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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_events.c

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  1 /*
  2  * event tracer
  3  *
  4  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
  5  *
  6  *  - Added format output of fields of the trace point.
  7  *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
  8  *
  9  */
 10 
 11 #define pr_fmt(fmt) fmt
 12 
 13 #include <linux/workqueue.h>
 14 #include <linux/spinlock.h>
 15 #include <linux/kthread.h>
 16 #include <linux/tracefs.h>
 17 #include <linux/uaccess.h>
 18 #include <linux/module.h>
 19 #include <linux/ctype.h>
 20 #include <linux/sort.h>
 21 #include <linux/slab.h>
 22 #include <linux/delay.h>
 23 
 24 #include <trace/events/sched.h>
 25 
 26 #include <asm/setup.h>
 27 
 28 #include "trace_output.h"
 29 
 30 #undef TRACE_SYSTEM
 31 #define TRACE_SYSTEM "TRACE_SYSTEM"
 32 
 33 DEFINE_MUTEX(event_mutex);
 34 
 35 LIST_HEAD(ftrace_events);
 36 static LIST_HEAD(ftrace_generic_fields);
 37 static LIST_HEAD(ftrace_common_fields);
 38 
 39 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
 40 
 41 static struct kmem_cache *field_cachep;
 42 static struct kmem_cache *file_cachep;
 43 
 44 static inline int system_refcount(struct event_subsystem *system)
 45 {
 46         return system->ref_count;
 47 }
 48 
 49 static int system_refcount_inc(struct event_subsystem *system)
 50 {
 51         return system->ref_count++;
 52 }
 53 
 54 static int system_refcount_dec(struct event_subsystem *system)
 55 {
 56         return --system->ref_count;
 57 }
 58 
 59 /* Double loops, do not use break, only goto's work */
 60 #define do_for_each_event_file(tr, file)                        \
 61         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
 62                 list_for_each_entry(file, &tr->events, list)
 63 
 64 #define do_for_each_event_file_safe(tr, file)                   \
 65         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
 66                 struct trace_event_file *___n;                          \
 67                 list_for_each_entry_safe(file, ___n, &tr->events, list)
 68 
 69 #define while_for_each_event_file()             \
 70         }
 71 
 72 static struct list_head *
 73 trace_get_fields(struct trace_event_call *event_call)
 74 {
 75         if (!event_call->class->get_fields)
 76                 return &event_call->class->fields;
 77         return event_call->class->get_fields(event_call);
 78 }
 79 
 80 static struct ftrace_event_field *
 81 __find_event_field(struct list_head *head, char *name)
 82 {
 83         struct ftrace_event_field *field;
 84 
 85         list_for_each_entry(field, head, link) {
 86                 if (!strcmp(field->name, name))
 87                         return field;
 88         }
 89 
 90         return NULL;
 91 }
 92 
 93 struct ftrace_event_field *
 94 trace_find_event_field(struct trace_event_call *call, char *name)
 95 {
 96         struct ftrace_event_field *field;
 97         struct list_head *head;
 98 
 99         head = trace_get_fields(call);
100         field = __find_event_field(head, name);
101         if (field)
102                 return field;
103 
104         field = __find_event_field(&ftrace_generic_fields, name);
105         if (field)
106                 return field;
107 
108         return __find_event_field(&ftrace_common_fields, name);
109 }
110 
111 static int __trace_define_field(struct list_head *head, const char *type,
112                                 const char *name, int offset, int size,
113                                 int is_signed, int filter_type)
114 {
115         struct ftrace_event_field *field;
116 
117         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
118         if (!field)
119                 return -ENOMEM;
120 
121         field->name = name;
122         field->type = type;
123 
124         if (filter_type == FILTER_OTHER)
125                 field->filter_type = filter_assign_type(type);
126         else
127                 field->filter_type = filter_type;
128 
129         field->offset = offset;
130         field->size = size;
131         field->is_signed = is_signed;
132 
133         list_add(&field->link, head);
134 
135         return 0;
136 }
137 
138 int trace_define_field(struct trace_event_call *call, const char *type,
139                        const char *name, int offset, int size, int is_signed,
140                        int filter_type)
141 {
142         struct list_head *head;
143 
144         if (WARN_ON(!call->class))
145                 return 0;
146 
147         head = trace_get_fields(call);
148         return __trace_define_field(head, type, name, offset, size,
149                                     is_signed, filter_type);
150 }
151 EXPORT_SYMBOL_GPL(trace_define_field);
152 
153 #define __generic_field(type, item, filter_type)                        \
154         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
155                                    #item, 0, 0, is_signed_type(type),   \
156                                    filter_type);                        \
157         if (ret)                                                        \
158                 return ret;
159 
160 #define __common_field(type, item)                                      \
161         ret = __trace_define_field(&ftrace_common_fields, #type,        \
162                                    "common_" #item,                     \
163                                    offsetof(typeof(ent), item),         \
164                                    sizeof(ent.item),                    \
165                                    is_signed_type(type), FILTER_OTHER); \
166         if (ret)                                                        \
167                 return ret;
168 
169 static int trace_define_generic_fields(void)
170 {
171         int ret;
172 
173         __generic_field(int, CPU, FILTER_CPU);
174         __generic_field(int, cpu, FILTER_CPU);
175         __generic_field(char *, COMM, FILTER_COMM);
176         __generic_field(char *, comm, FILTER_COMM);
177 
178         return ret;
179 }
180 
181 static int trace_define_common_fields(void)
182 {
183         int ret;
184         struct trace_entry ent;
185 
186         __common_field(unsigned short, type);
187         __common_field(unsigned char, flags);
188         __common_field(unsigned char, preempt_count);
189         __common_field(int, pid);
190 
191         return ret;
192 }
193 
194 static void trace_destroy_fields(struct trace_event_call *call)
195 {
196         struct ftrace_event_field *field, *next;
197         struct list_head *head;
198 
199         head = trace_get_fields(call);
200         list_for_each_entry_safe(field, next, head, link) {
201                 list_del(&field->link);
202                 kmem_cache_free(field_cachep, field);
203         }
204 }
205 
206 /*
207  * run-time version of trace_event_get_offsets_<call>() that returns the last
208  * accessible offset of trace fields excluding __dynamic_array bytes
209  */
210 int trace_event_get_offsets(struct trace_event_call *call)
211 {
212         struct ftrace_event_field *tail;
213         struct list_head *head;
214 
215         head = trace_get_fields(call);
216         /*
217          * head->next points to the last field with the largest offset,
218          * since it was added last by trace_define_field()
219          */
220         tail = list_first_entry(head, struct ftrace_event_field, link);
221         return tail->offset + tail->size;
222 }
223 
224 int trace_event_raw_init(struct trace_event_call *call)
225 {
226         int id;
227 
228         id = register_trace_event(&call->event);
229         if (!id)
230                 return -ENODEV;
231 
232         return 0;
233 }
234 EXPORT_SYMBOL_GPL(trace_event_raw_init);
235 
236 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
237 {
238         struct trace_array *tr = trace_file->tr;
239         struct trace_array_cpu *data;
240         struct trace_pid_list *pid_list;
241 
242         pid_list = rcu_dereference_sched(tr->filtered_pids);
243         if (!pid_list)
244                 return false;
245 
246         data = this_cpu_ptr(tr->trace_buffer.data);
247 
248         return data->ignore_pid;
249 }
250 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
251 
252 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
253                                  struct trace_event_file *trace_file,
254                                  unsigned long len)
255 {
256         struct trace_event_call *event_call = trace_file->event_call;
257 
258         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
259             trace_event_ignore_this_pid(trace_file))
260                 return NULL;
261 
262         local_save_flags(fbuffer->flags);
263         fbuffer->pc = preempt_count();
264         /*
265          * If CONFIG_PREEMPT is enabled, then the tracepoint itself disables
266          * preemption (adding one to the preempt_count). Since we are
267          * interested in the preempt_count at the time the tracepoint was
268          * hit, we need to subtract one to offset the increment.
269          */
270         if (IS_ENABLED(CONFIG_PREEMPT))
271                 fbuffer->pc--;
272         fbuffer->trace_file = trace_file;
273 
274         fbuffer->event =
275                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
276                                                 event_call->event.type, len,
277                                                 fbuffer->flags, fbuffer->pc);
278         if (!fbuffer->event)
279                 return NULL;
280 
281         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
282         return fbuffer->entry;
283 }
284 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
285 
286 int trace_event_reg(struct trace_event_call *call,
287                     enum trace_reg type, void *data)
288 {
289         struct trace_event_file *file = data;
290 
291         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
292         switch (type) {
293         case TRACE_REG_REGISTER:
294                 return tracepoint_probe_register(call->tp,
295                                                  call->class->probe,
296                                                  file);
297         case TRACE_REG_UNREGISTER:
298                 tracepoint_probe_unregister(call->tp,
299                                             call->class->probe,
300                                             file);
301                 return 0;
302 
303 #ifdef CONFIG_PERF_EVENTS
304         case TRACE_REG_PERF_REGISTER:
305                 return tracepoint_probe_register(call->tp,
306                                                  call->class->perf_probe,
307                                                  call);
308         case TRACE_REG_PERF_UNREGISTER:
309                 tracepoint_probe_unregister(call->tp,
310                                             call->class->perf_probe,
311                                             call);
312                 return 0;
313         case TRACE_REG_PERF_OPEN:
314         case TRACE_REG_PERF_CLOSE:
315         case TRACE_REG_PERF_ADD:
316         case TRACE_REG_PERF_DEL:
317                 return 0;
318 #endif
319         }
320         return 0;
321 }
322 EXPORT_SYMBOL_GPL(trace_event_reg);
323 
324 void trace_event_enable_cmd_record(bool enable)
325 {
326         struct trace_event_file *file;
327         struct trace_array *tr;
328 
329         mutex_lock(&event_mutex);
330         do_for_each_event_file(tr, file) {
331 
332                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
333                         continue;
334 
335                 if (enable) {
336                         tracing_start_cmdline_record();
337                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
338                 } else {
339                         tracing_stop_cmdline_record();
340                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
341                 }
342         } while_for_each_event_file();
343         mutex_unlock(&event_mutex);
344 }
345 
346 void trace_event_enable_tgid_record(bool enable)
347 {
348         struct trace_event_file *file;
349         struct trace_array *tr;
350 
351         mutex_lock(&event_mutex);
352         do_for_each_event_file(tr, file) {
353                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
354                         continue;
355 
356                 if (enable) {
357                         tracing_start_tgid_record();
358                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
359                 } else {
360                         tracing_stop_tgid_record();
361                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
362                                   &file->flags);
363                 }
364         } while_for_each_event_file();
365         mutex_unlock(&event_mutex);
366 }
367 
368 static int __ftrace_event_enable_disable(struct trace_event_file *file,
369                                          int enable, int soft_disable)
370 {
371         struct trace_event_call *call = file->event_call;
372         struct trace_array *tr = file->tr;
373         unsigned long file_flags = file->flags;
374         int ret = 0;
375         int disable;
376 
377         switch (enable) {
378         case 0:
379                 /*
380                  * When soft_disable is set and enable is cleared, the sm_ref
381                  * reference counter is decremented. If it reaches 0, we want
382                  * to clear the SOFT_DISABLED flag but leave the event in the
383                  * state that it was. That is, if the event was enabled and
384                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
385                  * is set we do not want the event to be enabled before we
386                  * clear the bit.
387                  *
388                  * When soft_disable is not set but the SOFT_MODE flag is,
389                  * we do nothing. Do not disable the tracepoint, otherwise
390                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
391                  */
392                 if (soft_disable) {
393                         if (atomic_dec_return(&file->sm_ref) > 0)
394                                 break;
395                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
396                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
397                 } else
398                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
399 
400                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
401                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
402                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
403                                 tracing_stop_cmdline_record();
404                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
405                         }
406 
407                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
408                                 tracing_stop_tgid_record();
409                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
410                         }
411 
412                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
413                 }
414                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
415                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
416                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
417                 else
418                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
419                 break;
420         case 1:
421                 /*
422                  * When soft_disable is set and enable is set, we want to
423                  * register the tracepoint for the event, but leave the event
424                  * as is. That means, if the event was already enabled, we do
425                  * nothing (but set SOFT_MODE). If the event is disabled, we
426                  * set SOFT_DISABLED before enabling the event tracepoint, so
427                  * it still seems to be disabled.
