linux/kernel/trace/trace_events.c
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   1/*
   2 * event tracer
   3 *
   4 * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
   5 *
   6 *  - Added format output of fields of the trace point.
   7 *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
   8 *
   9 */
  10
  11#include <linux/workqueue.h>
  12#include <linux/spinlock.h>
  13#include <linux/kthread.h>
  14#include <linux/debugfs.h>
  15#include <linux/uaccess.h>
  16#include <linux/module.h>
  17#include <linux/ctype.h>
  18#include <linux/slab.h>
  19#include <linux/delay.h>
  20
  21#include <asm/setup.h>
  22
  23#include "trace_output.h"
  24
  25#undef TRACE_SYSTEM
  26#define TRACE_SYSTEM "TRACE_SYSTEM"
  27
  28DEFINE_MUTEX(event_mutex);
  29
  30DEFINE_MUTEX(event_storage_mutex);
  31EXPORT_SYMBOL_GPL(event_storage_mutex);
  32
  33char event_storage[EVENT_STORAGE_SIZE];
  34EXPORT_SYMBOL_GPL(event_storage);
  35
  36LIST_HEAD(ftrace_events);
  37LIST_HEAD(ftrace_common_fields);
  38
  39struct list_head *
  40trace_get_fields(struct ftrace_event_call *event_call)
  41{
  42        if (!event_call->class->get_fields)
  43                return &event_call->class->fields;
  44        return event_call->class->get_fields(event_call);
  45}
  46
  47static int __trace_define_field(struct list_head *head, const char *type,
  48                                const char *name, int offset, int size,
  49                                int is_signed, int filter_type)
  50{
  51        struct ftrace_event_field *field;
  52
  53        field = kzalloc(sizeof(*field), GFP_KERNEL);
  54        if (!field)
  55                goto err;
  56
  57        field->name = kstrdup(name, GFP_KERNEL);
  58        if (!field->name)
  59                goto err;
  60
  61        field->type = kstrdup(type, GFP_KERNEL);
  62        if (!field->type)
  63                goto err;
  64
  65        if (filter_type == FILTER_OTHER)
  66                field->filter_type = filter_assign_type(type);
  67        else
  68                field->filter_type = filter_type;
  69
  70        field->offset = offset;
  71        field->size = size;
  72        field->is_signed = is_signed;
  73
  74        list_add(&field->link, head);
  75
  76        return 0;
  77
  78err:
  79        if (field)
  80                kfree(field->name);
  81        kfree(field);
  82
  83        return -ENOMEM;
  84}
  85
  86int trace_define_field(struct ftrace_event_call *call, const char *type,
  87                       const char *name, int offset, int size, int is_signed,
  88                       int filter_type)
  89{
  90        struct list_head *head;
  91
  92        if (WARN_ON(!call->class))
  93                return 0;
  94
  95        head = trace_get_fields(call);
  96        return __trace_define_field(head, type, name, offset, size,
  97                                    is_signed, filter_type);
  98}
  99EXPORT_SYMBOL_GPL(trace_define_field);
 100
 101#define __common_field(type, item)                                      \
 102        ret = __trace_define_field(&ftrace_common_fields, #type,        \
 103                                   "common_" #item,                     \
 104                                   offsetof(typeof(ent), item),         \
 105                                   sizeof(ent.item),                    \
 106                                   is_signed_type(type), FILTER_OTHER); \
 107        if (ret)                                                        \
 108                return ret;
 109
 110static int trace_define_common_fields(void)
 111{
 112        int ret;
 113        struct trace_entry ent;
 114
 115        __common_field(unsigned short, type);
 116        __common_field(unsigned char, flags);
 117        __common_field(unsigned char, preempt_count);
 118        __common_field(int, pid);
 119        __common_field(int, padding);
 120
 121        return ret;
 122}
 123
 124void trace_destroy_fields(struct ftrace_event_call *call)
 125{
 126        struct ftrace_event_field *field, *next;
 127        struct list_head *head;
 128
 129        head = trace_get_fields(call);
 130        list_for_each_entry_safe(field, next, head, link) {
 131                list_del(&field->link);
 132                kfree(field->type);
 133                kfree(field->name);
 134                kfree(field);
 135        }
 136}
 137
 138int trace_event_raw_init(struct ftrace_event_call *call)
 139{
 140        int id;
 141
 142        id = register_ftrace_event(&call->event);
 143        if (!id)
 144                return -ENODEV;
 145
 146        return 0;
 147}
 148EXPORT_SYMBOL_GPL(trace_event_raw_init);
 149
 150int ftrace_event_reg(struct ftrace_event_call *call,
 151                     enum trace_reg type, void *data)
 152{
 153        switch (type) {
 154        case TRACE_REG_REGISTER:
 155                return tracepoint_probe_register(call->name,
 156                                                 call->class->probe,
 157                                                 call);
 158        case TRACE_REG_UNREGISTER:
 159                tracepoint_probe_unregister(call->name,
 160                                            call->class->probe,
 161                                            call);
 162                return 0;
 163
 164#ifdef CONFIG_PERF_EVENTS
 165        case TRACE_REG_PERF_REGISTER:
 166                return tracepoint_probe_register(call->name,
 167                                                 call->class->perf_probe,
 168                                                 call);
 169        case TRACE_REG_PERF_UNREGISTER:
 170                tracepoint_probe_unregister(call->name,
 171                                            call->class->perf_probe,
 172                                            call);
 173                return 0;
 174        case TRACE_REG_PERF_OPEN:
 175        case TRACE_REG_PERF_CLOSE:
 176        case TRACE_REG_PERF_ADD:
 177        case TRACE_REG_PERF_DEL:
 178                return 0;
 179#endif
 180        }
 181        return 0;
 182}
 183EXPORT_SYMBOL_GPL(ftrace_event_reg);
 184
 185void trace_event_enable_cmd_record(bool enable)
 186{
 187        struct ftrace_event_call *call;
 188
 189        mutex_lock(&event_mutex);
 190        list_for_each_entry(call, &ftrace_events, list) {
 191                if (!(call->flags & TRACE_EVENT_FL_ENABLED))
 192                        continue;
 193
 194                if (enable) {
 195                        tracing_start_cmdline_record();
 196                        call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
 197                } else {
 198                        tracing_stop_cmdline_record();
 199                        call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
 200                }
 201        }
 202        mutex_unlock(&event_mutex);
 203}
 204
 205static int ftrace_event_enable_disable(struct ftrace_event_call *call,
 206                                        int enable)
 207{
 208        int ret = 0;
 209
 210        switch (enable) {
 211        case 0:
