linux/kernel/trace/trace_events_trigger.c
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   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
  17static LIST_HEAD(trigger_commands);
  18static DEFINE_MUTEX(trigger_cmd_mutex);
  19
  20void 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 */
  55enum event_trigger_type
  56event_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}
  84EXPORT_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 */
  98void
  99event_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}
 111EXPORT_SYMBOL_GPL(event_triggers_post_call);
 112
 113#define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 114
 115static 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
 125static 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
 141static void trigger_stop(struct seq_file *m, void *t)
 142{
 143        mutex_unlock(&event_mutex);
 144}
 145
 146static 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
 168static 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
 175static 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
 216static 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
 238static 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
 278static 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
 290static ssize_t
 291event_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
 297static int
 298event_trigger_open(struct inode *inode, struct file *filp)
 299{
 300        /* Checks for tracefs lockdown */
 301        return event_trigger_regex_open(inode, filp);
 302}
 303
 304static int
 305event_trigger_release(struct inode *inode, struct file *file)
 306{
 307        return event_trigger_regex_release(inode, file);
 308}
 309
 310const 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 */
 378static int
 379event_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 */
 411int 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 */
 428static void
 429event_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
 440int 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 */
 473void
 474clear_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 */
 499void update_cond_flag(struct trace_event_file *file)
 500{
 501        struct event_trigger_data *data;
 502        bool set_cond = false;
 503
 504        list_for_each_entry_rcu(data, &file->triggers, list) {
 505                if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 506                    event_command_needs_rec(data->cmd_ops)) {
 507                        set_cond = true;
 508                        break;
 509                }
 510        }
 511
 512        if (set_cond)
 513                set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 514        else
 515                clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 516}
 517
 518/**
 519 * register_trigger - Generic event_command @reg implementation
 520 * @glob: The raw string used to register the trigger
 521 * @ops: The trigger ops associated with the trigger
 522 * @data: Trigger-specific data to associate with the trigger
 523 * @file: The trace_event_file associated with the event
 524 *
 525 * Common implementation for event trigger registration.
 526 *
 527 * Usually used directly as the @reg method in event command
 528 * implementations.
 529 *
 530 * Return: 0 on success, errno otherwise
 531 */
 532static int register_trigger(char *glob, struct event_trigger_ops *ops,
 533                            struct event_trigger_data *data,
 534                            struct trace_event_file *file)
 535{
 536        struct event_trigger_data *test;
 537        int ret = 0;
 538
 539        list_for_each_entry_rcu(test, &file->triggers, list) {
 540                if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 541                        ret = -EEXIST;
 542                        goto out;
 543                }
 544        }
 545
 546        if (data->ops->init) {
 547                ret = data->ops->init(data->ops, data);
 548                if (ret < 0)
 549                        goto out;
 550        }
 551
 552        list_add_rcu(&data->list, &file->triggers);
 553        ret++;
 554
 555        update_cond_flag(file);
 556        if (trace_event_trigger_enable_disable(file, 1) < 0) {
 557                list_del_rcu(&data->list);
 558                update_cond_flag(file);
 559                ret--;
 560        }
 561out:
 562        return ret;
 563}
 564
 565/**
 566 * unregister_trigger - Generic event_command @unreg implementation
 567 * @glob: The raw string used to register the trigger
 568 * @ops: The trigger ops associated with the trigger
 569 * @test: Trigger-specific data used to find the trigger to remove
 570 * @file: The trace_event_file associated with the event
 571 *
 572 * Common implementation for event trigger unregistration.
 573 *
 574 * Usually used directly as the @unreg method in event command
 575 * implementations.
 576 */
 577static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 578                               struct event_trigger_data *test,
 579                               struct trace_event_file *file)
 580{
 581        struct event_trigger_data *data;
 582        bool unregistered = false;
 583
 584        list_for_each_entry_rcu(data, &file->triggers, list) {
 585                if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 586                        unregistered = true;
 587                        list_del_rcu(&data->list);
 588                        trace_event_trigger_enable_disable(file, 0);
 589                        update_cond_flag(file);
 590                        break;
 591                }
 592        }
 593
 594        if (unregistered && data->ops->free)
 595                data->ops->free(data->ops, data);
 596}
 597
 598/**
 599 * event_trigger_callback - Generic event_command @func implementation
 600 * @cmd_ops: The command ops, used for trigger registration
 601 * @file: The trace_event_file associated with the event
 602 * @glob: The raw string used to register the trigger
 603 * @cmd: The cmd portion of the string used to register the trigger
 604 * @param: The params portion of the string used to register the trigger
 605 *
 606 * Common implementation for event command parsing and trigger
 607 * instantiation.
