kernel/trace/trace_events_trigger.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_trigger - trace event triggers
   4  *
   5  * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/ctype.h>
  10 #include <linux/mutex.h>
  11 #include <linux/slab.h>
  12 #include <linux/rculist.h>
  13
  14 #include "trace.h"
  15
  16 static LIST_HEAD(trigger_commands);
  17 static DEFINE_MUTEX(trigger_cmd_mutex);
  18
  19 void trigger_data_free(struct event_trigger_data *data)
  20 {
  21         if (data->cmd_ops->set_filter)
  22                 data->cmd_ops->set_filter(NULL, data, NULL);
  23
  24         /* make sure current triggers exit before free */
  25         tracepoint_synchronize_unregister();
  26
  27         kfree(data);
  28 }
  29
  30 /**
  31  * event_triggers_call - Call triggers associated with a trace event
  32  * @file: The trace_event_file associated with the event
  33  * @rec: The trace entry for the event, NULL for unconditional invocation
  34  *
  35  * For each trigger associated with an event, invoke the trigger
  36  * function registered with the associated trigger command.  If rec is
  37  * non-NULL, it means that the trigger requires further processing and
  38  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
  39  * trigger has a filter associated with it, rec will checked against
  40  * the filter and if the record matches the trigger will be invoked.
  41  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
  42  * in any case until the current event is written, the trigger
  43  * function isn't invoked but the bit associated with the deferred
  44  * trigger is set in the return value.
  45  *
  46  * Returns an enum event_trigger_type value containing a set bit for
  47  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  48  *
  49  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  50  *
  51  * Return: an enum event_trigger_type value containing a set bit for
  52  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  53  */
  54 enum event_trigger_type
  55 event_triggers_call(struct trace_event_file *file, void *rec,
  56                     struct ring_buffer_event *event)
  57 {
  58         struct event_trigger_data *data;
  59         enum event_trigger_type tt = ETT_NONE;
  60         struct event_filter *filter;
  61
  62         if (list_empty(&file->triggers))
  63                 return tt;
  64
  65         list_for_each_entry_rcu(data, &file->triggers, list) {
  66                 if (data->paused)
  67                         continue;
  68                 if (!rec) {
  69                         data->ops->func(data, rec, event);
  70                         continue;
  71                 }
  72                 filter = rcu_dereference_sched(data->filter);
  73                 if (filter && !filter_match_preds(filter, rec))
  74                         continue;
  75                 if (event_command_post_trigger(data->cmd_ops)) {
  76                         tt |= data->cmd_ops->trigger_type;
  77                         continue;
  78                 }
  79                 data->ops->func(data, rec, event);
  80         }
  81         return tt;
  82 }
  83 EXPORT_SYMBOL_GPL(event_triggers_call);
  84
  85 /**
  86  * event_triggers_post_call - Call 'post_triggers' for a trace event
  87  * @file: The trace_event_file associated with the event
  88  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
  89  *
  90  * For each trigger associated with an event, invoke the trigger
  91  * function registered with the associated trigger command, if the
  92  * corresponding bit is set in the tt enum passed into this function.
  93  * See @event_triggers_call for details on how those bits are set.
  94  *
  95  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  96  */
  97 void
  98 event_triggers_post_call(struct trace_event_file *file,
  99                          enum event_trigger_type tt)
 100 {
 101         struct event_trigger_data *data;
 102
 103         list_for_each_entry_rcu(data, &file->triggers, list) {
 104                 if (data->paused)
 105                         continue;
 106                 if (data->cmd_ops->trigger_type & tt)
 107                         data->ops->func(data, NULL, NULL);
 108         }
 109 }
 110 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 111
 112 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 113
 114 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 115 {
 116         struct trace_event_file *event_file = event_file_data(m->private);
 117
 118         if (t == SHOW_AVAILABLE_TRIGGERS) {
 119                 (*pos)++;
 120                 return NULL;
 121         }
 122         return seq_list_next(t, &event_file->triggers, pos);
 123 }
 124
 125 static void *trigger_start(struct seq_file *m, loff_t *pos)
 126 {
 127         struct trace_event_file *event_file;
 128
 129         /* ->stop() is called even if ->start() fails */
 130         mutex_lock(&event_mutex);
 131         event_file = event_file_data(m->private);
 132         if (unlikely(!event_file))
 133                 return ERR_PTR(-ENODEV);
 134
 135         if (list_empty(&event_file->triggers))
 136                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 137
 138         return seq_list_start(&event_file->triggers, *pos);
 139 }
 140
 141 static void trigger_stop(struct seq_file *m, void *t)
 142 {
 143         mutex_unlock(&event_mutex);
 144 }
 145
 146 static int trigger_show(struct seq_file *m, void *v)
 147 {
 148         struct event_trigger_data *data;
 149         struct event_command *p;
 150
 151         if (v == SHOW_AVAILABLE_TRIGGERS) {
 152                 seq_puts(m, "# Available triggers:\n");
 153                 seq_putc(m, '#');
 154                 mutex_lock(&trigger_cmd_mutex);
 155                 list_for_each_entry_reverse(p, &trigger_commands, list)
 156                         seq_printf(m, " %s", p->name);
 157                 seq_putc(m, '\n');
 158                 mutex_unlock(&trigger_cmd_mutex);
 159                 return 0;
 160         }
 161
 162         data = list_entry(v, struct event_trigger_data, list);
 163         data->ops->print(m, data->ops, data);
 164
 165         return 0;
 166 }
 167
 168 static const struct seq_operations event_triggers_seq_ops = {
 169         .start = trigger_start,
 170         .next = trigger_next,
 171         .stop = trigger_stop,
 172         .show = trigger_show,
 173 };
 174
 175 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 176 {
 177         int ret = 0;
 178
 179         mutex_lock(&event_mutex);
 180
 181         if (unlikely(!event_file_data(file))) {
 182                 mutex_unlock(&event_mutex);
 183                 return -ENODEV;
 184         }
 185
 186         if ((file->f_mode & FMODE_WRITE) &&
 187             (file->f_flags & O_TRUNC)) {
 188                 struct trace_event_file *event_file;
 189                 struct event_command *p;
 190
 191                 event_file = event_file_data(file);
 192
 193                 list_for_each_entry(p, &trigger_commands, list) {