428                  */
429                 if (!soft_disable)
430                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
431                 else {
432                         if (atomic_inc_return(&file->sm_ref) > 1)
433                                 break;
434                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
435                 }
436 
437                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
438                         bool cmd = false, tgid = false;
439 
440                         /* Keep the event disabled, when going to SOFT_MODE. */
441                         if (soft_disable)
442                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
443 
444                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
445                                 cmd = true;
446                                 tracing_start_cmdline_record();
447                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
448                         }
449 
450                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
451                                 tgid = true;
452                                 tracing_start_tgid_record();
453                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
454                         }
455 
456                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
457                         if (ret) {
458                                 if (cmd)
459                                         tracing_stop_cmdline_record();
460                                 if (tgid)
461                                         tracing_stop_tgid_record();
462                                 pr_info("event trace: Could not enable event "
463                                         "%s\n", trace_event_name(call));
464                                 break;
465                         }
466                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
467 
468                         /* WAS_ENABLED gets set but never cleared. */
469                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
470                 }
471                 break;
472         }
473 
474         /* Enable or disable use of trace_buffered_event */
475         if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
476             (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
477                 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
478                         trace_buffered_event_enable();
479                 else
480                         trace_buffered_event_disable();
481         }
482 
483         return ret;
484 }
485 
486 int trace_event_enable_disable(struct trace_event_file *file,
487                                int enable, int soft_disable)
488 {
489         return __ftrace_event_enable_disable(file, enable, soft_disable);
490 }
491 
492 static int ftrace_event_enable_disable(struct trace_event_file *file,
493                                        int enable)
494 {
495         return __ftrace_event_enable_disable(file, enable, 0);
496 }
497 
498 static void ftrace_clear_events(struct trace_array *tr)
499 {
500         struct trace_event_file *file;
501 
502         mutex_lock(&event_mutex);
503         list_for_each_entry(file, &tr->events, list) {
504                 ftrace_event_enable_disable(file, 0);
505         }
506         mutex_unlock(&event_mutex);
507 }
508 
509 static void
510 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
511 {
512         struct trace_pid_list *pid_list;
513         struct trace_array *tr = data;
514 
515         pid_list = rcu_dereference_sched(tr->filtered_pids);
516         trace_filter_add_remove_task(pid_list, NULL, task);
517 }
518 
519 static void
520 event_filter_pid_sched_process_fork(void *data,
521                                     struct task_struct *self,
522                                     struct task_struct *task)
523 {
524         struct trace_pid_list *pid_list;
525         struct trace_array *tr = data;
526 
527         pid_list = rcu_dereference_sched(tr->filtered_pids);
528         trace_filter_add_remove_task(pid_list, self, task);
529 }
530 
531 void trace_event_follow_fork(struct trace_array *tr, bool enable)
532 {
533         if (enable) {
534                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
535                                                        tr, INT_MIN);
536                 register_trace_prio_sched_process_exit(event_filter_pid_sched_process_exit,
537                                                        tr, INT_MAX);
538         } else {
539                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
540                                                     tr);
541                 unregister_trace_sched_process_exit(event_filter_pid_sched_process_exit,
542                                                     tr);
543         }
544 }
545 
546 static void
547 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
548                     struct task_struct *prev, struct task_struct *next)
549 {
550         struct trace_array *tr = data;
551         struct trace_pid_list *pid_list;
552 
553         pid_list = rcu_dereference_sched(tr->filtered_pids);
554 
555         this_cpu_write(tr->trace_buffer.data->ignore_pid,
556                        trace_ignore_this_task(pid_list, prev) &&
557                        trace_ignore_this_task(pid_list, next));
558 }
559 
560 static void
561 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
562                     struct task_struct *prev, struct task_struct *next)
563 {
564         struct trace_array *tr = data;
565         struct trace_pid_list *pid_list;
566 
567         pid_list = rcu_dereference_sched(tr->filtered_pids);
568 
569         this_cpu_write(tr->trace_buffer.data->ignore_pid,
570                        trace_ignore_this_task(pid_list, next));
571 }
572 
573 static void
574 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
575 {
576         struct trace_array *tr = data;
577         struct trace_pid_list *pid_list;
578 
579         /* Nothing to do if we are already tracing */
580         if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
581                 return;
582 
583         pid_list = rcu_dereference_sched(tr->filtered_pids);
584 
585         this_cpu_write(tr->trace_buffer.data->ignore_pid,
586                        trace_ignore_this_task(pid_list, task));
587 }
588 
589 static void
590 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
591 {
592         struct trace_array *tr = data;
593         struct trace_pid_list *pid_list;
594 
595         /* Nothing to do if we are not tracing */
596         if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
597                 return;
598 
599         pid_list = rcu_dereference_sched(tr->filtered_pids);
600 
601         /* Set tracing if current is enabled */
602         this_cpu_write(tr->trace_buffer.data->ignore_pid,
603                        trace_ignore_this_task(pid_list, current));
604 }
605 
606 static void __ftrace_clear_event_pids(struct trace_array *tr)
607 {
608         struct trace_pid_list *pid_list;
609         struct trace_event_file *file;
610         int cpu;
611 
612         pid_list = rcu_dereference_protected(tr->filtered_pids,
613                                              lockdep_is_held(&event_mutex));
614         if (!pid_list)
615                 return;
616 
617         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
618         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
619 
620         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
621         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
622 
623         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
624         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
625 
626         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
627         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
628 
629         list_for_each_entry(file, &tr->events, list) {
630                 clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
631         }
632 
633         for_each_possible_cpu(cpu)
634                 per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false;
635 
636         rcu_assign_pointer(tr->filtered_pids, NULL);
637 
638         /* Wait till all users are no longer using pid filtering */
639         synchronize_sched();
640 
641         trace_free_pid_list(pid_list);
642 }
643 
644 static void ftrace_clear_event_pids(struct trace_array *tr)
645 {
646         mutex_lock(&event_mutex);
647         __ftrace_clear_event_pids(tr);
648         mutex_unlock(&event_mutex);
649 }
650 
651 static void __put_system(struct event_subsystem *system)
652 {
653         struct event_filter *filter = system->filter;
654 
655         WARN_ON_ONCE(system_refcount(system) == 0);
656         if (system_refcount_dec(system))
657                 return;
658 
659         list_del(&system->list);
660 
661         if (filter) {
662                 kfree(filter->filter_string);
663                 kfree(filter);
664         }
665         kfree_const(system->name);
666         kfree(system);
667 }
668 
669 static void __get_system(struct event_subsystem *system)
670 {
671         WARN_ON_ONCE(system_refcount(system) == 0);
672         system_refcount_inc(system);
673 }
674 
675 static void __get_system_dir(struct trace_subsystem_dir *dir)
676 {
677         WARN_ON_ONCE(dir->ref_count == 0);
678         dir->ref_count++;
679         __get_system(dir->subsystem);
680 }
681 
682 static void __put_system_dir(struct trace_subsystem_dir *dir)
683 {
684         WARN_ON_ONCE(dir->ref_count == 0);
685         /* If the subsystem is about to be freed, the dir must be too */
686         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
687 
688         __put_system(dir->subsystem);
689         if (!--dir->ref_count)
690                 kfree(dir);
691 }
692 
693 static void put_system(struct trace_subsystem_dir *dir)
694 {
695         mutex_lock(&event_mutex);
696         __put_system_dir(dir);
697         mutex_unlock(&event_mutex);
698 }
699 
700 static void remove_subsystem(struct trace_subsystem_dir *dir)
701 {
702         if (!dir)
703                 return;
704 
705         if (!--dir->nr_events) {
706                 tracefs_remove_recursive(dir->entry);
707                 list_del(&dir->list);
708                 __put_system_dir(dir);
709         }
710 }
711 
712 static void remove_event_file_dir(struct trace_event_file *file)
713 {
714         struct dentry *dir = file->dir;
715         struct dentry *child;
716 
717         if (dir) {
718                 spin_lock(&dir->d_lock);        /* probably unneeded */
719                 list_for_each_entry(child, &dir->d_subdirs, d_child) {
720                         if (d_really_is_positive(child))        /* probably unneeded */
721                                 d_inode(child)->i_private = NULL;
722                 }
723                 spin_unlock(&dir->d_lock);
724 
725                 tracefs_remove_recursive(dir);
726         }
727 
728         list_del(&file->list);
729         remove_subsystem(file->system);
730         free_event_filter(file->filter);
731         kmem_cache_free(file_cachep, file);
732 }
733 
734 /*
735  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
736  */
737 static int
738 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
739                               const char *sub, const char *event, int set)
740 {
741         struct trace_event_file *file;
742         struct trace_event_call *call;
743         const char *name;
744         int ret = -EINVAL;
745         int eret = 0;
746 
747         list_for_each_entry(file, &tr->events, list) {
748 
749                 call = file->event_call;
750                 name = trace_event_name(call);
751 
752                 if (!name || !call->class || !call->class->reg)
753                         continue;
754 
755                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
756                         continue;
757 
758                 if (match &&
759                     strcmp(match, name) != 0 &&
760                     strcmp(match, call->class->system) != 0)
761                         continue;
762 
763                 if (sub && strcmp(sub, call->class->system) != 0)
764                         continue;
765 
766                 if (event && strcmp(event, name) != 0)
767                         continue;
768 
769                 ret = ftrace_event_enable_disable(file, set);
770 
771                 /*
772                  * Save the first error and return that. Some events
773                  * may still have been enabled, but let the user
774                  * know that something went wrong.
775                  */
776                 if (ret && !eret)
777                         eret = ret;
778 
779                 ret = eret;
780         }
781 
782         return ret;
783 }
784 
785 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
786                                   const char *sub, const char *event, int set)
787 {
788         int ret;
789 
790         mutex_lock(&event_mutex);
791         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
792         mutex_unlock(&event_mutex);
793 
794         return ret;
795 }
796 
797 static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
798 {
799         char *event = NULL, *sub = NULL, *match;
800         int ret;
801 
802         /*
803          * The buf format can be <subsystem>:<event-name>
804          *  *:<event-name> means any event by that name.
805          *  :<event-name> is the same.
806          *
807          *  <subsystem>:* means all events in that subsystem
808          *  <subsystem>: means the same.
809          *
810          *  <name> (no ':') means all events in a subsystem with
811          *  the name <name> or any event that matches <name>
812          */
813 
814         match = strsep(&buf, ":");
815         if (buf) {
816                 sub = match;
817                 event = buf;
818                 match = NULL;
819 
820                 if (!strlen(sub) || strcmp(sub, "*") == 0)
821                         sub = NULL;
822                 if (!strlen(event) || strcmp(event, "*") == 0)
823                         event = NULL;
824         }
825 
826         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
827 
828         /* Put back the colon to allow this to be called again */
829         if (buf)
830                 *(buf - 1) = ':';
831 
832         return ret;
833 }
834 
835 /**
836  * trace_set_clr_event - enable or disable an event
837  * @system: system name to match (NULL for any system)
838  * @event: event name to match (NULL for all events, within system)
839  * @set: 1 to enable, 0 to disable
840  *
841  * This is a way for other parts of the kernel to enable or disable
842  * event recording.
843  *
844  * Returns 0 on success, -EINVAL if the parameters do not match any
845  * registered events.
846  */
847 int trace_set_clr_event(const char *system, const char *event, int set)
848 {
849         struct trace_array *tr = top_trace_array();
850 
851         if (!tr)
852                 return -ENODEV;
853 
854         return __ftrace_set_clr_event(tr, NULL, system, event, set);
855 }
856 EXPORT_SYMBOL_GPL(trace_set_clr_event);
857 
858 /* 128 should be much more than enough */
859 #define EVENT_BUF_SIZE          127
860 
861 static ssize_t
862 ftrace_event_write(struct file *file, const char __user *ubuf,
863                    size_t cnt, loff_t *ppos)
864 {
865         struct trace_parser parser;
866         struct seq_file *m = file->private_data;
867         struct trace_array *tr = m->private;
868         ssize_t read, ret;
869 
870         if (!cnt)
871                 return 0;
872 
873         ret = tracing_update_buffers();
874         if (ret < 0)
875                 return ret;
876 
877         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
878                 return -ENOMEM;
879 
880         read = trace_get_user(&parser, ubuf, cnt, ppos);
881 
882         if (read >= 0 && trace_parser_loaded((&parser))) {
883                 int set = 1;
884 
885                 if (*parser.buffer == '!')