 608 *
 609 * Usually used directly as the @func method in event command
 610 * implementations.
 611 *
 612 * Return: 0 on success, errno otherwise
 613 */
 614static int
 615event_trigger_callback(struct event_command *cmd_ops,
 616                       struct trace_event_file *file,
 617                       char *glob, char *cmd, char *param)
 618{
 619        struct event_trigger_data *trigger_data;
 620        struct event_trigger_ops *trigger_ops;
 621        char *trigger = NULL;
 622        char *number;
 623        int ret;
 624
 625        /* separate the trigger from the filter (t:n [if filter]) */
 626        if (param && isdigit(param[0]))
 627                trigger = strsep(&param, " \t");
 628
 629        trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 630
 631        ret = -ENOMEM;
 632        trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 633        if (!trigger_data)
 634                goto out;
 635
 636        trigger_data->count = -1;
 637        trigger_data->ops = trigger_ops;
 638        trigger_data->cmd_ops = cmd_ops;
 639        trigger_data->private_data = file;
 640        INIT_LIST_HEAD(&trigger_data->list);
 641        INIT_LIST_HEAD(&trigger_data->named_list);
 642
 643        if (glob[0] == '!') {
 644                cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 645                kfree(trigger_data);
 646                ret = 0;
 647                goto out;
 648        }
 649
 650        if (trigger) {
 651                number = strsep(&trigger, ":");
 652
 653                ret = -EINVAL;
 654                if (!strlen(number))
 655                        goto out_free;
 656
 657                /*
 658                 * We use the callback data field (which is a pointer)
 659                 * as our counter.
 660                 */
 661                ret = kstrtoul(number, 0, &trigger_data->count);
 662                if (ret)
 663                        goto out_free;
 664        }
 665
 666        if (!param) /* if param is non-empty, it's supposed to be a filter */
 667                goto out_reg;
 668
 669        if (!cmd_ops->set_filter)
 670                goto out_reg;
 671
 672        ret = cmd_ops->set_filter(param, trigger_data, file);
 673        if (ret < 0)
 674                goto out_free;
 675
 676 out_reg:
 677        /* Up the trigger_data count to make sure reg doesn't free it on failure */
 678        event_trigger_init(trigger_ops, trigger_data);
 679        ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 680        /*
 681         * The above returns on success the # of functions enabled,
 682         * but if it didn't find any functions it returns zero.
 683         * Consider no functions a failure too.
 684         */
 685        if (!ret) {
 686                cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 687                ret = -ENOENT;
 688        } else if (ret > 0)
 689                ret = 0;
 690
 691        /* Down the counter of trigger_data or free it if not used anymore */
 692        event_trigger_free(trigger_ops, trigger_data);
 693 out:
 694        return ret;
 695
 696 out_free:
 697        if (cmd_ops->set_filter)
 698                cmd_ops->set_filter(NULL, trigger_data, NULL);
 699        kfree(trigger_data);
 700        goto out;
 701}
 702
 703/**
 704 * set_trigger_filter - Generic event_command @set_filter implementation
 705 * @filter_str: The filter string for the trigger, NULL to remove filter
 706 * @trigger_data: Trigger-specific data
 707 * @file: The trace_event_file associated with the event
 708 *
 709 * Common implementation for event command filter parsing and filter
 710 * instantiation.
 711 *
 712 * Usually used directly as the @set_filter method in event command
 713 * implementations.
 714 *
 715 * Also used to remove a filter (if filter_str = NULL).
 716 *
 717 * Return: 0 on success, errno otherwise
 718 */
 719int set_trigger_filter(char *filter_str,
 720                       struct event_trigger_data *trigger_data,
 721                       struct trace_event_file *file)
 722{
 723        struct event_trigger_data *data = trigger_data;
 724        struct event_filter *filter = NULL, *tmp;
 725        int ret = -EINVAL;
 726        char *s;
 727
 728        if (!filter_str) /* clear the current filter */
 729                goto assign;
 730
 731        s = strsep(&filter_str, " \t");
 732
 733        if (!strlen(s) || strcmp(s, "if") != 0)
 734                goto out;
 735
 736        if (!filter_str)
 737                goto out;
 738
 739        /* The filter is for the 'trigger' event, not the triggered event */
 740        ret = create_event_filter(file->tr, file->event_call,
 741                                  filter_str, false, &filter);
 742        /*
 743         * If create_event_filter() fails, filter still needs to be freed.
 744         * Which the calling code will do with data->filter.