 194                         if (p->unreg_all)
 195                                 p->unreg_all(event_file);
 196                 }
 197         }
 198
 199         if (file->f_mode & FMODE_READ) {
 200                 ret = seq_open(file, &event_triggers_seq_ops);
 201                 if (!ret) {
 202                         struct seq_file *m = file->private_data;
 203                         m->private = file;
 204                 }
 205         }
 206
 207         mutex_unlock(&event_mutex);
 208
 209         return ret;
 210 }
 211
 212 static int trigger_process_regex(struct trace_event_file *file, char *buff)
 213 {
 214         char *command, *next;
 215         struct event_command *p;
 216         int ret = -EINVAL;
 217
 218         next = buff = skip_spaces(buff);
 219         command = strsep(&next, ": \t");
 220         if (next) {
 221                 next = skip_spaces(next);
 222                 if (!*next)
 223                         next = NULL;
 224         }
 225         command = (command[0] != '!') ? command : command + 1;
 226
 227         mutex_lock(&trigger_cmd_mutex);
 228         list_for_each_entry(p, &trigger_commands, list) {
 229                 if (strcmp(p->name, command) == 0) {
 230                         ret = p->func(p, file, buff, command, next);
 231                         goto out_unlock;
 232                 }
 233         }
 234  out_unlock:
 235         mutex_unlock(&trigger_cmd_mutex);
 236
 237         return ret;
 238 }
 239
 240 static ssize_t event_trigger_regex_write(struct file *file,
 241                                          const char __user *ubuf,
 242                                          size_t cnt, loff_t *ppos)
 243 {
 244         struct trace_event_file *event_file;
 245         ssize_t ret;
 246         char *buf;
 247
 248         if (!cnt)
 249                 return 0;
 250
 251         if (cnt >= PAGE_SIZE)
 252                 return -EINVAL;
 253
 254         buf = memdup_user_nul(ubuf, cnt);
 255         if (IS_ERR(buf))
 256                 return PTR_ERR(buf);
 257
 258         strim(buf);
 259
 260         mutex_lock(&event_mutex);
 261         event_file = event_file_data(file);
 262         if (unlikely(!event_file)) {
 263                 mutex_unlock(&event_mutex);
 264                 kfree(buf);
 265                 return -ENODEV;
 266         }
 267         ret = trigger_process_regex(event_file, buf);
 268         mutex_unlock(&event_mutex);
 269
 270         kfree(buf);
 271         if (ret < 0)
 272                 goto out;
 273
 274         *ppos += cnt;
 275         ret = cnt;
 276  out:
 277         return ret;
 278 }
 279
 280 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 281 {
 282         mutex_lock(&event_mutex);
 283
 284         if (file->f_mode & FMODE_READ)
 285                 seq_release(inode, file);
 286
 287         mutex_unlock(&event_mutex);
 288
 289         return 0;
 290 }
 291
 292 static ssize_t
 293 event_trigger_write(struct file *filp, const char __user *ubuf,
 294                     size_t cnt, loff_t *ppos)
 295 {
 296         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 297 }
 298
 299 static int
 300 event_trigger_open(struct inode *inode, struct file *filp)
 301 {
 302         return event_trigger_regex_open(inode, filp);
 303 }
 304
 305 static int
 306 event_trigger_release(struct inode *inode, struct file *file)
 307 {
 308         return event_trigger_regex_release(inode, file);
 309 }
 310
 311 const struct file_operations event_trigger_fops = {
 312         .open = event_trigger_open,
 313         .read = seq_read,
 314         .write = event_trigger_write,
 315         .llseek = tracing_lseek,
 316         .release = event_trigger_release,
 317 };
 318
 319 /*
 320  * Currently we only register event commands from __init, so mark this
 321  * __init too.
 322  */
 323 __init int register_event_command(struct event_command *cmd)
 324 {
 325         struct event_command *p;
 326         int ret = 0;
 327
 328         mutex_lock(&trigger_cmd_mutex);
 329         list_for_each_entry(p, &trigger_commands, list) {
 330                 if (strcmp(cmd->name, p->name) == 0) {
 331                         ret = -EBUSY;
 332                         goto out_unlock;
 333                 }
 334         }
 335         list_add(&cmd->list, &trigger_commands);
 336  out_unlock:
 337         mutex_unlock(&trigger_cmd_mutex);
 338
 339         return ret;
 340 }
 341
 342 /*
 343  * Currently we only unregister event commands from __init, so mark
 344  * this __init too.
 345  */
 346 __init int unregister_event_command(struct event_command *cmd)
 347 {
 348         struct event_command *p, *n;
 349         int ret = -ENODEV;
 350
 351         mutex_lock(&trigger_cmd_mutex);
 352         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 353                 if (strcmp(cmd->name, p->name) == 0) {
 354                         ret = 0;
 355                         list_del_init(&p->list);
 356                         goto out_unlock;
 357                 }
 358         }
 359  out_unlock:
 360         mutex_unlock(&trigger_cmd_mutex);
 361
 362         return ret;
 363 }
 364
 365 /**
 366  * event_trigger_print - Generic event_trigger_ops @print implementation
 367  * @name: The name of the event trigger
 368  * @m: The seq_file being printed to
 369  * @data: Trigger-specific data
 370  * @filter_str: filter_str to print, if present
 371  *
 372  * Common implementation for event triggers to print themselves.
 373  *
 374  * Usually wrapped by a function that simply sets the @name of the
 375  * trigger command and then invokes this.
 376  *
 377  * Return: 0 on success, errno otherwise
 378  */
 379 static int
 380 event_trigger_print(const char *name, struct seq_file *m,
 381                     void *data, char *filter_str)
 382 {
 383         long count = (long)data;
 384
 385         seq_puts(m, name);
 386
 387         if (count == -1)
 388                 seq_puts(m, ":unlimited");
 389         else
 390                 seq_printf(m, ":count=%ld", count);
 391
 392         if (filter_str)
 393                 seq_printf(m, " if %s\n", filter_str);
 394         else
 395                 seq_putc(m, '\n');
 396
 397         return 0;
 398 }
 399
 400 /**
 401  * event_trigger_init - Generic event_trigger_ops @init implementation
 402  * @ops: The trigger ops associated with the trigger
 403  * @data: Trigger-specific data
 404  *
 405  * Common implementation of event trigger initialization.
 406  *
 407  * Usually used directly as the @init method in event trigger
 408  * implementations.
 409  *
 410  * Return: 0 on success, errno otherwise
 411  */
 412 int event_trigger_init(struct event_trigger_ops *ops,
 413                        struct event_trigger_data *data)
 414 {
 415         data->ref++;
 416         return 0;
 417 }
 418
 419 /**
 420  * event_trigger_free - Generic event_trigger_ops @free implementation
 421  * @ops: The trigger ops associated with the trigger
 422  * @data: Trigger-specific data
 423  *
 424  * Common implementation of event trigger de-initialization.