 212                if (call->flags & TRACE_EVENT_FL_ENABLED) {
 213                        call->flags &= ~TRACE_EVENT_FL_ENABLED;
 214                        if (call->flags & TRACE_EVENT_FL_RECORDED_CMD) {
 215                                tracing_stop_cmdline_record();
 216                                call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
 217                        }
 218                        call->class->reg(call, TRACE_REG_UNREGISTER, NULL);
 219                }
 220                break;
 221        case 1:
 222                if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
 223                        if (trace_flags & TRACE_ITER_RECORD_CMD) {
 224                                tracing_start_cmdline_record();
 225                                call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
 226                        }
 227                        ret = call->class->reg(call, TRACE_REG_REGISTER, NULL);
 228                        if (ret) {
 229                                tracing_stop_cmdline_record();
 230                                pr_info("event trace: Could not enable event "
 231                                        "%s\n", call->name);
 232                                break;
 233                        }
 234                        call->flags |= TRACE_EVENT_FL_ENABLED;
 235                }
 236                break;
 237        }
 238
 239        return ret;
 240}
 241
 242static void ftrace_clear_events(void)
 243{
 244        struct ftrace_event_call *call;
 245
 246        mutex_lock(&event_mutex);
 247        list_for_each_entry(call, &ftrace_events, list) {
 248                ftrace_event_enable_disable(call, 0);
 249        }
 250        mutex_unlock(&event_mutex);
 251}
 252
 253static void __put_system(struct event_subsystem *system)
 254{
 255        struct event_filter *filter = system->filter;
 256
 257        WARN_ON_ONCE(system->ref_count == 0);
 258        if (--system->ref_count)
 259                return;
 260
 261        if (filter) {
 262                kfree(filter->filter_string);
 263                kfree(filter);
 264        }
 265        kfree(system->name);
 266        kfree(system);
 267}
 268
 269static void __get_system(struct event_subsystem *system)
 270{
 271        WARN_ON_ONCE(system->ref_count == 0);
 272        system->ref_count++;
 273}
 274
 275static void put_system(struct event_subsystem *system)
 276{
 277        mutex_lock(&event_mutex);
 278        __put_system(system);
 279        mutex_unlock(&event_mutex);
 280}
 281
 282/*
 283 * __ftrace_set_clr_event(NULL, NULL, NULL, set) will set/unset all events.
 284 */
 285static int __ftrace_set_clr_event(const char *match, const char *sub,
 286                                  const char *event, int set)
 287{
 288        struct ftrace_event_call *call;
 289        int ret = -EINVAL;
 290
 291        mutex_lock(&event_mutex);
 292        list_for_each_entry(call, &ftrace_events, list) {
 293
 294                if (!call->name || !call->class || !call->class->reg)
 295                        continue;
 296
 297                if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
 298                        continue;
 299
 300                if (match &&
 301                    strcmp(match, call->name) != 0 &&
 302                    strcmp(match, call->class->system) != 0)
 303                        continue;
 304
 305                if (sub && strcmp(sub, call->class->system) != 0)
 306                        continue;
 307
 308                if (event && strcmp(event, call->name) != 0)
 309                        continue;
 310
 311                ftrace_event_enable_disable(call, set);
 312
 313                ret = 0;
 314        }
 315        mutex_unlock(&event_mutex);
 316
 317        return ret;
 318}
 319
 320static int ftrace_set_clr_event(char *buf, int set)
 321{
 322        char *event = NULL, *sub = NULL, *match;
 323
 324        /*
 325         * The buf format can be <subsystem>:<event-name>
 326         *  *:<event-name> means any event by that name.
 327         *  :<event-name> is the same.
 328         *
 329         *  <subsystem>:* means all events in that subsystem
 330         *  <subsystem>: means the same.
 331         *
 332         *  <name> (no ':') means all events in a subsystem with
 333         *  the name <name> or any event that matches <name>
 334         */
 335
 336        match = strsep(&buf, ":");
 337        if (buf) {
 338                sub = match;
 339                event = buf;
 340                match = NULL;
 341
 342                if (!strlen(sub) || strcmp(sub, "*") == 0)
 343                        sub = NULL;
 344                if (!strlen(event) || strcmp(event, "*") == 0)
 345                        event = NULL;
 346        }
 347
 348        return __ftrace_set_clr_event(match, sub, event, set);
 349}
 350
 351/**
 352 * trace_set_clr_event - enable or disable an event
 353 * @system: system name to match (NULL for any system)
 354 * @event: event name to match (NULL for all events, within system)
 355 * @set: 1 to enable, 0 to disable
 356 *
 357 * This is a way for other parts of the kernel to enable or disable
 358 * event recording.
 359 *
 360 * Returns 0 on success, -EINVAL if the parameters do not match any
 361 * registered events.
 362 */
 363int trace_set_clr_event(const char *system, const char *event, int set)
 364{
 365        return __ftrace_set_clr_event(NULL, system, event, set);
 366}
 367EXPORT_SYMBOL_GPL(trace_set_clr_event);
 368
 369/* 128 should be much more than enough */
 370#define EVENT_BUF_SIZE          127
 371
 372static ssize_t
 373ftrace_event_write(struct file *file, const char __user *ubuf,
 374                   size_t cnt, loff_t *ppos)
 375{
 376        struct trace_parser parser;
 377        ssize_t read, ret;
 378
 379        if (!cnt)
 380                return 0;
 381
 382        ret = tracing_update_buffers();
 383        if (ret < 0)
 384                return ret;
 385
 386        if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
 387                return -ENOMEM;
 388
 389        read = trace_get_user(&parser, ubuf, cnt, ppos);
 390
 391        if (read >= 0 && trace_parser_loaded((&parser))) {
 392                int set = 1;
 393
 394                if (*parser.buffer == '!')
 395                        set = 0;
 396
 397                parser.buffer[parser.idx] = 0;
 398
 399                ret = ftrace_set_clr_event(parser.buffer + !set, set);
 400                if (ret)
 401                        goto out_put;
 402        }
 403
 404        ret = read;
 405
 406 out_put:
 407        trace_parser_put(&parser);
 408
 409        return ret;
 410}
 411
 412static void *
 413t_next(struct seq_file *m, void *v, loff_t *pos)
 414{
 415        struct ftrace_event_call *call = v;
 416
 417        (*pos)++;
 418
 419        list_for_each_entry_continue(call, &ftrace_events, list) {
 420                /*
 421                 * The ftrace subsystem is for showing formats only.
 422                 * They can not be enabled or disabled via the event files.
