |
3287 | if (sample_type & PERF_SAMPLE_RAW) { |
3288 | int size = sizeof(u32); |
3289 | |
3290 | if (data->raw) |
3291 | size += data->raw->size; |
3292 | else |
3293 | size += sizeof(u32); |
3294 | |
3295 | WARN_ON_ONCE(size & (sizeof(u64)-1)); |
3296 | header->size += size; |
3297 | } |
3298 | } |
3299 | |
3300 | static void perf_event_output(struct perf_event *event, int nmi, |
3301 | struct perf_sample_data *data, |
3302 | struct pt_regs *regs) |
3303 | { |
3304 | struct perf_output_handle handle; |
3305 | struct perf_event_header header; |
3306 | |
3307 | perf_prepare_sample(&header, data, event, regs); |
3308 | |
3309 | if (perf_output_begin(&handle, event, header.size, nmi, 1)) |
3310 | return; |
3311 | |
3312 | perf_output_sample(&handle, &header, data, event); |
3313 | |
3314 | perf_output_end(&handle); |
3315 | } |
3316 | |
3317 | /* |
3318 | * read event_id |
3319 | */ |
3320 | |
3321 | struct perf_read_event { |
3322 | struct perf_event_header header; |
3323 | |
3324 | u32 pid; |
3325 | u32 tid; |
3326 | }; |
3327 | |
3328 | static void |
3329 | perf_event_read_event(struct perf_event *event, |
3330 | struct task_struct *task) |
3331 | { |
3332 | struct perf_output_handle handle; |
3333 | struct perf_read_event read_event = { |
3334 | .header = { |
3335 | .type = PERF_RECORD_READ, |
3336 | .misc = 0, |
3337 | .size = sizeof(read_event) + perf_event_read_size(event), |
3338 | }, |
3339 | .pid = perf_event_pid(event, task), |
3340 | .tid = perf_event_tid(event, task), |
3341 | }; |
3342 | int ret; |
3343 | |
3344 | ret = perf_output_begin(&handle, event, read_event.header.size, 0, 0); |
3345 | if (ret) |
3346 | return; |
3347 | |
3348 | perf_output_put(&handle, read_event); |
3349 | perf_output_read(&handle, event); |
3350 | |
3351 | perf_output_end(&handle); |
3352 | } |
3353 | |
3354 | /* |
3355 | * task tracking -- fork/exit |
3356 | * |
3357 | * enabled by: attr.comm | attr.mmap | attr.task |
3358 | */ |
3359 | |
3360 | struct perf_task_event { |
3361 | struct task_struct *task; |
3362 | struct perf_event_context *task_ctx; |
3363 | |
3364 | struct { |
3365 | struct perf_event_header header; |
3366 | |
3367 | u32 pid; |
3368 | u32 ppid; |
3369 | u32 tid; |
3370 | u32 ptid; |
3371 | u64 time; |
3372 | } event_id; |
3373 | }; |
3374 | |
3375 | static void perf_event_task_output(struct perf_event *event, |
3376 | struct perf_task_event *task_event) |
3377 | { |
3378 | struct perf_output_handle handle; |
3379 | struct task_struct *task = task_event->task; |
3380 | unsigned long flags; |
3381 | int size, ret; |
3382 | |
3383 | /* |
3384 | * If this CPU attempts to acquire an rq lock held by a CPU spinning |
3385 | * in perf_output_lock() from interrupt context, it's game over. |
3386 | */ |
3387 | local_irq_save(flags); |
3388 | |
3389 | size = task_event->event_id.header.size; |
3390 | ret = perf_output_begin(&handle, event, size, 0, 0); |
3391 | |
3392 | if (ret) { |
3393 | local_irq_restore(flags); |
3394 | return; |
3395 | } |
3396 | |
3397 | task_event->event_id.pid = perf_event_pid(event, task); |
3398 | task_event->event_id.ppid = perf_event_pid(event, current); |
3399 | |
3400 | task_event->event_id.tid = perf_event_tid(event, task); |
3401 | task_event->event_id.ptid = perf_event_tid(event, current); |
3402 | |
3403 | perf_output_put(&handle, task_event->event_id); |
3404 | |
3405 | perf_output_end(&handle); |
3406 | local_irq_restore(flags); |
3407 | } |
3408 | |
3409 | static int perf_event_task_match(struct perf_event *event) |
3410 | { |
3411 | if (event->state < PERF_EVENT_STATE_INACTIVE) |
3412 | return 0; |
3413 | |
3414 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
3415 | return 0; |
3416 | |
3417 | if (event->attr.comm || event->attr.mmap || event->attr.task) |
3418 | return 1; |
3419 | |
3420 | return 0; |
3421 | } |
3422 | |
3423 | static void perf_event_task_ctx(struct perf_event_context *ctx, |
3424 | struct perf_task_event *task_event) |
3425 | { |
3426 | struct perf_event *event; |
3427 | |
3428 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
3429 | if (perf_event_task_match(event)) |
3430 | perf_event_task_output(event, task_event); |
3431 | } |
3432 | } |
3433 | |
3434 | static void perf_event_task_event(struct perf_task_event *task_event) |
3435 | { |
3436 | struct perf_cpu_context *cpuctx; |
3437 | struct perf_event_context *ctx = task_event->task_ctx; |
3438 | |
3439 | rcu_read_lock(); |
3440 | cpuctx = &get_cpu_var(perf_cpu_context); |
3441 | perf_event_task_ctx(&cpuctx->ctx, task_event); |
3442 | if (!ctx) |
3443 | ctx = rcu_dereference(current->perf_event_ctxp); |
3444 | if (ctx) |
3445 | perf_event_task_ctx(ctx, task_event); |
3446 | put_cpu_var(perf_cpu_context); |
3447 | rcu_read_unlock(); |
3448 | } |
3449 | |
3450 | static void perf_event_task(struct task_struct *task, |
3451 | struct perf_event_context *task_ctx, |
3452 | int new) |
3453 | { |
3454 | struct perf_task_event task_event; |
3455 | |
3456 | if (!atomic_read(&nr_comm_events) && |
3457 | !atomic_read(&nr_mmap_events) && |
3458 | !atomic_read(&nr_task_events)) |
3459 | return; |
3460 | |
3461 | task_event = (struct perf_task_event){ |
3462 | .task = task, |
3463 | .task_ctx = task_ctx, |
3464 | .event_id = { |
3465 | .header = { |
3466 | .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, |
3467 | .misc = 0, |
3468 | .size = sizeof(task_event.event_id), |
3469 | }, |
3470 | /* .pid */ |
3471 | /* .ppid */ |
3472 | /* .tid */ |
3473 | /* .ptid */ |
3474 | .time = perf_clock(), |
3475 | }, |
3476 | }; |
3477 | |
3478 | perf_event_task_event(&task_event); |
3479 | } |
3480 | |
3481 | void perf_event_fork(struct task_struct *task) |
3482 | { |
3483 | perf_event_task(task, NULL, 1); |
3484 | } |
3485 | |
3486 | /* |
3487 | * comm tracking |
3488 | */ |
3489 | |
3490 | struct perf_comm_event { |
3491 | struct task_struct *task; |
3492 | char *comm; |
3493 | int comm_size; |
3494 | |
3495 | struct { |
3496 | struct perf_event_header header; |
3497 | |
3498 | u32 pid; |
3499 | u32 tid; |
3500 | } event_id; |
3501 | }; |
3502 | |
3503 | static void perf_event_comm_output(struct perf_event *event, |
3504 | struct perf_comm_event *comm_event) |
3505 | { |
3506 | struct perf_output_handle handle; |
3507 | int size = comm_event->event_id.header.size; |
3508 | int ret = perf_output_begin(&handle, event, size, 0, 0); |
3509 | |
3510 | if (ret) |
3511 | return; |
3512 | |
3513 | comm_event->event_id.pid = perf_event_pid(event, comm_event->task); |
3514 | comm_event->event_id.tid = perf_event_tid(event, comm_event->task); |
3515 | |
3516 | perf_output_put(&handle, comm_event->event_id); |
3517 | perf_output_copy(&handle, comm_event->comm, |
3518 | comm_event->comm_size); |
3519 | perf_output_end(&handle); |
3520 | } |
3521 | |
3522 | static int perf_event_comm_match(struct perf_event *event) |
3523 | { |
3524 | if (event->state < PERF_EVENT_STATE_INACTIVE) |
3525 | return 0; |
3526 | |
3527 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
3528 | return 0; |
3529 | |
3530 | if (event->attr.comm) |
3531 | return 1; |
3532 | |
3533 | return 0; |
3534 | } |
3535 | |
3536 | static void perf_event_comm_ctx(struct perf_event_context *ctx, |
3537 | struct perf_comm_event *comm_event) |
3538 | { |
3539 | struct perf_event *event; |
3540 | |
3541 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
3542 | if (perf_event_comm_match(event)) |
3543 | perf_event_comm_output(event, comm_event); |
3544 | } |
3545 | } |
3546 | |
3547 | static void perf_event_comm_event(struct perf_comm_event *comm_event) |
3548 | { |
3549 | struct perf_cpu_context *cpuctx; |
3550 | struct perf_event_context *ctx; |
3551 | unsigned int size; |
3552 | char comm[TASK_COMM_LEN]; |
3553 | |
3554 | memset(comm, 0, sizeof(comm)); |
3555 | strlcpy(comm, comm_event->task->comm, sizeof(comm)); |
3556 | size = ALIGN(strlen(comm)+1, sizeof(u64)); |
3557 | |
3558 | comm_event->comm = comm; |
3559 | comm_event->comm_size = size; |
3560 | |
3561 | comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; |
3562 | |
3563 | rcu_read_lock(); |
3564 | cpuctx = &get_cpu_var(perf_cpu_context); |
3565 | perf_event_comm_ctx(&cpuctx->ctx, comm_event); |
3566 | ctx = rcu_dereference(current->perf_event_ctxp); |
3567 | if (ctx) |
3568 | perf_event_comm_ctx(ctx, comm_event); |
3569 | put_cpu_var(perf_cpu_context); |
3570 | rcu_read_unlock(); |
3571 | } |
3572 | |
3573 | void perf_event_comm(struct task_struct *task) |
3574 | { |
3575 | struct perf_comm_event comm_event; |
3576 | |
3577 | if (task->perf_event_ctxp) |
3578 | perf_event_enable_on_exec(task); |
3579 | |