 745         */
 746 assign:
 747        tmp = rcu_access_pointer(data->filter);
 748
 749        rcu_assign_pointer(data->filter, filter);
 750
 751        if (tmp) {
 752                /* Make sure the call is done with the filter */
 753                tracepoint_synchronize_unregister();
 754                free_event_filter(tmp);
 755        }
 756
 757        kfree(data->filter_str);
 758        data->filter_str = NULL;
 759
 760        if (filter_str) {
 761                data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 762                if (!data->filter_str) {
 763                        free_event_filter(rcu_access_pointer(data->filter));
 764                        data->filter = NULL;
 765                        ret = -ENOMEM;
 766                }
 767        }
 768 out:
 769        return ret;
 770}
 771
 772static LIST_HEAD(named_triggers);
 773
 774/**
 775 * find_named_trigger - Find the common named trigger associated with @name
 776 * @name: The name of the set of named triggers to find the common data for
 777 *
 778 * Named triggers are sets of triggers that share a common set of
 779 * trigger data.  The first named trigger registered with a given name
 780 * owns the common trigger data that the others subsequently
 781 * registered with the same name will reference.  This function
 782 * returns the common trigger data associated with that first
 783 * registered instance.
 784 *
 785 * Return: the common trigger data for the given named trigger on
 786 * success, NULL otherwise.
 787 */
 788struct event_trigger_data *find_named_trigger(const char *name)
 789{
 790        struct event_trigger_data *data;
 791
 792        if (!name)
 793                return NULL;
 794
 795        list_for_each_entry(data, &named_triggers, named_list) {
 796                if (data->named_data)
 797                        continue;
 798                if (strcmp(data->name, name) == 0)
 799                        return data;
 800        }
 801
 802        return NULL;
 803}
 804
 805/**
 806 * is_named_trigger - determine if a given trigger is a named trigger
 807 * @test: The trigger data to test
 808 *
 809 * Return: true if 'test' is a named trigger, false otherwise.
 810 */
 811bool is_named_trigger(struct event_trigger_data *test)
 812{
 813        struct event_trigger_data *data;
 814
 815        list_for_each_entry(data, &named_triggers, named_list) {
 816                if (test == data)
 817                        return true;
 818        }
 819
 820        return false;
 821}
 822
 823/**
 824 * save_named_trigger - save the trigger in the named trigger list
 825 * @name: The name of the named trigger set
 826 * @data: The trigger data to save
 827 *
 828 * Return: 0 if successful, negative error otherwise.
 829 */
 830int save_named_trigger(const char *name, struct event_trigger_data *data)
 831{
 832        data->name = kstrdup(name, GFP_KERNEL);
 833        if (!data->name)
 834                return -ENOMEM;
 835
 836        list_add(&data->named_list, &named_triggers);
 837
 838        return 0;
 839}
 840
 841/**
 842 * del_named_trigger - delete a trigger from the named trigger list
 843 * @data: The trigger data to delete
 844 */
 845void del_named_trigger(struct event_trigger_data *data)
 846{
 847        kfree(data->name);
 848        data->name = NULL;
 849
 850        list_del(&data->named_list);
 851}
 852
 853static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 854{
 855        struct event_trigger_data *test;
 856
 857        list_for_each_entry(test, &named_triggers, named_list) {
 858                if (strcmp(test->name, data->name) == 0) {
 859                        if (pause) {
 860                                test->paused_tmp = test->paused;
 861                                test->paused = true;
 862                        } else {
 863                                test->paused = test->paused_tmp;
 864                        }
 865                }
 866        }
 867}
 868
 869/**
 870 * pause_named_trigger - Pause all named triggers with the same name
 871 * @data: The trigger data of a named trigger to pause
 872 *
 873 * Pauses a named trigger along with all other triggers having the
 874 * same name.  Because named triggers share a common set of data,
 875 * pausing only one is meaningless, so pausing one named trigger needs
 876 * to pause all triggers with the same name.
 877 */
 878void pause_named_trigger(struct event_trigger_data *data)
 879{
 880        __pause_named_trigger(data, true);
 881}
 882
 883/**
 884 * unpause_named_trigger - Un-pause all named triggers with the same name
 885 * @data: The trigger data of a named trigger to unpause
 886 *
 887 * Un-pauses a named trigger along with all other triggers having the
 888 * same name.  Because named triggers share a common set of data,
 889 * unpausing only one is meaningless, so unpausing one named trigger
 890 * needs to unpause all triggers with the same name.
 891 */
 892void unpause_named_trigger(struct event_trigger_data *data)
 893{
 894        __pause_named_trigger(data, false);
 895}
 896
 897/**
 898 * set_named_trigger_data - Associate common named trigger data
 899 * @data: The trigger data of a named trigger to unpause
 900 *
 901 * Named triggers are sets of triggers that share a common set of
 902 * trigger data.  The first named trigger registered with a given name
 903 * owns the common trigger data that the others subsequently
 904 * registered with the same name will reference.  This function
 905 * associates the common trigger data from the first trigger with the
 906 * given trigger.