 425  *
 426  * Usually used directly as the @free method in event trigger
 427  * implementations.
 428  */
 429 static void
 430 event_trigger_free(struct event_trigger_ops *ops,
 431                    struct event_trigger_data *data)
 432 {
 433         if (WARN_ON_ONCE(data->ref <= 0))
 434                 return;
 435
 436         data->ref--;
 437         if (!data->ref)
 438                 trigger_data_free(data);
 439 }
 440
 441 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 442                                        int trigger_enable)
 443 {
 444         int ret = 0;
 445
 446         if (trigger_enable) {
 447                 if (atomic_inc_return(&file->tm_ref) > 1)
 448                         return ret;
 449                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 450                 ret = trace_event_enable_disable(file, 1, 1);
 451         } else {
 452                 if (atomic_dec_return(&file->tm_ref) > 0)
 453                         return ret;
 454                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 455                 ret = trace_event_enable_disable(file, 0, 1);
 456         }
 457
 458         return ret;
 459 }
 460
 461 /**
 462  * clear_event_triggers - Clear all triggers associated with a trace array
 463  * @tr: The trace array to clear
 464  *
 465  * For each trigger, the triggering event has its tm_ref decremented
 466  * via trace_event_trigger_enable_disable(), and any associated event
 467  * (in the case of enable/disable_event triggers) will have its sm_ref
 468  * decremented via free()->trace_event_enable_disable().  That
 469  * combination effectively reverses the soft-mode/trigger state added
 470  * by trigger registration.
 471  *
 472  * Must be called with event_mutex held.
 473  */
 474 void
 475 clear_event_triggers(struct trace_array *tr)
 476 {
 477         struct trace_event_file *file;
 478
 479         list_for_each_entry(file, &tr->events, list) {
 480                 struct event_trigger_data *data, *n;
 481                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 482                         trace_event_trigger_enable_disable(file, 0);
 483                         list_del_rcu(&data->list);
 484                         if (data->ops->free)
 485                                 data->ops->free(data->ops, data);
 486                 }
 487         }
 488 }
 489
 490 /**
 491  * update_cond_flag - Set or reset the TRIGGER_COND bit
 492  * @file: The trace_event_file associated with the event
 493  *
 494  * If an event has triggers and any of those triggers has a filter or
 495  * a post_trigger, trigger invocation needs to be deferred until after
 496  * the current event has logged its data, and the event should have
 497  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 498  * cleared.
 499  */
 500 void update_cond_flag(struct trace_event_file *file)
 501 {
 502         struct event_trigger_data *data;
 503         bool set_cond = false;
 504
 505         lockdep_assert_held(&event_mutex);
 506
 507         list_for_each_entry(data, &file->triggers, list) {
 508                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 509                     event_command_needs_rec(data->cmd_ops)) {
 510                         set_cond = true;
 511                         break;
 512                 }
 513         }
 514
 515         if (set_cond)
 516                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 517         else
 518                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 519 }
 520
 521 /**
 522  * register_trigger - Generic event_command @reg implementation
 523  * @glob: The raw string used to register the trigger
 524  * @ops: The trigger ops associated with the trigger
 525  * @data: Trigger-specific data to associate with the trigger
 526  * @file: The trace_event_file associated with the event
 527  *
 528  * Common implementation for event trigger registration.
 529  *
 530  * Usually used directly as the @reg method in event command
 531  * implementations.
 532  *
 533  * Return: 0 on success, errno otherwise
 534  */
 535 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 536                             struct event_trigger_data *data,
 537                             struct trace_event_file *file)
 538 {
 539         struct event_trigger_data *test;
 540         int ret = 0;
 541
 542         lockdep_assert_held(&event_mutex);
 543
 544         list_for_each_entry(test, &file->triggers, list) {
 545                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 546                         ret = -EEXIST;
 547                         goto out;
 548                 }
 549         }
 550
 551         if (data->ops->init) {
 552                 ret = data->ops->init(data->ops, data);
 553                 if (ret < 0)
 554                         goto out;
 555         }
 556
 557         list_add_rcu(&data->list, &file->triggers);
 558         ret++;
 559
 560         update_cond_flag(file);
 561         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 562                 list_del_rcu(&data->list);
 563                 update_cond_flag(file);
 564                 ret--;
 565         }
 566 out:
 567         return ret;
 568 }
 569
 570 /**
 571  * unregister_trigger - Generic event_command @unreg implementation
 572  * @glob: The raw string used to register the trigger
 573  * @ops: The trigger ops associated with the trigger
 574  * @test: Trigger-specific data used to find the trigger to remove
 575  * @file: The trace_event_file associated with the event
 576  *
 577  * Common implementation for event trigger unregistration.
 578  *
 579  * Usually used directly as the @unreg method in event command
 580  * implementations.
 581  */
 582 static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 583                                struct event_trigger_data *test,
 584                                struct trace_event_file *file)
 585 {
 586         struct event_trigger_data *data;
 587         bool unregistered = false;
 588
 589         lockdep_assert_held(&event_mutex);
 590
 591         list_for_each_entry(data, &file->triggers, list) {
 592                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 593                         unregistered = true;
 594                         list_del_rcu(&data->list);
 595                         trace_event_trigger_enable_disable(file, 0);
 596                         update_cond_flag(file);
 597                         break;
 598                 }
 599         }
 600
 601         if (unregistered && data->ops->free)
 602                 data->ops->free(data->ops, data);
 603 }
 604
 605 /**
 606  * event_trigger_callback - Generic event_command @func implementation
 607  * @cmd_ops: The command ops, used for trigger registration
 608  * @file: The trace_event_file associated with the event
 609  * @glob: The raw string used to register the trigger
 610  * @cmd: The cmd portion of the string used to register the trigger
 611  * @param: The params portion of the string used to register the trigger
 612  *
 613  * Common implementation for event command parsing and trigger
 614  * instantiation.
 615  *
 616  * Usually used directly as the @func method in event command
 617  * implementations.
