]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * Performance events core code: | |
3 | * | |
4 | * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> | |
5 | * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar | |
6 | * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> | |
7 | * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> | |
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/idr.h> | |
17 | #include <linux/file.h> | |
18 | #include <linux/poll.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/hash.h> | |
21 | #include <linux/sysfs.h> | |
22 | #include <linux/dcache.h> | |
23 | #include <linux/percpu.h> | |
24 | #include <linux/ptrace.h> | |
25 | #include <linux/reboot.h> | |
26 | #include <linux/vmstat.h> | |
27 | #include <linux/device.h> | |
28 | #include <linux/export.h> | |
29 | #include <linux/vmalloc.h> | |
30 | #include <linux/hardirq.h> | |
31 | #include <linux/rculist.h> | |
32 | #include <linux/uaccess.h> | |
33 | #include <linux/syscalls.h> | |
34 | #include <linux/anon_inodes.h> | |
35 | #include <linux/kernel_stat.h> | |
36 | #include <linux/perf_event.h> | |
37 | #include <linux/ftrace_event.h> | |
38 | #include <linux/hw_breakpoint.h> | |
39 | ||
40 | #include "internal.h" | |
41 | ||
42 | #include <asm/irq_regs.h> | |
43 | ||
44 | struct remote_function_call { | |
45 | struct task_struct *p; | |
46 | int (*func)(void *info); | |
47 | void *info; | |
48 | int ret; | |
49 | }; | |
50 | ||
51 | static void remote_function(void *data) | |
52 | { | |
53 | struct remote_function_call *tfc = data; | |
54 | struct task_struct *p = tfc->p; | |
55 | ||
56 | if (p) { | |
57 | tfc->ret = -EAGAIN; | |
58 | if (task_cpu(p) != smp_processor_id() || !task_curr(p)) | |
59 | return; | |
60 | } | |
61 | ||
62 | tfc->ret = tfc->func(tfc->info); | |
63 | } | |
64 | ||
65 | /** | |
66 | * task_function_call - call a function on the cpu on which a task runs | |
67 | * @p: the task to evaluate | |
68 | * @func: the function to be called | |
69 | * @info: the function call argument | |
70 | * | |
71 | * Calls the function @func when the task is currently running. This might | |
72 | * be on the current CPU, which just calls the function directly | |
73 | * | |
74 | * returns: @func return value, or | |
75 | * -ESRCH - when the process isn't running | |
76 | * -EAGAIN - when the process moved away | |
77 | */ | |
78 | static int | |
79 | task_function_call(struct task_struct *p, int (*func) (void *info), void *info) | |
80 | { | |
81 | struct remote_function_call data = { | |
82 | .p = p, | |
83 | .func = func, | |
84 | .info = info, | |
85 | .ret = -ESRCH, /* No such (running) process */ | |
86 | }; | |
87 | ||
88 | if (task_curr(p)) | |
89 | smp_call_function_single(task_cpu(p), remote_function, &data, 1); | |
90 | ||
91 | return data.ret; | |
92 | } | |
93 | ||
94 | /** | |
95 | * cpu_function_call - call a function on the cpu | |
96 | * @func: the function to be called | |
97 | * @info: the function call argument | |
98 | * | |
99 | * Calls the function @func on the remote cpu. | |
100 | * | |
101 | * returns: @func return value or -ENXIO when the cpu is offline | |
102 | */ | |
103 | static int cpu_function_call(int cpu, int (*func) (void *info), void *info) | |
104 | { | |
105 | struct remote_function_call data = { | |
106 | .p = NULL, | |
107 | .func = func, | |
108 | .info = info, | |
109 | .ret = -ENXIO, /* No such CPU */ | |
110 | }; | |
111 | ||
112 | smp_call_function_single(cpu, remote_function, &data, 1); | |
113 | ||
114 | return data.ret; | |
115 | } | |
116 | ||
117 | #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ | |
118 | PERF_FLAG_FD_OUTPUT |\ | |
119 | PERF_FLAG_PID_CGROUP) | |
120 | ||
121 | enum event_type_t { | |
122 | EVENT_FLEXIBLE = 0x1, | |
123 | EVENT_PINNED = 0x2, | |
124 | EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, | |
125 | }; | |
126 | ||
127 | /* | |
128 | * perf_sched_events : >0 events exist | |
129 | * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu | |
130 | */ | |
131 | struct static_key_deferred perf_sched_events __read_mostly; | |
132 | static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); | |
133 | ||
134 | static atomic_t nr_mmap_events __read_mostly; | |
135 | static atomic_t nr_comm_events __read_mostly; | |
136 | static atomic_t nr_task_events __read_mostly; | |
137 | ||
138 | static LIST_HEAD(pmus); | |
139 | static DEFINE_MUTEX(pmus_lock); | |
140 | static struct srcu_struct pmus_srcu; | |
141 | ||
142 | /* | |
143 | * perf event paranoia level: | |
144 | * -1 - not paranoid at all | |
145 | * 0 - disallow raw tracepoint access for unpriv | |
146 | * 1 - disallow cpu events for unpriv | |
147 | * 2 - disallow kernel profiling for unpriv | |
148 | */ | |
149 | int sysctl_perf_event_paranoid __read_mostly = 1; | |
150 | ||
151 | /* Minimum for 512 kiB + 1 user control page */ | |
152 | int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ | |
153 | ||
154 | /* | |
155 | * max perf event sample rate | |
156 | */ | |
157 | #define DEFAULT_MAX_SAMPLE_RATE 100000 | |
158 | int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; | |
159 | static int max_samples_per_tick __read_mostly = | |
160 | DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); | |
161 | ||
162 | int perf_proc_update_handler(struct ctl_table *table, int write, | |
163 | void __user *buffer, size_t *lenp, | |
164 | loff_t *ppos) | |
165 | { | |
166 | int ret = proc_dointvec(table, write, buffer, lenp, ppos); | |
167 | ||
168 | if (ret || !write) | |
169 | return ret; | |
170 | ||
171 | max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); | |
172 | ||
173 | return 0; | |
174 | } | |
175 | ||
176 | static atomic64_t perf_event_id; | |
177 | ||
178 | static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, | |
179 | enum event_type_t event_type); | |
180 | ||
181 | static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, | |
182 | enum event_type_t event_type, | |
183 | struct task_struct *task); | |
184 | ||
185 | static void update_context_time(struct perf_event_context *ctx); | |
186 | static u64 perf_event_time(struct perf_event *event); | |
187 | ||
188 | static void ring_buffer_attach(struct perf_event *event, | |
189 | struct ring_buffer *rb); | |
190 | ||
191 | void __weak perf_event_print_debug(void) { } | |
192 | ||
193 | extern __weak const char *perf_pmu_name(void) | |
194 | { | |
195 | return "pmu"; | |
196 | } | |
197 | ||
198 | static inline u64 perf_clock(void) | |
199 | { | |
200 | return local_clock(); | |
201 | } | |
202 | ||
203 | static inline struct perf_cpu_context * | |
204 | __get_cpu_context(struct perf_event_context *ctx) | |
205 | { | |
206 | return this_cpu_ptr(ctx->pmu->pmu_cpu_context); | |
207 | } | |
208 | ||
209 | static void perf_ctx_lock(struct perf_cpu_context *cpuctx, | |
210 | struct perf_event_context *ctx) | |
211 | { | |
212 | raw_spin_lock(&cpuctx->ctx.lock); | |
213 | if (ctx) | |
214 | raw_spin_lock(&ctx->lock); | |
215 | } | |
216 | ||
217 | static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, | |
218 | struct perf_event_context *ctx) | |
219 | { | |
220 | if (ctx) | |
221 | raw_spin_unlock(&ctx->lock); | |
222 | raw_spin_unlock(&cpuctx->ctx.lock); | |
223 | } | |
224 | ||
225 | #ifdef CONFIG_CGROUP_PERF | |
226 | ||
227 | /* | |
228 | * Must ensure cgroup is pinned (css_get) before calling | |
229 | * this function. In other words, we cannot call this function | |
230 | * if there is no cgroup event for the current CPU context. | |
231 | */ | |
232 | static inline struct perf_cgroup * | |
233 | perf_cgroup_from_task(struct task_struct *task) | |
234 | { | |
235 | return container_of(task_subsys_state(task, perf_subsys_id), | |
236 | struct perf_cgroup, css); | |
237 | } | |
238 | ||
239 | static inline bool | |
240 | perf_cgroup_match(struct perf_event *event) | |
241 | { | |
242 | struct perf_event_context *ctx = event->ctx; | |
243 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
244 | ||
245 | return !event->cgrp || event->cgrp == cpuctx->cgrp; | |
246 | } | |
247 | ||
248 | static inline void perf_get_cgroup(struct perf_event *event) | |
249 | { | |
250 | css_get(&event->cgrp->css); | |
251 | } | |
252 | ||
253 | static inline void perf_put_cgroup(struct perf_event *event) | |
254 | { | |
255 | css_put(&event->cgrp->css); | |
256 | } | |
257 | ||
258 | static inline void perf_detach_cgroup(struct perf_event *event) | |
259 | { | |
260 | perf_put_cgroup(event); | |
261 | event->cgrp = NULL; | |
262 | } | |
263 | ||
264 | static inline int is_cgroup_event(struct perf_event *event) | |
265 | { | |
266 | return event->cgrp != NULL; | |
267 | } | |
268 | ||
269 | static inline u64 perf_cgroup_event_time(struct perf_event *event) | |
270 | { | |
271 | struct perf_cgroup_info *t; | |
272 | ||
273 | t = per_cpu_ptr(event->cgrp->info, event->cpu); | |
274 | return t->time; | |
275 | } | |
276 | ||
277 | static inline void __update_cgrp_time(struct perf_cgroup *cgrp) | |
278 | { | |
279 | struct perf_cgroup_info *info; | |
280 | u64 now; | |
281 | ||
282 | now = perf_clock(); | |
283 | ||
284 | info = this_cpu_ptr(cgrp->info); | |
285 | ||
286 | info->time += now - info->timestamp; | |
287 | info->timestamp = now; | |
288 | } | |
289 | ||
290 | static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) | |
291 | { | |
292 | struct perf_cgroup *cgrp_out = cpuctx->cgrp; | |
293 | if (cgrp_out) | |
294 | __update_cgrp_time(cgrp_out); | |
295 | } | |
296 | ||
297 | static inline void update_cgrp_time_from_event(struct perf_event *event) | |
298 | { | |
299 | struct perf_cgroup *cgrp; | |
300 | ||
301 | /* | |
302 | * ensure we access cgroup data only when needed and | |
303 | * when we know the cgroup is pinned (css_get) | |
304 | */ | |
305 | if (!is_cgroup_event(event)) | |
306 | return; | |
307 | ||
308 | cgrp = perf_cgroup_from_task(current); | |
309 | /* | |
310 | * Do not update time when cgroup is not active | |
311 | */ | |
312 | if (cgrp == event->cgrp) | |
313 | __update_cgrp_time(event->cgrp); | |
314 | } | |
315 | ||
316 | static inline void | |
317 | perf_cgroup_set_timestamp(struct task_struct *task, | |
318 | struct perf_event_context *ctx) | |
319 | { | |
320 | struct perf_cgroup *cgrp; | |
321 | struct perf_cgroup_info *info; | |
322 | ||
323 | /* | |
324 | * ctx->lock held by caller | |
325 | * ensure we do not access cgroup data | |
326 | * unless we have the cgroup pinned (css_get) | |
327 | */ | |
328 | if (!task || !ctx->nr_cgroups) | |
329 | return; | |
330 | ||
331 | cgrp = perf_cgroup_from_task(task); | |
332 | info = this_cpu_ptr(cgrp->info); | |
333 | info->timestamp = ctx->timestamp; | |
334 | } | |
335 | ||
336 | #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ | |
337 | #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ | |
338 | ||
339 | /* | |
340 | * reschedule events based on the cgroup constraint of task. | |
341 | * | |
342 | * mode SWOUT : schedule out everything | |
343 | * mode SWIN : schedule in based on cgroup for next | |
344 | */ | |
345 | void perf_cgroup_switch(struct task_struct *task, int mode) | |
346 | { | |
347 | struct perf_cpu_context *cpuctx; | |
348 | struct pmu *pmu; | |
349 | unsigned long flags; | |
350 | ||
351 | /* | |
352 | * disable interrupts to avoid geting nr_cgroup | |
353 | * changes via __perf_event_disable(). Also | |
354 | * avoids preemption. | |
355 | */ | |
356 | local_irq_save(flags); | |
357 | ||
358 | /* | |
359 | * we reschedule only in the presence of cgroup | |
360 | * constrained events. | |
361 | */ | |
362 | rcu_read_lock(); | |
363 | ||
364 | list_for_each_entry_rcu(pmu, &pmus, entry) { | |
365 | cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); | |
366 | ||
367 | /* | |
368 | * perf_cgroup_events says at least one | |
369 | * context on this CPU has cgroup events. | |
370 | * | |
371 | * ctx->nr_cgroups reports the number of cgroup | |
372 | * events for a context. | |
373 | */ | |
374 | if (cpuctx->ctx.nr_cgroups > 0) { | |
375 | perf_ctx_lock(cpuctx, cpuctx->task_ctx); | |
376 | perf_pmu_disable(cpuctx->ctx.pmu); | |
377 | ||
378 | if (mode & PERF_CGROUP_SWOUT) { | |
379 | cpu_ctx_sched_out(cpuctx, EVENT_ALL); | |
380 | /* | |
381 | * must not be done before ctxswout due | |
382 | * to event_filter_match() in event_sched_out() | |
383 | */ | |
384 | cpuctx->cgrp = NULL; | |
385 | } | |
386 | ||
387 | if (mode & PERF_CGROUP_SWIN) { | |
388 | WARN_ON_ONCE(cpuctx->cgrp); | |
389 | /* set cgrp before ctxsw in to | |
390 | * allow event_filter_match() to not | |
391 | * have to pass task around | |
392 | */ | |
393 | cpuctx->cgrp = perf_cgroup_from_task(task); | |
394 | cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); | |
395 | } | |
396 | perf_pmu_enable(cpuctx->ctx.pmu); | |
397 | perf_ctx_unlock(cpuctx, cpuctx->task_ctx); | |
398 | } | |
399 | } | |
400 | ||
401 | rcu_read_unlock(); | |
402 | ||
403 | local_irq_restore(flags); | |
404 | } | |
405 | ||
406 | static inline void perf_cgroup_sched_out(struct task_struct *task, | |
407 | struct task_struct *next) | |
408 | { | |
409 | struct perf_cgroup *cgrp1; | |
410 | struct perf_cgroup *cgrp2 = NULL; | |
411 | ||
412 | /* | |
413 | * we come here when we know perf_cgroup_events > 0 | |
414 | */ | |
415 | cgrp1 = perf_cgroup_from_task(task); | |
416 | ||
417 | /* | |
418 | * next is NULL when called from perf_event_enable_on_exec() | |
419 | * that will systematically cause a cgroup_switch() | |
420 | */ | |
421 | if (next) | |
422 | cgrp2 = perf_cgroup_from_task(next); | |
423 | ||
424 | /* | |
425 | * only schedule out current cgroup events if we know | |
426 | * that we are switching to a different cgroup. Otherwise, | |
427 | * do no touch the cgroup events. | |
428 | */ | |
429 | if (cgrp1 != cgrp2) | |
430 | perf_cgroup_switch(task, PERF_CGROUP_SWOUT); | |
431 | } | |
432 | ||
433 | static inline void perf_cgroup_sched_in(struct task_struct *prev, | |
434 | struct task_struct *task) | |
435 | { | |
436 | struct perf_cgroup *cgrp1; | |
437 | struct perf_cgroup *cgrp2 = NULL; | |
438 | ||
439 | /* | |
440 | * we come here when we know perf_cgroup_events > 0 | |
441 | */ | |
442 | cgrp1 = perf_cgroup_from_task(task); | |
443 | ||
444 | /* prev can never be NULL */ | |
445 | cgrp2 = perf_cgroup_from_task(prev); | |
446 | ||
447 | /* | |
448 | * only need to schedule in cgroup events if we are changing | |
449 | * cgroup during ctxsw. Cgroup events were not scheduled | |
450 | * out of ctxsw out if that was not the case. | |
451 | */ | |
452 | if (cgrp1 != cgrp2) | |
453 | perf_cgroup_switch(task, PERF_CGROUP_SWIN); | |
454 | } | |
455 | ||
456 | static inline int perf_cgroup_connect(int fd, struct perf_event *event, | |
457 | struct perf_event_attr *attr, | |
458 | struct perf_event *group_leader) | |
459 | { | |
460 | struct perf_cgroup *cgrp; | |
461 | struct cgroup_subsys_state *css; | |
462 | struct file *file; | |
463 | int ret = 0, fput_needed; | |
464 | ||
465 | file = fget_light(fd, &fput_needed); | |
466 | if (!file) | |
467 | return -EBADF; | |
468 | ||
469 | css = cgroup_css_from_dir(file, perf_subsys_id); | |
470 | if (IS_ERR(css)) { | |
471 | ret = PTR_ERR(css); | |
472 | goto out; | |
473 | } | |
474 | ||
475 | cgrp = container_of(css, struct perf_cgroup, css); | |
476 | event->cgrp = cgrp; | |
477 | ||
478 | /* must be done before we fput() the file */ | |
479 | perf_get_cgroup(event); | |
480 | ||
481 | /* | |
482 | * all events in a group must monitor | |
483 | * the same cgroup because a task belongs | |
484 | * to only one perf cgroup at a time | |
485 | */ | |
486 | if (group_leader && group_leader->cgrp != cgrp) { | |
487 | perf_detach_cgroup(event); | |
488 | ret = -EINVAL; | |
489 | } | |
490 | out: | |
491 | fput_light(file, fput_needed); | |
492 | return ret; | |
493 | } | |
494 | ||
495 | static inline void | |
496 | perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) | |
497 | { | |
498 | struct perf_cgroup_info *t; | |
499 | t = per_cpu_ptr(event->cgrp->info, event->cpu); | |
500 | event->shadow_ctx_time = now - t->timestamp; | |
501 | } | |
502 | ||
503 | static inline void | |
504 | perf_cgroup_defer_enabled(struct perf_event *event) | |
505 | { | |
506 | /* | |
507 | * when the current task's perf cgroup does not match | |
508 | * the event's, we need to remember to call the | |
509 | * perf_mark_enable() function the first time a task with | |
510 | * a matching perf cgroup is scheduled in. | |
511 | */ | |
512 | if (is_cgroup_event(event) && !perf_cgroup_match(event)) | |
513 | event->cgrp_defer_enabled = 1; | |
514 | } | |
515 | ||
516 | static inline void | |
517 | perf_cgroup_mark_enabled(struct perf_event *event, | |
518 | struct perf_event_context *ctx) | |
519 | { | |
520 | struct perf_event *sub; | |
521 | u64 tstamp = perf_event_time(event); | |
522 | ||
523 | if (!event->cgrp_defer_enabled) | |
524 | return; | |
525 | ||
526 | event->cgrp_defer_enabled = 0; | |
527 | ||
528 | event->tstamp_enabled = tstamp - event->total_time_enabled; | |
529 | list_for_each_entry(sub, &event->sibling_list, group_entry) { | |
530 | if (sub->state >= PERF_EVENT_STATE_INACTIVE) { | |
531 | sub->tstamp_enabled = tstamp - sub->total_time_enabled; | |
532 | sub->cgrp_defer_enabled = 0; | |
533 | } | |
534 | } | |
535 | } | |
536 | #else /* !CONFIG_CGROUP_PERF */ | |
537 | ||
538 | static inline bool | |
539 | perf_cgroup_match(struct perf_event *event) | |
540 | { | |
541 | return true; | |
542 | } | |
543 | ||
544 | static inline void perf_detach_cgroup(struct perf_event *event) | |
545 | {} | |
546 | ||
547 | static inline int is_cgroup_event(struct perf_event *event) | |
548 | { | |
549 | return 0; | |
550 | } | |
551 | ||
552 | static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) | |
553 | { | |
554 | return 0; | |
555 | } | |
556 | ||
557 | static inline void update_cgrp_time_from_event(struct perf_event *event) | |
558 | { | |
559 | } | |
560 | ||
561 | static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) | |
562 | { | |
563 | } | |
564 | ||
565 | static inline void perf_cgroup_sched_out(struct task_struct *task, | |
566 | struct task_struct *next) | |
567 | { | |
568 | } | |
569 | ||
570 | static inline void perf_cgroup_sched_in(struct task_struct *prev, | |
571 | struct task_struct *task) | |
572 | { | |
573 | } | |
574 | ||
575 | static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, | |
576 | struct perf_event_attr *attr, | |
577 | struct perf_event *group_leader) | |
578 | { | |
579 | return -EINVAL; | |
580 | } | |
581 | ||
582 | static inline void | |
583 | perf_cgroup_set_timestamp(struct task_struct *task, | |
584 | struct perf_event_context *ctx) | |
585 | { | |
586 | } | |
587 | ||
588 | void | |
589 | perf_cgroup_switch(struct task_struct *task, struct task_struct *next) | |
590 | { | |
591 | } | |
592 | ||
593 | static inline void | |
594 | perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) | |
595 | { | |
596 | } | |
597 | ||
598 | static inline u64 perf_cgroup_event_time(struct perf_event *event) | |
599 | { | |
600 | return 0; | |
601 | } | |
602 | ||
603 | static inline void | |
604 | perf_cgroup_defer_enabled(struct perf_event *event) | |
605 | { | |
606 | } | |
607 | ||
608 | static inline void | |
609 | perf_cgroup_mark_enabled(struct perf_event *event, | |
610 | struct perf_event_context *ctx) | |
611 | { | |
612 | } | |
613 | #endif | |
614 | ||
615 | void perf_pmu_disable(struct pmu *pmu) | |
616 | { | |
617 | int *count = this_cpu_ptr(pmu->pmu_disable_count); | |
618 | if (!(*count)++) | |
619 | pmu->pmu_disable(pmu); | |
620 | } | |
621 | ||
622 | void perf_pmu_enable(struct pmu *pmu) | |
623 | { | |
624 | int *count = this_cpu_ptr(pmu->pmu_disable_count); | |
625 | if (!--(*count)) | |
626 | pmu->pmu_enable(pmu); | |
627 | } | |
628 | ||
629 | static DEFINE_PER_CPU(struct list_head, rotation_list); | |
630 | ||
631 | /* | |
632 | * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized | |
633 | * because they're strictly cpu affine and rotate_start is called with IRQs | |
634 | * disabled, while rotate_context is called from IRQ context. | |
635 | */ | |
636 | static void perf_pmu_rotate_start(struct pmu *pmu) | |
637 | { | |
638 | struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); | |
639 | struct list_head *head = &__get_cpu_var(rotation_list); | |
640 | ||
641 | WARN_ON(!irqs_disabled()); | |
642 | ||
643 | if (list_empty(&cpuctx->rotation_list)) | |
644 | list_add(&cpuctx->rotation_list, head); | |
645 | } | |
646 | ||
647 | static void get_ctx(struct perf_event_context *ctx) | |
648 | { | |
649 | WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); | |
650 | } | |
651 | ||
652 | static void put_ctx(struct perf_event_context *ctx) | |
653 | { | |
654 | if (atomic_dec_and_test(&ctx->refcount)) { | |
655 | if (ctx->parent_ctx) | |
656 | put_ctx(ctx->parent_ctx); | |
657 | if (ctx->task) | |
658 | put_task_struct(ctx->task); | |
659 | kfree_rcu(ctx, rcu_head); | |
660 | } | |
661 | } | |
662 | ||
663 | static void unclone_ctx(struct perf_event_context *ctx) | |
664 | { | |
665 | if (ctx->parent_ctx) { | |
666 | put_ctx(ctx->parent_ctx); | |
667 | ctx->parent_ctx = NULL; | |
668 | } | |
669 | } | |
670 | ||
671 | static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) | |
672 | { | |
673 | /* | |
674 | * only top level events have the pid namespace they were created in | |
675 | */ | |
676 | if (event->parent) | |
677 | event = event->parent; | |
678 | ||
679 | return task_tgid_nr_ns(p, event->ns); | |
680 | } | |
681 | ||
682 | static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) | |
683 | { | |
684 | /* | |
685 | * only top level events have the pid namespace they were created in | |
686 | */ | |
687 | if (event->parent) | |
688 | event = event->parent; | |
689 | ||
690 | return task_pid_nr_ns(p, event->ns); | |
691 | } | |
692 | ||
693 | /* | |
694 | * If we inherit events we want to return the parent event id | |
695 | * to userspace. | |
696 | */ | |
697 | static u64 primary_event_id(struct perf_event *event) | |
698 | { | |
699 | u64 id = event->id; | |
700 | ||
701 | if (event->parent) | |
702 | id = event->parent->id; | |
703 | ||
704 | return id; | |
705 | } | |
706 | ||
707 | /* | |
708 | * Get the perf_event_context for a task and lock it. | |
709 | * This has to cope with with the fact that until it is locked, | |
710 | * the context could get moved to another task. | |
711 | */ | |
712 | static struct perf_event_context * | |
713 | perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) | |
714 | { | |
715 | struct perf_event_context *ctx; | |
716 | ||
717 | rcu_read_lock(); | |
718 | retry: | |
719 | ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); | |
720 | if (ctx) { | |
721 | /* | |
722 | * If this context is a clone of another, it might | |
723 | * get swapped for another underneath us by | |
724 | * perf_event_task_sched_out, though the | |
725 | * rcu_read_lock() protects us from any context | |
726 | * getting freed. Lock the context and check if it | |
727 | * got swapped before we could get the lock, and retry | |
728 | * if so. If we locked the right context, then it | |
729 | * can't get swapped on us any more. | |
730 | */ | |
731 | raw_spin_lock_irqsave(&ctx->lock, *flags); | |
732 | if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { | |
733 | raw_spin_unlock_irqrestore(&ctx->lock, *flags); | |
734 | goto retry; | |
735 | } | |
736 | ||
737 | if (!atomic_inc_not_zero(&ctx->refcount)) { | |
738 | raw_spin_unlock_irqrestore(&ctx->lock, *flags); | |
739 | ctx = NULL; | |
740 | } | |
741 | } | |
742 | rcu_read_unlock(); | |
743 | return ctx; | |
744 | } | |
745 | ||
746 | /* | |
747 | * Get the context for a task and increment its pin_count so it | |
748 | * can't get swapped to another task. This also increments its | |
749 | * reference count so that the context can't get freed. | |
750 | */ | |
751 | static struct perf_event_context * | |
752 | perf_pin_task_context(struct task_struct *task, int ctxn) | |
753 | { | |
754 | struct perf_event_context *ctx; | |
755 | unsigned long flags; | |
756 | ||
757 | ctx = perf_lock_task_context(task, ctxn, &flags); | |
758 | if (ctx) { | |
759 | ++ctx->pin_count; | |
760 | raw_spin_unlock_irqrestore(&ctx->lock, flags); | |
761 | } | |
762 | return ctx; | |
763 | } | |
764 | ||
765 | static void perf_unpin_context(struct perf_event_context *ctx) | |
766 | { | |
767 | unsigned long flags; | |
768 | ||
769 | raw_spin_lock_irqsave(&ctx->lock, flags); | |
770 | --ctx->pin_count; | |
771 | raw_spin_unlock_irqrestore(&ctx->lock, flags); | |
772 | } | |
773 | ||
774 | /* | |
775 | * Update the record of the current time in a context. | |
776 | */ | |
777 | static void update_context_time(struct perf_event_context *ctx) | |
778 | { | |
779 | u64 now = perf_clock(); | |
780 | ||
781 | ctx->time += now - ctx->timestamp; | |
782 | ctx->timestamp = now; | |
783 | } | |
784 | ||
785 | static u64 perf_event_time(struct perf_event *event) | |
786 | { | |
787 | struct perf_event_context *ctx = event->ctx; | |
788 | ||
789 | if (is_cgroup_event(event)) | |
790 | return perf_cgroup_event_time(event); | |
791 | ||
792 | return ctx ? ctx->time : 0; | |
793 | } | |
794 | ||
795 | /* | |
796 | * Update the total_time_enabled and total_time_running fields for a event. | |
797 | * The caller of this function needs to hold the ctx->lock. | |
798 | */ | |
799 | static void update_event_times(struct perf_event *event) | |
800 | { | |
801 | struct perf_event_context *ctx = event->ctx; | |
802 | u64 run_end; | |
803 | ||
804 | if (event->state < PERF_EVENT_STATE_INACTIVE || | |
805 | event->group_leader->state < PERF_EVENT_STATE_INACTIVE) | |
806 | return; | |
807 | /* | |
808 | * in cgroup mode, time_enabled represents | |
809 | * the time the event was enabled AND active | |
810 | * tasks were in the monitored cgroup. This is | |
811 | * independent of the activity of the context as | |
812 | * there may be a mix of cgroup and non-cgroup events. | |
813 | * | |
814 | * That is why we treat cgroup events differently | |
815 | * here. | |
816 | */ | |
817 | if (is_cgroup_event(event)) | |
818 | run_end = perf_cgroup_event_time(event); | |
819 | else if (ctx->is_active) | |
820 | run_end = ctx->time; | |
821 | else | |
822 | run_end = event->tstamp_stopped; | |
823 | ||
824 | event->total_time_enabled = run_end - event->tstamp_enabled; | |
825 | ||
826 | if (event->state == PERF_EVENT_STATE_INACTIVE) | |
827 | run_end = event->tstamp_stopped; | |
828 | else | |
829 | run_end = perf_event_time(event); | |
830 | ||
831 | event->total_time_running = run_end - event->tstamp_running; | |
832 | ||
833 | } | |
834 | ||
835 | /* | |
836 | * Update total_time_enabled and total_time_running for all events in a group. | |
837 | */ | |
838 | static void update_group_times(struct perf_event *leader) | |
839 | { | |
840 | struct perf_event *event; | |
841 | ||
842 | update_event_times(leader); | |
843 | list_for_each_entry(event, &leader->sibling_list, group_entry) | |
844 | update_event_times(event); | |
845 | } | |
846 | ||
847 | static struct list_head * | |
848 | ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) | |
849 | { | |
850 | if (event->attr.pinned) | |
851 | return &ctx->pinned_groups; | |
852 | else | |
853 | return &ctx->flexible_groups; | |
854 | } | |
855 | ||
856 | /* | |
857 | * Add a event from the lists for its context. | |
858 | * Must be called with ctx->mutex and ctx->lock held. | |
859 | */ | |
860 | static void | |
861 | list_add_event(struct perf_event *event, struct perf_event_context *ctx) | |
862 | { | |
863 | WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); | |
864 | event->attach_state |= PERF_ATTACH_CONTEXT; | |
865 | ||
866 | /* | |
867 | * If we're a stand alone event or group leader, we go to the context | |
868 | * list, group events are kept attached to the group so that | |
869 | * perf_group_detach can, at all times, locate all siblings. | |
870 | */ | |
871 | if (event->group_leader == event) { | |
872 | struct list_head *list; | |
873 | ||
874 | if (is_software_event(event)) | |
875 | event->group_flags |= PERF_GROUP_SOFTWARE; | |
876 | ||
877 | list = ctx_group_list(event, ctx); | |
878 | list_add_tail(&event->group_entry, list); | |
879 | } | |
880 | ||
881 | if (is_cgroup_event(event)) | |
882 | ctx->nr_cgroups++; | |
883 | ||
884 | list_add_rcu(&event->event_entry, &ctx->event_list); | |
885 | if (!ctx->nr_events) | |
886 | perf_pmu_rotate_start(ctx->pmu); | |
887 | ctx->nr_events++; | |
888 | if (event->attr.inherit_stat) | |
889 | ctx->nr_stat++; | |
890 | } | |
891 | ||
892 | /* | |
893 | * Called at perf_event creation and when events are attached/detached from a | |
894 | * group. | |
895 | */ | |