 907 */
 908void set_named_trigger_data(struct event_trigger_data *data,
 909                            struct event_trigger_data *named_data)
 910{
 911        data->named_data = named_data;
 912}
 913
 914struct event_trigger_data *
 915get_named_trigger_data(struct event_trigger_data *data)
 916{
 917        return data->named_data;
 918}
 919
 920static void
 921traceon_trigger(struct event_trigger_data *data, void *rec,
 922                struct ring_buffer_event *event)
 923{
 924        if (tracing_is_on())
 925                return;
 926
 927        tracing_on();
 928}
 929
 930static void
 931traceon_count_trigger(struct event_trigger_data *data, void *rec,
 932                      struct ring_buffer_event *event)
 933{
 934        if (tracing_is_on())
 935                return;
 936
 937        if (!data->count)
 938                return;
 939
 940        if (data->count != -1)
 941                (data->count)--;
 942
 943        tracing_on();
 944}
 945
 946static void
 947traceoff_trigger(struct event_trigger_data *data, void *rec,
 948                 struct ring_buffer_event *event)
 949{
 950        if (!tracing_is_on())
 951                return;
 952
 953        tracing_off();
 954}
 955
 956static void
 957traceoff_count_trigger(struct event_trigger_data *data, void *rec,
 958                       struct ring_buffer_event *event)
 959{
 960        if (!tracing_is_on())
 961                return;
 962
 963        if (!data->count)
 964                return;
 965
 966        if (data->count != -1)
 967                (data->count)--;
 968
 969        tracing_off();
 970}
 971
 972static int
 973traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 974                      struct event_trigger_data *data)
 975{
 976        return event_trigger_print("traceon", m, (void *)data->count,
 977                                   data->filter_str);
 978}
 979
 980static int
 981traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 982                       struct event_trigger_data *data)
 983{
 984        return event_trigger_print("traceoff", m, (void *)data->count,
 985                                   data->filter_str);
 986}
 987
 988static struct event_trigger_ops traceon_trigger_ops = {
 989        .func                   = traceon_trigger,
 990        .print                  = traceon_trigger_print,
 991        .init                   = event_trigger_init,
 992        .free                   = event_trigger_free,
 993};
 994
 995static struct event_trigger_ops traceon_count_trigger_ops = {
 996        .func                   = traceon_count_trigger,
 997        .print                  = traceon_trigger_print,
 998        .init                   = event_trigger_init,
 999        .free                   = event_trigger_free,
1000};
1001
1002static struct event_trigger_ops traceoff_trigger_ops = {
1003        .func                   = traceoff_trigger,
1004        .print                  = traceoff_trigger_print,
1005        .init                   = event_trigger_init,
1006        .free                   = event_trigger_free,
1007};
1008
1009static struct event_trigger_ops traceoff_count_trigger_ops = {
1010        .func                   = traceoff_count_trigger,
1011        .print                  = traceoff_trigger_print,
1012        .init                   = event_trigger_init,
1013        .free                   = event_trigger_free,
1014};
1015
1016static struct event_trigger_ops *
1017onoff_get_trigger_ops(char *cmd, char *param)
1018{
1019        struct event_trigger_ops *ops;
1020
1021        /* we register both traceon and traceoff to this callback */
1022        if (strcmp(cmd, "traceon") == 0)
1023                ops = param ? &traceon_count_trigger_ops :
1024                        &traceon_trigger_ops;
1025        else
1026                ops = param ? &traceoff_count_trigger_ops :
1027                        &traceoff_trigger_ops;
1028
1029        return ops;
1030}
1031
1032static struct event_command trigger_traceon_cmd = {
1033        .name                   = "traceon",
1034        .trigger_type           = ETT_TRACE_ONOFF,
1035        .func                   = event_trigger_callback,
1036        .reg                    = register_trigger,
1037        .unreg                  = unregister_trigger,
1038        .get_trigger_ops        = onoff_get_trigger_ops,
1039        .set_filter             = set_trigger_filter,
1040};
1041
1042static struct event_command trigger_traceoff_cmd = {
1043        .name                   = "traceoff",
1044        .trigger_type           = ETT_TRACE_ONOFF,
1045        .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1046        .func                   = event_trigger_callback,
1047        .reg                    = register_trigger,
1048        .unreg                  = unregister_trigger,
1049        .get_trigger_ops        = onoff_get_trigger_ops,