 618  *
 619  * Return: 0 on success, errno otherwise
 620  */
 621 static int
 622 event_trigger_callback(struct event_command *cmd_ops,
 623                        struct trace_event_file *file,
 624                        char *glob, char *cmd, char *param)
 625 {
 626         struct event_trigger_data *trigger_data;
 627         struct event_trigger_ops *trigger_ops;
 628         char *trigger = NULL;
 629         char *number;
 630         int ret;
 631
 632         /* separate the trigger from the filter (t:n [if filter]) */
 633         if (param && isdigit(param[0])) {
 634                 trigger = strsep(&param, " \t");
 635                 if (param) {
 636                         param = skip_spaces(param);
 637                         if (!*param)
 638                                 param = NULL;
 639                 }
 640         }
 641
 642         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 643
 644         ret = -ENOMEM;
 645         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 646         if (!trigger_data)
 647                 goto out;
 648
 649         trigger_data->count = -1;
 650         trigger_data->ops = trigger_ops;
 651         trigger_data->cmd_ops = cmd_ops;
 652         trigger_data->private_data = file;
 653         INIT_LIST_HEAD(&trigger_data->list);
 654         INIT_LIST_HEAD(&trigger_data->named_list);
 655
 656         if (glob[0] == '!') {
 657                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 658                 kfree(trigger_data);
 659                 ret = 0;
 660                 goto out;
 661         }
 662
 663         if (trigger) {
 664                 number = strsep(&trigger, ":");
 665
 666                 ret = -EINVAL;
 667                 if (!strlen(number))
 668                         goto out_free;
 669
 670                 /*
 671                  * We use the callback data field (which is a pointer)
 672                  * as our counter.
 673                  */
 674                 ret = kstrtoul(number, 0, &trigger_data->count);
 675                 if (ret)
 676                         goto out_free;
 677         }
 678
 679         if (!param) /* if param is non-empty, it's supposed to be a filter */
 680                 goto out_reg;
 681
 682         if (!cmd_ops->set_filter)
 683                 goto out_reg;
 684
 685         ret = cmd_ops->set_filter(param, trigger_data, file);
 686         if (ret < 0)
 687                 goto out_free;
 688
 689  out_reg:
 690         /* Up the trigger_data count to make sure reg doesn't free it on failure */
 691         event_trigger_init(trigger_ops, trigger_data);
 692         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 693         /*
 694          * The above returns on success the # of functions enabled,
 695          * but if it didn't find any functions it returns zero.
 696          * Consider no functions a failure too.
 697          */
 698         if (!ret) {
 699                 cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 700                 ret = -ENOENT;
 701         } else if (ret > 0)
 702                 ret = 0;
 703
 704         /* Down the counter of trigger_data or free it if not used anymore */
 705         event_trigger_free(trigger_ops, trigger_data);
 706  out:
 707         return ret;
 708
 709  out_free:
 710         if (cmd_ops->set_filter)
 711                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 712         kfree(trigger_data);
 713         goto out;
 714 }
 715
 716 /**
 717  * set_trigger_filter - Generic event_command @set_filter implementation
 718  * @filter_str: The filter string for the trigger, NULL to remove filter
 719  * @trigger_data: Trigger-specific data
 720  * @file: The trace_event_file associated with the event
 721  *
 722  * Common implementation for event command filter parsing and filter
 723  * instantiation.
 724  *
 725  * Usually used directly as the @set_filter method in event command
 726  * implementations.
 727  *
 728  * Also used to remove a filter (if filter_str = NULL).
 729  *
 730  * Return: 0 on success, errno otherwise
 731  */
 732 int set_trigger_filter(char *filter_str,
 733                        struct event_trigger_data *trigger_data,
 734                        struct trace_event_file *file)
 735 {
 736         struct event_trigger_data *data = trigger_data;
 737         struct event_filter *filter = NULL, *tmp;
 738         int ret = -EINVAL;
 739         char *s;
 740
 741         if (!filter_str) /* clear the current filter */
 742                 goto assign;
 743
 744         s = strsep(&filter_str, " \t");
 745
 746         if (!strlen(s) || strcmp(s, "if") != 0)
 747                 goto out;
 748
 749         if (!filter_str)
 750                 goto out;
 751
 752         /* The filter is for the 'trigger' event, not the triggered event */
 753         ret = create_event_filter(file->event_call, filter_str, false, &filter);
 754         /*
 755          * If create_event_filter() fails, filter still needs to be freed.
 756          * Which the calling code will do with data->filter.
 757          */
 758  assign:
 759         tmp = rcu_access_pointer(data->filter);
 760
 761         rcu_assign_pointer(data->filter, filter);
 762
 763         if (tmp) {
 764                 /* Make sure the call is done with the filter */
 765                 tracepoint_synchronize_unregister();
 766                 free_event_filter(tmp);
 767         }
 768
 769         kfree(data->filter_str);
 770         data->filter_str = NULL;
 771
 772         if (filter_str) {
 773                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 774                 if (!data->filter_str) {
 775                         free_event_filter(rcu_access_pointer(data->filter));
 776                         data->filter = NULL;
 777                         ret = -ENOMEM;
 778                 }
 779         }
 780  out:
 781         return ret;
 782 }
 783
 784 static LIST_HEAD(named_triggers);
 785
 786 /**
 787  * find_named_trigger - Find the common named trigger associated with @name
 788  * @name: The name of the set of named triggers to find the common data for
 789  *
 790  * Named triggers are sets of triggers that share a common set of
 791  * trigger data.  The first named trigger registered with a given name
 792  * owns the common trigger data that the others subsequently
 793  * registered with the same name will reference.  This function
 794  * returns the common trigger data associated with that first
 795  * registered instance.
 796  *
 797  * Return: the common trigger data for the given named trigger on
 798  * success, NULL otherwise.
 799  */
 800 struct event_trigger_data *find_named_trigger(const char *name)
 801 {
 802         struct event_trigger_data *data;
 803
 804         if (!name)
 805                 return NULL;
 806
 807         list_for_each_entry(data, &named_triggers, named_list) {
 808                 if (data->named_data)
 809                         continue;
 810                 if (strcmp(data->name, name) == 0)
 811                         return data;
 812         }
 813
 814         return NULL;
 815 }
 816
 817 /**
 818  * is_named_trigger - determine if a given trigger is a named trigger
 819  * @test: The trigger data to test
 820  *
 821  * Return: true if 'test' is a named trigger, false otherwise.
 822  */
 823 bool is_named_trigger(struct event_trigger_data *test)
 824 {
 825         struct event_trigger_data *data;
 826
 827         list_for_each_entry(data, &named_triggers, named_list) {
 828                 if (test == data)
 829                         return true;
 830         }
 831
 832         return false;
 833 }
 834
 835 /**
 836  * save_named_trigger - save the trigger in the named trigger list
 837  * @name: The name of the named trigger set
 838  * @data: The trigger data to save
 839  *
 840  * Return: 0 if successful, negative error otherwise.