886                         set = 0;
887 
888                 parser.buffer[parser.idx] = 0;
889 
890                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
891                 if (ret)
892                         goto out_put;
893         }
894 
895         ret = read;
896 
897  out_put:
898         trace_parser_put(&parser);
899 
900         return ret;
901 }
902 
903 static void *
904 t_next(struct seq_file *m, void *v, loff_t *pos)
905 {
906         struct trace_event_file *file = v;
907         struct trace_event_call *call;
908         struct trace_array *tr = m->private;
909 
910         (*pos)++;
911 
912         list_for_each_entry_continue(file, &tr->events, list) {
913                 call = file->event_call;
914                 /*
915                  * The ftrace subsystem is for showing formats only.
916                  * They can not be enabled or disabled via the event files.
917                  */
918                 if (call->class && call->class->reg &&
919                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
920                         return file;
921         }
922 
923         return NULL;
924 }
925 
926 static void *t_start(struct seq_file *m, loff_t *pos)
927 {
928         struct trace_event_file *file;
929         struct trace_array *tr = m->private;
930         loff_t l;
931 
932         mutex_lock(&event_mutex);
933 
934         file = list_entry(&tr->events, struct trace_event_file, list);
935         for (l = 0; l <= *pos; ) {
936                 file = t_next(m, file, &l);
937                 if (!file)
938                         break;
939         }
940         return file;
941 }
942 
943 static void *
944 s_next(struct seq_file *m, void *v, loff_t *pos)
945 {
946         struct trace_event_file *file = v;
947         struct trace_array *tr = m->private;
948 
949         (*pos)++;
950 
951         list_for_each_entry_continue(file, &tr->events, list) {
952                 if (file->flags & EVENT_FILE_FL_ENABLED)
953                         return file;
954         }
955 
956         return NULL;
957 }
958 
959 static void *s_start(struct seq_file *m, loff_t *pos)
960 {
961         struct trace_event_file *file;
962         struct trace_array *tr = m->private;
963         loff_t l;
964 
965         mutex_lock(&event_mutex);
966 
967         file = list_entry(&tr->events, struct trace_event_file, list);
968         for (l = 0; l <= *pos; ) {
969                 file = s_next(m, file, &l);
970                 if (!file)
971                         break;
972         }
973         return file;
974 }
975 
976 static int t_show(struct seq_file *m, void *v)
977 {
978         struct trace_event_file *file = v;
979         struct trace_event_call *call = file->event_call;
980 
981         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
982                 seq_printf(m, "%s:", call->class->system);
983         seq_printf(m, "%s\n", trace_event_name(call));
984 
985         return 0;
986 }
987 
988 static void t_stop(struct seq_file *m, void *p)
989 {
990         mutex_unlock(&event_mutex);
991 }
992 
993 static void *
994 p_next(struct seq_file *m, void *v, loff_t *pos)
995 {
996         struct trace_array *tr = m->private;
997         struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
998 
999         return trace_pid_next(pid_list, v, pos);
1000 }
1001 
1002 static void *p_start(struct seq_file *m, loff_t *pos)
1003         __acquires(RCU)
1004 {
1005         struct trace_pid_list *pid_list;
1006         struct trace_array *tr = m->private;
1007 
1008         /*
1009          * Grab the mutex, to keep calls to p_next() having the same
1010          * tr->filtered_pids as p_start() has.
1011          * If we just passed the tr->filtered_pids around, then RCU would
1012          * have been enough, but doing that makes things more complex.
1013          */
1014         mutex_lock(&event_mutex);
1015         rcu_read_lock_sched();
1016 
1017         pid_list = rcu_dereference_sched(tr->filtered_pids);
1018 
1019         if (!pid_list)
1020                 return NULL;
1021 
1022         return trace_pid_start(pid_list, pos);
1023 }
1024 
1025 static void p_stop(struct seq_file *m, void *p)
1026         __releases(RCU)
1027 {
1028         rcu_read_unlock_sched();
1029         mutex_unlock(&event_mutex);
1030 }
1031 
1032 static ssize_t
1033 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1034                   loff_t *ppos)
1035 {
1036         struct trace_event_file *file;
1037         unsigned long flags;
1038         char buf[4] = "";
1039 
1040         mutex_lock(&event_mutex);
1041         file = event_file_data(filp);
1042         if (likely(file))
1043                 flags = file->flags;
1044         mutex_unlock(&event_mutex);
1045 
1046         if (!file)
1047                 return -ENODEV;
1048 
1049         if (flags & EVENT_FILE_FL_ENABLED &&
1050             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1051                 strcpy(buf, "1");
1052 
1053         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1054             flags & EVENT_FILE_FL_SOFT_MODE)
1055                 strcat(buf, "*");
1056 
1057         strcat(buf, "\n");
1058 
1059         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1060 }
1061 
1062 static ssize_t
1063 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1064                    loff_t *ppos)
1065 {
1066         struct trace_event_file *file;
1067         unsigned long val;
1068         int ret;
1069 
1070         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1071         if (ret)
1072                 return ret;
1073 
1074         ret = tracing_update_buffers();
1075         if (ret < 0)
1076                 return ret;
1077 
1078         switch (val) {
1079         case 0:
1080         case 1:
1081                 ret = -ENODEV;
1082                 mutex_lock(&event_mutex);
1083                 file = event_file_data(filp);
1084                 if (likely(file))
1085                         ret = ftrace_event_enable_disable(file, val);
1086                 mutex_unlock(&event_mutex);
1087                 break;
1088 
1089         default:
1090                 return -EINVAL;
1091         }
1092 
1093         *ppos += cnt;
1094 
1095         return ret ? ret : cnt;
1096 }
1097 
1098 static ssize_t
1099 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1100                    loff_t *ppos)
1101 {
1102         const char set_to_char[4] = { '?', '', '1', 'X' };
1103         struct trace_subsystem_dir *dir = filp->private_data;
1104         struct event_subsystem *system = dir->subsystem;
1105         struct trace_event_call *call;
1106         struct trace_event_file *file;
1107         struct trace_array *tr = dir->tr;
1108         char buf[2];
1109         int set = 0;
1110         int ret;
1111 
1112         mutex_lock(&event_mutex);
1113         list_for_each_entry(file, &tr->events, list) {
1114                 call = file->event_call;
1115                 if (!trace_event_name(call) || !call->class || !call->class->reg)
1116                         continue;
1117 
1118                 if (system && strcmp(call->class->system, system->name) != 0)
1119                         continue;
1120 
1121                 /*
1122                  * We need to find out if all the events are set
1123                  * or if all events or cleared, or if we have
1124                  * a mixture.
1125                  */
1126                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1127 
1128                 /*
1129                  * If we have a mixture, no need to look further.
1130                  */
1131                 if (set == 3)
1132                         break;
1133         }
1134         mutex_unlock(&event_mutex);
1135 
1136         buf[0] = set_to_char[set];
1137         buf[1] = '\n';
1138 
1139         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1140 
1141         return ret;
1142 }
1143 
1144 static ssize_t
1145 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1146                     loff_t *ppos)
1147 {
1148         struct trace_subsystem_dir *dir = filp->private_data;
1149         struct event_subsystem *system = dir->subsystem;
1150         const char *name = NULL;
1151         unsigned long val;
1152         ssize_t ret;
1153 
1154         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1155         if (ret)
1156                 return ret;
1157 
1158         ret = tracing_update_buffers();
1159         if (ret < 0)
1160                 return ret;
1161 
1162         if (val != 0 && val != 1)
1163                 return -EINVAL;
1164 
1165         /*
1166          * Opening of "enable" adds a ref count to system,
1167          * so the name is safe to use.
1168          */
1169         if (system)
1170                 name = system->name;
1171 
1172         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1173         if (ret)
1174                 goto out;
1175 
1176         ret = cnt;
1177 
1178 out:
1179         *ppos += cnt;
1180 
1181         return ret;
1182 }
1183 
1184 enum {
1185         FORMAT_HEADER           = 1,
1186         FORMAT_FIELD_SEPERATOR  = 2,
1187         FORMAT_PRINTFMT         = 3,
1188 };
1189 
1190 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1191 {
1192         struct trace_event_call *call = event_file_data(m->private);
1193         struct list_head *common_head = &ftrace_common_fields;
1194         struct list_head *head = trace_get_fields(call);
1195         struct list_head *node = v;
1196 
1197         (*pos)++;
1198 
1199         switch ((unsigned long)v) {
1200         case FORMAT_HEADER:
1201                 node = common_head;
1202                 break;
1203 
1204         case FORMAT_FIELD_SEPERATOR:
1205                 node = head;
1206                 break;
1207 
1208         case FORMAT_PRINTFMT:
1209                 /* all done */
1210                 return NULL;
1211         }
1212 
1213         node = node->prev;
1214         if (node == common_head)
1215                 return (void *)FORMAT_FIELD_SEPERATOR;
1216         else if (node == head)
1217                 return (void *)FORMAT_PRINTFMT;
1218         else
1219                 return node;
1220 }
1221 
1222 static int f_show(struct seq_file *m, void *v)
1223 {
1224         struct trace_event_call *call = event_file_data(m->private);
1225         struct ftrace_event_field *field;
1226         const char *array_descriptor;
1227 
1228         switch ((unsigned long)v) {
1229         case FORMAT_HEADER:
1230                 seq_printf(m, "name: %s\n", trace_event_name(call));
1231                 seq_printf(m, "ID: %d\n", call->event.type);
1232                 seq_puts(m, "format:\n");
1233                 return 0;
1234 
1235         case FORMAT_FIELD_SEPERATOR:
1236                 seq_putc(m, '\n');
1237                 return 0;
1238 
1239         case FORMAT_PRINTFMT:
1240                 seq_printf(m, "\nprint fmt: %s\n",
1241                            call->print_fmt);
1242                 return 0;
1243         }
1244 
1245         field = list_entry(v, struct ftrace_event_field, link);
1246         /*
1247          * Smartly shows the array type(except dynamic array).
