kernel/trace/trace_events.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * event tracer
   4  *
   5  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   6  *
   7  *  - Added format output of fields of the trace point.
   8  *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) fmt
  13
  14 #include <linux/workqueue.h>
  15 #include <linux/security.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/kthread.h>
  18 #include <linux/tracefs.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/module.h>
  21 #include <linux/ctype.h>
  22 #include <linux/sort.h>
  23 #include <linux/slab.h>
  24 #include <linux/delay.h>
  25
  26 #include <trace/events/sched.h>
  27 #include <trace/syscall.h>
  28
  29 #include <asm/setup.h>
  30
  31 #include "trace_output.h"
  32
  33 #undef TRACE_SYSTEM
  34 #define TRACE_SYSTEM "TRACE_SYSTEM"
  35
  36 DEFINE_MUTEX(event_mutex);
  37
  38 LIST_HEAD(ftrace_events);
  39 static LIST_HEAD(ftrace_generic_fields);
  40 static LIST_HEAD(ftrace_common_fields);
  41 static bool eventdir_initialized;
  42
  43 #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO)
  44
  45 static struct kmem_cache *field_cachep;
  46 static struct kmem_cache *file_cachep;
  47
  48 static inline int system_refcount(struct event_subsystem *system)
  49 {
  50         return system->ref_count;
  51 }
  52
  53 static int system_refcount_inc(struct event_subsystem *system)
  54 {
  55         return system->ref_count++;
  56 }
  57
  58 static int system_refcount_dec(struct event_subsystem *system)
  59 {
  60         return --system->ref_count;
  61 }
  62
  63 /* Double loops, do not use break, only goto's work */
  64 #define do_for_each_event_file(tr, file)                        \
  65         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  66                 list_for_each_entry(file, &tr->events, list)
  67
  68 #define do_for_each_event_file_safe(tr, file)                   \
  69         list_for_each_entry(tr, &ftrace_trace_arrays, list) {   \
  70                 struct trace_event_file *___n;                          \
  71                 list_for_each_entry_safe(file, ___n, &tr->events, list)
  72
  73 #define while_for_each_event_file()             \
  74         }
  75
  76 static struct ftrace_event_field *
  77 __find_event_field(struct list_head *head, char *name)
  78 {
  79         struct ftrace_event_field *field;
  80
  81         list_for_each_entry(field, head, link) {
  82                 if (!strcmp(field->name, name))
  83                         return field;
  84         }
  85
  86         return NULL;
  87 }
  88
  89 struct ftrace_event_field *
  90 trace_find_event_field(struct trace_event_call *call, char *name)
  91 {
  92         struct ftrace_event_field *field;
  93         struct list_head *head;
  94
  95         head = trace_get_fields(call);
  96         field = __find_event_field(head, name);
  97         if (field)
  98                 return field;
  99
 100         field = __find_event_field(&ftrace_generic_fields, name);
 101         if (field)
 102                 return field;
 103
 104         return __find_event_field(&ftrace_common_fields, name);
 105 }
 106
 107 static int __trace_define_field(struct list_head *head, const char *type,
 108                                 const char *name, int offset, int size,
 109                                 int is_signed, int filter_type)
 110 {
 111         struct ftrace_event_field *field;
 112
 113         field = kmem_cache_alloc(field_cachep, GFP_TRACE);
 114         if (!field)
 115                 return -ENOMEM;
 116
 117         field->name = name;
 118         field->type = type;
 119
 120         if (filter_type == FILTER_OTHER)
 121                 field->filter_type = filter_assign_type(type);
 122         else
 123                 field->filter_type = filter_type;
 124
 125         field->offset = offset;
 126         field->size = size;
 127         field->is_signed = is_signed;
 128
 129         list_add(&field->link, head);
 130
 131         return 0;
 132 }
 133
 134 int trace_define_field(struct trace_event_call *call, const char *type,
 135                        const char *name, int offset, int size, int is_signed,
 136                        int filter_type)
 137 {
 138         struct list_head *head;
 139
 140         if (WARN_ON(!call->class))
 141                 return 0;
 142
 143         head = trace_get_fields(call);
 144         return __trace_define_field(head, type, name, offset, size,
 145                                     is_signed, filter_type);
 146 }
 147 EXPORT_SYMBOL_GPL(trace_define_field);
 148
 149 #define __generic_field(type, item, filter_type)                        \
 150         ret = __trace_define_field(&ftrace_generic_fields, #type,       \
 151                                    #item, 0, 0, is_signed_type(type),   \
 152                                    filter_type);                        \
 153         if (ret)                                                        \
 154                 return ret;
 155
 156 #define __common_field(type, item)                                      \
 157         ret = __trace_define_field(&ftrace_common_fields, #type,        \
 158                                    "common_" #item,                     \
 159                                    offsetof(typeof(ent), item),         \
 160                                    sizeof(ent.item),                    \
 161                                    is_signed_type(type), FILTER_OTHER); \
 162         if (ret)                                                        \
 163                 return ret;
 164
 165 static int trace_define_generic_fields(void)
 166 {
 167         int ret;
 168
 169         __generic_field(int, CPU, FILTER_CPU);
 170         __generic_field(int, cpu, FILTER_CPU);
 171         __generic_field(char *, COMM, FILTER_COMM);
 172         __generic_field(char *, comm, FILTER_COMM);
 173
 174         return ret;
 175 }
 176
 177 static int trace_define_common_fields(void)
 178 {
 179         int ret;
 180         struct trace_entry ent;
 181
 182         __common_field(unsigned short, type);
 183         __common_field(unsigned char, flags);
 184         __common_field(unsigned char, preempt_count);
 185         __common_field(int, pid);
 186
 187         return ret;
 188 }
 189
 190 static void trace_destroy_fields(struct trace_event_call *call)
 191 {
 192         struct ftrace_event_field *field, *next;
 193         struct list_head *head;
 194
 195         head = trace_get_fields(call);
 196         list_for_each_entry_safe(field, next, head, link) {
 197                 list_del(&field->link);
 198                 kmem_cache_free(field_cachep, field);
 199         }
 200 }
 201
 202 /*
 203  * run-time version of trace_event_get_offsets_<call>() that returns the last
 204  * accessible offset of trace fields excluding __dynamic_array bytes
 205  */
 206 int trace_event_get_offsets(struct trace_event_call *call)
 207 {
 208         struct ftrace_event_field *tail;
 209         struct list_head *head;
 210
 211         head = trace_get_fields(call);
 212         /*
 213          * head->next points to the last field with the largest offset,
 214          * since it was added last by trace_define_field()
 215          */
 216         tail = list_first_entry(head, struct ftrace_event_field, link);
 217         return tail->offset + tail->size;
 218 }
 219
 220 int trace_event_raw_init(struct trace_event_call *call)
 221 {
 222         int id;
 223
 224         id = register_trace_event(&call->event);
 225         if (!id)
 226                 return -ENODEV;
 227
 228         return 0;
 229 }
 230 EXPORT_SYMBOL_GPL(trace_event_raw_init);
 231
 232 bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 233 {
 234         struct trace_array *tr = trace_file->tr;
 235         struct trace_array_cpu *data;
 236         struct trace_pid_list *no_pid_list;
 237         struct trace_pid_list *pid_list;
 238
 239         pid_list = rcu_dereference_raw(tr->filtered_pids);
 240         no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
 241
 242         if (!pid_list && !no_pid_list)
 243                 return false;
 244
 245         data = this_cpu_ptr(tr->array_buffer.data);
 246
 247         return data->ignore_pid;
 248 }
 249 EXPORT_SYMBOL_GPL(trace_event_ignore_this_pid);
 250
 251 void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 252                                  struct trace_event_file *trace_file,
 253                                  unsigned long len)
 254 {
 255         struct trace_event_call *event_call = trace_file->event_call;
 256
 257         if ((trace_file->flags & EVENT_FILE_FL_PID_FILTER) &&
 258             trace_event_ignore_this_pid(trace_file))
 259                 return NULL;
 260
 261         /*
 262          * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
 263          * preemption (adding one to the preempt_count). Since we are
 264          * interested in the preempt_count at the time the tracepoint was
 265          * hit, we need to subtract one to offset the increment.
 266          */
 267         fbuffer->trace_ctx = tracing_gen_ctx_dec();
 268         fbuffer->trace_file = trace_file;
 269
 270         fbuffer->event =
 271                 trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
 272                                                 event_call->event.type, len,
 273                                                 fbuffer->trace_ctx);
 274         if (!fbuffer->event)
 275                 return NULL;
 276
 277         fbuffer->regs = NULL;
 278         fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 279         return fbuffer->entry;
 280 }
 281 EXPORT_SYMBOL_GPL(trace_event_buffer_reserve);
 282
 283 int trace_event_reg(struct trace_event_call *call,
 284                     enum trace_reg type, void *data)
 285 {
 286         struct trace_event_file *file = data;
 287
 288         WARN_ON(!(call->flags & TRACE_EVENT_FL_TRACEPOINT));
 289         switch (type) {
 290         case TRACE_REG_REGISTER:
 291                 return tracepoint_probe_register(call->tp,
 292                                                  call->class->probe,
 293                                                  file);
 294         case TRACE_REG_UNREGISTER:
 295                 tracepoint_probe_unregister(call->tp,
 296                                             call->class->probe,
 297                                             file);
 298                 return 0;
 299
 300 #ifdef CONFIG_PERF_EVENTS
 301         case TRACE_REG_PERF_REGISTER:
 302                 return tracepoint_probe_register(call->tp,
 303                                                  call->class->perf_probe,
 304                                                  call);
 305         case TRACE_REG_PERF_UNREGISTER:
 306                 tracepoint_probe_unregister(call->tp,
 307                                             call->class->perf_probe,
 308                                             call);
 309                 return 0;
 310         case TRACE_REG_PERF_OPEN:
 311         case TRACE_REG_PERF_CLOSE:
 312         case TRACE_REG_PERF_ADD:
 313         case TRACE_REG_PERF_DEL:
 314                 return 0;
 315 #endif
 316         }
 317         return 0;
 318 }
 319 EXPORT_SYMBOL_GPL(trace_event_reg);
 320
 321 void trace_event_enable_cmd_record(bool enable)
 322 {
 323         struct trace_event_file *file;
 324         struct trace_array *tr;
 325
 326         lockdep_assert_held(&event_mutex);
 327
 328         do_for_each_event_file(tr, file) {
 329
 330                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 331                         continue;
 332
 333                 if (enable) {
 334                         tracing_start_cmdline_record();
 335                         set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 336                 } else {
 337                         tracing_stop_cmdline_record();
 338                         clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 339                 }
 340         } while_for_each_event_file();
 341 }
 342
 343 void trace_event_enable_tgid_record(bool enable)
 344 {
 345         struct trace_event_file *file;
 346         struct trace_array *tr;
 347
 348         lockdep_assert_held(&event_mutex);
 349
 350         do_for_each_event_file(tr, file) {
 351                 if (!(file->flags & EVENT_FILE_FL_ENABLED))
 352                         continue;
 353
 354                 if (enable) {
 355                         tracing_start_tgid_record();
 356                         set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 357                 } else {
 358                         tracing_stop_tgid_record();
 359                         clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
 360                                   &file->flags);
 361                 }
 362         } while_for_each_event_file();
 363 }
 364
 365 static int __ftrace_event_enable_disable(struct trace_event_file *file,
 366                                          int enable, int soft_disable)
 367 {
 368         struct trace_event_call *call = file->event_call;
 369         struct trace_array *tr = file->tr;
 370         unsigned long file_flags = file->flags;
 371         int ret = 0;
 372         int disable;
 373
 374         switch (enable) {
 375         case 0:
 376                 /*
 377                  * When soft_disable is set and enable is cleared, the sm_ref
 378                  * reference counter is decremented. If it reaches 0, we want
 379                  * to clear the SOFT_DISABLED flag but leave the event in the
 380                  * state that it was. That is, if the event was enabled and
 381                  * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
 382                  * is set we do not want the event to be enabled before we
 383                  * clear the bit.
 384                  *
 385                  * When soft_disable is not set but the SOFT_MODE flag is,
 386                  * we do nothing. Do not disable the tracepoint, otherwise
 387                  * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 388                  */
 389                 if (soft_disable) {
 390                         if (atomic_dec_return(&file->sm_ref) > 0)
 391                                 break;
 392                         disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 393                         clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 394                 } else
 395                         disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 396
 397                 if (disable && (file->flags & EVENT_FILE_FL_ENABLED)) {
 398                         clear_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 399                         if (file->flags & EVENT_FILE_FL_RECORDED_CMD) {
 400                                 tracing_stop_cmdline_record();
 401                                 clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 402                         }
 403
 404                         if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
 405                                 tracing_stop_tgid_record();
 406                                 clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 407                         }
 408
 409                         call->class->reg(call, TRACE_REG_UNREGISTER, file);
 410                 }
 411                 /* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
 412                 if (file->flags & EVENT_FILE_FL_SOFT_MODE)
 413                         set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 414                 else
 415                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 416                 break;
 417         case 1:
 418                 /*
 419                  * When soft_disable is set and enable is set, we want to
 420                  * register the tracepoint for the event, but leave the event
 421                  * as is. That means, if the event was already enabled, we do
 422                  * nothing (but set SOFT_MODE). If the event is disabled, we
 423                  * set SOFT_DISABLED before enabling the event tracepoint, so
 424                  * it still seems to be disabled.