896 | static void perf_event__read_size(struct perf_event *event) | |
897 | { | |
898 | int entry = sizeof(u64); /* value */ | |
899 | int size = 0; | |
900 | int nr = 1; | |
901 | ||
902 | if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) | |
903 | size += sizeof(u64); | |
904 | ||
905 | if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) | |
906 | size += sizeof(u64); | |
907 | ||
908 | if (event->attr.read_format & PERF_FORMAT_ID) | |
909 | entry += sizeof(u64); | |
910 | ||
911 | if (event->attr.read_format & PERF_FORMAT_GROUP) { | |
912 | nr += event->group_leader->nr_siblings; | |
913 | size += sizeof(u64); | |
914 | } | |
915 | ||
916 | size += entry * nr; | |
917 | event->read_size = size; | |
918 | } | |
919 | ||
920 | static void perf_event__header_size(struct perf_event *event) | |
921 | { | |
922 | struct perf_sample_data *data; | |
923 | u64 sample_type = event->attr.sample_type; | |
924 | u16 size = 0; | |
925 | ||
926 | perf_event__read_size(event); | |
927 | ||
928 | if (sample_type & PERF_SAMPLE_IP) | |
929 | size += sizeof(data->ip); | |
930 | ||
931 | if (sample_type & PERF_SAMPLE_ADDR) | |
932 | size += sizeof(data->addr); | |
933 | ||
934 | if (sample_type & PERF_SAMPLE_PERIOD) | |
935 | size += sizeof(data->period); | |
936 | ||
937 | if (sample_type & PERF_SAMPLE_READ) | |
938 | size += event->read_size; | |
939 | ||
940 | event->header_size = size; | |
941 | } | |
942 | ||
943 | static void perf_event__id_header_size(struct perf_event *event) | |
944 | { | |
945 | struct perf_sample_data *data; | |
946 | u64 sample_type = event->attr.sample_type; | |
947 | u16 size = 0; | |
948 | ||
949 | if (sample_type & PERF_SAMPLE_TID) | |
950 | size += sizeof(data->tid_entry); | |
951 | ||
952 | if (sample_type & PERF_SAMPLE_TIME) | |
953 | size += sizeof(data->time); | |
954 | ||
955 | if (sample_type & PERF_SAMPLE_ID) | |
956 | size += sizeof(data->id); | |
957 | ||
958 | if (sample_type & PERF_SAMPLE_STREAM_ID) | |
959 | size += sizeof(data->stream_id); | |
960 | ||
961 | if (sample_type & PERF_SAMPLE_CPU) | |
962 | size += sizeof(data->cpu_entry); | |
963 | ||
964 | event->id_header_size = size; | |
965 | } | |
966 | ||
967 | static void perf_group_attach(struct perf_event *event) | |
968 | { | |
969 | struct perf_event *group_leader = event->group_leader, *pos; | |
970 | ||
971 | /* | |
972 | * We can have double attach due to group movement in perf_event_open. | |
973 | */ | |
974 | if (event->attach_state & PERF_ATTACH_GROUP) | |
975 | return; | |
976 | ||
977 | event->attach_state |= PERF_ATTACH_GROUP; | |
978 | ||
979 | if (group_leader == event) | |
980 | return; | |
981 | ||
982 | if (group_leader->group_flags & PERF_GROUP_SOFTWARE && | |
983 | !is_software_event(event)) | |
984 | group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; | |
985 | ||
986 | list_add_tail(&event->group_entry, &group_leader->sibling_list); | |
987 | group_leader->nr_siblings++; | |
988 | ||
989 | perf_event__header_size(group_leader); | |
990 | ||
991 | list_for_each_entry(pos, &group_leader->sibling_list, group_entry) | |
992 | perf_event__header_size(pos); | |
993 | } | |
994 | ||
995 | /* | |
996 | * Remove a event from the lists for its context. | |
997 | * Must be called with ctx->mutex and ctx->lock held. | |
998 | */ | |
999 | static void | |
1000 | list_del_event(struct perf_event *event, struct perf_event_context *ctx) | |
1001 | { | |
1002 | struct perf_cpu_context *cpuctx; | |
1003 | /* | |
1004 | * We can have double detach due to exit/hot-unplug + close. | |
1005 | */ | |
1006 | if (!(event->attach_state & PERF_ATTACH_CONTEXT)) | |
1007 | return; | |
1008 | ||
1009 | event->attach_state &= ~PERF_ATTACH_CONTEXT; | |
1010 | ||
1011 | if (is_cgroup_event(event)) { | |
1012 | ctx->nr_cgroups--; | |
1013 | cpuctx = __get_cpu_context(ctx); | |
1014 | /* | |
1015 | * if there are no more cgroup events | |
1016 | * then cler cgrp to avoid stale pointer | |
1017 | * in update_cgrp_time_from_cpuctx() | |
1018 | */ | |
1019 | if (!ctx->nr_cgroups) | |
1020 | cpuctx->cgrp = NULL; | |
1021 | } | |
1022 | ||
1023 | ctx->nr_events--; | |
1024 | if (event->attr.inherit_stat) | |
1025 | ctx->nr_stat--; | |
1026 | ||
1027 | list_del_rcu(&event->event_entry); | |
1028 | ||
1029 | if (event->group_leader == event) | |
1030 | list_del_init(&event->group_entry); | |
1031 | ||
1032 | update_group_times(event); | |
1033 | ||
1034 | /* | |
1035 | * If event was in error state, then keep it | |
1036 | * that way, otherwise bogus counts will be | |
1037 | * returned on read(). The only way to get out | |
1038 | * of error state is by explicit re-enabling | |
1039 | * of the event | |
1040 | */ | |
1041 | if (event->state > PERF_EVENT_STATE_OFF) | |
1042 | event->state = PERF_EVENT_STATE_OFF; | |
1043 | } | |
1044 | ||
1045 | static void perf_group_detach(struct perf_event *event) | |
1046 | { | |
1047 | struct perf_event *sibling, *tmp; | |
1048 | struct list_head *list = NULL; | |
1049 | ||
1050 | /* | |
1051 | * We can have double detach due to exit/hot-unplug + close. | |
1052 | */ | |
1053 | if (!(event->attach_state & PERF_ATTACH_GROUP)) | |
1054 | return; | |
1055 | ||
1056 | event->attach_state &= ~PERF_ATTACH_GROUP; | |
1057 | ||
1058 | /* | |
1059 | * If this is a sibling, remove it from its group. | |
1060 | */ | |
1061 | if (event->group_leader != event) { | |
1062 | list_del_init(&event->group_entry); | |
1063 | event->group_leader->nr_siblings--; | |
1064 | goto out; | |
1065 | } | |
1066 | ||
1067 | if (!list_empty(&event->group_entry)) | |
1068 | list = &event->group_entry; | |
1069 | ||
1070 | /* | |
1071 | * If this was a group event with sibling events then | |
1072 | * upgrade the siblings to singleton events by adding them | |
1073 | * to whatever list we are on. | |
1074 | */ | |
1075 | list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { | |
1076 | if (list) | |
1077 | list_move_tail(&sibling->group_entry, list); | |
1078 | sibling->group_leader = sibling; | |
1079 | ||
1080 | /* Inherit group flags from the previous leader */ | |
1081 | sibling->group_flags = event->group_flags; | |
1082 | } | |
1083 | ||
1084 | out: | |
1085 | perf_event__header_size(event->group_leader); | |
1086 | ||
1087 | list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) | |
1088 | perf_event__header_size(tmp); | |
1089 | } | |
1090 | ||
1091 | static inline int | |
1092 | event_filter_match(struct perf_event *event) | |
1093 | { | |
1094 | return (event->cpu == -1 || event->cpu == smp_processor_id()) | |
1095 | && perf_cgroup_match(event); | |
1096 | } | |
1097 | ||
1098 | static void | |
1099 | event_sched_out(struct perf_event *event, | |
1100 | struct perf_cpu_context *cpuctx, | |
1101 | struct perf_event_context *ctx) | |
1102 | { | |
1103 | u64 tstamp = perf_event_time(event); | |
1104 | u64 delta; | |
1105 | /* | |
1106 | * An event which could not be activated because of | |
1107 | * filter mismatch still needs to have its timings | |
1108 | * maintained, otherwise bogus information is return | |
1109 | * via read() for time_enabled, time_running: | |
1110 | */ | |
1111 | if (event->state == PERF_EVENT_STATE_INACTIVE | |
1112 | && !event_filter_match(event)) { | |
1113 | delta = tstamp - event->tstamp_stopped; | |
1114 | event->tstamp_running += delta; | |
1115 | event->tstamp_stopped = tstamp; | |
1116 | } | |
1117 | ||
1118 | if (event->state != PERF_EVENT_STATE_ACTIVE) | |
1119 | return; | |
1120 | ||
1121 | event->state = PERF_EVENT_STATE_INACTIVE; | |
1122 | if (event->pending_disable) { | |
1123 | event->pending_disable = 0; | |
1124 | event->state = PERF_EVENT_STATE_OFF; | |
1125 | } | |
1126 | event->tstamp_stopped = tstamp; | |
1127 | event->pmu->del(event, 0); | |
1128 | event->oncpu = -1; | |
1129 | ||
1130 | if (!is_software_event(event)) | |
1131 | cpuctx->active_oncpu--; | |
1132 | ctx->nr_active--; | |
1133 | if (event->attr.freq && event->attr.sample_freq) | |
1134 | ctx->nr_freq--; | |
1135 | if (event->attr.exclusive || !cpuctx->active_oncpu) | |
1136 | cpuctx->exclusive = 0; | |
1137 | } | |
1138 | ||
1139 | static void | |
1140 | group_sched_out(struct perf_event *group_event, | |
1141 | struct perf_cpu_context *cpuctx, | |
1142 | struct perf_event_context *ctx) | |
1143 | { | |
1144 | struct perf_event *event; | |
1145 | int state = group_event->state; | |
1146 | ||
1147 | event_sched_out(group_event, cpuctx, ctx); | |
1148 | ||
1149 | /* | |
1150 | * Schedule out siblings (if any): | |
1151 | */ | |
1152 | list_for_each_entry(event, &group_event->sibling_list, group_entry) | |
1153 | event_sched_out(event, cpuctx, ctx); | |
1154 | ||
1155 | if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) | |
1156 | cpuctx->exclusive = 0; | |
1157 | } | |
1158 | ||
1159 | /* | |
1160 | * Cross CPU call to remove a performance event | |
1161 | * | |
1162 | * We disable the event on the hardware level first. After that we | |
1163 | * remove it from the context list. | |
1164 | */ | |
1165 | static int __perf_remove_from_context(void *info) | |
1166 | { | |
1167 | struct perf_event *event = info; | |
1168 | struct perf_event_context *ctx = event->ctx; | |
1169 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
1170 | ||
1171 | raw_spin_lock(&ctx->lock); | |
1172 | event_sched_out(event, cpuctx, ctx); | |
1173 | list_del_event(event, ctx); | |
1174 | if (!ctx->nr_events && cpuctx->task_ctx == ctx) { | |
1175 | ctx->is_active = 0; | |
1176 | cpuctx->task_ctx = NULL; | |
1177 | } | |
1178 | raw_spin_unlock(&ctx->lock); | |
1179 | ||
1180 | return 0; | |
1181 | } | |
1182 | ||
1183 | ||
1184 | /* | |
1185 | * Remove the event from a task's (or a CPU's) list of events. | |
1186 | * | |
1187 | * CPU events are removed with a smp call. For task events we only | |
1188 | * call when the task is on a CPU. | |
1189 | * | |
1190 | * If event->ctx is a cloned context, callers must make sure that | |
1191 | * every task struct that event->ctx->task could possibly point to | |
1192 | * remains valid. This is OK when called from perf_release since | |
1193 | * that only calls us on the top-level context, which can't be a clone. | |
1194 | * When called from perf_event_exit_task, it's OK because the | |
1195 | * context has been detached from its task. | |
1196 | */ | |
1197 | static void perf_remove_from_context(struct perf_event *event) | |
1198 | { | |
1199 | struct perf_event_context *ctx = event->ctx; | |
1200 | struct task_struct *task = ctx->task; | |
1201 | ||
1202 | lockdep_assert_held(&ctx->mutex); | |
1203 | ||
1204 | if (!task) { | |
1205 | /* | |
1206 | * Per cpu events are removed via an smp call and | |
1207 | * the removal is always successful. | |
1208 | */ | |
1209 | cpu_function_call(event->cpu, __perf_remove_from_context, event); | |
1210 | return; | |
1211 | } | |
1212 | ||
1213 | retry: | |
1214 | if (!task_function_call(task, __perf_remove_from_context, event)) | |
1215 | return; | |
1216 | ||
1217 | raw_spin_lock_irq(&ctx->lock); | |
1218 | /* | |
1219 | * If we failed to find a running task, but find the context active now | |
1220 | * that we've acquired the ctx->lock, retry. | |
1221 | */ | |
1222 | if (ctx->is_active) { | |
1223 | raw_spin_unlock_irq(&ctx->lock); | |
1224 | goto retry; | |
1225 | } | |
1226 | ||
1227 | /* | |
1228 | * Since the task isn't running, its safe to remove the event, us | |
1229 | * holding the ctx->lock ensures the task won't get scheduled in. | |
1230 | */ | |
1231 | list_del_event(event, ctx); | |
1232 | raw_spin_unlock_irq(&ctx->lock); | |
1233 | } | |
1234 | ||
1235 | /* | |
1236 | * Cross CPU call to disable a performance event | |
1237 | */ | |
1238 | static int __perf_event_disable(void *info) | |
1239 | { | |
1240 | struct perf_event *event = info; | |
1241 | struct perf_event_context *ctx = event->ctx; | |
1242 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
1243 | ||
1244 | /* | |
1245 | * If this is a per-task event, need to check whether this | |
1246 | * event's task is the current task on this cpu. | |
1247 | * | |
1248 | * Can trigger due to concurrent perf_event_context_sched_out() | |
1249 | * flipping contexts around. | |
1250 | */ | |
1251 | if (ctx->task && cpuctx->task_ctx != ctx) | |
1252 | return -EINVAL; | |
1253 | ||
1254 | raw_spin_lock(&ctx->lock); | |
1255 | ||
1256 | /* | |
1257 | * If the event is on, turn it off. | |
1258 | * If it is in error state, leave it in error state. | |
1259 | */ | |
1260 | if (event->state >= PERF_EVENT_STATE_INACTIVE) { | |
1261 | update_context_time(ctx); | |
1262 | update_cgrp_time_from_event(event); | |
1263 | update_group_times(event); | |
1264 | if (event == event->group_leader) | |
1265 | group_sched_out(event, cpuctx, ctx); | |
1266 | else | |
1267 | event_sched_out(event, cpuctx, ctx); | |
1268 | event->state = PERF_EVENT_STATE_OFF; | |
1269 | } | |
1270 | ||
1271 | raw_spin_unlock(&ctx->lock); | |
1272 | ||
1273 | return 0; | |
1274 | } | |
1275 | ||
1276 | /* | |
1277 | * Disable a event. | |
1278 | * | |
1279 | * If event->ctx is a cloned context, callers must make sure that | |
1280 | * every task struct that event->ctx->task could possibly point to | |
1281 | * remains valid. This condition is satisifed when called through | |
1282 | * perf_event_for_each_child or perf_event_for_each because they | |
1283 | * hold the top-level event's child_mutex, so any descendant that | |
1284 | * goes to exit will block in sync_child_event. | |
1285 | * When called from perf_pending_event it's OK because event->ctx | |
1286 | * is the current context on this CPU and preemption is disabled, | |
1287 | * hence we can't get into perf_event_task_sched_out for this context. | |
1288 | */ | |
1289 | void perf_event_disable(struct perf_event *event) | |
1290 | { | |
1291 | struct perf_event_context *ctx = event->ctx; | |
1292 | struct task_struct *task = ctx->task; | |
1293 | ||
1294 | if (!task) { | |
1295 | /* | |
1296 | * Disable the event on the cpu that it's on | |
1297 | */ | |
1298 | cpu_function_call(event->cpu, __perf_event_disable, event); | |
1299 | return; | |
1300 | } | |
1301 | ||
1302 | retry: | |
1303 | if (!task_function_call(task, __perf_event_disable, event)) | |
1304 | return; | |
1305 | ||
1306 | raw_spin_lock_irq(&ctx->lock); | |
1307 | /* | |
1308 | * If the event is still active, we need to retry the cross-call. | |
1309 | */ | |
1310 | if (event->state == PERF_EVENT_STATE_ACTIVE) { | |
1311 | raw_spin_unlock_irq(&ctx->lock); | |
1312 | /* | |
1313 | * Reload the task pointer, it might have been changed by | |
1314 | * a concurrent perf_event_context_sched_out(). | |
1315 | */ | |
1316 | task = ctx->task; | |
1317 | goto retry; | |
1318 | } | |
1319 | ||
1320 | /* | |
1321 | * Since we have the lock this context can't be scheduled | |
1322 | * in, so we can change the state safely. | |
1323 | */ | |
1324 | if (event->state == PERF_EVENT_STATE_INACTIVE) { | |
1325 | update_group_times(event); | |
1326 | event->state = PERF_EVENT_STATE_OFF; | |
1327 | } | |
1328 | raw_spin_unlock_irq(&ctx->lock); | |
1329 | } | |
1330 | EXPORT_SYMBOL_GPL(perf_event_disable); | |
1331 | ||
1332 | static void perf_set_shadow_time(struct perf_event *event, | |
1333 | struct perf_event_context *ctx, | |
1334 | u64 tstamp) | |
1335 | { | |
1336 | /* | |
1337 | * use the correct time source for the time snapshot | |
1338 | * | |
1339 | * We could get by without this by leveraging the | |
1340 | * fact that to get to this function, the caller | |
1341 | * has most likely already called update_context_time() | |
1342 | * and update_cgrp_time_xx() and thus both timestamp | |
1343 | * are identical (or very close). Given that tstamp is, | |
1344 | * already adjusted for cgroup, we could say that: | |
1345 | * tstamp - ctx->timestamp | |
1346 | * is equivalent to | |
1347 | * tstamp - cgrp->timestamp. | |
1348 | * | |
1349 | * Then, in perf_output_read(), the calculation would | |
1350 | * work with no changes because: | |
1351 | * - event is guaranteed scheduled in | |
1352 | * - no scheduled out in between | |
1353 | * - thus the timestamp would be the same | |
1354 | * | |
1355 | * But this is a bit hairy. | |
1356 | * | |
1357 | * So instead, we have an explicit cgroup call to remain | |
1358 | * within the time time source all along. We believe it | |
1359 | * is cleaner and simpler to understand. | |
1360 | */ | |
1361 | if (is_cgroup_event(event)) | |
1362 | perf_cgroup_set_shadow_time(event, tstamp); | |
1363 | else | |
1364 | event->shadow_ctx_time = tstamp - ctx->timestamp; | |
1365 | } | |
1366 | ||
1367 | #define MAX_INTERRUPTS (~0ULL) | |
1368 | ||
1369 | static void perf_log_throttle(struct perf_event *event, int enable); | |
1370 | ||
1371 | static int | |
1372 | event_sched_in(struct perf_event *event, | |
1373 | struct perf_cpu_context *cpuctx, | |
1374 | struct perf_event_context *ctx) | |
1375 | { | |
1376 | u64 tstamp = perf_event_time(event); | |
1377 | ||
1378 | if (event->state <= PERF_EVENT_STATE_OFF) | |
1379 | return 0; | |
1380 | ||
1381 | event->state = PERF_EVENT_STATE_ACTIVE; | |
1382 | event->oncpu = smp_processor_id(); | |
1383 | ||
1384 | /* | |
1385 | * Unthrottle events, since we scheduled we might have missed several | |
1386 | * ticks already, also for a heavily scheduling task there is little | |
1387 | * guarantee it'll get a tick in a timely manner. | |
1388 | */ | |
1389 | if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { | |
1390 | perf_log_throttle(event, 1); | |
1391 | event->hw.interrupts = 0; | |
1392 | } | |
1393 | ||
1394 | /* | |
1395 | * The new state must be visible before we turn it on in the hardware: | |
1396 | */ | |
1397 | smp_wmb(); | |
1398 | ||
1399 | if (event->pmu->add(event, PERF_EF_START)) { | |
1400 | event->state = PERF_EVENT_STATE_INACTIVE; | |
1401 | event->oncpu = -1; | |
1402 | return -EAGAIN; | |
1403 | } | |
1404 | ||
1405 | event->tstamp_running += tstamp - event->tstamp_stopped; | |
1406 | ||
1407 | perf_set_shadow_time(event, ctx, tstamp); | |
1408 | ||
1409 | if (!is_software_event(event)) | |
1410 | cpuctx->active_oncpu++; | |
1411 | ctx->nr_active++; | |
1412 | if (event->attr.freq && event->attr.sample_freq) | |
1413 | ctx->nr_freq++; | |
1414 | ||
1415 | if (event->attr.exclusive) | |
1416 | cpuctx->exclusive = 1; | |
1417 | ||
1418 | return 0; | |
1419 | } | |
1420 | ||
1421 | static int | |
1422 | group_sched_in(struct perf_event *group_event, | |
1423 | struct perf_cpu_context *cpuctx, | |
1424 | struct perf_event_context *ctx) | |
1425 | { | |
1426 | struct perf_event *event, *partial_group = NULL; | |
1427 | struct pmu *pmu = group_event->pmu; | |
1428 | u64 now = ctx->time; | |
1429 | bool simulate = false; | |
1430 | ||
1431 | if (group_event->state == PERF_EVENT_STATE_OFF) | |
1432 | return 0; | |
1433 | ||
1434 | pmu->start_txn(pmu); | |
1435 | ||
1436 | if (event_sched_in(group_event, cpuctx, ctx)) { | |
1437 | pmu->cancel_txn(pmu); | |
1438 | return -EAGAIN; | |
1439 | } | |
1440 | ||
1441 | /* | |
1442 | * Schedule in siblings as one group (if any): | |
1443 | */ | |
1444 | list_for_each_entry(event, &group_event->sibling_list, group_entry) { | |
1445 | if (event_sched_in(event, cpuctx, ctx)) { | |
1446 | partial_group = event; | |
1447 | goto group_error; | |
1448 | } | |
1449 | } | |
1450 | ||
1451 | if (!pmu->commit_txn(pmu)) | |
1452 | return 0; | |
1453 | ||
1454 | group_error: | |
1455 | /* | |
1456 | * Groups can be scheduled in as one unit only, so undo any | |
1457 | * partial group before returning: | |
1458 | * The events up to the failed event are scheduled out normally, | |
1459 | * tstamp_stopped will be updated. | |
1460 | * | |
1461 | * The failed events and the remaining siblings need to have | |
1462 | * their timings updated as if they had gone thru event_sched_in() | |
1463 | * and event_sched_out(). This is required to get consistent timings | |
1464 | * across the group. This also takes care of the case where the group | |
1465 | * could never be scheduled by ensuring tstamp_stopped is set to mark | |
1466 | * the time the event was actually stopped, such that time delta | |
1467 | * calculation in update_event_times() is correct. | |
1468 | */ | |
1469 | list_for_each_entry(event, &group_event->sibling_list, group_entry) { | |
1470 | if (event == partial_group) | |
1471 | simulate = true; | |
1472 | ||
1473 | if (simulate) { | |
1474 | event->tstamp_running += now - event->tstamp_stopped; | |
1475 | event->tstamp_stopped = now; | |
1476 | } else { | |
1477 | event_sched_out(event, cpuctx, ctx); | |
1478 | } | |
1479 | } | |
1480 | event_sched_out(group_event, cpuctx, ctx); | |
1481 | ||
1482 | pmu->cancel_txn(pmu); | |
1483 | ||
1484 | return -EAGAIN; | |
1485 | } | |
1486 | ||
1487 | /* | |
1488 | * Work out whether we can put this event group on the CPU now. | |
1489 | */ | |
1490 | static int group_can_go_on(struct perf_event *event, | |
1491 | struct perf_cpu_context *cpuctx, | |
1492 | int can_add_hw) | |
1493 | { | |
1494 | /* | |
1495 | * Groups consisting entirely of software events can always go on. | |
1496 | */ | |
1497 | if (event->group_flags & PERF_GROUP_SOFTWARE) | |
1498 | return 1; | |
1499 | /* | |
1500 | * If an exclusive group is already on, no other hardware | |
1501 | * events can go on. | |
1502 | */ | |
1503 | if (cpuctx->exclusive) | |
1504 | return 0; | |
1505 | /* | |
1506 | * If this group is exclusive and there are already | |
1507 | * events on the CPU, it can't go on. | |
1508 | */ | |
1509 | if (event->attr.exclusive && cpuctx->active_oncpu) | |
1510 | return 0; | |
1511 | /* | |
1512 | * Otherwise, try to add it if all previous groups were able | |
1513 | * to go on. | |
1514 | */ | |
1515 | return can_add_hw; | |
1516 | } | |
1517 | ||
1518 | static void add_event_to_ctx(struct perf_event *event, | |
1519 | struct perf_event_context *ctx) | |
1520 | { | |
1521 | u64 tstamp = perf_event_time(event); | |
1522 | ||
1523 | list_add_event(event, ctx); | |
1524 | perf_group_attach(event); | |
1525 | event->tstamp_enabled = tstamp; | |
1526 | event->tstamp_running = tstamp; | |
1527 | event->tstamp_stopped = tstamp; | |
1528 | } | |
1529 | ||
1530 | static void task_ctx_sched_out(struct perf_event_context *ctx); | |
1531 | static void | |
1532 | ctx_sched_in(struct perf_event_context *ctx, | |
1533 | struct perf_cpu_context *cpuctx, | |
1534 | enum event_type_t event_type, | |
1535 | struct task_struct *task); | |
1536 | ||
1537 | static void perf_event_sched_in(struct perf_cpu_context *cpuctx, | |
1538 | struct perf_event_context *ctx, | |
1539 | struct task_struct *task) | |
1540 | { | |
1541 | cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); | |
1542 | if (ctx) | |
1543 | ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); | |
1544 | cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); | |
1545 | if (ctx) | |
1546 | ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); | |
1547 | } | |
1548 | ||
1549 | /* | |
1550 | * Cross CPU call to install and enable a performance event | |
1551 | * | |
1552 | * Must be called with ctx->mutex held | |
1553 | */ | |
1554 | static int __perf_install_in_context(void *info) | |
1555 | { | |
1556 | struct perf_event *event = info; | |
1557 | struct perf_event_context *ctx = event->ctx; | |
1558 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
1559 | struct perf_event_context *task_ctx = cpuctx->task_ctx; | |
1560 | struct task_struct *task = current; | |
1561 | ||
1562 | perf_ctx_lock(cpuctx, task_ctx); | |
1563 | perf_pmu_disable(cpuctx->ctx.pmu); | |
1564 | ||
1565 | /* | |
1566 | * If there was an active task_ctx schedule it out. | |
1567 | */ | |
1568 | if (task_ctx) | |
1569 | task_ctx_sched_out(task_ctx); | |
1570 | ||
1571 | /* | |
1572 | * If the context we're installing events in is not the | |
1573 | * active task_ctx, flip them. | |
1574 | */ | |
1575 | if (ctx->task && task_ctx != ctx) { | |
1576 | if (task_ctx) | |
1577 | raw_spin_unlock(&task_ctx->lock); | |
1578 | raw_spin_lock(&ctx->lock); | |
1579 | task_ctx = ctx; | |
1580 | } | |
1581 | ||
1582 | if (task_ctx) { | |
1583 | cpuctx->task_ctx = task_ctx; | |
1584 | task = task_ctx->task; | |
1585 | } | |
1586 | ||
1587 | cpu_ctx_sched_out(cpuctx, EVENT_ALL); | |
1588 | ||
1589 | update_context_time(ctx); | |
1590 | /* | |
1591 | * update cgrp time only if current cgrp | |
1592 | * matches event->cgrp. Must be done before | |
1593 | * calling add_event_to_ctx() | |
1594 | */ | |
1595 | update_cgrp_time_from_event(event); | |
1596 | ||
1597 | add_event_to_ctx(event, ctx); | |
1598 | ||
1599 | /* | |
1600 | * Schedule everything back in | |
1601 | */ | |
1602 | perf_event_sched_in(cpuctx, task_ctx, task); | |
1603 | ||
1604 | perf_pmu_enable(cpuctx->ctx.pmu); | |
1605 | perf_ctx_unlock(cpuctx, task_ctx); | |
1606 | ||
1607 | return 0; | |
1608 | } | |
1609 | ||
1610 | /* | |
1611 | * Attach a performance event to a context | |
1612 | * | |
1613 | * First we add the event to the list with the hardware enable bit | |
1614 | * in event->hw_config cleared. | |
1615 | * | |
1616 | * If the event is attached to a task which is on a CPU we use a smp | |
1617 | * call to enable it in the task context. The task might have been | |
1618 | * scheduled away, but we check this in the smp call again. | |
1619 | */ | |
1620 | static void | |
1621 | perf_install_in_context(struct perf_event_context *ctx, | |
1622 | struct perf_event *event, | |
1623 | int cpu) | |
1624 | { | |
1625 | struct task_struct *task = ctx->task; | |
1626 | ||
1627 | lockdep_assert_held(&ctx->mutex); | |
1628 | ||
1629 | event->ctx = ctx; | |
1630 | ||
1631 | if (!task) { | |
1632 | /* | |
1633 | * Per cpu events are installed via an smp call and | |
1634 | * the install is always successful. | |
1635 | */ | |
1636 | cpu_function_call(cpu, __perf_install_in_context, event); | |
1637 | return; | |
1638 | } | |
1639 | ||
1640 | retry: | |
1641 | if (!task_function_call(task, __perf_install_in_context, event)) | |
1642 | return; | |
1643 | ||
1644 | raw_spin_lock_irq(&ctx->lock); | |
1645 | /* | |
1646 | * If we failed to find a running task, but find the context active now | |
1647 | * that we've acquired the ctx->lock, retry. | |
1648 | */ | |
1649 | if (ctx->is_active) { | |
1650 | raw_spin_unlock_irq(&ctx->lock); | |
1651 | goto retry; | |
1652 | } | |
1653 | ||
1654 | /* | |
1655 | * Since the task isn't running, its safe to add the event, us holding | |
1656 | * the ctx->lock ensures the task won't get scheduled in. | |
1657 | */ | |
1658 | add_event_to_ctx(event, ctx); | |
1659 | raw_spin_unlock_irq(&ctx->lock); | |
1660 | } | |
1661 | ||
1662 | /* | |
1663 | * Put a event into inactive state and update time fields. | |
1664 | * Enabling the leader of a group effectively enables all | |
1665 | * the group members that aren't explicitly disabled, so we | |
1666 | * have to update their ->tstamp_enabled also. | |
1667 | * Note: this works for group members as well as group leaders | |
1668 | * since the non-leader members' sibling_lists will be empty. | |
1669 | */ | |
1670 | static void __perf_event_mark_enabled(struct perf_event *event) | |
1671 | { | |
1672 | struct perf_event *sub; | |
1673 | u64 tstamp = perf_event_time(event); | |
1674 | ||
1675 | event->state = PERF_EVENT_STATE_INACTIVE; | |
1676 | event->tstamp_enabled = tstamp - event->total_time_enabled; | |
1677 | list_for_each_entry(sub, &event->sibling_list, group_entry) { | |
1678 | if (sub->state >= PERF_EVENT_STATE_INACTIVE) | |
1679 | sub->tstamp_enabled = tstamp - sub->total_time_enabled; | |
1680 | } | |
1681 | } | |
1682 | ||
1683 | /* | |
1684 | * Cross CPU call to enable a performance event | |
1685 | */ | |
1686 | static int __perf_event_enable(void *info) | |
1687 | { | |
1688 | struct perf_event *event = info; | |
1689 | struct perf_event_context *ctx = event->ctx; | |
1690 | struct perf_event *leader = event->group_leader; | |
1691 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
1692 | int err; | |
1693 | ||
1694 | if (WARN_ON_ONCE(!ctx->is_active)) | |
1695 | return -EINVAL; | |
1696 | ||
1697 | raw_spin_lock(&ctx->lock); | |
1698 | update_context_time(ctx); | |
1699 | ||
1700 | if (event->state >= PERF_EVENT_STATE_INACTIVE) | |
1701 | goto unlock; | |
1702 | ||
1703 | /* | |
1704 | * set current task's cgroup time reference point | |
1705 | */ | |
1706 | perf_cgroup_set_timestamp(current, ctx); | |
1707 | ||
1708 | __perf_event_mark_enabled(event); | |
1709 | ||
1710 | if (!event_filter_match(event)) { | |
1711 | if (is_cgroup_event(event)) | |
1712 | perf_cgroup_defer_enabled(event); | |
1713 | goto unlock; | |
1714 | } | |
1715 | ||
1716 | /* | |
1717 | * If the event is in a group and isn't the group leader, | |
1718 | * then don't put it on unless the group is on. | |
1719 | */ | |