 423                 */
 424                if (call->class && call->class->reg)
 425                        return call;
 426        }
 427
 428        return NULL;
 429}
 430
 431static void *t_start(struct seq_file *m, loff_t *pos)
 432{
 433        struct ftrace_event_call *call;
 434        loff_t l;
 435
 436        mutex_lock(&event_mutex);
 437
 438        call = list_entry(&ftrace_events, struct ftrace_event_call, list);
 439        for (l = 0; l <= *pos; ) {
 440                call = t_next(m, call, &l);
 441                if (!call)
 442                        break;
 443        }
 444        return call;
 445}
 446
 447static void *
 448s_next(struct seq_file *m, void *v, loff_t *pos)
 449{
 450        struct ftrace_event_call *call = v;
 451
 452        (*pos)++;
 453
 454        list_for_each_entry_continue(call, &ftrace_events, list) {
 455                if (call->flags & TRACE_EVENT_FL_ENABLED)
 456                        return call;
 457        }
 458
 459        return NULL;
 460}
 461
 462static void *s_start(struct seq_file *m, loff_t *pos)
 463{
 464        struct ftrace_event_call *call;
 465        loff_t l;
 466
 467        mutex_lock(&event_mutex);
 468
 469        call = list_entry(&ftrace_events, struct ftrace_event_call, list);
 470        for (l = 0; l <= *pos; ) {
 471                call = s_next(m, call, &l);
 472                if (!call)
 473                        break;
 474        }
 475        return call;
 476}
 477
 478static int t_show(struct seq_file *m, void *v)
 479{
 480        struct ftrace_event_call *call = v;
 481
 482        if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
 483                seq_printf(m, "%s:", call->class->system);
 484        seq_printf(m, "%s\n", call->name);
 485
 486        return 0;
 487}
 488
 489static void t_stop(struct seq_file *m, void *p)
 490{
 491        mutex_unlock(&event_mutex);
 492}
 493
 494static int
 495ftrace_event_seq_open(struct inode *inode, struct file *file)
 496{
 497        const struct seq_operations *seq_ops;
 498
 499        if ((file->f_mode & FMODE_WRITE) &&
 500            (file->f_flags & O_TRUNC))
 501                ftrace_clear_events();
 502
 503        seq_ops = inode->i_private;
 504        return seq_open(file, seq_ops);
 505}
 506
 507static ssize_t
 508event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 509                  loff_t *ppos)
 510{
 511        struct ftrace_event_call *call = filp->private_data;
 512        char *buf;
 513
 514        if (call->flags & TRACE_EVENT_FL_ENABLED)
 515                buf = "1\n";
 516        else
 517                buf = "0\n";
 518
 519        return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 520}
 521
 522static ssize_t
 523event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 524                   loff_t *ppos)
 525{
 526        struct ftrace_event_call *call = filp->private_data;
 527        unsigned long val;
 528        int ret;
 529
 530        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 531        if (ret)
 532                return ret;
 533
 534        ret = tracing_update_buffers();
 535        if (ret < 0)
 536                return ret;
 537
 538        switch (val) {
 539        case 0:
 540        case 1:
 541                mutex_lock(&event_mutex);
 542                ret = ftrace_event_enable_disable(call, val);
 543                mutex_unlock(&event_mutex);
 544                break;
 545
 546        default:
 547                return -EINVAL;
 548        }
 549
 550        *ppos += cnt;
 551
 552        return ret ? ret : cnt;
 553}
 554
 555static ssize_t
 556system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 557                   loff_t *ppos)
 558{
 559        const char set_to_char[4] = { '?', '0', '1', 'X' };
 560        struct event_subsystem *system = filp->private_data;
 561        struct ftrace_event_call *call;
 562        char buf[2];
 563        int set = 0;
 564        int ret;
 565
 566        mutex_lock(&event_mutex);
 567        list_for_each_entry(call, &ftrace_events, list) {
 568                if (!call->name || !call->class || !call->class->reg)
 569                        continue;
 570
 571                if (system && strcmp(call->class->system, system->name) != 0)
 572                        continue;
 573
 574                /*
 575                 * We need to find out if all the events are set
 576                 * or if all events or cleared, or if we have
 577                 * a mixture.
 578                 */
 579                set |= (1 << !!(call->flags & TRACE_EVENT_FL_ENABLED));
 580
 581                /*
 582                 * If we have a mixture, no need to look further.
 583                 */
 584                if (set == 3)
 585                        break;
 586        }
 587        mutex_unlock(&event_mutex);
 588
 589        buf[0] = set_to_char[set];
 590        buf[1] = '\n';
 591
 592        ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 593
 594        return ret;
 595}
 596
 597static ssize_t
 598system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 599                    loff_t *ppos)
 600{
 601        struct event_subsystem *system = filp->private_data;
 602        const char *name = NULL;
 603        unsigned long val;
 604        ssize_t ret;
 605
 606        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 607        if (ret)
 608                return ret;
 609
 610        ret = tracing_update_buffers();
 611        if (ret < 0)
 612                return ret;
 613
 614        if (val != 0 && val != 1)
 615                return -EINVAL;
 616
 617        /*
 618         * Opening of "enable" adds a ref count to system,
 619         * so the name is safe to use.
 620         */
 621        if (system)
 622                name = system->name;
 623
 624        ret = __ftrace_set_clr_event(NULL, name, NULL, val);
 625        if (ret)
 626                goto out;
 627
 628        ret = cnt;
 629
 630out:
 631        *ppos += cnt;
 632
 633        return ret;
 634}
 635
 636enum {
 637        FORMAT_HEADER           = 1,
 638        FORMAT_FIELD_SEPERATOR  = 2,
 639        FORMAT_PRINTFMT         = 3,
 640};
 641
 642static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 643{
 644        struct ftrace_event_call *call = m->private;
 645        struct ftrace_event_field *field;
 646        struct list_head *common_head = &ftrace_common_fields;
 647        struct list_head *head = trace_get_fields(call);
 648
 649        (*pos)++;
 650
 651        switch ((unsigned long)v) {
 652        case FORMAT_HEADER:
 653                if (unlikely(list_empty(common_head)))
 654                        return NULL;
 655
 656                field = list_entry(common_head->prev,
 657                                   struct ftrace_event_field, link);
 658                return field;
 659
 660        case FORMAT_FIELD_SEPERATOR:
 661                if (unlikely(list_empty(head)))
 662                        return NULL;
 663
 664                field = list_entry(head->prev, struct ftrace_event_field, link);
 665                return field;
 666
 667        case FORMAT_PRINTFMT:
 668                /* all done */
 669                return NULL;
 670        }
 671
 672        field = v;
 673        if (field->link.prev == common_head)
 674                return (void *)FORMAT_FIELD_SEPERATOR;
 675        else if (field->link.prev == head)
 676                return (void *)FORMAT_PRINTFMT;
 677
 678        field = list_entry(field->link.prev, struct ftrace_event_field, link);
 679
 680        return field;
 681}
 682
 683static void *f_start(struct seq_file *m, loff_t *pos)
 684{
 685        loff_t l = 0;
 686        void *p;
 687
 688        /* Start by showing the header */
 689        if (!*pos)
 690                return (void *)FORMAT_HEADER;
 691
 692        p = (void *)FORMAT_HEADER;
 693        do {
 694                p = f_next(m, p, &l);
 695        } while (p && l < *pos);
 696
 697        return p;
 698}
 699
 700static int f_show(struct seq_file *m, void *v)
 701{
 702        struct ftrace_event_call *call = m->private;
 703        struct ftrace_event_field *field;
 704        const char *array_descriptor;
 705
 706        switch ((unsigned long)v) {
 707        case FORMAT_HEADER:
 708                seq_printf(m, "name: %s\n", call->name);
 709                seq_printf(m, "ID: %d\n", call->event.type);
 710                seq_printf(m, "format:\n");
 711                return 0;
 712
 713        case FORMAT_FIELD_SEPERATOR:
 714                seq_putc(m, '\n');
 715                return 0;
 716
 717        case FORMAT_PRINTFMT:
 718                seq_printf(m, "\nprint fmt: %s\n",
 719                           call->print_fmt);
 720                return 0;
 721        }
 722
 723        field = v;
 724
 725        /*
 726         * Smartly shows the array type(except dynamic array).