1050        .set_filter             = set_trigger_filter,
1051};
1052
1053#ifdef CONFIG_TRACER_SNAPSHOT
1054static void
1055snapshot_trigger(struct event_trigger_data *data, void *rec,
1056                 struct ring_buffer_event *event)
1057{
1058        struct trace_event_file *file = data->private_data;
1059
1060        if (file)
1061                tracing_snapshot_instance(file->tr);
1062        else
1063                tracing_snapshot();
1064}
1065
1066static void
1067snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1068                       struct ring_buffer_event *event)
1069{
1070        if (!data->count)
1071                return;
1072
1073        if (data->count != -1)
1074                (data->count)--;
1075
1076        snapshot_trigger(data, rec, event);
1077}
1078
1079static int
1080register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1081                          struct event_trigger_data *data,
1082                          struct trace_event_file *file)
1083{
1084        int ret = register_trigger(glob, ops, data, file);
1085
1086        if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
1087                unregister_trigger(glob, ops, data, file);
1088                ret = 0;
1089        }
1090
1091        return ret;
1092}
1093
1094static int
1095snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1096                       struct event_trigger_data *data)
1097{
1098        return event_trigger_print("snapshot", m, (void *)data->count,
1099                                   data->filter_str);
1100}
1101
1102static struct event_trigger_ops snapshot_trigger_ops = {
1103        .func                   = snapshot_trigger,
1104        .print                  = snapshot_trigger_print,
1105        .init                   = event_trigger_init,
1106        .free                   = event_trigger_free,
1107};
1108
1109static struct event_trigger_ops snapshot_count_trigger_ops = {
1110        .func                   = snapshot_count_trigger,
1111        .print                  = snapshot_trigger_print,
1112        .init                   = event_trigger_init,
1113        .free                   = event_trigger_free,
1114};
1115
1116static struct event_trigger_ops *
1117snapshot_get_trigger_ops(char *cmd, char *param)
1118{
1119        return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1120}
1121
1122static struct event_command trigger_snapshot_cmd = {
1123        .name                   = "snapshot",
1124        .trigger_type           = ETT_SNAPSHOT,
1125        .func                   = event_trigger_callback,
1126        .reg                    = register_snapshot_trigger,
1127        .unreg                  = unregister_trigger,
1128        .get_trigger_ops        = snapshot_get_trigger_ops,
1129        .set_filter             = set_trigger_filter,
1130};
1131
1132static __init int register_trigger_snapshot_cmd(void)
1133{
1134        int ret;
1135
1136        ret = register_event_command(&trigger_snapshot_cmd);
1137        WARN_ON(ret < 0);
1138
1139        return ret;
1140}
1141#else
1142static __init int register_trigger_snapshot_cmd(void) { return 0; }
1143#endif /* CONFIG_TRACER_SNAPSHOT */
1144
1145#ifdef CONFIG_STACKTRACE
1146#ifdef CONFIG_UNWINDER_ORC
1147/* Skip 2:
1148 *   event_triggers_post_call()
1149 *   trace_event_raw_event_xxx()
1150 */
1151# define STACK_SKIP 2
1152#else
1153/*
1154 * Skip 4:
1155 *   stacktrace_trigger()
1156 *   event_triggers_post_call()
1157 *   trace_event_buffer_commit()
1158 *   trace_event_raw_event_xxx()
1159 */
1160#define STACK_SKIP 4
1161#endif
1162
1163static void
1164stacktrace_trigger(struct event_trigger_data *data, void *rec,
1165                   struct ring_buffer_event *event)
1166{
1167        trace_dump_stack(STACK_SKIP);
1168}
1169
1170static void
1171stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1172                         struct ring_buffer_event *event)
1173{
1174        if (!data->count)
1175                return;
1176
1177        if (data->count != -1)
1178                (data->count)--;
1179
1180        stacktrace_trigger(data, rec, event);
1181}
1182
1183static int
1184stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1185                         struct event_trigger_data *data)
1186{
1187        return event_trigger_print("stacktrace", m, (void *)data->count,
1188                                   data->filter_str);
1189}
1190
1191static struct event_trigger_ops stacktrace_trigger_ops = {
1192        .func                   = stacktrace_trigger,
1193        .print                  = stacktrace_trigger_print,
1194        .init                   = event_trigger_init,
1195        .free                   = event_trigger_free,
1196};
1197
1198static struct event_trigger_ops stacktrace_count_trigger_ops = {
1199        .func                   = stacktrace_count_trigger,
1200        .print                  = stacktrace_trigger_print,