3580 | if (!atomic_read(&nr_comm_events)) |
3581 | return; |
3582 | |
3583 | comm_event = (struct perf_comm_event){ |
3584 | .task = task, |
3585 | /* .comm */ |
3586 | /* .comm_size */ |
3587 | .event_id = { |
3588 | .header = { |
3589 | .type = PERF_RECORD_COMM, |
3590 | .misc = 0, |
3591 | /* .size */ |
3592 | }, |
3593 | /* .pid */ |
3594 | /* .tid */ |
3595 | }, |
3596 | }; |
3597 | |
3598 | perf_event_comm_event(&comm_event); |
3599 | } |
3600 | |
3601 | /* |
3602 | * mmap tracking |
3603 | */ |
3604 | |
3605 | struct perf_mmap_event { |
3606 | struct vm_area_struct *vma; |
3607 | |
3608 | const char *file_name; |
3609 | int file_size; |
3610 | |
3611 | struct { |
3612 | struct perf_event_header header; |
3613 | |
3614 | u32 pid; |
3615 | u32 tid; |
3616 | u64 start; |
3617 | u64 len; |
3618 | u64 pgoff; |
3619 | } event_id; |
3620 | }; |
3621 | |
3622 | static void perf_event_mmap_output(struct perf_event *event, |
3623 | struct perf_mmap_event *mmap_event) |
3624 | { |
3625 | struct perf_output_handle handle; |
3626 | int size = mmap_event->event_id.header.size; |
3627 | int ret = perf_output_begin(&handle, event, size, 0, 0); |
3628 | |
3629 | if (ret) |
3630 | return; |
3631 | |
3632 | mmap_event->event_id.pid = perf_event_pid(event, current); |
3633 | mmap_event->event_id.tid = perf_event_tid(event, current); |
3634 | |
3635 | perf_output_put(&handle, mmap_event->event_id); |
3636 | perf_output_copy(&handle, mmap_event->file_name, |
3637 | mmap_event->file_size); |
3638 | perf_output_end(&handle); |
3639 | } |
3640 | |
3641 | static int perf_event_mmap_match(struct perf_event *event, |
3642 | struct perf_mmap_event *mmap_event) |
3643 | { |
3644 | if (event->state < PERF_EVENT_STATE_INACTIVE) |
3645 | return 0; |
3646 | |
3647 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
3648 | return 0; |
3649 | |
3650 | if (event->attr.mmap) |
3651 | return 1; |
3652 | |
3653 | return 0; |
3654 | } |
3655 | |
3656 | static void perf_event_mmap_ctx(struct perf_event_context *ctx, |
3657 | struct perf_mmap_event *mmap_event) |
3658 | { |
3659 | struct perf_event *event; |
3660 | |
3661 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
3662 | if (perf_event_mmap_match(event, mmap_event)) |
3663 | perf_event_mmap_output(event, mmap_event); |
3664 | } |
3665 | } |
3666 | |
3667 | static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) |
3668 | { |
3669 | struct perf_cpu_context *cpuctx; |
3670 | struct perf_event_context *ctx; |
3671 | struct vm_area_struct *vma = mmap_event->vma; |
3672 | struct file *file = vma->vm_file; |
3673 | unsigned int size; |
3674 | char tmp[16]; |
3675 | char *buf = NULL; |
3676 | const char *name; |
3677 | |
3678 | memset(tmp, 0, sizeof(tmp)); |
3679 | |
3680 | if (file) { |
3681 | /* |
3682 | * d_path works from the end of the buffer backwards, so we |
3683 | * need to add enough zero bytes after the string to handle |
3684 | * the 64bit alignment we do later. |
3685 | */ |
3686 | buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL); |
3687 | if (!buf) { |
3688 | name = strncpy(tmp, "//enomem", sizeof(tmp)); |
3689 | goto got_name; |
3690 | } |
3691 | name = d_path(&file->f_path, buf, PATH_MAX); |
3692 | if (IS_ERR(name)) { |
3693 | name = strncpy(tmp, "//toolong", sizeof(tmp)); |
3694 | goto got_name; |
3695 | } |
3696 | } else { |
3697 | if (arch_vma_name(mmap_event->vma)) { |
3698 | name = strncpy(tmp, arch_vma_name(mmap_event->vma), |
3699 | sizeof(tmp)); |
3700 | goto got_name; |
3701 | } |
3702 | |
3703 | if (!vma->vm_mm) { |
3704 | name = strncpy(tmp, "[vdso]", sizeof(tmp)); |
3705 | goto got_name; |
3706 | } |
3707 | |
3708 | name = strncpy(tmp, "//anon", sizeof(tmp)); |
3709 | goto got_name; |
3710 | } |
3711 | |
3712 | got_name: |
3713 | size = ALIGN(strlen(name)+1, sizeof(u64)); |
3714 | |
3715 | mmap_event->file_name = name; |
3716 | mmap_event->file_size = size; |
3717 | |
3718 | mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; |
3719 | |
3720 | rcu_read_lock(); |
3721 | cpuctx = &get_cpu_var(perf_cpu_context); |
3722 | perf_event_mmap_ctx(&cpuctx->ctx, mmap_event); |
3723 | ctx = rcu_dereference(current->perf_event_ctxp); |
3724 | if (ctx) |
3725 | perf_event_mmap_ctx(ctx, mmap_event); |
3726 | put_cpu_var(perf_cpu_context); |
3727 | rcu_read_unlock(); |
3728 | |
3729 | kfree(buf); |
3730 | } |
3731 | |
3732 | void __perf_event_mmap(struct vm_area_struct *vma) |
3733 | { |
3734 | struct perf_mmap_event mmap_event; |
3735 | |
3736 | if (!atomic_read(&nr_mmap_events)) |
3737 | return; |
3738 | |
3739 | mmap_event = (struct perf_mmap_event){ |
3740 | .vma = vma, |
3741 | /* .file_name */ |
3742 | /* .file_size */ |
3743 | .event_id = { |
3744 | .header = { |
3745 | .type = PERF_RECORD_MMAP, |
3746 | .misc = 0, |
3747 | /* .size */ |
3748 | }, |
3749 | /* .pid */ |
3750 | /* .tid */ |
3751 | .start = vma->vm_start, |
3752 | .len = vma->vm_end - vma->vm_start, |
3753 | .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, |
3754 | }, |
3755 | }; |
3756 | |
3757 | perf_event_mmap_event(&mmap_event); |
3758 | } |
3759 | |
3760 | /* |
3761 | * IRQ throttle logging |
3762 | */ |
3763 | |
3764 | static void perf_log_throttle(struct perf_event *event, int enable) |
3765 | { |
3766 | struct perf_output_handle handle; |
3767 | int ret; |
3768 | |
3769 | struct { |
3770 | struct perf_event_header header; |
3771 | u64 time; |
3772 | u64 id; |
3773 | u64 stream_id; |
3774 | } throttle_event = { |
3775 | .header = { |
3776 | .type = PERF_RECORD_THROTTLE, |
3777 | .misc = 0, |
3778 | .size = sizeof(throttle_event), |
3779 | }, |
3780 | .time = perf_clock(), |
3781 | .id = primary_event_id(event), |
3782 | .stream_id = event->id, |
3783 | }; |
3784 | |
3785 | if (enable) |
3786 | throttle_event.header.type = PERF_RECORD_UNTHROTTLE; |
3787 | |
3788 | ret = perf_output_begin(&handle, event, sizeof(throttle_event), 1, 0); |
3789 | if (ret) |
3790 | return; |
3791 | |
3792 | perf_output_put(&handle, throttle_event); |
3793 | perf_output_end(&handle); |
3794 | } |
3795 | |
3796 | /* |
3797 | * Generic event overflow handling, sampling. |
3798 | */ |
3799 | |
3800 | static int __perf_event_overflow(struct perf_event *event, int nmi, |
3801 | int throttle, struct perf_sample_data *data, |
3802 | struct pt_regs *regs) |
3803 | { |
3804 | int events = atomic_read(&event->event_limit); |
3805 | struct hw_perf_event *hwc = &event->hw; |
3806 | int ret = 0; |
3807 | |
3808 | throttle = (throttle && event->pmu->unthrottle != NULL); |
3809 | |
3810 | if (!throttle) { |
3811 | hwc->interrupts++; |
3812 | } else { |
3813 | if (hwc->interrupts != MAX_INTERRUPTS) { |
3814 | hwc->interrupts++; |
3815 | if (HZ * hwc->interrupts > |
3816 | (u64)sysctl_perf_event_sample_rate) { |
3817 | hwc->interrupts = MAX_INTERRUPTS; |
3818 | perf_log_throttle(event, 0); |
3819 | ret = 1; |
3820 | } |
3821 | } else { |
3822 | /* |
3823 | * Keep re-disabling events even though on the previous |
3824 | * pass we disabled it - just in case we raced with a |
3825 | * sched-in and the event got enabled again: |
3826 | */ |
3827 | ret = 1; |
3828 | } |
3829 | } |
3830 | |
3831 | if (event->attr.freq) { |
3832 | u64 now = perf_clock(); |
3833 | s64 delta = now - hwc->freq_time_stamp; |
3834 | |
3835 | hwc->freq_time_stamp = now; |
3836 | |
3837 | if (delta > 0 && delta < 2*TICK_NSEC) |
3838 | perf_adjust_period(event, delta, hwc->last_period); |
3839 | } |
3840 | |
3841 | /* |
3842 | * XXX event_limit might not quite work as expected on inherited |
3843 | * events |
3844 | */ |
3845 | |
3846 | event->pending_kill = POLL_IN; |
3847 | if (events && atomic_dec_and_test(&event->event_limit)) { |
3848 | ret = 1; |
3849 | event->pending_kill = POLL_HUP; |
3850 | if (nmi) { |
3851 | event->pending_disable = 1; |
3852 | perf_pending_queue(&event->pending, |
3853 | perf_pending_event); |
3854 | } else |
3855 | perf_event_disable(event); |
3856 | } |
3857 | |
3858 | if (event->overflow_handler) |
3859 | event->overflow_handler(event, nmi, data, regs); |
3860 | else |
3861 | perf_event_output(event, nmi, data, regs); |
3862 | |
3863 | return ret; |
3864 | } |
3865 | |
3866 | int perf_event_overflow(struct perf_event *event, int nmi, |
3867 | struct perf_sample_data *data, |
3868 | struct pt_regs *regs) |
3869 | { |
3870 | return __perf_event_overflow(event, nmi, 1, data, regs); |
3871 | } |
3872 | |
3873 | /* |
3874 | * Generic software event infrastructure |
3875 | */ |
3876 | |
3877 | /* |
3878 | * We directly increment event->count and keep a second value in |
3879 | * event->hw.period_left to count intervals. This period event |
