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TOMOYO Linux Cross Reference
Linux/kernel/events/core.c

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  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/tick.h>
 22 #include <linux/sysfs.h>
 23 #include <linux/dcache.h>
 24 #include <linux/percpu.h>
 25 #include <linux/ptrace.h>
 26 #include <linux/reboot.h>
 27 #include <linux/vmstat.h>
 28 #include <linux/device.h>
 29 #include <linux/export.h>
 30 #include <linux/vmalloc.h>
 31 #include <linux/hardirq.h>
 32 #include <linux/rculist.h>
 33 #include <linux/uaccess.h>
 34 #include <linux/syscalls.h>
 35 #include <linux/anon_inodes.h>
 36 #include <linux/kernel_stat.h>
 37 #include <linux/perf_event.h>
 38 #include <linux/ftrace_event.h>
 39 #include <linux/hw_breakpoint.h>
 40 #include <linux/mm_types.h>
 41 #include <linux/cgroup.h>
 42 
 43 #include "internal.h"
 44 
 45 #include <asm/irq_regs.h>
 46 
 47 struct remote_function_call {
 48         struct task_struct      *p;
 49         int                     (*func)(void *info);
 50         void                    *info;
 51         int                     ret;
 52 };
 53 
 54 static void remote_function(void *data)
 55 {
 56         struct remote_function_call *tfc = data;
 57         struct task_struct *p = tfc->p;
 58 
 59         if (p) {
 60                 tfc->ret = -EAGAIN;
 61                 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
 62                         return;
 63         }
 64 
 65         tfc->ret = tfc->func(tfc->info);
 66 }
 67 
 68 /**
 69  * task_function_call - call a function on the cpu on which a task runs
 70  * @p:          the task to evaluate
 71  * @func:       the function to be called
 72  * @info:       the function call argument
 73  *
 74  * Calls the function @func when the task is currently running. This might
 75  * be on the current CPU, which just calls the function directly
 76  *
 77  * returns: @func return value, or
 78  *          -ESRCH  - when the process isn't running
 79  *          -EAGAIN - when the process moved away
 80  */
 81 static int
 82 task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
 83 {
 84         struct remote_function_call data = {
 85                 .p      = p,
 86                 .func   = func,
 87                 .info   = info,
 88                 .ret    = -ESRCH, /* No such (running) process */
 89         };
 90 
 91         if (task_curr(p))
 92                 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
 93 
 94         return data.ret;
 95 }
 96 
 97 /**
 98  * cpu_function_call - call a function on the cpu
 99  * @func:       the function to be called
100  * @info:       the function call argument
101  *
102  * Calls the function @func on the remote cpu.
103  *
104  * returns: @func return value or -ENXIO when the cpu is offline
105  */
106 static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
107 {
108         struct remote_function_call data = {
109                 .p      = NULL,
110                 .func   = func,
111                 .info   = info,
112                 .ret    = -ENXIO, /* No such CPU */
113         };
114 
115         smp_call_function_single(cpu, remote_function, &data, 1);
116 
117         return data.ret;
118 }
119 
120 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
121                        PERF_FLAG_FD_OUTPUT  |\
122                        PERF_FLAG_PID_CGROUP)
123 
124 /*
125  * branch priv levels that need permission checks
126  */
127 #define PERF_SAMPLE_BRANCH_PERM_PLM \
128         (PERF_SAMPLE_BRANCH_KERNEL |\
129          PERF_SAMPLE_BRANCH_HV)
130 
131 enum event_type_t {
132         EVENT_FLEXIBLE = 0x1,
133         EVENT_PINNED = 0x2,
134         EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
135 };
136 
137 /*
138  * perf_sched_events : >0 events exist
139  * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
140  */
141 struct static_key_deferred perf_sched_events __read_mostly;
142 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
143 static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events);
144 
145 static atomic_t nr_mmap_events __read_mostly;
146 static atomic_t nr_comm_events __read_mostly;
147 static atomic_t nr_task_events __read_mostly;
148 
149 static LIST_HEAD(pmus);
150 static DEFINE_MUTEX(pmus_lock);
151 static struct srcu_struct pmus_srcu;
152 
153 /*
154  * perf event paranoia level:
155  *  -1 - not paranoid at all
156  *   0 - disallow raw tracepoint access for unpriv
157  *   1 - disallow cpu events for unpriv
158  *   2 - disallow kernel profiling for unpriv
159  */
160 int sysctl_perf_event_paranoid __read_mostly = 1;
161 
162 /* Minimum for 512 kiB + 1 user control page */
163 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
164 
165 /*
166  * max perf event sample rate
167  */
168 #define DEFAULT_MAX_SAMPLE_RATE         100000
169 #define DEFAULT_SAMPLE_PERIOD_NS        (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
170 #define DEFAULT_CPU_TIME_MAX_PERCENT    25
171 
172 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
173 
174 static int max_samples_per_tick __read_mostly   = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
175 static int perf_sample_period_ns __read_mostly  = DEFAULT_SAMPLE_PERIOD_NS;
176 
177 static atomic_t perf_sample_allowed_ns __read_mostly =
178         ATOMIC_INIT( DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100);
179 
180 void update_perf_cpu_limits(void)
181 {
182         u64 tmp = perf_sample_period_ns;
183 
184         tmp *= sysctl_perf_cpu_time_max_percent;
185         do_div(tmp, 100);
186         atomic_set(&perf_sample_allowed_ns, tmp);
187 }
188 
189 static int perf_rotate_context(struct perf_cpu_context *cpuctx);
190 
191 int perf_proc_update_handler(struct ctl_table *table, int write,
192                 void __user *buffer, size_t *lenp,
193                 loff_t *ppos)
194 {
195         int ret = proc_dointvec(table, write, buffer, lenp, ppos);
196 
197         if (ret || !write)
198                 return ret;
199 
200         max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
201         perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
202         update_perf_cpu_limits();
203 
204         return 0;
205 }
206 
207 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
208 
209 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
210                                 void __user *buffer, size_t *lenp,
211                                 loff_t *ppos)
212 {
213         int ret = proc_dointvec(table, write, buffer, lenp, ppos);
214 
215         if (ret || !write)
216                 return ret;
217 
218         update_perf_cpu_limits();
219 
220         return 0;
221 }
222 
223 /*
224  * perf samples are done in some very critical code paths (NMIs).
225  * If they take too much CPU time, the system can lock up and not
226  * get any real work done.  This will drop the sample rate when
227  * we detect that events are taking too long.
228  */
229 #define NR_ACCUMULATED_SAMPLES 128
230 DEFINE_PER_CPU(u64, running_sample_length);
231 
232 void perf_sample_event_took(u64 sample_len_ns)
233 {
234         u64 avg_local_sample_len;
235         u64 local_samples_len;
236 
237         if (atomic_read(&perf_sample_allowed_ns) == 0)
238                 return;
239 
240         /* decay the counter by 1 average sample */
241         local_samples_len = __get_cpu_var(running_sample_length);
242         local_samples_len -= local_samples_len/NR_ACCUMULATED_SAMPLES;
243         local_samples_len += sample_len_ns;
244         __get_cpu_var(running_sample_length) = local_samples_len;
245 
246         /*
247          * note: this will be biased artifically low until we have
248          * seen NR_ACCUMULATED_SAMPLES.  Doing it this way keeps us
249          * from having to maintain a count.
250          */
251         avg_local_sample_len = local_samples_len/NR_ACCUMULATED_SAMPLES;
252 
253         if (avg_local_sample_len <= atomic_read(&perf_sample_allowed_ns))
254                 return;
255 
256         if (max_samples_per_tick <= 1)
257                 return;
258 
259         max_samples_per_tick = DIV_ROUND_UP(max_samples_per_tick, 2);
260         sysctl_perf_event_sample_rate = max_samples_per_tick * HZ;
261         perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
262 
263         printk_ratelimited(KERN_WARNING
264                         "perf samples too long (%lld > %d), lowering "
265                         "kernel.perf_event_max_sample_rate to %d\n",
266                         avg_local_sample_len,
267                         atomic_read(&perf_sample_allowed_ns),
268                         sysctl_perf_event_sample_rate);
269 
270         update_perf_cpu_limits();
271 }
272 
273 static atomic64_t perf_event_id;
274 
275 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
276                               enum event_type_t event_type);
277 
278 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
279                              enum event_type_t event_type,
280                              struct task_struct *task);
281 
282 static void update_context_time(struct perf_event_context *ctx);
283 static u64 perf_event_time(struct perf_event *event);
284 
285 void __weak perf_event_print_debug(void)        { }
286 
287 extern __weak const char *perf_pmu_name(void)
288 {
289         return "pmu";
290 }
291 
292 static inline u64 perf_clock(void)
293 {
294         return local_clock();
295 }
296 
297 static inline struct perf_cpu_context *
298 __get_cpu_context(struct perf_event_context *ctx)
299 {
300         return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
301 }
302 
303 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
304                           struct perf_event_context *ctx)
305 {
306         raw_spin_lock(&cpuctx->ctx.lock);
307         if (ctx)
308                 raw_spin_lock(&ctx->lock);
309 }
310 
311 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
312                             struct perf_event_context *ctx)
313 {
314         if (ctx)
315                 raw_spin_unlock(&ctx->lock);
316         raw_spin_unlock(&cpuctx->ctx.lock);
317 }
318 
319 #ifdef CONFIG_CGROUP_PERF
320 
321 /*
322  * perf_cgroup_info keeps track of time_enabled for a cgroup.
323  * This is a per-cpu dynamically allocated data structure.
324  */
325 struct perf_cgroup_info {
326         u64                             time;
327         u64                             timestamp;
328 };
329 
330 struct perf_cgroup {
331         struct cgroup_subsys_state      css;
332         struct perf_cgroup_info __percpu *info;
333 };
334 
335 /*
336  * Must ensure cgroup is pinned (css_get) before calling
337  * this function. In other words, we cannot call this function
338  * if there is no cgroup event for the current CPU context.
339  */
340 static inline struct perf_cgroup *
341 perf_cgroup_from_task(struct task_struct *task)
342 {
343         return container_of(task_subsys_state(task, perf_subsys_id),
344                         struct perf_cgroup, css);
345 }
346 
347 static inline bool
348 perf_cgroup_match(struct perf_event *event)
349 {
350         struct perf_event_context *ctx = event->ctx;
351         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
352 
353         /* @event doesn't care about cgroup */
354         if (!event->cgrp)
355                 return true;
356 
357         /* wants specific cgroup scope but @cpuctx isn't associated with any */
358         if (!cpuctx->cgrp)
359                 return false;
360 
361         /*
362          * Cgroup scoping is recursive.  An event enabled for a cgroup is
363          * also enabled for all its descendant cgroups.  If @cpuctx's
364          * cgroup is a descendant of @event's (the test covers identity
365          * case), it's a match.
366          */
367         return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
368                                     event->cgrp->css.cgroup);
369 }
370 
371 static inline bool perf_tryget_cgroup(struct perf_event *event)
372 {
373         return css_tryget(&event->cgrp->css);
374 }
375 
376 static inline void perf_put_cgroup(struct perf_event *event)
377 {
378         css_put(&event->cgrp->css);
379 }
380 
381 static inline void perf_detach_cgroup(struct perf_event *event)
382 {
383         perf_put_cgroup(event);
384         event->cgrp = NULL;
385 }
386 
387 static inline int is_cgroup_event(struct perf_event *event)
388 {
389         return event->cgrp != NULL;
390 }
391 
392 static inline u64 perf_cgroup_event_time(struct perf_event *event)
393 {
394         struct perf_cgroup_info *t;
395 
396         t = per_cpu_ptr(event->cgrp->info, event->cpu);
397         return t->time;
398 }
399 
400 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
401 {
402         struct perf_cgroup_info *info;
403         u64 now;
404 
405         now = perf_clock();
406 
407         info = this_cpu_ptr(cgrp->info);
408 
409         info->time += now - info->timestamp;
410         info->timestamp = now;
411 }
412 
413 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
414 {
415         struct perf_cgroup *cgrp_out = cpuctx->cgrp;
416         if (cgrp_out)
417                 __update_cgrp_time(cgrp_out);
418 }
419 
420 static inline void update_cgrp_time_from_event(struct perf_event *event)
421 {
422         struct perf_cgroup *cgrp;
423 
424         /*
425          * ensure we access cgroup data only when needed and
426          * when we know the cgroup is pinned (css_get)
427          */
428         if (!is_cgroup_event(event))
429                 return;
430 
431         cgrp = perf_cgroup_from_task(current);
432         /*
433          * Do not update time when cgroup is not active
434          */
435         if (cgrp == event->cgrp)
436                 __update_cgrp_time(event->cgrp);
437 }
438 
439 static inline void
440 perf_cgroup_set_timestamp(struct task_struct *task,
441                           struct perf_event_context *ctx)
442 {
443         struct perf_cgroup *cgrp;
444         struct perf_cgroup_info *info;
445 
446         /*
447          * ctx->lock held by caller
448          * ensure we do not access cgroup data
449          * unless we have the cgroup pinned (css_get)
450          */
451         if (!task || !ctx->nr_cgroups)
452                 return;
453 
454         cgrp = perf_cgroup_from_task(task);
455         info = this_cpu_ptr(cgrp->info);
456         info->timestamp = ctx->timestamp;
457 }
458 
459 #define PERF_CGROUP_SWOUT       0x1 /* cgroup switch out every event */
460 #define PERF_CGROUP_SWIN        0x2 /* cgroup switch in events based on task */
461 
462 /*
463  * reschedule events based on the cgroup constraint of task.
464  *
465  * mode SWOUT : schedule out everything
466  * mode SWIN : schedule in based on cgroup for next
467  */
468 void perf_cgroup_switch(struct task_struct *task, int mode)
469 {
470         struct perf_cpu_context *cpuctx;
471         struct pmu *pmu;
472         unsigned long flags;
473 
474         /*
475          * disable interrupts to avoid geting nr_cgroup
476          * changes via __perf_event_disable(). Also
477          * avoids preemption.
478          */
479         local_irq_save(flags);
480 
481         /*
482          * we reschedule only in the presence of cgroup
483          * constrained events.
484          */
485         rcu_read_lock();
486 
487         list_for_each_entry_rcu(pmu, &pmus, entry) {
488                 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
489                 if (cpuctx->unique_pmu != pmu)
490                         continue; /* ensure we process each cpuctx once */
491 
492                 /*
493                  * perf_cgroup_events says at least one
494                  * context on this CPU has cgroup events.
495                  *
496                  * ctx->nr_cgroups reports the number of cgroup
497                  * events for a context.
498                  */
499                 if (cpuctx->ctx.nr_cgroups > 0) {
500                         perf_ctx_lock(cpuctx, cpuctx->task_ctx);
501                         perf_pmu_disable(cpuctx->ctx.pmu);
502 
503                         if (mode & PERF_CGROUP_SWOUT) {
504                                 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
505                                 /*
506                                  * must not be done before ctxswout due
507                                  * to event_filter_match() in event_sched_out()
508                                  */
509                                 cpuctx->cgrp = NULL;
510                         }
511 
512                         if (mode & PERF_CGROUP_SWIN) {
513                                 WARN_ON_ONCE(cpuctx->cgrp);
514                                 /*
515                                  * set cgrp before ctxsw in to allow
516                                  * event_filter_match() to not have to pass
517                                  * task around
518                                  */
519                                 cpuctx->cgrp = perf_cgroup_from_task(task);
520                                 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
521                         }
522                         perf_pmu_enable(cpuctx->ctx.pmu);
523                         perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
524                 }
525         }
526 
527         rcu_read_unlock();
528 
529         local_irq_restore(flags);
530 }
531 
532 static inline void perf_cgroup_sched_out(struct task_struct *task,
533                                          struct task_struct *next)
534 {
535         struct perf_cgroup *cgrp1;
536         struct perf_cgroup *cgrp2 = NULL;
537 
538         /*
539          * we come here when we know perf_cgroup_events > 0
540          */
541         cgrp1 = perf_cgroup_from_task(task);
542 
543         /*
544          * next is NULL when called from perf_event_enable_on_exec()
545          * that will systematically cause a cgroup_switch()
546          */
547         if (next)
548                 cgrp2 = perf_cgroup_from_task(next);
549 
550         /*
551          * only schedule out current cgroup events if we know
552          * that we are switching to a different cgroup. Otherwise,
553          * do no touch the cgroup events.
554          */
555         if (cgrp1 != cgrp2)
556                 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
557 }
558 
559 static inline void perf_cgroup_sched_in(struct task_struct *prev,
560                                         struct task_struct *task)
561 {
562         struct perf_cgroup *cgrp1;
563         struct perf_cgroup *cgrp2 = NULL;
564 
565         /*
566          * we come here when we know perf_cgroup_events > 0
567          */
568         cgrp1 = perf_cgroup_from_task(task);
569 
570         /* prev can never be NULL */
571         cgrp2 = perf_cgroup_from_task(prev);
572 
573         /*
574          * only need to schedule in cgroup events if we are changing
575          * cgroup during ctxsw. Cgroup events were not scheduled
576          * out of ctxsw out if that was not the case.
577          */
578         if (cgrp1 != cgrp2)
579                 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
580 }
581 
582 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
583                                       struct perf_event_attr *attr,
584                                       struct perf_event *group_leader)
585 {
586         struct perf_cgroup *cgrp;
587         struct cgroup_subsys_state *css;
588         struct fd f = fdget(fd);
589         int ret = 0;
590 
591         if (!f.file)
592                 return -EBADF;
593 
594         css = cgroup_css_from_dir(f.file, perf_subsys_id);
595         if (IS_ERR(css)) {
596                 ret = PTR_ERR(css);
597                 goto out;
598         }
599 
600         cgrp = container_of(css, struct perf_cgroup, css);
601         event->cgrp = cgrp;
602 
603         /* must be done before we fput() the file */
604         if (!perf_tryget_cgroup(event)) {
605                 event->cgrp = NULL;
606                 ret = -ENOENT;
607                 goto out;
608         }
609 
610         /*
611          * all events in a group must monitor
612          * the same cgroup because a task belongs
613          * to only one perf cgroup at a time
614          */
615         if (group_leader && group_leader->cgrp != cgrp) {
616                 perf_detach_cgroup(event);
617                 ret = -EINVAL;
618         }
619 out:
620         fdput(f);
621         return ret;
622 }
623 
624 static inline void
625 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
626 {
627         struct perf_cgroup_info *t;
628         t = per_cpu_ptr(event->cgrp->info, event->cpu);
629         event->shadow_ctx_time = now - t->timestamp;
630 }
631 
632 static inline void
633 perf_cgroup_defer_enabled(struct perf_event *event)
634 {
635         /*
636          * when the current task's perf cgroup does not match
637          * the event's, we need to remember to call the
638          * perf_mark_enable() function the first time a task with
639          * a matching perf cgroup is scheduled in.
640          */
641         if (is_cgroup_event(event) && !perf_cgroup_match(event))
642                 event->cgrp_defer_enabled = 1;
643 }
644 
645 static inline void
646 perf_cgroup_mark_enabled(struct perf_event *event,
647                          struct perf_event_context *ctx)
648 {
649         struct perf_event *sub;
650         u64 tstamp = perf_event_time(event);
651 
652         if (!event->cgrp_defer_enabled)
653                 return;
654 
655         event->cgrp_defer_enabled = 0;
656 
657         event->tstamp_enabled = tstamp - event->total_time_enabled;
658         list_for_each_entry(sub, &event->sibling_list, group_entry) {
659                 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
660                         sub->tstamp_enabled = tstamp - sub->total_time_enabled;
661                         sub->cgrp_defer_enabled = 0;
662                 }
663         }
664 }
665 #else /* !CONFIG_CGROUP_PERF */
666 
667 static inline bool
668 perf_cgroup_match(struct perf_event *event)
669 {
670         return true;
671 }
672 
673 static inline void perf_detach_cgroup(struct perf_event *event)
674 {}
675 
676 static inline int is_cgroup_event(struct perf_event *event)
677 {
678         return 0;
679 }
680 
681 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
682 {
683         return 0;
684 }
685 
686 static inline void update_cgrp_time_from_event(struct perf_event *event)
687 {
688 }
689 
690 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
691 {
692 }
693 
694 static inline void perf_cgroup_sched_out(struct task_struct *task,
695                                          struct task_struct *next)
696 {
697 }
698 
699 static inline void perf_cgroup_sched_in(struct task_struct *prev,
700                                         struct task_struct *task)
701 {
702 }
703 
704 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
705                                       struct perf_event_attr *attr,
706                                       struct perf_event *group_leader)
707 {
708         return -EINVAL;
709 }
710 
711 static inline void
712 perf_cgroup_set_timestamp(struct task_struct *task,
713                           struct perf_event_context *ctx)
714 {
715 }
716 
717 void
718 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
719 {
720 }
721 
722 static inline void
723 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
724 {
725 }
726 
727 static inline u64 perf_cgroup_event_time(struct perf_event *event)
728 {
729         return 0;
730 }
731 
732 static inline void
733 perf_cgroup_defer_enabled(struct perf_event *event)
734 {
735 }
736 
737 static inline void
738 perf_cgroup_mark_enabled(struct perf_event *event,
739                          struct perf_event_context *ctx)
740 {
741 }
742 #endif
743 
744 /*
745  * set default to be dependent on timer tick just
746  * like original code
747  */
748 #define PERF_CPU_HRTIMER (1000 / HZ)
749 /*
750  * function must be called with interrupts disbled
751  */
752 static enum hrtimer_restart perf_cpu_hrtimer_handler(struct hrtimer *hr)
753 {
754         struct perf_cpu_context *cpuctx;
755         enum hrtimer_restart ret = HRTIMER_NORESTART;
756         int rotations = 0;
757 
758         WARN_ON(!irqs_disabled());
759 
760         cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
761 
762         rotations = perf_rotate_context(cpuctx);
763 
764         /*
765          * arm timer if needed
766          */
767         if (rotations) {
768                 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
769                 ret = HRTIMER_RESTART;
770         }
771 
772         return ret;
773 }
774 
775 /* CPU is going down */
776 void perf_cpu_hrtimer_cancel(int cpu)
777 {
778         struct perf_cpu_context *cpuctx;
779         struct pmu *pmu;
780         unsigned long flags;
781 
782         if (WARN_ON(cpu != smp_processor_id()))
783                 return;
784 
785         local_irq_save(flags);
786 
787         rcu_read_lock();
788 
789         list_for_each_entry_rcu(pmu, &pmus, entry) {
790                 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
791 
792                 if (pmu->task_ctx_nr == perf_sw_context)
793                         continue;
794 
795                 hrtimer_cancel(&cpuctx->hrtimer);
796         }
797 
798         rcu_read_unlock();
799 
800         local_irq_restore(flags);
801 }
802 
803 static void __perf_cpu_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
804 {
805         struct hrtimer *hr = &cpuctx->hrtimer;
806         struct pmu *pmu = cpuctx->ctx.pmu;
807         int timer;
808 
809         /* no multiplexing needed for SW PMU */
810         if (pmu->task_ctx_nr == perf_sw_context)
811                 return;
812 
813         /*
814          * check default is sane, if not set then force to
815          * default interval (1/tick)
816          */
817         timer = pmu->hrtimer_interval_ms;
818         if (timer < 1)
819                 timer = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
820 
821         cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
822 
823         hrtimer_init(hr, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
824         hr->function = perf_cpu_hrtimer_handler;
825 }
826 
827 static void perf_cpu_hrtimer_restart(struct perf_cpu_context *cpuctx)
828 {
829         struct hrtimer *hr = &cpuctx->hrtimer;
830         struct pmu *pmu = cpuctx->ctx.pmu;
831 
832         /* not for SW PMU */
833         if (pmu->task_ctx_nr == perf_sw_context)
834                 return;
835 
836         if (hrtimer_active(hr))
837                 return;
838 
839         if (!hrtimer_callback_running(hr))
840                 __hrtimer_start_range_ns(hr, cpuctx->hrtimer_interval,
841                                          0, HRTIMER_MODE_REL_PINNED, 0);
842 }
843 
844 void perf_pmu_disable(struct pmu *pmu)
845 {
846         int *count = this_cpu_ptr(pmu->pmu_disable_count);
847         if (!(*count)++)
848                 pmu->pmu_disable(pmu);
849 }
850 
851 void perf_pmu_enable(struct pmu *pmu)
852 {
853         int *count = this_cpu_ptr(pmu->pmu_disable_count);
854         if (!--(*count))
855                 pmu->pmu_enable(pmu);
856 }
857 
858 static DEFINE_PER_CPU(struct list_head, rotation_list);
859 
860 /*
861  * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
862  * because they're strictly cpu affine and rotate_start is called with IRQs
863  * disabled, while rotate_context is called from IRQ context.