1248          * Normal:
1249          *      field:TYPE VAR
1250          * If TYPE := TYPE[LEN], it is shown:
1251          *      field:TYPE VAR[LEN]
1252          */
1253         array_descriptor = strchr(field->type, '[');
1254 
1255         if (!strncmp(field->type, "__data_loc", 10))
1256                 array_descriptor = NULL;
1257 
1258         if (!array_descriptor)
1259                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1260                            field->type, field->name, field->offset,
1261                            field->size, !!field->is_signed);
1262         else
1263                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1264                            (int)(array_descriptor - field->type),
1265                            field->type, field->name,
1266                            array_descriptor, field->offset,
1267                            field->size, !!field->is_signed);
1268 
1269         return 0;
1270 }
1271 
1272 static void *f_start(struct seq_file *m, loff_t *pos)
1273 {
1274         void *p = (void *)FORMAT_HEADER;
1275         loff_t l = 0;
1276 
1277         /* ->stop() is called even if ->start() fails */
1278         mutex_lock(&event_mutex);
1279         if (!event_file_data(m->private))
1280                 return ERR_PTR(-ENODEV);
1281 
1282         while (l < *pos && p)
1283                 p = f_next(m, p, &l);
1284 
1285         return p;
1286 }
1287 
1288 static void f_stop(struct seq_file *m, void *p)
1289 {
1290         mutex_unlock(&event_mutex);
1291 }
1292 
1293 static const struct seq_operations trace_format_seq_ops = {
1294         .start          = f_start,
1295         .next           = f_next,
1296         .stop           = f_stop,
1297         .show           = f_show,
1298 };
1299 
1300 static int trace_format_open(struct inode *inode, struct file *file)
1301 {
1302         struct seq_file *m;
1303         int ret;
1304 
1305         ret = seq_open(file, &trace_format_seq_ops);
1306         if (ret < 0)
1307                 return ret;
1308 
1309         m = file->private_data;
1310         m->private = file;
1311 
1312         return 0;
1313 }
1314 
1315 static ssize_t
1316 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1317 {
1318         int id = (long)event_file_data(filp);
1319         char buf[32];
1320         int len;
1321 
1322         if (*ppos)
1323                 return 0;
1324 
1325         if (unlikely(!id))
1326                 return -ENODEV;
1327 
1328         len = sprintf(buf, "%d\n", id);
1329 
1330         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1331 }
1332 
1333 static ssize_t
1334 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1335                   loff_t *ppos)
1336 {
1337         struct trace_event_file *file;
1338         struct trace_seq *s;
1339         int r = -ENODEV;
1340 
1341         if (*ppos)
1342                 return 0;
1343 
1344         s = kmalloc(sizeof(*s), GFP_KERNEL);
1345 
1346         if (!s)
1347                 return -ENOMEM;
1348 
1349         trace_seq_init(s);
1350 
1351         mutex_lock(&event_mutex);
1352         file = event_file_data(filp);
1353         if (file)
1354                 print_event_filter(file, s);
1355         mutex_unlock(&event_mutex);
1356 
1357         if (file)
1358                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1359                                             s->buffer, trace_seq_used(s));
1360 
1361         kfree(s);
1362 
1363         return r;
1364 }
1365 
1366 static ssize_t
1367 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1368                    loff_t *ppos)
1369 {
1370         struct trace_event_file *file;
1371         char *buf;
1372         int err = -ENODEV;
1373 
1374         if (cnt >= PAGE_SIZE)
1375                 return -EINVAL;
1376 
1377         buf = memdup_user_nul(ubuf, cnt);
1378         if (IS_ERR(buf))
1379                 return PTR_ERR(buf);
1380 
1381         mutex_lock(&event_mutex);
1382         file = event_file_data(filp);
1383         if (file)
1384                 err = apply_event_filter(file, buf);
1385         mutex_unlock(&event_mutex);
1386 
1387         kfree(buf);
1388         if (err < 0)
1389                 return err;
1390 
1391         *ppos += cnt;
1392 
1393         return cnt;
1394 }
1395 
1396 static LIST_HEAD(event_subsystems);
1397 
1398 static int subsystem_open(struct inode *inode, struct file *filp)
1399 {
1400         struct event_subsystem *system = NULL;
1401         struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1402         struct trace_array *tr;
1403         int ret;
1404 
1405         if (tracing_is_disabled())
1406                 return -ENODEV;
1407 
1408         /* Make sure the system still exists */
1409         mutex_lock(&trace_types_lock);
1410         mutex_lock(&event_mutex);
1411         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1412                 list_for_each_entry(dir, &tr->systems, list) {
1413                         if (dir == inode->i_private) {
1414                                 /* Don't open systems with no events */
1415                                 if (dir->nr_events) {
1416                                         __get_system_dir(dir);
1417                                         system = dir->subsystem;
1418                                 }
1419                                 goto exit_loop;
1420                         }
1421                 }
1422         }
1423  exit_loop:
1424         mutex_unlock(&event_mutex);
1425         mutex_unlock(&trace_types_lock);
1426 
1427         if (!system)
1428                 return -ENODEV;
1429 
1430         /* Some versions of gcc think dir can be uninitialized here */
1431         WARN_ON(!dir);
1432 
1433         /* Still need to increment the ref count of the system */
1434         if (trace_array_get(tr) < 0) {
1435                 put_system(dir);
1436                 return -ENODEV;
1437         }
1438 
1439         ret = tracing_open_generic(inode, filp);
1440         if (ret < 0) {
1441                 trace_array_put(tr);
1442                 put_system(dir);
1443         }
1444 
1445         return ret;
1446 }
1447 
1448 static int system_tr_open(struct inode *inode, struct file *filp)
1449 {
1450         struct trace_subsystem_dir *dir;
1451         struct trace_array *tr = inode->i_private;
1452         int ret;
1453 
1454         if (tracing_is_disabled())
1455                 return -ENODEV;
1456 
1457         if (trace_array_get(tr) < 0)
1458                 return -ENODEV;
1459 
1460         /* Make a temporary dir that has no system but points to tr */
1461         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1462         if (!dir) {
1463                 trace_array_put(tr);
1464                 return -ENOMEM;
1465         }
1466 
1467         dir->tr = tr;
1468 
1469         ret = tracing_open_generic(inode, filp);
1470         if (ret < 0) {
1471                 trace_array_put(tr);
1472                 kfree(dir);
1473                 return ret;
1474         }
1475 
1476         filp->private_data = dir;
1477 
1478         return 0;
1479 }
1480 
1481 static int subsystem_release(struct inode *inode, struct file *file)
1482 {
1483         struct trace_subsystem_dir *dir = file->private_data;
1484 
1485         trace_array_put(dir->tr);
1486 
1487         /*
1488          * If dir->subsystem is NULL, then this is a temporary
1489          * descriptor that was made for a trace_array to enable
1490          * all subsystems.
1491          */
1492         if (dir->subsystem)
1493                 put_system(dir);
1494         else
1495                 kfree(dir);
1496 
1497         return 0;
1498 }
1499 
1500 static ssize_t
1501 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1502                       loff_t *ppos)
1503 {
1504         struct trace_subsystem_dir *dir = filp->private_data;
1505         struct event_subsystem *system = dir->subsystem;
1506         struct trace_seq *s;
1507         int r;
1508 
1509         if (*ppos)
1510                 return 0;
1511 
1512         s = kmalloc(sizeof(*s), GFP_KERNEL);
1513         if (!s)
1514                 return -ENOMEM;
1515 
1516         trace_seq_init(s);
1517 
1518         print_subsystem_event_filter(system, s);
1519         r = simple_read_from_buffer(ubuf, cnt, ppos,
1520                                     s->buffer, trace_seq_used(s));
1521 
1522         kfree(s);
1523 
1524         return r;
1525 }
1526 
1527 static ssize_t
1528 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1529                        loff_t *ppos)
1530 {
1531         struct trace_subsystem_dir *dir = filp->private_data;
1532         char *buf;
1533         int err;
1534 
1535         if (cnt >= PAGE_SIZE)
1536                 return -EINVAL;
1537 
1538         buf = memdup_user_nul(ubuf, cnt);
1539         if (IS_ERR(buf))
1540                 return PTR_ERR(buf);
1541 
1542         err = apply_subsystem_event_filter(dir, buf);
1543         kfree(buf);
1544         if (err < 0)
1545                 return err;
1546 
1547         *ppos += cnt;
1548 
1549         return cnt;
1550 }
1551 
1552 static ssize_t
1553 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1554 {
1555         int (*func)(struct trace_seq *s) = filp->private_data;
1556         struct trace_seq *s;
1557         int r;
1558 
1559         if (*ppos)
1560                 return 0;
1561 
1562         s = kmalloc(sizeof(*s), GFP_KERNEL);
1563         if (!s)
1564                 return -ENOMEM;
1565 
1566         trace_seq_init(s);
1567 
1568         func(s);
1569         r = simple_read_from_buffer(ubuf, cnt, ppos,
1570                                     s->buffer, trace_seq_used(s));
1571 
1572         kfree(s);
1573 
1574         return r;
1575 }
1576 
1577 static void ignore_task_cpu(void *data)
1578 {
1579         struct trace_array *tr = data;
1580         struct trace_pid_list *pid_list;
1581 
1582         /*
1583          * This function is called by on_each_cpu() while the
1584          * event_mutex is held.
1585          */
1586         pid_list = rcu_dereference_protected(tr->filtered_pids,
1587                                              mutex_is_locked(&event_mutex));
1588 
1589         this_cpu_write(tr->trace_buffer.data->ignore_pid,
1590                        trace_ignore_this_task(pid_list, current));
1591 }
1592 
1593 static ssize_t
1594 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1595                        size_t cnt, loff_t *ppos)
1596 {
1597         struct seq_file *m = filp->private_data;
1598         struct trace_array *tr = m->private;
1599         struct trace_pid_list *filtered_pids = NULL;
1600         struct trace_pid_list *pid_list;
1601         struct trace_event_file *file;
1602         ssize_t ret;
1603 
1604         if (!cnt)
1605                 return 0;
1606 
1607         ret = tracing_update_buffers();
1608         if (ret < 0)
1609                 return ret;
1610 
1611         mutex_lock(&event_mutex);
1612 
1613         filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1614                                              lockdep_is_held(&event_mutex));
1615 
1616         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1617         if (ret < 0)
1618                 goto out;
1619 
1620         rcu_assign_pointer(tr->filtered_pids, pid_list);
1621 
1622         list_for_each_entry(file, &tr->events, list) {
1623                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1624         }
1625 
1626         if (filtered_pids) {
1627                 synchronize_sched();
1628                 trace_free_pid_list(filtered_pids);
1629         } else if (pid_list) {
1630                 /*
1631                  * Register a probe that is called before all other probes
1632                  * to set ignore_pid if next or prev do not match.
1633                  * Register a probe this is called after all other probes
1634                  * to only keep ignore_pid set if next pid matches.
1635                  */
1636                 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1637                                                  tr, INT_MAX);
1638                 register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1639                                                  tr, 0);
1640 
1641                 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1642                                                  tr, INT_MAX);
1643                 register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1644                                                  tr, 0);
1645 
1646                 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1647                                                      tr, INT_MAX);
1648                 register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1649                                                      tr, 0);
1650 
1651                 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1652                                                  tr, INT_MAX);
1653                 register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1654                                                  tr, 0);
1655         }
1656 
1657         /*
1658          * Ignoring of pids is done at task switch. But we have to
1659          * check for those tasks that are currently running.
1660          * Always do this in case a pid was appended or removed.