1201        .init                   = event_trigger_init,
1202        .free                   = event_trigger_free,
1203};
1204
1205static struct event_trigger_ops *
1206stacktrace_get_trigger_ops(char *cmd, char *param)
1207{
1208        return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1209}
1210
1211static struct event_command trigger_stacktrace_cmd = {
1212        .name                   = "stacktrace",
1213        .trigger_type           = ETT_STACKTRACE,
1214        .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1215        .func                   = event_trigger_callback,
1216        .reg                    = register_trigger,
1217        .unreg                  = unregister_trigger,
1218        .get_trigger_ops        = stacktrace_get_trigger_ops,
1219        .set_filter             = set_trigger_filter,
1220};
1221
1222static __init int register_trigger_stacktrace_cmd(void)
1223{
1224        int ret;
1225
1226        ret = register_event_command(&trigger_stacktrace_cmd);
1227        WARN_ON(ret < 0);
1228
1229        return ret;
1230}
1231#else
1232static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1233#endif /* CONFIG_STACKTRACE */
1234
1235static __init void unregister_trigger_traceon_traceoff_cmds(void)
1236{
1237        unregister_event_command(&trigger_traceon_cmd);
1238        unregister_event_command(&trigger_traceoff_cmd);
1239}
1240
1241static void
1242event_enable_trigger(struct event_trigger_data *data, void *rec,
1243                     struct ring_buffer_event *event)
1244{
1245        struct enable_trigger_data *enable_data = data->private_data;
1246
1247        if (enable_data->enable)
1248                clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1249        else
1250                set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1251}
1252
1253static void
1254event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1255                           struct ring_buffer_event *event)
1256{
1257        struct enable_trigger_data *enable_data = data->private_data;
1258
1259        if (!data->count)
1260                return;
1261
1262        /* Skip if the event is in a state we want to switch to */
1263        if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1264                return;
1265
1266        if (data->count != -1)
1267                (data->count)--;
1268
1269        event_enable_trigger(data, rec, event);
1270}
1271
1272int event_enable_trigger_print(struct seq_file *m,
1273                               struct event_trigger_ops *ops,
1274                               struct event_trigger_data *data)
1275{
1276        struct enable_trigger_data *enable_data = data->private_data;
1277
1278        seq_printf(m, "%s:%s:%s",
1279                   enable_data->hist ?
1280                   (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1281                   (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1282                   enable_data->file->event_call->class->system,
1283                   trace_event_name(enable_data->file->event_call));
1284
1285        if (data->count == -1)
1286                seq_puts(m, ":unlimited");
1287        else
1288                seq_printf(m, ":count=%ld", data->count);
1289
1290        if (data->filter_str)
1291                seq_printf(m, " if %s\n", data->filter_str);
1292        else
1293                seq_putc(m, '\n');
1294
1295        return 0;
1296}
1297
1298void event_enable_trigger_free(struct event_trigger_ops *ops,
1299                               struct event_trigger_data *data)
1300{
1301        struct enable_trigger_data *enable_data = data->private_data;
1302
1303        if (WARN_ON_ONCE(data->ref <= 0))
1304                return;
1305
1306        data->ref--;
1307        if (!data->ref) {
1308                /* Remove the SOFT_MODE flag */
1309                trace_event_enable_disable(enable_data->file, 0, 1);
1310                module_put(enable_data->file->event_call->mod);
1311                trigger_data_free(data);
1312                kfree(enable_data);
1313        }
1314}
1315
1316static struct event_trigger_ops event_enable_trigger_ops = {
1317        .func                   = event_enable_trigger,
1318        .print                  = event_enable_trigger_print,
1319        .init                   = event_trigger_init,
1320        .free                   = event_enable_trigger_free,
1321};
1322
1323static struct event_trigger_ops event_enable_count_trigger_ops = {
1324        .func                   = event_enable_count_trigger,
1325        .print                  = event_enable_trigger_print,
1326        .init                   = event_trigger_init,
1327        .free                   = event_enable_trigger_free,
1328};
1329
1330static struct event_trigger_ops event_disable_trigger_ops = {
1331        .func                   = event_enable_trigger,