864  */
865 static void perf_pmu_rotate_start(struct pmu *pmu)
866 {
867         struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
868         struct list_head *head = &__get_cpu_var(rotation_list);
869 
870         WARN_ON(!irqs_disabled());
871 
872         if (list_empty(&cpuctx->rotation_list)) {
873                 int was_empty = list_empty(head);
874                 list_add(&cpuctx->rotation_list, head);
875                 if (was_empty)
876                         tick_nohz_full_kick();
877         }
878 }
879 
880 static void get_ctx(struct perf_event_context *ctx)
881 {
882         WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
883 }
884 
885 static void put_ctx(struct perf_event_context *ctx)
886 {
887         if (atomic_dec_and_test(&ctx->refcount)) {
888                 if (ctx->parent_ctx)
889                         put_ctx(ctx->parent_ctx);
890                 if (ctx->task)
891                         put_task_struct(ctx->task);
892                 kfree_rcu(ctx, rcu_head);
893         }
894 }
895 
896 static void unclone_ctx(struct perf_event_context *ctx)
897 {
898         if (ctx->parent_ctx) {
899                 put_ctx(ctx->parent_ctx);
900                 ctx->parent_ctx = NULL;
901         }
902 }
903 
904 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
905 {
906         /*
907          * only top level events have the pid namespace they were created in
908          */
909         if (event->parent)
910                 event = event->parent;
911 
912         return task_tgid_nr_ns(p, event->ns);
913 }
914 
915 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
916 {
917         /*
918          * only top level events have the pid namespace they were created in
919          */
920         if (event->parent)
921                 event = event->parent;
922 
923         return task_pid_nr_ns(p, event->ns);
924 }
925 
926 /*
927  * If we inherit events we want to return the parent event id
928  * to userspace.
929  */
930 static u64 primary_event_id(struct perf_event *event)
931 {
932         u64 id = event->id;
933 
934         if (event->parent)
935                 id = event->parent->id;
936 
937         return id;
938 }
939 
940 /*
941  * Get the perf_event_context for a task and lock it.
942  * This has to cope with with the fact that until it is locked,
943  * the context could get moved to another task.
944  */
945 static struct perf_event_context *
946 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
947 {
948         struct perf_event_context *ctx;
949 
950 retry:
951         /*
952          * One of the few rules of preemptible RCU is that one cannot do
953          * rcu_read_unlock() while holding a scheduler (or nested) lock when
954          * part of the read side critical section was preemptible -- see
955          * rcu_read_unlock_special().
956          *
957          * Since ctx->lock nests under rq->lock we must ensure the entire read
958          * side critical section is non-preemptible.
959          */
960         preempt_disable();
961         rcu_read_lock();
962         ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
963         if (ctx) {
964                 /*
965                  * If this context is a clone of another, it might
966                  * get swapped for another underneath us by
967                  * perf_event_task_sched_out, though the
968                  * rcu_read_lock() protects us from any context
969                  * getting freed.  Lock the context and check if it
970                  * got swapped before we could get the lock, and retry
971                  * if so.  If we locked the right context, then it
972                  * can't get swapped on us any more.
973                  */
974                 raw_spin_lock_irqsave(&ctx->lock, *flags);
975                 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
976                         raw_spin_unlock_irqrestore(&ctx->lock, *flags);
977                         rcu_read_unlock();
978                         preempt_enable();
979                         goto retry;
980                 }
981 
982                 if (!atomic_inc_not_zero(&ctx->refcount)) {
983                         raw_spin_unlock_irqrestore(&ctx->lock, *flags);
984                         ctx = NULL;
985                 }
986         }
987         rcu_read_unlock();
988         preempt_enable();
989         return ctx;
990 }
991 
992 /*
993  * Get the context for a task and increment its pin_count so it
994  * can't get swapped to another task.  This also increments its
995  * reference count so that the context can't get freed.
996  */
997 static struct perf_event_context *
998 perf_pin_task_context(struct task_struct *task, int ctxn)
999 {
1000         struct perf_event_context *ctx;
1001         unsigned long flags;
1002 
1003         ctx = perf_lock_task_context(task, ctxn, &flags);
1004         if (ctx) {
1005                 ++ctx->pin_count;
1006                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1007         }
1008         return ctx;
1009 }
1010 
1011 static void perf_unpin_context(struct perf_event_context *ctx)
1012 {
1013         unsigned long flags;
1014 
1015         raw_spin_lock_irqsave(&ctx->lock, flags);
1016         --ctx->pin_count;
1017         raw_spin_unlock_irqrestore(&ctx->lock, flags);
1018 }
1019 
1020 /*
1021  * Update the record of the current time in a context.
1022  */
1023 static void update_context_time(struct perf_event_context *ctx)
1024 {
1025         u64 now = perf_clock();
1026 
1027         ctx->time += now - ctx->timestamp;
1028         ctx->timestamp = now;
1029 }
1030 
1031 static u64 perf_event_time(struct perf_event *event)
1032 {
1033         struct perf_event_context *ctx = event->ctx;
1034 
1035         if (is_cgroup_event(event))
1036                 return perf_cgroup_event_time(event);
1037 
1038         return ctx ? ctx->time : 0;
1039 }
1040 
1041 /*
1042  * Update the total_time_enabled and total_time_running fields for a event.
1043  * The caller of this function needs to hold the ctx->lock.
1044  */
1045 static void update_event_times(struct perf_event *event)
1046 {
1047         struct perf_event_context *ctx = event->ctx;
1048         u64 run_end;
1049 
1050         if (event->state < PERF_EVENT_STATE_INACTIVE ||
1051             event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
1052                 return;
1053         /*
1054          * in cgroup mode, time_enabled represents
1055          * the time the event was enabled AND active
1056          * tasks were in the monitored cgroup. This is
1057          * independent of the activity of the context as
1058          * there may be a mix of cgroup and non-cgroup events.
1059          *
1060          * That is why we treat cgroup events differently
1061          * here.
1062          */
1063         if (is_cgroup_event(event))
1064                 run_end = perf_cgroup_event_time(event);
1065         else if (ctx->is_active)
1066                 run_end = ctx->time;
1067         else
1068                 run_end = event->tstamp_stopped;
1069 
1070         event->total_time_enabled = run_end - event->tstamp_enabled;
1071 
1072         if (event->state == PERF_EVENT_STATE_INACTIVE)
1073                 run_end = event->tstamp_stopped;
1074         else
1075                 run_end = perf_event_time(event);
1076 
1077         event->total_time_running = run_end - event->tstamp_running;
1078 
1079 }
1080 
1081 /*
1082  * Update total_time_enabled and total_time_running for all events in a group.
1083  */
1084 static void update_group_times(struct perf_event *leader)
1085 {
1086         struct perf_event *event;
1087 
1088         update_event_times(leader);
1089         list_for_each_entry(event, &leader->sibling_list, group_entry)
1090                 update_event_times(event);
1091 }
1092 
1093 static struct list_head *
1094 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
1095 {
1096         if (event->attr.pinned)
1097                 return &ctx->pinned_groups;
1098         else
1099                 return &ctx->flexible_groups;
1100 }
1101 
1102 /*
1103  * Add a event from the lists for its context.
1104  * Must be called with ctx->mutex and ctx->lock held.
1105  */
1106 static void
1107 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1108 {
1109         WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1110         event->attach_state |= PERF_ATTACH_CONTEXT;
1111 
1112         /*
1113          * If we're a stand alone event or group leader, we go to the context
1114          * list, group events are kept attached to the group so that
1115          * perf_group_detach can, at all times, locate all siblings.
1116          */
1117         if (event->group_leader == event) {
1118                 struct list_head *list;
1119 
1120                 if (is_software_event(event))
1121                         event->group_flags |= PERF_GROUP_SOFTWARE;
1122 
1123                 list = ctx_group_list(event, ctx);
1124                 list_add_tail(&event->group_entry, list);
1125         }
1126 
1127         if (is_cgroup_event(event))
1128                 ctx->nr_cgroups++;
1129 
1130         if (has_branch_stack(event))
1131                 ctx->nr_branch_stack++;
1132 
1133         list_add_rcu(&event->event_entry, &ctx->event_list);
1134         if (!ctx->nr_events)
1135                 perf_pmu_rotate_start(ctx->pmu);
1136         ctx->nr_events++;
1137         if (event->attr.inherit_stat)
1138                 ctx->nr_stat++;
1139 }
1140 
1141 /*
1142  * Initialize event state based on the perf_event_attr::disabled.
1143  */
1144 static inline void perf_event__state_init(struct perf_event *event)
1145 {
1146         event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1147                                               PERF_EVENT_STATE_INACTIVE;
1148 }
1149 
1150 /*
1151  * Called at perf_event creation and when events are attached/detached from a
1152  * group.
1153  */
1154 static void perf_event__read_size(struct perf_event *event)
1155 {
1156         int entry = sizeof(u64); /* value */
1157         int size = 0;
1158         int nr = 1;
1159 
1160         if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1161                 size += sizeof(u64);
1162 
1163         if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1164                 size += sizeof(u64);
1165 
1166         if (event->attr.read_format & PERF_FORMAT_ID)
1167                 entry += sizeof(u64);
1168 
1169         if (event->attr.read_format & PERF_FORMAT_GROUP) {
1170                 nr += event->group_leader->nr_siblings;
1171                 size += sizeof(u64);
1172         }
1173 
1174         size += entry * nr;
1175         event->read_size = size;
1176 }
1177 
1178 static void perf_event__header_size(struct perf_event *event)
1179 {
1180         struct perf_sample_data *data;
1181         u64 sample_type = event->attr.sample_type;
1182         u16 size = 0;
1183 
1184         perf_event__read_size(event);
1185 
1186         if (sample_type & PERF_SAMPLE_IP)
1187                 size += sizeof(data->ip);
1188 
1189         if (sample_type & PERF_SAMPLE_ADDR)
1190                 size += sizeof(data->addr);
1191 
1192         if (sample_type & PERF_SAMPLE_PERIOD)
1193                 size += sizeof(data->period);
1194 
1195         if (sample_type & PERF_SAMPLE_WEIGHT)
1196                 size += sizeof(data->weight);
1197 
1198         if (sample_type & PERF_SAMPLE_READ)
1199                 size += event->read_size;
1200 
1201         if (sample_type & PERF_SAMPLE_DATA_SRC)
1202                 size += sizeof(data->data_src.val);
1203 
1204         event->header_size = size;
1205 }
1206 
1207 static void perf_event__id_header_size(struct perf_event *event)
1208 {
1209         struct perf_sample_data *data;
1210         u64 sample_type = event->attr.sample_type;
1211         u16 size = 0;
1212 
1213         if (sample_type & PERF_SAMPLE_TID)
1214                 size += sizeof(data->tid_entry);
1215 
1216         if (sample_type & PERF_SAMPLE_TIME)
1217                 size += sizeof(data->time);
1218 
1219         if (sample_type & PERF_SAMPLE_ID)
1220                 size += sizeof(data->id);
1221 
1222         if (sample_type & PERF_SAMPLE_STREAM_ID)
1223                 size += sizeof(data->stream_id);
1224 
1225         if (sample_type & PERF_SAMPLE_CPU)
1226                 size += sizeof(data->cpu_entry);
1227 
1228         event->id_header_size = size;
1229 }
1230 
1231 static void perf_group_attach(struct perf_event *event)
1232 {
1233         struct perf_event *group_leader = event->group_leader, *pos;
1234 
1235         /*
1236          * We can have double attach due to group movement in perf_event_open.
1237          */
1238         if (event->attach_state & PERF_ATTACH_GROUP)
1239                 return;
1240 
1241         event->attach_state |= PERF_ATTACH_GROUP;
1242 
1243         if (group_leader == event)
1244                 return;
1245 
1246         if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
1247                         !is_software_event(event))
1248                 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
1249 
1250         list_add_tail(&event->group_entry, &group_leader->sibling_list);
1251         group_leader->nr_siblings++;
1252 
1253         perf_event__header_size(group_leader);
1254 
1255         list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
1256                 perf_event__header_size(pos);
1257 }
1258 
1259 /*
1260  * Remove a event from the lists for its context.
1261  * Must be called with ctx->mutex and ctx->lock held.
1262  */
1263 static void
1264 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1265 {
1266         struct perf_cpu_context *cpuctx;
1267         /*
1268          * We can have double detach due to exit/hot-unplug + close.
1269          */
1270         if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1271                 return;
1272 
1273         event->attach_state &= ~PERF_ATTACH_CONTEXT;
1274 
1275         if (is_cgroup_event(event)) {
1276                 ctx->nr_cgroups--;
1277                 cpuctx = __get_cpu_context(ctx);
1278                 /*
1279                  * if there are no more cgroup events
1280                  * then cler cgrp to avoid stale pointer
1281                  * in update_cgrp_time_from_cpuctx()
1282                  */
1283                 if (!ctx->nr_cgroups)
1284                         cpuctx->cgrp = NULL;
1285         }
1286 
1287         if (has_branch_stack(event))
1288                 ctx->nr_branch_stack--;
1289 
1290         ctx->nr_events--;
1291         if (event->attr.inherit_stat)
1292                 ctx->nr_stat--;
1293 
1294         list_del_rcu(&event->event_entry);
1295 
1296         if (event->group_leader == event)
1297                 list_del_init(&event->group_entry);
1298 
1299         update_group_times(event);
1300 
1301         /*
1302          * If event was in error state, then keep it
1303          * that way, otherwise bogus counts will be
1304          * returned on read(). The only way to get out
1305          * of error state is by explicit re-enabling
1306          * of the event
1307          */
1308         if (event->state > PERF_EVENT_STATE_OFF)
1309                 event->state = PERF_EVENT_STATE_OFF;
1310 }
1311 
1312 static void perf_group_detach(struct perf_event *event)
1313 {
1314         struct perf_event *sibling, *tmp;
1315         struct list_head *list = NULL;
1316 
1317         /*
1318          * We can have double detach due to exit/hot-unplug + close.
1319          */
1320         if (!(event->attach_state & PERF_ATTACH_GROUP))
1321                 return;
1322 
1323         event->attach_state &= ~PERF_ATTACH_GROUP;
1324 
1325         /*
1326          * If this is a sibling, remove it from its group.
1327          */
1328         if (event->group_leader != event) {
1329                 list_del_init(&event->group_entry);
1330                 event->group_leader->nr_siblings--;
1331                 goto out;
1332         }
1333 
1334         if (!list_empty(&event->group_entry))
1335                 list = &event->group_entry;
1336 
1337         /*
1338          * If this was a group event with sibling events then
1339          * upgrade the siblings to singleton events by adding them
1340          * to whatever list we are on.
1341          */
1342         list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1343                 if (list)
1344                         list_move_tail(&sibling->group_entry, list);
1345                 sibling->group_leader = sibling;
1346 
1347                 /* Inherit group flags from the previous leader */
1348                 sibling->group_flags = event->group_flags;
1349         }
1350 
1351 out:
1352         perf_event__header_size(event->group_leader);
1353 
1354         list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1355                 perf_event__header_size(tmp);
1356 }
1357 
1358 static inline int
1359 event_filter_match(struct perf_event *event)
1360 {
1361         return (event->cpu == -1 || event->cpu == smp_processor_id())
1362             && perf_cgroup_match(event);
1363 }
1364 
1365 static void
1366 event_sched_out(struct perf_event *event,
1367                   struct perf_cpu_context *cpuctx,
1368                   struct perf_event_context *ctx)
1369 {
1370         u64 tstamp = perf_event_time(event);
1371         u64 delta;
1372         /*
1373          * An event which could not be activated because of
1374          * filter mismatch still needs to have its timings
1375          * maintained, otherwise bogus information is return
1376          * via read() for time_enabled, time_running:
1377          */
1378         if (event->state == PERF_EVENT_STATE_INACTIVE
1379             && !event_filter_match(event)) {
1380                 delta = tstamp - event->tstamp_stopped;
1381                 event->tstamp_running += delta;
1382                 event->tstamp_stopped = tstamp;
1383         }
1384 
1385         if (event->state != PERF_EVENT_STATE_ACTIVE)
1386                 return;
1387 
1388         event->state = PERF_EVENT_STATE_INACTIVE;
1389         if (event->pending_disable) {
1390                 event->pending_disable = 0;
1391                 event->state = PERF_EVENT_STATE_OFF;
1392         }
1393         event->tstamp_stopped = tstamp;
1394         event->pmu->del(event, 0);
1395         event->oncpu = -1;
1396 
1397         if (!is_software_event(event))
1398                 cpuctx->active_oncpu--;
1399         ctx->nr_active--;
1400         if (event->attr.freq && event->attr.sample_freq)
1401                 ctx->nr_freq--;
1402         if (event->attr.exclusive || !cpuctx->active_oncpu)
1403                 cpuctx->exclusive = 0;
1404 }
1405 
1406 static void
1407 group_sched_out(struct perf_event *group_event,
1408                 struct perf_cpu_context *cpuctx,
1409                 struct perf_event_context *ctx)
1410 {
1411         struct perf_event *event;
1412         int state = group_event->state;
1413 
1414         event_sched_out(group_event, cpuctx, ctx);
1415 
1416         /*
1417          * Schedule out siblings (if any):
1418          */
1419         list_for_each_entry(event, &group_event->sibling_list, group_entry)
1420                 event_sched_out(event, cpuctx, ctx);
1421 
1422         if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1423                 cpuctx->exclusive = 0;
1424 }
1425 
1426 /*
1427  * Cross CPU call to remove a performance event
1428  *
1429  * We disable the event on the hardware level first. After that we
1430  * remove it from the context list.
1431  */
1432 static int __perf_remove_from_context(void *info)
1433 {
1434         struct perf_event *event = info;
1435         struct perf_event_context *ctx = event->ctx;
1436         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1437 
1438         raw_spin_lock(&ctx->lock);
1439         event_sched_out(event, cpuctx, ctx);
1440         list_del_event(event, ctx);
1441         if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1442                 ctx->is_active = 0;
1443                 cpuctx->task_ctx = NULL;
1444         }
1445         raw_spin_unlock(&ctx->lock);
1446 
1447         return 0;
1448 }
1449 
1450 
1451 /*
1452  * Remove the event from a task's (or a CPU's) list of events.
1453  *
1454  * CPU events are removed with a smp call. For task events we only
1455  * call when the task is on a CPU.
1456  *
1457  * If event->ctx is a cloned context, callers must make sure that
1458  * every task struct that event->ctx->task could possibly point to
1459  * remains valid.  This is OK when called from perf_release since
1460  * that only calls us on the top-level context, which can't be a clone.
1461  * When called from perf_event_exit_task, it's OK because the
1462  * context has been detached from its task.
1463  */
1464 static void perf_remove_from_context(struct perf_event *event)
1465 {
1466         struct perf_event_context *ctx = event->ctx;
1467         struct task_struct *task = ctx->task;
1468 
1469         lockdep_assert_held(&ctx->mutex);
1470 
1471         if (!task) {
1472                 /*
1473                  * Per cpu events are removed via an smp call and
1474                  * the removal is always successful.
1475                  */
1476                 cpu_function_call(event->cpu, __perf_remove_from_context, event);
1477                 return;
1478         }
1479 
1480 retry:
1481         if (!task_function_call(task, __perf_remove_from_context, event))
1482                 return;
1483 
1484         raw_spin_lock_irq(&ctx->lock);
1485         /*
1486          * If we failed to find a running task, but find the context active now
1487          * that we've acquired the ctx->lock, retry.
1488          */
1489         if (ctx->is_active) {
1490                 raw_spin_unlock_irq(&ctx->lock);
1491                 goto retry;
1492         }
1493 
1494         /*
1495          * Since the task isn't running, its safe to remove the event, us
1496          * holding the ctx->lock ensures the task won't get scheduled in.
1497          */
1498         list_del_event(event, ctx);
1499         raw_spin_unlock_irq(&ctx->lock);
1500 }
1501 
1502 /*
1503  * Cross CPU call to disable a performance event
1504  */
1505 int __perf_event_disable(void *info)
1506 {
1507         struct perf_event *event = info;
1508         struct perf_event_context *ctx = event->ctx;
1509         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1510 
1511         /*
1512          * If this is a per-task event, need to check whether this
1513          * event's task is the current task on this cpu.
1514          *
1515          * Can trigger due to concurrent perf_event_context_sched_out()
1516          * flipping contexts around.
1517          */
1518         if (ctx->task && cpuctx->task_ctx != ctx)
1519                 return -EINVAL;
1520 
1521         raw_spin_lock(&ctx->lock);
1522 
1523         /*
1524          * If the event is on, turn it off.
1525          * If it is in error state, leave it in error state.
1526          */
1527         if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1528                 update_context_time(ctx);
1529                 update_cgrp_time_from_event(event);
1530                 update_group_times(event);
1531                 if (event == event->group_leader)
1532                         group_sched_out(event, cpuctx, ctx);
1533                 else
1534                         event_sched_out(event, cpuctx, ctx);
1535                 event->state = PERF_EVENT_STATE_OFF;
1536         }
1537 
1538         raw_spin_unlock(&ctx->lock);
1539 
1540         return 0;
1541 }
1542 
1543 /*
1544  * Disable a event.
1545  *
1546  * If event->ctx is a cloned context, callers must make sure that
1547  * every task struct that event->ctx->task could possibly point to
1548  * remains valid.  This condition is satisifed when called through
1549  * perf_event_for_each_child or perf_event_for_each because they
1550  * hold the top-level event's child_mutex, so any descendant that
1551  * goes to exit will block in sync_child_event.