1720 | if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) | |
1721 | goto unlock; | |
1722 | ||
1723 | if (!group_can_go_on(event, cpuctx, 1)) { | |
1724 | err = -EEXIST; | |
1725 | } else { | |
1726 | if (event == leader) | |
1727 | err = group_sched_in(event, cpuctx, ctx); | |
1728 | else | |
1729 | err = event_sched_in(event, cpuctx, ctx); | |
1730 | } | |
1731 | ||
1732 | if (err) { | |
1733 | /* | |
1734 | * If this event can't go on and it's part of a | |
1735 | * group, then the whole group has to come off. | |
1736 | */ | |
1737 | if (leader != event) | |
1738 | group_sched_out(leader, cpuctx, ctx); | |
1739 | if (leader->attr.pinned) { | |
1740 | update_group_times(leader); | |
1741 | leader->state = PERF_EVENT_STATE_ERROR; | |
1742 | } | |
1743 | } | |
1744 | ||
1745 | unlock: | |
1746 | raw_spin_unlock(&ctx->lock); | |
1747 | ||
1748 | return 0; | |
1749 | } | |
1750 | ||
1751 | /* | |
1752 | * Enable a event. | |
1753 | * | |
1754 | * If event->ctx is a cloned context, callers must make sure that | |
1755 | * every task struct that event->ctx->task could possibly point to | |
1756 | * remains valid. This condition is satisfied when called through | |
1757 | * perf_event_for_each_child or perf_event_for_each as described | |
1758 | * for perf_event_disable. | |
1759 | */ | |
1760 | void perf_event_enable(struct perf_event *event) | |
1761 | { | |
1762 | struct perf_event_context *ctx = event->ctx; | |
1763 | struct task_struct *task = ctx->task; | |
1764 | ||
1765 | if (!task) { | |
1766 | /* | |
1767 | * Enable the event on the cpu that it's on | |
1768 | */ | |
1769 | cpu_function_call(event->cpu, __perf_event_enable, event); | |
1770 | return; | |
1771 | } | |
1772 | ||
1773 | raw_spin_lock_irq(&ctx->lock); | |
1774 | if (event->state >= PERF_EVENT_STATE_INACTIVE) | |
1775 | goto out; | |
1776 | ||
1777 | /* | |
1778 | * If the event is in error state, clear that first. | |
1779 | * That way, if we see the event in error state below, we | |
1780 | * know that it has gone back into error state, as distinct | |
1781 | * from the task having been scheduled away before the | |
1782 | * cross-call arrived. | |
1783 | */ | |
1784 | if (event->state == PERF_EVENT_STATE_ERROR) | |
1785 | event->state = PERF_EVENT_STATE_OFF; | |
1786 | ||
1787 | retry: | |
1788 | if (!ctx->is_active) { | |
1789 | __perf_event_mark_enabled(event); | |
1790 | goto out; | |
1791 | } | |
1792 | ||
1793 | raw_spin_unlock_irq(&ctx->lock); | |
1794 | ||
1795 | if (!task_function_call(task, __perf_event_enable, event)) | |
1796 | return; | |
1797 | ||
1798 | raw_spin_lock_irq(&ctx->lock); | |
1799 | ||
1800 | /* | |
1801 | * If the context is active and the event is still off, | |
1802 | * we need to retry the cross-call. | |
1803 | */ | |
1804 | if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) { | |
1805 | /* | |
1806 | * task could have been flipped by a concurrent | |
1807 | * perf_event_context_sched_out() | |
1808 | */ | |
1809 | task = ctx->task; | |
1810 | goto retry; | |
1811 | } | |
1812 | ||
1813 | out: | |
1814 | raw_spin_unlock_irq(&ctx->lock); | |
1815 | } | |
1816 | EXPORT_SYMBOL_GPL(perf_event_enable); | |
1817 | ||
1818 | int perf_event_refresh(struct perf_event *event, int refresh) | |
1819 | { | |
1820 | /* | |
1821 | * not supported on inherited events | |
1822 | */ | |
1823 | if (event->attr.inherit || !is_sampling_event(event)) | |
1824 | return -EINVAL; | |
1825 | ||
1826 | atomic_add(refresh, &event->event_limit); | |
1827 | perf_event_enable(event); | |
1828 | ||
1829 | return 0; | |
1830 | } | |
1831 | EXPORT_SYMBOL_GPL(perf_event_refresh); | |
1832 | ||
1833 | static void ctx_sched_out(struct perf_event_context *ctx, | |
1834 | struct perf_cpu_context *cpuctx, | |
1835 | enum event_type_t event_type) | |
1836 | { | |
1837 | struct perf_event *event; | |
1838 | int is_active = ctx->is_active; | |
1839 | ||
1840 | ctx->is_active &= ~event_type; | |
1841 | if (likely(!ctx->nr_events)) | |
1842 | return; | |
1843 | ||
1844 | update_context_time(ctx); | |
1845 | update_cgrp_time_from_cpuctx(cpuctx); | |
1846 | if (!ctx->nr_active) | |
1847 | return; | |
1848 | ||
1849 | perf_pmu_disable(ctx->pmu); | |
1850 | if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) { | |
1851 | list_for_each_entry(event, &ctx->pinned_groups, group_entry) | |
1852 | group_sched_out(event, cpuctx, ctx); | |
1853 | } | |
1854 | ||
1855 | if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) { | |
1856 | list_for_each_entry(event, &ctx->flexible_groups, group_entry) | |
1857 | group_sched_out(event, cpuctx, ctx); | |
1858 | } | |
1859 | perf_pmu_enable(ctx->pmu); | |
1860 | } | |
1861 | ||
1862 | /* | |
1863 | * Test whether two contexts are equivalent, i.e. whether they | |
1864 | * have both been cloned from the same version of the same context | |
1865 | * and they both have the same number of enabled events. | |
1866 | * If the number of enabled events is the same, then the set | |
1867 | * of enabled events should be the same, because these are both | |
1868 | * inherited contexts, therefore we can't access individual events | |
1869 | * in them directly with an fd; we can only enable/disable all | |
1870 | * events via prctl, or enable/disable all events in a family | |
1871 | * via ioctl, which will have the same effect on both contexts. | |
1872 | */ | |
1873 | static int context_equiv(struct perf_event_context *ctx1, | |
1874 | struct perf_event_context *ctx2) | |
1875 | { | |
1876 | return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx | |
1877 | && ctx1->parent_gen == ctx2->parent_gen | |
1878 | && !ctx1->pin_count && !ctx2->pin_count; | |
1879 | } | |
1880 | ||
1881 | static void __perf_event_sync_stat(struct perf_event *event, | |
1882 | struct perf_event *next_event) | |
1883 | { | |
1884 | u64 value; | |
1885 | ||
1886 | if (!event->attr.inherit_stat) | |
1887 | return; | |
1888 | ||
1889 | /* | |
1890 | * Update the event value, we cannot use perf_event_read() | |
1891 | * because we're in the middle of a context switch and have IRQs | |
1892 | * disabled, which upsets smp_call_function_single(), however | |
1893 | * we know the event must be on the current CPU, therefore we | |
1894 | * don't need to use it. | |
1895 | */ | |
1896 | switch (event->state) { | |
1897 | case PERF_EVENT_STATE_ACTIVE: | |
1898 | event->pmu->read(event); | |
1899 | /* fall-through */ | |
1900 | ||
1901 | case PERF_EVENT_STATE_INACTIVE: | |
1902 | update_event_times(event); | |
1903 | break; | |
1904 | ||
1905 | default: | |
1906 | break; | |
1907 | } | |
1908 | ||
1909 | /* | |
1910 | * In order to keep per-task stats reliable we need to flip the event | |
1911 | * values when we flip the contexts. | |
1912 | */ | |
1913 | value = local64_read(&next_event->count); | |
1914 | value = local64_xchg(&event->count, value); | |
1915 | local64_set(&next_event->count, value); | |
1916 | ||
1917 | swap(event->total_time_enabled, next_event->total_time_enabled); | |
1918 | swap(event->total_time_running, next_event->total_time_running); | |
1919 | ||
1920 | /* | |
1921 | * Since we swizzled the values, update the user visible data too. | |
1922 | */ | |
1923 | perf_event_update_userpage(event); | |
1924 | perf_event_update_userpage(next_event); | |
1925 | } | |
1926 | ||
1927 | #define list_next_entry(pos, member) \ | |
1928 | list_entry(pos->member.next, typeof(*pos), member) | |
1929 | ||
1930 | static void perf_event_sync_stat(struct perf_event_context *ctx, | |
1931 | struct perf_event_context *next_ctx) | |
1932 | { | |
1933 | struct perf_event *event, *next_event; | |
1934 | ||
1935 | if (!ctx->nr_stat) | |
1936 | return; | |
1937 | ||
1938 | update_context_time(ctx); | |
1939 | ||
1940 | event = list_first_entry(&ctx->event_list, | |
1941 | struct perf_event, event_entry); | |
1942 | ||
1943 | next_event = list_first_entry(&next_ctx->event_list, | |
1944 | struct perf_event, event_entry); | |
1945 | ||
1946 | while (&event->event_entry != &ctx->event_list && | |
1947 | &next_event->event_entry != &next_ctx->event_list) { | |
1948 | ||
1949 | __perf_event_sync_stat(event, next_event); | |
1950 | ||
1951 | event = list_next_entry(event, event_entry); | |
1952 | next_event = list_next_entry(next_event, event_entry); | |
1953 | } | |
1954 | } | |
1955 | ||
1956 | static void perf_event_context_sched_out(struct task_struct *task, int ctxn, | |
1957 | struct task_struct *next) | |
1958 | { | |
1959 | struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; | |
1960 | struct perf_event_context *next_ctx; | |
1961 | struct perf_event_context *parent; | |
1962 | struct perf_cpu_context *cpuctx; | |
1963 | int do_switch = 1; | |
1964 | ||
1965 | if (likely(!ctx)) | |
1966 | return; | |
1967 | ||
1968 | cpuctx = __get_cpu_context(ctx); | |
1969 | if (!cpuctx->task_ctx) | |
1970 | return; | |
1971 | ||
1972 | rcu_read_lock(); | |
1973 | parent = rcu_dereference(ctx->parent_ctx); | |
1974 | next_ctx = next->perf_event_ctxp[ctxn]; | |
1975 | if (parent && next_ctx && | |
1976 | rcu_dereference(next_ctx->parent_ctx) == parent) { | |
1977 | /* | |
1978 | * Looks like the two contexts are clones, so we might be | |
1979 | * able to optimize the context switch. We lock both | |
1980 | * contexts and check that they are clones under the | |
1981 | * lock (including re-checking that neither has been | |
1982 | * uncloned in the meantime). It doesn't matter which | |
1983 | * order we take the locks because no other cpu could | |
1984 | * be trying to lock both of these tasks. | |
1985 | */ | |
1986 | raw_spin_lock(&ctx->lock); | |
1987 | raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); | |
1988 | if (context_equiv(ctx, next_ctx)) { | |
1989 | /* | |
1990 | * XXX do we need a memory barrier of sorts | |
1991 | * wrt to rcu_dereference() of perf_event_ctxp | |
1992 | */ | |
1993 | task->perf_event_ctxp[ctxn] = next_ctx; | |
1994 | next->perf_event_ctxp[ctxn] = ctx; | |
1995 | ctx->task = next; | |
1996 | next_ctx->task = task; | |
1997 | do_switch = 0; | |
1998 | ||
1999 | perf_event_sync_stat(ctx, next_ctx); | |
2000 | } | |
2001 | raw_spin_unlock(&next_ctx->lock); | |
2002 | raw_spin_unlock(&ctx->lock); | |
2003 | } | |
2004 | rcu_read_unlock(); | |
2005 | ||
2006 | if (do_switch) { | |
2007 | raw_spin_lock(&ctx->lock); | |
2008 | ctx_sched_out(ctx, cpuctx, EVENT_ALL); | |
2009 | cpuctx->task_ctx = NULL; | |
2010 | raw_spin_unlock(&ctx->lock); | |
2011 | } | |
2012 | } | |
2013 | ||
2014 | #define for_each_task_context_nr(ctxn) \ | |
2015 | for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) | |
2016 | ||
2017 | /* | |
2018 | * Called from scheduler to remove the events of the current task, | |
2019 | * with interrupts disabled. | |
2020 | * | |
2021 | * We stop each event and update the event value in event->count. | |
2022 | * | |
2023 | * This does not protect us against NMI, but disable() | |
2024 | * sets the disabled bit in the control field of event _before_ | |
2025 | * accessing the event control register. If a NMI hits, then it will | |
2026 | * not restart the event. | |
2027 | */ | |
2028 | void __perf_event_task_sched_out(struct task_struct *task, | |
2029 | struct task_struct *next) | |
2030 | { | |
2031 | int ctxn; | |
2032 | ||
2033 | for_each_task_context_nr(ctxn) | |
2034 | perf_event_context_sched_out(task, ctxn, next); | |
2035 | ||
2036 | /* | |
2037 | * if cgroup events exist on this CPU, then we need | |
2038 | * to check if we have to switch out PMU state. | |
2039 | * cgroup event are system-wide mode only | |
2040 | */ | |
2041 | if (atomic_read(&__get_cpu_var(perf_cgroup_events))) | |
2042 | perf_cgroup_sched_out(task, next); | |
2043 | } | |
2044 | ||
2045 | static void task_ctx_sched_out(struct perf_event_context *ctx) | |
2046 | { | |
2047 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
2048 | ||
2049 | if (!cpuctx->task_ctx) | |
2050 | return; | |
2051 | ||
2052 | if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) | |
2053 | return; | |
2054 | ||
2055 | ctx_sched_out(ctx, cpuctx, EVENT_ALL); | |
2056 | cpuctx->task_ctx = NULL; | |
2057 | } | |
2058 | ||
2059 | /* | |
2060 | * Called with IRQs disabled | |
2061 | */ | |
2062 | static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, | |
2063 | enum event_type_t event_type) | |
2064 | { | |
2065 | ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); | |
2066 | } | |
2067 | ||
2068 | static void | |
2069 | ctx_pinned_sched_in(struct perf_event_context *ctx, | |
2070 | struct perf_cpu_context *cpuctx) | |
2071 | { | |
2072 | struct perf_event *event; | |
2073 | ||
2074 | list_for_each_entry(event, &ctx->pinned_groups, group_entry) { | |
2075 | if (event->state <= PERF_EVENT_STATE_OFF) | |
2076 | continue; | |
2077 | if (!event_filter_match(event)) | |
2078 | continue; | |
2079 | ||
2080 | /* may need to reset tstamp_enabled */ | |
2081 | if (is_cgroup_event(event)) | |
2082 | perf_cgroup_mark_enabled(event, ctx); | |
2083 | ||
2084 | if (group_can_go_on(event, cpuctx, 1)) | |
2085 | group_sched_in(event, cpuctx, ctx); | |
2086 | ||
2087 | /* | |
2088 | * If this pinned group hasn't been scheduled, | |
2089 | * put it in error state. | |
2090 | */ | |
2091 | if (event->state == PERF_EVENT_STATE_INACTIVE) { | |
2092 | update_group_times(event); | |
2093 | event->state = PERF_EVENT_STATE_ERROR; | |
2094 | } | |
2095 | } | |
2096 | } | |
2097 | ||
2098 | static void | |
2099 | ctx_flexible_sched_in(struct perf_event_context *ctx, | |
2100 | struct perf_cpu_context *cpuctx) | |
2101 | { | |
2102 | struct perf_event *event; | |
2103 | int can_add_hw = 1; | |
2104 | ||
2105 | list_for_each_entry(event, &ctx->flexible_groups, group_entry) { | |
2106 | /* Ignore events in OFF or ERROR state */ | |
2107 | if (event->state <= PERF_EVENT_STATE_OFF) | |
2108 | continue; | |
2109 | /* | |
2110 | * Listen to the 'cpu' scheduling filter constraint | |
2111 | * of events: | |
2112 | */ | |
2113 | if (!event_filter_match(event)) | |
2114 | continue; | |
2115 | ||
2116 | /* may need to reset tstamp_enabled */ | |
2117 | if (is_cgroup_event(event)) | |
2118 | perf_cgroup_mark_enabled(event, ctx); | |
2119 | ||
2120 | if (group_can_go_on(event, cpuctx, can_add_hw)) { | |
2121 | if (group_sched_in(event, cpuctx, ctx)) | |
2122 | can_add_hw = 0; | |
2123 | } | |
2124 | } | |
2125 | } | |
2126 | ||
2127 | static void | |
2128 | ctx_sched_in(struct perf_event_context *ctx, | |
2129 | struct perf_cpu_context *cpuctx, | |
2130 | enum event_type_t event_type, | |
2131 | struct task_struct *task) | |
2132 | { | |
2133 | u64 now; | |
2134 | int is_active = ctx->is_active; | |
2135 | ||
2136 | ctx->is_active |= event_type; | |
2137 | if (likely(!ctx->nr_events)) | |
2138 | return; | |
2139 | ||
2140 | now = perf_clock(); | |
2141 | ctx->timestamp = now; | |
2142 | perf_cgroup_set_timestamp(task, ctx); | |
2143 | /* | |
2144 | * First go through the list and put on any pinned groups | |
2145 | * in order to give them the best chance of going on. | |
2146 | */ | |
2147 | if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) | |
2148 | ctx_pinned_sched_in(ctx, cpuctx); | |
2149 | ||
2150 | /* Then walk through the lower prio flexible groups */ | |
2151 | if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) | |
2152 | ctx_flexible_sched_in(ctx, cpuctx); | |
2153 | } | |
2154 | ||
2155 | static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, | |
2156 | enum event_type_t event_type, | |
2157 | struct task_struct *task) | |
2158 | { | |
2159 | struct perf_event_context *ctx = &cpuctx->ctx; | |
2160 | ||
2161 | ctx_sched_in(ctx, cpuctx, event_type, task); | |
2162 | } | |
2163 | ||
2164 | static void perf_event_context_sched_in(struct perf_event_context *ctx, | |
2165 | struct task_struct *task) | |
2166 | { | |
2167 | struct perf_cpu_context *cpuctx; | |
2168 | ||
2169 | cpuctx = __get_cpu_context(ctx); | |
2170 | if (cpuctx->task_ctx == ctx) | |
2171 | return; | |
2172 | ||
2173 | perf_ctx_lock(cpuctx, ctx); | |
2174 | perf_pmu_disable(ctx->pmu); | |
2175 | /* | |
2176 | * We want to keep the following priority order: | |
2177 | * cpu pinned (that don't need to move), task pinned, | |
2178 | * cpu flexible, task flexible. | |
2179 | */ | |
2180 | cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); | |
2181 | ||
2182 | if (ctx->nr_events) | |
2183 | cpuctx->task_ctx = ctx; | |
2184 | ||
2185 | perf_event_sched_in(cpuctx, cpuctx->task_ctx, task); | |
2186 | ||
2187 | perf_pmu_enable(ctx->pmu); | |
2188 | perf_ctx_unlock(cpuctx, ctx); | |
2189 | ||
2190 | /* | |
2191 | * Since these rotations are per-cpu, we need to ensure the | |
2192 | * cpu-context we got scheduled on is actually rotating. | |
2193 | */ | |
2194 | perf_pmu_rotate_start(ctx->pmu); | |
2195 | } | |
2196 | ||
2197 | /* | |
2198 | * Called from scheduler to add the events of the current task | |
2199 | * with interrupts disabled. | |
2200 | * | |
2201 | * We restore the event value and then enable it. | |
2202 | * | |
2203 | * This does not protect us against NMI, but enable() | |
2204 | * sets the enabled bit in the control field of event _before_ | |
2205 | * accessing the event control register. If a NMI hits, then it will | |
2206 | * keep the event running. | |
2207 | */ | |
2208 | void __perf_event_task_sched_in(struct task_struct *prev, | |
2209 | struct task_struct *task) | |
2210 | { | |
2211 | struct perf_event_context *ctx; | |
2212 | int ctxn; | |
2213 | ||
2214 | for_each_task_context_nr(ctxn) { | |
2215 | ctx = task->perf_event_ctxp[ctxn]; | |
2216 | if (likely(!ctx)) | |
2217 | continue; | |
2218 | ||
2219 | perf_event_context_sched_in(ctx, task); | |
2220 | } | |
2221 | /* | |
2222 | * if cgroup events exist on this CPU, then we need | |
2223 | * to check if we have to switch in PMU state. | |
2224 | * cgroup event are system-wide mode only | |
2225 | */ | |
2226 | if (atomic_read(&__get_cpu_var(perf_cgroup_events))) | |
2227 | perf_cgroup_sched_in(prev, task); | |
2228 | } | |
2229 | ||
2230 | static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) | |
2231 | { | |
2232 | u64 frequency = event->attr.sample_freq; | |
2233 | u64 sec = NSEC_PER_SEC; | |
2234 | u64 divisor, dividend; | |
2235 | ||
2236 | int count_fls, nsec_fls, frequency_fls, sec_fls; | |
2237 | ||
2238 | count_fls = fls64(count); | |
2239 | nsec_fls = fls64(nsec); | |
2240 | frequency_fls = fls64(frequency); | |
2241 | sec_fls = 30; | |
2242 | ||
2243 | /* | |
2244 | * We got @count in @nsec, with a target of sample_freq HZ | |
2245 | * the target period becomes: | |
2246 | * | |
2247 | * @count * 10^9 | |
2248 | * period = ------------------- | |
2249 | * @nsec * sample_freq | |
2250 | * | |
2251 | */ | |
2252 | ||
2253 | /* | |
2254 | * Reduce accuracy by one bit such that @a and @b converge | |
2255 | * to a similar magnitude. | |
2256 | */ | |
2257 | #define REDUCE_FLS(a, b) \ | |
2258 | do { \ | |
2259 | if (a##_fls > b##_fls) { \ | |
2260 | a >>= 1; \ | |
2261 | a##_fls--; \ | |
2262 | } else { \ | |
2263 | b >>= 1; \ | |
2264 | b##_fls--; \ | |
2265 | } \ | |
2266 | } while (0) | |
2267 | ||
2268 | /* | |
2269 | * Reduce accuracy until either term fits in a u64, then proceed with | |
2270 | * the other, so that finally we can do a u64/u64 division. | |
2271 | */ | |
2272 | while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { | |
2273 | REDUCE_FLS(nsec, frequency); | |
2274 | REDUCE_FLS(sec, count); | |
2275 | } | |
2276 | ||
2277 | if (count_fls + sec_fls > 64) { | |
2278 | divisor = nsec * frequency; | |
2279 | ||
2280 | while (count_fls + sec_fls > 64) { | |
2281 | REDUCE_FLS(count, sec); | |
2282 | divisor >>= 1; | |
2283 | } | |
2284 | ||
2285 | dividend = count * sec; | |
2286 | } else { | |
2287 | dividend = count * sec; | |
2288 | ||
2289 | while (nsec_fls + frequency_fls > 64) { | |
2290 | REDUCE_FLS(nsec, frequency); | |
2291 | dividend >>= 1; | |
2292 | } | |
2293 | ||
2294 | divisor = nsec * frequency; | |
2295 | } | |
2296 | ||
2297 | if (!divisor) | |
2298 | return dividend; | |
2299 | ||
2300 | return div64_u64(dividend, divisor); | |
2301 | } | |
2302 | ||
2303 | static DEFINE_PER_CPU(int, perf_throttled_count); | |
2304 | static DEFINE_PER_CPU(u64, perf_throttled_seq); | |
2305 | ||
2306 | static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) | |
2307 | { | |
2308 | struct hw_perf_event *hwc = &event->hw; | |
2309 | s64 period, sample_period; | |
2310 | s64 delta; | |
2311 | ||
2312 | period = perf_calculate_period(event, nsec, count); | |
2313 | ||
2314 | delta = (s64)(period - hwc->sample_period); | |
2315 | delta = (delta + 7) / 8; /* low pass filter */ | |
2316 | ||
2317 | sample_period = hwc->sample_period + delta; | |
2318 | ||
2319 | if (!sample_period) | |
2320 | sample_period = 1; | |
2321 | ||
2322 | hwc->sample_period = sample_period; | |
2323 | ||
2324 | if (local64_read(&hwc->period_left) > 8*sample_period) { | |
2325 | if (disable) | |
2326 | event->pmu->stop(event, PERF_EF_UPDATE); | |
2327 | ||
2328 | local64_set(&hwc->period_left, 0); | |
2329 | ||
2330 | if (disable) | |
2331 | event->pmu->start(event, PERF_EF_RELOAD); | |
2332 | } | |
2333 | } | |
2334 | ||
2335 | /* | |
2336 | * combine freq adjustment with unthrottling to avoid two passes over the | |
2337 | * events. At the same time, make sure, having freq events does not change | |
2338 | * the rate of unthrottling as that would introduce bias. | |
2339 | */ | |
2340 | static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, | |
2341 | int needs_unthr) | |
2342 | { | |
2343 | struct perf_event *event; | |
2344 | struct hw_perf_event *hwc; | |
2345 | u64 now, period = TICK_NSEC; | |
2346 | s64 delta; | |
2347 | ||
2348 | /* | |
2349 | * only need to iterate over all events iff: | |
2350 | * - context have events in frequency mode (needs freq adjust) | |
2351 | * - there are events to unthrottle on this cpu | |
2352 | */ | |
2353 | if (!(ctx->nr_freq || needs_unthr)) | |
2354 | return; | |
2355 | ||
2356 | raw_spin_lock(&ctx->lock); | |
2357 | perf_pmu_disable(ctx->pmu); | |
2358 | ||
2359 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { | |
2360 | if (event->state != PERF_EVENT_STATE_ACTIVE) | |
2361 | continue; | |
2362 | ||
2363 | if (!event_filter_match(event)) | |
2364 | continue; | |
2365 | ||
2366 | hwc = &event->hw; | |
2367 | ||
2368 | if (needs_unthr && hwc->interrupts == MAX_INTERRUPTS) { | |
2369 | hwc->interrupts = 0; | |
2370 | perf_log_throttle(event, 1); | |
2371 | event->pmu->start(event, 0); | |
2372 | } | |
2373 | ||
2374 | if (!event->attr.freq || !event->attr.sample_freq) | |
2375 | continue; | |
2376 | ||
2377 | /* | |
2378 | * stop the event and update event->count | |
2379 | */ | |
2380 | event->pmu->stop(event, PERF_EF_UPDATE); | |
2381 | ||
2382 | now = local64_read(&event->count); | |
2383 | delta = now - hwc->freq_count_stamp; | |
2384 | hwc->freq_count_stamp = now; | |
2385 | ||
2386 | /* | |
2387 | * restart the event | |
2388 | * reload only if value has changed | |
2389 | * we have stopped the event so tell that | |
2390 | * to perf_adjust_period() to avoid stopping it | |
2391 | * twice. | |
2392 | */ | |
2393 | if (delta > 0) | |
2394 | perf_adjust_period(event, period, delta, false); | |
2395 | ||
2396 | event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); | |
2397 | } | |
2398 | ||
2399 | perf_pmu_enable(ctx->pmu); | |
2400 | raw_spin_unlock(&ctx->lock); | |
2401 | } | |
2402 | ||
2403 | /* | |
2404 | * Round-robin a context's events: | |
2405 | */ | |
2406 | static void rotate_ctx(struct perf_event_context *ctx) | |
2407 | { | |
2408 | /* | |
2409 | * Rotate the first entry last of non-pinned groups. Rotation might be | |
2410 | * disabled by the inheritance code. | |
2411 | */ | |
2412 | if (!ctx->rotate_disable) | |
2413 | list_rotate_left(&ctx->flexible_groups); | |
2414 | } | |
2415 | ||
2416 | /* | |
2417 | * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized | |
2418 | * because they're strictly cpu affine and rotate_start is called with IRQs | |
2419 | * disabled, while rotate_context is called from IRQ context. | |
2420 | */ | |
2421 | static void perf_rotate_context(struct perf_cpu_context *cpuctx) | |
2422 | { | |
2423 | struct perf_event_context *ctx = NULL; | |
2424 | int rotate = 0, remove = 1; | |
2425 | ||
2426 | if (cpuctx->ctx.nr_events) { | |
2427 | remove = 0; | |
2428 | if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) | |
2429 | rotate = 1; | |
2430 | } | |
2431 | ||
2432 | ctx = cpuctx->task_ctx; | |
2433 | if (ctx && ctx->nr_events) { | |
2434 | remove = 0; | |
2435 | if (ctx->nr_events != ctx->nr_active) | |
2436 | rotate = 1; | |
2437 | } | |
2438 | ||
2439 | if (!rotate) | |
2440 | goto done; | |
2441 | ||
2442 | perf_ctx_lock(cpuctx, cpuctx->task_ctx); | |
2443 | perf_pmu_disable(cpuctx->ctx.pmu); | |
2444 | ||
2445 | cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); | |
2446 | if (ctx) | |
2447 | ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); | |
2448 | ||
2449 | rotate_ctx(&cpuctx->ctx); | |
2450 | if (ctx) | |
2451 | rotate_ctx(ctx); | |
2452 | ||
2453 | perf_event_sched_in(cpuctx, ctx, current); | |
2454 | ||
2455 | perf_pmu_enable(cpuctx->ctx.pmu); | |
2456 | perf_ctx_unlock(cpuctx, cpuctx->task_ctx); | |
2457 | done: | |
2458 | if (remove) | |
2459 | list_del_init(&cpuctx->rotation_list); | |
2460 | } | |
2461 | ||
2462 | void perf_event_task_tick(void) | |
2463 | { | |
2464 | struct list_head *head = &__get_cpu_var(rotation_list); | |
2465 | struct perf_cpu_context *cpuctx, *tmp; | |
2466 | struct perf_event_context *ctx; | |
2467 | int throttled; | |
2468 | ||
2469 | WARN_ON(!irqs_disabled()); | |
2470 | ||
2471 | __this_cpu_inc(perf_throttled_seq); | |
2472 | throttled = __this_cpu_xchg(perf_throttled_count, 0); | |
2473 | ||
2474 | list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) { | |
2475 | ctx = &cpuctx->ctx; | |
2476 | perf_adjust_freq_unthr_context(ctx, throttled); | |
2477 | ||
2478 | ctx = cpuctx->task_ctx; | |
2479 | if (ctx) | |
2480 | perf_adjust_freq_unthr_context(ctx, throttled); | |
2481 | ||
2482 | if (cpuctx->jiffies_interval == 1 || | |
2483 | !(jiffies % cpuctx->jiffies_interval)) | |
2484 | perf_rotate_context(cpuctx); | |
2485 | } | |
2486 | } | |
2487 | ||
2488 | static int event_enable_on_exec(struct perf_event *event, | |
2489 | struct perf_event_context *ctx) | |
2490 | { | |
2491 | if (!event->attr.enable_on_exec) | |
2492 | return 0; | |
2493 | ||
2494 | event->attr.enable_on_exec = 0; | |
2495 | if (event->state >= PERF_EVENT_STATE_INACTIVE) | |
2496 | return 0; | |
2497 | ||
2498 | __perf_event_mark_enabled(event); | |
2499 | ||
2500 | return 1; | |
2501 | } | |
2502 | ||
2503 | /* | |
2504 | * Enable all of a task's events that have been marked enable-on-exec. | |
2505 | * This expects task == current. | |
2506 | */ | |
2507 | static void perf_event_enable_on_exec(struct perf_event_context *ctx) | |
2508 | { | |
2509 | struct perf_event *event; | |
2510 | unsigned long flags; | |
2511 | int enabled = 0; | |
2512 | int ret; | |
2513 | ||
2514 | local_irq_save(flags); | |
2515 | if (!ctx || !ctx->nr_events) | |
2516 | goto out; | |
2517 | ||
2518 | /* | |
2519 | * We must ctxsw out cgroup events to avoid conflict | |
2520 | * when invoking perf_task_event_sched_in() later on | |
2521 | * in this function. Otherwise we end up trying to | |
2522 | * ctxswin cgroup events which are already scheduled | |
2523 | * in. | |
2524 | */ | |
2525 | perf_cgroup_sched_out(current, NULL); | |
2526 | ||
2527 | raw_spin_lock(&ctx->lock); | |
2528 | task_ctx_sched_out(ctx); | |
2529 | ||
2530 | list_for_each_entry(event, &ctx->event_list, event_entry) { | |
2531 | ret = event_enable_on_exec(event, ctx); | |
2532 | if (ret) | |
2533 | enabled = 1; | |
2534 | } | |
2535 | ||
2536 | /* | |
2537 | * Unclone this context if we enabled any event. | |
2538 | */ | |
2539 | if (enabled) | |
2540 | unclone_ctx(ctx); | |
2541 | ||
2542 | raw_spin_unlock(&ctx->lock); | |
2543 | ||
2544 | /* | |
2545 | * Also calls ctxswin for cgroup events, if any: | |
2546 | */ | |
2547 | perf_event_context_sched_in(ctx, ctx->task); | |
2548 | out: | |
2549 | local_irq_restore(flags); | |
2550 | } | |
2551 | ||
2552 | /* | |
2553 | * Cross CPU call to read the hardware event | |
2554 | */ | |
2555 | static void __perf_event_read(void *info) | |
2556 | { | |
2557 | struct perf_event *event = info; | |
2558 | struct perf_event_context *ctx = event->ctx; | |
2559 | struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); | |
2560 | ||
2561 | /* | |
2562 | * If this is a task context, we need to check whether it is | |
2563 | * the current task context of this cpu. If not it has been | |
2564 | * scheduled out before the smp call arrived. In that case | |