 841  */
 842 int save_named_trigger(const char *name, struct event_trigger_data *data)
 843 {
 844         data->name = kstrdup(name, GFP_KERNEL);
 845         if (!data->name)
 846                 return -ENOMEM;
 847
 848         list_add(&data->named_list, &named_triggers);
 849
 850         return 0;
 851 }
 852
 853 /**
 854  * del_named_trigger - delete a trigger from the named trigger list
 855  * @data: The trigger data to delete
 856  */
 857 void del_named_trigger(struct event_trigger_data *data)
 858 {
 859         kfree(data->name);
 860         data->name = NULL;
 861
 862         list_del(&data->named_list);
 863 }
 864
 865 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 866 {
 867         struct event_trigger_data *test;
 868
 869         list_for_each_entry(test, &named_triggers, named_list) {
 870                 if (strcmp(test->name, data->name) == 0) {
 871                         if (pause) {
 872                                 test->paused_tmp = test->paused;
 873                                 test->paused = true;
 874                         } else {
 875                                 test->paused = test->paused_tmp;
 876                         }
 877                 }
 878         }
 879 }
 880
 881 /**
 882  * pause_named_trigger - Pause all named triggers with the same name
 883  * @data: The trigger data of a named trigger to pause
 884  *
 885  * Pauses a named trigger along with all other triggers having the
 886  * same name.  Because named triggers share a common set of data,
 887  * pausing only one is meaningless, so pausing one named trigger needs
 888  * to pause all triggers with the same name.
 889  */
 890 void pause_named_trigger(struct event_trigger_data *data)
 891 {
 892         __pause_named_trigger(data, true);
 893 }
 894
 895 /**
 896  * unpause_named_trigger - Un-pause all named triggers with the same name
 897  * @data: The trigger data of a named trigger to unpause
 898  *
 899  * Un-pauses a named trigger along with all other triggers having the
 900  * same name.  Because named triggers share a common set of data,
 901  * unpausing only one is meaningless, so unpausing one named trigger
 902  * needs to unpause all triggers with the same name.
 903  */
 904 void unpause_named_trigger(struct event_trigger_data *data)
 905 {
 906         __pause_named_trigger(data, false);
 907 }
 908
 909 /**
 910  * set_named_trigger_data - Associate common named trigger data
 911  * @data: The trigger data of a named trigger to unpause
 912  *
 913  * Named triggers are sets of triggers that share a common set of
 914  * trigger data.  The first named trigger registered with a given name
 915  * owns the common trigger data that the others subsequently
 916  * registered with the same name will reference.  This function
 917  * associates the common trigger data from the first trigger with the
 918  * given trigger.
 919  */
 920 void set_named_trigger_data(struct event_trigger_data *data,
 921                             struct event_trigger_data *named_data)
 922 {
 923         data->named_data = named_data;
 924 }
 925
 926 struct event_trigger_data *
 927 get_named_trigger_data(struct event_trigger_data *data)
 928 {
 929         return data->named_data;
 930 }
 931
 932 static void
 933 traceon_trigger(struct event_trigger_data *data, void *rec,
 934                 struct ring_buffer_event *event)
 935 {
 936         if (tracing_is_on())
 937                 return;
 938
 939         tracing_on();
 940 }
 941
 942 static void
 943 traceon_count_trigger(struct event_trigger_data *data, void *rec,
 944                       struct ring_buffer_event *event)
 945 {
 946         if (tracing_is_on())
 947                 return;
 948
 949         if (!data->count)
 950                 return;
 951
 952         if (data->count != -1)
 953                 (data->count)--;
 954
 955         tracing_on();
 956 }
 957
 958 static void
 959 traceoff_trigger(struct event_trigger_data *data, void *rec,
 960                  struct ring_buffer_event *event)
 961 {
 962         if (!tracing_is_on())
 963                 return;
 964
 965         tracing_off();
 966 }
 967
 968 static void
 969 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
 970                        struct ring_buffer_event *event)
 971 {
 972         if (!tracing_is_on())
 973                 return;
 974
 975         if (!data->count)
 976                 return;
 977
 978         if (data->count != -1)
 979                 (data->count)--;
 980
 981         tracing_off();
 982 }
 983
 984 static int
 985 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 986                       struct event_trigger_data *data)
 987 {
 988         return event_trigger_print("traceon", m, (void *)data->count,
 989                                    data->filter_str);
 990 }
 991
 992 static int
 993 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 994                        struct event_trigger_data *data)
 995 {
 996         return event_trigger_print("traceoff", m, (void *)data->count,
 997                                    data->filter_str);
 998 }
 999
1000 static struct event_trigger_ops traceon_trigger_ops = {
1001         .func                   = traceon_trigger,
1002         .print                  = traceon_trigger_print,
1003         .init                   = event_trigger_init,
1004         .free                   = event_trigger_free,
1005 };
1006
1007 static struct event_trigger_ops traceon_count_trigger_ops = {
1008         .func                   = traceon_count_trigger,
1009         .print                  = traceon_trigger_print,
1010         .init                   = event_trigger_init,
1011         .free                   = event_trigger_free,
1012 };
1013
1014 static struct event_trigger_ops traceoff_trigger_ops = {
1015         .func                   = traceoff_trigger,
1016         .print                  = traceoff_trigger_print,
1017         .init                   = event_trigger_init,
1018         .free                   = event_trigger_free,
1019 };
1020
1021 static struct event_trigger_ops traceoff_count_trigger_ops = {
1022         .func                   = traceoff_count_trigger,
1023         .print                  = traceoff_trigger_print,
1024         .init                   = event_trigger_init,
1025         .free                   = event_trigger_free,
1026 };
1027
1028 static struct event_trigger_ops *
1029 onoff_get_trigger_ops(char *cmd, char *param)
1030 {
1031         struct event_trigger_ops *ops;
1032
1033         /* we register both traceon and traceoff to this callback */
1034         if (strcmp(cmd, "traceon") == 0)
1035                 ops = param ? &traceon_count_trigger_ops :
1036                         &traceon_trigger_ops;
1037         else
1038                 ops = param ? &traceoff_count_trigger_ops :
1039                         &traceoff_trigger_ops;
1040
1041         return ops;
1042 }
1043
1044 static struct event_command trigger_traceon_cmd = {
1045         .name                   = "traceon",
1046         .trigger_type           = ETT_TRACE_ONOFF,
1047         .func                   = event_trigger_callback,
1048         .reg                    = register_trigger,
1049         .unreg                  = unregister_trigger,
1050         .get_trigger_ops        = onoff_get_trigger_ops,
1051         .set_filter             = set_trigger_filter,
1052 };
1053
1054 static struct event_command trigger_traceoff_cmd = {
1055         .name                   = "traceoff",
1056         .trigger_type           = ETT_TRACE_ONOFF,
1057         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1058         .func                   = event_trigger_callback,
1059         .reg                    = register_trigger,