 425                  */
 426                 if (!soft_disable)
 427                         clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 428                 else {
 429                         if (atomic_inc_return(&file->sm_ref) > 1)
 430                                 break;
 431                         set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
 432                 }
 433
 434                 if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
 435                         bool cmd = false, tgid = false;
 436
 437                         /* Keep the event disabled, when going to SOFT_MODE. */
 438                         if (soft_disable)
 439                                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
 440
 441                         if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
 442                                 cmd = true;
 443                                 tracing_start_cmdline_record();
 444                                 set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
 445                         }
 446
 447                         if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
 448                                 tgid = true;
 449                                 tracing_start_tgid_record();
 450                                 set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
 451                         }
 452
 453                         ret = call->class->reg(call, TRACE_REG_REGISTER, file);
 454                         if (ret) {
 455                                 if (cmd)
 456                                         tracing_stop_cmdline_record();
 457                                 if (tgid)
 458                                         tracing_stop_tgid_record();
 459                                 pr_info("event trace: Could not enable event "
 460                                         "%s\n", trace_event_name(call));
 461                                 break;
 462                         }
 463                         set_bit(EVENT_FILE_FL_ENABLED_BIT, &file->flags);
 464
 465                         /* WAS_ENABLED gets set but never cleared. */
 466                         set_bit(EVENT_FILE_FL_WAS_ENABLED_BIT, &file->flags);
 467                 }
 468                 break;
 469         }
 470
 471         /* Enable or disable use of trace_buffered_event */
 472         if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
 473             (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
 474                 if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
 475                         trace_buffered_event_enable();
 476                 else
 477                         trace_buffered_event_disable();
 478         }
 479
 480         return ret;
 481 }
 482
 483 int trace_event_enable_disable(struct trace_event_file *file,
 484                                int enable, int soft_disable)
 485 {
 486         return __ftrace_event_enable_disable(file, enable, soft_disable);
 487 }
 488
 489 static int ftrace_event_enable_disable(struct trace_event_file *file,
 490                                        int enable)
 491 {
 492         return __ftrace_event_enable_disable(file, enable, 0);
 493 }
 494
 495 static void ftrace_clear_events(struct trace_array *tr)
 496 {
 497         struct trace_event_file *file;
 498
 499         mutex_lock(&event_mutex);
 500         list_for_each_entry(file, &tr->events, list) {
 501                 ftrace_event_enable_disable(file, 0);
 502         }
 503         mutex_unlock(&event_mutex);
 504 }
 505
 506 static void
 507 event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 508 {
 509         struct trace_pid_list *pid_list;
 510         struct trace_array *tr = data;
 511
 512         pid_list = rcu_dereference_raw(tr->filtered_pids);
 513         trace_filter_add_remove_task(pid_list, NULL, task);
 514
 515         pid_list = rcu_dereference_raw(tr->filtered_no_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         pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 531         trace_filter_add_remove_task(pid_list, self, task);
 532 }
 533
 534 void trace_event_follow_fork(struct trace_array *tr, bool enable)
 535 {
 536         if (enable) {
 537                 register_trace_prio_sched_process_fork(event_filter_pid_sched_process_fork,
 538                                                        tr, INT_MIN);
 539                 register_trace_prio_sched_process_free(event_filter_pid_sched_process_exit,
 540                                                        tr, INT_MAX);
 541         } else {
 542                 unregister_trace_sched_process_fork(event_filter_pid_sched_process_fork,
 543                                                     tr);
 544                 unregister_trace_sched_process_free(event_filter_pid_sched_process_exit,
 545                                                     tr);
 546         }
 547 }
 548
 549 static void
 550 event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 551                     struct task_struct *prev, struct task_struct *next)
 552 {
 553         struct trace_array *tr = data;
 554         struct trace_pid_list *no_pid_list;
 555         struct trace_pid_list *pid_list;
 556         bool ret;
 557
 558         pid_list = rcu_dereference_sched(tr->filtered_pids);
 559         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 560
 561         /*
 562          * Sched switch is funny, as we only want to ignore it
 563          * in the notrace case if both prev and next should be ignored.
 564          */
 565         ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
 566                 trace_ignore_this_task(NULL, no_pid_list, next);
 567
 568         this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
 569                        (trace_ignore_this_task(pid_list, NULL, prev) &&
 570                         trace_ignore_this_task(pid_list, NULL, next)));
 571 }
 572
 573 static void
 574 event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 575                     struct task_struct *prev, struct task_struct *next)
 576 {
 577         struct trace_array *tr = data;
 578         struct trace_pid_list *no_pid_list;
 579         struct trace_pid_list *pid_list;
 580
 581         pid_list = rcu_dereference_sched(tr->filtered_pids);
 582         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 583
 584         this_cpu_write(tr->array_buffer.data->ignore_pid,
 585                        trace_ignore_this_task(pid_list, no_pid_list, next));
 586 }
 587
 588 static void
 589 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 590 {
 591         struct trace_array *tr = data;
 592         struct trace_pid_list *no_pid_list;
 593         struct trace_pid_list *pid_list;
 594
 595         /* Nothing to do if we are already tracing */
 596         if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 597                 return;
 598
 599         pid_list = rcu_dereference_sched(tr->filtered_pids);
 600         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 601
 602         this_cpu_write(tr->array_buffer.data->ignore_pid,
 603                        trace_ignore_this_task(pid_list, no_pid_list, task));
 604 }
 605
 606 static void
 607 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 608 {
 609         struct trace_array *tr = data;
 610         struct trace_pid_list *no_pid_list;
 611         struct trace_pid_list *pid_list;
 612
 613         /* Nothing to do if we are not tracing */
 614         if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 615                 return;
 616
 617         pid_list = rcu_dereference_sched(tr->filtered_pids);
 618         no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 619
 620         /* Set tracing if current is enabled */
 621         this_cpu_write(tr->array_buffer.data->ignore_pid,
 622                        trace_ignore_this_task(pid_list, no_pid_list, current));
 623 }
 624
 625 static void unregister_pid_events(struct trace_array *tr)
 626 {
 627         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 628         unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 629
 630         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre, tr);
 631         unregister_trace_sched_wakeup(event_filter_pid_sched_wakeup_probe_post, tr);
 632
 633         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre, tr);
 634         unregister_trace_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post, tr);
 635
 636         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 637         unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
 638 }
 639
 640 static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
 641 {
 642         struct trace_pid_list *pid_list;
 643         struct trace_pid_list *no_pid_list;
 644         struct trace_event_file *file;
 645         int cpu;
 646
 647         pid_list = rcu_dereference_protected(tr->filtered_pids,
 648                                              lockdep_is_held(&event_mutex));
 649         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
 650                                              lockdep_is_held(&event_mutex));
 651
 652         /* Make sure there's something to do */
 653         if (!pid_type_enabled(type, pid_list, no_pid_list))
 654                 return;
 655
 656         if (!still_need_pid_events(type, pid_list, no_pid_list)) {
 657                 unregister_pid_events(tr);
 658
 659                 list_for_each_entry(file, &tr->events, list) {
 660                         clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
 661                 }
 662
 663                 for_each_possible_cpu(cpu)
 664                         per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 665         }
 666
 667         if (type & TRACE_PIDS)
 668                 rcu_assign_pointer(tr->filtered_pids, NULL);
 669
 670         if (type & TRACE_NO_PIDS)
 671                 rcu_assign_pointer(tr->filtered_no_pids, NULL);
 672
 673         /* Wait till all users are no longer using pid filtering */
 674         tracepoint_synchronize_unregister();
 675
 676         if ((type & TRACE_PIDS) && pid_list)
 677                 trace_free_pid_list(pid_list);
 678
 679         if ((type & TRACE_NO_PIDS) && no_pid_list)
 680                 trace_free_pid_list(no_pid_list);
 681 }
 682
 683 static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 684 {
 685         mutex_lock(&event_mutex);
 686         __ftrace_clear_event_pids(tr, type);
 687         mutex_unlock(&event_mutex);
 688 }
 689
 690 static void __put_system(struct event_subsystem *system)
 691 {
 692         struct event_filter *filter = system->filter;
 693
 694         WARN_ON_ONCE(system_refcount(system) == 0);
 695         if (system_refcount_dec(system))
 696                 return;
 697
 698         list_del(&system->list);
 699
 700         if (filter) {
 701                 kfree(filter->filter_string);
 702                 kfree(filter);
 703         }
 704         kfree_const(system->name);
 705         kfree(system);
 706 }
 707
 708 static void __get_system(struct event_subsystem *system)
 709 {
 710         WARN_ON_ONCE(system_refcount(system) == 0);
 711         system_refcount_inc(system);
 712 }
 713
 714 static void __get_system_dir(struct trace_subsystem_dir *dir)
 715 {
 716         WARN_ON_ONCE(dir->ref_count == 0);
 717         dir->ref_count++;
 718         __get_system(dir->subsystem);
 719 }
 720
 721 static void __put_system_dir(struct trace_subsystem_dir *dir)
 722 {
 723         WARN_ON_ONCE(dir->ref_count == 0);
 724         /* If the subsystem is about to be freed, the dir must be too */
 725         WARN_ON_ONCE(system_refcount(dir->subsystem) == 1 && dir->ref_count != 1);
 726
 727         __put_system(dir->subsystem);
 728         if (!--dir->ref_count)
 729                 kfree(dir);
 730 }
 731
 732 static void put_system(struct trace_subsystem_dir *dir)
 733 {
 734         mutex_lock(&event_mutex);
 735         __put_system_dir(dir);
 736         mutex_unlock(&event_mutex);
 737 }
 738
 739 static void remove_subsystem(struct trace_subsystem_dir *dir)
 740 {
 741         if (!dir)
 742                 return;
 743
 744         if (!--dir->nr_events) {
 745                 tracefs_remove(dir->entry);
 746                 list_del(&dir->list);
 747                 __put_system_dir(dir);
 748         }
 749 }
 750
 751 static void remove_event_file_dir(struct trace_event_file *file)
 752 {
 753         struct dentry *dir = file->dir;
 754         struct dentry *child;
 755
 756         if (dir) {
 757                 spin_lock(&dir->d_lock);        /* probably unneeded */
 758                 list_for_each_entry(child, &dir->d_subdirs, d_child) {
 759                         if (d_really_is_positive(child))        /* probably unneeded */
 760                                 d_inode(child)->i_private = NULL;
 761                 }
 762                 spin_unlock(&dir->d_lock);
 763
 764                 tracefs_remove(dir);
 765         }
 766
 767         list_del(&file->list);
 768         remove_subsystem(file->system);
 769         free_event_filter(file->filter);
 770         kmem_cache_free(file_cachep, file);
 771 }
 772
 773 /*
 774  * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 775  */
 776 static int
 777 __ftrace_set_clr_event_nolock(struct trace_array *tr, const char *match,
 778                               const char *sub, const char *event, int set)
 779 {
 780         struct trace_event_file *file;
 781         struct trace_event_call *call;
 782         const char *name;
 783         int ret = -EINVAL;
 784         int eret = 0;
 785
 786         list_for_each_entry(file, &tr->events, list) {
 787
 788                 call = file->event_call;
 789                 name = trace_event_name(call);
 790
 791                 if (!name || !call->class || !call->class->reg)
 792                         continue;
 793
 794                 if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
 795                         continue;
 796
 797                 if (match &&
 798                     strcmp(match, name) != 0 &&
 799                     strcmp(match, call->class->system) != 0)
 800                         continue;
 801
 802                 if (sub && strcmp(sub, call->class->system) != 0)
 803                         continue;
 804
 805                 if (event && strcmp(event, name) != 0)
 806                         continue;
 807
 808                 ret = ftrace_event_enable_disable(file, set);
 809
 810                 /*
 811                  * Save the first error and return that. Some events
 812                  * may still have been enabled, but let the user
 813                  * know that something went wrong.
 814                  */
 815                 if (ret && !eret)
 816                         eret = ret;
 817
 818                 ret = eret;
 819         }
 820
 821         return ret;
 822 }
 823
 824 static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
 825                                   const char *sub, const char *event, int set)
 826 {
 827         int ret;
 828
 829         mutex_lock(&event_mutex);
 830         ret = __ftrace_set_clr_event_nolock(tr, match, sub, event, set);
 831         mutex_unlock(&event_mutex);
 832
 833         return ret;
 834 }
 835
 836 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
 837 {
 838         char *event = NULL, *sub = NULL, *match;
 839         int ret;
 840
 841         if (!tr)
 842                 return -ENOENT;
 843         /*
 844          * The buf format can be <subsystem>:<event-name>
 845          *  *:<event-name> means any event by that name.
 846          *  :<event-name> is the same.
 847          *
 848          *  <subsystem>:* means all events in that subsystem
 849          *  <subsystem>: means the same.
 850          *
 851          *  <name> (no ':') means all events in a subsystem with
 852          *  the name <name> or any event that matches <name>
 853          */
 854
 855         match = strsep(&buf, ":");
 856         if (buf) {
 857                 sub = match;
 858                 event = buf;
 859                 match = NULL;
 860
 861                 if (!strlen(sub) || strcmp(sub, "*") == 0)
 862                         sub = NULL;
 863                 if (!strlen(event) || strcmp(event, "*") == 0)
 864                         event = NULL;
 865         }
 866
 867         ret = __ftrace_set_clr_event(tr, match, sub, event, set);
 868
 869         /* Put back the colon to allow this to be called again */
 870         if (buf)
 871                 *(buf - 1) = ':';
 872
 873         return ret;
 874 }
 875
 876 /**
 877  * trace_set_clr_event - enable or disable an event
 878  * @system: system name to match (NULL for any system)
 879  * @event: event name to match (NULL for all events, within system)
 880  * @set: 1 to enable, 0 to disable
 881  *
 882  * This is a way for other parts of the kernel to enable or disable
 883  * event recording.
 884  *
 885  * Returns 0 on success, -EINVAL if the parameters do not match any
 886  * registered events.
 887  */
 888 int trace_set_clr_event(const char *system, const char *event, int set)
 889 {
 890         struct trace_array *tr = top_trace_array();
 891
 892         if (!tr)
 893                 return -ENODEV;
 894
 895         return __ftrace_set_clr_event(tr, NULL, system, event, set);
 896 }
 897 EXPORT_SYMBOL_GPL(trace_set_clr_event);
 898
 899 /**
 900  * trace_array_set_clr_event - enable or disable an event for a trace array.
 901  * @tr: concerned trace array.
 902  * @system: system name to match (NULL for any system)
 903  * @event: event name to match (NULL for all events, within system)
 904  * @enable: true to enable, false to disable
 905  *
 906  * This is a way for other parts of the kernel to enable or disable
 907  * event recording.
 908  *
 909  * Returns 0 on success, -EINVAL if the parameters do not match any
 910  * registered events.