2565 | * event->count would have been updated to a recent sample | |
2566 | * when the event was scheduled out. | |
2567 | */ | |
2568 | if (ctx->task && cpuctx->task_ctx != ctx) | |
2569 | return; | |
2570 | ||
2571 | raw_spin_lock(&ctx->lock); | |
2572 | if (ctx->is_active) { | |
2573 | update_context_time(ctx); | |
2574 | update_cgrp_time_from_event(event); | |
2575 | } | |
2576 | update_event_times(event); | |
2577 | if (event->state == PERF_EVENT_STATE_ACTIVE) | |
2578 | event->pmu->read(event); | |
2579 | raw_spin_unlock(&ctx->lock); | |
2580 | } | |
2581 | ||
2582 | static inline u64 perf_event_count(struct perf_event *event) | |
2583 | { | |
2584 | return local64_read(&event->count) + atomic64_read(&event->child_count); | |
2585 | } | |
2586 | ||
2587 | static u64 perf_event_read(struct perf_event *event) | |
2588 | { | |
2589 | /* | |
2590 | * If event is enabled and currently active on a CPU, update the | |
2591 | * value in the event structure: | |
2592 | */ | |
2593 | if (event->state == PERF_EVENT_STATE_ACTIVE) { | |
2594 | smp_call_function_single(event->oncpu, | |
2595 | __perf_event_read, event, 1); | |
2596 | } else if (event->state == PERF_EVENT_STATE_INACTIVE) { | |
2597 | struct perf_event_context *ctx = event->ctx; | |
2598 | unsigned long flags; | |
2599 | ||
2600 | raw_spin_lock_irqsave(&ctx->lock, flags); | |
2601 | /* | |
2602 | * may read while context is not active | |
2603 | * (e.g., thread is blocked), in that case | |
2604 | * we cannot update context time | |
2605 | */ | |
2606 | if (ctx->is_active) { | |
2607 | update_context_time(ctx); | |
2608 | update_cgrp_time_from_event(event); | |
2609 | } | |
2610 | update_event_times(event); | |
2611 | raw_spin_unlock_irqrestore(&ctx->lock, flags); | |
2612 | } | |
2613 | ||
2614 | return perf_event_count(event); | |
2615 | } | |
2616 | ||
2617 | /* | |
2618 | * Initialize the perf_event context in a task_struct: | |
2619 | */ | |
2620 | static void __perf_event_init_context(struct perf_event_context *ctx) | |
2621 | { | |
2622 | raw_spin_lock_init(&ctx->lock); | |
2623 | mutex_init(&ctx->mutex); | |
2624 | INIT_LIST_HEAD(&ctx->pinned_groups); | |
2625 | INIT_LIST_HEAD(&ctx->flexible_groups); | |
2626 | INIT_LIST_HEAD(&ctx->event_list); | |
2627 | atomic_set(&ctx->refcount, 1); | |
2628 | } | |
2629 | ||
2630 | static struct perf_event_context * | |
2631 | alloc_perf_context(struct pmu *pmu, struct task_struct *task) | |
2632 | { | |
2633 | struct perf_event_context *ctx; | |
2634 | ||
2635 | ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); | |
2636 | if (!ctx) | |
2637 | return NULL; | |
2638 | ||
2639 | __perf_event_init_context(ctx); | |
2640 | if (task) { | |
2641 | ctx->task = task; | |
2642 | get_task_struct(task); | |
2643 | } | |
2644 | ctx->pmu = pmu; | |
2645 | ||
2646 | return ctx; | |
2647 | } | |
2648 | ||
2649 | static struct task_struct * | |
2650 | find_lively_task_by_vpid(pid_t vpid) | |
2651 | { | |
2652 | struct task_struct *task; | |
2653 | int err; | |
2654 | ||
2655 | rcu_read_lock(); | |
2656 | if (!vpid) | |
2657 | task = current; | |
2658 | else | |
2659 | task = find_task_by_vpid(vpid); | |
2660 | if (task) | |
2661 | get_task_struct(task); | |
2662 | rcu_read_unlock(); | |
2663 | ||
2664 | if (!task) | |
2665 | return ERR_PTR(-ESRCH); | |
2666 | ||
2667 | /* Reuse ptrace permission checks for now. */ | |
2668 | err = -EACCES; | |
2669 | if (!ptrace_may_access(task, PTRACE_MODE_READ)) | |
2670 | goto errout; | |
2671 | ||
2672 | return task; | |
2673 | errout: | |
2674 | put_task_struct(task); | |
2675 | return ERR_PTR(err); | |
2676 | ||
2677 | } | |
2678 | ||
2679 | /* | |
2680 | * Returns a matching context with refcount and pincount. | |
2681 | */ | |
2682 | static struct perf_event_context * | |
2683 | find_get_context(struct pmu *pmu, struct task_struct *task, int cpu) | |
2684 | { | |
2685 | struct perf_event_context *ctx; | |
2686 | struct perf_cpu_context *cpuctx; | |
2687 | unsigned long flags; | |
2688 | int ctxn, err; | |
2689 | ||
2690 | if (!task) { | |
2691 | /* Must be root to operate on a CPU event: */ | |
2692 | if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) | |
2693 | return ERR_PTR(-EACCES); | |
2694 | ||
2695 | /* | |
2696 | * We could be clever and allow to attach a event to an | |
2697 | * offline CPU and activate it when the CPU comes up, but | |
2698 | * that's for later. | |
2699 | */ | |
2700 | if (!cpu_online(cpu)) | |
2701 | return ERR_PTR(-ENODEV); | |
2702 | ||
2703 | cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); | |
2704 | ctx = &cpuctx->ctx; | |
2705 | get_ctx(ctx); | |
2706 | ++ctx->pin_count; | |
2707 | ||
2708 | return ctx; | |
2709 | } | |
2710 | ||
2711 | err = -EINVAL; | |
2712 | ctxn = pmu->task_ctx_nr; | |
2713 | if (ctxn < 0) | |
2714 | goto errout; | |
2715 | ||
2716 | retry: | |
2717 | ctx = perf_lock_task_context(task, ctxn, &flags); | |
2718 | if (ctx) { | |
2719 | unclone_ctx(ctx); | |
2720 | ++ctx->pin_count; | |
2721 | raw_spin_unlock_irqrestore(&ctx->lock, flags); | |
2722 | } else { | |
2723 | ctx = alloc_perf_context(pmu, task); | |
2724 | err = -ENOMEM; | |
2725 | if (!ctx) | |
2726 | goto errout; | |
2727 | ||
2728 | err = 0; | |
2729 | mutex_lock(&task->perf_event_mutex); | |
2730 | /* | |
2731 | * If it has already passed perf_event_exit_task(). | |
2732 | * we must see PF_EXITING, it takes this mutex too. | |
2733 | */ | |
2734 | if (task->flags & PF_EXITING) | |
2735 | err = -ESRCH; | |
2736 | else if (task->perf_event_ctxp[ctxn]) | |
2737 | err = -EAGAIN; | |
2738 | else { | |
2739 | get_ctx(ctx); | |
2740 | ++ctx->pin_count; | |
2741 | rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); | |
2742 | } | |
2743 | mutex_unlock(&task->perf_event_mutex); | |
2744 | ||
2745 | if (unlikely(err)) { | |
2746 | put_ctx(ctx); | |
2747 | ||
2748 | if (err == -EAGAIN) | |
2749 | goto retry; | |
2750 | goto errout; | |
2751 | } | |
2752 | } | |
2753 | ||
2754 | return ctx; | |
2755 | ||
2756 | errout: | |
2757 | return ERR_PTR(err); | |
2758 | } | |
2759 | ||
2760 | static void perf_event_free_filter(struct perf_event *event); | |
2761 | ||
2762 | static void free_event_rcu(struct rcu_head *head) | |
2763 | { | |
2764 | struct perf_event *event; | |
2765 | ||
2766 | event = container_of(head, struct perf_event, rcu_head); | |
2767 | if (event->ns) | |
2768 | put_pid_ns(event->ns); | |
2769 | perf_event_free_filter(event); | |
2770 | kfree(event); | |
2771 | } | |
2772 | ||
2773 | static void ring_buffer_put(struct ring_buffer *rb); | |
2774 | ||
2775 | static void free_event(struct perf_event *event) | |
2776 | { | |
2777 | irq_work_sync(&event->pending); | |
2778 | ||
2779 | if (!event->parent) { | |
2780 | if (event->attach_state & PERF_ATTACH_TASK) | |
2781 | static_key_slow_dec_deferred(&perf_sched_events); | |
2782 | if (event->attr.mmap || event->attr.mmap_data) | |
2783 | atomic_dec(&nr_mmap_events); | |
2784 | if (event->attr.comm) | |
2785 | atomic_dec(&nr_comm_events); | |
2786 | if (event->attr.task) | |
2787 | atomic_dec(&nr_task_events); | |
2788 | if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) | |
2789 | put_callchain_buffers(); | |
2790 | if (is_cgroup_event(event)) { | |
2791 | atomic_dec(&per_cpu(perf_cgroup_events, event->cpu)); | |
2792 | static_key_slow_dec_deferred(&perf_sched_events); | |
2793 | } | |
2794 | } | |
2795 | ||
2796 | if (event->rb) { | |
2797 | ring_buffer_put(event->rb); | |
2798 | event->rb = NULL; | |
2799 | } | |
2800 | ||
2801 | if (is_cgroup_event(event)) | |
2802 | perf_detach_cgroup(event); | |
2803 | ||
2804 | if (event->destroy) | |
2805 | event->destroy(event); | |
2806 | ||
2807 | if (event->ctx) | |
2808 | put_ctx(event->ctx); | |
2809 | ||
2810 | call_rcu(&event->rcu_head, free_event_rcu); | |
2811 | } | |
2812 | ||
2813 | int perf_event_release_kernel(struct perf_event *event) | |
2814 | { | |
2815 | struct perf_event_context *ctx = event->ctx; | |
2816 | ||
2817 | WARN_ON_ONCE(ctx->parent_ctx); | |
2818 | /* | |
2819 | * There are two ways this annotation is useful: | |
2820 | * | |
2821 | * 1) there is a lock recursion from perf_event_exit_task | |
2822 | * see the comment there. | |
2823 | * | |
2824 | * 2) there is a lock-inversion with mmap_sem through | |
2825 | * perf_event_read_group(), which takes faults while | |
2826 | * holding ctx->mutex, however this is called after | |
2827 | * the last filedesc died, so there is no possibility | |
2828 | * to trigger the AB-BA case. | |
2829 | */ | |
2830 | mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING); | |
2831 | raw_spin_lock_irq(&ctx->lock); | |
2832 | perf_group_detach(event); | |
2833 | raw_spin_unlock_irq(&ctx->lock); | |
2834 | perf_remove_from_context(event); | |
2835 | mutex_unlock(&ctx->mutex); | |
2836 | ||
2837 | free_event(event); | |
2838 | ||
2839 | return 0; | |
2840 | } | |
2841 | EXPORT_SYMBOL_GPL(perf_event_release_kernel); | |
2842 | ||
2843 | /* | |
2844 | * Called when the last reference to the file is gone. | |
2845 | */ | |
2846 | static int perf_release(struct inode *inode, struct file *file) | |
2847 | { | |
2848 | struct perf_event *event = file->private_data; | |
2849 | struct task_struct *owner; | |
2850 | ||
2851 | file->private_data = NULL; | |
2852 | ||
2853 | rcu_read_lock(); | |
2854 | owner = ACCESS_ONCE(event->owner); | |
2855 | /* | |
2856 | * Matches the smp_wmb() in perf_event_exit_task(). If we observe | |
2857 | * !owner it means the list deletion is complete and we can indeed | |
2858 | * free this event, otherwise we need to serialize on | |
2859 | * owner->perf_event_mutex. | |
2860 | */ | |
2861 | smp_read_barrier_depends(); | |
2862 | if (owner) { | |
2863 | /* | |
2864 | * Since delayed_put_task_struct() also drops the last | |
2865 | * task reference we can safely take a new reference | |
2866 | * while holding the rcu_read_lock(). | |
2867 | */ | |
2868 | get_task_struct(owner); | |
2869 | } | |
2870 | rcu_read_unlock(); | |
2871 | ||
2872 | if (owner) { | |
2873 | mutex_lock(&owner->perf_event_mutex); | |
2874 | /* | |
2875 | * We have to re-check the event->owner field, if it is cleared | |
2876 | * we raced with perf_event_exit_task(), acquiring the mutex | |
2877 | * ensured they're done, and we can proceed with freeing the | |
2878 | * event. | |
2879 | */ | |
2880 | if (event->owner) | |
2881 | list_del_init(&event->owner_entry); | |
2882 | mutex_unlock(&owner->perf_event_mutex); | |
2883 | put_task_struct(owner); | |
2884 | } | |
2885 | ||
2886 | return perf_event_release_kernel(event); | |
2887 | } | |
2888 | ||
2889 | u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) | |
2890 | { | |
2891 | struct perf_event *child; | |
2892 | u64 total = 0; | |
2893 | ||
2894 | *enabled = 0; | |
2895 | *running = 0; | |
2896 | ||
2897 | mutex_lock(&event->child_mutex); | |
2898 | total += perf_event_read(event); | |
2899 | *enabled += event->total_time_enabled + | |
2900 | atomic64_read(&event->child_total_time_enabled); | |
2901 | *running += event->total_time_running + | |
2902 | atomic64_read(&event->child_total_time_running); | |
2903 | ||
2904 | list_for_each_entry(child, &event->child_list, child_list) { | |
2905 | total += perf_event_read(child); | |
2906 | *enabled += child->total_time_enabled; | |
2907 | *running += child->total_time_running; | |
2908 | } | |
2909 | mutex_unlock(&event->child_mutex); | |
2910 | ||
2911 | return total; | |
2912 | } | |
2913 | EXPORT_SYMBOL_GPL(perf_event_read_value); | |
2914 | ||
2915 | static int perf_event_read_group(struct perf_event *event, | |
2916 | u64 read_format, char __user *buf) | |
2917 | { | |
2918 | struct perf_event *leader = event->group_leader, *sub; | |
2919 | int n = 0, size = 0, ret = -EFAULT; | |
2920 | struct perf_event_context *ctx = leader->ctx; | |
2921 | u64 values[5]; | |
2922 | u64 count, enabled, running; | |
2923 | ||
2924 | mutex_lock(&ctx->mutex); | |
2925 | count = perf_event_read_value(leader, &enabled, &running); | |
2926 | ||
2927 | values[n++] = 1 + leader->nr_siblings; | |
2928 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) | |
2929 | values[n++] = enabled; | |
2930 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) | |
2931 | values[n++] = running; | |
2932 | values[n++] = count; | |
2933 | if (read_format & PERF_FORMAT_ID) | |
2934 | values[n++] = primary_event_id(leader); | |
2935 | ||
2936 | size = n * sizeof(u64); | |
2937 | ||
2938 | if (copy_to_user(buf, values, size)) | |
2939 | goto unlock; | |
2940 | ||
2941 | ret = size; | |
2942 | ||
2943 | list_for_each_entry(sub, &leader->sibling_list, group_entry) { | |
2944 | n = 0; | |
2945 | ||
2946 | values[n++] = perf_event_read_value(sub, &enabled, &running); | |
2947 | if (read_format & PERF_FORMAT_ID) | |
2948 | values[n++] = primary_event_id(sub); | |
2949 | ||
2950 | size = n * sizeof(u64); | |
2951 | ||
2952 | if (copy_to_user(buf + ret, values, size)) { | |
2953 | ret = -EFAULT; | |
2954 | goto unlock; | |
2955 | } | |
2956 | ||
2957 | ret += size; | |
2958 | } | |
2959 | unlock: | |
2960 | mutex_unlock(&ctx->mutex); | |
2961 | ||
2962 | return ret; | |
2963 | } | |
2964 | ||
2965 | static int perf_event_read_one(struct perf_event *event, | |
2966 | u64 read_format, char __user *buf) | |
2967 | { | |
2968 | u64 enabled, running; | |
2969 | u64 values[4]; | |
2970 | int n = 0; | |
2971 | ||
2972 | values[n++] = perf_event_read_value(event, &enabled, &running); | |
2973 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) | |
2974 | values[n++] = enabled; | |
2975 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) | |
2976 | values[n++] = running; | |
2977 | if (read_format & PERF_FORMAT_ID) | |
2978 | values[n++] = primary_event_id(event); | |
2979 | ||
2980 | if (copy_to_user(buf, values, n * sizeof(u64))) | |
2981 | return -EFAULT; | |
2982 | ||
2983 | return n * sizeof(u64); | |
2984 | } | |
2985 | ||
2986 | /* | |
2987 | * Read the performance event - simple non blocking version for now | |
2988 | */ | |
2989 | static ssize_t | |
2990 | perf_read_hw(struct perf_event *event, char __user *buf, size_t count) | |
2991 | { | |
2992 | u64 read_format = event->attr.read_format; | |
2993 | int ret; | |
2994 | ||
2995 | /* | |
2996 | * Return end-of-file for a read on a event that is in | |
2997 | * error state (i.e. because it was pinned but it couldn't be | |
2998 | * scheduled on to the CPU at some point). | |
2999 | */ | |
3000 | if (event->state == PERF_EVENT_STATE_ERROR) | |
3001 | return 0; | |
3002 | ||
3003 | if (count < event->read_size) | |
3004 | return -ENOSPC; | |
3005 | ||
3006 | WARN_ON_ONCE(event->ctx->parent_ctx); | |
3007 | if (read_format & PERF_FORMAT_GROUP) | |
3008 | ret = perf_event_read_group(event, read_format, buf); | |
3009 | else | |
3010 | ret = perf_event_read_one(event, read_format, buf); | |
3011 | ||
3012 | return ret; | |
3013 | } | |
3014 | ||
3015 | static ssize_t | |
3016 | perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
3017 | { | |
3018 | struct perf_event *event = file->private_data; | |
3019 | ||
3020 | return perf_read_hw(event, buf, count); | |
3021 | } | |
3022 | ||
3023 | static unsigned int perf_poll(struct file *file, poll_table *wait) | |
3024 | { | |
3025 | struct perf_event *event = file->private_data; | |
3026 | struct ring_buffer *rb; | |
3027 | unsigned int events = POLL_HUP; | |
3028 | ||
3029 | /* | |
3030 | * Race between perf_event_set_output() and perf_poll(): perf_poll() | |
3031 | * grabs the rb reference but perf_event_set_output() overrides it. | |
3032 | * Here is the timeline for two threads T1, T2: | |
3033 | * t0: T1, rb = rcu_dereference(event->rb) | |
3034 | * t1: T2, old_rb = event->rb | |
3035 | * t2: T2, event->rb = new rb | |
3036 | * t3: T2, ring_buffer_detach(old_rb) | |
3037 | * t4: T1, ring_buffer_attach(rb1) | |
3038 | * t5: T1, poll_wait(event->waitq) | |
3039 | * | |
3040 | * To avoid this problem, we grab mmap_mutex in perf_poll() | |
3041 | * thereby ensuring that the assignment of the new ring buffer | |
3042 | * and the detachment of the old buffer appear atomic to perf_poll() | |
3043 | */ | |
3044 | mutex_lock(&event->mmap_mutex); | |
3045 | ||
3046 | rcu_read_lock(); | |
3047 | rb = rcu_dereference(event->rb); | |
3048 | if (rb) { | |
3049 | ring_buffer_attach(event, rb); | |
3050 | events = atomic_xchg(&rb->poll, 0); | |
3051 | } | |
3052 | rcu_read_unlock(); | |
3053 | ||
3054 | mutex_unlock(&event->mmap_mutex); | |
3055 | ||
3056 | poll_wait(file, &event->waitq, wait); | |
3057 | ||
3058 | return events; | |
3059 | } | |
3060 | ||
3061 | static void perf_event_reset(struct perf_event *event) | |
3062 | { | |
3063 | (void)perf_event_read(event); | |
3064 | local64_set(&event->count, 0); | |
3065 | perf_event_update_userpage(event); | |
3066 | } | |
3067 | ||
3068 | /* | |
3069 | * Holding the top-level event's child_mutex means that any | |
3070 | * descendant process that has inherited this event will block | |
3071 | * in sync_child_event if it goes to exit, thus satisfying the | |
3072 | * task existence requirements of perf_event_enable/disable. | |
3073 | */ | |
3074 | static void perf_event_for_each_child(struct perf_event *event, | |
3075 | void (*func)(struct perf_event *)) | |
3076 | { | |
3077 | struct perf_event *child; | |
3078 | ||
3079 | WARN_ON_ONCE(event->ctx->parent_ctx); | |
3080 | mutex_lock(&event->child_mutex); | |
3081 | func(event); | |
3082 | list_for_each_entry(child, &event->child_list, child_list) | |
3083 | func(child); | |
3084 | mutex_unlock(&event->child_mutex); | |
3085 | } | |
3086 | ||
3087 | static void perf_event_for_each(struct perf_event *event, | |
3088 | void (*func)(struct perf_event *)) | |
3089 | { | |
3090 | struct perf_event_context *ctx = event->ctx; | |
3091 | struct perf_event *sibling; | |
3092 | ||
3093 | WARN_ON_ONCE(ctx->parent_ctx); | |
3094 | mutex_lock(&ctx->mutex); | |
3095 | event = event->group_leader; | |
3096 | ||
3097 | perf_event_for_each_child(event, func); | |
3098 | func(event); | |
3099 | list_for_each_entry(sibling, &event->sibling_list, group_entry) | |
3100 | perf_event_for_each_child(event, func); | |
3101 | mutex_unlock(&ctx->mutex); | |
3102 | } | |
3103 | ||
3104 | static int perf_event_period(struct perf_event *event, u64 __user *arg) | |
3105 | { | |
3106 | struct perf_event_context *ctx = event->ctx; | |
3107 | int ret = 0; | |
3108 | u64 value; | |
3109 | ||
3110 | if (!is_sampling_event(event)) | |
3111 | return -EINVAL; | |
3112 | ||
3113 | if (copy_from_user(&value, arg, sizeof(value))) | |
3114 | return -EFAULT; | |
3115 | ||
3116 | if (!value) | |
3117 | return -EINVAL; | |
3118 | ||
3119 | raw_spin_lock_irq(&ctx->lock); | |
3120 | if (event->attr.freq) { | |
3121 | if (value > sysctl_perf_event_sample_rate) { | |
3122 | ret = -EINVAL; | |
3123 | goto unlock; | |
3124 | } | |
3125 | ||
3126 | event->attr.sample_freq = value; | |
3127 | } else { | |
3128 | event->attr.sample_period = value; | |
3129 | event->hw.sample_period = value; | |
3130 | } | |
3131 | unlock: | |
3132 | raw_spin_unlock_irq(&ctx->lock); | |
3133 | ||
3134 | return ret; | |
3135 | } | |
3136 | ||
3137 | static const struct file_operations perf_fops; | |
3138 | ||
3139 | static struct perf_event *perf_fget_light(int fd, int *fput_needed) | |
3140 | { | |
3141 | struct file *file; | |
3142 | ||
3143 | file = fget_light(fd, fput_needed); | |
3144 | if (!file) | |
3145 | return ERR_PTR(-EBADF); | |
3146 | ||
3147 | if (file->f_op != &perf_fops) { | |
3148 | fput_light(file, *fput_needed); | |
3149 | *fput_needed = 0; | |
3150 | return ERR_PTR(-EBADF); | |
3151 | } | |
3152 | ||
3153 | return file->private_data; | |
3154 | } | |
3155 | ||
3156 | static int perf_event_set_output(struct perf_event *event, | |
3157 | struct perf_event *output_event); | |
3158 | static int perf_event_set_filter(struct perf_event *event, void __user *arg); | |
3159 | ||
3160 | static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
3161 | { | |
3162 | struct perf_event *event = file->private_data; | |
3163 | void (*func)(struct perf_event *); | |
3164 | u32 flags = arg; | |
3165 | ||
3166 | switch (cmd) { | |
3167 | case PERF_EVENT_IOC_ENABLE: | |
3168 | func = perf_event_enable; | |
3169 | break; | |
3170 | case PERF_EVENT_IOC_DISABLE: | |
3171 | func = perf_event_disable; | |
3172 | break; | |
3173 | case PERF_EVENT_IOC_RESET: | |
3174 | func = perf_event_reset; | |
3175 | break; | |
3176 | ||
3177 | case PERF_EVENT_IOC_REFRESH: | |
3178 | return perf_event_refresh(event, arg); | |
3179 | ||
3180 | case PERF_EVENT_IOC_PERIOD: | |
3181 | return perf_event_period(event, (u64 __user *)arg); | |
3182 | ||
3183 | case PERF_EVENT_IOC_SET_OUTPUT: | |
3184 | { | |
3185 | struct perf_event *output_event = NULL; | |
3186 | int fput_needed = 0; | |
3187 | int ret; | |
3188 | ||
3189 | if (arg != -1) { | |
3190 | output_event = perf_fget_light(arg, &fput_needed); | |
3191 | if (IS_ERR(output_event)) | |
3192 | return PTR_ERR(output_event); | |
3193 | } | |
3194 | ||
3195 | ret = perf_event_set_output(event, output_event); | |
3196 | if (output_event) | |
3197 | fput_light(output_event->filp, fput_needed); | |
3198 | ||
3199 | return ret; | |
3200 | } | |
3201 | ||
3202 | case PERF_EVENT_IOC_SET_FILTER: | |
3203 | return perf_event_set_filter(event, (void __user *)arg); | |
3204 | ||
3205 | default: | |
3206 | return -ENOTTY; | |
3207 | } | |
3208 | ||
3209 | if (flags & PERF_IOC_FLAG_GROUP) | |
3210 | perf_event_for_each(event, func); | |
3211 | else | |
3212 | perf_event_for_each_child(event, func); | |
3213 | ||
3214 | return 0; | |
3215 | } | |
3216 | ||
3217 | int perf_event_task_enable(void) | |
3218 | { | |
3219 | struct perf_event *event; | |
3220 | ||
3221 | mutex_lock(¤t->perf_event_mutex); | |
3222 | list_for_each_entry(event, ¤t->perf_event_list, owner_entry) | |
3223 | perf_event_for_each_child(event, perf_event_enable); | |
3224 | mutex_unlock(¤t->perf_event_mutex); | |
3225 | ||
3226 | return 0; | |
3227 | } | |
3228 | ||
3229 | int perf_event_task_disable(void) | |
3230 | { | |
3231 | struct perf_event *event; | |
3232 | ||
3233 | mutex_lock(¤t->perf_event_mutex); | |
3234 | list_for_each_entry(event, ¤t->perf_event_list, owner_entry) | |
3235 | perf_event_for_each_child(event, perf_event_disable); | |
3236 | mutex_unlock(¤t->perf_event_mutex); | |
3237 | ||
3238 | return 0; | |
3239 | } | |
3240 | ||
3241 | static int perf_event_index(struct perf_event *event) | |
3242 | { | |
3243 | if (event->hw.state & PERF_HES_STOPPED) | |
3244 | return 0; | |
3245 | ||
3246 | if (event->state != PERF_EVENT_STATE_ACTIVE) | |
3247 | return 0; | |
3248 | ||
3249 | return event->pmu->event_idx(event); | |
3250 | } | |
3251 | ||
3252 | static void calc_timer_values(struct perf_event *event, | |
3253 | u64 *now, | |
3254 | u64 *enabled, | |
3255 | u64 *running) | |
3256 | { | |
3257 | u64 ctx_time; | |
3258 | ||
3259 | *now = perf_clock(); | |
3260 | ctx_time = event->shadow_ctx_time + *now; | |
3261 | *enabled = ctx_time - event->tstamp_enabled; | |
3262 | *running = ctx_time - event->tstamp_running; | |
3263 | } | |
3264 | ||
3265 | void __weak perf_update_user_clock(struct perf_event_mmap_page *userpg, u64 now) | |
3266 | { | |
3267 | } | |
3268 | ||
3269 | /* | |
3270 | * Callers need to ensure there can be no nesting of this function, otherwise | |
3271 | * the seqlock logic goes bad. We can not serialize this because the arch | |
3272 | * code calls this from NMI context. | |
3273 | */ | |
3274 | void perf_event_update_userpage(struct perf_event *event) | |
3275 | { | |
3276 | struct perf_event_mmap_page *userpg; | |
3277 | struct ring_buffer *rb; | |
3278 | u64 enabled, running, now; | |
3279 | ||
3280 | rcu_read_lock(); | |
3281 | /* | |
3282 | * compute total_time_enabled, total_time_running | |
3283 | * based on snapshot values taken when the event | |
3284 | * was last scheduled in. | |
3285 | * | |
3286 | * we cannot simply called update_context_time() | |
3287 | * because of locking issue as we can be called in | |
3288 | * NMI context | |
3289 | */ | |
3290 | calc_timer_values(event, &now, &enabled, &running); | |
3291 | rb = rcu_dereference(event->rb); | |
3292 | if (!rb) | |
3293 | goto unlock; | |
3294 | ||
3295 | userpg = rb->user_page; | |
3296 | ||
3297 | /* | |
3298 | * Disable preemption so as to not let the corresponding user-space | |
3299 | * spin too long if we get preempted. | |
3300 | */ | |
3301 | preempt_disable(); | |
3302 | ++userpg->lock; | |
3303 | barrier(); | |
3304 | userpg->index = perf_event_index(event); | |
3305 | userpg->offset = perf_event_count(event); | |
3306 | if (userpg->index) | |
3307 | userpg->offset -= local64_read(&event->hw.prev_count); | |
3308 | ||
3309 | userpg->time_enabled = enabled + | |
3310 | atomic64_read(&event->child_total_time_enabled); | |
3311 | ||
3312 | userpg->time_running = running + | |
3313 | atomic64_read(&event->child_total_time_running); | |
3314 | ||
3315 | perf_update_user_clock(userpg, now); | |
3316 | ||
3317 | barrier(); | |
3318 | ++userpg->lock; | |
3319 | preempt_enable(); | |
3320 | unlock: | |
3321 | rcu_read_unlock(); | |
3322 | } | |
3323 | ||
3324 | static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
3325 | { | |
3326 | struct perf_event *event = vma->vm_file->private_data; | |
3327 | struct ring_buffer *rb; | |
3328 | int ret = VM_FAULT_SIGBUS; | |
3329 | ||
3330 | if (vmf->flags & FAULT_FLAG_MKWRITE) { | |
3331 | if (vmf->pgoff == 0) | |
3332 | ret = 0; | |
3333 | return ret; | |
3334 | } | |
3335 | ||
3336 | rcu_read_lock(); | |
3337 | rb = rcu_dereference(event->rb); | |
3338 | if (!rb) | |
3339 | goto unlock; | |
3340 | ||
3341 | if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) | |
3342 | goto unlock; | |
3343 | ||
3344 | vmf->page = perf_mmap_to_page(rb, vmf->pgoff); | |
3345 | if (!vmf->page) | |
3346 | goto unlock; | |
3347 | ||
3348 | get_page(vmf->page); | |
3349 | vmf->page->mapping = vma->vm_file->f_mapping; | |
3350 | vmf->page->index = vmf->pgoff; | |
3351 | ||
3352 | ret = 0; | |
3353 | unlock: | |
3354 | rcu_read_unlock(); | |
3355 | ||
3356 | return ret; | |
3357 | } | |
3358 | ||
3359 | static void ring_buffer_attach(struct perf_event *event, | |
3360 | struct ring_buffer *rb) | |
3361 | { | |
3362 | unsigned long flags; | |
3363 | ||
3364 | if (!list_empty(&event->rb_entry)) | |
3365 | return; | |
3366 | ||
3367 | spin_lock_irqsave(&rb->event_lock, flags); | |
3368 | if (!list_empty(&event->rb_entry)) | |
3369 | goto unlock; | |
3370 | ||
3371 | list_add(&event->rb_entry, &rb->event_list); | |
3372 | unlock: | |
3373 | spin_unlock_irqrestore(&rb->event_lock, flags); | |
3374 | } | |
3375 | ||
3376 | static void ring_buffer_detach(struct perf_event *event, | |
3377 | struct ring_buffer *rb) | |
3378 | { | |
3379 | unsigned long flags; | |
3380 | ||
3381 | if (list_empty(&event->rb_entry)) | |
3382 | return; | |
3383 | ||
3384 | spin_lock_irqsave(&rb->event_lock, flags); | |
3385 | list_del_init(&event->rb_entry); | |
3386 | wake_up_all(&event->waitq); | |
3387 | spin_unlock_irqrestore(&rb->event_lock, flags); | |
3388 | } | |
3389 | ||
3390 | static void ring_buffer_wakeup(struct perf_event *event) | |
3391 | { | |
3392 | struct ring_buffer *rb; | |
3393 | ||
3394 | rcu_read_lock(); | |
3395 | rb = rcu_dereference(event->rb); | |
3396 | if (!rb) | |
3397 | goto unlock; | |
3398 | ||
3399 | list_for_each_entry_rcu(event, &rb->event_list, rb_entry) | |
3400 | wake_up_all(&event->waitq); | |
3401 | ||
3402 | unlock: | |
3403 | rcu_read_unlock(); | |
3404 | } | |
3405 | ||
3406 | static void rb_free_rcu(struct rcu_head *rcu_head) | |
3407 | { | |
3408 | struct ring_buffer *rb; | |
3409 | ||
3410 | rb = container_of(rcu_head, struct ring_buffer, rcu_head); | |
3411 | rb_free(rb); | |
3412 | } | |
3413 | ||
3414 | static struct ring_buffer *ring_buffer_get(struct perf_event *event) | |
3415 | { | |
3416 | struct ring_buffer *rb; | |
3417 | ||
3418 | rcu_read_lock(); | |
3419 | rb = rcu_dereference(event->rb); | |
3420 | if (rb) { | |
3421 | if (!atomic_inc_not_zero(&rb->refcount)) | |
3422 | rb = NULL; | |
3423 | } | |
3424 | rcu_read_unlock(); | |
3425 | ||
3426 | return rb; | |
3427 | } | |
3428 | ||
3429 | static void ring_buffer_put(struct ring_buffer *rb) | |
3430 | { | |
3431 | struct perf_event *event, *n; | |
3432 | unsigned long flags; | |
3433 | ||
3434 | if (!atomic_dec_and_test(&rb->refcount)) | |
3435 | return; | |
3436 | ||
3437 | spin_lock_irqsave(&rb->event_lock, flags); | |
3438 | list_for_each_entry_safe(event, n, &rb->event_list, rb_entry) { | |
3439 | list_del_init(&event->rb_entry); | |
3440 | wake_up_all(&event->waitq); | |
3441 | } | |
3442 | spin_unlock_irqrestore(&rb->event_lock, flags); | |
3443 | ||
3444 | call_rcu(&rb->rcu_head, rb_free_rcu); | |
3445 | } | |
3446 | ||