3880 | * is kept in the range [-sample_period, 0] so that we can use the |
3881 | * sign as trigger. |
3882 | */ |
3883 | |
3884 | static u64 perf_swevent_set_period(struct perf_event *event) |
3885 | { |
3886 | struct hw_perf_event *hwc = &event->hw; |
3887 | u64 period = hwc->last_period; |
3888 | u64 nr, offset; |
3889 | s64 old, val; |
3890 | |
3891 | hwc->last_period = hwc->sample_period; |
3892 | |
3893 | again: |
3894 | old = val = atomic64_read(&hwc->period_left); |
3895 | if (val < 0) |
3896 | return 0; |
3897 | |
3898 | nr = div64_u64(period + val, period); |
3899 | offset = nr * period; |
3900 | val -= offset; |
3901 | if (atomic64_cmpxchg(&hwc->period_left, old, val) != old) |
3902 | goto again; |
3903 | |
3904 | return nr; |
3905 | } |
3906 | |
3907 | static void perf_swevent_overflow(struct perf_event *event, u64 overflow, |
3908 | int nmi, struct perf_sample_data *data, |
3909 | struct pt_regs *regs) |
3910 | { |
3911 | struct hw_perf_event *hwc = &event->hw; |
3912 | int throttle = 0; |
3913 | |
3914 | data->period = event->hw.last_period; |
3915 | if (!overflow) |
3916 | overflow = perf_swevent_set_period(event); |
3917 | |
3918 | if (hwc->interrupts == MAX_INTERRUPTS) |
3919 | return; |
3920 | |
3921 | for (; overflow; overflow--) { |
3922 | if (__perf_event_overflow(event, nmi, throttle, |
3923 | data, regs)) { |
3924 | /* |
3925 | * We inhibit the overflow from happening when |
3926 | * hwc->interrupts == MAX_INTERRUPTS. |
3927 | */ |
3928 | break; |
3929 | } |
3930 | throttle = 1; |
3931 | } |
3932 | } |
3933 | |
3934 | static void perf_swevent_unthrottle(struct perf_event *event) |
3935 | { |
3936 | /* |
3937 | * Nothing to do, we already reset hwc->interrupts. |
3938 | */ |
3939 | } |
3940 | |
3941 | static void perf_swevent_add(struct perf_event *event, u64 nr, |
3942 | int nmi, struct perf_sample_data *data, |
3943 | struct pt_regs *regs) |
3944 | { |
3945 | struct hw_perf_event *hwc = &event->hw; |
3946 | |
3947 | atomic64_add(nr, &event->count); |
3948 | |
3949 | if (!regs) |
3950 | return; |
3951 | |
3952 | if (!hwc->sample_period) |
3953 | return; |
3954 | |
3955 | if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) |
3956 | return perf_swevent_overflow(event, 1, nmi, data, regs); |
3957 | |
3958 | if (atomic64_add_negative(nr, &hwc->period_left)) |
3959 | return; |
3960 | |
3961 | perf_swevent_overflow(event, 0, nmi, data, regs); |
3962 | } |
3963 | |
3964 | static int perf_swevent_is_counting(struct perf_event *event) |
3965 | { |
3966 | /* |
3967 | * The event is active, we're good! |
3968 | */ |
3969 | if (event->state == PERF_EVENT_STATE_ACTIVE) |
3970 | return 1; |
3971 | |
3972 | /* |
3973 | * The event is off/error, not counting. |
3974 | */ |
3975 | if (event->state != PERF_EVENT_STATE_INACTIVE) |
3976 | return 0; |
3977 | |
3978 | /* |
3979 | * The event is inactive, if the context is active |
3980 | * we're part of a group that didn't make it on the 'pmu', |
3981 | * not counting. |
3982 | */ |
3983 | if (event->ctx->is_active) |
3984 | return 0; |
3985 | |
3986 | /* |
3987 | * We're inactive and the context is too, this means the |
3988 | * task is scheduled out, we're counting events that happen |
3989 | * to us, like migration events. |
3990 | */ |
3991 | return 1; |
3992 | } |
3993 | |
3994 | static int perf_tp_event_match(struct perf_event *event, |
3995 | struct perf_sample_data *data); |
3996 | |
3997 | static int perf_exclude_event(struct perf_event *event, |
3998 | struct pt_regs *regs) |
3999 | { |
4000 | if (regs) { |
4001 | if (event->attr.exclude_user && user_mode(regs)) |
4002 | return 1; |
4003 | |
4004 | if (event->attr.exclude_kernel && !user_mode(regs)) |
4005 | return 1; |
4006 | } |
4007 | |
4008 | return 0; |
4009 | } |
4010 | |
4011 | static int perf_swevent_match(struct perf_event *event, |
4012 | enum perf_type_id type, |
4013 | u32 event_id, |
4014 | struct perf_sample_data *data, |
4015 | struct pt_regs *regs) |
4016 | { |
4017 | if (event->cpu != -1 && event->cpu != smp_processor_id()) |
4018 | return 0; |
4019 | |
4020 | if (!perf_swevent_is_counting(event)) |
4021 | return 0; |
4022 | |
4023 | if (event->attr.type != type) |
4024 | return 0; |
4025 | |
4026 | if (event->attr.config != event_id) |
4027 | return 0; |
4028 | |
4029 | if (perf_exclude_event(event, regs)) |
4030 | return 0; |
4031 | |
4032 | if (event->attr.type == PERF_TYPE_TRACEPOINT && |
4033 | !perf_tp_event_match(event, data)) |
4034 | return 0; |
4035 | |
4036 | return 1; |
4037 | } |
4038 | |
4039 | static void perf_swevent_ctx_event(struct perf_event_context *ctx, |
4040 | enum perf_type_id type, |
4041 | u32 event_id, u64 nr, int nmi, |
4042 | struct perf_sample_data *data, |
4043 | struct pt_regs *regs) |
4044 | { |
4045 | struct perf_event *event; |
4046 | |
4047 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { |
4048 | if (perf_swevent_match(event, type, event_id, data, regs)) |
4049 | perf_swevent_add(event, nr, nmi, data, regs); |
4050 | } |
4051 | } |
4052 | |
4053 | int perf_swevent_get_recursion_context(void) |
4054 | { |
4055 | struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context); |
4056 | int rctx; |
4057 | |
4058 | if (in_nmi()) |
4059 | rctx = 3; |
4060 | else if (in_irq()) |
4061 | rctx = 2; |
4062 | else if (in_softirq()) |
4063 | rctx = 1; |
4064 | else |
4065 | rctx = 0; |
4066 | |
4067 | if (cpuctx->recursion[rctx]) { |
4068 | put_cpu_var(perf_cpu_context); |
4069 | return -1; |
4070 | } |
4071 | |
4072 | cpuctx->recursion[rctx]++; |
4073 | barrier(); |
4074 | |
4075 | return rctx; |
4076 | } |
4077 | EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); |
4078 | |
4079 | void perf_swevent_put_recursion_context(int rctx) |
4080 | { |
4081 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
4082 | barrier(); |
4083 | cpuctx->recursion[rctx]--; |
4084 | put_cpu_var(perf_cpu_context); |
4085 | } |
4086 | EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context); |
4087 | |
4088 | static void do_perf_sw_event(enum perf_type_id type, u32 event_id, |
4089 | u64 nr, int nmi, |
4090 | struct perf_sample_data *data, |
4091 | struct pt_regs *regs) |
4092 | { |
4093 | struct perf_cpu_context *cpuctx; |
4094 | struct perf_event_context *ctx; |
4095 | |
4096 | cpuctx = &__get_cpu_var(perf_cpu_context); |
4097 | rcu_read_lock(); |
4098 | perf_swevent_ctx_event(&cpuctx->ctx, type, event_id, |
4099 | nr, nmi, data, regs); |
4100 | /* |
4101 | * doesn't really matter which of the child contexts the |
4102 | * events ends up in. |
4103 | */ |
4104 | ctx = rcu_dereference(current->perf_event_ctxp); |
4105 | if (ctx) |
4106 | perf_swevent_ctx_event(ctx, type, event_id, nr, nmi, data, regs); |
4107 | rcu_read_unlock(); |
4108 | } |
4109 | |
4110 | void __perf_sw_event(u32 event_id, u64 nr, int nmi, |
4111 | struct pt_regs *regs, u64 addr) |
4112 | { |
4113 | struct perf_sample_data data; |
4114 | int rctx; |
4115 | |
4116 | rctx = perf_swevent_get_recursion_context(); |
4117 | if (rctx < 0) |
4118 | return; |
4119 | |
4120 | perf_sample_data_init(&data, addr); |
4121 | |
4122 | do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs); |
4123 | |
4124 | perf_swevent_put_recursion_context(rctx); |
4125 | } |
4126 | |
4127 | static void perf_swevent_read(struct perf_event *event) |
4128 | { |
4129 | } |
4130 | |
4131 | static int perf_swevent_enable(struct perf_event *event) |
4132 | { |
4133 | struct hw_perf_event *hwc = &event->hw; |
4134 | |
4135 | if (hwc->sample_period) { |
4136 | hwc->last_period = hwc->sample_period; |
4137 | perf_swevent_set_period(event); |
4138 | } |
4139 | return 0; |
4140 | } |
4141 | |
4142 | static void perf_swevent_disable(struct perf_event *event) |
4143 | { |
4144 | } |
4145 | |
4146 | static const struct pmu perf_ops_generic = { |
4147 | .enable = perf_swevent_enable, |
4148 | .disable = perf_swevent_disable, |
4149 | .read = perf_swevent_read, |
4150 | .unthrottle = perf_swevent_unthrottle, |
4151 | }; |
4152 | |
4153 | /* |
4154 | * hrtimer based swevent callback |
4155 | */ |
4156 | |
4157 | static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) |
4158 | { |
4159 | enum hrtimer_restart ret = HRTIMER_RESTART; |
4160 | struct perf_sample_data data; |
4161 | struct pt_regs *regs; |
4162 | struct perf_event *event; |
4163 | u64 period; |
4164 | |
4165 | event = container_of(hrtimer, struct perf_event, hw.hrtimer); |
4166 | event->pmu->read(event); |
4167 | |
4168 | perf_sample_data_init(&data, 0); |
4169 | data.period = event->hw.last_period; |
4170 | regs = get_irq_regs(); |
4171 | /* |
4172 | * In case we exclude kernel IPs or are somehow not in interrupt |