 911  */
 912 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
 913                 const char *event, bool enable)
 914 {
 915         int set;
 916
 917         if (!tr)
 918                 return -ENOENT;
 919
 920         set = (enable == true) ? 1 : 0;
 921         return __ftrace_set_clr_event(tr, NULL, system, event, set);
 922 }
 923 EXPORT_SYMBOL_GPL(trace_array_set_clr_event);
 924
 925 /* 128 should be much more than enough */
 926 #define EVENT_BUF_SIZE          127
 927
 928 static ssize_t
 929 ftrace_event_write(struct file *file, const char __user *ubuf,
 930                    size_t cnt, loff_t *ppos)
 931 {
 932         struct trace_parser parser;
 933         struct seq_file *m = file->private_data;
 934         struct trace_array *tr = m->private;
 935         ssize_t read, ret;
 936
 937         if (!cnt)
 938                 return 0;
 939
 940         ret = tracing_update_buffers();
 941         if (ret < 0)
 942                 return ret;
 943
 944         if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
 945                 return -ENOMEM;
 946
 947         read = trace_get_user(&parser, ubuf, cnt, ppos);
 948
 949         if (read >= 0 && trace_parser_loaded((&parser))) {
 950                 int set = 1;
 951
 952                 if (*parser.buffer == '!')
 953                         set = 0;
 954
 955                 ret = ftrace_set_clr_event(tr, parser.buffer + !set, set);
 956                 if (ret)
 957                         goto out_put;
 958         }
 959
 960         ret = read;
 961
 962  out_put:
 963         trace_parser_put(&parser);
 964
 965         return ret;
 966 }
 967
 968 static void *
 969 t_next(struct seq_file *m, void *v, loff_t *pos)
 970 {
 971         struct trace_event_file *file = v;
 972         struct trace_event_call *call;
 973         struct trace_array *tr = m->private;
 974
 975         (*pos)++;
 976
 977         list_for_each_entry_continue(file, &tr->events, list) {
 978                 call = file->event_call;
 979                 /*
 980                  * The ftrace subsystem is for showing formats only.
 981                  * They can not be enabled or disabled via the event files.
 982                  */
 983                 if (call->class && call->class->reg &&
 984                     !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
 985                         return file;
 986         }
 987
 988         return NULL;
 989 }
 990
 991 static void *t_start(struct seq_file *m, loff_t *pos)
 992 {
 993         struct trace_event_file *file;
 994         struct trace_array *tr = m->private;
 995         loff_t l;
 996
 997         mutex_lock(&event_mutex);
 998
 999         file = list_entry(&tr->events, struct trace_event_file, list);
1000         for (l = 0; l <= *pos; ) {
1001                 file = t_next(m, file, &l);
1002                 if (!file)
1003                         break;
1004         }
1005         return file;
1006 }
1007
1008 static void *
1009 s_next(struct seq_file *m, void *v, loff_t *pos)
1010 {
1011         struct trace_event_file *file = v;
1012         struct trace_array *tr = m->private;
1013
1014         (*pos)++;
1015
1016         list_for_each_entry_continue(file, &tr->events, list) {
1017                 if (file->flags & EVENT_FILE_FL_ENABLED)
1018                         return file;
1019         }
1020
1021         return NULL;
1022 }
1023
1024 static void *s_start(struct seq_file *m, loff_t *pos)
1025 {
1026         struct trace_event_file *file;
1027         struct trace_array *tr = m->private;
1028         loff_t l;
1029
1030         mutex_lock(&event_mutex);
1031
1032         file = list_entry(&tr->events, struct trace_event_file, list);
1033         for (l = 0; l <= *pos; ) {
1034                 file = s_next(m, file, &l);
1035                 if (!file)
1036                         break;
1037         }
1038         return file;
1039 }
1040
1041 static int t_show(struct seq_file *m, void *v)
1042 {
1043         struct trace_event_file *file = v;
1044         struct trace_event_call *call = file->event_call;
1045
1046         if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1047                 seq_printf(m, "%s:", call->class->system);
1048         seq_printf(m, "%s\n", trace_event_name(call));
1049
1050         return 0;
1051 }
1052
1053 static void t_stop(struct seq_file *m, void *p)
1054 {
1055         mutex_unlock(&event_mutex);
1056 }
1057
1058 static void *
1059 __next(struct seq_file *m, void *v, loff_t *pos, int type)
1060 {
1061         struct trace_array *tr = m->private;
1062         struct trace_pid_list *pid_list;
1063
1064         if (type == TRACE_PIDS)
1065                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1066         else
1067                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1068
1069         return trace_pid_next(pid_list, v, pos);
1070 }
1071
1072 static void *
1073 p_next(struct seq_file *m, void *v, loff_t *pos)
1074 {
1075         return __next(m, v, pos, TRACE_PIDS);
1076 }
1077
1078 static void *
1079 np_next(struct seq_file *m, void *v, loff_t *pos)
1080 {
1081         return __next(m, v, pos, TRACE_NO_PIDS);
1082 }
1083
1084 static void *__start(struct seq_file *m, loff_t *pos, int type)
1085         __acquires(RCU)
1086 {
1087         struct trace_pid_list *pid_list;
1088         struct trace_array *tr = m->private;
1089
1090         /*
1091          * Grab the mutex, to keep calls to p_next() having the same
1092          * tr->filtered_pids as p_start() has.
1093          * If we just passed the tr->filtered_pids around, then RCU would
1094          * have been enough, but doing that makes things more complex.
1095          */
1096         mutex_lock(&event_mutex);
1097         rcu_read_lock_sched();
1098
1099         if (type == TRACE_PIDS)
1100                 pid_list = rcu_dereference_sched(tr->filtered_pids);
1101         else
1102                 pid_list = rcu_dereference_sched(tr->filtered_no_pids);
1103
1104         if (!pid_list)
1105                 return NULL;
1106
1107         return trace_pid_start(pid_list, pos);
1108 }
1109
1110 static void *p_start(struct seq_file *m, loff_t *pos)
1111         __acquires(RCU)
1112 {
1113         return __start(m, pos, TRACE_PIDS);
1114 }
1115
1116 static void *np_start(struct seq_file *m, loff_t *pos)
1117         __acquires(RCU)
1118 {
1119         return __start(m, pos, TRACE_NO_PIDS);
1120 }
1121
1122 static void p_stop(struct seq_file *m, void *p)
1123         __releases(RCU)
1124 {
1125         rcu_read_unlock_sched();
1126         mutex_unlock(&event_mutex);
1127 }
1128
1129 static ssize_t
1130 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1131                   loff_t *ppos)
1132 {
1133         struct trace_event_file *file;
1134         unsigned long flags;
1135         char buf[4] = "0";
1136
1137         mutex_lock(&event_mutex);
1138         file = event_file_data(filp);
1139         if (likely(file))
1140                 flags = file->flags;
1141         mutex_unlock(&event_mutex);
1142
1143         if (!file)
1144                 return -ENODEV;
1145
1146         if (flags & EVENT_FILE_FL_ENABLED &&
1147             !(flags & EVENT_FILE_FL_SOFT_DISABLED))
1148                 strcpy(buf, "1");
1149
1150         if (flags & EVENT_FILE_FL_SOFT_DISABLED ||
1151             flags & EVENT_FILE_FL_SOFT_MODE)
1152                 strcat(buf, "*");
1153
1154         strcat(buf, "\n");
1155
1156         return simple_read_from_buffer(ubuf, cnt, ppos, buf, strlen(buf));
1157 }
1158
1159 static ssize_t
1160 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1161                    loff_t *ppos)
1162 {
1163         struct trace_event_file *file;
1164         unsigned long val;
1165         int ret;
1166
1167         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1168         if (ret)
1169                 return ret;
1170
1171         ret = tracing_update_buffers();
1172         if (ret < 0)
1173                 return ret;
1174
1175         switch (val) {
1176         case 0:
1177         case 1:
1178                 ret = -ENODEV;
1179                 mutex_lock(&event_mutex);
1180                 file = event_file_data(filp);
1181                 if (likely(file))
1182                         ret = ftrace_event_enable_disable(file, val);
1183                 mutex_unlock(&event_mutex);
1184                 break;
1185
1186         default:
1187                 return -EINVAL;
1188         }
1189
1190         *ppos += cnt;
1191
1192         return ret ? ret : cnt;
1193 }
1194
1195 static ssize_t
1196 system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
1197                    loff_t *ppos)
1198 {
1199         const char set_to_char[4] = { '?', '0', '1', 'X' };
1200         struct trace_subsystem_dir *dir = filp->private_data;
1201         struct event_subsystem *system = dir->subsystem;
1202         struct trace_event_call *call;
1203         struct trace_event_file *file;
1204         struct trace_array *tr = dir->tr;
1205         char buf[2];
1206         int set = 0;
1207         int ret;
1208
1209         mutex_lock(&event_mutex);
1210         list_for_each_entry(file, &tr->events, list) {
1211                 call = file->event_call;
1212                 if ((call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
1213                     !trace_event_name(call) || !call->class || !call->class->reg)
1214                         continue;
1215
1216                 if (system && strcmp(call->class->system, system->name) != 0)
1217                         continue;
1218
1219                 /*
1220                  * We need to find out if all the events are set
1221                  * or if all events or cleared, or if we have
1222                  * a mixture.
1223                  */
1224                 set |= (1 << !!(file->flags & EVENT_FILE_FL_ENABLED));
1225
1226                 /*
1227                  * If we have a mixture, no need to look further.
1228                  */
1229                 if (set == 3)
1230                         break;
1231         }
1232         mutex_unlock(&event_mutex);
1233
1234         buf[0] = set_to_char[set];
1235         buf[1] = '\n';
1236
1237         ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
1238
1239         return ret;
1240 }
1241
1242 static ssize_t
1243 system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
1244                     loff_t *ppos)
1245 {
1246         struct trace_subsystem_dir *dir = filp->private_data;
1247         struct event_subsystem *system = dir->subsystem;
1248         const char *name = NULL;
1249         unsigned long val;
1250         ssize_t ret;
1251
1252         ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
1253         if (ret)
1254                 return ret;
1255
1256         ret = tracing_update_buffers();
1257         if (ret < 0)
1258                 return ret;
1259
1260         if (val != 0 && val != 1)
1261                 return -EINVAL;
1262
1263         /*
1264          * Opening of "enable" adds a ref count to system,
1265          * so the name is safe to use.
1266          */
1267         if (system)
1268                 name = system->name;
1269
1270         ret = __ftrace_set_clr_event(dir->tr, NULL, name, NULL, val);
1271         if (ret)
1272                 goto out;
1273
1274         ret = cnt;
1275
1276 out:
1277         *ppos += cnt;
1278
1279         return ret;
1280 }
1281
1282 enum {
1283         FORMAT_HEADER           = 1,
1284         FORMAT_FIELD_SEPERATOR  = 2,
1285         FORMAT_PRINTFMT         = 3,
1286 };
1287
1288 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
1289 {
1290         struct trace_event_call *call = event_file_data(m->private);
1291         struct list_head *common_head = &ftrace_common_fields;
1292         struct list_head *head = trace_get_fields(call);
1293         struct list_head *node = v;
1294
1295         (*pos)++;
1296
1297         switch ((unsigned long)v) {
1298         case FORMAT_HEADER:
1299                 node = common_head;
1300                 break;
1301
1302         case FORMAT_FIELD_SEPERATOR:
1303                 node = head;
1304                 break;
1305
1306         case FORMAT_PRINTFMT:
1307                 /* all done */
1308                 return NULL;
1309         }
1310
1311         node = node->prev;
1312         if (node == common_head)
1313                 return (void *)FORMAT_FIELD_SEPERATOR;
1314         else if (node == head)
1315                 return (void *)FORMAT_PRINTFMT;
1316         else
1317                 return node;
1318 }
1319
1320 static int f_show(struct seq_file *m, void *v)
1321 {
1322         struct trace_event_call *call = event_file_data(m->private);
1323         struct ftrace_event_field *field;
1324         const char *array_descriptor;
1325
1326         switch ((unsigned long)v) {
1327         case FORMAT_HEADER:
1328                 seq_printf(m, "name: %s\n", trace_event_name(call));
1329                 seq_printf(m, "ID: %d\n", call->event.type);
1330                 seq_puts(m, "format:\n");
1331                 return 0;
1332
1333         case FORMAT_FIELD_SEPERATOR:
1334                 seq_putc(m, '\n');
1335                 return 0;
1336
1337         case FORMAT_PRINTFMT:
1338                 seq_printf(m, "\nprint fmt: %s\n",
1339                            call->print_fmt);
1340                 return 0;
1341         }
1342
1343         field = list_entry(v, struct ftrace_event_field, link);
1344         /*
1345          * Smartly shows the array type(except dynamic array).
