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         struct trace_event_file *file = data->private_data;
 937
 938         if (file) {
 939                 if (tracer_tracing_is_on(file->tr))
 940                         return;
 941
 942                 tracer_tracing_on(file->tr);
 943                 return;
 944         }
 945
 946         if (tracing_is_on())
 947                 return;
 948
 949         tracing_on();
 950 }
 951
 952 static void
 953 traceon_count_trigger(struct event_trigger_data *data, void *rec,
 954                       struct ring_buffer_event *event)
 955 {
 956         struct trace_event_file *file = data->private_data;
 957
 958         if (file) {
 959                 if (tracer_tracing_is_on(file->tr))
 960                         return;
 961         } else {
 962                 if (tracing_is_on())
 963                         return;
 964         }
 965
 966         if (!data->count)
 967                 return;
 968
 969         if (data->count != -1)
 970                 (data->count)--;
 971
 972         if (file)
 973                 tracer_tracing_on(file->tr);
 974         else
 975                 tracing_on();
 976 }
 977
 978 static void
 979 traceoff_trigger(struct event_trigger_data *data, void *rec,
 980                  struct ring_buffer_event *event)
 981 {
 982         struct trace_event_file *file = data->private_data;
 983
 984         if (file) {
 985                 if (!tracer_tracing_is_on(file->tr))
 986                         return;
 987
 988                 tracer_tracing_off(file->tr);
 989                 return;
 990         }
 991
 992         if (!tracing_is_on())
 993                 return;
 994
 995         tracing_off();
 996 }
 997
 998 static void
 999 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
1000                        struct ring_buffer_event *event)
1001 {
1002         struct trace_event_file *file = data->private_data;
1003
1004         if (file) {
1005                 if (!tracer_tracing_is_on(file->tr))
1006                         return;
1007         } else {
1008                 if (!tracing_is_on())
1009                         return;
1010         }
1011
1012         if (!data->count)
1013                 return;
1014
1015         if (data->count != -1)
1016                 (data->count)--;
1017
1018         if (file)
1019                 tracer_tracing_off(file->tr);
1020         else
1021                 tracing_off();
1022 }
1023
1024 static int
1025 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1026                       struct event_trigger_data *data)
1027 {
1028         return event_trigger_print("traceon", m, (void *)data->count,
1029                                    data->filter_str);
1030 }
1031
1032 static int
1033 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1034                        struct event_trigger_data *data)
1035 {
1036         return event_trigger_print("traceoff", m, (void *)data->count,
1037                                    data->filter_str);
1038 }
1039
1040 static struct event_trigger_ops traceon_trigger_ops = {
1041         .func                   = traceon_trigger,
1042         .print                  = traceon_trigger_print,
1043         .init                   = event_trigger_init,
1044         .free                   = event_trigger_free,
1045 };
1046
1047 static struct event_trigger_ops traceon_count_trigger_ops = {
1048         .func                   = traceon_count_trigger,
1049         .print                  = traceon_trigger_print,
1050         .init                   = event_trigger_init,
1051         .free                   = event_trigger_free,
1052 };
1053
1054 static struct event_trigger_ops traceoff_trigger_ops = {
1055         .func                   = traceoff_trigger,
1056         .print                  = traceoff_trigger_print,
1057         .init                   = event_trigger_init,
1058         .free                   = event_trigger_free,
1059 };
1060
1061 static struct event_trigger_ops traceoff_count_trigger_ops = {
1062         .func                   = traceoff_count_trigger,
1063         .print                  = traceoff_trigger_print,
1064         .init                   = event_trigger_init,
1065         .free                   = event_trigger_free,
1066 };
1067
1068 static struct event_trigger_ops *
1069 onoff_get_trigger_ops(char *cmd, char *param)
1070 {
1071         struct event_trigger_ops *ops;
1072
1073         /* we register both traceon and traceoff to this callback */
1074         if (strcmp(cmd, "traceon") == 0)