4173 | * context, provide the next best thing, the user IP. |
4174 | */ |
4175 | if ((event->attr.exclude_kernel || !regs) && |
4176 | !event->attr.exclude_user) |
4177 | regs = task_pt_regs(current); |
4178 | |
4179 | if (regs) { |
4180 | if (!(event->attr.exclude_idle && current->pid == 0)) |
4181 | if (perf_event_overflow(event, 0, &data, regs)) |
4182 | ret = HRTIMER_NORESTART; |
4183 | } |
4184 | |
4185 | period = max_t(u64, 10000, event->hw.sample_period); |
4186 | hrtimer_forward_now(hrtimer, ns_to_ktime(period)); |
4187 | |
4188 | return ret; |
4189 | } |
4190 | |
4191 | static void perf_swevent_start_hrtimer(struct perf_event *event) |
4192 | { |
4193 | struct hw_perf_event *hwc = &event->hw; |
4194 | |
4195 | hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
4196 | hwc->hrtimer.function = perf_swevent_hrtimer; |
4197 | if (hwc->sample_period) { |
4198 | u64 period; |
4199 | |
4200 | if (hwc->remaining) { |
4201 | if (hwc->remaining < 0) |
4202 | period = 10000; |
4203 | else |
4204 | period = hwc->remaining; |
4205 | hwc->remaining = 0; |
4206 | } else { |
4207 | period = max_t(u64, 10000, hwc->sample_period); |
4208 | } |
4209 | __hrtimer_start_range_ns(&hwc->hrtimer, |
4210 | ns_to_ktime(period), 0, |
4211 | HRTIMER_MODE_REL, 0); |
4212 | } |
4213 | } |
4214 | |
4215 | static void perf_swevent_cancel_hrtimer(struct perf_event *event) |
4216 | { |
4217 | struct hw_perf_event *hwc = &event->hw; |
4218 | |
4219 | if (hwc->sample_period) { |
4220 | ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); |
4221 | hwc->remaining = ktime_to_ns(remaining); |
4222 | |
4223 | hrtimer_cancel(&hwc->hrtimer); |
4224 | } |
4225 | } |
4226 | |
4227 | /* |
4228 | * Software event: cpu wall time clock |
4229 | */ |
4230 | |
4231 | static void cpu_clock_perf_event_update(struct perf_event *event) |
4232 | { |
4233 | int cpu = raw_smp_processor_id(); |
4234 | s64 prev; |
4235 | u64 now; |
4236 | |
4237 | now = cpu_clock(cpu); |
4238 | prev = atomic64_xchg(&event->hw.prev_count, now); |
4239 | atomic64_add(now - prev, &event->count); |
4240 | } |
4241 | |
4242 | static int cpu_clock_perf_event_enable(struct perf_event *event) |
4243 | { |
4244 | struct hw_perf_event *hwc = &event->hw; |
4245 | int cpu = raw_smp_processor_id(); |
4246 | |
4247 | atomic64_set(&hwc->prev_count, cpu_clock(cpu)); |
4248 | perf_swevent_start_hrtimer(event); |
4249 | |
4250 | return 0; |
4251 | } |
4252 | |
4253 | static void cpu_clock_perf_event_disable(struct perf_event *event) |
4254 | { |
4255 | perf_swevent_cancel_hrtimer(event); |
4256 | cpu_clock_perf_event_update(event); |
4257 | } |
4258 | |
4259 | static void cpu_clock_perf_event_read(struct perf_event *event) |
4260 | { |
4261 | cpu_clock_perf_event_update(event); |
4262 | } |
4263 | |
4264 | static const struct pmu perf_ops_cpu_clock = { |
4265 | .enable = cpu_clock_perf_event_enable, |
4266 | .disable = cpu_clock_perf_event_disable, |
4267 | .read = cpu_clock_perf_event_read, |
4268 | }; |
4269 | |
4270 | /* |
4271 | * Software event: task time clock |
4272 | */ |
4273 | |
4274 | static void task_clock_perf_event_update(struct perf_event *event, u64 now) |
4275 | { |
4276 | u64 prev; |
4277 | s64 delta; |
4278 | |
4279 | prev = atomic64_xchg(&event->hw.prev_count, now); |
4280 | delta = now - prev; |
4281 | atomic64_add(delta, &event->count); |
4282 | } |
4283 | |
4284 | static int task_clock_perf_event_enable(struct perf_event *event) |
4285 | { |
4286 | struct hw_perf_event *hwc = &event->hw; |
4287 | u64 now; |
4288 | |
4289 | now = event->ctx->time; |
4290 | |
4291 | atomic64_set(&hwc->prev_count, now); |
4292 | |
4293 | perf_swevent_start_hrtimer(event); |
4294 | |
4295 | return 0; |
4296 | } |
4297 | |
4298 | static void task_clock_perf_event_disable(struct perf_event *event) |
4299 | { |
4300 | perf_swevent_cancel_hrtimer(event); |
4301 | task_clock_perf_event_update(event, event->ctx->time); |
4302 | |
4303 | } |
4304 | |
4305 | static void task_clock_perf_event_read(struct perf_event *event) |
4306 | { |
4307 | u64 time; |
4308 | |
4309 | if (!in_nmi()) { |
4310 | update_context_time(event->ctx); |
4311 | time = event->ctx->time; |
4312 | } else { |
4313 | u64 now = perf_clock(); |
4314 | u64 delta = now - event->ctx->timestamp; |
4315 | time = event->ctx->time + delta; |
4316 | } |
4317 | |
4318 | task_clock_perf_event_update(event, time); |
4319 | } |
4320 | |
4321 | static const struct pmu perf_ops_task_clock = { |
4322 | .enable = task_clock_perf_event_enable, |
4323 | .disable = task_clock_perf_event_disable, |
4324 | .read = task_clock_perf_event_read, |
4325 | }; |
4326 | |
4327 | #ifdef CONFIG_EVENT_TRACING |
4328 | |
4329 | void perf_tp_event(int event_id, u64 addr, u64 count, void *record, |
4330 | int entry_size, struct pt_regs *regs) |
4331 | { |
4332 | struct perf_sample_data data; |
4333 | struct perf_raw_record raw = { |
4334 | .size = entry_size, |
4335 | .data = record, |
4336 | }; |
4337 | |
4338 | perf_sample_data_init(&data, addr); |
4339 | data.raw = &raw; |
4340 | |
4341 | /* Trace events already protected against recursion */ |
4342 | do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1, |
4343 | &data, regs); |
4344 | } |
4345 | EXPORT_SYMBOL_GPL(perf_tp_event); |
4346 | |
4347 | static int perf_tp_event_match(struct perf_event *event, |
4348 | struct perf_sample_data *data) |
4349 | { |
4350 | void *record = data->raw->data; |
4351 | |
4352 | if (likely(!event->filter) || filter_match_preds(event->filter, record)) |
4353 | return 1; |
4354 | return 0; |
4355 | } |
4356 | |
4357 | static void tp_perf_event_destroy(struct perf_event *event) |
4358 | { |
4359 | perf_trace_disable(event->attr.config); |
4360 | } |
4361 | |
4362 | static const struct pmu *tp_perf_event_init(struct perf_event *event) |
4363 | { |
4364 | /* |
4365 | * Raw tracepoint data is a severe data leak, only allow root to |
4366 | * have these. |
4367 | */ |
4368 | if ((event->attr.sample_type & PERF_SAMPLE_RAW) && |
4369 | perf_paranoid_tracepoint_raw() && |
4370 | !capable(CAP_SYS_ADMIN)) |
4371 | return ERR_PTR(-EPERM); |
4372 | |
4373 | if (perf_trace_enable(event->attr.config)) |
4374 | return NULL; |
4375 | |
4376 | event->destroy = tp_perf_event_destroy; |
4377 | |
4378 | return &perf_ops_generic; |
4379 | } |
4380 | |
4381 | static int perf_event_set_filter(struct perf_event *event, void __user *arg) |
4382 | { |
4383 | char *filter_str; |
4384 | int ret; |
4385 | |
4386 | if (event->attr.type != PERF_TYPE_TRACEPOINT) |
4387 | return -EINVAL; |
4388 | |
4389 | filter_str = strndup_user(arg, PAGE_SIZE); |
4390 | if (IS_ERR(filter_str)) |
4391 | return PTR_ERR(filter_str); |
4392 | |
4393 | ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); |
4394 | |
4395 | kfree(filter_str); |
4396 | return ret; |
4397 | } |
4398 | |
4399 | static void perf_event_free_filter(struct perf_event *event) |
4400 | { |
4401 | ftrace_profile_free_filter(event); |
4402 | } |
4403 | |
4404 | #else |
4405 | |
4406 | static int perf_tp_event_match(struct perf_event *event, |
4407 | struct perf_sample_data *data) |
4408 | { |
4409 | return 1; |
4410 | } |
4411 | |
4412 | static const struct pmu *tp_perf_event_init(struct perf_event *event) |
4413 | { |
4414 | return NULL; |
4415 | } |
4416 | |
4417 | static int perf_event_set_filter(struct perf_event *event, void __user *arg) |
4418 | { |
4419 | return -ENOENT; |
4420 | } |
4421 | |
4422 | static void perf_event_free_filter(struct perf_event *event) |
4423 | { |
4424 | } |
4425 | |
4426 | #endif /* CONFIG_EVENT_TRACING */ |
4427 | |
4428 | #ifdef CONFIG_HAVE_HW_BREAKPOINT |
4429 | static void bp_perf_event_destroy(struct perf_event *event) |
4430 | { |
4431 | release_bp_slot(event); |
4432 | } |
4433 | |
4434 | static const struct pmu *bp_perf_event_init(struct perf_event *bp) |
4435 | { |
4436 | int err; |
4437 | |
4438 | err = register_perf_hw_breakpoint(bp); |
4439 | if (err) |
4440 | return ERR_PTR(err); |
4441 | |
4442 | bp->destroy = bp_perf_event_destroy; |
4443 | |
4444 | return &perf_ops_bp; |
4445 | } |
4446 | |
4447 | void perf_bp_event(struct perf_event *bp, void *data) |
4448 | { |
4449 | struct perf_sample_data sample; |
4450 | struct pt_regs *regs = data; |
4451 | |
4452 | perf_sample_data_init(&sample, bp->attr.bp_addr); |
4453 | |
4454 | if (!perf_exclude_event(bp, regs)) |
4455 | perf_swevent_add(bp, 1, 1, &sample, regs); |
4456 | } |
4457 | #else |
4458 | static const struct pmu *bp_perf_event_init(struct perf_event *bp) |
4459 | { |
4460 | return NULL; |
4461 | } |
4462 | |
4463 | void perf_bp_event(struct perf_event *bp, void *regs) |