1661          */
1662         on_each_cpu(ignore_task_cpu, tr, 1);
1663 
1664  out:
1665         mutex_unlock(&event_mutex);
1666 
1667         if (ret > 0)
1668                 *ppos += ret;
1669 
1670         return ret;
1671 }
1672 
1673 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1674 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1675 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
1676 static int ftrace_event_release(struct inode *inode, struct file *file);
1677 
1678 static const struct seq_operations show_event_seq_ops = {
1679         .start = t_start,
1680         .next = t_next,
1681         .show = t_show,
1682         .stop = t_stop,
1683 };
1684 
1685 static const struct seq_operations show_set_event_seq_ops = {
1686         .start = s_start,
1687         .next = s_next,
1688         .show = t_show,
1689         .stop = t_stop,
1690 };
1691 
1692 static const struct seq_operations show_set_pid_seq_ops = {
1693         .start = p_start,
1694         .next = p_next,
1695         .show = trace_pid_show,
1696         .stop = p_stop,
1697 };
1698 
1699 static const struct file_operations ftrace_avail_fops = {
1700         .open = ftrace_event_avail_open,
1701         .read = seq_read,
1702         .llseek = seq_lseek,
1703         .release = seq_release,
1704 };
1705 
1706 static const struct file_operations ftrace_set_event_fops = {
1707         .open = ftrace_event_set_open,
1708         .read = seq_read,
1709         .write = ftrace_event_write,
1710         .llseek = seq_lseek,
1711         .release = ftrace_event_release,
1712 };
1713 
1714 static const struct file_operations ftrace_set_event_pid_fops = {
1715         .open = ftrace_event_set_pid_open,
1716         .read = seq_read,
1717         .write = ftrace_event_pid_write,
1718         .llseek = seq_lseek,
1719         .release = ftrace_event_release,
1720 };
1721 
1722 static const struct file_operations ftrace_enable_fops = {
1723         .open = tracing_open_generic,
1724         .read = event_enable_read,
1725         .write = event_enable_write,
1726         .llseek = default_llseek,
1727 };
1728 
1729 static const struct file_operations ftrace_event_format_fops = {
1730         .open = trace_format_open,
1731         .read = seq_read,
1732         .llseek = seq_lseek,
1733         .release = seq_release,
1734 };
1735 
1736 static const struct file_operations ftrace_event_id_fops = {
1737         .read = event_id_read,
1738         .llseek = default_llseek,
1739 };
1740 
1741 static const struct file_operations ftrace_event_filter_fops = {
1742         .open = tracing_open_generic,
1743         .read = event_filter_read,
1744         .write = event_filter_write,
1745         .llseek = default_llseek,
1746 };
1747 
1748 static const struct file_operations ftrace_subsystem_filter_fops = {
1749         .open = subsystem_open,
1750         .read = subsystem_filter_read,
1751         .write = subsystem_filter_write,
1752         .llseek = default_llseek,
1753         .release = subsystem_release,
1754 };
1755 
1756 static const struct file_operations ftrace_system_enable_fops = {
1757         .open = subsystem_open,
1758         .read = system_enable_read,
1759         .write = system_enable_write,
1760         .llseek = default_llseek,
1761         .release = subsystem_release,
1762 };
1763 
1764 static const struct file_operations ftrace_tr_enable_fops = {
1765         .open = system_tr_open,
1766         .read = system_enable_read,
1767         .write = system_enable_write,
1768         .llseek = default_llseek,
1769         .release = subsystem_release,
1770 };
1771 
1772 static const struct file_operations ftrace_show_header_fops = {
1773         .open = tracing_open_generic,
1774         .read = show_header,
1775         .llseek = default_llseek,
1776 };
1777 
1778 static int
1779 ftrace_event_open(struct inode *inode, struct file *file,
1780                   const struct seq_operations *seq_ops)
1781 {
1782         struct seq_file *m;
1783         int ret;
1784 
1785         ret = seq_open(file, seq_ops);
1786         if (ret < 0)
1787                 return ret;
1788         m = file->private_data;
1789         /* copy tr over to seq ops */
1790         m->private = inode->i_private;
1791 
1792         return ret;
1793 }
1794 
1795 static int ftrace_event_release(struct inode *inode, struct file *file)
1796 {
1797         struct trace_array *tr = inode->i_private;
1798 
1799         trace_array_put(tr);
1800 
1801         return seq_release(inode, file);
1802 }
1803 
1804 static int
1805 ftrace_event_avail_open(struct inode *inode, struct file *file)
1806 {
1807         const struct seq_operations *seq_ops = &show_event_seq_ops;
1808 
1809         return ftrace_event_open(inode, file, seq_ops);
1810 }
1811 
1812 static int
1813 ftrace_event_set_open(struct inode *inode, struct file *file)
1814 {
1815         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1816         struct trace_array *tr = inode->i_private;
1817         int ret;
1818 
1819         if (trace_array_get(tr) < 0)
1820                 return -ENODEV;
1821 
1822         if ((file->f_mode & FMODE_WRITE) &&
1823             (file->f_flags & O_TRUNC))
1824                 ftrace_clear_events(tr);
1825 
1826         ret = ftrace_event_open(inode, file, seq_ops);
1827         if (ret < 0)
1828                 trace_array_put(tr);
1829         return ret;
1830 }
1831 
1832 static int
1833 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
1834 {
1835         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
1836         struct trace_array *tr = inode->i_private;
1837         int ret;
1838 
1839         if (trace_array_get(tr) < 0)
1840                 return -ENODEV;
1841 
1842         if ((file->f_mode & FMODE_WRITE) &&
1843             (file->f_flags & O_TRUNC))
1844                 ftrace_clear_event_pids(tr);
1845 
1846         ret = ftrace_event_open(inode, file, seq_ops);
1847         if (ret < 0)
1848                 trace_array_put(tr);
1849         return ret;
1850 }
1851 
1852 static struct event_subsystem *
1853 create_new_subsystem(const char *name)
1854 {
1855         struct event_subsystem *system;
1856 
1857         /* need to create new entry */
1858         system = kmalloc(sizeof(*system), GFP_KERNEL);
1859         if (!system)
1860                 return NULL;
1861 
1862         system->ref_count = 1;
1863 
1864         /* Only allocate if dynamic (kprobes and modules) */
1865         system->name = kstrdup_const(name, GFP_KERNEL);
1866         if (!system->name)
1867                 goto out_free;
1868 
1869         system->filter = NULL;
1870 
1871         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1872         if (!system->filter)
1873                 goto out_free;
1874 
1875         list_add(&system->list, &event_subsystems);
1876 
1877         return system;
1878 
1879  out_free:
1880         kfree_const(system->name);
1881         kfree(system);
1882         return NULL;
1883 }
1884 
1885 static struct dentry *
1886 event_subsystem_dir(struct trace_array *tr, const char *name,
1887                     struct trace_event_file *file, struct dentry *parent)
1888 {
1889         struct trace_subsystem_dir *dir;
1890         struct event_subsystem *system;
1891         struct dentry *entry;
1892 
1893         /* First see if we did not already create this dir */
1894         list_for_each_entry(dir, &tr->systems, list) {
1895                 system = dir->subsystem;
1896                 if (strcmp(system->name, name) == 0) {
1897                         dir->nr_events++;
1898                         file->system = dir;
1899                         return dir->entry;
1900                 }
1901         }
1902 
1903         /* Now see if the system itself exists. */
1904         list_for_each_entry(system, &event_subsystems, list) {
1905                 if (strcmp(system->name, name) == 0)
1906                         break;
1907         }
1908         /* Reset system variable when not found */
1909         if (&system->list == &event_subsystems)
1910                 system = NULL;
1911 
1912         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
1913         if (!dir)
1914                 goto out_fail;
1915 
1916         if (!system) {
1917                 system = create_new_subsystem(name);
1918                 if (!system)
1919                         goto out_free;
1920         } else
1921                 __get_system(system);
1922 
1923         dir->entry = tracefs_create_dir(name, parent);
1924         if (!dir->entry) {
1925                 pr_warn("Failed to create system directory %s\n", name);
1926                 __put_system(system);
1927                 goto out_free;
1928         }
1929 
1930         dir->tr = tr;
1931         dir->ref_count = 1;
1932         dir->nr_events = 1;
1933         dir->subsystem = system;
1934         file->system = dir;
1935 
1936         entry = tracefs_create_file("filter", 0644, dir->entry, dir,
1937                                     &ftrace_subsystem_filter_fops);
1938         if (!entry) {
1939                 kfree(system->filter);
1940                 system->filter = NULL;
1941                 pr_warn("Could not create tracefs '%s/filter' entry\n", name);
1942         }
1943 
1944         trace_create_file("enable", 0644, dir->entry, dir,
1945                           &ftrace_system_enable_fops);
1946 
1947         list_add(&dir->list, &tr->systems);
1948 
1949         return dir->entry;
1950 
1951  out_free:
1952         kfree(dir);
1953  out_fail:
1954         /* Only print this message if failed on memory allocation */
1955         if (!dir || !system)
1956                 pr_warn("No memory to create event subsystem %s\n", name);
1957         return NULL;
1958 }
1959 
1960 static int
1961 event_create_dir(struct dentry *parent, struct trace_event_file *file)
1962 {
1963         struct trace_event_call *call = file->event_call;
1964         struct trace_array *tr = file->tr;
1965         struct list_head *head;
1966         struct dentry *d_events;
1967         const char *name;
1968         int ret;
1969 
1970         /*
1971          * If the trace point header did not define TRACE_SYSTEM
1972          * then the system would be called "TRACE_SYSTEM".
1973          */
1974         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
1975                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
1976                 if (!d_events)
1977                         return -ENOMEM;
1978         } else
1979                 d_events = parent;
1980 
1981         name = trace_event_name(call);
1982         file->dir = tracefs_create_dir(name, d_events);
1983         if (!file->dir) {
1984                 pr_warn("Could not create tracefs '%s' directory\n", name);
1985                 return -1;
1986         }
1987 
1988         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1989                 trace_create_file("enable", 0644, file->dir, file,
1990                                   &ftrace_enable_fops);
1991 
1992 #ifdef CONFIG_PERF_EVENTS
1993         if (call->event.type && call->class->reg)
1994                 trace_create_file("id", 0444, file->dir,
1995                                   (void *)(long)call->event.type,
1996                                   &ftrace_event_id_fops);
1997 #endif
1998 
1999         /*
2000          * Other events may have the same class. Only update
2001          * the fields if they are not already defined.
2002          */
2003         head = trace_get_fields(call);
2004         if (list_empty(head)) {
2005                 ret = call->class->define_fields(call);
2006                 if (ret < 0) {
2007                         pr_warn("Could not initialize trace point events/%s\n",
2008                                 name);
2009                         return -1;
2010                 }
2011         }
2012         trace_create_file("filter", 0644, file->dir, file,
2013                           &ftrace_event_filter_fops);
2014 
2015         /*
2016          * Only event directories that can be enabled should have
2017          * triggers.
2018          */
2019         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2020                 trace_create_file("trigger", 0644, file->dir, file,
2021                                   &event_trigger_fops);
2022 
2023 #ifdef CONFIG_HIST_TRIGGERS
2024         trace_create_file("hist", 0444, file->dir, file,
2025                           &event_hist_fops);
2026 #endif
2027         trace_create_file("format", 0444, file->dir, call,
2028                           &ftrace_event_format_fops);
2029 
2030         return 0;
2031 }
2032 
2033 static void remove_event_from_tracers(struct trace_event_call *call)
2034 {
2035         struct trace_event_file *file;
2036         struct trace_array *tr;
2037 
2038         do_for_each_event_file_safe(tr, file) {
2039                 if (file->event_call != call)
2040                         continue;
2041 
2042                 remove_event_file_dir(file);
2043                 /*
2044                  * The do_for_each_event_file_safe() is
2045                  * a double loop. After finding the call for this
2046                  * trace_array, we use break to jump to the next
2047                  * trace_array.
2048                  */
2049                 break;
2050         } while_for_each_event_file();
2051 }
2052 
2053 static void event_remove(struct trace_event_call *call)
2054 {
2055         struct trace_array *tr;
2056         struct trace_event_file *file;
2057 
2058         do_for_each_event_file(tr, file) {
2059                 if (file->event_call != call)
2060                         continue;
2061 
2062                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2063                         tr->clear_trace = true;
2064 
2065                 ftrace_event_enable_disable(file, 0);
2066                 /*
2067                  * The do_for_each_event_file() is
2068                  * a double loop. After finding the call for this
2069                  * trace_array, we use break to jump to the next
2070                  * trace_array.
2071                  */
2072                 break;
2073         } while_for_each_event_file();
2074 
2075         if (call->event.funcs)
2076                 __unregister_trace_event(&call->event);
2077         remove_event_from_tracers(call);
2078         list_del(&call->list);
2079 }
2080 
2081 static int event_init(struct trace_event_call *call)
2082 {
2083         int ret = 0;
2084         const char *name;
2085 
2086         name = trace_event_name(call);
2087         if (WARN_ON(!name))
2088                 return -EINVAL;
2089 
2090         if (call->class->raw_init) {
2091                 ret = call->class->raw_init(call);
2092                 if (ret < 0 && ret != -ENOSYS)
2093                         pr_warn("Could not initialize trace events/%s\n", name);
2094         }
2095 
2096         return ret;
2097 }
2098 
2099 static int
2100 __register_event(struct trace_event_call *call, struct module *mod)
2101 {
2102         int ret;
2103 
2104         ret = event_init(call);
2105         if (ret < 0)
2106                 return ret;
2107 
2108         list_add(&call->list, &ftrace_events);
2109         call->mod = mod;
2110 
2111         return 0;
2112 }
2113 
2114 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2115 {
2116         int rlen;
2117         int elen;
2118 
2119         /* Find the length of the eval value as a string */
2120         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2121         /* Make sure there's enough room to replace the string with the value */
2122         if (len < elen)
2123                 return NULL;
2124 
2125         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2126 
2127         /* Get the rest of the string of ptr */
2128         rlen = strlen(ptr + len);
2129         memmove(ptr + elen, ptr + len, rlen);
2130         /* Make sure we end the new string */
2131         ptr[elen + rlen] = 0;
2132 
2133         return ptr + elen;
2134 }
2135 
2136 static void update_event_printk(struct trace_event_call *call,
2137                                 struct trace_eval_map *map)
2138 {
2139         char *ptr;
2140         int quote = 0;
2141         int len = strlen(map->eval_string);
2142 
2143         for (ptr = call->print_fmt; *ptr; ptr++) {
2144                 if (*ptr == '\\') {
2145                         ptr++;
2146                         /* paranoid */
2147                         if (!*ptr)
2148                                 break;
2149                         continue;
2150                 }
2151                 if (*ptr == '"') {
2152                         quote ^= 1;
2153                         continue;
2154                 }
2155                 if (quote)
2156                         continue;
2157                 if (isdigit(*ptr)) {
2158                         /* skip numbers */
2159                         do {
2160                                 ptr++;
2161                                 /* Check for alpha chars like ULL */
2162                         } while (isalnum(*ptr));
2163                         if (!*ptr)
2164                                 break;
2165                         /*
2166                          * A number must have some kind of delimiter after
2167                          * it, and we can ignore that too.
2168                          */
2169                         continue;
2170                 }
2171                 if (isalpha(*ptr) || *ptr == '_') {
2172                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2173                             !isalnum(ptr[len]) && ptr[len] != '_') {
2174                                 ptr = eval_replace(ptr, map, len);
2175                                 /* enum/sizeof string smaller than value */
2176                                 if (WARN_ON_ONCE(!ptr))
2177                                         return;
2178                                 /*
2179                                  * No need to decrement here, as eval_replace()
2180                                  * returns the pointer to the character passed
2181                                  * the eval, and two evals can not be placed
2182                                  * back to back without something in between.