1552  * When called from perf_pending_event it's OK because event->ctx
1553  * is the current context on this CPU and preemption is disabled,
1554  * hence we can't get into perf_event_task_sched_out for this context.
1555  */
1556 void perf_event_disable(struct perf_event *event)
1557 {
1558         struct perf_event_context *ctx = event->ctx;
1559         struct task_struct *task = ctx->task;
1560 
1561         if (!task) {
1562                 /*
1563                  * Disable the event on the cpu that it's on
1564                  */
1565                 cpu_function_call(event->cpu, __perf_event_disable, event);
1566                 return;
1567         }
1568 
1569 retry:
1570         if (!task_function_call(task, __perf_event_disable, event))
1571                 return;
1572 
1573         raw_spin_lock_irq(&ctx->lock);
1574         /*
1575          * If the event is still active, we need to retry the cross-call.
1576          */
1577         if (event->state == PERF_EVENT_STATE_ACTIVE) {
1578                 raw_spin_unlock_irq(&ctx->lock);
1579                 /*
1580                  * Reload the task pointer, it might have been changed by
1581                  * a concurrent perf_event_context_sched_out().
1582                  */
1583                 task = ctx->task;
1584                 goto retry;
1585         }
1586 
1587         /*
1588          * Since we have the lock this context can't be scheduled
1589          * in, so we can change the state safely.
1590          */
1591         if (event->state == PERF_EVENT_STATE_INACTIVE) {
1592                 update_group_times(event);
1593                 event->state = PERF_EVENT_STATE_OFF;
1594         }
1595         raw_spin_unlock_irq(&ctx->lock);
1596 }
1597 EXPORT_SYMBOL_GPL(perf_event_disable);
1598 
1599 static void perf_set_shadow_time(struct perf_event *event,
1600                                  struct perf_event_context *ctx,
1601                                  u64 tstamp)
1602 {
1603         /*
1604          * use the correct time source for the time snapshot
1605          *
1606          * We could get by without this by leveraging the
1607          * fact that to get to this function, the caller
1608          * has most likely already called update_context_time()
1609          * and update_cgrp_time_xx() and thus both timestamp
1610          * are identical (or very close). Given that tstamp is,
1611          * already adjusted for cgroup, we could say that:
1612          *    tstamp - ctx->timestamp
1613          * is equivalent to
1614          *    tstamp - cgrp->timestamp.
1615          *
1616          * Then, in perf_output_read(), the calculation would
1617          * work with no changes because:
1618          * - event is guaranteed scheduled in
1619          * - no scheduled out in between
1620          * - thus the timestamp would be the same
1621          *
1622          * But this is a bit hairy.
1623          *
1624          * So instead, we have an explicit cgroup call to remain
1625          * within the time time source all along. We believe it
1626          * is cleaner and simpler to understand.
1627          */
1628         if (is_cgroup_event(event))
1629                 perf_cgroup_set_shadow_time(event, tstamp);
1630         else
1631                 event->shadow_ctx_time = tstamp - ctx->timestamp;
1632 }
1633 
1634 #define MAX_INTERRUPTS (~0ULL)
1635 
1636 static void perf_log_throttle(struct perf_event *event, int enable);
1637 
1638 static int
1639 event_sched_in(struct perf_event *event,
1640                  struct perf_cpu_context *cpuctx,
1641                  struct perf_event_context *ctx)
1642 {
1643         u64 tstamp = perf_event_time(event);
1644 
1645         if (event->state <= PERF_EVENT_STATE_OFF)
1646                 return 0;
1647 
1648         event->state = PERF_EVENT_STATE_ACTIVE;
1649         event->oncpu = smp_processor_id();
1650 
1651         /*
1652          * Unthrottle events, since we scheduled we might have missed several
1653          * ticks already, also for a heavily scheduling task there is little
1654          * guarantee it'll get a tick in a timely manner.
1655          */
1656         if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1657                 perf_log_throttle(event, 1);
1658                 event->hw.interrupts = 0;
1659         }
1660 
1661         /*
1662          * The new state must be visible before we turn it on in the hardware:
1663          */
1664         smp_wmb();
1665 
1666         if (event->pmu->add(event, PERF_EF_START)) {
1667                 event->state = PERF_EVENT_STATE_INACTIVE;
1668                 event->oncpu = -1;
1669                 return -EAGAIN;
1670         }
1671 
1672         event->tstamp_running += tstamp - event->tstamp_stopped;
1673 
1674         perf_set_shadow_time(event, ctx, tstamp);
1675 
1676         if (!is_software_event(event))
1677                 cpuctx->active_oncpu++;
1678         ctx->nr_active++;
1679         if (event->attr.freq && event->attr.sample_freq)
1680                 ctx->nr_freq++;
1681 
1682         if (event->attr.exclusive)
1683                 cpuctx->exclusive = 1;
1684 
1685         return 0;
1686 }
1687 
1688 static int
1689 group_sched_in(struct perf_event *group_event,
1690                struct perf_cpu_context *cpuctx,
1691                struct perf_event_context *ctx)
1692 {
1693         struct perf_event *event, *partial_group = NULL;
1694         struct pmu *pmu = group_event->pmu;
1695         u64 now = ctx->time;
1696         bool simulate = false;
1697 
1698         if (group_event->state == PERF_EVENT_STATE_OFF)
1699                 return 0;
1700 
1701         pmu->start_txn(pmu);
1702 
1703         if (event_sched_in(group_event, cpuctx, ctx)) {
1704                 pmu->cancel_txn(pmu);
1705                 perf_cpu_hrtimer_restart(cpuctx);
1706                 return -EAGAIN;
1707         }
1708 
1709         /*
1710          * Schedule in siblings as one group (if any):
1711          */
1712         list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1713                 if (event_sched_in(event, cpuctx, ctx)) {
1714                         partial_group = event;
1715                         goto group_error;
1716                 }
1717         }
1718 
1719         if (!pmu->commit_txn(pmu))
1720                 return 0;
1721 
1722 group_error:
1723         /*
1724          * Groups can be scheduled in as one unit only, so undo any
1725          * partial group before returning:
1726          * The events up to the failed event are scheduled out normally,
1727          * tstamp_stopped will be updated.
1728          *
1729          * The failed events and the remaining siblings need to have
1730          * their timings updated as if they had gone thru event_sched_in()
1731          * and event_sched_out(). This is required to get consistent timings
1732          * across the group. This also takes care of the case where the group
1733          * could never be scheduled by ensuring tstamp_stopped is set to mark
1734          * the time the event was actually stopped, such that time delta
1735          * calculation in update_event_times() is correct.
1736          */
1737         list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1738                 if (event == partial_group)
1739                         simulate = true;
1740 
1741                 if (simulate) {
1742                         event->tstamp_running += now - event->tstamp_stopped;
1743                         event->tstamp_stopped = now;
1744                 } else {
1745                         event_sched_out(event, cpuctx, ctx);
1746                 }
1747         }
1748         event_sched_out(group_event, cpuctx, ctx);
1749 
1750         pmu->cancel_txn(pmu);
1751 
1752         perf_cpu_hrtimer_restart(cpuctx);
1753 
1754         return -EAGAIN;
1755 }
1756 
1757 /*
1758  * Work out whether we can put this event group on the CPU now.
1759  */
1760 static int group_can_go_on(struct perf_event *event,
1761                            struct perf_cpu_context *cpuctx,
1762                            int can_add_hw)
1763 {
1764         /*
1765          * Groups consisting entirely of software events can always go on.
1766          */
1767         if (event->group_flags & PERF_GROUP_SOFTWARE)
1768                 return 1;
1769         /*
1770          * If an exclusive group is already on, no other hardware
1771          * events can go on.
1772          */
1773         if (cpuctx->exclusive)
1774                 return 0;
1775         /*
1776          * If this group is exclusive and there are already
1777          * events on the CPU, it can't go on.
1778          */
1779         if (event->attr.exclusive && cpuctx->active_oncpu)
1780                 return 0;
1781         /*
1782          * Otherwise, try to add it if all previous groups were able
1783          * to go on.
1784          */
1785         return can_add_hw;
1786 }
1787 
1788 static void add_event_to_ctx(struct perf_event *event,
1789                                struct perf_event_context *ctx)
1790 {
1791         u64 tstamp = perf_event_time(event);
1792 
1793         list_add_event(event, ctx);
1794         perf_group_attach(event);
1795         event->tstamp_enabled = tstamp;
1796         event->tstamp_running = tstamp;
1797         event->tstamp_stopped = tstamp;
1798 }
1799 
1800 static void task_ctx_sched_out(struct perf_event_context *ctx);
1801 static void
1802 ctx_sched_in(struct perf_event_context *ctx,
1803              struct perf_cpu_context *cpuctx,
1804              enum event_type_t event_type,
1805              struct task_struct *task);
1806 
1807 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
1808                                 struct perf_event_context *ctx,
1809                                 struct task_struct *task)
1810 {
1811         cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
1812         if (ctx)
1813                 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
1814         cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
1815         if (ctx)
1816                 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
1817 }
1818 
1819 /*
1820  * Cross CPU call to install and enable a performance event
1821  *
1822  * Must be called with ctx->mutex held
1823  */
1824 static int  __perf_install_in_context(void *info)
1825 {
1826         struct perf_event *event = info;
1827         struct perf_event_context *ctx = event->ctx;
1828         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1829         struct perf_event_context *task_ctx = cpuctx->task_ctx;
1830         struct task_struct *task = current;
1831 
1832         perf_ctx_lock(cpuctx, task_ctx);
1833         perf_pmu_disable(cpuctx->ctx.pmu);
1834 
1835         /*
1836          * If there was an active task_ctx schedule it out.
1837          */
1838         if (task_ctx)
1839                 task_ctx_sched_out(task_ctx);
1840 
1841         /*
1842          * If the context we're installing events in is not the
1843          * active task_ctx, flip them.
1844          */
1845         if (ctx->task && task_ctx != ctx) {
1846                 if (task_ctx)
1847                         raw_spin_unlock(&task_ctx->lock);
1848                 raw_spin_lock(&ctx->lock);
1849                 task_ctx = ctx;
1850         }
1851 
1852         if (task_ctx) {
1853                 cpuctx->task_ctx = task_ctx;
1854                 task = task_ctx->task;
1855         }
1856 
1857         cpu_ctx_sched_out(cpuctx, EVENT_ALL);
1858 
1859         update_context_time(ctx);
1860         /*
1861          * update cgrp time only if current cgrp
1862          * matches event->cgrp. Must be done before
1863          * calling add_event_to_ctx()
1864          */
1865         update_cgrp_time_from_event(event);
1866 
1867         add_event_to_ctx(event, ctx);
1868 
1869         /*
1870          * Schedule everything back in
1871          */
1872         perf_event_sched_in(cpuctx, task_ctx, task);
1873 
1874         perf_pmu_enable(cpuctx->ctx.pmu);
1875         perf_ctx_unlock(cpuctx, task_ctx);
1876 
1877         return 0;
1878 }
1879 
1880 /*
1881  * Attach a performance event to a context
1882  *
1883  * First we add the event to the list with the hardware enable bit
1884  * in event->hw_config cleared.
1885  *
1886  * If the event is attached to a task which is on a CPU we use a smp
1887  * call to enable it in the task context. The task might have been
1888  * scheduled away, but we check this in the smp call again.
1889  */
1890 static void
1891 perf_install_in_context(struct perf_event_context *ctx,
1892                         struct perf_event *event,
1893                         int cpu)
1894 {
1895         struct task_struct *task = ctx->task;
1896 
1897         lockdep_assert_held(&ctx->mutex);
1898 
1899         event->ctx = ctx;
1900         if (event->cpu != -1)
1901                 event->cpu = cpu;
1902 
1903         if (!task) {
1904                 /*
1905                  * Per cpu events are installed via an smp call and
1906                  * the install is always successful.
1907                  */
1908                 cpu_function_call(cpu, __perf_install_in_context, event);
1909                 return;
1910         }
1911 
1912 retry:
1913         if (!task_function_call(task, __perf_install_in_context, event))
1914                 return;
1915 
1916         raw_spin_lock_irq(&ctx->lock);
1917         /*
1918          * If we failed to find a running task, but find the context active now
1919          * that we've acquired the ctx->lock, retry.
1920          */
1921         if (ctx->is_active) {
1922                 raw_spin_unlock_irq(&ctx->lock);
1923                 goto retry;
1924         }
1925 
1926         /*
1927          * Since the task isn't running, its safe to add the event, us holding
1928          * the ctx->lock ensures the task won't get scheduled in.
1929          */
1930         add_event_to_ctx(event, ctx);
1931         raw_spin_unlock_irq(&ctx->lock);
1932 }
1933 
1934 /*
1935  * Put a event into inactive state and update time fields.
1936  * Enabling the leader of a group effectively enables all
1937  * the group members that aren't explicitly disabled, so we
1938  * have to update their ->tstamp_enabled also.
1939  * Note: this works for group members as well as group leaders
1940  * since the non-leader members' sibling_lists will be empty.
1941  */
1942 static void __perf_event_mark_enabled(struct perf_event *event)
1943 {
1944         struct perf_event *sub;
1945         u64 tstamp = perf_event_time(event);
1946 
1947         event->state = PERF_EVENT_STATE_INACTIVE;
1948         event->tstamp_enabled = tstamp - event->total_time_enabled;
1949         list_for_each_entry(sub, &event->sibling_list, group_entry) {
1950                 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1951                         sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1952         }
1953 }
1954 
1955 /*
1956  * Cross CPU call to enable a performance event
1957  */
1958 static int __perf_event_enable(void *info)
1959 {
1960         struct perf_event *event = info;
1961         struct perf_event_context *ctx = event->ctx;
1962         struct perf_event *leader = event->group_leader;
1963         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1964         int err;
1965 
1966         /*
1967          * There's a time window between 'ctx->is_active' check
1968          * in perf_event_enable function and this place having:
1969          *   - IRQs on
1970          *   - ctx->lock unlocked
1971          *
1972          * where the task could be killed and 'ctx' deactivated
1973          * by perf_event_exit_task.
1974          */
1975         if (!ctx->is_active)
1976                 return -EINVAL;
1977 
1978         raw_spin_lock(&ctx->lock);
1979         update_context_time(ctx);
1980 
1981         if (event->state >= PERF_EVENT_STATE_INACTIVE)
1982                 goto unlock;
1983 
1984         /*
1985          * set current task's cgroup time reference point
1986          */
1987         perf_cgroup_set_timestamp(current, ctx);
1988 
1989         __perf_event_mark_enabled(event);
1990 
1991         if (!event_filter_match(event)) {
1992                 if (is_cgroup_event(event))
1993                         perf_cgroup_defer_enabled(event);
1994                 goto unlock;
1995         }
1996 
1997         /*
1998          * If the event is in a group and isn't the group leader,
1999          * then don't put it on unless the group is on.
2000          */
2001         if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
2002                 goto unlock;
2003 
2004         if (!group_can_go_on(event, cpuctx, 1)) {
2005                 err = -EEXIST;
2006         } else {
2007                 if (event == leader)
2008                         err = group_sched_in(event, cpuctx, ctx);
2009                 else
2010                         err = event_sched_in(event, cpuctx, ctx);
2011         }
2012 
2013         if (err) {
2014                 /*
2015                  * If this event can't go on and it's part of a
2016                  * group, then the whole group has to come off.
2017                  */
2018                 if (leader != event) {
2019                         group_sched_out(leader, cpuctx, ctx);
2020                         perf_cpu_hrtimer_restart(cpuctx);
2021                 }
2022                 if (leader->attr.pinned) {
2023                         update_group_times(leader);
2024                         leader->state = PERF_EVENT_STATE_ERROR;
2025                 }
2026         }
2027 
2028 unlock:
2029         raw_spin_unlock(&ctx->lock);
2030 
2031         return 0;
2032 }
2033 
2034 /*
2035  * Enable a event.
2036  *
2037  * If event->ctx is a cloned context, callers must make sure that
2038  * every task struct that event->ctx->task could possibly point to
2039  * remains valid.  This condition is satisfied when called through
2040  * perf_event_for_each_child or perf_event_for_each as described
2041  * for perf_event_disable.
2042  */
2043 void perf_event_enable(struct perf_event *event)
2044 {
2045         struct perf_event_context *ctx = event->ctx;
2046         struct task_struct *task = ctx->task;
2047 
2048         if (!task) {
2049                 /*
2050                  * Enable the event on the cpu that it's on
2051                  */
2052                 cpu_function_call(event->cpu, __perf_event_enable, event);
2053                 return;
2054         }
2055 
2056         raw_spin_lock_irq(&ctx->lock);
2057         if (event->state >= PERF_EVENT_STATE_INACTIVE)
2058                 goto out;
2059 
2060         /*
2061          * If the event is in error state, clear that first.
2062          * That way, if we see the event in error state below, we
2063          * know that it has gone back into error state, as distinct
2064          * from the task having been scheduled away before the
2065          * cross-call arrived.
2066          */
2067         if (event->state == PERF_EVENT_STATE_ERROR)
2068                 event->state = PERF_EVENT_STATE_OFF;
2069 
2070 retry:
2071         if (!ctx->is_active) {
2072                 __perf_event_mark_enabled(event);
2073                 goto out;
2074         }
2075 
2076         raw_spin_unlock_irq(&ctx->lock);
2077 
2078         if (!task_function_call(task, __perf_event_enable, event))
2079                 return;
2080 
2081         raw_spin_lock_irq(&ctx->lock);
2082 
2083         /*
2084          * If the context is active and the event is still off,
2085          * we need to retry the cross-call.
2086          */
2087         if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
2088                 /*
2089                  * task could have been flipped by a concurrent
2090                  * perf_event_context_sched_out()
2091                  */
2092                 task = ctx->task;
2093                 goto retry;
2094         }
2095 
2096 out:
2097         raw_spin_unlock_irq(&ctx->lock);
2098 }
2099 EXPORT_SYMBOL_GPL(perf_event_enable);
2100 
2101 int perf_event_refresh(struct perf_event *event, int refresh)
2102 {
2103         /*
2104          * not supported on inherited events
2105          */
2106         if (event->attr.inherit || !is_sampling_event(event))
2107                 return -EINVAL;
2108 
2109         atomic_add(refresh, &event->event_limit);
2110         perf_event_enable(event);
2111 
2112         return 0;
2113 }
2114 EXPORT_SYMBOL_GPL(perf_event_refresh);
2115 
2116 static void ctx_sched_out(struct perf_event_context *ctx,
2117                           struct perf_cpu_context *cpuctx,
2118                           enum event_type_t event_type)
2119 {
2120         struct perf_event *event;
2121         int is_active = ctx->is_active;
2122 
2123         ctx->is_active &= ~event_type;
2124         if (likely(!ctx->nr_events))
2125                 return;
2126 
2127         update_context_time(ctx);
2128         update_cgrp_time_from_cpuctx(cpuctx);
2129         if (!ctx->nr_active)
2130                 return;
2131 
2132         perf_pmu_disable(ctx->pmu);
2133         if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
2134                 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
2135                         group_sched_out(event, cpuctx, ctx);
2136         }
2137 
2138         if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
2139                 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
2140                         group_sched_out(event, cpuctx, ctx);
2141         }
2142         perf_pmu_enable(ctx->pmu);
2143 }
2144 
2145 /*
2146  * Test whether two contexts are equivalent, i.e. whether they
2147  * have both been cloned from the same version of the same context
2148  * and they both have the same number of enabled events.
2149  * If the number of enabled events is the same, then the set
2150  * of enabled events should be the same, because these are both
2151  * inherited contexts, therefore we can't access individual events
2152  * in them directly with an fd; we can only enable/disable all
2153  * events via prctl, or enable/disable all events in a family
2154  * via ioctl, which will have the same effect on both contexts.
2155  */
2156 static int context_equiv(struct perf_event_context *ctx1,
2157                          struct perf_event_context *ctx2)
2158 {
2159         return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
2160                 && ctx1->parent_gen == ctx2->parent_gen
2161                 && !ctx1->pin_count && !ctx2->pin_count;
2162 }
2163 
2164 static void __perf_event_sync_stat(struct perf_event *event,
2165                                      struct perf_event *next_event)
2166 {
2167         u64 value;
2168 
2169         if (!event->attr.inherit_stat)
2170                 return;
2171 
2172         /*
2173          * Update the event value, we cannot use perf_event_read()
2174          * because we're in the middle of a context switch and have IRQs
2175          * disabled, which upsets smp_call_function_single(), however
2176          * we know the event must be on the current CPU, therefore we
2177          * don't need to use it.
2178          */
2179         switch (event->state) {
2180         case PERF_EVENT_STATE_ACTIVE:
2181                 event->pmu->read(event);
2182                 /* fall-through */
2183 
2184         case PERF_EVENT_STATE_INACTIVE:
2185                 update_event_times(event);
2186                 break;
2187 
2188         default:
2189                 break;
2190         }
2191 
2192         /*
2193          * In order to keep per-task stats reliable we need to flip the event
2194          * values when we flip the contexts.
2195          */
2196         value = local64_read(&next_event->count);
2197         value = local64_xchg(&event->count, value);
2198         local64_set(&next_event->count, value);
2199 
2200         swap(event->total_time_enabled, next_event->total_time_enabled);
2201         swap(event->total_time_running, next_event->total_time_running);
2202 
2203         /*
2204          * Since we swizzled the values, update the user visible data too.
2205          */
2206         perf_event_update_userpage(event);
2207         perf_event_update_userpage(next_event);
2208 }
2209 
2210 #define list_next_entry(pos, member) \
2211         list_entry(pos->member.next, typeof(*pos), member)
2212 
2213 static void perf_event_sync_stat(struct perf_event_context *ctx,
2214                                    struct perf_event_context *next_ctx)
2215 {
2216         struct perf_event *event, *next_event;
2217 
2218         if (!ctx->nr_stat)
2219                 return;
2220 
2221         update_context_time(ctx);
2222 
2223         event = list_first_entry(&ctx->event_list,
2224                                    struct perf_event, event_entry);
2225 
2226         next_event = list_first_entry(&next_ctx->event_list,
2227                                         struct perf_event, event_entry);
2228 
2229         while (&event->event_entry != &ctx->event_list &&
2230                &next_event->event_entry != &next_ctx->event_list) {
2231 
2232                 __perf_event_sync_stat(event, next_event);
2233 
2234                 event = list_next_entry(event, event_entry);
2235                 next_event = list_next_entry(next_event, event_entry);
2236         }
2237 }
2238 
2239 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
2240                                          struct task_struct *next)
2241 {
2242         struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
2243         struct perf_event_context *next_ctx;
2244         struct perf_event_context *parent;
2245         struct perf_cpu_context *cpuctx;
2246         int do_switch = 1;
2247 
2248         if (likely(!ctx))
2249                 return;
2250 
2251         cpuctx = __get_cpu_context(ctx);
2252         if (!cpuctx->task_ctx)
2253                 return;
2254 
2255         rcu_read_lock();
2256         parent = rcu_dereference(ctx->parent_ctx);
2257         next_ctx = next->perf_event_ctxp[ctxn];
2258         if (parent && next_ctx &&
2259             rcu_dereference(next_ctx->parent_ctx) == parent) {
2260                 /*
2261                  * Looks like the two contexts are clones, so we might be
2262                  * able to optimize the context switch.  We lock both
2263                  * contexts and check that they are clones under the
2264                  * lock (including re-checking that neither has been
2265                  * uncloned in the meantime).  It doesn't matter which
2266                  * order we take the locks because no other cpu could
2267                  * be trying to lock both of these tasks.