1346          * Normal:
1347          *      field:TYPE VAR
1348          * If TYPE := TYPE[LEN], it is shown:
1349          *      field:TYPE VAR[LEN]
1350          */
1351         array_descriptor = strchr(field->type, '[');
1352
1353         if (str_has_prefix(field->type, "__data_loc"))
1354                 array_descriptor = NULL;
1355
1356         if (!array_descriptor)
1357                 seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1358                            field->type, field->name, field->offset,
1359                            field->size, !!field->is_signed);
1360         else
1361                 seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
1362                            (int)(array_descriptor - field->type),
1363                            field->type, field->name,
1364                            array_descriptor, field->offset,
1365                            field->size, !!field->is_signed);
1366
1367         return 0;
1368 }
1369
1370 static void *f_start(struct seq_file *m, loff_t *pos)
1371 {
1372         void *p = (void *)FORMAT_HEADER;
1373         loff_t l = 0;
1374
1375         /* ->stop() is called even if ->start() fails */
1376         mutex_lock(&event_mutex);
1377         if (!event_file_data(m->private))
1378                 return ERR_PTR(-ENODEV);
1379
1380         while (l < *pos && p)
1381                 p = f_next(m, p, &l);
1382
1383         return p;
1384 }
1385
1386 static void f_stop(struct seq_file *m, void *p)
1387 {
1388         mutex_unlock(&event_mutex);
1389 }
1390
1391 static const struct seq_operations trace_format_seq_ops = {
1392         .start          = f_start,
1393         .next           = f_next,
1394         .stop           = f_stop,
1395         .show           = f_show,
1396 };
1397
1398 static int trace_format_open(struct inode *inode, struct file *file)
1399 {
1400         struct seq_file *m;
1401         int ret;
1402
1403         /* Do we want to hide event format files on tracefs lockdown? */
1404
1405         ret = seq_open(file, &trace_format_seq_ops);
1406         if (ret < 0)
1407                 return ret;
1408
1409         m = file->private_data;
1410         m->private = file;
1411
1412         return 0;
1413 }
1414
1415 static ssize_t
1416 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1417 {
1418         int id = (long)event_file_data(filp);
1419         char buf[32];
1420         int len;
1421
1422         if (unlikely(!id))
1423                 return -ENODEV;
1424
1425         len = sprintf(buf, "%d\n", id);
1426
1427         return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
1428 }
1429
1430 static ssize_t
1431 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1432                   loff_t *ppos)
1433 {
1434         struct trace_event_file *file;
1435         struct trace_seq *s;
1436         int r = -ENODEV;
1437
1438         if (*ppos)
1439                 return 0;
1440
1441         s = kmalloc(sizeof(*s), GFP_KERNEL);
1442
1443         if (!s)
1444                 return -ENOMEM;
1445
1446         trace_seq_init(s);
1447
1448         mutex_lock(&event_mutex);
1449         file = event_file_data(filp);
1450         if (file)
1451                 print_event_filter(file, s);
1452         mutex_unlock(&event_mutex);
1453
1454         if (file)
1455                 r = simple_read_from_buffer(ubuf, cnt, ppos,
1456                                             s->buffer, trace_seq_used(s));
1457
1458         kfree(s);
1459
1460         return r;
1461 }
1462
1463 static ssize_t
1464 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1465                    loff_t *ppos)
1466 {
1467         struct trace_event_file *file;
1468         char *buf;
1469         int err = -ENODEV;
1470
1471         if (cnt >= PAGE_SIZE)
1472                 return -EINVAL;
1473
1474         buf = memdup_user_nul(ubuf, cnt);
1475         if (IS_ERR(buf))
1476                 return PTR_ERR(buf);
1477
1478         mutex_lock(&event_mutex);
1479         file = event_file_data(filp);
1480         if (file)
1481                 err = apply_event_filter(file, buf);
1482         mutex_unlock(&event_mutex);
1483
1484         kfree(buf);
1485         if (err < 0)
1486                 return err;
1487
1488         *ppos += cnt;
1489
1490         return cnt;
1491 }
1492
1493 static LIST_HEAD(event_subsystems);
1494
1495 static int subsystem_open(struct inode *inode, struct file *filp)
1496 {
1497         struct event_subsystem *system = NULL;
1498         struct trace_subsystem_dir *dir = NULL; /* Initialize for gcc */
1499         struct trace_array *tr;
1500         int ret;
1501
1502         if (tracing_is_disabled())
1503                 return -ENODEV;
1504
1505         /* Make sure the system still exists */
1506         mutex_lock(&event_mutex);
1507         mutex_lock(&trace_types_lock);
1508         list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1509                 list_for_each_entry(dir, &tr->systems, list) {
1510                         if (dir == inode->i_private) {
1511                                 /* Don't open systems with no events */
1512                                 if (dir->nr_events) {
1513                                         __get_system_dir(dir);
1514                                         system = dir->subsystem;
1515                                 }
1516                                 goto exit_loop;
1517                         }
1518                 }
1519         }
1520  exit_loop:
1521         mutex_unlock(&trace_types_lock);
1522         mutex_unlock(&event_mutex);
1523
1524         if (!system)
1525                 return -ENODEV;
1526
1527         /* Some versions of gcc think dir can be uninitialized here */
1528         WARN_ON(!dir);
1529
1530         /* Still need to increment the ref count of the system */
1531         if (trace_array_get(tr) < 0) {
1532                 put_system(dir);
1533                 return -ENODEV;
1534         }
1535
1536         ret = tracing_open_generic(inode, filp);
1537         if (ret < 0) {
1538                 trace_array_put(tr);
1539                 put_system(dir);
1540         }
1541
1542         return ret;
1543 }
1544
1545 static int system_tr_open(struct inode *inode, struct file *filp)
1546 {
1547         struct trace_subsystem_dir *dir;
1548         struct trace_array *tr = inode->i_private;
1549         int ret;
1550
1551         /* Make a temporary dir that has no system but points to tr */
1552         dir = kzalloc(sizeof(*dir), GFP_KERNEL);
1553         if (!dir)
1554                 return -ENOMEM;
1555
1556         ret = tracing_open_generic_tr(inode, filp);
1557         if (ret < 0) {
1558                 kfree(dir);
1559                 return ret;
1560         }
1561         dir->tr = tr;
1562         filp->private_data = dir;
1563
1564         return 0;
1565 }
1566
1567 static int subsystem_release(struct inode *inode, struct file *file)
1568 {
1569         struct trace_subsystem_dir *dir = file->private_data;
1570
1571         trace_array_put(dir->tr);
1572
1573         /*
1574          * If dir->subsystem is NULL, then this is a temporary
1575          * descriptor that was made for a trace_array to enable
1576          * all subsystems.
1577          */
1578         if (dir->subsystem)
1579                 put_system(dir);
1580         else
1581                 kfree(dir);
1582
1583         return 0;
1584 }
1585
1586 static ssize_t
1587 subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
1588                       loff_t *ppos)
1589 {
1590         struct trace_subsystem_dir *dir = filp->private_data;
1591         struct event_subsystem *system = dir->subsystem;
1592         struct trace_seq *s;
1593         int r;
1594
1595         if (*ppos)
1596                 return 0;
1597
1598         s = kmalloc(sizeof(*s), GFP_KERNEL);
1599         if (!s)
1600                 return -ENOMEM;
1601
1602         trace_seq_init(s);
1603
1604         print_subsystem_event_filter(system, s);
1605         r = simple_read_from_buffer(ubuf, cnt, ppos,
1606                                     s->buffer, trace_seq_used(s));
1607
1608         kfree(s);
1609
1610         return r;
1611 }
1612
1613 static ssize_t
1614 subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
1615                        loff_t *ppos)
1616 {
1617         struct trace_subsystem_dir *dir = filp->private_data;
1618         char *buf;
1619         int err;
1620
1621         if (cnt >= PAGE_SIZE)
1622                 return -EINVAL;
1623
1624         buf = memdup_user_nul(ubuf, cnt);
1625         if (IS_ERR(buf))
1626                 return PTR_ERR(buf);
1627
1628         err = apply_subsystem_event_filter(dir, buf);
1629         kfree(buf);
1630         if (err < 0)
1631                 return err;
1632
1633         *ppos += cnt;
1634
1635         return cnt;
1636 }
1637
1638 static ssize_t
1639 show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
1640 {
1641         int (*func)(struct trace_seq *s) = filp->private_data;
1642         struct trace_seq *s;
1643         int r;
1644
1645         if (*ppos)
1646                 return 0;
1647
1648         s = kmalloc(sizeof(*s), GFP_KERNEL);
1649         if (!s)
1650                 return -ENOMEM;
1651
1652         trace_seq_init(s);
1653
1654         func(s);
1655         r = simple_read_from_buffer(ubuf, cnt, ppos,
1656                                     s->buffer, trace_seq_used(s));
1657
1658         kfree(s);
1659
1660         return r;
1661 }
1662
1663 static void ignore_task_cpu(void *data)
1664 {
1665         struct trace_array *tr = data;
1666         struct trace_pid_list *pid_list;
1667         struct trace_pid_list *no_pid_list;
1668
1669         /*
1670          * This function is called by on_each_cpu() while the
1671          * event_mutex is held.
1672          */
1673         pid_list = rcu_dereference_protected(tr->filtered_pids,
1674                                              mutex_is_locked(&event_mutex));
1675         no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
1676                                              mutex_is_locked(&event_mutex));
1677
1678         this_cpu_write(tr->array_buffer.data->ignore_pid,
1679                        trace_ignore_this_task(pid_list, no_pid_list, current));
1680 }
1681
1682 static void register_pid_events(struct trace_array *tr)
1683 {
1684         /*
1685          * Register a probe that is called before all other probes
1686          * to set ignore_pid if next or prev do not match.
1687          * Register a probe this is called after all other probes
1688          * to only keep ignore_pid set if next pid matches.
1689          */
1690         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
1691                                          tr, INT_MAX);
1692         register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
1693                                          tr, 0);
1694
1695         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
1696                                          tr, INT_MAX);
1697         register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
1698                                          tr, 0);
1699
1700         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
1701                                              tr, INT_MAX);
1702         register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
1703                                              tr, 0);
1704
1705         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
1706                                          tr, INT_MAX);
1707         register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
1708                                          tr, 0);
1709 }
1710
1711 static ssize_t
1712 event_pid_write(struct file *filp, const char __user *ubuf,
1713                 size_t cnt, loff_t *ppos, int type)
1714 {
1715         struct seq_file *m = filp->private_data;
1716         struct trace_array *tr = m->private;
1717         struct trace_pid_list *filtered_pids = NULL;
1718         struct trace_pid_list *other_pids = NULL;
1719         struct trace_pid_list *pid_list;
1720         struct trace_event_file *file;
1721         ssize_t ret;
1722
1723         if (!cnt)
1724                 return 0;
1725
1726         ret = tracing_update_buffers();
1727         if (ret < 0)
1728                 return ret;
1729
1730         mutex_lock(&event_mutex);
1731
1732         if (type == TRACE_PIDS) {
1733                 filtered_pids = rcu_dereference_protected(tr->filtered_pids,
1734                                                           lockdep_is_held(&event_mutex));
1735                 other_pids = rcu_dereference_protected(tr->filtered_no_pids,
1736                                                           lockdep_is_held(&event_mutex));
1737         } else {
1738                 filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
1739                                                           lockdep_is_held(&event_mutex));
1740                 other_pids = rcu_dereference_protected(tr->filtered_pids,
1741                                                           lockdep_is_held(&event_mutex));
1742         }
1743
1744         ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
1745         if (ret < 0)
1746                 goto out;
1747
1748         if (type == TRACE_PIDS)
1749                 rcu_assign_pointer(tr->filtered_pids, pid_list);
1750         else
1751                 rcu_assign_pointer(tr->filtered_no_pids, pid_list);
1752
1753         list_for_each_entry(file, &tr->events, list) {
1754                 set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
1755         }
1756
1757         if (filtered_pids) {
1758                 tracepoint_synchronize_unregister();
1759                 trace_free_pid_list(filtered_pids);
1760         } else if (pid_list && !other_pids) {
1761                 register_pid_events(tr);
1762         }
1763
1764         /*
1765          * Ignoring of pids is done at task switch. But we have to
1766          * check for those tasks that are currently running.
1767          * Always do this in case a pid was appended or removed.