4464 | { |
4465 | } |
4466 | #endif |
4467 | |
4468 | atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX]; |
4469 | |
4470 | static void sw_perf_event_destroy(struct perf_event *event) |
4471 | { |
4472 | u64 event_id = event->attr.config; |
4473 | |
4474 | WARN_ON(event->parent); |
4475 | |
4476 | atomic_dec(&perf_swevent_enabled[event_id]); |
4477 | } |
4478 | |
4479 | static const struct pmu *sw_perf_event_init(struct perf_event *event) |
4480 | { |
4481 | const struct pmu *pmu = NULL; |
4482 | u64 event_id = event->attr.config; |
4483 | |
4484 | /* |
4485 | * Software events (currently) can't in general distinguish |
4486 | * between user, kernel and hypervisor events. |
4487 | * However, context switches and cpu migrations are considered |
4488 | * to be kernel events, and page faults are never hypervisor |
4489 | * events. |
4490 | */ |
4491 | switch (event_id) { |
4492 | case PERF_COUNT_SW_CPU_CLOCK: |
4493 | pmu = &perf_ops_cpu_clock; |
4494 | |
4495 | break; |
4496 | case PERF_COUNT_SW_TASK_CLOCK: |
4497 | /* |
4498 | * If the user instantiates this as a per-cpu event, |
4499 | * use the cpu_clock event instead. |
4500 | */ |
4501 | if (event->ctx->task) |
4502 | pmu = &perf_ops_task_clock; |
4503 | else |
4504 | pmu = &perf_ops_cpu_clock; |
4505 | |
4506 | break; |
4507 | case PERF_COUNT_SW_PAGE_FAULTS: |
4508 | case PERF_COUNT_SW_PAGE_FAULTS_MIN: |
4509 | case PERF_COUNT_SW_PAGE_FAULTS_MAJ: |
4510 | case PERF_COUNT_SW_CONTEXT_SWITCHES: |
4511 | case PERF_COUNT_SW_CPU_MIGRATIONS: |
4512 | case PERF_COUNT_SW_ALIGNMENT_FAULTS: |
4513 | case PERF_COUNT_SW_EMULATION_FAULTS: |
4514 | if (!event->parent) { |
4515 | atomic_inc(&perf_swevent_enabled[event_id]); |
4516 | event->destroy = sw_perf_event_destroy; |
4517 | } |
4518 | pmu = &perf_ops_generic; |
4519 | break; |
4520 | } |
4521 | |
4522 | return pmu; |
4523 | } |
4524 | |
4525 | /* |
4526 | * Allocate and initialize a event structure |
4527 | */ |
4528 | static struct perf_event * |
4529 | perf_event_alloc(struct perf_event_attr *attr, |
4530 | int cpu, |
4531 | struct perf_event_context *ctx, |
4532 | struct perf_event *group_leader, |
4533 | struct perf_event *parent_event, |
4534 | perf_overflow_handler_t overflow_handler, |
4535 | gfp_t gfpflags) |
4536 | { |
4537 | const struct pmu *pmu; |
4538 | struct perf_event *event; |
4539 | struct hw_perf_event *hwc; |
4540 | long err; |
4541 | |
4542 | event = kzalloc(sizeof(*event), gfpflags); |
4543 | if (!event) |
4544 | return ERR_PTR(-ENOMEM); |
4545 | |
4546 | /* |
4547 | * Single events are their own group leaders, with an |
4548 | * empty sibling list: |
4549 | */ |
4550 | if (!group_leader) |
4551 | group_leader = event; |
4552 | |
4553 | mutex_init(&event->child_mutex); |
4554 | INIT_LIST_HEAD(&event->child_list); |
4555 | |
4556 | INIT_LIST_HEAD(&event->group_entry); |
4557 | INIT_LIST_HEAD(&event->event_entry); |
4558 | INIT_LIST_HEAD(&event->sibling_list); |
4559 | init_waitqueue_head(&event->waitq); |
4560 | |
4561 | mutex_init(&event->mmap_mutex); |
4562 | |
4563 | event->cpu = cpu; |
4564 | event->attr = *attr; |
4565 | event->group_leader = group_leader; |
4566 | event->pmu = NULL; |
4567 | event->ctx = ctx; |
4568 | event->oncpu = -1; |
4569 | |
4570 | event->parent = parent_event; |
4571 | |
4572 | event->ns = get_pid_ns(current->nsproxy->pid_ns); |
4573 | event->id = atomic64_inc_return(&perf_event_id); |
4574 | |
4575 | event->state = PERF_EVENT_STATE_INACTIVE; |
4576 | |
4577 | if (!overflow_handler && parent_event) |
4578 | overflow_handler = parent_event->overflow_handler; |
4579 | |
4580 | event->overflow_handler = overflow_handler; |
4581 | |
4582 | if (attr->disabled) |
4583 | event->state = PERF_EVENT_STATE_OFF; |
4584 | |
4585 | pmu = NULL; |
4586 | |
4587 | hwc = &event->hw; |
4588 | hwc->sample_period = attr->sample_period; |
4589 | if (attr->freq && attr->sample_freq) |
4590 | hwc->sample_period = 1; |
4591 | hwc->last_period = hwc->sample_period; |
4592 | |
4593 | atomic64_set(&hwc->period_left, hwc->sample_period); |
4594 | |
4595 | /* |
4596 | * we currently do not support PERF_FORMAT_GROUP on inherited events |
4597 | */ |
4598 | if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) |
4599 | goto done; |
4600 | |
4601 | switch (attr->type) { |
4602 | case PERF_TYPE_RAW: |
4603 | case PERF_TYPE_HARDWARE: |
4604 | case PERF_TYPE_HW_CACHE: |
4605 | pmu = hw_perf_event_init(event); |
4606 | break; |
4607 | |
4608 | case PERF_TYPE_SOFTWARE: |
4609 | pmu = sw_perf_event_init(event); |
4610 | break; |
4611 | |
4612 | case PERF_TYPE_TRACEPOINT: |
4613 | pmu = tp_perf_event_init(event); |
4614 | break; |
4615 | |
4616 | case PERF_TYPE_BREAKPOINT: |
4617 | pmu = bp_perf_event_init(event); |
4618 | break; |
4619 | |
4620 | |
4621 | default: |
4622 | break; |
4623 | } |
4624 | done: |
4625 | err = 0; |
4626 | if (!pmu) |
4627 | err = -EINVAL; |
4628 | else if (IS_ERR(pmu)) |
4629 | err = PTR_ERR(pmu); |
4630 | |
4631 | if (err) { |
4632 | if (event->ns) |
4633 | put_pid_ns(event->ns); |
4634 | kfree(event); |
4635 | return ERR_PTR(err); |
4636 | } |
4637 | |
4638 | event->pmu = pmu; |
4639 | |
4640 | if (!event->parent) { |
4641 | atomic_inc(&nr_events); |
4642 | if (event->attr.mmap) |
4643 | atomic_inc(&nr_mmap_events); |
4644 | if (event->attr.comm) |
4645 | atomic_inc(&nr_comm_events); |
4646 | if (event->attr.task) |
4647 | atomic_inc(&nr_task_events); |
4648 | } |
4649 | |
4650 | return event; |
4651 | } |
4652 | |
4653 | static int perf_copy_attr(struct perf_event_attr __user *uattr, |
4654 | struct perf_event_attr *attr) |
4655 | { |
4656 | u32 size; |
4657 | int ret; |
4658 | |
4659 | if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) |
4660 | return -EFAULT; |
4661 | |
4662 | /* |
4663 | * zero the full structure, so that a short copy will be nice. |
4664 | */ |
4665 | memset(attr, 0, sizeof(*attr)); |
4666 | |
4667 | ret = get_user(size, &uattr->size); |
4668 | if (ret) |
4669 | return ret; |
4670 | |
4671 | if (size > PAGE_SIZE) /* silly large */ |
4672 | goto err_size; |
4673 | |
4674 | if (!size) /* abi compat */ |
4675 | size = PERF_ATTR_SIZE_VER0; |
4676 | |
4677 | if (size < PERF_ATTR_SIZE_VER0) |
4678 | goto err_size; |
4679 | |
4680 | /* |
4681 | * If we're handed a bigger struct than we know of, |
4682 | * ensure all the unknown bits are 0 - i.e. new |
4683 | * user-space does not rely on any kernel feature |
4684 | * extensions we dont know about yet. |
4685 | */ |
4686 | if (size > sizeof(*attr)) { |
4687 | unsigned char __user *addr; |
4688 | unsigned char __user *end; |
4689 | unsigned char val; |
4690 | |
4691 | addr = (void __user *)uattr + sizeof(*attr); |
4692 | end = (void __user *)uattr + size; |
4693 | |
4694 | for (; addr < end; addr++) { |
4695 | ret = get_user(val, addr); |
4696 | if (ret) |
4697 | return ret; |
4698 | if (val) |
4699 | goto err_size; |
4700 | } |
4701 | size = sizeof(*attr); |
4702 | } |
4703 | |
4704 | ret = copy_from_user(attr, uattr, size); |
4705 | if (ret) |
4706 | return -EFAULT; |
4707 | |
4708 | /* |
4709 | * If the type exists, the corresponding creation will verify |
4710 | * the attr->config. |
4711 | */ |
4712 | if (attr->type >= PERF_TYPE_MAX) |
4713 | return -EINVAL; |
4714 | |
4715 | if (attr->__reserved_1) |
4716 | return -EINVAL; |
4717 | |
4718 | if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) |
4719 | return -EINVAL; |
4720 | |
4721 | if (attr->read_format & ~(PERF_FORMAT_MAX-1)) |
4722 | return -EINVAL; |
4723 | |
4724 | out: |
4725 | return ret; |
4726 | |
4727 | err_size: |
4728 | put_user(sizeof(*attr), &uattr->size); |
4729 | ret = -E2BIG; |
4730 | goto out; |
4731 | } |
4732 | |
4733 | static int perf_event_set_output(struct perf_event *event, int output_fd) |
4734 | { |
4735 | struct perf_event *output_event = NULL; |
4736 | struct file *output_file = NULL; |
4737 | struct perf_event *old_output; |
4738 | int fput_needed = 0; |
4739 | int ret = -EINVAL; |
4740 | |
4741 | if (!output_fd) |
4742 | goto set; |
4743 | |
4744 | output_file = fget_light(output_fd, &fput_needed); |
4745 | if (!output_file) |
4746 | return -EBADF; |
4747 | |
4748 | if (output_file->f_op != &perf_fops) |
4749 | goto out; |
4750 | |
4751 | output_event = output_file->private_data; |
4752 | |
4753 | /* Don't chain output fds */ |
4754 | if (output_event->output) |
4755 | goto out; |
4756 | |
4757 | /* Don't set an output fd when we already have an output channel */ |
4758 | if (event->data) |
4759 | goto out; |
4760 | |
4761 | atomic_long_inc(&output_file->f_count); |
4762 | |
4763 | set: |
4764 | mutex_lock(&event->mmap_mutex); |