2268                  */
2269                 raw_spin_lock(&ctx->lock);
2270                 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
2271                 if (context_equiv(ctx, next_ctx)) {
2272                         /*
2273                          * XXX do we need a memory barrier of sorts
2274                          * wrt to rcu_dereference() of perf_event_ctxp
2275                          */
2276                         task->perf_event_ctxp[ctxn] = next_ctx;
2277                         next->perf_event_ctxp[ctxn] = ctx;
2278                         ctx->task = next;
2279                         next_ctx->task = task;
2280                         do_switch = 0;
2281 
2282                         perf_event_sync_stat(ctx, next_ctx);
2283                 }
2284                 raw_spin_unlock(&next_ctx->lock);
2285                 raw_spin_unlock(&ctx->lock);
2286         }
2287         rcu_read_unlock();
2288 
2289         if (do_switch) {
2290                 raw_spin_lock(&ctx->lock);
2291                 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2292                 cpuctx->task_ctx = NULL;
2293                 raw_spin_unlock(&ctx->lock);
2294         }
2295 }
2296 
2297 #define for_each_task_context_nr(ctxn)                                  \
2298         for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2299 
2300 /*
2301  * Called from scheduler to remove the events of the current task,
2302  * with interrupts disabled.
2303  *
2304  * We stop each event and update the event value in event->count.
2305  *
2306  * This does not protect us against NMI, but disable()
2307  * sets the disabled bit in the control field of event _before_
2308  * accessing the event control register. If a NMI hits, then it will
2309  * not restart the event.
2310  */
2311 void __perf_event_task_sched_out(struct task_struct *task,
2312                                  struct task_struct *next)
2313 {
2314         int ctxn;
2315 
2316         for_each_task_context_nr(ctxn)
2317                 perf_event_context_sched_out(task, ctxn, next);
2318 
2319         /*
2320          * if cgroup events exist on this CPU, then we need
2321          * to check if we have to switch out PMU state.
2322          * cgroup event are system-wide mode only
2323          */
2324         if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2325                 perf_cgroup_sched_out(task, next);
2326 }
2327 
2328 static void task_ctx_sched_out(struct perf_event_context *ctx)
2329 {
2330         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2331 
2332         if (!cpuctx->task_ctx)
2333                 return;
2334 
2335         if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2336                 return;
2337 
2338         ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2339         cpuctx->task_ctx = NULL;
2340 }
2341 
2342 /*
2343  * Called with IRQs disabled
2344  */
2345 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2346                               enum event_type_t event_type)
2347 {
2348         ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2349 }
2350 
2351 static void
2352 ctx_pinned_sched_in(struct perf_event_context *ctx,
2353                     struct perf_cpu_context *cpuctx)
2354 {
2355         struct perf_event *event;
2356 
2357         list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2358                 if (event->state <= PERF_EVENT_STATE_OFF)
2359                         continue;
2360                 if (!event_filter_match(event))
2361                         continue;
2362 
2363                 /* may need to reset tstamp_enabled */
2364                 if (is_cgroup_event(event))
2365                         perf_cgroup_mark_enabled(event, ctx);
2366 
2367                 if (group_can_go_on(event, cpuctx, 1))
2368                         group_sched_in(event, cpuctx, ctx);
2369 
2370                 /*
2371                  * If this pinned group hasn't been scheduled,
2372                  * put it in error state.
2373                  */
2374                 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2375                         update_group_times(event);
2376                         event->state = PERF_EVENT_STATE_ERROR;
2377                 }
2378         }
2379 }
2380 
2381 static void
2382 ctx_flexible_sched_in(struct perf_event_context *ctx,
2383                       struct perf_cpu_context *cpuctx)
2384 {
2385         struct perf_event *event;
2386         int can_add_hw = 1;
2387 
2388         list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2389                 /* Ignore events in OFF or ERROR state */
2390                 if (event->state <= PERF_EVENT_STATE_OFF)
2391                         continue;
2392                 /*
2393                  * Listen to the 'cpu' scheduling filter constraint
2394                  * of events:
2395                  */
2396                 if (!event_filter_match(event))
2397                         continue;
2398 
2399                 /* may need to reset tstamp_enabled */
2400                 if (is_cgroup_event(event))
2401                         perf_cgroup_mark_enabled(event, ctx);
2402 
2403                 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2404                         if (group_sched_in(event, cpuctx, ctx))
2405                                 can_add_hw = 0;
2406                 }
2407         }
2408 }
2409 
2410 static void
2411 ctx_sched_in(struct perf_event_context *ctx,
2412              struct perf_cpu_context *cpuctx,
2413              enum event_type_t event_type,
2414              struct task_struct *task)
2415 {
2416         u64 now;
2417         int is_active = ctx->is_active;
2418 
2419         ctx->is_active |= event_type;
2420         if (likely(!ctx->nr_events))
2421                 return;
2422 
2423         now = perf_clock();
2424         ctx->timestamp = now;
2425         perf_cgroup_set_timestamp(task, ctx);
2426         /*
2427          * First go through the list and put on any pinned groups
2428          * in order to give them the best chance of going on.
2429          */
2430         if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2431                 ctx_pinned_sched_in(ctx, cpuctx);
2432 
2433         /* Then walk through the lower prio flexible groups */
2434         if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2435                 ctx_flexible_sched_in(ctx, cpuctx);
2436 }
2437 
2438 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2439                              enum event_type_t event_type,
2440                              struct task_struct *task)
2441 {
2442         struct perf_event_context *ctx = &cpuctx->ctx;
2443 
2444         ctx_sched_in(ctx, cpuctx, event_type, task);
2445 }
2446 
2447 static void perf_event_context_sched_in(struct perf_event_context *ctx,
2448                                         struct task_struct *task)
2449 {
2450         struct perf_cpu_context *cpuctx;
2451 
2452         cpuctx = __get_cpu_context(ctx);
2453         if (cpuctx->task_ctx == ctx)
2454                 return;
2455 
2456         perf_ctx_lock(cpuctx, ctx);
2457         perf_pmu_disable(ctx->pmu);
2458         /*
2459          * We want to keep the following priority order:
2460          * cpu pinned (that don't need to move), task pinned,
2461          * cpu flexible, task flexible.
2462          */
2463         cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2464 
2465         if (ctx->nr_events)
2466                 cpuctx->task_ctx = ctx;
2467 
2468         perf_event_sched_in(cpuctx, cpuctx->task_ctx, task);
2469 
2470         perf_pmu_enable(ctx->pmu);
2471         perf_ctx_unlock(cpuctx, ctx);
2472 
2473         /*
2474          * Since these rotations are per-cpu, we need to ensure the
2475          * cpu-context we got scheduled on is actually rotating.
2476          */
2477         perf_pmu_rotate_start(ctx->pmu);
2478 }
2479 
2480 /*
2481  * When sampling the branck stack in system-wide, it may be necessary
2482  * to flush the stack on context switch. This happens when the branch
2483  * stack does not tag its entries with the pid of the current task.
2484  * Otherwise it becomes impossible to associate a branch entry with a
2485  * task. This ambiguity is more likely to appear when the branch stack
2486  * supports priv level filtering and the user sets it to monitor only
2487  * at the user level (which could be a useful measurement in system-wide
2488  * mode). In that case, the risk is high of having a branch stack with
2489  * branch from multiple tasks. Flushing may mean dropping the existing
2490  * entries or stashing them somewhere in the PMU specific code layer.
2491  *
2492  * This function provides the context switch callback to the lower code
2493  * layer. It is invoked ONLY when there is at least one system-wide context
2494  * with at least one active event using taken branch sampling.
2495  */
2496 static void perf_branch_stack_sched_in(struct task_struct *prev,
2497                                        struct task_struct *task)
2498 {
2499         struct perf_cpu_context *cpuctx;
2500         struct pmu *pmu;
2501         unsigned long flags;
2502 
2503         /* no need to flush branch stack if not changing task */
2504         if (prev == task)
2505                 return;
2506 
2507         local_irq_save(flags);
2508 
2509         rcu_read_lock();
2510 
2511         list_for_each_entry_rcu(pmu, &pmus, entry) {
2512                 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2513 
2514                 /*
2515                  * check if the context has at least one
2516                  * event using PERF_SAMPLE_BRANCH_STACK
2517                  */
2518                 if (cpuctx->ctx.nr_branch_stack > 0
2519                     && pmu->flush_branch_stack) {
2520 
2521                         pmu = cpuctx->ctx.pmu;
2522 
2523                         perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2524 
2525                         perf_pmu_disable(pmu);
2526 
2527                         pmu->flush_branch_stack();
2528 
2529                         perf_pmu_enable(pmu);
2530 
2531                         perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2532                 }
2533         }
2534 
2535         rcu_read_unlock();
2536 
2537         local_irq_restore(flags);
2538 }
2539 
2540 /*
2541  * Called from scheduler to add the events of the current task
2542  * with interrupts disabled.
2543  *
2544  * We restore the event value and then enable it.
2545  *
2546  * This does not protect us against NMI, but enable()
2547  * sets the enabled bit in the control field of event _before_
2548  * accessing the event control register. If a NMI hits, then it will
2549  * keep the event running.
2550  */
2551 void __perf_event_task_sched_in(struct task_struct *prev,
2552                                 struct task_struct *task)
2553 {
2554         struct perf_event_context *ctx;
2555         int ctxn;
2556 
2557         for_each_task_context_nr(ctxn) {
2558                 ctx = task->perf_event_ctxp[ctxn];
2559                 if (likely(!ctx))
2560                         continue;
2561 
2562                 perf_event_context_sched_in(ctx, task);
2563         }
2564         /*
2565          * if cgroup events exist on this CPU, then we need
2566          * to check if we have to switch in PMU state.
2567          * cgroup event are system-wide mode only
2568          */
2569         if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2570                 perf_cgroup_sched_in(prev, task);
2571 
2572         /* check for system-wide branch_stack events */
2573         if (atomic_read(&__get_cpu_var(perf_branch_stack_events)))
2574                 perf_branch_stack_sched_in(prev, task);
2575 }
2576 
2577 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2578 {
2579         u64 frequency = event->attr.sample_freq;
2580         u64 sec = NSEC_PER_SEC;
2581         u64 divisor, dividend;
2582 
2583         int count_fls, nsec_fls, frequency_fls, sec_fls;
2584 
2585         count_fls = fls64(count);
2586         nsec_fls = fls64(nsec);
2587         frequency_fls = fls64(frequency);
2588         sec_fls = 30;
2589 
2590         /*
2591          * We got @count in @nsec, with a target of sample_freq HZ
2592          * the target period becomes:
2593          *
2594          *             @count * 10^9
2595          * period = -------------------
2596          *          @nsec * sample_freq
2597          *
2598          */
2599 
2600         /*
2601          * Reduce accuracy by one bit such that @a and @b converge
2602          * to a similar magnitude.
2603          */
2604 #define REDUCE_FLS(a, b)                \
2605 do {                                    \
2606         if (a##_fls > b##_fls) {        \
2607                 a >>= 1;                \
2608                 a##_fls--;              \
2609         } else {                        \
2610                 b >>= 1;                \
2611                 b##_fls--;              \
2612         }                               \
2613 } while (0)
2614 
2615         /*
2616          * Reduce accuracy until either term fits in a u64, then proceed with
2617          * the other, so that finally we can do a u64/u64 division.
2618          */
2619         while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2620                 REDUCE_FLS(nsec, frequency);
2621                 REDUCE_FLS(sec, count);
2622         }
2623 
2624         if (count_fls + sec_fls > 64) {
2625                 divisor = nsec * frequency;
2626 
2627                 while (count_fls + sec_fls > 64) {
2628                         REDUCE_FLS(count, sec);
2629                         divisor >>= 1;
2630                 }
2631 
2632                 dividend = count * sec;
2633         } else {
2634                 dividend = count * sec;
2635 
2636                 while (nsec_fls + frequency_fls > 64) {
2637                         REDUCE_FLS(nsec, frequency);
2638                         dividend >>= 1;
2639                 }
2640 
2641                 divisor = nsec * frequency;
2642         }
2643 
2644         if (!divisor)
2645                 return dividend;
2646 
2647         return div64_u64(dividend, divisor);
2648 }
2649 
2650 static DEFINE_PER_CPU(int, perf_throttled_count);
2651 static DEFINE_PER_CPU(u64, perf_throttled_seq);
2652 
2653 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
2654 {
2655         struct hw_perf_event *hwc = &event->hw;
2656         s64 period, sample_period;
2657         s64 delta;
2658 
2659         period = perf_calculate_period(event, nsec, count);
2660 
2661         delta = (s64)(period - hwc->sample_period);
2662         delta = (delta + 7) / 8; /* low pass filter */
2663 
2664         sample_period = hwc->sample_period + delta;
2665 
2666         if (!sample_period)
2667                 sample_period = 1;
2668 
2669         hwc->sample_period = sample_period;
2670 
2671         if (local64_read(&hwc->period_left) > 8*sample_period) {
2672                 if (disable)
2673                         event->pmu->stop(event, PERF_EF_UPDATE);
2674 
2675                 local64_set(&hwc->period_left, 0);
2676 
2677                 if (disable)
2678                         event->pmu->start(event, PERF_EF_RELOAD);
2679         }
2680 }
2681 
2682 /*
2683  * combine freq adjustment with unthrottling to avoid two passes over the
2684  * events. At the same time, make sure, having freq events does not change
2685  * the rate of unthrottling as that would introduce bias.
2686  */
2687 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
2688                                            int needs_unthr)
2689 {
2690         struct perf_event *event;
2691         struct hw_perf_event *hwc;
2692         u64 now, period = TICK_NSEC;
2693         s64 delta;
2694 
2695         /*
2696          * only need to iterate over all events iff:
2697          * - context have events in frequency mode (needs freq adjust)
2698          * - there are events to unthrottle on this cpu
2699          */
2700         if (!(ctx->nr_freq || needs_unthr))
2701                 return;
2702 
2703         raw_spin_lock(&ctx->lock);
2704         perf_pmu_disable(ctx->pmu);
2705 
2706         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2707                 if (event->state != PERF_EVENT_STATE_ACTIVE)
2708                         continue;
2709 
2710                 if (!event_filter_match(event))
2711                         continue;
2712 
2713                 hwc = &event->hw;
2714 
2715                 if (needs_unthr && hwc->interrupts == MAX_INTERRUPTS) {
2716                         hwc->interrupts = 0;
2717                         perf_log_throttle(event, 1);
2718                         event->pmu->start(event, 0);
2719                 }
2720 
2721                 if (!event->attr.freq || !event->attr.sample_freq)
2722                         continue;
2723 
2724                 /*
2725                  * stop the event and update event->count
2726                  */
2727                 event->pmu->stop(event, PERF_EF_UPDATE);
2728 
2729                 now = local64_read(&event->count);
2730                 delta = now - hwc->freq_count_stamp;
2731                 hwc->freq_count_stamp = now;
2732 
2733                 /*
2734                  * restart the event
2735                  * reload only if value has changed
2736                  * we have stopped the event so tell that
2737                  * to perf_adjust_period() to avoid stopping it
2738                  * twice.
2739                  */
2740                 if (delta > 0)
2741                         perf_adjust_period(event, period, delta, false);
2742 
2743                 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
2744         }
2745 
2746         perf_pmu_enable(ctx->pmu);
2747         raw_spin_unlock(&ctx->lock);
2748 }
2749 
2750 /*
2751  * Round-robin a context's events:
2752  */
2753 static void rotate_ctx(struct perf_event_context *ctx)
2754 {
2755         /*
2756          * Rotate the first entry last of non-pinned groups. Rotation might be
2757          * disabled by the inheritance code.
2758          */
2759         if (!ctx->rotate_disable)
2760                 list_rotate_left(&ctx->flexible_groups);
2761 }
2762 
2763 /*
2764  * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2765  * because they're strictly cpu affine and rotate_start is called with IRQs
2766  * disabled, while rotate_context is called from IRQ context.
2767  */
2768 static int perf_rotate_context(struct perf_cpu_context *cpuctx)
2769 {
2770         struct perf_event_context *ctx = NULL;
2771         int rotate = 0, remove = 1;
2772 
2773         if (cpuctx->ctx.nr_events) {
2774                 remove = 0;
2775                 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
2776                         rotate = 1;
2777         }
2778 
2779         ctx = cpuctx->task_ctx;
2780         if (ctx && ctx->nr_events) {
2781                 remove = 0;
2782                 if (ctx->nr_events != ctx->nr_active)
2783                         rotate = 1;
2784         }
2785 
2786         if (!rotate)
2787                 goto done;
2788 
2789         perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2790         perf_pmu_disable(cpuctx->ctx.pmu);
2791 
2792         cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2793         if (ctx)
2794                 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
2795 
2796         rotate_ctx(&cpuctx->ctx);
2797         if (ctx)
2798                 rotate_ctx(ctx);
2799 
2800         perf_event_sched_in(cpuctx, ctx, current);
2801 
2802         perf_pmu_enable(cpuctx->ctx.pmu);
2803         perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2804 done:
2805         if (remove)
2806                 list_del_init(&cpuctx->rotation_list);
2807 
2808         return rotate;
2809 }
2810 
2811 #ifdef CONFIG_NO_HZ_FULL
2812 bool perf_event_can_stop_tick(void)
2813 {
2814         if (list_empty(&__get_cpu_var(rotation_list)))
2815                 return true;
2816         else
2817                 return false;
2818 }
2819 #endif
2820 
2821 void perf_event_task_tick(void)
2822 {
2823         struct list_head *head = &__get_cpu_var(rotation_list);
2824         struct perf_cpu_context *cpuctx, *tmp;
2825         struct perf_event_context *ctx;
2826         int throttled;
2827 
2828         WARN_ON(!irqs_disabled());
2829 
2830         __this_cpu_inc(perf_throttled_seq);
2831         throttled = __this_cpu_xchg(perf_throttled_count, 0);
2832 
2833         list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2834                 ctx = &cpuctx->ctx;
2835                 perf_adjust_freq_unthr_context(ctx, throttled);
2836 
2837                 ctx = cpuctx->task_ctx;
2838                 if (ctx)
2839                         perf_adjust_freq_unthr_context(ctx, throttled);
2840         }
2841 }
2842 
2843 static int event_enable_on_exec(struct perf_event *event,
2844                                 struct perf_event_context *ctx)
2845 {
2846         if (!event->attr.enable_on_exec)
2847                 return 0;
2848 
2849         event->attr.enable_on_exec = 0;
2850         if (event->state >= PERF_EVENT_STATE_INACTIVE)
2851                 return 0;
2852 
2853         __perf_event_mark_enabled(event);
2854 
2855         return 1;
2856 }
2857 
2858 /*
2859  * Enable all of a task's events that have been marked enable-on-exec.
2860  * This expects task == current.
2861  */
2862 static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2863 {
2864         struct perf_event *event;
2865         unsigned long flags;
2866         int enabled = 0;
2867         int ret;
2868 
2869         local_irq_save(flags);
2870         if (!ctx || !ctx->nr_events)
2871                 goto out;
2872 
2873         /*
2874          * We must ctxsw out cgroup events to avoid conflict
2875          * when invoking perf_task_event_sched_in() later on
2876          * in this function. Otherwise we end up trying to
2877          * ctxswin cgroup events which are already scheduled
2878          * in.
2879          */
2880         perf_cgroup_sched_out(current, NULL);
2881 
2882         raw_spin_lock(&ctx->lock);
2883         task_ctx_sched_out(ctx);
2884 
2885         list_for_each_entry(event, &ctx->event_list, event_entry) {
2886                 ret = event_enable_on_exec(event, ctx);
2887                 if (ret)
2888                         enabled = 1;
2889         }
2890 
2891         /*
2892          * Unclone this context if we enabled any event.
2893          */
2894         if (enabled)
2895                 unclone_ctx(ctx);
2896 
2897         raw_spin_unlock(&ctx->lock);
2898 
2899         /*
2900          * Also calls ctxswin for cgroup events, if any:
2901          */
2902         perf_event_context_sched_in(ctx, ctx->task);
2903 out:
2904         local_irq_restore(flags);
2905 }
2906 
2907 /*
2908  * Cross CPU call to read the hardware event
2909  */
2910 static void __perf_event_read(void *info)
2911 {
2912         struct perf_event *event = info;
2913         struct perf_event_context *ctx = event->ctx;
2914         struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2915 
2916         /*
2917          * If this is a task context, we need to check whether it is
2918          * the current task context of this cpu.  If not it has been
2919          * scheduled out before the smp call arrived.  In that case
2920          * event->count would have been updated to a recent sample
2921          * when the event was scheduled out.
2922          */
2923         if (ctx->task && cpuctx->task_ctx != ctx)
2924                 return;
2925 
2926         raw_spin_lock(&ctx->lock);
2927         if (ctx->is_active) {
2928                 update_context_time(ctx);
2929                 update_cgrp_time_from_event(event);
2930         }
2931         update_event_times(event);
2932         if (event->state == PERF_EVENT_STATE_ACTIVE)
2933                 event->pmu->read(event);
2934         raw_spin_unlock(&ctx->lock);
2935 }
2936 
2937 static inline u64 perf_event_count(struct perf_event *event)
2938 {
2939         return local64_read(&event->count) + atomic64_read(&event->child_count);
2940 }
2941 
2942 static u64 perf_event_read(struct perf_event *event)
2943 {
2944         /*
2945          * If event is enabled and currently active on a CPU, update the
2946          * value in the event structure:
2947          */
2948         if (event->state == PERF_EVENT_STATE_ACTIVE) {
2949                 smp_call_function_single(event->oncpu,
2950                                          __perf_event_read, event, 1);
2951         } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
2952                 struct perf_event_context *ctx = event->ctx;
2953                 unsigned long flags;
2954 
2955                 raw_spin_lock_irqsave(&ctx->lock, flags);
2956                 /*
2957                  * may read while context is not active
2958                  * (e.g., thread is blocked), in that case
2959                  * we cannot update context time
2960                  */
2961                 if (ctx->is_active) {
2962                         update_context_time(ctx);
2963                         update_cgrp_time_from_event(event);
2964                 }
2965                 update_event_times(event);
2966                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2967         }
2968 
2969         return perf_event_count(event);
2970 }
2971 
2972 /*
2973  * Initialize the perf_event context in a task_struct:
2974  */
2975 static void __perf_event_init_context(struct perf_event_context *ctx)
2976 {
2977         raw_spin_lock_init(&ctx->lock);
2978         mutex_init(&ctx->mutex);
2979         INIT_LIST_HEAD(&ctx->pinned_groups);
2980         INIT_LIST_HEAD(&ctx->flexible_groups);
2981         INIT_LIST_HEAD(&ctx->event_list);
2982         atomic_set(&ctx->refcount, 1);
2983 }
2984 
2985 static struct perf_event_context *
2986 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2987 {
2988         struct perf_event_context *ctx;
2989 
2990         ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2991         if (!ctx)
2992                 return NULL;
2993 
2994         __perf_event_init_context(ctx);
2995         if (task) {
2996                 ctx->task = task;
2997                 get_task_struct(task);
2998         }
2999         ctx->pmu = pmu;
3000 
3001         return ctx;
3002 }
3003 
3004 static struct task_struct *
3005 find_lively_task_by_vpid(pid_t vpid)
3006 {
3007         struct task_struct *task;
3008         int err;
3009 
3010         rcu_read_lock();
3011         if (!vpid)
3012                 task = current;
3013         else
3014                 task = find_task_by_vpid(vpid);
3015         if (task)
3016                 get_task_struct(task);
3017         rcu_read_unlock();
3018 
3019         if (!task)
3020                 return ERR_PTR(-ESRCH);
3021 
3022         /* Reuse ptrace permission checks for now. */
3023         err = -EACCES;
3024         if (!ptrace_may_access(task, PTRACE_MODE_READ))
3025                 goto errout;
3026 
3027         return task;
3028 errout:
3029         put_task_struct(task);
3030         return ERR_PTR(err);
3031 
3032 }
3033 
3034 /*
3035  * Returns a matching context with refcount and pincount.