 727         * Normal:
 728         *      field:TYPE VAR
 729         * If TYPE := TYPE[LEN], it is shown:
 730         *      field:TYPE VAR[LEN]
 731         */
 732        array_descriptor = strchr(field->type, '[');
 733
 734        if (!strncmp(field->type, "__data_loc", 10))
 735                array_descriptor = NULL;
 736
 737        if (!array_descriptor)
 738                seq_printf(m, "\tfield:%s %s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
 739                           field->type, field->name, field->offset,
 740                           field->size, !!field->is_signed);
 741        else
 742                seq_printf(m, "\tfield:%.*s %s%s;\toffset:%u;\tsize:%u;\tsigned:%d;\n",
 743                           (int)(array_descriptor - field->type),
 744                           field->type, field->name,
 745                           array_descriptor, field->offset,
 746                           field->size, !!field->is_signed);
 747
 748        return 0;
 749}
 750
 751static void f_stop(struct seq_file *m, void *p)
 752{
 753}
 754
 755static const struct seq_operations trace_format_seq_ops = {
 756        .start          = f_start,
 757        .next           = f_next,
 758        .stop           = f_stop,
 759        .show           = f_show,
 760};
 761
 762static int trace_format_open(struct inode *inode, struct file *file)
 763{
 764        struct ftrace_event_call *call = inode->i_private;
 765        struct seq_file *m;
 766        int ret;
 767
 768        ret = seq_open(file, &trace_format_seq_ops);
 769        if (ret < 0)
 770                return ret;
 771
 772        m = file->private_data;
 773        m->private = call;
 774
 775        return 0;
 776}
 777
 778static ssize_t
 779event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 780{
 781        struct ftrace_event_call *call = filp->private_data;
 782        struct trace_seq *s;
 783        int r;
 784
 785        if (*ppos)
 786                return 0;
 787
 788        s = kmalloc(sizeof(*s), GFP_KERNEL);
 789        if (!s)
 790                return -ENOMEM;
 791
 792        trace_seq_init(s);
 793        trace_seq_printf(s, "%d\n", call->event.type);
 794
 795        r = simple_read_from_buffer(ubuf, cnt, ppos,
 796                                    s->buffer, s->len);
 797        kfree(s);
 798        return r;
 799}
 800
 801static ssize_t
 802event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 803                  loff_t *ppos)
 804{
 805        struct ftrace_event_call *call = filp->private_data;
 806        struct trace_seq *s;
 807        int r;
 808
 809        if (*ppos)
 810                return 0;
 811
 812        s = kmalloc(sizeof(*s), GFP_KERNEL);
 813        if (!s)
 814                return -ENOMEM;
 815
 816        trace_seq_init(s);
 817
 818        print_event_filter(call, s);
 819        r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 820
 821        kfree(s);
 822
 823        return r;
 824}
 825
 826static ssize_t
 827event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 828                   loff_t *ppos)
 829{
 830        struct ftrace_event_call *call = filp->private_data;
 831        char *buf;
 832        int err;
 833
 834        if (cnt >= PAGE_SIZE)
 835                return -EINVAL;
 836
 837        buf = (char *)__get_free_page(GFP_TEMPORARY);
 838        if (!buf)
 839                return -ENOMEM;
 840
 841        if (copy_from_user(buf, ubuf, cnt)) {
 842                free_page((unsigned long) buf);
 843                return -EFAULT;
 844        }
 845        buf[cnt] = '\0';
 846
 847        err = apply_event_filter(call, buf);
 848        free_page((unsigned long) buf);
 849        if (err < 0)
 850                return err;
 851
 852        *ppos += cnt;
 853
 854        return cnt;
 855}
 856
 857static LIST_HEAD(event_subsystems);
 858
 859static int subsystem_open(struct inode *inode, struct file *filp)
 860{
 861        struct event_subsystem *system = NULL;
 862        int ret;
 863
 864        if (!inode->i_private)
 865                goto skip_search;
 866
 867        /* Make sure the system still exists */
 868        mutex_lock(&event_mutex);
 869        list_for_each_entry(system, &event_subsystems, list) {
 870                if (system == inode->i_private) {
 871                        /* Don't open systems with no events */
 872                        if (!system->nr_events) {
 873                                system = NULL;
 874                                break;
 875                        }
 876                        __get_system(system);
 877                        break;
 878                }
 879        }
 880        mutex_unlock(&event_mutex);
 881
 882        if (system != inode->i_private)
 883                return -ENODEV;
 884
 885 skip_search:
 886        ret = tracing_open_generic(inode, filp);
 887        if (ret < 0 && system)
 888                put_system(system);
 889
 890        return ret;
 891}
 892
 893static int subsystem_release(struct inode *inode, struct file *file)
 894{
 895        struct event_subsystem *system = inode->i_private;
 896
 897        if (system)
 898                put_system(system);
 899
 900        return 0;
 901}
 902
 903static ssize_t
 904subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 905                      loff_t *ppos)
 906{
 907        struct event_subsystem *system = filp->private_data;
 908        struct trace_seq *s;
 909        int r;
 910
 911        if (*ppos)
 912                return 0;
 913
 914        s = kmalloc(sizeof(*s), GFP_KERNEL);
 915        if (!s)
 916                return -ENOMEM;
 917
 918        trace_seq_init(s);
 919
 920        print_subsystem_event_filter(system, s);
 921        r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 922
 923        kfree(s);
 924
 925        return r;
 926}
 927
 928static ssize_t
 929subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 930                       loff_t *ppos)
 931{
 932        struct event_subsystem *system = filp->private_data;
 933        char *buf;
 934        int err;
 935
 936        if (cnt >= PAGE_SIZE)
 937                return -EINVAL;
 938
 939        buf = (char *)__get_free_page(GFP_TEMPORARY);
 940        if (!buf)
 941                return -ENOMEM;
 942
 943        if (copy_from_user(buf, ubuf, cnt)) {
 944                free_page((unsigned long) buf);
 945                return -EFAULT;
 946        }
 947        buf[cnt] = '\0';
 948
 949        err = apply_subsystem_event_filter(system, buf);
 950        free_page((unsigned long) buf);
 951        if (err < 0)