1075                 ops = param ? &traceon_count_trigger_ops :
1076                         &traceon_trigger_ops;
1077         else
1078                 ops = param ? &traceoff_count_trigger_ops :
1079                         &traceoff_trigger_ops;
1080
1081         return ops;
1082 }
1083
1084 static struct event_command trigger_traceon_cmd = {
1085         .name                   = "traceon",
1086         .trigger_type           = ETT_TRACE_ONOFF,
1087         .func                   = event_trigger_callback,
1088         .reg                    = register_trigger,
1089         .unreg                  = unregister_trigger,
1090         .get_trigger_ops        = onoff_get_trigger_ops,
1091         .set_filter             = set_trigger_filter,
1092 };
1093
1094 static struct event_command trigger_traceoff_cmd = {
1095         .name                   = "traceoff",
1096         .trigger_type           = ETT_TRACE_ONOFF,
1097         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1098         .func                   = event_trigger_callback,
1099         .reg                    = register_trigger,
1100         .unreg                  = unregister_trigger,
1101         .get_trigger_ops        = onoff_get_trigger_ops,
1102         .set_filter             = set_trigger_filter,
1103 };
1104
1105 #ifdef CONFIG_TRACER_SNAPSHOT
1106 static void
1107 snapshot_trigger(struct event_trigger_data *data, void *rec,
1108                  struct ring_buffer_event *event)
1109 {
1110         struct trace_event_file *file = data->private_data;
1111
1112         if (file)
1113                 tracing_snapshot_instance(file->tr);
1114         else
1115                 tracing_snapshot();
1116 }
1117
1118 static void
1119 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1120                        struct ring_buffer_event *event)
1121 {
1122         if (!data->count)
1123                 return;
1124
1125         if (data->count != -1)
1126                 (data->count)--;
1127
1128         snapshot_trigger(data, rec, event);
1129 }
1130
1131 static int
1132 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1133                           struct event_trigger_data *data,
1134                           struct trace_event_file *file)
1135 {
1136         if (tracing_alloc_snapshot_instance(file->tr) != 0)
1137                 return 0;
1138
1139         return register_trigger(glob, ops, data, file);
1140 }
1141
1142 static int
1143 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1144                        struct event_trigger_data *data)
1145 {
1146         return event_trigger_print("snapshot", m, (void *)data->count,
1147                                    data->filter_str);
1148 }
1149
1150 static struct event_trigger_ops snapshot_trigger_ops = {
1151         .func                   = snapshot_trigger,
1152         .print                  = snapshot_trigger_print,
1153         .init                   = event_trigger_init,
1154         .free                   = event_trigger_free,
1155 };
1156
1157 static struct event_trigger_ops snapshot_count_trigger_ops = {
1158         .func                   = snapshot_count_trigger,
1159         .print                  = snapshot_trigger_print,
1160         .init                   = event_trigger_init,
1161         .free                   = event_trigger_free,
1162 };
1163
1164 static struct event_trigger_ops *
1165 snapshot_get_trigger_ops(char *cmd, char *param)
1166 {
1167         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1168 }
1169
1170 static struct event_command trigger_snapshot_cmd = {
1171         .name                   = "snapshot",
1172         .trigger_type           = ETT_SNAPSHOT,
1173         .func                   = event_trigger_callback,
1174         .reg                    = register_snapshot_trigger,
1175         .unreg                  = unregister_trigger,
1176         .get_trigger_ops        = snapshot_get_trigger_ops,
1177         .set_filter             = set_trigger_filter,
1178 };
1179
1180 static __init int register_trigger_snapshot_cmd(void)
1181 {
1182         int ret;
1183
1184         ret = register_event_command(&trigger_snapshot_cmd);
1185         WARN_ON(ret < 0);
1186
1187         return ret;
1188 }
1189 #else
1190 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1191 #endif /* CONFIG_TRACER_SNAPSHOT */
1192
1193 #ifdef CONFIG_STACKTRACE
1194 #ifdef CONFIG_UNWINDER_ORC
1195 /* Skip 2:
1196  *   event_triggers_post_call()
1197  *   trace_event_raw_event_xxx()
1198  */
1199 # define STACK_SKIP 2
1200 #else
1201 /*
1202  * Skip 4:
1203  *   stacktrace_trigger()