3036  */
3037 static struct perf_event_context *
3038 find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
3039 {
3040         struct perf_event_context *ctx;
3041         struct perf_cpu_context *cpuctx;
3042         unsigned long flags;
3043         int ctxn, err;
3044 
3045         if (!task) {
3046                 /* Must be root to operate on a CPU event: */
3047                 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
3048                         return ERR_PTR(-EACCES);
3049 
3050                 /*
3051                  * We could be clever and allow to attach a event to an
3052                  * offline CPU and activate it when the CPU comes up, but
3053                  * that's for later.
3054                  */
3055                 if (!cpu_online(cpu))
3056                         return ERR_PTR(-ENODEV);
3057 
3058                 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
3059                 ctx = &cpuctx->ctx;
3060                 get_ctx(ctx);
3061                 ++ctx->pin_count;
3062 
3063                 return ctx;
3064         }
3065 
3066         err = -EINVAL;
3067         ctxn = pmu->task_ctx_nr;
3068         if (ctxn < 0)
3069                 goto errout;
3070 
3071 retry:
3072         ctx = perf_lock_task_context(task, ctxn, &flags);
3073         if (ctx) {
3074                 unclone_ctx(ctx);
3075                 ++ctx->pin_count;
3076                 raw_spin_unlock_irqrestore(&ctx->lock, flags);
3077         } else {
3078                 ctx = alloc_perf_context(pmu, task);
3079                 err = -ENOMEM;
3080                 if (!ctx)
3081                         goto errout;
3082 
3083                 err = 0;
3084                 mutex_lock(&task->perf_event_mutex);
3085                 /*
3086                  * If it has already passed perf_event_exit_task().
3087                  * we must see PF_EXITING, it takes this mutex too.
3088                  */
3089                 if (task->flags & PF_EXITING)
3090                         err = -ESRCH;
3091                 else if (task->perf_event_ctxp[ctxn])
3092                         err = -EAGAIN;
3093                 else {
3094                         get_ctx(ctx);
3095                         ++ctx->pin_count;
3096                         rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
3097                 }
3098                 mutex_unlock(&task->perf_event_mutex);
3099 
3100                 if (unlikely(err)) {
3101                         put_ctx(ctx);
3102 
3103                         if (err == -EAGAIN)
3104                                 goto retry;
3105                         goto errout;
3106                 }
3107         }
3108 
3109         return ctx;
3110 
3111 errout:
3112         return ERR_PTR(err);
3113 }
3114 
3115 static void perf_event_free_filter(struct perf_event *event);
3116 
3117 static void free_event_rcu(struct rcu_head *head)
3118 {
3119         struct perf_event *event;
3120 
3121         event = container_of(head, struct perf_event, rcu_head);
3122         if (event->ns)
3123                 put_pid_ns(event->ns);
3124         perf_event_free_filter(event);
3125         kfree(event);
3126 }
3127 
3128 static void ring_buffer_put(struct ring_buffer *rb);
3129 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb);
3130 
3131 static void free_event(struct perf_event *event)
3132 {
3133         irq_work_sync(&event->pending);
3134 
3135         if (!event->parent) {
3136                 if (event->attach_state & PERF_ATTACH_TASK)
3137                         static_key_slow_dec_deferred(&perf_sched_events);
3138                 if (event->attr.mmap || event->attr.mmap_data)
3139                         atomic_dec(&nr_mmap_events);
3140                 if (event->attr.comm)
3141                         atomic_dec(&nr_comm_events);
3142                 if (event->attr.task)
3143                         atomic_dec(&nr_task_events);
3144                 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
3145                         put_callchain_buffers();
3146                 if (is_cgroup_event(event)) {
3147                         atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
3148                         static_key_slow_dec_deferred(&perf_sched_events);
3149                 }
3150 
3151                 if (has_branch_stack(event)) {
3152                         static_key_slow_dec_deferred(&perf_sched_events);
3153                         /* is system-wide event */
3154                         if (!(event->attach_state & PERF_ATTACH_TASK)) {
3155                                 atomic_dec(&per_cpu(perf_branch_stack_events,
3156                                                     event->cpu));
3157                         }
3158                 }
3159         }
3160 
3161         if (event->rb) {
3162                 struct ring_buffer *rb;
3163 
3164                 /*
3165                  * Can happen when we close an event with re-directed output.
3166                  *
3167                  * Since we have a 0 refcount, perf_mmap_close() will skip
3168                  * over us; possibly making our ring_buffer_put() the last.
3169                  */
3170                 mutex_lock(&event->mmap_mutex);
3171                 rb = event->rb;
3172                 if (rb) {
3173                         rcu_assign_pointer(event->rb, NULL);
3174                         ring_buffer_detach(event, rb);
3175                         ring_buffer_put(rb); /* could be last */
3176                 }
3177                 mutex_unlock(&event->mmap_mutex);
3178         }
3179 
3180         if (is_cgroup_event(event))
3181                 perf_detach_cgroup(event);
3182 
3183         if (event->destroy)
3184                 event->destroy(event);
3185 
3186         if (event->ctx)
3187                 put_ctx(event->ctx);
3188 
3189         call_rcu(&event->rcu_head, free_event_rcu);
3190 }
3191 
3192 int perf_event_release_kernel(struct perf_event *event)
3193 {
3194         struct perf_event_context *ctx = event->ctx;
3195 
3196         WARN_ON_ONCE(ctx->parent_ctx);
3197         /*
3198          * There are two ways this annotation is useful:
3199          *
3200          *  1) there is a lock recursion from perf_event_exit_task
3201          *     see the comment there.
3202          *
3203          *  2) there is a lock-inversion with mmap_sem through
3204          *     perf_event_read_group(), which takes faults while
3205          *     holding ctx->mutex, however this is called after
3206          *     the last filedesc died, so there is no possibility
3207          *     to trigger the AB-BA case.
3208          */
3209         mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
3210         raw_spin_lock_irq(&ctx->lock);
3211         perf_group_detach(event);
3212         raw_spin_unlock_irq(&ctx->lock);
3213         perf_remove_from_context(event);
3214         mutex_unlock(&ctx->mutex);
3215 
3216         free_event(event);
3217 
3218         return 0;
3219 }
3220 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3221 
3222 /*
3223  * Called when the last reference to the file is gone.
3224  */
3225 static void put_event(struct perf_event *event)
3226 {
3227         struct task_struct *owner;
3228 
3229         if (!atomic_long_dec_and_test(&event->refcount))
3230                 return;
3231 
3232         rcu_read_lock();
3233         owner = ACCESS_ONCE(event->owner);
3234         /*
3235          * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3236          * !owner it means the list deletion is complete and we can indeed
3237          * free this event, otherwise we need to serialize on
3238          * owner->perf_event_mutex.
3239          */
3240         smp_read_barrier_depends();
3241         if (owner) {
3242                 /*
3243                  * Since delayed_put_task_struct() also drops the last
3244                  * task reference we can safely take a new reference
3245                  * while holding the rcu_read_lock().
3246                  */
3247                 get_task_struct(owner);
3248         }
3249         rcu_read_unlock();
3250 
3251         if (owner) {
3252                 mutex_lock(&owner->perf_event_mutex);
3253                 /*
3254                  * We have to re-check the event->owner field, if it is cleared
3255                  * we raced with perf_event_exit_task(), acquiring the mutex
3256                  * ensured they're done, and we can proceed with freeing the
3257                  * event.
3258                  */
3259                 if (event->owner)
3260                         list_del_init(&event->owner_entry);
3261                 mutex_unlock(&owner->perf_event_mutex);
3262                 put_task_struct(owner);
3263         }
3264 
3265         perf_event_release_kernel(event);
3266 }
3267 
3268 static int perf_release(struct inode *inode, struct file *file)
3269 {
3270         put_event(file->private_data);
3271         return 0;
3272 }
3273 
3274 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3275 {
3276         struct perf_event *child;
3277         u64 total = 0;
3278 
3279         *enabled = 0;
3280         *running = 0;
3281 
3282         mutex_lock(&event->child_mutex);
3283         total += perf_event_read(event);
3284         *enabled += event->total_time_enabled +
3285                         atomic64_read(&event->child_total_time_enabled);
3286         *running += event->total_time_running +
3287                         atomic64_read(&event->child_total_time_running);
3288 
3289         list_for_each_entry(child, &event->child_list, child_list) {
3290                 total += perf_event_read(child);
3291                 *enabled += child->total_time_enabled;
3292                 *running += child->total_time_running;
3293         }
3294         mutex_unlock(&event->child_mutex);
3295 
3296         return total;
3297 }
3298 EXPORT_SYMBOL_GPL(perf_event_read_value);
3299 
3300 static int perf_event_read_group(struct perf_event *event,
3301                                    u64 read_format, char __user *buf)
3302 {
3303         struct perf_event *leader = event->group_leader, *sub;
3304         int n = 0, size = 0, ret = -EFAULT;
3305         struct perf_event_context *ctx = leader->ctx;
3306         u64 values[5];
3307         u64 count, enabled, running;
3308 
3309         mutex_lock(&ctx->mutex);
3310         count = perf_event_read_value(leader, &enabled, &running);
3311 
3312         values[n++] = 1 + leader->nr_siblings;
3313         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3314                 values[n++] = enabled;
3315         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3316                 values[n++] = running;
3317         values[n++] = count;
3318         if (read_format & PERF_FORMAT_ID)
3319                 values[n++] = primary_event_id(leader);
3320 
3321         size = n * sizeof(u64);
3322 
3323         if (copy_to_user(buf, values, size))
3324                 goto unlock;
3325 
3326         ret = size;
3327 
3328         list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3329                 n = 0;
3330 
3331                 values[n++] = perf_event_read_value(sub, &enabled, &running);
3332                 if (read_format & PERF_FORMAT_ID)
3333                         values[n++] = primary_event_id(sub);
3334 
3335                 size = n * sizeof(u64);
3336 
3337                 if (copy_to_user(buf + ret, values, size)) {
3338                         ret = -EFAULT;
3339                         goto unlock;
3340                 }
3341 
3342                 ret += size;
3343         }
3344 unlock:
3345         mutex_unlock(&ctx->mutex);
3346 
3347         return ret;
3348 }
3349 
3350 static int perf_event_read_one(struct perf_event *event,
3351                                  u64 read_format, char __user *buf)
3352 {
3353         u64 enabled, running;
3354         u64 values[4];
3355         int n = 0;
3356 
3357         values[n++] = perf_event_read_value(event, &enabled, &running);
3358         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3359                 values[n++] = enabled;
3360         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3361                 values[n++] = running;
3362         if (read_format & PERF_FORMAT_ID)
3363                 values[n++] = primary_event_id(event);
3364 
3365         if (copy_to_user(buf, values, n * sizeof(u64)))
3366                 return -EFAULT;
3367 
3368         return n * sizeof(u64);
3369 }
3370 
3371 /*
3372  * Read the performance event - simple non blocking version for now
3373  */
3374 static ssize_t
3375 perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3376 {
3377         u64 read_format = event->attr.read_format;
3378         int ret;
3379 
3380         /*
3381          * Return end-of-file for a read on a event that is in
3382          * error state (i.e. because it was pinned but it couldn't be
3383          * scheduled on to the CPU at some point).
3384          */
3385         if (event->state == PERF_EVENT_STATE_ERROR)
3386                 return 0;
3387 
3388         if (count < event->read_size)
3389                 return -ENOSPC;
3390 
3391         WARN_ON_ONCE(event->ctx->parent_ctx);
3392         if (read_format & PERF_FORMAT_GROUP)
3393                 ret = perf_event_read_group(event, read_format, buf);
3394         else
3395                 ret = perf_event_read_one(event, read_format, buf);
3396 
3397         return ret;
3398 }
3399 
3400 static ssize_t
3401 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3402 {
3403         struct perf_event *event = file->private_data;
3404 
3405         return perf_read_hw(event, buf, count);
3406 }
3407 
3408 static unsigned int perf_poll(struct file *file, poll_table *wait)
3409 {
3410         struct perf_event *event = file->private_data;
3411         struct ring_buffer *rb;
3412         unsigned int events = POLL_HUP;
3413 
3414         /*
3415          * Pin the event->rb by taking event->mmap_mutex; otherwise
3416          * perf_event_set_output() can swizzle our rb and make us miss wakeups.
3417          */
3418         mutex_lock(&event->mmap_mutex);
3419         rb = event->rb;
3420         if (rb)
3421                 events = atomic_xchg(&rb->poll, 0);
3422         mutex_unlock(&event->mmap_mutex);
3423 
3424         poll_wait(file, &event->waitq, wait);
3425 
3426         return events;
3427 }
3428 
3429 static void perf_event_reset(struct perf_event *event)
3430 {
3431         (void)perf_event_read(event);
3432         local64_set(&event->count, 0);
3433         perf_event_update_userpage(event);
3434 }
3435 
3436 /*
3437  * Holding the top-level event's child_mutex means that any
3438  * descendant process that has inherited this event will block
3439  * in sync_child_event if it goes to exit, thus satisfying the
3440  * task existence requirements of perf_event_enable/disable.
3441  */
3442 static void perf_event_for_each_child(struct perf_event *event,
3443                                         void (*func)(struct perf_event *))
3444 {
3445         struct perf_event *child;
3446 
3447         WARN_ON_ONCE(event->ctx->parent_ctx);
3448         mutex_lock(&event->child_mutex);
3449         func(event);
3450         list_for_each_entry(child, &event->child_list, child_list)
3451                 func(child);
3452         mutex_unlock(&event->child_mutex);
3453 }
3454 
3455 static void perf_event_for_each(struct perf_event *event,
3456                                   void (*func)(struct perf_event *))
3457 {
3458         struct perf_event_context *ctx = event->ctx;
3459         struct perf_event *sibling;
3460 
3461         WARN_ON_ONCE(ctx->parent_ctx);
3462         mutex_lock(&ctx->mutex);
3463         event = event->group_leader;
3464 
3465         perf_event_for_each_child(event, func);
3466         list_for_each_entry(sibling, &event->sibling_list, group_entry)
3467                 perf_event_for_each_child(sibling, func);
3468         mutex_unlock(&ctx->mutex);
3469 }
3470 
3471 static int perf_event_period(struct perf_event *event, u64 __user *arg)
3472 {
3473         struct perf_event_context *ctx = event->ctx;
3474         int ret = 0;
3475         u64 value;
3476 
3477         if (!is_sampling_event(event))
3478                 return -EINVAL;
3479 
3480         if (copy_from_user(&value, arg, sizeof(value)))
3481                 return -EFAULT;
3482 
3483         if (!value)
3484                 return -EINVAL;
3485 
3486         raw_spin_lock_irq(&ctx->lock);
3487         if (event->attr.freq) {
3488                 if (value > sysctl_perf_event_sample_rate) {
3489                         ret = -EINVAL;
3490                         goto unlock;
3491                 }
3492 
3493                 event->attr.sample_freq = value;
3494         } else {
3495                 event->attr.sample_period = value;
3496                 event->hw.sample_period = value;
3497         }
3498 unlock:
3499         raw_spin_unlock_irq(&ctx->lock);
3500 
3501         return ret;
3502 }
3503 
3504 static const struct file_operations perf_fops;
3505 
3506 static inline int perf_fget_light(int fd, struct fd *p)
3507 {
3508         struct fd f = fdget(fd);
3509         if (!f.file)
3510                 return -EBADF;
3511 
3512         if (f.file->f_op != &perf_fops) {
3513                 fdput(f);
3514                 return -EBADF;
3515         }
3516         *p = f;
3517         return 0;
3518 }
3519 
3520 static int perf_event_set_output(struct perf_event *event,
3521                                  struct perf_event *output_event);
3522 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3523 
3524 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3525 {
3526         struct perf_event *event = file->private_data;
3527         void (*func)(struct perf_event *);
3528         u32 flags = arg;
3529 
3530         switch (cmd) {
3531         case PERF_EVENT_IOC_ENABLE:
3532                 func = perf_event_enable;
3533                 break;
3534         case PERF_EVENT_IOC_DISABLE:
3535                 func = perf_event_disable;
3536                 break;
3537         case PERF_EVENT_IOC_RESET:
3538                 func = perf_event_reset;
3539                 break;
3540 
3541         case PERF_EVENT_IOC_REFRESH:
3542                 return perf_event_refresh(event, arg);
3543 
3544         case PERF_EVENT_IOC_PERIOD:
3545                 return perf_event_period(event, (u64 __user *)arg);
3546 
3547         case PERF_EVENT_IOC_SET_OUTPUT:
3548         {
3549                 int ret;
3550                 if (arg != -1) {
3551                         struct perf_event *output_event;
3552                         struct fd output;
3553                         ret = perf_fget_light(arg, &output);
3554                         if (ret)
3555                                 return ret;
3556                         output_event = output.file->private_data;
3557                         ret = perf_event_set_output(event, output_event);
3558                         fdput(output);
3559                 } else {
3560                         ret = perf_event_set_output(event, NULL);
3561                 }
3562                 return ret;
3563         }
3564 
3565         case PERF_EVENT_IOC_SET_FILTER:
3566                 return perf_event_set_filter(event, (void __user *)arg);
3567 
3568         default:
3569                 return -ENOTTY;
3570         }
3571 
3572         if (flags & PERF_IOC_FLAG_GROUP)
3573                 perf_event_for_each(event, func);
3574         else
3575                 perf_event_for_each_child(event, func);
3576 
3577         return 0;
3578 }
3579 
3580 int perf_event_task_enable(void)
3581 {
3582         struct perf_event *event;
3583 
3584         mutex_lock(&current->perf_event_mutex);
3585         list_for_each_entry(event, &current->perf_event_list, owner_entry)
3586                 perf_event_for_each_child(event, perf_event_enable);
3587         mutex_unlock(&current->perf_event_mutex);
3588 
3589         return 0;
3590 }
3591 
3592 int perf_event_task_disable(void)
3593 {
3594         struct perf_event *event;
3595 
3596         mutex_lock(&current->perf_event_mutex);
3597         list_for_each_entry(event, &current->perf_event_list, owner_entry)
3598                 perf_event_for_each_child(event, perf_event_disable);
3599         mutex_unlock(&current->perf_event_mutex);
3600 
3601         return 0;
3602 }
3603 
3604 static int perf_event_index(struct perf_event *event)
3605 {
3606         if (event->hw.state & PERF_HES_STOPPED)
3607                 return 0;
3608 
3609         if (event->state != PERF_EVENT_STATE_ACTIVE)
3610                 return 0;
3611 
3612         return event->pmu->event_idx(event);
3613 }
3614 
3615 static void calc_timer_values(struct perf_event *event,
3616                                 u64 *now,
3617                                 u64 *enabled,
3618                                 u64 *running)
3619 {
3620         u64 ctx_time;
3621 
3622         *now = perf_clock();
3623         ctx_time = event->shadow_ctx_time + *now;
3624         *enabled = ctx_time - event->tstamp_enabled;
3625         *running = ctx_time - event->tstamp_running;
3626 }
3627 
3628 void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
3629 {
3630 }
3631 
3632 /*
3633  * Callers need to ensure there can be no nesting of this function, otherwise
3634  * the seqlock logic goes bad. We can not serialize this because the arch
3635  * code calls this from NMI context.
3636  */
3637 void perf_event_update_userpage(struct perf_event *event)
3638 {
3639         struct perf_event_mmap_page *userpg;
3640         struct ring_buffer *rb;
3641         u64 enabled, running, now;
3642 
3643         rcu_read_lock();
3644         /*
3645          * compute total_time_enabled, total_time_running
3646          * based on snapshot values taken when the event
3647          * was last scheduled in.
3648          *
3649          * we cannot simply called update_context_time()
3650          * because of locking issue as we can be called in
3651          * NMI context
3652          */
3653         calc_timer_values(event, &now, &enabled, &running);
3654         rb = rcu_dereference(event->rb);
3655         if (!rb)
3656                 goto unlock;
3657 
3658         userpg = rb->user_page;
3659 
3660         /*
3661          * Disable preemption so as to not let the corresponding user-space
3662          * spin too long if we get preempted.