1768          */
1769         on_each_cpu(ignore_task_cpu, tr, 1);
1770
1771  out:
1772         mutex_unlock(&event_mutex);
1773
1774         if (ret > 0)
1775                 *ppos += ret;
1776
1777         return ret;
1778 }
1779
1780 static ssize_t
1781 ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
1782                        size_t cnt, loff_t *ppos)
1783 {
1784         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
1785 }
1786
1787 static ssize_t
1788 ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
1789                         size_t cnt, loff_t *ppos)
1790 {
1791         return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
1792 }
1793
1794 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
1795 static int ftrace_event_set_open(struct inode *inode, struct file *file);
1796 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
1797 static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
1798 static int ftrace_event_release(struct inode *inode, struct file *file);
1799
1800 static const struct seq_operations show_event_seq_ops = {
1801         .start = t_start,
1802         .next = t_next,
1803         .show = t_show,
1804         .stop = t_stop,
1805 };
1806
1807 static const struct seq_operations show_set_event_seq_ops = {
1808         .start = s_start,
1809         .next = s_next,
1810         .show = t_show,
1811         .stop = t_stop,
1812 };
1813
1814 static const struct seq_operations show_set_pid_seq_ops = {
1815         .start = p_start,
1816         .next = p_next,
1817         .show = trace_pid_show,
1818         .stop = p_stop,
1819 };
1820
1821 static const struct seq_operations show_set_no_pid_seq_ops = {
1822         .start = np_start,
1823         .next = np_next,
1824         .show = trace_pid_show,
1825         .stop = p_stop,
1826 };
1827
1828 static const struct file_operations ftrace_avail_fops = {
1829         .open = ftrace_event_avail_open,
1830         .read = seq_read,
1831         .llseek = seq_lseek,
1832         .release = seq_release,
1833 };
1834
1835 static const struct file_operations ftrace_set_event_fops = {
1836         .open = ftrace_event_set_open,
1837         .read = seq_read,
1838         .write = ftrace_event_write,
1839         .llseek = seq_lseek,
1840         .release = ftrace_event_release,
1841 };
1842
1843 static const struct file_operations ftrace_set_event_pid_fops = {
1844         .open = ftrace_event_set_pid_open,
1845         .read = seq_read,
1846         .write = ftrace_event_pid_write,
1847         .llseek = seq_lseek,
1848         .release = ftrace_event_release,
1849 };
1850
1851 static const struct file_operations ftrace_set_event_notrace_pid_fops = {
1852         .open = ftrace_event_set_npid_open,
1853         .read = seq_read,
1854         .write = ftrace_event_npid_write,
1855         .llseek = seq_lseek,
1856         .release = ftrace_event_release,
1857 };
1858
1859 static const struct file_operations ftrace_enable_fops = {
1860         .open = tracing_open_generic,
1861         .read = event_enable_read,
1862         .write = event_enable_write,
1863         .llseek = default_llseek,
1864 };
1865
1866 static const struct file_operations ftrace_event_format_fops = {
1867         .open = trace_format_open,
1868         .read = seq_read,
1869         .llseek = seq_lseek,
1870         .release = seq_release,
1871 };
1872
1873 static const struct file_operations ftrace_event_id_fops = {
1874         .read = event_id_read,
1875         .llseek = default_llseek,
1876 };
1877
1878 static const struct file_operations ftrace_event_filter_fops = {
1879         .open = tracing_open_generic,
1880         .read = event_filter_read,
1881         .write = event_filter_write,
1882         .llseek = default_llseek,
1883 };
1884
1885 static const struct file_operations ftrace_subsystem_filter_fops = {
1886         .open = subsystem_open,
1887         .read = subsystem_filter_read,
1888         .write = subsystem_filter_write,
1889         .llseek = default_llseek,
1890         .release = subsystem_release,
1891 };
1892
1893 static const struct file_operations ftrace_system_enable_fops = {
1894         .open = subsystem_open,
1895         .read = system_enable_read,
1896         .write = system_enable_write,
1897         .llseek = default_llseek,
1898         .release = subsystem_release,
1899 };
1900
1901 static const struct file_operations ftrace_tr_enable_fops = {
1902         .open = system_tr_open,
1903         .read = system_enable_read,
1904         .write = system_enable_write,
1905         .llseek = default_llseek,
1906         .release = subsystem_release,
1907 };
1908
1909 static const struct file_operations ftrace_show_header_fops = {
1910         .open = tracing_open_generic,
1911         .read = show_header,
1912         .llseek = default_llseek,
1913 };
1914
1915 static int
1916 ftrace_event_open(struct inode *inode, struct file *file,
1917                   const struct seq_operations *seq_ops)
1918 {
1919         struct seq_file *m;
1920         int ret;
1921
1922         ret = security_locked_down(LOCKDOWN_TRACEFS);
1923         if (ret)
1924                 return ret;
1925
1926         ret = seq_open(file, seq_ops);
1927         if (ret < 0)
1928                 return ret;
1929         m = file->private_data;
1930         /* copy tr over to seq ops */
1931         m->private = inode->i_private;
1932
1933         return ret;
1934 }
1935
1936 static int ftrace_event_release(struct inode *inode, struct file *file)
1937 {
1938         struct trace_array *tr = inode->i_private;
1939
1940         trace_array_put(tr);
1941
1942         return seq_release(inode, file);
1943 }
1944
1945 static int
1946 ftrace_event_avail_open(struct inode *inode, struct file *file)
1947 {
1948         const struct seq_operations *seq_ops = &show_event_seq_ops;
1949
1950         /* Checks for tracefs lockdown */
1951         return ftrace_event_open(inode, file, seq_ops);
1952 }
1953
1954 static int
1955 ftrace_event_set_open(struct inode *inode, struct file *file)
1956 {
1957         const struct seq_operations *seq_ops = &show_set_event_seq_ops;
1958         struct trace_array *tr = inode->i_private;
1959         int ret;
1960
1961         ret = tracing_check_open_get_tr(tr);
1962         if (ret)
1963                 return ret;
1964
1965         if ((file->f_mode & FMODE_WRITE) &&
1966             (file->f_flags & O_TRUNC))
1967                 ftrace_clear_events(tr);
1968
1969         ret = ftrace_event_open(inode, file, seq_ops);
1970         if (ret < 0)
1971                 trace_array_put(tr);
1972         return ret;
1973 }
1974
1975 static int
1976 ftrace_event_set_pid_open(struct inode *inode, struct file *file)
1977 {
1978         const struct seq_operations *seq_ops = &show_set_pid_seq_ops;
1979         struct trace_array *tr = inode->i_private;
1980         int ret;
1981
1982         ret = tracing_check_open_get_tr(tr);
1983         if (ret)
1984                 return ret;
1985
1986         if ((file->f_mode & FMODE_WRITE) &&
1987             (file->f_flags & O_TRUNC))
1988                 ftrace_clear_event_pids(tr, TRACE_PIDS);
1989
1990         ret = ftrace_event_open(inode, file, seq_ops);
1991         if (ret < 0)
1992                 trace_array_put(tr);
1993         return ret;
1994 }
1995
1996 static int
1997 ftrace_event_set_npid_open(struct inode *inode, struct file *file)
1998 {
1999         const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
2000         struct trace_array *tr = inode->i_private;
2001         int ret;
2002
2003         ret = tracing_check_open_get_tr(tr);
2004         if (ret)
2005                 return ret;
2006
2007         if ((file->f_mode & FMODE_WRITE) &&
2008             (file->f_flags & O_TRUNC))
2009                 ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
2010
2011         ret = ftrace_event_open(inode, file, seq_ops);
2012         if (ret < 0)
2013                 trace_array_put(tr);
2014         return ret;
2015 }
2016
2017 static struct event_subsystem *
2018 create_new_subsystem(const char *name)
2019 {
2020         struct event_subsystem *system;
2021
2022         /* need to create new entry */
2023         system = kmalloc(sizeof(*system), GFP_KERNEL);
2024         if (!system)
2025                 return NULL;
2026
2027         system->ref_count = 1;
2028
2029         /* Only allocate if dynamic (kprobes and modules) */
2030         system->name = kstrdup_const(name, GFP_KERNEL);
2031         if (!system->name)
2032                 goto out_free;
2033
2034         system->filter = NULL;
2035
2036         system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
2037         if (!system->filter)
2038                 goto out_free;
2039
2040         list_add(&system->list, &event_subsystems);
2041
2042         return system;
2043
2044  out_free:
2045         kfree_const(system->name);
2046         kfree(system);
2047         return NULL;
2048 }
2049
2050 static struct dentry *
2051 event_subsystem_dir(struct trace_array *tr, const char *name,
2052                     struct trace_event_file *file, struct dentry *parent)
2053 {
2054         struct trace_subsystem_dir *dir;
2055         struct event_subsystem *system;
2056         struct dentry *entry;
2057
2058         /* First see if we did not already create this dir */
2059         list_for_each_entry(dir, &tr->systems, list) {
2060                 system = dir->subsystem;
2061                 if (strcmp(system->name, name) == 0) {
2062                         dir->nr_events++;
2063                         file->system = dir;
2064                         return dir->entry;
2065                 }
2066         }
2067
2068         /* Now see if the system itself exists. */
2069         list_for_each_entry(system, &event_subsystems, list) {
2070                 if (strcmp(system->name, name) == 0)
2071                         break;
2072         }
2073         /* Reset system variable when not found */
2074         if (&system->list == &event_subsystems)
2075                 system = NULL;
2076
2077         dir = kmalloc(sizeof(*dir), GFP_KERNEL);
2078         if (!dir)
2079                 goto out_fail;
2080
2081         if (!system) {
2082                 system = create_new_subsystem(name);
2083                 if (!system)
2084                         goto out_free;
2085         } else
2086                 __get_system(system);
2087
2088         dir->entry = tracefs_create_dir(name, parent);
2089         if (!dir->entry) {
2090                 pr_warn("Failed to create system directory %s\n", name);
2091                 __put_system(system);
2092                 goto out_free;
2093         }
2094
2095         dir->tr = tr;
2096         dir->ref_count = 1;
2097         dir->nr_events = 1;
2098         dir->subsystem = system;
2099         file->system = dir;
2100
2101         /* the ftrace system is special, do not create enable or filter files */
2102         if (strcmp(name, "ftrace") != 0) {
2103
2104                 entry = tracefs_create_file("filter", 0644, dir->entry, dir,
2105                                             &ftrace_subsystem_filter_fops);
2106                 if (!entry) {
2107                         kfree(system->filter);
2108                         system->filter = NULL;
2109                         pr_warn("Could not create tracefs '%s/filter' entry\n", name);
2110                 }
2111
2112                 trace_create_file("enable", 0644, dir->entry, dir,
2113                                   &ftrace_system_enable_fops);
2114         }
2115
2116         list_add(&dir->list, &tr->systems);
2117
2118         return dir->entry;
2119
2120  out_free:
2121         kfree(dir);
2122  out_fail:
2123         /* Only print this message if failed on memory allocation */
2124         if (!dir || !system)
2125                 pr_warn("No memory to create event subsystem %s\n", name);
2126         return NULL;
2127 }
2128
2129 static int
2130 event_define_fields(struct trace_event_call *call)
2131 {
2132         struct list_head *head;
2133         int ret = 0;
2134
2135         /*
2136          * Other events may have the same class. Only update
2137          * the fields if they are not already defined.
2138          */
2139         head = trace_get_fields(call);
2140         if (list_empty(head)) {
2141                 struct trace_event_fields *field = call->class->fields_array;
2142                 unsigned int offset = sizeof(struct trace_entry);
2143
2144                 for (; field->type; field++) {
2145                         if (field->type == TRACE_FUNCTION_TYPE) {
2146                                 field->define_fields(call);
2147                                 break;
2148                         }
2149
2150                         offset = ALIGN(offset, field->align);
2151                         ret = trace_define_field(call, field->type, field->name,
2152                                                  offset, field->size,
2153                                                  field->is_signed, field->filter_type);
2154                         if (WARN_ON_ONCE(ret)) {
2155                                 pr_err("error code is %d\n", ret);
2156                                 break;
2157                         }
2158
2159                         offset += field->size;
2160                 }
2161         }
2162
2163         return ret;
2164 }
2165
2166 static int
2167 event_create_dir(struct dentry *parent, struct trace_event_file *file)
2168 {
2169         struct trace_event_call *call = file->event_call;
2170         struct trace_array *tr = file->tr;
2171         struct dentry *d_events;
2172         const char *name;
2173         int ret;
2174
2175         /*
2176          * If the trace point header did not define TRACE_SYSTEM
2177          * then the system would be called "TRACE_SYSTEM".
2178          */
2179         if (strcmp(call->class->system, TRACE_SYSTEM) != 0) {
2180                 d_events = event_subsystem_dir(tr, call->class->system, file, parent);
2181                 if (!d_events)
2182                         return -ENOMEM;
2183         } else
2184                 d_events = parent;
2185
2186         name = trace_event_name(call);
2187         file->dir = tracefs_create_dir(name, d_events);
2188         if (!file->dir) {
2189                 pr_warn("Could not create tracefs '%s' directory\n", name);
2190                 return -1;
2191         }
2192
2193         if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
2194                 trace_create_file("enable", 0644, file->dir, file,
2195                                   &ftrace_enable_fops);
2196
2197 #ifdef CONFIG_PERF_EVENTS
2198         if (call->event.type && call->class->reg)
2199                 trace_create_file("id", 0444, file->dir,
2200                                   (void *)(long)call->event.type,
2201                                   &ftrace_event_id_fops);
2202 #endif
2203
2204         ret = event_define_fields(call);
2205         if (ret < 0) {
2206                 pr_warn("Could not initialize trace point events/%s\n", name);
2207                 return ret;
2208         }
2209
2210         /*
2211          * Only event directories that can be enabled should have
2212          * triggers or filters.
2213          */
2214         if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
2215                 trace_create_file("filter", 0644, file->dir, file,
2216                                   &ftrace_event_filter_fops);
2217
2218                 trace_create_file("trigger", 0644, file->dir, file,
2219                                   &event_trigger_fops);
2220         }
2221
2222 #ifdef CONFIG_HIST_TRIGGERS
2223         trace_create_file("hist", 0444, file->dir, file,
2224                           &event_hist_fops);
2225 #endif
2226 #ifdef CONFIG_HIST_TRIGGERS_DEBUG
2227         trace_create_file("hist_debug", 0444, file->dir, file,
2228                           &event_hist_debug_fops);
2229 #endif
2230         trace_create_file("format", 0444, file->dir, call,
2231                           &ftrace_event_format_fops);
2232
2233 #ifdef CONFIG_TRACE_EVENT_INJECT
2234         if (call->event.type && call->class->reg)
2235                 trace_create_file("inject", 0200, file->dir, file,
2236                                   &event_inject_fops);
2237 #endif
2238
2239         return 0;
2240 }
2241
2242 static void remove_event_from_tracers(struct trace_event_call *call)
2243 {
2244         struct trace_event_file *file;
2245         struct trace_array *tr;
2246
2247         do_for_each_event_file_safe(tr, file) {
2248                 if (file->event_call != call)
2249                         continue;
2250
2251                 remove_event_file_dir(file);
2252                 /*
2253                  * The do_for_each_event_file_safe() is
2254                  * a double loop. After finding the call for this
2255                  * trace_array, we use break to jump to the next
2256                  * trace_array.
2257                  */
2258                 break;
2259         } while_for_each_event_file();
2260 }
2261
2262 static void event_remove(struct trace_event_call *call)
2263 {
2264         struct trace_array *tr;
2265         struct trace_event_file *file;
2266
2267         do_for_each_event_file(tr, file) {
2268                 if (file->event_call != call)
2269                         continue;
2270
2271                 if (file->flags & EVENT_FILE_FL_WAS_ENABLED)
2272                         tr->clear_trace = true;
2273
2274                 ftrace_event_enable_disable(file, 0);
2275                 /*
2276                  * The do_for_each_event_file() is
2277                  * a double loop. After finding the call for this
2278                  * trace_array, we use break to jump to the next
2279                  * trace_array.
2280                  */
2281                 break;
2282         } while_for_each_event_file();
2283
2284         if (call->event.funcs)
2285                 __unregister_trace_event(&call->event);
2286         remove_event_from_tracers(call);
2287         list_del(&call->list);
2288 }
2289
2290 static int event_init(struct trace_event_call *call)
2291 {
2292         int ret = 0;
2293         const char *name;
2294
2295         name = trace_event_name(call);
2296         if (WARN_ON(!name))
2297                 return -EINVAL;
2298
2299         if (call->class->raw_init) {
2300                 ret = call->class->raw_init(call);
2301                 if (ret < 0 && ret != -ENOSYS)
2302                         pr_warn("Could not initialize trace events/%s\n", name);
2303         }
2304
2305         return ret;
2306 }
2307
2308 static int
2309 __register_event(struct trace_event_call *call, struct module *mod)
2310 {
2311         int ret;
2312
2313         ret = event_init(call);
2314         if (ret < 0)
2315                 return ret;
2316
2317         list_add(&call->list, &ftrace_events);
2318         call->mod = mod;
2319
2320         return 0;
2321 }
2322
2323 static char *eval_replace(char *ptr, struct trace_eval_map *map, int len)
2324 {
2325         int rlen;
2326         int elen;
2327
2328         /* Find the length of the eval value as a string */
2329         elen = snprintf(ptr, 0, "%ld", map->eval_value);
2330         /* Make sure there's enough room to replace the string with the value */
2331         if (len < elen)
2332                 return NULL;
2333
2334         snprintf(ptr, elen + 1, "%ld", map->eval_value);
2335
2336         /* Get the rest of the string of ptr */
2337         rlen = strlen(ptr + len);
2338         memmove(ptr + elen, ptr + len, rlen);
2339         /* Make sure we end the new string */
2340         ptr[elen + rlen] = 0;
2341
2342         return ptr + elen;
2343 }
2344
2345 static void update_event_printk(struct trace_event_call *call,
2346                                 struct trace_eval_map *map)
2347 {
2348         char *ptr;
2349         int quote = 0;
2350         int len = strlen(map->eval_string);
2351
2352         for (ptr = call->print_fmt; *ptr; ptr++) {
2353                 if (*ptr == '\\') {
2354                         ptr++;
2355                         /* paranoid */
2356                         if (!*ptr)
2357                                 break;
2358                         continue;
2359                 }
2360                 if (*ptr == '"') {
2361                         quote ^= 1;
2362                         continue;
2363                 }
2364                 if (quote)
2365                         continue;
2366                 if (isdigit(*ptr)) {
2367                         /* skip numbers */
2368                         do {
2369                                 ptr++;
2370                                 /* Check for alpha chars like ULL */
2371                         } while (isalnum(*ptr));
2372                         if (!*ptr)
2373                                 break;
2374                         /*
2375                          * A number must have some kind of delimiter after
2376                          * it, and we can ignore that too.
