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