2183                                  * We can skip that something in between.
2184                                  */
2185                                 continue;
2186                         }
2187                 skip_more:
2188                         do {
2189                                 ptr++;
2190                         } while (isalnum(*ptr) || *ptr == '_');
2191                         if (!*ptr)
2192                                 break;
2193                         /*
2194                          * If what comes after this variable is a '.' or
2195                          * '->' then we can continue to ignore that string.
2196                          */
2197                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2198                                 ptr += *ptr == '.' ? 1 : 2;
2199                                 if (!*ptr)
2200                                         break;
2201                                 goto skip_more;
2202                         }
2203                         /*
2204                          * Once again, we can skip the delimiter that came
2205                          * after the string.
2206                          */
2207                         continue;
2208                 }
2209         }
2210 }
2211 
2212 void trace_event_eval_update(struct trace_eval_map **map, int len)
2213 {
2214         struct trace_event_call *call, *p;
2215         const char *last_system = NULL;
2216         int last_i;
2217         int i;
2218 
2219         down_write(&trace_event_sem);
2220         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2221                 /* events are usually grouped together with systems */
2222                 if (!last_system || call->class->system != last_system) {
2223                         last_i = 0;
2224                         last_system = call->class->system;
2225                 }
2226 
2227                 for (i = last_i; i < len; i++) {
2228                         if (call->class->system == map[i]->system) {
2229                                 /* Save the first system if need be */
2230                                 if (!last_i)
2231                                         last_i = i;
2232                                 update_event_printk(call, map[i]);
2233                         }
2234                 }
2235         }
2236         up_write(&trace_event_sem);
2237 }
2238 
2239 static struct trace_event_file *
2240 trace_create_new_event(struct trace_event_call *call,
2241                        struct trace_array *tr)
2242 {
2243         struct trace_event_file *file;
2244 
2245         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2246         if (!file)
2247                 return NULL;
2248 
2249         file->event_call = call;
2250         file->tr = tr;
2251         atomic_set(&file->sm_ref, 0);
2252         atomic_set(&file->tm_ref, 0);
2253         INIT_LIST_HEAD(&file->triggers);
2254         list_add(&file->list, &tr->events);
2255 
2256         return file;
2257 }
2258 
2259 /* Add an event to a trace directory */
2260 static int
2261 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2262 {
2263         struct trace_event_file *file;
2264 
2265         file = trace_create_new_event(call, tr);
2266         if (!file)
2267                 return -ENOMEM;
2268 
2269         return event_create_dir(tr->event_dir, file);
2270 }
2271 
2272 /*
2273  * Just create a decriptor for early init. A descriptor is required
2274  * for enabling events at boot. We want to enable events before
2275  * the filesystem is initialized.
2276  */
2277 static __init int
2278 __trace_early_add_new_event(struct trace_event_call *call,
2279                             struct trace_array *tr)
2280 {
2281         struct trace_event_file *file;
2282 
2283         file = trace_create_new_event(call, tr);
2284         if (!file)
2285                 return -ENOMEM;
2286 
2287         return 0;
2288 }
2289 
2290 struct ftrace_module_file_ops;
2291 static void __add_event_to_tracers(struct trace_event_call *call);
2292 
2293 /* Add an additional event_call dynamically */
2294 int trace_add_event_call(struct trace_event_call *call)
2295 {
2296         int ret;
2297         mutex_lock(&trace_types_lock);
2298         mutex_lock(&event_mutex);
2299 
2300         ret = __register_event(call, NULL);
2301         if (ret >= 0)
2302                 __add_event_to_tracers(call);
2303 
2304         mutex_unlock(&event_mutex);
2305         mutex_unlock(&trace_types_lock);
2306         return ret;
2307 }
2308 
2309 /*
2310  * Must be called under locking of trace_types_lock, event_mutex and
2311  * trace_event_sem.
2312  */
2313 static void __trace_remove_event_call(struct trace_event_call *call)
2314 {
2315         event_remove(call);
2316         trace_destroy_fields(call);
2317         free_event_filter(call->filter);
2318         call->filter = NULL;
2319 }
2320 
2321 static int probe_remove_event_call(struct trace_event_call *call)
2322 {
2323         struct trace_array *tr;
2324         struct trace_event_file *file;
2325 
2326 #ifdef CONFIG_PERF_EVENTS
2327         if (call->perf_refcount)
2328                 return -EBUSY;
2329 #endif
2330         do_for_each_event_file(tr, file) {
2331                 if (file->event_call != call)
2332                         continue;
2333                 /*
2334                  * We can't rely on ftrace_event_enable_disable(enable => 0)
2335                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2336                  * TRACE_REG_UNREGISTER.
2337                  */
2338                 if (file->flags & EVENT_FILE_FL_ENABLED)
2339                         return -EBUSY;
2340                 /*
2341                  * The do_for_each_event_file_safe() is
2342                  * a double loop. After finding the call for this
2343                  * trace_array, we use break to jump to the next
2344                  * trace_array.
2345                  */
2346                 break;
2347         } while_for_each_event_file();
2348 
2349         __trace_remove_event_call(call);
2350 
2351         return 0;
2352 }
2353 
2354 /* Remove an event_call */
2355 int trace_remove_event_call(struct trace_event_call *call)
2356 {
2357         int ret;
2358 
2359         mutex_lock(&trace_types_lock);
2360         mutex_lock(&event_mutex);
2361         down_write(&trace_event_sem);
2362         ret = probe_remove_event_call(call);
2363         up_write(&trace_event_sem);
2364         mutex_unlock(&event_mutex);
2365         mutex_unlock(&trace_types_lock);
2366 
2367         return ret;
2368 }
2369 
2370 #define for_each_event(event, start, end)                       \
2371         for (event = start;                                     \
2372              (unsigned long)event < (unsigned long)end;         \
2373              event++)
2374 
2375 #ifdef CONFIG_MODULES
2376 
2377 static void trace_module_add_events(struct module *mod)
2378 {
2379         struct trace_event_call **call, **start, **end;
2380 
2381         if (!mod->num_trace_events)
2382                 return;
2383 
2384         /* Don't add infrastructure for mods without tracepoints */
2385         if (trace_module_has_bad_taint(mod)) {
2386                 pr_err("%s: module has bad taint, not creating trace events\n",
2387                        mod->name);
2388                 return;
2389         }
2390 
2391         start = mod->trace_events;
2392         end = mod->trace_events + mod->num_trace_events;
2393 
2394         for_each_event(call, start, end) {
2395                 __register_event(*call, mod);
2396                 __add_event_to_tracers(*call);
2397         }
2398 }
2399 
2400 static void trace_module_remove_events(struct module *mod)
2401 {
2402         struct trace_event_call *call, *p;
2403 
2404         down_write(&trace_event_sem);
2405         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2406                 if (call->mod == mod)
2407                         __trace_remove_event_call(call);
2408         }
2409         up_write(&trace_event_sem);
2410 
2411         /*
2412          * It is safest to reset the ring buffer if the module being unloaded
2413          * registered any events that were used. The only worry is if
2414          * a new module gets loaded, and takes on the same id as the events
2415          * of this module. When printing out the buffer, traced events left
2416          * over from this module may be passed to the new module events and
2417          * unexpected results may occur.
2418          */
2419         tracing_reset_all_online_cpus();
2420 }
2421 
2422 static int trace_module_notify(struct notifier_block *self,
2423                                unsigned long val, void *data)
2424 {
2425         struct module *mod = data;
2426 
2427         mutex_lock(&trace_types_lock);
2428         mutex_lock(&event_mutex);
2429         switch (val) {
2430         case MODULE_STATE_COMING:
2431                 trace_module_add_events(mod);
2432                 break;
2433         case MODULE_STATE_GOING:
2434                 trace_module_remove_events(mod);
2435                 break;
2436         }
2437         mutex_unlock(&event_mutex);
2438         mutex_unlock(&trace_types_lock);
2439 
2440         return 0;
2441 }
2442 
2443 static struct notifier_block trace_module_nb = {
2444         .notifier_call = trace_module_notify,
2445         .priority = 1, /* higher than trace.c module notify */
2446 };
2447 #endif /* CONFIG_MODULES */
2448 
2449 /* Create a new event directory structure for a trace directory. */
2450 static void
2451 __trace_add_event_dirs(struct trace_array *tr)
2452 {
2453         struct trace_event_call *call;
2454         int ret;
2455 
2456         list_for_each_entry(call, &ftrace_events, list) {
2457                 ret = __trace_add_new_event(call, tr);
2458                 if (ret < 0)
2459                         pr_warn("Could not create directory for event %s\n",
2460                                 trace_event_name(call));
2461         }
2462 }
2463 
2464 struct trace_event_file *
2465 find_event_file(struct trace_array *tr, const char *system,  const char *event)
2466 {
2467         struct trace_event_file *file;
2468         struct trace_event_call *call;
2469         const char *name;
2470 
2471         list_for_each_entry(file, &tr->events, list) {
2472 
2473                 call = file->event_call;
2474                 name = trace_event_name(call);
2475 
2476                 if (!name || !call->class || !call->class->reg)
2477                         continue;
2478 
2479                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2480                         continue;
2481 
2482                 if (strcmp(event, name) == 0 &&
2483                     strcmp(system, call->class->system) == 0)
2484                         return file;
2485         }
2486         return NULL;
2487 }
2488 
2489 #ifdef CONFIG_DYNAMIC_FTRACE
2490 
2491 /* Avoid typos */
2492 #define ENABLE_EVENT_STR        "enable_event"
2493 #define DISABLE_EVENT_STR       "disable_event"
2494 
2495 struct event_probe_data {
2496         struct trace_event_file *file;
2497         unsigned long                   count;
2498         int                             ref;
2499         bool                            enable;
2500 };
2501 
2502 static void update_event_probe(struct event_probe_data *data)
2503 {
2504         if (data->enable)
2505                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2506         else
2507                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2508 }
2509 
2510 static void
2511 event_enable_probe(unsigned long ip, unsigned long parent_ip,
2512                    struct trace_array *tr, struct ftrace_probe_ops *ops,
2513                    void *data)
2514 {
2515         struct ftrace_func_mapper *mapper = data;
2516         struct event_probe_data *edata;
2517         void **pdata;
2518 
2519         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2520         if (!pdata || !*pdata)
2521                 return;
2522 
2523         edata = *pdata;
2524         update_event_probe(edata);
2525 }
2526 
2527 static void
2528 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
2529                          struct trace_array *tr, struct ftrace_probe_ops *ops,
2530                          void *data)
2531 {
2532         struct ftrace_func_mapper *mapper = data;
2533         struct event_probe_data *edata;
2534         void **pdata;
2535 
2536         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2537         if (!pdata || !*pdata)
2538                 return;
2539 
2540         edata = *pdata;
2541 
2542         if (!edata->count)
2543                 return;
2544 
2545         /* Skip if the event is in a state we want to switch to */
2546         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
2547                 return;
2548 
2549         if (edata->count != -1)
2550                 (edata->count)--;
2551 
2552         update_event_probe(edata);
2553 }
2554 
2555 static int
2556 event_enable_print(struct seq_file *m, unsigned long ip,
2557                    struct ftrace_probe_ops *ops, void *data)
2558 {
2559         struct ftrace_func_mapper *mapper = data;
2560         struct event_probe_data *edata;
2561         void **pdata;
2562 
2563         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2564 
2565         if (WARN_ON_ONCE(!pdata || !*pdata))
2566                 return 0;
2567 
2568         edata = *pdata;
2569 
2570         seq_printf(m, "%ps:", (void *)ip);
2571 
2572         seq_printf(m, "%s:%s:%s",
2573                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2574                    edata->file->event_call->class->system,