 952                return err;
 953
 954        *ppos += cnt;
 955
 956        return cnt;
 957}
 958
 959static ssize_t
 960show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 961{
 962        int (*func)(struct trace_seq *s) = filp->private_data;
 963        struct trace_seq *s;
 964        int r;
 965
 966        if (*ppos)
 967                return 0;
 968
 969        s = kmalloc(sizeof(*s), GFP_KERNEL);
 970        if (!s)
 971                return -ENOMEM;
 972
 973        trace_seq_init(s);
 974
 975        func(s);
 976        r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 977
 978        kfree(s);
 979
 980        return r;
 981}
 982
 983static const struct seq_operations show_event_seq_ops = {
 984        .start = t_start,
 985        .next = t_next,
 986        .show = t_show,
 987        .stop = t_stop,
 988};
 989
 990static const struct seq_operations show_set_event_seq_ops = {
 991        .start = s_start,
 992        .next = s_next,
 993        .show = t_show,
 994        .stop = t_stop,
 995};
 996
 997static const struct file_operations ftrace_avail_fops = {
 998        .open = ftrace_event_seq_open,
 999        .read = seq_read,
1000        .llseek = seq_lseek,
1001        .release = seq_release,
1002};
1003
1004static const struct file_operations ftrace_set_event_fops = {
1005        .open = ftrace_event_seq_open,
1006        .read = seq_read,
1007        .write = ftrace_event_write,
1008        .llseek = seq_lseek,
1009        .release = seq_release,
1010};
1011
1012static const struct file_operations ftrace_enable_fops = {
1013        .open = tracing_open_generic,
1014        .read = event_enable_read,
1015        .write = event_enable_write,
1016        .llseek = default_llseek,
1017};
1018
1019static const struct file_operations ftrace_event_format_fops = {
1020        .open = trace_format_open,
1021        .read = seq_read,
1022        .llseek = seq_lseek,
1023        .release = seq_release,
1024};
1025
1026static const struct file_operations ftrace_event_id_fops = {
1027        .open = tracing_open_generic,
1028        .read = event_id_read,
1029        .llseek = default_llseek,
1030};
1031
1032static const struct file_operations ftrace_event_filter_fops = {
1033        .open = tracing_open_generic,
1034        .read = event_filter_read,
1035        .write = event_filter_write,
1036        .llseek = default_llseek,
1037};
1038
1039static const struct file_operations ftrace_subsystem_filter_fops = {
1040        .open = subsystem_open,
1041        .read = subsystem_filter_read,
1042        .write = subsystem_filter_write,
1043        .llseek = default_llseek,
1044        .release = subsystem_release,
1045};
1046
1047static const struct file_operations ftrace_system_enable_fops = {
1048        .open = subsystem_open,
1049        .read = system_enable_read,
1050        .write = system_enable_write,
1051        .llseek = default_llseek,
1052        .release = subsystem_release,
1053};
1054
1055static const struct file_operations ftrace_show_header_fops = {
1056        .open = tracing_open_generic,
1057        .read = show_header,
1058        .llseek = default_llseek,
1059};
1060
1061static struct dentry *event_trace_events_dir(void)
1062{
1063        static struct dentry *d_tracer;
1064        static struct dentry *d_events;
1065
1066        if (d_events)
1067                return d_events;
1068
1069        d_tracer = tracing_init_dentry();
1070        if (!d_tracer)
1071                return NULL;
1072
1073        d_events = debugfs_create_dir("events", d_tracer);
1074        if (!d_events)
1075                pr_warning("Could not create debugfs "
1076                           "'events' directory\n");
1077
1078        return d_events;
1079}
1080
1081static struct dentry *
1082event_subsystem_dir(const char *name, struct dentry *d_events)
1083{
1084        struct event_subsystem *system;
1085        struct dentry *entry;
1086
1087        /* First see if we did not already create this dir */
1088        list_for_each_entry(system, &event_subsystems, list) {
1089                if (strcmp(system->name, name) == 0) {
1090                        system->nr_events++;
1091                        return system->entry;
1092                }
1093        }
1094
1095        /* need to create new entry */
1096        system = kmalloc(sizeof(*system), GFP_KERNEL);
1097        if (!system) {
1098                pr_warning("No memory to create event subsystem %s\n",
1099                           name);
1100                return d_events;
1101        }
1102
1103        system->entry = debugfs_create_dir(name, d_events);
1104        if (!system->entry) {
1105                pr_warning("Could not create event subsystem %s\n",
1106                           name);
1107                kfree(system);
1108                return d_events;
1109        }
1110
1111        system->nr_events = 1;
1112        system->ref_count = 1;
1113        system->name = kstrdup(name, GFP_KERNEL);
1114        if (!system->name) {
1115                debugfs_remove(system->entry);
1116                kfree(system);
1117                return d_events;
1118        }
1119
1120        list_add(&system->list, &event_subsystems);
1121
1122        system->filter = NULL;
1123
1124        system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
1125        if (!system->filter) {
1126                pr_warning("Could not allocate filter for subsystem "
1127                           "'%s'\n", name);
1128                return system->entry;
1129        }
1130
1131        entry = debugfs_create_file("filter", 0644, system->entry, system,
1132                                    &ftrace_subsystem_filter_fops);
1133        if (!entry) {
1134                kfree(system->filter);
1135                system->filter = NULL;
1136                pr_warning("Could not create debugfs "
1137                           "'%s/filter' entry\n", name);
1138        }
1139
1140        trace_create_file("enable", 0644, system->entry, system,
1141                          &ftrace_system_enable_fops);
1142
1143        return system->entry;
1144}
1145
1146static int
1147event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
1148                 const struct file_operations *id,
1149                 const struct file_operations *enable,
1150                 const struct file_operations *filter,
1151                 const struct file_operations *format)
1152{
1153        struct list_head *head;
1154        int ret;
1155
1156        /*
1157         * If the trace point header did not define TRACE_SYSTEM
1158         * then the system would be called "TRACE_SYSTEM".