1204  *   event_triggers_post_call()
1205  *   trace_event_buffer_commit()
1206  *   trace_event_raw_event_xxx()
1207  */
1208 #define STACK_SKIP 4
1209 #endif
1210
1211 static void
1212 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1213                    struct ring_buffer_event *event)
1214 {
1215         struct trace_event_file *file = data->private_data;
1216         unsigned long flags;
1217
1218         if (file) {
1219                 local_save_flags(flags);
1220                 __trace_stack(file->tr, flags, STACK_SKIP, preempt_count());
1221         } else
1222                 trace_dump_stack(STACK_SKIP);
1223 }
1224
1225 static void
1226 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1227                          struct ring_buffer_event *event)
1228 {
1229         if (!data->count)
1230                 return;
1231
1232         if (data->count != -1)
1233                 (data->count)--;
1234
1235         stacktrace_trigger(data, rec, event);
1236 }
1237
1238 static int
1239 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1240                          struct event_trigger_data *data)
1241 {
1242         return event_trigger_print("stacktrace", m, (void *)data->count,
1243                                    data->filter_str);
1244 }
1245
1246 static struct event_trigger_ops stacktrace_trigger_ops = {
1247         .func                   = stacktrace_trigger,
1248         .print                  = stacktrace_trigger_print,
1249         .init                   = event_trigger_init,
1250         .free                   = event_trigger_free,
1251 };
1252
1253 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1254         .func                   = stacktrace_count_trigger,
1255         .print                  = stacktrace_trigger_print,
1256         .init                   = event_trigger_init,
1257         .free                   = event_trigger_free,
1258 };
1259
1260 static struct event_trigger_ops *
1261 stacktrace_get_trigger_ops(char *cmd, char *param)
1262 {
1263         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1264 }
1265
1266 static struct event_command trigger_stacktrace_cmd = {
1267         .name                   = "stacktrace",
1268         .trigger_type           = ETT_STACKTRACE,
1269         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1270         .func                   = event_trigger_callback,
1271         .reg                    = register_trigger,
1272         .unreg                  = unregister_trigger,
1273         .get_trigger_ops        = stacktrace_get_trigger_ops,
1274         .set_filter             = set_trigger_filter,
1275 };
1276
1277 static __init int register_trigger_stacktrace_cmd(void)
1278 {
1279         int ret;
1280
1281         ret = register_event_command(&trigger_stacktrace_cmd);
1282         WARN_ON(ret < 0);
1283
1284         return ret;
1285 }
1286 #else
1287 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1288 #endif /* CONFIG_STACKTRACE */
1289
1290 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1291 {
1292         unregister_event_command(&trigger_traceon_cmd);
1293         unregister_event_command(&trigger_traceoff_cmd);
1294 }
1295
1296 static void
1297 event_enable_trigger(struct event_trigger_data *data, void *rec,
1298                      struct ring_buffer_event *event)
1299 {
1300         struct enable_trigger_data *enable_data = data->private_data;
1301
1302         if (enable_data->enable)
1303                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1304         else
1305                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1306 }
1307
1308 static void
1309 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1310                            struct ring_buffer_event *event)
1311 {
1312         struct enable_trigger_data *enable_data = data->private_data;
1313
1314         if (!data->count)
1315                 return;
1316
1317         /* Skip if the event is in a state we want to switch to */
1318         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1319                 return;
1320
1321         if (data->count != -1)
1322                 (data->count)--;
1323
1324         event_enable_trigger(data, rec, event);
1325 }
1326
1327 int event_enable_trigger_print(struct seq_file *m,
1328                                struct event_trigger_ops *ops,
1329                                struct event_trigger_data *data)
1330 {
1331         struct enable_trigger_data *enable_data = data->private_data;
1332
1333         seq_printf(m, "%s:%s:%s",
1334                    enable_data->hist ?