3663          */
3664         preempt_disable();
3665         ++userpg->lock;
3666         barrier();
3667         userpg->index = perf_event_index(event);
3668         userpg->offset = perf_event_count(event);
3669         if (userpg->index)
3670                 userpg->offset -= local64_read(&event->hw.prev_count);
3671 
3672         userpg->time_enabled = enabled +
3673                         atomic64_read(&event->child_total_time_enabled);
3674 
3675         userpg->time_running = running +
3676                         atomic64_read(&event->child_total_time_running);
3677 
3678         arch_perf_update_userpage(userpg, now);
3679 
3680         barrier();
3681         ++userpg->lock;
3682         preempt_enable();
3683 unlock:
3684         rcu_read_unlock();
3685 }
3686 
3687 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3688 {
3689         struct perf_event *event = vma->vm_file->private_data;
3690         struct ring_buffer *rb;
3691         int ret = VM_FAULT_SIGBUS;
3692 
3693         if (vmf->flags & FAULT_FLAG_MKWRITE) {
3694                 if (vmf->pgoff == 0)
3695                         ret = 0;
3696                 return ret;
3697         }
3698 
3699         rcu_read_lock();
3700         rb = rcu_dereference(event->rb);
3701         if (!rb)
3702                 goto unlock;
3703 
3704         if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3705                 goto unlock;
3706 
3707         vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
3708         if (!vmf->page)
3709                 goto unlock;
3710 
3711         get_page(vmf->page);
3712         vmf->page->mapping = vma->vm_file->f_mapping;
3713         vmf->page->index   = vmf->pgoff;
3714 
3715         ret = 0;
3716 unlock:
3717         rcu_read_unlock();
3718 
3719         return ret;
3720 }
3721 
3722 static void ring_buffer_attach(struct perf_event *event,
3723                                struct ring_buffer *rb)
3724 {
3725         unsigned long flags;
3726 
3727         if (!list_empty(&event->rb_entry))
3728                 return;
3729 
3730         spin_lock_irqsave(&rb->event_lock, flags);
3731         if (list_empty(&event->rb_entry))
3732                 list_add(&event->rb_entry, &rb->event_list);
3733         spin_unlock_irqrestore(&rb->event_lock, flags);
3734 }
3735 
3736 static void ring_buffer_detach(struct perf_event *event, struct ring_buffer *rb)
3737 {
3738         unsigned long flags;
3739 
3740         if (list_empty(&event->rb_entry))
3741                 return;
3742 
3743         spin_lock_irqsave(&rb->event_lock, flags);
3744         list_del_init(&event->rb_entry);
3745         wake_up_all(&event->waitq);
3746         spin_unlock_irqrestore(&rb->event_lock, flags);
3747 }
3748 
3749 static void ring_buffer_wakeup(struct perf_event *event)
3750 {
3751         struct ring_buffer *rb;
3752 
3753         rcu_read_lock();
3754         rb = rcu_dereference(event->rb);
3755         if (rb) {
3756                 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
3757                         wake_up_all(&event->waitq);
3758         }
3759         rcu_read_unlock();
3760 }
3761 
3762 static void rb_free_rcu(struct rcu_head *rcu_head)
3763 {
3764         struct ring_buffer *rb;
3765 
3766         rb = container_of(rcu_head, struct ring_buffer, rcu_head);
3767         rb_free(rb);
3768 }
3769 
3770 static struct ring_buffer *ring_buffer_get(struct perf_event *event)
3771 {
3772         struct ring_buffer *rb;
3773 
3774         rcu_read_lock();
3775         rb = rcu_dereference(event->rb);
3776         if (rb) {
3777                 if (!atomic_inc_not_zero(&rb->refcount))
3778                         rb = NULL;
3779         }
3780         rcu_read_unlock();
3781 
3782         return rb;
3783 }
3784 
3785 static void ring_buffer_put(struct ring_buffer *rb)
3786 {
3787         if (!atomic_dec_and_test(&rb->refcount))
3788                 return;
3789 
3790         WARN_ON_ONCE(!list_empty(&rb->event_list));
3791 
3792         call_rcu(&rb->rcu_head, rb_free_rcu);
3793 }
3794 
3795 static void perf_mmap_open(struct vm_area_struct *vma)
3796 {
3797         struct perf_event *event = vma->vm_file->private_data;
3798 
3799         atomic_inc(&event->mmap_count);
3800         atomic_inc(&event->rb->mmap_count);
3801 }
3802 
3803 /*
3804  * A buffer can be mmap()ed multiple times; either directly through the same
3805  * event, or through other events by use of perf_event_set_output().
3806  *
3807  * In order to undo the VM accounting done by perf_mmap() we need to destroy
3808  * the buffer here, where we still have a VM context. This means we need
3809  * to detach all events redirecting to us.
3810  */
3811 static void perf_mmap_close(struct vm_area_struct *vma)
3812 {
3813         struct perf_event *event = vma->vm_file->private_data;
3814 
3815         struct ring_buffer *rb = event->rb;
3816         struct user_struct *mmap_user = rb->mmap_user;
3817         int mmap_locked = rb->mmap_locked;
3818         unsigned long size = perf_data_size(rb);
3819 
3820         atomic_dec(&rb->mmap_count);
3821 
3822         if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
3823                 return;
3824 
3825         /* Detach current event from the buffer. */
3826         rcu_assign_pointer(event->rb, NULL);
3827         ring_buffer_detach(event, rb);
3828         mutex_unlock(&event->mmap_mutex);
3829 
3830         /* If there's still other mmap()s of this buffer, we're done. */
3831         if (atomic_read(&rb->mmap_count)) {
3832                 ring_buffer_put(rb); /* can't be last */
3833                 return;
3834         }
3835 
3836         /*
3837          * No other mmap()s, detach from all other events that might redirect
3838          * into the now unreachable buffer. Somewhat complicated by the
3839          * fact that rb::event_lock otherwise nests inside mmap_mutex.
3840          */
3841 again:
3842         rcu_read_lock();
3843         list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
3844                 if (!atomic_long_inc_not_zero(&event->refcount)) {
3845                         /*
3846                          * This event is en-route to free_event() which will
3847                          * detach it and remove it from the list.
3848                          */
3849                         continue;
3850                 }
3851                 rcu_read_unlock();
3852 
3853                 mutex_lock(&event->mmap_mutex);
3854                 /*
3855                  * Check we didn't race with perf_event_set_output() which can
3856                  * swizzle the rb from under us while we were waiting to
3857                  * acquire mmap_mutex.
3858                  *
3859                  * If we find a different rb; ignore this event, a next
3860                  * iteration will no longer find it on the list. We have to
3861                  * still restart the iteration to make sure we're not now
3862                  * iterating the wrong list.
3863                  */
3864                 if (event->rb == rb) {
3865                         rcu_assign_pointer(event->rb, NULL);
3866                         ring_buffer_detach(event, rb);
3867                         ring_buffer_put(rb); /* can't be last, we still have one */
3868                 }
3869                 mutex_unlock(&event->mmap_mutex);
3870                 put_event(event);
3871 
3872                 /*
3873                  * Restart the iteration; either we're on the wrong list or
3874                  * destroyed its integrity by doing a deletion.
3875                  */
3876                 goto again;
3877         }
3878         rcu_read_unlock();
3879 
3880         /*
3881          * It could be there's still a few 0-ref events on the list; they'll
3882          * get cleaned up by free_event() -- they'll also still have their
3883          * ref on the rb and will free it whenever they are done with it.
3884          *
3885          * Aside from that, this buffer is 'fully' detached and unmapped,
3886          * undo the VM accounting.
3887          */
3888 
3889         atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
3890         vma->vm_mm->pinned_vm -= mmap_locked;
3891         free_uid(mmap_user);
3892 
3893         ring_buffer_put(rb); /* could be last */
3894 }
3895 
3896 static const struct vm_operations_struct perf_mmap_vmops = {
3897         .open           = perf_mmap_open,
3898         .close          = perf_mmap_close,
3899         .fault          = perf_mmap_fault,
3900         .page_mkwrite   = perf_mmap_fault,
3901 };
3902 
3903 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3904 {
3905         struct perf_event *event = file->private_data;
3906         unsigned long user_locked, user_lock_limit;
3907         struct user_struct *user = current_user();
3908         unsigned long locked, lock_limit;
3909         struct ring_buffer *rb;
3910         unsigned long vma_size;
3911         unsigned long nr_pages;
3912         long user_extra, extra;
3913         int ret = 0, flags = 0;
3914 
3915         /*
3916          * Don't allow mmap() of inherited per-task counters. This would
3917          * create a performance issue due to all children writing to the
3918          * same rb.
3919          */
3920         if (event->cpu == -1 && event->attr.inherit)
3921                 return -EINVAL;
3922 
3923         if (!(vma->vm_flags & VM_SHARED))
3924                 return -EINVAL;
3925 
3926         vma_size = vma->vm_end - vma->vm_start;
3927         nr_pages = (vma_size / PAGE_SIZE) - 1;
3928 
3929         /*
3930          * If we have rb pages ensure they're a power-of-two number, so we
3931          * can do bitmasks instead of modulo.
3932          */
3933         if (nr_pages != 0 && !is_power_of_2(nr_pages))
3934                 return -EINVAL;
3935 
3936         if (vma_size != PAGE_SIZE * (1 + nr_pages))
3937                 return -EINVAL;
3938 
3939         if (vma->vm_pgoff != 0)
3940                 return -EINVAL;
3941 
3942         WARN_ON_ONCE(event->ctx->parent_ctx);
3943 again:
3944         mutex_lock(&event->mmap_mutex);
3945         if (event->rb) {
3946                 if (event->rb->nr_pages != nr_pages) {
3947                         ret = -EINVAL;
3948                         goto unlock;
3949                 }
3950 
3951                 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
3952                         /*
3953                          * Raced against perf_mmap_close() through
3954                          * perf_event_set_output(). Try again, hope for better
3955                          * luck.
3956                          */
3957                         mutex_unlock(&event->mmap_mutex);
3958                         goto again;
3959                 }
3960 
3961                 goto unlock;
3962         }
3963 
3964         user_extra = nr_pages + 1;
3965         user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3966 
3967         /*
3968          * Increase the limit linearly with more CPUs:
3969          */
3970         user_lock_limit *= num_online_cpus();
3971 
3972         user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3973 
3974         extra = 0;
3975         if (user_locked > user_lock_limit)
3976                 extra = user_locked - user_lock_limit;
3977 
3978         lock_limit = rlimit(RLIMIT_MEMLOCK);
3979         lock_limit >>= PAGE_SHIFT;
3980         locked = vma->vm_mm->pinned_vm + extra;
3981 
3982         if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3983                 !capable(CAP_IPC_LOCK)) {
3984                 ret = -EPERM;
3985                 goto unlock;
3986         }
3987 
3988         WARN_ON(event->rb);
3989 
3990         if (vma->vm_flags & VM_WRITE)
3991                 flags |= RING_BUFFER_WRITABLE;
3992 
3993         rb = rb_alloc(nr_pages, 
3994                 event->attr.watermark ? event->attr.wakeup_watermark : 0,
3995                 event->cpu, flags);
3996 
3997         if (!rb) {
3998                 ret = -ENOMEM;
3999                 goto unlock;
4000         }
4001 
4002         atomic_set(&rb->mmap_count, 1);
4003         rb->mmap_locked = extra;
4004         rb->mmap_user = get_current_user();
4005 
4006         atomic_long_add(user_extra, &user->locked_vm);
4007         vma->vm_mm->pinned_vm += extra;
4008 
4009         ring_buffer_attach(event, rb);
4010         rcu_assign_pointer(event->rb, rb);
4011 
4012         perf_event_update_userpage(event);
4013 
4014 unlock:
4015         if (!ret)
4016                 atomic_inc(&event->mmap_count);
4017         mutex_unlock(&event->mmap_mutex);
4018 
4019         /*
4020          * Since pinned accounting is per vm we cannot allow fork() to copy our
4021          * vma.
4022          */
4023         vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
4024         vma->vm_ops = &perf_mmap_vmops;
4025 
4026         return ret;
4027 }
4028 
4029 static int perf_fasync(int fd, struct file *filp, int on)
4030 {
4031         struct inode *inode = file_inode(filp);
4032         struct perf_event *event = filp->private_data;
4033         int retval;
4034 
4035         mutex_lock(&inode->i_mutex);
4036         retval = fasync_helper(fd, filp, on, &event->fasync);
4037         mutex_unlock(&inode->i_mutex);
4038 
4039         if (retval < 0)
4040                 return retval;
4041 
4042         return 0;
4043 }
4044 
4045 static const struct file_operations perf_fops = {
4046         .llseek                 = no_llseek,
4047         .release                = perf_release,
4048         .read                   = perf_read,
4049         .poll                   = perf_poll,
4050         .unlocked_ioctl         = perf_ioctl,
4051         .compat_ioctl           = perf_ioctl,
4052         .mmap                   = perf_mmap,
4053         .fasync                 = perf_fasync,
4054 };
4055 
4056 /*
4057  * Perf event wakeup
4058  *
4059  * If there's data, ensure we set the poll() state and publish everything
4060  * to user-space before waking everybody up.
4061  */
4062 
4063 void perf_event_wakeup(struct perf_event *event)
4064 {
4065         ring_buffer_wakeup(event);
4066 
4067         if (event->pending_kill) {
4068                 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
4069                 event->pending_kill = 0;
4070         }
4071 }
4072 
4073 static void perf_pending_event(struct irq_work *entry)
4074 {
4075         struct perf_event *event = container_of(entry,
4076                         struct perf_event, pending);
4077 
4078         if (event->pending_disable) {
4079                 event->pending_disable = 0;
4080                 __perf_event_disable(event);
4081         }
4082 
4083         if (event->pending_wakeup) {
4084                 event->pending_wakeup = 0;
4085                 perf_event_wakeup(event);
4086         }
4087 }
4088 
4089 /*
4090  * We assume there is only KVM supporting the callbacks.
4091  * Later on, we might change it to a list if there is
4092  * another virtualization implementation supporting the callbacks.
4093  */
4094 struct perf_guest_info_callbacks *perf_guest_cbs;
4095 
4096 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4097 {
4098         perf_guest_cbs = cbs;
4099         return 0;
4100 }
4101 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
4102 
4103 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
4104 {
4105         perf_guest_cbs = NULL;
4106         return 0;
4107 }
4108 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
4109 
4110 static void
4111 perf_output_sample_regs(struct perf_output_handle *handle,
4112                         struct pt_regs *regs, u64 mask)
4113 {
4114         int bit;
4115 
4116         for_each_set_bit(bit, (const unsigned long *) &mask,
4117                          sizeof(mask) * BITS_PER_BYTE) {
4118                 u64 val;
4119 
4120                 val = perf_reg_value(regs, bit);
4121                 perf_output_put(handle, val);
4122         }
4123 }
4124 
4125 static void perf_sample_regs_user(struct perf_regs_user *regs_user,
4126                                   struct pt_regs *regs)
4127 {
4128         if (!user_mode(regs)) {
4129                 if (current->mm)
4130                         regs = task_pt_regs(current);
4131                 else
4132                         regs = NULL;
4133         }
4134 
4135         if (regs) {
4136                 regs_user->regs = regs;
4137                 regs_user->abi  = perf_reg_abi(current);
4138         }
4139 }
4140 
4141 /*
4142  * Get remaining task size from user stack pointer.
4143  *
4144  * It'd be better to take stack vma map and limit this more
4145  * precisly, but there's no way to get it safely under interrupt,
4146  * so using TASK_SIZE as limit.
4147  */
4148 static u64 perf_ustack_task_size(struct pt_regs *regs)
4149 {
4150         unsigned long addr = perf_user_stack_pointer(regs);
4151 
4152         if (!addr || addr >= TASK_SIZE)
4153                 return 0;
4154 
4155         return TASK_SIZE - addr;
4156 }
4157 
4158 static u16
4159 perf_sample_ustack_size(u16 stack_size, u16 header_size,
4160                         struct pt_regs *regs)
4161 {
4162         u64 task_size;
4163 
4164         /* No regs, no stack pointer, no dump. */
4165         if (!regs)
4166                 return 0;
4167 
4168         /*
4169          * Check if we fit in with the requested stack size into the:
4170          * - TASK_SIZE
4171          *   If we don't, we limit the size to the TASK_SIZE.
4172          *
4173          * - remaining sample size
4174          *   If we don't, we customize the stack size to
4175          *   fit in to the remaining sample size.
4176          */
4177 
4178         task_size  = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
4179         stack_size = min(stack_size, (u16) task_size);
4180 
4181         /* Current header size plus static size and dynamic size. */
4182         header_size += 2 * sizeof(u64);
4183 
4184         /* Do we fit in with the current stack dump size? */
4185         if ((u16) (header_size + stack_size) < header_size) {
4186                 /*
4187                  * If we overflow the maximum size for the sample,
4188                  * we customize the stack dump size to fit in.
4189                  */
4190                 stack_size = USHRT_MAX - header_size - sizeof(u64);
4191                 stack_size = round_up(stack_size, sizeof(u64));
4192         }
4193 
4194         return stack_size;
4195 }
4196 
4197 static void
4198 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
4199                           struct pt_regs *regs)
4200 {
4201         /* Case of a kernel thread, nothing to dump */
4202         if (!regs) {
4203                 u64 size = 0;
4204                 perf_output_put(handle, size);
4205         } else {
4206                 unsigned long sp;
4207                 unsigned int rem;
4208                 u64 dyn_size;
4209 
4210                 /*
4211                  * We dump:
4212                  * static size
4213                  *   - the size requested by user or the best one we can fit
4214                  *     in to the sample max size
4215                  * data
4216                  *   - user stack dump data
4217                  * dynamic size
4218                  *   - the actual dumped size
4219                  */
4220 
4221                 /* Static size. */
4222                 perf_output_put(handle, dump_size);
4223 
4224                 /* Data. */
4225                 sp = perf_user_stack_pointer(regs);
4226                 rem = __output_copy_user(handle, (void *) sp, dump_size);
4227                 dyn_size = dump_size - rem;
4228 
4229                 perf_output_skip(handle, rem);
4230 
4231                 /* Dynamic size. */
4232                 perf_output_put(handle, dyn_size);
4233         }
4234 }
4235 
4236 static void __perf_event_header__init_id(struct perf_event_header *header,
4237                                          struct perf_sample_data *data,
4238                                          struct perf_event *event)
4239 {
4240         u64 sample_type = event->attr.sample_type;
4241 
4242         data->type = sample_type;
4243         header->size += event->id_header_size;
4244 
4245         if (sample_type & PERF_SAMPLE_TID) {
4246                 /* namespace issues */
4247                 data->tid_entry.pid = perf_event_pid(event, current);
4248                 data->tid_entry.tid = perf_event_tid(event, current);
4249         }
4250 
4251         if (sample_type & PERF_SAMPLE_TIME)
4252                 data->time = perf_clock();
4253 
4254         if (sample_type & PERF_SAMPLE_ID)
4255                 data->id = primary_event_id(event);
4256 
4257         if (sample_type & PERF_SAMPLE_STREAM_ID)
4258                 data->stream_id = event->id;
4259 
4260         if (sample_type & PERF_SAMPLE_CPU) {
4261                 data->cpu_entry.cpu      = raw_smp_processor_id();
4262                 data->cpu_entry.reserved = 0;
4263         }
4264 }
4265 
4266 void perf_event_header__init_id(struct perf_event_header *header,
4267                                 struct perf_sample_data *data,
4268                                 struct perf_event *event)
4269 {
4270         if (event->attr.sample_id_all)
4271                 __perf_event_header__init_id(header, data, event);
4272 }
4273 
4274 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
4275                                            struct perf_sample_data *data)
4276 {
4277         u64 sample_type = data->type;
4278 
4279         if (sample_type & PERF_SAMPLE_TID)
4280                 perf_output_put(handle, data->tid_entry);
4281 
4282         if (sample_type & PERF_SAMPLE_TIME)
4283                 perf_output_put(handle, data->time);
4284 
4285         if (sample_type & PERF_SAMPLE_ID)
4286                 perf_output_put(handle, data->id);
4287 
4288         if (sample_type & PERF_SAMPLE_STREAM_ID)
4289                 perf_output_put(handle, data->stream_id);
4290 
4291         if (sample_type & PERF_SAMPLE_CPU)
4292                 perf_output_put(handle, data->cpu_entry);
4293 }
4294 
4295 void perf_event__output_id_sample(struct perf_event *event,
4296                                   struct perf_output_handle *handle,
4297                                   struct perf_sample_data *sample)
4298 {
4299         if (event->attr.sample_id_all)
4300                 __perf_event__output_id_sample(handle, sample);
4301 }
4302 
4303 static void perf_output_read_one(struct perf_output_handle *handle,
4304                                  struct perf_event *event,
4305                                  u64 enabled, u64 running)
4306 {
4307         u64 read_format = event->attr.read_format;
4308         u64 values[4];
4309         int n = 0;
4310 
4311         values[n++] = perf_event_count(event);
4312         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4313                 values[n++] = enabled +
4314                         atomic64_read(&event->child_total_time_enabled);
4315         }
4316         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4317                 values[n++] = running +
4318                         atomic64_read(&event->child_total_time_running);
4319         }
4320         if (read_format & PERF_FORMAT_ID)
4321                 values[n++] = primary_event_id(event);
4322 
4323         __output_copy(handle, values, n * sizeof(u64));
4324 }
4325 
4326 /*
4327  * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
4328  */
4329 static void perf_output_read_group(struct perf_output_handle *handle,
4330                             struct perf_event *event,
4331                             u64 enabled, u64 running)
4332 {
4333         struct perf_event *leader = event->group_leader, *sub;
4334         u64 read_format = event->attr.read_format;
4335         u64 values[5];
4336         int n = 0;
4337 
4338         values[n++] = 1 + leader->nr_siblings;
4339 
4340         if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4341                 values[n++] = enabled;
4342 
4343         if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4344                 values[n++] = running;
4345 
4346         if (leader != event)
4347                 leader->pmu->read(leader);
4348 
4349         values[n++] = perf_event_count(leader);
4350         if (read_format & PERF_FORMAT_ID)
4351                 values[n++] = primary_event_id(leader);
4352 
4353         __output_copy(handle, values, n * sizeof(u64));
4354 
4355         list_for_each_entry(sub, &leader->sibling_list, group_entry) {
4356                 n = 0;
4357 
4358                 if (sub != event)
4359                         sub->pmu->read(sub);
4360 
4361                 values[n++] = perf_event_count(sub);
4362                 if (read_format & PERF_FORMAT_ID)
4363                         values[n++] = primary_event_id(sub);
4364 
4365                 __output_copy(handle, values, n * sizeof(u64));
4366         }
4367 }
4368 
4369 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
4370                                  PERF_FORMAT_TOTAL_TIME_RUNNING)
4371 
4372 static void perf_output_read(struct perf_output_handle *handle,
4373                              struct perf_event *event)
4374 {
4375         u64 enabled = 0, running = 0, now;
4376         u64 read_format = event->attr.read_format;
4377 
4378         /*
4379          * compute total_time_enabled, total_time_running
4380          * based on snapshot values taken when the event
4381          * was last scheduled in.