1332        .print                  = event_enable_trigger_print,
1333        .init                   = event_trigger_init,
1334        .free                   = event_enable_trigger_free,
1335};
1336
1337static struct event_trigger_ops event_disable_count_trigger_ops = {
1338        .func                   = event_enable_count_trigger,
1339        .print                  = event_enable_trigger_print,
1340        .init                   = event_trigger_init,
1341        .free                   = event_enable_trigger_free,
1342};
1343
1344int event_enable_trigger_func(struct event_command *cmd_ops,
1345                              struct trace_event_file *file,
1346                              char *glob, char *cmd, char *param)
1347{
1348        struct trace_event_file *event_enable_file;
1349        struct enable_trigger_data *enable_data;
1350        struct event_trigger_data *trigger_data;
1351        struct event_trigger_ops *trigger_ops;
1352        struct trace_array *tr = file->tr;
1353        const char *system;
1354        const char *event;
1355        bool hist = false;
1356        char *trigger;
1357        char *number;
1358        bool enable;
1359        int ret;
1360
1361        if (!param)
1362                return -EINVAL;
1363
1364        /* separate the trigger from the filter (s:e:n [if filter]) */
1365        trigger = strsep(&param, " \t");
1366        if (!trigger)
1367                return -EINVAL;
1368
1369        system = strsep(&trigger, ":");
1370        if (!trigger)
1371                return -EINVAL;
1372
1373        event = strsep(&trigger, ":");
1374
1375        ret = -EINVAL;
1376        event_enable_file = find_event_file(tr, system, event);
1377        if (!event_enable_file)
1378                goto out;
1379
1380#ifdef CONFIG_HIST_TRIGGERS
1381        hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1382                (strcmp(cmd, DISABLE_HIST_STR) == 0));
1383
1384        enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1385                  (strcmp(cmd, ENABLE_HIST_STR) == 0));
1386#else
1387        enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1388#endif
1389        trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1390
1391        ret = -ENOMEM;
1392        trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1393        if (!trigger_data)
1394                goto out;
1395
1396        enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1397        if (!enable_data) {
1398                kfree(trigger_data);
1399                goto out;
1400        }
1401
1402        trigger_data->count = -1;
1403        trigger_data->ops = trigger_ops;
1404        trigger_data->cmd_ops = cmd_ops;
1405        INIT_LIST_HEAD(&trigger_data->list);
1406        RCU_INIT_POINTER(trigger_data->filter, NULL);
1407
1408        enable_data->hist = hist;
1409        enable_data->enable = enable;
1410        enable_data->file = event_enable_file;
1411        trigger_data->private_data = enable_data;
1412
1413        if (glob[0] == '!') {
1414                cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1415                kfree(trigger_data);
1416                kfree(enable_data);
1417                ret = 0;
1418                goto out;
1419        }
1420
1421        /* Up the trigger_data count to make sure nothing frees it on failure */
1422        event_trigger_init(trigger_ops, trigger_data);
1423
1424        if (trigger) {
1425                number = strsep(&trigger, ":");
1426
1427                ret = -EINVAL;
1428                if (!strlen(number))
1429                        goto out_free;
1430
1431                /*
1432                 * We use the callback data field (which is a pointer)
1433                 * as our counter.
1434                 */
1435                ret = kstrtoul(number, 0, &trigger_data->count);
1436                if (ret)
1437                        goto out_free;
1438        }
1439
1440        if (!param) /* if param is non-empty, it's supposed to be a filter */
1441                goto out_reg;
1442
1443        if (!cmd_ops->set_filter)
1444                goto out_reg;
1445
1446        ret = cmd_ops->set_filter(param, trigger_data, file);
1447        if (ret < 0)
1448                goto out_free;
1449
1450 out_reg:
1451        /* Don't let event modules unload while probe registered */
1452        ret = try_module_get(event_enable_file->event_call->mod);
1453        if (!ret) {
1454                ret = -EBUSY;
1455                goto out_free;
1456        }
1457
1458        ret = trace_event_enable_disable(event_enable_file, 1, 1);
1459        if (ret < 0)
1460                goto out_put;
1461        ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1462        /*
1463         * The above returns on success the # of functions enabled,
1464         * but if it didn't find any functions it returns zero.
1465         * Consider no functions a failure too.