1335                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1336                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1337                    enable_data->file->event_call->class->system,
1338                    trace_event_name(enable_data->file->event_call));
1339
1340         if (data->count == -1)
1341                 seq_puts(m, ":unlimited");
1342         else
1343                 seq_printf(m, ":count=%ld", data->count);
1344
1345         if (data->filter_str)
1346                 seq_printf(m, " if %s\n", data->filter_str);
1347         else
1348                 seq_putc(m, '\n');
1349
1350         return 0;
1351 }
1352
1353 void event_enable_trigger_free(struct event_trigger_ops *ops,
1354                                struct event_trigger_data *data)
1355 {
1356         struct enable_trigger_data *enable_data = data->private_data;
1357
1358         if (WARN_ON_ONCE(data->ref <= 0))
1359                 return;
1360
1361         data->ref--;
1362         if (!data->ref) {
1363                 /* Remove the SOFT_MODE flag */
1364                 trace_event_enable_disable(enable_data->file, 0, 1);
1365                 module_put(enable_data->file->event_call->mod);
1366                 trigger_data_free(data);
1367                 kfree(enable_data);
1368         }
1369 }
1370
1371 static struct event_trigger_ops event_enable_trigger_ops = {
1372         .func                   = event_enable_trigger,
1373         .print                  = event_enable_trigger_print,
1374         .init                   = event_trigger_init,
1375         .free                   = event_enable_trigger_free,
1376 };
1377
1378 static struct event_trigger_ops event_enable_count_trigger_ops = {
1379         .func                   = event_enable_count_trigger,
1380         .print                  = event_enable_trigger_print,
1381         .init                   = event_trigger_init,
1382         .free                   = event_enable_trigger_free,
1383 };
1384
1385 static struct event_trigger_ops event_disable_trigger_ops = {
1386         .func                   = event_enable_trigger,
1387         .print                  = event_enable_trigger_print,
1388         .init                   = event_trigger_init,
1389         .free                   = event_enable_trigger_free,
1390 };
1391
1392 static struct event_trigger_ops event_disable_count_trigger_ops = {
1393         .func                   = event_enable_count_trigger,
1394         .print                  = event_enable_trigger_print,
1395         .init                   = event_trigger_init,
1396         .free                   = event_enable_trigger_free,
1397 };
1398
1399 int event_enable_trigger_func(struct event_command *cmd_ops,
1400                               struct trace_event_file *file,
1401                               char *glob, char *cmd, char *param)
1402 {
1403         struct trace_event_file *event_enable_file;
1404         struct enable_trigger_data *enable_data;
1405         struct event_trigger_data *trigger_data;
1406         struct event_trigger_ops *trigger_ops;
1407         struct trace_array *tr = file->tr;
1408         const char *system;
1409         const char *event;
1410         bool hist = false;
1411         char *trigger;
1412         char *number;
1413         bool enable;
1414         int ret;
1415
1416         if (!param)
1417                 return -EINVAL;
1418
1419         /* separate the trigger from the filter (s:e:n [if filter]) */
1420         trigger = strsep(&param, " \t");
1421         if (!trigger)
1422                 return -EINVAL;
1423         if (param) {
1424                 param = skip_spaces(param);
1425                 if (!*param)
1426                         param = NULL;
1427         }
1428
1429         system = strsep(&trigger, ":");
1430         if (!trigger)
1431                 return -EINVAL;
1432
1433         event = strsep(&trigger, ":");
1434
1435         ret = -EINVAL;
1436         event_enable_file = find_event_file(tr, system, event);
1437         if (!event_enable_file)
1438                 goto out;
1439
1440 #ifdef CONFIG_HIST_TRIGGERS
1441         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1442                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1443
1444         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1445                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1446 #else
1447         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1448 #endif
1449         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1450
1451         ret = -ENOMEM;
1452         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1453         if (!trigger_data)
1454                 goto out;
1455
1456         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1457         if (!enable_data) {
1458                 kfree(trigger_data);
1459                 goto out;
1460         }
1461
1462         trigger_data->count = -1;
1463         trigger_data->ops = trigger_ops;
1464         trigger_data->cmd_ops = cmd_ops;
1465         INIT_LIST_HEAD(&trigger_data->list);
1466         RCU_INIT_POINTER(trigger_data->filter, NULL);
1467
1468         enable_data->hist = hist;
1469         enable_data->enable = enable;
1470         enable_data->file = event_enable_file;
1471         trigger_data->private_data = enable_data;
1472
1473         if (glob[0] == '!') {
1474                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1475                 kfree(trigger_data);
1476                 kfree(enable_data);
1477                 ret = 0;
1478                 goto out;
1479         }
1480
1481         /* Up the trigger_data count to make sure nothing frees it on failure */
1482         event_trigger_init(trigger_ops, trigger_data);
1483
1484         if (trigger) {
1485                 number = strsep(&trigger, ":");
1486
1487                 ret = -EINVAL;
1488                 if (!strlen(number))
1489                         goto out_free;
1490
1491                 /*
1492                  * We use the callback data field (which is a pointer)
1493                  * as our counter.