2575                    trace_event_name(edata->file->event_call));
2576 
2577         if (edata->count == -1)
2578                 seq_puts(m, ":unlimited\n");
2579         else
2580                 seq_printf(m, ":count=%ld\n", edata->count);
2581 
2582         return 0;
2583 }
2584 
2585 static int
2586 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
2587                   unsigned long ip, void *init_data, void **data)
2588 {
2589         struct ftrace_func_mapper *mapper = *data;
2590         struct event_probe_data *edata = init_data;
2591         int ret;
2592 
2593         if (!mapper) {
2594                 mapper = allocate_ftrace_func_mapper();
2595                 if (!mapper)
2596                         return -ENODEV;
2597                 *data = mapper;
2598         }
2599 
2600         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
2601         if (ret < 0)
2602                 return ret;
2603 
2604         edata->ref++;
2605 
2606         return 0;
2607 }
2608 
2609 static int free_probe_data(void *data)
2610 {
2611         struct event_probe_data *edata = data;
2612 
2613         edata->ref--;
2614         if (!edata->ref) {
2615                 /* Remove the SOFT_MODE flag */
2616                 __ftrace_event_enable_disable(edata->file, 0, 1);
2617                 module_put(edata->file->event_call->mod);
2618                 kfree(edata);
2619         }
2620         return 0;
2621 }
2622 
2623 static void
2624 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
2625                   unsigned long ip, void *data)
2626 {
2627         struct ftrace_func_mapper *mapper = data;
2628         struct event_probe_data *edata;
2629 
2630         if (!ip) {
2631                 if (!mapper)
2632                         return;
2633                 free_ftrace_func_mapper(mapper, free_probe_data);
2634                 return;
2635         }
2636 
2637         edata = ftrace_func_mapper_remove_ip(mapper, ip);
2638 
2639         if (WARN_ON_ONCE(!edata))
2640                 return;
2641 
2642         if (WARN_ON_ONCE(edata->ref <= 0))
2643                 return;
2644 
2645         free_probe_data(edata);
2646 }
2647 
2648 static struct ftrace_probe_ops event_enable_probe_ops = {
2649         .func                   = event_enable_probe,
2650         .print                  = event_enable_print,
2651         .init                   = event_enable_init,
2652         .free                   = event_enable_free,
2653 };
2654 
2655 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2656         .func                   = event_enable_count_probe,
2657         .print                  = event_enable_print,
2658         .init                   = event_enable_init,
2659         .free                   = event_enable_free,
2660 };
2661 
2662 static struct ftrace_probe_ops event_disable_probe_ops = {
2663         .func                   = event_enable_probe,
2664         .print                  = event_enable_print,
2665         .init                   = event_enable_init,
2666         .free                   = event_enable_free,
2667 };
2668 
2669 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2670         .func                   = event_enable_count_probe,
2671         .print                  = event_enable_print,
2672         .init                   = event_enable_init,
2673         .free                   = event_enable_free,
2674 };
2675 
2676 static int
2677 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
2678                   char *glob, char *cmd, char *param, int enabled)
2679 {
2680         struct trace_event_file *file;
2681         struct ftrace_probe_ops *ops;
2682         struct event_probe_data *data;
2683         const char *system;
2684         const char *event;
2685         char *number;
2686         bool enable;
2687         int ret;
2688 
2689         if (!tr)
2690                 return -ENODEV;
2691 
2692         /* hash funcs only work with set_ftrace_filter */
2693         if (!enabled || !param)
2694                 return -EINVAL;
2695 
2696         system = strsep(&param, ":");
2697         if (!param)
2698                 return -EINVAL;
2699 
2700         event = strsep(&param, ":");
2701 
2702         mutex_lock(&event_mutex);
2703 
2704         ret = -EINVAL;
2705         file = find_event_file(tr, system, event);
2706         if (!file)
2707                 goto out;
2708 
2709         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
2710 
2711         if (enable)
2712                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
2713         else
2714                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
2715 
2716         if (glob[0] == '!') {
2717                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
2718                 goto out;
2719         }
2720 
2721         ret = -ENOMEM;
2722 
2723         data = kzalloc(sizeof(*data), GFP_KERNEL);
2724         if (!data)
2725                 goto out;
2726 
2727         data->enable = enable;
2728         data->count = -1;
2729         data->file = file;
2730 
2731         if (!param)
2732                 goto out_reg;
2733 
2734         number = strsep(&param, ":");
2735 
2736         ret = -EINVAL;
2737         if (!strlen(number))
2738                 goto out_free;
2739 
2740         /*
2741          * We use the callback data field (which is a pointer)
2742          * as our counter.
2743          */
2744         ret = kstrtoul(number, 0, &data->count);
2745         if (ret)
2746                 goto out_free;
2747 
2748  out_reg:
2749         /* Don't let event modules unload while probe registered */
2750         ret = try_module_get(file->event_call->mod);
2751         if (!ret) {
2752                 ret = -EBUSY;
2753                 goto out_free;
2754         }
2755 
2756         ret = __ftrace_event_enable_disable(file, 1, 1);
2757         if (ret < 0)
2758                 goto out_put;
2759 
2760         ret = register_ftrace_function_probe(glob, tr, ops, data);
2761         /*
2762          * The above returns on success the # of functions enabled,
2763          * but if it didn't find any functions it returns zero.
2764          * Consider no functions a failure too.
2765          */
2766         if (!ret) {
2767                 ret = -ENOENT;
2768                 goto out_disable;
2769         } else if (ret < 0)
2770                 goto out_disable;
2771         /* Just return zero, not the number of enabled functions */
2772         ret = 0;
2773  out:
2774         mutex_unlock(&event_mutex);
2775         return ret;
2776 
2777  out_disable:
2778         __ftrace_event_enable_disable(file, 0, 1);
2779  out_put:
2780         module_put(file->event_call->mod);
2781  out_free:
2782         kfree(data);
2783         goto out;
2784 }
2785 
2786 static struct ftrace_func_command event_enable_cmd = {
2787         .name                   = ENABLE_EVENT_STR,
2788         .func                   = event_enable_func,
2789 };
2790 
2791 static struct ftrace_func_command event_disable_cmd = {
2792         .name                   = DISABLE_EVENT_STR,
2793         .func                   = event_enable_func,
2794 };
2795 
2796 static __init int register_event_cmds(void)
2797 {
2798         int ret;
2799 
2800         ret = register_ftrace_command(&event_enable_cmd);
2801         if (WARN_ON(ret < 0))
2802                 return ret;
2803         ret = register_ftrace_command(&event_disable_cmd);
2804         if (WARN_ON(ret < 0))
2805                 unregister_ftrace_command(&event_enable_cmd);
2806         return ret;
2807 }
2808 #else
2809 static inline int register_event_cmds(void) { return 0; }
2810 #endif /* CONFIG_DYNAMIC_FTRACE */
2811 
2812 /*
2813  * The top level array has already had its trace_event_file
2814  * descriptors created in order to allow for early events to
2815  * be recorded. This function is called after the tracefs has been
2816  * initialized, and we now have to create the files associated
2817  * to the events.
2818  */
2819 static __init void
2820 __trace_early_add_event_dirs(struct trace_array *tr)
2821 {
2822         struct trace_event_file *file;
2823         int ret;
2824 
2825 
2826         list_for_each_entry(file, &tr->events, list) {
2827                 ret = event_create_dir(tr->event_dir, file);
2828                 if (ret < 0)
2829                         pr_warn("Could not create directory for event %s\n",
2830                                 trace_event_name(file->event_call));
2831         }
2832 }
2833 
2834 /*
2835  * For early boot up, the top trace array requires to have
2836  * a list of events that can be enabled. This must be done before
2837  * the filesystem is set up in order to allow events to be traced
2838  * early.
2839  */
2840 static __init void
2841 __trace_early_add_events(struct trace_array *tr)
2842 {
2843         struct trace_event_call *call;
2844         int ret;
2845 
2846         list_for_each_entry(call, &ftrace_events, list) {
2847                 /* Early boot up should not have any modules loaded */
2848                 if (WARN_ON_ONCE(call->mod))
2849                         continue;
2850 
2851                 ret = __trace_early_add_new_event(call, tr);
2852                 if (ret < 0)
2853                         pr_warn("Could not create early event %s\n",
2854                                 trace_event_name(call));
2855         }
2856 }
2857 
2858 /* Remove the event directory structure for a trace directory. */
2859 static void
2860 __trace_remove_event_dirs(struct trace_array *tr)
2861 {
2862         struct trace_event_file *file, *next;
2863 
2864         list_for_each_entry_safe(file, next, &tr->events, list)
2865                 remove_event_file_dir(file);
2866 }
2867 
2868 static void __add_event_to_tracers(struct trace_event_call *call)
2869 {
2870         struct trace_array *tr;
2871 
2872         list_for_each_entry(tr, &ftrace_trace_arrays, list)
2873                 __trace_add_new_event(call, tr);
2874 }
2875 
2876 extern struct trace_event_call *__start_ftrace_events[];
2877 extern struct trace_event_call *__stop_ftrace_events[];
2878 
2879 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
2880 
2881 static __init int setup_trace_event(char *str)
2882 {
2883         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
2884         ring_buffer_expanded = true;
2885         tracing_selftest_disabled = true;
2886 
2887         return 1;
2888 }
2889 __setup("trace_event=", setup_trace_event);
2890 
2891 /* Expects to have event_mutex held when called */
2892 static int
2893 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
2894 {
2895         struct dentry *d_events;
2896         struct dentry *entry;
2897 
2898         entry = tracefs_create_file("set_event", 0644, parent,
2899                                     tr, &ftrace_set_event_fops);
2900         if (!entry) {
2901                 pr_warn("Could not create tracefs 'set_event' entry\n");
2902                 return -ENOMEM;
2903         }
2904 
2905         d_events = tracefs_create_dir("events", parent);
2906         if (!d_events) {
2907                 pr_warn("Could not create tracefs 'events' directory\n");
2908                 return -ENOMEM;
2909         }
2910 
2911         entry = trace_create_file("enable", 0644, d_events,
2912                                   tr, &ftrace_tr_enable_fops);
2913         if (!entry) {
2914                 pr_warn("Could not create tracefs 'enable' entry\n");
2915                 return -ENOMEM;
2916         }
2917 
2918         /* There are not as crucial, just warn if they are not created */
2919 
2920         entry = tracefs_create_file("set_event_pid", 0644, parent,
2921                                     tr, &ftrace_set_event_pid_fops);
2922         if (!entry)
2923                 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
2924 
2925         /* ring buffer internal formats */
2926         entry = trace_create_file("header_page", 0444, d_events,
2927                                   ring_buffer_print_page_header,
2928                                   &ftrace_show_header_fops);
2929         if (!entry)
2930                 pr_warn("Could not create tracefs 'header_page' entry\n");
2931 
2932         entry = trace_create_file("header_event", 0444, d_events,
2933                                   ring_buffer_print_entry_header,
2934                                   &ftrace_show_header_fops);
2935         if (!entry)
2936                 pr_warn("Could not create tracefs 'header_event' entry\n");
2937 
2938         tr->event_dir = d_events;
2939 
2940         return 0;
2941 }
2942 
2943 /**
2944  * event_trace_add_tracer - add a instance of a trace_array to events
2945  * @parent: The parent dentry to place the files/directories for events in
2946  * @tr: The trace array associated with these events
2947  *
2948  * When a new instance is created, it needs to set up its events
2949  * directory, as well as other files associated with events. It also
2950  * creates the event hierachry in the @parent/events directory.
2951  *
2952  * Returns 0 on success.
2953  */
2954 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
2955 {
2956         int ret;
2957 
2958         mutex_lock(&event_mutex);
2959 
2960         ret = create_event_toplevel_files(parent, tr);
2961         if (ret)
2962                 goto out_unlock;
2963 
2964         down_write(&trace_event_sem);
2965         __trace_add_event_dirs(tr);
2966         up_write(&trace_event_sem);
2967 
2968  out_unlock:
2969         mutex_unlock(&event_mutex);
2970 
2971         return ret;
2972 }
2973 
2974 /*
2975  * The top trace array already had its file descriptors created.
2976  * Now the files themselves need to be created.