1060         .unreg                  = unregister_trigger,
1061         .get_trigger_ops        = onoff_get_trigger_ops,
1062         .set_filter             = set_trigger_filter,
1063 };
1064
1065 #ifdef CONFIG_TRACER_SNAPSHOT
1066 static void
1067 snapshot_trigger(struct event_trigger_data *data, void *rec,
1068                  struct ring_buffer_event *event)
1069 {
1070         struct trace_event_file *file = data->private_data;
1071
1072         if (file)
1073                 tracing_snapshot_instance(file->tr);
1074         else
1075                 tracing_snapshot();
1076 }
1077
1078 static void
1079 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1080                        struct ring_buffer_event *event)
1081 {
1082         if (!data->count)
1083                 return;
1084
1085         if (data->count != -1)
1086                 (data->count)--;
1087
1088         snapshot_trigger(data, rec, event);
1089 }
1090
1091 static int
1092 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1093                           struct event_trigger_data *data,
1094                           struct trace_event_file *file)
1095 {
1096         if (tracing_alloc_snapshot_instance(file->tr) != 0)
1097                 return 0;
1098
1099         return register_trigger(glob, ops, data, file);
1100 }
1101
1102 static int
1103 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1104                        struct event_trigger_data *data)
1105 {
1106         return event_trigger_print("snapshot", m, (void *)data->count,
1107                                    data->filter_str);
1108 }
1109
1110 static struct event_trigger_ops snapshot_trigger_ops = {
1111         .func                   = snapshot_trigger,
1112         .print                  = snapshot_trigger_print,
1113         .init                   = event_trigger_init,
1114         .free                   = event_trigger_free,
1115 };
1116
1117 static struct event_trigger_ops snapshot_count_trigger_ops = {
1118         .func                   = snapshot_count_trigger,
1119         .print                  = snapshot_trigger_print,
1120         .init                   = event_trigger_init,
1121         .free                   = event_trigger_free,
1122 };
1123
1124 static struct event_trigger_ops *
1125 snapshot_get_trigger_ops(char *cmd, char *param)
1126 {
1127         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1128 }
1129
1130 static struct event_command trigger_snapshot_cmd = {
1131         .name                   = "snapshot",
1132         .trigger_type           = ETT_SNAPSHOT,
1133         .func                   = event_trigger_callback,
1134         .reg                    = register_snapshot_trigger,
1135         .unreg                  = unregister_trigger,
1136         .get_trigger_ops        = snapshot_get_trigger_ops,
1137         .set_filter             = set_trigger_filter,
1138 };
1139
1140 static __init int register_trigger_snapshot_cmd(void)
1141 {
1142         int ret;
1143
1144         ret = register_event_command(&trigger_snapshot_cmd);
1145         WARN_ON(ret < 0);
1146
1147         return ret;
1148 }
1149 #else
1150 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1151 #endif /* CONFIG_TRACER_SNAPSHOT */
1152
1153 #ifdef CONFIG_STACKTRACE
1154 #ifdef CONFIG_UNWINDER_ORC
1155 /* Skip 2:
1156  *   event_triggers_post_call()
1157  *   trace_event_raw_event_xxx()
1158  */
1159 # define STACK_SKIP 2
1160 #else
1161 /*
1162  * Skip 4:
1163  *   stacktrace_trigger()
1164  *   event_triggers_post_call()
1165  *   trace_event_buffer_commit()
1166  *   trace_event_raw_event_xxx()
1167  */
1168 #define STACK_SKIP 4
1169 #endif
1170
1171 static void
1172 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1173                    struct ring_buffer_event *event)
1174 {
1175         trace_dump_stack(STACK_SKIP);
1176 }
1177
1178 static void
1179 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1180                          struct ring_buffer_event *event)
1181 {
1182         if (!data->count)
1183                 return;
1184
1185         if (data->count != -1)
1186                 (data->count)--;
1187
1188         stacktrace_trigger(data, rec, event);
1189 }
1190
1191 static int
1192 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1193                          struct event_trigger_data *data)
1194 {
1195         return event_trigger_print("stacktrace", m, (void *)data->count,
1196                                    data->filter_str);
1197 }
1198
1199 static struct event_trigger_ops stacktrace_trigger_ops = {
1200         .func                   = stacktrace_trigger,
1201         .print                  = stacktrace_trigger_print,
1202         .init                   = event_trigger_init,
1203         .free                   = event_trigger_free,
1204 };
1205
1206 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1207         .func                   = stacktrace_count_trigger,
1208         .print                  = stacktrace_trigger_print,
1209         .init                   = event_trigger_init,
1210         .free                   = event_trigger_free,
1211 };
1212
1213 static struct event_trigger_ops *
1214 stacktrace_get_trigger_ops(char *cmd, char *param)
1215 {
1216         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1217 }
1218
1219 static struct event_command trigger_stacktrace_cmd = {
1220         .name                   = "stacktrace",
1221         .trigger_type           = ETT_STACKTRACE,
1222         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1223         .func                   = event_trigger_callback,
1224         .reg                    = register_trigger,
1225         .unreg                  = unregister_trigger,
1226         .get_trigger_ops        = stacktrace_get_trigger_ops,
1227         .set_filter             = set_trigger_filter,
1228 };
1229
1230 static __init int register_trigger_stacktrace_cmd(void)
1231 {
1232         int ret;
1233
1234         ret = register_event_command(&trigger_stacktrace_cmd);
1235         WARN_ON(ret < 0);
1236
1237         return ret;
1238 }
1239 #else
1240 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1241 #endif /* CONFIG_STACKTRACE */
1242
1243 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1244 {
1245         unregister_event_command(&trigger_traceon_cmd);
1246         unregister_event_command(&trigger_traceoff_cmd);
1247 }
1248
1249 static void
1250 event_enable_trigger(struct event_trigger_data *data, void *rec,
1251                      struct ring_buffer_event *event)
1252 {
1253         struct enable_trigger_data *enable_data = data->private_data;
1254
1255         if (enable_data->enable)
1256                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1257         else
1258                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1259 }
1260
1261 static void
1262 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1263                            struct ring_buffer_event *event)
1264 {
1265         struct enable_trigger_data *enable_data = data->private_data;
1266
1267         if (!data->count)
1268                 return;
1269
1270         /* Skip if the event is in a state we want to switch to */
1271         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1272                 return;
1273
1274         if (data->count != -1)
1275                 (data->count)--;
1276
1277         event_enable_trigger(data, rec, event);
1278 }
1279
1280 int event_enable_trigger_print(struct seq_file *m,
1281                                struct event_trigger_ops *ops,
1282                                struct event_trigger_data *data)
1283 {
1284         struct enable_trigger_data *enable_data = data->private_data;
1285
1286         seq_printf(m, "%s:%s:%s",
1287                    enable_data->hist ?