1494                  */
1495                 ret = kstrtoul(number, 0, &trigger_data->count);
1496                 if (ret)
1497                         goto out_free;
1498         }
1499
1500         if (!param) /* if param is non-empty, it's supposed to be a filter */
1501                 goto out_reg;
1502
1503         if (!cmd_ops->set_filter)
1504                 goto out_reg;
1505
1506         ret = cmd_ops->set_filter(param, trigger_data, file);
1507         if (ret < 0)
1508                 goto out_free;
1509
1510  out_reg:
1511         /* Don't let event modules unload while probe registered */
1512         ret = try_module_get(event_enable_file->event_call->mod);
1513         if (!ret) {
1514                 ret = -EBUSY;
1515                 goto out_free;
1516         }
1517
1518         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1519         if (ret < 0)
1520                 goto out_put;
1521         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1522         /*
1523          * The above returns on success the # of functions enabled,
1524          * but if it didn't find any functions it returns zero.
1525          * Consider no functions a failure too.
1526          */
1527         if (!ret) {
1528                 ret = -ENOENT;
1529                 goto out_disable;
1530         } else if (ret < 0)
1531                 goto out_disable;
1532         /* Just return zero, not the number of enabled functions */
1533         ret = 0;
1534         event_trigger_free(trigger_ops, trigger_data);
1535  out:
1536         return ret;
1537
1538  out_disable:
1539         trace_event_enable_disable(event_enable_file, 0, 1);
1540  out_put:
1541         module_put(event_enable_file->event_call->mod);
1542  out_free:
1543         if (cmd_ops->set_filter)
1544                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1545         event_trigger_free(trigger_ops, trigger_data);
1546         kfree(enable_data);
1547         goto out;
1548 }
1549
1550 int event_enable_register_trigger(char *glob,
1551                                   struct event_trigger_ops *ops,
1552                                   struct event_trigger_data *data,
1553                                   struct trace_event_file *file)
1554 {
1555         struct enable_trigger_data *enable_data = data->private_data;
1556         struct enable_trigger_data *test_enable_data;
1557         struct event_trigger_data *test;
1558         int ret = 0;
1559
1560         lockdep_assert_held(&event_mutex);
1561
1562         list_for_each_entry(test, &file->triggers, list) {
1563                 test_enable_data = test->private_data;
1564                 if (test_enable_data &&
1565                     (test->cmd_ops->trigger_type ==
1566                      data->cmd_ops->trigger_type) &&
1567                     (test_enable_data->file == enable_data->file)) {
1568                         ret = -EEXIST;
1569                         goto out;
1570                 }
1571         }
1572
1573         if (data->ops->init) {
1574                 ret = data->ops->init(data->ops, data);
1575                 if (ret < 0)
1576                         goto out;
1577         }
1578
1579         list_add_rcu(&data->list, &file->triggers);
1580         ret++;
1581
1582         update_cond_flag(file);
1583         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1584                 list_del_rcu(&data->list);
1585                 update_cond_flag(file);
1586                 ret--;
1587         }
1588 out:
1589         return ret;
1590 }
1591
1592 void event_enable_unregister_trigger(char *glob,
1593                                      struct event_trigger_ops *ops,
1594                                      struct event_trigger_data *test,
1595                                      struct trace_event_file *file)
1596 {
1597         struct enable_trigger_data *test_enable_data = test->private_data;
1598         struct enable_trigger_data *enable_data;
1599         struct event_trigger_data *data;
1600         bool unregistered = false;
1601