3447 | static void perf_mmap_open(struct vm_area_struct *vma) | |
3448 | { | |
3449 | struct perf_event *event = vma->vm_file->private_data; | |
3450 | ||
3451 | atomic_inc(&event->mmap_count); | |
3452 | } | |
3453 | ||
3454 | static void perf_mmap_close(struct vm_area_struct *vma) | |
3455 | { | |
3456 | struct perf_event *event = vma->vm_file->private_data; | |
3457 | ||
3458 | if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) { | |
3459 | unsigned long size = perf_data_size(event->rb); | |
3460 | struct user_struct *user = event->mmap_user; | |
3461 | struct ring_buffer *rb = event->rb; | |
3462 | ||
3463 | atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm); | |
3464 | vma->vm_mm->pinned_vm -= event->mmap_locked; | |
3465 | rcu_assign_pointer(event->rb, NULL); | |
3466 | ring_buffer_detach(event, rb); | |
3467 | mutex_unlock(&event->mmap_mutex); | |
3468 | ||
3469 | ring_buffer_put(rb); | |
3470 | free_uid(user); | |
3471 | } | |
3472 | } | |
3473 | ||
3474 | static const struct vm_operations_struct perf_mmap_vmops = { | |
3475 | .open = perf_mmap_open, | |
3476 | .close = perf_mmap_close, | |
3477 | .fault = perf_mmap_fault, | |
3478 | .page_mkwrite = perf_mmap_fault, | |
3479 | }; | |
3480 | ||
3481 | static int perf_mmap(struct file *file, struct vm_area_struct *vma) | |
3482 | { | |
3483 | struct perf_event *event = file->private_data; | |
3484 | unsigned long user_locked, user_lock_limit; | |
3485 | struct user_struct *user = current_user(); | |
3486 | unsigned long locked, lock_limit; | |
3487 | struct ring_buffer *rb; | |
3488 | unsigned long vma_size; | |
3489 | unsigned long nr_pages; | |
3490 | long user_extra, extra; | |
3491 | int ret = 0, flags = 0; | |
3492 | ||
3493 | /* | |
3494 | * Don't allow mmap() of inherited per-task counters. This would | |
3495 | * create a performance issue due to all children writing to the | |
3496 | * same rb. | |
3497 | */ | |
3498 | if (event->cpu == -1 && event->attr.inherit) | |
3499 | return -EINVAL; | |
3500 | ||
3501 | if (!(vma->vm_flags & VM_SHARED)) | |
3502 | return -EINVAL; | |
3503 | ||
3504 | vma_size = vma->vm_end - vma->vm_start; | |
3505 | nr_pages = (vma_size / PAGE_SIZE) - 1; | |
3506 | ||
3507 | /* | |
3508 | * If we have rb pages ensure they're a power-of-two number, so we | |
3509 | * can do bitmasks instead of modulo. | |
3510 | */ | |
3511 | if (nr_pages != 0 && !is_power_of_2(nr_pages)) | |
3512 | return -EINVAL; | |
3513 | ||
3514 | if (vma_size != PAGE_SIZE * (1 + nr_pages)) | |
3515 | return -EINVAL; | |
3516 | ||
3517 | if (vma->vm_pgoff != 0) | |
3518 | return -EINVAL; | |
3519 | ||
3520 | WARN_ON_ONCE(event->ctx->parent_ctx); | |
3521 | mutex_lock(&event->mmap_mutex); | |
3522 | if (event->rb) { | |
3523 | if (event->rb->nr_pages == nr_pages) | |
3524 | atomic_inc(&event->rb->refcount); | |
3525 | else | |
3526 | ret = -EINVAL; | |
3527 | goto unlock; | |
3528 | } | |
3529 | ||
3530 | user_extra = nr_pages + 1; | |
3531 | user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); | |
3532 | ||
3533 | /* | |
3534 | * Increase the limit linearly with more CPUs: | |
3535 | */ | |
3536 | user_lock_limit *= num_online_cpus(); | |
3537 | ||
3538 | user_locked = atomic_long_read(&user->locked_vm) + user_extra; | |
3539 | ||
3540 | extra = 0; | |
3541 | if (user_locked > user_lock_limit) | |
3542 | extra = user_locked - user_lock_limit; | |
3543 | ||
3544 | lock_limit = rlimit(RLIMIT_MEMLOCK); | |
3545 | lock_limit >>= PAGE_SHIFT; | |
3546 | locked = vma->vm_mm->pinned_vm + extra; | |
3547 | ||
3548 | if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && | |
3549 | !capable(CAP_IPC_LOCK)) { | |
3550 | ret = -EPERM; | |
3551 | goto unlock; | |
3552 | } | |
3553 | ||
3554 | WARN_ON(event->rb); | |
3555 | ||
3556 | if (vma->vm_flags & VM_WRITE) | |
3557 | flags |= RING_BUFFER_WRITABLE; | |
3558 | ||
3559 | rb = rb_alloc(nr_pages, | |
3560 | event->attr.watermark ? event->attr.wakeup_watermark : 0, | |
3561 | event->cpu, flags); | |
3562 | ||
3563 | if (!rb) { | |
3564 | ret = -ENOMEM; | |
3565 | goto unlock; | |
3566 | } | |
3567 | rcu_assign_pointer(event->rb, rb); | |
3568 | ||
3569 | atomic_long_add(user_extra, &user->locked_vm); | |
3570 | event->mmap_locked = extra; | |
3571 | event->mmap_user = get_current_user(); | |
3572 | vma->vm_mm->pinned_vm += event->mmap_locked; | |
3573 | ||
3574 | perf_event_update_userpage(event); | |
3575 | ||
3576 | unlock: | |
3577 | if (!ret) | |
3578 | atomic_inc(&event->mmap_count); | |
3579 | mutex_unlock(&event->mmap_mutex); | |
3580 | ||
3581 | vma->vm_flags |= VM_RESERVED; | |
3582 | vma->vm_ops = &perf_mmap_vmops; | |
3583 | ||
3584 | return ret; | |
3585 | } | |
3586 | ||
3587 | static int perf_fasync(int fd, struct file *filp, int on) | |
3588 | { | |
3589 | struct inode *inode = filp->f_path.dentry->d_inode; | |
3590 | struct perf_event *event = filp->private_data; | |
3591 | int retval; | |
3592 | ||
3593 | mutex_lock(&inode->i_mutex); | |
3594 | retval = fasync_helper(fd, filp, on, &event->fasync); | |
3595 | mutex_unlock(&inode->i_mutex); | |
3596 | ||
3597 | if (retval < 0) | |
3598 | return retval; | |
3599 | ||
3600 | return 0; | |
3601 | } | |
3602 | ||
3603 | static const struct file_operations perf_fops = { | |
3604 | .llseek = no_llseek, | |
3605 | .release = perf_release, | |
3606 | .read = perf_read, | |
3607 | .poll = perf_poll, | |
3608 | .unlocked_ioctl = perf_ioctl, | |
3609 | .compat_ioctl = perf_ioctl, | |
3610 | .mmap = perf_mmap, | |
3611 | .fasync = perf_fasync, | |
3612 | }; | |
3613 | ||
3614 | /* | |
3615 | * Perf event wakeup | |
3616 | * | |
3617 | * If there's data, ensure we set the poll() state and publish everything | |
3618 | * to user-space before waking everybody up. | |
3619 | */ | |
3620 | ||
3621 | void perf_event_wakeup(struct perf_event *event) | |
3622 | { | |
3623 | ring_buffer_wakeup(event); | |
3624 | ||
3625 | if (event->pending_kill) { | |
3626 | kill_fasync(&event->fasync, SIGIO, event->pending_kill); | |
3627 | event->pending_kill = 0; | |
3628 | } | |
3629 | } | |
3630 | ||
3631 | static void perf_pending_event(struct irq_work *entry) | |
3632 | { | |
3633 | struct perf_event *event = container_of(entry, | |
3634 | struct perf_event, pending); | |
3635 | ||
3636 | if (event->pending_disable) { | |
3637 | event->pending_disable = 0; | |
3638 | __perf_event_disable(event); | |
3639 | } | |
3640 | ||
3641 | if (event->pending_wakeup) { | |
3642 | event->pending_wakeup = 0; | |
3643 | perf_event_wakeup(event); | |
3644 | } | |
3645 | } | |
3646 | ||
3647 | /* | |
3648 | * We assume there is only KVM supporting the callbacks. | |
3649 | * Later on, we might change it to a list if there is | |
3650 | * another virtualization implementation supporting the callbacks. | |
3651 | */ | |
3652 | struct perf_guest_info_callbacks *perf_guest_cbs; | |
3653 | ||
3654 | int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) | |
3655 | { | |
3656 | perf_guest_cbs = cbs; | |
3657 | return 0; | |
3658 | } | |
3659 | EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); | |
3660 | ||
3661 | int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) | |
3662 | { | |
3663 | perf_guest_cbs = NULL; | |
3664 | return 0; | |
3665 | } | |
3666 | EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); | |
3667 | ||
3668 | static void __perf_event_header__init_id(struct perf_event_header *header, | |
3669 | struct perf_sample_data *data, | |
3670 | struct perf_event *event) | |
3671 | { | |
3672 | u64 sample_type = event->attr.sample_type; | |
3673 | ||
3674 | data->type = sample_type; | |
3675 | header->size += event->id_header_size; | |
3676 | ||
3677 | if (sample_type & PERF_SAMPLE_TID) { | |
3678 | /* namespace issues */ | |
3679 | data->tid_entry.pid = perf_event_pid(event, current); | |
3680 | data->tid_entry.tid = perf_event_tid(event, current); | |
3681 | } | |
3682 | ||
3683 | if (sample_type & PERF_SAMPLE_TIME) | |
3684 | data->time = perf_clock(); | |
3685 | ||
3686 | if (sample_type & PERF_SAMPLE_ID) | |
3687 | data->id = primary_event_id(event); | |
3688 | ||
3689 | if (sample_type & PERF_SAMPLE_STREAM_ID) | |
3690 | data->stream_id = event->id; | |
3691 | ||
3692 | if (sample_type & PERF_SAMPLE_CPU) { | |
3693 | data->cpu_entry.cpu = raw_smp_processor_id(); | |
3694 | data->cpu_entry.reserved = 0; | |
3695 | } | |
3696 | } | |
3697 | ||
3698 | void perf_event_header__init_id(struct perf_event_header *header, | |
3699 | struct perf_sample_data *data, | |
3700 | struct perf_event *event) | |
3701 | { | |
3702 | if (event->attr.sample_id_all) | |
3703 | __perf_event_header__init_id(header, data, event); | |
3704 | } | |
3705 | ||
3706 | static void __perf_event__output_id_sample(struct perf_output_handle *handle, | |
3707 | struct perf_sample_data *data) | |
3708 | { | |
3709 | u64 sample_type = data->type; | |
3710 | ||
3711 | if (sample_type & PERF_SAMPLE_TID) | |
3712 | perf_output_put(handle, data->tid_entry); | |
3713 | ||
3714 | if (sample_type & PERF_SAMPLE_TIME) | |
3715 | perf_output_put(handle, data->time); | |
3716 | ||
3717 | if (sample_type & PERF_SAMPLE_ID) | |
3718 | perf_output_put(handle, data->id); | |
3719 | ||
3720 | if (sample_type & PERF_SAMPLE_STREAM_ID) | |
3721 | perf_output_put(handle, data->stream_id); | |
3722 | ||
3723 | if (sample_type & PERF_SAMPLE_CPU) | |
3724 | perf_output_put(handle, data->cpu_entry); | |
3725 | } | |
3726 | ||
3727 | void perf_event__output_id_sample(struct perf_event *event, | |
3728 | struct perf_output_handle *handle, | |
3729 | struct perf_sample_data *sample) | |
3730 | { | |
3731 | if (event->attr.sample_id_all) | |
3732 | __perf_event__output_id_sample(handle, sample); | |
3733 | } | |
3734 | ||
3735 | static void perf_output_read_one(struct perf_output_handle *handle, | |
3736 | struct perf_event *event, | |
3737 | u64 enabled, u64 running) | |
3738 | { | |
3739 | u64 read_format = event->attr.read_format; | |
3740 | u64 values[4]; | |
3741 | int n = 0; | |
3742 | ||
3743 | values[n++] = perf_event_count(event); | |
3744 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { | |
3745 | values[n++] = enabled + | |
3746 | atomic64_read(&event->child_total_time_enabled); | |
3747 | } | |
3748 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { | |
3749 | values[n++] = running + | |
3750 | atomic64_read(&event->child_total_time_running); | |
3751 | } | |
3752 | if (read_format & PERF_FORMAT_ID) | |
3753 | values[n++] = primary_event_id(event); | |
3754 | ||
3755 | __output_copy(handle, values, n * sizeof(u64)); | |
3756 | } | |
3757 | ||
3758 | /* | |
3759 | * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. | |
3760 | */ | |
3761 | static void perf_output_read_group(struct perf_output_handle *handle, | |
3762 | struct perf_event *event, | |
3763 | u64 enabled, u64 running) | |
3764 | { | |
3765 | struct perf_event *leader = event->group_leader, *sub; | |
3766 | u64 read_format = event->attr.read_format; | |
3767 | u64 values[5]; | |
3768 | int n = 0; | |
3769 | ||
3770 | values[n++] = 1 + leader->nr_siblings; | |
3771 | ||
3772 | if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) | |
3773 | values[n++] = enabled; | |
3774 | ||
3775 | if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) | |
3776 | values[n++] = running; | |
3777 | ||
3778 | if (leader != event) | |
3779 | leader->pmu->read(leader); | |
3780 | ||
3781 | values[n++] = perf_event_count(leader); | |
3782 | if (read_format & PERF_FORMAT_ID) | |
3783 | values[n++] = primary_event_id(leader); | |
3784 | ||
3785 | __output_copy(handle, values, n * sizeof(u64)); | |
3786 | ||
3787 | list_for_each_entry(sub, &leader->sibling_list, group_entry) { | |
3788 | n = 0; | |
3789 | ||
3790 | if (sub != event) | |
3791 | sub->pmu->read(sub); | |
3792 | ||
3793 | values[n++] = perf_event_count(sub); | |
3794 | if (read_format & PERF_FORMAT_ID) | |
3795 | values[n++] = primary_event_id(sub); | |
3796 | ||
3797 | __output_copy(handle, values, n * sizeof(u64)); | |
3798 | } | |
3799 | } | |
3800 | ||
3801 | #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ | |
3802 | PERF_FORMAT_TOTAL_TIME_RUNNING) | |
3803 | ||
3804 | static void perf_output_read(struct perf_output_handle *handle, | |
3805 | struct perf_event *event) | |
3806 | { | |
3807 | u64 enabled = 0, running = 0, now; | |
3808 | u64 read_format = event->attr.read_format; | |
3809 | ||
3810 | /* | |
3811 | * compute total_time_enabled, total_time_running | |
3812 | * based on snapshot values taken when the event | |
3813 | * was last scheduled in. | |
3814 | * | |
3815 | * we cannot simply called update_context_time() | |
3816 | * because of locking issue as we are called in | |
3817 | * NMI context | |
3818 | */ | |
3819 | if (read_format & PERF_FORMAT_TOTAL_TIMES) | |
3820 | calc_timer_values(event, &now, &enabled, &running); | |
3821 | ||
3822 | if (event->attr.read_format & PERF_FORMAT_GROUP) | |
3823 | perf_output_read_group(handle, event, enabled, running); | |
3824 | else | |
3825 | perf_output_read_one(handle, event, enabled, running); | |
3826 | } | |
3827 | ||
3828 | void perf_output_sample(struct perf_output_handle *handle, | |
3829 | struct perf_event_header *header, | |
3830 | struct perf_sample_data *data, | |
3831 | struct perf_event *event) | |
3832 | { | |
3833 | u64 sample_type = data->type; | |
3834 | ||
3835 | perf_output_put(handle, *header); | |
3836 | ||
3837 | if (sample_type & PERF_SAMPLE_IP) | |
3838 | perf_output_put(handle, data->ip); | |
3839 | ||
3840 | if (sample_type & PERF_SAMPLE_TID) | |
3841 | perf_output_put(handle, data->tid_entry); | |
3842 | ||
3843 | if (sample_type & PERF_SAMPLE_TIME) | |
3844 | perf_output_put(handle, data->time); | |
3845 | ||
3846 | if (sample_type & PERF_SAMPLE_ADDR) | |
3847 | perf_output_put(handle, data->addr); | |
3848 | ||
3849 | if (sample_type & PERF_SAMPLE_ID) | |
3850 | perf_output_put(handle, data->id); | |
3851 | ||
3852 | if (sample_type & PERF_SAMPLE_STREAM_ID) | |
3853 | perf_output_put(handle, data->stream_id); | |
3854 | ||
3855 | if (sample_type & PERF_SAMPLE_CPU) | |
3856 | perf_output_put(handle, data->cpu_entry); | |
3857 | ||
3858 | if (sample_type & PERF_SAMPLE_PERIOD) | |
3859 | perf_output_put(handle, data->period); | |
3860 | ||
3861 | if (sample_type & PERF_SAMPLE_READ) | |
3862 | perf_output_read(handle, event); | |
3863 | ||
3864 | if (sample_type & PERF_SAMPLE_CALLCHAIN) { | |
3865 | if (data->callchain) { | |
3866 | int size = 1; | |
3867 | ||
3868 | if (data->callchain) | |
3869 | size += data->callchain->nr; | |
3870 | ||
3871 | size *= sizeof(u64); | |
3872 | ||
3873 | __output_copy(handle, data->callchain, size); | |
3874 | } else { | |
3875 | u64 nr = 0; | |
3876 | perf_output_put(handle, nr); | |
3877 | } | |
3878 | } | |
3879 | ||
3880 | if (sample_type & PERF_SAMPLE_RAW) { | |
3881 | if (data->raw) { | |
3882 | perf_output_put(handle, data->raw->size); | |
3883 | __output_copy(handle, data->raw->data, | |
3884 | data->raw->size); | |
3885 | } else { | |
3886 | struct { | |
3887 | u32 size; | |
3888 | u32 data; | |
3889 | } raw = { | |
3890 | .size = sizeof(u32), | |
3891 | .data = 0, | |
3892 | }; | |
3893 | perf_output_put(handle, raw); | |
3894 | } | |
3895 | } | |
3896 | ||
3897 | if (!event->attr.watermark) { | |
3898 | int wakeup_events = event->attr.wakeup_events; | |
3899 | ||
3900 | if (wakeup_events) { | |
3901 | struct ring_buffer *rb = handle->rb; | |
3902 | int events = local_inc_return(&rb->events); | |
3903 | ||
3904 | if (events >= wakeup_events) { | |
3905 | local_sub(wakeup_events, &rb->events); | |
3906 | local_inc(&rb->wakeup); | |
3907 | } | |
3908 | } | |
3909 | } | |
3910 | } | |
3911 | ||
3912 | void perf_prepare_sample(struct perf_event_header *header, | |
3913 | struct perf_sample_data *data, | |
3914 | struct perf_event *event, | |
3915 | struct pt_regs *regs) | |
3916 | { | |
3917 | u64 sample_type = event->attr.sample_type; | |
3918 | ||
3919 | header->type = PERF_RECORD_SAMPLE; | |
3920 | header->size = sizeof(*header) + event->header_size; | |
3921 | ||
3922 | header->misc = 0; | |
3923 | header->misc |= perf_misc_flags(regs); | |
3924 | ||
3925 | __perf_event_header__init_id(header, data, event); | |
3926 | ||
3927 | if (sample_type & PERF_SAMPLE_IP) | |
3928 | data->ip = perf_instruction_pointer(regs); | |
3929 | ||
3930 | if (sample_type & PERF_SAMPLE_CALLCHAIN) { | |
3931 | int size = 1; | |
3932 | ||
3933 | data->callchain = perf_callchain(regs); | |
3934 | ||
3935 | if (data->callchain) | |
3936 | size += data->callchain->nr; | |
3937 | ||
3938 | header->size += size * sizeof(u64); | |
3939 | } | |
3940 | ||
3941 | if (sample_type & PERF_SAMPLE_RAW) { | |
3942 | int size = sizeof(u32); | |
3943 | ||
3944 | if (data->raw) | |
3945 | size += data->raw->size; | |
3946 | else | |
3947 | size += sizeof(u32); | |
3948 | ||
3949 | WARN_ON_ONCE(size & (sizeof(u64)-1)); | |
3950 | header->size += size; | |
3951 | } | |
3952 | } | |
3953 | ||
3954 | static void perf_event_output(struct perf_event *event, | |
3955 | struct perf_sample_data *data, | |
3956 | struct pt_regs *regs) | |
3957 | { | |
3958 | struct perf_output_handle handle; | |
3959 | struct perf_event_header header; | |
3960 | ||
3961 | /* protect the callchain buffers */ | |
3962 | rcu_read_lock(); | |
3963 | ||
3964 | perf_prepare_sample(&header, data, event, regs); | |
3965 | ||
3966 | if (perf_output_begin(&handle, event, header.size)) | |
3967 | goto exit; | |
3968 | ||
3969 | perf_output_sample(&handle, &header, data, event); | |
3970 | ||
3971 | perf_output_end(&handle); | |
3972 | ||
3973 | exit: | |
3974 | rcu_read_unlock(); | |
3975 | } | |
3976 | ||
3977 | /* | |
3978 | * read event_id | |
3979 | */ | |
3980 | ||
3981 | struct perf_read_event { | |
3982 | struct perf_event_header header; | |
3983 | ||
3984 | u32 pid; | |
3985 | u32 tid; | |
3986 | }; | |
3987 | ||
3988 | static void | |
3989 | perf_event_read_event(struct perf_event *event, | |
3990 | struct task_struct *task) | |
3991 | { | |
3992 | struct perf_output_handle handle; | |
3993 | struct perf_sample_data sample; | |
3994 | struct perf_read_event read_event = { | |
3995 | .header = { | |
3996 | .type = PERF_RECORD_READ, | |
3997 | .misc = 0, | |
3998 | .size = sizeof(read_event) + event->read_size, | |
3999 | }, | |
4000 | .pid = perf_event_pid(event, task), | |
4001 | .tid = perf_event_tid(event, task), | |
4002 | }; | |
4003 | int ret; | |
4004 | ||
4005 | perf_event_header__init_id(&read_event.header, &sample, event); | |
4006 | ret = perf_output_begin(&handle, event, read_event.header.size); | |
4007 | if (ret) | |
4008 | return; | |
4009 | ||
4010 | perf_output_put(&handle, read_event); | |
4011 | perf_output_read(&handle, event); | |
4012 | perf_event__output_id_sample(event, &handle, &sample); | |
4013 | ||
4014 | perf_output_end(&handle); | |
4015 | } | |
4016 | ||
4017 | /* | |
4018 | * task tracking -- fork/exit | |
4019 | * | |
4020 | * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task | |
4021 | */ | |
4022 | ||
4023 | struct perf_task_event { | |
4024 | struct task_struct *task; | |
4025 | struct perf_event_context *task_ctx; | |
4026 | ||
4027 | struct { | |
4028 | struct perf_event_header header; | |
4029 | ||
4030 | u32 pid; | |
4031 | u32 ppid; | |
4032 | u32 tid; | |
4033 | u32 ptid; | |
4034 | u64 time; | |
4035 | } event_id; | |
4036 | }; | |
4037 | ||
4038 | static void perf_event_task_output(struct perf_event *event, | |
4039 | struct perf_task_event *task_event) | |
4040 | { | |
4041 | struct perf_output_handle handle; | |
4042 | struct perf_sample_data sample; | |
4043 | struct task_struct *task = task_event->task; | |
4044 | int ret, size = task_event->event_id.header.size; | |
4045 | ||
4046 | perf_event_header__init_id(&task_event->event_id.header, &sample, event); | |
4047 | ||
4048 | ret = perf_output_begin(&handle, event, | |
4049 | task_event->event_id.header.size); | |
4050 | if (ret) | |
4051 | goto out; | |
4052 | ||
4053 | task_event->event_id.pid = perf_event_pid(event, task); | |
4054 | task_event->event_id.ppid = perf_event_pid(event, current); | |
4055 | ||
4056 | task_event->event_id.tid = perf_event_tid(event, task); | |
4057 | task_event->event_id.ptid = perf_event_tid(event, current); | |
4058 | ||
4059 | perf_output_put(&handle, task_event->event_id); | |
4060 | ||
4061 | perf_event__output_id_sample(event, &handle, &sample); | |
4062 | ||
4063 | perf_output_end(&handle); | |
4064 | out: | |
4065 | task_event->event_id.header.size = size; | |
4066 | } | |
4067 | ||
4068 | static int perf_event_task_match(struct perf_event *event) | |
4069 | { | |
4070 | if (event->state < PERF_EVENT_STATE_INACTIVE) | |
4071 | return 0; | |
4072 | ||
4073 | if (!event_filter_match(event)) | |
4074 | return 0; | |
4075 | ||
4076 | if (event->attr.comm || event->attr.mmap || | |
4077 | event->attr.mmap_data || event->attr.task) | |
4078 | return 1; | |
4079 | ||
4080 | return 0; | |
4081 | } | |
4082 | ||
4083 | static void perf_event_task_ctx(struct perf_event_context *ctx, | |
4084 | struct perf_task_event *task_event) | |
4085 | { | |
4086 | struct perf_event *event; | |
4087 | ||
4088 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { | |
4089 | if (perf_event_task_match(event)) | |
4090 | perf_event_task_output(event, task_event); | |
4091 | } | |
4092 | } | |
4093 | ||
4094 | static void perf_event_task_event(struct perf_task_event *task_event) | |
4095 | { | |
4096 | struct perf_cpu_context *cpuctx; | |
4097 | struct perf_event_context *ctx; | |
4098 | struct pmu *pmu; | |
4099 | int ctxn; | |
4100 | ||
4101 | rcu_read_lock(); | |
4102 | list_for_each_entry_rcu(pmu, &pmus, entry) { | |
4103 | cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); | |
4104 | if (cpuctx->active_pmu != pmu) | |
4105 | goto next; | |
4106 | perf_event_task_ctx(&cpuctx->ctx, task_event); | |
4107 | ||
4108 | ctx = task_event->task_ctx; | |
4109 | if (!ctx) { | |
4110 | ctxn = pmu->task_ctx_nr; | |
4111 | if (ctxn < 0) | |
4112 | goto next; | |
4113 | ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); | |
4114 | } | |
4115 | if (ctx) | |
4116 | perf_event_task_ctx(ctx, task_event); | |
4117 | next: | |
4118 | put_cpu_ptr(pmu->pmu_cpu_context); | |
4119 | } | |
4120 | rcu_read_unlock(); | |
4121 | } | |
4122 | ||
4123 | static void perf_event_task(struct task_struct *task, | |
4124 | struct perf_event_context *task_ctx, | |
4125 | int new) | |
4126 | { | |
4127 | struct perf_task_event task_event; | |
4128 | ||
4129 | if (!atomic_read(&nr_comm_events) && | |
4130 | !atomic_read(&nr_mmap_events) && | |
4131 | !atomic_read(&nr_task_events)) | |
4132 | return; | |
4133 | ||
4134 | task_event = (struct perf_task_event){ | |
4135 | .task = task, | |
4136 | .task_ctx = task_ctx, | |
4137 | .event_id = { | |
4138 | .header = { | |
4139 | .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, | |
4140 | .misc = 0, | |
4141 | .size = sizeof(task_event.event_id), | |
4142 | }, | |
4143 | /* .pid */ | |
4144 | /* .ppid */ | |
4145 | /* .tid */ | |
4146 | /* .ptid */ | |
4147 | .time = perf_clock(), | |
4148 | }, | |
4149 | }; | |
4150 | ||
4151 | perf_event_task_event(&task_event); | |
4152 | } | |
4153 | ||
4154 | void perf_event_fork(struct task_struct *task) | |
4155 | { | |
4156 | perf_event_task(task, NULL, 1); | |
4157 | } | |
4158 | ||
4159 | /* | |
4160 | * comm tracking | |
4161 | */ | |
4162 | ||
4163 | struct perf_comm_event { | |
4164 | struct task_struct *task; | |
4165 | char *comm; | |
4166 | int comm_size; | |
4167 | ||
4168 | struct { | |
4169 | struct perf_event_header header; | |
4170 | ||
4171 | u32 pid; | |
4172 | u32 tid; | |
4173 | } event_id; | |
4174 | }; | |
4175 | ||
4176 | static void perf_event_comm_output(struct perf_event *event, | |
4177 | struct perf_comm_event *comm_event) | |
4178 | { | |
4179 | struct perf_output_handle handle; | |
4180 | struct perf_sample_data sample; | |
4181 | int size = comm_event->event_id.header.size; | |
4182 | int ret; | |
4183 | ||
4184 | perf_event_header__init_id(&comm_event->event_id.header, &sample, event); | |
4185 | ret = perf_output_begin(&handle, event, | |
4186 | comm_event->event_id.header.size); | |
4187 | ||
4188 | if (ret) | |
4189 | goto out; | |
4190 | ||
4191 | comm_event->event_id.pid = perf_event_pid(event, comm_event->task); | |
4192 | comm_event->event_id.tid = perf_event_tid(event, comm_event->task); | |
4193 | ||
4194 | perf_output_put(&handle, comm_event->event_id); | |
4195 | __output_copy(&handle, comm_event->comm, | |
4196 | comm_event->comm_size); | |
4197 | ||
4198 | perf_event__output_id_sample(event, &handle, &sample); | |
4199 | ||
4200 | perf_output_end(&handle); | |
4201 | out: | |
4202 | comm_event->event_id.header.size = size; | |
4203 | } | |
4204 | ||
4205 | static int perf_event_comm_match(struct perf_event *event) | |
4206 | { | |
4207 | if (event->state < PERF_EVENT_STATE_INACTIVE) | |
4208 | return 0; | |
4209 | ||
4210 | if (!event_filter_match(event)) | |
4211 | return 0; | |
4212 | ||
4213 | if (event->attr.comm) | |
4214 | return 1; | |
4215 | ||
4216 | return 0; | |
4217 | } | |
4218 | ||
4219 | static void perf_event_comm_ctx(struct perf_event_context *ctx, | |
4220 | struct perf_comm_event *comm_event) | |
4221 | { | |
4222 | struct perf_event *event; | |
4223 | ||
4224 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { | |
4225 | if (perf_event_comm_match(event)) | |
4226 | perf_event_comm_output(event, comm_event); | |
4227 | } | |
4228 | } | |
4229 | ||
4230 | static void perf_event_comm_event(struct perf_comm_event *comm_event) | |
4231 | { | |
4232 | struct perf_cpu_context *cpuctx; | |
4233 | struct perf_event_context *ctx; | |
4234 | char comm[TASK_COMM_LEN]; | |
4235 | unsigned int size; | |
4236 | struct pmu *pmu; | |
4237 | int ctxn; | |
4238 | ||
4239 | memset(comm, 0, sizeof(comm)); | |
4240 | strlcpy(comm, comm_event->task->comm, sizeof(comm)); | |
4241 | size = ALIGN(strlen(comm)+1, sizeof(u64)); | |
4242 | ||
4243 | comm_event->comm = comm; | |
4244 | comm_event->comm_size = size; | |
4245 | ||
4246 | comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; | |
4247 | rcu_read_lock(); | |
4248 | list_for_each_entry_rcu(pmu, &pmus, entry) { | |
4249 | cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); | |
4250 | if (cpuctx->active_pmu != pmu) | |
4251 | goto next; | |
4252 | perf_event_comm_ctx(&cpuctx->ctx, comm_event); | |
4253 | ||
4254 | ctxn = pmu->task_ctx_nr; | |
4255 | if (ctxn < 0) | |
4256 | goto next; | |
4257 | ||
4258 | ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); | |
4259 | if (ctx) | |
4260 | perf_event_comm_ctx(ctx, comm_event); | |
4261 | next: | |
4262 | put_cpu_ptr(pmu->pmu_cpu_context); | |
4263 | } | |
4264 | rcu_read_unlock(); | |
4265 | } | |
4266 | ||
4267 | void perf_event_comm(struct task_struct *task) | |
4268 | { | |
4269 | struct perf_comm_event comm_event; | |
4270 | struct perf_event_context *ctx; | |
4271 | int ctxn; | |
4272 | ||
4273 | for_each_task_context_nr(ctxn) { | |
4274 | ctx = task->perf_event_ctxp[ctxn]; | |
4275 | if (!ctx) | |
4276 | continue; | |
4277 | ||
4278 | perf_event_enable_on_exec(ctx); | |
4279 | } | |
4280 | ||
4281 | if (!atomic_read(&nr_comm_events)) | |
4282 | return; | |
4283 | ||
4284 | comm_event = (struct perf_comm_event){ | |
4285 | .task = task, | |
4286 | /* .comm */ | |
4287 | /* .comm_size */ | |
4288 | .event_id = { | |
4289 | .header = { | |
4290 | .type = PERF_RECORD_COMM, | |
4291 | .misc = 0, | |
4292 | /* .size */ | |
4293 | }, | |
4294 | /* .pid */ | |
4295 | /* .tid */ | |
4296 | }, | |
4297 | }; | |
4298 | ||
4299 | perf_event_comm_event(&comm_event); | |
4300 | } | |
4301 | ||
4302 | /* | |
4303 | * mmap tracking | |
4304 | */ | |
4305 | ||
4306 | struct perf_mmap_event { | |
4307 | struct vm_area_struct *vma; | |
4308 | ||
4309 | const char *file_name; | |
4310 | int file_size; | |
4311 | ||
4312 | struct { | |
4313 | struct perf_event_header header; | |
4314 | ||
4315 | u32 pid; | |
4316 | u32 tid; | |
4317 | u64 start; | |
4318 | u64 len; | |
4319 | u64 pgoff; | |
4320 | } event_id; | |
4321 | }; | |
4322 | ||
4323 | static void perf_event_mmap_output(struct perf_event *event, | |
4324 | struct perf_mmap_event *mmap_event) | |
4325 | { | |
4326 | struct perf_output_handle handle; | |
4327 | struct perf_sample_data sample; | |
4328 | int size = mmap_event->event_id.header.size; | |
4329 | int ret; | |
4330 | ||
4331 | perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); | |
4332 | ret = perf_output_begin(&handle, event, | |
4333 | mmap_event->event_id.header.size); | |
4334 | if (ret) | |
4335 | goto out; | |
4336 | ||
4337 | mmap_event->event_id.pid = perf_event_pid(event, current); | |
4338 | mmap_event->event_id.tid = perf_event_tid(event, current); | |
4339 | ||