1159         */
1160        if (strcmp(call->class->system, TRACE_SYSTEM) != 0)
1161                d_events = event_subsystem_dir(call->class->system, d_events);
1162
1163        call->dir = debugfs_create_dir(call->name, d_events);
1164        if (!call->dir) {
1165                pr_warning("Could not create debugfs "
1166                           "'%s' directory\n", call->name);
1167                return -1;
1168        }
1169
1170        if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
1171                trace_create_file("enable", 0644, call->dir, call,
1172                                  enable);
1173
1174#ifdef CONFIG_PERF_EVENTS
1175        if (call->event.type && call->class->reg)
1176                trace_create_file("id", 0444, call->dir, call,
1177                                  id);
1178#endif
1179
1180        /*
1181         * Other events may have the same class. Only update
1182         * the fields if they are not already defined.
1183         */
1184        head = trace_get_fields(call);
1185        if (list_empty(head)) {
1186                ret = call->class->define_fields(call);
1187                if (ret < 0) {
1188                        pr_warning("Could not initialize trace point"
1189                                   " events/%s\n", call->name);
1190                        return ret;
1191                }
1192        }
1193        trace_create_file("filter", 0644, call->dir, call,
1194                          filter);
1195
1196        trace_create_file("format", 0444, call->dir, call,
1197                          format);
1198
1199        return 0;
1200}
1201
1202static void event_remove(struct ftrace_event_call *call)
1203{
1204        ftrace_event_enable_disable(call, 0);
1205        if (call->event.funcs)
1206                __unregister_ftrace_event(&call->event);
1207        list_del(&call->list);
1208}
1209
1210static int event_init(struct ftrace_event_call *call)
1211{
1212        int ret = 0;
1213
1214        if (WARN_ON(!call->name))
1215                return -EINVAL;
1216
1217        if (call->class->raw_init) {
1218                ret = call->class->raw_init(call);
1219                if (ret < 0 && ret != -ENOSYS)
1220                        pr_warn("Could not initialize trace events/%s\n",
1221                                call->name);
1222        }
1223
1224        return ret;
1225}
1226
1227static int
1228__trace_add_event_call(struct ftrace_event_call *call, struct module *mod,
1229                       const struct file_operations *id,
1230                       const struct file_operations *enable,
1231                       const struct file_operations *filter,
1232                       const struct file_operations *format)
1233{
1234        struct dentry *d_events;
1235        int ret;
1236
1237        ret = event_init(call);
1238        if (ret < 0)
1239                return ret;
1240
1241        d_events = event_trace_events_dir();
1242        if (!d_events)
1243                return -ENOENT;
1244
1245        ret = event_create_dir(call, d_events, id, enable, filter, format);
1246        if (!ret)
1247                list_add(&call->list, &ftrace_events);
1248        call->mod = mod;
1249
1250        return ret;
1251}
1252
1253/* Add an additional event_call dynamically */
1254int trace_add_event_call(struct ftrace_event_call *call)
1255{
1256        int ret;
1257        mutex_lock(&event_mutex);
1258        ret = __trace_add_event_call(call, NULL, &ftrace_event_id_fops,
1259                                     &ftrace_enable_fops,
1260                                     &ftrace_event_filter_fops,
1261                                     &ftrace_event_format_fops);
1262        mutex_unlock(&event_mutex);
1263        return ret;
1264}
1265
1266static void remove_subsystem_dir(const char *name)
1267{
1268        struct event_subsystem *system;
1269
1270        if (strcmp(name, TRACE_SYSTEM) == 0)
1271                return;
1272
1273        list_for_each_entry(system, &event_subsystems, list) {
1274                if (strcmp(system->name, name) == 0) {
1275                        if (!--system->nr_events) {
1276                                debugfs_remove_recursive(system->entry);
1277                                list_del(&system->list);
1278                                __put_system(system);
1279                        }
1280                        break;
1281                }
1282        }
1283}
1284
1285/*
1286 * Must be called under locking both of event_mutex and trace_event_mutex.
1287 */
1288static void __trace_remove_event_call(struct ftrace_event_call *call)
1289{
1290        event_remove(call);
1291        trace_destroy_fields(call);
1292        destroy_preds(call);
1293        debugfs_remove_recursive(call->dir);
1294        remove_subsystem_dir(call->class->system);
1295}
1296
1297/* Remove an event_call */
1298void trace_remove_event_call(struct ftrace_event_call *call)
1299{
1300        mutex_lock(&event_mutex);
1301        down_write(&trace_event_mutex);
1302        __trace_remove_event_call(call);
1303        up_write(&trace_event_mutex);
1304        mutex_unlock(&event_mutex);
1305}
1306
1307#define for_each_event(event, start, end)                       \
1308        for (event = start;                                     \
1309             (unsigned long)event < (unsigned long)end;         \
1310             event++)
1311
1312#ifdef CONFIG_MODULES
1313
1314static LIST_HEAD(ftrace_module_file_list);
1315
1316/*
1317 * Modules must own their file_operations to keep up with
1318 * reference counting.
1319 */
1320struct ftrace_module_file_ops {
1321        struct list_head                list;
1322        struct module                   *mod;
1323        struct file_operations          id;
1324        struct file_operations          enable;
1325        struct file_operations          format;
1326        struct file_operations          filter;
1327};
1328
1329static struct ftrace_module_file_ops *
1330trace_create_file_ops(struct module *mod)
1331{
1332        struct ftrace_module_file_ops *file_ops;
1333
1334        /*
1335         * This is a bit of a PITA. To allow for correct reference
1336         * counting, modules must "own" their file_operations.
1337         * To do this, we allocate the file operations that will be
1338         * used in the event directory.