1466         */
1467        if (!ret) {
1468                ret = -ENOENT;
1469                goto out_disable;
1470        } else if (ret < 0)
1471                goto out_disable;
1472        /* Just return zero, not the number of enabled functions */
1473        ret = 0;
1474        event_trigger_free(trigger_ops, trigger_data);
1475 out:
1476        return ret;
1477
1478 out_disable:
1479        trace_event_enable_disable(event_enable_file, 0, 1);
1480 out_put:
1481        module_put(event_enable_file->event_call->mod);
1482 out_free:
1483        if (cmd_ops->set_filter)
1484                cmd_ops->set_filter(NULL, trigger_data, NULL);
1485        event_trigger_free(trigger_ops, trigger_data);
1486        kfree(enable_data);
1487        goto out;
1488}
1489
1490int event_enable_register_trigger(char *glob,
1491                                  struct event_trigger_ops *ops,
1492                                  struct event_trigger_data *data,
1493                                  struct trace_event_file *file)
1494{
1495        struct enable_trigger_data *enable_data = data->private_data;
1496        struct enable_trigger_data *test_enable_data;
1497        struct event_trigger_data *test;
1498        int ret = 0;
1499
1500        list_for_each_entry_rcu(test, &file->triggers, list) {
1501                test_enable_data = test->private_data;
1502                if (test_enable_data &&
1503                    (test->cmd_ops->trigger_type ==
1504                     data->cmd_ops->trigger_type) &&
1505                    (test_enable_data->file == enable_data->file)) {
1506                        ret = -EEXIST;
1507                        goto out;
1508                }
1509        }
1510
1511        if (data->ops->init) {
1512                ret = data->ops->init(data->ops, data);
1513                if (ret < 0)
1514                        goto out;
1515        }
1516
1517        list_add_rcu(&data->list, &file->triggers);
1518        ret++;
1519
1520        update_cond_flag(file);
1521        if (trace_event_trigger_enable_disable(file, 1) < 0) {
1522                list_del_rcu(&data->list);
1523                update_cond_flag(file);
1524                ret--;
1525        }
1526out:
1527        return ret;
1528}
1529
1530void event_enable_unregister_trigger(char *glob,
1531                                     struct event_trigger_ops *ops,
1532                                     struct event_trigger_data *test,
1533                                     struct trace_event_file *file)
1534{
1535        struct enable_trigger_data *test_enable_data = test->private_data;
1536        struct enable_trigger_data *enable_data;
1537        struct event_trigger_data *data;
1538        bool unregistered = false;
1539
1540        list_for_each_entry_rcu(data, &file->triggers, list) {
1541                enable_data = data->private_data;
1542                if (enable_data &&
1543                    (data->cmd_ops->trigger_type ==
1544                     test->cmd_ops->trigger_type) &&
1545                    (enable_data->file == test_enable_data->file)) {
1546                        unregistered = true;
1547                        list_del_rcu(&data->list);
1548                        trace_event_trigger_enable_disable(file, 0);
1549                        update_cond_flag(file);
1550                        break;
1551                }
1552        }
1553
1554        if (unregistered && data->ops->free)
1555                data->ops->free(data->ops, data);
1556}
1557
1558static struct event_trigger_ops *
1559event_enable_get_trigger_ops(char *cmd, char *param)
1560{
1561        struct event_trigger_ops *ops;
1562        bool enable;
1563
1564#ifdef CONFIG_HIST_TRIGGERS
1565        enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1566                  (strcmp(cmd, ENABLE_HIST_STR) == 0));
1567#else
1568        enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1569#endif
1570        if (enable)
1571                ops = param ? &event_enable_count_trigger_ops :
1572                        &event_enable_trigger_ops;
1573        else
1574                ops = param ? &event_disable_count_trigger_ops :
1575                        &event_disable_trigger_ops;
1576
1577        return ops;
1578}
1579
1580static struct event_command trigger_enable_cmd = {
1581        .name                   = ENABLE_EVENT_STR,
1582        .trigger_type           = ETT_EVENT_ENABLE,
1583        .func                   = event_enable_trigger_func,
1584        .reg                    = event_enable_register_trigger,
1585        .unreg                  = event_enable_unregister_trigger,
1586        .get_trigger_ops        = event_enable_get_trigger_ops,
1587        .set_filter             = set_trigger_filter,
1588};
1589
1590static struct event_command trigger_disable_cmd = {
1591        .name                   = DISABLE_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
1600static __init void unregister_trigger_enable_disable_cmds(void)
1601{
1602        unregister_event_command(&trigger_enable_cmd);
1603        unregister_event_command(&trigger_disable_cmd);
1604}
1605
1606static __init int register_trigger_enable_disable_cmds(void)
1607{
1608        int ret;
1609
1610        ret = register_event_command(&trigger_enable_cmd);
1611        if (WARN_ON(ret < 0))
1612                return ret;
1613        ret = register_event_command(&trigger_disable_cmd);
1614        if (WARN_ON(ret < 0))
1615                unregister_trigger_enable_disable_cmds();
1616
1617        return ret;
1618}
1619
1620static __init int register_trigger_traceon_traceoff_cmds(void)
1621{
1622        int ret;
1623
1624        ret = register_event_command(&trigger_traceon_cmd);
1625        if (WARN_ON(ret < 0))
1626                return ret;
1627        ret = register_event_command(&trigger_traceoff_cmd);
1628        if (WARN_ON(ret < 0))
1629                unregister_trigger_traceon_traceoff_cmds();
1630
1631        return ret;
1632}
1633
1634__init int register_trigger_cmds(void)
1635{
1636        register_trigger_traceon_traceoff_cmds();
1637        register_trigger_snapshot_cmd();
1638        register_trigger_stacktrace_cmd();
1639        register_trigger_enable_disable_cmds();
1640        register_trigger_hist_enable_disable_cmds();
1641        register_trigger_hist_cmd();
1642
1643        return 0;
1644}
1645