4340 | perf_output_put(&handle, mmap_event->event_id); | |
4341 | __output_copy(&handle, mmap_event->file_name, | |
4342 | mmap_event->file_size); | |
4343 | ||
4344 | perf_event__output_id_sample(event, &handle, &sample); | |
4345 | ||
4346 | perf_output_end(&handle); | |
4347 | out: | |
4348 | mmap_event->event_id.header.size = size; | |
4349 | } | |
4350 | ||
4351 | static int perf_event_mmap_match(struct perf_event *event, | |
4352 | struct perf_mmap_event *mmap_event, | |
4353 | int executable) | |
4354 | { | |
4355 | if (event->state < PERF_EVENT_STATE_INACTIVE) | |
4356 | return 0; | |
4357 | ||
4358 | if (!event_filter_match(event)) | |
4359 | return 0; | |
4360 | ||
4361 | if ((!executable && event->attr.mmap_data) || | |
4362 | (executable && event->attr.mmap)) | |
4363 | return 1; | |
4364 | ||
4365 | return 0; | |
4366 | } | |
4367 | ||
4368 | static void perf_event_mmap_ctx(struct perf_event_context *ctx, | |
4369 | struct perf_mmap_event *mmap_event, | |
4370 | int executable) | |
4371 | { | |
4372 | struct perf_event *event; | |
4373 | ||
4374 | list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { | |
4375 | if (perf_event_mmap_match(event, mmap_event, executable)) | |
4376 | perf_event_mmap_output(event, mmap_event); | |
4377 | } | |
4378 | } | |
4379 | ||
4380 | static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) | |
4381 | { | |
4382 | struct perf_cpu_context *cpuctx; | |
4383 | struct perf_event_context *ctx; | |
4384 | struct vm_area_struct *vma = mmap_event->vma; | |
4385 | struct file *file = vma->vm_file; | |
4386 | unsigned int size; | |
4387 | char tmp[16]; | |
4388 | char *buf = NULL; | |
4389 | const char *name; | |
4390 | struct pmu *pmu; | |
4391 | int ctxn; | |
4392 | ||
4393 | memset(tmp, 0, sizeof(tmp)); | |
4394 | ||
4395 | if (file) { | |
4396 | /* | |
4397 | * d_path works from the end of the rb backwards, so we | |
4398 | * need to add enough zero bytes after the string to handle | |
4399 | * the 64bit alignment we do later. | |
4400 | */ | |
4401 | buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL); | |
4402 | if (!buf) { | |
4403 | name = strncpy(tmp, "//enomem", sizeof(tmp)); | |
4404 | goto got_name; | |
4405 | } | |
4406 | name = d_path(&file->f_path, buf, PATH_MAX); | |
4407 | if (IS_ERR(name)) { | |
4408 | name = strncpy(tmp, "//toolong", sizeof(tmp)); | |
4409 | goto got_name; | |
4410 | } | |
4411 | } else { | |
4412 | if (arch_vma_name(mmap_event->vma)) { | |
4413 | name = strncpy(tmp, arch_vma_name(mmap_event->vma), | |
4414 | sizeof(tmp)); | |
4415 | goto got_name; | |
4416 | } | |
4417 | ||
4418 | if (!vma->vm_mm) { | |
4419 | name = strncpy(tmp, "[vdso]", sizeof(tmp)); | |
4420 | goto got_name; | |
4421 | } else if (vma->vm_start <= vma->vm_mm->start_brk && | |
4422 | vma->vm_end >= vma->vm_mm->brk) { | |
4423 | name = strncpy(tmp, "[heap]", sizeof(tmp)); | |
4424 | goto got_name; | |
4425 | } else if (vma->vm_start <= vma->vm_mm->start_stack && | |
4426 | vma->vm_end >= vma->vm_mm->start_stack) { | |
4427 | name = strncpy(tmp, "[stack]", sizeof(tmp)); | |
4428 | goto got_name; | |
4429 | } | |
4430 | ||
4431 | name = strncpy(tmp, "//anon", sizeof(tmp)); | |
4432 | goto got_name; | |
4433 | } | |
4434 | ||
4435 | got_name: | |
4436 | size = ALIGN(strlen(name)+1, sizeof(u64)); | |
4437 | ||
4438 | mmap_event->file_name = name; | |
4439 | mmap_event->file_size = size; | |
4440 | ||
4441 | mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; | |
4442 | ||
4443 | rcu_read_lock(); | |
4444 | list_for_each_entry_rcu(pmu, &pmus, entry) { | |
4445 | cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); | |
4446 | if (cpuctx->active_pmu != pmu) | |
4447 | goto next; | |
4448 | perf_event_mmap_ctx(&cpuctx->ctx, mmap_event, | |
4449 | vma->vm_flags & VM_EXEC); | |
4450 | ||
4451 | ctxn = pmu->task_ctx_nr; | |
4452 | if (ctxn < 0) | |
4453 | goto next; | |
4454 | ||
4455 | ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); | |
4456 | if (ctx) { | |
4457 | perf_event_mmap_ctx(ctx, mmap_event, | |
4458 | vma->vm_flags & VM_EXEC); | |
4459 | } | |
4460 | next: | |
4461 | put_cpu_ptr(pmu->pmu_cpu_context); | |
4462 | } | |
4463 | rcu_read_unlock(); | |
4464 | ||
4465 | kfree(buf); | |
4466 | } | |
4467 | ||
4468 | void perf_event_mmap(struct vm_area_struct *vma) | |
4469 | { | |
4470 | struct perf_mmap_event mmap_event; | |
4471 | ||
4472 | if (!atomic_read(&nr_mmap_events)) | |
4473 | return; | |
4474 | ||
4475 | mmap_event = (struct perf_mmap_event){ | |
4476 | .vma = vma, | |
4477 | /* .file_name */ | |
4478 | /* .file_size */ | |
4479 | .event_id = { | |
4480 | .header = { | |
4481 | .type = PERF_RECORD_MMAP, | |
4482 | .misc = PERF_RECORD_MISC_USER, | |
4483 | /* .size */ | |
4484 | }, | |
4485 | /* .pid */ | |
4486 | /* .tid */ | |
4487 | .start = vma->vm_start, | |
4488 | .len = vma->vm_end - vma->vm_start, | |
4489 | .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, | |
4490 | }, | |
4491 | }; | |
4492 | ||
4493 | perf_event_mmap_event(&mmap_event); | |
4494 | } | |
4495 | ||
4496 | /* | |
4497 | * IRQ throttle logging | |
4498 | */ | |
4499 | ||
4500 | static void perf_log_throttle(struct perf_event *event, int enable) | |
4501 | { | |
4502 | struct perf_output_handle handle; | |
4503 | struct perf_sample_data sample; | |
4504 | int ret; | |
4505 | ||
4506 | struct { | |
4507 | struct perf_event_header header; | |
4508 | u64 time; | |
4509 | u64 id; | |
4510 | u64 stream_id; | |
4511 | } throttle_event = { | |
4512 | .header = { | |
4513 | .type = PERF_RECORD_THROTTLE, | |
4514 | .misc = 0, | |
4515 | .size = sizeof(throttle_event), | |
4516 | }, | |
4517 | .time = perf_clock(), | |
4518 | .id = primary_event_id(event), | |
4519 | .stream_id = event->id, | |
4520 | }; | |
4521 | ||
4522 | if (enable) | |
4523 | throttle_event.header.type = PERF_RECORD_UNTHROTTLE; | |
4524 | ||
4525 | perf_event_header__init_id(&throttle_event.header, &sample, event); | |
4526 | ||
4527 | ret = perf_output_begin(&handle, event, | |
4528 | throttle_event.header.size); | |
4529 | if (ret) | |
4530 | return; | |
4531 | ||
4532 | perf_output_put(&handle, throttle_event); | |
4533 | perf_event__output_id_sample(event, &handle, &sample); | |
4534 | perf_output_end(&handle); | |
4535 | } | |
4536 | ||
4537 | /* | |
4538 | * Generic event overflow handling, sampling. | |
4539 | */ | |
4540 | ||
4541 | static int __perf_event_overflow(struct perf_event *event, | |
4542 | int throttle, struct perf_sample_data *data, | |
4543 | struct pt_regs *regs) | |
4544 | { | |
4545 | int events = atomic_read(&event->event_limit); | |
4546 | struct hw_perf_event *hwc = &event->hw; | |
4547 | u64 seq; | |
4548 | int ret = 0; | |
4549 | ||
4550 | /* | |
4551 | * Non-sampling counters might still use the PMI to fold short | |
4552 | * hardware counters, ignore those. | |
4553 | */ | |
4554 | if (unlikely(!is_sampling_event(event))) | |
4555 | return 0; | |
4556 | ||
4557 | seq = __this_cpu_read(perf_throttled_seq); | |
4558 | if (seq != hwc->interrupts_seq) { | |
4559 | hwc->interrupts_seq = seq; | |
4560 | hwc->interrupts = 1; | |
4561 | } else { | |
4562 | hwc->interrupts++; | |
4563 | if (unlikely(throttle | |
4564 | && hwc->interrupts >= max_samples_per_tick)) { | |
4565 | __this_cpu_inc(perf_throttled_count); | |
4566 | hwc->interrupts = MAX_INTERRUPTS; | |
4567 | perf_log_throttle(event, 0); | |
4568 | ret = 1; | |
4569 | } | |
4570 | } | |
4571 | ||
4572 | if (event->attr.freq) { | |
4573 | u64 now = perf_clock(); | |
4574 | s64 delta = now - hwc->freq_time_stamp; | |
4575 | ||
4576 | hwc->freq_time_stamp = now; | |
4577 | ||
4578 | if (delta > 0 && delta < 2*TICK_NSEC) | |
4579 | perf_adjust_period(event, delta, hwc->last_period, true); | |
4580 | } | |
4581 | ||
4582 | /* | |
4583 | * XXX event_limit might not quite work as expected on inherited | |
4584 | * events | |
4585 | */ | |
4586 | ||
4587 | event->pending_kill = POLL_IN; | |
4588 | if (events && atomic_dec_and_test(&event->event_limit)) { | |
4589 | ret = 1; | |
4590 | event->pending_kill = POLL_HUP; | |
4591 | event->pending_disable = 1; | |
4592 | irq_work_queue(&event->pending); | |
4593 | } | |
4594 | ||
4595 | if (event->overflow_handler) | |
4596 | event->overflow_handler(event, data, regs); | |
4597 | else | |
4598 | perf_event_output(event, data, regs); | |
4599 | ||
4600 | if (event->fasync && event->pending_kill) { | |
4601 | event->pending_wakeup = 1; | |
4602 | irq_work_queue(&event->pending); | |
4603 | } | |
4604 | ||
4605 | return ret; | |
4606 | } | |
4607 | ||
4608 | int perf_event_overflow(struct perf_event *event, | |
4609 | struct perf_sample_data *data, | |
4610 | struct pt_regs *regs) | |
4611 | { | |
4612 | return __perf_event_overflow(event, 1, data, regs); | |
4613 | } | |
4614 | ||
4615 | /* | |
4616 | * Generic software event infrastructure | |
4617 | */ | |
4618 | ||
4619 | struct swevent_htable { | |
4620 | struct swevent_hlist *swevent_hlist; | |
4621 | struct mutex hlist_mutex; | |
4622 | int hlist_refcount; | |
4623 | ||
4624 | /* Recursion avoidance in each contexts */ | |
4625 | int recursion[PERF_NR_CONTEXTS]; | |
4626 | }; | |
4627 | ||
4628 | static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); | |
4629 | ||
4630 | /* | |
4631 | * We directly increment event->count and keep a second value in | |
4632 | * event->hw.period_left to count intervals. This period event | |
4633 | * is kept in the range [-sample_period, 0] so that we can use the | |
4634 | * sign as trigger. | |
4635 | */ | |
4636 | ||
4637 | static u64 perf_swevent_set_period(struct perf_event *event) | |
4638 | { | |
4639 | struct hw_perf_event *hwc = &event->hw; | |
4640 | u64 period = hwc->last_period; | |
4641 | u64 nr, offset; | |
4642 | s64 old, val; | |
4643 | ||
4644 | hwc->last_period = hwc->sample_period; | |
4645 | ||
4646 | again: | |
4647 | old = val = local64_read(&hwc->period_left); | |
4648 | if (val < 0) | |
4649 | return 0; | |
4650 | ||
4651 | nr = div64_u64(period + val, period); | |
4652 | offset = nr * period; | |
4653 | val -= offset; | |
4654 | if (local64_cmpxchg(&hwc->period_left, old, val) != old) | |
4655 | goto again; | |
4656 | ||
4657 | return nr; | |
4658 | } | |
4659 | ||
4660 | static void perf_swevent_overflow(struct perf_event *event, u64 overflow, | |
4661 | struct perf_sample_data *data, | |
4662 | struct pt_regs *regs) | |
4663 | { | |
4664 | struct hw_perf_event *hwc = &event->hw; | |
4665 | int throttle = 0; | |
4666 | ||
4667 | if (!overflow) | |
4668 | overflow = perf_swevent_set_period(event); | |
4669 | ||
4670 | if (hwc->interrupts == MAX_INTERRUPTS) | |
4671 | return; | |
4672 | ||
4673 | for (; overflow; overflow--) { | |
4674 | if (__perf_event_overflow(event, throttle, | |
4675 | data, regs)) { | |
4676 | /* | |
4677 | * We inhibit the overflow from happening when | |
4678 | * hwc->interrupts == MAX_INTERRUPTS. | |
4679 | */ | |
4680 | break; | |
4681 | } | |
4682 | throttle = 1; | |
4683 | } | |
4684 | } | |
4685 | ||
4686 | static void perf_swevent_event(struct perf_event *event, u64 nr, | |
4687 | struct perf_sample_data *data, | |
4688 | struct pt_regs *regs) | |
4689 | { | |
4690 | struct hw_perf_event *hwc = &event->hw; | |
4691 | ||
4692 | local64_add(nr, &event->count); | |
4693 | ||
4694 | if (!regs) | |
4695 | return; | |
4696 | ||
4697 | if (!is_sampling_event(event)) | |
4698 | return; | |
4699 | ||
4700 | if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { | |
4701 | data->period = nr; | |
4702 | return perf_swevent_overflow(event, 1, data, regs); | |
4703 | } else | |
4704 | data->period = event->hw.last_period; | |
4705 | ||
4706 | if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) | |
4707 | return perf_swevent_overflow(event, 1, data, regs); | |
4708 | ||
4709 | if (local64_add_negative(nr, &hwc->period_left)) | |
4710 | return; | |
4711 | ||
4712 | perf_swevent_overflow(event, 0, data, regs); | |
4713 | } | |
4714 | ||
4715 | static int perf_exclude_event(struct perf_event *event, | |
4716 | struct pt_regs *regs) | |
4717 | { | |
4718 | if (event->hw.state & PERF_HES_STOPPED) | |
4719 | return 1; | |
4720 | ||
4721 | if (regs) { | |
4722 | if (event->attr.exclude_user && user_mode(regs)) | |
4723 | return 1; | |
4724 | ||
4725 | if (event->attr.exclude_kernel && !user_mode(regs)) | |
4726 | return 1; | |
4727 | } | |
4728 | ||
4729 | return 0; | |
4730 | } | |
4731 | ||
4732 | static int perf_swevent_match(struct perf_event *event, | |
4733 | enum perf_type_id type, | |
4734 | u32 event_id, | |
4735 | struct perf_sample_data *data, | |
4736 | struct pt_regs *regs) | |
4737 | { | |
4738 | if (event->attr.type != type) | |
4739 | return 0; | |
4740 | ||
4741 | if (event->attr.config != event_id) | |
4742 | return 0; | |
4743 | ||
4744 | if (perf_exclude_event(event, regs)) | |
4745 | return 0; | |
4746 | ||
4747 | return 1; | |
4748 | } | |
4749 | ||
4750 | static inline u64 swevent_hash(u64 type, u32 event_id) | |
4751 | { | |
4752 | u64 val = event_id | (type << 32); | |
4753 | ||
4754 | return hash_64(val, SWEVENT_HLIST_BITS); | |
4755 | } | |
4756 | ||
4757 | static inline struct hlist_head * | |
4758 | __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) | |
4759 | { | |
4760 | u64 hash = swevent_hash(type, event_id); | |
4761 | ||
4762 | return &hlist->heads[hash]; | |
4763 | } | |
4764 | ||
4765 | /* For the read side: events when they trigger */ | |
4766 | static inline struct hlist_head * | |
4767 | find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) | |
4768 | { | |
4769 | struct swevent_hlist *hlist; | |
4770 | ||
4771 | hlist = rcu_dereference(swhash->swevent_hlist); | |
4772 | if (!hlist) | |
4773 | return NULL; | |
4774 | ||
4775 | return __find_swevent_head(hlist, type, event_id); | |
4776 | } | |
4777 | ||
4778 | /* For the event head insertion and removal in the hlist */ | |
4779 | static inline struct hlist_head * | |
4780 | find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) | |
4781 | { | |
4782 | struct swevent_hlist *hlist; | |
4783 | u32 event_id = event->attr.config; | |
4784 | u64 type = event->attr.type; | |
4785 | ||
4786 | /* | |
4787 | * Event scheduling is always serialized against hlist allocation | |
4788 | * and release. Which makes the protected version suitable here. | |
4789 | * The context lock guarantees that. | |
4790 | */ | |
4791 | hlist = rcu_dereference_protected(swhash->swevent_hlist, | |
4792 | lockdep_is_held(&event->ctx->lock)); | |
4793 | if (!hlist) | |
4794 | return NULL; | |
4795 | ||
4796 | return __find_swevent_head(hlist, type, event_id); | |
4797 | } | |
4798 | ||
4799 | static void do_perf_sw_event(enum perf_type_id type, u32 event_id, | |
4800 | u64 nr, | |
4801 | struct perf_sample_data *data, | |
4802 | struct pt_regs *regs) | |
4803 | { | |
4804 | struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); | |
4805 | struct perf_event *event; | |
4806 | struct hlist_node *node; | |
4807 | struct hlist_head *head; | |
4808 | ||
4809 | rcu_read_lock(); | |
4810 | head = find_swevent_head_rcu(swhash, type, event_id); | |
4811 | if (!head) | |
4812 | goto end; | |
4813 | ||
4814 | hlist_for_each_entry_rcu(event, node, head, hlist_entry) { | |
4815 | if (perf_swevent_match(event, type, event_id, data, regs)) | |
4816 | perf_swevent_event(event, nr, data, regs); | |
4817 | } | |
4818 | end: | |
4819 | rcu_read_unlock(); | |
4820 | } | |
4821 | ||
4822 | int perf_swevent_get_recursion_context(void) | |
4823 | { | |
4824 | struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); | |
4825 | ||
4826 | return get_recursion_context(swhash->recursion); | |
4827 | } | |
4828 | EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); | |
4829 | ||
4830 | inline void perf_swevent_put_recursion_context(int rctx) | |
4831 | { | |
4832 | struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); | |
4833 | ||
4834 | put_recursion_context(swhash->recursion, rctx); | |
4835 | } | |
4836 | ||
4837 | void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) | |
4838 | { | |
4839 | struct perf_sample_data data; | |
4840 | int rctx; | |
4841 | ||
4842 | preempt_disable_notrace(); | |
4843 | rctx = perf_swevent_get_recursion_context(); | |
4844 | if (rctx < 0) | |
4845 | return; | |
4846 | ||
4847 | perf_sample_data_init(&data, addr); | |
4848 | ||
4849 | do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); | |
4850 | ||
4851 | perf_swevent_put_recursion_context(rctx); | |
4852 | preempt_enable_notrace(); | |
4853 | } | |
4854 | ||
4855 | static void perf_swevent_read(struct perf_event *event) | |
4856 | { | |
4857 | } | |
4858 | ||
4859 | static int perf_swevent_add(struct perf_event *event, int flags) | |
4860 | { | |
4861 | struct swevent_htable *swhash = &__get_cpu_var(swevent_htable); | |
4862 | struct hw_perf_event *hwc = &event->hw; | |
4863 | struct hlist_head *head; | |
4864 | ||
4865 | if (is_sampling_event(event)) { | |
4866 | hwc->last_period = hwc->sample_period; | |
4867 | perf_swevent_set_period(event); | |
4868 | } | |
4869 | ||
4870 | hwc->state = !(flags & PERF_EF_START); | |
4871 | ||
4872 | head = find_swevent_head(swhash, event); | |
4873 | if (WARN_ON_ONCE(!head)) | |
4874 | return -EINVAL; | |
4875 | ||
4876 | hlist_add_head_rcu(&event->hlist_entry, head); | |
4877 | ||
4878 | return 0; | |
4879 | } | |
4880 | ||
4881 | static void perf_swevent_del(struct perf_event *event, int flags) | |
4882 | { | |
4883 | hlist_del_rcu(&event->hlist_entry); | |
4884 | } | |
4885 | ||
4886 | static void perf_swevent_start(struct perf_event *event, int flags) | |
4887 | { | |
4888 | event->hw.state = 0; | |
4889 | } | |
4890 | ||
4891 | static void perf_swevent_stop(struct perf_event *event, int flags) | |
4892 | { | |
4893 | event->hw.state = PERF_HES_STOPPED; | |
4894 | } | |
4895 | ||
4896 | /* Deref the hlist from the update side */ | |
4897 | static inline struct swevent_hlist * | |
4898 | swevent_hlist_deref(struct swevent_htable *swhash) | |
4899 | { | |
4900 | return rcu_dereference_protected(swhash->swevent_hlist, | |
4901 | lockdep_is_held(&swhash->hlist_mutex)); | |
4902 | } | |
4903 | ||
4904 | static void swevent_hlist_release(struct swevent_htable *swhash) | |
4905 | { | |
4906 | struct swevent_hlist *hlist = swevent_hlist_deref(swhash); | |
4907 | ||
4908 | if (!hlist) | |
4909 | return; | |
4910 | ||
4911 | rcu_assign_pointer(swhash->swevent_hlist, NULL); | |
4912 | kfree_rcu(hlist, rcu_head); | |
4913 | } | |
4914 | ||
4915 | static void swevent_hlist_put_cpu(struct perf_event *event, int cpu) | |
4916 | { | |
4917 | struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); | |
4918 | ||
4919 | mutex_lock(&swhash->hlist_mutex); | |
4920 | ||
4921 | if (!--swhash->hlist_refcount) | |
4922 | swevent_hlist_release(swhash); | |
4923 | ||
4924 | mutex_unlock(&swhash->hlist_mutex); | |
4925 | } | |
4926 | ||
4927 | static void swevent_hlist_put(struct perf_event *event) | |
4928 | { | |
4929 | int cpu; | |
4930 | ||
4931 | if (event->cpu != -1) { | |
4932 | swevent_hlist_put_cpu(event, event->cpu); | |
4933 | return; | |
4934 | } | |
4935 | ||
4936 | for_each_possible_cpu(cpu) | |
4937 | swevent_hlist_put_cpu(event, cpu); | |
4938 | } | |
4939 | ||
4940 | static int swevent_hlist_get_cpu(struct perf_event *event, int cpu) | |
4941 | { | |
4942 | struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); | |
4943 | int err = 0; | |
4944 | ||
4945 | mutex_lock(&swhash->hlist_mutex); | |
4946 | ||
4947 | if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { | |
4948 | struct swevent_hlist *hlist; | |
4949 | ||
4950 | hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); | |
4951 | if (!hlist) { | |
4952 | err = -ENOMEM; | |
4953 | goto exit; | |
4954 | } | |
4955 | rcu_assign_pointer(swhash->swevent_hlist, hlist); | |
4956 | } | |
4957 | swhash->hlist_refcount++; | |
4958 | exit: | |
4959 | mutex_unlock(&swhash->hlist_mutex); | |
4960 | ||
4961 | return err; | |
4962 | } | |
4963 | ||
4964 | static int swevent_hlist_get(struct perf_event *event) | |
4965 | { | |
4966 | int err; | |
4967 | int cpu, failed_cpu; | |
4968 | ||
4969 | if (event->cpu != -1) | |
4970 | return swevent_hlist_get_cpu(event, event->cpu); | |
4971 | ||
4972 | get_online_cpus(); | |
4973 | for_each_possible_cpu(cpu) { | |
4974 | err = swevent_hlist_get_cpu(event, cpu); | |
4975 | if (err) { | |
4976 | failed_cpu = cpu; | |
4977 | goto fail; | |
4978 | } | |
4979 | } | |
4980 | put_online_cpus(); | |
4981 | ||
4982 | return 0; | |
4983 | fail: | |
4984 | for_each_possible_cpu(cpu) { | |
4985 | if (cpu == failed_cpu) | |
4986 | break; | |
4987 | swevent_hlist_put_cpu(event, cpu); | |
4988 | } | |
4989 | ||
4990 | put_online_cpus(); | |
4991 | return err; | |
4992 | } | |
4993 | ||
4994 | struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; | |
4995 | ||
4996 | static void sw_perf_event_destroy(struct perf_event *event) | |
4997 | { | |
4998 | u64 event_id = event->attr.config; | |
4999 | ||
5000 | WARN_ON(event->parent); | |
5001 | ||
5002 | static_key_slow_dec(&perf_swevent_enabled[event_id]); | |
5003 | swevent_hlist_put(event); | |
5004 | } | |
5005 | ||
5006 | static int perf_swevent_init(struct perf_event *event) | |
5007 | { | |
5008 | int event_id = event->attr.config; | |
5009 | ||
5010 | if (event->attr.type != PERF_TYPE_SOFTWARE) | |
5011 | return -ENOENT; | |
5012 | ||
5013 | switch (event_id) { | |
5014 | case PERF_COUNT_SW_CPU_CLOCK: | |
5015 | case PERF_COUNT_SW_TASK_CLOCK: | |
5016 | return -ENOENT; | |
5017 | ||
5018 | default: | |
5019 | break; | |
5020 | } | |
5021 | ||
5022 | if (event_id >= PERF_COUNT_SW_MAX) | |
5023 | return -ENOENT; | |
5024 | ||
5025 | if (!event->parent) { | |
5026 | int err; | |
5027 | ||
5028 | err = swevent_hlist_get(event); | |
5029 | if (err) | |
5030 | return err; | |
5031 | ||
5032 | static_key_slow_inc(&perf_swevent_enabled[event_id]); | |
5033 | event->destroy = sw_perf_event_destroy; | |
5034 | } | |
5035 | ||
5036 | return 0; | |
5037 | } | |
5038 | ||
5039 | static int perf_swevent_event_idx(struct perf_event *event) | |
5040 | { | |
5041 | return 0; | |
5042 | } | |
5043 | ||
5044 | static struct pmu perf_swevent = { | |
5045 | .task_ctx_nr = perf_sw_context, | |
5046 | ||
5047 | .event_init = perf_swevent_init, | |
5048 | .add = perf_swevent_add, | |
5049 | .del = perf_swevent_del, | |
5050 | .start = perf_swevent_start, | |
5051 | .stop = perf_swevent_stop, | |
5052 | .read = perf_swevent_read, | |
5053 | ||
5054 | .event_idx = perf_swevent_event_idx, | |
5055 | }; | |
5056 | ||
5057 | #ifdef CONFIG_EVENT_TRACING | |
5058 | ||
5059 | static int perf_tp_filter_match(struct perf_event *event, | |
5060 | struct perf_sample_data *data) | |
5061 | { | |
5062 | void *record = data->raw->data; | |
5063 | ||
5064 | if (likely(!event->filter) || filter_match_preds(event->filter, record)) | |
5065 | return 1; | |
5066 | return 0; | |
5067 | } | |
5068 | ||
5069 | static int perf_tp_event_match(struct perf_event *event, | |
5070 | struct perf_sample_data *data, | |
5071 | struct pt_regs *regs) | |
5072 | { | |
5073 | if (event->hw.state & PERF_HES_STOPPED) | |
5074 | return 0; | |
5075 | /* | |
5076 | * All tracepoints are from kernel-space. | |
5077 | */ | |
5078 | if (event->attr.exclude_kernel) | |
5079 | return 0; | |
5080 | ||
5081 | if (!perf_tp_filter_match(event, data)) | |
5082 | return 0; | |
5083 | ||
5084 | return 1; | |
5085 | } | |
5086 | ||
5087 | void perf_tp_event(u64 addr, u64 count, void *record, int entry_size, | |
5088 | struct pt_regs *regs, struct hlist_head *head, int rctx) | |
5089 | { | |
5090 | struct perf_sample_data data; | |
5091 | struct perf_event *event; | |
5092 | struct hlist_node *node; | |
5093 | ||
5094 | struct perf_raw_record raw = { | |
5095 | .size = entry_size, | |
5096 | .data = record, | |
5097 | }; | |
5098 | ||
5099 | perf_sample_data_init(&data, addr); | |
5100 | data.raw = &raw; | |
5101 | ||
5102 | hlist_for_each_entry_rcu(event, node, head, hlist_entry) { | |
5103 | if (perf_tp_event_match(event, &data, regs)) | |
5104 | perf_swevent_event(event, count, &data, regs); | |
5105 | } | |
5106 | ||
5107 | perf_swevent_put_recursion_context(rctx); | |
5108 | } | |
5109 | EXPORT_SYMBOL_GPL(perf_tp_event); | |
5110 | ||
5111 | static void tp_perf_event_destroy(struct perf_event *event) | |
5112 | { | |
5113 | perf_trace_destroy(event); | |
5114 | } | |
5115 | ||
5116 | static int perf_tp_event_init(struct perf_event *event) | |
5117 | { | |
5118 | int err; | |
5119 | ||
5120 | if (event->attr.type != PERF_TYPE_TRACEPOINT) | |
5121 | return -ENOENT; | |
5122 | ||
5123 | err = perf_trace_init(event); | |
5124 | if (err) | |
5125 | return err; | |
5126 | ||
5127 | event->destroy = tp_perf_event_destroy; | |
5128 | ||
5129 | return 0; | |
5130 | } | |
5131 | ||
5132 | static struct pmu perf_tracepoint = { | |
5133 | .task_ctx_nr = perf_sw_context, | |
5134 | ||
5135 | .event_init = perf_tp_event_init, | |
5136 | .add = perf_trace_add, | |
5137 | .del = perf_trace_del, | |
5138 | .start = perf_swevent_start, | |
5139 | .stop = perf_swevent_stop, | |
5140 | .read = perf_swevent_read, | |
5141 | ||
5142 | .event_idx = perf_swevent_event_idx, | |
5143 | }; | |
5144 | ||
5145 | static inline void perf_tp_register(void) | |
5146 | { | |
5147 | perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); | |
5148 | } | |
5149 | ||
5150 | static int perf_event_set_filter(struct perf_event *event, void __user *arg) | |
5151 | { | |
5152 | char *filter_str; | |
5153 | int ret; | |
5154 | ||
5155 | if (event->attr.type != PERF_TYPE_TRACEPOINT) | |
5156 | return -EINVAL; | |
5157 | ||
5158 | filter_str = strndup_user(arg, PAGE_SIZE); | |
5159 | if (IS_ERR(filter_str)) | |
5160 | return PTR_ERR(filter_str); | |
5161 | ||
5162 | ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); | |
5163 | ||
5164 | kfree(filter_str); | |
5165 | return ret; | |
5166 | } | |
5167 | ||
5168 | static void perf_event_free_filter(struct perf_event *event) | |
5169 | { | |
5170 | ftrace_profile_free_filter(event); | |
5171 | } | |
5172 | ||
5173 | #else | |
5174 | ||
5175 | static inline void perf_tp_register(void) | |
5176 | { | |
5177 | } | |
5178 | ||
5179 | static int perf_event_set_filter(struct perf_event *event, void __user *arg) | |
5180 | { | |
5181 | return -ENOENT; | |
5182 | } | |
5183 | ||
5184 | static void perf_event_free_filter(struct perf_event *event) | |
5185 | { | |
5186 | } | |
5187 | ||
5188 | #endif /* CONFIG_EVENT_TRACING */ | |
5189 | ||
5190 | #ifdef CONFIG_HAVE_HW_BREAKPOINT | |
5191 | void perf_bp_event(struct perf_event *bp, void *data) | |
5192 | { | |
5193 | struct perf_sample_data sample; | |
5194 | struct pt_regs *regs = data; | |
5195 | ||
5196 | perf_sample_data_init(&sample, bp->attr.bp_addr); | |
5197 | ||
5198 | if (!bp->hw.state && !perf_exclude_event(bp, regs)) | |
5199 | perf_swevent_event(bp, 1, &sample, regs); | |
5200 | } | |
5201 | #endif | |
5202 | ||
5203 | /* | |
5204 | * hrtimer based swevent callback | |
5205 | */ | |
5206 | ||
5207 | static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) | |
5208 | { | |
5209 | enum hrtimer_restart ret = HRTIMER_RESTART; | |
5210 | struct perf_sample_data data; | |
5211 | struct pt_regs *regs; | |
5212 | struct perf_event *event; | |
5213 | u64 period; | |
5214 | ||
5215 | event = container_of(hrtimer, struct perf_event, hw.hrtimer); | |
5216 | ||
5217 | if (event->state != PERF_EVENT_STATE_ACTIVE) | |
5218 | return HRTIMER_NORESTART; | |
5219 | ||
5220 | event->pmu->read(event); | |
5221 | ||
5222 | perf_sample_data_init(&data, 0); | |
5223 | data.period = event->hw.last_period; | |
5224 | regs = get_irq_regs(); | |
5225 | ||
5226 | if (regs && !perf_exclude_event(event, regs)) { | |
5227 | if (!(event->attr.exclude_idle && is_idle_task(current))) | |
5228 | if (perf_event_overflow(event, &data, regs)) | |
5229 | ret = HRTIMER_NORESTART; | |
5230 | } | |
5231 | ||
5232 | period = max_t(u64, 10000, event->hw.sample_period); | |
5233 | hrtimer_forward_now(hrtimer, ns_to_ktime(period)); | |
5234 | ||
5235 | return ret; | |
5236 | } | |
5237 | ||
5238 | static void perf_swevent_start_hrtimer(struct perf_event *event) | |
5239 | { | |
5240 | struct hw_perf_event *hwc = &event->hw; | |
5241 | s64 period; | |
5242 | ||
5243 | if (!is_sampling_event(event)) | |
5244 | return; | |
5245 | ||
5246 | period = local64_read(&hwc->period_left); | |
5247 | if (period) { | |
5248 | if (period < 0) | |
5249 | period = 10000; | |
5250 | ||
5251 | local64_set(&hwc->period_left, 0); | |
5252 | } else { | |
5253 | period = max_t(u64, 10000, hwc->sample_period); | |
5254 | } | |
5255 | __hrtimer_start_range_ns(&hwc->hrtimer, | |
5256 | ns_to_ktime(period), 0, | |
5257 | HRTIMER_MODE_REL_PINNED, 0); | |
5258 | } | |
5259 | ||