4382          *
4383          * we cannot simply called update_context_time()
4384          * because of locking issue as we are called in
4385          * NMI context
4386          */
4387         if (read_format & PERF_FORMAT_TOTAL_TIMES)
4388                 calc_timer_values(event, &now, &enabled, &running);
4389 
4390         if (event->attr.read_format & PERF_FORMAT_GROUP)
4391                 perf_output_read_group(handle, event, enabled, running);
4392         else
4393                 perf_output_read_one(handle, event, enabled, running);
4394 }
4395 
4396 void perf_output_sample(struct perf_output_handle *handle,
4397                         struct perf_event_header *header,
4398                         struct perf_sample_data *data,
4399                         struct perf_event *event)
4400 {
4401         u64 sample_type = data->type;
4402 
4403         perf_output_put(handle, *header);
4404 
4405         if (sample_type & PERF_SAMPLE_IP)
4406                 perf_output_put(handle, data->ip);
4407 
4408         if (sample_type & PERF_SAMPLE_TID)
4409                 perf_output_put(handle, data->tid_entry);
4410 
4411         if (sample_type & PERF_SAMPLE_TIME)
4412                 perf_output_put(handle, data->time);
4413 
4414         if (sample_type & PERF_SAMPLE_ADDR)
4415                 perf_output_put(handle, data->addr);
4416 
4417         if (sample_type & PERF_SAMPLE_ID)
4418                 perf_output_put(handle, data->id);
4419 
4420         if (sample_type & PERF_SAMPLE_STREAM_ID)
4421                 perf_output_put(handle, data->stream_id);
4422 
4423         if (sample_type & PERF_SAMPLE_CPU)
4424                 perf_output_put(handle, data->cpu_entry);
4425 
4426         if (sample_type & PERF_SAMPLE_PERIOD)
4427                 perf_output_put(handle, data->period);
4428 
4429         if (sample_type & PERF_SAMPLE_READ)
4430                 perf_output_read(handle, event);
4431 
4432         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4433                 if (data->callchain) {
4434                         int size = 1;
4435 
4436                         if (data->callchain)
4437                                 size += data->callchain->nr;
4438 
4439                         size *= sizeof(u64);
4440 
4441                         __output_copy(handle, data->callchain, size);
4442                 } else {
4443                         u64 nr = 0;
4444                         perf_output_put(handle, nr);
4445                 }
4446         }
4447 
4448         if (sample_type & PERF_SAMPLE_RAW) {
4449                 if (data->raw) {
4450                         perf_output_put(handle, data->raw->size);
4451                         __output_copy(handle, data->raw->data,
4452                                            data->raw->size);
4453                 } else {
4454                         struct {
4455                                 u32     size;
4456                                 u32     data;
4457                         } raw = {
4458                                 .size = sizeof(u32),
4459                                 .data = 0,
4460                         };
4461                         perf_output_put(handle, raw);
4462                 }
4463         }
4464 
4465         if (!event->attr.watermark) {
4466                 int wakeup_events = event->attr.wakeup_events;
4467 
4468                 if (wakeup_events) {
4469                         struct ring_buffer *rb = handle->rb;
4470                         int events = local_inc_return(&rb->events);
4471 
4472                         if (events >= wakeup_events) {
4473                                 local_sub(wakeup_events, &rb->events);
4474                                 local_inc(&rb->wakeup);
4475                         }
4476                 }
4477         }
4478 
4479         if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
4480                 if (data->br_stack) {
4481                         size_t size;
4482 
4483                         size = data->br_stack->nr
4484                              * sizeof(struct perf_branch_entry);
4485 
4486                         perf_output_put(handle, data->br_stack->nr);
4487                         perf_output_copy(handle, data->br_stack->entries, size);
4488                 } else {
4489                         /*
4490                          * we always store at least the value of nr
4491                          */
4492                         u64 nr = 0;
4493                         perf_output_put(handle, nr);
4494                 }
4495         }
4496 
4497         if (sample_type & PERF_SAMPLE_REGS_USER) {
4498                 u64 abi = data->regs_user.abi;
4499 
4500                 /*
4501                  * If there are no regs to dump, notice it through
4502                  * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
4503                  */
4504                 perf_output_put(handle, abi);
4505 
4506                 if (abi) {
4507                         u64 mask = event->attr.sample_regs_user;
4508                         perf_output_sample_regs(handle,
4509                                                 data->regs_user.regs,
4510                                                 mask);
4511                 }
4512         }
4513 
4514         if (sample_type & PERF_SAMPLE_STACK_USER)
4515                 perf_output_sample_ustack(handle,
4516                                           data->stack_user_size,
4517                                           data->regs_user.regs);
4518 
4519         if (sample_type & PERF_SAMPLE_WEIGHT)
4520                 perf_output_put(handle, data->weight);
4521 
4522         if (sample_type & PERF_SAMPLE_DATA_SRC)
4523                 perf_output_put(handle, data->data_src.val);
4524 }
4525 
4526 void perf_prepare_sample(struct perf_event_header *header,
4527                          struct perf_sample_data *data,
4528                          struct perf_event *event,
4529                          struct pt_regs *regs)
4530 {
4531         u64 sample_type = event->attr.sample_type;
4532 
4533         header->type = PERF_RECORD_SAMPLE;
4534         header->size = sizeof(*header) + event->header_size;
4535 
4536         header->misc = 0;
4537         header->misc |= perf_misc_flags(regs);
4538 
4539         __perf_event_header__init_id(header, data, event);
4540 
4541         if (sample_type & PERF_SAMPLE_IP)
4542                 data->ip = perf_instruction_pointer(regs);
4543 
4544         if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4545                 int size = 1;
4546 
4547                 data->callchain = perf_callchain(event, regs);
4548 
4549                 if (data->callchain)
4550                         size += data->callchain->nr;
4551 
4552                 header->size += size * sizeof(u64);
4553         }
4554 
4555         if (sample_type & PERF_SAMPLE_RAW) {
4556                 int size = sizeof(u32);
4557 
4558                 if (data->raw)
4559                         size += data->raw->size;
4560                 else
4561                         size += sizeof(u32);
4562 
4563                 WARN_ON_ONCE(size & (sizeof(u64)-1));
4564                 header->size += size;
4565         }
4566 
4567         if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
4568                 int size = sizeof(u64); /* nr */
4569                 if (data->br_stack) {
4570                         size += data->br_stack->nr
4571                               * sizeof(struct perf_branch_entry);
4572                 }
4573                 header->size += size;
4574         }
4575 
4576         if (sample_type & PERF_SAMPLE_REGS_USER) {
4577                 /* regs dump ABI info */
4578                 int size = sizeof(u64);
4579 
4580                 perf_sample_regs_user(&data->regs_user, regs);
4581 
4582                 if (data->regs_user.regs) {
4583                         u64 mask = event->attr.sample_regs_user;
4584                         size += hweight64(mask) * sizeof(u64);
4585                 }
4586 
4587                 header->size += size;
4588         }
4589 
4590         if (sample_type & PERF_SAMPLE_STACK_USER) {
4591                 /*
4592                  * Either we need PERF_SAMPLE_STACK_USER bit to be allways
4593                  * processed as the last one or have additional check added
4594                  * in case new sample type is added, because we could eat
4595                  * up the rest of the sample size.
4596                  */
4597                 struct perf_regs_user *uregs = &data->regs_user;
4598                 u16 stack_size = event->attr.sample_stack_user;
4599                 u16 size = sizeof(u64);
4600 
4601                 if (!uregs->abi)
4602                         perf_sample_regs_user(uregs, regs);
4603 
4604                 stack_size = perf_sample_ustack_size(stack_size, header->size,
4605                                                      uregs->regs);
4606 
4607                 /*
4608                  * If there is something to dump, add space for the dump
4609                  * itself and for the field that tells the dynamic size,
4610                  * which is how many have been actually dumped.
4611                  */
4612                 if (stack_size)
4613                         size += sizeof(u64) + stack_size;
4614 
4615                 data->stack_user_size = stack_size;
4616                 header->size += size;
4617         }
4618 }
4619 
4620 static void perf_event_output(struct perf_event *event,
4621                                 struct perf_sample_data *data,
4622                                 struct pt_regs *regs)
4623 {
4624         struct perf_output_handle handle;
4625         struct perf_event_header header;
4626 
4627         /* protect the callchain buffers */
4628         rcu_read_lock();
4629 
4630         perf_prepare_sample(&header, data, event, regs);
4631 
4632         if (perf_output_begin(&handle, event, header.size))
4633                 goto exit;
4634 
4635         perf_output_sample(&handle, &header, data, event);
4636 
4637         perf_output_end(&handle);
4638 
4639 exit:
4640         rcu_read_unlock();
4641 }
4642 
4643 /*
4644  * read event_id
4645  */
4646 
4647 struct perf_read_event {
4648         struct perf_event_header        header;
4649 
4650         u32                             pid;
4651         u32                             tid;
4652 };
4653 
4654 static void
4655 perf_event_read_event(struct perf_event *event,
4656                         struct task_struct *task)
4657 {
4658         struct perf_output_handle handle;
4659         struct perf_sample_data sample;
4660         struct perf_read_event read_event = {
4661                 .header = {
4662                         .type = PERF_RECORD_READ,
4663                         .misc = 0,
4664                         .size = sizeof(read_event) + event->read_size,
4665                 },
4666                 .pid = perf_event_pid(event, task),
4667                 .tid = perf_event_tid(event, task),
4668         };
4669         int ret;
4670 
4671         perf_event_header__init_id(&read_event.header, &sample, event);
4672         ret = perf_output_begin(&handle, event, read_event.header.size);
4673         if (ret)
4674                 return;
4675 
4676         perf_output_put(&handle, read_event);
4677         perf_output_read(&handle, event);
4678         perf_event__output_id_sample(event, &handle, &sample);
4679 
4680         perf_output_end(&handle);
4681 }
4682 
4683 typedef int  (perf_event_aux_match_cb)(struct perf_event *event, void *data);
4684 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data);
4685 
4686 static void
4687 perf_event_aux_ctx(struct perf_event_context *ctx,
4688                    perf_event_aux_match_cb match,
4689                    perf_event_aux_output_cb output,
4690                    void *data)
4691 {
4692         struct perf_event *event;
4693 
4694         list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4695                 if (event->state < PERF_EVENT_STATE_INACTIVE)
4696                         continue;
4697                 if (!event_filter_match(event))
4698                         continue;
4699                 if (match(event, data))
4700                         output(event, data);
4701         }
4702 }
4703 
4704 static void
4705 perf_event_aux(perf_event_aux_match_cb match,
4706                perf_event_aux_output_cb output,
4707                void *data,
4708                struct perf_event_context *task_ctx)
4709 {
4710         struct perf_cpu_context *cpuctx;
4711         struct perf_event_context *ctx;
4712         struct pmu *pmu;
4713         int ctxn;
4714 
4715         rcu_read_lock();
4716         list_for_each_entry_rcu(pmu, &pmus, entry) {
4717                 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4718                 if (cpuctx->unique_pmu != pmu)
4719                         goto next;
4720                 perf_event_aux_ctx(&cpuctx->ctx, match, output, data);
4721                 if (task_ctx)
4722                         goto next;
4723                 ctxn = pmu->task_ctx_nr;
4724                 if (ctxn < 0)
4725                         goto next;
4726                 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4727                 if (ctx)
4728                         perf_event_aux_ctx(ctx, match, output, data);
4729 next:
4730                 put_cpu_ptr(pmu->pmu_cpu_context);
4731         }
4732 
4733         if (task_ctx) {
4734                 preempt_disable();
4735                 perf_event_aux_ctx(task_ctx, match, output, data);
4736                 preempt_enable();
4737         }
4738         rcu_read_unlock();
4739 }
4740 
4741 /*
4742  * task tracking -- fork/exit
4743  *
4744  * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4745  */
4746 
4747 struct perf_task_event {
4748         struct task_struct              *task;
4749         struct perf_event_context       *task_ctx;
4750 
4751         struct {
4752                 struct perf_event_header        header;
4753 
4754                 u32                             pid;
4755                 u32                             ppid;
4756                 u32                             tid;
4757                 u32                             ptid;
4758                 u64                             time;
4759         } event_id;
4760 };
4761 
4762 static void perf_event_task_output(struct perf_event *event,
4763                                    void *data)
4764 {
4765         struct perf_task_event *task_event = data;
4766         struct perf_output_handle handle;
4767         struct perf_sample_data sample;
4768         struct task_struct *task = task_event->task;
4769         int ret, size = task_event->event_id.header.size;
4770 
4771         perf_event_header__init_id(&task_event->event_id.header, &sample, event);
4772 
4773         ret = perf_output_begin(&handle, event,
4774                                 task_event->event_id.header.size);
4775         if (ret)
4776                 goto out;
4777 
4778         task_event->event_id.pid = perf_event_pid(event, task);
4779         task_event->event_id.ppid = perf_event_pid(event, current);
4780 
4781         task_event->event_id.tid = perf_event_tid(event, task);
4782         task_event->event_id.ptid = perf_event_tid(event, current);
4783 
4784         perf_output_put(&handle, task_event->event_id);
4785 
4786         perf_event__output_id_sample(event, &handle, &sample);
4787 
4788         perf_output_end(&handle);
4789 out:
4790         task_event->event_id.header.size = size;
4791 }
4792 
4793 static int perf_event_task_match(struct perf_event *event,
4794                                  void *data __maybe_unused)
4795 {
4796         return event->attr.comm || event->attr.mmap ||
4797                event->attr.mmap_data || event->attr.task;
4798 }
4799 
4800 static void perf_event_task(struct task_struct *task,
4801                               struct perf_event_context *task_ctx,
4802                               int new)
4803 {
4804         struct perf_task_event task_event;
4805 
4806         if (!atomic_read(&nr_comm_events) &&
4807             !atomic_read(&nr_mmap_events) &&
4808             !atomic_read(&nr_task_events))
4809                 return;
4810 
4811         task_event = (struct perf_task_event){
4812                 .task     = task,
4813                 .task_ctx = task_ctx,
4814                 .event_id    = {
4815                         .header = {
4816                                 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4817                                 .misc = 0,
4818                                 .size = sizeof(task_event.event_id),
4819                         },
4820                         /* .pid  */
4821                         /* .ppid */
4822                         /* .tid  */
4823                         /* .ptid */
4824                         .time = perf_clock(),
4825                 },
4826         };
4827 
4828         perf_event_aux(perf_event_task_match,
4829                        perf_event_task_output,
4830                        &task_event,
4831                        task_ctx);
4832 }
4833 
4834 void perf_event_fork(struct task_struct *task)
4835 {
4836         perf_event_task(task, NULL, 1);
4837 }
4838 
4839 /*
4840  * comm tracking
4841  */
4842 
4843 struct perf_comm_event {
4844         struct task_struct      *task;
4845         char                    *comm;
4846         int                     comm_size;
4847 
4848         struct {
4849                 struct perf_event_header        header;
4850 
4851                 u32                             pid;
4852                 u32                             tid;
4853         } event_id;
4854 };
4855 
4856 static void perf_event_comm_output(struct perf_event *event,
4857                                    void *data)
4858 {
4859         struct perf_comm_event *comm_event = data;
4860         struct perf_output_handle handle;
4861         struct perf_sample_data sample;
4862         int size = comm_event->event_id.header.size;
4863         int ret;
4864 
4865         perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4866         ret = perf_output_begin(&handle, event,
4867                                 comm_event->event_id.header.size);
4868 
4869         if (ret)
4870                 goto out;
4871 
4872         comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4873         comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4874 
4875         perf_output_put(&handle, comm_event->event_id);
4876         __output_copy(&handle, comm_event->comm,
4877                                    comm_event->comm_size);
4878 
4879         perf_event__output_id_sample(event, &handle, &sample);
4880 
4881         perf_output_end(&handle);
4882 out:
4883         comm_event->event_id.header.size = size;
4884 }
4885 
4886 static int perf_event_comm_match(struct perf_event *event,
4887                                  void *data __maybe_unused)
4888 {
4889         return event->attr.comm;
4890 }
4891 
4892 static void perf_event_comm_event(struct perf_comm_event *comm_event)
4893 {
4894         char comm[TASK_COMM_LEN];
4895         unsigned int size;
4896 
4897         memset(comm, 0, sizeof(comm));
4898         strlcpy(comm, comm_event->task->comm, sizeof(comm));
4899         size = ALIGN(strlen(comm)+1, sizeof(u64));
4900 
4901         comm_event->comm = comm;
4902         comm_event->comm_size = size;
4903 
4904         comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4905 
4906         perf_event_aux(perf_event_comm_match,
4907                        perf_event_comm_output,
4908                        comm_event,
4909                        NULL);
4910 }
4911 
4912 void perf_event_comm(struct task_struct *task)
4913 {
4914         struct perf_comm_event comm_event;
4915         struct perf_event_context *ctx;
4916         int ctxn;
4917 
4918         rcu_read_lock();
4919         for_each_task_context_nr(ctxn) {
4920                 ctx = task->perf_event_ctxp[ctxn];
4921                 if (!ctx)
4922                         continue;
4923 
4924                 perf_event_enable_on_exec(ctx);
4925         }
4926         rcu_read_unlock();
4927 
4928         if (!atomic_read(&nr_comm_events))
4929                 return;
4930 
4931         comm_event = (struct perf_comm_event){
4932                 .task   = task,
4933                 /* .comm      */
4934                 /* .comm_size */
4935                 .event_id  = {
4936                         .header = {
4937                                 .type = PERF_RECORD_COMM,
4938                                 .misc = 0,
4939                                 /* .size */
4940                         },
4941                         /* .pid */
4942                         /* .tid */
4943                 },
4944         };
4945 
4946         perf_event_comm_event(&comm_event);
4947 }
4948 
4949 /*
4950  * mmap tracking
4951  */
4952 
4953 struct perf_mmap_event {
4954         struct vm_area_struct   *vma;
4955 
4956         const char              *file_name;
4957         int                     file_size;
4958 
4959         struct {
4960                 struct perf_event_header        header;
4961 
4962                 u32                             pid;
4963                 u32                             tid;
4964                 u64                             start;
4965                 u64                             len;
4966                 u64                             pgoff;
4967         } event_id;
4968 };
4969 
4970 static void perf_event_mmap_output(struct perf_event *event,
4971                                    void *data)
4972 {
4973         struct perf_mmap_event *mmap_event = data;
4974         struct perf_output_handle handle;
4975         struct perf_sample_data sample;
4976         int size = mmap_event->event_id.header.size;
4977         int ret;
4978 
4979         perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4980         ret = perf_output_begin(&handle, event,
4981                                 mmap_event->event_id.header.size);
4982         if (ret)
4983                 goto out;
4984 
4985         mmap_event->event_id.pid = perf_event_pid(event, current);
4986         mmap_event->event_id.tid = perf_event_tid(event, current);
4987 
4988         perf_output_put(&handle, mmap_event->event_id);
4989         __output_copy(&handle, mmap_event->file_name,
4990                                    mmap_event->file_size);
4991 
4992         perf_event__output_id_sample(event, &handle, &sample);
4993 
4994         perf_output_end(&handle);
4995 out:
4996         mmap_event->event_id.header.size = size;
4997 }
4998 
4999 static int perf_event_mmap_match(struct perf_event *event,
5000                                  void *data)
5001 {
5002         struct perf_mmap_event *mmap_event = data;
5003         struct vm_area_struct *vma = mmap_event->vma;
5004         int executable = vma->vm_flags & VM_EXEC;
5005 
5006         return (!executable && event->attr.mmap_data) ||
5007                (executable && event->attr.mmap);
5008 }
5009 
5010 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
5011 {
5012         struct vm_area_struct *vma = mmap_event->vma;
5013         struct file *file = vma->vm_file;
5014         unsigned int size;
5015         char tmp[16];
5016         char *buf = NULL;
5017         const char *name;
5018 
5019         memset(tmp, 0, sizeof(tmp));
5020 
5021         if (file) {
5022                 /*
5023                  * d_path works from the end of the rb backwards, so we
5024                  * need to add enough zero bytes after the string to handle
5025                  * the 64bit alignment we do later.
5026                  */
5027                 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
5028                 if (!buf) {
5029                         name = strncpy(tmp, "//enomem", sizeof(tmp));
5030                         goto got_name;
5031                 }
5032                 name = d_path(&file->f_path, buf, PATH_MAX);
5033                 if (IS_ERR(name)) {
5034                         name = strncpy(tmp, "//toolong", sizeof(tmp));
5035                         goto got_name;
5036                 }
5037         } else {
5038                 if (arch_vma_name(mmap_event->vma)) {
5039                         name = strncpy(tmp, arch_vma_name(mmap_event->vma),
5040                                        sizeof(tmp) - 1);
5041                         tmp[sizeof(tmp) - 1] = '\0';
5042                         goto got_name;
5043                 }
5044 
5045                 if (!vma->vm_mm) {
5046                         name = strncpy(tmp, "[vdso]", sizeof(tmp));
5047                         goto got_name;
5048                 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
5049                                 vma->vm_end >= vma->vm_mm->brk) {
5050                         name = strncpy(tmp, "[heap]", sizeof(tmp));
5051                         goto got_name;
5052                 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
5053                                 vma->vm_end >= vma->vm_mm->start_stack) {
5054                         name = strncpy(tmp, "[stack]", sizeof(tmp));
5055                         goto got_name;
5056                 }
5057 
5058                 name = strncpy(tmp, "//anon", sizeof(tmp));
5059                 goto got_name;
5060         }
5061 
5062 got_name:
5063         size = ALIGN(strlen(name)+1, sizeof(u64));
5064 
5065         mmap_event->file_name = name;
5066         mmap_event->file_size = size;
5067 
5068         if (!(vma->vm_flags & VM_EXEC))
5069                 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
5070 
5071         mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
5072 
5073         perf_event_aux(perf_event_mmap_match,
5074                        perf_event_mmap_output,
5075                        mmap_event,
5076                        NULL);
5077 
5078         kfree(buf);
5079 }
5080 
5081 void perf_event_mmap(struct vm_area_struct *vma)
5082 {
5083         struct perf_mmap_event mmap_event;
5084 
5085         if (!atomic_read(&nr_mmap_events))
5086                 return;
5087 
5088         mmap_event = (struct perf_mmap_event){
5089                 .vma    = vma,
5090                 /* .file_name */
5091                 /* .file_size */
5092                 .event_id  = {
5093                         .header = {
5094                                 .type = PERF_RECORD_MMAP,
5095                                 .misc = PERF_RECORD_MISC_USER,
5096                                 /* .size */
5097                         },
5098                         /* .pid */
5099                         /* .tid */
5100                         .start  = vma->vm_start,
5101                         .len    = vma->vm_end - vma->vm_start,
5102                         .pgoff  = (u64)vma->vm_pgoff << PAGE_SHIFT,
5103                 },
5104         };
5105 
5106         perf_event_mmap_event(&mmap_event);
5107 }
5108 
5109 /*
5110  * IRQ throttle logging
5111  */
5112 
5113 static void perf_log_throttle(struct perf_event *event, int enable)
5114 {
5115         struct perf_output_handle handle;
5116         struct perf_sample_data sample;
5117         int ret;
5118 
5119         struct {
5120                 struct perf_event_header        header;
5121                 u64                             time;
5122                 u64                             id;
5123                 u64                             stream_id;
5124         } throttle_event = {
5125                 .header = {
5126                         .type = PERF_RECORD_THROTTLE,
5127                         .misc = 0,
5128                         .size = sizeof(throttle_event),
5129                 },
5130                 .time           = perf_clock(),
5131                 .id             = primary_event_id(event),
5132                 .stream_id      = event->id,
5133         };
5134 
5135         if (enable)
5136                 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
5137 
5138         perf_event_header__init_id(&throttle_event.header, &sample, event);
5139 
5140         ret = perf_output_begin(&handle, event,
5141                                 throttle_event.header.size);
5142         if (ret)
5143                 return;
5144 
5145         perf_output_put(&handle, throttle_event);
5146         perf_event__output_id_sample(event, &handle, &sample);
5147         perf_output_end(&handle);
5148 }
5149 
5150 /*
5151  * Generic event overflow handling, sampling.
5152  */
5153 
5154 static int __perf_event_overflow(struct perf_event *event,
5155                                    int throttle, struct perf_sample_data *data,
5156                                    struct pt_regs *regs)
5157 {
5158         int events = atomic_read(&event->event_limit);
5159         struct hw_perf_event *hwc = &event->hw;
5160         u64 seq;
5161         int ret = 0;
5162 
5163         /*
5164          * Non-sampling counters might still use the PMI to fold short
5165          * hardware counters, ignore those.