2977  */
2978 static __init int
2979 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
2980 {
2981         int ret;
2982 
2983         mutex_lock(&event_mutex);
2984 
2985         ret = create_event_toplevel_files(parent, tr);
2986         if (ret)
2987                 goto out_unlock;
2988 
2989         down_write(&trace_event_sem);
2990         __trace_early_add_event_dirs(tr);
2991         up_write(&trace_event_sem);
2992 
2993  out_unlock:
2994         mutex_unlock(&event_mutex);
2995 
2996         return ret;
2997 }
2998 
2999 int event_trace_del_tracer(struct trace_array *tr)
3000 {
3001         mutex_lock(&event_mutex);
3002 
3003         /* Disable any event triggers and associated soft-disabled events */
3004         clear_event_triggers(tr);
3005 
3006         /* Clear the pid list */
3007         __ftrace_clear_event_pids(tr);
3008 
3009         /* Disable any running events */
3010         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3011 
3012         /* Access to events are within rcu_read_lock_sched() */
3013         synchronize_sched();
3014 
3015         down_write(&trace_event_sem);
3016         __trace_remove_event_dirs(tr);
3017         tracefs_remove_recursive(tr->event_dir);
3018         up_write(&trace_event_sem);
3019 
3020         tr->event_dir = NULL;
3021 
3022         mutex_unlock(&event_mutex);
3023 
3024         return 0;
3025 }
3026 
3027 static __init int event_trace_memsetup(void)
3028 {
3029         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3030         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3031         return 0;
3032 }
3033 
3034 static __init void
3035 early_enable_events(struct trace_array *tr, bool disable_first)
3036 {
3037         char *buf = bootup_event_buf;
3038         char *token;
3039         int ret;
3040 
3041         while (true) {
3042                 token = strsep(&buf, ",");
3043 
3044                 if (!token)
3045                         break;
3046 
3047                 if (*token) {
3048                         /* Restarting syscalls requires that we stop them first */
3049                         if (disable_first)
3050                                 ftrace_set_clr_event(tr, token, 0);
3051 
3052                         ret = ftrace_set_clr_event(tr, token, 1);
3053                         if (ret)
3054                                 pr_warn("Failed to enable trace event: %s\n", token);
3055                 }
3056 
3057                 /* Put back the comma to allow this to be called again */
3058                 if (buf)
3059                         *(buf - 1) = ',';
3060         }
3061 }
3062 
3063 static __init int event_trace_enable(void)
3064 {
3065         struct trace_array *tr = top_trace_array();
3066         struct trace_event_call **iter, *call;
3067         int ret;
3068 
3069         if (!tr)
3070                 return -ENODEV;
3071 
3072         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3073 
3074                 call = *iter;
3075                 ret = event_init(call);
3076                 if (!ret)
3077                         list_add(&call->list, &ftrace_events);
3078         }
3079 
3080         /*
3081          * We need the top trace array to have a working set of trace
3082          * points at early init, before the debug files and directories
3083          * are created. Create the file entries now, and attach them
3084          * to the actual file dentries later.
3085          */
3086         __trace_early_add_events(tr);
3087 
3088         early_enable_events(tr, false);
3089 
3090         trace_printk_start_comm();
3091 
3092         register_event_cmds();
3093 
3094         register_trigger_cmds();
3095 
3096         return 0;
3097 }
3098 
3099 /*
3100  * event_trace_enable() is called from trace_event_init() first to
3101  * initialize events and perhaps start any events that are on the
3102  * command line. Unfortunately, there are some events that will not
3103  * start this early, like the system call tracepoints that need
3104  * to set the TIF_SYSCALL_TRACEPOINT flag of pid 1. But event_trace_enable()
3105  * is called before pid 1 starts, and this flag is never set, making
3106  * the syscall tracepoint never get reached, but the event is enabled
3107  * regardless (and not doing anything).
3108  */
3109 static __init int event_trace_enable_again(void)
3110 {
3111         struct trace_array *tr;
3112 
3113         tr = top_trace_array();
3114         if (!tr)
3115                 return -ENODEV;
3116 
3117         early_enable_events(tr, true);
3118 
3119         return 0;
3120 }
3121 
3122 early_initcall(event_trace_enable_again);
3123 
3124 static __init int event_trace_init(void)
3125 {
3126         struct trace_array *tr;
3127         struct dentry *d_tracer;
3128         struct dentry *entry;
3129         int ret;
3130 
3131         tr = top_trace_array();
3132         if (!tr)
3133                 return -ENODEV;
3134 
3135         d_tracer = tracing_init_dentry();
3136         if (IS_ERR(d_tracer))
3137                 return 0;
3138 
3139         entry = tracefs_create_file("available_events", 0444, d_tracer,
3140                                     tr, &ftrace_avail_fops);
3141         if (!entry)
3142                 pr_warn("Could not create tracefs 'available_events' entry\n");
3143 
3144         if (trace_define_generic_fields())
3145                 pr_warn("tracing: Failed to allocated generic fields");
3146 
3147         if (trace_define_common_fields())
3148                 pr_warn("tracing: Failed to allocate common fields");
3149 
3150         ret = early_event_add_tracer(d_tracer, tr);
3151         if (ret)
3152                 return ret;
3153 
3154 #ifdef CONFIG_MODULES
3155         ret = register_module_notifier(&trace_module_nb);
3156         if (ret)
3157                 pr_warn("Failed to register trace events module notifier\n");
3158 #endif
3159         return 0;
3160 }
3161 
3162 void __init trace_event_init(void)
3163 {
3164         event_trace_memsetup();
3165         init_ftrace_syscalls();
3166         event_trace_enable();
3167 }
3168 
3169 fs_initcall(event_trace_init);
3170 
3171 #ifdef CONFIG_FTRACE_STARTUP_TEST
3172 
3173 static DEFINE_SPINLOCK(test_spinlock);
3174 static DEFINE_SPINLOCK(test_spinlock_irq);
3175 static DEFINE_MUTEX(test_mutex);
3176 
3177 static __init void test_work(struct work_struct *dummy)
3178 {
3179         spin_lock(&test_spinlock);
3180         spin_lock_irq(&test_spinlock_irq);
3181         udelay(1);
3182         spin_unlock_irq(&test_spinlock_irq);
3183         spin_unlock(&test_spinlock);
3184 
3185         mutex_lock(&test_mutex);
3186         msleep(1);
3187         mutex_unlock(&test_mutex);
3188 }
3189 
3190 static __init int event_test_thread(void *unused)
3191 {
3192         void *test_malloc;
3193 
3194         test_malloc = kmalloc(1234, GFP_KERNEL);
3195         if (!test_malloc)
3196                 pr_info("failed to kmalloc\n");
3197 
3198         schedule_on_each_cpu(test_work);
3199 
3200         kfree(test_malloc);
3201 
3202         set_current_state(TASK_INTERRUPTIBLE);
3203         while (!kthread_should_stop()) {
3204                 schedule();
3205                 set_current_state(TASK_INTERRUPTIBLE);
3206         }
3207         __set_current_state(TASK_RUNNING);
3208 
3209         return 0;
3210 }
3211 
3212 /*
3213  * Do various things that may trigger events.
3214  */
3215 static __init void event_test_stuff(void)
3216 {
3217         struct task_struct *test_thread;
3218 
3219         test_thread = kthread_run(event_test_thread, NULL, "test-events");
3220         msleep(1);
3221         kthread_stop(test_thread);
3222 }
3223 
3224 /*
3225  * For every trace event defined, we will test each trace point separately,
3226  * and then by groups, and finally all trace points.
3227  */
3228 static __init void event_trace_self_tests(void)
3229 {
3230         struct trace_subsystem_dir *dir;
3231         struct trace_event_file *file;
3232         struct trace_event_call *call;
3233         struct event_subsystem *system;
3234         struct trace_array *tr;
3235         int ret;
3236 
3237         tr = top_trace_array();
3238         if (!tr)
3239                 return;
3240 
3241         pr_info("Running tests on trace events:\n");
3242 
3243         list_for_each_entry(file, &tr->events, list) {
3244 
3245                 call = file->event_call;
3246 
3247                 /* Only test those that have a probe */
3248                 if (!call->class || !call->class->probe)
3249                         continue;
3250 
3251 /*
3252  * Testing syscall events here is pretty useless, but
3253  * we still do it if configured. But this is time consuming.
3254  * What we really need is a user thread to perform the
3255  * syscalls as we test.
3256  */
3257 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3258                 if (call->class->system &&
3259                     strcmp(call->class->system, "syscalls") == 0)
3260                         continue;
3261 #endif
3262 
3263                 pr_info("Testing event %s: ", trace_event_name(call));
3264 
3265                 /*
3266                  * If an event is already enabled, someone is using
3267                  * it and the self test should not be on.
3268                  */
3269                 if (file->flags & EVENT_FILE_FL_ENABLED) {
3270                         pr_warn("Enabled event during self test!\n");
3271                         WARN_ON_ONCE(1);
3272                         continue;
3273                 }
3274 
3275                 ftrace_event_enable_disable(file, 1);
3276                 event_test_stuff();
3277                 ftrace_event_enable_disable(file, 0);
3278 
3279                 pr_cont("OK\n");
3280         }
3281 
3282         /* Now test at the sub system level */
3283 
3284         pr_info("Running tests on trace event systems:\n");
3285 
3286         list_for_each_entry(dir, &tr->systems, list) {
3287 
3288                 system = dir->subsystem;
3289 
3290                 /* the ftrace system is special, skip it */
3291                 if (strcmp(system->name, "ftrace") == 0)
3292                         continue;
3293 
3294                 pr_info("Testing event system %s: ", system->name);
3295 
3296                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3297                 if (WARN_ON_ONCE(ret)) {
3298                         pr_warn("error enabling system %s\n",
3299                                 system->name);
3300                         continue;
3301                 }
3302 
3303                 event_test_stuff();
3304 
3305                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3306                 if (WARN_ON_ONCE(ret)) {
3307                         pr_warn("error disabling system %s\n",
3308                                 system->name);
3309                         continue;
3310                 }
3311 
3312                 pr_cont("OK\n");
3313         }
3314 
3315         /* Test with all events enabled */
3316 
3317         pr_info("Running tests on all trace events:\n");
3318         pr_info("Testing all events: ");
3319 
3320         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3321         if (WARN_ON_ONCE(ret)) {
3322                 pr_warn("error enabling all events\n");
3323                 return;
3324         }
3325 
3326         event_test_stuff();
3327 
3328         /* reset sysname */
3329         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3330         if (WARN_ON_ONCE(ret)) {
3331                 pr_warn("error disabling all events\n");
3332                 return;
3333         }
3334 
3335         pr_cont("OK\n");
3336 }
3337 
3338 #ifdef CONFIG_FUNCTION_TRACER
3339 
3340 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3341 
3342 static struct trace_event_file event_trace_file __initdata;
3343 
3344 static void __init
3345 function_test_events_call(unsigned long ip, unsigned long parent_ip,
3346                           struct ftrace_ops *op, struct pt_regs *pt_regs)
3347 {
3348         struct ring_buffer_event *event;
3349         struct ring_buffer *buffer;
3350         struct ftrace_entry *entry;
3351         unsigned long flags;
3352         long disabled;
3353         int cpu;
3354         int pc;
3355 
3356         pc = preempt_count();
3357         preempt_disable_notrace();
3358         cpu = raw_smp_processor_id();
3359         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3360 
3361         if (disabled != 1)
3362                 goto out;
3363 
3364         local_save_flags(flags);
3365 
3366         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3367                                                 TRACE_FN, sizeof(*entry),
3368                                                 flags, pc);
3369         if (!event)
3370                 goto out;
3371         entry   = ring_buffer_event_data(event);
3372         entry->ip                       = ip;
3373         entry->parent_ip                = parent_ip;
3374 
3375         event_trigger_unlock_commit(&event_trace_file, buffer, event,
3376                                     entry, flags, pc);
3377  out:
3378         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3379         preempt_enable_notrace();
3380 }
3381 
3382 static struct ftrace_ops trace_ops __initdata  =
3383 {
3384         .func = function_test_events_call,
3385         .flags = FTRACE_OPS_FL_RECURSION_SAFE,
3386 };
3387 
3388 static __init void event_trace_self_test_with_function(void)
3389 {
3390         int ret;
3391 
3392         event_trace_file.tr = top_trace_array();
3393         if (WARN_ON(!event_trace_file.tr))
3394                 return;
3395 
3396         ret = register_ftrace_function(&trace_ops);
3397         if (WARN_ON(ret < 0)) {
3398                 pr_info("Failed to enable function tracer for event tests\n");
3399                 return;
3400         }
3401         pr_info("Running tests again, along with the function tracer\n");
3402         event_trace_self_tests();
3403         unregister_ftrace_function(&trace_ops);
3404 }
3405 #else
3406 static __init void event_trace_self_test_with_function(void)
3407 {
3408 }
3409 #endif
3410 
3411 static __init int event_trace_self_tests_init(void)
3412 {
3413         if (!tracing_selftest_disabled) {
3414                 event_trace_self_tests();
3415                 event_trace_self_test_with_function();
3416         }
3417 
3418         return 0;
3419 }
3420 
3421 late_initcall(event_trace_self_tests_init);
3422 
3423 #endif
3424 

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