5260 | static void perf_swevent_cancel_hrtimer(struct perf_event *event) | |
5261 | { | |
5262 | struct hw_perf_event *hwc = &event->hw; | |
5263 | ||
5264 | if (is_sampling_event(event)) { | |
5265 | ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); | |
5266 | local64_set(&hwc->period_left, ktime_to_ns(remaining)); | |
5267 | ||
5268 | hrtimer_cancel(&hwc->hrtimer); | |
5269 | } | |
5270 | } | |
5271 | ||
5272 | static void perf_swevent_init_hrtimer(struct perf_event *event) | |
5273 | { | |
5274 | struct hw_perf_event *hwc = &event->hw; | |
5275 | ||
5276 | if (!is_sampling_event(event)) | |
5277 | return; | |
5278 | ||
5279 | hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
5280 | hwc->hrtimer.function = perf_swevent_hrtimer; | |
5281 | ||
5282 | /* | |
5283 | * Since hrtimers have a fixed rate, we can do a static freq->period | |
5284 | * mapping and avoid the whole period adjust feedback stuff. | |
5285 | */ | |
5286 | if (event->attr.freq) { | |
5287 | long freq = event->attr.sample_freq; | |
5288 | ||
5289 | event->attr.sample_period = NSEC_PER_SEC / freq; | |
5290 | hwc->sample_period = event->attr.sample_period; | |
5291 | local64_set(&hwc->period_left, hwc->sample_period); | |
5292 | event->attr.freq = 0; | |
5293 | } | |
5294 | } | |
5295 | ||
5296 | /* | |
5297 | * Software event: cpu wall time clock | |
5298 | */ | |
5299 | ||
5300 | static void cpu_clock_event_update(struct perf_event *event) | |
5301 | { | |
5302 | s64 prev; | |
5303 | u64 now; | |
5304 | ||
5305 | now = local_clock(); | |
5306 | prev = local64_xchg(&event->hw.prev_count, now); | |
5307 | local64_add(now - prev, &event->count); | |
5308 | } | |
5309 | ||
5310 | static void cpu_clock_event_start(struct perf_event *event, int flags) | |
5311 | { | |
5312 | local64_set(&event->hw.prev_count, local_clock()); | |
5313 | perf_swevent_start_hrtimer(event); | |
5314 | } | |
5315 | ||
5316 | static void cpu_clock_event_stop(struct perf_event *event, int flags) | |
5317 | { | |
5318 | perf_swevent_cancel_hrtimer(event); | |
5319 | cpu_clock_event_update(event); | |
5320 | } | |
5321 | ||
5322 | static int cpu_clock_event_add(struct perf_event *event, int flags) | |
5323 | { | |
5324 | if (flags & PERF_EF_START) | |
5325 | cpu_clock_event_start(event, flags); | |
5326 | ||
5327 | return 0; | |
5328 | } | |
5329 | ||
5330 | static void cpu_clock_event_del(struct perf_event *event, int flags) | |
5331 | { | |
5332 | cpu_clock_event_stop(event, flags); | |
5333 | } | |
5334 | ||
5335 | static void cpu_clock_event_read(struct perf_event *event) | |
5336 | { | |
5337 | cpu_clock_event_update(event); | |
5338 | } | |
5339 | ||
5340 | static int cpu_clock_event_init(struct perf_event *event) | |
5341 | { | |
5342 | if (event->attr.type != PERF_TYPE_SOFTWARE) | |
5343 | return -ENOENT; | |
5344 | ||
5345 | if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) | |
5346 | return -ENOENT; | |
5347 | ||
5348 | perf_swevent_init_hrtimer(event); | |
5349 | ||
5350 | return 0; | |
5351 | } | |
5352 | ||
5353 | static struct pmu perf_cpu_clock = { | |
5354 | .task_ctx_nr = perf_sw_context, | |
5355 | ||
5356 | .event_init = cpu_clock_event_init, | |
5357 | .add = cpu_clock_event_add, | |
5358 | .del = cpu_clock_event_del, | |
5359 | .start = cpu_clock_event_start, | |
5360 | .stop = cpu_clock_event_stop, | |
5361 | .read = cpu_clock_event_read, | |
5362 | ||
5363 | .event_idx = perf_swevent_event_idx, | |
5364 | }; | |
5365 | ||
5366 | /* | |
5367 | * Software event: task time clock | |
5368 | */ | |
5369 | ||
5370 | static void task_clock_event_update(struct perf_event *event, u64 now) | |
5371 | { | |
5372 | u64 prev; | |
5373 | s64 delta; | |
5374 | ||
5375 | prev = local64_xchg(&event->hw.prev_count, now); | |
5376 | delta = now - prev; | |
5377 | local64_add(delta, &event->count); | |
5378 | } | |
5379 | ||
5380 | static void task_clock_event_start(struct perf_event *event, int flags) | |
5381 | { | |
5382 | local64_set(&event->hw.prev_count, event->ctx->time); | |
5383 | perf_swevent_start_hrtimer(event); | |
5384 | } | |
5385 | ||
5386 | static void task_clock_event_stop(struct perf_event *event, int flags) | |
5387 | { | |
5388 | perf_swevent_cancel_hrtimer(event); | |
5389 | task_clock_event_update(event, event->ctx->time); | |
5390 | } | |
5391 | ||
5392 | static int task_clock_event_add(struct perf_event *event, int flags) | |
5393 | { | |
5394 | if (flags & PERF_EF_START) | |
5395 | task_clock_event_start(event, flags); | |
5396 | ||
5397 | return 0; | |
5398 | } | |
5399 | ||
5400 | static void task_clock_event_del(struct perf_event *event, int flags) | |
5401 | { | |
5402 | task_clock_event_stop(event, PERF_EF_UPDATE); | |
5403 | } | |
5404 | ||
5405 | static void task_clock_event_read(struct perf_event *event) | |
5406 | { | |
5407 | u64 now = perf_clock(); | |
5408 | u64 delta = now - event->ctx->timestamp; | |
5409 | u64 time = event->ctx->time + delta; | |
5410 | ||
5411 | task_clock_event_update(event, time); | |
5412 | } | |
5413 | ||
5414 | static int task_clock_event_init(struct perf_event *event) | |
5415 | { | |
5416 | if (event->attr.type != PERF_TYPE_SOFTWARE) | |
5417 | return -ENOENT; | |
5418 | ||
5419 | if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) | |
5420 | return -ENOENT; | |
5421 | ||
5422 | perf_swevent_init_hrtimer(event); | |
5423 | ||
5424 | return 0; | |
5425 | } | |
5426 | ||
5427 | static struct pmu perf_task_clock = { | |
5428 | .task_ctx_nr = perf_sw_context, | |
5429 | ||
5430 | .event_init = task_clock_event_init, | |
5431 | .add = task_clock_event_add, | |
5432 | .del = task_clock_event_del, | |
5433 | .start = task_clock_event_start, | |
5434 | .stop = task_clock_event_stop, | |
5435 | .read = task_clock_event_read, | |
5436 | ||
5437 | .event_idx = perf_swevent_event_idx, | |
5438 | }; | |
5439 | ||
5440 | static void perf_pmu_nop_void(struct pmu *pmu) | |
5441 | { | |
5442 | } | |
5443 | ||
5444 | static int perf_pmu_nop_int(struct pmu *pmu) | |
5445 | { | |
5446 | return 0; | |
5447 | } | |
5448 | ||
5449 | static void perf_pmu_start_txn(struct pmu *pmu) | |
5450 | { | |
5451 | perf_pmu_disable(pmu); | |
5452 | } | |
5453 | ||
5454 | static int perf_pmu_commit_txn(struct pmu *pmu) | |
5455 | { | |
5456 | perf_pmu_enable(pmu); | |
5457 | return 0; | |
5458 | } | |
5459 | ||
5460 | static void perf_pmu_cancel_txn(struct pmu *pmu) | |
5461 | { | |
5462 | perf_pmu_enable(pmu); | |
5463 | } | |
5464 | ||
5465 | static int perf_event_idx_default(struct perf_event *event) | |
5466 | { | |
5467 | return event->hw.idx + 1; | |
5468 | } | |
5469 | ||
5470 | /* | |
5471 | * Ensures all contexts with the same task_ctx_nr have the same | |
5472 | * pmu_cpu_context too. | |
5473 | */ | |
5474 | static void *find_pmu_context(int ctxn) | |
5475 | { | |
5476 | struct pmu *pmu; | |
5477 | ||
5478 | if (ctxn < 0) | |
5479 | return NULL; | |
5480 | ||
5481 | list_for_each_entry(pmu, &pmus, entry) { | |
5482 | if (pmu->task_ctx_nr == ctxn) | |
5483 | return pmu->pmu_cpu_context; | |
5484 | } | |
5485 | ||
5486 | return NULL; | |
5487 | } | |
5488 | ||
5489 | static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) | |
5490 | { | |
5491 | int cpu; | |
5492 | ||
5493 | for_each_possible_cpu(cpu) { | |
5494 | struct perf_cpu_context *cpuctx; | |
5495 | ||
5496 | cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); | |
5497 | ||
5498 | if (cpuctx->active_pmu == old_pmu) | |
5499 | cpuctx->active_pmu = pmu; | |
5500 | } | |
5501 | } | |
5502 | ||
5503 | static void free_pmu_context(struct pmu *pmu) | |
5504 | { | |
5505 | struct pmu *i; | |
5506 | ||
5507 | mutex_lock(&pmus_lock); | |
5508 | /* | |
5509 | * Like a real lame refcount. | |
5510 | */ | |
5511 | list_for_each_entry(i, &pmus, entry) { | |
5512 | if (i->pmu_cpu_context == pmu->pmu_cpu_context) { | |
5513 | update_pmu_context(i, pmu); | |
5514 | goto out; | |
5515 | } | |
5516 | } | |
5517 | ||
5518 | free_percpu(pmu->pmu_cpu_context); | |
5519 | out: | |
5520 | mutex_unlock(&pmus_lock); | |
5521 | } | |
5522 | static struct idr pmu_idr; | |
5523 | ||
5524 | static ssize_t | |
5525 | type_show(struct device *dev, struct device_attribute *attr, char *page) | |
5526 | { | |
5527 | struct pmu *pmu = dev_get_drvdata(dev); | |
5528 | ||
5529 | return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); | |
5530 | } | |
5531 | ||
5532 | static struct device_attribute pmu_dev_attrs[] = { | |
5533 | __ATTR_RO(type), | |
5534 | __ATTR_NULL, | |
5535 | }; | |
5536 | ||
5537 | static int pmu_bus_running; | |
5538 | static struct bus_type pmu_bus = { | |
5539 | .name = "event_source", | |
5540 | .dev_attrs = pmu_dev_attrs, | |
5541 | }; | |
5542 | ||
5543 | static void pmu_dev_release(struct device *dev) | |
5544 | { | |
5545 | kfree(dev); | |
5546 | } | |
5547 | ||
5548 | static int pmu_dev_alloc(struct pmu *pmu) | |
5549 | { | |
5550 | int ret = -ENOMEM; | |
5551 | ||
5552 | pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); | |
5553 | if (!pmu->dev) | |
5554 | goto out; | |
5555 | ||
5556 | pmu->dev->groups = pmu->attr_groups; | |
5557 | device_initialize(pmu->dev); | |
5558 | ret = dev_set_name(pmu->dev, "%s", pmu->name); | |
5559 | if (ret) | |
5560 | goto free_dev; | |
5561 | ||
5562 | dev_set_drvdata(pmu->dev, pmu); | |
5563 | pmu->dev->bus = &pmu_bus; | |
5564 | pmu->dev->release = pmu_dev_release; | |
5565 | ret = device_add(pmu->dev); | |
5566 | if (ret) | |
5567 | goto free_dev; | |
5568 | ||
5569 | out: | |
5570 | return ret; | |
5571 | ||
5572 | free_dev: | |
5573 | put_device(pmu->dev); | |
5574 | goto out; | |
5575 | } | |
5576 | ||
5577 | static struct lock_class_key cpuctx_mutex; | |
5578 | static struct lock_class_key cpuctx_lock; | |
5579 | ||
5580 | int perf_pmu_register(struct pmu *pmu, char *name, int type) | |
5581 | { | |
5582 | int cpu, ret; | |
5583 | ||
5584 | mutex_lock(&pmus_lock); | |
5585 | ret = -ENOMEM; | |
5586 | pmu->pmu_disable_count = alloc_percpu(int); | |
5587 | if (!pmu->pmu_disable_count) | |
5588 | goto unlock; | |
5589 | ||
5590 | pmu->type = -1; | |
5591 | if (!name) | |
5592 | goto skip_type; | |
5593 | pmu->name = name; | |
5594 | ||
5595 | if (type < 0) { | |
5596 | int err = idr_pre_get(&pmu_idr, GFP_KERNEL); | |
5597 | if (!err) | |
5598 | goto free_pdc; | |
5599 | ||
5600 | err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type); | |
5601 | if (err) { | |
5602 | ret = err; | |
5603 | goto free_pdc; | |
5604 | } | |
5605 | } | |
5606 | pmu->type = type; | |
5607 | ||
5608 | if (pmu_bus_running) { | |
5609 | ret = pmu_dev_alloc(pmu); | |
5610 | if (ret) | |
5611 | goto free_idr; | |
5612 | } | |
5613 | ||
5614 | skip_type: | |
5615 | pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); | |
5616 | if (pmu->pmu_cpu_context) | |
5617 | goto got_cpu_context; | |
5618 | ||
5619 | pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); | |
5620 | if (!pmu->pmu_cpu_context) | |
5621 | goto free_dev; | |
5622 | ||
5623 | for_each_possible_cpu(cpu) { | |
5624 | struct perf_cpu_context *cpuctx; | |
5625 | ||
5626 | cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); | |
5627 | __perf_event_init_context(&cpuctx->ctx); | |
5628 | lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); | |
5629 | lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); | |
5630 | cpuctx->ctx.type = cpu_context; | |
5631 | cpuctx->ctx.pmu = pmu; | |
5632 | cpuctx->jiffies_interval = 1; | |
5633 | INIT_LIST_HEAD(&cpuctx->rotation_list); | |
5634 | cpuctx->active_pmu = pmu; | |
5635 | } | |
5636 | ||
5637 | got_cpu_context: | |
5638 | if (!pmu->start_txn) { | |
5639 | if (pmu->pmu_enable) { | |
5640 | /* | |
5641 | * If we have pmu_enable/pmu_disable calls, install | |
5642 | * transaction stubs that use that to try and batch | |
5643 | * hardware accesses. | |
5644 | */ | |
5645 | pmu->start_txn = perf_pmu_start_txn; | |
5646 | pmu->commit_txn = perf_pmu_commit_txn; | |
5647 | pmu->cancel_txn = perf_pmu_cancel_txn; | |
5648 | } else { | |
5649 | pmu->start_txn = perf_pmu_nop_void; | |
5650 | pmu->commit_txn = perf_pmu_nop_int; | |
5651 | pmu->cancel_txn = perf_pmu_nop_void; | |
5652 | } | |
5653 | } | |
5654 | ||
5655 | if (!pmu->pmu_enable) { | |
5656 | pmu->pmu_enable = perf_pmu_nop_void; | |
5657 | pmu->pmu_disable = perf_pmu_nop_void; | |
5658 | } | |
5659 | ||
5660 | if (!pmu->event_idx) | |
5661 | pmu->event_idx = perf_event_idx_default; | |
5662 | ||
5663 | list_add_rcu(&pmu->entry, &pmus); | |
5664 | ret = 0; | |
5665 | unlock: | |
5666 | mutex_unlock(&pmus_lock); | |
5667 | ||
5668 | return ret; | |
5669 | ||
5670 | free_dev: | |
5671 | device_del(pmu->dev); | |
5672 | put_device(pmu->dev); | |
5673 | ||
5674 | free_idr: | |
5675 | if (pmu->type >= PERF_TYPE_MAX) | |
5676 | idr_remove(&pmu_idr, pmu->type); | |
5677 | ||
5678 | free_pdc: | |
5679 | free_percpu(pmu->pmu_disable_count); | |
5680 | goto unlock; | |
5681 | } | |
5682 | ||
5683 | void perf_pmu_unregister(struct pmu *pmu) | |
5684 | { | |
5685 | mutex_lock(&pmus_lock); | |
5686 | list_del_rcu(&pmu->entry); | |
5687 | mutex_unlock(&pmus_lock); | |
5688 | ||
5689 | /* | |
5690 | * We dereference the pmu list under both SRCU and regular RCU, so | |
5691 | * synchronize against both of those. | |
5692 | */ | |
5693 | synchronize_srcu(&pmus_srcu); | |
5694 | synchronize_rcu(); | |
5695 | ||
5696 | free_percpu(pmu->pmu_disable_count); | |
5697 | if (pmu->type >= PERF_TYPE_MAX) | |
5698 | idr_remove(&pmu_idr, pmu->type); | |
5699 | device_del(pmu->dev); | |
5700 | put_device(pmu->dev); | |
5701 | free_pmu_context(pmu); | |
5702 | } | |
5703 | ||
5704 | struct pmu *perf_init_event(struct perf_event *event) | |
5705 | { | |
5706 | struct pmu *pmu = NULL; | |
5707 | int idx; | |
5708 | int ret; | |
5709 | ||
5710 | idx = srcu_read_lock(&pmus_srcu); | |
5711 | ||
5712 | rcu_read_lock(); | |
5713 | pmu = idr_find(&pmu_idr, event->attr.type); | |
5714 | rcu_read_unlock(); | |
5715 | if (pmu) { | |
5716 | event->pmu = pmu; | |
5717 | ret = pmu->event_init(event); | |
5718 | if (ret) | |
5719 | pmu = ERR_PTR(ret); | |
5720 | goto unlock; | |
5721 | } | |
5722 | ||
5723 | list_for_each_entry_rcu(pmu, &pmus, entry) { | |
5724 | event->pmu = pmu; | |
5725 | ret = pmu->event_init(event); | |
5726 | if (!ret) | |
5727 | goto unlock; | |
5728 | ||
5729 | if (ret != -ENOENT) { | |
5730 | pmu = ERR_PTR(ret); | |
5731 | goto unlock; | |
5732 | } | |
5733 | } | |
5734 | pmu = ERR_PTR(-ENOENT); | |
5735 | unlock: | |
5736 | srcu_read_unlock(&pmus_srcu, idx); | |
5737 | ||
5738 | return pmu; | |
5739 | } | |
5740 | ||
5741 | /* | |
5742 | * Allocate and initialize a event structure | |
5743 | */ | |
5744 | static struct perf_event * | |
5745 | perf_event_alloc(struct perf_event_attr *attr, int cpu, | |
5746 | struct task_struct *task, | |
5747 | struct perf_event *group_leader, | |
5748 | struct perf_event *parent_event, | |
5749 | perf_overflow_handler_t overflow_handler, | |
5750 | void *context) | |
5751 | { | |
5752 | struct pmu *pmu; | |
5753 | struct perf_event *event; | |
5754 | struct hw_perf_event *hwc; | |
5755 | long err; | |
5756 | ||
5757 | if ((unsigned)cpu >= nr_cpu_ids) { | |
5758 | if (!task || cpu != -1) | |
5759 | return ERR_PTR(-EINVAL); | |
5760 | } | |
5761 | ||
5762 | event = kzalloc(sizeof(*event), GFP_KERNEL); | |
5763 | if (!event) | |
5764 | return ERR_PTR(-ENOMEM); | |
5765 | ||
5766 | /* | |
5767 | * Single events are their own group leaders, with an | |
5768 | * empty sibling list: | |
5769 | */ | |
5770 | if (!group_leader) | |
5771 | group_leader = event; | |
5772 | ||
5773 | mutex_init(&event->child_mutex); | |
5774 | INIT_LIST_HEAD(&event->child_list); | |
5775 | ||
5776 | INIT_LIST_HEAD(&event->group_entry); | |
5777 | INIT_LIST_HEAD(&event->event_entry); | |
5778 | INIT_LIST_HEAD(&event->sibling_list); | |
5779 | INIT_LIST_HEAD(&event->rb_entry); | |
5780 | ||
5781 | init_waitqueue_head(&event->waitq); | |
5782 | init_irq_work(&event->pending, perf_pending_event); | |
5783 | ||
5784 | mutex_init(&event->mmap_mutex); | |
5785 | ||
5786 | event->cpu = cpu; | |
5787 | event->attr = *attr; | |
5788 | event->group_leader = group_leader; | |
5789 | event->pmu = NULL; | |
5790 | event->oncpu = -1; | |
5791 | ||
5792 | event->parent = parent_event; | |
5793 | ||
5794 | event->ns = get_pid_ns(current->nsproxy->pid_ns); | |
5795 | event->id = atomic64_inc_return(&perf_event_id); | |
5796 | ||
5797 | event->state = PERF_EVENT_STATE_INACTIVE; | |
5798 | ||
5799 | if (task) { | |
5800 | event->attach_state = PERF_ATTACH_TASK; | |
5801 | #ifdef CONFIG_HAVE_HW_BREAKPOINT | |
5802 | /* | |
5803 | * hw_breakpoint is a bit difficult here.. | |
5804 | */ | |
5805 | if (attr->type == PERF_TYPE_BREAKPOINT) | |
5806 | event->hw.bp_target = task; | |
5807 | #endif | |
5808 | } | |
5809 | ||
5810 | if (!overflow_handler && parent_event) { | |
5811 | overflow_handler = parent_event->overflow_handler; | |
5812 | context = parent_event->overflow_handler_context; | |
5813 | } | |
5814 | ||
5815 | event->overflow_handler = overflow_handler; | |
5816 | event->overflow_handler_context = context; | |
5817 | ||
5818 | if (attr->disabled) | |
5819 | event->state = PERF_EVENT_STATE_OFF; | |
5820 | ||
5821 | pmu = NULL; | |
5822 | ||
5823 | hwc = &event->hw; | |
5824 | hwc->sample_period = attr->sample_period; | |
5825 | if (attr->freq && attr->sample_freq) | |
5826 | hwc->sample_period = 1; | |
5827 | hwc->last_period = hwc->sample_period; | |
5828 | ||
5829 | local64_set(&hwc->period_left, hwc->sample_period); | |
5830 | ||
5831 | /* | |
5832 | * we currently do not support PERF_FORMAT_GROUP on inherited events | |
5833 | */ | |
5834 | if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) | |
5835 | goto done; | |
5836 | ||
5837 | pmu = perf_init_event(event); | |
5838 | ||
5839 | done: | |
5840 | err = 0; | |
5841 | if (!pmu) | |
5842 | err = -EINVAL; | |
5843 | else if (IS_ERR(pmu)) | |
5844 | err = PTR_ERR(pmu); | |
5845 | ||
5846 | if (err) { | |
5847 | if (event->ns) | |
5848 | put_pid_ns(event->ns); | |
5849 | kfree(event); | |
5850 | return ERR_PTR(err); | |
5851 | } | |
5852 | ||
5853 | if (!event->parent) { | |
5854 | if (event->attach_state & PERF_ATTACH_TASK) | |
5855 | static_key_slow_inc(&perf_sched_events.key); | |
5856 | if (event->attr.mmap || event->attr.mmap_data) | |
5857 | atomic_inc(&nr_mmap_events); | |
5858 | if (event->attr.comm) | |
5859 | atomic_inc(&nr_comm_events); | |
5860 | if (event->attr.task) | |
5861 | atomic_inc(&nr_task_events); | |
5862 | if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { | |
5863 | err = get_callchain_buffers(); | |
5864 | if (err) { | |
5865 | free_event(event); | |
5866 | return ERR_PTR(err); | |
5867 | } | |
5868 | } | |
5869 | } | |
5870 | ||
5871 | return event; | |
5872 | } | |
5873 | ||
5874 | static int perf_copy_attr(struct perf_event_attr __user *uattr, | |
5875 | struct perf_event_attr *attr) | |
5876 | { | |
5877 | u32 size; | |
5878 | int ret; | |
5879 | ||
5880 | if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) | |
5881 | return -EFAULT; | |
5882 | ||
5883 | /* | |
5884 | * zero the full structure, so that a short copy will be nice. | |
5885 | */ | |
5886 | memset(attr, 0, sizeof(*attr)); | |
5887 | ||
5888 | ret = get_user(size, &uattr->size); | |
5889 | if (ret) | |
5890 | return ret; | |
5891 | ||
5892 | if (size > PAGE_SIZE) /* silly large */ | |
5893 | goto err_size; | |
5894 | ||
5895 | if (!size) /* abi compat */ | |
5896 | size = PERF_ATTR_SIZE_VER0; | |
5897 | ||
5898 | if (size < PERF_ATTR_SIZE_VER0) | |
5899 | goto err_size; | |
5900 | ||
5901 | /* | |
5902 | * If we're handed a bigger struct than we know of, | |
5903 | * ensure all the unknown bits are 0 - i.e. new | |
5904 | * user-space does not rely on any kernel feature | |
5905 | * extensions we dont know about yet. | |
5906 | */ | |
5907 | if (size > sizeof(*attr)) { | |
5908 | unsigned char __user *addr; | |
5909 | unsigned char __user *end; | |
5910 | unsigned char val; | |
5911 | ||
5912 | addr = (void __user *)uattr + sizeof(*attr); | |
5913 | end = (void __user *)uattr + size; | |
5914 | ||
5915 | for (; addr < end; addr++) { | |
5916 | ret = get_user(val, addr); | |
5917 | if (ret) | |
5918 | return ret; | |
5919 | if (val) | |
5920 | goto err_size; | |
5921 | } | |
5922 | size = sizeof(*attr); | |
5923 | } | |
5924 | ||
5925 | ret = copy_from_user(attr, uattr, size); | |
5926 | if (ret) | |
5927 | return -EFAULT; | |
5928 | ||
5929 | if (attr->__reserved_1) | |
5930 | return -EINVAL; | |
5931 | ||
5932 | if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) | |
5933 | return -EINVAL; | |
5934 | ||
5935 | if (attr->read_format & ~(PERF_FORMAT_MAX-1)) | |
5936 | return -EINVAL; | |
5937 | ||
5938 | out: | |
5939 | return ret; | |
5940 | ||
5941 | err_size: | |
5942 | put_user(sizeof(*attr), &uattr->size); | |
5943 | ret = -E2BIG; | |
5944 | goto out; | |
5945 | } | |
5946 | ||
5947 | static int | |
5948 | perf_event_set_output(struct perf_event *event, struct perf_event *output_event) | |
5949 | { | |
5950 | struct ring_buffer *rb = NULL, *old_rb = NULL; | |
5951 | int ret = -EINVAL; | |
5952 | ||
5953 | if (!output_event) | |
5954 | goto set; | |
5955 | ||
5956 | /* don't allow circular references */ | |
5957 | if (event == output_event) | |
5958 | goto out; | |
5959 | ||
5960 | /* | |
5961 | * Don't allow cross-cpu buffers | |
5962 | */ | |
5963 | if (output_event->cpu != event->cpu) | |
5964 | goto out; | |
5965 | ||
5966 | /* | |
5967 | * If its not a per-cpu rb, it must be the same task. | |
5968 | */ | |
5969 | if (output_event->cpu == -1 && output_event->ctx != event->ctx) | |
5970 | goto out; | |
5971 | ||
5972 | set: | |
5973 | mutex_lock(&event->mmap_mutex); | |
5974 | /* Can't redirect output if we've got an active mmap() */ | |
5975 | if (atomic_read(&event->mmap_count)) | |
5976 | goto unlock; | |
5977 | ||
5978 | if (output_event) { | |
5979 | /* get the rb we want to redirect to */ | |
5980 | rb = ring_buffer_get(output_event); | |
5981 | if (!rb) | |
5982 | goto unlock; | |
5983 | } | |
5984 | ||
5985 | old_rb = event->rb; | |
5986 | rcu_assign_pointer(event->rb, rb); | |
5987 | if (old_rb) | |
5988 | ring_buffer_detach(event, old_rb); | |
5989 | ret = 0; | |
5990 | unlock: | |
5991 | mutex_unlock(&event->mmap_mutex); | |
5992 | ||
5993 | if (old_rb) | |
5994 | ring_buffer_put(old_rb); | |
5995 | out: | |
5996 | return ret; | |
5997 | } | |
5998 | ||
5999 | /** | |
6000 | * sys_perf_event_open - open a performance event, associate it to a task/cpu | |
6001 | * | |
6002 | * @attr_uptr: event_id type attributes for monitoring/sampling | |
6003 | * @pid: target pid | |
6004 | * @cpu: target cpu | |
6005 | * @group_fd: group leader event fd | |
6006 | */ | |
6007 | SYSCALL_DEFINE5(perf_event_open, | |
6008 | struct perf_event_attr __user *, attr_uptr, | |
6009 | pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) | |
6010 | { | |
6011 | struct perf_event *group_leader = NULL, *output_event = NULL; | |
6012 | struct perf_event *event, *sibling; | |
6013 | struct perf_event_attr attr; | |
6014 | struct perf_event_context *ctx; | |
6015 | struct file *event_file = NULL; | |
6016 | struct file *group_file = NULL; | |
6017 | struct task_struct *task = NULL; | |
6018 | struct pmu *pmu; | |
6019 | int event_fd; | |
6020 | int move_group = 0; | |
6021 | int fput_needed = 0; | |
6022 | int err; | |
6023 | ||
6024 | /* for future expandability... */ | |
6025 | if (flags & ~PERF_FLAG_ALL) | |
6026 | return -EINVAL; | |
6027 | ||
6028 | err = perf_copy_attr(attr_uptr, &attr); | |
6029 | if (err) | |
6030 | return err; | |
6031 | ||
6032 | if (!attr.exclude_kernel) { | |
6033 | if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) | |
6034 | return -EACCES; | |
6035 | } | |
6036 | ||
6037 | if (attr.freq) { | |
6038 | if (attr.sample_freq > sysctl_perf_event_sample_rate) | |
6039 | return -EINVAL; | |
6040 | } | |
6041 | ||
6042 | /* | |
6043 | * In cgroup mode, the pid argument is used to pass the fd | |
6044 | * opened to the cgroup directory in cgroupfs. The cpu argument | |
6045 | * designates the cpu on which to monitor threads from that | |
6046 | * cgroup. | |
6047 | */ | |
6048 | if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) | |
6049 | return -EINVAL; | |
6050 | ||
6051 | event_fd = get_unused_fd_flags(O_RDWR); | |
6052 | if (event_fd < 0) | |
6053 | return event_fd; | |
6054 | ||
6055 | if (group_fd != -1) { | |
6056 | group_leader = perf_fget_light(group_fd, &fput_needed); | |
6057 | if (IS_ERR(group_leader)) { | |
6058 | err = PTR_ERR(group_leader); | |
6059 | goto err_fd; | |
6060 | } | |
6061 | group_file = group_leader->filp; | |
6062 | if (flags & PERF_FLAG_FD_OUTPUT) | |
6063 | output_event = group_leader; | |
6064 | if (flags & PERF_FLAG_FD_NO_GROUP) | |
6065 | group_leader = NULL; | |
6066 | } | |
6067 | ||
6068 | if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { | |
6069 | task = find_lively_task_by_vpid(pid); | |
6070 | if (IS_ERR(task)) { | |
6071 | err = PTR_ERR(task); | |
6072 | goto err_group_fd; | |
6073 | } | |
6074 | } | |
6075 | ||
6076 | event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, | |
6077 | NULL, NULL); | |
6078 | if (IS_ERR(event)) { | |
6079 | err = PTR_ERR(event); | |
6080 | goto err_task; | |
6081 | } | |
6082 | ||
6083 | if (flags & PERF_FLAG_PID_CGROUP) { | |
6084 | err = perf_cgroup_connect(pid, event, &attr, group_leader); | |
6085 | if (err) | |
6086 | goto err_alloc; | |
6087 | /* | |
6088 | * one more event: | |
6089 | * - that has cgroup constraint on event->cpu | |
6090 | * - that may need work on context switch | |
6091 | */ | |
6092 | atomic_inc(&per_cpu(perf_cgroup_events, event->cpu)); | |
6093 | static_key_slow_inc(&perf_sched_events.key); | |
6094 | } | |
6095 | ||
6096 | /* | |
6097 | * Special case software events and allow them to be part of | |
6098 | * any hardware group. | |
6099 | */ | |
6100 | pmu = event->pmu; | |
6101 | ||
6102 | if (group_leader && | |
6103 | (is_software_event(event) != is_software_event(group_leader))) { | |
6104 | if (is_software_event(event)) { | |
6105 | /* | |
6106 | * If event and group_leader are not both a software | |
6107 | * event, and event is, then group leader is not. | |
6108 | * | |
6109 | * Allow the addition of software events to !software | |
6110 | * groups, this is safe because software events never | |
6111 | * fail to schedule. | |
6112 | */ | |
6113 | pmu = group_leader->pmu; | |
6114 | } else if (is_software_event(group_leader) && | |
6115 | (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { | |
6116 | /* | |
6117 | * In case the group is a pure software group, and we | |
6118 | * try to add a hardware event, move the whole group to | |
6119 | * the hardware context. | |
6120 | */ | |
6121 | move_group = 1; | |
6122 | } | |
6123 | } | |
6124 | ||
6125 | /* | |
6126 | * Get the target context (task or percpu): | |
6127 | */ | |
6128 | ctx = find_get_context(pmu, task, cpu); | |
6129 | if (IS_ERR(ctx)) { | |
6130 | err = PTR_ERR(ctx); | |
6131 | goto err_alloc; | |
6132 | } | |
6133 | ||
6134 | if (task) { | |
6135 | put_task_struct(task); | |
6136 | task = NULL; | |
6137 | } | |
6138 | ||
6139 | /* | |
6140 | * Look up the group leader (we will attach this event to it): | |
6141 | */ | |
6142 | if (group_leader) { | |
6143 | err = -EINVAL; | |
6144 | ||
6145 | /* | |
6146 | * Do not allow a recursive hierarchy (this new sibling | |
6147 | * becoming part of another group-sibling): | |
6148 | */ | |
6149 | if (group_leader->group_leader != group_leader) | |
6150 | goto err_context; | |
6151 | /* | |
6152 | * Do not allow to attach to a group in a different | |
6153 | * task or CPU context: | |
6154 | */ | |
6155 | if (move_group) { | |
6156 | if (group_leader->ctx->type != ctx->type) | |
6157 | goto err_context; | |
6158 | } else { | |
6159 | if (group_leader->ctx != ctx) | |
6160 | goto err_context; | |
6161 | } | |
6162 | ||
6163 | /* | |
6164 | * Only a group leader can be exclusive or pinned | |
6165 | */ | |
6166 | if (attr.exclusive || attr.pinned) | |
6167 | goto err_context; | |
6168 | } | |
6169 | ||
6170 | if (output_event) { | |
6171 | err = perf_event_set_output(event, output_event); | |
6172 | if (err) | |
6173 | goto err_context; | |
6174 | } | |
6175 | ||
6176 | event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR); | |
6177 | if (IS_ERR(event_file)) { | |
6178 | err = PTR_ERR(event_file); | |
6179 | goto err_context; | |
6180 | } | |
6181 | ||
6182 | if (move_group) { | |
6183 | struct perf_event_context *gctx = group_leader->ctx; | |
6184 | ||
6185 | mutex_lock(&gctx->mutex); | |
6186 | perf_remove_from_context(group_leader); | |
6187 | list_for_each_entry(sibling, &group_leader->sibling_list, | |
6188 | group_entry) { | |
6189 | perf_remove_from_context(sibling); | |