2377                          */
2378                         continue;
2379                 }
2380                 if (isalpha(*ptr) || *ptr == '_') {
2381                         if (strncmp(map->eval_string, ptr, len) == 0 &&
2382                             !isalnum(ptr[len]) && ptr[len] != '_') {
2383                                 ptr = eval_replace(ptr, map, len);
2384                                 /* enum/sizeof string smaller than value */
2385                                 if (WARN_ON_ONCE(!ptr))
2386                                         return;
2387                                 /*
2388                                  * No need to decrement here, as eval_replace()
2389                                  * returns the pointer to the character passed
2390                                  * the eval, and two evals can not be placed
2391                                  * back to back without something in between.
2392                                  * We can skip that something in between.
2393                                  */
2394                                 continue;
2395                         }
2396                 skip_more:
2397                         do {
2398                                 ptr++;
2399                         } while (isalnum(*ptr) || *ptr == '_');
2400                         if (!*ptr)
2401                                 break;
2402                         /*
2403                          * If what comes after this variable is a '.' or
2404                          * '->' then we can continue to ignore that string.
2405                          */
2406                         if (*ptr == '.' || (ptr[0] == '-' && ptr[1] == '>')) {
2407                                 ptr += *ptr == '.' ? 1 : 2;
2408                                 if (!*ptr)
2409                                         break;
2410                                 goto skip_more;
2411                         }
2412                         /*
2413                          * Once again, we can skip the delimiter that came
2414                          * after the string.
2415                          */
2416                         continue;
2417                 }
2418         }
2419 }
2420
2421 void trace_event_eval_update(struct trace_eval_map **map, int len)
2422 {
2423         struct trace_event_call *call, *p;
2424         const char *last_system = NULL;
2425         bool first = false;
2426         int last_i;
2427         int i;
2428
2429         down_write(&trace_event_sem);
2430         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2431                 /* events are usually grouped together with systems */
2432                 if (!last_system || call->class->system != last_system) {
2433                         first = true;
2434                         last_i = 0;
2435                         last_system = call->class->system;
2436                 }
2437
2438                 /*
2439                  * Since calls are grouped by systems, the likelyhood that the
2440                  * next call in the iteration belongs to the same system as the
2441                  * previous call is high. As an optimization, we skip searching
2442                  * for a map[] that matches the call's system if the last call
2443                  * was from the same system. That's what last_i is for. If the
2444                  * call has the same system as the previous call, then last_i
2445                  * will be the index of the first map[] that has a matching
2446                  * system.
2447                  */
2448                 for (i = last_i; i < len; i++) {
2449                         if (call->class->system == map[i]->system) {
2450                                 /* Save the first system if need be */
2451                                 if (first) {
2452                                         last_i = i;
2453                                         first = false;
2454                                 }
2455                                 update_event_printk(call, map[i]);
2456                         }
2457                 }
2458         }
2459         up_write(&trace_event_sem);
2460 }
2461
2462 static struct trace_event_file *
2463 trace_create_new_event(struct trace_event_call *call,
2464                        struct trace_array *tr)
2465 {
2466         struct trace_event_file *file;
2467
2468         file = kmem_cache_alloc(file_cachep, GFP_TRACE);
2469         if (!file)
2470                 return NULL;
2471
2472         file->event_call = call;
2473         file->tr = tr;
2474         atomic_set(&file->sm_ref, 0);
2475         atomic_set(&file->tm_ref, 0);
2476         INIT_LIST_HEAD(&file->triggers);
2477         list_add(&file->list, &tr->events);
2478
2479         return file;
2480 }
2481
2482 /* Add an event to a trace directory */
2483 static int
2484 __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr)
2485 {
2486         struct trace_event_file *file;
2487
2488         file = trace_create_new_event(call, tr);
2489         if (!file)
2490                 return -ENOMEM;
2491
2492         if (eventdir_initialized)
2493                 return event_create_dir(tr->event_dir, file);
2494         else
2495                 return event_define_fields(call);
2496 }
2497
2498 /*
2499  * Just create a decriptor for early init. A descriptor is required
2500  * for enabling events at boot. We want to enable events before
2501  * the filesystem is initialized.
2502  */
2503 static int
2504 __trace_early_add_new_event(struct trace_event_call *call,
2505                             struct trace_array *tr)
2506 {
2507         struct trace_event_file *file;
2508
2509         file = trace_create_new_event(call, tr);
2510         if (!file)
2511                 return -ENOMEM;
2512
2513         return event_define_fields(call);
2514 }
2515
2516 struct ftrace_module_file_ops;
2517 static void __add_event_to_tracers(struct trace_event_call *call);
2518
2519 /* Add an additional event_call dynamically */
2520 int trace_add_event_call(struct trace_event_call *call)
2521 {
2522         int ret;
2523         lockdep_assert_held(&event_mutex);
2524
2525         mutex_lock(&trace_types_lock);
2526
2527         ret = __register_event(call, NULL);
2528         if (ret >= 0)
2529                 __add_event_to_tracers(call);
2530
2531         mutex_unlock(&trace_types_lock);
2532         return ret;
2533 }
2534
2535 /*
2536  * Must be called under locking of trace_types_lock, event_mutex and
2537  * trace_event_sem.
2538  */
2539 static void __trace_remove_event_call(struct trace_event_call *call)
2540 {
2541         event_remove(call);
2542         trace_destroy_fields(call);
2543         free_event_filter(call->filter);
2544         call->filter = NULL;
2545 }
2546
2547 static int probe_remove_event_call(struct trace_event_call *call)
2548 {
2549         struct trace_array *tr;
2550         struct trace_event_file *file;
2551
2552 #ifdef CONFIG_PERF_EVENTS
2553         if (call->perf_refcount)
2554                 return -EBUSY;
2555 #endif
2556         do_for_each_event_file(tr, file) {
2557                 if (file->event_call != call)
2558                         continue;
2559                 /*
2560                  * We can't rely on ftrace_event_enable_disable(enable => 0)
2561                  * we are going to do, EVENT_FILE_FL_SOFT_MODE can suppress
2562                  * TRACE_REG_UNREGISTER.
2563                  */
2564                 if (file->flags & EVENT_FILE_FL_ENABLED)
2565                         return -EBUSY;
2566                 /*
2567                  * The do_for_each_event_file_safe() is
2568                  * a double loop. After finding the call for this
2569                  * trace_array, we use break to jump to the next
2570                  * trace_array.
2571                  */
2572                 break;
2573         } while_for_each_event_file();
2574
2575         __trace_remove_event_call(call);
2576
2577         return 0;
2578 }
2579
2580 /* Remove an event_call */
2581 int trace_remove_event_call(struct trace_event_call *call)
2582 {
2583         int ret;
2584
2585         lockdep_assert_held(&event_mutex);
2586
2587         mutex_lock(&trace_types_lock);
2588         down_write(&trace_event_sem);
2589         ret = probe_remove_event_call(call);
2590         up_write(&trace_event_sem);
2591         mutex_unlock(&trace_types_lock);
2592
2593         return ret;
2594 }
2595
2596 #define for_each_event(event, start, end)                       \
2597         for (event = start;                                     \
2598              (unsigned long)event < (unsigned long)end;         \
2599              event++)
2600
2601 #ifdef CONFIG_MODULES
2602
2603 static void trace_module_add_events(struct module *mod)
2604 {
2605         struct trace_event_call **call, **start, **end;
2606
2607         if (!mod->num_trace_events)
2608                 return;
2609
2610         /* Don't add infrastructure for mods without tracepoints */
2611         if (trace_module_has_bad_taint(mod)) {
2612                 pr_err("%s: module has bad taint, not creating trace events\n",
2613                        mod->name);
2614                 return;
2615         }
2616
2617         start = mod->trace_events;
2618         end = mod->trace_events + mod->num_trace_events;
2619
2620         for_each_event(call, start, end) {
2621                 __register_event(*call, mod);
2622                 __add_event_to_tracers(*call);
2623         }
2624 }
2625
2626 static void trace_module_remove_events(struct module *mod)
2627 {
2628         struct trace_event_call *call, *p;
2629
2630         down_write(&trace_event_sem);
2631         list_for_each_entry_safe(call, p, &ftrace_events, list) {
2632                 if (call->mod == mod)
2633                         __trace_remove_event_call(call);
2634         }
2635         up_write(&trace_event_sem);
2636
2637         /*
2638          * It is safest to reset the ring buffer if the module being unloaded
2639          * registered any events that were used. The only worry is if
2640          * a new module gets loaded, and takes on the same id as the events
2641          * of this module. When printing out the buffer, traced events left
2642          * over from this module may be passed to the new module events and
2643          * unexpected results may occur.
2644          */
2645         tracing_reset_all_online_cpus();
2646 }
2647
2648 static int trace_module_notify(struct notifier_block *self,
2649                                unsigned long val, void *data)
2650 {
2651         struct module *mod = data;
2652
2653         mutex_lock(&event_mutex);
2654         mutex_lock(&trace_types_lock);
2655         switch (val) {
2656         case MODULE_STATE_COMING:
2657                 trace_module_add_events(mod);
2658                 break;
2659         case MODULE_STATE_GOING:
2660                 trace_module_remove_events(mod);
2661                 break;
2662         }
2663         mutex_unlock(&trace_types_lock);
2664         mutex_unlock(&event_mutex);
2665
2666         return NOTIFY_OK;
2667 }
2668
2669 static struct notifier_block trace_module_nb = {
2670         .notifier_call = trace_module_notify,
2671         .priority = 1, /* higher than trace.c module notify */
2672 };
2673 #endif /* CONFIG_MODULES */
2674
2675 /* Create a new event directory structure for a trace directory. */
2676 static void
2677 __trace_add_event_dirs(struct trace_array *tr)
2678 {
2679         struct trace_event_call *call;
2680         int ret;
2681
2682         list_for_each_entry(call, &ftrace_events, list) {
2683                 ret = __trace_add_new_event(call, tr);
2684                 if (ret < 0)
2685                         pr_warn("Could not create directory for event %s\n",
2686                                 trace_event_name(call));
2687         }
2688 }
2689
2690 /* Returns any file that matches the system and event */
2691 struct trace_event_file *
2692 __find_event_file(struct trace_array *tr, const char *system, const char *event)
2693 {
2694         struct trace_event_file *file;
2695         struct trace_event_call *call;
2696         const char *name;
2697
2698         list_for_each_entry(file, &tr->events, list) {
2699
2700                 call = file->event_call;
2701                 name = trace_event_name(call);
2702
2703                 if (!name || !call->class)
2704                         continue;
2705
2706                 if (strcmp(event, name) == 0 &&
2707                     strcmp(system, call->class->system) == 0)
2708                         return file;
2709         }
2710         return NULL;
2711 }
2712
2713 /* Returns valid trace event files that match system and event */
2714 struct trace_event_file *
2715 find_event_file(struct trace_array *tr, const char *system, const char *event)
2716 {
2717         struct trace_event_file *file;
2718
2719         file = __find_event_file(tr, system, event);
2720         if (!file || !file->event_call->class->reg ||
2721             file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
2722                 return NULL;
2723
2724         return file;
2725 }
2726
2727 /**
2728  * trace_get_event_file - Find and return a trace event file
2729  * @instance: The name of the trace instance containing the event
2730  * @system: The name of the system containing the event
2731  * @event: The name of the event
2732  *
2733  * Return a trace event file given the trace instance name, trace
2734  * system, and trace event name.  If the instance name is NULL, it
2735  * refers to the top-level trace array.
2736  *
2737  * This function will look it up and return it if found, after calling
2738  * trace_array_get() to prevent the instance from going away, and
2739  * increment the event's module refcount to prevent it from being
2740  * removed.
2741  *
2742  * To release the file, call trace_put_event_file(), which will call
2743  * trace_array_put() and decrement the event's module refcount.
2744  *
2745  * Return: The trace event on success, ERR_PTR otherwise.
2746  */
2747 struct trace_event_file *trace_get_event_file(const char *instance,
2748                                               const char *system,
2749                                               const char *event)
2750 {
2751         struct trace_array *tr = top_trace_array();
2752         struct trace_event_file *file = NULL;
2753         int ret = -EINVAL;
2754
2755         if (instance) {
2756                 tr = trace_array_find_get(instance);
2757                 if (!tr)
2758                         return ERR_PTR(-ENOENT);
2759         } else {
2760                 ret = trace_array_get(tr);
2761                 if (ret)
2762                         return ERR_PTR(ret);
2763         }
2764
2765         mutex_lock(&event_mutex);
2766
2767         file = find_event_file(tr, system, event);
2768         if (!file) {
2769                 trace_array_put(tr);
2770                 ret = -EINVAL;
2771                 goto out;
2772         }
2773
2774         /* Don't let event modules unload while in use */
2775         ret = try_module_get(file->event_call->mod);
2776         if (!ret) {
2777                 trace_array_put(tr);
2778                 ret = -EBUSY;
2779                 goto out;
2780         }
2781
2782         ret = 0;
2783  out:
2784         mutex_unlock(&event_mutex);
2785
2786         if (ret)
2787                 file = ERR_PTR(ret);
2788
2789         return file;
2790 }
2791 EXPORT_SYMBOL_GPL(trace_get_event_file);
2792
2793 /**
2794  * trace_put_event_file - Release a file from trace_get_event_file()
2795  * @file: The trace event file
2796  *
2797  * If a file was retrieved using trace_get_event_file(), this should
2798  * be called when it's no longer needed.  It will cancel the previous
2799  * trace_array_get() called by that function, and decrement the
2800  * event's module refcount.