1339         */
1340
1341        file_ops = kmalloc(sizeof(*file_ops), GFP_KERNEL);
1342        if (!file_ops)
1343                return NULL;
1344
1345        file_ops->mod = mod;
1346
1347        file_ops->id = ftrace_event_id_fops;
1348        file_ops->id.owner = mod;
1349
1350        file_ops->enable = ftrace_enable_fops;
1351        file_ops->enable.owner = mod;
1352
1353        file_ops->filter = ftrace_event_filter_fops;
1354        file_ops->filter.owner = mod;
1355
1356        file_ops->format = ftrace_event_format_fops;
1357        file_ops->format.owner = mod;
1358
1359        list_add(&file_ops->list, &ftrace_module_file_list);
1360
1361        return file_ops;
1362}
1363
1364static void trace_module_add_events(struct module *mod)
1365{
1366        struct ftrace_module_file_ops *file_ops = NULL;
1367        struct ftrace_event_call **call, **start, **end;
1368
1369        start = mod->trace_events;
1370        end = mod->trace_events + mod->num_trace_events;
1371
1372        if (start == end)
1373                return;
1374
1375        file_ops = trace_create_file_ops(mod);
1376        if (!file_ops)
1377                return;
1378
1379        for_each_event(call, start, end) {
1380                __trace_add_event_call(*call, mod,
1381                                       &file_ops->id, &file_ops->enable,
1382                                       &file_ops->filter, &file_ops->format);
1383        }
1384}
1385
1386static void trace_module_remove_events(struct module *mod)
1387{
1388        struct ftrace_module_file_ops *file_ops;
1389        struct ftrace_event_call *call, *p;
1390        bool found = false;
1391
1392        down_write(&trace_event_mutex);
1393        list_for_each_entry_safe(call, p, &ftrace_events, list) {
1394                if (call->mod == mod) {
1395                        found = true;
1396                        __trace_remove_event_call(call);
1397                }
1398        }
1399
1400        /* Now free the file_operations */
1401        list_for_each_entry(file_ops, &ftrace_module_file_list, list) {
1402                if (file_ops->mod == mod)
1403                        break;
1404        }
1405        if (&file_ops->list != &ftrace_module_file_list) {
1406                list_del(&file_ops->list);
1407                kfree(file_ops);
1408        }
1409
1410        /*
1411         * It is safest to reset the ring buffer if the module being unloaded
1412         * registered any events.
1413         */
1414        if (found)
1415                tracing_reset_current_online_cpus();
1416        up_write(&trace_event_mutex);
1417}
1418
1419static int trace_module_notify(struct notifier_block *self,
1420                               unsigned long val, void *data)
1421{
1422        struct module *mod = data;
1423
1424        mutex_lock(&event_mutex);
1425        switch (val) {
1426        case MODULE_STATE_COMING:
1427                trace_module_add_events(mod);
1428                break;
1429        case MODULE_STATE_GOING:
1430                trace_module_remove_events(mod);
1431                break;
1432        }
1433        mutex_unlock(&event_mutex);
1434
1435        return 0;
1436}
1437#else
1438static int trace_module_notify(struct notifier_block *self,
1439                               unsigned long val, void *data)
1440{
1441        return 0;
1442}
1443#endif /* CONFIG_MODULES */
1444
1445static struct notifier_block trace_module_nb = {
1446        .notifier_call = trace_module_notify,
1447        .priority = 0,
1448};
1449
1450extern struct ftrace_event_call *__start_ftrace_events[];
1451extern struct ftrace_event_call *__stop_ftrace_events[];
1452
1453static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
1454
1455static __init int setup_trace_event(char *str)
1456{
1457        strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
1458        ring_buffer_expanded = 1;
1459        tracing_selftest_disabled = 1;
1460
1461        return 1;
1462}
1463__setup("trace_event=", setup_trace_event);
1464
1465static __init int event_trace_enable(void)
1466{
1467        struct ftrace_event_call **iter, *call;
1468        char *buf = bootup_event_buf;
1469        char *token;
1470        int ret;
1471
1472        for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {
1473
1474                call = *iter;
1475                ret = event_init(call);
1476                if (!ret)
1477                        list_add(&call->list, &ftrace_events);
1478        }
1479
1480        while (true) {
1481                token = strsep(&buf, ",");
1482
1483                if (!token)
1484                        break;
1485                if (!*token)
1486                        continue;
1487
1488                ret = ftrace_set_clr_event(token, 1);
1489                if (ret)
1490                        pr_warn("Failed to enable trace event: %s\n", token);
1491        }
1492        return 0;
1493}
1494
1495static __init int event_trace_init(void)
1496{
1497        struct ftrace_event_call *call;
1498        struct dentry *d_tracer;
1499        struct dentry *entry;
1500        struct dentry *d_events;
1501        int ret;
1502
1503        d_tracer = tracing_init_dentry();
1504        if (!d_tracer)
1505                return 0;
1506
1507        entry = debugfs_create_file("available_events", 0444, d_tracer,
1508                                    (void *)&show_event_seq_ops,
1509                                    &ftrace_avail_fops);
1510        if (!entry)
1511                pr_warning("Could not create debugfs "
1512                           "'available_events' entry\n");
1513
1514        entry = debugfs_create_file("set_event", 0644, d_tracer,
1515                                    (void *)&show_set_event_seq_ops,
1516                                    &ftrace_set_event_fops);
1517        if (!entry)
1518                pr_warning("Could not create debugfs "
1519                           "'set_event' entry\n");
1520
1521        d_events = event_trace_events_dir();
1522        if (!d_events)
1523                return 0;
1524
1525        /* ring buffer internal formats */
1526        trace_create_file("header_page", 0444, d_events,
1527                          ring_buffer_print_page_header,
1528                          &ftrace_show_header_fops);
1529
1530        trace_create_file("header_event", 0444, d_events,
1531                          ring_buffer_print_entry_header,
1532                          &ftrace_show_header_fops);
1533
1534        trace_create_file("enable", 0644, d_events,
1535                          NULL, &ftrace_system_enable_fops);
1536
1537        if (trace_define_common_fields())
1538                pr_warning("tracing: Failed to allocate common fields");
1539
1540        /*
1541         * Early initialization already enabled ftrace event.
1542         * Now it's only necessary to create the event directory.
1543         */
1544        list_for_each_entry(call, &ftrace_events, list) {
1545
1546                ret = event_create_dir(call, d_events,
1547                                       &ftrace_event_id_fops,
1548                                       &ftrace_enable_fops,
1549                                       &ftrace_event_filter_fops,
1550                                       &ftrace_event_format_fops);
1551                if (ret < 0)
1552                        event_remove(call);
1553        }
1554
1555        ret = register_module_notifier(&trace_module_nb);
1556        if (ret)
1557                pr_warning("Failed to register trace events module notifier\n");
1558
1559        return 0;
1560}
1561core_initcall(event_trace_enable);
1562fs_initcall(event_trace_init);
1563
1564#ifdef CONFIG_FTRACE_STARTUP_TEST
1565
1566static DEFINE_SPINLOCK(test_spinlock);
1567static DEFINE_SPINLOCK(test_spinlock_irq);
1568static DEFINE_MUTEX(test_mutex);
1569
1570static __init void test_work(struct work_struct *dummy)
1571{
1572        spin_lock(&test_spinlock);
1573        spin_lock_irq(&test_spinlock_irq);
1574        udelay(1);
1575        spin_unlock_irq(&test_spinlock_irq);
1576        spin_unlock(&test_spinlock);
1577
1578        mutex_lock(&test_mutex);
1579        msleep(1);
1580        mutex_unlock(&test_mutex);
1581}
1582
1583static __init int event_test_thread(void *unused)
1584{
1585        void *test_malloc;
1586
1587        test_malloc = kmalloc(1234, GFP_KERNEL);
1588        if (!test_malloc)
1589                pr_info("failed to kmalloc\n");
1590
1591        schedule_on_each_cpu(test_work);
1592
1593        kfree(test_malloc);
1594
1595        set_current_state(TASK_INTERRUPTIBLE);
1596        while (!kthread_should_stop())
1597                schedule();
1598
1599        return 0;
1600}
1601
1602/*
1603 * Do various things that may trigger events.