1602         lockdep_assert_held(&event_mutex);
1603
1604         list_for_each_entry(data, &file->triggers, list) {
1605                 enable_data = data->private_data;
1606                 if (enable_data &&
1607                     (data->cmd_ops->trigger_type ==
1608                      test->cmd_ops->trigger_type) &&
1609                     (enable_data->file == test_enable_data->file)) {
1610                         unregistered = true;
1611                         list_del_rcu(&data->list);
1612                         trace_event_trigger_enable_disable(file, 0);
1613                         update_cond_flag(file);
1614                         break;
1615                 }
1616         }
1617
1618         if (unregistered && data->ops->free)
1619                 data->ops->free(data->ops, data);
1620 }
1621
1622 static struct event_trigger_ops *
1623 event_enable_get_trigger_ops(char *cmd, char *param)
1624 {
1625         struct event_trigger_ops *ops;
1626         bool enable;
1627
1628 #ifdef CONFIG_HIST_TRIGGERS
1629         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1630                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1631 #else
1632         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1633 #endif
1634         if (enable)
1635                 ops = param ? &event_enable_count_trigger_ops :
1636                         &event_enable_trigger_ops;
1637         else
1638                 ops = param ? &event_disable_count_trigger_ops :
1639                         &event_disable_trigger_ops;
1640
1641         return ops;
1642 }
1643
1644 static struct event_command trigger_enable_cmd = {
1645         .name                   = ENABLE_EVENT_STR,
1646         .trigger_type           = ETT_EVENT_ENABLE,
1647         .func                   = event_enable_trigger_func,
1648         .reg                    = event_enable_register_trigger,
1649         .unreg                  = event_enable_unregister_trigger,
1650         .get_trigger_ops        = event_enable_get_trigger_ops,
1651         .set_filter             = set_trigger_filter,
1652 };
1653
1654 static struct event_command trigger_disable_cmd = {
1655         .name                   = DISABLE_EVENT_STR,
1656         .trigger_type           = ETT_EVENT_ENABLE,
1657         .func                   = event_enable_trigger_func,
1658         .reg                    = event_enable_register_trigger,
1659         .unreg                  = event_enable_unregister_trigger,
1660         .get_trigger_ops        = event_enable_get_trigger_ops,
1661         .set_filter             = set_trigger_filter,
1662 };
1663
1664 static __init void unregister_trigger_enable_disable_cmds(void)
1665 {
1666         unregister_event_command(&trigger_enable_cmd);
1667         unregister_event_command(&trigger_disable_cmd);
1668 }
1669
1670 static __init int register_trigger_enable_disable_cmds(void)
1671 {
1672         int ret;
1673
1674         ret = register_event_command(&trigger_enable_cmd);
1675         if (WARN_ON(ret < 0))
1676                 return ret;
1677         ret = register_event_command(&trigger_disable_cmd);
1678         if (WARN_ON(ret < 0))
1679                 unregister_trigger_enable_disable_cmds();
1680
1681         return ret;
1682 }
1683
1684 static __init int register_trigger_traceon_traceoff_cmds(void)
1685 {
1686         int ret;
1687
1688         ret = register_event_command(&trigger_traceon_cmd);
1689         if (WARN_ON(ret < 0))
1690                 return ret;
1691         ret = register_event_command(&trigger_traceoff_cmd);
1692         if (WARN_ON(ret < 0))
1693                 unregister_trigger_traceon_traceoff_cmds();
1694
1695         return ret;
1696 }
1697
1698 __init int register_trigger_cmds(void)
1699 {
1700         register_trigger_traceon_traceoff_cmds();
1701         register_trigger_snapshot_cmd();
1702         register_trigger_stacktrace_cmd();
1703         register_trigger_enable_disable_cmds();
1704         register_trigger_hist_enable_disable_cmds();
1705         register_trigger_hist_cmd();
1706
1707         return 0;
1708 }