1288                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1289                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1290                    enable_data->file->event_call->class->system,
1291                    trace_event_name(enable_data->file->event_call));
1292
1293         if (data->count == -1)
1294                 seq_puts(m, ":unlimited");
1295         else
1296                 seq_printf(m, ":count=%ld", data->count);
1297
1298         if (data->filter_str)
1299                 seq_printf(m, " if %s\n", data->filter_str);
1300         else
1301                 seq_putc(m, '\n');
1302
1303         return 0;
1304 }
1305
1306 void event_enable_trigger_free(struct event_trigger_ops *ops,
1307                                struct event_trigger_data *data)
1308 {
1309         struct enable_trigger_data *enable_data = data->private_data;
1310
1311         if (WARN_ON_ONCE(data->ref <= 0))
1312                 return;
1313
1314         data->ref--;
1315         if (!data->ref) {
1316                 /* Remove the SOFT_MODE flag */
1317                 trace_event_enable_disable(enable_data->file, 0, 1);
1318                 module_put(enable_data->file->event_call->mod);
1319                 trigger_data_free(data);
1320                 kfree(enable_data);
1321         }
1322 }
1323
1324 static struct event_trigger_ops event_enable_trigger_ops = {
1325         .func                   = event_enable_trigger,
1326         .print                  = event_enable_trigger_print,
1327         .init                   = event_trigger_init,
1328         .free                   = event_enable_trigger_free,
1329 };
1330
1331 static struct event_trigger_ops event_enable_count_trigger_ops = {
1332         .func                   = event_enable_count_trigger,
1333         .print                  = event_enable_trigger_print,
1334         .init                   = event_trigger_init,
1335         .free                   = event_enable_trigger_free,
1336 };
1337
1338 static struct event_trigger_ops event_disable_trigger_ops = {
1339         .func                   = event_enable_trigger,
1340         .print                  = event_enable_trigger_print,
1341         .init                   = event_trigger_init,
1342         .free                   = event_enable_trigger_free,
1343 };
1344
1345 static struct event_trigger_ops event_disable_count_trigger_ops = {
1346         .func                   = event_enable_count_trigger,
1347         .print                  = event_enable_trigger_print,
1348         .init                   = event_trigger_init,
1349         .free                   = event_enable_trigger_free,
1350 };
1351
1352 int event_enable_trigger_func(struct event_command *cmd_ops,
1353                               struct trace_event_file *file,
1354                               char *glob, char *cmd, char *param)
1355 {
1356         struct trace_event_file *event_enable_file;
1357         struct enable_trigger_data *enable_data;
1358         struct event_trigger_data *trigger_data;
1359         struct event_trigger_ops *trigger_ops;
1360         struct trace_array *tr = file->tr;
1361         const char *system;
1362         const char *event;
1363         bool hist = false;
1364         char *trigger;
1365         char *number;
1366         bool enable;
1367         int ret;
1368
1369         if (!param)
1370                 return -EINVAL;
1371
1372         /* separate the trigger from the filter (s:e:n [if filter]) */
1373         trigger = strsep(&param, " \t");
1374         if (!trigger)
1375                 return -EINVAL;
1376         if (param) {
1377                 param = skip_spaces(param);
1378                 if (!*param)
1379                         param = NULL;
1380         }
1381
1382         system = strsep(&trigger, ":");
1383         if (!trigger)
1384                 return -EINVAL;
1385
1386         event = strsep(&trigger, ":");
1387
1388         ret = -EINVAL;
1389         event_enable_file = find_event_file(tr, system, event);
1390         if (!event_enable_file)
1391                 goto out;
1392
1393 #ifdef CONFIG_HIST_TRIGGERS
1394         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1395                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1396
1397         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1398                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1399 #else
1400         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1401 #endif
1402         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1403
1404         ret = -ENOMEM;
1405         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1406         if (!trigger_data)
1407                 goto out;
1408
1409         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1410         if (!enable_data) {
1411                 kfree(trigger_data);
1412                 goto out;
1413         }
1414
1415         trigger_data->count = -1;
1416         trigger_data->ops = trigger_ops;
1417         trigger_data->cmd_ops = cmd_ops;
1418         INIT_LIST_HEAD(&trigger_data->list);
1419         RCU_INIT_POINTER(trigger_data->filter, NULL);
1420
1421         enable_data->hist = hist;
1422         enable_data->enable = enable;
1423         enable_data->file = event_enable_file;
1424         trigger_data->private_data = enable_data;
1425
1426         if (glob[0] == '!') {
1427                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1428                 kfree(trigger_data);
1429                 kfree(enable_data);
1430                 ret = 0;
1431                 goto out;
1432         }
1433
1434         /* Up the trigger_data count to make sure nothing frees it on failure */
1435         event_trigger_init(trigger_ops, trigger_data);
1436
1437         if (trigger) {
1438                 number = strsep(&trigger, ":");
1439
1440                 ret = -EINVAL;
1441                 if (!strlen(number))
1442                         goto out_free;
1443
1444                 /*
1445                  * We use the callback data field (which is a pointer)
1446                  * as our counter.
1447                  */
1448                 ret = kstrtoul(number, 0, &trigger_data->count);
1449                 if (ret)
1450                         goto out_free;
1451         }
1452
1453         if (!param) /* if param is non-empty, it's supposed to be a filter */
1454                 goto out_reg;
1455
1456         if (!cmd_ops->set_filter)
1457                 goto out_reg;
1458
1459         ret = cmd_ops->set_filter(param, trigger_data, file);
1460         if (ret < 0)
1461                 goto out_free;
1462
1463  out_reg:
1464         /* Don't let event modules unload while probe registered */
1465         ret = try_module_get(event_enable_file->event_call->mod);
1466         if (!ret) {
1467                 ret = -EBUSY;
1468                 goto out_free;
1469         }
1470
1471         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1472         if (ret < 0)
1473                 goto out_put;
1474         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1475         /*
1476          * The above returns on success the # of functions enabled,
1477          * but if it didn't find any functions it returns zero.