1604 */
1605static __init void event_test_stuff(void)
1606{
1607        struct task_struct *test_thread;
1608
1609        test_thread = kthread_run(event_test_thread, NULL, "test-events");
1610        msleep(1);
1611        kthread_stop(test_thread);
1612}
1613
1614/*
1615 * For every trace event defined, we will test each trace point separately,
1616 * and then by groups, and finally all trace points.
1617 */
1618static __init void event_trace_self_tests(void)
1619{
1620        struct ftrace_event_call *call;
1621        struct event_subsystem *system;
1622        int ret;
1623
1624        pr_info("Running tests on trace events:\n");
1625
1626        list_for_each_entry(call, &ftrace_events, list) {
1627
1628                /* Only test those that have a probe */
1629                if (!call->class || !call->class->probe)
1630                        continue;
1631
1632/*
1633 * Testing syscall events here is pretty useless, but
1634 * we still do it if configured. But this is time consuming.
1635 * What we really need is a user thread to perform the
1636 * syscalls as we test.
1637 */
1638#ifndef CONFIG_EVENT_TRACE_TEST_SYSCALLS
1639                if (call->class->system &&
1640                    strcmp(call->class->system, "syscalls") == 0)
1641                        continue;
1642#endif
1643
1644                pr_info("Testing event %s: ", call->name);
1645
1646                /*
1647                 * If an event is already enabled, someone is using
1648                 * it and the self test should not be on.
1649                 */
1650                if (call->flags & TRACE_EVENT_FL_ENABLED) {
1651                        pr_warning("Enabled event during self test!\n");
1652                        WARN_ON_ONCE(1);
1653                        continue;
1654                }
1655
1656                ftrace_event_enable_disable(call, 1);
1657                event_test_stuff();
1658                ftrace_event_enable_disable(call, 0);
1659
1660                pr_cont("OK\n");
1661        }
1662
1663        /* Now test at the sub system level */
1664
1665        pr_info("Running tests on trace event systems:\n");
1666
1667        list_for_each_entry(system, &event_subsystems, list) {
1668
1669                /* the ftrace system is special, skip it */
1670                if (strcmp(system->name, "ftrace") == 0)
1671                        continue;
1672
1673                pr_info("Testing event system %s: ", system->name);
1674
1675                ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
1676                if (WARN_ON_ONCE(ret)) {
1677                        pr_warning("error enabling system %s\n",
1678                                   system->name);
1679                        continue;
1680                }
1681
1682                event_test_stuff();
1683
1684                ret = __ftrace_set_clr_event(NULL, system->name, NULL, 0);
1685                if (WARN_ON_ONCE(ret)) {
1686                        pr_warning("error disabling system %s\n",
1687                                   system->name);
1688                        continue;
1689                }
1690
1691                pr_cont("OK\n");
1692        }
1693
1694        /* Test with all events enabled */
1695
1696        pr_info("Running tests on all trace events:\n");
1697        pr_info("Testing all events: ");
1698
1699        ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
1700        if (WARN_ON_ONCE(ret)) {
1701                pr_warning("error enabling all events\n");
1702                return;
1703        }
1704
1705        event_test_stuff();
1706
1707        /* reset sysname */
1708        ret = __ftrace_set_clr_event(NULL, NULL, NULL, 0);
1709        if (WARN_ON_ONCE(ret)) {
1710                pr_warning("error disabling all events\n");
1711                return;
1712        }
1713
1714        pr_cont("OK\n");
1715}
1716
1717#ifdef CONFIG_FUNCTION_TRACER
1718
1719static DEFINE_PER_CPU(atomic_t, ftrace_test_event_disable);
1720
1721static void
1722function_test_events_call(unsigned long ip, unsigned long parent_ip,
1723                          struct ftrace_ops *op, struct pt_regs *pt_regs)
1724{
1725        struct ring_buffer_event *event;
1726        struct ring_buffer *buffer;
1727        struct ftrace_entry *entry;
1728        unsigned long flags;
1729        long disabled;
1730        int cpu;
1731        int pc;
1732
1733        pc = preempt_count();
1734        preempt_disable_notrace();
1735        cpu = raw_smp_processor_id();
1736        disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
1737
1738        if (disabled != 1)
1739                goto out;
1740
1741        local_save_flags(flags);
1742
1743        event = trace_current_buffer_lock_reserve(&buffer,
1744                                                  TRACE_FN, sizeof(*entry),
1745                                                  flags, pc);
1746        if (!event)
1747                goto out;
1748        entry   = ring_buffer_event_data(event);
1749        entry->ip                       = ip;
1750        entry->parent_ip                = parent_ip;
1751
1752        trace_nowake_buffer_unlock_commit(buffer, event, flags, pc);
1753
1754 out:
1755        atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
1756        preempt_enable_notrace();
1757}
1758
1759static struct ftrace_ops trace_ops __initdata  =
1760{
1761        .func = function_test_events_call,
1762        .flags = FTRACE_OPS_FL_RECURSION_SAFE,
1763};
1764
1765static __init void event_trace_self_test_with_function(void)
1766{
1767        int ret;
1768        ret = register_ftrace_function(&trace_ops);
1769        if (WARN_ON(ret < 0)) {
1770                pr_info("Failed to enable function tracer for event tests\n");
1771                return;
1772        }
1773        pr_info("Running tests again, along with the function tracer\n");
1774        event_trace_self_tests();
1775        unregister_ftrace_function(&trace_ops);
1776}
1777#else
1778static __init void event_trace_self_test_with_function(void)
1779{
1780}
1781#endif
1782
1783static __init int event_trace_self_tests_init(void)
1784{
1785        if (!tracing_selftest_disabled) {
1786                event_trace_self_tests();
1787                event_trace_self_test_with_function();
1788        }
1789
1790        return 0;
1791}
1792
1793late_initcall(event_trace_self_tests_init);
1794
1795#endif
1796
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