5166          */
5167         if (unlikely(!is_sampling_event(event)))
5168                 return 0;
5169 
5170         seq = __this_cpu_read(perf_throttled_seq);
5171         if (seq != hwc->interrupts_seq) {
5172                 hwc->interrupts_seq = seq;
5173                 hwc->interrupts = 1;
5174         } else {
5175                 hwc->interrupts++;
5176                 if (unlikely(throttle
5177                              && hwc->interrupts >= max_samples_per_tick)) {
5178                         __this_cpu_inc(perf_throttled_count);
5179                         hwc->interrupts = MAX_INTERRUPTS;
5180                         perf_log_throttle(event, 0);
5181                         ret = 1;
5182                 }
5183         }
5184 
5185         if (event->attr.freq) {
5186                 u64 now = perf_clock();
5187                 s64 delta = now - hwc->freq_time_stamp;
5188 
5189                 hwc->freq_time_stamp = now;
5190 
5191                 if (delta > 0 && delta < 2*TICK_NSEC)
5192                         perf_adjust_period(event, delta, hwc->last_period, true);
5193         }
5194 
5195         /*
5196          * XXX event_limit might not quite work as expected on inherited
5197          * events
5198          */
5199 
5200         event->pending_kill = POLL_IN;
5201         if (events && atomic_dec_and_test(&event->event_limit)) {
5202                 ret = 1;
5203                 event->pending_kill = POLL_HUP;
5204                 event->pending_disable = 1;
5205                 irq_work_queue(&event->pending);
5206         }
5207 
5208         if (event->overflow_handler)
5209                 event->overflow_handler(event, data, regs);
5210         else
5211                 perf_event_output(event, data, regs);
5212 
5213         if (event->fasync && event->pending_kill) {
5214                 event->pending_wakeup = 1;
5215                 irq_work_queue(&event->pending);
5216         }
5217 
5218         return ret;
5219 }
5220 
5221 int perf_event_overflow(struct perf_event *event,
5222                           struct perf_sample_data *data,
5223                           struct pt_regs *regs)
5224 {
5225         return __perf_event_overflow(event, 1, data, regs);
5226 }
5227 
5228 /*
5229  * Generic software event infrastructure
5230  */
5231 
5232 struct swevent_htable {
5233         struct swevent_hlist            *swevent_hlist;
5234         struct mutex                    hlist_mutex;
5235         int                             hlist_refcount;
5236 
5237         /* Recursion avoidance in each contexts */
5238         int                             recursion[PERF_NR_CONTEXTS];
5239 };
5240 
5241 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
5242 
5243 /*
5244  * We directly increment event->count and keep a second value in
5245  * event->hw.period_left to count intervals. This period event
5246  * is kept in the range [-sample_period, 0] so that we can use the
5247  * sign as trigger.
5248  */
5249 
5250 u64 perf_swevent_set_period(struct perf_event *event)
5251 {
5252         struct hw_perf_event *hwc = &event->hw;
5253         u64 period = hwc->last_period;
5254         u64 nr, offset;
5255         s64 old, val;
5256 
5257         hwc->last_period = hwc->sample_period;
5258 
5259 again:
5260         old = val = local64_read(&hwc->period_left);
5261         if (val < 0)
5262                 return 0;
5263 
5264         nr = div64_u64(period + val, period);
5265         offset = nr * period;
5266         val -= offset;
5267         if (local64_cmpxchg(&hwc->period_left, old, val) != old)
5268                 goto again;
5269 
5270         return nr;
5271 }
5272 
5273 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
5274                                     struct perf_sample_data *data,
5275                                     struct pt_regs *regs)
5276 {
5277         struct hw_perf_event *hwc = &event->hw;
5278         int throttle = 0;
5279 
5280         if (!overflow)
5281                 overflow = perf_swevent_set_period(event);
5282 
5283         if (hwc->interrupts == MAX_INTERRUPTS)
5284                 return;
5285 
5286         for (; overflow; overflow--) {
5287                 if (__perf_event_overflow(event, throttle,
5288                                             data, regs)) {
5289                         /*
5290                          * We inhibit the overflow from happening when
5291                          * hwc->interrupts == MAX_INTERRUPTS.
5292                          */
5293                         break;
5294                 }
5295                 throttle = 1;
5296         }
5297 }
5298 
5299 static void perf_swevent_event(struct perf_event *event, u64 nr,
5300                                struct perf_sample_data *data,
5301                                struct pt_regs *regs)
5302 {
5303         struct hw_perf_event *hwc = &event->hw;
5304 
5305         local64_add(nr, &event->count);
5306 
5307         if (!regs)
5308                 return;
5309 
5310         if (!is_sampling_event(event))
5311                 return;
5312 
5313         if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
5314                 data->period = nr;
5315                 return perf_swevent_overflow(event, 1, data, regs);
5316         } else
5317                 data->period = event->hw.last_period;
5318 
5319         if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
5320                 return perf_swevent_overflow(event, 1, data, regs);
5321 
5322         if (local64_add_negative(nr, &hwc->period_left))
5323                 return;
5324 
5325         perf_swevent_overflow(event, 0, data, regs);
5326 }
5327 
5328 static int perf_exclude_event(struct perf_event *event,
5329                               struct pt_regs *regs)
5330 {
5331         if (event->hw.state & PERF_HES_STOPPED)
5332                 return 1;
5333 
5334         if (regs) {
5335                 if (event->attr.exclude_user && user_mode(regs))
5336                         return 1;
5337 
5338                 if (event->attr.exclude_kernel && !user_mode(regs))
5339                         return 1;
5340         }
5341 
5342         return 0;
5343 }
5344 
5345 static int perf_swevent_match(struct perf_event *event,
5346                                 enum perf_type_id type,
5347                                 u32 event_id,
5348                                 struct perf_sample_data *data,
5349                                 struct pt_regs *regs)
5350 {
5351         if (event->attr.type != type)
5352                 return 0;
5353 
5354         if (event->attr.config != event_id)
5355                 return 0;
5356 
5357         if (perf_exclude_event(event, regs))
5358                 return 0;
5359 
5360         return 1;
5361 }
5362 
5363 static inline u64 swevent_hash(u64 type, u32 event_id)
5364 {
5365         u64 val = event_id | (type << 32);
5366 
5367         return hash_64(val, SWEVENT_HLIST_BITS);
5368 }
5369 
5370 static inline struct hlist_head *
5371 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
5372 {
5373         u64 hash = swevent_hash(type, event_id);
5374 
5375         return &hlist->heads[hash];
5376 }
5377 
5378 /* For the read side: events when they trigger */
5379 static inline struct hlist_head *
5380 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
5381 {
5382         struct swevent_hlist *hlist;
5383 
5384         hlist = rcu_dereference(swhash->swevent_hlist);
5385         if (!hlist)
5386                 return NULL;
5387 
5388         return __find_swevent_head(hlist, type, event_id);
5389 }
5390 
5391 /* For the event head insertion and removal in the hlist */
5392 static inline struct hlist_head *
5393 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
5394 {
5395         struct swevent_hlist *hlist;
5396         u32 event_id = event->attr.config;
5397         u64 type = event->attr.type;
5398 
5399         /*
5400          * Event scheduling is always serialized against hlist allocation
5401          * and release. Which makes the protected version suitable here.
5402          * The context lock guarantees that.
5403          */
5404         hlist = rcu_dereference_protected(swhash->swevent_hlist,
5405                                           lockdep_is_held(&event->ctx->lock));
5406         if (!hlist)
5407                 return NULL;
5408 
5409         return __find_swevent_head(hlist, type, event_id);
5410 }
5411 
5412 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
5413                                     u64 nr,
5414                                     struct perf_sample_data *data,
5415                                     struct pt_regs *regs)
5416 {
5417         struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5418         struct perf_event *event;
5419         struct hlist_head *head;
5420 
5421         rcu_read_lock();
5422         head = find_swevent_head_rcu(swhash, type, event_id);
5423         if (!head)
5424                 goto end;
5425 
5426         hlist_for_each_entry_rcu(event, head, hlist_entry) {
5427                 if (perf_swevent_match(event, type, event_id, data, regs))
5428                         perf_swevent_event(event, nr, data, regs);
5429         }
5430 end:
5431         rcu_read_unlock();
5432 }
5433 
5434 int perf_swevent_get_recursion_context(void)
5435 {
5436         struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5437 
5438         return get_recursion_context(swhash->recursion);
5439 }
5440 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
5441 
5442 inline void perf_swevent_put_recursion_context(int rctx)
5443 {
5444         struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5445 
5446         put_recursion_context(swhash->recursion, rctx);
5447 }
5448 
5449 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
5450 {
5451         struct perf_sample_data data;
5452         int rctx;
5453 
5454         preempt_disable_notrace();
5455         rctx = perf_swevent_get_recursion_context();
5456         if (rctx < 0)
5457                 return;
5458 
5459         perf_sample_data_init(&data, addr, 0);
5460 
5461         do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
5462 
5463         perf_swevent_put_recursion_context(rctx);
5464         preempt_enable_notrace();
5465 }
5466 
5467 static void perf_swevent_read(struct perf_event *event)
5468 {
5469 }
5470 
5471 static int perf_swevent_add(struct perf_event *event, int flags)
5472 {
5473         struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
5474         struct hw_perf_event *hwc = &event->hw;
5475         struct hlist_head *head;
5476 
5477         if (is_sampling_event(event)) {
5478                 hwc->last_period = hwc->sample_period;
5479                 perf_swevent_set_period(event);
5480         }
5481 
5482         hwc->state = !(flags & PERF_EF_START);
5483 
5484         head = find_swevent_head(swhash, event);
5485         if (WARN_ON_ONCE(!head))
5486                 return -EINVAL;
5487 
5488         hlist_add_head_rcu(&event->hlist_entry, head);
5489 
5490         return 0;
5491 }
5492 
5493 static void perf_swevent_del(struct perf_event *event, int flags)
5494 {
5495         hlist_del_rcu(&event->hlist_entry);
5496 }
5497 
5498 static void perf_swevent_start(struct perf_event *event, int flags)
5499 {
5500         event->hw.state = 0;
5501 }
5502 
5503 static void perf_swevent_stop(struct perf_event *event, int flags)
5504 {
5505         event->hw.state = PERF_HES_STOPPED;
5506 }
5507 
5508 /* Deref the hlist from the update side */
5509 static inline struct swevent_hlist *
5510 swevent_hlist_deref(struct swevent_htable *swhash)
5511 {
5512         return rcu_dereference_protected(swhash->swevent_hlist,
5513                                          lockdep_is_held(&swhash->hlist_mutex));
5514 }
5515 
5516 static void swevent_hlist_release(struct swevent_htable *swhash)
5517 {
5518         struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
5519 
5520         if (!hlist)
5521                 return;
5522 
5523         rcu_assign_pointer(swhash->swevent_hlist, NULL);
5524         kfree_rcu(hlist, rcu_head);
5525 }
5526 
5527 static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
5528 {
5529         struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5530 
5531         mutex_lock(&swhash->hlist_mutex);
5532 
5533         if (!--swhash->hlist_refcount)
5534                 swevent_hlist_release(swhash);
5535 
5536         mutex_unlock(&swhash->hlist_mutex);
5537 }
5538 
5539 static void swevent_hlist_put(struct perf_event *event)
5540 {
5541         int cpu;
5542 
5543         if (event->cpu != -1) {
5544                 swevent_hlist_put_cpu(event, event->cpu);
5545                 return;
5546         }
5547 
5548         for_each_possible_cpu(cpu)
5549                 swevent_hlist_put_cpu(event, cpu);
5550 }
5551 
5552 static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
5553 {
5554         struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5555         int err = 0;
5556 
5557         mutex_lock(&swhash->hlist_mutex);
5558 
5559         if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5560                 struct swevent_hlist *hlist;
5561 
5562                 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5563                 if (!hlist) {
5564                         err = -ENOMEM;
5565                         goto exit;
5566                 }
5567                 rcu_assign_pointer(swhash->swevent_hlist, hlist);
5568         }
5569         swhash->hlist_refcount++;
5570 exit:
5571         mutex_unlock(&swhash->hlist_mutex);
5572 
5573         return err;
5574 }
5575 
5576 static int swevent_hlist_get(struct perf_event *event)
5577 {
5578         int err;
5579         int cpu, failed_cpu;
5580 
5581         if (event->cpu != -1)
5582                 return swevent_hlist_get_cpu(event, event->cpu);
5583 
5584         get_online_cpus();
5585         for_each_possible_cpu(cpu) {
5586                 err = swevent_hlist_get_cpu(event, cpu);
5587                 if (err) {
5588                         failed_cpu = cpu;
5589                         goto fail;
5590                 }
5591         }
5592         put_online_cpus();
5593 
5594         return 0;
5595 fail:
5596         for_each_possible_cpu(cpu) {
5597                 if (cpu == failed_cpu)
5598                         break;
5599                 swevent_hlist_put_cpu(event, cpu);
5600         }
5601 
5602         put_online_cpus();
5603         return err;
5604 }
5605 
5606 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5607 
5608 static void sw_perf_event_destroy(struct perf_event *event)
5609 {
5610         u64 event_id = event->attr.config;
5611 
5612         WARN_ON(event->parent);
5613 
5614         static_key_slow_dec(&perf_swevent_enabled[event_id]);
5615         swevent_hlist_put(event);
5616 }
5617 
5618 static int perf_swevent_init(struct perf_event *event)
5619 {
5620         u64 event_id = event->attr.config;
5621 
5622         if (event->attr.type != PERF_TYPE_SOFTWARE)
5623                 return -ENOENT;
5624 
5625         /*
5626          * no branch sampling for software events
5627          */
5628         if (has_branch_stack(event))
5629                 return -EOPNOTSUPP;
5630 
5631         switch (event_id) {
5632         case PERF_COUNT_SW_CPU_CLOCK:
5633         case PERF_COUNT_SW_TASK_CLOCK:
5634                 return -ENOENT;
5635 
5636         default:
5637                 break;
5638         }
5639 
5640         if (event_id >= PERF_COUNT_SW_MAX)
5641                 return -ENOENT;
5642 
5643         if (!event->parent) {
5644                 int err;
5645 
5646                 err = swevent_hlist_get(event);
5647                 if (err)
5648                         return err;
5649 
5650                 static_key_slow_inc(&perf_swevent_enabled[event_id]);
5651                 event->destroy = sw_perf_event_destroy;
5652         }
5653 
5654         return 0;
5655 }
5656 
5657 static int perf_swevent_event_idx(struct perf_event *event)
5658 {
5659         return 0;
5660 }
5661 
5662 static struct pmu perf_swevent = {
5663         .task_ctx_nr    = perf_sw_context,
5664 
5665         .event_init     = perf_swevent_init,
5666         .add            = perf_swevent_add,
5667         .del            = perf_swevent_del,
5668         .start          = perf_swevent_start,
5669         .stop           = perf_swevent_stop,
5670         .read           = perf_swevent_read,
5671 
5672         .event_idx      = perf_swevent_event_idx,
5673 };
5674 
5675 #ifdef CONFIG_EVENT_TRACING
5676 
5677 static int perf_tp_filter_match(struct perf_event *event,
5678                                 struct perf_sample_data *data)
5679 {
5680         void *record = data->raw->data;
5681 
5682         if (likely(!event->filter) || filter_match_preds(event->filter, record))
5683                 return 1;
5684         return 0;
5685 }
5686 
5687 static int perf_tp_event_match(struct perf_event *event,
5688                                 struct perf_sample_data *data,
5689                                 struct pt_regs *regs)
5690 {
5691         if (event->hw.state & PERF_HES_STOPPED)
5692                 return 0;
5693         /*
5694          * All tracepoints are from kernel-space.
5695          */
5696         if (event->attr.exclude_kernel)
5697                 return 0;
5698 
5699         if (!perf_tp_filter_match(event, data))
5700                 return 0;
5701 
5702         return 1;
5703 }
5704 
5705 void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
5706                    struct pt_regs *regs, struct hlist_head *head, int rctx,
5707                    struct task_struct *task)
5708 {
5709         struct perf_sample_data data;
5710         struct perf_event *event;
5711 
5712         struct perf_raw_record raw = {
5713                 .size = entry_size,
5714                 .data = record,
5715         };
5716 
5717         perf_sample_data_init(&data, addr, 0);
5718         data.raw = &raw;
5719 
5720         hlist_for_each_entry_rcu(event, head, hlist_entry) {
5721                 if (perf_tp_event_match(event, &data, regs))
5722                         perf_swevent_event(event, count, &data, regs);
5723         }
5724 
5725         /*
5726          * If we got specified a target task, also iterate its context and
5727          * deliver this event there too.
5728          */
5729         if (task && task != current) {
5730                 struct perf_event_context *ctx;
5731                 struct trace_entry *entry = record;
5732 
5733                 rcu_read_lock();
5734                 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
5735                 if (!ctx)
5736                         goto unlock;
5737 
5738                 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
5739                         if (event->attr.type != PERF_TYPE_TRACEPOINT)
5740                                 continue;
5741                         if (event->attr.config != entry->type)
5742                                 continue;
5743                         if (perf_tp_event_match(event, &data, regs))
5744                                 perf_swevent_event(event, count, &data, regs);
5745                 }
5746 unlock:
5747                 rcu_read_unlock();
5748         }
5749 
5750         perf_swevent_put_recursion_context(rctx);
5751 }
5752 EXPORT_SYMBOL_GPL(perf_tp_event);
5753 
5754 static void tp_perf_event_destroy(struct perf_event *event)
5755 {
5756         perf_trace_destroy(event);
5757 }
5758 
5759 static int perf_tp_event_init(struct perf_event *event)
5760 {
5761         int err;
5762 
5763         if (event->attr.type != PERF_TYPE_TRACEPOINT)
5764                 return -ENOENT;
5765 
5766         /*
5767          * no branch sampling for tracepoint events
5768          */
5769         if (has_branch_stack(event))
5770                 return -EOPNOTSUPP;
5771 
5772         err = perf_trace_init(event);
5773         if (err)
5774                 return err;
5775 
5776         event->destroy = tp_perf_event_destroy;
5777 
5778         return 0;
5779 }
5780 
5781 static struct pmu perf_tracepoint = {
5782         .task_ctx_nr    = perf_sw_context,
5783 
5784         .event_init     = perf_tp_event_init,
5785         .add            = perf_trace_add,
5786         .del            = perf_trace_del,
5787         .start          = perf_swevent_start,
5788         .stop           = perf_swevent_stop,
5789         .read           = perf_swevent_read,
5790 
5791         .event_idx      = perf_swevent_event_idx,
5792 };
5793 
5794 static inline void perf_tp_register(void)
5795 {
5796         perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5797 }
5798 
5799 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5800 {
5801         char *filter_str;
5802         int ret;
5803 
5804         if (event->attr.type != PERF_TYPE_TRACEPOINT)
5805                 return -EINVAL;
5806 
5807         filter_str = strndup_user(arg, PAGE_SIZE);
5808         if (IS_ERR(filter_str))
5809                 return PTR_ERR(filter_str);
5810 
5811         ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5812 
5813         kfree(filter_str);
5814         return ret;
5815 }
5816 
5817 static void perf_event_free_filter(struct perf_event *event)
5818 {
5819         ftrace_profile_free_filter(event);
5820 }
5821 
5822 #else
5823 
5824 static inline void perf_tp_register(void)
5825 {
5826 }
5827 
5828 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5829 {
5830         return -ENOENT;
5831 }
5832 
5833 static void perf_event_free_filter(struct perf_event *event)
5834 {
5835 }
5836 
5837 #endif /* CONFIG_EVENT_TRACING */
5838 
5839 #ifdef CONFIG_HAVE_HW_BREAKPOINT
5840 void perf_bp_event(struct perf_event *bp, void *data)
5841 {
5842         struct perf_sample_data sample;
5843         struct pt_regs *regs = data;
5844 
5845         perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
5846 
5847         if (!bp->hw.state && !perf_exclude_event(bp, regs))
5848                 perf_swevent_event(bp, 1, &sample, regs);
5849 }
5850 #endif
5851 
5852 /*
5853  * hrtimer based swevent callback
5854  */
5855 
5856 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5857 {
5858         enum hrtimer_restart ret = HRTIMER_RESTART;
5859         struct perf_sample_data data;
5860         struct pt_regs *regs;
5861         struct perf_event *event;
5862         u64 period;
5863 
5864         event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5865 
5866         if (event->state != PERF_EVENT_STATE_ACTIVE)
5867                 return HRTIMER_NORESTART;
5868 
5869         event->pmu->read(event);
5870 
5871         perf_sample_data_init(&data, 0, event->hw.last_period);
5872         regs = get_irq_regs();
5873 
5874         if (regs && !perf_exclude_event(event, regs)) {
5875                 if (!(event->attr.exclude_idle && is_idle_task(current)))
5876                         if (__perf_event_overflow(event, 1, &data, regs))
5877                                 ret = HRTIMER_NORESTART;
5878         }
5879 
5880         period = max_t(u64, 10000, event->hw.sample_period);
5881         hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5882 
5883         return ret;
5884 }
5885 
5886 static void perf_swevent_start_hrtimer(struct perf_event *event)
5887 {
5888         struct hw_perf_event *hwc = &event->hw;
5889         s64 period;
5890 
5891         if (!is_sampling_event(event))
5892                 return;
5893 
5894         period = local64_read(&hwc->period_left);
5895         if (period) {
5896                 if (period < 0)
5897                         period = 10000;
5898 
5899                 local64_set(&hwc->period_left, 0);
5900         } else {
5901                 period = max_t(u64, 10000, hwc->sample_period);
5902         }
5903         __hrtimer_start_range_ns(&hwc->hrtimer,
5904                                 ns_to_ktime(period), 0,
5905                                 HRTIMER_MODE_REL_PINNED, 0);
5906 }
5907 
5908 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5909 {
5910         struct hw_perf_event *hwc = &event->hw;
5911 
5912         if (is_sampling_event(event)) {
5913                 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5914                 local64_set(&hwc->period_left, ktime_to_ns(remaining));
5915 
5916                 hrtimer_cancel(&hwc->hrtimer);
5917         }
5918 }
5919 
5920 static void perf_swevent_init_hrtimer(struct perf_event *event)
5921 {
5922         struct hw_perf_event *hwc = &event->hw;
5923 
5924         if (!is_sampling_event(event))
5925                 return;
5926 
5927         hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5928         hwc->hrtimer.function = perf_swevent_hrtimer;
5929 
5930         /*
5931          * Since hrtimers have a fixed rate, we can do a static freq->period
5932          * mapping and avoid the whole period adjust feedback stuff.
5933          */
5934         if (event->attr.freq) {
5935                 long freq = event->attr.sample_freq;
5936 
5937                 event->attr.sample_period = NSEC_PER_SEC / freq;
5938                 hwc->sample_period = event->attr.sample_period;
5939                 local64_set(&hwc->period_left, hwc->sample_period);
5940                 hwc->last_period = hwc->sample_period;
5941                 event->attr.freq = 0;
5942         }
5943 }
5944 
5945 /*
5946  * Software event: cpu wall time clock
5947  */
5948 
5949 static void cpu_clock_event_update(struct perf_event *event)
5950 {
5951         s64 prev;
5952         u64 now;
5953 
5954         now = local_clock();
5955         prev = local64_xchg(&event->hw.prev_count, now);
5956         local64_add(now - prev, &event->count);
5957 }
5958 
5959 static void cpu_clock_event_start(struct perf_event *event, int flags)
5960 {
5961         local64_set(&event->hw.prev_count, local_clock());
5962         perf_swevent_start_hrtimer(event);
5963 }