4765 | old_output = event->output; |
4766 | rcu_assign_pointer(event->output, output_event); |
4767 | mutex_unlock(&event->mmap_mutex); |
4768 | |
4769 | if (old_output) { |
4770 | /* |
4771 | * we need to make sure no existing perf_output_*() |
4772 | * is still referencing this event. |
4773 | */ |
4774 | synchronize_rcu(); |
4775 | fput(old_output->filp); |
4776 | } |
4777 | |
4778 | ret = 0; |
4779 | out: |
4780 | fput_light(output_file, fput_needed); |
4781 | return ret; |
4782 | } |
4783 | |
4784 | /** |
4785 | * sys_perf_event_open - open a performance event, associate it to a task/cpu |
4786 | * |
4787 | * @attr_uptr: event_id type attributes for monitoring/sampling |
4788 | * @pid: target pid |
4789 | * @cpu: target cpu |
4790 | * @group_fd: group leader event fd |
4791 | */ |
4792 | SYSCALL_DEFINE5(perf_event_open, |
4793 | struct perf_event_attr __user *, attr_uptr, |
4794 | pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) |
4795 | { |
4796 | struct perf_event *event, *group_leader; |
4797 | struct perf_event_attr attr; |
4798 | struct perf_event_context *ctx; |
4799 | struct file *event_file = NULL; |
4800 | struct file *group_file = NULL; |
4801 | int fput_needed = 0; |
4802 | int fput_needed2 = 0; |
4803 | int err; |
4804 | |
4805 | /* for future expandability... */ |
4806 | if (flags & ~(PERF_FLAG_FD_NO_GROUP | PERF_FLAG_FD_OUTPUT)) |
4807 | return -EINVAL; |
4808 | |
4809 | err = perf_copy_attr(attr_uptr, &attr); |
4810 | if (err) |
4811 | return err; |
4812 | |
4813 | if (!attr.exclude_kernel) { |
4814 | if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) |
4815 | return -EACCES; |
4816 | } |
4817 | |
4818 | if (attr.freq) { |
4819 | if (attr.sample_freq > sysctl_perf_event_sample_rate) |
4820 | return -EINVAL; |
4821 | } |
4822 | |
4823 | /* |
4824 | * Get the target context (task or percpu): |
4825 | */ |
4826 | ctx = find_get_context(pid, cpu); |
4827 | if (IS_ERR(ctx)) |
4828 | return PTR_ERR(ctx); |
4829 | |
4830 | /* |
4831 | * Look up the group leader (we will attach this event to it): |
4832 | */ |
4833 | group_leader = NULL; |
4834 | if (group_fd != -1 && !(flags & PERF_FLAG_FD_NO_GROUP)) { |
4835 | err = -EINVAL; |
4836 | group_file = fget_light(group_fd, &fput_needed); |
4837 | if (!group_file) |
4838 | goto err_put_context; |
4839 | if (group_file->f_op != &perf_fops) |
4840 | goto err_put_context; |
4841 | |
4842 | group_leader = group_file->private_data; |
4843 | /* |
4844 | * Do not allow a recursive hierarchy (this new sibling |
4845 | * becoming part of another group-sibling): |
4846 | */ |
4847 | if (group_leader->group_leader != group_leader) |
4848 | goto err_put_context; |
4849 | /* |
4850 | * Do not allow to attach to a group in a different |
4851 | * task or CPU context: |
4852 | */ |
4853 | if (group_leader->ctx != ctx) |
4854 | goto err_put_context; |
4855 | /* |
4856 | * Only a group leader can be exclusive or pinned |
4857 | */ |
4858 | if (attr.exclusive || attr.pinned) |
4859 | goto err_put_context; |
4860 | } |
4861 | |
4862 | event = perf_event_alloc(&attr, cpu, ctx, group_leader, |
4863 | NULL, NULL, GFP_KERNEL); |
4864 | err = PTR_ERR(event); |
4865 | if (IS_ERR(event)) |
4866 | goto err_put_context; |
4867 | |
4868 | err = anon_inode_getfd("[perf_event]", &perf_fops, event, O_RDWR); |
4869 | if (err < 0) |
4870 | goto err_free_put_context; |
4871 | |
4872 | event_file = fget_light(err, &fput_needed2); |
4873 | if (!event_file) |
4874 | goto err_free_put_context; |
4875 | |
4876 | if (flags & PERF_FLAG_FD_OUTPUT) { |
4877 | err = perf_event_set_output(event, group_fd); |
4878 | if (err) |
4879 | goto err_fput_free_put_context; |
4880 | } |
4881 | |
4882 | event->filp = event_file; |
4883 | WARN_ON_ONCE(ctx->parent_ctx); |
4884 | mutex_lock(&ctx->mutex); |
4885 | perf_install_in_context(ctx, event, cpu); |
4886 | ++ctx->generation; |
4887 | mutex_unlock(&ctx->mutex); |
4888 | |
4889 | event->owner = current; |
4890 | get_task_struct(current); |
4891 | mutex_lock(¤t->perf_event_mutex); |
4892 | list_add_tail(&event->owner_entry, ¤t->perf_event_list); |
4893 | mutex_unlock(¤t->perf_event_mutex); |
4894 | |
4895 | err_fput_free_put_context: |
4896 | fput_light(event_file, fput_needed2); |
4897 | |
4898 | err_free_put_context: |
4899 | if (err < 0) |
4900 | kfree(event); |
4901 | |
4902 | err_put_context: |
4903 | if (err < 0) |
4904 | put_ctx(ctx); |
4905 | |
4906 | fput_light(group_file, fput_needed); |
4907 | |
4908 | return err; |
4909 | } |
4910 | |
4911 | /** |
4912 | * perf_event_create_kernel_counter |
4913 | * |
4914 | * @attr: attributes of the counter to create |
4915 | * @cpu: cpu in which the counter is bound |
4916 | * @pid: task to profile |
4917 | */ |
4918 | struct perf_event * |
4919 | perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, |
4920 | pid_t pid, |
4921 | perf_overflow_handler_t overflow_handler) |
4922 | { |
4923 | struct perf_event *event; |
4924 | struct perf_event_context *ctx; |
4925 | int err; |
4926 | |
4927 | /* |
4928 | * Get the target context (task or percpu): |
4929 | */ |
4930 | |
4931 | ctx = find_get_context(pid, cpu); |
4932 | if (IS_ERR(ctx)) { |
4933 | err = PTR_ERR(ctx); |
4934 | goto err_exit; |
4935 | } |
4936 | |
4937 | event = perf_event_alloc(attr, cpu, ctx, NULL, |
4938 | NULL, overflow_handler, GFP_KERNEL); |
4939 | if (IS_ERR(event)) { |
4940 | err = PTR_ERR(event); |
4941 | goto err_put_context; |
4942 | } |
4943 | |
4944 | event->filp = NULL; |
4945 | WARN_ON_ONCE(ctx->parent_ctx); |
4946 | mutex_lock(&ctx->mutex); |
4947 | perf_install_in_context(ctx, event, cpu); |
4948 | ++ctx->generation; |
4949 | mutex_unlock(&ctx->mutex); |
4950 | |
4951 | event->owner = current; |
4952 | get_task_struct(current); |
4953 | mutex_lock(¤t->perf_event_mutex); |
4954 | list_add_tail(&event->owner_entry, ¤t->perf_event_list); |
4955 | mutex_unlock(¤t->perf_event_mutex); |
4956 | |
4957 | return event; |
4958 | |
4959 | err_put_context: |
4960 | put_ctx(ctx); |
4961 | err_exit: |
4962 | return ERR_PTR(err); |
4963 | } |
4964 | EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); |
4965 | |
4966 | /* |
4967 | * inherit a event from parent task to child task: |
4968 | */ |
4969 | static struct perf_event * |
4970 | inherit_event(struct perf_event *parent_event, |
4971 | struct task_struct *parent, |
4972 | struct perf_event_context *parent_ctx, |
4973 | struct task_struct *child, |
4974 | struct perf_event *group_leader, |
4975 | struct perf_event_context *child_ctx) |
4976 | { |
4977 | struct perf_event *child_event; |
4978 | |
4979 | /* |
4980 | * Instead of creating recursive hierarchies of events, |
4981 | * we link inherited events back to the original parent, |
4982 | * which has a filp for sure, which we use as the reference |
4983 | * count: |
4984 | */ |
4985 | if (parent_event->parent) |
4986 | parent_event = parent_event->parent; |
4987 | |
4988 | child_event = perf_event_alloc(&parent_event->attr, |
4989 | parent_event->cpu, child_ctx, |
4990 | group_leader, parent_event, |
4991 | NULL, GFP_KERNEL); |
4992 | if (IS_ERR(child_event)) |
4993 | return child_event; |
4994 | get_ctx(child_ctx); |
4995 | |
4996 | /* |
4997 | * Make the child state follow the state of the parent event, |
4998 | * not its attr.disabled bit. We hold the parent's mutex, |
4999 | * so we won't race with perf_event_{en, dis}able_family. |
5000 | */ |
5001 | if (parent_event->state >= PERF_EVENT_STATE_INACTIVE) |
5002 | child_event->state = PERF_EVENT_STATE_INACTIVE; |
5003 | else |
5004 | child_event->state = PERF_EVENT_STATE_OFF; |
5005 | |
5006 | if (parent_event->attr.freq) { |
5007 | u64 sample_period = parent_event->hw.sample_period; |
5008 | struct hw_perf_event *hwc = &child_event->hw; |
5009 | |
5010 | hwc->sample_period = sample_period; |
5011 | hwc->last_period = sample_period; |
5012 | |
5013 | atomic64_set(&hwc->period_left, sample_period); |
5014 | } |
5015 | |
5016 | child_event->overflow_handler = parent_event->overflow_handler; |
5017 | |
5018 | /* |
5019 | * Link it up in the child's context: |
5020 | */ |
5021 | add_event_to_ctx(child_event, child_ctx); |
5022 | |
5023 | /* |
5024 | * Get a reference to the parent filp - we will fput it |
5025 | * when the child event exits. This is safe to do because |
5026 | * we are in the parent and we know that the filp still |
5027 | * exists and has a nonzero count: |
5028 | */ |
5029 | atomic_long_inc(&parent_event->filp->f_count); |
5030 | |
5031 | /* |
5032 | * Link this into the parent event's child list |
5033 | */ |
5034 | WARN_ON_ONCE(parent_event->ctx->parent_ctx); |