2801  */
2802 void trace_put_event_file(struct trace_event_file *file)
2803 {
2804         mutex_lock(&event_mutex);
2805         module_put(file->event_call->mod);
2806         mutex_unlock(&event_mutex);
2807
2808         trace_array_put(file->tr);
2809 }
2810 EXPORT_SYMBOL_GPL(trace_put_event_file);
2811
2812 #ifdef CONFIG_DYNAMIC_FTRACE
2813
2814 /* Avoid typos */
2815 #define ENABLE_EVENT_STR        "enable_event"
2816 #define DISABLE_EVENT_STR       "disable_event"
2817
2818 struct event_probe_data {
2819         struct trace_event_file *file;
2820         unsigned long                   count;
2821         int                             ref;
2822         bool                            enable;
2823 };
2824
2825 static void update_event_probe(struct event_probe_data *data)
2826 {
2827         if (data->enable)
2828                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2829         else
2830                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &data->file->flags);
2831 }
2832
2833 static void
2834 event_enable_probe(unsigned long ip, unsigned long parent_ip,
2835                    struct trace_array *tr, struct ftrace_probe_ops *ops,
2836                    void *data)
2837 {
2838         struct ftrace_func_mapper *mapper = data;
2839         struct event_probe_data *edata;
2840         void **pdata;
2841
2842         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2843         if (!pdata || !*pdata)
2844                 return;
2845
2846         edata = *pdata;
2847         update_event_probe(edata);
2848 }
2849
2850 static void
2851 event_enable_count_probe(unsigned long ip, unsigned long parent_ip,
2852                          struct trace_array *tr, struct ftrace_probe_ops *ops,
2853                          void *data)
2854 {
2855         struct ftrace_func_mapper *mapper = data;
2856         struct event_probe_data *edata;
2857         void **pdata;
2858
2859         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2860         if (!pdata || !*pdata)
2861                 return;
2862
2863         edata = *pdata;
2864
2865         if (!edata->count)
2866                 return;
2867
2868         /* Skip if the event is in a state we want to switch to */
2869         if (edata->enable == !(edata->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
2870                 return;
2871
2872         if (edata->count != -1)
2873                 (edata->count)--;
2874
2875         update_event_probe(edata);
2876 }
2877
2878 static int
2879 event_enable_print(struct seq_file *m, unsigned long ip,
2880                    struct ftrace_probe_ops *ops, void *data)
2881 {
2882         struct ftrace_func_mapper *mapper = data;
2883         struct event_probe_data *edata;
2884         void **pdata;
2885
2886         pdata = ftrace_func_mapper_find_ip(mapper, ip);
2887
2888         if (WARN_ON_ONCE(!pdata || !*pdata))
2889                 return 0;
2890
2891         edata = *pdata;
2892
2893         seq_printf(m, "%ps:", (void *)ip);
2894
2895         seq_printf(m, "%s:%s:%s",
2896                    edata->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
2897                    edata->file->event_call->class->system,
2898                    trace_event_name(edata->file->event_call));
2899
2900         if (edata->count == -1)
2901                 seq_puts(m, ":unlimited\n");
2902         else
2903                 seq_printf(m, ":count=%ld\n", edata->count);
2904
2905         return 0;
2906 }
2907
2908 static int
2909 event_enable_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
2910                   unsigned long ip, void *init_data, void **data)
2911 {
2912         struct ftrace_func_mapper *mapper = *data;
2913         struct event_probe_data *edata = init_data;
2914         int ret;
2915
2916         if (!mapper) {
2917                 mapper = allocate_ftrace_func_mapper();
2918                 if (!mapper)
2919                         return -ENODEV;
2920                 *data = mapper;
2921         }
2922
2923         ret = ftrace_func_mapper_add_ip(mapper, ip, edata);
2924         if (ret < 0)
2925                 return ret;
2926
2927         edata->ref++;
2928
2929         return 0;
2930 }
2931
2932 static int free_probe_data(void *data)
2933 {
2934         struct event_probe_data *edata = data;
2935
2936         edata->ref--;
2937         if (!edata->ref) {
2938                 /* Remove the SOFT_MODE flag */
2939                 __ftrace_event_enable_disable(edata->file, 0, 1);
2940                 module_put(edata->file->event_call->mod);
2941                 kfree(edata);
2942         }
2943         return 0;
2944 }
2945
2946 static void
2947 event_enable_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
2948                   unsigned long ip, void *data)
2949 {
2950         struct ftrace_func_mapper *mapper = data;
2951         struct event_probe_data *edata;
2952
2953         if (!ip) {
2954                 if (!mapper)
2955                         return;
2956                 free_ftrace_func_mapper(mapper, free_probe_data);
2957                 return;
2958         }
2959
2960         edata = ftrace_func_mapper_remove_ip(mapper, ip);
2961
2962         if (WARN_ON_ONCE(!edata))
2963                 return;
2964
2965         if (WARN_ON_ONCE(edata->ref <= 0))
2966                 return;
2967
2968         free_probe_data(edata);
2969 }
2970
2971 static struct ftrace_probe_ops event_enable_probe_ops = {
2972         .func                   = event_enable_probe,
2973         .print                  = event_enable_print,
2974         .init                   = event_enable_init,
2975         .free                   = event_enable_free,
2976 };
2977
2978 static struct ftrace_probe_ops event_enable_count_probe_ops = {
2979         .func                   = event_enable_count_probe,
2980         .print                  = event_enable_print,
2981         .init                   = event_enable_init,
2982         .free                   = event_enable_free,
2983 };
2984
2985 static struct ftrace_probe_ops event_disable_probe_ops = {
2986         .func                   = event_enable_probe,
2987         .print                  = event_enable_print,
2988         .init                   = event_enable_init,
2989         .free                   = event_enable_free,
2990 };
2991
2992 static struct ftrace_probe_ops event_disable_count_probe_ops = {
2993         .func                   = event_enable_count_probe,
2994         .print                  = event_enable_print,
2995         .init                   = event_enable_init,
2996         .free                   = event_enable_free,
2997 };
2998
2999 static int
3000 event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
3001                   char *glob, char *cmd, char *param, int enabled)
3002 {
3003         struct trace_event_file *file;
3004         struct ftrace_probe_ops *ops;
3005         struct event_probe_data *data;
3006         const char *system;
3007         const char *event;
3008         char *number;
3009         bool enable;
3010         int ret;
3011
3012         if (!tr)
3013                 return -ENODEV;
3014
3015         /* hash funcs only work with set_ftrace_filter */
3016         if (!enabled || !param)
3017                 return -EINVAL;
3018
3019         system = strsep(&param, ":");
3020         if (!param)
3021                 return -EINVAL;
3022
3023         event = strsep(&param, ":");
3024
3025         mutex_lock(&event_mutex);
3026
3027         ret = -EINVAL;
3028         file = find_event_file(tr, system, event);
3029         if (!file)
3030                 goto out;
3031
3032         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
3033
3034         if (enable)
3035                 ops = param ? &event_enable_count_probe_ops : &event_enable_probe_ops;
3036         else
3037                 ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
3038
3039         if (glob[0] == '!') {
3040                 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
3041                 goto out;
3042         }
3043
3044         ret = -ENOMEM;
3045
3046         data = kzalloc(sizeof(*data), GFP_KERNEL);
3047         if (!data)
3048                 goto out;
3049
3050         data->enable = enable;
3051         data->count = -1;
3052         data->file = file;
3053
3054         if (!param)
3055                 goto out_reg;
3056
3057         number = strsep(&param, ":");
3058
3059         ret = -EINVAL;
3060         if (!strlen(number))
3061                 goto out_free;
3062
3063         /*
3064          * We use the callback data field (which is a pointer)
3065          * as our counter.
3066          */
3067         ret = kstrtoul(number, 0, &data->count);
3068         if (ret)
3069                 goto out_free;
3070
3071  out_reg:
3072         /* Don't let event modules unload while probe registered */
3073         ret = try_module_get(file->event_call->mod);
3074         if (!ret) {
3075                 ret = -EBUSY;
3076                 goto out_free;
3077         }
3078
3079         ret = __ftrace_event_enable_disable(file, 1, 1);
3080         if (ret < 0)
3081                 goto out_put;
3082
3083         ret = register_ftrace_function_probe(glob, tr, ops, data);
3084         /*
3085          * The above returns on success the # of functions enabled,
3086          * but if it didn't find any functions it returns zero.
3087          * Consider no functions a failure too.
3088          */
3089         if (!ret) {
3090                 ret = -ENOENT;
3091                 goto out_disable;
3092         } else if (ret < 0)
3093                 goto out_disable;
3094         /* Just return zero, not the number of enabled functions */
3095         ret = 0;
3096  out:
3097         mutex_unlock(&event_mutex);
3098         return ret;
3099
3100  out_disable:
3101         __ftrace_event_enable_disable(file, 0, 1);
3102  out_put:
3103         module_put(file->event_call->mod);
3104  out_free:
3105         kfree(data);
3106         goto out;
3107 }
3108
3109 static struct ftrace_func_command event_enable_cmd = {
3110         .name                   = ENABLE_EVENT_STR,
3111         .func                   = event_enable_func,
3112 };
3113
3114 static struct ftrace_func_command event_disable_cmd = {
3115         .name                   = DISABLE_EVENT_STR,
3116         .func                   = event_enable_func,
3117 };
3118
3119 static __init int register_event_cmds(void)
3120 {
3121         int ret;
3122
3123         ret = register_ftrace_command(&event_enable_cmd);
3124         if (WARN_ON(ret < 0))
3125                 return ret;
3126         ret = register_ftrace_command(&event_disable_cmd);
3127         if (WARN_ON(ret < 0))
3128                 unregister_ftrace_command(&event_enable_cmd);
3129         return ret;
3130 }
3131 #else
3132 static inline int register_event_cmds(void) { return 0; }
3133 #endif /* CONFIG_DYNAMIC_FTRACE */
3134
3135 /*
3136  * The top level array and trace arrays created by boot-time tracing
3137  * have already had its trace_event_file descriptors created in order
3138  * to allow for early events to be recorded.
3139  * This function is called after the tracefs has been initialized,
3140  * and we now have to create the files associated to the events.
3141  */
3142 static void __trace_early_add_event_dirs(struct trace_array *tr)
3143 {
3144         struct trace_event_file *file;
3145         int ret;
3146
3147
3148         list_for_each_entry(file, &tr->events, list) {
3149                 ret = event_create_dir(tr->event_dir, file);
3150                 if (ret < 0)
3151                         pr_warn("Could not create directory for event %s\n",
3152                                 trace_event_name(file->event_call));
3153         }
3154 }
3155
3156 /*
3157  * For early boot up, the top trace array and the trace arrays created
3158  * by boot-time tracing require to have a list of events that can be
3159  * enabled. This must be done before the filesystem is set up in order
3160  * to allow events to be traced early.
3161  */
3162 void __trace_early_add_events(struct trace_array *tr)
3163 {
3164         struct trace_event_call *call;
3165         int ret;
3166
3167         list_for_each_entry(call, &ftrace_events, list) {
3168                 /* Early boot up should not have any modules loaded */
3169                 if (WARN_ON_ONCE(call->mod))
3170                         continue;
3171
3172                 ret = __trace_early_add_new_event(call, tr);
3173                 if (ret < 0)
3174                         pr_warn("Could not create early event %s\n",
3175                                 trace_event_name(call));
3176         }
3177 }
3178
3179 /* Remove the event directory structure for a trace directory. */
3180 static void
3181 __trace_remove_event_dirs(struct trace_array *tr)
3182 {
3183         struct trace_event_file *file, *next;
3184
3185         list_for_each_entry_safe(file, next, &tr->events, list)
3186                 remove_event_file_dir(file);
3187 }
3188
3189 static void __add_event_to_tracers(struct trace_event_call *call)
3190 {
3191         struct trace_array *tr;
3192
3193         list_for_each_entry(tr, &ftrace_trace_arrays, list)
3194                 __trace_add_new_event(call, tr);
3195 }
3196
3197 extern struct trace_event_call *__start_ftrace_events[];
3198 extern struct trace_event_call *__stop_ftrace_events[];
3199
3200 static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
3201
3202 static __init int setup_trace_event(char *str)
3203 {
3204         strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
3205         ring_buffer_expanded = true;
3206         disable_tracing_selftest("running event tracing");
3207
3208         return 1;
3209 }
3210 __setup("trace_event=", setup_trace_event);
3211
3212 /* Expects to have event_mutex held when called */
3213 static int
3214 create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
3215 {
3216         struct dentry *d_events;
3217         struct dentry *entry;
3218
3219         entry = tracefs_create_file("set_event", 0644, parent,
3220                                     tr, &ftrace_set_event_fops);
3221         if (!entry) {
3222                 pr_warn("Could not create tracefs 'set_event' entry\n");
3223                 return -ENOMEM;
3224         }
3225
3226         d_events = tracefs_create_dir("events", parent);
3227         if (!d_events) {
3228                 pr_warn("Could not create tracefs 'events' directory\n");
3229                 return -ENOMEM;
3230         }
3231
3232         entry = trace_create_file("enable", 0644, d_events,
3233                                   tr, &ftrace_tr_enable_fops);
3234         if (!entry) {
3235                 pr_warn("Could not create tracefs 'enable' entry\n");
3236                 return -ENOMEM;
3237         }
3238
3239         /* There are not as crucial, just warn if they are not created */
3240
3241         entry = tracefs_create_file("set_event_pid", 0644, parent,
3242                                     tr, &ftrace_set_event_pid_fops);
3243         if (!entry)
3244                 pr_warn("Could not create tracefs 'set_event_pid' entry\n");
3245
3246         entry = tracefs_create_file("set_event_notrace_pid", 0644, parent,
3247                                     tr, &ftrace_set_event_notrace_pid_fops);
3248         if (!entry)
3249                 pr_warn("Could not create tracefs 'set_event_notrace_pid' entry\n");
3250
3251         /* ring buffer internal formats */
3252         entry = trace_create_file("header_page", 0444, d_events,
3253                                   ring_buffer_print_page_header,
3254                                   &ftrace_show_header_fops);
3255         if (!entry)
3256                 pr_warn("Could not create tracefs 'header_page' entry\n");
3257
3258         entry = trace_create_file("header_event", 0444, d_events,
3259                                   ring_buffer_print_entry_header,
3260                                   &ftrace_show_header_fops);
3261         if (!entry)
3262                 pr_warn("Could not create tracefs 'header_event' entry\n");
3263
3264         tr->event_dir = d_events;
3265
3266         return 0;
3267 }
3268
3269 /**
3270  * event_trace_add_tracer - add a instance of a trace_array to events
3271  * @parent: The parent dentry to place the files/directories for events in
3272  * @tr: The trace array associated with these events
3273  *
3274  * When a new instance is created, it needs to set up its events
3275  * directory, as well as other files associated with events. It also
3276  * creates the event hierarchy in the @parent/events directory.