6190 | put_ctx(gctx); | |
6191 | } | |
6192 | mutex_unlock(&gctx->mutex); | |
6193 | put_ctx(gctx); | |
6194 | } | |
6195 | ||
6196 | event->filp = event_file; | |
6197 | WARN_ON_ONCE(ctx->parent_ctx); | |
6198 | mutex_lock(&ctx->mutex); | |
6199 | ||
6200 | if (move_group) { | |
6201 | perf_install_in_context(ctx, group_leader, cpu); | |
6202 | get_ctx(ctx); | |
6203 | list_for_each_entry(sibling, &group_leader->sibling_list, | |
6204 | group_entry) { | |
6205 | perf_install_in_context(ctx, sibling, cpu); | |
6206 | get_ctx(ctx); | |
6207 | } | |
6208 | } | |
6209 | ||
6210 | perf_install_in_context(ctx, event, cpu); | |
6211 | ++ctx->generation; | |
6212 | perf_unpin_context(ctx); | |
6213 | mutex_unlock(&ctx->mutex); | |
6214 | ||
6215 | event->owner = current; | |
6216 | ||
6217 | mutex_lock(¤t->perf_event_mutex); | |
6218 | list_add_tail(&event->owner_entry, ¤t->perf_event_list); | |
6219 | mutex_unlock(¤t->perf_event_mutex); | |
6220 | ||
6221 | /* | |
6222 | * Precalculate sample_data sizes | |
6223 | */ | |
6224 | perf_event__header_size(event); | |
6225 | perf_event__id_header_size(event); | |
6226 | ||
6227 | /* | |
6228 | * Drop the reference on the group_event after placing the | |
6229 | * new event on the sibling_list. This ensures destruction | |
6230 | * of the group leader will find the pointer to itself in | |
6231 | * perf_group_detach(). | |
6232 | */ | |
6233 | fput_light(group_file, fput_needed); | |
6234 | fd_install(event_fd, event_file); | |
6235 | return event_fd; | |
6236 | ||
6237 | err_context: | |
6238 | perf_unpin_context(ctx); | |
6239 | put_ctx(ctx); | |
6240 | err_alloc: | |
6241 | free_event(event); | |
6242 | err_task: | |
6243 | if (task) | |
6244 | put_task_struct(task); | |
6245 | err_group_fd: | |
6246 | fput_light(group_file, fput_needed); | |
6247 | err_fd: | |
6248 | put_unused_fd(event_fd); | |
6249 | return err; | |
6250 | } | |
6251 | ||
6252 | /** | |
6253 | * perf_event_create_kernel_counter | |
6254 | * | |
6255 | * @attr: attributes of the counter to create | |
6256 | * @cpu: cpu in which the counter is bound | |
6257 | * @task: task to profile (NULL for percpu) | |
6258 | */ | |
6259 | struct perf_event * | |
6260 | perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, | |
6261 | struct task_struct *task, | |
6262 | perf_overflow_handler_t overflow_handler, | |
6263 | void *context) | |
6264 | { | |
6265 | struct perf_event_context *ctx; | |
6266 | struct perf_event *event; | |
6267 | int err; | |
6268 | ||
6269 | /* | |
6270 | * Get the target context (task or percpu): | |
6271 | */ | |
6272 | ||
6273 | event = perf_event_alloc(attr, cpu, task, NULL, NULL, | |
6274 | overflow_handler, context); | |
6275 | if (IS_ERR(event)) { | |
6276 | err = PTR_ERR(event); | |
6277 | goto err; | |
6278 | } | |
6279 | ||
6280 | ctx = find_get_context(event->pmu, task, cpu); | |
6281 | if (IS_ERR(ctx)) { | |
6282 | err = PTR_ERR(ctx); | |
6283 | goto err_free; | |
6284 | } | |
6285 | ||
6286 | event->filp = NULL; | |
6287 | WARN_ON_ONCE(ctx->parent_ctx); | |
6288 | mutex_lock(&ctx->mutex); | |
6289 | perf_install_in_context(ctx, event, cpu); | |
6290 | ++ctx->generation; | |
6291 | perf_unpin_context(ctx); | |
6292 | mutex_unlock(&ctx->mutex); | |
6293 | ||
6294 | return event; | |
6295 | ||
6296 | err_free: | |
6297 | free_event(event); | |
6298 | err: | |
6299 | return ERR_PTR(err); | |
6300 | } | |
6301 | EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); | |
6302 | ||
6303 | static void sync_child_event(struct perf_event *child_event, | |
6304 | struct task_struct *child) | |
6305 | { | |
6306 | struct perf_event *parent_event = child_event->parent; | |
6307 | u64 child_val; | |
6308 | ||
6309 | if (child_event->attr.inherit_stat) | |
6310 | perf_event_read_event(child_event, child); | |
6311 | ||
6312 | child_val = perf_event_count(child_event); | |
6313 | ||
6314 | /* | |
6315 | * Add back the child's count to the parent's count: | |
6316 | */ | |
6317 | atomic64_add(child_val, &parent_event->child_count); | |
6318 | atomic64_add(child_event->total_time_enabled, | |
6319 | &parent_event->child_total_time_enabled); | |
6320 | atomic64_add(child_event->total_time_running, | |
6321 | &parent_event->child_total_time_running); | |
6322 | ||
6323 | /* | |
6324 | * Remove this event from the parent's list | |
6325 | */ | |
6326 | WARN_ON_ONCE(parent_event->ctx->parent_ctx); | |
6327 | mutex_lock(&parent_event->child_mutex); | |
6328 | list_del_init(&child_event->child_list); | |
6329 | mutex_unlock(&parent_event->child_mutex); | |
6330 | ||
6331 | /* | |
6332 | * Release the parent event, if this was the last | |
6333 | * reference to it. | |
6334 | */ | |
6335 | fput(parent_event->filp); | |
6336 | } | |
6337 | ||
6338 | static void | |
6339 | __perf_event_exit_task(struct perf_event *child_event, | |
6340 | struct perf_event_context *child_ctx, | |
6341 | struct task_struct *child) | |
6342 | { | |
6343 | if (child_event->parent) { | |
6344 | raw_spin_lock_irq(&child_ctx->lock); | |
6345 | perf_group_detach(child_event); | |
6346 | raw_spin_unlock_irq(&child_ctx->lock); | |
6347 | } | |
6348 | ||
6349 | perf_remove_from_context(child_event); | |
6350 | ||
6351 | /* | |
6352 | * It can happen that the parent exits first, and has events | |
6353 | * that are still around due to the child reference. These | |
6354 | * events need to be zapped. | |
6355 | */ | |
6356 | if (child_event->parent) { | |
6357 | sync_child_event(child_event, child); | |
6358 | free_event(child_event); | |
6359 | } | |
6360 | } | |
6361 | ||
6362 | static void perf_event_exit_task_context(struct task_struct *child, int ctxn) | |
6363 | { | |
6364 | struct perf_event *child_event, *tmp; | |
6365 | struct perf_event_context *child_ctx; | |
6366 | unsigned long flags; | |
6367 | ||
6368 | if (likely(!child->perf_event_ctxp[ctxn])) { | |
6369 | perf_event_task(child, NULL, 0); | |
6370 | return; | |
6371 | } | |
6372 | ||
6373 | local_irq_save(flags); | |
6374 | /* | |
6375 | * We can't reschedule here because interrupts are disabled, | |
6376 | * and either child is current or it is a task that can't be | |
6377 | * scheduled, so we are now safe from rescheduling changing | |
6378 | * our context. | |
6379 | */ | |
6380 | child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]); | |
6381 | ||
6382 | /* | |
6383 | * Take the context lock here so that if find_get_context is | |
6384 | * reading child->perf_event_ctxp, we wait until it has | |
6385 | * incremented the context's refcount before we do put_ctx below. | |
6386 | */ | |
6387 | raw_spin_lock(&child_ctx->lock); | |
6388 | task_ctx_sched_out(child_ctx); | |
6389 | child->perf_event_ctxp[ctxn] = NULL; | |
6390 | /* | |
6391 | * If this context is a clone; unclone it so it can't get | |
6392 | * swapped to another process while we're removing all | |
6393 | * the events from it. | |
6394 | */ | |
6395 | unclone_ctx(child_ctx); | |
6396 | update_context_time(child_ctx); | |
6397 | raw_spin_unlock_irqrestore(&child_ctx->lock, flags); | |
6398 | ||
6399 | /* | |
6400 | * Report the task dead after unscheduling the events so that we | |
6401 | * won't get any samples after PERF_RECORD_EXIT. We can however still | |
6402 | * get a few PERF_RECORD_READ events. | |
6403 | */ | |
6404 | perf_event_task(child, child_ctx, 0); | |
6405 | ||
6406 | /* | |
6407 | * We can recurse on the same lock type through: | |
6408 | * | |
6409 | * __perf_event_exit_task() | |
6410 | * sync_child_event() | |
6411 | * fput(parent_event->filp) | |
6412 | * perf_release() | |
6413 | * mutex_lock(&ctx->mutex) | |
6414 | * | |
6415 | * But since its the parent context it won't be the same instance. | |
6416 | */ | |
6417 | mutex_lock(&child_ctx->mutex); | |
6418 | ||
6419 | again: | |
6420 | list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups, | |
6421 | group_entry) | |
6422 | __perf_event_exit_task(child_event, child_ctx, child); | |
6423 | ||
6424 | list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups, | |
6425 | group_entry) | |
6426 | __perf_event_exit_task(child_event, child_ctx, child); | |
6427 | ||
6428 | /* | |
6429 | * If the last event was a group event, it will have appended all | |
6430 | * its siblings to the list, but we obtained 'tmp' before that which | |
6431 | * will still point to the list head terminating the iteration. | |
6432 | */ | |
6433 | if (!list_empty(&child_ctx->pinned_groups) || | |
6434 | !list_empty(&child_ctx->flexible_groups)) | |
6435 | goto again; | |
6436 | ||
6437 | mutex_unlock(&child_ctx->mutex); | |
6438 | ||
6439 | put_ctx(child_ctx); | |
6440 | } | |
6441 | ||
6442 | /* | |
6443 | * When a child task exits, feed back event values to parent events. | |
6444 | */ | |
6445 | void perf_event_exit_task(struct task_struct *child) | |
6446 | { | |
6447 | struct perf_event *event, *tmp; | |
6448 | int ctxn; | |
6449 | ||
6450 | mutex_lock(&child->perf_event_mutex); | |
6451 | list_for_each_entry_safe(event, tmp, &child->perf_event_list, | |
6452 | owner_entry) { | |
6453 | list_del_init(&event->owner_entry); | |
6454 | ||
6455 | /* | |
6456 | * Ensure the list deletion is visible before we clear | |
6457 | * the owner, closes a race against perf_release() where | |
6458 | * we need to serialize on the owner->perf_event_mutex. | |
6459 | */ | |
6460 | smp_wmb(); | |
6461 | event->owner = NULL; | |
6462 | } | |
6463 | mutex_unlock(&child->perf_event_mutex); | |
6464 | ||
6465 | for_each_task_context_nr(ctxn) | |
6466 | perf_event_exit_task_context(child, ctxn); | |
6467 | } | |
6468 | ||
6469 | static void perf_free_event(struct perf_event *event, | |
6470 | struct perf_event_context *ctx) | |
6471 | { | |
6472 | struct perf_event *parent = event->parent; | |
6473 | ||
6474 | if (WARN_ON_ONCE(!parent)) | |
6475 | return; | |
6476 | ||
6477 | mutex_lock(&parent->child_mutex); | |
6478 | list_del_init(&event->child_list); | |
6479 | mutex_unlock(&parent->child_mutex); | |
6480 | ||
6481 | fput(parent->filp); | |
6482 | ||
6483 | perf_group_detach(event); | |
6484 | list_del_event(event, ctx); | |
6485 | free_event(event); | |
6486 | } | |
6487 | ||
6488 | /* | |
6489 | * free an unexposed, unused context as created by inheritance by | |
6490 | * perf_event_init_task below, used by fork() in case of fail. | |
6491 | */ | |
6492 | void perf_event_free_task(struct task_struct *task) | |
6493 | { | |
6494 | struct perf_event_context *ctx; | |
6495 | struct perf_event *event, *tmp; | |
6496 | int ctxn; | |
6497 | ||
6498 | for_each_task_context_nr(ctxn) { | |
6499 | ctx = task->perf_event_ctxp[ctxn]; | |
6500 | if (!ctx) | |
6501 | continue; | |
6502 | ||
6503 | mutex_lock(&ctx->mutex); | |
6504 | again: | |
6505 | list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, | |
6506 | group_entry) | |
6507 | perf_free_event(event, ctx); | |
6508 | ||
6509 | list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, | |
6510 | group_entry) | |
6511 | perf_free_event(event, ctx); | |
6512 | ||
6513 | if (!list_empty(&ctx->pinned_groups) || | |
6514 | !list_empty(&ctx->flexible_groups)) | |
6515 | goto again; | |
6516 | ||
6517 | mutex_unlock(&ctx->mutex); | |
6518 | ||
6519 | put_ctx(ctx); | |
6520 | } | |
6521 | } | |
6522 | ||
6523 | void perf_event_delayed_put(struct task_struct *task) | |
6524 | { | |
6525 | int ctxn; | |
6526 | ||
6527 | for_each_task_context_nr(ctxn) | |
6528 | WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); | |
6529 | } | |
6530 | ||
6531 | /* | |
6532 | * inherit a event from parent task to child task: | |
6533 | */ | |
6534 | static struct perf_event * | |
6535 | inherit_event(struct perf_event *parent_event, | |
6536 | struct task_struct *parent, | |
6537 | struct perf_event_context *parent_ctx, | |
6538 | struct task_struct *child, | |
6539 | struct perf_event *group_leader, | |
6540 | struct perf_event_context *child_ctx) | |
6541 | { | |
6542 | struct perf_event *child_event; | |
6543 | unsigned long flags; | |
6544 | ||
6545 | /* | |
6546 | * Instead of creating recursive hierarchies of events, | |
6547 | * we link inherited events back to the original parent, | |
6548 | * which has a filp for sure, which we use as the reference | |
6549 | * count: | |
6550 | */ | |
6551 | if (parent_event->parent) | |
6552 | parent_event = parent_event->parent; | |
6553 | ||
6554 | child_event = perf_event_alloc(&parent_event->attr, | |
6555 | parent_event->cpu, | |
6556 | child, | |
6557 | group_leader, parent_event, | |
6558 | NULL, NULL); | |
6559 | if (IS_ERR(child_event)) | |
6560 | return child_event; | |
6561 | get_ctx(child_ctx); | |
6562 | ||
6563 | /* | |
6564 | * Make the child state follow the state of the parent event, | |
6565 | * not its attr.disabled bit. We hold the parent's mutex, | |
6566 | * so we won't race with perf_event_{en, dis}able_family. | |
6567 | */ | |
6568 | if (parent_event->state >= PERF_EVENT_STATE_INACTIVE) | |
6569 | child_event->state = PERF_EVENT_STATE_INACTIVE; | |
6570 | else | |
6571 | child_event->state = PERF_EVENT_STATE_OFF; | |
6572 | ||
6573 | if (parent_event->attr.freq) { | |
6574 | u64 sample_period = parent_event->hw.sample_period; | |
6575 | struct hw_perf_event *hwc = &child_event->hw; | |
6576 | ||
6577 | hwc->sample_period = sample_period; | |
6578 | hwc->last_period = sample_period; | |
6579 | ||
6580 | local64_set(&hwc->period_left, sample_period); | |
6581 | } | |
6582 | ||
6583 | child_event->ctx = child_ctx; | |
6584 | child_event->overflow_handler = parent_event->overflow_handler; | |
6585 | child_event->overflow_handler_context | |
6586 | = parent_event->overflow_handler_context; | |
6587 | ||
6588 | /* | |
6589 | * Precalculate sample_data sizes | |
6590 | */ | |
6591 | perf_event__header_size(child_event); | |
6592 | perf_event__id_header_size(child_event); | |
6593 | ||
6594 | /* | |
6595 | * Link it up in the child's context: | |
6596 | */ | |
6597 | raw_spin_lock_irqsave(&child_ctx->lock, flags); | |
6598 | add_event_to_ctx(child_event, child_ctx); | |
6599 | raw_spin_unlock_irqrestore(&child_ctx->lock, flags); | |
6600 | ||
6601 | /* | |
6602 | * Get a reference to the parent filp - we will fput it | |
6603 | * when the child event exits. This is safe to do because | |
6604 | * we are in the parent and we know that the filp still | |
6605 | * exists and has a nonzero count: | |
6606 | */ | |
6607 | atomic_long_inc(&parent_event->filp->f_count); | |
6608 | ||
6609 | /* | |
6610 | * Link this into the parent event's child list | |
6611 | */ | |
6612 | WARN_ON_ONCE(parent_event->ctx->parent_ctx); | |
6613 | mutex_lock(&parent_event->child_mutex); | |
6614 | list_add_tail(&child_event->child_list, &parent_event->child_list); | |
6615 | mutex_unlock(&parent_event->child_mutex); | |
6616 | ||
6617 | return child_event; | |
6618 | } | |
6619 | ||
6620 | static int inherit_group(struct perf_event *parent_event, | |
6621 | struct task_struct *parent, | |
6622 | struct perf_event_context *parent_ctx, | |
6623 | struct task_struct *child, | |
6624 | struct perf_event_context *child_ctx) | |
6625 | { | |
6626 | struct perf_event *leader; | |
6627 | struct perf_event *sub; | |
6628 | struct perf_event *child_ctr; | |
6629 | ||
6630 | leader = inherit_event(parent_event, parent, parent_ctx, | |
6631 | child, NULL, child_ctx); | |
6632 | if (IS_ERR(leader)) | |
6633 | return PTR_ERR(leader); | |
6634 | list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { | |
6635 | child_ctr = inherit_event(sub, parent, parent_ctx, | |
6636 | child, leader, child_ctx); | |
6637 | if (IS_ERR(child_ctr)) | |
6638 | return PTR_ERR(child_ctr); | |
6639 | } | |
6640 | return 0; | |
6641 | } | |
6642 | ||
6643 | static int | |
6644 | inherit_task_group(struct perf_event *event, struct task_struct *parent, | |
6645 | struct perf_event_context *parent_ctx, | |
6646 | struct task_struct *child, int ctxn, | |
6647 | int *inherited_all) | |
6648 | { | |
6649 | int ret; | |
6650 | struct perf_event_context *child_ctx; | |
6651 | ||
6652 | if (!event->attr.inherit) { | |
6653 | *inherited_all = 0; | |
6654 | return 0; | |
6655 | } | |
6656 | ||
6657 | child_ctx = child->perf_event_ctxp[ctxn]; | |
6658 | if (!child_ctx) { | |
6659 | /* | |
6660 | * This is executed from the parent task context, so | |
6661 | * inherit events that have been marked for cloning. | |
6662 | * First allocate and initialize a context for the | |
6663 | * child. | |
6664 | */ | |
6665 | ||
6666 | child_ctx = alloc_perf_context(event->pmu, child); | |
6667 | if (!child_ctx) | |
6668 | return -ENOMEM; | |
6669 | ||
6670 | child->perf_event_ctxp[ctxn] = child_ctx; | |
6671 | } | |
6672 | ||
6673 | ret = inherit_group(event, parent, parent_ctx, | |
6674 | child, child_ctx); | |
6675 | ||
6676 | if (ret) | |
6677 | *inherited_all = 0; | |
6678 | ||
6679 | return ret; | |
6680 | } | |
6681 | ||
6682 | /* | |
6683 | * Initialize the perf_event context in task_struct | |
6684 | */ | |
6685 | int perf_event_init_context(struct task_struct *child, int ctxn) | |
6686 | { | |
6687 | struct perf_event_context *child_ctx, *parent_ctx; | |
6688 | struct perf_event_context *cloned_ctx; | |
6689 | struct perf_event *event; | |
6690 | struct task_struct *parent = current; | |
6691 | int inherited_all = 1; | |
6692 | unsigned long flags; | |
6693 | int ret = 0; | |
6694 | ||
6695 | if (likely(!parent->perf_event_ctxp[ctxn])) | |
6696 | return 0; | |
6697 | ||
6698 | /* | |
6699 | * If the parent's context is a clone, pin it so it won't get | |
6700 | * swapped under us. | |
6701 | */ | |
6702 | parent_ctx = perf_pin_task_context(parent, ctxn); | |
6703 | ||
6704 | /* | |
6705 | * No need to check if parent_ctx != NULL here; since we saw | |
6706 | * it non-NULL earlier, the only reason for it to become NULL | |
6707 | * is if we exit, and since we're currently in the middle of | |
6708 | * a fork we can't be exiting at the same time. | |
6709 | */ | |
6710 | ||
6711 | /* | |
6712 | * Lock the parent list. No need to lock the child - not PID | |
6713 | * hashed yet and not running, so nobody can access it. | |
6714 | */ | |
6715 | mutex_lock(&parent_ctx->mutex); | |
6716 | ||
6717 | /* | |
6718 | * We dont have to disable NMIs - we are only looking at | |
6719 | * the list, not manipulating it: | |
6720 | */ | |
6721 | list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { | |
6722 | ret = inherit_task_group(event, parent, parent_ctx, | |
6723 | child, ctxn, &inherited_all); | |
6724 | if (ret) | |
6725 | break; | |
6726 | } | |
6727 | ||
6728 | /* | |
6729 | * We can't hold ctx->lock when iterating the ->flexible_group list due | |
6730 | * to allocations, but we need to prevent rotation because | |
6731 | * rotate_ctx() will change the list from interrupt context. | |
6732 | */ | |
6733 | raw_spin_lock_irqsave(&parent_ctx->lock, flags); | |
6734 | parent_ctx->rotate_disable = 1; | |
6735 | raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); | |
6736 | ||
6737 | list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { | |
6738 | ret = inherit_task_group(event, parent, parent_ctx, | |
6739 | child, ctxn, &inherited_all); | |
6740 | if (ret) | |
6741 | break; | |
6742 | } | |
6743 | ||
6744 | raw_spin_lock_irqsave(&parent_ctx->lock, flags); | |
6745 | parent_ctx->rotate_disable = 0; | |
6746 | ||
6747 | child_ctx = child->perf_event_ctxp[ctxn]; | |
6748 | ||
6749 | if (child_ctx && inherited_all) { | |
6750 | /* | |
6751 | * Mark the child context as a clone of the parent | |
6752 | * context, or of whatever the parent is a clone of. | |
6753 | * | |
6754 | * Note that if the parent is a clone, the holding of | |
6755 | * parent_ctx->lock avoids it from being uncloned. | |
6756 | */ | |
6757 | cloned_ctx = parent_ctx->parent_ctx; | |
6758 | if (cloned_ctx) { | |
6759 | child_ctx->parent_ctx = cloned_ctx; | |
6760 | child_ctx->parent_gen = parent_ctx->parent_gen; | |
6761 | } else { | |
6762 | child_ctx->parent_ctx = parent_ctx; | |
6763 | child_ctx->parent_gen = parent_ctx->generation; | |
6764 | } | |
6765 | get_ctx(child_ctx->parent_ctx); | |
6766 | } | |
6767 | ||
6768 | raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); | |
6769 | mutex_unlock(&parent_ctx->mutex); | |
6770 | ||
6771 | perf_unpin_context(parent_ctx); | |
6772 | put_ctx(parent_ctx); | |
6773 | ||
6774 | return ret; | |
6775 | } | |
6776 | ||
6777 | /* | |
6778 | * Initialize the perf_event context in task_struct | |
6779 | */ | |
6780 | int perf_event_init_task(struct task_struct *child) | |
6781 | { | |
6782 | int ctxn, ret; | |
6783 | ||
6784 | memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); | |
6785 | mutex_init(&child->perf_event_mutex); | |
6786 | INIT_LIST_HEAD(&child->perf_event_list); | |
6787 | ||
6788 | for_each_task_context_nr(ctxn) { | |
6789 | ret = perf_event_init_context(child, ctxn); | |
6790 | if (ret) | |
6791 | return ret; | |
6792 | } | |
6793 | ||
6794 | return 0; | |
6795 | } | |
6796 | ||
6797 | static void __init perf_event_init_all_cpus(void) | |
6798 | { | |
6799 | struct swevent_htable *swhash; | |
6800 | int cpu; | |
6801 | ||
6802 | for_each_possible_cpu(cpu) { | |
6803 | swhash = &per_cpu(swevent_htable, cpu); | |
6804 | mutex_init(&swhash->hlist_mutex); | |
6805 | INIT_LIST_HEAD(&per_cpu(rotation_list, cpu)); | |
6806 | } | |
6807 | } | |
6808 | ||
6809 | static void __cpuinit perf_event_init_cpu(int cpu) | |
6810 | { | |
6811 | struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); | |
6812 | ||
6813 | mutex_lock(&swhash->hlist_mutex); | |
6814 | if (swhash->hlist_refcount > 0) { | |
6815 | struct swevent_hlist *hlist; | |
6816 | ||
6817 | hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); | |
6818 | WARN_ON(!hlist); | |
6819 | rcu_assign_pointer(swhash->swevent_hlist, hlist); | |
6820 | } | |
6821 | mutex_unlock(&swhash->hlist_mutex); | |
6822 | } | |
6823 | ||
6824 | #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC | |
6825 | static void perf_pmu_rotate_stop(struct pmu *pmu) | |
6826 | { | |
6827 | struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); | |
6828 | ||
6829 | WARN_ON(!irqs_disabled()); | |
6830 | ||
6831 | list_del_init(&cpuctx->rotation_list); | |
6832 | } | |
6833 | ||
6834 | static void __perf_event_exit_context(void *__info) | |
6835 | { | |
6836 | struct perf_event_context *ctx = __info; | |
6837 | struct perf_event *event, *tmp; | |
6838 | ||
6839 | perf_pmu_rotate_stop(ctx->pmu); | |
6840 | ||
6841 | list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) | |
6842 | __perf_remove_from_context(event); | |
6843 | list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) | |
6844 | __perf_remove_from_context(event); | |
6845 | } | |
6846 | ||
6847 | static void perf_event_exit_cpu_context(int cpu) | |
6848 | { | |
6849 | struct perf_event_context *ctx; | |
6850 | struct pmu *pmu; | |
6851 | int idx; | |
6852 | ||
6853 | idx = srcu_read_lock(&pmus_srcu); | |
6854 | list_for_each_entry_rcu(pmu, &pmus, entry) { | |
6855 | ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; | |
6856 | ||
6857 | mutex_lock(&ctx->mutex); | |
6858 | smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); | |
6859 | mutex_unlock(&ctx->mutex); | |
6860 | } | |
6861 | srcu_read_unlock(&pmus_srcu, idx); | |
6862 | } | |
6863 | ||
6864 | static void perf_event_exit_cpu(int cpu) | |
6865 | { | |
6866 | struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); | |
6867 | ||
6868 | mutex_lock(&swhash->hlist_mutex); | |
6869 | swevent_hlist_release(swhash); | |
6870 | mutex_unlock(&swhash->hlist_mutex); | |
6871 | ||
6872 | perf_event_exit_cpu_context(cpu); | |
6873 | } | |
6874 | #else | |
6875 | static inline void perf_event_exit_cpu(int cpu) { } | |
6876 | #endif | |
6877 | ||
6878 | static int | |
6879 | perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) | |
6880 | { | |
6881 | int cpu; | |
6882 | ||
6883 | for_each_online_cpu(cpu) | |
6884 | perf_event_exit_cpu(cpu); | |
6885 | ||
6886 | return NOTIFY_OK; | |
6887 | } | |
6888 | ||
6889 | /* | |
6890 | * Run the perf reboot notifier at the very last possible moment so that | |
6891 | * the generic watchdog code runs as long as possible. | |
6892 | */ | |
6893 | static struct notifier_block perf_reboot_notifier = { | |
6894 | .notifier_call = perf_reboot, | |
6895 | .priority = INT_MIN, | |
6896 | }; | |
6897 | ||
6898 | static int __cpuinit | |
6899 | perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) | |
6900 | { | |
6901 | unsigned int cpu = (long)hcpu; | |
6902 | ||
6903 | switch (action & ~CPU_TASKS_FROZEN) { | |
6904 | ||
6905 | case CPU_UP_PREPARE: | |
6906 | case CPU_DOWN_FAILED: | |
6907 | perf_event_init_cpu(cpu); | |
6908 | break; | |
6909 | ||
6910 | case CPU_UP_CANCELED: | |
6911 | case CPU_DOWN_PREPARE: | |
6912 | perf_event_exit_cpu(cpu); | |
6913 | break; | |
6914 | ||
6915 | default: | |
6916 | break; | |
6917 | } | |
6918 | ||
6919 | return NOTIFY_OK; | |
6920 | } | |
6921 | ||
6922 | void __init perf_event_init(void) | |
6923 | { | |
6924 | int ret; | |
6925 | ||
6926 | idr_init(&pmu_idr); | |
6927 | ||
6928 | perf_event_init_all_cpus(); | |
6929 | init_srcu_struct(&pmus_srcu); | |
6930 | perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); | |
6931 | perf_pmu_register(&perf_cpu_clock, NULL, -1); | |
6932 | perf_pmu_register(&perf_task_clock, NULL, -1); | |
6933 | perf_tp_register(); | |
6934 | perf_cpu_notifier(perf_cpu_notify); | |
6935 | register_reboot_notifier(&perf_reboot_notifier); | |
6936 | ||
6937 | ret = init_hw_breakpoint(); | |
6938 | WARN(ret, "hw_breakpoint initialization failed with: %d", ret); | |
6939 | ||
6940 | /* do not patch jump label more than once per second */ | |
6941 | jump_label_rate_limit(&perf_sched_events, HZ); | |
6942 | } | |
6943 | ||
6944 | static int __init perf_event_sysfs_init(void) | |
6945 | { | |
6946 | struct pmu *pmu; | |
6947 | int ret; | |
6948 | ||
6949 | mutex_lock(&pmus_lock); | |
6950 | ||
6951 | ret = bus_register(&pmu_bus); | |
6952 | if (ret) | |
6953 | goto unlock; | |
6954 | ||
6955 | list_for_each_entry(pmu, &pmus, entry) { | |
6956 | if (!pmu->name || pmu->type < 0) | |
6957 | continue; | |
6958 | ||
6959 | ret = pmu_dev_alloc(pmu); | |
6960 | WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); | |
6961 | } | |
6962 | pmu_bus_running = 1; | |
6963 | ret = 0; | |
6964 | ||
6965 | unlock: | |
6966 | mutex_unlock(&pmus_lock); | |
6967 | ||
6968 | return ret; | |
6969 | } | |
6970 | device_initcall(perf_event_sysfs_init); | |
6971 | ||
6972 | #ifdef CONFIG_CGROUP_PERF | |
6973 | static struct cgroup_subsys_state *perf_cgroup_create( | |
6974 | struct cgroup_subsys *ss, struct cgroup *cont) | |
6975 | { | |
6976 | struct perf_cgroup *jc; | |
6977 | ||
6978 | jc = kzalloc(sizeof(*jc), GFP_KERNEL); | |
6979 | if (!jc) | |
6980 | return ERR_PTR(-ENOMEM); | |
6981 | ||
6982 | jc->info = alloc_percpu(struct perf_cgroup_info); | |
6983 | if (!jc->info) { | |
6984 | kfree(jc); | |
6985 | return ERR_PTR(-ENOMEM); | |
6986 | } | |
6987 | ||
6988 | return &jc->css; | |
6989 | } | |
6990 | ||
6991 | static void perf_cgroup_destroy(struct cgroup_subsys *ss, | |
6992 | struct cgroup *cont) | |
6993 | { | |
6994 | struct perf_cgroup *jc; | |
6995 | jc = container_of(cgroup_subsys_state(cont, perf_subsys_id), | |
6996 | struct perf_cgroup, css); | |
6997 | free_percpu(jc->info); | |
6998 | kfree(jc); | |
6999 | } | |
7000 | ||
7001 | static int __perf_cgroup_move(void *info) | |
7002 | { | |
7003 | struct task_struct *task = info; | |
7004 | perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); | |
7005 | return 0; | |
7006 | } | |
7007 | ||
7008 | static void perf_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
7009 | struct cgroup_taskset *tset) | |
7010 | { | |
7011 | struct task_struct *task; | |
7012 | ||
7013 | cgroup_taskset_for_each(task, cgrp, tset) | |
7014 | task_function_call(task, __perf_cgroup_move, task); | |
7015 | } | |
7016 | ||
7017 | static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp, | |
7018 | struct cgroup *old_cgrp, struct task_struct *task) | |
7019 | { | |
7020 | /* | |
7021 | * cgroup_exit() is called in the copy_process() failure path. | |
7022 | * Ignore this case since the task hasn't ran yet, this avoids | |
7023 | * trying to poke a half freed task state from generic code. | |
7024 | */ | |
7025 | if (!(task->flags & PF_EXITING)) | |
7026 | return; | |
7027 | ||
7028 | task_function_call(task, __perf_cgroup_move, task); | |
7029 | } | |
7030 | ||
7031 | struct cgroup_subsys perf_subsys = { | |
7032 | .name = "perf_event", | |
7033 | .subsys_id = perf_subsys_id, | |
7034 | .create = perf_cgroup_create, | |
7035 | .destroy = perf_cgroup_destroy, | |
7036 | .exit = perf_cgroup_exit, | |
7037 | .attach = perf_cgroup_attach, | |
7038 | }; | |
7039 | #endif /* CONFIG_CGROUP_PERF */ |