5035 | mutex_lock(&parent_event->child_mutex); |
5036 | list_add_tail(&child_event->child_list, &parent_event->child_list); |
5037 | mutex_unlock(&parent_event->child_mutex); |
5038 | |
5039 | return child_event; |
5040 | } |
5041 | |
5042 | static int inherit_group(struct perf_event *parent_event, |
5043 | struct task_struct *parent, |
5044 | struct perf_event_context *parent_ctx, |
5045 | struct task_struct *child, |
5046 | struct perf_event_context *child_ctx) |
5047 | { |
5048 | struct perf_event *leader; |
5049 | struct perf_event *sub; |
5050 | struct perf_event *child_ctr; |
5051 | |
5052 | leader = inherit_event(parent_event, parent, parent_ctx, |
5053 | child, NULL, child_ctx); |
5054 | if (IS_ERR(leader)) |
5055 | return PTR_ERR(leader); |
5056 | list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { |
5057 | child_ctr = inherit_event(sub, parent, parent_ctx, |
5058 | child, leader, child_ctx); |
5059 | if (IS_ERR(child_ctr)) |
5060 | return PTR_ERR(child_ctr); |
5061 | } |
5062 | return 0; |
5063 | } |
5064 | |
5065 | static void sync_child_event(struct perf_event *child_event, |
5066 | struct task_struct *child) |
5067 | { |
5068 | struct perf_event *parent_event = child_event->parent; |
5069 | u64 child_val; |
5070 | |
5071 | if (child_event->attr.inherit_stat) |
5072 | perf_event_read_event(child_event, child); |
5073 | |
5074 | child_val = atomic64_read(&child_event->count); |
5075 | |
5076 | /* |
5077 | * Add back the child's count to the parent's count: |
5078 | */ |
5079 | atomic64_add(child_val, &parent_event->count); |
5080 | atomic64_add(child_event->total_time_enabled, |
5081 | &parent_event->child_total_time_enabled); |
5082 | atomic64_add(child_event->total_time_running, |
5083 | &parent_event->child_total_time_running); |
5084 | |
5085 | /* |
5086 | * Remove this event from the parent's list |
5087 | */ |
5088 | WARN_ON_ONCE(parent_event->ctx->parent_ctx); |
5089 | mutex_lock(&parent_event->child_mutex); |
5090 | list_del_init(&child_event->child_list); |
5091 | mutex_unlock(&parent_event->child_mutex); |
5092 | |
5093 | /* |
5094 | * Release the parent event, if this was the last |
5095 | * reference to it. |
5096 | */ |
5097 | fput(parent_event->filp); |
5098 | } |
5099 | |
5100 | static void |
5101 | __perf_event_exit_task(struct perf_event *child_event, |
5102 | struct perf_event_context *child_ctx, |
5103 | struct task_struct *child) |
5104 | { |
5105 | struct perf_event *parent_event; |
5106 | |
5107 | perf_event_remove_from_context(child_event); |
5108 | |
5109 | parent_event = child_event->parent; |
5110 | /* |
5111 | * It can happen that parent exits first, and has events |
5112 | * that are still around due to the child reference. These |
5113 | * events need to be zapped - but otherwise linger. |
5114 | */ |
5115 | if (parent_event) { |
5116 | sync_child_event(child_event, child); |
5117 | free_event(child_event); |
5118 | } |
5119 | } |
5120 | |
5121 | /* |
5122 | * When a child task exits, feed back event values to parent events. |
5123 | */ |
5124 | void perf_event_exit_task(struct task_struct *child) |
5125 | { |
5126 | struct perf_event *child_event, *tmp; |
5127 | struct perf_event_context *child_ctx; |
5128 | unsigned long flags; |
5129 | |
5130 | if (likely(!child->perf_event_ctxp)) { |
5131 | perf_event_task(child, NULL, 0); |
5132 | return; |
5133 | } |
5134 | |
5135 | local_irq_save(flags); |
5136 | /* |
5137 | * We can't reschedule here because interrupts are disabled, |
5138 | * and either child is current or it is a task that can't be |
5139 | * scheduled, so we are now safe from rescheduling changing |
5140 | * our context. |
5141 | */ |
5142 | child_ctx = child->perf_event_ctxp; |
5143 | __perf_event_task_sched_out(child_ctx); |
5144 | |
5145 | /* |
5146 | * Take the context lock here so that if find_get_context is |
5147 | * reading child->perf_event_ctxp, we wait until it has |
5148 | * incremented the context's refcount before we do put_ctx below. |
5149 | */ |
5150 | raw_spin_lock(&child_ctx->lock); |
5151 | child->perf_event_ctxp = NULL; |
5152 | /* |
5153 | * If this context is a clone; unclone it so it can't get |
5154 | * swapped to another process while we're removing all |
5155 | * the events from it. |
5156 | */ |
5157 | unclone_ctx(child_ctx); |
5158 | update_context_time(child_ctx); |
5159 | raw_spin_unlock_irqrestore(&child_ctx->lock, flags); |
5160 | |
5161 | /* |
5162 | * Report the task dead after unscheduling the events so that we |
5163 | * won't get any samples after PERF_RECORD_EXIT. We can however still |
5164 | * get a few PERF_RECORD_READ events. |
5165 | */ |
5166 | perf_event_task(child, child_ctx, 0); |
5167 | |
5168 | /* |
5169 | * We can recurse on the same lock type through: |
5170 | * |
5171 | * __perf_event_exit_task() |
5172 | * sync_child_event() |
5173 | * fput(parent_event->filp) |
5174 | * perf_release() |
5175 | * mutex_lock(&ctx->mutex) |
5176 | * |
5177 | * But since its the parent context it won't be the same instance. |
5178 | */ |
5179 | mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING); |
5180 | |
5181 | again: |
5182 | list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups, |
5183 | group_entry) |
5184 | __perf_event_exit_task(child_event, child_ctx, child); |
5185 | |
5186 | list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups, |
5187 | group_entry) |
5188 | __perf_event_exit_task(child_event, child_ctx, child); |
5189 | |
5190 | /* |
5191 | * If the last event was a group event, it will have appended all |
5192 | * its siblings to the list, but we obtained 'tmp' before that which |
5193 | * will still point to the list head terminating the iteration. |
5194 | */ |
5195 | if (!list_empty(&child_ctx->pinned_groups) || |
5196 | !list_empty(&child_ctx->flexible_groups)) |
5197 | goto again; |
5198 | |
5199 | mutex_unlock(&child_ctx->mutex); |
5200 | |
5201 | put_ctx(child_ctx); |
5202 | } |
5203 | |
5204 | static void perf_free_event(struct perf_event *event, |
5205 | struct perf_event_context *ctx) |
5206 | { |
5207 | struct perf_event *parent = event->parent; |
5208 | |
5209 | if (WARN_ON_ONCE(!parent)) |
5210 | return; |
5211 | |
5212 | mutex_lock(&parent->child_mutex); |
5213 | list_del_init(&event->child_list); |
5214 | mutex_unlock(&parent->child_mutex); |
5215 | |
5216 | fput(parent->filp); |
5217 | |
5218 | list_del_event(event, ctx); |
5219 | free_event(event); |
5220 | } |
5221 | |
5222 | /* |
5223 | * free an unexposed, unused context as created by inheritance by |
5224 | * init_task below, used by fork() in case of fail. |
5225 | */ |
5226 | void perf_event_free_task(struct task_struct *task) |
5227 | { |
5228 | struct perf_event_context *ctx = task->perf_event_ctxp; |
5229 | struct perf_event *event, *tmp; |
5230 | |
5231 | if (!ctx) |
5232 | return; |
5233 | |
5234 | mutex_lock(&ctx->mutex); |
5235 | again: |
5236 | list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) |
5237 | perf_free_event(event, ctx); |
5238 | |
5239 | list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, |
5240 | group_entry) |
5241 | perf_free_event(event, ctx); |
5242 | |
5243 | if (!list_empty(&ctx->pinned_groups) || |
5244 | !list_empty(&ctx->flexible_groups)) |
5245 | goto again; |
5246 | |
5247 | mutex_unlock(&ctx->mutex); |
5248 | |
5249 | put_ctx(ctx); |
5250 | } |
5251 | |
5252 | static int |
5253 | inherit_task_group(struct perf_event *event, struct task_struct *parent, |
5254 | struct perf_event_context *parent_ctx, |
5255 | struct task_struct *child, |
5256 | int *inherited_all) |
5257 | { |
5258 | int ret; |
5259 | struct perf_event_context *child_ctx = child->perf_event_ctxp; |
5260 | |
5261 | if (!event->attr.inherit) { |
5262 | *inherited_all = 0; |
5263 | return 0; |
5264 | } |
5265 | |
5266 | if (!child_ctx) { |
5267 | /* |
5268 | * This is executed from the parent task context, so |
5269 | * inherit events that have been marked for cloning. |
5270 | * First allocate and initialize a context for the |
5271 | * child. |
5272 | */ |
5273 | |
5274 | child_ctx = kzalloc(sizeof(struct perf_event_context), |
5275 | GFP_KERNEL); |
5276 | if (!child_ctx) |
5277 | return -ENOMEM; |
5278 | |
5279 | __perf_event_init_context(child_ctx, child); |
5280 | child->perf_event_ctxp = child_ctx; |
5281 | get_task_struct(child); |
5282 | } |
5283 | |
5284 | ret = inherit_group(event, parent, parent_ctx, |
5285 | child, child_ctx); |
5286 | |
5287 | if (ret) |
5288 | *inherited_all = 0; |
5289 | |
5290 | return ret; |
5291 | } |
5292 | |
5293 | |
5294 | /* |
5295 | * Initialize the perf_event context in task_struct |
5296 | */ |