1478          * Consider no functions a failure too.
1479          */
1480         if (!ret) {
1481                 ret = -ENOENT;
1482                 goto out_disable;
1483         } else if (ret < 0)
1484                 goto out_disable;
1485         /* Just return zero, not the number of enabled functions */
1486         ret = 0;
1487         event_trigger_free(trigger_ops, trigger_data);
1488  out:
1489         return ret;
1490
1491  out_disable:
1492         trace_event_enable_disable(event_enable_file, 0, 1);
1493  out_put:
1494         module_put(event_enable_file->event_call->mod);
1495  out_free:
1496         if (cmd_ops->set_filter)
1497                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1498         event_trigger_free(trigger_ops, trigger_data);
1499         kfree(enable_data);
1500         goto out;
1501 }
1502
1503 int event_enable_register_trigger(char *glob,
1504                                   struct event_trigger_ops *ops,
1505                                   struct event_trigger_data *data,
1506                                   struct trace_event_file *file)
1507 {
1508         struct enable_trigger_data *enable_data = data->private_data;
1509         struct enable_trigger_data *test_enable_data;
1510         struct event_trigger_data *test;
1511         int ret = 0;
1512
1513         lockdep_assert_held(&event_mutex);
1514
1515         list_for_each_entry(test, &file->triggers, list) {
1516                 test_enable_data = test->private_data;
1517                 if (test_enable_data &&
1518                     (test->cmd_ops->trigger_type ==
1519                      data->cmd_ops->trigger_type) &&
1520                     (test_enable_data->file == enable_data->file)) {
1521                         ret = -EEXIST;
1522                         goto out;
1523                 }
1524         }
1525
1526         if (data->ops->init) {
1527                 ret = data->ops->init(data->ops, data);
1528                 if (ret < 0)
1529                         goto out;
1530         }
1531
1532         list_add_rcu(&data->list, &file->triggers);
1533         ret++;
1534
1535         update_cond_flag(file);
1536         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1537                 list_del_rcu(&data->list);
1538                 update_cond_flag(file);
1539                 ret--;
1540         }
1541 out:
1542         return ret;
1543 }
1544
1545 void event_enable_unregister_trigger(char *glob,
1546                                      struct event_trigger_ops *ops,
1547                                      struct event_trigger_data *test,
1548                                      struct trace_event_file *file)
1549 {
1550         struct enable_trigger_data *test_enable_data = test->private_data;
1551         struct enable_trigger_data *enable_data;
1552         struct event_trigger_data *data;
1553         bool unregistered = false;
1554
1555         lockdep_assert_held(&event_mutex);
1556
1557         list_for_each_entry(data, &file->triggers, list) {
1558                 enable_data = data->private_data;
1559                 if (enable_data &&
1560                     (data->cmd_ops->trigger_type ==
1561                      test->cmd_ops->trigger_type) &&
1562                     (enable_data->file == test_enable_data->file)) {
1563                         unregistered = true;
1564                         list_del_rcu(&data->list);
1565                         trace_event_trigger_enable_disable(file, 0);
1566                         update_cond_flag(file);
1567                         break;
1568                 }
1569         }
1570
1571         if (unregistered && data->ops->free)
1572                 data->ops->free(data->ops, data);
1573 }
1574
1575 static struct event_trigger_ops *
1576 event_enable_get_trigger_ops(char *cmd, char *param)
1577 {
1578         struct event_trigger_ops *ops;
1579         bool enable;
1580
1581 #ifdef CONFIG_HIST_TRIGGERS
1582         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1583                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1584 #else
1585         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1586 #endif
1587         if (enable)
1588                 ops = param ? &event_enable_count_trigger_ops :
1589                         &event_enable_trigger_ops;
1590         else
1591                 ops = param ? &event_disable_count_trigger_ops :
1592                         &event_disable_trigger_ops;
1593
1594         return ops;
1595 }
1596
1597 static struct event_command trigger_enable_cmd = {
1598         .name                   = ENABLE_EVENT_STR,
1599         .trigger_type           = ETT_EVENT_ENABLE,
1600         .func                   = event_enable_trigger_func,
1601         .reg                    = event_enable_register_trigger,
1602         .unreg                  = event_enable_unregister_trigger,
1603         .get_trigger_ops        = event_enable_get_trigger_ops,
1604         .set_filter             = set_trigger_filter,
1605 };
1606
1607 static struct event_command trigger_disable_cmd = {
1608         .name                   = DISABLE_EVENT_STR,
1609         .trigger_type           = ETT_EVENT_ENABLE,
1610         .func                   = event_enable_trigger_func,
1611         .reg                    = event_enable_register_trigger,
1612         .unreg                  = event_enable_unregister_trigger,
1613         .get_trigger_ops        = event_enable_get_trigger_ops,
1614         .set_filter             = set_trigger_filter,
1615 };
1616
1617 static __init void unregister_trigger_enable_disable_cmds(void)
1618 {
1619         unregister_event_command(&trigger_enable_cmd);
1620         unregister_event_command(&trigger_disable_cmd);
1621 }
1622
1623 static __init int register_trigger_enable_disable_cmds(void)
1624 {
1625         int ret;
1626
1627         ret = register_event_command(&trigger_enable_cmd);
1628         if (WARN_ON(ret < 0))
1629                 return ret;
1630         ret = register_event_command(&trigger_disable_cmd);
1631         if (WARN_ON(ret < 0))
1632                 unregister_trigger_enable_disable_cmds();
1633
1634         return ret;
1635 }
1636
1637 static __init int register_trigger_traceon_traceoff_cmds(void)
1638 {
1639         int ret;
1640
1641         ret = register_event_command(&trigger_traceon_cmd);
1642         if (WARN_ON(ret < 0))
1643                 return ret;
1644         ret = register_event_command(&trigger_traceoff_cmd);
1645         if (WARN_ON(ret < 0))
1646                 unregister_trigger_traceon_traceoff_cmds();
1647
1648         return ret;
1649 }
1650
1651 __init int register_trigger_cmds(void)
1652 {
1653         register_trigger_traceon_traceoff_cmds();
1654         register_trigger_snapshot_cmd();
1655         register_trigger_stacktrace_cmd();
1656         register_trigger_enable_disable_cmds();
1657         register_trigger_hist_enable_disable_cmds();
1658         register_trigger_hist_cmd();
1659
1660         return 0;
1661 }