3277  *
3278  * Returns 0 on success.
3279  *
3280  * Must be called with event_mutex held.
3281  */
3282 int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
3283 {
3284         int ret;
3285
3286         lockdep_assert_held(&event_mutex);
3287
3288         ret = create_event_toplevel_files(parent, tr);
3289         if (ret)
3290                 goto out;
3291
3292         down_write(&trace_event_sem);
3293         /* If tr already has the event list, it is initialized in early boot. */
3294         if (unlikely(!list_empty(&tr->events)))
3295                 __trace_early_add_event_dirs(tr);
3296         else
3297                 __trace_add_event_dirs(tr);
3298         up_write(&trace_event_sem);
3299
3300  out:
3301         return ret;
3302 }
3303
3304 /*
3305  * The top trace array already had its file descriptors created.
3306  * Now the files themselves need to be created.
3307  */
3308 static __init int
3309 early_event_add_tracer(struct dentry *parent, struct trace_array *tr)
3310 {
3311         int ret;
3312
3313         mutex_lock(&event_mutex);
3314
3315         ret = create_event_toplevel_files(parent, tr);
3316         if (ret)
3317                 goto out_unlock;
3318
3319         down_write(&trace_event_sem);
3320         __trace_early_add_event_dirs(tr);
3321         up_write(&trace_event_sem);
3322
3323  out_unlock:
3324         mutex_unlock(&event_mutex);
3325
3326         return ret;
3327 }
3328
3329 /* Must be called with event_mutex held */
3330 int event_trace_del_tracer(struct trace_array *tr)
3331 {
3332         lockdep_assert_held(&event_mutex);
3333
3334         /* Disable any event triggers and associated soft-disabled events */
3335         clear_event_triggers(tr);
3336
3337         /* Clear the pid list */
3338         __ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
3339
3340         /* Disable any running events */
3341         __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
3342
3343         /* Make sure no more events are being executed */
3344         tracepoint_synchronize_unregister();
3345
3346         down_write(&trace_event_sem);
3347         __trace_remove_event_dirs(tr);
3348         tracefs_remove(tr->event_dir);
3349         up_write(&trace_event_sem);
3350
3351         tr->event_dir = NULL;
3352
3353         return 0;
3354 }
3355
3356 static __init int event_trace_memsetup(void)
3357 {
3358         field_cachep = KMEM_CACHE(ftrace_event_field, SLAB_PANIC);
3359         file_cachep = KMEM_CACHE(trace_event_file, SLAB_PANIC);
3360         return 0;
3361 }
3362
3363 static __init void
3364 early_enable_events(struct trace_array *tr, bool disable_first)
3365 {
3366         char *buf = bootup_event_buf;
3367         char *token;
3368         int ret;
3369
3370         while (true) {
3371                 token = strsep(&buf, ",");
3372
3373                 if (!token)
3374                         break;
3375
3376                 if (*token) {
3377                         /* Restarting syscalls requires that we stop them first */
3378                         if (disable_first)
3379                                 ftrace_set_clr_event(tr, token, 0);
3380
3381                         ret = ftrace_set_clr_event(tr, token, 1);
3382                         if (ret)
3383                                 pr_warn("Failed to enable trace event: %s\n", token);
3384                 }
3385
3386                 /* Put back the comma to allow this to be called again */
3387                 if (buf)
3388                         *(buf - 1) = ',';
3389         }
3390 }
3391
3392 static __init int event_trace_enable(void)
3393 {
3394         struct trace_array *tr = top_trace_array();
3395         struct trace_event_call **iter, *call;
3396         int ret;
3397
3398         if (!tr)
3399                 return -ENODEV;
3400
3401         for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
3402
3403                 call = *iter;
3404                 ret = event_init(call);
3405                 if (!ret)
3406                         list_add(&call->list, &ftrace_events);
3407         }
3408
3409         /*
3410          * We need the top trace array to have a working set of trace
3411          * points at early init, before the debug files and directories
3412          * are created. Create the file entries now, and attach them
3413          * to the actual file dentries later.
3414          */
3415         __trace_early_add_events(tr);
3416
3417         early_enable_events(tr, false);
3418
3419         trace_printk_start_comm();
3420
3421         register_event_cmds();
3422
3423         register_trigger_cmds();
3424
3425         return 0;
3426 }
3427
3428 /*
3429  * event_trace_enable() is called from trace_event_init() first to
3430  * initialize events and perhaps start any events that are on the
3431  * command line. Unfortunately, there are some events that will not
3432  * start this early, like the system call tracepoints that need
3433  * to set the %SYSCALL_WORK_SYSCALL_TRACEPOINT flag of pid 1. But
3434  * event_trace_enable() is called before pid 1 starts, and this flag
3435  * is never set, making the syscall tracepoint never get reached, but
3436  * the event is enabled regardless (and not doing anything).
3437  */
3438 static __init int event_trace_enable_again(void)
3439 {
3440         struct trace_array *tr;
3441
3442         tr = top_trace_array();
3443         if (!tr)
3444                 return -ENODEV;
3445
3446         early_enable_events(tr, true);
3447
3448         return 0;
3449 }
3450
3451 early_initcall(event_trace_enable_again);
3452
3453 /* Init fields which doesn't related to the tracefs */
3454 static __init int event_trace_init_fields(void)
3455 {
3456         if (trace_define_generic_fields())
3457                 pr_warn("tracing: Failed to allocated generic fields");
3458
3459         if (trace_define_common_fields())
3460                 pr_warn("tracing: Failed to allocate common fields");
3461
3462         return 0;
3463 }
3464
3465 __init int event_trace_init(void)
3466 {
3467         struct trace_array *tr;
3468         struct dentry *entry;
3469         int ret;
3470
3471         tr = top_trace_array();
3472         if (!tr)
3473                 return -ENODEV;
3474
3475         entry = tracefs_create_file("available_events", 0444, NULL,
3476                                     tr, &ftrace_avail_fops);
3477         if (!entry)
3478                 pr_warn("Could not create tracefs 'available_events' entry\n");
3479
3480         ret = early_event_add_tracer(NULL, tr);
3481         if (ret)
3482                 return ret;
3483
3484 #ifdef CONFIG_MODULES
3485         ret = register_module_notifier(&trace_module_nb);
3486         if (ret)
3487                 pr_warn("Failed to register trace events module notifier\n");
3488 #endif
3489
3490         eventdir_initialized = true;
3491
3492         return 0;
3493 }
3494
3495 void __init trace_event_init(void)
3496 {
3497         event_trace_memsetup();
3498         init_ftrace_syscalls();
3499         event_trace_enable();
3500         event_trace_init_fields();
3501 }
3502
3503 #ifdef CONFIG_EVENT_TRACE_STARTUP_TEST
3504
3505 static DEFINE_SPINLOCK(test_spinlock);
3506 static DEFINE_SPINLOCK(test_spinlock_irq);
3507 static DEFINE_MUTEX(test_mutex);
3508
3509 static __init void test_work(struct work_struct *dummy)
3510 {
3511         spin_lock(&test_spinlock);
3512         spin_lock_irq(&test_spinlock_irq);
3513         udelay(1);
3514         spin_unlock_irq(&test_spinlock_irq);
3515         spin_unlock(&test_spinlock);
3516
3517         mutex_lock(&test_mutex);
3518         msleep(1);
3519         mutex_unlock(&test_mutex);
3520 }
3521
3522 static __init int event_test_thread(void *unused)
3523 {
3524         void *test_malloc;
3525
3526         test_malloc = kmalloc(1234, GFP_KERNEL);
3527         if (!test_malloc)
3528                 pr_info("failed to kmalloc\n");
3529
3530         schedule_on_each_cpu(test_work);
3531
3532         kfree(test_malloc);
3533
3534         set_current_state(TASK_INTERRUPTIBLE);
3535         while (!kthread_should_stop()) {
3536                 schedule();
3537                 set_current_state(TASK_INTERRUPTIBLE);
3538         }
3539         __set_current_state(TASK_RUNNING);
3540
3541         return 0;
3542 }
3543
3544 /*
3545  * Do various things that may trigger events.
3546  */
3547 static __init void event_test_stuff(void)
3548 {
3549         struct task_struct *test_thread;
3550
3551         test_thread = kthread_run(event_test_thread, NULL, "test-events");
3552         msleep(1);
3553         kthread_stop(test_thread);
3554 }
3555
3556 /*
3557  * For every trace event defined, we will test each trace point separately,
3558  * and then by groups, and finally all trace points.
3559  */
3560 static __init void event_trace_self_tests(void)
3561 {
3562         struct trace_subsystem_dir *dir;
3563         struct trace_event_file *file;
3564         struct trace_event_call *call;
3565         struct event_subsystem *system;
3566         struct trace_array *tr;
3567         int ret;
3568
3569         tr = top_trace_array();
3570         if (!tr)
3571                 return;
3572
3573         pr_info("Running tests on trace events:\n");
3574
3575         list_for_each_entry(file, &tr->events, list) {
3576
3577                 call = file->event_call;
3578
3579                 /* Only test those that have a probe */
3580                 if (!call->class || !call->class->probe)
3581                         continue;
3582
3583 /*
3584  * Testing syscall events here is pretty useless, but
3585  * we still do it if configured. But this is time consuming.
3586  * What we really need is a user thread to perform the
3587  * syscalls as we test.
3588  */
3589 #ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
3590                 if (call->class->system &&
3591                     strcmp(call->class->system, "syscalls") == 0)
3592                         continue;
3593 #endif
3594
3595                 pr_info("Testing event %s: ", trace_event_name(call));
3596
3597                 /*
3598                  * If an event is already enabled, someone is using
3599                  * it and the self test should not be on.
3600                  */
3601                 if (file->flags & EVENT_FILE_FL_ENABLED) {
3602                         pr_warn("Enabled event during self test!\n");
3603                         WARN_ON_ONCE(1);
3604                         continue;
3605                 }
3606
3607                 ftrace_event_enable_disable(file, 1);
3608                 event_test_stuff();
3609                 ftrace_event_enable_disable(file, 0);
3610
3611                 pr_cont("OK\n");
3612         }
3613
3614         /* Now test at the sub system level */
3615
3616         pr_info("Running tests on trace event systems:\n");
3617
3618         list_for_each_entry(dir, &tr->systems, list) {
3619
3620                 system = dir->subsystem;
3621
3622                 /* the ftrace system is special, skip it */
3623                 if (strcmp(system->name, "ftrace") == 0)
3624                         continue;
3625
3626                 pr_info("Testing event system %s: ", system->name);
3627
3628                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1);
3629                 if (WARN_ON_ONCE(ret)) {
3630                         pr_warn("error enabling system %s\n",
3631                                 system->name);
3632                         continue;
3633                 }
3634
3635                 event_test_stuff();
3636
3637                 ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0);
3638                 if (WARN_ON_ONCE(ret)) {
3639                         pr_warn("error disabling system %s\n",
3640                                 system->name);
3641                         continue;
3642                 }
3643
3644                 pr_cont("OK\n");
3645         }
3646
3647         /* Test with all events enabled */
3648
3649         pr_info("Running tests on all trace events:\n");
3650         pr_info("Testing all events: ");
3651
3652         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1);
3653         if (WARN_ON_ONCE(ret)) {
3654                 pr_warn("error enabling all events\n");
3655                 return;
3656         }
3657
3658         event_test_stuff();
3659
3660         /* reset sysname */
3661         ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0);
3662         if (WARN_ON_ONCE(ret)) {
3663                 pr_warn("error disabling all events\n");
3664                 return;
3665         }
3666
3667         pr_cont("OK\n");
3668 }
3669
3670 #ifdef CONFIG_FUNCTION_TRACER
3671
3672 static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
3673
3674 static struct trace_event_file event_trace_file __initdata;
3675
3676 static void __init
3677 function_test_events_call(unsigned long ip, unsigned long parent_ip,
3678                           struct ftrace_ops *op, struct ftrace_regs *regs)
3679 {
3680         struct trace_buffer *buffer;
3681         struct ring_buffer_event *event;
3682         struct ftrace_entry *entry;
3683         unsigned int trace_ctx;
3684         long disabled;
3685         int cpu;
3686
3687         trace_ctx = tracing_gen_ctx();
3688         preempt_disable_notrace();
3689         cpu = raw_smp_processor_id();
3690         disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
3691
3692         if (disabled != 1)
3693                 goto out;
3694
3695         event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
3696                                                 TRACE_FN, sizeof(*entry),
3697                                                 trace_ctx);
3698         if (!event)
3699                 goto out;
3700         entry   = ring_buffer_event_data(event);
3701         entry->ip                       = ip;
3702         entry->parent_ip                = parent_ip;
3703
3704         event_trigger_unlock_commit(&event_trace_file, buffer, event,
3705                                     entry, trace_ctx);
3706  out:
3707         atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
3708         preempt_enable_notrace();
3709 }
3710
3711 static struct ftrace_ops trace_ops __initdata  =
3712 {
3713         .func = function_test_events_call,
3714 };
3715
3716 static __init void event_trace_self_test_with_function(void)
3717 {
3718         int ret;
3719
3720         event_trace_file.tr = top_trace_array();
3721         if (WARN_ON(!event_trace_file.tr))
3722                 return;
3723
3724         ret = register_ftrace_function(&trace_ops);
3725         if (WARN_ON(ret < 0)) {
3726                 pr_info("Failed to enable function tracer for event tests\n");
3727                 return;
3728         }
3729         pr_info("Running tests again, along with the function tracer\n");
3730         event_trace_self_tests();
3731         unregister_ftrace_function(&trace_ops);
3732 }
3733 #else
3734 static __init void event_trace_self_test_with_function(void)
3735 {
3736 }
3737 #endif
3738
3739 static __init int event_trace_self_tests_init(void)
3740 {
3741         if (!tracing_selftest_disabled) {
3742                 event_trace_self_tests();
3743                 event_trace_self_test_with_function();
3744         }
3745
3746         return 0;
3747 }
3748
3749 late_initcall(event_trace_self_tests_init);
3750
3751 #endif