5297 | int perf_event_init_task(struct task_struct *child) |
5298 | { |
5299 | struct perf_event_context *child_ctx, *parent_ctx; |
5300 | struct perf_event_context *cloned_ctx; |
5301 | struct perf_event *event; |
5302 | struct task_struct *parent = current; |
5303 | int inherited_all = 1; |
5304 | int ret = 0; |
5305 | |
5306 | child->perf_event_ctxp = NULL; |
5307 | |
5308 | mutex_init(&child->perf_event_mutex); |
5309 | INIT_LIST_HEAD(&child->perf_event_list); |
5310 | |
5311 | if (likely(!parent->perf_event_ctxp)) |
5312 | return 0; |
5313 | |
5314 | /* |
5315 | * If the parent's context is a clone, pin it so it won't get |
5316 | * swapped under us. |
5317 | */ |
5318 | parent_ctx = perf_pin_task_context(parent); |
5319 | |
5320 | /* |
5321 | * No need to check if parent_ctx != NULL here; since we saw |
5322 | * it non-NULL earlier, the only reason for it to become NULL |
5323 | * is if we exit, and since we're currently in the middle of |
5324 | * a fork we can't be exiting at the same time. |
5325 | */ |
5326 | |
5327 | /* |
5328 | * Lock the parent list. No need to lock the child - not PID |
5329 | * hashed yet and not running, so nobody can access it. |
5330 | */ |
5331 | mutex_lock(&parent_ctx->mutex); |
5332 | |
5333 | /* |
5334 | * We dont have to disable NMIs - we are only looking at |
5335 | * the list, not manipulating it: |
5336 | */ |
5337 | list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { |
5338 | ret = inherit_task_group(event, parent, parent_ctx, child, |
5339 | &inherited_all); |
5340 | if (ret) |
5341 | break; |
5342 | } |
5343 | |
5344 | list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { |
5345 | ret = inherit_task_group(event, parent, parent_ctx, child, |
5346 | &inherited_all); |
5347 | if (ret) |
5348 | break; |
5349 | } |
5350 | |
5351 | child_ctx = child->perf_event_ctxp; |
5352 | |
5353 | if (child_ctx && inherited_all) { |
5354 | /* |
5355 | * Mark the child context as a clone of the parent |
5356 | * context, or of whatever the parent is a clone of. |
5357 | * Note that if the parent is a clone, it could get |
5358 | * uncloned at any point, but that doesn't matter |
5359 | * because the list of events and the generation |
5360 | * count can't have changed since we took the mutex. |
5361 | */ |
5362 | cloned_ctx = rcu_dereference(parent_ctx->parent_ctx); |
5363 | if (cloned_ctx) { |
5364 | child_ctx->parent_ctx = cloned_ctx; |
5365 | child_ctx->parent_gen = parent_ctx->parent_gen; |
5366 | } else { |
5367 | child_ctx->parent_ctx = parent_ctx; |
5368 | child_ctx->parent_gen = parent_ctx->generation; |
5369 | } |
5370 | get_ctx(child_ctx->parent_ctx); |
5371 | } |
5372 | |
5373 | mutex_unlock(&parent_ctx->mutex); |
5374 | |
5375 | perf_unpin_context(parent_ctx); |
5376 | |
5377 | return ret; |
5378 | } |
5379 | |
5380 | static void __init perf_event_init_all_cpus(void) |
5381 | { |
5382 | int cpu; |
5383 | struct perf_cpu_context *cpuctx; |
5384 | |
5385 | for_each_possible_cpu(cpu) { |
5386 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
5387 | __perf_event_init_context(&cpuctx->ctx, NULL); |
5388 | } |
5389 | } |
5390 | |
5391 | static void __cpuinit perf_event_init_cpu(int cpu) |
5392 | { |
5393 | struct perf_cpu_context *cpuctx; |
5394 | |
5395 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
5396 | |
5397 | spin_lock(&perf_resource_lock); |
5398 | cpuctx->max_pertask = perf_max_events - perf_reserved_percpu; |
5399 | spin_unlock(&perf_resource_lock); |
5400 | } |
5401 | |
5402 | #ifdef CONFIG_HOTPLUG_CPU |
5403 | static void __perf_event_exit_cpu(void *info) |
5404 | { |
5405 | struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); |
5406 | struct perf_event_context *ctx = &cpuctx->ctx; |
5407 | struct perf_event *event, *tmp; |
5408 | |
5409 | list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) |
5410 | __perf_event_remove_from_context(event); |
5411 | list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) |
5412 | __perf_event_remove_from_context(event); |
5413 | } |
5414 | static void perf_event_exit_cpu(int cpu) |
5415 | { |
5416 | struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); |
5417 | struct perf_event_context *ctx = &cpuctx->ctx; |
5418 | |
5419 | mutex_lock(&ctx->mutex); |
5420 | smp_call_function_single(cpu, __perf_event_exit_cpu, NULL, 1); |
5421 | mutex_unlock(&ctx->mutex); |
5422 | } |
5423 | #else |
5424 | static inline void perf_event_exit_cpu(int cpu) { } |
5425 | #endif |
5426 | |
5427 | static int __cpuinit |
5428 | perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) |
5429 | { |
5430 | unsigned int cpu = (long)hcpu; |
5431 | |
5432 | switch (action) { |
5433 | |
5434 | case CPU_UP_PREPARE: |
5435 | case CPU_UP_PREPARE_FROZEN: |
5436 | perf_event_init_cpu(cpu); |
5437 | break; |
5438 | |
5439 | case CPU_DOWN_PREPARE: |
5440 | case CPU_DOWN_PREPARE_FROZEN: |
5441 | perf_event_exit_cpu(cpu); |
5442 | break; |
5443 | |
5444 | default: |
5445 | break; |
5446 | } |
5447 | |
5448 | return NOTIFY_OK; |
5449 | } |
5450 | |
5451 | /* |
5452 | * This has to have a higher priority than migration_notifier in sched.c. |
5453 | */ |
5454 | static struct notifier_block __cpuinitdata perf_cpu_nb = { |
5455 | .notifier_call = perf_cpu_notify, |
5456 | .priority = 20, |
5457 | }; |
5458 | |
5459 | void __init perf_event_init(void) |
5460 | { |
5461 | perf_event_init_all_cpus(); |
5462 | perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE, |
5463 | (void *)(long)smp_processor_id()); |
5464 | perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE, |
5465 | (void *)(long)smp_processor_id()); |
5466 | register_cpu_notifier(&perf_cpu_nb); |
5467 | } |
5468 | |
5469 | static ssize_t perf_show_reserve_percpu(struct sysdev_class *class, |
5470 | struct sysdev_class_attribute *attr, |
5471 | char *buf) |
5472 | { |
5473 | return sprintf(buf, "%d\n", perf_reserved_percpu); |
5474 | } |
5475 | |
5476 | static ssize_t |
5477 | perf_set_reserve_percpu(struct sysdev_class *class, |
5478 | struct sysdev_class_attribute *attr, |
5479 | const char *buf, |
5480 | size_t count) |
5481 | { |
5482 | struct perf_cpu_context *cpuctx; |
5483 | unsigned long val; |
5484 | int err, cpu, mpt; |
5485 | |
5486 | err = strict_strtoul(buf, 10, &val); |
5487 | if (err) |
5488 | return err; |
5489 | if (val > perf_max_events) |
5490 | return -EINVAL; |
5491 | |
5492 | spin_lock(&perf_resource_lock); |
5493 | perf_reserved_percpu = val; |
5494 | for_each_online_cpu(cpu) { |
5495 | cpuctx = &per_cpu(perf_cpu_context, cpu); |
5496 | raw_spin_lock_irq(&cpuctx->ctx.lock); |
5497 | mpt = min(perf_max_events - cpuctx->ctx.nr_events, |
5498 | perf_max_events - perf_reserved_percpu); |
5499 | cpuctx->max_pertask = mpt; |
5500 | raw_spin_unlock_irq(&cpuctx->ctx.lock); |
5501 | } |
5502 | spin_unlock(&perf_resource_lock); |
5503 | |
5504 | return count; |
5505 | } |
5506 | |
5507 | static ssize_t perf_show_overcommit(struct sysdev_class *class, |
5508 | struct sysdev_class_attribute *attr, |
5509 | char *buf) |
5510 | { |
5511 | return sprintf(buf, "%d\n", perf_overcommit); |
5512 | } |
5513 | |
5514 | static ssize_t |
5515 | perf_set_overcommit(struct sysdev_class *class, |
5516 | struct sysdev_class_attribute *attr, |
5517 | const char *buf, size_t count) |
5518 | { |
5519 | unsigned long val; |
5520 | int err; |
5521 | |
5522 | err = strict_strtoul(buf, 10, &val); |
5523 | if (err) |
5524 | return err; |
5525 | if (val > 1) |
5526 | return -EINVAL; |
5527 | |
5528 | spin_lock(&perf_resource_lock); |
5529 | perf_overcommit = val; |
5530 | spin_unlock(&perf_resource_lock); |
5531 | |
5532 | return count; |
5533 | } |
5534 | |
5535 | static SYSDEV_CLASS_ATTR( |
5536 | reserve_percpu, |
5537 | 0644, |
5538 | perf_show_reserve_percpu, |
5539 | perf_set_reserve_percpu |
5540 | ); |
5541 | |
5542 | static SYSDEV_CLASS_ATTR( |
5543 | overcommit, |
5544 | 0644, |
5545 | perf_show_overcommit, |
5546 | perf_set_overcommit |
5547 | ); |
5548 | |
5549 | static struct attribute *perfclass_attrs[] = { |
5550 | &attr_reserve_percpu.attr, |
5551 | &attr_overcommit.attr, |
5552 | NULL |
5553 | }; |
5554 | |
5555 | static struct attribute_group perfclass_attr_group = { |
5556 | .attrs = perfclass_attrs, |
5557 | .name = "perf_events", |
5558 | }; |
5559 | |
5560 | static int __init perf_event_sysfs_init(void) |
5561 | { |
5562 | return sysfs_create_group(&cpu_sysdev_class.kset.kobj, |
5563 | &perfclass_attr_group); |
5564 | } |
5565 | device_initcall(perf_event_sysfs_init); |
5566 |
Branches:
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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